Dye lasing in optically manipulated liquid aerosols

We report lasing in airborne, rhodamine B-doped glycerol-water droplets with diameters ranging between 7.7 and 11.0 mu m, which were localized using optical tweezers. While being trapped near the focal point of an infrared laser, the droplets were pumped with a Q-switched green laser. Our experiments revealed nonlinear dependence of the intensity of the droplet whispering gallery modes (WGMs) on the pump laser fluence, indicating dye lasing. The average wavelength of the lasing WGMs could be tuned between 600 and 630 nm by changing the droplet size. These results may lead to new ways of probing airborne particles, exploiting the high sensitivity of stimulated emission to small perturbations in the droplet laser cavity and the gain medium

Biodegradation of some agricultural residues by fungi in agitated submerged cultures

Digestibility of agricultural residues in animal feeding is deeply dependent on the amounts and types of their fibers. Biological treatment of agricultural residues is a new method for improvement of digestibility. Therefore, the capacity of a few fungi in biodegradation of some agricultural residues wasstudied. Losses of crude fiber (CF), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of wheat, barley, rice, wood, and pea straw were investigated in agitated submerged culture during biodegradation by fungi. Biodegradation of the plant residues is dependent on the plant and fungusspecies. The biodegradation order of plant residues was  pea>barley>wheat>rice>wood. A. terreus and T. reesei were more able to degrade the easy degradable plant residues. Rice and wood were degradedmore by Armillaria sp., Polyporus sp. and P. chrysosporium. Crude fiber, NDF and ADF of agricultural residues were reduced more by P. chrysosporium. Generally, the reduction of agricultural residues NDF by fungi was more than their ADF. However, Polyporus sp. decreased ADF of wheat straw more. Thus, for improvement of digestibility of agricultural residues, the treatment by white-rot fungi may be recommended

Optical bistability in one-dimensional doped photonic crystals with spontaneously generated coherence

We investigate optical bistability in a multilayer one-dimensional photonic crystal where the central layer is doped with Λ-type three-level atoms. We take into account the influence of spontaneously generated coherence when the lower atomic levels are sufficiently close to each other, in which case Kerr-type nonlinear response of the atoms is enhanced. We calculate the propagation of a probe beam in the defect mode window using the numerical nonlinear transfer matrix method. We find that Rabi frequency of a control field acting on the defect layer and the detuning of the probe field from the atomic resonance can be used to control the size and contrast of the hysteresis loop and the threshold of the optical bistability. In particular we find that at the optimal spontaneously generated coherence, a three orders of magnitude lower threshold can be achieved relative to the case without the coherence. © 2013 American Physical Society

Magnetic anisotropy of FePt: effect of lattice distortion and chemical disorder

We perform first principles calculations of the magnetocrystalline anisotropy energy in the five L10 FePt samples studied experimentally by Ding et al. [J. App. Phys. 97, 10H303 (2005)]. The effect of temperature-induced spin fluctuations is estimated by scaling the MAE down according to previous Langevin dynamics simulations. Including chemical disorder as given in experiment, the experimental correlation between MAE and lattice mismatch is qualitatively well reproduced. Moreover we determine the chemical order parameters that reproduce exactly the experimental MAE of each sample. We conclude that the MAE is determined by the chemical disorder rather than by lattice distortion.Comment: 5 pages, 3 figure

The role of (de-)essentialisation within siting conflicts: an interdisciplinary approach

Large-scale renewable energy and associated technologies (RET), such as high voltage power lines (HVPL), often meet opposition from the local communities living nearby. Research has suggested that one of the main aspects that might contribute to this is the fact that RET are represented as industrial and urban, and thus, as having a different essence from rural landscapes, where they are usually deployed and which are represented as natural and unspoilt. However, this 'hypothesis' of landscape essentialisation shaping people's responses to RET has not been explicitly examined. By drawing upon research from Social Psychology and Human Geography on essentialisation, we will examine if and how landscape (de-)essentialisation plays a role in people's responses to RET. Namely, by examining it as a rhetorical construction that can be strategically used to negotiate and legitimize given relations with place and associated responses to RET.Focus groups were conducted in the UK and Norway with members of local communities to be affected by the construction of HVPLs that will connect to new low carbon energy technologies. Analyses show that participants present British and Norwegian rural landscapes in general and HVPL as having two different essences, which justifies opposition to those infrastructures. However, analyses also show that essentialisation of the countryside is strategically used. Namely, participants also present the countryside in the place where they live as having more of the essence of the British or Norwegian countryside than other areas of the UK and Norway. In turn, this allows them to legitimize claims that whereas HVPL are 'out of place' in the countryside in general, they are more so in the place where they live.The implications of these results for the definition of acceptable locations for RET and for research on people-place relations and responses to place change, are discussed.info:eu-repo/semantics/acceptedVersio

Finite element computation of magnetohydrodynamic nanofluid convection from an oscillating inclined plate with radiative flux, heat source and variable temperature effects

The present work describes finite element computations for radiative magnetohydrodynamic convective Newtonian nanofluid flow from an oscillating inclined porous plate with variable temperature. Heat source/sink and buoyancy effects are included in the mathematical model. The problem is formulated by employing Tiwari-Das nanofluid model and two water - based nanofluids with spherical shaped metal nano particles as copper and alumina are considered. The Brinkman and Maxwell-Garnetts models are used for the dynamic viscosity and effective thermal conductivity of the nanofluids respectively. An algebraic flux model, the Rosseland diffusion approximation is adopted to simulate thermal radiative flux effects. The dimensionless, coupled governing partial differential equations are numerically solved via the finite element method with weak variational formulation by imposing initial and boundary conditions with a weighted residual scheme. A grid independence study is also conducted. The finite element solutions are reduced to known previous solutions in some limiting cases of the present investigation and are found to be in good agreement with published work. This investigation is relevant to electromagnetic nanomaterial manufacturing processes operating at high temperatures where radiation heat transfer is significant