Regional Evacuation Modeling System (REMS): A decision support system for emergency area evacuations

In this paper we present a decision support system being developed at the University of Florida. The system is a PC-based software package that is capable of testing different emergency scenarios due to hurricanes, chemical accidents or nuclear accidents. The underlying models are optimization models based on a regional transportation network. One of the most significant aspects of the software is its ability to handle time dimension of the problem explicitly. It is this aspect of REMS that makes incorporation at any time of road blockages due to the presence of extremely hazardous substances or inundation of roads due to accidents or flooding possible in evacuation scenarios tested. The software has the ability to animate the evacuation process in time and display the flow of traffic on the links of the transportation network in a time-lapsed manner with color codes. Additionally REMS is also capable to animate the progress of the plume exposure pathway of an extremely hazardous substances as it evolves in time onto the evacuation network and to display the dynamic vehicle flow in time simultaneously.     

An engineering economy expression analyzer

Students and practitioners of engineering economy are faced with the unenviable task of evaluating engineering economy expressions. If the example expression: 1000 ^* (P/F,10,5) − 500 ^* (P/F,6,20) + 100 ^* (P/A,8,20) were solved manually, it would require three table look-ups to determine the values of the cash flow factors.

This paper discusses the automation of engineering economy expression analysis. A public domain program has been developed that solves engineering economy expressions. The above expression can be entered into the program exactly as written, and the computer will respond with the evaluated result. The program also has an integral editor and the ability to solve for unknowns such as interest rates.     

Correlation Between Potentiodynamic Polarization Behaviors of Transient Liquid Phase Bonded 2205 Duplex Stainless Steel and the Bonding Constituents

In order to precisely evaluate the contribution of each bonding constituent to the pitting corrosion resistance of transient liquid phase (TLP) bonded 2205 duplex stainless steel (DSS), we have undertaken potentiodynamic polarization (PDP) and microstructural analytic measurements all across the TLP bonded area. The PDP results show that the pitting corrosion resistance of TLP bonded specimens is significantly affected by the presence of certain bonding constituents across the TLP bonded area. Electron microscopy analysis indicates that the formation of complex (Fe,Ni,Cr,Mo)₃P phosphide in the bonding zone (BZ) before the completion of isothermal solidification (IS) as well as the formation of P-rich sigma phase in the diffusion-affected zone (DAZ) following the completion of the IS provides the most preferential sites for the occurrence of pitting corrosion. The PDP results also confirm that the pitting potentials (E_pit) of the TLP bonded specimen before and after IS completion are, respectively, closer to the E_pit of the BZ and the E_pit of the DAZ rather than to those of other TLP BZs.

     

Relationship Between Methanol Permeability and Structure of Different Radiation‐Grafted Membranes

Styrene grafted and sulfonated poly(vinylidene fluoride) and poly(vinylidene fluoride‐co‐hexafluoropropylene) films are candidates as electrolytes in direct methanol fuel cells. Their behaviour in water, 1 and 3 mol dm^–3 aqueous methanol, and pure methanol were studied. According to SAXS results, water and methanol‐water solutions have similar effects on the membranes, i.e., the lamellar period increases and the ionic domains enlarge. Furthermore, differences in the ionic domain structures in pure methanol and water were observed. These structural changes together with dissimilar liquid uptakes in water and in methanol are reflected as changes in the conductivities. An increase in the SAXS intensity and changes in the Bragg distance of the ionic peak were observed in methanol compared to aqueous solutions. This may be related to the hydrophobicity of the CH₃ group on methanol. Dissimilarities in methanol permeability through the radiation‐grafted membrane can be related to structural differences in membranes observed with SAXS. Permeabilities were observed to be lower for the radiation‐grafted membranes compared to Nafion® 115, which compensates for the higher area resistance of the experimental membranes and thus improves their performance in a fuel cell.     

Dynamic and Postdynamic Recrystallization Behavior of GWZ Magnesium Alloy Under Double-Hit Hot Compression

Herein, dynamic and postdynamic recrystallization behaviors of GWZ magnesium are investigated. Toward this end, the single-hit and double-hit hot compression tests are conducted under strain rate of 0.001 s⁻¹ at 400 °C. The prestrains of 0.1 and 0.5 are considered to investigate the effect of interpass time (5–300 s) on the compressive strength level. At the low strain level of 0.1, the contribution of Hall–Petch effect is considerable due to the occurrence of static recrystallization. In addition, the rare earth texture component is eliminated during interpass annealing. This causes increasing the strength of the material during second pass of hot compression. In contrast, at higher imposed strain, the strength level decreases with increasing the interpass time of annealing. The high amount of strain is completely consumed and the remaining stored energy is not high enough to trigger the occurrence of static recrystallization. The occurrence of metadynamic recrystallization and subsequent growth are characterized. In addition, the texture does not change in respect of the intensity or numbers/types of components. Accordingly, the observed decreasing trend of the strength is justified relying on the occurrence grain growth.