Atomistic potential for graphene and other sp2^2 carbon systems

We introduce a torsional force field for sp$^2$ carbon to augment an in-plane atomistic potential of a previous work (Kalosakas et al, J. Appl. Phys. {\bf 113}, 134307 (2013)) so that it is applicable to out-of-plane deformations of graphene and related carbon materials. The introduced force field is fit to reproduce DFT calculation data of appropriately chosen structures. The aim is to create a force field that is as simple as possible so it can be efficient for large scale atomistic simulations of various sp$^2$ carbon structures without significant loss of accuracy. We show that the complete proposed potential reproduces characteristic properties of fullerenes and carbon nanotubes. In addition, it reproduces very accurately the out-of-plane ZA and ZO modes of graphene's phonon dispersion as well as all phonons with frequencies up to 1000~cm$^{-1}$.Comment: 9 pages, 6 figure

Approaches for preventing and mitigating accidental gaseous chemical releases

This paper presents a review of approaches to prevent and mitigate accidental releases of toxic and flammable gases. The prevention options are related to: choosing safer processes and materials, preventing initiating events, preventing or minimizing releases, and preventing human exposures. the mitigation options include: secondary confinement, de-inventory, vapor barriers, and water sprays/monitors. Guidelines for the design and operation of effective post-release mitigation systems are also presented

Mitigation of unconfined releases of hazardous gases via liquid spraying

The capability of water sprays in mitigating clouds of hydrofluoric acid (HF) has been demonstrated in the large-scale field experiments of Goldfish and Hawk, which took place at the DOE Nevada Test Site. The effectiveness of water sprays and fire water monitors to remove HF from vapor plume, has also been studied theoretically using the model HGSPRAY5 with the near-field and far-field dispersion described by the HGSYSTEM models. This paper presents options to select and evaluate liquid spraying systems, based on the industry experience and mathematical modeling

Mitigation options for accidental releases of hazardous gases

The objective of this paper is to review and compare technologies available for mitigation of unconfined releases of toxic and flammable gases. These technologies include: secondary confinement, deinventory, vapor barriers, foam spraying, and water sprays/monitors. Guidelines for the design and/or operation of effective post-release mitigation systems and case studies involving actual industrial mitigation systems are also presented

The OSHA and EPA programs on preventing chemical accidents and potential applications in the photovoltaic industry

OSHA issued in 1992, the Process Safety Management (PSM) of Highly Hazardous Substances. This rule requires owners/operators of facilities that handle hazardous chemicals in quantities greater than the listed thresholds to establish all the elements of a PSM. EPA has issued in June 1996, the rules for a Risk Management Program which also refers to specific substances and threshold quantities. These rules are applicable to all the facilities that use or store any of 139 regulated substances at quantities ranging from 100 lb to 10,000 lb. The RMP rule covers off-site hazards, while the OSHA Process Safety Management (PSM) rule covers worker safety issues within the plant boundary. Some of the listed substances may be found in photovoltaic manufacturing facilities. This brief report presents the basic elements of these two rules and discusses their potential applicability in the photovoltaic industry