18 research outputs found
Geometric maximal operators and BMO on product bases
We consider the problem of the boundedness of maximal operators on BMO on
shapes in . We prove that for bases of shapes with an engulfing
property, the corresponding maximal function is bounded from BMO to BLO,
generalising a known result of Bennett for the basis of cubes. When the basis
of shapes does not possess an engulfing property but exhibits a product
structure with respect to lower-dimensional shapes coming from bases that do
possess an engulfing property, we show that the corresponding maximal function
is bounded from BMO to a space we define and call rectangular BLO
Alternative Eco-Friendly Methods in the Control of Post-Harvest Decay of Tropical and Subtropical Fruits
The effectiveness on several fruits by the application of alternative methods against fungi is summarized in the present chapter. Several investigations have reported the efficacy of these technologies for controlling fungal infections. Currently, high post-harvest loses have been reported due to several factors such as inefficient management, lack of training for farmers, and problems with appropriate conditions for storage of fruits and vegetables. Even now, in many countries, post-harvest disease control is led by the application of chemical fungicides. However, in this time, awareness about fungi resistance, environmental, and health issues has led to the research of eco-friendly and effective alternatives for disease management. The pathogen establishment on fruits can be affected by the application of GRAS compounds like chitosan, essential oils, salts, among others; besides, their efficacy can be enhanced by their combination with other technologies like ultrasound. Thus, the applications of these alternatives are suitable approaches for post-harvest management of fruits
Petrophysical and mechanical rock property database of the Los Humeros and Acoculco geothermal fields (Mexico)
Petrophysical and rock mechanical properties are key parameters for the characterization of the deep subsurface in different disciplines such as geothermal heat extraction, petroleum reservoir engineering or mining, are commonly used for the interpretation of geophysical data and the parameterization of numerical models and as thus are the basis for economic reservoir assessment. However, detailed information regarding these properties for each target horizon are often scarce, inconsistent or spread over multiple publications. Thus, subsurface models are often populated with generalized or assumed values resulting in high uncertainty. Furthermore, diagenetic, metamorphic and hydrothermal processes significantly affect the physiochemical and mechanical properties often leading to high variability. A sound understanding of the controlling factors is needed to identify statistical and causal relationships between the properties as basis for a profound reservoir assessment and modelling.
Within the scope of the GEMex project (EU-H2020, GA Nr. 727550), which aims to develop new transferable exploration and exploitation approaches for super-hot unconventional geothermal systems, a new workflow was applied to overcome the gap of knowledge of the reservoir properties. Two caldera complexes located in the northeastern Trans Mexican Volcanic Belt - the Acoculco and Los Humeros caldera - were selected as demonstration sites. The Los Humeros geothermal system is steam dominated and has been exploited since the 1990’s with 65 wellbores (28 still producing). With temperatures above 380 °C, the system is characterized as a super-hot geothermal system. The geothermal system in Acoculco (presently consisting of two exploration wells) is characterized by temperatures of approximately 300 °C at a depth of about 2 km. It contains almost no fluids, even though a well-developed fracture network exists in the study area. Therefore, the system serves as a demonstration site for the development of an enhanced geothermal system.
The workflow starts with outcrop analogue and reservoir core sample studies in order to define and characterize the properties of all key units from the basement to the cap rock as well as their mineralogy and geochemistry. This allows the identification of geological heterogeneities on different scales (outcrop analysis, representative rock samples, thin sections and chemical analysis) enabling a profound reservoir property prediction.
More than 340 rock samples were taken from representative outcrops inside of the Los Humeros and Acoculco calderas, the surrounding areas and from exhumed ‘fossil systems’ in Las Minas and Zacatlán. Additionally, 66 core samples from 16 wells of the Los Humeros geothermal field were obtained. Samples were analyzed for particle and bulk density, porosity, permeability, thermal conductivity, thermal diffusivity, heat capacity, as well as ultra-sonic wave velocities, magnetic susceptibility and electric resistivity. Afterwards destructive rock mechanical tests (point load tests, uniaxial and triaxial tests) were conducted to determine tensile strength, uniaxial compressive strength, Young’s modulus, poisson ratio, bulk modulus, shear modulus, fracture toughness, cohesion and friction angle. In addition, XRD and XRF analyses were performed on 131 samples to provide information about the mineral assemblage, bulk geochemistry and the intensity of hydrothermal alteration.
An extensive rock property database was created comprising 34 parameters determined on more than 2160 plugs. More than 31,000 data points were compiled covering volcanic, sedimentary, metamorphic and igneous rocks from different ages (Jurassic to Holocene), thus facilitating a wide field of applications regarding resource assessment, modeling and statistical analyses.V1.
Petrophysical and mechanical rock property database of the Los Humeros and Acoculco geothermal fields (Mexico)
Petrophysical and rock mechanical properties are key parameters for the characterization of the deep subsurface in different disciplines such as geothermal heat extraction, petroleum reservoir engineering or mining, are commonly used for the interpretation of geophysical data and the parameterization of numerical models and as thus are the basis for economic reservoir assessment. However, detailed information regarding these properties for each target horizon are often scarce, inconsistent or spread over multiple publications. Thus, subsurface models are often populated with generalized or assumed values resulting in high uncertainty. Furthermore, diagenetic, metamorphic and hydrothermal processes significantly affect the physiochemical and mechanical properties often leading to high variability. A sound understanding of the controlling factors is needed to identify statistical and causal relationships between the properties as basis for a profound reservoir assessment and modelling.
Within the scope of the GEMex project (EU-H2020, GA Nr. 727550), which aims to develop new transferable exploration and exploitation approaches for super-hot unconventional geothermal systems, a new workflow was applied to overcome the gap of knowledge of the reservoir properties. Two caldera complexes located in the northeastern Trans Mexican Volcanic Belt - the Acoculco and Los Humeros caldera - were selected as demonstration sites. The Los Humeros geothermal system is steam dominated and has been exploited since the 1990’s with 65 wellbores (28 still producing). With temperatures above 380 °C, the system is characterized as a super-hot geothermal system. The geothermal system in Acoculco (presently consisting of two exploration wells) is characterized by temperatures of approximately 300 °C at a depth of about 2 km. It contains almost no fluids, even though a well-developed fracture network exists in the study area. Therefore, the system serves as a demonstration site for the development of an enhanced geothermal system.
The workflow starts with outcrop analogue and reservoir core sample studies in order to define and characterize the properties of all key units from the basement to the cap rock as well as their mineralogy and geochemistry. This allows the identification of geological heterogeneities on different scales (outcrop analysis, representative rock samples, thin sections and chemical analysis) enabling a profound reservoir property prediction.
More than 340 rock samples were taken from representative outcrops inside of the Los Humeros and Acoculco calderas, the surrounding areas and from exhumed ‘fossil systems’ in Las Minas and Zacatlán. Additionally, 66 core samples from 16 wells of the Los Humeros geothermal field were obtained. Samples were analyzed for particle and bulk density, porosity, permeability, thermal conductivity, thermal diffusivity, heat capacity, as well as ultra-sonic wave velocities, magnetic susceptibility and electric resistivity. Afterwards destructive rock mechanical tests (point load tests, uniaxial and triaxial tests) were conducted to determine tensile strength, uniaxial compressive strength, Young’s modulus, poisson ratio, bulk modulus, shear modulus, fracture toughness, cohesion and friction angle. In addition, XRD and XRF analyses were performed on 131 samples to provide information about the mineral assemblage, bulk geochemistry and the intensity of hydrothermal alteration.
An extensive rock property database was created comprising 34 parameters determined on more than 2160 plugs. More than 31,000 data points were compiled covering volcanic, sedimentary, metamorphic and igneous rocks from different ages (Jurassic to Holocene), thus facilitating a wide field of applications regarding resource assessment, modeling and statistical analyses.V1.
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The Miocene Tatatila–Las Minas IOCG skarn deposits (Veracruz) as a result of adakitic magmatism in the Trans-Mexican Volcanic Belt - Los depósitos de tipo skarn IOCG miocénicos de Tatatila–Las Minas (Veracruz) como resultado del magmatismo adakítico de la Faja Volcánica Trans-Mexicana
The Cu- and Au-rich Tatatila–Las Minas IOCG skarn deposits in Veracruz (central-east Mexico) are circumscribed to the earliest stages of the Trans-Mexican Volcanic Belt (TMVB) and stand for a metallogenic province directly linked to its tectonomagmatic dynamics. This is the first well-documented case for such metallogenic province. These deposits were formed as skarns between rocks of the Mesozoic carbonate series and Miocene intermediate to acid hypabyssal rocks. New U-Pb zircon and 40Ar/39Ar ages provide evidence for four epochs of magmatic activity in the area: (1) early Permian (Artinskian), in association with the Paleozoic basement, (2) late Oligocene to early Miocene suite of pre-TMVB intrusive rocks, (3) middle to late Miocene suite of early TMVB-related intrusive rocks, and (4) Pliocene intrusive and extrusive rocks of the TMVB, possibly associated with the Los Humeros post-caldera stage. The obtained ages range between 24.60 ± 1.10 and 19.04 ± 0.69 Ma for stage 2, and between 16.34 ± 0.20 and 13.92 ± 0.22 Ma for stage 3. Stage 2 corresponds to a magmatic stage unheard of in the area, until this study. Only stage 3 rocks are associated with the IOCG skarn mineralization, with retrograde stages dated at 12.44 ± 0.09 (chromian muscovite, phyllic association) and 12.18 ± 0.21 Ma (zircon, potassic association). Therefore, the ages of stage-3 intrusive rocks are interpreted to date the formation of e prograde skarn associations (mostly ~15.4 to <14 Ma). The petrogenetic affinity of stage-2 and stage-3 rocks is about the same—the main difference has to do with higher Y and Yb contents in stage-3 rocks (although no affinity with within-plate granites was found), which is suggestive of an interaction of their parental magmas with alkaline magmas that most likely belong to the conterminous and contemporaneous Eastern Mexico Alkaline Province. Petrological indicators (elemental and isotopic) in Cenozoic rocks consistently point to intermediate to acid, metaluminous, I- and S-type rocks that were emplaced in a subduction-related continental arc, within the medium- to high-potassium calc-alkaline series, with high-silica adakitic signatures due associated to deep-sourced magmas that underwent crustal contamination to some degree. The various possible sources for the magmas with adakitic signature in this context can be narrowed down to two of them that are not mutually exclusive: adakitic derived from subducted slab melting and melting-assimilation-storage-homogenization (MASH)-derived adakites. Both sources are, in principle, capable of generating magmas that would eventually produce magmatic-hydrothermal mineralizing systems with an associated variety of ore deposit types, including IOCG. Also, both possible sources for adakites are compatible with the renewed steepening of the subducted slab after a period of flat subduction, for the earliest stage in the evolution of the TMVB. © 2020. All Rights Reserved.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Jefa del Departamento de Matemáticas Consejo Editorial del Departamento de Matemáticas Dr. Oscar Vega Amaya Coordinador General
ii COMITÉ ORGANIZADO
Petrophysical and mechanical rock property database of the Los Humeros and Acoculco geothermal fields (Mexico)
Petrophysical and mechanical rock properties are key parameters for the characterization of the deep subsurface in different disciplines such as geothermal heat extraction, petroleum reservoir engineering or mining. They are commonly used for the interpretation of geophysical data and the parameterization of numerical models and thus are the basis for economic reservoir assessment. However, detailed information regarding petrophysical and mechanical rock properties for each relevant target horizon is often scarce, inconsistent or distributed over multiple publications. Therefore, subsurface models are often populated with generalized or assumed values resulting in high uncertainties. Furthermore, diagenetic, metamorphic and hydrothermal processes significantly affect the physiochemical and mechanical properties often leading to high geological variability. A sound understanding of the controlling factors is needed to identify statistical and causal relationships between the properties as a basis for a profound reservoir assessment and modeling. Within the scope of the GEMex project (EU H2020, grant agreement no. 727550), which aims to develop new transferable exploration and exploitation approaches for enhanced and super-hot unconventional geothermal systems, a new workflow was applied to overcome the gap of knowledge of the reservoir properties. Two caldera<span idCombining double low line"page572"/> complexes located in the northeastern Trans-Mexican Volcanic Belt - the Acoculco and Los Humeros caldera - were selected as demonstration sites. The workflow starts with outcrop analog and reservoir core sample studies in order to define and characterize the properties of all key units from the basement to the cap rock as well as their mineralogy and geochemistry. This allows the identification of geological heterogeneities on different scales (outcrop analysis, representative rock samples, thin sections and chemical analysis) enabling a profound reservoir property prediction. More than 300 rock samples were taken from representative outcrops inside the Los Humeros and Acoculco calderas and the surrounding areas and from exhumed "fossil systems" in Las Minas and Zacatlán. Additionally, 66 core samples from 16 wells of the Los Humeros geothermal field and 8 core samples from well EAC1 of the Acoculco geothermal field were collected. Samples were analyzed for particle and bulk density, porosity, permeability, thermal conductivity, thermal diffusivity, and heat capacity, as well as ultrasonic wave velocities, magnetic susceptibility and electric resistivity. Afterwards, destructive rock mechanical tests (point load tests, uniaxial and triaxial tests) were conducted to determine tensile strength, uniaxial compressive strength, Young's modulus, Poisson's ratio, the bulk modulus, the shear modulus, fracture toughness, cohesion and the friction angle. In addition, X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses were performed on 137 samples to provide information about the mineral assemblage, bulk geochemistry and the intensity of hydrothermal alteration. An extensive rock property database was created (Weydt et al., 2020; <a hrefCombining double low line"https://doi.org/10.25534/tudatalib-201.10">https://doi.org/10.25534/tudatalib-201.10</a>), comprising 34 parameters determined on more than 2160 plugs. More than 31 000 data entries were compiled covering volcanic, sedimentary, metamorphic and igneous rocks from different ages (Jurassic to Holocene), thus facilitating a wide field of applications regarding resource assessment, modeling and statistical analyses..Reservoir Engineerin
Complex interactions between nicotine and resveratrol in the Drosophila melanogaster wing spot test
Nicotine (NIC) and resveratrol (RES) are chemicals in tobacco and wine, respectively, that are widely consumed concurrently worldwide. NIC is an alkaloid known to be toxic, addictive and to produce oxidative stress, while RES is thought of as an antioxidant with putative health benefits. Oxidative stress can induce genotoxic damage, yet few studies have examined whether NIC is genotoxic in vivo. In vitro studies have shown that RES can ameliorate deleterious effects of NIC. However, RES has been reported to have both antioxidant and pro-oxidant effects, and an in vivo study reported that 0.011 mM RES was genotoxic. We used the Drosophila melanogaster wing spot test to determine whether NIC and RES, first individually and then in combination, were genotoxic and/or altered the cell division. We hypothesized that RES would modulate NIC's effects. NIC was genotoxic in the standard (ST) cross in a concentration-independent manner, but not genotoxic in the high bioactivation (HB) cross. RES was not genotoxic in either the ST or HB cross at the concentrations tested. We discovered a complex interaction between NIC and RES. Depending on concentration, RES was protective of NIC's genotoxic damage, RES had no interaction with NIC, or RES had an additive or synergistic effect, increasing NIC's genotoxic damage. Most NIC, RES, and NIC/RES combinations tested altered the cell division in the ST and HB crosses. Because we used the ST and HB crosses, we demonstrated that genotoxicity and cell division alterations were modulated by the xenobiotic metabolism. These results provide evidence of NIC's genotoxicity in vivo at specific concentrations. Moreover, NIC's genotoxicity can be modulated by its interaction with RES in a complex manner, in which their interaction can lead to either increasing NIC's damage or protecting against it. © 2022 The Author(s)Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]