Thermal Response in Crystalline Iβ Cellulose:  A Molecular Dynamics Study

2007 ◽  
Vol 111 (30) ◽  
pp. 9138-9145 ◽  
Author(s):  
Malin Bergenstråhle ◽  
Lars A. Berglund ◽  
Karim Mazeau
Keyword(s):  
Molecular Dynamics ◽  
Thermal Response

Atomistic molecular dynamics study to investigate thermal response of cellulose nanofibrils using GROMACS

2018 ◽  
Author(s):  
Jaehwan Kim ◽  
Md Imrul Reza Shishir ◽  
Ruth Mwongeli Muthoka ◽  
Hyun Chan Kim ◽  
Jung Woong Kim
Keyword(s):  
Molecular Dynamics ◽  
Cellulose Nanofibrils ◽  
Thermal Response

A molecular dynamics study of the thermal response of crystalline cellulose Iβ

Cellulose ◽  
2011 ◽  
Vol 18 (2) ◽  
pp. 207-221 ◽  
Author(s):  
Qiong Zhang ◽  
Vincent Bulone ◽  
Hans Ågren ◽  
Yaoquan Tu
Keyword(s):  
Molecular Dynamics ◽  
Thermal Response ◽  
Crystalline Cellulose ◽  
Cellulose Iβ

scholarly journals Colossal barocaloric effects in the complex hydride Li$$_{2}$$B$$_{12}$$H$$_{12}$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kartik Sau ◽  
Tamio Ikeshoji ◽  
Shigeyuki Takagi ◽  
Shin-ichi Orimo ◽  
Daniel Errandonea ◽  
...  
Keyword(s):  
Phase Transition ◽  
Molecular Dynamics ◽  
Electronic Device ◽  
Thermal Response ◽  
Reorientational Motion ◽  
Promising Alternative ◽  
Temperature Changes ◽  
Energy Material ◽  
Dynamics Simulations ◽  
Solid State Cooling

AbstractTraditional refrigeration technologies based on compression cycles of greenhouse gases pose serious threats to the environment and cannot be downscaled to electronic device dimensions. Solid-state cooling exploits the thermal response of caloric materials to changes in the applied external fields (i.e., magnetic, electric and/or mechanical stress) and represents a promising alternative to current refrigeration methods. However, most of the caloric materials known to date present relatively small adiabatic temperature changes ($$|\Delta T| \sim 1$$ | Δ T | ∼ 1 to 10 K) and/or limiting irreversibility issues resulting from significant phase-transition hysteresis. Here, we predict by using molecular dynamics simulations the existence of colossal barocaloric effects induced by pressure (isothermal entropy changes of $$|\Delta S| \sim 100$$ | Δ S | ∼ 100  J K$$^{-1}$$ - 1 kg$$^{-1}$$ - 1 ) in the energy material Li$$_{2}$$ 2 B$$_{12}$$ 12 H$$_{12}$$ 12 . Specifically, we estimate $$|\Delta S| = 367$$ | Δ S | = 367  J K$$^{-1}$$ - 1 kg$$^{-1}$$ - 1 and $$|\Delta T| = 43$$ | Δ T | = 43  K for a small pressure shift of P = 0.1 GPa at $$T = 480$$ T = 480  K. The disclosed colossal barocaloric effects are originated by a fairly reversible order–disorder phase transformation involving coexistence of Li$$^{+}$$ + diffusion and (BH)$$_{12}^{-2}$$ 12 - 2 reorientational motion at high temperatures.

scholarly journals Thermal Response in Cellulose Iβ Based on Molecular Dynamics

2019 ◽  
Vol 7 (1) ◽  
pp. 85-97
Author(s):  
Xuewei Jiang ◽  
Yu Chen ◽  
Yue Yuan ◽  
Lu Zheng
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
High Temperatures ◽  
Structural Information ◽  
Structural Parameters ◽  
Thermal Response ◽  
Intermediate Temperature ◽  
Cellulose I ◽  
Cellulose Iβ ◽  
Dynamics Simulations

AbstractThe structural details of cellulose I β were discussed according to molecular dynamics simulations with the GLYCAM-06 force field. The simulation outcomes were in agreement with previous experimental data, including structural parameters and hydrogen bond pattern at 298 K. We found a new conformation of cellulose Iβ existed at the intermediate temperature that is between the low and high temperatures. Partial chain rotations along the backbone direction were found and conformations of hydroxymethyl groups that alternated from tg to either gt or gg were observed when the temperature increased from 298 K to 400 K. In addition, the gg conformation is preferred than gt. For the structure adopted at high temperature of 500 K, major chains were twisted and two chains detached from each plain. In contrast to the observation under intermediate temperature, the population of hydroxymethyl groups in gt exceeded that in gg conformation at high temperature. In addition, three patterns of hydrogen bonding were identified at low, intermediate and high temperatures in the simulations. The provided structural information indicated the transitions occurred around 350 K and 450 K, considered as the transitional temperatures of cellulose Iβ in this work.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

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