13 resultados para nonforage fiber source

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


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fiber reinforced polymer (FRP) composite materials are making an entry into the construction market in both buildings and pavements. The application to pavements so far has come in the form of joint reinforcement (dowels and tie bars). FRP resistance to salt corrosion in dowels has made it an alternative to standard epoxy-coated steel dowels for pavements. Iowa State University has completed a large amount of laboratory research to determine the diameter, spacing, and durability of FRP dowels. This report documents the performance of elliptical FRP dowels installed in a field situation. Ten joints were monitored in three consecutive test sections, for each of three dowel spacings (10, 12, and 15 inches) including one instrumented dowel in each test section. The modulus of dowel bar support was determined using falling weight deflectometer (FWD) testing and a loaded crawl truck. FWD testing was also used to determine load transfer efficiency across the joint. The long-term performance and durability of the concrete was also evaluated by monitoring faulting and joint opening measurements and performing visual distress surveys at each joint. This report also contains similar information for standard round, medium elliptical, and heavy elliptical steel dowels in a portion of the same highway. In addition, this report provides a summary of theoretical analysis used to evaluate joint differential deflection for the dowels.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fiber composite materials (FRP) are making an entry into the construction market in both buildings and pavements. The application to pavements comes in the form of joint reinforcement (dowels and tie bars) to date. FRP resistance to salt corrosion in dowels has made it an alternative to standard epoxy coated dowels for pavements. Iowa State University has completed a large amount of laboratory research into the determination of diameter, spacing, and durability of FRP dowels. This report documents the installation of a series of FRP elliptical-shaped dowel joints (including instrumented units) in a field situation and the beginning of a two-year study to compare laboratory results to in-service pavements. Ten joints were constructed for each of three dowel spacings of 10, 12, and 15 inches ( 254, 305, and 381 mm) with one instrumented joint in each test section. The instrumented bars will be load tested with a loaded truck and FWD testing.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Water fact sheet for Iowa Department of Natural Resources and the Geological Bureau.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Monitoring of Iowa's surface waters during the past five years has demonstrated the regular occurrence of fecel bacteria in surface water resources.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Department’s 2007 Greenhouse Gas Inventory is a refinement of previous statewide inventories. It is a bottom-up inventory of two sectors – fossil fuel combustion at federally-recognized major sources of air pollution and fossil fuel combustion and ethanol fermentation at dry mill ethanol plants. This is the first bottomup greenhouse gas inventory conducted for Iowa and the first bottom-up greenhouse gas inventory of ethanol plants in the nation that the Department is aware of. In a bottom-up inventory, facility-specific activity data is used to calculate emissions. In a top-down inventory, aggregate activity data is used to calculate emissions. For example, this bottom-up inventory calculates greenhouse gas emissions from the fossil fuel combustion at each individual facility instead of using the total amount of fossil fuel combusted state-wide, which would be a top-down inventory method. The advantage to a bottom-up inventory is that the calculations are more accurate than a top-down inventory. However, because the two methods differ, the results from a bottom-up inventory are not directly comparable to a top-down inventory.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This research project combined various datasets, existing and created for this project, into an Interactive Mapping Service (IMS) for use by Iowa DOT personnel, county planning and zoning departments and the public in order to make more informed decisions regarding aggregate sources and future access to them. Iowa DOT Technical Advisory Committee meetings were held, along with public forum presentations, in order to understand better the social, ecological and economic limitations to extracting aggregate. The information needed by potential users was conveyed and integrated into a single informational source, the Aggregate Planning IMS.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This brochure describes the textile folk art and needlework of the Hmong tribes who are from Northern China. It is a colorful and exciting addition for American admirers of fine stitching. It also tells of the history of the Hmong tribes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Several primary techniques have been developed through which soil aggregate road material properties may be improved. Such techniques basically involve a mechanism of creating a continuous matrix system of soil and/or aggregate particles, interlocked through the use of some additive such as portland cement, lime, or bituminous products. Details by which soils are stabilized vary greatly, but they are dependent on the type of stabilizing agent and nature of the soil, though the overall approach to stabilization has the common feature that improvement is achieved by some mechanism(s) forcing individual particles to adhere to one another. This process creates a more rigid material, most often capable of resisting the influx of water during freezing, loss of strength due to high moisture content and particle dispersion during thawing, and loss of strength due to migration of fines and/or water by capillarity and pumping. The study reported herein, took a new and relatively different approach to strengthening of soils, i.e., improvement of roadway soils and/or soil-aggregate materials by structural reinforcement with randomly oriented fibers. The purpose of the study was to conduct a laboratory and field investigation into the potential of improving (a) soil-aggregate surfaced and subgrade materials, including those that are frost-prone and/or highly moisture susceptible, and (b) localized base course materials, by uniting such materials through fibrous reinforcement. The envisioned objective of the project was the development of a simple construction technique(s) that could be (a) applied on a selective basis to specific areas having a history of poor performance, or (b) used for improvement of potential base materials prior to surfacing. Little background information on such purpose and objective was available. Though the envisioned process had similarities to fibrous reinforced concrete, and to fibrous reinforced resin composites, the process was devoid of a cementitious binder matrix and thus highly dependent on the cohesive and frictional interlocking processes of a soil and/or aggregate with the fibrous reinforcement; a condition not unlike the introduction of reinforcing bars into a concrete sand/aggregate mixture without benefit of portland cement. Thus the study was also directed to answering some fundamental questions: (1) would the technique work; (2) what type or types of fibers are effective; (3) are workable fibers commercially available; and (4) can such fibers be effectively incorporated with conventional construction equipment, and employed in practical field applications? The approach to obtaining answers to these questions, was guided by the philosophy that an understanding of basic fundamentals was essential to developing a body of engineering knowledge, that would serve as the basis for eventual development of design procedures with fibrous products for the applications previously noted.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This final report to the Iowa Watershed Improvement Review Board by the City of Remsen Utilities consists of accomplishments made by the Remsen Utilities as per this agreement. The City of Remsen Utilities did in fact purchase approximately 27 acres of land lying upstream of the city’s water well field. The land was purchased from Mr. Larry Rodesch and Mr. Rich Harpenau for the purpose of removing nitrates from Remsen’s water source and establishing native prairie grasses to assist in this removal.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Contractors, engineers, owners and manufacturers want to be certain that a new product or procedure will yield beneficial results when compared to the current method of construction. The following research was conducted in order to compare the performance of epoxy coated dowel bars to dowel bars of alternative shapes and materials such as stainless steel and glass fiber reinforced polymer (GFRP). Research was also done on the effect that dowel bar spacing has on the performance of concrete pavements. Four phases of this research are described in this report.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There are a few basic fundamentals you need before starting a source water protection project. These include information on your community’s wells (or intakes), aquifer, source water area, and potential contaminants. All of these essential items should be included in your community’s source water information, you may find this information in the workbook and guidebook.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There are a few basic fundamentals you need before starting a source water protection project. These include information on your community’s wells (or intakes), aquifer, source water area, and potential contaminants. All of these essential items should be included in your community’s source water information, you may find this information in the workbook and guidebook.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The City of Remsen is proactively addressing an increase of nitrates in their public water supply before it becomes a financial catastrophe for them. An intensive assessment was conducted by the Iowa DNR Source Water Protection program as one of four pilot projects in the state. This assessment far surpassed standard desktop assessments and gathered monitoring information in-the-field led by a local watershed group. This was incorporated into a computer modeling program to help the local watershed group discuss alternatives. This comprehensive approach clearly identified the source of nitrate infiltration as a cropland area adjacent to the City well field. Many options were evaluated but only one option provided an economical, viable and secure answer to the water supply needs of Remsen for generations to come. The watershed planning group chose to seek the purchase of this critical area of cropland and convert it to a deep rooted mixture of native grasses. This WIRB funding is intended to be used to acquire a small area totaling 21.1 acres. It represents about 22% of the total local project effort. This will be added to the existing City well field of 40.2 acres and another piece of adjacent property, 35.34 acres, that the City recently acquired as part of an overall aggressive program to protect the community water supply. The City has a signed purchase agreement for 14.4 acres of the 21.1 and a strong verbal commitment to obtain the remaining 5.7 acres. This project has been very active for almost 2 years and is ready to implement immediately upon funding notification. The establishment of native grasses, funded by the local chapter of Pheasants Forever, will take approximately the next three years of operation & maintenance.