db – -Translation – Keybot Dictionary

  Page 10 - Rapport sur ...  

Show textShow cached sourceOpen source URL	dB - abréviation de « décibel », unité de mesure équivalent à 10 fois le logarithme (base 10) d'un rapport.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	MEL - maximum exposure limit. The maximum exposure level allowed by a standard or guideline usually in terms of power density.

  Page 6 - Principes d'ut...  

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Gold et coll. (Go 84) ont observé quun morceau de carton de 3 mm dépaisseur était suffisant pour réduire les NPA de 70 dB entre 20 et 50 kHz. Crabtree et Forshaw (Cr 77) ont construit des enceintes relativement simples pour plusieurs appareils à nettoyer ultrasonores qui avaient produit des niveaux de pression acoustique, pour les ultrasons transmis dans lair, supérieurs à la norme dActon.

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Protective measures are considerably simpler and more economical in the ultrasonic range than in the audible range since the higher ultrasonic frequencies tend to be much more readily absorbed and reflected inward by enclosures. In addition, they are less liable to diffraction through orifices. Gold et al. (Go 84) reported that cardboard 3 mm thick was adequate to reduce SPLs by 70 dB between 20 and 50 kHz. Crabtree and Forshaw (Cr 77) constructed relatively simple enclosures for several ultrasonic cleaners which had yielded airborne ultrasound SPLs greater than Acton's criterion. One enclosure, made of 3/4" plywood, lined with one-inch styrofoam and fitted with a top lid and front panel hinged with piano hinges, was effective in attenuating the SPL from 85 to 55 dB in the 16 kHz 1/3-octave band. Rooms constructed for large cleaners in a hangar were made with simple construction materials such as 1/2" gypsum board and 1/4" plywood. Sealing of the doors was entirely unnecessary and attenuation was at least 40 dB. Acton (Ac 67) described simple protective measures for a bank of ultrasonic cleaners. The enclosure was constructed from polyvinyl chloride and Perspex, with stainless steel runners on the outside of the enclosure for the doors. (These materials were used because they were resistant to the corrosive fumes generated during the washing process.) Although the enclosure was far from perfectly sealed, Acton and Carson (Ac 67) were able to achieve attenuation of approximately 10 dB at 20 kHz and 15 dB at 40 kHz with this shielding, enough to eliminate the subjective effects.

  Page 6 - Principes d'ut...  

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Cette différence est en accord, qualitativement, avec lélévation abrupte du seuil daudition moyen mesurée par Herbetz et Grunter (He 81, He 84), qui passe denviron 75 dB à 17,5 kHz à 115 dB à 22,5 kHz.

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Two other, quite different criteria have also appeared. The U.S. Air Force (USAF 76) retains an 85 dB limit for each 1/3-octave band from 12.5 to 40 kHz. Based on comparisons to some of Skillern's and Acton's spectra giving rise to subjective effects, these limits may be too high in the 16 and 20 kHz bands to adequately protect against subjective effects and unnecessarily restrictive in the 25 to 40 kHz bands. The other guideline has been presented by auf der Maur in his review article (Ma 85). This proposal, which is based on the AU weighted filter suggested by Herbertz (He 84), has apparently been under consideration by several organizations. However, the high levels it allows, such as 105 dB in the 16 kHz band, 120 dB in the 20 kHz band and 140 dB for the 31.5 kHz band, appear to be excessively high when seen in relation to the data on subjective effects. In addition, the levels permitted in the 16 and 20 kHz bands by this guideline are greater than or equal to those for which Grigor'eva and Dobroserdov appear to have observed TTS in their exposed subjects (Gr 66, Do 67). The value of 140 dB is at the lower limit of the range in which observations of mild heating of skin clefts have been reported (Ac 74).

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Cette différence est en accord, qualitativement, avec lélévation abrupte du seuil daudition moyen mesurée par Herbetz et Grunter (He 81, He 84), qui passe denviron 75 dB à 17,5 kHz à 115 dB à 22,5 kHz.

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Two other, quite different criteria have also appeared. The U.S. Air Force (USAF 76) retains an 85 dB limit for each 1/3-octave band from 12.5 to 40 kHz. Based on comparisons to some of Skillern's and Acton's spectra giving rise to subjective effects, these limits may be too high in the 16 and 20 kHz bands to adequately protect against subjective effects and unnecessarily restrictive in the 25 to 40 kHz bands. The other guideline has been presented by auf der Maur in his review article (Ma 85). This proposal, which is based on the AU weighted filter suggested by Herbertz (He 84), has apparently been under consideration by several organizations. However, the high levels it allows, such as 105 dB in the 16 kHz band, 120 dB in the 20 kHz band and 140 dB for the 31.5 kHz band, appear to be excessively high when seen in relation to the data on subjective effects. In addition, the levels permitted in the 16 and 20 kHz bands by this guideline are greater than or equal to those for which Grigor'eva and Dobroserdov appear to have observed TTS in their exposed subjects (Gr 66, Do 67). The value of 140 dB is at the lower limit of the range in which observations of mild heating of skin clefts have been reported (Ac 74).

  Page 6 - Principes d'ut...  

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Toutefois, pour éviter tout danger de réchauffement dans la plage des fréquences ultrasonores, le niveau de pression acoustique linéaire total mesuré ne doit jamais dépasser 137 dB pour toutes les autres parties du corps.

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The limits recommended in this guideline may be exceeded for occupational exposure, if reduction of the SPL via engineering controls is not possible (see 4.2.2. below) and workers are provided with ear protectors that reduce ultrasound levels at their ears to the sound pressure levels given in Table 5. However, in the ultrasonic frequency range, if potential problems due to heating are to be avoided, total linear measured SPL exposure to other parts of the body must never exceed 137 dB. This value is based on the lowest value (140 dB) (see Figure 2) which allegedly has led to mild heating of skin clefts. A safety factor of 3 dB (a factor of 2 in energy) should ensure that no significant heating of a human could occur.

  Page 6 - Principes d'ut...  

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Toutefois, pour éviter tout danger de réchauffement dans la plage des fréquences ultrasonores, le niveau de pression acoustique linéaire total mesuré ne doit jamais dépasser 137 dB pour toutes les autres parties du corps.

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The limits recommended in this guideline may be exceeded for occupational exposure, if reduction of the SPL via engineering controls is not possible (see 4.2.2. below) and workers are provided with ear protectors that reduce ultrasound levels at their ears to the sound pressure levels given in Table 5. However, in the ultrasonic frequency range, if potential problems due to heating are to be avoided, total linear measured SPL exposure to other parts of the body must never exceed 137 dB. This value is based on the lowest value (140 dB) (see Figure 2) which allegedly has led to mild heating of skin clefts. A safety factor of 3 dB (a factor of 2 in energy) should ensure that no significant heating of a human could occur.

  Page 6 - Principes d'ut...  

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Toutefois, pour éviter tout danger de réchauffement dans la plage des fréquences ultrasonores, le niveau de pression acoustique linéaire total mesuré ne doit jamais dépasser 137 dB pour toutes les autres parties du corps.

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The limits recommended in this guideline may be exceeded for occupational exposure, if reduction of the SPL via engineering controls is not possible (see 4.2.2. below) and workers are provided with ear protectors that reduce ultrasound levels at their ears to the sound pressure levels given in Table 5. However, in the ultrasonic frequency range, if potential problems due to heating are to be avoided, total linear measured SPL exposure to other parts of the body must never exceed 137 dB. This value is based on the lowest value (140 dB) (see Figure 2) which allegedly has led to mild heating of skin clefts. A safety factor of 3 dB (a factor of 2 in energy) should ensure that no significant heating of a human could occur.

  Page 5 - Rapport sur l...  

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Comme cette plage est trop sensible pour les mesures près des stations de base cellulaires, le récepteur utilise un atténuateur fixe de 20 décibels (dB) situé entre l'antenne et le premier amplificateur qui ramène la plage de mesure à une gamme de valeurs de 400 fois à 20 millions de fois inférieures à la limite du Code.

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The Analog-band receiver has a power density measurement range of 1.4 x 10-4 W/m2 to 2.8 x 10-9 W/m2. When normalized to the Health Canada Safety Code 6 [Health Canada, 1999] limit of 5.9 W/m 2 for the Analog band, this measurement rage extends from 40 thousand times below to 2 billion times below the SC 6 limit. Since this range is too sensitive for measurements near cellular base stations, the receiver is operated with a 20 decibel (dB) fixed attenuator between the antenna and the first amplifier which shifts the measurement range from 400 times below to 20 million times below the SC6 limit level.

  Page 5 - Rapport sur l...  

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Le gain de signal du récepteur en bande analogique est d'environ 27 dB dans la bande cellulaire analogique. L'atténuation du signal dans la bande de fr&eacu te;quences d'émission SCP de la station de base (1930 - 1975 MHz) est de 38 dB, ce qui donne au récepteur en bande analogique une sélectivité de 65 dB par rapport aux fréquences SCP.

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The signal gain of the Analog-band receiver is approximately 27 dB across the Analog cellular frequency band. The signal attenuation over the PCS base-station transmit band of frequencies (1930 - 1975 MHz) is 38 dB, giving the receiver a 65 dB selectivity in terms of Analog to PCS frequencies. This selectivity allows an input PCS power level of up to -9 dBm before the detection threshold is reached. Further selectivity is obtained from the monopole antenna that is tuned to give a good impedance match to the receiver at Analog frequencies but a poor match at PCS frequencies.

  Page 5 - Rapport sur l...  

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Le gain de signal du récepteur en bande analogique est d'environ 27 dB dans la bande cellulaire analogique. L'atténuation du signal dans la bande de fr&eacu te;quences d'émission SCP de la station de base (1930 - 1975 MHz) est de 38 dB, ce qui donne au récepteur en bande analogique une sélectivité de 65 dB par rapport aux fréquences SCP.

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The signal gain of the Analog-band receiver is approximately 27 dB across the Analog cellular frequency band. The signal attenuation over the PCS base-station transmit band of frequencies (1930 - 1975 MHz) is 38 dB, giving the receiver a 65 dB selectivity in terms of Analog to PCS frequencies. This selectivity allows an input PCS power level of up to -9 dBm before the detection threshold is reached. Further selectivity is obtained from the monopole antenna that is tuned to give a good impedance match to the receiver at Analog frequencies but a poor match at PCS frequencies.

  Page 5 - Rapport sur l...  

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Le gain de signal du récepteur en bande analogique est d'environ 27 dB dans la bande cellulaire analogique. L'atténuation du signal dans la bande de fr&eacu te;quences d'émission SCP de la station de base (1930 - 1975 MHz) est de 38 dB, ce qui donne au récepteur en bande analogique une sélectivité de 65 dB par rapport aux fréquences SCP.

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The signal gain of the Analog-band receiver is approximately 27 dB across the Analog cellular frequency band. The signal attenuation over the PCS base-station transmit band of frequencies (1930 - 1975 MHz) is 38 dB, giving the receiver a 65 dB selectivity in terms of Analog to PCS frequencies. This selectivity allows an input PCS power level of up to -9 dBm before the detection threshold is reached. Further selectivity is obtained from the monopole antenna that is tuned to give a good impedance match to the receiver at Analog frequencies but a poor match at PCS frequencies.

  Page 6 - Rapport sur l...  

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Ces mesures visaient à permettre le moyennage du signal de manière à n'enregistrer que la moyenne temporelle de la densité de puissance. La fréquence de coupure progressive à 3 dB des circuits de filtres passe-bande a été réglée à 30 Hz, ce qui équivaut à une constante temporelle de moyennage d'environ 5 millisecondes.

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For measurements in the City of Ottawa, the GLOBE system antennae/receivers were mounted on the roof of a mini-van and measurements taken while driving. Thus all power densities were measured approximately at head height. In addition, low-pass filter circuits were installed between the outputs of the log amp/detectors and the inputs of the multiplexed analog-to-digital converter (ADC). This was to provide a means of signal averaging so that only the time-average power density is recorded. The 3 dB roll-off frequency of the low-pass filter circuits was set to 30 Hz which is equivalent to an averaging time-constant of approximately 5 milliseconds. This amount of time is more than adequate to average -out the fast and slow envelope variations shown in Fig. 4.

  Page 6 - Principes d'ut...  

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Gold et coll. (Go 84) ont observé quun morceau de carton de 3 mm dépaisseur était suffisant pour réduire les NPA de 70 dB entre 20 et 50 kHz. Crabtree et Forshaw (Cr 77) ont construit des enceintes relativement simples pour plusieurs appareils à nettoyer ultrasonores qui avaient produit des niveaux de pression acoustique, pour les ultrasons transmis dans lair, supérieurs à la norme dActon.

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Protective measures are considerably simpler and more economical in the ultrasonic range than in the audible range since the higher ultrasonic frequencies tend to be much more readily absorbed and reflected inward by enclosures. In addition, they are less liable to diffraction through orifices. Gold et al. (Go 84) reported that cardboard 3 mm thick was adequate to reduce SPLs by 70 dB between 20 and 50 kHz. Crabtree and Forshaw (Cr 77) constructed relatively simple enclosures for several ultrasonic cleaners which had yielded airborne ultrasound SPLs greater than Acton's criterion. One enclosure, made of 3/4" plywood, lined with one-inch styrofoam and fitted with a top lid and front panel hinged with piano hinges, was effective in attenuating the SPL from 85 to 55 dB in the 16 kHz 1/3-octave band. Rooms constructed for large cleaners in a hangar were made with simple construction materials such as 1/2" gypsum board and 1/4" plywood. Sealing of the doors was entirely unnecessary and attenuation was at least 40 dB. Acton (Ac 67) described simple protective measures for a bank of ultrasonic cleaners. The enclosure was constructed from polyvinyl chloride and Perspex, with stainless steel runners on the outside of the enclosure for the doors. (These materials were used because they were resistant to the corrosive fumes generated during the washing process.) Although the enclosure was far from perfectly sealed, Acton and Carson (Ac 67) were able to achieve attenuation of approximately 10 dB at 20 kHz and 15 dB at 40 kHz with this shielding, enough to eliminate the subjective effects.

  Page 6 - Principes d'ut...  

Show textShow cached sourceOpen source URL	La réduction du niveau de pression acoustique aux fréquences ultrasonores devrait être dau moins 14 dB avec les casques protecteurs et les bouchons en caoutchouc et de 24 dB avec les bouchons en mousse (Ac 83).
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	In those cases where engineering controls are not feasible, reduction of sound at the receiver by ear protection for ultrasonic frequencies is simple and effective. The protection for ultrasonic frequencies is expected to be at least 14 dB for ear muffs and rubber ear plugs, and 24 dB for foa m ear plugs (Ac 83).

  Page 6 - Principes d'ut...  

Show textShow cached sourceOpen source URL	La réduction du niveau de pression acoustique aux fréquences ultrasonores devrait être dau moins 14 dB avec les casques protecteurs et les bouchons en caoutchouc et de 24 dB avec les bouchons en mousse (Ac 83).
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	In those cases where engineering controls are not feasible, reduction of sound at the receiver by ear protection for ultrasonic frequencies is simple and effective. The protection for ultrasonic frequencies is expected to be at least 14 dB for ear muffs and rubber ear plugs, and 24 dB for foa m ear plugs (Ac 83).

  Page 2 - Health Insider...  

Show textShow cached sourceOpen source URL	Le bruit se mesure en décibels (dB). Un soupir perceptible correspond à quelque 10 dB et une conversation normale, à environ 60 dB. Le niveau de bruit d'une route importante correspond à environ 75 dB et celui d'une autoroute, entre 80 et 90 dB.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Noise is measured in decibels (dB). An audible whisper registers about 10dB and normal conversation is measured at about 60dB. The noise level on a major road is about 75dB and the noise from a highway ranges from 80 to 90dB. In Canada, all levels of government share responsibility for the control of environmental noise.

  Page 2 - Health Insider...  

Show textShow cached sourceOpen source URL	Le bruit se mesure en décibels (dB). Un soupir perceptible correspond à quelque 10 dB et une conversation normale, à environ 60 dB. Le niveau de bruit d'une route importante correspond à environ 75 dB et celui d'une autoroute, entre 80 et 90 dB.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Noise is measured in decibels (dB). An audible whisper registers about 10dB and normal conversation is measured at about 60dB. The noise level on a major road is about 75dB and the noise from a highway ranges from 80 to 90dB. In Canada, all levels of government share responsibility for the control of environmental noise.

  Page 2 - Health Insider...  

Show textShow cached sourceOpen source URL	Le bruit se mesure en décibels (dB). Un soupir perceptible correspond à quelque 10 dB et une conversation normale, à environ 60 dB. Le niveau de bruit d'une route importante correspond à environ 75 dB et celui d'une autoroute, entre 80 et 90 dB.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Noise is measured in decibels (dB). An audible whisper registers about 10dB and normal conversation is measured at about 60dB. The noise level on a major road is about 75dB and the noise from a highway ranges from 80 to 90dB. In Canada, all levels of government share responsibility for the control of environmental noise.

  Page 2 - Health Insider...  

Show textShow cached sourceOpen source URL	Le bruit se mesure en décibels (dB). Un soupir perceptible correspond à quelque 10 dB et une conversation normale, à environ 60 dB. Le niveau de bruit d'une route importante correspond à environ 75 dB et celui d'une autoroute, entre 80 et 90 dB.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Noise is measured in decibels (dB). An audible whisper registers about 10dB and normal conversation is measured at about 60dB. The noise level on a major road is about 75dB and the noise from a highway ranges from 80 to 90dB. In Canada, all levels of government share responsibility for the control of environmental noise.

  Page 5 - Principes d'ut...  

Show textShow cached sourceOpen source URL	Tableau 3 Niveaux de pression acoustique, en dB, pour divers appareils commerciaux
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Table 3. Exposure SPLs in dB for Various Commercial Devices.

  Page 6 - Principes d'ut...  

Show textShow cached sourceOpen source URL	NPA (dB)
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	SPL(dB)

  Diéthylèneglycol - clas...  

Show textShow cached sourceOpen source URL	O'brien KL, Selanikio JD, Hecdivert C, Placide MF, Louis M, Barr DB, Barr JR, Hospedales CJ, Lewis MJ, Schwartz BPhilen RM, St Victor S, Espindola J, Needham LL, Denerville K. : Epidemic of paediatric deaths from acute renal failure caused by diethylene glycol poisoning.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	O'brien KL, Selanikio JD, Hecdivert C, Placide MF, Louis M, Barr DB, Barr JR, Hospedales CJ, Lewis MJ, Schwartz BPhilen RM, St Victor S, Espindola J, Needham LL, Denerville K.: Epidemic of paediatric deaths from acute renal failure caused by diethylene glycol poisoning. Acute renal investigation team. JAMA 1998;279(15):1175-80.

  Page 2 - Health Insider...  

Show textShow cached sourceOpen source URL	Le bruit se mesure en décibels (dB). Un soupir perceptible correspond à quelque 10 dB et une conversation normale, à environ 60 dB. Le niveau de bruit d'une route importante correspond à environ 75 dB et celui d'une autoroute, entre 80 et 90 dB.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Noise is measured in decibels (dB). An audible whisper registers about 10dB and normal conversation is measured at about 60dB. The noise level on a major road is about 75dB and the noise from a highway ranges from 80 to 90dB. In Canada, all levels of government share responsibility for the control of environmental noise.

  Page 4 - L'acide (4-chl...  

Show textShow cached sourceOpen source URL	Il faut noter que le MCPA est habituellement utilisé avec d'autres herbicides du type phénoxy tels que l'acide dichloro-2,4 phénoxyacétique (2,4-D), l'acide (2,4-dichlorophénoxy) butyrique (2,4-DB), l'acide (R)(+)-2-(4-chloro-2-méthylphénoxy)propanoïque (MCPP-p) et l'acide 4-(2-méthyl-4-chlorophénoxy)butyrique (MCPB) (U.S. EPA, 2004b).
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	It should be noted that MCPA is usually applied along with other phenoxy herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D), 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB), (R)(+)-2-(4-chloro-2-methylphenoxy)propanoic acid (also known as mecoprop-p or MCPP-p) and 4-(2-methyl-4-chlorophenoxy)butyric acid (MCPB) (U.S. EPA, 2004b).

  Principes d'utilisation...  

Show textShow cached sourceOpen source URL	Tableau 3. Niveaux de pression acoustique, en dB, pour divers appareils commerciaux
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Table 3 Exposure SPLs in dB for Various Commercial Devices

  Page 5 - Rapport sur l...  

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Cela est particulièrement important lorsqu'on mesure un signal faible en bande SCP en présence de signaux forts en bande analogique. Les essais ont montré que des niveaux de signaux, en bande analogique, atteignant jusqu'à -9,0 dBm ne produisaient pas de sortie détectable avec cette configuration.

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The block diagram of the PCS-band receiver is given in Figure 2(b). The receiver has a different arrangement of the filters than the Analog-band one in order to pr event harmonics of analog-band signals from producing false outputs. This is especially important in situations where a weak PCS-band signal is being measured in the presence of strong Analog-band signals. Tests showed that signal levels, in the Analog band, of up to -9.0 dBm produced no detectable output with this arrangement. The selectivity of the PCS-band receiver to Analog-band signals was measured to be 76 dB.

  Page 6 - Principes d'ut...  

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Gold et coll. (Go 84) ont observé quun morceau de carton de 3 mm dépaisseur était suffisant pour réduire les NPA de 70 dB entre 20 et 50 kHz. Crabtree et Forshaw (Cr 77) ont construit des enceintes relativement simples pour plusieurs appareils à nettoyer ultrasonores qui avaient produit des niveaux de pression acoustique, pour les ultrasons transmis dans lair, supérieurs à la norme dActon.

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Protective measures are considerably simpler and more economical in the ultrasonic range than in the audible range since the higher ultrasonic frequencies tend to be much more readily absorbed and reflected inward by enclosures. In addition, they are less liable to diffraction through orifices. Gold et al. (Go 84) reported that cardboard 3 mm thick was adequate to reduce SPLs by 70 dB between 20 and 50 kHz. Crabtree and Forshaw (Cr 77) constructed relatively simple enclosures for several ultrasonic cleaners which had yielded airborne ultrasound SPLs greater than Acton's criterion. One enclosure, made of 3/4" plywood, lined with one-inch styrofoam and fitted with a top lid and front panel hinged with piano hinges, was effective in attenuating the SPL from 85 to 55 dB in the 16 kHz 1/3-octave band. Rooms constructed for large cleaners in a hangar were made with simple construction materials such as 1/2" gypsum board and 1/4" plywood. Sealing of the doors was entirely unnecessary and attenuation was at least 40 dB. Acton (Ac 67) described simple protective measures for a bank of ultrasonic cleaners. The enclosure was constructed from polyvinyl chloride and Perspex, with stainless steel runners on the outside of the enclosure for the doors. (These materials were used because they were resistant to the corrosive fumes generated during the washing process.) Although the enclosure was far from perfectly sealed, Acton and Carson (Ac 67) were able to achieve attenuation of approximately 10 dB at 20 kHz and 15 dB at 40 kHz with this shielding, enough to eliminate the subjective effects.

  Page 4 - Principes d'ut...  

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(Al 48). Ce rapport fait état d'expositions à un niveau de pression acoustique de 165 dB. A ce niveau, le réchauffement local dans les fentes entre les doigts a causé des brûlures presque instantanément.

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Further information on the ultrasonic heating of humans is found in the incidental human exposures reported in the work of Allen et al., in which an SPL of 165 dB was used (Al 48). Local heating in the crevices between fingers caused burns almost instantly at these levels. Painful heating occurred after several seconds of exposure of broader surfaces such as the palm of the hand. In addition, Acton (Ac 74) has reported on unpublished work by Parrack indicating that mild heating in skin clefts has been observed in the SPL range of 140-150 dB. Other non-auditory effects at these high levels included extremely disagreeable sensations in the nasal passages.

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Show textShow cached sourceOpen source URL	Tableau 2. Niveaux de pression acoustique choisis, en dB, à la position de l'opérateur, pour une exposition à des sources ultrasonores industrielles, dansdes bandes de tiers d'octave
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	Table 2 Selected SPLs in dB at the Operator's Position in 1/3 Octave Bands from Industrial Ultrasonic Sources

  Page 4 - Principes d'ut...  

Show textShow cached sourceOpen source URL	2. Dans l'air, la conversion entre le niveau de pression acoustique, NPA, en dB, et l'intensité, I, en W/cm2, est donnée par I2 - 10((NPA-160)/10). Un NPA de 160 dB correspond donc à une intensité de 1 W/cm2.
Compare text pagesCompare HTM pagesOpen source URLOpen target URLDefine hc-sc.gc.ca as primary domain	2 In air, the conversion from SPL in dB to intensity, I, in W/cm2 is given by I =10((SPL-160)/10). Thus, a SPL of 160 dB has an intensity of 1 W/cm2.