Gold and platinum bimetallic nanoparticles, Au@PtNPs, have gained attention due to their plasmonic properties. The controlled synthesis of Au@PtNPs involves complex parameters, and the resulting synergy between Au and Pt introduces possibilities for tailoring their properties. This study explores the effects of key-parameters of synthesis (gold core diameters, reaction time, and Pt concentration) on the final properties of Au@PtNPs. Gold nanoparticles of varying diameters were synthesized and used as cores for the reduction of hexachloroplatinic acid, forming a surrounding shell of Pt nanoparticles. The parameters were systematically tuned to understand their impact on morphology, dimension, stability, and plasmonic properties of Au@PtNPs. Increasing Pt precursor concentration resulted in thicker and denser Pt shells, broadening the localized surface plasmon resonance (LSPR) band and improving Au@PtNPs stability. These properties are essential for applications such as photothermal treatment. The synthesis achieved satisfactory products within just 1 h of Pt4+ reduction at mild temperature without using surfactants. Only limited changes in plasmonic properties were observed after 4 h of synthesis, suggesting an optimal reaction period. Manipulating Au core diameter provided LSPR band control, with smaller cores exhibiting greater broadening towards the infrared region. This systematic exploration provided valuable insights for understanding key-parameters governing the synthesis and properties of Au@PtNPs. AuPtNPs PtNPs keyparameters key gold time acid morphology dimension stability shells (LSPR treatment Pt4 surfactants period control region

EFFECT OF LIQUID SWINE WASTEWATER DOSES ON PHYSICAL, CHEMICAL AND ELECTROCHEMICAL ATTRIBUTES IN A CERRADO OXISOL. The addition of organic residues enhances soil and plant organic matter and nutrient content. To gauge the impact of varying liquid swine waste (LSW) levels on soil, we studied changes in a clayey Oxisol’s physical, chemical, and electrochemical traits from the Cerrado. LSW doses (0, 50, 150, 450, 600 m3 ha−1) were applied to the 0-0.20 m layer in a randomized design with three replicates. Post a 30-day incubation at 60% field capacity, the soil underwent mineralogical, physical (clay dispersed in water - CDW), chemical (sodium adsorption ratio - SAR, cation exchange capacity - CEC, base saturation - V%), and electrochemical (pH in H2O and KCl, ApH, point of zero charge - PZC, point of zero salt effect - PZSE, surface electric potential - iµo, and electrical conductivity - EC) analyses. The levels of exchangeable Ca, K, Mg, Na, and available P increased with increasing LSW doses. Increasing LSW doses in the soil led to an increase in EC, but soil salinization was not observed at the highest dose. With the application of LSW doses, there was a decrease in pH, ApH, PZSE, and an increase in CEC, PZC and ψo. Despite the increase in ψo, low clay dispersibility was observed. PHYSICAL OXISOL content (LSW Oxisols Oxisol s Cerrado 0, 0 (0 50 150 450 60 ha−1 ha1 ha 1 00.20 0020 0.20 20 0-0.2 replicates 30day day 30 mineralogical CDW, CDW , CDW) sodium SAR CEC V%, V V% V%) pH HO H O KCl ApH PZSE iµo EC analyses Ca K Mg Na dose ψo ( 5 15 45 6 ha− 00 00.2 002 020 0.2 2 0-0. 3 4 00. 02 0. 0-0 0-

In this work, using the PM3 semi-empirical method, the oxidation of the single-walled carbon nanotube (SWCNT) was studied by sulfuric and nitric acid for the incorporation of carbonyl (C=O), phenol (OH) and carboxylic (COOH) groups in the C=C bonds present on the surface of the nanotube. Subsequently, the crosslinking of the oxidized SWCNT (SWCNTox) and chitosan (Q) was observed through hydrogen bonds of the C=O and OH bonds with 2.34 Å, the process was endothermic and soluble in polar solvents due to the presence of OH and NH groups in the structure of SWCNTox/Q. The Monte Carlo modeling allowed to study the adsorption of pesticides in the SWCNTox/Q at different temperatures, where the QSAR (quantitative structure activity relationship) properties allowed predicting the behavior of the pesticides, that is, the degree of hydrophobicity (log P) and accessible surface area (ASA) were important parameters in the evaluation of SWCNTox/Q as an adsorbent and surface interacting with pesticides respectively. Finally, the adsorption was a physisorption process due to the electronegativity of the CO, OH, NH2, NH and C=O bonds. work PM semiempirical semi empirical method singlewalled single walled (SWCNT C=O, CO , C O (C=O) (OH COOH (COOH CC Subsequently SWCNTox (SWCNTox Q (Q 234 2 34 2.3 Å SWCNToxQ temperatures quantitative relationship is log P ASA (ASA respectively Finally NH2 (C=O 23 3 2.

The recycle and utilization of expired drugs is a challenge for many countries at present. The employment of expired drugs as green corrosion inhibitors is expected to address both drug recycling and corrosion prevention issues, with significant economic and environmental value. Herein, the individually and combination corrosion inhibition performance of expired amoxicillin (AMC) and penicillin V potassium tablets (PVP) for lowcarbon steel in 20% acetic acid solution containing 600 mg L-1 chloride ion are evaluated by electrochemistry and weight loss method. Both the AMC and PVP present the mixed-type corrosion inhibitors mainly affect the cathode process when used individually. The optimum inhibition efficiency is 61.22% (AMC) and 79.21% (PVP), which all appear in 5.0 × 10-3 mol L-1. The AMC and PVP are adsorbed on the steel surface by mixed physisorption and chemisorption, which are consistent with the Langmuir adsorption isotherm. The corrosion inhibition rate drops sharply when AMC and PVP are combined use with a close mole ratio. But a small amount of PVP significantly enhance the corrosion inhibition effect of AMC, the corrosion inhibition rate from 61.22 to 79.72%. The corrosion inhibition rate of AMC and PVP combination inhibitor decreased with the increase of temperature. issues value Herein (AMC (PVP 20 60 L1 L 1 L- method mixedtype type 6122 61 22 7921 79 21 79.21 PVP, , 50 5 0 5. 103 10 3 10- L1. 1. chemisorption isotherm ratio 61.2 7972 72 79.72% temperature 2 6 612 792 7 79.2 61. 797 79.72 79. 79.7

The present work reports the in situ fabrication of Ag nanoparticles (AgNPs) in polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) over pre-patterned hydrophobic stripes on a hydrophilic glass surface. Microcontact printing (μCP) using octadecyltrichlorosilane (OTS) as “ink” was used to obtain these chemically modified substrates. A comparison of the results of the PS-b-P2VP self-assembly over a bare glass substrate and a pre-patterned glass substrate demonstrated the influence of the pattern on the film morphology. Polymeric films of Ag+ and PS-b-P2VP were prepared on a pre-patterned substrate and heated at 150 °C to enable the self-reconstruction of the polymeric matrix and the in situ formation of AgNPs (average particle size of approximately 100 nm). The AgNP/PS-b-P2VP thin films were characterized using UV-Vis spectroscopy and atomic force microscopy. The results demonstrate that the concentration of the solutions of Ag+/PS-b-P2VP used to prepare the films strongly influences the morphologies and dispersion of AgNPs. Moreover, the surface-enhanced Raman spectroscopy (SERS) activity of the fabricated polymer nanocomposites using Nile Blue as a molecular probe shows the importance of the chemical modification of the substrate in the enhancement of the SERS signal. (AgNPs polystyrenebpoly2vinylpyridine polystyrenebpolyvinylpyridine polystyrene b poly 2 vinylpyridine polystyrene-b-poly(2-vinylpyridine PSbP2VP PSbPVP PS P2VP P VP (PS-b-P2VP prepatterned pre patterned surface μCP (μCP OTS (OTS ink “ink substrates selfassembly self assembly morphology 15 C selfreconstruction reconstruction average 10 nm. nm . nm) AgNP/PSbP2VP AgNPPSbP2VP AgNPPSbPVP AgNP/PS AgNP UVVis UV Vis microscopy Ag+/PSbP2VP AgPSbP2VP AgPSbPVP Ag+/PS Moreover surfaceenhanced enhanced (SERS signal polystyrenebpoly PSbP PVP 1 AgNPPSbP AgNPPS AgPSbP AgPS

In the Amazon, Euterpe oleracea Mart. (açaí), is part of the identity of traditional communities, and the fruit is integrated into their everyday sociocultural dynamics. Hydrolysis and pyrolysis of residual biomass can be alternatives to yield sugars, ethanol, biochar and bio-oil. The açaí seeds subjected to oxidative pretreatment followed by acid hydrolysis increased cellulose to fermentable sugars (reaching 23.5%) and second-generation ethanol production (17.441 L t−1). Açaí oil (ca. 30%) was extracted using a Soxhlet apparatus (using hexane as solvent) and detected through gas chromatography coupled to mass spectrometry (GC-MS), where acids accounted for 82.43% of the total composition, while alcohols comprised only 13.15%. For pyrolysis, temperatures (500 and 550 °C), time (20 and 30 min), and activation temperature (750 and 800 °C) were evaluated, resulting in yields of ca. 22% for biochar and 30% for bio-oil. For the bio-oil, the main compounds detected by GC-MS were acids (16.3%), aldehydes (13.08%), amides (12.19%), alcohols (6.72%), and phenols (4.64%). The obtained biochar displayed surface area values of 553.7 m2 g−1 and 10% crystallinity, indicating its more amorphous nature. Amazon Mart açaí, , (açaí) communities dynamics biooil. biooil bio oil. bio-oil reaching 23.5% 235 23 5 secondgeneration second generation 17.441 17441 17 441 (17.44 t−1. t1 t t−1 . 1 t−1) ca (ca solvent GCMS, GCMS GC MS (GC-MS) 8243 82 43 82.43 composition 1315 13 15 13.15% 500 (50 55 °C, C °C 20 (2 3 min, min min) 750 (75 80 evaluated 22 biooil, oil, 16.3%, 163 16.3% 16 (16.3%) 13.08%, 1308 13.08% 08 (13.08%) 12.19%, 1219 12.19% 12 19 (12.19%) 6.72%, 672 6.72% 6 72 (6.72%) 4.64%. 464 4.64% 4 64 (4.64%) 5537 553 7 553. m g1 g g− 10 crystallinity nature (açaí 23.5 2 17.44 1744 44 (17.4 t− (GC-MS 824 8 82.4 131 13.15 50 (5 ( 75 (7 16.3 (16.3% 130 13.08 0 (13.08% 121 12.19 (12.19% 67 6.72 (6.72% 46 4.64 (4.64% 23. 17.4 174 (17. 82. 13.1 16. (16.3 13.0 (13.08 12.1 (12.19 6.7 (6.72 4.6 (4.64 17. (17 13. (16. (13.0 12. (12.1 6. (6.7 4. (4.6 (1 (16 (13. (12. (6. (4. (13 (12 (6 (4

ABSTRACT A patient presented with corneoscleral thinning five months after the treatment of suspected ocular squamous surface neoplasia with mitomycin-C and interferon. For tectonic and aesthetic purposes, we decided to perform lamellar corneoscleral transplantation. The approach used established new tectonic support and corneal homeostasis. This technique might be an option in similar cases. mitomycinC mitomycin C interferon purposes transplantation homeostasis cases

We report a facile hydrothermal method for the synthesis of niobium pentoxide (Nb2O5) under two different temperatures, 120 °C (Nb2O5-120) and 150 °C (Nb2O5-150). The obtained materials were characterized by structural, optical and morphological techniques. Also, the photocatalytic properties of the Nb2O5 samples were evaluated in two reactions under ultraviolet (UVC) irradiation: degradation of methylene blue (MB) and indigo carmine (IC) dyes; and esterification of free fatty acids (FFA) present in waste cooking oil (WCO). The Nb2O5 was formed at different temperatures of synthesis, and the increase in temperature did not cause significant changes in the structural and optical characteristics, but resulted in an increased surface area of the synthesized materials. Both synthesized materials showed excellent efficiency for dye photodegradation. The sample Nb2O5-150 presented the best performance for the MB photodegradation, with almost 85% of the removal efficiency. In this case, the adsorption of MB molecules on the surface of the material was high due to the favorable electrostatic interaction and also because of its high surface area. For the IC photodegradation, the adsorption was insignificant, and both samples presented approximately 100% of the removal efficiency. These materials were also promising for the reduction of free fat acids in waste oil by photoesterification. NbO Nb O (Nb2O5 12 C Nb2O5120 (Nb2O5-120 15 Nb2O5150. Nb2O5150 . (Nb2O5-150) techniques Also Nb2O UVC (UVC irradiation (MB (IC dyes FFA (FFA WCO. WCO (WCO) characteristics photodegradation Nb2O5-15 85 case insignificant 100 photoesterification (Nb2O 1 Nb2O512 (Nb2O5-12 Nb2O515 (Nb2O5-150 (WCO Nb2O5-1 8 10 Nb2O51 (Nb2O5-1 (Nb2O5-15 Nb2O5- (Nb2O5-

The acetalization or transacetalization reactions produce acetals or ketals used in cosmetics, food, pharmaceuticals, and fuel additives. Besides synthesizing several products, the acetalization or transacetalization reactions can protect carbonyl groups, 1,2 and 1,3-diols in multi-step synthesis. This work studies the transacetalization of glycerol with 2,2-dimethoxypropane (2,2-DMP) to yield 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane (solketal) by catalyzing with USY, HBeta, and HZSM-5 zeolites under cleaner and mild reaction conditions (reaction temperature: 25 °C; 2,2-DMP/glycerol molar ratio: 1; reaction time: 1 h; and catalyst concentration: 0.05-5 wt.%). For catalyst concentration equal to or greater than 2,5 wt.%, glycerol conversion stabilized near 96-97% for the three zeolites tested. The product selectivities also assume a constant value, close to 97% for solketal. For the lowest concentration of catalyst, the influence of the zeolite properties on the glycerol conversion, such as acidity and the strong/weak acid site ratio, was observed. Concerning the selectivity of the products, the results suggested that it can be based on zeolite topology, active sites at the particle surface, and the relative amount of micro and mesoporous HBeta, the most selective catalyst for acetals production, was reused at least once without loss of activity and selectivity. cosmetics food pharmaceuticals additives products groups 12 2 1, 1,3diols 13diols diols 1,3 3 multistep multi step synthesis 2,2dimethoxypropane 22dimethoxypropane dimethoxypropane 2,2 2,2DMP 22DMP DMP (2,2-DMP 2,2dimethyl4hydroxymethyl1,3dioxolane 22dimethyl4hydroxymethyl13dioxolane dimethylhydroxymethyldioxolane dimethyl 4 hydroxymethyl dioxolane solketal (solketal USY HBeta HZSM5 HZSM 5 HZSM- temperature °C C 2,2DMP/glycerol 22DMPglycerol DMPglycerol DMP/glycerol ratio time h 0.055 0055 0.05 0 05 0.05- wt.%. wt wt.% . wt.%) 2, 9697% 9697 96 97 96-97 tested value strongweak strong weak observed topology surface production 3diols 13 2dimethoxypropane 22 2DMP 2dimethyl4hydroxymethyl1 3dioxolane 055 005 0.0 wt. 969 9 96-9 dimethylhydroxymethyl 2dimethyl4hydroxymethyl 00 0. 96-

Silver film is commonly used to examine the structure and composition of molecules due to its surface-enhanced Raman scattering (SERS) effect. A simple method for preparing SERS silver films is proposed in this paper by electrodeposition in an amide-based liquid mixture (urea-acetamide-LiBr). The electrochemical behavior of silver in urea-acetamide-LiBr mixture was studied by cyclic voltammetry (CV) and chronoamperometry. It was found that the nucleation mechanism of silver shifts to instantaneous nucleation under diffusion control with increasing overpotential and temperature. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) investigations confirmed that the obtained deposits are pure silver. Scanning electron microscopy (SEM) analysis showed that the morphology of the silver deposits depends on the deposition potential and temperature. Rhodamine 6G was used as probe molecules for SERS experiments, showing that these new active substrates have high sensitivity to SERS response with high enhancement factors, of approximately 107, and enable Raman scattering even for diluted solutions. surfaceenhanced surface enhanced (SERS effect amidebased amide based ureaacetamideLiBr. ureaacetamideLiBr urea acetamide LiBr . (urea-acetamide-LiBr) CV (CV chronoamperometry temperature EDS (EDS Xray X ray XRD (XRD SEM (SEM G experiments factors 107 solutions (urea-acetamide-LiBr 10 1

RESUMO A aplicação de esgoto sanitário utilizando o gotejamento subsuperficial contribui para mitigar os problemas atuais de disponibilidade de água e produção de alimento. Objetivou-se avaliar o feijão-caupi recebendo esgoto sanitário por gotejadores operando com diferentes vazões e profundidades. Os gotejadores operaram com as vazões de 1,6 e 3,8 L h-1 e foram instalados nas profundidades de 0, 5, 10, 15, 20, 25 e 30 cm. O feijão-caupi foi cultivado em vasos de 65 L preenchidos com solo argiloso em casa de vegetação. Utilizou-se esgoto sanitário sintético e a quantidade aplicada nos vasos foi baseada no elemento limitante, que no caso foi o nitrogênio, para o cultivo do feijão-caupi. O manejo da irrigação foi realizado com sondas de TDR. Avaliou-se a germinação e as respostas fisiológicas e morfologia das raízes do feijão-caupi. A ascensão capilar, quando a água foi aplicada em profundidade, não foi suficiente para umedecer de maneira uniforme a superfície do solo. As variáveis de germinação apresentaram um decréscimo em função do aumento das profundidades de instalação dos gotejadores. A distribuição da água com o aumento da profundidade dos emissores foi responsável pelos prejuízos nas respostas fisiológicas e morfológicas das raízes feijão-caupi. As vazões dos gotejadores não afetaram a germinação do feijão-caupi. Utilizar o sistema de irrigação por gotejamento subsuperficial não foi apropriado para o feijão-caupi nas condições deste estudo. alimento Objetivouse Objetivou se feijãocaupi feijão caupi 16 1 6 1, 38 3 8 3, h1 h h- 0 5 10 15 20 2 cm vegetação Utilizouse Utilizou limitante nitrogênio feijãocaupi. caupi. TDR Avaliouse Avaliou capilar estudo

ABSTRACT The application of sanitary sewage using subsurface drip irrigation contributes to mitigating the current problems of water availability and food production. The aim in this study was to evaluate cowpea receiving sanitary sewage through drippers operating at different flow rates and depths. The drippers operated at flow rates of 1.6 and 3.8 L h-1 and were installed at depths of 0, 5, 10, 15, 20, 25, and 30 cm. Cowpea was grown in 65 L pots filled with sandy clay soil in a greenhouse. Synthetic sanitary sewage was used and the amount applied to the pots was based on the limiting element, which in this case was nitrogen, for growing cowpea. Irrigation was managed using TDR probes. Germination and the physiological responses and morphology of cowpea roots were assessed. Capillary rise, when water was applied in subsurface, was not sufficient to evenly moisten the soil surface. The germination variables decreased as a result of the increase in drip installation depths. The distribution of water as the depth of the emitters increased was responsible for the damage to the physiological and morphological responses of cowpea roots. The flow rates of the drippers did not affect the germination of cowpea. Using the subsurface drip irrigation system was not appropriate for growing cowpea under the conditions of this study. production 16 1 6 1. 38 3 8 3. h1 h h- 0 5 10 15 20 25 cm greenhouse element nitrogen probes assessed rise surface 2

ABSTRACT Langerhans cell histiocytosis comprises a heterogeneous range of clinical manifestations secondary to clonal proliferation of histiocytes, characterized by the accumulation of these cells in various organs and tissues. The ophthalmological component commonly involved is the orbit. Herein, we report a rare case of Langerhans cell histiocytosis with eyelid involvement, which resulted in severe ocular surface complications, which subsequently significantly impacted the patient’s quality of life. This case report highlights the fact that despite being rare, Langerhans cell histiocytosis should be included in the differential diagnosis of eyelid lesions. Furthermore, a multidisciplinary approach with a systemic overview is crucial for managing the ocular complications. histiocytes tissues orbit Herein involvement complications patients patient s life lesions Furthermore

ABSTRACT Purpose: To evaluate the effect of upper eyelid ptosis repairwith Muller muscle-conjunctival resection on meibomian gland function and ocular surface parameters. Methods: Thirty-eight patients who underwent ptosis repair with Muller muscle-conjunctival resection were retrospectively reviewed. Meibomian gland loss, Ocular Surface Disease Index OXFORD score, meiboscore, and noninvasive keratograph break-up time were measured preoperatively and at 1st, 3rd, and 6th months postoperatively. Results: Noninvasive keratograph break-up time values decreased significantly at 1st and 3rd months postoperatively compared to the preoperative level, but were similar to the preoperative level at 6th months postoperatively (p<0.001 and p=0.628, respectively). Ocular surface disease index, OXFORD score, meibomian gland loss, and meiboscore values increased significantly in the 1st and 3rd postoperative months compared to the preoperative period, but these values decreased to preoperative levels in the 6th postoperative month (p<0.001 and p>0.05, respectively). Conclusion: There is a transient deterioration in meibography findings and OSDI score in the early postoperative period afterMuller muscle-conjunctival resection. Patients undergoing Muller muscle-conjunctival resection may require topical lubricants, especially in the first 3 postoperative months. Purpose muscleconjunctival muscle conjunctival parameters Methods Thirtyeight Thirty eight reviewed loss breakup break up st rd th Results p<0.001 p0001 p 0 001 (p<0.00 p0628 628 p=0.628 respectively. respectively . respectively) index p005 05 p>0.05 Conclusion lubricants p<0.00 p000 00 (p<0.0 p062 62 p=0.62 p00 p>0.0 p<0.0 (p<0. p06 6 p=0.6 p0 p>0. p<0. (p<0 p=0. p>0 p<0 (p< p=0 p> p< (p p=

Abstract This study investigated the effects caused by the thermal shock phenomenon on the temperature distribution in Adhered Ceramic Tiling Systems (ACTS). Cyclic thermal and hygroscopic loads are periodic events resulting from successive and sequential processes of heating by solar irradiation and sudden cooling by heavy rains. Through an experimental program carried out in a ceramic tile prototype composed of porcelain tiles settle with adhesive mortar directly on a concrete wall, monitored the surface temperatures and temperatures at the adhesive mortar-concrete interface were measured during its exposure to heating and cooling cycles according to NBR 15575-4 (ABNT, 2021) procedures. The confinement of thermal energy (heat) inside the structure, after the beginning of cooling, demonstrates that part of the thermal stresses is maintained internally to the structure even after the drop-in surface temperature of the ceramic tile (non-homogeneous distribution), indicating that the movements structural elements of thermal origin will tend to different directions (non-uniform) and, consequently, will cause opposite stresses between layers. This results in a possible increase and concentration of stresses in certain regions that, if critical, will lead to the appearance of damage in the ceramic coating. ACTS. ACTS . (ACTS) rains wall mortarconcrete 155754 15575 4 15575- ABNT, ABNT (ABNT 2021 procedures heat (heat dropin drop nonhomogeneous non homogeneous distribution, , distribution) nonuniform uniform (non-uniform consequently layers critical coating (ACTS 1557 202 155 20 15 2 1

Resumo O estudo investigou os efeitos causados pelo fenômeno do choque térmico sobre a distribuição de temperatura em sistemas de revestimento cerâmico aderido (SRCA). Carregamentos cíclicos térmicos e higroscópicos são eventos periódicos resultado de processos sucessivos e sequenciais de aquecimento por irradiação solar e resfriamentos bruscos por chuvas. Por meio de um programa experimental realizado em um protótipo de revestimento cerâmico composto de placas de porcelanato assentadas com argamassa colante diretamente sobre uma parede de concreto, monitoraram-se as temperaturas superficiais e na interface argamassa colante-concreto durante sua exposição a ciclos de aquecimento e resfriamento, conforme procedimentos da NBR 15575-4 (ABNT, 2021). O confinamento de energia térmica (calor) no interior da estrutura, após o início do resfriamento, demonstra que parte dos esforços térmicos é mantida internamente à estrutura mesmo após a queda de temperatura superficial da placa cerâmica (distribuição não homogênea), indicando que as movimentações estruturais de origem térmica tenderão a ir em direções diferentes (não uniformes) e, consequentemente, ocasionarão solicitações opostas entre camadas. Isso resulta em possível acréscimo e concentração de tensões em determinadas regiões, que, se críticas, levarão ao surgimento do dano no revestimento cerâmico. SRCA. SRCA . (SRCA) chuvas concreto monitoraramse monitoraram colanteconcreto resfriamento 155754 15575 4 15575- ABNT, ABNT (ABNT 2021. 2021 2021) calor (calor homogênea, homogênea , homogênea) uniformes consequentemente camadas regiões críticas (SRCA 1557 202 155 20 15 2 1

Abstract The present paper evaluated the potential application of the functionally graded material (FGM) concept to develop more durable concrete to carbonation, one of the main degradation mechanisms of reinforced concrete structures. Accelerated carbonation tests with controlled temperature (27 ( 2°C), CO2 concentration (3 ( 0.5%) and humidity (65 ( 5%) were carried out in homogeneous concretes and with functional gradation in which the porosity of the material was varied across the slices. For the manufacture of graded concrete specimens, concretes with water/cement ratios equal to 0.35, 0.45, and 0.55 were produced, with lower porosity (w/c = 0.35) close to the surface of the specimen. The advance of the carbonation front was evaluated after 8, 9, 10, 14, and 24 weeks of accelerated exposure, using the chemical indicator phenolphthalein. The results show that the functionally graded concrete had a carbonation coefficient (K) slightly higher than that of the concrete with a w/c ratio equal to 0.35 (1.71 and 1.54 mm.week-0.5, respectively) and much lower than concrete with water-cement ratio equal to 0.45 (2.31 mm.week-0.5) and 0.55 (3.78 mm.week-0.5). This demonstrates that functional grading can be an efficient method to increase the durability of concrete elements subject to carbonation. FGM (FGM structures 27 (2 2°C, 2C C 2°C , 2 2°C) CO 3 0.5% 05 0 5 65 (6 5% slices specimens watercement water cement 035 35 045 45 055 55 0.5 produced wc w c specimen 8 9 10 14 exposure phenolphthalein K (K 0.3 1.71 171 1 71 (1.7 154 54 1.5 mm.week0.5, mmweek05 mmweek mm.week 0.5, mm week mm.week-0.5 respectively 0.4 2.31 231 31 (2.3 mm.week0.5 3.78 378 78 (3.7 mm.week0.5. . 6 03 04 4 0. 1.7 17 7 (1. 15 1. week0 mmweek0 mm.week-0. 2.3 23 (2. mm.week0. 3.7 37 (3. (1 mm.week-0 2. mm.week0 3. mm.week-

Resumo O presente artigo avalia o potencial de aplicação do conceito de material com gradação funcional (MGF) ao desenvolvimento de concretos mais duráveis frente à carbonatação, um dos principais mecanismos de degradação das estruturas de concreto armado. Ensaios acelerados de carbonatação com temperatura (27 ( 2 °C), concentração de CO 2 (3 ( 0,5%) e umidade (65 ( 5%) controladas foram realizados em concretos homogêneos e com gradação funcional em que a porosidade do material foi variada ao longo dos corpos de prova. Para a confecção dos corpos de prova de concreto com gradação funcional foram utilizados concretos com relações água/cimento iguais a 0,35, 0,45 e 0,55 de forma que tivéssemos uma redução de porosidade à medida que nos aproximássemos da superfície da peça. O avanço da frente de carbonatação foi avaliado após 8, 9, 10, 14 e 24 semanas de exposição acelerada, empregando-se o indicador químico fenolftaleína. A partir dos resultados obtidos observou-se que os concretos com gradação funcional apresentaram coeficiente de carbonatação (K) ligeiramente superior ao do concreto com relação a/c igual a 0,35 (1,71 e 1,54 mm.semana -0,5 , respectivamente) e bastante inferior aos concretos com relação água cimento iguais a 0,45 (2,31 mm.semana -0,5 ) e 0,55 (3,78 mm.semana -0,5 ), evidenciando que a gradação funcional pode ser um método eficiente para proporcionar o aumento da durabilidade de elementos de concreto sujeitos à carbonatação. MGF (MGF armado 27 (2 °C, C °C °C) 3 0,5% 05 0 5 65 (6 5% águacimento 035 35 045 45 0,4 055 55 0,5 peça 8 9 10 1 acelerada empregandose empregando se fenolftaleína observouse observou K (K ac c 0,3 1,71 171 71 (1,7 154 54 1,5 mmsemana mm semana -0, respectivamente 2,31 231 31 (2,3 3,78 378 78 (3,7 6 03 04 4 0, 1,7 17 7 (1, 15 1, -0 2,3 23 (2, 3,7 37 (3, (1 - 2, 3,