1,722,303 research outputs found

    Characterization and source separation of turbofan broadband noise using intra-stage measurements

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    The broadband (BB) noise generated in the fan stage is a significant contributor to the total engine noise with the dominant noise generation mechanisms attributed to the self-noise at the trailing edges (TE) of the fan blades and the rotor-stator interaction noise at the leading edges (LE) of the outlet guide vanes (OGV). Despite more than 50 years of research, the fan BB noise is not properly understood, and its rotor (fan) and stator (OGV) components haven’t been properly quantified. The noise measurements in the engine intra-stage between the fan TE and OGV LE permit a direct comparison between the BB noise characteristics and the relative levels generated by the fan and OGV, unlike the engine intake and bypass sections, wherein the noise from the fan and OGV arrive simultaneously in one direction and suffer some degree of acoustic blockagedue to one another. In this thesis, we exclusively focus on the noise measurements made in the intra-stage region to identify and reveal the fundamental characteristics of the fan BB noise and develop suitable phased array techniques to overcome the measurement challenges and accomplish the desired source separation.In our present work, we propose a theoretical point source model for the engine intra-stage with empirically determined source parameters, which effectively reproduces the measured relative BB modal pressure distribution characteristics due to the fan and OGV. The consistency of these source parameters is demonstrated across different turbofan rigs and operating conditions to bring out their universality. The problem of acoustic mode detection and wave splitting in the engine intra-stage are systematically investigated with suitable phased array methods developed and implemented, which reveal the OGV to dominate the fan noise spectrum by more than 6 dB at both approach and cutback. The concept of modal axial group velocity is investigated for ducted swirling flows, based on which modal sound power distributions have been estimated for measured intra-stage noise data at approach and cutback, which show conformity as well as deviation from the ideal equal-power-per-mode concept

    sj-docx-1-rop-10.1177_0734371X211062481 – Supplemental material for Explaining High Performance Among Indian Administrative Service (IAS) Officers: A Job Demands-Resources Perspective

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    Supplemental material, sj-docx-1-rop-10.1177_0734371X211062481 for Explaining High Performance Among Indian Administrative Service (IAS) Officers: A Job Demands-Resources Perspective by Surya Prakash Pati and Ram Kumar Kakani in Review of Public Personnel Administration</p

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    ram kumar

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    ram kumar

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    Theme‑Based Book Review: Shifting Views of Public Sector Corruption

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    This theme-based book review considers three recent titles related to public sector corruption: Populism and corruption: The other side of the coin, edited by Jonathan Mendilow and Eric Phelippeau; Critical perspectives on public systems management in India, by Amar KJR Nayak and Ram Kumar Kakani; and Handbook on corruption, ethics and integrity in public administration, edited by Adam Graycar.Journal ArticleFinal article publishe
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