Volcanism And Evolution Of The Early And Middle Jurassic Toodoggone Formation, Toodoggone Mining District, British Columbia

The Toodoggone Formation in Toodoggone River map area, north-central British Columbia, is an Early and Middle Jurassic time-stratigraphic Hazelton Group unit. Detailed mapping defined six subaerial lithostratigraphic members in the zeolite metamorphic facies. The High-K (3.1% K{dollar}\sb2{dollar}O at 57.5% SiO{dollar}\sb2{dollar}), calc alkaline latite and dacite volcanics are characterized by {dollar}\pm{dollar} sanidine - quartz - biotite - hornblende phenocysts. Basalt and rhyolite occur only as late dykes. Toodoggone strata occupy an elongate volcanic depression; they unconformably overlie submarine, arc volcanic and sedimentary rocks of the Permian Asitka and Late Triassic Takla Groups, and are capped unconformably by continental, Late Cretaceous clastic rocks of the Sustut Group.;Potassium-argon dates from the four volcanic members show two discrete cycles of volcanism. Shallow marine clastic rocks with middle to upper Toarcian fossils were deposited locally during the lull between cycles. The lower cycle (204 Ma to 197 Ma) began with widespread plateau-forming eruptions of dacite ash-flows, which are in part synchronous and superseded by latite flows and lahars that built stratovolcanoes. Possible comagmatic granodiorite and quartz monozonite plutons were emplaced during this period. The upper cycle began by 189 Ma with mainly dacite air-fall deposits. It culminated at about 182 Ma with voluminous outpourings of ash-flow tuffs and accompanying asymmetric collapse that produced the Central Toodoggone Depression.;The Toodoggone Formation is interpreted to record island arc magmatism. This arc magmatism resembles modern continent margin arc successions both in style and composition, hence it is believed that a thick, continent-like substrate underlies the Toodoggone area. The Toodoggone arc segment may be east-facing and related to steep, oblique westward subduction with a protracted history of intra-arc extension and shallow crustal subsidence. Extension and magmatism in Toodoggone map area is strikingly similar to large-scale extension and volcanic-sedimentary events in the McConnell Creek and Hazelton areas. This suggests consistent Jurassic tectonic evolution in these areas within a common, east-facing island arc developed along the east margin of the allochthonous Stikine terrane

Luis Mateo Díez: Las palabras de la vida

Review of: Luis Mateo Díez. Las palabras de la vida. Madrid, Temas de Hoy, 2000, 221 pp

Large-Scale Vented Deflagration Tests

PresentationThis paper presents results from a test program carried out to determine the peak deflagration pressure achieved within a congested enclosure vented through one wall of the enclosure. The industry standard in the United States for predicting the peak pressure developed in a vented deflagration is the National Fire Protection Association's Standard on Explosion Protection by Deflagration Venting (NFPA 68). The NFPA 68 (2013 edition) vent area correlation accounts for varying degrees of congestion if the ratio of the obstacle surface area (Aobs) to that of the enclosure (As) is greater than 0.4 (i.e., Ar = Aobs/As > 0.4). The tests described in this paper were performed using an obstacle array with an Ar ratio of less than 0.4. These tests were conducted in a rig with a 48-foot width, 24-foot depth, and 12-foot height. The rig was enclosed with solid walls, roof, and floor, allowing for venting through one of the long walls (i.e., 48-foot by 12-foot). The venting face of the rig was sealed with a 6 mil (0.15 mm) thick plastic vapor barrier to allow for the formation of a near-stoichiometric propane-air mixture. The flammable gas cloud was ignited near the center of the rear wall. Steel vent panels (20-gauge, 2 lbm/ft2 ) were installed over the plastic vapor barrier using explosion relief fasteners. The vent panels were configured to release at 0.3 psig; vent panel restraint devices were not utilized. The congestion inside the rig was provided by a regular array of vertical cylinders (2-inch schedule 40 pipe and 2-inch outer diameter cylinders) giving area and volume blockage ratios (ABR and VBR) of 4.9% and 2.2%, respectively, within the congestion array. The obstacle to enclosure surface area ratio (Ar) for this obstacle array pattern is 0.3 with the array extended throughout the rig, which is less than the critical value to account for congestion in the NFPA 68 correlation. Four series of tests were conducted with varying vent parameters, flammable gas cloud sizes, and congestion levels. Baseline tests were performed with the congestion array and flammable gas cloud extending throughout the rig without vent panels present (i.e., vapor barrier only). The second test series included the addition of vent panels for the same congestion pattern as that employed for the baseline tests. The third test series utilized a flammable gas cloud which filled only the back half of the rig. For the fourth test series, the congestion array only occupied 1⁄4 of the rig. The peak pressures and impulses for each test series are provided, along with pressure histories internal and external to the rig for selected tests. The steel vent panel throw distance is also provided as a function of internal peak pressure. The test data were compared with the predictions of the vent area correlations provided in NFPA 68. For all but the fourth test series (i.e., congestion array occupying 1⁄4 of the rig), the average internal peak pressures were approximately a factor of 2 larger than those predicted by NFPA 68

Comparison of Large-Scale Vented Deflagration Tests to CFD Simulations for Partially Congested Enclosures

PresentationThis paper presents a comparison between the results from a test program carried out to characterize the blast load environment within BakerRisk’s Deflagration Load Generator (DLG) test rig, and predictions made using the FLACS computational fluid dynamics (CFD) code. The test data was also compared to internal peak pressure predictions made using the National Fire Protection Association’s Standard on Explosion Protection by Deflagration Venting (NFPA 68) [1]. The purpose of these tests was to provide data for comparison with standard methods used to predict internal blast loads in a vented deflagration. The tests also provided a characterization of the internal DLG blast load environment for equipment qualification testing. The DLG test rig is 48 feet wide × 24 feet deep × 12 feet tall and is enclosed by three solid walls, a roof, and floor, with venting through one of the long walls (i.e., 48-foot by 12-foot). During testing, the venting face of the rig was sealed with a 6 mil (0.15 mm) thick plastic vapor barrier to allow for the formation of a near-stoichiometric propane-air mixture throughout the rig. The flammable gas cloud was ignited near the center of the rear wall. Congestion inside the rig was provided by a regular array of vertical cylinders (2-inch outer diameter) that occupied the rear half of the rig; the front half of the rig was uncongested (i.e., as would be the case for equipment qualification testing). Forty-three pressure transducers were deployed internal and external to the rig to measure blast pressure histories. Three series of tests were conducted with congestion levels varying from an area blockage ratio (ABR) of 11% in Test Series A to ABR values of 7.6% and 4.2%, respectively, in Test Series B and C. The obstacle-to-enclosure surface area ratio (Ar), a perameter used within the NFPA 68 correlations to quantify congestion, was equal to 0.45, 0.32, and 0.17 for test series A, B and C, respectively. The peak pressures and impulses for each test are provided, along with pressure histories internal and external to the rig for selected tests. Comparisons of the test data t

Review of methods used by chiropractors to determine the site for applying manipulation

Background: With the development of increasing evidence for the use of manipulation in the management of musculoskeletal conditions, there is growing interest in identifying the appropriate indications for care. Recently, attempts have been made to develop clinical prediction rules, however the validity of these clinical prediction rules remains unclear and their impact on care delivery has yet to be established. The current study was designed to evaluate the literature on the validity and reliability of the more common methods used by doctors of chiropractic to inform the choice of the site at which to apply spinal manipulation. Methods: Structured searches were conducted in Medline, PubMed, CINAHL and ICL, supported by hand searches of archives, to identify studies of the diagnostic reliability and validity of common methods used to identify the site of treatment application. To be included, studies were to present original data from studies of human subjects and be designed to address the region or location of care delivery. Only English language manuscripts from peer-reviewed journals were included. The quality of evidence was ranked using QUADAS for validity and QAREL for reliability, as appropriate. Data were extracted and synthesized, and were evaluated in terms of strength of evidence and the degree to which the evidence was favourable for clinical use of the method under investigation. Results: A total of 2594 titles were screened from which 201 articles met all inclusion criteria. The spectrum of manuscript quality was quite broad, as was the degree to which the evidence favoured clinical application of the diagnostic methods reviewed. The most convincing favourable evidence was for methods which confirmed or provoked pain at a specific spinal segmental level or region. There was also high quality evidence supporting the use, with limitations, of static and motion palpation, and measures of leg length inequality. Evidence of mixed quality supported the use, with limitations, of postural evaluation. The evidence was unclear on the applicability of measures of stiffness and the use of spinal x-rays. The evidence was of mixed quality, but unfavourable for the use of manual muscle testing, skin conductance, surface electromyography and skin temperature measurement. Conclusions: A considerable range of methods is in use for determining where in the spine to administer spinal manipulation. The currently published evidence falls across a spectrum ranging from strongly favourable to strongly unfavourable in regard to using these methods. In general, the stronger and more favourable evidence is for those procedures which take a direct measure of the presumptive site of care– methods involving pain provocation upon palpation or localized tissue examination. Procedures which involve some indirect assessment for identifying the manipulable lesion of the spine–such as skin conductance or thermography–tend not to be supported by the available evidence.https://doi.org/10.1186/2045-709X-21-3