[Voyage en Italie : 1824-1830]. , Palais de la Chancellerie. Détails du Soubassement, au dixième de l'Exec[u]tion : [élévation partielle, profil] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 574

[Voyage en Italie : 1824-1830]. , Palais de la Chancellerie. Détails de l'ordre du premier Etage. au dixième de l'Exec[u]tion : [élévation partielle, profils] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 575

[Voyage en Italie : 1824-1830]. , Palais de la Chancellerie. Détails du Troisième ordre de la façade, au dixième de l'Exec[u]tion : [élévation partielle, profils] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 576

Bridge Deck Expansion Assembly on U.S. 20 in Sioux City, HR-505A, 1990

This project was to determine possible construction problems and evaluate the performance of experimental joint seals. Joints were installed in Woodbury County on US 20 over the Missouri River. ACME-Beta B-520 joints were used. Visual inspections were made yearly. Although the joints performed well for eight years, they deteriorated rapidly and have failed. It was concluded these joints did not perform satisfactorily.

U.S. landowner behavior, land use and land cover changes, and climate change mitigation

Abstract

Examination of Highway Maintenance Garages in the U.S. 30 Corridor between Ames and Cedar Rapids, 1988

A linear programming model is used to optimally assign highway segments to highway maintenance garages using existing facilities. The model is also used to determine possible operational savings or losses associated with four alternatives for expanding, closing and/or relocating some of the garages in a study area. The study area contains 16 highway maintenance garages and 139 highway segments. The study recommends alternative No. 3 (close Tama and Blairstown garages and relocate new garage at Jct. U.S. 30 and Iowa 21) at an annual operational savings of approximately $16,250. These operational savings, however, are only the guidelines for decisionmakers and are subject to the required assumptions of the model used and limitations of the study.

Books, publications, project completion reports, M.S. and Ph. D. theses : research supported by Iowa State Water Resources Research Institute under the Water Resources Research Act of 1964, U.S. Public Law 88-379, U.S. Department of the Interior, Office of Water Resources Research, 1970

This book, published jointly by the American Society of Agronomy, Soil Science Society of American and Iowa State University presents the papers that were given at a symposium held in Ames, Iowa, on Nov. 30 and Dec. 1, 1965 on the general topic of plant environment and efficient water use.

Thin Bonded Concrete Resurfacing U.S. 34 West Burlington, Iowa, HR-34

The Experimental Project was designated as Research Project No. HR-34, sponsored by the Iowa Highway Research Board and constructed by the Iowa Highway Commission. Construction was supervised cooperatively by Engineers of the Iowa Highway Commission and the Portland Cement Association. The objective of the experiment is to study the behavior of relatively thin portland cement concrete resurfacing courses placed with bond on old concrete pavements. The phase of the problem being studied now, involves only pavements in which the old concrete is structurally sound.

The data treatment dependent variability of U-Pb zircon ages obtained using mono-collector, sector field, laser ablation ICP-MS

U-Pb dating of zircons by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) is a widely used analytical technique in Earth Sciences. For U-Pb ages below 1 billion years (1 Ga), Pb-206/U-238 dates are usually used, showing the least bias by external parameters such as the presence of initial lead and its isotopic composition in the analysed mineral. Precision and accuracy of the Pb/U ratio are thus of highest importance in LA-ICPMS geochronology. We consider the evaluation of the statistical distribution of the sweep intensities based on goodness-of-fit tests in order to find a model probability distribution fitting the data to apply an appropriate formulation for the standard deviation. We then discuss three main methods to calculate the Pb/U intensity ratio and its uncertainty in the LA-ICPMS: (1) ratio-of-the-mean intensities method, (2) mean-of-the-intensity-ratios method and (3) intercept method. These methods apply different functions to the same raw intensity vs. time data to calculate the mean Pb/U intensity ratio. Thus, the calculated intensity ratio and its uncertainty depend on the method applied. We demonstrate that the accuracy and, conditionally, the precision of the ratio-of-the-mean intensities method are invariant to the intensity fluctuations and averaging related to the dwell time selection and off-line data transformation (averaging of several sweeps); we present a statistical approach how to calculate the uncertainty of this method for transient signals. We also show that the accuracy of methods (2) and (3) is influenced by the intensity fluctuations and averaging, and the extent of this influence can amount to tens of percentage points; we show that the uncertainty of these methods also depends on how the signal is averaged. Each of the above methods imposes requirements to the instrumentation. The ratio-of-the-mean intensities method is sufficiently accurate provided the laser induced fractionation between the beginning and the end of the signal is kept low and linear. We show, based on a comprehensive series of analyses with different ablation pit sizes, energy densities and repetition rates for a 193 nm ns-ablation system that such a fractionation behaviour requires using a low ablation speed (low energy density and low repetition rate). Overall, we conclude that the ratio-of-the-mean intensities method combined with low sampling rates is the most mathematically accurate among the existing data treatment methods for U-Pb zircon dating by sensitive sector field ICPMS.