Custom 1-D CFD Numeric Model of Single-Cell Scale Sample Holder for Scanning Thermal Analysis

2012 ◽  
Author(s):  
Logan M. Compton ◽  
James L. Armes ◽  
Gary L. Solbrekken
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Latent Heat ◽  
Thermoelectric Module ◽  
Experimental Results ◽  
Sample Holder ◽  
Current Profile ◽  
Scanning Calorimetry ◽  
Numeric Model

Successful cryopreservation protocols have been developed for a limited number of cell types through an extensive amount of experimentation. To optimize current protocols and to develop effective protocols for a larger range of cells and tissues it is imperative that accurate transport models be developed for the cooling process. Such models are dependent on the thermodynamic properties of intracellular and extracellular solutions, including heat capacity, latent heat, and the physical phase change temperatures. Scanning techniques, such as differential-scanning calorimetry (DSC) and differential thermal analysis are effective tools for measuring those thermodynamic properties. It is essential to understand the behavior of the in house fabricated differential-scanning calorimeter given different cooling and warming rates to reassure and validate the obtained experimental results. A 1-D transient CFD code was created in Matlab using Patankar’s theory to not only validate obtained experimental results but aid in optimizing the control system to produce linear cooling and warming rates. A freezing model was also implemented as a subroutine to numerically observe the effect of heat release and absorption of the sample during a run. The numeric model is composed of a multilayer scheme that incorporates a thermoelectric module which provides the primary temperature control along with the micron sized bridge with sample holder and thermocouple. An electric current profile is imported in from either an experimental run to validate results or from an optimization program to determine the optimum electrical current profile for a desired temperature profile. Numeric detection of heat capacity, latent heat, and thermal resistance has also been demonstrated.

Microfabrication of Single-Cell Scale Sample Holder for Scanning Thermal Analysis

2012 ◽  
Author(s):  
Logan M. Compton ◽  
James L. Armes ◽  
Gary L. Solbrekken
Keyword(s):  
Thermal Analysis ◽  
Thermodynamic Properties ◽  
Phase Change ◽  
Cell Types ◽  
Thermal Mass ◽  
Sample Holder ◽  
Measurement Sensitivity ◽  
Scanning Calorimetry ◽  
Measurement Signal ◽  
Manufacturing Techniques

Successful cryopreservation protocols have been developed for a limited number of cell types through an extensive amount of experimentation. To optimize current protocols and to develop more effective protocols for a larger range of cells and tissues it is imperative that accurate transport models be developed for the cooling process. Such models are dependent on the thermodynamic properties of intracellular and extracellular solutions, including heat capacity, latent heat, and the physical phase change temperatures. Scanning techniques, such as differential-scanning calorimetry (DSC) and differential thermal analysis (DTA), are effective tools for measuring those thermodynamic properties. Conventional thermal scanning tools require sample sizes that are multi-celled in nature. An issue with tools that require multiple cells is that the measurements effectively average the behavior of the cell sample, masking individual cell behavior. Further, extracellular solution further dismisses the desired measurement signal. It is hypothesized that evaluating thermodynamic properties of individual cells will allow more fundamental understanding of cell-level transport, and lead to more effective cryopreservation protocols. To detect a phase change within a prototypical mouse oocyte cell (∼100 μm diameter) sample holders for the scanning tools must be on the same order of size as the cell to reduce the relative thermal mass of the sample holder and to ultimately improve the measurement sensitivity. A proof-of-concept DTA sample holder with a ‘bowl’ to cradle the cell has been designed and fabricated using micro-electrical mechanical systems (MEMS) manufacturing techniques. Control software has been developed which is capable of providing any desired heating or cooling profile within a humidity controlled environment. Repeatable scans using water samples have been demonstrated.

scholarly journals Differential Scanning Calorimetry for Determining the Thermodynamic Properties of Selected Honeys

2015 ◽  
Vol 59 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jolanta Tomaszewska-Gras ◽  
Sławomir Bakier ◽  
Kamila Goderska ◽  
Krzysztof Mansfeld
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermodynamic Properties ◽  
Sugar Content ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Complete Liquefaction

Abstract Thermodynamic properties of selected honeys: glass transition temperature (Tg), the change in specifi c heat capacity (ΔCp), and enthalpy (ΔH) were analysed using differential scanning calorimetry (DSC) in relation to the composition i.e. water and sugar content. Glass transition temperatures (Tg) of various types of honey differed significantly (p<0.05) and ranged from -49.7°C (polyfloral) to -34.8°C (sunflower). There was a strong correlation between the Tg values and the moisture content in honey (r = -0.94). The degree of crystallisation of the honey also influenced the Tg values. It has been shown that the presence or absence of sugar crystals influenced the glass transition temperature. For the decrystallised honeys, the Tg values were 6 to 11°C lower than for the crystallised honeys. The more crystallised a honey was, the greater the temperature difference was between the decrystallised and crystallized honey. In conclusion, to obtain reliable DSC results, it is crucial to measure the glass transition after the complete liquefaction of honey.

Heat Capacity and Thermodynamic Properties of LaBr3 at 300 – 1100 K

2004 ◽  
Vol 59 (11) ◽  
pp. 825-828
Author(s):  
L. Rycerz ◽  
E. Ingier-Stocka ◽  
B. Ziolek ◽  
S. Gadzuric ◽  
M. Gaune-Escard
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
Enthalpy Of Formation ◽  
Thermodynamic Functions ◽  
Molar Enthalpy ◽  
Standard Molar Enthalpy ◽  
Scanning Calorimetry ◽  
Temperature Range

The heat capacity of solid and liquid LaBr3 was measured by Differential Scanning Calorimetry (DSC) in the temperature range 300 - 1100 K. The obtained results were fitted by a polynomial temperature dependence. The enthalpy of fusion of LaBr3 was also measured. By combination of these results with the literature data on the entropy, S0m (LaBr3, s, 298.15 K) and the standard molar enthalpy of formation, ΔformH0m (LaBr3, s, 298.15 K), the thermodynamic functions of lanthanum tribromide were calculated up to 1300 K

scholarly journals Высокотемпературная теплоемкость германатов Pr-=SUB=-2-=/SUB=-Ge-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- и Nd-=SUB=-2-=/SUB=-Ge-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- в области 350-1000 K

2018 ◽  
Vol 60 (3) ◽  
pp. 618
Author(s):  
Л.Т. Денисова ◽  
Л.А. Иртюго ◽  
В.В. Белецкий ◽  
Н.В. Белоусова ◽  
В.М. Денисов
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Temperature Effect ◽  
Molar Heat Capacity ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Scanning Calorimetry ◽  
Phase Synthesis

AbstractPr2Ge2O7 and Nd2Ge2O7 were obtained via solid-phase synthesis from Pr2O3 ( Nd2O3 ) and GeO2 with multistage firing in air within 1273–1473 K. A temperature effect on molar heat capacity of the oxide compounds was measured with a differential scanning calorimetry. Their thermodynamic properties were calculated from the C _ P = f ( T ) dependences.

Étude thermodynamique des trois isomères de l'acide hydroxybenzoïque

1993 ◽  
Vol 71 (9) ◽  
pp. 1378-1383 ◽  
Author(s):  
Raphaël Sabbah ◽  
Thi Huy Duc Le
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Differential Thermal Analysis ◽  
Thermodynamic Study ◽  
Experimental Results ◽  
Ortho Isomer ◽  
Resonance Energies ◽  
Hydroxybenzoic Acids ◽  
Heat Capacity Measurements ◽  
Good Agreement

A thermodynamic study of the three hydroxybenzoic acids was carried out by combustion and sublimation calorimetry, heat capacity measurements, and differential thermal analysis. The experimental results (in kJ mol−1) are summarized as:[Formula: see text]From these experimental results, it was possible to determine for the three isomers (i) the resonance energies. From their comparison, the ortho isomer seems to be the most stable. This result is discussed using a structural consideration; (ii) the enthalpies of atomization. These values are in good agreement with that calculated using a contribution method.

scholarly journals Long-Term Physical Aging Tracked by Advanced Thermal Analysis of Poly(N-Isopropylacrylamide): A Smart Polymer for Drug Delivery System

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3810
Author(s):  
Anna Czerniecka-Kubicka ◽  
Iwona Zarzyka ◽  
Marek Pyda
Keyword(s):  
Drug Delivery ◽  
Thermal Analysis ◽  
Heat Capacity ◽  
Glass Transition ◽  
Physical Aging ◽  
Amorphous Polymer ◽  
Recovery Process ◽  
Scanning Calorimetry ◽  
Smart Polymer ◽  
Structural Recovery

Poly(N-isopropylacrylamide) (PNIPA), as a smart polymer, can be applied for drug delivery systems. This amorphous polymer can be exposed on a structural recovery process during the storage and transport of medicaments. For the physical aging times up to one year, the structural recovery for PNIPA was studied by advanced thermal analysis. The structural recovery process occurred during the storage of amorphous PNIPA below glass transition and could be monitored by the differential scanning calorimetry (DSC). The enthalpy relaxation (recovery) was observed as overshoot in change heat capacity at the glass transition region in the DSC during heating scan. The physical aging of PNIPA was studied isothermally at 400.15 K and also in the non-isothermal conditions. For the first time, the structural recovery process was analyzed in reference to absolute heat capacity and integral enthalpy in frame of their equilibrium solid and liquid PNIPA.

Austenite Phase Transformation of Thermal Analysis

2011 ◽  
Vol 291-294 ◽  
pp. 786-789
Author(s):  
Lian Sheng Chen ◽  
Yan Hong Leng ◽  
Yan Kai Han ◽  
Jin Ying Song
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Heat Capacity ◽  
Phase Transformation ◽  
Cooling Rate ◽  
Latent Heat ◽  
Austenite Phase ◽  
Cooling Process ◽  
Continuous Cooling ◽  
Metal Material

In the continuous cooling process, when the metal material austenite transition occurs, latent heat is released. Through the thermal-meter can determine the characteristics point of the phase transition. In this paper, by thermal analysis, at the cooling rate of 0.5°C•s-1, 0.8°C•s-1, 40Cr bar is tested to determine the characteristics point of the phase transition, latent heat and the heat capacity in phase transition.

scholarly journals Thermo-physical Investigations of oils, N-(2-aminoethyl)oleamide and Resulting Gels using TGA-DSC

2021 ◽  
Vol 37 (6) ◽  
pp. 1496-1500
Author(s):  
Narendra S. Joshi ◽  
Govinda P. Waghulde ◽  
Gaurav R. Gupta
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Constant Pressure ◽  
Analysis Data ◽  
Thermal Analysis Data ◽  
Scanning Calorimetry ◽  
Tga Analysis

Edible vegetable oils were gelled by using N-(2-aminoethyl)-oleamide. Oils in their free state were subjected to differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analysis. The gels of these oils were prepared by using N-(2-aminoethyl)-oleamide as gelator and similar thermal analysis of the gels was carried out. The thermal analysis data obtained was used to determine specific heat capacity at constant pressure (Cp). The values were compared with the reported values of heat capacities. It is observed that the thermal properties and transitions of oils and gels, specific heat capacity is helpful parameter to understand the fundamentals of gels and gelation strategies.

scholarly journals Simulation of IR Heating for Composite Stamping

2013 ◽  
Vol 554-557 ◽  
pp. 1523-1529 ◽  
Author(s):  
Abdelmagid El Bakali ◽  
Olivier de Almeida ◽  
Jérôme Bikard ◽  
Maxime Villière ◽  
Fabrice Schmidt ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Thermal Properties ◽  
Measurement Techniques ◽  
Experimental Results ◽  
Infrared Heating ◽  
Back Side ◽  
Scanning Calorimetry ◽  
Melt Temperature ◽  
Dsc Measurements ◽  
Ir Heating

Composite stamping is a two steps process that includes an infrared heating oven in order to melt the composite sheets before forming. This study deals with the numerical simulation of the heating step of the process. The numerical model has been validated using three woven glass and carbon / PA6.6 composites provided by Solvay Rhodia. This type of simulation consists in solving the heat equation with a radiative flux that characterizes the interaction of the material with the IR heating. The model thus considers the IR properties of the material (emission and reflexion). Considering a homogeneous composite, the optical and thermal properties of sheets have been first measured. The material’s emissivity has been measured using a FTIR spectrometer from the reflective and transmitive spectra, by using the Kirchoff law and considering a Lambertian material. Three complementary measurement techniques were used to determine the thermal properties of the composites. Differential Scanning Calorimetry (DSC) measurements have been performed to identify the heat capacity of the composites. On another hand, a hot disc system (measurements performed at the LTN, France) has been used in transient conditions to determine the heat capacity and the thermal conductivity of the composites is all three directions. Finally, the in-plane thermal matrix of conductivity has also been measured by thermography by using an inverse method. The simulation of composites heating has been performed with Comsol MultiphysicsTM and the simulation procedure was validated by comparison with experimental results. The simulated IR oven is composed of 9 IR emittors provided by Toshiba Lighting Company that emit mainly in short IR wavelength (0.75-2µm). The emission properties of the tungsten filament were implemented in order to simulate the IR heating. Free convective heat transfer was also taken into account in the oven. In order to validate the model, an experimental set-up was instrumented with a calibrated IR pyrometer that measured the back side of the heated composite sheets. The experimental results confirm a low thermal gradient through composite thickness, in particular for carbon-reinforced composite. This result is consistent with the low Biot number of the composites. Moreover, experimental and simulated temperatures are in good agreement with an error lower than 15% in the entire heating stage from room to melt temperature.

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