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Wireless Personal Communications - Ever since the branching of the sustainable and circular literature on business models of the late 2000s and early 2010´s, academia´s, businesses and...     

Lifetimes of organic photovoltaics: photochemistry, atmosphere effects and barrier layers in ITO-MEHPPV:PCBM-aluminium devices

Large area polymer photovoltaic cells based on poly[(2-methoxy-5-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) were prepared. The lifetimes of the photovoltaic cells were studied in terms of the atmosphere, handling, electrode treatment, mode of preparation and barrier layers by recording the short circuit current as a function of time. Two exponential fits to the decay curves allowed for the extraction of the time constants for different degradation processes. For the periods of time studied here (24–300 h), the decay curves could be fitted with two exponential functions. Common to the preparations were that the first half-life remained short and was independent of the presence of oxygen. When fullerenes were employed by sublimation of a layer of C₆₀ or as the soluble PCBM, the first half-life was an order of magnitude longer and depended on the presence of oxygen. By employing different barrier layers, we found the first half-life to be linked to the aluminium polymer interface and ascribe it to a photochemical reaction between the organic material and the reactive aluminium at the interface. The second and longer half-life was found to depend on the presence of oxygen. We also discuss our findings of the short lifetimes for organic photovoltaics under AM1.5 illumination in the context of future applications.     

Use of honey bees (Apis mellifera L.) to detect the presence of Mediterranean fruit fly (Ceratitis capitata Wiedemann) larvae in Valencia oranges

BACKGROUND: When fruit deteriorates a characteristic profile of volatile chemicals is produced that is different from that produced by healthy fruits. The identification of such chemicals allows the possibility of monitoring the fruit for early signs of deterioration with biological sensors. The use of honey bees and other insects as biological sensors is well known. This study aimed to identify the volatiles produced by oranges infested with larvae of the Mediterranean fruit fly and to test the ability of honey bees, conditioned to this volatile chemical profile, to detect such oranges. RESULTS: Seventeen compounds that were present in higher concentrations in the volatile profiles of infested oranges than in those of insect‐free fruits were mixed at the same relative concentrations as those in the collected volatiles of infested oranges. The synthetic mixture was used to train honey bees by classical Pavlovian conditioning and subsequent tests showed that they were then able to discriminate between medfly‐infested and uninfested oranges. CONCLUSION: This study demonstrates an innovative way of detecting, at an early stage, the symptoms of damage to oranges by the Mediterranean fruit fly. Copyright © 2012 Society of Chemical Industry     

Nanostructured Carbons as Platinum Catalyst Supports for Proton Exchange Membrane Fuel Cell Electrodes

To improve mass transport in the catalytic layers of proton exchange membrane fuel cells, the usual Pt catalyst support (carbon blacks) can be advantageously replaced by carbon aerogels or xerogels. The pore texture of such materials can indeed be tailored, which enables choosing an adequate pore texture minimizing diffusional limitations within the catalytic layers.     

综合技术优势帮助提高生产率和效率

ABB Cellier在为全球造纸行业提供涂料制备服务领域己拥有超过50多年的经验一,这些复杂装置旨在优化化学品的使用,在符合印刷适性和亮度等技术要求的同时提高质量,以便为原纸带来更高的附加值,并改善涂布机的运行性能。     

Microsphere‐Mediated Protein Delivery into Cells

Delivering the goods : By coupling proteins to varyingly sized polymeric microspheres, it is possible to deliver them to cells in an easy and effective way. For this study a fluorescent protein (EGFP) and a functional enzyme (β‐galactosidase) were coupled to these particles. Evaluation of the cellular uptake after “beadfection” shows that the functionality and activity of these proteins were not adversely affected through coupling to the carrier system; this shows that their functional structure is retained.

     

Catalytic study of SOFC electrode materials in engine exhaust gas atmosphere

A single chamber solid oxide fuel cell (SC-SOFC) is a device able to produce electricity from a mixture of hydrocarbons and oxidant. An innovative application of this system would be to recover energy from exhaust gas of a thermal engine. This paper presents a study of stability and catalytic behaviour of electrode materials composing the cell in a mixture of hydrocarbons (propane, propene), oxygen, carbon monoxide, carbon dioxide, hydrogen and water corresponding to a composition of exhaust gas. A screening of four cathode materials was done, some well-known materials in literature and leading to highest performances such as La_0.6Sr_0.4Co_0.2Fe_0.8O_3?δ (LSCF), Sm_0.5Sr_0.5CoO_3?δ and Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3?δ and a last one Pr₂NiO_4+δ (PNO) very promising for conventional SOFCs. Anode material was a cermet composed of nickel and Ce_0.9Gd_0.1O_1.95 which was also selected as the electrolyte material. Chemical stability tests and catalytic activity studies in the gas mixture were performed on the raw materials and have led to a first selection among cathodes. Two hydrocarbons/oxygen ratios (R = HC/O₂) were investigated for materials tests considering the gas mixture stability at high temperature (600 °C): R = 0.21 and 0.44. LSCF and PNO were considered as the most stable cathode materials, besides LSCF demonstrated a lower catalytic activity towards hydrocarbon partial oxidation than PNO especially for the R = 0.44 ratio. As for the anode side, nickel was tested regarding its catalytic activity towards hydrocarbons oxidation. It exhibited catalytic activity towards hydrocarbons partial oxidation, especially for the oxygen-lean ratio (0.44), which gradually decreased while lowering temperature from 620 to 450 °C.     

Prediction of apparent properties with uncertain material parameters using high‐order fictitious domain methods and PGD model reduction

This contribution presents a numerical strategy to evaluate the effective properties of image‐based microstructures in the case of random material properties. The method relies on three points: (1) a high‐order fictitious domain method; (2) an accurate spectral stochastic model; and (3) an efficient model‐reduction method based on the proper generalized decomposition in order to decrease the computational cost introduced by the stochastic model. A feedback procedure is proposed for an automatic estimation of the random effective properties with a given confidence. Numerical verifications highlight the convergence properties of the method for both deterministic and stochastic models. The method is finally applied to a real 3D bone microstructure where the empirical probability density function of the effective behaviour could be obtained. Copyright © 2016 John Wiley & Sons, Ltd.     

Hybrid atomistic�Ccontinuum simulations of fluid flows involving interfaces

In this work, we use an hybrid atomistic–continuum (HAC) simulation method to study transient and steady isothermal flows of Lennard-Jones fluids near interfaces. Our hybrid method is based on a domain decomposition algorithm. The flow domain is composed of two overlapping regions: an atomistic region described by molecular dynamics, and a continuum region described by a finite volume discretization of the incompressible Navier–Stokes equations. To show the interest of such an hybrid method to compute flows near fluid/solid interface, we first applied our hybrid scheme to the classical Couette flow, where the moving wall is modelled at the atomistic scale. In addition, we also studied an oscillatory shear flow. Then, to compute flows near fluid/fluid interface, we applied our method to a two-phase Couette flow (liquid/gas), where the interface is modelled at the molecular scale. We show that hybrid results can sometimes differ from those provided by analytical solutions deduced from continuum mechanics equations combined with usual boundary/interface relations. For the Couette and oscillatory shear flows, a good agreement is found between hybrid simulations and macroscopic analytical solutions, however, we noticed that the fluid in contact with the wall can be more entailed than what expected. For the liquid/gas Couette flow, the hybrid simulation exhibits an unexpected jump of the velocity in the interfacial region, corresponding to a partial slip between the two fluid phases. Those interesting results highlight the interest of using an HAC method to deal with systems for which surfaces/interfaces effects are important.