Backward difference formulae for Kuramoto–Sivashinsky type equations

We analyze the discretization of the periodic initial value problem for Kuramoto–Sivashinsky type equations with Burgers nonlinearity by implicit–explicit backward difference formula (BDF) methods, establish stability and derive optimal order error estimates. We also study discretization in space by spectral methods.     

Performance optimization of polymer electrolyte membrane fuel cells using the Nelder-Mead algorithm

The direct-search simplex method for function optimization has been adapted to performance optimization of polymer electrolyte membrane fuel cells (PEMFCs). The established method is strongly application oriented and uses only experimentally determined data for optimization. It is not restricted to discrete parameters optimums and does not require the use of third-party software or computational resources. Hence, it is easy to implement in fuel cell testing stations. The optimization consists of finding, for a given fuel cell load, an optimum set of values of the 7 fuel cell operating parameters: the fuel cell temperature, the reactants' stoichiometric ratios, the reactants' inlet relative humidity, and the reactants' outlet pressures, resulting in the highest fuel cell performance. The performance is measured using a scalar function of the operating parameters and the load and can be defined according to needs.Two PEMFC performance functions: the fuel cell voltage and the system-related fuel cell efficiency were optimized using the procedure for practically sized PEMFC stacks of two designs. With respect to the nominal operating conditions defined as optimal for each stack design by its manufacturer, the gains from the optimization procedure were up to over 12% and up to over 7% for the stack voltage and efficiency, respectively. The validation of the procedure involved 5 stack specimens and four laboratories and consistent results were obtained.     

On Supporting Secure Information Distribution in Heterogeneous Systems Using Standard Technologies

This paper presents an integrated security architecture for heterogeneous distributed systems. Based on the MPEG-21 standard data structures and the MPEG-M standard services, the proposed architecture provides a unified, fine-grained solution for protecting each information unit circulated in the system. In this context, a novel scheme for translating the access control rules, initially expressed by means of the standard MPEG-21 Rights Expression Language, into Ciphertext-Policy Attribute-Based Encryption access trees is introduced, thereby enabling offline authorization based on the users’ attributes, also encapsulated and certified using MPEG-21 licenses. The proposed framework provides a detailed approach in all the steps of the information protection process, from attribute acquisition to data encryption and decryption.     

Physical characterization of thermally induced networks of lupin protein isolates prepared by isoelectric precipitation and dialysis

Summary Protein isolates of Lupinus albus were obtained from full fat and defatted lupin flour using isoelectric precipitation or dialysis. Calorimetric tests demonstrated that the main protein fractions of the isolates denature well below 100 °C. Mechanical spectra of isolate dispersions obtained at 80 °C indicated the formation of a 'pseudogel' whose cohesion increased during cooling to 10 °C. Subsequent heating to 90 °C encouraged extensive formation of disulphide bonds as it produced gels that were insoluble in sodium dodecyl sulphate and urea solutions. Dialysis produced isolates of lower gelling concentrations, which also formed networks of a stronger relative elastic character. The presence of NaCl at concentrations up to 0.5 m had a reinforcing effect on networks. Protein over-aggregation caused the opposite effect at higher salt levels. Finally, a comparison with results in the literature on soybean protein gelation suggested similar denaturation temperatures and a common pattern of structure formation for the two legume proteins.     

Microbiological quality of tomatoes and peppers produced under the good agricultural practices protocol AGRO 2-1 & 2-2 in Crete, Greece

The efficiency of the good agricultural practices (GAP) protocol AGRO 2-1 & 2-2, in advancing microbiological-quality of tomatoes and peppers, was studied in greenhouses at Ierapetra, Crete, Greece. The 240 tested vegetables-samples, produced under AGRO 2-1 & 2-2, showed satisfactory quality: Listeria monocytogenes absent per 25 g; Escherichia coli < 20 Colony Forming Units per gram (CFU/g); total coliforms 4.37–4.68 log CFU/g; aerobic plate counts 5.78–5.92 log CFU/g. Based on actual results and practices evaluation, we conclude that AGRO 2-1 & 2-2 can reduce microbial hazards for consumers and furthermore can establish practices in compliance to basic Euro-Retailer-Produce GAP (EUREPGAP) requirements.     

PEM fuel cell stack testing in the framework of an EU-harmonized fuel cell testing protocol: Results for an 11 kW stack

Fuel cell testing and standardization thematic network (FCTESTNET) was a Thematic Network funded by the European Commission under the Fifth Framework Program (FP5), which was comprised of 55 European partners. The project concluded in 2006 and the main output was the collection and compilation of agreed testing procedures for different fuel cell technologies (PEM, SOFC, MCFC), applications (stationary, portable, transport), as well as balance of plant.     

Simple method for coating Si (1 0 0) surfaces with ferritin monolayers—Iron oxide quantum dots

With the goal to develop iron oxide quantum dots we developed a simple method to spread horse spleen ferritin monolayers on a Si (1 0 0) surface. Application of atomic force microscopy and spectroscopic ellipsometry showed the existence of regions with dense ferritin monolayers. Application of transmission electron microscopy identified the core of the spread ferritin as FeO nanocrystals.     

Magnetic carbon nanotubes with particle-free surfaces and high drug loading capacity

Open-ended, multi-wall carbon nanotubes (CNTs) with magnetic nanoparticles encapsulated within their graphitic walls (magCNTs) were fabricated by a combined action of templated growth and a ferrofluid catalyst/carbon precursor, and tested as drug hosts. The hybrid nanotubes are stable under extreme pH conditions due to particle protection provided by the graphitic shell. The magCNTs are promising for high capacity drug loading given that the magnetic functionalization did not block any of the active sites available for drug attachment, either from the CNT internal void or on the internal and external surfaces. This is in contrast to typical approaches of loading CNTs with particles that proceed through surface attachment or capillary filling of the tube interior. Additionally, the CNTs exhibit enhanced hydrophilic character, as shown by water adsorption measurements, which make them suitable for biological applications. The morphological and structural characteristics of the hybrid CNTs are evaluated in conjunction to their magnetic properties and ability for drug loading (diaminophenothiazine). The fact that the magnetic functionality is provided from 'inside the walls' can allow for multimode functionalization of the graphitic surfaces and makes the magCNTs promising for targeted therapeutic applications.     

An Autonomic QoS-centric Architecture for Integrated Heterogeneous Wireless Networks

In this paper the problem of seamless mobility and proficient joint radio resource management over an all-IP internetworked wireless heterogeneous environment is addressed. Nodes’ autonomicity is envisioned as the enabler to devise a Quality of Service (QoS) aware architecture for supporting a variety of services, founded on a common utility based framework that provides enhanced flexibility in reflecting different access networks’ type of resources and diverse QoS prerequisites, under a unified QoS-aware resource allocation optimization problem. This allows a more in-depth intrinsic wireless network convergence, beyond All-IP, driven by QoS-oriented resource management. This vision is demonstrated and instantiated for integrated WLAN and cellular (both CDMA and OFDMA) networks, providing a viable path towards the evolution and realization of the future wireless networking paradigm. Initial numerical results demonstrate the effectiveness of the proposed architecture and reveal the benefits of such a service oriented paradigm against other existing access oriented autonomic designs.     

HILIC-UPLC-MS for exploratory urinary metabolic profiling in toxicological studies

Hydrophilic interaction ultra performance liquid chromatography (HILIC-UPLC) permits the analysis of highly polar metabolites, providing complementary information to reversed-phase (RP) chromatography. HILIC-UPLC-TOF-MS was investigated for the global metabolic profiling of rat urine samples generated in an experimental hepatotoxicity study of galactosamine (galN) and the concomitant investigation of the protective effect of glycine. Within-run repeatability and stability over a large sample batch (>200 samples, 60 h run-time) was assessed through the repeat analysis of a quality control sample. Following system equilibration, excellent repeatability was observed in terms of retention time (CV < 1.7%), signal intensity (CV < 14%), and mass variability (<0.005 amu), providing a good measure of reproducibility. Classification of urinary metabolic profiles according to treatment was observed, with significant changes in specific metabolites after galN exposure, including increased urocanic acid, N-acetylglucosamine, and decreased 2-oxoglutarate. A novel finding from this HILIC-UPLC-MS approach was elevated urinary tyramine in galN-treated rats, reflecting disturbed amino acid metabolism. These results show HILIC-UPLC-MS to be a promising method for global metabolic profiling, demonstrating high within-run repeatability, even over an extended run time. Retention of polar endogenous analytes and xenobiotic metabolites was improved compared with RP studies, including galN, N-acetylglucosamine, oxoglutarate, and urocanic acid, enhancing metabolome coverage and potentially improving biomarker discovery.