Interaction Of High Temperature Research Articles

Cause Analysis of Condensed Water Induced Bulging in High-Pressure Steam Tee Joints of a Pyrolyzer

High-pressure steam pipes inevitably suffered from the reciprocal interaction of high pressure and temperature during a long-period service, causing deformation and cracking. However, only limited studies about abnormal bulging caused by condensed water have been carried out. To study the relationship between bulging and condensed water, bulging tee joints belonging to high-pressure steam pipes were investigated with a macro visual inspection, chemical composition analysis, and metallographic microscopy. According to the analysis of the bulging samples, pearlite spheroidization was found in the abnormal bulging tee joint. The ANSYS FLUENT modeling indicated that the tube wall of bulging tees was continuously subjected to alternating stress, causing the cyclic transformation of the liquid–gas phase inside the tee joint. The results indicate that the stress produced by a condensed water droplet ranges from 532.8 MPa to 59 MPa, continuously exerting pressure on the tube wall of the tee joint. When combined with the variation in the temperature field, the temperature of the severe bulging tee joint and slight bulging tee joint alternates. Further modeling illustrates that the stress generated by the impact of condensed water droplets on the high-temperature tee joints causes a ratcheting effect, which is identified as the main factor contributing to the bulging of the tee joint. Deterioration of the microstructure is considered a secondary mechanism.

Interaction of high temperature and NO2 exposure on asthma risk: In vivo experimental evidence of inflammation and oxidative stress

Allergic asthma is a complicated respiratory disease with many concerns. Mounting epidemiological evidence linked temperature (T) and NO2 with allergic asthma, yet toxicological studies remain scarce. We conducted an in vivo study to explore toxicological evidence in T-NO2 interaction on allergic asthma, to investigate underlying toxicological mechanisms. 90 male Balb/c mice were randomly and equally divided into 6 groups including saline control, ovalbumin (OVA)-sensitized, OVA + 35 °C, OVA + NO2, OVA + 35 °C + NO2, and OVA + 35 °C + NO2 + capsazepine (CZP), adopting treatment for 38 days. We measured pulmonary functions of inspiratory resistance (Ri), expiratory resistance (Re) and airway compliance (Cldyn), serum protein biomarkers, indexes of pulmonary inflammation, histopathological changes and protective effects of CZP. Airway hyperresponsiveness (AHR) was aggravated by high T (35 °C) and NO2 (5 ppm) co-exposure with a series of aggravating asthmatic symptoms including airway wall thickening, lumen stenosis, goblet cell proliferation, mucus hypersecretion, and subepithelial fibrotic hyperplasia, providing evidence in the toxicological impact of high T-NO2 interaction. The biomarkers of serum immune functions (Total-IgE, OVA-sIgE and IL-4), pro-inflammation (IL-6 and TNF-α), oxidative stress cytokines (8-OHdG, ROS and MDA), airway resistance (Ri and Re), and TRPV1 expression significantly increased, while IFN-γ, GSH and airway compliance (Cldyn) significantly decreased with co-exposure to high T and NO2. We observed that CZP addition significantly ameliorated these toxicological effects and biomarker levels induced by heat-NO2 interaction. Our results suggest a toxicity of heat-NO2 interaction on asthma with clear mechanisms, which can be ameliorated by CZP, indicating that both oxidative stress and TRPV1 expression may be primarily responsible for asthma of heat-NO2-induced toxicity.

Experimental investigation on the evolution of damage and seepage characteristics for red sandstone under thermal–mechanical coupling conditions

Rock masses in underground space usually experience the coupling of high-temperature field, stress field and seepage field, which gives them complex mechanical behavior and permeability characteristics. To study the mechanical properties and permeability characteristics of red sandstone under different temperature environments, a seepage test under high temperature and triaxial compression is carried out based on the RLW-2000 multi-field coupling tester. The results show that the plastic flow of red sandstone at the stress peak under the same temperature is more obvious with the increase of confining pressure. In addition, as the confining pressure gradient increases, the permeability decreases and the trend becomes slower. And the higher the operating temperature, the easier to produce seepage channels inside the rock sample. The development of fissures is rapidly developed under the effect of temperature, so the seepage channels are widened and increased, and the permeability is greatly increased. The constitutive model of rock statistical damage considering the interaction of high temperature and osmotic pressure was constructed based on the experimental data and combining theoretical methods to reveal the characteristics of permeability evolution induced by thermal damage of rocks. The research results can be used as a reference for monitoring rock stability during geological engineering projects involving thermal–seepage–stress coupling conditions.

Effects of Combined High Temperature and Waterlogging Stress at Booting Stage on Root Anatomy of Rice (Oryza sativa L.)

In recent years, the alternating occurrence of high temperature and waterlogging disasters in South China has seriously reduced the yield of single cropping rice. Studying the changes in anatomical structure of the rice root system could provide theoretical basis for understanding the mechanisms of high temperature and waterlogging stress. To examine interactions between temperature and waterlogging stress, an experiment was set up in a growth chamber consisting of two temperatures (moderate, 30–34 °C and high, 35–38 °C) with three depths of flooding (0–5, 10 and 15 cm). Treatments commenced at the booting stage and lasted five days, after which all treatments were returned to a 0–5 cm flooding depth and the same temperature regime. Observations were made immediately after cessation of treatments, then after 5, 10 and 20 d to test the effect of treatments on subsequent root anatomical development. The low-stress control (0–5 cm, medium temperature) showed no change with time in aerenchyma area, thickness of the outer root, stele diameter, and the number nor diameter of xylem vessels. Root diameter and stele diameter under the high-stress control (0–5 cm, high temperature) were decreased by 29.09% and 15.28%, respectively, at the booting stage, whereas the high stress control (15 cm, high temperature) affected only the vessel diameter, reducing it by 14.11% compared with that in the low-stress control (0–5 cm, medium temperature). Compared to the high-stress control (0–5 cm, high temperature), the interaction of high temperature and waterlogging stress alleviated the inhibiting effect of the changes in the root system, especially after the end of the stress. We thought that waterlogging could reduce the damage of high temperature on rice root growth. Low water depth waterlogging has little effect on rice root system and aerenchyma area root diameter at 0, 5, 10 and 20 d after the stress ended, and the thickness of the outer root, stele diameter and the number and diameter of vessels at 0 d under M15 (15 cm, medium temperature) had no significant difference compared with M5 (0–5 cm, medium temperature). However, the increase in rice root diameter, stele diameter, thickness of the outer root cortex depth and vessel diameter were inhibited under high temperature stress at the booting stage. Root diameter and stele diameter under H5 (0–5 cm, high temperature) were decreased by 29.09% and 15.28%, respectively, at the booting stage, whereas H15 (15 cm, high temperature) affected only the vessel diameter, reducing it by 14.11% compared with that in the M5. Compared to H5, the interaction of high temperature and waterlogging stress alleviated the inhibiting effect of the changes in the root system, especially after the end of the stress. We thought that waterlogging could lighten the damage of high temperature on rice root growth.

Interaction of high seawater temperature and light intensity on photosynthetic electron transport of eelgrass (Zostera marina L.)

The interaction of widely recognized causes of eelgrass decline (high seawater temperature and limited light intensity) on photosynthetic electron transport was investigated via chlorophyll fluorescence technique. High seawater temperature combined light intensity significantly increasing the relative maximum electron transport rate (rETRmax); at critical temperature of 30 °C, the rETRmax increased with the enhancement of light intensity, indicating the elevation of overall photosynthetic performance. Based on the magnitude of effect size (η2), light intensity was the predominant factor affecting the performance index (PIABS), indicating that photosystem II (PSII) was sensitive to light intensity. Moreover, the donor side was severely damaged as evidenced by the higher decrease amplitude of fast component and its subsequent incomplete recovery. The reaction center exhibited limited flexibility due to the slight decrease amplitude in maximum photochemical quantum yield. In contrast with PSII, photosystem I (PSI) was more sensitive to high seawater temperature, based on the magnitude of η2 derived from the maximal decrease in slope. High seawater temperature significantly increased PSI activity, plastoquinol reoxidation capacity, and probability for electron transfer to final PSI electron acceptors. Moreover, it combined elevated light intensity significantly stimulated the activity of cyclic electron flow (CEF) around PSI. Higher activity of both PSI and CEF contributed to balancing the linear electron transport via alleviating the over-reduction of the plastoquinone pool, exhibiting flexible regulation of photosynthetic electron transport at critical temperature. Therefore, limited light intensity decreased the tolerance of eelgrass to critical temperature, which might be a factor contributing factor in the observed decline.

Investigation on performance characteristics and metallographic transformation on drilling aluminium/titanium sandwich

Materials sandwiches of aluminium/titanium are widely used in structural aerospace, especially in the surface coating and skeletons of aircrafts. Due to their inhomogeneous behavior and poor machinability, drilling aluminium/titanium sandwich in one-shot operation has brought great challenges to the modern manufacturing community. In this paper, a series of experiments were conducted to understand and characterize the process of drilling aluminium/titanium sandwich. Experimental results have shown that the serrated chip is not common in drilling. Only the outer edge of the spiral chip has saw teeth because of the variable cutting speed along the cutting edge. In addition, a better understanding of the phase transformation on surface and subsurface of drilled hole has been provided. Two kinds of phase transformations on the surface of drilled hole have been observed: one is the allotropic transformation from α to β phase and the other is that from β to minor phases α′ (hexagonal martensites). All these are mainly due to the interaction of mechanical force and high temperature.

Effect of Steam Flash Explosion Pretreatment on Phytate Degradation of Wheat Bran

Whole wheat flour contains many nutrients which is mainly located in wheat bran, but it has a poor bioavailability because of the massive presence of antinutritional factor phytate. To improve the bioavailability, steam flash explosion (SFE) was first employed to phytate degradation in wheat bran. Five levels of steam pressure (0.5, 1.0, 1.5, 2.0, and 2.5 MPa) and six levels of residence time (30, 60, 90, 120, 150, and 180 s) were used to investigate the phytate and color changes of wheat bran treated by SFE. The optimum process was determined at steam pressure of 2.5 MPa and residence time of 60 s. Under this process, the satisfactory phytate degradation (around 87 %) could be obtained, whereas the degree of color deepening of treated wheat bran is proportional to the phytate degradation. Observation of scanning electron microscopy (SEM) revealed that the structure of wheat bran was completely destroyed by SFE. This destruction causes the phytate to be exposed to high temperature and high pressure and consequently degraded. High-performance liquid chromatography (HPLC) results indicated that SFE could effectively change phytate into low inositol phosphate salts. As shown in the Fourier transform infrared (FT-IR) spectroscopy analysis, this change was attributed to the decomposition of phytate by interrupting the P–O–C group. Overall, phytate degradation in wheat bran during SFE attributed to the interaction of high pressure, high temperature, and acid hydrolysis.

Effect of Interaction of Waterlogging and High Temperature after Anthesis on Photosynthetic Characteristics of Flag Leaf and Yield in Winter Wheat

Waterlogging and high temperature are main stress factors during late growing period of winter wheat(Triticum aestivum L.) in Yangtze Valley region of China.To understand the effect of interaction of waterlogging and high temperature on photosynthetic characteristics and grain yield of wheat,we carried out a pot experiment,using the variety of Yannong 19,in continuous growing seasons from 2009 to 2011.At grain-forming(5-8 d after anthesis) and milking(15-18 d after anthesis) stages,waterlogging(1 cm of surface water layer),high temperature(35±2℃ of daytime/25±2℃ of nighttime),and waterlogging + high temperature stresses were imposed to wheat plants,separately.Waterlogging,high temperature,and both stresses showed significantly effects on photosynthetic characteristics of flag leaf and yield reducing photosynthetic rate(Pn),chlorophyll content(SPAD reading),stomatal conductance(Gs),and transpiration rate(Tr);enhancing intercellular CO2 concentration(Ci);and declining grain number per spike,1000-grain weight,and grain yield.However,in the case,spike number per pot was not affected significantly.Thus,the effects of waterlogging and high temperature on Pn did not result from stomata factor of flag leaf.The average relative injury rates(RIR) of yield were 37.7% for waterlogging + high temperature treatment,21.1% for waterlogging treatment,and 17.6% for high temperature treatment.Stress showed higher RIR at grain forming stage(30.8%) than at milking stage(20.1%).There was significant interaction between waterlogging and high temperature,and grain-forming stage was more sensitive to the interaction than milking stage.

The effects of the relative humidity on the insecticidal expression level of Bt cotton during bolling period under high temperature

Bt transgenic cotton has shown unstable insect-resistance during boll period in cotton industry. The objective of this study was to investigate the effect of the relative humidity on the leaf Bt protein content of two different types of Bt cotton cultivars under high temperature condition. During the 2009 and 2010 cotton growth seasons, the leaves insecticidal protein concentrations of the two Bt cultivars were measured under high (water-sprayed every day) and low field relative humidity (no water spray) during the high temperature period in three field experimental sites. In 2010, the environmentally controlled experiment with 3 humidity (50%, 70% and 90%) treatments under 37°C was conducted to further investigate the effects of the relative humidity on the Bt efficacy and mechanism of nitrogen metabolism at Yangzhou University Farm. The results of the study showed that the reduction of cotton field RH under high temperature further decreased the leaf Bt insecticidal protein levels. The high RH treatment at boll developing period caused relatively less and slower decline of the insecticidal protein. In contrast, the low RH treatment had greater and faster drop of the Bt efficacy. The green house experiment further indicated that the greater reduction of the leaf entoxin was detected under extreme humidity(RH 90% and RH 50%) under high temperature compared to RH 70%. Correspondingly, the higher leaf amino acid contents, lower soluble protein levels and the greater protease activities under the extreme humidity than the RH 70% treatment were observed during the whole treatment period. It indicated that the reduced insect-resistance of Bt cotton that is closely correlated to extreme weather during boll developing period caused by the interaction of high temperature and extreme relative humidity. Leaf soluble protein reduction caused by extreme relative humidity under high temperature may contribute to a further decrease of the Bt toxin in the boll period of Bt cotton.

Study on Alloyed Surface Layer of Wear Resistant Castings by Evaporable Pattern Castings Infiltration Process

Wear-resistant casting was made by V-EPC infiltration process. This paper puts forward and analyses the mechanical properties and forming mechanism of the layer. The matrix material was high boron steel casting. By partial casting alloyed, the surface composite materials layer was ceramic particles, such as WC, Ferrochromium, and Borax, etc. High boron molten metal was infiltrated into the composite layer and a good cast-infiltration layer may be formed by the interaction of vacuum and high temperature. The test result shows that using this process we can get the casting surface which is special abrasion-resistance with the remarkable characteristics such as simple process and low cost. It is a new process that wear-resistant casting will be made of.

Endosperm and pericarp size in wheat (Triticum aestivumL.) grains developed under high temperature and drought stress conditions

Drought and high temperature are two major factors limiting crop production. The two stresses occur together in many regions of the world but they usually are investigated separately. Irrespective of the genotype, growth or treatment conditions, grain growth was severely reduced when wheat plants were exposed to high temperature, drought and combination of both the stresses during endosperm cell division. The extent of thermal as well as drought induced disruption of grain development, however was dependent on genotype. This structural data support the hypothesis that high temperature and drought during endosperm cell division reduces grain sink potential and subsequently mature grain mass, mainly by disrupting cell divisions in peripheral and central endosperm and thus reducing endosperm length and breadth to a considerable extent. The interaction of high temperature and drought stresses resulted in stronger reduction of pericarp thickness and endosperm size than either stress alone.

Effects of the Microstructure and Mechanical Properties for Wear Resistant Casting Surface with Vacuum Evaporable Pattern Casting Infiltration Process

Wear-resistant casting was made by V-EPC infiltration process. The matrix material was high boron steel casting. Surface composite materials layer was ceramic particles, such as WC, Ferrochromium, and Borax, etc. High boron molten metal was infiltrated into the composite layer and a good cast-infiltration layer may be formed by the interaction of vacuum and high temperature. The wear-resistant casting made with this process has high strength, hardness, and good wear-resistance. It is a new process that wear-resistant casting will be made of.

Tensile behavior and microstructural evolution of a carbon/silicon carbide composite in simulated re-entry environments

Carbon fiber reinforced silicon carbide matrix composites with a protective coating were prepared by chemical vapor infiltration. Their tensile strength was about 240–250 MPa at room temperature, and 330–390 MPa in vacuum. Tensile behavior in a simulated re-entry environment was studied and compared with that in vacuum. The microstructural evolution on tensile fracture surfaces were investigated by scanning electron microscopy, and an oxidation damage pattern of fibers on tensile fracture surface was presented and discussed. A significant strength reduction was observed in re-entry environments due to the interaction of load, high temperature, and oxidation. The non-uniform oxidation of fibers weakened the load-carrying ability due to decreasing effective loaded area and hence strength. Finally, a minimum diameter of total fiber cluster embedded in composites is suggested about 220 μm for use under high load in re-entry environments at 1800 °C.

Responses of massive and branching coral species to the combined effects of water temperature and nitrate enrichment

The branching coral species Pocillopora damicornis (Linnaeus) and the massive coral species Porites lobata Dana were exposed for 30 days to different temperatures and nitrate concentrations to study the response of the coral–zooxanthella symbiosis. Results suggest that the effect of nitrate enrichment on the polyp–zooxanthella symbiosis varies according to the coral morphology. After the experimental period only 30% of P. damicornis colonies remained healthy, in contrast to 90% of P. lobata. The branching P. damicornis was significantly affected by the addition of nitrate, whereas P. lobata was significantly influenced by water temperature. The two species showed enhanced zooxanthella volume, and chlorophyll contents per cell under high nitrate concentrations. The reduced zooxanthellae density in both species indicated a detrimental influence of the interaction of high nitrate and high temperature. Tissue soluble proteins in P. lobata were significantly reduced by elevated temperature. Results showed that tissue soluble proteins and chlorophylls in P. lobata were from two- to three-fold higher than in P. damicornis. The number of zooxanthellae in P. lobata was double that of P. damicornis. Therefore, we suggest that the slow-growing species P. lobata is better able to cope with changing environmental conditions than the fast-growing coral P. damicornis.

Interaction of drought and high temperature on photosynthesis and grain-filling of wheat

Drought and high temperature often occur simultaneously, but their effects on crops are usually investigated individually. Our objective was to compare effects of drought, high temperature, and their interactions on photosynthesis and grain-growth of wheat (Triticum aestivum L.). Plants (cv. Len) were grown uniformly in well-watered soil at 25/20 ± 2 °C day/night until anthesis, when they were subjected to regimes of no drought (soil at field capacity) and drought (plant water potential of −.0 to −2.4 MPa) at 15/10, 25/20, and 35/30 °C in controlled environments until physiological maturity. Drought decreased photosynthesis, stomatal conductance, viable leaf area, shoot and grain mass, and weight and soluble sugar content of kernels but increased plant water-use efficiency. High temperature hastened the decline in photosynthesis and leaf area, decreased shoot and grain mass as well as weight and sugar content of kernels, and reduced water-use efficiency. Interactions between the two stresses were pronounced, and consequences of drought on all physiological parameters were more severe at high temperature than low temperature. The synergistic interactions indicated that productivity of wheat is reduced considerably more by the combined stresses than by either stress alone, and that much of the effect is on photosynthetic processes.

The interaction of high temperature and elevated CO2 on photosynthetic acclimation of single leaves of rice in situ

Rice (Oryza sativa L. cv. IR72) was grown at three different CO2 concentrations (ambient, ambient + 200 μmol mol−1, ambient + 300 μmol mol−1) at two different growth temperatures (ambient, ambient + 4°C) from sowing to maturity to determine longterm photosynthetic acclimation to elevated CO2 with and without increasing temperature. Single leaves of rice showed a cooperative enhancement of photosynthetic rate with elevated CO2 and temperature during tillering, relative to the elevated CO2 condition alone. However, after flowering, the degree of photosynthetic stimulation by elevated CO2 was reduced for the ambient + 4°C treatment. This increasing insensitivity to CO2 appeared to be accompanied by a reduction in ribulose‐1.5‐bisphosphate carboxylase/oxygenase (Rubisco) activity and/or concentration as evidenced by the reduction in the assimilation (A) to internal CO2 (C1) response curve. The reproductive response (e.g. percent filled grains, panicle weight) was reduced at the higher growth temperature and presumably reflects a greater increase in floral sterility. Results indicate that while CO2 and temperature could act synergistically at the biochemical level, the direct effect of temperature on floral development with a subsequent reduction in carbon utilization may change sink strength so as to limit photosynthetic stimulation by elevated CO2 concentration.

The interaction of high temperature and elevated CO2on photosynthetic acclimation of single leaves of rice in situ

The interaction of high temperature and elevated CO2on photosynthetic acclimation of single leaves of rice in situ

Thermal flooding injury of woody swamp seedlings

1. 1.| Taxodium distichum (L.) Richard (bald cypress) and Nyssa aquatica L. (water tupelo) seedlings were exposed to varying combinations of elevated temperature and flooding conditions. 2. 2.|High temperature flooded soil conditions reduced growth of both species and reduced photosynthesis and transpiration of water tupelo. 3. 3.|Root respiration, ethylene production and carbohydrate concentrations were affected by high temperature flooded conditions. 4. 4.|A hypothesized mechanism of the interaction of high temperature and flooding is discussed.

Interaction of High Temperature and Salmonella pullorum Antigen Concentration on Serum Agglutinin and Corticosteroid Responses in White Rock Chickens

In three experiments, 6- to 7-week-old chickens were exposed to one or two standard heating episodes and were injected immediately afterward with different concentrations of heat-killed Salmonella pullorum antigen (Ag) or phosphate-buffered saline. The standard heat episode consisted of three .5-hr exposures of 44 to 46 C with .5-hr periods of 22 C between exposures. Nonheated chickens were maintained at 22 C. When two heating episodes were used, there was a 12-hr interval between episodes. Sera from blood collected at 0 through 15 days postimmunization (PI) were titrated for total agglutinins and assayed for corticosteroids in all three experiments. Additionally, in Experiment 3, sera were titrated for 2-mercaptoethanol-resistant (2-MER) antibody.Total agglutinins were suppressed from 5 through 13 days PI by one heating episode in birds receiving lower doses of Ag but not in those receiving higher doses. When birds were exposed to two heat episodes, 12 hr apart, total agglutinin titers were suppressed in birds receiving the low Ag dose during the induction phase (4 to 5 days PI) only. During the declining phase (7 to 14 days PI), the effect was reversed, and titers were significantly lower in heated birds receiving the higher dosage. These results are similar to those previously obtained with ACTH (adrenocorticotropin).Determination of 2-MER antibody indicated that IgM was probably suppressed during the induction of the immune response but that IgG was suppressed during the declining phase of the response.Serum corticosteroid concentrations were significantly increased immediately after exposure to high temperature. There were also small, but significant, increases in serum corticosteroids 8 to 11 days after immunization in birds that received high Ag doses and were exposed to high temperature.

Interaction of CPTA and High Temperature on Carotenoid Synthesis in Tomato Fruit

Summary The effect of 2-(4-chlorophenylthio) ethyl-diethylammonium chloride (CPTA) on the carotenoid composition of Rouge de Marmande and high-beta tomato fruits stored at 20° and 30°C is examined. High-temperature (30°C) inhibits lycopene formation in untreated Rouge de Marmande fruits, and they ripens to a yellow colour in contrast to the pinkish yellow colour of the CPTA-treated fruits. The formation of β-carotene is greatly inhibited in the CPTA-treated high-beta fruits, and lycopene is accumulated at the expense of β-carotene. It is suggested that in high-beta fruit CPTA may regulate the carotene synthesis in a manner similar to β+ and mβ+ alleles.