Improved instrument for measuring the viscosity of glass in the temperature interval of glass softening and annealing

1971 ◽  
Vol 28 (4) ◽  
pp. 234-237
Author(s):  
E. S. Sorkin ◽  
I. V. Kuzmin ◽  
M. B. Geibtman ◽  
B. S. Belostotskii ◽  
M. A. Zezin
Keyword(s):  
Temperature Interval ◽  
Glass Softening

Heat capacities of liquid 2,3,6-trimethylpyridine, 2,4,6-trimethylpyridine and 3-methoxypropionitrile within the range of temperatures of 300 to 328 K

1991 ◽  
Vol 56 (12) ◽  
pp. 2786-2790 ◽  
Author(s):  
Václav Svoboda ◽  
Milan Zábranský
Keyword(s):  
Temperature Interval ◽  
Atmospheric Pressure ◽  
Liquid State ◽  
Adiabatic Calorimeter ◽  
Heat Capacities

Molar heat capacities of 2,3,6-trimethylpyridine, 2,4,6-trimethylpyridine and 3-methoxypropionitrile in the liquid state were measured at the constant atmospheric pressure in the temperature interval of 300.60 to 328.35 K. The static type of adiabatic calorimeter was used for the measurements.

scholarly journals The formation conditions of birch tar in oxygen-depleted environments

2021 ◽  
Vol 13 (6) ◽  
Author(s):  
Tabea J. Koch ◽  
Patrick Schmidt
Keyword(s):  
Temperature Interval ◽  
Production Systems ◽  
Technical Skills ◽  
Middle Palaeolithic ◽  
Dry Distillation ◽  
Narrow Temperature Interval ◽  
Glass Tubes ◽  
Formation Conditions ◽  
The Relationship ◽  
Heating Duration

AbstractBirch tar is the oldest manmade adhesive dating back to the European Middle Palaeolithic. Its study is of importance for understanding the cognitive capacities and technical skills of Neanderthals and the aceramic production systems employed in the European Palaeolithic and Mesolithic. Several methods may have been used to make birch tar, the most common proposition being dry distillation in oxygen-depleted atmospheres. One of the major impediments for our understanding of the conditions employed to make Neanderthal birch tar, and ultimately the technique used, is that it remains unknown at which temperatures exactly birch tar forms. The relationship between heating duration and tar formation is also unknown. To address these questions, we conduct a laboratory heating experiment, using sealed glass tubes and an electric furnace. We found that birch tar is only produced at a narrow temperature interval (350 °C and 400 °C). Heating times longer than 15 min have no effect on the quantity of tar produced. These findings, notwithstanding previous propositions of necessarily long heating times and larger tolerances for temperature, have important implications for our understanding of the investment in time needed for Palaeolithic birch tar making.

scholarly journals Specific heat of refractory carbides (ZrC0.95, HfC0.85 and Ta0.8Hf0.2C) in the temperature interval 2500-5000 K

2020 ◽  
Vol 1686 ◽  
pp. 012055
Author(s):  
A I Savvatimskiy ◽  
NM Aristova ◽  
S V Onufriev ◽  
G E Valiano
Keyword(s):  
Specific Heat ◽  
Temperature Interval

An Improved Low-Temperature Brittleness Test

1949 ◽  
Vol 22 (3) ◽  
pp. 820-827 ◽  
Author(s):  
E. F. Smith ◽  
G. J. Dienes
Keyword(s):  
Low Temperature ◽  
Temperature Interval ◽  
Statistical Study ◽  
Distribution Curve ◽  
Simple Analysis ◽  
Reasonable Amount ◽  
Brittle Point

Abstract An improved low-temperature brittleness tester, capable of testing five specimens simultaneously, is described. All machine specifications conform to A.S.T.M. Method D 746-44T. Data are presented which show that many elastomers do not possess a sharp brittle point but are characterized by a distribution of failures over a temperature interval. The improved brittleness tester makes it possible to carry out the necessary statistical study of the distribution of per cent failures versus temperature with a reasonable amount of work. A simple analysis of the resulting distribution curve is presented.

Ion Transport in Alumina-Pillared Zirconium Phosphate

1992 ◽  
Vol 286 ◽  
Author(s):  
C. Criado ◽  
J.R. Ramos-Barrado ◽  
P. Maireles-Torres ◽  
P. Oliverapastor ◽  
A. Jimenez-Lopez ◽  
...  
Keyword(s):  
Ion Transport ◽  
Equivalent Circuit ◽  
Temperature Interval ◽  
Zirconium Phosphate ◽  
Lithium Ion ◽  
Charge Carriers ◽  
Impedance Method ◽  
Electrical Behaviour ◽  
Lithium Ions ◽  
Zirconium Phosphates

ABSTRACTA.c. conductivity of a novel large-pore alumina-pillared zirconium phosphate and some lithium ion exchanged samples have been measured by an impedance method. These materials have a conductivity in the range 10-5 to 10-9 Ω-1cm-1 higher than those of alumina-pillared tin phosphate and its lithium derivatives. The electrical behaviour of the pillared zirconium phosphates fits to an equivalent circuit composed by two subcircuits in parallel with a condenser. In a temperature interval (200-500°C), lithium ions are charge carriers and the conductivity increases when heating with activation energies between 0.99 and 1.22 eV.

On the Regulation of the Respiration in Reptiles

1961 ◽  
Vol 38 (2) ◽  
pp. 301-314 ◽  
Author(s):  
BODIL NIELSEN
Keyword(s):  
Steady State ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Temperature Interval ◽  
Normal Values ◽  
Pulmonary Ventilation ◽  
The Body ◽  
Respiratory Frequency ◽  
Temperature Changes ◽  
Instantaneous Increase

1. In two species of Lacerta (L. viridis and L. sicula) the effects on respiration of body temperature (changes in metabolic rate) and of CO2 added to the inspired air were studied. 2. Pulmonary ventilation increases when body temperature increases. The increase is brought about by an increase in respiratory frequency. No relationship is found between respiratory depth and temperature. 3. The rise in ventilation is provoked by the needs of metabolism and is not established for temperature regulating purposes (in the temperature interval 10°-35°C). 4. The ventilation per litre O2 consumed has a high numerical value (about 75, compared to about 20 in man). It varies with the body temperature and demonstrates that the inspired air is better utilized at the higher temperatures. 5. Pulmonary ventilation increases with increasing CO2 percentages in the inspired air between o and 3%. At further increases in the CO2 percentage (3-13.5%) it decreases again. 6. At each CO2 percentage the pulmonary ventilation reaches a steady state after some time (10-60 min.) and is then unchanged over prolonged periods (1 hr.). 7. The respiratory frequency in the steady state decreases with increasing CO2 percentages. The respiratory depth in the steady state increases with increasing CO2 percentages. This effect of CO2 breathing is not influenced by a change in body temperature from 20° to 30°C. 8. Respiration is periodically inhibited by CO2 percentages above 4%. This inhibition, causing a Cheyne-Stokes-like respiration, ceases after a certain time, proportional to the CO2 percentage (1 hr. at 8-13% CO2), and respiration becomes regular (steady state). Shift to room air breathing causes an instantaneous increase in frequency to well above the normal value followed by a gradual decrease to normal values. 9. The nature of the CO2 effect on respiratory frequency and respiratory depth is discussed, considering both chemoreceptor and humoral mechanisms.

Sign in / Sign up

Export Citation Format

Share Document