133 research outputs found
The global flood protection savings provided by coral reefs
Coral reefs can provide significant coastal protection benefits to people and property. Here we show that the annual expected damages from flooding would double, and costs from frequent storms would triple without reefs. For 100-year storm events, flood damages would increase by 91% to 400?M for each of these nations. Sea-level rise will increase flood risk, but substantial impacts could happen from reef loss alone without better near-term management. We provide a global, process-based valuation of an ecosystem service across an entire marine biome at (sub)national levels. These spatially explicit benefits inform critical risk and environmental management decisions, and the expected benefits can be directly considered by governments (e.g., national accounts, recovery plans) and businesses (e.g., insurance).We gratefully acknowledge support from the World Bank Wealth Accounting and Valuation of Ecosystems (WAVES) Program, the Lyda Hill Foundation, Science for Nature and People Partnership, Lloyd’s Tercentenary Research Foundation, a Pew Fellowship in Marine Conservation to MWB, the German International Climate Initiative (IKI) of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) and the Spanish Ministry of Economy and Innovation (BIA2014-59718- R)
Effects of cooling and internal wave motions on gas transfer coefficients in a boreal lake
Peer reviewe
Time dependent viscoelastic rheological response of pure, modified and synthetic bituminous binders
Bitumen is a viscoelastic material that exhibits both elastic and viscous components of response and displays both a temperature and time dependent relationship between applied stresses and resultant strains. In addition, as bitumen is responsible for the viscoelastic behaviour of all bituminous materials, it plays a dominant role in defining many of the aspects of asphalt road performance, such as strength and stiffness, permanent deformation and cracking. Although conventional bituminous materials perform satisfactorily in most highway pavement applications, there are situations that require the modification of the binder to enhance the properties of existing asphalt material. The best known form of modification is by means of polymer modification, traditionally used to improve the temperature and time susceptibility of bitumen. Tyre rubber modification is another form using recycled crumb tyre rubber to alter the properties of conventional bitumen. In addition, alternative binders (synthetic polymeric binders as well as renewable, environmental-friendly bio-binders) have entered the bitumen market over the last few years due to concerns over the continued availability of bitumen from current crudes and refinery processes. This paper provides a detailed rheological assessment, under both temperature and time regimes, of a range of conventional, modified and alternative binders in terms of the materials dynamic (oscillatory) viscoelastic response. The rheological results show the improved viscoelastic properties of polymer- and rubber-modified binders in terms of increased complex shear modulus and elastic response, particularly at high temperatures and low frequencies. The synthetic binders were found to demonstrate complex rheological behaviour relative to that seen for conventional bituminous binders
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Overlay Design for Cracked and Seated Portland Cement Concrete (PCC) Pavement--Interstate Route 710
This technical memorandum summarizes the analyses performed and the design recommended for the overlay thickness for a portion of Interstate 710 in Southern California. This design is a part of the “Long Life Pavement” system under consideration for this heavily trafficked freeway which serves the Port of Long Beach, California. The analyses consist of a series of finite element simulations performed on idealized representations of an asphalt concrete overlay on an existing plain, jointed, portland cement concrete (PCC) pavement in which the 8 inch thick existing slabs will be broken and seated prior to placement of the overlay. All of the finite element analyses were performed by Dr. Jeffrey Simons of Applied Research Associates (ARA) located in Sunnyvale, California.1 This report is complementary to the Technical Memorandum dated June 1999 which details the mix design and analysis and thickness design for the full-depth asphalt concrete section which will be placed in excavated sections under and adjacent to the bridge structures used as overcrossings for the freeway
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