26 resultados para Surface termination
Resumo:
This report is a compilation of data on reported terminations of pregnancy in Iowa. These are terminations that actually occurred during the period from January 2000 through December 2000. The annual reporting of termination of pregnancy events is required by state legislation. With this legislative requirement, Iowa joins the other 49 states, the District of Columbia, and New York City in providing information that relates to issues of pregnancy, termination of pregnancy, live births, and fetal deaths (1). This information contributes to the ability of public health officials and policy makers to better understand these issues. The Iowa reporting system is a variation on the model published by the National Center for Health Statistics in 1987 (2). These guidelines described the criteria and expectations for reporting pregnancy information.
Resumo:
Overall, in 2002, annual pregnancy terminations in Iowa increased. In 2002, a total of 7,280 pregnancy terminations were reported in the reporting areas. This represents a 6.4% increase from 2001, when the same reporting areas showed 6,845 pregnancy terminations. Induced terminations of pregnancy increased by 508 cases from 5,722 to 6,230 in 2002, which represents an 8.9% increase. Spontaneous terminations of pregnancy decreased by 75 cases from 1,119 to 1,044, which represents a 6.7% decrease.
Resumo:
The total number of pregnancy terminations decreased from 7,602 in 2000 to 6,845 in 2001. This represents a 10% decrease. Induced termination decreased from 6,059 to 5,722 (a 6% decrease) and spontaneous termination decreased from 1,541 to 1,119 (a 27% decrease). Pregnancy terminations by maternal and child health regions (MCH) • The fertility rate for the state as a whole increased from 62.3 per 1,000 to 62.6 per 1,000, from 2000 to 2001. In 2000, 15 MCH regions had a higher rate than the statewide fertility rate, while in 2001, the number of MCH regions with a higher rate than the statewide fertility rate dropped to 12. Region 7 continued to have the highest fertility rate and region 12 continued to have the lowest rate. • The pregnancy rate decreased from 74.6 per 1,000 to 74.1 per 1,000. Region 16 continued to have the lowest pregnancy rate. However, region 23 had the highest pregnancy rate in 2001, compared to region 7 in 2000. • The induced termination rate decreased 0.6 per 1,000 and down to 9.4 per 1,000 in 2001. Compared to 2000 reports, two fewer regions had a higher rate than the statewide induced termination rate in 2001 (8 regions in 2000 vs. 6 regions in 2001). • The spontaneous termination rate for the state dropped to 1.8 per 1,000 from 2.5 per 1,000. The number of regions with a higher spontaneous termination rate decreased from 9 to 7. Region 14 had the highest rate, and region 20 had the lowest. • The statewide induced termination ratio increased from 145.7 per 1,000 to 149.6 per 1,000. Region 12 had the highest ratio for both years, and region 22 had the lowest ratio. • The statewide spontaneous termination ratio decreased from 39.7 per 1,000 to 29.3 per 1,000. One less region was higher, compared to 2000 data (9 regions in 2000 vs. 8 regions in 2001). In summary, the geographic distribution of the 2001 data showed a pattern similar to that seen in 2000. Generally, the frequency for both induced and spontaneous terminations decreased by month of occurrence, gestational age, marital status, and education level and mother’s age
Resumo:
Six subject areas prompted the broad field of inquiry of this mission-oriented dust control and surface improvement project for unpaved roads: • DUST--Hundreds of thousands of tons of dust are created annually by vehicles on Iowa's 70,000 miles of unpaved roads and streets. Such dust is often regarded as a nuisance by Iowa's highway engineers. • REGULATIONS--Establishment of "fugitive dust" regulations by the Iowa DEQ in 1971 has created debates, conferences, legal opinions, financial responsibilities, and limited compromises regarding "reasonable precaution" and "ordinary travel," both terms being undefined judgment factors. • THE PUBLIC--Increased awareness by the public that regulations regarding dust do in fact exist creates a discord of telephone calls, petitions, and increasing numbers of legal citations. Both engineers and politicians are frustrated into allowing either the courts or regulatory agencies to resolve what is basically a professional engineering responsibility. • COST--Economics seldom appear as a tenet of regulatory strategies, and in the case of "fugitive dust," four-way struggles often occur between the highway professions, political bodies, regulatory agencies, and the general public as to who is responsible, what can be done, how much it will cost, or why it wasn't done yesterday. • CONFUSION--The engineer lacks authority, and guidelines and specifications to design and construct a low-cost surf acing system are nebulous, i.e., construct something between the present crushed stone/gravel surface and a high-type pavement. • SOLUTION--The engineer must demonstrate that dust control and surface improvement may be engineered at a reasonable cost to the public, so that a higher degree of regulatory responsibility can be vested in engineering solutions.
Resumo:
This research project covered a wide range of activities that allowed researchers to understand the relationship between stability, pavement distress, and recycled portland cement concrete (RPCC) subbase aggregate materials. Detailed laboratory and field tests, including pavement distress surveys, were conducted at 26 sites in Iowa. Findings show that specific gravities of RPCC are lower than those of crushed limestone. RPCC aggregate material varies from poorly or well-graded sand to gravel. A modified Micro-Deval test procedure showed that abrasion losses of virgin aggregate materials were within the maximum Micro-Deval abrasion loss of 30% recommended by ASTM D6028-06. Micro-Deval abrasion loss of RPCC aggregate materials, however, was much higher than that of virgin materials and exceeded 30% loss. Modulus of elasticity of RPCC subbase materials is high but variable. RPCC subbase layers normally have low permeability. The pavement surfaces for both virgin and RPCC subbase across Iowa were evaluated to fulfill the objectives of this study related to field evaluation. Visual distress surveys were conducted to gather the detailed current pavement condition information including the type, extent, and severity of the pavement distresses. The historical pavement condition information for the surveyed field sections was extracted from the Iowa DOT's Pavement Management Information System (PMIS). The current surface condition of existing field pavements with RPCC subbase was compared with the virgin aggregate subbase sections using two different approaches. The changes in pavement condition indices (PCI and IRI) with time for both types of pavements (subbases) were compared.
Resumo:
Cities and counties in Iowa have more than 8,890 steel bridges, most of which are painted with red lead paint. The Iowa Department of Transportation (Iowa DOT) maintains less than 35 bridges coated with red lead paint, including seven of the large border bridges over the Mississippi and Missouri Rivers. Because of the federal and state regulations for bridge painting, many governmental agencies have opted not to repaint, or otherwise maintain, lead paint coatings. Consequently, the paint condition on many of these bridges is poor, and some bridges are experiencing severe rusting of structural members. This research project was developed with two objectives: 1) to evaluate the effectiveness of preparing the structural steel surface of a bridge with high pressure water jetting instead of abrasive blasting and 2) to coat the structural steel surface with a moisture-cured polyurethane paint under different surface preparation conditions.
Resumo:
Wet pavement friction is known to be one of the most important roadway safety parameters. In this research, frictional properties of flexible (asphalt) pavements were investigated. As a part of this study, a laboratory device to polish asphalt specimens was refined and a procedure to evaluate mixture frictional properties was proposed. Following this procedure, 46 different Superpave mixtures, one stone matrix asphalt (SMA) mixture and one porous friction course (PFC) mixture were tested. In addition, 23 different asphalt and two concrete field sections were also tested for friction and noise. The results of both field and laboratory measurements were used to develop an International Friction Index (IFI)-based protocol for measurement of the frictional characteristics of asphalt pavements for laboratory friction measurements. Based on the results of the study, it appears the content of high friction aggregate should be 20% or more of the total aggregate blend when used with other, polish susceptible coarse aggregates; the frictional properties increased substantially as the friction aggregate content increased above 20%. Both steel slag and quartzite were found to improve the frictional properties of the blend, though steel slag had a lower polishing rate. In general, mixes containing soft limestone demonstrated lower friction values than comparable mixes with hard limestone or dolomite. Larger nominal maximum aggregate size mixes had better overall frictional performance than smaller sized mixes. In addition, mixes with higher fineness moduli generally had higher macrotexture and friction.
Resumo:
The goals of this project were to implement several stabilization methods for preventing or mitigating freeze-thaw damage to granular surfaced roads and identify the most effective and economical methods for the soil and climate conditions of Iowa. Several methods and technologies identified as potentially suitable for Iowa were selected from an extensive analysis of existing literature provided with Iowa Highway Research Board (IHRB) Project TR-632. Using the selected methods, demonstration sections were constructed in Hamilton County on a heavily traveled two-mile section of granular surfaced road that required frequent maintenance during previous thawing periods. Construction procedures and costs of the demonstration sections were documented, and subsequent maintenance requirements were tabulated through two seasonal freeze-thaw periods. Extensive laboratory and field tests were performed prior to construction, as well as before and after the two seasonal freeze-thaw periods, to monitor the performance of the demonstration sections. A weather station was installed at the project site and temperature sensors were embedded in the subgrade to monitor ground temperatures up to a depth of 5 ft and determine the duration and depths of ground freezing and thawing. An economic analysis was performed using the documented construction and maintenance costs, and the estimated cumulative costs per square yard were projected over a 20-year timeframe to determine break-even periods relative to the cost of continuing current maintenance practices. Overall, the sections with biaxial geogrid or macadam base courses had the best observed freeze-thaw performance in this study. These two stabilization methods have larger initial costs and longer break-even periods than aggregate columns, but counties should also weigh the benefits of improved ride quality and savings that these solutions can provide as excellent foundations for future paving or surface upgrades.
Resumo:
Many transportation agencies maintain grade as an attribute in roadway inventory databases; however, the information is often in an aggregated format. Cross slope is rarely included in large roadway inventories. Accurate methods available to collect grade and cross slope include global positioning systems, traditional surveying, and mobile mapping systems. However, most agencies do not have the resources to utilize these methods to collect grade and cross slope on a large scale. This report discusses the use of LIDAR to extract roadway grade and cross slope for large-scale inventories. Current data collection methods and their advantages and disadvantages are discussed. A pilot study to extract grade and cross slope from a LIDAR data set, including methodology, results, and conclusions, is presented. This report describes the regression methodology used to extract and evaluate the accuracy of grade and cross slope from three dimensional surfaces created from LIDAR data. The use of LIDAR data to extract grade and cross slope on tangent highway segments was evaluated and compared against grade and cross slope collected using an automatic level for 10 test segments along Iowa Highway 1. Grade and cross slope were measured from a surface model created from LIDAR data points collected for the study area. While grade could be estimated to within 1%, study results indicate that cross slope cannot practically be estimated using a LIDAR derived surface model.
Resumo:
Bridge expansion joints, if not properly designed, constructed, and maintained, often lead to the deterioration of critical substructure elements. Strip seal expansion joints consisting of a steel extrusion and neoprene gland are one type of expansion joint and are commonly used by the Iowa Department of Transportation (DOT). Strip seal expansion joints are susceptible to tears and pull outs that allow water, chlorides, and debris to infiltrate the joint, and subsequently the bearings below. One area of the strip seal that is particularly problematic is where it terminates at the interface between the deck and the barrier rail. The Iowa DOT has noted that the initial construction quality of the current strip seal termination detail is not satisfactory, nor ideal, and a need exists for re-evaluation and possibly re-design of this detail. Desirable qualities of a strip seal termination detail provide a seal that is simple and fast to construct, facilitate quick gland removal and installation, and provide a reliable, durable barrier to prevent chloride-contaminated water from reaching the substructure. To meet the objectives of this research project, several strip seal termination details were evaluated in the laboratory. Alternate termination details may not only function better than the current Iowa DOT standard, but are also less complicated to construct, facilitating better quality control. However, uncertainties still exist regarding the long-term effects of using straight-through details, with or without the dogleg, that could not be answered in the laboratory in the short time frame of the research project.
Resumo:
The objectives were to determine the feasibility and performance of this type of construction and to determine if the macadam base is effective in reducin9or eliminating D-cracking deterioration.