Root temperature and energy consumption at different cable depths in electrically heated substrates

A finite element method-based model of a substrate heated by an electric heating cable buried in a thermal isolated container was experimentally validated with root mean square error values of root zone temperature ranging 0.25 to 0.62 ºC. The two-dimensional transient model allowed variations in the physical properties of the substrate with temperature, water content and depth. The operation of nine configurations of a heating cable buried in sand at different depths (50 to 450 mm, at 50 mm intervals) at 200 mm spacing was simulated and assessed. The validated model was used to perform 24-h simulations applying boundary conditions, and substrate moisture content was experimentally obtained at a mean substrate surface temperature of 13.98 ºC. Such simulations reproduced the operation of the heating system by setting a reference temperature of 20 ºC at the control point in the root zone. Burying the heating cable in the surface layers of the substrate caused large temperature gradients and high heat losses through the substrate surface. Accordingly, average temperature in the root zone increased with heating cable depth, up to the 200 mm depth. For greater depths, temperature in the root zone was constant. The ON/OFF control was most effective with the heating cable buried in the root zone and at control point temperatures of 20 ± 1 ºC. Burying the heating cable in the surface layers required higher energy consumption, up to 28 % at 50 mm. The most efficient heating cable depth was 350 mm, with a daily energy consumption of 6750 kJ m-2

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Passage of inanga (Galaxias maculatus) over artificial ramps as a means of restoring upstream access to stream habitat

The effects of substrate type, flow rate, and slope on fish passage over artificial ramps was evaluated for inanga (Galaxias maculatus); a small diadromous fish native to New Zealand, Australia, Tasmania, Lord Howe Island, Chatham Island, Chile, Argentina, and the Falkland Islands. Five substrate types (smooth, corrugated, herring-bone baffle, and two plastic moulded cores of ground drainage products Polyfo® and Stripdrain®) were tested on slopes of 3 - 5 % and flows of 4 - 6 ls-1. Slope, fish size, and substrate type each had a significant influence on the mean distances swum. Stripdrain® was the most effective substrate type, enabling the greatest distances to be achieved and a maximum vertical elevation of 0.39 m to be attained. The results of this study have further highlighted the potential for ramps to provide fish passage past small in-stream barriers, as well as the need to refine ramp slopes and lengths in order to meet the specific barrier remediation needs