Determine Initial Cause for Current Premature Portland Cement Concrete Pavement Deterioration Final Report, 2000

A detailed investigation has been conducted on core samples taken from 17 portland cement concrete pavements located in Iowa. The goal of the investigation was to help to clarify the root cause of the premature deterioration problem that has become evident since the early 1990s. Laboratory experiments were also conducted to evaluate how cement composition, mixing time, and admixtures could have influenced the occurrence of premature deterioration. The cements used in this study were selected in an attempt to cover the main compositional parameters pertinent to the construction industry in Iowa. The hardened air content determinations conducted during this study indicated that the pavements that exhibited premature deterioration often contained poor to marginal entrained-air void systems. In addition, petrographic studies indicated that sometimes the entrained-air void system had been marginal after mixing and placement of the pavement slab, while in other instances a marginal to adequate entrained-air void system had been filled with ettringite. The filling was most probably accelerated because of shrinkage cracking at the surface of the concrete pavements. The results of this study suggest that the durability—more sciecifically, the frost resistance—of the concrete pavements should be less than anticipated during the design stage of the pavements. Construction practices played a significant role in the premature deterioration problem. The pavements that exhibited premature distress also exhibited features that suggested poor mixing and poor control of aggregate grading. Segregation was very common in the cores extracted from the pavements that exhibited premature distress. This suggests that the vibrators on the paver were used to overcome a workability problem. Entrained-air voids formed in concrete mixtures experiencing these types of problems normally tend to be extremely coarse, and hence they can easily be lost during the paving process. This tends to leave the pavement with a low air content and a poor distribution of air voids. All of these features were consistent with a premature stiffening problem that drastically influenced the ability of the contractor to place the concrete mixture. Laboratory studies conducted during this project indicated that most premature stiffening problems can be directly attributed to the portland cement used on the project. The admixtures (class C fly ash and water reducer) tended to have only a minor influence on the premature stiffening problem when they were used at the dosage rates described in this study.

Systematic Identification of High Crash Locations Final Report, 2001

Federal and state policy makers increasingly emphasize the need to reduce highway crash rates. This emphasis is demonstrated in Iowa’s recently released draft Iowa Strategic Highway Safety Plan and by the U.S. Department of Transportation’s placement of “improved transportation safety” at the top of its list of strategic goals. Thus, finding improved methods to enhance highway safety has become a top priority at highway agencies. The objective of this project is to develop tools and procedures by which Iowa engineers can identify potentially hazardous roadway locations and designs, and to demonstrate the utility of these tools by developing candidate lists of high crash locations in the State. An initial task, building an integrated database to facilitate the tools and procedures, is an important product, in and of itself. Accordingly, the Iowa Department of Transportation (Iowa DOT) Geographic Information Management System (GIMS) and Geographic Information System Accident Analysis and Location System (GIS-ALAS) databases were integrated with available digital imagery. (The GIMS database contains roadway characteristics, e.g., lane width, surface and shoulder type, and traffic volume, for all public roadways. GIS-ALAS records include data, e.g., vehicles, drivers, roadway conditions, and the crash severity, for crashes occurring on public roadways during then past 10 years.)

Evaluation of Different Methods to Calculate Heavy-Truck VMT, Final Report, December 2004

Reliable estimates of heavy-truck volumes are important in a number of transportation applications. Estimates of truck volumes are necessary for pavement design and pavement management. Truck volumes are important in traffic safety. The number of trucks on the road also influences roadway capacity and traffic operations. Additionally, heavy vehicles pollute at higher rates than passenger vehicles. Consequently, reliable estimates of heavy-truck vehicle miles traveled (VMT) are important in creating accurate inventories of on-road emissions. This research evaluated three different methods to calculate heavy-truck annual average daily traffic (AADT) which can subsequently be used to estimate vehicle miles traveled (VMT). Traffic data from continuous count stations provided by the Iowa DOT were used to estimate AADT for two different truck groups (single-unit and multi-unit) using the three methods. The first method developed monthly and daily expansion factors for each truck group. The second and third methods created general expansion factors for all vehicles. Accuracy of the three methods was compared using n-fold cross-validation. In n-fold cross-validation, data are split into n partitions, and data from the nth partition are used to validate the remaining data. A comparison of the accuracy of the three methods was made using the estimates of prediction error obtained from cross-validation. The prediction error was determined by averaging the squared error between the estimated AADT and the actual AADT. Overall, the prediction error was the lowest for the method that developed expansion factors separately for the different truck groups for both single- and multi-unit trucks. This indicates that use of expansion factors specific to heavy trucks results in better estimates of AADT, and, subsequently, VMT, than using aggregate expansion factors and applying a percentage of trucks. Monthly, daily, and weekly traffic patterns were also evaluated. Significant variation exists in the temporal and seasonal patterns of heavy trucks as compared to passenger vehicles. This suggests that the use of aggregate expansion factors fails to adequately describe truck travel patterns.

Synthesis of Best Practice for Increasing Protection and Visibility of Highway Maintenance Vehicles, CTRE Final Report Iowa DOT Project TR-475, August 2002

The purpose of this research project is to study current practices in enhancing visibility and protection of highway maintenance vehicles involved in moving operations such as snow removal and shoulder operations, crack sealing, and pothole patching. The results will enable the maintenance staff to adequately assess the applicability and impact of each strategy to their use and budget. The report’s literature review chapter examines the use of maintenance vehicle warning lights, retroreflective tapes, shadow vehicles and truck-mounted attenuators, and advanced vehicle control systems, as well as other practices to improve visibility for both snowplow operators and vehicles. The chapter concludes that the Manual on Uniform Traffic Control Devices does not specify what color or kind of warning lights to use. Thus, a wide variety of lights are being used on maintenance vehicles. The study of the relevant literatures also suggests that there are no clear guidelines for moving work zones at this time. Two types of surveys were conducted to determine current practices to improve visibility and safety in moving work zones across the country and in the state of Iowa. In the first survey of state departments of transportation, most indicated using amber warning lights on their maintenance vehicles. Almost all the responding states indicated using some form of reflective material on their vehicles to make them more visible. Most participating states indicated that the color of their vehicles is orange. Most states indicated using more warning lights on snow removal vehicles than their other maintenance vehicles. All responding state agencies indicated using shadow vehicles and/or truck-mounted attenuators during their moving operations. In the second survey of Iowa counties, most indicated using very similar traffic control and warning devices during their granular road maintenance and snow removal operations. Mounting warning signs and rotating or strobe lights on the rear of maintenance vehicles is common for Iowa counties. The most common warning devices used during the counties’ snow removal operations are reflective tapes, warning flags, strobe lights, and auxiliary headlamps.

Impact of antenna correlation on the capacity of multiantenna channels

This paper applies random matrix theory to obtain analytical characterizations of the capacity of correlated multiantenna channels. The analysis is not restricted to the popular separable correlation model, but rather it embraces a more general representation that subsumesmost of the channel models that have been treated in the literature. For arbitrary signal-to-noise ratios (SNR), the characterization is conducted in the regime of large numbers of antennas. For the low- and high-SNR regions, in turn, we uncover compact capacity expansions that are valid for arbitrary numbers of antennas and that shed insight on how antenna correlation impacts the tradeoffs between power, bandwidth and rate.

High-SNR power offset in multiantenna communication

The analysis of the multiantenna capacity in the high-SNR regime has hitherto focused on the high-SNR slope (or maximum multiplexing gain), which quantifies the multiplicative increase as function of the number of antennas. This traditional characterization is unable to assess the impact of prominent channel features since, for a majority of channels, the slope equals the minimum of the number of transmit and receive antennas. Furthermore, a characterization based solely on the slope captures only the scaling but it has no notion of the power required for a certain capacity. This paper advocates a more refined characterization whereby, as function of SNRjdB, the high-SNR capacity is expanded as an affine function where the impact of channel features such as antenna correlation, unfaded components, etc, resides in the zero-order term or power offset. The power offset, for which we find insightful closed-form expressions, is shown to play a chief role for SNR levels of practical interest.

Revisão integrativa da literatura sobre gestão do regime terapêutico em pacientes com doença pulmonar obstrutiva crônica

Com este estudo pretende-se identificar qual a melhor estratégia de intervenção de enfermagem na promoção da gestão do regime terapêutico em pacientes com Doença Pulmonar Obstrutiva Crônica no ambiente hospitalar. Realizamos uma revisão integrativa da literatura dos anos 2006 a 2009. A partir da análise dos dados, constatamos que os estudos utilizam diferentes elementos e diferentes indicadores de efetividade para avaliarem as estratégias de intervenção utilizadas. Baseando-se nas evidências disponíveis, não é possível identificar qual a melhor estratégia. Desta revisão emerge a definição dos indicadores de resultado mais consensuais na avaliação da efetividade das estratégias de intervenção. Torna-se agora necessário desenvolver, implementar e avaliar a efetividade das estratégias de intervenção de enfermagem, recorrendo a estes indicadores, para definir qual a melhor estratégia de intervenção, baseada na evidência.

Adesão ao tratamento por indivíduos com a co-infecção HIV/tuberculose: revisão integrativa da literatura

Trata-se de revisão integrativa cujo objetivo foi avaliar as evidências disponíveis na literatura sobre os fatores associados à adesão ao tratamento por pacientes com a co-infecção HIV/TB. Foram levantados artigos publicados no período de 2002 a 2008, nas bases de dados LILACS e MEDLINE. O material foi categorizado de acordo com ano de publicação, periódico, local do estudo e fatores relacionados à adesão. A amostra final foi composta por oito artigos. Os fatores encontrados, associados à adesão ao tratamento da co-infecção HIV/TB, relacionam-se: ao indivíduo e ao estilo de vida (tratamento prévio de TB, receio de estigma e discriminação, uso de substâncias químicas, depressão, suporte social), à doença e aos medicamentos (tipo de regime medicamentoso, uso de outros medicamentos, efeitos colaterais, dificuldade de diagnóstico de TB nestes pacientes), e aos serviços de saúde (problemas operacionais para acompanhar o tratamento, treinamento dos profissionais, supervisão, locais distintos para atendimento de TB e de HIV).

Exhaled breath condensate (EBC) as a matrix for nanoparticle exposure and health effect evaluation : final scientific report

The aim of this pilot project was to evaluate the feasibility of assessing the deposited particle dose in the lungs by applying the dynamic light scattering-based methodology in exhaled breath condensateur (EBC). In parallel, we developed and validated two analytical methods allowing the determination of inflammatory (hydrogen peroxide - H2O2) and lipoperoxidation (malondialdehyde - MDA) biomarkers in exhaled breath condensate. Finally, these methods were used to assess the particle dose and consecutive inflammatory effect in healthy nonsmoker subjects exposed to environmental tobacco smoke in controlled situations was done.

Outage thresholds of LDPC codes over nonergodic block-fading channels

This paper derives approximations allowing the estimation of outage probability for standard irregular LDPC codes and full-diversity Root-LDPC codes used over nonergodic block-fading channels. Two separate approaches are discussed: a numerical approximation, obtained by curve fitting, for both code ensembles, and an analytical approximation for Root-LDPC codes, obtained under the assumption that the slope of the iterative threshold curve of a given code ensemble matches the slope of the outage capacity curve in the high-SNR regime.

I-35 Corridor Trade Study - Final Executive Summary, 2005

The Federal Highway Administration (FHWA) and the Departments of Transportation in Texas, Oklahoma, Kansas, Missouri, Iowa and Minnesota combined their efforts to conduct a study of Interstate Highway 35 (I-35) from Laredo, Texas to Duluth, Minnesota. The purpose of the study was to assess the need for improved local, intrastate, interstate, and international service on I-35 and to clearly define a general feasible improvement plan to address those needs

The Generational contract in the family : explaining regime differences in financial transfers from parents to children in Europe

The exchange of social and economic support between the generationsis one of the main pillars of both family life and welfare systems. Thedebate on how to reform the generational contract is still truncated, however, by focusing on its public dimension only, especially on pensions and health care provisions. For a full account, the transfer of resources between adult generations in the family needs to be included as well. In our previous research we have shown that intergenerationalexchange is more likely to take place but less intense in the Nordicwelfare regime than in the Continental and Southern ones. In thepresent paper we analyze the social mechanisms that create and explain this nexus between patterns of intergenerational transfers and welfare regimes. The notion that Southern European family support networksare stronger and more effective than those of Continental and Northern European countries is only partially confirmed. In Southern (and partly in Continental) countries, children are mostly supported by means of co-residence with their parents till their complete economicindependence. However, once they have left the parental home thereare fewer transfers; support tends to be restricted to children who have special needs (such as for the formation of their own family), and depends more on their parents’ resources. In the Nordic countries, in contrast, transfers are less driven by children’s needs and parentalresources.

Evaluation des campagnes de prévention contre le SIDA en Suisse : Les personnels hospitaliers : rapport final 1988

Cette étude est destinée à: 1) évaluer l'impact des messages de prévention chez le personnel hospitalier sous les deux aspects de la vie professionnelle et de la vie privée (connaissance sur les modes de transmission du VIH, représentation et attitudes, comportements, estimation du risque couru de contamination par le VIH dans l'exercice de la profession, attitudes face au dépistage / face à l'information / face au secret médical, etc); 2) décrire les diverses problématiques en relation avec le SIDA chez le personnel hospitalier; 3) évaluer le rôle possible de multiplicateur de messages de prévention de cette population: si ce rôle existe, va-t-il dans le sens d'un renforcement de l'action préventive ou au contraire d'un affaiblissement de cette action par la diffusion de contre-messages ?