Analysis of etching at a solid-solid interface

Alves, Washington S.,Rodrigues, Evandro A.,Fernandes, Henrique A.,Mello, Bernardo A.,Oliveira, Fernando A.,Costa, Ismael V. L. American Physical Society 2016 Physical review. E Vol.94 No.4

Epigallocatechin-3-gallate prior to composite resin in abfraction lesions: a split-mouth randomized clinical trial

Alves Luísa Valente Gotardo Lara,Fracasso Lisiane Martins,Cortez Thiago Vinicius,Souza-Gabriel Aline Evangelista,Corona Silmara Aparecida Milori 대한치과보존학회 2023 Restorative Dentistry & Endodontics Vol.48 No.2

Objectives Natural extracts have been investigated as a biomimetic strategy to mechanically strengthen the collagen network and control the biodegradation of extracellular matrix. This study evaluated the effect of epigallocatechin-3-gallate (EGCG) on abfraction lesions prior to the composite resin. Materials and Methods The sample consisted of 30 patients (aged between 28 and 60 years) with abfraction lesions located in 2 homologous premolars. The teeth were randomly assigned according to dentin treatment: 0.02% EGCG solution or distilled water (control). After enamel acid etching, the solutions were applied immediately for 1 minute. The teeth were restored with Universal Adhesive (3M) and Filtek Z350 XT (3M). Analyzes were done by 2 independent examiners using modified USPHS (retention, secondary caries, marginal adaptation, and postoperative sensitivity) and photographic (color, marginal pigmentation, and anatomical form) criteria at baseline (7 days) and final (18 months). The data analysis used Friedman and Wilcoxon signed-rank tests (α = 0.05). Results At baseline, all restorations were evaluated as alpha for all criteria. After 18 months, restorations were evaluated as alpha for secondary caries, color, and marginal pigmentation. There was significant difference between baseline and 18 months (p = 0.009) for marginal adaptation and postoperative sensitivity (p = 0.029), but no significant difference were verified between treatments (p = 0.433). The EGCG group had a restoration retention rate of 93.3%, while the control group had 96.7%. Conclusions The application of EGCG solution on abfraction lesions did not significantly influence the survival of the restorations based on clinical and photographic criteria. Objectives Natural extracts have been investigated as a biomimetic strategy to mechanically strengthen the collagen network and control the biodegradation of extracellular matrix. This study evaluated the effect of epigallocatechin-3-gallate (EGCG) on abfraction lesions prior to the composite resin. Materials and Methods The sample consisted of 30 patients (aged between 28 and 60 years) with abfraction lesions located in 2 homologous premolars. The teeth were randomly assigned according to dentin treatment: 0.02% EGCG solution or distilled water (control). After enamel acid etching, the solutions were applied immediately for 1 minute. The teeth were restored with Universal Adhesive (3M) and Filtek Z350 XT (3M). Analyzes were done by 2 independent examiners using modified USPHS (retention, secondary caries, marginal adaptation, and postoperative sensitivity) and photographic (color, marginal pigmentation, and anatomical form) criteria at baseline (7 days) and final (18 months). The data analysis used Friedman and Wilcoxon signed-rank tests (α = 0.05). Results At baseline, all restorations were evaluated as alpha for all criteria. After 18 months, restorations were evaluated as alpha for secondary caries, color, and marginal pigmentation. There was significant difference between baseline and 18 months (p = 0.009) for marginal adaptation and postoperative sensitivity (p = 0.029), but no significant difference were verified between treatments (p = 0.433). The EGCG group had a restoration retention rate of 93.3%, while the control group had 96.7%. Conclusions The application of EGCG solution on abfraction lesions did not significantly influence the survival of the restorations based on clinical and photographic criteria.

SPIF-A: on the development of a new concept of incremental forming machine

Alves de Sousa, R.J.,Ferreira, J.A.F.,Sa de Farias, J.B.,Torrao, J.N.D.,Afonso, D.G.,Martins, M.A.B.E. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.5

This paper presents the design and project of an innovative concept for a Single Point Incremental Forming (SPIF) Machine. Nowadays, equipment currently available for conducting SPIF result mostly from the adaptation of conventional CNC machine tools that results in a limited range of applications in terms of materials and geometries. There is also a limited market supply of equipment dedicated to Incremental Sheet Forming (ISF), that are costly considering low batches, making it unattractive for industry. Other factors impairing a quicker spread of SPIF are large forming times and poor geometrical accuracy of parts. The following sections will depict the development of a new equipment, designed to overcome some of the limitations of machines currently used, allowing the development of a sounding basis for further studies on the particular features of this process. The equipment here described possesses six-degrees-of freedom for the tool, for the sake of improved flexibility in terms of achievable tool-paths and an extra stiffness provided by a parallel kinematics scheme. A brief state of the art about the existing SPIF machines is provided to support the project's guidelines.

Prediction of the dynamic flow stress

Alves, Marcilio Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.5

This article explores a constitutive equation that is able to correlate stress, strain and strain rate. In order to show the advantages of the constitutive equation here proposed and how its material parameters are obtained, data extracted from the literature, for materials as different as polymers and metallic alloys, are used. Finite element simulation of the impact behaviour of a beam is presented to highlight the care one needs to exercise when using the more traditional Cowper-Symonds equation. The present constitutive equation has shown to be accurate for a wide range of strains, stresses and strain rates.

Methodologies for the Determination of Endogenous Phosphorus Losses in Growing Pigs

Alves, Debora Aline,da Rocha, Leonardo Tombesi,dos Santos Camargo, Claudiele Aparecida,Figueiredo, Andriele Medianeira,Ceron, Marcos Speroni,Lucca, Walter,Zanella, Irineo,de Oliveira, Vladimir Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.11

A study was conducted to compare the endogenous basal losses of phosphorus (EBLP) in pigs fed diets containing gelatin (GEL) or spray-dried porcine plasma (SDPP) as protein sources and to determine the standardized total tract digestibility (STTD) of phosphorus (P) in SDPP. The trial was carried out at the Federal University of Santa Maria, Brazil. Twelve castrated pigs with an initial body weight of 55 kg were individually allotted in metabolic crates during two 12-day periods, each with 7 days of adaptation and 5 days of total fecal collection. The beginning and the end of the collecting periods were determined according to the marker-to-marker approach, using ferric oxide as an indigestible marker. Pigs were submitted to four semi-purified diets, one being a P-free diet with 30% of GEL as the protein source and three were diets with 10%, 20%, and 30% inclusion of SDPP respectively. Data were subjected to analysis of variance and the model included the effects of period, animal and treatments; the results of the three diets with increased levels of SDPP were subjected to linear regression analysis. The intercept of the relation of between ingested P and absorbed P represented the EBLP, while the slope indicated the STTD of P in SDPP. The EBLP means obtained by P-free diet and regression method were compared with the Student t test. The EBLP were 128.95 mg/kg dry matter intake (DMI) and 153.63 mg/kg DMI (standard error = 77.0; p<0.06) using the P-free diet with GEL as the protein source and the regression method, obtained with diets containing increased levels of SDPP, respectively. The apparent digestibility of P was 87.9%, 94.2%, and 92.9% for the treatments containing 10%, 20%, and 30% inclusion of SDPP, respectively. The estimated STTD of P obtained with the linear regression was 97.4%. When the EBLP estimated by the P-free diet was used to corrected the apparent digestibility of P in diets containing SDPP, the STTD of P in SDPP was 96.9%, 98.8%, and 95.9% for 10%, 20%, and 30% SDPP, respectively. Therefore, it can be concluded that SDPP can replace GEL to estimate the endogenous losses of P. In addition, the STTD of P in SDPP estimated with the P-free diet was 97.2% and it was 97.4% by the regression method, utilizing SDPP.

Implications of strong intergalactic magnetic fields for ultrahigh-energy cosmic-ray astronomy

Alves Batista, Rafael,Shin, Min-Su,Devriendt, Julien,Semikoz, Dmitri,Sigl, Guenter American Physical Society 2017 Physical review. D Vol.96 No.2

<P>We study the propagation of ultrahigh-energy cosmic rays in the magnetized cosmic web. We focus on the particular case of highly magnetized voids (B similar to nG), using the upper bounds from the Planck satellite. The cosmic web was obtained from purely magnetohydrodynamical cosmological simulations of structure formation considering different power spectra for the seed magnetic field in order to account for theoretical uncertainties. We investigate the impact of these uncertainties on the propagation of cosmic rays, showing that they can affect the measured spectrum and composition by up to. similar or equal to 80% and. similar or equal to 5%, respectively. In our scenarios, even if magnetic fields in voids are strong, deflections of 50 EeV protons from sources closer than similar to 50 Mpc are less than 15 degrees in approximately 10-50% of the sky, depending on the distribution of sources and magnetic power spectrum. Therefore, UHECR astronomy might be possible in a significant portion of the sky depending on the primordial magnetic power spectrum, provided that protons constitute a sizeable fraction of the observed UHECR flux.</P>

Prediction of the dynamic flow stress

Marcilio Alves 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.5

Malignant Posterior Reversible Encephalopathy Syndrome: A Case of Posterior Irreversible Encephalopathy Syndrome

William Alves Martins,Luiz Carlos Porcello Marrone 대한신경과학회 2016 Journal of Clinical Neurology Vol.12 No.2

Collective laser‐assisted bonding process for 3D TSV integration with NCP

Wagno Alves Braganca Junior,엄용성,장건수,문석환,배현철,최광성 한국전자통신연구원 2019 ETRI Journal Vol.41 No.3

Laser‐assisted bonding (LAB) is an advanced technology in which a homogenized laser beam is selectively applied to a chip. Previous researches have demonstrated the feasibility of using a single‐tier LAB process for 3D through‐silicon via (TSV) integration with nonconductive paste (NCP), where each TSV die is bonded one at a time. A collective LAB process, where several TSV dies can be stacked simultaneously, is developed to improve the productivity while maintaining the reliability of the solder joints. A single‐tier LAB process for 3D TSV integration with NCP is introduced for two different values of laser power, namely 100 W and 150 W. For the 100 W case, a maximum of three dies can be collectively stacked, whereas for the 150 W case, a total of six tiers can be simultaneously bonded. For the 100 W case, the intermetallic compound microstructure is a typical Cu‐Sn phase system, whereas for the 150 W case, it is asymmetrical owing to a thermogradient across the solder joint. The collective LAB process can be realized through proper design of the bonding parameters such as laser power, time, and number of stacked dies.

Processing and Characterization of Chitosan Films with Incorporation of Ethanolic Extract from “Pequi” Peels

Caroline Alves Breda,Daniella Lury Morgado,Odílio Benedito Garrido Assis,Marta Cristina Teixeira Duarte 한국고분자학회 2017 Macromolecular Research Vol.25 No.11

Chitosan is a polysaccharide with excellent film forming ability widely evaluated as active packaging and edible coatings. Chitosan has good antimicrobial activity in gel form; however, in a solid state (film format), a reduction in this activity can occur due to spatial arrangement of the chains in the polymer matrix. Small amounts of natural compounds could then be added to the film formulations to improve both antifungal and antibacterial properties. One possible additive is the “pequi” (Caryocar brasiliense Comb.) peel ethanolic extract (PPE), which forms homogenous blend with chitosan and has proved antimicrobial activity. In this study the preparation of chitosan-PPE was evaluated concerning the effect promoted in the film structure due PPE incorporation. Films processed by casting were analyzed by Fourier transform infrared spectroscopy (FTIR), microscopy, X-ray diffraction, mechanical and thermal properties, water vapor permeability (WVP) and surface wettability. FTIR analysis indicates interactions between the phenolic compounds in the extract and the hydroxyl and amine groups present in the chitosan structure, by establishing a possible ester bonding between constituents. The presence of PPE resulted in a decrease of WVP and an increasing in hydrophobicity. The extract addition also reduced the film’s crystallinity along with a slight decrease of plasticity and lowering of the initial polymeric degradation temperature. However, the blend was characterized by a homogeneous matrix with smooth topography. The results suggest that PPE has good compatibility with chitosan, introducing small changes that do not alter the potential for medical or foodstuff applications.