Tracking of moving interfaces in sedimentation processes using electrical impedance tomography

Sedimentation monitoring is widely used to control and optimize industrial processes. In this paper we propose a novel computational method for sedimentation monitoring using electrical impedance tomography (EIT). EIT measurements consist of electric current and voltage measurements that are made on the surface of the sedimentation tank and therefore they do not interfere with the sedimentation process. The proposed computational method is based on shape estimation and state estimation formulation of the EIT problem. The sedimentation is parameterized by the locations of the phase interfaces and conductivities of the phase layers. Three different evolution models for the state parameters are considered and the state estimates are computed using the extended Kalman filter algorithm. The performance of the method and the models are evaluated using simulated data from a six electrode EIT measurement configuration. From the results a promising performance of the method can be seen.     

Simple parameterizations of the radiation budget of uniform broadleaved and coniferous canopies

Simulations of the different components of the spectral radiation budget of structurally simple leaf and shoot canopies with varying canopy leaf area index (LAI) were performed. The aims were (1) to test a proposed parameterization of the budget using two spectrally invariant canopy structural parameters (p and p_t) governing canopy absorption and transmittance, respectively, and (2) to incorporate the effect of within-shoot scattering in the parameterization for shoot canopies. Results showed that canopy spectral absorption and scattering were well described by a single parameter, the canopy p value or ‘recollision probability’, which was closely related to LAI. The relationship between p and LAI was however different in leaf and shoot canopy: e.g., at the same LAI the recollision probability was larger in the shoot canopy. It was shown that the p value of the shoot canopy could be decomposed into the p value of an individual shoot (p_sh) and the p value of the leaf canopy with the same effective LAI (LAI_e). The canopy p value allows calculation of canopy absorption and scattering at any given wavelength from the leaf (or needle) scattering coefficient at the same wavelength. To calculate canopy reflectance, separation of the downward and upward scattered parts is needed in addition. The proposed parameter p_t worked rather well in the leaf canopy at moderate values of LAI, but not in the coniferous shoot canopy nor at high values of LAI. However, the simulated fraction of upward scattered radiation increased in a straightforward manner with LAI, and was not particularly sensitive to the leaf (or needle) scattering coefficient. Judged by this ‘smooth’ behavior, the existence of another kind of simple parameterization for this separation remains an interesting possibility.     

Flexographic Printing of Trametes versicolor Laccase for Indicator Applications

Trametes versicolor laccase papers were prepared, and their suitability was tested for anticounterfeiting and oxygen indicator concepts in packaging applications. Laccase was coated and printed onto paper with a flexographic ink base, a sulfo polyester resin, Hydro‐Rez 1100D (HZ1100D). Laccase remains active on paper with flexographic ink HZ1100D after printing with flexographic press. Colour change of papers was observed when 2,2‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS) solution was applied to the paper. A strong colour change to dark green was obtained on the papers prepared by coating or printing of laccase with HZ1100D onto EUCA paper. EUCA paper appeared to be well suited for laccase‐based indicator applications because it remained rough even after ink deposition, allowing rapid absorption of ABTS solution. Finally, the indicators demonstrated to work as oxygen indicators in a package. Indicator colour was changed when oxygen was leaked to the package. As a conclusion, the laccase papers described here would be well suited for various indicator applications and could be produced using flexographic printing, allowing large scale manufacturing. Copyright © 2014 John Wiley & Sons, Ltd.     

Biomechanical evaluation of heavy tool-handling in two age groups of firemen.

The biomechanical load of a rescue-clearing task (lifting a power saw from the floor up to the ceiling level) was evaluated with six older (47 +/- 5 years) and seven younger firemen (32 +/- 2 years). The mean dynamic compressive force at the L5/SI disc was 5998 N for the older subjects and 6392 N for the younger subjects. The peak torques for the back and knee extensions were about equal for the two groups of the subjects. The younger subjects had a significantly higher movement speed in the knee extension than the older subjects (89.1 +/- 25.7 vs. 35.3 +/- 11.5 degrees/s, p less than 0.001). The results showed that lifting a power saw produced a high load on the musculoskeletal system, and that the load was not influenced by age.     

Physiological strain during kitchen work in relation to maximal and task-specific peak values

Six female and three male subjects from a hospital kitchen volunteered for the study. The subjects were working on a conveyor belt collecting and sorting dirty plates, glasses and cutlery for cleaning. In the study, a medical examination, a maximal clinical exercise test with a 12-lead electrocardiogram (ECG) and a maximal arm cranking test were performed in the laboratory. Further, each subject was studied for 30 min during a normal work shift in the kitchen. Oxygen uptake (VO2) and heart rate (HR) were continuously registered. During the work period, a rating of perceived exertion (RPE) was asked at the 5th, 15th and 30th minute. Physiological responses were measured by a portable system (K4) both in the laboratory and in the field. VO2 and HR measured in the field were proportioned to corresponding maximal values during cycling and to peak values during arm-cranking. The mean VO2 for the male and the female subjects during kitchen work was 0.65 +/- 0.16 l min-1. This corresponded to 24% of VO2max and to 41% of VO2peak during arm-cranking. The difference was significant (p < 0.001). Owing to a magnetic field at the conveyor belt, reliable HR values were obtained only from the female subjects. The mean HR during work among the female subjects was 101 beats min-1. It corresponded to 55% of HRmax and 67% of HRpeak during arm-cranking (p < 0.05). The present study shows that the relative work intensity is markedly higher when it is expressed relative to the corresponding muscle group's VO2peak instead of the VO2max. Similar difference was also seen in the HR response. More task-specific testing of physical capacity may provide improved evaluation of physical strain in a job.     

Identification of β-lactam antibiotics using bioluminescent Escherichia coli and a support vector machine classifier algorithm

We propose the use of bioluminescent whole cell biosensor combined with a pattern classification algorithm to automatically detect and identify β-lactam antibiotic substances. Escherichia coli cells with a plasmid harboring luxCDABE genes under the β-lactam sensitive promoter element are used as sensors. We present experimental measurements of light production of bioluminescent bacteria subject to 11 antibiotic substances. The patterns of measured light production are classified using a support vector machine classifier. The accuracy and reliability of the classification suggests that this method can be used in the future to probe for new antibiotic substances.     

Printed electronic switch on flexible substrates using printed microcapsules

Printed electronics, the manufacturing of electronic components on large, flexible, and low-cost substrates by printing techniques, can facilitate widespread, very low-cost electronics for consumer applications and disposable devices. New technologies are needed to create functional components in this field. This paper introduces a new method to create an all-additive printed switch on flexible substrate materials, such as polymer foils and paper substrates. The active layer of the switch component consists of neutral polyaniline (PANI), which can be doped by acid to induce a shift from a non-conductive to a conductive oxidation state. Monodisperse core–shell microcapsules containing an acidic aqueous core liquid were produced by a novel inkjet-based encapsulation technology. It was shown that unfavorable water evaporation from the microcapsules could be reduced by the addition of calcium chloride to the core liquid. A switch component was prepared, consisting of inkjet-printed interdigitated silver electrodes, PANI active layer and printed microcapsules. If an external pressure was applied, for instance with a finger, then the switch component changed its state from non-conductive to conductive with a simultaneous distinct color change. The results clearly demonstrate the feasibility of the presented approach to create either a visual or electronic signal for use in printed electronic applications.     

Design of a linearly assisted switcher for a supply modulated RF transmitter

A broadband modulated power supply for envelope tracking or polar RF transmitters has been built. To study the design constraints, an efficient state-based simulation tool was developed. Based on the simulations, a prototype supply was built. It can deliver up to 1 W (6 V, 150 mA) to a resistive load of 30 ohms with spectral purity of ca. −45 dBc. The power efficiency using a QAM-signal is 49%.     

Scale-up of manufacturing of printed enzyme electrodes for enzymatic power source applications

Production of printable enzymatic power sources was scaled up from laboratory to roll-to-roll (R2R) pilot production. The anode and cathode enzymes were glucose oxidase (GOx) and laccase, respectively. The best laboratory-scale cells had a maximum power and energy density of 1.4 ± 0.1 µW cm^?2 and 5.5 ± 0.2 µWh cm^?2, respectively. These values are 5 and 28 times higher compared to our previously published values. The R2R-produced cells had a maximum power and energy density of 0.40 ± 0.03 µW cm^?2 and 0.6 ± 0.1 µWh cm^?2, respectively. This is 11 % of the best laboratory manufactured cells. It is suspected that the decrease in electrochemical performance originates from the lower mediator amount and higher drying temperature than that of the laboratory produced cells. However, the trials conducted in this work showed that printed enzymatic active layers can be fabricated and dried with a rotary screen-printing machine in R2R process. Hence, fully printed GOx//laccase power sources could be produced from R2R on a large scale for printed electronics applications.     

Film formation and surface properties of enzymatically crosslinked casein films

The use of renewable materials as barrier material is currently intensively investigated. Biopolymers such as polysaccharides, lipids, and proteins have been studied as barrier materials. Protein‐based films often possess good gas barrier properties, but because of their hydrophilic nature the gas barrier properties are sensitive to humidity. The improvement of the properties of sodium caseinate barrier films in potential packaging applications was studied by investigating the effects of enzymatic treatment and plasticizer on the film properties. Oxidoreductases Trametes hirsuta laccase (ThL) and Trichoderma reesei tyrosinase (TrTyr) were compared with transglutaminase for crosslinking of the sodium caseinate molecules in the films and coatings. All of the studied enzymes were able to crosslink sodium caseinate. Film solubility tests, protein electrophoresis, contact angle measurements, and atomic force microscopy studies showed that TrTyr treatment results in sodium caseinate films and coatings with better overall properties compared to treatment with ThL. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011