991 resultados para Traffic Engineering
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Of the approximately 25,000 bridges in Iowa, 28% are classified as structurally deficient, functionally obsolete, or both. Because many Iowa bridges require repair or replacement with a relatively limited funding base, there is a need to develop new bridge materials that may lead to longer life spans and reduced life-cycle costs. In addition, new and effective methods for determining the condition of structures are needed to identify when the useful life has expired or other maintenance is needed. Due to its unique alloy blend, high-performance steel (HPS) has been shown to have improved weldability, weathering capabilities, and fracture toughness than conventional structural steels. Since the development of HPS in the mid-1990s, numerous bridges using HPS girders have been constructed, and many have been economically built. The East 12th Street Bridge, which replaced a deteriorated box girder bridge, is Iowa’s first bridge constructed using HPS girders. The new structure is a two-span bridge that crosses I-235 in Des Moines, Iowa, providing one lane of traffic in each direction. A remote, continuous, fiber-optic based structural health monitoring (SHM) system for the bridge was developed using off-the-shelf technologies. In the system, sensors strategically located on the bridge collect raw strain data and then transfer the data via wireless communication to a gateway system at a nearby secure facility. The data are integrated and converted to text files before being uploaded automatically to a website that provides live strain data and a live video stream. A data storage/processing system at the Bridge Engineering Center in Ames, Iowa, permanently stores and processes the data files. Several processes are performed to check the overall system’s operation, eliminate temperature effects from the complete strain record, compute the global behavior of the bridge, and count strain cycles at the various sensor locations.
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The Office of Transportation Data, in cooperation with the Federal Highway Administration, prepares this biennial traffic report. This report is used by federal, state, and local governmental agencies in determining highway needs, construction priorities, route location and environmental impact studies, and the application of appropriate design standards. The general public uses this information in determining the amount of traffic that passes a given area as they make their development plans and propose land use changes. The above reflects only a few of the many technical uses for this data.
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College of Engineering at Iowa State University produced a strategic plan for the years 2005-2010.
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OBJECTIVE To describe the scientific knowledge produced about trauma in the elderly caused by traffic accidents in healthcare area studies. METHODS Integrative review of studies from 2003 to 2013 searched in LILACS, SciELO, PubMed and CINHAL databases. We used combination of the descriptors injuries, wounds and accidents, in English, Portuguese and Spanish languages. RESULTS 32 studies were selected. In the thematic analysis, three categories emerged: epidemiological data from traffic accidents involving elderly; traffic accidents with elderly pedestrians; and trauma care in the elderly. We observed increased incidence of trauma in most countries and pedestrians represented a large part of the victims. Among these, the elderly are the most vulnerable group. CONCLUSION Studies showed that trauma care in the elderly need protocols and professionals with training in gerontology specialized in trauma care services.
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Cape Verde, off the coast of Senegal in western Africa, is a volcanic archipelago where soil and water conservation techniques play an important role in the overall subsistence of half a million inhabitants. In fact, the step slopes in the more agricultural islands due to it's volcanic origin, together with semi-arid and arid environments (the country is located in the Sahelian region), characterized by a very irregular wet season, with high intensity rainfall events, make life tough. The hard conditions lead during the first half of the XX century to frequent cycles of drought with severe implications on the local populations, with impressive numbers of deaths by famine, and a decrease of the number of local inhabitants by more than halve in some islands. Maintain the soil in place and the water inside the soil was there after a mater of survival, and the CapeVerdians implemented over the last half century a number of soil and water conservation techniques that cover all the landscape. In this work, we monitored a number of slope soil and water conservation techniques, such as terraces, half moons, live barriers, etc, together with two cultural strategies, used to plant corn and beans on one side and peanuts on the other, with a semi-quantitative methodology, to evaluate their effectiveness. A discussion is given on the costs and effectiveness of the techniques to reduce overland flow production and therefore erosion, and to promote rainfall infiltration.
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Recombinant strains of the oleaginous yeast Yarrowia lipolytica expressing the PHA synthase gene (PhaC) from Pseudomonas aeruginosa in the peroxisome were found able to produce polyhydroxyalkanoates (PHA). PHA production yield, but not the monomer composition, was dependent on POX genotype (POX genes encoding acyl-CoA oxidases) (Haddouche et al. FEMS Yeast Res 10:917-927, 2010). In this study of variants of the Y. lipolytica β-oxidation multifunctional enzyme, with deletions or inactivations of the R-3-hydroxyacyl-CoA dehydrogenase domain, we were able to produce hetero-polymers (functional MFE enzyme) or homo-polymers (with no 3-hydroxyacyl-CoA dehydrogenase activity) of PHA consisting principally of 3-hydroxyacid monomers (>80%) of the same length as the external fatty acid used for growth. The redirection of fatty acid flux towards β-oxidation, by deletion of the neutral lipid synthesis pathway (mutant strain Q4 devoid of the acyltransferases encoded by the LRO1, DGA1, DGA2 and ARE1 genes), in combination with variant expressing only the enoyl-CoA hydratase 2 domain, led to a significant increase in PHA levels, to 7.3% of cell dry weight. Finally, the presence of shorter monomers (up to 20% of the monomers) in a mutant strain lacking the peroxisomal 3-hydroxyacyl-CoA dehydrogenase domain provided evidence for the occurrence of partial mitochondrial β-oxidation in Y. lipolytica.
Validation of the New Mix Design Process for Cold In-Place Rehabilitation Using Foamed Asphalt, 2007
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Asphalt pavement recycling has grown dramatically over the last few years as a viable technology to rehabilitate existing asphalt pavements. Iowa's current Cold In-place Recycling (CIR) practice utilizes a generic recipe specification to define the characteristics of the CIR mixture. As CIR continues to evolve, the desire to place CIR mixture with specific engineering properties requires the use of a mix design process. A new mix design procedure was developed for Cold In-place Recycling using foamed asphalt (CIR-foam) in consideration of its predicted field performance. The new laboratory mix design process was validated against various Reclaimed Asphalt Pavement (RAP) materials to determine its consistency over a wide range of RAP materials available throughout Iowa. The performance tests, which include dynamic modulus test, dynamic creep test and raveling test, were conducted to evaluate the consistency of a new CIR-foam mix design process to ensure reliable mixture performance over a wide range of traffic and climatic conditions. The “lab designed” CIR will allow the pavement designer to take the properties of the CIR into account when determining the overlay thickness.
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We address the problem of scheduling a multiclass $M/M/m$ queue with Bernoulli feedback on $m$ parallel servers to minimize time-average linear holding costs. We analyze the performance of a heuristic priority-index rule, which extends Klimov's optimal solution to the single-server case: servers select preemptively customers with larger Klimov indices. We present closed-form suboptimality bounds (approximate optimality) for Klimov's rule, which imply that its suboptimality gap is uniformly bounded above with respect to (i) external arrival rates, as long as they stay within system capacity;and (ii) the number of servers. It follows that its relativesuboptimality gap vanishes in a heavy-traffic limit, as external arrival rates approach system capacity (heavy-traffic optimality). We obtain simpler expressions for the special no-feedback case, where the heuristic reduces to the classical $c \mu$ rule. Our analysis is based on comparing the expected cost of Klimov's ruleto the value of a strong linear programming (LP) relaxation of the system's region of achievable performance of mean queue lengths. In order to obtain this relaxation, we derive and exploit a new set ofwork decomposition laws for the parallel-server system. We further report on the results of a computational study on the quality of the $c \mu$ rule for parallel scheduling.
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Today, information technology is strategically important to the goals and aspirations of the business enterprises, government and high-level education institutions – university. Universities are facing new challenges with the emerging global economy characterized by the importance of providing faster communication services and improving the productivity and effectiveness of individuals. New challenges such as provides an information network that supports the demands and diversification of university issues. A new network architecture, which is a set of design principles for build a network, is one of the pillar bases. It is the cornerstone that enables the university’s faculty, researchers, students, administrators, and staff to discover, learn, reach out, and serve society. This thesis focuses on the network architecture definitions and fundamental components. Three most important characteristics of high-quality architecture are that: it’s open network architecture; it’s service-oriented characteristics and is an IP network based on packets. There are four important components in the architecture, which are: Services and Network Management, Network Control, Core Switching and Edge Access. The theoretical contribution of this study is a reference model Architecture of University Campus Network that can be followed or adapted to build a robust yet flexible network that respond next generation requirements. The results found are relevant to provide an important complete reference guide to the process of building campus network which nowadays play a very important role. Respectively, the research gives university networks a structured modular model that is reliable, robust and can easily grow.
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Quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety containing traffic safety and related information and news articles
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Quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety containing traffic safety and related information and news articles
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We argue the importance both of developing simple sufficientconditions for the stability of general multiclass queueing networks and also of assessing such conditions under a range of assumptions on the weight of the traffic flowing between service stations. To achieve the former, we review a peak-rate stability condition and extend its range of application and for the latter, we introduce a generalisation of the Lu-Kumar network on which the stability condition may be tested for a range of traffic configurations. The peak-rate condition is close to exact when the between-station traffic is light, but degrades as this traffic increases.
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Report on a special investigation of the Engineering Communications and Marketing Department (ECM) of Iowa State University of Science and Technology for the period January 1, 2003 through December 31, 2007
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We study the impact of university-industry research collaborations on academicoutput, in terms of productivity and direction of research. We report findings froma longitudinal dataset on all the researchers from the engineering departments inthe UK in the last 20 years. We control for the endogeneity caused by the dynamicnature of research and the existence of reverse causality. Our results indicate thatresearchers with industrial links publish significantly more. Productivity, though,is higher for low levels of industry involvement. Moreover, growing ties with theindustry skew research towards a more applied approach.