On the rational design of mesoporous silica humidity sensors

Mesoporous silica is commonly used as matrix for humidity sensors, which operate on the principle of relative humidity-dependent water uptake and read-out by resistive or capacitive means. Although numerous studies have been dedicated to improving the sensing performance, in particular with conductive additives, the effect of pore structure on sensing behaviour has not been systematically investigated so far. Herein, we showcase the effects of pore size and porosity on resistive sensing behaviour in the 0.5-85% relative humidity (RH) range. We employed evaporation-induced self-assembly (EISA) in combination with sol-gel chemistry to fabricate well-defined mesoporous silica thin films with high degree of structural control. Material architectures with pore sizes of 3 to 15 nm and porosities of 40 to 70% were rationally designed by using structure directing agents (SDAs) with increasing molecular weight and tuning the silica to SDA ratio. We found that a combination of pore size of 15 nm and 70% porosity showcases a particularly high sensitivity (~104 times change in resistance) in the measured range, with quick response and recovery times of 3 and 9 seconds, respectively. Across the various sensors, we identified a clear correlation between the pore size and the linear RH sensing range. Sensors with larger mesopores (~15 nm) exhibited higher sensitivity and linear response in the 65 to 85% RH range than sensors with smaller pores (<8 nm). Additionally, increasing the porosity while retaining the pore size, yields better overall sensitivity across the range. Our findings may serve as guidelines for developing broad spectrum high-performance mesoporous sensors and for sensors specifically engineered for optimal operation in specific RH ranges

Ensayos de larga duración. Relación estratégica INTA-CREA, hacia una producción sostenible

Durante la década de los ´90, al tener lugar transformaciones importantes en los sistemas de producción (labranzas, rotación, fertilización), se planteó la necesidad de evaluar los efectos acumulados de esos cambios en el tiempo. Para ello se implementaron 3 estrategias: a) evaluar situaciones que ya habían iniciado estos cambios, muestreando lotes de productores de distintas texturas y prácticas de uso; b) seguimiento de lotes de productores caracterizando la secuencia de cultivos y los efectos que van teniendo lugar sobre distintas propiedades de los suelos y c) establecer módulos experimentales de larga duración donde se contrasten tratamientos que permitan ir monitoreando sus efectos en el tiempo. El primer capítulo, resume parte de la historia y carisma fundacional de quienes fueron “vértebras” en el desarrollo de instituciones como CREA e INTA, principales impulsores de los estudios de larga duración. Presentamos allí parte del “camino transitado” para la puesta en común de prioridades de experimentación buscando respuestas a problemáticas emergentes de los sistemas de producción. Los ensayos de larga duración, fueron priorizados porque constituyen herramientas valiosas para estudiar y entender procesos, mecanismos y sistemas complejos que se expresan en el mediano a largo plazo; permiten generar información básica y aplicada; permiten calibrar y validar modelos de simulación; y dan lugar a la posibilidad de trabajo con enfoque de sistema y a las interacciones inter e intradisciplinarias e institucionales. Los mismos han sido estratégicos en la capacitación y formación de recursos humanos. La presente publicación contiene 12 capítulos con resultados de una serie de ensayos de larga duración, que fueron conducidos durante los últimos 35 años.EEA AnguilFil: Quiroga, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Fernández, Romina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Alvarez, Cristian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural General Pico; Argentin

II Informe técnico de ensayo en establecimiento “La Carlota” Conociendo las limitantes para actuar

Durante los meses marzo-junio 2019, se establecieron ensayos de descompactación en una transecta edafoclimo-secuencia norte-sur de 400 km abarcando desde B Larroude, Trenel, Anguil y Guatraché. Mientras que, en el 2020, se instalaron dos experiencias más, en Trili y Anguil. El presente corresponde a los datos del lote 2 en cercanías de Guatraché, en el establecimiento “La Carlota”, donde se persigue como principal objetivo: Determinar la magnitud y la perdurabilidad de los cambios en las propiedades físico-hídricas de un suelo compactado a través del uso de un descompactador mecánico. Cuantificar el efecto de la inclusión de cultivos de cobertura sobre propiedades físico-hídricas y desarrollo de los sistemas radiculares y rendimiento de los cultivos.EEA AnguilFil: Quiroga, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Fernández, Romina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Alvarez, Cristian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural General Pico; Argentin

Diferentes estrategias para descompactar el suelo. Efecto residual en la infiltración básica

PósterLa compactación es una problemática cada vez más recurrente en la región y genera gran preocupación entre los los productores y colegas de diferentes regiones del país .Sobre un suelo Franco del sur de la planicie con tosca de la Región Semiárida Semiárida Pampeana, se instalaron diferentes tratamientos :-Testigo, sin cultivo de cobertura y sin descompactador mecánico mecánico(T) .-Cultivo de cobertura, utilizado como descompactador biológico (CC).-Descompactador mecánico sin cultivo de cobertura (D) .-Combinación de Descompactador mecánico y cultivo de cobertura (D+CC) .La infiltración se determinó en mayo de 2019 ,octubre de 2019 y septiembre de 2020 através de infiltrómetros de anillo simple .En mayo se midió infiltración de agua en el testigo sin descompactar que refleja la condición inicial .Los resultados se muestran en la Tabla . Es interesante destacar que al año y medio de haber utilizado utilizado un subsolador para descompactar, ,el valor de IB es similar entre D+CC y CC .Estos resultados preliminares, se seguirán midiendo y analizando durante 2021 y2022 .EEA AnguilFil: Fernandez, Romina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Alvarez, Cristian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural General Pico; ArgentinaFil: Quiroga, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentina. Universidad Nacional de La Pampa. Facultad de Agronomía; Argentin

On the Rational Design of Mesoporous Silica Humidity Sensors

Mesoporous silica is commonly used as matrix for humidity sensors which operate on the principle of relative humidity (RH)-dependent water uptake and read-out by resistance (R) monitoring. Although numerous studies have been dedicated to improving sensitivity with conductive additives, the role of the pore architecture on the sensing behavior has not been systematically investigated so far. Herein, the effects of pore size and porosity on resistive sensing performance in the 0.5–85% RH range are showcased. Across various sensors, a clear correlation is identified between mesopore size and linear RH sensing range. Sensors with larger pores (≈15 nm) exhibit linear response in the 65 to 85% RH range with larger slope (ΔlogR/ΔRH) than sensors with smaller pores (<8 nm). Additionally, increasing porosity while retaining pore size, yields better overall sensor performance across the 15–85% RH range. In particular, a combination of pore size around 15 nm and porosity of 70% showcased a large resistance versus RH response (R0/R ≈ 10000) in the measured range, with quick response and recovery times of 3 and 9 seconds, respectively. These findings may serve as guidelines for developing broad spectrum high performance mesoporous sensors and for sensors specifically engineered to operate in specific RH ranges

Glucose Oxidase Loading in Ordered Porous Aluminosilicates: Exploring the Potential of Surface Modification for Electrochemical Glucose Sensing

Enzymatic electrochemical sensors have become the leading glucose detection technology due to their rapid response, affordability, portability, selectivity, and sensitivity. However, the performance of these sensors is highly dependent on the surface properties of the electrode material used to store glucose oxidase and its ability to retain enzymatic activity under variable environmental conditions. Mesoporous thin films have recently attracted considerable attention as promising candidates for enzyme storage and activity preservation due to their well-defined nanoarchitecture and tunable surface properties. Herein, we systematically compare pathways for the immobilization of glucose oxidase (GOx) and their effectiveness in electrochemical glucose sensing, following modification protocols that lead to the electrostatic attraction (amino functionalization), covalent bonding (aldehyde functionalization), and electrostatic repulsion (oxygen plasma treatment) of the ordered porous aluminosilicate-coated electrodes. By direct comparison using a quartz crystal microbalance, we demonstrate that glucose oxidase can be loaded in a nanoarchitecture with a pore size of ∼50 nm and pore interconnections of ∼35 nm using the native aluminosilicate surface, as well as after amino or aldehyde surface modification, while oxygen plasma exposure of the native surface inhibits glucose oxidase loading. Despite a variety of routes for enzyme loading, quantitative electrochemical glucose sensing between 0 and 20 mM was only possible when the porous surface was functionalized with amino groups, which we relate to the role of surface chemistry in accessing the underlying substrate. Our results highlight the impact of rational surface modification on electrochemical biosensing performance and demonstrate the potential of tailoring porous nanoarchitecture surfaces for biosensing applications

Opportunities for isoporous membranes in the manufacture of genomic medicines

Viral and non-viral vectors have revolutionised in the last 5 years the approaches to tackling pandemics, cancers and genetic diseases. The intrinsic properties of these vectors present new separation challenges to their manufacture in terms of both the process-related impurities to be removed and the complex labile nature of the target products. These characteristics make them susceptible to heterogeneity and the formation of product-related impurities. Conventional polyethersulfone membrane filters used for sterile filtration and ultrafiltration of viral vectors and lipid nanoparticles can display limited selectivity and cause product losses. To address these challenges, novel membrane materials and fabrication techniques to overcome the boundary of selectivity-permeability performance have become of interest. Isoporous membranes with well-defined pore size and pore dispersity at the nano-scale show promising separation performance but have only been demonstrated at small scales to date. This review summarises the decision process for the development of new membrane candidates for vector manufacturing in genomic medicine, including membranes fabricated by lithography, track-etched membranes, anodic aluminium oxide (AAO) membranes and self-assembled block copolymer membranes. By comparing these membranes to existing commercially available products, the possible advantages presented by novel materials and fabrication approaches are identified