344 research outputs found
Analisis Kelayakan Investasi Penambahan Mesin Frais Baru Pada CV. Xyz
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
In wave chaotic scattering, statistical fluctuations of the scattering matrix
and the impedance matrix 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, and
, where ,
, and denotes
variance. is shown to be a universal function of distributed losses
within the scatterer. That is, is independent of nonuniversal coupling
details. This contrasts with for which universality applies only in the
large loss limit. Explicit results are given for 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
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
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
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
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
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
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
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
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.
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