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Characterization and Modification of a Clay Mineral Used in Adsorption Tests

Journal of Minerals and Materials Characterization and engineering 2015年第4期3卷 277-288页

作者： Natália Costa Dias Patrícia Arns Steiner Maria Cristina Borba Braga Water Resources and Environmental Engineering Post-Graduate Program Department of Hydraulics and Sani-tation Parana Federal University Curitiba Brazil

Clay minerals are widespread in natural systems and have been widely used for the removal of pollutants. In this study, natural expanded vermiculite was used in adsorption tests to remove ammonium nitrogen from landfill leachate. The modification of vermiculite was carried out using NaOH and HCl, and for both modifications the best concentration was 0.1 mol/L. The results produced by XRD (X-ray diffraction) showed that Al replaced K after modification of the vermiculite using HCl and that Mg and Na replaced K after modification using NaOH. It was observed that the adsorption capacity increased as the percentage in mass of K diminished. The Langmuir is the isotherm that presents the best fit of the data, and the values of RL (the Langmuir coefficient) suggest that the adsorption is linear. The thermodynamic parameters indicate that the process is spontaneous and endothermic, that there is a high affinity between the adsorbate and the adsorbent, and that physical adsorption is prevalent.

关键词： Adsorption Isotherms Adsorption Thermodynamics Clay Minerals Expanded Vermiculite Landfill Leachate Vermiculite

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ANALYSIS OF NITROGEN FLOW IN FOOD WASTE: A CASE STUDY OF THE UNIVERSITY RESTAURANT-UNB 32nd

ANALYSIS OF NITROGEN FLOW IN FOOD WASTE: A CASE STUDY OF THE...

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32nd European Biomass Conference and Exhibition, EUBCE 2024

作者： Ramos, Arthur Augusto Frasson De Brites, Eneida Campos Felipe Soares, Raquel Moraes Silveira, Edgar A. Contreras, Francisco University of Brasilia Department of Civil and Environmental Engineering DF Brasilia70910-900 Brazil University of Brasilia Graduate Program on Environmental Technology and Water Resources Department of Civil and Environmental Engineering DF Brasilia70910-900 Brazil Federal Institute of Education Science and Technology of Brasília Estrutural Campus DF Brasília71250-000 Brazil University of Brasília Mechanical Sciences Graduate Program Laboratory of Energy and Environment DF Brasilia70910-900 Brazil

With the projected global population reaching 9.7 billion by 2050, the production and consumption of food continue to escalate. Nitrogen is pivotal in this landscape due to its significance in living organisms and the environmental repercussions associated with nutrient-rich waste. Inappropriate disposal of such residues contributes to nitrogen release into the environment, impacting aquatic ecosystems and precipitating the generation of greenhouse gases. This study tackles the global challenge of effectively managing nitrogen in food waste by utilizing Material Flow Analysis (MFA) as a tool to comprehend this cycle. The analysis uncovered that vegetables, legumes, and fruits constitute the primary sources of waste generation, while meats, despite their lower mass, account for a substantial proportion of total nitrogen depletion. In the surveyed month of October 2023, 174,834 meals were served, resulting in an average food consumption N-footprint of 0.003 kg of nitrogen discarded per individual meal within the restaurant’s organic waste. These findings indicate that 65% of nitrogen is consumed in meal form, while 35% is discarded as organic solid waste. However, 53% of the nitrogen in the residues originates from food preparation processes, with food preparation responsible for over half of this figure. A deeper process analysis reveals that vegetables have low nitrogen concentrations, although they significantly contribute to waste at all stages. In contrast, meats and eggs, with higher nitrogen concentrations, emerge as noteworthy contributors to the overall nitrogen content in waste. Vegetables and meats contribute about 50% and 45% of the total nitrogen, respectively. These outcomes substantially enhance our comprehension of waste generation dynamics and nutrient utilization at the university restaurant, assisting with waste management, design of sustainable menus, reduction of food waste, and optimized resource utilization, contributing to sustainability and re

关键词： Effluent treatment

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Spatial pattern of sediment transport for analysis of precipitation direction and magnitude in the upper Lematang river sub-basin 4

Spatial pattern of sediment transport for analysis of precip...

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4th Geomatics International Conference 2019, GeoICON 2019

作者： Sarino Yuono, Agus Lestari Putranto Dinar, D.A. Civil Engineering and Planning Study Program Faculty of Engineering University of Sriwijaya Jl. Raya Inderalaya Km. 32 Ogan Ilir Regency Inderalaya South Sumatera Province Indonesia Civil Engineering Post Graduate Study Program Faculty of Engineering University of Sriwijaya Jl. R. Soeprapto Bukit Besar Palembang City South Sumatera Province Indonesia

The high level of erosion that occur in Musi river basin has improved a tremendous impact on sedimentation in downstream areas and has resulted in many infrastructure of water is disturbed, such as silting of irrigation channels, siltation of rivers which disrupt the flow of transport stream and increasing the risk of flooding, high sedimentation in the port basin, low quality of water and the rising costs of water treatment. This study utilizes techniques terrain models Digital (Digital Elevation Model/DEM) to analysis the spatial distribution of the potential for erosion and sources of sedimentation, as well as the direction of the flow of sediment into channels as well as its relationship with outlet in branching river as the supplies to be sediment to the river flow. The method used in this study using a spatial model analysis with the help of GIS in analysing and presenting the level of erosion and deposition by utilizing modelling slope and kinetic energy of rainfall to estimate the index erosivity and distribution pattern of sediment into the river channel. This research was conducted at the upper Lematang river sub basin with area 412,638 Ha, which are classified into 11 sub-chatments with the highest altitude is 3.159 m above sea level (Dempo Valley) and the lowest is 126 m above sea level (Talang tinggi Valley). Analytical results have been tested by taking a fine sediment sampling in each sub-watershed in the analysis and is taken along the channel network and compare the observed patterns with the results predicted by the model analysis of soil erosion. Overall, erosion by high intensity tends to occur in the relationship between the different vegetation coverage, the barren land and open land used for farms and land used for mining. Approximately 45-65.5% slope bad condition because the vegetation has been open, so it can be seen the amount of erosion in the area is 2.139 ton/ha/year, at the sloping is 1.8239 ton/ha/year. © 2019 Published under licence

关键词： Erosion

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Sustainable alternatives in developing countries: Preliminary performance assessment and design optimization on the Fitima children's day care and medical centre in Ouagadougou, Burkina Faso

Sustainable alternatives in developing countries: Preliminar...

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27th International Conference on Passive and Low Energy Architecture: Architecture and Sustainable Development, PLEA 2011

作者： Liu, Ning Jobard, Nicolas School of architecture Civil and Environmental Engineering Swiss Federal Institute of Technology Lausanne Switzerland EPFL-UCL-ENSA Toulouse Post-Graduate Architecture and Sustainable Development Building for Climate Associated Architects-Urbanists Paris France

ISBN: (纸本)9782874632761

Nowadays more than 70% of the world population live in the developing countries. To tackle the global challenges of Climate Change, it is vital to create a network of know-how on sustainable design issues between the industrialised world and the developing world. This paper reviews the adaptability of some acknowledged passive sustainable principles in the case of a NGO financed building project in Ouagadougou, Burkina Faso. A multi-fold assessment grid is formulated to evaluate the performances of the initial building schemes. The study also combines the methodical analysis with the use of digital tools for the data provision and comparison. The optimization results demonstrate the positive impact of a solid preliminary assessment phase in the building conception process. Especially in poor countries where materials and equipments are limited, the preliminary study is decisive to make the intelligent use of available budget and resources.

关键词： Developing countries

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Influence of concrete compressive strength on the debonding failure of externally bonded carbon fiber reinforced polymers

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Journal of Building Pathology and Rehabilitation 2021年第1期6卷 1-15页

作者： Garcez, Mônica Regina Rohden, Abrahão Bernardo Meneghetti, Leila Cristina Gravina, Rebecca Civil Engineering Post-Graduation Program: Construction and Infrastructure Federal University of Rio Grande Do Sul Av. Osvaldo Aranha 99 7th floor room 706 Porto Alegre 90035-190 RS Brazil Environmental Engineering Post-Graduation Program Regional University of Blumenau Blumenau SC Brazil Department of Structural and Geotechnical Engineering University of São Paulo São Paulo SP Brazil Department of Civil and Infrastructure Engineering Royal Melbourne Institute of Technology Melbourne VIC Australia

This paper investigates the interactions between externally bonded FRP and high strength concrete substrate in small scale reinforced concrete beams strengthened with CFRP. The bond mechanism was assessed through beam-tests adapted from ASTM, designed to simulate normal and shear stresses induced at the FRP/concrete interface. The beams were 600 mm long, with a square 150 mm × 150 mm cross-section, two 5 mm steel reinforcing bars, 6.3 mm steel stirrups spaced 75 mm apart, one single layer of externally bonded CFRP, and concrete compressive strength of 30 MPa, 50 MPa, 80 MPa, or 90 MPa. The mechanisms of damage initiation and debonding propagation showed to be highly dependent on the load transferring and the stress redistribution after concrete cracking. The use of high concrete compressive strength affected the pre-cracking response, the stress transfer, and the overall ductility at failure, resulting in a less effective FRP strengthening scheme. For service conditions, the strains in the FRP were lower, the higher the concrete compressive strength. The FRP strains at failure were below the maximum strain level to avoid intermediate crack-induced debonding determined according to current design standards. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

关键词： Beam test CFRP Compressive strength Concrete Debonding Intermediate crack

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Accuracy Improvement of ASTER Stereo Satellite Generated DEM Using Texture Filter

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Geo-Spatial Information Science 2010年第4期13卷 257-262页

作者： Mandla V.Ravibabu Kamal Jain Surendra Pal Singh Naga Jyothi Meeniga Center for GIS School of Geography and Environmental ScienceMonash UniversityClayton CampusVICAustralia Environmental Water Resource and Transportation Engineering DivisionSchool of Mechanical & Building ScienceVellore Institute of Technology(VIT)-University Vellore-632 014Tamil NaduIndia Geomatics Engineering Section Department of Civil EngineeringIndian Institute of Technology RoorkeeRoorkee-247667U.A.India Post Graduate Student(GST) Institute of Science and TechnologyJNTUHyderabadIndia

The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite ***,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital *** of the most important steps in such deployment is the stereo matching process for conjugation point(pixel) establishment:very difficult in modelling any homogenous areas like water cover or forest canopied areas due to the lack of distinct spatial *** a result,application of automated procedures is sure to generate erroneous elevation *** this paper,we present and apply a method for improving the quality of stereo DEMs generated via utilization of an entropy texture *** filter was applied for extraction of homogenous areas before stereo matching so that a statistical texture filter could then be applied for removing anomalous evaluation values prior to interpolation and accuracy assessment via deployment of a spatial correlation *** exemplification,we used a stereo pair of ASTER 1B images.

关键词： ASTER digital elevation model extraction stereo matching texture filter quality improvement

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Analysis and structural design of a building with multiple floors in composite steel and concrete structure

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Discover civil engineering 2024年第1期1卷 1-19页

作者： de Lima, Douglas Mateus Silva, Waltner Wagner Nunes López-Yánez, Pablo Aníbal da Silva Medeiros, Iálysson Technology Center Graduate Program in Civil and Environmental Engineering Federal University of Pernambuco AcademicCenterof Agreste Caruaru Brazil Department of Civil and Environmental Engineering Federal University of Pernambuco Recife Brazil

This paper consists of the structural design and analysis of a commercial office building with seventeen floors using a composite structure of steel and reinforcement concrete. The static and modal analysis of the structure was performed using SAP 2000 software. To this end, the initial design criteria were defined, and subsequently, the structural design was carried out, defining the structural system, the selection of the construction method and materials used, and the determination of the actions and combinations used. The steel decking slabs, dimensioned using the tables provided by the manufacturer, and the composite beams were verified in both the construction and final stages in accordance with current regulatory criteria, with consideration of the shear connectors in this final post-cure stage. For the analysis of the columns, geometric nonlinear analysis was incorporated to determine the stresses and displacements of the steel columns. The modal analysis of the structure provided the vibration modes, showing that the first and second modes have frequencies lower than 1 Hz, confirming the overall flexibility of the structure against wind actions. Finally, beam-beam and beam-column connections were designed. Thus, this article provides a detailed description of a practical application of the design and analysis of a composite steel and concrete structure, contributing to the advancement of technical and practical knowledge of design, technological innovation, structural safety and direct application in engineering projects.

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Characterization of vulnerability of road networks to fluvial flooding using SIS network diffusion model

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Journal of Infrastructure Preservation and Resilience 2020年第1期1卷 1-13页

作者： Abdulla, Bahrulla Kiaghadi, Amin Rifai, Hanadi S. Birgisson, Bjorn Zachry Department of Civil Engineering Texas A & ampM University 3136 TAMU College StationTX77843 United States Research Associate Oden Institute for Computational Engineering and Sciences University of Texas at Austin AustinTX78712 United States Environmental Engineering Graduate Program N138 Engineering Building 1 HoustonTX77204-4003 United States

This study aims to characterize the vulnerability of road networks to fluvial flooding using a network diffusion-based method. Various network diffusion models have been applied widely for modeling the spreading of contagious diseases or capturing opinion dynamics in social networks. By comparison, their application in the context of physical infrastructure networks has just started to gain some momentum, although physical infrastructure networks also exhibit diffusion-like phenomena under certain stressors. This study applies a susceptible-impacted-susceptible (SIS) diffusion model to capture the impact of flooding on the road network connectivity. To that end, this paper undertook the following four steps. First, the road network was modeled as primal graphs and nodes that were flood-prone (or the origins of the fluvial flood) were identified. Second, temporal changes in the flood depth within the road network during a flooding event were obtained using a data-driven geospatial model. Third, based on the relationship between vehicle speed and flood depth on road networks, at each time step, the nodes in the road network were divided into two discrete categories, namely functional and closed, standing for Susceptible and Impacted in the SIS diffusion model, respectively. Then, two parameters of the SIS model, average transition probabilities between states, were estimated using the results of the hydraulic simulation. Fourth, the robustness of the road network under various SIS diffusion scenarios was estimated, which was used to test the statistical significance of the difference between the robustness of the road network against diffusions started from the randomly chosen nodes and nodes with different high centrality measures. The methodology was demonstrated using the road network in the Memorial super neighborhood in Houston. The results show that diffusive disruptions that start from nodes with high centrality values do not necessarily cause a more significan

关键词： Floods

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Investigation of the supply chain of prefabricated wooden doors

Investigation of the supply chain of prefabricated wooden do...

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18th Annual Conference of the International Group for Lean Construction, IGLC 18

作者： De Melo, Reymard Sávio S. Da Alves, Thais C.L. Graduate Program in Structural Engineering and Construction Federal University of Ceará Fortaleza CE Brazil J.R. Filanc Construction Engineering and Management Program Department of Civil Construction and Environmental Engineering San Diego State University San Diego CA 92182-1324 United States

This study focused on pre-fabricated wooden doors and their supply chain, which have all of its components pre-assembled by the supplier. The literature indicates that supply chain management in construction has four roles. One concerns the transfer of activities from the site to the supply chain to take advantage of better conditions at the fabricator's end. This role assumes that fabricators are in a better environment to perform certain tasks and deliver better products that can be quickly installed on site, as the product is pre-assembled. This is the first working hypothesis tested in study. A second working hypothesis is that off-site prefabricated doors have short lead times for fabrication and on-site installation and present fewer problems during installation when compared to traditional doors. The two-phase research comprised a preliminary study and two in-depth case studies about pre-fabricated wooden doors. Wooden doors presented problems related to the installation and final product quality regardless of the type of project. Some advantages of prefabricated elements were lost due lack of trust between contractors and suppliers, lack of consideration of preconditions necessary for successful site installation, and lack of standardization and tolerance management resulted in suboptimal solutions during the installation phase.

关键词： Fabrication

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Influence of rice husk ash and hybrid fiber on engineering properties of densified high-performance fiber-reinforced concrete

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Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 2023年第11期237卷 2845-2857页

作者： Vo, Duy-Hai Nguyen, Minh-Hieu Nguyen, May Huu Hwang, Chao-Lung Huynh, Trong-Phuoc The University of Danang University of Technology and Education Danang Viet Nam Vinh Long Department of Construction Vinh Long Viet Nam Civil and Environmental Engineering Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan Department of Bridge and Tunnel Faculty of Civil Engineering University of Transport Technology Hanoi Viet Nam Taiwan Building Technology Center National Taiwan University of Science and Technology Taipei Taiwan Faculty of Civil Engineering College of Engineering Can Tho University Can Tho Viet Nam

Conventional concrete significantly affects the environment due to high CO2 emission into the atmosphere during the production process. In order to improve concrete performance and arrest the incidence of global warming, the use of additive materials for cement replacement has been promoted worldwide. This study was designed to investigate the mechanical properties of high-performance fiber-reinforced concrete (HFRC) produced using rice husk ash (RHA) and hybrid fiber (HF) in accordance with the densified mixture design algorithm (DMDA) mix design method. Samples were produced using RHA as a direct replacement for cement at 10%, 20%, and 30%. HF, comprising steel and polypropylene fibers, was added (by volume) to the 20% RHA group mixture to improve the HFRC sample properties. Based on the experimental results, higher RHA contents had a generally negative effect on the fresh properties of the HFRC mixtures. Compressive strength values ranged from 53 to 72 MPa with various RHA and HF content. RHA replacement levels up to 20% had an insignificant effect on the strength development and dynamic modulus of the HFRC samples. However, the addition of HF improved splitting tensile strength, flexural strength, and dynamic modulus remarkably at all curing ages. Furthermore, the 91-day drying shrinkage was in the ranges of 0.032%–0.039% and 0.023%–0.034% using different RHA and HF levels, respectively. Increasing both RHA and HF contents significantly reduced drying shrinkage in the samples. Multivariable regression was also performed, clarifying that all tested results were consistent and had good correlations. The results of this study also provide a potentially effective use for abundantly available industrial waste products such as fly ash (FA) and RHA to promote the production of greener and more sustainable concrete. © IMechE 2023.

关键词： Bending strength

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