Thomaz Jacintho Lopes

Mr. Thomaz Jacintho Lopes

orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 April 2025 in Polymers
Verified
Journal Article
Open access
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AAAry Machado de Azevedo
Ary Machado de Azevedo
Pedro Henrique Poubel Mendonça da SilveiraPedro Henrique Poubel Mendonça da Silveira
Pedro Henrique Poubel Mendonça da Silveira
TLThomaz Jacintho Lopes
Thomaz Jacintho Lopes
OCOdilon Leite Barbosa da Costa
Odilon Leite Barbosa da Costa
Sergio Neves MonteiroSergio Neves Monteiro
Sergio Neves Monteiro
André Ben-Hur da FigueiredoAndré Ben-Hur da Figueiredo
André Ben-Hur da Figueiredo
This article explores the foundational principles of ionizing radiation and provides a comprehensive overview of its impact on thermoplastic polymers. Ionizing radiation, encompassing gamma rays, X-rays, and electron beams, has been extensively studied due to its capacity to alter the molecular structure of polymers. These changes enable advancements in various applications by promoting molecular crosslinking, controlled degradation, molecular grafting, and crystallinity adjustments. The article delves into the fundamental mechanisms of radiation thermoplastic polymer interactions, including ionization, electronic excitation, and free radical formation. It highlights how these processes lead to structural transformations that enhance the physical, thermal, and mechanical properties of thermoplastic polymers. Factors such as radiation type, absorbed doses, temperature, and environmental conditions are discussed in the context of their role in controlling these modifications. Key practical applications are identified across fields such as medicine, food packaging, aerospace, and industry. Examples include the production of sterilizable medical devices, enhanced food packaging for longer shelf life, and radiation-resistant materials for the aerospace and nuclear sectors. Despite its many advantages, the article also emphasizes challenges such as process variability, polymer sensitivity to radiation, and standardization difficulties. The review underscores emerging research directions, including optimizing irradiation parameters and integrating advanced characterization techniques like Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray diffraction (XRD). The development of new polymer blends and composites, designed for irradiation-induced property enhancement, represents a promising area of innovation.

15 August 2025 in Journal of Composites Science
Verified
Journal Article
Open access
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TLThomaz Jacintho Lopes
Thomaz Jacintho Lopes
AAAry Machado de Azevedo
Ary Machado de Azevedo
Sergio Neves MonteiroSergio Neves Monteiro
Sergio Neves Monteiro
FAFernando Manuel Araujo-Moreira
Fernando Manuel Araujo-Moreira
Conductive composites are a flexible class of engineered materials that combine conductive fillers with an insulating matrix—usually made of ceramic, polymeric, or a hybrid material—to customize a system’s electrical performance. By providing tunable electrical properties in addition to benefits like low density, mechanical flexibility, and processability, these materials are intended to fill the gap between conventional insulators and conductors. The increasing need for advanced technologies, such as energy storage devices, sensors, flexible electronics, and biomedical interfaces, has significantly accelerated their development. The electrical characteristics of composite materials, including metallic, ceramic, polymeric, and nanostructured systems, are thoroughly examined in this review. The impact of various reinforcement phases—such as ceramic fillers, carbon-based nanomaterials, and metallic nanoparticles—on the electrical conductivity and dielectric behavior of composites is highlighted. In addition to conduction models like correlated barrier hopping and Debye relaxation, the study investigates mechanisms like percolation thresholds, interfacial polarization, and electron/hole mobility. Because of the creation of conductive pathways and improved charge transport, developments in nanocomposite engineering, especially with regard to graphene derivatives and silver nanoparticles, have shown notable improvements in electrical performance. This work covers the theoretical underpinnings and physical principles of conductivity and permittivity in composites, as well as experimental approaches, characterization methods (such as SEM, AFM, and impedance spectroscopy), and real-world applications in fields like biomedical devices, sensors, energy storage, and electronics. This review provides important insights for researchers who want to create and modify multifunctional composite materials with improved electrical properties by bridging basic theory with technological applications.

2 December 2024 in OBSERVATÓRIO DE LA ECONOMÍA LATINOAMERICANA
Verified
Journal Article
Open access
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AAAry Machado de Azevedo
Ary Machado de Azevedo
TLThomaz Jacintho Lopes
Thomaz Jacintho Lopes
DCDomingos D’oLiveira Cardoso
Domingos D’oLiveira Cardoso
Sergio Neves MonteiroSergio Neves Monteiro
Sergio Neves Monteiro
PSPaulo Cezar Rocha Silveira
Paulo Cezar Rocha Silveira
André Ben-Hur da FigueiredoAndré Ben-Hur da Figueiredo
André Ben-Hur da Figueiredo
This review addresses the application of silicon-germanium (SiGe) semiconductors as electronic components, highlighting their enhanced electronic and physical properties compared to pure silicon semiconductors. SiGe Semiconductors are widely used in high-performance devices, such as heterojunction bipolar transistors (HBTs) and radio-frequency integrated circuits (RFICs), due to their ability to improve speed, efficiency, and overall device performance. Incoporating Ge into Si increases electron mobility, enabling devices to operate at higher speeds and with lower power consumption, which is crucial for portable and low-power applications. Additionally, SiGe semiconductors are compatible with existing Si semiconductor manufacturing processes, facilitating their integration into complementary metal-oxide semiconductor (CMOS) technologies. Another significant benefit is their improved high-frequency performance, making them suitable for applications such as wireless communications and radar technologies. By varying the Ge composition in SiGe, it is possible to adjust the bandgap and lattice strain, providing flexibility in the design of electronic and optoelectronic devices. These attributes make SiGe semiconductors an ideal choice for a wide range of advanced applications where performance and energy efficiency are essential.

8 April 2026 in Polymers
Verified
Journal Article
Open access
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Douglas Santos SilvaDouglas Santos Silva
Douglas Santos Silva
RJRaí Felipe Pereira Junio
Raí Felipe Pereira Junio
EBElias Matias Bentes
Elias Matias Bentes
TLThomaz Jacintho Lopes
Thomaz Jacintho Lopes
BMBelayne Zanini Marchi
Belayne Zanini Marchi
Sergio Neves MonteiroSergio Neves Monteiro
Sergio Neves Monteiro
This study investigates the ballistic performance and energy dissipation mechanisms of epoxy composites reinforced with raffia fabric at fiber volume fractions of 10%, 20%, and 30% under 9 mm full metal jacket projectile impact. Ballistics tests were conducted to determine impact and residual velocities, absorbed energy, absorption efficiency, equivalent ballistic limit, and momentum reduction. All tests were performed at similar impact velocities (≈433 m/s), corresponding to an incident energy of approximately 750 J. The results revealed a clear inverse relationship between raffia content and energy absorption capability. The ER10 composite exhibited the highest performance, with an absorbed energy of 176.7 ± 9.7 J, absorption efficiency of 23.5 ± 0.9%, and momentum reduction of 0.1253 ± 0.0053. Increasing the fiber fraction to 20% (ER20) and 30% (ER30) led to progressive reductions in absorbed energy to 119.7 ± 2.7 J and 77.7 ± 9.0 J, with efficiencies of 15.95 ± 0.26% and 10.30 ± 1.12%, respectively. The residual velocity increased from 379.3 ± 2.5 m/s (ER10) to 397.0 ± 2.1 m/s (ER20) and 411.1 ± 1.6 m/s (ER30). One-way ANOVA detected statistically significant differences in absorbed energy and absorption efficiency among the different fiber volume fractions (p < 0.001). The results demonstrate a trade-off between stiffness and toughness and indicate that raffia-reinforced composites can play complementary roles in sustainable multilayered armor systems.

1 July 2024 in OBSERVATÓRIO DE LA ECONOMÍA LATINOAMERICANA
Verified
Journal Article
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AAAry Machado de Azevedo
Ary Machado de Azevedo
TLThomaz Jacintho Lopes
Thomaz Jacintho Lopes
JSJoana Batista Soares
Joana Batista Soares
MMMarcos Paulo Cavaliere de Medeiros
Marcos Paulo Cavaliere de Medeiros
FAFernando M. Araujo-Moreira
Fernando M. Araujo-Moreira
André Ben-Hur da FigueiredoAndré Ben-Hur da Figueiredo
André Ben-Hur da Figueiredo
This work investigated the impact of doping Stainless Steel 316 with silicon carbide (SiC) nanoparticles on the performance of nuclear fuel through computational simulations using the MCNP5 software. The results indicated that the addition of SiC did not significantly affect the effective multiplication factor (keff), suggesting that this doping may be a viable strategy to improve fuel properties without compromising its effectiveness. Additionally, the inclusion of SiC may offer additional benefits such as increased thermal stability and corrosion resistance. These findings highlight the potential of SiC as a promising additive for the development of safer and more efficient fuel elements in nuclear reactors, paving the way for future research and innovations in the field of nuclear energy.

3 September 2024 in OBSERVATÓRIO DE LA ECONOMÍA LATINOAMERICANA
Verified
Journal Article
Open access
PDF file
TLThomaz Jacintho Lopes
Thomaz Jacintho Lopes
AAAry Machado de Azevedo
Ary Machado de Azevedo
JSJoana Batista Soares
Joana Batista Soares
MMMarcos Paulo Cavaliere de Medeiros
Marcos Paulo Cavaliere de Medeiros
DCDomingos D’oliveira Cardoso
Domingos D’oliveira Cardoso
FAFernando M. Araujo-Moreira
Fernando M. Araujo-Moreira
In this study, the importance of simulations conducted in MCNP5 and the modifications implemented in 316 steel to optimize energy efficiency in nuclear power production are explored. Graphene are investigated as promising additives due to their low absorption cross-section for thermal neutrons, which facilitates a more significant participation of neutrons in fission and heat generation. Through the use of the MCNP5 code, simulations were conducted to analyze a hypothetical UO2 fuel element with different enrichment zones to evaluate its performance. The results highlight that the inclusion of graphene in the fuel cladding alloy has a significant impact on neutron production, suggesting that this addition may compromise energy generation efficiency. In summary, this study emphasizes the potential of graphene s as additives to enhance nuclear fuel performance, promoting safer, more efficient, and sustainable nuclear energy.