National geodatabase of tidal stream power resource in USA

A geodatabase of tidal constituents is developed to present the regional assessment of tidal stream power resource in the USA. Tidal currents are numerically modeled with the Regional Ocean Modeling System (ROMS) and calibrated with the available measurements of tidal current speeds and water level surfaces. The performance of the numerical model in predicting the tidal currents and water levels is assessed by an independent validation. The geodatabase is published on a public domain via a spatial database engine with interactive tools to select, query and download the data. Regions with the maximum average kinetic power density exceeding 500 W/m² (corresponding to a current speed of ～1 m/s), total surface area larger than 0.5 km² and depth greater than 5 m are defined as hotspots and documented. The regional assessment indicates that the state of Alaska (AK) has the largest number of locations with considerably high kinetic power density, followed by, Maine (ME), Washington (WA), Oregon (OR), California (CA), New Hampshire (NH), Massachusetts (MA), New York (NY), New Jersey (NJ), North and South Carolina (NC, SC), Georgia (GA), and Florida (FL).     

Sugar replacement in sweetened bakery goods

This review presents the state‐of‐the‐art concerning the application of natural and artificial high‐intensity sweeteners, fructans and bulking agents such as polyols as sugar replacers in sweet‐baked goods and their effects on product characteristics. The recent much publicised attention given to weight gain of the population and its consequences on the occurrence of diet‐related diseases in developed countries has influenced the food manufacturers attempts to provide the consumer with reduced energy products. The replacement of sucrose in sweet bakery products by alternative natural or artificial sweeteners can be a challenging issue. Sucrose as a main ingredient in sweet bakery products contributes, aside from providing sweetness, to numerous processing and product characteristics. Intense sweeteners have a high sweetness compared with sucrose but lack in their contribution to the body of the product, whereas the replacement of sucrose with bulking sweeteners may result in products with a similar body but a lack in taste and flavour.     

Domestic exposure to fungal allergenic particles determined by halogen immunoassay using subject's serum versus particles carrying three non‐fungal allergens determined by allergen‐specific HIA

Studies that estimate indoor aeroallergen exposure typically measure a pre‐selected limited range of allergens. In this study, inhalable aeroallergen particles were quantified using the halogen immunoassay (HIA) to determine the contribution of fungal and non‐fungal aeroallergens to total allergen exposure. Bioaerosols from 39 homes of fungal‐allergic subjects were sampled using inhalable fraction samplers and immunostained by HIA using resident subject's immunoglobulin E (IgE) to detect allergen‐laden particles. Fungal aerosols as well as particles carrying mite, cat, and cockroach allergens were identified and enumerated by HIA. Reservoir dust‐mite (Der p 1), cat (Fel d 1), and cockroach (Bla g 1) allergen concentrations were quantified by ELISA. Fungal particles that bound subject's IgE in the HIA were 1.7 (bedroom)‐ and 1.4 (living room)‐fold more concentrated than Der p 1, Fel d 1, and Bla g 1 allergen particles combined. Predominant fungal conidia that bound IgE were derived from common environmental genera including Cladosporium and other fungi that produce amerospores. Airborne mite, cat, and cockroach allergen particle counts were not associated with reservoir concentrations determined by ELISA. This study demonstrates that inhalable fungal aerosols are the predominant aeroallergen sources in Sydney homes and should be considered in future exposure assessments.     

Photo-Induced Surface Charge Density Effects In Dye-Sensitized Zinc Oxide***

Measurements of surface potential and surface conductivity in zinc oxide thin films in contact with eosin dye show that two regimes of spectral sensitization are involved under vacuum conditions. The dye molecules at the interface trap conduction electrons in the dark at a site close in energy to the dye ground state leading to a Schottky barrier. The return of the trapped electrons from the excited dye is held responsible for “thin layer” sensitization. With “thick” dye layers an additional contribution arises from charge transfer between the photoconducting solid dye and the zinc oxide substrate, in a direction which tends to equilibrate the Fermi levels in the two media, The decay of the ”thick layer” sensitized photoeffect is identical to the decay of the field effect in undyed zinc oxide films and is controlled by zinc oxide surface states.     

Energy efficiency and renewables policies: Promoting efficiency or facilitating monopsony?

The cliché in the electricity sector, the “cheapest power plant is the one we don’t build,” neglects the benefits of the energy that plant would generate. That economy-wide perspective need not apply in considering benefits to only consumers if not building that plant was the exercise of monopsony power. A regulator maximizing consumer welfare may need to avoid rationing demand at monopsony prices. Subsidizing energy efficiency to reduce electricity demand at the margin can solve that problem, if energy efficiency and electricity use are substitutes. Renewable energy subsidies, percentage use standards, or feed in tariffs may also serve monopsony as well with sufficient inelasticity in fossil fuel electricity supply. We may not observe these effects if the regulator can set price as well as quantity, lacks buyer-side market power, or is legally precluded from denying generators a reasonable return on capital. Nevertheless, the possibility of monopsony remains significant in light of the debate as to whether antitrust enforcement should maximize consumer welfare or total welfare.     

Charaterization of UHMWPE fiber/matrix adhesion by dynamic mechanical spectrometry

The tensile and dynamic mechanical properties of polystyrene and a poly(styrene-co-buty1 acrylate-co-cyclohexy1 methacrylate) statistical terpolymer (terpolymer) reinforced by randomly oriented, discontinuous ultra-high molecular weight polyethylene (UHMWPE) fibers are presented in terms of the fiber/matrix interfacial properties. Using a thermomechanical block model based on the parallel rule of mixtures, the adhesion characteristics of poly(butyl acrylate) (PBA) and poly(cyclohexyl methacrylate) (PCHM) grafted, plasma treated, and untreated fibers were determined. The model successfully predicts the tan δ response of the composites including peak height variations and the development of additional loss dispersions associated with the interphase. Moreover, the model yields a fiber reinforcement efficiency factor, K, which gives a quantitative measure of adhesion. The contact angle of PBA and PCHM grafted high density polyethylene (HDPE) films are also included and are compared to the contact angle of plasma treated fibers. The results indicate that PBA and PCHM grafts enhance adhesion through polymer graft/matrix interactions, not simply by improved wetting.     

Field and spatial geometry dependencies of the electron and holeionization rates in GaAs/AlGaAs multiquantum well APD's

Numerical calculations are presented of the electron and hole ionization rates in GaAs/AlGaAs multiquantum-well APDs (avalanche photodiodes) as a function of the applied electric field and the spatial geometries, i.e., the barrier- and well-layer widths, respectively. The model is calibrated to existing experimental data on bulk GaAs materials and then extrapolated to the multiquantum well structure. It is found that at high electric field strengths the net ionization rate approaches the weighted average of the constituent bulk rates; the potential discontinuity is relatively insignificant. The potential discontinuity most greatly affects the electron ionization rate at low applied electric field strengths within a spatially symmetric structure. It is further determined that the electron-to-hole ionization rate ratio is greatest at low applied electric fields with a spatially symmetric structure with equal well and barrier widths