On the challenges of measuring interfacial characteristics of three‐phase fluid flow with x‐ray microtomography

Synchrotron‐based x‐ray computed microtomography contributes high‐resolution, three‐dimensional observations to investigations of multiphase fluid transport in porous media. Pore‐scale observations are valuable to the development and validation of new theory, as well as numerical models. Computed microtomography has been used previously to measure fluid content and interfacial areas in systems containing two fluids (air–water, oil–water) and to a limited extent to measure fluid content and entrapped fluid morphology in systems containing three fluids (air–oil–water). This study addresses challenges that arise when imaging three‐phase flow in spreading systems. The first challenge is related to wettability alteration. Observations reported herein suggest that the wettability of solid surfaces changed over the course of a three‐fluid phase flow experiment, a phenomenon that has not been observed in similar, previously conducted two‐fluid phase experiments. Follow‐up experiments showed that wettability alteration is significant when oil–solid contact is combined with x‐ray exposure, and is not reversed with a conventional cleaning procedure. The second challenge arises in segmenting three‐phase images, and thereby obtaining data from which various measures can be quantified with sufficient accuracy. Partial volume effects and blur often cause the grey‐scale values of different fluids to overlap and appropriate steps must be taken to avoid ambiguity at phase boundaries. A comparison of images collected at standard resolution (10.6 microns voxel^–1) to those collected at a higher resolution (5.3 microns voxel^–1) showed that saturation measurements are within 5% of each other, but interfacial areas for three‐phase systems may be underestimated at standard resolution by as much as 25%.     

Taking Stock: An Analysis of the Publishing Record as Represented by the Journal of Engineering Education

The Journal of Engineering Education emerged in the engineering education community in 1993 as a continuation of the American Society of Engineering Education's journal, Engineering Education. The Journal of Engineering Education was to play a role in the broadening of engineering education culture by helping to bring the scholarship of engineering education to the same level of respect and recognition in the faculty reward system as traditional scholarship in engineering sciences. In doing so, the journal hoped to keep pace with and encourage the significant changes in engineering education needed to prepare for the challenges of 21st century practice. This paper discusses the engineering education environment as reflected in six years of papers published in the Journal of Engineering Education from 1996 to 2001. Topics of papers are identified, along with changes and trends in these topics during the six‐year period. In addition, characteristics of particularly convincing papers are enumerated and discussed. This paper is offered as a summary and review of this six‐year body of work on engineering education and should aid the engineering education community in reflecting on the success of the Journal in promoting and encouraging the scholarship of teaching.     

Electrochemical characterization of Fe-Ni-P alloy electrodeposition

In this study we have investigated the electrodeposition of amorphous iron–nickel–phosphorus alloys from a sulfate electrolyte. Fe-Ni alloys are known to exhibit an anomalous type of plating behaviour in which deposition of the less noble metal is favoured. We have found that the codeposition of phosphorus from hypophosphite in the electrolyte led to a reversal to a normal behaviour. This reversal was due both to the suppression of iron and enhancement of nickel partial currents. The overall deposition process is dominated by the hydrogen evolution reaction. This is exacerbated by the low pH needed to codeposit sufficient phosphorus to achieve an amorphous structure.     

Sequence Analysis of the Candida albicans ADE2 Gene and Physical Separation of the Two Functionally Distinct Domains of the Phosphoribosylaminoimidazole Carboxylase

An ADE2 genomic clone from the pathogenic fungus, Candida albicans, was isolated by complementation of an Escherichia coli purK mutant and the gene was analysed by DNA sequencing. A 1707 bp open reading frame was identified encoding a polypeptide of 569 amino acids with significant homology to all the known yeast ADE2 genes. Sequence homology to both the E. coli purE and purK genes suggests that the C. albicans ADE2 gene is the result of an evolutionary fusion. The amino-acid sequence comparison showed that the N-terminal domain of the Ade2 protein has a 52·5% identity to PurK, whereas the C-terminal domain has a distinct 64·3% identity to PurE. In order to establish the functional relationship of these two regions, deletion mutants of the Ade2 protein were prepared by recombinant expression of the functional domains, which were tested by complementation of their respective E. coli auxotrophs. The sequence described in this paper has been deposited in the EMBL data library under the Accession Number U69606. © 1997 John Wiley & Sons, Ltd.     

Inhibition of spoilage lactic acid bacteria by lysozyme during wine alcoholic fermentation

The efficacy of lysozyme against indigenous lactic acid bacteria (LAB) and four inoculated spoilage LAB cultures was investigated in laboratory scale Chardonnay winemaking trials (at pH 3.8). These LAB cultures included Lactobacillus kunkeei, Lactobacillus brevis, Pediococcus parvulus , and Pediococcus damnosus . Three concentrations of lysozyme were used: 0, 125 and 250 mg/L. Alcoholic fermentation of the grape juice was carried out at 20±0.5°C using Saccharomyces cerevisiae . Lysozyme did not have any negative impact on yeast growth and sugar reduction. This enzyme was found to be very effective in inhibiting the growth of all four LAB cultures investigated. Under the given experimental conditions, as high as an 8 log cell reduction was obtained for some of the strains. The acetic acid production by L. brevis and L. kunkeei was significantly reduced in the treatments with 125 and 250 mg/L lysozyme added ( P < 0.01). The effect of lysozyme on the cells of the LAB cultures was examined under a scanning electron microscope. It is evident that lysozyme had a detrimental impact on the cells of these cultures. Based on these observations, it is concluded that lysozyme may be a useful tool for winemakers to control the growth of spoilage LAB and to reduce the production of volatile acids. The addition of lysozyme may also prevent the increase of volatile acidity during stuck/sluggish alcoholic fermentation. This tool is particularly useful in high pH wines where SO₂ is less effective.     

AMINO ACID, FATTY ACID, CHOLESTEROL AND OTHER STEROLS ANALYSES OF DIFFERENT PIZZA FORMULATIONS

The protein content of many food products may be enriched by the addition of protein concentrates. Textured vegetable protein (TVP) and single cell protein (SCP) were added in varying amounts to a pizza formulation and stored at -20°C until used. The fabricated pizzas were analyzed for amino acids, total fat, fatty acids, sterols, water, protein, ash and cis, cis-methylene interrupted polyunsaturated fatty acids. The addition of TVP and SCP increased the protein content by an average of 18%. Certain amino acids, such as lysine, arginine, leucine and threonine, were significantly increased with the addition of TVP and SCP. The fat values were generally lower in pizzas with TVP and SCP, and the ash content increased. The moisture content ranged from 46 to 49%, except for the “beef + 5% SCP in crust” which was 41%. The fatty acid and sterol profiles were generally very similar.     

IMPROVEMENT OF MUNICIPAL PURCHASING MANAGEMENT WITH AN AUTOMATED,USER-COMPATIBLE SYSTEM

The availability of timely, accurate information is vital to effective management decision making. Many of the information processing operations performed by a municipal purchasing department in acquiring materials and services may be performed by a well-designed and user-compatible computer system which integrates the functions of purchasing and inventory management. Additionally, such a system provides for the desirable features of accountability and audit trails. A management overview of the design goals, capabilities and operating procedures of a system installed in a large Texas city are presented. The interactive system has been developed to allow its transfer to other municipalities and use by persons not experienced with computers. Included are extensive error-checking and direction-giving features and several levels of documentation which assist personnel in correct, efficient use of the system. The Purchasing and Inventory Control (PIC) system may significantly increase the ability of purchasing management to acquire materials faster and at lower costs, and to present the city council with more timely, accurate reports, most of which are computer generated.