Rapid identification and classification of bacteria by 16S rDNA restriction fragment melting curve analyses (RFMCA)

The aim of this work was to evaluate restriction fragment melting curve analyses (RFMCA) as a novel approach for rapid classification of bacteria during food production. RFMCA was evaluated for bacteria isolated from sous vide food products, and raw materials used for sous vide production. We identified four major bacterial groups in the material analysed (cluster I-Streptococcus, cluster II-Carnobacterium/Bacillus, cluster III-Staphylococcus and cluster IV-Actinomycetales). The accuracy of RFMCA was evaluated by comparison with 16S rDNA sequencing. The strains satisfying the RFMCA quality filtering criteria (73%, n=57), with both 16S rDNA sequence information and RFMCA data (n=45) gave identical group assignments with the two methods. RFMCA enabled rapid and accurate classification of bacteria that is database compatible. Potential application of RFMCA in the food or pharmaceutical industry will include development of classification models for the bacteria expected in a given product, and then to build an RFMCA database as a part of the product quality control.     

Reduction kinetics of commercial haematite pellet in a fixed bed at 1123–1273 K

In the present study a model for future use in the modelling of moving bed direct reduction reactors has been developed. The model of a fixed bed reactor for the production of sponge iron from haematite incorporates both heat- and mass-transfer, as well as the chemical reduction rate. The model results were compared to the experimental data obtained from a lab scale reactor in the temperature range 1123–1273?K, as well as to the output from a simple model assuming isothermal conditions. The H₂/CO ratio (β) of the reducing gas was in all cases varied from 0.8 to 2.0. Overall the non-isothermal model developed permits a more accurate representation of the experimental data than the isothermal estimates, with a typical discrepancy of only 1.3%.     

Thermogravimetric relaxation study of the proton conductor lanthanum tungstate,La28−xW4+xO54+δv2−δ, x = 0.85

Diffusion- and surface exchange coefficients for incorporation and transport of protons and water in lanthanum tungstate, La_27.15W_4.85O_55.28v_0.73 have been determined from thermogravimetric relaxation. Tracer diffusion of protons has proved to be considerably faster than chemical diffusion of water, whereas the tracer surface exchange process is somewhat slower than its chemical counterpart. Consequently, tracer relaxations display larger critical thicknesses than the chemical ones and are moreover found to be predominantly surface controlled. The activation energy of the chemical diffusion coefficient changes above 700 °C and this transition and a corresponding change in its water vapor dependency are discussed in light of chemical diffusion of water. The activation energy of the chemical surface exchange coefficient under reducing conditions is the half of that under oxidizing. Platinum nano particles have proved to increase the rate of water incorporation under reducing conditions.     

Electromagnetically Modified Filtration of Aluminum Melts—Part I: Electromagnetic Theory and 30 PPI Ceramic Foam Filter Experimental Results

In the present work, laboratory-scale continuous filtration tests of liquid A356 aluminum alloy have been performed. The tests were conducted using standard 30 PPI (pores per inch) ceramic foam filters combined with magnetic flux densities (~0.1 and 0.2 T), produced using two different induction coils operated at 50 Hz AC. A reference filtration test was also carried out under gravity conditions, i.e., without an applied magnetic field. The obtained results clearly prove that the magnetic field has a significant affect on the distribution of SiC particles. The influence of the electromagnetic Lorentz forces and induced bulk metal flow on the obtained filtration efficiencies and on the wetting behavior of the filter media by liquid aluminum is discussed. The magnitudes of the Lorentz forces produced by the induction coils are quantified based on analytical and COMSOL 4.2^® finite element modeling.     

On the numerical solution of non-linear reservoir flow models with gravity

Based on a two-phase fluid model for immiscible displacement in a porous medium, we develop and analyse numerical solution techniques for certain non-linear phenomena. Two different solution strategies for the treatment of gravity effects, which are non-trivial to model by existing solution techniques and may be of great influence in many practical flow situations, are presented. The solution procedures are based on an operator-splitting technique, combining the modified method of characteristics with finite element techniques and adaptive grid refinement.     

Involving users in the development of a modeling language for customer journeys

Software and Systems Modeling - Although numerous methods for handling the technical aspects of developing domain-specific modeling languages (DSMLs) have been formalized, user needs and usability...     

Staphylococcus aureus and Listeria monocytogenes in Norwegian raw milk cheese production

The aim of this study was to survey the presence of Staphylococcus aureus and Listeria monocytogenes during the cheese making process in small-scale raw milk cheese production in Norway.The prevalence of S. aureus in bovine and caprine raw milk samples was 47.3% and 98.8%, respectively. An increase in contamination during the first 2-3 h resulted in a 73.6% prevalence of contamination in the bovine curd, and 23 out of 38 S. aureus-negative bovine milk samples gave rise to S. aureus-positive curds. The highest contamination levels of S. aureus were reached in both caprine and bovine cheese after 5-6 h (after the first pressing). There was no contamination of L. monocytogenes in caprine cheeses and only one (1.4%) contaminated bovine cheese.This work has increased our knowledge about S. aureus and L. monocytogenes contamination during the process of raw milk cheese production and gives an account of the hygiene status during the manufacture of Norwegian raw milk cheeses.