On the problem of the elastic plate on one-sided foundation

Summary Solution existence, uniqueness and regularity are analyzed for the elastic plate on unilateral elastic foundation problem. Some results are also given for the one-sided rigid foundation case.

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Sommario Si studiano l'esistenza, l'unicità e la regolarità delle soluzioni del problema della piastra elastica su fondazione elastica unilaterale. Sono anche dati alcuni risultati per il caso di fondazione rigida unilaterale.

     

Real-time algorithm,based on two extra sensors,for monitoring platform’s orientation of underactuated parallel wrists

The direct position analysis of parallel manipulators (PMs) brings to determine a finite number of platform poses compatible with an assigned set of actuated-joint variables’ values. Therefore, when, during functioning, the need to check the actual platform pose arises, the sensors usually located on the actuators are not sufficient and the additional pieces of information coming from ad-hoc-devised extra sensors are necessary. Here, for the first time, the actual implementation of extra sensors in underactuated parallel wrists (PWs) which contain a nonholonomic constraint is addressed. Differently from “ordinary” (i.e., non-underactuated) PWs, these PWs requires a continuous monitoring of the actual platform orientation to compensate the possible sliding in the nonholonomic constraint. Thus, in this case, the algorithms that interpret the pieces of information coming from the sensors must work in real time and must be integrated in the control software that manages the motion of the machine. All these special requirements are satisfied by the proposed algorithm. Moreover, the proposed hardware can also be implemented in some ordinary PWs with a cheap add-on kit.     

Modeling Unsaturated Flow in Absorbent Swelling Porous Media: Part 1. Theory

The flow and deformation processes in swelling porous media are modeled for absorbent hygiene products (e.g., diapers, wipes, papers etc.). The first part of the article derives the fundamental equations for the hysteretic unsaturated flow, liquid absorption, and large deformation. The final set of model equations consists of balance equations of mobile and absorbed (immobile) liquid combined with a series of constitutive relationships. The resulting equation system is strongly nonlinear and requires advanced numerical strategies for solving. The second part of the article focuses on numerical solution and presents simulation results for 2D and 3D applications.     

Effect of Salt Addition and Fermentation Time on Phenolics,Microbial Dynamics,Volatile Organic Compounds,and Sensory Properties of the PDO Table Olives of Gaeta (Italy)

‘Oliva di Gaeta’ is almost certainly the most important and well-known PDO denomination for table olives in Italy. Their production is based on a specific two-stage trade preparation called the ‘Itrana’ method. In this work, we investigated how variations in the duration of the initial water fermentation (i.e., 15 and 30 days) and the salt concentration (i.e., 6% and 8% NaCl) influence the chemical features, microbial dynamics, polyphenols, volatile organic compounds, and sensory features of ‘Oliva di Gaeta’. The time of the addition of salt did not affect the final concentration in the brine, but a longer initial water fermentation (before salt addition) led to lower pH values. The bacterial count constantly increased until the salt addition (i.e., either 15 or 30 days), while the yeast population peaked on day 30. Generally, the two different salt concentrations did not affect the count of microorganisms at the end of fermentation, with the only exception being a higher lactic acid bacteria count for the treatment with 6% salt added at 30 days. At commercial maturity, the crucial bitter tastant oleuropein was not completely removed from the drupes, and differences in salt concentration and the length of the first-stage water fermentation did not influence its content at the end of olive curing. Richer volatile profiles of olives were detected with higher-salt treatments, while the combination of low salt and early saline treatment provided a more distinct profile. Longer initial water fermentation caused a small increase in some phenolic compounds (e.g., iso-verbascoside, verbascoside, and hydroxytyrosol-glucoside). A panel test indicated that salt application at 30 days resulted in a more “Sour” and “Bitter” taste, irrespective of the salt concentration. The low salt concentration coupled with the late saline treatment resulted in more “Fruity” notes, probably due to the higher production of esters by lactobacilli. The slightly bitter perception of the olives was consistent with the partial removal of oleuropein. Our work revealed the characteristics of the ‘Itrana’ method and that the variation in salt concentration and its time of application changes parameters ranging from the microbial dynamics to the sensory profile. Specifically, our data indicate that 6% NaCl coupled with a longer initial water fermentation is the most different condition: it is less effective in blocking microbial growth but, at the same time, is more potent in altering the nutritional (e.g., polyphenols) and sensorial qualities (e.g., bitterness and fruitiness) of ‘Oliva di Gaeta’.     

Synthesis,Docking Studies and Pharmacological Evaluation of Serotoninergic Ligands Containing a 5-Norbornene-2-Carboxamide Nucleus

A new series of 5-norbornene-2-carboxamide derivatives was prepared and their affinities to the 5-HT_1A, 5-HT_2A, and 5-HT_2C receptors were evaluated and compared to a previously synthesized series of derivatives characterized by exo-N-hydroxy-5-norbornene-2,3-dicarboximidenucleus, in order to identify selective ligands for the above-mentioned subtype receptors. Arylpiperazines represents one of the most important classes of 5-HT_1AR ligands, and recent research concerning new derivatives has been focused on the modification of one or more portions of such pharmacophore. The combination of structural elements (heterocyclic nucleus, propyl chain and 4-substituted piperazine), known to be critical to the affinity to 5-HT_1A receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that Norbo-4 and Norbo-18 were the most active and promising derivatives for the serotonin receptor considered in this study.     

Zur Steigerung der Empfindlichkeit der Salpeters?urereaction mit Diphenylamin bei Wasseruntersuchungen

Ohne Zusammenfassung     

Do computed crystal structures of nonpolar molecules depend on the electrostatic interactions? The case of tetracene

We present a strategy for comparing the global properties of competing potential models. By systematically sampling the potential energy surface of crystalline tetracene, we assess how the number, energy and structure of its minima are modified by switching on (or off) the Coulombic interactions. The increased complexity of the Coulombic potential leads to a more "rugged" potential energy surface with a larger number of minima, but the effect is not large. In fact, we find a subset of minima stable only in presence of the Coulombic interactions, a smaller subset stable only in their absence, and a large majority stable in both cases. Among these, there is a very good, but not perfect, correlation between the energies and the structures computed with and without the electrostatic interactions. Although electrostatic interactions play a role even in a rigid nonpolar molecule such as tetracene, they are not as crucial as often believed, because altering the electrostatic model (or switching it off completely) leads, in most cases, to equivalent results.     

Ab initio calculation of some low-lying electronic excited states of methane

The energies of some low-lying electronic excited states of methane are calculated by using wave functions built up in terms of plane waves modulated by multicenter Gaussian factors. The wave functions of the various states are evaluated by a two steps iterative process. In the first step, each excited orbital is determined while keeping all other rigid; in the second, rearrangement effects are introduced. Final results are in good agreement with experimental data and allow to enhance an assignement hypothesis for the first electronic transitions.     

Amplified spontaneous emission in dye-laser systems for single photon amplification

A longitudinally pumped dye-laser amplifier is numerically investigated for the amplification of a very low intensity signal (as low as one photon per pulse), which is easily hindered by the simultaneous amplification of spontaneous emission. From the relevant set of coupled rate equations for population and photon fluxes the spatial dependence of these quantities is accounted for. The equations are solved numerically in some significant practical situations. The results describe the dependence of the amplified-spontaneous-emission (ASE) output flux on the pumping rate, on the spectral narrowing process and on the total spontaneous emission for a pulse in the selected angular width. The performance of dye-laser amplifiers is described by the same set of equations, and the gain characteristics of such systems are analyzed as functions of the pumping rate.