China
Africa
Explore chapters and articles related to this topic
Laser Sources Based on Semiconductor Media and Nonlinear Optic Phenomena
Published in Helmut H. Telle, Ángel González Ureña, Laser Spectroscopy and Laser Imaging, 2018
Helmut H. Telle, Ángel González Ureña
It is next to impossible to lump all laser sources together as one unique group with common safety limits; however, it is possible to group certain laser sources, and their use, into “classes” according to their MPE and AEL values. Within the regulatory framework for laser safety, lasers are assigned into four broad hazard classes (1, 2, 3, and 4), depending on their potential to cause biological damage, in particular to the eye. Brief descriptions and properties for these, and specific subclasses, are collated in Table 5.2. It should be noted that laser users may still find old (prior to 2007) classification labelling in Roman numerals (classes I to IV), although these should no longer be used; cross-correlation to these classes is included in the aforementioned laser standard documents.
Occupational Health and Safety
Published in Terry Jacobs, Andrew A. Signore, Good Design Practices for GMP Pharmaceutical Facilities, 2016
In general, optical radiation can cause adverse health effects to the eyes and skin. Lasers may be used in analytical laboratories for particle sizing or in pharmaceutical packaging areas in which bar coding is used. Various consensus organizations, including the American National Standards Institute (ANSI) (ANSI Z136.1, “Safe Use of Lasers,” 2000), have established guidelines for the operation of lasers and the design of facilities in which lasers are operated. International laser safety standards include IEC 608 25-1 on the safety of laser products. Lasers are classified according to their output power. In general, lasers used for particle sizing and bar coding are low powered, with output powers of less than 5 mW. The use of these lasers requires standard precautions to be taken to limit the potential for exposure to laser light. The use of higher-powered lasers with output powers of more than 5 mW requires more rigorous controls. Facility design considerations should be taken into account, including providing nonreflective surface finishing in areas in which lasers will be used to minimize reflection and scattering of laser light, and locating laser equipment so that it is limited to responsible personnel only and potential incidental exposure to bystanders is minimized.
The New Maximum Permissible Exposure
Published in Barat Ken, Laser Safety Tools and Training, 2017
At the core of all laser-safety guidelines is the concept of maximum permissible exposure (MPE), defined as the level of laser radiation to which an unprotected person may be exposed without adverse biological changes in the eye or skin (ANSI, 2007; ICNIRP, 2000; IEC, 2007). Although the concept of MPE is quite simple, the reality is that it is multidimensional, dependent on the wavelength and duration of the exposure and modulated by the presence of repetitive pulses and diffusers or optics, which might increase the size of the beam at the target tissue. The guidelines include several pages of rules, tables, charts, conditionals, and caveats for the computation of the MPE for all reasonably foreseeable laser applications.
Potential occupational hazards of additive manufacturing
Published in Journal of Occupational and Environmental Hygiene, 2019
Gary A. Roth, Charles L. Geraci, Aleksandr Stefaniak, Vladimir Murashov, John Howard
For many potential hazards of AM, appropriate and generally accepted practices and controls already exist. Control of particulate emissions (including ultrafine) has been well validated using local exhaust ventilation and HEPA filtration.[46] Consensus standards on laser safety such as ANSI Z136 will remain applicable in AM systems.[47] Use of these and other existing guidance, methods, and standards should be considered in the context of initially addressing potential hazards. Challenges are more likely to arise in the context of novel and partially novel hazards. Addressing such concerns will require a holistic approach, considering the hazards both individually and in tandem.
Flexible blue phase liquid crystal film with high stability based on polymerized liquid crystals
Published in Liquid Crystals, 2020
Xiaowan Xu, Yanjun Liu, Dan Luo
Blue phase liquid crystal can be fabricated to film through adding high percentage of reactive mesogen into chiral dopant doped liquid crystals, bringing the advantages of better flexibility and broadened stable temperature range for wearable photonic device and sensor applications, where a complicated multi-step method called ‘wash-out’and ‘refill’ process is usually applied [30–37]. In addition, the existence of liquid crystal in blue phase liquid crystal films (BPLCF) is vulnerable to the external circumstance such as temperature and mechanical stress. It is a drawback in applications such as static colourful display, and laser safety filter, where the premier requirement is stability instead of tenability.
Radiation Protection at Petawatt Laser-Driven Accelerator Facilities: The ELI Beamlines Case
Published in Nuclear Science and Engineering, 2023
Anna Cimmino, Veronika Olšovcová, Roberto Versaci, Dávid Horváth, Benoit Lefebvre, Andrea Tsinganis, Vojtěch Stránský, Roman Truneček, Zuzana Trunečková
Finally, clean room attire and laser-safety goggles limit movement and visibility, extending the time needed for any intervention (see Fig. 7). This limitation must be factored in when planning activities in radiation areas. On the other hand, the compulsory protective clothing (including gloves) reduces the risk of skin contamination when handling activated material.