Determinação estatística dos contatos fluidos em perfis de poço

No interior dos reservatórios petrolíferos, o efeito da gravidade produz naturalmente a segregação dos fluidos presentes. Em razão basicamente das forças capilares não existe uma superfície definida de separação entre cada dois fluidos. No entanto, é comum na engenharia de petróleo admitir-se uma superfície convencional de separação dos fluidos. À essa superfície dá-se o nome de interface fluida ou contato fluido. A obtenção da localização dos contatos fluidos no interior dos reservatórios, como os contatos óleo-água, contatos gás-água e os contatos gás-óleo, sem a interpretação completa dos perfis geofísicos ou a realização dos procedimentos diretos dos testes de formação é um problema de difícil solução para a indústria do petróleo. O posicionamento em profundidade dos contatos pode ser utilizado para a definição dos procedimentos de completação do poço e para o posicionamento do canhoneio nos horizontes produtores dos poços verticais. Temos também a aplicação do mapeamento deste parâmetro, para os projetos e controle da perfuração no caso dos poços direcionais e horizontais, que utilizam tal informação para o posicionamento do eixo do poço no interior da zona de hidrocarboneto no reservatório, a fim de se evitar, principalmente, a produção de água. Este trabalho apresenta uma metodologia para a identificação e posicionamento dos contatos fluidos, através da aplicação da técnica da estatística multivariada, chamada de análise discriminante. Nesta aplicação, faz-se uso direto dos perfis de resistividade (R_T), de raios gama natural (RG), de densidade (ρ_b), de porosidade neutrônica (Φ_N), de caliper (Cal) e do perfil de volume de argila (Vcla), como dados de entrada no programa de análise discriminante. Para o caso de depósitos clásticos, com seqüências arenito-folhelho, a análise discriminante fornece ainda a indicação da litologia e as espessuras aparentes dos reservatórios. As curvas de perfis geofísicos aplicadas para a avaliação desta metodologia são provenientes de poços perfurados na bacia do lago Maracaibo, na Venezuela, onde, segundo estudos geológicos, existe a ocorrência de seqüências estratigráficas, com camadas de folhelhos e arenitos, sendo também confirmada a presença de hidrocarbonetos nos poços utilizados neste trabalho.

Resorption of roots of different dimension induced by different types of forces

Root resorption is a variable to be considered in induced tooth movement (ITM). It is related to root morphology and alveolar bone crest, and also to the types of forces exerted by mechanotherapy. This histometric study evaluated the predominance of root resorption among roots of different dimensions, following ITM with different types of forces and at different time intervals. The study was conducted on 54 rats divided into three groups, according to the type of force: continuous (CF), continuous interrupted (CIF) and intermittent (IF), at periods of 5, 7 and 9 days. The percentage of resorption between mesiobuccal roots of larger dimension and intermediate roots of smaller dimension was assessed. The evaluations were performed on the AxioVision software, and the non-parametric analysis of variance for repeated measures in independent groups was further applied, consisting of a scheme of two factors, and complemented by the Dunn test at a significance level of 5%. The intermediate roots presented a higher percentage of resorption, which was gradual at the periods evaluated for the three types of forces, but mainly for CF. Comparing the intermediate roots with the mesiobuccal roots, there was a statistically significant difference (p < 0.05) in the CF group at day 7 and day 9, and in the FI group, at day 9. The intragroup analysis evidenced a statistically significant difference (p < 0.05) between the 5th and the 9th day for the intermediate root in the CF group. The intergroup analysis did not reveal any statistically significant difference (p > 0.05) in individually analyzed roots.

Non-contact specular microscopy in aphakic and pseudophakic dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Implications of Surface and Bulk Properties of Abutment Implants and Their Degradation in the Health of Periodontal Tissue

The aim of the current review was to investigate the implications of the surface and bulk properties of abutment implants and their degradation in relation to periodontal health. The success of dental implants is no longer a challenge for dentistry. The scientific literature presents several types of implants that are specific for each case. However, in cases of prosthetics components, such as abutments, further research is needed to improve the materials used to avoid bacterial adhesion and enhance contact with epithelial cells. The implanted surfaces of the abutments are composed of chemical elements that may degrade under different temperatures or be damaged by the forces applied onto them. This study showed that the resulting release of such chemical elements could cause inflammation in the periodontal tissue. At the same time, the surface characteristics can be altered, thus favoring biofilm development and further increasing the inflammation. Finally, if not treated, this inflammation can cause the loss of the implant.

Contact parameters in two dimensions for general three-body systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of Different Conditions of Contact for Caprolactam Migration from Multilayer Polyamide Films into Food Simulants

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

On the contact stiffness and nonlinear vibration of an elastic body with a rough surface in contact with a rigid flat surface

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

C-l-contact and C-l-right equivalences of real semi-quasihomogeneous C-l function germs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thickness and marking quality of different occlusal contact registration strips

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

C^l-contact and C^l-right equivalences of real semi-quasihomogeneous C^l-function germs

In this paper we investigate the C ` versions of contact and right equivalences of real semi-quasihomogeneous C ` function germs, 1 ≤ ` ≤ ∞. The C ` -right equivalence implies C ` -contact equivalence for any 1 ≤ ` ≤ ∞ and in this work we show, up to certain conditions, that for semi-quasihomogeneous C ` function germs the converse is also true. As a consequence, we recover some known results about C∞-right and C∞-contact equivalences of C∞ function germs. We note that we are considering semi-quasihomogeneous function germs with no additional hypothesis of isolated singularity at zero.

Cytotoxicity of dimethyl sulfoxide (DMSO) in direct contact with odontoblast-like cells

To evaluate the cytotoxicity of dimethyl sulfoxide (DMSO) on the repair-related activity of cultured odontoblast-like MDPC-23 cells. Methods Solutions with different concentrations of DMSO (0.05, 0.1, 0.3, 0.5 and 1.0 mM), diluted in culture medium (DMEM), were placed in contact with MDPC-23 cells (5 × 104 cells/cm2) for 24 h. Eight replicates (n = 8) were prepared for each solutions for the following methods of analysis: violet crystal dye for cell adhesion (CA), quantification of total protein (TP), alizarin red for mineralization nodules formation (MN) and cell death by necrosis (flow cytometry); while twelve replicates (n = 12) were prepared for viable cell number (Trypan Blue) and cell viability (MTT assay). Data were analyzed by ANOVA and Tukey or Kruskal–Wallis and Mann–Whitney's tests (p < 0.05). Results Cell viability, adhesion and percentage of cell death by necrosis were not affected by DMSO at any concentration, with no statistical significant difference among the groups. A significant reduction in total protein production was observed for 0.5 and 1.0 mM of DMSO compared to the control while increased mineralized nodules formation was seen only for 1.0 mM DMSO. Significance: DMSO caused no or minor cytotoxic effects on the pulp tissue repair-related activity of odontoblast-like cells.

Bone-implant contact around crestal and subcrestal dental implants submitted to immediate and conventional loading

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Relationship between the surface chemical composition of implants and contact with the substrate

The purpose of the study was to use scanning electron microscopy and energy dispersive x-ray spectrometry to assess possible morphologic and chemical changes after performing double-insertion and pullout tests of implants of different shapes and surface treatments. Four different types of implants were used—cylindrical machined-surface implants, cylindrical double-surface–treated porous implants, cylindrical surface-treated porous implants, and tapered surface-treated porous implants—representing a total of 32 screws. The implants were inserted into synthetic bone femurs, totaling 8 samples, before performing each insertion with standardized torque. After each pullout the implants were analyzed by scanning electron microscopy and energy dispersive x-ray spectrometry using a universal testing machine and magnified 35 times. No structural changes were detected on morphological surface characterization, only substrate accumulation. As for composition, there were concentration differences in the titanium, oxygen, and carbon elements. Implants with surface acid treatment undergo greater superficial changes in chemical composition than machined implants, that is, the greater the contact area of the implant with the substrate, the greater the oxide layer change. In addition, prior manipulation can alter the chemical composition of implants, typically to a greater degree in surface-treated implants.

A clinical report of an oral lichen planus associated to epidermoid carcinoma in contact with metallic restorations

The aim of this study was to relate the clinical case of a patient with oral lichen planus (OLP) and a history of epidermoid carcinoma associated with metallic restorations. The etiology of OLP is a mucocutaneous disease, which is poorly understood. Studies point to the potential of malignant transformation of OLP and its association with metallic restorations. The metallic restorations were replaced by crowns with a ceramic covering associated and osseointegrated implants in the edentulous areas. About 1 year later, it was observed a bilateral regression of the tongue lesions. The replacement of metallic restorations can contribute to improvement of OLP.