Synchronisation control of electric motors through adaptive disturbance cancellation

A master–slave synchronisation control problem is addressed for current-fed DC and permanent magnet synchronous motors with all uncertain parameters. A measurable exogenous rotor position reference signal, which belongs to the class of biased sinusoidal signals with uncertain bias, amplitude, angular frequency, phase, is to be tracked without assuming its a priori knowledge. An innovative modification of disturbance cancellation techniques allows to prove that an output feedback adaptive nonlinear control scheme, which simply generalises the classical internal-model-based input law, solves the aforementioned problem, with an overall stability proof concerning the entire closed-loop system. The practical effectiveness of the proposed approach is illustrated by experimental results.     

The effect of compaction pressure on the conductivity and structure in undoped poly(1,4-phenylene) (PPP)

Poly(paraphenylene) has been prepared according to two different procedures. The d.c. conductivity measurements, obtained under compaction pressure, were correlated to the structural modifications undergone in the same pressure range. X-ray diffraction line profile analysis has been applied to determine the variations in the microstructural parameters.     

Conformational and packing energy calculations on the two crystalline modifications of poly (trans-1,4-butadiene)

Conformational and packing energy calculations have been performed on the two crystalline modifications of poly(trans-1,4-butadiene), and the results have been compared with experimental data. The conformational energy calculations predict the chain axis and conformation of the modification that is stable below 76°C, without any a priori assumption. Packing energy calculations on this modification show that the best space group is P2₁/a and the position of the chains is in good agreement with X-ray data. Conformational energy calculations on the modification that is stable above 76°C predict that the lowest energy conformation is a statistical sequence with a random distribution of the three minimum torsion angles around the single bonds adjacent to the double bond, with a trans conformation around the other single bond.     

Prevalence of sensitization to Cupressus sempervirens: a 4-year retrospective study

In the last few years Cupressus sempervirens has been identified as the cause of an increasing number of cases of late winter-early spring pollinosis in Mediterranean countries. We conducted a 4-year retrospective study of a large group of subjects with documented allergic respiratory disease in order to determine the prevalence, clinical significance and annual rate of sensitization to C. sempervirens pollen. Anamnestic data and skin prick tests (SPT) with common aeroallergens and C. sempervirens extract were collected from 1397 subjects (712 male and 685 female) resident in Latium, a region in central Italy, with complaints related to upper- or lower-respiratory-tract disorders or conjunctival disease. Two hundred and forty-three subjects (17.4%) showed positive results to C. sempervirens extract; 47 (19.3%) of them were monosensitized. The annual sensitization rate of SPT positivity to C. sempervirens varied from 7.2% in 1995 to 22% in 1998. All the subjects monosensitized to cypress pollen had symptoms from January through April. Our study suggests that sensitivity to C. sempervirens is responsible for respiratory symptoms in an increasing percentage of subjects. Further studies are needed to determine its frequency at the national level.     

Modeling residential indoor concentrations of PM2.5, NO2, NOx,and secondhand smoke in the Subpopulations and Intermediate Outcome Measures in COPD (SPIROMICS) Air study

Increased outdoor concentrations of fine particulate matter (PM_2.5) and oxides of nitrogen (NO₂, NO_x) are associated with respiratory and cardiovascular morbidity in adults and children. However, people spend most of their time indoors and this is particularly true for individuals with chronic obstructive pulmonary disease (COPD). Both outdoor and indoor air pollution may accelerate lung function loss in individuals with COPD, but it is not feasible to measure indoor pollutant concentrations in all participants in large cohort studies. We aimed to understand indoor exposures in a cohort of adults (SPIROMICS Air, the SubPopulations and Intermediate Outcome Measures in COPD Study of Air pollution). We developed models for the entire cohort based on monitoring in a subset of homes, to predict mean 2-week–measured concentrations of PM_2.5, NO₂, NO_x, and nicotine, using home and behavioral questionnaire responses available in the full cohort. Models incorporating socioeconomic, meteorological, behavioral, and residential information together explained about 60% of the variation in indoor concentration of each pollutant. Cross-validated R² for best indoor prediction models ranged from 0.43 (NO_x) to 0.51 (NO₂). Models based on questionnaire responses and estimated outdoor concentrations successfully explained most variation in indoor PM_2.5, NO₂, NO_x, and nicotine concentrations.     

Hydrophilic–oleophobic behaviour in thin films from fluoromodified nanoclays and polystyrene

New nanocomposite thin films were prepared by spin coating technique from polystyrene (PS) and montmorillonite (MMT) modified with perfluoropolyether cationic ammonium salts (FOMMT). The coating thickness was tuned by changing the solution concentration, and it was measured by the scratching method with atomic force microscopy (AFM). Demodulation AFM images of the higher thickness (>100 nm) PS/FOMMT nanocomposite coating do not show any phase difference suggesting the formation of a homogeneous structure, while the corresponding demodulation image of the lower thickness (ca. 60 nm) PS/FOMMT nanocomposite film revealed the presence of two different phases, which may be attributed to fluoromodified clays and polystyrene. Surface characterization was made through contact angle (CA) measurements and it showed unexpectedly low surface tension dispersive component γ _s ^d (around 12 mN/m) and a very high polar components γ _s ^d (50 mN/m) in the case of the lower thickness PS/FOMMT nanocomposite coating.     

Remediation of waters contaminated with MCPA by the yeasts Lipomyces starkeyi entrapped in a sol-gel zirconia matrix

A single-stage sol-gel route was set to entrap yeast cells of Lipomyces starkeyi in a zirconia (ZrO(2)) matrix, and the remediation ability of the resulting catalyst toward a phenoxy acid herbicide, 4-chloro-2-methylphenoxyacetic acid (MCPA), was studied. It was found that the experimental procedure allowed a high dispersion of the microorganisms into the zirconia gel matrix; the ZrO(2) matrix exhibited a significant sorption capacity of the herbicide, and the entrapped cells showed a degradative activity toward MCPA. The combination of these effects leads to a nearly total removal efficiency (>97%) of the herbicide at 30 °C within 1 h incubation time from a solution containing a very high concentration of MCPA (200 mg L(-1)). On the basis of the experimental evidence, a removal mechanism was proposed involving in the first step the sorption of the herbicide molecules on the ZrO(2) matrix, followed by the microbial degradation operated by the entrapped yeasts, the metabolic activity of which appear enhanced under the microenvironmental conditions established within the zirconia matrix. Repeated batch tests of sorption/degradation of entrapped Lipomyces showed that the removal efficiency retained almost the same value of 97.3% after 3 batch tests, with only a subsequent slight decrease, probably due to the progressive saturation of the zirconia matrix.     

Influence of the Atmosphere Composition during Malaxation and Storage on the Shelf Life of an Unfiltered Extra Virgin Olive Oil: Preliminary Results

The nutraceutical and organoleptic quality of the extra virgin olive oil (EVOO) depends on a process that begins with the olive ripening and ends with the packaging and storage. As the EVOO quality decay is mainly induced by the oxidation process, the gaseous composition of the atmosphere during both malaxation and storage can play a key role. Because of that, the aim of this research work is to determine the influence of the gaseous composition of the atmosphere used during malaxation and storage on an unfiltered EVOO shelf life, and to individuate the best “malaxation atmosphere × storage atmosphere” combination to adopt to more effectively slow down the oil quality decay rate during storage. The combined experimental conditions used during malaxation and storage significantly affect the quality decay rate of the EVOO over one year of storage for all the evaluated parameters. In conclusion, the gaseous composition of the atmosphere used during both malaxation and storage deeply affects the shelf life of the unfiltered EVOO as regards its chemical and sensory features, especially when air is used. On the contrary, the best results are obtained when an inert gas (nitrogen or argon) is used during both phases. Practical Applications : The regular consumption of EVOO represents one of the main cornerstones of the Mediterranean diet. According to the FDA (Food and Drug Administration), this product can be considered as a healthy food because of its extraordinary nutraceutical and organoleptic properties, so that if consumers consume half a tablespoon of olive oil per day—without increasing their daily calorie intake—they can significantly reduce the incidence of several degenerative diseases as well as the risks associated with them. The knowledge of the impact of different “malaxation atmosphere × storage atmosphere” combinations on the quality decay rate during storage of an unfiltered EVOO can allow to identify the best operating conditions to be used during its production and storage, in order to preserve the nutraceutical and organoleptic properties of this product over time, thus extending its commercial life in terms of both quality parameters and healthy properties.