Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates...Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.展开更多
This study presents a thorough and holistic review of various studies focusing on the structural analysis of Oil and Gas(O&G)pipelines,with an emphasis on various defect modes.The study appraised pipeline-related ...This study presents a thorough and holistic review of various studies focusing on the structural analysis of Oil and Gas(O&G)pipelines,with an emphasis on various defect modes.The study appraised pipeline-related articles from the empirical,semi-empirical,analytical,and numerical studies.However,the study’s core objective remains to address the persistent challenge that often leads to Burst Pressure Loss(BPL)in a pipeline.These mechanical-associated damages,which can result in BPL,may include pipe scratches,dents,or cracks.Therefore,training a large volume of datasets in neural network architectures or the finite element domain is crucial in this context.The study further explores previous research to gain a deeper insight into how many modes of damage enhance loss in Burst Pressure(BP).The study further synthesises significant reasons why pipeline Structural Health Failures(SHFs)occur,as drawn from existing literature.Failure scenarios in pipeline dent,crack,fracture,buckling,fatigue,corrosion,BPL,and Third-Party Damage(TPD)could result from mechanical deformation,ageing,insufficient real-time monitoring,and TPD influences.Many of the assessed articles conclude that the experimental approach and Finite Element Method(FEM)are valid and can accurately validate one another in the analysis and prediction of pipeline failures.However,this study offers valuable and comprehensive resources for pipeline engineers,academic researchers,and industry professionals.Again,the study is crucial for pipeline fabricators,installers,and operators to keep up with maintenance,repairs,and predictions.展开更多
This study investigated the hydrocarbon source rock potential of the Late Cretaceous Mamu and Nkporo formations in the Asaga-Ohafia Axis,Afikpo Basin,southeastern Nigeria,using integrated facies analysis,organic geoch...This study investigated the hydrocarbon source rock potential of the Late Cretaceous Mamu and Nkporo formations in the Asaga-Ohafia Axis,Afikpo Basin,southeastern Nigeria,using integrated facies analysis,organic geochemical and palynofacies data.Five lithofacies were identified:dark grey shale,oolitic limestone,heterolithic mudstone/sandstone,laminated bioturbated sandstone,and calcareous mudstone,indicating estuarine,deltaic,and shallow marine depositional environments.Total organic carbon(TOC) contents range from 1.47 to 2.40 wt%,which reflects moderate to good organic richness.For the Mamu Formation,kerogen composition is dominated by Type Ⅱ/Ⅲ,composed of 30 %-50 %amorphous organic matter(AOM),5 %-10 % liptinite,30 %-50 % vitrinite,and 10 %-20 % inertinite.Spore coloration and Thermal Alteration Index(TAI:3-3+) suggest thermal maturity within the oil window(Ro:0.80 %-1.50 %).In contrast,the Nkporo Formation shows comparable kerogen composition(20 %-45 % AOM,0-20 % liptinite,and 40 %-65 % vitrinite) but lower maturity(TAI:2-2+;Ro:0.45 %-0.80 %).Rock-Eval pyrolysis further supports these findings.The Mamu Formation displays higher Hydrogen Index,favorable Tmax,and Production Index values,confirming its maturity and oil and gas-prone potential.Palynological assemblages,including marine dinoflagellate cysts(Mamu Formation) and freshwater algae/fungal spores(Nkporo Formation),align with the inferred depositional settings.Thus,the Mamu Formation is the more prolific source rock,characterized by superior organic quality and thermal maturity.展开更多
In-utero exposure to Zika virus(ZIKV)could lead to miscarriage,preterm birth and congenital Zika syndrome.This study aimed at estimating the burden of ZIKV and Dengue virus(DENV)infections among pregnant women in Boju...In-utero exposure to Zika virus(ZIKV)could lead to miscarriage,preterm birth and congenital Zika syndrome.This study aimed at estimating the burden of ZIKV and Dengue virus(DENV)infections among pregnant women in Bojude,Nigeria.A total of 200 blood samples were collected from pregnant women between February and April 2022.Using the updated CDC guidelines for the diagnosis of ZIKV infections,including ELISA and microneutralization test(MNT),we found that 16.5%of participants were positive for ZIKV IgM,10%were positive for IgG,and 23%had nAb in their serum.Among the 46 ZIKV nAb-positive women,52.2%and 10.9%were recent and previous ZIKV infections,respectively,while 6.5%had previous DENV infections.Although no recent DENV infection was detected,recent and previous ZIKV/DENV co-infections were 13.0%and 17.4%,respectively.Two participants had recent secondary ZIKV infections,while 39.1%had prolonged lifelong immunity.Recent ZIKV infection rates were significantly higher among sexually active females aged 20–29 years than other age groups,with the highest risk observed in the first trimester of pregnancy.In addition,the grand-multiparous women are at higher risk of ZIKV infections than other categories.Monotypic recent,secondary and past ZIKV infections,as well as DENV and ZIKV co-infections,were detected in both the asymptomatic and symptomatic pregnant women.These findings highlight that ZIKV infection is prevalent among pregnant women in Nigeria and underscore the associated risk factors,providing evidence-based information on the burden of ZIKV infections in DENV-endemic region.展开更多
Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Bio...Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Biofloc technology(BFT)is self-sustaining and emphasizes nutrient cycling through microbial activity to maintain water quality.The effect of BFT on water quality and profitability of shrimp(Litopenaeus vannamei)culture was determined over a 70-day period.Ponds P1,P2,and P3 were treated with BFT and compared to a control group(P4)without BFT.Bacillus infantis cultured inoculum initiated biofloc development while molasses-maintained C:N ratio of 15:1.One-way ANOVA determined the mean differences in Temperature,pH,dissolved oxygen(DO),total dissolved solid,alkalinity,salinity,ammonia(NH_(3)),nitrates,nitrites(NO_(2)^(-)),calcium,magnesium,as well as shrimp body weight(BW)and total length(TL)across treatments.Profitability was determined by comparing the cost of production with sales and plotting it on a bar chart.BFT shrimp exhibited significantly higher BW(13.6 g)compared to 8.1 g in the control,and maintained a higher survival rate(80–90%)by day 70.Water quality was better managed in BFT,with NH_(3) consistently kept below 0.5mg/L;transient peaks of NO_(2)^(-),more stable pH(averaging at 7.5),and better DO management,maintained above 5 mg/L.BFT provided higher profitability of Ringgit Malaysia(RM)11,019.67(P1)and RM 8651.83(P2)compared to financiallosses in the non-biofloc system.Although operational challenges were reported,BFT showed superior resilience,suggesting that proper technical training and farm management are crucial for its optimization.展开更多
Gas chromatography-mass spectrometry(GC-MS)was used to analyze the pentacyclic triterpenoid distributions,specifically hopane and oleanane fingerprints,in 24 crude oil samples from the Niger Delta depobelts,with the a...Gas chromatography-mass spectrometry(GC-MS)was used to analyze the pentacyclic triterpenoid distributions,specifically hopane and oleanane fingerprints,in 24 crude oil samples from the Niger Delta depobelts,with the aim of defining the petroleum system,filling history,and the age of source rock producing these oils.The results indicate that the Niger Delta oils belong to a single fluvio-deltaic petroleum system,reflecting similar source organic facies and depositional environments.Geochemical parameters,including C29/C30hopane ratios,oleanane index,Ts/Tm,(Ts/(Ts+Tm)),moretane/C30hopane ratios,and C3222S/(22S+22R)ratios,suggest oxic conditions during source rock deposition and thermal maturity of the oils.The presence of terrigenous organic matter and complex filling history are also evident and influenced by multiple phases of sedimentation,and petroleum generation.A comparative plot of geologic time(Paleogene-Neogene age)and oleanane percentage composition show that the crude oils are constrained to the chronostratigraphic ages of their respective depobelts,demonstrating the potential of oleanane-derived parameters for relative dating of hydrocarbon sources,complementing traditional index fossil methods.展开更多
The global discussion surrounding Functionally Graded Materials(FGMs)highlights their unique and diverse micro-material properties that result from varying two or more materials in a strategic combination profile.Thes...The global discussion surrounding Functionally Graded Materials(FGMs)highlights their unique and diverse micro-material properties that result from varying two or more materials in a strategic combination profile.These combinations produce distinct physical and chemical characteristics.Changes in these characteristics may occur continuously,referred to as a gradient function,or discontinuously as a stepwise function.The changes can appear within homogeneous or heterogeneous material geometries.The variation in material properties depends on the volume fraction index function.This variation can occur in 1D,2D,or 3D,either in the thickness or length direction within a material model.The vacuum in the review study on mechanically toughened and thermally resistant Functionally Graded(FG)pipelines prompted the current review study.This study addresses the absence of an appropriate variational function for FG cylindrical pipelines.It proposes a gradation function pattern to improve pipeline structural performance.An appraisal based on relevant FGM literature was conducted to improve the temperature differentials in traditional composite materials and stress-related issues in carbon steel pipelines.The review identifies specific FGM property variations that reduce failures that are possible in conventional materials.Reviewed articles and evaluation procedures followed the 2020 PRISMA guidelines.Literature was obtained from Scopus,Connected Papers,and other reputable sources.The study also discusses potential FG pipelines for gas and green energy transportation.The reviewed literature establishes the context for this research and addresses the gap in 3D FG model variation functions involving multiple materials.展开更多
A field trial to evaluate the growth and nutrient uptake of cocoa intercropped with coconut was conducted in Cocoa Research Institute of Nigeria(CRIN)Headquarters,Idi-Ayunre,Ibadan,Oyo State between 2019 and 2022.Ther...A field trial to evaluate the growth and nutrient uptake of cocoa intercropped with coconut was conducted in Cocoa Research Institute of Nigeria(CRIN)Headquarters,Idi-Ayunre,Ibadan,Oyo State between 2019 and 2022.There were four treatments comprising of cocoa sole,cocoa/plantain,cocoa/coconut and cocoa/coconut/plantain intercrop.The experimental design was Randomized Complete Block(RCB)replicated three times.Result obtained showed that cocoa/plantain was significantly higher(p<0.05)than all other treatments in all parameters considered and closely followed by cocoa/coconut,then cocoa sole with cocoa/plantain/coconut giving the least performance.The same trend was observed in the nutrient uptake.It was also observed in the trial that the two crops:cocoa and coconut did not show any deleterious effect on their growth when intercropped together.This showed that the two crops are compatible when grown on the same piece of land.Therefore,cocoa/coconut intercrop could be recommended to cocoa farmers in south west Nigeria to increase their revenue generation when coconut starts bearing fruit instead of sole planting of cocoa.展开更多
This study evaluates the Fuzzy Analytical Hierarchy Process(FAHP)as a multi-criteria decision(MCD)support tool for selecting appropriate additive manufacturing(AM)techniques that align with cleaner production and envi...This study evaluates the Fuzzy Analytical Hierarchy Process(FAHP)as a multi-criteria decision(MCD)support tool for selecting appropriate additive manufacturing(AM)techniques that align with cleaner production and environmental sustainability.The FAHP model was validated using an example of the production of aircraft components(specifically fuselage)employing AM technologies such as Wire Arc Additive Manufacturing(WAAM),laser powder bed fusion(L-PBF),Binder Jetting(BJ),Selective Laser Sintering(SLS),and Laser Metal Deposition(LMD).The selection criteria prioritized eco-friendly manufacturing considerations,including the quality and properties of the final product(e.g.,surface finish,high strength,and corrosion resistance),service and functional requirements,weight reduction for improved energy efficiency(lightweight structures),and environmental responsibility.Sustainability metrics,such as cost-effectiveness,material efficiency,waste minimization,and environmental impact,are central to the evaluation process.A computer-aided modeling approach was also used to simulate the performance of aluminum(AA7075 T6),steel(304),and titanium alloy(Ti6Al4V)for fuselage development.The results demonstrate that MCD approaches such as FAHP can effectively guide the selection of AM technologies that meet functional and technical requirements while minimizing environmental degradation footprints.Furthermore,the aluminumalloy outperformed the other materials investigated in the simulation with the lowest stress concentration and least deformation.This study contributes to advancing cleaner production practices by providing a decision-making framework for sustainable and eco-friendly manufacturing,enabling manufacturers to adopt AM technologies that promote environmental responsibility and sustainable development,while maintaining product quality and performance.展开更多
In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to ...In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to solve this problem,the microstructure and electrochemical corrosion properties of Al-8Si-3Fe-xIn alloy under low chlorine conditions were studied.The results show that indium(In)dissolves to form In^(3+)and In^(+)reverse plating on the surface of the bare substrate to form a passivation film defect.When the In content is high,the segregated In forms an activation point in the form of a cathode phase.In activatesτ_(6)phase to form a micro-couple,which improves the non-uniform corrosion.The In-containing corrosion products at the phase boundary hinder the diffusion of Cl−.With an increase of In content,the self-corrosion potential(Ecorr)of the alloy shifts negatively,and the self-corrosion current density(Jcorr)decreases from 6.477μA/cm^(2)to 1.352μA/cm^(2),and then increases gradually.However,when the In content is 0.1%,the Ecorr of the alloy changes from−0.824 V to−0.932 V,and the Jcorr decreases from 6.477μA/cm^(2)to 4.699μA/cm^(2),suggesting that the use of sacrificial anode will give the best effect.展开更多
This study integrates gravity and aeromagnetic datasets to delineate basement depth and characterise the subsurface structural framework of the Gerad Graben in the western Sirt Basin,Libya.Techniques including high-pa...This study integrates gravity and aeromagnetic datasets to delineate basement depth and characterise the subsurface structural framework of the Gerad Graben in the western Sirt Basin,Libya.Techniques including high-pass filtering,Centre for Exploration Targeting(CET) edge detection,Source Parameter Imaging(SPI),and Euler Deconvolution(ED) were applied to residual gravity and residual reduced-topole(RTP) magnetic data to enhance fault mapping and basement morphology.Tests of various cutoff wavelengths show that 10 km for gravity and 15 km for magnetic data provide optimal resolution of shallow structures while preserving deeper trends.Forward 2D GM-SYS modelling and Werner Deconvolution further constrained the geometry and depth of intrusive bodies and fault systems.Results reveal a structurally complex graben with NE-SW,NW-SE,ENE-WSW,and N-S trending faults,indicating multiphase tectonic deformation.Graben-bounding faults show displacement values of600-4290 m,and basement depths in the central depocenter reach 4275-4300 m,validated by well NTF-50.Magnetic anomalies indicate intrusive igneous bodies,including NW-SE-trending sills and dikes,associated with the Tibesti and Al Haruj volcanic provinces.These intrusions likely caused localised heating,uplift,and fault reactivation.The integrated interpretation supports a tectonomagmatic evolution involving successive rifting phases from the Paleozoic to Cenozoic,influenced by inherited Precambrian structures.These features,coupled with substantial sediment infill and magmatic activity,enhance the hydrocarbon potential of the Gerad Graben,suggesting the presence of structural and stratigraphic traps within the broader of Sirt Basin petroleum system.展开更多
This study was conducted to investigate the properties of Pr^(3+)-Dy^(3+)doped Zn_(2)Y-type hexaferrite for potential technological applications.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and ...This study was conducted to investigate the properties of Pr^(3+)-Dy^(3+)doped Zn_(2)Y-type hexaferrite for potential technological applications.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and field-emission scanning electron microscopy(FESEM)were used to analyze structural properties.The crystallite size in the synthesized samples varies between 57.54 and 68.57 nm.The vibrational bands at 400 and 600 cm^(-1),common to all hexaferrites,were confirmed through FTIR.The FESEM analysis reveals an agglomeration of magnetic grains and a decrease in the average grain size from 1.24 to1.06μm.The M-H loops show that,with x values of 0.0,0.1,and 0.2,the saturation magnetization is determined to be 34.76,34.23,and 32.52 emu/g,respectively.The corresponding coercivity values are21.24,30.39,and 33.99 Oe.UV-visible spectroscopy using Tauc theory reveals an increase in the optical band gap from 2.32 to 2.50 eV,indicating a tunable energy band structure by incorporating Pr^(3+)-Dy^(3+)ions.The dielectric constant increases,whereas AC conductivity decreases with increased Pr^(3+)-Dy^(3+)concentration.The obtained results suggest the potential suitability of these materials for various technological applications.展开更多
Antimicrobial resistance(AMR)in Salmonella is a major concern in terms of human health,environmental sustainability,and global food security.Salmonella,the world's most prevalent foodborne pathogen,has gradually g...Antimicrobial resistance(AMR)in Salmonella is a major concern in terms of human health,environmental sustainability,and global food security.Salmonella,the world's most prevalent foodborne pathogen,has gradually gained resistance to important drugs,complicating treatment efforts and leading to rising morbidity,mortality,and economic costs.Overuse of antibiotics in human medicine and agriculture,inadequate regulatory compliance,and environmental pollution from agricultural runoff and treated sewage all contribute to the growth and spread of AMR in Salmonella.Health as well as viewpoints on environmental,animal,and human health will be required to address this complicated problem.This includes promoting reasonable antibiotic use,improving global surveillance systems,and researching novel treatments including phage therapy,probiotics,and new antibiotics.Proposals for vaccination and precise food safety standards are critical for limiting Salmonella transmission across the food chain.Despite significant progress,critical research gaps continue,specifically in understanding the molecular basis of resistance and the role of environmental practices.However,contemporary research endeavors are concentrated on identifying and comprehending the prevalence of extensively drug-resistant Salmonella strains,elucidating the bacterium's defense mechanisms against antibiotics,and investigating outbreaks associated with vegetables.Global surveillance,the development of alternative therapies,and the implementation of stricter antibiotic policies are essential strategies in addressing AMR in Salmonella.Additionally,policy design and implementation,capacity building in low-and middle-income countries,and raising public awareness all necessitate urgent global collaboration among governments,international agencies,non-governmental organizations,and the corporate sector.Stricter regulations on overuse of antibiotics in agriculture is also called for.This review highlights the importance of multi-disciplinary struggles in engaging Salmonella,as integrated resolutions through a One Health approach are crucial for ensuring food safety,preserving public health,and minimizing the worldwide threat of AMR.展开更多
The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon,which constitutes a portion of the Yola Arm of the Upper Benue Trough.This study presents the first comprehensive dataset combining mineral-...The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon,which constitutes a portion of the Yola Arm of the Upper Benue Trough.This study presents the first comprehensive dataset combining mineral-ogical,bulk-rock geochemical,and stable C-H-O isotopic data for dark-gray,finegrained mudstones from the basin,providing new insights into its sediment source,paleoenvironment,and geodynamic setting.The mudstones primarily consist of phyllosilicates(~8.6%),feldspars(~30.5%),carbonates(~13.7%),and minor iron oxides(~2.7%),with vermiculite,illite,and kaolinite as the main clay minerals.The presence of analcime,ankerite,and dolomite suggests low-grade metamorphism and/or hydrothermal alteration.Fe_(2)O_(3)/K_(2)O(1.52-6.40)and SiO_(2)/Al_(2)O_(3)(2.97-4.68)ratios classify the mudstones as compositionally immature shales(ICV~1.64)with low-moderate chemical weathering(CIA~56.35;PIA~59.74;R^(3+)/R^(3+)+R^(2+)+M^(+)~0.51).Trace element ratios(Th/Sc~1.70,Zr/Sc~1.33,La/Sc~6.30,La/Th~4.14)indicate an intermediate igneous provenance from a continental crustal source.Paleoenviron-mental proxies suggest deposition in a dynamic basin environment marked by fluctuating redox(C org/P:0.21-178.34)and salinity(Sr/Ba:0.34-3.25;N-values:48-35.92)conditions,ranging from oxic to anoxic and brackish to saline.Major element data(SiO_(2) vs.Al_(2)O_(3)+K_(2)O+Na_(2)O)indicate a semi-arid regime,while Paleoclimatic indicators such as Sr/Cu(1.88-37.47)and C-values(0.12-0.93)suggests alter-nating humid and arid conditions.Notably,stable isotope data,reported here for the first time in the Koum Basin,reveal a predominantly terrestrial,fluvial-deltaic C_(3) plant source for organic carbon(δ^(13)C-25.2‰ to -35.2‰)and complex fluid-rock interactions involving meteoric and magmatic-metamorphic fluids under a warm,equatorial climate(δ^(18)O+3.6‰to +24.9‰,δ^(2)H-104‰ to-50‰).The combined mineralogical,geochemical,and isotopic data point to deposition in a tectonically active continental arc setting,with contributions from ocean island arc and passive margin sources.展开更多
The advent of civilization has made humans dependent on plants for food and medicine,leading to the intensification of agricultural production.The intense cultivation of crops has resulted in the depletion of availabl...The advent of civilization has made humans dependent on plants for food and medicine,leading to the intensification of agricultural production.The intense cultivation of crops has resulted in the depletion of available nutrients from soil,thereby demanding the application of excess nutrients to soil to improve yield.Thus,mineral fertilizer discovery and application have,in many ways,contributed greatly to meeting global food demands.However,aside from the positive effects of mineral fertilizers,their excessive application to soil produces large amounts of pollutants that affect environmental sustainability.This necessitates the study of the major mineral fertilizer elements(nitrogen(N),phosphorus(P),and potassium(K)),the forms in which they are applied to soil,and their chemistry/reactions in soil.Here,we reviewed the forms of different N,P,and K mineral fertilizers to provide current knowledge on their constituents,the chemistry of N,P,and K in soil to understand the reactions they undertake in soil,the efficient methods of fertilizer application for environmental sustainability,the effects of mineral fertilizer loss to the environment,and improved fertilization technologies for environmental sustainability.Nanofertilizers are a promising technology for sustainable agricultural production and are discussed in detail in this review.展开更多
The Cretaceous Mamu Formation coal samples located within the Northern Anambra Basin were collected, analysed and interpreted using multivariate statistical approach to determine the major, trace and rare elements ass...The Cretaceous Mamu Formation coal samples located within the Northern Anambra Basin were collected, analysed and interpreted using multivariate statistical approach to determine the major, trace and rare elements association with a view to determine the source of the terrestrial rocks, palaeoweathering/climatic conditions and tectonic setting. The dominant oxides such as SiO2, A12O3, Fe2O3, TiO2 and CaO were identified in the coal to suggest terrigenous origin. The ratio of SiO2/Al2O3 of 4.8 suggests that the coal was formed from low land peat associated with freshwater continental marine or blackish water with low salinity as indicated by Sr/Ba and CaO + MgO/K2O + Na2。ratios. The major oxides also revealed stable condition of deposition, low degree of tectonic setting but constant subsidence in the basin. The condition of deposition was acidic in nature as indicated by TiO2/Zr plot. Based on the abundance of Zr, Zn, Ba, Ni, Co, Sr, V, and Y, moderate salinity, sub-oxic to oxic bottom water condition was prevalent and also indication of marine influence. Based on the ratios of La/Yb;La/Sm and Gd/Yb, LREE has higher enrichment than HREE. Humid climatic conditions were observed at the coal formation stage while weak laterization to kaolinization was also evidence.展开更多
The positive ecological interaction between gap formation and natural regeneration has been examined but little research has been carried out on the effects of gaps on natural regeneration in forests under different i...The positive ecological interaction between gap formation and natural regeneration has been examined but little research has been carried out on the effects of gaps on natural regeneration in forests under different intensities of disturbance.This study evaluates the composition,diversity,regeneration density and abundance of natural regeneration of tree species in gaps in undisturbed,intermittently disturbed,and disturbed forest sites.Bia Tano Forest Reserve in Ghana was the study area and three gaps each were selected in the three forest site categories.Ten circular subsampling areas of 1 m2 were delineated at 2 m spacing along north,south,east,and west transects within individual gaps.Data on natural regeneration<350 cm height were gathered.The results show that the intensity of disturbance was disproportional to gap size.Species diversity differed significantly between undisturbed and disturbed sites and,also between intermittently disturbed and disturbed sites for Simpson’s(1-D),Equitability(J),and Berger-Parker(B-P)indices.However,there was no significant difference among forest sites for Shannon diversity(H)and Margalef richness(MI)indices.Tree species composition on the sites differed.Regeneration density on the disturbed site was significantly higher than on the two other sites.Greater abundance and density of shade-dependent species on all sites identified them as opportunistic replacements of gap-dependent pioneers.Pioneer species giving way to shade tolerant species is a natural process,thus make them worst variant in gap regeneration.展开更多
For the purpose of overcoming the lack of durability problems associated with superhydrophobic surfaces which hitherto has limited their use;we prepared multi-stimuli wettability response coatings using a mixture of f...For the purpose of overcoming the lack of durability problems associated with superhydrophobic surfaces which hitherto has limited their use;we prepared multi-stimuli wettability response coatings using a mixture of fluorocarbon resin and urea-formaldehyde microcapsules filled with fluorosilane via interfacial polymerization process.The microcapsules are of good thermal stability and can be triggered to release their core content on exposure to atmospheric conditions resulting in the increase in the water contact angle from 97°to 151°.The prepared coatings gave good adhesion strength,and also showed an increase in the hydrophobic property after undergoing scratch,solvent and UV accelerated aging test.In addition,they offered good self-healing of the hydrophobic property after an initial loss due to alkaline immersion and oxygen plasma etching.The electrochemical measurements revealed a remarkable impedance recovery and suppression of corrosion activities,suggesting them to be a potential candidate material for corrosion protection.展开更多
基金supported by the National Natural Science Foundation of China(No.52001034)the China Postdoctoral Science Foundation(No.2023M731677)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_3032).
文摘Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.
文摘This study presents a thorough and holistic review of various studies focusing on the structural analysis of Oil and Gas(O&G)pipelines,with an emphasis on various defect modes.The study appraised pipeline-related articles from the empirical,semi-empirical,analytical,and numerical studies.However,the study’s core objective remains to address the persistent challenge that often leads to Burst Pressure Loss(BPL)in a pipeline.These mechanical-associated damages,which can result in BPL,may include pipe scratches,dents,or cracks.Therefore,training a large volume of datasets in neural network architectures or the finite element domain is crucial in this context.The study further explores previous research to gain a deeper insight into how many modes of damage enhance loss in Burst Pressure(BP).The study further synthesises significant reasons why pipeline Structural Health Failures(SHFs)occur,as drawn from existing literature.Failure scenarios in pipeline dent,crack,fracture,buckling,fatigue,corrosion,BPL,and Third-Party Damage(TPD)could result from mechanical deformation,ageing,insufficient real-time monitoring,and TPD influences.Many of the assessed articles conclude that the experimental approach and Finite Element Method(FEM)are valid and can accurately validate one another in the analysis and prediction of pipeline failures.However,this study offers valuable and comprehensive resources for pipeline engineers,academic researchers,and industry professionals.Again,the study is crucial for pipeline fabricators,installers,and operators to keep up with maintenance,repairs,and predictions.
文摘This study investigated the hydrocarbon source rock potential of the Late Cretaceous Mamu and Nkporo formations in the Asaga-Ohafia Axis,Afikpo Basin,southeastern Nigeria,using integrated facies analysis,organic geochemical and palynofacies data.Five lithofacies were identified:dark grey shale,oolitic limestone,heterolithic mudstone/sandstone,laminated bioturbated sandstone,and calcareous mudstone,indicating estuarine,deltaic,and shallow marine depositional environments.Total organic carbon(TOC) contents range from 1.47 to 2.40 wt%,which reflects moderate to good organic richness.For the Mamu Formation,kerogen composition is dominated by Type Ⅱ/Ⅲ,composed of 30 %-50 %amorphous organic matter(AOM),5 %-10 % liptinite,30 %-50 % vitrinite,and 10 %-20 % inertinite.Spore coloration and Thermal Alteration Index(TAI:3-3+) suggest thermal maturity within the oil window(Ro:0.80 %-1.50 %).In contrast,the Nkporo Formation shows comparable kerogen composition(20 %-45 % AOM,0-20 % liptinite,and 40 %-65 % vitrinite) but lower maturity(TAI:2-2+;Ro:0.45 %-0.80 %).Rock-Eval pyrolysis further supports these findings.The Mamu Formation displays higher Hydrogen Index,favorable Tmax,and Production Index values,confirming its maturity and oil and gas-prone potential.Palynological assemblages,including marine dinoflagellate cysts(Mamu Formation) and freshwater algae/fungal spores(Nkporo Formation),align with the inferred depositional settings.Thus,the Mamu Formation is the more prolific source rock,characterized by superior organic quality and thermal maturity.
文摘In-utero exposure to Zika virus(ZIKV)could lead to miscarriage,preterm birth and congenital Zika syndrome.This study aimed at estimating the burden of ZIKV and Dengue virus(DENV)infections among pregnant women in Bojude,Nigeria.A total of 200 blood samples were collected from pregnant women between February and April 2022.Using the updated CDC guidelines for the diagnosis of ZIKV infections,including ELISA and microneutralization test(MNT),we found that 16.5%of participants were positive for ZIKV IgM,10%were positive for IgG,and 23%had nAb in their serum.Among the 46 ZIKV nAb-positive women,52.2%and 10.9%were recent and previous ZIKV infections,respectively,while 6.5%had previous DENV infections.Although no recent DENV infection was detected,recent and previous ZIKV/DENV co-infections were 13.0%and 17.4%,respectively.Two participants had recent secondary ZIKV infections,while 39.1%had prolonged lifelong immunity.Recent ZIKV infection rates were significantly higher among sexually active females aged 20–29 years than other age groups,with the highest risk observed in the first trimester of pregnancy.In addition,the grand-multiparous women are at higher risk of ZIKV infections than other categories.Monotypic recent,secondary and past ZIKV infections,as well as DENV and ZIKV co-infections,were detected in both the asymptomatic and symptomatic pregnant women.These findings highlight that ZIKV infection is prevalent among pregnant women in Nigeria and underscore the associated risk factors,providing evidence-based information on the burden of ZIKV infections in DENV-endemic region.
基金supported by Ministry of Higher Education,Malaysia through the Translational Research Program entitled Program Traslasional Sektor Makanan Laut Malaysia untuk Kelestarian Pengeluaran Udang Marin dan Penjanaan Pendapatan-Tinggi:Aplikasi Teknologi“Rapid Biofloc”(UMT/PPIJIM/2-2/68/Trans-KPT)grant number[Vot.No:58932].
文摘Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Biofloc technology(BFT)is self-sustaining and emphasizes nutrient cycling through microbial activity to maintain water quality.The effect of BFT on water quality and profitability of shrimp(Litopenaeus vannamei)culture was determined over a 70-day period.Ponds P1,P2,and P3 were treated with BFT and compared to a control group(P4)without BFT.Bacillus infantis cultured inoculum initiated biofloc development while molasses-maintained C:N ratio of 15:1.One-way ANOVA determined the mean differences in Temperature,pH,dissolved oxygen(DO),total dissolved solid,alkalinity,salinity,ammonia(NH_(3)),nitrates,nitrites(NO_(2)^(-)),calcium,magnesium,as well as shrimp body weight(BW)and total length(TL)across treatments.Profitability was determined by comparing the cost of production with sales and plotting it on a bar chart.BFT shrimp exhibited significantly higher BW(13.6 g)compared to 8.1 g in the control,and maintained a higher survival rate(80–90%)by day 70.Water quality was better managed in BFT,with NH_(3) consistently kept below 0.5mg/L;transient peaks of NO_(2)^(-),more stable pH(averaging at 7.5),and better DO management,maintained above 5 mg/L.BFT provided higher profitability of Ringgit Malaysia(RM)11,019.67(P1)and RM 8651.83(P2)compared to financiallosses in the non-biofloc system.Although operational challenges were reported,BFT showed superior resilience,suggesting that proper technical training and farm management are crucial for its optimization.
文摘Gas chromatography-mass spectrometry(GC-MS)was used to analyze the pentacyclic triterpenoid distributions,specifically hopane and oleanane fingerprints,in 24 crude oil samples from the Niger Delta depobelts,with the aim of defining the petroleum system,filling history,and the age of source rock producing these oils.The results indicate that the Niger Delta oils belong to a single fluvio-deltaic petroleum system,reflecting similar source organic facies and depositional environments.Geochemical parameters,including C29/C30hopane ratios,oleanane index,Ts/Tm,(Ts/(Ts+Tm)),moretane/C30hopane ratios,and C3222S/(22S+22R)ratios,suggest oxic conditions during source rock deposition and thermal maturity of the oils.The presence of terrigenous organic matter and complex filling history are also evident and influenced by multiple phases of sedimentation,and petroleum generation.A comparative plot of geologic time(Paleogene-Neogene age)and oleanane percentage composition show that the crude oils are constrained to the chronostratigraphic ages of their respective depobelts,demonstrating the potential of oleanane-derived parameters for relative dating of hydrocarbon sources,complementing traditional index fossil methods.
基金The Petroleum Training Development Fund(PTDF)is highly acknowledged for sponsorship.
文摘The global discussion surrounding Functionally Graded Materials(FGMs)highlights their unique and diverse micro-material properties that result from varying two or more materials in a strategic combination profile.These combinations produce distinct physical and chemical characteristics.Changes in these characteristics may occur continuously,referred to as a gradient function,or discontinuously as a stepwise function.The changes can appear within homogeneous or heterogeneous material geometries.The variation in material properties depends on the volume fraction index function.This variation can occur in 1D,2D,or 3D,either in the thickness or length direction within a material model.The vacuum in the review study on mechanically toughened and thermally resistant Functionally Graded(FG)pipelines prompted the current review study.This study addresses the absence of an appropriate variational function for FG cylindrical pipelines.It proposes a gradation function pattern to improve pipeline structural performance.An appraisal based on relevant FGM literature was conducted to improve the temperature differentials in traditional composite materials and stress-related issues in carbon steel pipelines.The review identifies specific FGM property variations that reduce failures that are possible in conventional materials.Reviewed articles and evaluation procedures followed the 2020 PRISMA guidelines.Literature was obtained from Scopus,Connected Papers,and other reputable sources.The study also discusses potential FG pipelines for gas and green energy transportation.The reviewed literature establishes the context for this research and addresses the gap in 3D FG model variation functions involving multiple materials.
文摘A field trial to evaluate the growth and nutrient uptake of cocoa intercropped with coconut was conducted in Cocoa Research Institute of Nigeria(CRIN)Headquarters,Idi-Ayunre,Ibadan,Oyo State between 2019 and 2022.There were four treatments comprising of cocoa sole,cocoa/plantain,cocoa/coconut and cocoa/coconut/plantain intercrop.The experimental design was Randomized Complete Block(RCB)replicated three times.Result obtained showed that cocoa/plantain was significantly higher(p<0.05)than all other treatments in all parameters considered and closely followed by cocoa/coconut,then cocoa sole with cocoa/plantain/coconut giving the least performance.The same trend was observed in the nutrient uptake.It was also observed in the trial that the two crops:cocoa and coconut did not show any deleterious effect on their growth when intercropped together.This showed that the two crops are compatible when grown on the same piece of land.Therefore,cocoa/coconut intercrop could be recommended to cocoa farmers in south west Nigeria to increase their revenue generation when coconut starts bearing fruit instead of sole planting of cocoa.
文摘This study evaluates the Fuzzy Analytical Hierarchy Process(FAHP)as a multi-criteria decision(MCD)support tool for selecting appropriate additive manufacturing(AM)techniques that align with cleaner production and environmental sustainability.The FAHP model was validated using an example of the production of aircraft components(specifically fuselage)employing AM technologies such as Wire Arc Additive Manufacturing(WAAM),laser powder bed fusion(L-PBF),Binder Jetting(BJ),Selective Laser Sintering(SLS),and Laser Metal Deposition(LMD).The selection criteria prioritized eco-friendly manufacturing considerations,including the quality and properties of the final product(e.g.,surface finish,high strength,and corrosion resistance),service and functional requirements,weight reduction for improved energy efficiency(lightweight structures),and environmental responsibility.Sustainability metrics,such as cost-effectiveness,material efficiency,waste minimization,and environmental impact,are central to the evaluation process.A computer-aided modeling approach was also used to simulate the performance of aluminum(AA7075 T6),steel(304),and titanium alloy(Ti6Al4V)for fuselage development.The results demonstrate that MCD approaches such as FAHP can effectively guide the selection of AM technologies that meet functional and technical requirements while minimizing environmental degradation footprints.Furthermore,the aluminumalloy outperformed the other materials investigated in the simulation with the lowest stress concentration and least deformation.This study contributes to advancing cleaner production practices by providing a decision-making framework for sustainable and eco-friendly manufacturing,enabling manufacturers to adopt AM technologies that promote environmental responsibility and sustainable development,while maintaining product quality and performance.
基金Projects(52171003,52271005)supported by the National Science and Technology Major Project of ChinaProject(KYCX23_3032)supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China。
文摘In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to solve this problem,the microstructure and electrochemical corrosion properties of Al-8Si-3Fe-xIn alloy under low chlorine conditions were studied.The results show that indium(In)dissolves to form In^(3+)and In^(+)reverse plating on the surface of the bare substrate to form a passivation film defect.When the In content is high,the segregated In forms an activation point in the form of a cathode phase.In activatesτ_(6)phase to form a micro-couple,which improves the non-uniform corrosion.The In-containing corrosion products at the phase boundary hinder the diffusion of Cl−.With an increase of In content,the self-corrosion potential(Ecorr)of the alloy shifts negatively,and the self-corrosion current density(Jcorr)decreases from 6.477μA/cm^(2)to 1.352μA/cm^(2),and then increases gradually.However,when the In content is 0.1%,the Ecorr of the alloy changes from−0.824 V to−0.932 V,and the Jcorr decreases from 6.477μA/cm^(2)to 4.699μA/cm^(2),suggesting that the use of sacrificial anode will give the best effect.
文摘This study integrates gravity and aeromagnetic datasets to delineate basement depth and characterise the subsurface structural framework of the Gerad Graben in the western Sirt Basin,Libya.Techniques including high-pass filtering,Centre for Exploration Targeting(CET) edge detection,Source Parameter Imaging(SPI),and Euler Deconvolution(ED) were applied to residual gravity and residual reduced-topole(RTP) magnetic data to enhance fault mapping and basement morphology.Tests of various cutoff wavelengths show that 10 km for gravity and 15 km for magnetic data provide optimal resolution of shallow structures while preserving deeper trends.Forward 2D GM-SYS modelling and Werner Deconvolution further constrained the geometry and depth of intrusive bodies and fault systems.Results reveal a structurally complex graben with NE-SW,NW-SE,ENE-WSW,and N-S trending faults,indicating multiphase tectonic deformation.Graben-bounding faults show displacement values of600-4290 m,and basement depths in the central depocenter reach 4275-4300 m,validated by well NTF-50.Magnetic anomalies indicate intrusive igneous bodies,including NW-SE-trending sills and dikes,associated with the Tibesti and Al Haruj volcanic provinces.These intrusions likely caused localised heating,uplift,and fault reactivation.The integrated interpretation supports a tectonomagmatic evolution involving successive rifting phases from the Paleozoic to Cenozoic,influenced by inherited Precambrian structures.These features,coupled with substantial sediment infill and magmatic activity,enhance the hydrocarbon potential of the Gerad Graben,suggesting the presence of structural and stratigraphic traps within the broader of Sirt Basin petroleum system.
基金the Deanship of Scientific Research at King Khalid University for funding this work through large group Research Project under grant number RGP2/226/44。
文摘This study was conducted to investigate the properties of Pr^(3+)-Dy^(3+)doped Zn_(2)Y-type hexaferrite for potential technological applications.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and field-emission scanning electron microscopy(FESEM)were used to analyze structural properties.The crystallite size in the synthesized samples varies between 57.54 and 68.57 nm.The vibrational bands at 400 and 600 cm^(-1),common to all hexaferrites,were confirmed through FTIR.The FESEM analysis reveals an agglomeration of magnetic grains and a decrease in the average grain size from 1.24 to1.06μm.The M-H loops show that,with x values of 0.0,0.1,and 0.2,the saturation magnetization is determined to be 34.76,34.23,and 32.52 emu/g,respectively.The corresponding coercivity values are21.24,30.39,and 33.99 Oe.UV-visible spectroscopy using Tauc theory reveals an increase in the optical band gap from 2.32 to 2.50 eV,indicating a tunable energy band structure by incorporating Pr^(3+)-Dy^(3+)ions.The dielectric constant increases,whereas AC conductivity decreases with increased Pr^(3+)-Dy^(3+)concentration.The obtained results suggest the potential suitability of these materials for various technological applications.
文摘Antimicrobial resistance(AMR)in Salmonella is a major concern in terms of human health,environmental sustainability,and global food security.Salmonella,the world's most prevalent foodborne pathogen,has gradually gained resistance to important drugs,complicating treatment efforts and leading to rising morbidity,mortality,and economic costs.Overuse of antibiotics in human medicine and agriculture,inadequate regulatory compliance,and environmental pollution from agricultural runoff and treated sewage all contribute to the growth and spread of AMR in Salmonella.Health as well as viewpoints on environmental,animal,and human health will be required to address this complicated problem.This includes promoting reasonable antibiotic use,improving global surveillance systems,and researching novel treatments including phage therapy,probiotics,and new antibiotics.Proposals for vaccination and precise food safety standards are critical for limiting Salmonella transmission across the food chain.Despite significant progress,critical research gaps continue,specifically in understanding the molecular basis of resistance and the role of environmental practices.However,contemporary research endeavors are concentrated on identifying and comprehending the prevalence of extensively drug-resistant Salmonella strains,elucidating the bacterium's defense mechanisms against antibiotics,and investigating outbreaks associated with vegetables.Global surveillance,the development of alternative therapies,and the implementation of stricter antibiotic policies are essential strategies in addressing AMR in Salmonella.Additionally,policy design and implementation,capacity building in low-and middle-income countries,and raising public awareness all necessitate urgent global collaboration among governments,international agencies,non-governmental organizations,and the corporate sector.Stricter regulations on overuse of antibiotics in agriculture is also called for.This review highlights the importance of multi-disciplinary struggles in engaging Salmonella,as integrated resolutions through a One Health approach are crucial for ensuring food safety,preserving public health,and minimizing the worldwide threat of AMR.
文摘The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon,which constitutes a portion of the Yola Arm of the Upper Benue Trough.This study presents the first comprehensive dataset combining mineral-ogical,bulk-rock geochemical,and stable C-H-O isotopic data for dark-gray,finegrained mudstones from the basin,providing new insights into its sediment source,paleoenvironment,and geodynamic setting.The mudstones primarily consist of phyllosilicates(~8.6%),feldspars(~30.5%),carbonates(~13.7%),and minor iron oxides(~2.7%),with vermiculite,illite,and kaolinite as the main clay minerals.The presence of analcime,ankerite,and dolomite suggests low-grade metamorphism and/or hydrothermal alteration.Fe_(2)O_(3)/K_(2)O(1.52-6.40)and SiO_(2)/Al_(2)O_(3)(2.97-4.68)ratios classify the mudstones as compositionally immature shales(ICV~1.64)with low-moderate chemical weathering(CIA~56.35;PIA~59.74;R^(3+)/R^(3+)+R^(2+)+M^(+)~0.51).Trace element ratios(Th/Sc~1.70,Zr/Sc~1.33,La/Sc~6.30,La/Th~4.14)indicate an intermediate igneous provenance from a continental crustal source.Paleoenviron-mental proxies suggest deposition in a dynamic basin environment marked by fluctuating redox(C org/P:0.21-178.34)and salinity(Sr/Ba:0.34-3.25;N-values:48-35.92)conditions,ranging from oxic to anoxic and brackish to saline.Major element data(SiO_(2) vs.Al_(2)O_(3)+K_(2)O+Na_(2)O)indicate a semi-arid regime,while Paleoclimatic indicators such as Sr/Cu(1.88-37.47)and C-values(0.12-0.93)suggests alter-nating humid and arid conditions.Notably,stable isotope data,reported here for the first time in the Koum Basin,reveal a predominantly terrestrial,fluvial-deltaic C_(3) plant source for organic carbon(δ^(13)C-25.2‰ to -35.2‰)and complex fluid-rock interactions involving meteoric and magmatic-metamorphic fluids under a warm,equatorial climate(δ^(18)O+3.6‰to +24.9‰,δ^(2)H-104‰ to-50‰).The combined mineralogical,geochemical,and isotopic data point to deposition in a tectonically active continental arc setting,with contributions from ocean island arc and passive margin sources.
文摘The advent of civilization has made humans dependent on plants for food and medicine,leading to the intensification of agricultural production.The intense cultivation of crops has resulted in the depletion of available nutrients from soil,thereby demanding the application of excess nutrients to soil to improve yield.Thus,mineral fertilizer discovery and application have,in many ways,contributed greatly to meeting global food demands.However,aside from the positive effects of mineral fertilizers,their excessive application to soil produces large amounts of pollutants that affect environmental sustainability.This necessitates the study of the major mineral fertilizer elements(nitrogen(N),phosphorus(P),and potassium(K)),the forms in which they are applied to soil,and their chemistry/reactions in soil.Here,we reviewed the forms of different N,P,and K mineral fertilizers to provide current knowledge on their constituents,the chemistry of N,P,and K in soil to understand the reactions they undertake in soil,the efficient methods of fertilizer application for environmental sustainability,the effects of mineral fertilizer loss to the environment,and improved fertilization technologies for environmental sustainability.Nanofertilizers are a promising technology for sustainable agricultural production and are discussed in detail in this review.
文摘The Cretaceous Mamu Formation coal samples located within the Northern Anambra Basin were collected, analysed and interpreted using multivariate statistical approach to determine the major, trace and rare elements association with a view to determine the source of the terrestrial rocks, palaeoweathering/climatic conditions and tectonic setting. The dominant oxides such as SiO2, A12O3, Fe2O3, TiO2 and CaO were identified in the coal to suggest terrigenous origin. The ratio of SiO2/Al2O3 of 4.8 suggests that the coal was formed from low land peat associated with freshwater continental marine or blackish water with low salinity as indicated by Sr/Ba and CaO + MgO/K2O + Na2。ratios. The major oxides also revealed stable condition of deposition, low degree of tectonic setting but constant subsidence in the basin. The condition of deposition was acidic in nature as indicated by TiO2/Zr plot. Based on the abundance of Zr, Zn, Ba, Ni, Co, Sr, V, and Y, moderate salinity, sub-oxic to oxic bottom water condition was prevalent and also indication of marine influence. Based on the ratios of La/Yb;La/Sm and Gd/Yb, LREE has higher enrichment than HREE. Humid climatic conditions were observed at the coal formation stage while weak laterization to kaolinization was also evidence.
基金the Internal Grant Agency of Mendel University in Brno(MENDELU,project no.LDF_VP_2019015)。
文摘The positive ecological interaction between gap formation and natural regeneration has been examined but little research has been carried out on the effects of gaps on natural regeneration in forests under different intensities of disturbance.This study evaluates the composition,diversity,regeneration density and abundance of natural regeneration of tree species in gaps in undisturbed,intermittently disturbed,and disturbed forest sites.Bia Tano Forest Reserve in Ghana was the study area and three gaps each were selected in the three forest site categories.Ten circular subsampling areas of 1 m2 were delineated at 2 m spacing along north,south,east,and west transects within individual gaps.Data on natural regeneration<350 cm height were gathered.The results show that the intensity of disturbance was disproportional to gap size.Species diversity differed significantly between undisturbed and disturbed sites and,also between intermittently disturbed and disturbed sites for Simpson’s(1-D),Equitability(J),and Berger-Parker(B-P)indices.However,there was no significant difference among forest sites for Shannon diversity(H)and Margalef richness(MI)indices.Tree species composition on the sites differed.Regeneration density on the disturbed site was significantly higher than on the two other sites.Greater abundance and density of shade-dependent species on all sites identified them as opportunistic replacements of gap-dependent pioneers.Pioneer species giving way to shade tolerant species is a natural process,thus make them worst variant in gap regeneration.
基金financial support from the Shenyang Science and Technology Plan Project(Y17-1-039)。
文摘For the purpose of overcoming the lack of durability problems associated with superhydrophobic surfaces which hitherto has limited their use;we prepared multi-stimuli wettability response coatings using a mixture of fluorocarbon resin and urea-formaldehyde microcapsules filled with fluorosilane via interfacial polymerization process.The microcapsules are of good thermal stability and can be triggered to release their core content on exposure to atmospheric conditions resulting in the increase in the water contact angle from 97°to 151°.The prepared coatings gave good adhesion strength,and also showed an increase in the hydrophobic property after undergoing scratch,solvent and UV accelerated aging test.In addition,they offered good self-healing of the hydrophobic property after an initial loss due to alkaline immersion and oxygen plasma etching.The electrochemical measurements revealed a remarkable impedance recovery and suppression of corrosion activities,suggesting them to be a potential candidate material for corrosion protection.
