No description available.

A leak-off test is one of the most common procedures to test the fracture pressure of the exposed formations. After cementing and drilling out of the casing shoe, the LOT is run to verify that the casing, cement, and formation can withstand the pressure needed to safely drill the next section of the well. The equivalent mud weight obtained from the test is recorded and reported to government agencies as the strength of the casing shoe. Drilling engineers also rely on the reading from the LOT and use it as the maximum pressure that may be imposed on the formation to avoid fracturing. Exceeding the maximum pressure may result in serious consequences such as lost circulation, one of the most costly events in drilling operations. Therefore, accurate determination of formation fracture gradient is critical and can avoid a variety of well control problems. Considerable efforts to model LOT and leak-off behaviors have been done in the past. Altun (2001) and Paknejad (2007) each presented a unique method to estimate leak-off volume by dividing the pressurized system into four sub-systems: mud compression, casing expansion, fluid leakage, and borehole expansion. The volume response from each sub-system is then combined to represent the total volume pumped during a LOT. However, neither model included the expansion volumes of cement sheath and formation rock outside of the casing; these volumes are not trivial and should not be neglected. In addition, both models use only pump pressure to calculate volumes generated during a LOT. The actual downhole pressure and the pressure acting from the outside are ignored. In this study, the volume contributions from cement sheath expansion and formation rock expansion are calculated using single cylinder Lame’s equation. The results are added with Altun’s borehole expansion volume, mud compression volume, and fluid leakage volume to represent the total volume for the enhanced Altun model. Secondly, a Wider Windows mechanical expansion model is developed based on the concentric cylinder theory. This model simulates the compounded effect of casing, cement, and formation expansion along the cased hole based on pressures inside the wellbore and out in the far-field stress region. The volume generated from concentric cylinder expansion is then combined with Altun’s mud compression volume and fluid leakage volume to simulate the total volume pumped during a LOT. The developed models were verified using three sets of field LOT data obtained from literature and compared with the original Altun model. The results confirmed that leak-off volume along the cased hole should be analyzed as a compounded effect of casing, cement, and formation expansion. Overall, the WW models accurately simulate both leak-off volume and leak-off behaviors. / text

by Siu Wai-man, Raymond. / Bibliography: leaves 75-76 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1986

In this paper we study sensitivity analysis of the uncapacitated single level economic lot-sizing problem, which was introduced by Wagner and Whitin about thirty years ago. In particular we are concerned with the computation of the maximal ranges in which the numerical problem parameters may vary individually, such that a solution already obtained remains optimal. Only recently it was discovered that faster algorithms than the Wagner-Whitin algorithm exist to solve the economic lot-sizing problem. Moreover, these algorithms reveal that the problem has more structure than was recognized so far. When performing the sensitivity analysis we exploit these newly obtained insights.

No description available.

No description available.

The main goal of this practicum is to explore the issues of ecosystem services associated with a commercial parking lot in a temperate climatic condition. The site chosen was in Sydney, Australia. The intention of the design is to examine how ecosystem services can be engaged to reduce carbon emission; improve air and water quality; reduce stormwater runoff; mitigate temperature fluctuations; increase biodiversity and enhance human comfort and delight.

Marburg, Universiẗat, Diss., 2000.

Parking lots can no longer be the inhospitable, pedestrian-minimalizing, environmentally-degrading uses of valuable open space that are accepted and tolerated as the "norm". The open space that makes way for parking lots is too precious to be wasted on places that provide little or no comfort to the user while also contributing to the degradation of the environment. By inserting a fantastical landscape — one which engages the senses through color, texture, and smell — into the mind-dulling landscape of a large surface parking lot, the resulting comparison is a waking call about the missed opportunities of celebrating beauty and the environment. This gives value to the landscape in today's mobile society where the natural world appears to be losing ground to the automobile. This thesis proposes a series of landscape structures over a vast surface parking lot — Potomac Yard Shopping Center in Alexandria, Virginia — that provide open space,the ecological benefits of absorbing storm water runoff and preventing UV bounce back, while ultimately repositioning and rejoining the pedestrian with the landscape. The project does not set out to eradicate parking. Rather, the project recognizes the need for parking in today's mobile society but prioritizes the important connection that must exist between people and nature within that context. / Master of Landscape Architecture

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.