The Experts below are selected from a list of 336 Experts worldwide ranked by ideXlab platform
Bret W. Butler - One of the best experts on this subject based on the ideXlab platform.
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wildland firefighter Safety Zones a review of past science and summary of future needs
International Journal of Wildland Fire, 2014Co-Authors: Bret W. ButlerAbstract:Current wildland firefighter Safety Zone guidelines are based on studies that assume flat terrain, radiant heating, finite flame width, constant flame temperature and high flame emissivity. Firefighter entrapments and injuries occur across a broad range of vegetation, terrain and atmospheric conditions generally when they are within two flame heights of the fire. Injury is not confined to radiant heating or flat terrain; consequently, convective heating should be considered as a potential heating mode. Current understanding of energy transport in wildland fires is briefly summarised, followed by an analysis of burn injury mechanisms within the context of wildland fire Safety Zones. Safety Zone theoretical and experimental studies are reviewed and a selection of wildland fire entrapments are examined within the context of safe separation distances from fires. Recommendations are made for future studies needed to more fully understand and define wildland firefighter Safety Zones.
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Firefighter Safety Zones: A Theoretical Model Based on Radiative Heating
International Journal of Wildland Fire, 1998Co-Authors: Bret W. Butler, Jd CohenAbstract:Quantitative information regarding Safety Zone size for wildland firefighters is limited. We present a 3-surface theoretical model that describes the net radiant energy transfer to a firefighter standing a specified distance from a fire of specified height. Model predictions compare favorably with qualitative data from entrapments on four wildfires and two previously published models. Calculations indicate that for most fires, Safety Zones must be greater than 20 m wide to ensure firefighter survival. A general rule-of-thumb derived from this work is that a Safety Zone radius must be equal to or greater than 4 times the maximum flame height.
Zvi Karni - One of the best experts on this subject based on the ideXlab platform.
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A Graphical Method for the Estimation of Radiation Hazards from a Crowded Multiple Antenna Site
Environmentalist, 2005Co-Authors: Moshe Z. Netzer, Avi Shechter, Zvi KarniAbstract:The major objective of the design of safe crowded transmitting antenna sites is not only to determine a safe Zone around each individual antenna; rather, to establish Safety areas at the antenna site itself, as well as, at the neighboring areas. The requirement is to ascertain the Safety regions by considering the following parameters at each Test Point (TP) (or area segment): the contribution of N co-located radiating antennas to the total radiation incident at the TP, the radiation pattern of each antenna, the near/far field region of each antenna, and most importantly, the different Permissible Exposure Limits (PELs) associated with each operating frequency at the antenna site. Implementation of all the above-mentioned aspects in a suitable computer requires resources that only expert knowledgeable organizations possess. The graphically aided tool presented in this paper facilitates the calculation of a “Safety Zone” for RADHAZ around a crowded antenna site from the knowledge of the “Safety ranges” which correspond to the individual transmitting antennas comprising it.
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A graphical method for the estimation of radiation hazards from a crowded multiple antenna site
2004 23rd IEEE Convention of Electrical and Electronics Engineers in Israel, 1Co-Authors: Moshe Netzer, Avi Shechter, Zvi KarniAbstract:The major objective of the design of safe crowded transmitting antenna sites is not only to determine a safe Zone around each individual antenna, but also to establish Safety areas, both at the antenna site itself and at neighboring areas. The requirement is to ascertain the Safety regions by considering the following parameters at each test point (TP) (or area segment): the contribution of N colocated radiating antennas to the total radiation incident at the TP; the radiation pattern of each antenna; the near/far field region of each antenna; most importantly, the different permissible exposure limits (PELs) associated with each operating frequency at the antenna site. Implementation of all the above-mentioned aspects in a suitable computer requires resources that only expert knowledgeable organizations possess. The graphically aided tool presented facilitates the calculation of a "Safety Zone" for RADHAZ around a crowded antenna site from the knowledge of the "Safety ranges" which correspond to the individual transmitting antennas comprising it.
Panagiotis D. Christofides - One of the best experts on this subject based on the ideXlab platform.
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process operational Safety using model predictive control based on a process safeness index
Computers & Chemical Engineering, 2017Co-Authors: Fahad Albalawi, Helen Durand, Panagiotis D. ChristofidesAbstract:Abstract It has been repeatedly suggested that the common cause-and-effect approach to evaluating process Safety has deficiencies that could be addressed by a systems engineering perspective. A systems approach should consider Safety as a system-wide property and thus would be required to integrate all aspects of the process involved with monitoring or manipulating the process dynamics, including the control, alarm, and emergency shut-down systems while operating them independently for redundancy. In this work, we propose initial steps in the first systems Safety approach that coordinates the control and Safety systems through a common metric (a Safeness Index) and develop a controller formulation that incorporates this index. Specifically, this work presents an economic model predictive control (EMPC) scheme that utilizes a Safeness Index function as a hard constraint to define a safe region of operation termed the Safety Zone. Under the proposed EMPC design, the closed-loop state of a nonlinear process is guaranteed to enter the Safety Zone in finite time in the presence of uncertainty while maximizing a stage cost that reflects the economics of the process. Closed-loop stability is established for a nonlinear process under the proposed implementation strategy.
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Process safeness index: Its definition and use in economic model predictive control to ensure process operational Safety
2017 American Control Conference (ACC), 2017Co-Authors: Fahad Albalawi, Helen Durand, Anas Alanqar, Panagiotis D. ChristofidesAbstract:In this work, we propose initial steps in the first systems Safety approach that coordinates the control and Safety systems through a common metric (a Safeness Index) and develop a controller formulation that incorporates this index. Specifically, this work presents an economic model predictive control (EMPC) scheme that utilizes a Safeness Index function as a hard constraint to define a safe region of operation termed the Safety Zone. Under the proposed EMPC, the closed-loop state of a nonlinear process can be guaranteed to enter the Safety Zone in finite time while maximizing the process economics. The proposed design is demonstrated using a chemical process example.
Hélio Pereira Lopes - One of the best experts on this subject based on the ideXlab platform.
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the internal anatomy of danger Zone of mandibular molars a cone beam computed tomography study
Journal of Conservative Dentistry, 2018Co-Authors: Sheila Silva Leite Pinto, Renata Ximenes Lins, Michelle Da Silveira Guimarães, Barbara Alves Da Fonseca, Antonio Ermelindo Radetic, Ália Regina Neves De Paula Porto, Marilia F Marcelianoalves, Hélio Pereira LopesAbstract:Aim: The aim of this study was the assessment of the anatomical thickness of danger Zone in the cervical third of mesial canals of mandibular molars. Materials and Methods: Fifty mandibular molars were selected and scanned with cone-beam computed tomography. Data were compared using a length tool provided by scanner software. The measured areas were the mesial and distal walls of the cervical third of the mesial roots, which correspond to the Safety and danger Zones, respectively. In addition, dentin thickness at the furcation was evaluated. Results: Dentin thicknesses of the Safety Zone were higher than in the danger Zone in all teeth examined. The thinnest dentin of the Safety Zone was found at a point located 4 mm below the canal orifice, with a mean value of 1.03 mm; conversely, in the danger Zone, the thinnest point was located 3 mm below the orifice, with a mean value of 0.81 mm. As for the distance from the pulp chamber floor to the furcation, the average value was 2.23 mm. Conclusion: These results show that mean thicknesses at the danger Zone of mandibular molar mesial roots were <1.0 mm. These data reinforce the importance of understanding anatomy and the need for conservative preparations when assessing and instrumenting these root canals.
Fahad Albalawi - One of the best experts on this subject based on the ideXlab platform.
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process operational Safety using model predictive control based on a process safeness index
Computers & Chemical Engineering, 2017Co-Authors: Fahad Albalawi, Helen Durand, Panagiotis D. ChristofidesAbstract:Abstract It has been repeatedly suggested that the common cause-and-effect approach to evaluating process Safety has deficiencies that could be addressed by a systems engineering perspective. A systems approach should consider Safety as a system-wide property and thus would be required to integrate all aspects of the process involved with monitoring or manipulating the process dynamics, including the control, alarm, and emergency shut-down systems while operating them independently for redundancy. In this work, we propose initial steps in the first systems Safety approach that coordinates the control and Safety systems through a common metric (a Safeness Index) and develop a controller formulation that incorporates this index. Specifically, this work presents an economic model predictive control (EMPC) scheme that utilizes a Safeness Index function as a hard constraint to define a safe region of operation termed the Safety Zone. Under the proposed EMPC design, the closed-loop state of a nonlinear process is guaranteed to enter the Safety Zone in finite time in the presence of uncertainty while maximizing a stage cost that reflects the economics of the process. Closed-loop stability is established for a nonlinear process under the proposed implementation strategy.
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Process safeness index: Its definition and use in economic model predictive control to ensure process operational Safety
2017 American Control Conference (ACC), 2017Co-Authors: Fahad Albalawi, Helen Durand, Anas Alanqar, Panagiotis D. ChristofidesAbstract:In this work, we propose initial steps in the first systems Safety approach that coordinates the control and Safety systems through a common metric (a Safeness Index) and develop a controller formulation that incorporates this index. Specifically, this work presents an economic model predictive control (EMPC) scheme that utilizes a Safeness Index function as a hard constraint to define a safe region of operation termed the Safety Zone. Under the proposed EMPC, the closed-loop state of a nonlinear process can be guaranteed to enter the Safety Zone in finite time while maximizing the process economics. The proposed design is demonstrated using a chemical process example.
