Range Of Environmental Temperatures Research Articles

Multifunctional melt-mixed Ag/TiO2 nanocomposite PP fabrics: Water vapour permeability, UV resistance, UV protection and wear properties

This research deals with the investigating the effect of nanoparticles on the various properties of nanocomposite fabrics produced from melt spinning of various blend ratios of prepared masterbatch containing Ag/TiO2 nanoparticles. The results revealed that the wear properties of modified fabrics improved as compared to pure fabrics with a trend justified considering modulus or crystallinity of fabrics with opposite effects. About 40 % UV protection enhancement has been obtained applying this kind of nanoparticles in the close relationship with the crimp contraction of textured yarns. A considerable improvement in the garment comfort has been recorded for nanocomposite sample containing 1 wt% nanoparticles. The lower permeability at low environment temperature and a higher at higher one, as compared to the pure sample, were obtained using this sample. It is highly interesting that these desirable changes in permeability can be achieved in the range of common environment temperatures (15–35 °C) being adapted to the human body requirements. The changing point is about 25 °C exactly meeting the body requirements by changing environment temperatures. A UV-induced solid state nanocomposite interaction increasing wear properties of UV-irradiated nanocomposite fabrics has been discovered.

Environmental Toxicity Monitoring of Nanomaterials using Vicia Faba GENE-TOX Assay

Environmental Toxicity Monitoring of Nanomaterials using Vicia Faba GENE-TOX Assay

Effect of starvation, body size, and temperature on the onset of metamorphosis in Japanese eel (Anguilla japonica)

We assessed the effects of starvation, body size, and water temperature on the onset of metamorphosis in leptocephali of Japanese eel ( Anguilla japonica Temminck and Schlegel, 1846) as determined by the morphological criteria of proportion, preanal length, and body depth to total length. Leptocephali of mean total length 55.6 mm that had been reared in captivity for 241 days from hatching were divided into unfed (n = 28) and fed (n = 30) groups in triplicate and reared for an additional 2 weeks. The mean percentage of larvae starting metamorphosis within 2 weeks was significantly higher in the unfed than in the fed groups (70% vs. 28.6%), suggesting that food deprivation acted as a cue for metamorphosis. The critical size for metamorphosis was a total length of 50–55 mm; smaller larvae did not start metamorphosis even in the absence of food, whereas larvae reaching that critical size were induced to undergo metamorphosis by starvation. The start of metamorphosis under unfed conditions was independent of diel-varying water temperature (day 23 °C; night 21–29 °C), suggesting a high plasticity in response to a wide range of environmental temperatures. These findings suggest methods for the efficient production of glass eels, as well as new insights into the mechanism of eel metamorphosis.

Synthesization of CNT on Surface of C/C Composites to Stabilize the Coefficient of Friction through a Wide Environmental Temperature Range

Carbon nanotubes (CNTs) were synthesized on the surface of carbon-carbon (C/C) composites by the thermal chemical vapor deposition method. The coefficient of mutual friction between two flat specimens of both modified and unmodified C/C composites were measured at a constant rotational speed under constant applied pressure by using disc-type test apparatus. The effect of CNT synthesization on the mutual friction coefficient and its dependence on test temperature were discussed. Frictional coefficient was high and also stable when the CNTs were synthesized on the surface while the test temperature was changed. The morphology evaluation of the frictional surface after the test suggested that synthesization of CNTs on a frictional surface of a C/C composite was effective in changing the wear mode for stability of the coefficient of friction according to the change of environmental temperature.

Effect of stirring conditions on cellulose dissolution in NaOH/urea aqueous solution at low temperature

AbstractCellulose can be dissolved in precooled (−12°C) 7 wt % NaOH/12 wt % urea aqueous solution within 2 min as a result of a dynamic self‐assembly process among solvent molecules (NaOH, urea, and water) and cellulose macromolecules. The dispersion condition of cellulose could play an important role on the formation of cellulose inclusion complex, leading to good dissolution (Cai et al., Macromolecules 2008, 41, 9345). Therefore, the stirring conditions on the cellulose dissolution in NaOH/urea were studied in this work. The results from solubility experiments, optical microscope images, and rheology experiments suggested that lager stirring blade area, longer stirring time, and higher stirring rate could improve the saturated solubility value (Cmax) of cellulose. However, when Cmax value reached a maximum, it changed hardly with further increasing stirring time and rates, which could be regarded as complete dissolution of cellulose in NaOH/urea. Moreover, a schematic diagram of the cellulose solubility had been made, as an instruction of cellulose dissolution in NaOH/urea. The DLS experiments displayed a similar rule. On the other hand, the Cmax values could be significantly enhanced by decreasing the stirring environment temperature, and the favorable environment temperature range was from −10 to −5°C. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Analysis of two main LNG CCS (cargo containment system) insulation boxes for leakage safety using experimentally defined thermal properties

Given that LNG cargo containment systems (CCS) operate in a range of environmental temperatures that includes cryogenic temperatures, thermal analysis should be carried out to determine their insulation capabilities. CCS components consist of various materials, and the temperature distribution of the CCS insulation box is the main concern. For this study an experiment was conducted to measure the thermal conductivity of insulation materials used in a LNG CCS under various temperature conditions ranging from room temperature to cryogenic temperature. Using the experimentally determined thermal properties a steady-state thermal analysis of a CCS insulation box was investigated. In addition a thermal analysis was conducted for the hull part of a carrier ship in a scenario in which LNG leaked through the secondary barrier of the insulation due to an accident. The safety of the hull was considered based on the ductile-to-brittle transition temperature of the hull.

Novel Methodology for the Estimation of Chemical Warfare Agent Mass Transport Dynamics. Part II: Absorption

A novel experimental and computational methodology has been developed for estimating Fickian mass transport parameters of organic molecules through stagnant mediums such as air, paints, or polymeric substrates. Dynamic contact angle experiments were performed to measure the droplet volume evolution with the chemical warfare agent bis(2-chloroethyl) sulfide (distilled mustard, known as the chemical warfare agent HD) on military-relevant substrates. A finite element model for simultaneous evaporation and absorption was used to analyze the experimental data and determine the mass transport parameter values of the agent in the absorptive material. The computational model was validated by comparison with the results of a complementary experimental technique involving testing for HD vapor emission from the contaminated material. The model predicted HD vapor emission rates from a silicone elastomer substrate for contamination conditions not directly tested. The simulation results show that the model parameters can be used to provide an accurate prediction of the absorbed mass and concentration distribution in the substrate at a range of environmental temperatures (20 to 50 °C) and contamination times (0 to infinite min). Predicting the absorbed mass in various substrate types and environmental conditions enables an accurate prediction of the resulting hazards from contaminated materials.

Metabolic and behavioural adaptations during early development of the Antarctic silverfish, Pleuragramma antarcticum

The Antarctic silverfish Pleuragramma antarcticum is a keystone species in the Ross Sea ecosystem, providing one of the major links between lower and higher trophic levels. Despite the importance of this species, surprisingly little is known of its early development and behaviour. Here, we determine the metabolic capacity of Pleuragramma embryonated eggs and larvae and make comparisons with developing stages of another notothenioid, the naked dragonfish Gymnodraco acuticeps. We also show that although large numbers of embryonated eggs of Pleuragramma are found floating among the platelet ice of Terra Nova Bay, they are able to sink prior to hatching in late spring, likely reducing the risk of exposure to the potentially lethal, ice-laden surface environment. Applying Stoke’s law, we determine the change in density required for embryonated eggs to sink at the measured rate and then consider possible mechanisms by which this might occur. Significantly, newly hatched larvae are positively gravitactic and negatively phototactic, such that their swimming behaviour also directs them away from the risk of freezing in the icy surface waters. Measurement of the acute thermal tolerance shows that Pleuragramma larvae have, on average, a sustainable swimming performance breadth of about 17°C, which is significantly greater than that of other adult notothenioids. Although it lacks significant antifreeze capacity in its early developmental stages, Pleuragramma has other attributes that may ensure survival over a wider range of environmental temperatures than other more stenothermal Antarctic notothenioids. How it might adapt to prolonged environmental change arising from phenomena such as global warming, however, requires further investigation.

The effects of different environmental conditions on thermoregulation and clinical and hematological variables in long-distance road-transported calves1

The aim of this study was to investigate the effects of long-distance road transport (19 h, from Poland to Italy) during 2 seasons (summer vs. winter) on clinical and hematological variables in calves. The environmental temperature range that could compromise the thermoregulation system (thermal stress) of the calves was tested. For the 7 Holstein calves in each transport, the BW and rectal temperature (RT) were measured, and blood samples were collected at the farm of origin, before loading at the transit center (T2), after unloading at the farm of destination (T3), and 1, 2, 3, and 4 d after arrival. The body temperature (BT) and heart rate (HR) were continuously monitored from T2 to T3. The data were statistically analyzed according to a mixed model that considered the fixed effects of transport (repeated measurements), season of journey, and their interaction. Within the observed temperature-humidity index (THI) range (30 to 80), effective thermoregulation allowed the calves to maintain their BT with small physiologic changes to prevent thermal stress, particularly in the summer. With no seasonal differences, the HR was greater at loading than unloading (120 vs. 115 beats per min; P = 0.012). As for the transport effect, the BW was less (P < 0.001) after unloading, and the RT was greater (P = 0.004). This effect was more marked in summer. The hematological variables indicated a moderate effect of transport on the hydration condition, reactive and muscular systems, and metabolism, although hematocrit (P = 0.004), erythrocytes, cortisol, NEFA, β-hydroxybutyrate, lactate, creatine kinase, lactate dehydrogenase, and aspartate aminotransferase activity (P < 0.001), and total protein (P = 0.007) were greater after unloading. This was confirmed by a moderate decrease in total leukocytes (P = 0.031) and glucose concentration (P = 0.002). The changes in the clinical variables were similar for both seasons even though in the summer, hematocrit (P < 0.001), urea (P = 0.008), and total protein (P = 0.010) increased and glucose concentration (P = 0.038) decreased. In conclusion, the data did not show a pronounced effect attributable to the season of the journey. Long-distance road transport leads to notable changes in clinical and hematological variables at the end of the journey. However, these variables remained within their physiological ranges and returned to basal values within a few days after the journey.

Surface Modification for Cotton Fiber and its Antimicrobial Characteristics

Quaternary ammonium compounds, Couple, Cotton fiber, Antibacterial activity. Abstract. a gemini-type quaternary ammonium compound with a hydroxyl group in their spacer chain, 4,5-bis(dodecyl dimethyl ammonium bromide)-1-pentanol (called as DAP12), was immobilized on the surface of cotton fiber by using a silane coupler, tetraethoxysilane and a novel antibacterial cotton fiber (called as CF12) was prepared. Antibacterial characteristics of CF12 were investigated comparatively with [3-(trimethoxysilyl) propyl] octadecyldimethylammonium chloride(TPOAC), a mono-type quaternary ammonium salt. CF12 had excellent antibacterial characteristics in the wide range of environmental pH and temperature, which is not weakened even if 30 times repetitive use. The experimental results indicated also that CF12 has higher antimicrobial activity than TPOAC immobilized on the surface of cotton fiber against a broad range of microorganisms, and average inhibition ratio against 15 strains of gram-negative, gram-positive bacteria and yeasts is 99.0% at 30 °C and pH 6.0.

The insensitivity of thermal preferences to various thermal gradient profiles in newts

Many ectotherms possess the ability to behaviourally regulate their body temperatures. Thermoregulatory behaviour is affected by various biotic and abiotic factors, which may cause a substantial bias in the laboratory estimates of preferred body temperatures (Tp). We examined thermoregulatory behaviour in alpine newts, Ichthyosaura (formerly Triturus) alpestris, in both horizontal linear and vertical nonlinear thermal gradients, to evaluate the influence of a disparate water temperature distribution on their thermal preferences. Newt positions in thermal gradients differed from those in constant temperatures, which indicates their thermal preferences in both experimental setups. The mean and range of body temperatures showed similar values in both types of aquatic thermal gradients. We concluded that under a sufficiently wide range of environmental temperatures, newt thermal preferences are largely insensitive to the thermal gradient profile. This supports the suitability of Tp estimates for further experimental and comparative studies in newts.

Thermal niche separation in two sympatric tropical intertidal Laternula (Bivalvia: Anomalodesmata)

Factors determining thermal niche separation of two sympatric infaunal bivalves ( Laternula truncata and L. boschasina) occurring in a Singapore mangrove were examined by comparing experienced microhabitat temperature with the thermal dependency of mortality and burrowing (both success and speed). The shallow burrowing L. boschasina, which experiences a wider range of environmental temperatures than the deeper burrowing L. truncata, can burrow over a wider temperature range (18.8–37.9 °C) than L. truncata (20.7–36.3 °C), a thermal window which corresponds closely to the maximum and minimum sediment temperatures predicted from the extreme air temperatures recorded in Singapore (22.1 to 35.7 °C for L. truncata and 18.8 to 38.5 °C for L. boschasina). The upper lethal limit of L. boschasina (36.4 to 38.4 °C) was also higher than that of L. truncata (33.5–35.5 °C), but the lower lethal limit of L. truncata (5.7–5.7 °C) was considerably lower than L. boschasina (18.1–20.4 °C) and microhabitat temperature. This apparent niche separation of lower limits was also mirrored in the speed of burrowing: L. boschasina maintained a constant burrowing speed across its temperature range, whilst L. truncata burrowed more slowly at low temperatures. The much greater predation pressure on the shallow burrowing L. boschasina may provide the selective pressure for the maintenance of activity at the expense of reduced survival at low temperatures.

Locusts use dynamic thermoregulatory behaviour to optimize nutritional outcomes

Because key nutritional processes differ in their thermal optima, ectotherms may use temperature selection to optimize performance in changing nutritional environments. Such behaviour would be especially advantageous to small terrestrial animals, which have low thermal inertia and often have access to a wide range of environmental temperatures over small distances. Using the locust, Locusta migratoria, we have demonstrated a direct link between nutritional state and thermoregulatory behaviour. When faced with chronic restrictions to the supply of nutrients, locusts selected increasingly lower temperatures within a gradient, thereby maximizing nutrient use efficiency at the cost of slower growth. Over the shorter term, when locusts were unable to find a meal in the normal course of ad libitum feeding, they immediately adjusted their thermoregulatory behaviour, selecting a lower temperature at which assimilation efficiency was maximal. Thus, locusts use fine scale patterns of movement and temperature selection to adjust for reduced nutrient supply and thereby ameliorate associated life-history consequences.

Influence of thermal boundary conditions on the dynamic behaviour of a rectangular single-phase natural circulation loop

Natural circulation of distilled water and FC43 has been experimentally investigated in a rectangular loop characterized by internal diameter of 30 mm and total length of 4.1 m. The aim of the present study is to analyse the influence of thermal boundary conditions on the flow regimes inside the pipes and on the stability of the system. The new aspect of the present research is the possibility of tuning the heat sink temperature in a range between −20 °C and +30 °C by means of a cryostat. This kind of analysis could be useful for the design of systems characterized by a wide range of environment temperatures, as for example for aerospatial applications. The other parameters investigated were the heat flux transferred to the fluid, which varied between 0.1 kW and 2.5 kW, and the thermo-physical properties of the working fluid. The system showed both stable and unstable behaviour. In particular, in the case of FC43 the loop was more unstable and it was characterized by higher velocities and frequencies compared to the case of distilled water. It was found that the stability threshold could be crossed by varying only the heat sink temperature, demonstrating the importance of this boundary condition on the dynamics of the system. Different flow regimes and fluid velocities were observed. In the case of steady-state flow, Vijayan’s correlation (Vijayan et al., 2000) was tested and found to give good agreement with experimental data. Linear stability analysis was made following the Vijayan’s model. In particular, the effect of heat sink temperature was considered in the dimensionless Stanton number based on the overall heat transfer coefficient at the heat sink. Finally, Ultrasound Pulsed Doppler Velocimeter (UPDV) was used on a natural circulation loop for the first time, and gave a preliminary validation of the traditional fluid velocity measurement method based on the frequency analysis.

NONUNIFORMITY CORRECTION FOR INFRARED FOCAL PLANE ARRAYS BASED ON ENVIRONMENTAL TEMPERATURE

Environmental influence on the signal output of infrared focal plane array(IRFPA) was analyzed.A nonuniformity correction(NUC) algorithm based on environmental and target temperatures was proposed.First,the original signal was captured by UL01011 staring infrared detector.Then,an exponential response model was established according to the principle of least square.Finally,nonuniformity was corrected by this model.Experimental results show that the proposed algorithm can give an exact response in a wider environmental temperature range and enhance effectively the precision of NUC.

Thermal Stability of Ammonia Borane: A Case Study for Exothermic Hydrogen Storage Materials

A model to determine the thermal stability of chemical hydrogen storage materials was developed to predict the stability of ammonia borane at 50−60 °C, the extreme range of environmental temperatures for hydrogen storage materials in PEM fuel cell applications. Experimental data from differential scanning calorimetry measurements between 70 and 85 °C were used to develop isothermal and adiabatic reactivity models that could be extrapolated down to temperatures of interest. Results of the analysis show that solid ammonia borane is metastable in the 50−60 °C range, having stability against appreciable reaction on the order of a week at 60 °C and months at 50 °C. An adiabatic analysis is the most extreme case, and stability of many days under such extreme conditions indicates that solid ammonia borane may be suited to most hydrogen storage applications. This type of analysis is also applicable to other candidate hydrogen storage materials.

Design concepts and verified performances in automotive HDD

Automotive HDD is required to have exceptionally higher reliability than mobile PC-use HDD. The design concepts and performance verifications of the third generation automotive HDDs with the last set of the LMR (Longitudinal Magnetic Recording) technologies and the fourth generation automotive HDDs with the first set of the PMR (Perpendicular Magnetic Recording) technologies are reported in detail. Both generations of automotive HDDs are already being applied to the automotive market at wider range of environmental temperature (-30 to 85 degree Celsius). Moreover it demonstrated that these products were able to function in the range of -43 to 107 degree Celsius without any bit-error-rate degradation. This paper should be the first to demonstrate the basic read/write performances of both LMR and PMR technology HDDs in this wide range of environmental temperature.

Using infrared thermography to assess seasonal trends in dorsal fin surface temperatures of free-swimming bottlenose dolphins (Tursiops truncatus) in Sarasota Bay, Florida

The temperature differential (ΔT) between a body surface and the environment influences an organism's heat balance. In Sarasota Bay, FL, where ambient water temperature (Tw) ranges annually from 11° to 33°C, ΔT was investigated in a resident community of bottlenose dolphins (Tursiops truncatus). Dorsal fin surface temperatures (Tdfin) were measured on wild, free-swimming dolphins using infrared thermography. Field and laboratory calibration studies were also undertaken to assess the efficacy of this non-invasive technology in the marine environment. The portability of infrared thermography permitted measurements of Tdfin across the entire range of environmental temperatures experienced by animals in this region. Results indicated a positive, linear relationship between Tdfin and Tw (r2= 0.978, P < 0.001). On average, Tdfin was 0.9°C warmer than Tw across seasons, despite the 22°C annual range in Tw. Changes in integumentary and vascular insulation likely account for the stability of ΔTdfin − w and the protection of core temperature (Tcore) across seasons. The high thermal conductivity of water may also influence this ΔT. The use of infrared thermography is an effective, non-invasive method of assessing dorsal fin skin surface temperatures (±1°C) across large numbers of wild, free-swimming dolphins throughout their thermally dynamic aquatic environment.

Body Temperature Variation During Nesting Forays in Midland Painted Turtles, Chrysemys picta marginata, in Michigan

During terrestrial nesting forays, north-temperate freshwater turtles may experience a range of environmental temperatures that could cause overheating or constrain movement if temperatures are too high or low. Yet, we have very little understanding of how body temperature (Tb) varies in freshwater turtles during various nesting foray activities. We studied Tb variation in Chrysemys picta marginata from a small marsh in northern Michigan, 2003–2004. Three individuals left the marsh, nested, and returned to the marsh in a single day; whereas, 5 others remained on land for up to 3 days, mostly immobile under leaf litter. While on land, Tb of turtles and air temperature (Ta) showed parallel, diel oscillations. Mean Tb of mobile turtles exceeded prevailing Ta values but was similar to Tb recorded for those same individuals while aquatic 1 week before and after the nesting foray. Therefore, active nesting turtles on forays may have maintained suitable Tb values by use of sun or shade. During the nesting process, Tb decreased from 23.5°C to 20.0°C. Turtles that entered terrestrial refugia after evening nesting had Tb values similar to those while mobile, often at times when the evening sky illuminated the nesting areas. Therefore, low light levels, which could limit navigation, and Tb values, which could impede movements, did not directly cause turtles to seek terrestrial refugia after nesting. Instead, we suggest that impending low environmental temperatures, waning light levels that would eventually impair navigation abilities, and, ultimately, the risk of predation while returning to the marsh caused turtles to seek terrestrial refugia.

A single-chip integrated interfacing circuit for wide-range resistive gas sensor arrays

In this work, we present novel experimental results on a single-chip integrated interface for wide-range resistive gas sensors. The proposed circuit has been proved to be able to reveal more than five decades of resistance variation (about 1% of relative error in the range 470 kΩ–50 GΩ) and, at the same time, to estimate the sensor parasitic capacitance (about 0.3 pF of estimation error in the range 0–33 pF). The fabricated integrated circuit has shown good performances in a wide range of environmental temperature (from −20 °C to 80 °C). The suitability for sensor applications has been proved by interfacing a high-value resistance MOX sensor and monitoring both the resistance and the parasitic capacitance values during a fast thermal transient of the sensor. Moreover, the front-end has been utilized, as an example, for the detection of hydrogen by means of a Figaro TGS 2600 sensor. An on/off modulation has been applied during the fluxing of two gas mixtures, constituted by both hydrogen and nitrogen, with a hydrogen concentration of 40 ppm and 80 ppm, respectively. Compared to other solutions presented in the literature, the implementation and fabrication as integrated circuit in a standard CMOS technology allows the whole interface to be considered as a simple and low-cost solution for wide-range resistive sensor arrays.