Thermally activated barrier crossing and stochastic resonance of a flexible polymer chain in a piecewise linear bistable potential

We study the stochastic resonance (SR) of a flexible polymer chain crossing over a piecewise linear bistable potential. The dependence of signal to noise ratio $SNR$ on noise intensity $D$, coupling constant $k$ and polymer length $N$ is studied via two state approximation. We find that the response of signal to the background noise strength is significant at optimum values of $D_{opt}$, $k_{opt}$ and $N_{opt}$ which suggests novel means of manipulating proteins or vesicles. Furthermore, the thermally activated barrier crossing rate $r_{k}$ for the flexible polymer chain is studied. We find that the crossing rate $r_{k}$ exhibits an optimal value at an optimal coupling constant $k_{opt}$; $k_{opt}$ decreases with $N$. As the chain length $N$ increases, the escape rate for the center of mass $r_{k}$ monotonously decreases. On the other hand, the crossing rate for the portion of polymer segment $r_s$ increases and saturates to a constant rate as $N$ steps up.Comment: 16 pages, 9 figure

Energetics of a simple microscopic heat engine

We model a microscopic heat engine as a particle hopping on a one-dimensional lattice in a periodic sawtooth potential, with or without load, assisted by the thermal kicks it gets from alternately placed hot and cold thermal baths. We find analytic expressions for current and rate of heat flow when the engine operates at steady state. Three regions are identified where the model acts either as a heat engine or as a refrigerator or as neither of the two. At quasistatic limit both efficiency of the engine and coefficient of performance of the refrigerator go to that for Carnot engine and Carnot refrigerator, respectively. We investigate efficiency of the engine at two operating conditions (at maximum power and at optimum value with respect to energy and time) and compare them with those of the endoreversible and Carnot engines.Comment: 6 pages and 8 figure

Student’s classroom participation in English language teaching: The case of Gozamen General Secondary School in Grade 10-A

Student’s classroom participation in English language teaching: The case of Gozamen General Secondary School in Grade 10-A Author / Authors : Atalay Mesfin Aneteneh Page no. 204-217 Discipline : Education Script/language : Roman/ English Category : Research paper/Action research Keywords: English, Teaching Elementary, Training, Action research

The green, blue and grey water footprint of farm animals and animal products. Volume 2: Appendices

Contents Appendix I: Feed conversion efficiencies – in kg of feed (dry mass) per kg of output – per animal category and region Appendix II: Estimated consumption of feed per animal category and world region (103 ton dry mass/yr) Appendix III. Estimated consumption of feed per production system and world region (103 ton dry mass/yr) Appendix IV. Drinking and service water footprint per animal Appendix V. Water footprint of animals and animal products (m3/ton). Period 1996-200