Creep of a C-S-H gel: a micromechanical approach

Both clays and calcium silicate hydrates(the main hydration products of Portland cements) exhibit a microstructure made up of lamellar particles. The microscopic mechanism responsible for the macroscopic creep of such materials is often described as the relative sliding of the sheets. This paper proposes a micromechanical approach to estimate the macroscopic creep behavior rising from this microscopic mechanism. The asymptotic evolution of creep at both short- and long-term is especially investigated. More precisely, a non-vanishing initial elastic strain is retrieved. At long-term, a threshold on porosity appears. At lower porosities, the creep evolution admits an asymptotic strain. At higher porosities, it admits an asymptotic strain rate.<br>Argilas e hidratos de cálcio (principal produto de cimentos) ambos exibem microestrutura composta por partículas em forma de lamelas. O principal mecanismo responsável pelo fenômeno de fluência macroscópico é frequentemente descrito pelo deslizamento entre as lamelas. O artigo propõe uma abordagem micromecânica para estimar a fluência macroscópica que surge a partir do mecanismo microscópico. A evolução assintótica da fluência para tempos curtos e longos é especialmente investigada. Mais precisamente uma tensão inicial não nula é derivada. Para tempos longos um limiar de porosidade surge da modelagem. Na faixa de porosidades mais baixas a evolução da fluência admite deformação assintótica. Para porosidades altas o problema admite taxa de deformação assintótica

Contracting and Asset Management: Establishing an Asset Specificity Framework for Determining the Optimal Management of Tourism Infrastructure

Infrastructure and engineering asset management strategies are offered to develop the asset base of the tourism industry. This paper explores options for asset management approaches to develop and extend strategic decision-making for infrastructure and engineered assets in the tourism sector

An integrated framework for the design of optimal web banners

Web marketing, Banner design, Internet advertising, Optimization, Statistical analysis, Mixed integer programming,

Hybrid Advertising Auctions

Facebook and Google offer hybrid advertising auctions that allow advertisers to bid on a per-impression or a per-click basis for the same advertising space. This paper studies the properties of equilibrium and considers how to increase efficiency in this new auction format. Rational expectations require the publisher to consider past bid types to prevent revenue losses to strategic advertiser behavior. The equilibrium results contradict publisher statements and suggest that, conditional on setting rational expectations, publishers should consider offering multiple bid types to advertisers. For a special case of the model, we provide a payment scheme that achieves the socially optimal allocation of advertisers to slots and maximizes publisher revenues within the class of socially optimal payment schemes. When this special case does not hold, no payment scheme will always achieve the social optimum.advertising, auctions, Internet marketing, search advertising

An International Perspective of Online Disclosure Presentation: A Comparison of Banner Ad Disclosures from United States, United Kingdom, and Singapore Web Sites

Disclosures, Disclaimers, Banner ads, Internet, Online, Advertising,