1,720,990 research outputs found
Review of necessary risk assessment equipment for prevention of hand-arm vibration syndrome
No full textThe EU Directive 2002/44/EC1 of the Physical Agent Directive (Vibration) defined three things to employers. For preventing hand-arm vibration syndrome (HAVS) among workers, employers must take the following measures: ① choose appropriate working equipment producing the least possible vibration, ②assess probable magnitude of the vibration, based on the daily exposure value normalized to an eight-hour reference period A(8), and ③if possible, measure the levels of mechanical vibration to which workers are exposed at the worksite, to assess whether the health and safety risk of each worker is ensured. For preventing HAVS, the A (8) is considering the introduction of risk assessment as following steps
Hand arm vibration mitigation at workplace: a review of vibrartion perception thresholds shift
No full textThe prolonged use of hand-held tools workers may develop Hand-Arm Vibration Syndrome (HAVS), which affects the vascular, neurological, and musculoskeletal systems at the hands1. Vascular disease results in finger blanching (Raynaud’s phenomenon) and finger coldness. Neurological disease results in pain, dysesthesia, paraesthesia, tingling and numbness. Musculoskeletal disease results in pain, loss of muscle power and manual dexterity, and deformity of bones and joints. A shift in the Vibrotactile Perception Threshold (VPT) has historically been used in a number of countries for the diagnosis of HAVS, especially the diagnosis of neurological injuries2. This paper is to review the existing VPT research, identify the relationship between the measurement of vibration dose value and VPT measurements
Study on effectiveness of social distancing equipment at construction sites
No full textCurrent methods for control social distance at worksites is using marker, tape, or barrier to label the distance of 2 m. However, at the practical worksite, due to the complexity and the nature of the tasks, it was difficult for the construction workers themselves who need to move constantly while completing their tasks to maintain the social distance. Furthermore, the variation in contacting time between workers within 2 m is still unknown and the importance for using monitoring devices to provide additional awareness need to be addressed. The purpose of this study is to investigate the effectiveness of the hand wear device with the Social Distancing function in maintaining the 2m distance and monitoring the contacting time (times for workers within 2m distance). The results also suggested that the total contacting time and average contacting time per worker with Social Distancing Equipment is decreased when compared with traditional social distancing control methods. The hand wear monitoring devices could be used as an effectiveness preventive measure against infectious diseases of workers at worksites
Necessity and Considerations for On-Body Vibration Measurement Equipment
No full textThe palmar surface (on tool surface) has been defined in ISO 5349-1 as a value of the amount of vibration transmitting to the hand and arm from on-body vibration magnitude. They showed the concept of on-body vibration measurement based on the relationship between the temporary threshold shift (TTS) of the vibrotactile perception threshold (VPT) and the on-body vibration measurement values. However, they did not show that the effectiveness of ISO 5349-1 Annex D for various factors transmitting to the hand was unknown. Therefore, the purpose of this paper is to clarify the new considerations of on-body vibration measurement equipment and to demonstrate the necessity of on-body measurement equipment
Vibrotactile temporary threshold shifts induced by hand-transmitted vibration during underwater work
No full textThe purpose of this paper is to clarify the temporary threshold shifts (TTS) of fingertip vibratory sensation produced by hand-transmitted vibration in an underwater work environment. The hand-transmitted vibration was applied with a pneumatic tool to the right hand of four experienced male SCUBA divers. The threshold of 125 Hz vibratory sensation was measured at the tip of the right forefinger before and after vibration exposure in the atmosphere and underwater. Vibration exposure at a 4 m depth produced greater TTS than in the atmosphere. The recovery time of TTS after vibration exposure in an underwater were affected by the underwater pressure.</p
Motion sickness in automated vehicles: principal research questions and the need for common protocols
Get PDFMotion sickness in automated vehicles (AVs) represents a key Human Factors concern that will negatively impact the passenger experience and, ultimately, public acceptance. Minimizing or avoiding motion sickness altogether, therefore, becomes a strategic design goal. In this articlewe propose principal research questions that need to be addressed as part of a concerted effort to understand the causative factors of motion sickness and the need to develop and apply common protocols to accelerate knowledge and subsequent innovation in this field. With the ultimate goal to provide guidelines to inform the design of future vehicles, the International Organization for Standardization standard (ISO) 2631-1 (1997) is taken as the starting point. The current standard provides estimates of the likelihood of motion sickness as a function of vertical motion input only. However, in the context of AVs, and in particular in the light of anticipated non-driving-related activities in such vehicles, the current standard is of limited use: The model has not been validated for horizontal and rotational motions or any potential multi-axes interactions; The standard was derived on the basis of the percentage of passengers reaching the point of emesis while less severe levels of motion sickness are of greater interest and may show a different relationship between the frequency and acceleration; Modulating factors that are able to regulate, adjust, or adapt sickness levels are not included, in particular vision and the associated concept of anticipation, passenger orientation, and reclination angles. Finally, the accumulation of motion sickness knowledge in this field is severely hampered by the absence of consistent study protocols. We here propose the identification and development of appropriate vibration measurements and motion sickness assessment and evaluation methods
Recent Development of Ultrasonography in Urologic Field
No full text東京女子医科大学学会第47回総会 昭和56年9月26日 東京女子医科大学本部講
A Method Of Evaluating Vehicle Seat Vibration With Consideration Of Subjective Judgment - Introduction; Proceedings Of The First American Conference On Human Vibration
No full textVibration magnitude and frequency of the z-axis vehicle seat are time-variant, which are influenced by not only vehicle vibration characteristics themselves but also road surfaces, speeds and the human body. There is little in the current reporting about evaluating and analyzing automobile seat vibration that focuses on the time-variant. Yaguchi et al.1 has proposed a method to evaluate automobile seat vibration that is based on judgments using a subjective mental state. Their method focuses on the time-variant magnitude of the peak frequency on a power spectrum density. However, their method has no consideration of all the frequency contents of the discomfort, nor comparison between different peak frequency vibrations. Suzuki2 has emphasized that the vehicle vibration should be judged by a series of vibration stimuli to evaluate, because the vehicle vibration is time-variant, which isn\u2019t a matter of the relationship between a single vibration stimulus and a subjective response. He clarified that the human sensation to the vehicle vibration discomfort changes every moment showing the relationship between the frequency-weighted r.m.s. acceleration calculated every 5 seconds and the category judgment to vehicle vibration discomfort every 5 seconds. However, his study doesn\u2019t show what parameter connects to the subjective final judgment to vehicle vibration. Therefore, we applied the method similar to ISO100563 considering the time-variant to the vehicle seat z-axis vibration evaluation. The new method for the vehicle seat vibration considering the time-variant was examined on the hypothesis that the final subjective evaluation must be conducted from the judgment summarizing a series of vibration stimuli. Methods The vibration bench system, which reproduces the movement of a vehicle floor, was used for the experiment with the single-axis (vertical direction) four-post road simulator system, which is usually used for a car, as shown in Fig.1. The experiment was done on the right side of the vibration bench using the floor vibration which was 5.5 minutes, 0.822 m/sec2 (Wk) over the range 0.5-20Hz with 4 male subjects (age ave21.5, SD0.5, weight ave75kg, SD7.91kg, height ave166.8cm, SD5.2cm) and 4 suspension seats. As Fig.2 shows, subjects evaluated the degree of discomfort every 5 seconds to each seat vibration measuring the seat z-axis vibration acceleration. [
Multi-Axis Hand-Arm Vibration Testing & Simulation At The National Institute Of Industrial Health, Kawasaki, Japan - Introduction; Proceedings Of The First American Conference On Human Vibration
No full textHand-Arm Vibration Syndrome (HAVS) was identified as early as 1918 in Bedford, Indiana in the U.S. Since then much research work has been done around the world in the areas of medical, epidemiological, engineering and legal aspects of HAVS. In Japan, much of the pioneering work in this field has been performed by Dr. Setsuo Maeda and his staff at the National Institute of Industrial Health (NIIH) in Kawasaki. Most recently, reports of work done by this group and by Dr. Ren Dong1 of NIOSH in the U.S., as well as many other suppliers and Japanese practitioners were presented at the 13th Japan Group Meeting on Human Response to Vibration held in Osaka2 during August 3-5, 2005. [
Establishment Of An Experimental System For Measring Biodynamic Response Of Hand-Arm - Introduction; Proceedings Of The First American Conference On Human Vibration
No full textThis paper addresses establishment of an experimental system for measuring biodynamic response (BR) of hand-arm system at the NIIH in Japan. BR measurement system at the NIIH is nearly equivalent to NIOSH installed system. The feasibility of the system is examined through the apparent mass (AM) measurement of the empty handle and a set of calibration masses. Apparatus The grip force was measured by using the handle shown in Fig. 1. The handle has two force sensors (KISTLER, 9212) and one accelerometer (PCB, 356A12). A low-pass filter with 5 Hz cut-off frequency was used to the grip force from measured force signal. Figure 2 shows BR measurement system in this study. The push or pull force at the handle was measured by using the force plate (KISTLER, 9286AA). The grip force and the push / pull force were displayed on a monitor. The shaker (IMV, VE-100S) is used to vibrate the hand-arm system along the forearm axis (Zh direction) (ISO 10068, 1998; ISO 5349-1, 2001). In most situations force actions for operating tools are expressed by grip, push, pull and combined these actions. These actions can be simulated in the test system. AM was obtained by performing H1 estimator in the PULSETM system (B&K, 3109) and it is denoted at the one-third octave band center frequencies. [ ] Methods In order to investigate the reliability of the system, AM measurement of the handle was performed. It is assumed that the handle is rigid in the upper limit of adoptive frequency range in this study. This assumption is validated in AM measurement of the empty handle. A pseudo-random vibration in the frequency range of 10 to 1,250 Hz was used and its amplitude is 1.0 (m/s2)2/Hz with a flat power spectral density (PSD) in the experiment. Measured AM includes the mass effect of the measuring cap in a subject experiment. Compensated apparent mass AMc(?) is obtained by Eq. (1) 1-2
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