Effects of ethanol to water ratio in feed solution on the crystallinity of spray-dried lactose

In the present study, the effects of ethanol to water ratio in feed solution on the physical properties of spray-dried alpha-lactose monohydrate were evaluated. Crystallinity of the spray-dried lactose was determined by isothermal microcalorimetry (IMC) and by differential scanning calorimetry (DSC). Water content of the spray-dried lactose was determined by thermogravimetric analysis and the surface area was evaluated by Brunauer, Emmett, and Teller (BET) method. The crystallinity of spray-dried lactose varied from 0% to 100%, depending on the ratio of ethanol to water in the feed solution. Lactose spray dried from pure ethanol was 100% crystalline and contained hydrate water. Lactose spray dried from pure water was 100% amorphous. The feed solution substantially affected the ratio of surface water to hydrate water, as the content of surface water increased and hydrate water decreased, while the crystallinity of spray-dried lactose decreased. Surface area of the spray-dried lactose increased as a function of amorphous content.     

The effects of text structure and prior knowledge of the learner on computer-based learning

This study is an attempt to investigate the effects of document structure and knowledge level of the reader on reading comprehension, browsing, and perceived control. Four types of texts are distinguished, differing in structure (linear text, hierarchical hypertext, mixed hypertext, and generative text). All the materials were on a PC. In all conditions, participants were allowed 1 h to read through the document. After completing the reading part of the experiment, they were asked to fill out the perceived control questionnaire followed by the reading comprehension test. As far as reading comprehension was concerned, knowledgeable participants had higher reading comprehension scores than non-knowledgeable participants only in the linear text. In addition, there were no significant differences in terms of the reading comprehension scores of the knowledgeable participants among the four topologies. However, the performance of non-knowledgeable participants differed with respect to the type of the topology. In particular, non-knowledgeable participants in the hierarchical and generative conditions performed better than those in the other two conditions. With respect to perceived control, the performance of knowledgeable and non-knowledgeable participants was equivalent in all four conditions. The results are discussed in terms of their implications for the computer-based learning.     

Uptake of zinc,nickel, and chromium by N-isopropyl acrylamide polymer gels

Pure N-isopropyl acrylamide (NIPA) polymer gel and NIPA copolymers containing 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-acetamidoacrylic acid (AAA), and acrylic acid (AA) were prepared and evaluated with respect to their capability for taking up zinc, nickel, and chromium ions from solutions. AAA-containing NIPA gels were found to take up these metal ions most efficiently. Titration of these gels verified the strong acidic nature of the AMPS–NIPA gel and the weakly acidic nature of the AA–NIPA and AAA–NIPA gels. The ion-exchange capacities, derived from the titration curves, were, however, rather low in all cases. NIPA gels are known to collapse at temperatures about 32°C. This, however, was found to have no effect on the ion-exchange behavior of the gels. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:355–362, 1998     

The Determination of relative amounts of Phases in Binary Mixtures with Quantitative X-Ray Diffraction

The quantitative x-ray diffraction analysis offers often an exact and practical technique to determine the relative amounts of the phases of the solid in question. The sample may contain only one amorphous phase.

The purpose of this paper is to estimate the suitability of this technique to quantify the phase fractions of pharmaceutical substances. Three different method were used to determine the relative amounts of phases. Methods were compared and the major sources of error were estimated. The measurements and calculations are carried out using selegilin hydrochloride, mannitol and modified starch as an example. The results show that the amount of about 2 % of selegilin hydrochloride can be observed reliably from among the mannitol (crystalline substance) or modified starch (amorphous substance). During the work it became obvious that the accuracy of these calculations can essentially be improved planning the measurements carefully.     

Motives to restructure industries: Finnish evidence of cross-border and domestic mergers and acquisitions

Abstract.  We estimate a multilogit model for the probabilities that a firm will acquire or become a target in different M&A categories, which are defined according to the location of an acquiring firm with respect to a target. We find that certain firm characteristics of an acquiring firm regarded as indicative of having a high capability of monitoring a target – or internalising the potential synergies of M&A – increase the probability of distant M&As at the expense of close M&As. Factors which ease the monitoring of the target firm's value increase the probability that such a firm becomes a target located far from an acquiring firm.     

Investigations of Activation Energy of Porous Silicon Oxidation Using Calorimetric Methods

The oxidation of porous silicon has been studied using differential scanning calorimeter. The oxidation was found to consist of two parts with different activation energies. This indicates the existence of two different reaction mechanism. The results from the hydrogen desorption measurements have been used to study the different oxidation behaviour of the n- and p⁺-type porous silicon. The results show that the dihydride structure dominates on the surface of the n-type porous silicon, contrary to p⁺-type porous silicon, where the monohydride is the major structure. Explanations of these features are discussed. Using the activation energy, the surface termination effects are investigated. The best improvement in the activation energy was observed in the sample, whose surface was partially stabilized by ammonium groups.     

Hygienic level and surface contamination in fresh-cut vegetable production plants

The number of vegetable processing plants has increased during recent years in many countries. At the same time, fresh vegetable products have been implicated by epidemiologic investigations as sources of infection. Fresh vegetables are susceptible to microbial contamination after harvest due to their high water and nutrient contents. Contamination may occur at all stages during production. The aim of this study was to determine the level of surface contamination after cleaning in several fresh-cut vegetable processing plants, and to identify the critical points in the processes and operating rooms. Surface and environmental samples were taken from the plants after cleaning of the processing devices and surfaces. The levels of surface and air hygiene in the vegetable processing factories were determined with different rapid hygiene monitoring methods. The amounts of total aerobic bacteria, Enterobacteriaceae and β-glucuronidase-positive bacteria, yeasts and moulds on surfaces were measured using Hygicult^® contact plates. ATP bioluminescence was measured luminometrically with an HY-LiTE^®2 equipment. The number of microbes in air was measured with an MAS-100 sampler. The highest levels of total aerobic bacteria, yeasts, Enterobacteriaceae and β-glucuronidase-positive bacteria were detected on machines (cutters, peeling machines etc.). High mean values of ATP were detected e.g. on packaging surfaces (due to high values of wooden boxes) and on cutters. Most of the bacterial counts measured on the surfaces were unacceptable when using the Finnish surface hygiene guidelines as criteria. However, the results should be examined in the context of the type of production and the stage of operation also must be taken into account. Different hygiene areas (FDA, 2008) should be separate enough to allow maintenance of good hygiene in cleaner areas while accepting lower hygiene levels e.g. in primary (early) washing steps. Despite this, the results show that there is a clear need to improve cleaning and hygiene practices in vegetable production. Several practical recommendations were given e.g. concerning cleaning, design of production areas, training of employees and self monitoring of surface hygiene. The information obtained will be used for improvement of practices in the cleaning of vegetable processing factories.     

Affective evaluation of user impressions using virtual product prototyping

This study aims to develop an effective and efficient method of analyzing user impressions of a product using virtual prototyping. A method to analyze the relationship between user impressions and design elements of a product using virtual prototyping was proposed, and then the method was applied to the case study of automobile interior design. Thirty‐two participants in the experiment evaluated 32 different virtual prototypes of automobile interiors generated from the combination of 17 design elements. The results of the case study showed that user impressions can be well explained by design elements. Physically large design elements, such as the shapes of frontal area, center fascia, door trim, and steering wheel, were critical areas of automobile interior design. The proposed method is expected to be an effective and efficient alternative for industrial practitioners to analyze user impressions of design alternatives at the early stage of the design process. © 2010 Wiley Periodicals, Inc.