Temperature profile of an elliptic bore journal bearing

Non-circularity in bearing bore is obvious due to manufacturing irregularities like eccentricity in tool and job axis, small-amplitude vibration during machining, etc. But design relations/charts in journal bearing are based on bore circularity concept. Hence in reality non-circularity in bearing bore is bound to occur. The non-circularity in this paper is assumed to be elliptical and the numerical solution of Reynolds equation and Energy equation has been carried out for an elliptic bore journal bearing to outline the temperature profile. A comparison is made with the circular case to analyse the effect of this irregularity. The energy equation is solved adiabatically.     

Synthesis of nanocrystalline 8 mol% yttria stabilized zirconia powder from sucrose derived organic precursors

An organic precursor synthesis of 8 mol% yttria stabilized zirconia (YSZ) powder from Zr–Y composite nitrate solution and sucrose has been studied. Oxidation of sucrose in Zr–Y composite nitrate solution containing excess nitric acid in situ generates hydroxy carboxylic acids that forms a white sol which showed peaks at 1640 cm⁻¹ and 1363 cm⁻¹ in IR spectrum corresponding to hydroxy carboxylic acid complexes of Zr and Y. Precursor mass obtained by drying the sol on calcinations at 600 °C produced loosely agglomerated particles of cubic YSZ. Deagglomerated YSZ contain submicron particles with D₅₀ value of 0.5 μm and the particles are aggregates of nanocrystallites of nearly 10 nm size. Compacts prepared by pressing the YSZ powder sintered to 96.7% TD at 1450 °C. The sintered YSZ ceramic showed an average grain size of 2.2 μm.     

Removal of Water from Spent Phosphoric Acid Using a Sandwich Silicon Carbide Ceramic Membrane

It is important to develop an energy- and cost-efficient method of concentrating phosphoric acid because it is widely used in several industries. Three different ceramic membranes, namely, a silicon carbide (SiC) membrane, a TiO₂-coated SiC membrane, and a sandwich membrane of TiO₂ between SiC, were successfully applied for the selective separation of water from spent phosphoric acid. SiC was selected as raw material, TiO₂ as supporting material. The membrane was characterized by various instruments to check all parameters. Using the solution diffusion, statistical modeling of these membranes was performed and the membrane parameters, such as membrane diffusivity and mass transfer coefficient, were calculated. By reducing the porosity of the membrane, the desired separation can be improved.     

Optic disc analysis in retinal fundus using L2 norm of contourlet subbands,superimposed edges,and morphological filling

Optic disc (OD) analysis is an important stage in detecting retinal diseases and existing approaches are not suitable for analyzing multiple examinations in a single process. This paper proposes a new unified method to detect (i) OD center, (ii) OD boundary, and (iii) enhancement of vasculature within the OD region in a single algorithm. This paper presents a unique strategy, which involves L² norm of contourlet subbands of retinal images to locate the OD center. A novel OD boundary tracing approach that integrates morphological operations, and segmentation region growing techniques, with the aid of the OD center as a seed point, is presented. Among the two novel OD vasculature enhancement techniques, one of which involves image sharpening to improve the local contrast followed by histogram equalization to increase the overall contrast of the fundus image. Edge superimposing with the flood fill technique is another approach used for vasculature enhancement. The algorithm is tested on DRIVE (40), STARE (81), MESSIDOR (1200), E-ophtha (87), Diaretdb1 (89) images, out of which 40, 77, 1182, 87, and 87 images are detected correctly. The Figure of Merit (FOM) is used to confirm the correctness of the boundary tracking performance (97.15%). EME, SSIM, and other parameters are used to assess the efficiency of the vasculature enhancement technique.

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Modeling the viral load dependence of residence times of virus-laden droplets from COVID-19-infected subjects in indoor environments

In the ongoing COVID-19 pandemic situation, exposure assessment and control strategies for aerosol transmission path are feebly understood. A recent study pointed out that Poissonian fluctuations in viral loading of airborne droplets significantly modifies the size spectrum of the virus-laden droplets (termed as “virusol”) (Anand and Mayya, 2020). Herein we develop the theory of residence time of the virusols, as contrasted with complete droplet system in indoor air using a comprehensive “Falling-to-Mixing-Plate-out” model that considers all the important processes namely, indoor dispersion of the emitted puff, droplet evaporation, gravitational settling, and plate out mechanisms at indoor surfaces. This model fills the existing gap between Wells falling drop model (Wells, 1934) and the stirred chamber models (Lai and Nazarofff, 2000). The analytical solutions are obtained for both 1-D and 3-D problems for non-evaporating falling droplets, used mainly for benchmarking the numerical formulation. The effect of various parameters is examined in detail. Significantly, the mean residence time of virusols is found to increase nonlinearly with the viral load in the ejecta, ranging from about 100 to 150 s at low viral loads (<10⁴/ml) to about 1100–1250 s at high viral loads (>10¹¹/ml). The implications are discussed.     

Dynamic ranking-based MapReduce job scheduler to exploit heterogeneous performance in a virtualized environment

The Journal of Supercomputing - “More data, more information.” Big data helps businesses and research communities to gain insights and increase productivity. Many public cloud service...     

Mangiferin nanoparticles fortified dairy beverage as a low glycemic food product: its quality attributes and antioxidant properties

Mangiferin-encapsulated β-lactoglobulin–chitosan (mangiferin/βLG-CS) nanoparticles were fortified in milk to obtain a low glycemic index (GI) food product with high antioxidant capacity. The present study evaluated the bioaccessibility and bioavailability of mangiferin in milk fortified with nanoparticles. Fortification reduced the GI of milk by 34.5%. A mathematical model was developed to evaluate the lactose digestion, in terms of reducing sugar formed in milk by determining the digestion rate (k), and a significant reduction in k was observed. The bioaccessibility of mangiferin was enhanced by fortification. Fortified milk showed good antioxidant, lipid peroxidation inhibition and protein oxidation inhibition properties. Mangiferin nanoparticles fortified dairy beverage as an ideal food product with high antioxidant capacity and can inhibit lipid peroxidation and protein oxidation. It may be used as a low GI food product.     

Inference of COVID-19 epidemiological distributions from Brazilian hospital data

Knowing COVID-19 epidemiological distributions, such as the time from patient admission to death, is directly relevant to effective primary and secondary care planning, and moreover, the mathematical modelling of the pandemic generally. We determine epidemiological distributions for patients hospitalized with COVID-19 using a large dataset (N = 21 000 − 157 000) from the Brazilian Sistema de Informação de Vigilância Epidemiológica da Gripe database. A joint Bayesian subnational model with partial pooling is used to simultaneously describe the 26 states and one federal district of Brazil, and shows significant variation in the mean of the symptom-onset-to-death time, with ranges between 11.2 and 17.8 days across the different states, and a mean of 15.2 days for Brazil. We find strong evidence in favour of specific probability density function choices: for example, the gamma distribution gives the best fit for onset-to-death and the generalized lognormal for onset-to-hospital-admission. Our results show that epidemiological distributions have considerable geographical variation, and provide the first estimates of these distributions in a low and middle-income setting. At the subnational level, variation in COVID-19 outcome timings are found to be correlated with poverty, deprivation and segregation levels, and weaker correlation is observed for mean age, wealth and urbanicity.     

Putting personality in context: determinants of research productivity and impact in political science

Scientometrics - Research on the determinants of scholarly productivity is flourishing, driven both by long-standing curiosity about its wide variation, and by recent concern over race and gender...