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  • ItemArtigo
    New insights on understanding the Portland cement hydration using electrical impedance spectroscopy
    (2023-12-01) Bortolleto, Marcelo ; Sanches, Alex Otávio ; Santos, Josiane Alexandrino ; Tashima, Mauro M. ; Payá, J. ; Soriano, L. ; Borrachero, M. V. ; Malmonge, José Antônio ; Akasaki, Jorge Luiz
    This study aimed to bring new perspectives and understandings, as well as to elucidate the behavior of Portland cement hydration through electrical conductivity curves obtained by impedance spectroscopy (IS). The IS measurement was performed on Portland cement paste with w/c ratio of 0.40 up to 28 curing days. According to the results, based on the inflection points of its respective derivative, the electrical conductivity curve of Portland cement paste can be subdivided into eight different regions. A new region (region IV) in the acceleration period, characterized by the resume of dissolution reactions and microstructure formation with the paste in a semi-fluid state, was established. Moreover, a shoulder observed in region VI was attributed to the formation of AFt phases from the reduction of CaSO4, and secondary reactions of ionic release in the pore network. Hence, new insights on the electrical conductivity curve of Portland cement paste are reported confirming the IS as a sensitive and promising technique.
  • ItemArtigo
    Critical analysis of the mechanical properties of Dinizia excelsa wood in relation to moisture variations: implications for ABNT NBR 7190:2022
    (2024-01) Fraga, Iuri Fazolin ; Arroyo, Felipe Nascimento ; Mascarenhas, Fernando Junior Resende ; Ruthes, Heloiza Candeia ; Soares, Larissa Soriani Zanini RIbeiro ; Aquino, Vinicius Borges de Moura ; Christoforo, Andre Luis ; Lahr, Francisco Antonio Rocco
    Brazil possesses an extensive forested territory conducive to the prevalence of numerous tree species, including Dinizia excelsa, commonly known as Angelim-Vermelho. The utilization of a wood species in a structural system necessitates a comprehensive analysis of its physical-mechanical properties. In this context, a crucial variable for study is the moisture content, the variations of which, a priori, can significantly impact wood properties. Although the Brazilian code prescribes specific models to adjust strength and stiffness concerning the reference mois-ture, allowing a linear increase as moisture content decreases, this phenomenon may not universally apply to all wood species. Some species may exhibit statisti-cally constant or even decreased values, contradicting code predictions. There-fore, by employing analysis of variance (ANOVA) at a 5% significance level, this research aims to examine the impact of moisture content variation (ranging from 12% to the fiber saturation point – FSP) on 12 mechanical properties of Dinizia excelsa wood. Each type of test involved the creation of 12 specimens, totaling 360 determinations. Among the 12 mechanical properties examined, four showed no significant variations between 12% moisture and the FSP. This suggests that the code formulation inadequately addresses all properties for all wood species. Furthermore, the study revealed that correction models can result in strength val-ues higher than experimentally obtained, thus overestimating structural capaci-ties, and compromising safety. Therefore, a critical reassessment of the existing Brazilian code is imperative.
  • ItemArtigo
    Influence of Sugar Cane Straw Ash in Mechanical and Microstructural Characteristics of Alkali-Activated Materials Based on Red Clay Brick Waste
    (2023-04-01) Bittencourt Batista, João Pedro ; Bassan De Moraes, Maria Júlia ; Mitsuuchi Tashima, Mauro ; Akasaki, Jorge Luís ; Payá, Jordi ; Bassan De Moraes, João Claudio ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP) ; Universitat Politècnica de València ; Instituto Tecnológico de Aeronáutica
    The present paper aims to assess the feasibility of using two wastes, sugar cane straw ash (SCSA) and red clay brick waste (RCBW), in the production of a new sustainable binder for alkali-activated materials (AAM). The RCBW/SCSA mass proportions assessed were 100/0, 87.5/12.5, 75/25, 62.5/37.5, and 50/50. The activating solution was composed of NaOH and sodium silicate with a Na+ concentration of 8.3 mol.kg-1 and a SiO2/Na2O molar ratio of 1.3. Moreover, 5 wt.% of calcium hydroxide was added. Compressive strength, the volume of permeable pore space, water absorption of mortars, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy with energy-dispersive X-ray spectroscopy of pastes were carried out in this study. Tests were carried out at 3, 7, and 28 days of curing at 25°C and 1 and 3 days at 65°C. Results showed that the mortars produced with RCBW/SCSA mass proportion of 50/50 presented an increase of 50% in compressive strength compared to samples with only RCBW (100/0) after 28 days of curing at 25°C (39.2 and 26.2 MPa, respectively). Moreover, the presence of SCSA content increases pore refinement and reduces water absorption. Studies on pastes showed that the SCSA favored the formation of N-A-S-H gels with higher silicon content and denser microstructure than the sample with only RCBW. Therefore, it can be concluded that the SCSA can be employed with RCBW in AAM to improve its mechanical properties and generate a denser structure.
  • ItemArtigo
    Life cycle assessment of lattice girder slabs with tire rubber residue addition
    (2022-01-01) Sampaio, Daniel Oliveira de Azevedo ; Rufato, Thássia Dias Zanardo ; Assunção, Camila Cassola ; Tashima, Mauro Mitsuuchi ; Akasaki, Jorge Luís ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP)
    The Life Cycle Assessment (LCA) has gained notoriety as a tool for analyzing the environmental impacts of products and services, standing out for analyzing all processes involved in production, from raw material extraction to final disposal, and enabling the preference for more environmentally sustainable materials and processes. This project evaluated and compared the environmental impacts of two concrete traces used in lattice precast slabs, one using tire rubber residue to partially replace sand, while the other uses only sand. The method used for the Life Cycle Impact Assessment (LCIA) phase was CML2001, and a sensitivity analysis was performed using the ReCiPe method. The slab made of concrete containing tire rubber residue generated, on average, 5% more emissions in all impact categories analyzed, being the production of CP II Z 32 cement the most critical process. The change in the LCIA method did not alter the conclusions obtained for the assessed impact categories.
  • ItemArtigo
    Development of water quality index as a tool for urban water resources management
    (2023-02-01) Bega, João Miguel Merces ; Albertin, Liliane Lazzari ; de Oliveira, Jefferson Nascimento ; Universidade de São Paulo (USP) ; Universidade Estadual Paulista (UNESP)
    Urban stream monitoring programs rarely consider the daily cycle of water quality. Furthermore, water quality indexes (WQIs) often rely on an excessive number of correlated parameters. To the best of our knowledge, no previous study used both the principal component analysis (PCA) and the daily cycle of the water quality of urban streams to create better WQIs. In this context, the present study aimed to develop a novel urban WQI (WQIurban) considering these two factors. Moreover, the main WQI in Brazil for water quality assessment for public supply (WQIcetesb) was used as a starting point (parameters: total solids (TS), temperature, turbidity, biochemical oxygen demand, pH, dissolved oxygen (DO), total nitrogen, total phosphorus, and thermotolerant coliforms (Escherichia coli)). The selected parameters to integrate the WQIurban received weights according to their importance for the conformation of water quality and a quality value was assigned to each parameter as a function of its concentration or measure. The developed WQIurban (parameters: pH, TS, E. coli, and DO) was able to maintain the seasonal and daily patterns of the urban stream water quality compared to the WQIcetesb. Nevertheless, the spatial relationship among the sampling sites was somewhat lacking. Our findings can help environmental managers, policy planners, and local researchers to improve their urban stream monitoring programs, saving money, time, and resources. Moreover, the WQIurban can be helpful during exceptional circumstances in which the water quality of urban streams must be quickly assessed.
  • ItemArtigo
    Spatial and Temporal Variability of Groundwater Quality Parameters in the Bauru Aquifer System (São Paulo State, Brazil)
    (2023-01-01) Lobo, Isadora Vitali ; Tercini, Olavo Tozete ; Di Lollo, José Augusto ; da Rocha Lima, César Gustavo ; Universidade Estadual Paulista (UNESP)
    Chemical substances can be harmful to humans when present in water at concentrations above the limits permitted by legislation. The present study analyzes the spatial-temporal variability of barium, chromium, nitrate and vanadium concentrations in groundwaters of the Bauru Aquifer System (BAS). For this purpose, triennial water-quality monitoring data (2016-2018) were acquired from CETESB (São Paulo Environmental Company). Descriptive statistical methods and geostatistical techniques (kriging) were applied. Results attest the spatial dependence of the water-quality parameters along time. Variograms indicate spatial determination coefficients (R2) between 0.435 and 0.961. The municipality of Presidente Prudente has the worst scenario, with estimates chromium and vanadium above the Maximum Allowed Values (MAV). The fact that most of licensed wells exploit water for urban supply makes the results worrying and shows up that public agencies must take some actions to decrease these concentrations.
  • ItemArtigo
    Hydrophobization and odorization of wood for use in civil construction by immersion in nanoemulsions of tea tree and copaiba essential oil
    (2022-01-01) de Lima Oliveira Paixão, Giovanna ; Filho, Adhemar Watanuki ; Bonfim, Kely Silveira ; Aouada, Fauze Ahmad ; de Moura, Marcia Regina ; Universidade Estadual Paulista (UNESP) ; Ciência e Tecnologia de São Paulo-IFSP
    Wood is a raw material from renewable source widely used by the construction industry due to its characteristics of easy handling and processability, good mechanical properties, sustainability, among others. Since it is a vegetal material, it is necessary to perform a preservative treatment before its application in civil construction. In this context, the search for new solutions as an option for biodegradable surface treatment to ensure the improvement of wood properties is one of the needs to be addressed so that the material performs well and increases its durability. Thus, treatments by immersion in emulsions of essential oils (EO) in the material, as an alternative to mitigate the occurrence of common pathologies in wood, proves to be a potentially innovative option for the furniture and construction industries. The present study aimed to evaluate the effects of hydrophobing and wood odorization treatments after the insertion of essential oils in nanoemul-sion, emulsion, and pure oil conditions. The essential oils used were melaleuca (Melaleuca alternifolia) and copaiba (Co-paifera officinalis), due to their antimicrobial, antifungal, antiseptic properties, and characteristic odor. The immersion application on the wood samples was conducted under the following conditions: 25% (w/w) melaleuca EO emulsion; 25% (w/w) copaiba EO emulsion; 2% (w/w) melaleuca EO nanoemulsion; 2% (w/w) copaiba EO nanoemulsion and the application of the same pure oils. The results showed that the suspension that presented the highest retention was the nanoemulsion, being OE of copaiba 44.10% and OE of melaleuca 40.41% in relation to the mass of the untreated sample. The emulsions resulted in 21.32% for OE copaiba and 20.51% for OE melaleuca, and in the pure oil condition, the observed retention was 15.11% for melaleuca OE and 23.82% for OE copaiba. The results obtained may be related to the hydrophilic characteristic of the wood, and the most aqueous suspension was the most absorbed. Through the Scanning Electron Microscopy (SEM) test it was possible to identify a uniform coverage of the samples for the pure oil, a rough aspect of coverage for the emulsion and a more cracked and dried surface in the samples with nanoemulsion. The contact angle test did not show a significant increase in hydrophobicity of the samples, with positive results from 7°±9° to 23°±15°, and in the nanoemulsion condition it decreased 12°± 9° compared to the untreated sample for copaiba EO and 16°± 9° for melaleuca EO, indicating a higher water permeability.
  • ItemArtigo
    Using the SWAT model to identify erosion prone areas and to estimate soil loss and sediment transport in Mogi Guaçu River basin in Sao Paulo State, Brazil
    (2023-03-01) dos Santos, Franciane Mendonça ; de Souza Pelinson, Natália ; de Oliveira, Rodrigo Proença ; Di Lollo, José Augusto ; Faculty of Sciences of the University of Lisbon ; Universidade Federal de Mato Grosso do Sul (UFMS) ; Universidade de Lisboa ; Universidade Estadual Paulista (UNESP)
    Water-driven erosion associated with the transport and deposition of sediments in watersheds may lead to contamination problems causing significant damage to land and infrastructure. The key factors that influence erosive processes are well known and include the precipitation rate, terrain topography, soil type, and vegetation cover. The soil and water assessment tool (SWAT) considers these factors and may be used to identify areas susceptible to soil erosion and to estimate soil loss and sediment transport and deposition. To corroborate this assumption, real data on rill erosion and sediment transport from the Mogi Guaçu River Basin in southeastern Brazil were used to validate SWAT estimates. The study shows that the model is able to identify soil-eroded areas and replicate the scale and variation patterns of sediment production, although not with great precision. Hence, it can successfully be used for prioritizing areas that require action and for evaluating alternative soil management and conservation practices to mitigate erosive processes.
  • ItemArtigo
    Effect of Aggregates Packing with the Maximum Density Methodology in Pervious Concrete
    (Mdpi, 2023-03-01) Arcolezi, Karina H. ; Silva, Rodrigo G. da ; Soriano, Lourdes ; Borrachero, Maria V. ; Monzo, Jose ; Paya, Jordi ; Tashima, Mauro M. ; Akasaki, Jorge Luis ; Universidade Estadual Paulista (UNESP) ; Univ Politecn Valencia
    The granulometric distribution of the aggregates used in pervious concrete can significantly impact its mechanical and hydraulic properties by modifying granular skeleton and pore distribution. The unit weight increases when single-sized aggregates are combined, which results in improved mechanical properties. In this study, the maximum density methodology was applied to enhance pervious concrete's mechanical strength by using three narrow-sized basaltic aggregates and their combination. The experimental results showed that the mechanical performance of the samples created with packed aggregates improved compressive strength by up to 81.2% and the energy support impact was higher than 225 J (50% higher than the reference sample) after curing for 28 days. Although the densification of packing aggregates increased, the greatest reduction in porosity was 24.3%. The lowest infiltration rate was 0.43 cm/s, a satisfactory value according to the literature. These findings suggest that the aggregates packing methodology is effective in producing optimized and sustainable pervious concretes.
  • ItemArtigo
    COMPARATIVE STUDY OF PARTICLEBOARDS WITH HEVEA BRASILIENSIS WASTE FROM DIFFERENT PRODUCTION AND MOISTURE CONFIGURATIONS
    (Slovak Forest Products Research Inst, 2022-01-01) Souza, Matheus Viana de ; Cazella, Pedro Henrique da silva ; Da Silva, Sergio Augusto Mello ; Rodrigues, Felipe Reis ; Herradon, Marjorie Perosso ; Da Costa, Fabiola Medeiros ; Aouada, Marcia Regina De Moura ; Aouada, Fauze Ahmad ; Santos, Herisson Ferreira dos ; Pinto, Edna Moura ; Araujo, Victor Almeida de ; Christoforo, Andre Luis ; Pinheiro, Roberto Vasconcelos ; Universidade Estadual Paulista (UNESP) ; Universidade Estadual de Maringá (UEM) ; Univ Fed Rio Grande do Norte ; Universidade Federal de São Carlos (UFSCar) ; MATO Grosso State Univ
    After the production cycle of latex, Hevea brasiliensis trees become residual living plants for this activity, although their woody trunks are still potentially subject to industrial utilization. Bio-composites derived from rubberwood particles were manufactured using two different configurations as a strategy to examine the potential of this species with respect to mechanical behavior. Homogeneous panels were developed from particles at the saturation condition, and heterogeneous panels were obtained from dry particles conditioned at 12% moisture content. Both examples were heat-pressed and glued with castor oil-based polyurethane resin. Density, short-term water absorption and thickness swelling, modulus of rupture and modulus of elasticity in the static bending and perpendicular tensile were evaluated. Panels derived from rubberwood particles proved to be viable according to the technical standards.
  • ItemArtigo
    Reinforcement of Timber Beams with Steel Bars: Parametric Analysis Using the Finite Element Method
    (2022-07-01) Christoforo, André Luis ; Gomes, Arthur Filipe Freire ; Arroyo, Felipe Nascimento ; Mascarenhas, Fernando Júnior Resende ; Santos, Herisson Ferreira dos ; Topolniak, Luciano ; Akasaki, Jorge Luis ; Universidade Federal de São Carlos (UFSCar) ; Federal Institute of Education Science and Technology of Rondônia ; Universidade Estadual Paulista (UNESP)
    Incorporating steel bars as reinforcement in glued laminated timber beams is a technique that aims at better structural performance, allowing the reduction of cross-sections. In the present research, based on experimental results from literature about the reinforcement of timbers beams, a parametric study was carried out with the aid of 164 numerical simulations performed within the scope of linear and nonlinear physical analysis via the finite element method to evaluate, with the aid of analysis of variance (ANOVA), the span, base, height, and the reinforcement ratio influence in the service force, ultimate force, and ultimate displacement. Multiple regression models evaluated by ANOVA were established to estimate the service and ultimate forces and ultimate and service displacements as a function of other variables. The results showed an average increase in the service load of 32% and 49%, and the ultimate load of 42.90% and 66.90%, for reinforcement rates of 2% and 4%, respectively. Regarding the multiple regression models, due to the good values obtained from the adjusted determination coefficients to estimate the values of the forces and the ultimate displacements, these can be used in the pre-design of glued laminated timber beams reinforced with steel bars.
  • ItemArtigo
    Analysis of water performance of coating mortars incorporated with tire rubber
    (2022-01-01) Pagoto, Leticia Martelo ; Akasaki, Jorge Luis ; Melges, José Luiz Pinheiro ; Fioriti, Cesar Fabiano ; Universidade Estadual Paulista (UNESP)
    This paper analyzed the behavior of mixed mortars incorporated with rubber from the tire retreading process, based on partial sand substitution. The content of rubber incorporation in the mortars was 5%, 10%, 15%, and 20% by volume. The different granulometries of rubber were denominated as thick (passed through a sieve # 1.19 mm) and fine (passed through a sieve # 0.60 mm). Tests were performed to evaluate water retention, capillary absorption, drying, immersion absorption, water vapor permeability, and permeability to water under pressure. The results showed that the fine rubber was distinguished by its higher retention of water at the contents of 15% and 20%, lower absorption via both capillary and immersion, higher drying capacity, higher permeability to water vapor, and lower permeability to water under pressure.
  • ItemArtigo
    Influence of mixing energy and pre-shear on the rheological characterization of cement pastes
    (2022-01-01) Campos, Renan Serralvo ; Caetano, Helmer Murra ; Maciel, Geraldo de Freitas ; Universidade Estadual Paulista (UNESP)
    The analysis of rheological behavior can encompass different materials, including cementitious materials, such as pastes, mortars and concretes, which, in fresh state, behave like fluids. In general, the quality control of these materials in fresh state is carried out through empirical tests that aim to qualify properties such as consistency, fluidity, among others. However, empirical tests are not able to completely characterize the rheological behavior of cementitious materials, being necessary for this to carry out rheometric tests, in which it is possible to obtain the fundamental rheological parameters – viscosity and yield stress – of these composites. Rheological characterization of cementitious materials involves the determination of rheological parameters of complex suspensions, composed of different constituent materials that interact with each other, from a chemical and physical point of view. Other factors, such as equipment geometry, temperature, mixing energy, test protocol, can also influence the determination of the rheological properties of these composites. In this sense, the aim of this study is to evaluate the influence of mixing energy and pre-shear on the rheological properties of cement pastes. For this purpose, samples with water/cement ratios equal to 0.40, 0.45, 0.50, 0.55, 0.60 and 0.65 by weight were studied. Two levels of mixing energy were used: low intensity mixing (maximum rotation equal to, approximately, 270 rpm), with a planetary mixer; and high intensity mixing (maximum rotation equal to, approximately, 12,000 rpm) with a high shear mixer. Two test protocols were established, one with zero pre-shear (resting for 90 s of the sample in the rheometer) and the other with application of a constant shear rate equal to 100 s–1, for 60 s, followed by rest of the material for 30 s. The results indicated that the mixing energy and pre-shear significantly influence the rheological behavior of cement pastes with higher solids volume (w/c ratio ≤ 0.45).
  • ItemArtigo
    Membrane aerated biofilm reactor in recirculating aquaculture system for effluent treatment
    (2022-01-01) Almeida, Juliana Cristina Ribeiro ; Bega, João Miguel Merces ; Leite, Luan de Souza ; de Oliveira, Jefferson Nascimento ; Albertin, Liliane Lazzari ; Matsumoto, Tsunao ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP)
    The implementation of fish farming has been increasing worldwide over the last decades, as well the search for alternative production systems and the treatment of their generated effluent. Recirculating Aquaculture System (RAS) is a compact solution for future intensive fish farming. However, few configurations of treatment technologies were tested in RAS, such as systems with a Membrane Aerated Biofilm Reactor (MABR). In this scene, this study aimed to evaluate the RAS effluent treatment efficiency device for intensive Nile tilapia (Oreochromis niloticus) production, the fish species most cultivated worldwide. The novel RAS configuration was composed of a cultivation tank (CT), a Column Settler, and a MABR. The RAS performance was evaluated by pH, temperature, turbidity, dissolved oxygen (DO), total nitrogen (TN), ammonia, nitrite, nitrate, total solids (TS), and chemical oxygen demand (COD). The obtained results in average values for temperature, pH, and DO inside the CT were 25.22 ± 1.88°C, 7.61 ± 0.33, and 3.80 ± 1.30 mg L−1, respectively, as ideal for tilapias survival. Average removal efficiencies found in the RAS for turbidity, COD, TN, nitrite, nitrate, ammonia, and TS were 50.0, 40.5, 11.7, 40.2, 13.1, 35.0, and 11.4%, respectively. Overall, we observed removals for all parameters studied, with good results, particularly, for COD, turbidity, nitrite, and ammonia. The evaluated system proved an effective alternative for water reuse in RAS capable of maintaining water quality characteristics within the recommended values for fish farming.
  • ItemResenha
    Particleboards Manufactured from Tectona grandis Wood Waste with Homogeneous and Three-layer Heterogeneous Compositions for Commercial Purposes
    (2022-01-01) de Souza, Matheus V. ; da Silva, Sérgio A. M. ; Cazella, Pedro H. S. ; Rodrigues, Felipe R. ; Bonfim, Kely S. ; Sanches, Alex O. ; De Araujo, Victor A. ; Dos Santos, Herisson F. ; Pinto, Edna M. ; Christoforo, André L. ; Aouada, Márcia R. M. ; Aouada, Fauze A. ; Lahr, Francisco A. R. ; Universidade Estadual Paulista (UNESP) ; Universidade Federal de São Carlos (UFSCar) ; Universidade Estadual de Maringá (UEM) ; Federal University of Rio Grande do Norte (UFRN) ; Universidade de São Paulo (USP)
    Tectona grandis wood presents decent dimensional stability as well as highly suitable physical and mechanical properties. These characteristics have encouraged the intense usage of this species, which also includes the reuse of wood processing waste for panel production. Using teak wood waste, this study aims to manufacture and evaluate heat-pressed particleboards at 5 MPa and 100 °C, by being glued with castor oil-based polyurethane resin at proportions of 10% for the homogeneous boards and 12% for the heterogeneous solutions. Single-layer (homogeneous) boards were compared with three-layer particleboard specimens (heterogeneous) having the finer particles in the outer layers. The basic density, moisture content, modulus of rupture and modulus of elasticity in the static bending and perpendicular tensile, water absorption, and thickness swelling after 24 h were evaluated to support this comparative study. All the manufactured particleboards met the standardized requirements of performance, thus being very feasible for usage as non-structural boards. When the two different compositions were analyzed, a considerably better performance of the three-layered particleboards was identified when compared to the homogeneous panels.
  • ItemResenha
    Production and Evaluation of Particleboards Made of Coconut Fibers, Pine, and Eucalyptus using Bicomponent Polyurethane-Castor Oil Resin
    (2022-01-01) Bispo, Rodrigo Andraus ; Trevisan, Mariana Ferreira ; da Silva, Sérgio Augusto Mello ; Aquino, Vinícius Borges de Moura ; Saraiva, Raísse Layane de Paula ; Arroyo, Felipe Nascimento ; Molina, Julio Cesar ; Chahud, Eduardo ; Branco, Luiz Antonio Melgaço Nunes ; Panzera, Túlio Hallak ; Lahr, Francisco Antonio Rocco ; Christoforo, André Luis ; Universidade Estadual Paulista (UNESP) ; Federal University of Southern and Southeastern Pará ; Universidade Federal de São Carlos (UFSCar) ; Universidade Federal de Minas Gerais (UFMG) ; Federal University of São João del-Rei ; Universidade de São Paulo (USP)
    This research examined the influence of the compositions between coconut fiber (Cocos nucifera) and wood particles (Pinus taeda L. and Eucalyptus saligna) on physico-mechanical properties of homogeneous particleboards. The exploratory study was carried out under Tukey's contrast test of means, at 5% significance level, with the following compositions: 100% coconut fiber (F100 P0 E0); 50% coconut fiber, 25% pine particles, and 25% eucalyptus particles (F50 P25 E25); and 50% of pine particles and 50% of eucalyptus particles (F0 P50 E50), with particle moisture content between 0% to 2% and 10%, in mass, of polyurethane-castor oil (PU-Castor) resin. Three panels were produced for each composition. The physico-mechanical properties such as density, moisture content, swelling in thickness after 24 h of immersion in water, perpendicular tensile strength, static bending strength, and modulus of elasticity were evaluated using standard methods. The results obtained indicated the potential for using coconut fiber for the production of homogeneous particleboards in view of the minimum criteria required by the normative documents, with emphasis on the physical property of swelling after 24 hours, which obtained a statistically equivalent average relative to the treatment that contained only wood particles.
  • ItemArtigo
    PDI techniques applied to the automatic identification and extraction of anthropogenic activities
    (2022-01-01) Dos Santos, Arthur Pereira ; Simionatto, Henzo Henrique ; Xisto, Luana Aparecida Duarte ; Universidade Estadual Paulista (UNESP)
    The use of Digital Image Processing (PDI) consists in adjusting the visual characteristics of the image in order to provide contributions to its interpretation and generate products that can later be subjected to further processing. Among the DIP techniques, the segmentation of objects in the image is highlighted by the possibility of distinguishing the region of interest from the background of the image. Therefore, this work aimed to perform the segmentation of anthropic activities in an image of the city of Paracatu-MG that included both the urban network of the city and the area of open-pit mineral extraction. To this end, we used a satellite image that contemplated the reality of the municipality. Initially, the Otsu method was used to perform the segmentation of the tree and underbrush vegetation and the image histogram was calculated in gray levels for each input (red channel (R); green channel (G) and; blue channel (B)). From this, weights and averages for the front and background classes of the image were calculated until an optimal threshold was found. In order to verify the possibility of segmenting the open-pit mineral extraction area and the urban mesh of the Paracatu municipality, the Region Growth (RC) method was chosen. Finally, the morphological operation of closure was performed in the segmented regions, so that the gaps were added to the original regions of the image and compared the results of the segmentation of the Otsu method with the segmentation by threshold. It was verified that it was possible to achieve the proposed objective through the PDI techniques and that the segmentation of the images can be used as a previous form of processing that can assist in computational techniques.
  • ItemArtigo
    Water quality of the Paraná river in a bathing resort region: a discussion on the potential impacts of secondary treated wastewater discharge
    (2022-01-01) Ribeiro, Natasha Ulhiana Ferreira ; Bega, João Miguel Merces ; Zambrano, Karen Tavares ; Américo-Pinheiro, Juliana Heloisa Pinê ; de Carvalho, Sergio Luis ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP) ; Universidade Brasil
    The headwater of the Paraná River became the recipient water body for the Aparecida do Taboado’s Wastewater Treatment Plant effluents — Mato Grosso do Sul — in a project started in 2013 and completed in 2020. The emissary is located upstream of a bathing resort. This study aimed to monitor the river water quality before discharge starts, from August 2019 to February 2020. The CETESB Water Quality Index and its calculation parameters were used. The Paraná River presented good water quality (Water Quality IndexCETESB ≥72) and the absence of Escherichia coli. Nevertheless, 57 and 61% of the samples did not meet CONAMA Resolution No. 357/05 for biochemical oxygen demand and total phosphorus, respectively. Potential negative impacts on the water quality are related to the parameters of biochemical oxygen demand, total phosphorus and Escherichia coli and the secondary treated wastewater discharge into Paraná River may result in the water quality deterioration, compromising its multiple uses.
  • ItemArtigo
    Impedance Spectroscopy as a Methodology to Evaluate the Reactivity of Metakaolin Based Geopolymers
    (MPDI, 2022-11-25) Sanches, Alex Otávio ; Istuque, Danilo Bordan ; Bortoletto, Marcelo ; Malmonge, José Antônio ; Soriano, Lourdes ; Borrachero, María Victoria ; Payá, Jordi ; Tashima, Mauro M. ; Akasaki, Jorge Luis ; Universidade Estadual Paulista (Unesp)
    The aim of this study was to use the electrical impedance spectroscopy technique (IS) to carry out a systematic study on the mechanism of metakaolin geopolymerization for up to 7 curing days. The study was developed on two batches of metakaolin (MK), and their reaction processes were compared. Interpretative fundamental elements were developed based on the effective electrical conductivity curves regarding the metakaolin geopolymerization. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were previously carried out and used to interpret and validate the electrical behavior of the fresh and hardened MKbased geopolymer pastes. The results highlighted the sensibility of the impedance technique to the identification and description of the MK geopolymerization process, as well as the changes resulting from even slight variations in the metakaolin composition. Furthermore, this indicated that the geopolymerization process in highly alkaline solutions could be divided into seven stages, including the processes of dissolution, nucleation, precipitation and formation of the gel and, eventually, the retraction/microcracks constitution. Late dissolution processes could be observed during the more advanced stages and were attributed to particles not being fully hydrated.
  • ItemArtigo
    Analysis of water performance of coating mortars incorporated with tire rubber
    (Pontificia Univ Catolica Chile, Dept Ingenieria & Gestion Construccion, 2022-04-01) Pagoto, Leticia Martelo ; Akasaki, Jorge Luis ; Melges, Jose Luiz Pinheiro ; Fioriti, Cesar Fabiano ; Universidade Estadual Paulista (UNESP)
    This paper analyzed the behavior of mixed mortars incorporated with rubber from the tire retreading process, based on partial sand substitution. The content of rubber incorporation in the mortars was 5%, 10%, 15%, and 20% by volume. The different granulometries of rubber were denominated as thick (passed through a sieve # 1.19 mm) and fine (passed through a sieve # 0.60 mm). Tests were performed to evaluate water retention, capillary absorption, drying, immersion absorption, water vapor permeability, and permeability to water under pressure. The results showed that the fine rubber was distinguished by its higher retention of water at the contents of 15% and 20%, lower absorption via both capillary and immersion, higher drying capacity, higher permeability to water vapor, and lower permeability to water under pressure.