Experimental Investigation of Nucleate Boiling on a Thermal Capacitive Heater Under Variable Gravity Conditions

In the present work the behavior of single vapor bubbles of FC-72, generated on a thermal capacitive heater element, has been investigated during microgravity. A newly developed heater design allows temperature measurements by highspeed infrared thermography on the backside of the heater surface at a distance of approx. 800 nm from the fluid/heater-interface. The employed heater was manufactured by Physical Vapor Deposition (PVD) of a chromium based layer for better emissivity (Slomski et al., Mater Sci Technol 41:161?C165, 2010) and a pure chromium heating layer supplying the energy required for bubble generation and sustainment by electrical heating. The thermal diffusivity of the employed Calcium Flouride (CaF) heater substrate is comparable to the thermal diffusivity of stainless steel, which makes this heater design very close to technical applications. The acquired transient temperature fields of the heater surface allow numerical determination of the local heat flux from the heater surface to the fluid. A local temperature drop and high heat fluxes have been observed in the vicinity of the 3-phase contact line. This effect has already been reported by former publications for thin stainless steel foil heaters (Stephan and Hammer, Int J Heat Mass Transfer 30:119?C125, 1994; Wagner et al., Int J Heat Mass Transfer 42:875?C883, 2006) and is also confirmed for heaters with significantly higher thermal capacities.     

Fumonisin B1, fumonisin B2, zearalenone and ochratoxin A contamination of maize in Croatia

Mycotoxins are products of moulds that frequently contaminate maize. In this study the presence of mycotoxins fumonisin B₁ (FB₁), fumonisin B₂ (FB₂), zearalenone (ZEA) and ochratoxin A (OTA) was determined in 49 maize grain samples collected in autumn 2002. The most frequent finding was that of FB₁(100%), followed by ZEA (84%) and OTA (39%), while FB₂ was found only in three samples. The co-occurrence of two and three mycotoxins was found in 55 and 37% of samples, respectively. The concentrations (mean ± SD) of FB₁, ZEA and OTA in positive samples were 459.8 ± 310.7, 3.84 ± 6.68 and 1.47 ± 0.38 µg kg^-1, respectively, and the concentrations of FB₂ in three positive samples were 68.4, 109.2 and 3084.0 µg kg^-1. Although such low concentrations of mycotoxins are not a significant source of exposure in countries with a European diet, a few samples with extreme values indicate that thorough control is needed.     

Oxidation Resistance of Cast Magnesium Alloys

The purpose of the present study was to examine the oxidation of Mg–Al alloys in the atmosphere of oxygen at various temperatures. The basic examination methods used were differential scanning calorimetry (DSC) and thermogravimetry (TG). The results show that the oxide layer can either protect the material against progressive oxidation or it can cause complete disintegration of material. The nature of the oxide layer formed depends on the external conditions, i.e. on the atmosphere, temperature, and type of alloy. A model of the Mg–Al alloy oxidation was calculated from the TG curves.     

Effect of Agronomical Factors and Storage Conditions on the Tocopherol Content of Oblica and Leccino Virgin Olive Oils

The influence of agronomical factors (two growing areas and four harvest periods) and storage conditions of virgin olive oils (room temperature, +4 and ?20 °C) on tocopherols was investigated on two cultivars having significantly different tocopherol content (Oblica 269–443 mg/kg, Leccino 403–784 mg/kg). α‐Tocopherol accounted for 97 % of total tocopherols and its content decreased during ripening of both cultivars. In a warmer growing area both cultivars gained a higher γ‐tocopherol content while only Leccino showed a higher content of α‐tocopherol. After 12 months of storage α‐tocopherol content decreased by up to 27 %. Lower storage temperatures did not always contribute to the higher stability of α‐tocopherol compared to room temperature.     

Molecular Mechanics Study of Nickel(II) Octaethylporphyrin Adsorbed on Graphite(0001)

The effects of adsorption on the graphite(0001) surface on the nonplanar distortions of nickel(II)octaethylporphyrin were studied by molecular mechanics (MM) approach. Using the Consistent Force Field (CFF) program with previously developed parameters for metalloporphyrins and supplemented to treat intermolecular interactions geometry optimizations were carried out for 43 conformations of 28 distinct conformers of nickel(II)octaethylporphyrin. The stable energy-minimized conformers were stereochemically characterized, analyzed by the Normal-coordinate Structural Decomposition (NSD) method and compared with the available theoretical and experimental data for the isolated nickel(II)octaethylporphyrin structures.     

Mediated and direct effects of general control beliefs on obsessive compulsive symptoms.

Although control-related cognitions have often been implicated in discussions of obsessive compulsive disorder (OCD), empirical investigations of the relationship between control constructs and OCD symptoms have been relatively limited. This article investigated the hypothesis that OCD symptoms may be linked with a higher desire for control (DC), but a lower sense of control (SC) over the self and environment, leading to motivation for compulsive symptoms. It also investigated whether this effect was direct, or mediated through other OCD-related cognitions. This hypothesis was investigated in a nonclinical population, using path analyses controlling for depression. It was found that higher levels of DC and lower levels of SC were associated with higher levels of OCD-related beliefs, and with symptoms via higher OCD-related beliefs. SC was also directly linked with higher OCD symptoms. Control beliefs regarding both the internal (emotions) and external (threat) environment were related to OCD symptoms. Implications for therapy and research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parents' child-rearing style and child's sociometric status.

Examined relationships between parents' childrearing style, the child's prosocial behavior, and the child's sociometric status. The sample consisted of 112 children (6–11 yrs of age) and both their parents. Parental behavior in the interaction with the child was observed at home when parents and child worked together in 2 structured tasks. Factor analyses of parental behavior revealed that 2 factors, Authoritative/Democratic and Authoritarian/Restrictive, can be found in the subsamples of mothers and fathers. These 2 dimensions of maternal and paternal behavior appeared to be predictive of both the child's prosocial behavior and sociometric status. Results are discussed in terms of the possible link between parent and peer systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychoneuroendocrine effects of resource-activating stress management training.

Objective: The stress-induced release of cortisol has been linked to detrimental health outcomes. Therefore, strategies to attenuate cortisol stress responses are of interest for prevention and treatment of stress-related symptoms and problems. Previous studies have found protective effects of cognitive-behavioral stress management training--which focuses on the modification of stress-inducing cognitions--on cortisol stress responses; however, the effects of resource-oriented interventions on cortisol stress responses are unknown. Design: The longitudinal effects of resource-oriented stress management training (Zurich resource model training) on cortisol stress responses and cognitive appraisal of a standardized psychosocial stress test were evaluated in 54 healthy male participants assigned randomly to treatment and control groups. The Trier Social Stress Test (TSST; C. Kirschbaum, Wust, & Strasburger, 1992) was administered to all participants 3 months after the treatment group underwent stress management training. Main Outcome Measures: Saliva cortisol samples were taken before, during, and after the TSST, and cognitive stress appraisal was assessed before the test. Results: The treatment group had significantly attenuated cortisol responses and stress appraisals in comparison to the control group. The endocrine differences were mediated by differences in cognitive appraisals. Discussion: These results indicate that resource-oriented stress management training effectively reduces endocrine stress responses to stress in healthy adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)