The influence of polymerization time and dopant concentration on the absorption of microwave radiation in conducting polypyrrole coated textiles

Temperature changes in conducting polypyrrole/para-toluene-2-sulphonic acid (PPy/pTSA) coated nylon textiles due to microwave absorption in the 8–9 GHz and 15–16 GHz frequency ranges were obtained by a thermography station during simultaneous irradiation of the samples. The temperature values are compared and related to the amounts of reflection, transmission and absorption obtained with a non-contact free space transmission technique, indicating a relationship between microwave absorption and temperature increase. Non-conductive samples showed no temperature increase upon irradiation irrespective of frequency range. The maximum temperature difference of around 4 °C in the conducting fabrics relative to ambient temperature was observed in samples having 48% absorption and 26.5 ± 4% reflection. Samples polymerized for 60 or 120 min with a dopant concentration of 0.018 mol/l or polymerized for 180 min with a dopant concentration of 0.009 mol/l yielded optimum absorption levels. As the surface resistivity decreased and the reflection levels increased, the temperature increase upon irradiation reduced.

Thermoenergetics of pre-moulting and moulting kookaburras (Dacelo novaeguineae): they're laughing.

We examined the effect of temperature on resting metabolic rate in seven field-captured laughing kookaburras (Dacelo novaeguineae) during late winter and early spring. Basal metabolic rate averaged 201±3.4 ml O₂ h^–1 (0.603 ml O₂ g^–1 h^–1). Overall thermal conductance (K_o) declined with ambient temperature (T_a) and averaged 0.026 ml O₂ g^–1 h^–1 °C^–1 at T_as<10 °C. Day-night differences in body temperatures (2.6 °C) and in alpha-phase versus rho-phase minimum metabolic rates were much greater (33%) than predicted for 340-g nonpasserine birds and suggest that these animals operate as low-metabolic intensity animals in their rest phase, but normal-metabolic intensity animals during their active phase. Metabolic rate was measured in four of the same birds undergoing moult. Thermal conductance increased to 60% above pre-moult values about 6 weeks after moult began. Basal metabolic rate of moulting birds showing peak thermal conductance readings averaged 17 ml O₂ h^–1 higher than pre-moult measurements. Although this increase was not statistically significant, we believe the moult costs of kookaburras are too low to overcome the inherent variability of BMR determination. We suggest that moult costs of kookaburras are only somewhat higher than the measured costs of protein synthesis of other endotherms.

Building surfaces and their effect on the urban thermal environment

Use of high reflectance surfaces reduces the amount of solar radiation absorbed through building envelopes and urban structures and thus keeping their surfaces cooler. The cooling energy savings by using high reflectance surfaces have been well documented. Higher surface temperatures add to increasing the ambient temperature as convection intensity is higher. Such temperature increase has significant impacts on the air conditioning energy utilization in hot climates. This study makes use of numerical simulations to analyze the effect of commonly used building materials on the air temperature. A part of the existing CBD (Central Business District) area of Singapore was selected for the study. A series of Computational Fluid Dynamics (CFD) simulations have been carried out using the software CFX-5.6. It was found that at low wind speeds, the effect of materials on the air temperature was significant and the temperature at the middle of a narrow canyon increased up to 2.5[degrees]C with the facade material having lower reflectance.

Effect of materials on the urban thermal environment a CFD simulation approach

Use of high albedo materials reduces the amount of solar radiation absorbed through building envelops and urban structures and thus keeping their surfaces cooler. The cooling energy savings by using high albedo materials have been well documented. Higher surface temperatures add to increasing the ambient temperature as convection intensity is higher. Such temperature increase has significant impacts on the air conditioning energy utilization in hot climates. This study makes use of a parametric approach by varying the temperature of building facades to represent commonly used materials and hence analyzing its effect on the air temperature through a series of CFD (Computational Fluid Dynamics) simulations. A part of the existing CBD (Central Business District) area of Singapore was selected for the study. Series of CFD simulations have been carried out using the software CFX-5.6. Wind tunnel experiments were also conducted for validation. It was found that at low wind speeds, the effect of materials on the air temperature was significant and the temperature at the middle of a narrow canyon increased up to 2.52°C with the façade material having lowest albedo.

Physiology and biochemistry of budburst in Vitis vinifera

Both the physiological and biochemical control of budburst in the grapevine, Vitis Vinifera L. were investigated. It was found that the accuracy of a predictive model for grapevine budburst based on ambient temperature was limited under the experimental conditions. There was a significant correlation of 4.7 ± 0.3 days between the days of maximal xylem exudation and budburst over the 3 years of investigation. The co-relationships between daily xylem exudate volume and a range of environmental parameters were considered. It was found that soil temperature was highly correlated against daily xylem exudation. Ambient temperature and soil moisture were significantly correlated with xylem exudation, however the coefficients of correlation were much lower than that of soil temperature. Rainfall showed only a very limited correlation with daily xylem exudate flow. Seasonal variations in the pH and the carbohydrate and inorganic nutrient concentrations of xylem exudate were investigated. Exudate carbohydrate concentrations fell from 660 µM before the day of maximal xylem exudation to zero levels within 4 weeks. Xylem exudate pH was found to consistently fall to a minimum at the time of maximal exudate flow. Exudate concentrations of the metallic cofactors Ca, K, Mg, Mn and Zn varied directly with daily exudate flow, suggesting some sort of flow-dependent mobilisation of these nutrients. A growth promontory oligosaccharide fraction was prepared by partial acid hydrolysis of grapevine primary cell wall material. This fraction significantly increased control growth of the Lemna minor L. bioassay over a limited ‘window’ of bioactivity. A growth inhibitory oligosaccharide fraction, similar in activity to abscisic acid was isolated from grapevine xylem exudate prior to budburst. The exudate concentration or efficacy of this substance declined after budburst such that there was no apparent growth inhibition. A model is proposed for grapevine budburst whereby an oligosaccharide growth inhibitor is gradually removed from the xylematic stream under the effects of soil temperature, allowing the surge of metabolic activity and vegetative growth that constitute budburst.

Effect of Jersey type on thermoregulatory responses during exercise in a warm humid environment

The thermoregulatory responses of subjects wearing two different forms of rugby league jersey, one with plastic sponsorship recognition and numbering (trial Gl) and one without (trial G2), and a lightweight alternative (trial G3), were compared with a trial without any form of upper body garment (trial GO). Ten male volunteers, mean age 20.9 (±2.3) years, height 179.8 (±4.7) cm, weight 80.2 (±8.9) kg, and body surface area 1.99 (±0.13) m2, participated in this study. Subjects had a mean maximal oxygen uptake capacity of 56.0 (±6.3) ml.kg.min-1 and a sum of 8 skinfolds of 80.6 (±23.8) mm. Subjects were exercised at approximately 50% of maximal oxygen uptake in a warm humid environment for 50 minutes. Mean ambient temperature was 27.6°C (±0.32) with a relative humidity of 64.7% (±1.44). Measurements of core and skin (7 sites) temperature, heart rate, oxygen uptake, plasma volume, peak lactate concentration, and pre- and post-trial body weight, hematocrit and garment weight were recorded. The statistical results showed that all subjects experienced significant (p ≤.0001) decreases in body weight representing a percentage decrease ranging from 1.2-1.3%. No significant difference was found between trials with respect to body weight change. No significant effect of garment type was found on pre- and post-trial hematocrit, plasma volume changes or peak blood lactic acid concentration. However, mean peak lactate was highest for trial Gl (5.6 mmol.L-1 ±2.2) and lowest for trial G3 (4.6 mmol.L-1 ±1.27). Post-trial core temperature was significantly (p≤ .0001) higher than the resting value; no significant difference was found between trials. The mean absolute increase for all experimental trials was 0.9°C. A significant (p≤.005) difference between mean total (7 sites) skin temperature was found with a post-hoc test revealing that trials Gl and G2 were significantly higher than trial GO; no significant difference was found when comparing trial G3 with trial GO or when comparing the garments between each other. Mean skin temperature under the garment (4 sites) was found to be significantly (p≤.05) higher for all trials involving a garment when compared with mean skin temperature outside (3 sites) the garment; no significant difference was found between trials. Mean oxygen uptake was significantly different between trials (p≤.005), with trial Gl and G3 found to be significantly lower than trial GO; no difference was found when comparing the garments with each other. Post-trial garment weights were significantly (p≤.001) heavier than pre-trial and were significantly (p≤.0001) different when compared with each other. There was no significant effect on heart rate, haematocrit, plasma volume changes, peak blood lactic acid concentration, or core temperature due to garment type. However, differences in skin temperature suggest that the garment used in trial G3 may have a benefit. Further research should consider the impact of increased exercise intensity and/or environmental temperature and humidity on the measured parameters while wearing the garments described in this study.

Study of the creep behaviour of stitched woven composites

An experimental and theoretical study of the tensile creep behaviour of woven fibre composites stitched with cotton, and carbon threads, along or perpendicular to the loading direction with different densities is presented. The results of creep tests, conducted at ambient temperature and various elevated temperatures with low to high stress levels are reported.

High mobility I− / I3− redox couple in a molecular plastic crystal: A potential new generation of electrolyte for solid-state photoelectrochemical cells

A series of new electrolyte materials based on a molecular plastic crystal doped by different iodide salts together with iodine have been prepared and characterized by thermal analysis, ionic conductivity, electrochemical and solid-state NMR diffusion measurements. In these materials, the plastic crystal phase of succinonitrile acts as a good matrix for the quaternary ammonium based iodides and iodine and appears to act in some cases as a solid-state “solvent” for the binary dopants. The materials were prepared by mixing the components in the molten state with subsequent cooling into the plastic crystalline state. This resulted in waxy-solid electrolytes in the temperature range from − 40 to 60 °C. The combination of structural variation of the cations, and fast redox couple diffusion (comparable with liquid-based electrolytes), as well as a high ionic conductivity of up to 3 × 10^{− 3} S cm^{− 1} at ambient temperature, make these materials very attractive for potential use in solid-state photoelectrochemical cells.

Microstructural and molecular level characterisation of plastic crystal phases of pyrrolidinium trifluoromethanesulfonyl salts

Ambient temperature conductive plastic crystal phases of alkylmethylpyrrolidinium trifluoromethanesulfonyl amide (TFSA) salts are studied using positron annihilation lifetime spectroscopy (PALS) to examine the role of vacancy size and concentration in conductivity. The ethyl methylpyrrolidinium TFSA salt (P₁₂ TFSA) has larger vacancies and a greater concentration of vacancies than the dimethylpyrrolidinium TFSA salt (P₁₁ TFSA) over the temperature range investigated. The relative vacancy size and concentration vary with temperature and reflect the solid–solid transitions as measured by differential scanning calorimetry (DSC). P₁₂ TFSA has greater conductivity than P₁₁ TFSA and has furthermore been observed to exhibit slip planes at room temperature. P₁₂ TFSA has greater entropy changes associated with solid–solid phase transitions below the melting point than P₁₁ TFSA possibly indicating greater rotational freedom in P₁₂ TFSA. These results support the notion that the diffusion, conduction, and plastic flow properties of the pyrrolidinium TFSA salts are derived from the lattice vacancies.

PEDOT-coated counter electrodes for dye-sensitized solar cells

Poly(3,4-ethylenedioxythiophene) (PEDOT)-coated counter electrodes for dye-sensitized solar cells have been prepared at ambient temperature and without the use of iron-based oxidants, using an ionic liquid for the synthesis of the PEDOT. These electrodes show comparable electrocatalytic performance with conventional Pt-coated counter electrodes (solar cell efficiencies >7.5%).

Maximising trapping efficiency in reptile surveys : the role of seasonality, weather conditions and moon phase on capture success

Context : Designing an appropriate survey protocol requires understanding of how capture rates of target species may be influenced by factors other than on-ground abundance, such as weather conditions or seasonality. This is particularly relevant for ectotherms such as reptiles, as activity can be affected by environmental conditions such as ambient temperature.
Aims : The present study examines factors affecting capture success of reptiles in semi-arid environments of southern Australia, and addresses the following two main questions: (1) what is the influence of weather and seasonal factors on capture rates of reptiles, and (2) what are the implications for developing an effective protocol for reptile surveys?
Methods : We surveyed reptiles using pitfall traps in spring and summer of 2006/07 and 2007/08 at sites (n = 280) throughout the Murray Mallee region of south-eastern Australia. We used mixed-effect regression models to investigate the influence of seasonal and weather-related variables on species’ capture success.
Key results : Total captures of reptiles, and the likelihood of capture of 15 reptile species, increased with rising daily temperature. Greater numbers of individual species were captured during spring than in summer, even though temperatures were cooler. This probably reflects greater levels of activity associated with breeding. Several species were more likely to be captured when maximum or minimum daily temperatures exceeded a certain level (e.g. Lerista labialis, Delma australis, Nephrurus levis). Other factors, such as rainfall and moon phase, also influenced capture success of some species.
Conclusions : Surveys for reptiles in semi-arid environments are likely to capture the greatest diversity of species on warm days in late spring months, although surveys on hot days in summer will enhance detection of particular species (e.g. Morethia boulengeri, Varanus gouldii). We recommend trapping during periods with maximum temperatures exceeding 25–30C and minimum overnight temperatures of 15C. Finally, trapping during rainfall and full-moon events will maximise chances of encountering species sensitive to these variables (blind snakes and geckoes).
Implications : Selecting the most favourable seasonal and weather conditions will help ensure that reptile surveys maximise the likelihood of capturing the greatest diversity of reptiles, while minimising trap-effort required.

Cloud-point extraction of phenanthrene by nonionic surfactants

Extraction and preconcentration of the model polycyclic aromatic hydrocarbon (PAH), phenanthrene, in aqueous solutions by two different kinds of nonionic ethoxylated alcohols, Tergitol 15-S-7 and Neodol 25-7, as extractants was studied at ambient temperature (22°C). Both surfactants have almost the same numbers of hydrocarbons and ethylene-oxide (EO) units, but differ in the location of the alcohols. Neodol 25-7 is a primary alcohol, while Tergitol 15-S-7 is a secondary one. The extraction process is based on the clouding phenomena of these two nonionic surfactants. Addition of sodium sulfate or sodium phosphate could decrease the cloud point temperatures of the surfactant solutions below the ambient temperatures, so that the cloud-point extraction process could be facilitated. Increasing the salt concentration or decreasing the surfactant concentration could improve the preconcentration factor, which is attributable to the decrease in the volume of surfactant-rich phase. Consequently, the recovery efficiency higher than 96% was achieved for phenanthrene in aqueous solution.

A novel cloud-point extraction process for preconcentrating selected polycyclic aromatic hydrocarbons in aqueous solution

A novel but simple cloud-point extraction (CPE) process is developed to preconcentrate the trace of selected polycyclic aromatic hydrocarbons (PAHs) with the use of the readily biodegradable nonionic surfactant Tergitol 15-S-7 as extractant. The concentrations of PAHs, mixtures of naphthalene and phenanthrene as well as pyrene, in the spiked samples were determined with the new CPE process at ambient temperature (23 °C) followed by high performance liquid chromatography (HPLC) with fluorescence detection. More than 80% of phenanthrene and pyrene, respectively, and 96% of naphthalene initially present in the aqueous solutions with concentrations near or below their aqueous solubilities were recovered using this new CPE process. Importantly Tergitol 15-S-7 does not give any fluorometric signal to interfere with fluorescence detection of PAHs in the UV range. No special washing step is, thus, required to remove surfactant before HPLC analyses. Different experimental conditions were studied. The optimum conditions for the preconcentration and determi nation of these selected PAHs at ambient temperature have been established as the following:  (1) 3 wt % surfactant; (2) addition of 0.5 M Na2SO4; (3) 10 min for equilibration time; and (4) 3000 rpm for centrifugal speed with duration of 10 min.

The "refoldability" of selected proteins in ionic liquids as a stabilization criterion, leading to a conjecture on biogenesis

The folding of proteins is usually studied in dilute aqueous solutions of controlled pH, but it has recently been demonstrated that reversible unfolding can occur in other media. Particular stability is conferred on the protein (folded or unfolded) when the process occurs in ‘protic ionic liquids’ (pILs) of controlled proton activity. This activity (‘effective pH’) is determined by the acid and base components of the pIL and is characterized in the present study by the proton chemical shift of the N–H proton. Here we propose a ‘refoldability’ or ‘refolding index’ (RFI) metric for assessing the stability of folded biomolecules in different solvent media, and demarcate high RFI zones in hydrated pIL media using ribonuclease A and hen egg white lysozyme as examples. Then we show that, unexpectedly, the same high RFIs can be obtained in pIL media that are 90% inorganic in character (simple ammonium salts). This leads us to a conjecture related to the objections that have been raised to ‘primordial soup’ theories for biogenesis, objections that are based on the observation that all the bonds involved in biomacromolecule formation are hydrolyzed in ordinary aqueous solutions unless specifically protected. The ingredients for primitive ionic liquids (NH3, CO, HCN, CO2, and water) were abundant in the early earth atmosphere, and many experiments have shown how amino acids could form from them also. Cyclical concentration in evaporating inland seas could easily produce the type of ambient-temperature, non-hydrolyzing, media that we have demonstrated here may be hospitable to biomolecules, and that may be actually encouraging of biopolymer assembly. Thus a plausible variant of the conventional ‘primordial soup’ model of biogenesis is suggested.

Effect of heat stress on glucose kinetics during exercise

To identify the mechanism underlying the exaggerated hyperglycemia during exercise in the heat, six trained men were studied during 40 min of cycling exercise at a workload requiring 65% peak pulmonary oxygen uptake (V˙o 2 peak) on two occasions at least 1 wk apart. On one occasion, the ambient temperature was 20°C [control (Con)], whereas on the other, it was 40°C [high temperature (HT)]. Rates of glucose appearance and disappearance were measured by using a primed continuous infusion of [6,6-2H]glucose. No differences in oxygen uptake during exercise were observed between trials. After 40 min of exercise, heart rate, rectal temperature, respiratory exchange ratio, and plasma lactate were all higher in HT compared with Con (P < 0.05). Plasma glucose levels were similar at rest (Con, 4.54 ± 0.19 mmol/l; HT, 4.81 ± 0.19 mmol/l) but increased to a greater extent during exercise in HT (6.96 ± 0.16) compared with Con (5.45 ± 0.18;P < 0.05). This was the result of a higher glucose rate of appearance in HT during the last 30 min of exercise. In contrast, the glucose rate of disappearance and metabolic clearance rate were not different at any time point during exercise. Plasma catecholamines were higher after 10 and 40 min of exercise in HT compared with Con (P < 0.05), whereas plasma glucagon, cortisol, and growth hormone were higher in HT after 40 min. These results indicate that the hyperglycemia observed during exercise in the heat is caused by an increase in liver glucose output without any change in whole body glucose utilization.