Evaluation of greenwaste mulch to control runoff quality from landfill sites during frequent storms

This paper describes a preliminary evaluation of two types of greenwaste (fresh and aged) used as a mulch layer to control runoff from disturbed landfill areas. Fresh greenwaste refers to woody and herbaceous garden waste that has been recently collected, chopped and shredded. Aged greenwaste is greenwaste which has been stockpiled for 18 months. We used rainfall simulator tests to investigate two aspects: (1) the performance of greenwaste mulch in reducing runoff during designed storm events with a high frequency of occurrence and (2) the release of pollutants via runoff as total suspended solids (TSS) and total organic carbon (TOC) during rain. Rainfall of <5-year average recurrence interval (ARI) was generally applied, consistent with stormwater compliance requirements for many Australian landfills. TOC released from fresh greenwaste material was higher in concentration than from aged greenwaste. However when used as a 10cm-deep mulch layer, fresh greenwaste was able to completely prevent runoff, even when tested under rainfalls up to 50 year ARI duration. An equivalent mulch layer of aged greenwaste was also effective in reducing runoff volume and TSS concentration compared with the bare soil during a 3.5-year ARI rainfall, but mean TOC concentration was higher. Based on these preliminary results, fresh greenwaste mulching of bare soils is an attractive option to control runoff and erosion from areas subject to intermittent landfill operations and worthy of further investigations

Dynamic Magnetization-Reversal Transition in the Ising Model

We report the results of mean field and the Monte Carlo study of the dynamic magnetization-reversal transition in the Ising model, brought about by the application of an external field pulse applied in opposition to the existing order before the application of the pulse. The transition occurs at a temperature T below the static critical temperature T_c without any external field. The transition occurs when the system, perturbed by the external field pulse competing with the existing order, jumps from one minimum of free energy to the other after the withdrawal of the pulse. The parameters controlling the transition are the strength h_p and the duration Delta t of the pulse. In the mean field case, approximate analytical expression is obtained for the phase boundary which agrees well with that obtained numerically in the small Delta t and large T limit. The order parameter of the transition has been identified and is observed to vary continuously near the transition. The order parameter exponent beta was estimated both for the mean field (beta =1) and the Monte Carlo beta = 0.90 \pm 0.02 in two dimension) cases. The transition shows a "critical slowing-down" type behaviour near the phase boundary with diverging relaxation time. The divergence was found to be logarithmic in the mean field case and exponential in the Monte Carlo case. The finite size scaling technique was employed to estimate the correlation length exponent nu (= 1.5 \pm 0.3 in two dimension) in the Monte Carlo case.Comment: 13 pages, latex, 8 figure

Length and time scale divergences at the magnetization-reversal transition in the Ising model

The divergences of both the length and time scales, at the magnetization- reversal transition in Ising model under a pulsed field, have been studied in the linearized limit of the mean field theory. Both length and time scales are shown to diverge at the transition point and it has been checked that the nature of the time scale divergence agrees well with the result obtained from the numerical solution of the mean field equation of motion. Similar growths in length and time scales are also observed, as one approaches the transition point, using Monte Carlo simulations. However, these are not of the same nature as the mean field case. Nucleation theory provides a qualitative argument which explains the nature of the time scale growth. To study the nature of growth of the characteristic length scale, we have looked at the cluster size distribution of the reversed spin domains and defined a pseudo-correlation length which has been observed to grow at the phase boundary of the transition.Comment: 9 pages Latex, 3 postscript figure

Mean field and Monte Carlo studies of the magnetization-reversal transition in the Ising model

Detailed mean field and Monte Carlo studies of the dynamic magnetization-reversal transition in the Ising model in its ordered phase under a competing external magnetic field of finite duration have been presented here. Approximate analytical treatment of the mean field equations of motion shows the existence of diverging length and time scales across this dynamic transition phase boundary. These are also supported by numerical solutions of the complete mean field equations of motion and the Monte Carlo study of the system evolving under Glauber dynamics in both two and three dimensions. Classical nucleation theory predicts different mechanisms of domain growth in two regimes marked by the strength of the external field, and the nature of the Monte Carlo phase boundary can be comprehended satisfactorily using the theory. The order of the transition changes from a continuous to a discontinuous one as one crosses over from coalescence regime (stronger field) to nucleation regime (weaker field). Finite size scaling theory can be applied in the coalescence regime, where the best fit estimates of the critical exponents are obtained for two and three dimensions.Comment: 16 pages latex, 13 ps figures, typos corrected, references adde

Generation of wakefields by whistlers in spin quantum magnetoplasmas

The excitation of electrostatic wakefields in a magnetized spin quantum plasma by the classical as well as the spin-induced ponderomotive force (CPF and SPF, respectively) due to whistler waves is reported. The nonlinear dynamics of the whistlers and the wakefields is shown to be governed by a coupled set of nonlinear Schr\"{o}dinger (NLS) and driven Boussinesq-like equations. It is found that the quantum force associated with the Bohm potential introduces two characteristic length scales, which lead to the excitation of multiple wakefields in a strongly magnetized dense plasma (with a typical magnetic field strength $B_{0}\gtrsim10^{9}$ T and particle density $n_{0}\gtrsim10^{36}$ m$^{-3}$), where the SPF strongly dominates over the CPF. In other regimes, namely $B_{0}\lesssim10^{8}$ T and $\ n_{0}\lesssim10^{35}$ m$^{-3}$, where the SPF is comparable to the CPF, a plasma wakefield can also be excited self-consistently with one characteristic length scale. Numerical results reveal that the wakefield amplitude is enhanced by the quantum tunneling effect, however it is lowered by the external magnetic field. Under appropriate conditions, the wakefields can maintain high coherence over multiple plasma wavelengths and thereby accelerate electrons to extremely high energies. The results could be useful for particle acceleration at short scales, i.e. at nano- and micrometer scales, in magnetized dense plasmas where the driver is the whistler wave instead of a laser or a particle beam.Comment: 8 pages, 2 figures; Revised version to appear in Physics of Plasmas (Dec. 2010 issue

Fluctuation Cumulant Behavior for the Field-Pulse Induced Magnetisation-Reversal Transition in Ising Models

The universality class of the dynamic magnetisation-reversal transition, induced by a competing field pulse, in an Ising model on a square lattice, below its static ordering temperature, is studied here using Monte Carlo simulations. Fourth order cumulant of the order parameter distribution is studied for different system sizes around the phase boundary region. The crossing point of the cumulant (for different system sizes) gives the transition point and the value of the cumulant at the transition point indicates the universality class of the transition. The cumulant value at the crossing point for low temperature and pulse width range is observed to be significantly less than that for the static transition in the same two-dimensional Ising model. The finite size scaling behaviour in this range also indicates a higher correlation length exponent value. For higher temperature and pulse width range, the transition seems to fall in a mean-field like universality class.Comment: 5 pages, 8 eps figures, thoroughly revised manuscript with new figures, accepted in Phys. Rev. E (2003

Crystals for Demazure Modules of Classical Affine Lie Algebras

We study, in the path realization, crystals for Demazure modules of affine Lie algebras of types $A^{(1)}_n,B^{(1)}_n,C^{(1)}_n,D^{(1)}_n, A^{(2)}_{2n-1},A^{(2)}_{2n}, and D^{(2)}_{n+1}$. We find a special sequence of affine Weyl group elements for the selected perfect crystal, and show if the highest weight is l\La_0, the Demazure crystal has a remarkably simple structure.Comment: Latex, 28 page

LOCAL PROPERTY OF A FACTORED FOURIER SERIES USING ABSOLUTE NORLUND INDEXED-SUMMABILITY

In this paper we have established a theorem on the local property of absolute Norlund indexed-summability of  Factored Fourier series

FACTORS INFLUENCING SOUTHERN DAIRY FARMERS' CHOICE OF MILK HANDLERS

Survey data of 2,538 dairy farmers located in 12 southern states were used to analyze the factors influencing farmers' choice of milk handlers. Results from a qualitative response model indicate that a combination of price and non-price factors contribute to dairy farmers' attitudes toward their milk handlers. Specifically, the decision to change milk handlers was significantly influenced by prices paid and deductions charged. However, non-price factors including field services, friendly personnel, and loyalty to a handler contributed to the longer term affiliation of dairy farmers with their milk handlers.Dairy farmers, Milk handlers, Market channels, Qualitative response, Marketing, Agribusiness,

Exploring Short-GRB afterglow parameter space for observations in coincidence with gravitational waves

Short duration Gamma Ray Bursts(SGRB) and their afterglows are among the most promising electro-magnetic (EM) counterparts of Neutron Star (NS) mergers. The afterglow emission is broadband, visible across the entire electro-magnetic window from $\gamma$-ray to radio frequencies. The flux evolution in these frequencies is sensitive to the multi-dimensional afterglow physical parameter space. Observations of gravitational wave (GW) from BNS mergers in spatial and temporal coincidence with SGRB and associated afterglows can provide valuable constraints on afterglow physics. We run simulations of GW-detected BNS events and assuming all of them are associated with a GRB jet which also produces an afterglow, investigate how detections or non-detections in X-ray, optical and radio frequencies can be influenced by the parameter space. We narrow-down the regions of afterglow parameter space for a uniform top-hat jet model which would result in different detection scenarios. We list inferences which can be drawn on the physics of GRB afterglows from multi-messenger astronomy with coincident GW-EM observations.Comment: Published in MNRA