Papers by Charles Earnest
Thermo
The results obtained from a study of the thermal transformations of polymorphic long-chain normal... more The results obtained from a study of the thermal transformations of polymorphic long-chain normal paraffins (n-C32H66 and n-C36H74) are presented here. The research was performed using a power-compensated Differential Scanning Calorimeter (DSC). Both heating and cooling experiments were performed in dynamic nitrogen atmosphere. Thermodynamic data for both polymorphic transitions, as well as the fusion endotherms, were determined from the DSC thermal curves. Using the heats of transition (∆H), in Joules/gram, obtained from the data in the DSC thermal curves, molar heats of transition (∆H), in kJ/mol, were calculated and compared to previously published values. The molar entropy of transition (∆S) was then calculated for each of the observed thermal events. Additional information is given by the author on obtaining the best results from the use of DSC for the thermal behavior of n-paraffins. This manuscript opens with a review of most of the early work and the results it provided deal...
In this study, modem simultaneous thermal analysis instrumentation is employed to obtain valuable... more In this study, modem simultaneous thermal analysis instrumentation is employed to obtain valuable thermal response behavior of a three primary component porcelain ceramic formulation containing kaolinite, feldspar, and silica. The silica component consisted of both crystalline quartz and amorphous silica. The thermal analysis data obtained in this study provide information related to the behavior of the raw materials in the mixture during the firing of the formulation to produce the porcelain product. The types of thermal analysis data obtained in this study were differential thermal analysis (DTA), thermogravimetry (TG or TGA), and derivative thermogravimetry (DTG). These data were obtained experimentally in our laboratory using a single computerized simultaneous thermal analysis (STA) instrument.
Advances in Applied Chemistry and Biochemistry, 2018
The major source of alumina is from bauxite ores. Bauxite ores are not pure clay mineral species ... more The major source of alumina is from bauxite ores. Bauxite ores are not pure clay mineral species but are composed of a mixture of mineral components. The components and amounts vary with location. The main aluminous components found in bauxite ores are gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)). These may occur individually or as mixtures of these components. This study offers an improved approach to the quantification of the gibbsite component in naturally occurring bauxite ores using the thermal method of analysis known as either Thermogravimetry (TG) or Thermogravimetric Analysis (TGA). The methodology used in this study involves the use of an experimentally determined empirical gravimetric factor, G, rather than the theoretical factor based on the stoichiometric equation for the complete dehydroxylation of gibbsite.
Thermochimica Acta, 1983
The thermal behavior of the SHCa-1 hectorite source clay specimen was studied by the technique of... more The thermal behavior of the SHCa-1 hectorite source clay specimen was studied by the technique of computerized differential thermal analysis (DTA) using dynamic nitrogen, dynamic air, dynamic carbon dioxide, and static air atmospheres. The atmospheric dependence of the DTA thermal curves was established. A series of samples heated in dynamic nitrogen purge was analyzed by X-ray diffraction spectrographic techniques to establish the high temperature phases of the SHCa-1 (carbonate-contaminated) hectorite specimen. Differential thermal analysis was also performed on a processed (carbonate-cleaned) hectorite specimen using dynamic nitrogen atmosphere. Additional TG-DTG thermal curves were included in this portion of the study.
Thermochimica Acta, 1983
Several hectorite speciments representing both raw carbonate bearing ores and processed hectorite... more Several hectorite speciments representing both raw carbonate bearing ores and processed hectorite (carbonate-cleaned) specimens were analyzed by the computerized thermogravimetric techniques of TG and DTG. The results of these thermogravimetric investigations combined with the results of automated acid evolved carbonate determinations and plasma emission spectroscopy were employed to gain new insights to both the composition and thermal behavior of both raw hectorite ores and carbonate-cleaned hectorite clay mineral specimens.
Journal of Thermal Analysis and Calorimetry, 2017
A study of the thermal behavior of both barium and strontium carbonates was performed in dynamic ... more A study of the thermal behavior of both barium and strontium carbonates was performed in dynamic argon atmosphere over a wide range of temperatures. Both barium and strontium carbonates are white crystalline powders at room temperature. These compounds undergo reversible polymorphic transitions from the orthorhombic to hexagonal crystal forms when heated to temperatures above 800 °C. On further heating, the barium carbonate undergoes an additional polymorphic transition where the hexagonal form transforms to a face-centered cubic form near 976 °C. On continued heating, this cubic form of barium carbonate decomposes to barium oxide liberating carbon dioxide gas. Strontium carbonate, on the other hand, tends to be thermally less stable than barium carbonate. It is reported to lose mass over a broad range of temperatures beginning below the observed polymorphic transition (Charsley et al. in J Therm Anal Calorim 40:1415–1422, 1993). Our studies, using both differential thermal analysis (DTA) and thermogravimetric analysis techniques, attempt to answer questions of uncertainty of the reported temperatures of transition, as well as heats of transition, for these industrially important compounds. As a result of these findings, recommendations are given for the use of these compounds as reference standards for calibration of DTA instruments.
Thermochimica Acta, 1984
... ACKNOWLEDGMENTS The author would like to express his sincere appreciation to FI Fiene for bot... more ... ACKNOWLEDGMENTS The author would like to express his sincere appreciation to FI Fiene for both the low temperature ash specimens and supporting XRD results. ... Haw-Jye Shyu, PO Vaishnava, and PA Montano, Fuel, 60 (1981) 1022-1026. ...
1983 EIC 6th Electrical/Electronical Insulation Conference, 1983
The world-wide electronics market approached approximately $150 billion in 1982. Leading the adva... more The world-wide electronics market approached approximately $150 billion in 1982. Leading the advances are the computer, communication, and instrument products. In addition, there is a huge market for electrical conductors, components, and wire and cable. The producers of the products, and indeed many more, are all concerned with the characterization, reliability and quality control of the many diverse components that make up an electronics package. These components include printed circuit boards, integrated circuits, resistors, connectors, solders and conductors, among many others.
ASTM special technical publications, 1988
Thermogravimetry (TG) is an analytical technique that monitors the mass of a substance as it is s... more Thermogravimetry (TG) is an analytical technique that monitors the mass of a substance as it is subjected to a controlled temperature program. TG is the modern day frontier of the much older and well-established techniqueof gravimetry. Although many compositional analyses may be performed by conventional gravimetry, thermogravimetry offers a more rapid method because of the smaller sample size and faster heating rates. Thus, special instrumentation requirements are imposed on the more modern, rapid, and automated thermogravimetric method. Many commercial TG systems are available. The major difference in these are in the furnace (size, design, and positioning with respect to the furnace tube and sample specimen), degree of computerization, direction of purge gas flow (horizontal or vertical) with respect to the sample specimen, and microbalance type and sensitivity. Recent years have brought computerization of data handling as well as many of the hardware components of the technique. This paper will present and discuss the role of the basic components of a thermogravimetric apparatus in performing compositional analysis. Some of the aspects of computerization of the technique will be included.
Journal of Chemical Education, 1978
Compositional Analysis by Thermogravimetry
The application of thermogravimetry to the characterization of kaolinite and smectite clay minera... more The application of thermogravimetry to the characterization of kaolinite and smectite clay minerals is presented. Examples of differing crystallinity of kaolinites are used. In the study of the smectite clay minerals bothdioctahedral and trioctahedral members are included. A unique industrial example of the use of thermogravimetry to follow the cleaning of a bentonite specimen and then its conversion to an organo-clay product, which is used as a component of drilling fluids in the petroleum industry, is demonstrated. Several hectorite specimens representing both raw carbonate bearing clay mineral ores and processed hectorite (carbonate-cleaned) specimens were analyzed by computerized thermogravimetry.
Astm Special Technical Publication, 1988
Lecture Notes in Earth Sciences
The characterization of illite clay minerals by the use of the technique of differential thermal ... more The characterization of illite clay minerals by the use of the technique of differential thermal analysis (DTA), thermogravimetry (TG) and derivative thermogravimetry (DTG) is presented. This presentation is offered not only as a review of the thermal characteristics of this important group of clay materials but suggestions relative to the application of the thermal analysis techniques to contaminated illitic specimens; i.e., mineral mixtures, are included. Two commonly referenced illitic clay specimens, which have been widely distributed, were studied here. These were the American Petroleum Institute Reference Clay Specimen from Fithian, Illinois (API #35) and the Clay Mineral Society's Source Clay Specimen from Silver Hill, Montana (CMS-IMt).
Assignment of the Glass Transition
The use of thermomechanical analysis (TMA) as a tool for assignment of glass transition temperatu... more The use of thermomechanical analysis (TMA) as a tool for assignment of glass transition temperatures, T{sub g}, is discussed in this paper. An attempt to address the minimum requirements of TMA instrumentation necessary for T{sub g} assignments is included. The subject of temperature calibration of the TMA instrument, which is a prerequisite for any temperature of transition assignment, is discussed.
Advances in Materials Characterization, 1983
It was in 1887 when Le Chatelier,1 published heating curves of clays (including kaolinite and hal... more It was in 1887 when Le Chatelier,1 published heating curves of clays (including kaolinite and halloysite) using a photographic recording of the reflection of a galvonometer mirror which was activated by a thermocouple in the sample. Although this study was not conducted in a differential fashion, DTA originated twelve years later in 1899,2 and the study of clays and silicate minerals propagated the technique for the next 40 years. According to Wendlandt,3 with few exceptions, DTA was used exclusively for the studies of clay materials by geologists, ceramicists, soil scientists and mineralogists until the late 1940’s and early 1950’s.
Analytical Calorimetry, 1984
Recent years have seen vast experimentation with many different process designs for the liquefact... more Recent years have seen vast experimentation with many different process designs for the liquefaction of coals. The degree of coal conversion and composition of the product oil vary with both the coal rank, maceral composition, mineral matter content, and conversion process. Whereas much attention has been focused on the separation and characterization of the product oil by chromatographic and spectroscopic means, less work has been done on the unconverted or process altered residues from liquefaction processes. Although many of the processes do incorporate some sort of “bottoms processing”, other possible uses of these residues include road materials, carbon electrodes, coal gasification feedstocks, and as direct combustion fuels. Recently, coal conversion by-products have been used as raw materials in the synthesis of thermosetting polyesters1.
... of Sheet Molding Compound Materials to Determine Distribution of Compound Components in Molde... more ... of Sheet Molding Compound Materials to Determine Distribution of Compound Components in Molded Parts PAULA J. LORIGAN ... Wood to Coal: A Compositional Thermogravimetric Analysis HANS G. WIEDEMANN, RUDOLF RIESEN, ANDREAS BOLLER, AND GERHARD ...
Thermochimica Acta, 1982
The pyrolysis profile for the U.S. Geological Survey SGR-1 Green River shale specimen is reported... more The pyrolysis profile for the U.S. Geological Survey SGR-1 Green River shale specimen is reported using computerized TG and DTG techniques. The thermal behavior of this specimen in dynamic nitrogen atmosphere is compared with that of a retort composite (spent shale) specimen obtained from one of the current thermal retorting processes. The quantitative differences between these two specimens are discussed in terms of the thermal retorting of shales from the Western United States. A carefully performed comparative study of the Australian Rundle, Glen Davis, and Alpha Deposits as well as the USGS-SGR-1 Green River specimen is also given here. Using the results of this study, the pyrolysis onset temperatures and temperatures at maximum pyrolysis rate were related to the type of organic maceral components of the shale specimens. These shales were also compared for total carbon, hydrogen, and nitrogen content by elemental analysis. A drilled core specimen from Western Colorado of known oil yield versus depth of seam was used to correlate the DTG pyrolysis peak area to the Fisher assay oil yield assignments. A method of precise assignment of DTG peak areas which is often overlooked is also demonstrated.
Thermochimica Acta, 1990
Abstract The role and application of microfurnace technology in modern thermogravimetry are discu... more Abstract The role and application of microfurnace technology in modern thermogravimetry are discussed. The construction and advantages and disadvantages of such microfurnaces are presented. All the microfurnaces considered are commercial platinum-wound ceramic mandrels which have been coated with an alumina-based ceramic material by a special flame spray mechanism. Methodology for extending the lifetime of such furnaces through proper cleaning procedures is also given.
Thermochimica Acta, 1985
... 1ft 40 TEMPERATURE <0 |>^ ui^TOL. ^* Figure 1 CMT ^fiZ^B^ TEMPERATURE <0... more ... 1ft 40 TEMPERATURE <0 |>^ ui^TOL. ^* Figure 1 CMT ^fiZ^B^ TEMPERATURE <0 ^^ !^^ WVSt UWW TINEi Hi 14 Figure 2 - 364 - TENPERATORE CC) Figure 3 LOW TEMPERATURE ASH (DYNAMIC AIR ATMOSPHERE) 4 4Jl Figure 4 Figure 5. References. ...
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Papers by Charles Earnest