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The article discusses the winter activity of reptile species in Montenegro, highlighting the impact of hibernation on their survival and development. It mentions the observation of six reptile species, including lizards and turtles, during the winter period of 2023/2024 in various towns. The study suggests that global warming and climate change are influencing reptiles' winter activity, with higher temperatures potentially leading to increased winter activity. The findings contribute to understanding the biology of these species and emphasize the need for further research on the effects of climate change on reptiles. [Extracted from the article]

The article presents the meteorological characteristics of each month of the year in Spain, based on popular sayings. The author, José María Lorente, was an expert in meteorology and published several books on the subject. The article highlights the characteristics of the climate in January, February, March, April, and May, including information on temperatures, rainfall, and specific weather phenomena for each month. It emphasizes that the mentioned characteristics are usually observed in normal years. [Extracted from the article]

The rate constants for the NCN+NO reaction have been measured by laser photolysis/laser-induced fluorescence technique in the temperature range of 254–353 K in the presence of He (40–600 Torr) and N2 (30–528 Torr) buffer gases. The NCN radical was produced from the photodissociation of NCN3 at 193 nm and monitored with a dye laser at 329.01 nm. The reaction was found to be strongly positive-pressure dependent with negative-temperature dependence, as was reported previously. The experimental data could be reasonably accounted for by dual-channel Rice–Ramsperger–Kassel–Marcus calculations based on the predicted potential-energy surface using the modified Gaussian-2 method. The reaction is predicted to occur via weak intermediates, cis- and trans-NCNNO, in the 2A″ state which crosses with the 2A′ state containing more stable cis- and trans-NCNNO isomers. The high barriers for the fragmentation of these isomers and their trapping in the 2A′ state by collisional stabilization give rise to the observed positive-pressure dependence and negative-temperature effect. The predicted energy barrier for the fragmentation of the cis-NCNNO (2A′) to CN+N2O also allows us to quantitatively account for the rate constant previously measured for the reverse process CN+N2O→NCN+NO. [ABSTRACT FROM AUTHOR]

Extreme temperature anomalies such as heat and cold waves may have strong impacts on human activities and health. The heat waves in Western Europe in 2003 and in Russia in 2010, or the cold wave in South-Eastern Europe in 2012, generated a considerable amount of economic loss and resulted in the death of several thousands of people. Providing an operational system to monitor extreme temperature anomalies in Europe is thus of prime importance to help decision makers and emergency services which are responsive to an unfolding extreme event. In this study, the development and the validation of a monitoring system of extreme temperature anomalies are presented. The first part of the study describes the methodology based on the persistence of events exceeding a percentile threshold. The method is applied to three different observational datasets, in order to assess the robustness and highlighting uncertainties in the observations. The climatology of extreme events from the last 21 years is then analysed to highlight the spatial and temporal variability of the hazard and discrepancies amongst the observational datasets are discussed. In the last part of the study, the products derived from this study are presented and discussed regarding previous studies. The results highlight the accuracy of the developed index and the statistical robustness of the distribution used to calculate the return periods. [ABSTRACT FROM AUTHOR]

Understanding how weather impacts health is critical, especially under a changing climate; however, relatively few studies have investigated subtropical regions. We examined how mortality in São Paulo, Brazil, is affected by cold, heat, and heat waves over 14.5 years (1996-2010). We used over-dispersed generalized linear modeling to estimate heat- and cold-related mortality, and Bayesian hierarchical modeling to estimate overall effects and modification by heat wave characteristics (intensity, duration, and timing in season). Stratified analyses were performed by cause of death and individual characteristics (sex, age, education, marital status, and place of death). Cold effects on mortality appeared higher than heat effects in this subtropical city with moderate climatic conditions. Heat was associated with respiratory mortality and cold with cardiovascular mortality. Risk of total mortality was 6.1 % (95 % confidence interval 4.7, 7.6 %) higher at the 99th percentile of temperature than the 90th percentile (heat effect) and 8.6 % (6.2, 11.1 %) higher at the 1st compared to the 10th percentile (cold effect). Risks were higher for females and those with no education for heat effect, and males for cold effect. Older persons, widows, and non-hospital deaths had higher mortality risks for heat and cold. Mortality during heat waves was higher than on non-heat wave days for total, cardiovascular, and respiratory mortality. Our findings indicate that mortality in São Paulo is associated with both cold and heat and that some subpopulations are more vulnerable. [ABSTRACT FROM AUTHOR]

Background: Over the past two decades, major epidemics of hand, foot, and mouth disease (HFMD) have occurred throughout most of the West-Pacific Region countries, causing thousands of deaths among children. However, few studies have examined potential determinants of the incidence of HFMD. Methods: Reported HFMD cases from 2912 counties in China were obtained for May 2008. The monthly HFMD cumulative incidence was calculated for children aged 9 years and younger. Child population density (CPD) and six climate factors (average-temperature [AT], average-minimum-temperature [ATmin], average-maximum-temperature [ATmax], averagetemperature- difference [ATdiff], average-relative-humidity [ARH], and monthly precipitation [MP]) were selected as potential explanatory variables for the study. Geographically weighted regression (GWR) models were used to explore the associations between the selected factors and HFMD incidence at county level. Results: There were 176,111 HFMD cases reported in the studied counties. The adjusted monthly cumulative incidence by county ranged from 0.26 cases per 100,000 children to 2549.00 per 100,000 children. For local univariate GWR models, the percentage of counties with statistical significance (p<0.05) between HFMD incidence and each of the seven factors were: CPD 84.3%, ATmax 54.9%, AT 57.8%, ATmin 61.2%, ARH 54.4%, MP 50.3%, and ATdiff 51.6%. The R2 for the seven factors' univariate GWR models are CPD 0.56, ATmax 0.53, AT 0.52, MP 0.51, ATmin 0.52, ARH 0.51, and ATdiff 0.51, respectively. CPD, MP, AT, ARH and ATdiff were further included in the multivariate GWR model, with R2 0.62, and all counties show statistically significant relationship. Conclusion: Child population density and climate factors are potential determinants of the HFMD incidence in most areas in China. The strength and direction of association between these factors and the incidence of HFDM is spatially heterogeneous at the local geographic level, and child population density has a greater influence on the incidence of HFMD than the climate factors. [ABSTRACT FROM AUTHOR]

Abstract: Extreme cold and heat waves, characterized by a number of cold or hot days in succession, place a strain on people''s cardiovascular and respiratory systems. The increase in deaths due to these waves may be greater than that predicted by extreme temperatures alone. We examined cold and heat waves in 99 US cities for 14 years (1987–2000) and investigated how the risk of death depended on the temperature threshold used to define a wave, and a wave''s timing, duration and intensity. We defined cold and heat waves using temperatures above and below cold and heat thresholds for two or more days. We tried five cold thresholds using the first to fifth percentiles of temperature, and five heat thresholds using the 95–99 percentiles. The extra wave effects were estimated using a two-stage model to ensure that their effects were estimated after removing the general effects of temperature. The increases in deaths associated with cold waves were generally small and not statistically significant, and there was even evidence of a decreased risk during the coldest waves. Heat waves generally increased the risk of death, particularly for the hottest heat threshold. Cold waves of a colder intensity or longer duration were not more dangerous. Cold waves earlier in the cool season were more dangerous, as were heat waves earlier in the warm season. In general there was no increased risk of death during cold waves above the known increased risk associated with cold temperatures. Cold or heat waves earlier in the cool or warm season may be more dangerous because of a build up in the susceptible pool or a lack of preparedness for extreme temperatures. [Copyright &y& Elsevier]

Abstract: Introduction: As is known, the effects of extreme temperatures on mortality are characterised by an annual periodicity, with a rise centred in the winter months. The most recent epidemiological studies show that mortality caused by cold waves is, in many cases, comparable to that caused by the severest heat waves. This study sought to quantify the rise in mortality due to extreme cold and the factors that determine the relationship between these variables in Castile-La Mancha (Spain). Methods: We examined the effect of extreme winter temperature on daily non accidental cause mortality in Castile — La Mancha from 1975 to 2003, for all ages. Quantitative analyses were performed using ARIMA models, with other covariates, such as influenza, pressure trends, relative humidity, and cold wave duration and chronological number. Results: There were two mortality peaks: a short-term peak (with a lag of 3 to 7 days); and a longer term peak (of under two weeks). Excess mortality during cold waves was around 10% per degree centigrade below the threshold temperature for all the provinces except Guadalajara, where an increase of only 4.61% was detected. Mortality increased in response to rises in cold-wave duration and relative humidity. Cold waves occurring at the end of the “winter” season caused the greatest mortality. Conclusions: This study confirms that daily mortality in Castile — La Mancha increases during cold waves. Efficient cold-wave prevention plans must therefore be implemented. Such plans should be based on in-depth knowledge of the causes that underlie and modulate the relationship between low temperatures and health effects. [ABSTRACT FROM AUTHOR]

Cold waves commonly occur in higher latitudes under prevailing high pressure systems especially during winter season which cause serious economical loss and cold related death. Accurate prediction of such severe weather events is important for decision making by administrators and for mitigation planning. An Advanced high resolution Weather Research and Forecasting mesoscale model is used to simulate a severe cold wave event occurred during January 2006 over Europe. The model is integrated for 31 days starting from 00UTC of 1 January 2006 with 30 km horizontal resolution. Comparison of the model derived area averaged daily mean temperatures at 2m height from different zones over the central Europe with observations indicates that the model is able to simulate the occurrence of the cold wave with the observed time lag of 1 to 3 days but with lesser intensity. The temperature, winds, surface pressure and the geopential heights at 500 hPa reveal that the cold wave development associates with the southward progression of a high pressure system and cold air advection. The results have good agreement with the analysis fields indicates that the model has the ability to reproduce the time evolution of the cold wave event. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, ice slurry is produced by direct contact heat transfer between water and a coolant, Fluroinert FC 84. An analytical model has been developed to predict the growth of ice around the injected supercooled coolant droplets, which involves phase change and heat transfer between layers. During the journey of the coolant droplets through the ice generator, detachment of ice layer formed on the droplets occurs. Equations have been development to describe the process of detachment. Experiments were performed to validate the model developed to predict the ice generation. Parametric studies were then carried out on ice growth rate for different variables, such as droplet diameters and initial liquid temperatures. Both droplet diameters and initial liquid temperatures play an important role in the ice formation around the supercooled liquid surface. Ice growth rate increases with the increase of the droplet diameter, while the growth rate decreases with the increase of the initial temperature of the liquid droplet. For an ice slurry system, it is found that the predicted values of ice slurry generation are in good agreement with the experimental findings. [Copyright &y& Elsevier]

Abstract: The 27Ω rhodium–iron ceramic sensor is suitable for the measurement of temperatures from 1.2 to 300K, and can be used up to 800K. The sensor has been available for over 30years, and around 12,000 units have been produced in this period. A new manufacturer of the rhodium–iron wire has resulted in different resistance–temperature behaviour with each wire batch. This has required a re-analysis of the calibration data. We discuss two types of calibration data: multi-point across the temperature range, and three-point at temperatures close to 4.2K, 77K, and 273K. In both types it is shown that a reference function is of help with the data analysis. We propose a method for improving the interpolation accuracy for a three-point calibration when using a reference function. [Copyright &y& Elsevier]

Abstract: To assess the potential of arabinoxylan (AX)-rich psyllium (Plantago ovata Forsk) seed husk (PSH) as a source for production of arabinoxylo-oligosaccharides (AXOS), the parameters determining PSH AX extraction yield and the chemical and enzymic hydrolysis of PSH AX were investigated. The seed husk material had a high content of AX (62.5%) with an arabinose to xylose ratio of 0.41. The water extractability of PSH AX was affected by suspension concentration rather than by temperature. Maximally, 27% of all AX could be extracted, even when using very dilute suspensions (0.1%w/v). When subjected to alkaline conditions, a pH of at least 12 was needed to significantly increase extractability (up to 77% of all AX). The extractability-increasing effect of alkali was, however, reversible, as extractability decreased again when lowering the pH. Acid hydrolysis at high temperature drastically increased AX extraction yields (up to 97% of all AX), released monomeric arabinose (up to 38%), and lowered the average degree of polymerisation (DPavg) of the AX (down to 31). The presence of substituents (arabinose, xylose, rhamnose and galacturonic acid) on the xylan backbone was an important factor limiting degradation by xylanases. Enzyme preparations containing substituent-removing enzymes were far better for enhancing the extractability of a large portion of the AX population (up to 82%) and for degrading the extracted fragments (down to DPavg 14) than preparations lacking such activities. The above results show that PSH is a good source for the production of AXOS, since both chemical and enzymic treatments significantly increase the extractability of PSH AX and convert PSH AX molecules into small fragments. [Copyright &y& Elsevier]

We have prepared conductometric NO2gas sensors based on single-wall carbon nanotube (SWNT) networks. The SWNT properties are modified systematically by varying the annealing temperature between 350 to 550 °C under vacuum. Thermal annealing is not only necessary to remove dispersant used for nanotube dispersion but also plays an important role in optimizing the gas sensing abilities. In this paper, the sensing performance is evaluated through three crucial sensing characteristics: sensitivity to NO2, humidity interfering effect, and sensor stability over repeated use, all examined at room temperature. The sensor annealed at 400 °C shows the highest NO2sensitivity because of the structural properties, i.e., high specific surface area and the molecular geometry of having all carbon atoms at the tube-surface. The sensor also shows negligible humidity interfering effect and high sensor stability, originating from the hydrophobicity and chemical stability of the material, respectively. In contrast, annealing temperatures higher than 400 °C lead to structural defects in SWNTs and thus lower the sensing performance. We experimentally confirm that these SWNT characteristics make SWNTs a suitable gas sensing material from a practical perspective. [ABSTRACT FROM AUTHOR]

The laboratory characterization of a novel, second-generation portable gas chromatograph (GC) prototype designed for trace-level determinations of complex mixtures of volatile organic compounds (VOC) is described. The instrument incorporates a small, multi-stage adsorbent preconcentrator/injector (PCI), two series-coupled separation columns with fast, independent temperature-programming capabilities and junction-point pressure/flow control, and a detector consisting of an array of microfabricated chemiresistor (CR) sensors coated with thiolate-monolayer-protected gold nanoparticle films. Response patterns from the CR array are used in conjunction with chromatographic retention times to identify eluting mixture components. Scrubbed ambient air is used as the carrier gas. Enhancements in design relative to a previously reported first-generation prototype instrument have led to significant reductions in limits of detection as well as improvements in resolution, reliability, flexibility, and convenience. Key features of the instrument are characterized, with an emphasis on the tradeoffs in sensor array performance associated with operation at different temperatures and flow rates. The separation of a preconcentrated mixture of 31 VOCs in < 7 minutes is demonstrated. Projected detection limits are in the ppt range for most compounds, assuming a 1 L sample volume. [ABSTRACT FROM AUTHOR]

Abstract  A system-level model with lumped parameters for a thermal flow sensor is presented. The model is built with 13 circuit cells consisting of thermal resistors and thermal capacitors in SPICE. The circuit cell originates from the heat conduction equation using the Finite Differential Method, including the 2-D thermal conduction cell, the convection cell, and the thermal capacity in the chip. Based on the thermal model of the flow sensor, the 2-D temperature distribution of the chip can be calculated with SPICE in both the constant power mode (CP) and constant temperature difference mode (CTD). As an example, the system level model of the thermal anemometer in the CTD mode was established in PSPICE. Wind tunnel test was carried out to verify the system model, and show a reasonable agreement with the simulation results, with an error less than 8%. [ABSTRACT FROM AUTHOR]

Abstract: The shrinkage mechanism of BaTiO3 powder compacts containing 10mol% BaGeO3, synthesized by a precursor route and a conventional mixed-oxide method, are described herein. The calcination of a barium titanium germanium 1,2-ethanediolato complex precursor – [Ba(HOC2H4OH)4][Ti0.9Ge0.1(OC2H4O)3] (1) – at 730°C leads to a nm-sized Ba(Ti0.9/Ge0.1)O3 powder (1a) (S BET =16.9m2 g−1) consisting of BaTiO3 and BaGeO3. Whereas the conventional mixed-oxide method yields a powder (2) with a specific surface area of S BET =2.0m2 g−1. Powder compacts of 1a start to shrink at 790°C and the shrinkage rate reaches a maximum at 908°C. Dense ceramic bodies can be obtained below the appearance of the liquid melt (1120°C), therefore the shrinkage of 1a can be described by a solid state sintering mechanism. Otherwise the beginning of the shrinkage of powder 2 is shifted to higher temperatures and the formation of the liquid melt is necessary to obtain dense ceramic bodies. Isothermal dilatometric investigations indicate that the initial stage of sintering is dominated by sliding processes. XRD investigations show that below a sintering temperature of 1200°C ceramic bodies of 1a consist of tetragonal BaTiO3 and hexagonal BaGeO3, whereas temperatures above 1200°C lead to ceramics containing orthorhombic BaGeO3, and a temperature of 1350°C causes the formation of a Ba2TiGe2O8 phase. The phase evolution of ceramic bodies of 2 is similar to 1a, however a Ba2GeO4 phase is observed below a temperature of 1100°C. [Copyright &y& Elsevier]

Abstract: Well-crystallized anatase thin films with controlled thickness of 0.4–0.8μm were deposited on conductive titanium substrates through hydrolysis of titanium tetrafluoride aqueous solution at a low temperature of 60°C for various durations. A comparative study was carried out on their abilities to assist photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of rhodamine B (RhB) in water. The efficiency of the anatase thin film to assist photodegradation of RhB improved significantly with an applied potential of 0.4V versus SCE, independence of the film thickness and the calcination temperature. The PC degradation rate increased linearly with increasing film thickness to ca. 0.54μm, which remained stable with further increasing film thickness. The PEC degradation rate increased dramatically with slightly increasing film thickness from 0.41 to 0.46μm, which then decreased with further increasing film thickness. After a subsequent calcination at 500°C, the PC degradation rate reached the optimum value because of the bargaining effect between the increasing crystallinity and increasing grain size with increasing calcination temperatures. The appearance of rutile phase after calcination at temperatures beyond 600°C due to the direct oxidation of the Ti substrate deteriorated additionally the photocatalytic activity. The optimum calcination temperature for the PEC degradation rate was 500–600°C due to the additional effect of increasing conductivity of the anatase film with the increasing calcination temperature. [Copyright &y& Elsevier]

Abstract: The gradual vitrification evolution of atom mixing and local atomic pairing structure of the binary Zr–Ti alloy and pure Zr during solid-state accumulative roll bonding (ARB) at room temperature is traced numerically by molecular dynamic simulation. It is found that icosahedra and more random clusters will gradually develop with increasing ARB cycles in the Zr–Ti alloy, forming amorphous atomic packing. Following the idea for Zr–Ti, the vitrification of pure Zr layers during ARB is simulated. The crystalline pure Zr can be vitrified in the simulation provided that the rolling speed is high enough and the rolling temperature is maintained at around 300K. [Copyright &y& Elsevier]

Abstract: A new type of one-step preparation technique for the calcium carbide-derived carbon (CaC2-CDC) was developed. In this study, CaC2-CDC was synthesized from CaC2 in a freshly prepared chlorine environment in the temperature range of 100–600°C. The structure and morphology of as-prepared CaC2-CDC were studied by X-ray diffraction, transmission electron microscopy and nitrogen sorption experiment. Analysis of X-ray diffraction and transmission electron microscopy showed that CaC2-CDC is an amorphous nanoporous material, and the structure depended on the synthesis temperature. The resultant carbon demonstrated narrow pore size distribution (PSD) and specific surface area (SSA) close to 800m2 g−1 (for nitrogen sorption) at a synthesized temperature of 100°C. Increasing the reaction temperature above 400°C resulted in a lower SSA of CaC2-CDC due to the beginning of graphitization tendency. The nanoporous structure and narrow PSD of CaC2-CDC indicated potential application as electrode materials in supercapacitor. The CaC2-CDC exhibited a specific capacitance of 127.7Fg−1 measured from the three-electrode cyclic voltammetry experiment at 10mVs−1. [Copyright &y& Elsevier]

Abstract: In order to clarify the heat transfer mechanism of supercritical carbon dioxide flowing with a small amount of lubricating oil, visualization experiments were conducted using two sight glass tubes with inner diameters of 2 and 6mm. The visualization images were recorded using a high-speed CCD camera with shutter speed changing from 500 to 10,000pps (pictures per second). PAG-type oil, which is partially miscible with supercritical carbon dioxide, was used. The experiments were conducted with lubricating oil concentrations of 1 and 5wt%, pressures between 8 and 10MPa, and mass fluxes between 200 and 1200kgm−2 s−1. The visualization images revealed that the two-phase flow pattern inside the gas cooler was determined by many factors, including the tube diameter, oil concentration, temperature, pressure, and mass flux. For a small size tube of 2mm ID, the formation of both oil droplets in the bulk region and an oil film along the inner wall of the tube was confirmed. At low temperatures, a large number of oil droplets were observed flowing with CO2 with a slip ratio of approximately 0.7. With an increase in the bulk temperature, both the dimension and number of oil droplets entrained with CO2 decreased, and the flow of the oil film became clearly visible. For a large tube of 6mm ID, the flow pattern at a low mass flow rate was a separated wavy flow; with an increase in mass flow, the flow pattern changed to annular flow, which corresponds to a distinct decrease in the heat transfer coefficient due to the heat resistance of oil layer. The transition of the flow pattern is considered due to the shear stress between the oil layer and bulk CO2. In addition, the dissolution of CO2 into PAG oil as well as the change in the solubility and thermodynamic properties of CO2 with the temperature and pressure makes the prediction of the flow patterns a challenging task. The relationship between the flow pattern and heat transfer characteristics was also discussed. [Copyright &y& Elsevier]

The association and collisional stabilization of the S N2 entrance channel complex [Cl −···CH 3Cl]* is studied in a low-temperature radiofrequency ion trap. The temperature dependence of the ternary rate coefficient is measured and a much stronger inverse temperature dependence than expected from a simple statistical calculation is found. From these data the lifetime of the transient S N2 complex has been derived as a function of temperature. It is suggested that the inverse temperature dependent rates of nonsymmetric S N2 reactions are related to the observed inverse temperature dependence of the transient ion-dipole complexes. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the supply and preservation of glycerol dibiphytanyl glycerol tetraethers (GDGTs) in marine sediments helps inform their use in paleoceanography. Compound-specific radiocarbon measurements of sedimentary alkenones from multiple environments have been used to gain insight into processes that affect paleotemperature reconstructions. Similar analyses are warranted to investigate how analogous processes affecting GDGTs impact TEX86 paleotemperatures. Here we present radiocarbon measurements on individual GDGTs from Bermuda Rise and Santa Monica Basin sediments and discuss the results in the context of previous studies of co-depositional alkenones and foraminifera. The 14C contents of GDGTs and planktonic foraminifera in Bermuda Rise are very similar, suggesting a local source; and TEX86-derived temperatures agree more closely with foraminiferal temperatures than do temperatures. In contrast, GDGTs in Santa Monica Basin are depleted in 14C relative to both alkenones and foraminifera, and TEX86 temperatures agree poorly with known surface water values. We propose three possible factors that could explain these results: (i) GDGTs may be labile relative to alkenones during advective transport through oxic waters; (ii) archaeal production deep in the water column may contribute 14C-depleted GDGTs to sediments; and (iii) some GDGTs also may derive from sedimentary archaeal communities. Each of these three processes is likely to occur with varying relative importance depending on geographic location. The latter two may help to explain why TEX86 temperature reconstructions from Santa Monica Basin do not appear to reflect actual sea surface temperatures. Terrigenous GDGTs are unlikely to be major contributors to Bermuda Rise or Santa Monica Basin sediments, based on values of the BIT index. The results also indicate that the crenarchaeol regioisomer is governed by processes different from other GDGTs. Individual measurements of the crenarchaeol regioisomer are significantly depleted in 14C relative to co-occurring GDGTs, indicating an alternative origin for this compound that presently remains unknown. Re-examination of the contribution of crenarchaeol regioisomer to the TEX86 index shows that it is a significant influence on the sensitivity of temperature reconstructions. [Copyright &y& Elsevier]

An exploration of the nickel malatebpa system under hydrothermal conditions, has led to the isolation of a novel framework {[NiHmalbpa]·2.5H2O}n1 Hmal malate dianion, bpa 1,2bi4pyridylethane. Singlecrystal Xray analyses reveal that it crystallizes in the orthorhombic space group Fdd2. a 21.994413 Å,b33.336919 Å,c 10.39695 Å, ? 90°. The NiIIions are linked into an extended helical chain viaHmal molecules. Further these chains are united together through the bridging bpa to form a 2D grid layer, which exhibits a typical 6,3 topological network. © 2008 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

Lack of information during the growth of carbon nanotubes has hindered efforts to understand the growth mechanism of these unique nanoscale structures. Here, we report that Multiwalled carbon nanotubes with bambooshaped structure may be synthesized by solvothermal method at 300°C using benzene as carbon source and Zn as catalyst. We have obtained direct experimental information on the growth under Transmission electron microscopy. It has been shown that all the compartments of bamboolike tube successively joined leading to the formation of regularly segmented nanobamboos. © 2008 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

Abstract: The main objective of this study is to present the reliability estimation studies for the main truss components as well as the entire structural system of a long span truss bridge which is the longest in its category in the USA. It is possible to assess the safety level of a long span bridge by using a probabilistic approach in terms of its component and system reliability indices. However, most of the older long span bridges were designed based on allowable stress design and it is not possible to quantify their reliability. The reliability analysis in this study is based on the distributions estimated for dead, live and wind loads. The bridge was also subjected to long term structural health monitoring where large amount of input and response data have been collected. Analysis of the long term monitoring data revealed distinct structural behavior in terms of patterns and magnitudes under various external loading effects. As an example, it is shown that the structural responses due to temperature are not very easy to conceptualize and subsequently model using conventional analysis methods. In order to explore the effects of temperature on the structure and to include the long term monitoring data in reliability estimation, temperature-induced responses are also incorporated in the analysis. It is seen that the responses due to temperature have a significant effect on the overall system reliability. [Copyright &y& Elsevier]

Spinel ferrite, MFe 2O 4(M = Co, Ni), ribbons with nanoporous structure were prepared by electrospinning combined with sol−gel technology. The ribbons were formed through the agglomeration of magnetic nanoparticles with PVP as the structure directing template. The length of the polycrystalline ribbons can reach millimeters, and the width of the ribbons can be tuned from several micrometers to several hundred nanometers by changing the concentration of precursor. The nanoporous structure was formed during the decomposition of PVP and inorganic salts. The ribbons exhibited weak saturation magnetizations and low coercivities at room temperature, but at low temperature, saturation magnetizations and coercivities increased a lot, especially for CoFe 2O 4ribbons, reaching 72 emu/g and 1.45 T at 2 k, respectively. These novel magnetic ribbons can potentially be used in micro/nano electronic devices, gas-sensors, and catalysts. [ABSTRACT FROM AUTHOR]

We studied the thermal diffusion behavior of the nonionic surfactant solutions C 12E 6/water and C 12E 5/water at different concentrations and temperatures using thermal diffusion forced Rayleigh scattering (TDFRS). Two different types of TDFRS setups have been applied. In the classical TDFRS, we use an argon laser to write the optical grating into the sample by using a small amount of ionic dye to convert the optical grating into a temperature grating. In the other setup, called IR-TDFRS, we use an infrared laser as the writing beam, which utilizes the water absorption band to convert the optical grating into a temperature grating. The measurements by IR-TDFRS show a one-mode signal for all concentrations and temperatures, while the signal in the classical TDFRS consists of two modes for higher temperatures and lower surfactant concentrations (Ning, H.; et al. J. Phys. Chem. B2006, 110, 10746). We find good agreement between the Soret coefficient determined in the IR-TDFRS and the one derived from the first fast mode in the previous studies. The Soret coefficient of the nonionic solutions is positive and enhanced at the critical point. In general, the Soret coefficient of the micelles tends to increase with temperature. We found that the presence of the second mode observed in the classical TDFRS is related to the addition of the ionic dye, but even with the ionic dye it is not possible to observe a second mode in the IR-TDFRS. The origin of the second mode is discussed in terms of charged micelles and an inhomogenous dye distribution in the temperature gradient. [ABSTRACT FROM AUTHOR]

We calculate the Casimir effect at finite temperature in Minkowski spacetime by using statistical method, the approximate expressions of the Casimir effect in the low and high temperature limits are also discussed. Then employing some general properties of the renormalized stress tensor, we obtain the Casimir energy stress tensor in Hartle-Hawking state. [ABSTRACT FROM AUTHOR]

This investigation represents a first attempt to gain a quantitative estimate of the effects of the anions sulfate, citrate, acetate, chloride and thiocyanate on the thermodynamic stability (Δ G°) of a model globular protein in ice at −15 °C. The method, based on guanidinium chloride denaturation of the azurin mutant C112S from Pseudomonas aeruginosa, distinguishes between the effects of cooling to subfreezing temperatures from those induced specifically by the formation of a solid ice phase. The results confirm that, both in liquid and frozen states, kosmotropes (sulfate, citrate and acetate) increase significantly protein stability, relative to chloride, whereas the chaotrope thiocyanate decreases it. Throughout, their stabilizing efficacy was found to rank according to the Hofmeister series, sulfate > citrate > acetate > chloride > thiocyanate, although the magnitude of Δ(Δ G°) exhibited a distinct sensitivity among the anions to low temperature and to ice formation. In the liquid state, lowering the temperature from +20 to −15 °C weakens considerably the stabilizing efficacy of the organic anions citrate and acetate. Among the anions sulfate stands out as the only strong stabilizer at subfreezing temperatures while SCN −becomes an even stronger denaturant. Freezing of the solution in the presence the “neutral” salt NaCl destabilizes the protein, Δ G° progressively decreasing up to 3−4 kcal/mol as the fraction of liquid water in equilibrium with ice ( VL) is reduced to less than 1%. Kosmotropes do attenuate the decrease in protein stability in ice although in the case of citrate and acetate, their efficacy diminishes sharply as the liquid fraction shrinks to below 2.7%. On the contrary, sulfate is remarkable for it maintains constantly high the stability of azurin in liquid and frozen solutions, down to the smallest VL(0.5%) examined. Throughout, the reduction in Δ G° caused by the solidification of water correlates with the decrease in the denaturant mvalue, an indirect indication that protein−ice interactions generally lead to partial unfolding of the native state. It is proposed that binding of the kosmotropes to the ice interface may inhibit protein adsorption to the solid phase and thereby counter the ice perturbation. [ABSTRACT FROM AUTHOR]

Abstract: A model displaying river water temperatures was established, and applied to a small river basin. Based on the results, the effects of the alteration of the river basin on the budget and river water temperature were discussed. The model was a multi-layer mesh-typed runoff model, and the behavior of water and heat transference was depicted. Also, in order to verify the model, the daily changes of streamflow and river water temperature were measured and compared with the model results. From the calculation, the flow rate and river water temperature profile agreed well with the measured ones along the streamline. Using the model, the effects of deforestation and air temperature rise on river water temperature were discussed. With deforestation, the temperature in summer was calculated to rise and fall in winter. This was explained by the change of flow pass of surface and subsurface. The air temperature was thereafter changed in the model. From the simulation under the air temperature rises, the daily air temperature was evenly changed through a year, and the ratio of the change of the river water temperature to the air was less than unity (i.e., >1°Criver water/°Cair). By close investigation of the model calculation, the most influential factor was determined to be subsurface temperature. The rise of surface temperature was also less than unity, due to the enhancement of heat loss with the augmentation of evaporation at the surface, and because the subsurface temperature is calculated on the surface temperature as boundary condition, rise of subsurface temperature was also less than unity. Overall, the mechanism of the alteration of river water temperature was described as follows: with the change of river basin land use or meteorological conditions, the pass of subsurface flow is changed, and the streamflow and river water temperature are also changed. [Copyright &y& Elsevier]

Abstract: High-chromium ferritic–martensitic steels are candidate structural materials for high-temperature applications in fusion reactors and accelerator driven systems (ADS). Cr concentration has been shown to be a key parameter which needs to be optimized in order to guarantee the best corrosion and swelling resistance, together with the minimum embrittlement. The behavior of Fe–Cr model alloys with different Cr concentrations (0, 2.5, 5, 9 and 12wt%Cr) has been studied. Tensile tests have been performed in order to characterize the flow properties in the temperature range from −160°C to 300°C. The trend of the yield strength with temperature shows that the strain hardening is the same for all materials at low temperatures, even though they have different microstructures. The same materials have been neutron-irradiated at 300°C in the BR2 reactor of SCK·CEN, up to three different doses (0.06, 0.6 and 1.5dpa). The results obtained so far indicate that even at these low doses, the Cr content affects the hardening behavior of Fe–Cr binary alloys. Using the Orowan mechanism, the TEM observed microstructure provides an explanation of the obtained hardening but only at the very low dose, 0.06dpa. At higher doses, other hardening mechanisms are needed. [Copyright &y& Elsevier]

Abstract: Tensile specimens of 9Cr–1Mo (EM10) and mod 9Cr–1Mo (T91) martensitic steels in the normalized and tempered metallurgical conditions were irradiated with high energy protons and neutrons up to 20dpa at average temperatures up to about 360°C. Tensile tests were carried out at room temperature and 250°C and a few samples were tested at 350°C. The fracture surfaces of selected specimens were characterized by Scanning Electron Microscopy (SEM). While all irradiated specimens displayed at room temperature considerable hardening and loss of ductility, those irradiated to doses above approximately 16dpa exhibited a fully brittle behaviour and the SEM observations revealed significant amounts of intergranular fracture. Helium accumulation, up to about 0.18at.% in the specimens irradiated to 20dpa, is believed to be one of the main factors which triggered the brittle behaviour and intergranular fracture mode. One EM10 and one T91 specimen irradiated to 20dpa were annealed at 700°C for 1h following irradiation and subsequently tensile tested. In both cases, a remarkable recovery of ductility and strain-hardening capacity was observed after annealing, while the strength remained significantly above that of the unirradiated material. [Copyright &y& Elsevier]

We study a dynamic process of disentanglement by considering the time evolution of bound entanglement for a quantum open system, two qutrits coupling to a common environment. Here, the initial quantum correlations of the two qutrits are characterized by the bound entanglement. Both bosonic and spin environments are considered. We found that the bound entanglement displays collapses and revivals, and it can be stable against small temperature and time change. The thermal fluctuation effects on bound entanglement are also considered. [ABSTRACT FROM AUTHOR]

Abstract: Within this study the potential of thermotropic layers to prevent overheating of an all-polymeric solar collector is evaluated by theoretical modeling. The investigations show that collector stagnation temperatures can be reduced to temperatures between 80 and 90°C by using thermotropic layers either in the glazing or on the absorber. For overheating protection to a maximum temperature of 80–90°C a residual solar transmittance of the thermotropic layer below 0.25 in the opaque state (>0.85 in clear state) is effectual. The required switching temperature is dependent on the collector configuration. [Copyright &y& Elsevier]

This study attempts to find possible linkages between the NCP index and the winter temperature variability over Iran. The investigation is based on statistical analysis of simple, partial and multiple correlations and also evaluation of composite maps of the extreme NCP index and maps of correlation between atmospheric variables and the temperature time series. Our results show that the NCP has a strong negative correlation with the winter temperature in Iran. Furthermore, combination of both the NCP and the AO (Arctic Oscillation) indices improve the correlations in all stations, implying both NCP and AO can be considered as major patterns for explaining the Iranian winter temperature variability. The results show that the positive NCP is associated with enhanced precipitation and cloudy conditions, consequently causing below normal temperature over Iran. The anomalies of OLR in this phase are also negative, implying a cloudy sky. For the negative NCP phase these results are completely reversed. The correlation maps indicate that the NCP is negatively/positively correlated with winter Outgoing Long-wave Radiation/precipitation over Iran. The results also show that the SLP and GPH patterns are quite different for the positive and negative NCP phases over Iran. During the negative NCP a small cyclone is formed over the Arabian Sea causing a strong easterly towards Iran. During the positive NCP this cyclone is removed. Our results show that for the positive NCP years an upper-level trough is formed over northern Iran and the eastern Mediterranean. For the negative NCP years this trough becomes weak and is located over central European regions. This trough is closely linked with the winter temperature over Iran. This is expressed by a high correlation between 500-hPa geopotential height at this region and Iranian winter temperature. [ABSTRACT FROM AUTHOR]

Variations in rail temperature are responsible for a large proportion of weather related delays on the rail network. Tracks are pre-stressed to withstand a specified range of temperature, but once the range is breached the rail can distort causing tension cracks in cold weather and buckling in hot weather. Currently, blanket speed restrictions are imposed at certain temperature thresholds to ensure passenger safety. This paper discusses the measurement and modelling of rail temperature data at both a specially constructed test track and a ‘live’ main-line track. Although, empirical techniques are presently used to derive rail temperatures from air temperatures, this approach is limited as it fails to take into account other ambient weather conditions. To address this, a road weather model was converted to model the energy balance of a rail. This enables rail temperatures to be forecasted for the entire diurnal cycle and at a variety of synoptic conditions. The physical model shows significant forecasting ability, outperforming empirical techniques with a mean bias of 0.2 °C (RMSE = 2.56°) for a 200 day measurement campaign. [ABSTRACT FROM AUTHOR]

Abstract: Thermal behavior of energetic materials is critical to safe production, storage, handling or even demilitarization. In this work, the thermal behavior of Al, Mg, CuO, KMnO4 and also three mixtures containing Al+CuO, Mg+CuO and Mg+KMnO4 were studied experimentally using differential scanning calorimetry and thermogravimetry. These mixtures are sometimes used as pyrotechnic mixtures in military industries. Also, the influence of different heating rates (5, 10, 15 and 20°C/min) on the DSC behavior of the mixtures was verified. The results showed that as the heating rate was increased, melting points and ignition temperatures of the mixtures were increased. On the other hand, TG–DSC analysis for Mg+KMnO4 mixture indicates that this mixture melts at 283.0°C and decomposed at 292.1°C. By replacing KMnO4 with CuO as the oxidizer of the magnesium, these temperatures enhanced to 368.7°C and 408.3°C, respectively. However, replacing Mg with Al in the Mg/CuO mixture decreases the melting and ignition temperatures of the mixture to 231.4°C and 271.9°C, respectively. The activation energy for each pyrotechnic mixture was computed. Also, the values of ΔS #, ΔH # and ΔG # of their reaction were calculated. [Copyright &y& Elsevier]

Abstract: An open-end coaxial probe is combined with a planar patch-clamp system to apply electric fields with GHz frequencies during conventional patch-clamp measurements. The combination of pulsed microwave irradiation and lock-in detection allows for the separation of fast and slow effects and hence facilitates the identification of thermal effects. The setup and the influence of radiation on the patch-clamp current are thoroughly characterized. For the independent optical verification of heating effects, a temperature microscopy technique is applied with high spatial, temporal and temperature resolution. It is shown that the effect of radiation at GHz frequencies on whole cell currents is predominantly thermal in nature in the case of RBL cells with an endogenous Kir 2.1 channel. [Copyright &y& Elsevier]

The surface of nanopores in colloidal films, assembled from 205 nm silica spheres, was modified with poly(N-isopropylacrylamide), PNIPAAM, brushes using surface-initiated ATRP. The polymer thickness inside nanopores was controlled by the polymerization time. The diffusion through PNIPAAM-modified colloidal films was measured using cyclic voltammetry and studied as a function of temperature and polymer brush thickness. Nanopores modified with a thin PNIPAAM brush exhibited a positive gating behavior, where diffusion rates increased with increasing temperature. Nanopores modified with a thick PNIPAAM layer showed a negative gating behavior where diffusion rates decreased with increasing temperature. The observed temperature response is consistent with two transport mechanisms, one in which molecules diffuse through the nanopores whose volume increases with increasing temperature as the PNIPAAM brush collapses onto the nanopore surface (positive gating) and the second one where molecules diffuse through the porous PNIPAAM that fills the entire nanopore opening and collapses onto itself, becoming hydrophobic and impermeable (negative gating). [ABSTRACT FROM AUTHOR]

Abstract: Data from several Huygens probe housekeeping sensors (an engineering accelerometer and housekeeping temperature sensors) are studied to determine how effectively such nonideal instruments may characterize the density or temperature structure of the atmosphere. While only confirming the results of the dedicated atmospheric structure instrument, this exercise is of relevance to possible future missions to various bodies which might not be equipped with such science-grade sensors able to accurately profile the atmosphere top-to-bottom. It is found that for typical engineering accelerometers with 8-bit resolution, the atmosphere density for ∼4 scale heights above the peak deceleration altitude may be recovered. If, as with Huygens, the peak deceleration exceeds the range of the accelerometers, recovery of an additional scale height or so below the peak is still possible, but relies on accurate total velocity knowledge. Engineering temperature sensors can, with care, be analyzed to recover the temperature structure of at least the lowest ∼30km of Titan''s atmosphere. Fortunately, in the case of Huygens, data from the surface after landing were available to constrain models of heat leaks which offset the observed temperature from that of the ambient air during descent; data from before and during the entry phase on other missions would be similarly useful. When corrections are made for the estimated heat transfer processes, the atmospheric temperature can be recovered to within about 3K. [Copyright &y& Elsevier]

Abstract: Current methods for deriving thermal inertia from spacecraft observations of planetary brightness temperature generally assume that surface properties are uniform for any given observation or co-located set of observations. As a result of this assumption and the nonlinear relationship between temperature and thermal inertia, sub-pixel horizontal heterogeneity may yield different apparent thermal inertia at different times of day or seasons. We examine the effects of horizontal heterogeneity on Mars by modeling the thermal behavior of various idealized mixed surfaces containing differing proportions of either dust, sand, duricrust, and rock or slope facets at different angles and azimuths. Latitudinal effects on mixed-surface thermal behavior are also investigated. We find large (several 100 J m−2 K−1 s−1/2) diurnal and seasonal variations in apparent thermal inertia even for small (∼10%) admixtures of materials with moderately contrasting thermal properties or slope angles. Together with similar results for layered surfaces [Mellon, M.T., Putzig, N.E., 2007. Lunar Planet. Sci. XXXVIII. Abstract 2184], this work shows that the effects of heterogeneity on the thermal behavior of the martian surface are substantial and may be expected to result in large variations in apparent thermal inertia as derived from spacecraft instruments. While our results caution against the over-interpretation of thermal inertia taken from median or average maps or derived from single temperature measurements, they also suggest the possibility of using a suite of apparent thermal inertia values derived from single observations over a range of times of day and seasons to constrain the heterogeneity of the martian surface. [Copyright &y& Elsevier]

Abstract: The separation of carbon dioxide (CO2) from methane (CH4) by using a gas–liquid membrane contactor was studied in order to confirm the potential of the process. The experiments were performed in a membrane contactor constructed with 0.2μm pore size microporous PVDF hollow fibers. Pure water, aqueous sodium hydroxide (NaOH) solution and aqueous monoethanolamine (MEA) solution were employed as the absorbents. Sodium chloride (NaCl) was also used as an additive in the NaOH aqueous solution. The effects of operating parameters such as the gas and liquid velocity, concentration of NaOH solution, absorbent temperature, and NaCl concentration on the CO2 flux were investigated along with the mass transfer analysis of the process. In addition, the impacts of the flow pattern and the membrane module packing density as well as the long-term performance were also investigated, aiming to obtain a full picture and a deep insight on the system. It was found that the CO2 flux was enhanced by the increase of NaOH solution concentration, NaOH solution temperature and the CO2 volume fraction in the feed stream, but the increase of water temperature resulted in decreasing the CO2 flux. The retentate selectivity obtained in this work was not satisfactory due to the laboratory scale of the membrane module used. However, the percentage of CH4 recovery was very high, suggesting that no significant CH4 loss took place during the operation. Counter-current flow mode took the advantage of higher mass transfer over co-current one, and the CO2 flux increased with increasing membrane module packing density. Long-term performance tests showed that the NaOH solution was more suitable than other absorbents to be applied to the PVDF microporous hollow fiber contactors, as the NaOH aqueous solution can provide a higher separation performance and the CO2 flux was kept almost unchanged over a long period of operation. Furthermore, the PVDF membrane gave the membrane resistance around 22% of the total resistance for pure CO2 absorption in water. [Copyright &y& Elsevier]

Abstract: Samples with nominal starting compositions of Tl0.5Pb0.5Sr2−y Yb y CaCu2O7 (y =0–0.6) were synthesized using conventional solid-state synthesis method. Temperature dependent electrical resistance measurements on the series showed that the normal state behavior and superconducting properties can be controlled by adjusting Yb concentration to achieve maximum critical temperature (T c). The best superconducting behavior for the series was observed for Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 with onset critical temperature (T conset) of 105K. Results of critical temperature (T c) measurements, microstructure investigation using scanning electron microscope (SEM) and powder X-ray diffraction (XRD) analysis are presented. The effects of Yb substitutions are discussed in terms of T c, Tl1212 phase formation and the concept of average Cu valence. [Copyright &y& Elsevier]

Abstract: Layered-silicate, especially montmorillonites (MMTs) reinforced polymer nanocomposites, have attracted considerable interest during the recent years due to the dramatic enhancements in physical, thermal and mechanical properties of polymer materials at low filler loading. Depending on the interaction between MMTs and polymers, different microstructured nanocomposites ranging from immiscible to intercalated to exfoliated can be synthesized. In this paper, organoclay reinforced polyamide 6 (PA 6) nanocomposites have been prepared by a simple and versatile method—melt intercalation using extrusion. Their structural, thermal and mechanical properties have been systematically investigated with advanced facilities. It was found from transmission electron microscopy and X-ray diffraction evaluations that the organoclays were intercalated and dispersed evenly in the matrix. Moreover, the existence of the organoclay also affected the crystalline and thermal behavior of the polymer, the crystalline temperature, melting temperature and decomposition temperature of the nanocomposites decreased slightly with the organoclay fraction. Comparing to the thermal properties, the mechanical properties were significantly improved by the incorporation of the organoclay. The elastic modulus and tensile strength of the PA 6 nanocomposites with 7.5wt% of organoclay increased by 57.44% and 18.37%, respectively, compared to the pure PA 6. [Copyright &y& Elsevier]

This article studies the feasibility of noninvasive temperature estimation by detecting echo-strain including thermal expansion in therapeutic ultrasound treatment. This technique evaluates distributions of echo-strain and temperature inside the tissue by detecting echo signals pre- and post-heating, in combination with the temperature dependence of sound speed and thermal expansion. In the computer simulation and experimental study, echo signals pre- and post-heating are acquired and then the temperature elevation is evaluated by correlation analysis. Results demonstrate that this technique can effectively extend the measured temperature range up to 75°C with an accuracy of ±2°C. [ABSTRACT FROM AUTHOR]

Abstract: There is little agreement regarding the importance of anelastic contributions to the temperature dependence of seismic wave velocities. Some studies consider the anelastic contribution to be negligible, whereas others argue that it may be as important as the purely elastic contribution. In order to evaluate these claims, we review physically plausible models for mantle relaxation processes and construct a model of activation enthalpy based on solid state physics as well as on recent experimental results. We then deduce self-consistent 1-D Q profiles and evaluate the anelastic contribution to the temperature dependence of V s and V p . Physically plausible values of activation enthalpies yield anelastic contributions that increase with depth and account for at least 20% of the velocity temperature derivatives at 2600 km. We show that anelasticity may significantly moderate temperature variations in hot (slow velocity) zones. This suggests that inferred lateral changes in temperature, as well as arguments regarding the presence of chemical heterogeneity, and/or temperature induced phase transformations, are likely to be significantly affected by anelastic effects in the mantle. We also compute values of the dimensionless parameters R s/p , R ϕ/s , and R ρ/s . We find that anelasticity can either increase or decrease R s/p , but the magnitude of the correction, of the order of 15%, is smaller than the uncertainty in the elastic value. Anelasticity cannot change the sign of R ϕ/s and R ρ/s , but it can decrease their values by as much as 50%. However, given current uncertainties in seismic and mineral data, the effects of anelasticity on the dimensionless parameters do not bring any quantitative constraints on lateral variations of temperature, chemical composition and/or mineral phase. [Copyright &y& Elsevier]

Abstract: Four-point conductance measurements of a high temperature annealed monolayer of Pb on Si(557) are combined with tunneling microscopy (STM) and LEED for structural investigations. We found extremely high surface state conductance which becomes quasi-one-dimensional below a critical temperature of T c =78K. The change from low to extremely high conductance anisotropy is associated with a reversible order–disorder phase transition with a temperature dependence ∝1/T +const. along the chains below the phase transition. Below the phase transition order is found simultaneously in the lateral separation between Pb chains and along the chains. There a 10-fold superperiodicity appears. We suggest that strong two-dimensional coupling, leading to electronic stabilization of terraces with a width of lattice constants, results in perfect nesting normal to the chains at E F (below T c), which is the origin of this switching to one-dimensional behavior. Therefore, no metal–insulator transition is expected at low temperature. [Copyright &y& Elsevier]

Abstract: MEMS micro heater devices capable of long-term operation at temperatures up to 1000°C are presented. The enhanced long-term stability has been achieved by employing antimony-doped tin oxide (SnO2:Sb) as a substitute for the conventionally used noble metal heater resistors. A detailed investigation of its high-temperature stability reveals that degradation is caused by out-diffusion of Sb impurities from the SnO2 film. [Copyright &y& Elsevier]

Abstract: We use regional scale numerical models of mantle convection to investigate the simple hypothesis that seismically anomalous thin patches of Earth’s lowermost mantle, termed “ultralow-velocity zones” or ULVZ, are derived from partial melting of ordinary mantle. The models span the lower 500 km of Earth’s mantle, employ both temperature and melting-related contributions to buoyancy, and include a cold randomly moving downwelling introduced from above to maintain a thermal boundary layer. Partial melting of ordinary mantle introduces a ubiquitous partially molten layer above an isothermal core–mantle boundary as a consequence of its isothermal and isobaric conditions, although it naturally develops variations in thickness greater than two orders of magnitude, with the thickest portions occurring at the base of upwelling plumes and a thin layer elsewhere. We find that only a dense partially molten mixture produces partial melt distributions that are compatible with seismic observations of ULVZ; however, if such a melt percolates downward a dense basal liquid layer accumulates above the core–mantle boundary. The apparent requirement of a volumetrically dense and non-percolating melt phase in the lowermost mantle presents serious problems for the hypothesis that ULVZ arise from melting of ordinary mantle, and suggests that such features likely form as a consequence of more complex processes. Furthermore, these considerations suggest that the solidus of ordinary mantle is a reasonable upper bound on the present day temperature of the CMB. [Copyright &y& Elsevier]