Upper Limits on the Pulsed Radio Emission from the Geminga Pulsar at 35 & 327 MHz

We report here our observations at 35 MHz and 327 MHz made in the direction of the Gamma Ray pulsar Geminga. Based on the observed absence of any significant pulsed emission from this source above our detection thresholds at the two frequencies, we obtain useful upper-limits for the average flux to be 75-100 mJy at 35 MHz, and 0.2-0.3 mJy at 327 MHz. We discuss a few possible reasons for the ``radio-quiet'' nature of this pulsar at frequencies other than around 100 MHz.Comment: Accepted for publication in Astronomy & Astrophysic

Kinerja Penerangan Alam pada Hunian Rumah Susun Dupak Bangunrejo Surabaya

Residential buildings require adequate natural light distribution for visual comfort and daily productivity. To analyze natural light distribution is to use illuminance dan daylight factor (DF) values, in relation to the atmospheric condition and wet tropical environment. Problems arise from the dimensions, materials, opening orientations, overhangs and obstructions used in low-cost residential flats. This research aims to observe the influence of the dimensions in openings, overhangs and obstructions on the lighting strategy and the role of the three aspects in increasing visual comfort. The simulation activity of this natural lighting phenomenon is performed using the SUPERLITE v. 2.0. program. The results show that dimensions, materials and the orientation of the openings influences the contour pattern of lighting in the building and triggers glare if the lighting contrast is too high. Overhangs over the openings that are too large may decrease light penetration inside the building because they hinder Sky Component (SC), but are likely to increase Externally Reflected Component (ERC) value depending on the reflection potential of the surface. The presence of obstuction infront of an opening can decrease light intensity inside the building because of the decrease in SC value but can also minimize glare since the light intensity entering the building would be more even in distribution

Kinerja Ventilasi pada Hunian Rumah Susun Dupak Bangunrejo Surabaya

Natural ventilation for dwellings in tropical wet regions is very important for health. The requirement for natural ventilation is measured in air change rate (ACH) constituting of the availability of fresh air, quality of air circulation, heat losses, and unwanted gasses in the room. Wind speed is useful for accelerating evaporative cooling process and thus plays an important role for thermal comfort in the interior room. Local wind conditions affects the ventilation of a building and therefore might cause problems in predicting the natural ventilation and thermal comfort in a high-rise building, especially in the area and orientation of an opening that is not perpendicular to the wind direction. Ventilation parameters that are to be observed are the air flow rate and air change (ACH) that are gained from a simulation using the AILOS software. The results show that if the opening orientation is at the wind shadow zone, the interior space will not receive wind, it obtains sucking pressure instead. The design of an opening should focus on the area of inlet and outlet because when ACH does not increase, consequently internal wind speed becomes low and thermal comfort will not be met

Pengaruh Elemen Interior Terhadap Karakter Akustik Auditorium

Auditorium is a place to perform theatre, opera and music. Kinds of show that can be enjoyed comfortably or otherwise depend on the quality of room acoustic. Interior designers also contribute in successful or unsuccessful of a performance, which is in creating acoustic character quality. When designing auditorium interior, a designer should consider sound esthetic elements of acoustic. The best acoustic criteria in an auditorium are influenced by shape of the room and space dimension, where both can create acoustic parameter either objectively or subjectively. The arrangement and the finishing materials of the audience seats, opening view, shape and finishing of the surfaces (reflective or absorptive) that covered the auditorium are important elements which need attention

Pertimbangan Aspek Kejiwaan terhadap Feng Shui dalam Perancangan Interior

The truth of applying feng shui in interior design is always doubted because feng shui is still consider mystically, unlogic, and unusual, therefore it needs facts of this potential feng shui. As knowledge, feng shui psychologically plays important role for home design that it increases psychological life of the residents

Optimasi Sistem Pencahayaan Buatan pada Ruang Labo¬rato¬rium Kampus

Salah satu penunjang kegiatan akademik dalam proses belajar mengajar di kampus adalah ruang laboratorium. Kegiatan di dalam ruang laboratorium dapat berjalan dengan efektif jika didukung dengan sistem pencahayaan buatan yang memadai. Tidak jarang sistem pencahayaan buatan dalam sebuah kampus kurang mendapat perhatian karena pada saat perancangan nilai ekonomis yang menjadi perhatian utama. Pada laboratorium Jurusan Sastra Inggris dan Jurusan Ilmu Komunikasi di Universitas Kristen Petra Surabaya hanya terdapat 1 dari 9 laboratorium yang memenuhi standar tingkat luminasi buatan. Dengan bantuan program software DIALux 4.9 dilakukan proses optimasi sistem pencahayaan buatan pada beberapa laboratorium yang belum memenuhi persyaratan tersebut. Hasil optimasi menunjukkan bahwa untuk memperoleh sistem pencahayaan buatan yang efektif dan efisien perlu dilakukan penggantian beberapa tipe lampu dan warna dinding ruang laboratoriu

Search for coronal temperature variation in Seyfert galaxies

While the temperature of the X-ray corona ($\rm{kT_e}$) in active galactic nuclei (AGN) are known for many sources, its variation, if any, is limited to a handful of objects. This is in part due to the requirement of good signal-to-noise X-ray spectra covering a wide range of energies. We present here results on the X-ray spectral analysis of 18 Seyferts, having more than one epoch of observations to look for variation in $\rm{kT_e}$. The data for a total of 52 epochs on these 18 AGN were taken from observations carried out by NuSTAR in the 3$-$79 keV energy band. From phenomenological and physical model fits to the multi-epoch data on these 18 sources from {\it NuSTAR}, we could constrain the cut-off energy ($E_{cut}$) in a large fraction of the sources. Also, from Comptonized model fits, we could obtain $\rm{kT_e}$ for our sample. Of the 18 sources, at the 90 per cent confidence level, evidence for variation in $\rm{kT_e}$ was found for only one source, namely MCG+08-11-011. For this source, between two epochs, separated by about five years, we found $\rm{kT_e}$ to decrease from 57$^{+29}_{-16}$ keV to 30$^{+11}_{-7}$ keV. During the same period, the flux decreased from (12.60 to 14.02) $\times$ 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$ and the optical depth increased from 1.68 to 2.73. We thus found a positive correlation between flux and coronal temperature with a reduction of about 40 per cent in optical depth. Our observations tend to favour the vertically outflowing corona scenario for the observed variation in $\rm{kT_e}$ in MCG+08-11-011.Comment: 17 pages, 7 figuers, accepted for publication in MNRAS-M