High Flux Values Research Articles

Methods for instrumental assessment of methane emission in reservoirs

Reservoirs are a significant source of methane in the atmosphere. Different estimations of the total methane emission from reservoirs vary greatly. In order to more accurately estimation of the methane emission from reservoirs, it is necessary to investigate the spatiotemporal variability of CH4 fluxes. To study this variability, detailed instrumental measurements of methane fluxes over a long period are required. Such measurements have been carried out for 6 years at the Mozhaisk Reservoir. These measurements showed that the determining factor of the spatiotemporal methane fluxes variability is the meteorological situation and the water level regime. These factors form the stratification of the water column. The highest values of methane flux into the atmosphere are observed in the middle part of the reservoir. The temporal variation of the methane flux is characterized by a general pattern for all years when the measurements were carried out. The methane flux increases during the summer period and reaches the highest values before the beginning of the autumn mixing stage. Also, high flux values observed during periods of storm events that cause mixing of the water column.

Preparation of carbon nanotube/tannic acid/polyvinylpyrrolidone membranes with superwettability for highly efficient separation of crude oil-in-water emulsions

Oil spills and oily industrial wastewater contain insoluble toxic organic molecules, which are harmful to the environment and human health. The preparation of separation membranes with favorable superwettability is crucial for oil-contaminated water treatment. In this study, we prepared a membrane from carbon nanotubes (CNTs), tannic acid (TA), and polyvinylpyrrolidone (PVP) via a green method, without using organic solvents. This membrane exhibited superhydrophilicity and underwater superoleophobicity, along with excellent self-cleaning and anti-fouling properties towards highly viscous crude oil. Furthermore, the CNT/TA/PVP membrane exhibited excellent oil/water separation performance, with very high permeation flux values of up to 7570 and 2634 L m−2 h−1 bar−1for surfactant-free and -stabilized oil-in-water emulsions, respectively. Remarkably, we separated a stabilized crude oil-in-water emulsion using the CNT/TA/PVP membrane. Moreover, these CNT/TA/PVP membranes were resilient under oil accumulation at intermittent pressure during oil/water separation, maintaining a high flux. The high performance of this CNT/TA/PVP membrane, and its green, low-energy, cost-effective preparation, indicate considerable potential for practical applications.

Thermal Transport Analysis of Injected Flow through Combined Rib and Metal Foam in Converging Channels with Application in Electronics Hotspot Removal

The development of miniaturized and more powerful electronic devices and microprocessors has resulted in high heat generation and temperature values in these components. That affects the performance, reliability and lifespan of the devices. In addition, more local hot spots are generated in the components that require even more attention to prevent stress failure and fatigue. As such, the employment of advanced electronics cooling systems is very essential to keep the temperature below the safe temperature. In this work, innovative cooling systems are developed and analyzed employing jet impingement technology, high conductive metal foam, rib structured target surfaces, confined non-uniform small-scale channel, and conductive heat spreader plate. The base of the foam-filled cooling channel is subject to a uniform high heat flux value resembling the electronics device to be cooled. For numerical modeling of thermal transport through foam filled region, the local thermal non-equilibrium model in porous media is utilized resulting in two energy equations for solid and fluid phases. For better understanding of flow and thermal characteristics of jet impingement through the combination of metal foam and rib structured surfaces in confined channels, several effective parameters are studied such as slot and circular jet impingements, the shape and orientation of the ribs, impinging jet velocity, applied heat flux and the thickness of conductive heat spreader plate for hotspot removal. The results show that the fully foam filled channel provides a more efficient cooling in comparison with partially foam filled channel. Furthermore, the results indicate the advantage of utilization of ribs at the stagnation region of the impinging jet, for local thermal treatment of hotspots. The perpendicular cuboid ribs placed at the stagnation zone of the coolant jet impingement provide 13% increase in maximum local Nusselt number while the increase in the pressure drop and required pumping power are as small as 4.2%. Doubling the velocity would result in 35.3% increase in the maximum local Nusselt number, 180% increase in the pressure drop and 460.7% increase in the required pumping power. An increase in the thickness of the conductive heat spreader plate increases the base local temperature but improves local temperature uniformity.

Local radon flux maxima in the quaternary sediments of Schleswig\u2013Holstein (Germany)

This paper presents radon flux profiles from four regions in Schleswig–Holstein (Northern Germany). Three of these regions are located over deep-rooted tectonic faults or salt diapirs and one is in an area without any tectonic or halokinetic activity, but with steep topography. Contrary to recently published studies on spatial patterns of soil radon gas concentration we measured flux of radon from soil into the atmosphere. All radon devices of each profile were deployed simultaneously to avoid inconsistencies due to strong diurnal variations of radon exhalation. To compare data from different seasons, values had to be normalized. Observed radon flux patterns are apparently related to the mineralogical composition of the Quaternary strata (particularly to the abundance of reddish granite and porphyry), and its grain size (with a flux maximum in well-sorted sand/silt). Minimum radon flux occurs above non-permeable, clay-rich soil layers. Small amounts of water content in the pore space increase radon flux, whereas excessive water content lessens it. Peak flux values, however, are observed over a deep-rooted fault system on the eastern side of Lake Plön, i.e., at the boundary of the Eastholstein Platform and the Eastholstein Trough. Furthermore, high radon flux values are observed in two regions associated with salt diapirism and near-surface halokinetic faults. These regions show frequent local radon flux maxima, which indicate that the uppermost strata above salt diapirs are very inhomogeneous. Deep-rooted increased permeability (effective radon flux depth) or just the boundaries between permeable and impermeable strata appear to concentrate radon flux. In summary, our radon flux profiles are in accordance with the published evidence of low radon concentrations in the “normal” soils of Schleswig–Holstein. However, very high values of radon flux are likely to occur at distinct locations near salt diapirism at depth, boundaries between permeable and impermeable strata, and finally at the tectonically active flanks of the North German Basin.

Oxidation-Enhanced Evaporation in High-Carbon Ferromanganese

Thermal fume formation is a problem in manganese ferroalloy production and the metal production industry at large. A better understanding of the mechanisms of fume formation and the operational parameters affecting the fume formation rate may help in reducing and managing fuming. This paper aims to investigate the effects of oxygen content and gas flow rate on the fuming rate and fume particulate properties for liquid high-carbon ferromanganese. The fuming rates were attained experimentally by measuring the fume flux with respect to oxygen content and gas velocity above the metal melt. The generated fumes were also characterized in terms of particle size and element distribution between fume and melt. The fuming rates were found to steadily increase with increasing oxygen content and flow rate of the gas up to a point where the curve flattens, following theoretical predictions. However, the highest flux values measured were above the theoretical limitations of the evaporation flux in vacuo given the alloy bulk composition. It is hypothesized that the high rate of fuming is caused by an increased manganese activity at the alloy surface due to local decarburization of the alloy in contact with the oxidizing gas.Graphical

Modeling of liquid lithium flow in porous plasma facing material

Abstract Flowing liquid lithium can, in principle, create a renewable surface interacting with the plasma, providing protection for the underlying solid substrate. Recent experiments [1] showed that liquid lithium supplied through a porous medium can limit the plasma facing surface temperature, even at high heat flux values in excess of 10 MW/m2. The use of new 3D printing techniques allows creation of plasma facing components that supply liquid lithium through capillary channels. Numerical analysis can be used to develop and optimize porous plasma facing component using virtual prototyping. The present contribution introduces a numerical model of liquid metal flow in a porous structure, interacting with the plasma. The model uses computational fluid dynamics (CFD) to model a flow through a complex 3D geometry including magneto-hydrodynamics (MHD) effects. The CFD set-up covers the liquid metal, plasma and solid structures, simultaneously, connected by realistic interfaces. Small scale interface structures are modeled separately to obtain a self-consistent interface functions. Customized version of the general-purpose CFD is used to handle complex 3D geometries, and efficient pre- and post-processing. MHD is introduced using the magnetic vector potential approach, allowing precise fluid–solid interface treatment. Special stabilization procedures were derived and applied to improve convergence of the momentum balance equations with source terms due to Lorentz force and surface tension. Conjugate heat transfer analysis was performed in the plasma, liquid metal and solid components. The customized code was validated using analytical results for high Hartmann number flow. Results of the validation and numerical analysis of liquid lithium plasma facing components using porous walls will be presented.

Development and characterization of nano-emulsions and nano-emulgels for transdermal delivery of statins

ABSTRACT Background Oral administration of statins for the treatment of familial hypercholesterolemia results in poor therapeutic outcomes and patient compliance. An alternative administration route is proposed to circumvent the current limitations. This research is aimed at developing nano-emulsions and nano-emulgels as the ultimate potential delivery systems of statins for administration via the transdermal route. Methods Oil-in-water (o/w) nano-formulations (nano-emulsions and nano-emulgels) containing 2% (w/w) of the selected statin and 8% apricot kernel oil as oil phase were formulated. The nano-formulations were characterized using transmission electron microscopy (TEM), pH, viscosity, droplet size and zeta-potential. Results Nano-emulsions’ and nano-emulgels’ droplet size ranged between 114.23–169.83 nm and 149.83–267.53 nm, respectively. The addition of Carbopol® Ultrez 20 increased the nano-emulsions’ viscosity (3.59–8.38 cP) resulting in the formation of nano-emulgels (viscosity: 1911.00–46,090.00 cP). The entrapment efficiency (90.77–99.55%) confirmed the incorporation of the statins. Membrane release studies indicated that statins were released at higher flux values in nano-emulsions compared to their respective nano-emulgels. Ex vivo (skin diffusion) studies indicated higher median values in the nano-emulgels compared to their nano-emulsion counterparts. Conclusions The results indicate the benefits of nano-emulsions and nano-emulgels as potential alternative delivery systems for the transdermal delivery of statins.

Utilization of Low Wavelength Laser Linking with Electrochemical Etching to Produce Nano-Scale Porous Layer on p-Type Silicon Wafer with High Luminous Flux

The effect of using high-power He-Cd laser irradiation for electrochemical etching on p-type silicon in hydrofluoric (HF) acid solution was investigated. Laser irradiation on the silicon surface combined with electrochemical etching process successfully controlled the formation of porous silicon (PS) in nano-scale structure. On the surface of the laser-irradiated silicon surface, the formation of nano porous silicon (NPS) during electrochemical etching was controlled by the laser wavelength and power. Then, the NPS was analysed along with physicochemical properties using analytical techniques. The luminous flux of the laser power was controlled with the help of the integrating sphere system. We designated this as the bandgap energy absorption (BEA) of electro-thermal reaction. The fabrication of NPS with laser-irradiation/electrochemical etching technology was feasible by controlling laser power (20 mW) up to a high luminescence flux value of 223 lm. NPS was used in the piratical application of microelectronic device.

The state of microcirculation and identification of microcirculatory predictors of chronic pain in younger patients with functional disorders of the masticatory system affected by connective tissue dysplasia

Relevance. Occlusal splints, made for the patients with temporomandibular disorders (TMD), influence proprioceptive sensitivity, sensory characteristics of pain, parameters of microcirculation of the pulp and periodontium of the healthy teeth. Condition of the pulp and periodontium of the healthy teeth should be assessed in patients with TMD associated with connective tissue dysplasia (CTD).Materials and methods. The study examined 36 TMD patients aged 26.3 ± 1.3 лет (М ± m) with CTD (n = 20, main group) and without CTD (n = 16, control group); with natural teeth, without complaints of TMD, masticatory muscles and periodontal condition. Laser doppler flowmetry (LDF) helped to analyze blood flow parameters in the periodontium and pulp of the healthy teeth. Received results were statistically analyzed.Results. Wavelet analysis revealed different microcirculatory flowmotion: high-amplitude irregular type was in patients of the main group, low-amplitude regular type was in controls. In the main group, perfusion is supported by high values of flux and vasomotion, ergotropic sympathetic effects (controlled by catecholamines) prevail, myogenic tone is reduced, elevated microvascular tone reflects possible changes in rheologic blood properties, microcirculatory signs of pain syndrome and relatively elevated ischemic index in pulp microcirculation of healthy teeth.Conclusion. Sensory and regulatory mechanisms, reflected by the condition of periodontium and pulp blood flow, can be regarded as early signs of inflammation and chronic pain in the diagnosis of TMD in patients without complaints.

PROPRANOLOL HYDROCHLORIDE TOPICAL GEL FOR THE TREATMENT OF INFANTILE HEMANGIOMA

Objective: To formulate and evaluate propranolol hydrochloride topical gel for overcoming the limitations and low oral bioavailability associated with conventional therapy.
 Methods: The propranolol hydrochloride topical gels were prepared by the cold mechanical method. The preliminary evaluation and further characterisation studies was conducted to find the optimised formulation. The in vitro release and ex vivo permeation studies were investigated. The histopathological studies and stability studies was also assessed.
 Results: The propranolol hydrochloride topical gel was successfully prepared. The in vitro release of optimized topical propranolol hydrochloride gel formulation (G2) showed the highest cumulative percentage drug release that is, 95.55%±0.15 after 7.5 h. (G2) the formulation showed a higher flux value of 4.61μg/cm2/h. The histopathological study using pig skin revealed that the optimized formulation was found to be safe for topical application.
 Conclusion: The formulated topical gel containing propranolol Hydrochloride seems to be a promising dosage form for enhanced skin delivery of propranolol hydrochloride in treating Infantile Hemangioma.

Preparation of superhydrophobic and superoleophilic cotton-based material for extremely high flux water-in-oil emulsion separation

Highly stable emulsified water-in-oil mixtures from industrial processes have severe impact on the environment. As their abundance is increasing worldwide, the methods to effectively separate these emulsified water–oil mixtures have attracted significant interest in recent years. Herein, a durable superhydrophobic cotton-based material (SCM) using poly(vinyl phenol), 1,3-phenylene bisoxazoline, and raw cotton was developed. The as-prepared SCM possesses superhydrophobicity (water contact angle > 150°) and superoleophilicity (oil contact angle < 5°). The SCM has excellent repellence not only toward pure water, but also hot water and corrosive aqueous liquids. The superwetting composite also exhibits durable superhydrophobicity after long-term immersion in organic solvents. Moreover, after the compression process, the superwetting material exhibits a remarkable oil–water separation performance. Very high permeation flux values of up to 10,400 ± 400 L m−2h−1 and 867,500 ± 30,300 L m−2h−1 bar−1 are observed for the surfactant-stabilized water-in-oil emulsion by employing gravity-driven and external pressure filtration, respectively, with excellent efficiencies (oil purity of ≥ 99.97 wt%). The outstanding separation performance for various oils and organic solvents, stability in harsh chemical and physical environments, robustness, and recyclability of the superhydrophobic composite make SCM an excellent candidate for large scale application.

Bare and limiter DEMO single module segment concept first Wall misalignment study by 3D field line tracing

Within the framework of EUROfusion DEMO First Wall and limiter design activities, the protection of the First Wall against power deposition peaks is being considered. During steady-state operation, the radiative power from the plasma could be considered more uniformly spread on plasma-facing components than the charged particle power deposition. The presence of openings (i.e. gaps between segments and ports) and the introduction of limiters breaks the continuity of the wall and opens the possibility of localized high heat flux values on toroidal-facing gaps due to charged particles striking the wall. The heat flux pattern is likely to be altered by misalignments between components due to manufacturing, assembly or non-uniform/non-symmetrical operational conditions in the segments.In this paper, the 3D field line tracing code SMARDDA is used for studying the impact of misalignment on the heat load distribution for a periodically segmented DEMO First Wall, specifically the Single Module Segment Concept. The present work does not address any study on limiter misalignments, which will be treated separately. The work covers normal operation conditions (ramp-up and steady-state), considering both the cases of bare First Wall (without limiters, as reference) and First Wall protected by limiters. The main aim of the work is understanding how the power deposition on the First Wall (due to charged particles) is affected by the presence of a radial or vertical misalignment between segments and starting a workflow to be applied later to all the possible plasma scenarios and First Wall layout. Heat flux penalty factor maps have been created to identify the worst cases among the ones analyzed. The related heat flux maps are relevant for thermal assessments of a simplified DEMO model to be performed later on, particularly in terms of maximum temperature values for the current DEMO design.

Post-combustion CO2 capture by coupling [emim] cation based ionic liquids with a membrane contactor; Pseudo-steady-state approach

This study demonstrates the coupling of Ionic liquids (ILs) with a membrane contactor for post-combustion CO2 capture at moderate pressures and temperatures. ILs 1-ethyl-3-methylimidazolium methyl sulfate([emim][MeSO4]), 1-ethyl-3-methylimidazolium dicyanamide([emim][DCA]), 1-ethyl-3-methylimidazolium ethyl sulfate([emim][EtSO4]) and 1-ethyl-3-methylimidazolium acetate ([emim][Ac]) were selected due to their high thermal stability, moderate viscosity and surface tension, as well as high CO2 solubility. No wetting conditions were confirmed for the polypropylene membrane by measuring contact angle, liquid entry pressure (LEP) and SEM of fiber surface before and after the operation. ILs were recirculated in the setup until reaching pseudo-steady-state. All four ILs were able to capture a substantial amount of CO2 during the specified operation time. Initially, very high values of CO2 mass transfer flux and experimental overall mass transfer coefficient were obtained which further decreased with operation time and reached a nearly constant value at pseudo-steady-state. Effect of CO2 loading of the ILs and temperature on enhancement factor and first order rate constant were evaluated. The absorption behavior and kinetics were strongly influenced by the CO2 concentration in the ILs, which divides the absorption process in two steps; an initial faster absorption at the gas-liquid interface and later slower absorption in the bulk of the IL. Finally, a pseudo-steady-state modelling approach was implemented and validated.

Deep CO2 emitted at Furnas do Enxofre geothermal area (Terceira Island, Azores archipelago). An approach for determining CO2 sources and total emissions using carbon isotopic data

Quantification of the CO2 released by the volcanoes to the atmosphere is relevant for the evaluation of the balance between deep-derived, biogenic and anthropogenic contributions. The current study estimates the CO2 released from Furnas do Enxofre degassing area (Terceira Island, Azores archipelago) by applying an approach that integrates the flux of CO2 from the soil with the δ13C-CO2 values. A deep-derived CO2 output of 2.54 t d−1 is estimated for an area of ~23,715 m2. High biogenic-derived CO2 flux values (~45 g m−2 d−1) associated with light carbon isotopic content (δ13C = −28‰ ± 1.1‰) are detected and explained by the type of vegetation that characterizes the study site. Carbon isotopic compositions of the CO2 (−6.4‰ ± 1.2‰) measured in olivine-hosted fluid inclusions of the Terceira basalts are presented for the first time and contribute to defining the mantle-CO2 signature. Differences between these values and heavier carbon isotope values from gas in fumaroles at Furnas do Enxofre (−4.66‰ to −4.27‰) are explained by the carbon isotopic fractionation occurring when CO2 reacts to form calcite in the geothermal reservoir at temperatures >180 °C. A clear correlation between the soil temperature and deep CO2 fluxes is observed and the integration of the diffuse degassing information with the composition of the fumarolic emissions allows estimating a thermal energy flux of 1.1 MW.

Hot-pressed PAN/PVDF hybrid electrospun nanofiber membranes for ultrafiltration

The objective of this study was to develop highly efficient and cost-effective ultrafiltration (UF) media/membranes from electrospun nanofibers alone without using expensive/complicated chemical modification methods. The hypothesis was that, during hot-pressing hybrid electrospun nanofiber membranes (ENMs) consisting of a thermoplastic polymer (e.g., PVDF) and a skeleton polymer (e.g., PAN), the PVDF nanofibers could be partially melted/softened even broken, leading to the conglutination/fusion of nanofibers. This would further result in the reduction of membrane porosities and the variation of membrane morphologies/structures; consequently, the membrane equivalent/apparent pore sizes would also be decreased. To test the hypothesis, as-collected PAN/PVDF hybrid ENMs (PPHENMs) were hot-pressed at 180 °C (above the PVDF melting point of ~177 °C) by using different pressures of 2.5, 5, and 10 MPa; for comparison, PPHENMs were also prepared upon being hot-pressed at 60 °C. The PPHENMs180 hot-pressed under 10 MPa had the lowest porosity of ~16.7 vol%, indicating that nanofibers occupied ~5/6 vol in the membrane; and the membrane exhibited high pure water flux value of ~200 L m−2∙h−1 under the applied pressure of 4 bar. Moreover, this membrane could completely reject/remove polystyrene particles with sizes larger than 20 nm from water; and the rejection percentages for bovine serum albumin and bovine γ-globulin molecules reached ~60% and ~75%, respectively. Therefore, hot-pressed hybrid ENMs made of thermoplastic nanofibers and skeleton nanofibers could provide an innovative and facile approach for the development of high-performance UF media/membranes.

Diatom composition and fluxes over the Northwind Ridge, western Arctic Ocean: Impacts of marine surface circulation and sea ice distribution

Over the last decades, the western Arctic Ocean has undergone unprecedented environmental changes. However, long-term in situ observations of marine phytoplankton are still rare and therefore insufficient to fully characterize their evolutionary trends. This study investigated the diatom fluxes and composition in sediment trap material collected from the Northwind Ridge, western Arctic Ocean, from August 2008 to September 2009. Our data showed that Chaetoceros resting spores were the predominant species, accounting for >40% of the diatom composition. The sea ice diatom group, which included Fossula arctica, Fragilariopsis cylindrus and F. oceanica, dominated the rest of the assemblage throughout the observation period. While diatom fluxes in winter were extremely low, higher flux values were found in summer, and summer 2009 flux values were twice as high as those in 2008. The high total mass and diatom fluxes in summer 2009 were attributed to the combined effect of a weakened Beaufort Gyre, a strengthened Pacific water inflow (PWI) and the distribution pattern of the sea ice. The higher levels of coastal diatoms and terrigenous proxies in summer 2009 were consistent with the intensified PWI. Sea ice diatoms and sea ice biomarker IP25 fluxes were both high during the sea ice melting season and were significantly correlated with each other (r2 = 0.64, p < 0.01). Our data also suggest that sea ice diatoms are prone to selective dissolution in the water column and sediments, implying the existence of biases in diatom assemblage data and subsequently in paleoceanographic reconstructions.

Solid Lipid Nanoparticles for Topical Delivery of Acitretin for the Treatment of Psoriasis by Design of Experiment

The main objective for this investigation is to develop and optimize the solid lipid nanoparticles formulation of acitretin for the effective drug delivery. Acitretin loaded SLNs were prepared by hot homogenization followed by the ultrasonication using Taguchi’s orthogonal array with eight parameters that could affect the particle size and entrapment efficiency. Based on the results from the analyses of the responses obtained from Taguchi design, three different independent variables including surfactant concentration (%), lipid to drug ratio (w/w) and sonication time (s) were selected for further investigation using central composite design. The lipid Dynasan-116, surfactant poloxomer-188 and co surfactant egg lecithin resulted in better percent drug loading and evaluated for particle size, zeta potential, drug entrapment efficiency, in vitro drug release and stability. All parameters were found to be in an acceptable range. TEM analysis has demonstrated the presence of individual nanoparticles in spherical shape and the results were compatible with particle size measurements. In vitro drug release of optimized SLN formulation (F2) was found to be 95.63 ± 1.52%, whereas pure drug release was 30.12 after 60 min and the major mechanism of drug release follows first order kinetics release data for optimized formulation (F2) with non-Fickian (anomalous) with a strong correlation coefficient (R2 = 0.94572) of Korsemeyer-Peppas model. The total drug content of acitretin gel formulation was found to 99.86 ± 0.012% and the diameter of gel formulation was 6.9 ± 0.021 cm and that of marketed gel was found to be 5.7 ± 0.06 cm, indicating better spreadability of SLN based gel formulation. The viscosity of gel formulation at 5 rpm was found to be 6.1 x 103 ± 0.4 x 103 cp. The release rate (flux) of acitretin across the membrane and excised skin differs significantly, which indicates about the barrier properties of skin. The flux value for SLN based gel formulation (182.754 ± 3.126 μg cm−2 h−1) was found to be higher than that for marketed gel (122.345 ± 4.786 μg cm−2 h−1). The higher flux and Kp values of SLN based gel suggest that it might be able to enter the skin easily as compared with marketed gel with an advantage of low interfacial tension of the emulsifier film that ensures an excellent contact to the skin. This topically oriented SLN based gel formulation could be useful in providing site-specific dermal treatment of psoriasis

Natural CO2 degassing in the Mount Amiata volcanic–geothermal area

In the Amiata volcanic–geothermal area, natural soil degassing of CO2 is particularly intense and observed over a wide area, including the volcano complex and its surroundings. A survey systematically and directly measured the natural total soil CO2 flux over the whole area, comprising 2482 measurements over an area approximately 225 km2. Sequential Gaussian simulations generated CO2 flux maps for the entire survey area. These data, when combined with evidence from concentrated degassing emissions, provided an estimate of the area's total CO2 flux (biogenic plus deep CO2) as 13,350 t/d. This mapping and estimation greatly improve the knowledge and understanding of natural CO2 degassing to the atmosphere from this well-known volcanic geothermal area. High values of diffuse CO2 soil flux correspond to both high- and low-enthalpy geothermal areas, confirming the value of the CO2 flux survey methodology to individualize and delimitate geothermal fields and geothermal resources.

Directional Extreme Value Models in Wave Energy Applications

A wide range of wave energy applications relies on the accurate estimation of extreme wave conditions, while some of them are frequently affected by directionality. For example, attenuators and terminators are the most common types of wave energy converters whose performance is highly influenced by their orientation with respect to the prevailing wave direction. In this work, four locations in the eastern Mediterranean Sea are selected with relatively high wave energy flux values and extreme wave heights are examined with wave direction as a covariate. The Generalized Pareto distribution is used to model the extreme values of wave height over a pre-defined threshold, with its parameters being expressed as a function of wave direction through Fourier series expansion. In order to be consistent with the analysis obtained from the independent fits for directional sectors, the estimation of parameters is based on a penalized maximum likelihood criterion that ensures a good agreement between the two approaches. The obtained results validate the integration of directionality in extreme value models for the examined locations and design values of significant wave height are provided with respect to direction for the 50- and 100-year return period with bootstrap confidence intervals.

A Methodological Approach to Determine Sound Response Modalities to Coastal Erosion Processes in Mediterranean Andalusia (Spain)

Human occupation along coastal areas has been greatly increasing in recent decades and, in many places, human activities and infrastructures are threatened by erosion processes that can produce relevant economic and human losses. In order to reduce such impacts and design sound management strategies, which can range from the “no action” to the “protection” option, coastal managers need to know the intrinsic coastal sensitivity and the potential vulnerability and value of land uses. In this paper, in a first step, coastal sensitivity was determined by calculating the following: (i) the spatial distribution at the coast of the wave forcing obtained by using the ERA5 wave dataset and defined as the energy associated with the 50-year return period storm. Two storm conditions were considered, that is, one for the eastern and one for the western parts of the Andalusia Mediterranean coast, respectively, characterized by a height of 8.64–7.86 m and 4.85–4.68 m and (ii) the existence of a buffer zone, namely the dry beach width expressed as a multiple of the 20-year predicted shoreline position that was calculated using a dataset of aerial photographs covering a time span from 1956 to 2016. Coastal sensitivity values were divided into five classes with class 1 indicating the lowest sensitivity (i.e., the presence of a wide buffer zone associated with low wave energy flux values) and class 5 the highest sensitivity (i.e., a narrow buffer zone associated with very high wave energy flux values). In a second step, land uses were obtained from the official Land Use Map of the Andalusia Region, based on the results of the “Coordination of Information on the Environment” (CORINE) European Project. Such uses were divided into five classes from class 1 including natural areas (typologies “A” and “B” of the CORINE Project) to class 5 including very capital land uses (typologies “E1” and “E2”). In a third step, information concerning coastal sensitivity and land uses was crossed to determine the best mitigation strategies to cope with erosion processes. The “no action” option was observed at the westernmost area of Cádiz Province and at some areas from the west coast of Almería Province, where both coastal sensitivity and land use classes show low values; the “adaptation” option was recorded along more than one half of the coast studied, essentially at natural areas with high sensitivity and at urbanized areas with low sensitivity; and the “protection” option was observed especially at some areas from the center and eastern part of Málaga Province and at the easternmost areas of Almería Province, where both coastal sensitivity and land use classes presented high values.