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The fate of rice crop residues and context-dependent greenhouse gas emissions: Model-based insights from Eastern India

Sonam Sherpa virender kumar Andrew Mcdonald (2024, [Artículo])

Crop residue burning is a common practice in many parts of the world that causes air pollution and greenhouse gas (GHG) emissions. Regenerative practices that return residues to the soil offer a ‘no burn’ pathway for addressing air pollution while building soil organic carbon (SOC). Nevertheless, GHG emissions in rice-based agricultural systems are complex and difficult to anticipate, particularly in production contexts with highly variable hydrologic conditions. Here we predict long-term net GHG fluxes for four rice residue management strategies in the context of rice-wheat cropping systems in Eastern India: burning, soil incorporation, livestock fodder, and biochar. Estimations were based on a combination of Tier 1, 2, and 3 modelling approaches, including 100-year DNDC simulations across three representative soil hydrologic categories (i.e., dry, median, and wet). Overall, residue burning resulted in total direct GHG fluxes of 2.5, 6.1, and 8.7 Mg CO2-e in the dry, median, and wet hydrologic categories, respectively. Relative to emissions from burning (positive values indicate an increase) for the same dry to wet hydrologic categories, soil incorporation resulted in a −0.2, 1.8, or 3.1 Mg CO2-e change in emissions whereas use of residues for livestock fodder increased emissions by 2.0, 2.1, or 2.3 Mg CO2-e. Biochar reduced emissions relative to burning by 2.9 Mg CO2-e in all hydrologic categories. This study showed that the production environment has a controlling effect on methane and, therefore, net GHG balance. For example, wetter sites had 2.8–4.0 times greater CH4 emissions, on average, than dry sites when rice residues were returned to the soil. To effectively mitigate burning without undermining climate change mitigation goals, our results suggest that geographically-target approaches should be used in the rice-based systems of Eastern India to incentivize the adoption of regenerative ‘no burn’ residue management practices.

Soil Carbon Rice Residue Burning Life Cycle Assessment CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA SOIL CARBON RICE LIFE CYCLE GREENHOUSE GASES CLIMATE CHANGE

Fabrication of PVDF/PMMA Polymer for Sustainable Energy Harvesting .

JOSE RAYMUNDO LEPPE NEREY FERNANDO ZENAIDO SIERRA ESPINOSA MIGUEL ANGEL BASURTO PENSADO JOSE ALFREDO RODRIGUEZ RAMIREZ (2023, [Artículo])

The synthesis of blends that combine properties of two or more polymeric materials is increasingly investigated due to the versatility of the synthesis and its growing potential for many applications, including sustainability. Their characteristics are defined mainly by the synthesis conditions. Therefore, this paper details the synthesis process of easy-to-handle films using mixing method. The procedures and drawbacks found during the preparation of composite films are described. Polymeric compounds formed by the mixture of polyvinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA) are addressed, varying the concentration, and evaluating their impact on the piezoelectric capacity. Films were formed through the spin-coating technique and characterized by optical and holographic microscopes. The results showed that composites with a concentration of 50 wt.% or larger of PVDF in the blend acquire a morphology with a granular appearance, however at lower concentrations they present a homogeneous morphology similar to that of PMMA. A homogeneous distribution of PVDF in the PMMA stands out. However, excessive contents of PMMA are associated to peaks and non-uniformities detected like multicolored regions by digital holography. Controlled strength-strain laboratory tests allowed to evaluate the film blends performance. The results indicate noticeable improvements in voltage output for a composition 70wt% PVDF and 30 wt% PMMA.

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS Polymer blends, Power generation, Energy harvesting, Piezoelectricity,

Novel Low-cost Energy Harvester Based on anArrangement of Piezoelectric Actuators

CARLOS ANDRES FERRARA BELLO Margarita Tecpoyotl Torres (2024, [Artículo])

This article provides the design, modeling, fabrication, and testing of an energy

harvester from mechanical vibrations, based on a piezoelectric material. This device

works on the principle of piezoelectric transduction, i.e., when mechanically

deformed, it generates electrical energy due to vibrations. The piezoelectric material

used in the fabrication was Lead Zirconate Titanate (PZT), and brass as structural

base. In addition, finite element models were performed to predict the frequency of

the first vibration mode of the device, and experimental setups for validation. The

resonance frequency of the numerical model and the one obtained experimentally (19

Hz) show a deviation of 5.03% respectively. The generated power is 0.202 mW enough

to power low power devices such as basic calculators, wristwatches, and transistors, among others.

En este artículo se presenta el diseño, modelado, fabricación y pruebas de un cosechador de energía proveniente de vibraciones mecánicas, basado en un material piezoeléctrico. Este dispositivo trabaja bajo el principio de transducción piezoeléctrica, es decir que, al deformarse mecánicamente, debido a las vibraciones genera energía eléctrica. El material piezoeléctrico usado en la fabricación fue Zirconato Titanato de Plomo (PZT), y latón como base estructural. Además, se realizaron modelos de elemento finito para predecir la frecuencia del primer modo de vibración del dispositivo, y arreglos experimentales para su validación. La frecuencia de resonancia del modelo numérico y la obtenida experimentalmente (19 Hz) muestran una desviación de 5.03% respectivamente. La potencia generada es de0.202 mW suficiente para alimentar dispositivos de bajo consumo, tales como calculadoras básicas, relojes de pulsera y transistores, entre otros.

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS Finite Element Method, low-energy devices, vibration, piezoelectric transducer

Análisis de la disminución de emisiones de CO2 en el acondicionamiento de un espacio con un sistema pasivo

JULIO CESAR BRITO REYNA (2023, [Tesis de maestría])

En el contexto global de la dependencia de fuentes de energía fósil en el modelo energético actual, la electricidad desempeña un papel fundamental en el crecimiento y desarrollo de las ciudades. Derivado del consumo excesivo de estas fuentes, se genera la presencia de fenómenos como el Cambio Climático, evidenciando así el uso generalizado de sistemas de climatización en edificaciones durante la temporada de verano en áreas geográficas con climas tropicales y cálidos.

El trabajo presenta un estudio comparativo anual de los impactos ambientales de dos sistemas de climatización en un espacio construido previamente: un sistema activo y un sistema pasivo. El estudio se llevó a cabo mediante la simulación de procesos sustentables utilizando el software TRNSYS® y también se evaluaron los indicadores de Calentamiento Global, Agotamiento de la Capa de Ozono y Agotamiento de combustibles fósiles, por mencionar a algunos, utilizando la metodología de Análisis de Ciclo de Vida (ACV) en el software OpenLCA. Los resultados demuestran una reducción de los impactos ambientales mediante el uso de elementos pasivos en comparación con el uso de dos aires acondicionados y su consumo eléctrico, evitando una huella de carbono de un 98% en su etapa de construcción y hasta en un 100% en su etapa de operación.

Este estudio contribuye al conocimiento sobre la importancia de implementar estrategias de climatización pasiva en edificaciones existentes como una alternativa sostenible y de bajo impacto ambiental. Los hallazgos respaldan la necesidad de promover soluciones más eficientes y respetuosas con el medio ambiente en el sector de la climatización, en línea con la transición hacia un modelo energético más sostenible y la mitigación del Cambio Climático.

In the global context of dependence on fossil fuel energy sources in the current energy model, electricity plays a crucial role in the growth and development of cities. This is evident in the widespread use of air conditioning systems in buildings during the summer season in areas with tropical and warm climates.

This work presents an annual comparative study of the environmental impacts of two cooling systems in a pre-existing space: the active system and the passive system. The study was carried out through the simulation of sustainable processes using the TRNSYS® software, and various indicators such as Global Warming Potential (GWP100a), Ozone Depletion Potential, and Fossil Fuel Depletion were evaluated using the Life Cycle Assessment (LCA) methodology in the OpenLCA software. The results demonstrate a reduction in environmental impacts through the use of passive elements compared to the use of two air conditioning units and their electricity consumption, avoiding a carbon footprint of 98% during its construction stage and up to 100% during its operational stage

This study contributes to the understanding of the importance of implementing passive cooling strategies in existing buildings as a sustainable and low-impact alternative. The findings support the need to promote more efficient and environmentally-friendly solutions in the cooling sector, in line with the transition towards a more sustainable energy model and the mitigation of Climate Change.

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS Energía electrica, climatización, sustentabilidad, Cambio Climático Electricity, cooling, sustainability, Climate Change