bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ecohydrogeophysics at the Edwards Aquifer: insights from Polarimetric ground‐penetrating radar
Authors: Sassen Douglas S. , Everett Mark E. , Munster Clyde L. 
Published: September 2009

ABSTRACTThree‐dimensional multicomponent ground‐penetrating radar (GPR) reflection data and horizontal GPR transmission profiles were acquired and analyzed to better understand the interaction of vegetation with subsurface flow conduits at a hydrologic experimentation site. Previous researchers conducted a set of shallow (<2.5 m) subsurface hydrology experiments during simulated rainfall events within a small plot (7 m × 14 m) on the fractured and karsted limestone of the Edwards Aquifer region near San Antonio, Texas, USA, to better understand the influence of Juniperus ashei brush control on the local hydrology. Tracer experiments showed a high degree of variability in tracer recovery, advection speed and concentration depending on the location of the application of the tracer. Both 3D multicomponent GPR reflection images and coherency and inversion of GPR horizontal transmission profiles were utilized to identify the main conduits of flow within the experimentation site in order to explain the observations of the experiments. The 3D multicomponent GPR and coherency images revealed that the most obvious potential conduits run nearly parallel with the observation trench. Inversions of the horizontal transmission profiles indicate that some conduits are filled with soil while others have no fill. This information helps explain the high spatiotemporal variability observed in the tracer data. Additionally, the GPR and hydrologic experiments suggest that Juniperus ashei significantly impacts infiltration by redirecting flow towards its roots occupying fractures within the rock. This study demonstrates that GPR provides a noninvasive tool that can improve future subsurface ecohydrologic experimentation.
Hydrogeological prospecting using P‐ and S‐wave landstreamer seismic reflection methods
Authors: Pugin André J.‐M. , Pullan Susan E. , Hunter James A. , Oldenborger Greg A. 
Published: September 2009

ABSTRACTWe present two case histories from different areas and geological settings in Canada where we have used a vibrating seismic source coupled to a landstreamer receiver array in hydrogeological investigations related to aquifers in glacial sediments. In Manitoba, our P‐wave seismic reflection profiles are used to provide an assessment of the subsurface architecture of buried valleys, estimate the thickness and properties of both the channel fill and the overlying sediments to depths of ~100 m and locate optimum sites for groundwater well placements. In eastern Ontario, we collected P‐ and S‐wave seismic reflection as well as electrical resistivity data to investigate buried esker aquifers. The geophysical data provide detailed high‐resolution information (to ~30 m depth) on the structure of the esker core and its overlying sand cover and on the thickness and variability of the overlying fine‐grained aquitard. The data presented in this paper demonstrate that shallow seismic reflection methods are very effective tools to explore, assess and evaluate groundwater reservoirs and resources. The recent advent of landstreamer receiver arrays, especially when coupled to a vibratory seismic source, makes these methods significantly more cost‐effective and efficient. We now routinely collect ~1000 records/day, or 1.5‐6 line‐km/day, using our Minivib/landstreamer data acquisition system. With this type of efficient data collection, it is anticipated that the use of shallow seismic reflection methods in hydrogeological prospecting will increase as groundwater and its protection become more valued by society.
Monitoring freshwater‐seawater interface dynamics with audiomagnetotelluric data
Authors: Falgàs Ester , Ledo Juanjo , Marcuello Alex , Queralt Pilar 
Published: September 2009

ABSTRACTSaltwater intrusion is one of the main environmental concerns within coastal aquifers. In this study we test the audiomagnetotelluric (AMT) method as a technique that can detect changes in electrical resistivity as a result of seasonal groundwater salinity changes. AMT is a frequency domain electromagnetic induction technique ideally suited for hydrogeophysical investigations at the basin scale, specifically in low resistivity environments such as saltwater encroachments areas. We present numerical seawater intrusion models to explore the effects of saline content variability on the model resolution. Survey data were also acquired during a long‐term AMT monitoring experiment in a natural condition aquifer system and these results were compared to the numerical modelling results. The aquifer system is located in the deltaic zone of the Tordera River (north‐eastern of Iberian Peninsula), where a main paleochannel that works as a seawater intrusion path was already identified in previous studies. Every four months, between 2004 and 2006, seven AMT soundings were recorded along a 1700 m long profile over the paleochannel. The final models reveal dynamic changes in the seawater‐freshwater interface that correspond directly with the hydrologic state of the aquifer system.
The geophysical investigation of lake water seepage in the regulated environment of the Bosherston Lily Ponds, South Wales, UK. Part 1: natural, fracture‐related pathways
Authors: Husband Claire R. , Cassidy Nigel J. , Stimpson Ian G. 
Published: September 2009

ABSTRACTThe detection and characterization of hydrological pathways is applicable to many branches of geosciences including contaminant hydrogeology, mining, civil engineering and petroleum geology. Geological features play a critical role in fluid transportation through the presence of enhanced hydraulic conductivity pathways, although determining their exact contribution is difficult. This paper reports the results of geophysical investigations at the Bosheston Lily Ponds in Pembroke, South Wales, UK where the lake system has experienced unexplained water loss for over thirty years. The area is classified a Special Area of Conservation (SAC) and is managed under tight regulatory regime that limits the scope and extent of any site investigations. Geophysical surveys focused on identifying any natural hydraulic conduits/pathways in the underlying carboniferous limestone where the main objectives were to determine whether bedrock fracturing is promoting natural water loss. Ground‐penetrating radar (GPR), electrical resistance tomography (ERT) and self‐potential (SP) surveys were collected at targeted site locations and the information gained used to ascertain the nature of the observed/predicted lake water loss. The results show that localized zones of high‐density, small‐scale fracturing in the limestone bedrock are likely to be the predominant cause of lake water loss with little evidence of larger scaled, open karstic features.
A review of helicopter‐borne electromagnetic methods for groundwater exploration
Authors: Siemon Bernhard , Christiansen Anders Vest , Auken Esben 
Published: September 2009

ABSTRACTFor about three decades, airborne electromagnetic (AEM) systems have been used for groundwater exploration purposes. Airborne systems are appropriate for large‐scale and efficient groundwater surveying. Due to the dependency of the electrical conductivity on both the clay content of the host material and the mineralization of the water, electromagnetic systems are suitable for providing information about the aquifer structures and water quality, respectively.More helicopter than fixed‐wing systems are used in airborne groundwater surveys. Helicopter‐borne frequency‐domain electromagnetic (HEM) systems use a towed rigid‐boom. Helicopter‐borne time‐domain (HTEM) systems, which use a large transmitter loop and a small receiver within or above the transmitter, are generally designed for mineral exploration purposes but recent developments have made some of these systems usable for groundwater purposes as well.The quantity measured, the secondary magnetic field, depends on the subsurface conductivity distribution. Due to the skin‐effect, the penetration depths of the AEM fields depend on the system characteristics used: high‐frequency data/early‐time channels describe the shallower parts of the conducting subsurface and the low‐frequency data/late‐time channels the deeper parts. Typical investigation depths range from some ten metres (conductive grounds) to several hundred metres (resistive grounds), where the HEM systems are appropriate for shallow to medium deep (about 1–100 m) and the HTEM systems for medium deep to deep (about 10–400 m) investigations.Generally, the secondary field values are inverted into resistivities and depths using homogeneous or layered half‐space models. As the footprint of AEM systems is rather small, one‐dimensional interpretation of AEM data is sufficient in most cases and single‐site inversion procedures are widely used. Laterally constrained inversion of AEM data often improves the stability of the inversion models, particularly for noisy data. Higher dimensional inversion is still not possible for standard‐size surveys.Based on typical field examples the advantages as well as the limitations of AEM surveys compared to long‐established ground‐based geophysical methods used in groundwater surveys are discussed. In a case history from a German island an airborne frequency‐domain system is used to successfully locate freshwater lenses on top of saltwater. An example from Denmark shows how a time‐domain system is used to locate large‐scale buried structures forming ideal groundwater aquifers.
The geophysical investigation of lake water seepage in the regulated environment of the Bosherston Lily Ponds, South Wales, UK. Part 2: historical, dam‐related pathways
Authors: Husband Claire R. , Cassidy Nigel J. , Stimpson Ian G. 
Published: September 2009

ABSTRACTThe detection, characterization and assessment of water loss through hydrological pathways is an important aspect of civil, hydrological and environmental engineering. At any site, variations in the form and hydrological integrity of both natural and man‐made features can play a critical role in fluid transportation through the presence of enhanced hydraulic conductivity. Traditional hydrological and invasive engineering investigation methods are often unsuitable for ecologically sensitive environments and in this paper, we report the results of a non‐invasive hydro‐geophysical study at the Bosheston Lily Ponds in Pembroke, South Wales, UK, an area classified a Special Area of Conservation (SAC). For over 30 years, the lake system has experienced unexplained water loss and the geophysical surveys focused on identifying hydraulic conduits/pathways in the underlying carboniferous limestone and assessing the integrity of the man‐made dam structure at the outlet of the lake system. The site is managed under tight regulatory regime that limits the scope and extent of any hydrological/geophysical investigations. The main objectives were to determine whether bedrock fracturing is promoting natural water loss and, more pertinently, if structural failures in the modern (and original) dam structures were responsible for significant loss of water at the outlet of the lakes. Ground‐penetrating radar (GPR), electrical resistance tomography (ERT) and self‐potential (SP) surveys were collected at targeted sites and the information gained used to ascertain the nature of the observed/predicted lake water loss. The results show that both the modern and original dam appear to be intact, structurally sound and show no evidence for significant water flow through its structures. Instead, localized zones of natural, high‐density fracturing in the limestone bedrock appear to be the predominant cause of lake water loss.
Fast, laterally smooth inversion of airborne time‐domain electromagnetic data
Authors: Christensen Niels B. , Reid James E. , Halkjær Max 
Published: September 2009

ABSTRACTWe present a fully developed, fast approximate method for 1D inversion of time‐domain electromagnetic data. The method is applied to a helicopterborne transient electromagnetic data set from the Toolibin Lake area of Western Australia using the lateral parameter correlation method to ensure lateral smoothness of the inverted models.The method is based on fast approximate forward computation of transient electromagnetic step responses and their derivatives with respect to the model parameters of a 1D model. The inversion is carried out with multi‐layer models in an iterative, constrained least‐squares inversion formulation including explicit formulation of the model regularization through a model covariance matrix. The method is 50 times faster than conventional inversion for a layered earth model and produces model sections of concatenated 1D models and contoured maps of mean conductivity in depth intervals almost indistinguishable from those of conventional inversion.To ensure lateral smoothness of the model sections and to avoid spurious artefacts in the mean conductivity maps, the inversion is integrated with the lateral parameter correlation method. In this way, well determined parameters are allowed to influence the more poorly determined parameters in the survey area.Applied to the Toolibin data set, the inversion produces model sections and conductivity maps that reveal the distribution of conductivity in the area and thereby the distribution of salinity. This information is crucial for any remediation effort aimed at alleviating the salinization problems.
Development of a holistic wellness model for managers in tertiary institutions
Authors: Botha Petrus A. , Brand Hein 
Published: September 2009

Individuals struggle to attain optimal wellness and health levels due to unhealthy lifestyle behaviour. A holistic wellness model was developed in this study to provide a framework for a cross-sectional survey to assess the wellness behaviour and health risk levels of managers in two South African universities. A census was done on the total population of 324 and responses were received from 89 managers. The study employed descriptive and inferential statistical procedures to analyse the quantitative data. The findings suggested that the managers had high levels of wellness behaviour and low levels of health risks. Physical fitness and nutrition as well as medical self-care wellness behaviour levels were identified as weaknesses among managers, for which urgent interventions are required.
Scutellarin Attenuates Microglia Activation in LPS‐Induced BV‐2 Microglia via miRNA‐7036a/MAPT/PRKCG/ERK Axis
Authors: Duan Zhaoda , Yang Li , Xu Dongyao , Qi Zhi , Jia Wenji , Wu Chunyun 
Published: April 2024

AbstractScutellarin is an herbal agent which can exert anti‐neuroinflammatory effects in activated microglia. However, it remains uncertain if it can inhibit microglia‐mediated neuroinflammation by regulating miRNAs. This study sought to elucidate the upstream regulatory mechanisms by endogenous microRNAs and its target gene in activated microglia in lipopolysaccharide (LPS)‐induced BV‐2 microglia. Results show that scutellarin suppressed the expression of tumor necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), and inducible nitric oxide synthase (iNOS) significantly in LPS‐stimulated BV‐2 microglia. As with the results of miRNAs function classification in vitro, the expression levels of mir‐7036a‐5p are upregulated in LPS‐activated BV‐2 microglia, but are downregulated by scutellarin. Rescue experiments indicated that mir‐7036a‐5p is a pro‐inflammatory factor in activated BV‐2 microglia. mir‐7036a‐5p agomir promoted the expression of phosphorylated tau proteins (p‐tau), protein kinase C gamma type (PRKCG), extracellular regulated protein kinases (ERK1/2), but the is reversed by mir‐7036a‐5p antagomir in vitro. It is shown here that mir‐7036a‐5p is involved in microglia‐mediated inflammation in LPS‐induced BV‐2 microglia. More important is the novel finding that scutellarin mitigated microglia inflammation by down‐regulating the mir‐7036a‐5p/MAPT/PRKCG/ERK signaling pathway.
Tissue‐Engineered Microvessels: A Review of Current Engineering Strategies and Applications
Authors: Zhao Nan , Pessell Alexander F. , Zhu Ninghao , Searson Peter C. 
Published: April 2024

AbstractMicrovessels, including arterioles, capillaries, and venules, play an important role in regulating blood flow, enabling nutrient and waste exchange, and facilitating immune surveillance. Due to their important roles in maintaining normal function in human tissues, a substantial effort has been devoted to developing tissue‐engineered models to study endothelium‐related biology and pathology. Various engineering strategies have been developed to recapitulate the structural, cellular, and molecular hallmarks of native human microvessels in vitro. In this review, recent progress in engineering approaches, key components, and culture platforms for tissue‐engineered human microvessel models is summarized. Then, tissue‐specific models, and the major applications of tissue‐engineered microvessels in development, disease modeling, drug screening and delivery, and vascularization in tissue engineering, are reviewed. Finally, future research directions for the field are discussed.
Bioactive Profiling, Antibacterial Efficacy and Computational Modelling of Myrtus Communis Essential Oil (Morocco)
Authors: Hayani Mouhcine , Benabbouha Tariq , Naceiri Mrabti Nidal , Eljebri Said , Sabiri Maryame , Zair Touriya 
Published: April 2024

AbstractIn the context of investigations into molecules of natural origin with biological activities. This study focuses on the development of Myrtus communis L., a medicinal plant found in the mountains of Morocco. The first, an analysis carried out on leaves using the inductively coupled plasma spectrometry technique, showed the almost total absence of heavy metals. Furthermore, we aim to identify the chemical composition of its essential oils by gas chromatography‐mass spectrometry (GC/MS) analysis and assess its antibacterial efficacy in vitro and in silico. The average yield of essential oils was 0.9 %±0.06, and GC/MS analysis identified 35 constituents, with myrcene (27,38 %), limonene (16,51 %), α‐pinene (7,32 %) being the major compounds. Remarkably, the essential oils displayed considerable antibacterial activity against various tested bacteria, including Escherichia coli (0.7 μL/mL), Escherichia pseudocoloides (2.8 μl/ml), Escherichia vekanda (2.8 μl/ml). Molecular docking has contributed to our understanding of the mechanism of antibacterial action of the main compounds in this essential oil.
Challenges in Measuring Transport Parameters of Carbonate‐Based Electrolytes
Authors: Lehnert Lukas , Nojabaee Maryam , Latz Arnulf , Horstmann Birger 
Published: April 2024

AbstractNumerical simulations are a powerful tool for the development and improvement of Li‐ion batteries. Modeling the mass transport of the involved electrolytic solutions requires precise determination of the corresponding electrolyte parameters. In this work, we attempt to measure the conductivity, the diffusion coefficient, the transference number and the thermodynamic factor for a system of 0.5 M LiPF6 dissolved in a blend of ethylene carbonate and ethyl methyl carbonate (EC : EMC, 3 : 7 weight) at 20 °C and 50 °C. Applying galvanostatic polarization experiments to symmetrical Li metal | electrolyte+separator | Li metal cells reveals, however, a potential response qualitatively deviating from theoretical expectations. Impeded diffusion processes indicate the presence of additional, undesired porous structures on the Li electrodes, preventing a reliable evaluation of the electrolyte parameters. To spectrally resolve the diffusive processes, we conduct very‐low‐frequency impedance spectroscopy. The impedance in fact exhibits multiple interfering diffusive features. In our measurements, an explicit identification of the impedance for the sole diffusion through the separator is however not feasible. Therefore, the authors doubt that polarizing experiments using Li metal electrodes yield accurate parameters for electrolytes.
Defect Engineering in Bi‐Based Photo/Electrocatalysts for Nitrogen Reduction to Ammonia
Authors: Lv Shuhua , Wang Ying , Wang Debao , Song Caixia 
Published: April 2024

AbstractMain group Bi‐based materials have gained popularity as N2 reduction reaction (NRR) photo/electrocatalysts due to their ability to inhibit competitive H2 evolution reactions (HER) and the unique N2 adsorption activities. The introduction of defects in Bi‐based catalysts represents a highly effective strategy for enhancing light absorption, promoting efficient separation of photogenerated carriers, optimizing the activity of free radicals, regulating electronic structure, and improving catalytic performance. In this review, we outline the various applications of state of the defect engineering in Bi‐based catalysts and elucidate the impact of vacancies on NRR performance. In particular, the types of defects, methods of defects tailoring, advanced characterization techniques, as well as the Bi‐based catalysts with abundant defects and their corresponding catalytic behavior in NRR were elucidated in detail. Finally, the main challenges and opportunities for future development of defective Bi‐based NRR catalysts are discussed, which provides a comprehensive theoretical guidance for this field.
Tartaric Acid Cross‐Linking Polyvinyl Alcohol as Degradable Separators for Rechargeable Lithium Ion Batteries
Authors: Yuan Huimin , Liu Kun , Luo Wen , Wang Zhiqiang , Yan Chunliu , Hu Jing , Wang Xinyang , Liu Guiyu , Xu Zhenghe , Lu Zhouguang 
Published: April 2024

AbstractThe escalating focus on environmental concerns and the swift advancement of eco‐friendly biodegradable batteries raises a pressing demand for enhanced material design in the battery field. The traditional polypropylene (PP) that is monopolistically utilized in the commercial LIBs is hard to recycle. In this work, we prepare a novel water degradable separators via the cross‐linking of polyvinyl alcohol (PVA) and dibasic acid (tartaric acid, TA). Through the integration of non‐solvent liquid‐phase separation, we successfully produced a thermally stable PVA‐TA membrane with tunable thickness and a high level of porosity. These specially engineered PVA‐TA separators were implemented in LiFePO4 (LFP)|separator|Li cells, resulting in superior multiplicative performance and achieving a capacity of 88 mAh g−1 under 5 C. Additionally, the straightforward small molecule cross‐linking technique significantly reduced the crystalline region of the polymer, thereby enhancing ionic conductivity. Notably, after cycling, the PVA‐TA separators can be easily dissolved in 95 °C hot water, enabling its reutilization for the production of new PVA‐TA separators. Therefore, this work introduces a novel concept to design green and sustainable separators for recyclable lithium batteries.
Enhancing Electrochemical Performance of Aluminum‐Ion Batteries with Fluorinated Graphene Cathode
Authors: Lei Haiping , Wei Tianwei , Tu Jiguo , Li Suqin , Jiao Shuqiang 
Published: April 2024

AbstractIn pursuit of high‐performance aluminum‐ion batteries, the selection of a suitable positive electrode material assumes paramount importance, and fluorinated graphene (FG) nanostructures have emerged as an exceptional candidate. In the scope of this study, a flexible tantalum foil is coated with FG to serve as the positive electrode for aluminum‐ion batteries. FG positive electrode demonstrates a remarkable discharge capacity of 109 mA h g−1 at a current density of 200 mA g−1, underscoring its tremendous potential for energy storage applications. Concurrently, the FG positive electrode exhibits a discharge capacity of 101 mA h g−1 while maintaining an impressive coulombic efficiency of 95 % over 300 cycles at a current density of 200 mA g−1, which benefiting from the significant structure of FG. The results of the in‐situ Raman spectroscopy signified the presence of intercalation/de‐intercalation processes of AlCl4− behavior within the FG layers.