Positron annihilation and nano-indentation analysis of irradiation effects on the microstructure and hardening of A508-3 steels used in Chinese HTGR

The irradiation and annealing behavior of Chinese A508-3 reactor pressure vessel (RPV) steel (0.04 wt% Cu) after 3 MeV Fe-ion irradiation ranging from 0.1 to 20 dpa at room temperature (called RTRPV) and high temperature (250?°C, called HTRPV) was studied by positron annihilation Doppler broadening (PADB) spectroscopy and nano-indentation hardness. PADB showed that the density of vacancy-type defects was higher for low-temperature irradiations. The higher hardness was found after high-temperature irradiation because of the formation of solute clusters during irradiation. Positron annihilation measurements revealed the interaction and clustering of vacancies with solute clusters which were introduced by Fe-ion irradiation. For both RTRPVs and HTRPVs, the positron defect parameter and positron diffusion length showed the recovery of the irradiation-induced defects. Total recovery was observed after annealing at 450 °C.     

Intrinsic instability of flame–acoustic coupling

This paper shows that a flame can be an intrinsically unstable acoustic element. The finding is clarified in the framework of an acoustic network model, where the flame is described by an acoustic scattering matrix. The instability of the flame acoustic coupling is shown to become dominating in the limit of no acoustic reflections. This is in contrast to classical standing-wave thermoacoustic modes, which originate from the positive feedback loop between system acoustics and the flame. These findings imply that the effectiveness of passive thermoacoustic damping devices is limited by the intrinsic stability properties of the flame.     

Dynamic forecasting of individual cow milk yield in automatic milking systems

Accurate forecasting of dairy cow milk yield is useful to dairy farmers, both in relation to financial planning and for detection of deviating yield patterns, which can be an indicator of mastitis and other diseases. In this study we developed a dynamic linear model (DLM) designed to forecast milk yields of individual cows per milking, as they are milked in milking robots. The DLM implements a Wood's function to account for the expected total daily milk yield. It further implements a second-degree polynomial function to account for the effect of the time intervals between milkings on the proportion of the expected total daily milk yield. By combining these 2 functions in a dynamic framework, the DLM was able to continuously forecast the amount of milk to be produced in a given milking. Data from 169,774 milkings on 5 different farms in 2 different countries were used in this study. A separate farm-specific implementation of the DLM was made for each of the 5 farms. To determine which factors would influence the forecast accuracy, the standardized forecast errors of the DLM were described with a linear mixed effects model (lme). This lme included lactation stage (early, middle, or late), somatic cell count (SCC) level (nonelevated or elevated), and whether or not the proper farm-specific version of the DLM was used. The standardized forecast errors of the DLM were only affected by SCC level and interactions between SCC level and lactation stage. Therefore, we concluded that the implementation of Wood's function combined with a second-degree polynomial is useful for dynamic modeling of milk yield in milking robots, and that this model has potential to be used as part of a mastitis detection system.     

Towards impedance-based temperature estimation for Li-ion battery packs

In order to meet the required power and energy demand of battery-powered applications, battery packs are constructed from a multitude of battery cells. For safety and control purposes, an accurate estimate of the temperature of each battery cell is of vital importance. Using electrochemical impedance spectroscopy (EIS), the battery temperature can be inferred from the impedance. However, performing EIS measurements simultaneously at the same frequency on each cell in a battery pack introduces crosstalk interference in surrounding cells, which may cause EIS measurements in battery packs to be inaccurate. Also, currents flowing through the pack interfere with impedance measurements on the cell level. In this paper, we propose, analyse, and validate a method for estimating the battery temperature in a battery pack in the presence of these disturbances. First, we extend an existing and effective estimation framework for impedance-based temperature estimation towards estimating the temperature of each cell in a pack in the presence of crosstalk and (dis)charge currents. Second, the proposed method is analysed and validated on a two-cell battery pack, which is the first step towards development of this method for a full-size battery pack. Monte Carlo simulations are used to find suitable measurement settings that yield small estimation errors and it is demonstrated experimentally that, over a range of temperatures, the method yields an accuracy of ±1°C in terms of bias, in the presence of both disturbances.     

Study of a new energy efficient process for French fries production

A new, energy efficient production process for French fries was developed and evaluated. Superheated steam (SHS) was used for evaporation of water instead of pre-drying with air and par-frying with oil. The product was frozen by vacuum cooling. Unfortunately, with this process it was not possible to reach the quality of conventional French fries. Sensory analysis indicated that the main quality defect was a tough crust with a fatty appearance. Confocal Scanning Laser Microscopy showed that this was caused by skin formation on the surface during both SHS drying and vacuum cooling. A frying step was necessary to obtain a porous crust. A satisfactory product quality was feasible after drying with SHS instead of air. Due to the concessions made for the product quality, the final energy reduction was limited. Nevertheless, this study has gained more insight into how processing affects potato tissue on micro-scale and it has shown that a porous structure is essential for good quality French fries.     

Fate of ivermectin residues in ewes' milk and derived products

The fate of ivermectin (IVM) residues was studied throughout the processing of daily bulk milk from 30 ewes (taken up to 33 d following subcutaneous administration of 0.2 mg IVM/kg b.w.) in the following milk products: yoghurt made from raw and pasteurized milk; cheese after pressing; 30- and 60-day ripened cheese; and whey, secondary whey and whey proteins obtained after cheese-making (albumin cheese). The concentration of the H2B1a component of IVM was analysed in these dairy products using an HPLC method with fluorescence detection. The mean recovery of the method was, depending on the matrix, between 87 and 100%. Limits of detection in the order of only 0.1 microg H2B1a/kg of product were achieved. Maximum concentrations of IVM were detected mostly at 2 d after drug administration to the ewes. The highest concentration of IVM was found on day 2 in 60-day ripened cheese (96 microg H2B1a/kg cheese). Secondary whey was the matrix with the lowest concentration of IVM (<0.6 microg H2B1a/ kg). Residue levels fell below the limits of detection between day 5 (for secondary whey) and day 25 (for all cheese samples). In the matrices investigated, linear correlations between daily concentrations of IVM, milk fat and solid content were evident. During yoghurt production, fermentation and thermal stability of IVM was observed. During cheese production, approximately 35% of the IVM, present in the raw (bulk) milk samples, was lost. From the results it was concluded that the processing of ewes' milk did not eliminate the drug residues under investigation. The consequences of IVM in the human diet were discussed. Milk from treated animals should be excluded from production of fat products like cheese for longer after treatment with IVM than for lower fat products.     

Secondary Traumatization in Partners and Parents of Dutch Peacekeeping Soldiers.

This study examines secondary traumatization among 708 partners and 332 parents of Dutch peacekeepers (i.e., personnel who participated in military actions implemented by international organizations such as the United Nations). Partners or parents of peacekeepers with 4 levels of posttraumatic stress symptoms were compared on posttraumatic stress, health problems, the quality of the marital relationship, and social support. In comparison with partners of peacekeepers without posttraumatic stress disorder (PTSD) symptoms, partners of peacekeepers with PTSD symptoms reported more sleeping and somatic problems, reported more negative social support, and judged the marital relationship as less favorable. No significant differences were found for parents. Thus, peacekeepers' stress reactions were related to various problems of their partners. A systemic approach to the treatment of persons with PTSD appears appropriate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

THE RELATION BETWEEN BIOMARKERS AND OCCUPATIONAL EXPOSURE TO POLYCYCLIC AROMATIC COMPOUNDS

Recently a paper was published in which we reviewed a number of studies involving occupational surveys, where both the external polycyclic aromatic hydrocarbon (PAH) exposures and one or more biomarkers were quantitatively monitored. As part of that review a statistical analysis of the results of these studies was performed, which revealed that only urinary 1-hydroxypyrene (1OHPy) and possibly chromosome aberrations (CA) showed a correlation with PAH exposure, while unexpectedly, DNA adducts did not. Another observation was that although in controlled laboratory experiments good correlations have been found to occur between DNA adducts and exposure doses to polycyclic aromatic compounds (PACs), such a correlation was not found in the human occupational exposure studies reviewed. Also the analyses showed that sister chromatid exchanges (SCE) and micronuclei (MN) exhibited a very weak or an absence of a correlation, respectively, with external PAH exposure. The subject of this article is an attempt to explain: (a) why the levels of only some biomarkers correlate with PAH exposures and (b) the differences in results between controlled animal experiments and human monitoring studies.     

Effect of temperature on recrystallization behavior of cocoa butter

Crystallization of cocoa butter in the β phase directly from the melt is only possible by employing the memory effect of cocoa butter. Cocoa butter crystallized in the β phase, heated to the so-called maximal temperature (just above its melting end point), recrystallizes in the β phase after cooling to a crystallization temperature. The influence of the maximal and crystallization temperatures on the recrystallization behavior has been investigated for two cocoa butters. Rapid-starting recrystallization into the β(VI) phase and slow-starting recrystallization into the β(V) have been observed. It is concluded that rapid-starting recrystallization is induced by high-melting 1,3-distearoyl-2-oleoyl-glycerol (SOS)-rich crystals. The two β phases were identified by X-ray powder diffraction and melting ranges. However, the X-ray powder diffraction patterns for the β phases depended on the composition of the cocoa butter and on the crystallization method used. Therefore, it was not possible to take any particular β(VI) X-ray powder diffraction pattern as a standard for the β(VI) phase of all cocoa butters.