bluuebunny/crossref_metadata_2025 huggingface dataset:
Design example: Explosion protection selected for a spray drying installation
Authors: Bruderer R. E.
Published: June 2004

A new spray drying installation must withstand a probable dust explosion without endangering personnel. Explosion venting and suppression are considered as well as the reasoning behind the design requirements.
Vapor cloud explosion blast prediction
Authors: van Wingerden C. J. M. , van den Berg A. C. , Opschoor G.
Published: June 2004

A multi‐energy method that uses an idealized gas explosion for predicting vapor cloud explosions is described.
Off site risk assessment and risk minimization guidelines
Authors: Schaller L. C.
Published: June 2004

The du Pont Company has long acknowledged its responsibility for environmental and public safety. In 1938 an Executive Committee resolution cited environmental control as a subject of major concern, and in 1971 that committee called upon each department to determine that their products could be made, used, handled, and disposed of safely.
Stop tank abuse
Authors: Sanders Roy E. , Haines Don L. , Wood James H.
Published: June 2004

Large volumes of fluids are processed or stored in tanks of all shapes and sizes and occupy a major portion of the landscape within our chemical plants and refineries. These tanks serve the industry very well but occasionally they suffer from improper design or abusive conditions and failures occur.
Safe storage of dilute ethylene oxide mixtures in water
Authors: Curtis James S.
Published: June 2004

In the past industry has had to rely on a number of “rules of thumb” to provide a means of reasonable analysis for many design, operation, safety and similar issues. The lack of readily available computing facilities made the use of “rules of thumb” a necessary part of doing business in the hydrocarbon processing industry. And these “rules of thumb” have proven useful and allowed many tasks to be accomplished successfully. Today, however, availability of mainframe computers or desktop computing facilities has provided a tool that has decreased the need to rely on “rules of thumb.” And in many cases processing improvements can only be accomplished by replacing “rules of thumb” with more rigorous analysis. In the ethylene oxide producing/consuming industry a widely‐used “rule of thumb” concerns the storage of ethylene oxide water solutions. A well‐publicized “rule” stated that solutions in excess of 1‐2 weight percent ethylene oxide in water should not be stored [1]. This “rule” is certainly valid in many situations. However, this guideline may be unnecessarily restrictive in other cases. The impact of several key process parameters impacts the amount of ethylene oxide in water than can be safely stored. This study will show that higher concentrations of ethylene oxide in water can be safely stored under the right circumstances. The study will also discuss the key variables that determine whether aqueous ethylene oxide solutions can be safely stored. Finally, a methodology used in determining how much ethylene oxide in water can be safely stored will be outlined.
Safer piping: Awareness training for the process industries
Authors: Hancock Bernard
Published: June 2004

The ‘Safer Piping’ video training package was produced by the International Process Safety Group (IPSG) to meet the urgent need for training material to stem the ever–growing number of accidents directly caused by piping failures. The IPSG, then under the Chairmanship of Bob Mill, Exxon Chemical Corporation, identified piping as the single most important cause of concern in a process plant. The aim was to raise safety standards by changing people's attitudes to piping.
Flow chamber simulations of aerosol formation and liquid jet breakup for pressurized releases of hydrogen fluoride
Authors: Hague William J. , Pepe William
Published: June 2004

Recent Community‐Right‐To‐Know legislation has brought the safety issues of handling, processing and storing toxic chemicals into the public arena. Industry is working with various local response agencies to determine the potential risks to a community from an accidental or episodic release of a chemical. One part of this risk analysis is the requirement to perform a consequence analysis to determine the potential extent of exposure a chemical plume will have for an accidental release. This extent of exposure is typically determined based on plume dispersion computer modeling techniques. Reviews of plume dispersion modeling techniques are described by Hanna and Drivas (1987) [4] and McNaughton, et al. (1986) [7].
Development of leading indicators of process safety
Authors: Van Hemel Susan B. , Connelly Edward M. , Haas Paul M.
Published: June 2004

The goal of this project, sponsored by the US Nuclear Regulatory Commission, is to identify “leading” indicators of nuclear power plant safety. Such indicators would allow early recognition, and perhaps avoidance, of impending safety problems before the problems themselves became evident. Because data are limited in the nuclear industry, CTA's approach to this objective is to look beyond the nuclear power industry, to other industries with safety concerns analogous to those of the nuclear power community, for sources of such indicator data.
Use of DIPPR data in reactive chemical hazard assessment
Authors: Selover Theodore B.
Published: June 2004

In the early 1970's AIChE established the concept of Design Institutes. These are cooperative, industrially sponsored research efforts based on getting work done in an area of general interest at low cost to supporters.

There are now four active AIChE groups. These are, with date of organization: Design Institute for Physical Property Data (DIPPR), 1978; Research Institute for Food Engineering (RIFE), 1984; Center for Chemical Process Safety (CCPS), 1985; and Center for Waste Reduction Technologies (CWRT), 1989. A fifth, Design Institute for Emergency Relief Systems (DIERS) has completed its work and established a user's group. The subject of this paper, DIPPR, is now in its eleventh year of funded project work. A symposium honoring the completion of DIPPR's tenth year was held in San Francisco in November, 1989. There were 11 papers presented, along with an historical overview. Copies of the 11 papers are available from the Engineering Societies Library in New York City, as Session 40. The papers were published as an AIChE Symposium Series in 1990 [1].

The DIPPR project results that can be used in reactive chemical hazard assessment are highlighted.
Hazard materials testing at the U.S. department of energy's liquefied gaseous fuels spill test facility
Authors: Leone F. A.
Published: June 2004

The U.S. Department of Energy (DOE) constructed the Liquefied Gaseous Fuels Spill Test Facility (LGFSTF) to provide a facility on a user‐free basis to private and public sector test sponsors who are concerned with the safety of hazardous liquids and gases. The LGFSTF provides a facility for testing under controlled conditions to determine: patterns of dispersion, mitigation techniques, combustion characteristics, cleanup techniques, environmental impacts, and emergency planning guidelines. A further goal of the LGFSTF Program is to provide a framework for establishing relationships for joint government‐industry participation.
CCPS guidelines for chemical process quantitative risk analysis
Authors: Freeman Raymond A.
Published: June 2004

This paper focuses on the new Guidelines for Chemical Process Quantitative Risk Analysis recently published by the AIChE Center for Chemical Process Safety (CCPS). CCPS was formed soon after the disasters in Mexico City and Bhopal. CCPS was established in 1985 by the AIChE to develop and disseminate technical information for use in the prevention of major chemical accidents. The center is supported by over 60 industrial sponsors in the chemical process industry (CPI), who provide the necessary funding and professional guidance to its technical committees.

The major product of CCPS activities has been a series of guideline books. Table I presents a list of the currently available CCPS guidelines. The first book, Guidelines for Hazard Evaluation Procedures (HEP), presented various structured qualitative techniques (HAZOP, FMEA, etc.) that could be used to identify possible hazards in a chemical facility. The Technical Steering Committee of CCPS decided that a sequel to HEP should be developed which would present quantitative methods for acute process hazards. The Guidelines for Chemical Process Quantitative Risk Analysis (CPQRA) resulted from that decision.
Regulatory initiatives and related activities in the United States
Authors: Burk Arthur F.
Published: June 2004

Prevention of chemical incidents is an important issue in the chemical petroleum industries. This issue is receiving focus and attention from a wide spectrum—Industry, Labor, Professional Associations, Environmental Groups Government and the Public. The purpose of this paper is to review the various regulatory initiatives and related activities regarding chemical process safety.
Human problems with computer control: An update
Authors: Kletz Trevor A.
Published: June 2004

The applications of computer control continue to grow. Incidents can be avoided by the study of previous occurrences. This paper updates “Human Problems with Computer Control” [1] and describes more incidents on computer‐controlled plants. As before, the computers provided new and easier opportunities for making familiar errors.
Inherently safer plants: An update
Authors: Kletz Trevor A.
Published: June 2004

Instead of adding on protective equipment to control hazards, in an inherently safer plant we avoid them by using less of the hazardous material. Another option is to implement safer alternatives. Though the chemical industry has been slow to adopt such designs there has been some progress.
Explosion isolation systems used in conjunction with explosion vents
Authors: Chatrathi K. , DeGood R.
Published: June 2004

A description of the experiments conducted, the results from the experiments and conclusions reached on the basis thereof.
The effect of O2 concentration on methacrylic acid stability
Authors: Nicolson Adrian
Published: June 2004

The effects of oxygen concentration on the stability of methacrylic acid (MAA) have been examined using HQ, MeHQ and PTZ as inhibitors. The O2 has been found to have a dual effect so that an optimum concentration confers very high stability but increased [O2]s give significantly reduced induction periods, especially at higher temperatures. This behavior has been explained in terms of radical scavanging competing with peroxide formation and cleavage. The main parameters controlling the system have been examined. The rate of stabilizer consumption was found to be controlled mainly by temperature and [O2]. The rate of energy release on polymerization is dependent on temperature, [stabilizer] and O2 supply to the system and is rapid (violent in extreme cases) only when all three factors are favorable for efficient peroxide formation and cleavage. Preliminary experiments with n‐butyl methacrylate indicate that the same principles and mechanism operate for the simple methacrylate esters.
Explosion within a helium purifier
Authors: Hempseed J. W. , Ormsby R. W.
Published: June 2004

A cryogenic charcoal adsorber used to purify helium for cylinder filling exploded on August 26, 1988 at an Air Products facility in Belgium. Although the feed gas contained only 1.4% oxygen, calculations confirm that a liquid phase containing approximately 85% oxygen could have formed at the inlet to the bed and soaked into the charcoal. This potent explosive mixture (up to 7 times more powerful than TNT) was probably ignited by the flow surge when the bed depressurized to allow change‐over from a full to an empty bank of cylinders.

Parts of the vessel were recovered up to 250 meters from the installation and windows were cracked by the shock wave at approximately 60 meters. These consequences are consistent with the calculated energy available (approximately 40 lb TNT). Fortunately no one was injured. Two other recent explosions in the industry further emphasize the potential concerns of carbon bed cryogenic purifiers of oxygen containing gases.
The effect of elemental mercury on engineering materials used in ammonia plants
Authors: Wilhelm S. Mark
Published: June 2004

Inappropriate combinations of moisture, alloy and mercury can accelerate corrosion and form explosive compounds. Are there ways of preventing these potential hazards?
Management of hazardous materials at the local community level
Authors: Keffer William J.
Published: June 2004

Increasing media visibility, public concern, and restrictive legislation over the effects of chemicals in use by society is creating a range of problems and liabilities that many local jurisdictions are currently unprepared to cope with. Communities around the nation are struggling to develop cost effective, sustainable internal systems to manage their responsibilities for hazardous chemicals which are used, stored, manufactured or transported within their areas of responsibilities. Within the past few years, federal and state legislation has mandated new local responsibilities for management of chemical hazards. The sheer volume of statutes, regulations, guidance and advice available from public and private sources on how to manage these new responsibilities and liabilities can be overwhelming.
Ammonia vessel integrity program: A modern approach
Authors: Conley Michael J. , Angelsen Sture , Williams David
Published: June 2004

The probability of fracture of an ammonia storage vessel due to stress cracking can be calculated based on the vessel's likelihood of failure.
Sensitivity of process risk to human error in an ammonia plant
Authors: Delboy W. J. , Dubnansky R. F. , Lapp Steven A.
Published: June 2004

Fault tree analysis evaluates the relationship between overall process risk and human failure probabilities. Based on this information, most critical areas of operator training and/or need for automatic systems are determined.
An ammonia storage tank study
Authors: Squire R. H.
Published: June 2004

An in‐depth hazards review and subsequent field work on a 20‐year‐old ammonia tank are discussed, as well as a new method used to change tank valves. Included are a risk assessment of critical piping and a fracture mechanic study of the tank.
Mitigation systems
Authors: Hague William J.
Published: June 2004

The workshop was organized through the presentations in an attempt to achieve the following goals:

Review the state‐of‐the‐art of mitigation techniques.

Establish a preference order for mitigation systems.

Define the tools available to determine the relative benefit of various mitigation systems.

Identify future research needs to enhance or improve mitigation systems.
Review of large‐scale explosion experiments
Authors: Bull David C.
Published: June 2004

The content and bounds of this paper must be understood in the context of the workshop as a whole and of the specific mandate the author was given. The other presentation topics were: “Effect of Turbulence and Confinement”, “Detonations in Vapor Clouds and Explosion Mitigation”, “Application of Blast Estimation Techniques”, “Characteristics of Blast Effects” and “Overview of Analytical and Numerical Computational Methods for Predicting Blast Effects from Vapor Cloud Explosions”. The author's specific mandate was to review the key experiments, to identify their principal findings and conclusions and to discuss applicability to real world situations.
Flashback from waste gas incinerator into air supply piping
Authors: Anderson S. E. , Dowell A. M. , Mynaugh J. B.
Published: June 2004

A waste gas incinerator experienced a flashback with a pressure wave in the Suction Vent Gas (SVG) system. Extensive damage resulted to the SVG flame arrestor, SVG fan, SVG valves, and incinerator piping. There were no injuries. The primary cause of the incident is believed to have been a fuel rich SVG stream that was rapidly introduced into the incinerator creating a “puff.” This “puff” allowed flame from the natural gas ring burner to blow back into the windbox igniting the fuel rich SVG. The combustion of gas in the ducting then created a pressure wave that blew apart the flame arrestor and caused the remainder of the damage.
On‐line modeling of thermally hazardous batch processes
Authors: Gordon Michael D.
Published: June 2004

Reaction kinetics models, which were originally developed to define safe process designs for potentially hazardous batch aminations of nitroaromatics, are being applied on‐line for advisory control. The simulation takes as input live time‐temperature data, and calculates variables such as, conversions, heat‐release rates and pressure profiles. Results are continuously compared to measured data to ensure no unusual safety behavior throughout the reaction cycle. Model outputs also are employed to predict end‐of‐batch conditions to minimize processing times and yield uniform quality products.
Some improvements in design of atmospheric ammonia storage tanks of the double integrity type
Authors: Herbertsson Gunnar
Published: June 2004

This paper describes a new atmospheric ammonia storage tank in Iceland. Some modifications have been made to the former common open cup design of double integrity tanks. Another modification is described, dry air is bled under the cladding of the sidewall insulation to protect the insulation from moisture penetration under the vapor barrier which results in frost damages.
MIACC (major industrial accidents council of Canada): A Canadian consensus group of stakeholders working on safety issues prior to legislation
Authors: Easterbrook John
Published: June 2004

MIACC is a unique not‐for‐profit organization using a consultative process to reduce the risk posed by potential major accidents involving dangerous substances. Working Groups, consisting of partner members, develop products based on recommendations made in the Bhopal Aftermath Review.1 Consensus reports, approved by the stakeholder, result in National Standards and Guidelines which are intended to be practical and acceptable to industry and government alike.
Emergency pressure relief discharge control by passive quenching—update
Authors: Keiter Alan G.
Published: June 2004

A recent runaway reaction emergency relief system design includes a passive quench tank to collect and contain the two‐phase emergency relief discharge. This avoids the release of a large vapor cloud to the atmosphere and the attendant flammability and toxicity hazards. The feasibility of quenching is demonstrated with small scale experiments. A pressure relief simulation model is shown to accurately reproduce the observed temperature and pressure profiles in both the reactor and quench tank during relief. The model is then applied to the design of a full scale system. Quench system design considerations are discussed.
Dust explosion prevention by addition of thermal inhibitors
Authors: Amyotte Paul R. , Pegg Michael J.
Published: June 2004

Combustible dusts such as flour, sugar, metals, plastics and coal are produced as end‐ or by‐products in many industries, including the chemical process industries. The risk of fire or explosion in the handling of these dusts has prompted considerable research effort in the areas of explosion prevention and mitigation. While this work has generally resulted in safer plant operation, the dust explosion hazard has not been eliminated.
Electrostatic hazards of pneumatic conveying of powders
Authors: James Dahn C.
Published: June 2004

The potential for dust explosion from electrostatic discharge in pneumatic Conveying systems has been reviewed. The importance of lab testing to determine electrostatic charging of powders in contact with materials of construction is illustrated. Correlation of predicted voltage fields (from lab testing) to full scale is good. With the voltage field information, ESD potential at various parts of the pneumatic conveying system can be determined (primarily in receivers, silo and separator).
IT‐Security‐Ping‐Pong: IT‐Risk‐Management muss ganzheitlich betrachtet werden
Authors: Romeike Frank , Erben Roland Franz
Published: June 2004

„Kann et losgahn?”︁ seggt' de Haas'. „Ja wol”︁ seggt' de Swinegel. „Denn man to”︁ un damit stellde jeder sick in siene Föhr, de Haas' tellde: „Hahl Een! Hahl Twee! Hahl Dree!”︁ un los güng he wi en Stormwind, den Acker hindahl. De Swinegel aver löp ungefähr man dree Schritt, dann duhkde he sick dahl in de Föhr un blev ruhig sitten. As nu de Haas' in vullen Lopen ünnen am Acker anköm, röp em den Swinegel sien Fro entgegen: „Ick bün all hier!”︁
Blick durch das Schicksalsfenster: Sonne oder Sturm? — Strategieentwicklung mit der SWOT‐Matrix
Authors: Wagemann Bernard
Published: June 2004

Die SWOT‐Matrix ist ein einfaches und bewährtes Instrument zur Darstellung der strategischen Situation eines Unternehmens: Sie stellt außenbedingte Chancen und Risiken sowie unternehmensbedingte Stärken und Schwächen einander gegenüber und ist gewissermaßen das Herzstück der Strategieentwicklung. Trotzdem findet man in der Fachliteratur kaum einen effizienten Ansatz zur Auswertung dieser Matrix. Die hier vorgestellte Methode der Fokusanalyse bietet ein praxiserprobtes Instrument, um die vier Fenster der SWOTMatrix in ihrer Bedeutung konsequent zu interpretieren und strategische Schwerpunktaufgaben abzuleiten.
Motivation des schwächsten Glieds — Der Faktor Mensch wird im IT Risk Management (wieder)entdeckt!
Authors: Romeike Frank , Erben Roland Franz
Published: June 2004

Das Fundament jedes Risk‐Management‐Prozesses und die Grundlage jeder Risiko‐Steuerung ist ein angemessenes Risiko‐Bewusstsein. Dieses Risiko‐ Bewusstsein ist wiederum stark von der Risiko‐Wahrnehmung abhängig. Was für den Einen ein Risiko ist, braucht für den Anderen noch lange keines zu sein. Denn Risiko ist ein Konstrukt. Risiko ist das subjektive Resultat der Eindrücke, die wir über unsere Augen, Ohren, unsere Nase, unseren Tastsinn und unsere Geschmacksorgane aufnehmen. Unsere fünf Sinne gaukeln uns möglicherweise Risiken vor, die sich später nur als Illusion erweisen. Oder unser Gehirn nimmt bestimmte Risiken gar nicht mehr wahr, weil es glaubt, vor ihnen sicher zu sein — etwa, wenn wir im IT‐Bereich bereits alle möglichen technischen Maßnahmen wie Firewalls, Intrusion Detection Systeme etc. eingeführt haben. Manchmal sehen wir eben vor lauter Bäumen den Wald nicht mehr.
Experimental reintroduction of woody debris on the Williams River, NSW: geomorphic and ecological responses
Authors: Brooks Andrew P. , Gehrke Peter C. , Jansen John D. , Abbe Tim B.
Published: June 2004

A total of 436 logs were used to create 20 engineered log jams (ELJs) in a 1.1 km reach of the Williams River, NSW, Australia, a gravel‐bed river that has been desnagged and had most of its riparian vegetation removed over the last 200 years. The experiment was designed to test the effectiveness of reintroducing woody debris (WD) as a means of improving channel stability and recreating habitat diversity. The study assessed geomorphic and ecological responses to introducing woody habitat by comparing paired test and control reaches. Channel characteristics (e.g. bedforms, bars, texture) within test and control reaches were assessed before and after wood placement to quantify the morphological variability induced by the ELJs in the test reach. Since construction in September 2000, the ELJs have been subjected to five overtopping flows, three of which were larger than the mean annual flood. A high‐resolution three‐dimensional survey of both reaches was completed after major bed‐mobilizing flows. Cumulative changes induced by consecutive floods were also assessed. After 12 months, the major geomorphologic changes in the test reach included an increase in pool and riffle area and pool depth; the addition of a pool–riffle sequence; an increase by 0.5–1 m in pool–riffle amplitude; a net gain of 40 m3 of sediment storage per 1000 m2 of channel area (while the control reach experienced a net loss of 15 m3/1000 m2 over the same period); and a substantial increase in the spatial complexity of bed‐material distribution. Fish assemblages in the test reach showed an increase in species richness and abundance, and reduced temporal variability compared to the reference reach, suggesting that the changes in physical habitat were beneficial to fish at the reach scale. Copyright © 2004 John Wiley & Sons, Ltd.
Assessing variation in suitability curves and electivity profiles in temporal studies of fish habitat use
Authors: Vilizzi Lorenzo , Copp Gordon H. , Roussel Jean‐Marc
Published: June 2004

Under experimental conditions, we tested whether variations in preference curves, weighted usable areas, and electivity profiles for velocity of 0+ juvenile barbel Barbus barbus could be attributed to environmental variables (discharge, water depth, time of day) and/or time of sampling. We elaborated preference curves and weighted usable areas according to the Instream Flow Incremental Methodology, as well as electivity profiles. Variation among preference curves, weighted usable areas and electivity profiles was always observed, regardless of time of day, water depth, or discharge combinations. Our results support published concerns that the shape of preference curves is highly dependent on the time of data collection, and that curves derived from a single field sampling excursion can be viewed as representative for that moment in time only, whereas curves generated as composites from typological or time‐series samples may provide an approximation for a study area, but at the expense of between‐site and/or between‐date variation. Spatial/temporal variation is an important aspect of fish habitat studies and should be incorporated as a (layered) component into descriptive/predictive models. To this end, we illustrate how a PCA‐based technique and log‐linear modelling can be used to assess temporal patterns in collections of preference curves and electivity profiles, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
Re‐evaluation of heat flow data near Parkfield, CA: Evidence for a weak San Andreas Fault
Authors: Fulton Patrick M. , Saffer Demian M. , Harris Robert N. , Bekins Barbara A.
Published: June 2004

Improved interpretations of the strength of the San Andreas Fault near Parkfield, CA based on thermal data require quantification of processes causing significant scatter and uncertainty in existing heat flow data. These effects include topographic refraction, heat advection by topographically‐driven groundwater flow, and uncertainty in thermal conductivity. Here, we re‐evaluate the heat flow data in this area by correcting for full 3‐D terrain effects. We then investigate the potential role of groundwater flow in redistributing fault‐generated heat, using numerical models of coupled heat and fluid flow for a wide range of hydrologic scenarios. We find that a large degree of the scatter in the data can be accounted for by 3‐D terrain effects, and that for plausible groundwater flow scenarios frictional heat generated along a strong fault is unlikely to be redistributed by topographically‐driven groundwater flow in a manner consistent with the 3‐D corrected data.
On the spatial and temporal relationship between auroral intensification and flow enhancement in a pseudosubstorm event
Authors: Liang Jun , Sofko G. J. , Donovan E. F.
Published: June 2004

We present a joint study of substorm growth phase flow enhancements observed by Super Dual Auroral Radar Network HF radars and auroral optical intensifications observed by Canadian Auroral Network for the OPEN Program Unified Study meridian‐scanning photometers (MSPs). During the event time, 0426–0500 UT on 26 December 1998, a flow enhancement structure was observed by HF radar from just equatorward of the polar cap boundary, whose location is estimated from the MSP observation of the poleward edge of 630 nm emissions, down to 68.5° ± 0.4° magnetic latitude, which is the boundary between the boundary plasma sheet and the central plasma sheet (CPS) inferred from the analysis of radar Doppler spectral widths. We suggest that the flow enhancements were associated with the tail reconnection process in response to the solar wind activation. The auroral optical intensifications were located inside the CPS. A zonal flow shear region characteristic of the Harang discontinuity was also inferred from the radar observation and was found to be closely associated with the auroral intensification structure. The flow enhancement and auroral intensifications were well correlated and occurred almost simultaneously. We found that existing models associating the tail reconnection process and near‐geosynchronous onset of substorms do not explain this temporal relationship very well, and thus we propose a new model.
Cenozoic mass accumulation rates in the equatorial Pacific based on high‐resolution mineralogy of Ocean Drilling Program Leg 199
Authors: Vanden Berg Michael D. , Jarrard Richard D.
Published: June 2004

We use continuous mineralogy logs derived from multisensor track physical properties data and reflectance spectroscopy to calculate high‐resolution carbonate, opal, and terrigenous mass accumulation rates (MAR) for the eight sites cored during Ocean Drilling Program Leg 199 in the equatorial Pacific. The largest change in equatorial Pacific sedimentation patterns of the last 55 Myr occurs at the greenhouse/icehouse transition, shortly after the Eocene/Oligocene boundary. Calcite compensation depth deepened dramatically, the equatorial zone of opal accumulation narrowed, and the intertropical convergence zone shifted to the equator. During the Paleogene the opal equatorial accumulation bulge extended to about 12°N, whereas the Neogene bulge extended only to about 7°N. Very low Eocene carbonate MAR was followed by much higher Oligocene and early Miocene MAR, with the carbonate equatorial bulge extending to 4°N. Terrigenous MARs indicate the paleoposition of the intertropical convergence zone and a Pliocene‐Pleistocene increase in Asian dust flux.
A 2000‐year record of Caribbean and tropical North Atlantic hydrographic variability
Authors: Black David E. , Thunell Robert C. , Kaplan Alexey , Peterson Larry C. , Tappa Eric J.
Published: June 2004

Here we present near‐annually resolved oxygen isotope records from two species of planktic foraminifera from the Cariaco Basin that reflect sea surface temperature (SST) and Intertropical Convergence Zone (ITCZ) precipitation‐related salinity variations over the Caribbean and tropical North Atlantic spanning the last 2000 years. A strong, broad spatial pattern of correlation exists between foraminiferal δ18O and SSTs over the period of instrumental overlap, but the correlations weaken as they are extended back in time and instrumental SST records become discontinuous. A long‐term trend in the Globigerinoides ruber δ18O record can be explained by two different but equally plausible scenarios. First, the increase in δ18O may indicate that tropical summer‐fall SSTs have cooled by as much as 2°C over the last 2000 years, possibly as a result of a long‐term increase in upwelling intensity. Alternately, comparisons to other studies of ITCZ and regional evaporation/precipitation variability suggest that much of the δ18O record is influenced by decadal‐ to centennial‐scale variations in the mean annual position of the ITCZ and associated rainfall patterns. Similarities between the G. bulloides δ18O record and the 11‐year sunspot cycle support prior studies that suggest solar variability plays a role in influencing the hydrologic balance of the circum‐Caribbean.
A comparison of geographical information systems–based algorithms for computing the TOPMODEL topographic index
Authors: Pan Feifei , Peters‐Lidard Christa D. , Sale Michael J. , King Anthony W.
Published: June 2004

The performance of six geographical information systems (GIS)‐based topographic index algorithms is evaluated by computing root‐mean‐square errors of the computed and the theoretical topographic indices of three idealized hillslopes: planar, convergent, and divergent. In addition to these three idealized cases, two divergent hillslopes with varying slopes, i.e., concave (slopes decrease from top to bottom) and convex (slopes increase from top to bottom) are also tested. The six GIS‐based topographic index algorithms are combinations of flow direction and slope algorithms: i.e., single flow direction (SFD), biflow direction (BFD), and multiple flow direction (MFD) plus methods that determine slope values in flat areas, e.g., W‐M method [Wolock and McCabe, 1995] and tracking flow direction (TFD) method. Two combinations of horizontal resolution and vertical resolution of the idealized terrain data are used to evaluate those methods. Among those algorithms the MFD algorithm is the most accurate followed by the BFD algorithm and the SFD algorithm. As the vertical resolution increases, the errors in the computed topographic index for all algorithms decrease. We found that the orientation of the contour lines of planar hillslopes significantly influences the SFD's computed topographic index. If the contour lines are not parallel to one of eight possible flow directions, the errors in the SFD's computed topographic index are significant. If mean slope is small, TFD becomes more accurate because slope values in flat areas are better estimated.
Relationship between overnight neuroendocrine activity and morning haemostasis in working men
Authors: von KÄNEL Roland , KUDIELKA Brigitte M. , ABD-el-RAZIK Adham , GANDER Marie-Louise , FREY Karl , FISCHER Joachim E.
Published: June 2004

Sustained effects of SNS (sympathetic nervous system) and HPAA (hypothalamic–pituitary–adrenal axis) hyperactivity on haemostasis have not been investigated. In the present study, we tested for an association of overnight urinary catecholamine and cortisol excretion with morning plasma levels of fibrinogen, PAI-1 (plasminogen activator inhibitor-1) and D-dimer. Participants (639 male industrial employees) with a complete dataset were studied (age, 41±11 years; mean±S.D.). Subjects collected overnight urinary samples and had a fasting morning blood sample drawn. Measurement of urinary adrenaline (epinephrine), noradrenaline (norepinephrine) and cortisol were dichotomized to perform multivariate analyses of (co)variance. Haemostatic parameters were measured by ELISA. Fibrinogen was higher in men with high adrenaline (F7,631=5.68, P=0.018; where the subscripted value represents the degrees of freedom) and high noradrenaline (F7,631=4.19, P=0.041) compared with men with low excretion of the respective hormones. PAI-1 was higher in men with high cortisol than in men with low cortisol (F7,631=4.77, P=0.029). Interaction revealed that subjects with high cortisol/low noradrenaline had higher PAI-1 than subjects with low cortisol/high noradrenaline (P=0.038). Subjects with high adrenaline/high noradrenaline had higher D-dimer than subjects with high adrenaline/low noradrenaline (P=0.029), low adrenaline/high noradrenaline (P=0.022) and low adrenaline/low noradrenaline (not significant). When covariance for several confounders of haemostatic function was determined, the main effect of adrenaline on fibrinogen and the interaction between adrenaline and noradrenaline for D-dimer maintained significance. Although overnight SNS hyperactivity was associated independently with morning hypercoagulability, the relationship between the activity of HPAA and haemostasis was mediated by traditional cardiovascular risk factors.
Low melatonin excretion during mechanical ventilation in the intensive care unit
Authors: FRISK Ulla , OLSSON Joel , NYLÉN Per , HAHN Robert G.
Published: June 2004

Biochemical markers for the circadian rhythm were studied in patients treated at the ICU (intensive care unit) of two regional hospitals. A normal rhythm is characterized by a relatively higher melatonin and a lower cortisol excretion at night. Disturbances affect sleep, mood and cognitive performance. All urine excreted between 07:00 and 22:00 hours (day) and between 22:00 and 07:00 hours (night) was collected and sampled throughout the entire ICU period (median, 10 days) in 16 patients for the excretion of 6-SMT (6-sulphatoxymelatonin), which is a metabolite of melatonin, and free cortisol. The overall excretion of 6-SMT was slightly lower and the cortisol excretion higher than reported for healthy reference populations. Mechanical ventilation was associated with a markedly lower 6-SMT excretion (median, 198 ng/h) compared with periods without such help (555 ng/h; P<0.0001), whereas infusion of adrenergic drugs increased the 6-SMT excretion (P<0.01). Five patients (31%) showed a virtually absent melatonin excretion for 24 h or more. The diurnal rhythms were consistently or periodically disturbed in 65% and 75% of the patients. These alterations cannot be explained by excessive exposure to light at night. In conclusion, there was hyposecretion of melatonin during mechanical ventilation, an overall high cortisol excretion and a disturbed diurnal rhythm of both of these hormones in most patients treated in two ICU departments.
Evidence for a complex risk profile in obese postmenopausal Turkish women with hypertriglyceridaemia and elevated apolipoprotein B
Authors: ONAT Altan , YAZICI Mehmet , CAN Günay , SNIDERMAN Allan
Published: June 2004

The aim of the present study was to examine possible pathophysiological relationships among a wide array of proatherogenic risk factors in postmenopausal women. Fasting lipids, apoB (apolipoprotein B), BMI (body mass index) and waist circumference were measured in 178 women (59.4±7.2 years) from the Turkish Adult Risk Factor Study. Fasting levels of complement C3, insulin, SHBG (sex hormone-binding globulin), cortisol, oestradiol, testosterone and DHEA-S (dehydroepiandrosterone sulphate) were also determined. This is the first study to examine the relationships of all these variables with apoB. In the first of two different approaches, three groups of obese women were compared. Group 1 comprised women who were normolipidaemic with normal apoB; group 2, women who were hypertriglyceridaemic, but with normal apoB; and group 3, women who were hypertriglyceridaemic with elevated apoB. Complement C3, fasting insulin and glucose were significantly higher and HDL-C (high-density lipoprotein-cholesterol) and SHBG levels were significantly lower in group 3 than in group 1. In the former group, the testosterone/SHBG ratio tended to be higher, indicating more free testosterone, than in group 1. The mean risk score in group 3 and the odds ratio for coronary disease by logistic regression analysis were significantly higher, 2.56 (confidence intervals, 1.12–5.85; P=0.026), compared with the two other groups combined. In examining the whole group, apoB levels correlated significantly with a wider array of pro-atherogenic risk factors than did LDL-C (low-density lipoprotein-cholesterol), particularly being linked to complement C3 and glucose, as well as the risk score. Complement C3 demonstrated the widest associations and was significantly linked with BMI, waist circumference, insulin, glucose, fibrinogen, triacylglycerols (triglycerides) and apoB and was inversely correlated with HDL-C and SHBG. SHBG was also correlated inversely with a wide spectrum of risk variables. In summary, in Turkish women, apoB was linked with a complex array of proatherogenic risk factors, and hypertriglyceridaemia with elevated apoB was associated with a higher risk of coronary disease.
Defying death: the hepatocyte's survival kit
Authors: SCHOEMAKER Marieke H. , MOSHAGE Han
Published: June 2004

Acute liver injury can develop as a consequence of viral hepatitis, drug- or toxin-induced toxicity or rejection after liver transplantation, whereas chronic liver injury can be due to long-term exposure to alcohol, chemicals, chronic viral hepatitis, metabolic or cholestatic disorders. During liver injury, liver cells are exposed to increased levels of cytokines, bile acids and oxidative stress. This results in death of hepatocytes. In contrast, stellate cells become active and are resistant against cell death. Eventually, acute and chronic liver injury is followed by loss of liver function for which no effective therapies are available. Hepatocytes are well equipped with protective mechanisms to prevent cell death. As long as these protective mechanisms can be activated, the balance will be in favour of cell survival. However, the balance between cell survival and cell death is delicate and can be easily tipped towards cell death during liver injury. Therefore understanding the cellular mechanisms controlling death of liver cells is of clinical and scientific importance and can lead to the identification of novel intervention targets. This review describes some of the mechanisms that determine the balance between cell death and cell survival during liver diseases. The strict regulation of apoptotic cell death allows therapeutic intervention strategies. In this light, receptor-mediated apoptosis and mitochondria-mediated cell death are discussed and strategies are provided to selectively interfere with these processes.
Non-Hermitian quantum mechanics: Wave packet propagation on autoionizing potential energy surfaces
Authors: Moiseyev N. , Scheit S. , Cederbaum L. S.
Published: June 2004

The correspondence between the time-dependent and time-independent molecular dynamic formalisms is shown for autoionizing processes. We demonstrate that the definition of the inner product in non-Hermitian quantum mechanics plays a key role in the proof. When the final state of the process is dissociative, it is technically favorable to introduce a complex absorbing potential into the calculations. The conditions which this potential should fulfill are briefly discussed. An illustrative numerical example is presented involving three potential energy surfaces.
Strong 1.3–1.5 μm luminescence from Ge/Si self-assembled islands in highly confining microcavities on silicon on insulator
Authors: El Kurdi M. , David S. , Boucaud P. , Kammerer C. , Li X. , Le Thanh V. , Sauvage S. , Lourtioz J.-M.
Published: June 2004

We report dramatic enhancement of 1.3–1.5 μm room-temperature emission from self-assembled Ge/Si islands in highly confining microcavities on silicon on insulator. The microcavities are fabricated either by creating defects in two-dimensional silicon-based photonic crystals or by etching the silicon layer in order to form isolated micropillars. The optical emission is characterized by nonlinear evolution with pump power, the nonlinearity being more pronounced as the microcavity size is reduced. Both the nonlinearity and luminescence extraction are enhanced in photonic crystals with large air filling factors. The results are interpreted in terms of carrier localization. The luminescence extracted is more than two orders of magnitude higher than that of the unprocessed sample while it is 1% that of a single InGaAs quantum well. This system appears to be a promising alternative for microsources on silicon at telecommunication wavelengths that are fully compatible with silicon-based processing technologies.
Migration of Te atoms and structural changes in CdS/CdTe heterojuctions studied by x-ray scattering and fluorescence
Authors: Kim S. , Soo Y. L. , Kioseoglou G. , Kao Y. H. , Compaan A. D.
Published: June 2004

X-ray reflectivity and angular dependence of x-ray fluorescence (ADXRF) techniques have been employed for a quantitative study of the Te depth profile and structural changes in a series of CdS/CdTe heterojuctions annealed at various temperatures. The temperature dependence of surface roughening and Te migration is observed in both reflectivity and fluorescence experiments. Changes in the interface morphology and Te distribution are quantified by detailed analysis of the ADXRF data with the aid of reflectivity measurements. The results show that a large amount of Te up to 50% could migrate into the CdS layer and suggest that an extra layer of compounds can be formed near the CdS top surface. We have thus demonstrated that the x-ray reflectivity and ADXRF methods can be used as effective tools for nondestructive characterization of the concentration depth profile and interface morphology in layered structures on a nanometer scale.
Diffusion profiles of high dosage Cr and V ions implanted into silicon
Authors: Zhang P. , Stevie F. , Vanfleet R. , Neelakantan R. , Klimov M. , Zhou D. , Chow L.
Published: June 2004

The depth profiles of high dosage Cr+52 and V+51 ions implanted in (100) crystalline silicon after thermal anneal at temperatures between 300 °C and 1000 °C are studied by secondary ion mass spectrometry and cross-sectional transmission electron microscopy. At dosages of 1×1015 ions/cm2 and above, the surface layer of silicon substrate is amorphorized. During the subsequent thermal annealing, the depth profiles of the implanted ions are strongly coupled with the solid phase epitaxial growth of amorphous silicon. Silicide precipitate formation is important to understand the differences between Cr and V diffusion. After anneal of the 1×1015 ions/cm2 implanted samples at 900 °C and 1000 °C, most of the Cr has left the silicon, but only 10% of the V has escaped. The 1×1014 ions/cm2 Cr-implanted sample shows Cr ions exist only near the surface after 1000 °C anneal. The V-implanted sample, on the other hand, only shows a narrowing of the V profile after 1000 °C anneal.
Mechanism of crystallization of oxygen-doped amorphous Ge1Sb2Te4 thin films
Authors: Rivera-Rodrı́guez C. , Prokhorov E. , Trapaga G. , Morales-Sánchez E. , Hernandez-Landaverde M. , Kovalenko Yu. , González-Hernández J.
Published: June 2004

The aim of this article is to study the mechanism of the amorphous-to-crystalline phase transformation in Ge1Sb2Te4 alloys doped by oxygen (in the range of 4–28 at. %) using the electrical, optical, and x-ray measurements. Experimental results have shown that samples with oxygen in the range of about 4–10 at. % first crystallize into the Ge1Sb2Te4 fcc phase at temperatures in the range 130–145 °C, at higher temperature (around 275 °C) the fcc phase is transformed into the Ge1Sb2Te4 hexagonal phase. In samples with oxygen in the range of 10–15 at. % the crystallization occurs in two stages producing samples where Ge1Sb2Te4 and the Sb2Te3 coexist. Samples with higher oxygen content, in the range of 15–28 at. % the films crystallized into the rhombohedral Sb2Te3 phase due to the formation of amorphous germanium oxide. The experimental results have been interpreted employing the Johnson–Avrami–Mehl–Kolmogorov theory. Using isothermal measurements and the time dependence of the Avrami exponent, three different crystallization mechanisms are proposed for material with different content of oxygen.
Characteristics of plasma display panel with ridged dielectric and hollow gap between sustain electrodes
Authors: Nam Mun-Ho , Kim Jung-Min , Choi Sie-Young , Son Seung-Hyun , Kim Young-Mo
Published: June 2004

This article presents a front panel structure for an alternating current plasma display panel (AC-PDP) based on a ridged transparent dielectric layer and long hollow gap between the sustain electrodes. The suggested structure can reduce a firing voltage and sustain voltage than a conventional AC-PDP due to a strong electric field between the sustain electrodes. Experiments were conducted with various Xe contents from 10% to 50% at a gas pressure of 450 Torr, and the results confirmed that the ridged dielectric structure reduce the firing and sustain voltages by about 74 and 79 V at 10% Xe content than a conventional structure with 10% Xe content, respectively. Also, the proposed structure improve the luminous efficiency and luminance by about 50.9% and 33%, respectively, with a 50% Xe content when compared to a conventional structure with a 10% Xe content at a similar driving voltage.