Crystallization and characterization of Y2O3-SiO2 glasses

Glasses in the yttria-silica system with 20 to 40 mol pct Y2O3 were subjected to recrystallization studies after melting at 1900 to 2100 C in W crucibles in 1 and 50 atm N2. The TEM and XRD results obtained indicate the presence of the delta, gamma, gamma prime, and beta-Y2Si2O7 crystalline phases, depending on melting and quenching conditions. Heat treatment in air at 1100 to 1600 C increased the amount of crystallization, and led to the formation of Y2SiO5, cristabalite, and polymorphs of Y2Si2O7. Also investigated were the effects of 5 and 10 wt pct zirconia additions

CO and trans-cinnamaldehyde as corrosion inhibitors of I825, L80-13Cr and N80 alloys in concentrated HCl solutions at high pressure and temperature

Peer reviewedPostprin

Insights into the Mechanism of Intermediate-Depth Earthquakes from Source Properties as Imaged by Back Projection of Multiple Seismic Phases

This study investigates the spatial and temporal distribution of energy release of large, intermediate-depth earthquakes using a modified back projection technique first used to study the 2004 Sumatra-Andaman megathrust event. Multiple seismic phases are included in the back projection analysis, which provides the capability to determine the energy distribution with respect to depth and time. A total of 22 intermediate-depth earthquakes with moment magnitudes greater than or equal to 6.5 are investigated with hypocentral depths between 100 and 300 km. For most of these events, the vertical extent of energy release is either below the resolution of this study $(\leq5 km)$ or slightly above $(\leq15 km)$. This observation agrees with previous studies that find large, intermediate-depth earthquakes have subhorizontal rupture planes. The results also show a significant portion of the events have multiple rupture planes that are well separated in depth. The closeness in time of the ruptures on separate planes and the distance between the planes suggest dynamic triggering where the P waves from the first rupture initiate rupture on the second plane. We propose that a dehydration embrittlement mechanism combined with preferentially hydrated subhorizontal faults can explain the observations of dominant subhorizontal rupture planes and the frequent occurrence of rupture complexity involving multiple subevents.Earth and Planetary Science

Acoustic Liners for Turbine Engines

An improved acoustic liner for turbine engines is disclosed. The acoustic liner may include a straight cell section including a plurality of cells with straight chambers. The acoustic liner may also include a bent cell section including one or more cells that are bent to extend chamber length without increasing the overall height of the acoustic liner by the entire chamber length. In some cases, holes are placed between cell chambers in addition to bending the cells, or instead of bending the cells

An Examination of Pedagogy in Middle School Science and Its Effect on Student Achievement

The development of policies ensuring regular examination of American students has been one approach to the mandate of accountability within the United States. While the face of assessment in education and the subsequent policies continue to evolve, the method to which classrooms approach preparing students for these examinations does so as well, though not in concert. Although some research has attempted to connect the two, particularly in the fields of mathematics and reading, a clear link between pedagogy in science classrooms and student achievement on standardized exams has not yet been established. Using qualitative and quantitative data gathered through surveys and mining of historical public domains, the researcher has attempted to determine if an existing correlation between the predominant pedagogy of middle schools in a large, urban district in South Florida and achievement of students on the Florida Grade Eight Statewide Science Assessment can be substantiated. Significant differences were identified with regard to student achievement on this assessment and whole-class teacher demonstrations, students working in collaborative groups, and formative assessment use in the classroom, as well as with respect to the school-wide category of pedagogy and the school’s socioeconomic label. The impact of such information could be widespread, allowing for the reformation of pedagogy in science classrooms, professional development for current educators, and educator training provided at the collegiate level as well as policy maintenance and development

I Have to Teach How? Preparing Science Teachers for the Post-Pandemic Classroom

In this interactive presentation, participants will discuss the importance of incorporating methodologies for virtual, meaningful science instruction into the curriculum for pre-service science teachers. Participants will further engage in sharing of best practices for science instruction in the digital environment and examine pre-service student work and current teacher insights within this domain