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Detalles de la revista
Formato
Revista
eISSN
2719-9509
Publicado por primera vez
01 Jan 1992
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

Volumen 8 (1975): Edición 2 (May 1975)

Detalles de la revista
Formato
Revista
eISSN
2719-9509
Publicado por primera vez
01 Jan 1992
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

11 Artículos
Acceso abierto

A Thirty-Port Smoking Machine for Continuous Smoke Generation

Publicado en línea: 14 Aug 2014
Páginas: 53 - 59

Resumen

Abstract

Experience gained from a recent evaluation of smoking machines has been applied in the design of a sophisticated automatic smoking machine. Utilizing a reverse puff mechanism, a continuous or intermittent smoke stream is generated, diluted to selected concentration levels and channelled to multiple exposure apparatus. AlI functions are completely controlled by digital electronics as is the detection of faults in the system. Analysis of the smoke produced indicates that it is not chemically different from the smoke delivered by other types of apparatus

Acceso abierto

Multiple Capillary Pressure Drop Standards

Publicado en línea: 14 Aug 2014
Páginas: 60 - 64

Resumen

Abstract

This paper describes a simple device, consisting of a collection of glass capillary tubes, which can be used as a stable, pressure insensitive standard for calibrating pressure drop machines. For air flowing through a single capillary tube of the proper dimensions to give a pressure drop similar to that of a filter rod, the Reynolds number is about 2000, the boundary between laminar and turbulent flow. Since turbulent flow gives pressure drops which vary with atmospheric pressure, it is desirable to reduce this quantity to a level where laminar flow is always present. This can be accomplished by distributing the flow among 10 parallel capillaries of very small diameter. The capillaries were formed by drawing pyrex tubing on a Hupe glass drawing machine to a finished internaI diameter of .44 mm. Ten Iengths of this capillary were mounted in 8 mm tubing and were encased in a clear resin. After polymerization of the resin, the composite rod was sawed into appropriate lengths and cleaned in an ultrasonic bath. Microscopic examination of the finished tubes showed that each capillary was a clean, smooth-walled tube with a sharp entrance and exit. Calculation of the Reynolds number for the composite capillary gave a value of 314, which is well within the Iaminar flow region. The agreement between measured pressure drops of these standards and those calculated using Poiseuille's Iaw with an entry and exit correction is excellent. Daily measurements of the pressure drop of these standard tubes for a period of a month were conducted, and the random variability was found to be 1 % or Iess. Measurements of the pressure drop of these tubes at various pressures and temperatures covering the range of normaI laboratory conditions also demonstrated a lack of significant variability. Fouling of the tubes from atmospheric dust was not found to be a significant factor

Acceso abierto

Study of Sorption Processes in Cigarette Filter Materials

Publicado en línea: 14 Aug 2014
Páginas: 65 - 69

Resumen

Abstract

A method for studying adsorption-desorption kinetics in porous materials is described. A fixed bed of the adsorbent is challenged with a constant concentration of vapour in an inert carrier and the effluent vapour concentration is monitored as a function of time by using a gas chromatograph. Results obtained with commerciaI filters and nicotine vapour are reported. They fit a mathematical model based on a first-order, reversible rate-controlling process and a linear adsorption isotherm

Acceso abierto

The Control of Cigarette Smoke Deliveries Using Heat-Shrinkable Films

Publicado en línea: 14 Aug 2014
Páginas: 70 - 77

Resumen

Abstract

A ventilating filter for cigarettes has been developed which reduces the delivery of smoke constituents from the final two to three puffs. Since the normaI delivery for these three puffs can account for up to half the total particulate matter and nicotine delivered by the whole cigarette, usefuI reductions per cigarette can be produced. The ventilating filter consists of cellulose acetate tow wrapped in heat-shrinkable film and attached to a tobacco rod using perforated tipping paper. When the cigarette is smoked, the perforations remain closed by contact with the impermeable film until transfer of heat to the filter is sufficient to soften the filter tow and shrink the film. Ventilating air now enters the cigarette and reduces the smoke deliveries. The effectiveness of the ventilating filter is increased by using films which have a low shrink temperature, high shrink tension and a high degree of biaxiaI shrinkage. Increases in filter plasticiser level, tipping perforation area and puff volume improve the effectiveness of the ventilating filter but increases in cigarette paper porosity and tobacco butt length reduce the effectiveness

Acceso abierto

Thermal Decomposition of Tobacco: V. Influence of Temperature on the Formation of Carbon Monoxide and Carbon Dioxide

Publicado en línea: 14 Aug 2014
Páginas: 78 - 83

Resumen

Abstract

The temperature-yield profiles of CO and CO2 have been obtained by the analysis of the effluent gas from the differential thermaI analysis (DTA) and pyrolysis gas chromatography (PGC) of tobacco. The CO profiles obtained from DTA show that CO is continuously generated from 140° to 950°C and has four temperatures for maximum formation: 240°, 310°, 450° and 690°C. These maxima correspond to those exhibited by the effluent gas detection (EGD) curve. AIl data show that the major portion of CO is formed above 650°C, even though the weight loss of tobacco at these temperatures is less than 10 %. The CO2 profile obtained from thermal analysis also corresponds to effluent gas detection curve and shows that the majority of CO2 is formed below 500°C. The profiles for CO2 from PGC indicate that the reduction of CO2 by carbon to form CO at temperatures above 600°C are not significant under these pyrolysis conditions. Analysis of the gas phase from the thermal analysis of extracted tobaccos shows that this method is a means for studying the influence of product modification on the formation of CO and CO2 especially at lower temperatures. The PGC of these modified tobaccos appears to be of little value for studying the effect of product modification on the formation of CO and CO2

Acceso abierto

Comparison of Pyrolytic Products from Flue-Cured Tobacco Leaf and a Reconstituted Tobacco Sheet

Publicado en línea: 14 Aug 2014
Páginas: 84 - 88

Resumen

Abstract

Pyrolytic products of commercial tobacco sheet, flue-cured tobacco leaf, and stems were compared. The yields of acids, bases, neutrals, and phenolics were determined. The neutrals were further characterized by chromatography in order to examine pyrolysis fractions corresponding to biologically active cigarette smoke fractions. Individual phenols, carboxylic acids, polynuclear aromatic hydrocarbons (PAH), and nicotine were determined for sheet and leaf pyrolyzate. Analyses of constituents of various pyrolyzate fractions indicated significantly lower amounts of phenols, PAH, and nicotine in sheet and stem pyrolyzates than in leaf pyrolyzates

Acceso abierto

The Distribution with Respect to Smoke Particle Size of Dotriacontane, Hexadecane and Decachlorobiphenyl Added to Cigarettes

Publicado en línea: 14 Aug 2014
Páginas: 89 - 92

Resumen

Abstract

When studying the distribution of smoke deposited in the lung, it is necessary to use a tracer which indicates the levels of particulate matter deposited at various sites. Because the site of deposition can be dependent on the particle size of the aerosol, it is important that the tracer should be uniformly distributed with respect to particle size, otherwise the levels of particulate matter may be wrongly estimated. The distributions in the smoke from a cigarette containing flue-cured tobacco of three possible tracers (dotriacontane, hexadecane and decachlorobiphenyl) have been measured; alI three show a slight dependence but probably not sufficient to exclude them from possible use in inhalation studies. However, because of the different environment which exists in the lung, and the possible dependence of the results on the type of tobacco, it should not be assumed that there are no selective effects

Acceso abierto

Homogenized Leaf Curing: II. Bright Tobacco

Publicado en línea: 14 Aug 2014
Páginas: 93 - 101

Resumen

Acceso abierto

Evaluations of Cigarettes Made with Mold-Damaged and Nondamaged Flue-cured Tobacco

Publicado en línea: 14 Aug 2014
Páginas: 102 - 106

Resumen

Abstract

FIue-cured tobacco damaged by species of Aspergillus from commerciaI and experimental sources was shredded and made into cigarettes. Paired samples of nondamaged tobaccos served as controls. Subsamples of cigarettes were analysed for viable fungal propagules/g, 39 organic and inorganic compounds in the smoke and smoke condensates, and taste preference. PrincipaI fungi associated with leaves and shreds of mold-damaged tobacco were Aspergillus repens, A. ruber, and A. niger. Except for the originaI differences in the nicotine content and in the tar, there were no significant differences in total particulate matter nor in the amount of specific vapour phase components measured in the smoke from cigarettes made with mold-damaged and nondamaged tobaccos. Smoke panelists distinguished between cigarettes made with mold-damaged and nondamaged tobaccos and preferred cigarettes made with the latter. Viable fungus spores passed through the tobacco cylinder from lighted and nonlighted cigarettes. These data suggest the use of mold-damaged tobacco in cigarette manufacturing is to be avoided because of off-flavours and because the fungi isolated are common allergens to the respiratory tract of humans

Acceso abierto

CORESTA - Method No. 1 Method of the determination of Dithiocarbamats in tobacco (revised version) / CORESTA – Methode Nr. 1 Methode für die Bestimmung von Dithiocarbamaten in Tabak (revidierte Version)

Publicado en línea: 14 Aug 2014
Páginas: 107 - 108

Resumen

Abstract

1. Prinzip

2. Reagenzien

3. Apparatur

4. Methode

5. Eichung

6. Berechnung

Acceso abierto

CORESTA - Method No. 2 Method for the determination of sediments on organochlor-pestizides in tobacco / CORESTA - Methode Nr. 2 Methode für die Bestimmung von Rückständen an Organochlor-Pestiziden in Tabak

Publicado en línea: 14 Aug 2014
Páginas: 109 - 111

Resumen

Abstract

1. Anwendungsbereich

2. Apparatur und Glasgeräte

3. Reagenzien

4. Eichlösungen

5. Vorbereitung der Tabakproben

6. Extraktion

7. Gaschromatographie

11 Artículos
Acceso abierto

A Thirty-Port Smoking Machine for Continuous Smoke Generation

Publicado en línea: 14 Aug 2014
Páginas: 53 - 59

Resumen

Abstract

Experience gained from a recent evaluation of smoking machines has been applied in the design of a sophisticated automatic smoking machine. Utilizing a reverse puff mechanism, a continuous or intermittent smoke stream is generated, diluted to selected concentration levels and channelled to multiple exposure apparatus. AlI functions are completely controlled by digital electronics as is the detection of faults in the system. Analysis of the smoke produced indicates that it is not chemically different from the smoke delivered by other types of apparatus

Acceso abierto

Multiple Capillary Pressure Drop Standards

Publicado en línea: 14 Aug 2014
Páginas: 60 - 64

Resumen

Abstract

This paper describes a simple device, consisting of a collection of glass capillary tubes, which can be used as a stable, pressure insensitive standard for calibrating pressure drop machines. For air flowing through a single capillary tube of the proper dimensions to give a pressure drop similar to that of a filter rod, the Reynolds number is about 2000, the boundary between laminar and turbulent flow. Since turbulent flow gives pressure drops which vary with atmospheric pressure, it is desirable to reduce this quantity to a level where laminar flow is always present. This can be accomplished by distributing the flow among 10 parallel capillaries of very small diameter. The capillaries were formed by drawing pyrex tubing on a Hupe glass drawing machine to a finished internaI diameter of .44 mm. Ten Iengths of this capillary were mounted in 8 mm tubing and were encased in a clear resin. After polymerization of the resin, the composite rod was sawed into appropriate lengths and cleaned in an ultrasonic bath. Microscopic examination of the finished tubes showed that each capillary was a clean, smooth-walled tube with a sharp entrance and exit. Calculation of the Reynolds number for the composite capillary gave a value of 314, which is well within the Iaminar flow region. The agreement between measured pressure drops of these standards and those calculated using Poiseuille's Iaw with an entry and exit correction is excellent. Daily measurements of the pressure drop of these standard tubes for a period of a month were conducted, and the random variability was found to be 1 % or Iess. Measurements of the pressure drop of these tubes at various pressures and temperatures covering the range of normaI laboratory conditions also demonstrated a lack of significant variability. Fouling of the tubes from atmospheric dust was not found to be a significant factor

Acceso abierto

Study of Sorption Processes in Cigarette Filter Materials

Publicado en línea: 14 Aug 2014
Páginas: 65 - 69

Resumen

Abstract

A method for studying adsorption-desorption kinetics in porous materials is described. A fixed bed of the adsorbent is challenged with a constant concentration of vapour in an inert carrier and the effluent vapour concentration is monitored as a function of time by using a gas chromatograph. Results obtained with commerciaI filters and nicotine vapour are reported. They fit a mathematical model based on a first-order, reversible rate-controlling process and a linear adsorption isotherm

Acceso abierto

The Control of Cigarette Smoke Deliveries Using Heat-Shrinkable Films

Publicado en línea: 14 Aug 2014
Páginas: 70 - 77

Resumen

Abstract

A ventilating filter for cigarettes has been developed which reduces the delivery of smoke constituents from the final two to three puffs. Since the normaI delivery for these three puffs can account for up to half the total particulate matter and nicotine delivered by the whole cigarette, usefuI reductions per cigarette can be produced. The ventilating filter consists of cellulose acetate tow wrapped in heat-shrinkable film and attached to a tobacco rod using perforated tipping paper. When the cigarette is smoked, the perforations remain closed by contact with the impermeable film until transfer of heat to the filter is sufficient to soften the filter tow and shrink the film. Ventilating air now enters the cigarette and reduces the smoke deliveries. The effectiveness of the ventilating filter is increased by using films which have a low shrink temperature, high shrink tension and a high degree of biaxiaI shrinkage. Increases in filter plasticiser level, tipping perforation area and puff volume improve the effectiveness of the ventilating filter but increases in cigarette paper porosity and tobacco butt length reduce the effectiveness

Acceso abierto

Thermal Decomposition of Tobacco: V. Influence of Temperature on the Formation of Carbon Monoxide and Carbon Dioxide

Publicado en línea: 14 Aug 2014
Páginas: 78 - 83

Resumen

Abstract

The temperature-yield profiles of CO and CO2 have been obtained by the analysis of the effluent gas from the differential thermaI analysis (DTA) and pyrolysis gas chromatography (PGC) of tobacco. The CO profiles obtained from DTA show that CO is continuously generated from 140° to 950°C and has four temperatures for maximum formation: 240°, 310°, 450° and 690°C. These maxima correspond to those exhibited by the effluent gas detection (EGD) curve. AIl data show that the major portion of CO is formed above 650°C, even though the weight loss of tobacco at these temperatures is less than 10 %. The CO2 profile obtained from thermal analysis also corresponds to effluent gas detection curve and shows that the majority of CO2 is formed below 500°C. The profiles for CO2 from PGC indicate that the reduction of CO2 by carbon to form CO at temperatures above 600°C are not significant under these pyrolysis conditions. Analysis of the gas phase from the thermal analysis of extracted tobaccos shows that this method is a means for studying the influence of product modification on the formation of CO and CO2 especially at lower temperatures. The PGC of these modified tobaccos appears to be of little value for studying the effect of product modification on the formation of CO and CO2

Acceso abierto

Comparison of Pyrolytic Products from Flue-Cured Tobacco Leaf and a Reconstituted Tobacco Sheet

Publicado en línea: 14 Aug 2014
Páginas: 84 - 88

Resumen

Abstract

Pyrolytic products of commercial tobacco sheet, flue-cured tobacco leaf, and stems were compared. The yields of acids, bases, neutrals, and phenolics were determined. The neutrals were further characterized by chromatography in order to examine pyrolysis fractions corresponding to biologically active cigarette smoke fractions. Individual phenols, carboxylic acids, polynuclear aromatic hydrocarbons (PAH), and nicotine were determined for sheet and leaf pyrolyzate. Analyses of constituents of various pyrolyzate fractions indicated significantly lower amounts of phenols, PAH, and nicotine in sheet and stem pyrolyzates than in leaf pyrolyzates

Acceso abierto

The Distribution with Respect to Smoke Particle Size of Dotriacontane, Hexadecane and Decachlorobiphenyl Added to Cigarettes

Publicado en línea: 14 Aug 2014
Páginas: 89 - 92

Resumen

Abstract

When studying the distribution of smoke deposited in the lung, it is necessary to use a tracer which indicates the levels of particulate matter deposited at various sites. Because the site of deposition can be dependent on the particle size of the aerosol, it is important that the tracer should be uniformly distributed with respect to particle size, otherwise the levels of particulate matter may be wrongly estimated. The distributions in the smoke from a cigarette containing flue-cured tobacco of three possible tracers (dotriacontane, hexadecane and decachlorobiphenyl) have been measured; alI three show a slight dependence but probably not sufficient to exclude them from possible use in inhalation studies. However, because of the different environment which exists in the lung, and the possible dependence of the results on the type of tobacco, it should not be assumed that there are no selective effects

Acceso abierto

Homogenized Leaf Curing: II. Bright Tobacco

Publicado en línea: 14 Aug 2014
Páginas: 93 - 101

Resumen

Acceso abierto

Evaluations of Cigarettes Made with Mold-Damaged and Nondamaged Flue-cured Tobacco

Publicado en línea: 14 Aug 2014
Páginas: 102 - 106

Resumen

Abstract

FIue-cured tobacco damaged by species of Aspergillus from commerciaI and experimental sources was shredded and made into cigarettes. Paired samples of nondamaged tobaccos served as controls. Subsamples of cigarettes were analysed for viable fungal propagules/g, 39 organic and inorganic compounds in the smoke and smoke condensates, and taste preference. PrincipaI fungi associated with leaves and shreds of mold-damaged tobacco were Aspergillus repens, A. ruber, and A. niger. Except for the originaI differences in the nicotine content and in the tar, there were no significant differences in total particulate matter nor in the amount of specific vapour phase components measured in the smoke from cigarettes made with mold-damaged and nondamaged tobaccos. Smoke panelists distinguished between cigarettes made with mold-damaged and nondamaged tobaccos and preferred cigarettes made with the latter. Viable fungus spores passed through the tobacco cylinder from lighted and nonlighted cigarettes. These data suggest the use of mold-damaged tobacco in cigarette manufacturing is to be avoided because of off-flavours and because the fungi isolated are common allergens to the respiratory tract of humans

Acceso abierto

CORESTA - Method No. 1 Method of the determination of Dithiocarbamats in tobacco (revised version) / CORESTA – Methode Nr. 1 Methode für die Bestimmung von Dithiocarbamaten in Tabak (revidierte Version)

Publicado en línea: 14 Aug 2014
Páginas: 107 - 108

Resumen

Abstract

1. Prinzip

2. Reagenzien

3. Apparatur

4. Methode

5. Eichung

6. Berechnung

Acceso abierto

CORESTA - Method No. 2 Method for the determination of sediments on organochlor-pestizides in tobacco / CORESTA - Methode Nr. 2 Methode für die Bestimmung von Rückständen an Organochlor-Pestiziden in Tabak

Publicado en línea: 14 Aug 2014
Páginas: 109 - 111

Resumen

Abstract

1. Anwendungsbereich

2. Apparatur und Glasgeräte

3. Reagenzien

4. Eichlösungen

5. Vorbereitung der Tabakproben

6. Extraktion

7. Gaschromatographie

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