An Evaluation and Redesign of a Thermal Compression Evaporator

Evaporators separate liquids from solutions. For maximum efficiency, designers reduce the temperature difference between the heating and heated media using multiple-stage evaporators. This efficiency requires increased size and bulk. A vendor claimed its thermal compression evaporator achieved high efficiency with only two stages. It did not function as claimed. This project investigated the evaporator\u27s design to identify its problems and propose an alternative design with a minimized footprint. The analysis showed theoretical flaws and design weaknesses in the evaporator, including violation of the first law of thermodynamics. An alternative thermal compressor design was created through computational fluid dynamics using spreadsheet methods developed in house, aided by the software product FLUENT. Detailed component sizing was done using the software product HYSYS. The proposed redesign achieved four to one efficiency with two stage thermal compression, using one half of the space of a traditional system of similar performance

Alternative determinism principle for topological analysis of chaos

The topological analysis of chaos based on a knot-theoretic characterization of unstable periodic orbits has proved a powerful method, however knot theory can only be applied to three-dimensional systems. Still, the core principles upon which this approach is built, determinism and continuity, apply in any dimension. We propose an alternative framework in which these principles are enforced on triangulated surfaces rather than curves and show that in dimension three our approach numerically predicts the correct topological entropies for periodic orbits of the horseshoe map.Comment: Accepted for publication as Rapid Communication in Physical Review

Drought-Induced Amplification of Saint Louis encephalitis virus, Florida

We used a dynamic hydrology model to simulate water table depth (WTD) and quantify the relationship between Saint Louis encephalitis virus (SLEV) transmission and hydrologic conditions in Indian River County, Florida, from 1986 through 1991, a period with an SLEV epidemic. Virus transmission followed periods of modeled drought (specifically low WTDs 12 to 17 weeks before virus transmission, followed by a rising of the water table 1 to 2 weeks before virus transmission). Further evidence from collections of Culex nigripalpus (the major mosquito vector of SLEV in Florida) suggests that during extended spring droughts vector mosquitoes and nestling, juvenile, and adult wild birds congregate in selected refuges, facilitating epizootic amplification of SLEV. When the drought ends and habitat availability increases, the SLEV-infected Cx. nigripalpus and wild birds disperse, initiating an SLEV transmission cycle. These findings demonstrate a mechanism by which drought facilitates the amplification of SLEV and its subsequent transmission to humans

The Politics of Katrina in New Orleans: A View From Ground Zero

What is New Orleans like today? What will it take to return the city to some semblance of normalcy? Stunned by the events and revelations of governmental incompetence since Katrina, we review Katrina\u27s aftermath and chime in on current policy debates about the city’s future. Our love for New Orleans may compromise our objectivity, but we find scholarly inspiration in three excellent articles in the last issue of The Forum

Buyer (dis)satisfaction and process innovation: the case of information technology services provision

Studying buyer satisfaction within business services is important because if buyer expectations are not addressed, it can endanger the relationship. Dissatisfied buyers can remain silent or switch supplier without notice, damaging the supplier-buyer relationship. Therefore, suppliers often invest substantial effort in collecting feedback with an expectation that it will foster improvements and innovation in processes. However, using a mixed method sequential research design, we find that there is no direct association between the level of dissatisfaction and process innovation: this poses questions about redundancy of feedback collection. We find that there is a time lag between dissatisfaction identification and problem resolution. We also find that there is a cognitive gap between a supplier’s interpretation of the buyer’s expectations and the buyer’s actual expectations. Further, existing processes that are improved repetitively using discontent feedback suffer from diminishing returns. Suppliers need to proactively seek solutions rather than reactively dealing with buyer problems

Seasonal Forecast of St. Louis Encephalitis Virus Transmission, Florida

Disease transmission forecasts can help minimize human and domestic animal health risks by indicating where disease control and prevention efforts should be focused. For disease systems in which weather-related variables affect pathogen proliferation, dispersal, or transmission, the potential for disease forecasting exists. We present a seasonal forecast of St. Louis encephalitis virus transmission in Indian River County, Florida. We derive an empirical relationship between modeled land surface wetness and levels of SLEV transmission in humans. We then use these data to forecast SLEV transmission with a seasonal lead. Forecast skill is demonstrated, and a real-time seasonal forecast of epidemic SLEV transmission is presented. This study demonstrates how weather and climate forecast skill verification analyses may be applied to test the predictability of an empirical disease forecast model

Relational architecture and relational capability: organisational levers to support strategic supplier relationships

The resource based view of strategy suggests that competitiveness in part derives from a firms ability to collaborate with a subset of its supply network to co-create highly valued products and services. This relational capability relies on a foundational intra and inter-organisational architecture, the manifestation of strategic, people, and process decisions facilitating the interface between the firm and its strategic suppliers. Using covariance-based structural equation modelling we examine the relationships between internal and external features of relational architecture, and their relationship with relational capability and relational quality. This is undertaken on data collected by mail survey. We find significant relationships between both internal and external relational architecture and relational capability and between relational capability and relational quality. Novel constructs for internal and external elements of relational architecture are specified to demonstrate their positive influence on relational capability and relationship quality