Flow Number Test and Assessment of AASHTO TP 79-13 Rutting Criteria

The flow number (FN) test was recommended in NCHRP Project 9-19 as a simple performance test for rutting evaluation of asphalt mixtures. The test showed good correlation with rutting performance of mixtures from WesTrack, MnROAD, and FHWA's accelerated loading facility. Despite this fact, no standard protocol was recommended for temperature and required stress level. Subsequent NCHRP studies allowed the development of a provisional standard. AASHTO TP 79-13 includes test parameters for stress and temperature, specimen conditioning, and minimum FN criteria that were established for hot-mix asphalt (HMA) and for warm-mix asphalt (WMA) on the basis of traffic level. In NCHRP Project 9-47A, the rutting potential of WMA mixtures was compared with that of HMA mixtures by using the FN test and the rutting criteria included in the AASHTO TP 79-13 were also evaluated. The analysis included results of samples produced by using field and lab mixtures. Thirteen mixes using 10 WMA technologies and eight corresponding HMA mixes were included. The FN test results for plant-produced WMA mixes were found to be statistically lower than those for corresponding HMA mixes in more than two-thirds of the comparisons. The study also found that the FN criteria recommended for both HMA and WMA seemed appropriate for evaluating plant-produced mixes. Another finding from the study was that FN results from lab-produced WMA mixtures were consistently lower than FN values from field mixtures; this result suggests that adjustments to the specimen conditioning requirements should be considered.

Multilevel Logistic Regression Modeling for Crash Mapping in Metropolitan Areas

The spatial nature of traffic crashes makes crash locations one of the most important and informative attributes of crash databases. It is, however, very likely that crash locations recorded in terms of easting and northing coordinates, distances from junctions, addresses, road names, and types are inaccurately reported. Improving the quality of crash location mapping therefore has the potential to enhance the accuracy of many spatial crash analyses. Determination of correct crash locations usually requires a combination of crash and network attributes with suitable crash-mapping methods. Urban road networks are more sensitive to erroneous matches because of high road density and inherent complexity. A novel crash-mapping method is presented; it is suitable for urban and metropolitan areas and matches all the crashes that occurred in London from 2010 to 2012. The method is based on a hierarchical data structure of crashes (i.e., candidate road links are nested within vehicles and vehicles are nested within crashes) and employs a multilevel logistic regression model to estimate the probability distribution of mapping a crash onto a set of candidate road links. The road link with the highest probability is considered to be the correct segment for mapping the crash. This method is based on two primary variables: (a) distance between the crash location and a candidate segment and (b) difference between the vehicle direction just before the collision and the link direction. Despite the fact that road names were not considered because of the limited availability of this variable in the applied crash database, the developed method provides 97.1% (±1%) accurate matches (N = 1,000). The method was compared with two simpler, nonprobabilistic crash-mapping algorithms, and the results were used to demonstrate the effect of crash location data quality on a crash risk analysis.

Risk and Resilience Analysis for Emergency Projects

A recent review of the FHWA Emergency Relief Program identified the need for standardized procedures to guide states and FHWA when emergency relief projects are developed and reviewed and when eligibility decisions are made. This study builds on the risk analysis and management for critical asset protection approach developed to assess risk for critical infrastructure and reflects the requirements of the FHWA emergency relief program and manual. The approach outlined provides a process for state highway agencies and FHWA division offices to assess the reduced risk and improved resilience of design alternatives as compared with the restore-in-kind design for sites that qualify for emergency relief funds. The process outlined is also applicable to state highway agencies' all-hazards-risk analysis required for their risk-based asset management programs. The extent of damage that occurred from the September 2013 Colorado flood provides a rich environment to test this process and approach. In addition, the Colorado Department of Transportation's desire to provide as much insight as possible to its peer states through this recovery effort provides FHWA with a unique opportunity to develop and refine procedures with full cooperation from a leading state highway agency.

Joint Evacuation and Emergency Traffic Management Model with Consideration of Emergency Response Needs

During and after a disaster, transportation network management is a complex task. In a state of limited serviceability and functionality, surviving transportation infrastructure is expected to act as a vital lifeline and to support different types of operations. This study investigates the joint planning of evacuation operations and emergency traffic management while accounting for emergency response needs. Extended wildfires across a highway network are the assumed disaster setting. Population evacuation takes place by using part of the network, whereas emergency traffic management strategies are applied outside the evacuation zone. Network performance enhancement is pursued through the implementation of lane reversal. The problem is formulated as a two-stage optimization model; minimization of total evacuation time (TET) and minimization of total network travel time (TNTT) are the upper-level objectives for the evacuation area and the rest of the network, respectively. The lower level corresponds to a traffic assignment model on the basis of user equilibrium. Demonstration of the model on a real-world network proves the computational efficiency of the algorithm. The model systematically produces robust results in terms of TET-TNTT minimization and thus addresses the operational needs arising and enhances overall transportation network performance.

USO DE RESÍDUOS DA AGROINDÚSTRIA DE BANANAS NA COMPOSIÇÃO DE SUBSTRATOS PARA PRODUÇÃO DE MUDAS DE PAU PEREIRA

ANÁLISE TEMPORAL DAS VARIAÇÕES DE PARÂMETROS BIOFÍSICOS DA CANA-DE-AÇÚCAR EM JAÍBA-MG

VIABILIDADE DE SEMENTES DE Erythrina velutina Willd PELO TESTE DE TETRAZÓLIO

Caracterização de produtores e consumidores de produtos agroecologicos do município de Ouricuri-PE

O que é Ciência? Concepções de Professores de Ciências e de Estudantes de Licenciatura em Física da Região de Salgueiro-PE Sobre a Natureza da Ciência.

Discute-se, neste trabalho, as compreensões epistemológicas dos professores de ciências das escolas estaduais da região de Salgueiro-PE, assim como de alunos de licenciatura em Física do IF Sertão-PE campus Salgueiro. Foi realizada uma entrevista, com a intenção de avaliar as concepções dos entrevistados acerca da natureza da ciência investigando quais fatores os motivaram a estudar/ensinar física. As entrevistas foram gravadas e posteriormente foi feita uma análise quali-quantitativa dos dados obtidos. Os resultados iniciais mostraram que em geral, os estudantes não queriam estudar física, e que tanto discentes quanto os educadores têm visões inadequadas em relação à natureza da ciência. Ultimamente pesquisas têm indicado que uma compreensão distorcida sobre a natureza da ciência se configura como um obstáculo ao aprendizado sobre ciência. O atual objeto de estudo deste trabalho deve fornecer elementos que indiquem o que os estudantes entendem por ciência e como de se dá a produção do saber científico, possibilitando, a partir de então, propor estratégias que os possibilitem uma visão mais adequada acerca do trabalho cientifico.

Obtenção de um modelo dinâmico do crescimento da bactéria Aeromonas hydrophila a partir de dados isotérmicos

Nos últimos anos, um esforço considerável foi investido no desenvolvimento de modelos matemáticos da dinâmica microbiana em produtos alimentícios. Para que esses modelos possam ser aplicados em alimentos armazenados em condições reais, onde a temperatura varia com o tempo, é necessário considerar o efeito de mudanças em variáveis como temperatura. O objetivo deste trabalho foi obter um modelo dinâmico (não isotérmico) do crescimento da bactéria Aeromonas hydrophila em temperaturas variáveis, a partir de dados isotérmicos das temperaturas 15, 20, 25 e 30°C, ajustados pelo modelo de Gompertz modificado, e avaliar a metodologia proposta por Corradini e Peleg (2005) e Corradini e colaboradores (2006). Os dados do crescimento isotérmicos utilizados foram obtidos no banco de dados ComBase Predictor (Inglaterra). Para construção dos modelos secundários, em função da temperatura, foram utilizadas as funções matemáticas “Power” com auxílio do programa Matlab®, obtendo-se bons ajustes, o que possibilitou na obtenção de um modelo dinâmico e confirmou a metodologia proposta por Corradini e Peleg (2005) e Corradini e colaboradores (2006).