1,248 research outputs found

    The rise and fall of the compact jet in GRO J1655-40

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    In this work, we present some preliminary results on a multi-wavelength (radio/infrared/optical/X-ray) study of GRO J1655-40 during its 2005 outburst. We focus on the broadband spectral energy distribution during the different stages of the outburst. In particular, using this unprecedented coverage, and especially thanks to the new constraints given in the mid-IR by Spitzer, we can test the physical self-consistent disk-jet model during the hard state, where the source shows radio emission from a compact jet. The hard state broadband spectra of the observations during the decay of the outburst, are fairly well fit using the jet model with parameters overall similar to those found for Cyg X-1 and GX 339-4 in a previous work. However, we find that, compared to the other two BHs, GRO J1655-40 has a much higher jet power (at least a factor of 3), and that, most notably, the model seems to underestimate the radio emissio

    Analisis Penggantian Material Agregat Klas A Dan B Menjadi CTRB Paket Peningkatan Jalan Muara Teweh – Benangin Menggunakan Metode AASTHO’93

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    Roads are one of the infrastructures that will accelerate the growth and development of an area and open up socio-economic and cultural relations between regions. Along with the progress of infrastructure, the government has developed transportation facilities, namely the improvement of the Muara Teweh - Benangin road. In the Law of the Republic of Indonesia No.38 of 2004 concerning road infrastructure, roads have an important role in realizing the development of the nation's life. The improvement of the Muara Teweh - Benangin road used the flexible pavement thickness planning with the AASTHO 1993 method, the planned road life for flexible pavement was 20 years and the traffic growth factor was 6%. Sources of data used to plan flexible pavements were obtained from the Ministry of Public Works, Directorate General of Highways - National Executive Office VII. The data derived from the documentation is CBR data of subgrade and average traffic (LHR). These data are the basis most needed in planning a flexible pavement using the AASTHO method 1993. Based on the results of the calculation of the flexible pavement thickness planning using the AASTHO method, the following comparisons are obtained: (a) the total thickness of the surface layer HRS-Base / ATB 6 cm + HRS WC 3 cm, the upper foundation layer of class A = 15 cm, and the lower foundation layer of class B = 20 cm at a cost of Rp. 35,742,463,681, with an implementation time of 265 calendar days. (b) total surface layer thickness of HRS-Base / ATB 6 cm + HRS WC 3 cm, foundation layer CTRB 35 cm, at a cost of Rp. 34,278,182,220, - with execution time of 250 calendar days, resulting in a cost efficiency of Rp. 1,464,281,462, - with a difference of 15 calendar day

    Resistance, Agency and Violence: Dalit Women\u27s Education in Kerala, India

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    This dissertation is a critical feminist analysis of the discourses, narratives and hegemonic power structures that define Dalit women\u27s lives in Kerala, India. It focuses on intergenerational narratives of women and girls to illuminate how Dalit communities navigate development by specifically focusing on their educational narratives. To explore Dalit narratives, I conducted fieldwork in Kerala using in-depth interviews, photovoice, and participant observation as primary data. I coupled my primary data with secondary data sources such as development reports, trend data and newspapers to document how Dalit needs are framed. This research uses postcolonial feminist theory as it applies to the Kerala context along with intersectionality of identities as a conceptual framework to understand how gender, class, caste and religion shape Dalit women\u27s education across different generations.;The findings of this study speak to three specific themes: (1) the material and social locations held by women and girls in the Dalit communities, (2) the neoliberal forces shaping Kerala\u27s education, and (3) the patriarchal forces in the context of marriage and gender-based violence in Dalit homes, communities and schools. This research exposes the gendered subjectivities and vulnerabilities that Dalit women navigate through resistance, agency and power. Thus, by offering a contextualized place-based study of Dalit lives in Kerala, I argue that the discourses and practices of development in Kerala have failed to attend to Dalit needs

    Optimasi Daya Mesin dan Konsumsi Bahan Bakar Mesin Toyota Seri 5k melalui Penggunaan Pengapian Booster

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    Proses pembakaran adalah proses secara fisik yang terjadi di dalam silinder. Proses pembakaran dimulai pada saat busi memercikkan bunga api hingga terjadi proses pembakaran. Dalam penelitian ini digunakan metode eksperimen yaitu membandingkan daya dan konsumsi bahan bakar antara pengapian standar dengan pengapian menggunakan booster. Berdasarkan data hasil uji coba perbandingan antara sistem pengapian standar dengan pengapian yang menggunakan booster dengan objek penelitian mesin Toyota seri 5K diketahui adanya kenaikan 2.61% daya menjadi 27.723 kW dari 27.17 kW antara sistem pengapian standar dengan pengapian yang menggunakan booster pada putaran mesin 2400 rpm. Sedangkan prosentase kenaikan rerata daya sebesar 2.79 %. Penggunaan booster juga membuat penggunaan konsumsi bahan bakar spesifik (sfc) antara sistem pengapian standar dengan pengapian yang menggunakan booster. Prosentase penurunan rerata konsumsi bahan bakar spesifik (sfc) sebesar 6.99%. Pada sistem pengapian yang menggunakan booster, sfc minimum sebesar 0.219 kg/kWh pada putaran mesin 2200 rpm. Pada pengapian standar sfc minimum sebesar 0.231 kg/kWh pada putaran mesin 2400 rpm

    Galactic black holes in the hard state, a multiwavelength view of accretion and ejection

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    The canonical hard state is associated with emission from all three fundamental accretion components: the accretion disk, the hot accretion disk corona and the jet. On top of these, the hard state also hosts very rich temporal variability properties (low frequency QPOs in the PDS, time lags, long time scale evolution). Our group has been working on the major questions of the hard state both observationally (with multi-wavelength campaigns using RXTE, SWIFT, SUZAKU, SPITZER, VLA, ATCA, SMARTS) and theoretically (through jet models that can fit entire SEDs). Through spectral and temporal analysis we seek to determine the geometry of accretion components, and relate the geometry to the formation and emission from a jet. In this presentation I will review the recent contributions of our group to the field, including the SWIFT results on the disk geometry at low accretion rates, the jet model fits to the hard state SEDs (including SPITZER data) of GRO J 1655-40, and the final results on the evolution of spectral (including X-ray, radio and infrared) and temporal properties of selected black holes in the hard states. I will also talk about impact of ASTROSAT to the science objectives of our group

    Kondo effect in CeXc_{c} (Xc_{c}=S, Se, Te) studied by electrical resistivity under high pressure

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    We have measured the electrical resistivity of cerium monochalcogenices, CeS, CeSe, and CeTe, under high pressures up to 8 GPa. Pressure dependences of the antiferromagnetic ordering temperature TNT_{N}, crystal field splitting, and the lnT\ln T anomaly of the Kondo effect have been studied to cover the whole region from the magnetic ordering regime at low pressure to the Fermi liquid regime at high pressure. TNT_{N} initially increases with increasing pressure, and starts to decrease at high pressure as expected from the Doniach's diagram. Simultaneously, the lnT\ln T behavior in the resistivity is enhanced, indicating the enhancement of the Kondo effect by pressure. It is also characteristic in CeXc_{c} that the crystal field splitting rapidly decreases at a common rate of 12.2-12.2 K/GPa. This leads to the increase in the degeneracy of the ff state and further enhancement of the Kondo effect. It is shown that the pressure dependent degeneracy of the ff state is a key factor to understand the pressure dependence of TNT_{N}, Kondo effect, magnetoresistance, and the peak structure in the temperature dependence of resistivity.Comment: 9 pages, 5 figures, accepted for publication in J. Phys. Soc. Jp

    Infrared interferometry to spatially and spectrally resolve jets in X-ray binaries

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    Infrared interferometry is a new frontier for precision ground based observing, with new instrumentation achieving milliarcsecond (mas) spatial resolutions for faint sources, along with astrometry on the order of 10 microarcseconds. This technique has already led to breakthroughs in the observations of the supermassive black hole at the Galactic centre and its orbiting stars, AGN, and exo-planets, and can be employed for studying X-ray binaries (XRBs), microquasars in particular. Beyond constraining the orbital parameters of the system using the centroid wobble and spatially resolving jet discrete ejections on mas scales, we also propose a novel method to discern between the various components contributing to the infrared bands: accretion disk, jets and companion star. We demonstrate that the GRAVITY instrument on the Very Large Telescope Interferometer (VLTI) should be able to detect a centroid shift in a number of sources, opening a new avenue of exploration for the myriad of transients expected to be discovered in the coming decade of radio all-sky surveys. We also present the first proof-of-concept GRAVITY observation of a low-mass X-ray binary transient, MAXI J1820+070, to search for extended jets on mas scales. We place the tightest constraints yet via direct imaging on the size of the infrared emitting region of the compact jet in a hard state XRB.Comment: 12 Pages, 3 figures, accepted for publication in MNRA
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