877 research outputs found

    The impacts of direct lightning bolt on the Ngo-Brazzaville line in Congo

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    The importance of line Ngo-Brazzaville (220 kV, 207 km) requires operators to avoid cuts that can increase the risk of instability. We see it is quite rare that a storm that occurs in areas crossed by this line will not cause triggering. We note that lightning discharges constitute the main causes of unscheduled power cuts on the electricity lines of Congo however, we ignore the peak values of voltage waves that result. In regions with high level keraunic like Congo, reducing insulation failures due to lightning is a concern in the management of overhead lines. This article clarifies the peak values of surges that can be reached on the electricity network, in order to enlighten the operators as for precautions to observe about the insulation coordination of protective equipment related to lightning. For these surgersquos calculations of atmospheric origin (case of lightning), we considered the Heidler function for modeling the wave of the lightning current. This methodology led us to specially treat the effects of directnbspnbsp lightning bolt that constitute the worst case because they generate most destructive shock wave that indirect thunderbolt

    Evidence of Twisting and Mixed-polarity Solar Photospheric Magnetic Field in Large Penumbral Jets: IRIS and Hinode Observations

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    A recent study using {\it Hinode} (SOT/FG) data of a sunspot revealed some unusually large penumbral jets that often repeatedly occurred at the same locations in the penumbra, namely at the tail of a penumbral filament or where the tails of multiple penumbral filaments converged. These locations had obvious photospheric mixed-polarity magnetic flux in \NaI\ 5896 Stokes-V images obtained with SOT/FG. Several other recent investigations have found that extreme ultraviolet (EUV)/X-ray coronal jets in quiet Sun regions (QRs), coronal holes (CHs) and near active regions (ARs) have obvious mixed-polarity fluxes at their base, and that magnetic flux cancellation prepares and triggers a minifilament flux-rope eruption that drives the jet. Typical QR, CH, and AR coronal jets are up to a hundred times bigger than large penumbral jets, and in EUV/X-ray images show clear twisting motion in their spires. Here, using IRIS \MgII\ k 2796 \AA\ SJ images and spectra in the penumbrae of two sunspots we characterize large penumbral jets. We find redshift and blueshift next to each other across several large penumbral jets, and interpret these as untwisting of the magnetic field in the jet spire. Using Hinode/SOT (FG and SP) data, we also find mixed-polarity magnetic flux at the base of these jets. Because large penumbral jets have mixed-polarity field at their base and have twisting motion in their spires, they might be driven the same way as QR, CH and AR coronal jets.Comment: 18 pages, 11 figures; to appear in Ap

    Evaluation of Two Commercially Available Cannabidiol Formulations for Use in Electronic Cigarettes

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    Since 24 states and the District of Columbia have legalized marijuana in some form, suppliers of legal marijuana have developed Cannabis sativa products for use in electronic cigarettes (e-cigarettes). Personal battery powered vaporizers, or e-cigarettes, were developed to deliver a nicotine vapor such that smokers could simulate smoking tobacco without the inherent pathology of inhaled tobacco smoke. The liquid formulations used in these devices are comprised of an active ingredient such as nicotine mixed with vegetable glycerin (VG) and/or propylene glycol (PG) and flavorings. A significant active ingredient of C. sativa, cannabidiol (CBD), has been purported to have anti-convulsant, anti-nociceptive, and anti-psychotic properties. These properties have potential medical therapies such as intervention of addictive behaviors, treatments for epilepsy, management of pain for cancer patients, and treatments for schizophrenia. However, CBD extracted from C. sativa remains a DEA Schedule I drug since it has not been approved by the FDA for medical purposes. Two commercially available e-cigarette liquid formulations reported to contain 3.3 mg/mL of CBD as the active ingredient were evaluated. These products are not regulated by the FDA in manufacturing or in labeling of the products and were found to contain 6.5 and 7.6 mg/mL of CBD in VG and PG with a variety of flavoring agents. Presently, while labeled as to content, the quality control of manufacturers and the relative safety of these products is uncertain

    The Effect of Electronic Cigarette User Modifications and E-liquid Adulteration on the Particle Size Profile of an Aerosolized Product

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    Electronic cigarettes (e-cigarettes) are an alternate nicotine delivery system that generate a condensation aerosol to be inhaled by the user. The size of the droplets formed in the aerosol can vary and contributes to drug deposition and ultimate bioavailability in the lung. The growing popularity of e-cigarette products has caused an increase in internet sources promoting the use of drugs other than nicotine (DOTNs) in e-cigarettes. The purpose of this study was to determine the effect of various e-cigarette and e-liquid modifications, such as coil resistance, battery voltage, and glycol and drug formulation, on the aerosol particle size. E-liquids containing 12 mg/mL nicotine prepared in glycol compositions of 100% propylene glycol (PG), 100% vegetable glycerin (VG), or 50:50 PG:VG were aerosolized at three voltages and three coil resistances. Methamphetamine and methadone e-liquids were prepared at 60 mg/mL in 50:50 PG:VG and all e-liquids were aerosolized onto a 10 stage Micro-Orifice Uniform Deposit Impactor. Glycol deposition correlated with drug deposition, and the majority of particles centered between 0.172–0.5 μm in diameter, representing pulmonary deposition. The 100% PG e-liquid produced the largest aerosol particles and the 100% VG and 50:50 PG:VG e-liquids produced ultra-fine particles \u3c0.3 μm. The presence of ultrafine particles indicates that drugs can be aerosolized and reach the pulmonary alveolar regions, highlighting a potential for abuse and risk of overdose with DOTNs aerosolized in an e-cigarette system

    Behavioral and Electrical Responses Associated with Exposure to Extreme Cold or Heat in the Salamander

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    Author Institution: Albers Biological Laboratory, Xavier University, and the Department of Anatomy, College of Medicine, University of Cincinnati, Cincinnati, Ohi

    Hi-C2.1 Observations of Solar Jetlets at Edges of Network Lanes

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    We present high resolution (0.2) high cadence (5s) extreme ultraviolet (EUV) observations of small-scale jetlet-like features and spicule-like features observed with NASAs High-resolution Coronal Imager2.1 (Hi-C) during its 5min observing span. We investigate the magnetic setting of 4 on-disk jetlets and 2 on-disk spicules by using high resolution 172A images from Hi-C and EUV images from Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and line-of-sight magnetograms from SDO/Helioseismic and Magnetic Imager (HMI). The jetlets and spicules are at edges of magnetic network lanes. From magnetograms co-aligned with the Hi-C and AIA images, we find that the jetlets stem from sites of likely flux cancelation between merging majority-polarity and weaker minority-polarity flux, but in contrast to larger jetlets observed by IRIS some do not show obvious enhanced brightenings at their base. Based on the similarity of these observations of approx. 4 obvious Hi-C small jetlets with our previous observations of 10 IRIS larger jetlets and approx. 30 coronal jets in quiet regions and coronal holes, we infer that flux cancelation is probably the essential process in the buildup and triggering of jetlets. Our observations suggest that network jetlet eruptions, large and small, are small-scale analogs of both larger-scale coronal jet eruptions and the still-larger-scale eruptions that makemajor CMEs. For simplicitywe will use termjetlets for jetlet-like features and spicules for spicule-like features

    Exploring EUV Spicules Using 304 Angstrom He II Data from SDO AIA

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    We present results from a statistical study of He II 304 Angstrom Extreme Ultraviolet (EUV) spicules at the limb of the Sun. We also measured properties of one macrospicule; macrospicules are longer than most spicules, and much broader in width than spicules. We use high-cadence (12 second) and high-resolution (0.6 arcseconds pixels) resolution data from the Atmospheric Imaging Array (AIA) instrument on the Solar Dynamic Observatory (SDO). All of the observed events occurred near the solar north pole, where quiet Sun or coronal hole environments ensued. We examined the maximum lengths, maximum rise velocities, and lifetimes of 33 Extreme Ultraviolet (EUV) spicules and the macrospicule. For the bulk of the Extreme Ultraviolet (EUV) spicules these quantities are, respectively, approximately 10,000-40,000 kilometers, 20-100 kilometers per second, and approximately 100- approximately 1000 seconds. For the macrospicule the corresponding quantities were respectively approximately 60,000 kilometers, approximately 130 kilometers per second, approximately 1800 seconds, which is typical of macrospicules measured by other workers. Therefore macrospicules are taller, longer-lived, and faster than most Extreme Ultraviolet (EUV) spicules. The rise profiles of both the spicules and the macrospicules match well a second-order ("parabolic" ) trajectory, although the acceleration was often weaker than that of solar gravity in the profiles fitted to the trajectories. Our macrospicule also had an obvious brightening at its base at birth, while such brightening was not apparent for the Extreme Ultraviolet (EUV) spicules. Most of the Extreme Ultraviolet (EUV) spicules remained visible during their descent back to the solar surface, although a small percentage of the spicules and the macrospicule faded out before falling back to the surface. Our sample of macrospicules is not yet large enough to determine whether their initiation mechanism is identical to that of Extreme Ultraviolet (EUV) spicules

    The Cause of Faint Coronal Jets from Emerging-Flux Regions in Solar Coronal Holes

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    Coronal jets are transient thin bursts of magnetically channeled solar material from the surface into the corona. They are brightest at their base, with a bright point (jet bright point, JBP) at an edge of the base. Early studies (Shibata et al. 1992) suggested that jets result from magnetic flux emergence: a small bipole emerges into unipolar ambient field, driving the jet and forming the JBP via interchange reconnection. More recent studies, using higher-cadence, higher-resolution, and broader wavelength coverage than before, show that prominent coronal jets are usually driven by a minifialment eruption (Sterling et al. 2015), and that, rather than flux emergence, flux cancelation usually prepares and triggers the eruption (Panesar et al. 2016). Here, we analyzed eight emerging flux regions to determine whether the emerging flux directly drove any coronal jets. We used EUV images from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) (in 304, 171, 211, 193, and 94 channels), and magnetograms from SDO/Helioseismic & Magnetic Imager (HMI). All eight regions produced jet-like features that were weak in intensity (faint jets), by which we mean they were so faint that we likely would not have identified them as jets had we initially searched for jets in AIA movies alone (as in, e.g., Panesar et al. 2016, Moore et al. 2013) without knowing whether the base was an emerging bipole. In seven of the eight regions, all jets (faint or prominent) erupted from locations where one leg of the emerging bipole was evidently canceling with an ambient opposite-polarity flux clump. The eighth case, the one that had the fastest flux emergence, possibly made faint jets by the flux-emergence mechanism, but these too might instead have resulted from flux cancelation

    Evidence from IRIS that Sunspot Large Penumbral Jets Spin

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    Recent observations from Hinode (SOT/FG) revealed the presence of large penumbral jets (widths 500 km, larger than normal penumbral microjets, which have widths < 400 km) repeatedly occurring at the same locations in a sunspot penumbra, at the tail of a filament or where the tails of several penumbral filaments apparently converge (Tiwari et al. 2016, ApJ). These locations were observed to have mixed-polarity flux in Stokes-V images from SOT/FG. Large penumbral jets displayed direct signatures in AIA 1600, 304, 171, and 193 channels; thus they were heated to at least transition region temperatures. Because large jets could not be detected in AIA 94 , whether they had any coronal-temperature plasma remains unclear. In the present work, for another sunspot, we use IRIS Mg II k 2796 slit jaw images and spectra and magnetograms from Hinode SOT/FG and SOT/SP to examine: whether penumbral jets spin, similar to spicules and coronal jets in the quiet Sun and coronal holes; whether they stem from mixed-polarity flux; and whether they produce discernible coronal emission, especially in AIA 94 images. The few large penumbral jets for which we have IRIS spectra show evidence of spin. If these have mixed-polarity at their base, then they might be driven the same way as coronal jets and CMEs

    Validation of lay‐administered mental health assessments in a large Army National Guard cohort

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    To report the reliability and validity of key mental health assessments in an ongoing study of the Ohio Army National Guard (OHARNG). The 2616 OHARNG soldiers received hour‐long structured telephone surveys including the post‐traumatic stress disorder (PTSD) checklist (PCV‐C) and Patient Health Questionnaire – 9 (PHQ‐9). A subset ( N  = 500) participated in two hour clinical reappraisals, using the Clinician‐Administered PTSD Scale (CAPS) and the Structured Clinical Interview for DSM (SCID). The telephone survey assessment for PTSD and for any depressive disorder were both highly specific [92% (standard error, SE 0.01), 83% (SE 0.02)] with moderate sensitivity [54% (SE 0.09), 51% (SE 0.05)]. Other psychopathologies assessed included alcohol abuse [sensitivity 40%, (SE 0.04) and specificity 80% (SE 0.02)] and alcohol dependence [sensitivity, 60% (SE 0.05) and specificity 81% (SE 0.02)].The baseline prevalence estimates from the telephone study suggest alcohol abuse and dependence may be higher in this sample than the general population. Validity and reliability statistics suggest specific, but moderately sensitive instruments. Copyright © 2014 John Wiley & Sons, Ltd .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106694/1/mpr1416.pd
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