Simplified method for the prediction of water activity in binary aqueous solutions

This work describes the application of a simplified method to predict the water activity ( a _w) of binary aqueous solutions in a range of concentrations relevant to intermediate moisture foods. The water activity as a function of molality for several solutes (electrolytes and non-electrolytes) is described by the equation, a _w, = 1 − K m , where K is a constant and m is the molality. Values of K are reported for fifteen non-electrolytes and eight electrolytes. The accuracy of water activity prediction by this method satisfies the actual needs in food research.     

Comportement thermique de differents types d'habitation soumis a un ensoleillement et à une température extérieure périodiques

This paper presents the response of different kinds of schematic dwellings under daily periodic variations of the solar flux and the external temperature. The influence of the parameters which are characteristic of coupled heat transfer is studied (thermal diffusion and heat storage in external and internal walls, heat loses or solar heat supply by windows or airing).Calculations show that for an idealised regulation: (i) The energetical consumption depends only on mean variations of external temperature and solar flux and does not depend on the insulation location. (ii) For a building with a regulated internal temperature, the thermal inertia for the internal walls does not play a role. (iii) For an unregulated building, the internal temperature variations depends of the insulation location. The best location is the external one. (iv) There is an optimal thickness of walls corresponding to the daily periodic variations.     

Industrial and spatial interdependency in modeling: An employment forecasting model for the counties in the San Francisco Bay Region

This paper discusses the structure and empirical estimation of the County Employment Forecasting System (CEFS), a system used to forecast employment for 32 sectors for each one of the nine counties of the San Francisco Bay Region. CEFS differs in several aspects from the majority of models which attempt to simulate employment change at the subregional level; it explicitly considers the relationships between sectors, it accounts for the interactions between counties, and can provide a set of county forecasts which are consistent with the overall regional projections.     

Single-sided ventilation — Part II. further considerations

This paper extends an earlier report of measurements and computer predictions of flows in a cubical cavity exposed on one side to the scavenging effect of an external stream. Further measurements and photographs are presented; they are consistent with each other and with the predictions of the computational model. Specifically, comparisons are made between measured and predicted mean velocities and turbulent shear stresses, and photographs are used to elucidate features of the shear layers generated by accelerating and decelerating external flows. The computer model is used to deduce approximate relations between internal turbulent activity (measured by mean velocity, turbulence energy and shear stress) and external velocity, percentage ‘window’ opening and relative position of the plane walls upstream and downstream of the cavity.     

Integrated modelling under uncertainty in watershed-level assessment and management.

Uncertainty in water quality model predictions is inevitably high due to natural stochasticity, model uncertainty, and parameter uncertainty. An integrated modelling system (modified-BASINS) under uncertainty is described and demonstrated for use in receiving-water quality prediction and watershed management. A Monte Carlo simulation was used to investigate the effect of various uncertainty types on output prediction. Without pollution control measures in the watershed, the concentrations of total nitrogen (T-N) and total phosphorus (T-P) in the Hwaong Reservoir, considering three uncertainty types, would be less than about 4.4 and 0.23 mg L(-1), respectively, in 2012, with 90% confidence. The effects of two watershed management practices, wastewater treatment plants (WWTP) and constructed wetlands (WETLAND), were evaluated. The combined scenario (WWTP + WETLAND) was the most effective at improving reservoir water quality, bringing concentrations of T-N and T-P in the Hwaong Reservoir to less than 3.4 and 0.14 mg L(-1), 24 and 41% improvements, respectively, with 90% confidence. Overall, the Monte Carlo simulation in the integrated modelling system was practical for estimating uncertainty and reliable in water quality prediction. The approach described here may allow decisions to be made based on the probability and level of risk, and its application is recommended.     

Analysis of the effect of polypyrrole synthesis conditions on its capacity to reduce hexavalent chromium

This paper reports the capacity of polypyrrole to reduce toxic hexavalent chromium (Cr(VI)). The influence of using different electrolytes during the polymer's synthesis has been studied. To improve the reduction of Cr(VI), the parameters considered were the polypyrrole morphology and the amount of conducting polymer. Polypyrrole obtained by cyclic voltammetry at a low sweep rate using KBr as supporting electrolyte showed better performance for Cr(VI) reduction compared to coatings obtained by constant potential or cyclic voltammetry at high sweep rates.     

Stable operation range for laser diodes with an integrated passivecavity in the presence of external optical feedback

It is shown that a laser diode with an integrated passive cavity yields higher tolerable levels of feedback from distant reflections than an equivalent long solitary laser diode. To ensure this high tolerance for external feedback, the internal feedback level in the integrated passive cavity must be of the order of about 10%. Then the laser diode remains stable up to external feedback levels in excess of 1% even if the internal reflection phase is not carefully adjusted. External reflections from a cleaved fiber end are then not sufficient to drive the laser into coherence collapse, if realistic coupling efficiencies between laser diode and fiber are taken into account. The low feedback sensitivity is explained by the combination of the long effective length of the laser and a high relaxation resonance frequency. Therefore, quantum-well laser diodes with a long length and a high relaxation resonance frequency are likewise expected to exhibit low feedback sensitivity     

Protein production by Schwanniomyces castellii on starchy substrates, in liquid and solid cultivation

In a preliminary screening, several yeast species were selected among which Endomycopsis fibdigera and Schwunniomyces castellii showed a high yield when inoculated in potato or potato peel media. Both these species were found to have an elevated protein percentage and a good amino acid composition. The effect of some cultural conditions on SCP (single cell protein) production by S. castellii grown on potato medium in a pilot plant 90 1 fermenter was also investigated. Optimal conditions resulted in employing a substrate containing 80 g/l of potatoes, 5.0 8/1 of cornsteep liquor, at 28°C, with a 3% inoculum.
S. castellii and E. fibdigera were also separately inoculated in solid and semi-solid substrates (potatoes, cassava flour, stale bread, maize flour). Under laboratory and semi-pilot plant conditions, carbohydrate conversion into protein was more effective on potato and cassava flour media.