Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog

We complete construction of a catalog containing improved astrometry and new optical/infrared photometry for the vast majority of NLTT stars lying in the overlap of regions covered by POSS I and by the second incremental 2MASS release, approximately 44% of the sky. The epoch 2000 positions are typically accurate to 130 mas, the proper motions to 5.5 mas/yr, and the V-J colors to 0.25 mag. Relative proper motions of binary components are measured to 3 mas/yr. The false identification rate is ~1% for 11 < V < 18 and substantially less at brighter magnitudes. These improvements permit the construction of a reduced proper motion diagram that, for the first time, allows one to classify NLTT stars into main-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We in turn use this diagram to analyze the properties of both our catalog and the NLTT catalog on which it is based. In sharp contrast to popular belief, we find that NLTT incompleteness in the plane is almost completely concentrated in MS stars, and that SDs and WDs are detected almost uniformly over the sky DEC > -33 deg. Our catalog will therefore provide a powerful tool to probe these populations statistically, as well as to reliably identify individual SDs and WDs.Comment: 16 figures. We will make the revised NLTT publicly available on acceptance of the paper, or no later than July 18, 200

Classifying Luyten Stars Using An Optical-Infrared Reduced Proper Motion Diagram

We present a V-J reduced proper motion (RPM) diagram for stars in the New Luyten Two-Tenths (NLTT) catalog. In sharp contrast to the RPM diagram based on the original NLTT data, this optical-infrared RPM diagram shows distinct tracks for white dwarfs, subdwarfs, and main-sequence stars. It thereby permits the identification of white-dwarf and subdwarf candidates that have a high probability of being genuine.Comment: Accepted ApJL version. 3 figures (2 in color). Table of candidate new WDs closer than 20 pc is now include

Improved Astrometry and Photometry for the Luyten Catalog. I. Bright Stars

We outline the construction of an updated version of the New Luyten Two-Tenths (NLTT) catalog of high proper motion stars, which will contain improved astrometry and photometry for the vast majority of the ~59,000 stars in NLTT. The bright end is constructed by matching NLTT stars to Hipparcos, Tycho-2, and Starnet; the faint end by matching to USNO-A and 2MASS. In this first paper, we detail the bright-end matching procedure. We show that for the majority of stars in his catalog, Luyten measured positions accurate to 1" even though he recorded his results much more coarsely. However, there is a long tail of position errors, with one error as large as 11 deg. Proper-motion errors for the stars with small position errors are 24 mas/yr (1 sigma) but deteriorate to 34 mas/yr for stars with inferior positions. NLTT is virtually 100% complete for V15 deg, but completeness in this magnitude range falls to about 75% at the Galactic plane. Incompleteness near the plane is not uniform, but is rather concentrated in the interval -80<l<20, where the Milky Way is brightest.Comment: Submitted to ApJ, 28 pages including 7 figure

Islam, Politics and Identity in West Sumatra

Since Indonesia has undergone a decentralisation phase, its regions have searched for their local identities. In West Sumatra, for instance, Islam is dominant. Con­se­quently, there has been a constant attempt to infuse Islamic values into social, political and economic aspects. The paper seeks to contextualise the key phases in the history of West Sumatra in the broader history of the archipelago and the Malay world, and to show how key events in West Sumatra and at the national level set the parameters for later debates about Islam and identity in the region. The paper argues that now, as in the past, the relationship between Islam, a global religion, and Minangkabau culture was, and is, simul­ta­neously contested. It is also found that Islam as an ideology was subordinated after Independence days, and again under the New Order. The strong association between Islam and regional identity only solidified in the post-Suharto. Now, regional governments has been utilising claims that local customs are based on Islam and Islam is based on the Qur'an

Aspek Keselamatan pada Aplikasi Reaktor Nuklir Suhu Tinggi untuk Proses Steam Reforming Gas Alam

ASPEK KESELAMATAN PADA APLIKASI REAKTOR NUKLIR SUHU TINGGI UNTUK PROSES STEAM REFORMING GAS ALAM. Telah dilakukan pengkajian aspek keselamatan pada aplikasi reaktor nuklir suhu tinggi untuk proses steam reforming gas alam. Aspek keselamatan dasar pada kopel reaktor nuklir dengan proses kimia adalah mencegah kemungkinan lepasnya bahan-bahan radioaktif ke lingkungan dan atau ke zona proses kimia. Pada kopel nuklir untuk proses kimia, digunakan penukar panas intermediate (IHX) sebagai interface yang memisahkan antara zona nuklir dengan zona proses kimia. IHX adalah penukar panas helium-helium, dimana helium primer (905oC) mampu memindahkan panasnya ke helium sekunder (890oC). Untuk menjaga agar tidak terjadi lepasan bahan-bahan radioaktif dari zona nuklir, diterapkan sistem keseimbangan tekanan, yaitu tekanan proses kimia (4,5 MPa) dirancang lebih besar dari tekanan helium sekunder (4,1 MPa) maupun helium primer (4,0 MPa). Rancangan ini mengakibatkan kondisi operasi panas proses yang mampu disediakan oleh reaktor nuklir menjadi tidak optimal yaitu hanya mencapai sekitar 800oC pada daerah tabung katalisator. Kondisi ini mengakibatkan efisiensi termal steam reforming gas alam dengan panas nuklir hanya mencapai 50%, jauh di bawah proses dengan sumber panas bahan bakar fosil (80-85%). Sejumlah modifikasi desain operasi, seperti memanfaatkan reformer tipe bayonet yang dilengkapi dengan orifice baffle, dan peningkatan efektivitas pemanfaatan panas, mampu meningkatkan efisiensi termal steam reforming gas alam dengan panas nuklir menjadi sekitar 78%

Transfer Learning for Thermal Comfort Prediction in Multiple Cities

HVAC (Heating, Ventilation and Air Conditioning) system is an important part of a building, which constitutes up to 40% of building energy usage. The main purpose of HVAC, maintaining appropriate thermal comfort, is crucial for the best utilisation of energy usage. Besides, thermal comfort is also crucial for well-being, health, and work productivity. Recently, data-driven thermal comfort models have got better performance than traditional knowledge-based methods (e.g. Predicted Mean Vote Model). An accurate thermal comfort model requires a large amount of self-reported thermal comfort data from indoor occupants which undoubtedly remains a challenge for researchers. In this research, we aim to tackle this data-shortage problem and boost the performance of thermal comfort prediction. We utilise sensor data from multiple cities in the same climate zone to learn thermal comfort patterns. We present a transfer learning based multilayer perceptron model from the same climate zone (TL-MLP-C*) for accurate thermal comfort prediction. Extensive experimental results on ASHRAE RP-884, the Scales Project and Medium US Office datasets show that the performance of the proposed TL-MLP-C* exceeds the state-of-the-art methods in accuracy, precision and F1-score

Quadrature noise in light propagating through a cold 87Rb atomic gas

We report on the study of the noise properties of laser light propagating through a cold 87Rb atomic sample held in a magneto-optical trap. The laser is tuned around the Fg = 2 \rightarrow Fe = 1, 2 D1 transitions of 87Rb. We observe quadrature-dependent noise in the light signal, an indication that it may be possible to produce squeezed states of light. We measure the minimum and maximum phase-dependent noise as a function of detuning and compare these results to theoretical predictions to explore the best conditions for light squeezing using cold atomic Rb