A New Total Flooding Test Procedure for Evaluating Fire-Suppressant Agents

A simple laboratory apparatus is described for observing the performance of fire extinguishing agents in total flooding applications. Known compositions of agents mixed with dry air are prepared in a 2 L glass combustion flask, and a flame fed by propane, butane, or other gaseous fuel from a pressure cylinder is inserted into the flask through a standard taper joint. Burning times to extinguishment are measured, both in the absence and presence of added physical or chemical agents. From the known rate of propane burning and initial compositions, the percentages of gas volume in the combustion flask at extinguishment are calculated for each burning time. Agents that are not sufficiently volatile to be investigated with the ordinary cup burner method are readily studied with the new technique.An adiabatic flame temperature model previously used to correlate cup burner test results has been applied to obtain limiting agent percentages required for total flooding extinguishment and to accurately predict the effect on burning time of different concentrations of physical and chemical agents and other gases in the flask.     

Sputter deposition of silicon oxynitride gradient and multilayer coatings

The optical properties of silicon oxynitride films deposited by reactive dc magnetron sputtered films have been investigated. In particular the absorption characteristics of silicon nitride thin films in the visible spectrum and their optical bandgap were analyzed with regard to their composition and deposition properties. It can be shown that there is a significant difference between the absorption in the visible spectrum and the optical bandgap for these layers. The influence of unipolar and bipolar pulse modes on the optical layer properties is presented. The extinction coefficient for silicon nitride single layers could be reduced to a value of 2 x 10(-4) at 500 nm without external heating. There is also the dependence of the absorption of silicon oxynitride layers on the discharge voltage. We present the resulting spectra of rugate and edge filters that consist of these layers and offer lower absorption than single layers.     

Onset of smoldering in cotton: Effects of density

The ignition temperature for smoldering in cotton has been determined for several densities. Experiments and consistent theoretical calculations show that an increase in density leads to decrease in ignition temperature. Experimentally it is found that repeated heating of a cotton sample results in a higher ignition temperature than for samples heated once, as a result of partial decomposition during heating. For the lowest density investigated, smoldering occurs but is not self-sustained. The smoldering front moves through the cotton with a velocity independent of the density. The mass loss rate due to smoldering increases with density. It can be concluded that density affects both the ignition temperatures and the mass loss rates in a systematic way.     

5-(3′,4′-Dihydroxyphenyl)-γ-Valerolactone Is a Substrate for Human Paraoxonase: A Novel Pathway in Flavan-3-ol Metabolism

Scope

Dietary flavan-3-ols are known to mediate cardiovascular benefits. Currently, it is assumed that the levels of flavan-3-ol catabolites detected in humans, 5-(3ʹ,4ʹ-dihydroxyphenyl)-γ-valerolactone (γVL) and 5-(3ʹ,4ʹ-dihydroxyphenyl)-γ-valeric acid (γVA), and their corresponding phase II metabolites, are determined exclusively by the action of the gut microbiome. However, a family of human proteins, paraoxonase (PON), can theoretically hydrolyze γVL metabolites into the corresponding γVAs. This study aims to determine if PON is involved in γVL and γVA metabolism in humans.

Methods and results

A rapid conversion of γVL into γVA is detected in serum ex vivo (half-life = 9.8 ± 0.3 min) that is catalyzed by PON1 and PON3 isoforms. Phase II metabolites of γVL are also reacted with PON in serum. Following an intake of flavan-3-ol in healthy males (n = 13), the profile of γVA metabolites detected is consistent with that predicted from the reactivity of γVL metabolites with PON in serum. Furthermore, common PON polymorphisms are evaluated to assess the use of γVL metabolites as biomarkers of flavan-3-ol intake.

Conclusion

PONs are involved in flavan-3-ol metabolic pathway in humans. PON polymorphisms have a minor contribution to inter-individual differences in the levels of γVL metabolites, without affecting their use as a nutritional biomarker.     

Changes in biogenic amine contents, non-protein nitrogen and crude protein during curing and thermal processing of M. longissimus, pars lumborum of pork

Changes in histamine, putrescine, cadaverine and tyramine, weight, dry matter, crude protein and non-protein nitrogen were studied during immersion-curing (brine with NaNO₂ and NaCl content of 0.6 g/l and 99.4 g/l, respectively and brine with NaNO₂ and NaCl content of 0.6 g/l and 199.4 g/l, respectively) and boiling and grilling (70 °C core temperature) of both “fresh” and “stored” (storage 5 days at 4 °C) pork loin chops. Amine concentrations were significantly higher in “stored” pork; this difference was preserved during most of the processing techniques. Correlations of amines with nonprotein nitrogen were weak and not significant, but strong and significant for putrescine: cadaverine (r=0.89) as well as putrescine: tyramine (r=0.95). Amine reductions for “fresh” pork were not pronounced. In “stored” pork both cooking in water (water/meat = 1:1, weight base) and curing in the less concentrated brine resulted in mean reductions of 65, 77, and 68% for putrescine, cadaverine and tyramine, respectively. Boiling of cured samples yielded reductions of 50–77, 74–80, 67–71, and 77–91% for histamine, tyramine, putrescine and cadaverine, respectively.

A new methodological framework for design for additive manufacturing

Additive manufacturing (AM) offers numerous benefits for innovative design solutions. However, engineers are currently not supported in identifying and incorporating these potentials systematically in their design solutions. In this paper, previous Design for Additive Manufacturing (DfAM) approaches are first reviewed comprehensively and classified into distinct categories according to their main purpose and application. They are then analysed further by being related to conventional design methodologies like VDI 2221. Since previous DfAM approaches only provide selective assistance at single steps in the product development process, a new framework for DfAM is proposed. Existing methods and tools, both from DfAM and from general design methodologies, are integrated into the modular framework structure. A concept for using the framework is presented to provide design engineers with continuous support in all product development phases, thereby fostering the complete exploitation of AM potentials and the development of AM-conformal designs.     

Born Global or Born to Run? The Long-Term Growth of Born Global Firms

Born global firms have stimulated substantial academic attention as regards their start up but research has neglected their subsequent, ongoing internationalisation. This contribution extends analysis from the inception and childhood to the growth and maturity of such firms. We investigate whether born global are also “born to run” companies; we also try to reconcile the analysis of international new ventures in international entrepreneurship studies with the approaches based on fast growing firms and gazelles. We initially present the latest advances in the modelling of accelerated internationalisation over time; we then discuss and develop a conceptual framework and a model that captures the variables that affect born global firms’ evolution in an holistic perspective; finally, we match case study analysis with the framework and discuss our findings. The results show two groups of firms that differ significantly in long-term internationalisation paths and growth cycles. We highlight turning points in these paths and discuss the drivers which lead to sustained high growth. The characteristics of the entrepreneurial/management teams, strategic partnerships and the entry in complex markets are the main differentiators in growth patterns, irrespectively of the industry. The “openness” of the founders and the early preparation for growth determine both the extent of organizational learning and the speed at which it is developed and used. We see said learning and its speed in development and use as the underlying, necessary mechanism of sustained high growth.     

„Check Verbraucherpolitik und Verbraucherbeteiligung“ – Empfehlungen für eine evidenzbasierte Verbraucherpolitik

The paper discusses the opportunities for an empirically grounded decision support system as an instrument for independent and scientifically based consumer policy consulting. To date, consumer policy is dominated by the information paradigm and the leitbild of the rational, sovereign and information-seeking consumer. Yet, both everyday practice and research in behavioural economics show that this view lacks empirical ground. In fact, there are different consumer types and different forms of rationalities at work. Effective consumer policy making should be based on the empirically revealed behaviour of consumers, not on an ideal model. Moreover, it is often not clear how much consumer policy measures actually contribute to the consumer interest, and whether there would be more effective and efficient policy instruments to strengthen the consumer position. The authors suggest introducing an empirically based “Check Consumer Policy and Consumer Participation” as a systematic decision and evaluation tool for policy makers. This check should be independent from the government and should be grounded on an empirical view of the consumer. Consumer policy tools should be tested with real consumers. The authors suggest an independent national “Expert Council for Consumer Policy” as an ideal candidate to supervise this work.     

A radiant heat flux apparatus for measuring the thermal response of polymeric materials to high temperatures

An efficient and economical experimental apparatus has been designed and built which delivers a known radiant heat flux and simultaneously measures the in-depth temperature profiles in polymeric materials. Test samples are maintained in a controlled environment and are heated radiantly by a silicon carbide heating element capable of producing heat fluxes up to 7.0 cal/cm²-sec. The experimental data produced by this device are extremely accurate and therefore are suitable for use in verification of numerical models. The utility of the apparatus was demonstrated by measuring temperature profiles to approximately 1000°C in a glass-filled phenol-formaldehyde resin.     

High energetic materials: Reaction of Azides with Dioxygenyl Salts

The reactivity of sodium azide, activated sodium azide and hydrazinium azide towards various dioxygenyl salts was studied. Under no circumstances the formation of dioxygenyl azide, O₂N₃, could be observed. This is in agreement with high level quantumchemical ab initio computations at correlated level (MP2, PMP2, CISD), predicting the decomposition of hypothetical O₂⁺(g)/N₃⁻(g) to be thermodynamically highly favorable (MP2: −326; PMP2: −328; CISD; −369 [kcal/mol]). The combustion of O₂BF₄ with either N₂H₅N₃ (spontaneous reaction on contact in a coaxial solid-propellant system) or NaN₃ (safe to handle, highly exothermic reaction after ignition) is discussed in terms of high-energy-density materials (HEDM).