NDICEA as a user friendly model tool for crop rotation planning in organic farming

For organic farming systems, the challenge is to become more specific in practices to maintain high standards in sustainability. Soil processes need to be clearly understood if rotations and manure applications are to become more precise. Simulation models like the NDICEA model help in the design and maintenance of these farming systems. These models play a key-role in the design of organic precision farming. The NDICEA model has been calibrated for a number of long-term crop rotation experiments. Recently, the model was validated using research data from more than 35 organic farms all over the country. The model is used to calculate soil-specific mineralization rates in precision applications. In a new easy-to-use application, it was developed to design crop rotations and evaluate performance of crop rotations. This application is used to evaluate the sustainability of farming systems

Using ultra-short pulses to determine particle size and density distributions

We analyze the time dependent response of strongly scattering media (SSM) to ultra-short pulses of light. A random walk technique is used to model the optical scattering of ultra-short pulses of light propagating through media with random shapes and various packing densities. The pulse spreading was found to be strongly dependent on the average particle size, particle size distribution, and the packing fraction. We also show that the intensity as a function of time-delay can be used to analyze the particle size distribution and packing fraction of an optically thick sample independently of the presence of absorption features. Finally, we propose an all new way to measure the shape of ultra-short pulses that have propagated through a SSM.Comment: 15 pages, 29 figures, accepted for publication in Optics Express will update with full reference when it is availabl

A Third Star in the T Tauri System

New speckle-holographic images of the T Tauri Infrared Companion (T Tauri IRC; T Tauri S) reveal it to be a double system with a sky-projected separation of 0".05, corresponding to a linear distance of 7 AU. The presence of this third star may account for the relative paucity of dust surrounding the IRC.Comment: 5 pages in AASTeX preprint form, including one grayscale figur

Continuous-flow laboratory simulation of stream water quality changes downstream of an untreated wastewater discharge.

In regions of the world with poor provision of wastewater treatment, raw sewage is often discharged directly into surface waters. This paper describes an experimental evaluation of the fate of two organic chemicals under these conditions using an artificial channel cascade fed with a mix of settled sewage and river water at its upstream end and operated under continuous steady-state conditions. The experiments underpin an environmental risk assessment methodology based on the idea of an “impact zone” (IZ) – the zone downstream of wastewater emission in which water quality is severely impaired by high concentrations of unionised ammonia, nitrite and biochemical oxygen demand (BOD). Radiolabelled dodecane-6-benzene sulphonate (DOBS) and aniline hydrochloride were used as the model chemical and reference compound respectively. Rapid changes in 14C counts were observed with flow-time for both these materials. These changes were most likely to be due to complete mineralisation. A dissipation half-life of approximately 7.1 h was observed for the 14C label with DOBS. The end of the IZ was defined as the point at which the concentration of both unionised ammonia and nitrite fell below their respective predicted no-effect concentrations for salmonids. At these points in the cascade, approximately 83 and 90% of the initial concentration of 14C had been removed from the water column, respectively. A simple model of mineral nitrogen transformations based on Michaelis–Menten kinetics was fitted to observed concentrations of NH4, NO2 and NO3. The cascade is intended to provide a confirmatory methodology for assessing the ecological risks of chemicals under direct discharge co

A gain-coefficient switched Alexandrite laser

We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.Comment: 8 pages, 5 figure

Radio Emission from SN 2001gd in NGC 5033

We present the results of monitoring the radio emission from the Type IIb supernova SN 2001gd between 2002 February 8 and 2002 October 28. Most of the data were obtained using the Very Large Array at the five wavelengths of $\lambda \lambda$1.3 cm (22.4 GHz), 2.0 cm (14.9 GHz), 3.6 cm (8.44 GHz), 6.2 cm (4.86 GHz), and 21 cm (1.4 GHz). Observations were also made with Giant Meterwave Radio Telescope at $\lambda$21 cm (1.4 GHz). The object was discovered optically well after maximum light, making any determination of the early radio evolution difficult. However, subsequent observations indicate that the radio emission has evolved regularly in both time and frequency and is well described by the SN shock/circumstellar medium interaction model.Comment: 16 pages 2 figures to appear in Astrophysical Journa

One-Watt level mid-IR output, singly resonant, continuous-wave optical parametric oscillator pumped by a monolithic diode laser

We report more than 1.1 Watt of idler power at 3373 nm in a singly resonant optical parametric oscillator (SRO), directly pumped by a single-frequency monolithic tapered diode laser. The SRO is based on a periodically poled MgO:LiNbO3 crystal in a four mirror cavity and is excited by 8.05 W of 1062 nm radiation. The SRO pump power at threshold is 4 W. The internal slope-efficiency and conversion efficiency reach 89% and 44% respectively. The signal and idler waves are temperature tuned in the range of 1541 to 1600 nm and 3154 to 3415 nm respectively. To the best of our knowledge, this is the highest output obtained for a diode pumped optical parametric oscillator (OPO), and the first time a SRO is directly pumped by a monolithic tapered diode laser

Modern Slavery Disclosure Regulation and Global Supply Chains : Insights from Stakeholder Narratives on the UK Modern Slavery Act

Open access via Springer compact agreement Acknowledgements The authors would like to thank and acknowledge CPA Australia for partially supporting their data collection.Peer reviewedPublisher PD