Hydrothermal synthesis of perovskite and pyrochlore powders of potassium tantalate

Potassium tantalate powders were hydrothermally synthesized at 100 to 200 °C in 4 to 15 M aqueous KOH solutions. A defect pyrochlore, Kta_(2)O_(5)(OH). nH2O (n ≈ 1.4), was obtained at 4 M KOH, but at 7–12 M KOH, this pyrochlore was gradually replaced by a defect perovskite as the stable phase. At 15 M KOH, there was no intermediate pyrochlore, only a defect perovskite, K_(0.85)Ta_(0.92)O_(2.43)(OH)_(0.57) 0.15H_(2)O. Synthesis at higher KOH concentrations led to greater incorporation of protons in the perovskite structures. The potassium vacancies required for charge compensation of incorporated protons could accommodate water molecules in the perovskite structure

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells-update 2

An update of validation test results confirming the breakthrough in low earth orbit (LEO) cycle life of nickel-hydrogen cells containing 26 percent KOH electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel (IPV nickel-hydrogen cells has been previously reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40 000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. This test was conducted at Hughes Aircraft Company under a NASA Lewis contract. The purpose was to investigate the effect of KOH concentration on cycle life. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min discharge (2x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The boiler plate test results are in the process of being validated using flight hardware and real time LEO test at the Naval Weapons Support Center (NWSC), Crane, Indiana under a NASA Lewis Contract. Six 48 Ah Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells), and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The three 31 percent KOH cells failed (cycles 3729, 4165, and 11355). One of the 26 percent KOH cells failed at cycle 15314. The other two 26 percent KOH cells were cycled for over 16600 cycles during the continuing test

The Nature of Support from Adult Sansei (Third Generation) Children to Older Nisei (Second Generation) Parents in Japanese Canadian Families

Given the growing ethnocultural diversity of Canada's aging population and the increased research focus on the role of the family in the social support of older persons, it is important to explore the ways in which adult ethnic minority children provide assistance to older parents within the context of the family. The current study contributes to research on intergenerational support systems in later life in Japanese Canadian families by examining the factors, particularly the cultural value of oya koh koh (filial obligation), affecting the nature of support from adult children to older parents. Using data gathered from interviews with 100 older nisei (second generation) parents and 100 adult sansei (third generation) children in British Columbia, the study focuses on the frequency, quality and provision of three types of support: emotional, service, and financial. Results of logistic regression analyses indicate that oya koh koh has a significant effect on children's provision of emotional support, but no effect on financial or service support. Parent's health and socioeconomic status are found to have significant effects on children's provision of financial and service support. Child's availability is also a major determinant of financial support. Further, ordinary least squares (OLS) regression analyses results suggest that oya koh koh has a significant effect on the quality of emotional support provided by children to their parents. Findings are discussed in terms of the North American Asian "ideal" family myth and directions for future research.family support; filial obligation, intergenerational relations; Japanese Canadian; model minority myth

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight battery cells

A breakthrough in low earth orbit (LEO) cycle life of individual pressure vessel (IPV) nickel hydrogen battery cells was reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. The effect of KOH concentration on cycle life was studied. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min charge (2 x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The next step is to validate these results using flight hardware and a real time LEO test. NASA Lewis has a contract with the Naval Weapons Support Center (NWSC), Crane, Indiana, to validate the boiler plate test results. Six 48 A-hr Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells) and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The cells were cycled for over 8000 cycles in the continuing test. There were no failures for the cells containing 26 percent KOH. There was two failures, however, for the cells containing 31 percent KOH

Destructive physical analysis results of Ni/H2 cells cycled in LEO regime

Six 48-Ah individual pressure vessel (IPV) Ni/H2 cells containing 26 and 31 percent KOH electrolyte were life cycle tested in low Earth orbit. All three cells containing 31 percent KOH failed (3729, 4165, and 11,355 cycles), while those with 26 percent KOH were cycled over 14,000 times in the continuing test. Destructive physical analysis (DPA) of the failed cells included visual inspections, measurements of electrode thickness, scanning electron microscopy, chemical analysis, and measurements of nickel electrode capacity in an electrolyte flooded cell. The cycling failure was due to a decrease of nickel electrode capacity. As possible causes of the capacity decrease, researchers observed electrode expansion, rupture, and corrosion of the nickel electrode substrate, active material redistribution, and accumulation of electrochemically undischargeable active material with cycling

Multi-silicon ridge nanofabrication by repeated edge lithography

We present a multi-Si nanoridge fabrication scheme and its application in nanoimprint\ud lithography (NIL). Triple Si nanoridges approximately 120 nm high and 40 nm wide separated\ud by 40 nm spacing are fabricated and successfully applied as a stamp in nanoimprint lithography.\ud The fabrication scheme, using a full-wet etching procedure in combination with repeated edge\ud lithography, consists of hot H3PO4 acid SiNx retraction etching, 20% KOH Si etching, 50% HF\ud SiNx retraction etching and LOCal Oxidation of Silicon (LOCOS). Si nanoridges with smooth\ud vertical sidewalls are fabricated by using Si 110 substrates and KOH etching. The presented\ud technology utilizes a conventional photolithography technique, and the fabrication of multi-Si\ud nanoridges on a full wafer scale has been demonstrated

Preparation and characterization of activated carbon from palm kernel shell

In Malaysia, the production of activated carbons is still coconut-based although Malaysia has long shifted from coconut into palm oil plantation. Huge amount of waste Palm Kernel Shells (PKS) are being generated and disposed off into the landfill with little known of their usage on large scale. In this study, the potential of production of activated carbon from raw palm kernel shells are studied. Activated carbon was prepared from raw palm kernel shells using chemical activation with potassium hydroxide (KOH) as an activating agent. The effects of different process parameters: KOH concentration, activation temperature and time on physicochemical properties of the prepared activated carbon were investigated. The activated carbon was analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier Transform Infrared (FTIR) spectroscopy, proximate analysis and methylene blue adsorption study. FTIR analysis indicates that raw palm kernel shell has successfully been converted into activated carbon. SEM photograph revealed that prepared activated carbons have numerous burn-off pores with extensive surface area for adsorption. Activated carbon sample prepared at 700 ºC and 1 hour activation with 30 wt % KOH impregnation showed greatest extend of methylene blue removal of 6.932 mg/g equivalent to 69.324 %RE with largest specific surface area of 21.137 x 10-3 km2kg-1 have been reported. This study shows that palm kernel shells can be used as a good source for the production of activated carbon

On the parametric representation of univalent functions on the polydisc

We consider support points of the class $S^0(\mathbb{D}^n)$ of normalized univalent mappings on the polydisc $\mathbb{D}^n$ with parametric representation and we prove sharp estimates for coefficients of degree 2.Comment: Minor corrections, references added. Thanks to Iason Efraimidis and Gabriela Koh

Film breakers prevent migration of aqueous potassium hydroxide in fuel cells

Electrolyte film breakers made from polytetrafluoroethylene are installed in the reactant and water vapor removal outlets of each cell and sealed by elastomers. Use of these devices in the water vapor removal cavity outlets prevents loss of KOH solution through film migration during water removal