Source Characteristics Research Articles

The Development and Optimization of a New Wind Tunnel Design for Odour Sampling

The characterization of passive area sources, emitting odours due to wind-driven convection, poses significant challenges. The present experimental study aims to evaluate the performance, in terms of fluid dynamics and mass transfer, of a recently developed wind tunnel, with a more compact design and reduced weight, compared to the one proposed by the Italian regulations. The results show that the new design outperforms the Italian standard in several aspects. From a fluid dynamic point of view, the new wind tunnel exhibits a slightly more homogenous and uniform velocity distribution, and it does not reveal airflow preferential channels inside the central body. The pressure tests highlight that the presence of fillers in the new wind tunnel does not significantly alter the pressure inside the hood and therefore the gas–liquid equilibrium conditions; actually, the slight overpressure may help to prevent the infiltration of external air. Finally, mass transfer tests on the standard device show a vertical concentration gradient along the outlet duct, highlighting concentration values that differ up to a factor of two depending on the measurement point. The new design has almost completely solved this issue, thanks to the use of fillers that promote mixing of the outlet flow.

Petrogenesis of Early Permian within-plate-type gabbros in the Western Qiangtang Terrane, Tibet: partial melting of lithospheric mantle metasomatized by subducted oceanic sediments on the northern margin of the Gondwana

ABSTRACT The extensively distributed Early Permian mafic rocks in the Qiangtang Terrane of the central Tibetan Plateau are the magmatic records of separation of this terrane from the Gondwana. Nevertheless, the origins and mantle source characteristics of these rocks continue to be subjects of debate. This study reports zircon U-Pb and Lu-Hf isotopic and whole-rock geochemical and Sr-Nd-Hf isotopic data on gabbros exposed in the Zougou Region, western Qiangtang Terrane. Our zircon U-Pb isotope age suggests that the Zougou gabbros (ZGs) were formed at ca. 290 Ma, representing newly discovered Early Permian mafic rocks within the Qiangtang Terrane. The ZGs display geochemical affinities with within-plate-basalts given that they are tholeiitic and have high Zr/Y and Ti/V ratios. Compared to previously examined Early Permian mafic rocks in the western Qiangtang Terrane, the ZGs are characterized by their distinct, nonradiogenic Nd (εNd(t) = -0.54 to −2.18) isotopic signatures, which cannot be attributed to crustal contamination or assimilation. This assertion is supported by their uniform whole-rock εNd(t), εHf(t), and zircon εHf(t) values, as well as by magma mixing modelling. In conjunction with regional geology, we propose that the ZGs were derived from an isotopically enriched lithospheric mantle metasomatized by previous subduction events. Furthermore, the positive decoupling of Hf-Nd isotopes (ΔεHf(t) = +2.21 to + 2.72), negative Nb-Ta anomalies, and variable Ba/Th ratios within the ZGs indicate that the metasomatic agents were fluids released from oceanic sediments. Our study provides insights into the compositions of the lithospheric mantle beneath the Qiangtang Terrane during the Permian, which is pivotal to discriminating the role of asthenospheric and lithospheric components in the formation of the contemporaneous mafic rocks in response to Gondwana break-up.

Thermal characterisation of isotopic heat sources for enhanced thermophotovoltaic systems

Radioisotope thermophotovoltaics (RTPVs) are playing an increasingly important role in the energy supply for deep space exploration. The output performance of RTPVs can be significantly improved by increasing the surface temperature of isotopic heat sources and reducing the high-temperature degradation effect of the thermophotovoltaic cells. This work proposes methods such as selective emission coating and adjusting heat source structure to improve heat source temperature and optimize heat distribution. Results showed that the surface temperature of the heat source could generally reach more than 1000 K by using the selective coating when the thermal power of the isotopic heat source was 500 W. The use of selective coatings can also make the thermophotovoltaic cells closer to the heat source, and the volume of RTPVs could be reduced from 1.23 × 10−3 m3 to 0.49 × 10−3 m3, with a reduction of ∼60 %. Under the condition of W@SiO2 selective coating and 500 W heat source, RTPVs could produce the maximum output power of 22 mW/cm2 when the distance between the InGaAs cell and the heat source is 2 cm. The results provided effective guidance for the design of the heat source and miniaturization of RTPVs in space applications.

Assessment of Systematic Errors in Mapping Electricity Access Using Night-Time Lights: A Case Study of Rwanda and Kenya

Remotely sensed nighttime light data have become vital for electrification mapping in data-scarce regions. However, uncertainty persists regarding the veracity of these electrification maps. This study investigates how characteristics of electrified areas influence their detectability using nighttime lights. Utilizing a dataset comprising the locations, installation date, and electricity purchase history of thousands of electric meters and transformers from utilities in Rwanda and Kenya, we present a systematic error assessment of electrification maps produced with nighttime lights. Descriptive analysis is employed to offer empirical evidence that the likelihood of successfully identifying an electrified nighttime light pixel increases as characteristics including the time since electrification, the number of meters within a pixel, and the total annual electricity purchase of meters in a pixel increase. The performance of models trained on various temporal aggregations of nighttime light data (annual, quarterly, monthly, and daily) was compared, and it was determined that aggregation at the monthly level yielded the best results. Additionally, we investigate the transferability of electrification models across locations. Our findings reveal that models trained on data from Rwanda demonstrate strong transferability to Kenya, and vice versa, as indicated by balanced accuracies differing by less than 5% when additional data from the test location are included in the training set. Also, models developed with data from the centralized grid in East Africa were found to be useful for detecting areas electrified with off-grid systems in West Africa. This research provides valuable insight into the characterization of sources of nighttime lights and their utility for mapping electrification.

Characterization of recharge sources of the Miocene Fluvial Moghra aquifer in the North Western Desert of Egypt

Study regionThe Miocene Fluvial Moghra Aquifer in the North Western Desert of Egypt Study focusThe study integrates stable isotope analyses with aeromagnetic and hydrogeological datasets to accomplish the following: (1) define the primary source(s) of recharge to the Moghra aquifer, (2) assess aquifer connectivity with the Nile River aquifer, and (3) investigate the vertical connectivity of the Moghra aquifer with the underlying Nubian Aquifer System (NAS) through subvertical faults. New hydrological insights for the regionThe findings reveal (1) significant heterogeneity in groundwater isotopic compositions (Group A: δ18O: 1.1–13.8 ‰; δD: 4.6–73.5 ‰, B: δ18O:−0.99 to 0.85; δD: −7.58 to 4.38 ‰; and C: δ18O:−1.1 to −3.4; δD: − 6.3 to −18.2 ‰) indicative of variability in recharge sources. (2) Groundwater compositions west (up to 30 km) of the Nile River (Group A) resemble enriched modern Nile waters following the Aswan High Dam (AHD) construction that give way further west to relatively depleted groundwater (Group B) resembling historical pre-AHD Nile water compositions. (3) Further west from Group B depleted Group C samples occur along intersections of multiple fault systems (NW and NE-oriented faults) interpreted as mixtures of rising highly-depleted paleo Nubian Aquifer System (NAS) waters and pre-AHD Nile waters. (4) The advocated structural control is reported in similar settings in Egypt, suggesting that intersections of multiple fault systems provide regional connections between deep and shallow aquifers in northeast Africa, recharge overlying shallow aquifers, and should be considered in groundwater management scenarios.

Comparative analysis of winter composite-PM2.5 in Central Indo Gangetic Plain cities: Combined organic and inorganic source apportionment and characterization, with a focus on the photochemical age effect on secondary organic aerosol formation

To gain insights into air quality dynamics, a high-end instrument such as High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) alongside an Aethalometer was used to measure the Composite PM2.5 (C-PM2.5) in Lucknow and Kanpur during winter. It encompasses non-refractive PM2.5 (NR-PM2.5) and Black Carbon (BC) mass concentrations. Significant variation was noted in average C-PM2.5 concentrations at both sites, as 168.8 ± 61.3 μg m−3 in Lucknow and 90.7 ± 25.7 μg m−3 in Kanpur. Organics emerged as the predominant component, constituting ∼55%–65% of the C-PM2.5 mass, followed by inorganics (24% and 30%) and BC (20% and 8%). The present study employs Positive Matrix Factorization (PMF) on combined organic and inorganic source apportionment, resolving eight and seven source factors at Lucknow and Kanpur, respectively. Both sites exhibit significant contributions from solid-fuel combustion organic aerosol (SFC-OA), with ∼11% in Lucknow and 8% in Kanpur. However, SFC-OA mass concentration in Lucknow, at 24.67 μg m-³, is nearly double that in Kanpur (12.05 μg m-³). This was likely due to domestic coal burning in the nearby households, unregulated open burning, and burning of garbage on roadsides. The study shows that both sites were affected by oxidized biomass burning OA (O-BBOA) emissions, with increased concentration during the night due to dark oxidation by NO3 radicals. The diurnal variation of secondary organic aerosols (SOA), such as O-BBOA and semi-volatile oxygenated OA (SVOOA), shows increasing concentration during daytime hours. Therefore, the photochemical aging (ta) role in SOA formation was analyzed, and it was revealed that the formation might primarily be driven by photochemical oxidation. Additionally, two inorganic-rich factors, sulfate and nitrate-related OA (SO4-OA and NO3-OA) at both sites and additional ammonium chloride-related OA (NH4Cl-OA) resolved at Lucknow. Our study shows that NO3-OA and SO4-OA formation was dominated by aqueous phase processes due to high relative humidity and decline in concentration with increasing ta (ta > 30 h) during winter.

EXTRACTION OF PURE ALUMINA FROM KAOLIN: A REVIEW

This study demonstrated that high-purity alumina can be generated from kaolin using various methods. It examined different leaching techniques, considering the size and percentage recovery of alumina by weight in selected kaolin samples, the calcination temperature, and the molar concentration of acids over time. Additionally, it analyzed the characteristics of several kaolin sources in Nigeria with the aim of extracting alumina. The research indicates that Nigerian kaolinite clay typically contains 22–40% alumina by weight. However, leaching kaolin yielded alumina with a purity of 60–97 wt%, with particle sizes ranging from 16 to 177 nm. Alumina derived from kaolin is deemed beneficial for manufacturing refractory materials, water purification, and biomedical applications.

Parent-to-parent Advising: Conveying Advice Characteristics in an Online Group for Parents of Adolescents and Emerging Adults

In the context of parent-to-parent advising in an online social network site for parents of adolescents and emerging adults, this mixed methods study examined how and how often advisors conveyed known and now-introduced advice source and message characteristics. Results indicated that while some common advice variables were frequently conveyed (i.e. advisor similarity and expertise), other commonly used offline message variables (decision confirmation and clarifying questions) were not. Conveyed most frequently, however, were variables not previously examined in advice theorizing—empowering, encouraging, and modeling.

Trace element abundances in mineral phases and the groundmass of ocean island basalts

Incompatible trace elements are important tracers in igneous petrogenesis for determining processes acting: (i) prior to partial melting on magma sources; (ii) during partial melting, fractional crystallization or contamination of magmas, and (iii) after emplacement of lavas or intrusive rocks close to Earth's surface. Of particular interest are the high field strength elements (HFSE: Ti, Zr, Nb, Hf, Ta) which are incompatible elements with high valence states that are also relatively immobile in aqueous fluids. Abundances of Ti, Ta, and Nb (TITAN) in ocean island basalts (OIB) have been suggested to reflect recycled oceanic crust in mantle source regions, due to retention of these elements in subducted eclogitic rutile. Some of these elements have also been used to determine ‘canonical’ trace element ratios, such as Nb/U and Ta/U, that are considered invariant during petrogenetic processes. In this contribution, we present an extensive set of in situ trace element data for olivine, clinopyroxene, oxide minerals and groundmass for a suite of well-studied ocean island basalt (OIB) lavas from the Canary Islands, Azores, Samoa, Tubuai and La Réunion. The data were obtained using laser-ablation inductively coupled plasma mass spectrometry, and we also report a new open-source reduction routine for abundance determination using this method. Mineral-groundmass partitioning behavior is determined for olivine, clinopyroxene and oxides, showing that these are consistent with published partition coefficients for clinopyroxene and olivine, but are more variable for oxide phases. This variability is due to the wide variety of oxide phases possible in OIB (e.g., Cr-spinel, ilmenite, titanomagnetite) and their formation within the crystallization sequence. The new data shows that Nb and Ta budgets are dominated by fine-grained groundmass, as are most other incompatible trace elements, while the Ti budget is divided between clinopyroxene, oxide and groundmass. Modally reconstructed TITAN anomalies closely reproduce bulk rock compositions in samples with >40 % groundmass. Olivine and clinopyroxene fractional crystallization have negligible effects on TITAN anomalies, while oxide fractionation has more marked effects, with Ti anomalies being most affected. Variability in the HFSE in OIB and their association with other elements (e.g., Nb/U and Ta/U) can reflect source characteristics, although careful screening for petrogenetic effects should be done prior to ascribing significance to TITAN anomalies or canonical trace element ratios.

Numerical Simulation Analysis of Dock Bank Slopes’ Soil–Water Interface Recognition and Monitoring Device Models Based on Heat Transfer Principles

The erosion and sedimentation of bank slopes are important factors affecting the safety of wharf operations. The essence of bank slope monitoring is to identify the water–soil interface. This paper proposes a model for soil-and-water interface identification and monitoring equipment buried on the bank slope of the wharf, based on the difference in thermodynamic heat transfer between water and soil media, and presents the results of multi-condition numerical simulation. The comparison between numerical simulation results and indoor experimental results shows that the overall patterns are consistent, with an error of less than 11.4%, which is lower than the deviation between theoretical calculation results and indoor experiments. Based on the accuracy of the numerical calculation results, the temperature rise and propagation characteristics of linear heat sources made of iron and PVC in eight types of cohesive soils and six types of non-cohesive soils were studied. The results indicate that there are significant differences in the temperature distribution of linear heat sources made of iron and PVC in both water and soil media. The monitoring equipment model based on the difference in heat transfer between water and soil can be applied in practical engineering. This provides a foundation for the design and application of subsequent monitoring equipment.

Splitting intensity tomography to image depth-dependent seismic anisotropy patterns beneath the Italian Peninsula and surrounding regions

The region between central Europe and the centre of the Mediterranean is characterised by complex tectonics and kinematics. Here, the interaction between thickened crust, subducting lithosphere and surrounding asthenosphere produces strong and pervasive anisotropy in the upper mantle. Shear wave splitting measurements, the most adopted method to image seismic anisotropy so far, when interpreted in a ray-based framework result in little or no depth resolution, hampering a correct image of the anisotropy distribution with depth. In this study, we aim to better constrain the depth-dependent seismic anisotropy beneath Italy and surrounding regions, by isolating for the first time the source region of anisotropy at different depths. To do that, we perform an anisotropy tomography, adopting the splitting intensity inversion method. It is entirely based on the finite-frequency effect in the splitting of SKS waves. We first computed the splitting intensity using SKS waves recorded at all available permanent and temporary stations over the region, obtaining a huge dataset of measurements used as an input for the tomographic inversion. The large-scale 3D model of seismic anisotropy obtained with the inversion shows a clear change of anisotropy properties in terms of fast polarisation direction and intensity for different depths, thus improving the characterization of the main sources of anisotropy in the mantle as a function of depth. Shallower layers (70–100 km depth) are characterised by a complex and variable oriented pattern of anisotropy fast direction and intensity, which becomes progressively more organised with depth (100–300 km). This pattern suggests a strong control exerted by the geometry and motion of the different slab segments and the large-scale asthenospheric flow generated by subduction and roll-back processes. The strength of anisotropy increases with depth, with high values affecting the bulge of the Alps and Apennines chains and the southern Tyrrhenian subduction system. On the contrary, weaker anisotropy characterises the transition zone from the Apennines to Alpine domains beneath the Po plain, and both the Adriatic and European domains.

Multimethod characterization of geogenic sources of fluoride, arsenic, and uranium in Mexican groundwater

Geogenic groundwater F, As and U affect drinking-water availability and safety, with up to 60% of groundwater sources in some regions contaminated by more than recommended concentrations. As a result, an estimated 300–500 million people are at risk of severe health impacts and premature mortality. In the regions of Chihuahua, Zacatecas and Salinas, San Luis Potosí, Mexico (Sierra Madre Occidental), concentrations of fluoride (F), arsenic (As) and uranium (U) have been detected in groundwater above national and international drinking water standards. These elevated concentrations have been associated mainly with geogenic sources in volcanic rocks and basin fill sediments. However, the specific host phases and processes that release these toxic elements into groundwater have never been identified.In a new multi-method approach that combines classical approaches of hydrochemistry, petrography, and geochemistry, with more advanced techniques such as Raman spectroscopy (RS), scanning electron microscopy (SEM), electron microprobe (EMP) and laser ablation LA-ICP-MS, this research proposes an innovative methodology for the characterization and identification of F, As and U bearing phases in volcanic rocks and sediments, as well as some of the processes favoring the mobilization of these elements to groundwater. Groundwater chemical composition allowed the identification of 3 groundwater flow systems: a) local flows, hosted in basin-fill sediments with average temperatures of 21.7 °C, and low As (≈6.2 μg L−1), F (≈0.5 mg L−1) and U (≈1.1 μg L−1) concentrations; b) intermediate flows, characterized by average temperatures of 24.5 °C, and intermediate concentrations of As (≈17.7 μg L−1), F (≈1.1 mg L−1) and U (≈4.2 μg L−1); c) regional flows, circulating mainly through rhyolites and ignimbrites, temperatures that can reach up to 36.6 °C, and higher concentrations of As (≈36.5 μg L−1), F (≈2.6 mg L−1) and U (≈7.4 μg L−1). The presence and distribution of As, F and U in groundwater are associated with the local, intermediate and regional Tóthian flow systems proposed. Through microanalytical analyses, it was possible to identify F-rich minerals like fluorapatite (≈2.3 wt%), biotite (≈1.8 wt%) and fluorite (≈37 wt%). Glassy matrix rich in As (≈0.83–163 μg g−1), U (0.15–11.7 μg g−1) and F (200–1600 μg g−1) was mainly found in rhyolites and ignimbrites from the Tertiary volcanic outcrops of the tectonostratigraphic province of the Sierra Madre Occidental, and basin-fill sediments derived from these rocks. Based on the present study, the groundwater As, F, and U anomalies in the different study zones are associated with ignimbrites and rhyolites considered as their primary source, where processes like weathering, dissolution and devitrification, are directly linked to variations in the concentrations of these elements.This multi-method approach proposes a new efficient way to identify geogenic sources associated with F, As and U in groundwater, especially in regions where groundwater is the main source of supply. The outcome of this research can explain the possible reason behind the high concentrations of F, As and U in a number of regional groundwater flow systems which are well documented cases in volcanic regions of the world and Mexico. The results obtained through the analysis of water-rock interaction in this research can be applied to other semi-arid regions with geogenically impacted aquifers, due to the geological and climatic similarity with numerous volcano-sedimentary basins around the world.

Environmental changes in the Fleuve Manche paleoriver drainage system (Western Europe) linked to North Atlantic sub-millennial climate variability across Heinrich Stadial 1: Palynological evidence from the Bay of Biscay

Marine microfossils (dinoflagellate cysts and planktonic foraminifera) and geochemical (XRF-Ti/Ca)-based climatic records from a core (MD13–3438) located off the Fleuve Manche (FM) paleo-mouth have revealed that sustained warm summer sea surface temperatures (SSTs) during sub-millennial climate changes within HS1 (∼18–14.7 ka) may have played a key role in the FM regime related to the European Ice Sheet (EIS) melting rate. In this study, we have analyzed the MD13–3438 pollen content over the HS1 at a mean resolution of ∼50 years to test whether vegetation-based air temperatures were coupled to SSTs face to this rapid climate variability. First, our results highlight two major phases of pollen sources at site MD13–3438, preventing the pollen record to be interpreted as a continuous record of the evolution of vegetation and climate occupying a single watershed across HS1. The first phase, i.e. the HS1-a interval (∼18–16.8 ka), is marked by strong occurrences of boreal pollen taxa (especially Picea-Abies). Considering their spatial distribution and the coalescence of the British and Scandinavian ice sheets into the North Sea during the Last Glacial Maximum, these taxa probably originated from the North European Plain, i.e., eastern FM tributaries (east of the Rhine River), where cool-humid conditions generally prevailed. Then, the second phase, i.e. the HS1-b interval (∼16.8–14.7 ka BP), is characterized by a deceleration of the EIS retreat and the drop of boreal pollen values at site MD13–3438 further signing a less influence of the upstream FM drainage system and thus a better characterization of pollen sources related with western FM tributaries. Superimposed to these two HS1 main phases, pollen fluctuations are concomitant with sub-millennial variability in the EIS deglaciation intensity. During the early HS1 (HS1-a), we discuss two short-term increases in the ratio between deciduous trees (Quercus-Corylus-Alnus) and herbaceous plants (Plantago-Amaranthaceae-Artemisia). These events are coeval with phases of increasing dinocyst-based SST seasonality (i.e. through summer SST amplification). We associate these events with lower contribution of the upstream FM catchment as well as, possibly, atmospheric warming and regional sea-level positive oscillations. The HS1-b is composed of three main phases that appear more influenced by the downstream FM drainage system. HS1-b1 (16.8–16.3 ka BP) corresponds to the driest and coldest conditions west of the Rhine River. HS1-b2 (16.3–15.5 ka BP) is coeval with large arrivals of iceberg from the Hudson strait in the Bay of Biscay and thus likely to a major sea-level positive oscillation associated with a phase of FM valley reworking. HS1-b3 (15.5–14.7 ka BP) corresponds to persistent arid conditions that preceded the subsequent more humid conditions recorded from 14.7 ka BP at the start of the Bölling-Alleröd.

A theoretical framework for linking hospitals longitudinally: demonstrated using German Hospital Quality Reports 2016–2020

BackgroundIn longitudinal health services research, hospital identification using an ID code, often supplemented with several additional variables, lacks clarity regarding representativeness and variable influence. This study presents an operational method for hospital identity delimitation and a novel longitudinal identification approach, demonstrated using a case study.MethodsThe conceptualisation considers hospitals as evolving entities, identifying “similar enough” pairs across two time points using an automated similarity matrix. This method comprises key variable selection, similarity scoring, and tolerance threshold definition, tailored to data source characteristics and clinical relevance. This linking method is tested by applying the identification of minimum caseload requirements-related German hospitals, utilizing German Hospital Quality Reports (GHQR) 2016–2020.ResultsThe method achieved a success rate (min: 97.9% - max: 100%, mean: 99.9%) surpassing traditional hospital ID-code linkage (min: 91.5% - max: 98.8%, mean: 96.6%), with a remarkable 99% reduction in manual work through automation.ConclusionsThis method, rooted in a comprehensive understanding of hospital identities, offers an operational, automated, and customisable process serving diverse clinical topics. This approach has the advantage of simultaneously considering multiple variables and systematically observing temporal changes in hospitals. It also enhances the precision and efficiency of longitudinal hospital identification in health services research.

Statistical Identification of Independent Shocks with Kernel-based Maximum Likelihood Estimation and an Application to the Global Crude Oil Market

Independent component analysis has emerged as a promising approach for revealing structural relationships in multivariate dynamic systems, particularly in scenarios with limited knowledge of causal patterns. This article introduces a robust kernel-based maximum likelihood (KML) estimation method that accommodates the distributional characteristics of the structural sources of data variation. Our Monte Carlo study demonstrates the superior performance of the KML estimator compared to existing approaches for independence-based identification. Moreover, the proposed method enables partial identification and dimension reduction even in the presence of dependent shocks. We illustrate the benefits of our approach by applying it to the global oil market model of Kilian, highlighting its ability to capture unmodeled higher-order dependence between oil supply and speculative oil demand shocks.

Pollution source characterization and evaluation of groundwater quality utilizing an integrated approach of Water Quality Index, GIS and multivariate statistical analysis

ABSTRACT The Mid-Gangetic Plain, a vital farmland in India, faces increasing groundwater quality deterioration due to anthropogenic activities. This study aimed to assess groundwater quality and contamination sources in the region utilizing statistical methods. A total of 78 groundwater samples were collected and analyzed using standard methods. The hydrochemistry analysis of samples revealed that several parameters such as Ca2+, Mg2+, HCO3−, NO3−, F− and PO43− surpassed the limits prescribed by the Bureau of Indian Standards (BIS). The principal component analysis yielded three significant factors, explaining 68.96% variation, highlighting geogenic and anthropogenic influences on groundwater chemistry. Hierarchical cluster analysis categorized groundwater into three clusters based on the parameters with similar trends of variation. Furthermore, Discriminant analysis identified four significant variables (Mg2+, F−, Cl− and NO3−) responsible for creating the distinction among the identified clusters. Hydrogeochemical categorization and multivariate statistical analyses indicated that rock–water interaction, weathering, leaching and anthropogenic activities collectively influenced groundwater quality throughout the studied region. The Water Quality Index reveals that 59% of samples have good water quality, while 41% exhibit poor quality predominantly concentrated in the south-western, south-eastern and central regions. This study demonstrates the efficacy of statistical techniques to interpret complex datasets and grasp water quality dynamics, enhancing groundwater management.

Laser-Induced Periodic Surface Structures and Their Application for Gas Sensing.

Semiconducting metal oxides are widely used for solar cells, photo-catalysis, bio-active materials and gas sensors. Besides the material properties of the semiconductor being used, the specific surface topology of the sensors determines device performance. This study presents different approaches for increasing the sensing area of semiconducting metal oxide gas sensors. Micro- and nanopatterned laser-induced periodic surface structures (LIPSSs) are generated on silicon, Si/SiO2 and glass substrates. The surface morphologies of the fabricated samples are examined by FE SEM. We selected the nanostructuring and characterization of nanostructured source Ni/Au and Ti/Au films prepared on glass using laser ablation as the most suitable of the investigated approaches. Surface structures produced on glass by backside ablation provide 100 nm features with a high surface area; they are also transparent and have high resistivity. The value of the hydrogen sensitivity in the range concentrations from 100 to 500 ppm was recorded using transmittance measurements to be twice as great for the nanostructured target TiO2/Au as compared to the NiO/Au. It was found that such transparent materials present additional possibilities for producing optical gas sensors.

Regional characteristics of groundwater sulfate source and evolution in the multi-layer aquifer system of the northern Shaanxi coal mine base, northwestern China: Evidence from geochemical and isotopic fingerprints

Groundwater sulfate contamination in mining areas has attracted widespread attention. However, deciphering the source and evolution of sulfate in large-scale mining areas remains a challenge due to intense anthropogenic influences and complex hydrogeological conditions. In this study, 94 groundwater samples were analyzed by a combination of self-organizing maps, MixSiar model, multi-isotope analyses (δ34S, δ18OSO4, δD and δ18Owater) and hydrogeochemical methods to investigate the regional characteristics of groundwater sulfate source and evolution in China's largest coalfield (the Shenfuyu Coalfield). The results showed that the source and evolution of groundwater sulfate were controlled by human activities (mining and agricultural activities) and hydrogeological conditions. The groundwater sulfate primarily originated from pyrite oxidation, gypsum dissolution and human inputs. For the mining districts with shallow mining depths, pyrite oxidation and fertilizer contributed to groundwater sulfate. In addition, the ground cracks and abandoned mines controlled the BSR and pyrite oxidation processes. In contrast, the gypsum dissolution and cation exchange dominated the sulfate evolution in the mining districts with deep mining depths due to slow groundwater circulation. This study provided new insights into the source and evolution of groundwater sulfate in large coalfields, as well as references for regional water resource utilization and protection.

Where has hydrogeologic science been, and where is it going? Research trends in hydrogeology publishing over the past 60 years

AbstractQuantifying historical research trends in the field of hydrogeology is not only generally informative for hydrogeologists but is essential for fostering interdisciplinary collaboration and assessing the relationship between academic study and societal interests in hydrogeologic issues. To address this, a topic model was applied to over 37,000 academic abstracts published in over 20 journals between 1963–2022 in the field of hydrogeology to study the evolution of topic trends through time. Model results were fed into the popular large-language model ChatGPT to assign topic names, representing an unsupervised method. The results indicate that, historically, popular topics related to methodological development and analytical and numerical models analytical and numerical methods in groundwater flow modeling and well hydraulics have given way to topics related to more increasingly complex models (groundwater monitoring and uncertainty estimation and groundwater modeling calibration and simulation) as data and computational capability becomes increasingly available. An insight into the period of boom-and-bust in contaminant hydrogeology is reflected by a shift in focus from topics related to assessment and characterization of contaminant sources toward topics related to degradation and remediation methods. Topics of emerging prevalence (sustainable groundwater resource management, catchment hydrology and runoff processes) in the current period reflect an increasing focus on treating the surface-water/groundwater system as a single system. In addition, results suggest that topic distribution within the field of hydrogeology has become more varied as time has progressed.

PSX-2 Productive performance of Raramuri Criollo, Angus x Raramuri Criollo and Hereford x Angus cows in a low-input cow-calf system in northern Mexico

Abstract Raramuri Criollo cattle (RC), a local heritage breed in the Chihuahua state of Mexico, are highly rustic and well-adapted animals that can contribute to cow productivity in a low-input cow-calf production system. The aim was to evaluate traits related to productive performance of purebred RC, Angus x RC (AC) and Hereford x Angus (HA) cows. Each cow breed group was randomly assigned to one of three pastures within each of two mountains dominant exposures and evaluated during 2022 and 2023 at Rancho Teseachi (28◦48′ N, 107◦25′ W) belonging to Universidad Autonoma de Chihuahua. The six grazing pastures ranged from 263 to 400 ha, with similar slope, altitude and water sources characteristics. The stocking rate was moderate (forage utilization <50%). Forage biomass availability for the period of use was sampled in October, and stocking rate adjusted accordingly in March. RC cows were bred with RC bulls, and AC and HA with Angus bulls. The breeding season was from September to November, and pregnancy diagnosis at mid-January. Non-pregnant cows were replaced by pregnant cows from other pastures of the same farm. Feed supplementation was limited in 2022 and according to nutritional requirements in 2023. Evaluated variables included calf birth (BW) and weaning weight adjusted (WW) to the average age at weaning (190 d in 2022 and 165 d in 2023); body condition score (BCS 1 to 9), cow body weight (CBW) at the beginning of the breeding season, as well as body weight of calf weaned by unit of cow weight (WW/CBW), and pregnancy rate (PR). A general linear model with fixed effects of breed group, sex, dominant exposure of mountains, their interaction, cow age subclass (Young, 4 yr; Middle, 5 to 8 yr; Adult, > 9 yr) and Julian date at calving as a covariate was adjusted using PROC GLM of SAS for continuous, normally distributed variables, and PROC CATMOD for pregnancy rate, leaving out sex and interaction effects. Means of BW and WW on calves from AC and HA cows were greater (P < 0.5) than those from RC cows in both years (Table 1). In 2022, the mean CBW of HA was greater (P < 0.5) than for AC, and this greater (P < 0.5) than for RC cows; BCS was greater for AC than for HA and RC, and PR lower (P < 0.5) for HA than for AC and RC. In 2023, there was no difference in CBW between AC and HA; BCS was similar (P > 0.05) among the three groups; and PR was the lowest (P < 0.5) for HA. The AC cows had the greatest WW/CBW mean (P < 0.5) in both years. Overall, using AC cows resulted on a combination of traits that outperformed on general productivity in the evaluated production system.