12 resultados para Reducing habitats

em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States


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The Attorney General’s Consumer Protection Division receives hundreds of calls and consumer complaints every year. Follow these tips to avoid unexpected expense and disappointments. This record is about: Tips for Reducing Gasoline Use

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The Attorney General’s Consumer Protection Division receives hundreds of calls and consumer complaints every year. Follow these tips to avoid unexpected expense and disappointments. This record is about: Tips for Reducing Gasoline Use

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Prescription drug abuse is the nation’s fastest-growing drug problem, as outlined by the White House Office of National Drug Control Policy’s 2011 national plan “Responding to America’s Prescription Drug Abuse Crisis.” The urgency of the challenge is underscored in other reports, including a recent analysis by the Centers for Disease Control (CDC) that said: “Overdoses involving prescription painkillers are at epidemic levels and now kill more Americans than heroin and cocaine combined.” According to the CDC, more than 40 people die in America every day from overdoses involving narcotic pain relievers such as hydrocodone (Vicodin), oxycodone (Oxycontin), methadone and oxymorphone (Opana). In Iowa, the situation is similar, at least in some ways. Prescription drug abuse is one of the fastest-growing forms of substance abuse in our state too, though its scope is smaller and on a more manageable scale when compared with most other states. The Iowa Department of Public Health, Bureau of Vital Statistics, reports the drug overdose deaths of at least 130 Iowans over the last three years (2008-2010) due to non-heroin opioids (i.e., prescription pain relievers such as oxycodone, hydrocodone and methadone), nearly as many as for the previous eight years combined (149 from 2000-2007).

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Sign vandalism has traditionally been a vexing problem for Iowa counties. The extent of the cost and incidence of these acts have never been fully ascertained, but a 1990 survey indicated that they cost Iowa counties more than 1.5 million dollars annually. In 1990, the Iowa Legislature recognized the seriousness of the problem and strengthened the existing sign vandalism law by increasing the penalty for illegal possession of a traffic control device from a simple to a serious misdemeanor. However, the courts must be willing to prosecute vandals to the magnitude provided in the Iowa Code. An educational campaign begun in 1987 involving over 200 Iowa school districts to educate students on the seriousness of the problem evidently did not have the effect of dramatically reducing the overall cost of sign vandalism in Iowa. This study sought to define the scope of the problem and possibly offer some effective countermeasures to combat sign vandalism and theft in Iowa.

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This Executive Summary presents a brief summary of the main research report, "The Economics of Reducing the County Road System: Three Case Studies in Iowa" (DOT/OST/P-34/86-035). The case studies are described, as well as the analytic methodology and research findings.

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This research project looked at the economic benefits and costs associated with alternative strategies for abandoning low volume rural highways and bridges. Three test counties in Iowa were studied, each 100 square miles in size: Hamilton County having a high agricultural tax base and a high percentage of paved roads and few bridges; Shelby County having a relatively low agricultural tax base, hilly terrain and a low percentage of paved road and many bridges; and Linn County having a high agricultural tax base, a high percentage of paved roads and a large number of non-farm households. A questionnaire survey was undertaken to develop estimates of farm and household travel patterns. Benefits and costs associated with the abandonment of various segments of rural highway and bridge mileages in each county were calculated. "Benefits" calculated were reduced future reconstruction and maintenance costs, whereas "costs" were the added cost of travel resulting from the reduced mileage. Some of the findings suggest limited cost savings from abandonment of county roads with no property access in areas with large non-farm rural population; relatively high cost savings from the abandonment of roads with no property access in areas with small rural population; and the largest savings from the conversion of public dead-end gravel roads with property or residence accesses to private drives.

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The Iowa Department of Transportation (DOT) is continually improving the pavement management program and striving to reduce maintenance needs. Through a 1979 pavement management study, the Iowa DOT became a participant in a five state Federal Highway Administration (FHWA) study of "Transverse Cracking of Asphalt Pavements". There were numerous conclusions and recommendations but no agreement as to the major factors contributing to transverse cracking or methods of preventing or reducing the occurrence of transverse cracking. The project did focus attention on the problem and generated ideas for research. This project is one of two state funded research projects that were a direct result of the FHWA project. Iowa DOT personnel had been monitoring temperature susceptibility of asphalt cements by the Norman McLeod Modified Penetration Index. Even though there are many variables from one asphalt mix to another, the trend seemed to indicate that the frequency of transverse cracking was highly dependent on the temperature susceptibility. Research project HR-217 "Reducing the Adverse Effects of Transverse Cracking" was initiated to verify the concept. A final report has been published after a four-year evaluation. The crack frequency with the high temperature susceptible asphalt cement was substantially greater than for the low temperature susceptible asphalt cement. An increased asphalt cement content in the asphalt treated base also reduced the crack frequency. This research on prevention of transverse cracking with fabric supports the following conclusions: 1. Engineering fabric does not prevent transverse cracking of asphalt cement concrete. 2. Engineering fabric may retard the occurrence of transverse cracking. 3. Engineering fabric does not contribute significantly to the structural capability of an asphalt concrete pavement.

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This research was initiated to identify methods of reducing the occurrence of transverse cracking. Eight (four repetitive) research sections were established to study three variations in the asphalt concrete pavement. The first variation was the comparison of low- and high-temperature-susceptible asphalt cement (AC) from two different sources. The second variable was to saw and seal transverse joints at spacings varying from 40 to 100 ft. The third variable was to increase the AC content in the asphalt treated base by 1 percent. The research sections were constructed with relatively few problems. Crack and joint surveys have been conducted on all research sections at intervals of less than 1 year since construction. No cracking was identified after the first winter season. The sawed joints also remained sealed through the first winter. At an age of approximately 1 1/2 years there was substantial cracking of the high-temperature-susceptible AC sections and substantial failure of the sealant material in the sawed joints. After almost 4 years, the asphalt pavement constructed with the high-temperature-susceptible AC produced a crack interval of 35 ft, the low-temperature-susceptible AC yielded an interval of 170 ft, and the low-temperature-susceptible AC with an increased AC content yielded an interval of 528 ft. The Pen-Vis number is an effective measure of temperature susceptibility of asphalt cements. The frequency of transverse cracking is affected by the temperature susceptibility of the AC. An increased AC content also reduces the frequency of transverse cracking.

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Atterberg limits tests were performed on mixtures of gumbotil soil and the various chief chemical compounds found in hydrated limes. The results were then checked with commercial hydrated limes of varying chemical compositions. Results indicate that among the major constituents of hydrated limes Ca(OH)2 is most effective in reducing soil plasticity. MgO shows a moderate effect, but Mg(OH)2 and CaCO3 show practically no effect. There is, however, practically no difference between different types or between the same type of commercial hydrated limes for the reduction of soil plasticity. The choice of lime for soil-lime stabilization should, therefore, be dictated by the relative price and pozzolanic strength characteristics of the lime.

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The objective of this research project was to identify a method of reducing the adverse effect of transverse cracking and to improve the performance of asphalt pavement. The research involved three variations from the contractor's planned operation. Briefly, they were: (1) use of another asphalt cement; (2) saw and seal transverse joints; and (3) increased asphalt cement content. The following conclusions were reached: (1) an improved sealant or sealing procedure is needed if transverse joints are to be used in asphalt pavements; (2) the penetration-viscosity number (PVN) is an effective measure of the temperature susceptibility of asphalt cements; (3) the use of a high temperature susceptible asphalt cement produced severe transverse cracking; (4) the use of asphalt cements with low temperature susceptibility will reduce the frequency of transverse cracking; and (5) an increased asphalt cement content in the asphalt treated base will reduce the frequency of transverse cracking.

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Concrete durability may be considered as the ability to maintain serviceability over the design life without significant deterioration, and is generally a direct function of the mixture permeability. Therefore, reducing permeability will improve the potential durability of a given mixture and, in turn, improve the serviceability and longevity of the structure. Given the importance of this property, engineers often look for methods that can decrease permeability. One approach is to add chemical compounds known as integral waterproofing admixtures or permeability-reducing admixtures, which help fill and block capillary pores in the paste. Currently, there are no standard approaches to evaluate the effectiveness of permeability-reducing admixtures or to compare different products in the US. A review of manufacturers’ data sheets shows that a wide range of test methods have been used, and rarely are the same tests used on more than one product. This study investigated the fresh and hardened properties of mixtures containing commercially available hydrophilic and hydrophobic types of permeability-reducing admixtures. The aim was to develop a standard test protocol that would help owners, engineers, and specifiers compare different products and to evaluate their effects on concrete mixtures that may be exposed to hydrostatic or non-hydrostatic pressure. In this experimental program, 11 concrete mixtures were prepared with a fixed water-to-cement ratio and cement content. One plain mixture was prepared as a reference, 5 mixtures were prepared using the recommended dosage of the different permeability-reducing admixtures, and 5 mixtures were prepared using double the recommended dosage. Slump, air content, setting time, compressive and flexural strength, shrinkage, and durability indicating tests including electrical resistivity, rapid chloride penetration, air permeability, permeable voids, and sorptivity tests were conducted at various ages. The data are presented and recommendations for a testing protocol are provided.

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Effective winter maintenance makes use of freezing-point-depressant chemicals (also known as ice-control products) to prevent the formation of the bond between snow and ice and the highway pavement. In performing such winter maintenance, the selection of appropriate ice-control products for the bond prevention task involves consideration of a number of factors, as indicated in Nixon and Williams (2001). The factors are in essence performance measurements of the ice-control products, and as such can be easily incorporated into a specification document to allow for selection of the best ice-control products for a given agency to use in its winter maintenance activities. Once performance measures for de-icing or anti-icing chemicals have been specified, this allows the creation of a quality control program for the acceptance of those chemicals. This study presents a series of performance measurement tests for ice-control products, and discusses the role that they can play in such a quality control program. Some tests are simple and rapid enough that they can be performed on every load of icecontrol products received, while for others, a sampling technique must be used. An appropriate sampling technique is presented. Further, each test is categorized as to whether it should be applied to every load of ice-control products or on a sampling basis. The study includes a detailed literature review that considers the performance of ice-control products in three areas: temperature related performance, product consistency, and negative side effects. The negative side effects are further broken down into three areas, namely operational side effects (such as chemical slipperiness), environmental side effects, and infrastructural side effects (such as corrosion of vehicles and damage to concrete). The review indicated that in the area of side effects the field performance of ice-control products is currently so difficult to model in the laboratory that no particular specification tests can be recommended at this time. A study of the impact of ice-control products on concrete was performed by Professor Wang of Iowa State University as a sub-contract to this study, and has been presented to the Iowa Highway Research Board prior to this report.