A review of the supply of liquid propellants and other fluids in support of the Space Shuttle Program

In this study, over twenty significant liquid propellants and other fluids were reviewed as to their supply in support of the Space Shuttle Program (SSP), primarily at KSC. The uniqueness of most of the products, either by their application or production characteristics, present a variety of supply issues to contend with. Each, however, is critical to the success of the SSP. It becomes necessary to formulate, and maintain, a logistic approach to assure a continued availability of each product. For convenience, two categories were established. One, labeled limited-availability, represents those products wherein they are single sourced, have production restrictions and/or there has been a history of supply problems. The other, labeled universally-available, is characteristic of those having several sources and/or having little, if any, historical supply problems. This last category was not examined in depth. Through concepts of establishing stockpile inventories, multiple supply contracts, or other arrangements, the supply of liquid propellants and other fluids can be assured

Cost effective flat plate photovoltaic modules using light trapping

Work in optical trapping in 'thick films' is described to form a design guide for photovoltaic engineers. A thick optical film can trap light by diffusive reflection and total internal reflection. Light can be propagated reasonably long distances compared with layer thicknesses by this technique. This makes it possible to conduct light from inter-cell and intra-cell areas now not used in photovoltaic modules onto active cell areas

Queer(ing) Urban Planning and Municipal Governance

To queer urban planning and municipal governance requires explicit civic engagement with sexual and gender minority inclusions, representations and needs in urban plans and policies across departmental and committee silos. This collection questions the hetero-cis-normative assumptions of urban planning and examines the integration of LGBTQ+ issues in municipal governance at the interface of community activism, bureaucratic procedures, and political intervention. The editorial summarizes the contributions to this thematic issue within a tripartite thematic framework: 1) counter-hegemonic reactions to hetero-cis-normativities; 2) queering plans and policies; and 3) governance coalitions and LGBTQ+ activisms

Redistributing More Than the LGBTQ2S Acronym? Planning Beyond Recognition and Rainbows on Vancouver's Periphery

Just urban planning recognizes sociocultural differences and addresses inequality by implementing redistributive mechanisms that move beyond urban neoliberal practices of aestheticization and festivalization. Such planning practices are only beginning to address sexual and gender minority recognition in central urban areas while metronormative assumptions about their geographies absolve suburban municipalities of accountability for LGBTQ+ inclusions. In suburban municipalities, therefore, an LGBTQ+ politics of recognition rarely synchronizes with a politics of redistribution to foster sustained and transformative responses across the professional and managerial boundaries between planning and other local government functions. Consequently, a reparative civic "rainbowization" stands in for transformative urban planning, producing only partial and commodifiable inclusions in the landscape that become absolution for inaction on more evidence-based goals and measurable targets. Drawing on a database of public-facing communication records referencing LGBTQ2S themes for three adjacent peripheral municipalities in the Vancouver city-region (Burnaby, New Westminster, and Surrey), this article analyses the tension between contemporary planning’s civic actions of LGBTQ+ recognition and outcomes of redistribution. In suburban municipalities, a rainbow-washing politics of recognition sidelines transformative planning and policy resulting in little more than the distribution of the LGBTQ2S acronym across municipal documents

Internal Flows and Particle Transport Inside Picoliter Droplets of Binary Solvent Mixtures

The flows in evaporating droplets of binary mixtures are much more complicated than single solvent systems. Solutal Marangoni flows are generated due to differential evaporation of components. High-speed imaging techniques are used to visualize how internal flows transport particles to build up the end deposit. Circulatory flow along streamlines develops inside droplets at the contact line or central region, depending on the direction of the Marangoni flow. Re-circulation of particles can reduce the build up of a ring stain. Additionally, particles migrate across streamlines to collect at the droplet center independent of where the circulating regions occur. Potential mechanisms for particle migration are discussed, including chemophoresis, thermophoresis and shear-induced migration

Fluid invasion of an unsaturated leaky porous layer

We study the flow and leakage of gravity currents injected into an unsaturated (dry), vertically confined porous layer containing a localized outlet or leakage point in its lower boundary. The leakage is driven by the combination of the gravitational hydrostatic pressure head of the current above the outlet and the pressure build-up from driving fluid downstream of the leakage point. Model solutions illustrate transitions towards one of three long-term regimes of flow, depending on the value of a dimensionless parameter D, which, when positive, represents the ratio of the hydrostatic head above the outlet for which gravity-driven leakage balances the input flux, to the depth of the medium. If D⩽0, the input flux is insufficient to accumulate any fluid above the outlet and fluid migrates directly through the leakage pathway. If 0<D⩽1, some fluid propagates downstream of the outlet but retains a free surface above it. The leakage rate subsequently approaches the input flux asymptotically but much more gradually than if D⩽0. If D>1, the current fills the entire depth of the medium above the outlet. Confinement then fixes gravity-driven leakage at a constant rate but introduces a new force driving leakage in the form of the pressure build-up associated with mobilizing fluid downstream of the outlet. This causes the leakage rate to approach the injection rate faster than would occur in the absence of the confining boundary. This conclusion is in complete contrast to fluid-saturated media, where confinement can potentially reduce long-term leakage by orders of magnitude. Data from a new series of laboratory experiments confirm these predictions