Economic evaluation of bio-based supply chains with CO2 capture and utilisation

Carbon capture and storage (CCS) and carbon capture and utilisation (CCU) are acknowledged as important R&D priorities to achieve environmental goals set for next decades. This work studies biomass-based energy supply chains with CO2 capture and utilisation. The problem is formulated as a mixed-integer linear program. This study presents a flexible supply chain superstructure to answer issues on economic and environmental benefits achievable by integrating biomass-coal plants, CO2 capture and utilisation plants; i.e. location of intermediate steps, fraction of CO2 emissions captured per plant, CO2 utilisation plants' size, among others. Moreover, eventual incentives and environmental revenues will be discussed to make an economically feasible project. A large-size case study located in Spain will be presented to highlight the proposed approach. Two key scenarios are envisaged: (i) Biomass, capture or utilisation of CO2 are not contemplated; (ii) Biomass, capture and CO2 utilisation are all considered. Finally, concluding remarks are drawn.Peer ReviewedPostprint (author's final draft

A normal metal tunnel-junction heat diode

We propose a low-temperature thermal rectifier consisting of a chain of three tunnel-coupled normal metal electrodes. We show that a large heat rectification is achievable if the thermal symmetry of the structure is broken and the central island can release energy to the phonon bath. The performance of the device is theoretically analyzed and, under the appropriate conditions, temperature differences up to $\sim$ 200 mK between the forward and reverse thermal bias configurations are obtained below 1 K, corresponding to a rectification ratio $\mathcal{R} \sim$ 2000. The simplicity intrinsic to its design joined with the insensitivity to magnetic fields make our device potentially attractive as a fundamental building block in solid-state thermal nanocircuits and in general-purpose cryogenic electronic applications requiring energy management.Comment: 4.5 pages, 4 color figure

Seeking to enhance the bioenergy of municipal sludge: Effect of alkali pre-treatment and soluble organic matter supplementation

The aim of this research is to enhance the mesophilic anaerobic digestion of municipal sludge from Cadiz-San Fernando (Spain) wastewater treatment plant at 20 days hydraulic retention time (HRT). Two different strategies were tested to improve the process: co-digestion with the addition of soluble organic matter (1% v/v); and alkali sludge pre-treatment (NaOH) prior to co-digestion with glycerine (1% v/v). Methane production (MP) was substantially enhanced (from 0.36 ± 0.09 L CH4 l/d to 0.85 ± 0.16 L CH4 l/d), as was specific methane production (SMP) (from 0.20 ± 0.05 L CH4/g VS to 0.49 ± 0.09 L CH4/g VS) when glycerine was added. The addition of glycerine does not seem to affect sludge stability, the quality of the effluent in terms of pH and organic matter content, i.e. volatile fatty acids (VFA), soluble organic matter and total volatile solid, or process stability (VFA/Alkalinity ratio < 0.4). Alkali pre-treatment prior to co-digestion resulted in a high increase in soluble organic loading rates (more than 20%) and acidification yield (more than 50%). At 20 days HRT, however, it led to overload of the system and total destabilization of the mesophilic anaerobic co-digestion of sewage sludge and glycerine

Mesophilic anaerobic co-digestion of sewage sludge with glycerine: Effect of solids retention time

The main objective of this paper is to examine the effect of the increase in organic loading rates (OLRs), by reducing the solids retention time (SRT) from 20 d to 5 d, in single-phase mesophilic anaerobic co-digestion of sewage sludge with glycerine (1% v/v). It was experimentally confirmed that anaerobic co-digestion of these biowastes under steady-state conditions can achieve an 85 ± 5% reduction in volatile fatty acids (VFA) at SRTs of between 20 and 9 d, with a methane production yield of around 0.8 l CH4/l/d. Decreases in the SRT not only allow the sludge stability and biogas production to be maintained, but also lead to an increase in the waste that could be treated and lower operating costs. Therefore, mesophilic anaerobic co-digestion of sewage sludge and glycerin at a SRT lower than 20 d is possible and preferable due to being more economical and environmentally friendl

Determination of Soluble Sugars in Arabidopsis thaliana Leaves by Anion Exchange Chromatography

Determination of soluble sugars is basic for the study of carbon metabolism in plants. Soluble sugar quantitation can be achieved by enzymatic methods implying different coupled reactions. Here we describe a simple method that allows rapid determination of the most abundant soluble sugars (glucose, fructose and sucrose) in Arabidopsis leaves by anion exchange chromatography. We have applied this method to study the levels of soluble sugars during the photoperiodic transition to flowering (Ortiz-Marchena et al., 2014).España, MINECO projects CSD2007-00057, BIO2008-02292, and BIO2011-28847-C02-00España, Junta de Andalucía P06-CVI-01450 and P08-AGR-0358

Soportes epigráficos de los Orgenomescos

Se presenta un ensayo multidisciplinar con el que se pretende arrojar luz sobre la epigrafía cántabra, mediante la recopilación y estudio, en este caso, de las inscripciones del pueblo de los orgenomescos. El principal objetivo de este trabajo es el análisis de los soportes epigráficos utilizados por los indígenas y su evolución durante la dominación romana mediante el análisis de las 16 inscripciones conocidas, halladas en las actuales provincias de Cantabria, Asturias, Palencia y Jaén. Se distingue una sociedad indígena mixta que presenta un mestizaje entre el mundo prerromano y romano con fuertes pervivencias en sus tradiciones, resultado de un proceso de aculturación e integración onomástica y social.This multidisciplinary essay aims to shed light on the Cantabrian epigraphy, by collecting and studying, in this case, the Orgenomesci people. The main goal of this research are the epigraphic supports used by the natives and their evolution during the roman dominion, by the study of the 16 epigraphic steles and inscriptions found in the actual provinces of Cantabria, Asturias, Palencia and Jaén. Hence, we can perceive a mixted native society with miscegenation between the preroman and roman world, alongside the survival of strong traditions, consequence of an acculturization process, onomastic and social integration

Electro-optical Simulation of a-Si Thin-Film-Transistor Liquid Crystal Display Pixels

An analysis of an amorphous silicon (a-Si) thin-film-transistor liquid-crystal display (TFT-LCD) pixel is presented. The electro-optical model combines the electrical properties of the switching element and the optical performance of a twisted nematic (TN) liquid-crystal cell.Publicad

Characterisation of recycled ceramic mortars for use in prefabricated beam-filling pieces in structural floors

This study analyses a procedure to manufacture mortars with different percentages of ceramic waste as partial replacement for aggregates. The study also examines the physical, chemical and mechanical properties of the new mortars, analysing substitution ratios that range from 10% to 50%. Prior to this, all the materials used in the production of the mortar were characterised using X-ray diffraction (XRD) and fluorescence (XRF). The objective was to determine the similarity between different types of ceramic waste, as well as the differences in the minerology and chemical composition with the aggregate. The results of the study show that it is possible to obtain mortars with lower densities compared to the same product with no recycled content. The product’s characteristics make it ideal for the manufacture of prefabricated components for structural floors for rehabilitation works. Finally, the pieces are used in a real rehabilitation case study, highlightining the structural advantages.Caracterización de morteros con cerámica reciclada y su uso en piezas prefabicadas para entrevigado de forjados. Este trabajo analiza morteros con diferentes porcentajes de cerámica reciclada como sustituto parcial de la arena. Además el estudio examina las propiedades físicas, químicas y mecánicas de los nuevos morteros, empleando diferentes porcentajes de sustitución (10% - 50%). Con anterioridad, se caracterizaron todos los materiales empleados en este trabajo mediante difracción y fluorescencia de rayos-X. El objetivo fue determinar las diferencias y similitudes en la composición química y mineralógica de los distintos tipos de residuos cerámicos y del resto de áridos utilizados. Los resultados muestran que es posible obtener morteros con menor densidad frente a las muestras sin contenido reciclado. Sus características los hacen idóneos para la creación de piezas prefabricadas de entrevigado para rehabilitación de forjados. Finalmente. Las piezas se usaron en un caso de estudio real, destacando las ventajas estructurales que conlleva su uso

Impact of Wetting–Drying Cycles on the Mechanical Properties and Microstructure of Wood Waste–Gypsum Composites

Large amounts of wood waste are generated each year in the world. In an attempt to identify a good recovery option for those residues, wood waste from construction and demolition works were used as raw materials in gypsum plasters. However, wood is a biodegradable material which implies that the products or materials that contain it are susceptible to su ering an important deterioration, due to exposure in certain environments. For that reason, the aim of this work was to simulate the e ects that, in the long term, the atmospheric exposure of wood waste–gypsum composites would have. To do that, the plasters were subjected to 5, 10, and 15 wetting–drying cycles in a climatic chamber. In this study, the density, flexural and compressive strength, and ultrasonic velocity of these composites were determined by the influence of the aging process on their mechanical properties. Furthermore, in order to detect changes on their internal structure, scanning electron microscopy tests (SEM) were used. The results showed that they were suitable to be used as indoor coverings of buildings. However, a treatment to reduce the moisture absorption of the wood waste must be studied if mixtures with high percentages of wood shavings (WS20) are used in wet rooms