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Dimensions and molecular structures play pivotal roles in the principle of heat conduction. The dimensional characteristics of a solution within nanoscale systems depend on the degrees of confinement. However, the influence of such variations on heat transfer remains inadequately understood. Here, we perform quasi-one-dimensional non-equilibrium molecular dynamics simulations to calculate the thermal conductivity of water molecules confined in carbon nanotubes. The structure of water molecules is determined depending on the nanotube radius, forming a single-file, a single-layer, and a double-layer structure, corresponding to an increasing radius order. We reveal that the thermal conductivity of liquid water has a sublinear dependency on nanotube length exclusively when water molecules form a single file. A stronger confinement leads to behavioral and structural characteristics closely resembling a one-dimensional nature. Moreover, single-layer-structured water molecules exhibit enhanced thermal conductivity. We elucidate that this is due to the increase in the local water density and the absence of transitions to another layer, which typically occurs in systems with double-layer water structures within relatively large radius nanotubes. [ABSTRACT FROM AUTHOR]

Romanian water-cure resorts were established in the mid-nineteenth century following the discovery of thermal waters. The Romanian state and prominent politicians sought to create modern spa resorts (like those established a century before in France and Germany) by allocating funds and implementing public policies and laws to develop bathing establishments for more people who suffered from different ailments. The local spa resorts could promote health tourism with active support from the state and public-private partnerships. Therefore, the two water-cure resorts analysed in this article, Băile Herculane and Băile Govora, with different histories and evolutions, designed modern medical treatments and leisure activities in the interwar period, encouraging wealthy people and people of modest income to spend a holiday and ‘take the cure’ (drinking and bathing) at these resorts. [ABSTRACT FROM AUTHOR]

During the twentieth century, Iceland became a leader in geothermal energy use, with hot water and steam providing for the heating of 9 out of 10 houses and almost one-third of the electricity supply. A crucial factor in the expansion of geothermal energy between the 1940s and 1970s were indirect ‘spillovers’ from the oil industry via the applied geosciences. While fundamentally different in end use, geothermal and hydrocarbon industries employ similar geoscientific methods for exploring and extracting fluids and gases. This article traces the spillovers from oil to geothermal by examining Iceland’s Geothermal Division and its founding director, Gunnar Böðvarsson. He saw the oil industry as a model and embraced its geoscientific exploration methods, oilwell rotary drilling and petroleum reservoir engineering. Adapted to the requirements of geothermal energy, petroleum technologies greatly improved the knowledge of geothermal reservoirs and the efficiency of well drilling and hot water and steam extraction. The geoscience spillover between oil and geothermal reveals an understudied dimension of geothermal history and the crucial role of the geosciences at the intersection of academia and energy industries, which also resulted in reverse spillovers from geothermal to oil and complicates the common dichotomization of fossil fuels vs. renewable alternatives. [ABSTRACT FROM AUTHOR]

A 2-fold interpenetrating 3D pillar-layered MOF, which was assembled from a mixed-linker and paddle-wheel cluster, was successfully synthesized. It possesses good thermal and water stability as well as high selectivity for C2H6 over CH4 and CO2 over N2 under ambient conditions, which was further proved by breakthrough experiments. Moreover, this porous material exhibits good detection of Cu2+, [Co(NH3)6]3+ and Fe3+ in an aqueous solution. [ABSTRACT FROM AUTHOR]

Seismic events triggered by stress unloading during geo-energy extraction activities have become a key focus in both seismological research and engineering safety. This study presents a novel application of waveform neural networks, combining unsupervised and supervised learning techniques to classify and characterize fractures in laboratory-induced seismic events. Initially, A neural network model was initially developed that is capable of extracting time-frequency features from waveforms through unsupervised training on 1.2 million Acoustic Emission waveforms. Subsequently, this model was fine-tuned using a labeled dataset obtained from Brazilian split and uniaxial compression tests. The final result was a highly accurate model, achieving an accuracy rate of 97.6%. By applying this refined model, insights have been gained into the complex fault slip behaviors induced by geo-energy extraction activities. Our findings reveal that fluid infiltration at the onset triggers low-energy, shear-induced fractures in low-stress fault regions, which then escalate into tensile fractures during critical sliding in high-stress areas. Key precursors to fluidinduced seismicity have been identified, providing a major advance in early seismic hazard detection. These insights are essential for monitoring and early warning of induced seismicity during geo-energy extraction activities. Our work contributes significantly to improving the safety and efficiency of geo-energy extraction, including geothermal, shale gas, and conventional hydrocarbon production. [ABSTRACT FROM AUTHOR]

Enhanced geothermal systems in hot dry rocks are among the most promising sources of green renewable energy, with increasing interest in Central and Eastern Europe. The effective implementation of enhanced geothermal systems in new areas is based on the use of insights from ongoing projects, particularly in the study of petrophysical properties and reservoir stimulation technologies. This study aimed to characterize hot dry rocks in Central Europe by analyzing permeability, porosity, mineral composition, elastic properties, and brittleness index to assess their susceptibility to hydraulic fracturing. Drill core samples were collected from three formations: granites from the Karkonosze Mountains, volcanic rocks from the Gorzów Block, and tight sandstones from the Mogilno-Łód´z Trough. The results indicated that the petrophysical properties and mineral compositions of these rocks are comparable to the corresponding Western European formations. Altered granites and some volcanic rocks showed significant decreases in wave velocities compared to intact samples, while sedimentary formation exhibited lower elastic moduli, indicating less favorable conditions for the development of the fracture network. Dynamic elastic tests suggested that brittleness index interpretation should differ between sedimentary and igneous hot dry rocks. In sedimentary formations, high brittleness index values indicate zones with elevated potential for complex fracture networks, aligning with the classic brittleness index concept. On the contrary, in igneous formations, low brittleness index values indicate zones of alteration and well-developed natural fractures, which are beneficial for hydroshearing stimulation. [ABSTRACT FROM AUTHOR]

Investigating the coupling effects of temperature levels and heating-water cooling cycles on the physical and mechanical responses of HDR (hot dry rock) is a vital issue during the exploitation of geothermal energy. In this study, the physical properties of granite specimens were measured first after each heating and water-cooling cycle. Then, uniaxial compressive tests were conducted on those granites to obtain their mechanical properties. With the increase in heating temperature (T) and cycles of heating and water cooling (N), P-wave velocity, uniaxial compression strength (UCS), and elastic modulus (E) showed a decreasing tendency, and the decrease of those four properties corresponding to T variation is greater than N variation. Due to the α-β phase transition of quartz happening at 573°C, the density UCS and E of granite decreased rapidly when the heating temperature increased from 450°C to 600°C at N = 1. With the increase of T and N, the failure mode of granite gradually changes from tensile failure to shear failure and, finally, comminute failure. The failure mechanism of granite gradually transfers from brittleness-dominated to ductility-dominated due to accumulated thermal damage. Finally, X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to determine the damage mechanism of cyclic heating-cooling. The micro test results show that the high-temperature treatment changes the mineral composition and the microcracks number of the granite and finally affects the macroscopic physical and mechanical properties. The study conclusions of this manuscript are important for exploiting geothermal resources. [ABSTRACT FROM AUTHOR]

Rare metals such as lithium (Li), rubidium (Rb), and cesium (Cs) are strategically crucial mineral resources for the development of emerging industries in China. Ensuring a stable long-term supply of these resources is essential. The geothermal systems in Xizang, China are well-developed, with a wide distribution of various types. Most high-temperature geothermal systems in Xizang are exceptionally enriched in rare metal elements (RMEs) and have the potential to become a new source of rare metals to secure China's strategic mineral resource supply in the future. A close relationship also exists between the geothermal system and the special salt lake resources on the Tibetan Plateau. Geothermal springs thus play a key role in the migration and enrichment of RMEs from deep to shallow parts of the crust, in the transition between endogenous and exogenous mineralization, and source-to-sink processes. However, the mechanisms of element enrichment and evolution in these springs have not been systematically discussed, and many theoretical issues remain to be investigated. Based on summarizing and analyzing previous research, this study employs hydrochemical and isotopic geochemistry methods to investigate typical geothermal springs across Xizang and explore the anomalous enrichment mechanism of RMEs, and the resource effects of geothermal springs. Comprehensive analysis shows that the total dissolved solids (TDS) and hydrochemical types of geothermal springs are similar to those of major geothermal fields worldwide, but the Tibetan springs are abnormally rich in Li (averaging 5.48 mg/L), Rb (averaging 0.75 mg/L), and Cs (averaging 3.58 mg/L), which are hundreds to thousands of times more concentrated than natural waters. The distribution of these enriched geothermal springs is controlled by the Yarlung Zangbo suture zone and the extended N-S trending rifts, especially in the intersection zone of the two, where the geothermal springs are the most enriched. Based on the spatial distribution, isotopic, and elemental geochemistry, the RMEs enriched in Tibetan geothermal springs are mainly derived from the magmatic-hydrothermal fluids generated by the partial melting of the subducted Indian plate under the Eurasian continent. These fluids not only maintain geothermal activities as a heat source but also participate in the material cycle of the geothermal spring as a material source. Against the background of regional crustal enrichment in RMEs, incompatible elements such as Li, Rb, and Cs are gradually enriched in magmatic-hydrothermal processes including partial melting in the source, magmatic differentiation, and hydrothermal fluid exsolution, and some ore-forming elements are further extracted from surrounding rocks through deep high-temperature water-rock interactions. Eventually, an eruption occurs, and these fluids move to the surface to form a geothermal spring rich in RMEs. With the drainage of geothermal springs, the RMEs are continuously transported to the lake basin by surface runoff and continue to concentrate and evolve into salt lake brines under an extremely arid climate environment, constituting an endogenous source and exogenous accumulation salt lake metallogenic model. This comprehensive explanation of the sources, migration, enrichment mechanisms, and resource effects of geothermal springs will deepen the understanding of rare metal mineralization processes, and aid in the advancement of theoretical models for key rare metal mineral resources in various geological bodies of the Tibetan Plateau, significantly expanding exploration scopes and accurately assessing the resource potential of RMEs. [ABSTRACT FROM AUTHOR]

Some residents of Mount Amiata in Tuscany, Italy, are experiencing emotional distress and solastalgia due to changes in their beloved land. Mount Amiata is witnessing protests by citizens' associations and activists who criticize the alleged social, economic, and environmental sustainability of geothermal energy. The analysis of the environmental conflict around geothermal energy on Mount Amiata contributes to the empirical use of the concept of "solastalgia" as affective rupture of biocultural relationships and identities. In the area surrounding Mount Amiata, the production of geothermal energy is experienced as an attack on the biodiversity of the "Mother Mountain," as a loss of the sense of home, and as part of a "predatory philosophy" employed by ENEL (Ente Nazionale per l'Energia Elettrica, National Electricity Board). This ethnographic study aims to analyze how the transformation of places influences the affective and biocultural identity of their inhabitants. [ABSTRACT FROM AUTHOR]

The Permian (Changhsingian) Umm Irna Formation (Jordan) yields important plant fossils that have influenced our understanding of the early evolution of plants that later dominated the vegetation of the Mesozoic. The formation was deposited in a fluvial regime characterised by the co-occurrence of stacked small-scale braided channels and of larger, higher-sinuosity channels with deposition on point bars, all intercalated into a heterogeneous background sedimentation of finer-grained floodplain deposits, including stacked crevasse-splay deposits, interspersed abandoned-channel and oxbow-lake fills, and lenses of peaty back-swamp deposits. Here, we document the remarkable compositional variability expressed in 124 palynomorph assemblages that were recovered from different argillaceous deposits in the Umm Irna Formation within a ∼2 km2 outcrop area around a major meandering channel. Our results reveal lateral and vertical variation within individual argillaceous units, as well as lateral variation between different argillaceous units in the same sedimentary complex at similar stratigraphic levels. When combined with plant macrofossil data, the results show that variability in the palynological content may be influenced mainly by two factors. The first is connectedness to the major channel; the drainage system carried a mixture of palynomorphs from across the floodplain but also from a large hinterland of tributaries draining higher parts of the floodplain and uplands beyond to the south and east. The second is the influence of local vegetation communities on the floodplain which would likely be more marked in less connected parts of the floodplain. These findings have implications for the palynological study of alluvial sequences of the Palaeozoic and Mesozoic, and for understanding the ability to identify mudstone units via palynological fingerprinting. Such individual units are of great importance as baffles to fluid flow in reservoirs that might be used for oil and gas, low-temperature geothermal energy storage, carbon capture and storage, and hydrogen storage in alluvial successions. [ABSTRACT FROM AUTHOR]

Terrestrial heat flow plays a vital role in determining the present thermal regimes of sedimentary basins, offering a robust foundation for understanding hydrocarbon maturation processes and the geothermal resource potential. The Junggar basin is one of the largest and most petroliferous superimposed petroleum basins in China. However, research on heat flow is scarce. In this study, 94 new high-quality heat flow values are derived from through borehole temperature analysis and thermal conductivity measurements of rocks. The results indicate that (1) the geothermal gradient in the basin varies from 11.4 to 28.3 °C km−1, with a mean value of 20.9 ± 3.4 °C km−1, and the heat flow varies from 23.4 to 64.5 mW m−2, with a mean value of 45.1 ± 8.4 mW m−2. The overall low geothermal gradient and heat flow are attributed to the continuous cooling during the Meso-Cenozoic. (2) At basin scale, the high heat flow values are primarily concentrated in areas characterized by basement uplift, whereas the low heat flow values are mainly located in the depressions. This suggests that thermal refraction is the primary factor influencing the heat flow variations. (3) Although large-scale development and utilization of geothermal resources face challenges, certain local areas in the basin show promise for geothermal resource utilization. [ABSTRACT FROM AUTHOR]

Summary: To meet the demand for gluten‐free (GF) products, this study developed artisanal fresh pasta using teff, rice, and buckwheat flours, enhanced with mineral‐rich thermal waters (TW). A mixture design approach optimised flour proportions to balance texture, cooking time, water absorption, and cooking loss, along with functional properties such as total phenolic compounds (TPC) and antioxidant activity. Two promising formulations were identified: 36.3 g buckwheat, 9.35 g rice, and 9.35 g teff; and 27.5 g teff and 27.5 g buckwheat. These formulations, with and without TW, were evaluated for chemical, technological, microbiological, and functional attributes. The pasta had satisfactory technological properties, macronutrient levels comparable to standard pasta, and was rich in phenolic compounds with antioxidant activity. Ca, Zn, Fe, K, and Mn were predominant, although TW incorporation did not significantly affect their levels in the samples. All formulations showed microbiological stability for at least 3 days at 4 °C. [ABSTRACT FROM AUTHOR]

Crystalline rocks in the subsurface are of interest for geothermal energy extraction, nuclear waste storage, and, when weathered or fractured, as aquifers. Compliant discontinuities such as microcracks, cracks and fractures may nucleate and propagate due to changes in pore pressure, stress and temperature. These discontinuities may provide flow pathways for fluids and, if fracturing extends to surrounding rocks, may allow escape of fluids to neighbouring formations. Monitoring such rocks using sonic logs, passive seismic, borehole seismic and surface seismic requires understanding of the propagation of elastic waves in the presence of such discontinuities. These may have an anisotropic orientation distribution as in situ stress may be anisotropic. As crystalline rock may display intrinsic anisotropy due to foliation and the preferential orientation of anisotropic minerals, quantification of the relative importance of intrinsic and microcrack‐induced anisotropy is important. This may be achieved based on the stress sensitivity of elastic wave velocities. A method that allows both the orientation distribution of microcracks and the stress dependence of their normal and shear compliance to be estimated independently of the elastic anisotropy of the background rock is presented. Results are given for anisotropic samples of gneiss from Bukov in the Czech Republic and granite from Grimsel in Switzerland based on the ultrasonic velocity measurements of Aminzadeh et al. The microcrack orientation distribution is approximately transversely isotropic for both samples with a preferred orientation of microcrack normals perpendicular to foliation. This preferred alignment is stronger in the sample of gneiss than in the granite sample, and the normal and shear compliance of the microcracks decreases with increasing compressive stress. This occurs because the contact between opposing faces of the discontinuities grows with increasing compressive stress, and this results in a decrease in elastic anisotropy with increasing compressive stress. At low stress, the ratio of microcrack normal compliance to shear compliance is approximately 0.25 for the granite sample and 0.7 for the sample of gneiss. The normal compliance ZN for both samples decreases faster with increasing compressive stress than the shear compliance ZT, resulting in a decrease in ZN/ZT with increasing compressive stress. [ABSTRACT FROM AUTHOR]

In this study, geothermal energy has demonstrated significant potential as a sustainable and renewable energy resource for space conditioning. However, developing nations like India have not yet adopted this technology for space heating and cooling, despite experiencing satisfactory seasonal variation in ambient temperatures in many places. Furthermore, the thermo-mechanical behavior of geothermal energy piles in the specific soil and climatic conditions of the area has not been investigated. The present study aims to numerically explore the thermo-mechanical response of a geothermal energy pile in the local soil under the climatic conditions of Jamshedpur, a city in Eastern India. The study analyzed the shear stress at the interface of the pile and adjacent soil, the displacement of the pile head, middle, and toe, and the volumetric strain of the soil. The results of this study was validated and compared with previous studies and found a good agreement with it. The maximum displacement for mechanical loading was observed to be 16 mm in sand and 11.4 mm in layered soil, respectively, for an L/d ratio of 15. Under thermo-mechanical loading, the change in displacement was 0.7 mm in sand and 0.4 mm in layered soil. The maximum shear stress was developed at the toe, reaching 60 kN/m2 for L/d = 15. The obtained results reveal an encouraging outcome and help in gaining confidence in constructing geothermal energy piles. [ABSTRACT FROM AUTHOR]

The combination of renewable energy and liquefied natural gas (LNG) cold energy can effectively improve energy utilization efficiency and achieve the goal of energy conservation and emission reduction, which is one of the important directions of future development. This work proposed a cascade organic Rankine cycle (ORC) driven by a geothermal heat source and an LNG heat sink. Seven organic fluids are chosen as candidates to form different working fluid pairs. The effects of the main design parameters on system performance are carried out through the thermodynamic analysis. Then, the optimal design conditions and fluid selection schemes are searched based on the single-objective optimization results. Finally, the exergy destruction study is conducted under the optimal design conditions and working fluid pair. Results showed that the cascade ORC system using the working fluid pair of R601/R290 had the highest exergy efficiency, which could reach 20.02%. At the same time, under the optimal design conditions, the secondary cycle condenser and LNG direct expansion brought high exergy destruction, which was respectively 29.3% and 25.8%, and followed by the two turbines in the cascade ORC system, which were 16.1%, 11.2% and 7.7%. [ABSTRACT FROM AUTHOR]

This paper investigates the feasibility of coaxial deep borehole heat exchanger (CDBHE) applications to the University of California San Diego (UCSD) campus. By collecting different geophysical source data for various formations and well logs around the UCSD campus, a multilayered thermophysical model for the ground on the site is established. Water circulation within a closed coaxial loop system considers the geothermal energy extraction under uncertainty consideration of the unknown deeper layers heat flow gradient as coupled with the variation of pipe insulation properties, flow rates, outer pipe diameter, grout, and depths between 1 and 4 km. A finite-element framework models the Navier–Stokes fluid flow and heat transfer in the CDBHE system, validated with a field test on CDBHE from the literature. Results show that a 4-km CDBHE could produce a thermal power of 600 kW under the optimum geological conditions at the UCSD site: the water flow rate of 2.78 L/s and a ground thermal gradient of 60 ℃/km. Thermal power shares from different layers indicate that deeper formation layers contribute more to the thermal power than the shallower layers because increasing the CDBHE length from 1 to 4 km can lead to a maximum of 900% increase in thermal power and a 50% expansion in thermal plume for a CDBHE with an insulated inner pipe between the upper and lower bound heat flow bounds. An inner pipe with an insulated depth of 2 km produces only 1–6% less power than a fully insulated inner pipe for the 4-km CDBHE, and thus, a partially insulated vacuum-insulated tube (VIT)-plastic inner pipe is suggested as the best practice. Furthermore, the CDBHE thermal power increases by 5% when the grout thermal conductivity increases from 1 to 3.65 W/(K∙m), close to the formation thermal conductivity, and then maintains almost the same, and the 4-km CDBHE with flow rates of 2.78–6.94 L/s at the UCSD site can directly supply a low-temperature heating radiator system for room heating. This study suggests practical ranges for geothermal energy extraction for southern California. A CDBHE with a well-insulated inner pipe of 0.05 W/(m∙K), the thermal power of lower and upper-bound heat flow cases can vary by 60% from the mean. Finally, water as the working fluid is more efficient than CO2, doubling CDBHE's thermal power. The effects of the investigated factors provide guidelines for future geothermal resource exploitation in southern California. [ABSTRACT FROM AUTHOR]

Translation abstract Energy‐activated steel solutions for climate‐positive buildingsThe overall research project “Energy‐activated steel solutions for climate‐positive buildings” is developing, investigating and evaluating new solutions with a highly innovative character and considerable potential in terms of the energy transition. The aim is the further dissemination and application of steel as a material in the building sector as a contribution to the energy and heat transition and to increasing sustainability in the construction industry. In order to structure the extensive objectives of the project, the overall project was divided into four sub‐projects. In the first three sub‐projects, different topics are addressed that fall under the main theme of “Energy‐activated steel solutions for climate‐positive buildings”. These topics will be investigated, optimized and evaluated using real demonstrators. In the fourth sub‐project, the individual solutions developed for energy generation from the ground and the environment, optimization of the building envelope, technical solutions for energy storage and energy transfer to the room are brought together in a virtual building demonstrator. In this virtual environment, the components for energy generation (geothermal energy, solar thermal energy, photovoltaics) can be tested and evaluated in combination with the energy conversion and transfer components. At the end of the project, the aim is to show how the goal of a climate‐positive building can be achieved through the systematic use of steel solutions. [ABSTRACT FROM AUTHOR]

This study investigates the effect of thermal treatment on the composition and morphology of cobalt oxide nanofibers synthesized via electrospinning. Cobalt acetate tetrahydrate and poly (vinyl alcohol) were used as precursors to produce cobalt acetate/poly(vinyl alcohol) nanofiber mats. The electrospun mats were subjected to various thermal treatments, including calcination in air at 500∘C, calcination under argon at 700∘C and 850∘C and treatment with water gas (CO and H2) at 180∘C. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction were employed to characterize the nanofibers. The results demonstrated that the polycondensation tendency of cobalt acetate and the supportive properties of poly(vinyl alcohol) led to the maintenance of nanofibrous morphology across all thermal treatments. Calcination in air produced dense, highly crystalline Co3O4 nanofibers. In contrast, calcination under argon at 700∘C resulted in an amorphous carbon matrix embedded with small cobalt-based nanoparticles, while at 850∘C, the nanofibers contained larger, highly crystalline cobalt nanoparticles. Thermal treatment with water gas transformed the nanofibers into nano-belts primarily composed of crystalline CoO and Co3O4, with minimal amorphous phase. This study highlights the critical influence of thermal treatment on the structural and compositional properties of cobalt-based nanofibers, offering insights for tailoring these materials for applications in catalysis, energy storage and electronic devices. The findings emphasize the potential of controlled thermal strategies to produce diverse cobalt-based nanostructures with distinct properties. [ABSTRACT FROM AUTHOR]

Reducing the fire risk of epoxy coatings has been a significant focus in the research of thermosetting resin materials. Various carbon nitride/polyaniline/metal oxide hybrids (CNPMOs) were synthesized using in‐situ oxidative polymerization and modified adsorption methods. Combustion analysis results indicated that CNPMOs effectively reduced the heat release of epoxy coatings during combustion. The epoxy coatings containing various CNPMOs (EFe, EY, and ETi) exhibited excellent smoke suppression and toxicity reduction properties. Furthermore, in comparison to the pure sample (E0) and reference sample (E1), the epoxy coatings EFe, EY, and ETi demonstrated improved thermal stability. In water resistance tests, the water absorption rates of EFe, EY, and ETi were significantly lower than that of E0. The CNPMOs enhanced the hydrophobicity of the epoxy coating to better protect the substrate in humid environments. [ABSTRACT FROM AUTHOR]

Given the distinct water management requirements in anion-exchange membrane fuel cells (AEMFCs) and proton-exchange membrane fuel cells (PEMFCs), the necessity for tailored flow field redesign and analysis in AEMFCs becomes paramount. In this study, a three-dimensional, two-phase, non-isothermal AEMFC model is constructed to explore the impact of the channel shape of a parallel flow field on the cell performance. The results demonstrate that the channel shape notably influences cell performance at low voltages, and the cell performance follows: inverted trapezoidal > square > triangular > rectangular > trapezoidal > semicircular. A cell with inverted trapezoidal channels achieves a 12.9% increase in peak power density and an 83.4% reduction in current density non-uniformity compared to that with semicircular channels. Analysis of the evaluation criteria indicates that excellent heat transfer performance, superior mass transfer performance, and sufficient water content in the membrane are critical for improving AEMFC performance. • Effect of six channel geometries on the AEMFC performance is investigated. • EMTC, EEC, and inhomogeneity index are used to evaluate the whole performance. • Inverted trapezoidal channels yield the best overall performance. • Triangular channels result in the lowest EEC. [ABSTRACT FROM AUTHOR]

This study reports on newly acquired density data of synthetically prepared pure and mixed NaCl and CaCl2 aqueous solutions that span a wide range of geothermally encountered concentrations and mixing ratios. The analytical data are provided for the temperature range of 293–353 K at ambient pressure. For the reproduction of that data, PHREESCALE was used. The predictive potential of this numerical tool regarding the density of geothermal fluids of known composition was the major target herein. As a result, the measured data are in good agreement with previous analytical studies found in the literature. Possible sources of errors are discussed in this paper. Density data of the mixed solutions at temperatures other than ambient are unique and close existing data gaps. The numerical model reproduces the newly measured and already existing density data within an error band of approximately 1%. For further use in geothermal applications, this can be considered an excellent agreement. Moreover, the model yields a direct calculation of density without the need to establish complex empirical equations of state and mixing rules. Finally, sensitivity calculations performed with a thermal–hydraulic (TH) numerical reservoir model demonstrate the required accuracy of fluid density for reliably predicting the long-term performance of deep geothermal energy systems. In terms of the productivity index and the timing of thermal breakthrough it shows that the present analytical and numerical uncertainty in density is small enough to reliably state both reservoir parameters. [ABSTRACT FROM AUTHOR]

Due to its simple structure and stable operation, the Organic Rankine Cycle (ORC) has gained significant attention as a primary solution for low-grade thermal power generation. However, the economic challenges associated with development difficulties in hot dry rock (HDR) geothermal power systems have necessitated a better balance between performance and cost effectiveness within ORC systems. This paper establishes a game pattern of the Organic Rankine Cycle with performance as the master layer and economy as the slave layer, based on the Stackelberg game theory. The optimal working fluid for the ORC is identified as R600. At the R600 mass flow rate of 50 kg/s, the net system cycle work is 4186 kW, the generation efficiency is 14.52%, and the levelized cost of energy is 0.0176 USD/kWh. The research establishes an optimization method for the Organic Rankine Cycle based on the Stackelberg game framework, where the network of the system is the primary optimization objective, and the heat transfer areas of the evaporator and condenser serve as the secondary optimization objective. An iterative solving method is utilized to achieve equilibrium between the performance and economy of the ORC system. The proposed method is validated through a case study utilizing hot dry rock data from Qinghai Gonghe, allowing for a thorough analysis of the working fluid and system parameters. The findings indicate that the proposed approach effectively balances ORC performance with economic considerations, thereby enhancing the overall revenue of the HDR power system. [ABSTRACT FROM AUTHOR]

The Organic Rankine Cycle (ORC) is a widely utilized technology for generating electricity from various sources, including geothermal energy, waste heat, biomass, and solar energy. Harnessing solar radiation to drive ORC is a promising renewable energy technology due to the high compatibility of solar collector operating temperatures with the thermal requirements of the cycle. The aim of this review article is to present and discuss the principles of solar-ORC technology and the broad range of solar-ORC systems that have been explored in the literature. Various solar energy technologies capable of powering ORC are investigated, including flat plate collectors, vacuum tube collectors, compound parabolic collectors, and parabolic trough collectors. The review places significant emphasis on the operating parameters of technology. [ABSTRACT FROM AUTHOR]

This paper presents an analysis and optimization of a polygeneration power-production system that integrates a concentrating solar tower, a supercritical CO2 Brayton cycle, a double-flash geothermal Rankine cycle, and an internal combustion engine. The concentrating solar tower is analyzed under the weather conditions of the Mexicali Valley, Mexico, optimizing the incident radiation on the receiver and its size, the tower height, and the number of heliostats and their distribution. The integrated polygeneration system is studied by first and second law analyses, and its optimization is also developed. Results show that the optimal parameters for the solar field are a solar flux of 549.2 kW/m2, a height tower of 73.71 m, an external receiver of 1.86 m height with a 6.91 m diameter, and a total of 1116 heliostats of 6 m × 6 m. For the integrated polygeneration system, the optimal values of the variables considered are 1437 kPa and 351.2 kPa for the separation pressures of both flash chambers, 753 °C for the gasification temperature, 741.1 °C for the inlet temperature to the turbine, 2.5 and 1.503 for the turbine pressure ratios, 0.5964 for the air–biomass equivalence ratio, and 0.5881 for the CO2 mass flow splitting fraction. Finally, for the optimal system, the thermal efficiency is 38.8%, and the exergetic efficiency is 30.9%. [ABSTRACT FROM AUTHOR]

The Cerro Prieto basin, a tectonically active pull-apart basin, hosts significant geothermal resources currently being exploited in the Cerro Prieto Geothermal Field (CPGF). Consequently, natural tectonic processes and anthropogenic activities contribute to three-dimensional surface displacements in this pull-apart basin. Here, we obtained the Cerro Prieto Step-Over 3D surface velocity field (3DSVF) by accomplishing a weighted least square algorithm inversion from geometrically quasi-orthogonal airborne UAVSAR and RADARSAT-2, Sentinel 1A satellite Synthetic Aperture-Radar (SAR) imagery collected from 2012 to 2016. The 3DSVF results show a vertical rate of 150 mm/yr and 40 mm/yr for the horizontal rate, where for the first time, the north component displacement is achieved by using only the Interferometric SAR time series in the CPGF. Data integration and validation between the 3DSVF and ground-based measurements such as continuous GPS time series and precise leveling data were achieved. Correlating the findings with recent geothermal energy production revealed a subsidence rate slowdown that aligns with the CPGF's annual vapor production. [ABSTRACT FROM AUTHOR]

Purpose: Existing literature lacks an analysis of factors predicting the achievement of minimum clinically important differences (MCID) after water vapor thermal therapy (WVTT) for prostatic hyperplasia. This study aims to identify these predictors over a 36-month post-WVTT period. Methods: This prospective single surgeon case series assessed male patients receiving WVTT. Eligibility criteria included being at least 45 years old, having an estimated prostate volume (EPV) of 30–80 cc, an International Prostate Symptom Score (IPSS) of 12 points or more, and a maximum urinary flow rate (Qmax) under 16 mL/sec. MCID, representing the smallest symptomatic improvement perceived by patients, was calculated using the distribution-based method, considering half a standard deviation of baseline IPSS scores. Correlation and linear regression analyses assessed MCID attainment. Multivariable logistic regression evaluated MCID achievement, considering multicollinearity, heteroskedasticity, and normality. Results: Of 206 men with a median 29.1-month follow-up (Range: 24–36), 13.6% didn't achieve MCID for IPSS, and 7.2% for QoL scores. Significant hindrances to MCID attainment for IPSS were a large median lobe (> 10 mm protrusion) (OR = 3.01, 95% CI: 2.3–3.72), increased median lobe treatments (OR = 1.73, 95% CI: 1.23–2.35), and high preoperative irritative IPSS scores (OR = 1.25, 95% CI: 1.13–1.38). Factors for QoL MCID non-achievement included age over 75 (OR = 1.25, 95% CI: 1.13–1.38), a large median lobe (OR = 1.87, 95% CI: 1.62–2.01), and EPV over 60 cc (OR = 1.55, 95% CI: 1.16–1.97). A 6.3% surgical re-intervention rate was noted. Conclusions: The characteristics of the median lobe as well as the severity of lower urinary tract symptoms are crucial for treatment success. These should be integral to preoperative assessments and patient discussions on treatment options. [ABSTRACT FROM AUTHOR]

In order to gain an in-depth understanding of the geothermal geological characteristics and heat-forming conditions in the Tangyuan fault-depression area, this paper has carried out a series of detailed geological works, including geological surveys and geophysical explorations. Through these works, combined with the results of systematic drilling, sampling tests, and dynamic monitoring, we have studied, analyzed, and compared the relevant data to achieve a comprehensive understanding of the geological characteristics in the Tangyuan fault-depression area. During the research process, we preliminarily determined the stratigraphic structure and geological structure in this area and clarified the characteristics of the main geothermal reservoir and its burial conditions. These findings provide basic data support for our understanding of the formation and distribution of geothermal resources. At the same time, we have carried out a systematic analysis of the basic geothermal geological parameters, laying the foundation for the future calculation and evaluation of geothermal resource reserves. Through the collation and analysis of these research results, this paper not only provides a scientific basis for the development of geothermal resources in the Tangyuan fault-depression area but also provides specific references for future development prospect plans. This series of work will lay a solid foundation for further development and utilization of geothermal resources and promote the sustainable development of the regional economy. [ABSTRACT FROM AUTHOR]

Introduction: Diving in SCUBA modality modifies human physiology in many ways. These modifications have been studied since Paul Bert in a seminal work. This area of research is very sensible to technological development. At now, it is possible to record heart rate (HR) continuously while diving. The study of HR changes in SCUBA diving at different depths in a constant temperature of thermal water is the objective of the present paper. Methods: 18 healthy subjects were enrolled and HR was recorded while SCUBA diving in thermal water at a constant temperature of 33.6°C in the deepest Italian pool at Montegrotto (Padova, Italy). Three depths were investigated: -20, -30 and -40 meters. The HR has been recorded with a Galileo SOL diving computer. The dive was subdivided into three phases: descent (DSC), steady on depth (STD), post-dive (RSF), and average HR was evaluated in each phase. Moreover, considering the DSC and STD time duration, a statistical linear regression of HR and relative parameters, intercept and slope, were here assessed. Results: In STD phase, HR slope obtained by regression decreased with depth. A significant difference was found between the slope during STD at -20 vs. -40 m (p = 0.05). Discussion: Present results emphasized different HR physiological adjustments among diving phases. Firstly, during the DSC, a rapid HR decrease is recognized as probably due to a vagal response; secondly, at STD, the inward blood redistribution requires another physiological adjustment. This latter is depth-dependent because of a reduction of cardiac variability. Present data highlight the important cardiac stress need to counteract the diving activity. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the feasibility of incorporating natural mineral waters (NMW), including thermal water (TW) and bottled mineral water (BMW), into bread ('biju' type) to enhance its mineral content and explore their impacts on physicochemical, technological, biochemical, and chemical composition. NMW, rich in sodium, potassium, and magnesium, resulted in bread formulations with higher contents of these minerals and greater total mineral levels, thus potentially enriching food products. Proximate composition analysis showed no significant differences in moisture, proteins, carbohydrates, and energy, except for lipids and soluble sugars. Texture analysis revealed that water type influenced textural properties, with salt content affecting hardness, springiness, and cohesiveness. Viability analysis of Saccharomyces cerevisiae showed consistent results across formulations, suggesting water pH and mineral content did not significantly affect fermentation. In addition, bread formulations without added salt were developed to assess the potential of sodium-rich NMW as a natural source of salt. For these samples, and considering the parameters assessed, except for salt and sodium content, the differences observed were slight compared to salt-added formulations, highlighting NMW's potential to produce low-salt bread. These findings not only enhance the value of local resources but also offer an innovative and sustainable strategy for utilizing NMW springs across Europe. [ABSTRACT FROM AUTHOR]

This paper discusses the opportunities and policy levers to increase the use of low-temperature geothermal resources in New Zealand for decarbonising primary industries, in particular, covered crops. Geothermal heat (geoheat) is a local, reliable, resilient and sustainable energy source. Low-temperature geothermal energy (220°C) is available in the Taupō Volcanic Zone with low awareness of the nationwide availability of lower temperature resources. Covered crop growers in New Zealand, needing to decarbonise their operations, are investigating the potential of utilising geoheat, following the example of the Netherlands. The Netherlands has strategically invested in low-temperature geothermal energy, utilising 80 °C water resources, from ∼ 2 to 3 km below the surface to heat greenhouses. Internationally, risk mitigation schemes and insurance programmes have proven pivotal policy instruments for fostering geothermal adoption. This paper discusses the opportunities that the adoption of using low-temperature geothermal provides to New Zealand drawing upon successful models from other countries. [ABSTRACT FROM AUTHOR]

This study aims to analyze the effect of Procurement Digitalization Capability, Collaborative Supply Chain Management, Operational Capability through Competitive Advantage on Sustainable Business Performance at Geothermal Energy Company Partners. The method used in this research is quantitative method, where this research uses surveys and questionnaires distributed to vendors or partners of the Geothermal Energy Company as the object of research. The research sample was selected using purposive sampling with the acquisition of 115 respondents. This study uses data testing methods using validity and reliability tests on each variable studied. While the data analysis method used in this research is the Structural Equation Model (SEM) with AMOS software. The results showed that the direct relationship between the Procurement Digitalization Capability variable had a positive effect on Competitive Advantage. Collaborative Supply Chain Management variables have no positive effect on Competitive Advantage. While Operational Capability has a positive effect on Competitive Advantage and finally Competitive Advantage has a significant positive effect on Sustainable Business Performance. Based on the results of this study, it is recommended for further research to be able to develop research in different industries and with a broader scope. [ABSTRACT FROM AUTHOR]

Lacustrine shale oil resources are essential for the maintenance of energy supply. Fluid types and contents play important roles in estimating resource potential and oil recovery from organic-rich shales. Precise identification of fluid types hosted in shale oil reservoir successions that are characterized by marked lithological heterogeneity from only a single well is a significant challenge. Although previous research has proposed a large number of methods for determining both porosity and fluid saturation, many can only be applied in limited situations, and several have limited accuracy. In this study, an advanced logging technique, combinable magnetic resonance logging (CMR-NG), is used to evaluate fluid types. Two-dimensional nuclear magnetic resonance (2D-NMR) experiments on reservoir rocks subject to different conditions (as received, after being dried at 105 ℃, and kerosene imbibed) were carried out to define the fluid types and classification criteria. Then, with the corresponding Rock–Eval pyrolysis parameters and various mineral contents from X-ray diffraction, the contribution of organic matter and mineral compositions was investigated. Subsequently, the content of different fluid types is calculated by CMR-NG (combinable magnetic resonance logging, viz. 2D NMR logging). According to the fluid classification criteria under experimental conditions and the production data, the most favorable model and optimal solution for logging evaluation was selected. Finally, fluid saturations of the Cretaceous Qingshankou Formation in the Gulong Sag were calculated for a single well. Results show that six fluid types (kerogen-bitumen-group OH, irreducible oil, movable oil, clay-bound water, irreducible water, and movable water) can be recognized through the applied 2D NMR test. The kerogen-bitumen-group OH was mostly affected by pyrolysis hydrocarbon (S2) and irreducible oil by soluble hydrocarbon (S1). However, kerogen-bitumen-group OH and clay-bound water cannot be detected by CMR-NG due to the effects of underground environmental conditions on the instruments. Strata Q8–Q9 of the Qing 2 member of the cretaceous Qingshankou Formation are the most favorable layers of shale oil. This research provides insights into the factors controlling fluid types and contents; it provides guidance in the exploration and development of unconventional resources, for example, for geothermal and carbon capture, utilization, and storage reservoirs. [ABSTRACT FROM AUTHOR]

The geochemical alteration of host rocks might affect the productivity and the potential for induced seismicity of geothermal systems. In addition to natural alteration, following production and heat extraction, re‐injected fluids at lower temperatures and different pressures may be in chemical disequilibrium with the rock, impacting mineral solubility and dissolution/precipitation processes. In this study, we investigate the effect of geochemical alteration on the frictional behavior of granites, and their seismogenic potential, by conducting direct shear experiments using samples with varying degrees of alteration. The samples originate from the Carnmenellis granite in Cornwall, SW England, and represent the formation used in the United Downs Deep Geothermal Power Project for heat extraction. Experiments were conducted on granite powders (referred to as gouges) at room temperature and 180°C, at simulated in situ confining and pore pressures of 130 and 50 MPa, respectively (∼5 km depth). With increasing degree of alteration, the frictional strength of the gouges decreases while frictional stability increases. At high temperature, frictional stability is reduced for all samples while maintaining the trend with alteration stage. Microstructural investigation of the sheared gouges shows alteration delocalizes shear by reducing grain size and increasing clay fraction, which promotes the formation of pervasive shear fabrics. Our work suggests that, within the range of tested pressures, more alteration of granite initially causes more stable shearing in a fault. This behavior with alteration is sustained at high temperatures, but the overall frictional stability is reduced which increases the potential for induced seismicity at higher temperatures. Plain Language Summary: Geothermal systems are of high interest as renewable energy source. However, hot fluids in the deep subsurface can chemically react with the host rock they flow through. These reactions then affect the fluid chemistry and the rock mineral composition. With changes in mineral composition, changes in mechanical and hydraulic properties are observed. We test the effects of a specific group of reactions (argillic alteration) on the frictional properties of granite powders by using an example rock that is targeted in geothermal projects in Cornwall, SW England. The frictional properties give information about how likely it is for granitic rocks to produce an earthquake while sliding. Our tests show that the more the granite has chemically changed, the easier the powder is to slide but the more stably it will slide. This means that chemically changed powders are less likely to create seismic waves on sliding. In addition, tests at high temperature (180°C) showed the same stabilizing effect within the reacted rocks but the general sliding stability was reduced over all samples. This implies that the potential for earthquakes is higher at higher temperatures, although the analyzed chemical reactions reduce this potential in granitic geothermal systems. Key Points: Large fault systems are targeted at depth as geothermal reservoirs in high‐heat producing granites in CornwallDirect shear experiments were conducted on a series of successively more naturally altered granites from a fault in Carnmenellis graniteAlteration makes sliding more likely but also more stable, while higher temperatures destabilize shearing [ABSTRACT FROM AUTHOR]

Transitioning to low-carbon energy systems is crucial for sustainable development, particularly in oil-rich developing countries (ORDCs) that face intertwined economic and environmental challenges. This review uses the PRISMA methodology to systematically assess the current state and prospects of low-carbon thermal electricity generation and utilization technologies in ORDCs. The study emphasizes clean thermal technologies such as biogas, biofuels, biomass, hydrogen, and geothermal energy, focusing on solutions that are technically feasible, economically viable, and efficient in combustion processes. These nations face significant challenges, including heavy reliance on fossil fuels, transmission losses, and financial constraints, making energy diversification urgent. The global shift towards renewable energy and the need to mitigate climate change presents an opportunity to adopt low-carbon solutions that align with Sustainable Development Goals related to energy access, economic growth, and climate action. This review aims to (1) evaluate the current state of low-carbon thermal electricity technologies, (2) analyze the technical and economic challenges related to combustion processes and energy efficiency, and (3) provide recommendations for research and policy initiatives to advance the transition toward sustainable thermal energy systems in ORDCs. The review highlights practical approaches for diversifying energy sources in these nations, focusing on overcoming existing barriers and supporting the implementation of clean thermal technologies. [ABSTRACT FROM AUTHOR]

(1) Introduction: Topical dithranol is still commonly used today as an effective treatment for psoriasis. Dithranol treatment is often supplemented with balneotherapy, which has been shown to increase effectiveness and reduce side effects. The inorganic salts (sulfhide, selenium, zinc) are usually thought to be responsible for the effect. The antioxidant effect of the waters is thought to be behind the therapeutic effect, for which inorganic substances (sulfides, selenium, zinc) are thought to be responsible. The organic matter content of medicinal waters is also particularly important, as humic acids, which are often found in medicinal waters, have antioxidant effects. (2) Methods: In this short-term experiment, we aimed to test the possible protective effect of Szigetvár medicinal water and its organic matter isolate on HaCaT cells exposed to dithranol. Malondialdehyde levels were measured, and RT-qPCR was used to investigate the gene expression of selected cytokines relevant in the oxidative stress response (IL-6, IL-8, TNF-α, GM-CSF) and the expression of microRNA-21. (3) Results: Szigetvár medicinal water and the organic isolate prevented the increase in malondialdehyde levels caused by dithranol treatment. The cytokine gene expressions elevated by dithranol exposure were reduced by the treatment. (4) Conclusions: Szigetvár medicinal water and organic substances alone may have a protective effect on patients' healthy skin surfaces against dithranol damage. We also demonstrated that the organic compounds are also responsible for the protective effect. [ABSTRACT FROM AUTHOR]

Various working fluids are applied during geothermal reservoir development, and geothermal reservoir damage induced by contacts between working fluids and reservoir formations are inevitable. Reservoir damage mechanisms, including solid and colloidal plugging, fluid sensitivity, stress sensitivity, and water locking, provide guidance for designing reservoir protection working fluids. In this paper, based on the design principles of reservoir protection working fluids applied in oil–gas reservoirs, four design principles of reservoir protection working fluids are proposed to eliminate potential geothermal reservoir damage for geothermal reservoirs, containing solid-free, facilitated flowback, temporary plugging, and inhibition. Solid-free is achieved by replacing solids with polymers in working fluids. Surfactant and materials with low affinity towards rock surfaces are applied for the facilitated flowback of working fluids from reservoir formations. Temporary plugging is achieved by using temporary plugging materials, some of which are polymers that also apply to solid-free working fluids. Besides, some of the temporary plugging materials, such as surfactant, are applicable for both the facilitated flowback and inhibition of working fluids. The inhibition of working fluids include the inhibition of clay minerals, which can be attributed to clay mineral inhibitors or activity regulators in working fluids, as well as the inhibition of mineral precipitations. This review aims to provide insights for geothermal reservoir protection working fluids, contributing to achieving an efficient development of geothermal resources. [ABSTRACT FROM AUTHOR]

Renewable energy sources play a vital role in the energy mix with geothermal energy providing an opportunity to harness the natural heat coming from the Earth for sustainable power production. As innovative drilling technologies come to market, it is easier to extract heat from various localities across the globe, leading to significant development in the geothermal sector. The economic viability of this resource can be significantly impacted when energy output declines due to scale deposition. Scale formation is a major challenge in the exploitation of geothermal wells, particularly in liquid-dominated geothermal fields. One of the most robust forms of scale build-up common to higher temperature geothermal wellbores and surface equipment for power production is silica scaling. Silica is one of the Earth's most abundant elements that can precipitate from brine due to various factors. The accumulation of scale deposits significantly impacts the lifespan and efficiency of surface equipment and geothermal wells by restricting fluid flow, thus reducing efficiency and performance. To guarantee the peak performance and longevity of geothermal systems, it is essential to implement a strategic maintenance plan for scaling reduction in geothermal systems. Throughout this review, relevant case studies highlight scaling reduction methods for silica scale in subsurface wellbores and surface facilities. [ABSTRACT FROM AUTHOR]

The Nanping geothermal field in Hainan is situated within the Wuzhi Mountain fold belt of the South China fold system based on its geotectonic units. Although there is abundant surface heat detected and widespread distribution of Late Mesozoic granite in the area, the geological background of geothermal resources remains unclear. In this article, we collected core samples from boreholes within the Nanping geothermal field to conduct testing and analysis on rock thermal conductivity and heat-production rate. By combining these results with temperature logging data, we discuss a method for diterming the heat flow background of convective geothermal system. Furthermore, the study analyzed the geothermal flux and deep thermal structure of the research area. The results demonstrate that the average radioactive heat production rate of the Baocheng rock mass in the study area is 3.16 μW/m³, primarily attributed to the decay heat of Th and U, while the heat contribution of K is negligible. The thermal conductivity values of the rocks are relatively high, ranging from 2.29 to 3.75 W/(mK), slightly exceeding the average thermal conductivity of the upper crust. The study area represents a typical convective geothermal field influenced by groundwater convection, exhibiting a high geothermal temperature gradient. Using the groundwater-correction method, the geothermal flux in the study area is calculated to be 89–108.27 mW/m², of which the thermal conduction component is 73.17 mW/m² and the convective component is 15.83–35.1 mW/m². Among these components, heat generated from radioactive decay of crustal radioactive elements contributes 35.44 mW/m² to thermal conduction, while deep mantle conduction accounts for a heat flux is 37.73 mW/m², with a ratio of 1:1.07 between them. The difference between crustal and mantle heat fluxes is minimal in this region, indicating an approximation towards a "crust-mantle heat source balance zone". Furthermore, the thickness of the "hot" lithosphere in the study area ranges from 42 to 46 km, indicating significant characteristics of extension-thinning. [ABSTRACT FROM AUTHOR]

The Salton Sea has experienced significant recession over the past two decades due to changes in the diversion of Colorado River water to the Salton Trough for agricultural irrigation. As a result, wetlands have emerged in some exposed playa areas along the Salton Sea, primarily in regions with extensive agricultural return flows and agricultural drainage. One notable wetland system, known as the Bombay Beach Wetlands, has formed on the north shore of the Salton Sea, in an area devoid of agriculture. In many other areas with limited or no agriculture, wetlands have failed to develop, leaving exposed playa surfaces as the Salton Sea recedes. These dry playa surfaces pose a significant threat to the health of local residents due to the presence of toxins contained in windblown dust associated with playa deposits. In this study, stable water isotope data, combined with other hydrological information, led to identification of two potential water sources for the Bombay Beach Wetlands. The first possibility proposes that thermal artesian waters alone contribute to the wetlands' water source, while the second hypothesis involves a combination of drainage from Salton Sea bank storage water mixing with the thermal artesian water. The thermal artesian water discharges into drainage channels that flow towards the Bombay Beach Wetlands, initially devoid of possible groundwater baseflow until reaching the wetlands. Studies were subsequently done along the full reach of the drainage channels receiving thermal artesian water. Dissolved solids content, P and N nutrients, arsenic, and stable water isotopes were tested synoptically along the drainage channels. Channel investigations led to the development of a novel model of salinization, which is linked to channel discharge, channel morphometrics, and channel incision. [ABSTRACT FROM AUTHOR]

Deep geothermal drilling is a necessary technological stage to produce renewable energy by "enhanced geothermal systems" everywhere. However, the high cost and complexity of deep drilling through hard rock formations is a major barrier to its commercialization. One approach to reach affordability and reduce the cost of deep drilling is to use millimeter-wave (mmw) gyrotron radiation to melt or vaporize rocks. In this paper, the results of an experimental study of mmw radiation absorption by hard rocks are presented. Electromagnetic attenuation and reflection were measured in W-band at frequencies from 75 to 110 GHz in eight rock samples from six different geological formations originated in Israel. The results show that the mmw radiation absorption in hard rocks ranges from 90 to 99% per centimeter. The absorption varies slightly with rock type and is relatively independent of frequency but has reached higher values at the upper W band for all samples. The study suggests that high-power mmw radiation is a promising technology for deep geothermal drilling. The results of this experiment, attenuation, and reflection of W-band radiation in hard rocks provide valuable information for the design and optimization of mmw-based drilling systems, and will support the design and optimization of gyrotron based hard rock drilling equipment for geothermal applications. [ABSTRACT FROM AUTHOR]

Global climate change highlights the significance of renewable clean energy. Geothermal energy from oilfields is abundant and can be utilized for residential heating and oil transportation. However, unreasonable heat exchange methods lead to groundwater level decline. Differences and delays between water extraction and reinjection inevitably cause land subsidence, hindering the sustainable utilization of geothermal energy resources. It is crucial to effectively monitor large-scale ground surface deformation characteristics in geothermal fields. In the research, 55 Sentinel-1A images from October 2018 to May 2022 were collected, and the ground deformation of Caofeidian new district in Bohai Bay Basin, where Nanpu Oilfield is located, in North China, was inverted by short baseline subsets-interferometric synthetic aperture radar (SBAS-InSAR) technology. The maximum subsidence velocity in Caofeidian new district exceeded 50 mm/year. Since April 2019, there has been concentrated ground subsidence in the Caofeidian new district, with a maximum cumulative subsidence exceeding 50 mm. The maximum cumulative subsidence exceeded 150 mm by May 2022. Combined with pumping and recharging tests near heating project in Caofeidian new district, the temporal subsidence mechanisms were revealed. The water extraction from the thermal reservoir caused drainage consolidation of the strata, triggering rapid subsidence in November. In April, discrepancy between water extraction and reinjection flow rate in thermal reservoir caused drainage consolidation of the strata, further exacerbating the subsidence trend. During rainy seasons, despite water reinjection and groundwater replenishment from precipitation, the strata in the Caofeidian new district underwent irreversible plastic deformation, with a slow rebound process, lagging behind urban areas without geothermal development by one month. InSAR is a reliable technology for understanding the ground deformation process in geothermal fields. Clarifying the subsidence mechanisms guides the selection of water-heat exchange methods, ensuring the sustainable development of geothermal resources. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine the Engineering students' knowledge on Renewable Energy (RE) resources. An online survey through proving Google form was conducted by using descriptive methodology. The participants for the survey were the engineering undergraduate students from Military Institute of Science and Technology (MIST), Dhaka, Bangladesh. A set of e-questionnaire with 19 items including 4 demographic and 15 knowledge measuring items was developed to collect data from the MIST undergraduate students. A total of 153 students responded to the survey. The demographic results indicated that male students of first and third study year with 20 to 30 years of age range from mechanical or industrial and production-engineering fields of study are the maximum respondents to the survey of this study. The main findings of the study highlighted that engineering students at MIST possess a higher level of understanding about various aspects of renewable energy, including solar energy, geothermal energy, wind energy, biogas energy, laws and policies of renewable energy (RE), establishment of RE, sources of information for RE, and the application of renewable energy in Bangladesh. Since the mean score for the questions was 3.72, reflecting a knowledge level between neutrality and agreement, the majority of the students responded positively to all the questions, indicating their strong grasp of these topics. The results also revealed that female students had a good understanding of renewable energy compared to male students, with an average score of 3.83 for females and 3.69 for males. Additionally, the study found that 3rd-year students displayed the highest level of understanding, while 1st-year students exhibited the lowest level of comprehension regarding renewable energy resources. [ABSTRACT FROM AUTHOR]

Shallow geothermal energy systems (SGES) are a promising technology for contributing to the decarbonization of the energy sector. Soil thermal conductivity (λ) governs the heat transfer process in ground under a steady state; thereby, it is a key parameter for SGES performance. Soil mixing technology has been successful in enhancing the shear strength of soils, but is adopted in this paper for the first time to improve soils as a geothermal energy conductive medium for SGES applications. First, the thermal conductivity of six types of soils was systematically investigated and the key parameters analyzed. Next, graphite-based conductive cement grout was developed and mixed with the six soils in a controlled laboratory setting to demonstrate the significant increase in soil thermal conductivity. For example, the thermal conductivity of a very silty dry sand increased from 0.19 to 2.62 W/m·K (a remarkable 14-fold increase) when mixed with the conductive grout at a soil-to-grout ratio of 6∶1. In addition, the mechanical properties of the cement grouts and cement-mixed soils were examined along with the microstructural analysis, revealing the mechanism behind the thermal conductivity improvement. [ABSTRACT FROM AUTHOR]

Renewable energy is one of environmentally friendly strategies to reduce the environmental pollution caused by energy generation from fossil fuels and reach sustainable development. In this current study, a geothermal driven multi-generation system to provide power, heating, freshwater, hydrogen and oxygen demands is investigated. The main components are encompassed single-pressure organic Rankine cycle, reverse osmosis desalination unit, domestic water heater and proton exchange membrane electrolyzer. For this purpose, energy, exergy, economic and exergoenvironmental (4E) evaluations are accomplished upon proposed system. Non-dominant sorting genetic algorithm has been considered as optimization method that leads to reveal the maximum and minimum of exergy efficiency and total annual cost (TAC) rate as two objective functions. In addition, sensitivity analysis is performed to reveal the roles of design parameters on the system performance and productivity from different standpoints. The optimal results showed that exergy efficiency and TAC increased, as operating temperature of PEM electrolyzer enhances. In terms of economic analysis, the most percentage of total investment cost is pertained to RO unit which was 58.05%. In addition, exergy efficiency and TAC of the proposed system were 30.42% and 255.96 $/h, respectively. As well, the mass flow rate of freshwater, hydrogen, oxygen, net power output and heating production were obtained 3146.7 m3/day, 0.42 m3/day, 3.35 m3/day, 1556.2 kW and 18,586 kW, respectively. Furthermore, by taking into account exergoenvironmental analysis, the environmental impact rate of power, heating, freshwater and hydrogen–oxygen production 2.331 × 10−5 pts/kJh, 3.668 × 10−3 pts/kJh, 1.45 pts/m3h and 11.42 pts/kgh, respectively. Eventually, the optimal outcomes from various perspectives were compared and argued. [ABSTRACT FROM AUTHOR]

Currently, the proportion of enterprise self-owned power plants (SPPs) is increasing, with a significant share occupied by small coal-fired units, severely affecting the absorption of new energy and causing substantial pollution. To address this issue, developing generation rights trading between SPPs and new energy enterprises is an effective solution. At present, research on generation rights trading is mainly based on early water and thermal generation rights replacement trading. This approach, to some extent, overlooks changes in electricity market policies. Based on this, a new generation rights trading bidding strategy incorporating price differences and time-of-use pricing settlement is proposed. Firstly, the relationship between price difference settlement and generation rights trading is studied and the win–win model of generation rights trading is improved. Secondly, in the time-of-use pricing settlement mode, the single bidding strategy is optimized with the objective of maximizing the total social benefits in the win–win model. Finally, an example analysis compares different bidding strategies under time-of-use pricing settlement. Even in the most extreme cases, the time-of-use bidding strategy can improve social benefits by 5.61% and reduce wind and solar curtailment by 7.25% compared to the single bid strategy. The results show that the optimized time-of-use bidding strategy significantly improves the efficiency of generation rights trading, greatly helping to promote the absorption of new energy and alleviate wind and solar power curtailment. [ABSTRACT FROM AUTHOR]

With the global expansion of geothermal energy, accurate prediction of pressure and temperature during drilling has become essential for ensuring the safety and efficiency of geothermal wells. Traditional numerical methods, however, often struggle to handle complex wellbore environments due to their high data demands and limited computational accuracy. To address these challenges, this paper introduces an innovative predictive model based on Physics-Informed Neural Networks (PINNs). By integrating physical laws with deep learning, the model theoretically surpasses the limitations of conventional methods. Trained on pressure and temperature data from a geothermal well in the Xiong'an area, the model demonstrates exceptional accuracy and robustness. Additionally, the model was rigorously tested under extreme wellbore conditions, showcasing its strong generalization capabilities. The findings suggest that PINNs offer a highly advantageous solution for geothermal drilling, with significant potential for practical engineering applications. [ABSTRACT FROM AUTHOR]

Hydrothermal resources are used for health prevention and treatment worldwide based on drinking, bathing, and immersing in thermal mineral waters. In some places, 222Rn inhalation is also present. In Brazil, several locations apply thermal and hydrotherapies integrated into the Unified Health System as in Águas de Lindóia and Thermas Antonio Carlos in Poços de Caldas Town. The effective dose due to 222Rn inhalation by the public and balneary workers, as well as the chemical and radiological characterization for these spas were evaluated. 222Rn activity concentration was measured by using CR-39, elemental water composition by neutron activation, and radionuclides, by gamma espectrometry. Results showed that the 222Rn activity concentration varied from 21 to 71 Bq m−3 in the public areas of the balnearies and from 407 to 16,451 Bq m−3 in the closed springs. Effective doses varied from 0.01 to 0.02 mSv y−1 for the public, from 0.10 to 0.33 mSv y−1 for works and from 0.03 to 4.95 mSv y−1 for maintenance. No risk occurs for members of the public and workers due to radon inhalation, but care must be taken on behalf of the maintenance workers from Águas de Lindóia balneary. The water, for both balnearies, do not exceed the recommendation for drinking water for gross alpha and gross beta activities. Chemically, the water from Águas de Lindóia is classified as hypo saline and the water from Poços de Caldas, as low mineral content. [ABSTRACT FROM AUTHOR]

The circulation depth of geothermal water providing the geothermal system framework significantly dominates the evaluation of renewal capacity and geothermal resources. The traditional evaluation of circulation depth is based on the groundwater temperature variation in the recharge section and the average geothermal heating rate of geothermal system. However, misunderstanding groundwater temperature distribution in geothermal systems will lead to overestimating groundwater circulation depth based on the recharge section. Temperature measurement in a 1000 m geothermal scientific borehole from the Xinzhou geothermal field of south China is discussed as a case study to reassess the circulation depth of geothermal water. For Xinzhou geothermal system, the recharge and discharge temperatures are from 26.2 °C to 32.6 °C and from 67.0 °C to 98.0 °C, respectively. And the heat exchange temperature at the deepest point is from 121 ℃ to 154 ℃. This indicates that the temperature gradient in the recharge section should be greater than that in the discharge section. But the actual observation is opposite that the temperature gradient in the recharge section and in the discharge section is 3.04 ℃/100 m and 4.97 ℃/100 m, respectively. We proposed that the depth of geothermal water circulation evaluated by the temperature change and the geothermal heating rate in the discharge section represents the top depth of convection in the heat exchange zone, and the depth evaluated by the recharge section represents the advection depth of groundwater in the recharge section. The top depth of convection in the heat exchange zone estimated by the discharge Sect. (0.75–1.49 km) is much shallower than the advection depth of groundwater in the recharge Sect. (3.25–4.34 km). In the convective heat exchange zone (between 4.34 km and 1.49 km), the fault zone at a certain depth is the ideal location for geothermal development to extract water and heat. [ABSTRACT FROM AUTHOR]