Plant and Laboratory Scale Studies of High Performance Concrete for Bridge Decks in West Virginia

High-performance concrete (HPC) is increasingly used in bridge decks due to its high strength, superior durability and low maintenance resulting in durable and cost effective bridges. FHWA strongly recommended developing suitable HPC mixtures using local material sources and construction technologies for a specific location or state.;As part of a comprehensive R&D program, a field implementation of laboratory developed HPC mixtures was proposed. From a total of eight mixtures developed in the lab with w/cm=0.40, three HPC mixtures were selected using specific local aggregates, in addition to supplementary cementitious materials and chemical admixtures. From these mixtures, three test slabs were produced at a concrete plant in West Virginia, by simulating typical construction practices. The plant-produced slabs were monitored and evaluated for temperature, weather, fresh, hardened, and durability properties for over 90 days from summer to early winter. Maturity-strength relationships were established. Microscopic determination of air-void parameters were conducted using a proposed new method and compared with standard method. Finally, concrete cores were examined by petrography to determine w/cm ratio, compositional variations, and other possible depositions within hardened slabs. The properties of field-mixed match-cured, field-mixed laboratory-cured and laboratory-mixed specimens were compared to check the performance of concrete designed in the laboratory and used in the field.;The results showed that all combinations performed well, with slag + silica fume combinations being the best in terms of compressive strength, resistance to freezing and thawing, and chloride ions penetration. The proposed new method for estimating the air-void parameters was found to be more representative than standard methods. The petrographic examination revealed that aggregates, w/cm ratio, and cementitious materials contents were consistent with the original mixture design. This study will be used to develop guidelines for full-scale demonstration projects for the state of West Virginia

Preparation and decay of a single quantum of vibration at ambient conditions

A single quantum of excitation of a mechanical oscillator is a textbook example of the principles of quantum physics. Mechanical oscillators, despite their pervasive presence in nature and modern technology, do not generically exist in an excited Fock state. In the past few years, careful isolation of GHz-frequency nano-scale oscillators has allowed experimenters to prepare such states at milli-Kelvin temperatures. These developments illustrate the tension between the basic predictions of quantum mechanics that should apply to all mechanical oscillators existing even at ambient conditions, and the complex experiments in extreme conditions required to observe those predictions. We resolve the tension by creating a single Fock state of a vibration mode of a crystal at room temperature using a technique that can be applied to any Raman-active system. After exciting a bulk diamond with a femtosecond laser pulse and detecting a Stokes-shifted photon, the 40~THz Raman-active internal vibrational mode is prepared in the Fock state $|1>$ with $98.5\%$ probability. The vibrational state is read out by a subsequent pulse, which when subjected to a Hanbury-Brown-Twiss intensity correlation measurement reveals the sub-Poisson number statistics of the vibrational mode. By controlling the delay between the two pulses we are able to witness the decay of the vibrational Fock state over its $3.9$ ps lifetime at room temperature. Our technique is agnostic to specific selection rules, and should thus be applicable to any Raman-active medium, opening a new generic approach to the experimental study of quantum effects related to vibrational degrees of freedom in molecules and solid-state systems

Formulación de un plan de negocio para lanzar en el Valle de Aburrá el Tinto de Verano embotellado y enlatado en presentación de 330 ml.

57 páginasEl presente proyecto es un plan de negocios para lanzar en el Valle de Aburrá una nueva bebida alcohólica refrescante llamada tinto de verano, cuyo principal valor agregado es su presentación personal (botella de 330 ml) y un suave sabor en combinación con un alto contenido de alcohol del 7,5% frente al de las cervezas que en promedio es del 4.5%. Este producto está dirigido a un público joven (20 a 35 años) de los estratos socioeconómicos 4, 5 y 6.PregradoIngeniero(a) Administrativo(a

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