344 research outputs found

    Analisis Kelayakan Investasi Penambahan Mesin Frais Baru Pada CV. Xyz

    Full text link
    The rapid development of technology makes the world of industry must follow its development. Application of technology is expected to improve the production process so it can be produce a quality product. On the industrial manufacture of printing machines in CV XYZ, the machines have been used almost more than 20 years. There are indications that those machines passed the age lifetime. The alternatives that have been used during this time are the replacement of defective parts. Researchers wanted to compare these alternatives with the addition of a new milling machine. It required the addition of investment feasibility analysis of a new machine. The approximate period of 10 years and interest rates of 15% by using the NPV, the addition of milling machines attract Rp 461.201 million compared to replacement of defective parts of Rp 211.227 million. In contrast to the PBP and PI, the replacement of defective parts that are still ahead for 1 year 4 months and 4.2 compared to the addition of a new milling machine for 2 years and 1 month and 2.56. That can be concluded within 10 years, the alternative replacement of defective parts is still better than the addition of a new milling machine. However, for long-term investment it may be an alternative addition of a new milling machine more interesting

    Characterization of Fluctuations of Impedance and Scattering Matrices in Wave Chaotic Scattering

    Full text link
    In wave chaotic scattering, statistical fluctuations of the scattering matrix SS and the impedance matrix ZZ depend both on universal properties and on nonuniversal details of how the scatterer is coupled to external channels. This paper considers the impedance and scattering variance ratios, VRzVR_z and VRsVR_s, where VRz=Var[Zij]/{Var[Zii]Var[Zjj]}1/2VR_z=Var[Z_{ij}]/\{Var[Z_{ii}]Var[Z_{jj}] \}^{1/2}, VRs=Var[Sij]/{Var[Sii]Var[Sjj]}1/2VR_s=Var[S_{ij}]/\{Var[S_{ii}]Var[S_{jj}] \}^{1/2}, and Var[.]Var[.] denotes variance. VRzVR_z is shown to be a universal function of distributed losses within the scatterer. That is, VRzVR_z is independent of nonuniversal coupling details. This contrasts with VRsVR_s for which universality applies only in the large loss limit. Explicit results are given for VRzVR_z for time reversal symmetric and broken time reversal symmetric systems. Experimental tests of the theory are presented using data taken from scattering measurements on a chaotic microwave cavity.Comment: 6 pages, 5 figures, updated with referees' comment

    PEMANFAATAN LIMBAH SABUT KELAPA SEBAGAI PRODUK UNGGULAN LOKAL

    Get PDF
    Coir is a fairly large part of the coconut fruit, which is 35% of the total weight of the fruit. Coconut coir consists of fibers and cork that connect one fiber to another. Fiber is a valuable part of coir. Each coconut contains 525 grams of fiber (75% of coir), and 175 grams of cork (25% of coir). The classification of fiber based on its origin is that coconut coir fiber itself is a type of natural fiber derived from the coconut plant, namely the fruit. Coconut coir when decomposed will produce coir fiber (cocofibre) and coir powder (cococoir). The purpose of the activity is to improve the understanding and skills of farmers around the Darul Iman Islamic Boarding School in Tanjung Sari Village, Natar District, to utilize coconut coir waste into products that have local competitiveness, namely brooms and doormats. The activities are carried out by learning by doing with the stages of socialization, counseling, direct implementation direct practice, and evaluation.Sabut kelapa merupakan bagian yang cukup besar dari buah kelapa, yaitu 35 % dari berat keseluruhan buah. Sabut kelapa terdiri dari serat dan gabus yang menghubungkan satu serat dengan serat lainnya. Serat adalah bagian yang berharga dari sabut. Setiap butir kelapa mengandung serat 525 gram (75% dari sabut), dan gabus 175 gram (25% dari sabut). Klasifikasi serat berdasarkan asalnya bahwa serat sabut kelapa sendiri merupakan jenis serat alami yang berasal dari tumbuhan kelapa yaitu buahnya. Sabut kelapa jika diurai akan menghasilkan serat sabut (cocofibre) dan serbuk sabut (cococoir). Tujuan kegiatan adalah meningkatkan pemahaman dan keterampilan para petani di sekitar Ponpes Darul Iman Desa Tanjung Sari Kecamatan Natar untuk memanfaatkan limbah sabut kelapa menjadi produk yang memiliki daya saing lokal yaitu sapu dan keset. kegiatan dilakukan dengan learning by doing dengan tahapan sosialisasi, penyuluhan, pelaksanaan langsung/praktik langsung, dan evaluasi

    Chaotic Scattering in the Regime of Weakly Overlapping Resonances

    Full text link
    We measure the transmission and reflection amplitudes of microwaves in a resonator coupled to two antennas at room temperature in the regime of weakly overlapping resonances and in a frequency range of 3 to 16 GHz. Below 10.1 GHz the resonator simulates a chaotic quantum system. The distribution of the elements of the scattering matrix S is not Gaussian. The Fourier coefficients of S are used for a best fit of the autocorrelation function if S to a theoretical expression based on random--matrix theory. We find very good agreement below but not above 10.1 GHz

    Measuring the Lyapunov exponent using quantum mechanics

    Full text link
    We study the time evolution of two wave packets prepared at the same initial state, but evolving under slightly different Hamiltonians. For chaotic systems, we determine the circumstances that lead to an exponential decay with time of the wave packet overlap function. We show that for sufficiently weak perturbations, the exponential decay follows a Fermi golden rule, while by making the difference between the two Hamiltonians larger, the characteristic exponential decay time becomes the Lyapunov exponent of the classical system. We illustrate our theoretical findings by investigating numerically the overlap decay function of a two-dimensional dynamical system.Comment: 9 pages, 6 figure

    Pesticide Leaching from Agricultural Fields with Ridges and Furrows

    Get PDF
    In the evaluation of the risk of pesticide leaching to groundwater, the soil surface is usually assumed to be level, although important crops like potato are grown on ridges. A fraction of the water from rainfall and sprinkler irrigation may flow along the soil surface from the ridges to the furrows, thus bringing about an extra load of water and pesticide on the furrow soil. A survey of the literature reveals that surface-runoff from ridges to furrows is a well-known phenomenon but that hardly any data are available on the quantities of water and pesticide involved. On the basis of a field experiment with additional sprinkler irrigation, computer simulations were carried out with the Pesticide Emission Assessment at Regional and Local scales model for separate ridge and furrow systems in a humic sandy potato field. Breakthrough curves of bromide ion (as a tracer for water flow) and carbofuran (as example pesticide) were calculated for 1-m depth in the field. Bromide ion leached comparatively fast from the furrow system, while leaching from the ridge system was slower showing a maximum concentration of about half of that for the furrow system. Carbofuran breakthrough from the furrow system began about a month after application and increased steadily to substantial concentrations. Because the transport time of carbofuran in the ridge soil was much longer, no breakthrough occurred in the growing season. The maximum concentration of carbofuran leaching from the ridge–furrow field was computed to be a factor of six times as high as that computed for the corresponding level field. The study shows that the risk of leaching of pesticides via the furrow soil can be substantially higher than that via the corresponding level field soil

    Effect of Cerbera Manghas Biodiesel on Diesel Engine Performance

    Get PDF
    In order to reduce the use of fossil fuel without interfering the availability of food crop, Cerbera manghas biodiesel has been studied as potential renewable fuel. This study investigated Cerbera manghas biodiesel as a replacement for pure petro-diesel and palm oil biodiesel produced in Indonesia. The investigation result indicates that Cerbera manghas biodiesel fuel has a lower density, kinematic viscosity, sulfur content, color (lighter), water content, distillation point compared to pure petro-diesel and palm oil biodiesel. Higher flash point and cetane index value in Cerbera manghas biodiesel were also discovered. The study investigated further the effect of biodiesel derived from Cerbera manghas biodiesel compared with pure petro-diesel and palm oil biodiesel in a single cylinder diesel engine. The study suggested that Cerbera manghas biodiesel has better engine performance (fuel consumption, brake mean effective pressure, thermal efficiency, torque, and power) compared to pure petro-diesel and palm oil biodiesel. The utilization of Cerbera manghas biodiesel gave better engine performance output compared to pure petro-diesel and palm oil biodiesel. This study supported the viability of Cerbera manghas biodiesel to be implemented as an alternative diesel fuel without interfering food resources or requiring additional modification to the existing diesel engine

    Signatures of the correlation hole in total and partial cross sections

    Full text link
    In a complex scattering system with few open channels, say a quantum dot with leads, the correlation properties of the poles of the scattering matrix are most directly related to the internal dynamics of the system. We may ask how to extract these properties from an analysis of cross sections. In general this is very difficult, if we leave the domain of isolated resonances. We propose to consider the cross correlation function of two different elastic or total cross sections. For these we can show numerically and to some extent also analytically a significant dependence on the correlations between the scattering poles. The difference between uncorrelated and strongly correlated poles is clearly visible, even for strongly overlapping resonances.Comment: 25 pages, 13 Postscript figures, typos corrected and references adde

    Strain-induced partially flat band, helical snake states, and interface superconductivity in topological crystalline insulators

    Get PDF
    Topological crystalline insulators in IV-VI compounds host novel topological surface states consisting of multi-valley massless Dirac fermions at low energy. Here we show that strain generically acts as an effective gauge field on these Dirac fermions and creates pseudo-Landau orbitals without breaking time-reversal symmetry. We predict the realization of this phenomenon in IV-VI semiconductor heterostructures, due to a naturally occurring misfit dislocation array at the interface that produces a periodically varying strain field. Remarkably, the zero-energy Landau orbitals form a flat band in the vicinity of the Dirac point, and coexist with a network of snake states at higher energy. We propose that the high density of states of this flat band gives rise to interface superconductivity observed in IV-VI semiconductor multilayers at unusually high temperatures, with non-BCS behavior. Our work demonstrates a new route to altering macroscopic electronic properties to achieve a partially flat band, and paves the way for realizing novel correlated states of matter.Comment: Accepted by Nature Physic

    Resonance trapping and saturation of decay widths

    Full text link
    Resonance trapping appears in open many-particle quantum systems at high level density when the coupling to the continuum of decay channels reaches a critical strength. Here a reorganization of the system takes place and a separation of different time scales appears. We investigate it under the influence of additional weakly coupled channels as well as by taking into account the real part of the coupling term between system and continuum. We observe a saturation of the mean width of the trapped states. Also the decay rates saturate as a function of the coupling strength. The mechanism of the saturation is studied in detail. In any case, the critical region of reorganization is enlarged. When the transmission coefficients for the different channels are different, the width distribution is broadened as compared to a chi_K^2 distribution where K is the number of channels. Resonance trapping takes place before the broad state overlaps regions beyond the extension of the spectrum of the closed system.Comment: 18 pages, 8 figures, accepted by Phys. Rev.
    • …
    corecore