Photooxygenation of furans in water and ionic liquid solutions

Photooxygenation of differently functionalized furans is investigated in aqueous solutions and in ionic liquids [emim]Br and [bmim]BF4. The reaction is generally selective and the final products derive from rearrangement of the intermediate endoperoxides, depending mainly on the polarity and/or nucleophilic nature of the solvent

Microscopic energy flows in disordered Ising spin systems

An efficient microcanonical dynamics has been recently introduced for Ising spin models embedded in a generic connected graph even in the presence of disorder i.e. with the spin couplings chosen from a random distribution. Such a dynamics allows a coherent definition of local temperatures also when open boundaries are coupled to thermostats, imposing an energy flow. Within this framework, here we introduce a consistent definition for local energy currents and we study their dependence on the disorder. In the linear response regime, when the global gradient between thermostats is small, we also define local conductivities following a Fourier dicretized picture. Then, we work out a linearized "mean-field approximation", where local conductivities are supposed to depend on local couplings and temperatures only. We compare the approximated currents with the exact results of the nonlinear system, showing the reliability range of the mean-field approach, which proves very good at high temperatures and not so efficient in the critical region. In the numerical studies we focus on the disordered cylinder but our results could be extended to an arbitrary, disordered spin model on a generic discrete structures.Comment: 12 pages, 6 figure

Continuum approach to wide shear zones in quasi-static granular matter

Slow and dense granular flows often exhibit narrow shear bands, making them ill-suited for a continuum description. However, smooth granular flows have been shown to occur in specific geometries such as linear shear in the absence of gravity, slow inclined plane flows and, recently, flows in split-bottom Couette geometries. The wide shear regions in these systems should be amenable to a continuum description, and the theoretical challenge lies in finding constitutive relations between the internal stresses and the flow field. We propose a set of testable constitutive assumptions, including rate-independence, and investigate the additional restrictions on the constitutive relations imposed by the flow geometries. The wide shear layers in the highly symmetric linear shear and inclined plane flows are consistent with the simple constitutive assumption that, in analogy with solid friction, the effective-friction coefficient (ratio between shear and normal stresses) is a constant. However, this standard picture of granular flows is shown to be inconsistent with flows in the less symmetric split-bottom geometry - here the effective friction coefficient must vary throughout the shear zone, or else the shear zone localizes. We suggest that a subtle dependence of the effective-friction coefficient on the orientation of the sliding layers with respect to the bulk force is crucial for the understanding of slow granular flows.Comment: 11 pages, 7 figure

Some Experimental Investigations on Gas Turbine Cooling Performed with Infrared Thermography at Federico II

This paper reviews some experimental measurements of convective heat transfer coefficient distributions which are connected with the cooling of gas turbines, performed by the authors' research group at the University of Naples Federico II with infrared thermography. Measurements concern impinging jets, cooling of rotating disks, and gas turbine blades, which are either stationary or rotating. The heated thin foil sensor, associated with the detection of surface temperature by means of infrared thermography, is exploited to accurately measure detailed convective heat transfer coefficient maps. The paper also intends to show how to correctly apply the infrared technique in a variety of gas turbines cooling problems

A hybrid approach of anfis—artificial bee colony algorithm for intelligent modeling and optimization of plasma arc cutting on monel™ 400 alloy

This paper focusses on a hybrid approach based on genetic algorithm (GA) and an adaptive neuro fuzzy inference system (ANFIS) for modeling the correlation between plasma arc cutting (PAC) parameters and the response characteristics of machined Monel 400 alloy sheets. PAC experiments are performed based on box-behnken design methodology by considering cutting speed, gas pressure, arc current, and stand-off distance as input parameters, and surface roughness (Ra), kerf width (kw), and micro hardness (mh) as response characteristics. GA is efficaciously utilized as the training algorithm to optimize the ANFIS parameters. The training, testing errors, and statistical validation parameter results indicated that the ANFIS learned by GA outperforms in the forecasting of PAC responses compared with the results of multiple linear regression models. Besides that, to obtain the optimal combination PAC parameters, multi-response optimization was performed using a trained ANFIS network coupled with an artificial bee colony algorithm (ABC). The superlative responses, such as Ra of 1.5387 µm, kw of 1.2034 mm, and mh of 176.08, are used to forecast the optimum cutting conditions, such as a cutting speed of 2330.39 mm/min, gas pressure of 3.84 bar, arc current of 45 A, and stand-off distance of 2.01 mm, respectively. Furthermore, the ABC predicted results are validated by conducting confirmatory experiments, and it was found that the error between the predicted and the actual results are lower than 6.38%, indicating the adoptability of the proposed ABC in optimizing real-world complex machining processes

Heat Transfer Measurements on a Rotating Disk

Heat transfer to a rotating disk is measured for a wide range of Reynolds number values in the laminar, transitional and turbulent flow regimes. Measurements are performed by making use of the heated-thin-foil technique and by gauging temperature maps with an infrared scanning radiometer. The use of the IR radiometer is advantageous on account of its relatively good spatial resolution and thermal sensitivity and because it allows one to perform measurements down to very low local Reynolds numbers. Data is obtained on three disks, having an external diameter varying from 150mm to 450mm; the smallest disk is used only to measure the adiabatic wall temperature and can rotate up to 21,O00rpm. Heat transfer results are presented in terms of Nusselt and Reynolds numbers based on the local radius and show a substantial agreement with previous experimental and theoretical analyses. Transition to turbulent flow is found at about Re=250,000. A discussion about the role played by the adiabatic wall temperature is also included

Reactions at polymer interfaces: A Monte Carlo Simulation

Reactions at a strongly segregated interface of a symmetric binary polymer blend are investigated via Monte Carlo simulations. End functionalized homopolymers of different species interact at the interface instantaneously and irreversibly to form diblock copolymers. The simulations, in the framework of the bond fluctuation model, determine the time dependence of the copolymer production in the initial and intermediate time regime for small reactant concentration $\rho_0 R_g^3=0.163 ... 0.0406$. The results are compared to recent theories and simulation data of a simple reaction diffusion model. For the reactant concentration accessible in the simulation, no linear growth of the copolymer density is found in the initial regime, and a $\sqrt{t}$-law is observed in the intermediate stage.Comment: to appear in Macromolecule

Intelligent Modeling and Multi-Response Optimization of AWJC on Fiber Intermetallic Laminates through a Hybrid ANFIS-Salp Swarm Algorithm

The attainment of intricate part profiles for composite laminates for end-use applications is one of the tedious tasks carried out through conventional machining processes. Therefore, the present work emphasized hybrid intelligent modeling and multi-response optimization of abrasive waterjet cutting (AWJC) of a novel fiber intermetallic laminate (FIL) fabricated through carbon/aramid fiber, reinforced with varying wt% of reduced graphene oxide (r-GO) filled epoxy resin and Nitinol shape memory alloy as the skin material. The AWJC experiments were performed by varying the wt% of r-GO (0, 1, and 2%), traverse speed (400, 500, and 600 mm/min), waterjet pressure (200, 250, and 300 MPa), and stand-off distance (2, 3, and 4 mm) as the input parameters, whereas kerf taper (Kt) and surface roughness (Ra) were considered as the quality responses. A hybrid approach of a parametric optimized adaptive neuro-fuzzy inference system (ANFIS) was adopted through three different metaheuristic algorithms such as particle swarm optimization, moth flame optimization, and dragonfly optimization. The prediction efficiency of the ANFIS network has been found to be significantly improved through the moth flame optimization algorithms in terms of minimized prediction errors, such as mean absolute percentage error and root mean square error. Further, multi-response optimization has been performed for optimized ANFIS response models through the salp swarm optimization (SSO) algorithm to identify the optimal AWJC parameters. The optimal set of parameters, such as 1.004 wt% of r-GO, 600 mm/min of traverse speed, 214 MPa of waterjet pressure, and 4 mm of stand-off distance, were obtained for improved quality characteristics. Moreover, the confirmation experiment results show that an average prediction error of 3.38% for Kt and 3.77% for Ra, respectively, were obtained for SSO, which demonstrates the prediction capability of the proposed optimization algorithm

Measurements of radioactivity in the environment for radiation protection purposes

Measurements of radioactivity in the environment, according to Article 35 of the Euratom Treaty, are routinely carried out by regulatory bodies and operators in charge. These activities are performed both locally and nationally, in order to assess effective doses to the population. In this context, therefore, it is necessary not only to determine the component due to external irradiation, but also to evaluate the deposit and accumulation of radioactivity in the environment that can reach the public via inhalation or ingestion. The contribution presents a brief description of the aspects regarding programs of monitoring and evaluation of the radioactivity in the environment, in particular the environmental matrices to be monitored, the analyses to be carried out, the related reporting levels as well as the features concerning the influence of the climate on the variations of dose rate values. Finally, a focus on some radiometric measurements performed over the last forty years in the environmental monitoring activities carried out in the ENEA Casaccia Research Center (Rome), in which two nuclear research facilities are currently operating, is presented

The endogenous cannabinoid system in the gut of patients with inflammatory bowel disease

Activation of cannabinoid receptors (CBs) by endocannabinoids impacts on a number of gastrointestinal functions. Recent data indicate that CB1 agonists improve 2,4-dinitrobenzene sulfonic acid-induced colitis in mice, thus suggesting a role for the endocannabinoid agonist anandamide (AEA) in protecting the gut against inflammation. We here examined the gut endocannabinoid system in inflammatory bowel disease (IBD) patients, and investigated the ex vivo and in vitro effects of the non-hydrolysable AEA analog methanandamide (MAEA) on the mucosal proinflammatory response. The content of AEA, but not of 2-arachidonoyl-glycerol and N-palmitoylethanolamine, was significantly lower in inflamed than uninflamed IBD mucosa, and this was paralleled by lower activity of the AEA-synthesizing enzyme N-acyl-phosphatidylethanolamine-specific phospholipase D and higher activity of the AEA-degrading enzyme fatty acid amide hydrolase. MAEA significantly downregulated interferon-γ and tumor necrosis factor-α secretion by both organ culture biopsies and lamina propria mononuclear cells. Although these results are promising, further studies are needed to determine the role of cannabinoid pathways in gut inflammation. © 2011 Society for Mucosal Immunology