Chemical recycling of plastics assisted by microwave multi-frequency heating

Handling plastic waste through recycling allows extending the life of polymeric materials, avoiding recurrence to incineration or landfilling. In contrast with traditional mechanical recycling technologies, chemical recycling enables the obtention of the virgin monomers by means of depolymerisation to create new polymers with the same mechanical and thermal properties as the originals. Research presented in this paper is part of the polynSPIRE project (Horizon 2020 European funding programme) and develops and scales-up a heated reactor to carry out the depolymerisation of polyamide-6 (PA6), polyamide-6, 6 (PA66) and polyurethane (PU) using microwave (MW) technology as the heating source. The purpose is to design and optimize a MW reactor using up to eight ports emitting electromagnetic waves. Finite element method (FEM) simulation and optimisation are used to design the reactor, considering as parameters the data obtained from experimental dielectric testing and lab-scale characterisation of the processes and materials studied. Two different COMSOL Multiphysics modules are involved in this work: Radio Frequency (RF) and Chemical Reaction Engineering (RE), to simulate the reactor cavity using two frequency levels (915 MHz and 2.45 GHz) with a power level of 46 kW, and the chemical depolymerisation process, respectively. A sensitivity study has been performed on key parameters such as the frequency, the number of ports, and position inside the reactor to consolidate the final design. It is expected that these results assist in the design and scale-up of microwave technology for the chemical recycling of plastics, and for the large-scale deployment of this sustainable recovery alternative. © 2021 The Author

COVID-19 vaccine acceptance and hesitancy in low- and middle-income countries

Widespread acceptance of COVID-19 vaccines is crucial for achieving sufficient immunization coverage to end the global pandemic, yet few studies have investigated COVID-19 vaccination attitudes in lower-income countries, where large-scale vaccination is just beginning. We analyze COVID-19 vaccine acceptance across 15 survey samples covering 10 low- and middle-income countries (LMICs) in Asia, Africa and South America, Russia (an upper-middle-income country) and the United States, including a total of 44,260 individuals. We find considerably higher willingness to take a COVID-19 vaccine in our LMIC samples (mean 80.3%; median 78%; range 30.1 percentage points) compared with the United States (mean 64.6%) and Russia (mean 30.4%). Vaccine acceptance in LMICs is primarily explained by an interest in personal protection against COVID-19, while concern about side effects is the most common reason for hesitancy. Health workers are the most trusted sources of guidance about COVID-19 vaccines. Evidence from this sample of LMICs suggests that prioritizing vaccine distribution to the Global South should yield high returns in advancing global immunization coverage. Vaccination campaigns should focus on translating the high levels of stated acceptance into actual uptake. Messages highlighting vaccine efficacy and safety, delivered by healthcare workers, could be effective for addressing any remaining hesitancy in the analyzed LMICs.Publisher PDFPeer reviewe

El laberinto de la autonomía indígena en el Ecuador: las circunscripciones territoriales indígenas en la Amazonía Central, 2010-2012

¿Cuáles son los avatares y desencuentros presentes en el proceso de constitución de las Circunscripciones Territoriales Indígenas (CTIs) en relación a la vigencia del derecho a la autodeterminación y autogestión territorial de las nacionalidades indígenas en el Ecuador? Para responder a dicha interrogante, el artículo considera el reconocimiento al derecho a la autonomía y autodeterminación de las nacionalidades y pueblos indígenas en Ecuador. Posteriormente, analiza el alcance de los procedimientos establecidos tanto en la Constitución Política como en el Código Orgánico de Ordenamiento Territorial y Descentralización (COOTAD), y su alcance potencial en generar un nuevo tipo de institucionalidad y una nueva organización territorial en el marco de la definición del Estado plurinacional Ecuatoriano. Esta contribución analiza además el proceso derivado de una hoja de ruta acordada entre el Estado y las nacionalidades amazónicas en el periodo comprendido entre 2010 y 2012, y analiza las diferentes acciones desplegadas desde entonces, enfatizando en los avances y contradicciones, tanto a lo interno del movimiento indígena como en su relación con otras instancias estatales centrales y locales. Se examinan los desencuentros y tensiones a lo interno del aparato Estatal y los sectores mestizos, que no se plantean ningún reparo al momento de obstaculizar los avances del proceso. El artículo analiza el desafío de crear las CTIs en el territorio de los Kichwa de las provincias de Napo y Orellana y en los territorios Kichwa y Achuar en la provincia de Pastaza, en la Amazonía central. Finalmente, el texto puntualiza críticamente algunas de las perspectivas y dilemas que dicho proceso plantea al futuro de la relación Estado-nacionalidades indígenas y al proceso de construcción del Estado plurinacional e intercultural en Ecuador

Socio-Environmental Regimes in Natural Protected Areas: A Case Study in La Sepultura Biosphere Reserve

In this chapter, we analyze the reasons why local socio-environmental systems have met in a limited way the purpose of balancing conservation with development in the Upper Basin of the Tablón River (UBTR), located in La Sepultura Biosphere Reserve (SEBIRE). The study used a transdisciplinary exercise which conceives the Local Socio-Environmental Systems (LSES) as complex and adaptive systems, in which four subsystems interact: (i) the local regime, (ii) the landscape, (iii) the agrarian system, and (iv) the territorial action group. Two common property holdings (“ejidos”) were studied with the case study method. The four subsystems were analyzed through participatory and qualitative research. The results indicated: (a) the local regime imposes norms that limit the decision-making capacity of local actors and its compensatory payments generate dependency and a reactive attitude; (b) the setback of forest frontiers has remained relatively stable due to SEBIRE environmental standards, but natural capital is increasingly vulnerable to socio-environmental disturbances; (c) domestic units (DUs) have little capacity to respond to environmental and market changes; their development is restricted by the geographical, social, and economic conditions of the basin; some producers are unable to cover their production costs and their limited resources barely reach the minimum welfare line; and (d) in the UBTR there are important socio-environmental innovation processes that have generated adaptive management alternatives, but these still face significant challenges at the basin level. In conclusion, the LSES of the UBTR has restrictions on its four components and has not reached the capacity to be socially reproduced. In these LSES, the local regime has promoted an economic model and territorial management mechanisms that have made it environmentally and economically vulnerable

Integración económica de las mujeres rurales. Convenio AECID 07-C01-070 Parte 3

Apoyo a la integración económica de las mujeres en situación de marginación mediante capacitación, generación de ingresos regulares y la inserción en el mercado laboral. Inclusión de las mujeres rurales en los procesos de desarrollo de capacidades económicas, técnico-empresariales y organizativas con incidencia en el cambio de las relaciones de género. Convenio AECID 07-C01-070. Parte 3