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URI Permanente para esta coleçãohttps://repositorio.ipen.br/handle/123456789/8931

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Agora exibindo 1 - 20 de 9744

Chemometric evaluation of ampicillin stability using FTIR spectroscopy and multivariate techniques
2025 - ANJOS, VINICIUS P.; FREIRE, MARIA R.V.B.; STASI, RAFFAELE; SILVA, DANIELA de F.T. da; ZEZELL, DENISE M.
Antibiotic quality has always been a concern in the pharmaceutical industry and the World Health Organization (WHO), especially in the growing and emerging antimicrobial resistance crisis. FTIR spectroscopy can contribute to the monitoring of antimicrobials, especially when coupled with chemometric techniques. The present work aims to investigate spectral differences of Ampicillin samples through FTIR qualitatively and quantitatively, highlighting the spectral differences associated with different degradation conditions (acidic and thermal).
Theoretical investigation of transverse mode instability in Yb-DCFs due to thermally-induced modal coupling
2025 - CARDOSO, ELBIS S.; SAMAD, RICARDO E.; MOTTA, CLAUDIO C.
This paper presents a theoretical investigation of the transverse mode instability (TMI) threshold in Yb-doped doubleclad fibers (Yb-DCFs). The analysis is based on the semi-weak guiding approximation, applied to the LP01 and LP13 modes. The thermally-induced modal coupling is modeled using coupled differential equations, and the TMI threshold is analytically estimated as a function of the fiber core diameter. Results show that, above the critical threshold, power transfer occurs between modes, highlighting the importance of thermal and modal modeling in the design of more stable fibers for high-power applications.
Laser Ablation in Liquids as a Versatile Approach for the Synthesis of Hybrid Nanoparticles with Plasmonic and Magneto-Plasmonic SERS Applications
2025 - LASKOWSKI, DANIELLE; FEILSTRECKER JUNIOR, SIDO; ANJOS, VINICIUS P.; COSTA, KEVIN S.; MACHADO, THIAGO N.; LENZ, JORGE; VIANA, EMILSON R.; GOES, RAFAEL E. de; SCHREINER, WIDO H.; BEZERRA JUNIOR, ARANDI G.
The synthesis of nanomaterials with tunable optical and magnetic properties is essential for applications in nanomedicine, sensing, and bioimaging. This work explores Laser Ablation in Liquid (LASiS) as a clean and efficient method for producing hybrid nanoparticles for use as SERS (Surface-Enhanced Raman Spectroscopy) substrates. We synthesize and characterize two types of hybrid nanoparticles: metallic Au-Ag alloys and core-shell Au-Fe(oxide) structures. The study demonstrates how LASiS enables the engineering of nanomaterials with enhanced properties for electric field amplification in vibrational spectroscopy, highlighting its potential as a versatile tool for nanobiophotonics applications through a unified experimental approach.
Discriminating oral squamous cell carcinoma via µFTIR spectroscopy imaging and tree-based models
2025 - 2025 - PERES, DANIELLA L.; SILVA, DANIELA T. da; FELIPE, JOAQUIM C.; CORREA, LUCIANA; MATOS, LEANDRO L. de; PEREIRA, THIAGO M.; ZEZELL, DENISE M.
This study evaluates the classification of oral squamous cell carcinoma (OSCC) using micro-FTIR hyperspectral imaging and two tree-based models: Random Forest and XGBoost. After preprocessing and PCA, class imbalance was addressed with AllKNN and Tomek Links. Both models achieved high accuracy, and key spectral bands-Amide I, II, and III-were consistently highlighted, supporting their relevance in oral cancer detection.
Impact of sampling strategies on the classification of micro-FTIR hyperspectral data
2025 - PERES, DANIELLA L.; SILVA, DANIELA T.; FELIPE, JOAQUIM C.; CORREA, LUCIANA; MATOS, LEANDRO L. de; MENEZES, MARIO O. de; PEREIRA, THIAGO M.; ZEZELL, DENISE M.
This study evaluated class balancing strategies for classifying oral squamous cell carcinoma (OSCC) in FTIR hyperspectral images using the XGBoost model. Although the dataset was balanced at the image level, spectral quality filtering introduced pixel-level class imbalance. Resampling methods— SMOTE, Tomek Links, and their combination—were tested, as well as AllKNN for redundancy reduction. All approaches outperformed the unbalanced baseline, but the best overall performance metrics were achieved with the combined use of AllKNN and Tomek Links.
AND, OR, and XNOR optical logic gates via pixel-wise modulation with spatial light modulators and 4f system
2025 - PRADO, FELIPE M.; SILVA, SIDNEY L. da; WETTER, NIKLAUS U.
We present a simple optical setup based on two cascaded reflective phase-only spatial light modulators in a 4f configuration to perform basic logic operations in parallel. By adjusting polarization states and encoding binary input patterns as phase masks, we implemented three logic gates (AND, OR, and XNOR) with results consistent with the expected truth tables. The modulation relies on polarizing components to allow pixel-wise control across the entire image. Experimental results show good agreement with the target amplitude distributions and expected results.
ReLU-like nonlinear activation from an Nd:YVO random laser
2025 - PRADO, FELIPE M.; DIPOLD, JESSICA; WETTER, NIKLAUS U.
This work shows a ReLU-like activation function generated by the emission of a Nd:YVO random laser. The emission response was fitted and implemented as a custom activation function in a neural network trained on the MNIST dataset, achieving an accuracy of 96%. This indicates the potential of random lasers as optical activations for future optical neural network architectures.
Optimization of the calcium silicate hydrated compounds synthesis from the recycling of material derived from coal industry waste
2025 - ALCANTARA-DOMINGOS, RAQUEL R.; FUNGARO, DENISE A.
The intensification of society's consumption and population growth are the main aspects that most contribute to negative impacts on living beings and environmental management due to the generation of large quantities of waste generated daily by industrial production processes. As a result, the valorization of these industrial by-products has been highlighted with the aim of obtaining value-added materials. The concepts of reuse and recycling are presented as a new production model aiming at more sustainable processes.: In the present work, the optimization of the synthesis of calcium silicate hydrated compounds was carried out from sulfated coal ash generated in the flue gas desulfurization process in a thermoelectric plant using the two-stage method (alkaline fusion followed by hydrothermal treatment). The studied parameters that influenced the synthesis were fusion time, agitation time, volume of water for the hydrothermal treatment of the samples, and two types of agitators (rod with blade-type propeller and shaking table). XRF and XRD characterized the ash and products. According to the characterization results, the highest crystallinity of calcium silicate hydrated compounds was identified in the product synthesized under the following conditions: fusion time of 3 h; volume of water for hydrothermal treatment of 100 mL; agitation time of 2 h agitator equipped with rod and blade-type propeller.: It can be concluded that sulfated ash is viable as a starting material for the formation of hydrated calcium silicate compounds, following the principles of environmental sustainability and the objectives of the circular economy.
Proposta para investigar o torneamento de Ti6Al4V com ferramentas de metal duro texturizadas a laser
2025 - SOUZA, FELIPE C.R. de; OLIVEIRA, MARIA A. de; ROSSI, WAGNER de; BOING, DENIS; KURODA, MARCELO; MACHADO, ALISSON R.
Este trabalho apresenta a proposta e resultados parciais de uma investigação do efeito de texturas produzidas por laser de femtossegundos na superfície de saída em ferramentas de metal duro no torneamento de Ti6Al4V com fluido aplicado em abundância. As forças de usinagem, rugosidade da peça, vida das ferramentas e morfologia e metalografia dos cavacos foram variáveis de saída consideradas. As variáveis de entrada foram a direção, dimensão e distância da aresta de corte das texturas, velocidade de corte, avanço e presença de lubrificante sólido (MoS2) impregnado nas ferramentas. Esta pesquisa está sendo desenvolvida no LEPU (Laboratório de Ensino e Pesquisa em Usinagem) em parceria com o IPEN (Instituto de Pesquisas Energéticas e Nucleares), que disponibilizou um equipamento laser com pulsos da ordem de femtossegundos de frequência, ideal para garantir a qualidade das texturas. O trabalho também conta com a colaboração da Sandvik Coromant (ferramental), e Blaser (fluidos de corte). A metodologia consiste na execução de 3 etapas de experimentos, buscando otimizar as variáveis de entrada em cada etapa, para ser aplicada na etapa posterior. Dessa forma serão realizados um planejamento fatorial completo 24 (pré-testes com as variáveis de entrada selecionadas com base na literatura), seguido de um planejamento composto central 24 (para definir o ponto ótimo dos valores das variáveis de entrada) e por fim um fatorial completo 23 (para comparar a textura ótima com uma condição sem textura, acrescentando no estudo mais variáveis de saída). Atualmente a pesquisa está na fase de execução da segunda etapa. Neste trabalho é apresentado os resultados da primeira etapa. A presença de texturas reduziu as forças de usinagem e a rugosidade da peça em várias condições, indicando possíveis combinações para um ponto ótimo a ser estudado na segunda etapa. O mecanismo proveniente da interação entre textura e cavaco variou em diferentes faixas do avanço.
Síntese de silicatos de cálcio hidratados a partir de cinzas sulfatadas de carvão
2024 - ALCANTARA-DOMINGOS, RAQUEL R.; SANTOS, ANA C.C. dos R.; FUNGARO, DENISE A.
A geração de resíduos industriais pode causar diversos impactos ambientais se não forem destinados de maneira correta. Os compostos de silicato de cálcio hidratado (CSH), principalmente tobermorita, são componentes de matriz cimentícia. A síntese de compostos CSH foi realizada a partir de cinzas sulfatadas geradas no processo de dessulfurização dos gases da queima de carvão mineral por tratamento hidrotérmico alcalino. Os seguintes parâmetros que afetam a síntese foram avaliados: temperatura (180ºC e 200ºC) e tempo de síntese (6, 8, 10, 12 e 24 h). Os produtos obtidos foram caracterizados por fluorescência de raios-X (FRX) e difração de raios-X (DRX). Os componentes identificados em maior quantidade na cinza sulfatada por FRX foram Ca (26,3 %) e Si (22,2 %) apresentando que a razão desses elementos é favorável para a síntese de compostos CSH. Já, a composição de fase dos produtos examinada por DRX indicou que a intensidade relativa do pico principal da tobermorita, ou seja, a maior cristalinidade de CSH ocorreu no tempo de 8 h e temperatura de 200ºC. A utilização de resíduos gerados em grande quantidade para substituição parcial de cimento segue os princípios de sustentabilidade ambiental dentro dos objetivos de economia.
Kinetics study of Si release from silica synthesized from sugarcane waste ash
2024 - SANTOS, BARBARA J. dos; ULRICH, JOAO C.; FUNGARO, DENISE A.
Sugarcane bottom ash (SWA) is a byproduct generated in substantial quantities globally, creating significant environmental challenges due to inadequate disposal practices. This study focused on the extraction of high-purity silica from SWA using the sol-gel method, a process known for its efficiency in producing high-quality materials. Advanced characterization techniques, including X-ray fluorescence (XRF) and X-ray diffraction (XRD), confirmed the successful production of amorphous silica with a purity of 98%, demonstrating the effectiveness of this method. To further evaluate the Si content, the synthesized product underwent chemical treatment using a combination of citric acid, hydrochloric acid, and a salt mixture for a period of 48 h. This critical step improved the properties of the material and prepared it for further analysis. Kinetic parameters were determined to characterize the silicon release behavior under various conditions, providing valuable information on the potential of the material as a slow-release fertilizer. Four mathematical models—first-order equation, power function, parabolic diffusion, and Elovich model—were employed to describe the kinetics of Si release, providing insights into the product’s agricultural applications. The findings suggest that silica synthesized from SWA is not only a sustainable alternative to conventional fertilizers but also supports circular economy principles by transforming waste into valuable resources. Furthermore, this innovation aligns with the Sustainable Development Goals (SDGs) related to responsible consumption, production, and sustainable agriculture. By addressing environmental and agricultural challenges, this research highlights the dual benefits of waste management and resource efficiency. It demonstrates the role of innovative waste valorization strategies in promoting sustainability across industries and unlocking broader applications in the environmental and agricultural sectors, ultimately demonstrating the potential of SWA as a key resource in sustainable development.
Efeito da vegetação nas características do lixiviado de substrato de telhado verde
2024 - LIMA, DANIELE de A.V.; STELLATO, THAMIRIS B.; MONTEIRO, LUCILENA R.; FUNGARO, DENISE A.
Substrato é qualquer material usado com a finalidade de servir de base para o desenvolvimento de uma planta até sua transferência para o viveiro ou para a área de produção, podendo ser compreendido não apenas como suporte físico, mas também como fornecedor de nutrientes para a muda em formação. É um elemento essencial para o sucesso de um telhado verde, proporcionando um ambiente adequado para o desenvolvimento das plantas e contribuindo para os diversos benefícios que esses sistemas oferecem. A escolha criteriosa tanto do substrato, quanto das plantas, é fundamental para garantir a qualidade do escoamento pluvial e a capacidade de retenção de água do telhado verde. O objetivo desse trabalho foi analisar as propriedades do lixiviado produzido após contato de um substrato comercial com chuva ácida artificial na presença e ausência de vegetação. A grama amendoim foi selecionada nos experimentos. Os parâmetros analisados foram: propriedades químicas (pH e condutividade elétrica), propriedades hidráulicas (capacidade de retenção de água) e análise da capacidade de retenção de nutrientes. A presença da planta não influenciou o pH do lixiviado, com o valor médio de 6,6, maior do que da água de chuva. A capacidade de retenção de água dos substratos também não teve variação significativa com os valores médios faixa de 34 a 38%. No lixiviado da amostra de substrato com vegetação houve a redução da condutividade elétrica em 65% e a redução da concentração de nitrato, sulfato e fosfato em 95,5, 76,3 e 100%, respectivamente, consistente com a absorção de nutrientes pelas plantas e a estabilização do sistema radicular. Os resultados indicaram que o sistema substrato-planta do presente estudo apresentou potencial para ser usado em telhado verde.
Estudo comparativo da biocompatibilidade após tratamento de superfície com plasma kINPen IND® em amostras de policaprolactona (PCL)
2024 - GOMES, A.P.G.; DRIGO, E.; TADA, D.; CRUZ, N.C.; BOCK, E.G.P.
Sensitivity estimation for the future laser ionization diagnosis in inferring neutral particle density in the TCABR Tokamak
2024 - ALBUQUERQUE, FERNANDO A.F.; WETTER, NIKLAUS U.; SEVERO, JOSE H.F.
This study undertakes an estimation of photoionization occurrences and the ensuing reduction in hydrogen spectral line intensities via Laser-Induced Ionization. The objective is to quantify the sensitivity of the neutral particle density diagnostic.
São Paulo urban greenhouse gas network
2024 - DOMINGUES, LUCAS G.; ANDRADE, MARIA de F.; LANDULFO, EDUARDO; LEONARDO, NOELE; OLIVEIRA, CARLOS
Radon exhalation rate measurement in Amazon Forest soil
2024 - LAKIS, O.; MORALLES, M.; TAPPIZ, B.; OSTERMANN, C.K.; BUSTILLOS, J.O.V.; SILVA, P.S.C. da
Measurements of terrestrial residual gas emissions are important for investigations of atmospheric, biological, and geophysical processes. Terrestrial high-frequency flows of the radioactive noble gas ²²²Rn are useful for evaluating the performance of regional atmospheric models through the use of validated radon flux maps. In this sense, this work aims to validate a laboratory method for determining soil parameters that can influence the flow of ²²²Rn in samples collected at the Amazon Tall Tower Observatory (ATTO). Specifically, the pH and humidity values were determined for three soil types. Although more observations are still necessary, we concluded that, in comparison with works reported in the literature, the exhalation rate is in good agreement for tropical forest soils. However, no clear correlation could be observed between the ²²²Rn exhalation rate and soil humidity or pH.
Long-term isoprene (BVOC) fluxes in the Amazon Rainflorest by relaxed eddy accumulation coupled to GC/PID (REAPER)
2024 - OSTERMANN, CAROLINE; GUENTHER, ALEX; MARTIN, SCOT; WILLIAM, JONATHAN; FERRACCI, VALERIO; NAGALINGAM, SANJEEVI; WANG, HUI; KITTITANANUVONG, PITCHAYAWEE; LAA, ALVIN; ZANONI, NORA; DUVOISIN, SERGIO; NASCIMENTO, SILVANA; ALCINEI, FRANCISCO; SOUZA, RODRIGO; BUSTILLOS, OSCAR V.
Understanding the role of Biogenic Volatile Organic Compounds (BVOCs) in atmospheric chemistry and their impact on oxidants and aerosol formation is essential for global environmental research. BVOC emissions, primarily sourced from biogenic processes, pose a challenge due to the vast diversity of vegetation and ecosystems, as well as temporal changes in land use. While prevalent BVOC emission models categorize vegetation into functional types, the variability in environmental parameters and temporal fluctuations within natural canopies remains inadequately represented. This study introduces an innovative device system designed to address these challenges by integrating the Relaxed Eddy Accumulator and Gas Chromatograph Photoionization Detector (REAPER) in real-time measurement of isoprene fluxes. The system is portable, cost-effective and lightweight, easily to deploy in remote environments. By enabling high temporal resolution measurements, this device overcomes limitations associated with traditional techniques and offers accurate chromatograms. The novel instrument also facilitates real-time data transmission through a cloud-based platform, allowing access to meteorological data, calculated parameters, chromatograms and flux results. This feature supports the deployment of these systems across a wide range of sites and integrates them into existing flux tower networks. In conclusion, this research contributes to the advancement of isoprene fluxes measurement techniques and validation of satellite-based retrievals of isoprene abundances providing a valuable tool for scientists studying atmospheric chemistry and its impacts on the environment in diverse ecosystems, ultimately aiding in our understanding of the complex interplay between biogenic processes and atmospheric chemistry. The REAPER is installed in the ATTO tower in the Amazon rainforest and continuously measures Isoprene every hour within parts per billion (ppb) content. All the meteorology and chemistry data are sent through the Internet anywhere in the world to measure the BVOCs fluxes.
Carbon dioxide and methane levels in surface waters along the São Vicente island in coastal region of São Paulo state
2024 - ARAUJO, ELAINE C.; ANDRADE, IZABEL da S.; MACEDO, FERNANDA de M.; CORREA, THAIS; ANDRADE, THAIS; BRAGA, ELISABETE S.; ANDRADE, MARIA de F.; LANDULFO, EDUARDO
Various studies explore the relationship between the rising levels of CO2 and CH4 (greenhouse gasses) in the atmosphere and climate changes, and how these increases are connected to human activities. The escalation of these gas species may have implications for the environment. Concerning coastal systems, the rise in greenhouse gas emissions could impact the environment through multiple pathways because the atmosphere and superficial ocean waters also have significant exchanges. The main purpose of this work is to study Greenhouse gasses (GHG), such as CO2 and CH4, on the superficial waters of the coastal region of Sao Paulo coast. The data were collected in situ on a vessel provided by the Institute of Oceanography of Sao Paulo University (IOUSP). The campaign was conducted in spring 2022 (10 -11 October) in the south of the coast of Sao Paulo state, traveling through cities with anthropogenic impacts in principal Santos city, which is located the main port of Sul America. For these in situ measurements a portable gas analyzer Microportable Greenhouse Gas Analyzers (LGR-ICOS ™ GLA Series) - was used to detect the CO2 and CH4 spectra through the Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) technique.
Assembly results on GHG and particulated matter monitoring using low-cost sensors
2024 - SANTOS, JOSE C.; MATTA, JOSE A.S. da; LANDULFO, EDUARDO
Remoção de Sr2+ de solução aquosa usando zeólita A sintetizada a partir de cinzas de carvão e resíduo de alumínio
2024 - SANTOS, ANA C.C.R.; ULRICH, JOAO C.; DOMINGOS, RAQUEL R.A.; FUNGARO, DENISE A.

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