The Experts below are selected from a list of 1311 Experts worldwide ranked by ideXlab platform
Od Mullen - One of the best experts on this subject based on the ideXlab platform.
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Functions and Requirements for a Waste Conveyance Jet Pump for the Gunite and Associated Tanks at Oak Ridge National Laboratory
1998Co-Authors: Od MullenAbstract:Since the mid 1940's, the U.S. Department of Defense (DOD) and the U.S. Department of Energy (DOE) have conducted research and development activities at the Oak Ridge National Laboratory (ORNL) in support of urgent national interests in the fields of nuclear weaponry and nuclear energy. Some of these activities resulted in radiologically hazardous waste being temporarily deposited at ORNL in Waste Area Grouping 1. At this location, waste is stored in several underground storage tanks, awaiting ultimate final disposal. There are tanks of two basic categories; one category is referred to as the "Gunite" tanks, and the other category is `associated" tanks. The ORNL Gunite and Associated Tanks Treatability Study (GMT-TS) project was initiated in fiscal year (FY) 1994 to support a record of decision in selecting from seven different options of technologies for retrieval and remediation of these tanks. This decision process is part of a Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), Remedial investigation and Feasibility Study (R1/FS) presented to DOE and the Tennessee Department of Environment and Conservation (TDEC). As part of this decision process, new waste retrieval technologies were evaluated at the 25-ft diameter Gunite tanks in the North Tank Farm.
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functions and requirements for a waste dislodging and conveyance system for the Gunite and associated tanks treatability study at oak ridge national laboratory
Other Information: PBD: Feb 1997, 1997Co-Authors: J D Potter, Od MullenAbstract:Since the mid 1940s, the Department of Defense (DOD) and the Department of Energy (DOE) have conducted research and development activities at the Oak Ridge National Laboratory (ORNL) in support of urgent national interests in the fields of nuclear weaponry and nuclear energy. Some of these activities resulted in radiologically hazardous waste being temporarily deposited at ORNL, Waste Area Grouping 1. At this location, waste is stored in several underground storage tanks, awaiting ultimate final disposal. There are tanks of two basic categories. One category is referred to as the Gunite tanks, the other category is associated tanks. The ORNL Gunite and Associated Tanks Treatability Study (GAAT TS) project was initiated in FY 1994 to support a record of decision in selecting from seven different options of technologies for retrieval and remediation of these tanks. As part of this decision process, new waste retrieval technologies will be evaluated at the 25-foot diameter Gunite tanks in the North tank farm. Work is currently being conducted at Hanford and the University of Missouri-Rolla to evaluate and develop some technologies having high probability of being most practical and effective for the dislodging and conveying of waste from underground storage tanks. The findings of these efforts indicate that a system comprised of a dislodging end effector employing jets of high-pressure fluids, coupled to a water-jet conveyance system, all carried above the waste by a mechanical arm or other mechanism, is a viable retrieval technology for the GAAT TS tasks.
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functions and requirements for a waste dislodging and conveyance system for the Gunite and associated tanks treatability study at oak ridge national laboratory
Other Information: PBD: Sep 1995, 1995Co-Authors: J D Potter, Od MullenAbstract:Functions and requirements for the Waste Dislodging and Conveyance System to be deployed in Gunite and Associated Tanks (GAAT) and tested and evaluated as a candidate tank waste retrieval technology by the GAAT Treatability Study (GAAT TS).
Nick Hudyma - One of the best experts on this subject based on the ideXlab platform.
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alkali silica reaction possible cause of map cracking in Gunite
Journal of Performance of Constructed Facilities, 2003Co-Authors: Moses Karakouzian, Mehmet N. Okuyan, Nick HudymaAbstract:In this case study, a number of Gunite swimming pools exhibited extensive map or alligator cracking that caused rough and uneven surfaces. The nature of the cracking pointed to alkali-silica reaction (ASR) as the cause of the cracking. Four test methods, the uranyl acetate method, petrographic examination, chemical analysis by electron microprobe, and X-ray diffraction, were used to investigate the presence of ASR within the Gunite. Results showed (1) some evidence of ASR gel within the Gunite using uranyl acetate; (2) the potential existence of alkali silica gel throughout the cement and within the fractures of the sand grains based on petrographic examination; (3) elevated levels of total alkali, indicating a potential for ASR to occur based on chemical analysis; and (4) tiny inclusions of thermonatrite (commonly found in ASR gel) based on X-ray diffraction. Results from each of the four test methods suggest, albeit inconclusively, the existence of ASR in the Gunite. Additionally, the results of all of the four test methods did not contradict each other. Accordingly, it can be stated with some certainty that the distress in the Gunite was due to ASR.
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Alkali-Silica Reaction—Possible Cause of Map Cracking in Gunite
Journal of Performance of Constructed Facilities, 2003Co-Authors: Moses Karakouzian, Mehmet N. Okuyan, Nick HudymaAbstract:In this case study, a number of Gunite swimming pools exhibited extensive map or alligator cracking that caused rough and uneven surfaces. The nature of the cracking pointed to alkali-silica reaction (ASR) as the cause of the cracking. Four test methods, the uranyl acetate method, petrographic examination, chemical analysis by electron microprobe, and X-ray diffraction, were used to investigate the presence of ASR within the Gunite. Results showed (1) some evidence of ASR gel within the Gunite using uranyl acetate; (2) the potential existence of alkali silica gel throughout the cement and within the fractures of the sand grains based on petrographic examination; (3) elevated levels of total alkali, indicating a potential for ASR to occur based on chemical analysis; and (4) tiny inclusions of thermonatrite (commonly found in ASR gel) based on X-ray diffraction. Results from each of the four test methods suggest, albeit inconclusively, the existence of ASR in the Gunite. Additionally, the results of all of the four test methods did not contradict each other. Accordingly, it can be stated with some certainty that the distress in the Gunite was due to ASR.
J D Potter - One of the best experts on this subject based on the ideXlab platform.
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functions and requirements for a waste dislodging and conveyance system for the Gunite and associated tanks treatability study at oak ridge national laboratory
Other Information: PBD: Feb 1997, 1997Co-Authors: J D Potter, Od MullenAbstract:Since the mid 1940s, the Department of Defense (DOD) and the Department of Energy (DOE) have conducted research and development activities at the Oak Ridge National Laboratory (ORNL) in support of urgent national interests in the fields of nuclear weaponry and nuclear energy. Some of these activities resulted in radiologically hazardous waste being temporarily deposited at ORNL, Waste Area Grouping 1. At this location, waste is stored in several underground storage tanks, awaiting ultimate final disposal. There are tanks of two basic categories. One category is referred to as the Gunite tanks, the other category is associated tanks. The ORNL Gunite and Associated Tanks Treatability Study (GAAT TS) project was initiated in FY 1994 to support a record of decision in selecting from seven different options of technologies for retrieval and remediation of these tanks. As part of this decision process, new waste retrieval technologies will be evaluated at the 25-foot diameter Gunite tanks in the North tank farm. Work is currently being conducted at Hanford and the University of Missouri-Rolla to evaluate and develop some technologies having high probability of being most practical and effective for the dislodging and conveying of waste from underground storage tanks. The findings of these efforts indicate that a system comprised of a dislodging end effector employing jets of high-pressure fluids, coupled to a water-jet conveyance system, all carried above the waste by a mechanical arm or other mechanism, is a viable retrieval technology for the GAAT TS tasks.
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functions and requirements for a waste dislodging and conveyance system for the Gunite and associated tanks treatability study at oak ridge national laboratory
Other Information: PBD: Sep 1995, 1995Co-Authors: J D Potter, Od MullenAbstract:Functions and requirements for the Waste Dislodging and Conveyance System to be deployed in Gunite and Associated Tanks (GAAT) and tested and evaluated as a candidate tank waste retrieval technology by the GAAT Treatability Study (GAAT TS).
Yan Liang - One of the best experts on this subject based on the ideXlab platform.
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high porosity channels for melt migration in the mantle top is the dunite and bottom is the harzburgite and lherzolite
Geophysical Research Letters, 2010Co-Authors: Yan Liang, Alan Schiemenz, Marc A Hesse, Marc E Parmentier, Jan S HesthavenAbstract:High-porosity dunite channels are important pathways for melt migration in the mantle. To better understand the first order characteristics of the high-porosity melt channel and its associated peridotite lithologies in an upwelling mantle, we conducted high-resolution numerical simulations of reactive dissolution in a deformable porous medium. Results from this study show that high-porosity dunite channels are transient and shallow parts of pathways for melt migration in the mantle. The lower parts of a high-porosity channel are harzburgite and lherzolite. The size and dimension of dunite channels depend on the amplitude of lateral porosity variations at the base of the melting column, whereas the depth of dunite channel initiation depends on the melt flux entering the channel from below. Compaction and interaction between compaction and dissolution play a central role in distributing melt in the dunite channel. A wide orthopyroxene-free dunite channel may contain two or more high-porosity melt channels. A primary high-porosity melt channel developed in the deep mantle may excite secondary melt channels in the shallow part of the melting column. The spatial relations among the high-porosity melt channel and its associated lithologies documented in this study may shed new light on a number of field, petrological, and geochemical observations related to melt migration in the mantle. Citation: Liang, Y., A. Schiemenz, M. A. Hesse, E. M. Parmentier, and J. S. Hesthaven (2010), High-porosity channels for melt migration in the mantle: Top is the dunite and bottom is the harzburgite and lherzolite, Geophys. Res. Lett., 37, L15306, doi:10.1029/2010GL044162.
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An experimental study of the kinetics of lherzolite reactive dissolution with applications to melt channel formation
Contributions to Mineralogy and Petrology, 2005Co-Authors: Zachary Morgan, Yan LiangAbstract:The kinetics of lherzolite dissolution in an alkali basalt and a basaltic andesite was examined experimentally at 1,300°C and 1 GPa using the dissolution couple method. Dissolution of lherzolite in basaltic liquids produces either the melt-bearing dunite–harzburgite–lherzolite (DHL) sequence or the melt-bearing harzburgite–lherzolite sequence depending on whether the reacting melt is or close to olivine saturation (alkali basalt) or olivine + orthopyroxene saturation (basaltic andesite). The dunite in the DHL sequence is pyroxene-free and the harzburgites in both sequences are clinopyroxene-free. The melt fraction and olivine grain size in the dunite are larger than those in the harzburgite. The olivine grain size in the dunite and harzburgite in the DHL sequence also increases as a function experimental run time. Across the sharp dunite–harzburgite and harzburgite–lherzolite interfaces, systematic compositional variations are observed in the reacting melt, interstitial melt, olivine, and to a lesser extent, pyroxenes as functions of distance and time. The systematic variations in lithology, grain size, mineral chemistry, and melt compositions are broadly similar to those observed in the mantle sections of ophiolites. The processes of lherzolite dissolution in basaltic liquids involve dissolution, precipitation, reprecipitation, and diffusive transport in the interstitial melts and surrounding minerals. Preferential dissolution of olivine and clinopyroxene and precipitation of orthopyroxene in the basaltic andesite produces the melt-bearing harzburgite–lherzolite sequence. Preferential dissolution of clinopyroxene and orthopyroxene and precipitation of olivine results in the melt-bearing DHL sequence. Preferential mineral dissolution can also affect the composition of the through-going melt in a dunite channel or harzburgite matrix. Systematic variations in melt fraction and mineral grain size in the peridotite sequences are likely to play an important role in the development of channelized or diffuse porous melt flow in the mantle.
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an experimental and numerical study of the kinetics of harzburgite reactive dissolution with applications to dunite dike formation
Earth and Planetary Science Letters, 2003Co-Authors: Zachary Morgan, Yan LiangAbstract:Abstract The mechanisms and kinetics of harzburgite reactive dissolution in basaltic liquids were examined using a combined experimental and numerical approach. Dissolution experiments were conducted at 1250–1290°C and 0.6–0.75 GPa using dissolution couples consisting of pre-synthesized rods of alkali basalt and harzburgite in graphite and platinum-lined molybdenum capsules. Reactive dissolution of harzburgite produces a melt-bearing, orthopyroxene-free dunite with a sharp mineralogical front at the dunite–harzburgite interface. The thickness of the dunite layer is proportional to the square root of experimental run time, and its growth rate is limited by the rates of diffusion of major components in the melt. Around the sharp mineralogical front there exists a broad composition boundary layer where major and trace element abundances in the interstitial melt and olivine vary systematically as a function of distance and time. The sharp mineralogical front and the broad composition boundary layer result from a combined effect of orthopyroxene and olivine dissolution at the dunite–harzburgite interface, olivine re-precipitation within the dunite, as well as diffusive exchange between the crystals and the melts. Based on experimental observations a simple model for harzburgite reactive dissolution was developed and used to extrapolate the experimentally measured dissolution rates and concentration profiles to conditions relevant to melt transport under the mid-ocean ridge. Model calculations demonstrate that diffusive dissolution alone is incapable of producing dunite dikes wider than a few meters within the time scale of mantle upwelling under the mid-ocean ridge. Prevalent melt percolation, hence large melt–rock ratios, is required in the formation of large dunite channels in the mantle. The composition of the reacting melt is of particular importance in determining the composition gradients in olivine across the dunite–harzburgite interface. By adjusting the reacting melt compositions we were able to produce concentration profiles broadly similar to those observed in our experiments as well as those reported across the dunite–harzburgite sharp contacts in the mantle sections of ophiolites and peridotite massifs around the world.
Moses Karakouzian - One of the best experts on this subject based on the ideXlab platform.
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alkali silica reaction possible cause of map cracking in Gunite
Journal of Performance of Constructed Facilities, 2003Co-Authors: Moses Karakouzian, Mehmet N. Okuyan, Nick HudymaAbstract:In this case study, a number of Gunite swimming pools exhibited extensive map or alligator cracking that caused rough and uneven surfaces. The nature of the cracking pointed to alkali-silica reaction (ASR) as the cause of the cracking. Four test methods, the uranyl acetate method, petrographic examination, chemical analysis by electron microprobe, and X-ray diffraction, were used to investigate the presence of ASR within the Gunite. Results showed (1) some evidence of ASR gel within the Gunite using uranyl acetate; (2) the potential existence of alkali silica gel throughout the cement and within the fractures of the sand grains based on petrographic examination; (3) elevated levels of total alkali, indicating a potential for ASR to occur based on chemical analysis; and (4) tiny inclusions of thermonatrite (commonly found in ASR gel) based on X-ray diffraction. Results from each of the four test methods suggest, albeit inconclusively, the existence of ASR in the Gunite. Additionally, the results of all of the four test methods did not contradict each other. Accordingly, it can be stated with some certainty that the distress in the Gunite was due to ASR.
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Alkali-Silica Reaction—Possible Cause of Map Cracking in Gunite
Journal of Performance of Constructed Facilities, 2003Co-Authors: Moses Karakouzian, Mehmet N. Okuyan, Nick HudymaAbstract:In this case study, a number of Gunite swimming pools exhibited extensive map or alligator cracking that caused rough and uneven surfaces. The nature of the cracking pointed to alkali-silica reaction (ASR) as the cause of the cracking. Four test methods, the uranyl acetate method, petrographic examination, chemical analysis by electron microprobe, and X-ray diffraction, were used to investigate the presence of ASR within the Gunite. Results showed (1) some evidence of ASR gel within the Gunite using uranyl acetate; (2) the potential existence of alkali silica gel throughout the cement and within the fractures of the sand grains based on petrographic examination; (3) elevated levels of total alkali, indicating a potential for ASR to occur based on chemical analysis; and (4) tiny inclusions of thermonatrite (commonly found in ASR gel) based on X-ray diffraction. Results from each of the four test methods suggest, albeit inconclusively, the existence of ASR in the Gunite. Additionally, the results of all of the four test methods did not contradict each other. Accordingly, it can be stated with some certainty that the distress in the Gunite was due to ASR.