Thermal Model in ANSYS for a Comparison Between two Configurations of a Concentrating Photovoltaic System

The theoretical analysis of different concentrating photovoltaic and thermal systems (CPV/T) is presented in this paper; it allows to evaluate the cooling fluid temperature in different working conditions. In particular, two CPV/T systems with different optics, line-focus and point-focus, are studied and compared theoretically by means of a model developed in ANSYS-CFX able to evaluate the theoretical temperature values of the fluid that flows in the cooling circuit, designed with the Solidworks software. The comparison in terms of the thermal performances between the point-focus and line-focus configurations of a CPV/T system has been realized considering different working conditions. As model input the uniform cell temperature has been set to different values, included between 323 K and 363 K, or determined experimentally referring to the point-focus configuration. In particular, the outlet temperatures of the cooling fluid, the fluid and cells temperatures difference at the outlet section, the time necessary to reach a steady-state condition, the fluid temperature trend in different parts of the tube and along the circuit, have been evaluated. Moreover, the fluid temperature trend has been studied varying the fluid velocity, its mass flow rate, and the insulation thickness. Finally, the point-focus CPV/T system thermal performances have been also evaluated adopting some experimental measurements as input data; the fluid temperature trend has been tested under a variable cell temperature during different hours of a sunny and a cloudy day.     

Organic Small Molecules for Photonics and Electronics from the [2.2]Paracyclophane Scaffold

In the search for molecules for organic photonics and electronics, several strategies have been used to modulate physical and chemical properties of [2.2]paracyclophane derivatives by sequential functionalization of their three-dimensional cores. This review summarizes the major design and synthetic strategies for tuning paracyclophane-containing small molecules by introducing various moieties featuring (hetero)aromatic rings directly connected to each other, as well as alternating (hetero)aryl and ethylene or ethynylene units. Several examples are presented that elucidate the structural, optical, and electronic consequences of incorporating these fragments in the aromatic decks, particularly relating to applications in organic optoelectronics.     

Oxidase Reactivity of CuII Bound to N-Truncated Aβ Peptides Promoted by Dopamine

The redox chemistry of copper(II) is strongly modulated by the coordination to amyloid-β peptides and by the stability of the resulting complexes. Amino-terminal copper and nickel binding motifs (ATCUN) identified in truncated Aβ sequences starting with Phe4 show very high affinity for copper(II) ions. Herein, we study the oxidase activity of [Cu–Aβ_4−x] and [Cu–Aβ_1−x] complexes toward dopamine and other catechols. The results show that the Cu^II–ATCUN site is not redox-inert; the reduction of the metal is induced by coordination of catechol to the metal and occurs through an inner sphere reaction. The generation of a ternary [Cu^II–Aβ–catechol] species determines the efficiency of the oxidation, although the reaction rate is ruled by reoxidation of the Cu^I complex. In addition to the N-terminal coordination site, the two vicinal histidines, His13 and His14, provide a second Cu-binding motif. Catechol oxidation studies together with structural insight from the mixed dinuclear complexes Ni/Cu–Aβ_4−x reveal that the His-tandem is able to bind Cu^II ions independently of the ATCUN site, but the N-terminal metal complexation reduces the conformational mobility of the peptide chain, preventing the binding and oxidative reactivity toward catechol of Cu^II bound to the secondary site.     

Osteoporosis in Men: A Review of an Underestimated Bone Condition

Osteoporosis is called the ‘silent disease’ because, although it does not give significant symptoms when it is not complicated, can cause fragility fractures, with serious consequences and death. Furthermore, the consequences of osteoporosis have been calculated to weigh heavily on the costs of health systems in all the countries. Osteoporosis is considered a female disease. Actually, the hormonal changes that occur after menopause certainly determine a significant increase in osteoporosis and the risk of fractures in women. However, while there is no doubt that women are more exposed to osteoporosis and fragility fractures, the literature clearly indicates that physicians tend to underestimate the osteoporosis in men. The review of the literature done by the authors shows that osteoporosis and fragility fractures have a high incidence also in men; and, furthermore, the risk of fatal complications in hip fractured men is higher than that for women. The authors report the evidence of the literature on male osteoporosis, dwelling on epidemiology, causes of osteoporosis in men, diagnosis, and treatment. The analysis of the literature shows that male osteoporosis is underscreened, underdiagnosed, and undertreated, both in primary and secondary prevention of fragility fractures.     

Assessment of high performance SAPO-34/S-PEEK composite coatings for adsorption heat pumps

In this work, a new composite adsorbent coating on aluminum support, based on SAPO34 zeolite filler embedded into sulfonate polyether ether ketone matrix is investigated for adsorption heat pumps (AHP) applications. Composite zeolite/polymer mixtures, with 80–95 wt% content of SAPO-34 zeolite filler have been prepared and coated on aluminum substrates. The as prepared coatings showed a pull-off adhesion strength up to 2.0 MPa, significantly higher than conventional values of composite zeolite coatings reported in the literature. Scanning electron microscopy analysis demonstrated that the coating has a homogeneous morphology with zeolite filler well interconnected in the composite coating structure. Water adsorption isobars were carried out at equilibrium in the temperature range 30–120°C. The best adsorption performances for AHPs applications were observed for the PZ-95 batch, where a maximum water uptake of ∼29.0 wt% was reached, highlighting that the polymer matrix presence does not alter the zeolite adsorption capability (31.3 wt%).     

Capturing the footprints of ground motion in the spatial distribution of rainfall-induced landslides

Bulletin of Engineering Geology and the Environment - The coupled effect of earthquakes and rainfall is rarely investigated in landslide susceptibility assessments although it could be crucial to...     

Evaluation of smectite clays as nanofillers for the synthesis of nanocomposite polymer electrolytes for fuel cell applications

Synthetic and natural smectite clays, with different structural and physical parameters, were tested as nanofillers for the creation of Nafion nanocomposites. The solution intercalation method has been successfully applied for incorporation of layered materials into the polymer, while the effect of the solvent, temperature and filler loading were examined in order to determine the optimum conditions for the preparation of highly homogeneous composites.     

A polymeric micro-optical system for the spatial monitoring in two-phase microfluidics

This article presents a polymeric micro-optical system that consists of two coupled miniaturized devices for spatially distributed characterization of microfluidic two-phase phenomena exploiting multiwavelength optical signals. The input device implements four optical windows (slits) which are superimposed on the centerline of a microfluidic serpentine channel and illuminate specific locations of the microchannel. The flow-related information is then collected by an ad hoc polymeric micro-optical output device that guides and merges the spatially distributed information into a single output signal, which maintains memory of the spatial coordinates by using the wavelengths as fingerprints of the slits’ position in the microfluidic channel. Both micro-optical devices were designed, simulated, and characterized in static and dynamic conditions. Experiments on two-phase (air and ethanol) flow were carried out by applying constant and periodic flow rate functions. In both cases, the system was proved to be efficient in capturing the spatial–temporal dynamics of flow profiles.     

A dynamic Bayesian network based framework to evaluate cascading effects in a power grid

In recent years, the growing interest toward complex critical infrastructures and their interdependencies have solicited new efforts in the area of modeling and analysis of large interdependent systems. Cascading effects are a typical phenomenon of dependencies of components inside a system or among systems. The present paper deals with the modeling of cascading effects in a power grid. In particular, we propose to model such effects in the form of dynamic Bayesian networks (DBN) which can be derived by means of specific rules, from the power grid structure expressed in terms of series and parallel modules. In contrast with the available techniques, DBN offer a good trade-off between the analytical tractability and the representation of the propagation of the cascading event. A case study taken from the literature, is considered as running example.     

Data-driven communication for state estimation with sensor networks

This paper deals with the problem of estimating the state of a discrete-time linear stochastic dynamical system on the basis of data collected from multiple sensors subject to a limitation on the communication rate from the sensors. More specifically, the attention is devoted to a centralized sensor network consisting of: (1) multiple remote nodes which collect measurements of the given system, compute state estimates at the full measurement rate and transmit data (either raw measurements or estimates) at a reduced communication rate; (2) a fusion node that, based on received data, provides an estimate of the system state at the full rate. Local data-driven transmission strategies are considered and issues related to the stability and performance of such strategies are investigated. Simulation results confirm the effectiveness of the proposed strategies.