1,334 research outputs found

    Unified phase diagram of reversible-irreversible, jamming and yielding transitions in cyclically sheared soft sphere packings

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    Self-organization, and transitions from reversible to irreversible behaviour, of interacting particle assemblies driven by externally imposed stresses or deformation is of interest in comprehending diverse phenomena in soft matter. They have been investigated in a wide range of systems, such as colloidal suspensions, glasses, and granular matter. In different density and driving regimes, such behaviour is related to yielding of amorphous solids, jamming, and memory formation, \emph{etc.} How these phenomena are related to each other has not, however, been much studied. In order to obtain a unified view of the different regimes of behaviour, and transitions between them, we investigate computationally the response of soft sphere assemblies to athermal cyclic shear deformation over a wide range of densities and amplitudes of shear deformation. Cyclic shear deformation induces transitions from reversible to irreversible behaviour in both unjammed and jammed soft sphere packings. Well above isotropic jamming density (ϕJ\bf{\phi_J}), this transition corresponds to yielding. In the vicinity of the jamming point, up to a higher density limit we designate ϕJcyc{\bf \phi_J^{cyc}}, an unjammed phase emerges between a localised, \emph{absorbing} phase, and a diffusive, {\emph irreversible} phase. The emergence of the unjammed phase signals the shifting of the jamming point to higher densities as a result of annealing, and opens a window where shear jamming becomes possible for frictionless packings. Below ϕJ\bf{\phi_J}, two distinct localised states, termed point and loop reversibile, are observed. We characterise in detail the different regimes and transitions between them, and obtain a unified density-shear amplitude phase diagram

    An experimental study of the swelling properties of spherical hydro-gel immersed in water and the formulation of a simple theoretical model for its explanation

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    The mechanism of variation of mass and volume, through the absorption of water, by the most commonly used and abundantly available spherical hydro-gel beads of various colors has been studied. Immersing the beads in distilled water, both mass and volume were measured at regular intervals. By an analysis of mass-versus-time data, using standard theoretical methods, the mechanism of diffusion of water has been studied. Relaxation controlled transport was found to be the predominant process of diffusion of water into the materials under study. The diffusion coefficient has been determined for hydro-gels of different colors. Various swelling related parameters such as equilibrium water content, equilibrium swelling ratio, characteristic time, initial rate of water absorption etc. were determined for these hydro-gels. The maximum attainable mass and the maximum number of water molecules that can be attached to active polymer sites in a single bead have been calculated. In this regard, the number of such active sites per unit volume and mass of dry hydro-gel was determined. A theoretical model has been developed, based on the consideration of water absorption through the occupation of vacant polymer sites in a highly porous hydro-gel. Considerations of cylindrical and spherical pores in this model predicted almost the same swelling behavior. Expressions relating mass and volume with time have been formulated and they agreed well with experimental observations. The dependence of characteristic time () upon structural parameters have been established. Values of swelling related parameters have been determined by a numerical fitting of theoretical model to experimental data. The agreement of experimental findings with theoretical predictions has been depicted graphically

    An experimental study of the swelling properties of spherical hydro-gel immersed in water and the formulation of a simple theoretical model for its explanation

    Get PDF
    The mechanism of variation of mass and volume, through the absorption of water, by the most commonly used and abundantly available spherical hydro-gel beads of various colors has been studied. Immersing the beads in distilled water, both mass and volume were measured at regular intervals. By an analysis of mass-versus-time data, using standard theoretical methods, the mechanism of diffusion of water has been studied. Relaxation controlled transport was found to be the predominant process of diffusion of water into the materials under study. The diffusion coefficient has been determined for hydro-gels of different colors. Various swelling related parameters such as equilibrium water content, equilibrium swelling ratio, characteristic time, initial rate of water absorption etc. were determined for these hydro-gels. The maximum attainable mass and the maximum number of water molecules that can be attached to active polymer sites in a single bead have been calculated. In this regard, the number of such active sites per unit volume and mass of dry hydro-gel was determined. A theoretical model has been developed, based on the consideration of water absorption through the occupation of vacant polymer sites in a highly porous hydro-gel. Considerations of cylindrical and spherical pores in this model predicted almost the same swelling behavior. Expressions relating mass and volume with time have been formulated and they agreed well with experimental observations. The dependence of characteristic time () upon structural parameters have been established. Values of swelling related parameters have been determined by a numerical fitting of theoretical model to experimental data. The agreement of experimental findings with theoretical predictions has been depicted graphically

    Herbs Having Analgesic Activity

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    Healthcare maintains a high priority on pain management, and research to develop safer and more potent analgesics is ongoing. Natural goods, especially plants, have recently attracted renewed interest as potential sources of analgesic medications. In this study, various techniques are used to measure pain. The rich source of analgesics found in medicinal plants includes Moringa oleifera, Aloe barbadensis, Curcuma longa, Eugenia caryophyllata, Adhatoda vasica, Mentha piperita, Ocimum sanctum, Zingiber officinale, Lavandula angustifolia, Epilobium angustifolium, Dialium guineense, Sida acuta, Stylosanthes fruticose, Bougainvilla spectabilis, Ficus glomerata, Polyalithia longifolia, Calotropis gigantea, Tinospora cordifolia, Ageratina glabrata, Mangifera indica, Peperomia pellucida, Jatropha gossypifolia, Leonotis leonurus, Mimosa rubicaulis, Cussonia paniculate, Biebersteinia multifida, Alternanthera sessislis, Mentha arvensis, Oroxylum indicum, Tamarindus indica, Cucurbita maxima, Cucumis sativus, Emblica officinalis, Angiopteris evecta, Parastrephia lephidophylla, Peperomia pellucida, Scoparia dulcis, Ficus racemose, Eremostachys laciniata, Phlogacanthus thyrsiflorus, Kigelia pinnata, Molineria capitulate, Manihot esculenta, Ficus religiosa, Dalbergia sissoo, Grangea maderaspatana, Nothospondias staudtii, Rhodiola rosea, Juniperus communis, Erythrina variegate etc. The results reported in this review paper represent scientific knowledge that may be applied in the future to isolate potentially active molecules from some of these medicinal plants

    Clinicopathological spectrum of renal biopsies in children – A single center experience from Eastern India

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    Background: Renal diseases are common in childhood and they often present with diagnostic challenges. Renal biopsy is of major importance in diagnosing many renal diseases in children. The aim of this study was to evaluate the clinicopathological aspect of renal diseases underwent biopsy in children in a tertiary care teaching institute in Eastern India. Materials and methods: This cross sectional study was conducted on children (≀12 year) admitted with difficult to treat renal disorders in Pediatric ward and thorough evaluations confirmed the requirement of renal biopsy. Sixty one (61) children satisfying the inclusion and exclusion criteria were enrolled in our study. Period of study was from February 2021 to July 2022. Results: In this study, males were 31 and females were 30 in numbers. The mean age was 6.77± 3.42 years. The indications for renal biopsy were steroid resistant nephrotic syndrome (SRNS) (49.18%), systemic lupus erythematosus (SLE) (29.51%), acute glomerulonephritis (AGN) (16.39%), and others. The major bulks of histopathological findings revealed focal segmental glomerulosclerosis (FSGS), membranoproliferative glomerulonephritis (MPGN) and minimal change disease (MCD) in 45.9%, 32.8% and 13.1% respectively. Hypertension was present in 58.1% and hematuria in 64.5% of cases (p value 0.001). Conclusion: SRNS (49.18%) was the most common indication of renal biopsy and FSGS (45.9%) was the most common histopathological finding in our study. This study provides data on biopsy proven childhood renal disorders from this region

    Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

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    Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (Ό̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ÂŻ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ÂŻ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),Ό̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions