Drag and bulk aerodynamic coefficients over shallow water

From direct measurements of the vertical turbulent fluxes of momentum, heat, and water vapor over shallow water, the drag and bulk aerodynamic coefficients are computed and compared with those obtained via the profile technique. The results show thatC _D =C _T =C _E =1.2×10^?3, with variability among their mean values being ? 20 %. All measurements were taken at 8 m above the water surface at Lake Hefner, Oklahoma. The measurement platform was a rectangular tower located within the lake and approximately 1 km from the nearest shore. The depth of the lake at the tower was 8 m.     

A Compatible Single-Phase/Two-Phase Numerical Model: 1. Modeling the Transient Salt-Water/Fresh-Water Interface Motion

Abstract A numerical model (NEWVAR) to simulate the transient movement of a discrete interface between salt water and fresh water has been developed. NEWVAR is designed to allow the analysis of a regional two-dimensional ground-water flow in coastal aquifers. The numerical solution permits the prediction of both regional fresh-water levels and two-dimensional fresh-water/salt-water interface by using nested square meshes.
The numerical solution is based on the finite-difference method; the Gauss-Jordan direct method is used for solving steady- and unsteady-state linear equations. Different procedures are used to avoid numerical difficulties in the transient position of the interface toe for two-dimensional areal flow.
The numerical solution was tested against the analytical ones for the cases of an advancing interface and of a floating fresh-water lens over sea water. These tests showed good agreement, thus verifying the finite-difference approximation. The results of an application of this model to a real aquifer are discussed in a companion paper entitled: "A Compatible Single-Phase/Two-Phase Numerical Model 2. Application to a Coastal Aquifer in Mexico."     

A simple non-linear model for the investigation of the effects of the gap closure at the abutment joints of short bridges

Closure of the gap at the abutment joints of bridges has been the source of extensive damage during the 1971 San Fernando and more recent earthquakes. In this paper a model for the investigation of the effects of this gap closure is presented and analysed. The focus of the model is the representation of the non-linear response of the bridge abutments, the foundation and the columns. The model is used for the investigation of the response of a short bridge located in California.     

Structures and tectonic evolution of the external zone of Alpine Corsica

This paper presents a structural analysis of the external zone of Alpine Corsica, including the autochthonous domain and overlying external nappes (Santa Lucia and Balagne nappes). Two stages of nappe emplacement are identified occurring prior to and after the deposition of the Eocene sediments which were laid down upon first generation thrust contacts but are imbricated with their composite (continental and ophiolitic) basement by second generation thrusts. Five generations of structures with regional extent have been distinguished. However, the first generation has not been recognized within the visible part of the autochthon domain.Eoalpine first generation structures, restricted to allochthonous units, and Late Eocene to Early Oligocene second generation structures were nearly contemporaneous with the two stages of thrusting. The precise significance of E-W third generation structures is poorly understood. Broadly N-S fourth generation structures resulted from Oligocene compressive tectonics (folding and local backthrusting). Finally, fifth generation structures were generated during a Miocene extensional stage.These results are partly consistent with structural features previously reported in the southern and the northern outcrops of the Schistes lustrés, i.e. the main part of the allochthonous domain. A summary of a regional tectonic evolution is thus proposed for Alpine Corsica from Eoalpine obduction to Miocene extension.     

Responding to unmet food needs of displaced persons or refugees:

This paper identifies two types of displaced persons in two different ecological zones in Cameroon as a result of two major causes; a poisonous lake gas explosion in the North West and the effects of a civil war in Chad on Kousseri town in North Cameroon. The displaced persons, through no fault of theirs had to look up to both international and local donor organizations for assistance. This paper addresses the usual unmet food needs, analyses some of the performances that often go wrong but which can be corrected. The paper points out that donor agencies and the host government played major roles in raising food, cash, etc. but regrets to note that unsurmountable logistical problems, improper choice and use of personnel with wider expertise to handle specialized problems, inexistent buffer stocks and non-involvement of the displaced persons in managing some of the problems hindered hard-generated resources from reaching most of the beneficiaries. Better performances lie in reducing dependency on continuous external supplies and also in the local hosts allowing room for small scale agro-pastoral productions which should satisfy and even improve on the unmet nutritional difficiencies and rations of the displaced persons.     

Design charts for a deep circular tunnel under non-uniform loading

Summary This paper describes design charts which can be used to quickly predict the size and shape of the failed rock regions caused by the excavation of a deep tunnel, and the induced closure for cases of non-uniformin-situ stress fields. Through a simple graphical construction, the design charts can also be used to evaluate the performance of a support system.Previously of J. F. T. Agapito and Associates, U.S.A.