The potential of novel primers and universal adhesives to bond to zirconia

Objectives: To investigate the adhesive potential of novel zirconia primers and universal adhesives to surface-treated zirconia substrates.Methods: Zirconia bars were manufactured (3.0 mm x 3.0 mm x 9.0 mm) and treated as follows: no treatment (C); air abrasion with 35 mu m alumina particles (S); air abrasion with 30 mu m silica particles using one of two systems (Rocatec or SilJet) and; glazing (G). Groups C and S were subsequentially treated with one of the following primers or adhesives: ZP (Z-Prime Plus), AZ (AZ Primer); MP (Monobond Plus); SU (ScotchBond Universal) and; EA (an Experimental Adhesive). Groups Rocatec and SilJet were silanized prior to cementation. Samples form group G were further etched and silanized. Bars were cemented (Multilink) onto bars of a silicate-based ceramic (3.0 mm x 3.0 mm x 9.0 mm) at 90 degrees angle, thermocycled (2.500 cycles, 5-55 degrees C, 30 s dwell time), and tested in tensile strength test. Failure analysis was performed on fractured specimens to measure the bonding area and crack origin.Results: Specimens from group C did not survive thermocycling, while CMP, CSU and CEA groups survived thermocycling but rendered low values of bond strength. All primers presented a better bond performance after air abrasion with Al2O3 particles. SilJet was similar to Rocatec, both presenting the best bond strength results, along with SMP, SSU and CEA. G promoted intermediate bond strength values. Failure mode was predominately adhesive on zirconia surface combined to cohesive of the luting agent.Conclusions: Universal adhesives (MP, SU, EA) may be a considerable alternative for bonding to zirconia, but air abrasion is still previously required. Air abrasion with silica particles followed by silane application also presented high bond strength values. (C) 2013 Elsevier Ltd. All rights reserved.

Zirconia-Porcelain Bonding: Effect of Multiple Firings on Microtensile Bond Strength

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

Strength of 3Y-TZP and feldspathic porcelain subjected to different cooling methods

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

Diagnóstico do estado geoambiental da área urbana do município de Cubatão (SP)

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

Estudo dos efeitos do LiNO3 na reação Álcali-Sílica e comparação com os efeitos da cinza volante na reação

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

Análise dinâmica de mecanismo articulado de suspensão com não-linearidade na rigidez devido à geometria e à excitação por desbalanceamento rotativo na condição não ideal

Pós-graduação em Engenharia Mecânica - FEB

Effects of aging procedures on the topographic surface, structural stability, and mechanical strength of a ZrO2-based dental ceramic

Objective. To determine the effects of different aging methods on the degradation and flexural strength of yttria-stabilized tetragonal zirconia (Y-TZP)Methods. Sixty disc-shaped specimens (0, 12 mm; thickness, 1.6 mm) of zirconia (Vita InCeram 2000 YZ Cubes, VITA Zahnfabrik) were prepared (ISO 6872) and randomly divided into five groups, according to the aging procedures (n=10): (C) control; (M) mechanical cycling (15,000,000 cycles/3.8 Hz/200N); (T) thermal cycling (6,000 cycles/5-55 degrees C/30 s); (TM) thermomechanical cycling (1,200,000 cycles/3.8 Hz/200N with temperature range from 5 C to 55 C for 60s each); (AUT) 12h in autoclave at 134 degrees C/2 bars; and (STO) storage in distilled water (37 degrees C/400 days). After the aging procedures, the monoclinic phase percentages were evaluated by X-ray diffraction (XRD), and topographic surface analysis was performed by 3D profilometry. The specimens were then subjected to biaxial flexure testing (1 mm/min, load 100 kgf, in water). The biaxial flexural strength data (MPa) were analyzed by 1-way ANOVA and Tukey's test (alpha = 0.05). The data for monoclinic phase percentage and profilometry (Ra) were analyzed by Kruskal-Wallis and Dunn's tests.Results. ANOVA revealed that flexural strength was affected by the aging procedures (p = 0.002). The M (781.6 MPa) and TM (771.3 MPa) groups presented lower values of flexural strength than did C (955 MPa), AUT (955.8 MPa), T (960.8 MPa) and STO (910.4 MPa). The monoclinic phase percentage was significantly higher only for STO (12.22%) and AUT (29.97%) when compared with that of the control group (Kruskal-Wallis test, p = 0.004). In addition, the surface roughnesses were similar among the groups (p = 0.165).Signcance. Water storage for 400 days and autoclave aging procedures induced higher phase transformation from tetragonal to monoclinic; however, they did not affect the flexural strength of Y-TZP ceramic, which decreased only after mechanical and thermomechanical cycling. (C) 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Análise da dinâmica de ocupação e uso das terras e suas implicações no sistema morfohidrográfico da Bacia do Ribeirão Bonito-SP

Os sistemas ambientais são compostos por elementos e atributos que atuam em sua dinâmica, os quais, ao longo de um dado período de tempo, podem responder às condições naturais ou às imposições antrópicas, sendo que estas últimas podem desencadear modificações no seu equilíbrio natural. Neste contexto, o objetivo principal do trabalho proposto foi identificar e analisar as alterações na dinâmica de ocupação e uso das terras e sua interferência nas características naturais da bacia do Ribeirão Bonito – SP, com ênfase à geomorfologia e hidrografia. A área em questão situa-se junto à baixa bacia do Rio Piracicaba, no Estado de São Paulo, numa área de transição entre a Depressão Periférica Paulista e as Cuestas Basálticas. Para a consolidação do objetivo proposto foram utilizados os seguintes procedimentos metodológicos: revisão de literatura referente à temática adotada; caracterização do meio físico e do processo de ocupação da área em estudo; elaboração de mapas geomorfológicos de dois cenários (1962 e 2007) de acordo com as metodologias de Tricart (1965) e Verstappen; Zuidan (1975), adaptados por Cunha (2001); elaboração de mapas de ocupação e uso das terras dos dois períodos (1962 e 2007) utilizando o sistema de classificação do IBGE (2006b) e trabalhos de campo. Para manuseio dos dados e posterior análise dos mesmos, foi utilizada a idéia de sistema ambiental, que se fundamenta na teoria dos sistemas gerais, aplicada a Geografia. Findados os levantamentos, observou-se que o aumento do nível de base local com conseqüente retomada erosiva, assim como a intensa ocupação das terras pela cultura da cana-de-açúcar, foram fatores que condicionaram as alterações geomorfológicas locais, expressas principalmente pela dinâmica erosiva e processos de denudação

Caracterização geológica do perfil laterítico no município de Rondon do Pará, bloco sul do projeto Alumina Rondon

This completion of course work has as its object of study the Bauxite Province of Paragominas regarded as the richest Amazon bauxite province and whose genesis is related to laterization processes responsible for the formation of mineral deposits of the Rondon Alumina Project, designed to assess areas in the southeast of Pará State, for mineral resources exploration of bauxite, which is the main source of aluminum in the country. Located in the region of Rondon do Pará - PA, the study area is geologically inserted in Lithostratigraphic Unit called Cobertura Laterítica Matura (Mature Lateritic Cover), formed by alteration of paleotropics Cretaceous siliciclastic rocks, and its geomorphology corresponds to a broad plateau with displays of representative profiles of the processes that acted in the region. In this context, the present research aims to characterize the geological evolution of the laterite profile, with detailed studies in the area, geological description of the formations from the bauxite surfaces, and mineralogical composition litochemical of different horizons that were correlated and deployed in an evolutionary model compatible with its traits. The data collected during the analysis subsidized metalogenetic understanding of the processes that acted in the enrichment of aluminum and iron as well as the redistribution of the latter modified profile. The results and information were embodied in the form of geological characterization of the different constituents of mineral associations of bauxite horizons, similarities or differences in both textural and structural aspects, in order to propose a evolutionary model with retaken of gibbsitization processes

Fácies e associação de fácies da formação Pirambóia na região de Descalvado/SP

The Pirambóia Formation is a lithostratigraphic unit of the Paraná Basin, positioned between the Corumbataí (lower) and Botucatu (upper) Formations on the eastern edge of the basin. This unit is focused by many studies due to its great importance as an essential component in the Guarani Aquifer System (SAG) and the petroleum system “Irati-Pirambóia”, as excellent reservoirs. The Pirambóia Formation is historically the subject of several controversies on issues like age, contact relationships with the upper unit and depositional paleoenvironment. Despite these aspects, the Pirambóia Formation is commonly taken to be of Triassic age and is considered a product of wet aeolian systems, with plenty of wet interdunes and subordinate fluvial facies. In this work, by using techniques such as facies analysis, depositional architecture and facies association, facies of this unit were characterized and their depositional paleoenvironment was inferred particularly in Jundu Mining, region of Descalvado in northeastern São Paulo. Techniques such as grain size and petrographic analyses, aimed to characterize this unit as a potential reservoir rock. Five facies were described for the Pirambóia Formation in the studied region: St, Sh, Sm, Sr and Gt facies, generated by sedimentary processes of the bottom load type, mostly under low flow regime (with exception for the Sh facies, which is formed by upper flow regime processes). In addition to that, four facies associations were recognized from the architectural elements, primarily contained within the main channel: complex channel bars, composed by foreset macroforms (FM), sandy bedforms (SB) and gravel bars and bedforms (GB); flood deposits, constituted by laminated sand sheets (LS); deposits of hyperconcentrated flows and eolian deposits. It was interpreted that the Pirambóia Formation in Descalvado (SP) is the record of the sedimentation of braided rivers, with dunes and interdunes deposits...

Ecologia de cultivos: caracterização dos aspectos ecológicos dos diferentes cultivos no município de Cristais Paulistas-SP

Planning is an essential instrument for the agricultural occupation of the lands, because it supports the activities of food production and raw materials. It must be driven by techniques that provide the sustainability of these activities, so that also ensures the environmental balance of agroecosystems. Lands misuse can be considered as one of the causes of frustration of agricultural activities. Thus, the occurrence of discrepancies between the effective use (real use) of the land and its agricultural aptitude can compete, in many cases, to the decrease of productivity, as well as for soil degradation. In this way, this research intends to study the relationship between the temporary cultivations, halfperennial cultures, perennial and its developmental environment, determining the edaphoclimatic characteristics of landscapes. From then on, a letter shall be subject to the use and occupation of the soil for agriculture in the municipality of Cristais Paulista-SP, aiming to describe the spatial organization of land use and vegetation cover, and emphasizing management and conservative practices. For that, climatic factors were characterized, fundamentally humidity, temperature and luminosity; edaphics, including parental material, chemical and physical properties, fertility, soil temperature and climatic zoning; biotic, referring to the suitability of different cultures or to be implanted; physical, such as geomorphology, slope, geology, hypsometry and hydrology; socioeconomic, in particular production and marketing seasons; and the way they all, together, affect the adaptation, distribution and production of crops. Using this information, the zoning of the area of study was done based on the 21 nominated groups obtained, in addition to recommendations and suggestions for handling each type of cultivation... (Complete abstract click electronic access below)

Redução de empeno em barra trefiladas do aço SAE 9254

In this paper we study the process of manufacture of wire drawn steel bars 9254, from rolled wire rod. These bars are used in the automotive industry for the manufacture of coil springs, which make up the system damping of several vehicles. The wire drawing process consists of the steps of pre-straightening, shot peening, drawing, cutting and polishing. The study aims to search for the configuration of process variables, which present the best result with respect to bending. To this were maintained settings prestraightening and mechanical stripping and varied angles and stringer polish being studied to replace the spinneret with a working angle, for a string with two working angles. To assist in the analysis of the results was the tool used DOE Software Minitab, which assesses the variation in results according to each parameter and the interaction parameters. It was thus possible to determine the best condition for wire drawing

Diagnóstico antropogeomorfológico em bacia hidrográfica urbana: o caso do Córrego do Jardim São João, Araras (SP)

Man can transform the nature according to their needs through technique which enables agriculture, cattle raising, constructions of buildings for housing, transport routes, etc. This action has brought significant transformations to the environment, and relief is one of the most changed elements, mainly at urban areas, which concentrates most of the Brazilian population. In these areas geomorphologic systems have undergone alterations in their flow of matter and energy by the action of man. Thus, it is possible o understand the action of man as geomorphologic action, nowadays, the tecnógeno, since the human action can interfere qualitatively and quantitatively in the input and output of these systems. The anthropic geomorphology has contributed to the analyses of the effects due to the urbanization at the form and at the geomorphologic process in the urban watersheds, indicating the transformations at the shape of the relief and the alterations due to the acceleration of the flow of matter and energy. From these questions, this study had the main diagnose the anthropogenic changes of the relief at the basin of Corrego do Jardim São João, Araras (SP), comparing two scenes, 1997 and 2006, through geomorphological mapping evolutionary in the area. The geomorphological feature altered at the basin are directly linked to the use of soil, mainly at the urban use, which caused effects in the relief at the studied area, making possible to define periods of the urban evolution and impacts caused by the urbanization. Among the changes it was found the decrease of the topographic breaks and at the riverbed channels, as the increase of the accumulation of the plain and riverbed terrace. The elaboration of a letter of the legal restrictions of the basin make possible to evaluate some of the environmental urban problems that occur, which are due to the occupation of the relief in the areas of permanent preservation that brings significant impacts to...

Carta geológico-geotécnica aplicada ao planejamento urbano da região do Córrego Bertini, município de Americana - SP

This paper focuses on the implementation of a geological and geotechnical mapping to the planning of the region stream Bertini, territorial expansion area of the municipality of Americana (SP), a medium-sized city in the countryside of Sao Paulo state, with great potential for growth industrial and residential. To this end, based on the methodology established by the Institute for Technological Research, the charters geological and geotechnical aimed at exposing the capabilities and limitations of the soil. The analysis of similar soil characteristics such as geology, geomorphology, slope, geotechnical testing and the current use and land cover was possible to recognize four geotechinical units. The units I and III are related to areas of top and concave and convex parts of the study area, shown to be sites of low occupancy restriction. However the units II and IV, respectively allocated in the floodplain of the Piracicaba River and the banks of the stream Bertini and some of its drainage, showed a more restricted area due to proximity to water bodies and drainages that offer higher slopes.

Elaboração de mapa de susceptibilidade de corridas de massa/detritos e ondas de cheia, aplicado a empreendimentos dutoviários, na bacia hidrográfica do Ribeirão da Prata (SP)

Given the intense expansion of the industries in Brazil and the discovery of hydrocarbons in the pre-salt layer of the Santos and Campos Basin, there is a need to expand the distribution of oil and gas network in the country. The present work aims to present the development of susceptibility map by two distinct methods of two events (debris flows and full wave), applied to the establishment of pipelines on Ribeirão da Prata Basin. The research area covers two municipalities: São João da Boa Vista and Águas da Prata, in total 145 km2. In the paper was used the methodology proposed by Zaine (2011) for the physiographic subdivision method, which uses geological maps, geomorphological maps, digital terrain models and aerial photographs, used to extract the main elements of the physical environment, as rivers, lines, ridges, tops forms and valley forms and historical processes. Thus, the basin was divided into 11 physiographic zones, considering the following elements: thickness of soil, rock type, geomorphology, amplitude, ridges orientation, erosion occurences and mass movements. Were subsequently performed location maps of dams, that had as main purpose to localize major dams in the study area along with their area and perimeter of the reservoir, and land use map that subdivided the area in woody vegetation, permanent culture, temporary culture and urban area. Along with the preparation of the auxiliar maps was conducted a field campaign with three days and approximately 2 points per km2, which aimed to better understand the physical environment and check the main peculiarities of the study area. Criteria have been established for susceptibility maps physiographic subdivision and land use, and a survey of criteria weights used in each map for both processes under study. For the preparation of susceptibility maps were adopted two different methods, which treat the weighted average and the multiplicand. The weighted average method it is...