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Integration of high-rate filtration using waste-derived biochar as a potential sustainable technology for drinking water supply

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Biochar 2023年第1期5卷 1075-1097页

作者： Fernando García-Ávila Andrés Galarza-Guamán Mónica Barros-Bermeo Emigdio Antonio Alfaro-Paredes Alex Avilés-Añazco Sergio lglesias-Abad Carrera de ingeniería ambiental Facultad de Ciencias QuímicasUniversidad de CuencaCuencaEcuador departamento de Química Aplicada y Sistemas de Producción Grupo de Evaluación de Riesgos Ambientales en Sistemas de Producción y Servicios(RISKEN)CuencaEcuador Professional School of Systems Engineering Research Institute of Science and TechnologyUniversidad César VallejoLimaPeru Carrera de ingeniería ambiental Universidad Católica de CuencaCuencaEcuador

This research aimed to evaluate the efficiency of eucalyptus(E)and bamboo(B)residual biomass biochars as filter materials for drinking water *** efficiencies of these two biochars in the rapid filtration process were evaluated using water(raw,flocculated and settled)at the rate of 120 m^(3)/m^(2)/*** that bamboo biochar manufactured under a slow pyrolysis process"b"(Bb)had the best ***,Bb was evaluated with three different granulometries,and it was found that the effective size with the best performance was the finest(0.6-1.18 mm).Subsequently,this biochar was compared with conventional filter materials such as gravel,sand and anthracite,using different types of water(raw,flocculated and settled)and at different filtration rates(120 and 240 m^(3)/m^(2)/d),and it was found that the filter material with the best performance was precisely biochar,with average removal efficiencies of 64.37%turbidity and 45.08%colour for raw water;93.9%turbidity and 90.75%colour for flocculated water,and 80.79%turbidity and 69.03%colour for settled *** efficiency using simple beds of sand,biochar,anthracite and gravel at the rate of 180 m^(3)/m^(2)/d was 75.9%copper,90.72%aluminium,95.7%iron,10.9%nitrates,94.3%total coliforms and 88.9%fecal *** efficiencies achieved by biochar were higher compared to those of conventional filter *** was also found that biochar contributes to improving the performance of sand and anthracite in mixed ***,it was possible to demonstrate that the volume of washing water required for the biochar is lower compared to the other filter ***,it is recommended to carry out more tests for the purification of water with biochars from rural areas affected by the mining and oil exploitation,as well as the purification of seawater with biochars from coastal areas with residues from dry forests and organic residues from municipalities.

关键词： Biochar Filter medium Rapid filtration Pyrolysis Eucalyptus Bamboo

Modelling fuel loads of understorey vegetation and forest floor components in pine stands in NW Spain

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Forest Ecosystems 2022年第6期9卷 775-789页

作者： Jose A.Vega Stefano Arellano-Perez Juan Gabriel Alvarez-Gonzalez Cristina Fernandez Enrique Jimenez Pedro Cuinas Jose María Fernandez-Alonso Daniel J.Vega-Nieva Fernando Castedo-Dorado Cecilia Alonso-Rego Teresa Fontúrbel Ana Daría Ruiz-Gonzalez Centro de Investigacion Forestal de Lourizan PO Box 12736080PontevedraSpain Unidad de Gestion ambiental y Forestal Sostenible(UXAFORES) Departamento de Ingeniería AgroforestalEscuela Politecnica Superior de IngenieríaUniversidad de Santiago de CompostelaCampus Universitario s/n27002LugoSpain Facultad de Ciencias Forestales Universidad Juarez del Estado de DurangoRío Papaloapan y Blvd.Durango s/nCol.Valle del Sur34120DurangoMexico departamento de ingeniería y Ciencias Agrarias Universidad de LeonCampus de Ponferrada24401PonferradaSpain

In this study,310 destructively sampled plots were used to develop two equation systems for the three main pine species in NW Spain(***;*** and ***):one for estimating loads of understorey fuel components by size and condition(live and dead)and another one for forest floor *** systems of equations were simultaneously fitted for estimating fuel loads using overstorey,understorey and forest floor variables as *** systems of equations included both the effect of pine species and the effect of understorey compositions dominated by ferns-brambles or by woody species,due to their obvious structural and physiological *** general,the goodness-of-fit statistics indicated that the estimates were reasonably robust and accurate for all of the fuel *** best results were obtained for total understorey vegetation,total forest floor and raw humus fuel loads,with more than 76%of the observed variability explained,whereas the poorest results were obtained for coarse fuel loads of understory vegetation with a 53%of observed variability *** reduce the overall costs associated with the field inventories necessary for operational use of the models,the additive systems were fitted again using only overstorey variables as potential *** relationships for fine(derstorey vegetation and total forest floor fuel loads were obtained,indicating the complexity of the forest overstorey-understorey and overstorey-forest floor ***,these models explained around 52%of the observed ***,equations estimating the total understorey vegetation and the total forest floor fuel loads based only on canopy cover were *** models explained only 26%-32%of the observed variability;however,their main advantage is that although understorey vegetation in forested landscapes is largely invisible to remote sensing,canopy cover can be estimated with moderate accuracy,allowin

关键词： Area-based approach Additive equation systems Live and dead fine fuel Pinus pinaster Pinus radiata Pinus sylvestris

Analysis of the role of diffraction in topographic site effects using boundary element techniques

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Earthquake Science 2013年第5期26卷 341-350页

作者： Juan Gomez Doriam Restrepo Juan Jaramillo Camilo Valencia departamento de ingeniería civil Universidad EAFITMedellín Colombia

The role played by the diffraction field on the problem of seismic site effects is studied. For that purpose we solve and analyze simple scattering problems under P and SV in-plane wave assumptions, using two well known direct boundary-element-based numerical methods. After establishing the difference between scattered and diffracted motions, and introducing the concept of artificious and physically based incoming fields, we obtain the amplitude of the Fourier spectra for the diffracted part of the response： this is achieved after establishing the connection between the spatial distribution of the transfer function over the studied simple topographies and the diffracted field. From the numerical simulations it is observed that this diffracted part of the response is responsible for the amplification of the surface ground motions due to the geometric effect. Furthermore, it is also found that the diffraction field sets in a fingerprint of the topographic effect in the total ground motions. These conclusions are further supported by observations in the time-domain in terms of snapshots of the propagation patterns over the complete computational model. In this sense the geometric singularities are clearly identified as sources of diffraction and for the considered range of dimensionless frequencies it is evident that larger amplifications are obtained for the geometries containing a larger number of diffraction sources thus resulting in a stronger topographic effect. The need for closed-form solutions of canonical problems to construct a robust analysis method based on the diffraction field is identified.

关键词： Seismic site effects Topographiceffects Elastic wave scattering Diffractionof in-plane waves

Effective Interaction Force between an Electric Charge and a Magnetic Dipole and Locality (or Nonlocality) in Quantum Effects of the Aharonov–Bohm Type

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Chinese Physics Letters 2021年第3期38卷 39-43页

作者： Gianfranco Spavieri George T.Gillies Miguel Rodriguez Maribel Perez Centro de Física Fundamental Facultad de CienciasUniversidad de Los AndesMérida 5101Venezuela department of Mechanical and Aerospace Engineering University of VirginiaCharlottesvilleVA 22904USA departamento de Física Facultad de Ciencia y TecnologíaUniversidad de CaraboboNaguanagua 2001Venezuela Carrera de ingeniería ambiental Facultad de IngenieríaUniversidad Nacional de ChimborazoRiobamba 100150Ecuador

Classical electrodynamics foresees that the effective interaction force between a moving charge and a magnetic dipole is modified by the time-varying total momentum of the interaction fields. We derive the equations of motion of the particles from the total stress-energy tensor, assuming the validity of Maxwell’s equations and the total momentum conservation law. Applications to the effects of Aharonov–Bohm type show that the observed phase shift may be due to the relative lag between interfering particles caused by the effective local force.

关键词： force. momentum interaction

Comparative carbon emission assessments of recycled and natural aggregate concrete: Environmental influence of cement content

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Geoscience Frontiers 2021年第6期12卷 66-75页

作者： Marian Sabǎu Dan V.Bompa Luis F.O.Silva department of civil and Environmental Engineering Universidad de la Costa080020 BarranquillaColombia department of civil and Environmental Engineering University of SurreyGuildford GU27XHUK departamento de ingeniería civil y Arquitectura Universidad de LimaAvenida Javier Prado Este 4600Santiago de Surco 1503Peru

This work examines the environmental and geochemical impact of recycled aggregate concrete production with properties representative for structural *** environmental influence of cement content,aggregate production,transportation,and waste landfilling is analysed by undertaking a life cycle assessment and considering a life cycle inventory largely specific for the *** obtain a detailed insight into the optimum life cycle parameters,a sensitivity study is carried out in which supplementary cementitious materials,different values of natural-to-recycled aggregate content ratio and case-specific transportation distances were *** results show that carbon emissions were between 323 and 332 kgCO_(2)e per cubic metre of cement only natural aggregate *** values can be reduced by up to 17%by replacing 25%of the cement with fly *** contrast,carbon emissions can increase when natural coarse aggregates are replaced by recycled aggregates in proportions of 50%and 100%,and transportation is not included in ***,the concrete with 50%recycled aggregate presented lower increase,only 0.3%and 3.4%for normal and high strength concrete,*** some cases,the relative contribution of transportation to the total carbon emissions increased when cement was replaced by fly ash in proportions of 25%,and case-specific transportation distances were *** absolute values,the concrete mixes with 100%recycled aggregates and 25%fly ash had lower carbon emissions than concrete with cement and natural aggregates *** environmental benefits can be obtained when the transportation distances of fly ash are relatively short(15–25 km)and the cement replacement by fly ash is equal or higher than 25%,considering that the mechanical properties are adequate for practical *** observations from this paper show that recycled aggregate concrete with strength characteristics representative for structural members can have lowe

关键词： Life cycle assessment Recycled aggregate Natural aggregate Transportation distance OpenLCA

Assessment of compressive strength of jet grouting by machine learning

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 102-111页

作者： Esteban Diaz Edgar Leonardo Salamanca-Medina Roberto Tomas departamento de ingeniería civil Escuela Politécnica SuperiorUniversidad de AlicanteP.O.Box 99E-03080AlicanteSpain

Jet grouting is one of the most popular soil improvement techniques,but its design usually involves great uncertainties that can lead to economic cost overruns in construction *** high dispersion in the properties of the improved material leads to designers assuming a conservative,arbitrary and unjustified strength,which is even sometimes subjected to the results of the test *** present paper presents an approach for prediction of the uniaxial compressive strength(UCS)of jet grouting columns based on the analysis of several machine learning algorithms on a database of 854 results mainly collected from different research *** selected machine learning model(extremely randomized trees)relates the soil type and various parameters of the technique to the value of the compressive *** the complex mechanism that surrounds the jet grouting process,evidenced by the high dispersion and low correlation of the variables studied,the trained model allows to optimally predict the values of compressive strength with a significant improvement with respect to the existing ***,this work proposes for the first time a reliable and easily applicable approach for estimation of the compressive strength of jet grouting columns.

关键词： Jet grouting Ground improvement Compressive strength Machine learning

Comparative carbon emission assessments of recycled and natural aggregate concrete: Environmental influence of cement content

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Geoscience Frontiers 2021年第6期12卷 72-81页

作者： Marian Sab?u Dan V.Bompa Luis F.O.Silva department of civil and Environmental Engineering Universidad de la Costa department of civil and Environmental Engineering University of Surrey departamento de ingeniería civil y Arquitectura Universidad de Lima

This work examines the environmental and geochemical impact of recycled aggregate concrete production with properties representative for structural applications. The environmental influence of cement content, aggregate production, transportation, and waste landfilling is analysed by undertaking a life cycle assessment and considering a life cycle inventory largely specific for the region. To obtain a detailed insight into the optimum life cycle parameters, a sensitivity study is carried out in which supplementary cementitious materials, different values of natural-to-recycled aggregate content ratio and case-specific transportation distances were considered. The results show that carbon emissions were between 323 and 332 kg CO2e per cubic metre of cement only natural aggregate concrete. These values can be reduced by up to 17% by replacing 25% of the cement with fly ash. By contrast, carbon emissions can increase when natural coarse aggregates are replaced by recycled aggregates in proportions of 50% and 100%, and transportation is not included in analysis. However, the concrete with 50% recycled aggregate presented lower increase, only 0.3% and 3.4% for normal and high strength concrete, respectively. In some cases, the relative contribution of transportation to the total carbon emissions increased when cement was replaced by fly ash in proportions of 25%, and case-specific transportation distances were considered. In absolute values, the concrete mixes with 100% recycled aggregates and 25% fly ash had lower carbon emissions than concrete with cement and natural aggregates only. Higher environmental benefits can be obtained when the transportation distances of fly ash are relatively short(15–25 km) and the cement replacement by fly ash is equal or higher than 25%, considering that the mechanical properties are adequate for practical application. The observations from this paper show that recycled aggregate concrete with strength characteristics representative for s

关键词： Life cycle assessment Recycled aggregate Natural aggregate Transportation distance OpenLCA

Environmental geochemistry:Introduction

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Geoscience Frontiers 2022年第1期13卷 374-375页

作者： Luis F.O.Silva Marcos L.S.Oliveira department of civil and Environmental.Universidad de la Costa CUCCalle 58#55-66BarranquillaAtlánticoColombia departamento de ingeniería civil y Arquitectura Universidad de LimaAvenida Javier Prado Este 4600Santiago de Surco 1503Peru

Assessing the physical,geographic,chemical,and geological aspects are important to understand environmental impacts as well as health concerns in view of building a more sustainable planet with circular economies that would last for the foreseeable *** the recent years,the significance of incorporating ecosystem,anthropogenic activities,and climate has fortified from being an academic concern(e.g.,WEF,2011)into a broadly societal concern as the forecasted realities of environmental deterioration and global climate change come to pass.

关键词： geochemistry climate planet

Novel strategies to tailor the photocatalytic activity of metal–organic frameworks for hydrogen generation: a mini-review

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Frontiers in Energy 2022年第5期16卷 734-746页

作者： Luis A.ALFONSO-HERRERA Leticia M.TORRES-MARTINEZ J.Manuel MORA-HERNANdeZ Universidad Autónoma de Nuevo León UANLFacultad de Ingeniería CivilDepartamento de Ecomateriales y EnergíaAv.Universidad S/N Ciudad UniversitariaSan Nicolás de los GarzaNuevo León 66455México Centro de Investigación en Materiales Avanzados S.C.(CIMAV)Miguel de Cervantes No.120.Complejo Ind.ChihuahuaChihuahuaChih 31136México CONACyT-Universidad Autónoma de Nuevo León UANLFacultad de Ingeniería CivilDepartamento de Ecomateriales y EnergíaAv.Universidad S/N Ciudad UniversitariaSan Nicolás de los GarzaNuevo León 66455México

This review provides a recompilation of the most important and recent strategies employed to increase the efficiency of metal-organic framework(MOF)-based systems toward the photocatalytic hydrogen evolution(PHE)reaction through specific strategies:tailoring the photocatalytic activity of bare MOFs and guest@MOF composites,formation of heterojunctions based on MOFs and various photocatalysts,and inorganic photocatalysts derived from *** to the data reported in this mini-review,the most effective strategy to improve the PHE of MOFs relies on modifying the linkers with new secondary building units(SBUs).Although several reviews have investigated the photocatalytic activity of MOFs from a general point of view,many of these studies relate this activity to the physicochemical and catalytic properties of ***,they did not consider the interactions between the components of the photocatalytic *** study highlights the effects of strength of the supramolecular interactions on the photocatalytic performance of bare and MOF-based materials during PHE.A thorough review and comparison of the results established that metal-nanoparticle@MOF composites have weak van der Waals forces between components,whereas heterostructures only interact with MOFs at the surface of bare *** material derivatives from MOFs,we found that pyrolysis destroyed some beneficial properties of MOFs for ***,we conclude that adding SBUs to organic linkers is the most efficient strategy to perform the PHE because the SBUs added to the MOFs promote synergy between the two materials through strong coordination bonds.

关键词： metal-organic frameworks(MOFs) photocatalytic hydrogen evolution MOF heterojunctions materials derived from MOFs bandgap recombination