Comparison of AFM and HRTEM to determine the metal particle morphology and loading of an Au/TiO2 catalyst

Atomic force microscopy (AFM) has been used to study the morphology of an ultrafine gold‐on‐titania catalyst. By using TappingMode^TM AFM (TMAFM) and SuperSharp silicon probes to minimize tip radius artifacts, we determined values for the average Au particle diameter and the gold loading in good agreement with high‐resolution transmission electron microscopy (HRTEM) results. These results demonstrate the ability of AFM to characterize real supported metal catalysts with small metal particles (<5 nm) and low metal loadings, achieving resolution comparable to HRTEM, but in the ambient environment. This revised version was published online in July 2006 with corrections to the Cover Date.     

Liquid-feed flame spray pyrolysis derived nanopowders (NPs) as a route to electrically conducting calcium aluminate (12CaO.7Al2O3) films

Traditionally, C12A7 materials have been processed via solid-state reaction followed by pulsed laser deposition (PLD) or floating zone (Fz) crystallization methods at high temperature, high cost approaches to single-phase films. These techniques require a significant number of process steps to generate C12A7:e^? materials that have been shown to exhibit exceptional electrical conductivities as high as 1 S/cm. We demonstrate here an effective alternative method using flame made C12A7 nanopowders (NPs) produced via liquid-feed flame spray pyrolysis (LF-FSP). Nearly fully dense, single phase, and transparent C12A7 films (< 50 μm) can be produced by processing these NPs into green films by tape-casting, thermo-compression and then sintering to 1300 $℃$/3 h/O₂. Subsequent heat treatments in 20/80 H₂/N₂ replaces cage trapped O^2- ions forming C12A7:H^? followed by UV irradiation to generate C12A7:e^? with electrical conductivities of 35 mS cm^-1. C12A7:e- appears to belong to a new class of transparent conducting oxides (TCOs) that may offer commercial potential on further optimization due to low materials and processing costs, environmental stability, and natural abundance when processed efficiently.     

Simulating alternative production policies with sequence-dependent costs

This article studies various sequencing and inventory rules in a manufacturing environment with nonlinear technological coefficients and stochastic demand. Multiple products require setup on a single machine and setup time and setup cost decrease with repeated setups. Furthermore, setup operations for different products have common components and an item can benefit from the setup operation of another item. The single-level, multi-item lot size model is used to model the production environment. The learning curve is used to represent this decrease in setup time with repeated setups. The learning transmission between items affects the scheduling of the products and the resulting model considers simultaneous decisions about lot sizing and sequencing in a nonlinear formulation. The problem is formulated and various production policies are simulated. Two sequencing rules and four inventory rules are examined. A simulation experiment of 6400 runs is used to compare the schedules produced by simple policies and those produced by more involved ones. A statistical analysis of the simulation results indicates that the simple rules perform equally well and in some cases better than the computationally harder rules.     

The effect of long term under- and over-feeding of sheep on milk and plasma fatty acid profiles and on insulin and leptin concentrations

Since sheep's milk is mainly used for cheese making and milk chemical composition and fatty acids (FA) profile affect cheese yield and quality, the objective of this study was to determine the effects of different feeding levels on milk chemical composition and FA profile, as well as on plasma FA profile, and on insulin and leptin concentrations. Twenty-four sheep were assigned to three homogeneous sub-groups. Throughout the experimental period each group was fed the same diet but in quantities which met 70% (under-feeding), 100% (control) and 130% (over-feeding) of their respective energy and crude protein requirements. The results showed that the underfed sheep had higher milk fat content compared with overfed. In blood plasma the concentrations of C18:0 and C18:1 in the underfed sheep were significantly higher compared with control and overfed sheep. The concentrations of leptin and insulin were significantly higher in overfed compared with underfed sheep. Underfeeding reduced the concentrations of short chain FA (SCFA) and medium chain FA (MCFA) and increased that of C18:0 and mono unsaturated FA (MUFA) in sheep milk fat compared with controls and overfed. The concentrations of C18:0, long chain FA (LCFA) and monounsaturated FA (MUFA) in milk were significantly higher and those of SCFA, MCFA and saturated FA (SFA) significantly lower in the underfed compared with the overfed sheep. In conclusion, long term under- and over-feeding affected the sheep milk chemical composition and FA profile which consequently has an impact on milk products yield (cheese and yogurt) and quality (human health).     

Development of colour and firmness in strawberry crops is UV light sensitive, but colour is not a good predictor of several quality parameters

BACKGROUND: Strawberry ( Fragaria × ananassa Duchesne var. Elsanta) plants were grown in polytunnels covered with three polythene films that transmitted varying levels of ultraviolet (UV) light. Fruit were harvested under near‐commercial conditions and quality and yield were measured. During ripening, changes in the colour parameters of individual fruit were monitored, and the accuracy of using surface colour to predict other quality parameters was determined by analysing the correlation between colour and quality parameters within UV treatments. RESULTS: Higher exposure to UV during growth resulted in the fruit becoming darker at harvest and developing surface colour more quickly; fruit were also firmer at harvest, but shelf life was not consistently affected by the UV regime. Surface colour measurements were poorly correlated to firmness, shelf life or total phenolics, anthocyanins and ellagic acid contents. CONCLUSION: Although surface colour of strawberry fruits was affected by the UV regime during growth, and this parameter is an important factor in consumer perception, we concluded that the surface colour at the time of harvest was, contrary to consumer expectations, a poor indicator of firmness, potential shelf life or anthocyanin content. Copyright © 2011 Society of Chemical Industry     

Non destructive characterization by FOM and ESEM-EDX of ancient glass objects from the Aegean with an approach of the manufacturing technique

The aim of the present work is the application of the non destructive techniques of fiber optics microscopy (FOM) and environmental scanning electron microscopy with energy dispersive x-ray analysis (ESEM-EDX), for the characterization of a group of decorated colored glass objects, with relation to the manufacturing technique. All the glasses are in the form of small fragments, which have come to light at archaeological excavations in the area of Dodecanese in Greece and are dated at a period between the fifth and fourth century bc. Today they belong to the National Archaeological Museum of Athens. The great antiquity of the glass fragments did not allow any sampling or even micro-sampling. Thus FOM and ESEM-EDX methods were used for their microscopic examination and elemental compositional analysis. The compositional data obtained led to significant results on the level of the adopted glass technology, suggesting an identification of the coloring agents used for the production of the glass objects colorations: Pb and Sb are indicated as responsible colorants for the opaque yellow decorations, while only Sb is present in the white ones. Green glasses exhibit high levels of Fe. The dark grey coloration is attributed to Ni content, while Fe along with Mn and Ni elements are present in black glasses. Co is found to be the responsible colorant for blue glasses. In this work, the results obtained from the microscopic examination provided substantial information on the level of the employed glass manufacturing technique used, allowing us to assume that the core-forming was the main technique used for the production of the glass artifacts.     

Sustainability analysis and benchmarking of olive mill wastewater treatment methods

A large number of publications are available in the literature regarding olive mill wastewater treatment methods. However, none of the proposed methods can be considered as a best available method in terms of its effectiveness, and its environmental and economic impact. Using a literature survey, data were collected and evaluated in order for a sustainability and benchmarking analysis to be developed. Physicochemical, biological and advanced oxidation methods were evaluated and judged in terms of their effectiveness, environmental impact and cost. Effectiveness of each method was estimated in terms of COD and phenolic compounds reduction, environmental impact in terms of CO₂ production, while for the economic impact the operational costs were taken into account. Finally, a procedure is suggested for selection of the most appropriate method based on user preferences (in terms of effectiveness, environmental impact and cost). The present analysis showed that the most effective processes in terms of organics reduction are membrane filtration, electrolysis, supercritical water oxidation and photo‐Fenton. Lower environmental impact was found with anaerobic digestion, coagulation and lime processes, while the lowest cost category involves biocomposting and membrane filtration, thanks to the exploitation of byproducts (biocompost and phenolic compounds, respectively). © 2013 Society of Chemical Industry     

A holistic approach for personalization,relevance feedback &amp; recommendation in enriched multimedia content

As the prerequisites of production houses, broadcasters, advertising agencies and online publishing companies for enriched multimedia content increase rapidly, the need of innovative methods for the effective creation of enriched multimedia content is undeniable. Stemming from this need, in this paper we focus on the design, development and evaluation of a framework consisting of personalization, relevance feedback and recommendation mechanisms, as a principal method for the creation of enriched multimedia content targeted to each user’s needs, preferences and interests. As the multimedia content proliferates along with its consumption by the users, more effective ways of presenting it to the viewers are demanded in order to facilitate them with the multimedia content search and selection and improve their Quality of Experience (QoE). The main contribution of the paper is the introduction of a holistic framework that offers personalized enriched multimedia content, by extending the recommendation process to the set of enrichments that accompany the video except from the video itself and by collecting explicit and implicit relevance feedback from the interactions of the user with both the video and its enrichments. We evaluate the proposed framework following a two-step approach. Firstly, we perform extended experiments by applying reasonably simulated user interactions, in order to calibrate its parameters that refer to multiple aspects of the enriched multimedia content, aiming at high performance in terms of QoE. Here, most importantly, we have shown that appropriately designing the enrichments and considering users’ interactions with them allows for achieving a better quality in inferring users’ profiles in many realistic cases. Secondly, we integrated our proposed recommender framework within the MECANEX streaming platform in order to perform user studies about its usability within a realistic environment of use.     

Palygorskite–TiO2 nanocatalysts for photocatalytic degradation of tebuconazole in water

Palygorskite–TiO₂ nanoparticles are frequently used as nanocatalysts. In the present study, two different nanocatalysts were developed based on the use of different palygorskite–TiO₂ ratios: 40–60 and 10–90. The nanocomposites were investigated for the photocatalytic degradation of the common fungicide tebuconazole (TEB), under aquatic conditions. The samples were extensively characterized by X-ray powder diffraction, attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy and N₂ specific surface area (SSA) by Brunauer–Emmett–Teller (BET) analytical techniques. The TiO₂ nanoparticles were successfully dispersed on the mineral's surfaces and the photocatalytic activity reached 88.4% for the palygorskite–TiO₂ ratio of 40:60, where the dispersion was better as proved by the total pore volume and BET parameters (0.49 cm³/g and 258 m²/g compared to 0.33 cm³/g and 220 m²/g of the 10:90 ratio). The photocatalytic efficiency of the proposed materials was significantly higher than Degussa P25 (33.2%), and that makes the palygorskite–TiO₂ nanocomposites very promising for advanced application in fungicides' degradation in aquatic environments.     

Deterioration of a Tunisian coastal aquifer due to agricultural activities and possible approaches for better water management

The purpose of this study is to provide a better understanding of the impact of agricultural activities on groundwater quality in a semi‐arid coastal environment (Korba, Tunisia). Impacts have been assessed through groundwater samples that were analysed for a range of chemical and biological parameters. Results indicate that groundwater overexploitation for irrigation and fertiliser use have affected the quality of the groundwater not only by direct contamination but also seawater intrusion. The implementation of appropriate regulatory and economic instruments to foster sustainable practices in the agricultural sector have been analysed within the framework of the EC (European Community) FP6 (funding program 6) INECO (Institutional and Economic Instruments for Sustainable Water Management in the Mediterranean Region) Project. Through stakeholder involvement processes, the project analysed issues relating to the regulation and control of groundwater abstractions, the promotion of wastewater reuse, efficiency improvements in irrigation water use, as well as instruments to strengthen the socioeconomic and institutional environment towards better managing and conserving available groundwater resources.