| 1. |
- Burström, Lage, et al.
(författare)
-
A follow-up study of welders’ exposure to vibration in a heavy engineering production workshop
- 2010
-
Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - : Sage Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 29:1, s. 33-39
-
Tidskriftsartikel (refereegranskat)abstract
- Manual work involving vibrating power tools is associated with symptoms that include vascular, neurological and musculoskeletal disorders. This study examines the vibration exposure of welders to determine the change between 1987 and 2008. Vibration measurements on handheld tools were used to evaluate the acceleration and the daily exposure time was determined by subjective rating. From these data, the 8-hour equivalent vibration exposure A(8), has been calculated. During the period, the A(8) decreased from 3.9 m/s2 to 1.9 m/s2. It was concluded that this decrease is the result of fewer vibrating tools and a decrease in daily exposure time. Although the daily vibration exposure has decreased over the study time, for some welders the daily vibration exposure A(8) is still above the action value set by the EU directive on vibration. This means more effort should be spent to decrease vibration exposure.
|
|
| 2. |
|
|
| 3. |
- Bengtsson Ryberg, Johanna, 1974, et al.
(författare)
-
Low frequency noise in a paper mill control room
- 2007
-
Ingår i: Journal of Low Frequency Noise, Vibration and Active Control. - : SAGE Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 26:3, s. 165-176
-
Tidskriftsartikel (refereegranskat)abstract
- This field study aimed to evaluate the prevalence of annoyance and disturbance and the subjective perception of the sound environment due to noise, in an old and a new control room at a large paper mill. Working in a control room requires sustained attention and concentration and, in the case of error messages, rapid and correct decisions. In this study, the personnel's responses were collected by questionnaire, and detailed sound measurements were taken in both control rooms. The A-weighted sound pressure level in the new control room was 54.9 dB, a reduction from the 63.5 dB measured in the old room, and the C-weighted sound pressure level was 66.8 dB, a reduction from the 75.2 dB measured in the old room. The new control room was rated as being a less noisy environment; however, the personnel did complain about noise from other computers/equipment, radios, and the new laboratory.
|
|
| 4. |
- Burström, Lage
(författare)
-
Measurement of the mechanical energy absorbation in the hand and arm whilst using vibrating tools
- 1990
-
Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - : SAGE Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 9:1, s. 1-14
-
Tidskriftsartikel (refereegranskat)abstract
- The mechanical energy absorption in the human hand and arm during exposure to simulated vibration from five common types of hand-held tools within the frequency range of 5 to 1500 Hz, has been directly measured and indirectly determined. The study was carried out on ten healthy subjects, five males and five females. A special handle was used during the measurements. The influence of various experimental conditions, such as vibration level, vibration direction and grip force were also studied. The results show that the energy absorption depends upon the frequency spectra of the tools. The differences between the amount of absorbed energy for the hand-held tools correspond to a factor 3.1 although the frequency weighted acceleration is equal. Furthermore, the results show that experiments conducted with different exposure directions have a significant influence on the amount of absorbed energy. On the other hand, the grip force has only a minor influence. The results also show that it is possible to theoretically calculate the amount of absorbed energy by using the vibration characteristics for the hand-held tool and the mechanical characteristics of the hand and arm.
|
|
| 5. |
- Genell, Anders, 1974, et al.
(författare)
-
Components in evaluation of complex interior truck sounds
- 2006
-
Ingår i: Journal of Low Frequency Noise and Vibration. - 0263-0923. ; 25:4, s. 227-237
-
Tidskriftsartikel (refereegranskat)abstract
- In order to investigate influences on assessment of interior truck sounds two experiments have been carried out with emphasis on the low frequency content. In the first experiment the participants were presented with recorded sound from the interior of a truck cabin, with different alterations of the low frequency content. In the second experiment the balance between low and high frequency content was altered for the recorded sounds. Three main dimensions important for the assessment of truck sounds were found: an Annoyance factor, a Wakefulness factor and a Quality factor. Additionally it was found that a wellsuited spectral balance could improve positive impressions of truck sound.
|
|
| 6. |
- Håkansson, Lars, et al.
(författare)
-
Adaptive Feedback Control of Machine-Tool Vibration based on The Filtered-x LMS Algorithm
- 1998
-
Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - 0263-0923. ; 17:4, s. 199-213
-
Tidskriftsartikel (refereegranskat)abstract
- Adaptive feedback control of tool vibrations during metal cutting in a lathe has been investigated. The vibrations were controlled in the primary cutting direction and the control is based on the filtered-x LMS-algorithm. It was found that the adaptive feedback control can achieve a reduction of the tool vibrations with up to 35 dB at 1.7 kHz and simultaneously with approximately 30 dB at 3.1 kHz. A significant improvement of the workpiece surface was experienced together with a substantial reduction of the acoustic noise level with adaptive feedback control. Tool life is also expected to be extended and the material removal rate can probably be increased.
|
|
| 7. |
- Khan, Shafiquzzaman, et al.
(författare)
-
Effects of vibration on sedentary activities in passenger trains
- 2007
-
Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - : SAGE Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 26:1, s. 43-55
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of vibration on train passengers' sedentary activities were investigated with a questionnaire survey as well as onboard vibration measurements. Three types of Swedish inter-regional trains were studied on four different lines. 330 passengers were randomly selected for the questionnaire survey. The vibration measurements were made at five positions around a passenger seat above the bogie during normal service. The vibration data were weighted according to ISO 2631-1 and the older German (Sperling) Ride Index Wz. Two-thirds of the passengers reported difficulties in performing sedentary activities such as reading and writing due to vibration and shocks. However, the standardized measurements did not reveal any severe discomfort values due to the vibration. This reveals that ISO and Wz standards do not evaluate vibrations effect on sedentary activities correctly. This also indicates that even low levels of vibration can reduce the ability to perform sedentary activities. Both chair and table produced more vibration than the floor. The spectral analysis showed that the chair had nearly the same frequency content as the floor, below 10 Hz. This range is critical since it coincides with the most vulnerable range for reading and writing as well as the perception of ride comfort.
|
|
| 8. |
- Körning-Ljungberg, Jessica
(författare)
-
Combined exposures of noise and whole-body vibration and the effects on psychological responses : a review
- 2008
-
Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - : SAGE Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 27:4, s. 267-279
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this review is to shed light on a research area that concerns the studies of psychological responses to combined exposures of noise and whole-body vibration (WBV). Vehicle drivers are a group of workers that are often exposed to multiple stressors like noise, WBV and mental loads. Degraded performance because of environmental stressors may lead to injury or accidents. Standards that govern health risk assessment don't take into consideration the complexities of these multiple exposure environments (ISO 1997a, ISO 1999). Some studies have shown that the effect of one factor may be different than the effect of two factors presented together. For example, negative combined effects have been found in tracking tasks (Sommer and Harris, 1973), in arithmetic tasks (Harris and Schoenberger, 1980), as well as in subjective ratings (Ljungberg, Neely, Lundström, 2004), although in many of the studies the noise and WBV stimuli have been very unlike those that can be found in real working environments. Applying methods from the "irrelevant sound" paradigm (e.g. Jones, 1990) by using short-term memory tasks with a serial component as well as focus on frequencies rather than level has been revealed to tap the resources both objectively and subjectively more in both noise and WBV studies (e.g. Banbury et al. 2001; Kjellberg, 1990) Still, most experiments that have been conducted have focused on rather short exposure times in controlled laboratory settings. Taking into consideration to use longer exposure times might also reveal other results since longer exposure times may be negatively related to sensitivity to noise and WBV (Abbate et al. 2004; Neely, Lundström, and Björkvist, 2002; Weinstein, 1978)
|
|
| 9. |
- Körning-Ljungberg, Jessica, et al.
(författare)
-
Effects on spatial skills after exposure to low frequency noise
- 2004
-
Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - : SAGE Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 23:1, s. 1-6
-
Tidskriftsartikel (refereegranskat)abstract
- A study of spatial skills was conducted with 27 male and 27 female participants. The aim of the study was to examine the post-exposure effect of a complex low frequency noise (21 Hz) on a mental rotation task. It was hypothesised that reaction time and number of errors would increase after 20 minutes exposure to noise exposure compared to performance after a control condition, and that groups exposed to higher intensity noise would exhibit greater impairment. Three groups of participants were exposed to a control condition and a noise condition (either, 77, 81 or 86 dB (A)). After each exposure, subjects completed a mental rotation task where the stimulus consisted of one of three letters presented in five different rotations, showed either normally or mirrored. The participants were asked to respond as quickly and accurately as possible, affirmatively if the letter presented was not mirrored and negatively if it was mirrored. Statistical analysis revealed that the medium intensity level generated significant post-exposure effects while no effects were seen at the low or high intensity levels
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Lundquist, Pär, 1973-, et al.
(författare)
-
Low frequency noise and annoyance in classroom
- 2000
-
Ingår i: Journal of Low Frequency Noise Vibration and Active Control. - London : Multi-Science Publishing. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 19:4, s. 175-181
-
Tidskriftsartikel (refereegranskat)abstract
- The most common method for noise assessment is the A-weighted sound pressure level. The question has been raised as to whether the frequency weighting with an A-filter gives a correct result when assessing the annoyance response to noise containing strong low frequency noise (LFN) components. One method suggested to identify LFN is the dB(C) – dB(A) difference. The aims of this study are to investigate if background noise in Swedish elementary schools is to be considered as LFN, further to test the hypothesis that students exposed to audible LFN at high levels are more annoyed than students exposed to LFN at lower levels. The results indicate that the noise in 16 out of 22 classrooms should be considered as LFN. The analysis did not show any difference in rated annoyance between students exposed to high LFN levels and students exposed to low LFN levels.
|
|
| 13. |
- Pedersen Sejer, C., et al.
(författare)
-
A detailed study of low-frequency noise complaints
- 2008
-
Ingår i: Journal of Low Frequency Noise, Vibration and Active Control. - : SAGE Publications. - 0263-0923 .- 1461-3484 .- 2048-4046. ; 27:1, s. 1-33
-
Tidskriftsartikel (refereegranskat)abstract
- From 203 cases of low-frequency complaints a random selection of twenty-one cases were investigated. The main aim was to answer the question whether the annoyance is caused by an external physical sound or by a perceived but physically non-existing sound, i.e. low-frequency tinnitus. Noise recordings were made in the homes of the complainants, and the complainants were exposed to these in blind test listening experiments. Furthermore, the low-frequency hearing function of the complainants was investigated, and characteristics of the annoying sound were matched. The results showed that some of the complainants are annoyed by a physical sound (20-180 Hz), while others suffer from low-frequency tinnitus (perceived frequency 40-100 Hz). Physical sound at frequencies below 20 Hz (infrasound) is not responsible for the annoyance or at all audible - in any of the investigated cases, and none of the complainants has extraordinary hearing sensitivity at low frequencies. For comparable cases of low-frequency noise complaints in general, it is anticipated that physical sound is responsible in a substantial part of the cases, while low-frequency tinnitus is responsible in another substantial part of the cases.
|
|
