Towards ultrastrong glasses

The development of new glassy materials is key for addressing major global challenges in energy, medicine, and advanced communications systems. For example, thin, flexible, and large-area glass substrates will play an enabling role in the development of flexible displays, roll-to-roll processing of solar cells, next-generation touch-screen devices, and encapsulation of organic semiconductors. The main drawback of glass and its limitation for these applications is its brittle fracture behavior, especially in the presence of surface flaws, which can significantly reduce the practical strength of a glass product. Hence, the design of new ultrastrong glassy materials and strengthening techniques is of crucial importance. The main issues regarding glass strength are discussed, with an emphasis on the underlying microscopic mechanisms that are responsible for mechanical properties. The relationship among elastic properties and fracture behavior is also addressed, focusing on both oxide and metallic glasses. From a theoretical perspective, atomistic modeling of mechanical properties of glassy materials is considered. The topological origin of these properties is also discussed, including its relation to structural and chemical heterogeneities. Finally, comments are given on several toughening strategies for increasing the damage resistance of glass products.     

Lupine,a source of new as well as hidden food allergens

The present review summarizes current knowledge about lupine allergy, potential sensitization routes, cross‐reactions between lupine and other legumes, and the respective IgE‐binding proteins. Since the 1990s, lupine flour is used as a substitute for or additive to other flours, mostly wheat flour, in several countries of the EU. In 1994, the first case of an immediate‐type allergy after ingestion of lupine flour‐containing pasta was reported. Since then, the number of published incidents following ingestion or inhalation of lupine flour is rising. So far, the Lupinus angustifolius β‐conglutin has been designated as the allergen Lup an 1 by the International Union of Immunological Societies Allergen Nomenclature Subcommittee. Initially, publications focussed on the fact that peanut‐allergic patients were at risk to develop anaphylaxis to lupine due to cross‐reactivity between peanut and lupine. At present, however, the ratio between cases of pre‐existing legume allergy (mostly peanut allergy) to de novo sensitization to lupine seed is nearly 1:1. Although in December 2006, lupine and products thereof were included in the EU foodstuff allergen list according to the Commission Directive 2006/142/EC amending Annex IIIA of Directive 2000/13/EC in order to prevent severe reactions caused by “hidden food allergens”, the majority of patients and medical personnel are still not aware of raw lupine seed as potentially dangerous food allergen.     

Ignorance is no Defence, but is Inaccessibility? On the Accessibility of National Laws to Foreign Online Publishers

The article examines, first, to what extent the legal exposure of online actors to multiple foreign laws creates a legal obligation on states to make their laws easily accessible to them and whether a state by failing to do so breaches any human rights. Second, it is examined what 'easy accessibility' actually entails. The discussion builds upon the premise that the Internet has created an environment where transnational trade or publications are no longer the prerogative of resource-rich multinational companies with large inhouse legal departments to advise them on their respective legal position in different jurisdictions. Yet, there is growing worldwide consensus that online content providers have to comply with the laws of the places where their sites can be accessed. This raises the issue of whether the legal expectation of states on foreign online actors goes, or should go, hand-in-hand with an obligation to cater for the special regulatory needs of foreign actors.     

Environmental influences on the partitioning and diffusion of hydrophobic organic contaminants in microbial biofilms

A biofilm reactor was used to investigate kinetic and thermodynamic aspects of the sorption of polycyclic aromatic hydrocarbons (PAH) as model compounds for hydrophobic organic contaminants (HOC) to intact microbial biofilms. Effective diffusion coefficients are in the range of 10(-10) cm2 x s(-1) resulting in equilibration times of more than 3 days for a biofilm of 100 microm thickness. Diffusion in the biofilm was strongly temperature-dependent and increased by a factor of 3 (phenanthrene) to 6 (fluoranthene, pyrene) between 5 and 35 degrees C. Drying and rewetting of the biofilm as well as the inclusion of Ca2+ ions and of humic acids all strengthened the biofilm rigidity and slowed down the diffusion of PAH. The later two factors also influenced the thermodynamics of the process as they supported the partitioning of PAH into the biofilm. Humic acid inclusion from solution into the biofilm illustrates that a microbial biofilm can act as a primer allowing for the buildup of a particulate organic phase from dissolved organic matter. PAH metabolites (3-hydroxy-phenanthrene and 1-hydroxy-2-naphthoic acid) showed lower partition coefficients as compared to their parent compounds and 3-hydroxy-phenanthrene also showed a higher diffusion constant, indicating that these transformation products would be easily released into the water phase upon formation during PAH biodegradation in a biofilm. These results allow the quantification of the influence of environmental conditions on a biofilm's function as a sink or as a diffusion barrier for PAH from aqueous solution, and they indicate the importance of kinetic aspects of this partitioning process.     

Stakeholder engagement in water governance as social learning: lessons from practice

ABSTRACT

The OECD Principles on Water Governance set out various requirements for stakeholder engagement. Coupled with conceptualizations of social learning, this article asks how we define and enact stakeholder engagement and explores the actual practice of engagement of stakeholders in three fields of water governance. The results suggest that a key consideration is the purpose of the stakeholder engagement, requiring consideration of its ethics, process, roles and expected outcomes. While facilitators cannot be held accountable if stakeholder engagement ‘fails’ in terms of social learning, they are responsible for ensuring that the enabling conditions for social learning are met.     

CuZr-based bulk metallic glass and glass matrix composites fabricated by selective laser melting

Monolithic bulk metallic glass and glass matrix composites with a relative density above 98 ％ were produced by processing Cu46Zr46Al8 (at.％) via selective laser melting (SLM).Their microstructures and mechanical properties were systematically examined.B2 CuZr nanocrystals (30-100 nm in diameter) are uniformly dispersed in the glassy matrix when SLM is conducted at an intermediate energy input.These B2 CuZr nanocrystals nucleate the oxygen-stabilized big cube phase during a remelting step.The presence of these nanocrystals increases the structural heterogeneity as indirectly revealed by mircrohardness and nanoindentation measurements.The corresponding maps in combination with calorimetric data indicate that the glassy phase is altered by the processing conditions.Despite the formation of crystals and a high overall free volume content,all additively manufactured samples fail at lower stress than the as-cast glass and without any plastic strain.The inherent brittleness is attributed to the presence of relatively large pores and the increased oxygen content after selective laser melting.     

Effect of Forced Aeration and Mechanical Turning on Leachate Quantity and Quality from Glass Cullet Stockpiles

Leachate from mixed glass cullet (crushed recycled glass containers) that is stockpiled before use as construction aggregate or sand substitute is a potential source of water pollution. Rainwater leaching through the stockpiles dissolves and suspends organic compounds and nutrients from the glass. The objectives of this study were to investigate the effect of forced aeration on leachate quantity and quality in the glass cullet stockpiles compared to mechanical turning/mixing. Three experimental stockpiles were set up in the field, two with forced aeration treatment (one with fine and the other with coarse cullet) and one (coarse cullet) with mechanical turning. The organic concentrations in the leachate in most cases were comparable to those of raw domestic wastewater. Organic constituents (e.g., BOD5) were reduced by>70% from the initial levels ( ～ 450?mg?L?1) during a 1.5-month period with forced aeration, compared to an 85% decrease in the turned stockpile. Particle size affected temperature and oxygen levels under aeration conditions, resulting in more biodegradation of organic contaminants in the stockpile of coarse cullet than the fine cullet.