An upward drawing of a rooted tree is a drawing such that no parents are below their children. It is ordered if the edges to children appear in prescribed order around each vertex. It is well-known that any tree has an upward (unordered) drawing with width log(n+ 1). For ordered drawings, the best-known bounds for the width for binary trees is O(logn), while for arbitrary trees it is O(2 √ ). W...

Submarine groundwater discharge can significantly influence the near shore transport of chemicals into surface waters. Quantification of the sources and rates of such discharge is critical to development of management strategies. Quantification requires a groundwater seepage meter that provides continuous measurements at high resolutions over an extended period of time. An ultrasonic flow meter...

Most of the hydraulic structures are founded on permeable foundation. There is, however, no procedure to fix the basic barrage parameters, which are depth of sheet piles/cutoffs and the length and thickness of floor, in a cost-effective manner. Changes in hydrological and climatic factors may alter the design seepage head of the hydraulic structures. The variation in seepage head affects the do...

Two types of sabkhas are distinguished in the study coastal area; first type was developed at mouths wadis where sea water enters through high tides; these include; Omm El-Shawesh, Wadi Al-Ain sabkha and Rizk sabkha. A generalized hydrodynamic model for formation this constructed. The second is stretching behind dunes, divided into a longitudinal strip from east to west saline crusts appear som...

An important issue for the performance of underground nuclear waste repositories is the rate of seepage into the waste emplacement drifts. A prediction of this rate is particularly complicated for the potential repository site at Yucca Mountain, Nevada, because it is located in thick, unsaturated, fractured tuff formations. Underground openings in unsaturated media might act as capillary barrie...

Marine hydrocarbon seepage emits oil and gas, including methane ( approximately 30 Tg of CH(4) per year), to the ocean and atmosphere. Sediments from the California margin contain preserved tar, primarily formed through hydrocarbon weathering at the sea surface. We present a record of variation in the abundance of tar in sediments for the past 32,000 years, providing evidence for increases in h...

Amphitheater-headed canyons have been used as diagnostic indicators of erosion by groundwater seepage, which has important implications for landscape evolution on Earth and astrobiology on Mars. Of perhaps any canyon studied, Box Canyon, Idaho, most strongly meets the proposed morphologic criteria for groundwater sapping because it is incised into a basaltic plain with no drainage network upstr...

Lessening the leakage of surface water can reduce the waste of water resources and ground water pollution. To solve the problem that Mengxi River could not store water enduringly, geology investigation, theoretical analysis, experiment research, and numerical simulation analysis were carried out. Firstly, the seepage mathematical model was established based on unsaturated seepage theory; second...

It is difficult to exploit low-permeability reservoirs, and CO2 flooding an effective method improve oil recovery from low permeability reservoirs. However, in the process of flooding, acidic fluids dissolved formation water will react with rock cause dissolution precipitation, resulting pores precipitates, changing evolution law seepage channels, destroying integrity, affecting effect displace...

Methane hydrate is an icelike substance that is stable at high pressure and low temperature in continental margin sediments. Since the discovery of a large number of gas flares at the landward termination of the gas hydrate stability zone off Svalbard, there has been concern that warming bottom waters have started to dissociate large amounts of gas hydrate and that the resulting methane release...