Volatile Fatty Acids in Some Brands of Whisky, Cognac and Rum

SUMMARY— Gas chromatography was applied to eight different types of whisky, two of cognac, one of brandy, and four of rum to determine the relative proportions of volatile fatty acids; with the lower molecular acids as free acids, but upwards from caprylic acid as methyl esters. Acetic acid and the total amount of volatile acids were measured quantitatively. Rum contained the largest amount of volatile acids, 600 mg/L, while one of the brands of Scotch whisky contained the least, 90 mg/L. Acetic acid represented 40–95% of the total amount of volatile acids in the whisky; for cognac and brandy, the value was .50–75%, and for rum 75–90%. The relative amounts have been reported for 21 acids, with acetic acid excluded. Capric, caprylic and lauric acid were the main components in whisky, cognac and brandy. Of the beverages analyzed, rum contained the largest quantity of lower fatty acids, particularly propionic and butyric acid; the main component of Jamaican rum was propionic acid. The main components of the group of long-chain fatty acids were myristic, palmitic and palmitoleic acids. Scotch whisky contained equal amounts of palmitic and palmitoleic acid; palmitoleic acid regularly appeared in smaller amounts in the other beverages     

Production management as a constraint satisfaction problem

Production management problems can be quite straightforwardly presented as constraint satisfaction problems, where values for some variables are searched for under a set of constraints. A combination of an operation and a resource is usually interpreted as the variable, and a time window is usually interpreted as the value to be searched for. This convention is challenged. A case is considered where the most appropriate interpretation treats the combination of a resource and a time window as the variable, and an operation as the value. A third possible interpretation is also briefly covered, where the combination of an operation and a time window is the variable, and the resource is the value.     

Registration of phase‐contrast images in propagation‐based X‐ray phase tomography

X‐ray phase tomography aims at reconstructing the 3D electron density distribution of an object. It offers enhanced sensitivity compared to attenuation‐based X‐ray absorption tomography. In propagation‐based methods, phase contrast is achieved by letting the beam propagate after interaction with the object. The phase shift is then retrieved at each projection angle, and subsequently used in tomographic reconstruction to obtain the refractive index decrement distribution, which is proportional to the electron density. Accurate phase retrieval is achieved by combining images at different propagation distances. For reconstructions of good quality, the phase‐contrast images recorded at different distances need to be accurately aligned. In this work, we characterise the artefacts related to misalignment of the phase‐contrast images, and investigate the use of different registration algorithms for aligning in‐line phase‐contrast images. The characterisation of artefacts is done by a simulation study and comparison with experimental data. Loss in resolution due to vibrations is found to be comparable to attenuation‐based computed tomography. Further, it is shown that registration of phase‐contrast images is nontrivial due to the difference in contrast between the different images, and the often periodical artefacts present in the phase‐contrast images if multilayer X‐ray optics are used. To address this, we compared two registration algorithms for aligning phase‐contrast images acquired by magnified X‐ray nanotomography: one based on cross‐correlation and one based on mutual information. We found that the mutual information‐based registration algorithm was more robust than a correlation‐based method.     

Single particle raster image analysis of diffusion for particle mixtures

Recently we complemented the raster image correlation spectroscopy (RICS) method of analysing raster images via estimation of the image correlation function with the method single particle raster image analysis (SPRIA). In SPRIA, individual particles are identified and the diffusion coefficient of each particle is estimated by a maximum likelihood method. In this paper, we extend the SPRIA method to analyse mixtures of particles with a finite set of diffusion coefficients in a homogeneous medium. In examples with simulated and experimental data with two and three different diffusion coefficients, we show that SPRIA gives accurate estimates of the diffusion coefficients and their proportions. A simple technique for finding the number of different diffusion coefficients is also suggested. Further, we study the use of RICS for mixtures with two different diffusion coefficents and investigate, by plotting level curves of the correlation function, how large the quotient between diffusion coefficients needs to be in order to allow discrimination between models with one and two diffusion coefficients. We also describe a minor correction (compared to published papers) of the RICS autocorrelation function.     

Active wear and failure mechanisms of TiN-Coated high speed steel and tin-coated cemented carbide tools when machining powder metallurgically made stainless steels

In this study, active wear and failure mechanisms of both TiN-coated high speed steel and TiN-coated cemented carbide tools when machining stainless steels made by powder metallurgy in low and high cutting speed ranges, respectively, have been investigated. Abrasive wear mechanisms, fatigue-induced failure, and adhesive and diffusion wear mechanisms mainly affected the tool life of TiN-coated high speed steel tools at cutting speeds below 35 m/min, between 35 and 45 m/min, and over 45 m/min, respectively. Additionally, fatigue-induced failure was active at cutting speeds over 45 m/min in the low cutting speed range when machining powder metallurgically made duplex stainless steel 2205 and austenitic stainless steel 316L. In the high cutting speed range, from 100 to 250 m/min, fatigue-induced failure together with diffusion wear mechanism, affected the tool life of TiN-coated cemented carbide tools when machining both 316L and 2205 stainless steels. It was noticed that the tool life of TiN-coated high speed steel tools used in the low cutting speed range when machining 2205 steel was longer than that when machining 316L steel, whereas the tool life of TiN-coated cemented carbide tools used in the high cutting speed range when machining 316L steel was longer than that when machining 2205 steel. formerly with the Laboratory of Engineering Materials, Helsinki University of Technology     

From static micrographs to particle aggregation dynamics in three dimensions

Studies on colloidal aggregation have brought forth theories on stability of colloidal gels and models for aggregation dynamics. Still, a complete link between developed frameworks and obtained laboratory observations has to be found. In this work, aggregates of silica nanoparticles (20 nm) are studied using diffusion limited cluster aggregation (DLCA) and reaction limited cluster aggregation (RLCA) models. These processes are driven by the probability of particles to aggregate upon collision. This probability of aggregation is one in the DLCA and close to zero in the RLCA process. We show how to study the probability of aggregation from static micrographs on the example of a silica nanoparticle gel at 9 wt%. The analysis includes common summary functions from spatial statistics, namely the empty space function and Ripley's K‐function, as well as two newly developed summary functions for cluster analysis based on graph theory. One of the new cluster analysis functions is related to the clustering coefficient in communication networks and the other to the size of a cluster. All four topological summary statistics are used to quantitatively compare in plots and in a least‐square approach experimental data to cluster aggregation simulations with decreasing probabilities of aggregation. We study scanning transmission electron micrographs and utilize the intensity – mass thickness relation present in such images to create comparable micrographs from three‐dimensional simulations. Finally, a characterization of colloidal silica aggregates and simulated structures is obtained, which allows for an evaluation of the cluster aggregation process for different aggregation scenarios. As a result, we find that the RLCA process fits the experimental data better than the DLCA process.     

On the role of information in decentralized macro-economic stabilization†

This paper deals with the so-called timing problem in macro-economic stabilization. A simple linear model of the U.S. economy is considered and the decision-making is assumed to be decentralized with the two independent control agents being the monetary and the fiscal authorities. The timing problem is due to the fact that the Central Bank is able to update the monetary policy decisions rapidly, whereas the fiscal policy decisions, which are made by Congress, are inflexible and cannot usually be re-evaluated with respect to the value of the system state at short time intervals. A general analysis of the effects of timing differences is performed. The problem formulation results in non-zero-sum difference games with periodic open-closed information structures. The Nash equilibrium solution concept is assumed. The results suggest that the fiscal losses are relatively insensitive the changes in the policy updating intervals when the fiscal agent is assigned to stabilize deviations in the domestic production. A completely opposite behaviour is observed when the assignments to targets are interchanged.     

The Aura of the Digital

The focus on computation in design is largely on technique, with designers everywhere now using the computer as a tool for aiding design and manufacture. Here, interactive media designer Jussi Ängeslevä shifts the emphasis on computation from design method to ‘meaning making’. He highlights how the work of his practice, Berlin-based ART+COM, transfers digital thinking in such a way as to express experience unfolding in space.     

Examination of Sugars, Sugar Alcohols, and Artificial Sweeteners as Substitutes for Sucrose in Strawberry Jam. Keeping Quality Tests

The keeping quality of the low sugar strawberry jams was tested during 10 months' storage at room and refrigerator temperature (5°C) according to physical color and texture measurements, and by sensory analysis. In general sorbitol and xylitol jams and many of the jams containing some percentage of xylitol kept either better than or as well as the conventional sucrose jam. The color, taste and preference of HFS and fructose jams deteriorated sooner than those of most other jams during storage. When xylitol was used with fructose and HFS the changes in the characteristics studied were retarded. During storage the xylitol-maltodextrin jams became crystallized and were unfit for sensory evaluation.