Heteroatom Effect on Star‐Shaped Hole‐Transporting Materials for Perovskite Solar Cells

Three new star‐shaped hole‐transporting materials (HTMs) incorporating benzotripyrrole, benzotrifuran, and benzotriselenophene central cores endowed with three‐armed triphenylamine moieties ( BTP‐1 , BTF‐1 , and BTSe‐1 , respectively) are designed, synthesized, and implemented in perovskite solar cells (PSCs). The impact that the heteroatom‐containing central scaffold has on the electrochemical and photophysical properties, as well as on the photovoltaic performance, is systematically investigated and compared with their sulfur‐rich analogue ( BTT‐3 ). The new HTMs exhibit suitable highest‐occupied molecular orbitals (HOMO) levels regarding the valence band of the perovskite, which ensure efficient hole extraction at the perovskite/HTM interface. The molecular structures of BTF‐1 , BTT‐3 , and BTSe‐1 are fully elucidated by single‐crystal X‐ray crystallography as toluene solvates. The optimized (FAPbI₃)_0.85(MAPbBr₃)_0.15‐based perovskite solar cells employing the tailor‐made, chalcogenide‐based HTMs exhibit remarkable power conversion efficiencies up to 18.5%, which are comparable to the devices based on the benchmark spiro‐OMeTAD. PSCs with BTP‐1 exhibit a more limited power conversion efficiency of 15.5%, with noticeable hysteresis. This systematic study indicates that chalcogenide‐based derivatives are promising HTM candidates to compete efficiently with spiro‐OMeTAD.     

Interaction of specialized cardiac conduction system with antiarrhythmic drugs: a simulation study

The use of antiarrhythmic drugs is common to treat heart rhythm disorders. Computational modeling and simulation are promising tools that could be used to investigate the effects of specific drugs on cardiac electrophysiology. In this paper, we study the multiscale effects of dofetilide, a drug that blocks IKr, from cellular to organ level paying special attention to its effect on heart structures, in particular the specialized cardiac conduction system (CCS). We include a model of the CCS in a patient-specific anatomical ventricular model and study the drug effects in simulations with and without a CCS. Results confirmed the expected effects of dofetilide at cellular level, increasing the action potential duration, and at organ level, prolonging the QT segment. Notable differences are shown between models with and without the CCS on action potential duration distributions. These techniques show the importance of heart heterogeneity and the global effects of the interaction of drugs with cardiac structures.     

A CAD-oriented method to analyze and design radiating structures based on bodies of revolution by using finite elements and generalized scattering matrix

In this work, an efficient analysis of radiating structures based on bodies of revolution is dealt with. The procedure is a hybrid method based on a segmentation of the structure into two-dimensional regions, finite elements and a spherical computation domain surrounding the antenna, defining a boundary or port where a spherical mode expansion of the fields is used. A reduced order model is computed for a fast frequency sweep. To validate this method, some structures based on bodies of revolution as a rod dielectric antenna, conical dielectric-loaded horns, profiled horns and a monopole-dielectric resonator antenna are studied and results are compared with those demonstrated by other authors. The design of a smooth-walled horn by means of the optimization of the profile is also carried out.     

Effect of natural fermentation on the content of inositol phosphates in lentils

The effects of natural fermentation upon phytic acid and less phosphorylated inositol phosphates ofLens culinaris var vulgaris cultivar Magda-20 were investigated. Seven fermentation runs were made following a 2² complete factorial design with three replicated centre points to study the effect of different conditions of temperature (28, 35 and 42°C) and broth concentration (79, 150 and 221 g/l). Samples were taken for each of them at daily intervals (0, 24, 48, 72 and 96 h). The pH value declined sharply in the first 24 h of fermentation, becoming stabilized from this time. The relation between lactic acid and titratable acidity presented important differences between the different fermentations, ranging from 30–80%. Phytic acid (IP ₆), inositol pentakis (IP ₅), tetrakis (IP ₄) and tris-(IP ₃) phosphates were quantitatively determined. The content of total inositol phosphates showed a maximum reduction of 63% at 72 h under the fermentation conditions of 42°C and 79 g/l.     

Effect of heating temperature and sodium chloride concentration on ultrastructure and texture of gels made from giant squid (Dosidicus gigas) with addition of starch,l-carrageenan and egg white

This paper seeks to compare the ultrastructure of gels made from frozen muscle of giant squid (Dosidicus gigas) at various temperatures with a number of different rheological parameters, with reference to a variety of added ingredients (non-muscle proteins and hydrocolloids) and to NaCl concentration. Interesting data on gel rheological properties were found where formulae containedl-carrageenan, starch and egg white, with a low salt concentration (1.5%). This seems to be because carrageenan forms an independent network which supports the principal structure formed by the fish protein; starch is incorporated into the network and retains water; and egg white forms a supplementary network which helps to improve rheological properties.     

A Parallel Hill Climbing Algorithm for Pushing Dependent Data in Clients–Providers–Servers Systems

The up-link bandwidth in satellite networks and in advanced traffic wireless information system is very limited. A server broadcasts data files provided by different independent providers and accessed by many clients in a round-robin manner. The clients who access these files may have different patterns of access. Some clients may wish to access several files in any order (AND), some wish to access one out of several files (OR), and some clients may access a second file only after accessing another file (IMPLY). The goal of the server is to order the files in a way that minimizes the access time of the clients given some a priori knowledge of their access patterns. An appropriate clients–servers model was recently proposed by Bay-Noy, Naor and Schieber. They formulated three separate problems and proposed an algorithm that evaluates certain number of random permutations and chooses the one whose access time is minimized. In this paper, we formulate a combined AOI (AND-OR-IMPLY) problem, and propose to apply a parallel hill climbing algorithm (to each of the four problems), which begins from certain number of random permutations, and then applies hill climbing technique on each of them until there is no more improvement. The evaluation time of neighboring permutations generated in hill climbing process is optimized, so that it requires O(n) time per permutation instead of O(n ²) time required for evaluating access time of a random permutation, where n is the number of files the server broadcasts. Experiments indicate that the parallel hill climbing algorithm is O(n) times faster that random permutations method, both in terms of time needed to evaluate the same number of permutations, and time needed to provide a high quality solution. Thus the improvement is significant for broadcasting large number of files.     

Solar irradiation and PV module temperature dispersion at a large‐scale PV plant

When evaluating the performance of a photovoltaic (PV) system, it is extremely important to correctly measure the plant operating conditions: incident irradiation and cell temperature. At large‐size PV plants, the possible dispersion of the plant operating conditions may affect the representativeness of the values measured at one single point. The available literature contains many observations on irradiance dispersion (typically associated to high temporal resolution experiments) and its effects on the PV power output (unexpected power transients, power fluctuations, etc.). However no studies have been made on the long‐term energy‐related effects of geographic dispersion of solar irradiation, which could affect, for example, to the uncertainty in determining energy performance indexes like PR. This paper analyses the geographical dispersion in the PV operating conditions observed at low temporal resolutions (day, month and year) at two PV plants located, respectively, in the south of Portugal and the north of Spain. It shows that daily irradiation deviations are significantly higher than is commonly supposed. Furthermore, once the measurement points are a certain distance apart (a few hundred metres), the deviations in irradiation appear to be independent of distance. This could help to determine how many irradiance sensors to install in order to reduce uncertainty. Daily mean temperature differences between different points at a large‐scale PV plant range from 1 to 7 K and are not related to the distance between measurement points. Copyright © 2014 John Wiley & Sons, Ltd.     

Nanoconfined (Bio)Catalysts as Efficient Glucose‐Responsive Nanoreactors

Herein, the design, synthesis, and characterization of bifunctional hybrid nanoreactors used for concurrent one‐pot chemoenzymatic reactions are shown. In the design, the enzyme, glucose oxidase, is wrapped with a peroxidase‐mimetic catalytic polymer. Hemin, the organic catalyst, is linked to the flexible polymeric scaffold through coordination to the imidazole groups that hang out the network. This spatial arrangement, which works as a metabolic channel, is optimized for cooperative chemoenzymatic reactions in which the enzyme catalyzes first. A deep characterization of the integrated nanoreactors demonstrates that the confinement of two distinct catalytic sites in the nanospace is very effective in one‐pot reactions. Moreover, besides its role as scaffold material, the polymeric mantel protects both the biocatalyst and the chemical catalyst from degradation and inactivation in the presence of organic solvents. Furthermore, the polymeric environment of the nanoreactors can be tailored in order to trigger the assembly of those into highly active heterogeneous hybrid catalysts. Finally, the new nanoreactors are applied to the efficient degradation of organic aromatic compounds using glucose as the only fuel.     

Power output fluctuations in large scale pv plants: One year observations with one second resolution and a derived analytic model

The variable nature of the irradiance can produce significant fluctuations in the power generated by large grid‐connected photovoltaic (PV) plants. Experimental 1 s data were collected throughout a year from six PV plants, 18 MWp in total. Then, the dependence of short (below 10 min) power fluctuation on PV plant size has been investigated. The analysis focuses on the study of fluctuation frequency as well as the maximum fluctuation value registered. An analytic model able to describe the frequency of a given fluctuation for a certain day is proposed. Copyright © 2010 John Wiley & Sons, Ltd.     

Spin-Crossover Grafted Monolayer of a Co(II) Terpyridine Derivative Functionalized with Carboxylic Acid Groups

The synthesis and characterization of a new Co(II) spin-crossover (SCO) complex based on 4′-(4-carboxyphenyl)−2,2′:6′,2″-terpyridine ligand are reported. This complex can be successfully grafted on silver surface maintaining the SCO behavior. Thus, atomic force microscopy (AFM), matrix assisted laser desorption ionization – time-of-flight mass spectrometry (MALDI-TOF MS), Raman spectroscopy, and XPS measurements, upon surface deposition, evidence the formation of a monolayer of intact molecules grafted through carboxylate groups to the Ag surface. Three different techniques: Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS), supported by first-principles calculations, confirm that the deposited molecules undergo a gradual spin transition with temperature. This phenomenon is unprecedented for a monolayer of molecules directly grafted onto a metallic surface from solution.