Increase In External Temperature Research Articles

Elevated external temperature affects cell ultrastructure and heat shock proteins (HSPs) in Paramacrobiotus experimentalis Kaczmarek, Mioduchowska, Poprawa, & Roszkowska, 2020

Increasing temperature influences the habitats of various organisms, including microscopic invertebrates. To gain insight into temperature-dependent changes in tardigrades, we isolated storage cells exposed to various temperatures and conducted biochemical and ultrastructural analysis in active and tun-state Paramacrobiotus experimentalis Kaczmarek, Mioduchowska, Poprawa, & Roszkowska, 2020. The abundance of heat shock proteins (HSPs) and ultrastructure of the storage cells were examined at different temperatures (20 °C, 30 °C, 35 °C, 37 °C, 40 °C, and 42 °C) in storage cells isolated from active specimens of Pam. experimentalis. In the active animals, upon increase in external temperature, we observed an increase in the levels of HSPs (HSP27, HSP60, and HSP70). Furthermore, the number of ultrastructural changes in storage cells increased with increasing temperature. Cellular organelles, such as mitochondria and the rough endoplasmic reticulum, gradually degenerated. At 42 °C, cell death occurred by necrosis. Apart from the higher electron density of the karyoplasm and the accumulation of electron-dense material in some mitochondria (at 42 °C), almost no changes were observed in the ultrastructure of tun storage cells exposed to different temperatures. We concluded that desiccated (tun-state) are resistant to high temperatures, but not active tardigrades (survival rates of tuns after 24 h of rehydration: 93.3% at 20 °C, 60.0% at 35 °C, 33.3% at 37 °C, 33.3% at 40 °C, and 20.0% at 42 °C).

Biaxial fatigue failure of short glass fiber reinforced polyamide 6,6: An in-depth investigation of stiffness drop and microstructural evolution

In the automotive industry, short glass fiber-reinforced thermoplastics are widely used under the hood and subjected to dynamic vibrations of the engine in multiple directions resulting in fatigue failure. Under fatigue loading, a significant portion of the strain energy is stored within the material, while the remaining portion is lost due to internal frictions and the damage occurrence. Internal friction results in heat generation, which in turn causes an increase in external temperature. This increase in temperature leads to thermal degradation of the polymer. Investigations on the cause of the stiffness drop are not widely available in the literature. Therefore, this study explores the source of the stiffness drop under biaxial fatigue loading of a polyamide 6,6 reinforced with 30 wt. % short glass fibers (PA66GF30) and distinguishes the contributions of thermal degradation and damage accumulation. The thermal evolution of the specimens was captured by means of thermography. In addition, the digital image correlation (DIC) technique was used to measure the in situ strain field during the fatigue. Despite the temperature stabilization being observed around the 10,000th cycle, the reduction in the stiffness continued until failure which was attributed to the mechanical damage accumulation and cyclic creep during the fatigue tests. Dynamic mechanical analyses (DMA) were carried out to quantify the stiffness drop with the varying temperature. From the results, it is seen that the damage accumulation and cyclic creep during the fatigue tests were responsible for the major part of the stiffness drop. Finally, scanning electron microscopy (SEM) inspection of the fracture surface was performed to identify fatigue damage mechanisms. Four unique features associated with the fatigue damage were identified: (1) debonding of fibers from the matrix, (2) polymer matrix crazing, and (3) cavitation and porosities, (4) pull out fiber ends and break on the fiber.

Study of the Relationship Between Temperature Change and Energy Transfer in Thermodynamic Processes in Buildings

In this paper, the relationship between room temperature and outside temperature, wall temperature, system operation, and energy consumption is investigated through mathematical modeling and simulation experiments. The thermodynamic parameters of a typical room are used in the study, and the characteristics of the heating and cooling system are considered. 1. This paper analyses the variation of room temperature, wall temperature, switching state, and heating power with time. The results show that the room and wall temperatures are influenced by the external temperature and system operation, while the switching state and heating power are regulated by the room temperature. The correlation between temperature and heating power is quantified by calculating the correlation coefficient matrix. The results show that there is a positive correlation between room temperature and heating power, while there is a negative correlation between wall temperature and room temperature and heating power. 2. This paper investigates the effect of external temperature on room temperature and wall temperature. The results show that an increase in external temperature leads to a decrease in room temperature and wall temperature. In addition, it is found that the indoor temperature is more sensitive to changes in external temperature within the range of changes in external temperature. 3. It is based on the steady-state solution curves between temperature and external temperature, as well as thermodynamic plots of system operation and energy consumption. The visual presentation of the effect of external temperature on the system provides a reference for optimizing building energy use and designing efficient heating and cooling systems. This study provides insight into the relationship between temperature change and energy transfer in building thermodynamic processes, guiding for achieving sustainable energy utilization and reducing environmental impacts. It is of great significance for optimizing the design of building energy systems and improving the efficiency of energy use.

Influence of age and seasonality on boar seminal plasma steroids quantification: A preliminary study.

Seasonal changes, especially temperature and photoperiod, are well-known determining factors of swine reproductive capacity, but the underlying mechanisms remain unknown. This study aimed to investigate the effect of age and seasonal variations on boar seminal plasma steroids (dehydroepiandrosterone [DHEA], cortisol [CORT], and testosterone [TEST]) over 1 year. Four commercial hybrid adult boars (Large White × Duroc), aged between 12 and 44 months, were repeatedly evaluated at the Department of Veterinary Medical Sciences of the University of Bologna. Daily temperature and light hours relating to the collection date were considered for each observation within the four astronomical seasons: Winter, spring, summer, and autumn. Hormones were quantified using radioimmunoassay. The association between seasonal factors and hormone concentrations was evaluated using linear regression models. Univariate models were estimated for each hormone to assess the influence of the independent variables; two multivariate models were assessed to evaluate the effect of temperature and daylight hours, including boar and season factors. Age significantly affected all analyzed hormones (CORT p < 0.0001; DHEA p < 0.0001; and TEST p < 0.0001). The highest average levels were found for each hormone during summertime, suggesting a positive correlation between steroid concentrations with temperature and light hours. The results of this study support the hypothesis that the increase in external temperature and light hours is somehow associated with higher levels of steroid concentrations in the seminal plasma of in-housed boars. These findings may help further investigate seasonal fluctuations in reproductive outcomes, which are well-known for porcine species.

Decisive Factors in the Sequential Thermal Decomposition Reactions of Ni-Based Layered Cathode Materials

Understanding thermal behaviors of energy storage materials according to the charged states is essential to uncover the key factors for improving thermal stability. Herein, we trace the crystallographic changes of Ni-based layered energy storage materials during an increase in external temperature for three different states-of-charges. The most remarkable aspect is that the onset temperature of the formation of disordered spinel structure is dominantly influenced by the intermediate tetrahedron size, the space through which the cations pass. However, the completion temperature is determined by the Li contents of the Li layer. Moreover, a highly charged state triggers the rapid reduction of Ni ions, resulting in a sudden lattice expansion during the thermally induced decomposition reaction, aggravating the danger of thermal runaway. These findings give a detailed comprehension of the crystallographic behaviors of Ni-based layered materials during the thermal decomposition reaction and contribute to designing rechargeable batteries with better thermal stability.

Evaluation on the Bond Capacity of the Fire-Protected FRP Bonded to Concrete Under High Temperature

To figure out the change in the reinforcing effect of FRP system used for the retrofit of RC beam when it is exposed to high temperature, it is required to evaluate not only the behavior of the entire beam, but also the bond performance at anchorage zone through a bond test according to the increase of external temperature. Moreover, the study to find various fire-protection methods is necessary to prevent the epoxy from reaching the critical temperature during an exposure to high temperature. In this manner, the fire-resistance performances of externally bonded (EB) FRP and near-surface-mounted (NSM) FRP to concrete block were evaluated by high-temperature exposure tests after performing a fire-protection on the surface in this paper. Board-type insulation with mortar was considered for the fire-protection of FRP system. After the fire-protection of the FRPs bonded to concrete blocks, an increasing exposure temperature was applied to the specimens with keeping a constant shear bond stress between concrete and the FRP. Based on the result, the temperature when the bond strength of the FRP disappears was evaluated. In addition, a finite element analysis was performed to find a proper method for predicting the temperature variation of the epoxy which is fire-protected with board-type insulation during the increase of external temperature. As a result of the test, despite the same fire-protection, NSM specimens were able to resist 1.54–2.08 times higher temperature than EB specimens. In the design of fire-protection of FRP system with the board-type insulation, it is necessary to consider the transfer from sides as well as the face with FRP. If there is no insulation of FP boards on the sides, the epoxy easily reaches its critical temperature by the heat penetrated to the sides, and increasing the thickness of the FP board alone for the face with FRP does not increase the fire-resistance capacity. As a result of the FE analysis, the temperature variation at epoxy can be predicted using the analytical approach with the proper thermal properties of FP mortar and board.

The Dynamic and Vibration Response of Composite Cylindrical Shell Under Thermal Shock and Mild Heat Field

In this article, the vibration and dynamic response of an orthotropic composite cylindrical shell under thermal shock loading and thermal field have been investigated. The problem is that the shell is initially located at a first temperature, and some tension caused by a mild heat field is created, then the surface temperature of the cylinder suddenly increases. The partial derivative equations of motion are in the form of couplings with the heat equations. First, the equations of motion are derived by the Hamilton principle, here first-order shear theory and considering strain-shift relations of Sanders are used. Then, the equation system including the equations of motion and energy equations by the Runge–Kutta fourth-order methodare solved. In this study, the effects of length, temperature, thickness and radius parameters on natural frequencies and intermediate layer displacement are investigated. The results show that the increase in external temperature decreases the natural frequency and increases the displacement of the system. Also, the results of radial transitions were evaluated with previous studies and it was found that it is in good agreement with the results of previous papers.

The influence of climate change on renewable energy systems designed to achieve zero energy buildings in the present: A case study in the Brazilian Savannah

The increase in external temperature results in higher energy consumption to maintain internal thermal quality, with Zero Energy Building (ZEB) being an alternative and a mandatory trend in some countries. The aim of this study is to demonstrate how climate change will affect the ZEBs, considering as a parameter the Fourth Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC). The object of study is a house located at latitude 15 °S in the centre of South America. It was used computational simulation to create future climate scenarios of 2020 (2011 to 2040), 2050 (2041 to 2070) and 2080 (2071 to 2100). Energy consumption was predicted in the current scenario with and without photovoltaic energy generation, establishing a ZEB base case. Results showed that there will be an increase in energy demand over the years, and showed that the photovoltaic system will become out of date, that is, it will not able to meet this new demand, from around 14.1% by the 2020s, 26.3% for the 2050s and 40.2% for the 2080 period. It provides subsidies for reflection on buildings energy consumption trends and de-characterization of the ZEB concept in a short period.

Estimation of Pore Size Distribution of Amorphous Silica-Based Membrane by the Activation Energies of Gas Permeation

Cobalt oxide silica membranes were prepared and tested to separate small molecular gases, such as He (dk = 2.6 Å) and H2 (dk = 2.89 Å), from other gases with larger kinetic diameters, such as CO2 (dk = 3.47 Å) and Ar (dk = 3.41 Å). In view of the amorphous nature of silica membranes, pore sizes are generally distributed in the ultra-microporous range. However, it is difficult to determine the pore size of silica derived membranes by conventional characterization methods, such as N2 physisorption-desorption or high-resolution electron microscopy. Therefore, this work endeavors to determine the pore size of the membranes based on transport phenomena and computer modelling. This was carried out by using the oscillator model and correlating with experimental results, such as gas permeance (i.e., normalized pressure flux), apparent activation energy for gas permeation. Based on the oscillator model, He and H2 can diffuse through constrictions narrower than their gas kinetic diameters at high temperatures, and this was possibly due to the high kinetic energy promoted by the increase in external temperature. It was interesting to observe changes in transport phenomena for the cobalt oxide doped membranes exposed to H2 at high temperatures up to 500 °C. This was attributed to the reduction of cobalt oxide, and this redox effect gave different apparent activation energy. The reduced membrane showed lower apparent activation energy and higher gas permeance than the oxidized membrane, due to the enlargement of pores. These results together with effective medium theory (EMT) suggest that the pore size distribution is changed and the peak of the distribution is slightly shifted to a larger value. Hence, this work showed for the first time that the oscillator model with EMT is a potential tool to determine the pore size of silica derived membranes from experimental gas permeation data.

High-sensitivity temperature sensor based on single-mode fiber for temperature-measurement application in the ocean

A high-sensitivity and low-cost optical fiber sensor for seawater temperature sensing is designed and fabricated. The large core-offset splicing sensing structure was made of single-mode fiber only. To fabricate the sensing structure precisely with a length deviation <10 μm, the relative fabrication equipment was designed and assembled. Temperature measurement experiment of the sensor was performed in a seawater bath. Also, the experimental results show that redshift of the wavelength occurs with the increase of external temperature. Its temperature response curve conforms to the quadratic curve. The temperature sensitivity can reach up to 2.293 nm/°C, and the fitting degree is up to 0.9998. Moreover, the excellent repeatability of our sensor has been verified. The sensor has great potential to measure the temperature in the ocean.

Thulium Laser in the Upper Urinary Tract: Does the Heat Generation in the Irrigation Fluid Pose a Risk? Evidence from an In Vivo Experimental Study.

The current experimental study aimed at evaluating the temperature raise of the irrigation fluid caused by the use of the thulium (Tm:YAG) and holmium laser (Ho:YAG) in the upper urinary tract (UT) of pigs. An experimental setting was designed for the investigation of differences in the temperature of the irrigation fluid in the renal pelvis of a porcine model under different flow rates and laser power settings. The experimental configuration included a single-use flexible ureteroscope, a Tm:YAG and a Ho:YAG laser system. A thermocouple was inserted through a 6F ureteral catheter that was placed parallel to the FlexVue in the renal pelvis. An additional thermocouple was placed next to the renal pelvis after open preparation of the kidney. Irrigation was achieved with either the irrigation bags placed 1 m above the level of the pig or with the use of an irrigation pump (30 and 60 compressions per minute). Tm:YAG (10, 20, 30, 40 W): The higher flow provided by the pump system minimized the increase of temperature within the renal pelvis regardless of the laser power. The external temperature increase was lower in comparison to the increase inside the renal pelvis. The internal temperature could increase up to 10.5°C from a baseline value of 23°C. Ho:YAG (10, 20 W): There was no temperature change or an increase of only 2.1°C under the different power and irrigation flow rate settings. There were no differences in the temperature between the inside and outside of the renal pelvis. The use of Tm:YAG in continuous mode with power settings up to 40 W and flow rates similar to those used in the clinical practice seemed to result in temperature increases in the irrigation fluid, which do not represent a risk for the renal tissue during the UT endoscopic surgery.

Temperature-induced variation in gene expression burst size in metazoan cells.

BackgroundGene expression is an inherently stochastic process, owing to its dynamic molecular nature. Protein amount distributions, which can be acquired by cytometry using a reporter gene, can inform about the mechanisms of the underlying microscopic molecular system.ResultsBy using different clones of chicken erythroid progenitor cells harboring different integration sites of a CMV-driven mCherry protein, we investigated the dynamical behavior of such distributions. We show that, on short term, clone distributions can be quickly regenerated from small population samples with a high accuracy. On longer term, on the contrary, we show variations manifested by correlated fluctuation in the Mean Fluorescence Intensity. In search for a possible cause of this correlation, we demonstrate that in response to small temperature variations cells are able to adjust their gene expression rate: a modest (2 °C) increase in external temperature induces a significant down regulation of mean expression values, with a reverse effect observed when the temperature is decreased. Using a two-state model of gene expression we further demonstrate that temperature acts by modifying the size of transcription bursts, while the burst frequency of the investigated promoter is less systematically affected.ConclusionsFor the first time, we report that transcription burst size is a key parameter for gene expression that metazoan cells from homeotherm animals can modify in response to an external thermal stimulus.Electronic supplementary materialThe online version of this article (doi:10.1186/s12867-015-0048-2) contains supplementary material, which is available to authorized users.

Effect of processing parameters on structural, morphological and optical Y2O3:Yb3+/Ho3+ powders characteristics

Rod-like and flake-like up-converting Y2O3:Yb3+/Ho3+ particles which are composed of nanoparticles with size less than 100nm, are prepared by a simple hydrothermal processing at 473K (3h) followed by additional thermal treatment at 1373K (3 and 12h). The effect of precursor pH value on the formation of Y2O3:Yb3+/Ho3+ is followed through X-ray powder diffractometry (XRPD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Structural refinement confirms formation of the cubic bixbyte structure (S.G. Ia-3) with the non-uniform accommodation of dopants at C2 and S6 cationic sites. Under 978nm laser excitation, strong green (530–570nm) up-conversion is observed in all samples. The emission shows a decrease in intensity with an increase in external temperature, indicating FIR (fluorescence intensity ratio) based temperature sensing behavior of 0.52% for the 5F4→5I8/5S2→5I8 transitions.

Infrared to visible upconversion in Ho3+/Yb3+ co-doped Y2O3 phosphor: Effect of laser input power and external temperature

In the present paper, Ho3+ doped and Ho3+/Yb3+ co-doped Y2O3 phosphors have been synthesized using solution combustion technique and characterized for its structure and upconversion (UC) fluorescence as a function of Yb3+ concentration. Effect of a variation in laser input power and external temperature on the UC emission intensity has been studied to explore the UC mechanism and temperature dependent behavior of the phosphor, respectively. On excitation with near infrared (NIR) light (976nm), the phosphor emits strong green emission along with relatively weak emission bands in red and blue regions at 553, 670 and 497nm due to 5S2→5I8, 5F5→5I8 and 5F3→5I8, respectively. The emission shows a decrease in intensity with an increase in external temperature, however contrary to the normal behavior of Ho3+, no significant change in the FIR (fluorescence intensity ratio) of 5F4→5I8 and 5S2→5I8 transitions is noted in the present host. This peculiar behavior of the sample with external temperature has been explained by temperature dependent lifetime study of the thermally coupled levels.

Thermo-sensitive and photoluminescent hydrogels: Synthesis, characterization, and their drug-release property

Multifunctional hydrogels that simultaneously possess semi-interpenetrating networks structure, strong photoluminescence, and temperature sensitivity were successfully fabricated based on the crosslink of poly(acrylamide) (PAAm) in the presence of poly(N-isopropylacrylamide) (PNIPAM) and CdTe quantum dots (QDs) at a mild condition. With the increase of external temperature, the photoluminescence (PL) intensity and emission peak of the hydrogels gradually decreased and red-shifted, respectively. Decreasing the temperature, the PL intensity and emission peak of the hydrogels could back to their initial values again. Moreover, drug-release experiments on the multifunctional hydrogels demonstrated that the release rate can be tuned by the environmental temperature and the content of PNIPAM. In addition, biocompatible hyperbranched polyglycerol functionalized QDs (QD@HPGs) instead of pristine QDs can also be incorporated into the hydrogels, affording biocompatible hydrogels which could still exhibit temperature-sensitive photoluminescence and drug-release behaviors.

Thermoreflectance imaging of laser diodes and VCSELs along and perpendicular to the emission direction

Thermal characterization of semiconductor lasers is an important issue for optoelectronics. This paper presents our thermoreflectance measurements on two different types of laser diodes: classical ridge laser diodes and vertical cavity surface emitting lasers (VCSELs). We first studied the external temperature increase in ridge diodes in order to determine inhomogeneity. Then, we tried to determine the inner temperature of the VCSELs.

Fast responsive poly( N-isopropylacrylamide) hydrogels prepared in phenol aqueous solutions

Fast responsive poly( N-isopropylacrylamide) (PNIPAAm) hydrogels with improved properties were prepared in phenol aqueous solutions with different concentrations. Due to the expanded network structure in water, the resulted hydrogels are capable of absorbing a large amount of water, i.e. exhibits a much increased swelling ratio at room temperature. Importantly, the hydrogels demonstrated much faster response rate than that of traditional PNIPAAm hydrogel upon external temperature increase.

Mammalian freeze-dried sperm can maintain their calcium oscillation-inducing ability when microinjected into mouse eggs

Mammalian freeze-dried sperm can maintain their genetic integrity and event support full development to term when microinjected into mature oocytes. However, it is unknown whether freeze-dried sperm can still maintain their calcium oscillation-inducing capability. Here, we microinjected mouse and bovine freeze-dried sperm into mouse MII oocytes and examined their calcium oscillation-inducing ability following intracytoplasmic sperm injection (ICSI). Two pieces of information are revealed. First, nearly all oocytes injected with a freeze-dried mouse sperm head or a bovine sperm showed fertilization-like calcium oscillations, indicating that freeze-drying treatment does not affect the activity of the sperm factor responsible for calcium oscillations. Second, freeze-dried sperm exhibited high resistance to external temperature increase. This is shown by the finding that the freeze-dried sperm can maintain their calcium oscillation-inducing capacity even following exposure to 100 °C for 3 h. We therefore conclude that mammalian sperm can maintain their calcium oscillation-inducing capability following freeze-drying, rehydration, and ICSI treatments.

Thermal risks from LED- and high-intensity QTH-curing units during polymerization of dental resins.

The aim of this study was to test the ability of an infrared (IR) camera to assess temperature changes and distributions in teeth below restorations when quartz-tungsten-halogen (QTH) and light-emitting diode (LED) curing lights were used to photopolymerize the restorative material. Our hypothesis was that the higher power density and broader spectral distribution of the QTH source would cause greater increases in tooth temperature than the LED source, and that these differences would be best demonstrated with the IR camera. Cavities were prepared on human third molars and restored with a resin composite restorative material. The material was light-cured using three light-curing sources using several exposure times. The external (outside the tooth) and internal (inside the pulp chamber) temperature changes during polymerization of the composite material were recorded over 360 s with thermocouples and an IR camera. Using thermocouples the maximum increase in external temperature (+17.7 degrees C) was reported for the Swiss Master light after 20 s of curing time while the minimum temperature rise (+7.8 degrees C) was reported for the Freelight 2. Whereas a 2.6 degrees C increase in internal temperature was observed after curing 20 s with the Freelight 2, 7.1 degrees C was reported after 60 s of light exposure to Astralis 10. Infrared images showed similar trends in external-internal rises in temperature as the thermocouples, although temperatures measured by the IR were generally higher. These results indicate that the higher power density QTH sources caused greater increases in tooth temperatures than the LED source and that thermocouples may underestimate the heat applied to the tooth.

Spatial and Temporal Profiling of Protrusion in Magnetic Recording Heads

An increase in external temperature or internal heating by writing can induce protrusion or strain of thin film layers in a magnetic recording head. To profile the protrusion, the surface topography and the temperature distribution are imaged in fixed heads by scanning probe and optical microscopy. Near the poles and the shields, the protrusion is at a peak, producing a risk of head-disk interaction. The dynamics are elucidated in flying heads over a disk by measuring the amplitude of a reference pattern with the read head. The temporal profiling technique can be applied both in component testing on spinstands and reliability testing in fully integrated disk drives. For either heating or cooling of the heads, the characteristic time constant for protrusion is 100 /spl mu/s and reaches 95% of the plateau after 1 ms. The protrusion is linear with temperature and is reversible, implying that the strains are within the elastic limit. Furthermore, variation of the write pulse shape suggests that Joule heating is more significant than eddy current or hysteresis losses in inducing protrusion.