Solution of the Percus-Yevick equation for hard discs

We solve the Percus-Yevick equation in two dimensions by reducing it to a set of simple integral equations. We numerically obtain both the pair correlation function and the equation of state for a hard disc fluid and find good agreement with available Monte-Carlo calculations. The present method of resolution may be generalized to any even dimension.Comment: 9 pages, 3 figure

Preliminary studies of geochemical tools to traceability of Sicilian honey

Today is increasing the attention of consumers for the origin of food and high reputation of products with a distinct geographical identity. Food traceability is an important issue in food safety and quality control, with impacts on food security, its quantity and overall availability. Furthermore, the possibility of tracing the origin of foodstuff is assuming an increasingly important role at the legislative level, as a tool that may allow to prove on product authenticity and to control adulteration So, establish systems to trace food or feed products through specified stages of production, processing and distribution play a key role also to ensure food safety. For these reason, in the last years, a various of analytical techniques have been tested to found ways to establish the geographical origin of different kinds of food and many works reported that the combination of different analytical methods associated a multifactorial analysis of the data seems to be the most promising system to establish univocal traceability systems. Despite, the honey is a well appreciated natural product in the world and the detection of potential fraud could be favored through tools linking the chemistry composition of this production to producing area. A relatively small number of investigations regarding traceability of honey can be found in the scientific literature. Therefore, in these contest the development of fingerprinting techniques based on the determination of the specific markers of provenance analyzed whit chemometric approach represents an interesting area of research. Recent works have been demonstrated the potentiality of the study of the distribution patterns of rare earth as a promising analytical method for traceability of food products due coherent and predictable chemical behaviour of these compounds. Also, have been demonstrated that their distribution in soil keeps unaltered in plants growing on that soil and eventually in agricultural products obtained from those plants and through the normalization of the REEs distribution, it is possible to appreciate their relative enrichments in soil-plant- agro food products The aim of the research is to observe if the REEs normalizated pattern of honey is kept unaltered respect the soils of production to establish a correlation between geographic area and honey product. In this first study the REE approach, give very intriguing results in the geographical traceability of honey samples. The results have been supported by statistical treatment. A larger study is in progress to optimize the analytical methodology and to extend the research to a major number of sample for a better geographical characterization

A prototypical model for tensional wrinkling in thin sheets

The buckling and wrinkling of thin films has recently seen a surge of interest among physicists, biologists, mathematicians and engineers. This has been triggered by the growing interest in developing technologies at ever decreasing scales and the resulting necessity to control the mechanics of tiny structures, as well as by the realization that morphogenetic processes, such as the tissue-shaping instabilities occurring in animal epithelia or plant leaves, often emerge from mechanical instabilities of cell sheets. While the most basic buckling instability of uniaxially compressed plates was understood by Euler more than 200 years ago, recent experiments on nanometrically thin (ultrathin) films have shown significant deviations from predictions of standard buckling theory. Motivated by this puzzle, we introduce here a theoretical model that allows for a systematic analysis of wrinkling in sheets far from their instability threshold. We focus on the simplest extension of Euler buckling that exhibits wrinkles of finite length - a sheet under axisymmetric tensile loads. This geometry, whose first study is attributed to Lam´e, allows us to construct\ud a phase diagram that demonstrates the dramatic variation of wrinkling patterns from near-threshold to far-from-threshold conditions. Theoretical arguments and comparison to experiments show that for thin sheets the far-from-threshold regime is expected to emerge under extremely small compressive loads, emphasizing the relevance of our analysis for nanomechanics applications

Capillary deformations of bendable films

We address the partial wetting of liquid drops on ultrathin solid sheets resting on a deformable foundation. Considering the membrane limit of sheets that can relax compression through wrinkling at negligible energetic cost, we revisit the classical theory for the contact of liquid drops on solids. Our calculations and experiments show that the liquid-solid-vapor contact angle is modified from the Young angle, even though the elastic bulk modulus (E) of the sheet is so large that the ratio between the surface tension γ and E is of molecular size. This finding establishes a new type of “soft capillarity” that stems from the bendability of thin elastic bodies rather than from material softness. We also show that the size of the wrinkle pattern that emerges in the sheet is fully predictable, thus resolving a puzzle noticed in several previous attempts to model “drop-on-a-floating-sheet” experiments, and enabling a reliable usage of this setup for the metrology of ultrathin films

Do ultrafast exciton-polaron decoherence dynamics govern photocarrier generation efficiencies in polymer solar cells?

All-organic-based photovoltaic solar cells have attracted considerable attention because of their low-cost processing and short energy payback time. In such systems the primary dissociation of an optical excitation into a pair of photocarriers has been recently shown to be extremely rapid and efficient, but the physical reason for this remains unclear. Here, two-dimensional photocurrent excitation spectroscopy, a novel non-linear optical spectroscopy, is used to probe the ultrafast coherent decay of photoexcitations into charge-producing states in a polymer:fullerene based solar cell. The two-dimensional photocurrent spectra are interpreted by introducing a theoretical model for the description of the coupling of the electronic states of the system to an external environment and to the applied laser fields. The experimental data show no cross-peaks in the two-dimensional photocurrent spectra, as predicted by the model for coherence times between the exciton and the photocurrent producing states of 20\,fs or less

Torsional Dynamic Performance of a Transmission Test Bench: An Investigation on the Effect of Motors Controllers Parameters

Besides in-vehicle testing, automotive powertrains and their subsystems are extensively studied and verified, in the different development phases, through dedicated test benches having various mechanical layouts according to the specific target. The torsional load is typically applied to the transmission by electric motors connected at both ends of the driveline. The electric motors drives allow speed and torque closed-loop control so that the desired combination of speed and torque can be imposed over time during the experiment. The parameters of such controllers therefore play a crucial role in the torsional dynamic behavior of the bench and therefore must be carefully selected and tuned to achieve optimal reference tracking and disturbance rejection performance. This paper aims at proposing a model-based sensitivity analysis of the PID controllers parameters starting from an experimentally validated torsional model of a Dual Clutch Transmission test rig. The methodology here proposed also contributes to achieving the Sustainable Development Goal 11 promoted by ONU

Non-spatial skills differ in the front and rear peri-personal space

In measuring behavioural and pupillary responses to auditory oddball stimuli delivered in the front and rear peri-personal space, we find that pupils dilate in response to rare stimuli, both target and distracters. Dilation in response to targets is stronger than the response to distracters, implying a task relevance effect on pupil responses. Crucially, pupil dilation in response to targets is also selectively modulated by the location of sound sources: stronger in the front than in the rear peri-personal space, in spite of matching behavioural performance. This supports the concept that even non-spatial skills, such as the ability to alert in response to behaviourally relevant events, are differentially engaged across subregions of the peri-personal space

Potential Use of MALDI-ToF Mass Spectrometry for Rapid Detection of Antifungal Resistance in the Human Pathogen Candida glabrata.

The echinocandins are relatively new antifungal drugs that represent, together with the older azoles, the recommended and/or preferred agents to treat candidaemia and other forms of invasive candidiasis in human patients. If "time is of the essence" to reduce the mortality for these infections, the administration of appropriate antifungal therapy could be accelerated by the timely reporting of laboratory test results. In this study, we attempted to validate a MALDI-ToF mass spectrometry-based assay for the antifungal susceptibility testing (AFST) of the potentially multidrug-resistant pathogen Candida glabrata against anidulafungin and fluconazole. The practical applicability of the assay, reported here as MS-AFST, was assessed with a panel of clinical isolates that were selected to represent phenotypically and genotypically/molecularly susceptible or resistant strains. The data show the potential of our assay for rapid detection of antifungal resistance, although the MS-AFST assay performed at 3 h of the in vitro antifungal exposure failed to detect C. glabrata isolates with echinocandin resistance-associated FKS2 mutations. However, cell growth kinetics in the presence of anidulafungin revealed important cues about the in vitro fitness of C. glabrata isolates, which may lead to genotypic or phenotypic antifungal testing in clinical practice

New chemiometric technique applied to traceability of Sicilian honey of Sulla (Hedysarum coronarium L.)

The consumers have an increasing interest about food traceability with respect to safety, quality and typicality issues. Food traceability is an important issue in food safety and quality control, with impacts on food security, its quantity and overall availability. Furthermore, the possibility of tracing the origin of foodstuff is assuming an increasingly important role at the legislative level, as a tool that may allow to prove on product authenticity and to control adulteration. So, establish systems to trace food products through specified stages of production, processing and distribution play a key role also to ensure food safety. In the last years, several of analytical techniques have been tested to found ways to establish the geographical origin of different kinds of food and many works reported that the combination of different analytical methods associated a multifactorial analysis of the data seems to be the most promising system to establish univocal traceability systems. The honey is a natural food well appreciated in the world and the detection of potential fraud could be favored through tools linking the chemistry composition of this production to producing area. A small number of investigations regarding traceability of honey can be found in the scientific literature. Therefore, in these contest the development of fingerprinting techniques based on the determination of the specific markers of provenance analyzed whit chemometric approach represents an interesting area of research. Recent works have been demonstrated the potentiality of the study of the distribution patterns of rare earth as a promising analytical method for traceability of food products due coherent and predictable chemical behavior of these compounds. Also, have been demonstrated that their distribution in soil keeps unaltered in plants growing on that soil and eventually in agricultural products obtained from those plants and through the normalization of the REEs distribution, it is possible to appreciate their relative enrichments in soil-plant- agro food products The aim of the research was to observe if the REEs normalizated pattern of honey of Sulla (Hedysarum coronarium L.) was kept unaltered respect the soils of production to establish a correlation between geographic area and honey product. For this study, different production areas of Sulla in Sicily were considered. The production fields explored by the bees within 2 km of the hives were taken into consideration, the soil and the flowering plants were sampled. Flowers and leaves were analyzed from the plant. In the hive, pollen and honey were taken in three different days during the flowering period of the Sulla. Of same areas were sampled to the same methods in different periods where other monofloral honeys were product, these samples were used for a control. In this study the REE approach, give very intriguing results in the geographical traceability of honey samples and are the first. The results have been supported by statistical treatment