optimization of solar integration in biomass fuelled steam plants

Abstract This paper is focused on solar-biomass integration and presents a thermodynamic analysis of solar power utilization replacing the steam bleeds of a regenerative Hirn cycle plant, biomass fuelled, in feedwater pre heating process. In solar-biomass integrated configuration an energy conversion efficiency of solar energy has been evaluated in order to compare the use of solar energy in solo and hybrid configurations. Such efficiency has been adopted as optimization parameter for the best hybrid plant configuration, varying steam pressure and regeneration parameters

Pricing and Hedging Asian Basket Options with Quasi-Monte Carlo Simulations

In this article we consider the problem of pricing and hedging high-dimensional Asian basket options by Quasi-Monte Carlo simulation. We assume a Black-Scholes market with time-dependent volatilities and show how to compute the deltas by the aid of the Malliavin Calculus, extending the procedure employed by Montero and Kohatsu-Higa (2003). Efficient path-generation algorithms, such as Linear Transformation and Principal Component Analysis, exhibit a high computational cost in a market with time-dependent volatilities. We present a new and fast Cholesky algorithm for block matrices that makes the Linear Transformation even more convenient. Moreover, we propose a new-path generation technique based on a Kronecker Product Approximation. This construction returns the same accuracy of the Linear Transformation used for the computation of the deltas and the prices in the case of correlated asset returns while requiring a lower computational time. All these techniques can be easily employed for stochastic volatility models based on the mixture of multi-dimensional dynamics introduced by Brigo et al. (2004).Comment: 16 page

An attempt of biocontrol the tomato-wilt disease caused by Verticillium dahliae using Burkholderia gladioli pv. agaricicola and its bioactive secondary metabolites

There is a great interest in discovering new microbial natural biocides such as microbial secondary metabolites to reduce the environmental pollution due to the excessive use of synthetic pesticides. Verticillium wilt, caused by the soil-borne Verticillium dahliae, is a widespread disease in tomato growing in many parts of the world. Burkholderia gladioli pv. agaricicola produces some antimicrobial substances and extracellular hydrolytic enzymes which exhibited promising antimicrobial activity towards several phytopathogens. The aims of the current research are to assess in vitro fungicidal effect of 4 strains of B. gladioli pv. agaricicola (ICMP11096, 11097, 12220 and 12322) against V. dahliae using culture or cell-free culture filtrate. In situ assay was performed to evaluate the biocontrol effect of the most efficient bacterial strain on wilt disease caused by V. dahliae in tomato plants. Results demonstrated that the studied bacterial strain ICMP12322 exerted the highest in vitro antifungal activity against V. dahliae which correlated with its ability to produce extracellular hydrolytic enzymes. Furthermore, in situ results showed that the selected bacterial strain significantly minimized the disease incidence

On the spatial distribution of dark matter halos

We study the spatial distribution of dark matter halos in the Universe in terms of their number density contrast, related to the underlying dark matter fluctuation via a non-local and non-linear bias random field. The description of the matter dynamics is simplified by adopting the `truncated' Zel'dovich approximation to obtain both analytical results and simulated maps. The halo number density field in our maps and its probability distribution reproduce with excellent accuracy those of halos in a high-resolution N-body simulation with the same initial conditions. Our non-linear and non-local bias prescription matches the N-body halo distribution better than any Eulerian linear and local bias.Comment: 4 pages, LaTeX (uses emulateapj; included psfig.tex), 3 figures, 1 table. Shortened version, matching the size requirements of ApJ Letters. Accepted for publicatio

Real-time evaluation of two light delivery systems for photodynamic disinfection of Candida albicans biofilm in curved root canals

Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 μM) was introduced into the canals and then irradiated (λ = 660 nm, P = 100 mW, beam diameter = 2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, grant 2010/13313-9)Conselho Nacional de Pesquisas (Brazil) Conselho Nacional de Desenvolvimento Cientifico e TecnologicoNational Institute of Mental Health (U.S.) (NIH R01AI050875

Comparison of indoor and outdoor fungi and particles in poultry units

A descriptive study was developed in order to compare indoor and outdoor air contamination caused by fungi and particles in seven poultry units. Twenty eight air samples of 25 litters were collected through the impaction method on malt extract agar. Air sampling and particles concentration measurement were done in the interior and also outside premises of the poultries’ pavilions. Regarding the fungal load in the air, indoor concentration of mold was higher than outside air in six poultry units. Twenty eight species / genera of fungi were identified indoor, being Scopulariopsis brevicaulis (40.5%) the most commonly isolated species and Rhizopus sp. (30.0%) the most commonly isolated genus. Concerning outdoor, eighteen species/genera of fungi were isolated, being Scopulariopsis brevicaulis (62.6%) also the most isolated. All the poultry farms analyzed presented indoor fungi different from the ones identified outdoors. Regarding particles’ contamination, PM2.5, PM5.0 and PM10 had a statistically significant difference (Mann-Whitney U test) between the inside and outside of the pavilions, with the inside more contaminated (p=.006; p=.005; p=.005, respectively). The analyzed poultry units are potential reservoirs of substantial amounts of fungi and particles and could therefore free them in the atmospheric air. The developed study showed that indoor air was more contaminated than outdoors, and this can result in emission of potentially pathogenic fungi and particles via aerosols from poultry units to the environment, which may post a considerable risk to public health and contribute to environmental pollution

Accessing occupational exposure to fungi in a cork industry

In this study we aimed to access fungal exposure in workers from one cork industry through the mycological analysis of their nasal exudate and the environmental fungal contamination of their surroundings as well. Nasal mucous samples from 127 workers were taken with sterilized cotton swabs.The fungal species identified in the collected nose swabs were shown to be correlated with the results obtained in the environment. Eighty workers (63.0%) presented contamination of their nose nostril with Chrysonilia sitophila, which number of colonies was countless. Within the Aspergillus genus, the complexes Fumigati, Circumdati, Versicolores and Candidi were isolated. No azole-resistant Aspergillus isolates grew in the selective media used (screened itraconazole and voriconazole resistance).This approach allowed us to estimate the risk associated with these tasks performance. Moreover, the cork industry is related to high dust contamination and this can promote exposure to fungi since dust particles can act as carriers of fungi to the worker’s nose. Assessment by molecular tools will ensure the specific targeting of DNA from P. glabrum complex in workers nose

Non-destructive testing of stone biodeterioration and biocleaning effectiveness

Microorganisms (bacteria, green algae and fungi) may lead to complex problems in the conservation of cultural heritage assets due to their biodeteriorative potential. The biodeterioration phenomena observed on materials of cultural heritage is determined by several factors, such as climatic conditions, chemical composition and nature of the material itself, as well as biological colonizers. The combination of several non-destructive techniques is compulsory in the field of cultural heritage in order to develop and design new and effective conservation strategies to prevent, control and minimize the causes of decay. For instance, Confocal Laser Scanning Microscopy (CLSM) permits to detect the presence, the penetration depth and the spatial organization of different phototrophic microorganisms established on stone surfaces, as well as Digital Image Analysis allows quantifying the surface area covered by microorganisms without destroying the sample. In this study, these non-destructive instrumental analyses, together with in vitro chlorophyll a quantification, were applied in order to evaluate a new procedure of stone cleaning consisting of the application of secondary metabolites with biocide properties. Three different natural biocides were tested on Hontoria limestone samples, a biosparitic limestone used in many Spanish monuments, previously inoculated with a multi-species phototrophic culture. After 1 month of biofilm growth on Hontoria limestone samples, the following biocides were applied: - culture filtrates of the fungus Trichoderma harzianum T-22 strain, - culture filtrates of the bacterium Burkholderia gladioli pv. agaricicola ICMP (Bga) 11096 strain, - glycoalkaloids (GLAs) extract from unripe berries of Solanum nigrum. After one month of incubation, CLSM revealed that none of the treatments was efficient against all inoculated phototrophic species, probably due to different biocide resistance. This was also corroborated by spectrophotometric determination of chlorophyll a and digital image analysis. Among all treatments, the culture filtrates of T.harzianum and the GLAs’ extract showed higher biocidal efficiency than the Bga culture filtrate. It seems evident that non-destructive analysis and ecological cleaning methods can represent a innovative strategy for the protection of our stone cultural heritage. Further work on the biocidal effectiveness and durability of secondary metabolites in the medium and long-term is needed for the design of effective and sustainable treatments for minimizing or eradicate stone biodeteriorationPeer Reviewe

Modelo físico de sistema de produção de leite para as mesorregiões metropolitana de Belém e Nordeste paraense.

Publicado também na página 230