Social networks and trade of services: Modelling interregional flows with spatial and network autocorrelation effects

Recent literature on border effect has fostered research on informal barriers to trade and the role played by network dependencies. In relation to social networks, it has been shown that intensity of trade in goods is positively correlated with migration flows between pairs of countries/regions. In this article, we investigate whether such a relation also holds for interregional trade of services. We also consider whether interregional trade flows in services linked with tourism exhibit spatial and/or social network dependence. Conventional empirical gravity models assume the magnitude of bilateral flows between regions is independent of flows to/ from regions located nearby in space, or flows to/from regions related through social/cultural/ethic network connections. With this aim, we provide estimates from a set of gravity models showing evidence of statistically significant spatial and network (demographic) dependence in the bilateral flows of the trade of services considered. The analysis has been applied to the Spanish intra- and interregional monetary flows of services from the accommodation, restaurants and travel agencies for the period 2000 2009, using alternative datasets for the migration stocks and definitions of network effects.This paper has been developed in the context of different research projects: TransporTrade S2007/HUM/497, (www.uam.es/transportrade), funded by the Education Department of the Madrid Regional Govern ment; the Project (ECO2010 21643/ECON) by the Spanish Ministry of Science and Innovation, as well as the DESTINO Project (Ministerio de Fomento). T. de la Mata also acknowledges the fund received from the Universidad Auto´noma de Madrid (Programa FPI UAM). Carlos Llano also thanks the support received by the New York University Economics Department, where part of this work was also accomplished during an academic stay in the Fall semester 201

Gravity model and tourism: an application to the interregional monetary flows of the Spanish Tourist sector

Este trabajo analiza los flujos monetarios domésticos del sector Turismo en España mediante diferentes especificaciones del modelo gravitatorio, aplicados a tres estimaciones alternativas de los flujos monetarios bilaterales. Los modelos han permitido identificar las principales variables que actúan como factores de atracción de los flujos interregionales, obteniendo elasticidades diferentes para la variable distancia a las observadas en los flujos turísticos internacionales o en el comercio interregional español de bienes. También se muestra la gran importancia del comercio intrarregional y el comportamiento singular de los flujos interregionales entre regiones adyacentes.This work analyses the intra and interregional monetary flows generated by the Tourist sector within Spain, by means of different formulations of the gravity model and three alternative estimates of bilateral monetary flows. The models have also identified some important variables driving the interregional monetary flows of the tourist sector, showing different elasticities for the distance variable than the ones observed in other studies of international tourist flows or the Spanish interregional trade flows of goods. We also show the importance of the intrarregional trade and the special behaviour of the interregional flows between adjacent regions

El comercio interprovincial de bienes en España

En España no existe información oficial sobre el comercio interregional de bienes. En el marco del proyecto C-intereg se ha estimado la primera base de datos de comercio con detalle provincial, tomando como punto de partida la información disponible sobre transporte de mercancías junto con información adicional sobre precios específicos por regiones y productos. La metodología también incluye varios ejercicios de depuración y armonización con las cifras oficiales de producción y comercio internacional. En este artículo se ofrece la primera exploración realizada sobre los flujos provinciales para el periodo 1995-2007, incluyendo un análisis descriptivo profundo que permite clasificar a las provincias españolas según su apertura exterior. Posteriormente, se analiza econométricamente la base de datos utilizando diversas especificaciones de la ecuación gravitatoria para datos de panel. Dicho análisis ha permitido detectar los principales flujos interprovinciales, ofreciendo una radiografía hasta ahora inédita acerca del grado de integración comercial a esta escala territoria

Application of multi-criteria decision-making tools for assessing biogas plants: a case study in Reykjavik, Iceland

The European Union is planning a new program to achieve climate neutrality by 2050. In this context, the Icelandic government plans to ban new registrations of fossil fuel cars after 2030 as one of the strategies to make Iceland a carbon-neutral country by 2040. Upgraded biogas can be directly used in vehicles with CNG engines, reducing CO2 emissions by 80%. In this paper, several alternatives of biogas plants, simulated in previous research, were evaluated by considering techno-economic and environmental criteria through the application of multi-criteria decision-making tools. Twelve alternatives were analyzed using the Definite 3.1 software. A weighted summation algorithm, which transforms all criteria into the same scale by multiplying them by weights and then summing them to obtain the results, was used in the analysis. The multi-criteria analysis of the twelve proposed alternatives included eleven criteria (three technical, five economic, and three environmental) whose weights were changed in a total of eleven scenarios. From a global perspective, when all criteria were considered (9.1% weight) the best alternative with a score of 0.58 was the single-stage biogas plant working with municipal solid waste. Sensitivity and uncertainty analyses also demonstrated that the multi-criteria results obtained were robust and reliable.The APC was paid by the COST Action CA17133 Circular City (“Implementing naturebased solutions for creating a resourceful circular city”, http://www.circular-city.eu, duration 22 October 2018–21 October 2022)

Sustainable management strategy for solidification/stabilization of zinc plant residues (ZPR) by fly ash/clay-based geopolymers

ABSTRACT: Solidification/stabilization (S/S) of acid waste using Ordinary Portland Cement (OPC) is widely implemented, but, due to the impact on climate change, alternative methods are being investigated. In this work, first, the feasibility of using coal fly-ash/clay-based geopolymers for the S/S of Zn plant residues (ZPR), Cadmium Sponge (CS), and Anode Mud (AM) is proposed as a treatment prior to disposal in landfills. Different variables, such as the type of processing, molding (as-received waste), and pressing (dried waste), and activators, a commercial and an alternative residual sodium carbonate, have been studied. The technical and environmental assessments of the S/S process by means of compressive strength and the leaching of critical pollutants have been monitored. Immobilization efficiencies of Cd and Zn higher than 99% have been obtained by dosing 50% of the acid waste, 6 M NaOH solution (20 min contact time), cured at 75 °C (48 h) and at room temperature (28 days), achieving in the leachates pH values of 7 to 10 and [Cd] and [Zn] < 1 and 2.5 mg/kg, respectively. However, alkaline activation increases As leaching, mainly associated with the clay. Secondly, removing clay from the geopolymer formulation, the optimization of geopolymer parameters, acid waste/geopolymer ratio, liquid/solid ratio, and NaOH molar concentration enables obtaining a significant reduction in the release of As and Cd, and Zn is kept at acceptable values that meet the non-hazardous waste landfill disposal limits for the S/S of both acid wastes.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund by means of the research project RTI2018-097612-B-C22

Slow pyrolysis of specialty coffee residues towards the circular economy in rural areas

Coffee, as one of the most consumed beverages, generates a wide variety of waste materials that can be used as biofuels and bio-products. Conventional pyrolysis can be used in rural areas, improving the circular bioeconomy of these places. In this work, the characterization and slow pyrolysis of specialty coffee residues, coffee silverskin (CSS), and spent coffee (SC) were conducted at temperatures from 300 to 600 °C. Physico-chemical and thermal analysis were carried out. In addition, the quantification of individual compounds as acetic, formic, and levulinic acids, caffeine, and other minor compounds was performed. The results indicate the differences between both waste materials in the obtained pyrolysis fractions. The biochar fraction for SC is lower at all temperatures and the liquid fraction higher, reaching maximum values of 62 wt.% in the liquid at 600 °C compared to 47% in CSS. The higher yield in the liquid fraction of SC corresponds to the higher contents of hemicellulose and extractives and the lower ash content. The calculated calorific value for the pyrolysis solid fractions reaches 21.93 MJ/kg in CSS and 26.45 MJ/kg in SC. Finally, biorefinery options of major components of the liquid fraction were also presented.This research was funded by EUROPEAN COMMISSION, Marie Sklodowska-Curie Actions—RISE, grant number 101007733 (CELISE project), by Solvay, under projects 3399 and 3824, and the European LignoCOST Action, number CA17128 (https://lignocost.eu/, accessed on 1 February 2023)

Detoxification of a lignocellulosic waste from a pulp mill to enhance its fermentation prospects

Detoxification is required for sugar bioconversion and hydrolyzate valorization within the biorefining concept for biofuel or bio-product production. In this work, the spent sulfite liquor, which is the main residue provided from a pulp mill, has been detoxified. Evaporation, overliming, ionic exchange resins, and adsorption with activated carbon or black carbon were considered to separate the sugars from the inhibitors in the lignocellulosic residue. Effectiveness in terms of total and individual inhibitor removals, sugar losses and sugar-to-inhibitor removal ratio was determined. The best results were found using the cation exchange Dowex 50WX2 resin in series with the anion exchange Amberlite IRA-96 resin, which resulted in sugar losses of 24.2% with inhibitor removal of 71.3% of lignosulfonates, 84.8% of phenolics, 82.2% acetic acid, and 100% of furfurals. Apart from exchange resins, the results of evaporation, overliming, adsorption with activated carbon and adsorption with black carbon led to total inhibitor removals of 8.6%, 44.9%, 33.6% and 47.6%, respectively. Finally, some fermentation scenarios were proposed in order to evaluate the most suitable technique or combination of techniques that should be implemented in every case.Authors acknowledge the financial support of the European Union by the BRIGIT “New tailor-made biopolymers produced from lignocellulosic sugars waste for highly demanding fire-resistant applications” research project under the seventh framework program www.brigit-project.eu

The effect of rotor geometry on particle size characteristics for knife-milled wheat straw

The paper aimed to experimentally identify the effect of rotor blade geometry on particle size characteristics for the knife-milled wheat straw of 12.5 wt % moisture content. Biomass was systematically reduced in size using two-blade rotor geometries (linear and screw), varying the following conditions: rotor speeds of 10.2 - 20.4 m s - 1 and screen sieve sizes of 0.75 - 10 mm. It was identified that rotor blade geometry affected particle size. The higher the rotational rotor speed and the screen sieve size, the higher the difference in particle size characteristics. The original empiric model was derived and calibrated by studying the mutual relationships among process variables. The model allows predicting characteristic particle size D50 for individual rotor blade geometries, knowing rotor speed and screen sieve size. The accuracies of R2=0.94 for linear- and R2=0.92 for screw-blade rotor geometry were reached for particle size estimation using the derived model.This research was supported by the Ministry of Education, Youth and Sports of the Czech Republic under OP RDE grant number CZ.02.1.01/0.0/0.0/16_019/0000753 "Research centre for low-carbon energy technologies

El comercio interprovincial de bienes en España

En España no existe información oficial sobre el comercio interregional de bienes. En el marco del proyecto C-intereg se ha estimado la primera base de datos de comercio con detalle provincial, tomando como punto de partida la información disponible sobre transporte de mercancías junto con información adicional sobre precios específicos por regiones y productos. La metodología también incluye varios ejercicios de depuración y armonización con las cifras oficiales de producción y comercio internacional. En este artículo se ofrece la primera exploración realizada sobre los flujos provinciales para el periodo 1995-2007, incluyendo un análisis descriptivo profundo que permite clasificar a las provincias españolas según su apertura exterior. Posteriormente, se analiza econométricamente la base de datos utilizando diversas especificaciones de la ecuación gravitatoria para datos de panel. Dicho análisis ha permitido detectar los principales flujos interprovinciales, ofreciendo una radiografía hasta ahora inédita acerca del grado de integración comercial a esta escala territorial.interregional trade; transport flows; border effect; Spanish provinces.

Technical and environmental improvement of the bleaching sequence of dissolving pulp for fibre production

Reactivity of dissolving pulp is one of the main parameters to determine its availability to be transformed into viscose. It is related to the use of carbon disulphide (CS2). An industrial sequential totally chlorine free bleaching process is used as case study. It is carried out in two stages: (1) Alkaline extraction (EOP) and (2) peroxide bleaching (PO). In order to assess how to decrease the use of carbon disulphide, several experiments were performed at laboratory scale for the two stages mentioned before by modifying the operating conditions: NaOH and H2O2 dosages, time and temperature. Reactivity using a modified Fock’s method and pentosan content was analysed along with quality pulp parameters: α-cellulose, viscosity and lignin content (kappa number). Results showed that reactivity increases through the bleaching process and varies with the chemical dosage in both stages. Pulp obtained at the best conditions had the following characteristics: reactivity, 95.3%; α-cellulose 91.17%; intrinsic viscosity, 448 mL/g; kappa number, 1.81 and pentosan content 2.86%, and as a result, CS2 usage was reduced by 11.88%. At the best conditions obtained in this work, NaOH dosage in PO stage was reduced to zero and temperature was slightly lower, when compared with industrial operating conditions