•Co-pyrolysis of grape seeds and polystyrene was performed in a fixed-bed reactor.•Potential drop-in bio-fuels were successfully obtained.•An aromatic-rich nature in the bio-oil was ...evidenced.•Undesired both fatty acids and phenols were reduced significantly in bio-oil.•Decarbonylation, decarboxylation and H2-transfer reactions promoted deoxygenation.
Co-pyrolysis of grape seeds and polystyrene was conducted in a fixed-bed reactor, followed by an analysis of the organic phase for possible further application as a drop-in fuel. Significant positive synergistic effects were found with the addition of polystyrene (5–40 wt%) to the conventional pyrolysis of grape seeds. There was a considerable improvement in the organic phase yield, in particular, reaching values over 80 wt%, markedly higher than those obtained from conventional pyrolysis (61 wt%). Fuel properties of the bio-oil were also upgraded, with a decrease in oxygen content and an increase in the heating value. An organic bio-oil fraction with pH values ranging from 5.4 to 6.2 was obtained, reducing the issues associated with handling bio-oils obtained from common pyrolysis of lignocellulosic biomass, usually ranging pH between 2 and 3. Finally, an increment in the desired compounds, mainly aromatics, was also attained, while at the same time achieving a low content of undesired compounds, such as phenols. It was demonstrated that polystyrene can act as a H2-donor, favoring oligomerization, cyclation and hydrodeoxygenation reactions into aromatic compounds.
In this paper, thin-struts of β-type titanium alloy (Ti–29Nb–13Ta-4.6Zr, wt%) were successfully fabricated by cold rolling, and their elastic behavior and mechanical properties are discussed for ...different processing conditions. Before cold rolling, the extremely low yield and ultimate tensile strength of the as-cast and solution-treated specimens, result of a notable “double yielding” behavior, make them inadequate to be applied as structural devices. However, after cold rolling plus short time aging, a nonlinear elasticity with a substantial recoverable strain, considered as the intermediate stage between “double yielding” and normal linear elasticity, is obtained and ascribed to a moderate precipitation of nanometer-sized secondary phases. These precipitates strengthen the material by hindering the motion of dislocations while the β-matrix with relatively low content of β-stabilizers can give rise to a low elastic modulus. The ultimate tensile strength, yield strength, Young's modulus and elastic recoverable strain of the cold rolled plus aged specimens were measured as being between 967 and 1192 MPa, 920–1180 MPa, 48–83 GPa and 1.5–2.0%, respectively. As such, the alloy is anticipated to be promising metallic self-expansible stent material by virtue of the unique combination of extraordinarily high elastic strain, high mechanical strength, and excellent biocompatibility 1, 2.
•Ti alloy with mechanical compatibility for stent applications was fabricated.•Composition design and thermo-mechanical treatments were successfully combined.•A homogeneous distribution of α nano-precipitates strengthened the β-matrix.•The low content of β-stabilizers in the β-matrix resulted in a low elastic modulus.•These findings might expand the application range of β-stabilized Ti-alloys.
Synthetic fuel production from renewable energy sources like biomass is gaining importance driven by the ambitious targets for reducing greenhouse gas emissions worldwide. Sorption enhanced ...gasification (SEG) proposes carrying out the gasification of biomass in the presence of a CO2 sorbent, which allows producing a syngas with a suitable composition for a subsequent synthetic fuel production step. This study aims at analysing the effect of different operating parameters (e.g. steam-to-carbon (S/C) ratio, CO2 sorption capacity and sorbent-to-biomass ratio) in the syngas composition and char conversion obtained in a 30 kWth bubbling fluidized bed gasifier, using grape seeds as feedstock. The importance of reducing the formation of higher hydrocarbons through a high steam-to-carbon ratio and using a CO2 sorbent with high sorption capacity is assessed. C3-C4 and unsaturated C2 hydrocarbons contents below 1%vol. (in dry and N2 free basis) can be achieved when working with S/C ratios of 1.5 at gasification temperatures from 700 to 740 °C. Varying the amount of the CO2 separated in the gasifier (by modifying the temperature or the CO2 sorption capacity of the sorbent) the content of H2, CO and CO2 in the syngas produced can be greatly modified, resulting in a module M = (H2-CO2)/(CO + CO2) that ranges from 1.2 to almost 3.
This Scientific Briefing presents results from a nearly 10‐year hydrometric and isotope monitoring network across north‐central Costa Rica, a region known as a headwater‐dependent system. This ...monitoring system has recorded different El Niño and La Niña events and the direct/indirect effects of several hurricane and tropical storm passages. Our results show that El Niño‐Southern Oscillation (ENSO) exerts a significant but predictable impact on rainfall amount anomalies, groundwater level and spring discharge, as evidenced by second‐order water isotope parameters (e.g., line conditioned‐excess or line‐conditioned (LC)‐excess). Sea surface temperature anomaly (El Niño Region 3) is correlated with a reduction in mean annual and cold front rainfall across the headwaters of north‐central Costa Rica. During El Niño conditions, rainfall is substantially reduced (up to 69.2%) during the critical cold fronts period, limiting groundwater recharge and promoting an early onset of minimum baseflow conditions (up to 5 months). In contrast, La Niña is associated with increased rainfall and groundwater recharge (up to 94.7% during active cold front periods). During La Niña, the long‐term mean spring discharge (39 Ls−1) is exceeded 63–80% of the time, whereas, during El Niño, the exceedance time ranges between 26% and 44%. The regional hydroclimatic variability is also imprinted on the hydrogen and oxygen isotopic compositions of meteoric waters. Drier conditions favoured lower LC‐excess in rainfall (−17.3‰) and spring water (−6.5‰), whereas wetter conditions resulted in greater values (rainfall = +17.5‰; spring water = +10.7‰). The lower and higher LC‐excess values in rainfall corresponded to the very strong 2014–2016 El Niño and 2018 La Niña, respectively. During the recent triple‐dip 2021–23 La Niña, LC‐excess exhibited a significant and consistently increasing trend. These findings highlight the importance of combining hydrometric, synoptic and isotopic monitoring as ENSO sentinels to advance our current understanding of ENSO impacts on hydrological systems across the humid Tropics. Such information is critical to constraining the 21st century projections of future water stress across this fragile region.
The upper and middle panels show conceptual diagrams, including moisture transport and rainfall generation processes within the Central America Cordillera during ENSO neutral and warm phases. The lower panels show the annual LC‐excess (‰) variability during El Niño and La Niña years in rainfall and spring water across the headwaters of central Costa Rica (A) and linear regressions between SST annual averaged anomaly values (Region: Niño 3) and annual LC‐excess (‰) in rainfall and spring water (B).
ABSTRACT
Under the practical symbol of “hacking,” computer expertise has been translated into renewed forms of political action in the past two decades. In this article, I examine this phenomenon ...through the study of self‐organized collectives for technoscientific experts who identify as “hackers.” Based on multisited field research in global cities of the Pacific Rim, I describe the formation of a network of community spaces called “hackerspaces” with a focus on their exchange practices and transnational ties. The alternative globalization of hacking through these convivial spaces for socialization and self‐training has created new political locations and horizons, shifting the moral valence of hacking toward more open and collaborative practices. The hackerspace network is one of the key sites for the observation of this transformation for prefiguring new technical and political practices, hence its relevance for anthropological studies of technology and politics in the contemporary moment. computing, expertise, hacking, technopolitics, hackerspaces
RESUMEN
Bajo el símbolo práctico de lo “hacking,” los conocimientos informáticos han sido traducidos a unas formas renovadas de acción política en las dos décadas pasadas. En este artículo, examino este fenómeno a través del estudio de colectividades autoorganizadas de expertos tecnocientíficos quienes se identifican como “hackers.” Basado en investigación de campo multisitio en ciudades globales en la Cuenca del Pacífico, describo la formación de una red de espacios comunitarios llamado “hackerspaces” con un enfoque en sus prácticas de intercambio y lazos transnacionales. La globalización alternativa de lo hacking a través de estos espacios de convivialidad para la socialización y el autoentrenamiento han creado nuevas localizaciones y horizontes políticos, cambiando la valencia moral de lo hacking hacia prácticas más abiertas y colaborativas. La red de hackerspaces es uno de los sitios claves para la observación de esta transformación para prefigurar nuevas prácticas técnicas y políticas, por lo tanto, su relevancia para los estudios antropológicos de tecnología y política en el momento contemporáneo. informática, conocimiento, hacking, tecnopolítica, hackerspaces
RÉSUMÉ
Sous le symbole pratique du « hacking », l'expertise informatique se traduisait par de nouvelles formes d'action politique au cours des deux dernières décennies. Dans cet article, j'examine ce phénomène à travers l’étude de collectifs auto‐organisés pour des experts technoscientifiques qui s'identifient comme des « hackers ». Reposant sur une recherche de terrain multisituée menée dans des villes mondiales de la ceinture du Pacifique, je décris la formation d'un réseau des espaces appelés « hackerspaces » axés sur leurs liens transnationaux et leurs pratiques d’échange. L'altermondialisation du hacking à travers ces espaces conviviaux de socialisation et d'auto‐formation a créé de nouveaux lieux et horizons politiques, déplaçant la valeur morale du hacking vers des pratiques plus ouvertes et collaboratives. Le réseau des hackerspaces est l'un des sites clés pour l'observation de cette transformation et préfiguration de nouvelles pratiques techniques et politiques. De là découle sa pertinence pour les études anthropologiques de la technique et de la politique dans le monde contemporain. informatique, expertise, hacking, technopolitique, hackerspaces
•Catalytic pyrolysis of wood biomass was studied in an auger reactor.•Several low cost materials were tested as catalysts.•Catalyst to biomass ratio resulted critical to increase bio-oil yield.•The ...studied materials reduced viscosity of bio-oil and improved its stability.•Sepiolite and red mud produced a decrease in the acidity of bio-oil.
Production of upgraded bio-oils by catalytic pyrolysis of wood biomass was studied in an auger reactor using low cost materials as catalysts. These materials included several clay minerals (sepiolite, bentonite and attapulgite) and an industrial waste from alumina production, known as red mud. The influence of temperature (400–500°C) and the effect of catalyst to biomass ratio (3:1–1:6, in weight) were also analysed. A temperature of 450°C and the lowest catalyst proportion (1:6, in weight) were selected as the most appropriate to aim the pyrolysis for bio-oil production. Catalyst to biomass ratio resulted critical since an excess on catalyst addition seemed to reduce liquid production while char yield increased. Under the selected conditions, the catalysts tested improved the characteristics of the obtained bio-oil as fuel (viscosity, acidity, oxygen content and calorific value). For every catalyst, the viscosity of the organic liquid fraction decreased (up to 34% in case of bentonite) while lower heating value increased (up to 20% in red mud tests). Concerning acidity, sepiolite and red mud produced a decrease in the total acid number (around 29% and 23%, respectively). The stability of the organic fraction after aging test (equivalent to long time storage) was also improved by each catalyst.
Groundwater plays an important role in the economic development of the Chaco-Pampean Plain (Argentina), where industry, agriculture and cattle farming are the main economic activities. The 66% of the ...country's population lives in this area. The low slopes of this region condition the water movement and the occurrence of physical and chemical processes. The aim of this work is to update the hydrological conceptual model of the Del Azul Creek basin (Buenos Aires Province), a sub-humid and continental plain, using environmental tracers. In total, the study was based on the analysis of 201 samples (stable isotopes) and 184 samples (chemical data) including rainwater, surface water and groundwater. The temporal and spatial variation in the isotopic composition of rainfall and the hydrological physical-processes, evaporation, surface water-groundwater interaction and recharge were studied. Isotopic compositions of rainfall revealed a seasonal variation across the basin. Low δ18O rainfalls occur during the coldest seasons, while high δ18O rainfalls occur during the warmest seasons. The isotopic compositions of rainfall varied only during the cold period in the upper basin. At this time, the lowest δ18O rainfall fell in the upper basin, while in the other areas and during the warmer seasons, no differences were observed. Evaporation was a relevant process in the flatter area of the basin, mainly during the warmest seasons. Samples taken from the wetlands and from the lower section of the Del Azul Creek were strongly evaporated. In the first 30 m depth of the aquifer, groundwater reflected the isotopic composition of rainfall from the warmest seasons, thus revealing seasonal preferential recharge and a good hydraulic connection. This study provides direct evidence showing that both evaporation and the surface water-groundwater interaction are processes that play a key role in the control of the isotopic and chemical composition of water.
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•The water salinization limits its use.•Stable isotopes revealed recharge-biased towards summer and spring seasons.•Hydrochemistry is controlled by evaporation and surface-groundwater interaction.•A novel conceptual hydrogeological model is presented for a large sub-humid plain.
The storage-discharge relationships of 26 watersheds in the inland Pacific Northwest of the United States were analyzed. Four fitting methods were used to obtain the baseflow coefficients: lower ...envelope, organic correlation, and ordinary and inverse least squares. Several climatic and terrain attributes were evaluated as predictors of baseflow coefficients. Watersheds dominated by basalt and flatter landscapes exhibited the smallest recession time scales (
K
) (12.5–20.0 days). Greater
K
values (33.3–66.7 days) were obtained over catchments dominated by metamorphic and sedimentary rocks. Mean basin slope and the aridity index were found to be the best estimators of baseflow coefficients. Baseflow in flat basalt landscapes, located in dry warm climates, decrease rapidly during summer months and are most sensitive to future droughts and warming climates. Groundwater systems feeding streams during the driest months can drop to less than 1 mm of effective storage in these sensitive systems. In contrast, the minimum annual storage in mountainous systems can have greater than 10 mm effective storage. By understanding the main factors controlling baseflow recession characteristics, environmental agencies could prioritize efforts in areas where future droughts and land use changes may affect ecological assemblages and socio-economic activities.
We present CANOES, an algorithm for the detection of rare copy number variants from exome sequencing data. CANOES models read counts using a negative binomial distribution and estimates variance of ...the read counts using a regression-based approach based on selected reference samples in a given dataset. We test CANOES on a family-based exome sequencing dataset, and show that its sensitivity and specificity is comparable to that of XHMM. Moreover, the method is complementary to Gaussian approximation-based methods (e.g. XHMM or CoNIFER). When CANOES is used in combination with these methods, it will be possible to produce high accuracy calls, as demonstrated by a much reduced and more realistic de novo rate in results from trio data.
The inter-mountainous region of central Honduras has been experiencing abrupt urban drinking water shortages during the last decade. Land use fragmentation and rainfall deficits have rapidly reduced ...surface water quality and quantity in this region. Here we present a 3-yr (2018–2020) tracer study within the headwaters of the Choluteca River basin (2949 km2). We sampled rainfall (weekly N = 156; daily N = 270), drilled wells (N = 166; up to ~300 m depth), boreholes (N = 70; ~4–12 m depth), and springs (N = 128) to assess the spatiotemporal connectivity between rainfall and mean groundwater recharge elevations (MREs). Clear W-shaped incursions characterized rainfall isotopic seasonality from the dry to the wet season. Air mass back trajectory analysis revealed three primary moisture sources: 73 % (east, Caribbean Sea), 17 % (southwest, Pacific Ocean), and 10 % (north; Gulf of Mexico). Groundwater sources exhibited a strong meteoric origin with evidence of secondary evaporation evolution, characterized by low d-excess values. MREs for the drilled wells ranged from 821 to 2018 m asl with a mean value of 1570 ± 150 m asl. Seasonal isotopic variability during dry-wet transitions and the influence of rapid infiltration limited the performance of the MRE method in springs and boreholes. MREs coincided primarily with coniferous forests, pasture, and crop areas, within regions of moderate to high transmissivity. These results are intended to guide the mapping and delineation of critical recharge areas in central Honduras to enhance municipal water regulations, effective environmental protection, and long-term conservation practices.
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•HYSPLIT analysis revealed three main moisture sources: 73 % (Caribbean Sea), 17 % (Pacific Ocean), and 10 % (Gulf of Mexico).•Isotope-inferred MREs (821–2018 m asl) coincided with coniferous forests, pasture, and crop areas.•More accurate conservation and regulation plans can be implemented in central Honduras by providing critical recharge areas.
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