α- and β-Monopalmitin, Heats of Combustion and Specific Heats at 25°1

1940 ◽  
Vol 62 (7) ◽  
pp. 1815-1817 ◽  
Author(s):  
Theodore H. Clarke ◽  
Gebhard Stegeman
Keyword(s):  
Specific Heats ◽  
Heats Of Combustion

scholarly journals Boilers slagging when burning wood pellets

2022 ◽  
Vol 1211 (1) ◽  
pp. 012006
Author(s):  
V K Lyubov ◽  
A V Malkov ◽  
P D Alekseev
Keyword(s):  
Environmental Performance ◽  
Hot Water ◽  
Transportation Costs ◽  
Wood Pellets ◽  
Promising Trend ◽  
Specific Heats ◽  
Nominal Capacity ◽  
Heats Of Combustion ◽  
Main Factors ◽  
Negative Phenomena

Abstract A promising trend for upgrading wastes from timber cutting, processing and treatment is their granulation. It allows to increase their specific heats of combustion by 2.5– 3.5 times and their portability characteristics by 3–4 times, to reduce transportation costs by 6– 10 times and to improve all the operations stages. The construction and commissioning of boiler facilities operating on refined biofuel made it possible to form a stable domestic market for wood pellets. However, 0.5 – 1.5 MW nominal capacity hot water boilers equipped with furnaces and profiled burners at the bottom, in cold seasons had fast accumulation of focal residues deposits in the burners and on the furnace chambers lining. The process was complicated by these deposits hardening due to their melting and sintering. These circumstances cause a decrease in the energy and environmental performance of heat-generating installations and their reliability, and also leads to the unplanned shutdowns to clean the boiler furnaces. To find out the reasons for these negative phenomena and to develop recommendations for their elimination, a set of research operations was carried out with wood pellets shipped by the manufacturer and supplied to the burners of the boilers under the analyses; with focal residues accumulated in the burners and on the lining of the furnace chambers; as well as an analysis of the heat generating facilities operation modes. The studies carried out made it possible to identify the main factors that caused these negative phenomena and to develop the recommendations for their elimination.

Heats of Combustion and Specific Heats of Buna-S Treated in Various Ways

1942 ◽  
Vol 15 (4) ◽  
pp. 874-878 ◽  
Author(s):  
W. A. Roth ◽  
Gerhilde Wirths ◽  
Hildegarde Berendt
Keyword(s):  
Specific Heats ◽  
Thermal Data ◽  
Heats Of Combustion

Abstract Measurements of the heats of combustion and specific heats (between 20° and 50° C) of crude untreated Buna-S, highly degraded Buna-S, and cyclized Buna-S are reported. The heats of combustion are then discussed. A well defined relation exists between thermal data and changes which take place in Buna-S. In the case of specific heats, the values of which are less precise, the relation is not so clearly defined.

Constructing Quantum Mechanics

2019 ◽  
Author(s):  
Anthony Duncan ◽  
Michel Janssen
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Stark Effect ◽  
Zeeman Effect ◽  
Black Body ◽  
Black Body Radiation ◽  
Wave Mechanics ◽  
Specific Heats ◽  
Old Quantum Theory ◽  
Upper Level

This is the first of two volumes on the genesis of quantum mechanics. It covers the key developments in the period 1900–1923 that provided the scaffold on which the arch of modern quantum mechanics was built in the period 1923–1927 (covered in the second volume). After tracing the early contributions by Planck, Einstein, and Bohr to the theories of black‐body radiation, specific heats, and spectroscopy, all showing the need for drastic changes to the physics of their day, the book tackles the efforts by Sommerfeld and others to provide a new theory, now known as the old quantum theory. After some striking initial successes (explaining the fine structure of hydrogen, X‐ray spectra, and the Stark effect), the old quantum theory ran into serious difficulties (failing to provide consistent models for helium and the Zeeman effect) and eventually gave way to matrix and wave mechanics. Constructing Quantum Mechanics is based on the best and latest scholarship in the field, to which the authors have made significant contributions themselves. It breaks new ground, especially in its treatment of the work of Sommerfeld and his associates, but also offers new perspectives on classic papers by Planck, Einstein, and Bohr. Throughout the book, the authors provide detailed reconstructions (at the level of an upper‐level undergraduate physics course) of the cental arguments and derivations of the physicists involved. All in all, Constructing Quantum Mechanics promises to take the place of older books as the standard source on the genesis of quantum mechanics.

scholarly journals On the measurement of the ratio of the specific heats using small volumes of gas.—The ratios of the specific heat of air and of hydrogen at atmospheric pressure and a temperatures between 20°C. and —183°C

1925 ◽  
Vol 107 (743) ◽  
pp. 510-543 ◽  
Keyword(s):  
Systematic Error ◽  
Low Temperatures ◽  
Room Temperature ◽  
Expansion Chamber ◽  
Small Vessels ◽  
Specific Heats ◽  
Large Expansion ◽  
Before And After ◽  
The One ◽  
Chamber Capacity

Introduction .—In nearly all the previous determinations of the ratio of the specific heats of gases, from measurements of the pressures and temperature before and after an adiabatic expansion, large expansion chambers of fror 50 to 130 litres capacity have been used. Professor Callendar first suggests the use of smaller vessels, and in 1914, Mercer (‘Proc. Phys. Soc.,’ vol. 26 p. 155) made some measurements with several gases, but at room temperature only, using volumes of about 300 and 2000 c. c. respectively. He obtained values which indicated that small vessels could be used, and that, with proper corrections, a considerable degree of accuracy might be obtained. The one other experimenter who has used a small expansion chamber, capacity about 1 litre, is M. C. Shields (‘Phys. Rev.,’ 1917), who measured this ratio for air and for hydrogen at room temperature, about 18° C., and its value for hydroger at — 190° C. The chief advantage gained by the use of large expansion chambers is that no correction, or at the most, a very small one, has to be made for any systematic error due to the size of the containing vessels, but it is clear that, in the determinations of the ratio of the specific heats of gases at low temperatures, the use of small vessels becomes a practical necessity in order that uniform and steady temperature conditions may be obtained. Owing, however, to the presence of a systematic error depending upon the dimensions of the expansion chamber, the magnitude of which had not been definitely settled by experiment, the following work was undertaken with the object of investigating the method more fully, especially with regard to it? applicability to the determination of this ratio at low temperatures.

scholarly journals The energy equivalents of ATP and the energy values of food proteins and fats

1984 ◽  
Vol 51 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Geoffrey Livesey
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Oxidative Phosphorylation ◽  
G Protein ◽  
Compositional Data ◽  
Metabolizable Energy ◽  
Food Proteins ◽  
Protein Nitrogen ◽  
Food Composition Tables ◽  
Heats Of Combustion

1. Heats of combustion and energy equivalents of cytoplasmic ATP have been estimated for glucose, 101 food proteins and 116 food fats based on amino acid and fatty acid composition data from food composition tables and the heats of combustion and energy equivalents of cytoplasmic ATP of each individual amino acid, fatty acid, glycerol and glucose. The isodynamic equivalents of carbohydrate, fat and protein at the biochemical level have been investigated.2. Heats of combustion of food proteins and fats derived from compositional data were within 1 % of published values obtained by calorimetry.3. Cytoplasmic ATP equivalents for glucose, fat and protein range from 9·0 to 14·7, 8·6 to 14·6 and 6·4 to 13·2 mol cytoplasmic ATP/MJ of metabolizable energy respectively, depending on the choice of mitochondrial proton stoichiometries for these estimations. The range is extended further when considering the level and type of mitochondrial ‘uncoupling’.4. Isobioenergetic relationships between the efficiencies of glucose (G) and fat (F) (F = 1·05 G-0·9) and glucose and protein (P) (P = G(1·02–0·19f)-(1.8+0·5f)) energy conversions (wheref is the fraction of protein oxidized via gluconeogenesis) were obtained and were essentially independent of the choice of mitochondrial proton stoichiometry and the level and type of uncoupling of oxidative phosphorylation.5. Potential errors in previous estimates of ATP yield from protein are shown to be as much as -17·6 to < 118%; accounting for the efficiency of mitochondrial oxidative phosphorylation narrows this to between -7·9 and 17·4% and accounting for the fraction of protein oxidized via gluconeogenesis limits this further to between - 7·9 and 11·1%. Remaining uncertainty is attributed mostly to lack of knowledge about the energy cost of substrate absorption from the gut and transport across cell membranes.6. Coefficients of variation (cv) in the cytoplasmic ATP yield/g protein and /g protein nitrogen for the 101 food proteins were large (0·033 and 0·058 respectively). This is attributed mostly to variation in the metabolizable heats of combustion (cv 0·033 and 0·053 respectively) and to a much smaller extent in the efficiency with which cytoplasmic ATP equivalents are generated/MJ of metabolizable energy (cv 0·01).7. It is concluded that the current understanding of biochemical energy transduction is sufficient to permit only a crude estimate of the energy equivalents of cytoplasmic ATP but that these equivalents vary by less than 5% between both different food proteins and different food fats. Isobioenergetic equivalents for carbohydrates, fats and protein which could be applied to modify the Atwater conversion factors are possible but require first an accurate quantification of the energy equivalent of cytoplasmic ATP for glucose in vivo, and an indication that oxidative phosphorylation is similarly efficient in different individuals.

Effect of supplementary firing on the performance of an integrated gasification combined cycle power plant

2000 ◽  
Vol 214 (1) ◽  
pp. 53-60 ◽  
Author(s):  
S De ◽  
P K Nag
Keyword(s):  
Power Plant ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Exergy Loss ◽  
Temperature Ratio ◽  
Integrated Gasification Combined Cycle ◽  
Specific Heats ◽  
Second Law Analysis ◽  
Integrated Gasification ◽  
Igcc Power Plant

The effect of supplementary firing on the performance of an integrated gasification combined cycle (IGCC) power plant is studied. The results are presented with respect to a simple ‘unfired’ IGCC power plant with single pressure power generation for both the gas and the steam cycles as reference. The gases are assumed as real with variable specific heats. It is found that the most favourable benefit of supplementary firing can be obtained for a low temperature ratio R T only. For higher R T, only a gain in work output is possible with a reverse effect on the overall efficiency of the plant. The second law analysis reveals that the exergy loss in the heat-recovery steam generator is most significant as the amount of supplementary firing increases. It is also noteworthy that, although the total exergy loss of the plant decreases with higher supplementary firing for a low R T (= 3.0), the reverse is the case for a higher R T (= 6.0).

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