Influence of the malting parameters on the haze formation of beer after filtration

Malting changes the chemical and enzymatical composition of barley. During malting, enzymes are synthesized, cell walls (pentosans, proteins, etc.) degraded and starch becomes available for enzymatic attack. The progress of germination defines the final beer quality and processability in several aspects: mouthfeel, foam and haze formation (different proteins), processability (viscosity caused by certain substances, like β-glucan), fermentation progress (FAN, sugar content), etc. The objective of this research was to study the influence of different modified malt on turbidity in beer after filtration. This was achieved by analyzing selected malts at different germination stages and afterward studying their influence on the final beer composition, focusing on protein content and composition. Protein fractions were analyzed using a Lab-on-a-Chip technique, which separates the proteins—based on their molecular weight—by capillary electrophoresis. This analysis was supported by the use of two-dimensional gel electrophoresis (2D-PAGE). Additionally, common malt and beer analyses and turbidity and filterability measurements were performed. The protein composition could be followed from malt to beer with both the Lab-on-a-Chip technique and 2D-PAGE. No differences in protein composition could be seen in the final protein composition of the beer. However, it could be observed, with Lab-on-a-Chip technique, that high amounts of a protein fraction with a size of 25–28 kDa caused increased turbidity in the beer.     

Multiplierless Mumford and Shah Functional Implementation

This paper proposes the implementation of the Mumford and Shah functional without using complex operations such as multiplications and divisions. Our goal is to show that the achieved results in terms of performance/complexity trade-off are well suited for video applications of the Mumford and Shah functional, such as motion estimation based on segmentation techniques. To this purpose, two implementations, with and without multiplications, have been developed and ported on a DSP board that can get frames from a camera and play out the results on a standard VGA monitor: reported results show a relative speed-up of a factor of 3 for the multiplierless version with no visual quality degradation.     

Population balance model for drying of droplets containing aggregating nanoparticles

Drying of droplets containing nanoscaled particles is investigated for the first drying stage by means of a population balance model. The novelty of the model consists in the consideration of not only gas‐side heat and mass transfer, and liquid‐side diffusion, but also aggregation as a particulate process. Size‐dependency of particle mobility links liquid‐side mass transport and aggregation, leading to different particle concentration profiles in the droplet depending on the thermal conditions and aggregation kinetics. The main focus of this work lies on the influence of the aggregation kinetics on the profiles, the time of crust formation and the resulting droplet porosity at the end of the first drying stage. Model validation and justification is performed by use of experimental data from literature. © 2012 American Institute of Chemical Engineers AIChE J, 2012     

Modelling respirometric tests for the assessment of kinetic and stoichiometric parameters on MBBR biofilm for municipal wastewater treatment

Moving Bed Biofilm Reactor (MBBR) technology is a suitable option for up-grading and retro-fitting wastewater treatment plants. Although being introduced in late 80s, design and operational guidelines of MBBR are mainly based on empirical approaches. This work was aimed to assess the biokinetics on both detached and undisturbed biofilm samples from a large pilot-scale MBBR treating pre-settled municipal wastewater. Experimental OUR profiles of heterotrophic biomass in detached and undisturbed biofilm have been obtained with respirometric tests and then modelled with an extended version of ASM3 which assumes biomass growth to take place on both readily biodegradable substrate and storage products. Results indicated the storage mechanism to be prevalent for heterotrophic biomass growth, with a 80% fraction of soluble substrate converted into storage products. The active heterotrophic biomass in the film was estimated in detached biofilm samples; on average, it corresponded to a 39% fraction of particulate COD. Tests on undisturbed biofilm were carried out to quantify autotrophic ammonia and nitrite removal, showing an effective specialisation of the nitrifying biomass. The parameters obtained could support a more rational design approach for the moving-bed biofilm process.     

Scenario-based touching: on the influence of top-down processes on tactile and visual appreciation

The aim was to propose a testing procedure that allows measuring ecological valid judgments as a tool for selecting e.g. surface materials in the design process. Precise measures are essential for evaluation processes for example in design research and applied studies. Contextual effects in form of top-down processes often lead to biases in measures such as quality or liking judgments. We examined contextual effects of such factors by varying specific instructions, which were based on everyday life scenarios. We also investigated the stability and ecological validity of evaluations with the focus on a multisensory approach involving vision plus touch, touch-only and vision-only conditions. Participants evaluated the materials, for preference in experiment 1, and for perceived material properties (thermal conductivity, hardness and roughness) in experiment 2—either with or without specific instructions. Results showed higher consistency in the vision plus touch condition than in the unimodal conditions. Moreover, preferences and perceived material properties strongly varied according to the presence and the content of instruction (scenarios). These results demonstrate the strong impact of top-down processes on tactile as well as visual judgments.     

Comparison of the antioxidant capacity and the antimicrobial activity of black and green tea

Tea is a common beverage. The green tea is preferentially recommended for its strong antioxidant properties and also for its antimicrobial activity. The antioxidant capacities of 30 samples (black and green tea) were determined by the chemiluminescent Trolox equivalent antioxidant capacity (TEAC) determination. The average value of TEAC of the non-fermented (green tea) and semi-fermented tea samples was 1.43 mM and the average value of TEAC of the fermented teas (black tea) samples was 1.43 mM. All samples were stored in freezer (?20 °C) and the TEAC determination was repeated after a year. The average values of TEAC of non-fermented and semi-fermented tea samples were twofold lower in comparison to fermented tea samples and only 20% of average value of TEAC of the fresh tea infusion. The parallel determinations of minimal inhibitory concentration (MIC) on gram-positive and gram-negative bacterial strains (Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli) were done. Also the MIC was possible to determine after a year. The assumed prevailing antioxidant and antimicrobial activities of non-fermented tea infusions were not confirmed as well as the dominant antioxidant and antimicrobial properties of specific type of tea infusion.     

Efficacy of virtual patients in medical education: A meta-analysis of randomized studies

A meta-analysis was performed to assess the Effect Size (ES) from randomized studies comparing the effect of educational interventions in which Virtual patients (VPs) were used either as an alternative method or additive to usual curriculum versus interventions based on more traditional methods.     

Polyaniline synthesis with iron(III) chloride–hydrogen peroxide catalyst system: Reaction course and polymer structure study

We report on the catalytic polymerization of aniline (ANI) with FeCl₃/H₂O₂ system, which can considerably lower contamination of neat polyanilines (PANIs) by side-products characteristic of stoichiometric polymerization. However, catalytically prepared PANIs exhibit reduced conductivity related most probably to side reactions involving radicals generated as integral components of the FeCl₃/H₂O₂ system. Catalytic polymerization of ANI with FeCl₃/H₂O₂ system was found to be the reaction of approximately 2nd order with respect to ANI and gives PANIs of a good quality only when [H₂O₂] in the reaction mixture was kept low, i.e., at under-stoichiometric ratios [H₂O₂]/[ANI]. At over-stoichiometric ratio [H₂O₂]/[ANI], PANIs of lowered conductivity, worse spectroscopic characteristics and increased size of PANI nanostructures were obtained; nevertheless, these PANIs were not over-oxidized to pernigraniline state. The reaction-time profiles of the open-circuit potential of reaction mixtures exhibited an inflection related to the H₂O₂ depletion from the system. Total consumption of H₂O₂ exceeded its consumption necessary on ANI polymerization, which proves partial decomposition of H₂O₂ by Fe ions. UV/vis and resonance Raman spectra indicate incomplete deprotonization of PANIs prepared with FeCl₃/H₂O₂ system and subsequently treated with aqueous ammonia, which proves partial self-doping of these PANIs. However, IR and NMR spectra indicate rather low extent of self-doping. It has been proposed that self-doping of PANI involves phenolic OH groups originated from side reactions involving radical species formed from H₂O₂.