scholarly journals Reverse heat flow with Peltier-induced thermoinductive effect

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kenjiro Okawa ◽  
Yasutaka Amagai ◽  
Hiroyuki Fujiki ◽  
Nobu-Hisa Kaneko
Keyword(s):  
Exact Solution ◽  
Heat Flow ◽  
Thermal Inertia ◽  
Peltier Effect ◽  
Local Cooling ◽  
High Temperature Side ◽  
Inductive Component ◽  
Ac Current ◽  
Single Material ◽  
Temperature Side

AbstractThe concept of “thermal inductance” expands the options of thermal circuits design. However, the inductive component is the only missing components in thermal circuits unlike their electromagnetic counterparts. Herein, we report an electrically controllable reverse heat flow, in which heat flows from a low-temperature side to a high-temperature side locally and temporarily in a single material by imposing thermal inertia and ac current. This effect can be regarded as an equivalent of the “thermoinductive” effect induced by the Peltier effect. We derive the exact solution indicating that this reverse heat flow occurs universally in solid-state systems, and that it is considerably enhanced by thermoelectric properties. A local cooling of 25 mK is demonstrated in (Bi,Sb)2Te3, which is explained by our exact solution. This effect can be directly applicable to the potential fabrication of “thermoinductor” in thermal circuits.

scholarly journals Reverse Heat Flow with Peltier-Induced Thermoinductive Effect

2021 ◽  
Author(s):  
Kenjiro Okawa ◽  
Yasutaka Amagai ◽  
Hiroyuki Fujiki ◽  
Nobu-Hisa Kaneko
Keyword(s):  
Thermal Conductivity ◽  
Exact Solution ◽  
Solid State ◽  
Heat Flow ◽  
Negative Temperature ◽  
Peltier Effect ◽  
Local Cooling ◽  
Heating And Cooling ◽  
Inductive Component ◽  
Ac Current

Abstract The inductive component is the only missing components in thermal circuits unlike their electromagnetic counterparts. Herein, we report an electrically controllable reverse heat flow, which can be regarded as a proper equivalent of the “thermoinductive” effect. The underlying concept is the heating and cooling of the ends of the material by the Peltier effect under an applied ac current; this form a negative temperature gradient in the opposite direction in a controllable manner. We have derived the exact solution indicating that this reverse heat flow occurs universally in solid-state systems, even in conventional metallic Cu, and that it is considerably enhanced by thermoelectric properties (i.e., a large Seebeck coefficient and low thermal conductivity). A local cooling of 25 mK was demonstrated in (Bi,Sb)2Te3, which was explained by our exact solution. This electrically controlled reverse heat flow is directly applicable to the fabrication of a “thermoinductor” in thermal circuits.

Search for High Damping Metallic Glasses

2006 ◽  
Vol 319 ◽  
pp. 151-156 ◽  
Author(s):  
Y. Hiki ◽  
M. Tanahashi ◽  
Shin Takeuchi
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Internal Friction ◽  
Metallic Glass ◽  
Room Temperature ◽  
Temperature Stability ◽  
Temperature Peak ◽  
High Temperature Side ◽  
Side Slope ◽  
Temperature Side

In a hydrogen-doped metallic glass, there appear low-temperature and high-temperature internal friction peaks respectively associated with a point-defect relaxation and the crystallization. The high-temperature-side slope of low-temperature peak and also the low-temperature-side slope of high-temperature peak enhance the background internal friction near the room temperature. A hydrogen-doped Mg-base metallic glass was proposed as a high-damping material to be used near and somewhat above the room temperature. Stability of the high damping was also checked.

Moisture-dependent orthotropic viscoelastic properties of Chinese fir wood during quenching in the temperature range of 20 to −120°C

Holzforschung ◽  
2019 ◽  
Vol 74 (1) ◽  
pp. 10-19 ◽  
Author(s):  
Zhu Li ◽  
Jiali Jiang ◽  
Jianxiong Lyu
Keyword(s):  
Cell Wall ◽  
Viscoelastic Properties ◽  
Wood Cell Wall ◽  
Bound Water ◽  
Free Water ◽  
Chinese Fir ◽  
High Temperature Side ◽  
Temperature Spectrum ◽  
Β Relaxation ◽  
Temperature Side

AbstractAn understanding of wood’s moisture-dependent viscoelastic properties under various temperature conditions is important for assessing its utilization and product quality. In this study, we investigated the influence of moisture content (MC) on the orthotropic viscoelasticity of Chinese fir wood (Cunninghamia lanceolata [Lamb.] Hook.) during quenching ranging from 20 to −120°C. The storage modulus (E′) and loss factor (tan δ) of the longitudinal (L), radial (R) and tangential (T) specimens were determined for nine MC levels ranging from 0.6 to 60.0%. The results showed that E′ generally decreased with increasing amount of bound water in all orthotropic directions, regardless of the temperature. In contrast, a sharp increase in E′ was observed at temperatures below 0°C when free water was present, due to the formation of ice within the cell lumens. The γ-relaxation and β-relaxation were observed in the temperature spectrum. A comparison demonstrates that the β-relaxation showed evident grain orientation. When only bound water was present in the wood cell wall, one clear γ-relaxation was found for all orthotropic directions. In contrast, only the high-temperature side of the γ-relaxation was observed in the three anatomic directions in specimens with free water, which might be related to the amorphous wood cell wall coupling with the frozen free water during the quenching process. In addition, the differences in peak temperatures of the γ-relaxation among the three main directions diminished with increasing bound water.

Tourmaline and boron as indicators of the presence, segregation and extraction of melt in pelitic migmatites: examples from the Ryoke metamorphic belt, SW Japan

2004 ◽  
Vol 95 (1-2) ◽  
pp. 111-123 ◽  
Author(s):  
Tetsuo Kawakami
Keyword(s):  
High Temperature ◽  
Partial Melting ◽  
Correct Recognition ◽  
High Temperature Side ◽  
Metamorphic Belt ◽  
Melt Extraction ◽  
Mode Of Occurrence ◽  
Temperature Side ◽  
Sw Japan

The mode of occurrence of borosilicates and the breakdown fronts of prograde tourmaline (tourmaline-out isograd) in three anatectic migmatite regions of the Ryoke metamorphic belt, SW Japan, are reported. The breakdown of tourmaline in the migmatite zones and release of boron into the melts, followed by the extraction of the boron-bearing melts from the migmatite zones occurred throughout the Ryoke metamorphic belt. Retrograde, magmatic tourmaline in interboudin partitions filled with leucosome is useful for calculating the degree of partial melting in the migmatites. Using boron contents in the leucosomes and pelitic schists, the degree of partial melting at the migmatite front of the Aoyama area is estimated to be 12 wt.%. Extraction of the boron-bearing melt is suggested by the boron-depleted nature of the migmatites. Connection of boudinage structures probably supplied the vertical pathways of the segregated melts, and major transport of the melts was accomplished by dyking. Irregularly shaped, amoeboid tourmaline locally occurs on the high-temperature side of the tourmaline-out isograds in the Yanai and Komagane areas, implying incomplete extraction of boron-bearing melts from those areas. Discriminating retrograde from prograde tourmaline enables correct recognition of the tourmaline-out isograd. The amount of retrograde tourmaline in migmatites can potentially be used as an indicator of the degree of melt extraction from them.

scholarly journals Reconfigurable Single-Material Peltier Effect Using Magnetic-Phase Junctions

2021 ◽  
Author(s):  
Kurea Nakagawa ◽  
Tomoyuki Yokouchi ◽  
Yuki Shiomi
Keyword(s):  
Magnetic Transition ◽  
Peltier Effect ◽  
First Order ◽  
Heating And Cooling ◽  
Simulation Based ◽  
Semiconductor Junction ◽  
Peltier Device ◽  
Modular Structures ◽  
Junction Structure ◽  
Single Material

Abstract Peltier effects, which produce a heat flux at the junction of two different materials, have been an important technology for heating and cooling by electrical means. Whereas Peltier devices have advantages such as cleanliness, silence, compactness, flexibility, reliability, and efficiency, relatively complicated modular structures are unavoidable, leading to a higher cost than that of commonly used refrigeration technology. Here, we provide a concept of a Peltier device composed of a single magnetic material exhibiting a first-order magnetic transition. Our concept is based on a controllable junction structure consisting of two magnetic phases with opposite Peltier coefficients instead of a semiconductor junction. Using Mn1.96Cr0.04Sb samples with the first-order magnetic transition between ferrimagnetic (FI) and antiferromagnetic (AF) states, we successfully made a stable junction structure of AF/FI/AF by a pulse heating method and achieved a maximum Peltier coefficient of 0.58 mV. Our device concept was further verified by a numerical simulation based on a finite element method. The single-material Peltier effect reported here avoids a complex device design involving material junctions and is importantly reconfigurable.

scholarly journals An Analytical and Experimental Evaluation of a Heat Sink Under Constant Heat Flow and Forced Convection Heat Transfer

2021 ◽  
Vol 53 (4) ◽  
pp. 210405
Author(s):  
Ehsan Fadhil Abbas
Keyword(s):  
Exact Solution ◽  
Heat Flow ◽  
Heat Sink ◽  
Experimental Result ◽  
Maximum Temperature ◽  
Average Error ◽  
Airflow Rate ◽  
Convection Heat ◽  
Constant Heat ◽  
Error Ratio

In this study, the exact transient differential equation was used to calculate the convection heat loss in a heat sink with a rectangular cross section fin. The result of the analytic solution was compared to the result from experiments conducted on a standard heat sink. The experiments were performed at a constant heat flow of 9000 W/m2 and a low airflow rate ranging from 12 to 100 cm3/s in seven steps. The comparative results showed that while there was good agreement between the experimental result and the exact solution, the average error ratio increased with an increase of the airflow rate. However, the maximum average error ratio between the experimental result and the exact solution did not exceed 6.4%. The maximum temperature distribution in the heat sink was obtained at a time of 900 s in all experiments.

Downhole Measurements of Thermal Conductivity in Geothermal Reservoirs

1977 ◽  
Vol 99 (4) ◽  
pp. 607-611 ◽  
Author(s):  
H. D. Murphy ◽  
R. G. Lawton
Keyword(s):  
Thermal Conductivity ◽  
Exact Solution ◽  
Heat Flow ◽  
Thermal Contact ◽  
Approximate Solutions ◽  
Laboratory Measurements ◽  
Transient Effect ◽  
Transient Heat Flow ◽  
Geothermal Wells ◽  
Downhole Measurements

The line source method of determining thermal conductivity is extended to include the transient effect associated with the fluid in flowing geothermal wells. The general equations describing transient heat flow are utilized. Approximate solutions are derived and compared to the exact solution of the general equations. The proposed method is operationally simple since the heater, and the associated problems of obtaining adequate thermal contact between the heater and the sides of the borehole are eliminated. Using this method downhole measurements were obtained and favorably compared with laboratory measurements on characterized core specimens taken from wells in a hot dry rock geothermal reservoir.

SPECIFIC HEAT ANOMALY FOR H ≥ 28.5 T IN CeIrIn5

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3014-3017
Author(s):  
J. S. KIM ◽  
J. ALWOOD ◽  
P. KUMAR ◽  
G. R. STEWART
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Specific Heat ◽  
Single Crystals ◽  
Hybrid Magnet ◽  
High Temperature Side ◽  
And Shifts ◽  
Temperature Side

Recently Takeuchi reported a weak, 'metamagnetic-like' increase in the magnetization around 42 T in single crystals of CeIrIn 5 for field in the c-direction. We report specific heat measurements on single crystal CeIrIn 5, H parallel c-axis, measured in the dc hybrid magnet at NHMFL in Tallahassee between 1.4 and 10 K. A clear anomaly in C/T in 35 T is observed to peak at 1.8 K, with an entropy of 6% of RIn2. This anomaly grows in size and shifts upwards in temperature (both monotonically) with increasing H until at 45 T T peak =4.1 K , with the entropy associated with the transition equal to 14% of RIn2. C/T data at 32 T show3 only the high temperature side of the peak occurring above 1.4 K, while C/T data at 28.5 T show no anomaly down to 1.4 K. This is consistent with our Tpeak vs H data, which imply T peak → 0 at 26 T.

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