Investigation into Shrinkage of High-Performance Concrete Used for Iowa Bridge Decks and Overlays, TR-633, 2013

High-performance concrete (HPC) overlays have been used increasingly as an effective and economical method for bridge decks in Iowa and other states. However, due to its high cementitious material content, HPC often displays high shrinkage cracking potential. This study investigated the shrinkage behavior and cracking potential of the HPC overlay mixes commonly used in Iowa. In the study, 11 HPC overlay mixes were studied. These mixes consisted of three types of cements (Type I, I/II, and IP) and various supplementary cementitious materials (Class C fly ash, slag and metakaolin). Limestone with two different gradations was used as coarse aggregates in 10 mixes and quartzite was used in one mix. Chemical shrinkage of pastes, free drying shrinkage, autogenous shrinkage of mortar and concrete, and restrained ring shrinkage of concrete were monitored over time. Mechanical properties (such as elastic modulus and compressive and splitting tensile strength) of these concrete mixes were measured at different ages. Creep coefficients of these concrete mixes were estimated using the RILEM B3 and NCHRP Report 496 models. Cracking potential of the concrete mixes was assessed based on both ASTM C 1581 and simple stress-to-strength ratio methods. The results indicate that among the 11 mixes studied, three mixes (4, 5, and 6) cracked at the age of 15, 11, and 17 days, respectively. Autogenous shrinkage of the HPC mixes ranges from 150 to 250 microstrain and free dying shrinkage of the concrete ranges from 700 to 1,200 microstrain at 56 days. Different concrete materials (cementitious type and admixtures) and mix proportions (cementitious material content) affect concrete shrinkage in different ways. Not all mixes having a high shrinkage value cracked first. The stresses in the concrete are associated primarily with the concrete shrinkage, elastic modulus, tensile strength, and creep. However, a good relationship is found between cementitious material content and total (autogenous and free drying) shrinkage of concrete.

Surface-dependent strategies and energy flux in benthic marine communities or, why corals do not exist in the Mediterranean

Most structure-building organisms in rocky benthic communities are surface-dependent because their energy inputs depend mainly on the surface they expose to water. Two photosynthetic strategies, divided into calcareous and non calcareous algae, strict suspension-feeders and photosynthetic suspension feeders (e.g. hermatypic corals) are the four main strategies evolutively acquired by benthic organisms. Competition between those strategies occur in relation to productivity of the different species, in such a way that, for given environmental conditions, species with a higher growth (P/B ratio) would dominate. At a worldwide scale, littoral marine benthos can he considered to fit into the four fields defined by two main axes: the first, relates to productivity and relies atrophic and oligotrophic waters and the second is defined by the degree of environmental variability or seasonality (from high to low). Coral reefs (marine ecosystems dominated by photosynthetic suspension feeders) develop in the space of oligotrophic areas with low variability, while kelp beds (marine ecosystem dominated by large, non calcareous algae) are to be found only in eutrophic places with a high variability. The space of eutrophic waters with a low variability do not has specially adapted, high structured, benthic marine ecosystems, and in these conditions opportunistic algae and animals predominate. Finally, photophilic mediterranean benthos -devoid of kelps and without hermatypic corals- typifies the field of oligotrophic areas with high variability; in its more genuine aspect, Mediterranean benthos is represented by small algae with a high percentage of calcareous thallii. In all cases strict suspension-feeders compete successfully with photosynthetic organisms only in situations of low irradiances or very high inputs of POM. In its turn, Mediterranean rocky benthos, in spite of its relative uniformity, is geographically organized along the same axes. The Gulf of Lions and the insular bottoms (Balearic Islands, for example) would correspond to the extremes of eutrophic-high variability areas and oligotrophic-low variability areas, respectively. Irradiance, nutrient and POM concentration, and hydrodynamism are the three variables which mainly affect the distribution of the different surface-dependent strategies, and thus, these parameters are of paramount interest for understanding the trophic structure of Mediterranean benthic communities. In environments non limited by light, nutrient availability, defined as the product between nutrient -POM concentration and hydrodynamism, states the dominance of calcareous versus non calcareous algae. Calcareous algae dominate in oligotrophic waters while non-calcareous algae dominate in moderately eutrophic waters. In light-limited environments, passive suspension feeders (octocorallaria, gorgonians) become dominant species if POM availability is enhanced by a high hydrodynamism (strong currents); in waters with a low charge of POM organisms of other groups, mainly active suspension feeders, predominate (sponges, bryozoans, scleractiniarians). In any case, there always exists a very variable bathymetric zone, depending on light attenuation and nutrient-POM availability, where encrusting calcareous algae strongly compete with suspension feeders (coralligenous).

Production of Asphalt Rubber Concrete by the Dry Process, HR-1062, 1994

Disposal of used tires has been a problem throughout the United States. The 1991 Intermodal Surface Transportation Efficiency Act (ISTEA) requires the use of recycled rubber in asphalt concrete starting in FY94. A moratorium has delayed this requirement until FY95. The Iowa DOT has researched six projects using crumb rubber modifier in asphalt concrete using the wet process. This process involves using a blender-reactor to blend the asphalt cement and crumb rubber. Using the wet process the asphalt cement has to reach a hotter temperature, than is normally required, for reaction to occur. The wet process is also much more expensive than conventional asphalt. This research deals with using a dry process to incorporate crumb rubber into the asphalt concrete mix. The project was constructed by Western Engineering of Harlan, Iowa, on IA 37 between Earling, Iowa and US 59. It was completed in September 1993. Western Engineering used a double drum mixer to produce the crumb rubber modified asphalt concrete by the dry process. The production and construction went well with minor difficulty and the dry process is a less expensive procedure for producing crumb rubber modified asphalt concrete.

Venture capital financing : screening and contracting under assymetric information

Structure of the Thesis This thesis consists of 5 sections. Section 1 starts with the problem definition and the presentation of the objectives of this thesis. Section 2 introduces a presentation of the theoretical foundations of Venture financing and a review of the main theories developed on Venture investing. It includes a taxonomy of contracting clauses relevant in venture contracting, the conflicts they address, and presents some general observations on contractual clauses. Section 3 presents the research findings on the analysis of a European VC's deal flow and investment screening linked to the prevailing market conditions. Section 4 focuses an empirical study of a European VC's investment process, the criteria it uses to make its investments. It presents empirical findings on the investment criteria over time, business cycles, and investment types. It also links these criteria to the VC's subsequent performance. Finally, section 5 presents an empirical research on the comparison of the legal contracts signed between European and United States Venture Capitalists and the companies they finance. This research highlights some of the contracting practices in Europe and the United States.

Issue review : fiscal year 2011 general fund budget projection.

This issue review provides an overall summary of Iowa's general fund budget. This issue review provides projections for the 2010 fiscal year and fiscal year 2011 budgets based on the October 7, 2009 revenue estimating conference's (REC) revenue estimate. The projection also includes the impact of the Governor's 10 percent across-the-board reduction to fiscal year 2010 general fund appropriations, and the Legislative Services Agency's most recent estimates of built-in and anticipated expenditures for fiscal year 2011.

Holism and structural realism

We first introduce structural realism as a position in the metaphysics of science, pointing out the way in which this position replaces intrinsic properties with relations so that it amounts to a holistic in contrast to an atomistic metaphysics. We argue in favour of a moderate version of structural realism that puts objects and relations on the same ontological footing and assess the general philosophical arguments for this position. The second section shows how structural realism gains support from quantum physics. The third section explains how structural realism can be applied to the metaphysics of space-time.

Ultrasound evaluation of synovitis in RA: Correlation with clinical disease activity and sensitivity to change in an observational cohort study.

OBJECTIVE: To evaluate the correlation between clinical measures of disease activity and a ultrasound (US) scoring system for synovitis applied by many different ultrasonographers in a daily routine care setting within the Swiss registry for RA (SCQM) and further to determine the sensitivity to change of this US Score. METHODS: One hundred and eight Swiss rheumatologists were trained in performing the Swiss Sonography in Arthritis and Rheumatism (SONAR) score. US B-mode and Power Doppler (PwD) scores were correlated with DAS28 and compared between the clinical categories in a cross-sectional cohort of patients. In patients with a second US (longitudinal cohort), we investigated if change in US score correlated with change in DAS and evaluated the responsiveness of both methods. RESULTS: In the cross-sectional cohort with 536 patients, correlation between the B-mode score and DAS28 was significant but modest (Pearson coefficient r=0.41, P<0.0001). The same was true for the PwD score (r=0.41, P<0.0001). In the longitudinal cohort with 183 patients we also found a significant correlation between change in B-mode and in PwD score with change in DAS28 (r=0.54, P<0.0001 and r=0.46, P<0.0001, respectively). Both methods of evaluation (DAS and US) showed similar responsiveness according to standardized response mean (SRM). CONCLUSIONS: The SONAR Score is practicable and was applied by many rheumatologists in daily routine care after initial training. It demonstrates significant correlations with the degree of as well as change in disease activity as measured by DAS. On the level of the individual, the US score shows many discrepancies and overlapping results exist.

Holism and structural realism

We first introduce structural realism as a position in the metaphysics of science, pointing out the way in which this position replaces intrinsic properties with relations so that it amounts to a holistic in contrast to an atomistic metaphysics. We argue in favour of a moderate version of structural realism that puts objects and relations on the same ontological footing and assess the general philosophical arguments for this position. The second section shows how structural realism gains support from quantum physics. The third section explains how structural realism can be applied to the metaphysics of space-time.

Design Guide for Improved Quality of Roadway Subgrades and Subbases, TR-525, 2008

The performance of a pavement depends on the quality of its subgrade and subbase layers; these foundational layers play a key role in mitigating the effects of climate and the stresses generated by traffic. Therefore, building a stable subgrade and a properly drained subbase is vital for constructing an effective and long lasting pavement system. This manual has been developed to help Iowa highway engineers improve the design, construction, and testing of a pavement system’s subgrade and subbase layers, thereby extending pavement life. The manual synthesizes current and previous research conducted in Iowa and other states into a practical geotechnical design guide [proposed as Chapter 6 of the Statewide Urban Design and Specifications (SUDAS) Design Manual] and construction specifications (proposed as Section 2010 of the SUDAS Standard Specifications) for subgrades and subbases. Topics covered include the important characteristics of Iowa soils, the key parameters and field properties of optimum foundations, embankment construction, geotechnical treatments, drainage systems, and field testing tools, among others.

Meta-analysis: subclinical thyroid dysfunction and the risk for coronary heart disease and mortality

BACKGROUND: Data on the association between subclinical thyroid dysfunction and coronary heart disease (CHD) and mortality are conflicting. PURPOSE: To summarize prospective evidence about the relationship between subclinical thyroid dysfunction and CHD and mortality. DATA SOURCES: MEDLINE (1950 to January 2008) without language restrictions and reference lists of retrieved articles were searched. STUDY SELECTION: Two reviewers screened and selected cohort studies that measured thyroid function and then followed persons prospectively to assess CHD or mortality. DATA EXTRACTION: By using a standardized protocol and forms, 2 reviewers independently abstracted and assessed studies. DATA SYNTHESIS: Ten of 12 identified studies involved population-based cohorts that included 14 449 participants. All 10 population-based cohort studies examined risks associated with subclinical hypothyroidism (2134 CHD events and 2822 deaths), whereas only 5 examined risks associated with subclinical hyperthyroidism (1392 CHD events and 1993 deaths). In a random-effects model, the relative risk (RR) for subclinical hypothyroidism for CHD was 1.20 (95% CI, 0.97 to 1.49; P for heterogeneity = 0.14; I(2 )= 33.4%). Risk estimates were lower when higher-quality studies were pooled (RR, 1.02 to 1.08) and were higher among participants younger than 65 years (RR, 1.51 [CI, 1.09 to 2.09] for studies with mean participant age <65 years and 1.05 [CI, 0.90 to 1.22] for studies with mean participant age > or =65 years). The RR was 1.18 (CI, 0.98 to 1.42) for cardiovascular mortality and 1.12 (CI, 0.99 to 1.26) for total mortality. For subclinical hyperthyroidism, the RR was 1.21 (CI, 0.88 to 1.68) for CHD, 1.19 (CI, 0.81 to 1.76) for cardiovascular mortality, and 1.12 (CI, 0.89 to 1.42) for total mortality (P for heterogeneity >0.50; I(2 )= 0% for all studies). LIMITATIONS: Individual studies adjusted for different potential confounders, and 1 study provided only unadjusted data. Publication bias or selective reporting of outcomes could not be excluded. CONCLUSION: Subclinical hypothyroidism and hyperthyroidism may be associated with a modest increased risk for CHD and mortality, with lower risk estimates when pooling higher-quality studies and larger CIs for subclinical hyperthyroidism

Análisis de un input de las clases de economía pública: El nivel de cultura fiscal de los alumnos

El objetivo de este artículo es doble. Por un lado, cuantificar el nivel de cultura fiscal de los alumnos de Administración y Dirección de Empresas y de Economía antes de empezar a cursar asignaturas específicas de economía del sector público y de fiscalidad. Y, por otro lado, analizar los posibles factores determinantes de dicho nivel de cultura fiscal. Al tratarse de alumnos de segundo ciclo, éstos ya deberían conocer el funcionamiento de una economía de mercado y el papel que juega el sector público, lo que les debería comportar un mayor interés y una mayor motivación. La idea surgió del convencimiento de los profesores de que saber cuál es el nivel de conocimiento previo sobre cuestiones fiscales que tienen los estudiantes que van a cursar asignaturas de contenido fiscal es un input importante a considerar en el planteamiento de la docencia, puesto que permite mejorar el funcionamiento del curso, motivar el estudio de las asignaturas y mejorar los resultados.

Análisis de un input de las clases de economía pública: El nivel de cultura fiscal de los alumnos

El objetivo de este artículo es doble. Por un lado, cuantificar el nivel de cultura fiscal de los alumnos de Administración y Dirección de Empresas y de Economía antes de empezar a cursar asignaturas específicas de economía del sector público y de fiscalidad. Y, por otro lado, analizar los posibles factores determinantes de dicho nivel de cultura fiscal. Al tratarse de alumnos de segundo ciclo, éstos ya deberían conocer el funcionamiento de una economía de mercado y el papel que juega el sector público, lo que les debería comportar un mayor interés y una mayor motivación. La idea surgió del convencimiento de los profesores de que saber cuál es el nivel de conocimiento previo sobre cuestiones fiscales que tienen los estudiantes que van a cursar asignaturas de contenido fiscal es un input importante a considerar en el planteamiento de la docencia, puesto que permite mejorar el funcionamiento del curso, motivar el estudio de las asignaturas y mejorar los resultados.

Midwest Regional Rail Passenger Initiative and Passenger Rail Service in Iowa status report

This report provides the status of the Passenger Rail Service Revolving Fund and the development and operation of the Midwest regional rail system and the state’s passenger rail service.

Iowa Study of No Passing Zone Signing, 1962

This report is compiled from data gathered by interviewing motorists to sample their opinion of Iowa's method of supplementing the yellow barrier line pavement marking of no passing zones on primary highways with yellow pennant shaped "No Passing Zone" signs mounted on the left shoulder of the highway. The effective designation of no passing zones is one form of control that can contribute to a reduction in the number of fatal high-speed head-on collisions resulting from passing in areas which do not afford sufficient sight distance of approaching traffic. It is the purpose of this report to present an evaluation of the Iowa "No Passing Zone" sign by individuals from all states who have traveled on Iowa's primary highways and who must obey the no passing zone restrictions and be warned by this sign of the presence of the zones. The "No Passing Zone" sign was formulated and approved by the Governor's Safety Committee a short time prior to the experimental erection of the signs. The Governor's Safety Committee adopted this sign as they felt that such a sign should be distinctive (not similar to any other type of sign) and easily visible to a driver attempting a passing maneuver.

Managing FOSS during development: preventive and curative approaches

Today, most software development teams use free and open source software (FOSS) components, because it increases the speed and the quality of the development. Many open source components are the de facto standard of their category. However, FOSS has licensing restrictions, and corporate organizations usually maintain a list of allowed and forbidden licenses. But how do you enforce this policy? How can you make sure that ALL files in your source depot, either belong to you, or fit your licensing policy? A first, preventive approach is to train and increase the awareness of the development team to these licensing issues. Depending on the size of the team, it may be costly but necessary. However, this does not ensure that a single individual will not commit a forbidden icon or library, and jeopardize the legal status of the whole release... if not the company, since software is becoming more and more a critical asset. Another approach is to verify what is included in the source repository, and check whether it belongs to the open-source world. This can be done on-the-fly, whenever a new file is added into the source depot. It can also be part of the release process, as a verification step before publishing the release. In both cases, there are some tools and databases to automate the detection process. We will present the various options regarding FOSS detection, how this process can be integrated in the "software factory", and how the results can be displayed in a usable and efficient way.