PENGEMBANGAN SENSOR GETAR ADXL335 SEBAGAI PETUNJUK PERAWATAN MESIN BUBUT HORISONTAL

Perkembangan teknologi komunikasi saat ini sangat pesat seiring kemajuan jaman dan meningkatnya kebutuhan manusia. Pemikiran untuk memanfaatkan sumber daya dengan efisien, membuat inovasi dan perkembangan teknologi pun terus berkembang. Pemanfaatan teknologi yang dikembangkan berdasarkan ilmu pengetahuan telah menyebabkan perubahan dan peralihan teknologi yang akhirnya memudahkan manusia menyelesaikan banyak persoalan. Teknologi komunikasi merupakan contoh teknologi peralihan yang ikut berkembang, karena sistem komunikasi tidak lagi mengenal batas serta memungkinkan dilakukan secara wireless.  Komunikasi kabel dan wireless dapat diimplementasikan pada sesama komputer atau komputer dengan mesin tertentu untuk keperluan monitoring dan analisa. Komponen yang dianalisa berhubungan dengan maintenance, yaitu umur komponen menggunakan jaringan kabel maupun wireless. Salah satu perilaku benda yang dapat dimonitoring adalah getaran Mesin bubut Horisontal pada Laboratorium Teknik Mesin. Penggunaan mesin bubut oleh mahasiswa terkadang tidak memperhatikan gejala kerusakan komponen, misalnya laher mesin. Akibatnya kualitas luaran dari benda kerja yang diolah menjadi kurang bagus. Dengan metode eksperimen telah dikembangkan sensor getar berbasis mikrokontroler menggunakan ADXL335, dimulai dengan identifikasi komponen, perancangan sensor, pemograman, kalibrasi dan penentuan kondisi ideal getaran. Kondisi ideal adalah sebuah nilai getaran dalam batasan tertentu ketika mesin masih baru atau terkalibrasi. Dalam penelitian ini nilai ideal adalah -0.002 s/d +0.002. Komponen mesin dinyatakan aus ketika output getaran melewati nilai ideal. Hasil penelitian menunjukkan bahwa sensor dapat membaca getaran mesin dan dimonitoring pada komputer. Komponen yang aus dapat diketahui ketika getaran mesin melewati nilai ideal dan suara beep berbunyi, sehingga para teknisi dapat mengambil tindakan perawatan dan hasil praktek mahasiswa juga lebih baik

Pengembangan Pintu Air Irigasi Pintar Berbasis Arduino untuk Daerah Irigasi Manikin

In general, irrigation watergates placed in the Manikin Irrigation Area is supporting tools for agricultural activities that implement a primary–secondary–tertiary channel system. Manikin irrigation watergate is made of iron plates with the certain size which is operated by a move up/down or rotation. This mechanism has led the dissatisfaction service problems in farmers. This study has developed smart irrigation watergate based on Arduino by replacing the lifter/rotator part using DC motor that works automatically based on the Real-time Clock sensor. This sensor sends the data time to Arduino and used as the reference to open or close the watergate. The study used a design method includes interconnecting realtime clock sensors and Arduino, build the programming control, build the DC system on watergates and interconnection to control systems and testing. The test results show that the irrigation watergate moves up and move down every 2 hours based on the data time from the real-time clock, works with a 12-hour time format and operating on 2.7-ampere current

A composite HII region luminosity function in H alpha of unprecedented statistical weight

Context. Statistical properties of HII region populations in disk galaxies yield important clues to the physics of massive star formation. Aims. We present a set of HII region catalogues and luminosity functions for a sample of 56 spiral galaxies in order to derive the most general form of their luminosity function. Methods. HII region luminosity functions are derived for individual galaxies which, after photometric calibration, are summed to form a total luminosity function comprising 17,797 HII regions from 53 galaxies. Results. The total luminosity function, above its lower limit of completeness, is clearly best fitted by a double power law with a significantly steeper slope for the high luminosity portion of the function. This change of slope has been reported in the literature for individual galaxies, and occurs at a luminosity of log L = 38.6\pm0.1 (L in erg/s) which has been termed the Stromgren luminosity. A steep fall off in the luminosity function above log L = 40 is also noted, and is related to an upper limit to the luminosities of underlying massive stellar clusters. Detailed data are presented for the individual sample galaxies. Conclusions. The luminosity functions of HII regions in spiral galaxies show a two slope power law behaviour, with a significantly steeper slope for the high luminosity branch. This can be modelled by assuming that the high luminosity regions are density bounded, though the scenario is complicated by the inhomogeneity of the ionized interstellar medium. The break, irrespective of its origin, is of potential use as a distance indicator for disc galaxies.Comment: Accepted for publication as a Letter in Astronomy & Astrophysics. Latex with postscript figures. Online-only tables and figures are included in this preprint. The HII region catalogues for 56 galaxies will be published electronically on the CDS but are available also on request from the author

Study of direct current motor power requirement for manikin smart irrigation systems

Manikin Irrigation Area (I.A) has ± 3000 ha of the area, utilizes the water source from the Tefmo Dam and distributes to the Primary-Secondary-Tertiary channels with controlled by watergates that operated by lift. This mechanism has resulted in jealousy and squabbles in farmer groups because of the inequality distribution that ultimately decreases crop production. The development of Microcontroller Technology has changed the Watergate model into an automated system based on certain parameters and algorithms. One of that being developed is the smart irrigation system based on Arduino at Manikin I.A that regulates the water to land based on the time from the Real-Time Clock sensor and uses Direct Current (DC) motor as a driver to watergate. While it may work, but the system has not considered the power requirement of DC motor when the water flows in the maximum discharge and pressure affecting the motor. This study examines the power requirement of an ideal DC motor for smart watergate in 5 open channels in Manikin I.A. Based on the open channel standard parameters, a total load measurement is performed when the water given speed (V) and pressure (p) then converted to energy. The study results that on 5 different open channels in Manikin I.A, with 0.30 m3/s maximum water discharge and 7.56 m/s2 flow rate, a watergate control requires DC motor that has 35 to 43 Watt power (39,4 Watt average power) or 3 to 3.5 Ampere current (3,26 Ampere average Current) in order to 24-hours work

Magneto-infrared modes in InAs-AlSb-GaSb coupled quantum wells

We have studied a series of InAs/GaSb coupled quantum wells using magneto-infrared spectroscopy for high magnetic fields up to 33T within temperatures ranging from 4K to 45K in both Faraday and tilted field geometries. This type of coupled quantum wells consists of an electron layer in the InAs quantum well and a hole layer in the GaSb quantum well, forming the so-called two dimensional electron-hole bilayer system. Unlike the samples studied in the past, the hybridization of the electron and hole subbands in our samples is largely reduced by having narrower wells and an AlSb barrier layer interposed between the InAs and the GaSb quantum wells, rendering them weakly hybridized. Previous studies have revealed multiple absorption modes near the electron cyclotron resonance of the InAs layer in moderately and strongly hybridized samples, while only a single absorption mode was observed in the weakly hybridized samples. We have observed a pair of absorption modes occurring only at magnetic fields higher than 14T, which exhibited several interesting phenomena. Among which we found two unique types of behavior that distinguishes this work from the ones reported in the literature. This pair of modes is very robust against rising thermal excitations and increasing magnetic fields alligned parallel to the heterostructures. While the previous results were aptly explained by the antilevel crossing gap due to the hybridization of the electron and hole wavefunctions, i.e. conduction-valence Landau level mixing, the unique features reported in this paper cannot be explained within the same concept. The unusual properties found in this study and their connection to the known models for InAs/GaSb heterostructures will be disccused; in addition, several alternative ideas will be proposed in this paper and it appears that a spontaneous phase separation can account for most of the observed features

PENGEMBANGAN SENSOR PARKIR BERBASIS ARDUINO DAN RFID PADA LAHAN PARKIR KENDARAAN RODA 2 POLITEKNIK NEGERI KUPANG

Pengembangan sistem parkir pintar berbasis Arduino dan RFId ini dibuat untuk memberikan solusi masalah pengaturan parkir kendaraan roda 2 di Gedung Auditorium Politeknik Negeri Kupang dan mekanisme pengaturannya yang masih konvensional sehingga memaksimalkan lahan parkir yang tersedia. Sistem bekerja secara otomatis, membaca blok parkir yang kosong dan mengijinkan akses kendaraan roda 2. Sistem dikembangkan menggunakan Arduino Mega sebagai central processing secara optimal bersama beberapa modul sensor yaitu RFId, photodioda dan LCD 16x2 untuk menampilkan informasi. Dengan metode perancangan, sistem parkir pintar RFId dikembangkan melalui 2 tahapan, yaitu merancang interkoneksi komponen perangkat keras sistem dan melakukan pemograman untuk menjalankan perangkat keras. Cara kerja sistem dimulai ketika sensor cahaya membaca blok parkir menggunakan sensor cahaya dan memberikan informasi melalui display LCD 16x2 tentang ada atau tidaknya blok parkir yang kosong. Jika ada, maka akses masuk kendaraan diberikan ketika identifikasi RFId diterima. Jika tidak, maka akses masuk tidak diberikan. Seluruh proses masuk dan keluar diuji dengan metode 0 1 pada 4 blok parkir. Hasil pengujian menunjukkan bahwa sensor RFId memberikan akses hanya jika salah satu atau lebih blok parkir masih kosong dan tidak memberi akses ketika seluruh blok parkir penuh (1 1 1 1 ). Kata kunci: Sensor Parkir, RFId, Arduino, ATMEGA32

How covariant is the galaxy luminosity function?

We investigate the error properties of certain galaxy luminosity function (GLF) estimators. Using a cluster expansion of the density field, we show how, for both volume and flux limited samples, the GLF estimates are covariant. The covariance matrix can be decomposed into three pieces: a diagonal term arising from Poisson noise; a sample variance term arising from large-scale structure in the survey volume; an occupancy covariance term arising due to galaxies of different luminosities inhabiting the same cluster. To evaluate the theory one needs: the mass function and bias of clusters, and the conditional luminosity function (CLF). We use a semi-analytic model (SAM) galaxy catalogue from the Millennium run N-body simulation and the CLF of Yang et al. (2003) to explore these effects. The GLF estimates from the SAM and the CLF qualitatively reproduce results from the 2dFGRS. We also measure the luminosity dependence of clustering in the SAM and find reasonable agreement with 2dFGRS results for bright galaxies. However, for fainter galaxies, L<L*, the SAM overpredicts the relative bias by ~10-20%. We use the SAM data to estimate the errors in the GLF estimates for a volume limited survey of volume V~0.13 [Gpc/h]^3. We find that different luminosity bins are highly correlated: for L<L* the correlation coefficient is r>0.5. Our theory is in good agreement with these measurements. These strong correlations can be attributed to sample variance. For a flux-limited survey of similar volume, the estimates are only slightly less correlated. We explore the importance of these effects for GLF model parameter estimation. We show that neglecting to take into account the bin-to-bin covariances can lead to significant systematic errors in best-fit parameters.Comment: 19 pages, 12 figures. Accepted for publication in MNRAS. Refs updated; Fig 6 added; Figs 7 and 10 improve

A composite H region luminosity function in Hα of unprecedented statistical weight

ABSTRACT Context. Statistical properties of H region populations in disk galaxies yield important clues to the physics of massive star formation. Aims. We present a set of H region catalogues and luminosity functions for a sample of 56 spiral galaxies in order to derive the most general form of their luminosity function. Methods. H region luminosity functions are derived for individual galaxies which, after photometric calibration, are summed to form a total luminosity function comprising 17,797 H regions from 53 galaxies. Results. The total luminosity function, above its lower limit of completeness, is clearly best fitted by a double power law with a significantly steeper slope for the high luminosity portion of the function. This change of slope has been reported in the literature for individual galaxies, and occurs at a luminosity of log L = 38.6 ± 0.1 (L in erg s −1 ) which has been termed the Strömgren luminosity. A steep fall off in the luminosity function above log L = 40 is also noted, and is related to an upper limit to the luminosities of underlying massive stellar clusters. Detailed data are presented for the individual sample galaxies. Conclusions. The luminosity functions of H regions in spiral galaxies show a two slope power law behaviour, with a significantly steeper slope for the high luminosity branch. This can be modelled by assuming that the high luminosity regions are density bounded, though the scenario is complicated by the inhomogeneity of the ionized interstellar medium. The break, irrespective of its origin, is of potential use as a distance indicator for disc galaxies

Decorrelating the Power Spectrum of Galaxies

It is shown how to decorrelate the (prewhitened) power spectrum measured from a galaxy survey into a set of high resolution uncorrelated band-powers. The treatment includes nonlinearity, but not redshift distortions. Amongst the infinitely many possible decorrelation matrices, the square root of the Fisher matrix, or a scaled version thereof, offers a particularly good choice, in the sense that the band-power windows are narrow, approximately symmetric, and well-behaved in the presence of noise. We use this method to compute band-power windows for, and the information content of, the Sloan Digital Sky Survey, the Las Campanas Redshift Survey, and the IRAS 1.2 Jy Survey.Comment: 11 pages, including 8 embedded PostScript figures. Minor changes to agree with published versio

Spectral Classification and Luminosity Function of Galaxies in the Las Campanas Redshift Survey

We construct a spectral classification scheme for the galaxies of the Las Campanas Redshift Survey (LCRS) based on a principal component analysis of the measured galaxy spectra. We interpret the physical significance of our six spectral types and conclude that they are sensitive to morphological type and the amount of active star formation. In this first analysis of the LCRS to include spectral classification, we estimate the general luminosity function, expressed as a weighted sum of the type-specific luminosity functions. In the R-band magnitude range of -23 < M <= -16.5, this function exhibits a broad shoulder centered near M = -20, and an increasing faint-end slope which formally converges on an alpha value of about -1.8 in the faint limit. The Schechter parameterization does not provide a good representation in this case, a fact which may partly explain the reported discrepancy between the luminosity functions of the LCRS and other redshift catalogs such as the Century Survey (Geller et al. 1997). The discrepancy may also arise from environmental effects such as the density-morphology relationship for which we see strong evidence in the LCRS galaxies. However, the Schechter parameterization is more effective for the luminosity functions of the individual spectral types. The data show a significant, progressive steepening of the faint-end slope, from alpha = +0.5 for early-type objects, to alpha = -1.8 for the extreme late-type galaxies. The extreme late-type population has a sufficiently high space density that its contribution to the general luminosity function is expected to dominate fainter than M = -16. We conclude that an evaluation of type-dependence is essential to any assessment of the general luminosity function.Comment: 21 pages (LaTeX), 7 figures (Postscript). To appear in the Astrophysical Journal. The discussion of environmental dependence of luminosity functions has been shortened; the material from the earlier version now appears in a separate manuscript (astro-ph/9805197