The Ohara glass S-FTM16 is of considerable interest for near-infrared optical designs because it transmits well through the K band and because negative S-FTM16 elements can be used to accurately achromatize positive calcium fluoride elements in refractive collimators and cameras. Glass manufacturers have sophisticated equipment to measure the refractive index at room temperature, but cannot typ...

A dilatometer cell that can detect sub angstrom changes in the length of solid specimens in the temperature range 5 K<T<350 K is described. It is constructed entirely from fused quartz (silica). This is a capacitive-based technique, where the spacing between two metallized plates allows detection of changes in length. It is also a relative measurement in the sense that the capacitor plate spaci...

A cobalt-based thermoelectric compound Ca(3)Co(2)O(6) (CCO) has been developed as new cathode material with superior performance for intermediate-temperature (IT) solid-oxide fuel cell (SOFC). Systematic evaluation has been carried out. Measurement of thermal expansion coefficient (TEC), thermal-stress (σ) and interfacial shearing stress (τ) with the electrolyte show that CCO matches well with ...

Sensors, IR beams and lasers used in many opto-mechanical systems have stringent alignment retention requirements for use over an extended temperature range. Thermal effects are the primary cause for alignment drift during operation. Thermal expansion and contraction of materials can result in dimensional instability of mirror surfaces. This paper focuses on the importance of dimensional stabil...

In this work, a ceramic composite of ZrW2O8 and ZrO2 was synthesized, in order to investigate the possibility of compensating the positive thermal expansion of ZrO2 with the negative thermal expansion (NTE) compound ZrW2O8, tailoring the thermal expansion of these composites. The NTE material was mixed with varying amounts of ZrO2. The thermal expansion coefficients of this series of composites...

The present study of Ni2MnGe is focused on describing the thermal properties of the alloy in the framework of first-principles electronic structure calculations coupled with a Debye treatment of the vibrating lattice. The electronic structure of Ni2MnGe has been studied using the full-potential nonorthogonal local-orbital minimum basis method. Two approximations for Grüneisen parameter γ, i.e. ...

Solid solutions with the composition Ba0.5Sr0.5Zn₂Si2-xGexO₇ and BaZn₂Si2-xGexO₇ were prepared with different values of x using a conventional mixed oxide route. Both compounds exhibit very different thermal expansion, which is due to the different crystal structures. Ba0.5Sr0.5Zn₂Si2-xGexO₇ solid solutions exhibit the structure of high-temperature BaZn₂Si₂O₇ and show negative thermal expansion...

Atmospheric leakage between a CELSS and its surround is driven by the differential pressure between the two. In an earth-based CELSS, both negative and positive differential pressures of atmosphere are created as the resultant of three influences: thermal expansion/contraction, transition of water between liquid and vapor phases, and external barometric pressure variations. The resultant may ty...

In the present study, the effect of the chemical and phase composition on the thermal properties of silicon oxide carbides (SiOC) has been investigated. Dense monolithic SiOC materials with various carbon contents were prepared and characterized with respect to their thermal expansion, as well as thermal conductivity. SiOC glass has been shown to exhibit low thermal expansion (e.g., ca. 3.2 × 1...