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Heavy metal removal using different parts of typha latifolia

Journal of Bionanoscience 2018年第1期12卷 87-91页

作者： Sudarsan, J. Annadurai, R. Kumar, K.S. Nithiyanantham, S. Department of Civil and Environmental Engineering SRM University Kanchipuram Dt. Kattankulathur Tamilnadu603203 India Post Graduate and Research Department of Physics Ultrasonics NDT and Bio-Physics Divisions Thiru. VI. Kalyanasundaram India

Govt. Arts and Science College, Thiruvarur 610003, Tamilnadu, India (Affiliation-Bharathidasan University, Thiruchirapalli) Tannery Water is an essential element for all biotic components, urbanization and industrialization;various contaminants are added to water sources through uncontrolled discharges resulting in the gradual degradation of water quality. Metals and heavy metals are toxic elements mostly released from tannery industries. Improper wastewater treatment and discharges of untreated wastewater into the water bodies will leads to several impacts on the environment. Existing treatment technologies involves large amount of initial investment, recurring expenditure and chemicals. To minimize these issues many studies were conducted to identify the different viable technologies as an alternative. This study assessed the efficiency of Constructed Wetland (CW) for the removal of chromium, from the leather processing industries. Plants were grown in hydrophonic condition. Tannery wastewater sample were collected and analyzed for pH, biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and total dissolved solids (TDS), dissolved oxygen (DO), hardness. Heavy metals were analyzed using Atomic Absorption Spectrometer (AAS) before being introduced into the pilot units. Three pilot units were designed as per the EPA design criteria and the same was vegetated using Typha latifolia and fourth unit was left as and unvegetated control. Generally, the concentration of these five elements in the roots was 3 to 15 times higher than shoots. Based on the analysis it was found that the raw wastewater has the discharge limit of BOD and COD (30 mg/l and 250 mg/l). The observed results and concluded as T. latifolia are suitable for removal of Cr. © 2018 American Scientific Publishers.

关键词： Heavy metals

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Influence of CDW Recycled Aggregate on Drying Shrinkage of Mortar

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Open Journal of civil engineering 2012年第2期2卷 53-57页

作者： Paulo Roberto Lopes Lima Monica Batista Leite Civil and Environmental Engineering Post-Graduate Program State University of Feira de Santana Feira de Santana Bahia Brazil

The use of fine recycled aggregates as raw material in the production of mortars appears as a good alternative to minimize waste disposal, so as to reduce natural resources consumption and to find and supply suitable substitutes for natural aggregates. However, the use of this alternative material in a safe way must be carried out by a wide investigation of its long term behavior. In this way, this paper will examine the mechanical strength, physical properties and drying shrinkage of mortar, which use recycled fine aggregates that have originated from construction and demolition waste (CDW) containing mortar (55%), ceramic (26%) and concrete (16%). Two natural mortars, made with natural sand, were produced with cement/sand ratios of 1:4 and 1:8 (by weight) and a fixed consistency index of 260 +10 mm. Recycled mortar was produced with 50% of substitution rate, in volume, of natural aggregate by recycled one. Results show that recycled mortars present higher total porosity, absorption rate and drying shrinkage than reference mortar.

关键词： Recycled Mortar Construction and Demolition Waste Drying Shrinkage Recycled Aggregate

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Influence of chord stresses on the strength of RHS joints 9

Influence of chord stresses on the strength of RHS joints

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9th International Conference on Advances in Steel Structures, ICASS 2018

作者： Mendes, Flávio F. de Lima, Luciano R.O. da Vellasco, Pedro C. G. S. Rodrigues, Monique C. Neves, Luis F.C. PGECIV - Civil Engineering Post-Graduate Program UERJ - State University of Rio de Janeiro Brazil Structural Engineering Department UERJ - State University of Rio de Janeiro Brazil INESCC Civil Engineering Department University of Coimbra Portugal

ISBN: (纸本)9889914093

Extensive work has been performed to address the technological and design issues of tubular joints in the last decades. Several international design codes and recommendations explicitly cover the design of tubular joints such as Eurocode 3, ISO14346 and NBR16239. Experimental results on the influence of the chord stresses over the brace load capacity have been published in the literature. These results showed that compressive chord stresses considerably reduce the joint resistance. However, very few studies indicated the same reduction in load carrying capacity for joints under the action of chord tensile forces. To investigate this influence, an experimental program comprising thirteen tests was carried out, i.e. tests without chord axial forces;tests with compressive chord forces;and other ones with tensile chord forces. The obtained results were compared to the design provisions. This assessment indicated that the results obtained for chords without axial forces and with compressive forces, in experiments were safe when compared to the values predicted by all the investigated standards. On the other hand, the results associated with cases with chord tension forces proved to be conservative. Copyright © 2018 by The Hong Kong Institute of Steel Construction.

关键词： Software testing

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Structural behaviour of T RHS joints subjected to chord axial force 15

Structural behaviour of T RHS joints subjected to chord axia...

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Proceedings of the 15th International Symposium on Tubular Structures, ISTS 2015

作者： Nizer, A. De Lima, L. Da S. Vellasco, P. De Andrade, S. Da S. Goulart, E. Da Silva, A.T. Da C. Neves, L.F. PGECIV – Civil Engineering Post-Graduate Program UERJ – State University of Rio de Janeiro Brazil Structural Engineering Department UERJ – State University of Rio de Janeiro Brazil INESCC Civil Engineering Department University of Coimbra Portugal

ISBN: (纸本)9781138028371

This paper presents an experimental and numerical analysis of the chord normal stresses influence on the "T" tubular joints behaviour. The experimental program consisted of six tests: two without chord axial forces;two with compressive chord forces;and the remaining two with tensile chord forces. These results were compared to numerical results obtained with the aid of the ANSYS 12.0 software, and to the design provisions present in the: Eurocode 3;NBR 16239:2013 Brazilian standard and ISO 14346. This assessment indicated that the results obtained for chords without axial forces and with compressive forces, in both experiments and numerical analyses, were safe when compared to the values predicted by all the investigated standards, where the best fit was obtained by ISO 14346. On the other hand, the results associated to cases with chord tension forces proved to be conservative. © 2015 Taylor & Francis Group, London.

关键词： Software testing

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Determination of time zero in high strength concrete containing superabsorbent polymer and nano-silica

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-12页

作者： Cunha, T.A. Francinete, P. Manzano, M.A. Aidar, L.A. Borges, J.G. Silva, E.F. Post-Graduate Program in Structures and Civil Construction (PECC/UnB) University of Brasília Brasília Federal District Brazil Civil Engineering Department (ENC/UnB) University of Brasília Brasília Federal District Brazil

The autogenous shrinkage is a phenomenon that occurs due to the appearance of tensile stresses in capillary pores. Inherent in the hydration process, not depending on external interference. In high strength concrete, autogenous shrinkage is most pronounced, due to the refinement of microstructure, the high cement content, presence of mineral addictions and low water/cement ratio, which interfere in the transport of water curing. In this context, Superabsorbent polymers (SAP) stand out for their ability to reduce or eliminate the autogenous shrinkage, because they absorb large amounts of water, which is subsequently released into the matrix, avoiding self-desiccation and the onset of tensile stresses (internal curing). However, studies show that SAP can reduce the mechanical strength, which can be compensated by addiction of Nano-silica (NS). In this paper, the effect of these additions in Time Zero (T₀) was evaluated. T₀ determines the time at which the material starts to behave as a solid, with the development of a rigid mineral skeleton to oppose the volumetric variations that occurs in the paste, which can lead to cracking, compromising esthetics, durability, and structures safety. The ultrasonic pulse velocity test performed the T₀, which measures the velocity of propagation of an ultrasonic wave through the material and is taken as the time when a sudden change occurs at this velocity. Nine blends were made containing SAP and NS, where it was found that SAP addition increases the T₀ (up to 11%), while NS decrease its value (in 55%). © 2016, Springer International Publishing Switzerland.

关键词： High performance concrete High strength concrete Nano-silica Superabsorbent polymer Time zero Ultrasonic pulse velocity

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Fiber reinforced polymers for historical bridges upgrading: a fatigue life assessment

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Journal of Building Pathology and Rehabilitation 2023年第1期8卷 1-11页

作者： Garcez, Mônica Regina Meneghetti, Leila Cristina Post-Graduate Program in Civil Engineering: Construction and Infrastructure Federal University of Rio Grande do Sul Porto Alegre Brazil Department of Structural and Geotechnical Engineering University of São Paulo São Paulo Brazil

Upgrading historical structures is one of the most interesting applications of fiber reinforced polymers in construction. Historical bridges are frequently post-strengthened to increase load carrying capacity of structural elements, aiming to bear heavier commercial traffic. Fatigue life becomes crucial since the lack of available fatigue models leads to superficial analysis considering the same S–N curves for different strengthening systems and steel stress ranges. This paper uses an extensive database with experimental data from the literature to adjust linear regression models to characterize the large scatter between the results of fatigue tests from different sources. Distinct fatigue models have been developed considering three categories: externally bonded reinforcement with strips/sheets and new surface-mounted reinforcement. The different declivities found for the adjusted fatigue life models accurately represent the fatigue behavior of the post-strengthened structural elements with the assessed systems and techniques. The results support design decisions to avoid future unnecessary interventions. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

关键词： Fatigue life Fiber reinforced polymers Historical bridges Linear regression analysis

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Corrigendum to “Assessing the willingness of residential electricity consumers to adopt demand side management and distributed energy resources: A case study on the Japanese market” [Energy Pol. (137) 111169]

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Energy Policy 2025年 198卷

作者： Nikolaos Iliopoulos Miguel Esteban Shogo Kudo Graduate Program in Sustainability Science – Global Leadership Initiative Building of Environmental Studies The University of Tokyo 5-1-5 Kashiwanoha Kashiwa City Chiba 277-8563 Japan Research Institute of Sustainable Future Society Faculty of Civil and Environmental Engineering 60-106 3-4-1 Okubo Shinjuku-ku Tokyo 169-8555 Japan Waseda University Japan

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Identification of spatial potential flood-prone area using topographic wetness index under the digital elevation model of Kr. Keureuto watershed, North Aceh. 5

Identification of spatial potential flood-prone area using t...

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5th Aceh International Symposium on civil engineering 2024, AISCE 2024

作者： Rizalihadi, Maimun Meilianda, Ella Yulianur, Alfiansyah Away, Yuwaldi Doctoral Program Post Graduate Program Syiah Kuala University Banda Aceh Indonesia Civil Engineering Department Syiah Kuala University Banda Aceh Indonesia Electro and Computer Engineering Department Syiah Kuala University Banda Aceh Indonesia

Floods are the most frequent disaster events in Lhoksukon, resulting in significant losses and community and environmental damage. Floods are generated by several factors, consisting of hydrometeorological, topographical, geological, soil, and human activities. Topography is a key controlling factor in flood initiation. Topographic analysis for detecting flood susceptibility, especially flood inundation, can be conducted using the TWI. The research aims to identify the potential spatial distribution of flood-prone areas based on TWI and assess the model accuracy using the ROC-AUC method. A case study was conducted in the Kr. Keureuto watershed. of North Aceh. TWI analysis is based on the topography of an area denoted by extracting DEM using GIS to create slope, flow direction, and flow accumulation. Higher TWI values are associated with higher flood susceptibility. The results show that the value of TWI is approximately 1.571-27.147, showing that more than 20% of area are potentially flood inundations with high and very hight rating of flood susceptibility. Furthermore, based on the analysis using field observation flood is obtained the AUC value of 71,60%. It can be concluded that the spatial model of flood-prone using TWI is good and effective for determining flood prone region in the Kr. Keureuto River basin © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Watersheds

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A neural network modelling of steel joint block shear capacity

A neural network modelling of steel joint block shear capaci...

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9th International Conference on the Application of Artificial Intelligence to civil, Structural and environmental engineering, AIcivil-Comp 2007

作者： Rodrigues, F. Neto, L. Biondi Da S. Vellasco, P.C.G. De Lima, L.R.O. Vellasco, M.M.B.R. Post-Graduate Program in Civil Engineering Brazil Electronic Engineering Department Brazil Structural Engineering Department State University Rio de Janeiro Brazil Electrical Engineering Department Pontifical Catholic University Rio de Janeiro Brazil

ISBN: (纸本)9781905088201

Despite the multiple failure modes associated to bolted steel joints the block shear failure is frequently the controlling limit state of gusset plates, tension members and coped beam joints. The block shear rupture is characterised by a condition where a steel block area, nearby the holes of bolted joint region, reaches its maximum capacity dictated by a tension to shear interaction. If the joint is loaded beyond this limit a steel block is eventually separated from the main structure. Many models have been proposed to avoid shear block failure in steel design. These models incorporate a combination of the various hypotheses that control the structural rupture. In the majority of cases, it involves a combination of rupture and yielding in the tension and shear planes of the designed joint. Various design formula for this structural engineering problem were proposed all over the years but a closed solution has not yet been reached, due to the influence of several independent parameters. Many studies have already been carried out with the available experimental data, however, non negligible errors are still present in the current design formulae. The main objective of the present paper is to present a back propagation neural network evaluation of the block shear phenomenon. The main neural network input parameters were the geometrical and material variables that control the block shear design. The neural network output parameter was the block shear capacity. The neural network training was based on experimental results present in literature and adopted cross validation techniques to avoid the neural network overfitting. The neural network results were promising, with reduced associated errors and confirmed the possibility of using this methodology to generate trustworthy data. These new data, coupled with the existent experiments, can help the production of more accurate design formulae. © civil-Comp Press, 2007.

关键词： Neural networks

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Acoustic performance of closing panels used in steel-structured buildings

Acoustic performance of closing panels used in steel-structu...

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18th International Congress on Sound and Vibration 2011, ICSV 2011

作者： Ribas, Rovadávia A.J. Souza, Henor A. Civil Engineering Post-Graduate Program Universidade Federal de Ouro Preto Escola de Minas Campus Morro do Cruzeiro 35400-000 Ouro Preto - MG Brazil

ISBN: (纸本)9781618392596

In this research, it was made the evaluation of the acoustic performance of some closing systems mostly used in steel-structured buildings in Brazil, for instance walls made of the cement plates, precast concrete panels and plasterboard walls. The acoustic performance was evaluated by estimating the sound transmission loss that occurs through them using a simplified graphical method. It was studied the performance of these kinds of panels and their combinations forming double panels, with and without sound-absorbing material between them. Copyright © (2011) by the International Institute of Acoustics & Vibration.

关键词： Precast concrete

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