5,298 research outputs found

    Growth Improvement of Mung Bean (Vigna Radiata (L.) Wilczek R.) by Application of Mycofer and Phosphate Fertilizer

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    The objective of the research was to observe the effect of mycofer inoculation and the phosphate fertilizer on growth improvement of mung bean (Vigna radiata (L.) R. Wilczek). The research method used experimental method, which used randomize block design 2 x 7 factorial with 3 replications. The first factor was mycofer inoculation (M), which consisted of two levels, i.e. without mycofer inoculation (m0) and with mycofer inoculation (m1). The second factor was adding of phosphate fertilizer (P), which consisted of seven levels of doses, i.e. without adding of phosphate fertilizer (p0), 25 kg/ha (p1), 50 kg/ha (p2), 75 kg/ha (p3), 100 kg/ha (p4), 125 kg/ha (p5) and 150 kg/ha (p6). The observation parameter included the plant height, the leaf area, the dry weight, the number of pods, the seeds weight and the percentages of the root infection. The result showed that there was interaction between mycofer inoculation and the adding phosphate fertilizer to increase the plant height, the number of pods and the seeds weight. Phosphate fertilizer dose 75 kg/ha (p3) was the best dose for increasing the growth of mung bean plants inoculated mycofer on all parameters observed, except best phosphate fertilizers dose for the parameters of dry weight was 50 kg[1] / ha (p2)

    Growth of beam-plasma instabilities in the presence of background inhomogeneity

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    We explore how inhomogeneity in the background plasma number density alters the growth of electrostatic unstable wavemodes of beam plasma systems. This is particularly interesting for blazar-driven beam-plasma instabilities, which may be suppressed by inhomogeneities in the intergalactic medium as was recently claimed in the literature. Using high resolution Particle-In-Cell simulations with the SHARP code, we show that the growth of the instability is local, i.e., regions with almost homogeneous background density will support the growth of the Langmuir waves, even when they are separated by strongly inhomogeneous regions, resulting in an overall slower growth of the instability. We also show that if the background density is continuously varying, the growth rate of the instability is lower; though in all cases, the system remains within the linear regime longer and the instability is not extinguished. In all cases, the beam loses approximately the same fraction of its initial kinetic energy in comparison to the uniform case at non-linear saturation. Thus, inhomogeneities in the intergalactic medium are unlikely to suppress the growth of blazar-driven beam-plasma instabilities.Comment: 10 pages, 6 figures, Accepted by ApJ, comments welcom

    SHARP: A Spatially Higher-order, Relativistic Particle-in-Cell Code

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    Numerical heating in particle-in-cell (PIC) codes currently precludes the accurate simulation of cold, relativistic plasma over long periods, severely limiting their applications in astrophysical environments. We present a spatially higher-order accurate relativistic PIC algorithm in one spatial dimension, which conserves charge and momentum exactly. We utilize the smoothness implied by the usage of higher-order interpolation functions to achieve a spatially higher-order accurate algorithm (up to fifth order). We validate our algorithm against several test problems -- thermal stability of stationary plasma, stability of linear plasma waves, and two-stream instability in the relativistic and non-relativistic regimes. Comparing our simulations to exact solutions of the dispersion relations, we demonstrate that SHARP can quantitatively reproduce important kinetic features of the linear regime. Our simulations have a superior ability to control energy non-conservation and avoid numerical heating in comparison to common second-order schemes. We provide a natural definition for convergence of a general PIC algorithm: the complement of physical modes captured by the simulation, i.e., those that lie above the Poisson noise, must grow commensurately with the resolution. This implies that it is necessary to simultaneously increase the number of particles per cell and decrease the cell size. We demonstrate that traditional ways for testing for convergence fail, leading to plateauing of the energy error. This new PIC code enables us to faithfully study the long-term evolution of plasma problems that require absolute control of the energy and momentum conservation.Comment: 26 pages, 19 figures, discussion about performance is added, published in Ap

    Prediksi Harga Komoditi Jagung Menggunakan K-nn dan Particle Swarm Optimazation sebagai Fitur Seleksi

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    Jagung merupakan komponen terpenting pakan pabrikan di dunia, terutama di daerah tropis. Fluktuasi harga produk pertanian akan mengakibatkan ikut berfluktuasinya pendapatan yang diterima oleh petani dari hasil produksi pertanian mereka. Salah satu upaya untuk mengantisipasi terjadinya fluktuasi harga adalah dengan melakukan peramalan harga. Peramalan harga dimaksudkan untuk melakukan prakiraan/prediksi harga masa depan dalam kurun waktu tertentu, dengan hasil keluaran berupa harga masa depan. metode KNN dapat digunakan untuk memprediksi harga komoditi. Hasil eksperiment yang telah dilakukan peneliti menunjukkan bahwa algoritma K-NN berbasis Particle Swarm Optimazation lebih baik dibandingkan dengan algoritma K-NN tanpa fitur seleksi. Berdasarkan hasil penelitian nilai RMSE terendah terdapat pada K-Nearest Neighbor berbasis Particle Swarm Optimazation untuk data jagung dengan variabel periode 4 parameter k 7 nilai population 5 Max Of Generation 40 dengan nilai RMSE 0,0

    Importance of resolving the spectral support of beam-plasma instabilities in simulations

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    Many astrophysical plasmas are prone to beam-plasma instabilities. For relativistic and dilute beams, the {\it spectral} support of the beam-plasma instabilities is narrow, i.e., the linearly unstable modes that grow with rates comparable to the maximum growth rate occupy a narrow range of wave numbers. This places stringent requirements on the box-sizes when simulating the evolution of the instabilities. We identify the implied lower limits on the box size imposed by the longitudinal beam plasma instability, i.e., typically the most stringent condition required to correctly capture the linear evolution of the instabilities in multidimensional simulations. We find that sizes many orders of magnitude larger than the resonant wavelength are typically required. Using one-dimensional particle-in-cell simulations, we show that the failure to sufficiently resolve the spectral support of the longitudinal instability yields slower growth and lower levels of saturation, potentially leading to erroneous physical conclusion.Comment: 7 pages, 9 figures, accepted by Ap

    Uniform Diagonalization Theorem for Complexity Classes of Promise Problems including Randomized and Quantum Classes

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    Diagonalization in the spirit of Cantor's diagonal arguments is a widely used tool in theoretical computer sciences to obtain structural results about computational problems and complexity classes by indirect proofs. The Uniform Diagonalization Theorem allows the construction of problems outside complexity classes while still being reducible to a specific decision problem. This paper provides a generalization of the Uniform Diagonalization Theorem by extending it to promise problems and the complexity classes they form, e.g. randomized and quantum complexity classes. The theorem requires from the underlying computing model not only the decidability of its acceptance and rejection behaviour but also of its promise-contradicting indifferent behaviour - a property that we will introduce as "total decidability" of promise problems. Implications of the Uniform Diagonalization Theorem are mainly of two kinds: 1. Existence of intermediate problems (e.g. between BQP and QMA) - also known as Ladner's Theorem - and 2. Undecidability if a problem of a complexity class is contained in a subclass (e.g. membership of a QMA-problem in BQP). Like the original Uniform Diagonalization Theorem the extension applies besides BQP and QMA to a large variety of complexity class pairs, including combinations from deterministic, randomized and quantum classes.Comment: 15 page
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