85 resultados para Indoor pollutants
Resumo:
A resazurin (Rz) based photocatalyst activity indicator ink (paii) is used to test the activity of commercial self-cleaning materials. The semiconductor photocatalyst driven colour change of the ink is monitored indoors and outside using a simple mobile phone application that measures the RGB colour components of the digital image of the paii-covered, irradiated sample in real time. The results correlate directly with those generated using a traditional, lab-bound method of analysis (UV–vis spectrophotometry).
Resumo:
In this paper we investigate the received signal characteristics of a mobile chest-worn transmitter at 5.8 GHz within a high multipath indoor environment. The off-body channel measurements considered both the co- and cross-polarized received signal for both line-of-sight (LOS) and non-LOS (NLOS) conditions. A straightforward channel model based upon the estimated path loss, a lognormal slow fading component and Ricean small-scale fading contribution is developed and used to perform simulations which allow the generation of first order received signal power characteristics.
Resumo:
Active radio-frequency identification systems that are used for the localisation and tracking of people will be subject to the same body centric processes that impact other forms of wearable communications. To achieve the goal of creating body worn tags with multiyear life spans, it will be necessary to gain an understanding of the channel conditions which are likely to impact the reader-tag interrogation process. In this paper we present the preliminary results of an indoor channel measurement campaign conducted at 868 MHz aimed at understanding and modelling signal characteristics for a wrist-worn tag. Using a model selection process based on the Akaike Information Criterion, the lognormal distribution was selected most often to describe the received signal amplitude. Parameter estimates are provided so that the channels investigated in this study may be readily simulated.
Resumo:
Ectomycorrhizal fungi and saprotrophic microorganisms coexist and interact in the mycorrhizosphere. We review what is known regarding these interactions and how they may influence processes such as ectomycorrhiza formation, mycelial growth, and the dynamics of carbon movement to and within the rhizosphere. Particular emphasis is placed on the potential importance of interactions in decomposition of soil organic matter and degradation of persistant organic pollutants in soil. While our knowledge is currently fairly limited, it seems likely that interactions have profound effects on mycorrhizosphere processes. More extensive research is warranted to provide novel insights into mycorrhizosphere ecology and to explore the potential for manipulating the ectomycorrhizosphere environment for biotechnological purposes.
Resumo:
The southern industrial rivers (Aire, Calder, Don and Trent) feeding the Humber estuary were routinely monitored for a range of chlorinated micro- organic contaminants at least once a week over a 1.5-year period. Environmental Quality Standards (EQSs) for inland waters were set under the European Economic Community for a limited number of problematic contaminants (18). The results of the monitoring program for seven classes of chlorinated pollutants on the EQS list are presented in this study. All compounds were detected frequently with the exception of hexachlorobutadiene (where only one detectable measurement out of 280 individual samples occurred). In general, the rivers fell into two classes with respect to their contamination patterns. The Aire and Calder carried higher concentrations of micro- pollutants than the Don and Trent, with the exception of hexachlorobenzene (HCB). For Σ hexachlorocyclohexane (HCH) isomers (α + γ) and for dieldrin, a number of samples (~ 5%) exceeded their EQS for both the Aire and Calder. Often, ΣHCH concentrations were just below the EQS level. Levels of p,p'- DDT on occasions approached the EQS for these two rivers, but only one sample (out of 140) exceeded the EQS. No compounds exceeded their EQS levels on the Don and Trent. Analysis of the ratio of γ HCH/αHCH indicated that the source of HCH for the Don and Trent catchments was primarily lindane (γHCH) and, to a lesser extent, technical HCH (mixture of HCH isomers, dominated by α HCH), while the source(s) for the Aire and Calder had a much higher contribution from technical HCH.
Resumo:
Persistent organic pollutants (POPs) are toxic substances, highly resistant to environmental degradation, which can bio-accumulate and have long-range atmospheric transport potential (UNEP 2001). The majority of studies on endocrine disruption have focused on interferences on the sexual steroid hormones and so have overlooked disruption to glucocorticoid hormones. Here the endocrine disrupting potential of individual POPs and their mixtures has been investigated in vitro to identify any disruption to glucocorticoid nuclear receptor transcriptional activity. POP mixtures were screened for glucocorticoid receptor (GR) translocation using a GR redistribution assay (RA) on a CellInsight(TM) NXT High Content Screening (HCS) platform. A mammalian reporter gene assay (RGA) was then used to assess the individual POPs, and their mixtures, for effects on glucocorticoid nuclear receptor transactivation. POP mixtures did not induce GR translocation in the GR RA or produce an agonist response in the GR RGA. However, in the antagonist test, in the presence of cortisol, an individual POP, p,p'-dichlorodiphenyldichloroethylene (DDE), was found to decrease glucocorticoid nuclear receptor transcriptional activity to 72.5% (in comparison to the positive cortisol control). Enhanced nuclear transcriptional activity, in the presence of cortisol, was evident for the two lowest concentrations of perfluorodecanoic acid (PFOS) potassium salt (0.0147mg/ml and 0.0294mg/ml), the two highest concentrations of perfluorodecanoic acid (PFDA) (0.0025mg/ml and 0.005mg/ml) and the highest concentration of 2,2',4,4'-tetrabromodiphenyl ether (BDE 47) (0.0000858mg/ml). It is important to gain a better understanding of how POPs can interact with GRs as the disruption of glucocorticoid action is thought to contribute to complex diseases.
Resumo:
This paper investigates the characteristics of the shadowed fading observed in off-body communications channels at 5.8 GHz using the κ-μ / gamma composite fading model. Realistic measurements have been conducted considering four individual scenarios namely line of sight (LOS) and non-LOS (NLOS) walking, rotation and random movements within an indoor laboratory environment. It is shown that the κ-μ / gamma composite fading model provides a better fit to the fading observed in off-body communications channels compared to the conventional Nakagami-m and Rician fading models.