The proven effectiveness of highway crossing infrastructure to mitigate wildlife-vehicle collisions with large animals has made it a preferred method for increasing motorist and animal safety along road networks around the world. The crossing structures also provide safe passage for small-and medium-sized wildlife. Current methods to build these structures use concrete and steel, which often result in high costs due to the long duration of construction and the heavy machinery required to assemble the materials. Recently, engineers and architects are finding new applications of fiber-reinforced polymer (FRP) composites, due to their high strength-to-weight ratio and low life-cycle costs. This material is better suited to withstand environmental elements and the static and dynamic loads required of wildlife infrastructure. Although carbon and glass fibers along with new synthetic resins are most commonly used, current research suggests an increasing incorporation and use of bio-based and recycled materials. Since FRP bridges are corrosion resistant and hold their structural properties over time, owners of the bridge can benefit by reducing costly and time-consuming maintenance over its lifetime. Adapting FRP bridges for use as wildlife crossing structures can contribute to the long-term goals of improving motorist and passenger safety, conserving wildlife and increasing cost efficiency, while at the same time reducing plastics in landfills.Sustainability 2020, 12, 1557 2 of 15 connectivity for particular species [8]. Although usually more expensive than underpasses [3], overpasses are also frequently chosen by some species [9].The length and the width of overpasses continue to challenge engineers, architects and ecologists. Some overpasses are required to span six or more lanes, including Canada Highway 1 in Yoho National Park and Interstate Highway 90 in the Cascade Mountains of Washington. Some newer designs are anticipated to exceed lengths spanning 10-12 lanes. The proposed wildlife overpass on Highway 101 in Liberty Canyon, California, will require bridge spans up to 60 meters (m) and be the largest wildlife overpass ever built, as seen in Figure 1 [10]. Common widths of overpasses have been designed from 30 to 60 m and even wider. These geometry requirements can result in massive and relatively uneconomical structures. Many existing wildlife overpass structures are constructed to support heavy loads that incorporate excessive backfill to host native habitats, such as forests. This design feature adds substantial weight to the static and environmental loads the structure is required to support. Supporting these loads over multi-lane roadways further results in relatively high costs compared to underpasses or other less-effective mitigation measures. Because of the costs, the siting of these structures is especially challenging as they can only be provided sparingly across a large area where WVCs commonly create safety issues for drivers. Recent price tags for wildlife overpasses near Banff, Alberta, Canada, co...

A convectively cooled, recirculating thermoelectric generator based on β″ alumina has been designed and operated over the temperature range of 400–600 °C. The design employs a stainless-steel wick and flame sprayed molybdenum electrodes and the unit can be assembled and operated with ease. A full treatment of all thermal and electrical flows is given and theoretical efficiencies of 10%–15% are predicted. Critical parameters are the internal resistance and radiation coefficients for thermal losses, while it is also shown that the flow of sodium within the electrode and the geometry of the evaporating and condensing surfaces is of importance in limiting the measured efficiency to 1%–3%. Units have been operated for up to 3000 h.