Improving market intelligence for organic horticulture in Wales

The organic market in the UK reached a value of £1.015 billion during the 2002/2003 financial year. The market for organic food and drink in Wales and the surrounding counties is estimated to account for 6.3 per cent of this, a total of £64 million. Assuming the proportion of sales of organic fruit and vegetables in Wales is the same as the UK as a whole then the market for organic fruit and vegetables in Wales can be valued at £20.5 million for the financial year 2002/03. The area of fully organic horticultural land in Wales in April 2003 was 513 hectares with 102 producers involved in organic fruit and vegetable production. Of these producers, over 60 per cent were mixed farms encompassing livestock and/or cereals alongside horticulture. The estimated farm-gate value of Welsh produced organic fruit and vegetables was £1.8 million, approaching 5 per cent of the total UK farm-gate value of £43.96 million. Organic horticultural production accounts for a significant proportion - 10 per cent - of the total horticultural land in Wales. In comparison, organic horticulture in the UK as a whole accounts for just 4 per cent of the total horticultural land. Interviews with Welsh growers identified a number of key challenges facing them including market access, lack of producer co-operation, increased competition (particularly from within the UK) and availability of labour. At the beginning of 2003, 103 licensed organic processing operations were operating in Wales with approximately one-third handling fruit and vegetables. The main constraints to increasing the utilisation of domestic produce were identified as continuity, quality, accessibility and reliability of supply. Key recommendations to help overcome many of the challenges identified are included in Chapter 6 - Conclusions and Recommendations. Fruit and vegetables are a key entry point for consumers beginning to buy organic food. Welsh consumers are less ‘put-off’ by the price of organic food than consumers across the UK as a whole. Supporting the local farmers is particularly important to the Welsh consumer, with 35 per cent of the Welsh organic buying public stating that it was important to support local farmers, compared to 16 per cent in the UK overall

Improving market intelligence for organic dairy production in Wales

This report was commissioned by Farming Connect via the Organic Centre Wales and was written and produced by the Soil Association Producer Services Department in February 2003. It has been made possible with the kind co-operation of the Federation of Milk Groups. Objectives 1. To develop a system of monthly data collection for Wales which is compatible with nation-wide data collection 2. Collection of historic data on dairy production in Wales (1997 – 2002) 3. Projections for future production and processing levels (2003 – 2006) 4. Identification of potential areas of growt

Microscopic Investigation of Vortex Breakdown in a Dividing T-Junction Flow

3D-printed microfluidic devices offer new ways to study fluid dynamics. We present the first clear visualization of vortex breakdown in a dividing T-junction flow. By individual control of the inflow and two outflows, we decouple the effects of swirl and rate of vorticity decay. We show that even slight outflow imbalances can greatly alter the structure of vortex breakdown, by creating a net pressure difference across the junction. Our results are summarized in a dimensionless phase diagram, which will guide the use of vortex breakdown in T-junctions to achieve specific flow manipulation.Comment: 5 pages, 5 figure

Extensional rheology and elastic instabilities of a wormlike micellar solution in a microfluidic cross-slot device

Wormlike micellar surfactant solutions are encountered in a wide variety of important applications, including enhanced oil recovery and ink-jet printing, in which the fluids are subjected to high extensional strain rates. In this contribution we present an experimental investigation of the flow of a model wormlike micellar solution (cetyl pyridinium chloride and sodium salicylate in deionised water) in a well-defined stagnation point extensional flow field generated within a microfluidic cross-slot device. We use micro-particle image velocimetry (m-PIV) and full-field birefringence microscopy coupled with macroscopic measurements of the bulk pressure drop to make a quantitative characterization of the fluid’s rheological response over a wide range of deformation rates. The flow field in the micromachined cross-slot is first characterized for viscous flow of a Newtonian fluid, and m-PIV measurements show the flow field remains symmetric and stable up to moderately high Reynolds number, Re z 20, and nominal strain rate, _3nom z 635 s1. By contrast, in the viscoelastic micellar solution the flow field remains symmetric only for low values of the strain rate such that _3nom # lM1, where lM ¼ 2.5 s is the Maxwell relaxation time of the fluid. In this stable flow regime the fluid displays a localized and elongated birefringent strand extending along the outflow streamline from the stagnation point, and estimates of the apparent extensional viscosity can be obtained using the stressoptical rule and from the total pressure drop measured across the cross-slot channel. For moderate deformation rates (_3nom $ lM1) the flow remains steady, but becomes increasingly asymmetric with increasing flow rate, eventually achieving a steady state of complete anti-symmetry characterized by a dividing streamline and birefringent strand connecting diagonally opposite corners of the cross-slot. Eventually, as the nominal imposed deformation rate is increased further, the asymmetric divided flow becomes time dependent. These purely elastic instabilities are reminiscent of those observed in crossslot flows of polymer solutions, but seem to be strongly influenced by the effects of shear localization of the micellar fluid within the microchannels and around the re-entrant corners of the cross-slot

Unified Description of Aging and Rate Effects in Yield of Glassy Solids

The competing effects of slow structural relaxations (aging) and deformation at constant strain rate on the shear yield stress $\tau^y$ of simple model glasses are examined using molecular simulations. At long times, aging leads to a logarithmic increase in density and $\tau^y$. The yield stress also rises logarithmically with rate, but shows a sharp transition in slope at a rate that decreases with increasing age. We present a simple phenomenological model that includes both intrinsic rate dependence and the change in properties with the total age of the system at yield. As predicted by the model, all data for each temperature collapse onto a universal curve.Comment: 4 pages, 3 figure