Steady-state performance and chemical efficiency of Microbial Electrolysis Cells

The objective of this paper was to study MEC performance at steady-state conditions in continuous mode and to analyse MEC performance in terms of chemical efficiency. At steady-state operation, a current density of 10.2 A m⁻² (applied voltage 1.0 V) for a set-up with an AEM was produced, compared to 7.2 A m⁻² for a set-up with a CEM. For all applied voltages, total internal resistance for the AEM configuration was lower than or the CEM configuration. Therefore, energy input for the AEM configuration is lower than for the CEM configuration. In case a CEM is used, the conductivity in the cathode reaches high values: >130 mS cm⁻¹. This conductivity is mainly caused by the presence of Na⁺ (7.8 g L⁻¹), K⁺ (12.2 g L⁻¹) and OH⁻ (8.3 g L⁻¹). Furthermore, MECs perform better at high buffer and electrolyte concentrations. However, as current density does not increase proportionally with increase in chemicals, the effectiveness of chemical addition decreases when more chemicals are added. Therefore, addition of chemicals and buffer does not necessarily enhance performance but increases operational costs.     

Ethernet Topology Discovery： A Survey

Ethemet networks have undergone impressive growth since the past few decades. This growth can be appreciated in terms of the equipment, such as switches and links, that have been added, as well as in the number of users that it supports. In parallel to this expansion, over the past decade the networking research community has shown a growing interest in discovering and analyzing the Ethernet topology. Research in this area has concentrated on the theoretical analysis of Ethemet topology as well as developing tools and methods for mapping the network layout. These efforts have brought us to a crucial juncture for Ethernet topology measurement infrastructures： while, previously, these were both small （in terms of number of measurement points）, people are starting to see the deployment of large-scale distributed systems composed of hundreds or thousands of monitors. As all look forward to this next generation of systems, all take stock of what has been achieved so far. In this survey, the authors discuss past and current mechanisms for discovering the Ethernet topology from theoretical and practical prospective. In addition to discovery techniques, the authors provide insights into some of the well-known open issues related to Ethernet topology discovery.     

Seeing the bond: Acoustic imaging of seals in medical cartridges

It is important to be able to check the quality of seal, and this article looks at the use of acoustic micro imaging to inspect the bonding of a film t     

Truss layout optimization within a continuum

The present work extends truss layout optimization by considering the case when it is embedded in a continuum. Structural models often combine discrete and continuum members and current requirements for efficiency and extreme structures push research in the field of optimization. Examples of varied complexity and dimensional space are analyzed and compared, highlighting the advantages of the proposed method. The goal of this work is to provide a simple formulation for the discrete component of the structure, more specifically the truss, to be optimized in presence of a continuum.     

After a Terrorist Attack: Challenges for Political and Administrative Leadership in Norway

This article addresses the challenges that the terrorist attacks on 22 July 2011 in Norway created for central government and, more particularly, for the political and police leadership. The emphasis is on ‘meaning making’, focusing on how the leaders played out their reactions in the media and towards the public. When explaining the different aspects of crisis management, we draw on three organizational perspectives: emphasizing the importance of myths and symbols, formal organization and cultural–institutional traditions. The analysis is based on qualitative content analysis of central policy documents, parliamentary debates and documents, speeches made by central actors and mass media coverage in the year following the attacks. A main finding is that the response to the terrorist attacks is characterized by complex interactions between mutually influential factors, by dynamics between symbolic factors, on one hand, and structural and cultural influences, on the other.     

Wear and oxidation resistance of combustion CVD grown alumina films

Alumina thin films were synthesized on Si (100) and Ni–20Cr substrates using combustion chemical vapor deposition. Aluminum acetylacetonate (0.005 M) dissolved in ethanol was used as the precursor solution. The films deposited at 900 and 1000 °C are found to be θ-alumina and those deposited at 1100 °C to be α-alumina. The scanning electron micrographs showed the films to be made up of crystallites of two different sizes and shapes. The coefficient of friction, of alumina coated Si samples, measured using a tribometer showed high value (~ 0.7) at initial passes and subsequently saturated to low value (~ 0.5) at higher sliding distances. It was observed that the tribological properties, of the films, are not affected significantly by the crystal structure and crystallite size. Oxidation resistance of alumina-coated Ni–20Cr specimens were studied using a thermo-gravimetric analyzer by exposing them to isothermal heating at 1000 °C in 20% O₂–Ar gas mixture. The results indicated that the coated specimens are 18 times more oxidation resistant, at initial stages, compared to uncoated specimens. The resistance slowly dropped to six times, where it reached a saturation value.     

The role of Si interstitials in the migration and growth of Ge nanocrystallites under thermal annealing in an oxidizing ambient

We report a unique growth and migration behavior of Ge nanocrystallites mediated by the presence of Si interstitials under thermal annealing at 900°C within an H₂O ambient. The Ge nanocrystallites were previously generated by the selective oxidation of SiGe nanopillars and appeared to be very sensitive to the presence of Si interstitials that come either from adjacent Si₃N₄ layers or from within the oxidized nanopillars. A cooperative mechanism is proposed, wherein the Si interstitials aid in both the migration and coarsening of these Ge nanocrystallites through Ostwald ripening, while the Ge nanocrystallites, in turn, appear to enhance the generation of Si interstitials through catalytic decomposition of the Si-bearing layers.