94 research outputs found

    Pop-Up Structures and the Fracture Pattern in the Balsam Lake Area, Southern Ontario

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    An examination of topographic lineaments detectable in Landsat TM images and measurement of joints in outcrop in the Balsam Lake area reveals a systematic bedrock fracture pattern with three principal sets oriented 091°, 027°, and 152°. The 027° trend is parallel to a major aeromagnetic anomaly, the Niagara-Pickering Linear Zone (NPLZ), which underlies the Balsam Lake area and is thought to mark the sub-Paleozoic continuation of the Proterozoic Central Metasedimentary Belt Boundary Zone (CMBBZ). Possible origins of the main joint sets due to Acadian (091° set), Alleghanian (152° set) and St. Lawrence rift system tectonics (091° and 027° sets) are discussed. En-echelon pop-up structures have a mean principal trend of 118°. They displace Lake Algonquin paleobeaches, suggesting formation less than 12,500 years ago. The orientation of the pop-up structures is subnormal to the current in situ maximum horizontal stress direction, SHmax (020°), and is parallel to members of the 091° joint set, indicating possible nuclea-tion on favourably-oriented pre-existing joints. These pop-ups are the only features in the Balsam Lake area with strong evidence for a neotectonic age.L'examen des linĂ©aments topographiques repĂ©rables sur les images Landsat (TM) et la mesure des diaclases dans un affleurement de la rĂ©gion de Balsam Lake rĂ©vĂšle la prĂ©sence d'un rĂ©seau de fractures dont l'orientation des trois principaux ensembles est 091°, 027° et 152°. La direction 027° est parallĂšle Ă  une anomalie aĂ©romagnĂ©tique majeure, la zone linĂ©aire Niagara-Pickering, prĂ©sente sous la rĂ©gion de Balsam Lake; on croit qu'elle identifie le prolongement sub-palĂ©ozoĂŻque de l'aire limite de la zone mĂ©ta-sĂ©dimentaire centrale protĂ©rozoĂŻque. On traite des origines possibles des principaux ensembles de fractures attribuables aux systĂšmes acadien (091°), allĂ©ghanien (152°) et du rift du Saint-Laurent (091 °et 027°). La direction des structures de soulĂšvement en Ă©chelon est de 118°. Elles ont dĂ©placĂ© des palĂ©o-plages du Lac Algonquin, indiquant ainsi une formation postĂ©rieure Ă  12 500 ans. L'orientation des structures de soulĂšvement est subnormale Ă  la direction de la contrainte horizontale maximale actuelle, SHmax(020°), et est parallĂšle Ă  des Ă©lĂ©ments de l'ensemble des fractures de direction 091°, montrant ainsi leur formation possible dans des fractures existantes bien orientĂ©es. Ces structures de soulĂšvement sont les seuls Ă©lĂ©ments de la rĂ©gion dĂ©montrant un Ăąge nĂ©otectonique.Eine Untersuchung der topographischen Lineamente die in Landsat TM-Bildern nachweisbar sind und Messungen der Fugen in den AufschlĂčssen des Balsam Lake-Gebiets lassen ein systematisches Bruchmuster des anstehenden Gesteins erkennen mit drei nach 091°, 027° und 152° ausgerichteten Haupteinheiten. Die Ausrichtung nach 027° ist parallel zu einer wichtigen aeromagnetischen Anomalie, der linearen Zone von Niagara-Pickering, die unter dem Balsam Lake-Gebiet liegt; man halt sie fur eine subpalĂ ozoische FortfĂčhrung des Grenz-bereichs der proterozoischen zentralen metasedimentĂ ren GĂčrtel-zone. Man diskutiert mĂŽgliche UrsprĂčnge der Hauptfugen-systeme, die auf die akadische (091° System), alleghanische (152° System) und Sankt-Lorenz-Spaltensystem Tektonik (091° und 027° System) zurĂčckgefĂčhrt werden. Die gestaffelten Hebungsstrukturen haben eine durchschnittliche Hauptrichtung von 118°. Sie haben PalĂ o-StrĂ nde vom Lake Algonquin versetzt, und weisen so auf eine Bildung vor weniger als 12,500 Jahren. Die Orientierung der Hebungsstrukturen ist subnormal zu der gegenwĂ rtigen maximalen horizontalen Stressrichtung, S"m" (020°) und parallel zu Elementen des 091° Fugen-systems, was auf ihre mĂŽgliche Bildung auf gĂčnstig orientierten schon vorhandenen Fugen weist. DiĂšse Hebungen sind die einzi-gen Strukturen im Balsm Lake-Gebiet, welche deutlich ein neotektonisches Alter belegen

    Sensor for monitoring plasma parameters

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    A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing hardware for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3, 45, and 90% N2 in Ar) at pressure 0.5-70 Pa and inductive power of 100 and 300 W. The results were compared to rotational temperature derived from the N2 emission at the (0,0) transition of the C - B system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N2*) that varied depending on conditions. A two-dimensional, two-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro- and nano-fabrication plasma processing, thus enabling the diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable tracking the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.Comment: Presented at the Photonics West conference, Lasers and Applications in Science and Technology, San Jose, CA, January 2004. This version gives a more detailed introduction on diode lasers as diagnostic tool for micro/nano-fabrication. A follow-up paper published in Plasma Sources Sci. Technol., v.13, 691-700 (2004) featured improvements in plasma simulatio

    Analytical Predictions for a Natural Spacing within Dyke Swarms

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    International audienceDykes often grow next to other dykes, evidenced by the widespread occurrence of dyke swarms that comprise many closely-spaced dykes. In giant dyke swarms, dykes are observed to maintain a finite spacing from their neighbors that is tens to hundreds of times smaller than their length. To date, mechanical models have not been able to clarify whether there exists an optimum, or natural spacing between the dykes. And yet, the existence of a natural spacing is at the heart of why dykes grow in swarms in the first place. Here we present and examine a mechanical model for the horizontal propagation of multiple, closely-spaced blade-like dykes in order to find energetically optimal dyke spacings associated with both constant pressure and constant influx magma sources. We show that the constant pressure source leads to an optimal spacing that is equal to the height of the blade-like dykes. We also show that the constant influx source leads to two candidates for an optimal spacing, one which is expected to be around 0.3 times the dyke height and the other which is expected to be around 2.5 times the dyke height. Comparison with measurements from dyke swarms in Iceland and Canada lend initial support to our predictions, and we conclude that dyke swarms are indeed expected to have a natural spacing between first generation dykes and that this spacing scales with, and is on the order of, the height of the blade-like dykes that comprise the swarm

    Structural Characteristics of Carbon Nanofibers for On-chip Interconnect Applications

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    In this letter, we compare the structures of plasma-enhanced chemical vapor deposition of Ni-catalyzed and Pd-catalyzed carbon nanofibers (CNFs) synthesized for on-chip interconnect applications with scanning transmission electron microscopy (STEM). The Ni-catalyzed CNF has a conventional fiberlike structure and many graphitic layers that are almost parallel to the substrate at the CNF base. In contrast, the Pd-catalyzed CNF has a multiwall nanotubelike structure on the sidewall spanning the entire CNF. The microstructure observed in the Pd-catalyzed fibers at the CNF-metal interface has the potential to lower contact resistance significantly, as our electrical measurements using current-sensing atomic force microscopy indicate. A structural model is presented based on STEM image analysis

    Magma plumbing systems: a geophysical perspective

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    Over the last few decades, significant advances in using geophysical techniques to image the structure of magma plumbing systems have enabled the identification of zones of melt accumulation, crystal mush development, and magma migration. Combining advanced geophysical observations with petrological and geochemical data has arguably revolutionised our understanding of, and afforded exciting new insights into, the development of entire magma plumbing systems. However, divisions between the scales and physical settings over which these geophysical, petrological, and geochemical methods are applied still remain. To characterise some of these differences and promote the benefits of further integration between these methodologies, we provide a review of geophysical techniques and discuss how they can be utilised to provide a structural context for and place physical limits on the chemical evolution of magma plumbing systems. For example, we examine how Interferometric Synthetic Aperture Radar (InSAR), coupled with Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) data, and seismicity may be used to track magma migration in near real-time. We also discuss how seismic imaging, gravimetry and electromagnetic data can identify contemporary melt zones, magma reservoirs and/or crystal mushes. These techniques complement seismic reflection data and rock magnetic analyses that delimit the structure and emplacement of ancient magma plumbing systems. For each of these techniques, with the addition of full-waveform inversion (FWI), the use of Unmanned Aerial Vehicles (UAVs) and the integration of geophysics with numerical modelling, we discuss potential future directions. We show that approaching problems concerning magma plumbing systems from an integrated petrological, geochemical, and geophysical perspective will undoubtedly yield important scientific advances, providing exciting future opportunities for the volcanological community

    Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial.

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    BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden

    Cruden's complete concordance : To the Old and New Testaments

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    Grand Rapids803 p ; 21 cm

    Cruden's Coplete Concordance : to the Old and New Testamnets

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    Michigan803 p.; 20 c
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