Some Measurements of Thermal Transpiration

Liang, Shuxiu

doi:10.1063/1.1699916

Cited by 63 publications

(23 citation statements)

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“…respectively. The full lines are the curves calculated from equation [5]. In the case of helium, the dotted curve represents that calculated from the Weber equation.…”

Section: Comparison With Experimentsmentioning

confidence: 99%

“…B y following the argument put forward earlier (5, pp. 150-151), equation [ l l ] is transformed into equation [5].…”

Section: Derivation Of Equation [5]mentioning

confidence: 99%

“…Equation [3] was later modified slightly (7) to take a more readily usable form by referring t o helium as the standard, and defining &, = 1. Equation [5] has been found to be applicable to a t least eight gases, namely, helium, neon, hydrogen, argon, nitrogen, krypton, xenon, and ethylene; and it is expected to be equally applicable t o others.…”

Section: Introductionmentioning

confidence: 99%

“…Equation [5] can be reduced readily to T h e practical advantage of equation [GI over the Weber equation and its variation (equations [ I ] and [3]) is immediately obvious. I t is therefore desirable to investigate whether there is any reasonable basis for its existence; and to examine whether, mathematically, it conforms t o all the known facts.…”

Section: Introductionmentioning

confidence: 99%

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On the Calculation of Thermal Transpiration

Liang¹

1955

Can. J. Chem.

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The equation proposed earlier has been derived from a new kinetic concept. I t is shown t o be a reasonable approximation of this new consideration. The equation is also shown to be mathematically consistent with the general fact that when the thermomolecular pressure difference is plotted against the normally measured pressure, a single maximum is obtained. T h e curves calculated from this equation are shown t o agree closely with those from the Weber equation using van Itterbeek and de Grande's data. T h e practical use of the equation is discussed. INTRODUCTIONThe problem of the effect of thermal transpiration on pressure, or the thermomolecular pressure difference, was observed and investigated by a number of workers both experimentally and mathematically (1,4, 9). Although a practical solution was not obtained, the problem was neglected for many years. I t was not even mentioned in most publications where it was obviously important.Recently, Weber and his co-workers reinvestigated this problem and showed the extent to which a pressure measurement may be affected (11, 12). More recently, the problem was again brought to the general attention of this continent. Its practical importance was demonstrated by Liang (6) in the the case of vapor pressure measurement, and by Crowell and Young (2) in the case of physical adsorption.Until very recently, the only available equation by which the thermal transpiration effect may be calculated was a semiempirical one obtained by Weber and his co-workers. The equation was derived along the line given by Maxwell with modifications suggested by Weber, and took the general form in which y = R/X, R being the tube radius and X the mean free path of the gas; n was related to the viscosity q by the equation B , C, D, m, m', and m" were constants calculated from another three semiempirical constants, kl, k?, and p, which in turn were evaluated from the experimental data. Weber and Schmidt (13) calculated the constants for helium. van Itterbeek and de Grande (10) found that the values of kl, k?, and p were functions of the nature of the gas and that separate determinations for different gases must be made. They extended the equation accordingly to cover the cases of hydrogen, deuterium, and neon. l d~a~z z~s c r i p t

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“…respectively. The full lines are the curves calculated from equation [5]. In the case of helium, the dotted curve represents that calculated from the Weber equation.…”

Section: Comparison With Experimentsmentioning

confidence: 99%

“…B y following the argument put forward earlier (5, pp. 150-151), equation [ l l ] is transformed into equation [5].…”

Section: Derivation Of Equation [5]mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Calculation of Thermal Transpiration

Liang¹

1955

Can. J. Chem.

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“…A careful review of the available literature was made [9,10,11,12], and the following equation of Liang [11] was considered the most appropriate for calculating the thermal transpiration factors:…”

Section: Corrections For Thermomolecular Diffusionmentioning

confidence: 99%

Adsorption of nitrogen on carbon adsorbents at low pressures between 69 and 90 K

López-González¹,

Carpenter²,

Deitz³

1955

J. RES. NATL. BUR. STAN.

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X i t r ogen ad so rp ti on i,otherm s \\'er e dete rmin ed o n t hree car bo n ad so r ben t s (tw o bon e cha r s and an ac t i vated coco n u t shell ch ar coal) a t t hree te m per atu r es bet w ee n 69° and 90° K and at r el at i ve pre:is urcs from 10-7 t o 0.9. A cr. vost a t was uscd t o ob tain tc m perat u res below t he norm al bo iling point of l i q uid ni t r ogen . Th e a t tainmen t o f steady pressure r eadi ngs a t v cr y low p ressu r es r equired consid er ab l y m o r e t im e t han a t h ig her pr essu r es.Con ect io ns for t her m om olec ul ar diffu sio n \\'ere foun d to b e ap p rec iab l e at p r essures b el o\\' one m illim eter o f mer cury .A t r elati ve p r ess ures b elo w 10-' , t he amo un t o f ni t r ogen ad so rb ed d epended upon t he co nd i t io n o f t he surf ace in reg ar d t o p r ev iou s ad so r ptio n of ni troge n. A tec h ni q ue i n vo l v i ng a seri es of co nsec u t i \' e ad so r p t ion s at lo w te mper atures and o u t~ass i n g s a t r oo m te mperat ur e led to a rep rod ucib le iso t herm a t low p ressures. T hese d ata co u ld b e r ep resen ted b y a F r c u ncl li ch equ atio n. Th e Bruna uer , Emmett, T ell er su r f ace ar eas of t he ca rbo n a cl so rbc nt s wer e also dct'e r min ecl .

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Total Pressure Vacuum Gauges

Jousten

2016

Handbook of Vacuum Technology

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Some Measurements of Thermal Transpiration

Cited by 63 publications

References 2 publications

On the Calculation of Thermal Transpiration

On the Calculation of Thermal Transpiration

Adsorption of nitrogen on carbon adsorbents at low pressures between 69 and 90 K

Total Pressure Vacuum Gauges

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