1,612 research outputs found
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No full textSP Sixit, RAK Aggarwal, PS Dangi, NK Verma, MK Vyas, J Rana, A Sharma, VB Kharadi, GP Sabapara and SB Deshpande (2013) Phenotypic characteristics, management, performance and genetic variability in Surti breed of goat. Indian Journal of Animal Sciences 83 (4) : 423 - 427.Not AvailableNot Availabl
Effects of confinement and Reynolds number variation on the flow field of swirling jets
No full textSwirling jets (SJs) are commonly used in the burners of gas turbines to enhance mixing or to stabilize the flames. In this manuscript, a three-component stereo particle image velocimetry (SPIV) was applied to examine the near exit region of an isothermal swirling jet inside an octagonal-shaped combustion chamber (CC) with a focus on the impact of confinement and Reynolds number (Re) changes on the swirling flow field. Measurements were performed on an axial plus tangential entry swirl burner (ATSB) with a geometric swirl number (Sg) of 1.8 and two different Re, corresponding to 10900 and 21800. The results observed in our experimental work are scaled appropriately with the swirl number based on the flux of the axial momentum. The contours of mean axial velocity field reveal the occurrence of vortex breakdown (VB) for the confined jets compared to the unconfined jets for both Re's. Upon confinement, the flow field is dominated by the existence of VB with a wider inner recirculation zone (IRZ) and with enhanced axial velocity fluctuations. The enhancement in the Re further increased the IRZ and enhanced the magnitudes of the mean axial velocity and its fluctuations. The outcome obtained from these results includes a better knowledge of the swirl jet in the swirl burner's near region
Effects of Confinement and Reynolds Number Variation on the Flow Field of Swirling Jets
No full textSwirling jets are commonly used in the burners of gas turbines to enhance mixing or to stabilize the flames. In this manuscript, a stereo (3C2D) particle image velocimetry (SPIV) was applied to examine the near exit region of an isothermal swirling jet inside an octagonal-shaped combustion chamber with a focus on the effects of confinement and Reynolds number (Re) variation on the swirling flow field. Measurements were performed on an axial plus tangential entry swirl burner with a geometric swirl number (Sg) of 1.8 and two different Re, corresponding to 10,900 and 21,800. The results observed in our experimental work are scaled appropriately with the swirl number based on the flux of the axial momentum. The contours of the mean axial velocity field reveal the occurrence of vortex breakdown (VB) for the confined jets compared to the unconfined jets for both Reynolds numbers. Upon confinement, the flow field is dominated by the existence of VB with a wider central recirculation zone (CRZ) and with enhanced axial velocity fluctuations. The enhancement in the Re further increased the CRZ and enhanced the magnitudes of the mean axial velocity and its fluctuations. The outcome obtained from these results includes a better knowledge of the swirl jet in the swirl burner's near region. In addition, the experimental data can be useful for validating computational fluid dynamics (CFD) modeling
Investigation of the reactivity of AlCl3 and CoCl2 toward molten alkali-metal nitrates in order to synthesize CoAl2O4
No full textCobalt aluminate CoAl2O4 powder, constituted of nano-sized crystallites, is prepared, involving the reactivity of AlCl3 and CoCl2 with molten alkali-metal nitrates. The reaction at 450 °C for 2 h leads to a mixture of spinel oxide Co3O4 and amorphous γ-Al2O3. It is transformed into the spinel oxide CoAl2O4 by heating at 1000 °C. The powders are mainly characterized by XRD, FTIR, ICP, electron microscopy and diffraction, X-EDS and diffuse reflection. Their properties are compared to those of powders obtained by solid state reactions of a mechanical mixture of chlorides or oxides submitted to the same thermal treatment
Soft error hardening enhancement analysis of NBTI tolerant Schmitt trigger circuit
No full textBias temperature instability (BTI) and soft errors are major reliability concerns for deep submicron technologies. Negative BTI leads to an increase of the threshold voltage of PMOS transistors and is thus considered a serious challenge for improving circuit performance. In this paper, we concentrate on a design-time solution, i.e., more reliable NMOS only Schmitt Trigger with Voltage Booster (NST-VB). For this we analyzed the impact of BTI on the soft-error susceptibility of different CMOS circuits using HSPICE and performed critical charge simulations considering different supply voltages and stress time. From our results, we conclude that the NST-VB circuit has a higher critical charge when compared to CMOS inverters and Schmitt trigger (ST) based counterparts. NST-VB has improved the sensitivity of 62.48% and 55.10%, as compared to CMOS inverter and ST circuits, respectively, after three years of operation. To better assess soft error resilience, we introduce a soft error rate ratio (SERR) as a performance metric. Our analysis indicates that NST-VB has 12.62%, and 12.39% less SERR compared to ST and CMOS inverters. The effect of process variation on CMOS inverter, ST inverter and NST-VB circuit are analyzed using 5000 Monte Carlo simulations for critical voltages and we observe that the deviation of NST-VB is 6.06× and 6.89× less as compared to the CMOS and ST based inverters, respectively
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High-resolution Near-infrared Spectroscopy of a Flare around the Ultracool Dwarf vB 10
No full textWe present high-resolution observations of a flaring event in the M8 dwarf vB 10 using the near-infrared Habitable-zone Planet Finder (HPF) spectrograph on the Hobby-Eberly Telescope. The high stability of HPF enables us to accurately subtract a vB 10 quiescent spectrum from the flare spectrum to isolate the flare contributions and study the changes in the relative energy of the Ca ii infrared triplet, several Paschen lines, the He λ10830 triplet lines, and to select iron and magnesium lines in HPF's bandpass. Our analysis reveals the presence of a red asymmetry in the He λ10830 triplet, which is similar to signatures of coronal rain in the Sun. Photometry of the flare derived from an acquisition camera before spectroscopic observations and the ability to extract spectra from up-the-ramp observations with the HPF infrared detector enable us to perform time-series analysis of part of the flare and provide coarse constraints on the energy and frequency of such flares. We compare this flare with historical observations of flares around vB 10 and other ultracool M dwarfs and attempt to place limits on flare-induced atmospheric mass loss for hypothetical planets around vB 10. © 2022. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
On the Extended Forms of Phenomenological Models for the Lattice Dynamics of BCC Transition Metals
No full textThe Sharma-Joshi and Krebs phenomenological models for the lattice dynamics of cubic metals have been extended and are applied to study the phonon dispersion curves of tungsten, a metal for whlch long range forces are also important. It has been found that, unlike extended forms of the de Launay model (Shukla and Cavalheiro 1973a) for certain cubic metals, the models studied here for b.c.c. transition metals are not always adequate. Possible reasons for the shortcomings of the results are pointed out and discussed. The role of angular forces, particularly when they are used along with a fairly good conduction electron-ion interaction term, has been examined and found to be unimportant</jats:p
Benign Mucous Membrane Pemphigoid: A Case Report
No full textBenign Mucous Membrane Pemphigoid (MMP) is a vesiculobullous (VB) lesion that affects oral and nasal mucosa, oropharynx, conjunctiva, and genital mucosa. It is considered an autoimmune disease. Autoantibodies are produced due to several external factors or genetic factors. It creates many complications, such as defects in vision, voice alteration (hoarseness), airway obstruction, and dyspareunia. The subepithelial blisters form due to these antibodies. Treatment modalities differ from topical steroids to systemic steroid therapy based on the nature and severity of clinical symptoms
Developments in non-mandatory disclosures in annual reports of companies: A case study
No full textThe paper investigates the extent of non-mandatory disclosure of information (NMD) in the annual reports of the 17 companies listed on the South Pacific Stock Exchange (SPSE) in Fiji, a developing country, and whether NMD by these companies has changed over time providing additional and useful information to stakeholders. The empirical data was gathered from the years 2008 to 2010 to provide a clear picture of the change in the level and extent of NMD, and its influences over the periods 2008 to 2010. It can be seen from the Fiji perspective that the mandatory requirements tend to have a financial focus. However, it would be expected that the level of company disclosures would have changed over time, with not only global market forces but through differing societal values which have increased the frequency and demand of non-mandatory reporting by companies. All companies showed some degree of NMD, and on average this demonstrates an increasing trend. The stakeholders are receiving more information about a company’s activities. The companies were analysed in light of recent developments in corporate governance by the Capital Markets Development Authority (CMDA) implementing their 10 corporate governance principles. This became a major driver of the increase in NMD levels of the disclosures in the annual reports of the listed companies. However, a large variation still exists between the level and extent of the NMD and the different listed companies. The minimum disclosure level found over the three years was 9.09 percent, which has increased to a minimum of 13.66 percent in 2010, and the maximum disclosure level over the three years was 81.82 percent. The findings for the extent of NMD was also similar where the minimum words used in NMDs was 114, increasing to 854 in 2010, and the maximum disclosure extent over the three years was 21,414 words. However, it was found that the measurement of counting words tended to fluctuate over different periods where significant events took place that affected the company. Therefore, it was established that disclosure is impacted by what happens in the reporting period, and can explain why one period may have greater disclosure than another. The paper aims to extend earlier work of Sharma & Davey (2013) on the extent of NMD in Fijian context. While Sharma & Davey (2013) considered voluntary disclosure from 1999-2005, our study reviews NMD over 2008-2010. The study has shown that corporate governance code issued in 2009 by Capital Market Development Authority has influenced the level of NMD
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