scholarly journals Imperfections in plaster surfaces caused by the release of hydrogen gas of polyvinylsiloxane impression materials

2013 ◽  
Vol 1 (2) ◽  
pp. 98
Author(s):  
Jefferson Ricardo Pereira ◽  
Janaina Salomon Ghizoni ◽  
Paulo Henrique Orlato Rossetti ◽  
Naudy Brodbeck May ◽  
Accácio Lins do Valle
Keyword(s):  
Stainless Steel ◽  
Statistical Analysis ◽  
Plaster Cast ◽  
Hydrogen Gas ◽  
Tukey Test ◽  
Type Iv ◽  
Impression Materials ◽  
Hydrogen Liberation ◽  
Stone Type ◽  
The Ideal

Purpose: The purpose of this study was to evaluate the number of bubbles of hydrogen liberation from different polyvinylsiloxane impression materials. Material and Methods: A metallic stainless steel jig containing six receptacles, like trays, was constructed to accommodate the impression materials. The molds were poured immediately, and at 1 hour, 12 hours and 24 hours in order to evaluate the number of bubbles present in each sample. Each sample was made of improved stone (type IV), totaling 48 samples for each polyvinylsiloxane impression material. After setting, the surface of each sample was inspected under a light microscope at 40x magnification and the number of bubbles was recorded. Results were submitted to statistical analysis by ANOVA and Tukey Test (p=.05). Results: ANOVA test showed statistically significant differences among the polyvinylsiloxane impression materials, as determined by the number of bubbles (p<.05). The Tukey test showed statistically significant differences among the three groups (p<.05). Conclusions: Statistical differences were found between addition silicone with regard to the ideal time to wait for the plaster cast, showing that Aquasil results in fewer bubbles in plaster, followed by the President and Simply Perfect samples.

scholarly journals Comparison of disinfection protocol of irreversible hydrocolloid (alginate) impressions through plastic and metallic trays

2014 ◽  
Vol 17 (3) ◽  
pp. 54 ◽  
Author(s):  
Luiz Kiyoaki Okazaki ◽  
Cidney Hiroaki Cato ◽  
Lúcia Teramoto ◽  
Anna Carolina Borges Pereira Costa ◽  
Marcelo Fava ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Sodium Hypochlorite ◽  
Cross Infection ◽  
Percentage Reduction ◽  
Effective Time ◽  
Colony Forming Unit ◽  
Tukey Test ◽  
Before And After ◽  
Irreversible Hydrocolloid ◽  
The Ideal

<p class="normal"><strong>Introduction</strong>: Many studies have evaluated the disinfection of irreversible hydrocolloid impressions through different disinfecting agents. However, impression trays can be source of cross-infection requiring disinfection. This study aimed to determine which would be the most suitable tray (metallic or plastic), available in dental market, and the ideal time to achieve disinfection by using 1% sodium hypochlorite poured into the alginate impression. <strong>Material and methods</strong>: Thirty dental impressions from the patients aged from 7-12 years and treated in the Discipline of Orthodontics of the institution were divided into two groups according to the impression tray type: 15 impressions through plastic tray (Morelli) and 15 impressions through metallic tray (Tecnodent). The material collection was performed before and after the application of 1% sodium hypochlorite for 3, 5 and 10 minutes. After the incubation period of 48 hours at 37ºC, the microorganism colonies were counted on the plates presenting from 30 to 300 colonies to determine the colony-forming unit (CFU) per mL. CFU/mL results were transformed into logarithm and submitted to statistical analysis by applying ANOVA and Tukey test (<em>p</em> ≤ 0.05). <strong>Results</strong>: Greater CFU percentage reduction occurred in alginate after three minutes, in both tray types. Concerning to tray types, it could be observed that the plastic tray showed 100% of reduction after 5 minutes while the metallic tray exhibited 81.49% of reduction after 3 minutes.<strong> Conclusion</strong>: 1 – The plastic tray showed the most effective disinfection after 5 minutes, with 100% of CFU reduction; 2 – The most effective time of disinfection with 1% sodium hypochlorite poured into the impression was 5 minutes, for both tray types.</p>

scholarly journals Influence of the implants inclination on the accuracy of the working cast

2010 ◽  
Vol 10 (2) ◽  
Author(s):  
Wirley G. Assunção ◽  
Juliana Aparecida Delben ◽  
Érica A. Gomes ◽  
Valentim A. R. Barão ◽  
Juliana R. P. Jorge
Keyword(s):  
Metallic Matrix ◽  
Conventional Technique ◽  
Control Group ◽  
Tukey Test ◽  
Type Iv ◽  
Significant Difference ◽  
Opposite Situation ◽  
Level Of Significance ◽  
Matrix Control ◽  
Stone Type

The aim of this study was to evaluate the influence of the implants inclination on the accuracy of the working cast obtained by two different pouring techniques. A metallic matrix containing two implants, positioned at 90 and 65 degrees in relation to the alveolar ridge, was submitted to the direct transfer impression technique. In CP group (conventional pouring - n=10), the impressions were poured with dental stone type IV using the conventional technique. In EP group (experimental pouring - n=10), the analogs were embraced with latex tubes before the first pouring. After sixty minutes, these tubes were removed and the space was filled with the dental stone. The metallic matrix (control group) and the replicas were evaluated regarding the implant/analog inclination and the vertical misfit between a framework and the implants/analogs. The data were tabulated and analyzed using analysis of variance (ANOVA) and Tukey test at the 0.05 level of significance. Regarding the analog inclination, both experimental groups differed statistically (p<0.05) from the control group only in relation to the leaning analogs. Results demonstrated significant difference (p<0.05) between the control group and the experimental groups when the reading of the vertical misfit was accomplished in the perpendicular implant/analog with the retention screw in the leaning implant/analog and between the control group and the EP group in the opposite situation. Considering the inclination, perpendicular implants produced more accurate casts independently of the plaster pouring technique.

scholarly journals Scarification with sulphuric acid of Schizolobium amazonicum Huber ex Ducke seeds - FABACEAE

2007 ◽  
Vol 64 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Eniel David Cruz ◽  
José Edmar Urano de Carvalho ◽  
Rafaela Josemara Barbosa Queiroz
Keyword(s):  
Statistical Analysis ◽  
Experimental Design ◽  
Seed Germination ◽  
Sulphuric Acid ◽  
Seed Coat ◽  
Immersion Time ◽  
Germination Index ◽  
Efficient Treatment ◽  
Tukey Test

Seed coat impermeability to water occurs in many species, including Schizolobium amazonicum Huber ex Ducke. To promote germination in seeds with coat impermeability the use of sulphuric acid (H2SO4) is recommended. The objective of this study was to identify a better time for the scarification with sulphuric acid for S. amazonicum seeds. The effect of scarification with sulphuric acid for 20, 40 and 60 min on germination and speed germination was studied for seeds that were either sowed immediately after scarification or after a 24-hour period of immersion in water. Seeds were sown on a mix of sand and sawdust (1:1). The experimental design was completely randomized with four replications of 50 seeds. The statistical analysis of germination was carried out at six, nine, 12, 15, 18, 21 and 24 days after sowing, in a factorial scheme. For speed germination the means were compared by the Tukey test. There was an interaction between treatments to overcome dormancy and immersion time after scarification in most evaluations. Immersion in water accelerated the beginning of germination. All treatments to overcome dormancy promoted seed germination. However, scarification for 60 min, showed better germination, 92% when immediately sown and 86.5% when sown after 24 hours. Speed germination index was highest for scarified seeds for 60 min followed by immersion in water. Scarification for 60 min was the most efficient treatment to promote germination in S. amazonicum seeds.

scholarly journals Statistical analysis of second order effects variation with the stories height of reinforced concrete buildings

2017 ◽  
Vol 10 (2) ◽  
pp. 333-357
Author(s):  
D.M. OLIVEIRA ◽  
N.A. SILVA ◽  
C.C. RIBEIRO ◽  
S.E.C. RIBEIRO
Keyword(s):  
Reinforced Concrete ◽  
Statistical Analysis ◽  
Second Order ◽  
Order Effects ◽  
Reinforced Concrete Buildings ◽  
First Order ◽  
Concrete Buildings ◽  
Ideal Situation ◽  
Second Order Effects ◽  
The Ideal

Abstract In this paper the simplified method to evaluate final efforts using γ z coefficient is studied considering the variation of the second order effects with the height of the buildings. With this purpose, several reinforced concrete buildings of medium height are analyzed in first and second order using ANSYS software. Initially, it was checked that the (z coefficient should be used as magnifier of first order moments to evaluate final second order moments. Therefore, the study is developed considering the relation (final second order moments/ first order moments), calculated for each story of the structures. This moments relation is called magnifier of first order moments, "γ", and, in the ideal situation, it must coincide with the γ z value. However, it is observed that the reason γ /γ z varies with the height of the buildings. Furthermore, using an statistical analysis, it was checked that γ /γ z relation is generally lower than 1.05 and varies significantly in accordance with the considered building and with the presence or not of symmetry in the structure.

scholarly journals EMERGÊNCIA E SOBREVIVÊNCIA DE PLANTAS DE SOJA A CAMPO EM RELAÇÃO ÀS PROFUNDIDADES E ÉPOCAS DE SEMEADURA

2020 ◽  
Vol 35 (2) ◽  
pp. 150-157
Author(s):  
Patrícia Pereira Dias ◽  
Saulo Fernando Gomes de Sousa ◽  
Paulo Roberto Arbex Silva ◽  
Tiago Pereira da Silva Correia ◽  
Anderson Ravanny de Andrade Gomes
Keyword(s):  
Glycine Max ◽  
Statistical Analysis ◽  
Field Experiment ◽  
Analysis Of Variance ◽  
Early Stage ◽  
Soybean Seed ◽  
Sowing Depth ◽  
Tukey Test ◽  
Glycine Max L ◽  
Soil Deposition

A PROFUNDIDADE DE SEMEADURA DA SOJA NA PLANTABILIDADE   PATRÍCIA PEREIRA DIAS1*, SAULO FERNANDO GOMES DE SOUSA2, PAULO ROBERTO ARBEX SILVA3, TIAGO PEREIRA DA SILVA CORREIA4 e ANDERSON RAVANNY DE ANDRADE GOMES5   * Parte do texto foi extraído da tese da autora 1 Departamento de Produção Vegetal, Universidade Estadual Paulista ‘Júlio de Mesquita Filho’ - Av. Universitária, 3780 - Altos do Paraíso, 18610-034, Botucatu - SP, Brasil. [email protected] 2 Agroefetiva, Rua Lourival Ferreira, 11 - Distrito Industrial III, 18608-853, Botucatu - SP, Brasil.  [email protected] 3 Departamento de Engenharia Rural e Socioeconomia, Universidade Estadual Paulista ‘Júlio de Mesquita Filho’ - Av. Universitária, 3780 - Altos do Paraíso, 18610-034, Botucatu - SP, Brasil.  [email protected] 4 Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, Caixa - Campos Universitário Darci Ribeiro ICC – Asa Norte, 04508, Brasília - DF, Brasil. [email protected] 5 Faculdade Regional da Bahia, Rodovia AL 220, 3630 - Senador Arnon De Melo - Planalto, Arapiraca – AL, Brasil. [email protected]   RESUMO: O objetivo deste trabalho foi avaliar a cultura da soja semeada a campo em diferentes profundidades das sementes e épocas de semeadura e, dessa maneira, saber o quanto esses fatores influenciam a emergência e sobrevivência das plantas. O experimento foi conduzido em dois anos agrícolas, 2015/16 e 2016/17, com sementes de soja cultivar 5D634, na Fazenda Lageado, da Faculdade de Ciências Agronômicas – UNESP, Botucatu (SP), Brasil. O delineamento foi de blocos ao acaso em esquema fatorial 6 × 2, com seis tratamentos referentes às profundidades das sementes na mesma linha de semeadura: 0,02, 0,05 e 0,08 m do nível do solo, e combinação e alternância entre eles: 0,02 e 0,05, 0,02 e 0,08, 0,05 e 0,08 m e duas épocas de semeadura: outubro e novembro, com quatro repetições, totalizando 48 parcelas. Para a análise estatística, os dados foram submetidos à análise de variância (ANOVA), utilizando o teste de Tukey a 5% de probabilidade. A perda foi acima de 10% no estande de plantas na semeadura mais profunda (0,08 m), aliada à menor precipitação (outubro/2016), que contribuiu significativamente para esse resultado. Desta forma, a plantabilidade é prejudicada com o erro da profundidade de semeadura, aqui representada pela emergência e sobrevivência de plantas.   Palavras-chave: Glycine max L., Plantabilidade, Estande de plantas.   THE SOYBEAN SOWING DEPTH IN PLANTABILITY   ABSTRACT: The aim of this work was evaluate the sowing of soybean seed with error in soil deposition and different month of sowing. The field experiment was carried out during two years (2015 and 2016) at Fazenda Lageado, Faculty of Agronomic Sciences - UNESP / Botucatu - SP, Brazil. The plots were randomized blocks in 6 × 2 factorial, six treatments referring to the depth of the seeds in soil: 0.02 (T1); 0.05 (T2 - control) and 0.08 (T3); 0.02 and 0.05 (T4); 0.02 and 0.08 (T5); 0.05 and 0.08 m (T6) and two sowing times: October and November. For statistical analysis the data were submitted to analysis of variance (ANOVA) using Tukey test at 5% probability. The number of plants in early stage decreased by over 10% in the deep seeding (0.08 m), added to the less rainfall (October / 2016) which contributed significantly to this result. Therefore, plantability is damaged by the error of sowing depth, represented here by the emergence and survival of plants.   Keywords: Glycine max L., Plantability, Early stage.

Effect of High Pressure Gaseous Hydrogen on Fatigue Properties of SUS304 and SUS316 Austenitic Stainless Steel

2018 ◽  
Author(s):  
Takashi Iijima ◽  
Hirotoshi Enoki ◽  
Junichiro Yamabe ◽  
Bai An
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Room Temperature ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Life Test ◽  
Air Atmosphere ◽  
Fatigue Life Test

A high pressure material testing system (max. pressure: 140 MPa, temperature range: −80 ∼ 90 °C) was developed to investigate the testing method of material compatibility for high pressure gaseous hydrogen. In this study, SSRT and fatigue life test of JIS SUS304 and SUS316 austenitic stainless steel were performed in high pressure gaseous hydrogen at room temperature, −45, and −80 °C. These testing results were compared with those in laboratory air atmosphere at the same test temperature range. The SSRT tests were performed at a strain rate of 5 × 10−5 s−1 in 105 MPa hydrogen gas, and nominal stress-strain curves were obtained. The 0.2% offset yield strength (Ys) did not show remarkable difference between in hydrogen gas and in laboratory air atmosphere for SUS304 and SUS316. Total elongation after fracture (El) in hydrogen gas at −45 and −80 °C were approximately 15 % for SUS304 and 20% for SUS316. In the case of fatigue life tests, a smooth surface round bar test specimen with a diameter of 7 mm was used at a frequency of 1, 0.1, and 0.01 Hz under stress rate of R = −1 (tension-compression) in 100 MPa hydrogen gas. It can be seen that the fatigue life test results of SUS304 and SUS316 showed same tendency. The fatigue limit at room temperature in 100 MPa hydrogen gas was comparable with that in laboratory air. The room temperature fatigue life in high pressure hydrogen gas appeared to be the more severe condition compared to the fatigue life at low temperature. The normalized stress amplitude (σa / Ts) at the fatigue limit was 0.37 to 0.39 for SUS304 and SUS316 austenitic stainless steels, respectively.

Compositional Effects in the Corrosion Of Type 347 and 316 Stainless Steel In Chemical Environments

CORROSION ◽  
1960 ◽  
Vol 16 (9) ◽  
pp. 433t-440t ◽  
Author(s):  
C. P. DILLON
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Statistical Analysis ◽  
Silicon Content ◽  
Chromium Content ◽  
General Corrosion ◽  
Low Carbon ◽  
Qualification Test ◽  
Annealed Material ◽  
Adequate Quality

Abstract Statistical analysis indicates that some improvement in corrosion resistance of Type 347 stainless steel, in so far as this is indicated by the Huey Test, can be effected by tightening control of the compositional limits. The major improvement is effected by limiting the maximum silicon content; the chromium content and the columbiurn: carbon ratio are next in importance. In practice, adequate quality control is probably established by the qualification test itself, since variables other than composition significantly affect the corrosion resistance of the alloy in boiling 65 percent nitric acid. Statistical analysis of both qualification tests and field corrosion tests of chromium-nickel-molybdenum stainless steel indicates that the influence of various compositional elements varies with environment. A compositional range that is best for one type of exposure is not the optimum composition for another. Performance of annealed material (or of sensitized extra low carbon material) in qualification tests cannot be used to indicate quality as to general corrosion resistance in other environments. In practice, the effect of variations of composition within the nominal ASME range do not significantly affect corrosion resistance. In isolated cases where performance is affected, this must be determined empirically. 6.2.5

Compatibility of type IV dental stones with polyvinyl siloxane impression materials

1987 ◽  
Vol 58 (1) ◽  
pp. 19-22 ◽  
Author(s):  
E. Schelb ◽  
C.V. Mazzocco ◽  
J.D. Jones ◽  
T. Prihoda
Keyword(s):  
Type Iv ◽  
Impression Materials

Hydrogen Assisted Fracture of Type 316 Stainless Steel at Sub-Ambient Temperature

2008 ◽  
Author(s):  
C. San Marchi ◽  
B. P. Somerday ◽  
X. Tang ◽  
G. H. Schiroky
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steels ◽  
Hydrogen Gas ◽  
Ambient Temperatures ◽  
316 Stainless Steel ◽  
Properties Of Materials ◽  
Effects Of Temperature ◽  
High Concentrations ◽  
Selection Of ◽  
Assisted Fracture

Applications requiring the containment and transport of hydrogen gas at pressures greater than 70 MPa are anticipated in the evolving hydrogen economy infrastructure. Since hydrogen is known to alter the mechanical properties of materials, data are needed to guide the selection of materials for structural components. Type 316 austenitic stainless steels are often considered one of the best choices for resistance to hydrogen-assisted fracture; however, at sub-ambient temperatures some alloy compositions of type 316 stainless steel can become more susceptible to hydrogen-assisted fracture than others. In this study, we report the tensile properties of two heats of type 316 stainless steel, emphasizing the effects of temperature and high concentrations of internal hydrogen on these properties.

Ductility and Fatigue Strength Loss of a Hydrogen-Charged 316L Austenitic Stainless Steel

2019 ◽  
Author(s):  
Un Bong Baek ◽  
Thanh Tuan Nguyen ◽  
Seung Hoon Nahm ◽  
Kwon Sang Ryu
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Strength Loss ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Fracture Elongation ◽  
Life Measurement ◽  
316L Austenitic Stainless Steel ◽  
Fatigue Life Test

Abstract The susceptibility of 316L-type austenite stainless steel to hydrogen was quantified by means of SSRT results and low-cycle fatigue life measurement. Both tests were conducted in the air condition after being charged with high-pressure hydrogen gas of 10 MPa and a temperature of 300°C for 120 hours. In addition, SSRT tests in gaseous hydrogen at a pressure of 10 MPa were also performed and compared to the tests conducted in hydrogen pre-charged and as-received conditions. The 0.2% yield strength and tensile strength did not show there to be a considerable difference between hydrogen pre-charging and the as-received conditions, whereas the gaseous hydrogen condition revealed a remarkable degradation in tensile properties, especially in terms of fracture elongation. In the case of fatigue life test, a considerable influence of hydrogen pre-charging in fatigue life properties was observed in the high strain amplitude regime whereas the measured values in the low strain deformation region are consistently comparable to that in the as-received condition. Fatigue limit was not affected by hydrogen pre-charging.

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