scholarly journals The combustion of aromatic and alicyclic hydrocarbons. II. The ignition of aromatic hydrocarbons at high temperatures

1939 ◽  
Vol 171 (946) ◽  
pp. 421-433 ◽  
Keyword(s):  
High Temperatures ◽  
Aromatic Hydrocarbons ◽  
Isothermal Oxidation ◽  
Present Communication ◽  
Temperature Range ◽  
Benzene Toluene ◽  
The Subject ◽  
Kinetics Of

In the first paper of this series (Burgoyne 1937) the kinetics of the isothermal oxidation above 400° C of several aromatic hydrocarbons was studied. The present communication extends this work to include the phenomena of ignition in the same temperature range, whilst the corresponding reactions below 400° C form the subject of further investigations now in progress. The hydrocarbons at present under consideration are benzene, toluene, ethylbenzene, n -propylbenzene, o-, m - and p -xylenes and mesitylene.

scholarly journals XIX.—Magnetization and Resistance of Nickel Wire at High Temperatures. Part II.

1907 ◽  
Vol 45 (3) ◽  
pp. 547-554
Author(s):  
C. G. Knott
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Electrical Resistance ◽  
British Association ◽  
Nickel Wire ◽  
Present Communication ◽  
Association Meeting ◽  
The Subject ◽  
The Wire

The experiments which form the subject of the present communication were carried out two years ago, and supplement results already published. A brief note of some of the results was read before the Society in June 1904, and was also read before the British Association Meeting at Cambridge in August of the same year.The previous paper discussed the effect of high temperature on the relation between electrical resistance and magnetization when the wire was magnetized longitudinally, that is, in the direction in which the resistance was measured.The present results have to do with the effect of high temperature on the relation between resistance and magnetization when the magnetization was transverse to the direction along which the resistance was measured.

scholarly journals Temperature Dependent Seed Germination of Dalbergia nigra Allem (Leguminosae)

2001 ◽  
Vol 44 (4) ◽  
pp. 401-404 ◽  
Author(s):  
Fernanda G. A. Ferraz-Grande ◽  
Massanori Takaki
Keyword(s):  
Seed Germination ◽  
Endangered Species ◽  
High Temperatures ◽  
Broad Temperature Range ◽  
Optimum Temperature ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dalbergia Nigra ◽  
The Mean ◽  
Kinetics Of

The germination of endangered species Dalbergia nigra was studied and 30.5° C was found as optimum temperature, although the species presented a broad temperature range where germination occurs and light had no effect. The analysis of kinetics of seed germination confirmed the asynchronized germination below and above the optimum temperature. The light insensitive seed and germination also at high temperatures indicated that D. nigra could occur both in understories and gaps where the mean temperature was high.

scholarly journals The effect of thermal agitaion on atomic arrangement in alloys—II

1935 ◽  
Vol 151 (874) ◽  
pp. 540-566 ◽  
Keyword(s):  
High Temperatures ◽  
Experimental Work ◽  
Low Temperatures ◽  
Theoretical Treatment ◽  
X Ray ◽  
Atomic Arrangement ◽  
Metal Atoms ◽  
Theoretical Investigations ◽  
The Subject ◽  
Kinetics Of

The transformations between a disordered arrangement of the metal atoms in an alloy at high temperatures and an ordered arrangement of the atoms at low temperatures have formed the subject of many experimental and theoretical investigations. The process of segregation into regular positions was first envisaged by Tammann in 1919. It was proved to take place in the gold-copper and other alloy systems by Johannson and Linde by X-ray investigation. Theoretical treatments of the problem have been given in papers by Borelius, Johannson, and Linde, Gorsky, and Dehlinger and Graf, and the same authors have published a large amount of experimental work on this type of transformation in the Au-Cu system. Some experiments on order-disorder transformations in the Fe-Al system, carried out by Bradley and Jay in this laboratory, led us to examine the kinetics of the change, and we recently published a paper in these Proceedings dealing with various aspects of it. Since publishing this paper, we have become aware that our theoretical treatment has in several respects a closer parallelism to those of Borelius, Gorsky, and Dehlinger than we realized at the time of writing it. We shall try to make a proper acknowledgment in the present paper.

The Nature of Structural Changes of Butadiene Rubbers Caused by High Temperatures (100–200° C)

1952 ◽  
Vol 25 (1) ◽  
pp. 33-35 ◽  
Author(s):  
A. S. Kuzminskii˘ ◽  
I. A. Shokhin ◽  
R. M. Belitzkaya
Keyword(s):  
Tensile Strength ◽  
Thermal Effect ◽  
High Temperatures ◽  
Structural Changes ◽  
Temperature Range ◽  
The Subject ◽  
Mechanism Of Oxidation

Abstract In theories developed by Kuzminskii˘ and his collaborators concerning the mechanism of oxidation of rubbers, the question of a direct thermal effect on their structure was not discussed. Nevertheless, with certain rubbers, structural changes which are caused by high temperatures play a very important part in the total complex of structural changes undergone by these rubbers during processing and, after vulcanization, by their products during service. Dogadkin, Zayonchkovskii˘, Zayonchkovskaya, Pisarenko, and Astafyez, Kuzminskii˘, Shanin, Degteva, Lapteva, and other Soviet investigators have shown that, when butadiene rubbers are heated in the temperature range of 100–200° C, structural changes take place which are characterized by increases of tensile strength and modulus, decrease of extensibility, decrease of unsaturation, etc. The question of the causes of such extensive changes in rubber is the subject of this discussion. Rebinder has proven unsubstantiated the reasoning of several investigators regarding these processes, and has shown the necessity of carrying out direct experiments which would provide an explanation of their nature.

Barite Nucleation and Inhibition at 0 to 200°C With and Without Thermodynamic Hydrate Inhibitors

SPE Journal ◽  
2010 ◽  
Vol 16 (02) ◽  
pp. 440-450 ◽  
Author(s):  
Chunfang Fan ◽  
Amy T. Kan ◽  
Ping Zhang ◽  
Mason B. Tomson
Keyword(s):  
High Temperatures ◽  
Inhibition Efficiency ◽  
Saturation Index ◽  
Pressure Change ◽  
Accurate Method ◽  
Nucleation Kinetics ◽  
Temperature Range ◽  
Mineral Scale ◽  
Relationship Of ◽  
Kinetics Of

Summary In this study, we modified the commonly employed dynamic-tube-blocking methodology and built an apparatus to study the nucleation kinetics of barite-scale formation at high temperatures in the presence and absence of scale inhibitors. Barite formation was detected by monitoring pressure change over a micrometer-sized in-line filter, and this has been proved to be an easy and accurate method to study mineral-scale-nucleation kinetics at high temperatures. Additionally, we investigated the nucleation kinetics of barite at 0–25°C with and without thermodynamic hydrate inhibitors. By using this modified dynamic-tube-blocking technique, we successfully measured the nucleation kinetics of barite in 1M NaCl solutions over a temperature range from 25 to 200°C and at various supersaturation conditions. We also evaluated the inhibition efficiency of barite precipitation at this high temperature range. On the basis of the experimental results, the relationship of precipitation kinetics of barite as a function of temperature and saturation index was established. The inhibition efficiency of the phosphonate inhibitor [bis-hexamethylenetriamine-penta (methylene phosphonic) acid (BHPMP)] on barite precipitation has been evaluated over the same range of conditions. The Ca2+ effect on the inhibition efficiency of BHPMP at a low temperature (4°C) and at high temperatures (175–200°C) was investigated also. Results of this study have been incorporated into the scale-prediction software ScaleSoftPitzer.

scholarly journals The combustion of aromatic and alicyclic hydrocarbons. IV. The kinetics of the slow combustion of benzene and its mono-alkyl derivatives at low temperatures

1940 ◽  
Vol 174 (958) ◽  
pp. 394-409 ◽  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Low Temperatures ◽  
Side Chain ◽  
Oxidation Reactions ◽  
Alkyl Derivatives ◽  
Single Side ◽  
Slow Combustion ◽  
Benzene Toluene ◽  
Kinetics Of

In previous papers of this series the ignition and slow-combustion reactions of a number of aromatic hydrocarbons have been examined, mainly from the kinetic standpoint. In the present and following communications it is proposed further to consider benzene and its single side-chain derivatives, in relation particularly to the oxidation reactions occurring below 400° C, and to correlate this mode of combustion by kinetic and analytical observations with the types previously examined. The hydrocarbons to which attention is chiefly directed are benzene, toluene, ethylbenzene, n -propylbenzene and n -butylbenzene.

Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

2017 ◽  
Vol 68 (1) ◽  
pp. 116-120
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
Lucian Mihail Birsa ◽  
Ioan Gabriel Sandu ◽  
Laura Gabriela Sarbu ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Metal Content ◽  
Pulse Method ◽  
Acid Strength ◽  
Strength Distribution ◽  
Zeolite Catalysts ◽  
Benzene Toluene ◽  
Acid Strength Distribution ◽  
Silver Cations ◽  
Heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

Effects of Nb doping on thermoelectric properties of Zn4Sb3 at high temperatures

2009 ◽  
Vol 24 (2) ◽  
pp. 430-435 ◽  
Author(s):  
D. Li ◽  
H.H. Hng ◽  
J. Ma ◽  
X.Y. Qin
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperatures ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Temperature Range ◽  
A Value ◽  
Nb Doping ◽  
Thermal Conductivities

The thermoelectric properties of Nb-doped Zn4Sb3 compounds, (Zn1–xNbx)4Sb3 (x = 0, 0.005, and 0.01), were investigated at temperatures ranging from 300 to 685 K. The results showed that by substituting Zn with Nb, the thermal conductivities of all the Nb-doped compounds were lower than that of the pristine β-Zn4Sb3. Among the compounds studied, the lightly substituted (Zn0.995Nb0.005)4Sb3 compound exhibited the best thermoelectric performance due to the improvement in both its electrical resistivity and thermal conductivity. Its figure of merit, ZT, was greater than the undoped Zn4Sb3 compound for the temperature range investigated. In particular, the ZT of (Zn0.995Nb0.005)4Sb3 reached a value of 1.1 at 680 K, which was 69% greater than that of the undoped Zn4Sb3 obtained in this study.

ON MEASUREMENT OF THERMAL CONDUCTIVITY AT HIGH TEMPERATURES

1961 ◽  
Vol 39 (7) ◽  
pp. 1029-1039 ◽  
Author(s):  
M. J. Laubitz
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
High Temperatures ◽  
Mathematical Analysis ◽  
Temperature Range ◽  
Linear Heat ◽  
Flow Systems

A method is given for exact mathematical analysis of linear heat flow systems used in measuring thermal conductivity at high temperatures. It is shown that a popular version of such a system is very sensitive to the alignment of its components, which seriously limits the temperature range of its satisfactory use.

Oxidation kinetics of polycyclic aromatic hydrocarbons by permanganate

Chemosphere ◽  
2010 ◽  
Vol 79 (6) ◽  
pp. 628-636 ◽  
Author(s):  
Steven P. Forsey ◽  
Neil R. Thomson ◽  
James F. Barker
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Oxidation Kinetics ◽  
Polycyclic Aromatic ◽  
Kinetics Of
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