European intercomparison on electron spin resonance identification of irradiated foodstuffs

The results of a co-trial organized by the Community Bureau of Reference on the use of Electron Spin Resonance spectroscopy for the identification of irradiated food in 21 laboratories are presented. The trial was qualitative on beef and trout bones, sardine scales, pistachio nut shells, dried grapes, and papaya, and quantitative on poultry bones. There was no difficulty in identifying irradiated meat bones, dried grapes, and papaya. In the case of fish bones there is a need for further kinetic study on different species. Identification of irradiation in pistachio nuts is more complicated and additional research is needed before further trials. All laboratories were able to distinguish between chicken bones irradiated at 1 to 3 kGy or 7 to 10 kGy although there was a partial overlap between the results.     

Enterobacter sakazakii survives spray drying

Four strains of Enterobacter sakazakii were inoculated into 35% reconstituted skim milk at 10⁷ and 10² cfu/g dry wt. After spray-drying in a Buchi mini spray drier (inlet 160°C and outlet 90°C), the resulting powders were analysed for E. sakazakii by enrichment and enumeration. In all cases, E. sakazakii survived the spray drying process and were detected in the powders with a low inoculum and enumerated in all the powders with the high inoculum for at least 12 weeks. The results emphasize that the controls in place to prevent E. sakazakii from getting to the spray drier are essential.     

Colour Removal in a Reservoir and the Dredging and Dewatering of the Deposited Waterworks Sludge

T he A lbert R eservoir of the Yorkshire Water Authority was built in the 1850s as the final raw water storage in the chain of impounding and storage reservoirs which feed Halifax, Brighouse, and Elland in West Yorkshire (Fig. 1).
This paper describes the problems encountered with increasing raw water colour since the mid1970s, the action taken to pretreat the water at the Albert reservoir prior to pressure filtration at the Thrum Hall Water Treatment Works (WTW), and the resulting problems with the deposited alum sludge in Albert reservoir.     

MODEL REFERENCE ADAPTIVE CONTROL BASED ON LIAPUNOV'S DIRECT METHOD Part II: Hybrid Computer Simulation and Experimental Application

A Model Reference Adaptive Control (MRAC) system is evaluated via hybrid computer simulation and experimental application to a computer-controlled, pilot plant evaporator. In both the simulation and experimental studies, the MRAC system performed well and was insensitive to unmeasured process disturbances, to the choice of the initial control policy and to changes in plant operating conditions. In addition to providing an algorithm for adapting control systems to accommodate changing process parameters, MRAC also provides a systematic approach for tuning or developing multivariable control systems for time-invariant processes.     

Electronic Conductivity, Seebeck Coefficient, and Defect Structure of LaFeO3

Electronic conductivity and Seebeck coefficients of LaFeO₃ were measured as a function of temperature (1000° to 1400°C) and P ( O ₂) (10⁵ to 10⁻¹³ Pa). Electronic conduction was found to be n-type in the lower P ( O₂ ) range, and p -type in a higher P(O₂) range. The calculated carrier mobilities suggest a hopping-type conduction mechanism. The carrier concentrations were calculated as a function of P ( O₂ ) and the defect structure was described. It was found that the electrical properties of LaFeO₃ are determined not only by the concentration of oxygen vacancies, but also by the La/Fe ratio.     

MODEL REFERENCE ADAPTIVE CONTROL BASED ON LIAPUNOV'S DIRECT METHOD Part I: Theory and Control System Design†

The Liapunov design approach for model reference adaptive control (MRAC) is extended to include adaptive integral and setpoint control modes. The feasibility of the Liapunov approach is illustrated by designing a multi-variable MRAC system based on a fifth-order state space model of a pilot scale, double-effect evaporator. Simulation results are presented to demonstrate that the MRAC approach gives satisfactory control for a wide range of adaptive loop gains and despite very poor initial control policies.     

Time-resolved fluorescence microscopy of gunshot residue: an application to forensic science

Time‐resolved fluorescence microscopy has rapidly emerged as the technique of choice for many researchers aiming to gain specific insights into the dynamics of intricate biological systems. Although the unique advantages the technique provides over other methods have proven to be particularly useful in the biosciences, to date they have been largely unexploited by other research disciplines. In this paper, we demonstrate the capacity of time‐resolved fluorescence microscopy as a practical analytical tool in the forensic sciences via the imaging of gunshot residues that are expelled when a firearm is discharged. This information may prove to be useful for determination of the true sequence of events that took place in a firearm related crime.     

Phase Separation in the System (Fe,Mn)O

Transmission electron microscopy was used to observe variations in composition in single crystals of Fe _y Mn_{1– y} O_{1+] x} on a scale of 100 to 500 Å. Compositional fluctuations were resolved as lamellar-like striations oriented primarily in the [100] direction. Specimens had been equilibrated at 900°C in oxygen partial pressures within the monoxide phase region and then quenched to room temperature. A region of solid-solid immiscibility in the monoxide phase field is proposed. A different submicrostructure resulted from low-temperature decomposition (150°C) due to localized heating when samples were prepared by ion-bombardment thinning.