Audible signal

In the startup of a reactor, it is necessary to have a source of neutrons other than those from fission. Otherwise, it might be possible for the critical condition to be reached without any visual or audible signal. Two types of sources are used to supply neutrons. The first, appHcable when fuel is fresh, is califomium-252 [13981-174-Jwhich undergoes fission spontaneously, emitting on average three neutrons, and has a half-life of 2.6 yr. The second, which is effective during operation, is a capsule of antimony and beryUium. Antimony-123 [14119-16-5] is continually made radioactive by neutron... 

The malfunction audible signal should be capable of being silenced after operation of an acknowledgment "trouble alarm silence" switch. The visual trouble signal should remain illuminated. 

Different laboratories use different criteria for determining whether a drop-test resulted in an explosion ( go ) or failure ( no-go ). In many test facilities any visual observation of smoke, flash or flame, or any crackle, pop or bang detected by the operator is taken to signify a go result. Sometimes sound-meters are used to detect the audible signals of a drop test. In still more elaborate tests, the volume of gas, produced by a go result, is measured. In general, for sensitive explosives like PETN, distinguishing between go ... 

The most important keyword is masking . It describes the effect by which a fainter, but distinctly audible signal (the maskee) becomes inaudible when a correspondingly louder signal (the masker) occurs simultaneously. Masking depends both on the spectral composition of both the masker and the maskee as well as on their variations with time. 

For the STFT case, the bandwidth of the filter-bank is inversely proportional to the duration of the short-time frame and it is shown in [Cappe and Laroche, 1995], using standard results concerning the simultaneous frequency masking phenomenon, that the processing can suppress audible signal components (ie. components that were not masked by the additive noise) if the short-time duration is well below 40 ms. 

To eollect vapours the user samples in and around an area where explosives are suspeeted. To eollect particles, the user wipes the surface of suspect articles with gloves and transfers the sample onto a metal sample screen. The sample screen (Figure 2) is then inserted into the E-3500 for analysis. The analysis is usually completed within 10 seconds and the results displayed on the LCD (liquid crystal display). An alarm is indicated hy a red light, audible signal, and a value displayed on the LCD. 

Power Audible signaling devices Beit 1 Butier... 

The manual cleaning of sludges and deposits in the bottom of stills and storage tanks which have contained low flash point solvents is particularly hazardous if low level ventilation is not provided. Test equipment placed at ground level and giving an audible signal if the danger concentration is exceeded is very desirable. 

Test requirements are specified. It is recommended that the response of each channel to radiation be determined at least monthly and that the entire system be tested periodically. Audible signal generators ati to be tested at least once every three months, with a determination that the signals be audible above background for all areas that are to be evac-... 

Audible signal means a signal made by a distinct sound or series of sounds. Examples include, but are not limited to, sounds made by a bell, horn, or whistle. 

Display is perhaps a misnomer because information can also be passed on by non-visual stimuli, such as different types of audible signals. 

One very sueeessful measure we took was to run part of the software system test suite in the same environment as its expected final use. Hence, it proved to be an intelligent idea since we discovered many defects we would not have discovered until the instrument would have been in the field. This was because another factor to consider is the environment where the device is used, e.g. if the user works in an extremely noisy environment, then the effect of risk mitigations based on audible signals and alarms may be altered or invalidated. The same applies to visual alarms when the user is operating with other devices at the same time and not paying attention to the computer screen. Note also, as eommented before, that users may interfere with the expected use. Indeed, the noisiest alarm that mitigates a safety eritieal situation may become useless if the user turns off the computer... 

An on/off button, a light button which illuminates the display and acts as a battery check (BATT will appear in the lower left corner of the display, if not, replace the battery), a speaker button activates or deactivates an audible signal, and a Range button switches between the low and high ranges. 

ABSTRACT The purpose of this work is to expand the knowledge of contexts surrounding accidents in occupational situations. Particularly, a theoretical study concerning causes of accidents is conducted. It allowed to differentiate the most often considered aspects such as human and technical. In this paper a special attention was paid to assuring safety by process control in which the contributor is human and his/ her response to system alarms. The study, undertaken in a simulation situation, concerned human reaction to visual and audible signals which had to reflect alarms for process control. The results of the study showed that the visual indicators were more often correctly perceived than that of auditory signal. 

In this paper, theories of accident causation are presented and process safety issues are highlighted. The aspects of alarms are also described as they constitute the basis for the practical investigation. The aim of the simulation study was to assess time and correctness of human reaction to visual and audible signals, which can be used for process monitoring. The final part of the paper summarizes... 

Recent industrial disasters have highlighted the need for improved safety and an increasing number of industrial quality and reliability systems. Therefore, alarms signalisation is frequently performed via display terminals where information for operators is presented in a variety of formats. In this paper a particular attention is paid to displays for alarm presentation such are visual and audible signals. The results of the present study revealed that the participants can react faster and more correctly to visual signals than audible one. 

An exclusive alert Is given to staff (this may be coded or a discreet visual or audible signal or message)... 

In general alarm sounders giving audible signals must be appropriate to the circumstances and must not be able to be confused with any other alarm. 

Visual alarm systems - visual alarm systems (beacons) are used to supplement audible warning signals in situations where an audible system is likely to be ineffective, for example where the ambient noise levels in the building would make it difficult to hear an audible signal. Beacons must be provided where ambient noise levels exceed 90 dB(A), or in areas where hearing protection is worn or people with hearing impairments may be present. 

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