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Cremona, Italy

Ferrer A.,App Quality
Quality Engineering | Year: 2014

The basic fundamentals of statistical process control (SPC) were proposed by Walter Shewhart for data-starved production environments typical in the 1920s and 1930s. In the 21st century, the traditional scarcity of data has given way to a data-rich environment typical of highly automated and computerized modern processes. These data often exhibit high correlation, rank deficiency, low signal-to-noise ratio, multistage and multiway structures, and missing values. Conventional univariate and multivariate SPC techniques are not suitable in these environments. This article discusses the paradigm shift to which those working in the quality improvement field should pay keen attention. We advocate the use of latent structure-based multivariate statistical process control methods as efficient quality improvement tools in these massive data contexts. This is a strategic issue for industrial success in the tremendously competitive global market. © Copyright Taylor and Francis Group, LLC. Source

Laws B.V.,Colorado School of Mines | Dickenson E.R.V.,Colorado School of Mines | Johnson T.A.,Water Replenishment District of Southern California WRD | Snyder S.A.,App Quality | Drewes J.E.,Colorado School of Mines
Science of the Total Environment | Year: 2011

The attenuation of a diverse suite of contaminants of emerging concern (CECs) and bulk water quality changes was evaluated at a surface-spreading aquifer recharge operation across a detailed subsurface profile (9 locations), representing both short- and long-travel times (10. h to 60. days). Seventeen CECs were detected in the recharge basin and the concentrations of all were reduced during soil aquifer treatment (SAT), with 11 of the target compounds attenuated by > 80% after 60. days of travel time. Select CECs (atenolol, gemfibrozil, N,. N-diethly-3-methylbenzamide, meprobamate, tris(2-chloroethyl)phosphate, and primidone) and bulk water organic-carbon measurements (total organic carbon, biodegradable organic carbon, size-exclusion chromatography and fluorescence excitation-emission matrices) were identified as monitoring parameters that can be used to assess SAT performance at surface-spreading operations. © 2010 Elsevier B.V. Source

Wert E.C.,App Quality
Journal - American Water Works Association | Year: 2014

The removal of biodegradable ozone by-products was evaluated at pilot scale using a fixed-bed biofilm reactor (FBBR) containing spherical plastic support media. Six FBBRs were operated in parallel with varying media sizes (1-, 1.25-, or 2-in. diameter) and empty bed contact times (EBCTs; 6 or 12 min). Influent water was provided from a full-scale water treatment plant following ozonation, coagulation, and flocculation processes. After seven months of operation, pseudosteady-state conditions were achieved with up to 50% removal of assimilable organic carbon (AOC) and up to 40% reduction in ultraviolet absorbance at 254 nm (UV254). Increases in FBBR effluent turbidity and head loss were also indicative of biomass development and sloughing. Process efficiency deteriorated because of the consumption of biomass by snails and other invertebrates. © 2014 Koch Membrane Systems, Inc. Source

Perfumes are manufactured by mixing odorous materials with different volatilities. The parameter that measures the lasting property of a material when applied on the skin is called substantivity or tenacity. It is well known by perfumers that citrus and green notes are perceived as fresh and they tend to evaporate quickly, while odors most dissimilar to 'fresh' (e.g., oriental, powdery, erogenic and animalic scents) are tenacious. However, studies aimed at quantifying the relationship between fresh odor quality and substantivity have not received much attention. In this work, perceptual olfactory ratings on a fresh scale, estimated in a previous study, were compared with substantivity parameters and antierogenic ratings from the literature. It was found that the correlation between fresh odor character and odorant substantivity is quite strong (r = -0.85). 'Fresh' is sometimes interpreted in perfumery as 'cool' and the opposite of 'warm'. This association suggests that odor freshness might be somehow related to temperature. Assuming that odor perception space was shaped throughout evolution in temperate climates, results reported here are consistent with the hypothesis that 'fresh' evokes scents typically encountered in the cool season, while 'warm' would be evoked by odors found in nature during summer. This hypothesis is rather simplistic but it may provide a new insight to better understand the perceptual space of scents. © 2013 by the authors; licensee MDPI, Basel, Switzerland. Source

Capilla C.,App Quality
WIT Transactions on Ecology and the Environment | Year: 2012

Meteorological variability must be taken into account in the modelling of temporal changes in air pollutants to evaluate emissions reduction strategies. In this paper nitrogen dioxide (NO2) hourly data are analyzed at two monitoring stations in Valencia (Spain). Meteorologically-adjusted nitric oxide (NO) is used as an indicator of traffic density. The low-pass filter developed by Kolmogorov and Zurbenko is used to split the logarithm of NO2 and NO hourly concentrations into long-term, seasonal and short-term components. Meteorological effects are analyzed and removed from filtered pollutants time series. Forward stepwise regression is employed to select the filtered meteorological variables that explain more variability. A natural logarithmic transformation is applied to the series of hourly data and the model for the hourly pollutants concentrations is multiplicative. The dependencies of urban NO2 on the corresponding vehicular emissions and relevant meteorological parameters are non-linear. Long-term components represent a small amount in the overall variability of air pollution data. Seasonal and short-term components mask the underlying relationship between NO2 and emissions if studied as a whole. The pollutant temporal components have to be studied separately due to their different physical and explanatory mechanisms. © 2012 WIT Press. Source

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