WorldWideScience

Sample records for magma energy extraction

  1. Magma Chambers, Thermal Energy, and the Unsuccessful Search for a Magma Chamber Thermostat

    Science.gov (United States)

    Glazner, A. F.

    2015-12-01

    Although the traditional concept that plutons are the frozen corpses of huge, highly liquid magma chambers ("big red blobs") is losing favor, the related notion that magma bodies can spend long periods of time (~106years) in a mushy, highly crystalline state is widely accepted. However, analysis of the thermal balance of magmatic systems indicates that it is difficult to maintain a significant portion in a simmering, mushy state, whether or not the system is eutectic-like. Magma bodies cool primarily by loss of heat to the Earth's surface. The balance between cooling via energy loss to the surface and heating via magma accretion can be denoted as M = ρLa/q, where ρ is magma density, L is latent heat of crystallization, a is the vertical rate of magma accretion, and q is surface heat flux. If M>1, then magma accretion outpaces cooling and a magma chamber forms. For reasonable values of ρ, L, and q, the rate of accretion amust be > ~15 mm/yr to form a persistent volume above the solidus. This rate is extremely high, an order of magnitude faster than estimated pluton-filling rates, and would produce a body 10 km thick in 700 ka, an order of magnitude faster than geochronology indicates. Regardless of the rate of magma supply, the proportion of crystals in the system must vary dramatically with depth at any given time owing to transfer of heat. Mechanical stirring (e.g., by convection) could serve to homogenize crystal content in a magma body, but this is unachievable in crystal-rich, locked-up magma. Without convection the lower part of the magma body becomes much hotter than the top—a process familiar to anyone who has scorched a pot of oatmeal. Thermal models that succeed in producing persistent, large bodies of magma rely on scenarios that are unrealistic (e.g., omitting heat loss to the planet's surface), self-fulfilling prophecies (e.g., setting unnaturally high temperatures as fixed boundary conditions), or physically unreasonable (e.g., magma is intruded

  2. Drilling Magma for Science, Volcano Monitoring, and Energy

    Science.gov (United States)

    Eichelberger, J. C.; Lavallée, Y.; Blankenship, D.

    2017-12-01

    location and properties of magma to calibrate geophysics (Brown et al, this session) and understand signals of "unrest". How can we not make such observations when there is so much to learn, so much at stake in correctly monitoring volcanoes, and such a need for clean, renewable energy?

  3. Modeling the Daly Gap: The Influence of Latent Heat Production in Controlling Magma Extraction and Eruption

    Science.gov (United States)

    Nelson, B. K.; Ghiorso, M. S.; Bachmann, O.; Dufek, J.

    2011-12-01

    A century-old issue in volcanology is the origin of the gap in chemical compositions observed in magmatic series on ocean islands and arcs - the "Daly Gap". If the gap forms during differentiation from a mafic parent, models that predict the dynamics of magma extraction as a function of chemical composition must simulate a process that results in volumetrically biased, bimodal compositions of erupted magmas. The probability of magma extraction is controlled by magma dynamical processes, which have a complex response to magmatic heat evolution. Heat loss from the magmatic system is far from a simple, monotonic function of time. It is modified by the crystallization sequence, chamber margin heat flux, and is buffered by latent heat production. We use chemical and thermal calculations of MELTS (Ghiorso & Sack, 1995) as input to the physical model of QUANTUM (Dufek & Bachmann, 2010) to predict crystallinity windows of most probable magma extraction. We modeled two case studies: volcanism on Tenerife, Canary Islands, and the Campanian Ignimbrite (CI) of Campi Flegrei, Italy. Both preserve a basanitic to phonolitic lineage and have comparable total alkali concentrations; however, CI has high and Tenerife has low K2O/Na2O. Modeled thermal histories of differentiation for the two sequences contrast strongly. In Tenerife, the rate of latent heat production is almost always greater than sensible heat production, with spikes in the ratio of latent to sensible heats of up to 40 associated with the appearance of Fe-Ti oxides at near 50% crystallization. This punctuated heat production must cause magma temperature change to stall or slow in time. The extended time spent at ≈50% crystallinity, associated with dynamical processes that enhance melt extraction near 50% crystallinity, suggests the magma composition at this interval should be common. In Tenerife, the modeled composition coincides with that of the first peak in the bimodal frequency-composition distribution. In our

  4. Ocean Thermal Extractable Energy Visualization

    Energy Technology Data Exchange (ETDEWEB)

    Ascari, Matthew [Lockheed Martin Corporation, Bethesda, MD (United States)

    2012-10-28

    The Ocean Thermal Extractable Energy Visualization (OTEEV) project focuses on assessing the Maximum Practicably Extractable Energy (MPEE) from the world’s ocean thermal resources. MPEE is defined as being sustainable and technically feasible, given today’s state-of-the-art ocean energy technology. Under this project the OTEEV team developed a comprehensive Geospatial Information System (GIS) dataset and software tool, and used the tool to provide a meaningful assessment of MPEE from the global and domestic U.S. ocean thermal resources.

  5. Phoenix I energy extraction experiment

    International Nuclear Information System (INIS)

    Hoffman, J.M.; Patterson, E.L.; Tisone, G.C.; Moreno, J.B.

    1980-07-01

    Energy extraction experiments are reported for the Phoenix I amplifier driven by a discharge-initiated oscillator-preamplifier system operating on mixtures of either SF 6 -HI or SF 6 -C 2 H 6 and an electron-beam-initiated intermediate amplifer (lambda-3) fueled with H 2 and F 2 mixtures. When the oscillator-preamplifier system operated with mixtures of SF 6 -HI the input spectrum to the Phoenix I amplifier contained approx. 28 P-branch vibrational-rotational lines which were almost identical to the input spectrum from the H 2 -F 2 fueled oscillator. In this case the energy extraction measurements were essentially the same as the results obtained with the spectrum produced using H 2 and F 2 mixtures. For an input intensity of 10 7 W/cm 2 , 170 J were extracted from the amplifier. With the SF 6 -C 2 H 6 spectrum, extraction was only obtained from the first three excited vibrational levels. This result indicates that most of the energy in the amplifier could be extracted on the first three excited vibrational levels. It is shown that the extraction results can be fit with a simple two level model. The radius of curvature of the beam was estimated using a lateral shearing interferometer. It was found that the Phoenix I amplifier altered the radius of curvature

  6. Coupling Thermal and Chemical Signatures of Crustal Magma Bodies: Energy-Constrained Eruption, Recharge, Assimilation, and Fractional Crystallization (E'RAχFC)

    Science.gov (United States)

    Bohrson, W. A.; Spera, F. J.

    2004-12-01

    Energy-Constrained Eruption, Recharge, Assimilation and Fractional Crystallization (E'RAχFC) tracks the evolution of an open-system magmatic system by coupling conservation equations governing energy, mass and species (isotopes and trace elements). By linking the compositional characteristics of a composite magmatic system (host magma, recharge magma, wallrock, eruptive reservoir) to its mass and energy fluxes, predictions can be made about the chemical evolution of systems characterized by distinct compositional and thermal characteristics. An interesting application of E'RAχFC involves documenting the influence distinct thermal regimes have on the chemical evolution of magmatic systems. Heat transfer between a magma-country rock system at epizonal depths can be viewed as a conjugate heat transfer problem in which the average country rock-magma boundary temperature, Tb, is governed by the relative vigor of hydrothermal convection in the country rock vs. magma convection. For cases where hydrothermal circulation is vigorous and magmatic heat is efficiently transported away from the boundary, contact aureole temperatures (~Tb) are low. In cases where magmatic heat can not be efficiently transported away from the boundary and hydrothermal cells are absent or poorly developed, Tb is relatively high. Simultaneous solution of the differential equations governing momentum and energy conservation and continuity for the coupled hydrothermal-magmatic conjugate heat transfer system enables calculation of the characteristic timescale for EC-RAFC evolution and development of hydrothermal deposits as a function of material and medium properties, sizes of systems and relative efficiency of hydrothermal vs. magmatic heat transfer. Characteristic timescales lie in the range 102-106 yr depending on system size, magma properties and permeability among other parameters. In E'RAχFC, Tb is approximated by the user-defined equilibration temperature, Teq, which is the temperature at

  7. Extracting Minerals from Seawater: An Energy Analysis

    Directory of Open Access Journals (Sweden)

    Ugo Bardi

    2010-04-01

    Full Text Available The concept of recovering minerals from seawater has been proposed as a way of counteracting the gradual depletion of conventional mineral ores. Seawater contains large amounts of dissolved ions and the four most concentrated metal ones (Na, Mg, Ca, K are being commercially extracted today. However, all the other metal ions exist at much lower concentrations. This paper reports an estimate of the feasibility of the extraction of these metal ions on the basis of the energy needed. In most cases, the result is that extraction in amounts comparable to the present production from land mines would be impossible because of the very large amount of energy needed. This conclusion holds also for uranium as fuel for the present generation of nuclear fission plants. Nevertheless, in a few cases, mainly lithium, extraction from seawater could provide amounts of metals sufficient for closing the cycle of metal use in the economy, provided that an increased level of recycling can be attained.

  8. Lunar magma transport phenomena

    Science.gov (United States)

    Spera, Frank J.

    1992-01-01

    An outline of magma transport theory relevant to the evolution of a possible Lunar Magma Ocean and the origin and transport history of the later phase of mare basaltic volcanism is presented. A simple model is proposed to evaluate the extent of fractionation as magma traverses the cold lunar lithosphere. If Apollo green glasses are primitive and have not undergone significant fractionation en route to the surface, then mean ascent rates of 10 m/s and cracks of widths greater than 40 m are indicated. Lunar tephra and vesiculated basalts suggest that a volatile component plays a role in eruption dynamics. The predominant vapor species appear to be CO CO2, and COS. Near the lunar surface, the vapor fraction expands enormously and vapor internal energy is converted to mixture kinetic energy with the concomitant high-speed ejection of vapor and pyroclasts to form lunary fire fountain deposits such as the Apollo 17 orange and black glasses and Apollo 15 green glass.

  9. Wave energy extraction using decommisioned ships

    DEFF Research Database (Denmark)

    Mansour, A.E.; Pedersen, Preben Terndrup; Paik, J.K.

    2013-01-01

    is to tune the ship to have rigid body resonance, or close to it, and resist that motion to absorb power. A hydraulic ramp connected to an accumulator feeding a hydraulic motor that generates power is one possibility. Several other energy extraction mechanisms such as turbines connected to oscillating water...

  10. Enhancing radiative energy transfer through thermal extraction

    Science.gov (United States)

    Tan, Yixuan; Liu, Baoan; Shen, Sheng; Yu, Zongfu

    2016-06-01

    Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics. Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal

  11. The Magma Chamber Simulator: Modeling the Impact of Wall Rock Composition on Mafic Magmas during Assimilation-Fractional Crystallization

    Science.gov (United States)

    Creamer, J. B.; Spera, F. J.; Bohrson, W. A.; Ghiorso, M. S.

    2012-12-01

    Although stoichiometric titration is often used to model the process of concurrent Assimilation and Fractional Crystallization (AFC) within a compositionally evolving magma body, a more complete treatment of the problem involves simultaneous and self-consistent determination of stable phase relationships and separately evolving temperatures of both Magma (M) and Wall Rock (WR) that interact as a composite M-WR system. Here we present results of M-WR systems undergoing AFC forward modeled with the Magma Chamber Simulator (MCS), which uses the phase modeling capabilities of MELTS (Ghiorso & Sack 1995) as the thermodynamic basis. Simulations begin with one of a variety of mafic magmas (e.g. HAB, MORB, AOB) intruding a set mass of Wall Rock (e.g. lherzolite, gabbro, diorite, granite, metapelite), and heat is exchanged as the M-WR system proceeds towards thermal equilibrium. Depending on initial conditions, the early part of the evolution can involve closed system FC while the WR heats up. The WR behaves as a closed system until it is heated beyond the solidus to critical limit for melt fraction extraction (fc), ranging between 0.08 and 0.12 depending on WR characteristics including composition and, rheology and stress field. Once fc is exceeded, a portion of the anatectic liquid is assimilated into the Magma. The MCS simultaneously calculates mass and composition of the mineral assemblage (Magma cumulates and WR residue) and melt (anatectic and Magma) at each T along the equilibration trajectory. Sensible and latent heat lost or gained plus mass gained by the Magma are accounted for by the MCS via governing Energy Constrained- Recharge Assimilation Fractional Crystallization (EC-RAFC) equations. In a comparison of two representative MCS results, consider a granitic WR intruded by HAB melt (51 wt. % SiO2) at liquidus T in shallow crust (0.1 GPa) with a WR/M ratio of 1.25, fc of 0.1 and a QFM oxygen buffer. In the first example, the WR begins at a temperature of 100o

  12. Maximal energy extraction under discrete diffusive exchange

    Energy Technology Data Exchange (ETDEWEB)

    Hay, M. J., E-mail: hay@princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Schiff, J. [Department of Mathematics, Bar-Ilan University, Ramat Gan 52900 (Israel); Fisch, N. J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2015-10-15

    Waves propagating through a bounded plasma can rearrange the densities of states in the six-dimensional velocity-configuration phase space. Depending on the rearrangement, the wave energy can either increase or decrease, with the difference taken up by the total plasma energy. In the case where the rearrangement is diffusive, only certain plasma states can be reached. It turns out that the set of reachable states through such diffusive rearrangements has been described in very different contexts. Building upon those descriptions, and making use of the fact that the plasma energy is a linear functional of the state densities, the maximal extractable energy under diffusive rearrangement can then be addressed through linear programming.

  13. Enhancing radiative energy transfer through thermal extraction

    Directory of Open Access Journals (Sweden)

    Tan Yixuan

    2016-06-01

    Full Text Available Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a. In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics.

  14. Applying Fractal Dimensions and Energy-Budget Analysis to Characterize Fracturing Processes During Magma Migration and Eruption: 2011-2012 El Hierro (Canary Islands) Submarine Eruption

    Science.gov (United States)

    López, Carmen; Martí, Joan; Abella, Rafael; Tarraga, Marta

    2014-07-01

    The impossibility of observing magma migration inside the crust obliges us to rely on geophysical data and mathematical modelling to interpret precursors and to forecast volcanic eruptions. Of the geophysical signals that may be recorded before and during an eruption, deformation and seismicity are two of the most relevant as they are directly related to its dynamic. The final phase of the unrest episode that preceded the 2011-2012 eruption on El Hierro (Canary Islands) was characterized by local and accelerated deformation and seismic energy release indicating an increasing fracturing and a migration of the magma. Application of time varying fractal analysis to the seismic data and the characterization of the seismicity pattern and the strain and the stress rates allow us to identify different stages in the source mechanism and to infer the geometry of the path used by the magma and associated fluids to reach the Earth's surface. The results obtained illustrate the relevance of such studies to understanding volcanic unrest and the causes that govern the initiation of volcanic eruptions.

  15. Comparative Magma Oceanography

    Science.gov (United States)

    Jones, J. H.

    1999-01-01

    and, perhaps, mostly molten. The Giant Impact hypothesis for the origin of the Moon offers a tremendous input of thermal energy and the same could be true for core formation. And current solar system models favor the formation of a limited number of large (about 1000 km) planetesimals that, upon accreting to Earth, would cause great heating, being lesser versions of the Giant Impact. Several lines of geochemical evidence do not favor this hot early Earth scenario. (i) Terrestrial man-tle xenoliths are sometimes nearly chondritic in their major element compositions, suggesting that these rocks have never been much molten. Large degrees of partial melting probably promote differentiation rather than homogenization. (ii) Unlike the case of Mars, the continental crust probably did not form as a highly fractionated residual liquid from a magma ocean (about 99% crystallization), but, rather, formed in multiple steps. [The simplest model for the formation of continental crust is complicated: (a) about 10% melting of a primitive mantle, making basalt; (b) hydrothermal alteration of that basalt, converting it to greenstone; and (c) 10% partial melting of that greenstone, producing tonalite.] This model is reinforced by the recent observation from old (about 4.1 b.y.) zircons that the early crust formed from an undepleted mantle having a chondritic Lu/Hf ratio. (iii) If the mantle were once differentiated by a magma ocean, the mantle xenolith suite requires that it subsequently be homogenized. The Os isotopic compositions of fertile spinel lherzolites place constraints on the timing of that homogenization. The Os isotopic composition of spinel lherzolites approaches that of chondrites and correlates with elements such as Lu and Al. As Lu and Al concentrations approach those of the primitive mantle, Os isotopic compositions approach chondritic. The Re and Os in these xenoliths were probably added as a late veneer. Thus, the mantle that received the late veneer must have been

  16. Modeling and prediction of extraction profile for microwave-assisted extraction based on absorbed microwave energy.

    Science.gov (United States)

    Chan, Chung-Hung; Yusoff, Rozita; Ngoh, Gek-Cheng

    2013-09-01

    A modeling technique based on absorbed microwave energy was proposed to model microwave-assisted extraction (MAE) of antioxidant compounds from cocoa (Theobroma cacao L.) leaves. By adapting suitable extraction model at the basis of microwave energy absorbed during extraction, the model can be developed to predict extraction profile of MAE at various microwave irradiation power (100-600 W) and solvent loading (100-300 ml). Verification with experimental data confirmed that the prediction was accurate in capturing the extraction profile of MAE (R-square value greater than 0.87). Besides, the predicted yields from the model showed good agreement with the experimental results with less than 10% deviation observed. Furthermore, suitable extraction times to ensure high extraction yield at various MAE conditions can be estimated based on absorbed microwave energy. The estimation is feasible as more than 85% of active compounds can be extracted when compared with the conventional extraction technique. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Batteries for efficient energy extraction from a water salinity difference.

    Science.gov (United States)

    La Mantia, Fabio; Pasta, Mauro; Deshazer, Heather D; Logan, Bruce E; Cui, Yi

    2011-04-13

    The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery", which can extract and store it as useful electrochemical energy. The battery, containing a Na(2-x)Mn(5)O(10) nanorod electrode, was shown to extract energy from real seawater and river water and can be applied to a variety of salt waters. We demonstrated energy extraction efficiencies of up to 74%. Considering the flow rate of river water into oceans as the limiting factor, the renewable energy production could potentially reach 2 TW, or ∼13% of the current world energy consumption. The mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future.

  18. Batteries for Efficient Energy Extraction from a Water Salinity Difference

    KAUST Repository

    La Mantia, Fabio

    2011-04-13

    The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery", which can extract and store it as useful electrochemical energy. The battery, containing a Na2-xMn 5O10 nanorod electrode, was shown to extract energy from real seawater and river water and can be applied to a variety of salt waters. We demonstrated energy extraction efficiencies of up to 74%. Considering the flow rate of river water into oceans as the limiting factor, the renewable energy production could potentially reach 2 TW, or ∼13% of the current world energy consumption. The mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future. © 2011 American Chemical Society.

  19. Batteries for Efficient Energy Extraction from a Water Salinity Difference

    KAUST Repository

    La Mantia, Fabio; Pasta, Mauro; Deshazer, Heather D.; Logan, Bruce E.; Cui, Yi

    2011-01-01

    The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery

  20. The Meaning of "Magma"

    Science.gov (United States)

    Bartley, J. M.; Glazner, A. F.; Coleman, D. S.

    2016-12-01

    Magma is a fundamental constituent of the Earth, and its properties, origin, evolution, and significance bear on issues ranging from volcanic hazards to planetary evolution. Unfortunately, published usages indicate that the term "magma" means distinctly different things to different people and this can lead to miscommunication among Earth scientists and between scientists and the public. Erupting lava clearly is magma; the question is whether partially molten rock imaged at depth and too crystal-rich to flow should also be called magma. At crystal fractions > 50%, flow can only occur via crystal deformation and solution-reprecipitation. As the solid fraction increases to 90% or more, the material becomes a welded crystal framework with melt in dispersed pores and/or along grain boundaries. Seismic images commonly describe such volumes of a few % melt as magma, yet the rheological differences between melt-rich and melt-poor materials make it vital not to confuse a large rock volume that contains a small melt fraction with melt-rich material. To ensure this, we suggest that "magma" be reserved for melt-rich materials that undergo bulk fluid flow on timescales consonant with volcanic eruptions. Other terms should be used for more crystal-rich and largely immobile partially molten rock (e.g., "crystal mush," "rigid sponge"). The distinction is imprecise but useful. For the press, the public, and even earth scientists who do not study magmatic systems, "magma" conjures up flowing lava; reports of a large "magma" body that contains a few percent melt can engender the mistaken perception of a vast amount of eruptible magma. For researchers, physical processes like crystal settling are commonly invoked to account for features in plutonic rocks, but many such processes are only possible in melt-rich materials.

  1. Extraction study on uranyl nitrate for energy applications

    Science.gov (United States)

    Giri, R.; Nath, G.

    2017-07-01

    Due to the ever-growing demand of energy nuclear reactor materials and the nuclear energy are now considered to be the most critical materials and source of energy for future era. Deposition of nuclear wastes in different industry, nuclear power sector are very much toxic in open environment which are hazardous to living being. There are different methods for extraction and reprocessing of these materials which are cost effective and tedious process. Ultrasonic assisted solvent extraction process is a most efficient and economical way for extraction of such type materials. The presence of third phase in mixing of extractants-diluent pair with aqueous phase imposes the problems in extraction of nuclear reactor materials. The appropriate solvent mixture in proper concentration is an important step in the solvent extraction process. Study of thermo-physical properties helps in selecting an optimum blend for extraction process. In the present work, the extraction of uranium with the binary mixture of Methyl Ethyl Ketone (MEK) and Kerosene was investigated and discussed with the variation of ultrasonic frequency for different temperatures. The result shows that the low frequency and low temperature is suitable environment for extraction. The extraction of uranium by this method is found to be a better result for extraction study in laboratory scale as well as industrial sector.

  2. Energy efficient trace removal by extractive distillation

    NARCIS (Netherlands)

    Jongmans, M.T.G.

    2012-01-01

    Separation processes contribute for about 40–70 % to the total energy requirements of the chemical process industry. Especially when trace removal is required to manufacture high purity products, traditional separation technologies become extremely expensive and are not providing satisfying

  3. The crustal magma storage system of Volcán Quizapu, Chile, and the effects of magma mixing on magma diversity

    Science.gov (United States)

    Bergantz, George W.; Cooper, Kari M.; Hildreth, Edward; Ruprecht, Phillipp

    2012-01-01

    Crystal zoning as well as temperature and pressure estimates from phenocryst phase equilibria are used to constrain the architecture of the intermediate-sized magmatic system (some tens of km3) of Volcán Quizapu, Chile, and to document the textural and compositional effects of magma mixing. In contrast to most arc magma systems, where multiple episodes of open-system behavior obscure the evidence of major magma chamber events (e.g. melt extraction, magma mixing), the Quizapu magma system shows limited petrographic complexity in two large historical eruptions (1846–1847 and 1932) that have contrasting eruptive styles. Quizapu magmas and peripheral mafic magmas exhibit a simple binary mixing relationship. At the mafic end, basaltic andesite to andesite recharge magmas complement the record from peripheral cones and show the same limited range of compositions. The silicic end-member composition is almost identical in both eruptions of Quizapu. The effusive 1846–1847 eruption records significant mixing between the mafic and silicic end-members, resulting in hybridized andesites and mingled dacites. These two compositionally simple eruptions at Volcán Quizapu present a rare opportunity to isolate particular aspects of magma evolution—formation of homogeneous dacite magma and late-stage magma mixing—from other magma chamber processes. Crystal zoning, trace element compositions, and crystal-size distributions provide evidence for spatial separation of the mafic and silicic magmas. Dacite-derived plagioclase phenocrysts (i.e. An25–40) show a narrow range in composition and limited zonation, suggesting growth from a compositionally restricted melt. Dacite-derived amphibole phenocrysts show similar restricted compositions and furthermore constrain, together with more mafic amphibole phenocrysts, the architecture of the magmatic system at Volcán Quizapu to be compositionally and thermally zoned, in which an andesitic mush is overlain by a homogeneous dacitic

  4. Phoenix II energy extraction and angular multiplexing experiments

    International Nuclear Information System (INIS)

    Hoffman, J.M.; Hays, G.N.

    1981-08-01

    The energy extraction efficiency as a function of input intensity has been determined from a large-volume HF amplifier. For an input intensity of 4 x 10 6 W/cm 2 , 1080 Joules was extracted from the amplifier. This corresponded to an energy extraction efficiency of 0.90. At the highest H 2 /F 2 /O 2 pressures used, 1700 Joules was obtained from this system when used in an oscillator configuration. These results also show evidence that energy extraction at low input intensities in large-volume HF amplifiers is strongly influenced by parasitic oscillations. The results also indicate that, for a long-pulse HF amplifier (60-nsec electron beam), the timing between the amplifier and oscillator to achieve optimum operating conditions is not very critical. This same amplifier, used in conjunction with a short-pulse, good-beam-quality oscillator-preamplifier chain, has also been used to evaluate pulse compression using angular multiplexing. Using two sequential 24-nsec pulses, the essential elements of angular multiplexing have been evaluated as a function of interpulse separation time. Included are energy extraction efficiency, overall temporal pulse distortion, leading-edge contrast-ratio distortion, and suppression of amplified spontaneous emission relative to a single, long-duration input pulse. For appropriate interpulse delay time, we show that distortionless amplification is possible with energy-extraction efficiency the same as is obtained using a single input beam having a pulse width equal to the duration of the amplifier gain

  5. On the hydrophilicity of electrodes for capacitive energy extraction

    International Nuclear Information System (INIS)

    Lian, Cheng; East China University of Science and Technology, Shanghai; Kong, Xian; Tsinghua University, Beijing; Liu, Honglai; Wu, Jianzhong

    2016-01-01

    The so-called Capmix technique for energy extraction is based on the cyclic expansion of electrical double layers to harvest dissipative energy arising from the salinity difference between freshwater and seawater. Its optimal performance requires a careful selection of the electrical potentials for the charging and discharging processes, which must be matched with the pore characteristics of the electrode materials. While a number of recent studies have examined the effects of the electrode pore size and geometry on the capacitive energy extraction processes, there is little knowledge on how the surface properties of the electrodes affect the thermodynamic efficiency. In this paper, we investigate the Capmix processes using the classical density functional theory for a realistic model of electrolyte solutions. The theoretical predictions allow us to identify optimal operation parameters for capacitive energy extraction with porous electrodes of different surface hydrophobicity. Finally, in agreement with recent experiments, we find that the thermodynamic efficiency can be much improved by using most hydrophilic electrodes.

  6. Assessment of proposed electromagnetic quantum vacuum energy extraction methods

    OpenAIRE

    Moddel, Garret

    2009-01-01

    In research articles and patents several methods have been proposed for the extraction of zero-point energy from the vacuum. None has been reliably demonstrated, but the proposals remain largely unchallenged. In this paper the feasibility of these methods is assessed in terms of underlying thermodynamics principles of equilibrium, detailed balance, and conservation laws. The methods are separated into three classes: nonlinear processing of the zero-point field, mechanical extraction using Cas...

  7. Wave energy extraction by coupled resonant absorbers.

    Science.gov (United States)

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment.

  8. Thermodynamics of energy extraction from fractured hot dry rock

    Energy Technology Data Exchange (ETDEWEB)

    Lim, J S; Bejan, A [Duke Univ., Durham, NC (United States). Dept. of Mechanical Engineering and Materials Science; Kim, J H [Electric Power Research Inst., Palo Alto, CA (United States)

    1992-03-01

    It has been proposed to extract energy from the subterranean hot dry rock bed (HDR) by creating one or more narrow fractures in the rock and circulating cold water through the fractures. In time, the temperature of the rock region surrounding the crack drops under the influence of time-dependent conduction. This study presents the most basic thermodynamic aspects (first law and second law) of the HDR energy extraction process. It shows which parameters most influence the amount of useful energy (exergy) extracted from the HDR reservoir over a fixed time interval. For example, the water flow rate can be selected optimally in order to maximize the delivery of exergy over the lifetime of the HDR system. (author).

  9. Coherent Wave Measurement Buoy Arrays to Support Wave Energy Extraction

    Science.gov (United States)

    Spada, F.; Chang, G.; Jones, C.; Janssen, T. T.; Barney, P.; Roberts, J.

    2016-02-01

    Wave energy is the most abundant form of hydrokinetic energy in the United States and wave energy converters (WECs) are being developed to extract the maximum possible power from the prevailing wave climate. However, maximum wave energy capture is currently limited by the narrow banded frequency response of WECs as well as extended protective shutdown requirements during periods of large waves. These limitations must be overcome in order to maximize energy extraction, thus significantly decreasing the cost of wave energy and making it a viable energy source. Techno-economic studies of several WEC devices have shown significant potential to improve wave energy capture efficiency through operational control strategies that incorporate real-time information about local surface wave motions. Integral Consulting Inc., with ARPA-E support, is partnering with Sandia National Laboratories and Spoondrift LLC to develop a coherent array of wave-measuring devices to relay and enable the prediction of wave-resolved surface dynamics at a WEC location ahead of real time. This capability will provide necessary information to optimize power production of WECs through control strategies, thereby allowing for a single WEC design to perform more effectively across a wide range of wave environments. The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000514.

  10. From Extraction to Renewal: A Global Campaign for Healthy Energy.

    Science.gov (United States)

    Wang, Jennifer S; Euripidou, Rico; Armstrong, Fiona; Jensen, Génon K; Karliner, Josh; Guinto, Renzo R; Zhao, Ang; Narayanan, Divya; Orris, Peter

    2016-02-01

    A global movement is emerging in the health sector to engage in discourse and advocacy on the health impacts and health costs of energy choices--specifically the health harms of extractive, climate-disrupting energy sources such as coal and gas. Individuals and organizations in the health sector have begun to address climate and energy issues at multiple levels of engagement, including with others in the health sector, with pollution-affected communities, with policy makers, and with the media. We present recent examples of health sector advocacy and leadership on the health impacts of energy choices and opportunities for broadening and deepening the movement. © The Author(s) 2016.

  11. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  12. Capacitive technology for energy extraction from chemical potential differences

    NARCIS (Netherlands)

    Bastos Sales, B.

    2013-01-01

    This thesis introduces the principle of Capacitive energy extraction based on Donnan Potential (CDP) to exploit salinity gradients. It also shows the fundamental characterization and improvements of CDP. An alternative application of this technology aimed at thermal gradients was tested.

  13. Cyclotrons with fast variable and/or multiple energy extraction

    Directory of Open Access Journals (Sweden)

    C. Baumgarten

    2013-10-01

    Full Text Available We discuss the possibility in principle of stripping extraction in combination with reverse bends in isochronous separate-sector cyclotrons (and/or fixed field alternating gradient accelerators. If one uses reverse bends between the sectors (instead of or in combination with drifts and places stripper foils at the sector exit edges, the stripped beam has a reduced bending radius and it should be able to leave the cyclotron within the range of the valley—even if the beam is stripped at less than full energy. We are especially interested in stripping of H_{2}^{+}, as it doubles the charge to mass ratio of the ions. However the method could be applied to other ions or ionized molecules as well. For the production of proton beams by stripping extraction of an H_{2}^{+} beam, we discuss possible designs for three types of machines: First, a low-energy cyclotron for the simultaneous production of several beams at multiple energies—for instance 15, 30, and 70 MeV—thus allowing beam delivery on several isotope production targets. In this case it can be an advantage to have a strong energy dependence of the direction of the extracted beam. Second, we consider a fast variable-energy proton machine for cancer therapy that should allow extraction (of the complete beam at all energies in the range of about 70 MeV to about 250 MeV into the same beam line. Third, we consider a high-intensity high-energy machine, where the main design goals are extraction with low losses, low activation of components, and high reliability. Especially if such a machine is considered for an accelerator driven system (ADS, this extraction mechanism has advantages: Beam trips by the failure of electrostatic elements could be avoided and the turn separation would be less critical, which allows operation at lower main cavity voltages. This would in turn reduce the number of rf trips. The price that has to be paid for these advantages is an increase in size and/or field

  14. The Surtsey Magma Series.

    Science.gov (United States)

    Schipper, C Ian; Jakobsson, Sveinn P; White, James D L; Michael Palin, J; Bush-Marcinowski, Tim

    2015-06-26

    The volcanic island of Surtsey (Vestmannaeyjar, Iceland) is the product of a 3.5-year-long eruption that began in November 1963. Observations of magma-water interaction during pyroclastic episodes made Surtsey the type example of shallow-to-emergent phreatomagmatic eruptions. Here, in part to mark the 50(th) anniversary of this canonical eruption, we present previously unpublished major-element whole-rock compositions, and new major and trace-element compositions of sideromelane glasses in tephra collected by observers and retrieved from the 1979 drill core. Compositions became progressively more primitive as the eruption progressed, with abrupt changes corresponding to shifts between the eruption's four edifices. Trace-element ratios indicate that the chemical variation is best explained by mixing of different proportions of depleted ridge-like basalt, with ponded, enriched alkalic basalt similar to that of Iceland's Eastern Volcanic Zone; however, the systematic offset of Surtsey compositions to lower Nb/Zr than other Vestmannaeyjar lavas indicates that these mixing end members are as-yet poorly contained by compositions in the literature. As the southwestern-most volcano in the Vestmannaeyjar, the geochemistry of the Surtsey Magma Series exemplifies processes occurring within ephemeral magma bodies on the extreme leading edge of a propagating off-axis rift in the vicinity of the Iceland plume.

  15. Pressure waves in a supersaturated bubbly magma

    Science.gov (United States)

    Kurzon, I.; Lyakhovsky, V.; Navon, O.; Chouet, B.

    2011-01-01

    We study the interaction of acoustic pressure waves with an expanding bubbly magma. The expansion of magma is the result of bubble growth during or following magma decompression and leads to two competing processes that affect pressure waves. On the one hand, growth in vesicularity leads to increased damping and decreased wave amplitudes, and on the other hand, a decrease in the effective bulk modulus of the bubbly mixture reduces wave velocity, which in turn, reduces damping and may lead to wave amplification. The additional acoustic energy originates from the chemical energy released during bubble growth. We examine this phenomenon analytically to identify conditions under which amplification of pressure waves is possible. These conditions are further examined numerically to shed light on the frequency and phase dependencies in relation to the interaction of waves and growing bubbles. Amplification is possible at low frequencies and when the growth rate of bubbles reaches an optimum value for which the wave velocity decreases sufficiently to overcome the increased damping of the vesicular material. We examine two amplification phase-dependent effects: (1) a tensile-phase effect in which the inserted wave adds to the process of bubble growth, utilizing the energy associated with the gas overpressure in the bubble and therefore converting a large proportion of this energy into additional acoustic energy, and (2) a compressive-phase effect in which the pressure wave works against the growing bubbles and a large amount of its acoustic energy is dissipated during the first cycle, but later enough energy is gained to amplify the second cycle. These two effects provide additional new possible mechanisms for the amplification phase seen in Long-Period (LP) and Very-Long-Period (VLP) seismic signals originating in magma-filled cracks.

  16. Energy quality and energy surplus in the extraction of fossil fuels in the US

    International Nuclear Information System (INIS)

    Cleveland, C.J.

    1992-01-01

    The goal of net energy analysis is to assess the amount of useful energy delivered by an energy system, net of the energy costs of delivery. The standard technique of aggregating energy inputs and outputs by their thermal equivalents diminish the ability of energy analysis to achieve the goal because different types of energy have different abilities to do work per heat equivalent. This paper describes physical and economic methods of calculating energy quality, and incorporate economic estimates of quality in the analysis of the energy return on investment (EROI) for the extraction of coal and petroleum resources in the US from 1954 to 1987. EROI is the ratio of energy delivered to energy used in the delivery process. The quality- adjusted EROI is used to answer the following questions: (1) are coal and petroleum resources becoming more scarce in the US? (2) is society's capability of doing useful economic work changing? and (3) is society's allocation of energy between the extraction of coal and petroleum optimal? The results indicate that petroleum and coal become more scarce in the 1970s, although the degree of scarcity depends on the type of quality factor used. The quality-adjusted EROI shed light on the coal-petroleum paradox: when energy inputs and outputs are measured in thermal equivalents, coal extraction has a much larger EROI than petroleum. The adjustment for energy quality reduces substantially the difference between the two fuels. The results also suggest that when corrections are made for energy quality, society's allocation of energy between coal and petroleum extraction meets the efficiency criteria described by neoclassical and biophysical economists. 3 figs., 1 tab., 40 refs

  17. Regulatory, Land Ownership, and Water Availability Factors for a Magma Well: Long Valley Caldera and Coso Hot Springs, California

    Energy Technology Data Exchange (ETDEWEB)

    Blackett, Robert

    1985-09-01

    The U.S. Department of Energy is currently engaged in a program to demonstrate the engineering feasibility of extracting thermal energy from high-level molten magma bodies. The program is being carried out under the direction of Sandia National Laboratories where a number of individual projects support the overall program. The existing program elements include (1) high-temperature materials compatibility testing; (2) studies of properties of melts of various compositions; and (3) the investigation of the economics of a magma energy extraction system. Another element of the program is being conducted with the cooperation of the U.S. Geological Survey, and involves locating and outlining magma bodies at selected sites using various geophysical techniques. The ultimate goal here will be to define the limits of a magma body as a drilling target. During an earlier phase of the program, more than twenty candidate study sites considered were evaluated based upon: (1) the likelihood of the presence of a shallow magma chamber, (2) the accessibility of the site, and (3) physical and institutional constraints associated with each site with respect to performing long-term experiments. From these early phase activities, the number of candidate sites were eventually narrowed to just 2. The sites currently under consideration are Coso Hot Springs and the Long Valley caldera (Figure 1). This report describes certain attributes of these sites in order to help identify potential problems related to: (1) state and federal regulations pertaining to geothermal development; (2) land ownership; and (3) water resource availability. The information sources used in this study were mainly maps, publications, and informative documents gathered from the California Division of Oil and Gas and the U.S. Department of the Interior. Environmental studies completed for the entire Long Valley caldera study area, and for portions of the Coso Hot Springs study area were also used for reference.

  18. Maximum wind energy extraction strategies using power electronic converters

    Science.gov (United States)

    Wang, Quincy Qing

    2003-10-01

    This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through

  19. Short-circuiting magma differentiation from basalt straight to rhyolite?

    Science.gov (United States)

    Ruprecht, P.; Winslow, H.

    2017-12-01

    Silicic magmas are the product of varying degrees of crystal fractionation and crustal assimilation/melting. Both processes lead to differentiation that is step-wise rather than continuous for example during melt separation from a crystal mush (Dufek and Bachmann, 2010). However, differentiation is rarely efficient enough to evolve directly from a basaltic to a rhyolitic magma. At Volcán Puyehue-Cordón Caulle, Chile, the magma series is dominated by crystal fractionation where mixing trends between primitive and felsic end members in the bulk rock compositions are almost absent (e.g. P, FeO, TiO2 vs. SiO2). How effective fraction is in this magmatic system is not well-known. The 2011-12 eruption at Cordón Caulle provides new constraints that rhyolitic melts may be derived directly from a basaltic mush. Minor, but ubiquitous mafic, crystal-rich enclaves co-erupted with the predominantly rhyolitic near-aphyric magma. These enclaves are among the most primitive compositions erupted at Puyehue-Cordón Caulle and geochemically resemble closely basaltic magmas that are >10 ka old (Singer et al. 2008) and that have been identified as a parental tholeiitic mantle-derived magma (Schmidt and Jagoutz, 2017) for the Southern Andean Volcanic Zone. The vesiculated nature, the presence of a microlite-rich groundmass, and a lack of a Eu anomaly in these encalves suggest that they represent recharge magma/mush rather than sub-solidus cumulates and therefore have potentially a direct petrogenetic link to the erupted rhyolites. Our results indicate that under some conditions crystal fractionation can be very effective and the presence of rhyolitic magmas does not require an extensive polybaric plumbing system. Instead, primitive mantle-derived magmas source directly evolved magmas. In the case, of the magma system beneath Puyehue-Cordón Caulle, which had three historic rhyolitic eruptions (1921-22, 1960, 2011-12) these results raise the question whether rhyolite magma extraction

  20. Javanese Character Feature Extraction Based on Shape Energy

    Directory of Open Access Journals (Sweden)

    Galih Hendra Wibowo

    2017-07-01

    Full Text Available Javanese character is one of Indonesia's noble culture, especially in Java. However, the number of Javanese people who are able to read the letter has decreased so that there need to be conservation efforts in the form of a system that is able to recognize the characters. One solution to these problem lies in Optical Character Recognition (OCR studies, where one of its heaviest points lies in feature extraction which is to distinguish each character. Shape Energy is one of feature extraction method with the basic idea of how the character can be distinguished simply through its skeleton. Based on the basic idea, then the development of feature extraction is done based on its components to produce an angular histogram with various variations of multiples angle. Furthermore, the performance test of this method and its basic method is performed in Javanese character dataset, which has been obtained from various images, is 240 data with 19 labels by using K-Nearest Neighbors as its classification method. Performance values were obtained based on the accuracy which is generated through the Cross-Validation process of 80.83% in the angular histogram with an angle of 20 degrees, 23% better than Shape Energy. In addition, other test results show that this method is able to recognize rotated character with the lowest performance value of 86% at 180-degree rotation and the highest performance value of 96.97% at 90-degree rotation. It can be concluded that this method is able to improve the performance of Shape Energy in the form of recognition of Javanese characters as well as robust to the rotation.

  1. Superheat in magma oceans

    Science.gov (United States)

    Jakes, Petr

    1992-01-01

    The existence of 'totally molten' planets implies the existence of a superheat (excess of heat) in the magma reservoirs since the heat buffer (i.e., presence of crystals having high latent heat of fusion) does not exist in a large, completely molten reservoir. Any addition of impacting material results in increase of the temperature of the melt and under favorable circumstances heat is stored. The behavior of superheat melts is little understood; therefore, we experimentally examined properties and behavior of excess heat melts at atmospheric pressures and inert gas atmosphere. Highly siliceous melts (70 percent SiO2) were chosen for the experiments because of the possibility of quenching such melts into glasses, the slow rate of reaction in highly siliceous composition, and the fact that such melts are present in terrestrial impact craters and impact-generated glasses. Results from the investigation are presented.

  2. Analysis of synchronized charge extraction for piezoelectric energy harvesting

    International Nuclear Information System (INIS)

    Tang, Lihua; Yang, Yaowen

    2011-01-01

    In the past few years, various power conditioning circuits have been proposed to improve the efficiency of piezoelectric energy harvesting, among which the synchronized charge extraction (SCE) technique has been enthusiastically pursued. In the literature, the SCE technique is investigated based on the uncoupled or in-phase assumptions. The uncoupled assumption is only valid for weak electromechanical coupling and the in-phase assumption is not applicable for energy harvesting at off-resonance. In this paper, we derive an accurate analytical solution for the piezoelectric energy harvesting systems with the SCE technique. Based on this solution, we investigate the applicability of the SCE technique for different cases, i.e. the piezoelectric energy harvester (PEH) with various degrees of electromechanical coupling and the PEH excited at various frequencies. Circuit simulation is also conducted with an accurate circuit model derived for PEHs and the results validate the analytical outcomes. Both the accurate analytical solution and the circuit simulation show that the SCE technique cannot improve or even reduces the power output at resonance if the coupling of the PEH is not negligible. The SCE technique is found capable of significantly boosting the efficiency of energy harvesting only for the PEH vibrating at off-resonance frequencies or with weak coupling

  3. Energy extraction from atmospheric turbulence to improve flight vehicle performance

    Science.gov (United States)

    Patel, Chinmay Karsandas

    Small 'bird-sized' Unmanned Aerial Vehicles (UAVs) have now become practical due to technological advances in embedded electronics, miniature sensors and actuators, and propulsion systems. Birds are known to take advantage of wind currents to conserve energy and fly long distances without flapping their wings. This dissertation explores the possibility of improving the performance of small UAVs by extracting the energy available in atmospheric turbulence. An aircraft can gain energy from vertical gusts by increasing its lift in regions of updraft and reducing its lift in downdrafts - a concept that has been known for decades. Starting with a simple model of a glider flying through a sinusoidal gust, a parametric optimization approach is used to compute the minimum gust amplitude and optimal control input required for the glider to sustain flight without losing energy. For small UAVs using optimal control inputs, sinusoidal gusts with amplitude of 10--15% of the cruise speed are sufficient to keep the aircraft aloft. The method is then modified and extended to include random gusts that are representative of natural turbulence. A procedure to design optimal control laws for energy extraction from realistic gust profiles is developed using a Genetic Algorithm (GA). A feedback control law is designed to perform well over a variety of random gusts, and not be tailored for one particular gust. A small UAV flying in vertical turbulence is shown to obtain average energy savings of 35--40% with the use of a simple control law. The design procedure is also extended to determine optimal control laws for sinusoidal as well as turbulent lateral gusts. The theoretical work is complemented by experimental validation using a small autonomous UAV. The development of a lightweight autopilot and UAV platform is presented. Flight test results show that active control of the lift of an autonomous glider resulted in approximately 46% average energy savings compared to glides with fixed

  4. Numerical modeling of magma-repository interactions

    NARCIS (Netherlands)

    Bokhove, Onno

    2001-01-01

    This report explains the numerical programs behind a comprehensive modeling effort of magma-repository interactions. Magma-repository interactions occur when a magma dike with high-volatile content magma ascends through surrounding rock and encounters a tunnel or drift filled with either a magmatic

  5. Magma emplacement in 3D

    Science.gov (United States)

    Gorczyk, W.; Vogt, K.

    2017-12-01

    Magma intrusion is a major material transfer process in Earth's continental crust. Yet, the mechanical behavior of the intruding magma and its host are a matter of debate. In this study, we present a series of numerical thermo-mechanical experiments on mafic magma emplacement in 3D.In our model, we place the magmatic source region (40 km diameter) at the base of the mantle lithosphere and connect it to the crust by a 3 km wide channel, which may have evolved at early stages of magmatism during rapid ascent of hot magmatic fluids/melts. Our results demonstrate continental crustal response due to magma intrusion. We observe change in intrusion geometries between dikes, cone-sheets, sills, plutons, ponds, funnels, finger-shaped and stock-like intrusions as well as injection time. The rheology and temperature of the host-rock are the main controlling factors in the transition between these different modes of intrusion. Viscous deformation in the warm and deep crust favours host rock displacement and magma pools along the crust-mantle boundary forming deep-seated plutons or magma ponds in the lower to middle-crust. Brittle deformation in the cool and shallow crust induces cone-shaped fractures in the host rock and enables emplacement of finger- or stock-like intrusions at shallow or intermediate depth. A combination of viscous and brittle deformation forms funnel-shaped intrusions in the middle-crust. Low-density source magma results in T-shaped intrusions in cross-section with magma sheets at the surface.

  6. Crystalline heterogeneities and instabilities in thermally convecting magma chamber

    Science.gov (United States)

    Culha, C.; Suckale, J.; Qin, Z.

    2016-12-01

    A volcanic vent can supply different densities of crystals over an eruption time period. This has been seen in Hawai'i's Kilauea Iki 1959 eruption; however it is not common for all Kilauea or basaltic eruptions. We ask the question: Under what conditions can homogenous magma chamber cultivate crystalline heterogeneities? In some laboratory experiments and numerical simulations, a horizontal variation is observed. The region where crystals reside is identified as a retention zone: convection velocity balances settling velocity. Simulations and experiments that observe retention zones assume crystals do not alter the convection in the fluid. However, a comparison of experiments and simulations of convecting magma with crystals suggest that large crystal volume densities and crystal sizes alter fluid flow considerably. We introduce a computational method that fully resolves the crystalline phase. To simulate basaltic magma chambers in thermal convection, we built a numerical solver of the Navier-Stoke's equation, continuity equation, and energy equation. The modeled magma is assumed to be a viscous, incompressible fluid with a liquid and solid phase. Crystals are spherical, rigid bodies. We create Rayleigh-Taylor instability through a cool top layer and hot bottom layer and update magma density while keeping crystal temperature and size constant. Our method provides a detailed picture of magma chambers, which we compare to other models and experiments to identify when and how crystals alter magma chamber convection. Alterations include stratification, differential settling and instabilities. These characteristics are dependent on viscosity, convection vigor, crystal volume density and crystal characteristics. We reveal that a volumetric crystal density variation may occur over an eruption time period, if right conditions are met to form stratifications and instabilities in magma chambers. These conditions are realistic for Kilauea Iki's 1959 eruption.

  7. Energy Extraction in the CERN Large Hadron Collider a Project Overview

    CERN Document Server

    Dahlerup-Petersen, K; Kazmine, B; Medvedko, A S; Sytchev, V V; Vasilev, L B

    2001-01-01

    In case of a resistive transition (quench), fast and reliable extraction of the magnetic energy, stored in the superconducting coils of the electromagnets of a particle collider, represents an important part of its magnet protection system. In general, the quench detectors, the quench heaters and the cold by-pass diodes across each magnet, together with the energy extraction facilities provide the required protection of the quenching superconductors against damage due to local energy dissipation. In CERN's LHC machine the energy stored in each of its eight superconducting dipole chains exceeds 1300 MJ. Following an opening of the extraction switches this energy will be absorbed in large extraction resistors located in the underground collider tunnel or adjacent galleries, during the exponential current decay. Also the sixteen, 13 kA quadrupole chains (QF, QD) and more than one hundred and fifty, 600 A circuits of the corrector magnets will be equipped with extraction systems. The extraction switch-gear is bas...

  8. Indicative energy technology assessment of UK shale gas extraction

    International Nuclear Information System (INIS)

    Hammond, Geoffrey P.; O’Grady, Áine

    2017-01-01

    Highlights: • UK shale gas ‘fracking’ is at a very early stage with an uncertain size of resource. • Shale gas extraction might benefit UK fuel security, as well as jobs and growth. • Potentially harmful environmental ‘side-effects’ must be monitored and regulated. • Gas bills for UK household and industrial consumers are unlikely to fall sharply. • Costs & benefits of shale gas fracking are unevenly distributed between communities. - Abstract: There is at present much interest in unconventional sources of natural gas, especially in shale gas which is obtained by hydraulic fracturing, or ‘fracking’. Boreholes are drilled and then lined with steel tubes so that a mixture of water and sand with small quantities of chemicals – the fracking fluid – can be pumped into them at very high pressure. The sand grains that wedge into the cracks induced in the shale rock by a ‘perforating gun’ then releases gas which returns up the tubes. In the United Kingdom (UK) exploratory drilling is at an early stage, with licences being issued to drill a limited number of test boreholes around the country. However, such activities are already meeting community resistance and controversy. Like all energy technologies it exhibits unwanted ‘side-effects’; these simply differ in their level of severity between the various options. Shale gas may make, for example, a contribution to attaining the UK’s statutory ‘greenhouse gas’ emissions targets, but only if appropriate and robust regulations are enforced. The benefits and disadvantages of shale gas fracking are therefore discussed in order to illustrate a ‘balance sheet’ approach. It is also argued that it is desirable to bring together experts from a range of disciplines in order to carry out energy technology assessments. That should draw on and interact with national and local stakeholders: ‘actors’ both large and small. Community engagement in a genuinely participative process – where the

  9. Essential oil extraction with concentrating solar thermal energy

    OpenAIRE

    Veynandt, François

    2015-01-01

    Material complementari del cas estudi "Essential oil extraction with concentrating solar thermal energy”, part component del llibre "Case studies for developing globally responsible engineers" Peer Reviewed

  10. Weak solutions of magma equations

    International Nuclear Information System (INIS)

    Krishnan, E.V.

    1999-01-01

    Periodic solutions in terms of Jacobian cosine elliptic functions have been obtained for a set of values of two physical parameters for the magma equation which do not reduce to solitary-wave solutions. It was also obtained solitary-wave solutions for another set of these parameters as an infinite period limit of periodic solutions in terms of Weierstrass and Jacobian elliptic functions

  11. Magma flow through elastic-walled dikes

    NARCIS (Netherlands)

    Bokhove, Onno; Woods, A.W.; de Boer, A

    2005-01-01

    A convection–diffusion model for the averaged flow of a viscous, incompressible magma through an elastic medium is considered. The magma flows through a dike from a magma reservoir to the Earth’s surface; only changes in dike width and velocity over large vertical length scales relative to the

  12. Energy distribution extraction of negative charges responsible for positive bias temperature instability

    International Nuclear Information System (INIS)

    Ren Shang-Qing; Yang Hong; Wang Wen-Wu; Tang Bo; Tang Zhao-Yun; Wang Xiao-Lei; Xu Hao; Luo Wei-Chun; Zhao Chao; Yan Jiang; Chen Da-Peng; Ye Tian-Chun

    2015-01-01

    A new method is proposed to extract the energy distribution of negative charges, which results from electron trapping by traps in the gate stack of nMOSFET during positive bias temperature instability (PBTI) stress based on the recovery measurement. In our case, the extracted energy distribution of negative charges shows an obvious dependence on energy, and the energy level of the largest energy density of negative charges is 0.01 eV above the conduction band of silicon. The charge energy distribution below that energy level shows strong dependence on the stress voltage. (paper)

  13. Lunar Magma Ocean Crystallization: Constraints from Fractional Crystallization Experiments

    Science.gov (United States)

    Rapp, J. F.; Draper, D. S.

    2015-01-01

    The currently accepted paradigm of lunar formation is that of accretion from the ejecta of a giant impact, followed by crystallization of a global scale magma ocean. This model accounts for the formation of the anorthosite highlands crust, which is globally distributed and old, and the formation of the younger mare basalts which are derived from a source region that has experienced plagioclase extraction. Several attempts at modelling the crystallization of such a lunar magma ocean (LMO) have been made, but our ever-increasing knowledge of the lunar samples and surface have raised as many questions as these models have answered. Geodynamic models of lunar accretion suggest that shortly following accretion the bulk of the lunar mass was hot, likely at least above the solidus]. Models of LMO crystallization that assume a deep magma ocean are therefore geodynamically favorable, but they have been difficult to reconcile with a thick plagioclase-rich crust. A refractory element enriched bulk composition, a shallow magma ocean, or a combination of the two have been suggested as a way to produce enough plagioclase to account for the assumed thickness of the crust. Recently however, geophysical data from the GRAIL mission have indicated that the lunar anorthositic crust is not as thick as was initially estimated, which allows for both a deeper magma ocean and a bulk composition more similar to the terrestrial upper mantle. We report on experimental simulations of the fractional crystallization of a deep (approximately 100km) LMO with a terrestrial upper mantle-like (LPUM) bulk composition. Our experimental results will help to define the composition of the lunar crust and mantle cumulates, and allow us to consider important questions such as source regions of the mare basalts and Mg-suite, the role of mantle overturn after magma ocean crystallization and the nature of KREEP

  14. Caldera resurgence driven by magma viscosity contrasts.

    Science.gov (United States)

    Galetto, Federico; Acocella, Valerio; Caricchi, Luca

    2017-11-24

    Calderas are impressive volcanic depressions commonly produced by major eruptions. Equally impressive is the uplift of the caldera floor that may follow, dubbed caldera resurgence, resulting from magma accumulation and accompanied by minor eruptions. Why magma accumulates, driving resurgence instead of feeding large eruptions, is one of the least understood processes in volcanology. Here we use thermal and experimental models to define the conditions promoting resurgence. Thermal modelling suggests that a magma reservoir develops a growing transition zone with relatively low viscosity contrast with respect to any newly injected magma. Experiments show that this viscosity contrast provides a rheological barrier, impeding the propagation through dikes of the new injected magma, which stagnates and promotes resurgence. In explaining resurgence and its related features, we provide the theoretical background to account for the transition from magma eruption to accumulation, which is essential not only to develop resurgence, but also large magma reservoirs.

  15. Modeling In-stream Tidal Energy Extraction and Its Potential Environmental Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaoqing; Wang, Taiping; Copping, Andrea; Geerlofs, Simon H.

    2014-09-30

    In recent years, there has been growing interest in harnessing in-stream tidal energy in response to concerns of increasing energy demand and to mitigate climate change impacts. While many studies have been conducted to assess and map tidal energy resources, efforts for quantifying the associated potential environmental impacts have been limited. This paper presents the development of a tidal turbine module within a three-dimensional unstructured-grid coastal ocean model and its application for assessing the potential environmental impacts associated with tidal energy extraction. The model is used to investigate in-stream tidal energy extraction and associated impacts on estuarine hydrodynamic and biological processes in a tidally dominant estuary. A series of numerical experiments with varying numbers and configurations of turbines installed in an idealized estuary were carried out to assess the changes in the hydrodynamics and biological processes due to tidal energy extraction. Model results indicated that a large number of turbines are required to extract the maximum tidal energy and cause significant reduction of the volume flux. Preliminary model results also indicate that extraction of tidal energy increases vertical mixing and decreases flushing rate in a stratified estuary. The tidal turbine model was applied to simulate tidal energy extraction in Puget Sound, a large fjord-like estuary in the Pacific Northwest coast.

  16. Partially molten magma ocean model

    International Nuclear Information System (INIS)

    Shirley, D.N.

    1983-01-01

    The properties of the lunar crust and upper mantle can be explained if the outer 300-400 km of the moon was initially only partially molten rather than fully molten. The top of the partially molten region contained about 20% melt and decreased to 0% at 300-400 km depth. Nuclei of anorthositic crust formed over localized bodies of magma segregated from the partial melt, then grew peripherally until they coverd the moon. Throughout most of its growth period the anorthosite crust floated on a layer of magma a few km thick. The thickness of this layer is regulated by the opposing forces of loss of material by fractional crystallization and addition of magma from the partial melt below. Concentrations of Sr, Eu, and Sm in pristine ferroan anorthosites are found to be consistent with this model, as are trends for the ferroan anorthosites and Mg-rich suites on a diagram of An in plagioclase vs. mg in mafics. Clustering of Eu, Sr, and mg values found among pristine ferroan anorthosites are predicted by this model

  17. Ground source energy in crystalline bedrock - increased energy extraction by using hydraulic fracturing in boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Ramstad, Randi Kalstad

    2004-11-01

    The use of improved equipment and methodology can result in considerable reductions in the drilling costs for medium- to large sized ground source heat pump system in crystalline bedrock. The main point has been to use special techniques within hydraulic fracturing to create a larger heat exchange area in the bedrock, and thus a greater energy extraction per borehole. The energy extraction is based on circulating groundwater. Stimulation with hydraulic fracturing is a well known technique in order to improve borehole yields for drinking water-, oil-, and geothermal purposes. A procedure for injection of propping agents in selected borehole sections, and custom-made equipment for hydraulic fracturing in crystalline bedrock, a double packer, have been developed in this study. The propping agents are likely to ensure a permanent improvement of the hydraulic conductivity in a long-run perspective. In addition to a pre-test, a comprehensive test programme has been performed at each of the two pilot plants at Bryn and at the former property of Energiselskapet Asker og Baerum (EAB) in Baerum municipality outside Oslo, Norway. A total of 125 stimulations with hydraulic fracturing using water-only and hydraulic fracturing with injection of sand have been performed in 9 boreholes. Test pumping and geophysical logging (temperature, electrical conductivity, gamma radiation, optical televiewer and flow measurements) have been carried out in order to document the effect of the hydraulic fracturing. The pilot plants at Bryn and EAB, where the ground source heat pump systems are based on circulating groundwater, have demonstrated the short-period energy extraction, limitations and opportunities of the concept for hydraulic fracturing and increased energy extraction in different geological and hydrogeological areas. The bedrock at Bryn and EAB is characterized as a low-metamorphic sandstone and a nodular limestone, respectively. At Bryn, the five boreholes were organised with a

  18. Energy extraction from a Konoplya–Zhidenko rotating non-Kerr black hole

    Directory of Open Access Journals (Sweden)

    Fen Long

    2018-01-01

    Full Text Available We have investigated the properties of the ergosphere and the energy extraction by Penrose process in a Konoplya–Zhidenko rotating non-Kerr black hole spacetime. We find that the ergosphere becomes thin and the maximum efficiency of energy extraction decreases as the deformation parameter increases. For the case with aM, we find that the maximum efficiency can reach so high that it is almost unlimited as the positive deformation parameter is close to zero, which is a new feature of energy extraction in such kind of rotating non-Kerr black hole spacetime.

  19. Geothermal energy technology: issues, R and D needs, and cooperative arrangements

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    In 1986, the National Research Council, through its Energy Engineering Board, formed the Committee on Geothermal Energy Technology. The committee's study addressed major issues in geothermal energy technology, made recommendations for research and development, and considered cooperative arrangements among government, industry, and universities to facilitate RandD under current severe budget constraints. The report addresses four types of geothermal energy: hydrothermal, geopressured, hot dry rock, and magma systems. Hydrothermal systems are the only type that are now economically competitive commercially. Further technology development by the Department of Energy could make the uneconomical hydrothermal resources commercially attractive to the industry. The economics are more uncertain for the longer-term technologies for extracting energy from geopressured, hot dry rock, and magma systems. For some sites, the cost of energy derived from geopressured and hot dry rock systems is projected within a commercially competitive range. The use of magma energy is too far in the future to make reasonable economic calculations.

  20. Energy-extraction processes from a Kerr black hole immersed in a magnetic field. I. Negative-energy states

    International Nuclear Information System (INIS)

    Dhurandhar, S.V.; Dadhich, N.

    1984-01-01

    This is the first of two papers on the energy-extraction processes near a Kerr black hole immersed in a magnetic field. In this paper we shall consider the consequences of a dipole field extending to infinity matched on to a uniform field in the interior which contains the Kerr black hole. The magnetic fields considered are perturbative in nature. The matching of the fields is imperative owing to the ''no-hair theorem'' and the second law of black-hole physics. Two intriguing situations arising in this context are discussed, namely, (1) the second law of black-hole physics and (2) the law of conservation of energy in an energy-extraction process. At first sight both these laws seem to be violated. These issues arise basically because in the presence of the magnetic field there can exist negative-energy states even for L>0 particles. These issues get resolved by realizing that it is the sign of P/sub c/phi = L-eA/sub cphi/ and not L which determines a corotating or counterrotating orbit. It is also shown that negative-energy states can exist away from the horizon in the presence of either of the fields, the dipole and the uniform, thus favoring energy-extraction processes away from the black hole. This type of energy extraction is solely a consequence of the magnetic field. Also, a fairly detailed analysis of the effective-potential curves is provided, mainly relevant to the existence of negative energies and energy extraction. The formalism of the energy-extraction process will be considered in the second paper

  1. Causal extraction of black hole rotational energy by various kinds of electromagnetic fields

    International Nuclear Information System (INIS)

    Koide, Shinji; Baba, Tamon

    2014-01-01

    Recent general relativistic magnetohydrodynamics (MHD) simulations have suggested that relativistic jets from active galactic nuclei (AGNs) have been powered by the rotational energy of central black holes. Some mechanisms for extraction of black hole rotational energy have been proposed, like the Penrose process, Blandford-Znajek mechanism, MHD Penrose process, and superradiance. The Blandford-Znajek mechanism is the most promising mechanism for the engines of the relativistic jets from AGNs. However, an intuitive interpretation of this mechanism with causality is not yet clarified, while the Penrose process has a clear interpretation for causal energy extraction from a black hole with negative energy. In this paper, we present a formula to build physical intuition so that in the Blandford-Znajek mechanism, as well as in other electromagnetic processes, negative electromagnetic energy plays an important role in causal extraction of the rotational energy of black holes.

  2. Excavation-drier method of energy-peat extraction reduces long-term climatic impact

    Energy Technology Data Exchange (ETDEWEB)

    Silvan, N.; Silvan, K.; Laine, J. [Finnish Forest Research Inst., Parkano (Finland)], e-mail: niko.silvan@metla.fi; Vaisanen, S.; Soukka, R. [Lappeenranta Univ.of Techology (Finland)

    2012-11-01

    Climatic impacts of energy-peat extraction are of increasing concern due to EU emissions trading requirements. A new excavation-drier peat extraction method has been developed to reduce the climatic impact and increase the efficiency of peat extraction. To quantify and compare the soil GHG fluxes of the excavation drier and the traditional milling methods, as well as the areas from which the energy peat is planned to be extracted in the future (extraction reserve area types), soil CO{sub 2}, CH{sub 4} and N{sub 2}O fluxes were measured during 2006-2007 at three sites in Finland. Within each site, fluxes were measured from drained extraction reserve areas, extraction fields and stockpiles of both methods and additionally from the biomass driers of the excavation-drier method. The Life Cycle Assessment (LCA), described at a principal level in ISO Standards 14040:2006 and 14044:2006, was used to assess the long-term (100 years) climatic impact from peatland utilisation with respect to land use and energy production chains where utilisation of coal was replaced with peat. Coal was used as a reference since in many cases peat and coal can replace each other in same power plants. According to this study, the peat extraction method used was of lesser significance than the extraction reserve area type in regards to the climatic impact. However, the excavation-drier method seems to cause a slightly reduced climatic impact as compared with the prevailing milling method. (orig.)

  3. Opportunities for switchable solvents for lipid extraction from wet algal biomass: an energy evaluation

    NARCIS (Netherlands)

    Du, Ying; Schuur, Boelo; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2015-01-01

    Algae are considered an important sustainable feedstock for lipid extraction to produce food ingredients, cosmetics, pharmaceutical products and biofuels. Next to the costs for cultivation, this route is especially hindered by the energy intensity of drying algae prior to extraction and solvent

  4. The magma plumbing system in the Mariana Trough back-arc basin at 18° N

    Science.gov (United States)

    Lai, Zhiqing; Zhao, Guangtao; Han, Zongzhu; Huang, Bo; Li, Min; Tian, Liyan; Liu, Bo; Bu, Xuejiao

    2018-04-01

    Mafic magmas are common in back-arc basin, once stalled in the crust, these magmas may undergo different evolution. In this paper, compositional and textural variations of plagioclase as well as mineral-melt geothermobarometry are presented for basalts erupted from the central Mariana Trough (CMT). These data reveal crystallization conditions and we attempt a reconstruction of the magma plumbing system of the CMT. Plagioclase megacrysts, phenocrysts, microphenocrysts, microlites, olivine, spinel, and clinopyroxene have been recognized in basalt samples, using BSE images and compositional features. The last three minerals are homogeneous as microphenocrysts. Mineral-melt barometry indicates that plagioclase crystals crystallized and eventually grew into phenocrysts and megacrysts in mush zone with depth of 5-9 km, in which the normal zoning plagioclases crystallized in the interval of various batches of basic magma recharging. Plagioclase megacrysts and phenocrysts were dissolved and/or resorbed, when new basic magmas injected into the mush zone near Moho depth. It is inferred that magma extracted from the mush zone, and adiabatically ascended via different pathways. Some basaltic magmas underwent plagioclase and clinopyroxene microphenocrysts crystallization in low-pressure before eruption. Plagioclase microlites and outermost rims probably crystallized after eruption.

  5. UAS Flight Planning Tool for Atmospheric Energy Extraction, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aircraft have been flying point to point missions for the past 100 years. Each flight, the fuel energy is burned based upon an assumed time requirement to transport...

  6. Interaction of coeval felsic and mafic magmas from the Kanker ...

    Indian Academy of Sciences (India)

    66

    20 crystallization of the latter, results in hybrid magmas under the influence of thermal and. 21 chemical exchange. The mechanical exchange occurs between the coexisting magmas due to. 22 viscosity contrast, if the mafic magma enters slightly later into the magma chamber, when the. 23 felsic magma started to crystallize.

  7. Extracting renewable energy from a salinity difference using a capacitor.

    Science.gov (United States)

    Brogioli, Doriano

    2009-07-31

    Completely renewable energy can be produced by using water solutions of different salinity, like river water and sea water. Many different methods are already known, but development is still at prototype stage. Here I report a novel method, based on electric double-layer capacitor technology. Two porous electrodes, immersed in the salt solution, constitute a capacitor. It is first charged, then the salt solution is brought into contact with fresh water. The electrostatic energy increases as the salt concentration of the solution is reduced due to diffusion. This device can be used to turn sources of salinity difference into completely renewable sources of energy. An experimental demonstration is given, and performances and possible improvements are discussed.

  8. A General Mathematical Framework for Calculating Systems-Scale Efficiency of Energy Extraction and Conversion: Energy Return on Investment (EROI) and Other Energy Return Ratios

    OpenAIRE

    Adam R. Brandt; Michael Dale

    2011-01-01

    The efficiencies of energy extraction and conversion systems are typically expressed using energy return ratios (ERRs) such as the net energy ratio (NER) or energy return on investment (EROI). A lack of a general mathematical framework prevents inter-comparison of NER/EROI estimates between authors: methods used are not standardized, nor is there a framework for succinctly reporting results in a consistent fashion. In this paper we derive normalized mathematical forms of four ERRs for energy ...

  9. Energy Efficient Bioethanol Purification by Heat Pump Assisted Extractive Distillation

    NARCIS (Netherlands)

    Kiss, Anton A.; Luo, Hao; Bildea, Costin Sorin

    2015-01-01

    The purification of bioethanol fuel requires an energy demanding separation process to concentrate the diluted streams obtained in the fermentation stage and to overcome the azeotropic behaviour of ethanol-water mixture. The classic separation sequence consists of three distillation columns that

  10. Extraction of potential energy in charge asymmetry coordinate from experimental fission data

    Energy Technology Data Exchange (ETDEWEB)

    Pasca, H. [Joint Institute for Nuclear Research, Dubna (Russian Federation); ' ' Babes-Bolyai' ' Univ., Cluj-Napoca (Romania); Andreev, A.V.; Adamian, G.G. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Antonenko, N.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Tomsk Polytechnic Univ. (Russian Federation). Mathematical Physics Dept.

    2016-12-15

    For fissioning isotopes of Ra, Ac, Th, Pa, and U, the potential energies as a function of the charge asymmetry coordinate are extracted from the experimental charge distributions of the fission fragment and compared with the calculated scission-point driving potentials. The role of the potential energy surfaces in the description of the fission charge distribution is discussed. (orig.)

  11. Impact of Wire Geometry in Energy Extraction from Salinity Differences Using Capacitive Technology

    NARCIS (Netherlands)

    Sales, B.B.; Burheim, O.S.; Liu, F.; Schaetzle, O.; Buisman, C.J.N.; Hamelers, H.V.M.

    2012-01-01

    Energy extraction based on capacitive Donnan potential (CDP) is a recently suggested technique for sustainable power generation. CDP combines the use of ion-exchange membranes and porous carbon electrodes to convert the Gibbs free energy of mixing sea and river water into electric work. The

  12. Minimizing the water and air impacts of unconventional energy extraction

    Science.gov (United States)

    Jackson, R. B.

    2014-12-01

    Unconventional energy generates income and, done well, can reduce air pollution compared to other fossil fuels and even water use compared to fossil fuels and nuclear energy. Alternatively, it could slow the adoption of renewables and, done poorly, release toxic chemicals into water and air. Based on research to date, some primary threats to water resources come from surface spills, wastewater disposal, and drinking-water contamination through poor well integrity. For air resources, an increase in volatile organic compounds and air toxics locally is a potential health threat, but the switch from coal to natural gas for electricity generation will reduce sulfur, nitrogen, mercury, and particulate pollution regionally. Critical needs for future research include data for 1) estimated ultimate recovery (EUR) of unconventional hydrocarbons; 2) the potential for further reductions of water requirements and chemical toxicity; 3) whether unconventional resource development alters the frequency of well-integrity failures; 4) potential contamination of surface and ground waters from drilling and spills; and 5) the consequences of greenhouse gases and air pollution on ecosystems and human health.

  13. Energy Extracting and Quench Protection System in the LHC

    CERN Document Server

    Abu Siam, Mansour

    2016-01-01

    quadrupole magnets. The electromagnets are built of special cables that operate in superconducting state by cooling them to 1.9K (-271.3℃); the superconducting magnets of the LHC are powered in about 1700 electrical circuits. A phenomenon called quench can spontaneously occur in superconducting magnets, which means that the superconductivity is lost in part of their windings. The energy stored within the magnet, up to 1.3 GJ, can cause severe damage. In order to protect the superconducting elements after a resistive transition, the energy is dissipated into a dump resistor installed in series with the magnet chain that is switched into the circuit by opening circuit breakers. The system described above is utilized for magnets installed in the LHC that operate under currents ranging from 600A up to 13kA. For the next LHC upgrade (High Luminosity) there is a need for circuit breakers capable of interrupting high DC currents in a solely inductive circuit within one millisecond and under development of very hig...

  14. Depth of origin of magma in eruptions.

    Science.gov (United States)

    Becerril, Laura; Galindo, Ines; Gudmundsson, Agust; Morales, Jose Maria

    2013-09-26

    Many volcanic hazard factors--such as the likelihood and duration of an eruption, the eruption style, and the probability of its triggering large landslides or caldera collapses--relate to the depth of the magma source. Yet, the magma source depths are commonly poorly known, even in frequently erupting volcanoes such as Hekla in Iceland and Etna in Italy. Here we show how the length-thickness ratios of feeder dykes can be used to estimate the depth to the source magma chamber. Using this method, accurately measured volcanic fissures/feeder-dykes in El Hierro (Canary Islands) indicate a source depth of 11-15 km, which coincides with the main cloud of earthquake foci surrounding the magma chamber associated with the 2011-2012 eruption of El Hierro. The method can be used on widely available GPS and InSAR data to calculate the depths to the source magma chambers of active volcanoes worldwide.

  15. Volcanic emission of radionuclides and magma dynamics

    International Nuclear Information System (INIS)

    Lambert, G.; Le Cloarec, M.F.; Ardouin, B.; Le Roulley, J.C.

    1985-01-01

    210 Pb, 210 Bi and 210 Po, the last decay products of the 238 U series, are highly enriched in volcanic plumes, relative to the magma composition. Moreover this enrichment varies over time and from volcano to volcano. A model is proposed to describe 8 years of measurements of Mt. Etna gaseous emissions. The lead and bismuth coefficients of partition between gaseous and condensated phases in the magma are determined by comparing their concentrations in lava flows and condensated volatiles. In the case of volatile radionuclides, an escaping time is calculated which appears to be related to the volcanic activity. Finally, it is shown that that magma which is degassing can already be partly degassed; it should be considered as a mixture of a few to 50% of deep non-degassed magma with a well degassed superficial magma cell. (orig.)

  16. Shear thinning behaviors in magmas

    Science.gov (United States)

    Vetere, F. P.; Cassetta, M.; Perugini, D.

    2017-12-01

    Studies on magma rheology are of fundamental importance to understanding magmatic processes from depth to surface. Since viscosity is one of the most important parameter controlling eruption mechanisms, as well as lava flow emplacement, a comprehensive knowledge on the evolution of magma viscosities during crystallization is required. We present new viscosity data on partly crystalized basalt, andesite and analogue lavas comparable to those erupted on Mercury's northern volcanic plains. High-temperature viscosity measurements were performed using a rotational Anton Paar RheolabQC viscometer head at the PVRG labs, in Perugia (Italy) (http://pvrg.unipg.it). The relative proportion of phases in each experimental run were determined by image analysis on BS-SEM images at different magnifications; phases are glasses, clinopyroxene, spinel, plagioclase for the basalt, plagioclase and spinel for the andesite and pure enstatite and clinopyroxenes, for the analogue Mercury's composition. Glass and crystalline fractions determined by image analysis well correlate with compositions of residual melts. In order to constrain the viscosity (η) variations as a function of crystallinity, shear rate (γ) was varied from 0.1 to 5 s-1. Viscosity vs. time at constant temperature shows a typical S-shape curve. In particular, for basaltic composition η vary from 3.1-3.8 Pa s [log η] at 1493 K and crystallinity of 19 area % as γ vary from 1.0 to 0.1 s-1; the andesite viscosity evolution is 3.2 and 3.7 Pa s [log η] as γ varies from 1 to 0.1 at 1493 K and crystal content of 17 area %; finally, Mercury's analogue composition was investigated at different temperature ranging from 1533 to 1502 K (Vetere et al., 2017). Results, for γ = 0.1, 1.0 and 5.0 s-1, show viscosity variation between 2.7-4.0, 2.5-3.4 and 2.0-3.0 [log η inPa s] respectively while crystallinity vary from 9 to 27 (area %). As viscosity decreases as shear rate increases, these data points to a shear thinning behaviour

  17. Abnormally large energy spread of electron beams extracted from plasma sources

    Energy Technology Data Exchange (ETDEWEB)

    Winter, H [Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Physik

    1976-07-01

    Intense electron beams extracted from DUOPLASMATRON-plasma cathodes show a high degree of modulation in intensity and an abnormally large energy spread; these facts cannot be explained simply by the temperature of the plasma electrons and the discharge structure. However, an analysis of the discharge stability behaviour and the interaction of source- and extracted beam-plasma leads to an explanation for the observed effects.

  18. An Optimal Control Method for Maximizing the Efficiency of Direct Drive Ocean Wave Energy Extraction System

    Science.gov (United States)

    Chen, Zhongxian; Yu, Haitao; Wen, Cheng

    2014-01-01

    The goal of direct drive ocean wave energy extraction system is to convert ocean wave energy into electricity. The problem explored in this paper is the design and optimal control for the direct drive ocean wave energy extraction system. An optimal control method based on internal model proportion integration differentiation (IM-PID) is proposed in this paper though most of ocean wave energy extraction systems are optimized by the structure, weight, and material. With this control method, the heavy speed of outer heavy buoy of the energy extraction system is in resonance with incident wave, and the system efficiency is largely improved. Validity of the proposed optimal control method is verified in both regular and irregular ocean waves, and it is shown that IM-PID control method is optimal in that it maximizes the energy conversion efficiency. In addition, the anti-interference ability of IM-PID control method has been assessed, and the results show that the IM-PID control method has good robustness, high precision, and strong anti-interference ability. PMID:25152913

  19. An optimal control method for maximizing the efficiency of direct drive ocean wave energy extraction system.

    Science.gov (United States)

    Chen, Zhongxian; Yu, Haitao; Wen, Cheng

    2014-01-01

    The goal of direct drive ocean wave energy extraction system is to convert ocean wave energy into electricity. The problem explored in this paper is the design and optimal control for the direct drive ocean wave energy extraction system. An optimal control method based on internal model proportion integration differentiation (IM-PID) is proposed in this paper though most of ocean wave energy extraction systems are optimized by the structure, weight, and material. With this control method, the heavy speed of outer heavy buoy of the energy extraction system is in resonance with incident wave, and the system efficiency is largely improved. Validity of the proposed optimal control method is verified in both regular and irregular ocean waves, and it is shown that IM-PID control method is optimal in that it maximizes the energy conversion efficiency. In addition, the anti-interference ability of IM-PID control method has been assessed, and the results show that the IM-PID control method has good robustness, high precision, and strong anti-interference ability.

  20. Value of sensitive in-situ environmental assets in energy resource extraction

    International Nuclear Information System (INIS)

    Thampapillai, Dodo J.

    2011-01-01

    The extraction of energy resources and the preservation of sensitive in-situ environmental assets are invariably mutually exclusive alternatives. The opportunity cost value of preserving the environmental assets can be assessed by recourse to resource rent taxes, and threshold values. The case study analysis carried out in this paper suggests that the preservation of these assets could be justifiable on the grounds of “acceptable sacrifice”. - Highlights: ► Resource rents owed to the state from energy resource extraction can be significant. ► Benefits if mining energy resources are over-stated when the role of sensitive environmental assets is ignored. ► Threshold values could help to resolve conflicts between environmental preservation and resource extraction.

  1. Numerical modeling of bubble dynamics in magmas

    Science.gov (United States)

    Huber, Christian; Su, Yanqing; Parmigiani, Andrea

    2014-05-01

    Understanding the complex non-linear physics that governs volcanic eruptions is contingent on our ability to characterize the dynamics of bubbles and its effect on the ascending magma. The exsolution and migration of bubbles has also a great impact on the heat and mass transport in and out of magma bodies stored at shallow depths in the crust. Multiphase systems like magmas are by definition heterogeneous at small scales. Although mixture theory or homogenization methods are convenient to represent multiphase systems as a homogeneous equivalent media, these approaches do not inform us on possible feedbacks at the pore-scale and can be significantly misleading. In this presentation, we discuss the development and application of bubble-scale multiphase flow modeling to address the following questions : How do bubbles impact heat and mass transport in magma chambers ? How efficient are chemical exchanges between the melt and bubbles during magma decompression? What is the role of hydrodynamic interactions on the deformation of bubbles while the magma is sheared? Addressing these questions requires powerful numerical methods that accurately model the balance between viscous, capillary and pressure stresses. We discuss how these bubble-scale models can provide important constraints on the dynamics of magmas stored at shallow depth or ascending to the surface during an eruption.

  2. Evidence for seismogenic fracture of silicic magma.

    Science.gov (United States)

    Tuffen, Hugh; Smith, Rosanna; Sammonds, Peter R

    2008-05-22

    It has long been assumed that seismogenic faulting is confined to cool, brittle rocks, with a temperature upper limit of approximately 600 degrees C (ref. 1). This thinking underpins our understanding of volcanic earthquakes, which are assumed to occur in cold rocks surrounding moving magma. However, the recent discovery of abundant brittle-ductile fault textures in silicic lavas has led to the counter-intuitive hypothesis that seismic events may be triggered by fracture and faulting within the erupting magma itself. This hypothesis is supported by recent observations of growing lava domes, where microearthquake swarms have coincided with the emplacement of gouge-covered lava spines, leading to models of seismogenic stick-slip along shallow shear zones in the magma. But can fracturing or faulting in high-temperature, eruptible magma really generate measurable seismic events? Here we deform high-temperature silica-rich magmas under simulated volcanic conditions in order to test the hypothesis that high-temperature magma fracture is seismogenic. The acoustic emissions recorded during experiments show that seismogenic rupture may occur in both crystal-rich and crystal-free silicic magmas at eruptive temperatures, extending the range of known conditions for seismogenic faulting.

  3. Examining shear processes during magma ascent

    Science.gov (United States)

    Kendrick, J. E.; Wallace, P. A.; Coats, R.; Lamur, A.; Lavallée, Y.

    2017-12-01

    Lava dome eruptions are prone to rapid shifts from effusive to explosive behaviour which reflects the rheology of magma. Magma rheology is governed by composition, porosity and crystal content, which during ascent evolves to yield a rock-like, viscous suspension in the upper conduit. Geophysical monitoring, laboratory experiments and detailed field studies offer the opportunity to explore the complexities associated with the ascent and eruption of such magmas, which rest at a pivotal position with regard to the glass transition, allowing them to either flow or fracture. Crystal interaction during flow results in strain-partitioning and shear-thinning behaviour of the suspension. In a conduit, such characteristics favour the formation of localised shear zones as strain is concentrated along conduit margins, where magma can rupture and heal in repetitive cycles. Sheared magmas often record a history of deformation in the form of: grain size reduction; anisotropic permeable fluid pathways; mineral reactions; injection features; recrystallisation; and magnetic anomalies, providing a signature of the repetitive earthquakes often observed during lava dome eruptions. The repetitive fracture of magma at ( fixed) depth in the conduit and the fault-like products exhumed at spine surfaces indicate that the last hundreds of meters of ascent may be controlled by frictional slip. Experiments on a low-to-high velocity rotary shear apparatus indicate that shear stress on a slip plane is highly velocity dependent, and here we examine how this influences magma ascent and its characteristic geophysical signals.

  4. CMOS circuits for piezoelectric energy harvesters efficient power extraction, interface modeling and loss analysis

    CERN Document Server

    Hehn, Thorsten

    2014-01-01

    This book deals with the challenge of exploiting ambient vibrational energy which can be used to power small and low-power electronic devices, e.g. wireless sensor nodes. Generally, particularly for low voltage amplitudes, low-loss rectification is required to achieve high conversion efficiency. In the special case of piezoelectric energy harvesting, pulsed charge extraction has the potential to extract more power compared to a single rectifier. For this purpose, a fully autonomous CMOS integrated interface circuit for piezoelectric generators which fulfills these requirements is presented.Due

  5. The energy efficiency of oil sands extraction: Energy return ratios from 1970 to 2010

    International Nuclear Information System (INIS)

    Brandt, Adam R.; Englander, Jacob; Bharadwaj, Sharad

    2013-01-01

    It has been argued that the oil sands industry is not energy efficient: comparatively large energy inputs are required per unit of energy output from oil sands operations. Unfortunately, quantitative work to date in this area has suffered from poor data availability and uncertain methods. We apply a new methodology and new dataset to compute ERRs (energy return ratios) for the oil sands industry. We collected monthly oil sands energy consumption and output data from 1970 to 2010. Current oil sands operations have mine mouth NERs (net energy returns) of about 6 GJ output per GJ of energy consumed and point of use energy returns of about 3 GJ/GJ. Long-term trends show oil sands operations becoming significantly more efficient: point of use NER increased from about 1 GJ/GJ in 1970 to 3 GJ/GJ in 2010. These energy returns are lower than those observed in historical conventional oil operations, but low energy returns are not likely to hinder development of oil sands operations due to the large resource in place and the ability for largely self-fueled pathways to return significant amounts of energy to society for every unit of external energy supplied. - Highlights: • Oil sands operations have become significantly more energy efficient over the history of the industry. • Oil sands production is largely fueled with energy from the bitumen resource itself, making external energy returns high. • Oil sands production is still significantly less efficient than conventional oil production

  6. A General Mathematical Framework for Calculating Systems-Scale Efficiency of Energy Extraction and Conversion: Energy Return on Investment (EROI and Other Energy Return Ratios

    Directory of Open Access Journals (Sweden)

    Adam R. Brandt

    2011-08-01

    Full Text Available The efficiencies of energy extraction and conversion systems are typically expressed using energy return ratios (ERRs such as the net energy ratio (NER or energy return on investment (EROI. A lack of a general mathematical framework prevents inter-comparison of NER/EROI estimates between authors: methods used are not standardized, nor is there a framework for succinctly reporting results in a consistent fashion. In this paper we derive normalized mathematical forms of four ERRs for energy extraction and conversion pathways. A bottom-up (process model formulation is developed for an n-stage energy harvesting and conversion pathway with various system boundaries. Formations with the broadest system boundaries use insights from life cycle analysis to suggest a hybrid process model/economic input output based framework. These models include indirect energy consumption due to external energy inputs and embodied energy in materials. Illustrative example results are given for simple energy extraction and conversion pathways. Lastly, we discuss the limitations of this approach and the intersection of this methodology with “top-down” economic approaches.

  7. EXTRACT

    DEFF Research Database (Denmark)

    Pafilis, Evangelos; Buttigieg, Pier Luigi; Ferrell, Barbra

    2016-01-01

    The microbial and molecular ecology research communities have made substantial progress on developing standards for annotating samples with environment metadata. However, sample manual annotation is a highly labor intensive process and requires familiarity with the terminologies used. We have the...... and text-mining-assisted curation revealed that EXTRACT speeds up annotation by 15-25% and helps curators to detect terms that would otherwise have been missed.Database URL: https://extract.hcmr.gr/......., organism, tissue and disease terms. The evaluators in the BioCreative V Interactive Annotation Task found the system to be intuitive, useful, well documented and sufficiently accurate to be helpful in spotting relevant text passages and extracting organism and environment terms. Comparison of fully manual...

  8. Power Take-Off with Integrated Resonator for Energy Extraction from Linear Motions

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a magnetic gear for converting linear motion into rotational motion and vice versa. The present invention converts slow linear irregular oscillating motion of wave energy devices into torque on a high speed shaft for powering a generator while making the wave energy device...... of sea or ocean waves into useful energy, such as electricity. The invention relates to the control and operation of a magnetic gear based motor/generator system. The invention provides a high force density electric powered linear actuator....... resonate with the waves. The invention relates to the field of energy-harvesting from energy sources, where the energy-harvesting requires the extraction of energy from slow and often irregular reciprocating motion of bodies. The present invention relates to a wave power apparatus for converting power...

  9. Extraction design and low energy beam transport optimization of space charge dominated multispecies ion beam sources

    International Nuclear Information System (INIS)

    Delferriere, O.; De Menezes, D.

    2004-01-01

    In all accelerator projects, the low energy part of the accelerator has to be carefully optimized to match the beam characteristic requirements of the higher energy parts. Since 1994 with the beginning of the Injector of Protons for High Intensity (IPHI) project and Source of Light Ions with High Intensities (SILHI) electron cyclotron resonance (ECR) ion source development at CEA/Saclay, we are using a set of two-dimensional (2D) codes for extraction system optimization (AXCEL, OPERA-2D) and beam transport (MULTIPART). The 95 keV SILHI extraction system optimization has largely increased the extracted current, and improved the beam line transmission. From these good results, a 130 mA D + extraction system for the International Fusion Material Irradiation Facility project has been designed in the same way as SILHI one. We are also now involved in the SPIRAL 2 project for the building of a 40 keV D + ECR ion source, continuously tunable from 0.1 to 5 mA, for which a special four-electrode extraction system has been studied. In this article we will describe the 2D design process and present the different extraction geometries and beam characteristics. Simulation results of SILHI H + beam emittance will be compared with experimental measurements

  10. Origin of silicic magmas along the Central American volcanic front: Genetic relationship to mafic melts

    Science.gov (United States)

    Vogel, Thomas A.; Patino, Lina C.; Eaton, Jonathon K.; Valley, John W.; Rose, William I.; Alvarado, Guillermo E.; Viray, Ela L.

    2006-09-01

    Silicic pyroclastic flows and related deposits are abundant along the Central American volcanic front. These silicic magmas erupted through both the non-continental Chorotega block to the southeast and the Paleozoic continental Chortis block to the northwest. The along-arc variations of the silicic deposits with respect to diagnostic trace element ratios (Ba/La, U/Th, Ce/Pb), oxygen isotopes, Nd and Sr isotope ratios mimic the along-arc variation in the basaltic and andesitic lavas. This variation in the lavas has been interpreted to indicate relative contributions from the slab and asthenosphere to the basaltic magmas [Carr, M.J., Feigenson, M.D., Bennett, E.A., 1990. Incompatible element and isotopic evidence for tectonic control of source mixing and melt extraction along the Central American arc. Contributions to Mineralogy and Petrology, 105, 369-380.; Patino, L.C., Carr, M.J. and Feigenson, M.D., 2000. Local and regional variations in Central American arc lavas controlled by variations in subducted sediment input. Contributions to Mineralogy and Petrology, 138 (3), 265-283.]. With respect to along-arc trends in basaltic lavas the largest contribution of slab fluids is in Nicaragua and the smallest input from the slab is in central Costa Rica — similar trends are observed in the silicic pyroclastic deposits. Data from melting experiments of primitive basalts and basaltic andesites demonstrate that it is difficult to produce high K 2O/Na 2O silicic magmas by fractional crystallization or partial melting of low-K 2O/Na 2O sources. However fractional crystallization or partial melting of medium- to high-K basalts can produce these silicic magmas. We interpret that the high-silica magmas associated Central America volcanic front are partial melts of penecontemporaneous, mantle-derived, evolved magmas that have ponded and crystallized in the mid-crust — or are melts extracted from these nearly completely crystallized magmas.

  11. An Energy Conservation Approach to Adsorbate-Induced Surface Stress and the Extraction of Binding Energy Using Nanomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Pinnaduwage, Lal A [ORNL; Boiadjiev, Vassil I [ORNL; Fernando, G. W. [University of Connecticut, Storrs; Hawk, J. E. [Oak Ridge National Laboratory (ORNL); Wijewardhana, L.C. R. [University of Cincinnati; Gehl, Anthony C [ORNL

    2008-01-01

    Microcantilevers are ideally-suited for the study of surface phenomena due to their large surface-to-volume ratios, which amplify surface effects. We show that when guest molecules bind to atoms/molecules on a microcantilever surface, the released binding energy is retained in the host surface, leading to a metastable state where the excess energy on the surface is manifested as an increase in surface stress leading to the bending of the microcantilever. When the excess energy is released, the microcantilever relaxes back to the original state, and the relaxation time depends on the particular binding process involved. Such experiments were conducted for three binding processes in vapor phase experiments: physisorption, hydrogen bonding, and chemisorption. To our knowledge, such an energy conservation approach has not been taken into account in adsorbate-induced surface effect investigations. Furthermore, these experiments illustrate that detailed molecular-level information on binding energies can be extracted from this simple micromechanical sensor.

  12. Comments on 'Generation of Deccan Trap magmas'

    Indian Academy of Sciences (India)

    R.Narasimhan(krishtel emaging)1461 1996 Oct 15 13:05:22

    Comments on 'Generation of Deccan Trap magmas' by Gautam Sen ... Department of Geology & Geophysics, School of Ocean & Earth Science & Technology (SOEST), University of .... Mahoney J J, Sheth H C, Chandrasekharan D and Peng Z.

  13. The Boycott effect in magma chambers

    Science.gov (United States)

    Blanchette, F.; Peacock, T.; Bush, J. W. M.

    2004-03-01

    We investigate the plausibility of the stratified Boycott effect as a source of layering in magma chambers. Crystal settling within the magma chamber will generate buoyant fluid near the sloping sidewalls whose vertical ascent may be limited by the ambient stratification associated with vertical gradients in SiO2. The resulting flow may be marked by a layered structure, each layer taking the form of a convection cell spanning the lateral extent of the magma chamber. Using parameters relevant to magma chambers, we estimate that such convection cells would be established over a timescale of a month and have a depth on the order of 4m, which is roughly consistent with field observations of strata within solidified chambers.

  14. Mainstreaming Governance in Tajikistan through its Energy, Extractives, and Public Procurement Sectors

    OpenAIRE

    Mikulova, Kristina; Johns, Kimberly; Kunicova, Jana

    2014-01-01

    The governance partnership facility (GPF) supported program mainstreaming governance in Tajikistan portfolio (FY2010-14) was a landmark achievement in applying governance analysis and looking for entry points to improve transparency and accountability in key sectors in Tajikistan. This brief provides recommendations from its energy-efficiency audit, the extractive industries sector, and pu...

  15. Silicic magma generation at Askja volcano, Iceland

    Science.gov (United States)

    Sigmarsson, O.

    2009-04-01

    Rate of magma differentiation is an important parameter for hazard assessment at active volcanoes. However, estimates of these rates depend on proper understanding of the underlying magmatic processes and magma generation. Differences in isotope ratios of O, Th and B between silicic and in contemporaneous basaltic magmas have been used to emphasize their origin by partial melting of hydrothermally altered metabasaltic crust in the rift-zones favoured by a strong geothermal gradient. An alternative model for the origin of silicic magmas in the Iceland has been proposed based on U-series results. Young mantle-derived mafic protolith is thought to be metasomatized and partially melted to form the silicic end-member. However, this model underestimates the compositional variations of the hydrothermally-altered basaltic crust. New data on U-Th disequilibria and O-isotopes in basalts and dacites from Askja volcano reveal a strong correlation between (230Th/232Th) and delta 18O. The 1875 AD dacite has the lowest Th- and O isotope ratios (0.94 and -0.24 per mille, respectively) whereas tephra of evolved basaltic composition, erupted 2 months earlier, has significantly higher values (1.03 and 2.8 per mille, respectively). Highest values are observed in the most recent basalts (erupted in 1920 and 1961) inside the Askja caldera complex and out on the associated fissure swarm (Sveinagja basalt). This correlation also holds for older magma such as an early Holocene dacites, which eruption may have been provoked by rapid glacier thinning. Silicic magmas at Askja volcano thus bear geochemical signatures that are best explained by partial melting of extensively hydrothermally altered crust and that the silicic magma source has remained constant during the Holocene at least. Once these silicic magmas are formed they appear to erupt rapidly rather than mixing and mingling with the incoming basalt heat-source that explains lack of icelandites and the bi-modal volcanism at Askja

  16. Energy Extraction from a Hypothetical MHK Array in a Section of the Mississippi River

    Science.gov (United States)

    Barco, J.; James, S. C.; Roberts, J. D.; Jones, C. A.; Jepsen, R. A.

    2010-12-01

    The world is facing many challenges meeting the energy demands for the future. Growing populations and developing economies as well as increasing energy expenditures highlight the need for a spectrum of energy sources. Concerns about pollution and climate change have led to increased interest in all forms of renewable energy to stabilize or decrease consumption of fossil fuels. One promising renewable is marine and hydrokinetic (MHK) energy, which has the potential to make important contributions to energy portfolios of the future. However, a primary question remains: How much energy can be extracted from MHK devices in rivers and oceans without significant environmental effects? This study focuses on the potential energy extraction from different hypothetical MHK array configurations in a section of the Mississippi River located near to Scotlandville Bend, Louisiana. Bathymetry data, obtained from Free Flow Power Corporation (FFP) via the US Army Corps bathymetry survey library, were interpolated onto a DELFT3D curvilinear, orthogonal grid of the system using ArcGIS 9.3.1. Boundary conditions are constrained by the upstream and downstream river flow rates and gage heights obtained from USGS website. Acoustic Doppler Current Profiler (ADCP) measurements obtained from FFP are used for pre-array model validation. Energy extraction is simulated using momentum sinks recently coded into SNL-EFDC, which is an augmented version of US EPA’s Environmental Fluid Dynamics Code (EFDC). SNL-EFDC model includes a new module which considers energy removal by MHK devices and commensurate changes to the turbulent kinetic energy and turbulent kinetic energy dissipation rate. As expected, average velocities decrease downstream of each MHK device due to energy extraction and blunt-body form drag from the MHK support structures. Changes in the flow field can alter sediment transport dynamics around and downstream of an MHK array; various hypothetical scenarios are examined. This

  17. Territorial approach to increased energy consumption of water extraction from depletion of a highlands Mexican aquifer.

    Science.gov (United States)

    Fonseca, Carlos Roberto; Esteller, María Vicenta; Díaz-Delgado, Carlos

    2013-10-15

    This work proposes a method to estimate increased energy consumption of pumping caused by a drawdown of groundwater level and the equivalent energy consumption of the motor-pump system in an aquifer under intensive exploitation. This method has been applied to the Valley of Toluca aquifer, located in the Mexican highlands, whose intensive exploitation is reflected in a decline in the groundwater level of between 0.10 and 1.6 m/year. Results provide a summary of energy consumption and a map of energy consumption isopleths showing the areas that are most susceptible to increases in energy consumption due to pumping. The proposed method can be used to estimate the effect of the intensive exploitation of the Valley of Toluca aquifer on the energy consumption of groundwater extraction. Finding reveals that, for the year 2006, groundwater extraction in the urban zone required 2.39 times more energy than the conditions observed 38 years earlier. In monetary terms, this reflects an increase of USD$ 3 million annually, according to 2005 energy production costs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Magma Dynamics at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    D. Krier

    2005-01-01

    Small-volume basaltic volcanic activity at Yucca Mountain has been identified as one of the potential events that could lead to release of radioactive material from the U.S. Department of Energy (DOE) designated nuclear waste repository at Yucca Mountain. Release of material could occur indirectly as a result of magmatic dike intrusion into the repository (with no associated surface eruption) by changing groundwater flow paths, or as a result of an eruption (dike intrusion of the repository drifts, followed by surface eruption of contaminated ash) or volcanic ejection of material onto the Earth's surface and the redistribution of contaminated volcanic tephra. Either release method includes interaction between emplacement drifts and a magmatic dike or conduit, and natural (geologic) processes that might interrupt or halt igneous activity. This analysis provides summary information on two approaches to evaluate effects of disruption at the repository by basaltic igneous activity: (1) descriptions of the physical geometry of ascending basaltic dikes and their interaction with silicic host rocks similar in composition to the repository host rocks; and (2) a summary of calculations developed to quantify the response of emplacement drifts that have been flooded with magma and repressurized following blockage of an eruptive conduit. The purpose of these analyses is to explore the potential consequences that could occur during the full duration of an igneous event

  19. Magma Dynamics at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. Krier

    2005-08-29

    Small-volume basaltic volcanic activity at Yucca Mountain has been identified as one of the potential events that could lead to release of radioactive material from the U.S. Department of Energy (DOE) designated nuclear waste repository at Yucca Mountain. Release of material could occur indirectly as a result of magmatic dike intrusion into the repository (with no associated surface eruption) by changing groundwater flow paths, or as a result of an eruption (dike intrusion of the repository drifts, followed by surface eruption of contaminated ash) or volcanic ejection of material onto the Earth's surface and the redistribution of contaminated volcanic tephra. Either release method includes interaction between emplacement drifts and a magmatic dike or conduit, and natural (geologic) processes that might interrupt or halt igneous activity. This analysis provides summary information on two approaches to evaluate effects of disruption at the repository by basaltic igneous activity: (1) descriptions of the physical geometry of ascending basaltic dikes and their interaction with silicic host rocks similar in composition to the repository host rocks; and (2) a summary of calculations developed to quantify the response of emplacement drifts that have been flooded with magma and repressurized following blockage of an eruptive conduit. The purpose of these analyses is to explore the potential consequences that could occur during the full duration of an igneous event.

  20. Results from Commissioning of the Energy Extraction Facilities of the LHC Machine

    CERN Document Server

    Coelingh, G J; Mess, K H

    2008-01-01

    The risk of damage to the superconducting magnets, bus bars and current leads of the LHC machine in case of a resistive transition (quench) is being minimized by adequate protection. The protection is based on early quench detection, bypassing the quenching magnets by cold diodes, energy density dilution in the quenching magnets using heaters and, eventually, energy extraction. For two hundred and twenty-six LHC circuits (600 A and 13 kA) extraction of the stored magnetic energy to external dump resistors was required. All these systems are now installed in the machine and the final hardware commissioning has been undertaken. After a short description of the topology and definitive features, layouts and parameters of these systems the paper will focus on the results from their successful commissioning and an analysis of the system performance.

  1. The Krafla International Testbed (KMT): Ground Truth for the New Magma Geophysics

    Science.gov (United States)

    Brown, L. D.; Kim, D.; Malin, P. E.; Eichelberger, J. C.

    2017-12-01

    Recent developments in geophysics such as large N seismic arrays , 4D (time lapse) subsurface imaging and joint inversion algorithms represent fresh approaches to delineating and monitoring magma in the subsurface. Drilling at Krafla, both past and proposed, are unique opportunities to quantitatively corroborate and calibrate these new technologies. For example, dense seismic arrays are capable of passive imaging of magma systems with resolutions comparable to that achieved by more expensive (and often logistically impractical) controlled source surveys such as those used in oil exploration. Fine details of the geometry of magma lenses, feeders and associated fluid bearing fracture systems on the scale of meters to tens of meters are now realistic targets for surface seismic surveys using ambient energy sources, as are detection of their temporal variations. Joint inversions, for example of seismic and MT measurements, offer the promise of tighter quantitative constraints on the physical properties of the various components of magma and related geothermal systems imaged by geophysics. However, the accuracy of such techniques will remain captive to academic debate without testing against real world targets that have been directly sampled. Thus application of these new techniques to both guide future drilling at Krafla and to be calibrated against the resulting borehole observations of magma are an important step forward in validating geophysics for magma studies in general.

  2. Effect of power shape on energy extraction from microbial fuel cell

    Science.gov (United States)

    Alaraj, Muhannad; Feng, Shuo; Roane, Timberley M.; Park, Jae-Do

    2017-10-01

    Microbial fuel cells (MFCs) generate renewable energy in the form of direct current (DC) power. Harvesting energy from MFCs started with passive components such as resistors and capacitors, then charge pumps were introduced with some more advantages. Power electronics converters were later preferred due to their higher efficiency and controllability; however, they introduce high frequency current ripple due to their high frequency switching. In this paper, the effect of shape of power extraction on MFC performance was investigated using three types of current shapes: continuous, square-wave, and triangular-wave. Simultaneously, chemical parameters, such as pH, dissolved oxygen, electrical conductivity, and redox potential, in the anode chamber were monitored to see how these parameters change with the shape of the electrical power extraction. Results showed that the shape of the extracted current did not have a substantial effect on the MFC life span, output power, and energy extraction, nor on the chemical parameters. The outcome of this study provided insight for the electrical impact by power electronics converters on some microbial and chemical aspects of an MFC system.

  3. The comparison of extraction of energy in two-cascade and one-cascade targets

    Energy Technology Data Exchange (ETDEWEB)

    Dolgoleva, G. V., E-mail: dolgg@list.ru [National Research Tomsk State University, 36, Lenin Ave., 634050, Tomsk (Russian Federation); Ponomarev, I. V., E-mail: wingof17@mail.ru [Moscow State University, Department of Mechanics and Mathematics, 1, Vorobyovy Gory, Moscow,119961 (Russian Federation)

    2016-01-15

    The paper is devoted to numerical designing of cylindrical microtargets on the basis of shock-free compression. When designing microtargets for the controlled thermonuclear fusion, the core tasks are to select geometry and make-up of layers, and the law of energy embedding as well, which allow receiving of “burning” of deuterium- tritium mix, that is, the existence of thermonuclear reactions of working area. Yet, the energy yield as a result of thermonuclear reactions has to be more than the embedded energy (the coefficient of amplification is more than a unit). So, an important issue is the value of the embedded energy. The purpose of the present paper is to study the extraction of energy by working DT area in one-cascade and two-cascade targets. A bigger extraction of energy will contribute to a better burning of DT mix and a bigger energy yield as a result of thermonuclear reactions. The comparison of analytical results to numerical calculations is carried out. The received results show advantages of a two-cascade target compared to a one-cascade one.

  4. Synchronous timing of multi-energy fast beam extraction during a single AGS cycle

    International Nuclear Information System (INIS)

    Gabusi, J.; Naase, S.

    1985-01-01

    Synchronous triggering of fast beams is required because the field of Kicker Magnets must rise within the open space between one beam bunch and the next. Within the Brookhaven AGS, Fast Extracted Beam (FEB) triggering combines nominal timing, based on beam energy with bunch-to-bunch synchronization, based on the accelerating rf waveform. During beam acceleration, a single bunch is extracted at 22 GeV/c and within the same AGS cycle, the remaining eleven bunches are extracted at 28.4 GeV/c. When the single bunch is extracted, a ''hole'', which is left in the remaining circulating beam, can appear in random locations within the second extraction during successive AGS cycles. To overcome this problem, a synchronous rf/12 counting scheme and logic circuitry are used to keep track of the bunch positions relative to each other, and to place the ''hole'' in any desired location within the second extraction. The rf/12 signal is used also to synchronize experimenters triggers

  5. A critical discussion of the extraction of the {rho} - parameter at high energy hadron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Nicolescu, B. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire

    1996-12-31

    A new and general method is proposed for the extraction of the semi theoretical {rho}-parameter from the raw dN/dt data. By using this method it is shown that the exponential form of the hadron amplitude in the diffraction peak at high energy is doubtful and that the value {rho} = 0.135 {+-} 0.015, extracted from the very precise UA4/2 dN/dt data at {radical}s 541 GeV, is probably wrong. (author) 4 refs.

  6. Low-energy ion beam extraction and transport: Experiment--computer comparison

    International Nuclear Information System (INIS)

    Spaedtke, P.; Brown, I.; Fojas, P.

    1994-01-01

    Ion beam formation at low energy (∼1 keV or so) is more difficult to accomplish than at high energy because of beam blowup by space-charge forces in the uncompensated region within the extractor, an effect which is yet more pronounced for heavy ions and for high beam current density. For the same reasons, the extracted ion beam is more strongly subject to space charge blowup than higher energy beams if it is not space-charge neutralized to a high degree. A version of vacuum arc ion source with an extractor that produces low-energy metal ion beams at relatively high current (∼0.5--10 kV at up to ∼100 mA) using a multi-aperture, accel--decel extractor configuration has been created. The experimentally observed beam extraction characteristics of this source is compared with those predicted using the AXCEL-INP code, and the implied downstream beam transport with theoretical expectations. It is concluded that the low-energy extractor performance is in reasonable agreement with the code, and that good downstream space charge neutralization is obtained. Here, the code and the experimental results are described, and the features that contribute to good low-energy performance are discussed

  7. Radiographic visualization of magma dynamics in an erupting volcano.

    Science.gov (United States)

    Tanaka, Hiroyuki K M; Kusagaya, Taro; Shinohara, Hiroshi

    2014-03-10

    Radiographic imaging of magma dynamics in a volcanic conduit provides detailed information about ascent and descent of magma, the magma flow rate, the conduit diameter and inflation and deflation of magma due to volatile expansion and release. Here we report the first radiographic observation of the ascent and descent of magma along a conduit utilizing atmospheric (cosmic ray) muons (muography) with dynamic radiographic imaging. Time sequential radiographic images show that the top of the magma column ascends right beneath the crater floor through which the eruption column was observed. In addition to the visualization of this magma inflation, we report a sequence of images that show magma descending. We further propose that the monitoring of temporal variations in the gas volume fraction of magma as well as its position in a conduit can be used to support existing eruption prediction procedures.

  8. Extraction of low-energy negative oxygen ions for thin film formation

    International Nuclear Information System (INIS)

    Vasquez, M. Jr.; Sasaki, D.; Kasuya, T.; Wada, M.; Maeno, S.

    2011-01-01

    Coextraction of low-energy positive and negative ions were performed using a plasma sputter-type ion source system driven by a 13.56 MHz radio frequency (rf) power. Titanium (Ti) atoms were sputtered out from a target and the sputtered neutrals were postionized in oxygen/argon (O 2 /Ar) plasma prior to extraction. The negative O ions were surface-produced and self-extracted. Mass spectral analyses of the extracted ion beams revealed the dependence of the ion current on the incident rf power, induced target bias and O 2 /Ar partial pressure ratio. Ti + current was found to be dependent on Ar + current and reached a saturation value with increasing O 2 partial pressure while the O - current showed a peak current at around 1:9 O 2 /Ar partial pressure ratio. Ti + current was several orders of magnitude higher than that of the O - current.

  9. Rapid Crystallization of the Bishop Magma

    Science.gov (United States)

    Gualda, G. A.; Anderson, A. T.; Sutton, S. R.

    2007-12-01

    Substantial effort has been made to understand the longevity of rhyolitic magmas, and particular attention has been paid to the systems in the Long Valley area (California). Recent geochronological data suggest discrete magma bodies that existed for hundreds of thousands of years. Zircon crystallization ages for the Bishop Tuff span 100-200 ka, and were interpreted to reflect slow crystallization of a liquid-rich magma. Here we use the diffusional relaxation of Ti zoning in quartz to investigate the longevity of the Bishop magma. We have used such an approach to show the short timescales of crystallization of Ti-rich rims on quartz from early- erupted Bishop Tuff. We have now recognized Ti-rich cores in quartz that can be used to derive the timescales of their crystallization. We studied four samples of the early-erupted Bishop. Hand-picked crystals were mounted on glass slides and polished. Cathodoluminescence (CL) images were obtained using the electron microprobe at the University of Chicago. Ti zoning was documented using the GeoSoilEnviroCARS x-ray microprobe at the Advanced Photon Source (Argonne National Lab). Quartz crystals in all 4 samples include up to 3 Ti-bearing zones: a central core (50-100 μm in diameter, ca. 50 ppm Ti), a volumetrically predominant interior (~40 ppm Ti), and in some crystals a 50-100 μm thick rim (50 ppm Ti). Maximum estimates of core residence times were calculated using a 1D diffusion model, as the time needed to smooth an infinitely steep profile to fit the observed profile. Surprisingly, even for the largest crystals studied - ca. 2 mm in diameter - core residence times are less than 1 ka. Calculated growth rates imply that even cm-sized crystals crystallized in less than 10 ka. Crystal size distribution data show that crystals larger than 3 mm are exceedingly rare, such that the important inference is that the bulk of the crystallization of the early-erupted Bishop magma occurred in only a few thousand years. This timescale

  10. Photo-generated carriers lose energy during extraction from polymer-fullerene solar cells

    KAUST Repository

    Melianas, Armantas

    2015-11-05

    In photovoltaic devices, the photo-generated charge carriers are typically assumed to be in thermal equilibrium with the lattice. In conventional materials, this assumption is experimentally justified as carrier thermalization completes before any significant carrier transport has occurred. Here, we demonstrate by unifying time-resolved optical and electrical experiments and Monte Carlo simulations over an exceptionally wide dynamic range that in the case of organic photovoltaic devices, this assumption is invalid. As the photo-generated carriers are transported to the electrodes, a substantial amount of their energy is lost by continuous thermalization in the disorder broadened density of states. Since thermalization occurs downward in energy, carrier motion is boosted by this process, leading to a time-dependent carrier mobility as confirmed by direct experiments. We identify the time and distance scales relevant for carrier extraction and show that the photo-generated carriers are extracted from the operating device before reaching thermal equilibrium.

  11. Computer modelling of a linear turbine for extracting energy from slow-flowing waters

    International Nuclear Information System (INIS)

    Raykov, Plamen

    2014-01-01

    The aim of the paper is to describe the main relationships in the process of designing linear chain turbines with blades and their accompanying devices for obtaining energy from slow flowing waters. Based on the shortcomings of previous types of linear turbines a new concept for arrangement of the blades angles with respect to the flowing water was developed. The dependencies of the geometrical parameters of designed new type linear water turbine and the force applied by the flowing water to the blades are obtained. The optimal relationship between velocity of stream water and extracted power is calculated. The ratio between power characteristics of the extracted energy for different speeds of blades and inclination angle are presented. On the basis of the theoretical results a new linear turbine prototype with inclined blades was designed. Key words: water power system, blade-chain devices, linear turbines

  12. EFFECT OF EXTRACTIVES AND CARBONIZATION TEMPERATURE ON ENERGY CHARACTERISTICS OF WOOD WASTE IN AMAZON RAINFOREST

    Directory of Open Access Journals (Sweden)

    Jordão Cabral Moulin

    2017-06-01

    Full Text Available The objective of this study was to evaluate the effect of extractives soluble in hot water, besides final carbonization temperatures, on the gravimetric yield and properties of charcoal for waste of three native forest species from the Amazon region. Waste cuttings of Ipé, Grapia and Maçaranduba species, from the machine processing for joinery of a company in the State of Pará, were used. Carbonization was carried out in an adapted electric furnace with a heating rate of 1.67°C min-1 and final temperatures of 500, 600 and 700°C. The waste was carbonized fresh after extraction in hot water to remove extractives. Gravimetric yields were analyzed, as well as chemical features and high heating value. In the evaluation of the experiment, arranged in a factorial scheme with three factors (species x temperature x material with and without extraction, and Principal Component Analysis used too. The presence of extractives (soluble in hot water from wood waste had little influence on the gravimetric yield and immediate chemical composition of charcoal; however, it showed a greater high heating value and lower contents of hydrogen and nitrogen. The increase in the final carbonization temperature reduced the gravimetric yield in charcoal, the content of volatile materials and hydrogen, with a higher content of fixed carbon, carbon and high heating value. The treatments with the best energy characteristics were obtained from Ipé and Maçaranduba charcoals with extractives produced at 600°C, in addition to Ipê and Maçaranduba charcoals with and without extractives obtained at 700°C.

  13. Energy from CO2 using capacitive electrodes – A model for energy extraction cycles

    NARCIS (Netherlands)

    Paz-García, J.M.; Dykstra, J.E.; Biesheuvel, P.M.; Hamelers, H.V.M.

    2015-01-01

    A model is presented for the process of harvesting electrical energy from CO2 emissions using capacitive cells. The principle consists of controlling the mixing process of a concentrated CO2 gas stream with a dilute CO2 gas stream (as, for example, exhaust gas and air), thereby converting part of

  14. Final Report - Energy Reduction and Advanced Water Removal via Membrane Solvent Extraction Technology

    Energy Technology Data Exchange (ETDEWEB)

    Reed, John; Fanselow, Dan; Abbas, Charles; Sammons, Rhea; Kinchin, Christopher

    2014-08-06

    3M and Archer Daniels Midland (ADM) collaborated with the U.S. Department of Energy (DOE) to develop and demonstrate a novel membrane solvent extraction (MSE) process that can substantially reduce energy and water consumption in ethanol production, and accelerate the fermentation process. A cross-flow membrane module was developed, using porous membrane manufactured by 3M. A pilot process was developed that integrates fermentation, MSE and vacuum distillation. Extended experiments of 48-72 hours each were conducted to develop the process, verify its performance and begin establishing commercial viability.

  15. Extracting the σ-term from low-energy pion-nucleon scattering

    Science.gov (United States)

    Ruiz de Elvira, Jacobo; Hoferichter, Martin; Kubis, Bastian; Meißner, Ulf-G.

    2018-02-01

    We present an extraction of the pion-nucleon (π N) scattering lengths from low-energy π N scattering, by fitting a representation based on Roy-Steiner equations to the low-energy data base. We show that the resulting values confirm the scattering-length determination from pionic atoms, and discuss the stability of the fit results regarding electromagnetic corrections and experimental normalization uncertainties in detail. Our results provide further evidence for a large π N σ-term, {σ }π N=58(5) {{MeV}}, in agreement with, albeit less precise than, the determination from pionic atoms.

  16. A Rigorous Treatment of Energy Extraction from a Rotating Black Hole

    Science.gov (United States)

    Finster, F.; Kamran, N.; Smoller, J.; Yau, S.-T.

    2009-05-01

    The Cauchy problem is considered for the scalar wave equation in the Kerr geometry. We prove that by choosing a suitable wave packet as initial data, one can extract energy from the black hole, thereby putting supperradiance, the wave analogue of the Penrose process, into a rigorous mathematical framework. We quantify the maximal energy gain. We also compute the infinitesimal change of mass and angular momentum of the black hole, in agreement with Christodoulou’s result for the Penrose process. The main mathematical tool is our previously derived integral representation of the wave propagator.

  17. The effect of pulse current on energy saving during Electrochemical Chloride Extraction (ECE) in concrete

    DEFF Research Database (Denmark)

    Sun, Tian R.; Geiker, Mette R.; Ottosen, Lisbeth M.

    2012-01-01

    Energy consumption is a factor influencing the cost of Electrochemical Chloride Extraction (ECE) in concrete. The aims of this work were to investigate the possibility for energy saving when using a pulsed electric field during ECE and the effect of the pulsed current on removal of chloride. Four...... experiments with artificially polluted concrete under same charge transfer were conducted. Results showed that the energy consumption was decreased 15% by pulse current in experiments with 0.2 mA/cm2 current density, which was higher than that of 0.1 mA/cm2 experiments with a decrease of 9.6%. When comparing...... the voltage drop at different parts of the experimental cells, it was found that the voltage drop of the area across the concrete was the major contributor to energy consumption, and results indicated that the pulse current could decrease the voltage drop of this part by re-distribution of ions in pore fluid...

  18. Energy extraction system using dual-capacitor switching for quench protection of HTS magnet

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Yo Jong; Song, Seung Hyun; Jeon, Hae Ryong; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of); Lee, Woo Seung [JH ENGINEERING CO., LTD., Anyang (Korea, Republic of); Kang, Hyoung Ku [Korea National University of Transportation, Chungju (Korea, Republic of)

    2017-09-15

    The superconducting magnets have a large inductance as well as high operating current. Therefore, mega-joule scale energy can be stored in the magnet. The energy stored in the magnet is sufficient to damage the magnet when a quench occurs. Quench heater and dump resistor can be used to protect the magnet. However, using quench heater to create quench resistors through heat transfer can be slower than instantly switching resistors. Also, electrical short, overheating and breakdown can occur due to quench heater. Moreover, the number of dump resistor should be limited to avoid large terminal voltage. Therefore, in this paper, we propose a quench protection method for extracting the energy stored in a magnet by charging and discharging energy through a capacitor switching without increasing resistance. The simulation results show that the proposed system has a faster current decay within the allowable voltage level.

  19. Energy extraction system using dual-capacitor switching for quench protection of HTS magnet

    International Nuclear Information System (INIS)

    Chi, Yo Jong; Song, Seung Hyun; Jeon, Hae Ryong; Ko, Tae Kuk; Lee, Woo Seung; Kang, Hyoung Ku

    2017-01-01

    The superconducting magnets have a large inductance as well as high operating current. Therefore, mega-joule scale energy can be stored in the magnet. The energy stored in the magnet is sufficient to damage the magnet when a quench occurs. Quench heater and dump resistor can be used to protect the magnet. However, using quench heater to create quench resistors through heat transfer can be slower than instantly switching resistors. Also, electrical short, overheating and breakdown can occur due to quench heater. Moreover, the number of dump resistor should be limited to avoid large terminal voltage. Therefore, in this paper, we propose a quench protection method for extracting the energy stored in a magnet by charging and discharging energy through a capacitor switching without increasing resistance. The simulation results show that the proposed system has a faster current decay within the allowable voltage level

  20. Energy-correction photon counting pixel for photon energy extraction under pulse pile-up

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Daehee; Park, Kyungjin; Lim, Kyung Taek; Cho, Gyuseong, E-mail: gscho@kaist.ac.kr

    2017-06-01

    A photon counting detector (PCD) has been proposed as an alternative solution to an energy-integrating detector (EID) in medical imaging field due to its high resolution, high efficiency, and low noise. The PCD has expanded to variety of fields such as spectral CT, k-edge imaging, and material decomposition owing to its capability to count and measure the number and the energy of an incident photon, respectively. Nonetheless, pulse pile-up, which is a superimposition of pulses at the output of a charge sensitive amplifier (CSA) in each PC pixel, occurs frequently as the X-ray flux increases due to the finite pulse processing time (PPT) in CSAs. Pulse pile-up induces not only a count loss but also distortion in the measured X-ray spectrum from each PC pixel and thus it is a main constraint on the use of PCDs in high flux X-ray applications. To minimize these effects, an energy-correction PC (ECPC) pixel is proposed to resolve pulse pile-up without cutting off the PPT by adding an energy correction logic (ECL) via a cross detection method (CDM). The ECPC pixel with a size of 200×200 µm{sup 2} was fabricated by using a 6-metal 1-poly 0.18 µm CMOS process with a static power consumption of 7.2 μW/pixel. The maximum count rate of the ECPC pixel was extended by approximately three times higher than that of a conventional PC pixel with a PPT of 500 nsec. The X-ray spectrum of 90 kVp, filtered by 3 mm Al filter, was measured as the X-ray current was increased using the CdTe and the ECPC pixel. As a result, the ECPC pixel dramatically reduced the energy spectrum distortion at 2 Mphotons/pixel/s when compared to that of the ERCP pixel with the same 500 nsec PPT.

  1. Thermal evolution of magma reservoirs in the shallow crust and incidence on magma differentiation: the St-Jean-du-Doigt layered intrusion (Brittany, France)

    Science.gov (United States)

    Barboni, M.; Bussy, F.; Ovtcharova, M.; Schoene, B.

    2009-12-01

    .5m/y. Extraction of differentiated residual liquids might eventually take place and mix with newly injected magma as documented in active syn-emplacement shear-zones. These low-pressure differentiated liquids can potentially contribute to subaerial volcanic activity along the major shear-zones.

  2. Magma wagging and whirling in volcanic conduits

    Science.gov (United States)

    Liao, Yang; Bercovici, David; Jellinek, Mark

    2018-02-01

    Seismic tremor characterized by 0.5-7 Hz ground oscillations commonly occur before and during eruptions at silicic volcanoes with widely ranging vent geometries and edifice structures. The ubiquitous characteristics of this tremor imply that its causes are potentially common to silicic volcanoes. Here we revisit and extend to three dimensions the magma-wagging model for tremor (Jellinek and Bercovici, 2011; Bercovici et al., 2013), wherein a stiff magma column rising in a vertical conduit oscillates against a surrounding foamy annulus of bubbly magma, giving rise to tremor. While prior studies were restricted to two-dimensional lateral oscillations, here we explore three-dimensional motion and additional modes of oscillations. In the absence of viscous damping, the magma column undergoes 'whirling' motion: the center of each horizontal section of the column traces an elliptical trajectory. In the presence of viscous effect we identify new 'coiling' and 'uncoiling' column bending shapes with relatively higher and comparable rates of dissipation to the original two-dimensional magma wagging model. We also calculate the seismic P-wave response of the crustal material around the volcanic conduit to the new whirling motions and propose seismic diagnostics for different wagging patterns using the time-lag between seismic stations. We test our model by analyzing pre-eruptive seismic data from the 2009 eruption of Redoubt Volcano. In addition to suggesting that the occurrence of elliptical whirling motion more than 1 week before the eruption, our analysis of seismic time-lags also implies that the 2009 eruption was accompanied by qualitative changes in the magma wagging behavior including fluctuations in eccentricity and a reversal in the direction of elliptical whirling motion when the eruption was immediately impending.

  3. Energy and tannin extract supplementation for dairy cows on annual winter pastures

    Directory of Open Access Journals (Sweden)

    Tiago Pansard Alves

    2017-05-01

    Full Text Available Energy supplementation can increase the consumption of metabolizable energy and substrate for microbial growth, while condensed tannins aid in increasing the duodenal flow of foodborne metabolizable proteins. The objective of this study was to evaluate the effects of energy supplementation and the inclusion of tannin extract (TE from Acacia mearnsii (Weibull Black, Tanac S. A., Montenegro, Brazil on the production performance of dairy cows grazing on winter pastures. Nine multiparous Holstein cows in mid lactation were distributed in a 3 × 3 Latin square experimental design over three periods of 28 days (21 adaptation and 7 sampling. The treatments were: without supplementation (WS, supplementation with 4 kg of corn grain (CG, and corn grain + 80 g of tannin extract (TE. The dry matter (DM intake from pastures was similar among treatments, but the consumption of DM of the supplement was higher in the CG treatment than that in the TE treatment. The total DM intake was higher for the supplemented animals (17.3 kg?day-1 than that for the unsupplemented animals (14.9 kg?day-1 and in the TE treatment (17.7 kg?day-1 than in the CG treatment (16.7 kg day-1. Milk production increased from the unsupplemented to the supplemented animals (20.9 to 23.5 kg, respectively, while the content of urea N in the milk decreased (12.6 to 10.5 mg?100 mL-1, respectively. There were no differences in milk production or content of milk urea N between the CG and TE treatments. Energy supplementation is a tool for improving the nutritional profile and the performance of dairy cows in mid lactation grazing on annual winter pastures, while tannin extract aids in improving the energy balance.

  4. Reaction of Rhyolitic Magma to its Interception by the IDDP-1 Well, Krafla, 2009

    Science.gov (United States)

    Saubin, É.; Kennedy, B.; Tuffen, H.; Villeneuve, M.; Watson, T.; Nichols, A. R.; Schipper, I.; Cole, J. W.; Mortensen, A. K.; Zierenberg, R. A.

    2017-12-01

    The unexpected encounter of rhyolitic magma during IDDP-1 geothermal borehole drilling at Krafla, Iceland in 2009, temporarily created the world's hottest geothermal well. This allowed new questions to be addressed. i) How does magma react to drilling? ii) Are the margins of a magma chamber suitable for long-term extraction of supercritical fluids? To investigate these questions, we aim to reconstruct the degassing and deformation behaviour of the enigmatic magma by looking for correlations between textures in rhyolitic material retrieved from the borehole and the recorded drilling data. During drilling, difficulties were encountered in two zones, at 2070 m and below 2093 m depth. Drilling parameters are consistent with the drill bit encountering a high permeability zone and the contact zone of a magma chamber, respectively. Magma was intercepted three times between 2101-2104.4 m depth, which culminated in an increase in standpipe pressure followed by a decrease in weight on bit interpreted as representing the ascent of magma within the borehole. Circulation returned one hour after the last interception, carrying cuttings of glassy particles, felsite with granophyre and contaminant clasts from drilling, which were sampled as a time-series for the following 9 hours. The nature of glassy particles in this time-series varied through time, with a decrease in the proportion of vesicular clasts and a commensurate increase in dense glassy clasts, transitioning from initially colourless to brown glass. Componentry data show a sporadic decrease in felsite (from 34 wt. %), an increase in glassy particles during the first two hours (from 63 wt. % to 94 wt. %) and an increase in contaminant clasts towards the end of the cutting retrieval period. These temporal variations are probably related to the magma body architecture and interactions with the borehole. Transition from vesicular to dense clasts suggests a change in the degassing process that could be related to an early

  5. Artificial magma and applications of the blasting technique

    Energy Technology Data Exchange (ETDEWEB)

    Ichioka, K [Chugoku Kaki KK, Japan

    1974-01-01

    Artifical magma is discussed. Solid magma is a high temperature source and fluid magma is also a heat carrier. Iron ores are examples of solid magma, silica-borate is an example of a hydrophobic heat carrier magma assuming a liquid phase at 600/sup 0/C, and S, Ag, Pb, etc. are also examples of heat carrier magma. In addition to these examples, basic salts such as NaNO/sub 3/, KNO/sub 3/, NaCl, CaCl, KCl, BaCl, and Na/sub 4/B/sub 4/O/sub 7/ can be used as artifical magma. These are artifical magmas or heat mediums capable of capturing geothermal heat when circulated inside volcanoes. The blasting technique's applications in geothermal wells are also discussed. The technique can be used to expand a well's diameter, repair the well bottom, regenerate old wells, clean wells, or cut steel pipe. Two figures and one table are provided.

  6. Microalgae based biorefinery: evaluation of oil extraction methods in terms of efficiency, costs, toxicity and energy in lab-scale

    Directory of Open Access Journals (Sweden)

    Ángel Darío González-Delgado

    2013-06-01

    Full Text Available Several alternatives of microalgal metabolites extraction and transformation are being studied for achieving the total utilization of this energy crop of great interest worldwide. Microalgae oil extraction is a key stage in microalgal biodiesel production chains and their efficiency affects significantly the global process efficiency. In this study, a comparison of five oil extraction methods in lab-scale was made taking as additional parameters, besides extraction efficiency, the costs of method performing, energy requirements, and toxicity of solvents used, in order to elucidate the convenience of their incorporation to a microalgae-based topology of biorefinery. Methods analyzed were Solvent extraction assisted with high speed homogenization (SHE, Continuous reflux solvent extraction (CSE, Hexane based extraction (HBE, Cyclohexane based extraction (CBE and Ethanol-hexane extraction (EHE, for this evaluation were used the microalgae strains Nannochloropsis sp., Guinardia sp., Closterium sp., Amphiprora sp. and Navicula sp., obtained from a Colombian microalgae bioprospecting. In addition, morphological response of strains to oil extraction methods was also evaluated by optic microscopy. Results shows that although there is not a unique oil extraction method which excels in all parameters evaluated, CSE, SHE and HBE appears as promising alternatives, while HBE method is shown as the more convenient for using in lab-scale and potentially scalable for implementation in a microalgae based biorefinery

  7. Loki Patera: A Magma Sea Story

    Science.gov (United States)

    Veeder, G. J.; Matson, D. L.; Rathbun, A. G.

    2005-01-01

    We consider Loki Patera on Io as the surface expression of a large uniform body of magma. Our model of the Loki magma sea is some 200 km across; larger than a lake but smaller than an ocean. The depth of the magma sea is unknown, but assumed to be deep enough that bottom effects can be ignored. Edge effects at the shore line can be ignored to first order for most of the interior area. In particular, we take the dark material within Loki Patera as a thin solidified lava crust whose hydrostatic shape follows Io's isostatic surface (approx. 1815 km radius of curvature). The dark surface of Loki appears to be very smooth on both regional and local (subresolution) scales. The thermal contrast between the low and high albedo areas within Loki is consistent with the observed global correlation. The composition of the model magma sea is basaltic and saturated with dissolved SO2 at depth. Its average, almost isothermal, temperature is at the liquidus for basalt. Additional information is included in the original extended abstract.

  8. Probing magma reservoirs to improve volcano forecasts

    Science.gov (United States)

    Lowenstern, Jacob B.; Sisson, Thomas W.; Hurwitz, Shaul

    2017-01-01

    When it comes to forecasting eruptions, volcano observatories rely mostly on real-time signals from earthquakes, ground deformation, and gas discharge, combined with probabilistic assessments based on past behavior [Sparks and Cashman, 2017]. There is comparatively less reliance on geophysical and petrological understanding of subsurface magma reservoirs.

  9. Iron Redox Systematics of Martian Magmas

    Science.gov (United States)

    Righter, K.; Danielson, L.; Martin, A.; Pando, K.; Sutton, S.; Newville, M.

    2011-01-01

    Martian magmas are known to be FeO-rich and the dominant FeO-bearing mineral at many sites visited by the Mars Exploration rovers (MER) is magnetite [1]. Morris et al. [1] propose that the magnetite appears to be igneous in origin, rather than of secondary origin. However, magnetite is not typically found in experimental studies of martian magmatic rocks [2,3]. Magnetite stability in terrestrial magmas is well understood, as are the stability of FeO and Fe2O3 in terrestrial magmas [4,5]. In order to better understand the variation of FeO and Fe2O3, and the stability of magnetite (and other FeO-bearing phases) in martian magmas we have undertaken an experimental study with two emphases. First we document the stability of magnetite with temperature and fO2 in a shergottite bulk composition. Second, we determine the FeO and Fe2O3 contents of the same shergottite bulk composition at 1 bar and variable fO2 at 1250 C, and at variable pressure. These two goals will help define not only magnetite stability, but pyroxene-melt equilibria that are also dependent upon fO2.

  10. Unusual Iron Redox Systematics of Martian Magmas

    Science.gov (United States)

    Danielson, L.; Righter, K.; Pando, K.; Morris, R. V.; Graff, T.; Agresti, D.; Martin, A.; Sutton, S.; Newville, M.; Lanzirotti, A.

    2012-01-01

    Martian magmas are known to be FeO-rich and the dominant FeO-bearing mineral at many sites visited by the Mars Exploration rovers (MER) is magnetite. Morris et al. proposed that the magnetite appears to be igneous in origin, rather than of secondary origin. However, magnetite is not typically found in experimental studies of martian magmatic rocks. Magnetite stability in terrestrial magmas is well understood, as are the stabilities of FeO and Fe2O3 in terrestrial magmas. In order to better understand the variation of FeO and Fe2O3, and the stability of magnetite (and other FeO-bearing phases) in martian magmas, we have undertaken an experimental study with two emphases. First, we determine the FeO and Fe2O3 contents of super- and sub-liquidus glasses from a shergottite bulk composition at 1 bar to 4 GPa, and variable fO2. Second, we document the stability of magnetite with temperature and fO2 in a shergottite bulk composition.

  11. Quantum measurement information as a key to energy extraction from local vacuums

    International Nuclear Information System (INIS)

    Hotta, Masahiro

    2008-01-01

    In this paper, a protocol is proposed in which energy extraction from local vacuum states is possible by using quantum measurement information for the vacuum state of quantum fields. In the protocol, Alice, who stays at a spatial point, excites the ground state of the fields by a local measurement. Consequently, wave packets generated by Alice's measurement propagate the vacuum to spatial infinity. Let us assume that Bob stays away from Alice and fails to catch the excitation energy when the wave packets pass in front of him. Next Alice announces her local measurement result to Bob by classical communication. Bob performs a local unitary operation depending on the measurement result. In this process, positive energy is released from the fields to Bob's apparatus of the unitary operation. In the field systems, wave packets are generated with negative energy around Bob's location. Soon afterwards, the negative-energy wave packets begin to chase after the positive-energy wave packets generated by Alice and form loosely bound states.

  12. Novel high efficient speed sensorless controller for maximum power extraction from wind energy conversion systems

    International Nuclear Information System (INIS)

    Fathabadi, Hassan

    2016-01-01

    Highlights: • Novel sensorless MPPT technique without drawbacks of other sensor/sensorless methods. • Tracking the actual MPP of WECSs, no tracking the MPP of their wind turbines. • Actually extracting the highest output power from WECSs. • Novel MPPT technique having the MPPT efficiency more than 98.5% for WECSs. • Novel MPPT technique having short convergence time for WECSs. - Abstract: In this study, a novel high accurate sensorless maximum power point tracking (MPPT) method is proposed. The technique tracks the actual maximum power point of a wind energy conversion system (WECS) at which maximum output power is extracted from the system, not the maximum power point of its wind turbine at which maximum mechanical power is obtained from the turbine, so it actually extracts the highest output power from the system. The technique only uses input voltage and current of the converter used in the system, and neither needs any speed sensors (anemometer and tachometer) nor has the drawbacks of other sensor/sensorless based MPPT methods. The technique has been implemented as a MPPT controller by constructing a WECS. Theoretical results, the technique performance, and its advantages are validated by presenting real experimental results. The real static-dynamic response of the MPPT controller is experimentally obtained that verifies the proposed MPPT technique high accurately extracts the highest instant power from wind energy conversion systems with the MPPT efficiency of more than 98.5% and a short convergence time that is only 25 s for the constructed system having a total inertia and friction coefficient of 3.93 kg m 2 and 0.014 N m s, respectively.

  13. Magma-poor vs. magma-rich continental rifting and breakup in the Labrador Sea

    Science.gov (United States)

    Gouiza, M.; Paton, D.

    2017-12-01

    Magma-poor and magma-rich rifted margins show distinct structural and stratigraphic geometries during the rift to breakup period. In magma-poor margins, crustal stretching is accommodated mainly by brittle faulting and the formation of wide rift basins shaped by numerous graben and half-graben structures. Continental breakup and oceanic crust accretion are often preceded by a localised phase of (hyper-) extension where the upper mantle is embrittled, serpentinized, and exhumed to the surface. In magma-rich margins, the rift basin is narrow and extension is accompanied by a large magmatic supply. Continental breakup and oceanic crust accretion is preceded by the emplacement of a thick volcanic crust juxtaposing and underplating a moderately thinned continental crust. Both magma-poor and magma-rich rifting occur in response to lithospheric extension but the driving forces and processes are believed to be different. In the former extension is assumed to be driven by plate boundary forces, while in the latter extension is supposed to be controlled by sublithospheric mantle dynamics. However, this view fails in explaining observations from many Atlantic conjugate margins where magma-poor and magma-rich segments alternate in a relatively abrupt fashion. This is the case of the Labrador margin where the northern segment shows major magmatic supply during most of the syn-rift phase which culminate in the emplacement of a thick volcanic crust in the transitional domain along with high density bodies underplating the thinned continental crust; while the southern segment is characterized mainly by brittle extension, mantle seprentinization and exhumation prior to continental breakup. In this work, we use seismic and potential field data to describe the crustal and structural architectures of the Labrador margin, and investigate the tectonic and mechanical processes of rifting that may have controlled the magmatic supply in the different segments of the margin.

  14. The mechanics of shallow magma reservoir outgassing

    Science.gov (United States)

    Parmigiani, A.; Degruyter, W.; Leclaire, S.; Huber, C.; Bachmann, O.

    2017-08-01

    Magma degassing fundamentally controls the Earth's volatile cycles. The large amount of gas expelled into the atmosphere during volcanic eruptions (i.e., volcanic outgassing) is the most obvious display of magmatic volatile release. However, owing to the large intrusive:extrusive ratio, and considering the paucity of volatiles left in intrusive rocks after final solidification, volcanic outgassing likely constitutes only a small fraction of the overall mass of magmatic volatiles released to the Earth's surface. Therefore, as most magmas stall on their way to the surface, outgassing of uneruptible, crystal-rich magma storage regions will play a dominant role in closing the balance of volatile element cycling between the mantle and the surface. We use a numerical approach to study the migration of a magmatic volatile phase (MVP) in crystal-rich magma bodies ("mush zones") at the pore scale. Our results suggest that buoyancy-driven outgassing is efficient over crystal volume fractions between 0.4 and 0.7 (for mm-sized crystals). We parameterize our pore-scale results for MVP migration in a thermomechanical magma reservoir model to study outgassing under dynamical conditions where cooling controls the evolution of the proportion of crystal, gas, and melt phases and to investigate the role of the reservoir size and the temperature-dependent viscoelastic response of the crust on outgassing efficiency. We find that buoyancy-driven outgassing allows for a maximum of 40-50% volatiles to leave the reservoir over the 0.4-0.7 crystal volume fractions, implying that a significant amount of outgassing must occur at high crystal content (>0.7) through veining and/or capillary fracturing.

  15. Io: Loki Patera as a Magma Sea

    Science.gov (United States)

    Matson, Dennis L.; Davies, Ashley Gerard; Veeder, Glenn J.; Rathbun, Julie A.; Johnson, Torrence V.; Castillo, Julie C.

    2006-01-01

    We develop a physical model for Loki Patera as a magma sea. We calculate the total volume of magma moving through the Loki Patera volcanic system every resurfacing cycle (approx.540 days) and the resulting variation in thermal emission. The rate of magma solidification at times reaches 3 x 10(exp 6) kg per second, with a total solidified volume averaging 100 cu km per year. A simulation of gas physical chemistry evolution yields the crust porosity profile and the timescale when it will become dense enough to founder in a manner consistent with observations. The Loki Patera surface temperature distribution shows that different areas are at different life cycle stages. On a regional scale, however, there can be coordinated activity, indicated by the wave of thermal change which progresses from Loki Patera's SW quadrant toward the NE at a rate of approx.1 km per day. Using the observed surface temperature distribution, we test several mechanisms for resurfacing Loki Patera, finding that resurfacing with lava flows is not realistic. Only the crustal foundering process is consistent with observations. These tests also discovered that sinking crust has a 'heat deficit' which promotes the solidification of additional magma onto the sinking plate ("bulking up"). In the limiting case, the mass of sinking material can increase to a mass of approx.3 times that of the foundering plate. With all this solid matter sinking, there is a compensating upward motion in the liquid magma. This can be in excess of 2 m per year. In this manner, solid-liquid convection is occurring in the sea.

  16. An energy-saving opportunity in producing lubricating oil using mixed-solventin simulated Rotary Disc Contacting (RDC) extraction tower

    Energy Technology Data Exchange (ETDEWEB)

    Hatamipour, M.S.; Fakhr Hoseini, S.M.; Tavakkoli, T.; Mehrkesh, A.H. [Chemical Engineering Department, University of Isfahan, Isfahan (Iran)

    2010-05-15

    Industrial processes are the most energy consuming processes in the world. Modification of these processes helps us with controlling the consumption of energy and minimizing energy loss. Changing raw materials is one of the ways through which we can optimize industrial processes. In this paper, a new solvent mixture (furfural + a co-solvent) was used for the extraction of lubricating base oil from lube-oil cut. It was found that the energy consumption of the new solvent mixture for obtaining a product with the same quality was much lower than the original solvent. By using this new solvent mixture, the operating temperature of the top of tower was reduced by 30 K. This leads to a high reduction in energy consumption in extraction of aromatics from lube oil. At our new extraction process by means of using new solvent mixture, the maximum energy saving was 38% per cubic meter of produced raffinate. (author)

  17. Macroalgae-Derived Biofuel: A Review of Methods of Energy Extraction from Seaweed Biomass

    Directory of Open Access Journals (Sweden)

    John J. Milledge

    2014-11-01

    Full Text Available The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, but as yet there is no successful economically viable commercial system producing biofuel. However, the majority of the research has focused on producing fuels from microalgae rather than from macroalgae. This article briefly reviews the methods by which useful energy may be extracted from macroalgae biomass including: direct combustion, pyrolysis, gasification, trans-esterification to biodiesel, hydrothermal liquefaction, fermentation to bioethanol, fermentation to biobutanol and anaerobic digestion, and explores technical and engineering difficulties that remain to be resolved.

  18. Modeling Evaluation of Tidal Stream Energy and the Impacts of Energy Extraction on Hydrodynamics in the Taiwan Strait

    Directory of Open Access Journals (Sweden)

    Ming-Hsi Hsu

    2013-04-01

    Full Text Available Tidal stream speeds in straits are accelerated because of geographic and bathymetric features. For instance, narrow channels and shallows can cause high tidal stream energy. In this study, water level and tidal current were simulated using a three-dimensional semi-implicit Eulerian-Lagrangian finite-element model to investigate the complex tidal characteristics in the Taiwan Strait and to determine potential locations for harnessing tidal stream energy. The model was driven by nine tidal components (M2, S2, N2, K2, K1, O1, P1, Q1, and M4 at open boundaries. The modeling results were validated with the measured data, including water level and tidal current. Through the model simulations, we found that the highest tidal currents occurred at the Penghu Channel in the Taiwan Strait. The Penghu Channel is an appropriate location for the deployment of a tidal turbine array because of its deep and flat bathymetry. The impacts of energy extraction on hydrodynamics were assessed by considering the momentum sink approach. The simulated results indicate that only minimal impacts would occur on water level and tidal current in the Taiwan Strait if a turbine array (55 turbines was installed in the Penghu Channel.

  19. Deep magma transport at Kilauea volcano, Hawaii

    Science.gov (United States)

    Wright, T.L.; Klein, F.W.

    2006-01-01

    The shallow part of Kilauea's magma system is conceptually well-understood. Long-period and short-period (brittle-failure) earthquake swarms outline a near-vertical magma transport path beneath Kilauea's summit to 20 km depth. A gravity high centered above the magma transport path demonstrates that Kilauea's shallow magma system, established early in the volcano's history, has remained fixed in place. Low seismicity at 4-7 km outlines a storage region from which magma is supplied for eruptions and intrusions. Brittle-failure earthquake swarms shallower than 5 km beneath the rift zones accompany dike emplacement. Sparse earthquakes extend to a decollement at 10-12 km along which the south flank of Kilauea is sliding seaward. This zone below 5 km can sustain aseismic magma transport, consistent with recent tomographic studies. Long-period earthquake clusters deeper than 40 km occur parallel to and offshore of Kilauea's south coast, defining the deepest seismic response to magma transport from the Hawaiian hot spot. A path connecting the shallow and deep long-period earthquakes is defined by mainshock-aftershock locations of brittle-failure earthquakes unique to Kilauea whose hypocenters are deeper than 25 km with magnitudes from 4.4 to 5.2. Separation of deep and shallow long-period clusters occurs as the shallow plumbing moves with the volcanic edifice, while the deep plumbing is centered over the hotspot. Recent GPS data agrees with the volcano-propagation vector from Kauai to Maui, suggesting that Pacific plate motion, azimuth 293.5?? and rate of 7.4 cm/yr, has been constant over Kilauea's lifetime. However, volcano propagation on the island of Hawaii, azimuth 325??, rate 13 cm/yr, requires southwesterly migration of the locus of melting within the broad hotspot. Deep, long-period earthquakes lie west of the extrapolated position of Kilauea backward in time along a plate-motion vector, requiring southwesterly migration of Kilauea's magma source. Assumed ages of 0

  20. Effect of coffee reduction on constituent concentration in an energy-efficient process of ultrasonic extraction

    Directory of Open Access Journals (Sweden)

    Wang Cheng-Chi

    2015-01-01

    Full Text Available Coffee is one of the popular beverage; its constituents include caffeine, oxidation resistant aromatic constituents, protein, tannin, and fat. It is indicated in literatures that a proper amount of coffee stimulates the brain and enhances memory, but excessive coffee causes negative results, such as coronary artery disease, high blood pressure, heart disease and kidney disease. This study used high-performance ultrasonic process to discuss the effect of pulverized coffee reduction on the constituent concentration. It further compared the constituent concentrations obtained in different extraction periods. The experimental results show that the coffee aroma constituents can be extracted effectively by ultrasonic process without any organic solvent, and the constituent concentration does not decrease with the addition of pulverized coffee. Therefore, the consumption of pulverized coffee can be reduced greatly by using the proposed. The time of extraction process can be shortened, so as to save energy. The most important point is to reduce the enterprises manufacturing cost and to increase the profit.

  1. Radiator Enhanced Geothermal System - A Revolutionary Method for Extracting Geothermal Energy

    Science.gov (United States)

    Karimi, S.; Marsh, B. D.; Hilpert, M.

    2017-12-01

    A new method of extracting geothermal energy, the Radiator Enhanced Geothermal System (RAD-EGS) has been developed. RAD-EGS attempts to mimic natural hydrothermal systems by 1) generating a vertical vane of artificially produced high porosity/permeability material deep in a hot sedimentary aquifer, 2) injecting water at surface temperatures to the bottom of the vane, where the rock is the hottest, 3) extracting super-heated water at the top of the vane. The novel RAD-EGS differs greatly from the currently available Enhanced Geothermal Systems in vane orientation, determined in the governing local crustal stress field by Shmax and Sl (meaning it is vertical), and in the vane location in a hot sedimentary aquifer, which naturally increases the longevity of the system. In this study, we explore several parameters regimes affecting the water temperature in the extraction well, keeping in mind that the minimum temperature of the extracted water has to be 150 °C in order for a geothermal system to be commercially viable. We used the COMSOL finite element package to simulate coupled heat and fluid transfer within the RAD-EGS model. The following geologic layers from top to bottom are accounted for in the model: i) confining upper layer, ii) hot sedimentary aquifer, and iii) underlying basement rock. The vane is placed vertically within the sedimentary aquifer. An injection well and an extraction well are also included in the simulation. We tested the model for a wide range of various parameters including background heat flux, thickness of geologic layers, geometric properties of the vane, diameter and location of the wells, fluid flow within the wells, regional hydraulic gradient, and permeability and porosity of the layers. The results show that among the aforementioned parameters, background heat flux and the depth of vane emplacement are highly significant in determining the level of commercial viability of the geothermal system. These results indicate that for the

  2. Magma Dynamics in Dome-Building Volcanoes

    Science.gov (United States)

    Kendrick, J. E.; Lavallée, Y.; Hornby, A. J.; Schaefer, L. N.; Oommen, T.; Di Toro, G.; Hirose, T.

    2014-12-01

    The frequent and, as yet, unpredictable transition from effusive to explosive volcanic behaviour is common to active composite volcanoes, yet our understanding of the processes which control this evolution is poor. The rheology of magma, dictated by its composition, porosity and crystal content, is integral to eruption behaviour and during ascent magma behaves in an increasingly rock-like manner. This behaviour, on short timescales in the upper conduit, provides exceptionally dynamic conditions that favour strain localisation and failure. Seismicity released by this process can be mimicked by damage accumulation that releases acoustic signals on the laboratory scale, showing that the failure of magma is intrinsically strain-rate dependent. This character aids the development of shear zones in the conduit, which commonly fracture seismogenically, producing fault surfaces that control the last hundreds of meters of ascent by frictional slip. High-velocity rotary shear (HVR) experiments demonstrate that at ambient temperatures, gouge behaves according to Byerlee's rule at low slip velocities. At rock-rock interfaces, mechanical work induces comminution of asperities and heating which, if sufficient, may induce melting and formation of pseudotachylyte. The viscosity of the melt, so generated, controls the subsequent lubrication or resistance to slip along the fault plane thanks to non-Newtonian suspension rheology. The bulk composition, mineralogy and glass content of the magma all influence frictional behaviour, which supersedes buoyancy as the controlling factor in magma ascent. In the conduit of dome-building volcanoes, the fracture and slip processes are further complicated: slip-rate along the conduit margin fluctuates. The shear-thinning frictional melt yields a tendency for extremely unstable slip thanks to its pivotal position with regard to the glass transition. This thermo-kinetic transition bestows the viscoelastic melt with the ability to either flow or

  3. Optimum Energy Extraction from Coherent Vortex Rings Passing Tangentially Over Flexible Plates

    Science.gov (United States)

    Pirnia, Alireza; Browning, Emily A.; Peterson, Sean D.; Erath, Byron D.

    2017-11-01

    Coherent vortical structures can incite self-sustained oscillations in flexible membranes. This concept has recently gained interest for energy extraction from ambient environments. In this study the special case of a vortex ring passing tangentially over a cantilevered flexible plate is investigated. This problem is governed by the Kirchhoff-Love plate equation, which can be expressed in terms of a non-dimensional mass parameter of the plate, non-dimensional pressure loading induced by the vortex ring, and a Strouhal (St) number which expresses the duration of pressure loading relative to the period of plate oscillation. For a plate with a fixed mass parameter immersed in a fluid environment, the St number specifies the beam dynamics and the energy exchange process. The aim of this study is to identify the St number corresponding to maximum energy exchange between plates and vortex rings. The energy exchange process between the vortex ring and the plate is investigated over a range of 0.3 transfer is reported in each case and an empirical correlation is provided for predictive purposes. Supported by the National Science Foundation (NSF) under Grant No. CBET-1511761, and the Natural Sciences and Engineering Research Council of Canada (NSERC), under Grant No. 05778-2015.

  4. Novel views on the extraction of energy from wind. Heat generation and terrain concentration

    Energy Technology Data Exchange (ETDEWEB)

    Corten, G.P. [ECN Wind, Petten (Netherlands)

    2001-09-01

    First it will be shown that an actuator disk operating in wind turbine mode extracts more energy from the fluid than can be transferred into useful energy. At the Lanchester-Betz limit the decrease of the kinetic energy in the wind is converted by 2/3 into useful power and by 1/3 into heat. Behind the wind turbine the outer flow and the flow that has passed the actuator disk will mix. In this process momentum is conserved but part of the kinetic energy will dissipate in heat via viscous shear. Second we will explain that the classic site calibration in complex terrain has no physical basis. The concentration will depend on the wind direction and this implies that a turbine (pitch- or stall regulated) is expected to have multiple power levels depending on the wind direction under such circumstances. These multiple power levels are expected in particular below rated wind speed. This analysis is put forward in appendix A. 10 refs.

  5. Fuzzy Linguistic Knowledge Based Behavior Extraction for Building Energy Management Systems

    Energy Technology Data Exchange (ETDEWEB)

    Dumidu Wijayasekara; Milos Manic

    2013-08-01

    Significant portion of world energy production is consumed by building Heating, Ventilation and Air Conditioning (HVAC) units. Thus along with occupant comfort, energy efficiency is also an important factor in HVAC control. Modern buildings use advanced Multiple Input Multiple Output (MIMO) control schemes to realize these goals. However, since the performance of HVAC units is dependent on many criteria including uncertainties in weather, number of occupants, and thermal state, the performance of current state of the art systems are sub-optimal. Furthermore, because of the large number of sensors in buildings, and the high frequency of data collection, large amount of information is available. Therefore, important behavior of buildings that compromise energy efficiency or occupant comfort is difficult to identify. This paper presents an easy to use and understandable framework for identifying such behavior. The presented framework uses human understandable knowledge-base to extract important behavior of buildings and present it to users via a graphical user interface. The presented framework was tested on a building in the Pacific Northwest and was shown to be able to identify important behavior that relates to energy efficiency and occupant comfort.

  6. Magma ocean formation due to giant impacts

    Science.gov (United States)

    Tonks, W. B.; Melosh, H. J.

    1993-01-01

    The thermal effects of giant impacts are studied by estimating the melt volume generated by the initial shock wave and corresponding magma ocean depths. Additionally, the effects of the planet's initial temperature on the generated melt volume are examined. The shock pressure required to completely melt the material is determined using the Hugoniot curve plotted in pressure-entropy space. Once the melting pressure is known, an impact melting model is used to estimate the radial distance melting occurred from the impact site. The melt region's geometry then determines the associated melt volume. The model is also used to estimate the partial melt volume. Magma ocean depths resulting from both excavated and retained melt are calculated, and the melt fraction not excavated during the formation of the crater is estimated. The fraction of a planet melted by the initial shock wave is also estimated using the model.

  7. Illuminating magma shearing processes via synchrotron imaging

    Science.gov (United States)

    Lavallée, Yan; Cai, Biao; Coats, Rebecca; Kendrick, Jackie E.; von Aulock, Felix W.; Wallace, Paul A.; Le Gall, Nolwenn; Godinho, Jose; Dobson, Katherine; Atwood, Robert; Holness, Marian; Lee, Peter D.

    2017-04-01

    Our understanding of geomaterial behaviour and processes has long fallen short due to inaccessibility into material as "something" happens. In volcanology, research strategies have increasingly sought to illuminate the subsurface of materials at all scales, from the use of muon tomography to image the inside of volcanoes to the use of seismic tomography to image magmatic bodies in the crust, and most recently, we have added synchrotron-based x-ray tomography to image the inside of material as we test it under controlled conditions. Here, we will explore some of the novel findings made on the evolution of magma during shearing. These will include observations and discussions of magma flow and failure as well as petrological reaction kinetics.

  8. Yamato 980459: Crystallization of Martian Magnesian Magma

    Science.gov (United States)

    Koizumi, E.; Mikouchi, T.; McKay, G.; Monkawa, A.; Chokai, J.; Miyamoto, M.

    2004-01-01

    Recently, several basaltic shergottites have been found that include magnesian olivines as a major minerals. These have been called olivinephyric shergottites. Yamato 980459, which is a new martian meteorite recovered from the Antarctica by the Japanese Antarctic expedition, is one of them. This meteorite is different from other olivine-phyric shergottites in several key features and will give us important clues to understand crystallization of martian meteorites and the evolution of Martian magma.

  9. Lithium enrichment in intracontinental rhyolite magmas leads to Li deposits in caldera basins.

    Science.gov (United States)

    Benson, Thomas R; Coble, Matthew A; Rytuba, James J; Mahood, Gail A

    2017-08-16

    The omnipresence of lithium-ion batteries in mobile electronics, and hybrid and electric vehicles necessitates discovery of new lithium resources to meet rising demand and to diversify the global lithium supply chain. Here we demonstrate that lake sediments preserved within intracontinental rhyolitic calderas formed on eruption and weathering of lithium-enriched magmas have the potential to host large lithium clay deposits. We compare lithium concentrations of magmas formed in a variety of tectonic settings using in situ trace-element measurements of quartz-hosted melt inclusions to demonstrate that moderate to extreme lithium enrichment occurs in magmas that incorporate felsic continental crust. Cenozoic calderas in western North America and in other intracontinental settings that generated such magmas are promising new targets for lithium exploration because lithium leached from the eruptive products by meteoric and hydrothermal fluids becomes concentrated in clays within caldera lake sediments to potentially economically extractable levels.Lithium is increasingly being utilized for modern technology in the form of lithium-ion batteries. Here, using in situ measurements of quartz-hosted melt inclusions, the authors demonstrate that preserved lake sediments within rhyolitic calderas have the potential to host large lithium-rich clay deposits.

  10. The Lunar Magma Ocean: Sharpening the Focus on Process and Composition

    Science.gov (United States)

    Rapp, J. F.; Draper, D. S.

    2014-01-01

    The currently accepted model for the formation of the lunar anorthositic crust is by flotation from a crystallizing lunar magma ocean (LMO) shortly following lunar accretion. Anorthositic crust is globally distributed and old, whereas the mare basalts are younger and derived from a source region that has experienced plagioclase extraction. Several attempts at modelling such a crystallization sequence have been made [e.g. 1, 2], but our ever-increasing knowledge of the lunar samples and surface have raised as many questions as these models have answered. This abstract presents results from our ongoing ex-periments simulating LMO crystallization and address-ing a range of variables. We investigate two bulk com-positions, which span most of the range of suggested lunar bulk compositions, from the refractory element enriched Taylor Whole Moon (TWM) [3] to the more Earth-like Lunar Primitive Upper Mantle (LPUM) [4]. We also investigate two potential crystallization mod-els: Fully fractional, where crystallizing phases are separated from the magma as they form and sink (or float in the case of plagioclase) throughout magma ocean solidification; and a two-step process suggested by [1, 5] with an initial stage of equilibrium crystalliza-tion, where crystals remain entrained in the magma before the crystal burden increases viscosity enough that convection slows and the crystals settle, followed by fractional crystallization. Here we consider the frac-tional crystallization part of this process; the equilibri-um cumulates having been determined by [6].

  11. Optimal control of energy extraction in LES of large wind farms

    Science.gov (United States)

    Meyers, Johan; Goit, Jay; Munters, Wim

    2014-11-01

    We investigate the use of optimal control combined with Large-Eddy Simulations (LES) of wind-farm boundary layer interaction for the increase of total energy extraction in very large ``infinite'' wind farms and in finite farms. We consider the individual wind turbines as flow actuators, whose energy extraction can be dynamically regulated in time so as to optimally influence the turbulent flow field, maximizing the wind farm power. For the simulation of wind-farm boundary layers we use large-eddy simulations in combination with an actuator-disk representation of wind turbines. Simulations are performed in our in-house pseudo-spectral code SP-Wind. For the optimal control study, we consider the dynamic control of turbine-thrust coefficients in the actuator-disk model. They represent the effect of turbine blades that can actively pitch in time, changing the lift- and drag coefficients of the turbine blades. In a first infinite wind-farm case, we find that farm power is increases by approximately 16% over one hour of operation. This comes at the cost of a deceleration of the outer layer of the boundary layer. A detailed analysis of energy balances is presented, and a comparison is made between infinite and finite farm cases, for which boundary layer entrainment plays an import role. The authors acknowledge support from the European Research Council (FP7-Ideas, Grant No. 306471). Simulations were performed on the computing infrastructure of the VSC Flemish Supercomputer Center, funded by the Hercules Foundation and the Flemish Govern.

  12. Ocean Thermal Extractable Energy Visualization- Final Technical Report on Award DE-EE0002664. October 28, 2012

    Energy Technology Data Exchange (ETDEWEB)

    Ascari, Matthew B.; Hanson, Howard P.; Rauchenstein, Lynn; Van Zwieten, James; Bharathan, Desikan; Heimiller, Donna; Langle, Nicholas; Scott, George N.; Potemra, James; Nagurny, N. John; Jansen, Eugene

    2012-10-28

    The Ocean Thermal Extractable Energy Visualization (OTEEV) project focuses on assessing the Maximum Practicably Extractable Energy (MPEE) from the world's ocean thermal resources. MPEE is defined as being sustainable and technically feasible, given today's state-of-the-art ocean energy technology. Under this project the OTEEV team developed a comprehensive Geospatial Information System (GIS) dataset and software tool, and used the tool to provide a meaningful assessment of MPEE from the global and domestic U.S. ocean thermal resources. The OTEEV project leverages existing NREL renewable energy GIS technologies and integrates extractable energy estimated from quality-controlled data and projected optimal achievable energy conversion rates. Input data are synthesized from a broad range of existing in-situ measurements and ground-truthed numerical models with temporal and spatial resolutions sufficient to reflect the local resource. Energy production rates are calculated for regions based on conversion rates estimated for current technology, local energy density of the resource, and sustainable resource extraction. Plant spacing and maximum production rates are then estimated based on a default plant size and transmission mechanisms. The resulting data are organized, displayed, and accessed using a multi-layered GIS mapping tool, http://maps.nrel.gov/mhk_atlas with a user-friendly graphical user interface.

  13. High linear energy transfer degradation studies simulating alpha radiolysis of TRU solvent extraction processes

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, Jeremy [Department of Chemical Engineering and Materials Science - University of California Irvine, 916 Engineering Tower, Irvine, CA, 92697 (United States); Miller, George [Department of Chemistry- University of California Irvine, 2046D PS II, Irvine, CA, 92697 (United States); Nilsson, Mikael [Department of Chemical Engineering and Materials Science - University of California Irvine, 916 Engineering Tower, Irvine, CA, 92697 (United States)

    2013-07-01

    Treatment of used nuclear fuel through solvent extraction separation processes is hindered by radiolytic damage from radioactive isotopes present in used fuel. The nature of the damage caused by the radiation may depend on the radiation type, whether it be low linear energy transfer (LET) such as gamma radiation or high LET such as alpha radiation. Used nuclear fuel contains beta/gamma emitting isotopes but also a significant amount of transuranics which are generally alpha emitters. Studying the respective effects on matter of both of these types of radiation will allow for accurate prediction and modeling of process performance losses with respect to dose. Current studies show that alpha radiation has milder effects than that of gamma. This is important to know because it will mean that solvent extraction solutions exposed to alpha radiation may last longer than expected and need less repair and replacement. These models are important for creating robust, predictable, and economical processes that have strong potential for mainstream adoption on the commercial level. The effects of gamma radiation on solvent extraction ligands have been more extensively studied than the effects of alpha radiation. This is due to the inherent difficulty in producing a sufficient and confluent dose of alpha particles within a sample without leaving the sample contaminated with long lived radioactive isotopes. Helium ion beam and radioactive isotope sources have been studied in the literature. We have developed a method for studying the effects of high LET radiation in situ via {sup 10}B activation and the high LET particles that result from the {sup 10}B(n,a){sup 7}Li reaction which follows. Our model for dose involves solving a partial differential equation representing absorption by 10B of an isentropic field of neutrons penetrating a sample. This method has been applied to organic solutions of TBP and CMPO, two ligands common in TRU solvent extraction treatment processes. Rates

  14. Study of methane hydrate as a future energy resource: low emission extraction and power generation

    Science.gov (United States)

    Chen, L.; Yamada, H.; Kanda, Y.; Sasaki, H.; Okajima, J.; Iga, Y.; Komiya, A.; Maruyama, S.

    2016-08-01

    With the fast increase of world energy consumption in recent years, new and sustainable energy sources are becoming more and more important. Methane Hydrate is one promising candidate for the future energy supply of humankind, due to its vast existence in permafrost regions and near-coast seabed. This study is focused on the effective low emission utilization of methane hydrate from deep seabed. The Nankai Trough of Japan is taken as the target region in this study for methane hydrate extraction and utilization system design. Low emission system and power generation system with CCS (Carbon Capture and Sequestration) processes are proposed and analyzed for production rate and electricity generation efficiency problem study. It is found that the gas production price can reach the current domestic natural gas supply price level if the production rate can be improved. The optimized system is estimated to have power efficiency about 35%. In addition, current development and analysis from micro-to-macro scale methane hydrate production and dissociation dynamics are also discussed into detail in this study.

  15. Effect of acidity on the energy level of curcumin dye extracted from Curcuma longa L

    Energy Technology Data Exchange (ETDEWEB)

    Agustia, Yuda Virgantara, E-mail: yuda.mechanical.engineer@student.uns.ac.id; Suyitno,, E-mail: suyitno@uns.ac.id; Sutanto, Bayu, E-mail: bayu.sutanto@student.uns.ac.id [Department of Mechanical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta (Indonesia); Arifin, Zainal, E-mail: zainal-a@uns.ac.id [Department of Mechanical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta (Indonesia); Department of Mechanical Engineering, Brawijaya University, Malang (Indonesia)

    2016-03-29

    The purpose of this research is to investigate the effect of acidity on the energy level of curcumin dye. The natural dye, curcumin, was synthesized from Curcuma longa L. using a simple extraction technique. The purification of curcumin dye was conducted in a column of chromatography and its characteristics were studied. Next, the purified curcumin dye was added by benzoic acids until various acidities of 3.0, 3.5, 4.0, 4.5, and 5.0. The absorbance spectra and the functionality groups found in the dyes were detected by ultraviolet-visible spectroscopy and Fourier-transform infrared spectroscopy, respectively. Meanwhile, the energy level of the dyes, E{sub HOMO} and E{sub LUMO} was measured by cyclic voltammetry. The best energy level of curcumin dye was achieved at pH 3.5 where E{sub red} = −0.37V, E{sub LUMO} = −4.28 eV, E{sub ox} = 1.15V, E{sub HOMO} = −5.83 eV, and E{sub band} {sub gap} = 1.55 eV. Therefore, the purified curcumin dye added by benzoic acid was promising for sensitizing the dye-sensitized solar cells.

  16. Effect of acidity on the energy level of curcumin dye extracted from Curcuma longa L

    International Nuclear Information System (INIS)

    Agustia, Yuda Virgantara; Suyitno,; Sutanto, Bayu; Arifin, Zainal

    2016-01-01

    The purpose of this research is to investigate the effect of acidity on the energy level of curcumin dye. The natural dye, curcumin, was synthesized from Curcuma longa L. using a simple extraction technique. The purification of curcumin dye was conducted in a column of chromatography and its characteristics were studied. Next, the purified curcumin dye was added by benzoic acids until various acidities of 3.0, 3.5, 4.0, 4.5, and 5.0. The absorbance spectra and the functionality groups found in the dyes were detected by ultraviolet-visible spectroscopy and Fourier-transform infrared spectroscopy, respectively. Meanwhile, the energy level of the dyes, E_H_O_M_O and E_L_U_M_O was measured by cyclic voltammetry. The best energy level of curcumin dye was achieved at pH 3.5 where E_r_e_d = −0.37V, E_L_U_M_O = −4.28 eV, E_o_x = 1.15V, E_H_O_M_O = −5.83 eV, and E_b_a_n_d _g_a_p = 1.55 eV. Therefore, the purified curcumin dye added by benzoic acid was promising for sensitizing the dye-sensitized solar cells.

  17. Effect of acidity on the energy level of curcumin dye extracted from Curcuma longa L.

    Science.gov (United States)

    Agustia, Yuda Virgantara; Suyitno, Arifin, Zainal; Sutanto, Bayu

    2016-03-01

    The purpose of this research is to investigate the effect of acidity on the energy level of curcumin dye. The natural dye, curcumin, was synthesized from Curcuma longa L. using a simple extraction technique. The purification of curcumin dye was conducted in a column of chromatography and its characteristics were studied. Next, the purified curcumin dye was added by benzoic acids until various acidities of 3.0, 3.5, 4.0, 4.5, and 5.0. The absorbance spectra and the functionality groups found in the dyes were detected by ultraviolet-visible spectroscopy and Fourier-transform infrared spectroscopy, respectively. Meanwhile, the energy level of the dyes, EHOMO and ELUMO was measured by cyclic voltammetry. The best energy level of curcumin dye was achieved at pH 3.5 where Ered = -0.37V, ELUMO = -4.28 eV, Eox = 1.15V, EHOMO = -5.83 eV, and Eband gap = 1.55 eV. Therefore, the purified curcumin dye added by benzoic acid was promising for sensitizing the dye-sensitized solar cells.

  18. Wavelet Types Comparison for Extracting Iris Feature Based on Energy Compaction

    Science.gov (United States)

    Rizal Isnanto, R.

    2015-06-01

    Human iris has a very unique pattern which is possible to be used as a biometric recognition. To identify texture in an image, texture analysis method can be used. One of method is wavelet that extract the image feature based on energy. Wavelet transforms used are Haar, Daubechies, Coiflets, Symlets, and Biorthogonal. In the research, iris recognition based on five mentioned wavelets was done and then comparison analysis was conducted for which some conclusions taken. Some steps have to be done in the research. First, the iris image is segmented from eye image then enhanced with histogram equalization. The features obtained is energy value. The next step is recognition using normalized Euclidean distance. Comparison analysis is done based on recognition rate percentage with two samples stored in database for reference images. After finding the recognition rate, some tests are conducted using Energy Compaction for all five types of wavelets above. As the result, the highest recognition rate is achieved using Haar, whereas for coefficients cutting for C(i) < 0.1, Haar wavelet has a highest percentage, therefore the retention rate or significan coefficient retained for Haaris lower than other wavelet types (db5, coif3, sym4, and bior2.4)

  19. Application of microwave energy to speed up the alkaline extraction of humic and fulvic acids from marine sediments

    International Nuclear Information System (INIS)

    Romaris-Hortas, Vanessa; Moreda-Pineiro, Antonio; Bermejo-Barrera, Pilar

    2007-01-01

    The feasibility of microwave energy to speed up the alkaline extraction of humic substances (humic acid, HA, and fulvic acid, FA) from marine sediments has been checked. Extractions were performed by using 20 mL of sodium hydroxide at 0.1 M (two repeated extractions) after an ultrasound-assisted acid pre-treatment of samples to remove the carbonate fraction (ultrasound power at 17 kHz, 10 mL of 6.0 M hydrochloric acid for 15 min). After separation of HA and FA fractions by acidifying with 6 M HCl, the FA fraction (supernatant) was purified by passing the solution through a column of Amberlite XAD-8. Both HA and FA extracts were measured by UV-visible spectrophotometry. All variables affecting the extraction process (sodium hydroxide concentration and volume, ramp and hold times, temperature and number of repeated extractions) have been screened by using a Plackett-Burman design (PBD) as multivariate approach. The variables temperature and number of repeated extractions were the most significant factors (P = 95%) affecting the extraction of both FA and HA from marine sediments. These two variables have led optimum values of 150 deg. C and two repeated extractions. The developed method has been found precise (R.S.D.s of 9% for HA and 12% for FA, for 11 determinations) and its results were comparable in terms of elemental (C, H and N) composition to those obtained after applying methods based on mechanical stirring and ultrasounds assisting. However, higher HA and FA concentrations than those obtained after conventional stirring and ultrasound irradiation were obtained when applying microwave energy. This means a higher efficiency of microwave energy than ultrasounds or mechanical stirring to extract HA and FA fractions from marine sediments. The method was finally applied to different surface marine sediments from the Ria de Arousa estuary

  20. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y., E-mail: thuzhangyu@foxmail.com; Huang, S. L., E-mail: huangsling@tsinghua.edu.cn; Wang, S.; Zhao, W. [State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

    2016-05-15

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  1. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    International Nuclear Information System (INIS)

    Zhang, Y.; Huang, S. L.; Wang, S.; Zhao, W.

    2016-01-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  2. Adakitic magmas: modern analogues of Archaean granitoids

    Science.gov (United States)

    Martin, Hervé

    1999-03-01

    Both geochemical and experimental petrological research indicate that Archaean continental crust was generated by partial melting of an Archaean tholeiite transformed into a garnet-bearing amphibolite or eclogite. The geodynamic context of tholeiite melting is the subject of controversy. It is assumed to be either (1) subduction (melting of a hot subducting slab), or (2) hot spot (melting of underplated basalts). These hypotheses are considered in the light of modern adakite genesis. Adakites are intermediate to felsic volcanic rocks, andesitic to rhyolitic in composition (basaltic members are lacking). They have trondhjemitic affinities (high-Na 2O contents and K 2O/Na 2O˜0.5) and their Mg no. (0.5), Ni (20-40 ppm) and Cr (30-50 ppm) contents are higher than in typical calc-alkaline magmas. Sr contents are high (>300 ppm, until 2000 ppm) and REE show strongly fractionated patterns with very low heavy REE (HREE) contents (Yb≤1.8 ppm, Y≤18 ppm). Consequently, high Sr/Y and La/Yb ratios are typical and discriminating features of adakitic magmas, indicative of melting of a mafic source where garnet and/or hornblende are residual phases. Adakitic magmas are only found in subduction zone environments, exclusively where the subduction and/or the subducted slab are young (subducted and where the adakitic character of the lavas correlates well with the young age of the subducting oceanic lithosphere. In typical subduction zones, the subducted lithosphere is older than 20 Ma, it is cool and the geothermal gradient along the Benioff plane is low such that the oceanic crust dehydrates before it reaches the solidus temperature of hydrated tholeiite. Consequently, the basaltic slab cannot melt. The released large ion lithophile element (LILE)-rich fluids rise up into the mantle wedge, inducing both its metasomatism and partial melting. Afterwards, the residue is made up of olivine+clinopyroxene+orthopyroxene, such that the partial melts are HREE-rich (low La/Yb and Sr

  3. Volcanic systems of Iceland and their magma source

    Science.gov (United States)

    Sigmarsson, Olgeir

    2017-04-01

    -crust boundary or within the crust in magma reservoirs that are still feeding the volcanic systems. A second possible explanation for absence of temporal variations of isotope ratios for a given volcanic system during the last 10 thousand years is that the roots of these systems lie at further depths within the mantle. In that case, extensive fertile source rock of recycled origin with distinct isotope composition must feed the volcanic system and that the melt extraction mechanism from these source regions does not alter (or homogenize) the final melt products. The consequences of these two mechanisms and possible discrimination between them will be discussed.

  4. Dynamic aperture ampersand extraction studies for the SSC High-Energy Booster

    International Nuclear Information System (INIS)

    Chao, A.W.; Dutt, S.K.; Johnson, D.E.; Sen, T.; Yan, Y.

    1990-09-01

    The final booster in the injector chain for the Superconducting Super Collider is a machine approximately twice the size of the Tevatron. Its design includes approximately 450, 15+ m superconducting dipoles. The original designs specified dipoles with a 7 cm coil-winding diameter and an inner horizontal beam-pipe aperture of 55 mm. This dipole design was chosen in order to provide an adequately large good-field aperture for both the beam injection process and for the slow-extraction of high-energy test beams. With the recent decision to increase the Collider dipole coil-winding diameter to 5 cm, the question of the needed HEB aperture was raised. An argument for dipole commonality between the HEB and Collider was developed, and a preliminary examination of a 5 cm HEB dipole was undertaken. This paper reports the results of a detailed study of the injection dynamic aperture for magnet errors corresponding to both a 5 cm and 7 cm dipole. Also studied and reported are preliminary results of the resonant-extraction process for the two magnet designs in question. These studies are in the form of multiparticle computer simulations. The results of the studies indicate that the 7 cm dipole design is consistent with the desired performance requirements for the HEB, while the 5 cm dipole design is marginal. We have not studied intermediate aperture values. 8 refs., 11 figs

  5. Energy extraction from wine dregs by self-sustained burning with fluidized-bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Leu, J.H. [Yu-Da Inst. of Business Technology, Taiwan (China). Dept. of Marketing and Logistics Management; Chung, Y.N.; Pan, T.S.; Chen, C.S. [Dayeh Univ., Taiwan (China). Dept. of Electrical Engineering

    2005-07-01

    Wine dregs typically have moisture contents of between 70 and 80 per cent, and the disposal of wine dregs in Taiwan is both costly and time-consuming. This paper described a method of extracting energy from wine dregs through the use of a pre-drying technique with a fluidized bed technology. A bubble-type fluidized bed combustor was used to combust high moisture Chinese Kaoliang wine lees. The system consisted of an incinerator, a feeding system, a heat recovery system, and an air pollution control system. Results of the experimental study showed that 92.3 per cent combustion was achieved for the wine lees at temperatures of 860 degrees C. Sulfur oxide (SO{sub x}) emissions and nitrogen oxide (NO{sub x}) emissions were negligible. Carbon monoxide (CO) emissions were suppressed to 92 ppm by modulating operating temperatures, axial temperature distributions, and primary and excess air. 3 refs., 3 tabs., 7 figs.

  6. Superradiance energy extraction, black-hole bombs and implications for astrophysics and particle physics

    CERN Document Server

    Brito, Richard; Pani, Paolo

    2015-01-01

    This volume gives a unified picture of the multifaceted subject of superradiance, with a focus on recent developments in the field, ranging from fundamental physics to astrophysics. Superradiance is a radiation enhancement process that involves dissipative systems. With a 60 year-old history, superradiance has played a prominent role in optics, quantum mechanics and especially in relativity and astrophysics. In Einstein's General Relativity, black-hole superradiance is permitted by dissipation at the event horizon, which allows energy extraction from the vacuum, even at the classical level. When confined, this amplified radiation can give rise to strong instabilities known as "blackhole bombs'', which have applications in searches for dark matter, in physics beyond the Standard Model and in analog models of gravity. This book discusses and draws together all these fascinating aspects of superradiance.

  7. AquaMUNE, a brown seaweed extract, improves metabolism, immune response, energy and chelates heavy metals.

    Science.gov (United States)

    1998-01-01

    The National Cancer Institute (NCI) has shown interest in the curative powers of ocean plants, many of which appear to possess powerful anti-inflammatory, antiviral, antimicrobial, antifungal, anticancer, and immuno-suppressive properties. AQUAMune, a brown seaweed extract developed by Aqua-10 Laboratories, has gained marketing rights for use as a nutritional supplement. Research shows that it acts as a receptor blocker for many pathogens, including Salmonella, and is effective against Haemophilus pneumonia. AQUAMune is also reported to inhibit outbreaks of genital herpes. Other marine plants are also showing positive curative powers. Evidence reveals that a red marine algae from the Philippines has selective antitumor properties; and that carageenans, a family of sulfated polysaccharides, appear to have anti-viral capabilities. Seaweeds act as natural chelators of heavy metals that improve metabolism in cells, increase ATP production, body temperature, energy levels, and immune function.

  8. Pulse distortion, energy extraction, and ASE in an HF amplifier with angular multiplexing

    International Nuclear Information System (INIS)

    McGuire, E.J.

    1976-09-01

    It has been proposed that 1 ns pulses can be efficiently extracted from the e-beam initiated HF laser by angular multiplexing, i.e., filling the amplifier with the 1 ns pulses, 1 ns apart in time, each pulse at a slightly different angle; each pulse has an input intensity of 1 W/cm 2 per line and almost fills the amplifier. We have treated this in a one dimensional model, neglecting transverse amplified spontaneous emission. We conclude that the scheme is efficient, and that most of the pulses are amplified but not distorted. The first few pulses are distorted by transient effects and the last pulse has an enhanced tail. The ratio of peak pulse intensity to forward ASE at the output is 10 4 . We then include transverse ASE and find a drastically different situation. ASE saturates the inversion after a short time depending on pulse intensity (4 ns at I/sub o/ = 1 W/cm 2 , 7 ns at I/sub o/ = 100 W/cm 2 ). The saturation time is only weakly dependent on the transverse reflection coefficient. Calculations were done on an amplifier system designed for 10 KJ output. At an incident peak pulse intensity of 10 4 W/cm 2 -line (.77 MW/cm 2 for 77 lines) 2.5 KJ was obtained in amplified pulse energy, i.e., only 6 pulses of the 24 pulse train were fully amplified. The calculations indicate that double passing the pulse train through the amplifier would enhance the energy extracted

  9. Advancing dynamic and thermodynamic modelling of magma oceans

    Science.gov (United States)

    Bower, Dan; Wolf, Aaron; Sanan, Patrick; Tackley, Paul

    2017-04-01

    The techniques for modelling low melt-fraction dynamics in planetary interiors are well-established by supplementing the Stokes equations with Darcy's Law. But modelling high-melt fraction phenomena, relevant to the earliest phase of magma ocean cooling, necessitates parameterisations to capture the dynamics of turbulent flow that are otherwise unresolvable in numerical models. Furthermore, it requires knowledge about the material properties of both solid and melt mantle phases, the latter of which are poorly described by typical equations of state. To address these challenges, we present (1) a new interior evolution model that, in a single formulation, captures both solid and melt dynamics and hence charts the complete cooling trajectory of a planetary mantle, and (2) a physical and intuitive extension of a "Hard Sphere" liquid equation of state (EOS) to describe silicate melt properties for the pressure-temperature (P-T) range of Earth's mantle. Together, these two advancements provide a comprehensive and versatile modelling framework for probing the far-reaching consequences of magma ocean cooling and crystallisation for Earth and other rocky planets. The interior evolution model accounts for heat transfer by conduction, convection, latent heat, and gravitational separation. It uses the finite volume method to ensure energy conservation at each time-step and accesses advanced time integration algorithms by interfacing with PETSc. This ensures it accurately and efficiently computes the dynamics throughout the magma ocean, including within the ultra-thin thermal boundary layers (modelling capabilities. The thermodynamics of mantle melting are represented using a pseudo-one-component model, which retains the simplicity of a standard one-component model while introducing a finite temperature interval for melting (important for multi-component systems). Our new high P-T liquid EOS accurately captures the energetics and physical properties of the partially molten

  10. Geothermal energy worldwide

    International Nuclear Information System (INIS)

    Barbier, Enriko

    1997-01-01

    Geothermal energy, as a natural steam and hot water, has been exploited for decades in order to generate electricity as well as district heating and industrial processes. The present geothermal electrical installed capacity in the world is about 10.000 MWe and the thermal capacity in non-electrical uses is about 8.200 MWt. Electricity is produced with an efficiency of 10-17%, and the cost of the kWh is competitive with conventional energy sources. In the developing countries, where a total installed electrical power is still low, geothermal energy can play a significant role: in El Salvador, for example, 25% of electricity comes from geothermal spring, 20% in the Philippines and 8% in Kenya. Present technology makes it possible to control the environmental impact of geothermal exploitation. Geothermal energy could also be extracted from deep geopressured reservoirs in large sedimentary basins, hot dry rock systems and magma bodies. (author)

  11. Parameter-free extraction of EMCD from an energy-filtered diffraction datacube using multivariate curve resolution

    International Nuclear Information System (INIS)

    Muto, S.; Tatsumi, K.; Rusz, J.

    2013-01-01

    We present a parameter-free method of extraction of the electron magnetic circular dichroism spectra from energy-filtered diffraction patterns measured on a crystalline specimen. The method is based on a multivariate curve resolution technique. The main advantage of the proposed method is that it allows extraction of the magnetic signal regardless of the symmetry and orientation of the crystal, as long as there is a sufficiently strong magnetic component of the signal in the diffraction plane. This method essentially overcomes difficulties in extraction of the EMCD signal caused by complexity of dynamical diffraction effects. - Highlights: ► New method of extraction of EMCD signal using statistical methods (multivariate curve resolution). ► EMCD can be extracted quantitatively regardless of symmetry of crystal or its orientation. ► First principles simulation of EFDIF datacube, including dynamical diffraction effects

  12. Magma fluxes and recurreance rate of eruptions at Nevado de Toluca volcano (Mexico)

    Science.gov (United States)

    Weber, Gregor; Probst, Line; Arce, José L.; Caricchi, Luca

    2017-04-01

    Forecasting the frequency and size of volcanic eruptions is a long-term goal for hazard mitigation. The frequency at which a given crustal magmatic system is driven towards a critical state and the magnitude of the resulting volcanic events are linked to the supply rate of fresh magma, crustal properties, and tectonic setting. Our ability to forecast the recurrence rate of eruptions is hampered by the lack of data on key variables such as the average magma flux locally and globally. The aim of this project is to identify the average magma supply rate and injection frequency for eruptions of different magnitude and eruptive style. We centred our study at Nevado de Toluca in Mexico, a subduction-related volcano with an eruptive history spanning about 1.5 million years of comparatively well documented effusive and explosive eruptions dominantly of dacitic composition. We carry out in-situ high precision zircon geochronology for a sequence of eruptions of different magnitude to obtain a distribution of crystal ages from which average crustal magma fluxes can be calculated. Eruptive fluxes will be constrained by extracting lava flow volumes from a digital elevation model. A combination of whole rock and mineral chemistry will provide quantitative insights on petrogenetic processes and on the frequency at which intensive parameters changed within the magma reservoir before the eruptions. Our results will be integrated in a global database including other volcanic systems and literature data to attempt to identify similarities and differences between magmatic reservoirs feeding volcanic eruptions of different magnitude. The final target of this project is to identify the physical factors controlling the recurrence rate of volcanic eruptions at regional and global scale.

  13. The influence of magma viscosity on convection within a magma chamber

    Science.gov (United States)

    Schubert, M.; Driesner, T.; Ulmer, P.

    2012-12-01

    Magmatic-hydrothermal ore deposits are the most important sources of metals like Cu, Mo, W and Sn and a major resource for Au. It is well accepted that they are formed by the release of magmatic fluids from a batholith-sized magma body. Traditionally, it has been assumed that crystallization-induced volatile saturation (called "second boiling") is the main mechanism for fluid release, typically operating over thousands to tens of thousands of years (Candela, 1991). From an analysis of alteration halo geometries caused by magmatic fluids, Cathles and Shannon (2007) suggested much shorter timescales in the order of hundreds of years. Such rapid release of fluids cannot be explained by second boiling as the rate of solidification scales with the slow conduction of heat away from the system. However, rapid fluid release is possible if convection is assumed within the magma chamber. The magma would degas in the upper part of the magma chamber and volatile poor magma would sink down again. Such, the rates of degassing can be much higher than due to cooling only. We developed a convection model using Navier-Stokes equations provided by the computational fluid dynamics platform OpenFOAM that gives the possibility to use externally derived meshes with complex (natural) geometries. We implemented a temperature, pressure, composition and crystal fraction dependent viscosity (Ardia et al., 2008; Giordano et al., 2008; Moore et al., 1998) and a temperature, pressure, composition dependent density (Lange1994). We found that the new viscosity and density models strongly affect convection within the magma chamber. The dependence of viscosity on crystal fraction has a particularly strong effect as the steep viscosity increase at the critical crystal fraction leads to steep decrease of convection velocity. As the magma chamber is cooling from outside to inside a purely conductive layer is developing along the edges of the magma chamber. Convection continues in the inner part of the

  14. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals.

    Science.gov (United States)

    Zhang, Y; Huang, S L; Wang, S; Zhao, W

    2016-05-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert-Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of wave detection signals.

  15. HYPER (hybrid power extraction reactor): a system for clean nuclear energy

    International Nuclear Information System (INIS)

    Park, W.S.; Shin, U.; Han, S.-J.; Song, T.Y.; Choi, B.H.; Park, C.K.

    2000-01-01

    The Korea Atomic Energy Research Institute (KAERI) has been performing accelerator driven system related research and development (RID) called HYPER (hybrid power extraction reactor) for the transmutation of nuclear waste and energy production through the transmutation process. HYPER program is within the frame work of the national mid and long-term nuclear research plan. KAERI is aiming to develop the elemental technologies for the subcritical transmutation system by the year of 2001 and build a small bench scale test facility (∝5 MW) by the year of 2006. Some major features of HYPER have been developed and employed. On-power fueling concepts are employed to keep system power constant with a minimum variation of accelerator power. A hollow cylinder-type metal fuel is designed for the on-line refueling concept. Lead-bismuth (Pb-Bi) is adopted as a coolant and spallation target material. 1 GeV 16 mA proton beam is designed to be provided for HYPER. HYPER is to transmute about 380 kg of TRU a year and produce 1000 MW of power. The support ratio of HYPER for LWR units producing the same power is believed to be 5∝6. (orig.)

  16. Cost-benefit analyses for the development of magma power

    International Nuclear Information System (INIS)

    Haraden, John

    1992-01-01

    Magma power is the potential generation of electricity from shallow magma bodies in the crust of the Earth. Considerable uncertainty still surrounds the development of magma power, but most of that uncertainty may be eliminated by drilling the first deep magma well. The uncertainty presents no serious impediments to the private drilling of the well. For reasons unrelated to the uncertainty, there may be no private drilling and there may be justification for public drilling. In this paper, we present cost-benefit analyses for private and public drilling of the well. Both analyses indicate there is incentive for drilling. (Author)

  17. Eutectic propeties of primitive Earth's magma ocean

    Science.gov (United States)

    Lo Nigro, G.; Andrault, D.; Bolfan-Casanova, N.; Perillat, J.-P.

    2009-04-01

    It is widely accepted that the early Earth was partially molten (if not completely) due to the high energy dissipated by terrestrial accretion [1]. After core formation, subsequent cooling of the magma ocean has led to fractional crystallization of the primitive mantle. The residual liquid corresponds to what is now called the fertile mantle or pyrolite. Melting relations of silicates have been extensively investigated using the multi-anvil press, for pressures between 3 and 25 GPa [2,3]. Using the quench technique, it has been shown that the pressure affects significantly the solidus and liquidus curves, and most probably the composition of the eutectic liquid. At higher pressures, up to 65 GPa, melting studies were performed on pyrolite starting material using the laser-heated diamond anvil cell (LH-DAC) technique [4]. However, the quench technique is not ideal to define melting criteria, and furthermore these studies were limited in pressure range of investigation. Finally, the use of pyrolite may not be relevant to study the melting eutectic temperature. At the core-mantle boundary conditions, melting temperature is documented by a single data point on (Mg,Fe)2SiO4 olivine, provided by shock wave experiments at around 130-140 GPa [5]. These previous results present large uncertainties of ~1000 K. The aim of this study is to determine the eutectic melting temperature in the chemically simplified system composed of the two major lower mantle phases, the MgSiO3 perovskite and MgO periclase. We investigated melting in-situ using the laser-heated diamond anvil cell coupled with angle dispersive X-ray diffraction at the ID27 beamline of the ESRF [6]. Melting relations were investigated in an extended P-T range comparable to those found in the Earth's lower mantle, i.e. from 25 to 120 GPa and up to more than 5000 K. Melting was evidenced from (a) disappearance of one of the two phases in the diffraction pattern, (b) drastic changes of the diffraction image itself, and

  18. Chemical consequences of compaction within the freezing front of a crystallizing magma ocean

    Science.gov (United States)

    Hier-Majumder, S.; Hirschmann, M. M.

    2013-12-01

    The thermal and compositional evolution of planetary magma oceans have profound influences on the early development and differentiation of terrestrial planets. During crystallization, rejection of elements incompatible in precipitating solids leads to petrologic and geochemical planetary differentiation, including potentially development of a compositionally stratified early mantle and evolution of thick overlying atmospheres. In cases of extremely efficient segregation of melt and crystals, solidified early mantles can be nearly devoid of key incompatible species including heat-producing (U, Th, K) and volatile (H,C,N,& noble gas) elements. A key structural component of a crystallizing magma ocean is the partially molten freezing front. The dynamics of this region influences the distribution of incompatible elements between the earliest mantle and the initial surficial reservoirs. It also can be the locus of heating owing to the dissipation of large amounts of tidal energy potentially available from the early Moon. The dynamics are influenced by the solidification rate, which is coupled to the liberation of volatiles owing to the modulating greenhouse effects in the overlying thick atmosphere. Compaction and melt retention in the freezing front of a magma ocean has received little previous attention. While the front advances during the course of crystallization, coupled conservation of mass, momentum, and energy within the front controls distribution and retention of melt within this layer. Due to compaction within this layer, melt distribution is far from uniform, and the fraction of melt trapped within this front depends on the rate of freezing of the magma ocean. During phases of rapid freezing, high amount of trapped melt within the freezing front retains a larger quantity of dissolved volatiles and the reverse is true during slow periods of crystallization. Similar effects are known from inferred trapped liquid fractions in layered mafic intrusions. Here we

  19. Outgassing From Open And Closed Magma Foams

    Science.gov (United States)

    von Aulock, Felix W.; Kennedy, Ben M.; Maksimenko, Anton; Wadsworth, Fabian B.; Lavallée, Yan

    2017-06-01

    During magma ascent, bubbles nucleate, grow, coalesce, and form a variably permeable porous network. The volcanic system opens and closes as bubble walls reorganize, seal or fail. In this contribution we cause obsidian to nucleate and grow bubbles to high gas volume fraction at atmospheric pressure by heating samples to 950 ºC for different times and we image the growth through a furnace. Following the experiment, we imaged the internal pore structure of selected samples in 3D and then dissected for analysis of textures and dissolved water content remnant in the glass. We demonstrate that in these high viscosity systems, during foaming and subsequent foam-maturation, bubbles near a free surface resorb via diffusion to produce an impermeable skin of melt around a foam. The skin thickens nonlinearly through time. The water concentrations at the outer and inner skin margins reflect the solubility of water in the melt at the partial pressure of water in atmospheric and water-rich bubble conditions, respectively. In this regime, mass transfer of water out of the system is diffusion limited and the sample shrinks slowly. In a second set of experiments in which we polished off the skin of the foamed samples and placed them back in the furnace, we observe rapid sample contraction and collapse of the connected pore network under surface tension as the system efficiently outgasses. In this regime, mass transfer of water is permeability limited. The mechanisms described here are relevant to the evolution of pore network heterogeneity in permeable magmas. We conclude that diffusion-driven skin formation can efficiently seal connectivity in foams. When rupture of melt film around gas bubbles (i.e. skin removal) occurs, then rapid outgassing and consequent foam collapse modulate gas pressurisation in the vesiculated magma.

  20. Experimental Constraints on a Vesta Magma Ocean

    Science.gov (United States)

    Hoff, C.; Jones, J. H.; Le, L.

    2014-01-01

    A magma ocean model was devised to relate eucrites (basalts) and diogenites (orthopyroxenites), which are found mixed together as clasts in a suite of polymict breccias known as howardites. The intimate association of eucritic and diogenitic clasts in howardites argues strongly that these three classes of achondritic meteorites all originated from the same planetoid. Reflectance spectral evidence (including that from the DAWN mission) has long suggested that Vesta is indeed the Eucrite Parent Body. Specifically, the magma ocean model was generated as follows: (i) the bulk Vesta composition was taken to be 0.3 CV chondrite + 0.7 L chondrite but using only 10% of the Na2O from this mixture; (ii) this composition is allowed to crystallize at 500 bar until approx. 80% of the system is solid olivine + low-Ca pyroxene; (iii) the remaining 20% liquid crystallizes at one bar from 1250C to 1110C, a temperature slightly above the eucrite solidus. All crystallization calculations were performed using MELTS. In this model, diogenites are produced by cocrystallization of olivine and pyroxene in the >1250C temperature regime, with Main Group eucrite liquids being generated in the 1300-1250C temperature interval. Low-Ca pyroxene reappears at 1210C in the one-bar calculations and fractionates the residual liquid to produce evolved eucrite compositions (Stannern Trend). We have attempted to experimentally reproduce the magma ocean. In the MELTS calculation, the change from 500 bar to one bar results in a shift of the olivine:low-Ca pyroxene boundary so that the 1250C liquid is now in the olivine field and, consequently, olivine should be the first-crystallizing phase, followed by low-Ca pyroxene at 1210C, and plagioclase at 1170C. Because at one bar the olivine:low-Ca pyroxene boundary is a peritectic, fractional crystallization of the 1210C liquid proceeds with only pyroxene crystallization until plagioclase appears. Thus, the predictions of the MELTS calculation are clear and

  1. Outgassing from Open and Closed Magma Foams

    Directory of Open Access Journals (Sweden)

    Felix W. von Aulock

    2017-06-01

    Full Text Available During magma ascent, bubbles nucleate, grow, coalesce, and form a variably permeable porous network. The reorganization, failing and sealing of bubble walls may contribute to the opening and closing of the volcanic system. In this contribution we cause obsidian to nucleate and grow bubbles to high gas volume fraction at atmospheric pressure by heating samples to 950°C for different times and we image the growth through a furnace. Following the experiment, we imaged the internal pore structure of selected samples in 3D and then dissected for analysis of textures and dissolved water content remnant in the glass. We demonstrate that in these high viscosity systems, during foaming and subsequent foam-maturation, bubbles near a free surface resorb via diffusion to produce an impermeable skin of melt around a foam. The skin thickens non-linearly through time. The water concentrations at the outer and inner skin margins reflect the solubility of water in the melt at the partial pressure of water in atmospheric and water-rich bubble conditions, respectively. In this regime, mass transfer of water out of the system is diffusion limited and the sample shrinks slowly. In a second set of experiments in which we polished off the skin of the foamed samples and placed them back in the furnace to allow open system outgassing, we observe rapid sample contraction and collapse of the connected pore network under surface tension as the system efficiently outgasses. In this regime, mass transfer of water is permeability limited. We conclude that diffusion-driven skin formation can efficiently seal connectivity in foams. When rupture of melt film around gas bubbles (i.e., skin removal occurs, then rapid outgassing and consequent foam collapse modulate gas pressurization in the vesiculated magma. The mechanisms described here are relevant to the evolution of pore network heterogeneity in permeable magmas.

  2. Experimental Study of Lunar and SNC Magmas

    Science.gov (United States)

    Rutherford, Malcolm J.

    1998-01-01

    The research described in this progress report involved the study of petrological, geochemical and volcanic processes that occur on the Moon and the SNC parent body, generally accepted to be Mars. The link between these studies is that they focus on two terrestrial-type parent bodies somewhat smaller than earth, and the fact that they focus on the role of volatiles in magmatic processes and on processes of magma evolution on these planets. The work on the lunar volcanic glasses has resulted in some exciting new discoveries over the years of this grant. We discovered small metal blebs initially in the Al5 green glass, and determined the significant importance of this metal in fixing the oxidation state of the parent magma (Fogel and Rutherford, 1995). More recently, we discovered a variety of metal blebs in the Al7 orange glass. Some of these Fe-Ni metal blebs were in the glass; others were in olivine phenocrysts. The importance of these metal spheres is that they fix the oxidation state of the parent magma during the eruption, and also indicate changes during the eruption (Weitz et al., 1997) They also yield important information about the composition of the gas phase present, the gas which drove the lunar fire-fountaining. One of the more exciting and controversial findings in our research over the past year has been the possible fractionation of H from D during shock (experimental) of hornblende bearing samples (Minitti et al., 1997). This research is directed at explaining some of the low H2O and high D/H observed in hydrous phases in the SNC meteorites.

  3. Special relativity derived from spacetime magma.

    Science.gov (United States)

    Greensite, Fred

    2014-01-01

    We present a derivation of relativistic spacetime largely untethered from specific physical considerations, in constrast to the many physically-based derivations that have appeared in the last few decades. The argument proceeds from the inherent magma (groupoid) existing on the union of spacetime frame components [Formula: see text] and Euclidean [Formula: see text] which is consistent with an "inversion symmetry" constraint from which the Minkowski norm results. In this context, the latter is also characterized as one member of a class of "inverse norms" which play major roles with respect to various unital [Formula: see text]-algebras more generally.

  4. Special relativity derived from spacetime magma.

    Directory of Open Access Journals (Sweden)

    Fred Greensite

    Full Text Available We present a derivation of relativistic spacetime largely untethered from specific physical considerations, in constrast to the many physically-based derivations that have appeared in the last few decades. The argument proceeds from the inherent magma (groupoid existing on the union of spacetime frame components [Formula: see text] and Euclidean [Formula: see text] which is consistent with an "inversion symmetry" constraint from which the Minkowski norm results. In this context, the latter is also characterized as one member of a class of "inverse norms" which play major roles with respect to various unital [Formula: see text]-algebras more generally.

  5. Dynamics of differentiation in magma reservoirs

    Science.gov (United States)

    Jaupart, Claude; Tait, Stephen

    1995-09-01

    In large magma chambers, gradients of temperature and composition develop due to cooling and to fractional crystallization. Unstable density differences lead to differential motions between melt and crystals, and a major goal is to explain how this might result in chemical differentiation of magma. Arriving at a full description of the physics of crystallizing magma chambers is a challenge because of the large number of processes potentially involved, the many coupled variables, and the different geometrical shapes. Furthermore, perturbations are caused by the reinjection of melt from a deep source, eruption to the Earth's surface, and the assimilation of country rock. Physical models of increasing complexity have been developed with emphasis on three fundamental approaches. One is, given that large gradients in temperature and composition may occur, to specify how to apply thermodynamic constraints so that coexisting liquid and solid compositions may be calculated. The second is to leave the differentiation trend as the solution to be found, i.e., to specify how cooling occurs and to predict the evolution of the composition of the residual liquid and of the solid forming. The third is to simplify the physics so that the effects of coupled heat and mass transfer may be studied with a reduced set of variables. The complex shapes of magma chambers imply that boundary layers develop with density gradients at various angles to gravity, leading to various convective flows and profiles qf liquid stratification. Early studies were mainly concerned with describing fluid flow in the liquid interior of large reservoirs, due to gradients developed at the margins. More recent work has focused on the internal structure and flow field of boundary layers and in particular on the gradients of solid fraction and interstitial melt composition which develop within them. Crystal settling may occur in a surprisingly diverse range of regimes and may lead to intermittent deposition

  6. Magma evolution inside the 1631 Vesuvius magma chamber and eruption triggering

    Science.gov (United States)

    Stoppa, Francesco; Principe, Claudia; Schiazza, Mariangela; Liu, Yu; Giosa, Paola; Crocetti, Sergio

    2017-03-01

    Vesuvius is a high-risk volcano and the 1631 Plinian eruption is a reference event for the next episode of explosive unrest. A complete stratigraphic and petrographic description of 1631 pyroclastics is given in this study. During the 1631 eruption a phonolite was firstly erupted followed by a tephritic phonolite and finally a phonolitic tephrite, indicating a layered magma chamber. We suggest that phonolitic basanite is a good candidate to be the primitive parental-melt of the 1631 eruption. Composition of apatite from the 1631 pyroclastics is different from those of CO2-rich melts indicating negligible CO2 content during magma evolution. Cross checking calculations, using PETROGRAPH and PELE software, accounts for multistage evolution up to phonolite starting from a phonolitic basanite melt similar to the Vesuvius medieval lavas. The model implies crystal settling of clinopyroxene and olivine at 6 kbar and 1220°C, clinopyroxene plus leucite at a pressure ranging from 2.5 to 0.5 kbar and temperature ranging from 1140 to 940°C. Inside the phonolitic magma chamber K-feldspar and leucite would coexist at a temperature ranging from from 940 to 840°C and at a pressure ranging from 2.5 to0.5 kbar. Thus crystal fractionation is certainly a necessary and probably a sufficient condition to evolve the melt from phono tephritic to phonolitic in the 1631 magma chamber. We speculate that phonolitic tephrite magma refilling from deeper levels destabilised the chamber and triggered the eruption, as testified by the seismic precursor phenomena before 1631 unrest.

  7. Magma evolution inside the 1631 Vesuvius magma chamber and eruption triggering

    Directory of Open Access Journals (Sweden)

    Stoppa Francesco

    2017-03-01

    Full Text Available Vesuvius is a high-risk volcano and the 1631 Plinian eruption is a reference event for the next episode of explosive unrest. A complete stratigraphic and petrographic description of 1631 pyroclastics is given in this study. During the 1631 eruption a phonolite was firstly erupted followed by a tephritic phonolite and finally a phonolitic tephrite, indicating a layered magma chamber. We suggest that phonolitic basanite is a good candidate to be the primitive parental-melt of the 1631 eruption. Composition of apatite from the 1631 pyroclastics is different from those of CO2-rich melts indicating negligible CO2 content during magma evolution. Cross checking calculations, using PETROGRAPH and PELE software, accounts for multistage evolution up to phonolite starting from a phonolitic basanite melt similar to the Vesuvius medieval lavas. The model implies crystal settling of clinopyroxene and olivine at 6 kbar and 1220°C, clinopyroxene plus leucite at a pressure ranging from 2.5 to 0.5 kbar and temperature ranging from 1140 to 940°C. Inside the phonolitic magma chamber K-feldspar and leucite would coexist at a temperature ranging from from 940 to 840°C and at a pressure ranging from 2.5 to0.5 kbar. Thus crystal fractionation is certainly a necessary and probably a sufficient condition to evolve the melt from phono tephritic to phonolitic in the 1631 magma chamber. We speculate that phonolitic tephrite magma refilling from deeper levels destabilised the chamber and triggered the eruption, as testified by the seismic precursor phenomena before 1631 unrest.

  8. Efficient energy extraction from a diode-pumped Q-switched Tm,Ho:YLiF4 laser

    Science.gov (United States)

    Mcguckin, B. T.; Menzies, R. T.; Hemmati, H.

    1991-01-01

    The operation of a diode-laser pumped thulium, holmium yttrium-lithium-fluoride laser (Tm,Ho:YLF) in Q-switched mode is reported. Output energies of 200 microjoules in pulses of 22 ns duration are recorded at Q-switch frequencies commensurate with an effective upper laser level lifetime of 6 ms. This lifetime is appreciably longer than that observed in other hosts permitting stored energy extraction of 64 percent, close to the projected maximum performance from these materials.

  9. Steady-state analysis of a conceptual offshore wind turbine driven electricity and thermocline energy extraction plant

    OpenAIRE

    Buhagiar, Daniel; Sant, Tonio

    2014-01-01

    A system for using offshore wind energy to generate electricity and simultaneously extract thermal energy is proposed. This concept is based on an offshore wind turbine driven hydraulic pump supplying deep seawater under high pressure to a land based plant consisting of a hydroelectric power generation unit and heat exchanger. A steady-state system model is developed using empirical formulae. The mathematical model comprises the fundamental system sub-models that are categoris...

  10. Geothermal heat from solid rock - increased energy extraction through hydraulic pressurizing of drill wells

    International Nuclear Information System (INIS)

    Ramstad, Randi Kalskin; Hilmo, Bernt Olav; Skarphagen, Helge

    2005-01-01

    more suited in this study than continued measurements for documenting the alterations in the drill hole capacities and current patterns. Drill hole inspection give valuable information about cracking conditions, possible water conducting faults, ground water quality, water temperature and currents but changes in the drill hole walls as a consequence of hydraulic pressurizing is difficult to determine. The efficacy test of the ground water plant at Bryn did show that the infiltration capacity at the central drill hole is too low compared to the stipulated project conditions but the plant at EAB may be operated as planned. Compared to more conventional ground water plants with collectors the plant at EAB would be profitable. At the present economic and geologic conditions the plant costs may be reduced with more than 50 % by choosing a plant based on pumping up ground water at the EAB where the energy extraction from water is higher than 105 MWh/year. A yearly energy consumption of 195 MWh is based on a current velocity of 14 m3/hour, an average temperature extraction of 2.1 deg C and 3000 operation hours. The profitability would be improved further if the plant would be used both for heating and cooling purposes. The ground water quality at all the test sites was satisfactory

  11. Intrusion of basaltic magma into a crystallizing granitic magma chamber: The Cordillera del Paine pluton in southern Chile

    Science.gov (United States)

    Michael, Peter J.

    1991-10-01

    The Cordillera del Paine pluton in the southernmost Andes of Chile represents a deeply dissected magma chamber where mafic magma intruded into crystallizing granitic magma. Throughout much of the 10x15 km pluton, there is a sharp and continuous boundary at a remarkably constant elevation of 1,100 m that separates granitic rocks (Cordillera del Paine or CP granite: 69 77% SiO2) which make up the upper levels of the pluton from mafic and comingled rocks (Paine Mafic Complex or PMC: 45 60% SiO2) which dominate the lower exposures of the pluton. Chilled, crenulate, disrupted contacts of mafic rock against granite demonstrate that partly crystallized granite was intruded by mafic magma which solidified prior to complete crystallization of the granitic magma. The boundary at 1,100 m was a large and stable density contrast between the denser, hotter mafic magma and cooler granitic magma. The granitic magma was more solidified near the margins of the chamber when mafic intrusion occurred, and the PMC is less disrupted by granites there. Near the pluton margins, the PMC grades upward irregularly from cumulate gabbros to monzodiorites. Mafic magma differentiated largely by fractional crystallization as indicated by the presence of cumulate rocks and by the low levels of compatible elements in most PMC rocks. The compositional gap between the PMC and CP granite indicates that mixing (blending) of granitic magma into the mafic magma was less important, although it is apparent from mineral assemblages in mafic rocks. Granitic magma may have incorporated small amounts of mafic liquid that had evolved to >60% SiO2 by crystallization. Mixing was inhibited by the extent of crystallization of the granite, and by the thermal contrast and the stable density contrast between the magmas. PMC gabbros display disequilibrium mineral assemblages including early formed zoned olivine (with orthopyroxene coronas), clinopyroxene, calcic plagioclase and paragasite and later-formed amphibole

  12. Life cycle analysis on fossil energy ratio of algal biodiesel: effects of nitrogen deficiency and oil extraction technology.

    Science.gov (United States)

    Jian, Hou; Jing, Yang; Peidong, Zhang

    2015-01-01

    Life cycle assessment (LCA) has been widely used to analyze various pathways of biofuel preparation from "cradle to grave." Effects of nitrogen supply for algae cultivation and technology of algal oil extraction on life cycle fossil energy ratio of biodiesel are assessed in this study. Life cycle fossil energy ratio of Chlorella vulgaris based biodiesel is improved by growing algae under nitrogen-limited conditions, while the life cycle fossil energy ratio of biodiesel production from Phaeodactylum tricornutum grown with nitrogen deprivation decreases. Compared to extraction of oil from dried algae, extraction of lipid from wet algae with subcritical cosolvents achieves a 43.83% improvement in fossil energy ratio of algal biodiesel when oilcake drying is not considered. The outcome for sensitivity analysis indicates that the algal oil conversion rate and energy content of algae are found to have the greatest effects on the LCA results of algal biodiesel production, followed by utilization ratio of algal residue, energy demand for algae drying, capacity of water mixing, and productivity of algae.

  13. Quality Assessment of Roof Planes Extracted from Height Data for Solar Energy Systems by the EAGLE Platform

    Directory of Open Access Journals (Sweden)

    Simon Schuffert

    2015-12-01

    Full Text Available Due to the increasing scarcity of fossil fuels and the upwards trend in energy costs over time, many countries—especially in Europe—have begun to modify their energy policies aiming to increase that percentage obtained from renewable energies. The EAGLE (FP7 program, European Commission has developed a web-based platform to promote renewable energy systems (RES in the public and private sectors, and to deliver a comprehensive information source for all interested users. In this paper, a comprehensive quality assessment of extracted roof planes suitable for solar energy installations (photovoltaic, solar thermal from height data derived automatically from both LiDAR (Light Detection and Ranging and aerial images will be presented. A shadow analysis is performed regarding the daily path of the sun including the shading effects of nearby objects (chimneys, dormers, vegetation, buildings, topography, etc.. A quality assessment was carried out for both LiDAR and aerial images of the same test sites in UK and Germany concerning building outline accuracy, extraction rate of roof planes and the accuracy of their geometric parameters (inclination and aspect angle, size. The benefit is an optimized system to extract roof planes for RES with a high level of detail, accuracy and flexibility (concerning different commonly available data sources including an estimation of quality of the results which is important for individual house owners as well as for regional applications by governments or solar energy companies to judge their usefulness.

  14. Discovering Mathematics with Magma Reducing the Abstract to the Concrete

    CERN Document Server

    Bosma, Wieb

    2006-01-01

    With a design based on the ontology and semantics of algebra, Magma enables users to rapidly formulate and perform calculations in the more abstract parts of mathematics. This book introduces the role Magma plays in advanced mathematical research through 14 case studies which, in most cases, describe computations underpinning theoretical results.

  15. Zircons reveal magma fluxes in the Earth's crust.

    Science.gov (United States)

    Caricchi, Luca; Simpson, Guy; Schaltegger, Urs

    2014-07-24

    Magma fluxes regulate the planetary thermal budget, the growth of continents and the frequency and magnitude of volcanic eruptions, and play a part in the genesis and size of magmatic ore deposits. However, because a large fraction of the magma produced on the Earth does not erupt at the surface, determinations of magma fluxes are rare and this compromises our ability to establish a link between global heat transfer and large-scale geological processes. Here we show that age distributions of zircons, a mineral often present in crustal magmatic rocks, in combination with thermal modelling, provide an accurate means of retrieving magma fluxes. The characteristics of zircon age populations vary significantly and systematically as a function of the flux and total volume of magma accumulated in the Earth's crust. Our approach produces results that are consistent with independent determinations of magma fluxes and volumes of magmatic systems. Analysis of existing age population data sets using our method suggests that porphyry-type deposits, plutons and large eruptions each require magma input over different timescales at different characteristic average fluxes. We anticipate that more extensive and complete magma flux data sets will serve to clarify the control that the global heat flux exerts on the frequency of geological events such as volcanic eruptions, and to determine the main factors controlling the distribution of resources on our planet.

  16. Geothermal energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role of geothermal energy may have on the energy future of the US. The topics discussed in the chapter include historical aspects of geothermal energy, the geothermal resource, hydrothermal fluids, electricity production, district heating, process heating, geopressured brines, technology and costs, hot dry rock, magma, and environmental and siting issues

  17. U-series isotopes in arc magma

    Energy Technology Data Exchange (ETDEWEB)

    Hawkesworth, C.; Turner, S.; McDermott, F.; Peate, D.; Van Calsteren, P.

    1997-12-31

    Thorium is not readily mobilized in the fluid component along destructive plate margins. Uranium is mobilized, and the resultant fractionation in U/Th can be used to estimate the rates of transfer slab derived components through the mantle wedge. The variations in Th/Yb, and by implication in the fractionation-corrected Th abundances of arc magmas largely depend on the contributions from subducted sediments. It is inferred that the distinctive high Th/Ta ratios of subduction related magmas primarily reflect the Th/Ta ratios of the subducted sediments, and that such high Th/Ta ratios are generated by processes other than those associated with recent subduction-related magmatism. Uranium and thorium isotopes have also been used to evaluate magma residence times within the crust. Thus, separated minerals and groundmass from six rocks erupted in the last 4,000 years from Soufriere on St. Vincent in the Lesser Antilles, scatter about a 50,000 year errorchron on the U-Th equiline diagram (Heath et al., 1977). Models are currently being developed to investigate how such apparent ages may relate to calculated replenishment times in steady state systems. Bulk continental crust has a lower U/Th ratio (0.25) than at least some estimates for the bulk Earth (0.26) and the depleted upper mantle (0.39). However, the island arc rocks with low U/Th ratios appear to have inherited those from subducted sediments, and arc rocks with a low sediment contribution have significantly higher U/Th. Consequently, the U/Th ratios of new crustal material generated along destructive plate margins are significantly higher than those of bulk continental crust. The low average U/Th of bulk crust may be primarily due to different crust generation processes in the Archaean, when U would be less mobile because conditions were less oxidising, and when residual garnet may have had more of a role in crust generation processes. Extended abstract. 4 figs., 23 refs.

  18. Hydrogen isotopic fractionation during crystallization of the terrestrial magma ocean

    Science.gov (United States)

    Pahlevan, K.; Karato, S. I.

    2016-12-01

    Models of the Moon-forming giant impact extensively melt and partially vaporize the silicate Earth and deliver a substantial mass of metal to the Earth's core. The subsequent evolution of the terrestrial magma ocean and overlying vapor atmosphere over the ensuing 105-6 years has been largely constrained by theoretical models with remnant signatures from this epoch proving somewhat elusive. We have calculated equilibrium hydrogen isotopic fractionation between the magma ocean and overlying steam atmosphere to determine the extent to which H isotopes trace the evolution during this epoch. By analogy with the modern silicate Earth, the magma ocean-steam atmosphere system is often assumed to be chemically oxidized (log fO2 QFM) with the dominant atmospheric vapor species taken to be water vapor. However, the terrestrial magma ocean - having held metallic droplets in suspension - may also exhibit a much more reducing character (log fO2 IW) such that equilibration with the overlying atmosphere renders molecular hydrogen the dominant H-bearing vapor species. This variable - the redox state of the magma ocean - has not been explicitly included in prior models of the coupled evolution of the magma ocean-steam atmosphere system. We find that the redox state of the magma ocean influences not only the vapor speciation and liquid-vapor partitioning of hydrogen but also the equilibrium isotopic fractionation during the crystallization epoch. The liquid-vapor isotopic fractionation of H is substantial under reducing conditions and can generate measurable D/H signatures in the crystallization products but is largely muted in an oxidizing magma ocean and steam atmosphere. We couple equilibrium isotopic fractionation with magma ocean crystallization calculations to forward model the behavior of hydrogen isotopes during this epoch and find that the distribution of H isotopes in the silicate Earth immediately following crystallization represents an oxybarometer for the terrestrial

  19. Magma heating by decompression-driven crystallization beneath andesite volcanoes.

    Science.gov (United States)

    Blundy, Jon; Cashman, Kathy; Humphreys, Madeleine

    2006-09-07

    Explosive volcanic eruptions are driven by exsolution of H2O-rich vapour from silicic magma. Eruption dynamics involve a complex interplay between nucleation and growth of vapour bubbles and crystallization, generating highly nonlinear variation in the physical properties of magma as it ascends beneath a volcano. This makes explosive volcanism difficult to model and, ultimately, to predict. A key unknown is the temperature variation in magma rising through the sub-volcanic system, as it loses gas and crystallizes en route. Thermodynamic modelling of magma that degasses, but does not crystallize, indicates that both cooling and heating are possible. Hitherto it has not been possible to evaluate such alternatives because of the difficulty of tracking temperature variations in moving magma several kilometres below the surface. Here we extend recent work on glassy melt inclusions trapped in plagioclase crystals to develop a method for tracking pressure-temperature-crystallinity paths in magma beneath two active andesite volcanoes. We use dissolved H2O in melt inclusions to constrain the pressure of H2O at the time an inclusion became sealed, incompatible trace element concentrations to calculate the corresponding magma crystallinity and plagioclase-melt geothermometry to determine the temperature. These data are allied to ilmenite-magnetite geothermometry to show that the temperature of ascending magma increases by up to 100 degrees C, owing to the release of latent heat of crystallization. This heating can account for several common textural features of andesitic magmas, which might otherwise be erroneously attributed to pre-eruptive magma mixing.

  20. Longevity of magma in the near subsurface

    International Nuclear Information System (INIS)

    Marsh, B.D.; Resmini, R.G.

    1992-01-01

    Small, sporadic occurrences of basaltic volcanism are particularly difficult to evaluate in terms of long term threat to mankind because of their short overall eruptive history. Insight into future eruptive vigor and possible subsurface magma storage may be furnished by studying the ages of crystals in the eruptive products themselves. In this paper, the authors do this by applying the method of crystal size distribution theory (CSD) to a stack of basaltic lavas within the Nevada test site; namely the Dome Mtn. lavas. Preliminary results suggest a pre-eruptive residence time of 10 - 20 years, decreasing with decreasing age of lava within the sequence. These times are similar to those found by M.T. Mangan for the 1959 Kilauea (Hawaii) eruptions, and may suggest a relatively vigorous magmatic system at this time some 8 m.y. ago. Work is progressing on a greatly expanded CSD analysis of the Dome Mtn. lavas

  1. The role of water in unconventional in situ energy resource extraction technologies: Chapter 7 in Food, energy, and water: The chemistry connection

    Science.gov (United States)

    Gallegos, Tanya J.; Bern, Carleton R.; Birdwell, Justin E.; Haines, Seth; Engle, Mark A.

    2015-01-01

    Global trends toward developing new energy resources from lower grade, larger tonnage deposits that are not generally accessible using “conventional” extraction methods involve variations of subsurface in situ extraction techniques including in situ oil-shale retorting, hydraulic fracturing of petroleum reservoirs, and in situ recovery (ISR) of uranium. Although these methods are economically feasible and perhaps result in a smaller above-ground land-use footprint, there remain uncertainties regarding potential subsurface impacts to groundwater. This chapter provides an overview of the role of water in these technologies and the opportunities and challenges for water reuse and recycling.

  2. Permeability During Magma Expansion and Compaction

    Science.gov (United States)

    Gonnermann, Helge. M.; Giachetti, Thomas; Fliedner, Céline; Nguyen, Chinh T.; Houghton, Bruce F.; Crozier, Joshua A.; Carey, Rebecca J.

    2017-12-01

    Plinian lapilli from the 1060 Common Era Glass Mountain rhyolitic eruption of Medicine Lake Volcano, California, were collected and analyzed for vesicularity and permeability. A subset of the samples were deformed at a temperature of 975°, under shear and normal stress, and postdeformation porosities and permeabilities were measured. Almost all undeformed samples fall within a narrow range of vesicularity (0.7-0.9), encompassing permeabilities between approximately 10-15 m2 and 10-10 m2. A percolation threshold of approximately 0.7 is required to fit the data by a power law, whereas a percolation threshold of approximately 0.5 is estimated by fitting connected and total vesicularity using percolation modeling. The Glass Mountain samples completely overlap with a range of explosively erupted silicic samples, and it remains unclear whether the erupting magmas became permeable at porosities of approximately 0.7 or at lower values. Sample deformation resulted in compaction and vesicle connectivity either increased or decreased. At small strains permeability of some samples increased, but at higher strains permeability decreased. Samples remain permeable down to vesicularities of less than 0.2, consistent with a potential hysteresis in permeability-porosity between expansion (vesiculation) and compaction (outgassing). We attribute this to retention of vesicle interconnectivity, albeit at reduced vesicle size, as well as bubble coalescence during shear deformation. We provide an equation that approximates the change in permeability during compaction. Based on a comparison with data from effusively erupted silicic samples, we propose that this equation can be used to model the change in permeability during compaction of effusively erupting magmas.

  3. Variations in magma supply rate at Kilauea Volcano, Hawaii

    Science.gov (United States)

    Dvorak, John J.; Dzurisin, Daniel

    1993-01-01

    When an eruption of Kilauea lasts more than 4 months, so that a well-defined conduit has time to develop, magma moves freely through the volcano from a deep source to the eruptive site at a constant rate of 0.09 km3/yr. At other times, the magma supply rate to Kilauea, estimated from geodetic measurements of surface displacements, may be different. For example, after a large withdrawal of magma from the summit reservoir, such as during a rift zone eruption, the magma supply rate is high initially but then lessens and exponentially decays as the reservoir refills. Different episodes of refilling may have different average rates of magma supply. During four year-long episodes in the 1960s, the annual rate of refilling varied from 0.02 to 0.18 km3/yr, bracketing the sustained eruptive rate of 0.09 km3/yr. For decade-long or longer periods, our estimate of magma supply rate is based on long-term changes in eruptive rate. We use eruptive rate because after a few dozen eruptions the volume of magma that passes through the summit reservoir is much larger than the net change of volume of magma stored within Kilauea. The low eruptive rate of 0.009 km3/yr between 1840 and 1950, compared to an average eruptive rate of 0.05 km3/yr since 1950, suggests that the magma supply rate was lower between 1840 and 1950 than it has been since 1950. An obvious difference in activity before and since 1950 was the frequency of rift zone eruptions: eight rift zone eruptions occurred between 1840 and 1950, but more than 20 rift zone eruptions have occurred since 1950. The frequency of rift zone eruptions influences magma supply rate by suddenly lowering pressure of the summit magma reservoir, which feeds magma to rift zone eruptions. A temporary drop of reservoir pressure means a larger-than-normal pressure difference between the reservoir and a deeper source, so magma is forced to move upward into Kilauea at a faster rate.

  4. The applications of microwave energy to improve grindability and extraction of gold ores

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.H

    2000-10-01

    In this study, the applications of microwave energy in gold ore processing were investigated. An investigation of microwave heating characteristics indicated that the heating rate of an ore was not only related to the applied microwave field, but also to the mineralogy of the ore. Heating rate and the difference between the bulk temperature of an ore and the local temperature of high dielectric loss minerals increased with applied microwave power level, the content of high dielectric loss minerals, the particle size of the ore and the disseminated high dielectric loss minerals. The relationship between heating rate and surrounding environment is also discussed in this study. Investigations indicated that the microwave exposure could reduce the grindability of ores. For the Lihir gold ore, a decrease of 11% in the comparative grindability was obtained when it was exposed to 1500W microwave energy for 8 minutes. The decrease in grinding resistance resulted predominantly from the fractures induced by thermal stresses and differential thermal expansion of mineral phases during microwave heating. Experimental results showed that marcasite and pyrite could be decomposed into elemental sulphur and pyrrhotite-like Fe-S phases in an inert atmosphere, or oxidised into a porous hematite (Fe{sub 2}O{sub 3}) in an air atmosphere when they were exposed to microwaves. Microwave power had a significant impact on the decomposition of pyrite and marcasite. Marcasite was more readily decomposed than pyrite at the same exposure conditions. Scanning electron microscope (SEM), optical microscope, and X-ray diffraction results indicated that the alterations during microwave treatment were complex. Some intermediate products (e.g. Fe{sub (1-x)}S) were formed before the sulphides were completely oxidised into hematite (Fe{sub 2}O{sub 3}). Oxidation developed from the surfaces into the cores of the microwaved particles. Metallic particles were also formed during microwave exposure. Lihir

  5. The applications of microwave energy to improve grindability and extraction of gold ores

    International Nuclear Information System (INIS)

    Huang, J.H.

    2000-10-01

    In this study, the applications of microwave energy in gold ore processing were investigated. An investigation of microwave heating characteristics indicated that the heating rate of an ore was not only related to the applied microwave field, but also to the mineralogy of the ore. Heating rate and the difference between the bulk temperature of an ore and the local temperature of high dielectric loss minerals increased with applied microwave power level, the content of high dielectric loss minerals, the particle size of the ore and the disseminated high dielectric loss minerals. The relationship between heating rate and surrounding environment is also discussed in this study. Investigations indicated that the microwave exposure could reduce the grindability of ores. For the Lihir gold ore, a decrease of 11% in the comparative grindability was obtained when it was exposed to 1500W microwave energy for 8 minutes. The decrease in grinding resistance resulted predominantly from the fractures induced by thermal stresses and differential thermal expansion of mineral phases during microwave heating. Experimental results showed that marcasite and pyrite could be decomposed into elemental sulphur and pyrrhotite-like Fe-S phases in an inert atmosphere, or oxidised into a porous hematite (Fe 2 O 3 ) in an air atmosphere when they were exposed to microwaves. Microwave power had a significant impact on the decomposition of pyrite and marcasite. Marcasite was more readily decomposed than pyrite at the same exposure conditions. Scanning electron microscope (SEM), optical microscope, and X-ray diffraction results indicated that the alterations during microwave treatment were complex. Some intermediate products (e.g. Fe (1-x) S) were formed before the sulphides were completely oxidised into hematite (Fe 2 O 3 ). Oxidation developed from the surfaces into the cores of the microwaved particles. Metallic particles were also formed during microwave exposure. Lihir gold ore, in which

  6. Photo-generated carriers lose energy during extraction from polymer-fullerene solar cells

    KAUST Repository

    Melianas, Armantas; Etzold, Fabian; Savenije, Tom J.; Laquai, Fré dé ric; Inganä s, Olle; Kemerink, Martijn

    2015-01-01

    motion is boosted by this process, leading to a time-dependent carrier mobility as confirmed by direct experiments. We identify the time and distance scales relevant for carrier extraction and show that the photo-generated carriers are extracted from

  7. The effects of logging residue extraction for energy on ecosystem services and biodiversity: A synthesis.

    Science.gov (United States)

    Ranius, Thomas; Hämäläinen, Aino; Egnell, Gustaf; Olsson, Bengt; Eklöf, Karin; Stendahl, Johan; Rudolphi, Jörgen; Sténs, Anna; Felton, Adam

    2018-03-01

    We review the consequences for biodiversity and ecosystem services from the industrial-scale extraction of logging residues (tops, branches and stumps from harvested trees and small-diameter trees from thinnings) in managed forests. Logging residue extraction can replace fossil fuels, and thus contribute to climate change mitigation. The additional biomass and nutrients removed, and soils and other structures disturbed, have several potential environmental impacts. To evaluate potential impacts on ecosystem services and biodiversity we reviewed 279 scientific papers that compared logging residue extraction with non-extraction, the majority of which were conducted in Northern Europe and North America. The weight of available evidence indicates that logging residue extraction can have significant negative effects on biodiversity, especially for species naturally adapted to sun-exposed conditions and the large amounts of dead wood that are created by large-scaled forest disturbances. Slash extraction may also pose risks for future biomass production itself, due to the associated loss of nutrients. For water quality, reindeer herding, mammalian game species, berries, and natural heritage the results were complicated by primarily negative but some positive effects, while for recreation and pest control positive effects were more consistent. Further, there are initial negative effects on carbon storage, but these effects are transient and carbon stocks are mostly restored over decadal time perspectives. We summarize ways of decreasing some of the negative effects of logging residue extraction on specific ecosystem services, by changing the categories of residue extracted, and site or forest type targeted for extraction. However, we found that suggested pathways for minimizing adverse outcomes were often in conflict among the ecosystem services assessed. Compensatory measures for logging residue extraction may also be used (e.g. ash recycling, liming, fertilization

  8. MAGMA: analysis of two-channel microarrays made easy.

    Science.gov (United States)

    Rehrauer, Hubert; Zoller, Stefan; Schlapbach, Ralph

    2007-07-01

    The web application MAGMA provides a simple and intuitive interface to identify differentially expressed genes from two-channel microarray data. While the underlying algorithms are not superior to those of similar web applications, MAGMA is particularly user friendly and can be used without prior training. The user interface guides the novice user through the most typical microarray analysis workflow consisting of data upload, annotation, normalization and statistical analysis. It automatically generates R-scripts that document MAGMA's entire data processing steps, thereby allowing the user to regenerate all results in his local R installation. The implementation of MAGMA follows the model-view-controller design pattern that strictly separates the R-based statistical data processing, the web-representation and the application logic. This modular design makes the application flexible and easily extendible by experts in one of the fields: statistical microarray analysis, web design or software development. State-of-the-art Java Server Faces technology was used to generate the web interface and to perform user input processing. MAGMA's object-oriented modular framework makes it easily extendible and applicable to other fields and demonstrates that modern Java technology is also suitable for rather small and concise academic projects. MAGMA is freely available at www.magma-fgcz.uzh.ch.

  9. Forecasting magma-chamber rupture at Santorini volcano, Greece.

    Science.gov (United States)

    Browning, John; Drymoni, Kyriaki; Gudmundsson, Agust

    2015-10-28

    How much magma needs to be added to a shallow magma chamber to cause rupture, dyke injection, and a potential eruption? Models that yield reliable answers to this question are needed in order to facilitate eruption forecasting. Development of a long-lived shallow magma chamber requires periodic influx of magmas from a parental body at depth. This redistribution process does not necessarily cause an eruption but produces a net volume change that can be measured geodetically by inversion techniques. Using continuum-mechanics and fracture-mechanics principles, we calculate the amount of magma contained at shallow depth beneath Santorini volcano, Greece. We demonstrate through structural analysis of dykes exposed within the Santorini caldera, previously published data on the volume of recent eruptions, and geodetic measurements of the 2011-2012 unrest period, that the measured 0.02% increase in volume of Santorini's shallow magma chamber was associated with magmatic excess pressure increase of around 1.1 MPa. This excess pressure was high enough to bring the chamber roof close to rupture and dyke injection. For volcanoes with known typical extrusion and intrusion (dyke) volumes, the new methodology presented here makes it possible to forecast the conditions for magma-chamber failure and dyke injection at any geodetically well-monitored volcano.

  10. Formation of thick stratiform Fe-Ti oxide layers in layered intrusion and frequent replenishment of fractionated mafic magma: Evidence from the Panzhihua intrusion, SW China

    Science.gov (United States)

    Song, Xie-Yan; Qi, Hua-Wen; Hu, Rui-Zhong; Chen, Lie-Meng; Yu, Song-Yue; Zhang, Jia-Fei

    2013-03-01

    Panzhihua intrusion is one of the largest layered intrusions that hosts huge stratiform Fe-Ti oxide layers in the central part of the Emeishan large igneous province, SW China. Up to 60 m thick stratiform massive Fe-Ti oxide layers containing 85 modal% of magnetite and ilmenite and overlying magnetite gabbro compose cyclic units of the Lower Zone of the intrusion. The cyclic units of the Middle Zone consist of magnetite gabbro and overlying gabbro. In these cyclic units, contents of Fe2O3(t), TiO2 and Cr and Fe3+/Ti4+ ratio of the rocks decrease upward, Cr content of magnetite and forsterite percentage of olivine decrease as well. The Upper Zone consists of apatite gabbro characterized by enrichment of incompatible elements (e.g., 12-18 ppm La, 20-28 ppm Y) and increasing of Fe3+/Ti4+ ratio (from 1.3 to 2.3) upward. These features indicate that the Panzhihua intrusion was repeatedly recharged by more primitive magma and evolved magmas had been extracted. Calculations using MELTS indicate that extensive fractionation of olivine and clinopyroxene in deep level resulted in increasing Fe and Ti contents in the magma. When these Fe-Ti-enriched magmas were emplaced along the base of the Panzhihua intrusion, Fe-Ti oxides became an early crystallization phase, leading to a residual magma of lower density. We propose that the unusually thick stratiform Fe-Ti oxide layers resulted from coupling of gravity settling and sorting of the crystallized Fe-Ti oxides from Fe-Ti-enriched magmas and frequent magma replenishment along the floor of the magma chamber.

  11. Mechanisms and timescales of generating eruptible rhyolitic magmas at Yellowstone caldera from zircon and sanidine geochronology and geochemistry

    Science.gov (United States)

    Stelten, Mark; Cooper, Kari M.; Vazquez, Jorge A.; Calvert, Andrew T.; Glessner, Justin G

    2015-01-01

    antecrystic zircons require a model where eruptible rhyolites are generated by extracting melt and zircons from a long-lived mush of immobile crystal-rich magma. In this process the larger sanidine crystals remain trapped in the locked crystal network. The extracted melts (plus antecrystic zircon) amalgamate into a liquid dominated (i.e., eruptible) magma body that is maintained as a physically distinct entity relative to the bulk of the long-lived crystal mush. Zircon surfaces and sanidines in each rhyolite crystallize after melt extraction/amalgamation and their ages constrain the residence time of eruptible magmas at Yellowstone. Residence times of the large volume rhyolites (~40 – 70 km3) are ≤ 1 kyr (conservatively < 6 kyr), which suggests that large volumes of rhyolite can be generated rapidly by extracting melt from a crystal mush. Because the lifespan of the crystal mush that sourced the Central Plateau Member rhyolites is two orders of magnitude longer than the residence time of eruptible magma bodies within the reservoir, it is apparent that the Yellowstone magma reservoir spends most of its time in a largely-crystalline (i.e., uneruptible) state, similar to the present-day magma reservoir, and that eruptible magma bodies are ephemeral features.

  12. Magma paths at Piton de la Fournaise Volcano

    OpenAIRE

    Michon , Laurent; Ferrazzini , Valérie; Di Muro , Andrea

    2016-01-01

    International audience; Several patterns of magma paths have been proposed since the 1980s for Piton de la Fournaise volcano. Given the significant differences, which are presented here, we propose a reappraisal of the magma intrusion paths using a 17-years-long database of volcano-tectonic seismic events and a detailed mapping of the scoria cones. At the edifice scale, the magma propagates along two N120 trending rift zones. They are wide, linear, spotted by small to large scoria cones and r...

  13. Magma Expansion and Fragmentation in a Propagating Dike (Invited)

    Science.gov (United States)

    Jaupart, C. P.; Taisne, B.

    2010-12-01

    The influence of magma expansion due to volatile exsolution and gas dilation on dike propagation is studied using a new numerical code. Many natural magmas contain sufficient amounts of volatiles for fragmentation to occur well below Earth's surface. Magma fragmentation has been studied for volcanic flows through open conduits but it should also occur within dikes that rise towards Earth's surface. We consider the flow of a volatile-rich magma in a hydraulic fracture. The mixture of melt and gas is treated as a compressible viscous fluid below the fragmentation level and as a gas phase carrying melt droplets above it. A numerical code solves for elastic deformation of host rocks, the flow of the magmatic mixture and fracturing at the dike tip. With volatile-free magma, a dike fed at a constant rate in a uniform medium adopts a constant shape and width and rises at a constant velocity. With volatiles involved, magma expands and hence the volume flux of magma increases. With no fragmentation, this enhanced flux leads to acceleration of the dike. Simple scaling laws allow accurate predictions of dike width and ascent rate for a wide range of conditions. With fragmentation, dike behavior is markedly different. Due to the sharp drop of head loss that occurs in gas-rich fragmented material, large internal overpressures develop below the tip and induce swelling of the nose region, leading to deceleration of the dike. Thus, the paradoxical result is that, with no viscous impediment on magma flow and a large buoyancy force, the dike stalls. This process may account for some of the tuffisite veins and intrusions that are found in and around magma conduits, notably in the Unzen drillhole, Japan. We apply these results to the two-month long period of volcanic unrest that preceded the May 1980 eruption of Mount St Helens. An initial phase of rapid earthquake migration from the 7-8 km deep reservoir to shallow levels was followed by very slow progression of magma within the

  14. Genesis of felsic plutonic magmas and their igneous enclaves

    DEFF Research Database (Denmark)

    Clemens, John D.; Maas, Roland; Waight, Tod Earle

    2016-01-01

    -type Pyalong pluton was emplaced, apparently along an east-west-orientated fracture zone. Around 367 Ma, the main I-type Baynton pluton intruded as numerous shallow-dipping sheets. The last plutonic event was the intrusion of the broad, thin, flat-lying, and crosscutting sheet of the I-type Beauvallet pluton...... the relatively high abundance of igneous-textured microgranular enclaves (MEs). The MEs show neither chemical nor isotope mixing trends with each other or with the host magmas. Variations in the Baynton magmas were derived from the heterogeneity of the source terrane, with individual magma batches formed from...

  15. Energy extracted from underground rock area by using a horizontal closed loop system in Mutah University/Jordan

    International Nuclear Information System (INIS)

    Al-Dabbas, Mohammed Awwad Ali; Al-Rousan, Ammar A.

    2013-01-01

    Highlights: ► The ground can be used as a storage tank to store hot or cooled water in Jordan. ► The stored energy in rocks was utilized to provide heating cooling, and hot water for homes. ► The underground geothermal horizontal loop in rocks was technically approved. ► It can extract up to six times the heat energy that used in electrical energy. ► Its low capital cost and zero environmental emissions. - Abstract: Earth Energy Systems (EESs) utilize the thermal energy that is stored in rocks and ground water under the earth’s surface to provide homes, commercial buildings, and industrial facilities with heating, cooling, and hot water. Solar energy is absorbed by the earth’s surface which stores up to 50% of the sun’s energy that radiates on it. Consequently, the earth and groundwater’s temperature is relatively constant compared to that of the surface air. The earth’s temperature is generally warmer than the surface temperature during the colder months of the year, while it is generally cooler than the surface temperature during the hot months of the year. In this study, energy was extracted from the underground rocks at Mutah University in Jordan by using the geothermal horizontal closed loop system. Two-meter holes were drilled into the earth’s surface; copper pipes were inserted for liquid to pass through them into the heat exchange system. Then, the liquid was circulated back into the ground. Several temperature differences were measured and reported in the cold and hot months. The experimental results showed that thermal energy stored in rocks can be used to provide homes with heating, cooling, and hot water with low capital cost and zero environmental emissions.

  16. Fault feature extraction of planet gear in wind turbine gearbox based on spectral kurtosis and time wavelet energy spectrum

    Science.gov (United States)

    Kong, Yun; Wang, Tianyang; Li, Zheng; Chu, Fulei

    2017-09-01

    Planetary transmission plays a vital role in wind turbine drivetrains, and its fault diagnosis has been an important and challenging issue. Owing to the complicated and coupled vibration source, time-variant vibration transfer path, and heavy background noise masking effect, the vibration signal of planet gear in wind turbine gearboxes exhibits several unique characteristics: Complex frequency components, low signal-to-noise ratio, and weak fault feature. In this sense, the periodic impulsive components induced by a localized defect are hard to extract, and the fault detection of planet gear in wind turbines remains to be a challenging research work. Aiming to extract the fault feature of planet gear effectively, we propose a novel feature extraction method based on spectral kurtosis and time wavelet energy spectrum (SK-TWES) in the paper. Firstly, the spectral kurtosis (SK) and kurtogram of raw vibration signals are computed and exploited to select the optimal filtering parameter for the subsequent band-pass filtering. Then, the band-pass filtering is applied to extrude periodic transient impulses using the optimal frequency band in which the corresponding SK value is maximal. Finally, the time wavelet energy spectrum analysis is performed on the filtered signal, selecting Morlet wavelet as the mother wavelet which possesses a high similarity to the impulsive components. The experimental signals collected from the wind turbine gearbox test rig demonstrate that the proposed method is effective at the feature extraction and fault diagnosis for the planet gear with a localized defect.

  17. An energy conservation approach to adsorbate-induced surface stress and the extraction of binding energy using nanomechanics

    Science.gov (United States)

    Pinnaduwage, Lal A.; Boiadjiev, Vassil I.; Hawk, John E.; Gehl, Anthony C.; Fernando, Gayanath W.; Rohana Wijewardhana, L. C.

    2008-03-01

    Surface stress induced by molecular adsorption in three different binding processes has been studied experimentally using a microcantilever sensor. A comprehensive free-energy analysis based on an energy conservation approach is proposed to explain the experimental observations. We show that when guest molecules bind to atoms/molecules on a microcantilever surface, the released binding energy is retained in the host surface, leading to a metastable state where the excess energy on the surface is manifested as an increase in surface stress leading to the bending of the microcantilever. The released binding energy appears to be almost exclusively channeled to the surface energy, and energy distribution to other channels, including heat, appears to be inactive for this micromechanical system. When this excess surface energy is released, the microcantilever relaxes back to the original state, and the relaxation time depends on the particular binding process involved. Such vapor phase experiments were conducted for three binding processes: physisorption, hydrogen bonding, and chemisorption. Binding energies for these three processes were also estimated.

  18. An energy conservation approach to adsorbate-induced surface stress and the extraction of binding energy using nanomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Pinnaduwage, Lal A; Boiadjiev, Vassil I; Hawk, John E; Gehl, Anthony C [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6122 (United States); Fernando, Gayanath W [Physics Department, University of Connecticut, Storrs, CT 06269 (United States); Wijewardhana, L C Rohana [Physics Department, University of Cincinnati, Cincinnati, OH 45221 (United States)

    2008-03-12

    Surface stress induced by molecular adsorption in three different binding processes has been studied experimentally using a microcantilever sensor. A comprehensive free-energy analysis based on an energy conservation approach is proposed to explain the experimental observations. We show that when guest molecules bind to atoms/molecules on a microcantilever surface, the released binding energy is retained in the host surface, leading to a metastable state where the excess energy on the surface is manifested as an increase in surface stress leading to the bending of the microcantilever. The released binding energy appears to be almost exclusively channeled to the surface energy, and energy distribution to other channels, including heat, appears to be inactive for this micromechanical system. When this excess surface energy is released, the microcantilever relaxes back to the original state, and the relaxation time depends on the particular binding process involved. Such vapor phase experiments were conducted for three binding processes: physisorption, hydrogen bonding, and chemisorption. Binding energies for these three processes were also estimated.

  19. Extracting integrated and differential cross sections in low energy heavy-ion reactions from backscattering measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sargsyan, V. V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Yerevan State University, 0025 Yerevan (Armenia); Adamian, G. G., E-mail: adamian@theor.jinr.ru [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Antonenko, N. V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Mathematical Physics Department, Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Diaz-Torres, A. [European Centre for Theoretical Studies in Nuclear Physics and Related Areas, I-38123 Villazzano, Trento (Italy); Gomes, P. R. S. [de Fisica, Universidade Federal Fluminense, Av. Litorânea, s/n, Niterói, R.J. 24210-340 (Brazil); Lenske, H. [Institut für Theoretische Physik der Justus–Liebig–Universität, D–35392 Giessen (Germany)

    2016-07-07

    We suggest new methods to extract elastic (quasi-elastic) scattering angular distribution and reaction (capture) cross sections from the experimental elastic (quasi-elastic) backscattering excitation function taken at a single angle.

  20. Extraction of topographic and material contrasts on surfaces from SEM images obtained by energy filtering detection with low-energy primary electrons.

    Science.gov (United States)

    Nagoshi, Masayasu; Aoyama, Tomohiro; Sato, Kaoru

    2013-01-01

    Secondary electron microscope (SEM) images have been obtained for practical materials using low primary electron energies and an in-lens type annular detector with changing negative bias voltage supplied to a grid placed in front of the detector. The kinetic-energy distribution of the detected electrons was evaluated by the gradient of the bias-energy dependence of the brightness of the images. This is divided into mainly two parts at about 500 V, high and low brightness in the low- and high-energy regions, respectively and shows difference among the surface regions having different composition and topography. The combination of the negative grid bias and the pixel-by-pixel image subtraction provides the band-pass filtered images and extracts the material and topographic information of the specimen surfaces. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Extraction of topographic and material contrasts on surfaces from SEM images obtained by energy filtering detection with low-energy primary electrons

    International Nuclear Information System (INIS)

    Nagoshi, Masayasu; Aoyama, Tomohiro; Sato, Kaoru

    2013-01-01

    Secondary electron microscope (SEM) images have been obtained for practical materials using low primary electron energies and an in-lens type annular detector with changing negative bias voltage supplied to a grid placed in front of the detector. The kinetic-energy distribution of the detected electrons was evaluated by the gradient of the bias-energy dependence of the brightness of the images. This is divided into mainly two parts at about 500 V, high and low brightness in the low- and high-energy regions, respectively and shows difference among the surface regions having different composition and topography. The combination of the negative grid bias and the pixel-by-pixel image subtraction provides the band-pass filtered images and extracts the material and topographic information of the specimen surfaces. -- Highlights: ► Scanning electron (SE) images contain many kind of information on material surfaces. ► We investigate energy-filtered SE images for practical materials. ► The brightness of the images is divided into two parts by the bias voltage. ► Topographic and material contrasts are extracted by subtracting the filtered images.

  2. Why Is There an Abrupt Transition from Solid Rock to Low Crystallinity Magma in Drilled Magma Bodies?

    Science.gov (United States)

    Eichelberger, J. C.; Carrigan, C. R.; Sun, Y.; Lavallée, Y.

    2017-12-01

    We report on a preliminary evaluation, from basic principles of heat and mass transfer, on the unexpectedly abrupt transition from cuttings of solid rock to fragments of crystal poor glass during drilling into magma bodies. Our analysis is based on conditions determined and inferred for the 2009 IDDP-1 well in Krafla Caldera, which entered apparently liquidus rhyolite magma at about 900oC at a depth of 2104 m. Simple conduction would predict some 30 m of crystallization and partial crystallization since the latest time the magma could have been intruded, approximately 30 years prior to discovery by drilling. Option 1: The expected crystallization of magma has occurred but interstitial melt remains. The pressure difference between lithostatic load of about 50 MPa on the mush and 20 MPa hydrostatic pressure in the well causes pore melt to flow from the permeable mush into the borehole, where it becomes the source of the quenched melt chips. To be viable, this mechanism must work over the time frame of a day. Option 2: The expected crystallization is occurring, but high Rayleigh number thermal convection in the magma chamber continuously displaces crystallizing roof magma by liquidus magma from the interior of the body. To be viable, this mechanism must result in overturning magma in the chamber on a time scale that is much shorter than that of crystallization. Option 3: Flow-induced crystal migration away from zones of high shear created during drilling into magma may preferentially produce low-crystal-content melt at the boundary of the borehole, which is then sampled.

  3. Formation of anorthosite on the Moon through magma ocean fractional crystallization

    Directory of Open Access Journals (Sweden)

    Tatsuyuki Arai

    2017-03-01

    Full Text Available Lunar anorthosite is a major rock of the lunar highlands, which formed as a result of plagioclase-floatation in the lunar magma ocean (LMO. Constraints on the sufficient conditions that resulted in the formation of a thick pure anorthosite (mode of plagioclase >95 vol.% is a key to reveal the early magmatic evolution of the terrestrial planets. To form the pure lunar anorthosite, plagioclase should have separated from the magma ocean with low crystal fraction. Crystal networks of plagioclase and mafic minerals develop when the crystal fraction in the magma (φ is higher than ca. 40–60 vol.%, which inhibit the formation of pure anorthosite. In contrast, when φ is small, the magma ocean is highly turbulent, and plagioclase is likely to become entrained in the turbulent magma rather than separated from the melt. To determine the necessary conditions in which anorthosite forms from the LMO, this study adopted the energy criterion formulated by Solomatov. The composition of melt, temperature, and pressure when plagioclase crystallizes are constrained by using MELTS/pMELTS to calculate the density and viscosity of the melt. When plagioclase starts to crystallize, the Mg# of melt becomes 0.59 at 1291 °C. The density of the melt is smaller than that of plagioclase for P > 2.1 kbar (ca. 50 km deep, and the critical diameter of plagioclase to separate from the melt becomes larger than the typical crystal diameter of plagioclase (1.8–3 cm. This suggests that plagioclase is likely entrained in the LMO just after the plagioclase starts to crystallize. When the Mg# of melt becomes 0.54 at 1263 °C, the density of melt becomes larger than that of plagioclase even for 0 kbar. When the Mg# of melt decreases down to 0.46 at 1218 °C, the critical diameter of plagioclase to separate from the melt becomes 1.5–2.5 cm, which is nearly equal to the typical plagioclase of the lunar anorthosite. This suggests that plagioclase could separate from the

  4. Water Partitioning in Planetary Embryos and Protoplanets with Magma Oceans

    Science.gov (United States)

    Ikoma, M.; Elkins-Tanton, L.; Hamano, K.; Suckale, J.

    2018-06-01

    The water content of magma oceans is widely accepted as a key factor that determines whether a terrestrial planet is habitable. Water ocean mass is determined as a result not only of water delivery and loss, but also of water partitioning among several reservoirs. Here we review our current understanding of water partitioning among the atmosphere, magma ocean, and solid mantle of accreting planetary embryos and protoplanets just after giant collisions. Magma oceans are readily formed in planetary embryos and protoplanets in their accretion phase. Significant amounts of water are partitioned into magma oceans, provided the planetary building blocks are water-rich enough. Particularly important but still quite uncertain issues are how much water the planetary building blocks contain initially and how water goes out of the solidifying mantle and is finally degassed to the atmosphere. Constraints from both solar-system explorations and exoplanet observations and also from laboratory experiments are needed to resolve these issues.

  5. Understanding the rheology of two and three-phase magmas

    Science.gov (United States)

    Coats, R.; Cai, B.; Kendrick, J. E.; Wallace, P. A.; Hornby, A. J.; Miwa, T.; von Aulock, F. W.; Ashworth, J. D.; Godinho, J.; Atwood, R. C.; Lee, P. D.; Lavallée, Y.

    2017-12-01

    The rheology of magma plays a fundamental role in determining the style of a volcanic eruption, be it explosive or effusive. Understanding how magmas respond to changes in stress/ strain conditions may help to enhance eruption forecast models. The presence of crystals and bubbles in magmas alter the viscosity of suspensions and favor a non-Newtonian response. Thus, with the aim of grasping the rheological behavior of volcanic materials, uniaxial compressive tests were performed on natural and synthetic samples. A suite of variably porous (10-32 vol.%), highly crystalline ( 50 vol.%) dacite from the 1991-95 eruption of Mt Unzen, Japan, was selected as the natural material, while synthetic samples were sintered with desired porosities (Diamond Light Source. Unexpectedly, these observations suggest that fractures nucleate in crystals due to crystal interactions, before propagating through the interstitial melt. This ongoing study promises to uncover the way crystal-bearing magmas flow or fail, necessary to constrain magmatic processes and volcanic hazards.

  6. Implications of magma transfer between multiple reservoirs on eruption cycling.

    Science.gov (United States)

    Elsworth, Derek; Mattioli, Glen; Taron, Joshua; Voight, Barry; Herd, Richard

    2008-10-10

    Volcanic eruptions are episodic despite being supplied by melt at a nearly constant rate. We used histories of magma efflux and surface deformation to geodetically image magma transfer within the deep crustal plumbing of the Soufrière Hills volcano on Montserrat, West Indies. For three cycles of effusion followed by discrete pauses, supply of the system from the deep crust and mantle was continuous. During periods of reinitiated high surface efflux, magma rose quickly and synchronously from a deflating mid-crustal reservoir (at about 12 kilometers) augmented from depth. During repose, the lower reservoir refilled from the deep supply, with only minor discharge transiting the upper chamber to surface. These observations are consistent with a model involving the continuous supply of magma from the deep crust and mantle into a voluminous and compliant mid-crustal reservoir, episodically valved below a shallow reservoir (at about 6 kilometers).

  7. Production and Preservation of Sulfide Layering in Mercury's Magma Ocean

    Science.gov (United States)

    Boukare, C.-E.; Parman, S. W.; Parmentier, E. M.; Anzures, B. A.

    2018-05-01

    Mercury's magma ocean (MMO) would have been sulfur-rich. At some point during MMO solidification, it likely became sulfide saturated. Here we present physiochemical models exploring sulfide layer formation and stability.

  8. Magma chamber processes in central volcanic systems of Iceland

    DEFF Research Database (Denmark)

    Þórarinsson, Sigurjón Böðvar; Tegner, Christian

    2009-01-01

    are composed of 2-10 m thick melanocratic layers rich in clinopyroxene and sometimes olivine, relative to the thicker overlying leucocratic oxide gabbros. While the overall compositional variation is limited (Mg# clinopyroxene 72-84; An% plagioclase 56-85), the melanocratic bases display spikes in Mg# and Cr2O......3 of clinopyroxene and magnetite indicative of magma replenishment. Some macrorhythmic units show mineral trends indicative of up-section fractional crystallisation over up to 100 m, whereas others show little variation. Two populations of plagioclase crystals (large, An-rich and small, less An......-rich) indicate that the recharge magma carried plagioclase xenocrysts (high An-type). The lack of evolved gabbros suggests formation in a dynamic magma chamber with frequent recharge, tapping and fractionation. Modelling of these compositional trends shows that the parent magma was similar to known transitional...

  9. Seismic Tremors and Three-Dimensional Magma Wagging

    Science.gov (United States)

    Liao, Y.; Bercovici, D.

    2015-12-01

    Seismic tremor is a feature shared by many silicic volcanoes and is a precursor of volcanic eruption. Many of the characteristics of tremors, including their frequency band from 0.5 Hz to 7 Hz, are common for volcanoes with very different geophysical and geochemical properties. The ubiquitous characteristics of tremor imply that it results from some generation mechanism that is common to all volcanoes, instead of being unique to each volcano. Here we present new analysis on the magma-wagging mechanism that has been proposed to generate tremor. The model is based on the suggestion given by previous work (Jellinek & Bercovici 2011; Bercovici et.al. 2013) that the magma column is surrounded by a compressible, bubble-rich foam annulus while rising inside the volcanic conduit, and that the lateral oscillation of the magma inside the annulus causes observable tremor. Unlike the previous two-dimensional wagging model where the displacement of the magma column is restricted to one vertical plane, the three-dimensional model we employ allows the magma column to bend in different directions and has angular motion as well. Our preliminary results show that, without damping from viscous deformation of the magma column, the system retains angular momentum and develops elliptical motion (i.e., the horizontal displacement traces an ellipse). In this ''inviscid'' limit, the magma column can also develop instabilities with higher frequencies than what is found in the original two-dimensional model. Lateral motion can also be out of phase for various depths in the magma column leading to a coiled wagging motion. For the viscous-magma model, we predict a similar damping rate for the uncoiled magma column as in the two-dimensional model, and faster damping for the coiled magma column. The higher damping thus requires the existence of a forcing mechanism to sustain the oscillation, for example the gas-driven Bernoulli effect proposed by Bercovici et al (2013). Finally, using our new 3

  10. Magma chamber interaction giving rise to asymmetric oscillations

    Science.gov (United States)

    Walwer, D.; Ghil, M.; Calais, E.

    2017-12-01

    Geodetic time series at four volcanoes (Okmok, Akutan, Shishaldin, and Réunion) are processed using Multi-channel Singular Spectrum Analysis (M-SSA) and reveal sawtooth-shaped oscillations ; the latter are characterized by short intervals of fast inflations followed by longer intervals of slower deflations. At Okmok and Akutan, the oscillations are first damped and then accentuated. At Okmok, the increase in amplitude of the oscillations is followed by an eruption. We first show that the dynamics of these four volcanoes bears similarities with that of a simple nonlinear, dissipative oscillator, indicating that the inflation-deflation episodes are relaxation oscillations. These observations imply that ab initio dynamical models of magma chambers should possess an asymmetric oscillatory regime. Next, based on the work of Whitehead and Helfrich [1991], we show that a model of two magma chambers — connected by a cylindrical conduit in which the magma viscosity depends on temperature — gives rise to asymmetric overpressure oscillations in the magma reservoirs. These oscillations lead to surface deformations that are consistent with those observed at the four volcanoes in this study. This relaxation oscillation regime occurs only when the vertical temperature gradient in the host rock between the two magma chambers is large enough and when the magma flux entering the volcanic system is sufficiently high. The magma being supplied by a deeper source region, the input flux depends on the pressure difference between the source and the deepest reservoir. When this difference is not sufficiently high, the magma flux exponentially decreases, leading to damped oscillations as observed at Akutan and Okmok. The combination of observational and modeling results clearly supports the role of relaxation oscillations in the dynamics of volcanic systems.

  11. Experimental Fractional Crystallization of the Lunar Magma Ocean

    Science.gov (United States)

    Rapp, J. F.; Draper, D. S.

    2012-01-01

    The current paradigm for lunar evolution is of crystallization of a global scale magma ocean, giving rise to the anorthositic crust and mafic cumulate interior. It is thought that all other lunar rocks have arisen from this differentiated interior. However, until recently this paradigm has remained untested experimentally. Presented here are the first experimental results of fractional crystallization of a Lunar Magma Ocean (LMO) using the Taylor Whole Moon (TWM) bulk lunar composition [1].

  12. The fluid dynamics of a basaltic magma chamber replenished by influx of hot, dense ultrabasic magma

    Science.gov (United States)

    Huppert, Herbert E.; Sparks, R. Stephen J.

    1981-09-01

    This paper describes a fluid dynamical investigation of the influx of hot, dense ultrabasic magma into a reservoir containing lighter, fractionated basaltic magma. This situation is compared with that which develops when hot salty water is introduced under cold fresh water. Theoretical and empirical models for salt/water systems are adapted to develop a model for magmatic systems. A feature of the model is that the ultrabasic melt does not immediately mix with the basalt, but spreads out over the floor of the chamber, forming an independent layer. A non-turbulent interface forms between this layer and the overlying magma layer across which heat and mass are transferred by the process of molecular diffusion. Both layers convect vigorously as heat is transferred to the upper layer at a rate which greatly exceeds the heat lost to the surrounding country rock. The convection continues until the two layers have almost the same temperature. The compositions of the layers remain distinct due to the low diffusivity of mass compared to heat. The temperatures of the layers as functions of time and their cooling rate depend on their viscosities, their thermal properties, the density difference between the layers and their thicknesses. For a layer of ultrabasic melt (18% MgO) a few tens of metres thick at the base of a basaltic (10% MgO) magma chamber a few kilometres thick, the temperature of the layers will become nearly identical over a period of between a few months and a few years. During this time the turbulent convective velocities in the ultrabasic layer are far larger than the settling velocity of olivines which crystallise within the layer during cooling. Olivines only settle after the two layers have nearly reached thermal equilibrium. At this stage residual basaltic melt segregates as the olivines sediment in the lower layer. Depending on its density, the released basalt can either mix convectively with the overlying basalt layer, or can continue as a separate

  13. Insecticidal effects of Moroccan plant extracts on development, energy reserves and enzymatic activities of Plodia interpunctella

    Energy Technology Data Exchange (ETDEWEB)

    Bouayard, N.; Rharrabe, K.; Ghailani, N. N.; Jbilou, R.; Castanera, P.; Ortego, F.

    2013-05-01

    The aim of this work was to study the effects of methanol extracts of ten plant species used in traditional medicine in Morocco (Peganum harmala, Ajuga iva, Rosmarinus officinalis, Lavandula stoechas, Lavandula dentata, Cistus ladanifer, Cistus salviaefolius, Cistus monspeliensis, Centaurium erythraea and Launaea arborescens) on Plodia interpunctella Hubner (Lepidoptera: Pyralidae) larvae. Firstly, we studied the effects of the ingestion of these extracts at 500 ppm on post-embryonic development parameters. Most plant extracts provoked a notable decrease of larval weight 8 days after treatment (up to 33% weight loss with C. erythraea) and caused significant alterations on pupation (ranging from 5% to 85%) and adult emergence (below 2.5% with R. officinalis, C. erythraea and A. iva). The plant extracts that showed strongest effects on post-embryonic development were selected to test their effects on the following physiological parameters: larval reserve substances (at 500 ppm); and midgut activities of hydrolytic and detoxification enzymes (at 500, 750 and 1000 ppm). All treatments provoked a significant reduction of protein and carbon hydrate larval contents, the inhibition of proteases and {alpha}-amylase activities in a dose depended manner, and the induction of glutathione S-transferase and esterase (using MtB as substrate) activities, whereas the activity of cytochrome P450 monooxygenases and esterases (using 1-NA as substrate) increase or decrease depending on the extract concentration and the plant analyzed. (Author) 65 refs.

  14. Insecticidal effects of Moroccan plant extracts on development, energy reserves and enzymatic activities of Plodia interpunctella

    Directory of Open Access Journals (Sweden)

    N. Bouayad

    2012-10-01

    Full Text Available The aim of this work was to study the effects of methanol extracts of ten plant species used in traditional medicine in Morocco (Peganum harmala, Ajuga iva, Rosmarinus officinalis, Lavandula stoechas, Lavandula dentata, Cistus ladanifer, Cistus salviaefolius, Cistus monspeliensis, Centaurium erythraea and Launaea arborescens on Plodia interpunctella Hübner (Lepidoptera: Pyralidae larvae. Firstly, we studied the effects of the ingestion of these extracts at 500 ppm on post-embryonic development parameters. Most plant extracts provoked a notable decrease of larval weight 8 days after treatment (up to 33% weight loss with C. erythraea and caused significant alterations on pupation (ranging from 5% to 85% and adult emergence (below 2.5% with R. officinalis, C. erythraea and A. iva. The plant extracts that showed strongest effects on post-embryonic development were selected to test their effects on the following physiological parameters: larval reserve substances (at 500 ppm; and midgut activities of hydrolytic and detoxification enzymes (at 500, 750 and 1000 ppm. All treatments provoked a significant reduction of protein and carbon hydrate larval contents, the inhibition of proteases and α-amylase activities in a dose depended manner, and the induction of glutathione S-transferase and esterase (using MtB as substrate activities, whereas the activity of cytochrome P450 monooxygenases and esterases (using 1-NA as substrate increase or decrease depending on the extract concentration and the plant analyzed.

  15. Performance Modeling of Mimosa pudica Extract as a Sensitizer for Solar Energy Conversion

    Directory of Open Access Journals (Sweden)

    M. B. Shitta

    2016-01-01

    Full Text Available An organic material is proposed as a sustainable sensitizer and a replacement for the synthetic sensitizer in a dye-sensitized solar cell technology. Using the liquid extract from the leaf of a plant called Mimosa pudica (M. pudica as a sensitizer, the performance characteristics of the extract of M. pudica are investigated. The photo-anode of each of the solar cell sample is passivated with a self-assembly monolayer (SAM from a set of four materials, including alumina, formic acid, gelatine, and oxidized starch. Three sets of five samples of an M. pudica–based solar cell are produced, with the fifth sample used as the control experiment. Each of the solar cell samples has an active area of 0.3848cm2. A two-dimensional finite volume method (FVM is used to model the transport of ions within the monolayer of the solar cell. The performance of the experimentally fabricated solar cells compares qualitatively with the ones obtained from the literature and the simulated solar cells. The highest efficiency of 3% is obtained from the use of the extract as a sensitizer. It is anticipated that the comparison of the performance characteristics with further research on the concentration of M. pudica extract will enhance the development of a reliable and competitive organic solar cell. It is also recommended that further research should be carried out on the concentration of the extract and electrolyte used in this study for a possible improved performance of the cell.

  16. Energy and Technology Review

    International Nuclear Information System (INIS)

    1984-05-01

    Three articles and two briefs discuss ongoing research at Lawrence Livermore National Laboratory. Topics in this issue include: construction of human chromosome library (brief); dispersion of liquified gases (brief); magma evolution; energy flow diagrams; and computer simulation of particulate flow

  17. Crystallization of a compositionally stratified basal magma ocean

    Science.gov (United States)

    Laneuville, Matthieu; Hernlund, John; Labrosse, Stéphane; Guttenberg, Nicholas

    2018-03-01

    Earth's ∼3.45 billion year old magnetic field is regenerated by dynamo action in its convecting liquid metal outer core. However, convection induces an isentropic thermal gradient which, coupled with a high core thermal conductivity, results in rapid conducted heat loss. In the absence of implausibly high radioactivity or alternate sources of motion to drive the geodynamo, the Earth's early core had to be significantly hotter than the melting point of the lower mantle. While the existence of a dense convecting basal magma ocean (BMO) has been proposed to account for high early core temperatures, the requisite physical and chemical properties for a BMO remain controversial. Here we relax the assumption of a well-mixed convecting BMO and instead consider a BMO that is initially gravitationally stratified owing to processes such as mixing between metals and silicates at high temperatures in the core-mantle boundary region during Earth's accretion. Using coupled models of crystallization and heat transfer through a stratified BMO, we show that very high temperatures could have been trapped inside the early core, sequestering enough heat energy to run an ancient geodynamo on cooling power alone.

  18. CHANGE OF PARADIGM IN UNDERGROUND HARD COAL MINING THROUGH EXTRACTION AND CAPITALIZATION OF METHANE FOR ENERGY PRODUCTION

    Directory of Open Access Journals (Sweden)

    Valeriu PLESEA

    2014-05-01

    Full Text Available Besides oil and gas, coal is the most important fossil fuel for energy production. Of the energy mixture of our country, the internal production gas share is 80% of the required annual consumption, of about 14 billion cubic meters, the rest of 20% being insured by importing, by the Russian company Gazprom. The share of coal in the National Power System (NPS is of 24% and is one of the most profitable energy production sources, taking into account the continuous increase of gas price and its dependence on external suppliers. Taking into account the infestation of the atmosphere and global warming as effect of important release of greenhouse gas and carbon dioxide as a result of coal burning for energy production in thermal power plants, there is required to identify new solutions for keeping the environment clean. Such a solution is presented in the study and analysis shown in the paper and is the extraction and capitalization of methane from the coal deposits and the underground spaces remaining free after mine closures. Underground methane extraction is considered even more opportune because, during coal exploitation, large quantities of such combustible gas are released and exhausted into the atmosphere by the degasification and ventilation stations from the surface, representing and important pollution factor for the environment, as greenhouse gas with high global warming potential (high GWP of about 21 times higher than carbon dioxide.

  19. Re-appraisal of the Magma-rich versus Magma-poor Paradigm at Rifted Margins: consequences for breakup processes

    Science.gov (United States)

    Tugend, J.; Gillard, M.; Manatschal, G.; Nirrengarten, M.; Harkin, C. J.; Epin, M. E.; Sauter, D.; Autin, J.; Kusznir, N. J.; McDermott, K.

    2017-12-01

    Rifted margins are often classified based on their magmatic budget only. Magma-rich margins are commonly considered to have excess decompression melting at lithospheric breakup compared with steady state seafloor spreading while magma-poor margins have suppressed melting. New observations derived from high quality geophysical data sets and drill-hole data have revealed the diversity of rifted margin architecture and variable distribution of magmatism. Recent studies suggest, however, that rifted margins have more complex and polyphase tectono-magmatic evolutions than previously assumed and cannot be characterized based on the observed volume of magma alone. We compare the magmatic budget related to lithospheric breakup along two high-resolution long-offset deep reflection seismic profiles across the SE-Indian (magma-poor) and Uruguayan (magma-rich) rifted margins. Resolving the volume of magmatic additions is difficult. Interpretations are non-unique and several of them appear plausible for each case involving variable magmatic volumes and mechanisms to achieve lithospheric breakup. A supposedly 'magma-poor' rifted margin (SE-India) may show a 'magma-rich' lithospheric breakup whereas a 'magma-rich' rifted margin (Uruguay) does not necessarily show excess magmatism at lithospheric breakup compared with steady-state seafloor spreading. This questions the paradigm that rifted margins can be subdivided in either magma-poor or magma-rich margins. The Uruguayan and other magma-rich rifted margins appear characterized by an early onset of decompression melting relative to crustal breakup. For the converse, where the onset of decompression melting is late compared with the timing of crustal breakup, mantle exhumation can occur (e.g. SE-India). Our work highlights the difficulty in determining a magmatic budget at rifted margins based on seismic reflection data alone, showing the limitations of margin classification based solely on magmatic volumes. The timing of

  20. Silica-enriched mantle sources of subalkaline picrite-boninite-andesite island arc magmas

    Science.gov (United States)

    Bénard, A.; Arculus, R. J.; Nebel, O.; Ionov, D. A.; McAlpine, S. R. B.

    2017-02-01

    Primary arc melts may form through fluxed or adiabatic decompression melting in the mantle wedge, or via a combination of both processes. Major limitations to our understanding of the formation of primary arc melts stem from the fact that most arc lavas are aggregated blends of individual magma batches, further modified by differentiation processes in the sub-arc mantle lithosphere and overlying crust. Primary melt generation is thus masked by these types of second-stage processes. Magma-hosted peridotites sampled as xenoliths in subduction zone magmas are possible remnants of sub-arc mantle and magma generation processes, but are rarely sampled in active arcs. Published studies have emphasised the predominantly harzburgitic lithologies with particularly high modal orthopyroxene in these xenoliths; the former characteristic reflects the refractory nature of these materials consequent to extensive melt depletion of a lherzolitic protolith whereas the latter feature requires additional explanation. Here we present major and minor element data for pristine, mantle-derived, lava-hosted spinel-bearing harzburgite and dunite xenoliths and associated primitive melts from the active Kamchatka and Bismarck arcs. We show that these peridotite suites, and other mantle xenoliths sampled in circum-Pacific arcs, are a distinctive peridotite type not found in other tectonic settings, and are melting residues from hydrous melting of silica-enriched mantle sources. We explore the ability of experimental studies allied with mantle melting parameterisations (pMELTS, Petrolog3) to reproduce the compositions of these arc peridotites, and present a protolith ('hybrid mantle wedge') composition that satisfies the available constraints. The composition of peridotite xenoliths recovered from erupted arc magmas plausibly requires their formation initially via interaction of slab-derived components with refractory mantle prior to or during the formation of primary arc melts. The liquid

  1. Estimates of volume and magma input in crustal magmatic systems from zircon geochronology: the effect of modelling assumptions and system variables

    Directory of Open Access Journals (Sweden)

    Luca eCaricchi

    2016-04-01

    Full Text Available Magma fluxes in the Earth’s crust play an important role in regulating the relationship between the frequency and magnitude of volcanic eruptions, the chemical evolution of magmatic systems and the distribution of geothermal energy and mineral resources on our planet. Therefore, quantifying magma productivity and the rate of magma transfer within the crust can provide valuable insights to characterise the long-term behaviour of volcanic systems and to unveil the link between the physical and chemical evolution of magmatic systems and their potential to generate resources. We performed thermal modelling to compute the temperature evolution of crustal magmatic intrusions with different final volumes assembled over a variety of timescales (i.e., at different magma fluxes. Using these results, we calculated synthetic populations of zircon ages assuming the number of zircons crystallising in a given time period is directly proportional to the volume of magma at temperature within the zircon crystallisation range. The statistical analysis of the calculated populations of zircon ages shows that the mode, median and standard deviation of the populations varies coherently as function of the rate of magma injection and final volume of the crustal intrusions. Therefore, the statistical properties of the population of zircon ages can add useful constraints to quantify the rate of magma injection and the final volume of magmatic intrusions.Here, we explore the effect of different ranges of zircon saturation temperature, intrusion geometry, and wall rock temperature on the calculated distributions of zircon ages. Additionally, we determine the effect of undersampling on the variability of mode, median and standards deviation of calculated populations of zircon ages to estimate the minimum number of zircon analyses necessary to obtain meaningful estimates of magma flux and final intrusion volume.

  2. Entomocidal activity of microwave energy & some aqueous plant extracts against Tribolium castaneum Herbst & Trogoderma granarium Everts

    Science.gov (United States)

    Agha, W. N. A.; Amin, A. H.; Khidr, S. K.; Ismail, A. Y.

    2017-09-01

    A laboratory experiment was conducted in order to evaluate the efficacy of microwave radiation and aqueous plant extracts against red flour beetle Tribolium castaneum & khapra beetle Trogoderma granarium. The larvae stage with dried fruits (black raisin, red raisin, fig and apricot) were subjected to microwave radiation at different power levels (280,560 and 840) watt for three exposure times (10, 30 and 50) seconds. Mortalities increased with an increase of concentration or exposure time or both. Thus, highest mortality 90% was achieved at 840 watt power output and exposure time 50 second for both aforementioned species. Likewise, eucalyptus Eucalyptus camaldulensis, mint Mentha canadensis and myrtle Myrtus communis were studied for their toxicity effect on mortality of larval stage at three dosages (12500, 25000 and 50000) ppm for different exposure times (1, 2, 3 and 7) days. The larvae of khapra beetle were more resistant to the insecticidal activity of plant extracts in comparison with red flour beetle larvae. The LC50 values were varied in accordance to plant extracts types and concentrations within the four interval times of exposure. The LC50 values for both khapra & red flour beetles were (47234.07 & 5760.90) ppm respectively on black raisin after 7 days exposure to eucalyptus aqueous extract.

  3. Production of zero energy radioactive beams through extraction across superfluid helium surface

    NARCIS (Netherlands)

    Takahashi, N; Huang, WX; Gloos, K; Dendooven, P; Pekola, JP; Aysto, J

    A radioactive Ra-223 source was immersed in superfluid helium at 1.2-1.7 K. Electric fields transported recoiled Rn-219 ions in the form of snowballs to the surface and further extracted them across the surface. The ions were focussed onto an aluminium foil and alpha particle spectra were taken with

  4. A cascade of magmatic events during the assembly and eruption of a super-sized magma body

    Science.gov (United States)

    Allan, Aidan. S. R.; Barker, Simon J.; Millet, Marc-Alban; Morgan, Daniel J.; Rooyakkers, Shane M.; Schipper, C. Ian; Wilson, Colin J. N.

    2017-07-01

    We use comprehensive geochemical and petrological records from whole-rock samples, crystals, matrix glasses and melt inclusions to derive an integrated picture of the generation, accumulation and evacuation of 530 km3 of crystal-poor rhyolite in the 25.4 ka Oruanui supereruption (New Zealand). New data from plagioclase, orthopyroxene, amphibole, quartz, Fe-Ti oxides, matrix glasses, and plagioclase- and quartz-hosted melt inclusions, in samples spanning different phases of the eruption, are integrated with existing data to build a history of the magma system prior to and during eruption. A thermally and compositionally zoned, parental crystal-rich (mush) body was developed during two periods of intensive crystallisation, 70 and 10-15 kyr before the eruption. The mush top was quartz-bearing and as shallow as 3.5 km deep, and the roots quartz-free and extending to >10 km depth. Less than 600 year prior to the eruption, extraction of large volumes of 840 °C low-silica rhyolite melt with some crystal cargo (between 1 and 10%), began from this mush to form a melt-dominant (eruptible) body that eventually extended from 3.5 to 6 km depth. Crystals from all levels of the mush were entrained into the eruptible magma, as seen in mineral zonation and amphibole model pressures. Rapid translation of crystals from the mush to the eruptible magma is reflected in textural and compositional diversity in crystal cores and melt inclusion compositions, versus uniformity in the outermost rims. Prior to eruption the assembled eruptible magma body was not thermally or compositionally zoned and at temperatures of 790 °C, reflecting rapid cooling from the 840 °C low-silica rhyolite feedstock magma. A subordinate but significant volume (3-5 km3) of contrasting tholeiitic and calc-alkaline mafic material was co-erupted with the dominant rhyolite. These mafic clasts host crystals with compositions which demonstrate that there was some limited pre-eruptive physical interaction of mafic

  5. Design Analysis of Power Extracting Unit of an Onshore OWC Based Wave Energy Power Plant using Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Zahid Suleman

    2011-07-01

    Full Text Available This research paper describes design and analysis of power extracting unit of an onshore OWC (Oscillating Water Column based wave energy power plant of capacity about 100 kilowatts. The OWC is modeled as solid piston of a reciprocating pump. The power extracting unit is designed analytically by using the theory of reciprocating pumps and principles of fluid mechanics. Pro-E and ANSYS workbench softwares are used to verify the analytical design. The analytical results of the flow velocity in the turbine duct are compared with the simulation results. The results are found to be in good agreement with each other. The results achieved by this research would finally assist in the overall design of the power plant which is the ultimate goal of this research work.

  6. Feasibility study of tuned liquid column damper for ocean wave energy extraction

    Science.gov (United States)

    Wong, Yihong; King, Yeong-Jin; Lai, An-Chow; Chong, Kok-Keong; Lim, Boon-Han

    2017-04-01

    Intermittent nature and low efficiency are the major issues in renewable energy supply. To overcome these issues, one of the possible methods is through a hybrid system where multiple sources of renewable energy are combined to compensate each other's weaknesses. The hybrid of solar energy and wave energy becomes possible through the introduction of a stable floating platform which enables solar energy generation above it and wave energy harvesting underneath it. This paper is intended to study the feasibility of harnessing ocean wave energy using a tuned liquid column damper (TLCD), a type of passive damping device that is designed to suppress externally induced vibration force at a specific frequency range. The proposed TLCD is to be implemented within a floating offshore structure to serve as a vibration mitigating mechanism by reducing the dynamic response of the structure and simultaneously utilize the flowing motion of liquid within the TLCD for generating electricity. The constructed TLCD prototype is tuned according to theoretical study and tested using a shaking table with a predetermined frequency range. The oscillating motion of water within the TLCD and the potential of installation of hydro turbine generator in term of recoverable amount of energy are studied.

  7. Petrology of the 1995/2000 Magma of Copahue, Argentina

    Science.gov (United States)

    Goss, A.; Varekamp, J. C.

    2001-05-01

    Phreatomagmatic eruptions of Copahue in July/August,1995 and July/August 2000 produced mixed juvenile clasts, silica-rich debris from the hydrothermal system, and magmatic scoria with 88 percent SiO2. These high-SiO2 clasts carry an as yet unidentified (crystobalite?), euhedral silica phase in great abundance, which is riddled with tan, primary melt inclusions. The mixed clasts have bands of mafic material with small euhedral olivine, clinopyroxene, and plagioclase that are mixed with an intermediate magma with coarser, resorbed phenocrysts of olivine, plagioclase, clino- and ortho- pyroxene, and rare occurrences of the silica phase. These ejecta are intimate mixtures of a relatively felsic magma similar to Pleistocene Copahue lavas and a mafic basaltic andesite, with minor contributions of a magma contaminated with silica-rich hydrothermal wallrock material. Two-pyroxene geothermometry indicates crystallization temperatures of 1020 deg - 1045 deg C. Glass inclusions (59-63 percent SiO2) in plagioclase and olivine crystals yield very low volatile contents in the melt (0.4-1.5 percent H2O). The 1995/2000 magmas resided at shallow level and degassed into the active volcano-hydrothermal system which discharges acid fluids into the Copahue crater lake and hot springs. More mafic magma intruded this shallow batch and the mixture rose into the hydrothermal system and assimilated siliceous wall rock. A Ti-diffusion profile in a magnetite crystal suggests that the period between magma mixing and eruption was on the order of 4-10 weeks, and the temperature difference between resident and intruding magma was about 50-60 oC.

  8. Energy extraction from a semi-passive flapping-foil turbine with active heave and passive pitch

    Science.gov (United States)

    Boudreau, Matthieu; Dumas, Guy; Gunther, Kevin; CFD Laboratory LMFN Team

    2017-11-01

    Due to the inherent complexity of the mechanisms needed to prescribe the heaving and the pitching motions of optimal flapping-foil turbines, several research groups are now investigating the potential of using unconstrained passive motions. The amplitude, the phase and the frequency of such free motions are thus the result of the interaction of the blade with the flow and its elastic supports, namely springs and dampers. In parallel with our current study on fully-passive flapping-foil turbines, we investigate in this work the possibility of using a semi-passive turbine. Unlike previous semi-passive turbines studied in the literature, we propose a turbine with a passive pitching motion and an active heaving motion constrained to be a sine wave with desired amplitude and frequency. As most of the energy extracted by flapping-foil turbines comes from the heaving motion, it is natural to connect an electric generator to this degree of freedom, thereby allowing one to constrain this motion. It is found that large-amplitude pitching motions leading to a considerable energy extraction can arise under different circumstances and mechanisms, either forced by the heaving motion or driven by an instability of the pitching motion itself. The authors gratefully acknowledge the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Tyler Lewis Clean Energy Research Foundation, Calcul Québec and Compute Canada.

  9. Extraction of ultra-low-energy antiprotons from the PS200 catching trap for atomic physics experiments

    International Nuclear Information System (INIS)

    Holzscheiter, M.H.

    1996-01-01

    Approximately one million antiprotons have been captured in a large-scale Penning trap at the low energy antiproton ring at CERN. Up to 65% of the captured antiprotons have subsequently been cooled by electron cooling to energies below 1 eV and have been stored up to one hour. This has opened new discussions of the possible use of ultra-low-energy antiprotons for nuclear, atomic, and gravitational physics. For most of these experiments it will be necessary to extract the antiprotons from the trap in the form of either a continuous beam or as a bunched beam, allowing the timing structure to be used for post-acceleration schemes or as a time tag for subsequent measurements. We have designed an extraction scheme to accomplish this and have tested portions of it using a smaller-scale Penning trap loaded with protons. First results in generating a time-correlated beam of particles from a Penning trap are presented. (orig.)

  10. Potential environmental impact of tidal energy extraction in the Pentland Firth at large spatial scales: results of a biogeochemical model

    Science.gov (United States)

    van der Molen, Johan; Ruardij, Piet; Greenwood, Naomi

    2016-05-01

    A model study was carried out of the potential large-scale (> 100 km) effects of marine renewable tidal energy generation in the Pentland Firth, using the 3-D hydrodynamics-biogeochemistry model GETM-ERSEM-BFM. A realistic 800 MW scenario and a high-impact scenario with massive expansion of tidal energy extraction to 8 GW scenario were considered. The realistic 800 MW scenario suggested minor effects on the tides, and undetectable effects on the biogeochemistry. The massive-expansion 8 GW scenario suggested effects would be observed over hundreds of kilometres away with changes of up to 10 % in tidal and ecosystem variables, in particular in a broad area in the vicinity of the Wash. There, waters became less turbid, and primary production increased with associated increases in faunal ecosystem variables. Moreover, a one-off increase in carbon storage in the sea bed was detected. Although these first results suggest positive environmental effects, further investigation is recommended of (i) the residual circulation in the vicinity of the Pentland Firth and effects on larval dispersal using a higher-resolution model and (ii) ecosystem effects with (future) state-of-the-art models if energy extraction substantially beyond 1 GW is planned.

  11. Energy consumption in desalinating produced water from shale oil and gas extraction

    OpenAIRE

    Tow, Emily W.; Chung, Hyung Won; Lienhard, John H.; Thiel, Gregory Parker; Banchik, Leonardo David

    2014-01-01

    On-site treatment and reuse is an increasingly preferred option for produced water management in unconventional oil and gas extraction. This paper analyzes and compares the energetics of several desalination technologies at the high salinities and diverse compositions commonly encountered in produced water from shale formations to guide technology selection and to inform further system development. Produced water properties are modeled using Pitzer's equations, and emphasis is placed on how t...

  12. Investigation on the possibility of extracting wave energy from the Texas coast

    Science.gov (United States)

    Haces-Fernandez, Francisco

    Due to the great and growing demand of energy consumption in the Texas Coast area, the generation of electricity from ocean waves is considered very important. The combination of the wave energy with offshore wind power is explored as a way to increase power output, obtain synergies, maximize the utilization of assigned marine zones and reduce variability. Previously literature has assessed the wave energy generation, combined with wind in different geographic locations such as California, Ireland and the Azores Island. In this research project, the electric power generation from ocean waves on the Texas Coast was investigated, assessing its potential from the meteorological data provided by five buoys from National Data Buoy Center of the National Oceanic and Atmospheric Administration, considering the Pelamis 750 kW Wave Energy Converter (WEC) and the Vesta V90 3 MW Wind Turbine. The power output from wave energy was calculated for the year 2006 using Matlab, and the results in several locations were considered acceptable in terms of total power output, but with a high temporal variability. To reduce its variability, wave energy was combined with wind energy, obtaining a significant reduction on the coefficient of variation on the power output. A Matlab based interface was created to calculate power output and its variability considering data from longer periods of time.

  13. Energy Extraction Resistors for the Main Dipole and Quadrupole Circuits of the LHC

    CERN Document Server

    Dahlerup-Petersen, K; Popov, V; Sytchev, V V; Vasilev, L B; Zubko, V G

    2000-01-01

    When the LHC will be operating at its maximum beam energy, its superconducting dipole chains store a total magnetic energy of more than 11 GJ. At the same time, the QF and QD quadrupole circuits store a total energy of 400 MJ. Even with the sectorisation of each of the three principal power circuits into eight individually powered segments, the stored energy of a single circuit is considerable. During normal operation the energy in the dipole circuits is safely returned to the mains grid, using the thyristor-based, 'booster' unit of the power converters, operating in inversion. For the quadrupole chains, where the converter is of a mono-polar topology, the stored energy is dissipated into the resistive part of the warm d.c. power lines (busbars and cables) in a slow, controlled run-down. When a magnet quenches, however, such a slow energy transfer, taking 20 minutes from the rated LHC current, will not be possible. The 'cold' diode, taking over the magnet current in case of a quench, will not survive this slo...

  14. Carbon dioxide in magmas and implications for hydrothermal systems

    Science.gov (United States)

    Lowenstern, J. B.

    2001-01-01

    This review focuses on the solubility, origin, abundance, and degassing of carbon dioxide (CO2) in magma-hydrothermal systems, with applications for those workers interested in intrusion-related deposits of gold and other metals. The solubility of CO2 increases with pressure and magma alkalinity. Its solubility is low relative to that of H2O, so that fluids exsolved deep in the crust tend to have high CO2/H2O compared with fluids evolved closer to the surface. Similarly, CO2/H2O will typically decrease during progressive decompression- or crystallization-induced degassing. The temperature dependence of solubility is a function of the speciation of CO2, which dissolves in molecular form in rhyolites (retrograde temperature solubility), but exists as dissolved carbonate groups in basalts (prograde). Magnesite and dolomite are stable under a relatively wide range of mantle conditions, but melt just above the solidus, thereby contributing CO2 to mantle magmas. Graphite, diamond, and a free CO2-bearing fluid may be the primary carbon-bearing phases in other mantle source regions. Growing evidence suggests that most CO2 is contributed to arc magmas via recycling of subducted oceanic crust and its overlying sediment blanket. Additional carbon can be added to magmas during magma-wallrock interactions in the crust. Studies of fluid and melt inclusions from intrusive and extrusive igneous rocks yield ample evidence that many magmas are vapor saturated as deep as the mid crust (10-15 km) and that CO2 is an appreciable part of the exsolved vapor. Such is the case in both basaltic and some silicic magmas. Under most conditions, the presence of a CO2-bearing vapor does not hinder, and in fact may promote, the ascent and eruption of the host magma. Carbonic fluids are poorly miscible with aqueous fluids, particularly at high temperature and low pressure, so that the presence of CO2 can induce immiscibility both within the magmatic volatile phase and in hydrothermal systems

  15. Magma Transport from Deep to Shallow Crust and Eruption

    Science.gov (United States)

    White, R. S.; Greenfield, T. S.; Green, R. G.; Brandsdottir, B.; Hudson, T.; Woods, J.; Donaldson, C.; Ágústsdóttir, T.

    2016-12-01

    We have mapped magma transport paths from the deep (20 km) to the shallow (6 km) crust and in two cases to eventual surface eruption under several Icelandic volcanoes (Askja, Bardarbunga, Eyjafjallajokull, Upptyppingar). We use microearthquakes caused by brittle fracture to map magma on the move and tomographic seismic studies of velocity perturbations beneath volcanoes to map the magma storage regions. High-frequency brittle failure earthquakes with magnitudes of typically 0-2 occur where melt is forcing its way through the country rock, or where previously frozen melt is repeatedly re-broken in conduits and dykes. The Icelandic crust on the rift zones where these earthquakes occur is ductile at depths greater than 7 km beneath the surface, so the occurrence of brittle failure seismicity at depths as great as 20 km is indicative of high strain rates, for which magma movement is the most likely explanation. We suggest that high volatile pressures caused by the exsolution of carbon dioxide in the deep crust is driving the magma movement and seismicity at depths of 15-20 km. Eruptions from shallow crustal storage areas are likewise driven by volatile exsolution, though additional volatiles, and in particular water are also involved in the shallow crust.

  16. QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment: NuSOnG

    International Nuclear Information System (INIS)

    Adams, T.; Batra, P.; Bugel, Leonard G.; Camilleri, Leslie Loris; Conrad, Janet Marie; Fisher, Peter H.; Formaggio, Joseph Angelo; Karagiorgi, Georgia S.; )

    2009-01-01

    We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDFs). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parameterized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of 'Beyond the Standard Model' physics

  17. The role of magma mixing/mingling and cumulate melting in the Neapolitan Yellow Tuff caldera-forming eruption (Campi Flegrei, Southern Italy)

    Science.gov (United States)

    Forni, Francesca; Petricca, Eleonora; Bachmann, Olivier; Mollo, Silvio; De Astis, Gianfilippo; Piochi, Monica

    2018-06-01

    Understanding the mechanisms responsible for the generation of chemical gradients in high-volume ignimbrites is key to retrieve information on the processes that control the maturation and eruption of large silicic magmatic reservoirs. Over the last 60 ky, two large ignimbrites showing remarkable zoning were emplaced during caldera-forming eruptions at Campi Flegrei (i.e., Campanian Ignimbrite, CI, 39 ka and Neapolitan Yellow Tuff, NYT, 15 ka). While the CI displays linear compositional, thermal and crystallinity gradients, the NYT is a more complex ignimbrite characterized by crystal-poor magmas ranging in composition from trachy-andesites to phonolites. By combining major and trace element compositions of matrix glasses and mineral phases from juvenile clasts located at different stratigraphic heights along the NYT pyroclastic sequence, we interpret such compositional gradients as the result of mixing/mingling between three different magmas: (1) a resident evolved magma showing geochemical characteristics of a melt extracted from a cumulate mush dominated by clinopyroxene, plagioclase and oxides with minor sanidine and biotite; (2) a hotter and more mafic magma from recharge providing high-An plagioclase and high-Mg clinopyroxene crystals and (3) a compositionally intermediate magma derived from remelting of low temperature mineral phases (i.e., sanidine and biotite) within the cumulate crystal mush. We suggest that the presence of a refractory crystal mush, as documented by the occurrence of abundant crystal clots containing clinopyroxene, plagioclase and oxides, is the main reason for the lack of erupted crystal-rich material in the NYT. A comparison between the NYT and the CI, characterized by both crystal-poor extracted melts and crystal-rich magmas representing remobilized portions of a "mature" (i.e., sanidine dominated) cumulate residue, allows evaluation of the capability of crystal mushes of becoming eruptible upon recharge.

  18. Magma storage in a strike-slip caldera.

    Science.gov (United States)

    Saxby, J; Gottsmann, J; Cashman, K; Gutiérrez, E

    2016-07-22

    Silicic calderas form during explosive volcanic eruptions when magma withdrawal triggers collapse along bounding faults. The nature of specific interactions between magmatism and tectonism in caldera-forming systems is, however, unclear. Regional stress patterns may control the location and geometry of magma reservoirs, which in turn may control the spatial and temporal development of faults. Here we provide new insight into strike-slip volcano-tectonic relations by analysing Bouguer gravity data from Ilopango caldera, El Salvador, which has a long history of catastrophic explosive eruptions. The observed low gravity beneath the caldera is aligned along the principal horizontal stress orientations of the El Salvador Fault Zone. Data inversion shows that the causative low-density structure extends to ca. 6 km depth, which we interpret as a shallow plumbing system comprising a fractured hydrothermal reservoir overlying a magmatic reservoir with vol% exsolved vapour. Fault-controlled localization of magma constrains potential vent locations for future eruptions.

  19. What can Fe stable isotopes tell us about magmas?

    DEFF Research Database (Denmark)

    Stausberg, Niklas

    the differentiation of magmas from the perspective of Fe stable isotopes, integrated with petrology, by studying igneous rocks and their constituent phases (minerals and glasses) from the Bushveld Complex, South Africa, Thingmuli, Iceland, Pantelleria, Italy, and the Bishop Tuff, USA. The findings are interpreted......The majority of the Earth’s crust is formed by magmas, and understanding their production and differentiation is important to interpret the geologic rock record. A powerful tool to investigate magmatic processes is the distribution of the stable isotopes of the major redox-sensitive element...... in magmas, Fe. Fe isotope compositions of magmatic rocks exhibit systematic differences, where the heaviest compositions are found in rhyolites and granites. Understanding of these systematics is complicated by a lack of constraints on Fe isotope fractionation among minerals and liquids under magmatic...

  20. The magma ocean as an impediment to lunar plate tectonics

    Science.gov (United States)

    Warren, Paul H.

    1993-01-01

    The primary impediment to plate tectonics on the moon was probably the great thickness of its crust and particularly its high crust/lithosphere thickness ratio. This in turn can be attributed to the preponderance of low-density feldspar over all other Al-compatible phases in the lunar interior. During the magma ocean epoch, the moon's crust/lithosphere thickness ratio was at the maximum theoretical value, approximately 1, and it remained high for a long time afterwards. A few large regions of thin crust were produced by basin-scale cratering approximately contemporaneous with the demise of the magma ocean. However, these regions probably also tend to have uncommonly thin lithosphere, since they were directly heated and indirectly enriched in K, Th, and U by the same cratering process. Thus, plate tectonics on the moon in the form of systematic lithosphere subduction was impeded by the magma ocean.

  1. Phenomena associated with magma expansion into a drift

    International Nuclear Information System (INIS)

    Gaffney, E.S.

    2002-01-01

    One of the significant threats to the proposed Yucca Mountain nuclear waste repository has been identified as the possibility of intersection of the underground structure by a basaltic intrusion. Based on the geology of the region, it is assumed that such an intrusion would consist of an alkali basalt similar to the nearby Lathrop Wells cone, which has been dated at about 78 ka. The threat of radioactive release may be either from eruption through the surface above the repository of basalt that had been contaminated or from migration through ground water of radionucleides released as a result of damage to waste packages that interact with the magma. As part of our study of these threats, we are analyzing the phenomena associated with magma expansion into drifts in tuff. The early phenomena of the encounter of volatile-rich basaltic magma with a drift are discussed here.

  2. Complexities in Shallow Magma Transport at Kilauea (Invited)

    Science.gov (United States)

    Swanson, D. A.

    2013-12-01

    The standard model of Kilauea's shallow plumbing system includes magma storage under the caldera and conduits in the southwest rift zone (SWRZ) and the east rift zone (ERZ). As a field geologist, I find that seemingly aberrant locations and trends of some eruptive vents indicate complexities in shallow magma transport not addressed by the standard model. This model is not wrong but instead incomplete, because it does not account for the development of offshoots from the main plumbing. These offshoots supply magma to the surface at places that tell us much about the complicated stress system within the volcano. Perhaps most readily grasped are fissures peripheral to the north and south sides of the caldera. Somehow magma can apparently be injected into caldera-bounding faults from the summit reservoir complex, but the process and pathways are unclear. Of more importance is the presence of fissures with ENE trends on the east side of the caldera, including Kilauea Iki. Is this a rift zone that forms an acute angle with the ERZ? I think there is another explanation: the main part of the ERZ has migrated ~5 km SSE during the past few tens of thousands of years owing to seaward movement of the south flank, but older parts of the rift zone can be reactivated. The fissures east of the caldera have the ERZ trend and may record such reactivation; this interpretation includes the location of the largest eruption (15th century) known from Kilauea. Whether or not this interpretation has validity, the question remains: what changes in the plumbing system allow magma to erupt east of the caldera? The SWRZ can be divided into two sections, the SWRZ proper and the seismically active part (SASWRZ) southeast of the SWRZ. The total width of both sections is ~4 km. The SWRZ might be migrating SSE, as is the ERZ. Fissures in the SWRZ proper trend SW. Fissures in the SASWRZ, however, have ENE trends like that of the ERZ, although, because of en echelon offsets, the fissure zone itself

  3. Iron Redox Systematics of Shergottites and Martian Magmas

    Science.gov (United States)

    Righter, Kevin; Danielson, L. R.; Martin, A. M.; Newville, M.; Choi, Y.

    2010-01-01

    Martian meteorites record a range of oxygen fugacities from near the IW buffer to above FMQ buffer [1]. In terrestrial magmas, Fe(3+)/ SigmaFe for this fO2 range are between 0 and 0.25 [2]. Such variation will affect the stability of oxides, pyroxenes, and how the melt equilibrates with volatile species. An understanding of the variation of Fe(3+)/SigmaFe for martian magmas is lacking, and previous work has been on FeO-poor and Al2O3-rich terrestrial basalts. We have initiated a study of the iron redox systematics of martian magmas to better understand FeO and Fe2O3 stability, the stability of magnetite, and the low Ca/high Ca pyroxene [3] ratios observed at the surface.

  4. Molybdenite saturation in silicic magmas: Occurrence and petrological implications

    Science.gov (United States)

    Audetat, A.; Dolejs, D.; Lowenstern, J. B.

    2011-01-01

    We identified molybdenite (MoS2) as an accessory magmatic phase in 13 out of 27 felsic magma systems examined worldwide. The molybdenite occurs as small (molybdenite-saturated samples reveal 1-13 ppm Mo in the melt and geochemical signatures that imply a strong link to continental rift basalt-rhyolite associations. In contrast, arc-associated rhyolites are rarely molybdenite-saturated, despite similar Mo concentrations. This systematic dependence on tectonic setting seems to reflect the higher oxidation state of arc magmas compared with within-plate magmas. A thermodynamic model devised to investigate the effects of T, f O2 and f S2 on molybdenite solubility reliably predicts measured Mo concentrations in molybdenite-saturated samples if the magmas are assumed to have been saturated also in pyrrhotite. Whereas pyrrhotite microphenocrysts have been observed in some of these samples, they have not been observed from other molybdenite-bearing magmas. Based on the strong influence of f S2 on molybdenite solubility we calculate that also these latter magmas must have been at (or very close to) pyrrhotite saturation. In this case the Mo concentration of molybdenite-saturated melts can be used to constrain both magmatic f O2 and f S2 if temperature is known independently (e.g. by zircon saturation thermometry). Our model thus permits evaluation of magmatic f S2, which is an important variable but is difficult to estimate otherwise, particularly in slowly cooled rocks. ?? The Author 2011. Published by Oxford University Press. All rights reserved.

  5. Failed magmatic eruptions: Late-stage cessation of magma ascent

    Science.gov (United States)

    Moran, S.C.; Newhall, C.; Roman, D.C.

    2011-01-01

    When a volcano becomes restless, a primary question is whether the unrest will lead to an eruption. Here we recognize four possible outcomes of a magmatic intrusion: "deep intrusion", "shallow intrusion", "sluggish/viscous magmatic eruption", and "rapid, often explosive magmatic eruption". We define "failed eruptions" as instances in which magma reaches but does not pass the "shallow intrusion" stage, i. e., when magma gets close to, but does not reach, the surface. Competing factors act to promote or hinder the eventual eruption of a magma intrusion. Fresh intrusion from depth, high magma gas content, rapid ascent rates that leave little time for enroute degassing, opening of pathways, and sudden decompression near the surface all act to promote eruption, whereas decreased magma supply from depth, slow ascent, significant enroute degassing and associated increases in viscosity, and impingement on structural barriers all act to hinder eruption. All of these factors interact in complex ways with variable results, but often cause magma to stall at some depth before reaching the surface. Although certain precursory phenomena, such as rapidly escalating seismic swarms or rates of degassing or deformation, are good indicators that an eruption is likely, such phenomena have also been observed in association with intrusions that have ultimately failed to erupt. A perpetual difficulty with quantifying the probability of eruption is a lack of data, particularly on instances of failed eruptions. This difficulty is being addressed in part through the WOVOdat database. Papers in this volume will be an additional resource for scientists grappling with the issue of whether or not an episode of unrest will lead to a magmatic eruption.

  6. Bonding of xenon to oxygen in magmas at depth

    Science.gov (United States)

    Leroy, Clémence; Sanloup, Chrystèle; Bureau, Hélène; Schmidt, Burkhard C.; Konôpková, Zuzana; Raepsaet, Caroline

    2018-02-01

    The field of noble gases chemistry has witnessed amazing advances in the last decade with over 100 compounds reported including Xe oxides and Xe-Fe alloys stable at the pressure-temperature conditions of planetary interiors. The chemistry of Xe with planetary materials is nonetheless still mostly ignored, while Xe isotopes are used to trace a variety of key planetary processes from atmosphere formation to underground nuclear tests. It is indeed difficult to incorporate the possibility of Xe reactivity at depth in isotopic geochemical models without a precise knowledge of its chemical environment. The structure of Xe doped hydrous silica-rich melts is investigated by in situ high energy synchrotron X-ray diffraction using resistive heating diamond anvil cells. Obtained pair distribution functions reveal the oxidation of Xe between 0.2 GPa and 4 GPa at high T up to 1000 K. In addition to the usual interatomic distances, a contribution at 2.05 ± 0.05 Å is observed. This contribution is not observed in the undoped melt, and is interpreted as the Xe-O bond, with a coordination number of about 12 consistent with Xe insertion in rings of the melt structure. Xe solubility measurements by electron microprobe and particle induced X-rays emission analysis confirm that Xe and Ar have similar solubility values in wt% in silicate melts. These values are nonetheless an order of magnitude higher than those theoretically calculated for Xe. The formation of Xe-O bonds explains the enhanced solubility of Xe in deep continental crust magmas, revealing a mechanism that could store Xe and fractionate its isotopes. Xenon is indeed atypical among noble gases, the atmosphere being notably depleted in elemental Xe, and very strongly depleted in Xe light isotopes. These observations are known as the 'missing' Xe paradox, and could be solved by the present findings.

  7. Orientation of the eruption fissures controlled by a shallow magma chamber in Miyakejima

    Directory of Open Access Journals (Sweden)

    Nobuo Geshi

    2016-11-01

    Full Text Available Orientation of the eruption fissures and composition of the lavas of the Miyakejima volcano indicate tectonic influence of a shallow magma chamber on the distribution of eruption fissures. We examined the distributions and magmatic compositions of 23 fissures that formed within the last 2800 years, based on a field survey and a new dataset of 14C ages. The dominant orientation of the eruption fissures in the central portion of the volcano was found to be NE-SW, which is perpendicular to the direction of regional maximum horizontal compressive stress (σHmax. Magmas that show evidences of magma mixing between basaltic and andesitic magmas erupted mainly from the eruption fissures with a higher offset angle from the regional σHmax direction. The presence of a shallow dike-shaped magma chamber controls the distribution of the eruption fissures. The injection of basaltic magma into the shallow andesitic magma chamber caused the temporal rise of internal magmatic pressure in the shallow magma chamber. Dikes extending from the andesitic magma chamber intrude along the local compressive stress field which is generated by the internal excess pressure of the andesitic magma chamber. As the result, the eruption fissures trend parallel to the elongation direction of the shallow magma chamber. Injection of basaltic magma into the shallow andesitic magma chamber caused the magma mixing. Some basaltic dikes from the deep-seated magma chamber reach the ground surface without intersection with the andesitic magma chamber. The patterns of the eruption fissures can be modified in the future as was observed in the case of the destruction of the shallow magma chamber during the 2000 AD eruption.

  8. Cannibalism in a size-structured population: energy extraction and control

    NARCIS (Netherlands)

    Persson, L.; Claessen, D.; de Roos, A.M.; Byström, P.; Sjögren, S.; Svanbäck, R.; Wahlström, E.; Westman, E.

    2004-01-01

    Recent size-structured cannibalistic models point to the importance of the energy gain by cannibals and also show that this gain may result in the emergence of giant individuals. We use a combination of a 10-year field study of a perch (Perca fluviatilis) population and quantitative within-season

  9. Energy extraction from ocean currents using straight bladed cross-flow hydrokinetic turbine

    Directory of Open Access Journals (Sweden)

    Prasad Dudhgaonkar

    2017-04-01

    Full Text Available Harvesting marine renewable energy remains to be a prime focus of researchers across the globe both in environmental and in commercial perspectives. India is blessed with a long coastline, and the seas around Indian peninsula offer ample potential to tap various ocean energy forms. National Institute of Ocean Technology carries out research and various ocean energy technologies, out of which harnessing kinetic energy in seawater currents is one. This article presents the open sea trials recently carried out on National Institute of Ocean Technology’s cross-flow hydrokinetic ocean current turbine in South Andaman. The turbine was designed to generate 100 W electricity at 1.2 m/s current speed and was built in-house. The turbine was initially tested in a seawater channel and then was deployed in Macpherson Strait in Andaman. It was fitted below a floating platform designed especially for this purpose, and the performance of the turbine was continuously logged inside an on-board data acquisition system. The trials were successful and in line with computations.

  10. Isotopic evidence for multiple contributions to felsic magma chambers

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Wiebe, R.A.; Krogstad, E.J.

    2007-01-01

    The Gouldsboro Granite forms part of the Coastal Maine Magmatic Province, a region characterized by granitic plutons that are intimately linked temporally and petrogenetically with abundant co-existing mafic magmas. The pluton is complex and preserves a felsic magma chamber underlain...... with identical isotopic compositions to more mafic dikes suggest that closed system fractionation may be occurring in deeper level chambers prior to injection to shallower levels. The granitic portion of the pluton has the highest Nd isotopic composition (eNd=+3.0) of plutons in the region whereas the mafic...

  11. Silicic magma differentiation in ascent conduits. Experimental constraints

    Science.gov (United States)

    Rodríguez, Carmen; Castro, Antonio

    2017-02-01

    Crystallization of water-bearing silicic magmas in a dynamic thermal boundary layer is reproduced experimentally by using the intrinsic thermal gradient of piston-cylinder assemblies. The standard AGV2 andesite under water-undersaturated conditions is set to crystallize in a dynamic thermal gradient of about 35 °C/mm in 10 mm length capsules. In the hotter area of the capsule, the temperature is initially set at 1200 °C and decreases by programmed cooling at two distinct rates of 0.6 and 9.6 °C/h. Experiments are conducted in horizontally arranged assemblies in a piston cylinder apparatus to avoid any effect of gravity settling and compaction of crystals in long duration runs. The results are conclusive about the effect of water-rich fluids that are expelled out the crystal-rich zone (mush), where water saturation is reached by second boiling in the interstitial liquid. Expelled fluids migrate to the magma ahead of the solidification front contributing to a progressive enrichment in the fluxed components SiO2, K2O and H2O. The composition of water-rich fluids is modelled by mass balance using the chemical composition of glasses (quenched melt). The results are the basis for a model of granite magma differentiation in thermally-zoned conduits with application of in-situ crystallization equations. The intriguing textural and compositional features of the typical autoliths, accompanying granodiorite-tonalite batholiths, can be explained following the results of this study, by critical phenomena leading to splitting of an initially homogeneous magma into two magma systems with sharp boundaries. Magma splitting in thermal boundary layers, formed at the margins of ascent conduits, may operate for several km distances during magma transport from deep sources at the lower crust or upper mantle. Accordingly, conduits may work as chromatographic columns contributing to increase the silica content of ascending magmas and, at the same time, leave behind residual mushes that

  12. Imaging magma plumbing beneath Askja volcano, Iceland

    Science.gov (United States)

    Greenfield, Tim; White, Robert S.

    2015-04-01

    Volcanoes during repose periods are not commonly monitored by dense instrumentation networks and so activity during periods of unrest is difficult to put in context. We have operated a dense seismic network of 3-component, broadband instruments around Askja, a large central volcano in the Northern Volcanic Zone, Iceland, since 2006. Askja last erupted in 1961, with a relatively small basaltic lava flow. Since 1975 the central caldera has been subsiding and there has been no indication of volcanic activity. Despite this, Askja has been one of the more seismically active volcanoes in Iceland. The majority of these events are due to an extensive geothermal area within the caldera and tectonically induced earthquakes to the northeast which are not related to the magma plumbing system. More intriguing are the less numerous deeper earthquakes at 12-24km depth, situated in three distinct areas within the volcanic system. These earthquakes often show a frequency content which is lower than the shallower activity, but they still show strong P and S wave arrivals indicative of brittle failure, despite their location being well below the brittle-ductile boundary, which, in Askja is ~7km bsl. These earthquakes indicate the presence of melt moving or degassing at depth while the volcano is not inflating, as only high strain rates or increased pore fluid pressures would cause brittle fracture in what is normally an aseismic region in the ductile zone. The lower frequency content must be the result of a slower source time function as earthquakes which are both high frequency and low frequency come from the same cluster, thereby discounting a highly attenuating lower crust. To image the plumbing system beneath Askja, local and regional earthquakes have been used as sources to solve for the velocity structure beneath the volcano. Travel-time tables were created using a finite difference technique and the residuals were used to solve simultaneously for both the earthquake locations

  13. Effective coupling functions extracted from the scattering experiments with polarized protons at moderate energies

    International Nuclear Information System (INIS)

    Barut, A.O.; Anders, T.B.; Jachmann, W.

    1992-06-01

    The experimental data for the polarization asymmetries of pp-scattering available at the scattering angle θ = 90 deg. and at various moderate energies, as well as at E = 2.4434 GeV and various scattering angles are described by smooth phenomenological coupling functions for scalar, vector, tensor and the ''magnetic moment'' couplings as well as the corresponding parity conserving axial couplings. The analysis shows a predominant role of the ''axial magnetic moment'', the axial scalar, and the axial vector interactions. Moreover, the data contain oscillations of the type sin(qw 0 -π)/(qw 0 -π), where q is the square root of the energy-momentum transfer. The oscillations have amplitudes of 5%, and a constant frequency w o = 2π/0.88 m p . They arise from oscillating modulations up to 25% of the non-axial coupling functions. 8 refs, 21 figs, 4 tabs

  14. Injection of a Phase Modulated Source into the Z-Beamlet Laser for Increased Energy Extraction.

    Energy Technology Data Exchange (ETDEWEB)

    Rambo, Patrick K.; Armstrong, Darrell J.; Schwarz, Jens; Smith, Ian C; Shores, Jonathon; Speas, Christopher; Porter, John L.

    2014-11-01

    The Z-Beamlet laser has been operating at Sandia National Laboratories since 2001 to provide a source of laser-generated x-rays for radiography of events on the Z-Accelerator. Changes in desired operational scope have necessitated the increase in pulse duration and energy available from the laser system. This is enabled via the addition of a phase modulated seed laser as an alternative front-end. The practical aspects of deployment are discussed here.

  15. The benefits of noise and nonlinearity: Extracting energy from random vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Gammaitoni, Luca, E-mail: luca.gammaitoni@pg.infn.it [NiPS Laboratory, Universita di Perugia, I-06100 Perugia (Italy); Neri, Igor; Vocca, Helios [NiPS Laboratory, Universita di Perugia, I-06100 Perugia (Italy)

    2010-10-05

    Nonlinear behavior is the ordinary feature of the vast majority of dynamical systems and noise is commonly present in any finite temperature physical and chemical system. In this article we briefly review the potentially beneficial outcome of the interplay of noise and nonlinearity by addressing the novel field of vibration energy harvesting. The role of nonlinearity in a piezoelectric harvester oscillator dynamics is modeled with nonlinear stochastic differential equation.

  16. A modeling study of tidal energy extraction and the associated impact on tidal circulation in a multi-inlet bay system of Puget Sound

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Taiping; Yang, Zhaoqing

    2017-12-01

    Previous tidal energy projects in Puget Sound have focused on major deep channels such as Admiralty Inlet that have a larger power potential but pose greater technical challenges than minor tidal channels connecting to small sub-basins. This paper focuses on the possibility of extracting energy from minor tidal channels by using a hydrodynamic model to quantify the power potential and the associated impact on tidal circulation. The study site is a multi-inlet bay system connected by two narrow inlets, Agate Pass and Rich Passage, to the Main Basin of Puget Sound. A three-dimensional hydrodynamic model was applied to the study site and calibrated for tidal elevations and currents. We examined three energy extraction scenarios in which turbines were deployed in each of the two passages and concurrently in both. Extracted power rates and associated changes in tidal elevation, current, tidal flux, and residence time were examined. Maximum instantaneous power rates reached 250 kW, 1550 kW, and 1800 kW, respectively, for the three energy extraction scenarios. The model suggests that with the proposed level of energy extraction, the impact on tidal circulation is very small. It is worth investigating the feasibility of harnessing tidal energy from minor tidal channels of Puget Sound.

  17. Crustal contamination and crystal entrapment during polybaric magma evolution at Mt. Somma-Vesuvius volcano, Italy: Geochemical and Sr isotope evidence

    Science.gov (United States)

    Piochi, M.; Ayuso, R.A.; de Vivo, B.; Somma, R.

    2006-01-01

    New major and trace element analyses and Sr-isotope determinations of rocks from Mt. Somma-Vesuvius volcano produced from 25 ky BP to 1944 AD are part of an extensive database documenting the geochemical evolution of this classic region. Volcanic rocks include silica undersaturated, potassic and ultrapotassic lavas and tephras characterized by variable mineralogy and different crystal abundance, as well as by wide ranges of trace element contents and a wide span of initial Sr-isotopic compositions. Both the degree of undersaturation in silica and the crystal content increase through time, being higher in rocks produced after the eruption at 472 AD (Pollena eruption). Compositional variations have been generally thought to reflect contributions from diverse types of mantle and crust. Magma mixing is commonly invoked as a fundamental process affecting the magmas, in addition to crystal fractionation. Our assessment of geochemical and Sr-isotopic data indicates that compositional variability also reflects the influence of crustal contamination during magma evolution during upward migration to shallow crustal levels and/or by entrapment of crystal mush generated during previous magma storage in the crust. Using a variant of the assimilation fractional crystallization model (Energy Conservation-Assimilation Fractional Crystallization; [Spera and Bohrson, 2001. Energy-constrained open-system magmatic processes I: General model and energy-constrained assimilation and fractional crystallization (EC-AFC) formulation. J. Petrol. 999-1018]; [Bohrson, W.A. and Spera, F.J., 2001. Energy-constrained open-system magmatic process II: application of energy-constrained assimilation-fractional crystallization (EC-AFC) model to magmatic systems. J. Petrol. 1019-1041]) we estimated the contributions from the crust and suggest that contamination by carbonate rocks that underlie the volcano (2 km down to 9-10 km) is a fundamental process controlling magma compositions at Mt. Somma

  18. Extracting energy and structure properties of glass-forming liquids from structural relaxation time.

    Science.gov (United States)

    Wang, Lianwen

    2012-04-18

    A comprehensive examination of the kinetic liquid model (Wang et al 2010 J. Phys.: Condens. Matter 22 455104) is carried out by fitting the structural relaxation time of 26 different glass-forming liquids in a wide temperature range, including most of the well-studied materials. Careful analysis of the compiled reported data reveals that experimental inaccuracies should not be overlooked in any 'benchmark test' of relating theories or models (e.g. in Lunkenheimer et al 2010 Phys. Rev. E 81 051504). The procedure, accuracy, ability, and efficiency of the kinetic liquid model are discussed in detail and in comparison with other available fitting methods. In general, the kinetic liquid model could be verified by 17 of the 26 compiled data sets and can serve as a meaningful approximative method for analyzing these liquids. Nonetheless, further experimental examinations in a wide temperature range are needed and are called for. Through fitting, the microscopic details of these liquids are extracted, namely, the enthalpy, entropy, and cooperativity in structural relaxation, which may facilitate further quantitative analysis to both the liquidus and glassy states of these materials.

  19. Fast GPU-based spot extraction for energy-dispersive X-ray Laue diffraction

    International Nuclear Information System (INIS)

    Alghabi, F.; Schipper, U.; Kolb, A.; Send, S.; Abboud, A.; Pashniak, N.; Pietsch, U.

    2014-01-01

    This paper describes a novel method for fast online analysis of X-ray Laue spots taken by means of an energy-dispersive X-ray 2D detector. Current pnCCD detectors typically operate at some 100 Hz (up to a maximum of 400 Hz) and have a resolution of 384 × 384 pixels, future devices head for even higher pixel counts and frame rates. The proposed online data analysis is based on a computer utilizing multiple Graphics Processing Units (GPUs), which allow for fast and parallel data processing. Our multi-GPU based algorithm is compliant with the rules of stream-based data processing, for which GPUs are optimized. The paper's main contribution is therefore an alternative algorithm for the determination of spot positions and energies over the full sequence of pnCCD data frames. Furthermore, an improved background suppression algorithm is presented.The resulting system is able to process data at the maximum acquisition rate of 400 Hz. We present a detailed analysis of the spot positions and energies deduced from a prior (single-core) CPU-based and the novel GPU-based data processing, showing that the parallel computed results using the GPU implementation are at least of the same quality as prior CPU-based results. Furthermore, the GPU-based algorithm is able to speed up the data processing by a factor of 7 (in comparison to single-core CPU-based algorithm) which effectively makes the detector system more suitable for online data processing

  20. Feedstock specific environmental risk levels related to biomass extraction for energy from boreal and temperate forests

    International Nuclear Information System (INIS)

    Lamers, Patrick; Thiffault, Evelyne; Paré, David; Junginger, Martin

    2013-01-01

    Past research on identifying potentially negative impacts of forest management activities has primarily focused on traditional forest operations. The increased use of forest biomass for energy in recent years, spurred predominantly by policy incentives for the reduction of fossil fuel use and greenhouse gas emissions, and by efforts from the forestry sector to diversify products and increase value from the forests, has again brought much attention to this issue. The implications of such practices continue to be controversially debated; predominantly the adverse impacts on soil productivity and biodiversity, and the climate change mitigation potential of forest bioenergy. Current decision making processes require comprehensive, differentiated assessments of the known and unknown factors and risk levels of potentially adverse environmental effects. This paper provides such an analysis and differentiates between the feedstock of harvesting residues, roundwood, and salvage wood. It concludes that the risks related to biomass for energy outtake are feedstock specific and vary in terms of scientific certainty. Short-term soil productivity risks are higher for residue removal. There is however little field evidence of negative long-term impacts of biomass removal on productivity in the scale predicted by modeling. Risks regarding an alteration of biodiversity are relatively equally distributed across the feedstocks. The risk of limited or absent short-term carbon benefits is highest for roundwood, but negligible for residues and salvage wood. Salvage operation impacts on soil productivity and biodiversity are a key knowledge gap. Future research should also focus on deriving regionally specific, quantitative thresholds for sustainable biomass removal. -- Highlights: ► Synthesis of the scientific uncertainties regarding biomass for energy outtake. ► With specific focus on soil productivity, biodiversity, and carbon balance. ► Balanced determination of the risk levels

  1. A note on extracting electronic stopping from energy spectra of backscattered slow ions applying Bragg's rule

    Science.gov (United States)

    Bruckner, B.; Roth, D.; Goebl, D.; Bauer, P.; Primetzhofer, D.

    2018-05-01

    Electronic stopping measurements in chemically reactive targets, e.g., transition and rare earth metals are challenging. These metals often contain low Z impurities, which contribute to electronic stopping. In this article, we present two ways how one can correct for the presence of impurities in the evaluation of proton and He stopping in Ni for primary energies between 1 and 100 keV, either considering or ignoring the contribution of the low Z impurities to multiple scattering. We find, that for protons either method leads to concordant results, but for heavier projectiles, e.g. He ions, the influence on multiple scattering must not be neglected.

  2. Tapping the earth's geothermal resources: Hydrothermal today, magma tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Kukacka, L.E.

    1986-12-17

    The paper discusses geothermal resources, what it is, where it is, and how to extract energy from it. The materials research activities at Brookhaven National Laboratory related to geothermal energy extraction are discussed. These include high-temperature, light-weight polymer cements, elastomers, biochemical waste processing techniques, and non-metallic heat exchanger tubing. The economics of geothermal energy is also discussed. (ACR)

  3. Energy extraction and water treatment in one system: The idea of using a desalination battery in a cooling tower

    Science.gov (United States)

    Shapira, Barak; Cohen, Izaak; Penki, Tirupathi Rao; Avraham, Eran; Aurbach, Doron

    2018-02-01

    The use of sodium manganese oxide as an intercalation electrode for water treatment was recently explored, and referred to as a "desalination battery" and "hybrid capacitive deionization". Here, we examine the feasibility of using such a desalination battery, comprising crystalline Na4Mn9O18 as the cathode and Ag/AgCl/Cl- electrode as the anode, to extract energy from low-grade waste heat sources. Sodium manganese oxide electrode's material was produced via a solid-state synthesis. Electrodes were produced by spray-coated onto graphite foils, and showed a temperature dependence of the electrode potential, namely, ∂ E / ∂ T , of -0.63 mV/K (whereas, the Ag/AgCl/Cl- mesh electrode showed much lower temperature dependence, < 0.1 mV/K). In order to demonstrate ion-removal capabilities together with the feasibility of thermal-energy conversion, a flow battery system was constructed. Thermally regenerative electrochemical cycles (TREC) were constructed for the flow battery cell. The thermal energy conversion, in this particular system, was shown to be feasible at relatively low C-rate (C/19) with temperatures varying between 30 °C and 70 °C.

  4. Thermally-assisted Magma Emplacement Explains Restless Calderas.

    Science.gov (United States)

    Amoruso, Antonella; Crescentini, Luca; D'Antonio, Massimo; Acocella, Valerio

    2017-08-11

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.

  5. Automatic Compound Annotation from Mass Spectrometry Data Using MAGMa.

    NARCIS (Netherlands)

    Ridder, L.O.; Hooft, van der J.J.J.; Verhoeven, S.

    2014-01-01

    The MAGMa software for automatic annotation of mass spectrometry based fragmentation data was applied to 16 MS/MS datasets of the CASMI 2013 contest. Eight solutions were submitted in category 1 (molecular formula assignments) and twelve in category 2 (molecular structure assignment). The MS/MS

  6. Crystallization of Magma. CEGS Programs Publication Number 14.

    Science.gov (United States)

    Berry, R. W.

    Crystallization of Magma is one of a series of single-topic problem modules intended for use in undergraduate geology and earth science courses. Through problems and observations based on two sets of experiments, this module leads to an understanding of how an igneous rock can form from molten material. Environmental factors responsible for…

  7. Loki Patera as the Surface of a Magma Sea

    Science.gov (United States)

    Matson, D. L.; Davies, A. G.; Veeder, G. J.; Rathbun, J. A.; Johnson, T. V.

    2004-01-01

    Inspired by the finding of Schubert et al that Io's figure is consistent with a hydrostatic shape, we explore the consequences of modeling Loki Patera as the surface of a large magma sea. This model is attractive because of its sheer simplicity and its usefulness in interpreting and predicting observations. Here, we report on that work.

  8. Shallow magma diversions during explosive diatreme-forming eruptions.

    Science.gov (United States)

    Le Corvec, Nicolas; Muirhead, James D; White, James D L

    2018-04-13

    The diversion of magma is an important mechanism that may lead to the relocation of a volcanic vent. Magma diversion is known to occur during explosive volcanic eruptions generating subterranean excavation and remobilization of country and volcanic rocks. However, feedbacks between explosive crater formation and intrusion processes have not been considered previously, despite their importance for understanding evolving hazards during volcanic eruptions. Here, we apply numerical modeling to test the impacts of excavation and subsequent infilling of diatreme structures on stress states and intrusion geometries during the formation of maar-diatreme complexes. Explosive excavation and infilling of diatremes affects local stress states which inhibits magma ascent and drives lateral diversion at various depths, which are expected to promote intra-diatreme explosions, host rock mixing, and vent migration. Our models demonstrate novel mechanisms explaining the generation of saucer-shaped sills, linked with magma diversion and enhanced intra-diatreme explosive fragmentation during maar-diatreme volcanism. Similar mechanisms will occur at other volcanic vents producing crater-forming eruptions.

  9. Design of a Closed-Loop, Bidirectional Brain Machine Interface System With Energy Efficient Neural Feature Extraction and PID Control.

    Science.gov (United States)

    Liu, Xilin; Zhang, Milin; Richardson, Andrew G; Lucas, Timothy H; Van der Spiegel, Jan

    2017-08-01

    This paper presents a bidirectional brain machine interface (BMI) microsystem designed for closed-loop neuroscience research, especially experiments in freely behaving animals. The system-on-chip (SoC) consists of 16-channel neural recording front-ends, neural feature extraction units, 16-channel programmable neural stimulator back-ends, in-channel programmable closed-loop controllers, global analog-digital converters (ADC), and peripheral circuits. The proposed neural feature extraction units includes 1) an ultra low-power neural energy extraction unit enabling a 64-step natural logarithmic domain frequency tuning, and 2) a current-mode action potential (AP) detection unit with time-amplitude window discriminator. A programmable proportional-integral-derivative (PID) controller has been integrated in each channel enabling a various of closed-loop operations. The implemented ADCs include a 10-bit voltage-mode successive approximation register (SAR) ADC for the digitization of the neural feature outputs and/or local field potential (LFP) outputs, and an 8-bit current-mode SAR ADC for the digitization of the action potential outputs. The multi-mode stimulator can be programmed to perform monopolar or bipolar, symmetrical or asymmetrical charge balanced stimulation with a maximum current of 4 mA in an arbitrary channel configuration. The chip has been fabricated in 0.18 μ m CMOS technology, occupying a silicon area of 3.7 mm 2 . The chip dissipates 56 μW/ch on average. General purpose low-power microcontroller with Bluetooth module are integrated in the system to provide wireless link and SoC configuration. Methods, circuit techniques and system topology proposed in this work can be used in a wide range of relevant neurophysiology research, especially closed-loop BMI experiments.

  10. 75 FR 28778 - Magma Flood Retarding Structure (FRS) Supplemental Watershed Plan, Pinal County, AZ

    Science.gov (United States)

    2010-05-24

    ... DEPARTMENT OF AGRICULTURE Natural Resources Conservation Service Magma Flood Retarding Structure... statement is not being prepared for the Magma Flood Retarding Structure (FRS) Supplemental Watershed Plan... rehabilitate the Magma FRS to provide for continued flood protection for a portion of the Town of Florence and...

  11. Extensive, water-rich magma reservoir beneath southern Montserrat

    Science.gov (United States)

    Edmonds, M.; Kohn, S. C.; Hauri, E. H.; Humphreys, M. C. S.; Cassidy, M.

    2016-05-01

    South Soufrière Hills and Soufrière Hills volcanoes are 2 km apart at the southern end of the island of Montserrat, West Indies. Their magmas are distinct geochemically, despite these volcanoes having been active contemporaneously at 131-129 ka. We use the water content of pyroxenes and melt inclusion data to reconstruct the bulk water contents of magmas and their depth of storage prior to eruption. Pyroxenes contain up to 281 ppm H2O, with significant variability between crystals and from core to rim in individual crystals. The Al content of the enstatites from Soufrière Hills Volcano (SHV) is used to constrain melt-pyroxene partitioning for H2O. The SHV enstatite cores record melt water contents of 6-9 wt%. Pyroxene and melt inclusion water concentration pairs from South Soufriere Hills basalts independently constrain pyroxene-melt partitioning of water and produces a comparable range in melt water concentrations. Melt inclusions recorded in plagioclase and in pyroxene contain up to 6.3 wt% H2O. When combined with realistic melt CO2 contents, the depth of magma storage for both volcanoes ranges from 5 to 16 km. The data are consistent with a vertically protracted crystal mush in the upper crust beneath the southern part of Montserrat which contains heterogeneous bodies of eruptible magma. The high water contents of the magmas suggest that they contain a high proportion of exsolved fluids, which has implications for the rheology of the mush and timescales for mush reorganisation prior to eruption. A depletion in water in the outer 50-100 μm of a subset of pyroxenes from pumices from a Vulcanian explosion at Soufrière Hills in 2003 is consistent with diffusive loss of hydrogen during magma ascent over 5-13 h. These timescales are similar to the mean time periods between explosions in 1997 and in 2003, raising the possibility that the driving force for this repetitive explosive behaviour lies not in the shallow system, but in the deeper parts of a vertically

  12. Co-extraction of soluble and insoluble sugars from energy sorghum based on a hydrothermal hydrolysis process.

    Science.gov (United States)

    Yu, Qiang; Tan, Xuesong; Zhuang, Xinshu; Wang, Qiong; Wang, Wen; Qi, Wei; Zhou, Guixiong; Luo, Yu; Yuan, Zhenhong

    2016-12-01

    A process for co-extraction of soluble and insoluble sugars from energy sorghum (ES) was developed based on hydrothermal hydrolysis (HH). Two series of ES were investigated: one (N) with a high biomass yield displayed a higher recalcitrance to sugar release, whereas the second (T) series was characterized by high sugar extraction. The highest total xylose recoveries of 87.2% and 98.7% were obtained for N-11 and T-106 under hydrolysis conditions of 180°C for 50min and 180°C for 30min, respectively. Moreover, the T series displayed higher enzymatic digestibility (ED) than the N series. The high degree of branching (arabinose/xylose ratio) and acetyl groups in the hemicellulose chains of T-106 would be expected to accelerate sugar release during the HH process. In addition, negative correlations between ED and the lignin content, crystallinity index (CrI) and syringyl/guaiacyl (S/G) lignin ratio were observed. Furthermore, finding ways to overcome the thickness of the cell wall and heterogeneity of its chemical composition distribution would make cellulose more accessible to the enzyme. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. A simple fracture energy prediction method for fiber network based on its morphological features extracted by X-ray tomography

    International Nuclear Information System (INIS)

    Huang, Xiang; Wang, Qinghui; Zhou, Wei; Li, Jingrong

    2013-01-01

    The fracture behavior of a novel porous metal fiber sintered sheet (PMFSS) was predicted using a semi-empirical method combining the knowledge of its morphological characteristics and micro-mechanical responses. The morphological characteristics were systematically summarized based on the analysis of the topologically identical skeleton representation extracted from the X-ray tomography images. The analytical model firstly proposed by Tan et al. [1] was further modified according to the experimental observations from both tensile tests of single fibers and sintered fiber sheets, which built the coupling of single fiber segment and fiber network in terms of fracture energy using a simple prediction method. The efficacy of the prediction model was verified by comparing the predicted results to the experimental measurements. The prediction error that arose at high porosity was analyzed through fiber orientation distribution. Moreover, the tensile fracture process evolving from single fiber segments at micro-scale to the global mechanical performance was investigated

  14. Mean excitation energy of polystyrene extracted from proton-stopping-power measurements

    International Nuclear Information System (INIS)

    Porter, L.E.

    1980-01-01

    The measured stopping power of polystyrene for 2.2- to 5.9-MeV protons has been analyzed with the Bloch projectile-z 4 correction term and a modified low-velocity projectile-z 3 term included in the Bethe-Bloch formula. When the full-strength Walske K-shell correction was utilized, the mean excitation energy corresponding to the best fit of the measurements was (71.1 +- 1.8) eV. This result was obtained for a value of the free parameter of the low-velocity projectile-z 3 effect formalism of 1.90 +- 0.05, whether or not a Walske L-shell correction was included

  15. Compact self-powered synchronous energy extraction circuit design with enhanced performance

    Science.gov (United States)

    Liu, Weiqun; Zhao, Caiyou; Badel, Adrien; Formosa, Fabien; Zhu, Qiao; Hu, Guangdi

    2018-04-01

    Synchronous switching circuit is viewed as an effective solution of enhancing the generator’s performance and providing better adaptability for load variations. A critical issue for these synchronous switching circuits is the self-powered realization. In contrast with other methods, the electronic breaker possesses the advantage of simplicity and reliability. However, beside the energy consumption of the electronic breakers, the parasitic capacitance decreases the available piezoelectric voltage. In this technical note, a new compact design of the self-powered switching circuit using electronic breaker is proposed. The envelope diodes are excluded and only a single envelope capacitor is used. The parasitic capacitance is reduced to half with boosted performance while the components are reduced with cost saved.

  16. Energy consumption and greenhouse gas emissions in the recovery and extraction of crude bitumen from Canada’s oil sands

    International Nuclear Information System (INIS)

    Nimana, Balwinder; Canter, Christina; Kumar, Amit

    2015-01-01

    Highlights: • A model to estimate energy consumption and GHG emissions in oil sands is presented. • The model is developed from fundamental engineering principles. • Cogeneration in the oil sands has the ability to offset GHG emissions. • The effect of key parameters is investigated through a sensitivity analysis. - Abstract: A model – FUNNEL-GHG-OS (FUNdamental ENgineering PrinciplEs-based ModeL for Estimation of GreenHouse Gases in the Oil Sands) was developed to estimate project-specific energy consumption and greenhouse gas emissions (GHGs) in major recovery and extraction processes in the oil sands, namely surface mining and in situ production. This model estimates consumption of diesel (4.4–7.1 MJ/GJ of bitumen), natural gas (52.7–86.4 MJ/GJ of bitumen) and electricity (1.8–2.1 kW h/GJ of bitumen) as fuels in surface mining. The model also estimates the consumption of natural gas (123–462.7 MJ/GJ of bitumen) and electricity (1.2–3.5 kW h/GJ of bitumen) in steam assisted gravity drainage (SAGD), based on fundamental engineering principles. Cogeneration in the oil sands, with excess electricity exported to Alberta’s grid, was also explored. Natural gas consumption forms a major portion of the total energy consumption in surface mining and SAGD and thus is a main contributor to GHG emissions. Emissions in surface mining and SAGD range from 4.4 to 7.4 gCO 2 eq/MJ of bitumen and 8.0 to 34.0 gCO 2 eq/MJ of bitumen, respectively, representing a wide range of variability in oil sands projects. Depending upon the cogeneration technology and the efficiency of the process, emissions in oil sands recovery and extraction can be reduced by 16–25% in surface mining and 33–48% in SAGD. Further, a sensitivity analysis was performed to determine the effects of key parameters on the GHG emissions in surface mining and SAGD. Temperature and the consumption of warm water in surface mining and the steam-to-oil ratio (SOR) in SAGD are major parameters

  17. Magma Reservoirs Feeding Giant Radiating Dike Swarms: Insights from Venus

    Science.gov (United States)

    Grosfils, E. B.; Ernst, R. E.

    2003-01-01

    Evidence of lateral dike propagation from shallow magma reservoirs is quite common on the terrestrial planets, and examination of the giant radiating dike swarm population on Venus continues to provide new insight into the way these complex magmatic systems form and evolve. For example, it is becoming clear that many swarms are an amalgamation of multiple discrete phases of dike intrusion. This is not surprising in and of itself, as on Earth there is clear evidence that formation of both magma reservoirs and individual giant radiating dikes often involves periodic magma injection. Similarly, giant radiating swarms on Earth can contain temporally discrete subswarms defined on the basis of geometry, crosscutting relationships, and geochemical or paleomagnetic signatures. The Venus data are important, however, because erosion, sedimentation, plate tectonic disruption, etc. on Earth have destroyed most giant radiating dike swarm's source regions, and thus we remain uncertain about the geometry and temporal evolution of the magma sources from which the dikes are fed. Are the reservoirs which feed the dikes large or small, and what are the implications for how the dikes themselves form? Does each subswarm originate from a single, periodically reactivated reservoir, or do subswarms emerge from multiple discrete geographic foci? If the latter, are these discrete foci located at the margins of a single large magma body, or do multiple smaller reservoirs define the character of the magmatic center as a whole? Similarly, does the locus of magmatic activity change with time, or are all the foci active simultaneously? Careful study of giant radiating dike swarms on Venus is yielding the data necessary to address these questions and constrain future modeling efforts. Here, using giant radiating dike swarms from the Nemesis Tessera (V14) and Carson (V43) quadrangles as examples, we illustrate some of the dike swarm focal region diversity observed on Venus and briefly explore some

  18. Seismic tremors and magma wagging during explosive volcanism.

    Science.gov (United States)

    Jellinek, A Mark; Bercovici, David

    2011-02-24

    Volcanic tremor is a ubiquitous feature of explosive eruptions. This oscillation persists for minutes to weeks and is characterized by a remarkably narrow band of frequencies from about 0.5 Hz to 7 Hz (refs 1-4). Before major eruptions, tremor can occur in concert with increased gas flux and related ground deformation. Volcanic tremor is thus of particular value for eruption forecasting. Most models for volcanic tremor rely on specific properties of the geometry, structure and constitution of volcanic conduits as well as the gas content of the erupting magma. Because neither the initial structure nor the evolution of the magma-conduit system will be the same from one volcano to the next, it is surprising that tremor characteristics are so consistent among different volcanoes. Indeed, this universality of tremor properties remains a major enigma. Here we employ the contemporary view that silicic magma rises in the conduit as a columnar plug surrounded by a highly vesicular annulus of sheared bubbles. We demonstrate that, for most geologically relevant conditions, the magma column will oscillate or 'wag' against the restoring 'gas-spring' force of the annulus at observed tremor frequencies. In contrast to previous models, the magma-wagging oscillation is relatively insensitive to the conduit structure and geometry, which explains the narrow band of tremor frequencies observed around the world. Moreover, the model predicts that as an eruption proceeds there will be an upward drift in both the maximum frequency and the total signal frequency bandwidth, the nature of which depends on the explosivity of the eruption, as is often observed.

  19. Mezcla de magmas en Vulcanello (Isla Vulcano, Italia

    Directory of Open Access Journals (Sweden)

    Aparicio, A.

    2008-06-01

    Full Text Available Volcanic activity in Vulcano starts about 350 ka ago and continues up to present day with the development of thre main episodes corresponding to the calderas of Piano and La Fossa, and Vulcanello. These cover a compositional range from rhyolitic to trachybasaltic rocks. This lithological diversity is produced by different petrogenetic processes such as fractional crystallization, assimilation coupled to fractional crystallization (AFC, mixing, etc.The eruption of Vulcanello area emitted trachyandesitic materials, including shoshonites and latites. A magma-mixing process is established between trachytes and shoshonites to origine latites. Trachytes and rhyolites are produced by fractional crystallization and by ACF processes (assimilation of sedimentary rocks from trachyandesitic magmas.La actividad volcánica de Isla Vulcano comienzó aproximadamente hace 350.000 años y continúa hasta la actualidad con el desarrollo de tres grandes episodios correspondientes a las caldera de Piano, caldera de Fossa y a Vulcanello, que han emitido piroclastos y coladas de composiciones muy variadas, desde riolitas a traquibasaltos. Esta variedad litológica ha sido relacionada con procesos petrogenéticos tan diversos como cristalización fraccionada, asimilación simultánea con cristalización (ACF, mezcla de magmas, etc.El episodio de Vulcanello emite rocas traquiandesíticas, con composiciones shoshoníticas y latíticas. Un proceso de mezcla de magmas es reconocido entre traquitas y shoshonitas para generar latitas. Traquitas y riolitas son producidas por procesos de cristalización fraccionada simple y por ACF con asimilación de rocas sedimentarias a partir de magmas traquiandesíticos.

  20. Feasibility of Geothermal Energy Extraction from Non-Activated Petroleum Wells in Arun Field

    Science.gov (United States)

    Syarifudin, M.; Octavius, F.; Maurice, K.

    2016-09-01

    The big obstacle to develop geothermal is frequently came from the economical viewpoint which mostly contributed by the drilling cost. However, it potentially be tackled by converting the existing decommissioned petroleum well to be converted for geothermal purposes. In Arun Field, Aceh, there are 188 wells and 62% of them are inactive (2013). The major obstacle is that the outlet water temperature from this conversion setup will not as high as the temperature that come out from the conventional geothermal well, since it will only range from 60 to 180oC depending on several key parameters such as the values of ground temperature, geothermal gradient in current location, the flow inside of the tubes, and type of the tubes (the effect from these parameters are studied). It will just be considered as low to medium temperature, according to geothermal well classification. Several adjustments has to be made such as putting out pipes inside the well that have been used to lift the oil/gas and replacing them with a curly long coil tubing which act as a heat exchanger. It will convert the cold water from the surface to be indirectly heated by the hot rock at the bottom of the well in a closed loop system. In order to make power production, the binary cycle system is used so that the low to medium temperature fluid is able to generate electricity. Based on this study, producing geothermal energy for direct use and electricity generation in Arun Field is technically possible. In this study case, we conclude that 2900 kW of electricity could be generated. While for-direct utility, a lot of local industries in Northern Sumatera could get the benefits from this innovation.

  1. Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 1. Intereruption deformation, 1997–2008

    Science.gov (United States)

    Lu, Zhong; Dzurisin, Daniel; Biggs, Juliet; Wicks, Charles; McNutt, Steve

    2010-01-01

    Starting soon after the 1997 eruption at Okmok volcano and continuing until the start of the 2008 eruption, magma accumulated in a storage zone centered ~3.5 km beneath the caldera floor at a rate that varied with time. A Mogi-type point pressure source or finite sphere with a radius of 1 km provides an adequate fit to the deformation field portrayed in time-sequential interferometric synthetic aperture radar images. From the end of the 1997 eruption through summer 2004, magma storage increased by 3.2–4.5 × 107 m3, which corresponds to 75–85% of the magma volume erupted in 1997. Thereafter, the average magma supply rate decreased such that by 10 July 2008, 2 days before the start of the 2008 eruption, magma storage had increased by 3.7–5.2 × 107 m3 or 85–100% of the 1997 eruption volume. We propose that the supply rate decreased in response to the diminishing pressure gradient between the shallow storage zone and a deeper magma source region. Eventually the effects of continuing magma supply and vesiculation of stored magma caused a critical pressure threshold to be exceeded, triggering the 2008 eruption. A similar pattern of initially rapid inflation followed by oscillatory but generally slowing inflation was observed prior to the 1997 eruption. In both cases, withdrawal of magma during the eruptions depressurized the shallow storage zone, causing significant volcano-wide subsidence and initiating a new intereruption deformation cycle.

  2. Pressure effect on Fe3+/FeT in silicate melts and applications to magma redox, particularly in magma oceans

    Science.gov (United States)

    Zhang, H.; Hirschmann, M. M.

    2014-12-01

    The proportions of Fe3+ and Fe2+ in magmas reflect the redox conditions of their origin and influence the chemical and physical properties of natural silicate liquids, but the relationship between Fe3+/FeT and oxygen fugacity depends on pressure owing to different molar volumes and compressibilities of Fe3+ and Fe2+ in silicates. An important case where the effect of pressure effect may be important is in magma oceans, where well mixed (and therefore potentially uniform Fe3+/FeT) experiencses a wide range of pressures, and therefore can impart different ƒO2 at different depths, influencing magma ocean degassing and early atmospheres, as well as chemical gradients within magma oceans. To investigate the effect of pressure on magmatic Fe3+/FeT we conducted high pressure expeirments on ƒO2-buffered andestic liquids. Quenched glasses were analyzed by Mössbauer spectroscopy. To verify the accuracy of Mössbauer determinations of Fe3+/FeT in glasses, we also conducted low temperature Mössbauer studies to determine differences in the recoilless fraction (ƒ) of Fe2+ and Fe3. These indicate that room temperature Mössbauer determinations of on Fe3+/FeT glasses are systematically high by 4% compared to recoilless-fraction corrected ratios. Up to 7 GPa, pressure decreases Fe3+/FeT, at fixed ƒO2 relative to metal-oxide buffers, meaning that an isochemical magma will become more reduced with decreasing pressure. Consequently, for small planetary bodies such as the Moon or Mercury, atmospheres overlying their MO will be highly reducing, consisting chiefly of H2 and CO. The same may also be true for Mars. The trend may reverse at higher pressure, as is the case for solid peridotite, and so for Earth, Venus, and possibly Mars, more oxidized atmospheres above MO are possible. Diamond anvil experiments are underway to examine this hypothesis.

  3. The expected greenhouse benefits from developing magma power at Long Valley, California

    International Nuclear Information System (INIS)

    Haraden, John.

    1995-01-01

    Magma power is the production of electricity from shallow magma bodies. Before magma becomes a practical source of power, many engineering problems must still be solved. When they are solved, the most likely site for the first magma power plant is Long Valley, California, USA. In this paper, we examine the greenhouse benefits from developing Long Valley. By generating magma power and by curtailing an equal amount of fossil power, we estimate the expected mass and the expected discounted value of reduced CO 2 emissions. For both measures, the expected benefits seem to be substantial. (author)

  4. Proof-of-Concept of a Zinc-Silver Battery for the Extraction of Energy from a Concentration Difference

    Directory of Open Access Journals (Sweden)

    Massimo Marino

    2014-06-01

    Full Text Available The conversion of heat into current can be obtained by a process with two stages. In the first one, the heat is used for distilling a solution and obtaining two flows with different concentrations. In the second stage, the two flows are sent to an electrochemical cell that produces current by consuming the concentration difference. In this paper, we propose such an electrochemical cell, working with water solutions of zinc chloride. The cell contains two electrodes, made respectively of zinc and silver covered by silver chloride. The operation of the cell is analogous to that of the capacitive mixing and of the “mixing entropy battery”: the electrodes are charged while dipped in the concentrated solution and discharged when dipped in the diluted solution. The cyclic operation allows us to extract a surplus of energy, at the expense of the free energy of the concentration difference. We evaluate the feasibility of such a cell for practical applications and find that a power up to 2 W per m2 of the surface of the electrodes can be achieved.

  5. Extracting Aggregation Free Energies of Mixed Clusters from Simulations of Small Systems: Application to Ionic Surfactant Micelles.

    Science.gov (United States)

    Zhang, X; Patel, L A; Beckwith, O; Schneider, R; Weeden, C J; Kindt, J T

    2017-11-14

    Micelle cluster distributions from molecular dynamics simulations of a solvent-free coarse-grained model of sodium octyl sulfate (SOS) were analyzed using an improved method to extract equilibrium association constants from small-system simulations containing one or two micelle clusters at equilibrium with free surfactants and counterions. The statistical-thermodynamic and mathematical foundations of this partition-enabled analysis of cluster histograms (PEACH) approach are presented. A dramatic reduction in computational time for analysis was achieved through a strategy similar to the selector variable method to circumvent the need for exhaustive enumeration of the possible partitions of surfactants and counterions into clusters. Using statistics from a set of small-system (up to 60 SOS molecules) simulations as input, equilibrium association constants for micelle clusters were obtained as a function of both number of surfactants and number of associated counterions through a global fitting procedure. The resulting free energies were able to accurately predict micelle size and charge distributions in a large (560 molecule) system. The evolution of micelle size and charge with SOS concentration as predicted by the PEACH-derived free energies and by a phenomenological four-parameter model fit, along with the sensitivity of these predictions to variations in cluster definitions, are analyzed and discussed.

  6. Acute effects of a herb extract formulation and inulin fibre on appetite, energy intake and food choice.

    Science.gov (United States)

    Harrold, J A; Hughes, G M; O'Shiel, K; Quinn, E; Boyland, E J; Williams, N J; Halford, J C G

    2013-03-01

    The impact of two commercially available products, a patented herb extract Yerbe Maté, Guarana and Damiana (YGD) formulation and an inulin-based soluble fermentable fibre (SFF), alone or in combination, on appetite and food intake were studied for the first time in a double blind, placebo-controlled, cross-over design. 58 normal to slightly overweight women consumed a fixed-load breakfast followed 4h later by an ad libitum lunch. They were administered YGD (3 tablets) and SFF (5g in 100ml water), YGD and water (100ml), SFF and placebo (3 tablets) or water and placebo 15min before meals. Appetite was assessed using visual analogue scales, and energy intake was measured at lunch. Significant reductions in food intake and energy intake were observed when YGD was present (59.5g, 16.3%; 112.4kcal, 17.3%) and when SFF was present (31.9g, 9.1%; 80kcal, 11.7%) compared with conditions were products were absent. The lowest intake (gram and kcal) was in the YGD+SFF condition. Significant reductions in AUC hunger and AUC desire to eat were also observed after YGD+SFF combination. The data demonstrate that YGD produces a robust short-term effect on caloric intake, an effect augmented by SFF. Caloric compensation for SFF indicates independent effects on appetite regulation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Seasonal Evaporation and Surface Energy Budget Estimation Across an Arid Agricultural Region in Saudi Arabia: Quantifying Groundwater Extraction

    Science.gov (United States)

    Aragon, B.; Huang, D.; Houborg, R.; Dasari, H. P.; Hoteit, I.; McCabe, M.

    2017-12-01

    In arid-land agricultural environments, knowledge of the water and energy budget is critical in order to sustainably manage the allocation and use of water resources. Using long-term weather reanalysis data from the Weather Research and Forecasting (WRF) model and a time-series record of Landsat 8 imagery, we apply the Priestly-Taylor Jet Propulsion Lab (PT-JPL) model to estimate the energy budget over the Al Jawf agricultural region in the north of Saudi Arabia. This zone generates a significant proportion of the agricultural production in Saudi Arabia and consumes an important fraction of the non-renewable water resources. This research contributes towards efforts seeking to quantify the precise amount of water that is used in agriculture - a difficult variable given that the overwhelming majority of supply comes from groundwater extraction. Results of this research can be used to improve crop management and to mitigate aquifer over-exploitation by monitoring the indiscriminate use of water and establishing bounds around the rates of groundwater withdrawal.

  8. Duration of a Magma Ocean and Subsequent Mantle Overturn in Mars: Evidence from Nakhlites

    Science.gov (United States)

    Debaille, V.; Brandon, A. D.; Yin, Q.-Z.; Jacobsen, B.

    2008-01-01

    It is now generally accepted that the heat produced by accretion, short-lived radioactive elements such as Al-26, and gravitational energy from core formation was sufficient to at least partially melt the silicate portions of terrestrial planets resulting in a global-scale magma ocean. More particularly, in Mars, the geochemical signatures displayed by shergottites, are likely inherited from the crystallization of this magma ocean. Using the short-lived chronometer Sm-146 - Nd-142 (t(sup 1/2) = 103 Myr), the duration of the Martian magma ocean (MMO) has been evaluated to being less than 40 Myr, while recent and more precise ND-142/ND-144 data were used to evaluate the longevity of the MMO to approximately 100 Myr after the solar system formation. In addition, it has been proposed that the end of the crystallization of the MMO may have triggered a mantle overturn, as a result of a density gradient in the cumulate layers crystallized at different levels. Dating the mantle overturn could hence provide additional constraint on the duration of the MMO. Among SNC meteorites, nakhlites are characterized by high epsilon W-182 of approximately +3 and an epsilon Nd-142 similar to depleted shergottites of +0.6-0.9. It has hence been proposed that the source of nakhlites was established very early in Mars history (approximately 8-10 Myr). However, the times recorded in HF-182-W-182 isotope system, i.e. when 182Hf became effectively extinct (approximately 50 Myr after solar system formation) are less than closure times recorded in the Sm-146-Nd-142 isotope system (with a full coverage of approximately 500 Myr after solar system formation). This could result in decoupling between the present-day measured epsilon W-182 and epsilon Nd-142 as the SM-146 may have recorded later differentiation events in epsilon ND-142 not observed in epsilon W-182 values. With these potential complexities in short-lived chronological data for SNC's in mind, new Hf-176/Hf-177, Nd-143/Nd-144 and Nd

  9. Determination of the cosmological parameters and the nature of dark energy; Extraction des parametres cosmologiques et des proprietes de l'energie noire

    Energy Technology Data Exchange (ETDEWEB)

    Linden, S.

    2010-04-15

    The measured properties of the dark energy component being consistent with a Cosmological Constant, {Lambda}, this cosmological standard model is referred to as the {Lambda}-Cold-Dark-Matter ({Lambda}CDM) model. Despite its overall success, this model suffers from various problems. The existence of a Cosmological Constant raises fundamental questions. Attempts to describe it as the energy contribution from the vacuum as following from Quantum Field Theory failed quantitatively. In consequence, a large number of alternative models have been developed to describe the dark energy component: modified gravity, additional dimensions, Quintessence models. Also, astrophysical effects have been considered to mimic an accelerated expansion. The basics of the {Lambda}CDM model and the various attempts of explaining dark energy are outlined in this thesis. Another major problem of the model comes from the dependencies of the fit results on a number of a priori assumptions and parameterization effects. Today, combined analyses of the various cosmological probes are performed to extract the parameters of the model. Due to a wrong model assumption or a bad parameterization of the real physics, one might end up measuring with high precision something which is not there. We show, that indeed due to the high precision of modern cosmological measurements, purely kinematic approaches to distance measurements no longer yield valid fit results except for accidental special cases, and that a fit of the exact (integral) redshift-distance relation is necessary. The main results of this work concern the use of the CPL parameterization of dark energy when coping with the dynamics of tracker solutions of Quintessence models, and the risk of introducing biases on the parameters due to the possibly prohibited extrapolation to arbitrary high redshifts of the SN type Ia magnitude calibration relation, which is obtained in the low-redshift regime. Whereas the risks of applying CPL shows up to be

  10. Tube pumices as strain markers of the ductile-brittle transition during magma fragmentation

    Science.gov (United States)

    Martí, J.; Soriano, C.; Dingwell, D. B.

    1999-12-01

    Magma fragmentation-the process by which relatively slow-moving magma transforms into a violent gas flow carrying fragments of magma-is the defining feature of explosive volcanism. Yet of all the processes involved in explosively erupting systems, fragmentation is possibly the least understood. Several theoretical and laboratory studies on magma degassing and fragmentation have produced a general picture of the sequence of events leading to the fragmentation of silicic magma. But there remains a debate over whether magma fragmentation is a consequence of the textural evolution of magma to a foamed state where disintegration of walls separating bubbles becomes inevitable due to a foam-collapse criterion, or whether magma is fragmented purely by stresses that exceed its tensile strength. Here we show that tube pumice-where extreme bubble elongation is observed-is a well-preserved magmatic `strain marker' of the stress state immediately before and during fragmentation. Structural elements in the pumice record the evolution of the magma's mechanical response from viscous behaviour (foaming and foam elongation) through the plastic or viscoelastic stage, and finally to brittle behaviour. These observations directly support the hypothesis that fragmentation occurs when magma undergoes a ductile-brittle transition and stresses exceed the magma's tensile strength.

  11. Terrestrial magma ocean and core segregation in the earth

    Science.gov (United States)

    Ohtani, Eiji; Yurimoto, Naoyoshi

    1992-01-01

    According to the recent theories of formation of the earth, the outer layer of the proto-earth was molten and the terrestrial magma ocean was formed when its radius exceeded 3000 km. Core formation should have started in this magma ocean stage, since segregation of metallic iron occurs effectively by melting of the proto-earth. Therefore, interactions between magma, mantle minerals, and metallic iron in the magma ocean stage controlled the geochemistry of the mantle and core. We have studied the partitioning behaviors of elements into the silicate melt, high pressure minerals, and metallic iron under the deep upper mantle and lower mantle conditions. We employed the multi-anvil apparatus for preparing the equilibrating samples in the ranges from 16 to 27 GPa and 1700-2400 C. Both the electron probe microanalyzer (EPMA) and the Secondary Ion Mass spectrometer (SIMS) were used for analyzing the run products. We obtained the partition coefficients of various trace elements between majorite, Mg-perovskite, and liquid, and magnesiowustite, Mg-perovskite, and metallic iron. The examples of the partition coefficients of some key elements are summarized in figures, together with the previous data. We may be able to assess the origin of the mantle abundances of the elements such as transition metals by using the partitioning data obtained above. The mantle abundances of some transition metals expected by the core-mantle equilibrium under the lower mantle conditions cannot explain the observed abundance of some elements such as Mn and Ge in the mantle. Estimations of the densities of the ultrabasic magma Mg-perovskite at high pressure suggest existence of a density crossover in the deep lower mantle; flotation of Mg-perovskite occurs in the deep magma ocean under the lower mantle conditions. The observed depletion of some transition metals such as V, Cr, Mn, Fe, Co, and Ni in the mantle may be explained by the two stage process, the core-mantle equilibrium under the lower

  12. Depths of Magma Chambers in the Icelandic Crust

    Science.gov (United States)

    Kelley, D. F.; Kapostasy, D. D.; Barton, M.

    2004-05-01

    There is considerable interest in the structure and thermal state of the crust in Iceland, which lies across the Mid Atlantic Ridge. However, interpretations of seismic and gravity data yield conflicting views of the nature of the lower crust. Some interpretations prefer a model in which the lower crust (15-25 km) is relatively cool and solid, whereas other interpretations, based largely on gravity data, prefer a model in which the lower crust is relatively warm and possibly partially molten. Knowledge of the depth of magma chambers is critical to constrain the geothermal gradient in Icelandic crust and to resolve discrepancies in interpretation of geophysical data. Analyses of aphyric lavas and of glasses in Icelandic lavas erupted from 11 volcanic centers have been compiled. The compositions are picritic and basaltic with SiO2 - 47 to 50 wt%, MgO - 6 to 15wt%, FeO - 8 to 14wt%, to, Na2O - 1.3 to 3.3 wt%, and K2O - 0.03-46 wt%. The pressures of equilibration of these liquids with ol, high-Ca pyx and plag were estimated qualitatively from projections into the pseudoternary system Ol-Di-Silica using methods described by Walker and coworkers and Grove and coworkers. The results (ca. 0.5 GPa) indicate crystallization in magma chambers located at about 16 km depth. Equilibration pressures were also calculated using the method described by Yang and coworkers and by a modified version of this method. Calculated pressures (0.45±0.15 GPa) indicate magma chambers located at 15±4 km depth. Equilibration pressures for Rekjanes Ridge glasses determined using the same techniques are 0.2±0.1 GPa, corresponding to depths of 7.6±3 km. The results indicate the presence of magma chambers in the deep Icelandic crust and that the latter is relatively warm. Shallower chambers (3-7 km) have been identified from seismic studies suggesting a complex magma plumbing system. The results also confirm that magma chambers beneath Iceland are located at greater depths than those beneath the

  13. When Magma Meets Carbonate: Explosive Criminals of Climate Change?

    Science.gov (United States)

    Carter, L. B.

    2017-12-01

    The natural carbon cycle is a key component of global climate change. Identifying and quantifying all processes in the cycle is essential to determine the effects of human greenhouse gas contributions and make future predictions. Volcanoes are the main natural source of carbon dioxide to the atmosphere [1]. In settings where carbonate rocks underlie the edifice, they can be consumed by magma passing through, which can release extra CO2, potentially explaining the extremely high emissions at Mount Etna in Italy [2-4]. We conduct laboratory experiments, mimicking conditions in the crust, to study how different carbonate rocks interact with hot magmas at pressure, and determine the amount of CO2 generated. We find that some types of magma can raise volcanic gas output and cause more explosive and dangerous eruptions [5-6]. Others are more likely to release hot fluids to the surrounding rocks, releasing CO2 by skarnification, which leaves economically important ores like in the western US [3,7] but can weaken the subsurface, potentially leading to landslides. Gas can also be released on the flanks of a volcano or in regions lacking an active volcano, due to the breakdown of certain carbonate rocks by heat [7], seen as bubbling springs in Yellowstone [8]. Our experiments indicate that if dolostone, not limestone, surrounds a magma chamber, over half the CO2 that was locked in the crust can escape even at lower temperatures a distance away. These processes are perhaps pertinent to why the Earth's climate was warm >50 million years ago, when more magma-carbonate interaction likely occurred than today [3] and thus contributed several times the current volcanic output [4] to the atmosphere. As significant parts of the long-term carbon cycle, it is necessary to include magma-carbonate reactions when considering climate changes before taking into account human input. [1] Aiuppa et al 2017 ESciRev (168) 24-47; [2] Ganino and Arndt 2009 Geol (37) 323-326; [3] Lee et al. 2013

  14. Driving magma to the surface: The 2011-2012 El Hierro Volcanic Eruption

    Science.gov (United States)

    López, Carmen; Benito-Saz, Maria A.; Martí, Joan; del-Fresno, Carmen; García-Cañada, Laura; Albert, Helena; Lamolda, Héctor

    2017-08-01

    We reanalyzed the seismic and deformation data corresponding to the preeruptive unrest on El Hierro (Canary Islands) in 2011. We considered new information about the internal structure of the island. We updated the seismic catalog to estimate the full evolution of the released seismic energy and demonstrate the importance of nonlocated earthquakes. Using seismic data and GPS displacements, we characterized the shear-tensile type of the predominant fracturing and modeled the strain and stress fields for different time periods. This enabled us to identify a prolonged first phase characterized by hydraulic tensile fracturing, which we interpret as being related to the emplacement of new magma below the volcanic edifice on El Hierro. This was followed by postinjection unidirectional migration, probably controlled by the stress field and the distribution of the structural discontinuities. We identified the effects of energetic magmatic pulses occurring a few days before the eruption that induced shear seismicity on preexisting faults within the volcano and raised the Coulomb stress over the whole crust. We suggest that these magmatic pulses reflect the crossing of the Moho discontinuity, as well as changes in the path geometry of the dyke migration toward the surface. The final phase involved magma ascent through a prefractured crust.

  15. Degassing during magma ascent in the Mule Creek vent (USA)

    Science.gov (United States)

    Stasiuk, M.V.; Barclay, J.; Carroll, M.R.; Jaupart, Claude; Ratte, J.C.; Sparks, R.S.J.; Tait, S.R.

    1996-01-01

    The structures and textures of the rhyolite in the Mule Creek vent (New Mexico, USA) indicate mechanisms by which volatiles escape from silicic magma during eruption. The vent outcrop is a 300-m-high canyon wall comprising a section through the top of a feeder conduit, vent and the base of an extrusive lava dome. Field relations show that eruption began with an explosive phase and ended with lava extrusion. Analyses of glass inclusions in quartz phenocrysts from the lava indicate that the magma had a pre-eruptive dissolved water content of 2.5-3.0 wt% and, during eruption, the magma would have been water-saturated over the vertical extent of the present outcrop. However, the vesicularity of the rhyolite is substantially lower than that predicted from closed-system models of vesiculation under equilibrium conditions. At a given elevation in the vent, the volume fraction of primary vesicles in the rhyolite increases from zero close to the vent margin to values of 20-40 vol.% in the central part. In the centre the vesicularity increases upward from approximately 20 vol.% at 300 m below the canyon rim to approximately 40 vol.% at 200 m, above which it shows little increase. To account for the discrepancy between observed vesicularity and measured water content, we conclude that gas escaped during ascent, probably beginning at depths greater than exposed, by flow through the vesicular magma. Gas escape was most efficient near the vent margin, and we postulate that this is due both to the slow ascent of magma there, giving the most time for gas to escape, and to shear, favouring bubble coalescence. Such shear-related permeability in erupting magma is supported by the preserved distribution of textures and vesicularity in the rhyolite: Vesicles are flattened and overlapping near the dense margins and become progressively more isolated and less deformed toward the porous centre. Local zones have textures which suggest the coalescence of bubbles to form permeable

  16. Finite automata over magmas: models and some applications in Cryptography

    Directory of Open Access Journals (Sweden)

    Volodymyr V. Skobelev

    2018-05-01

    Full Text Available In the paper the families of finite semi-automata and reversible finite Mealy and Moore automata over finite magmas are defined and analyzed in detail. On the base of these models it is established that the set of finite quasigroups is the most acceptable subset of the set of finite magmas at resolving model problems in Cryptography, such as design of iterated hash functions and stream ciphers. Defined families of finite semi-automata and reversible finite automata over finite $T$-quasigroups are investigated in detail. It is established that in this case models time and space complexity for simulation of the functioning during one instant of automaton time can be much lower than in general case.

  17. A magma ocean and the Earth's internal water budget

    Science.gov (United States)

    Ahrens, Thomas J.

    1992-01-01

    There are lines of evidence which relate bounds on the primordial water content of the Earth's mantle to a magma ocean and the accompanying Earth accretion process. We assume initially (before a magma ocean could form) that as the Earth accreted, it grew from volatile- (H2O, CO2, NH3, CH4, SO2, plus noble) gas-rich planetesimals, which accreted to form an initial 'primitive accretion core' (PAC). The PAC retained the initial complement of planetesimal gaseous components. Shock wave experiments in which both solid, and more recently, the gaseous components of materials such as serpentine and the Murchison meteorite have demonstrated that planetesimal infall velocities of less than 0.5 km/sec, induce shock pressures of less than 0.5 GPa and result in virtually complete retention of planetary gases.

  18. Evidence of a global magma ocean in Io's interior.

    Science.gov (United States)

    Khurana, Krishan K; Jia, Xianzhe; Kivelson, Margaret G; Nimmo, Francis; Schubert, Gerald; Russell, Christopher T

    2011-06-03

    Extensive volcanism and high-temperature lavas hint at a global magma reservoir in Io, but no direct evidence has been available. We exploited Jupiter's rotating magnetic field as a sounding signal and show that the magnetometer data collected by the Galileo spacecraft near Io provide evidence of electromagnetic induction from a global conducting layer. We demonstrate that a completely solid mantle provides insufficient response to explain the magnetometer observations, but a global subsurface magma layer with a thickness of over 50 kilometers and a rock melt fraction of 20% or more is fully consistent with the observations. We also place a stronger upper limit of about 110 nanoteslas (surface equatorial field) on the dynamo dipolar field generated inside Io.

  19. Coal and Oil: The Dark Monarchs of Global Energy: Understanding Supply and Extraction Patterns and their Importance for Future Production

    International Nuclear Information System (INIS)

    Hoeoek, Mikael

    2010-01-01

    The formation of modern society has been dominated by coal and oil, and together these two fossil fuels account for nearly two thirds of all primary energy used by mankind. This makes future production a key question for future social development and this thesis attempts to answer whether it is possible to rely on an assumption of ever increasing production of coal and oil. Both coal and oil are finite resources, created over long time scales by geological processes. It is thus impossible to extract more fossil fuels than geologically available. In other words, there are limits to growth imposed by nature. The concept of depletion and exhaustion of recoverable resources is a fundamental question for the future extraction of coal and oil. Historical experience shows that peaking is a well established phenomenon in production of various natural resources. Coal and oil are no exceptions, and historical data shows that easily exploitable resources are exhausted while more challenging deposits are left for the future. For oil, depletion can also be tied directly to the physical laws governing fluid flows in reservoirs. Understanding and predicting behaviour of individual fields, in particularly giant fields, are essential for understanding future production. Based on comprehensive databases with reserve and production data for hundreds of oilfields, typical patterns were found. Alternatively, depletion can manifest itself indirectly through various mechanisms. This has been studied for coal. Over 60% of the global crude oil production is derived from only around 330 giant oilfields, where many of them are becoming increasingly mature. The annual decline in existing oil production has been determined to be around 6% and it is unrealistic that this will be offset by new field developments, additional discoveries or unconventional oil. This implies that the peak of the oil age is here. For coal a similar picture emerges, where 90% of the global coal production originates

  20. Thermally-assisted Magma Emplacement Explains Restless Calderas

    Science.gov (United States)

    Amoruso, A.; Crescentini, L.; D'Antonio, M.; Acocella, V.

    2017-12-01

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei, Italy, which is the best-known, yet most dangerous calderas, lying to the west of Naples and restless since the 1950s at least.Our elaboration of the geodetic data indicates that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust.Our thermal models show that the repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth 3 ka before the last eruption and, in turn, contributed to maintain the thermal anomaly itself. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks.Available information at other calderas highlights similarities to Campi Flegrei, in the pattern and cause of unrest. All monitored restless calderas have either geodetically (Yellowstone, Aira Iwo-Jima, Askja, Fernandina and, partly, Long Valley) or geophysically (Rabaul, Okmok) detected sill-like intrusions inducing repeated unrest. Some calderas (Yellowstone, Long Valley) also show stable deformation pattern, where inflation insists on and mimics the resurgence uplift. The common existence of sill-like sources, also responsible for stable deformation patterns, in restless calderas suggests close similarities to Campi Flegrei. This suggests a wider applicability of our model of thermally-assisted sill emplacement, to be tested by future studies to better understand not only the dynamics of restless

  1. MAGMA: generalized gene-set analysis of GWAS data.

    Science.gov (United States)

    de Leeuw, Christiaan A; Mooij, Joris M; Heskes, Tom; Posthuma, Danielle

    2015-04-01

    By aggregating data for complex traits in a biologically meaningful way, gene and gene-set analysis constitute a valuable addition to single-marker analysis. However, although various methods for gene and gene-set analysis currently exist, they generally suffer from a number of issues. Statistical power for most methods is strongly affected by linkage disequilibrium between markers, multi-marker associations are often hard to detect, and the reliance on permutation to compute p-values tends to make the analysis computationally very expensive. To address these issues we have developed MAGMA, a novel tool for gene and gene-set analysis. The gene analysis is based on a multiple regression model, to provide better statistical performance. The gene-set analysis is built as a separate layer around the gene analysis for additional flexibility. This gene-set analysis also uses a regression structure to allow generalization to analysis of continuous properties of genes and simultaneous analysis of multiple gene sets and other gene properties. Simulations and an analysis of Crohn's Disease data are used to evaluate the performance of MAGMA and to compare it to a number of other gene and gene-set analysis tools. The results show that MAGMA has significantly more power than other tools for both the gene and the gene-set analysis, identifying more genes and gene sets associated with Crohn's Disease while maintaining a correct type 1 error rate. Moreover, the MAGMA analysis of the Crohn's Disease data was found to be considerably faster as well.

  2. The chlorine isotope fingerprint of the lunar magma ocean.

    Science.gov (United States)

    Boyce, Jeremy W; Treiman, Allan H; Guan, Yunbin; Ma, Chi; Eiler, John M; Gross, Juliane; Greenwood, James P; Stolper, Edward M

    2015-09-01

    The Moon contains chlorine that is isotopically unlike that of any other body yet studied in the Solar System, an observation that has been interpreted to support traditional models of the formation of a nominally hydrogen-free ("dry") Moon. We have analyzed abundances and isotopic compositions of Cl and H in lunar mare basalts, and find little evidence that anhydrous lava outgassing was important in generating chlorine isotope anomalies, because (37)Cl/(35)Cl ratios are not related to Cl abundance, H abundance, or D/H ratios in a manner consistent with the lava-outgassing hypothesis. Instead, (37)Cl/(35)Cl correlates positively with Cl abundance in apatite, as well as with whole-rock Th abundances and La/Lu ratios, suggesting that the high (37)Cl/(35)Cl in lunar basalts is inherited from urKREEP, the last dregs of the lunar magma ocean. These new data suggest that the high chlorine isotope ratios of lunar basalts result not from the degassing of their lavas but from degassing of the lunar magma ocean early in the Moon's history. Chlorine isotope variability is therefore an indicator of planetary magma ocean degassing, an important stage in the formation of terrestrial planets.

  3. Isotopic abundances relevant to the identification of magma sources

    International Nuclear Information System (INIS)

    O'Nions, R.K.

    1984-01-01

    The behaviour of natural radiogenic isotope tracers in the Earth that have lithophile and atmophile geochemical affinity is reviewed. The isotope tracer signature of oceanic and continental crust may in favourable circumstances by sufficiently distinct from that of the mantle to render a contribution from these sources resolvable within the isotopic composition of the magma. Components derived from the sedimentary and altered basaltic portion of oceanic crust are recognized in some island arc magmas from their Sr, Nd and Pb isotopic signatures. The rare-gas isotope tracers (He, Ar, Xe in particular) are not readily recycled into the mantle and thus provide the basis of an approach that is complementary to that based on the lithophile tracers. In particular, a small mantle-derived helium component may be readily recognized in the presence of a predominant radiogenic component generated in the continents. The importance of assessing the mass balance of these interactions rather than merely a qualitative recognition is emphasized. The question of the relative, contribution of continental-oceanic crust and mantle to magma sources is an essential part of the problem of generation and evolution of continental crust. An approach to this problem through consideration of the isotopic composition of sediments is briefly discussed. (author)

  4. Parental magmas of Mare Fecunditatis - Evidence from pristine glasses

    International Nuclear Information System (INIS)

    Jin, Y.; Taylor, L.A.

    1990-01-01

    Results are presented on the petrography and electron microprobe analyses of 14 discrete glass beads from the Luna 16 core sample (21036,15) from Mare Fecunditatis regolith, that were previously characterized as representing pristine glasses. Compared to Apollo pristine glasses analyzed by Delano (1986), the Luna 16 pristine glasses have higher CaO and Al2O3 contents but lower MgO and Ni. On the basis of their contents of MgO, FeO, Al2O3, and CaO, these pristine glasses could be divided into two groups, A and B. It is suggested that at least two parental magmas are needed to explain the chemical variations among these glasses. The Group B glasses appear to represent primitive parental magma that evolved by olivine fractionation to the compositions of the Luna 16 aluminous mare basalts, whereas the Group A volcanic glasses may represent an unusual new basalt magma type that contains a high plagioclase component. 14 refs

  5. Automatic Compound Annotation from Mass Spectrometry Data Using MAGMa.

    Science.gov (United States)

    Ridder, Lars; van der Hooft, Justin J J; Verhoeven, Stefan

    2014-01-01

    The MAGMa software for automatic annotation of mass spectrometry based fragmentation data was applied to 16 MS/MS datasets of the CASMI 2013 contest. Eight solutions were submitted in category 1 (molecular formula assignments) and twelve in category 2 (molecular structure assignment). The MS/MS peaks of each challenge were matched with in silico generated substructures of candidate molecules from PubChem, resulting in penalty scores that were used for candidate ranking. In 6 of the 12 submitted solutions in category 2, the correct chemical structure obtained the best score, whereas 3 molecules were ranked outside the top 5. All top ranked molecular formulas submitted in category 1 were correct. In addition, we present MAGMa results generated retrospectively for the remaining challenges. Successful application of the MAGMa algorithm required inclusion of the relevant candidate molecules, application of the appropriate mass tolerance and a sufficient degree of in silico fragmentation of the candidate molecules. Furthermore, the effect of the exhaustiveness of the candidate lists and limitations of substructure based scoring are discussed.

  6. Concentration variance decay during magma mixing: a volcanic chronometer.

    Science.gov (United States)

    Perugini, Diego; De Campos, Cristina P; Petrelli, Maurizio; Dingwell, Donald B

    2015-09-21

    The mixing of magmas is a common phenomenon in explosive eruptions. Concentration variance is a useful metric of this process and its decay (CVD) with time is an inevitable consequence during the progress of magma mixing. In order to calibrate this petrological/volcanological clock we have performed a time-series of high temperature experiments of magma mixing. The results of these experiments demonstrate that compositional variance decays exponentially with time. With this calibration the CVD rate (CVD-R) becomes a new geochronometer for the time lapse from initiation of mixing to eruption. The resultant novel technique is fully independent of the typically unknown advective history of mixing - a notorious uncertainty which plagues the application of many diffusional analyses of magmatic history. Using the calibrated CVD-R technique we have obtained mingling-to-eruption times for three explosive volcanic eruptions from Campi Flegrei (Italy) in the range of tens of minutes. These in turn imply ascent velocities of 5-8 meters per second. We anticipate the routine application of the CVD-R geochronometer to the eruptive products of active volcanoes in future in order to constrain typical "mixing to eruption" time lapses such that monitoring activities can be targeted at relevant timescales and signals during volcanic unrest.

  7. Woody biomass: Niche position as a source of sustainable renewable chemicals and energy and kinetics of hot-water extraction/hydrolysis.

    Science.gov (United States)

    Liu, Shijie

    2010-01-01

    The conversion of biomass to chemicals and energy is imperative to sustaining our way of life as known to us today. Fossil chemical and energy sources are traditionally regarded as wastes from a distant past. Petroleum, natural gas, and coal are not being regenerated in a sustainable manner. However, biomass sources such as algae, grasses, bushes and forests are continuously being replenished. Woody biomass represents the most abundant and available biomass source. Woody biomass is a reliably sustainable source of chemicals and energy that could be replenished at a rate consistent with our needs. The biorefinery is a concept describing the collection of processes used to convert biomass to chemicals and energy. Woody biomass presents more challenges than cereal grains for conversion to platform chemicals due to its stereochemical structures. Woody biomass can be thought of as comprised of at least four components: extractives, hemicellulose, lignin and cellulose. Each of these four components has a different degree of resistance to chemical, thermal and biological degradation. The biorefinery concept proposed at ESF (State University of New York - College of Environmental Science and Forestry) aims at incremental sequential deconstruction, fractionation/conversion of woody biomass to achieve efficient separation of major components. The emphasis of this work is on the kinetics of hot-water extraction, filling the gap in the fundamental understanding, linking engineering developments, and completing the first step in the biorefinery processes. This first step removes extractives and hemicellulose fractions from woody biomass. While extractives and hemicellulose are largely removed in the extraction liquor, cellulose and lignin largely remain in the residual woody structure. Xylo-oligomers and acetic acid in the extract are the major components having the greatest potential value for development. Extraction/hydrolysis involves at least 16 general reactions that could

  8. Making mushy magma chambers in the lower continental crust: Cold storage and compositional bimodality

    Science.gov (United States)

    Jackson, Matthew; Blundy, Jon; Sparks, Steve

    2017-04-01

    Increasing geological and geophysical evidence suggests that crustal magma reservoirs are normally low melt fraction 'mushes' rather than high melt fraction 'magma chambers'. Yet high melt fractions must form within these mush reservoirs to explain the observed flow and eruption of low crystallinity magmas. In many models, crystallinity is linked directly to temperature, with higher temperature corresponding to lower crystallinity (higher melt fraction). However, increasing temperature yields less evolved (silicic) melt composition for a given starting material. If mobile, low crystallinity magmas require high temperature, it is difficult to explain how they can have evolved composition. Here we use numerical modelling to show that reactive melt flow in a porous and permeable mush reservoir formed by the intrusion of numerous basaltic sills into the lower continental crust produces magma in high melt fraction (> 0.5) layers akin to conventional magma chambers. These magma-chamber-like layers contain evolved (silicic) melt compositions and form at low (close to solidus) temperatures near the top of the mush reservoir. Evolved magma is therefore kept in 'cold storage' at low temperature, but also at low crystallinity so the magma is mobile and can leave the mush reservoir. Buoyancy-driven reactive flow and accumulation of melt in the mush reservoir controls the temperature and composition of magma that can leave the reservoir. The modelling also shows that processes in lower crustal mush reservoirs produce mobile magmas that contain melt of either silicic or mafic composition. Intermediate melt compositions are present but are not within mobile magmas. Silicic melt compositions are found at high melt fraction within the magma-chamber like layers near the top of the mush reservoir. Mafic melt compositions are found at high melt fraction within the cooling sills. Melt elsewhere in the reservoir has intermediate composition, but remains trapped in the reservoir because

  9. Exploiting the spontaneous potential of the electrodes used in the capacitive mixing technique for the extraction of energy from salinity difference

    NARCIS (Netherlands)

    Brogioli, D.; Ziano, R.; Rica, R.A.; Salerno, D.; Kozynchenko, O.; Hamelers, H.V.M.; Mantegazza, F.

    2012-01-01

    The "capacitive mixing" (CAPMIX) technique is aimed at the extraction of energy from the salinity difference between the sea and rivers. It is based on the voltage rise that takes place at the electrodes when changing the salt concentration of the solution in which the two electrodes are dipped. In

  10. Magma displacements under insular volcanic fields, applications to eruption forecasting: El Hierro, Canary Islands, 2011-2013

    Science.gov (United States)

    García, A.; Fernández-Ros, A.; Berrocoso, M.; Marrero, J. M.; Prates, G.; De la Cruz-Reyna, S.; Ortiz, R.

    2014-04-01

    Significant deformations, followed by increased seismicity detected since 2011 July at El Hierro, Canary Islands, Spain, prompted the deployment of additional monitoring equipment. The climax of this unrest was a submarine eruption first detected on 2011 October 10, and located at about 2 km SW of La Restinga, southernmost village of El Hierro Island. The eruption ceased on 2012 March 5, after the volcanic tremor signals persistently weakened through 2012 February. However, the seismic activity did not end with the eruption, as several other seismic crises followed. The seismic episodes presented a characteristic pattern: over a few days the number and magnitude of seismic event increased persistently, culminating in seismic events severe enough to be felt all over the island. Those crises occurred in 2011 November, 2012 June and September, 2012 December to 2013 January and in 2013 March-April. In all cases the seismic unrest was preceded by significant deformations measured on the island's surface that continued during the whole episode. Analysis of the available GPS and seismic data suggests that several magma displacement processes occurred at depth from the beginning of the unrest. The first main magma movement or `injection' culminated with the 2011 October submarine eruption. A model combining the geometry of the magma injection process and the variations in seismic energy release has allowed successful forecasting of the new-vent opening.

  11. Control of amphibious weed ipomoea (Ipomoea carnea) by utilizing it for the extraction of volatile fatty acids as energy precursors.

    Science.gov (United States)

    Rafiq Kumar, M; Tauseef, S M; Abbasi, Tasneem; Abbasi, S A

    2015-01-01

    Volatile fatty acids (VFAs), comprising mainly of acetic acid and lesser quantities of propionic and butyric acids, are generated when zoomass or phytomass is acted upon by acidogenic and acetogenic microorganisms. VFAs can be utilized by methanogens under anaerobic conditions to generate flammable methane-carbon dioxide mixtures known as 'biogas'. Acting on the premise that this manner of VFA utilization for generating relatively clean energy can be easily accomplished in a controlled fashion in conventional biogas plants as well as higher-rate anaerobic digesters, we have carried out studies aimed to generate VFAs from the pernicious weed ipomoea (Ipomoea carnea). The VFA extraction was accomplished by a simple yet effective technology, appropriate for use even by laypersons. For this acid-phase reactors were set, to which measured quantities of ipomoea leaves were charged along with water inoculated with cow dung. The reactors were stirred intermittently. It was found that VFA production started within hours of the mixing of the reactants and peaked by the 10(th) or 11(th) day in all the reactors, effecting a conversion of over 10% of the biomass into VFAs. The reactor performance had good reproducibility and the process appeared easily controllable, frugal and robust.

  12. Control of amphibious weed ipomoea (Ipomoea carnea by utilizing it for the extraction of volatile fatty acids as energy precursors

    Directory of Open Access Journals (Sweden)

    M. Rafiq Kumar

    2015-01-01

    Full Text Available Volatile fatty acids (VFAs, comprising mainly of acetic acid and lesser quantities of propionic and butyric acids, are generated when zoomass or phytomass is acted upon by acidogenic and acetogenic microorganisms. VFAs can be utilized by methanogens under anaerobic conditions to generate flammable methane–carbon dioxide mixtures known as ‘biogas’. Acting on the premise that this manner of VFA utilization for generating relatively clean energy can be easily accomplished in a controlled fashion in conventional biogas plants as well as higher-rate anaerobic digesters, we have carried out studies aimed to generate VFAs from the pernicious weed ipomoea (Ipomoea carnea. The VFA extraction was accomplished by a simple yet effective technology, appropriate for use even by laypersons. For this acid-phase reactors were set, to which measured quantities of ipomoea leaves were charged along with water inoculated with cow dung. The reactors were stirred intermittently. It was found that VFA production started within hours of the mixing of the reactants and peaked by the 10th or 11th day in all the reactors, effecting a conversion of over 10% of the biomass into VFAs. The reactor performance had good reproducibility and the process appeared easily controllable, frugal and robust.

  13. Oxygen isotope study of the Long Valley magma system, California: isotope thermometry and convection in large silicic magma bodies

    Science.gov (United States)

    Bindeman, Ilya; Valley, John

    2002-07-01

    Products of voluminous pyroclastic eruptions with eruptive draw-down of several kilometers provide a snap-shot view of batholith-scale magma chambers, and quench pre-eruptive isotopic fractionations (i.e., temperatures) between minerals. We report analyses of oxygen isotope ratio in individual quartz phenocrysts and concentrates of magnetite, pyroxene, and zircon from individual pumice clasts of ignimbrite and fall units of caldera-forming 0.76 Ma Bishop Tuff (BT), pre-caldera Glass Mountain (2.1-0.78 Ma), and post-caldera rhyolites (0.65-0.04 Ma) to characterize the long-lived, batholith-scale magma chamber beneath Long Valley Caldera in California. Values of δ18O show a subtle 1‰ decrease from the oldest Glass Mountain lavas to the youngest post-caldera rhyolites. Older Glass Mountain lavas exhibit larger ( 1‰) variability of δ18O(quartz). The youngest domes of Glass Mountain are similar to BT in δ18O(quartz) values and reflect convective homogenization during formation of BT magma chamber surrounded by extremely heterogeneous country rocks (ranging from 2 to +29‰). Oxygen isotope thermometry of BT confirms a temperature gradient between "Late" (815 °C) and "Early" (715 °C) BT. The δ18O(quartz) values of "Early" and "Late" BT are +8.33 and 8.21‰, consistent with a constant δ18O(melt)=7.8+/-0.1‰ and 100 °C temperature difference. Zircon-melt saturation equilibria gives a similar temperature range. Values of δ18O(quartz) for different stratigraphic units of BT, and in pumice clasts ranging in pre-eruptive depths from 6 to 11 km (based on melt inclusions), and document vertical and lateral homogeneity of δ18O(melt). Worldwide, five other large-volume rhyolites, Lava Creek, Lower Bandelier, Fish Canyon, Cerro Galan, and Toba, exhibit equal δ18O(melt) values of earlier and later erupted portions in each of the these climactic caldera-forming eruptions. We interpret the large-scale δ18O homogeneity of BT and other large magma chambers as evidence

  14. Buffered and unbuffered dike emplacement on Earth and Venus - Implications for magma reservoir size, depth, and rate of magma replenishment

    Science.gov (United States)

    Parfitt, E. A.; Head, J. W., III

    1993-01-01

    Models of the emplacement of lateral dikes from magma chambers under constant (buffered) driving pressure conditions and declining (unbuffered) driving pressure conditions indicate that the two pressure scenarios lead to distinctly different styles of dike emplacement. In the unbuffered case, the lengths and widths of laterally emplaced dikes will be severely limited and the dike lengths will be highly dependent on chamber size; this dependence suggests that average dike length can be used to infer the dimensions of the source magma reservoir. On Earth, the characteristics of many mafic-dike swarms suggest that they were emplaced in buffered conditions (e.g., the Mackenzie dike swarm in Canada and some dikes within the Scottish Tertiary). On Venus, the distinctive radial fractures and graben surrounding circular to oval features and edifices on many size scales and extending for hundreds to over a thousand km are candidates for dike emplacement in buffered conditions.

  15. Geochemical evidences of magma dynamics at Campi Flegrei (Italy)

    Science.gov (United States)

    Caliro, S.; Chiodini, G.; Paonita, A.

    2014-05-01

    Campi Flegrei caldera, within the Neapolitan area of Italy, is potentially one of the most dangerous volcanoes in the world, and during the last decade it has shown clear signs of reactivation, marked by the onset of uplift and changes in the geochemistry of gas emissions. We describe a 30-year-long data set of the CO2-He-Ar-N2 compositions of fumarolic emissions from La Solfatara crater, which is located in the center of the caldera. The data display continuous decreases in both the N2/He and N2/CO2 ratios since 1985, paralleled by an increase in He/CO2. These variations cannot be explained by either processes of boiling/condensation in the local hydrothermal system or with changes in the mixing proportions between a magmatic vapor and hydrothermal fluids. We applied the magma degassing model of Nuccio and Paonita (2001, Earth Planet. Sci. Lett. 193, 467-481) using the most recent inert-gas solubilities in order to interpret these peculiar features in accordance with petrologic constraints derived from the ranges of the melt compositions and reservoir pressures at Campi Flegrei. The model simulations for mafic melts (trachybasalt and shoshonite) show a remarkably good agreement with the measured data. Both decompressive degassing of an ascending magma and mixing between magmatic fluids exsolved at various levels along the ascent path can explain the long-term geochemical changes. Recalling that (i) a sill-like reservoir of gases at a depth of 3-4 km seems to be the main source of ground inflation and (ii) there is petrologic and geophysical evidence for a reservoir of magma at about 8 km below Campi Flegrei, we suggest that the most-intense episodes of inflation occur when the gas supply to the sill-like reservoir comes from the 8 km-deep magma, although fluids exsolved by magma bodies at shallower depths also contribute to the gas budget. Our work highlights that, in caldera systems where the presence of hydrothermal aquifers commonly masks the magmatic signature

  16. Computer Simulation To Assess The Feasibility Of Coring Magma

    Science.gov (United States)

    Su, J.; Eichelberger, J. C.

    2017-12-01

    Lava lakes on Kilauea Volcano, Hawaii have been successfully cored many times, often with nearly complete recovery and at temperatures exceeding 1100oC. Water exiting nozzles on the diamond core bit face quenches melt to glass just ahead of the advancing bit. The bit readily cuts a clean annulus and the core, fully quenched lava, passes smoothly into the core barrel. The core remains intact after recovery, even when there are comparable amounts of glass and crystals with different coefficients of thermal expansion. The unique resulting data reveal the rate and sequence of crystal growth in cooling basaltic lava and the continuous liquid line of descent as a function of temperature from basalt to rhyolite. Now that magma bodies, rather than lava pooled at the surface, have been penetrated by geothermal drilling, the question arises as to whether similar coring could be conducted at depth, providing fundamentally new insights into behavior of magma. This situation is considerably more complex because the coring would be conducted at depths exceeding 2 km and drilling fluid pressures of 20 MPa or more. Criteria that must be satisfied include: 1) melt is quenched ahead of the bit and the core itself must be quenched before it enters the barrel; 2) circulating drilling fluid must keep the temperature of the coring assembling cooled to within operational limits; 3) the drilling fluid column must nowhere exceed the local boiling point. A fluid flow simulation was conducted to estimate the process parameters necessary to maintain workable temperatures during the coring operation. SolidWorks Flow Simulation was used to estimate the effect of process parameters on the temperature distribution of the magma immediately surrounding the borehole and of drilling fluid within the bottom-hole assembly (BHA). A solid model of the BHA was created in SolidWorks to capture the flow behavior around the BHA components. Process parameters used in the model include the fluid properties and

  17. Magma Mixing: Magmatic Enclaves in Morne Micotrin, Dominica

    Science.gov (United States)

    Hickernell, S.; Frey, H. M.; Manon, M. R. F.; Waters, L. E.

    2017-12-01

    Magmatic enclaves in volcanic rocks provide direct evidence of magma mingling/mixing within a magma reservoir and may reinvigorate the system and trigger eruption, as documented at the Soufriere Hills in Montserrat. Lava domes on the neighboring island of Dominica also contain multiple enclave populations and may be evidence for similar magma chamber processes. The central dome of Micotrin is at the head of the Roseau Valley, which was filled with 3 km3 of pyroclastic deposits from eruptions spanning 65 - 25 ka. There appear to be two distinct types of enclaves in the crystal-rich Micotrin andesites (60 wt% SiO2), fine-grained and coarse-grained. Fine-grained mafic enclaves (52 wt% SiO2) vary in size from 1 to 15 cm in diameter, whereas the coarse-grained enclaves are generally larger and range from 3-20 cm. Fine-grained enclaves are saturated in plag (35%) + opx (35%) + cpx (20%) + oxides (10%). Average pyroxenes are 0.01 to 0.02 cm in size, whereas plagioclase averages 0.05 cm and up to 0.1 cm. The texture of the fine-grained enclaves is cumulate-like, devoid of microlites and matrix glass. Coarse-grained enclaves lack cpx and have different modal abundances and textures: plag (75%) + opx (10%) + oxides (5%) + plag microlites (10%). Plagioclase are 0.1 cm in size and orthopyroxenes average 0.05 cm. The coarse-grained enclaves are highly vesicular, a notable difference from the host as well as the fine-grained enclaves. The boundaries of both the fine- and coarse-grained enclaves are quite sharp and distinct and there do not appear to be enclave minerals disaggregated in the host rock. Temperatures were determined by two oxides. The fine-grained enclaves had two populations of magnetite, yielding 847 + 21° and 920 + 17°C. The coarse-grained enclave was 890 + 42 °C, but the oxides were extensively exsolved. Plagioclase composition in both coarse and fine-grained samples was comparable, ranging from An50 to An80. Despite compositional similarity the textures of

  18. Magma Mixing: Why Picrites are Not So Hot

    Science.gov (United States)

    Natland, J. H.

    2010-12-01

    Oxide gabbros or ferrogabbros are the late, low-temperature differentiates of tholeiitic magma and usually form as cumulates that can have 2-30% of the magmatic oxides, ilmenite and magnetite. They are common in the ocean crust and are likely ubiquitous wherever extensive tholeiitic magmatism has occurred, especially beneath thick lava piles such as at Hawaii, Iceland, oceanic plateaus, island arcs and ancient continental crust. When intruded by hot primitive magma including picrite, the oxide-bearing portions of these rocks are readily partially melted or assimilated into the magma and contribute to it a degree of iron and titanium enrichment that is not reflective of the mantle source of the primitive magma. The most extreme examples of such mixing are meimechites and ferropicrites, but this type of end-member mixing is even common in MORB. To the extent this process occurs, the eruptive picrite cannot be used to estimate compositions of partial melts of mantle rocks, nor their eruptive or potential temperatures, using olivine-liquid FeO-MgO backtrack procedures. Most picrites have glasses with compositions approximating those expected from low-pressure multiphase cotectic crystallization, and olivine that on average crystallized from liquids of nearly those compositions. The hallmark of such rocks is the presence of minerals other than olivine among phenocrysts (plagioclase at Iceland, clinopyroxene at many oceanic islands), Fe- and Ti-rich chromian spinel (ankaramites, ferropicrites and meimichites), and in some cases the presence of iron-rich olivine (hortonolite ~Fo65 in ferropicrites), Ti-rich kaersutitic amphibole and even apatite (meimechites); the latter two derive from late-stage, hydrous and geochemically enriched metamorphic or alkalic assimilants. This type of mixing, however, does not necessarily involve depleted and enriched mixing components. To avoid such mixing, primitive melts have to rise primarily through upper mantle rocks of near-zero melt

  19. Eruptive dynamics during magma decompression: a laboratory approach

    Science.gov (United States)

    Spina, L.; Cimarelli, C.; Scheu, B.; Wadsworth, F.; Dingwell, D. B.

    2013-12-01

    A variety of eruptive styles characterizes the activity of a given volcano. Indeed, eruptive styles can range from effusive phenomena to explosive eruptions, with related implications for hazard management. Rapid changes in eruptive style can occur during an ongoing eruption. These changes are, amongst other, related to variations in the magma ascent rate, a key parameter affecting the eruptive style. Ascent rate is in turn dependent on several factors such as the pressure in the magma chamber, the physical properties of the magma and the rate at which these properties change. According to the high number of involved parameters, laboratory decompression experiments are the best way to achieve quantitative information on the interplay of each of those factors and the related impact on the eruption style, i.e. by analyzing the flow and deformation behavior of the transparent volatile-bearing analogue fluid. We carried out decompression experiments following different decompression paths and using silicone oil as an analogue for the melt, with which we can simulate a range of melt viscosity values. For a set of experiments we added rigid particles to simulate the presence of crystals in the magma. The pure liquid or suspension was mounted into a transparent autoclave and pressurized to different final pressures. Then the sample was saturated with argon for a fixed amount of time. The decompression path consists of a slow decompression from the initial pressure to the atmospheric condition. Alternatively, samples were decompressed almost instantaneously, after established steps of slow decompression. The decompression path was monitored with pressure transducers and a high-speed video camera. Image analysis of the videos gives quantitative information on the bubble distribution with respect to depth in the liquid, pressure and time of nucleation and on their characteristics and behavior during the ongoing magma ascent. Furthermore, we also monitored the evolution of

  20. Comparative morphophysiological evaluation of the testis of adult Wistar rats fed low protein-energy diet and dosed with aqueous extracts of Cuscuta australis.

    Science.gov (United States)

    Ozegbe, P C; Omirinde, J O

    2012-12-18

    Cuscuta australis (C. australis) seed and stem are historically used by the local population as dietary supplement for the management of infertility. This study, therefore, evaluated the effect of orally administered aqueous extracts of C. australis seed and stem, 300 mg/kg body weight/day for seven days, on the testis of the adult Wistar rat fed either low or normal protein-energy diets. The control group received water. The relative weight of the testis was non-significantly increased (p>0.05) in the Low Protein-energy diet-Water-treated (LPWA), Low Protein-energy diet-Seed-treated (LPSE) and Normal Protein-energy diet-Seed-treated (NPSE) groups relative to the Normal Protein-energy diet-Water-treated (NPWA). The weight of the testis was also non-significantly increased (p˃0.05) in the Low Protein-energy diet-Stem-treated (LPST), but decreased in the Normal Protein-energy diet-Stem-treated (NPST), relative to LPWA and NPWA. Heights of germinal epithelium were significantly decreased (p<0.05) in the LPWA, LPSE and LPST relative to the NPWA, NPSE and NPST. Diet significantly influenced (p<0.001) the effect of stem extract on the height of germinal epithelium. The NPSE, LPSE, NPST, LPST and LPWA showed significantly decreased (p<0.001) plasma levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) relative to NPWA. The LPWA, LPSE and NPST also showed significantly decreased (p<0.001) levels of testosterone relative to NPWA and LPST. Diet significantly influenced (p<0.001) the effect of seed on the level of LH. Seed-diet interactions significantly affected the levels of FSH (p<0.001) and LH (p<0.05), but not testosterone. Diet significantly influenced (p<0.001) the effects of stem extract on the levels of FSH, LH and testosterone. Stem-diet interactions significantly affected (p<0.001) the levels of FSH, LH and testosterone. Our data suggest that the aqueous extract of C. australis stem is more potent than the seed extract and that dietary protein-energy

  1. Extracting the cross section angular distributions for 15C high-energy resonance excited via the (18O,16O two-neutron transfer reaction

    Directory of Open Access Journals (Sweden)

    Carbone D.

    2016-01-01

    Full Text Available The 13C(18O,16O15C reaction has been studied at 84 MeV incident energy. The ejectiles have been momentum analized by the MAGNEX spectrometer and 15C excitation energy spectra have been obtained up to about 20 MeV. In the region above the two-neutron separation energy, a bump has been observed at 13.7 MeV. The extracted cross section angular distribution for this structure, obtained by using different models for background, displays a clear oscillating pattern, typical of resonant state of the residual nucleus.

  2. Magma viscosity estimation based on analysis of erupted products. Potential assessment for large-scale pyroclastic eruptions

    International Nuclear Information System (INIS)

    Takeuchi, Shingo

    2010-01-01

    After the formulation of guidelines for volcanic hazards in site evaluation for nuclear installations (e.g. JEAG4625-2009), it is required to establish appropriate methods to assess potential of large-scale pyroclastic eruptions at long-dormant volcanoes, which is one of the most hazardous volcanic phenomena on the safety of the installations. In considering the volcanic dormancy, magma eruptability is an important concept. The magma eruptability is dominantly controlled by magma viscosity, which can be estimated from petrological analysis of erupted materials. Therefore, viscosity estimation of magmas erupted in past eruptions should provide important information to assess future activities at hazardous volcanoes. In order to show the importance of magma viscosity in the concept of magma eruptability, this report overviews dike propagation processes from a magma chamber and nature of magma viscosity. Magma viscosity at pre-eruptive conditions of magma chambers were compiled based on previous petrological studies on past eruptions in Japan. There are only 16 examples of eruptions at 9 volcanoes satisfying data requirement for magma viscosity estimation. Estimated magma viscosities range from 10 2 to 10 7 Pa·s for basaltic to rhyolitic magmas. Most of examples fall below dike propagation limit of magma viscosity (ca. 10 6 Pa·s) estimated based on a dike propagation model. Highly viscous magmas (ca. 10 7 Pa·s) than the dike propagation limit are considered to lose eruptability which is the ability to form dikes and initiate eruptions. However, in some cases, small precursory eruptions of less viscous magmas commonly occurred just before climactic eruptions of the highly viscous magmas, suggesting that the precursory dike propagation by the less viscous magmas induced the following eruptions of highly viscous magmas (ca. 10 7 Pa·s). (author)

  3. Cocoa extract intake for 4 weeks reduces postprandial systolic blood pressure response of obese subjects, even after following an energy-restricted diet

    Science.gov (United States)

    Ibero-Baraibar, Idoia; Suárez, Manuel; Arola-Arnal, Anna; Zulet, M. Angeles; Martinez, J. Alfredo

    2016-01-01

    Background Cardiometabolic profile is usually altered in obesity. Interestingly, the consumption of flavanol-rich foods might be protective against those metabolic alterations. Objective To evaluate the postprandial cardiometabolic effects after the acute consumption of cocoa extract before and after 4 weeks of its daily intake. Furthermore, the bioavailability of cocoa extract was investigated. Design Twenty-four overweight/obese middle-aged subjects participated in a 4-week intervention study. Half of the volunteers consumed a test meal enriched with 1.4 g of cocoa extract (415 mg flavanols), while the rest of the volunteers consumed the same meal without the cocoa extract (control group). Glucose and lipid profile, as well as blood pressure and cocoa metabolites in plasma, were assessed before and at 60, 120, and 180 min post-consumption, at the beginning of the study (Postprandial 1) and after following a 4-week 15% energy-restricted diet including meals containing or not containing the cocoa extract (Postprandial 2). Results In the Postprandial 1 test, the area under the curve (AUC) of systolic blood pressure (SBP) was significantly higher in the cocoa group compared with the control group (p=0.007), showing significant differences after 120 min of intake. However, no differences between groups were observed at Postprandial 2. Interestingly, the reduction of postprandial AUC of SBP (AUC_Postprandial 2-AUC_Postprandial 1) was higher in the cocoa group (p=0.016). Furthermore, cocoa-derived metabolites were detected in plasma of the cocoa group, while the absence or significantly lower amounts of metabolites were found in the control group. Conclusions The daily consumption of cocoa extract within an energy-restricted diet for 4 weeks resulted in a greater reduction of postprandial AUC of SBP compared with the effect of energy-restricted diet alone and independently of body weight loss. These results suggest the role of cocoa flavanols on postprandial blood

  4. Cocoa extract intake for 4 weeks reduces postprandial systolic blood pressure response of obese subjects, even after following an energy-restricted diet

    Directory of Open Access Journals (Sweden)

    Idoia Ibero-Baraibar

    2016-03-01

    Full Text Available Background: Cardiometabolic profile is usually altered in obesity. Interestingly, the consumption of flavanol-rich foods might be protective against those metabolic alterations. Objective: To evaluate the postprandial cardiometabolic effects after the acute consumption of cocoa extract before and after 4 weeks of its daily intake. Furthermore, the bioavailability of cocoa extract was investigated. Design: Twenty-four overweight/obese middle-aged subjects participated in a 4-week intervention study. Half of the volunteers consumed a test meal enriched with 1.4 g of cocoa extract (415 mg flavanols, while the rest of the volunteers consumed the same meal without the cocoa extract (control group. Glucose and lipid profile, as well as blood pressure and cocoa metabolites in plasma, were assessed before and at 60, 120, and 180 min post-consumption, at the beginning of the study (Postprandial 1 and after following a 4-week 15% energy-restricted diet including meals containing or not containing the cocoa extract (Postprandial 2. Results: In the Postprandial 1 test, the area under the curve (AUC of systolic blood pressure (SBP was significantly higher in the cocoa group compared with the control group (p=0.007, showing significant differences after 120 min of intake. However, no differences between groups were observed at Postprandial 2. Interestingly, the reduction of postprandial AUC of SBP (AUC_Postprandial 2-AUC_Postprandial 1 was higher in the cocoa group (p=0.016. Furthermore, cocoa-derived metabolites were detected in plasma of the cocoa group, while the absence or significantly lower amounts of metabolites were found in the control group. Conclusions: The daily consumption of cocoa extract within an energy-restricted diet for 4 weeks resulted in a greater reduction of postprandial AUC of SBP compared with the effect of energy-restricted diet alone and independently of body weight loss. These results suggest the role of cocoa flavanols on

  5. Cocoa extract intake for 4 weeks reduces postprandial systolic blood pressure response of obese subjects, even after following an energy-restricted diet.

    Science.gov (United States)

    Ibero-Baraibar, Idoia; Suárez, Manuel; Arola-Arnal, Anna; Zulet, M Angeles; Martinez, J Alfredo

    2016-01-01

    Cardiometabolic profile is usually altered in obesity. Interestingly, the consumption of flavanol-rich foods might be protective against those metabolic alterations. To evaluate the postprandial cardiometabolic effects after the acute consumption of cocoa extract before and after 4 weeks of its daily intake. Furthermore, the bioavailability of cocoa extract was investigated. Twenty-four overweight/obese middle-aged subjects participated in a 4-week intervention study. Half of the volunteers consumed a test meal enriched with 1.4 g of cocoa extract (415 mg flavanols), while the rest of the volunteers consumed the same meal without the cocoa extract (control group). Glucose and lipid profile, as well as blood pressure and cocoa metabolites in plasma, were assessed before and at 60, 120, and 180 min post-consumption, at the beginning of the study (Postprandial 1) and after following a 4-week 15% energy-restricted diet including meals containing or not containing the cocoa extract (Postprandial 2). In the Postprandial 1 test, the area under the curve (AUC) of systolic blood pressure (SBP) was significantly higher in the cocoa group compared with the control group (p=0.007), showing significant differences after 120 min of intake. However, no differences between groups were observed at Postprandial 2. Interestingly, the reduction of postprandial AUC of SBP (AUC_Postprandial 2-AUC_Postprandial 1) was higher in the cocoa group (p=0.016). Furthermore, cocoa-derived metabolites were detected in plasma of the cocoa group, while the absence or significantly lower amounts of metabolites were found in the control group. The daily consumption of cocoa extract within an energy-restricted diet for 4 weeks resulted in a greater reduction of postprandial AUC of SBP compared with the effect of energy-restricted diet alone and independently of body weight loss. These results suggest the role of cocoa flavanols on postprandial blood pressure homeostasis.

  6. Incorporation of Tongkat Ali and Ginseng extracts from mass propagated roots derived from bioreactor technology as supplements in energy chocolate confectionery

    International Nuclear Information System (INIS)

    Seri Cempaka Mohd Yusof; Sobri Hussein; Salmah Moosa; Salahbiah Badul Majid; Azhar Mohammad; Foziah Ali; Shafii Khamis; Rusli Ibrahim

    2012-01-01

    Tongkat Ali (Eurycoma longifolia) and Ginseng (Panax ginseng) are well known herbs among Asians and have been sought after by Europeans and others for the benefits to health, especially as aphrodisiac and nourishing stimulants. They have high antioxidant level and were reported to be used in the treatment of type II diabetes, as well as for sexual dysfunction in men. Since Tongkat Ali and Ginseng are difficult to cultivate and have a long cultivation period, the bioreactor technology is the alternative method to produce huge amount of raw materials for the herbal industry and continuous supply of standardized raw materials that is not affected by geographical and environmental factors, soil less and free from pesticides and other contaminants. Tongkat Ali and Ginseng extracts from mass propagated roots derived from bioreactor technology have similar profiles as extracts derived from normal cultivation. Liquid Chromatography-Mass Spectrometer (LC-MS) profiles showed presence of active compounds in the Tongkat Ali and Ginseng extracts from the mass propagated roots. Cytotoxicity test using the brine shrimp (Artemia salina Leach) lethality assay, revealed that higher concentration of Tongkat Ali and Ginseng extracts from mass propagated roots did not kill or affect the brine shrimps, implying that the extracts were safe for consumption. Incorporation of combination of Tongkat Ali and Ginseng total extracts from mass propagated roots derived from bioreactor technology energy chocolate confectionery was accepted by the panelists in sensory evaluation and showed that the chocolate product has good potential as a carrier besides beverages and capsules. (author)

  7. Radioactive equilibria and disequilibria of U-series nuclides in erupting magmas from Izu arc volcanoes

    International Nuclear Information System (INIS)

    Sato, Jun; Kurihara, Yuichi; Takahashi, Masaomi

    2009-01-01

    Radioactive disequilibria among U-series nuclides are observed in the magmas from volcanoes in the world. Basaltic products from Izu arc volcanoes, including Izu-Oshima and Fuji volcanoes, show 230 Th 238 U and 226 Ra> 230 Th disequilibria, indicating that the addition of U-and Ra-rich fluid from the subducting slab to the mantle wedge at the magma genesis. The disequilibria of 226 Ra> 230 Th in the erupting magmas suggest that the timescale from magma genesis to the eruption may be less than 8000 years. (author)

  8. Long-Term Volumetric Eruption Rates and Magma Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Scott M. White Dept. Geological Sciences University of South Carolina Columbia, SC 29208; Joy A. Crisp Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA 91109; Frank J. Spera Dept. Earth Science University of California, Santa Barbara Santa Barbara, CA 93106

    2005-01-01

    A global compilation of 170 time-averaged volumetric volcanic output rates (Qe) is evaluated in terms of composition and petrotectonic setting to advance the understanding of long-term rates of magma generation and eruption on Earth. Repose periods between successive eruptions at a given site and intrusive:extrusive ratios were compiled for selected volcanic centers where long-term (>104 years) data were available. More silicic compositions, rhyolites and andesites, have a more limited range of eruption rates than basalts. Even when high Qe values contributed by flood basalts (9 ± 2 Å~ 10-1 km3/yr) are removed, there is a trend in decreasing average Qe with lava composition from basaltic eruptions (2.6 ± 1.0 Å~ 10-2 km3/yr) to andesites (2.3 ± 0.8 Å~ 10-3 km3/yr) and rhyolites (4.0 ± 1.4 Å~ 10-3 km3/yr). This trend is also seen in the difference between oceanic and continental settings, as eruptions on oceanic crust tend to be predominately basaltic. All of the volcanoes occurring in oceanic settings fail to have statistically different mean Qe and have an overall average of 2.8 ± 0.4 Å~ 10-2 km3/yr, excluding flood basalts. Likewise, all of the volcanoes on continental crust also fail to have statistically different mean Qe and have an overall average of 4.4 ± 0.8 Å~ 10-3 km3/yr. Flood basalts also form a distinctive class with an average Qe nearly two orders of magnitude higher than any other class. However, we have found no systematic evidence linking increased intrusive:extrusive ratios with lower volcanic rates. A simple heat balance analysis suggests that the preponderance of volcanic systems must be open magmatic systems with respect to heat and matter transport in order to maintain eruptible magma at shallow depth throughout the observed lifetime of the volcano. The empirical upper limit of Å`10-2 km3/yr for magma eruption rate in systems with relatively high intrusive:extrusive ratios may be a consequence of the fundamental parameters

  9. Grain to outcrop-scale frozen moments of dynamic magma mixing in the syenite magma chamber, Yelagiri Alkaline Complex, South India

    Directory of Open Access Journals (Sweden)

    M.L. Renjith

    2014-11-01

    Full Text Available Magma mixing process is unusual in the petrogenesis of felsic rocks associated with alkaline complex worldwide. Here we present a rare example of magma mixing in syenite from the Yelagiri Alkaline Complex, South India. Yelagiri syenite is a reversely zoned massif with shoshonitic (Na2O + K2O=5–10 wt.%, Na2O/K2O = 0.5–2, TiO2 <0.7 wt.% and metaluminous character. Systematic modal variation of plagioclase (An11–16 Ab82–88, K-feldspar (Or27–95 Ab5–61, diopside (En34–40Fs11–18Wo46–49, biotite, and Ca-amphibole (edenite build up three syenite facies within it and imply the role of in-situ fractional crystallization (FC. Evidences such as (1 disequilibrium micro-textures in feldspars, (2 microgranular mafic enclaves (MME and (3 synplutonic dykes signify mixing of shoshonitic mafic magma (MgO = 4–5 wt.%, SiO2 = 54–59 wt.%, K2O/Na2O = 0.4–0.9 with syenite. Molecular-scale mixing of mafic magma resulted disequilibrium growth of feldspars in syenite. Physical entity of mafic magma preserved as MME due to high thermal-rheological contrast with syenite magma show various hybridization through chemical exchange, mechanical dilution enhanced by chaotic advection and phenocryst migration. In synplutonic dykes, disaggregation and mixing of mafic magma was confined within the conduit of injection. Major-oxides mass balance test quantified that approximately 0.6 portions of mafic magma had interacted with most evolved syenite magma and generated most hybridized MME and dyke samples. It is unique that all the rock types (syenite, MME and synplutonic dykes share similar shoshonitic and metaluminous character; mineral chemistry, REE content, coherent geochemical variation in Harker diagram suggest that mixing of magma between similar composition. Outcrop-scale features of crystal accumulation and flow fabrics also significant along with MME and synplutonic dykes in syenite suggesting that Yelagiri syenite magma chamber had evolved

  10. Boron Isotope Compositions of Selected Fresh MORB Glasses From the Northern EPR (8-10° N): Implications for MORB Magma Contamination

    Science.gov (United States)

    Le Roux, P. J.; Shirey, S. B.; Hauri, E. H.; Perfit, M. R.

    2003-12-01

    . These MORB samples have 0.56 to 2.61 ppm B, and B isotope compositions that are surprisingly restricted ranging from δ 11B -5.50 to -8.96‰ . The low δ 11B values are close to the depleted upper mantle value (-10‰ ). The δ 11B data do not correlation with B concentrations, Mg#, Sr, Nd or Pb isotopes, or proxies for brine addition (e.g. Cl/Nb). The lowest δ 11B samples are also the most-incompatible element depleted (high B/Nb ratios). The δ 11B of the on-axis samples increases slightly with increased levels of magma degassing (i.e. lowest δ 11B values in samples extracted undegassed from depths closest to AMC top).Therefore, although the Cl data indicate significant addition of probably a saline brine component to both on- and off-axis MORB magmas, their δ 11B compositions were not significantly affected by this process and the observed variations in δ 11B may have a different origin. Possibly, the low B/Cl ratio of seawater ( ˜ 0.001) coupled with preferential partitioning of Cl relative to B into brines during supercritical phase separation (Berndt and Seyfried, 1990) of seawater in hydrothermal system, results in very saline brines with low boron concentrations. The coupled B-Cl data effectively eliminates simple magmatic assimilation of altered Cl-rich high-B isotope composition oceanic crust in this region.

  11. In vitro Study of Noni Juice Extract Waste (Morinda citrifolia L.) and Pineapple Industrial Wastes (Ananas comosus L. Merr) as Energy Supplement in Dairy Goat Ration

    Science.gov (United States)

    Evvyernie, D.; Tjakradidjaja, A. S.; Permana, I. G.; Toharmat, T.; Insani, A.

    2018-02-01

    The aim of the study was to evaluate the potency of noni juice extract waste (Morinda citrifolia L.) and pineapple industrial wastes (Ananas comosus L. Merr) as an energy supplement in dairy goat ration through in vitro study. This study used a complete randomized design with 5 treatments and 3 rumen fluid groups. The treatments were R0 as control (60% Napier grass (NG) + 40% concentrate), R1 (45% NG + 15% noni juice extract waste + 40% concentrate) + R2 (45% NG + 15% noni juice extract waste ammoniated + 40% concentrate), R3 (45% NG + 15% pineapple peel + 40% concentrate), and R4 (45% NG + 15% pineapple crown + 40% concentrate). The variables were totalbacterial population, protozoal population, fermentation characteristic (total VFA and NH3 concentration), and digestibility (dry matter and organic matter).Data were analyzed with analysis of variance (ANOVA) and differences among treatments were determined by orthogonal contrast.The results showed that total VFA concentration was significant increased (Ppineapple peel (R3). The average increasing of total VFA concentration was 74% compared to control. As conclusions, 15% pineapple peel or 15% noni juice extract waste can use as an energy supplement by replacing 25% of napier grass in lactating dairy goat ration.

  12. Impact of plant extracts tested in attention-deficit/hyperactivity disorder treatment on cell survival and energy metabolism in human neuroblastoma SH-SY5Y cells.

    Science.gov (United States)

    Schmidt, Andreas Johannes; Krieg, Jürgen-Christian; Hemmeter, Ulrich Michael; Kircher, Tilo; Schulz, Eberhard; Clement, Hans-Willi; Heiser, Philip

    2010-10-01

    Plant extracts such as Hypericum perforatum and Pycnogenol have been tested as alternatives to the classical ADHD drugs. It has been possible to describe neuroprotective effects of such plant extracts. A reduction of ADHD symptoms could be shown in clinical studies after the application of Pycnogenol, which is a pine bark extract. The impacts of the standardized herbal extracts Hypericum perforatum, Pycnogenol and Enzogenol up to a concentration of 5000 ng/mL on cell survival and energy metabolism in human SH-SY5Y neuroblastoma cells has been investigated in the present examination. Hypericum perforatum significantly decreased the survival of cells after treatment with a concentration of 5000 ng/mL, whereas lower concentrations exerted no significant effects. Pycnogenol( induced a significant increase of cell survival after incubation with a concentration of 32.25 ng/mL and a concentration of 250 ng/mL. Other applied concentrations of Pycnogenol failed to exert significant effects. Treatment with Enzogenol did not lead to significant changes in cell survival.Concerning energy metabolism, the treatment of cells with a concentration of 5000 ng/mL Hypericum perforatum led to a significant increase of ATP levels, whereas treatment with a concentration of 500 ng/mL had no significant effect. Incubation of cells with Pycnogenol and Enzogenol exerted no significant effects.None of the tested substances caused any cytotoxic effect when used in therapeutically relevant concentrations. Copyright © 2010 John Wiley & Sons, Ltd.

  13. Urgency in energy justice : contestation and time in prospective shale extraction in the United States and United Kingdom

    OpenAIRE

    Partridge, Tristan

    2018-01-01

    Changes to the material and social systems that underpin energy infrastructures are inextricably linked to energy justice concerns, and the timeframes of those changes significantly affect their outcomes. Temporal aspects of energy initiatives and their impacts are thus an important site for examining emergent public views on new energy proposals, inequality, and energy justice. We propose urgency is a particularly rich concept through which to study (i) the justice and socioenvironmental imp...

  14. Magma interaction in the root of an arc batholith

    Science.gov (United States)

    Chapman, T.; Robbins, V.; Clarke, G. L.; Daczko, N. R.; Piazolo, S.

    2016-12-01

    Fiordland, New Zealand, preserves extensive Cretaceous arc plutons, emplaced into parts of the Delamerian/Ross Orogen. Dioritic to gabbroic material emplaced at mid to lower crustal levels are exposed in the Malaspina Pluton (c. 1.2 GPa) and the Breaksea Orthogneiss (c. 1.8 GPa). Distinct magmatic pulses can be mapped in both of these plutons consistent with cycles of melt advection. Relationships are consistent with predictions from lower crustal processing zones (MASH and hot zones) considered important in the formation of Cordilleran margins. Metamorphic garnet growth is enhanced along magmatic contacts, such as where hornblende gabbronorite is cut by garnet-clinopyroxene-bearing diorite. Such features are consistent with cycles of incremental emplacement, younger magma having induced localised garnet granulite metamorphism in wall rock of older material. Temperature estimates and microstructures preserved in garnet granulite are consistent with sub-solidus, water-poor conditions in both the Malaspina and Breaksea Orthogneiss. The extent and conditions of the metamorphism implies conditions and duration was incapable of partially melting older wall rock material. The nature of interactions in intermediate to basic compositions are assessed in terms of magma genesis in the Cretaceous batholith. Most of the upper crustal felsic I-type magmatism along the margin being controlled by high-pressure garnet-clinopyroxene fractionation.

  15. Boron isotope fractionation in magma via crustal carbonate dissolution.

    Science.gov (United States)

    Deegan, Frances M; Troll, Valentin R; Whitehouse, Martin J; Jolis, Ester M; Freda, Carmela

    2016-08-04

    Carbon dioxide released by arc volcanoes is widely considered to originate from the mantle and from subducted sediments. Fluids released from upper arc carbonates, however, have recently been proposed to help modulate arc CO2 fluxes. Here we use boron as a tracer, which substitutes for carbon in limestone, to further investigate crustal carbonate degassing in volcanic arcs. We performed laboratory experiments replicating limestone assimilation into magma at crustal pressure-temperature conditions and analysed boron isotope ratios in the resulting experimental glasses. Limestone dissolution and assimilation generates CaO-enriched glass near the reaction site and a CO2-dominated vapour phase. The CaO-rich glasses have extremely low δ(11)B values down to -41.5‰, reflecting preferential partitioning of (10)B into the assimilating melt. Loss of (11)B from the reaction site occurs via the CO2 vapour phase generated during carbonate dissolution, which transports (11)B away from the reaction site as a boron-rich fluid phase. Our results demonstrate the efficacy of boron isotope fractionation during crustal carbonate assimilation and suggest that low δ(11)B melt values in arc magmas could flag shallow-level additions to the subduction cycle.

  16. MAGMA-SMC: The Molecular Cloud Survey of the SMC

    Science.gov (United States)

    Muller, Erik; Wong, Tony; Hughes, Annie; Ott, Jürgen; Pineda, Jorge L.; MAGMA Collaboration

    2013-03-01

    We present a brief summary and description of the upcoming 12CO(1-0) Magellanic Mopra Assesment (MAGMA) SMC survey data release. The MAGMA-SMC survey has sampled 100% of the known CO in the SMC (at ˜33″ resolution; 12 pc at D = 60 kpc). Having explored 522 × 103 square parsecs throughout the SMC with 69 5' × 5' fields, to a sensitivity of ˜150 mK, we apply the cloudprops (Rosolowsky & Leroy 2006) cloud-search algorithm optimized for low S/N data, to detect more than 30 CO clouds with virial masses between 103-104 M⊙, mean radii ˜5 pc and 0.3-0.9 km s-1 velocity width. Typical brightness temperatures are ˜1 K T mb . All detected molecular regions are associated with at least one 24 μm compact emission source. Smoothing rarely increases the total detected CO flux, implying the CO emission is typically confined to small spatial scales. As recent dust maps of the SMC imply extended H2 mass, the apparent compact nature of the CO population indicates some departures from the canonical Galactic X CO-factor in the low-metallicity and relatively un-evolved ISM of the SMC.

  17. Boron isotope fractionation in magma via crustal carbonate dissolution

    Science.gov (United States)

    Deegan, Frances M.; Troll, Valentin R.; Whitehouse, Martin J.; Jolis, Ester M.; Freda, Carmela

    2016-08-01

    Carbon dioxide released by arc volcanoes is widely considered to originate from the mantle and from subducted sediments. Fluids released from upper arc carbonates, however, have recently been proposed to help modulate arc CO2 fluxes. Here we use boron as a tracer, which substitutes for carbon in limestone, to further investigate crustal carbonate degassing in volcanic arcs. We performed laboratory experiments replicating limestone assimilation into magma at crustal pressure-temperature conditions and analysed boron isotope ratios in the resulting experimental glasses. Limestone dissolution and assimilation generates CaO-enriched glass near the reaction site and a CO2-dominated vapour phase. The CaO-rich glasses have extremely low δ11B values down to -41.5‰, reflecting preferential partitioning of 10B into the assimilating melt. Loss of 11B from the reaction site occurs via the CO2 vapour phase generated during carbonate dissolution, which transports 11B away from the reaction site as a boron-rich fluid phase. Our results demonstrate the efficacy of boron isotope fractionation during crustal carbonate assimilation and suggest that low δ11B melt values in arc magmas could flag shallow-level additions to the subduction cycle.

  18. Optimization of two methods based on ultrasound energy as alternative to European standards for soluble salts extraction from building materials.

    Science.gov (United States)

    Prieto-Taboada, N; Gómez-Laserna, O; Martinez-Arkarazo, I; Olazabal, M A; Madariaga, J M

    2012-11-01

    The Italian recommendation NORMAL 13/83, later replaced by the UNI 11087/2003 norm, were used as standard for soluble salts extraction from construction materials. These standards are based on long-time stirring (72 and 2h, respectively) of the sample in deionized water. In this work two ultrasound based methods were optimized in order to reduce the extraction time while efficiency is improved. The instrumental variables involved in the extraction assisted by ultrasound bath and focused ultrasounds were optimized by experimental design. As long as it was possible, the same non-instrumental parameters values as those of standard methods were used in order to compare the results obtained on a mortar sample showing a black crust by the standards and the optimized methods. The optimal extraction time for the ultrasounds bath was found to be of two hours. Although the extraction time was equal to the standard UNI 11087/2003, the obtained extraction recovery was improved up to 119%. The focused ultrasound system achieved also better recoveries (up to 106%) depending on the analyte in 1h treatment time. The repeatabilities of the proposed ultrasound based methods were comparables to those of the standards. Therefore, the selection of one or the other of the ultrasound based methods will depend on topics such as laboratory facilities or number of samples, and not in aspects related with their quality parameters. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Calibration of high-dynamic-range, finite-resolution x-ray pulse-height spectrometers for extracting electron energy distribution data from the PFRC-2 device

    Science.gov (United States)

    Swanson, C.; Jandovitz, P.; Cohen, S. A.

    2017-10-01

    Knowledge of the full x-ray energy distribution function (XEDF) emitted from a plasma over a large dynamic range of energies can yield valuable insights about the electron energy distribution function (EEDF) of that plasma and the dynamic processes that create them. X-ray pulse height detectors such as Amptek's X-123 Fast SDD with Silicon Nitride window can detect x-rays in the range of 200eV to 100s of keV. However, extracting EEDF from this measurement requires precise knowledge of the detector's response function. This response function, including the energy scale calibration, the window transmission function, and the resolution function, can be measured directly. We describe measurements of this function from x-rays from a mono-energetic electron beam in a purpose-built gas-target x-ray tube. Large-Z effects such as line radiation, nuclear charge screening, and polarizational Bremsstrahlung are discussed.

  20. A three-layer model of self-assembly induced surface-energy variation experimentally extracted by using nanomechanically sensitive cantilevers

    International Nuclear Information System (INIS)

    Zuo Guomin; Li Xinxin

    2011-01-01

    This research is aimed at elucidating surface-energy (or interfacial energy) variation during the process of molecule-layer self-assembly on a solid surface. A quasi-quantitative plotting model is proposed and established to distinguish the surface-energy variation contributed by the three characteristic layers of a thiol-on-gold self-assembled monolayer (SAM), namely the assembly-medium correlative gold/head-group layer, the chain/chain interaction layer and the tail/medium layer, respectively. The data for building the model are experimentally extracted from a set of correlative thiol self-assemblies in different media. The variation in surface-energy during self-assembly is obtained by in situ recording of the self-assembly induced nanomechanical surface-stress using integrated micro-cantilever sensors. Based on the correlative self-assembly experiment, and by using the nanomechanically sensitive self-sensing cantilevers to monitor the self-assembly induced surface-stressin situ, the experimentally extracted separate contributions of the three layers to the overall surface-energy change aid a comprehensive understanding of the self-assembly mechanism. Moreover, the quasi-quantitative modeling method is helpful for optimal design, molecule synthesis and performance evaluation of molecule self-assembly for application-specific surface functionalization.

  1. Volatile-induced magma differentiation in the plumbing system of Mt. Etna volcano (Italy): evidence from glass in tephra of the 2001 eruption

    Science.gov (United States)

    Ferlito, Carmelo; Viccaro, Marco; Cristofolini, Renato

    2008-02-01

    Mount Etna volcano was shaken during the summer 2001 by one of the most singular eruptive episodes of the last centuries. For about 3 weeks, several eruptive fractures developed, emitting lava flows and tephra that significantly modified the landscape of the southern flank of the volcano. This event stimulated the attention of the scientific community especially for the simultaneous emission of petrologically distinct magmas, recognized as coming from different segments of the plumbing system. A stratigraphically controlled sampling of tephra layers was performed at the most active vents of the eruption, in particular at the 2,100 m (CAL) and at the 2,550 m (LAG) scoria cones. Detailed scanning electron microscope and energy dispersive x-ray spectrometer (SEM-EDS) analyses performed on glasses found in tephra and comparison with lava whole rock compositions indicate an anomalous increase in Ti, Fe, P, and particularly of K and Cl in the upper layers of the LAG sequence. Mass balance and thermodynamic calculations have shown that this enrichment cannot be accounted for by “classical” differentiation processes, such as crystal fractionation and magma mixing. The analysis of petrological features of the magmas involved in the event, integrated with the volcanological evolution, has evidenced the role played by volatiles in controlling the magmatic evolution within the crustal portion of the plumbing system. Volatiles, constituted of H2O, CO2, and Cl-complexes, originated from a deeply seated magma body (DBM). Their upward migration occurred through a fracture network possibly developed by the seismic swarms during the period preceding the event. In the upper portion of the plumbing system, a shallower residing magma body (ABT) had chemical and physical conditions to receive migrating volatiles, which hence dissolved the mobilized elements producing the observed selective enrichment. This volatile-induced differentiation involved exclusively the lowest erupted

  2. Timescales of Quartz Crystallization and the Longevity of the Bishop Giant Magma Body

    Energy Technology Data Exchange (ETDEWEB)

    Gualda, Guilherme A.R.; Pamukcu, Ayla S.; Ghiorso, Mark S.; Anderson, Jr. , Alfred T.; Sutton, Stephen R.; Rivers, Mark L. (OFM Res.); (Vanderbilt); (UC)

    2013-04-08

    Supereruptions violently transfer huge amounts (100 s-1000 s km{sup 3}) of magma to the surface in a matter of days and testify to the existence of giant pools of magma at depth. The longevity of these giant magma bodies is of significant scientific and societal interest. Radiometric data on whole rocks, glasses, feldspar and zircon crystals have been used to suggest that the Bishop Tuff giant magma body, which erupted {approx}760,000 years ago and created the Long Valley caldera (California), was long-lived (>100,000 years) and evolved rather slowly. In this work, we present four lines of evidence to constrain the timescales of crystallization of the Bishop magma body: (1) quartz residence times based on diffusional relaxation of Ti profiles, (2) quartz residence times based on the kinetics of faceting of melt inclusions, (3) quartz and feldspar crystallization times derived using quartz+feldspar crystal size distributions, and (4) timescales of cooling and crystallization based on thermodynamic and heat flow modeling. All of our estimates suggest quartz crystallization on timescales of <10,000 years, more typically within 500-3,000 years before eruption. We conclude that large-volume, crystal-poor magma bodies are ephemeral features that, once established, evolve on millennial timescales. We also suggest that zircon crystals, rather than recording the timescales of crystallization of a large pool of crystal-poor magma, record the extended periods of time necessary for maturation of the crust and establishment of these giant magma bodies.

  3. Zircon reveals protracted magma storage and recycling beneath Mount St. Helens

    Science.gov (United States)

    Claiborne, L.L.; Miller, C.F.; Flanagan, D.M.; Clynne, M.A.; Wooden, J.L.

    2010-01-01

    Current data and models for Mount St. Helens volcano (Washington, United States) suggest relatively rapid transport from magma genesis to eruption, with no evidence for protracted storage or recycling of magmas. However, we show here that complex zircon age populations extending back hundreds of thousands of years from eruption age indicate that magmas regularly stall in the crust, cool and crystallize beneath the volcano, and are then rejuvenated and incorporated by hotter, young magmas on their way to the surface. Estimated dissolution times suggest that entrained zircon generally resided in rejuvenating magmas for no more than about a century. Zircon elemental compositions reflect the increasing influence of mafic input into the system through time, recording growth from hotter, less evolved magmas tens of thousands of years prior to the appearance of mafic magmas at the surface, or changes in whole-rock geochemistry and petrology, and providing a new, time-correlated record of this evolution independent of the eruption history. Zircon data thus reveal the history of the hidden, long-lived intrusive portion of the Mount St. Helens system, where melt and crystals are stored for as long as hundreds of thousands of years and interact with fresh influxes of magmas that traverse the intrusive reservoir before erupting. ?? 2010 Geological Society of America.

  4. Continental rift architecture and patterns of magma migration: a dynamic analysis based on centrifuge models.

    NARCIS (Netherlands)

    Corti, G.; Bonini, M.; Sokoutis, D.; Innocenti, F.; Manetti, P.; Cloetingh, S.A.P.L.; Mulugeta, G.

    2004-01-01

    Small-scale centrifuge models were used to investigate the role of continental rift structure in controlling patterns of magma migration and emplacement. Experiments considered the reactivation of weakness zones in the lower crust and the presence of magma at Moho depths. Results suggest that

  5. Rapid heterogeneous assembly of multiple magma reservoirs prior to Yellowstone supereruptions.

    Science.gov (United States)

    Wotzlaw, Jörn-Frederik; Bindeman, Ilya N; Stern, Richard A; D'Abzac, Francois-Xavier; Schaltegger, Urs

    2015-09-10

    Large-volume caldera-forming eruptions of silicic magmas are an important feature of continental volcanism. The timescales and mechanisms of assembly of the magma reservoirs that feed such eruptions as well as the durations and physical conditions of upper-crustal storage remain highly debated topics in volcanology. Here we explore a comprehensive data set of isotopic (O, Hf) and chemical proxies in precisely U-Pb dated zircon crystals from all caldera-forming eruptions of Yellowstone supervolcano. Analysed zircons record rapid assembly of multiple magma reservoirs by repeated injections of isotopically heterogeneous magma batches and short pre-eruption storage times of 10(3) to 10(4) years. Decoupled oxygen-hafnium isotope systematics suggest a complex source for these magmas involving variable amounts of differentiated mantle-derived melt, Archean crust and hydrothermally altered shallow-crustal rocks. These data demonstrate that complex magma reservoirs with multiple sub-chambers are a common feature of rift- and hotspot related supervolcanoes. The short duration of reservoir assembly documents rapid crustal remelting and two to three orders of magnitude higher magma production rates beneath Yellowstone compared to continental arc volcanoes. The short pre-eruption storage times further suggest that the detection of voluminous reservoirs of eruptible magma beneath active supervolcanoes may only be possible prior to an impending eruption.

  6. Timescales of quartz crystallization and the longevity of the Bishop giant magma body.

    Science.gov (United States)

    Gualda, Guilherme A R; Pamukcu, Ayla S; Ghiorso, Mark S; Anderson, Alfred T; Sutton, Stephen R; Rivers, Mark L

    2012-01-01

    Supereruptions violently transfer huge amounts (100 s-1000 s km(3)) of magma to the surface in a matter of days and testify to the existence of giant pools of magma at depth. The longevity of these giant magma bodies is of significant scientific and societal interest. Radiometric data on whole rocks, glasses, feldspar and zircon crystals have been used to suggest that the Bishop Tuff giant magma body, which erupted ~760,000 years ago and created the Long Valley caldera (California), was long-lived (>100,000 years) and evolved rather slowly. In this work, we present four lines of evidence to constrain the timescales of crystallization of the Bishop magma body: (1) quartz residence times based on diffusional relaxation of Ti profiles, (2) quartz residence times based on the kinetics of faceting of melt inclusions, (3) quartz and feldspar crystallization times derived using quartz+feldspar crystal size distributions, and (4) timescales of cooling and crystallization based on thermodynamic and heat flow modeling. All of our estimates suggest quartz crystallization on timescales of magma bodies are ephemeral features that, once established, evolve on millennial timescales. We also suggest that zircon crystals, rather than recording the timescales of crystallization of a large pool of crystal-poor magma, record the extended periods of time necessary for maturation of the crust and establishment of these giant magma bodies.

  7. Compressible magma flow in a two-dimensional elastic-walled dike

    NARCIS (Netherlands)

    Woods, A.W.; Bokhove, Onno; de Boer, A; Hill, B.E.

    2006-01-01

    The ascent of magma to the Earth's surface is commonly modeled by assuming a fixed dike or flow geometry from a deep subsurface reservoir to the surface. In practice, however, this flow geometry is produced by deformation of the crust by ascending overpressured magma. Here, we explore how this

  8. Pricing strategies in inelastic energy markets : can we use less if we can’t extract more?

    NARCIS (Netherlands)

    Voinov, A.; Filatova, Tatiana

    2014-01-01

    Limited supply of nonrenewable energy resources under growing energy demand creates a situation when a marginal change in the quantity supplied or demanded causes non-marginal swings in price levels. The situation is worsened by the fact that we are currently running out of cheap energy resources at

  9. Pricing strategies in inelastic energy markets: can we use less if we can't extract more?

    Science.gov (United States)

    Voinov, Alexey; Filatova, Tatiana

    2014-03-01

    Limited supply of nonrenewable energy resources under growing energy demand creates a situation when a marginal change in the quantity supplied or demanded causes non-marginal swings in price levels. The situation is worsened by the fact that we are currently running out of cheap energy resources at the global scale while adaptation to climate change requires extra energy costs. It is often argued that technology and alternative energy will be a solution. However, alternative energy infrastructure also requires additional energy investments, which can further increase the gap between energy demand and supply. This paper presents an explorative model that demonstrates that a smooth transition from an oil-based economy to alternative energy sources is possible only if it is started well in advance while fossil resources are still abundant. Later the transition looks much more dramatic and it becomes risky to rely entirely on technological solutions. It becomes increasingly likely that in addition to technological solutions that can increase supply we will need to find ways to decrease demand and consumption. We further argue that market mechanisms can be just as powerful tools to curb demand as they have traditionally been for stimulating consumption. We observe that individuals who consume more energy resources benefit at the expense of those who consume less, effectively imposing price externalities on the latters. We suggest two transparent and flexible methods of pricing that attempt to eliminate price externalities on energy resources. Such pricing schemes stimulate less consumption and can smooth the transition to renewable energy.

  10. On the conditions of magma mixing and its bearing on andesite production in the crust.

    Science.gov (United States)

    Laumonier, Mickael; Scaillet, Bruno; Pichavant, Michel; Champallier, Rémi; Andujar, Joan; Arbaret, Laurent

    2014-12-15

    Mixing between magmas is thought to affect a variety of processes, from the growth of continental crust to the triggering of volcanic eruptions, but its thermophysical viability remains unclear. Here, by using high-pressure mixing experiments and thermal calculations, we show that hybridization during single-intrusive events requires injection of high proportions of the replenishing magma during short periods, producing magmas with 55-58 wt% SiO2 when the mafic end-member is basaltic. High strain rates and gas-rich conditions may produce more felsic hybrids. The incremental growth of crustal reservoirs limits the production of hybrids to the waning stage of pluton assembly and to small portions of it. Large-scale mixing appears to be more efficient at lower crustal conditions, but requires higher proportions of mafic melt, producing more mafic hybrids than in shallow reservoirs. Altogether, our results show that hybrid arc magmas correspond to periods of enhanced magma production at depth.

  11. Evidence for crustal recycling during the Archean: the parental magmas of the stillwater complex

    International Nuclear Information System (INIS)

    McCallum, I.S.

    1988-01-01

    The petrology and geochemistry of the Stillwater Complex, an Archean (2.7 Ga) layered mafic intrusion in the Beartooth Mountains of Montana, is discussed. Efforts to reconstruct the compositions of possible parental magmas and thereby place some constraints on the composition and history of their mantle source regions was studied. A high-Mg andesite or boninite magma best matches the crystallization sequences and mineral compositions of Stillwater cumulates, and represents either a primary magma composition or a secondary magma formed, for example, by assimilation of crustal material by a very Mg-rich melt such as komatiite. Isotopic data do not support the extensive amounts of assimilation required by the komatiite parent hypothesis, and it is argued that the Stillwater magma was generated from a mantle source that had been enriched by recycling and homogenization of older crustal material over a large area

  12. «Magma»: as origens de Guimarães Rosa

    Directory of Open Access Journals (Sweden)

    Luiz Cláudio Vieira de Oliveira

    2011-10-01

    Full Text Available Resumo: Leitura de Magma, de Guimarães Rosa, com o objetivo de indicar a presença de temas, fragmentos, personagens, expressões e recursos estilísticos ali existentes, em outros textos do autor, cronologicamente posteriores.Palavras-chave: Literatura brasileira; Guimarães Rosa; Magma.Résumé: Lecture de Magma, de Guimarães Rosa, ayant l’objectif de montrer la présence de quelques sujets, fragments, personnages, expressions et traits stylistiques, que y sont présents, et aussi dans autres textes du même auteur, chronologiquement postérieurs.Mots-clés: Littérature brésilienne; Guimarães Rosa; Magma.Keywords: Brazilian literature; Guimarães Rosa; Magma.

  13. The Effect of Thermal Cycling on Crystal-Liquid Separation During Lunar Magma Ocean Differentiation

    Science.gov (United States)

    Mills, Ryan D.

    2013-01-01

    Differentiation of magma oceans likely involves a mixture of fractional and equilibrium crystallization [1]. The existence of: 1) large volumes of anorthosite in the lunar highlands and 2) the incompatible- rich (KREEP) reservoir suggests that fractional crystallization may have dominated during differentiation of the Moon. For this to have occurred, crystal fractionation must have been remarkably efficient. Several authors [e.g. 2, 3] have hypothesized that equilibrium crystallization would have dominated early in differentiation of magma oceans because of crystal entrainment during turbulent convection. However, recent numerical modeling [4] suggests that crystal settling could have occurred throughout the entire solidification history of the lunar magma ocean if crystals were large and crystal fraction was low. These results indicate that the crystal size distribution could have played an important role in differentiation of the lunar magma ocean. Here, I suggest that thermal cycling from tidal heating during lunar magma ocean crystallization caused crystals to coarsen, leading to efficient crystal-liquid separation.

  14. Rapid mixing and short storage timescale in the magma dynamics of a steady-state volcano

    Science.gov (United States)

    Petrone, Chiara Maria; Braschi, Eleonora; Francalanci, Lorella; Casalini, Martina; Tommasini, Simone

    2018-06-01

    Steady-state volcanic activity implies equilibrium between the rate of magma replenishment and eruption of compositionally homogeneous magmas, lasting for tens to thousands of years in an open conduit system. The Present-day activity of Stromboli volcano (Aeolian Islands, Southern Italy) has long been recognised as typical of a steady-state volcano, with a shallow magmatic reservoir (highly porphyritic or hp-magma) continuously refilled by more mafic magma (with low phenocryst content or lp-magma) at a constant rate and accompanied by mixing, crystallisation and eruption. Our aim is to clarify the timescale and dynamics of the plumbing system at the establishment of the Present-day steady-state activity (volcanoes.

  15. Magma genesis at Gale Crater: Evidence for Pervasive Mantle Metasomatism

    Science.gov (United States)

    Filiberto, J.

    2017-12-01

    Basaltic rocks have been analyzed at Gale Crater with a larger range in bulk chemistry than at any other landing site [1]. Therefore, the rocks may have experienced significantly different formation conditions than those experienced by magmas at Gusev Crater or Meridiani Planum. Specifically, the rocks at Gale Crater have higher potassium than other Martian rocks, with a potential analog of the Nakhlite parental magma, and are consistent with forming from a metasomatized mantle source [2-4]. Mantle metasomatism would not only affect the bulk chemistry but mantle melting conditions, as metasomatism fluxes fluids into the source region. Here I will combine differences in bulk chemistry between Martian basalts to calculate formation conditions in the interior and investigate if the rocks at Gale Crater experienced magma genesis conditions consistent with metasomatism - lower temperatures and pressures of formation. To calculate average formation conditions, I rely on experimental results, where available, and silica-activity and Mg-exchange thermometry calculations for all other compositions following [5, 6]. The results show that there is a direct correlation between the calculated mantle potential temperature and the K/Ti ratio of Gale Crater rocks. This is consistent with fluid fluxed metasomatism introducing fluids to the system, which depressed the melting temperature and fluxed K but not Ti to the system. Therefore, all basalts at Gale Crater are consistent with forming from a metasomatized mantle source, which affected not only the chemistry of the basalts but also the formation conditions. References: [1] Cousin A. et al. (2017) Icarus. 288: 265-283. [2] Treiman A.H. et al. (2016) Journal of Geophysical Research: Planets. 121: 75-106. [3] Treiman A.H. and Medard E. (2016) Geological Society of America Abstracts with Programs. 48: doi: 10.1130/abs/2016AM-285851. [4] Schmidt M.E. et al. (2016) Geological Society of America Abstracts with Programs. 48: doi: 10

  16. Slab melting and magma formation beneath the southern Cascade arc

    Science.gov (United States)

    Walowski, Kristina J.; Wallace, Paul J.; Clynne, Michael A.; Rasmussen, D.J.; Weis, D.

    2016-01-01

    The processes that drive magma formation beneath the Cascade arc and other warm-slab subduction zones have been debated because young oceanic crust is predicted to largely dehydrate beneath the forearc during subduction. In addition, geochemical variability along strike in the Cascades has led to contrasting interpretations about the role of volatiles in magma generation. Here, we focus on the Lassen segment of the Cascade arc, where previous work has demonstrated across-arc geochemical variations related to subduction enrichment, and H-isotope data suggest that H2O in basaltic magmas is derived from the final breakdown of chlorite in the mantle portion of the slab. We use naturally glassy, olivine-hosted melt inclusions (MI) from the tephra deposits of eight primitive (MgO>7 wt%) basaltic cinder cones to quantify the pre-eruptive volatile contents of mantle-derived melts in this region. The melt inclusions have B concentrations and isotope ratios that are similar to mid-ocean ridge basalt (MORB), suggesting extensive dehydration of the downgoing plate prior to reaching sub-arc depths and little input of slab-derived B into the mantle wedge. However, correlations of volatile and trace element ratios (H2O/Ce, Cl/Nb, Sr/Nd) in the melt inclusions demonstrate that geochemical variability is the result of variable addition of a hydrous subduction component to the mantle wedge. Furthermore, correlations between subduction component tracers and radiogenic isotope ratios show that the subduction component has less radiogenic Sr and Pb than the Lassen sub-arc mantle, which can be explained by melting of subducted Gorda MORB beneath the arc. Agreement between pMELTS melting models and melt inclusion volatile, major, and trace element data suggests that hydrous slab melt addition to the mantle wedge can produce the range in primitive compositions erupted in the Lassen region. Our results provide further evidence that chlorite-derived fluids from the mantle portion of the

  17. Optimization of voltage output of energy harvesters with continuous mechanical rotation extracted from human motion (Conference Presentation)

    Science.gov (United States)

    Rashid, Evan; Hamidi, Armita; Tadesse, Yonas

    2017-04-01

    With increasing popularity of portable devices for outdoor activities, portable energy harvesting devices are coming into spot light. The next generation energy harvester which is called hybrid energy harvester can employ more than one mechanism in a single device to optimize portion of the energy that can be harvested from any source of waste energy namely motion, vibration, heat and etc. In spite of few recent attempts for creating hybrid portable devices, the level of output energy still needs to be improved with the intention of employing them in commercial electronic systems or further applications. Moreover, implementing a practical hybrid energy harvester in different application for further investigation is still challenging. This proposal is projected to incorporate a novel approach to maximize and optimize the voltage output of hybrid energy harvesters to achieve a greater conversion efficiency normalized by the total mass of the hybrid device than the simple arithmetic sum of the individual harvesting mechanisms. The energy harvester model previously proposed by Larkin and Tadesse [1] is used as a baseline and a continuous unidirectional rotation is incorporated to maximize and optimize the output. The device harvest mechanical energy from oscillatory motion and convert it to electrical energy through electromagnetic and piezoelectric systems. The new designed mechanism upgrades the device in a way that can harvest energy from both rotational and linear motions by using magnets. Likewise, the piezoelectric section optimized to harvest at least 10% more energy. To the end, the device scaled down for tested with different sources of vibrations in the immediate environment, including machinery operation, bicycle, door motion while opening and closing and finally, human motions. Comparing the results from literature proved that current device has capability to be employed in commercial small electronic devices for enhancement of battery usage or as a backup

  18. Increased eating control and energy levels associated with consumption of bitter orange (p-synephrine extract: a randomized placebo-controlled study

    Directory of Open Access Journals (Sweden)

    Kaats GR

    2017-07-01

    Full Text Available Gilbert R Kaats,1 Robert B Leckie,2 Nate Mrvichin,1 Sidney J Stohs3 1Integrative Health Technologies, Inc., 2R.B. Leckie Research Consultants, San Antonio, TX, 3Creighton University Medical Center, Omaha, NE, USA Abstract: Using a placebo-controlled double-blinded 30-day protocol, 40 overweight adults were asked to consume a chocolate-flavored chew 15–30 min before their two largest meals of the day. The chews contained either a placebo or an “active” product (100 mg of a bitter orange extract, standardized to 51.5 mg p-synephrine. Subjects completed a 13-item Weight Control Support Scale (WCSS containing eating control, energy level, and palatability subscales daily throughout the study. All 40 subjects completed the study. No adverse effects were reported in either the placebo or active groups. As compared to placebo, subjects consuming the active product reported statistically more (p≤0.001 positive responses on the WCSS as well as on each of the three subscales. This study suggests that, as compared to a placebo control, consuming a chew containing bitter orange extract (51.5 mg p-synephrine 15–30 min before the two largest meals of the day resulted in a statistically significant greater and more positive response to eating/appetite control and a weight-control support scale. Keywords: bitter orange extract, p-synephrine, Citrus aurantium, appetite suppression, energy, safety

  19. Experimental interaction of magma and “dirty” coolants

    Science.gov (United States)

    Schipper, C. Ian; White, James D. L.; Zimanowski, Bernd; Büttner, Ralf; Sonder, Ingo; Schmid, Andrea

    2011-03-01

    The presence of water at volcanic vents can have dramatic effects on fragmentation and eruption dynamics, but little is known about how the presence of particulate matter in external water will further alter eruptions. Volcanic edifices are inherently “dirty” places, where particulate matter of multiple origins and grainsizes typically abounds. We present the results of experiments designed to simulate non-explosive interactions between molten basalt and various “coolants,” ranging from homogeneous suspensions of 0 to 30 mass% bentonite clay in pure water, to heterogeneous and/or stratified suspensions including bentonite, sand, synthetic glass beads and/or naturally-sorted pumice. Four types of data are used to characterise the interactions: (1) visual/video observations; (2) grainsize and morphology of resulting particles; (3) heat-transfer data from a network of eight thermocouples; and (4) acoustic data from three force sensors. In homogeneous coolants with ~20% sediment, heat transfer is by forced convection and conduction, and thermal granulation is less efficient, resulting in fewer blocky particles, larger grainsizes, and weaker acoustic signals. Many particles are droplet-shaped or/and “vesicular,” containing bubbles filled with coolant. Both of these particle types indicate significant hydrodynamic magma-coolant mingling, and many of them are rewelded into compound particles. The addition of coarse material to heterogeneous suspensions further slows heat transfer thus reducing thermal granulation, and variable interlocking of large particles prevents efficient hydrodynamic mingling. This results primarily in rewelded melt piles and inefficient distribution of melt and heat throughout the coolant volume. Our results indicate that even modest concentrations of sediment in water will significantly limit heat transfer during non-explosive magma-water interactions. At high concentrations, the dramatic reduction in cooling efficiency and increase in

  20. Mechanisms of differentiation in the Skaergaard magma chamber

    Science.gov (United States)

    Tegner, C.; Lesher, C. E.; Holness, M. B.; Jakobsen, J. K.; Salmonsen, L. P.; Humphreys, M. C. S.; Thy, P.

    2012-04-01

    The Skaergaard intrusion is a superb natural laboratory for studying mechanisms of magma chamber differentiation. The magnificent exposures and new systematic sample sets of rocks that solidified inwards from the roof, walls and floor of the chamber provide means to test the relative roles of crystal settling, diffusion, convection, liquid immiscibility and compaction in different regions of the chamber and in opposite positions relative to gravity. Examination of the melt inclusions and interstitial pockets has demonstrated that a large portion of intrusion crystallized from an emulsified magma chamber composed of immiscible silica- and iron-rich melts. The similarity of ratios of elements with opposite partitioning between the immiscible melts (e.g. P and Rb) in wall, floor and roof rocks, however, indicate that large-scale separation did not occur. Yet, on a smaller scale of metres to hundred of metres and close to the interface between the roof and floor rocks (the Sandwich Horizon), irregular layers and pods of granophyre hosted by extremely iron-rich cumulates point to some separation of the two liquid phases. Similar proportions of the primocryst (cumulus) minerals in roof, wall and floor rocks indicate that crystal settling was not an important mechanism. Likewise, the lack of fractionation of elements with different behavior indicate that diffusion and fluid-driven metasomatism played relatively minor roles. Compositional convection and/or compaction within the solidifying crystal mush boundary layer are likely the most important mechanisms. A correlation of low trapped liquid fractions (calculated from strongly incompatible elements) in floor rocks with high fractionation density (the density difference between the crystal framework and the liquid) indicate that compaction is the dominating process in expelling evolved liquid from the crystal mush layer. This is supported by high and variable trapped liquid contents in the roof rocks, where gravity

  1. Eruption Depths, Magma Storage and Magma Degassing at Sumisu Caldera, Izu-Bonin Arc: Evidence from Glasses and Melt Inclusions

    Science.gov (United States)

    Johnson, E. R.

    2015-12-01

    Island arc volcanoes can become submarine during cataclysmal caldera collapse. The passage of a volcanic vent from atmospheric to under water environment involves complex modifications of the eruption style and subsequent transport of the pyroclasts. Here, we use FTIR measurements of the volatile contents of glass and melt inclusions in the juvenile pumice clasts in the Sumisu basin and its surroundings (Izu-Bonin arc) to investigate changes in eruption depths, magma storage and degassing over time. This study is based on legacy cores from ODP 126, where numerous unconsolidated (250 m), massive to normally graded pumice lapilli-tuffs were recovered over four cores (788C, 790A, 790B and 791A). Glass and clast geochemistry indicate the submarine Sumisu caldera as the source of several of these pumice lapilli-tuffs. Glass chips and melt inclusions from these samples were analyzed using FTIR for H2O and CO2 contents. Glass chips record variable H2O contents; most chips contain 0.6-1.6 wt% H2O, corresponding to eruption depths of 320-2100 mbsl. Variations in glass H2O and pressure estimates suggest that edifice collapse occurred prior-to or during eruption of the oldest of these samples, and that the edifice may have subsequently grown over time. Sanidine-hosted melt inclusions from two units record variably degassed but H2O-rich melts (1.1-5.6 wt% H2O). The lowest H2O contents overlap with glass chips, consistent with degassing and crystallization of melts until eruption, and the highest H2O contents suggest that large amounts of degassing accompanied likely explosive eruptions. Most inclusions, from both units, contain 2-4 wt% H2O, which further indicates that the magmas crystallized at pressures of ~50-100 MPa, or depths ~400-2800 m below the seafloor. Further glass and melt inclusion analyses, including major element compositions, will elucidate changes in magma storage, degassing and evolution over time.

  2. A Resource Assessment Of Geothermal Energy Resources For Converting Deep Gas Wells In Carbonate Strata Into Geothermal Extraction Wells: A Permian Basin Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Erdlac, Richard J., Jr.

    2006-10-12

    Previously conducted preliminary investigations within the deep Delaware and Val Verde sub-basins of the Permian Basin complex documented bottom hole temperatures from oil and gas wells that reach the 120-180C temperature range, and occasionally beyond. With large abundances of subsurface brine water, and known porosity and permeability, the deep carbonate strata of the region possess a good potential for future geothermal power development. This work was designed as a 3-year project to investigate a new, undeveloped geographic region for establishing geothermal energy production focused on electric power generation. Identifying optimum geologic and geographic sites for converting depleted deep gas wells and fields within a carbonate environment into geothermal energy extraction wells was part of the project goals. The importance of this work was to affect the three factors limiting the expansion of geothermal development: distribution, field size and accompanying resource availability, and cost. Historically, power production from geothermal energy has been relegated to shallow heat plumes near active volcanic or geyser activity, or in areas where volcanic rocks still retain heat from their formation. Thus geothermal development is spatially variable and site specific. Additionally, existing geothermal fields are only a few 10’s of square km in size, controlled by the extent of the heat plume and the availability of water for heat movement. This plume radiates heat both vertically as well as laterally into the enclosing country rock. Heat withdrawal at too rapid a rate eventually results in a decrease in electrical power generation as the thermal energy is “mined”. The depletion rate of subsurface heat directly controls the lifetime of geothermal energy production. Finally, the cost of developing deep (greater than 4 km) reservoirs of geothermal energy is perceived as being too costly to justify corporate investment. Thus further development opportunities

  3. Magma transfer at Campi Flegrei caldera (Italy) before the 1538 AD eruption.

    Science.gov (United States)

    Di Vito, Mauro A; Acocella, Valerio; Aiello, Giuseppe; Barra, Diana; Battaglia, Maurizio; Carandente, Antonio; Del Gaudio, Carlo; de Vita, Sandro; Ricciardi, Giovanni P; Ricco, Ciro; Scandone, Roberto; Terrasi, Filippo

    2016-08-25

    Calderas are collapse structures related to the emptying of magmatic reservoirs, often associated with large eruptions from long-lived magmatic systems. Understanding how magma is transferred from a magma reservoir to the surface before eruptions is a major challenge. Here we exploit the historical, archaeological and geological record of Campi Flegrei caldera to estimate the surface deformation preceding the Monte Nuovo eruption and investigate the shallow magma transfer. Our data suggest a progressive magma accumulation from ~1251 to 1536 in a 4.6 ± 0.9 km deep source below the caldera centre, and its transfer, between 1536 and 1538, to a 3.8 ± 0.6 km deep magmatic source ~4 km NW of the caldera centre, below Monte Nuovo; this peripheral source fed the eruption through a shallower source, 0.4 ± 0.3 km deep. This is the first reconstruction of pre-eruptive magma transfer at Campi Flegrei and corroborates the existence of a stationary oblate source, below the caldera centre, that has been feeding lateral eruptions for the last ~5 ka. Our results suggest: 1) repeated emplacement of magma through intrusions below the caldera centre; 2) occasional lateral transfer of magma feeding non-central eruptions within the caldera. Comparison with historical unrest at calderas worldwide suggests that this behavior is common.

  4. Reconstructing modalities of magma storage in the crust by thermo-rheological modelling

    Science.gov (United States)

    Caricchi, L.; Annen, C.; Rust, A.; Blundy, J.

    2012-04-01

    During my PhD I worked under the supervision of Luigi Burlini studying the rheological behaviour of magma. Luigi was not only a great teacher and friend but he was also able to project the science he was performing beyond the obvious applications. This aspect of Luigi's approach shaped my approach to research and brought me to think to ways of applying the studies we performed together to unravel the complexity of nature that impassioned and inspired him. This contribution comes from the motivation and interest that Luigi created in me during the short, but truly memorable journey we shared together. This study combines petrology, thermal modelling and magma rheology to characterise timescales and modalities of magma emplacement in the Earth's crust. Thermal modelling was performed to determine the influence of magma injection rates in the crust on the temperature evolution of a magmatic body. The injected tonalitic magma was considered to contain dioritic enclaves, common in plutons. The contrast in chemical composition between host and enclaves leads to different crystallinities of these magmas during cooling and produce a rheological contrast that permits reciprocal deformation only in restricted temperature ranges. Characterising the thermal and rheological evolution of host magma and enclaves, we traced the evolution of strain recorded by these inclusions during the construction of an intrusion, showing that the strain recorded by enclaves distributed in different portions of a pluton can be used to constrain thermal evolution in time, magmatic fluxes and timescale of assemblage of magmatic bodies in the crust.

  5. Magma buoyancy and volatile ascent driving autocyclic eruptivity at Hekla Volcano (Iceland)

    Science.gov (United States)

    Hautmann, Stefanie; Sacks, I. Selwyn; Linde, Alan T.; Roberts, Matthew J.

    2017-09-01

    Volcanic eruptions are typically accompanied by ground deflation due to the withdrawal of magma from depth and its effusion at the surface. Here, based on continuous high-resolution borehole strain data, we show that ground deformation was absent during the major effusion phases of the 1991 and 2000 eruptions of Hekla Volcano, Iceland. This lack of surface deformation challenges the classic model of magma intrusion/withdrawal as source for volcanic ground uplift/subsidence. We incorporate geodetic and geochemical observables into theoretical models of magma chamber dynamics in order to constrain quantitatively alternative co- and intereruptive physical mechanisms that govern magma propagation and system pressurization. We find the lack of surface deformation during lava effusion to be linked to chamber replenishment from below whilst magma migrates as a buoyancy-driven flow from the magma chamber towards the surface. We further demonstrate that intereruptive pressure build-up is likely to be generated by volatile ascent within the chamber rather than magma injection. Our model explains the persistent periodic eruptivity at Hekla throughout historic times with self-initiating cycles and is conceptually relevant to other volcanic systems.

  6. Locating the depth of magma supply for volcanic eruptions, insights from Mt. Cameroon.

    Science.gov (United States)

    Geiger, Harri; Barker, Abigail K; Troll, Valentin R

    2016-10-07

    Mt. Cameroon is one of the most active volcanoes in Africa and poses a possible threat to about half a million people in the area, yet knowledge of the volcano's underlying magma supply system is sparse. To characterize Mt. Cameroon's magma plumbing system, we employed mineral-melt equilibrium thermobarometry on the products of the volcano's two most recent eruptions of 1999 and 2000. Our results suggest pre-eruptive magma storage between 20 and 39 km beneath Mt. Cameroon, which corresponds to the Moho level and below. Additionally, the 1999 eruption products reveal several shallow magma pockets between 3 and 12 km depth, which are not detected in the 2000 lavas. This implies that small-volume magma batches actively migrate through the plumbing system during repose intervals. Evolving and migrating magma parcels potentially cause temporary unrest and short-lived explosive outbursts, and may be remobilized during major eruptions that are fed from sub-Moho magma reservoirs.

  7. Degassing during quiescence as a trigger of magma ascent and volcanic eruptions.

    Science.gov (United States)

    Girona, Társilo; Costa, Fidel; Schubert, Gerald

    2015-12-15

    Understanding the mechanisms that control the start-up of volcanic unrest is crucial to improve the forecasting of eruptions at active volcanoes. Among the most active volcanoes in the world are the so-called persistently degassing ones (e.g., Etna, Italy; Merapi, Indonesia), which emit massive amounts of gas during quiescence (several kilotonnes per day) and erupt every few months or years. The hyperactivity of these volcanoes results from frequent pressurizations of the shallow magma plumbing system, which in most cases are thought to occur by the ascent of magma from deep to shallow reservoirs. However, the driving force that causes magma ascent from depth remains unknown. Here we demonstrate that magma ascent can be triggered by the passive release of gas during quiescence, which induces the opening of pathways connecting deep and shallow magma reservoirs. This top-down mechanism for volcanic eruptions contrasts with the more common bottom-up mechanisms in which magma ascent is only driven by processes occurring at depth. A cause-effect relationship between passive degassing and magma ascent can explain the fact that repose times are typically much longer than unrest times preceding eruptions, and may account for the so frequent unrest episodes of persistently degassing volcanoes.

  8. Drilling into Rhyolitic Magma at Shallow depth at Krafla Volcanic Complex, NE-Iceland

    Science.gov (United States)

    Mortensen, A. K.; Markússon, S. H.; Gudmundsson, Á.; Pálsson, B.

    2017-12-01

    Krafla volcanic complex in NE-Iceland is an active volcano but the latest eruption was the Krafla Fires in 1975-1984. Though recent volcanic activity has consisted of basaltic fissure eruptions, then it is rhyolitic magma that has been intercepted on at least two occasions while drilling geothermal production wells in the geothermal field suggesting a layered magma plumbing system beneath the Krafla volcanic complex. In 2008 quenched rhyolitic glass was retrieved from the bottom of well KJ-39, which is 2865 m deep ( 2571 m true vertical depth). In 2009 magma was again encountered at an even shallower depth and in more than 2,5 km distance from the bottom of well KJ-39, but in 2009 well IDDP-1 was drilled into magma three times just below 2100 m depth. Only on the last occasion was quenched glass retrieved to confirm that magma had been encountered. In well KJ-39 the quenched glass was rhyolitic in composition. The glass contained resorbed minerals of plagioclase, clinopyroxene and titanomagnetite, but the composition of the glass resembles magma that has formed by partial melting of hydrated basalt. The melt was encountered among cuttings from impermeable, coarse basaltic intrusives at a depth, where the well was anticipated to penetrate the Hólseldar volcanic fissure. In IDDP-1 the quenched glass was also rhyolitic in composition. The glass contained less than 5% of phenocrysts, but the phenocryst assemblage included andesine plagioclase, augite, pigeonite, and titanomagnetite. At IDDP-1 the melt was encountered below a permeable zone composed of fine to coarse grained felsite and granophyre. The disclosure of magma in two wells at Krafla volcanic complex verify that rhyolitic magma can be encountered at shallow depth across a larger area within the caldera. The encounter of magma at shallow depth conforms with that superheated conditions have been found at >2000 m depth in large parts of Krafla geothermal field.

  9. The parent magma of the Nakhla (SNC) meteorite: Reconciliation of composition estimates from magmatic inclusions and element partitioning

    Science.gov (United States)

    Treiman, A. H.

    1993-01-01

    The composition of the parent magma of the Nakhla meteorite was difficult to determine, because it is accumulate rock, enriched in olivine and augite relative to a basalt magma. A parent magma composition is estimated from electron microprobe area analyses of magmatic inclusions in olivine. This composition is consistent with an independent estimate based on the same inclusions, and with chemical equilibria with the cores of Nakhla's augites. This composition reconciles most of the previous estimates of Nakhla's magma composition, and obviates the need for complex magmatic processes. Inconsistency between this composition and those calculated previously suggests that magma flowed through and crystallized into Nakhla as it cooled.

  10. The parent magma of xenoliths in shergottite EETA79001: Bulk and trace element composition inferred from magmatic inclusions

    Science.gov (United States)

    Treiman, Allan H.; Lindstrom, David J.; Martinez, Rene R.

    1994-01-01

    The SNC meteorites are samples of the Martian crust, so inferences about their origins and parent magmas are of wide planetologic significance. The EETA79001 shergottite, a basalt, contains xenoliths of pyroxene-olivine cumulate rocks which are possibly related to the ALHA77005 and LEW88516 SNC lherzolites. Olivines in the xenoliths contain magmatic inclusions, relics of magma trapped within the growing crystals. The magmatic inclusions allow a parent magma composition to be retrieved; it is similar to the composition reconstructed from xenolith pyroxenes by element distribution coefficients. The xenolith parent magma is similar but not identical to parent magmas for the shergottite lherzolites.

  11. The 2006-2009 activity of the Ubinas volcano (Peru): Petrology of the 2006 eruptive products and insights into genesis of andesite magmas, magma recharge and plumbing system

    Science.gov (United States)

    Rivera, Marco; Thouret, Jean-Claude; Samaniego, Pablo; Le Pennec, Jean-Luc

    2014-01-01

    Following a fumarolic episode that started six months earlier, the most recent eruptive activity of the Ubinas volcano (south Peru) began on 27 March 2006, intensified between April and October 2006 and slowly declined until December 2009. The chronology of the explosive episode and the extent and composition of the erupted material are documented with an emphasis on ballistic ejecta. A petrological study of the juvenile products allows us to infer the magmatic processes related to the 2006-2009 eruptions of the andesitic Ubinas volcano. The juvenile magma erupted during the 2006 activity shows a homogeneous bulk-rock andesitic composition (56.7-57.6 wt.% SiO2), which belongs to a medium- to high-K calc-alkaline series. The mineral assemblage of the ballistic blocks and tephra consists of plagioclase > two-pyroxenes > Fe-Ti oxide and rare olivine and amphibole set in a groundmass of the same minerals with a dacitic composition (66-67 wt.% SiO2). Thermo-barometric data, based on two-pyroxene and amphibole stability, records a magma temperature of 998 ± 14 °C and a pressure of 476 ± 36 MPa. Widespread mineralogical and textural features point to a disequilibrium process in the erupted andesite magma. These features include inversely zoned "sieve textures" in plagioclase, inversely zoned clinopyroxene, and olivine crystals with reaction and thin overgrowth rims. They indicate that the pre-eruptive magmatic processes were dominated by recharge of a hotter mafic magma into a shallow reservoir, where magma mingling occurred and triggered the eruption. Prior to 2006, a probable recharge of a mafic magma produced strong convection and partial homogenization in the reservoir, as well as a pressure increase and higher magma ascent rate after four years of fumarolic activity. Mafic magmas do not prevail in the Ubinas pre-historical lavas and tephras. However, mafic andesites have been erupted during historical times (e.g. AD 1667 and 2006-2009 vulcanian eruptions). Hence

  12. A dynamic balance between magma supply and eruption rate at Kilauea volcano, Hawaii

    Science.gov (United States)

    Denlinger, R.P.

    1997-01-01

    The dynamic balance between magma supply and vent output at Kilauea volcano is used to estimate both the volume of magma stored within Kilauea volcano and its magma supply rate. Throughout most of 1991 a linear decline in volume flux from the Kupaianaha vent on Kilauea's east rift zone was associated with a parabolic variation in the elevation of Kilauea's summit as vent output initially exceeded then lagged behind the magma supply to the volcano. The correspondence between summit elevation and tilt established with over 30 years of data provided daily estimates of summit elevation in terms of summit tilt. The minimum in the parabolic variation in summit tilt and elevation (or zero elevation change) occurs when the magma supply to the reservoir from below the volcano equals the magma output from the reservoir to the surface, so that the magma supply rate is given by vent flux on that day. The measurements of vent flux and tilt establish that the magma supply rate to Kilauea volcano on June 19, 1991, was 217,000 ?? 10,000 m3/d (or 0.079 ?? 0.004 km3/yr). This is close to the average eruptive rate of 0.08 km3/yr between 1958 and 1984. In addition, the predictable response of summit elevation and tilt to each east rift zone eruption near Puu Oo since 1983 shows that summit deformation is also a measure of magma reservoir pressure. Given this, the correlation between the elevation of the Puu Oo lava lake (4 km uprift of Kupaianaha and 18 km from the summit) and summit tilt provides an estimate for magma pressure changes corresponding to summit tilt changes. The ratio of the change in volume to the change in reservoir pressure (dV/dP) during vent activity may be determined by dividing the ratio of volume erupted to change in summit tilt (dV/dtilt) by the ratio of pressure change to change in summit tilt (dP/dtilt). This measure of dV/dP, when combined with laboratory measurements of the bulk modulus of tholeitic melt, provides an estimate of 240 ?? 50 km3 for the volume

  13. Enhancement of eruption explosivity by heterogeneous bubble nucleation triggered by magma mingling.

    Science.gov (United States)

    Paredes-Mariño, Joali; Dobson, Katherine J; Ortenzi, Gianluigi; Kueppers, Ulrich; Morgavi, Daniele; Petrelli, Maurizio; Hess, Kai-Uwe; Laeger, Kathrin; Porreca, Massimiliano; Pimentel, Adriano; Perugini, Diego

    2017-12-04

    We present new evidence that shows magma mingling can be a key process during highly explosive eruptions. Using fractal analysis of the size distribution of trachybasaltic fragments found on the inner walls of bubbles in trachytic pumices, we show that the more mafic component underwent fracturing during quenching against the trachyte. We propose a new mechanism for how this magmatic interaction at depth triggered rapid heterogeneous bubble nucleation and growth and could have enhanced eruption explosivity. We argue that the data support a further, and hitherto unreported contribution of magma mingling to highly explosive eruptions. This has implications for hazard assessment for those volcanoes in which evidence of magma mingling exists.

  14. Redox systematics of a magma ocean with variable pressure-temperature gradients and composition.

    Science.gov (United States)

    Righter, K; Ghiorso, M S

    2012-07-24

    Oxygen fugacity in metal-bearing systems controls some fundamental aspects of the geochemistry of the early Earth, such as the FeO and siderophile trace element content of the mantle, volatile species that influence atmospheric composition, and conditions for organic compounds synthesis. Redox and metal-silicate equilibria in the early Earth are sensitive to oxygen fugacity (fO(2)), yet are poorly constrained in modeling and experimentation. High pressure and temperature experimentation and modeling in metal-silicate systems usually employs an approximation approach for estimating fO(2) that is based on the ratio of Fe and FeO [called "ΔIW (ratio)" hereafter]. We present a new approach that utilizes free energy and activity modeling of the equilibrium: Fe + SiO(2) + O(2) = Fe(2)SiO(4) to calculate absolute fO(2) and relative to the iron-wüstite (IW) buffer at pressure and temperature [ΔIW (P,T)]. This equilibrium is considered across a wide range of pressures and temperatures, including up to the liquidus temperature of peridotite (4,000 K at 50 GPa). Application of ΔIW (ratio) to metal-silicate experiments can be three or four orders of magnitude different from ΔIW (P,T) values calculated using free energy and activity modeling. We will also use this approach to consider the variation in oxygen fugacity in a magma ocean scenario for various thermal structures for the early Earth: hot liquidus gradient, 100 °C below the liquidus, hot and cool adiabatic gradients, and a cool subsolidus adiabat. The results are used to assess the effect of increasing P and T, changing silicate composition during accretion, and related to current models for accretion and core formation in the Earth. The fO(2) in a deep magma ocean scenario may become lower relative to the IW buffer at hotter and deeper conditions, which could include metal entrainment scenarios. Therefore, fO(2) may evolve from high to low fO(2) during Earth (and other differentiated bodies) accretion. Any

  15. Energy

    International Nuclear Information System (INIS)

    Meister, F.; Ott, F.

    2002-01-01

    This chapter gives an overview of the current energy economy in Austria. The Austrian political aims of sustainable development and climate protection imply a reorientation of the Austrian energy policy as a whole. Energy consumption trends (1993-1998), final energy consumption by energy carrier (indexed data 1993-1999), comparative analysis of useful energy demand (1993 and 1999) and final energy consumption of renewable energy sources by sector (1996-1999) in Austria are given. The necessary measures to be taken in order to reduce the energy demand and increased the use of renewable energy are briefly mentioned. Figs. 5. (nevyjel)

  16. Effects of a natural extract from Mangifera indica L, and its active compound, mangiferin, on energy state and lipid peroxidation of red blood cells.

    Science.gov (United States)

    Rodríguez, Janet; Di Pierro, Donato; Gioia, Magda; Monaco, Susanna; Delgado, René; Coletta, Massimiliano; Marini, Stefano

    2006-09-01

    Following oxidative stress, modifications of several biologically important macromolecules have been demonstrated. In this study we investigated the effect of a natural extract from Mangifera indica L (Vimang), its main ingredient mangiferin and epigallocatechin gallate (EGCG) on energy metabolism, energy state and malondialdehyde (MDA) production in a red blood cell system. Analysis of MDA, high energy phosphates and ascorbate was carried out by high performance liquid chromatography (HPLC). Under the experimental conditions, concentrations of MDA and ATP catabolites were affected in a dose-dependent way by H2O2. Incubation with Vimang (0.1, 1, 10, 50 and 100 microg/mL), mangiferin (1, 10, 100 microg/mL) and EGCG (0.01, 0.1, 1, 10 microM) significantly enhances erythrocyte resistance to H2O2-induced reactive oxygen species production. In particular, we demonstrate the protective activity of these compounds on ATP, GTP and total nucleotides (NT) depletion after H2O2-induced damage and a reduction of NAD and ADP, which both increase because of the energy consumption following H2O2 addition. Energy charge potential, decreased in H2O2-treated erythrocytes, was also restored in a dose-dependent way by these substances. Their protective effects might be related to the strong free radical scavenging ability described for polyphenols.

  17. Energy

    International Nuclear Information System (INIS)

    Meister, F.

    2001-01-01

    This chapter of the environmental control report deals with the environmental impact of energy production, energy conversion, atomic energy and renewable energy. The development of the energy consumption in Austria for the years 1993 to 1999 is given for the different energy types. The development of the use of renewable energy sources in Austria is given, different domestic heat-systems are compared, life cycles and environmental balance are outlined. (a.n.)

  18. Volatile element loss during planetary magma ocean phases

    Science.gov (United States)

    Dhaliwal, Jasmeet K.; Day, James M. D.; Moynier, Frédéric

    2018-01-01

    Moderately volatile elements (MVE) are key tracers of volatile depletion in planetary bodies. Zinc is an especially useful MVE because of its generally elevated abundances in planetary basalts, relative to other MVE, and limited evidence for mass-dependent isotopic fractionation under high-temperature igneous processes. Compared with terrestrial basalts, which have δ66Zn values (per mille deviation of the 66Zn/64Zn ratio from the JMC-Lyon standard) similar to some chondrite meteorites (∼+0.3‰), lunar mare basalts yield a mean δ66Zn value of +1.4 ± 0.5‰ (2 st. dev.). Furthermore, mare basalts have average Zn concentrations ∼50 times lower than in typical terrestrial basaltic rocks. Late-stage lunar magmatic products, including ferroan anorthosite, Mg- and Alkali-suite rocks have even higher δ66Zn values (+3 to +6‰). Differences in Zn abundance and isotopic compositions between lunar and terrestrial rocks have previously been interpreted to reflect evaporative loss of Zn, either during the Earth-Moon forming Giant Impact, or in a lunar magma ocean (LMO) phase. To explore the mechanisms and processes under which volatile element loss may have occurred during a LMO phase, we developed models of Zn isotopic fractionation that are generally applicable to planetary magma oceans. Our objective was to identify conditions that would yield a δ66Zn signature of ∼+1.4‰ within the lunar mantle. For the sake of simplicity, we neglect possible Zn isotopic fractionation during the Giant Impact, and assumed a starting composition equal to the composition of the present-day terrestrial mantle, assuming both the Earth and Moon had zinc 'consanguinity' following their formation. We developed two models: the first simulates evaporative fractionation of Zn only prior to LMO mixing and crystallization; the second simulates continued evaporative fractionation of Zn that persists until ∼75% LMO crystallization. The first model yields a relatively homogenous bulk solid

  19. Symmetry energy, its density slope, and neutron-proton effective mass splitting at normal density extracted from global nucleon optical potentials

    International Nuclear Information System (INIS)

    Xu Chang; Li Baoan; Chen Liewen

    2010-01-01

    Based on the Hugenholtz-Van Hove theorem, it is shown that both the symmetry energy E sym (ρ) and its density slope L(ρ) at normal density ρ 0 are completely determined by the nucleon global optical potentials. The latter can be extracted directly from nucleon-nucleus scatterings, (p,n) charge-exchange reactions, and single-particle energy levels of bound states. Averaging all phenomenological isovector nucleon potentials constrained by world data available in the literature since 1969, the best estimates of E sym (ρ 0 )=31.3 MeV and L(ρ 0 )=52.7 MeV are simultaneously obtained. Moreover, the corresponding neutron-proton effective mass splitting in neutron-rich matter of isospin asymmetry δ is estimated to be (m n * -m p * )/m=0.32δ.

  20. Energy optimization and comparative study of pre- and post-fractionator extractive dividing wall column for the CO2–ethane azeotropic process

    International Nuclear Information System (INIS)

    Tavan, Yadollah; Riazi, Seiied Hadi; Nozohouri, Mostafa

    2014-01-01

    Graphical abstract: - Highlights: • Two arrangements is proposed for extractive DWC based on pre- and post- fractionator. • Operating parameters are optimized to minimize energy demand. • The pre-fractionator design showed the best performance in comparison to others. - Abstract: Two possible extractive dividing-wall column (DWC) arrangements are explored to find the potential benefits derived from thermally coupled distillations in separation of a mixture including the CO 2 –ethane azeotrope with a low boiling point. It is shown that the process including pre-fractionator in the DWC design in its optimized state leads to 51.6% reduction in total duties in comparison with the conventional process. Furthermore, a comparison between conventional extractive distillation columns and the new DWC process is made in terms of cost estimation, CO 2 removal efficiency and CO 2 emission reduction. Remarkable, the results clearly show that DWC process is interesting/feasible and the novel proposed DWC alternative reduces the steam requirements by 41% and the equipment costs by 31%

  1. NVP melt/magma viscosity: insight on Mercury lava flows

    Science.gov (United States)

    Rossi, Stefano; Morgavi, Daniele; Namur, Olivier; Vetere, Francesco; Perugini, Diego; Mancinelli, Paolo; Pauselli, Cristina

    2016-04-01

    After more than four years of orbiting Mercury, NASA's MESSENGER spacecraft came to an end in late April 2015. MESSENGER has provided many new and surprising results. This session will again highlight the latest results on Mercury based on MESSENGER observations or updated modelling. The session will further address instrument calibration and science performance both retrospective on MESSENGER and on the ESA/JAXA BepiColombo mission. Papers covering additional themes related to Mercury are also welcomed. Please be aware that this session will be held as a PICO session. This will allow an intensive exchange of expertise and experience between the individual instruments and mission. NVP melt/magma viscosity: insight on Mercury lava flows S. Rossi1, D. Morgavi1, O. Namur2, D. Perugini1, F.Vetere1, P. Mancinelli1 and C. Pauselli1 1 Dipartimento di Fisica e Geologia, Università di Perugia, piazza Università 1, 06123 Perugia, Italy 2 Uni Hannover Institut für Mineralogie, Leibniz Universität Hannover, Callinstraβe 3, 30167 Hannover, Germany In this contribution we report new measurements of viscosity of synthetic komatitic melts, used the behaviour of silicate melts erupted at the surface of Mercury. Composition of Mercurian surface magmas was calculated using the most recent maps produced from MESSENGER XRS data (Weider et al., 2015). We focused on the northern hemisphere (Northern Volcanic Province, NVP, the largest lava flow on Mercury and possibly in the Solar System) for which the spatial resolution of MESSENGER measurements is high and individual maps of Mg/Si, Ca/Si, Al/Si and S/Si were combined. The experimental starting material contains high Na2O content (≈7 wt.%) that strongly influences viscosity. High temperature viscosity measurements were carried out at 1 atm using a concentric cylinder apparatus equipped with an Anton Paar RheolabQC viscometer head at the Department of Physics and Geology (PVRG_lab) at the University of Perugia (Perugia, Italy

  2. Barium isotope geochemistry of subduction-zone magmas

    Science.gov (United States)

    Yu, H.; Nan, X.; Huang, J.; Wörner, G.; Huang, F.

    2017-12-01

    Subduction zones are crucial tectonic setting to study material exchange between crust and mantle, mantle partial melting with fluid addition, and formation of ore-deposits1-3. The geochemical characteristics of arc lavas from subduction zones are different from magmas erupted at mid-ocean ridges4, because there are addition of fluids/melts from subducted AOC and its overlying sediments into their source regions in the sub-arc mantle4. Ba is highly incompatible during mantle melting5, and it is enriched in crust (456 ppm)6 relative to the mantle (7.0 ppm)7. The subducted sediments are also enriched in Ba (776 ppm of GLOSS)8. Moreover, because Ba is fluid soluble during subduction, it has been used to track contributions of subduction-related fluids to arc magmas9 or recycled sediments to the mantle10-11. To study the Ba isotope fractionation behavior during subduction process, we analyzed well-characterized, chemically-diverse arc lavas from Central American, Kamchatka, Central-Eastern Aleutian, and Southern Lesser Antilles. The δ137/134Ba of Central American arc lavas range from -0.13 to 0.24‰, and have larger variation than the arc samples from other locations. Except one sample from Central-Eastern Aleutian arc with obviously heavy δ137/134Ba values (0.27‰), all other samples from Kamchatka, Central-Eastern Aleutian, Southern Lesser Antilles arcs are within the range of OIB. The δ137/134Ba is not correlated with the distance to trench, partial melting degrees (Mg#), or subducting slab-derived components. The samples enriched with heavy Ba isotopes have low Ba contents, indicating that Ba isotopes can be fractionated at the beginning of dehydration process with small amount of Ba releasing to the mantle wedge. With the dehydration degree increasing, more Ba of the subducted slab can be added to the source of arc lavas, likely homogenizing the Ba isotope signatures. 1. Rudnick, R., 1995 Nature; 2. Tatsumi, Y. & Kogiso, T., 2003; 3. Sun, W., et al., 2015 Ore

  3. From Extraction of Local Structures of Protein Energy Landscapes to Improved Decoy Selection in Template-Free Protein Structure Prediction.

    Science.gov (United States)

    Akhter, Nasrin; Shehu, Amarda

    2018-01-19

    Due to the essential role that the three-dimensional conformation of a protein plays in regulating interactions with molecular partners, wet and dry laboratories seek biologically-active conformations of a protein to decode its function. Computational approaches are gaining prominence due to the labor and cost demands of wet laboratory investigations. Template-free methods can now compute thousands of conformations known as decoys, but selecting native conformations from the generated decoys remains challenging. Repeatedly, research has shown that the protein energy functions whose minima are sought in the generation of decoys are unreliable indicators of nativeness. The prevalent approach ignores energy altogether and clusters decoys by conformational similarity. Complementary recent efforts design protein-specific scoring functions or train machine learning models on labeled decoys. In this paper, we show that an informative consideration of energy can be carried out under the energy landscape view. Specifically, we leverage local structures known as basins in the energy landscape probed by a template-free method. We propose and compare various strategies of basin-based decoy selection that we demonstrate are superior to clustering-based strategies. The presented results point to further directions of research for improving decoy selection, including the ability to properly consider the multiplicity of native conformations of proteins.

  4. From Extraction of Local Structures of Protein Energy Landscapes to Improved Decoy Selection in Template-Free Protein Structure Prediction

    Directory of Open Access Journals (Sweden)

    Nasrin Akhter

    2018-01-01

    Full Text Available Due to the essential role that the three-dimensional conformation of a protein plays in regulating interactions with molecular partners, wet and dry laboratories seek biologically-active conformations of a protein to decode its function. Computational approaches are gaining prominence due to the labor and cost demands of wet laboratory investigations. Template-free methods can now compute thousands of conformations known as decoys, but selecting native conformations from the generated decoys remains challenging. Repeatedly, research has shown that the protein energy functions whose minima are sought in the generation of decoys are unreliable indicators of nativeness. The prevalent approach ignores energy altogether and clusters decoys by conformational similarity. Complementary recent efforts design protein-specific scoring functions or train machine learning models on labeled decoys. In this paper, we show that an informative consideration of energy can be carried out under the energy landscape view. Specifically, we leverage local structures known as basins in the energy landscape probed by a template-free method. We propose and compare various strategies of basin-based decoy selection that we demonstrate are superior to clustering-based strategies. The presented results point to further directions of research for improving decoy selection, including the ability to properly consider the multiplicity of native conformations of proteins.

  5. EquiMar : Equitable Testing and Evaluation of Marine Energy Extraction Devices in Terms of Performance, Cost and Environmental Impact

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Pecher, Arthur; Margheritini, Lucia

    The Sea Trial Manual (D4.1) describes the type of operations required to advance an ocean energy conversion device (wave and tide) from an intermediate scaled sub-systems proving machine (circa 1:4) to a full size solo prototype pre-production unit and on towards a pre-commercial device ready for...... of marine energy converters, according to Annex 1 – Description of Work of the EquiMar project, where task 4.2 is defined. Some slight modifications have been made to the original structure due to re-adjustments in accordance with the on-going research.......The Sea Trial Manual (D4.1) describes the type of operations required to advance an ocean energy conversion device (wave and tide) from an intermediate scaled sub-systems proving machine (circa 1:4) to a full size solo prototype pre-production unit and on towards a pre-commercial device ready...

  6. EquiMar : Equitable Testing and Evaluation of Marine Energy Extraction Devices in terms of Performance, Cost and Environmental Impact

    DEFF Research Database (Denmark)

    McCombes, T; Johnstone, C.; Holmes, B.

    At present no common practices are adopted to assess the performance and operational characteristics of conceptual and small prototype wave and tidal energy devices when tested within controlled laboratory environments. Information acquired from this early stage assessment may be used to secure...... development funding or promote a specific wave or tidal energy device. Since no standards exist, the data produced may be misinterpreted or inaccurately presented, which in turn may lead to failure to live up to performance expectations, as devices scale up in size. This report aims to identify limitations...

  7. EquiMar : Equitable Testing and Evaluation of Marine Energy Extraction Devices in terms of Performance, Cost and Environmental Impact

    DEFF Research Database (Denmark)

    McCombes, T; Johnstone, C.; Holmes, B.

    At present no common practices are adopted to assess the performance and operational characteristics of conceptual and small prototype wave and tidal energy devices when tested within controlled laboratory environments. Information acquired from this early stage assessment may be used to secure...... development funding or promote a specific wave or tidal energy device. Since no standards exist, the data produced may be misinterpreted or inaccurately presented, which in turn may lead to failure to live up to performance expectations, as devices scale up in size. This report builds on Deliverable 3.3 which...

  8. Magma degassing triggered by static decompression at Kīlauea Volcano, Hawai‘i

    Science.gov (United States)

    Poland, Michael P.; Jeff, Sutton A.; Gerlach, Terrence M.

    2009-01-01

    During mid-June 2007, the summit of Kīlauea Volcano, Hawai‘i, deflated rapidly as magma drained from the subsurface to feed an east rift zone intrusion and eruption. Coincident with the deflation, summit SO2 emission rates rose by a factor of four before decaying to background levels over several weeks. We propose that SO2 release was triggered by static decompression caused by magma withdrawal from Kīlauea's shallow summit reservoir. Models of the deflation suggest a pressure drop of 0.5–3 MPa, which is sufficient to trigger exsolution of the observed excess SO2 from a relatively small volume of magma at the modeled source depth beneath Kīlauea's summit. Static decompression may also explain other episodes of deflation accompanied by heightened gas emission, including the precursory phases of Kīlauea's 2008 summit eruption. Hazards associated with unexpected volcanic gas emission argue for increased awareness of magma reservoir pressure fluctuations.

  9. A basal magma ocean dynamo to explain the early lunar magnetic field

    Science.gov (United States)

    Scheinberg, Aaron L.; Soderlund, Krista M.; Elkins-Tanton, Linda T.

    2018-06-01

    The source of the ancient lunar magnetic field is an unsolved problem in the Moon's evolution. Theoretical work invoking a core dynamo has been unable to explain the magnitude of the observed field, falling instead one to two orders of magnitude below it. Since surface magnetic field strength is highly sensitive to the depth and size of the dynamo region, we instead hypothesize that the early lunar dynamo was driven by convection in a basal magma ocean formed from the final stages of an early lunar magma ocean; this material is expected to be dense, radioactive, and metalliferous. Here we use numerical convection models to predict the longevity and heat flow of such a basal magma ocean and use scaling laws to estimate the resulting magnetic field strength. We show that, if sufficiently electrically conducting, a magma ocean could have produced an early dynamo with surface fields consistent with the paleomagnetic observations.

  10. The Lunar Magma Ocean (LMO) Paradigm Versus the Realities of Lunar Anorthosites

    Science.gov (United States)

    Treiman, A. H.; Gross, J.

    2018-05-01

    The paradigm of the Lunar Magma Ocean (LMO) is inconsistent with much chemical and compositional data on lunar anorthosites. The paradigm of serial anorthosite diapirism is more consistent, though not a panacea.

  11. Magma flow instability and cyclic activity at soufriere hills volcano, montserrat, british west indies

    Science.gov (United States)

    Voight; Sparks; Miller; Stewart; Hoblitt; Clarke; Ewart; Aspinall; Baptie; Calder; Cole; Druitt; Hartford; Herd; Jackson; Lejeune; Lockhart; Loughlin; Luckett; Lynch; Norton; Robertson; Watson; Watts; Young

    1999-02-19

    Dome growth at the Soufriere Hills volcano (1996 to 1998) was frequently accompanied by repetitive cycles of earthquakes, ground deformation, degassing, and explosive eruptions. The cycles reflected unsteady conduit flow of volatile-charged magma resulting from gas exsolution, rheological stiffening, and pressurization. The cycles, over hours to days, initiated when degassed stiff magma retarded flow in the upper conduit. Conduit pressure built with gas exsolution, causing shallow seismicity and edifice inflation. Magma and gas were then expelled and the edifice deflated. The repeat time-scale is controlled by magma ascent rates, degassing, and microlite crystallization kinetics. Cyclic behavior allows short-term forecasting of timing, and of eruption style related to explosivity potential.

  12. Role of syn-eruptive plagioclase disequilibrium crystallization in basaltic magma ascent dynamics.

    Science.gov (United States)

    La Spina, G; Burton, M; De' Michieli Vitturi, M; Arzilli, F

    2016-12-12

    Timescales of magma ascent in conduit models are typically assumed to be much longer than crystallization and gas exsolution for basaltic eruptions. However, it is now recognized that basaltic magmas may rise fast enough for disequilibrium processes to play a key role on the ascent dynamics. The quantification of the characteristic times for crystallization and exsolution processes are fundamental to our understanding of such disequilibria and ascent dynamics. Here we use observations from Mount Etna's 2001 eruption and a magma ascent model to constrain timescales for crystallization and exsolution processes. Our results show that plagioclase reaches equilibrium in 1-2 h, whereas ascent times were magma ascent rate and disequilibrium crystallization and exsolution plays a key role in controlling eruption dynamics in basaltic volcanism.

  13. Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply.

    Science.gov (United States)

    Olive, J-A; Behn, M D; Ito, G; Buck, W R; Escartín, J; Howell, S

    2015-10-16

    Recent studies have proposed that the bathymetric fabric of the seafloor formed at mid-ocean ridges records rapid (23,000 to 100,000 years) fluctuations in ridge magma supply caused by sealevel changes that modulate melt production in the underlying mantle. Using quantitative models of faulting and magma emplacement, we demonstrate that, in fact, seafloor-shaping processes act as a low-pass filter on variations in magma supply, strongly damping fluctuations shorter than about 100,000 years. We show that the systematic decrease in dominant seafloor wavelengths with increasing spreading rate is best explained by a model of fault growth and abandonment under a steady magma input. This provides a robust framework for deciphering the footprint of mantle melting in the fabric of abyssal hills, the most common topographic feature on Earth. Copyright © 2015, American Association for the Advancement of Science.

  14. Earthquake swarms reveal submarine magma unrest induced by distant mega-earthquakes: Andaman Sea region

    Czech Academy of Sciences Publication Activity Database

    Špičák, Aleš; Vaněk, Jiří

    2016-01-01

    Roč. 116, February (2016), s. 155-163 ISSN 1367-9120 Institutional support: RVO:67985530 Keywords : earthquake swarms * magma migration * submarine volcanic arc Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.335, year: 2016

  15. Disclosing Multiple Magma Degassing Sources Offers Unique Insights of What's Behind the Campi Flegrei Caldera Unrest

    Science.gov (United States)

    Moretti, R.; Civetta, L.; Orsi, G.; Arienzo, I.; D'Antonio, M.; Di Renzo, V.

    2013-12-01

    The definition of the structure and evolution of the magmatic system of Campi Flegrei caldera (CFc), Southern Italy, has been a fundamental tool for the assessment of the short-term volcanic hazard. The ensemble of geophysical and petrologic data show that the CFc magmatic system has been -and still is- characterized by two major reservoirs at different depths. From the deep one (around 8 km), less evolved magmas crystallize and degas, supplying fluids and magmas to the shallow (3-4 km) reservoirs. A thorough reconstruction of processes occurring in magma chamber/s prior and/or during the CFc eruptions has shown that magmas entering shallow reservoirs mixed with resident and crystallized batches. Also the 1982-85 unrest episode has been related to a magma intrusion of 2.1 x 10^7 m^3 at 3-4 km depth, on the basis of geophysical data (ground deformation, gravimetry, seismic imaging) and their interpretation. Thermodynamic evaluation of magma properties, at the time of emplacement, suggests for such an intrusion a bulk density of 2.000 kg/m^3 . Such a value testifies the high amount of exsolved volatiles within the system. The available record of geochemical and isotopic data on surface fumaroles, coupled with melt inclusion data, has already shown that dual (deep and shallow) magma degassing from such two reservoirs, as well as their interaction with the hydrothermal system, allows explaining the relevant fluctuations observed at crater fumaroles after the 1982-85 magma intrusion. An important role was played by the rapid crystallization (around 30 years) of the shallow magma, such that in the recent years gas discharges should be fuelled mostly by the deep magma. Such a process is well recorded in the fumarolic gas composition of the last ~10 years, but has to be reconciled with the unrest dynamics which took place after year 2000, characterized by a slow but continuous ground uplift. All geochemical indicators (major species and noble gases) point to three possible

  16. Summary of a meeting on non-electrical energy extraction from fusion reactors at AEC Germantown Headquarters, March 20, 1973

    International Nuclear Information System (INIS)

    Miley, G.H.

    1973-01-01

    The following six topics were discussed at the meeting: (1) energy forms available from the plasma, (2) materials processing, (3) hydrogen production, (4) plasma chemistry/radiation processing, (5) coherent radiation/broad-band radiation, and (6) neutron applications. Summaries are given for each topic. (U.S.)

  17. A method for extraction of crystallography-related information from a data cube of very-low-energy electron micrographs

    Czech Academy of Sciences Publication Activity Database

    Knápek, Alexandr; Pokorná, Zuzana

    2015-01-01

    Roč. 148, JAN 2015 (2015), s. 52-56 ISSN 0304-3991 R&D Projects: GA MŠk(CZ) LO1212 Keywords : Very low energy * Scanning electron microscopy * SLEEM * Data cube * Image processing Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.874, year: 2015

  18. Femtosecond pump probe spectroscopy for the study of energy transfer of light-harvesting complexes from extractions of spinach leaves

    CSIR Research Space (South Africa)

    Ombinda-Lemboumba, Saturnin

    2009-09-01

    Full Text Available been implemented at the CSIR National Laser Centre and has been applied to investigate energy transfer processes in different parts of photosynthetic systems. In this paper, researchers report on the first results obtained with Malachite green as a...

  19. Decadal to monthly timescales of magma transfer and reservoir growth at a caldera volcano.

    Science.gov (United States)

    Druitt, T H; Costa, F; Deloule, E; Dungan, M; Scaillet, B

    2012-02-01

    Caldera-forming volcanic eruptions are low-frequency, high-impact events capable of discharging tens to thousands of cubic kilometres of magma explosively on timescales of hours to days, with devastating effects on local and global scales. Because no such eruption has been monitored during its long build-up phase, the precursor phenomena are not well understood. Geophysical signals obtained during recent episodes of unrest at calderas such as Yellowstone, USA, and Campi Flegrei, Italy, are difficult to interpret, and the conditions necessary for large eruptions are poorly constrained. Here we present a study of pre-eruptive magmatic processes and their timescales using chemically zoned crystals from the 'Minoan' caldera-forming eruption of Santorini volcano, Greece, which occurred in the late 1600s BC. The results provide insights into how rapidly large silicic systems may pass from a quiescent state to one on the edge of eruption. Despite the large volume of erupted magma (40-60 cubic kilometres), and the 18,000-year gestation period between the Minoan eruption and the previous major eruption, most crystals in the Minoan magma record processes that occurred less than about 100 years before the eruption. Recharge of the magma reservoir by large volumes of silicic magma (and some mafic magma) occurred during the century before eruption, and mixing between different silicic magma batches was still taking place during the final months. Final assembly of large silicic magma reservoirs may occur on timescales that are geologically very short by comparison with the preceding repose period, with major growth phases immediately before eruption. These observations have implications for the monitoring of long-dormant, but potentially active, caldera systems.

  20. Effects of Rotation on the Differentiation of a terrestrial Magma Ocean

    Science.gov (United States)

    Maas, C.; Hansen, U.

    2014-12-01

    It is widely accepted that the Earth experienced several large impacts during its early evolution which led to the formation of one or more magma oceans. Differentiation processes in such a magma ocean are of great importance for the initial conditions of mantle convection and for the subsequent mantle structure. Convection in a magma ocean is most likely very vigorous. Further, rotation of the early Earth is supposed to be very fast. Therefore, and due to the small viscosity, it can be assumed that differentiation is strongly affected by rotation.To study the influence of rotation on the crystallization of a magma ocean, we employed a 3D Cartesian numerical model with low Prandtl number and used a discrete element method to describe silicate crystals.Our results show a crucial dependence on crystal density, rotation rate and latitude. Low rotation at the pole leads to a large fraction of suspended particles. With increasing rotation the particles settle at the bottom and form a stable stratified layer. In contrast to that at the equator at low rotation all particles settle at the bottom, at higher rotation they form a layer of significant thickness and at the highest rotation rate the particles accumulate in the middle of the magma ocean. In addition to that, we observe that due to the Coriolis force silicate crystals with different densities separate from each other. While lighter particles are at the bottom, denser particles accumulate at mid-depth at the same rotation rate. This could result in an unstable stratified mantle in the equatorial region after magma ocean solidification.All in all, rotation could lead to an asymmetrical crystallization of the magma ocean, with a contrary layering at the pole and the equator. This affects the composition of the early mantle and could explain the development of a localized magma ocean at the core-mantle boundary and the development of phase transitions observed in seismology, like the mantle transition zone.

  1. Melt zones beneath five volcanic complexes in California: an assessment of shallow magma occurrences

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, N.E.; Flexser, S.

    1984-12-01

    Recent geological and geophysical data for five magma-hydrothermal systems were studied for the purpose of developing estimates for the depth, volume and location of magma beneath each area. The areas studied were: (1) Salton Trough, (2) The Geysers-Clear Lake, (3) Long Valley caldera, (4) Coso volcanic field, and (5) Medicine Lake volcano, all located in California and all selected on the basis of recent volcanic activity and published indications of crustal melt zones. 23 figs.

  2. Bubble accumulation and its role in the evolution of magma reservoirs in the upper crust.

    Science.gov (United States)

    Parmigiani, A; Faroughi, S; Huber, C; Bachmann, O; Su, Y

    2016-04-28

    Volcanic eruptions transfer huge amounts of gas to the atmosphere. In particular, the sulfur released during large silicic explosive eruptions can induce global cooling. A fundamental goal in volcanology, therefore, is to assess the potential for eruption of the large volumes of crystal-poor, silicic magma that are stored at shallow depths in the crust, and to obtain theoretical bounds for the amount of volatiles that can be released during these eruptions. It is puzzling that highly evolved, crystal-poor silicic magmas are more likely to generate volcanic rocks than plutonic rocks. This observation suggests that such magmas are more prone to erupting than are their crystal-rich counterparts. Moreover, well studied examples of largely crystal-poor eruptions (for example, Katmai, Taupo and Minoan) often exhibit a release of sulfur that is 10 to 20 times higher than the amount of sulfur estimated to be stored in the melt. Here we argue that these two observations rest on how the magmatic volatile phase (MVP) behaves as it rises buoyantly in zoned magma reservoirs. By investigating the fluid dynamics that controls the transport of the MVP in crystal-rich and crystal-poor magmas, we show how the interplay between capillary stresses and the viscosity contrast between the MVP and the host melt results in a counterintuitive dynamics, whereby the MVP tends to migrate efficiently in crystal-rich parts of a magma reservoir and accumulate in crystal-poor regions. The accumulation of low-density bubbles of MVP in crystal-poor magmas has implications for the eruptive potential of such magmas, and is the likely source of the excess sulfur released during explosive eruptions.

  3. Aleutian tholeiitic and calc-alkaline magma series I: The mafic phenocrysts

    Science.gov (United States)

    Kay, S. Mahlburg; Kay, Robert W.

    1985-07-01

    Diagnostic mafic silicate assemblages in a continuous spectrum of Aleutian volcanic rocks provide evidence for contrasts in magmatic processes in the Aleutian arc crust. Tectonic segmentation of the arc exerts a primary control on the variable mixing, fractional crystallization and possible assimilation undergone by the magmas. End members of the continuum are termed calc-alkaline (CA) and tholeiitic (TH). CA volcanic rocks (e.g., Buldir and Moffett volcanoes) have low FeO/MgO ratios and contain compositionally diverse phenocryst populations, indicating magma mixing. Their Ni and Cr-rich magnesian olivine and clinopyroxene come from mantle-derived mafic olivine basalts that have mixed with more fractionated magmas at mid-to lower-crustal levels immediately preceding eruption. High-Al amphibole is associated with the mafic end member. In contrast, TH lavas (e.g., Okmok and Westdahl volcanoes) have high FeO/MgO ratios and contain little evidence for mixing. Evolved lavas represent advanced stages of low pressure crystallization from a basaltic magma. These lavas contain groundmass olivine (FO 40 50) and lack Ca-poor pyroxene. Aleutian volcanic rocks with intermediate FeO/MgO ratios are termed transitional tholeiitic (TTH) and calc-alkaline (TCA). TCA magmas are common (e.g., Moffett, Adagdak, Great Sitkin, and Kasatochi volcanoes) and have resulted from mixing of high-Al basalt with more evolved magmas. They contain amphibole (high and low-Al) or orthopyroxene or both and are similar to the Japanese hypersthene-series. TTH magmas (e.g., Okmok and Westdahl) contain orthopyroxene or pigeonite or both, and show some indication of upper crustal mixing. They are mineralogically similar to the Japanese pigeonite-series. High-Al basalt lacks Mg-rich mafic phases and is a derivative magma produced by high pressure fractionation of an olivine tholeiite. The low pressure mineral assemblage of high-Al basalt results from crystallization at higher crustal levels.

  4. Magma reservoir at Mt. Vesuvius: Deeper than 10 km

    International Nuclear Information System (INIS)

    Natale, M.; Luongo, G.; Nunziata, C.; Panza, G.F.

    2005-07-01

    One- and two-dimensional Vp models were obtained by TomoVes experiment, all characterized by low Vp in the uppermost 500 m and a sharp discontinuity at about 2-3 km beneath the volcano. Large amplitude late arrivals were identified as P- to S-phases converted at the top, between 8 and 10 km deep, of a low velocity layer with a dramatic drop of Vs, from approximately 3.6 km/s to less than 1.0 km/s. Here we synthesize the interpretation of Rayleigh wave dispersion measurements, made by several authors, to delineate the extent of such anomalous layer of hot, partially molten, crust material. Our non-linear inversion of broad-band dispersion measurements, gives a thickness not greater than 0.35 km, if we assume Vs equal to 1.0 km/s. The volume occupied by this very low velocity layer, sill shaped, is compatible with the size of Mt. Vesuvius cone, but it develops above a much larger hot mass which could be the parental source as the erupted products are only few percent of magma chamber. (author)

  5. Advancement of magma fragmentation by inhomogeneous bubble distribution.

    Science.gov (United States)

    Kameda, M; Ichihara, M; Maruyama, S; Kurokawa, N; Aoki, Y; Okumura, S; Uesugi, K

    2017-12-01

    Decompression times reported in previous studies suggest that thoroughly brittle fragmentation is unlikely in actual explosive volcanic eruptions. What occurs in practice is brittle-like fragmentation, which is defined as the solid-like fracture of a material whose bulk rheological properties are close to those of a fluid. Through laboratory experiments and numerical simulation, the link between the inhomogeneous structure of bubbles and the development of cracks that may lead to brittle-like fragmentation was clearly demonstrated here. A rapid decompression test was conducted to simulate the fragmentation of a specimen whose pore morphology was revealed by X-ray microtomography. The dynamic response during decompression was observed by high-speed photography. Large variation was observed in the responses of the specimens even among specimens with equal bulk rheological properties. The stress fields of the specimens under decompression computed by finite element analysis shows that the presence of satellite bubbles beneath a large bubble induced the stress concentration. On the basis of the obtained results, a new mechanism for brittle-like fragmentation is proposed. In the proposed scenario, the second nucleation of bubbles near the fragmentation surface is an essential process for the advancement of fragmentation in an upward magma flow in a volcanic conduit.

  6. Are Ferroan Anorthosites Direct Products of the Lunar Magma Ocean?

    Science.gov (United States)

    Neal, C. R.; Draper, D. S.

    2016-01-01

    According to Lunar Magma Ocean (LMO) theory, lunar samples that fall into the ferroan anorthosite (FAN) category represent the only samples we have of of the primordial crust of the Moon. Modeling indicates that plagioclase crystallizes after >70% LMO crystallization and formed a flotation crust, depending upon starting composition. The FAN group of highlands materials has been subdivided into mafic-magnesian, mafic-ferroan, anorthositic- sodic, and anorthositic-ferroan, although it is not clear how these subgroups are related. Recent radiogenic isotope work has suggested the range in FAN ages and isotopic systematics are inconsistent with formation of all FANs from the LMO. While an insulating lid could have theoretically extend the life of the LMO to explain the range of the published ages, are the FAN compositions consistent with crystallization from the LMO? As part of a funded Emerging Worlds proposal (NNX15AH76G), we examine this question through analysis of FAN samples. We compare the results with various LMO crystallization models, including those that incorporate the influence of garnet.

  7. Solar energy conversion and storage by using Rose Extract as natural dye and nitrilotriacetic acid as reductant in photogalvanic cell

    Science.gov (United States)

    Yadav, Sushil Kumar

    2018-05-01

    Photogalvanic effect was studied in Photogalvanic cell containing Rose Extract was used as Natural Dye (Photosensitizer), Nitrilotriacetic acid (NTA) as Reductant. The observed value of photopotential and photocurrent generated by this cell were 872 mV and 176 µA, respectively. The observed power at power point was 82.18 µW and the conversion efficiency was 0.79 %. The fill factor 0.4678 was experimentally determined at the power point of the cell. The photogalvanic cell can be used in dark for 42 min., showing the storage capacity of the cell against charging time was 200 min. The effect of different parameters on electrical output of the cell was observed and a mechanism has also been proposed for the generation of photocurrent in photogalvanic cell.

  8. Radix Stellariae extract prevents high-fat-diet-induced obesity in C57BL/6 mice by accelerating energy metabolism

    Directory of Open Access Journals (Sweden)

    Yin Li

    2017-05-01

    Full Text Available Stellaria dichotoma L. is widely distributed in Ningxia and surrounding areas in northwestern China. Its root, Radix Stellariae (RS, has been used in herbal formulae for treating asthenic-fever, infection, malaria, dyspepsia in children and several other symptoms. This study investigated whether the RS extract (RSE alleviates metabolic disorders. The results indicated that RSE significantly inhibited body weight gain in high-fat (HF-diet-fed C57BL/6 mice, reduced fasting glucose levels, and improved insulin tolerance. Moreover, RSE increased the body temperature of the mice and the expression of uncoupling proteins and peroxisome proliferator-activated receptors in the white adipose tissue. Thus, RSE alleviated metabolic disorders in HF-diet-fed C57BL/6 mice by potentially activating UCP and PPAR signaling.

  9. A new device for the efficient pulverisation and extraction of myocardial biopsies for high energy phosphate analysis.

    Science.gov (United States)

    Speir, E H; Sullivan, J; Patterson, R E

    1985-07-01

    We developed a new device for processing frozen myocardial biopsies. Frozen samples of 20 to 50 mg were dropped into a 25 ml stainless steel centrifuge tube held in a custom-made aluminium container precooled in liquid nitrogen. A stainless steel pestle attached to a stainless steel disk was driven by a modified heavy-duty staple gun to pulverise the tissue rapidly at low temperatures. The tissue powder was extracted with 0.3N PCA at 0 degree C in the centrifuge tube which was then transferred to a Sorvall super-speed centrifuge. Values for adenosine triphosphate (ATP) were 5.6 +/- 0.7 mumol . g-1 wet weight (mean +/- SD). Creatine phosphate (CP) yield was 12.2 +/- 3 mumol . g-1 wet weight. The % recovery of an added internal standard for ATP was 86 +/- 18% and for CP 90 +/- 16% with the new method.

  10. Thermomechanical controls on magma supply and volcanic deformation: application to Aira caldera, Japan

    Science.gov (United States)

    Hickey, James; Gottsmann, Joachim; Nakamichi, Haruhisa; Iguchi, Masato

    2016-01-01

    Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show how spatio-temporal deformation and magma reservoir evolution are fundamentally controlled by three-dimensional thermomechanical heterogeneity. Using the example of continued inflation at Aira caldera, Japan, we demonstrate that magma is accumulating faster than it can be erupted, and the current uplift is approaching the level inferred prior to the violent 1914 Plinian eruption. Magma storage conditions coincide with estimates for the caldera-forming reservoir ~29,000 years ago, and the inferred magma supply rate indicates a ~130-year timeframe to amass enough magma to feed a future 1914-sized eruption. These new inferences are important for eruption forecasting and risk mitigation, and have significant implications for the interpretations of volcanic deformation worldwide. PMID:27619897

  11. Magma mixing in granitic rocks of the central Sierra Nevada, California

    Science.gov (United States)

    Reid, John B.; Evans, Owen C.; Fates, Dailey G.

    1983-12-01

    The El Capitan alaskite exposed in the North American Wall, Yosemite National Park, was intruded by two sets of mafic dikes that interacted thermally and chemically with the host alaskite. Comparisons of petrographic and compositional data for these dikes and alaskite with published data for Sierra Nevada plutons lead us to suggest that mafic magmas were important in the generation of the Sierra Nevada batholith. Specifically, we conclude that: (1) intrusion of mafic magmas in the lower crust caused partial melting and generation of alaskite (rhyolitic) magmas; (2) interaction between the mafic and felsic magmas lead to the observed linear variation diagrams for major elements; (3) most mafic inclusions in Sierra Nevada plutons represent chilled pillows of mafic magmas, related by fractional crystallization and granitoid assimilation, that dissolve into their felsic host and contaminate it to intermediate (granodioritic) compositions; (4) vesiculation of hydrous mafic magma upon chilling may allow buoyant mafic inclusions and their disaggregation products to collect beneath a pluton's domed ceiling causing the zoning (mafic margins-to-felsic core) that these plutons exhibit.

  12. Rapid ascent of rhyolitic magma at Chaitén volcano, Chile.

    Science.gov (United States)

    Castro, Jonathan M; Dingwell, Donald B

    2009-10-08

    Rhyolite magma has fuelled some of the Earth's largest explosive volcanic eruptions. Our understanding of these events is incomplete, however, owing to the previous lack of directly observed eruptions. Chaitén volcano, in Chile's northern Patagonia, erupted rhyolite magma unexpectedly and explosively on 1 May 2008 (ref. 2). Chaitén residents felt earthquakes about 24 hours before ash fell in their town and the eruption escalated into a Plinian column. Although such brief seismic forewarning of a major explosive basaltic eruption has been documented, it is unprecedented for silicic magmas. As precursory volcanic unrest relates to magma migration from the storage region to the surface, the very short pre-eruptive warning at Chaitén probably reflects very rapid magma ascent through the sub-volcanic system. Here we present petrological and experimental data that indicate that the hydrous rhyolite magma at Chaitén ascended very rapidly, with velocities of the order of one metre per second. Such rapid ascent implies a transit time from storage depths greater than five kilometres to the near surface in about four hours. This result has implications for hazard mitigation because the rapidity of ascending rhyolite means that future eruptions may provide little warning.

  13. Temperatures and isotopic evolution of silicic magmas, Taupo Volcanic Zone and Coromandel, New Zealand

    International Nuclear Information System (INIS)

    Blattner, P.; Rui-Zhong H.; Graham, I.J.; Houston-Eleftheriadis, C.

    1996-01-01

    A new set of oxygen and strontium isotope data on rhyolitic lavas and ignimbrites of the Taupo Volcanic Zone (TVZ) and the Coromandel Peninsula provides new limits for petrogenic models. For oxygen isotopes, the rock matrix is frequently altered, so that values for magma need to be phenocryst based. Within TVZ a trend towards more negative δ 1 8O values for more recent magmas appears likely (average before about 1 Ma and for Coromandel near 8.0 per mille; after 1 Ma near 7.5 per mille). This could indicate the gradual removal of supracrustal contaminants from the zones of magma accumulation and extrusion. Similar trends within Coromandel cannot yet be resolved. A generally positive correlation is found for oxygen and strontium isotopes of magmas. Most magmas have a limited range of isotopic values, which then becomes a fingerprint (e.g., the Mamaku, Matahina, and Waiotapu Ignimbrites). A narrow range of eruption temperatures of 880 ± 60 o C is derived from quartz-plagioclase fractionations of 0.98 ± 0.25 per mille δ 1 8O values of quartz and feldspar phenocrysts are sufficiently low to suggest interaction between surface water and magma. However, large negative oxygen isotope anomalies (such as known from Yellowstone), could be no more than partially concealed by the isotopically less depleted meteoric water of New Zealand, and have not yet been found in New Zealand. (authors). 45 refs., 6 figs., 3 tabs

  14. Trace element and isotopic effects arising from magma migration beneath mid-ocean ridges

    International Nuclear Information System (INIS)

    Kenyon, P.M.

    1990-01-01

    The trace element concentrations and isotopic ratios in the magma erupted on mid-ocean ridges may differ from those in the source material due to physical effects such as porous flow dispersion, exchange of trace elements between the fluid and solid phases during magma migration, and convective mixing in magma chambers. These differences are in addition to those produced by better known processes such as fractional crystallization and partial melting. The effects of the three former processes are described. It is predicted that magma typically reaches the sub-ridge magma chambers with a spatial heterogeneity only slightly reduced from that of the source material, but with a subdued variation in time. Convective mixing then further reduces the spatial heterogeneity. Application of the results for convective mixing to a recent Fourier analysis of 87 Sr/ 86 Sr variations along the Mid-Atlantic Ridge suggests that the falloff in amplitude of variation observed with decreasing wavelength in the Mid-Atlantic Ridge data cannot be explained by convective mixing in magma chambers. Instead, it is postulated that this falloff is due to the mechanics of the production and/or the solid-state convective mixing of chemical and isotopic heterogeneities in the solid mantle. (orig.)

  15. Thermomechanical controls on magma supply and volcanic deformation: application to Aira caldera, Japan.

    Science.gov (United States)

    Hickey, James; Gottsmann, Joachim; Nakamichi, Haruhisa; Iguchi, Masato

    2016-09-13

    Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show how spatio-temporal deformation and magma reservoir evolution are fundamentally controlled by three-dimensional thermomechanical heterogeneity. Using the example of continued inflation at Aira caldera, Japan, we demonstrate that magma is accumulating faster than it can be erupted, and the current uplift is approaching the level inferred prior to the violent 1914 Plinian eruption. Magma storage conditions coincide with estimates for the caldera-forming reservoir ~29,000 years ago, and the inferred magma supply rate indicates a ~130-year timeframe to amass enough magma to feed a future 1914-sized eruption. These new inferences are important for eruption forecasting and risk mitigation, and have significant implications for the interpretations of volcanic deformation worldwide.

  16. The oxygen isotope composition of earth's oldest rocks and evidence of a terrestrial magma ocean

    DEFF Research Database (Denmark)

    Rumble, D.; Bowring, S.; Iizuka, T.

    2013-01-01

    Analysis of Hadean and Archean rocks for O-16-O-17-O-18 isotopes demonstrates that the Terrestrial Mass Fractionation Line of oxygen isotopes has had the same slope and intercept for at least the past 4.0 and probably for as long as 4.2Ga. The homogenization of oxygen isotopes required to produce....... But other sources of heat for global melting cannot be excluded such as bolide impacts during early accretion of proto-Earth, the decay of short-lived radioactive isotopes, or the energy released during segregation of core from mantle.......Analysis of Hadean and Archean rocks for O-16-O-17-O-18 isotopes demonstrates that the Terrestrial Mass Fractionation Line of oxygen isotopes has had the same slope and intercept for at least the past 4.0 and probably for as long as 4.2Ga. The homogenization of oxygen isotopes required to produce...... such long-lived consistency was most easily established by mixing in a terrestrial magma ocean. The measured identical oxygen isotope mass fractionation lines for Earth and Moon suggest that oxygen isotope reservoirs of both bodies were homogenized at the same time during a giant moon-forming impact...

  17. Energy

    International Nuclear Information System (INIS)

    Bobin, J.L.

    1996-01-01

    Object of sciences and technologies, energy plays a major part in economics and relations between nations. Jean-Louis Bobin, physicist, analyses the relations between man and energy and wonders about fears that delivers nowadays technologies bound to nuclear energy and about the fear of a possible shortage of energy resources. (N.C.). 17 refs., 14 figs., 2 tabs

  18. Chemical Potentials of Quarks Extracted from Particle Transverse Momentum Distributions in Heavy Ion Collisions at RHIC Energies

    International Nuclear Information System (INIS)

    Zhao, Hong; Liu, Fu-Hu

    2014-01-01

    In the framework of a multisource thermal model, the transverse momentum distributions of charged particles produced in nucleus-nucleus (A-A) and deuteron-nucleus (d-A) collisions at relativistic heavy ion collider (RHIC) energies are investigated by a two-component revised Boltzmann distribution. The calculated results are in agreement with the PHENIX experimental data. It is found that the source temperature increases obviously with increase of the particle mass and incident energy, but it does not show an obvious change with the collision centrality. Then, the values of chemical potentials for up, down, and strange quarks can be obtained from the antiparticle to particle yield ratios in a wide transverse momentum range. The relationship between the chemical potentials of quarks and the transverse momentum with different centralities is investigated, too

  19. Femtosecond pump probe spectroscopy for the study of energy transfer of light-harvesting complexes from extractions of spinach leaves

    Directory of Open Access Journals (Sweden)

    L. van Rensburg

    2010-01-01

    Full Text Available Measurements of ultrafast transient processes, of temporal durations in the picosecond and femtosecond regime, are made possible by femtosecond pump probe transient absorption spectroscopy. Such an ultrafast pump probe transient absorption setup has been implemented at the CSIR National Laser Centre and has been applied to investigate energy transfer processes in different parts of photosynthetic systems. In this paper we report on our first results obtained with Malachite green as a benchmark. Malachite green was chosen because the lifetime of its excited state is well known. We also present experimental results of the ultrafast energy transfer of light-harvesting complexes in samples prepared from spinach leaves. Various pump wavelengths in the range 600–680 nm were used; the probe was a white light continuum spanning 420–700 nm. The experimental setup is described in detail in this paper. Results obtained with these samples are consistent with those expected and achieved by other researchers in this field.

  20. Energy

    CERN Document Server

    Foland, Andrew Dean

    2007-01-01

    Energy is the central concept of physics. Unable to be created or destroyed but transformable from one form to another, energy ultimately determines what is and isn''t possible in our universe. This book gives readers an appreciation for the limits of energy and the quantities of energy in the world around them. This fascinating book explores the major forms of energy: kinetic, potential, electrical, chemical, thermal, and nuclear.

  1. Magma Mixing, Mingling and Its Accompanying Isotopic and Elemental Partitioning: Records from Titanites in Guojialing-type Granodiorites and Dioritic Enclaves, Jiaodong, North China

    Science.gov (United States)

    Jiang, P.; Yang, K. F.; Fan, H. R.; Liu, X.

    2016-12-01

    The grain-scale textural and in-situ compositional analyses on accessory minerals (such as titanite, rutile, apatite, monazite, etc.) have recently been a hot topic for geologists, through which a detailed information on magmatic, metamorphic or hydrothermal process can be extracted. As an attempt to unravel the petrogenesis of Early Cretaceous Guojialing-type granodiorites and their bearing dioritic enclaves, we accomplished an integrated geochronological and geochemical study on titanites within these rocks. Three types of titanites, with distinguishable textural and geochemical features, are identified. G-type titanites (from granodiorites) and E-type-I titanites (from plagioclase-rich dioritic enclaves) yield identical U-Pb age of 130 Ma, but reveal distinct back-scattered electron (BSE) zonings. G-type titanites are characterized by oscillatory zonings whereas E-type-I titanites are marked by core-mantle-rim zonings, exhibiting drastic but contrary variation trends for several key elements (such as LREEs, Zr, Hf and F) among their transition BSE zones. These two types of titanites are interpreted to crystallize coevally, and record a notable temperature and compositional change of two corresponding melts, as a response to magma mixing. E-type-II titanites (from plagioclase-poor dioritic enclaves) yield a relatively younger U-Pb age at 128 Ma, and show typical interstitial growth with narrower and lower range of Zr, total REEs contents, but higher F content and Nb/Ta ratios. Such titanites are perceived to record late-stage mingling, during which F-rich and REE-poor hybrid granodioritic magma squeezed into the incompletely consolidated dioritic enclaves with accompanying fluid-rock interaction. Unlike the dramatic elemental changes in these differentiated titanites, in-situ Nd isotopic compositions are relatively homogeneous, which in our view is a good sign of showing that isotopic equilibrium among two magma systems was more easily reached compared to

  2. Interactions between wall rocks around magma and hot water. Magma shuhen no hekigan/nessui sogo sayo

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, K.

    1992-12-01

    This paper describes interactions between wall rocks around magma and hot water. The paper discusses effects of hydrothermal environments on dynamic properties of rock minerals with respect to hydrolytic weakening (decrease in dynamic strength of a mineral under presence of water) and reaction enhanced deformation (deformation accelerated by chemical change occurring in a mineral itself). It also explains chemical reactivity of minerals under hydrothermal enviroments with respect to four types of chemical changes in minerals, factors governing mineral dissolution rates, and importance of equilibrium and non-equilibrium in main components in reactions between minerals and waters. These statements quote mainly results of indoor experiments. The paper indicates the following matters as problems to be discussed on interactions between wall rocks around intrusive rocks and hot waters: Deviation from chemical equilibrium in reactions between rocks and waters; change in permeability as a result of reactions between rocks and waters; and possibilities of hydrolytic weakening in rocks around intrusive rock bodies. 52 refs., 6 figs.

  3. The change of magma chamber depth in and around the Baekdu Volcanic area from late Cenozoic

    Science.gov (United States)

    Lee, S. H.; Oh, C. W.; Lee, Y. S.; Lee, S. G.; Liu, J.

    2016-12-01

    The Baekdu Volcano is a 2750m high stratovolcanic cone resting on a basaltic shield and plateau and locates on the North Korea-China border. Its volcanic history can be divided into four stages (from the oldest to the youngest): (i) preshield plateau-forming eruptions, (ii) basalt shield formation, (iii) construction of a trachytic composite cone, and (iv) explosive ignimbrite forming eruptions. In the First stage, a fissure eruption produced basalts from the Oligocene to the Miocene (28-13 Ma) forming preshield plateau. Fissure and central eruptions occurred together during the shield-forming eruptions (4.21-1.70 Ma). In the third stage, the trachytic composite volcano formed during the Pleistocene (0.61-0.09 Ma). In this stage, magma changed to an acidic melt. The latest stage has been characterized by explosive ignimbrite-forming eruptions during the Holocene. The composite volcanic part consists of the Xiaobaishan, Lower, Middle and Upper Trachytes with rhyolites. The whole rock and clinopyroxene in basalts, trachytic and rhyolite, are analyzed to study the depth of magma chambers under the Baekdu Volcano. From the rhyolite, 9.8-12.7kbar is obtained for the depth of magma chamber. 3.7-4.1, 8.9-10.5 and 8.7 kbar are obtained from the middle, lower and Xiaobaishan trachytes. From the first and second stage basalts, 16.9-17.0 kbar and 14-14.4kbar are obtained respectively. The first stage basalt give extrusive age of 11.98 Ma whereas 1.12 and 1.09 Ma are obtained from the feldspar and groundmass in the second stage basalt. The Xiaobaishan trachyte and rhyolite give 0.25 and 0.21 Ma whereas the Middle trachyte gives 0.07-0.06 Ma. These data indicate that the magma chambers of the first and second stage basalts were located in the mantle and the magma chamber for the second stage basalt may have been underplated below continental crust. The Xiaobisan trachyte and rhyolite originated from the magma chamber in the depth of ca. 30-40 km and the Middle trachyte

  4. Reconciling Gases With Glasses: Magma Degassing, Overturn and Mixing at Kilauea Volcano, Hawai`i

    Science.gov (United States)

    Edmonds, M.; Gerlach, T. M.

    2006-12-01

    Our understanding of the volatile budget at Kilauea Volcano is based on measurements of the abundance of volatile elements in volcanic glasses and gases. Observations of volcanic gases gave rise to a fundamental model describing volatile fractionation between the summit and rift zone during the current eruption [Gerlach and Graeber, 1985]. Other workers' analysis of glasses from the Puna Ridge, Kilauea Iki and Pu`u `O`o indicate that magma degassing, drain-back, mixing and assimilation are important processes at Kilauea Volcano. Volcanic gases have not illustrated these kinds of processes clearly in the past, owing to infrequent and poorly resolved data. New, detailed studies of volcanic gas emissions have refined our understanding of volatile degassing and magma budgets at Kilauea Volcano. Open Path Fourier Transform Infra-Red spectroscopy measurements carried out during 2004-2005 allow retrieval of the relative abundances of the major volatile species H2O, CO2 and SO2, which together make up >99 vol% of the magmatic vapor phase. The proportions of these gases vary over time and space and can be used to infer magma transport, ascent, degassing, overturn and mixing and gas segregation processes within the plumbing system of Kilauea Volcano. Gases from Pu`u `O`o in 2004-2005 display a range in composition. A trend relates molar C/S to the total H2O content of the gases over time and space; total H2O ranges from 60-98 mol %, while molar C/S ranges from 50. The range in volcanic gas composition over time and space is caused by magma degassing, overturn and mixing of partially degassed magma with fresh primary magma beneath Pu`u `O`o. Measurements of the mean rate of magma degassing (from SO2 emissions) and mean lava effusion rate (from geophysical measurements of lava tube flux) suggest that a larger volume (DRE) of magma is degassing than is being erupted, on average. This analysis suggests that magma storage in the Rift Zone might be important during eruptions as

  5. Capture, Electron-Cooling and Compression of Antiprotons in a Large Penning-Trap for Physics Experiments with an Ultra-Low Energy Extracted Antiproton Beam

    CERN Multimedia

    2002-01-01

    % PS200 \\\\ \\\\The availability of ultra-low energy antiprotons is a crucial ingredient for the execution of the gravity measurements PS200. We have developed a method to provide such low energy antiprotons based on a large Penning trap (the PS200 catching trap). This system can accept a fast-extracted pulse from LEAR, reduce the energy of the antiprotons in the pulse from 5.9~MeV to several tens of kilovolts using a degrading foil, and then capture the antiprotons in a large Penning trap. These antiprotons are cooled by electrons previously admitted to the trap and are collected in a small region at the center of the trap. We have demonstrated our capability to capture up to 1~million antiprotons from LEAR in a single shot, electron cool these antiprotons, and transfer up to 95\\% of them into the inner, harmonic region. A storage time in excess of 1 hour was observed. These results have been obtained with the cryogenic trap vacuum coupled to a room temperature vacuum at about l0$ ^- ^{1} ^0 $ Torr, which is an...

  6. U-series disequilibrium constraints on magma generation at the Jan Mayen hotspot

    Science.gov (United States)

    Rivers, E. R.; Chernow, R.; Elkins, L. J.; Sims, K. W.; Blichert-Toft, J.; Devey, C. W.

    2013-12-01

    The incompatible element-enriched magma source beneath the Jan Mayen Island hotspot influences melt generation on the adjacent northern Mid-Atlantic Ridge system and likely derives from either a small, local mantle plume, ancient Icelandic plume material emplaced in the mantle source, and/or sub-continental lithospheric mantle remnants emplaced locally by rifting of Greenland. The slow spreading Northern Kolbeinsey and Southern Mohns Ridges are immediately adjacent to Jan Mayen Island. Both have relatively shallow ridge axes, particularly the extremely shallow Eggvin Bank region of the Northern Kolbeinsey Ridge, which host anomalously large central volcanic edifices. We are currently collecting U-series disequilibrium and long-lived radiogenic isotope data for fresh, glassy mid-ocean ridge basalts from the Northern Kolbeinsey and Southern Mohns Ridge segments to better constrain source composition, depth of melting in the garnet peridotite stability field, solid mantle upwelling rates, and the nature of melt extraction beneath those segments. In particular, we are measuring isotopic data for geographically well-located samples collected from hummocky pillow basalt flows within the axial valley of the Northern Kolbeinsey Ridge segment as well as from the large volcanoes on both ridge segments, to further determine the role of the Jan Mayen hotspot in crustal construction on the Mid-Atlantic Ridge. Recently collected data show particularly high strontium isotope ratios consistent with trace element patterns that suggest a distinct local plume located beneath the Jan Mayen hotspot. A plume model for Jan Mayen is supported by new bathymetric imaging of adjacent ridge segments that reveals excess volcanism beneath the large axial volcanoes and a radial distribution of enrichment surrounding Jan Mayen Island. We predict that age-constrained U-series disequilibrium measurements will support active mantle upwelling focused beneath both Jan Mayen Island and the large axial

  7. On the Role of Mantle Overturn during Magma Ocean Solidification

    Science.gov (United States)

    Boukaré, C. E.; Parmentier, E.; Parman, S. W.

    2017-12-01

    Solidification of potential global magma ocean(s) (MO) early in the history of terrestrial planets may play a key role in the evolution of planetary interiors by setting initial conditions for their long-term evolution. Constraining this initial structure of solid mantles is thus crucial but remains poorly understood. MO fractional crystallization has been proposed to generate gravitationally unstable Fe-Mg chemical stratification capable of driving solid-state mantle overturn. Fractional solidification and overturn hypothesis, while only an ideal limiting case, can explain important geochemical features of both the Moon and Mars. Current overturn models consider generally post-MO overturn where the cumulate pile remains immobile until the end of MO solidification. However, if the cumulate pile overturns during MO solidification, the general picture of early planet evolution might differ significantly from the static crystallization models. We show that the timing of mantle overturn can be characterized with a dimensionless number measuring the ratio of the MO solidification time and the purely compositional overturn timescale. Syn-solidification overturn occurs if this dimensionless parameter, Rc, exceeds a critical value. Rc is mostly affected by the competition between the MO solidification time and mantle viscosity. Overturn that occurs during solidification can result in smaller scales of mantle chemical heterogeneity that could persist for long times thus influencing the whole evolution of a planetary body. We will discuss the effects of compaction/percolation on mantle viscosity. If partially molten cumulate do not have time to compact during MO solidification, viscosity of cumulates would be significantly lower as the interstitcial melt fraction would be large. Both solid mantle remelting during syn-solidification overturn and porous convection of melt retained with the cumulates are expected to reduce the degree of fractional crystallization. Syn

  8. Primary and secondary fragmentation of crystal-bearing intermediate magma

    Science.gov (United States)

    Jones, Thomas J.; McNamara, Keri; Eychenne, Julia; Rust, Alison C.; Cashman, Katharine V.; Scheu, Bettina; Edwards, Robyn

    2016-11-01

    Crystal-rich intermediate magmas are subjected to both primary and secondary fragmentation processes, each of which may produce texturally distinct tephra. Of particular interest for volcanic hazards is the extent to which each process contributes ash to volcanic plumes. One way to address this question is by fragmenting pyroclasts under controlled conditions. We fragmented pumice samples from Soufriere Hills Volcano (SHV), Montserrat, by three methods: rapid decompression in a shock tube-like apparatus, impact by a falling piston, and milling in a ball mill. Grain size distributions of the products reveal that all three mechanisms produce fractal breakage patterns, and that the fractal dimension increases from a minimum of 2.1 for decompression fragmentation (primary fragmentation) to a maximum of 2.7 by repeated impact (secondary fragmentation). To assess the details of the fragmentation process, we quantified the shape, texture and components of constituent ash particles. Ash shape analysis shows that the axial ratio increases during milling and that particle convexity increases with repeated impacts. We also quantify the extent to which the matrix is separated from the crystals, which shows that secondary processes efficiently remove adhering matrix from crystals, particularly during milling (abrasion). Furthermore, measurements of crystal size distributions before (using x-ray computed tomography) and after (by componentry of individual grain size classes) decompression-driven fragmentation show not only that crystals influence particular size fractions across the total grain size distribution, but also that free crystals are smaller in the fragmented material than in the original pumice clast. Taken together, our results confirm previous work showing both the control of initial texture on the primary fragmentation process and the contributions of secondary processes to ash formation. Critically, however, our extension of previous analyses to characterisation

  9. Rapid differentiation in a sill-like magma reservoir: a case study from the campi flegrei caldera.

    Science.gov (United States)

    Pappalardo, Lucia; Mastrolorenzo, Giuseppe

    2012-01-01

    In recent decades, geophysical investigations have detected wide magma reservoirs beneath quiescent calderas. However, the discovery of partially melted horizons inside the crust is not sufficient to put constraints on capability of reservoirs to supply cataclysmic eruptions, which strictly depends on the chemical-physical properties of magmas (composition, viscosity, gas content etc.), and thus on their differentiation histories. In this study, by using geochemical, isotopic and textural records of rocks erupted from the high-risk Campi Flegrei caldera, we show that the alkaline magmas have evolved toward a critical state of explosive behaviour over a time span shorter than the repose time of most volcanic systems and that these magmas have risen rapidly toward the surface. Moreover, similar results on the depth and timescale of magma storage were previously obtained for the neighbouring Somma-Vesuvius volcano. This consistency suggests that there might be a unique long-lived magma pool beneath the whole Neapolitan area.

  10. THE VISCOUS TO BRITTLE TRANSITION IN CRYSTAL- AND BUBBLE-BEARING MAGMAS

    Directory of Open Access Journals (Sweden)

    Mattia ePistone

    2015-11-01

    Full Text Available The transition from viscous to brittle behaviour in magmas plays a decisive role in determining the style of volcanic eruptions. While this transition has been determined for one- or two-phase systems, it remains poorly constrained for natural magmas containing silicic melt, crystals, and gas bubbles. Here we present new experimental results on shear-induced fracturing of three-phase magmas obtained at high-temperature (673-1023 K and high-pressure (200 MPa conditions over a wide range of strain-rates (5·10-6 s-1 to 4·10-3 s-1. During the experiments bubbles are deformed (i.e. capillary number are in excess of 1 enough to coalesce and generate a porous network that potentially leads to outgassing. A physical relationship is proposed that quantifies the critical stress required for magmas to fail as a function of both crystal (0.24 to 0.65 and bubble volume fractions (0.09 to 0.12. The presented results demonstrate efficient outgassing for low crystal fraction ( 0.44 promote gas bubble entrapment and inhibit outgassing. The failure of bubble-free, crystal-bearing systems is enhanced by the presence of bubbles that lower the critical failure stress in a regime of efficient outgassing, while the failure stress is increased if bubbles remain trapped within the crystal framework. These contrasting behaviours have direct impact on the style of volcanic eruptions. During magma ascent, efficient outgassing reduces the potential for an explosive eruption and favours brittle behaviour, contributing to maintain low overpressures in an active volcanic system resulting in effusion or rheological flow blockage of magma at depth. Conversely, magmas with high crystallinity experience limited loss of exsolved gas, permitting the achievement of larger overpressures prior to a potential sudden transition to brittle behaviour, which could result in an explosive volcanic eruption.

  11. The chemical and isotopic differentiation of an epizonal magma body: Organ Needle pluton, New Mexico

    Science.gov (United States)

    Verplanck, P.L.; Farmer, G.L.; McCurry, M.; Mertzman, S.A.

    1999-01-01

    Major and trace element, and Nd and Sr isotopic compositions of whole rocks and mineral separates from the Oligocene, alkaline Organ Needle pluton (ONP), southern New Mexico, constrain models for the differentiation of the magma body parental to this compositionally zoned and layered epizonal intrusive body. The data reveal that the pluton is rimmed by lower ??(Nd) (~-5) and higher 87Sr/86Sr (~0.7085) syenitic rocks than those in its interior (??(Nd) ~ 2, 87Sr/86Sr ~0.7060) and that the bulk compositions of the marginal rocks become more felsic with decreasing structural depth. At the deepest exposed levels of the pluton, the ??(Nd)~-5 lithology is a compositionally heterogeneous inequigranular syenite. Modal, compositional and isotopic data from separates of rare earth element (REE)-bearing major and accesory mineral phases (hornblende, titanite, apatite, zircon) demonstrate that this decoupling of trace and major elements in the inequigranular syenite results from accumulation of light REE (LREE)-bearing minerals that were evidently separated from silicic magmas as the latter rose along the sides of the magma chamber. Chemical and isotopic data for microgranular mafic enclaves, as well as for restite xenoliths of Precambrian granite wall rock, indicate that the isotopic distinction between the marginal and interior facies of the ONP probably reflects assimilation of the wall rock by ??(Nd) ~-2 mafic magmas near the base of the magma system. Fractional crystallization and crystal liquid separation of the crystally contaminated magma at the base and along the margins of the chamber generated the highly silicic magmas that ultimately pooled at the chamber top.

  12. Finite-element modeling of magma chamber-host rock interactions prior to caldera collapse

    Science.gov (United States)

    Kabele, Petr; Žák, Jiří; Somr, Michael

    2017-06-01

    Gravity-driven failure of shallow magma chamber roofs and formation of collapse calderas are commonly accompanied by ejection of large volumes of pyroclastic material to the Earth's atmosphere and thus represent severe volcanic hazards. In this respect, numerical analysis has proven as a key tool in understanding the mechanical conditions of caldera collapse. The main objective of this paper is to find a suitable approach to finite-element simulation of roof fracturing and caldera collapse during inflation and subsequent deflation of shallow magma chambers. Such a model should capture the dominant mechanical phenomena, for example, interaction of the host rock with magma and progressive deformation of the chamber roof. To this end, a comparative study, which involves various representations of magma (inviscid fluid, nearly incompressible elastic, or plastic solid) and constitutive models of the host rock (fracture and plasticity), was carried out. In particular, the quasi-brittle fracture model of host rock reproduced well the formation of tension-induced radial and circumferential fractures during magma injection into the chamber (inflation stage), especially at shallow crustal levels. Conversely, the Mohr-Coulomb shear criterion has shown to be more appropriate for greater depths. Subsequent magma withdrawal from the chamber (deflation stage) results in further damage or even collapse of the chamber roof. While most of the previous studies of caldera collapse rely on the elastic stress analysis, the proposed approach advances modeling of the process by incorporating non-linear failure phenomena and nearly incompressible behaviour of magma. This leads to a perhaps more realistic representation of the fracture processes preceding roof collapse and caldera formation.

  13. Temperatures and isotopic evolution of silicic magmas, Taupo Volcanic Zone and Coromandel, New Zealand

    International Nuclear Information System (INIS)

    Blattner, P.; Rui-Zhong, Hu; Graham, I.J.; Houston-Eleftheriadis, C.

    1996-01-01

    A new set of oxygen and strontium isotope data on rhyolitic lavas and ignimbrites of the Taupo Volcanic Zone (TVZ) and the Coromandel Peninsula provides new limits for petrogenetic models. For oxygen isotopes, the rock matrix is frequently altered, so that values for magma need to be phenocryst based. Within TVZ a trend towards more negative delta 1 8 O values for more recent magmas appears likely (average before about 1 Ma and for Coromandel near 8.0 per thousand; after 1 Ma near 7.5 per thousand). This could indicate the gradual removal of supracrustal contaminants from the zones of magma accumulation and extrusion. Similar trends within Coromandel cannot yet be resolved. A generally positive correlation is found for oxygen and strontium isotopes of magmas. Most magmas have a limited range of isotopic values, which then becomes a useful fingerprint (e.g., the Mamaku, Matahina, and Waiotapu Ignimbrites). A narrow range of eruption temperatures of 880 plus or minus 60degC is derived from quartz-plagioclase fractionations of 0.98 plus or minus 0.25 per thousand delta 1 8 O for 15 magmas. Some delta 1 8 O values of quartz and feldspar phenocrysts are sufficiently low to suggest interaction between surface water and magma. However, large negative oxygen isotope anomalies (such as known from Yellowstone), could be no more than partially concealed by the isotopically less depleted meteoric water of New Zealand, and have not yet been found in New Zealand. (author). 45 refs., 3 tabs., 6 figs

  14. Sr and Nd isotope geochemistry of coexisting alkaline magma series, Cantal, Massif Central, France

    International Nuclear Information System (INIS)

    Downes, H.

    1984-01-01

    Sr and Nd isotope analyses are presented for Tertiary continental alkaline volcanics from Cantal, Massif Central, France. The volcanics belong to two main magma series, silica-saturated and silica-undersaturated (with rare nephelinites). Trace element and isotopic data indicate a common source for the basic parental magmas of both major series; the nephelinites in contrast must have been derived from a mantle source which is isotopically and chemically distinct from that which gave rise to the basalts and basanites. 87 Sr/ 86 Sr initial ratios range from 0.7034 to 0.7056 in the main magma series (excluding rhyolites) and 143 Nd/ 144 Nd ratios vary between 0.512927 and 0.512669; both are correlated with increasing SiO 2 in the lavas. The data can be explained by a model of crustal contamination linked with fractional crystallisation. This indicates that crustal magma chambers are the sites of differentiation since only rarely do evolved magmas not show a crustal isotopic signature and conversely basic magmas have primitive isotopic ratios unless they contain obviuos crustal-derived xenocrysts. Potential contaminants include lower crustal granulites or partial melts of upper crustal units. Equal amounts of contamination are required for both magma series, refuting hypotheses of selective contamination of the silica-saturated series. The isotopic characteristics of the apparently primary nephelinite lavas demonstrates widespread heterogeneity in the mantle beneath Cantal. Some rhyolites, previously thought to be extremely contaminated or to be crustally derived, are shown to have undergone post-emplacement hydrothermal alteration. (orig.)

  15. Growing magma chambers control the distribution of small-scale flood basalts.

    Science.gov (United States)

    Yu, Xun; Chen, Li-Hui; Zeng, Gang

    2015-11-19

    Small-scale continental flood basalts are a global phenomenon characterized by regular spatio-temporal distributions. However, no genetic mechanism has been proposed to explain the visible but overlooked distribution patterns of these continental basaltic volcanism. Here we present a case study from eastern China, combining major and trace element analyses with Ar-Ar and K-Ar dating to show that the spatio-temporal distribution of small-scale flood basalts is controlled by the growth of long-lived magma chambers. Evolved basalts (SiO2 > 47.5 wt.%) from Xinchang-Shengzhou, a small-scale Cenozoic flood basalt field in Zhejiang province, eastern China, show a northward younging trend over the period 9.4-3.0 Ma. With northward migration, the magmas evolved only slightly ((Na2O + K2O)/MgO = 0.40-0.66; TiO2/MgO = 0.23-0.35) during about 6 Myr (9.4-3.3 Ma). When the flood basalts reached the northern end of the province, the magmas evolved rapidly (3.3-3.0 Ma) through a broad range of compositions ((Na2O + K2O)/MgO = 0.60-1.28; TiO2/MgO = 0.30-0.57). The distribution and two-stage compositional evolution of the migrating flood basalts record continuous magma replenishment that buffered against magmatic evolution and induced magma chamber growth. Our results demonstrate that the magma replenishment-magma chamber growth model explains the spatio-temporal distribution of small-scale flood basalts.

  16. Shallow-level magma-sediment interaction and explosive behaviour at Anak Krakatau (Invited)

    Science.gov (United States)

    Troll, V. R.; Jolis, E. M.; Dahren, B.; Deegan, F. M.; Blythe, L. S.; Harris, C.; Berg, S. E.; Hilton, D. R.; Freda, C.

    2013-12-01

    Crustal contamination of ascending arc magmas is generally thought to be a significant process which occurs at lower- to mid-crustal magma storage levels where magmas inherit their chemical and isotopic character by blending, assimilation and differentiation [1]. Anak Krakatau, like many other volcanoes, erupts shallow-level crustal xenoliths [2], indicating a potential role for upper crustal modification and hence late-stage changes to magma rheology and thus potential eruptive behaviour. Distinguishing deep vs. shallow crustal contamination processes at Krakatau, and elsewhere, is therefore crucial to understand and assess pre-eruptive magmatic conditions and their associated hazard potential. Here we report on a multi-disciplinary approach to unravel the crustal plumbing system of the persistently-active and dominantly explosive Anak Krakatau volcano [2, 3], employing rock-, mineral- and gas-isotope geochemistry and link these results with seismic tomography [4]. We show that pyroxene crystals formed at mid- and lower-crustal levels (9-11 km) and carry almost mantle-like isotope signatures (O, Sr, Nd, He), while feldspar crystals formed dominantly at shallow levels (< 5km) and display unequivocal isotopic evidence for late stage contamination (O, Sr, Nd). This obeservation places a significant element of magma-crust interaction into the uppermost, sediment-rich crust beneath the volcano. Magma storage in the uppermost crust can thus offer a possible explanation for the compositional modifications of primitive Krakatau magmas, and likely provides extra impetus to increased explosivity at Anak Krakatau. [1] Annen, et al., 2006. J. Petrol. 47, 505-539. [2] Gardner, et al., 2013. J. Petrol. 54, 149-182. [3] Dahren, et al., 2012. Contrib. Mineral. Petrol. 163, 631-651. [4] Jaxybulatov, et al., 2011. J. Volcanol. Geoth. Res. 206, 96-105.

  17. Isotopic disequilibrium among commingled hybrid magmas: Evidence for a two-stage magma mixing-commingling process in the Mt. Perkins Pluton, Arizona

    International Nuclear Information System (INIS)

    Metcalf, R.V.; Smith, E.I.; Reed, R.C.

    1995-01-01

    The syn-extensional Miocene Mt. Perkins pluton, northwestern Arizona, cooled rapidly due to its small size (6 km 2 ) and shallow emplacement (7.5 km) and allows examination of commingled rocks that experienced little isotopic exchange. Within the pluton, quartz dioritic to granodioritic host rocks (58-68 wt% SiO 2 ) enclose dioritic enclaves (50-55 wt% SiO 2 ) and a portion contains enclave-free granodiorite (70-74 wt% SiO 2 ). Fine-grained, crenulate enclave margins and a lack of advanced mixing structures (e.g., schlieren, flow fabrics, etc.) indicate an incipient stage of commingling. Isotopic variation between enclaves and enclosing host rocks is large (6.8 to 10.6 ε Nd units; 0.0036 to 0.0046 87 Sr/ 86 Sr units), suggesting isotopic disequilibrium. Comparison of an enclave core and rim suggests that isotopic exchange with the host magma was limited to the enclave rim. Enclaves and hosts collectively form a calc-alkaline suite exhibiting a large range of ε Nd (+1.2 to -12.5) and initial 87 Sr/ 86 Sr (0.705 to 0.71267) with a correlation among ε Nd , initial 87 Sr/ 86 Sr, and major and trace element compositions. Modeling suggests that the suite formed by magma hybridization involving magma mixing accompanied by fractional crystallization. The magma mixing must have predated commingling at the present exposure level and indicates a larger mixing chamber at depth. Isotopic and trace element data suggests mixing end-members were asthenospheric mantle-derived mafic and crustal-derived felsic magmas. Fractional crystallization facilitated mixing by reducing the rheological contrasts between the mafic and felsic mixing end-members. 58 refs., 11 figs., 3 tabs

  18. The electron trap parameter extraction-based investigation of the relationship between charge trapping and activation energy in IGZO TFTs under positive bias temperature stress

    Science.gov (United States)

    Rhee, Jihyun; Choi, Sungju; Kang, Hara; Kim, Jae-Young; Ko, Daehyun; Ahn, Geumho; Jung, Haesun; Choi, Sung-Jin; Myong Kim, Dong; Kim, Dae Hwan

    2018-02-01

    Experimental extraction of the electron trap parameters which are associated with charge trapping into gate insulators under the positive bias temperature stress (PBTS) is proposed and demonstrated for the first time in amorphous indium-gallium-zinc-oxide thin-film transistors. This was done by combining the PBTS/recovery time-evolution of the experimentally decomposed threshold voltage shift (ΔVT) and the technology computer-aided design (TCAD)-based charge trapping simulation. The extracted parameters were the trap density (NOT) = 2.6 × 1018 cm-3, the trap energy level (ΔET) = 0.6 eV, and the capture cross section (σ0) = 3 × 10-19 cm2. Furthermore, based on the established TCAD framework, the relationship between the electron trap parameters and the activation energy (Ea) is comprehensively investigated. It is found that Ea increases with an increase in σ0, whereas Ea is independent of NOT. In addition, as ΔET increases, Ea decreases in the electron trapping-dominant regime (low ΔET) and increases again in the Poole-Frenkel (PF) emission/hopping-dominant regime (high ΔET). Moreover, our results suggest that the cross-over ΔET point originates from the complicated temperature-dependent competition between the capture rate and the emission rate. The PBTS bias dependence of the relationship between Ea and ΔET suggests that the electric field dependence of the PF emission-based electron hopping is stronger than that of the thermionic field emission-based electron trapping.

  19. From Mush to Eruption in 1000 Years: Rapid Assembly of the Super-Sized Oruanui Magma Body

    Science.gov (United States)

    Allan, A. S.; Morgan, D. J.; Wilson, C. J.; Millet, M.

    2012-12-01

    The mush model is useful in explaining how large volumes of evolved silicic melt can be generated in and extracted from a crystal-rich source to form crystal-poor rhyolite magma bodies at shallow crustal levels. It is unclear, however, how processes of melt extraction and/or formation of the melt-dominant magma body might be reflected in the crystal record, and what physical and temporal constraints can be applied. Textural observations and in situ geochemical fingerprints in crystals from pumices of the ~25.4 ka Oruanui eruption (Taupo, New Zealand), offer new perspectives on the processes, physical conditions and timing of the melt extraction and accumulation. Almost all orthopyroxene (opx) and plagioclase (plag) cores have textures showing a period of disequilibrium (partial dissolution and/or resorption) followed by stable conditions (infilling of raddled cores; euhedral rim overgrowths). Trace element contents in amphibole (amph), which was stable and actively crystallizing in all but the most evolved parcels of Oruanui magma, complement textural evidence showing that Mn and Zn liberated by opx dissolution were preferentially sequestered in amph. Concentrations of these opx-loving elements show a prominent inflection when plotted against indices of melt evolution (e.g. Eu/Eu* in amph) marking a return to opx stability and subsequent crystallization. Plagioclase, the most abundant crystal phase, records a more complex history with significant inheritance, but textural and chemical evidence suggests that at least some of Oruanui plag crystals experienced the same departure from and return to stability as the opx. Amphibole trace element data are linked to in situ estimates of P-T-fO2 and melt H2O determined via the Ridolfi et al. (2010: Contrib Mineral Petrol 160, 45) thermobarometer. Textural and geochemical evidence combined with P-T-H2O model values indicate that three major Oruanui crystal phases (opx, amph, plag) record a significant decompression event

  20. Energy

    CERN Document Server

    Robertson, William C

    2002-01-01

    Confounded by kinetic energy? Suspect that teaching about simple machines isn t really so simple? Exasperated by electricity? If you fear the study of energy is beyond you, this entertaining book will do more than introduce you to the topic. It will help you actually understand it. At the book s heart are easy-to-grasp explanations of energy basics work, kinetic energy, potential energy, and the transformation of energy and energy as it relates to simple machines, heat energy, temperature, and heat transfer. Irreverent author Bill Robertson suggests activities that bring the basic concepts of energy to life with common household objects. Each chapter ends with a summary and an applications section that uses practical examples such as roller coasters and home heating systems to explain energy transformations and convection cells. The final chapter brings together key concepts in an easy-to-grasp explanation of how electricity is generated. Energy is the second book in the Stop Faking It! series published by NS...

  1. SU-F-J-195: On the Performance of Four Dual Energy CT Formalisms for Extracting Proton Stopping Powers

    Energy Technology Data Exchange (ETDEWEB)

    Baer, E; Royle, G [University College London, London (United Kingdom); Lalonde, A; Bouchard, H [University of Montreal, Montreal, QC (Canada)

    2016-06-15

    Purpose: Dual energy CT can predict stopping power ratios (SPR) for ion therapy treatment planning. Several approaches have been proposed recently, however accuracy and practicability in a clinical workflow are unaddressed. The aim of this work is to provide a fair comparison of available approaches in a human-like phantom to find the optimal method for tissue characterization in a clinical situation. Methods: The SPR determination accuracy is investigated using simulated DECT images. A virtual human-like phantom is created containing 14 different standard human tissues. SECT (120 kV) and DECT images (100 kV and 140 kV Sn) are simulated using the software ImaSim. The single energy CT (SECT) stoichiometric calibration method and four recently published calibration-based DECT methods are implemented and used to predict the SPRs from simulated images. The difference between SPR predictions and theoretical SPR are compared pixelwize. Mean, standard deviation and skewness of the SPR difference distributions are used as measures for bias, dispersion and symmetry. Results: The average SPR differences and standard deviations are (0.22 ± 1.27)% for SECT, and A) (−0.26 ± 1.30)%, B) (0.08 ± 1.12)%, C) (0.06 ± 1.15)% and D) (−0.05 ± 1.05)% for the four DECT methods. While SPR prediction using SECT is showing a systematic error on SPR, the DECT methods B, C and D are unbiased. The skewness of the SECT distribution is 0.57%, and A) −0.19%, B) −0.56%, C) −0.29% and D) −0.07% for DECT methods respectively. Conclusion: The here presented DECT methods B, C and D outperform the commonly used SECT stoichiometric calibration. These methods predict SPR accurately without a bias and within ± 1.2% (68th percentile). This indicates that DECT potentially improves accuracy of range predictions in proton therapy. A validation of these findings using clinical CT images of real tissues is necessary.

  2. INTERACTIONS BETWEEN GABBROID AND GRANITOID MAGMAS DURING FORMATION OF THE PREOBRAZHENSKY INTRUSION, EAST KAZAKHSTAN

    Directory of Open Access Journals (Sweden)

    S. V. Khromykh

    2017-01-01

    Full Text Available The paper reports on studies of the Preobrazhensky gabbro‐granitoid intrusion, East Kazakhstan, com‐ posed of the rocks that belong to four phases of intrusion, from quartz monzonites and gabbroids to granite‐ leucogranites. Specific relationships between basite and granitoid rocks are usually classified as the result of interac‐ tions and mixing of liquid magmas, i.e. magma mingling and mixing. Basite rocks are represented by a series from biotite gabbros to monzodiorites. Granitoids rocks are biotite‐amphibole granites. Porphyric granosyenites, com‐ bining the features of both granites and monzodiorites, are also involved in mingling. It is established that the primary granitoid magmas contained granosyenite/quartz‐monzonite and occurred in the lower‐medium‐crust conditions in equilibrium with the garnet‐rich restite enriched with plagioclase. Monzodiorites formed during fractionation of the parent gabbroid magma that originated from the enriched mantle source. We propose a magma interaction model describing penetration of the basite magma into the lower horizons of the granitoid source, which ceased below the viscoplastic horizon of granitoids. The initial interaction assumes the thermal effect of basites on the almost crystal‐ lized granitic magma and saturation of the boundary horizons of the basite magma with volatile elements, which can change the composition of the crystallizing melt from gabbroid to monzodiorite. A ‘boundary’ layer of monzodiorite melt is formed at the boundary of the gabbroid and granitoid magmas, and interacts with granitoids. Due to chemical interactions, hybrid rocks – porphyric granosyenites – are formed. The heterogeneous mixture of monzodiorites and granosyenites is more mobile in comparison with the overlying almost crystallized granites. Due to contraction frac‐ turing in the crystallized granites, the heterogeneous mixture of monzodiorites and granosyenites penetrate into the

  3. Evolution of silicic magmas in the Kos-Nisyros volcanic center: cycles associated with caldera collapse

    Science.gov (United States)

    Ruprecht, J. S.; Bachmann, O.; Deering, C. D.; Huber, C.; Skopelitis, A.; Schnyder, C.

    2010-12-01

    Multiple eruptions of silicic magma (dacite and rhyolites) occurred over the last ~ 3 My in the Kos-Nisyros volcanic center (eastern Aegean sea). Over the course of this period, magmas have changed from hornblende-biotite rich units with low eruption temperatures (≤750-800 °C; Kefalos and Kos units) to hotter (>800-850 °C), pyroxene-bearing units (Nisyros units) and are transitioning back to colder magmas (Yali units). Using bulk-rock compositions, mineral chemistry, and zircon Hf isotopes, we show that the two different types of silicic magmas followed the same differentiation trend; they all evolved by crystal fractionation (and minor assimilation) from parents with intermediate compositions characterized by high Sr/Y and low Nb content, following a wet, high oxygen fugacity liquid line of descent typical of subduction zones. As the transition between the Kos-Kefalos and Nisyros-type magmas occurred immediately and abruptly after the major caldera collapse in the area (the 161 ky Kos Plateau Tuff; KPT), we suggest that the efficient emptying of the magma chamber during the KPT drew most of the eruptible magma out and partly froze the silicic magma source zone in the upper crust due to rapid unloading, decompression and resulting crystallization. Therefore, the system had to reinstate a shallow silicic production zone from more mafic parents, recharged at temperatures typically around 850-900 °C from the mid to lower crust. The first silicic eruptions evolving from these parents after the caldera collapse (Nisyros units) were thus slightly hotter and less evolved than the Kefalos-Kos package. However, with time, the upper crustal intermediate mush grew and cooled, leading to interstitial melt compositions reaching again the highly-evolved, cold state that prevailed prior to the Kefalos-Kos. The recent (albeit not precisely dated) eruption of the high-SiO2 rhyolite of Yali suggests that another large, potentially explosive magma chamber is presently building

  4. Chronological evidence that the Moon is either young or did not have a global magma ocean.

    Science.gov (United States)

    Borg, Lars E; Connelly, James N; Boyet, Maud; Carlson, Richard W

    2011-08-17

    Chemical evolution of planetary bodies, ranging from asteroids to the large rocky planets, is thought to begin with differentiation through solidification of magma oceans many hundreds of kilometres in depth. The Earth's Moon is the archetypical example of this type of differentiation. Evidence for a lunar magma ocean is derived largely from the widespread distribution, compositional and mineralogical characteristics, and ancient ages inferred for the ferroan anorthosite (FAN) suite of lunar crustal rocks. The FANs are considered to be primary lunar flotation-cumulate crust that crystallized in the latter stages of magma ocean solidification. According to this theory, FANs represent the oldest lunar crustal rock type. Attempts to date this rock suite have yielded ambiguous results, however, because individual isochron measurements are typically incompatible with the geochemical make-up of the samples, and have not been confirmed by additional isotopic systems. By making improvements to the standard isotopic techniques, we report here the age of crystallization of FAN 60025 using the (207)Pb-(206)Pb, (147)Sm-(143)Nd and (146)Sm-(142)Nd isotopic systems to be 4,360 ± 3 million years. This extraordinarily young age requires that either the Moon solidified significantly later than most previous estimates or the long-held assumption that FANs are flotation cumulates of a primordial magma ocean is incorrect. If the latter is correct, then much of the lunar crust may have been produced by non-magma-ocean processes, such as serial magmatism.

  5. Timing of Crystallisation of the Lunar Magma Ocean Constrained by the Oldest Zircon

    Science.gov (United States)

    Nemchin, A.; Timms, N.; Pidgeon, R.; Geisler, T.; Reddy, S.; Meyer, C.

    2009-01-01

    The presently favoured concept for the early evolution of the Moon involves consolidation of debris from a giant impact of a Mars sized body with Earth forming a primitive Moon with a thick global layer of melt referred to as the Lunar Magma Ocean1 . It is widely accepted that many significant features observed on the Moon today are the result of crystallisation of this magma ocean. However, controversy exists over the precise timing and duration of the crystallisation process. Resolution of this problem depends on the establishment of precise and robust key crystallisation time points. We report a 4417 6 Myr old zircon in lunar breccia sample 72215,195, which provides a precisely determined younger limit for the solidification of the Lunar Magma Ocean. A model based on these data, together with the age of the Moon forming giant impact, defines an exponential time frame for crystallisation and suggests formation of anorthositic crust after about 80-85% of the magma ocean was solidified. In combination with other zircon ages the 4417 +/- 6 Myr age also suggests that the very small (less than a few per cent) residual portion of the magma ocean continued to solidify during the following 300-500 m.y.

  6. Transport of metals and sulphur in magmas by flotation of sulphide melt on vapour bubbles

    Science.gov (United States)

    Mungall, J. E.; Brenan, J. M.; Godel, B.; Barnes, S. J.; Gaillard, F.

    2015-03-01

    Emissions of sulphur and metals from magmas in Earth’s shallow crust can have global impacts on human society. Sulphur-bearing gases emitted into the atmosphere during volcanic eruptions affect climate, and metals and sulphur can accumulate in the crust above a magma reservoir to form giant copper and gold ore deposits, as well as massive sulphur anomalies. The volumes of sulphur and metals that accumulate in the crust over time exceed the amounts that could have been derived from an isolated magma reservoir. They are instead thought to come from injections of multiple new batches of vapour- and sulphide-saturated magmas into the existing reservoirs. However, the mechanism for the selective upward transfer of sulphur and metals is poorly understood because their main carrier phase, sulphide melt, is dense and is assumed to settle to the bottoms of magma reservoirs. Here we use laboratory experiments as well as gas-speciation and mass-balance models to show that droplets of sulphide melt can attach to vapour bubbles to form compound drops that float. We demonstrate the feasibility of this mechanism for the upward mobility of sulphide liquids to the shallow crust. Our work provides a mechanism for the atmospheric release of large amounts of sulphur, and contradicts the widely held assumption that dense sulphide liquids rich in sulphur, copper and gold will remain sequestered in the deep crust.

  7. Onset of solid state mantle convection and mixing during magma ocean solidification

    Science.gov (United States)

    Maurice, Maxime; Tosi, Nicola; Samuel, Henri; Plesa, Ana-Catalina; Hüttig, Christian; Breuer, Doris

    2017-04-01

    The fractional crystallization of a magma ocean can cause the formation of a compositional layering that can play a fundamental role for the subsequent long-term dynamics of the interior, for the evolution of geochemical reservoirs, and for surface tectonics. In order to assess to what extent primordial compositional heterogeneities generated by magma ocean solidification can be preserved, we investigate the solidification of a whole-mantle Martian magma ocean, and in particular the conditions that allow solid state convection to start mixing the mantle before solidification is completed. To this end, we performed 2-D numerical simulations in a cylindrical geometry. We treat the liquid magma ocean in a parametrized way while we self-consistently solve the conservation equations of thermochemical convection in the growing solid cumulates accounting for pressure-, temperature- and, where it applies, melt-dependent viscosity as well as parametrized yield stress to account for plastic yielding. By testing the effects of different cooling rates and convective vigor, we show that for a lifetime of the liquid magma ocean of 1 Myr or longer, the onset of solid state convection prior to complete mantle crystallization is likely and that a significant part of the compositional heterogeneities generated by fractionation can be erased by efficient mantle mixing.

  8. Magmatic architecture within a rift segment: Articulate axial magma storage at Erta Ale volcano, Ethiopia

    Science.gov (United States)

    Xu, Wenbin; Rivalta, Eleonora; Li, Xing

    2017-10-01

    Understanding the magmatic systems beneath rift volcanoes provides insights into the deeper processes associated with rift architecture and development. At the slow spreading Erta Ale segment (Afar, Ethiopia) transition from continental rifting to seafloor spreading is ongoing on land. A lava lake has been documented since the twentieth century at the summit of the Erta Ale volcano and acts as an indicator of the pressure of its magma reservoir. However, the structure of the plumbing system of the volcano feeding such persistent active lava lake and the mechanisms controlling the architecture of magma storage remain unclear. Here, we combine high-resolution satellite optical imagery and radar interferometry (InSAR) to infer the shape, location and orientation of the conduits feeding the 2017 Erta Ale eruption. We show that the lava lake was rooted in a vertical dike-shaped reservoir that had been inflating prior to the eruption. The magma was subsequently transferred into a shallower feeder dike. We also find a shallow, horizontal magma lens elongated along axis inflating beneath the volcano during the later period of the eruption. Edifice stress modeling suggests the hydraulically connected system of horizontal and vertical thin magmatic bodies able to open and close are arranged spatially according to stresses induced by loading and unloading due to topographic changes. Our combined approach may provide new constraints on the organization of magma plumbing systems beneath volcanoes in continental and marine settings.

  9. Decoding how a soil bacterium extracts building blocks and metabolic energy from ligninolysis provides road map for lignin valorization

    Science.gov (United States)

    Varman, Arul M.; He, Lian; Follenfant, Rhiannon; Wu, Weihua; Wemmer, Sarah; Wrobel, Steven A.; Tang, Yinjie J.; Singh, Seema

    2016-01-01

    Sphingobium sp. SYK-6 is a soil bacterium boasting a well-studied ligninolytic pathway and the potential for development into a microbial chassis for lignin valorization. An improved understanding of its metabolism will help researchers in the engineering of SYK-6 for the production of value-added chemicals through lignin valorization. We used 13C-fingerprinting, 13C metabolic flux analysis (13C-MFA), and RNA-sequencing differential expression analysis to uncover the following metabolic traits: (i) SYK-6 prefers alkaline conditions, making it an efficient host for the consolidated bioprocessing of lignin, and it also lacks the ability to metabolize sugars or organic acids; (ii) the CO2 release (i.e., carbon loss) from the ligninolysis-based metabolism of SYK-6 is significantly greater than the CO2 release from the sugar-based metabolism of Escherichia coli; (iii) the vanillin catabolic pathway (which is the converging point of majority of the lignin catabolic pathways) is coupled with the tetrahydrofolate-dependent C1 pathway that is essential for the biosynthesis of serine, histidine, and methionine; (iv) catabolic end products of lignin (pyruvate and oxaloacetate) must enter the tricarboxylic acid (TCA) cycle first and then use phosphoenolpyruvate carboxykinase to initiate gluconeogenesis; and (v) 13C-MFA together with RNA-sequencing differential expression analysis establishes the vanillin catabolic pathway as the major contributor of NAD(P)H synthesis. Therefore, the vanillin catabolic pathway is essential for SYK-6 to obtain sufficient reducing equivalents for its healthy growth; cosubstrate experiments support this finding. This unique energy feature of SYK-6 is particularly interesting because most heterotrophs rely on the transhydrogenase, the TCA cycle, and the oxidative pentose phosphate pathway to obtain NADPH. PMID:27634497

  10. Towards a comprehensive classification of igneous rocks and magmas

    Science.gov (United States)

    Middlemost, Eric A. K.

    1991-08-01

    QAPF modal classification. The QAPF and TAS classifications are regarded as being of equal validity, with the TAS classification being of more practical value in the classification of the common volcanic rocks and the various magmas conjured up in petrogenetic discussions. A new, comprehensive, hierarchical classification of igneous rocks is introduced, and the petrographic character and systematic position of the various rocks and clans that make up this classification are reviewed.

  11. Assisted extraction of the energy level spacings and lever arms in direct current bias measurements of one-dimensional quantum wires, using an image recognition routine

    International Nuclear Information System (INIS)

    Lesage, A. A. J.; Smith, L. W.; Griffiths, J. P.; Farrer, I.; Jones, G. A. C.; Ritchie, D. A.; Smith, C. G.; Al-Taie, H.; Kelly, M. J.; See, P.

    2015-01-01

    A multiplexer technique is used to individually measure an array of 256 split gates on a single GaAs/AlGaAs heterostructure. This results in the generation of large volumes of data, which requires the development of automated data analysis routines. An algorithm is developed to find the spacing between discrete energy levels, which form due to transverse confinement from the split gate. The lever arm, which relates split gate voltage to energy, is also found from the measured data. This reduces the time spent on the analysis. Comparison with estimates obtained visually shows that the algorithm returns reliable results for subband spacing of split gates measured at 1.4 K. The routine is also used to assess direct current bias spectroscopy measurements at lower temperatures (50 mK). This technique is versatile and can be extended to other types of measurements. For example, it is used to extract the magnetic field at which Zeeman-split 1D subbands cross one another

  12. Development of a pepper-pot emittance meter for diagnostics of low-energy multiply charged heavy ion beams extracted from an ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Nagatomo, T., E-mail: nagatomo@riken.jp; Kase, M.; Kamigaito, O.; Nakagawa, T. [Nishina Center for Accelerator Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Tzoganis, V. [Nishina Center for Accelerator Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Cockcroft Institute, Daresbury, Warrington WA4 4AD (United Kingdom); Department of Physics, University of Liverpool, Liverpool, Merseyside L69 3BX (United Kingdom)

    2016-02-15

    Several fluorescent materials were tested for use in the imaging screen of a pepper-pot emittance meter that is suitable for investigating the beam dynamics of multiply charged heavy ions extracted from an ECR ion source. SiO{sub 2} (quartz), KBr, Eu-doped CaF{sub 2}, and Tl-doped CsI crystals were first irradiated with 6.52-keV protons to determine the effects of radiation damage on their fluorescence emission properties. For such a low-energy proton beam, only the quartz was found to be a suitable fluorescent material, since the other materials suffered a decay in fluorescence intensity with irradiation time. Subsequently, quartz was irradiated with heavy {sup 12}C{sup 4+}, {sup 16}O{sup 4+}, and {sup 40}Ar{sup 11+} ions, but it was found that the fluorescence intensity decreased too rapidly to measure the emittance of these heavy-ion beams. These results suggest that a different energy loss mechanism occurs for heavier ions and for protons.

  13. Energy

    International Nuclear Information System (INIS)

    1975-10-01

    On the occasion of the World Environment Day the Norwegian Ministry for the Environment held a conference on growth problems in energy consumption. The themes which were treated were energy conservation, hydroelectric power, the role of nuclear power, radioactive waste disposal, fossil fuel resources, ecological limits, pollution and international aspects. Nuclear energy forms the main theme of one lecture and an aspect of several others. (JIW)

  14. Energy

    OpenAIRE

    Torriti, Jacopo

    2016-01-01

    The impact of energy policy measures has been assessed with various appraisal and evaluation tools since the 1960s. Decision analysis, environmental impact assessment and strategic environmental assessment are all notable examples of progenitors of Regulatory Impact Assessment (RIA) in the assessment of energy policies, programmes and projects. This chapter provides overview of policy tools which have been historically applied to assess the impacts of energy policies, programmes and projects....

  15. Energies

    International Nuclear Information System (INIS)

    2003-01-01

    In the framework of the National Debate on the energies in a context of a sustainable development some associations for the environment organized a debate on the nuclear interest facing the renewable energies. The first part presents the nuclear energy as a possible solution to fight against the greenhouse effect and the associated problem of the wastes management. The second part gives information on the solar energy and the possibilities of heat and electric power production. A presentation of the FEE (French wind power association) on the situation and the development of the wind power in France, is also provided. (A.L.B.)

  16. The Dovyren Intrusive Complex (Southern Siberia, Russia): Insights into dynamics of an open magma chamber with implications for parental magma origin, composition, and Cu-Ni-PGE fertility

    Science.gov (United States)

    Ariskin, Alexey; Danyushevsky, Leonid; Nikolaev, Georgy; Kislov, Evgeny; Fiorentini, Marco; McNeill, Andrew; Kostitsyn, Yuri; Goemann, Karsten; Feig, Sandrin T.; Malyshev, Alexey

    2018-03-01

    The Dovyren Intrusive Complex (DIC, Northern Baikal region, 728 Ma) includes the layered dunite-troctolite-gabbronorite Yoko-Dovyren massif (YDM), associated mafic-ultramafic sills, and dykes of olivine-rich to olivine-free gabbronorite. Major rock types of the DIC are presented, including a diversity of olivine orthocumulates to olivine-plagioclase and gabbroic adcumulates, carbonate-contaminated ultramafics and Cu-Ni-PGE mineralisation. Detailed comparisons of complete cross-sections of the YDM in its centre and at the NE and SW margins demonstrate differences in the cumulate succession, mineral chemistry, and geochemical structure that likely reflect variations in parental magma compositions. Combining petrochemical reconstructions for most primitive rocks and calculations using the COMAGMAT-5 model, it is shown that the central and peripheral parts of the intrusion formed by olivine-laden parental magmas ranged in their temperatures by 100 °C, approximately from 1290 °C ( 11 wt% MgO, olivine Fo88) to 1190 °C ( 8 wt% MgO, olivine Fo86). Thermodynamic modelling suggests that the most primitive high-Mg magma was S-undersaturated, whereas its derivatives became S-saturated at T piles to generate poorly-mineralised plagiodunite. In the troctolite and gabbroic parts of the Dovyren chamber, sulphide immiscibility likely occurred at lower temperatures, producing Cu-rich sulphide precursors, which gave rise to the 'platinum group mineral' (PGM-containing) troctolite and low-mineralised PGE-rich anorth