Noncircular Orifice Holes and Advanced Fabrication Techniques for Liquid Rocket Injectors (Phases 1, 2, 3, and 4)

A comprehensive summary of the results of a cold-flow and hot-fire experimental study of the mixing and atomization characteristics of injector elements incorporating noncircular orifices is presented. Both liquid/liquid and gas/liquid element types are discussed. Unlike doublet and triplet elements (circular orifices only) were investigated for the liquid/liquid case while concentric tube elements were investigated for the gas/liquid case. It is concluded that noncircular shape can be employed to significant advantage in injector design for liquid rocket engines

Ways of Knowing Transcultural Herbal Healing

This project was born from 5 years of deeply moving transcultural learning experiences. As I walked with cultural guides from the Pine Ridge Reservation in South Dakota, energy workers of the Celtic tradition in England, traditional folk healers in Mexico, healers of the US southwest, Alaska natives, and Italian mountain people, stories unfolded which showed a universal commonality; a connection to the land and the use of herbs for health and healing. Across the globe, herbal remedies are used by people of all cultures for health and healing throughout the lifespan. Within many cultures, knowledge of herbs is a source of pride and identity, as a part of cultural tradition passed down through generations. As nurses become more aware of the use of herbal healing across cultures and the meaning of these practices to individuals and communities, new perspectives and deeper insights evolve that will allow the nurse to provide more meaningful and relevant care. The purpose of this project is to explore the transcultural use of herbs and the meaning of those practices. A conceptual framework is presented that expresses three o\u27ways of knowing transcultural herbal healing: (1) Analytic knowing: formal teaching and learning, body system healing, (2) Local knowing: storytelling and folk wisdom, community and family healing, and (3) Inner knowing: experiential transformation, whole healing

Theoretical mass sensitivity of Love wave and layer guided acoustic plate mode sensors

A model for the mass sensitivity of Love wave and layer guided shear horizontal acoustic plate mode (SH–APM) sensors is developed by considering the propagation of shear horizontally polarized acoustic waves in a three layer system. A dispersion equation is derived for this three layer system and this is shown to contain the dispersion equation for the two layer system of the substrate and the guiding layer plus a term involving the third layer, which is regarded as a perturbing mass layer. This equation is valid for an arbitrary thickness perturbing mass layer. The perturbation, Δν, of the wave speed for the two-layer system by a thin third layer of density, ρp and thickness Δh is shown to be equal to the mass per unit area multiplied by a function dependent only on the properties of the substrate and the guiding layer, and the operating frequency of the sensor. The independence of the function from the properties of the third layer means that the mass sensitivity of the bare, two-layer, sensor operated about any thickness of the guiding layer can be deduced from the slope of the numerically or experimentally determined dispersion curve. Formulas are also derived for a Love wave on an infinite thickness substrate describing the change in mass sensitivity due to a change in frequency. The consequences of the various formulas for mass sensing applications are illustrated using numerical calculations with parameters describing a (rigid) poly(methylmethacrylate) wave-guiding layer on a finite thickness quartz substrate. These calculations demonstrate that a layer-guided SH–APM can have a mass sensitivity comparable to, or higher, than that of Love waves propagating on the same substrate. The increase in mass sensitivity of the layer guided SH–APMs over previously studied SH–APM sensors is of significance, particularly for liquid sensing applications. The relevance of the dispersion curve to experiments using higher frequencies or frequency hopping and to experiments using thick guiding layers is discussed

Building a grounded theory of engagement in mindfulness-based group therapy for distressing voices

Mindfulness based group therapy shows promise as a treatment for distressing voice-hearing. However, fostering engagement in groups can be challenging, and no theory of engagement in group therapy for distressing voices exists to guide practice or research. This study employed Grounded Theory Method to build a theory of engagement in mindfulness based groups for distressing voices. Ten service-users and three therapists were interviewed about their experiences of such groups. The model that emerged involves a recursive process of investing in change and continually evaluating its usefulness and safety. Barriers to engagement were often overcome, but sometimes compromised perceived safety, leading to dropout. For others, group participation led to rewards, some of which were integrated beyond group termination. Group engagement can be encouraged by establishing universality around voice-hearing early, reducing uncertainty, sharing difficulties with mindfulness practices and mapping group progress to create a cohering sense of collaboration on therapy tasks

Oxygen surface exchange and diffusion in fast ionic conductors

The rate of oxygen surface exchange on selected bulk oxides exhibiting enhanced oxygen ion conductivity has been derived by measuring 18O penetration profiles using a high sensitivity dynamic SIMS technique. These values for the oxygen surface exchange coefficient (K) were used to derive the steady-state oxygen fluxes through the oxide surface for conditions when the bulk oxide was in equilibrium with 1 atm. of oxygen at 500 and 700°C. The oxygen fluxes were transformed into current fluxes and compared with available exchange current densities (iO) measured using electrochemical techniques. The two sets of current densities exhibited large differences for zirconia based electrolytes which confirmed the important role of platinum as an electro-catalyst. However for bismuth based electrolytes good agreement was noted between the two sets of iO values. It was concluded therefore that the dissociative adsorption of oxygen occurred predominately on the surface of the Bi2O3 based electrolyte and that the presence of a metal electrode (Pt or Au) had little effect upon the overall exchange current kinetics

Noncircular orifice holes and advanced fabrication techniques for liquid rocket injectors. Phase 3: Analytical and cold-flow experimental evaluation of rectangular concentric tube injector elements for gas/liquid application. Phase 4: Analytical and experimental evaluation of noncircular injector elements for gas/liquid and liquid/liquid application

Results are presented of a cold-flow and hot-fire experimental study of the mixing and atomization characteristics of injector elements incorporating noncircular orifices. Both liquid/liquid and gas/liquid element types are discussed. Unlike doublet and triplet elements (circular orifices only) were investigated for the liquid/liquid case while concentric tube elements were investigated for the gas/liquid case. It is concluded that noncircular shape can be employed to significant advantage in injector design for liquid rocket engines

Surface roughness and interfacial slip boundary condition for quartz crystal microbalances

The response of a quartz crystal microbalance (QCM) is considered using a wave equation for the substrate and the Navier-Stokes equations for a finite liquid layer under a slip boundary condition. It is shown that when the slip length to shear wave penetration depth is small, the first order effect of slip is only present in the frequency response. Importantly, in this approximation the frequency response satisfies an additivity relation with a net response equal to a Kanazawa liquid term plus an additional Sauerbrey "rigid" liquid mass. For the slip length to result in an enhanced frequency decrease compared to a no-slip boundary condition, it is shown that the slip length must be negative so that the slip plane is located on the liquid side of the interface. It is argued that the physical application of such a negative slip length could be to the liquid phase response of a QCM with a completely wetted rough surface. Effectively, the model recovers the starting assumption of additivity used in the trapped mass model for the liquid phase response of a QCM having a rough surface. When applying the slip boundary condition to the rough surface problem, slip is not at a molecular level, but is a formal hydrodynamic boundary condition which relates the response of the QCM to that expected from a QCM with a smooth surface. Finally, possible interpretations of the results in terms of acoustic reflectivity are developed and the potential limitations of the additivity result should vapour trapping occur are discussed

Topography driven spreading

Roughening a hydrophobic surface enhances its nonwetting properties into superhydrophobicity. For liquids other than water, roughness can induce a complete rollup of a droplet. However, topographic effects can also enhance partial wetting by a given liquid into complete wetting to create superwetting. In this work, a model system of spreading droplets of a nonvolatile liquid on surfaces having lithographically produced pillars is used to show that superwetting also modifies the dynamics of spreading. The edge speed-dynamic contact angle relation is shown to obey a simple power law, and such power laws are shown to apply to naturally occurring surfaces

Electrowetting of liquid marbles

Electrowetting of water drops on structured superhydrophobic surfaces are known to cause an irreversible change from a slippy (Cassie-Baxter) to a sticky (Wenzel) regime. An alternative approach to using a water drop on a superhydrophobic surface to obtain a non-wetting system is to use a liquid marble on a smooth solid substrate. A liquid marble is a droplet coated in hydrophobic grains, which therefore carries its own solid surface structure as a conformal coating. Such droplets can be considered as perfect non-wetting systems having contact angles to smooth solid substrates of close to 180 degrees. In this work we report the electrowetting of liquid marbles made of water coated with hydrophobic lycopodium grains and show that the electrowetting is completely reversible. Marbles are shown to return to their initial contact angle for both ac and dc electrowetting and without requiring a threshold voltage to be exceeded. Furthermore, we provide a proof-of-principle demonstration that controlled motion of marbles on a finger electrode structure is possible

Plastron induced drag reduction and increased slip on a superhydrophobic sphere

On low contact angle hysteresis superhydrophobic surfaces, droplets of water roll easily. It is intuitively appealing, but less obvious, that when such material is immersed in water, the liquid will flow more easily across its surface. In recent experiments it has been demonstrated that superhydrophobic surfaces with the same high contact angle and low contact angle hysteresis may not, in fact, have the same drag reducing properties. A key performance parameter is whether the surface is able to retain a layer of air (i.e. a plastron) when fully immersed. In this report, we consider an analytical model of Stokes flow (i.e. low Reynolds number, Re, creeping flow) across a surface retaining a continuous layer of air. The system is based on a compound droplet model consisting of a solid sphere encased in a sheathing layer of air and is the extreme limit of a solid sphere with a superhydrophobic surface. We demonstrate that an optimum thickness of air exists at which the drag on this compound object is minimized and that the level of drag reduction can approach 20 to 30%. Physically, drag reduction is caused by the ability of the external flow to transfer momentum across the water-air interface generating an internal circulation of air within the plastron