Analysis Of Thermal Response Research Articles

Investigation on eddy current pulsed thermography to detect hidden cracks on corroded metal surface

This paper explores the feasibility of eddy current pulsed thermography (ECPT) to detect hidden cracks on corroded metal surface without removing the corrosion layer. The detection mechanisms are analyzed by using electromagnetic and heat conduction theories. Experiments are conducted on a metallic bar with three hidden cracks and the validity of ECPT is verified with the analysis of IR images and thermal responses. In order to further improve the detection sensitivity of ECPT, the principal component analysis (PCA) is applied to enhance the features of hidden cracks in the raw IR images by eliminating the effects of uneven corrosion and non-uniform heating. It is found that ECPT combined with PCA provides a convenient and effective way to detect hidden cracks on corroded metal surface.

Analysis of behaviour patterns and thermal responses to a hot–arid climate in rural China

Climate can greatly affect building design, life style and thermal perception for all groups of people; however, this phenomenon has not yet been rigorously evaluated in China's hot–arid climate. The aim of this paper is to present the results of a thermal comfort survey by evaluating the influence of the hot–arid climate upon the behavioural patterns and thermal comfort responses of 160 residents in 65 traditional vernacular houses in Turfan, China, in 2011. In this survey, there were 206 sets of effective data, and the features of the traditional residential buildings and the human behaviour patterns in Turfan were described and analysed. The results showed that the diversified courtyards and shade spaces were the most obvious features of traditional houses in Turfan. People here typically spend most of their time in one of two spaces for eating, resting, and entertaining. It was found that the preferred temperature was 26.5°C. The preferred air velocity occurred at 0.62m/s. A suitable air velocity range of 0.15–1.24m/s was suggested in Turfan. Moreover, the neutral temperature of the local people was 30.1°C (tg or to). The upper limits of the 80% acceptable zone by using the direct and indirect acceptability method were 32.7 and 33.8°C, respectively. The neutral temperature and upper limit of the acceptable zone in Turfan were higher than those of the adaptive standards. Attention should be paid to the role of thermal comfort in influencing building design by using simple passive cooling strategies. The above results are believed to be potentially valuable for the design and evaluation of residential buildings located in hot–arid climate.

C<sup>0</sup>-type Reddy's theory for composite beams using FEM under thermal loads

To analyze laminated composite and sandwich beams under temperature loads, a C0-type Reddy\'s beam theory considering transverse normal strain is proposed in this paper. Although transverse normal strain is taken into account, the number of unknowns is not increased. Moreover, the first derivatives of transverse displacement have been taken out from the in-plane displacement fields, so that the C0 interpolation functions are only required for the finite element implementation. Based on the proposed model, a three-node beam element is presented for analysis of thermal responses. Numerical results show that the proposed model can accurately and efficiently analyze the thermoelastic problems of laminated composites.

High Temperature Exposure of HPC – Experimental Analysis of Residual Properties and Thermal Response

The effect of high temperature exposure on properties of a newly designed High Performance Concrete (HPC) is studied in the paper. The HPC samples are exposed to the temperatures of 200, 400, 600, 800, and 1000°C respectively. Among the basic physical properties, bulk density, matrix density and total open porosity are measured. The mechanical resistivity against disruptive temperature action is characterised by compressive strength, flexural strength and dynamic modulus of elasticity. To study the chemical and physical processes in HPC during its high-temperature exposure, Simultaneous Thermal Analysis (STA) is performed. Linear thermal expansion coefficient is determined as function of temperature using thermodilatometry (TDA). In order to describe the changes in microstructure of HPC induced by high temperature loading, MIP measurement of pore size distribution is done. Increase of the total open porosity and connected decrease of the mechanical parameters for temperatures higher than 200 °C were identified.

Influence of regional groundwater flow on ground temperature around heat extraction boreholes

The increasing popularity of ground-coupled heat pumps has resulted in almost 20% of all Swedish family houses being heated this way. To avoid undesirable interactions between neighboring boreholes and disturbance of the ground temperature, the general rule and recommendation of Swedish authorities is that the distance between two neighboring boreholes must be ≥20m. However, according to previous studies, relatively low groundwater flow rates may significantly reduce the borehole excess temperature compared to the case of pure heat conduction.In this work the Influence Length is defined and its relations with flow rate, real thermal conductivity of the ground and effective thermal conductivity obtained by thermal response analysis are investigated. The aim of this study was to find a way to use the thermal response test as a means to determine the groundwater flow influence in order to reduce the borehole spacing perpendicular to groundwater flow direction.The results confirm that very low groundwater flow rates are enough to significantly reduce the Influence Length, hence this is a crucial parameter which should be considered. Moreover, a first estimation, even before the thermal response test analysis, of the Influence Length is possible if the knowledge of hydrogeological conditions of the site allows good predictions about real thermal conductivity of the ground and flow rate.

Thermal Analysis of a Jet Deflector Subjected to Liquid Engine Jet Exhaust in a Static Test

The survivability of a jet deflector encountering severe heating conditions due to the direct impingement of exhaust gases from a liquid engine is analyzed. Using engineering methods the thermal environments and temperature history are estimated. The cooling of the jet deflector using a water stream into the exhaust stream through spray nozzles located upstream from the deflector to reduce the exhaust temperature is considered. Since the major source of heating of the jet deflector is by convection, the convective heating due to jet impingement is evaluated. A flow field from the exhaust of the liquid engine is generated using a finite-volume-based Navier–Stokes computational fluid dynamics solver. For evaluating convective heat transfer coefficient, engineering methods are used based on the flow-field data generated. The theoretical flow-field data generated do not account for jet water mixing. To account for the water jet effect, an energy balance method is used to estimate the jet temperature and a one-dimensional thermal response analysis is carried out using in-house design code. The computed temperature data are compared with the measured temperature data and the survivability of the jet deflector is assured.

The genome sequence of the Antarctic bullhead notothen reveals evolutionary adaptations to a cold environment.

BackgroundAntarctic fish have adapted to the freezing waters of the Southern Ocean. Representative adaptations to this harsh environment include a constitutive heat shock response and the evolution of an antifreeze protein in the blood. Despite their adaptations to the cold, genome-wide studies have not yet been performed on these fish due to the lack of a sequenced genome. Notothenia coriiceps, the Antarctic bullhead notothen, is an endemic teleost fish with a circumpolar distribution and makes a good model to understand the genomic adaptations to constant sub-zero temperatures.ResultsWe provide the draft genome sequence and annotation for N. coriiceps. Comparative genome-wide analysis with other fish genomes shows that mitochondrial proteins and hemoglobin evolved rapidly. Transcriptome analysis of thermal stress responses find alternative response mechanisms for evolution strategies in a cold environment. Loss of the phosphorylation-dependent sumoylation motif in heat shock factor 1 suggests that the heat shock response evolved into a simple and rapid phosphorylation-independent regulatory mechanism. Rapidly evolved hemoglobin and the induction of a heat shock response in the blood may support the efficient supply of oxygen to cold-adapted mitochondria.ConclusionsOur data and analysis suggest that evolutionary strategies in efficient aerobic cellular respiration are controlled by hemoglobin and mitochondrial proteins, which may be important for the adaptation of Antarctic fish to their environment. The use of genome data from the Antarctic endemic fish provides an invaluable resource providing evidence of evolutionary adaptation and can be applied to other studies of Antarctic fish.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-014-0468-1) contains supplementary material, which is available to authorized users.

A composite cylindrical model and its application in analysis of thermal response and performance for energy pile

Energy pile is a special vertical heat exchanger with the advantage of saving land area for buried pipe in recent years. Based on the composite line source model and cylindrical model, this paper presents a composite cylindrical model, and the heat capacity of pile in the borehole in ground source heat pump system (GSHP) was considered in the model. The model can be used in energy pile with a large diameter. It was validated by comparing to a 3-D numerical model which had been compared with a measured data set. The thermal performance of various layout forms of heat exchangers in energy pile was analyzed. In addition, the model was applied to a project of thermal response test (TRT) to estimate the thermal property parameters of soil. The simulation results showed that the composite cylindrical model have a better agreement from start of the test with measurement data. The model gives a new simulation tool in analysis of performance and TRT for energy pile.

Intrinsic SiOx-based unipolar resistive switching memory. II. Thermal effects on charge transport and characterization of multilevel programing

Multilevel programing and charge transport characteristics of intrinsic SiOx-based resistive switching memory are investigated using TaN/SiOx/n++Si (MIS) and TiW/SiOx/TiW (MIM) device structures. Current transport characteristics of high- and low-resistance states (HRS and LRS) are studied in both device structures during multilevel operation. Analysis of device thermal response demonstrates that the effective electron energy barrier is strongly dependent on the resistance of the programed state, with estimates of 0.1 eV in the LRS and 0.6 eV in the HRS. Linear data fitting and conductance analyses indicate Poole-Frenkel emission or hopping conductance in the low-voltage region, whereas Fowler-Nordheim (F-N) or trap-assisted tunneling (TAT) is indicated at moderate voltage. Characterizations using hopping transport lead to hopping distance estimates of ∼1 nm in the LRS for both device structures. Relative permittivity values (εr) were extracted using the Poole-Frenkel formulism and estimates of local filament temperature, where εr values were ∼80 in the LRS and ∼4 in the HRS, suggesting a strongly polarized medium in the LRS. The onset of F-N tunneling or TAT corresponds to an observed “overshoot” in the I-V response with an estimated threshold of 1.6 ± 0.2 V, in good agreement with reported electro-luminescence results for LRS devices. Resistive switching is discussed in terms of electrochemical reactions between common SiO2 defects, and specific defect energy levels are assigned to the dominant transitions in the I-V response. The overshoot response in the LRS is consistent with TAT through either the Eγ' oxygen vacancy or the hydrogen bridge defect, both of which are reported to have an effective bandgap of 1.7 eV. The SET threshold at ∼2.5 V is modeled as hydrogen release from the (Si-H)2 defect to generate the hydrogen bridge, and the RESET transition is modeled as an electrochemical reaction that re-forms (SiH)2. The results provide further insights into charge transport and help identify potential switching mechanisms in SiOx-based unipolar resistive switching memory.

Development and evaluation of a new rapid mold heating and cooling method for rapid heat cycle molding

A new rapid mold heating and cooling method is developed in this study. For rapid mold heating, cartridge heaters are assembled in the holes of the mold. Between the heaters and the corresponding mounting holes, there are annular gaps which are full of water. During mold heating, the heat generated by the heaters passes through the water gaps firstly and then transfers into mold base to raise cavity surface temperature. For rapid mold cooling, pressured cooling water is passed though the annular gaps. Firstly, a cell model was established to evaluate the effectiveness of the new rapid mold heating and cooling method. Thermal response analysis based on numerical simulations was conducted to investigate the influences of the gap size, the power density of the heaters and also the layout of heaters on thermal responses of the cavity surface. Further, the injection mold of a large LCD TV frame was designed and manufactured based on the developed rapid mold heating and cooling method. Both numerical simulations and experiments were performed to evaluate the thermal response efficiency of the cavity surface. The results show that the cavity surface temperature can be changed in a large temperature range within relatively short time. The simulation results are consistent well with the experimental results, which verifies the effectiveness of the established analysis method. Finally, production testing was conducted to produce the LCD TV panel. The results show that the weld marks on the outer surface can be eliminated completely and the outer surface gloss of the part can reach higher than 90GU with a molding cycle of about 60s. The consumption of energy and water can be greatly reduced by comparing with other conventional rapid mold heating and cooling methods.

Evaluating thermal comfort in mixed-mode buildings: A field study in a subtropical climate

To clarify the controversy about whether the adaptive comfort model is applicable in buildings with mechanical cooling systems operating in natural ventilation (NV) mode, we designed a longitudinal study in a mixed-mode (MM) building where mechanical air conditioning and natural passive cooling coexist in the same case building. Through statistical analysis of occupants' thermal responses during air conditioning (AC) and NV periods, considerable differences in occupants' perceived comfort were observed. The results show that occupants' actual thermal sensation and acceptance of thermal conditions both varied when the building changed from AC to NV mode, or vice versa. Compared to the steady-state comfort model (i.e., PMV), the adaptive model was found to be more applicable to MM buildings, especially when NV was being utilized. These findings provide support for a more flexible applicability of the adaptive comfort model in the real world, and can serve as a valuable reference for the design and operation of MM buildings.

Two-Dimensional Ablation and Thermal Response Analyses for Mars Science Laboratory Heat Shield

This paper examines transient simulations performed to predict in-depth thermal response and surface recession of the proposed heat shield material for the Mars Science Laboratory entry capsule, that is, phenolic impregnated carbon ablator. The finite volume material response code used in this paper solves the time-dependent governing equations, including energy conservation and a three-component decomposition model, with a surface energy-balance condition and a moving grid system to predict shape change due to surface recession. The predicted in-depth thermal response of heat shield material generally agrees well with the thermocouple data under various arcjet conditions. Also, two-dimensional computations using aerothermal environment for Mars entry (derived from a proposed three-sigma trajectory) are performed around the heat shield shoulder region, where high heating occurs as the result of angle of attack. Parametric studies are conducted to examine the effects of carbon-fiber orientation, material properties, and surface recession on heat shield bondline temperature history. It is proved that the fiber orientation configuration of the baseline heat shield has the lowest maximum bondline temperature.

Thermal signature of fear conditioning in mild post traumatic stress disorder

Fear conditioning has been proposed as an important factor involved in the etiology of posttraumatic stress disorder (PTSD). We examined fear processing in PTSD patients with mild symptoms and in individuals who did not develop symptoms (both groups consisting of victims of a bank robbery), through the study of fear-conditioned response. Conditioned responses were quantified by the skin conductance response (SCR) and the facial thermal response, the latter being measured by high-resolution functional thermal infrared (fIR) imaging.We found: (a) a change of the physiological parameters with respect to the baseline condition in both control subjects and PTSD patients during the conditioning phase; (b) the permanence of the conditioning effect in the maintenance phase in both control and PTSD patients; (c) patients and controls did differ for the variation across the phases of the physiological parameters rather than for their absolute values, showing that PTSD patients had a prolonged excitation and higher tonic component of autonomic activity. These results, although preliminary, indicate that the analysis of SCR and facial thermal response during the conditioning paradigm is a promising psychometric method of investigation, even in the case of low level of PTSD symptom severity. To the best of our knowledge, this study is the first attempt to discriminate between control subjects and PTSD patients with mild symptoms through infrared thermal imaging. It may suggest feasible approaches for diagnostic screening in the early phases of the disorder and in the assessment of preventive measures and therapies.

The genome sequence of the Antarctic bullhead notothen reveals evolutionary adaptations to a cold environment

Antarctic fish have adapted to the freezing waters of the Southern Ocean. Representative adaptations to this harsh environment include a constitutive heat shock response and the evolution of an antifreeze protein in the blood. Despite their adaptations to the cold, genome-wide studies have not yet been performed on these fish due to the lack of a sequenced genome. Notothenia coriiceps, the Antarctic bullhead notothen, is an endemic teleost fish with a circumpolar distribution and makes a good model to understand the genomic adaptations to constant sub-zero temperatures. We provide the draft genome sequence and annotation for N. coriiceps. Comparative genome-wide analysis with other fish genomes shows that mitochondrial proteins and hemoglobin evolved rapidly. Transcriptome analysis of thermal stress responses find alternative response mechanisms for evolution strategies in a cold environment. Loss of the phosphorylation-dependent sumoylation motif in heat shock factor 1 suggests that the heat shock response evolved into a simple and rapid phosphorylation-independent regulatory mechanism. Rapidly evolved hemoglobin and the induction of a heat shock response in the blood may support the efficient supply of oxygen to cold-adapted mitochondria. Our data and analysis suggest that evolutionary strategies in efficient aerobic cellular respiration are controlled by hemoglobin and mitochondrial proteins, which may be important for the adaptation of Antarctic fish to their environment. The use of genome data from the Antarctic endemic fish provides an invaluable resource providing evidence of evolutionary adaptation and can be applied to other studies of Antarctic fish.

Characterization and analysis of thermal response of rice husk for gasification applications

Present study involves characterisation and thermal analysis of rice husk as a potential source for gasification. Both the thermogravimetric (TG) analysis and differential scanning calorimetry were used to study the influence of heating rate on the degradation of rice husk. Experiments were carried out at three different heating rates of 10, 30, and 80 K min−1. The kinetic parameters, viz. pre-exponential factor, activation energy, and order of reaction were evaluated for both first and second reaction zones, which are categorized based on the degradation of cellulose, hemicelluloses, and lignin content present in the biomass. The degradation of mass with temperature obtained from TG curve was validated numerically. The thermal response of rice husk undergoing decomposition has also been modelled by using a one dimensional (1-D) transient thermal model with an nth order approximation for the rate of decomposition. Kinetic parameters, heat of decomposition, and thermal properties are taken as input to the model. The model was validated by measuring the transient temperature profiles during decomposition using Heisler chart at heat transfer coefficient of 20 W/m2 K. The data for specific heat and thermal conductivity of the biomass were taken from the literature and the values of heat of decomposition and kinetic parameters were taken from the experiments. Model results were compared well with the result obtained by using Heisler chart.

Finite difference analysis of thermal response and post-fire flexural degradation of glass fiber reinforced composites coated with carbon nanofiber based nanopapers

In this study, a 1D transient finite difference model was developed to predict the thermal response and post-fire flexural modulus degradation of glass fiber reinforced polyester composites subjected to various levels of heat flux. A carbon nanofiber (CNF) based hybrid nanopaper was coated onto the surface of the composites. The protective nanopaper coating was treated as to impose a temperature boundary condition in the model. A temperature dependent post-fire mechanical property model proposed in an earlier study was implemented with the thermal model in which the porosity and permeability of the material were taken into account. By comparing the post-fire residual flexural moduli, the model prediction showed reasonable agreement with the experimental data and expected physical behaviors. The model numerically demonstrates how the coating of nanopaper helps retain the structural integrity of the composite material, namely, the nanopaper coating leads to a reduction in mass loss, reduced cold side temperature, and eventually improved mechanical property. Furthermore, the parametric study of the model suggested that the porosity of the material has profound influence on the residual moduli of the composites.

Thermal Response Analysis and FE Modeling of Weapon

Thermal is a important factor that affect weapon firing accuracy and security in the process of weapon fire, so thermal analysis of weapon has important meaning . Aim at researched Weapon, the finite element model of the gun body was built, the temperature field of the gun body was calculated by FEM. The effects of temperature of the gun body on firer and aiming mechanism were also studied. Current research work will be helpful the weapon design

Numerical Analysis of Thermal Response of UHTCs under Aerodynamic Heating

Based on the theory and semi-empirical formulas, the surface heating flux of hypersonic flying vehicle under aerodynamic heating is calculated by using reference enthalpy method. On this basis, the thermal response of structure made of ultrahigh temperature ceramics(UHTCs) is simulated by using finite-element method. The results show that thermal stress shock is able to cause material to damage in a very short time

Thermal Response Analysis of Barrel of ISAW

Aim at Individual Soldier Automatic Weapon (ISAW), three-dimensional FE model and thermoelasticity coupling model of barrel were built. The coupling temperature field and coupling stress field of the barrel were calculated. Laws of the coupling temperature field and coupling stress field were obtained. The coupling temperature field and coupling stress field of different set of barrel aim at automatic fire were compared. The results show that the Material Properties of the barrel is security. Current research work will be helpful the Individual Soldier Automatic weapon design and the life of barrel study.

S191013 軽量アブレータの熱分解ガス内部流動と熱応答

Present study is introducing the thermal-response analysis and arc-heated wind tunnel experiments were carried out to study the effect of the pyrolysis gas flow inside the heating ablator. The analysis treated the heating process of arc-heater and the thermal-response analysis code included heat conduction, pyrolysis of resin, pyrolysis gas flow, and surface recession due to chemical reactions. In this study, the pyrolysis gas flow was treated as the multi-dimensional (axisymmetric) and unsteady phenomenon. This computation showed that the detailed analysis considering the multi-dimensional pyrolysis-gas flow and the flow injection of pyrolysis gas led to improvement of the predictive performance for the ablator thermal response. In addition, the temperature measurements inside and surface of the light-weight ablator were carried out It was used two type ablator in this experiment. As for one, surfaces were coated and the other was non-coated.