Bacterial abundance, population dynamics and related environmental parameters were determined in bal last water during a transPacific voyage from Japan to the west coast of Canada. Water samples were collected from four ballast tanks, two of which underwent mid-ocean exchange (MOE) and two that remained unexchanged (control). Bacterial abundances in the unexchanged tanks increased from ~6.4×10 ...

The greater Wellington region, New Zealand, is highly vulnerable to large earthquakes because it is cut by active faults. Bulk water supply pipelines cross the Wellington Fault at several different locations, and there is considerable concern about severe disruption of the provision of reticulated water supplies to households and businesses in the aftermath of a large earthquake. A number of po...

A model of the concentrations of suspended solids (SS) in the aeration tanks and in the effluent from these during Aeration tank settling (ATS) operation is established. The model is based on simple SS mass balances, a model of the sludge settling and a simple model of how the SS concentration in the effluent from the aeration tanks depends on the actual concentrations in the tanks and the slud...

Onsite sanitation with septic tanks is popular in most of the Asian countries. The case study conducted in Hanoi and suburban area of Bangkok indicates that the septic tanks employed did not perform as required. The septic tanks just convert the suspended pollutants into dissolved form and release them to the environment due to insufficient maintenance. Thus the effluent from the septic tank is...

In seismic interpretation with fluid flow simulation, we construct simple reservoir models with a small number of flow units, such as geologic layers and fault blocks. We call these units tanks and connect them with tubes. For such simple models, we may interactively adjust reservoir properties, such as porosities of tanks and transmissibilities of tubes. Numerical experiments suggest that para...

Initial results of an investigation towards finding an efficient non-cylindrical fuselage configuration for a conceptual blended-wing-body flight vehicle were presented. A simplified 2-D beam column analysis and optimization was performed first. Then a set of detailed finite element models of deep sandwich panel and ribbed shell construction concepts were analyzed and optimized. Generally these...

Suppose that water towers like those shown in Figure 1 are initially filled with water and have the same volume, height, and cross-sectional outlet area. Which one empties first? This problem arises naturally when designing watersupplying tanks or funnels. We find a formula expressing the emptying time as a function of the volume of liquid and its initial height. We compute the emptying time fo...

Rainwater harvesting (RWH) is a relatively inexpensive technology that has the potential to provide safe water in communities where conventional technologies are difficult to implement. In this study, the microbiological quality of rainwater harvested from rooftops and ground-surface runoff was evaluated based on the concentrations of Escherichia coli, total coliforms and enterococci. Samples w...