Sensitive detection of salbutamol using europium-enhanced fluorescence with trioctylphosphine oxide (TOPO) as coligand

In this work a simple and sensitive fluorimetric method for determination of salbutamol (4-[2-(tert-butylamino)-1-hydroxyethyl]-2-(hydroxymethyl) phenol) using an Eu enhanced signal was developed. The employed methodology is based on the formation of a ternary complex formed with Eu, salbutamol and trioctylphosphine oxide (TOPO). Intermolecular transfer of energy from the excited organic molecule to the lanthanide followed by lanthanide emission is responsible for excitation of the lanthanide ion in complex solutions and fluorescent enhancement. The luminescence properties of the ternary complex formed with TOPO and optimum formation conditions were investigated. The calibration curve is linear in the range between 6.92-180 microg l(-1) of salbutamol. The detection limit was 2.31 microg l(-1). Common excipients for these formulations were not found to interfere. A proposed method for the assay in commercial aerosols and nebulizer solutions containing salbutamol was applied with very good precision.     

Energy spectra of atoms sputtered by KeV light-ion bombardment

A calculation has been made for the sputtering of heavy targets by KeV light-ion bombardment. The calculation is based both on linear transport theory and on the assumption that only primary recoiling atoms are candidates for the sputtering process. The energy spectra calculation predicts the experimentally observed peak shift towards lower velocities than those obtained by standard linear cascade theory.     

After effects of orbital electron capture in Co spinels

In this work we present several Mössbauer emission spectra of the spinels ⁵⁷CoMn₂O₄, ⁵⁷CoY₂O₄ and ⁵⁷CoV₂O₄ prepared under well determined conditions. The consequences of electronic capture in ⁵⁷Co in spinels are studied. It is found that the appearance of anomalous charge states is connected with the macroscopic properties of the spinel.     

An existence theorem for Lagrange problems in Banach spaces

We give an existence theorem for a Lagrange problem in a reflexive separable Banach space. We prove the main theorem by means of the direct method of the calculus of variations introduced by Tonelli.This work has been supported by the Laboratorio per la Matematica Applicata, Consiglio Nazionale delle Ricerche, Genova, Italy.The authors wish to thank Professor J. P. Cecconi who has drawn their attention to these problems.     

Quaternized Pyridyloxy Phthalocyanines Render Aqueous Electron‐Donor Carbon Nanotubes as Unprecedented Supramolecular Materials for Energy Conversion

Exploring new properties in known materials, sometimes even achieving behaviors opposite to those traditionally encountered, is a fundamental aspect of innovation in materials science. In the field of energy conversion, for example, the development of water‐processed organic solar cells provides environmentally friendlier materials, which contribute to reduce health risks. Herein, a novel approach is described to produce water‐soluble electron‐donor single wall carbon nanotube (SWCNT) hybrids based on the noncovalent immobilization of quaternized pyridyloxy zinc phthalocyanines (ZnPc) with a varying number of pyridyl substituents. Moreover, the excellent electron‐accepting ability of the latter ZnPcs is reported. The introduction of tert‐butylphenyl groups at the pyridines enables for the first time a complete characterization. The electron‐acceptor nature of the ZnPcs enables switching the role of SWCNTs within the resulting supramolecular hybrids. Finally, a proof‐of‐concept demonstration of the SWCNT/ZnPc hybrids' capacity for energy conversion is presented, paving their way to possible use as active layer material in solar cells processed entirely from aqueous solutions.     

Wafer bonded four‐junction GaInP/GaAs//GaInAsP/GaInAs concentrator solar cells with 44.7% efficiency

Triple‐junction solar cells from III–V compound semiconductors have thus far delivered the highest solar‐electric conversion efficiencies. Increasing the number of junctions generally offers the potential to reach even higher efficiencies, but material quality and the choice of bandgap energies turn out to be even more importance than the number of junctions. Several four‐junction solar cell architectures with optimum bandgap combination are found for lattice‐mismatched III–V semiconductors as high bandgap materials predominantly possess smaller lattice constant than low bandgap materials. Direct wafer bonding offers a new opportunity to combine such mismatched materials through a permanent, electrically conductive and optically transparent interface. In this work, a GaAs‐based top tandem solar cell structure was bonded to an InP‐based bottom tandem cell with a difference in lattice constant of 3.7%. The result is a GaInP/GaAs//GaInAsP/GaInAs four‐junction solar cell with a new record efficiency of 44.7% at 297‐times concentration of the AM1.5d (ASTM G173‐03) spectrum. This work demonstrates a successful pathway for reaching highest conversion efficiencies with III–V multi‐junction solar cells having four and in the future even more junctions. Copyright © 2014 John Wiley & Sons, Ltd.     

Value of net‐FiT PV policies for different electricity industry participants considering demand‐side response

Net‐metering feed‐in‐tariffs (net‐FiT) policies for residential photovoltaics (PV) have financial implications not only for PV customers but also for all other electricity industry participants. They may also incentivise households to adjust their daily load patterns to either minimise or maximise PV export depending on the FiT design and wider retail electricity arrangements. In this paper, we study the financial implications of both residential PV systems and such demand‐side response (DSR) on the financial returns of PV for households, their retailers and their distribution network service providers (DNSPs). We use half‐hourly PV generation and household consumption data for 61 houses in the Australian city of Sydney and consider two net‐FiT designs offering tariffs either significantly higher or lower than retail electricity rates. We use a simple model of DSR that allows households to increase PV exports or self‐consumption by moving load between daylight hours and the evening. We find that such DSR modestly improve household revenue but has potentially greater implications for retailers and DNSPs. DSR to increase exports reduces the adverse impacts of PV on retailer and DNSP revenues, while increased self‐consumption worsens them. Conversely, increased exports might drive DNSP expenditures in constrained network areas while increased self‐consumption might help reduce them. The study highlights the importance of designing PV policies with regard to their implications for retailers and DNSPs as well as PV households. Furthermore, the broader policy settings of retail electricity markets will become increasingly important as PV deployment grows, opportunities for DSR expand and current inadequacies in retail electricity markets become more marked. Copyright © 2014 John Wiley & Sons, Ltd.     

Estimating retail demand with Poisson mixtures and out‐of‐sample likelihood

Estimation of retail demand is critical to decisions about procuring, shipping, and shelving. The idea of Poisson demand process is central to retail inventory management and numerous studies suggest that negative binomial (NB) distribution characterize retail demand well. In this study, we reassess the adequacy of estimating retail demand with the NB distribution. We propose two Poisson mixtures—the Poisson–Tweedie family (PTF) and the Conway–Maxwell–Poisson distribution—as generic alternatives to the NB distribution. On the basis of the principle of likelihood and information theory, we adopt out‐of‐sample likelihood as a metric for model selection. We test the procedure on consumer demand for 580 stock‐keeping unit store sales datasets. Overall the PTF and the Conway–Maxwell–Poisson distribution outperform the NB distribution for 70% of the tested samples. As a general case of the NB model, the PTF has particularly strong performance for datasets with relatively small means and high dispersion. Our finding carries useful implications for researchers and practitioners who seek for flexible alternatives to the oft‐used NB distribution in characterizing retail demand. Copyright © 2013 John Wiley & Sons, Ltd.     

IP Flow Mobility in PMIPv6 Based Networks: Solution Design and Experimental Evaluation

The ability of offloading selected IP data traffic from 3G to WLAN access networks is considered a key feature in the upcoming 3GPP specifications, being the main goal to alleviate data congestion in cellular networks while delivering a positive user experience. Lately, the 3GPP has adopted solutions that enable mobility of IP-based wireless devices relocating mobility functions from the terminal to the network. To this end, the IETF has standardized Proxy Mobile IPv6 (PMIPv6), a protocol capable to hide often complex mobility procedures from the mobile devices. This paper, in line with the mentioned offload requirement, further extends PMIPv6 to support dynamic IP flow mobility management across access wireless networks according to operator policies. Considering energy consumption as a critical aspect for hand-held devices and smart-phones, we assess the feasibility of the proposed solution and provide an experimental analysis showing the cost (in terms of energy consumption) of simultaneous packet transmission/reception using multiple network interfaces. The end-to-end system design has been implemented and validated by means of an experimental network setup.     

Dissipation of insect growth regulators in fresh and canned fruits

The objective of the study was to determine the dissipation of insect growth regulators in fresh and canned mandarin and apricot to determine the exposure to them. Field studies were carried out in the preharvest period with good agricultural practices (GAP) and in critical agricultural practices. The processing studies were carried out in each relevant step in a pilot plant. A validated methodology was developed (limit of quantification of 0.05?mg?kg^?1 for apricots, 0.10?mg?kg^?1 for mandarin) including acetone–dichloromethane extraction, cleanup, and liquid chromatography-diode array detection. The pesticides complied with the maximum residue limits (MRLs) except pyriproxyfen, which has not been authorized in apricots, and it did not comply with its MRL for peaches. The dissipation rates (t _1/2) with GAP were fenoxycarb-apricot?>?pyriproxyfen-apricot?>?fenoxycarb-mandarin?>?pyriproxyfen-mandarin. In the processing studies, there was only residue transference in the canning of apricots. All final cans contained residues much lower than the MRLs.