Precoat filtration with body-feed and variable pressure. Part I: Mathematical modelling

The precoat filtration with body-feed is an unit operation of agricultural and food engineering. Mostly it is implemented by using centrifugal pump, which pump curve has a partial horizontal trend. Classically, in filtration theory, this prerogative of the centrifugal pumps leads to the simplifying assumption that filtration occurs with constant pressure. Because of this, it is easy to integrate the Darcy\u2019s differential equation [1, 2 and 3] for the precoat filtration with body-feed, obtaining the well known Carman equation [4]. This is the equation which relates the filtration time with the filtrate volume, the operating pressure, the filter area, and the solid-liquid suspension characteristics. The Carman equation is the start point for the subsequent optimization of the filtration cycles, e.g. by establishing the relationship between the filtration time and the filter cleaning time [5]. A better optimization of the precoat filtration with body-feed could be obtain, with some economic benefits, if an integration of the Darcy ODE was developed starting from actual trend of the pressure produced by the centrifugal pump, that is if a variable pressure was considered, as expected from the pump curve. In this sense a proposal was done by Tiller and Crump [6] many years ago in accordance with a graphic method of integration of the Darcy ODE. However the graphic procedure is tedious since it is iterative and not computerizable. For this reason the aim of this work was to find an analytical solution to the Darcy ODE for the filtration with variable pressure in order to obtain a quick and easy-to-use equation for the subsequent optimization calculations of filtration cycles, even if more complex of the Carman equation

Water sensitive papers simulation to assess deposits on targets

Aim of the study is to assess the possibility to use water sensitive papers to estimate, beside the superficial coverage, also the amount of deposit on the target at varying the spray features. To point out the main quantities influencing the deposit, the behaviour of the water sensitive papers was simulated by assuming some simplifying hypotheses: log-normal distribution of the diameter population of the drops and circular spots. Several images (630) of water sensitive papers, sprayed with drops of different mean diameter (from 100 up to 500 μm), constant coefficient of variation (0.50), and theoretical percentage of covered surface ranging from 10 up to 100%, were produced by means of simulation. These images were considered as effective water sensitive paper images and then analysed by means of an image processing software. The correlations between measured and effective values were studied and they allowed for an estimate of deposit and spray features from the image data. This implies that the analysis of the water sensitive paper images allows the determination of more complex parameters such as the unitary deposit and the impact density, all data strictly related to the efficacy of a phytosanitary treatment

Vibration risk evaluation in hand-held harvesters for olives

This research aims to evaluate the vibration transmitted to the hand-arm system by two electric portable harvesters, different for size and teeth features of the harvesting head. Moreover, being the bars of the two machines telescopic, they were operated at minimum and maximum length. The acceleration was measured, at different times, in two points, 1 m apart, next to the hand positions. Finally, measurements were carried out both at no load, in standard controlled conditions, and in field, under ordinary working conditions. To smooth the influence of external factors, the machines were operated by the same operator. The results showed that the greater and heavier harvesting head produced significantly higher acceleration at no load (10.7 m/s2 vs. 5.5 m/s2), and comparable acceleration at load (13.9 vs. 14.2 m/s2). On average, the vibration was significantly higher at load (14.0 vs. 8.1 m/s2). The difference between the two bar lengths was not statistically significant: 9.4 m/s2 when using the minimum length and 9.8 m/s2 when using the maximum one. Finally, the difference between the two measuring points was affected by the bar length: it was statistically significant when using the bar at its minimum length only. As far as the components are concerned, at no load the highest acceleration was measured along the bar axis for both harvesting heads (9.2 m/s2 for the greater head and 4.2 m/s2 for the smaller one). At load all the three components were comparable in the greater head (about 7.8 m/s2) whereas the x component was predominant in the other one (11.4 vs. 4.8 (y) and 6.6 m/s2 (z))

An innovative pneumatic electrostatic sprayer useful for tendone vineyards

The aim of this note is to analyse the features of the ESS “150 RB14” electrostatic sprayer, an innovative model compared to the standard air-assisted sprayers traditionally used by Apulian growers (Southern Italy) in “tendone” vineyards. The experimental tests showed that the activation of the electrostatic system produced a significant increase in the mean deposit, but it was located only on the foliar layer of the canopy closer to the sprayer. However this result should also imply an increase in the deposits on the bunches when the electrostatic system is activated, even if further tests are necessary to verify this expectation. If this will be substantiated, the electrostatic sprayer ESS “150 RB14” would be suitable for the targeted applications usually performed in “tendone” table grape vineyards

Continence and complications rates after male slings as primary surgery for post-prostatectomy incontinence: A systematic review

Objectives: to analyze continence and complications rates after male slings as first line surgical treatment, in order to improve patient counseling for the management of SUI postprostatectomy. Method: A MedLine search using specified search terms was done on January 23, 2012. This research rendered 160 records. Results: No controlled trial was available for analysis. The majority of papers dealing with out- come and complications came from a few centres. At a median follow-up of 15 months the pooled cure rates for all kinds of slings was 77.4; in the AdVance group the pooled cure rates was 72.5%; in the InVance group it was 74.2% while in the Remeex group it was 84.3%. Conclusions: Only a few number observational studies addressed review selection criteria. The pooled overall cure rates is high but there are no data concerning reliable pre- and postopera- tive prognostic factors affecting treatment failure and complications rates, thus it is not possi- ble to have suitable criteria for a better patient selection. The statistically pooled results obtained should be interpreted with caution because of several limitations due to several study selection limitations: observational study design, few number of analysed studies, heterogene- ity, lack of outcome definition and standardisation, between-study variability, high risk of bias

PROPOSTE PER UNA LETTURA LINGUISTICA DEL PETRARCHISMO FEMMINILE DEL XVI SECOLO: PRIMI SONDAGGI SU VERONICA GAMBARA, VITTORIA COLONNA E GASPARA STAMPA

Finora la critica letteraria, specie negli ultimi anni, ha dedicato sempre maggiore attenzione alle petrarchiste del Cinquecento, in particolar modo soffermandosi sulle vicende personali delle poetesse, sulle tematiche, sull’intertestualità, con occasionali osservazioni stilistiche, mentre mancano ad oggi studi specifici sulla lingua di questa importante produzione lirica. Il contributo offre i primi risultati tendenziali di un ampio studio in corso, che si propone di colmare questa lacuna negli studi linguistici sul Cinquecento. Si presentano qui i risultati di una prima ricognizione linguistica, condotta sui componimenti poetici di Veronica Gambara, Vittoria Colonna e Gaspara Stampa. In particolare, si indagano il lessico e la fraseologia al fine di valutarne la composizione e di verificare elementi di discontinuità ed eventuali novità rispetto al modello petrarchesco e alla tradizione poetica precedente.   Proposals for a linguistic reading of 16th-century female Petrarchism: initial surveys of Veronica Gambara, Vittoria Colonna, and Gaspara Stampa   Literary criticism, especially in recent years, has devoted increasing attention to women petrarchists of the sixteenth century, especially dwelling on the personal histories of the poets, themes, and intertextuality, with occasional stylistic observations, while specific studies on the language of this important lyric production are still lacking. The contribution offers the first tentative results of a large ongoing study, which aims to fill this gap in linguistic studies on the sixteenth century. The results of an initial linguistic reconnaissance, conducted on the poetic compositions of Veronica Gambara, Vittoria Colonna and Gaspara Stampa, are presented here. In particular, the lexicon and phraseology are investigated to assess their composition and to verify elements of discontinuity and possible novelty with respect to the Petrarchan model and the earlier poetic tradition

Special Issue on Pesticide Applications in Agricultural Systems

The European Directive 2009/128/EC on the Sustainable Use of Pesticides recognizes the use of Plant Protection Products (PPP) as having great impact on human health and the environment [...

The periodic repolarization dynamics index identifies changes in ventricular repolarization oscillations associated with music-induced emotions

The effect of music on cardiovascular dynamics may be useful in a variety of clinical settings. The aim of this study was to assess whether listening to music characterized by different emotional valence affected ventricular periodic repolarization dynamics (PRD), a recently-proposed non-invasive index of sympathetic ventricular modulation. The 12 lead ECG was recorded in 71 healthy volunteers exposed to six 90 s excerpts of pleasant music and unpleasant acoustic stimuli as well as six 90 s intervals of silence. A 20 s interval was allowed between excerpts during which the participants were asked to evaluate the previous excerpt. A simulation study was carried out to assess the capability of the algorithm of tracking fast small changes in PRD. The simulation study shows that the algorithm implemented in this study has a time-frequency resolution sufficient to capture the fast dynamics observed in this study. PRD were higher during listening to both pleasant and unpleasant music than during silence. There was a (weak) trend for the PRD to be higher during listening to pleasant than unpleasant music that may indicate the existence of a (weak) interaction between the valence of music-induced emotions and sympathetic ventricular response. The PRD significantly increased during the 20 s interval in between conditions, possibly reflecting a sympathetic response to the evaluation task and/or to the expectation of the following excerpt

Operator Dermal Exposure to Pesticides in Tomato and Strawberry Greenhouses from Hand-Held Sprayers

Protection of greenhouse crops in southern Italy usually requires 15–20 phytosanitary treatments per year, with volume rates in the range of 1000–2000 L ha1, depending on the plant growth stage. The most widespread sprayers are hand-held, high-pressure devices, which may expose operators to high levels of pesticides. This paper, also with the aim to lead toward a more sustainable use of greenhouses in agricultural productions, including some aspects of workers’ safety, reports the results of experimental tests aimed at measuring the amount of the mixture deposited on the worker’s body (potential dermal exposure, PDE) during pesticide applications to tomato and strawberry plants in a protected environment. Experimental tests on tomatoes were carried out taking into account two plant growth stages (flowering and senescence), two types of spray lance, two working pressures (1 and 2 MPa), and two walking directions (forwards and backwards). Those on the strawberries were carried out at the maturity of the fruit growth stage, comparing two hand-held sprayers (a standard spray gun and a short hand-held spray boom equipped with two nozzles) and working according to the common practice: forwards movement of the operator and high pressure (2 MPa). The results showed that with the tomato plants, the most important factor in reducing the deposit on the operator was the walking direction: on average, the PDE was 718 mL per 1000 L of the sprayed mixture (0.72h) while walking forwards and 133 mL (0.13h) while walking backwards. The reduction factor ranged from 3.0 at the flowering growth stage to 7.2 at the senescence growth stage. With respect to the strawberry plants, the PDE was significantly higher when the operator used the short hand-held spray boom (887 mL per 1000 L of the sprayed mixture, equivalent to 0.89h), rather than the spray gun (344 mL, 0.34h). In both cases, the most exposed body parts were the lower limbs, which accounted for 89–94% of the total PDE

Simulation of Water Sensitive Papers for Spray Analysis

Aim of this study was to simulate the water sensitive paper (WSP) behaviour for estimate the unitary spray deposition on the target at varying spray features and target coverage.  WSP images were produced assuming some simplifying hypotheses: spherical drops and circular stains randomly placed on the images. Sprays were described in terms of probability distribution function (PDF) of drop size (log-normal and Rosin-Rammler), coefficient of variation of diameters (CV), arithmetic mean diameter (AMD), and volume median diameter (VMD).  The results from the simulations showed that the overlap between stains was independent of spray features: when the percentage of covered surface of WSP images ranged from 4.7 up to 61.6%, the overlap between stains ranged from 0.3 up to 33.4%.   On the contrary, unitary deposit (volume per square centimetre, mL cm-2) and particle density (number of distinct particles per square centimetre, cm-2) could be obtained from the percentage of covered surface if CV, AMD, VMD and PDF were known.  However, assuming as spray parameter the VMD, the drop size distribution had almost no effect on the unitary deposit: with the same percentage of covered surface, the Rosin-Rammler PDF provided an estimate of the unitary deposit higher than log-normal distribution between 5 and 7% only