The influence of B4C and MgB2 additions on the behavior of MgO-C bricks

Carbon-containing refractory materials have received great attention over the last years due to their importance in the steelmaking process. The oxidation of carbon present in refractory materials at temperatures above 500 degrees C is usually accompanied by the decrease of their mechanical strength and chemical resistance. Aiming to improve the oxidation resistance of carbon-oxide refractories, the use of materials known as antioxidants has been extensively studied. In this work we evaluated the performance of MgB2 and B4C antioxidants when incorporated into MgO-C bricks. We observed that the co-addition of metallic antioxidants and B4C or MgB2 leads to refractory bricks with enhanced hot modulus of rupture and resistance against oxidation and slag corrosion. However, the excessive addition of these antioxidants could impair the performance of the obtained bricks. Thus, when determining the optimum concentration of MgB2 and B4C to be added into MgO-C refractories, one must take into consideration this behavior. (c) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Confronto fra periodizzazione Tradizionale e a Blocchi per l’allenamento della forza in atleti maschi e partecipanti di genere femminile.

La prima parte dello studio riguarda la descrizione dell’origine e delle caratteristiche che differenziano la periodizzazione tradizionale e quella a blocchi per l’allenamento della forza. L’obiettivo della seconda parte del lavoro è stato quello di confrontare gli adattamento ormonali e prestativi ad un programma di allenamento della forza periodizzato secondo il modello tradizionale o secondo quello a blocchi in un campione di atleti di forza. Venticinque atleti maschi sono stati assegnati con procedura randomizzata al gruppo con programmazione tradizionale (TP) o a quello a blocchi (BP). Prelievi di saliva sono stati effettuati prima e dopo 6 diverse sedute di allenamento durante il programma al fine di rilevare i livelli di testosterone (T) e cortisolo (C). Le valutazioni dei parametri antropometrici e prestativi sono state effettuate prima e dopo le 15 settimane di allenamento previste. In nessuno dei due gruppi vi sono state variazioni significative nei livelli ormonali. I risultati indicano che il gruppo BP ha ottenuto incrementi superiori a quello TP riguardo alla forza massima (p = 0,040) ed alla potenza (p = 0,035) espressa alla panca piana. Nella terza parte dello studio, la periodizzazione tradizionale e quella a blocchi sono state confrontate riguardo agli effetti sulla forza massima e sull’ipertrofia in donne allenate di livello amatoriale. Diciassette donne hanno partecipato all’esperimento allenandosi 3 volte a settimana per 10 settimane. I risultati dimostrano che entrambe le periodizzazioni hanno portato a miglioramenti significativi di forza e potenza; il gruppo TP ha tuttavia ottenuto incrementi superiori di forza massima (p = 0,039) e ipertrofia degli arti inferiori (p = 0,004). La periodizzazione tradizionale quindi si è dimostrata più efficace per aumentare la forza massima e la sezione muscolare della coscia in partecipanti di genere femminile. I risultati contrastanti nei due generi potrebbero essere legati a rapporti diversi fra processi anabolici e catabolici.

Performance Factors in Women's Team Handball: Physical and Physiological Aspects—A Review

Team handball is an Olympic sport played professionally in many European countries. Nevertheless, a scientific knowledge regarding women's elite team handball demands is limited. Thus, the purpose of this article was to review a series of studies (n = 33) on physical characteristics, physiological attributes, physical attributes, throwing velocity, and on-court performances of women's team handball players. Such empirical and practical information is essential to design and implement successful short-term and long-term training programs for women's team handball players. Our review revealed that (a) players that have a higher skill level are taller and have a higher fat-free mass; (b) players who are more aerobically resistant are at an advantage in international level women team handball; (c) strength and power exercises should be emphasized in conditioning programs, because they are associated with both sprint performance and throwing velocity; (d) speed drills should also be implemented in conditioning programs but after a decrease in physical training volume; (e) a time-motion analysis is an effective method of quantifying the demands of team handball and provides a conceptual framework for the specific physical preparation of players. According to our results, there are only few studies on on-court performance and time-motion analysis for women's team handball players, especially concerning acceleration profiles. More studies are needed to examine the effectiveness of different training programs of women's team handball players' physiological and physical attributes.

Effect of the C-factor and Dentin Preparation Method in the Bond Strength of a Mild Self-etch Adhesive

This study evaluated the effect of the C-factor and dentin preparation method (DPM) in the bond strength (BS) of a mild self-etch adhesive; the study also observed the SEM superficial aspects of the corresponding smear layer. For purposes of this study, 25 molars (n=5) were used in a bond strength test. The molars were divided into two parts (buccal and lingual): one part received a Class V cavity (C-factor=3) and the other received a flat surface (C-factor=0) with the same bur type (coarse diamond or carbide bur and fine diamond or carbide bur), both within the same dentin depth. Five teeth were prepared with wet 60-grit and 600-grit SiC papers. After restoration with Clearfil SE Bond, microtensile beans (0.8 mm(2)) were prepared and tested after 24 hours in a universal testing machine (0.5 mm/minute). An additional two teeth for each DPM were prepared for SEM evaluation of the smear layer superficial aspects. The BS values were submitted to one-way ANOVA, considering only the DPM (flat surfaces) and two-way ANOVA (C-Factor x DPM, considering only burs) with p=0.05. Although the DPM in the flat surfaces was not significant, the standard deviations of carbide bur-prepared specimens were markedly lower. The BS was significantly lower in cavities. The fine carbide bur presented the most favorable smear layer aspect. It was concluded that different dentin preparation methods could not prevent the adverse effect in bond strength of a high C-factor. A coarse cut carbide bur should be avoided prior to a mild self-etch adhesive, because it adversely affected bond strength. In contrast, a fine cut carbide bur provided the best combination: high bond strength with low variability, which suggests a more reliable bond strength performance.

Does ear C sink strength contributes to the overcoming of photosynthetic acclimation of wheat plants exposed to elevated CO2?

Wheat plants (Triticum durum Desf., cv. Regallo) were grown in the field to study the effects of contrasting [CO2] conditions (700 versus 370 μmol mol−1) on growth, photosynthetic performance, and C management during the post-anthesis period. The aim was to test whether a restricted capacity of sink organs to utilize photosynthates drives a loss of photosynthetic capacity in elevated CO2. The ambient 13C/12C isotopic composition (δ13C) of air CO2 was changed from-10.2 in ambient [CO2] to-23.6 under elevated [CO2] between the 7th and the 14th days after anthesis in order to study C assimilation and partitioning between leaves and ears. Elevated [CO2] had no significant effect on biomass production and grain filling, and caused an accumulation of C compounds in leaves. This was accompanied by up-regulation of phosphoglycerate mutase and ATP synthase protein content, together with down-regulation of adenosine diphosphate glucose pyrophosphatase protein. Growth in elevated [CO2] negatively affected Rubisco and Rubisco activase protein content and induced photosynthetic down-regulation. CO2 enrichment caused a specific decrease in Rubisco content, together with decreases in the amino acid and total N content of leaves. The C labelling revealed that in flag leaves, part of the C fixed during grain filling was stored as starch and structural C compounds whereas the rest of the labelled C (mainly in the form of soluble sugars) was completely respired 48 h after the end of labelling. Although labelled C was not detected in the δ13C of ear total organic matter and respired CO2, soluble sugar δ13C revealed that a small amount of labelled C reached the ear. The 12CO2 labelling suggests that during the beginning of post-anthesis the ear did not contribute towards overcoming flag leaf carbohydrate accumulation, and this had a consequent effect on protein expression and photosynthetic acclimation.

Effects of 174 G/C polymorphism in the promoter region of the interleukin-6 gene on plasma IL-6 levels and muscle strength in elderly women

We investigated the effect of -174 G/C single-nucleotide polymorphism in the promoter region of the IL6 gene on plasma IL-6 levels and muscle strength, and the relationship between IL-6 levels and muscle strength in elderly women. The sample consisted of 199 elderly residents (73.0 ± 7.8 years old) from rest homes and the community in Belo Horizonte, MG, Brazil. -174 G/C polymorphism was determined by direct sequencing of the product by PCR, and plasma IL-6 concentrations were measured by ELISA. Muscle strength in the knee joint was evaluated using a Biodex System 3 Pro® isokinetic dynamometer. ANCOVA was used to determine the effect of polymorphism on IL-6 levels and muscle strength, and the Pearson correlation coefficient to assess the relationship between IL-6 levels and muscle strength. -174 G/C polymorphism was associated with the plasma IL-6 levels of elderly women (P < 0.01) since homozygotes for the G allele showed high IL-6 levels (GG 3.85 pg/mL, GC + CC 2.13 pg/mL). There was no association of polymorphism on muscle strength (P > 0.05). No association was found between IL-6 levels and knee extensor muscle (r = 0.087, P = 0.306) or flexor (r = -0.011, P = 0.894) strength. An interaction between -174 G/C polymorphism and housing conditions of the sample of elderly women was identified, with the effect of genotype on IL-6 levels being higher in the institutionalized elderly. These results support the evidence that -174 G/C polymorphism of the IL6 gene associates with individual variability of plasma IL-6 levels in elderly women.

Fatigue strength of HVOF sprayed Cr(3)C(2)-25NiCr and WC-10Ni on AISI 4340 steel

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

Recent & important national discoveries; of a system for preparing substitutes for hay, without risk of getting; and in causing corn, straw, turnips, &c. to be of double strength, for the more rapid feeding of horses, beasts, sheep, &c.

Mode of access: Internet.

A narrative of an attempt made by the French of Canada upon the Mohaques country microform : being Indians under the protection of Their Majesties government of New York : to which is added, 1. An account of the present state, and strength of Canada, given by two Dutch-men, who have been prisoners there, and now made their escape, 2. The examination of a French prisoner, 3. His Excellency Benjamin Fletcher's speech to the Indians, 4. The answer of the five nations of the Mohaques to His Excellency, 5. Proposals made by the four chief sachims of the five nations, to His Excellency, and His Excellency's reply thereto, 6. An address from the corporation of Albany to His Excellency, returning thanks for His Excellency's early assistance for their relief, &c. /

Imprint from colophon.

The world as it is, containing a view of the present condition of its principal nations as to their forms of government, military and naval strength, revenues, banking institutions, prison discipline, commerce, religion, morals, education, &c., &c., with anecdotes of distinguished characters.

Mode of access: Internet.

Effect Of Simulated Microwave Disinfection On The Linear Dimensional Change, Hardness And Impact Strength Of Acrylic Resins Processed By Different Polymerizing Cycles.

This study investigated the effect of simulated microwave disinfection (SMD) on the linear dimensional changes, hardness and impact strength of acrylic resins under different polymerization cycles. Metal dies with referential points were embedded in flasks with dental stone. Samples of Classico and Vipi acrylic resins were made following the manufacturers' recommendations. The assessed polymerization cycles were: A-- water bath at 74ºC for 9 h; B-- water bath at 74ºC for 8 h and temperature increased to 100ºC for 1 h; C-- water bath at 74ºC for 2 h and temperature increased to 100ºC for 1 h;; and D-- water bath at 120ºC and pressure of 60 pounds. Linear dimensional distances in length and width were measured after SMD and water storage at 37ºC for 7 and 30 days using an optical microscope. SMD was carried out with the samples immersed in 150 mL of water in an oven (650 W for 3 min). A load of 25 gf for 10 sec was used in the hardness test. Charpy impact test was performed with 40 kpcm. Data were submitted to ANOVA and Tukey's test (5%). The Classico resin was dimensionally steady in length in the A and D cycles for all periods, while the Vipi resin was steady in the A, B and C cycles for all periods. The Classico resin was dimensionally steady in width in the C and D cycles for all periods, and the Vipi resin was steady in all cycles and periods. The hardness values for Classico resin were steady in all cycles and periods, while the Vipi resin was steady only in the C cycle for all periods. Impact strength values for Classico resin were steady in the A, C and D cycles for all periods, while Vipi resin was steady in all cycles and periods. SMD promoted different effects on the linear dimensional changes, hardness and impact strength of acrylic resins submitted to different polymerization cycles when after SMD and water storage were considered.

Effect Of Simulated Microwave Disinfection On The Linear Dimensional Change, Hardness And Impact Strength Of Acrylic Resins Processed By Different Polymerization Cycles.

This study investigated the effect of simulated microwave disinfection (SMD) on the linear dimensional changes, hardness and impact strength of acrylic resins under different polymerization cycles. Metal dies with referential points were embedded in flasks with dental stone. Samples of Classico and Vipi acrylic resins were made following the manufacturers' recommendations. The assessed polymerization cycles were: A) water bath at 74 ºC for 9 h; B) water bath at 74 ºC for 8 h and temperature increased to 100 ºC for 1 h; C) water bath at 74 ºC for 2 h and temperature increased to 100 ºC for 1 h; and D) water bath at 120 ºC and pressure of 60 pounds. Linear dimensional distances in length and width were measured after SMD and water storage at 37 ºC for 7 and 30 days using an optical microscope. SMD was carried out with the samples immersed in 150 mL of water in an oven (650 W for 3 min). A load of 25 gf for 10 s was used in the hardness test. Charpy impact test was performed with 40 kpcm. Data were submitted to ANOVA and Tukey's test (5%). The Classico resin was dimensionally steady in length in the A and D cycles for all periods, while the Vipi resin was steady in the A, B and C cycles for all periods. The Classico resin was dimensionally steady in width in the C and D cycles for all periods, and the Vipi resin was steady in all cycles and periods. The hardness values for Classico resin were steady in all cycles and periods, while the Vipi resin was steady only in the C cycle for all periods. Impact strength values for Classico resin were steady in the A, C and D cycles for all periods, while Vipi resin was steady in all cycles and periods. SMD promoted different effects on the linear dimensional changes, hardness and impact strength of acrylic resins submitted to different polymerization cycles when after SMD and water storage were considered.

Effect Of Composite Containing An Iodonium Salt On The Bond Strength Of Brackets To Bovine Enamel.

This study investigated the effect of the incorporation of an iodonium salt in experimental composites, on the bond strength of metallic brackets bonded to bovine teeth. Two hundred and seventy bovine teeth were embedded in self-curing acrylic resin and divided into 18 groups (n=15), according to the experimental composite with an iodonium salt at molar concentrations 0 (control), 0.5, or 1%; the light-activation times (8, 20 and 40 s); and the storage times (10 min or 24 h). Metallic brackets were fixed on the tooth surface using experimental composites. Photoactivation was performed with a quartz-tungsten-halogen light-curing unit curing unit for 8, 20 and 40 s. The specimens were stored in distilled water at 37 °C for 10 min or 24 h and submitted to bond strength test at 0.5 mm/min. The data were subjected to three-way ANOVA and Tukey's test (α=0.05). The Adhesive Remnant Index (ARI) was used to classify the failure modes. The shear bond strengths (MPa) at 10 min for light-activation times of 8, 20 and 40 s were: G1 - 4.6, 6.9 and 7.1; G2 - 8.1, 9.2 and 9.9; G3 - 9.1, 10.4 and 10.7; and at 24 h were: G1 - 10.9, 11.1 and 11.7; G2 - 11.8, 12.7 and 14.2; G3 - 12.1, 14.4 and 15.8. There was a predominance of ARI score 3 for groups with 10 min storage time, and ARI score 2 for groups with 24 h storage time. In conclusion, the addition of iodonium salt (C05 and C1) to the experimental composite may increase the bond strength of brackets to bovine enamel using reduced light exposure times.

Dentin Bond Strength Of A Fluoride-releasing Adhesive System Submitted To Ph-cycling.

To evaluate the microtensile bond strength (µTBS) of a fluoride-containing adhesive system submitted to a pH-cycling and storage time regimen for primary outcomes. As secondary outcomes the fluoride released amount was evaluated. Twelve dentin surfaces from sound third molar were divided into 2 groups according to adhesive systems: Clearfil SE Protect (PB) and Clearfil SE Bond (SE). Sticks obtained (1.0 mm2) from teeth were randomly divided into 3 subgroups according to storage regimen model: immediate (24h); 5-month deionized water (W); and pH-cycling model (C). All sticks were tested for µTBS in a universal testing machine. Fluoride concentration was obtained from 1-4 days and 30-day in W and 1-4 days in demineralization (DE)/remineralization (RE) solutions from C, using a fluoride-specific electrode. µTBS and fluoride released data were, respectively, submitted to ANOVA in a split plot design and Tukey, and Friedman' tests (a=0.05). There was no significant interaction between adhesive system and storage regimen for µTBS. W showed the lowest µTBS values. There was no significant difference between 24 h and C models for µTBS. There was no significant difference between adhesive systems. Failure mode was predominantly cohesive within composite for the 24 h and W, for the C group it was mixed for SE and cohesive within composite for PB adhesive system. Fluoride concentrations in the DE/RE solutions were less than 0.03125 ppm and not detected in W. In conclusion, the fluoride-containing adhesive system performed similarly to the regular one. Hydrolytic degradation is the main problem with both adhesive systems, regardless of fluoride contents.