Experimental Design in the Optimization of a Microwave Acid Digestion Procedure of Biomorphic Ceramic Based on ZrO2

Abstract

The present work deals with the manufacturing of biomorphous ZrO₂-ceramics from oak wood as biological template structure. Oak wood was vacuum infiltrated with zirconia-sol. Subsequent pyrolysis in inert atmosphere at 800°C and annealing in air up to 1550°C resulted in the formation of porous, microcellular ZrO₂-ceramics. After the material characterization, we optimized the sample dissolution by acid attack in an oven under microwave irradiation. Experimental designs were used as a multivariate strategy for the effects evaluation of varying several variables. The optimization was performed using full factorial design 2⁴. Four variables (time, power, volume of HNO₃, and volume of HF) were considered as factors and as response the concentration of different metal ions in the optimization process.     

涂层辊筒技术——非织造布整理用涂层辊简装置的多功能工艺理念

单面低加料率的涂层辊筒装置应用在非织造布工业中有着悠久的历史,绝大多数用于非织造尿布顶层的低加料率,单面亲水或永久亲水.Andritz Ktisters(安德里兹寇司德)为进行高速生产的非织造布工业客户(速度高至1000m/min)提供量身定做的neXkiss涂层辊筒产品系列.最新开发的neXkiss plus拥有特殊的灵活性和最大的生产多功能性.     

4 Gbit/s GaAs MESFET laser-driver IC

A high-speed laser-driver IC has been fabricated using etched-gate enhancement/depletion-mode MESFET technology. It has been demonstrated that the device is capable of driving 25? load with 80 mA modulation current at up to 4 Gbit/s NRZ data rate.     

A software for optical characterization of thin films for microelectronic applications

We present a software for the optical characterization of thin films using spectrophotometric and/or ellipsometric measurements. The program allows the analysis of a wide range of multi-layered structures, either with respect to the composition, microstructure or thickness of any of the layers.     

Sterile Filtration of NanoCrystal™ Drug Formulations

A Nano Crystal^TM dispersion of the iodinated x-ray contrast agent iodipamide was prepared by wet milling the drug substance in the presence of Pluronic® F127 stabilizer. The mean particle size of the formulation was 98 nm and all drug particles in the formulation were smaller than 220 nm as determined by dynamic light scattering. Approximately 1 liter of dispersion was filtered through a sterile 0.2-μm disposable capsule filter (Supor® 200 DCF^TM, 0.I m² effective filtration area [EFA], Gelman Sciences) to condition the capsule. No drug concentration or size distribution changes were detected after the filtration process. The microbiological validation tests were performed using Pseudomonas diminuta organisms to challenge the capsule under simulated worst-case process conditions. The results showed that the Supor 200 DCF was able to retain 100% Pseudomonas diminuta organisms (≥10⁷ organisms per cm² of effective filtration area). Thus, this study demonstrated that terminal filtration is a feasible process to sterilize Nano Crystal^TM drug dispersions that may be chemically or physically unstable at elevated temperatures and thus not amenable to terminal heat sterilization.     

Graded-index-rod external coupled-cavity laser with backface output-monitor-stabilized single-frequency operation

We have demonstrated a graded-index-rod external coupled-cavity (GRECC) laser with backface output through a partially transmitting external cavity mirror. Laser output is monitored from the backface in a transmitter module with double-loop feedback control which stabilizes output power and maintains single-frequency operation under CW and pseudorandom pulse modulation.     

Preparation, Hardness, and Fracture Toughness of Tantalum Oxynitride Ceramics

Tantalum oxynitride powder with a baddeleyite crystal structure was synthesized and densified by hot pressing in Ar and under high pressure using a belt-type high-pressure apparatus. The tantalum oxynitride powder could not be densified completely under hot-pressing conditions at 1400°C. The use of high pressure resulted in dense materials. The samples showed a hardness of 16–17 GPa and a fracture toughness of 3–4 MPa·m^1/2. The hardness is higher compared with that of ZrO₂ and HfO₂ ceramics. The fracture toughness corresponds to the value of fully stabilized ZrO₂ due to the absence of any transformation toughening mechanism.     

The Role of the Individual – A Key to Learning in Preparedness Organizations

A well functioning societal response to crises is benefited by individuals having adequate skills and knowledge. From a municipal perspective this requires the creation of a learning organization. The objective of this study is to determine whether individual municipal employees, who have the responsibility for preparedness planning, reason and act in ways that promote learning about crises and preparedness issues throughout the municipal organization. Analysis of interviews with preparedness planners in six Swedish municipalities on their strategies for preparedness planning, reveal that preparedness planning too often becomes a demarcated activity, restricted to not more than a handful of individuals. This study indicates that one reason for why the preparedness work becomes demarcated is that individuals central to the preparedness planning are not taking on roles for acting in ways that are required in order for a learning organization to be established.     

Building phonotactic knowledge in bilinguals: Role of early exposure.

Timing and amount of exposure to a 2nd language in the acquisition of phonotactic restrictions was examined in 4 experiments. In Experiments 1 and 2, 10-month-old monolingual and bilingual Catalan-Spanish infants were presented with nonwords that were phonotactically legal or illegal in Catalan and phonotactically illegal in Spanish. Differences between the 4 groups of infants were obtained as a function of language dominance. In Experiments 3 and 4, adult Spanish-Catalan bilinguals were compared with the same materials. Catalan-dominant bilinguals were more accurate than Spanish-dominant bilinguals in their perception of legal sequences; however, they were not more accurate with illegal sequences. The findings suggest a complex correlation between the pattern of preference and the amount and timing of exposure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Secreted production of a custom-designed, highly hydrophilic gelatin in Pichia pastoris

A custom-designed, highly hydrophilic gelatin was produced in Pichia pastoris . Secreted production levels in single-copytransformants were in the range 3–6 g/l of clarified brothand purification to near homogeneity could be accomplished bydifferential ammonium sulfate precipitation. Despite the factthat gelatins are highly susceptible to proteolysis becauseof their unfolded structure, the recombinant protein was shownto be fully intact by SDS–PAGE, N-terminal sequencing,gel filtration chromatography and mass spectrometry. Owing toits highly hydrophilic nature, the migration of the syntheticgelatin in SDS–PAGE was severely delayed. Esterificationof the carboxylic amino acid side chains resulted in normalmigration. The high polarity of the synthetic gelatin also accountsfor its negligible surface activity in water at concentrationsup to 5% (w/v), as determined by tensiometry. Circular dichroismspectrometry showed that the non-hydroxylated gelatin did notform triple helices at 4°C. The spectrum was even more representativeof the random coil conformation than the spectrum of naturalnon-hydroxylated gelatins.