Effects of different polymerization protocols on the degree of conversion of two dual‐cured core buildup composites polymerized by light‐emitting diode and halogen light‐curing units

The aim of study was to investigate the effects of various curing protocols with quartz–tungsten halogen (QTH) or light‐emitting diode (LED) light‐curing units on the degree of conversion (% DC) of two dual‐cured core buildup resin composites. Two dual‐cured core buildup resin composites, Clearfil Dc Core Automix (CLF) and Grandio Core Dc (GR), were selected. Specimens were exposed to the polymerization protocols as follows: there was immediate photoactivation or photoactivation delayed by 2 or 5 min by a QTH or LED source, and one group was allowed to chemically polymerize and served as a control (n = 6). The % DC of the specimens was determined with attenuated total reflectance–Fourier transform infrared spectroscopy. The GR samples polymerized with QTH for the 5‐min‐delayed photoactivation had higher % DC values than those self‐cured, and the Clearfil Dc Core Automix (CLF) samples with immediate or delayed curing protocols with halogen yielded higher % DC values than the samples that were chemically polymerized. The comparison of the two resin composites polymerized with halogen showed a higher % DC for CLF than for GR in the 2‐min‐delayed photoactivation. On the other hand, when they were cured with LED, the % DC values of GR significantly increased after the 2‐min‐delayed photoactivation. In light of the results, it might be stated that CLF polymerized with QTH, could be the better option. GR provided adequate chemical polymerization; therefore, it might be useful in areas in which light curing is not possible. Clinicians should consider the polymerization characteristics of dual‐cured resin composites. The use of different composites may require the modification of the application procedures recommended by the manufacturer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40560.     

High‐resolution imaging of nanoparticle bimetallic catalysts supported on mesoporous silica

Although conventional high‐resolution transmission electron microscopy is a powerful method for the elucidation of the structure of mesoporous solids (diameter of pores from 1.5 to 20 nm), it is far less capable than high‐resolution scanning transmission electron microscopy in identifying the spatial distribution of nanocrystals of catalysts encapsulated within the mesopores. Using high‐angle annular dark‐field imaging (either in a 100 or 300 keV STEM system), it is possible to locate precisely individual bimetallic nanoparticles (Ag₃Ru₁₀, Cu₄Ru₁₂ and Pd₆Ru₆ hydrogenation catalysts) supported on mesoporous silica, to determine their size distribution, and to record their characteristic X‐ray emission maps. It is also established that there is little tendency for elemental fragmentation of the bimetallic catalysts, all of which were prepared by decarbonylating, by thermolysis, precursor cluster carbonylate anions: [Ag₃Ru₁₀C₂(CO)₂₈Cl]⁻, [Ru₆C(CO)₁₆Cu₂Cl]²⁻ and [Ru₆Pd₆(CO)₂₄]²⁻. This revised version was published online in July 2006 with corrections to the Cover Date.     

Microstructure and high-temperature tensile deformation of tiai(si) alloys made from elemental powders

Two ternary TiAl-based alloys with chemical compositions of Ti-46.4 at. pct Al-1.4 at. pct Si (Si poor) and Ti-45 at. pct Al-2.7 at. pct Si (Si rich), which were prepared by reaction powder processing, have been investigated. Both alloys consist of the intermetallic compounds y-TiAl, α₂-Ti₃Al, and ξ-Ti₅(Si, Al)₃. The microstructure can be described as a duplex structure(i.e., lamellar γ/α₂ regions distributed in γ matrix) containing ξ precipitates. The higher Si content leads to a larger amount of ξ precipitates and a finer y grain size in the Si-rich alloy. The tensile properties of both alloys depend on test temperature. At room temperature and 700 °C, the tensile properties of the Si-poor alloy are better than those of the Si-rich alloy. At 900 °C, the opposite is true. Examinations of tensile deformed specimens reveal ξ-Ti₅(Si, Al)₃ particle debonding and particle cracking at lower test temperatures. At 900 °C, nucleation of voids and microcracks along lamellar grain boundaries and evidence for recovery and dynamic recrystallization were observed. Due to these processes, the alloys can tolerate ξ-Ti₅(Si, Al)₃ particles at high temperature, where the positive effect of grain refinement on both strength and ductility can be utilized.     

Development and assessment of geothermal-based underground pumped hydroenergy storage system integrated with organic Rankine cycle and district heating

This study develops a geothermal-based underground pumped hydroenergy storage system (UPHES) integrated with an organic Rankine cycle (ORC) and district heating. The ORC has been integrated into the system for contributing the power demand of the pump used during the charging period to pump the water from the underground to the upper reservoir. District heating has been performed by geothermal. Heat recovered from the ORC has been used for the preheating of water used in district heating before entering the upper reservoir. With this proposed integrated system, both the peak energy demand has been shifted to off-peak hours and district heating has been performed. An ORC has also been included in the system to contribute to the energy demand of the UPHES pump. In order to evaluate the system's performance, thermodynamic analysis has been performed base on energetic and exergetic efficiencies. In the base case study, 60 MWh of electricity has stored by the UPHES. Also, a 2.8 MW of heating demand of 100 houses has been met and a 1.7 MW of power has been generated by the ORC. The power of the UPHES pump has been calculated as 6.81 MW. The efficiency of the UPHES system is 73.34%. Overall energy and exergy efficiencies of the proposed integrated system have been calculated as 93.09% and 78.37%, respectively.     

AMT 2.0: qualitative and quantitative trace analysis with extended signal temporal logic

International Journal on Software Tools for Technology Transfer - We introduce in this paper $$text {AMT} ; 2.0$$ , a tool for qualitative and quantitative analysis of hybrid continuous and...     

Effect of changing temperature on anaerobic hydrogen production and microbial community composition in an open-mixed culture bioreactor

The temperature effect (37–65 °C) on H₂ production from glucose in an open-mixed culture bioreactor using an enrichment culture from a hot spring was studied. The dynamics of microbial communities was investigated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). At 45 and 60 °C the H₂ production was the highest i.e. 1.71 and 0.85 mol H₂/mol glucose, respectively. No H₂ was produced at temperatures 50 and 55 °C. At 37–45 °C, H₂ production was produced by butyrate type fermentation while fermentation mechanism changed to ethanol type at 60 °C. Clostridium species were dominant at 37–45 °C while at 50–55 °C and 60 °C the culture was dominated by Bacillus coagulans and Thermoanaerobacterium, respectively. In the presence of B. Coagulans the metabolism was directed to lactate production. The results show that the mixed culture had two optima for H₂ production and that the microbial communities and metabolic patterns promptly changed according to changing temperatures.     

Characterization and thermoluminescence behavior of beta irradiated NaBaBO3 phosphor synthesized by combustion method

NaBaBO₃ host material was synthesized using the combustion method. In order to optimize the performance of the material, effects of sintering temperatures varying from 600° to 1000?°C were investigated. The sintering temperature and dwell time were found to have pronounced effects on the pure NaBaBO₃ material. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to confirm the phase formation and examine the surface morphology of the prepared powder material, respectively. TL behavior of NaBaBO₃ was studied at various beta doses. It is seen that the sample exhibits well resolved TL glow peak at a peak temperature about 175?°C and corresponding TL intensity increases with the increasing beta dose. However, TL glow peak slightly shifts to lower temperature with the increasing beta dose level. This is the first TL report of a phosphor with a NaBaBO₃ host. The TL kinetic parameters were estimated by the peak shape (PS) method and CGCD software. TL glow curves of NaBaBO₃ consist of several traps and exhibited second order kinetics. A possible TL mechanism was also discussed using the energy level model. The obtained results can provide valuable knowledge related to the investigation of the intrinsic nature characteristics of NaBaBO₃ in research fields pertaining to dosimetry.     

Developmental relations and patterns of change between alcohol use and number of sexual partners from adolescence through adulthood.

We explored two unanswered questions about the role of alcohol use in sexual behavior. First, we considered whether alcohol use temporally precedes and predicts changes in sexual behavior assessed as the number of sexual partners, whether the reverse pattern holds, or whether the association reflects a common, external cause. Second, we assessed whether associations between these behaviors change as adolescents transition to adulthood. These questions were addressed with a bivariate dual change latent difference score model. Drinking frequency and number of yearly sex partners were assessed 8 times across a 13-year period in a sample of 553 individuals. Assessment began when participants were in the 9th grade (age: M = 15.11 years, SD = 0.43). In addition to an association between the individual growth trajectories of these behaviors, alcohol use was a leading indicator of changes in number of sex partners throughout adolescence, but the reverse pattern was not supported. Of importance, the predictive association could not be explained by individual differences in impulsivity, excitement seeking, conduct problems, hostility/aggression, conventional attitudes, gender, or divorce. Finally, in a developmentally meaningful pattern, alcohol use ceased to significantly predict changes in the number of sexual partners as adolescents transitioned to adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)