Coupling and comparing a spatially- and temporally-detailed eutrophication model with an ecosystem network model: An initial application to Chesapeake Bay

Coastal waters are modeled for a variety of purposes including eutrophication remediation and fisheries management. Combining these two approaches provides insights which are not available from either approach independently. Coupling is confounded, however, by differences in model formulations and “currencies.” We present here an initial coupling of a spatially- and temporally-detailed eutrophication model, CE-QUAL-ICM, with a network fisheries model, Ecopath. We list commonalities between the models and present algorithms and software for the exchange of information. The models are applied to the central portion of Chesapeake Bay for a contemporary summer period. After comparison of the representations of Chesapeake Bay by the two models, an illustrative example one-way, off-line, coupling is presented. In an initial examination of a 20% increase in predation on phytoplankton by a small, highly-exploited fish (Atlantic menhaden, Brevoortia tyrannus), computed reduction in phytoplankton biomass is accompanied by increased production due to enhanced nutrient recycling. Minimal impact on the structure of the food web or on biomass of higher-trophic level organisms is computed. The algorithms and software can be adapted to alternate eutrophication models and Ecopath applications and provide the first, necessary, steps for subsequent coupling with the time-variable Ecosim model.     

The it Imperative in Business Transformation

The IT imperative is to construct enterprisewide systems and capabilities needed by business to compete. For IS managers, this means embracing the viewpoint that IT plays a crucial role in building the business of the future. IS and business management must act as true partners, each supporting the other in creating an optimally performing company.     

Consideration of the errors inherent in mapping historical glacier positions in Austria from the ground and space (1893-2001)

The historical record of in situ measurements of the terminus positions of the Pasterze and Kleines Fleißkees glaciers in the eastern Alps of Austria is used to assess uncertainties in the measurement of decadal scale changes using satellite data. Topographic maps beginning in 1893, and satellite data from 1976 to 2001, were studied in concert with ground measurements to measure glacier changes. Ground measurements show that the tongue of the Pasterze Glacier receded ∼1150 m from 1893 to 2001, while satellite-derived measurements, using August 2001 Landsat Enhanced Thematic Mapper Plus (ETM+) data registered to an 1893 topographic map, show a recession of 1300-1800 m, with an unknown error. The measurement accuracy depends on the registration technique and the pixel resolution of the sensor when two satellite images are used. When using topographic maps, an additional source of error is the accuracy of the glacier position shown on the map. Between 1976 and 2001, Landsat-derived measurements show a recession of the terminus of the Pasterze Glacier of 479±136 m (at an average rate of 19.1 m a⁻¹) while measurements from the ground showed a recession of 428 m (at an average rate of 17.1 m a⁻¹). Four-meter resolution Ikonos satellite images from 2000 and 2001 reveal a shrinkage of 22,096±46 m² in the Pasterze tongue. The nearby Kleines Fleißkees glacier lost 30% of its area between 1984 and 2001, and the area of exposed ice increased by 0.44±0.0023 km², according to Landsat satellite measurements. As more recent satellite images are utilized, especially data that are geocoded, the uncertainty associated with measuring glacier changes has decreased. It is not possible to assess the uncertainty when an old topographic map and a satellite image are coregistered.     

Enhanced sintering and functional properties of PZT thick films processed using local infrared irradiation

Significantly enhanced functional properties have been observed in lead zirconate titanate thick films when sintered for 1 min using focussed infrared irritation from a halogen bulb. By scanning the heat affected zone similar enhancements in properties were obtained when scan speeds of between 0.06 and 0.16 mm/s were used. Scanning at slower speeds resulted in incomplete sintering while sintering at higher speeds resulted in a degradation of properties. Where enhancements in properties were observed relative permittivity was increased from between 200 and 300 to 600 and 700. Piezoelectric properties (d ₃₃) were observed to increase from 20–30 pC/N to between 60 and 80 pC/N. The enhancement in properties were attributed to the improved densification and grain growth brought about by the high ramp rates and short sintering times achievable using focussed IR irradiation and the ability of the surrounding film to accommodate the sintering strains. Combining multiple scan lines in a rastering pattern failed to yield similar improvements in properties due to effects of stopping and restarting the sintering process in the scan overlap regions and the inability of the film to accommodate the sintering strains across large areas.     

CYPHER MACHINES MAINTENANCE AND RESTORATION SPANNING SIXTY YEARS

We describe the life and times of a servicing mechanic for cypher equipment for the Royal Air Force during World War II and an opportunity to serve again as a cypher machine restorer for Bletchley Park Museum.     

Information technology, operational, and management competencies for supply chain agility: Findings from case studies

Given the growing emphasis on the need for supply chain agility to sustain competitive advantage, this study explores the impact of the relationship between supply chain competence and supply chain agility on firm performance. Although the influence of supply chain agility on firm performance has been acknowledged, this study further articulates the relationship from the perspective of inter-organizational collaboration. We develop a conceptual model based on the resource-based view and employ a multi-case study method in this exploratory research. Our findings highlight the importance of distinguishing the difference between supply chain agility and supply chain competence and their impact on firm performance. This study contributes to the growing body of conceptual and empirical literature on supply chain agility and adds to the understanding of the complexity of supply chain competence.     

66—A COMPARISON OF THREE MODES OF CARPET WEAR

An account is given of the testing of twelve carpets of different constructions in a corridor, on stairs, and by a turning trial. There are differences in ranking by the three modes. None of the rankings correlates very strongly with the results obtained on the Wira Carpet Abrasion Machine or the Tetrapod Walker for this range of tufted and woven carpets.     

Tunable diode laser absorption spectroscopy in coiled hollow optical waveguides

We demonstrate tunable diode laser absorption spectroscopy of CO2 and NH3 near 1.5 microm using a distributed feedback diode laser in conjunction with hollow optical waveguides as long-path sample cells. The waveguides are coiled to reduce the physical extent of the system. The small volume of the waveguide provides rapid instrument response to changes in gas concentration. To reduce the pressure drop associated with long lengths and high flow rates, we perforate the waveguides in a novel geometry providing parallel pneumatic paths while maintaining optical path length. A minimum detectable absorbance of 3.5 x 10(-5) in a 3-m section of waveguide is demonstrated.     

The elastic buckling behaviour of a multi-celled panel under almost pure bending

Observations on the elastic buckling behaviour of a riveted thin-walled three-celled panel under almost pure bending are compared with the output from an efficient finite strip microcomputer program. Results from some preliminary studies using simple channel sections and a box section are also given. The agreement was found to be excellent for the simple sections but only fair for the more complex panel. The possible reasons for this are discussed.