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Dale A. Gillette - One of the best experts on this subject based on the ideXlab platform.
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Wind Characteristics of Mesquite Streets in the Northern Chihuahuan Desert
2006Co-Authors: Dale A. Gillette, Jeffrey E. HerrickAbstract:Past research has shown that the most important areas for active sand movement in the northern part of the Chihuahuan Desert are Mesquite-dominated desert ecosystems possessing sandy soil texture. The most active sand movement in the Mesquite-dominated ecosystems has been shown to take place on elongated bare soil patches referred to as "streets". Aerodynamic properties of Mesquite streets eroded by wind should be included in explaining how Mesquite streets are more emissive sand sources than surrounding desert land. To understand the effects of wind properties, we measured them at two flat Mesquite sites having highly similar soil textures but very different configurations of Mesquite. The differences in wind properties at the two sites were caused by differences of size, orientation, and porosity of the Mesquite, along with the presence of Mesquite coppice dunes (sand dunes stabilized by Mesquites growing in the dune and on its surface) found only at one of the two sites. Wind direction, u∗ (friction velocity), z0 (aerodynamic roughness height) and D (zero plane displace- ment height) were estimated for 15-m tower and 3-m mast data. These aerodynamic data allowed us to distinguish five categories with differing potentials for sediment trans- port. Sediment transport for the five categories varied from unrestricted, free transport to virtually no transport caused by vegetation protection from wind forces. In addition, "steering" of winds below the level of the tops of Mesquite bushes and coppice dunes allowed longer parallel wind durations and increased wind erosion for streets that aligned roughly SW-NE.
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Wind Characteristics of Mesquite Streets in the Northern Chihuahuan Desert, New Mexico, USA
Environmental Fluid Mechanics, 2006Co-Authors: Dale A. Gillette, Jeffrey E. Herrick, Gary HerbertAbstract:Past research has shown that the most important areas for active sand movement in the northern part of the Chihuahuan Desert are Mesquite-dominated desert ecosystems possessing sandy soil texture. The most active sand movement in the Mesquite-dominated ecosystems has been shown to take place on elongated bare soil patches referred to as “streets”. Aerodynamic properties of Mesquite streets eroded by wind should be included in explaining how Mesquite streets are more emissive sand sources than surrounding desert land. To understand the effects of wind properties, we measured them at two flat Mesquite sites having highly similar soil textures but very different configurations of Mesquite. The differences in wind properties at the two sites were caused by differences of size, orientation, and porosity of the Mesquite, along with the presence of Mesquite coppice dunes (sand dunes stabilized by Mesquites growing in the dune and on its surface) found only at one of the two sites. Wind direction, u * (friction velocity), z 0 (aerodynamic roughness height) and D (zero plane displacement height) were estimated for 15-m tower and 3-m mast data. These aerodynamic data allowed us to distinguish five categories with differing potentials for sediment transport. Sediment transport for the five categories varied from unrestricted, free transport to virtually no transport caused by vegetation protection from wind forces. In addition, “steering” of winds below the level of the tops of Mesquite bushes and coppice dunes allowed longer parallel wind durations and increased wind erosion for streets that aligned roughly SW–NE.
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sand flux in the northern chihuahuan desert new mexico usa and the influence of Mesquite dominated landscapes
Journal of Geophysical Research, 2004Co-Authors: Dale A. Gillette, Ann PitchfordAbstract:[1] Measurements of sand flux over areas with different vegetation in the Chihuahuan desert show that mean, height-integrated, horizontal flux values for Mesquite-dominated sites were higher than those for other kinds of vegetation. Sand transport over Mesquite areas displayed seasonal variability for most years. This seasonal variability roughly followed the variability of strong winds. Sand transport rates for collectors within a short distance downwind of Mesquite bushes were small compared to those for collectors at the end of streets (elongated patches of bare soil) aligned with wind direction. The increased rate of sand transport (wind erosion) associated with Mesquite is important because Mesquite-dominated areas are increasing in the northern Chihuahuan desert and are therefore responsible for increasing land degradation (desertification).
Miguel A. Valdez - One of the best experts on this subject based on the ideXlab platform.
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Classification and physicochemical characterization of Mesquite gum (Prosopis spp.)
Food Hydrocolloids, 2012Co-Authors: Yolanda L. López-franco, Raúl E. Córdova-moreno, Francisco M. Goycoolea, Miguel A. Valdez, Josué Elías Juárez-onofre, Jaime Lizardi-mendozaAbstract:Abstract Under environmental stress conditions, Mesquite trees can excrete a proteinaceous arabinogalactan gum that is similar to gum arabic. Given the application potential of this type of gums a classification procedure for the Mesquite gum is proposed. The main physicochemical properties of the best-quality Mesquite gum were determined and compared with those of gum arabic. Additionally, the composition and molecular changes induced by purification processes were recorded. One batch (157 kg) of Mesquite gum was categorized by subjective assessment into three classes (MGA, MGB and MGC) from high- to low-quality. Approximately 17.5% was classified as top-quality gum. It was found that this class of Mesquite gum has lower humidity, inorganic and tannins content than the other classes, or even than the gum arabic sample used as a reference. All of the Mesquite gum classes have higher protein content and lower intrinsic viscosity than gum arabic. The purification processes were shown to reduce the content of lower molecular weight compounds that modify the interface properties of the gum. The results indicate that the proposed classification method can be used to select Mesquite gum with physicochemical properties comparable to those of commercial gum arabic.
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zeta potential and drop growth of oil in water emulsions stabilized with Mesquite gum
Carbohydrate Polymers, 2006Co-Authors: J I Acedocarrillo, Francisco M. Goycoolea, A Rosasdurazo, R Herreraurbina, Marguerite Rinaudo, Miguel A. ValdezAbstract:Abstract The influence of the nature of the oil phase on the zeta potential and the time course evolution of mean droplet-size of emulsions stabilized with Mesquite gum have been investigated. Mesquite gum-stabilized emulsions of d -limonene, n -decane, n -dodecane, n -tetradecane n -hexadecane, and orange oil were prepared in the range of 9–22% w/w Mesquite gum concentrations to investigate the emulsion stability by analyzing creaming, zeta potential, and drop size distribution. An electrosteric mechanism of stabilization is proposed to explain the long term stability observed for orange oil–water emulsions in the range of 9–22% w/w Mesquite gum concentrations, similar to the one suggested to operate for gum arabic interfaces. Experiments of creaming for the different emulsions, showed that orange oil–water emulsions observed strong stability in time. By contrast, Mesquite gum-stabilized emulsions of d -limonene, n -decane, n -dodecane, n -tetradecane, and n -hexadecane produced less stable emulsions. Light scattering measurements were performed to analyse the Ostwald ripening phenomenon on diluted oil in water emulsions stabilized with Mesquite gum of n -hexadecane, d -limonene, and orange oil. The averaged hydrodynamic radius showed a linear-like behavior with time except for orange oil drops which kept their size almost constant for more than hundred hours.
Jean-pierre Brunel - One of the best experts on this subject based on the ideXlab platform.
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Sources of water used by natural Mesquite vegetation in a semi arid region of Northern Mexico
Hydrological Sciences Journal, 2009Co-Authors: Jean-pierre BrunelAbstract:Vegetation structure in semi-arid regions of northern Mexico and the southwestern USA has changed dramatically over the last century; shrubs such as Mesquite (Prosopis sp.) have expanded into, and have become dominant in, ecosystems that once supported semi-arid grassland. The upper San Pedro River watershed, which extends from northern Sonora (Mexico) to southeastern Arizona (USA), highlights these changes. Between 1973 and 1992, grasslands decreased by 18% and the total area dominated by Mesquite increased during the same period by 412%. In the areas where the density of Mesquite shrub is medium to high, grass has completely disappeared under the shrub canopy and has been replaced by bare soil. Undoubtedly these cover changes have affected surface-atmosphere interactions by introducing a different partitioning of net available energy into sensible and latent heat flux. At the same time, different root system and root density and plant physiology have introduced a change to the surface water balance, reducing infiltration and increasing runoff. Our study addressed the sources of water used by Mesquite (Prosopis velutina) along a natural gradient from an area of high Mesquite cover with no herbaceous grass cover, to open savanna with high grass cover and widely spaced Mesquite. The presented results from the SALSA 1997 monsoon-season campaign (July-October) show that Mesquite shrubs that have access to both ground-water and surface water use surface water when available, potentially competing with grass for surface water and out-competing grass during successive periods of drought when only groundwater is available
J I Acedocarrillo - One of the best experts on this subject based on the ideXlab platform.
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zeta potential and drop growth of oil in water emulsions stabilized with Mesquite gum
Carbohydrate Polymers, 2006Co-Authors: J I Acedocarrillo, Francisco M. Goycoolea, A Rosasdurazo, R Herreraurbina, Marguerite Rinaudo, Miguel A. ValdezAbstract:Abstract The influence of the nature of the oil phase on the zeta potential and the time course evolution of mean droplet-size of emulsions stabilized with Mesquite gum have been investigated. Mesquite gum-stabilized emulsions of d -limonene, n -decane, n -dodecane, n -tetradecane n -hexadecane, and orange oil were prepared in the range of 9–22% w/w Mesquite gum concentrations to investigate the emulsion stability by analyzing creaming, zeta potential, and drop size distribution. An electrosteric mechanism of stabilization is proposed to explain the long term stability observed for orange oil–water emulsions in the range of 9–22% w/w Mesquite gum concentrations, similar to the one suggested to operate for gum arabic interfaces. Experiments of creaming for the different emulsions, showed that orange oil–water emulsions observed strong stability in time. By contrast, Mesquite gum-stabilized emulsions of d -limonene, n -decane, n -dodecane, n -tetradecane, and n -hexadecane produced less stable emulsions. Light scattering measurements were performed to analyse the Ostwald ripening phenomenon on diluted oil in water emulsions stabilized with Mesquite gum of n -hexadecane, d -limonene, and orange oil. The averaged hydrodynamic radius showed a linear-like behavior with time except for orange oil drops which kept their size almost constant for more than hundred hours.
Francisco M. Goycoolea - One of the best experts on this subject based on the ideXlab platform.
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Classification and physicochemical characterization of Mesquite gum (Prosopis spp.)
Food Hydrocolloids, 2012Co-Authors: Yolanda L. López-franco, Raúl E. Córdova-moreno, Francisco M. Goycoolea, Miguel A. Valdez, Josué Elías Juárez-onofre, Jaime Lizardi-mendozaAbstract:Abstract Under environmental stress conditions, Mesquite trees can excrete a proteinaceous arabinogalactan gum that is similar to gum arabic. Given the application potential of this type of gums a classification procedure for the Mesquite gum is proposed. The main physicochemical properties of the best-quality Mesquite gum were determined and compared with those of gum arabic. Additionally, the composition and molecular changes induced by purification processes were recorded. One batch (157 kg) of Mesquite gum was categorized by subjective assessment into three classes (MGA, MGB and MGC) from high- to low-quality. Approximately 17.5% was classified as top-quality gum. It was found that this class of Mesquite gum has lower humidity, inorganic and tannins content than the other classes, or even than the gum arabic sample used as a reference. All of the Mesquite gum classes have higher protein content and lower intrinsic viscosity than gum arabic. The purification processes were shown to reduce the content of lower molecular weight compounds that modify the interface properties of the gum. The results indicate that the proposed classification method can be used to select Mesquite gum with physicochemical properties comparable to those of commercial gum arabic.
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zeta potential and drop growth of oil in water emulsions stabilized with Mesquite gum
Carbohydrate Polymers, 2006Co-Authors: J I Acedocarrillo, Francisco M. Goycoolea, A Rosasdurazo, R Herreraurbina, Marguerite Rinaudo, Miguel A. ValdezAbstract:Abstract The influence of the nature of the oil phase on the zeta potential and the time course evolution of mean droplet-size of emulsions stabilized with Mesquite gum have been investigated. Mesquite gum-stabilized emulsions of d -limonene, n -decane, n -dodecane, n -tetradecane n -hexadecane, and orange oil were prepared in the range of 9–22% w/w Mesquite gum concentrations to investigate the emulsion stability by analyzing creaming, zeta potential, and drop size distribution. An electrosteric mechanism of stabilization is proposed to explain the long term stability observed for orange oil–water emulsions in the range of 9–22% w/w Mesquite gum concentrations, similar to the one suggested to operate for gum arabic interfaces. Experiments of creaming for the different emulsions, showed that orange oil–water emulsions observed strong stability in time. By contrast, Mesquite gum-stabilized emulsions of d -limonene, n -decane, n -dodecane, n -tetradecane, and n -hexadecane produced less stable emulsions. Light scattering measurements were performed to analyse the Ostwald ripening phenomenon on diluted oil in water emulsions stabilized with Mesquite gum of n -hexadecane, d -limonene, and orange oil. The averaged hydrodynamic radius showed a linear-like behavior with time except for orange oil drops which kept their size almost constant for more than hundred hours.