Artigos - Engenharia Civil e Ambiental - FEB

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Estimation of Toughness as a Function of Compression Strength Parallel to the Grain of Tropical Woods
(2023-01-01) Ruthes, Heloiza Candeia; Dos Santos, Herisson Ferreira; De Araujo, Victor Almeida [UNESP]; Azambuja, Maximiliano Dos Anjos [UNESP]; Aquino, Vinicius Borges de Moura; Chahud, Eduardo; Branco, Luiz Antônio Melgaço Nunes; Favarim, Higor Rogério [UNESP]; de Campos, Cristiane Inácio [UNESP]; Lahr, Francisco Antonio Rocco; Christoforo, André Luis; Universidade Federal de São Carlos (UFSCar); Universidade Estadual de Maringá (UEM); Universidade Estadual Paulista (UNESP); Federal University of Southern and Southeastern Pará; Universidade Federal de Minas Gerais (UFMG); Universidade de São Paulo (USP)
Tropical species are widely used in construction, and their physical and mechanical properties have been important characteristics with direct impact on the design of structures, especially the strength and stiffness of wood applied in them. Tests to obtain both parameters are conducted under ABNT NBR 7190 (1997) guidelines in Brazil, being rarely found in some research centers because of the higher costs of testing equipment. For instance, the toughness test depends on equipment with a pendulum, whose device requires accuracy and maintenance for reliable analyses. This paper aims to estimate toughness through another property more easily found, given by the compression strength parallel to the grain. For this, 20 tropical wood species of the South American region were used to obtain initial values of these properties. The characteristic values of the compression strength parallel to the grain as well as linear and quadratic regression models were obtained. Statistical analysis was performed and confirmed that a linear model gave better predictions than a quadratic model.
Identifying Collapsible Soils from Seismic Cone (SCPT): A Qualitative Approach
(2023-03-01) Rocha, Breno Padovezi; Silveira, Isabela Augusto [UNESP]; Rodrigues, Roger Augusto [UNESP]; Lodi, Paulo Cesar [UNESP]; Giacheti, Heraldo Luiz [UNESP]; Science and Technology of São Paulo (IFSP); Universidade Estadual Paulista (UNESP)
Collapsible soils are unsaturated low-density soils that undergo abrupt settlement when flooded without any increase in the in-situ stress level. The first stage of the site characterization is identifying collapsible soils, since these are problematic soils. Seismic cone testing (SCPT) has been increasingly used for site characterization, because it allows combining stratigraphic logging with the maximum shear modulus (G0) determination. In this paper, laboratory and in-situ tests carried out at 21 sites with collapsible and non-collapsible soils are interpreted to differentiate between such soils, based on the seismic cone test (SCPT). Collapsible soils have G0/qc values greater than 23 and qc1 values less than 70, while non-collapsible soils have G0/qc values less than 23 and qc1 values greater than 70. The investigated collapsible soils have microstructure (bonding/cementation), but the classical approach cannot be sufficient to identify collapsible soils alone. An approach was used to identify collapsible soils based on maximum shear modulus (G0), normalized cone resistance (qc1), and cone resistance (qc). The chart G0/qc versus qc1 and boundaries is an alternative for distinguishing between collapsible and non-collapsible soils in the early stage of site investigation. This qualitative approach should be used in the preliminary investigation phase to select potentially collapsible soils and helps guide the sampling of potentially collapsible soils for laboratory testing. Further SCPT data from different soil types, particularly the collapsible ones, are valuable to adjust or confirm the boundary equations suggested.
Suction Influence on Load–Settlement Curves Predicted by DMT in a Collapsible Sandy Soil
(2023-02-01) Saab, Alfredo Lopes [UNESP]; Rodrigues, André Luís de Carvalho [UNESP]; Rocha, Breno Padovezi; Rodrigues, Roger Augusto [UNESP]; Giacheti, Heraldo Luiz [UNESP]; Universidade Estadual Paulista (UNESP); Federal Institute of São Paulo
The plate load test (PLT) is the most reliable in situ testing for studying the load–settlement behaviour of footings on unsaturated collapsible soils. In these soils, the suction profile is not constant along the depth, and the scale effect between the prototype and footing leads to different suction averages and, consequently, different data. One method to eliminate the effect of soil suction on the test data is to fully saturate the soil prior to the test, which is also recommended at the design process for footing on collapsible soils. However, the inundation process on PLTs is expensive and time-consuming, which makes this procedure difficult to incorporate into engineering practice. This study presents a device that can be attached to flat dilatometer (DMT) to allow local inundation of the soil as part of the in situ test campaign and obtain the DMT-constrained modulus (MDMT) for both natural and inundated conditions. The MDMT presented an average reduction of 56% from natural to inundated condition. This parameter can be used in a model to predict load–settlement curves by DMT data considering the suction influence on this behaviour. The curves obtained from the prediction model were compared to curves determined by PLT conducted under the same in situ conditions. Good agreement was found between the curves predicted by DMT and those measured by PLT for both conditions. The proposed procedure, which uses a device attached to the DMT blade, provides an investigation method to obtain the load–settlement curve under different suction conditions, which can help in the selection and performance prediction of shallow foundations, taking into account suction and collapse phenomenon-related problems.
Sem título
(2023-03-01) Juarez, Mariana Barbosa [UNESP]; Mondelli, Giulliana [UNESP]; Giacheti, Heraldo Luiz [UNESP]; Universidade Estadual Paulista (UNESP)
Equations 10 and 11 should be interchanged. The Original article has been corrected.
An overview of in situ testing and geophysical methods to investigate municipal solid waste landfills
(2023-02-01) Juarez, Mariana Barbosa [UNESP]; Mondelli, Giulliana [UNESP]; Giacheti, Heraldo Luiz [UNESP]; Universidade Estadual Paulista (UNESP)
Municipal solid waste (MSW) management is challenging as a whole. Global waste generation is expected to continue to increase in the coming years, and landfills are currently the primary destination. Therefore, the stability of these structures must be carefully evaluated to prevent failures and associated health and pollution risks, which implies the determination of waste properties using more reliable approaches. This paper presents a scoping review of field data from MSW landfills and outlines suggestions for future work. Studies published in the past twenty years were selected following a systematic search process in databases. Aspects discussed include (1) strength parameters and soil behavior type from in situ testing, (2) elastic moduli from seismic wave propagation, and (3) moisture content from geoelectrical measurements. Although the values of geotechnical parameters have varied due to waste heterogeneity and applied methods, the trends observed with depth and age could be compared. Research opportunities involve the spatial analysis of mechanical properties at a given site, seismic response of landfills with high organic content and saturation degree, interpretation of long-term resistivity monitoring, and combination of electrical properties to assess the degradation stages within the waste mass.
Digital transformation in school management: the legacy that strategic actions in the 2020s leave for future pandemics
(2022-01-01) de Almeida Barbosa Franco, Jacqueline [UNESP]; Espuny, Maximilian [UNESP]; da Motta Reis, José Salvador [UNESP]; Diogo, Gabriel Miranda Monteiro [UNESP]; Paes, Luis Alberto Bertolucci [UNESP]; Costa, Ana Carolina Ferreira [UNESP]; Nunhes, Thaís Vieira [UNESP]; Barbosa, Luís César Ferreira Motta; Rodrigues, Andréia Marize [UNESP]; Battistelle, Rosane Aparecida Gomes [UNESP]; de Oliveira, Otávio José [UNESP]; Universidade Estadual Paulista (UNESP); Universidade do Estado do Rio de Janeiro (UERJ); Centro Federal de Educação Tecnológica Celso Suckow da Fonseca - CEFET-RJ
With the outbreak of social withdrawal due to the pandemic, many countries have undergone drastic transformations in various spheres. In education, face-to-face classes were transformed into distance learning. However, this sudden change caused several problems for students and teachers. Given these events, the purpose of this article was to propose exceptional actions to improve the transition from face-to-face classes to virtual classes. For this, the elements that positively and negatively impacted education in the Covid-19 pandemic were identified in the literature. These elements were then clustered into four strategies, these being: redesign of pedagogical practices, psychological and social support, technological infrastructure in virtual teaching, and school management to cope with the pandemic scenario. The multiple case study method was used, investigating five technical schools located in the state of São Paulo (Brazil). With this, it was possible to propose 10 exceptional actions aimed at the transition from face-to-face classes to virtual classes. The main novelty of this article was the proposition of actions to motivate the school community against the impacts of the pandemic, building memory in its agents, making them more prepared for unexpected events.
Geomechanical parameters in the active zone of an unsaturated tropical soil site via laboratory tests
(2022-10-01) Fernandes, Jeferson Brito [UNESP]; Saab, Alfredo Lopes [UNESP]; Rocha, Breno Padovezi; Rodrigues, Roger Augusto [UNESP]; Lodi, Paulo César [UNESP]; Giacheti, Heraldo Luiz [UNESP]; Universidade Estadual Paulista (UNESP); Instituto Federal de São Paulo
The seasonal variability of geotechnical parameters in the unsaturated zone is typically neglected in the design of geotechnical works. In most of the geotechnical projects the parameters are determined only for the saturated condition. Although it is known that this condition is the most critical to soil strength and deformability, this conservative approach may neglect a possible important contribution of the unsaturated condition, resulting in an increase in the cost of the geotechnical solution. This paper presents and discusses the site characterization of the active zone of an unsaturated sandy soil profile under different suction conditions. Laboratory tests with controlled suction (retention curves, triaxial compression with bender elements and oedometer tests) were carried out on undisturbed samples collected from 1.0 to 5.0 m depth. The results show that strength and deformability parameters are strongly affected by soil suction and are less influenced by confinement stress up to 5.0 m depth. All the investigated subsoil profile shows a collapsible behavior, more pronounced closer to the ground surface and under the effect of higher suction values. The findings highlight the importance of incorporating the suction influence in the site investigation, parameter determination, and geotechnical design for more economical, reliable, and environmentally sustainable solutions.
The importance of whole-core soil sampling (WCSS) for high-resolution site characterization
(2019-09-13) Riyis, Marcos Tanaka; Arakaki, Edson; Riyis, Mauro Tanaka; Giacheti, Heraldo Luiz [UNESP]; Centro Universitário SENAC; ECD Ambiental; Universidade Estadual Paulista (UNESP)
The traditional technique of contaminated site assessment in Brazil is based on the installation of 3 meters screen section monitoring wells (2 meters in saturated zone, and 1 meter in vadose zone), and soil sampling only in the vadose zone, performed in the same survey and with the same equipment used to monitoring well installation drilling (usually manual auger or mechanized hollow auger). This technique is not capable of providing enough information for an appropriate conceptual site model elaboration and is also incompatible with the following standards: NBR 16.434, NBR 15.495-1, ASTM D6282 and CETESB Board Decision 038 (DD-038). For these objectives to be fully achieved, it is necessary to prioritize, in site assessment, the use of whole-core soil sampling (ASPC), that collects representative samples of the full profile, including the saturated zone. The ASPC should allow: The acquisition of samples for chemical and physical analysis in the laboratory; conducting a vertical screening of contaminants; and the identification and characterization of the Hydrostratigraphic Units. For such proposal, it is necessary to use Direct Push technique, and within this technique, the Dual Tube, Piston Sampler, or in special cases, Cased Single Tube methods. Of these, the one that proved most efficient for the execution of the ASPC was the Dual Tube.
ARTIFICIAL NEURAL NETWORKS RESTRICTION FOR ROAD ACCIDENTS SEVERITY CLASSIFICATION IN UNBALANCED DATABASE
(2019-01-01) Chuerubim, Maria Lígia; Valejo, Alan; Bezerra, Barbara Stolte [UNESP]; da Silva, Irineu; Universidade Federal de Uberlândia (UFU); Universidade de São Paulo (USP); Universidade Estadual Paulista (UNESP)
The objective of this study is to discuss the main constraints in classifying the severity of road accidents using Artificial Neural Networks (ANN). To achieve this, ANN modelling with Multiple Layers Perceptron (MPL) was used. This method is recommended for treating non-linear problems, whose distributions are not normal, which is the case for road accidents. Variables associated with the characteristics of accidents, road infrastructure and environmental conditions were used, with the objective of identifying the influence of these factors in the accident severity. The results indicated that ANN modelling with MPL presents a potential association among the parameters related to road accidents. However, the results are limited, since the classification process provides a low rate of accuracy for accidents with victims. Such accidents correspond to less frequent observations in the database, meaning that the data is less represented, and the database becomes unbalanced. Thus, for further research studies, the use of ANN with MPL associated with data balancing methods is suggested, in order to obtain the best data fit to the model and more consistent and realistic results.
Factors affecting sanitation coverage in three income levels and potential toward achieving SDG 6.2
(2023-02-01) Bankole, Abayomi Oluwatobiloba [UNESP]; James, Abraham Olamilekan [UNESP]; Odjegba, Enovwo Erere; Bankole, Afolashade Racheal [UNESP]; Emmanuel, Babajide I. [UNESP]; Fiore, Fabiana A. [UNESP]; Pu, Jaan H.; Moruzzi, Rodrigo [UNESP]; Universidade Estadual Paulista (UNESP); Federal University of Agriculture; University of Bradford
An equitable sanitation coverage promotes sustainability, economic prosperity, and public health protection. This study examined factors affecting sanitation coverage and the potential of selected countries across three income levels (Low-Income, Lower-Middle, and Upper-Middle Income Countries) to meet Sustainable Development Goal 6.2 by developing a Sanitation Coverage Index (SCI). Nine developing countries were selected based on the following sets of criteria: income level, population, and geographical region. Twenty years (2000-2020) of sanitation coverage data were extracted from the JMP database and visualized. The SCI was developed using the service level criteria and examined the local drivers of poor sanitation coverage. Findings show that all countries studied made good progress and have commendable current status, except Ethiopia, Rwanda, and Nigeria. Nigeria has the highest open defecation coverage and may not meet the 2030 target. The SCI result shows that Turkey, Ukraine, and China have excellent coverage (scoring: 44, 43, and 40). Brazil, Bangladesh, and DPR Korea have satisfactory performances (36, 31, and 31), while Nigeria, Rwanda, and Ethiopia recorded unsatisfactory progress (28, 27, and 16). The strongest factors influencing poor coverage include population, high socioeconomic inequalities, and socio-political challenges. Therefore, the institutionalization of minimum acceptable standards, adequate sensitization, and funding could improve sanitation coverage in the countries assessed.
ABD: A machine intelligent-based algal bloom detector for remote sensing images[Formula presented]
(2023-03-01) Ananias, Pedro Henrique M. [UNESP]; Negri, Rogério G. [UNESP]; Bressane, Adriano [UNESP]; Colnago, Marilaine [UNESP]; Casaca, Wallace [UNESP]; Universidade Estadual Paulista (UNESP)
This paper presents a new approach for detecting algal insurgence in water environments by using remote sensing image series. The designed methodology provides a robust and accurate algorithm as an alternative to typical algal bloom detection methods. In more technical terms, by only assuming as input an image time series, a fully automatic data-driven scheme involving pre-processing and feature extraction procedures is derived, which models a machine intelligent-based classifier capable of detecting algal blooms. Lastly, algal insurgence maps are then produced by passing to the classifier an image taken at an instant of interest.
Prioritization of key indicators for the classification of successional stages in regenerating subtropical Atlantic forest, Southern Brazil: a proposal based on multivariate order statistics
(2023-06-01) Bressane, Adriano; Siminski, Alexandre; Gomes, Isadora Gurjon; Melo, Carrie Peres [UNESP]; da Rosa, Graziele Coraline Scofano [UNESP]; dos Santos Galvão, Amanda Louisi [UNESP]; Silva, Mirela Beatriz [UNESP]; de Castro Medeiros, Líliam César; Negri, Rogério Galante; Environmental Engineering Department; Universidade Federal de Santa Catarina (UFSC); Universidade Estadual Paulista (UNESP)
Statement of problem. Brazilian guidelines establish a set of parameters to classify forest regeneration stages, but there are no criteria or evidence for prioritizing key indicators. Purpose. This study performed a comparative analysis between phytosociological parameters to verify the hypothesis that there is a difference in their explanatory power of the forest regeneration stages. Consequently, it shows the need to prioritize key indicators for classifying forest regeneration stages. Material and methods. The analyzes were carried out using a database of the Floristic Forest Inventory of Santa Catarina, Southern Brazil, composed of 177 sampling units of subtropical Atlantic forest (Mixed Ombrophilous Forest) characterized according to 12 quantitative and qualitative phytosociological parameters. Several statistical tests were performed to analyze the explanatory ability of the phytosociological parameters. Such process includes tests for multivariate ordering, principal component analysis (PCA), discriminant analysis (FDA and QDA), exploratory factor analysis (EFA), and multiple correspondence analysis (MCA). Afterward, is provided a ranking regarding the analyzed indicators based on their usefulness to separate forest regeneration stages, measured in terms of classification accuracy according to the QUEST (Quick Unbiased Efficient Statistical) algorithm. The hypothesis was verified with two-way tests at a significance level (α) equal to 0.05, for a test power (1-β) of 0.8 and a minimum detectable effect of medium size (ρ = 0.3). Results. Statistical significance tests confirmed the research hypothesis. Regarding both the qualitative and quantitative variables, the ranking resulting from the discriminant analysis provided the best accuracy (85.3%). In decreasing priority order, was defined the following parameter order: basal area, number of individuals and species, Shannon diversity index, diameter at breast height, total height, stem height, leaf litter, canopy structure, canopy cover, the density of lianas and epiphytes. Conclusions. The phytosociological parameters have statistically different explanatory power (p < 0.0001), which should be considered when classifying forest regeneration stages. Practical implications. The presented results and conclusions should substantially impact the guidelines and decision-making process for cutting down the forest/native vegetation and applicable compensation measures, which are currently only based on the forest regeneration stages.
Evaluation of groundwater suitability in the Cretaceous Abeokuta Formation, Nigeria: Implications for water supply and public health
(2022-11-01) Bankole, Abayomi Oluwatobiloba [UNESP]; Oluwasanya, Grace; Odjegba, Enovwo E.; Federal University of Agriculture; Universidade Estadual Paulista (UNESP)
The health implications of exposure to chemicals like cadmium and lead through the consumption of polluted groundwater have made monitoring groundwater sources imperative. This study evaluated the suitability of groundwater sources over the Cretaceous Abeokuta Formation, Ogun State, Nigeria, and mapped the distribution to identify the major pollution source. Abeokuta Formation was sectionalized into three regions (western, central, and eastern) to sample one hundred and seven groundwater sources. In-situ and detailed laboratory testing for physicochemical, anion, cation, metals and E-coli were carried out following the APHA standard procedure. Laboratory results were subjected to Water Quality Index (WQI), carcinogenic and non-carcinogenic risks of metals, spatial analysis using Kriging interpolation of ArcGIS, and several plots. Findings showed that the percentage of samples with a problematic pH concentration, chloride, bicarbonate, iron, lead, cadmium and coliform increased from western to central and recorded the highest percentage in the eastern region. Hydrogeochemical charts inferred that carbonate and silicate weathering were responsible for the enrichment of anions in the aquifer. WQI result indicates that all samples are within the acceptable range (<100). Although cancer risks for all samples were insignificant, 26.7%, 23.4%, and 56.7% of samples have significant non-carcinogenic risks (HI > 1) in western, central and eastern regions, respectively. Spatial analysis showed that the low elevation areas in the central and eastern regions have high non-cancer risks. The contribution of parameters to non-cancer risks were Cd > Cu > Pb > Zn > Fe > NO3− > Cr > Ni in central, and Cu > Cd > Pb > Zn > Fe > NO3− > Cr > Ni in eastern regions. This study, therefore, established that geogenic processes have severely polluted the groundwater aquifer in the eastern region, and groundwater in the area is unsuitable for consumption and poses a severe public health concern.
Applying geoprocessing resources in the declivity analysis of the cycling network of the city of São Paulo
(2019-01-01) Simeão, João Vitor Penteado [UNESP]; Manzato, Gustavo Garcia [UNESP]; Viviani, Eliane; Universidade Estadual Paulista (UNESP); Universidade Federal de São Carlos (UFSCar)
The huge fleet of vehicles causes environmental impacts, congestion and affects urban mobility and the quality of life of the population. In this context, sustainable urban mobility suggests the use of non-motorized modes as a way to change this reality. Bicycles are an example: they are versatile and non-polluting. The incentive for its use focuses on governmental measures, which include the provision of infrastructure and adequate physical conditions, such as declivity. Several technical guides indicate that slopes above 5% should be avoided because they are difficult for cyclists on the way up and can lead to high speeds in descending ways. In order to investigate the real condition of a cycling network in terms of its declivity, the cycling network of the city of São Paulo was studied. Using geoprocessing resources, two strategies were applied: the first one focused on the intersection of the cycling network vector database and a declivity map; and the second one on the generation of a digital elevation model using contour lines and subsequent assignment of altimetric information to the cycling network. The results obtained with the first strategy indicated 47% of the São Paulo’s cycling network comprises links whose slopes are above 5%. On the other hand, the analyses with the contour lines revealed that 17,9% of the cycling network has slopes above 5%. The concluded was that the most part of the cycling network is composed by routes with adequate declivities, which should not result in major difficulties for cyclists.
Shear strength of municipal solid waste rejected from material recovery facilities in the city of São Paulo, Brazil
(Associação Brasileira de Mecânica dos Solos, 2023-05-15) Juarez, Mariana Barbosa [UNESP]; Mondelli, Giulliana [UNESP]; Giacheti, Heraldo Luiz [UNESP]; Universidade Estadual Paulista (UNESP)
The mechanical behavior of municipal solid waste (MSW) is a critical issue in environmental geotechnics, given the pollution and public health risks associated with slope failures. In Brazil, waste composition is expected to change due to the hierarchy of sustainable practices established by the National Solid Waste Policy, which aims to improve the recovery of organic and recyclable materials. Not much progress has been made since the implementation of this law; thus, its effects on the design and operation of landfills are not fully clear. This study presents and discusses compaction and shear strength parameters of dry MSW after mechanical sorting of medium and large recyclable items and shredding. The maximum dry unit weight for the standard Proctor compaction test ranged from 6.6 to 10.0 kN/m3 and the optimum moisture content ranged from 20% to 42%. Stress-displacement curves of direct shear tests showed strain hardening and shear strength parameters of Mohr-Coulomb envelopes were displacement-dependent. The friction angle ranged from 3.2° to 42.9° and the cohesion intercept ranged from 1.3 to 31.3 kPa, at a displacement of 9 mm (15% of the specimen length). These results are in line with the literature, since a high content of waste materials that proved to affect geotechnical properties, such as plastic, paper, cardboard, textile, and glass, remained after pre-treatment.
Maximum shear modulus and modulus degradation curves of an unsaturated tropical soil
(Associação Brasileira de Mecânica dos Solos, 2023-04-28) Fernandes, Jeferson Brito [UNESP]; Rocha, Breno Padovezi; Giacheti, Heraldo Luiz [UNESP]; Universidade Estadual Paulista (UNESP); Instituto Federal de Educação, Ciência e Tecnologia de São Paulo
The maximum shear modulus (G0) and the modulus degradation curve (G/G0 versus γ) are important information in the evaluation of the soil mechanical behavior, both for dynamic and static loads. Dynamic tests (resonant column and cyclic triaxial tests) are not routinely performed in geotechnical practice in Brazil, and the geotechnical literature on the dynamic behavior of unsaturated tropical soils is limited. This paper presents and discusses seismic dilatometer (SDMT), resonant column, and triaxial test with bender elements and internal instrumentation to determine G0 and the modulus degradation curve in an unsaturated tropical sandy soil profile. It was observed that G0 tends to increase non-linearly with soil suction and net stress (σ - ua). It was also observed that the in situ G0 values determined with the SDMT were higher than those from laboratory tests (bender elements and resonant column). The modulus degradation curves determined with resonant column were used to define the reference curve via SDMT for the studied site. Soil suction influence in shear modulus degradation curves determined with unsaturated triaxial compression tests with local instrumentation is also presented and discussed.
Numerical simulation of punching shear failure in recycled aggregate concrete slabs with steel fiber reinforcement
(IBRACON - Instituto Brasileiro do Concreto, 2023-05-22) Siqueira, Alana Helena Cara [UNESP]; Gimenes, Marcela [UNESP]; Manzoli, Osvaldo Luís [UNESP]; Rodrigues, Eduardo Alexandre [UNESP]; Universidade Estadual Paulista (UNESP)
The use of construction waste as aggregate in the production of concrete is becoming a more frequent alternative due to the advantages associated with the sustainability aspect. Results obtained in experimental tests with recycled aggregate concrete suggest that mechanical properties such as elastic modulus, compressive, tensile and flexural strength tend to reduce with partial or total replacement of natural aggregate by recycled one. On the other hand, the use of steel fiber reinforcement can minimize the reduction of these properties, since the fibers tend to improve the material strength and ductility. This work proposes a numerical approach, seeking to better predict and understand the structural mechanical behaviors and failure patterns of reinforced recycled aggregate concrete slabs with and without steel fiber. Based on the finite element method, an appropriated constitutive damage model is employed to represent the nonlinear behavior of the conventional/recycled concrete, while an elastic-perfectly plastic model is used to describe the mechanical behavior of the reinforcements. To couple the independent FE meshes and incorporate the mutual interaction between the different components, rigid and non-rigid coupling technique is used to represent the perfect adherence or the bond-slip behavior. Seven concrete slabs were numerically analyzed either with different percentages of recycled aggregate replacement (0, 50 and 100%) or steel fibers content (0.0, 0.5 and 1.0%) and the results were compared with the experimental ones. The results showed that the applied methodology is capable of simulating with good accuracy the punching shear failure mechanism of the slabs. It was observed that the punching ultimate load decreased with increase of recycled aggregate content, as well as that the steel fiber addition can minimize the negative effects of recycled aggregate employment.
UV light device for vertical screening of soil samples contaminated with LNAPL
(2022-09-01) Arakaki, Edson; Nagata, Daniel Takenori; Riyis, Marcos Tanaka; Giacheti, Heraldo Luiz [UNESP]; Centro Universitário SENAC; Universidade Estadual Paulista (UNESP)
Petroleum hydrocarbons in light nonaqueous-phase liquid (LNAPL) can cause significant contamination when released into the environment. The identification, delineation, and understanding of their interactions with hydrostratigraphic media are essential for geoenvironmental site characterizations. Investigations of LNAPL-contaminated sites in Brazil are mostly conducted using monitoring wells, which have limitations in identifying LNAPL. Site characterization techniques based on ultraviolet light (UV) emissions, which are commercially known as Ultraviolet Optical Screening Tool (UVOST) and Optical Image Profiler (OIP), are more effective in identifying and providing qualitative LNAPL data. A bench testing campaign was conducted to evaluate the performance of an alternative, low-cost UV light device for determining the presence of LNAPL contamination in soil samples. This device creates a dark environment and uses UV light at different wavelengths combined with filters with different colors. Three different soils (e.g., organic, fine-medium sand, and well-sorted medium sand), three petroleum hydrocarbon products (e.g., lubricating oil, gasoline, and diesel) and deionized water were used. A total of 54 bench tests were conducted for hydrocarbon detection to assess the applicability of the alternative, low-cost UV light device. A UV-C light with a red filter produced the best results for identifying soil contamination. It was found that the UV light device is more efficient when using different wavelengths that are associated with more than one color filter. The application of this system has been broadened as it has now become more efficient when used with different combinations of soil types and LNAPL sources.
Unfolding research themes for industrial symbiosis and underlying theories
(2022-01-01) Agudo, Fabiana Liar [UNESP]; Bezerra, Barbara Stolte [UNESP]; Gobbo, José Alcides [UNESP]; Paes, Luis Alberto Bertolucci [UNESP]; Universidade Estadual Paulista (UNESP); Science and Technology of Sao Paulo
This paper aims to analyze the research themes that are addressed in studies on industrial symbiosis (IS), from the perspective of theories. The paper method is a longitudinal analysis of retrospective nature from 1998 to 2021. This approach allowed to detects the main drivers and associated themes that structured researches on IS in the period. In general, Industrial Ecology Theory, Network Theory, Systems Theory and Organizational Theory were present in a considerable part of research themes on IS. It was observed that the IS research themes moved over the period analyzed to nine areas of study: (1) Waste as a resource, (2) development industrial symbiosis network, (3) circular economy and industrial symbiosis, (4) industrial co-localization, (5) energy innovations, (6) closed loop chains, (7) IS's social aspects, (8) regional-level metabolism, and (9) waste knowledge. In summary, the contributions of this paper are the thematic proposition of IS from the perspective of theories, pointing out the key-aspects; and presentation of a research themes' diagram towards the IS buildup.
Reliability-Based Topology Optimization: An Extension of the SESO and SERA Methods for Three-Dimensional Structures
(2022-05-01) Simonetti, Hélio Luiz; Almeida, Valério Silva; Das Neves, Francisco de Assis; Almeida, Vírgil Del Duca; Neto, Luttgardes de Oliveira [UNESP]; Federal Institute of Minas Gerais (IFMG); Universidade de São Paulo (USP); Federal University of Ouro Preto (UFOP); Universidade Estadual Paulista (UNESP)
This study takes an approach to reliability-based topology optimization (RBTO) for 3D structures by applying an expansion of smoothing evolutionary structural optimization (SESO) and sequential element rejection and admission (SERA) for three-dimensional optimization. In the search for the stable optimal solution, and a more reliable structure, we present a performance index with the ability to monitor the evolutionary optimization procedure and adopt the filtering scheme usually applied in solid isotropic material with penalization (SIMP). The limit state functions are the maximum displacement constraints imposed in the topology optimization procedure and a structure’s performance control; a comparative analysis of the deterministic topology optimization (DTO) with the RBTO models is also explored. The obtained results suggest the importance of using the RBTO concept in 3D structures as part of the design analysis process.

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