Effects of percentage of blockage and flameholder downstream counterbores on lean combustion limits of premixed, prevaporized propane-air mixture

Lean combustion limits were determined for a premixed prevaporized propane air mixture with flat plate flame stabilizers. Experiments were conducted in a constant area flame tube combustor utilizing flameholders of varying percentages of blockage and downstream counterbores. Combustor inlet air velocity at ambient conditions was varied from 4 to 9 meters per second. Flameholders with a center hole and four half holes surrounding it were tested with 63, 73, and 85 percent blockage and counterbore diameters of 112 and 125 percent of the thru hole diameter, in addition to the no counterbore configuration. Improved stability was obtained by using counterbore flameholders and higher percentages of blockage. Increases in mixture velocity caused the equivalence ratio at blowout to increase in all cases

Tetraquark bound states in a constituent quark model and the nature of the a_0(980) and f_0(980)

In this work we study tetraquark bound states in the framework of the constituent quark model of Ref. [2], which has been used for the description of non-strange two- and three-baryon systems and later on applied to the hadron spectra.Comment: Contribution to the MESON 2002 Workshop. Krakow 24-28 May 200

Temperature chaos in 3D Ising Spin Glasses is driven by rare events

Temperature chaos has often been reported in literature as a rare-event driven phenomenon. However, this fact has always been ignored in the data analysis, thus erasing the signal of the chaotic behavior (still rare in the sizes achieved) and leading to an overall picture of a weak and gradual phenomenon. On the contrary, our analysis relies on a large-deviations functional that allows to discuss the size dependencies. In addition, we had at our disposal unprecedentedly large configurations equilibrated at low temperatures, thanks to the Janus computer. According to our results, when temperature chaos occurs its effects are strong and can be felt even at short distances.Comment: 5 pages, 5 figure

Dual regimes of ion migration in high repetition rate femtosecond laser inscribed waveguides

Ion migration in high repetition rate femtosecond laser inscribed waveguides is currently being reported in different optical glasses. For the first time we discuss and experimentally demonstrate the presence of two regimes of ion migration found in laser written waveguides. Regime-I, corresponds to the initial waveguide formation mainly via light element migration (in our case atomic weight < 31u), whereas regime-II majorly corresponds to the movement of heavy elements. This behavior brings attention to a problem which has never been analyzed before and that affects laser written active waveguides in which active ions migrate changing their local spectroscopic properties. The migration of active ions may in fact detune the pre-designed optimal values of active photonic devices. This paper experimentally evidences this problem and provides solutions to avert it.Comment: 4 pages, 5 figure

Studi Penggunaan Antibiotik tanpa Resep di Kabupaten Manggarai dan Manggarai Barat – NTT

Penggunaan antibiotik yang relatif tinggi menimbulkan beragam masalah dan merupakan ancaman global bagi kesehatan terutama dalam hal resistensi antibiotik. Selain berdampak pada morbiditas dan mortalitas, juga memberi dampak negatif terhadap ekonomi dan sosial yang sangat tinggi. Tujuan penelitian ini untuk menengetahui penggunaan antibiotik tanpa resep dokter di Kabupaten Manggarai dan Manggarai Barat. Penelitian ini bersifat non eksperimental dengan pengambilan sampel secara purposive menggunakan quota sampling. Data yang dianalisis meliputi tingkat kesadaran terhadap penggunaan antibiotik dan perilaku yang mempengaruhi penggunaan antibiotik tanpa resep dokter. Dari hasil penelitian didapatkan semua pasien (108 pasien) cenderung pernah menggunakan antibiotik tanpa resep dokter dan tingkat kesadaran pasien masih rendah. Perilaku pasien terkait penggunaan antibiotik tanpa resep dokter: Antibiotik yang paling sering dibeli dalam pelayanan tanpa resep dokter adalah Amoxicillin, jenis penyakit yang mayoritas diobati pasien dengan antibiotik adalah gejala flu, alasan pasien dalam menggunakan antibiotik tanpa resep adalah karena penggunaan antibiotik terdahulu memberikan hasil yang baik. Sedangkan ditinjau dari segi biaya 55.56% pasien (60 pasien) menjawab uang bukan masalah namun 44.44% (48 pasien) menjawab karena masalah keuangan. Dari 60 pasien yang menjawab uang bukan masalah, 73.33% (44 pasien) diantaranya menjawab pengobatan terdahulu memberikan hasil yang baik sehingga bila digunakan untuk penyakit yang serupa hasilnya sama

Probabilistic Bounds on the Length of a Longest Edge in Delaunay Graphs of Random Points in d-Dimensions

Motivated by low energy consumption in geographic routing in wireless networks, there has been recent interest in determining bounds on the length of edges in the Delaunay graph of randomly distributed points. Asymptotic results are known for random networks in planar domains. In this paper, we obtain upper and lower bounds that hold with parametric probability in any dimension, for points distributed uniformly at random in domains with and without boundary. The results obtained are asymptotically tight for all relevant values of such probability and constant number of dimensions, and show that the overhead produced by boundary nodes in the plane holds also for higher dimensions. To our knowledge, this is the first comprehensive study on the lengths of long edges in Delaunay graphsComment: 10 pages. 2 figures. In Proceedings of the 23rd Canadian Conference on Computational Geometry (CCCG 2011). Replacement of version 1106.4927, reference [5] adde