455 research outputs found
Large distance expansion of Mutual Information for disjoint disks in a free scalar theory
We compute the next-to-leading order term in the long-distance expansion of
the mutual information for free scalars in three space-time dimensions. The
geometry considered is two disjoint disks separated by a distance between
their centers. No evidence for non-analyticity in the R\'enyi parameter for
the continuation in the next-to-leading order term is found.Comment: 15 pages, This version contains few extra references, some technical
material has been move to appendices, and other minor modifications to match
with the version accepted for publicatio
Ergodicity and Conservativity of products of infinite transformations and their inverses
We construct a class of rank-one infinite measure-preserving transformations
such that for each transformation in the class, the cartesian product
of the transformation with itself is ergodic, but the product
of the transformation with its inverse is not ergodic. We also
prove that the product of any rank-one transformation with its inverse is
conservative, while there are infinite measure-preserving conservative ergodic
Markov shifts whose product with their inverse is not conservative.Comment: Added references and revised some arguments; removed old section 6;
main results unchange
Influencia del aditivo Sika 1 para mejorar la impermeabilidad del concreto f´c = 210 kg/cm2 en suelos con presencia de nivel freático en la urbanización los Huertos de Villa Chorrillos, Lima, 2019
En la presente investigación titulada “Influencia del aditivo Sika 1 para mejorar la
impermeabilidad del concreto f´c = 210 kg/cm2 en suelos con presencia de nivel freático en
la Urbanización los Huertos de Villa Chorrillos, Lima, 2019”, tuvo como objetivo analizar
cómo predomina el aditivo sika 1 en la mejora de la impermeabilidad del concreto F´C= 210
KG/CM2. Elaborado con cemento portland tipo V.
El diseño de investigación que se desarrollo fue el método de investigación Cuantitativa de
tipo aplicada y de diseño experimental. El desarrollo de la metodología fue en diseñar 4
tipos de mezcla de concreto con una resistencia de 210 f´c= kg/cm2 con aditivo Sika 1 con
una dosifición de 2.35%, 3.53%, 4.71% y 5.88% con respecto con el peso del cemento. Para
determinar la reducción de la permeabilidad se desarrolló en base de la morma NTP 339.187
para determinar la densidad y vacíos del concreto permeable en estado endurecido, la NTP
339.035 para determinar el asentamiento del concreto en estado fresco y la NTP 330.034
para determina la resistencia mediante la prueba de compresión en probetas cilíndricas.
Los resultados mostraron como predomina el aditivo Sika 1 en la mejora de la permeabilidad
del concreto f´c =210 kg/cm2 en función de la dosificación establecida en los diseños de
mezcla. Asiéndolo un concreto más trabajable, impermeable y duradero
Investigating Membrane Material Alternatives for Air Revitalization in Space
Recently, NASA’s ultimate goal has been to launch a crewed Mars mission. However, the current system used for carbon dioxide (CO2) removal in air revitalization in the International Space Station (ISS) is not equipped to handle beyond low-earth-orbit missions. The Carbon Dioxide Removal Assembly (CDRA) is a complex system that relies heavily on sorbent materials and faces challenges in reliability, energy efficiency, and material degradation. Although the CDRA has operated well in the ISS for the past two decades, health effects from high CO2 levels are amongst the most common complaints from and challenges for astronauts. Recent developments in membrane technology prove to be a promising alternative to sorbent-based systems for CO2 removal. Maintaining high selectivity for CO2 with a reasonable permeability, at such low partial pressures and in the presence of water, is among the main challenges of using membranes in this application. In this work, we have created a membrane-based model with appropriate conditions to identify the membrane technology for this application. We expect to determine a working range of critical parameters such as permeability, selectivity, and membrane area for successful CO2 separation. We will also be comparing the thermodynamic efficiency of a membrane-based process to that of the CDRA to pin-point areas of improvement
Enhanced surface interaction of water confined in hierarchical porous polymers induced by hydrogen bonding
Hierarchical porous polymer systems are increasingly applied to catalysis, bioengineering, or separation technology because of the versatility provided by the connection of mesopores with percolating macroporous structures. Nuclear magnetic resonance (NMR) is a suitable technique for the study of such systems as it can detect signals stemming from the confined liquid and translate this information into pore size, molecular mobility, and liquid−surface interactions. We focus on the properties of water confined in macroporous polymers of ethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate [poly- (EGDMA-co-HEMA)] with different amounts of cross-linkers, in which a substantial variation of hydroxyl groups is achieved. As soft polymer scaffolds may swell upon saturation with determined liquids, the use of NMR is particularly important as it measures the system in its operational state. This study combines different NMR techniques to obtain information on surface interactions of water with hydrophilic polymer chains. A transition from a surface-induced relaxation in which relaxivity depends on the pore size to a regime where the organic pore surface strongly restricts water diffusion is observed. Surface affinities are defined through the molecular residence times near the network surface.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Stapf, Siegfried. Technische Universität Ilmenau; AlemaniaFil: Mattea, Carlos. Technische Universität Ilmenau; AlemaniaFil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Acosta, Rodolfo Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin
Spatially Resolved Monitoring of Drying of Hierarchical Porous Organic Networks
Evaporation kinetics of water confined in hierarchal polymeric porous media is studied by low field nuclear magnetic resonance (NMR). Systems synthesized with various degrees of cross-linker density render networks with similar pore sizes but different response when soaked with water. Polymeric networks with low percentage of cross-linker can undergo swelling, which affects the porosity as well as the drying kinetics. The drying process is monitored macroscopically by single-sided NMR, with spatial resolution of 100 μm, while microscopic information is obtained by measurements of spin?spin relaxation times (T2). Transition from a funicular to a pendular regime, where hydraulic connectivity is lost and the capillary flow cannot compensate for the surface evaporation, can be observed from inspection of the water content in different sample layers. Relaxation measurements indicate that even when the larger pore structures are depleted of water, capillary flow occurs through smaller voids.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Gomez, Cesar Gerardo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo En Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo En Ingeniería de Procesos y Química Aplicada.; ArgentinaFil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Stapf, Siegfried. Ilmenau University of Technology; AlemaniaFil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Mattea, Carlos. Ilmenau University of Technology; AlemaniaFil: Acosta, Rodolfo Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin
Risk behaviors and reasons for not getting tested for HIV among men who have sex with men in Peru
Electrochemical immunosensing of low-density lipoprotein based on sol-gel encapsulation
Lipoprotein monitoring is desirable in the management of medical conditions such as atherosclerotic cardiovascular disease and coronary artery disease, in which controlling the concentration of these chylomicrons is crucial. Current clinical methods are complex and present poor reproducibility between laboratories. For these reasons, recent guidelines discard the assessment of low-density lipoprotein cholesterol (LDL-C) as a routine analysis during lipid-lowering therapies. Concerning the importance of monitoring this parameter, the authors present an electrochemical immunosensor constructed from a simple and easy-to-reproduce platform that allows detecting and quantifying LDL nanoparticles directly from human serum samples. The performance of the biosensor was studied by scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The biosensing platform displays good stability and linearity between 30 mg dL-1 and 135 mg dL-1 with a detection limit of 20 mg dL-1. The proposed biosensor can be easily employed for monitoring LDL concentration in clinical treatments
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