Non-Classical Electrostriction in Hydrated Acceptor Doped BaZrO3: Proton Trapping and Dopant Size Effect

Point defects such as oxygen vacancies and protonic interstitials are not only essential for ionic conductivity in oxides since they also affect the mechanical and electromechanical properties. These properties of nominally dry and hydrated proton-conducting BaZr_0.85M_0.15O_2.925+δH_2δ (M = Al, Ga, Sc, In, Y, Eu) ceramics are investigated. Doping decreases Young's modulus with increasing ionic radii difference between the dopant and the host. Nominally dry samples show consistently higher Young's moduli than hydrated samples. All samples exhibit large non-classical electrostriction, with a negative electrostriction coefficient M₃₃<0. M₃₃ shows saturation with the field and a non-ideal Debye relaxation with frequency. The low-frequency M₃₃ value for both dry and hydrated samples shows a similar dependence on dopant radius as Young's modulus. For the hydrated samples, the relaxation frequency increases by a factor >100 in the series Ga-Y, emphasizing the importance of proton trapping, with Y-doped samples having minimal trapping energy. This coincides with the fact that the saturation strain for Y-doped samples is also the smallest. In light of these findings, it is concluded that the present data give strong evidence for the existence of defect-related elastic dipoles in acceptor doped barium zirconate and that the non-classical electrostriction originates in their reorientation under electric field.     

Dietary Salt Accelerates Orthodontic Tooth Movement by Increased Osteoclast Activity

Dietary salt uptake and inflammation promote sodium accumulation in tissues, thereby modulating cells like macrophages and fibroblasts. Previous studies showed salt effects on periodontal ligament fibroblasts and on bone metabolism by expression of nuclear factor of activated T-cells-5 (NFAT-5). Here, we investigated the impact of salt and NFAT-5 on osteoclast activity and orthodontic tooth movement (OTM). After treatment of osteoclasts without (NS) or with additional salt (HS), we analyzed gene expression and the release of tartrate-resistant acid phosphatase and calcium phosphate resorption. We kept wild-type mice and mice lacking NFAT-5 in myeloid cells either on a low, normal or high salt diet and inserted an elastic band between the first and second molar to induce OTM. We analyzed the expression of genes involved in bone metabolism, periodontal bone loss, OTM and bone density. Osteoclast activity was increased upon HS treatment. HS promoted periodontal bone loss and OTM and was associated with reduced bone density. Deletion of NFAT-5 led to increased osteoclast activity with NS, whereas we detected impaired OTM in mice. Dietary salt uptake seems to accelerate OTM and induce periodontal bone loss due to reduced bone density, which may be attributed to enhanced osteoclast activity. NFAT-5 influences this reaction to HS, as we detected impaired OTM and osteoclast activity upon deletion.     

Analysis of the survival of <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> in food-grade lubricants

Listeria monocytogenes is a ubiquitously occurring Gram-positive bacterium, which is associated with raw ready-to-eat foods, in particular with smoked or graved salmon. Due to its tenacity and psychrotrophic growth properties, it may persist on the equipment and machinery used in food production. In this study, we analysed the survival of three L. monocytogenes strains in eight H1 lubricants, seven greases and one oil, applicable for food-processing machinery. None of the native lubricants contained Listeria spp. above the detection limit of 10³ cfu/g. In artificially contaminated lubricants, the viable counts of different L. monocytogenes strains decreased by more than 99.9% within 7 days, and the reduction rates were found to dependent on the composition of the respective lubricant as well as on the L. monocytogenes strain. Chemical binding of either benzoate or acetate to native grease 3 caused a similar anti-listerial activity, but a decreased effect was observed when stearic acid was used. When benzoate, acetate, salicylate or parabene was added at a concentration of 0.5% to native grease 1, similar anti-listerial effects were observed. The water content (0, 1 and 5%) and the age of the lubricant did not influence the results. Used lubricants originating from dismantled industrial machinery did not contain L. monocytogenes, though this microorganism was re-isolated from the lubricants following artificial contamination. Thus, there is no evidence that L. monocytogenes replicate or persist in the H1 lubricants used in this study.     

Application of Two-Color LIF Thermometry to Nucleate Boiling

The laser-induced fluorescence （LIF） thermometry is applied to measure the temperature field surrounding a single vapor bubble growing at an artificial nucleation site. In order to correct measurement errors due to the non-uniformity of the incident laser intensity, the two-color LIF thermometry technique is used in this nucleate boiling experiment. This technique is based on the use of two fluorescent dyes： the temperature sensitive dye Rhodamine B and the temperature insensitive dye Sulforhodamine-lO1. The concentration of the dyes is optimized by analyzing the behavior of fluorescence intensities. The mapping between the two images is determined through a geometrical calibration procedure. This technique presents a success in correcting the non uniformities due to the reflection of the light at the bubble surface and to the temperature gradient. The obtained temperature fields show that the two-color LIF is a promising technique in the investigation of nucleate boiling.     

Impact of geothermal well testing on exposed vegetation in the Northern Negros Geothermal Project, Philippines

The impact of geothermal fluid discharges during the testing of Pataan 5-D well was evaluated on seedlings of mahogany (Swietenia macrophylla King) at various distances from the well and on natural forest vegetation around the wellpad. The parameters measured were: (1) geothermal brine spray concentration; (2) plant concentration of geothermal signature ions (B, Cl, Li and Na); (3) symptoms of plant damage; and (4) plant recovery. Meteorological parameters were also gathered. Adverse effects on the test plants were observed at distances of 5–50 m from the well silencer for over-spray during the horizontal discharge and at 50–350 m from the wellhead during the vertical discharge. Salinity was identified as a significant cause of plant damage. Observed symptoms of damage included drying of leaf tissues expressed as necrotic areas, which occurred first at the tip of older leaves and progressed along the margins as severity increased, resulting in abnormal defoliation. Recovery of seedlings and natural vegetation from sprays was observed in both vertical and horizontal discharges.     

An ultra-low power successive approximation A/D converter with time–domain comparator

This paper presents an ultra-low power successive approximation analog-to-digital converter. An improved implementation of the binary weighted capacitors array and a novel comparator that operates in the time instead of the voltage domain are effective and power efficient. The circuit, fabricated in a conventional 0.18-μm CMOS technology, achieves a sampling rate of 100 kS/s and an effective number of bit of 9.4. Using a 1-V supply voltage, the achieved power consumption is 3.8 μW, leading to a Figure of Merit as low as 56 fJ/conversion-level.     

International Migration for Work-Consequences for the Families Who Remain at Home (The Case of Romania)

This paper analyses the consequences of international migration for work on families who remain at home in a Romanian rural sample. Five types of effects were identified: financial; on spousal relations; on children; on old family members and on composition of the population. The most important are the financial impacts, but there are also invisible side-effects, such as deterioration in the relations between spouses and the decrease of the parents?? roles for children. The importance of the old family members is re-evaluated; they are key social links between migrants and the family members that have remained at home.