3,311 research outputs found
Dynamic rheology of capsule suspension: the role of unsteady capsule dynamics and multiparticle interaction
No full textThree-dimensional numerical simulations using immersed-boundary methods are performed to study the rheology of capsule suspensions. Two well-known dynamics of the capsules are the tank-treading and tumbling motions. The motivation of the thesis is twofold: first, to study the micro-macro link between the individual cell dynamics and the rheology of the cell suspension under a dilute condition, and, second, to extend the analysis to a dense suspension in which the multi-body interaction also contributes to the suspension rheology. A recent theoretical study in the limit of small deformation, supported by experimental work, suggested that the effective viscosity of a vesicle suspension in dilute limit exhibits a singularity in the form of a viscosity minimum at the threshold of the transition between the tank-treading and the tumbling motion. In the first part of the thesis, we extend this study to the dilute suspension of capsules undergoing large deformation. The objective here is to relate the time- dependent rheology with the time-dependent capsule dynamics, and study the role of the tank-treading-to- tumbling transition. We find that the time-averaged rheology obtained for the non-spherical capsules undergoing the unsteady motion is qualitatively similar to that obtained for the spherical capsules undergoing the steady tank-treading motion, and that the tank-treading-to-tumbling transition has only a marginal effect. The time-averaged rheology exhibits a shear viscosity minimum when the capsules are in a swinging motion at high shear rates but not at low shear rates unlike that of a vesicle suspension which exhibits a shear viscosity minimum at the point of transition. In the second part, we extend our study to dense suspension of initially spherical capsules. We find that the shear viscosity minimum gradually diminishes with increasing capsule volume fraction. We explain this result by decomposing the particle shear stress into elastic and viscous components. The elastic component is observed to increase but the viscous component remains constant with respect to increasing volume fraction. It is also shown that the elastic contribution is shear-thinning, but the viscous contribution is shear-thickening. The deformation and orientation dynamics of the capsules in dense suspension are also presented. Non-trivial results for the normal stress differences and particle pressure are also analysed.Ph. D.Includes bibliographical referencesIncludes vitaby Ram Chandra Murthy Kallur
Dynamics and rheology of a dilute suspension of elastic capsules
No full textThree-dimensional numerical simulations using front-tracking method are considered to study the dynamics and rheology of a suspension of elastic capsules in linear shear flow over a broad range of viscosity contrast (ratio of internalto- external fluid viscosity), shear rate (or, capillary number), and aspect ratio. First, we focus on the coupling between the shape deformation and orientation dynamics of capsules, and show how this coupling influences the transition from the tank-treading to tumbling motion. At low capillary numbers, three distinct modes of motion are identified: a swinging or oscillatory (OS) mode at a low viscosity contrast in which the inclination angle θ(t) oscillates but always remains positive; a vacillating-breathing (VB) mode at a moderate viscosity contrast in which θ(t) periodically becomes positive and negative, but a full tumbling does not occur; and a pure tumbling mode (TU) at a higher viscosity contrast. At higher capillary numbers, three types of transient motions occur, in addition to the OS and TU modes, during which the capsule switches from one mode to the other as (i) VB to OS, (ii) TU to VB to OS, and (iii) TU to VB. It is shown that the coupling between the shape deformation and orientation is the strongest in the VB mode. The numerical results are compared with the theories of Keller and Skalak, and Skotheim and Secomb. Significant departures from the two theories are discussed and related to the strong coupling between the shape deformation, inclination, and transition dynamics. We then address the rheology of a dilute suspension of liquid-filled elastic capsules. We consider capsules of spherical resting shape for which only a steady tank-treading motion is observed. It is shown that the suspension exhibits a shear viscosity minimum at moderate values of the viscosity ratio, and high capillary numbers. The normal stress differences are shown to decrease with increasing capillary number at high viscosity ratios. Such non-trivial results can neither be predicted by the small-deformation theory, nor can be explained by the capsule geometry alone. Physical mechanisms underlying these novel results are studied by decomposing the particle stress tensor into a contribution due to the elastic stresses in the capsule membrane, and a contribution due to the viscosity differences between the internal and suspending fluids. It is shown that the elastic contribution is shear-thinning, but the viscous contribution is shear-thickening. The coupling between the capsule geometry, and the elastic and viscous contributions is analysed to explain the observed trends in the bulk rheology.M.S.Includes bibliographical referencesby Ram Chandra Murthy Kallur
The Forman Christian College Monthly
No full textNational NumberRaja Ram Kumria-Editorial. pp. 2-3; Chiranjiva Lall Aggarwal-Essay-Stray Thoughts on Indian Nationalism. pp. 4-5; Kartar Singh Malhotra-The Brotherhood of Man. pp. 6-7; Rup Lall Verma-Story-Khalsa. pp. 7-9; Raja Ram Kumria-The Man in White. pp. 9-10; Bhatty, M. S.-A Talk with M. Paul Richards. pp. 10-12; Essay-The Place of Women in Nation Building. pp. 12-15; Shourie, M. M.-The Spirit of Christ in Mahatama Gandhi. pp. 15-16; Yagesh Chandra Trikha-Article-The Poetry of Mrs Naidu . pp. 16-19; Krishan Lal Goswami-Poetry-My India. pp. 19-20; Babu Ram Saraf-My Hostel from the Watch Tower. pp. 21-22; Bhatty, M. S.-Alumni Re-union. pp. 23-25; Velte, F. M.-Poetry-The Joys of Winter. pp. 25-26; Cyril P. K. Fazal-Their Wit and Wisdom. pp. 26-27; Raja Ram Kumria-The Anand Society. pp. 27-28; Pte. Bhag Singh Lamba-The U. T. C. pp. 28-29; Yagesh Chandra Trikha-""Greater India"". pp. 29-3
RAM-PGK: Prediction of Lysine Phosphoglycerylation Based on Residue Adjacency Matrix
No full textBackground: Post-translational modification (PTM) is a biological process that is associated with the modification of proteome, which results in the alteration of normal cell biology and pathogenesis. There have been numerous PTM reports in recent years, out of which, lysine phosphoglycerylation has emerged as one of the recent developments. The traditional methods of identifying phosphoglycerylated residues, which are experimental procedures such as mass spectrometry, have shown to be time-consuming and cost-inefficient, despite the abundance of proteins being sequenced in this post-genomic era. Due to these drawbacks, computational techniques are being sought to establish an effective identification system of phosphoglycerylated lysine residues. The development of a predictor for phosphoglycerylation prediction is not a first, but it is necessary as the latest predictor falls short in adequately detecting phosphoglycerylated and non-phosphoglycerylated lysine residues. Results: In this work, we introduce a new predictor named RAM-PGK, which uses sequence-based information relating to amino acid residues to predict phosphoglycerylated and non-phosphoglycerylated sites. A benchmark dataset was employed for this purpose, which contained experimentally identified phosphoglycerylated and non-phosphoglycerylated lysine residues. From the dataset, we extracted the residue adjacency matrix pertaining to each lysine residue in the protein sequences and converted them into feature vectors, which is used to build the phosphoglycerylation predictor. Conclusion: RAM-PGK, which is based on sequential features and support vector machine classifiers, has shown a noteworthy improvement in terms of performance in comparison to some of the recent prediction methods. The performance metrics of the RAM-PGK predictor are: 0.5741 sensitivity, 0.6436 specificity, 0.0531 precision, 0.6414 accuracy, and 0.0824 Mathews correlation coefficient
J. Marshall. Annual Report of the Director-general of Archaeology in India, 1920-21. Hirananda Shastri. Annual progress Report of the Archaeological Department, Jammu and Kashmir State, 1917-19. Ram Chandra Kak. Annual Report of the Archaeological Department, Jammu and Kashmir State, 1919-21. A. M. Hocart. Archaeological Survey of Ceylon. Annual Report, 1921-22. Ram Chandra Kak. Antiquities of Bhimbar and Rajauri
No full textParmentier Henri. J. Marshall. Annual Report of the Director-general of Archaeology in India, 1920-21. Hirananda Shastri. Annual progress Report of the Archaeological Department, Jammu and Kashmir State, 1917-19. Ram Chandra Kak. Annual Report of the Archaeological Department, Jammu and Kashmir State, 1919-21. A. M. Hocart. Archaeological Survey of Ceylon. Annual Report, 1921-22. Ram Chandra Kak. Antiquities of Bhimbar and Rajauri. In: Bulletin de l'Ecole française d'Extrême-Orient. Tome 23, 1923. pp. 456-460
Scientometric portrait of Ram Gopal Rastogi
Get PDFPublication productivity of Indian scientist (R.G. Rastogi) has been documented.
Scientometric analysis of 312 papers by Ram Gopal Rastogi published during 1954 to 1992 in various domains: (a) Luni -solar activity and quiet -time E & F- region (57); (b) Equatorial electric field and low and mid latitude iof:osphere (78); (c) Ionospheric E- region irregularities (19); (dj Ionospheric F- region irregularities (32); and (e) Magnetic disturbance effects on the equatorial low and mid latitude ionosphere (23) were analysed. Interdomainery contents and of the number of papers: a+b were 36; b+c and b+d were 20 each; b+e were 16;. c+e were 5; a+e were 3; d+e were 2; and a+d had only one publication. Highest collaborations were with H. Chandra (61), M.R. Deshpande (42), and G. Sethia (19) out of his total 97 collaborators. His highest productivity was during 1978 with 28 papers followed by 19 papers during 1977. The core journals preferred by him for publishing papers were: Indian Journal of Radio & Space Physics, India, and Journal of Atomic & Terrestrial Physics, UK (59 each), followed by Proceedings of the Indian Academy of Sciences, India (34). Most prolific title keywords with their frequencies were: Ionosphere (92); Equatorial (61); F-region (53); Equatorial electrojet region (40), and Magnetic equator (30)
A star-forming galaxy at z= 5.78 in the Chandra Deep Field South
Get PDFWe report the discovery of a luminous z = 5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an ‘i-drop’ from the GOODS public survey imaging with the Hubble Space Telescope/Advanced Camera for Surveys (object 3 in the work of Stanway, Bunker & McMahon 2003). The large colour of (i′−z′)AB = 1.6 indicated a spectral break consistent with the Lyman α forest absorption shortward of Lyman α at z≈ 6. The galaxy is very compact (marginally resolved with ACS with a half-light radius of 0.08 arcsec, so rhl 5. Our spectroscopic redshift for this object confirms the validity of the i′-drop technique of Stanway et al. to select star-forming galaxies atz≈ 6
Simultaneous Prediction of Actual and Average Values of Study Variable Using Stein-rule Estimators
Get PDFThe simultaneous prediction of average and actual values of study variable in a linear regression model is considered in this paper. Generally, either of the ordinary least squares estimator or Stein-rule estimators are employed for the construction of predictors for the simultaneous prediction. A linear combination of ordinary least squares and Stein-rule predictors are utilized in this paper to construct an improved predictors. Their efficiency properties are derived using the small disturbance asymptotic theory and dominance conditions for the superiority of predictors over each other are analyzed
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