Identification of Practices, Design, Construction, and Repair Using Trenchless Technology, TR-570, 2010

Trenchless technologies are methods used for the construction and rehabilitation of underground utility pipes. These methods are growing increasingly popular due to their versatility and their potential to lower project costs. However, the use of trenchless technologies in Iowa and their effects on surrounding soil and nearby structures has not been adequately documented. Surveys of and interviews with professionals working in trenchless-related industries in Iowa were conducted, and the results were analyzed and compared to survey results from the United States as a whole. The surveys focused on method familiarity, pavement distress observed, reliability of trenchless methods, and future improvements. Results indicate that the frequency of pavement distress or other trenchless-related issues are an ongoing problem in the industry. Inadequate soil information and quality control/quality assurance (QC/QA) are partially to blame. Fieldwork involving the observation of trenchless construction projects was undertaken with the purpose of documenting current practices and applications of trenchless technology in the United States and Iowa. Field tests were performed in which push-in pressure cells were used to measure the soil stresses induced by trenchless construction methods. A program of laboratory soil testing was carried out in conjunction with the field testing. Soil testing showed that the installations were made in sandy clay or well-graded sand with silt and gravel. Pipes were installed primarily using horizontal directional drilling with pipe diameters from 3 to 12 inches. Pressure cell monitoring was conducted during the following construction phases: pilot bore, pre-reaming, and combined pipe pulling and reaming. The greatest increase in lateral earth pressure was 5.6 psi and was detected 2.1 feet from the centerline of the bore during a pilot hole operation in sandy lean clay. Measurements from 1.0 to 2.5 psi were common. Comparisons were made between field measurements and analytical and finite element calculation methods.

Meeting of minds : islamic encounters c. 570 to 1750.

Ayuda a los alumnos a entender la mentalidad de las personas que integraban el mundo islámico y de aquellas otras con las que se encontraron en su expansión. Para ello, se estudian las condiciones sociales, políticas, religiosas y culturales del mundo preislámico e islámico hasta 1750. Cada sección se estructura como una investigación histórica, para que cada estudiante seleccione, ordene y clasifique la información y aprenda a relacionar las cuestiones clave. Su contenido se adapta al curriculum nacional inglés.

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 570 - Weiterleitung von Georg Carl Friedrich Kunowski eines Schreibens vom Berliner Kammergericht

2 Blatt

Ms.Ff.F.Stoltze 3. 570 - Brief von Friedrich Stoltze an Friedrich Stoltze und Marie Stoltze

Neujahrs-Glückwünsche

Na 1 Nachlass Max Horkheimer, 570 - Korrespondenzen u.a. mit Margot von Mendelssohn (p. VI 29, 179-317)

208 Briefe zwischen Margot von Mendelssohn und Max Horkheimer; 1 Brief von Max Horkheimer an H. L. Byram, 01.05.1954; 1 Brief an Margot von Mendelssohn von Edgar E. Walden, 16.04.1954; 1 Brief von Robert S. Butts an Margot von Mendelssohn, [1954];

Methane hydrate at DSDP Site 84-570

Deep Sea Drilling Project (DSDP) studies at Site 570 on the landward slope of the Middle America Trench off Guatemala allow for the first time a quantitative estimate of the methane hydrate content in the massive mudstones deposited there. Drilling across the Guatemalan transect on DSDP Legs 67 and 84 has resulted in the greatest number of visual observations of gas hydrate in any marine area. At Site 570, a 1.5-m-long section of massive methane hydrate was unexpectedly cored in an area where none of the usual signs of gas hydrate in seismic records were present. The sediment section is similar to that recovered at the other eight sites off Guatemala, but drilling at Site 570 may have penetrated through a fault zone that provided the space for accumulation of massive gas hydrate. The methane hydrate was analyzed using the following well logs: density, sonic, resistivity, gamma-ray, caliper, neutron porosity, and temperature. The density, sonic, and resistivity logs define a 15-m-thick hydrated zone within which a 4-m-thick nearly pure hydrate section is contained. The methane gas content ranges from 240 m**3 to 1400 m**3 per m**2 of lateral extent; and if the body extends a square kilometer, its total volume of stored gas could be from 240*10**6m**3 to 1400*10**6m**3. Because the acoustic impedance of hydrate calculated from the sonic and density logs shows no anomalous values, the shape and extent of the hydrate body cannot be defined in seismic records. Thus the body is theoretically nonreflective in contrast to the base of the hydrate reflection. The base of the gas hydrate reflection is presumed to be the result of the velocity contrast between sediment containing gas hydrate and sediment containing free gas.