Design of a discrete Kalman filter for a tactile sensor in a feedback control system

This paper presents a design methodology for the optimum linear filter and predictor applied to robot sensor signals, as well as a sensitivity analysis of the kalman algorithms for uncertainties in the estimation of signal and noise parameters. Simulation of the filtration and prediction processes was made assuming a first-order spectrum of a pure signal and white measurement noise. Calculations of the algorithm errors, dependent on the accuracy of the signal and noise parameter estimation, were done for various spectra of the signal and for various signal-to-noise ratios. Furthermore, the sensitivity curves of the Kalman filter and predictor are presented. The outlined considerations might be helpful for designers when synthesizing optimum linear digital filters applied to sensor signals. Although that particular procedure has been designed for a robot tactile sensor application, the conclusions are more general, and applications may be found elsewhere.     

PROTECTIVE EFFECT OF LYSOSTAPHIN FROM STAPHYLOCOCCUS SIMULANS AGAINST GROWTH OF STAPHYLOCOCCUS AUREUS IN MILK AND SOME OTHER FOOD PRODUCTS

The effect of lysostaphin from Staphylococcus simulans expressed in Escherichia coli TOP10 strain on Staphylococcus aureus used for inoculation of milk, ground pork and mayonnaise salad was investigated. The populations of this pathogen in ultrahigh‐temperature milk preserved at 4C by lysostaphin added up to concentrations of 1.5 or 3.0 µg/mL were reduced by 0.73 and 0.92 log(cfu/mL) in control samples without enzyme addition. The protective influence of lysostaphin was diminished in case of milk storage (20C) prolonged up to 24 h. Furthermore, a final reduction level by 0.92 log(cfu/mL) was achieved after 24 h of pork storage. The smaller and more dependent on enzyme concentration inactivation of S. aureus was observed in the case of the mayonnaise salad, and it led to the conclusion that some food components or proteolytic enzymes originating from other bacteria caused lysostaphin inactivation.     

INFLUENCE OF WATER ACTIVITY ON THE ACOUSTIC PROPERTIES OF BREAKFAST CEREALS

Corn and wheat bran flakes were compressed in a plastic cylinder and the generated vibrations were measured by a piezoelectric accelerometer. Amplitude–time records were thoroughly analyzed and the total acoustic energy in arbitrary units, number of acoustic events and energy of a single acoustic event were calculated. Relationships between the time of compression, frequency and sound intensity are presented as acoustograms. All parameters, except the energy of a single acoustic event, were strongly dependent on water activity (A_w). The flakes differed essentially in their ability to propagate vibrations. At low A_w's, both types of flakes were alike, but at higher A_w's, corn flakes damped high‐frequency waves while wheat bran flakes did not show this property.     

EVALUATION OF ENVIRONMENTAL IMPACT OF AIR POLLUTION SOURCES

This paper addresses the problem of evaluation and comparison of environmental impact of emission sources in the case of a complex, multisource emission field. The analysis is based on the forecasts of a short-term, dynamic dispersion model. The aim is to get a quantitative evaluation of the contribution of the selected sources according to the predefined, environmental cost function. The approach utilizes the optimal control technique for distributed parameter systems. The adjoint equation, related to the main transport equation of the forecasting model, is applied to calculate the sensitivity of the cost function to the emission intensity of the specified sources. An example implementation of a regional-scale, multilayer dynamic model of SO_x transport is discussed as the main forecasting tool. The test computations have been performed for a set of the major power plants in a selected industrial region of Poland.     

Hybrid polymer electrolyte membrane fuel cell–lithium‐ion battery powertrain testing platform – hybrid fuel cell electric vehicle emulator

A testing and validation platform for hybrid fuel cell (FC)–lithium‐ion battery (LIB) powertrain systems is investigated. The hybrid FC electric vehicle emulator enables testing of hybrid system components and complete hybrid power modules up to 25 kW for application in electric light‐duty vehicles, light electric vehicles and so forth. A hybrid system comprising a 10‐kW_el low‐temperature polymer electrolyte membrane FC stack and an 11.5‐kWh LIB pack is installed. The system supplies power to a 20‐kW permanent magnet synchronous motor and a 25‐kW alternating current asynchronous, electrically programmable dynamometer is used to simulate the vehicle load during testing at dynamic drive cycle. The steady‐state performance tests of the direct current (DC) motor, DC/DC converter, low‐temperature polymer electrolyte membrane FC stack and LIB are performed as well as dynamic tests of the complete hybrid system. The Economic Commission for Europe driving cycle is selected as a reference cycle to validate the investigated hybrid FC–LIB powertrain. An efficiency of 83% and 95% is measured for electric motor and DC/DC converter, respectively. An average stack efficiency of 50% is achieved. An average hydrogen consumption of 3.9 g * km^?1 is reached during the Economic Commission for Europe driving cycle test. Copyright © 2017 John Wiley & Sons, Ltd.     

Restoration of kefir grains subjected to different treatments

The aim of the study was to find a way to recover the quality of kefir grains that had been subjected to the following treatments: homogenisation, rinsing the grains with water, freeze‐drying and milling, freezing in liquid nitrogen and then frozen storage, and cool storage. The grains were studied in respect of their later replication in milk, their size and their microbiota composition. The daily transfer of treated kefir grains, except freeze‐dried ones, into fresh milk was effective in respect of the recovery of their growth dynamics, size and microbiota balance. The growth dynamics of grains in milk seems to be a very good indicator of their vital and technological functions.     

A THREE PARAMETER EQUATION FOR FOOD MOISTURE SORPTION ISOTHERMS

A three parameter equation for moisture isotherms was developed and fitted to 31 food sorption isotherms. The GAB and the Peleg's models were fitted to the isotherms for comparison. Residuals and root mean square were used for assessment of the goodness of fit. The proposed equation gives fit to 28 isotherms but not as good as that obtained with the Peleg's model but much better than that found with the GAB model. Nevertheless the new equation gives higher probability of good fit to experimental data than the other two equations tested. Moreover, the new equation gives water content approaching infinity when a_w= 1, a property which is not offered neither by the Peleg's nor the GAB model.     

Comment on ‘Precision tracking control of non-minimum phase systems with zero phase error’

This paper comments on a technical problem arising in the article ‘ Precision tracking control of non-minimum phase systems with zero phase error’ by Xia and Menq.