263,807 research outputs found
On the structure and origin of pressure fluctuations in wall turbulence: predictions based on the resolvent analysis
No full textWe generate predictions for the fluctuating pressure field in turbulent pipe flow by re-formulating the resolvent analysis of McKeon & Sharma (2010) in terms of the so-called primitive variables. Under this analysis, the nonlinear convective terms in the Fourier-transformed Navier-Stokes equations are treated as a forcing that is mapped to a velocity and pressure response by the resolvent of the linearized Navier-Stokes operator. At each wavenumber-frequency combination, the turbulent velocity and pressure field are represented by the most-amplified (rank-1) response modes, identified via a singular value decomposition of the resolvent. We show that these rank-1 response modes reconcile many of the key relationships between the velocity field, coherent structure (i.e., hairpin vortices), and the high-amplitude wall-pressure events observed in previous experiment and DNS. A Green’s function representation shows that the pressure fields obtained under this analysis correspond primarily to the fast pressure contribution arising from the linear interaction between the mean shear and the turbulent wall-normal velocity. Recovering the slow pressure requires an explicit treatment of the nonlinear interactions between the Fourier response modes. By considering the velocity and pressure fields associated with the triadically-consistent mode combination studied by Sharma & McKeon (2013), we identify the possibility of an apparent amplitude modulation effect in the pressure field, similar to that observed for the streamwise velocity field. However, unlike the streamwise velocity, for which the large scales of the flow are in phase with the envelope of the small-scale activity close to the wall, we expect there to be a ?/2 phase difference between the large scale wall-pressure and the envelope of the small-scale activity. Finally, we generate spectral predictions based on a rank-1 model assuming broadband forcing across all wavenumber-frequency combinations. Despite the significant simplifying assumptions, this approach reproduces trends observed in previous DNS for the wavenumber spectra of velocity and pressure, and for the scale-dependence of wall-pressure propagation speed
Dataset for Modular transmission line probes for microfluidic nuclear magnetic resonance spectroscopy and imaging
No full textDataset supports: Sharma, M. & Utz, M. (2019). Modular transmission line probes for microfluidic nuclear magnetic resonance spectroscopy and imaging. Journal of Magnetic Resonance, 303, 75-81.</span
Opposition control within the resolvent analysis framework
No full textThis paper extends the resolvent analysis of McKeon & Sharma (2010) to consider flow control techniques that employ linear control laws, focusing on opposition control (Choi et al. 1994) as an example. Under this formulation, the velocity field for turbulent pipe flow is decomposed into a series of highly amplified (rank-1) response modes, identified from a gain analysis of the Fourier-transformed Navier-Stokes equations. These rank-1 velocity responses represent propagating structures of given streamwise/spanwise wavelength and temporal frequency, whose wall-normal footprint depends on the phase speed of the mode. Opposition control, introduced via the boundary condition on wall-normal velocity, affects the amplification characteristics (and wall-normal structure) of these response modes; a decrease in gain indicates mode suppression, which leads to a decrease in the drag contribution from that mode. With basic assumptions, this rank-1 model reproduces trends observed in previous DNS and LES, without requiring high-performance computing facilities. Further, a wavenumber-frequency breakdown of control explains the deterioration of opposition control performance with increasing sensor elevation and Reynolds number. It is shown that slower-moving modes localized near the wall (i.e. attached modes) are suppressed by opposition control. Faster-moving detached modes, which are more energetic at higher Reynolds number and more likely to be detected by sensors far from the wall, are further amplified. These faster-moving modes require a phase lag between sensor and actuator velocity for suppression. Thus, the effectiveness of opposition control is determined by a trade-off between the modes detected by the sensor. However, it may be possible to develop control strategies optimized for individual modes. A brief exploration of such mode-optimized control suggests the potential for significant performance improvement
Strategic content and process in family business
No full textStrategic management is different in family firms. In these organizations, a family exercises significant influence over the firm’s crucial decision making processes and choices (Chua, Chrisman & Sharma, 1999). The uniqueness of family business revolves around the important influence of family in terms of determining the firm’s vision and control mechanisms, and the creation of unique resources, capabilities and management action patterns (Chrisman, Steier & Chua, 2008; Chua, Chrisman & Sharma, 2009; Sharma, 2004). This family influence makes the family business unique as it creates patterns of goals, strategies and structures that are often formulated, designed, and implemented in ways that can be radically different from non-family firms. These differences may result in either positive or negative effects on organizational outcomes such as competitive advantage and financial performance (Miller & Le Breton-Miller, 2006), non-financial performance and the preservation of socioemotional wealth (Gomez-Mejia et al., 2007; Zellweger & Nason, 2008), environmental stewardship (Berrone et al., 2010; Sharma & Sharma, 2011), and diversification decisions (Gomez-Mejia, Makri & Larraza-Kintana, 2010; Miller, Le Breton-Miller, & Lester, 2010).
To better capture this uniqueness, this chapter reviews current research on strategy in family business contexts, illustrating the main strategic issues addressed by the existing literature, and potential future extensions. The chapter includes a discussion of the key features of strategy in family businesses, of the potential sources of competitive advantage and disadvantage, and of different aspects of the strategic development process, and it is informed by previous similar efforts at reviewing and conceptualizing the family business strategy literature (Chrisman, Chua & Sharma, 2005; De Massis, Sharma, Chua & Chrisman, 2012; Dyer & Sanchez, 1998; Sharma, 2004; Sharma, Chrisman & Chua, 1997). The chapter also includes an illustration of the potential of a set of previously unused frameworks in understanding strategy and a future research agenda.
The chapter is structured along six sections: 1) a description of the method that was followed to single out the sample of 77 family business strategy scientific works on which the chapter is grounded; 2) an overview of the key contents, theoretical approaches, methods and outcome variables in family business strategy research, as emerging from the representative sample of studies; 3) a description of the key features of family firms that make their strategic choices, processes and outcomes different; 4) an illustration of key strategic contents as emerging from the extensive literature review, with a focus on growth in and around the founder’s core business; 5) a focus on corporate and portfolio strategies of diversification; 6) a concluding section including directions for future research
On the theorem of N. Singh and K. M. Sharma
No full textA new short proof of the Theorem of N. Singh and K. M. Sharma (see [7]) is given
Paraleptomenes darugiriensis Girish Kumar, Carpenter & Sharma 2014
No full text128) Paraleptomenes darugiriensis Girish Kumar, Carpenter & Sharma, 2014 Paraleptomenes darugiriensis Girish Kumar, Carpenter & Sharma, 2014b: 133. Type data: Holotype female, NZC. Type locality: East Garo Hills, Darugiri, Meghalaya. Distribution. India: Arunachal Pradesh, Assam, Meghalaya, Sikkim, West Bengal. (Girish Kumar et al. 2014b).Published as part of Gawas, Sandesh M., Kumar, Girish, Pannure, Arati, Gupta, Ankita & Carpenter, James M., 2020, An annotated distributional checklist of Vespidae (Hymenoptera: Vespoidea) of India, pp. 1-87 in Zootaxa 4784 (1) on page 33, DOI: 10.11646/zootaxa.4784.1.1, http://zenodo.org/record/386231
Rhynchium haemorrhoidale subsp. andamanicum Girish Kumar & Sharma 2013
No full texta) Rhynchium haemorrhoidale andamanicum Girish Kumar & Sharma, 2013 Rhynchium haemorrhoidale andamanicum Girish Kumar & Sharma, 2013: 114. Type data: Holotype female, NZC. Type locality: Delanipur, Port Blair, South Andaman, Andaman & Nicobar Islands, India. Distribution. India: Andaman & Nicobar Islands. (Girish Kumar & Sharma 2013).Published as part of Gawas, Sandesh M., Kumar, Girish, Pannure, Arati, Gupta, Ankita & Carpenter, James M., 2020, An annotated distributional checklist of Vespidae (Hymenoptera: Vespoidea) of India, pp. 1-87 in Zootaxa 4784 (1) on page 39, DOI: 10.11646/zootaxa.4784.1.1, http://zenodo.org/record/386231
Pseudoaspidogaster betwai Agrawal & Sharma 1990
No full text<i>Pseudoaspidogaster betwai</i> Agrawal & Sharma, 1990 <p> <i>Tor</i> <i>tor</i> (Actinopterygii); freshwater; intestine; ORI; India (Asia) (Agrawal & Sharma 1990).</p> <p> Remark: Agrawal & Sharma (1990) established Paraspidogasterinae within Aspidogastridae to accommodate <i>P</i>. <i>betwai</i>. However, Rohde (2002) considered this taxon as synonym of <i>Aspidogaster</i> or <i>Cotylaspis</i>.</p>Published as part of <i>Alves, Philippe V., Vieira, Fabiano M., Santos, Cláudia P., Scholz, Tomáš & Luque, José L., 2015, A Checklist of the Aspidogastrea (Platyhelminthes: Trematoda) of the World, pp. 339-396 in Zootaxa 3918 (3)</i> on page 366, DOI: 10.11646/zootaxa.3918.3.2, <a href="http://zenodo.org/record/241203">http://zenodo.org/record/241203</a>
Asphondylia singanallurensis Vasanthakumar & Palanisamy & Peter & Sharma 2020, sp. nov.
No full text<i>Asphondylia singanallurensis</i> Vasanthakumar & Sharma, sp. nov. <p>(Figs 1–22)</p> <p> The diagnostic characters of the genus, <i>Asphondylia</i> are discussed in detail by Gagné <i>et al.</i> (2018).</p> <p> <b>Type material</b>. Holotype ♂ (Ent 10/205), Singanallur Lake, Coimbatore, Tamil Nadu, India (10.9877°N; 77.0238°E),collected as gall by DV on 26.ix.2017; Paratype: 4 ♂ (Ent 10/206), collected as gall on 22.ix.2018, 3♀ (Ent 10/207), 6 larvae, collected as gall on 23.ix.2018), 6 pupae (Collected as gall on 22.ix.2018 and 12.vii.2019); 7 pupal exuviae same data as holotype.</p>Published as part of <i>Vasanthakumar, Duraikannu, Palanisamy, Senthilkumar, Peter, Vinny R. & Sharma, Radheshyam M., 2020, A new species of Asphondylia (Diptera: Cecidomyiidae) causing leaf galls on jujube, Ziziphus jujuba Mill. (Rhamnaceae) in India, pp. 196-200 in Zootaxa 4758 (1)</i> on page 196, DOI: 10.11646/zootaxa.4758.1.11, <a href="http://zenodo.org/record/3730785">http://zenodo.org/record/3730785</a>
Paratylenchus prunii Sharma, Sharma & Khan 1986
No full text<i>Paratylenchus prunii</i> Sharma, Sharma & Khan, 1986 Esmaeili & Heydari 2017: <p> 10♀: L = 324 (290–343) µm; <i>a</i> = 21.8 (20.3–23.2); <i>b</i> = 3.1 (3.0–3.5); <i>c</i> = 12.8 (10.7–17.5); St = 26.1 (24.0– 28.0) µm; V = 81 (79–83)</p> <p> 2♂: L = 275, 290 µm; <i>a</i> = 19.3, 21.2; <i>c</i> = 12.6, 13.8; Spicules = 14, 15 µm</p> <p>Associated plant and locality: Grapevine from Kermanshah (Esmaeili & Heydari 2 0 17 [F])</p>Published as part of <i>Ghaderi, Reza, Karegar, Akbar, Miraeiz, Esmaeil & Hesar, Abbas Mokaram, 2019, An updated and annotated checklist of the Tylenchulidae (Nematoda: Criconematoidea) of Iran, pp. 205-229 in Zootaxa 4545 (2)</i> on page 213, DOI: 10.11646/zootaxa.4545.2.3, <a href="http://zenodo.org/record/2618787">http://zenodo.org/record/2618787</a>
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