Rural Resource Centre (RRC) business model: A new agri-based knowledge hub

Poster prepared for a share fair, Addis Ababa, May 201

Optimal barrier subdivision for Kramers' escape rate

We examine the effect of subdividing the potential barrier along the reaction coordinate on Kramers' escape rate for a model potential. Using the known supersymmetric potential approach, we show the existence of an optimal number of subdivisions that maximises the rate.Comment: 8 pages, 3 figures, To appear in Pramana - J. Phys, Indi

Noise-created bistability and stochastic resonance of impurities diffusing in a semiconductor layer

We investigate the dynamics of impurities walking along a semiconductor layer assisted by thermal noise of strength $D$ and external harmonic potential $V(x)$. Applying a nonhomogeneous hot temperature in the vicinity of the potential minimum may modify the external potential into a bistable effective potential. We propose the ways of mobilizing and eradicating the unwanted impurities along the semiconductor layer. Furthermore, the thermally activated rate of hopping for the impurities as a function of the model parameters is studied in high barrier limit. Via two state approximation, we also study the stochastic resonance (SR) of the impurities dynamics where the same noise source that induces the dynamics also induces the transition from mono-stable to bistable state which leads to SR in the presence of time varying field.Comment: Accepted for publication in EPJ

Fabrication and Characterization of Electrospun Drug-eluting Nanofibers from Polycaprolactone/Chitosan Blends

Electrospinning has emerged as a widely accepted technique with ability to produce nanofibers that can be employed in many biomedical applications. In particular, drug-eluting nanofibers have become very popular in controlled release of small molecule drugs. In this study, nanofibers from blends of polylactocaprone (PCL) and chitosan (CHI) were electrospun with the ability to load a model drug, acetylsalicylic acid (ASA), at 10 wt%. PCL/CHI fibers exhibited smooth surface morphology at polymer compositions ranging from 100/0 to 40/60 with or without the incorporation of ASA. Mechanical properties suggested a brittle failure mechanism for fibers loaded with drug. In vitro drug release study displayed a controlled release profile of ASA up to 48 h. Our study aims to explore the drug-polymer interactions and their effects on fiber structure, mechanical properties and drug release profile.Cockrell School of Engineerin

Electric vehicle possibilities using low power and light weight range extenders

Electric cars have the disadvantage of a limited range, and drivers may experience a range anxiety. This range anxiety can be solved by adding a range extender. But, the range extender should be light so as not to significantly increase the weight of the original vehicle. In urban areas with dense traffic (usually developing countries), the average speed around cities is typically lower than 50km/h. This means, the rolling resistance losses are more important than aerodynamic losses, and a weight reduction results in a bigger electrical range. Therefore, smaller and lighter range extenders are of much interest. The contribution of this paper is to indicate the possibility of range extenders with less than 25 kg with a capacity of 150 to 200 cc to suit a condition where weight counts. In this paper, the cost, environmental and grid impacts of going electric are also discussed. The effect of high altitude and driving style on the performance of an electric vehicle is assessed. The challenges and opportunities of vehicle electrification between countries with decarbonated power generation and fossil fuel dominated power generation are highlighted. Throughout the article, the case of Ethiopia is taken as an example

A spatial memory signal shows that the parietal cortex has access to a craniotopic representation of space

Humans effortlessly establish a gist-like memory of their environment whenever they enter a new place, a memory that can guide action even in the absence of vision. Neurons in the lateral intraparietal area (LIP) of the monkey exhibit a form of this environmental memory. These neurons respond when a monkey makes a saccade that brings the spatial location of a stimulus that appeared on a number of prior trials, but not on the present trial, into their receptive fields (RFs). The stimulus need never have appeared in the neuron’s RF. This memory response is usually weaker, with a longer latency than the neuron’s visual response. We suggest that these results demonstrate that LIP has access to a supraretinal memory of space, which is activated when the spatial location of the vanished stimulus can be described by a retinotopic vector from the center of gaze to the remembered spatial location