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2011

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Articles 7471 - 7500 of 7728

Full-Text Articles in Physical Sciences and Mathematics

Generic Trace Logics, Christian Kissig, Alexander Kurz Jan 2011

Generic Trace Logics, Christian Kissig, Alexander Kurz

Engineering Faculty Articles and Research

We combine previous work on coalgebraic logic with the coalgebraic traces semantics of Hasuo, Jacobs, and Sokolova.

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A Green Board As A Climate-Change Imperative: Appointing A Climate-Change Expert To The Audit Committee, Porcher L. Taylor Iii, Harris L. Kay Jan 2011

A Green Board As A Climate-Change Imperative: Appointing A Climate-Change Expert To The Audit Committee, Porcher L. Taylor Iii, Harris L. Kay

School of Professional and Continuing Studies Faculty Publications

This article makes the innovative and timely case for a climate change imperative: a green board. Urgency is evident, with the arrival of "a fast-emerging new burden on board members to oversee their company's posture on climate change and to begin monitoring an area that, until now, has drawn scant attention in the boardroom."21 One major impetus for the proposal advocated in this Article is that there is apparently a dearth of green boards in corporate America.22 In contrast, European and Canadian companies appear to be at the vanguard of utilizing green boards.23

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Real-Time Behavior-Based Robot Control, Brian G. Woolley, Gilbert L. Peterson, Jared T. Kresge Jan 2011

Real-Time Behavior-Based Robot Control, Brian G. Woolley, Gilbert L. Peterson, Jared T. Kresge

Faculty Publications

Behavior-based systems form the basis of autonomous control for many robots, but there is a need to ensure these systems respond in a timely manner. Unexpected latency can adversely affect the quality of an autonomous system’s operations, which in turn can affect lives and property in the real-world. A robots ability to detect and handle external events is paramount to providing safe and dependable operation. This paper presents a concurrent version of a behavior-based system called the Real-Time Unified Behavior Framework, which establishes a responsive basis of behavior-based control that does not bind the system developer to any single behavior …

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The Behavior Of Nanothermite Reaction Based On Bi2o3/Al, L. Wang, D. Luss, Karen S. Martirosyan Jan 2011

The Behavior Of Nanothermite Reaction Based On Bi2o3/Al, L. Wang, D. Luss, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

We studied the impact of aluminum particle size and the thickness of surrounding alumina layer on the dynamic pressure discharge of nanothermite reactions in the Bi2O3/Al system. A pressure discharge from 9 to 13 MPa was generated using as-synthesized Bi2O3 nano-particles produced by combustion synthesis and Al nanoparticles with size from 3 μm to 100 nm. The maximum reaction temperature was measured to be ∼2700 °C. The estimated activation energy of the reaction was 45 kJ/mol. A very large (several orders of magnitude) difference existed between the rate of the pressure pulse release by nanothermite reactions and by thermite …

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Directional Limits On Persistent Gravitational Waves Using Ligo S5 Science Data, J. Abadie, B. P. Abbott, Matthew Benacquista, Teviet Creighton, R. Grosso, J. Li, Soma Mukherjee, Soumya Mohanty, Malik Rakhmanov, Volker Quetschke, Robert Stone, Joseph D. Romano, B. Vaishnav Jan 2011

Directional Limits On Persistent Gravitational Waves Using Ligo S5 Science Data, J. Abadie, B. P. Abbott, Matthew Benacquista, Teviet Creighton, R. Grosso, J. Li, Soma Mukherjee, Soumya Mohanty, Malik Rakhmanov, Volker Quetschke, Robert Stone, Joseph D. Romano, B. Vaishnav

Physics & Astronomy Faculty Publications

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2−20×10−50  strain2 Hz−1 and 5−35×10−49  strain2 Hz−1 sr−1 for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW …

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Magnetization Precession And Domainwall Structure In Cobalt-Ruthenium-Cobalt Trilayers, Zhen Li, Ralph Skomski, Sy-Hwang Liou, Steven Michalski, Mircea Chipara, Roger D. Kirby Jan 2011

Magnetization Precession And Domainwall Structure In Cobalt-Ruthenium-Cobalt Trilayers, Zhen Li, Ralph Skomski, Sy-Hwang Liou, Steven Michalski, Mircea Chipara, Roger D. Kirby

Physics & Astronomy Faculty Publications

The magnetization dynamics of Co(5 nm)/Ru/Co(5 nm) trilayers with Ru thicknesses from 0.3–0.6 nm is experimentally and theoretically investigated. The coupling between the Co layers is antiferromagnetic (AFM) and yields a stable AFM domain structure with frozen domain walls. Comparing high-resolution magnetic force microscopy (MFM) and pump-probe measurements, we analyze the behavior of the films for different field-strength regimes. For moderate magnetic fields, pump-probe measurements provide dynamic characterization of the coupled precessional modes in the GHz range. The dynamics at small fields is realized by the pinning of AFM domain walls at inhomogeneities. The MFM images yield a domain-wall width …

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Teaching Introductory Undergraduate Physics Using Commercial Video Games, Soumya Mohanty, Sergio Cantu Jan 2011

Teaching Introductory Undergraduate Physics Using Commercial Video Games, Soumya Mohanty, Sergio Cantu

Physics & Astronomy Faculty Publications

Commercial video games are increasingly using sophisticated physics simulations to create a more immersive experience for players. This also makes them a powerful tool for engaging students in learning physics. We provide some examples to show how commercial off-the-shelf games can be used to teach specific topics in introductory undergraduate physics. The examples are selected from a course taught predominantly through the medium of commercial video games.

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Biometrics Technology: Understanding Dynamics Influencing Adoption For Control Of Identification Deception Within Nigeria, Gideon U. Nwatu Jan 2011

Biometrics Technology: Understanding Dynamics Influencing Adoption For Control Of Identification Deception Within Nigeria, Gideon U. Nwatu

Walden Dissertations and Doctoral Studies

One of the objectives of any government is the establishment of an effective solution to significantly control crime. Identity fraud in Nigeria has generated global attention and negative publicity toward its citizens. The research problem addressed in this study was the lack of understanding of the dynamics that influenced the adoption and usability of biometrics technology for reliable identification and authentication to control identity deception. The support for this study was found in the theoretical framework of the technology acceptance model (TAM). The purpose of the study was to provide scholarly research about the factors that influenced the adoption of …

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Editorial, Jo De Waele Jan 2011

Editorial, Jo De Waele

International Journal of Speleology

No abstract provided.

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A Note On The Occurrence Of A Crayback Stalagmite At Niah Caves, Borneo, Joyce Lundberg, Donald A. Mcfarlane Jan 2011

A Note On The Occurrence Of A Crayback Stalagmite At Niah Caves, Borneo, Joyce Lundberg, Donald A. Mcfarlane

International Journal of Speleology

Crayback stalagmites have mainly been reported from New South Wales, Australia. Here we document a small crayback in the entrance of Painted Cave (Kain Hitam), part of the Niah Caves complex in Sarawak, Borneo. Measuring some 65 cm in length and 18 cm in height, this deposit is elongate in the direction of the dominant wind and thus oriented towards the natural tunnel entrance. It shows the classic humpbacked long profile, made up of small transverse segments or plates, in this case the tail extending towards the entrance. The dark blue-green colour down the centre suggests that cyanobacterial growth follows …

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In Situ Acetylene Reduction Activity Of Scytonema Julianum In Vapor Cave (Spain), Antonia Dolores Asencio, Marina Aboal Jan 2011

In Situ Acetylene Reduction Activity Of Scytonema Julianum In Vapor Cave (Spain), Antonia Dolores Asencio, Marina Aboal

International Journal of Speleology

Nitrogen fixation was measured in situ for the first time by acetylene reduction for a greyish mat composed of Scytonema julianum in cave-like environments. Mat-specific rates (129.9-215.7 nmol C2 H4 m-2 s-1 for daytime fixation and 65.1-120.6 nmol C2 H4 m-2 s-1 for nighttime fixation) recorded in the Vapor cave differed considerably due to the energy reserves stored during photosynthesis being exhausted and used in the dark phase. The most influential environmental parameter for nitrogen fixation in the Vapor cave is temperature in the daytime and nighttime fixations. Nitrogen fixation by cyanobacteria may contribute considerably to the overall nitrogen cycle …

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Minerogenetic Mechanisms Occurring In The Cave Environment: An Overview, Bogdan P. Onac, Paolo Forti Jan 2011

Minerogenetic Mechanisms Occurring In The Cave Environment: An Overview, Bogdan P. Onac, Paolo Forti

International Journal of Speleology

Perhaps man’s first motivation to explore caves, beyond using them as shelter, was the search for substances that were not available elsewhere: most of them were minerals. However, for a long time it was believed that the cave environment was not very interesting from the mineralogical point of view. This was due to the fact that most cave deposits are normally composed of a single compound: calcium carbonate. Therefore, the systematic study of cave mineralogy is of only recent origin. However, although only a limited number of natural cavities have been investigated in detail, about 350 cave minerals have already …

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The Present Day Genesis And Evolution Of Cave Minerals Inside The Ojo De La Reina Cave (Naica Mine, Mexico), Giovanni Badino, José Maria Calaforra, Paolo Forti, Paolo Garofalo, Laura Sanna Jan 2011

The Present Day Genesis And Evolution Of Cave Minerals Inside The Ojo De La Reina Cave (Naica Mine, Mexico), Giovanni Badino, José Maria Calaforra, Paolo Forti, Paolo Garofalo, Laura Sanna

International Journal of Speleology

Ojo de la Reina is the first and the smallest cave intersected at the -290 level in the Naica Mine (Mexico), therefore it was the first cavity in which the lowering of temperature induced by mine ventilation caused condensation over crystals’ surface since 2005. The consequent dissolution of the gypsum crystals and subsequent condensed water evaporation lead to the deposition of several new minerals, among which some highly soluble Mg/Na compounds (bloedite, epsomite, halite, hexahydrite, kieserite, starkeyite). The single available source of Mg and Na ions in this minerogenetic environment is represented by the huge fluid inclusions widespread within the …

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The First Cave Occurrence Of Orpiment (As₂S₃) From The Sulfuric Acid Caves Of Aghia Paraskevi (Kassandra Peninsula, N. Greece), Georgios Lazaridis, Vasilios Melfos, Lambrini Papadopoulou Jan 2011

The First Cave Occurrence Of Orpiment (As₂S₃) From The Sulfuric Acid Caves Of Aghia Paraskevi (Kassandra Peninsula, N. Greece), Georgios Lazaridis, Vasilios Melfos, Lambrini Papadopoulou

International Journal of Speleology

Orpiment, tamarugite and pickeringite occur in close association above the surface of thermal water cave pools in the active sulfuric acid caves of Aghia Paraskevi on the Kassandra peninsula, northern Greece. Gypsum also occurs as small interstitial crystals or encrustations. Orpiment is of high significance since it has not previously been reported as a cave mineral. In addition, tamarugite and pickeringite rarely occur in karst caves. Water from a borehole and a spring is of Na-Cl type and contains traces of CO2 and H2S. The B/Cl ratios indicate seawater participation with a possible mixing with geothermal water …

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Iron Oxide And Calcite Associated With Leptothrix Sp. Biofilms Within An Estavelle In The Upper Floridan Aquifer, Lee J. Florea, Chasity L. Stinson, Josh Brewer, Rick Fowler, B Joe Kearns, Anthony M. Greco Jan 2011

Iron Oxide And Calcite Associated With Leptothrix Sp. Biofilms Within An Estavelle In The Upper Floridan Aquifer, Lee J. Florea, Chasity L. Stinson, Josh Brewer, Rick Fowler, B Joe Kearns, Anthony M. Greco

International Journal of Speleology

In Thornton’s Cave, an estavelle in west-central Florida, SEM, EDS, and XRD data reveal biofilms that are predominantly comprised of FeOOH-encrusted hollow sheaths that are overgrown and intercalated with calcite. Fragments of this crystalline biofilm adhere to the walls and ceiling as water levels vary within the cave. Those on the wall have a ‘cornflake’ appearance and those affixed to the ceiling hang as fibrous membranes. PCR of DNA in the active biofilm, combined with morphologic data from the tubes in SEM micrographs, point to Leptothrix sp., a common Fe-oxidizing bacteria, as the primary organism in the biofilm. Recent discoveries …

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Table Of Contents Jan 2011

Table Of Contents

International Journal of Speleology

No abstract provided.

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Minerals And Speleothems Of The József-Hegy Cave (Budapest, Hungary), Szabolcs Leél-Őssy, Gyöngyvér Szanyi, Gergely Surányi Jan 2011

Minerals And Speleothems Of The József-Hegy Cave (Budapest, Hungary), Szabolcs Leél-Őssy, Gyöngyvér Szanyi, Gergely Surányi

International Journal of Speleology

With the discovery of the József-hegy Cave, a cave of hydrothermal origin with an abundance of minerals unknown so far in Hungary came to light. Diversity and the frequency of the occurrence of crystals make this cave similar to the Lechuguilla Cave, even if the dimensions of the mineral precipitations and the passages do not compare in scale. The variety and mass of carbonates and sulphates are surprising. This paper describes the minerals and speleothems of the József-hegy Cave, their occurrence and genesis, including determined ages. The 41 U/Th measurements suggest that speleothems begun to develop in the upper level …

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Editorial, Carol A. Hill Jan 2011

Editorial, Carol A. Hill

International Journal of Speleology

No abstract provided.

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Comparison Of 14c And U-Th Ages Of Two Holocene Phreatic Overgrowths On Speleothems From Mallorca (Western Mediterranean): Environmental Implications, Paola Tuccimei, Mark Van Strydonck, Angel Ginés, Joaquín Ginés, Michele Soligo, Igor M. Villa, Joan J. Fornós Jan 2011

Comparison Of 14c And U-Th Ages Of Two Holocene Phreatic Overgrowths On Speleothems From Mallorca (Western Mediterranean): Environmental Implications, Paola Tuccimei, Mark Van Strydonck, Angel Ginés, Joaquín Ginés, Michele Soligo, Igor M. Villa, Joan J. Fornós

International Journal of Speleology

This investigation reports on the comparison between ICP-MS U-Th and AMS 14C ages of Phreatic Overgrowths on Speleothems (POS) from two different caves on the island of Mallorca (Spain). These speleothem encrustations form at the water table of coastal caves in a low-amplitude tide-controlled microenvironment and are used to reconstruct past sea level changes. The aim of this study is to evaluate if this particular type of speleothem is datable using 14C method and to investigate possible problems connected with the incorporation of dead carbon inherited from the dissolution of 14C-free limestone. The results show that 14C ages are strongly …

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A Comparative Integrated Geophysical Study Of Horseshoe Chimney Cave, Colorado Bend State Park, Texas, Wesley A. Brown, Kevin W. Stafford, Mindy Shaw-Faulkner, Andy Grubbs Jan 2011

A Comparative Integrated Geophysical Study Of Horseshoe Chimney Cave, Colorado Bend State Park, Texas, Wesley A. Brown, Kevin W. Stafford, Mindy Shaw-Faulkner, Andy Grubbs

International Journal of Speleology

An integrated geophysical study was performed over a known cave in Colorado Bend State Park (CBSP), Texas, where shallow karst features are common within the Ellenberger Limestone. Geophysical survey such as microgravity, ground penetrating radar (GPR), direct current (DC) resistivity, capacitively coupled (CC) resistivity, induced polarization (IP) and ground conductivity (GC) measurements were performed in an effort to distinguish which geophysical method worked most effectively and efficiently in detecting the presence of subsurface voids, caves and collapsed features. Horseshoe Chimney Cave (HCC), which is part of a larger network of cave systems, provides a good control environment for this research. …

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The Subterranean Fauna Of A Biodiversity Hotspot Region - Portugal: An Overview And Its Conservation, Ana Sofia P.S. Reboleira, Paulo A.V. Borges, Fernando Gonçalves, Artur R.M. Serrano, Pedro Oromí Jan 2011

The Subterranean Fauna Of A Biodiversity Hotspot Region - Portugal: An Overview And Its Conservation, Ana Sofia P.S. Reboleira, Paulo A.V. Borges, Fernando Gonçalves, Artur R.M. Serrano, Pedro Oromí

International Journal of Speleology

An overview of the obligate hypogean fauna in Portugal (including Azores and Madeira archipelagos) is provided, with a list of obligated cave-dwelling species and subspecies, and a general perspective about its conservation. All the available literature on subterranean Biology of Portugal since the first written record in 1870 until today has been revised. A total of 43 troglobiont and 67 stygobiont species and subspecies from 12 orders have been described so far in these areas, included in the so-called Mediterranean hotspot of biodiversity. The subterranean fauna in Portugal has been considered moderately poor with some endemic relicts and it remains …

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A New Foodweb Based On Microbes In Calcitic Caves: The Cansiliella (Beetles) Case In Northern Italy, Maurizio G. Paoletti, Mattia Beggio, Angelo Leandro Dreon, Alberto Pamio, Tiziano Gomiero, Mauro Brilli, Luca Dorigo, Giuseppe Concheri, Andrea Squartini, Annette Summers Engel Jan 2011

A New Foodweb Based On Microbes In Calcitic Caves: The Cansiliella (Beetles) Case In Northern Italy, Maurizio G. Paoletti, Mattia Beggio, Angelo Leandro Dreon, Alberto Pamio, Tiziano Gomiero, Mauro Brilli, Luca Dorigo, Giuseppe Concheri, Andrea Squartini, Annette Summers Engel

International Journal of Speleology

The troglobitic beetle, Cansiliella servadeii percolating water on moonmilk, a speleothem formation in Grotta della Foos, Italy. Results from analyses of stable isotopes of carbon and nitrogen suggest that acquires and assimilates dissolved allochthonous organic carbon, inorganic nitrogen, and possibly phosphorus and other nutrients from the microbial fauna associated with moonmilk.

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Eogenetic Caves In Conglomerate: An Example From Udin Boršt, Slovenia, Matej Lipar, Mateja Ferk Jan 2011

Eogenetic Caves In Conglomerate: An Example From Udin Boršt, Slovenia, Matej Lipar, Mateja Ferk

International Journal of Speleology

Udin Boršt is a karstified terrace of carbonate rock, which is of fluvioglacial origin, and is situated in the north-western part of Slovenia. There are 15 registered caves, which have been interpreted as caves in conglomerate, while karst of Udin Boršt itself was interpreted as conglomerate karst, shallow karst or isolated karst. In this article, caves in Udin Boršt have been interpreted as eogenetic caves. Based on porosity and bedding material, different types of caves and cave passages have developed. Four general types of eogenetic caves found in Udin Boršt are; linear stream caves, shelter caves, breakdown caves and vadose …

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Fungal Communities On Speleothem Surfaces In Kartchner Caverns, Arizona, Usa., Michael J. Vaughan, Raina M. Maier, Barry M. Pryor Jan 2011

Fungal Communities On Speleothem Surfaces In Kartchner Caverns, Arizona, Usa., Michael J. Vaughan, Raina M. Maier, Barry M. Pryor

International Journal of Speleology

Kartchner Caverns, located near Benson, Arizona, USA, is an active carbonate cave that serves as the major attraction for Kartchner Caverns State Park. Low-impact development and maintenance have preserved prediscovery macroscopic cavern features and minimized disturbances to biological communities within the cave.. The goal of this study was to examine fungal diversity in Kartchner Caverns on actively-forming speleothem surfaces. Fifteen formations were sampled from five sites across the cave. Richness was assessed using standard culture-based fungal isolation techniques. A culture-independent analysis using denaturing gradient gel electrophoresis (DGGE) was used to assay evidence of community homogeneity across the cave through the …

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Cover: Volume 40, Issue 1 Jan 2011

Cover: Volume 40, Issue 1

International Journal of Speleology

No abstract provided.

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Table Of Contents Jan 2011

Table Of Contents

International Journal of Speleology

No abstract provided.

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Book Review: Advances In Research In Karst Media, Bartolomé Andreo Navarro Jan 2011

Book Review: Advances In Research In Karst Media, Bartolomé Andreo Navarro

International Journal of Speleology

No abstract provided.

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World Karst Science Reviews Jan 2011

World Karst Science Reviews

International Journal of Speleology

No abstract provided.

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Revisiting Three Minerals From Cioclovina Cave (Romania), Bogdan P. Onac, Herta S. Effenberger, Nathan C. Collins, Joe B. Kearns, Radu C. Breban Jan 2011

Revisiting Three Minerals From Cioclovina Cave (Romania), Bogdan P. Onac, Herta S. Effenberger, Nathan C. Collins, Joe B. Kearns, Radu C. Breban

International Journal of Speleology

Cioclovina Cave in Romania’s Southern Carpathians is a world-renowned cave site for its paleontological, anthropological, and mineralogical (type locality of ardealite) findings. To date, over 25 mineral species have been documented, some unusual for a cave environment. This paper presents details on the occurrence of collinsite [Ca2(Mg,Fe2+)(PO4)2·2H2O], atacamite [Cu22+Cl(OH)3], and kröhnkite [Na2Cu2+(SO4)2·2H2O] based on single-crystal X-ray diffraction, electron microprobe, stable isotope analyses, and scanning electron microscope imaging. This is the first reported occurrence of kröhnkite …

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Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, R. A.L. Wray Jan 2011

Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, R. A.L. Wray

International Journal of Speleology

This paper presents X-ray diffraction and SEM evidence for the formation of alunite, and possibly small quantities of natroalunite, within opal-A stalactites formed on quartz sandstone near Sydney in south-eastern, Australia. Alunite has been reported as a speleogenetic mineral from sediments within a number of caves around the world, but this is believed to be the first report of speleothemic alunite in opaline silica speleothems. Individual alunite crystals have not been visually identified, but SEM X-ray element mapping suggests the alunite has formed amongst kaolinite clay. Sedimentary alunite and natroalunite formation is usually associated with the reaction of sulphuric acid …

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