bluuebunny/crossref_metadata_2025_split huggingface dataset:
Health, safety and environmental protection: A new audit program
Authors: Scheid Daniel C. 
Published: June 2004

AbstractIn September, 1985, Union Carbide established a new, comprehensive corporate‐level audit program. The development of this program included careful consideration and incorporation of current and emerging practices in the field of health, safety, product responsibility and environmental auditing. Union Carbide's efforts in this area are but one element of its overall health, safety and environmental management system.
Estimation of catastrophic quantities of toxic chemicals by atmospheric dispersion modeling
Authors: Costanza Peter A. , Hagen George L. , Kalagnanam Ramesh S. , Komosinsky Paul J. 
Published: June 2004

AbstractIn response to the Bhopal disaster and several repeated chemical releases (even though of less dangerous magnitude) in New Jersey, the state of New Jersey passed a bill on January 8, 1986, which is aimed at the prevention of such catastrophic releases in the state. This bill is officially referred to as the Toxic Catastrophe Prevention Act (TCPA).The TCPA identified eleven specific Extraordinarily Hazardous Substances (EHS). Table 1 lists these eleven EHS identified in the Act and their reportable quantities. The TCPA aims at the prevention of the release of these EHS into the environment. The Legislature did not provide the basis and background of the development of the reportable quantities of these eleven EHS.The TCPA mandates that the New Jersey Department of Environmental Protection (NJDEP) shall expand the list of these EHS and shall “… correlate the substances with the quantities required to produce the potentially catastrophic circumstances.”
The advantages and limitations of adiabatic Dewar calorimetry in chemical hazard testing
Authors: Rogers Richard L. 
Published: June 2004

AbstractAdiabatic Dewar Calorimeters can be used to measure the temperature time curve of self heating and the induction time of thermal explosions. The important experimental parameters which allow the data to be determined under conditions which directly simulate plant situations are described. The advantages and limitations of the technique are discussed, showing where it can be used to define the process conditions under which uncontrolled reaction could be initiated and to quantify the consequences of such reactions.
Deflagration suppression of high Kst dusts
Authors: Senecal Joseph A. 
Published: June 2004

AbstractDeflagration suppression is one of several means of explosion protection for process volumes. This paper presents a discussion of some of the variables which influence the final pressure obtained upon suppression of a process deflagration. In particular the discussion focuses on suppression of the deflagrations of fast burning dusts, i.e. dusts with high Kst values. The discussion is amplified using recently obtained data from deflagration and suppression tests on three flammable dusts representing the St‐2 and St‐3 deflagration classes. It is shown that the relationship between post‐suppression pressure and Kst value is not always as expected. The underlying reason for this result relates to differences in the burning characteristics of the subject dusts in the relevant stages of the deflagration.
Assessing a runaway of a Grignard reaction
Authors: Jones M. C. 
Published: June 2004

AbstractThe venting and control strategies of a Magnesium Grignard formation reaction were assessed by theoretical predictions of the exotherm and the reaction rate, by simple laboratory measurements of the self heat rate, and by Leung's simplified equations and SAFIRE evaluations, based on DIERS methods. SAFIRE computations showed that the 150 mm dia vent was capable of keeping the reactor pressure below its maximum (MAWP) of 860 kPa for the worst‐case exotherm.The response to this evidence was to increase safety protection in the automatic control strategy, following a quantified fault tree analysis of the worst‐case runaway scenario.
Plant modifications: Maintain your mechanical integrity
Authors: Ramsay Curtis W. 
Published: June 2004

AbstractUpon initial review of the proposed subject, Plant Modifications and Mechanical Integrity, there is a bit of a disappointment, a lot of the subject matter can easily be placed under the heading “Common Sense.” However, after reviewing successes and failures in this area one finds that common sense may not be as common as one would like. While the successes are much more frequent than the failures, the failures tend to overwhelm the impact of the successes.
Application of twin screw extruders for reactive processing
Authors: Jackson Steven M. , Dreiblatt Adam 
Published: June 2004

AbstractReactive extrusion has grown in a few years from a specialized technique for creating experimental materials to the preferred production technique for manufacture of standard polymer systems (ex. polyurethanes) and modification of these systems (ex. grafting). The complexity of the extruder system design has also grown tremendously. The ability of reactive extrusion to produce a myriad of products in a single piece of capital equipment makes it attractive to R&D, manufacturing and financial groups.
Spontaneous fires in insulation
Authors: Britton Laurence G. 
Published: June 2004

AbstractCombustible liquids may self‐heat in porous insulation yielding smoldering or flaming combustion. In Part I the problem is reviewed and practical measures discussed. Using two‐inch cubes of insulation and a standardized procedure, Spontaneous Ignition Temperatures (SITs) ranging from 55‐184 C are reported for a series of combustible liquids. The application of a self‐heating parameter Z = (AIT)/(AIT‐FP), where AIT is autoignition temperature and FP is closed cup flash‐point (both in Celsius), is examined. The “Z” parameter gives some indication of materials that will self‐heat and those that will evaporate. For Z > 1.61 ignition occurred for all the liquids tested. Evaporation usually occurred for materials with Z < 1.35. It was found that some water‐reactive or peroxide‐forming materials can ignite where only evaporation would be predicted from Z value considerations. An important example of a water‐reactive material is ethylene oxide (EO); the importance of EO insulation fires is that under certain conditions explosive decomposition of EO contained in the equipment can be initiated.It was previously determined that ethylene oxide reacts in porous, refractory insulations forming low molecular weight polyethylene glycols. The formation rate depends on temperature and the type and condition (particularly water content) of the insulation. Unlike EO the glycols have low volatility and may accumulate over time to several times the mass of some insulations. Under certain conditions the glycols can ignite spontaneously. In Part II experiments carried out to examine this phenomenon are discussed.Where process temperatures are above the SIT (but below the AIT), cellular glass insulation will minimize the risk of insulation fires. One disadvantage, especially for thermally unstable materials such as EO, is that cellular glass has poor fire endurance properties. The use of a realistic fire endurance test to specify insulation thickness and additional measures such as stainless steel jackets are described.Alternatives to the use of cellular glass are discussed. When selecting an insulation system, it should be determined whether an insulation fire might occur and the loss potential from such an event should be evaluated.
Forestalling a serious incident: A detective story
Authors: Kaiser Mary A. 
Published: June 2004

AbstractTwo low‐level dust fires and explosions occurred in rotary dryers in one of our east Texas plants. Although there was no significant damage, the potential for safety or loss incidents initiated a concerted effort to determine the cause. The analytical and explosive hazards efforts showed an iron‐adipic compound most probably autooxidized and caused the problem.
Considerations for the safe design of processes using hydrogen peroxide and organics
Authors: Mackenzie John 
Published: June 2004

AbstractThe use of hydrogen peroxide in the chemical processing industry is increasing rapidly, both in volume and types of application. The properties of hydrogen peroxide, which make it such a useful material, can also give rise to serious hazards. This paper reviews some of the ways in which hazards may arise in organic processes using hydrogen peroxide. Some incidents are also described.
Results from the model evaluation panel
Authors: Hanna Steven , Chatwin Philip , Chikhliwaia Edul , Londergan Richard , Spicer Thomas , Weil Jeffrey 
Published: June 2004

AbstractThe purpose of this one‐day workshop on hazardous gas model evaluation was to bring together a set of experts to air the various issues on model evaluation, to draft a set of conclusions regarding the state‐of‐the‐art, and to make recommendations for future research.
Dispersion in non‐flat obstructed terrain and advanced modeling techniques
Authors: Meroney Robert N. 
Published: June 2004

AbstractAn expert panel examined the influence of complex terrain, industrial plant obstacles and thermal inhomogeneities on the dispersion of gaseous plumes or aerosols resulting from accidental releases of hazardous materials. Perturbations in transport and dispersion induced by such flow disturbances were estimated. The limitations and accuracies of current numerical and physical modeling techniques were examined. Finally, important unresolved questions concerning the estimation of transport of hazardous materials in the presence of realistic industrial building, storage and transportation environments were identified.
Using thermodynamic availability to determine the energy of explosion for compressed gases
Authors: Crowl Daniel A. 
Published: June 2004

AbstractThis paper expands on the work of Crowl [1] by using thermodynamic availability to calculate the energy of explosion for compressed gases.The results show that thermodynamic availability is a completely general approach, including effects due to chemical reaction and mechanical expansion. For the case of a non‐reactive gas, a general equation is presented to determine the energy of explosion due to mechanical expansion of the gas. The energy determined using availability is much less than the energy determined assuming an isothermal expansion and usually much more than the energy determined assuming an isentropic expansion. Since availability is a state function, the energy determined is independent of the path.
The prediction of spontaneous ignition hazards resulting from the “hot stacking” of process materials
Authors: Griffiths J. F. , Kordylewski W. 
Published: June 2004

AbstractA change in the normal routine at a factory, which produced a cellulose‐based product, necessitated taking the individual blocks of material from a hot curing process (ca. 200°C) and packing them before they had cooled to an appreciable extent. Spontaneous ignition took place in the packaged material some hours later. Considerable damage to buildings and other losses were incurred. The ambient temperature within the store was not sufficiently high to cause thermal ignition. The problem proved to be a special but not necessarily unusual case in which the onset of ignition was governed by the initial temperature of assembly of the packaged material. These circumstances have been recognized in the fibreboard manufacturing industry for example, such that US legislation requires the cooling of newly manufactured boards below a specified temperature before stacking takes place [1].We discuss the theoretical background to this type of problem, based on an adaptation of thermal ignition theory with conductive heat transport (Frank‐Kamenetskii conditions). We obtained the appropriate kinetic and thermochemical parameters for exothermic reaction in a cellulosic material in order to apply the theory. We were then able to calculate a maximum packing temperature to expedite safe but efficient storage or transport. The numerical calculations to solve the spatial and time dependent energy conservation equations by use of the finite difference method required a three dimensional grid, set up as 203 mesh points, equivalent to cube‐shaped, packaged material in the practical application. Most of the calculations were performed on a personal computer.
A unique program for integrating health, safety, environment and social aspects into undergraduate chemical engineering education
Authors: Lemkowitz S. M. 
Published: June 2004

AbstractOver the last fifteen years Delft University of Technology has developed a unique educational program in its undergraduate curriculum. In this program health, safety, environmental and social aspects of chemical engineering are studied explicitly in separate courses while being integrated into the whole of educational and research activities. The program's activities include a required (“dedicated”) third year course, Chemical Risk Management, which covers environment as well as safety. There is also a required first year course, Chemistry and Society/Industrial Orientation, which studies how industries and government react to environmental and safety problems. Another required activity is the Safety Report, which fourth year and graduate students must write and have accepted in order to be allowed to carry out laboratory work. All these activities are closely related to and coordinated with one other. The program, which has been followed by more than two thousand students over the last fifteen years, requires extensive cooperation with industry.
Halon replacement: The law and the options
Authors: Senecal Joseph A. 
Published: June 2004

AbstractHalons 1301 and 1211 have been employed widely for over 20 years in a broad array of fire and explosion protection applications. These chemicals, however, have been determined to be environmentally unfriendly due to their high ozone depleting potentials. International treaty, national laws and local ordinances have severely limited the future use of these chemicals. Production in the United States will likely come to an effective halt by 1994. A number of alternative chemicals have been suggested as potential replacements for the halons both in total flooding and streaming agent applications. A comparison of the several viable halon alternatives is made including performance, cost and availability. Areas where new applications data are required are noted.
Using the ASTM CHETAH program in chemical process hazard evaluation
Authors: Frurip David J. 
Published: June 2004

AbstractThe CHETAH program has proven to be of great utility in the assessment of reactive chemicals hazards associated with the development of new chemicals and chemical processes. At the Dow Chemical Company, the most frequent use of the program is for the estimation of heats of reaction. Reaction heats are often the single most important parameter in reactive chemicals evaluation since most “worst case” scenarios involve the instantaneous liberation of the reaction energy. Another common use of the program is using CHETAH's unique capability to predict the “explosive” behavior of a material or mixture solely from a knowledge of its molecular structure. Several examples of day‐to‐day use of the program are presented. Current development activity in the ASTM subcommittee which supports CHETAH are discussed. These include new hazard evaluation criteria, better thermodynamic property estimation techniques, and user friendly versions of the program.
From a local Green's function to molecular charge transport
Authors: Albrecht M. , Schnurpfeil A. , Cuniberti G. 
Published: June 2004

AbstractA local‐orbital basedab initioapproach to obtain the Green's function for large heterogeneous systems is developed. First a Green's function formalism is introduced based on exact diagonalization. Then the self energy is constructed from an incremental scheme, rendering the procedure feasible, while at the same time physical insight into different local correlation contributions is obtained. Subsequently the Green's function is used in the frame of the Landauer theory and the wide band approximation to calculate the electronic transmission coefficient across molecular junctions. The theory is applied to meta‐ and para‐ditholbenzene linked to gold electrodes and various correlation contributions are analyzed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Disorder effects on the properties of two‐dimensional finite systems in perpendicular magnetic field: the tight binding approach
Authors: Aldea A. , Nitţă M. , Dinu V. , Ţolea M. 
Published: June 2004

AbstractWe review some aspects concerning the disorder effects on the spectral properties of 2D electronic systems with relevance for the transport and orbital magnetism in perpendicular magnetic field. The lattice model and random Anderson disorder are used. The discussion is carried out separately for periodic and hard wall boundary conditions. The degree of localization is evidenced by the calculation of the inverse participation number of the eigenstates of the Hamiltonian and a striking asymmetry of the localization effect of states in the Landau band is reported. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Critical properties in long‐range hopping Hamiltonians
Authors: Cuevas E. 
Published: June 2004

AbstractSome properties of d‐dimensional disordered models with long‐range random hopping amplitudes are investigated numerically at criticality. We concentrate on the correlation dimension d2 (for d = 2) and the nearest level spacing distribution Pc(s) (for d = 3) in both the weak (bd ≫ 1) and the strong (bd ≪ 1) coupling regime, where the parameter b− d plays the role of the coupling constant of the model. It is found that (i) the extrapolated values of d2 are of the form d2 = cdbd in the strong coupling limit and d2 = d − ad/bd in the case of weak coupling, and (ii) Pc(s) has the asymptotic form Pc(s) ∼ exp (−Adsα) for s ≫ 1, with the critical exponent α = 2 − ad/bd for bd ≫ 1 and α = 1 + cdbd for bd ≪ 1. In these cases the numerical coefficients Ad, ad and cd depend only on the dimensionality. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local distortions and Friedel oscillations in interacting Fermi chains
Authors: Schuster Cosima , Brune Philipp 
Published: June 2004

AbstractThe interplay between disorder and interaction, especially near metal insulator transitions, is a long‐standing question. We investigate in detail single impurities, in particular, the Friedel oscillations induced by them. We study the decay of the Friedel oscillations in the one‐dimensional Heisenberg and Hubbard model analytically using the bosonization technique and numerically using the density matrix renormalization group treatment (DMRG). For the Heisenberg chain, we confirm the predictions of conformal field theory and bosonization for small interaction, but near phase transitions deviations are found in form of vanishing or additional oscillations. For the Hubbard chain, we study the oscillations – in the density as well as in the magnetization – in the spin‐gap, charge‐gap, and Luttinger liquid phase. We find an exponential decay or a very slow algebraic decay of the oscillations in the gapped phases. In the Luttinger liquid phase, we concentrate on the question of logarithmic corrections (which occur also in the isotropic Heisenberg antiferromagnet). Differences in the behavior near a boundary compared to an impurity are pointed out. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Applying simulation and design of experiments to the embedded software testing process
Authors: Lazić Lj , Velašević D 
Published: June 2004

AbstractThis paper presents some original solutions with regard to the deployment of the U.S. Department of Defense Simulation, Test and Evaluation Process (DoD STEP), using an automated target tracking radar system as a case study. Besides the integration of modelling and simulation, to form a model‐based approach to the software testing process, the number of experiments, i.e. test cases, have been dramatically reduced by applying an optimized design‐of‐experiment plan and an orthogonal array‐based robust testing methodology. Also, computer‐based simulation at various abstraction levels of the system/software under test can serve as a test oracle. Simulation‐based (stochastic) experiments, combined with optimized design‐of‐experiment plans, in the case study have shown a minimum productivity increase of 100 times in comparison to current practice without DoD STEP deployment. Copyright © 2004 John Wiley & Sons, Ltd.
Mycophenolate mofetil, an inhibitor of inosine monophosphate dehydrogenase, causes a paradoxical elevation of GTP in erythrocytes of renal transplant patients
Authors: GOLDSMITH David , CARREY Elizabeth A. , EDBURY Stephen , SMOLENSKI Ryszard T. , JAGODZINSKI Piotr. , SIMMONDS H. Anne 
Published: June 2004

The immunosuppressant MMF (mycophenolate mofetil) has increasingly replaced AZA (azathioprine) in renal transplantation. MMF is a prodrug of MPA (mycophenolic acid), which inhibits lymphocyte IMPDH (inosine monophosphate dehydrogenase), thereby drastically decreasing GTP concentrations essential to lymphocyte proliferation in vitro and in vivo. Erythrocyte GTP concentrations are commonly elevated in severe renal disease, but normalize following successful engraftment. Consequently, elevated GTP in renal transplant recipients might signal impending loss of immunosuppression and graft failure. In the present study, we compared erythrocyte nucleotides and plasma metabolites in two groups of 25 patients after renal transplantation, both receiving prednisolone and cyclosporin A, but one group receiving MMF and the other AZA. No patients had recent allograft biopsy evidence of rejection. Erythrocyte GTP concentrations at MMF commencement were 50.4±23.4 μmol/l. An increase occurred during the first 3 months after transplant when MMF was used de novo, stabilizing at 146.7±62.9 μmol/l after 4 months. This was significantly higher (P=2.5×10−6) than erythrocyte GTP (40.4±15.9 μmol/l) in the AZA group, which was essentially unchanged from values immediately after successful transplantation. The effect of MMF on erythrocyte GTP levels was reversible, since GTP levels fell when MMF therapy was terminated. The results demonstrate paradoxically high GTP concentrations in erythrocytes of renal transplant patients receiving MMF. MPA may stabilize reticulocyte IMPDH, allowing the protein to persist during erythropoiesis. This behaviour is in marked contrast with the decrease in GTP levels seen in white blood cells of patients on chronic MMF therapy.