Automobile air bag inflation system using pressurized carbon dioxide

A novel air bag inflator based on the evaporation ofliquefied carbon dioxide was developed. A detailed qualitative model wasestablished on the basis of an extensive experimental study. An integratedquantitative model of this inflator was constructed. The system was studied by discharging the inflatorinto a tank and measuring pressure and temperature evolution (0-50 ms). Thedispersion of the two-phase spray duringinflation was investigated by high-speed cinematography. The optimal storage pressure of the liquid CO2was found to be 2000 psig (at 22 °C). Two distinct inflator behaviors wereidentified. First, at conditions corresponding to an initial entropy below the critical point, atwo-phase evaporating spray was ejected from the inflator into the tank. Second, at an initial entropy above thecritical point, the inflationsequence constituted the expansion of a real gas without a significant phase transformation. The minimal flow section in thenozzle was found to control the dynamicsof this new inflator. To prevent the formation of solid CO2during inflation, small amounts of organic liquids were added to the inflator. A significant increase in tanktemperature was observed, resultingin a profound improvement in performance. An explanation for the influence of organic liquids was developed based ona \u27layered evaporation model\u27. The qualitative model was based on the interactionof the flashing process with thetwo-phase outflow from the inflator. This interaction was manifested in twodifferent waves, namely a forerunnerand an evaporation wave which controlled the evacuation of the two-phase mixture from the inflator. The latterwas predominantly dispersed accordingto classical atomization mechanisms. The generated droplets evaporated partially by consuming their own internal energyand by interacting with tank gases. The characteristics of the condensate were evaluated by a detailedthermodynamic analysis. The quantitative description of the inflatorinvolved the development of a transientone-dimensional, two-fluid model. Preliminary simulations show excellent agreement with the expected results. The tank modelwas formulated on the basis of an empiricalcorrelation for the atomization process, coupled with a simple droplet evaporation model, followed by a model for themixing of real gases

Chemically fuelled self-regulating gel-to-gel transition

Artificial self‐regulating materials can be prepared by exploiting fuel‐driven pathways. Dynamic covalent bonds are formed and broken reversibly under mild reaction conditions. Herein, we utilise this concept to programme a system that can undergo a fuel‐driven self‐regulated gel‐to‐gel transition. The reaction between the gelator and the fuel resulted in a change in chemical structure of the gelator that initially causes a transition from a solution to gel state by co‐assembly. With time, the intermediate complex collapses, re‐forming the gelator structure. However, the gel does not collapse. This method allows us to prepare gels with improved mechanical strength. Unlike conventional gel‐to‐gel transitions, exploitation of dynamic covalent chemistry provides an opportunity to access materials that cannot be prepared directly under similar final conditions

Generalized Geologic Map for Land-Use Planning: Wayne County, Kentucky

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock

Generalized Geologic Map for Land-Use Planning: Pulaski County, Kentucky

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock

Programming properties of transient hydrogels by an enzymatic reaction

Supramolecular gels are usually stable in time as they are formed under thermodynamic equilibrium or at least in a deep well of a kinetically trapped state. However, artificial construction of kinetically controlled transient supramolecular gels is an interesting challenge. In these systems, usually a kinetically trapped transient aggregate is formed by active building blocks that leads to gelation; the gel then typically returns to the solution state. In this work, we show that such transient aggregation can occur by successive formation of two distinctly different kinetically controlled metastable states. Control over the first metastable state allows us to achieve significant control over the stability and properties of the second metastable state

A Type Theory for Probabilistic and Bayesian Reasoning

This paper introduces a novel type theory and logic for probabilistic reasoning. Its logic is quantitative, with fuzzy predicates. It includes normalisation and conditioning of states. This conditioning uses a key aspect that distinguishes our probabilistic type theory from quantum type theory, namely the bijective correspondence between predicates and side-effect free actions (called instrument, or assert, maps). The paper shows how suitable computation rules can be derived from this predicate-action correspondence, and uses these rules for calculating conditional probabilities in two well-known examples of Bayesian reasoning in (graphical) models. Our type theory may thus form the basis for a mechanisation of Bayesian inference

Using small-angle scattering and contrast matching to understand molecular packing in low molecular weight gels

It is difficult to determine exactly the molecular packing in the aggregates in low molecular weight gels. Attempts to understand the packing have been made using X-ray diffraction, but there are complications with drying and questions as to whether the crystal structures represent the packing in the gel phase. Here, we exploit contrast matching in small-angle neutron scattering experiments. By preparing selectively deuterated analogs of the same molecule, the scattering from that section of the molecule decreases compared with the hydrogenated molecule. We examine packing in the pre-gelled solutions at high pH and in the gels at low pH. The data from the final gels show a lack of specific order in the aggregates that form the gel matrix. The packing in these systems is not well ordered in the gel state and so implies that it is likely that current models and cartoons are not correct

Innovating Pedagogy 2015: Open University Innovation Report 4

This series of reports explores new forms of teaching, learning and assessment for an interactive world, to guide teachers and policy makers in productive innovation. This fourth report proposes ten innovations that are already in currency but have not yet had a profound influence on education. To produce it, a group of academics at the Institute of Educational Technology in The Open University collaborated with researchers from the Center for Technology in Learning at SRI International. We proposed a long list of new educational terms, theories, and practices. We then pared these down to ten that have the potential to provoke major shifts in educational practice, particularly in post-school education. Lastly, we drew on published and unpublished writings to compile the ten sketches of new pedagogies that might transform education. These are summarised below in an approximate order of immediacy and timescale to widespread implementation