Rapid Process for Manufacturing Aluminum Nitride Powder

A rapid, direct nitridation process for the manufacture of sinterable aluminum nitride (A1N) powder was developed at the pilot scale. Atomized aluminum metal and nitrogen gas were heated and reacted rapidly to synthesize A1N while they passed through the reaction zone of a transport flow reactor. The heated walls of the reactor simultaneously initiated the reaction and removed the generated heat to control the exotherm. Several variations of the process were required to achieve high conversion and reduce wall deposition of the product. The fine A1N powder produced did not require a postreaction grinding step to reduce particle size. However, a secondary heat treatment, following a mild milling step to expose fresh surface, was necessary to ensure complete conversion of the aluminum. In some instances, a final air classification step to remove large particles was necessary to promote densification by pressureless sintering. The A1N powder produced was pressureless sintered with 3 wt% yttria to fabricate fully dense parts which exhibited high thermal conductivity. The powder was shown to be less sinterable than commercially available car-bothermally produced powders.     

Synthesis, Densification, and Conductivity Characteristics of BICUVOX Oxygen-Ion-Conducting Ceramics

Copper-substituted bismuth vanadate (Bi₂V_0.9Cu_0.1O_5.35), known as BICUVOX, possesses high oxygen ion conductivities at low temperatures. The ionic conductivity of this material at 300°C (∼1 × 10⁻³ S/cm) is 50 to 100 times greater than any other solid electrolyte in this temperature range. In this paper we report the preparation of sinterable BICUVOX powders by solid-state reaction and conventional ceramic powder processing techniques. Densification studies indicate that optimum densities (>95% theoretical) can be obtained after 10-20 h sintering at 800°C. Ionic conductivity characteristics were evaluated with respect to temperature, sample density, and prolonged isothermal heating.     

Retention of linoleic acid in carcass lipids of rats fed different levels of essential fatty acids

Rats of an inbred Sprague-Dawley strain were fed purified diets with low (0.3% of total energy), normal (3%) or high (10%) content of essential fatty acids (EFA) for at least three generations. Two 30-days-old rats with similar weights were chosen from one litter. One was killed; weight increase and food consumption of the other rat was measured for 15 days. Total lipid content and fatty acid composition in total lipid and lipid classes were determined in both rats. Seven pairs of rats from each group were treated in the same way. Calculations based an amount of linoleic acid ingested and retained in the carcass lipids showed that 50% of the ingested linoleic acid was retained in the low EFA rats compared to 10–15% in the normal and high EFA rats.     

Scanning photoluminescence technique to determine the phase of thegrating at the facets of gain-coupled DFB's

We demonstrate a rapid, nondestructive scanning photoluminescence (PL) technique for the determination of the phase of the grating at the cleaved or coated facets of “in-phase” gain-coupled distributed feedback lasers. The measured phases of the grating at the cleaved facets of a bar of lasers are found to be consistent with experimental measurements of laser performance     

Examination of Components of Variance for A Production Scale, Low Dose Powder Blend and Resulting Tablets

A study was performed to quantify the contributions of the different components comprising the total variance term observed following the analysis of content uniformity testing of powder blends and tablets. A full scale (400 kg) blend study was performed on a low dose tablet formulation (drug content = 0.13%). Content uniformity samples were pulled from throughout the blender using a pocket type probe thief in a manner which allowed the blend to be assessed for both homogeneity and sample to sample variability at a given location. Tablets were compressed from the batch and assayed for content uniformity. Sampling error accounted for approximately 75% of the variance observed following analysis of drug content in the powder blends. The estimated total variance for the powder blend was approximately twice that observed for tablets compressed from the mixture. The analytical contribution to the total variance term was minor. The difference between the estimated total variance terms for powder blend and tablets was attributed to the superior sampling efficiency of the tablet press versus the sample thief. The results of the study support the use of wider specifications for powder blends than the tablets compressed from the mixture.     

Predicting sensory profiles from external instrumental measurements

Statistical methods are described for predicting sensory information given by a sensory panel from external instrumental measurements. The methods are compared in terms of an analysis of variance decomposition of the sensory scores and the importance of utilising the interactions (or individual differences) in the modelling is discussed. The different methods are illustrated by prediction of sensory quality of peas from near infrared reflectance spectroscopy.     

Nonstandard neuropsychological assessment: An illustration.

Administered 2 versions of the Progressive Matrices to 35 patients with unilateral stroke. 12 Ss (mean age 60.9 yrs) had left hemisphere damage, and 23 Ss (mean age 59.6 yrs) had right hemisphere damage. Half of the items were given in standard form; the remaining items were physically rearranged so that the 6 response alternatives were aligned in a single column, eliminating the need for lateral scanning. Ss with unilateral neglect achieved significantly higher scores when the format was modified to minimize the need for lateral scanning. Ss without neglect were largely unaffected by differences in format. (PsycINFO Database Record (c) 2010 APA, all rights reserved)