296 research outputs found

    Image Text Search and Retrieval System

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    An imaging device comprising a flexible sensor attached to a control case. The flexible sensor provides both a source of illumination to the image being captured and a method of capturing the image. The method of capture comprises a field of reactors disbursed across the facial area of the sensor, the output of which produces a dot-pattern capture of the intended image which is passed to a storage device

    Mathematically gifted elementary students\u27 revisiting of Euler\u27s polyhedron theorem

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    This paper explores how the constructions of mathematically gifted fifth and sixth grade students using Euler’s polyhedron theorem compare to those of mathematicians as discussed by Lakatos (1976). Eleven mathematically gifted elementary school students were asked to justify the theorem, find counterexamples, and resolve conflicts between the theorem and counterexamples. The students provided two types of justification of the theorem. The solid figures suggested as counterexamples were categorized as 1) solids with curved surfaces, 2) solids made of multiple polyhedra sharing points, lines, or faces, 3) polyhedra with holes, and 4) polyhedra containing polyhedra. In addition to using the monster-barring method, the students suggested two new types of conjectures to resolve the conflicts between counterexamples and the theorem, the exception-baring method and the monster-adjustment method. The students’ constructions resembled those presented by mathematicians as discussed by Lakatos

    Modeling the shock-induced multiple reactions in a random bed of metallic granules in an energetic material

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    An investigation of shock–particle interactions in reactive flows is performed using an Eulerian hydrodynamic method with a hybrid particle level-set algorithm to handle the material interface dynamics. The analysis is focused on the meso- to macro-scale numerical modeling of a granular metalized explosive containing randomly distributed metal particles intended to enhance its blast effect. The reactive flow model is used for the cyclotrimethylene-trinitramine (RDX) component, while thermally induced deflagration kinetics describes the aerobic reaction of the metal particles. The complex interfacial algorithm, which uses aligned level sets to track deforming surface between multi materials and to generate the random shape of granule elements, is described for aluminized and copperized RDX. Then, the shock-induced collapse of metal particles embedded in the condensed phase domain of a high explosive is simulated. Both aluminized and copperized RDX are shown to detonate with a shock wave followed by the burning of the metal particles. The energy release and the afterburning behavior behind the detonating shock wave successfully identified the precursor that gave rise to the development of deflagration of the metal particles

    Analytical Study on the Performance Characteristics of a Liquid Injection Refrigeration Cycle.

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    A residential heat pump faced with reliability problems due to high compressor discharge temperature and lower performance at lower ambient temperatures. Many researchers have been trying to overcome this problem by applying vapor injection techniques. However, the application of the vapor injection cycle caused higher cost due to the increased components such as internal heat exchanger or flash tank. Liquid injection technique has merits of cost and cycle reliability due to refrigerant that discharged from the condenser was expanded and injected directly into the compressor. In this study, a simulation program for a liquid injection heat pump cycle was developed. The performance of the cycle was simulated using a mass and energy balances. The model was validated by comparing the predictions with measured data at various operating conditions. Based on the simulation results, cycle performance characteristics were discussed at various operating and compressor design conditions using the simulation program

    Validation Study of Kim's Sham Needle by Measuring Facial Temperature: An N-of-1 Randomized Double-Blind Placebo-Controlled Clinical Trial

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    Introduction. In 2008, Kim's sham needle was developed to improve the quality of double-blinded studies. The aim of this study is to validate Kim's sham needle by measuring facial temperature. Methods. We designed “N-of-1” trials involving 7 smokers. One session was composed of 2 stimulations separated by a 2 h washout period. Six sessions were applied daily for all subjects. Infrared thermal imaging was used to examine the effects of acupuncture (HT8, KI2) on facial temperature following smoking-induced decrease. Results. All subjects demonstrated decreased temperatures after sham needle treatment, but 5 of the 7 subjects showed increased temperatures after real needle treatment. 6 of the 7 subjects showed a significant difference (P < 0.05) between treatments with real and sham needles. Thus, the physiological stimulation of Kim's sham needle is different from that of a real needle, suggesting that Kim's sham needle is a potential inactive control intervention

    Translocation of the cyanobacterial toxin microcystin-LR into guttation drops of Triticum aestivum and remaining toxicity

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    Uptake of the commonly occurring cyanobacterial toxin microcystin-LR (MC-LR) into crop plants via spray irrigation has been demonstrated. As other hazardous compounds such as pesticides were shown to be transported within plants, it was essential to understand the transport and fate of MC-LR in plants and the risks posed to grazers and other consumers. Of specific interest was to investigate if MC-LR could be detected in guttation drops and the toxicity thereof. Triticum aestivum (wheat) seedlings were exposed to 100 μg L−1 MC-LR in two separate experiments during which guttation drops were collected at various time points. The plants of one experiment were sectioned to investigate MC-LR distribution to the various plant appendages via liquid chromatography-tandem mass spectrometry analysis. After exposure, MC-LR could be detected in the roots, stems, leaves, and the guttation drops. However, the guttation drops were not toxic to Daphnia. As the environmentally relevant toxin concentration used was not sufficient to promote mortality in Daphnia, the physiological effect in insects, which rely on guttation drops as a water source, remains unknown. Combined with other contaminants that insects may be exposed to, the additional MC-LR exposure could contribute to the overall toxicity through the “tears of death”.Peer reviewe

    Ageing affects microplastic toxicity over time: Effects of aged polycarbonate on germination, growth, and oxidative stress of Lepidium sativum

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    Plastic has been an environmental pollutant far longer than claimed by the first reports surfacing in 1979, meaning some plastic materials have been decaying in nature for decades. Nevertheless, the threat posed to biota is not fully understood, especially from aged microplastic. The question considered in this study was whether the adverse effects of new plastic differ from those of old plastic material. Therefore, the morphological and physiological effects on Lepidium sativum with exposure to both new and aged polycarbonate were considered against a known stressor leaching from polycarbonate with time, bisphenol-A. Exposure to new and short-term aged polycarbonate (up to 80 days) elicited the most severe effects such as germination inhibition, reduced seedling growth, decreased chlorophyll concentrations, and increased catalase activity. These adverse effects in L. sativum associated with polycarbonate exposure were reduced as a function of the ageing time applied to the polycarbonate. The chemical substances that lend new polycarbonate material its toxicity were likely leached with time during the ageing process. Based on the results obtained, temperature and humidity based artificial ageing significantly reduced the phytotoxicity of the microplastic particlesPeer reviewe
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