Tracer dynamics in dense soft-colloidal suspensions: From free diffusion to hopping

Tracking of individual particle and studying their motion serves as a direct means to understand the dynamics in crowded and complex environments. In this study, the dynamics of tracer particles in the matrix of dense soft-colloidal suspensions in fluid phase is studied by means of dissipative particle dynamics simulations. By considering relatively large tracer (three times that of colloid) we systematically explore the interplay between the environment in which the tracer undergoes motion and interaction with the environment on the dynamics for temperatures close to the thermodynamic freezing transition where the effect of pair-wise interaction is significant compared to thermal energy. To this end we consider three fluid systems differing in the degree of softness (i.e., ultra-soft, intermediate, and hard) of the constituent colloidal particles, also change tracer types in the sense that we vary the degree of softness of the tracer w.r.t. colloids from ultra-soft to very hard. It is found that for tracer in ultra-soft colloidal fluid, at long times, the motion is diffusive for all tracer types, however the relaxation time (or diffusion constant) increases (or decreases) with increasing hardness of tracer at a given temperature. Interestingly, for tracer in hard colloidal fluid, the motion changes from a free diffusion (continuous trajectory) to that of hopping where there is intermittent jumps following a long period of localized vibrations and consequently displacement distribution function show higher order peaks indicating different dynamics at different time (or length) scales.Comment: 11 pages, 10 figure

Risk analaysis of ethanol blending fuel in refinery industry using event tree analysis and Topsis method

Chemicals have always posed risks including fire, explosion, and the release of harmful substances in process industries like the Petroleum Industry. The occurrence of such catastrophes has a significant impact on the resources for finances and daily living. In this research paper, the major safety-related causes and effects are identified through event tree analysis based on accidents and incidents while using ethanol as fuel. For this purpose, the accident and incident data collected so far while using ethanol in the fuel industry, detailed information about ethanol, and even tree analysis. The event tree analysis (ETA) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) analysis method is utilized to Identifying an initiating event of interest of accident. The event tree\u27s structure also aids the analyst in identifying the locations where additional protocols or safety measures are required to mitigate accidents or lower their frequency

Traditional Uses of Some Medicinal Plants by tribals of Gangaraju Madugula Mandal of Visakhapatnam District, Andhra Pradesh

During the years 2007-2008 several field trips were conducted to document the ethnomedicinal remedies for 47 diseases with 90 plant species of Angiosperms from three major tribes viz: Bagatas, Konda Doras and Valmikis who have been residing in Gangaraju Madugula Mandal of Visakhapatnam district. The plants were deposited as herbarium specimens in Andhra University, Visakhapatnam, India

Effect of topology on the collapse transition and the instantaneous shape of a model heteropolymer

The effect of topology on the collapse transition and instantaneous shape of an energy polydisperse polymer (a model heteropolymer) is studied by means of computer simulations. In particular, we consider three different chain topology, namely, linear (L), ring (R) and trefoil knot (T). The heteropolymer is modeled by assigning each monomer an interaction parameter, $\varepsilon_i$, drawn randomly from a Gaussian distribution. Through chain size scaling the transition temperature, $\theta$, is located and compared among the chains of different topogies. The influence of topology is reflected in the value of $\theta$ and observed that $\theta(\text{L}) > \theta(\text{R}) > \theta(\text{T})$ in a similar fashion to that of the homopolymer counterpart. Also studied chain size distributions, and the shape changes across the transition temperature characterised through shape parameters based on the eigenvalues of the gyration tensor. It is observed that, for the model heteropolymer, in addition to chain topology the $\theta$-temperature also depends on energy polydispersity.Comment: 10 pages, 9 figure

Avvaiyar's thoughts on life guide

Among the poets of Tamil literature, Avvaiyar has carved a niche for himself by his ability to express himself through knowledge, personality, erudition and erudition. In his history of Tamil literature, M. Arunachalam mentions that there lived six women poets in the name of Avvaiyar. Avvaiyar, who wrote books like Aathisudi, Konrai Vendan, Nalvazhi and Moothurai during the Chola period, is the avvaiyar of our article. It is a Tamil law book and derives its name from the fact that it describes the good ways that people should follow in their lives in Nerisai Venba. This article goes on to tell the family and the individual in many ways that the society should avoid wasteful expenditures and spend on the budget and that the air tip is the best and the sweet word is the best

Transport properties of polydisperse hard sphere fluid: Effect of distribution shape and mass scaling

A model polydisperse fluid represents many real fluids such as colloidal suspensions and polymer solutions. In this study, considering a concentrated size-polydisperse hard sphere fluid with size derived from two different distribution functions, namely, uniform and Gaussian and explore the effect of polydispersity and mass scaling on the transport properties in general. A simple analytical solution based on the Boltzmann transport equation is also presented (together with the solution using Chapman-Enskog (CE) method) using which various transport coefficients are obtained. The central idea of our approach is the realization that, in polydisperse system, the collision scattering cross section is proportional to a random variable \textit{z} which is equal to the sum of two random variables $\sigma_i$ and $\sigma_j$ (representing particle diameters), and the distribution of \textit{z} can be written as the convolution of the two distributions $P(\sigma_i)$ and $P(\sigma_j)$. The obtained transport coefficients are expressed as explicit function of polydispersity index, $\delta$, and their dependence on the nature of particle size distribution is explored. It is observed that in the low polydispersity limit, the transport coefficients are found to be insensitive to the type of size distribution functions considered. The analytical results (for diffusion coefficients and thermal conductivity) obtained using Chapman-Enskog method and our simple analytical approach agrees well with the simulation. However, for shear viscosity, our analyical approach agress for $\delta \le 20\%$, while it agrees upto $\delta \approx 40\%$ with the result obtained using CE-method (in the limit $\delta \rightarrow 0$). Interestingly, the effect of scaling mass (i.e., mass proportional to the particle size and thus a random variable) produces no significant qualitative difference.Comment: 10 pages, 7 figure