Tryon M.D.,University of California at San Diego |
Henry P.,CEREGE |
Cagatay M.N.,Technical University of Istanbul |
Zitter T.A.C.,CEREGE |
And 6 more authors.
Geochemistry, Geophysics, Geosystems | Year: 2010
As part of the 2007 Marnaut cruise in the Sea of Marmara, an investigation of the pore fluid chemistry of sites along the Main Marmara Fault zone was conducted. The goal was to define the spatial relationship between active faults and fluid outlets and to determine the sources and evolution of the fluids. Sites included basin bounding transtensional faults and strike-slip faults cutting through the topographic highs. The basin pore fluids are dominated by simple mixing of bottom water with a brackish, low-density Pleistocene Lake Marmara end-member that is advecting buoyantly and/or diffusing from a relatively shallow depth. This mix is overprinted by shallow redox reactions and carbonate precipitation. The ridge sites are more complex with evidence for deep-sourced fluids including thermogenic gas and evidence for both silicate and carbonate diagenetic processes. One site on the Western High displayed two mound structures that appear to be chemoherms atop a deep-seated fluid conduit. The fluids being expelled are brines of up to twice seawater salinity with an exotic fluid chemistry extremely high in Li, Sr, and Ba. Oil globules were observed both at the surface and in cores, and type II gas hydrates of thermogenic origin were recovered. Hydrate formation near the seafloor contributes to increase brine concentration but cannot explain their chemical composition, which appears to be influenced by diagenetic reactions at temperatures of 75°C-150°C. Hence, a potential source for fluids at this site is the water associated with the reservoir from which the gas and oil is seeping, which has been shown to be related to the Thrace Basin hydrocarbon system. Our work shows that submerged continental transform plate boundaries can be hydrologically active and exhibit a diversity of sources and processes. Copyright 2010 by the American Geophysical Union.
ECMOR 2012 - 13th European Conference on the Mathematics of Oil Recovery | Year: 2012
Continuous media theory in physics uses the Von Karman's theory to describe the shape, strains and stresses of thin plates, non Euclidian thin shells or surfaces. Given a set of boundary conditions, it relates geometrical shape parameters such as the Gaussian and the mean curvatures, the physical properties of the materials such as the Young's modulus and Poisson's ratio to the bending (or flexural slip) and stretching (or pure shearing) energy terms. Layered geological structures, especially reservoir bearing structures, have typically larger lateral extents compared to their thickness, and can be considered in a first approximation as thin plates regarding their mechanical behavior. Moreover, during sedimentation the top of the sedimentary pile can be generally considered as smooth developable surfaces in the depositional space, which are then deformed during their burial history under tectonic events. This idea is used to suggest a method for identifying the probability of finding sub-seismic faults in thin geological structures or reservoirs. This paper presents theoretical results that relate the curvatures of the top or bottom surfaces of geological structures and reservoirs. Bending and stretching energy terms are used as structural attributes to predict fracturing or the deformation style.
Srama R.,University of Stuttgart |
Srama R.,Max Planck Institute for Nuclear Physics |
Kruger H.,Max Planck Institute for Solar System Research |
Yamaguchi T.,Japan Aerospace Exploration Agency |
And 65 more authors.
Experimental Astronomy | Year: 2012
The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission. © 2012 Springer Science+Business Media B.V.
Wilson C.F.,University of Oxford |
Chassefiere E.,University Paris - Sud |
Hinglais E.,French National Center for Space Studies |
Baines K.H.,NASA |
And 21 more authors.
Experimental Astronomy | Year: 2012
The European Venus Explorer (EVE) mission described in this paper was proposed in December 2010 to ESA as an 'M-class' mission under the Cosmic Vision programme. It consists of a single balloon platform floating in the middle of the main convective cloud layer of Venus at an altitude of 55 km, where temperatures and pressures are benign (~25°C and ~0. 5 bar). The balloon float lifetime would be at least 10 Earth days, long enough to guarantee at least one full circumnavigation of the planet. This offers an ideal platform for the two main science goals of the mission: study of the current climate through detailed characterization of cloud-level atmosphere, and investigation of the formation and evolution of Venus, through careful measurement of noble gas isotopic abundances. These investigations would provide key data for comparative planetology of terrestrial planets in our solar system and beyond. © 2011 Springer Science+Business Media B.V.
Hemelsdael R.,CRPG |
Ford M.,CRPG |
Ford M.,University of Lorraine
Basin Research | Year: 2016
Established models indicate that, before being breached, relay zones along rift borders can evolve either by lengthening and rotating during progressive overlap of growing fault segments (isolated fault model), or, by simply rotating without lengthening before breaching (coherent fault model). The spatio-temporal distribution of vertical motions in a relay zone can thus be used to distinguish fault growth mechanisms. Depositional relay zones that develop at sea level and accommodate both deposition on the ramp itself as well as transfer of sediments from the uplifting footwall into the hangingwall depocentres and provide the most complete record of vertical motions. We examine the development of a depositional relay ramp on the border of the active Corinth rift, Greece to reconstruct fault interaction in time and space using both onshore and offshore (2D seismic lines) data. The Akrata relay zone developed over a period of ca. 0.5 Myr since the Middle Pleistocene between the newly forming East Helike Fault (EHF) that propagated towards the older, more established Derveni Fault (DF). The relay zone captured the Krathis River, which deposited prograding Gilbert-type deltas on the sub-horizontal ramp. Successive oblique faults record progressive linkage and basinward migration of accommodation along the ramp axis, whereas marine terraces record diachronous uplift in their footwalls. Although early linkage of the relay zone occurs, continuous propagation and linkage of the EHF onto the static DF is recorded before final beaching. Rotation on forced folds above the upward and laterally propagating normal faults at the borders of the relay zone represents the ramp hinges. The Akrata relay zone cannot be compared directly to a simple fault growth model because (1) the relay zone connects two fault segments of different generations; (2) multiple linkages during propagation was facilitated by the presence of pre-existing crustal structures, inherited from the Hellenide fold and thrust belt. The linkage of the EHF to the DF contributed to the westward and northward propagation of the southern rift border. © 2016 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.
Ehrenfreund P.,Leiden Institute of Chemistry |
Ehrenfreund P.,Space Policy Institute |
Ulamec S.,German Aerospace Center |
Barucci M.A.,LESIA Observatoire de Paris |
And 9 more authors.
Proceedings of the International Astronautical Congress, IAC | Year: 2012
MarcoPolo-R is a sample return mission to a primitive Near-Earth Asteroid (NEA) selected in February 2011 for the Assessment Study Phase in the framework of ESA's Cosmic Vision 2 program. MarcoPolo-R is a European mission and takes advantage of three completed industrial studies. MarcoPolo-R will rendezvous with a unique kind of target, the primitive binary NEA (175706) 1996 FG3. The MarcoPolo mission will scientifically characterize the binary NEA system at multiple scales, and return a unique pristine sample to Earth unaltered by the atmospheric entry process or terrestrial weathering. The binary target provides enhanced science return: precise measurements of the mutual orbit and rotation state of both components can be used to probe higher-level harmonics of the gravitational potential, and therefore the internal structure. The main goal of the MarcoPolo-R mission is to return unaltered NEA material for detailed analysis in ground-based laboratories which will allow scientists to study the most primitive materials available to investigate early Solar System formation processes. Copyright © (2012) by the International Astronautical Federation.
Blaise T.,CNRS Georesources lab |
Blaise T.,Andra Inc |
Tarantola A.,CNRS Georesources lab |
Cathelineau M.,CNRS Georesources lab |
And 6 more authors.
Chemical Geology | Year: 2015
Past water circulations can significantly reduce the porosity and permeability of marine limestones. This is particularly the case in the Middle (Bathonian/Bajocian) to Upper (Oxfordian) Jurassic limestones from the eastern border of the Paris Basin. The knowledge of the timing, the temperature and composition of paleowaters is essential to model the hydrological evolution in this area where the Callovian-Oxfordian claystones are studied for the storage of nuclear wastes. In this way, fluid inclusions hosted in low-temperature (<60°C) authigenic calcite, quartz and celestite crystals were analyzed by Raman spectroscopy and mass spectrometry to determine the chlorinity and D/H ratios. Chlorinity measurements (mmol Cl per liter of water) in fluid inclusions trapped in authigenic crystals during the late Jurassic/early Cretaceous period revealed unexpected high values, up to 3800 mmol l-1, indicating that brines were involved in some of the diagenetic crystallization processes. By contrast, fluid inclusions in calcite cements of Cenozoic age within the Oxfordian limestones have low Cl concentration (less than 150 mmol l-1), thus showing that a dilution event caused by water infiltrations during the Cretaceous uplift of this part of the basin has flushed out the original saline porewater. By coupling δD of fluid inclusion with δ18O of calcite crystals, we estimate that calcite precipitation occurred at temperatures between 25 and 53°C. The hydrogen isotope composition of calcite-forming water is different between the Middle Jurassic (δD ranging from -20 to -35.8‰V-SMOW) and the overlying Oxfordian limestone (δD from -59.5 to -44.8‰V-SMOW). Present-day groundwaters are also of distinct composition on both sides of the Oxfordian claystones, indicating that limestone aquifers underwent independent hydrologic evolutions since the early diagenetic Jurassic cementation. © 2015 Elsevier B.V.
News Article | March 4, 2016
Amelia Trainer can recite the Seamus Heaney poem, “Scaffolding,” by memory. It starts: Masons, when they start upon a building, Are careful to test out the scaffolding; Make sure that planks won't slip at busy points, Secure all ladders, tighten bolted joints. Trainer, a sophomore majoring in physics and nuclear science and engineering, calls “Scaffolding” “probably the most true and meaningful love poem I’ve read.” But its metaphorical take on a relationship might also resonate for Trainer around her work with the Computational Reactor Physics Group (CRPG), where Trainer is deeply committed to learning about strengthening structures in a nuclear realm. Since early in her freshman year, Trainer has been part of a team helping refine OpenMC Monte Carlo, a powerful computational code for modeling neutron behavior inside nuclear reactors. Developed by the CRPG, with support from the U.S. Department of Energy, OpenMC offers the possibility of “simulations that recreate the world inside a reactor,” Trainer says. “This means we can make operating reactors safer, improve future designs, and avoid doing costly experiments. It’s the coolest thing ever.” Her engagement with this research has already earned recognition: She won an outstanding Undergraduate Research Opportunity Project (UROP) award, and presented a paper to the American Nuclear Society Student Conference in 2015, all based on work she performed in freshman year. In OpenMC simulations, scientists are interested in testing a variety of reactor parameters, including operating temperature. But it can be time-consuming to generate simulation data for a large number of nuclides at specific temperatures, and research suggested it might be possible to achieve comparably accurate results by instead interpolating between specific temperatures. Trainer’s research tested this hypothesis by comparing different interpolation models with actual experiments. “Instead of generating data for nuclear material at 293 kelvins, we could say the data roughly equals some material at 250 K and some at 300 K while preserving accuracy,” Trainer says. “We can save time with a shortcut like this, and make everyone’s life easier.” Trainer got a running start on this project. “I began pestering Jon Walsh [a PhD candidate working in the CRPG group under the direction of professors Kord Smith and Benoit Forget] with emails looking for a research project before freshman orientation,” she says. “I can’t emphasize how much I like this project and the research group as a whole.” Given her avid interest in this work, and her double major, it is somewhat surprising to learn that as late as the summer before senior year in high school Trainer was uncertain about attending college. In her Florida high school, some students didn’t bother, and Trainer, while a top scholar and math team member, was happy serving up ice cream at a beach shop. “I enjoyed food service,” she says. “I had a million things in my head to think about and I got paid for a job that left my mind free to wander all day.” But Trainer soon shifted course. She’d had a revelation in physics class: “The most excited I’d been in high school was when a teacher described how nuclear reactors worked, what E=mc2 is, and I thought I should learn more about this stuff.” She also won a scholarship to Embry-Riddle Aeronautical University to learn computer coding, and discovered she had a knack for programming. Then, after a friend in a fantasy basketball league suggested she was accomplished enough to attend college, Trainer decided to apply to MIT. Today, not even halfway through her undergraduate career, Trainer believes she has found her calling: “I’m very happy with what I’m working on now,” she says. “Why change a good thing?” Her software writing proficiency has proved essential: She interned at Los Alamos National Laboratory last summer as a code developer, one of only a few undergraduates in her division. Coding is also central to her current CRPG research, which involves processing giant data libraries generated by the national laboratories into compact versions whose parameters are used by CRPG codes for the purposes of performing reactor simulations. She is also comparing U.S. data libraries to those of other countries, which are based on different assumptions and experiments. At this point, Trainer says she would like nothing better than to pursue an academic career “just trying slowly to add to the bank of what people understand about nuclear energy, furthering computational tools.” She would be especially pleased to do this at MIT. “I have an opportunity to be at the forefront, studying under the most brilliant minds, and if I don’t take advantage of this, I’d be completely missing out,” Trainer says.
News Article | October 23, 2015
Professor Kord Smith of the Department of Nuclear Science and Engineering has been selected as the 2015 recipient of the American Nuclear Society (ANS) Eugene P. Wigner Reactor Physicist Award. He is cited for a career of outstanding contributions to the field of reactor physics. The Eugene P. Wigner Reactor Physicist Award honors individuals who have made outstanding contributions to the advancement of the field of reactor physics. This award was established in honor of the late Eugene P. Wigner, a designer of nuclear reactors during the Manhattan Project of World War II, who was awarded the 1963 Nobel Prize in Physics "for his contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry principles". Smith is the 20th recipient of the award. The late Allan Henry who was a professor of nuclear engineering at MIT and Smith’s PhD advisor received the award in 1992. Smith is the Korea Electric Power Company (KEPCO) Professor of the Practice of Nuclear Science and Engineering at MIT and chief scientist in the U.S. Department of Energy's Office of Science, Center for Exascale Simulation of Advanced Reactors (CESAR). His research focuses on the development and application of advanced computational physics methods for modeling and simulation of nuclear reactor cores: computational reactor physics methods, fuel/core loading design and optimization, transient safety analysis, real-time operator training, and online plant monitoring. Smith, Professor Benoit Forget, and their students who form the Computational Reactor Physics Group (CRPG) at MIT focus their research efforts on advanced computational methods and numerical algorithms in nuclear reactor analysis. CRPG research has resulted in the development and deployment of the Open-Source computational codes OpenMC and OpenMOC that are used by research organizations around the world. Ongoing work focuses on development and application of deterministic mathematical operators (physics-based multi-grid methods) to accelerate solutions of stochastic Monte Carlo neutral particle transport, to enable efficient multi-physics coupling to thermal conduction and fluid flow, and to extend Monte Carlo transport applications into the time domain. Smith and MIT CRPG students are actively engaged in exploring the frontiers of advanced scientific computing at CESAR. The center provides unique opportunities for MIT students to be involved in large interdisciplinary high-performance computing (HPC) projects that explore interactions between simulation software and emerging hardware architectures. CRPG students research such topics as the development of new algorithmic approaches for large-scale graphical processor unit utilization, elimination of cache bottlenecks on massive-core node architectures, and design of physics algorithms to exploit hardware vector operations while minimizing memory and cache latencies. CESAR plays a key role in responding to President Obama’s July 2015 executive order that established the National Strategic Computing Initiative.This initiative seeks to ensure that the United States continues leading in the development and application of HPC systems that are essential to economic competitiveness, scientific discovery, and national security. The Wigner award will be presented to Smith at the ANS Winter Meeting in Washington in November. Smith will deliver the signature Wigner Lecture highlighting his numerous technical contributions to the field of nuclear reactor physics during the ANS Summer Meeting in June 2016 in New Orleans. See the full list of recipients.
News Article | October 23, 2015
The frenetic dance of neutrons inside a nuclear reactor generates heat and produces electricity. Reactor physicist Lulu Li wants to make sense of this kinetic choreography, with the ultimate goal, she says, of “making nuclear reactors safer, more reliable, and economical to operate.” A fourth-year doctoral student and member of the Computational Reactor Physics Group (CRPG) in MIT's Department of Nuclear Science and Engineering (NSE), Li is developing precise and detailed simulations of neutron behavior that could have a major impact on current and future generations of nuclear reactors. Under the direction of NSE professors and faculty advisors Kord Smith and Benoit Forget, Li has created a new method for accelerating the solution of neutron-transport equations — mathematical characterizations of the movements made by neutrons in time and space from the moment the first atom of nuclear fuel undergoes fission. “We want to know how many neutrons there are, where they’re going, and with what energy and velocity,” says Li. Li and her colleagues’ mathematical simulations are intended to reduce uncertainties in nuclear plants, which must operate within strict safety limits. More accurate models of neutron behavior will give plant designers a better way of characterizing the safety limits of current and new designs, thus improving fuel efficiency and operations. “The better we understand things inside, the more economic value we can get out of a reactor,” says Li. While equations have long existed for modeling neutrons, recent advances in computing power now make possible much faster fine-grained mathematical simulations. “Supercomputers enable us to develop methods that were not previously possible to execute, and to accomplish them in a reasonable timeframe,” says Li. With two other graduate students, Li created a new modeling platform, called the open-source method of characteristics neutron-transport code (OpenMOC), which was published in the Annals of Nuclear Energy last June. She presented research related to this platform at the U.S. Department of Energy’s Consortium for Advanced Simulation of Light Wave Reactors, where she won the best poster award at its 2014 workshop. Li’s interest in devising algorithms for accelerating reactor simulations emerged after a summer internship in 2009 following her sophomore year at Rhodes College in Tennessee. A physics major, she applied for an internship with MIT’s Department of Nuclear Science and Engineering. “Back then, I confused nuclear engineering and nuclear physics, so I came here with the wrong assumption.” It turned out to be a happy mistake for Li. “People in the department here were extremely friendly, and taught me stuff from scratch,” she recounts. “I knew how to perform tasks on the computer, but nothing about theory, and over the summer they helped me catch up.” Li also met the research group she works with now, which led to a second internship the following summer. “They were amazing mentors, passionate and really patient with me. That’s what ultimately helped me decide what to do.” Li completed her undergraduate education in physics at the University of Illinois at Urbana-Champaign, where she found a calling in computational programming. “I tried the experimental stuff, but realized I was no good at it,” she says. “I was never a hands-on person.” During a childhood attempt to add physical memory to a computer, Li recalls smoke billowing from the machine. “I went into mathematical simulations because you don’t have anything to break, and with the computer, you can undo any previous versions of your work,” says Li. “It totally fits who I am.” For her dissertation, Li is harnessing supercomputers to model neutron behavior in full-scale nuclear reactors. Her algorithms are intended to predict with high fidelity the behavior of individual neutrons caroming off the tiny pellets of fissile fuel material that comprise nuclear-fuel assemblies. With novel reactor concepts under development and the rising costs of experimental facilities, Li’s algorithms aid the analysis and optimization of designs at a very fundamental level. After she receives her PhD, Li is aiming for a job with industry, where she hopes to put her computations to use with the current fleet of light-water reactors, and next-generation plants as well. “I’d like to inform people who develop new reactors,” she says. “Simulation is the first-stage test bed that opens up a design space.”