986 resultados para S7-01
Resumo:
The Federal Highway Administration (FHWA) and the Iowa and Illinois Departments of Transportation (Iowa DOT and IDOT) have identified the Selected Alternative for improving Interstate 74 (I-74) from its southern terminus at Avenue of the Cities (23rd Avenue) in Moline, Illinois to its northern terminus one mile north of the I-74 interchange with 53rd Street in Davenport, Iowa. The Selected Alternative identified and discussed in this Record of Decision is the preferred alternative identified in the Final Environmental Impact Statement (FEIS). The purpose of the proposed improvements is to improve capacity, travel reliability, and safety along I-74 between its termini, and provide consistency with local land use planning goals. The need for the proposed improvements to the I-74 corridor is based on a combination of factors related to providing better transportation service and sustaining economic development.
Resumo:
En muchas ocasiones, el conocimiento y la importancia de los grandes yacimientos arqueológicos son dos conceptos diferentes. La adecuación museográfica y las referencias específicas a materiales o intervenciones puntuales pueden enmascarar el valor real de los datos científicos que se conocen sobre ellos, limitando así su importancia dentro del conjunto de la información necesaria para la realización de síntesis y el conocimiento exhaustivo de un período histórico. En muchos casos, se añade la prolongación en el tiempo de excavaciones e intervenciones de consolidación cuyos resultados tardan en ser publicados o bien no llegan nunca a ver la luz, por lo que permanecen en los intrincados vericuetos del circuito científico, quedando como referencias de transmisión personal y provocando innecesarios vacíos en el conocimiento.
Resumo:
Many of the bridges in the state of Iowa have type ‘CF’, ‘EE’, or ‘EF’ expansion joints installed in the bridge approach slabs. These joints, which are typically 4” wide, are currently filled with a foam expansion joint material that is covered with a sealant. Over time the sealant begins to pull off of the walls of the joint and it ultimately fails. The joint, which is now exposed to the weather, is then filled with water and solids. The foam joint material, which is lighter than water, floats out of the joint onto the highway. This foam resembles a large 4” X 6” plank and poses a threat to motorists. A possible solution to this problem would be to replace the foam material with rubber buffings. Rubber buffings are a by-product of the tire retread industry.
Resumo:
The Iowa State Highway Commission purchased a Conrad automatic freeze and thaw machine and placed it in operation during October 1961. There were a few problems, but considering, the many electrical and mechanical devices used in the automatic system it has always functioned quite well. Rapid freezing and thawing of 4"x4"xl8" concrete beams has been conducted primarily in accordance with ASTM C-29l (now ASTM C-666 procedure B) at the rate of one beam per day. Over 4000 beams have been tested since 1961, with determination of the resulting durability factors. Various methods of curing were used and a standard 90 day moist cure was selected. This cure seemed to yield durability factors that correlated very well with ratings of coarse aggregates based on service records. Some concrete beams had been made using the same coarse aggregate and the durability factors compared relatively well with previous tests. Durability factors seemed to yield reasonable results until large variations in durability factors were noted from beams of identical concrete mix proportions in research projects R-234 and R-247. This then presents the question "How reliable is the durability as determined by ASTM C-666?" This question became increasingly more important when a specification requiring a minimum durability factor for P.C. concrete made from coarse aggregates was incorporated into the 1972 Standard Specification for coarse aggregates for concrete.
Resumo:
La Universitat de Vic disposa, entre altres equips, d’una cèl·lula flexible de fabricació, del fabricant Festo, que simula un procés de formació de palets amb els productes que es disposen en un magatzem intermedi. Aquesta cèl·lula està composta de quatre estacions de muntatge diferenciades (càrrega de palets, càrrega de plaques, magatzem intermedi i transport). Cada una disposa d'un PLC SIEMENS S7-300 per la seva automatització, i tots aquests es troben interconnectats amb una xarxa industrial Profibus. L'objectiu d'aquest projecte és implantar el sistema SCADA Vijeo Citect pel control i supervisió de l'estació magatzem d'aquesta cèl·lula flexible de fabricació, establint també un intercanvi de dades entre l'SCADA i el Microsoft Access, per poder ser utilitzat per la docència. Aquest projecte s'ha desenvolupat en cinc fases diferents: 1. La primera fase s'ha dedicat a l'automatització pròpiament de l'estació magatzem a partir de l'autòmat programable Siemens S7-300 i complint amb les necessitats plantejades. 2. En la segona fase s'ha programat i establert la comunicació per l'intercanvi de dades (lectura i escriptura) entre el sistema SCADA Vijeo Citect i la base de dades de Microsoft Access. 3. En la tercera fase s'ha elaborat i programat l'entorn gràfic de supervisió i control del procés a partir del sistema SCADA Vijeo Citect. 4. En la quarta fase s'ha instal·lat un OPC Server en el PC i s'ha establert la comunicació entre el PLC i el sistema SCADA. 5. Finalment s'ha anat revisant i depurant les diferents programacions i comunicacions per tal de que el sistema funcioni com a un conjunt.
Resumo:
With the recent introduction of blended cements, many ready mix producers are using them as their sole source of cement. Iowa DOT specifications currently do not allow blended cements in patching due to their assumed slower strength gain. Patching specifications require opening at 5 hours on 2-lane or 10 hours on 4-lane pavement. This research will investigate early strength of concrete cast with ordinary Type I/II Portland cements and Type I(SM) blended Portland cements.
Resumo:
The Iowa DOT has been using blended cements in ternary mixes since 1999. Use of these supplementary cementitious materials gives concrete with higher strengths and much lower permeability. Use of these materials has been incorporated for use in High Performance Concrete (HPC) decks to achieve lower permeability and thus long term performance. Since we have been using these materials in paving, it would be informative to determine what concrete pavement properties are enhanced as related to high performance concrete. The air void system was excellent at a spacing factor of 0.0047 in (0.120 mm). AVA spacing factor results are much higher than the hardened air void analysis. Although only 3 samples were tested between the image analysis air content and the RapidAir457, there is pretty good agreement between those test methods. Air void analysis indicates that excessive vibration was not required to place the concrete. Vibration was well within the specification limits with an average of 6683 vpm’s with a standard deviation of 461. Overall ride of the project was very good. The average smoothness for the project was 2.1 in/mile (33.8 mm/km). The International Roughness Index (IRI) was 81 in/mi (1.29 m/km). The compressive strength was 6260 psi (43.2 MPa) at 28 days and 6830 (47.1 MPa) at 56 days. The modulus of rupture by third point loading (MOR-TPL) tested at 28 days was 660 psi (4.55 MPa). The AASHTO T277 rapid chloride permeability results at 28 days using the Virginia cure method correlate fairly well with the 56 and 90 day results with standard curing. The Virginia cure method 28 day results were 2475 coulombs and the standard cure 56 and 90 day test results were 2180 and 2118, respectively.
Resumo:
Early deterioration has shown up in a number of Iowa PCC pavements placed between 1986 and 1994. Research has shown that inadequate air content and spacing factors have contributed to the deterioration. Ettringite infilling of air voids is nearly always noted in cores obtained from pavements exhibiting deterioration. This research is to document the early deterioration on I-29 in Pottawattamie county from MP 59 to 72 in both directions.