623 research outputs found

    Coal cleaning by froth flotation

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    A number of experiments were conducted to determine the flotation characteristics of Iowa coals in which various conditions were applied to study the effect of different parameters such as frother dosage, oily collectors, pyrite depressants, and various combinations of these reagents. Flotation tests were also conducted with Appalachian coals for comparison;Iowa coals did not respond as well to froth flotation as Appalachian coals. Although Iowa coal floated very slowly and incompletely with only a frother (methyl isobutyl carbinol or MIBC), it floated rapidly when a large dosage of an oily collector (No. 200 LLS fuel oil) was employed in addition. No. 1 fuel oil was not nearly as effective as a collector for this application. The order of addition of flotation reagents appeared very important for achieving a high recovery of Iowa coal;Appalachian coals floated rapidly with only a frother (methyl isobutyl carbinol) or an alkaline solution. A small amount of an oily collector increased the recovery of Appalachian coals significantly. The results of these flotation experiments showed that little mineral matter was removed when a high recovery was achieved. A microscopic analysis of Appalachian coal used in these experiments showed that much of the mineral matter was incompletely liberated from the coal particles. And, the use of ultrasonics did seem to improve mineral matter liberation;Bubble-particle attachment was studied from a theoretical view point. This study showed that the mechanism of attachment differs depending on the relative size of bubbles and particles. When small bubbles adhere to a flat or slightly curved surface of a particle, the bubble size was found to be determined by the contact angle between the bubble and the particle. The study indicated that micro-bubbles could separate mineral matter from low rank coal more selectively than macro-bubbles could. When a micro-bubble flotation technique was employed to float Appalachian coal, it produced a cleaner coal product than conventional macro-bubble flotation;A general kinetic model was proposed to represent the rate of flotation of coal. For two Appalachian coals, the model successfully represented the flotation kinetics of uniformly sized coal. The proposed model also represented well the flotation kinetics of coal consisting of two sizes of particles

    The first record of a frogfish, Fowlerichthys scriptissimus (Antennariidae, Lophiiformes), from Korea

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    Abstract This is the first report of Fowlerichthys scriptissimus (Lophiiformes, Antennariidae) from Korea. A single specimen (291.0 mm SL) was collected off the coast of Jejudo Island by gill net on 28 March 2012 and identified with morphological and molecular approaches. The specimen is characterized by having all five pelvic fin rays bifurcate and possessing 20 vertebrae, 13 pectoral-fin rays, and a basidorsal ocellus on the side of the body. This species is distinguishable from other Korean taxa by the number of pectoral fin rays, the bifurcate form of the pelvic rays, and the vertebral count. We add this species to the Korean fish fauna and suggest new Korean names, “Byeol-ssin-beng-i-sok” and “Byeol-ssin-beng-i” for the genus and species, respectively

    Information-Energy Equivalence in Qigong: Reviewing Dossey and Schwartz’s “Therapeutic Intent/Healing Bibliography of Research” in Light of Pang Ming’s Three Levels Theory of Matter

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    The paper “Therapeutic Intent/Healing Bibliography of Research”[1], together with relevant studies involving the effects of external qi healing found on the PubMed database from January 2000 to July 2012, were reviewed from the point of view of therapeutic intent mechanism and healing intent specificity. From an oriental medicine perspective, therapeutic intent is a form of external qi healing. Research into therapeutic intent has met significant resistance, primarily because there is no obvious theoretical model to account for these phenomena. By applying the Three Levels Theory of Matter as proposed by Zhineng Qigong founder, Pang Ming, this article points the way to such a possible mechanis

    TickTock: Detecting Microphone Status in Laptops Leveraging Electromagnetic Leakage of Clock Signals

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    We are witnessing a heightened surge in remote privacy attacks on laptop computers. These attacks often exploit malware to remotely gain access to webcams and microphones in order to spy on the victim users. While webcam attacks are somewhat defended with widely available commercial webcam privacy covers, unfortunately, there are no adequate solutions to thwart the attacks on mics despite recent industry efforts. As a first step towards defending against such attacks on laptop mics, we propose TickTock, a novel mic on/off status detection system. To achieve this, TickTock externally probes the electromagnetic (EM) emanations that stem from the connectors and cables of the laptop circuitry carrying mic clock signals. This is possible because the mic clock signals are only input during the mic recording state, causing resulting emanations. We design and implement a proof-of-concept system to demonstrate TickTock's feasibility. Furthermore, we comprehensively evaluate TickTock on a total of 30 popular laptops executing a variety of applications to successfully detect mic status in 27 laptops. Of these, TickTock consistently identifies mic recording with high true positive and negative rates.Comment: 18 pages, 27 figures, ACM CCS'22 conferenc

    Global Characteristics of the Correlation and Time Lag Between Solar and Ionospheric Parameters in the 27-day Period

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    The 27-day variations of topside ionosphere are investigated using the in-situ electron density measurements from the CHAMP planar Langmuir probe and GRACE K-band ranging system. As the two satellite systems orbit at the altitudes of approx. 370 km and approx. 480 km, respectively, the satellite data sets are greatly valuable for examining the electron density variations in the vicinity of F2-peak. In a 27-day period, the electron density measurements from the satellites are in good agreements with the solar flux, except during the solar minimum period. The time delays are mostly 1-2 day and represent the hemispherical asymmetry. The globally-estimated spatial patterns of the correlation between solar flux and in-situ satellite measurements show poor correlations in the (magnetic) equatorial region, which are not found from the ground measurements of vertically-integrated electron content. We suggest that the most plausible cause for the poor correlation is the vertical movement of ionization due to atmospheric dynamic processes that is not controlled by the solar extreme ultraviolet radiation

    Ice Velocity Mapping of Ross Ice Shelf, Antarctica by Matching Surface Undulations Measured by Icesat Laser Altimetry

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    We present a novel method for estimating the surface horizontal velocity on ice shelves using laser altimetrydata from the Ice Cloud and land Elevation Satellite (ICESat; 20032009). The method matches undulations measured at crossover points between successive campaigns

    Rapid Dye Regeneration Mechanism of Dye-Sensitized Solar Cells

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    During the light-harvesting process of dye-sensitized solar cells (DSSCs), the hole localized on the dye after the charge separation yields an oxidized dye, D^+. The fast regeneration of D^+ using the redox pair (typically the I^–/I_(3)^– couple) is critical for the efficient DSSCs. However, the kinetic processes of dye regeneration remain uncertain, still promoting vigorous debates. Here, we use molecular dynamics simulations to determine that the inner-sphere electron-transfer pathway provides a rapid dye regeneration route of ∌4 ps, where penetration of I^− next to D^+ enables an immediate electron transfer, forming a kinetic barrier. This explains the recently reported ultrafast dye regeneration rate of a few picoseconds determined experimentally. We expect that our MD based comprehensive understanding of the dye regeneration mechanism will provide a helpful guideline in designing TiO_2−dye−electrolyte interfacial systems for better performing DSSCs

    Multi-Hop Routing-Based Optimization of the Number of Cluster-Heads in Wireless Sensor Networks

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    Wireless sensor networks require energy-efficient data transmission because the sensor nodes have limited power. A cluster-based routing method is more energy-efficient than a flat routing method as it can only send specific data for user requirements and aggregate similar data by dividing a network into a local cluster. However, previous clustering algorithms have some problems in that the transmission radius of sensor nodes is not realistic and multi-hop based communication is not used both inside and outside local clusters. As energy consumption based on clustering is dependent on the number of clusters, we need to know how many clusters are best. Thus, we propose an optimal number of cluster-heads based on multi-hop routing in wireless sensor networks. We observe that a local cluster made by a cluster-head influences the energy consumption of sensor nodes. We determined an equation for the number of packets to send and relay, and calculated the energy consumption of sensor networks using it. Through the process of calculating the energy consumption, we can obtain the optimal number of cluster-heads in wireless sensor networks

    Post-radiation Piriformis Syndrome in a Cervical Cancer Patient -A Case Report-

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    The piriformis syndrome is a condition allegedly attributable to compression of the sciatic nerve by the piriformis muscle. Recently, magnetic resonance neurography and electrophysiologic study have helped to diagnose piriformis syndrome. High dose radiotherapy could induce acute and delayed muscle damage. We had experienced piriformis syndrome with fatty atrophy of piriformis muscle after radiotherapy for recurrent cervical cancer
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