250 research outputs found

    Rumput Laut (Ulva lactuca) sebagai Pakan Substitusi Sapi Bali Sapihan di Musim Kemarau dengan Level Energi yang Berbeda

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    Penelitian dilakukan untuk mengetahui kualitas dan pengaruh rumput laut (Ulva lactuca) sebagai pakan substitusi untuk sapi Bali sapihan di musim kemarau dengan level energi yang berbeda. Penelitian dilakukan dua tahap yaitu perlakuan in vitro untuk mengetahui level ideal pemberian tepung U. lactuca dengan perlakuan RA = hay rumput alam; RAK = RA+konsentrat; RAKU5 =RAK+U. lactuca 5%; RAKU10= RAK+U. lactuca 10%; RAKU15= RAK+U. lactuca 15%; RAKU20= RAK+U. lactuca 20%. Tahap kedua menggunakan rancangan Bujur Sangkar Latin dengan perlakuan R1 = EM 7,3 MJ, R2 = EM 8 MJ dan R3 = EM 8,7 MJ. Hasil penelitian menunjukkan bahwa level ideal pemberian yang dapat digunakan adalah 15% dengan nilai kecernaan bahan kering dan bahan organik tertinggi yaitu 77,79 dan 78,56%.  Tahap kedua yaitu pemberian tepung U. lactuca sebanyak 15% dari total ransum dengan level energy yang berbeda untuk sembilan ekor sapi Bali sapihan dengan tujuan mengetahui tingkat konsumsi dan kecernaan dengan perlakuan EM R1= 7,3 MJ; R= 8 MJ; dan R3= 8,7 MJ. Hasil penelitian menunjukkan bahwa substitusi tepung U. lactuca sebanyak 15% tidak memberikan pengaruh negatif terhadap konsumsi dan kecernaan. Hasil sidik ragam menunjukkan ransum dengan energi 8 MJ memiliki konsumsi dan kecernaan yang sama dengan energi 8,7 MJ namun lebih tinggi dibandingkan dengan ransum  berenergi 7,3 MJ

    An Alternative Approach to the Fracture Toughness of Dual Phase Steels

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    In this study, the effects of ferrite morphology and of ferrite volume fraction on the mechanical properties and the fracture toughness values ( ) KIc of dual phase steels were investigated. The fracture toughness values were determined using an approach that was different from the standard one. A homogenization heat treatment was applied to the steels. Two different starting microstructures were then obtained by either the full annealing of or the quenching of the steels from austenite before applying intercritical annealing to the steels in the austenite region. After this process, dual phase steels with two types of morphology, coarse and fine, were obtained with 40, 20, and 10% ferrite volume fractions, depending on the starting microstructure. Tempered specimens with 10% ferrite exhibited improved fracture toughness values compared with those of the other steels.Исследуется влияние морфологии структуры феррита и его объемного содержания на механические свойства и вязкость разрушения двухфазных сталей. Для определения значений вязкости разрушения использовали не стандартный, а альтернативный подход. Стали подвергали гомогенизирующей термообработке. Путем полного отжига или закалки сталей из аустенитного состояния до применения докритического отжига в аустенитной области получены две различные исходные микроструктуры. Получены двухфазные стали с двумя типами морфологии (крупно- и мелкозернистая) с 40-, 20- и 10%-ным объемным содержанием феррита в зависимости от исходной микроструктуры. Отпущенные образцы с 10%-ным объемным содержанием феррита имели более высокие значения вязкости разрушения по сравнению с таковыми других образцов из этих сталейДосліджується вплив морфології структури фериту та його об’ємного вмісту на механічні властивості і в’язкість руйнування двофазних сталей. Для визначення значень в’язкості руйнування використовували не стандартний, а альтернативний підхід. Сталі піддавали гомогенізуючій термообробці. Шляхом повного відпалу або загартування сталей з аустенітного стану до використання докритичного відпалу в аустенітній області отримано дві різні початкові мікроструктури. Отримано двофазні сталі з двома типами морфології (великоі дрібнозеренна) з 40-, 20- і 10%-ним об’ємним вмістом фериту в залежності від початкової мікроструктури. Відпущені зразки з 10%-ним об’ємним вмістом фериту мали більш високі значення в’язкості руйнування порівняно з такими інших зразків із цих сталей

    Young Double Slit Interference Effects at Quantum Level

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    The currently accepted model for quantum interference resulting from the emission of electron waves from two scattering centers induced by either light or charged particle impact is analogous to Young\u27s emission of two light waves from two slits. In this work we show that this simple classical wave model is incomplete and that there is a more complicated quantum interference pattern for low energy ionization caused by electron impact

    High-Speed High Effiency Large Area Resonant Cavity Enhanced p-I-n Photodiodes for Multimode Fiber Communications

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    Cataloged from PDF version of article.In this letter, we report AlGaAs–GaAs p-i-n photodiodes with a 3-dB bandwidth in excess of 10 GHz for devices as large as 60- m diameter. Resonant cavity enhanced photodetection is employed to improve quantum efficiency, resulting in more than 90% peak quantum efficiency at 850 nm

    Theoretical and Experimental Investigation of (e, 2e) Ionization of Argon 3p in Asymmetric Kinematics at Intermediate Energy

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    The field of electron-impact ionization of atoms, or (e, 2e), has provided significant detailed information about the physics of collisions. For ionization of hydrogen and helium, essentially exact numerical methods have been developed which can correctly predict what will happen. For larger atoms, we do not have theories of comparable accuracy. Considerable attention has been given to ionization of inert gases and, of the inert gases, argon seems to be the most difficult target for theory. There have been several studies comparing experiment and perturbative theoretical approaches over the last few decades, and generally qualitative but not quantitative agreement is found for intermediate energy incident electrons. Recently a nonperturbative method, the B-spline R-matrix (BSR) method, was introduced which appears to be very promising for ionization of heavier atoms. We have recently performed an experimental and theoretical investigation for ionization of argon, and we found that, although the BSR gave reasonably good agreement with experiment, there were also some cases of significant disagreement. The previous study was performed for 200-eV incident electrons and ejected electron energies of 15 and 20 eV. The purpose of the present work is to extend this study to a much larger range of ejected electron energies (15-50 eV) to see if theory gets better with increasing energy as would be expected for a perturbative calculation. The experimental results are compared with both the BSR and two different perturbative calculations

    Theoretical and Experimental Investigation of (e, 2e) Ionization of Argon 3p in Asymmetric Kinematics at Intermediate Energy

    Get PDF
    The field of electron-impact ionization of atoms, or (e, 2e), has provided significant detailed information about the physics of collisions. For ionization of hydrogen and helium, essentially exact numerical methods have been developed which can correctly predict what will happen. For larger atoms, we do not have theories of comparable accuracy. Considerable attention has been given to ionization of inert gases and, of the inert gases, argon seems to be the most difficult target for theory. There have been several studies comparing experiment and perturbative theoretical approaches over the last few decades, and generally qualitative but not quantitative agreement is found for intermediate energy incident electrons. Recently a nonperturbative method, the B-spline R-matrix (BSR) method, was introduced which appears to be very promising for ionization of heavier atoms. We have recently performed an experimental and theoretical investigation for ionization of argon, and we found that, although the BSR gave reasonably good agreement with experiment, there were also some cases of significant disagreement. The previous study was performed for 200-eV incident electrons and ejected electron energies of 15 and 20 eV. The purpose of the present work is to extend this study to a much larger range of ejected electron energies (15-50 eV) to see if theory gets better with increasing energy as would be expected for a perturbative calculation. The experimental results are compared with both the BSR and two different perturbative calculations

    High-speed >90% quantum-efficiency p–i–n photodiodes with a resonance wavelength adjustable in the 795–835 nm range

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    Cataloged from PDF version of article.We report GaAs/AlGaAs-based high-speed, high-efficiency, resonant cavity enhanced p–i–nphotodiodes. The devices were fabricated by using a microwave-compatible fabrication process. By using a postprocess recess etch, we tuned the resonance wavelength from 835 to 795 nm while keeping the peak efficiencies above 90%. The maximum quantum efficiency was 92% at a resonance wavelength of 823 nm. The photodiode had an experimental setup-limited temporal response of 12 ps. When the system response is deconvolved, the 3 dB bandwidth corresponds to 50 GHz, which is in good agreement with our theoretical calculations. © 1999 American Institute of Physic

    Palaeozoic-Recent geological development and uplift of the Amanos Mountains (S Turkey) in the critically located northwesternmost corner of the Arabian continent

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    <p>We have carried out a several-year-long study of the Amanos Mountains, on the basis of which we present new sedimentary and structural evidence, which we combine with existing data, to produce the first comprehensive synthesis in the regional geological setting. The ca. N-S-trending Amanos Mountains are located at the northwesternmost edge of the Arabian plate, near the intersection of the African and Eurasian plates. Mixed siliciclastic-carbonate sediments accumulated on the north-Gondwana margin during the Palaeozoic. Triassic rift-related sedimentation was followed by platform carbonate deposition during Jurassic-Cretaceous. Late Cretaceous was characterised by platform collapse and southward emplacement of melanges and a supra-subduction zone ophiolite. Latest Cretaceous transgressive shallow-water carbonates gave way to deeper-water deposits during Palaeocene-Eocene. Eocene southward compression, reflecting initial collision, resulted in open folding, reverse faulting and duplexing. Fluvial, lagoonal and shallow-marine carbonates accumulated during Late Oligocene(?)-Early Miocene, associated with basaltic magmatism. Intensifying collision during Mid-Miocene initiated a foreland basin that then infilled with deep-water siliciclastic gravity flows. Late Miocene-Early Pliocene compression created mountain-sized folds and thrusts, verging E in the north but SE in the south. The resulting surface uplift triggered deposition of huge alluvial outwash fans in the west. Smaller alluvial fans formed along both mountain flanks during the Pleistocene after major surface uplift ended. Pliocene-Pleistocene alluvium was tilted towards the mountain front in the west. Strike-slip/transtension along the East Anatolian Transform Fault and localised sub-horizontal Quaternary basaltic volcanism in the region reflect regional transtension during Late Pliocene-Pleistocene (<4 Ma).</p

    High-speed high-efficiency resonant cavity enhanced photodiodes

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    In this paper, we review our research efforts on RCE high-speed high-efficiency p-i-n and Schottky photodiodes. Using a microwave compatible planar fabrication process, we have designed and fabricated GaAs based RCE photodiodes. For RCE Schottky photodiodes, we have achieved a peak quantum efficiency of 50% along with a 3-dB bandwidth of 100 GHz. The tunability of the detectors via a recess etch is also demonstrated. For p-i-n type photodiodes, we have fabricated and tested widely tunable devices with near 100% quantum efficiencies, along with a 3-dB bandwidth of 50 GHz. Both of these results correspond to the fastest RCE photodetectors published in scientific literature
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