Combinatorial nanocalorimetry

2010 ◽  
Vol 25 (11) ◽  
pp. 2086-2100 ◽  
Author(s):  
Patrick J. McCluskey ◽  
Joost J. Vlassak
Keyword(s):  
Local Heating ◽  
Alloy System ◽  
Small Mass ◽  
Calorimetric Measurement ◽  
Heating Rates ◽  
Austenite Transformation ◽  
Silicon Nitride Membrane ◽  
The Individual ◽  
Silicon Based ◽  
Indium Film

The parallel nano-scanning calorimeter (PnSC) is a silicon-based micromachined device for calorimetric measurement of nanoscale materials in a high-throughput methodology. The device contains an array of nanocalorimeters. Each nanocalorimeter consists of a silicon nitride membrane and a tungsten heating element that also serves as a temperature gauge. The small mass of the individual nanocalorimeters enables measurements on samples as small as a few hundred nanograms at heating rates up to 104 K/s. The sensitivity of the device is demonstrated through the analysis of the melting transformation of a 25-nm indium film. To demonstrate the combinatorial capabilities, the device is used to analyze a Ni–Ti–Zr sample library. The as-deposited amorphous samples are crystallized by local heating in a process that lasts just tens of milliseconds. The martensite–austenite transformation in the Ni–Ti–Zr shape memory alloy system is analyzed and the dependence of transformation temperature and specific heat on composition is revealed.

Erratum: “Study on the Ordered Phases with Long Period in the Gold-Zinc Alloy System I. Survey of Crystal Structures and Calorimetric Measurement”

1961 ◽  
Vol 16 (1) ◽  
pp. 132A-132A ◽  
Author(s):  
Hiroshi Iwasaki ◽  
Makoto Hirabayashi ◽  
Kunio Fujiwara ◽  
Denjiro Watanabe ◽  
Shiro Ogawa
Keyword(s):  
Crystal Structures ◽  
Alloy System ◽  
Zinc Alloy ◽  
Calorimetric Measurement ◽  
Long Period ◽  
Ordered Phases

Hypersonic Viscous Shock Layer Calculation of Leeward Vortex-Induced Heat Transfer on a Sharp Cone at a High Angle of Attack

1977 ◽  
Vol 99 (2) ◽  
pp. 307-313 ◽  
Author(s):  
J. C. Adams
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Shock Layer ◽  
Vortex Flow ◽  
Local Heating ◽  
Three Dimensional ◽  
Leeward Side ◽  
Heating Rates ◽  
Viscous Shock Layer ◽  
Sharp Cone

An analysis technique applicable to the problem of leeward vortex-induced heat transfer on a sharp cone at high angles of incidence under hypersonic laminar flow conditions is presented. The analysis, a three-dimensional hypersonic viscous shock layer approach in conjunction with a numerical solution procedure, is shown to be both applicable and accurate based on comparisons of heat-transfer distributions, surface pressure distributions, and leeward meridian flow-field profile measurements taken in a hypersonic wind tunnel. Detailed calculations of the embedded vortex flow field on the leeward side of the cone are presented in such a manner as to clearly portray exactly how embedded vortex flow influences local heating rates.

scholarly journals Modelling of Thermal Decomposition Kinetics of Proteins, Carbohydrates and Lipids Using Scenedesmus microalgae thermal Data

2020 ◽  
Vol 32 (11) ◽  
pp. 2921-2926
Author(s):  
BOTHWELL NYONI ◽  
PHUTI TSIPA ◽  
SIFUNDO DUMA ◽  
SHAKA SHABANGU ◽  
SHANGANYANE HLANGOTHI
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Bulk Material ◽  
Decomposition Kinetics ◽  
Second Order ◽  
Thermal Decomposition Kinetics ◽  
Heating Rates ◽  
High Heating ◽  
The Individual ◽  
Kinetics Of

In present work, the thermal decomposition behaviour and kinetics of proteins, carbohydrates and lipids is studied by use of models derived from mass-loss data obtained from thermogravimetric analysis of Scenedesmus microalgae. The experimental results together with known decomposition temperature range values obtained from various literature were used in a deconvolution technique to model the thermal decomposition of proteins, carbohydrates and lipids. The models fitted well (R2 > 0.99) and revealed that the proteins have the highest reactivity followed by lipids and carbohydrates. Generally, the decomposition kinetics fitted well with the Coats-Redfern first and second order kinetics as evidenced by the high coefficients of determination (R2 > 0.9). For the experimental conditions used in this work (i.e. high heating rates), the thermal decomposition of protein follows second order kinetics with an activation energy in the range of 225.3-255.6 kJ/mol. The thermal decomposition of carbohydrate also follows second order kinetics with an activation energy in the range of 87.2-101.1 kJ/mol. The thermal decomposition of lipid follows first order kinetics with an activation energy in the range of 45-64.8 kJ/ mol. This work shows that the thermal decomposition kinetics of proteins, carbohydrates and lipids can be performed without the need of experimentally isolating the individual components from the bulk material. Furthermore, it was shown that at high heating rates, the decomposition temperatures of the individual components overlap resulting in some interactions that have a synergistic effect on the thermal reactivity of carbohydrates and lipids.

scholarly journals Flash Pyrolysis Kinetics of Extracted Lignocellulosic Biomass Components

2021 ◽  
Vol 9 ◽  
Author(s):  
Stefan Pielsticker ◽  
Benjamin Gövert ◽  
Kentaro Umeki ◽  
Reinhold Kneer
Keyword(s):  
Heating Rate ◽  
Molecular Structures ◽  
Small Scale ◽  
Drop Tube ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Flash Pyrolysis ◽  
Step Model ◽  
The Individual ◽  
Kinetics Of

Biomass is a complex material mainly composed of the three lignocellulosic components: cellulose, hemicellulose and lignin. The different molecular structures of the individual components result in various decomposition mechanisms during the pyrolysis process. To understand the underlying reactions in more detail, the individual components can be extracted from the biomass and can then be investigated separately. In this work, the pyrolysis kinetics of extracted and purified cellulose, hemicellulose and lignin are examined experimentally in a small-scale fluidized bed reactor (FBR) under N2 pyrolysis conditions. The FBR provides high particle heating rates (approx. 104 K/s) at medium temperatures (573–973 K) with unlimited reaction time and thus complements typically used thermogravimetric analyzers (TGA, low heating rate) and drop tube reactors (high temperature and heating rate). Based on the time-dependent gas concentrations of 22 species, the release rates of these species as well as the overall rate of volatiles released are calculated. A single first-order (SFOR) reaction model and a 2-step model combined with Arrhenius kinetics are calibrated for all three components individually. Considering FBR and additional TGA experiments, different reaction regimes with different activation energies could be identified. By using dimensionless pyrolysis numbers, limits due to reaction kinetics and heat transfer could be determined. The evaluation of the overall model performance revealed model predictions within the ±2σ standard deviation band for cellulose and hemicellulose. For lignin, only the 2-step model gave satisfying results. Modifications to the SFOR model (yield restriction to primary pyrolysis peak or the assumption of distributed reactivity) were found to be promising approaches for the description of flash pyrolysis behavior, which will be further investigated in the future.

Structural and compositional effects on the electron migration properties of Al-Cu alloy

1992 ◽  
Vol 50 (2) ◽  
pp. 1420-1421
Author(s):  
J.B. Liu ◽  
J.Z. Duan ◽  
R. Gronsky
Keyword(s):  
Integrated Circuits ◽  
Void Formation ◽  
Substrate Bias ◽  
Factors Affecting ◽  
Cu Alloy ◽  
Electron Migration ◽  
Service Application ◽  
The Individual ◽  
Silicon Based

Aluminium and aluminium-based alloys are typically used as the metallization interconnections in LSI and VLSI silicon-based integrated circuits. Important factors affecting the lifetime and reliability of these interconnections in IC devices are the individual microstructures, device layer combinations, electron migration, and stress migration that occur during their fabrication and their in-service application. There are many possible remedies for each of these factors. The use of bias sputtering or “planarization” has been shown to improve the quality of the interconnection greatly. Recently, some studies have revealed a new planarization technique involving sputter deposition of Al alloys at elevated temperature without any substrate bias, combined with a TiN precoating to reduce the migration of Al atoms. In this paper, the microstructure of Al-0.2Cu/TiN/SiO2/Si under optimum lifetime conditions is assessed, and a mechanism of void formation is proposed to explain the observations.A representative TEM cross section image of Al-0.2% Cu sputtered at 100 V bias and at substrate temperature 450°C with a TiN/SiO2 prercoating is shown in Fig.l. The surface topography of the Al-Cu alloy is shown for comparison purposes in Fig.2.

On the intergranular coupling in soft nanocrystalline materials

1996 ◽  
Vol 11 (2) ◽  
pp. 512-517 ◽  
Author(s):  
J. M. González ◽  
N. Murillo ◽  
J. González ◽  
J. M. Blanco ◽  
J. Echeberría
Keyword(s):  
Nanocrystalline Materials ◽  
Magnetocrystalline Anisotropy ◽  
Characteristic Length ◽  
Magnetic Moments ◽  
Bias Field ◽  
Continuous Heating ◽  
Heating Rates ◽  
Precursor Material ◽  
Magnetic Softness ◽  
The Individual

The magnetic softness of nanocrystalline materials prepared from amorphous precursors is attributed to the average of the local magnetocrystalline anisotropy of the individual crystallites. In the present paper we have studied the effective magnetic anisotropy of Fe-based nanocrystalline samples with different microstructures. These microstructures were produced by using different heating rates when crystallizing the precursor material by means of continuous heating treatments. From the results of our study of the magnetic properties of the samples, carried out from the measurement of the bias field dependence of the transverse susceptibility, it was possible to discern the occurrence of intergranular coupling and to evaluate the typical dimensions of the coupled units. Since these dimensions were larger than the characteristic length of the microstructure, we suggest that the enhancement of the soft properties is linked to the decrease of the microstructure-magnetization interactions originating in large units of coupled magnetic moments.

A Microreactor System for the Analysis of the Fast Pyrolysis of Biomass

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
Alexander Williams ◽  
J. Rhett Mayor
Keyword(s):  
Fast Pyrolysis ◽  
Heating Rates ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Study Results ◽  
Design Requirements ◽  
Layer Heating ◽  
The Individual ◽  
Pyrolysis Of Biomass ◽  
Good Agreement

A novel fast pyrolysis microreactor was developed to facilitate control over feedstock dwell time, pyrolysis temperature, and the individual collection of pyrolysis liquid and solid products. The design process followed is presented including design requirements, functional decomposition, commissioning tests, and the final microreactor design. A vibratory assisted spreading study was performed as particle agglomeration was a key challenge within the reactor design. The study results and analysis of variance are presented identifying the most significant factor and a best operating point. Analytical and experimental heat transfer analyses are also presented to validate the reactor’s thermal performance. Through the pairing of the analyses, projections for thin biomass layer heating rates are made resulting in estimates on the order of 400°C/s. Finally, experimental pyrolysis results are given showing fast pyrolysis conversion as a function of time and the process by which kinetic descriptors could be derived using this system’s results. Yield results are compared with literature and are found to be in good agreement with published fast pyrolysis results.

scholarly journals The effect of optically thin cirrus clouds on solar radiation in Camagüey, Cuba

2011 ◽  
Vol 11 (16) ◽  
pp. 8625-8634 ◽  
Author(s):  
B. Barja ◽  
J. C. Antuña
Keyword(s):  
Solar Radiation ◽  
Radiative Forcing ◽  
Near Infrared ◽  
Local Heating ◽  
Spectral Band ◽  
Solar Spectrum ◽  
Cirrus Clouds ◽  
Cloud Base ◽  
Cirrus Cloud ◽  
Heating Rates

Abstract. The effect of optically thin cirrus clouds on solar radiation is analyzed by numerical simulation, using lidar measurements of cirrus conducted at Camagüey, Cuba. Sign and amplitude of the cirrus clouds effect on solar radiation is evaluated. There is a relation between the solar zenith angle and solar cirrus cloud radiative forcing (SCRF) present in the diurnal cycle of the SCRF. Maximums of SCRF out of noon located at the cirrus cloud base height are found for the thin and opaque cirrus clouds. The cirrus clouds optical depth (COD) threshold for having double SCRF maximum out of noon instead of a single one at noon was 0.083. In contrast, the heating rate shows a maximum at noon in the location of cirrus clouds maximum extinction values. Cirrus clouds have a cooling effect in the solar spectrum at the Top of the Atmosphere (TOA) and at the surface (SFC). The daily mean value of SCRF has an average value of −9.1 W m−2 at TOA and −5.6 W m−2 at SFC. The cirrus clouds also have a local heating effect on the atmospheric layer where they are located. Cirrus clouds have mean daily values of heating rates of 0.63 K day−1 with a range between 0.35 K day−1 and 1.24 K day−1. The principal effect is in the near-infrared spectral band of the solar spectrum. There is a linear relation between SCRF and COD, with −30 W m−2 COD−1 and −26 W m−2 COD−1, values for the slopes of the fits at the TOA and SFC, respectively, in the broadband solar spectrum.

scholarly journals Net Exchange Reformulation of Radiative Transfer in the CO2 15-μm Band on Mars

2005 ◽  
Vol 62 (9) ◽  
pp. 3303-3319 ◽  
Author(s):  
Jean-Louis Dufresne ◽  
Richard Fournier ◽  
Christophe Hourdin ◽  
Frédéric Hourdin
Keyword(s):  
Radiative Transfer ◽  
Exchange Rates ◽  
General Framework ◽  
Matrix Representation ◽  
Local Heating ◽  
Computation Time ◽  
Heating Rates ◽  
Time Step ◽  
Radiative Fluxes ◽  
Numerical Instabilities

Abstract The net exchange formulation (NEF) is an alternative to the usual radiative transfer formulation. It was proposed by two authors in 1967, but until now, this formulation has been used only in a very few cases for atmospheric studies. The aim of this paper is to present the NEF and its main advantages and to illustrate them in the case of planet Mars. In the NEF, the radiative fluxes are no longer considered. The basic variables are the net exchange rates between each pair of atmospheric layers i, j. NEF offers a meaningful matrix representation of radiative exchanges, allows qualification of the dominant contributions to the local heating rates, and provides a general framework to develop approximations satisfying reciprocity of radiative transfer as well as the first and second principles of thermodynamics. This may be very useful to develop fast radiative codes for GCMs. A radiative code developed along those lines is presented for a GCM of Mars. It is shown that computing the most important optical exchange factors at each time step and the other exchange factors only a few times a day strongly reduces the computation time without any significant precision lost. With this solution, the computation time increases proportionally to the number N of the vertical layers and no longer proportionally to its square N 2. Some specific points, such as numerical instabilities that may appear in the high atmosphere and errors that may be introduced if inappropriate treatments are performed when reflection at the surface occurs, are also investigated.

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