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This section contains all refereed journal publications that have some connection either with the Mace Head Research Station or with members, both present and past, of the Atmospheric Physics Research Cluster at NUI, Galway.

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Documents

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The production of Condensation Nuclei By Heated Wires The production of Condensation Nuclei By Heated Wires

Date added: 08/07/1966
Date modified: 07/23/2009
Filesize: 4.73 MB
T.C. O'connor, AF Roddy, The production of Condensation Nuclei By Heated Wires, Journal de Recherches Atmospheriques Vol II 2e nos 2-3 pp 239-44
Abstract

 

Investigations of the condensation nuclei produced by heated wires, particularly platinum, are described. There is a 'transient' type due to surface containation and a 'permanent' type which contain the material of the wire and are about 4 x 10-7 cm in diameter. Nitrogen dioxide is also produced by the wires in the gaseous and not in the particulate form.

Condensation Nuclei In maritime Air Condensation Nuclei In maritime Air

Date added: 08/07/1966
Date modified: 07/27/2009
Filesize: 858.97 kB
O'Connor, Condensation Nuclei in Maritime Air, Journal de Recherches Atmospheriques, Vol II, 2 annee (1966), no 2-3, pp 181-184
Abstract

 

Data is reported on the concentration of condensation nuclei, their size and the fraction uncharged, in maritime air at a station on the west coast of Ireland well away from sources of man-made pollution. These are correlated with some meteorological paratmeters and the state of the ocean. These observations were made mainly with on-shore winds and they supplement those of O'Connor, Sharkey and Flanagan, in Q.J..R.M.S., 87,1961,pp. 105-8.

The concentration of nuclei per cm3 varied from about 100 to 12,500 but was usually less than 1,000. The size of the nuclei decreased with increasing concentration with an average value of about 3.5 X 10^-6 cm for their radii. It did not depend markedly on the relative humidity.

Production Of Cn by Gaseous Reactions Production Of Cn by Gaseous Reactions

Date added: 08/07/1963
Date modified: 07/23/2009
Filesize: 4.02 MB
Tom OConnor ,Production Of Cn by Gaseous Reactions, Journal de Recherches Atmospherique, pg 127 - 133 (1963)
Abstract

 

The production of condensation Nuclei as a result of gaseous reactions is discussed.  A Portable nucleus counter used to investigate sources of nuclei in the littoral zone is described. Laboratory experiments show that decaying seaweed emits a gas which forms condensation nuclei on irradiation with ultra violet or sunlight. It also emits H2S and the significance of this in the natural cycle of sulphur in the atmosphere is considered. Electrically heated wires produce very small condensation nuclei and also NO2.

On the production of Aitken nuclei by sunlight in st. Moritz  On the production of Aitken nuclei by sunlight in st. Moritz

Date added: 08/07/1962
Date modified: 07/15/2009
Filesize: 4.41 MB
C. Mc Greevy & TC O Connor, On the production of Aitken nuclei by sunlight in st. Moritz, (1962) Geofisica E Meteorologia

Abstract

 

It has been found by VERZAR & al. that the concentration of Aitken nuclei in atmospheric air increased from sunrise until  mid-day and decreased again in the afternoon. This effect occurred over the ordinary ground, in a city and also over snow. A similar effect had been reported by MCLAUGHLIN in Paris in 1926 '). It seemed likely that irradiation by the sun caused the increase in the numher of condensation nuclei. In order to study this ii suneffect ), V E R ~&~ RKU NZa nd VERZAR& EVANS  investigated nucleus-free atmospheric air stored in a polyethylene balloon and showed that the same effict took place when the air in the balloon was exposed to direct and scattered sunlight ("5). As a result of their researches and from the findings of other investigators (C.'.'") it was considered a reasonable hypothesis that trace gases in the air were partly responsible for nucleus prduction when irradiation by the sun took place. It was suggested that the production of nuclei by sunrays was due to a photochemical reaction of some impurity in the air. Suspected impurities were SO,, H,S, NH, and ozone. The amount of these contaminants in ordinary atmospheric air has
been discussed by JUNGE( 9.In support of the above hypothesis it was found that when traces of SO, or H,S or NH, were added to nucleus-free atmospheric air in such polyethylene hallons a striking increase in the number of nuclei
produced by sun irradiation occurred over the nnmher produced by irradiation when no traces were added (9. The sun-effect also took place when industrial oxygen or nitrogen replaced the nucleus-free air in the balloons. This also could he due to impurities present in the oxygen or nitrogen. In order to show quite definitely that traces of impurity
gases were partly the cause of nucleus-production in atmospheric air we decided to eliminate the suspected trace gases by filling the balloons with atmospheric air through chemicals which would absorb these trace gases or at least reduce their concentration. In this way it was hoped to he able to discover what trace gases were partly responsible for nucleus production in the sun-effect.


Mesure de l'evaporation et de la radiation globale a St. Mortiz Mesure de l'evaporation et de la radiation globale a St. Mortiz

Date added: 08/07/1962
Date modified: 07/23/2009
Filesize: 1.21 MB
T.C O Connor ,Mesure de l'evaporation et de la radiation globale a St. Mortiz , Geofisica e Meteorologia Vol X  1962

Abstract


Observations on the Aitken nuclei in Atlantic air Observations on the Aitken nuclei in Atlantic air

Date added: 01/01/1961
Date modified: 07/23/2009
Filesize: 796.79 kB

O'Connor, T.C, Sharkey, W.P.F., and Flanagan, V.P. (1961)- Observations on the Aitken nuclei in Atlantic air, Quart. J. R. Met. Soc., 87, pp.105-108.


Abstract

 

The concentration, size and distribution of charges on Aitken nuclei in air from the Atlantic Ocean were measured at a station on the western coast of Ireland where man-made pollution was most unlikely. The results are examined in relation to the meteorological elements and human activities. Some sources of the nuclei observed in maritime air are discussed.

Ionization equilibrium in aerosols Ionization equilibrium in aerosols

Date added: 01/01/1961
Date modified: 07/24/2009
Filesize: 3.34 MB
O'Connor, T.C. , Flanagan, V.P., Ionization equilibrium in aerosols, Geofisica Pura E Applicata - Milano, Vol. 50 (1961), pp. 148-154.

Abstract


Theoretical and experimental investigations were made on the time taken to achieve equilibrium charge distribution on Aitken nuclei. Theory indicates that the fraction of nuclei uncharged approaches its equilibrium value exponentially, with an approximate half time value of 0.693Z/4q and experiment gave good agreement with theory. The efficiency of a polonium-210 alpha ray source in producing ionization equilibrium in aerosols was examined and confirmed. The application of the methods described to the determination of the size of nuclei and to other observations in the free atmosphere are discussed.

Ionization Equibrium of maritime Air Ionization Equibrium of maritime Air

Date added: 08/07/1960
Date modified: 07/24/2009
Filesize: 5.83 MB
O'Connor, T.C, Sharkey, W.P, Ionization Equilibrium In Maritime Air, Procedding of the Royal irish Academy, Volume 61, Section A, No. 3
Abstract

On condensation nuclei produced at heated surfaces On condensation nuclei produced at heated surfaces

Date added: 08/31/1959
Date modified: 07/03/2009
Filesize: 1.59 MB

O'Connor, T.C, Sharkey, W.P.F., and O Brolchain, C. (1959)- On condensation nuclei produced at heated surfaces, Geofisia pura e applicata, 42, 109-116.


Abstract

 

An investigation of heated surfaces of glass, metal and oil as sources of condensation nuclei is reported. Below a certain transition temperature the nucleus production is of a temporary nature and decreases to zero with the continued heating of the surface. Above this temperature, however, the nucleus production does not change with time. The transition temperature varies with the material of the surface and is not always associated with the onset of incandescence. The nuclei produced at the lower temperatures have a radius of about 10–5 cm and, on production, are mainly uncharged. Electric light bulbs can produce appreciable numbers of these nuclei.

Further Measurements Of Global Radiation Using Black And White Atmometers Further Measurements Of Global Radiation Using Black And White Atmometers

Date added: 08/07/1957
Date modified: 07/01/2009
Filesize: 522.76 kB
TC O Connor, Further Measurements Of Global Radiation Using Black And White Atmometers, Geofisica Pura E Apllicata- Milano Vol 38 pp 154-157 (1957)

Abstract

 

The feasibility of using the difference in the evaporation from a black and whiteatmometer for the continuous routine measurement of global radiation at a field station was examined. The atmometers were operated continously for 177 days and the results obtained were compared with measurements of the global radiation for the corresponding period as given by a Bellani pyranometer. Good agreement between the monthly totals of global radiation from both methods were obtained

The Photoelectric Nucleus Counter as Hygrometer The Photoelectric Nucleus Counter as Hygrometer

Date added: 08/07/1955
Date modified: 07/22/2009
Filesize: 895.22 kB
PJ Nolan & TC O Connor, The Photoelectric Nucleus Counter as Hygrometer, Geofisica Pura E Applicata - Milano Vol. 31 pp 32-36 (1955)

Abstract

 

Hygrometric measurements on room air were made with a Nolan-Pollak nucleus counter from which the lining of blotting paper had been removed. The dew point can be determined from the critical overpressure for condensation on nuclei. Satisfactory agreement with the values given by a ventilated wet and dry blub hygrometer was obtained. The correction required is small since condensation occurs on ordinary atmospheric nuclei when the temperature is brought to about 0.3C below the dew point.

Some Characteristics of condensation Nuclei stored in a large vessel Some Characteristics of condensation Nuclei stored in a large vessel

Date added: 08/07/1955
Date modified: 07/07/2009
Filesize: 1.44 MB
TC OConnor, Some Characteristics of condensation Nuclei stored in a large vessel ,Geofisica Pura E Apllicata- Milano Vol 31 pp 107-114 (1955)

Abstract

 

THe Coagulation coefficent, size and charge distribution of condensation nuclei from room air when stored in a 4000 litre rubber balloon gasometer were studied. The results indicate that the acquisation of water vapour contributes to the growth of stored nuclei. A preliminary trial was made to see if Junge's Approximate rule that the number of particles in an aerosol varies inversely as the third power of their radius, also holds for Aitken nuclei. Further cnfirmation of the relationship between the percentage of stored nuclei electrically charged and their average radius were obtained.

The measurements were carried out by means of the Pollak-Murphy improved version of the photo-electric nucleus counter. A statistical analysis based on over a thousand comparisions of two identical models shows that the agreement of individual readings is better than 10% of nucleus concentrations in 80% of all cases. Excessive differences have now been eliminated.

Size Mobility Charge of multi charged Ions Size Mobility Charge of multi charged Ions

Date added: 08/07/1955
Date modified: 07/23/2009
Filesize: 4.14 MB
PJ Nolan and TC O'Connor ,Size Mobility Charge of multi charged Ions,  14 Dec 1955
Abstract

 

The experiments of J.J Nolan and J.G O'Keefe (1933) on multiply charged ions produced in various ways indicated that the mobility of these ions was independent of the charge. they suggusted the following way out of the difficulty: "It is possible that a nucleus on receiving a large electric charge, may in a moist atmosphere rapidly grow and adapt its size to its charge in such a way as to have approximately a constant mobility". the present research was designed to elucidate the problem by measureing the size as well as the mobility and charge of multiply charged ions. One of the methods of producing multiply charged ions used by Nolan and O'Keefe was the spraying of water. We found that production by bubblling was more convenient than production by spraying. During the course of the work certain features of the ionisation produced by bubbling were investigated. These investigations were not exhaustive since they were only incidental to the main purpose of the research.

Measurements Of Global Radiation Using Black And White Atmometers Measurements Of Global Radiation Using Black And White Atmometers

Date added: 08/07/1955
Date modified: 07/03/2009
Filesize: 1.43 MB
TC O Connor ,Measurements Of Global Radiation Using Black And White Atmometers , Geofiscica Pura E Applicata -Milano Vol 30 p 130-136 (1955)

Abstract

 

The difference in the evaporation from black and white Livingston atmometers was compared with the global radiation as measured by a Bellani spherical pyranometer. Results show that one unit (cm^3) of difference in the evaporation corresponds to 20+/- 3 cal/cm^2 of global radiation. The total of 95 daily values of radiation measured by pairs of atmometers differed from the corresponding Bellani figure by 2.3%. The operation of the atmometers and the accuracy of the results are discussed. The method is considered sufficiently accurate for the general climatological purposes.

A Photoelectric Condensation Nucleus Counter On High Precision A Photoelectric Condensation Nucleus Counter On High Precision

Date added: 08/07/1955
Date modified: 07/13/2009
Filesize: 4.73 MB
L.w Pollak & Tc O'Connor, A Photoelectric Condensation Nucleus Counter On High Precision, Geofisica Pura E Applicata Milano Vol. 32 pp 139-146

Abstract

 

A new model of the direct beam photo-electrix condensation nucleus counter and itsproperties are described. the main feature of the construction is the reduction of the fog tube diameter which resulted in the elimination of all uncertainties in the measurement of the light intensity after the fog is formed by adiabatic expansion.- Individual measurements with two identical of this design which incorporate all previous improvements, agree to better than 5% in 70% in all cases, their aver absolute difference being 2%. Deviations of more than one division of meter reading (or 10% of concentration) were not observed, This agreement is maintained over long periods. - A calibration curve of the latest model of the photo-electric nucleus counter is given

Proceedings of the Royal Irish Academy The Calibration of a photo-electric nucleus counter. Proceedings of the Royal Irish Academy The Calibration of a photo-electric nucleus counter.

Date added: 08/31/1946
Date modified: 07/22/2009
Filesize: 4.32 MB
P.J Nolan, L.W. Pollack, Proceedings of the Royal Irish Academy The Calibration of a photo-electric nucleus counter., Volume L1, Section A, No. 2, 1946

Abstract

 

Models of nucleus counterm designed to measure photo-electrically the decrease in intensity of a beam of light which has passed one or more times through an artificially produced fog, are described by L.W. Pollak and W.A. Morgan in a paper.

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