Microgravity research at the University of Mexico: Experiments in payload G-006

The experiments contained in the G-006 payload related to thin film vapor deposition, vacuum variations in a chamber vented to space, solidification of a Zn-Al-Cu alloy, and multiple location temperature monitoring for thermal model validation are described in detail. A discussion of the expected results is presented, together with the methods selected to conduct the postflight analysis, and finally, a overview of the future activities in this field

Роль структурных параметров нанокристаллов в механическом поведении аморфно-нанокристаллических сплавов

Результаты исследования влияния структурных параметров нанокристаллической фазы, образующейся при контролируемой кристал­лизации сплава типа Finemet, на изменение его механических характеристикyesБелгородский государственный университе

Pollen allergens do not come alone: pollen associated lipid mediators (PALMS) shift the human immue systems towards a TH2-dominated response

Pollen allergy is characterized by a TH2-biased immune response to pollen-derived allergens. However, pollen-exposed epithelia do not encounter pure allergen but rather a plethora of protein and non-protein substances. We demonstrated that pollen liberate lipids with chemical and functional similarities to leukotriens and prostaglandins - the pollen associated lipid mediators (PALMs). To date, two main groups of PALMs have been characterized: The immunostimulatory PALMs activating innate immune cells such as neutrophils and eosinophils, and the immunomodulatory E1-phytoprostanes blocking IL-12 production of dendritic cells, resulting in the preferential induction of TH2 responses. This article reviews our work in the field of PALMs and their effects on cells of the innate and adoptive immune system. From recent results a general picture starts to emerge in which PALMs (and possibly other pollen-associated substances) may - independently from protein allergens - propagate an overall TH2 favoring micromilieu in pollen exposed tissue of predisposed individuals

Effect of Drag Reducing Agents (DRA) in Water Injection Well

Applying drag reducing agent (DRA) into water injection system has improved injection capacity of wells by reducing the friction that occurs inside the well tubing. Many studies were conducted to understand the behaviour and optimise the performance of DRA when applied in multiphase flow. However, less study is being done to evaluate the effect of DRA on the formation, especially in the near wellbore zone. It is expected that DRA in injected water will cause permeability reduction, albeit the factor and exact percentage of reduction are subject to the current study. A water injection system using core flood equipment was used in this work. Polyacrylamide (PAM) and polysaccharide (Xanthan Gum) were mechanically degraded under high shear rates before injected into the core to simulate field condition. Injection rates were varied so that the relationship between permeability reduction and the rates could be established. It is found that low injection rate of 1cc/min gives more permeability reduction compared to high injection rates at 5cc/min, while Xanthan gum DRA solution gives more permeability reduction compared to polysaccharide DRA solution. Backflow was performed to restore core permeability, but the permeability restored was less than initial permeability. CT scan was run to study the permeability reduction of the core. However, no significant difference was observed. It is suggested that the injection rates need to be considered when designing the water injection wells with DRA additives

Experimentación en condiciones de gravedad reducida

Como es bien sabido, la ley de gravitación de Newton establece que entre dos cuerpos de masas M y m, cuyos centros de masas están separados entre sí una distancia r, aparece una fuerza de atracción que es proporcional al producto de las masas e inversamente proporcional al cuadrado de la distancia: F = GMmr−2, es la constante de proporcionalidad, G, es la denominada constante de gravitación universal, que vale G ≈6,6710−11 m3•s−2•kg−1. Esta fuerza es la atracción gravitatoria, y la generalización del enunciado a n cuerpos es obvia. En las proximidades de la Tierra el efecto dominante en la atracción gravitatoria es debido a la masa de la Tierra (aunque en algunos casos se deben tener en cuenta también otras masas menores próximas a nuestro planeta, la Luna, o grandes masas más alejadas, el Sol). Substituyendo en la expresión anterior el valor de la masa de la Tierra y de su radio medio se obtiene que, en su superficie, F = g0m, con g0 = GMr−2 = 9,81 m•s−2, valor bien conocido

Enhancement of drag and mixing in a dilute solution of rodlike polymers at low Reynolds numbers

We study the dynamics of a dilute solution of rigid rodlike polymers in a viscous fluid at low Reynolds number by means of numerical simulations of a simple rheological model. We show that the rotational dynamics of polymers destabilizes the laminar flow and causes the emergence of a turbulent-like chaotic flow with a wide range of active scales. This regime displays an increased flow resistance, corresponding to a reduced mean flow at fixed external forcing, as well as an increased mixing efficiency. The latter effect is quantified by measuring the decay of the variance of a scalar field transported by the flow. By comparing the results of numerical simulations of the model in two- and three-dimensions, we show that the phenomena observed are qualitatively independent on the dimensionality of the space.Comment: 18 pages, 13 figure

HT_FED2004-56432 Mechanical Degradation Effects on Turbulent Flows with Macro- Molecular Polymer Structures

ABSTRACT Macro-molecular polymer structures due to either the entanglement of polymer molecules or the ionic character of the polymer, have been shown in the literature to enhance the drag reducing abilities of polymer solutions in internal water flows. The purpose of this study is to contrast the performance of an ionic and a non-ionic polymer as drag reduction agents with and without the presence of such macro molecular polymer structures. The endurance of such polymer structures to mechanical degradation is also assessed and documented herein. It will also be shown that special attention needs to be paid to the design of optimum polymer delivery systems since they can contribute to the formation or to further enhancing the drag reducing abilities of homogeneous polymer solutions