Wide Range Of Environmental Temperatures Research Articles

Effect of temperature on the mechanical behavior of pvc foams

Experiments were conducted to characterize the mechanical behavior of Divinycell PVC foams over a wide range of environmental temperatures, from −60 to +80°C. Transversely isotropic properties of the foams, including modulus, strength, and ductility, were found to vary with temperatures between the ductile-to-brittle transition temperature (−60 to −50°C) and just under the glass transition temperature (95 to 100°C). The elastic modulus and yield strength decreased linearly as the temperature increased from −60 to +80°C. Compressive strength also decreased steadily with increasing temperature over the entire temperature range. In contrast, tensile and shear strengths only showed a significant decrease in values as the temperature rose above 23°C (room temperature). Below 23°C, there was a minor change in tensile and shear strengths. Tensile and shear ductility decreased sharply as the temperature decreased from +80°C to −40°C and stabilized between −60 and −40°C, which is close to the ductile-to-brittle transition region. Fractography of the tensile and shear fracture surfaces confirmed brittle fracture at −60°C and ductile tearing at +60°C. Equations were derived to predict modulus, yield strength, compressive, tensile and shear strengths, and ductility at any temperature in terms of room temperature values.

Multi-scenario surface temperature estimation in lithium-ion batteries with transfer learning and LGT augmentation

The State of Temperature (SOT) plays a crucial role in ensuring the safety and reliability of lithium-ion batteries, as well as the stability of electric vehicles (Evs). Recently, data-driven methods for lithium-ion battery temperature estimation have often obtained short-term estimation information in a single scenario. To alleviate the above issues, this paper proposes a method for estimating the surface temperature of lithium-ion batteries based on Local and Global Trend (LGT) data augmentation and Long Short-Term Memory (LSTM) model transfer. Initially, voltage and current data are processed using two types of filtering methods to reduce noise while preserving the fluctuating characteristics of the original data. Differential features are subsequently extracted from the polynomially filtered curves. Then all the data, including the filtered data and the features are fed into the LGT data augmentation algorithm, followed by the use of an LSTM transferable model to estimate the surface temperature of the target battery. Furthermore, the method is tested on both laboratory datasets and datasets with real driving conditions, covering a wide range of environmental temperatures and driving scenarios typical of EVs. The experimental results demonstrate that retraining with only the first 30 % of the target battery's data yields effective SOT estimation results.

The kainate receptor GluK2 mediates cold sensing in mice.

Thermosensors expressed in peripheral somatosensory neurons sense a wide range of environmental temperatures. While thermosensors detecting cool, warm and hot temperatures have all been extensively characterized, little is known about those sensing cold temperatures. Though several candidate cold sensors have been proposed, none has been demonstrated to mediate cold sensing in somatosensory neurons in vivo, leaving a knowledge gap in thermosensation. Here we characterized mice lacking the kainate-type glutamate receptor GluK2, a mammalian homolog of the Caenorhabditis elegans cold sensor GLR-3. While GluK2 knockout mice respond normally to heat and mechanical stimuli, they exhibit a specific deficit in sensing cold but not cool temperatures. Further analysis supports a key role for GluK2 in sensing cold temperatures in somatosensory DRG neurons in the periphery. Our results reveal that GluK2-a glutamate-sensing chemoreceptor mediating synaptic transmission in the central nervous system-is co-opted as a cold-sensing thermoreceptor in the periphery.

Alternative CO2-based blends for transcritical refrigeration systems

The extensive use of CO2 in commercial refrigeration system has grown in the last two decade thanks to the development of new components and configurations that allows working in transcritical conditions efficiently. However, using these arrangements increases the cost and complexity of the refrigerating plant, making it challenging to implement them in medium or low-capacity systems. As an alternative, CO2-based binary mixtures report attractive improvements that allow for enhancing the COP of the system by minimising its complexity and maintaining the safety and environmental conditions of CO2. This manuscript analyses five binary mixtures of CO2 with the refrigerants R32, R152a, R1234yf, R1234ze(E) and R1270, determining the optimal mixture composition for maximising the COP of a CO2 transcritical refrigeration plant in a wide range of environmental temperatures (0 to 40°C). Fixing the operating conditions for a medium-temperature application, the binary mixtures of CO2/R32 (81/19% in mass) and CO2/R1270 (92.5/7.5% in mass) reported the best COP enhancements results with increments up to +21.4% and +8.7%, respectively, at high environmental temperatures.

Temperature-tolerant flexible supercapacitor integrated with a strain sensor using an organohydrogel for wearable electronics

Due to the increased demand for wearable devices, there has been extensive research on flexible energy storage devices (e.g., batteries and supercapacitors) and bio-signal monitoring sensors. For the practical application of wearable devices, stable operation regardless of the environmental temperature is required. In this study, we report a temperature-tolerant flexible supercapacitor based on a synthesized novel organohydrogel electrolyte designed to power an integrated strain sensor for the monitoring of bio-signals. The fabricated supercapacitor exhibits a remarkable gravimetric capacitance of 123.4F g−1, 147.0F g−1, and 156.2F g−1 at temperatures of − 20 °C, 25 °C, and 80 °C, respectively. After three repetitive cycles shifting from − 20 °C to 80 °C, the initial capacitance is almost fully recovered. In addition, after 1000 cycles of bending deformation, the capacitance remains almost the same, thus verifying the flexibility of the device. A strain sensor fabricated using the same organohydrogel exhibits a change in resistance with stretching deformation, with a gauge factor of 1.77, 1.61, and 1.50 at 25 °C, −20 °C, and 80 °C. By vertically integrating the supercapacitor and strain sensor, various bio-signals, including finger bending and swallowing are successfully detected using the stored energy of the supercapacitor. As a whole, the results highlight the potential of our proposed temperature-tolerant flexible device fabricated based on a single organohydrogel for use in wearable applications that are stable over a wide range of environmental temperatures.

Characterization of Chromatin Remodeling Genes Involved in Thermal Tolerance of Biologically Invasive Bemisia tabaci.

As an invasive species, Bemisia tabaci Mediterranean (MED) has notable potential to adapt to a wide range of environmental temperatures, which enables it to successfully spread after invasion and occupy habitats over a wide latitude range. It has been postulated that chromatin remodeling mechanisms are related to the rapid acquisition of adaptive traits and thermal resistance in invasive species; however, relevant experimental evidence is scarce. To identify the molecular characteristics and assess the role of chromatin remodelers in thermal stress within invasive MED and native Asia II 1 of the B. tabaci species complex, we identified 13 switching defective/sucrose non-fermenting (SWI/SNF) and 10 imitation switch (ISWI) family members in the B. tabaci genome, analyzed their molecular characteristics and structures, and identified key mutation sites between MED and Asia II 1, then cloned the catalytic subunits, and revealed the difference in thermal tolerance function. The results showed that the expression levels of Bt-BRM-1 and Bt-BRM-2 were significantly higher in MED than in Asia II 1 during heat stress, and Bt-BRM-2 expression was significantly higher during cold stress. In addition, RNA interference results indicated that the two target genes had similar temperature tolerance function in the both two cryptic species. This study is the first to identify and analyze the molecular characteristics of SWI/SNF and ISWI family members and reveal their potential key roles in temperature tolerance in poikilothermic ectotherms. The results will assist in understanding the underlying temperature adaptation mechanism of invasive insects and will enrich stress adaptation research systems from an epigenetic perspective.

The metabolism and swimming performance of sheepshead minnows (Cyprinodon variegatus) following thermal acclimation or acute thermal exposure.

Ectothermic animals are especially susceptible to temperature change, considering that their metabolism and core temperature are linked to the environmental temperature. As global water temperatures continue to increase, so does the need to understand the capacity of organisms to tolerate change. Sheepshead minnows (Cyprinodon variegatus) are the most eurythermic fish species known to date and can tolerate a wide range of environmental temperatures from - 1.9 to 43.0°C. But little is known about the physiological adjustments that occur when these fish are subjected to acute thermal challenges and long-term thermal acclimation. Minnows were acclimated to 10, 21, or 32°C for 4weeks or acutely exposed to 10 and 32°C and then assessed for swimming performance [maximum sustained swimming velocity (Ucrit), optimum swimming velocity (Uopt)] and metabolic endpoints (extrapolated standard and maximum metabolic rate [SMR, MMR), absolute aerobic scope (AS), and cost of transport (COT)]. Our findings show that the duration of thermal exposure (acute vs. acclimation) did not influence swimming performance. Rather, swimming performance was influenced by the exposure temperature. Swimming performance was statistically similar in fish exposed to 21 or 32°C (approximately 7.0 BL s-1), but was drastically reduced in fish exposed to 10°C (approximately 2.0 BL s-1), resulting in a left-skewed performance curve. There was no difference in metabolic end points between fish acutely exposed or acclimated to 10°C. However, a different pattern was observed in fish exposed to 32°C. MMR was similar between acutely exposed or acclimated fish, but acclimated fish had a 50% reduction in extrapolated SMR, which increased AS by 25%. However, this enhanced AS was not associated with changes in swimming performance, which opposes the oxygen-capacity limited thermal tolerance concept. Our findings suggest that sheepshead minnows may utilize two distinct acclimation strategies, resulting in different swimming performance and metabolic patterns observed between 10 and 32°C exposures.

Effects of temperature on larval development, alkaloid production and microsporidiosis in the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae)

Nosema adaliae, a microsporidian pathogen described from the two-spotted lady beetle, Adalia bipunctata L., delays larval development when A. bipunctata is reared under laboratory conditions at 25 °C. In nature, lady beetles often experience a wide range of environmental temperatures, but little is known regarding the effects of microsporidian pathogens on lady beetles when they are reared at higher and lower temperatures. In this study, the effects of elevated rearing temperatures and microsporidiosis were observed on larval development time and mortality, sex ratios, alkaloid content (adaline and adalinine), and adult morphometrics. Uninfected larvae (24 h-old) were provided either an uninfected or N. adaliae-infected conspecific egg and subsequently reared at three temperatures (25 °C, 27.5 °C or 30 °C). After the egg was eaten, larvae were provided a diet of green peach aphids and their development was recorded daily. Following eclosion, a subsample of adults were photographed for microscopic measurements and reflex-fluid was collected for alkaloid analysis using gas chromatography-mass spectrometry. Afterwards, all individuals were examined to determine the number that had become infected, and the same subsample was used to assess the severity of infection. Development time was delayed significantly for larvae that consumed a N. adaliae-infected egg, and infected larvae took significantly longer to develop at 25 °C than at 27.5 °C or 30 °C. No differences were observed for larval mortality or sex ratios. The relative proportion of adaline increased when larvae were reared at 30 °C, but adaline concentration was not affected by the pathogen, N. adaliae. Adults reared at 25 °C had larger body measurements when compared to those reared at 27.5 °C and 30 °C. Overall, adults that had eaten a N. adaliae-infected A. bipunctata egg as larvae had similar body measurements to those that ate an uninfected egg. When comparing male and female measurements, a significant interaction between infection status, temperature and sex was observed for elytra length and head capsule width only. These measurements were similar for uninfected and N. adaliae-infected females across all temperatures. However, when reared at 25 °C, uninfected males had significantly smaller elytra and head capsules than did infected males; but when reared at 30 °C, no significant difference was observed for these measurements. Both percent infection and average spore count decreased at 27.5 °C and 30 °C. These results suggest that temperatures above 25 °C have a mitigating effect against N. adaliae in A. bipunctata.

Heat-Bath Algorithmic Cooling with optimal thermalization strategies

Heat-Bath Algorithmic Cooling is a set of techniques for producing highly pure quantum systems by utilizing a surrounding heat-bath and unitary interactions. These techniques originally used the thermal environment only to fully thermalize ancillas at the environment temperature. Here we extend HBAC protocols by optimizing over the thermalization strategy. We find, for any d-dimensional system in an arbitrary initial state, provably optimal cooling protocols with surprisingly simple structure and exponential convergence to the ground state. Compared to the standard ones, these schemes can use fewer or no ancillas and exploit memory effects to enhance cooling. We verify that the optimal protocols are robusts to various deviations from the ideal scenario. For a single target qubit, the optimal protocol can be well approximated with a Jaynes-Cummings interaction between the system and a single thermal bosonic mode for a wide range of environmental temperatures. This admits an experimental implementation close to the setup of a micromaser, with a performance competitive with leading proposals in the literature. The proposed protocol provides an experimental setup that illustrates how non-Markovianity can be harnessed to improve cooling. On the technical side we 1. introduce a new class of states called maximallyactivestates and discuss their thermodynamic significance in terms of optimal unitary control, 2. introduce a new set of thermodynamic processes, called β-permutations, whose access is sufficient to simulate a generic thermalization process, 3. show how to use abstract toolbox developed within the resource theory approach to thermodynamics to perform challenging optimizations, while combining it with open quantum system dynamics tools to approximate optimal solutions within physically realistic setups.

State of charge estimation based on a thermal coupling simplified first-principles model for lithium-ion batteries

Accurate lithium-ion battery state of charge (SOC) estimation can enhance reliable and safe operation of electric vehicles. A thermal coupling simplified first-principles model has been adopted to achieve high SOC estimation accuracy. Extended Kalman filter and adaptive extended Kalman filter algorithms are separately combined with the model to estimate state of charge for a wide range of environmental temperatures (10–45 °C) and different charge/discharge rates. The SOC estimation method is validated with respect to the accuracy and convergence. The average absolute errors using the adaptive extended Kalman filter algorithm under conditions of dynamic stress tests and hybrid pulse power characteristics are less than 1%, which is 1.5% smaller than that of the EKF algorithm. Compared to the extended Kalman filter algorithm, the adaptive extended Kalman filter algorithm can achieve fast convergence after less than 10 s while maintaining the estimation accuracy given an initial SOC guess error of 50%. The effects of sampling frequency and battery aging states on estimation accuracy are also assessed. A sampling frequency of at least 1 Hz can ensure the accuracy is within 1%. The developed SOC estimation method is also fit for the degraded battery with about 1% estimation error.

Bioinspired Design of Vascular Artificial Muscle

AbstractRecently, liquid crystal elastomers (LCEs) have drawn much attention for its wide applications as artificial muscle in soft robotics, wearable devices, and biomedical engineering. One commonly adopted way to trigger deformation of LCEs is using embedded heating elements such as resistance heating wires and photothermal particles. To enable the material to recover to its unactuated state, passive and external cooling is often employed to lower the temperature, which is typically slow and environmentally sensitive. The slow and uncontrollable recovery speed of thermally driven artificial muscle often limits its applications when even moderate cyclic actuation rate is required. In this article, inspired by biology, a vascular LCE‐based artificial muscle (VLAM) is designed and fabricated with internal fluidic channel in which the hot or cool water is injected to heat up or cool down the material to achieve fast actuation as well as recovery. It is demonstrated that the actuation stress, strain, and cyclic response rate of the VLAM are comparable to mammalian skeletal muscle. Because of the internal heating and cooling mechanism, VLAM shows a very robust actuating performance within a wide range of environmental temperatures. The VLAM designed in this article may also provide a convenient way to harvest waste heat to conduct mechanical work.

Zebrafish as a model of mammalian cardiac function: Optically mapping the interplay of temperature and rate on voltage and calcium dynamics

The zebrafish (Danio rerio) heart is a viable model of mammalian cardiovascular function due to similarities in heart rate, ultrastructure, and action potential morphology. Zebrafish are able to tolerate a wide range of naturally occurring temperatures through altering chronotropic and inotropic properties of the heart. Optical mapping of cannulated zebrafish hearts can be used to assess the effect of temperature on excitation-contraction (EC) coupling and to explore the mechanisms underlying voltage (Vm) and calcium (Ca2+) transients.Applicability of zebrafish as a model of mammalian cardiac physiology should be understood in the context of numerous subtle differences in structure, ion channel expression, and Ca2+ handling. In contrast to mammalian systems, Ca2+ release from the sarcoplasmic reticulum (SR) plays a relatively small role in activating the contractile apparatus in teleosts, which may contribute to differences in restitution. The contractile function of the zebrafish heart is closely tied to extracellular Ca2+ which enters cardiomyocytes through L-type Ca2+ channel (LTCC), T-type Ca2+ channel (TTCC), and the sodium-calcium exchanger (NCX).Novel data found that despite large temperature effects on heart rate, Vm, and Ca2+ durations, the relationship between Vm and Ca2+ signals was only minimally altered in the face of acute temperature change. This suggests that zebrafish Vm and Ca2+ kinetics are largely rate-independent. In comparison to mammalian systems, zebrafish Ca2+ cycling is inherently more dependent on transsarcolemmal Ca2+ transport and less reliant on SR Ca2+ release. However, the compensatory actions of various components of the Ca2+ cycling machinery of the zebrafish cardiomyocytes, allow for maintenance of EC coupling over a wide range of environmental temperatures.

Origin, differentiation and functional ultrastructure of egg envelopes in the cestode Echinococcus multilocularis Leuckart, 1863 (Cyclophyllidea: Taeniidae)

The origin, differentiation and functional ultrastructure of oncospheral or egg envelopes in Echinococcus multilocularis Leuckart, 1863 were studied by transmission electron microscopy (TEM) and cytochemistry. The purpose of our study is to describe the formation of the four primary embryonic envelopes, namely vitelline capsule, outer envelope, inner envelope and oncospheral membrane, and their transformation into the oncospheral or egg envelopes surrounding the mature hexacanth. This transformation takes place in the preoncospheral phase of embryonic development. The vitelline capsule and oncospheral membrane are thin membranes, while the outer and inner envelopes are thick cytoplasmic layers formed by two specific types of blastomeres: the outer envelope by cytoplasmic fusion of two macromeres and the inner envelope by cytoplasmic fusion of three mesomeres. Both outer and inner envelopes are therefore cellular in origin and syncytial in nature. During the advanced phase of embryonic development, the outer and inner envelopes undergo great modifications. The outer envelope remains as a metabolically active layer involved in the storage of glycogen and lipids for the final stages of egg development and survival. The inner envelope is the most important protective layer because of its thick layer of embryophoric blocks that assures oncospheral protection and survival. This embryophore is the principal layer of mature eggs, affording physical and physiological protection for the differentiated embryo or oncosphere, since the outer envelope is stripped from the egg before it is liberated. The embryophore is very thick and impermeable, consisting of polygonal blocks of an inert keratin-like protein held together by a cementing substance. The embryophore therefore assures extreme resistance of eggs, enabling them to withstand a wide range of environmental temperatures and physicochemical conditions.

Effect of thermal stress on metabolic and oxidative stress biomarkers of Hoplosternum littorale (Teleostei, Callichthyidae)

The present study aimed to investigate in Hoplosternum littorale (Hancock, 1828) the effects of different water temperatures (10°C, 25°C-control group- and 33°C) on physiologic and metabolic traits following acute (1day) and chronic (21days) exposures. We analyzed several biomarker responses in order to achieve a comprehensive survey of fish physiology and metabolism under the effect of this natural stressor. We measured morphological indices, biochemical and hematological parameters as well as oxidative stress markers. To evaluate energy consumption, muscle and hepatic total lipid, protein and glycogen concentrations were also quantified. Extreme temperatures exposures clearly resulted in metabolic adjustments, being liver energy reserves and plasma metabolites the most sensitive parameters detecting those changes. We observed reduced hepatosomatic index after acute and chronic exposure to 33°C while glycogen levels decreased at both temperatures and time of exposure tested. Additionally, acute and chronic exposures to 10°C increased liver lipid content and plasma triglycerides. Total protein concentration was higher in liver and lower in plasma after chronic exposures to 10°C and 33°C. Acute exposition at both temperatures caused significant changes in antioxidant enzymes tested in the different tissues without oxidative damage to lipids. Antioxidant defenses in fish failed to protect them when they were exposed for 21days to 10°C, promoting higher lipid peroxidation in liver, kidney and gills. According to multivariate analysis, oxidative stress and metabolic biomarkers clearly differentiated fish exposed chronically to 10°C. Taken together, these results demonstrated that cold exposure was more stressful for H. littorale than heat stress. However, this species could cope with variations in temperature, allowing physiological processes and biochemical reactions to proceed efficiently at different temperatures and times of exposure. Our study showed the ability of H. littorale to resist a wide range of environmental temperatures and contributes for the understanding of how this species is adapted to environments with highly variable physicochemical conditions.

Avian thermoregulation in the heat: evaporative cooling capacity of arid-zone Caprimulgiformes from two continents.

Birds in the order Caprimulgiformes (nightjars and allies) have a remarkable capacity for thermoregulation over a wide range of environmental temperatures, exhibiting pronounced heterothermy in cool conditions and extreme heat tolerance at high environmental temperatures. We measured thermoregulatory responses to acute heat stress in three species of Caprimulgiformes that nest in areas of extreme heat and aridity, the common poorwill (Phalaenoptilus nuttallii: Caprimulgidae) and lesser nighthawk (Chordeiles acutipennis: Caprimulgidae) in the Sonoran Desert of Arizona, and the Australian owlet-nightjar (Aegotheles cristatus: Aegothelidae) in the mallee woodlands of South Australia. We exposed wild-caught birds to progressively increasing air temperatures (Ta) and measured resting metabolic rate (RMR), evaporative water loss (EWL), body temperature (Tb) and heat tolerance limit (HTL; the maximum Ta reached). Comparatively low RMR values were observed in all species (0.35, 0.36 and 0.40 W for the poorwill, nighthawk and owlet-nightjar, respectively), with Tb approximating Ta at 40°C and mild hyperthermia occurring as Ta reached the HTL. Nighthawks and poorwills reached HTLs of 60 and 62°C, respectively, whereas the owlet-nightjar had a HTL of 52°C. RMR increased gradually above minima at Ta of 42, 42 and 35°C, and reached 1.7, 1.9 and 2.0 times minimum resting values at HTLs in the poorwill, nighthawk and owlet-nightjar, respectively. EWL increased rapidly and linearly as Ta exceeded Tb and resulted in maximum rates of evaporative heat dissipation equivalent to 237-424% of metabolic heat production. Bouts of gular flutter resulted in large transient increases in evaporative heat loss (50-123%) accompanied by only small increments in RMR (<5%). The cavity-nesting/roosting owlet-nightjar had a lower HTL and less efficient evaporative cooling compared with the species that nest and/or roost on open desert surfaces. The high efficiency of gular flutter for evaporative cooling, combined with mild hyperthermia, provides the physiological basis for defending Tb well below Ta in extreme heat and is comparable to the efficient cooling observed in arid-zone columbids in which cutaneous EWL is the predominant cooling pathway.

Structural and functional characteristics of photosynthetic apparatus of chlorophyll-containing grape vine tissue

Photosynthesis in tissues under periderm of woody stems and shoots of perennial plants occurs in environment that is very different from the internal environment of leaf chloroplasts. These tissues are characterized by high CO2 and low O2 concentrations, more acidic surroundings, besides that only light which have passed through periderm reaches photosynthetic antennas. In contrast to leaves of deciduous plants chlorenchyma tissues of wintering plant organs are exposed to temperature fluctuations during all seasons, that is why the photosynthetic apparatus of woody stems has to be able to adapt to a wide range of environmental temperatures. In order to reveal unique features, which enable photosynthetic apparatus of chlorenchyma cells in woody plant organs to implement biological functions under different light and temperature conditions, we studied photosynthetic tissues of stem cortex in grapevine (Vitis vinifera L.) under normal conditions and after exposure to suboptimal temperatures and high light intensity. Comparative analysis of photosynthetic pigment composition and low-temperature chlorophyll fluorescence emission spectrum of leaves, young shoots and chlorenchyma of lignified shoots revealed relatively high level of chlorophyll b and carotenoids, and high photosystem II (PSII) to photosystem I (PSI) ratio in woody shoots. Analysis of parameters of variable chlorophyll fluorescence revealed high PSII activity in grapevine shoot cortex and demonstrated improved freeze tolerance and higher sensitivity to light of photosynthetic apparatus in grape vine in comparison to leaves. It was shown for the first time that photosynthetic apparatus in chlorenchyma cells of vine undergoes so-called “state-transition”–fast rearrangements leading to redistribution of energy between photosystems. Analysis of fatty acid (FA) compositions of lipids in examined tissues showed that the FA unsaturation index in green tissue of vine is lower than in leaves. A distinct feature of FA compositions of lipids in vine cortex was relatively high level of linoleic acid.

Effect of sublethal temperatures on pulsed light inactivation of bacteria

Abstract This study investigated the effect of sublethal temperatures on the efficacy of pulsed light (PL) treatment for the inactivation of Listeria innocua, Escherichia coli ATCC 25922, and Pseudomonas fluorescens. A thin layer of clear, liquid phosphate buffer inoculated with one of the challenge organisms, at a concentration of about 108 CFU/mL, was equilibrated to a temperature ranging from 5 °C to 50 °C and then treated with PL, at doses between 1.02 and 12.29 J/cm2. All treatments were performed in triplicate. In the temperature range of 5 °C to 40 °C, the average maximum reductions for L. innocua, E. coli, P. fluorescens were 6.27 ± 0.23 log CFU, 6.66 ± 0.36 log CFU, and 6.15 ± 0.19 log CFU, respectively. Temperature did not affect PL inactivation of E. coli or P. fluorescens, but a modest synergistic effect between PL and temperature was observed for L. innocua treated above 40 °C. Industrial relevance This study suggests that PL inactivation of bacteria is independent of temperature in the sublethal range 5 °C to 40 °C. The practical benefit of this finding is that PL treatments can be conducted in a wide range of environmental temperatures, without any change in the outcome of the treatment.

Design of carbon/epoxy–aluminum hybrid upper arm of the pantograph of high-speed trains using adhesive bonding technique

The upper arm of a steel pantograph was replaced by a high stiffness carbon/epoxy composite–aluminum hybrid structure to enhance the mechanical performance of a pantograph for high-speed trains. By considering driving conditions such as high voltage discharge and a wide range of environmental temperatures, the composite laminates were applied to the inner surface of an aluminum pipe by using adhesive bonding with an epoxy adhesive. The bending stiffness of the slender arm structure was the most important mechanical performance criterion; therefore, only simple stacking sequences ([0]10T, [±5]5T, [±10]5T), which guarantee the higher bending stiffness, were tried to determine the mechanical performance such as maximum deflection and natural frequency. Thermal stress due to environmental temperature (−35°C to 65°C) was also evaluated by finite element analysis. The generated stresses in the bonding layers were closely investigated, and it was found that the maximum stress was below 60% of the material strength of the epoxy adhesive under various temperature conditions.

Modeling and analysis of hydraulic dashpot for impact free operation in a shut-off rod drive mechanism

Rotary hydraulic dashpot used for shut-off rod drive mechanism application of a nuclear reactor has been studied in this paper for impact free operation. The rotary hydraulic dashpot has been modeled as a system with 1 degree of freedom (DOF) and the simulation results are experimentally validated. The dashpot is modeled as a hinge joint with moving and fixed vanes as rigid bodies. Shut-off rods are used to shut-down a nuclear reactor and hydraulic dashpot absorbs the energy of freely falling shut-off rod at the end of rod travel. With the increase in the environmental temperature the dashpot becomes underdamped at a point because of reduction in the viscosity of oil and results into impact on mechanism components. Hydraulic dashpot designs are finalized with an optimum combination of dashpot clearances and oil viscosity to meet the drop time criterion and impact free operation at room temperature as well as at elevated temperature. Also with the change in mechanical loads the dashpot becomes underdamped. So the study is further extended to see the effects of various parameters such as moment of inertia, constraint angle and applied moment on the dashpot. Study is focused on obtaining dashpot responses in terms of relative rotation, relative angular velocity and relative angular acceleration at various environmental temperatures. Finite element commercial code COMSOL Multiphysics 5.1 has been used for numerical simulations. Equations for both rigid body dynamics and heat transfer in solids are solved simultaneously. Thus, energy absorbed and local temperature rise in the dashpot operation is also obtained. Both simulation and experimental results at wide range of environmental temperature are presented and compared in this paper. This study forms a good tool to design a hydraulic dashpot, which gives impact free operation in a shut-off rod free fall.

Characterization of the transcriptome and temperature-induced differential gene expression in QPX, the thraustochytrid parasite of hard clams.

BackgroundThe hard clam or northern quahog, Mercenaria mercenaria, is one of the most valuable seafood products in the United States representing the first marine resource in some Northeastern states. Severe episodes of hard clam mortality have been consistently associated with infections caused by a thraustochytrid parasite called Quahog Parasite Unknown (QPX). QPX is considered as a cold/temperate water organism since the disease occurs only in the coastal waters of the northwestern Atlantic Ocean from Maritime Canada to Virginia. High disease development at cold temperatures was also confirmed in laboratory studies and is thought to be caused predominantly by immunosuppression of the clam host even though the effect of temperature on QPX virulence has not been fully investigated. In this study, the QPX transcriptome was sequenced using Roche 454 technology to better characterize this microbe and initiate research on the molecular basis of QPX virulence towards hard clams.ResultsClose to 18,000 transcriptomic sequences were generated and functionally annotated. Results revealed a wide array of QPX putative virulence factors including a variety of peptidases, antioxidant enzymes, and proteins involved in extracellular mucus production and other secretory proteins potentially involved in interactions with the clam host. Furthermore, a 15 K oligonucleotide array was constructed and used to investigate the effect of temperature on QPX fitness and virulence factors. Results identified a set of QPX molecular chaperones that could explain its adaptation to cold temperatures. Finally, several virulence-related factors were up-regulated at low temperature providing molecular targets for further investigations of increased QPX pathogenicity in cold water conditions.ConclusionsThis is one of the first studies to characterize the transcriptome of a parasitic labyrinthulid, offering new insights into the molecular bases of the pathogenicity of members of this group. Results from the oligoarray study demonstrated the ability of QPX to cope with a wide range of environmental temperatures, including those considered to be suboptimal for clam immunity (low temperature) providing a mechanistic scenario for disease distribution in the field and for high disease prevalence and intensity at low temperature. These results will serve as basis for studies aimed at a better characterization of specific putative virulence factors.