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Evaluation of formation susceptibility and sand production potential in an offshore field,Niger Delta Basin,Nigeria

Energy Geoscience 2024年第1期5卷 1-11页

作者： David O.Ubuara Yinka A.Olayinka Godwin O.Emujakporue geoffrey c.soronnadi-ononiwu Department of Geology University of Port HarcourtNigeria Mease Energy Nigeria Limited Port HarcourtNigeria Department of Geology University of IbadanNigeria Department of Physics University of Port HarcourtNigeria

Wellbore instability and sand production are all common challenges in the Niger Delta oil province,resulting in high drilling and production cost as well as damage to oil *** vulnerability of lithologic formations to wellbore instability and resultant sand production is investigated in the four delineated reservoirs of the“Areo”field,western part of Niger Delta *** foundation for establishing the geomechanical properties in this study was a 1-dimensional mechanical earth model,using gamma ray(GR),density(RHOB),compressional slowness(DTc),and shear slowness(DTS)*** the Areo oil field,two wells(well 001 and well 002)were *** evaluated formations are still primarily composed of compacted shale and unconsolidated sandstone,with reservoir sand units exhibiting lower elastic and rock strength properties than shale *** compressibility and porosity make sand more brittle,while low compressibility and porosity make shale stiffer due to high *** maximum force that can be applied to a shale unit without causing it to fail is 17.23 MPa,which is the maximum average rock strength of the *** means that shale requires more vertical stress or pressure than sand does in order to deform it(15.06 MPa).The three sand prediction approaches used in the analysis of sand production predictions have cut-off values that are higher than the average values of the *** Schlumberger sand production index method(S/I)indicates that the reservoir has potential for sand influx in the two wells,with the average of the four reservoirs studied in wells 001 and 002 being 1.551012 psi and 1.141012 psi ***,when a formation's sand production index is less than 1.241012 psi,as it is in this study,the formation is likely to produce *** findings support the notion that the defined sandstone units are highly unconsolidated and have a high potential for producing sands;therefore,sand control techniques must be factored in

关键词： Wireline log Stress Geo-mechanicanical characterization Sand prediction Niger delta

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Deep learning for joint channel estimation and feedback in massive MIMO systems

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Digital communications and Networks 2024年第1期10卷 83-93页

作者： Jiajia Guo Tong chen Shi Jin geoffrey Ye Li Xin Wang Xiaolin Hou National Mobile communications Research Laboratory Southeast UniversityNanjing210096China Department of Electrical and Electronic Engineering Imperial College LondonLondonSW72AZUK DOcOMO Beijing communications Laboratories co. LtdBeijingChina

The great potentials of massive Multiple-Input Multiple-Output(MIMO)in Frequency Division Duplex(FDD)mode can be fully exploited when the downlink channel State Information(cSI)is available at base ***,the accurate csI is difficult to obtain due to the large amount of feedback overhead caused by massive *** this paper,we propose a deep learning based joint channel estimation and feedback framework,which comprehensively realizes the estimation,compression,and reconstruction of downlink channels in FDD massive MIMO *** networks are constructed to perform estimation and feedback explicitly and *** explicit network adopts a multi-Signal-to-Noise-Ratios(SNRs)technique to obtain a single trained channel estimation subnet that works well with different SNRs and employs a deep residual network to reconstruct the channels,while the implicit network directly compresses pilots and sends them back to reduce network *** module is also designed to generate data-bearing *** results show that the two proposed networks exhibit excellent performance of reconstruction and are robust to different environments and quantization errors.

关键词： channel estimation cSI feedback Deep learning Massive MIMO FDD

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Effects of soil metal(loid)s pollution on microbial activities and environmental risks in an abandoned chemical smelting site

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Journal of Environmental Sciences 2024年第9期143卷 60-70页

作者： Hao Li Jun Yao Jianli Liu Ning Min geoffrey Sunahara Dongyang Men Robert Duran School of Water Resources and Environment Research Center of Environmental Science and EngineeringChina University of Geosciences(Beijing)Beijing 100083China Department of Natural Resource Sciences McGill University21111Lakeshore DriveSte-Anne-de-BellevueQuebecH9X 3V9Canada Equipe Environnement et Microbiologie MELODY groupUniversitéde Pau et des Pays de l’AdourE2S-UPPAIPREM UMR CNRS 5254BP 115564013 Pau CedexFrance

Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological *** samples were collected from different depths(0 to 13 m)and analyzed for metal(loid)s content and fractionation,as well as microbial *** potential ecological risk indices for the different soil depths(ordered from high to low)were:1 m(D-1)>surface(S-0)>5 m(D-5)>13 m(D-13)>9 m(D-9),ranging between 1840.65-13,089.62,and representing extremely high environmental risks,of which cd(and probably not arsenic)contributed to the highest environmental risk.A modified combined pollution risk index(McR)combining total content and mobile proportion of metal(loid)s,and relative toxicities,was used to evaluate the degree of contamination and potential environmental *** the near-surface samples(S-0 and D-1 layers),the McR considered that As,cd,Pb,Sb,and Zn achieved high and alarming degrees of contamination,whereas Fe,Mn,and Ti were negligible or low to moderate pollution *** microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity *** analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics(pcrobial metabolic activity in the D-1 layer was low presumably due to heavy metal *** activity indicators and microcalorimetric growth rate(k)measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites.

关键词： Abandoned chemical smelting sites Microbial activities Modified combined pollution risk Microcalorimetry Enzymatic activities

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chalcogenide Ovonic Threshold Switching Selector

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Nano-Micro Letters 2024年第5期16卷 1-40页

作者： Zihao Zhao Sergiu clima Daniele Garbin Robin Degraeve geoffrey Pourtois Zhitang Song Min Zhu National Key Laboratory of Materials for Integrated circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050People’s Republic of China University of chinese Academy of Sciences Beijing 100029People’s Republic of China IMEc Kapedreef 75LeuvenBelgium

Today’s explosion of data urgently requires memory technologies capable of storing large volumes of data in shorter time frames,a feat unattain-able with Flash or *** Optane,commonly referred to as three-dimensional phase change memory,stands out as one of the most promising *** Optane with cross-point architecture is constructed through layering a storage element and a selector known as the ovonic threshold switch(OTS).The OTS device,which employs chalcogenide film,has thereby gathered increased attention in recent *** this paper,we begin by providing a brief introduction to the discovery process of the OTS ***,we summarize the key elec-trical parameters of OTS devices and delve into recent explorations of OTS materials,which are categorized as Se-based,Te-based,and S-based material ***,we discuss various models for the OTS switching mechanism,including field-induced nucleation model,as well as several carrier injection ***,we review the progress and innovations in OTS mechanism ***,we highlight the successful application of OTS devices in three-dimensional high-density memory and offer insights into their promising performance and extensive prospects in emerging applications,such as self-selecting memory and neuromorphic computing.

关键词： Non-volatile memory Ovonic threshold switch(OTS) chalcogenide Selector

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A core-satellite self-assembled SERS aptasensor containing a“biological-silent region”Raman tag for the accurate and ultrasensitive detection of histamine

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Food Science and Human Wellness 2024年第2期13卷 1029-1039页

作者： chen chen Yingfang Zhang Ximo Wang Xuguang Qiao geoffrey I.N.Waterhouse Zhixiang Xu Key Laboratory of Food Processing Technology and Quality control in Shandong Province College of Food Science and EngineeringShandong Agricultural UniversityTai’an 271018China School of chemical Sciences The University of AucklandAuckland 1142New Zealand

Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe_(3)O_(4)@Au MNPs(as the recognize probe for histamine)and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile(4-MBN)(Ag@4-MBN@Ag-c-DNA)as the SERS signal probe for the indirect detection of *** an applied magnetic field in the absence of histamine,the assembly gave an intense Raman signal at“Raman biological-silent”region due to *** the presence of histamine,the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe_(3)O_(4)@Au MNPs,thus decreasing the SERS *** optimal conditions,an ultra-low limit of detection of 0.65×10^(-3)ng/mL and a linear range 10^(-2)-10^5 ng/mL on the SERS aptasensor were *** histamine content in four food samples were analyzed using the SERS aptasensor,with the results consistent with those determined by high performance liquid *** present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices.

关键词： Surface-enhanced Raman spectroscopy Raman biological-silent region Aptamer Histamine detection Universal SERS-tag

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Deep unfolding based channel estimation for wideband terahertz near-field massive MIMO systems

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Frontiers of Information Technology & Electronic Engineering 2024年第8期25卷 1162-1172页

作者： Jiabao GAO Xiaoming cHEN geoffrey Ye LI college of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027China Department of Electrical and Electronic Engineering Imperial College LondonLondon SW 2BUUK

The combination of terahertz and massive multiple-input multiple-output(MIMO)is promising for meeting the increasing data rate demand of future wireless communication systems thanks to the significant band-width and spatial degrees of ***,unique channel features,such as the near-field beam split effect,make channel estimation particularly challenging in terahertz massive MIMO *** one hand,adopting the conventional angular domain transformation dictionary designed for low-frequency far-feld channels will result in degraded channel sparsity and destroyed sparsity structure in the transformed *** the other hand,most existing compressive sensing based channel estimation algorithms cannot achieve high performance and low complexity *** alleviate these issues,in this study,we first adopt frequency-dependent near-field dictionaries to maintain good channel sparsity and sparsity structure in the transformed domain under the near-field beam split ***,a deep unfolding based wideband terahertz massive MIMO channel estimation algorithm is *** each iteration of the approximate message passing-sparse Bayesian learning algorithm,the optimal update rule is learned by a deep neural network(DNN),whose architecture is customized to effectively exploit the inherent channel ***,a mixed training method based on novel designs of the DNN architecture and the loss function is developed to effectively train data from different system *** results validate the superiority of the proposed algorithm in terms of performance,complexity,and robustness.

关键词： Terahertz Massive MIMO channel estimation Deep learning

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SERS-tag techology in food safety and detection:sensing from the"fingerprint"region to the"biological-silent"region

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Journal of Future Foods 2024年第4期4卷 309-323页

作者： chen chen Ximo Wang Ruiqiang Wang geoffrey LN.Waterhouse Zhixiang Xu college of Food Science and Engineering Shandong Agricutural UniversiyTai'an 271018China Shandong cayon Testing co. LtdJining 272000China School of chemical Sciences The University of AucklandAnckland 1142New Zealand

Surface enhanced Raman spectroscopy(SERS)offers many advantages for the fast and sensitive detection of specific compounds,metal ions or pathogens in foods,motivating to its increasing utilization in food ***-tags,typically constructed using signal enhanced substrate,Raman reporter molecules,a biocompatible protective layer and a specific recognition element,provide a powerful tool for the analysis of food *** article reviews recent progress in the development of SERS-tags for food safety assessment covering SERS-tags with characteristic peaks in the“fingerprint”region(800-1800 cm-1)and the“biological-silent”region(1800-2800 cm-1).Following a brief description of SERS substrates,the design,synthesis and applications of SERS-tag are explored in *** application of SERS-tags technology for the detection of microorganisms,pesticides and antibiotics are then ***,the prospects of using SERS-tag in real-world food safety analysis are critically discussed.

关键词： Surface enhanced Raman spectroscopy SERS-tags Raman reporter molecule Fingerprint region Biological-silent region Food Safety

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catatonia:A deep dive into its unfathomable depths

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World Journal of Psychiatry 2024年第2期14卷 210-214页

作者： Peter Phiri Gayathri Delanerolle Oliver Hope Tharangini Murugaiyan geoffrey Dimba Shanaya Rathod Zukiswa Zingela Research&Innovation Department Southern Health NHS Foundation TrustSouthampton SO303JBUnited Kingdom School of Psychology Faculty of Environmental and Life SciencesUniversity of SouthamptonSouthampton SO171BJHampshireUnited Kingdom Acute Inpatients Services Southern Health NHS Foundation TrustBasingstoke RG249RHUnited Kingdom Home Treatment Team South WestSurrey and Borders Partnerships NHS Foundation TrustGuildford GU27XLSurreyUnited Kingdom Faculty of Health Sciences Nelson Mandela UniversitySummerstrand 6001GqeberhaSouth Africa

This editorial addresses catatonia,a complex neuropsychiatric syndrome characterised by a spectrum of psychomotor *** editorial seeks to clarify the ambiguous aspects of catatonia,integrating recent research findings,including global studies and diagnostic *** discusses catatonia’s clinical manifestations,prevalence,and associated psychiatric and medical conditions,with particular emphasis on its frequent co-occurrence with schizophrenia and mood *** prevalence of catatonia,which varies across psychiatric populations,is illustrated by a significant study conducted in Nelson Mandela Bay,South *** study provides valuable insights into the effectiveness of the Bush-Francis Screening Instrument compared to the Diagnostic and Statistical Manual 5 criteria in diagnosing *** editorial evaluates treatment approaches,primarily focusing on benzodiazepines and electroconvulsive therapy,and discusses emerging therapeutic *** underscores the importance of robust diagnostic frameworks and early intervention in managing catatonia,as recommended by the latest evidence-based consensus ***,it suggests future research directions,particularly in exploring the neurobiological and genetic factors of catatonia,to enhance our understanding and improve treatment *** editorial succinctly aims to demystify catatonia and provide valuable insights for clinicians and researchers in mental health care.

关键词： catatonia Schizophrenia Neuropsychiatry Benzodiazepines Electroconvulsive therapy Bush-Francis screening instrument Diagnosis

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Optimization of Methylene Blue Dye Adsorption onto coconut Husk cellulose Using Response Surface Methodology: Adsorption Kinetics, Isotherms and Reusability Studies

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Journal of Materials Science and chemical Engineering 2024年第2期12卷 1-18页

作者： Frank Ouru Omwoyo geoffrey Otieno School of chemistry and Material Science Technical University of Kenya Nairobi Kenya

In this study, coconut husk cellulose was employed as a cost-effective and environmentally friendly adsorbent to eliminate methylene blue (MB) dye from aqueous solutions. The successful development of response surface methodology paired with a central composite design (RSM-ccD) enabled the optimization and modelling of the adsorption process. The study investigated the individual and combined effects of three variables (pH, contact time, and initial MB dye concentration) on the adsorption of MB dye onto coconut husk cellulose. The developed RSM-ccD model exhibited a remarkable degree of precision in predicting the removal efficiency of MB dye within the specified experimental parameters. This was demonstrated by the strong regression parameters, with an R2 value of 99.79% and an adjusted R2 value of 99.6%. The study depicted that the optimal parameters for attaining a 98.8827% removal of MB dye using coconut husk cellulose were as follows: an initial MB dye concentration of 30 mg∙L−1, contact time of 120 minutes, and pH 7 at a fixed adsorbent dose of 0.5 g. The Freundlich isotherm model provided the most satisfactory description of the equilibrium adsorption isotherms, suggesting that MB dye adsorption onto coconut husk cellulose occurs on a heterogeneous surface. The experimental results demonstrated a strong agreement with the pseudo-second-order kinetics model, indicating that the number of active sites present on the cellulose adsorbent predominantly influences the adsorption process of MB dye. Additionally, the adsorbent made from coconut husk cellulose exhibited the potential to be reused, as it retained its efficiency for a maximum of three cycles of adsorption of MB dye. The results of this study show that coconut husk cellulose has the potential to be an effective and sustainable adsorbent for removing MB dye from aqueous solutions.

关键词： Adsorption Kinetics Isotherms Optimization Response Surface Methodology cellulose

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The Impact of the Energy Transition and Sustainable Development Goals on Mineral Resource Availability in Africa

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Smart Grid and Renewable Energy 2024年第7期15卷 149-185页

作者： Benjamin Kolie Ayman Elshkaki geoffrey Sunahara Institute of Geographic Sciences and Natural Resources Research Chinese Academic of Science Beijing China University of the chinese Academy of Sciences Beijing China Key Laboratory of carrying capacity Assessment for Resource and Environment Ministry of Land and Resources Beijing China Department of Natural Resource Sciences McGill University Macdonald Campus Ste-Anne-de-Bellevue Canada

Understanding and predicting the impact of the global energy transition and the United Nations Sustainable Development Goals (SDGs) on global mineral demand and African supply is challenging. This study uses a resource nexus approach to investigate and analyze the impact of this transition on energy and water demand and cO2 emissions using three annual material demand scenarios. The results indicate that African mining will consume more energy by 2050, leading to an increase in cumulative demand for energy (from 98 to 14,577 TWh) and water (from 15,013 to 223,000 million m3), as well as cO2 emissions (1318 and 19,561 Gg cO2e). In contrast, only a modest increase in energy demand (207 TWh) will be required by 2050 to achieve the SDGs. Therefore, the African mining industry should reduce its energy consumption and invest more in the renewable energy sector to support the global energy transition.

关键词： Mineral-Energy Nexus climate change SDGs African Mining Industries Energy Transition

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