bluuebunny/crossref_metadata_2025 huggingface dataset:
The relative effects of fuel concentration, residual-gas fraction, gas motion, spark energy and heat losses to the electrodes on flame-kernel development in a lean-burn spark ignition engine
Authors: Aleiferis P G , Taylor A M K P , Ishii K , Urata Y
Published: April 2004

The potential of lean combustion for the reduction in exhaust emissions and fuel consumption in spark ignition engines has long been established. However, the operating range of lean-burn spark ignition engines is limited by the level of cyclic variability in the early-flame development stage that typically corresponds to the 0-5 per cent mass fraction burned duration. In the current study, the cyclic variations in early flame development were investigated in an optical stratified-charge spark ignition engine at conditions close to stoichiometry [air-to-fuel ratio (A = 15] and to the lean limit of stable operation (A/F = 22). Flame images were acquired through either a pentroof window (‘tumble plane’ of view) or the piston crown (‘swirl plane’ of view) and these were processed to calculate the intra-cycle flame-kernel radius evolution. In order to quantify the relative effects of local fuel concentration, gas motion, spark-energy release and heat losses to the electrodes on the flame-kernel growth rate, a zero-dimensional flame-kernel growth model, in conjunction with a one-dimensional spark ignition model, was employed. Comparison of the calculated flame-radius evolutions with the experimental data suggested that a variation in A/F around the spark plug of Φ(A/F) ≈ 4 or, in terms of equivalence ratio Φ, a variation in Φ ≈ 0.15 at most was large enough to account for 100 per cent of the observed cyclic variability in flame-kernel radius. A variation in the residual-gas fraction of about 20 per cent around the mean was found to account for up to 30 per cent of the variability in flame-kernel radius at the timing of 5 per cent mass fraction burned. The individual effect of 20 per cent variations in the ‘mean’ in-cylinder velocity at the spark plug at ignition timing was found to account for no more than 20 per cent of the measured cyclic variability in flame kernel radius. An individual effect of similar level was attributed to the heat losses to the electrodes, and a much lower effect than that, namely 5-10 per cent at most, could be attributed to cyclic variations in spark-energy release traces. Even when the variations in mean velocity were coupled to both the effects of heat losses to the electrodes and spark-energy release variations, the combined effect was found to account for no more than 40-50 per cent of the observed cyclic variability in flame-kernel radius at the 5 per cent mass-fraction burned timing of 40 ° crank angle after ignition timing.
Experimental investigation of the effect of thin-wall substrates and spark timing retard on total hydrocarbon emissions during cold start for super-ultra-low-emission vehicle application
Authors: Myung Cha-Lee , Park Simsoo , Kim Han-Sang , Min Kyoungdoug , Choi Myung-Sik
Published: April 2004

As the basic approach to improve the emission performance under cold start engine operation to meet stringent emission regulations, the effects of thin wall catalysts and spark timing retard on total hydrocarbon (THC) emission characteristics were investigated by engine performance and vehicle emissions tests. From this study, the effects of cell density on back pressure and engine performance were studied for thin-wall catalysts. The light-offtime reduction of the thin-wall catalysts was also demonstrated through vehicle emission tests.

The effect of spark timing retard from minimum spark advance for best torque on THC emission reduction under the cold-start condition was also studied quantitatively using a fast flame ionization detector and a flame visualization technique. As the spark timing is retarded, THC emission at the exhaust manifold is effectively reduced regardless of the air-fuel ratio. From flame visualization, as the spark timing is retarded, the flame propagation speed becomes slower and the duration of the main flame is longer. It was also found that the reduction in THC emission at the beginning of the engine start is essential to meet the more stringent emission regulations.

As a result, the adoption of a high-cell-density catalyst (900 cells/2.0 mil) and the spark timing retard technique (spark advance retard case, after top dead centre 8 ° crank angle) makes it possible to meet the super-ultra-low-emission vehicle emission regulation if effectively combined along with a metallic catalyst and exhaust gas-flow-optimized exhaust manifold.
Engine performance and emissions of a compression ignition engine operating on the diesel-methanol blends
Authors: Huang Z H , Lu H B , Jiang D M , Zeng K , Liu B , Zhang J Q , Wang X B
Published: April 2004

A stabilized diesel-methanol blend was realized and a study on the performance and emissions of the diesel-methanol blend was carried out in a compression ignition engine. The study showed that the engine thermal efficiency increases and the diesel equivalent b.s.f.c. decreases with increase in the oxygen mass fraction (or methanol mass fraction) of the diesel-methanol blends due to an increased fraction of premixed combustion phase, oxygen enrichment and improvement in the diffusive combustion phase. Further increase in the fuel delivery advance angle will achieve a better engine thermal efficiency when the diesel engine is operated using the diesel-methanol fuel blends. A marked reduction in the exhaust CO and smoke can be achieved when operating with the diesel-methanol blend. There is not a large variation in the exhaust hydrocarbon with the addition of methanol in diesel fuel. NOx increases with increase in the mass of methanol added; methanol addition to diesel fuel was found to have a strong influence on the NOx concentration at high engine loads rather than at low engine loads, and a flat NOx-smoke trade-offcurve exists when operating with the diesel-methanol fuel blends.
Value Change in Oil and Gas Production VI. Buy-Out, Farm-Out, or Stand
Authors: Lerche I. , Noeth S.
Published: April 2004

Often a corporation has an immediate cash need, either to avoid insolvency or for further opportunities it deems to be likely highly lucrative. In such a situation a corporation will often attempt to farm-out a percentage of a profitable field, or attempt a complete buy-out so that the corporation can meet its immediate cash needs. Here we show how one can quantitatively evaluate the farm-out price and fraction, or the buy-out price, most likely to lead to acceptance by a tendering corporation, and still maintain the highest chance of realizing the immediate cash needs. When parameters involved in the estimates of future field worth, future costs, and allied field-related parameters are themselves uncertain, we also provide a stochastic procedure that enables one to determine not only the greatest probability of a range of farm-out or buy-out prices being accepted, but which also enables one to determine which of the uncertain parameters is causing the greatest uncertainty. In this way one can see where to improve resolution should it be deemed necessary based on the total uncertainty and volatility of the estimated success chances. Numerical examples are given to illustrate all the various components of the deterministic farm-out considerations as well as the buy-out scenarios, and also for the uncertain parameter situations.
Optimum Working Interest in Hydrocarbon Exploration Projects: The High Gain Situation Revisited for Cost, Wealth and Fear Factors
Authors: Lerche I. , MacKay J. A.
Published: April 2004

In exploration ventures where a high gain can be anticipated if the venture is successful, the risk adjusted value shows an anomalous behaviour with increasing value of the venture such that the optimum working interest first increases and then decreases as the value increases. This paradoxical behaviour was “resolved” previously by going outside the framework of the corresponding risk adjusted value formula and adding extraneous constraints. The present paper shows that a complete resolution to the paradox is available while staying precisely within the bounds of the corresponding risk adjusted value formula and without any extraneous constraints. This novel resolution allows one to use many of the risk adjusted formulae available under more general conditions than were thought to be relevant because of the appearance of what seemed to be an insurmountable paradox. A few simple numerical examples are provided to show how one handles this new resolution in pragmatic situations.
Southeastern Anatolia Project (GAP) of Turkey and Regional Development Applications
Authors: Balat Mustafa
Published: April 2004

Southeastern Anatolia Project (GAP: Guneydogu Anadolu Projesi in Turkish) is the largest regional development project in Turkey, and also one of the major projects in the world. There are 13 major projects in the lower Euphrates and Tigris basins that consist of dam's hydropower plants and irrigation schemes and accompanying growth of agriculture, transportation, industry, telecommunications, health and education sectors and services in the region. A total of 22 dams and 19 hydropower plants are to be constructed by DSI. After completion of the project, 1.7 million hectares of land will be irrigated and the ratio of irrigated land to the total GAP area will increase from 2.9 percent to 22.8 percent while that for rain-fed agriculture will decrease from 34.3 percent to 7 percent. The GAP area is bigger than Holland, Denmark, Belgium, Ireland and Luxembourg.
Turkey's Water Resources and Hydropower Potential
Authors: Demirbaş Ayhan , Bakiş Recep
Published: April 2004

The aim of this paper is to investigate the water sources in Turkey. Annual rainfall varies from 220 mm to 2500 mm with an average of 643 mm, which means total volume of 501 km3 and average annual potential of surface water is 186 km3 and 95 km3 of this amount potential can be feasibly developed. Ground water reservoirs are estimated to be around 12 km3. As a result of construction of 700 dams, with different types, purposes and sizes, 140 km3 of water is being stored in the reservoirs. Total hydropower potential of Turkey is annually 433,000 GWh. Almost 50% of the total potential is technically exploitable, and 29% is (122,322 GWh/year) economically exploitable.
Production from Multiple Horizons: Correlation and Uncertainty Considerations
Authors: Lerche I.
Published: April 2004

This paper shows how to incorporate uncertainty on whether two horizons being considered for drilling are correlated or independent. Prior to actual drilling there is no way to be sure of the state of the two horizons in relation to each other. We show that this uncertainty automatically adds an uncertainty to the mean assessed resource estimate and that this uncertainty can dominate over uncertainties brought about by imperfect knowledge of the success probabilities and potential resources of each of the individual horizons, as well as the distributions chosen to represent such uncertainties, and the nominal values of the parameters and their skewness of dynamic range around the nominal values. The main aim is to show which factors dominate in assessments of uncertainty of potential resources. In this way one can focus on narrowing the relevant parameter uncertainties causing the largest contributions without the need to spend time and effort in addressing other parameter uncertainties that would help but little, if at all, without the main focus on the important contributors to uncertainty of the mean resource assessment.
Production from Multiple Horizons: Budget Constraints and Minimum Involvement
Authors: Lerche I.
Published: April 2004

For a given oilfield in which a company can invest to drill untapped horizons for profit, the influences of value, cost, success probability and corporate risk tolerance provide an optimal working interest that should be taken in the opportunity in order to maximize the risk adjusted value. When several horizons are available, but when the total budget is insufficient to take optimal working interest in each, an analytic procedure is given for optimizing the risk adjusted value of the total portfolio; the relevant working interests are also derived based on a cost exposure constraint. Several numerical illustrations exhibit use of the method under different budget conditions, and with different numbers of available horizons. The result is that the computations of portfolio balancing can be done quickly utilizing the analytical expressions presented here, thereby providing rapid assessments of undrilled horizons and their worth.
Environmental Issues Relating to Greenhouse Carbon Dioxide Emissions in the World
Authors: Balat Mustafa , Balat Havva , Acici Neslihan
Published: April 2004

Emissions of CO2 caused by human activity are generally considered the most important single source of potential future warming. States have played a leading role in protecting the environment by reducing emission of greenhouse gases (GHGs). State emissions are significant on a global scale. CO2 and CO are main GHGs associated with global warning. At the present time, coal is responsible for 30–40% of the world CO2 emissions from fossil fuels. Carbon assessments can play an important role in a strategy to control carbon dioxide emissions while raising revenue.
Current Advances in Alternative Motor Fuels
Authors: Demirbas Ayhan
Published: April 2004

The most popular alternative motor fuels are bioethanol, biodiesel, hydrogen and boron. There are also interests in methyl and ethyl alcohols, natural gas, liquefied petroleum gas, p-series, electricity, and solar fuels were concluded as alternative engine fuels. Alternative engine fuels are fuels competitive to petroleum. These fuels are important because they replace petroleum fuels. There are many benefits the environment, economy and consumers in using alternative fuels. There are also dependencies on production and lifting costs but these are not considered in detail here.
Moving Loads and Car Disc Brake Squeal
Authors: Ouyang Huajiang
Published: April 2004

Disc brake vibration and squeal is a source of irritation and distraction. A squealing brake gives customers the impression of underlying quality problems of the vehicle. The warranty cost due to disc brake noise is very high and has led to much research and investment in tackling disc brake vibration and noise. Brake squeal is friction-induced vibration of immense complexity. Research in recent years has resulted in quieter brakes. However disc brake squeal still occurs frequently. Modelling disc brake systems and simulating their dynamic behaviour is an efficient and cost-effective way of correcting squealing brakes and creating new designs for improved noise performance. This paper describes the methodology for simulating disc brake vibration and predicting disc brake squeal established by the author's research group and presents numerical results against experimental results. This approach is centred on the moving-load concept. It offers a new angle in tackling the difficult disc brake squeal problem and has shown much promise.
Rent-Seeking and Grandfathering: The Case of GHG Trade in the Eu
Authors: Brandt Urs Steiner , Svendsen Gert Tinggaard
Published: April 2004

The EU Commission has recently proposed a new directive establishing a framework for greenhouse gas (GHG) emissions trading within the European Union. The idea is to devalue part of the emission quotas in circulation by the year 2012 at latest, so that the EU will meet its Kyoto target level of an 8% GHG reduction. Our main question is whether the final choice of allocation rule can be explained by the role of industrial groups in the policy making process. We answer this question by using rent-seeking theory and by analysing the Green Paper hearing replies from the main industrial groups. In other words, we want to explain and observe how rent-seeking (or lobbyism) affects the design of environmental regulation and energy policy in favour of well-organized industrial interest groups. We argue that some firms are likely to reap a net gain from being regulated by a grandfathered emission trading system. This is so because total costs of emission reduction and lobbyism are likely to be smaller than the total rents from having this type of regulation.
The Renewable Portfolio Standard in Western Australia — Performance in the Face of Institutional Constraints
Authors: Weiter Chloe
Published: April 2004

The Renewable Portfolio Standard (RPS) is a popular method of increasing the portion of renewable energy generation in electricity supplies. The Australian Federal Government introduced a RPS that, in addition to accelerating the uptake of renewable energy, is designed to provide an ongoing base for the development of commercially competitive renewable energy and contribute to the development of an internationally competitive renewable energy industry. The design parameters of the RPS and the existing electricity market framework within which it operates are important considerations in determining the success of this policy initiative in meeting all its objectives. On the basis of the Western Australian experience, this paper argues that while conceptually the RPS may be a useful tool for increasing the portion of electricity generated by renewable resources, and supporting the development of a competitive renewable energy industry, its effectiveness depends upon the policy framework within which it operates.
The Influence of Climate Change on Energy Production & Heating Energy Demand in Finland
Authors: Venäläinen Ari , Tammelin Bengt , Tuomenvirta Heikki , Jylhä Kirsti , Koskela Jarkko , Turunen Merja A. , Vehviläinen Bertel , Forsius John , Järvinen Pekka
Published: April 2004

In this study we have examined how the anticipated anthropogenic climate change will affect the heating power demand of buildings, hydropower production, the climatological potential of peat production, bioenergy, and wind energy. The study concentrates on conditions in Finland and the future period studied was 2021–2050. The future climate conditions were primarily taken from simulations by the Hadley Centre's global climate model, HadCM3. According to the climate scenarios used in this study, the heating energy demand for the period 2021–2050 will decrease on average by some 10 % from the period 1961–1990. At the same time hydropower production will increase by 7–11 %, the climatological potential of peat production by 17–24 %, the climatological potential of biomass (mainly wood) by 10–15 % and the climatological potential of wind power by 2–10 %. These results must still be considered as preliminary, mainly because there are still large uncertainties related to the estimation of the magnitude of climate change.
The Role of Viscosity in Aerodynamic Sound Generation
Authors: Morfey C.L.
Published: April 2004

The interpretation of unsteady surface shear stresses as dipole sound sources is discussed. Provided ωv/c2 « 1, it is legitimate to calculate the radiated pressure using viscous surface dipoles in combination with an inviscid-medium Green function. This is demonstrated via comparisons of acoustic-analogy predictions with exact solutions, for two plane-boundary problems. A Green function that is tailored to the linear relation between pressure and normal velocity on the boundary, as used by Powell [ J. Acoust. Soc. Am. Vol. 32, 1960, pp. 982–990], highlights the role of viscous stresses in aeroacoustic calculations.
The Source of Aerodynamic Noise
Authors: Lilley Geoffrey M.
Published: April 2004

This paper is a tribute to Alan Powell's achievements and his extensive publications in hydro and aeroacoustics.1 The theory of Aerodynamic Noise was established by Sir James Lighthill in 1952. The beauty of Lighthill's treatment was that he based this theory on the exact Navier-Stokes equations and showed, by their rearrangement, how the source of aerodynamic noise could be obtained from exact time-accurate calculations or experiment. Lighthill used the emission or propagation theory whereby an observer in a uniform medium at rest receives acoustic radiation from a distribution of moving sources of sound. Their properties are found using an acoustic analogy. The relevant fluctuations in a turbulent fluid flow can be expressed in terms of Lighthill's stress tensor Tij, which is used to define a distribution of equivalent acoustic sources, which move through an otherwise uniform stationary fluid. An alternative procedure is to concentrate on the acoustic generation and to regard the sources of sound at rest or in motion in a uniform medium moving at a constant speed. (The approach can be extended to consider any arbitrary mean fluid motion.) The advantage of the present approach, involving the convective wave equation is that flow-acoustic interaction becomes part of the solution. In Lighthill's theory, flow-acoustic interaction is either ignored or at best is included as an equivalent source. The purpose of the present paper is to show there is no unique source of aerodynamic noise for it depends on the flow quantity used to describe the radiated sound. The convective wave equation is introduced and shown to involve similar sources to those found by Lighthill for the wave equation in a medium at rest. The source function found for the convective wave equation for a turbulent flow is shown to involve a modified Lighthill's stress tensor, which is non-linear in velocity and temperature fluctuations. It is further shown when the rate of dilatation covariance is examined, which can be derived from Lighthill's solution, that this small quantity, which Lighthill so carefully treated in retaining the exact properties of the compressible flow, is itself directly responsible for the rate of change of volume in the fluid and the creation of the noise which is radiated from the turbulent flow.
Acoustic Streaming: From Rayleigh to Today
Authors: Boluriaan Said , Morris Philip J.
Published: April 2004

This paper reviews the current state of knowledge of several classes of acoustic streaming. Acoustic streaming is classified based on the different mechanisms by which it is generated. For each category, the main achievements in terms of analysis, experimental work, and numerical simulation are described. An order of magnitude analysis, applicable to all types of acoustic streaming, is also given. This provides an additional means to classify acoustic streaming as either slow or fast, depending on the amplitude of the primary driving mechanism. The significant lack of understanding in the general area of fast streaming is noted, and the importance of the use of direct numerical simulations in the study of nonlinear streaming is emphasized. The paper concludes with a summary of the many challenges that are still faced by researchers in this field. The authors are pleased to contribute this paper in honor of Alan Powell's significant contributions to acoustics on the occasion of his eightieth birthday.
Acoustic and Mean Flow Measurements of High-Speed, Helium-Air Mixture Jets
Authors: Doty Michael J. , McLaughlin Dennis K.
Published: April 2004

The effectiveness of using helium-air mixture jets to simulate heated jets at both subsonic and supersonic velocities is investigated. Particular emphasis is placed on replicating the aeroacoustic properties of heated jets. Acoustic directivity and spectral measurements of helium-air mixture jets are compared to existing heated jet data. Results typically indicate agreement within 2 dB with some discrepancy attributable to facility and run condition differences. In addition, mean flowfield measurements indicate a shortening of the potential core and a slight decrease in jet spreading with the addition of helium – the same trends observed for heated jets. The similarities in acoustic and mean flow behavior indicate that helium-air mixture jet experiments provide a viable low-cost alternative to heated jet experiments.
Über einige lokal verallgemeinernde Speicher und ihre Weiterentwicklung, Teil 2: Delaunay Triangulation (One some Locally Generalizing Storage Methods and their further Development, Part 2: Delaunay Triangulation)
Authors: Tolle Henning
Published: April 2004

Bei der Modellierung, Steuerung und Regelung nichtlinearer Prozesse werden häufig zwei- bzw. mehrdimensionale Kennfelder eingesetzt. Sie können äußerst effektiv in lokal verallgemeinernden Speichern abgelegt werden. Der Beitrag stellt an Hand von drei Beispielen und ihren Weiterentwicklungen dar, dass sehr verschiedenartige Ansätze möglich sind und die Auswahl gemäß ihren inherenten Vor- und Nachteilen von der ins Auge gefassten Anwendung bestimmt werden sollte. Teil II behandelt als dritten Ansatz eine Methode, die von einer mathematischen Darstellung beliebig geformter Flächen im Raum inspiriert wurde und fasst die Aussagen der beiden Teile des Aufsatzes zusammen.
Die virtuelle Lernumgebung SMARTFRAME – Kodierung und didaktische Aufbereitung von Lernmaterialien durch Lernobjekte (The Virtual Learning Environment SMARTFRAME)
Authors: Reiners Torsten , Reiß Dirk , Sassen Imke , Voß Stefan
Published: April 2004

Die Darstellung von Lernmaterialien erfolgt in den meisten Fällen durch statische, mit interaktiven Applets aufgewertete HTML-Seiten. Ein ganzheitliches Lernerlebnis mit individueller Adaptivität wird mit dieser einfachen Kodierung von Lernmaterialien allerdings nur in einem stark eingeschränkten Sinne ermöglicht. Erst durch eine verstärkte Einbindung von interaktiven Lernelementen in Kombination mit dynamisch generierten Seiten und einer individuellen Adaption der Lernumgebung an den jeweilig Lernenden kann echter Mehrwert im Sinne weitergehender didaktischer Unterstützung erzielt werden. Zunächst präsentieren wir die mediendidaktische Konzeption und Umsetzung der virtuellen Lernumgebung SMARTFRAME (www.smartframe.de). Aus konzeptioneller Sichtweise soll aufgezeigt werden, wie eine ganzheitliche Adaption der Lernumgebung an individuelle Lernprozesse erreicht werden kann, die über die bereits übliche Interaktivität einzelner Lernmodule und benutzerspezifischer Eingangskonfigurationen hinausgeht. Im Anschluss wird schematisch die technische Realisierung des Transformationsprozesses der XML-kodierten Lernobjekte beschrieben, der sich durch eine dynamische – d.h. beim Abruf der Inhalte – lernerspezifische Adaptivität der Lernmaterialien in Bezug auf deren Zusammensetzung und Präsentation auszeichnet.
Praxisgemeinschaft als didaktische Konzeption: Neue Ansätze medienunterstützter Projektarbeit in der angewandten Informatik (Communities of Practice as Didactical Concept: New Approaches for Media-Supported Project Work in Applied Computer Science Teaching)
Authors: Rohde Markus , Jarke Matthias , Klamma Ralf , Wulf Volker
Published: April 2004

Im vorliegenden Beitrag werden die Erfahrungen mit einer praxisorientierten Lehrveranstaltung im Informatikstudium an der RWTH Aachen vorgestellt. Im Rahmen der kombinierten Veranstaltung „Entrepreneurship and New Media” wurde neben einem Projektpraktikum eine begleitende Vorlesungsreihe mit externen Dozenten angeboten. In Projektgruppen bearbeiteten die Studierenden Praxisaufgaben, die von zwei Start-Up Unternehmen gestellt und betreut wurden. Die Studierenden wurden dabei miteinander und mit ihren verschiedenen Betreuern durch ein Community-System vernetzt. Es werden die Konzeption und der lerntheoretische Hintergrund der Lehrveranstaltung dargestellt. Außerdem werden die Ergebnisse einer Studie präsentiert, die die didaktische Grundkonzeption und die Nutzung des Community-Systems evaluierte. Abschließend wird die Bedeutung von Praxisgemeinschaften für die Lehre der angewandten Informatik diskutiert.
Rechnergestützte Brettspiele für die Erlebniswelten der Zukunft (Computer Augmented Tabletop Games for the Experience Worlds of the Future)
Authors: Magerkurth Carsten , Stenzel Richard
Published: April 2004

In diesem Beitrag wird STARS, eine Plattform zur Realisierung rechnergestützter Brettspiele, vorgestellt. Mit STARS lassen sich hybride Brettspielsysteme entwickeln, die die spielerische Interaktion zwischen Menschen durch den Einsatz von Informationstechnologie unterstützen. Neben der Beschreibung der Hard- und Softwarekomponenten sowie des Interaktionsdesigns werden exemplarisch realisierte Spiele vorgestellt und von ersten Erfahrungen mit der STARS-Plattform berichtet. Bei dem vorliegenden Artikel handelt es sich um eine aktualisierte und erweiterte Version des Beitrags auf der Mensch und Computer 2003-Tagung, der den ersten Platz im Wettbewerb um den Best-Paper-Award gewinnen konnte.
Monitoring prenatal alcohol exposure
Authors: Floyd R. Louise , Sidhu Jasjeet S.
Published: April 2004

Alcohol use during pregnancy is a leading, preventable cause of birth defects and developmental disabilities in the United States, with fetal alcohol syndrome (FAS) being one of the most severe outcomes. Current survey statistics find that approximately one in eight pregnant women (500,000 per year) report alcohol use, with approximately 80,000 reporting binge drinking. While annual rates have fluctuated, trends analysis finds that there has been no significant change in rates of prenatal alcohol exposure over the past 10‐year period. Development of effective programs to prevent FAS and to monitor the success of prevention efforts requires epidemiological data systems to inform these activities. This article describes alcohol use patterns among childbearing‐age women and data sources that can be used in monitoring this behavior. Published 2004 Wiley‐Liss, Inc.
Fetal, infant, and child mortality in a context of alcohol use
Authors: Burd Larry , Wilson Harry
Published: April 2004

Alcohol is an important element in the causal chain of risk for fetal, infant, and childhood mortality. Mortality risk is influenced by interactions of alcohol with other environmental and genetic factors and temporal periods of susceptibility. In this paper we discuss four time periods (preconceptual, gestational, infancy, and childhood) where alcohol use may create a context of risk. Alcohol use in one period increases the risk of alcohol use in subsequent periods. Gestational alcohol use can influence risk of mortality from abuse of mother/fetus, can cause other adverse outcomes, and can result in fetal alcohol spectrum disorders (FASDs). In infancy alcohol use can increase risk from impairment of arousal in adults who use alcohol. Infants with gestational exposure can be behaviorally difficult with sleep disturbance, irritability, and colic. This can increase the risk of harm or death, especially during periods of caretakers' alcohol use. Caretakers' alcohol use and smoking are strongly correlated. The all‐cause mortality rate in people diagnosed with fetal alcohol syndrome (FAS) is over 5%. All‐cause mortality in siblings of diagnosed cases of FAS is increased 530% compared to siblings of matched controls. We recommend that a context of alcohol use be considered as a marker for multifactorial risk in all fetal, infant, and child deaths. A schema to collect data on alcohol use is provided to increase awareness of alcohol use as an environmental risk marker for mortality. © 2004 Wiley‐Liss, Inc.
Medieval trabecular bone architecture: The influence of age, sex, and lifestyle
Authors: Agarwal S.C. , Dumitriu M. , Tomlinson G.A. , Grynpas M.D.
Published: April 2004

Osteoporosis has become a growing health concern in developed countries and an extensive area of research in skeletal biology. Despite numerous paleopathological studies of bone mass, few studies have measured bone quality in past populations. In order to examine age‐ and sex‐related changes in one aspect of bone quality in the past, a study was made of trabecular bone architecture in a British medieval skeletal sample. X‐ray images of 5‐mm‐thick coronal lumbar vertebral bone sections were taken from a total of 54 adult individuals divided into three age categories (18–29, 30–49, and 50+ years), and examined using image analysis to evaluate parameters related to trabecular bone structure and connectivity. Significant age‐related changes in trabecular bone structure (trabecular bone volume (BV/TV), trabecular number (Tb.N), trabecular separation (Tb.Sp), and anisotropic ratio (Tb.An)) were observed to occur primarily by middle age with significant differences between the youngest and two older age groups. Neither sex showed continuing change in trabecular structure between the middle and old age groups. Age‐related changes in bone connectivity (number of nodes (N.Nd) and node‐to‐node strut length (Nd.Nd)) similarly indicated a change in bone connectivity only between the youngest and two older age groups. However, females showed no statistical differences among the age groups in bone connectivity. These patterns of trabecular bone loss and fragility contrast with those generally found in modern populations that typically report continuing loss of bone structure and connectivity between middle and old age, and suggest greater loss in females. The patterns of bone loss in the archaeological samples must be interpreted cautiously. We speculate that while nutritional factors may have initiated some bone loss in both sexes, physical activity could have conserved bone architecture in old age in both sexes, and reproductive factors such as high parity and extended periods of lactation could have played a key role in female bone maintenance in this historic population. The study of qualitative elements (such as trabecular architecture) is vital if we are to understand bone maintenance and fragility in the past. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Eyasi 1 and the suprainiac fossa
Authors: Trinkaus Erik
Published: April 2004

A reexamination of Eyasi 1, a later Middle Pleistocene east African neurocranium, reveals the presence of a suite of midoccipital features, including a modest nuchal torus that is limited to the middle half of the bone, the absence of an external occipital protuberance, and a distinct transversely oval suprainiac fossa. These features, and especially the suprainiac fossa, were considered to be uniquely derived for the European and western Asian Neandertals. These observations therefore indicate that these features are not limited to Neandertal lineage specimens, and should be assessed in terms of frequency distributions among later archaic humans. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Mitochondrial phylogeny and systematics of baboons (Papio)
Authors: Newman Timothy K. , Jolly Clifford J. , Rogers Jeffrey
Published: April 2004

Baboons (Papio, s.s.) comprise a series of parapatric allotaxa (subspecies or closely related species) widely distributed in sub‐Saharan Africa. Despite extensive studies of their ecology, morphology, and behavior, disagreement about their phylogenetic relationships continues, as expressed in the current coexistence of at least three major, competing taxonomic treatments. To help resolve this situation, we sequenced ∼900 bases of mitochondrial DNA of 40 individuals from five of the widely recognized “major” allotaxa. Total sequence diversity (>5%) is high compared to most primate species. Major mitochondrial clades correspond to recognized allotaxa, with the important exception that haplotypes from yellow and olive baboons form a single, monophyletic clade within which the two allotaxa do not comprise mutually exclusive clusters. The major clades fall unambiguously into the pattern: (chacma (Guinea (hamadryas (yellow + olive)))). This phylogeny does not support taxonomies that oppose hamadryas to all other baboons (“desert” vs. “savanna”), but is compatible with the view that all definable allotaxa should be recognized as coordinates, either as “phylogenetic” species or “biological” subspecies. The close relationship and unsegregated distribution of haplotypes from Kenyan and Tanzanian yellow and olive baboons are unexplained, but may reflect introgression across the documented hybrid zone. The overall phylogeny, when combined with paleontological data, suggests a southern African origin for extantPapiobaboons, with all extant lineages sharing a common mitochondrial ancestor at approximately 1.8 Ma. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Oligonucleotide synthesis onto poly(N‐acryloylmorpholine‐co‐N‐acryloxysuccinimide): Assessment of the resulting conjugates in a DNA sandwich hybridization test
Authors: Minard‐Basquin Claire , Chaix Carole , D'Agosto Franck , Charreyre Marie‐Thérèse , Pichot Christian
Published: April 2004

A water‐soluble statistical poly(N‐acryloylmorpholine‐co‐N‐acryloxysuccinimide) [poly(NAM/NAS)] copolymer was studied for polymer–oligonucleotide (ODN) conjugate elaboration and for further use in diagnostic applications. Three different copolymers were first prepared by free‐radical solution polymerization with different N‐acryloylmorpholine (NAM) and N‐acryloxysuccinimide (NAS) molar ratios (80/20, 70/30, and 60/40). Their number‐average molecular weights ranged from 98,000 to 120,000 g/mol, as determined by aqueous size exclusion chromatography with an online light‐scattering detector. Then, polymer–ODN conjugates were obtained via a strategy consisting of the direct synthesis of ODNs onto polymer chains previously grafted onto a controlled pore glass support. Before the grafting of the polymer onto the solid support, a preliminary step was performed to bind a nucleotide starter along the polymer chain (via the reactive NAS units) to initiate automated DNA synthesis. To multiply the number of ODNs growing from starters, a branched phosphoramidite synthon [bearing two O‐dimethoxytrityl groups] was introduced at the first step of ODN elongation as a short sequence of four branched synthons alternated with three thymidine residues. Conjugates were assessed in a DNA sandwich hybridization test developed for hepatitis B virus detection. Sensitivity limits were evaluated and compared to those obtained with an other polymer, poly(maleic anhydride‐alt‐methyl vinyl ether) [poly(MA/MVE)]. A sensitivity limit of 2.6 × 107 DNA copies/mL was reached with the poly(MA/MVE)–ODN conjugate at the capture phase and with the poly(NAM/NAS)–branched ODN conjugate at the detection phase of the test. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3784–3795, 2004
Effect of polyvinylpyrrolidone on morphology and performance of hemodialysis membranes prepared from polyether sulfone
Authors: Barzin J. , Madaeni S. S. , Mirzadeh H. , Mehrabzadeh M.
Published: April 2004

Flat‐sheet hemodialysis membranes were prepared by phase inversion technique using polyether sulfone (PES) dissolved in dimethylacetamide (DMAc) with and without the addition of polyvinylpyrrolidone (PVP). The effect of the composition of the casting solution on membrane morphology and performance were investigated. The performances of membranes were elucidated on the basis of removal of uremic toxins (urea, uric acid, and creatinine) from human blood serum. The membrane prepared from 12 wt % PES with 2.8 wt % PVP demonstrated better performance compared to the other compositions. The membrane performance is a consequence of membrane morphology. Membranes with channel‐like or long finger‐like structures provide superior removal efficiencies. If the morphology turns to a sponge structure, the effectiveness is diminished. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3804–3813, 2004
Hydrolytic aging of polypropylene studied by X‐ray photoelectron spectroscopy
Authors: Massey S. , Adnot A. , Roy D.
Published: April 2004

X‐ray photoelectron spectroscopy (XPS) was used to study the hydrolytic aging of polypropylene according to the pHs of degrading buffer solutions and the time of aging. The study was concentrated over periods of 3, 6, and 9 months for values of pH close to the real environments of use of the material (pH of 6, 7, and 8). The polypropylene underwent an oxidation of its polymeric matrix, independently of the range of pH values, by the production of COH, CO, and OCO groups. These chemical functions were observed in high resolution XPS spectra around C1sand O1speaks. Beginning with these results and from mechanisms of (photochemical, thermal, and others) aging proposed in the literature, it was then possible to propose mechanisms of hydrolytic ageing of polypropylene. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3830–3838, 2004
Adhesion mechanisms in the solid‐state bonding technique using submicrometer aromatic thermosetting copolyester adhesive
Authors: Xu Kun , Selby John C. , Shannon Mark A. , Economy James
Published: April 2004

The adhesion mechanism between polyimides and aromatic thermosetting copolyester (ATSP) involved in the solid‐state bonding technique using submicrometer ATSP coatings was evaluated. The adhesion strength at the interface between ATSP and polyimide is strongly related to the diffusion of ATSP into the polyimide base layer. We used dynamic secondary ion mass spectrometry to study the interface width between deuterated ATSP and polyimides and found that the interface between ATSP and poly(4,4′‐diphenylether pyromellitimide) (PMDA‐ODA) is wider than the interface between ATSP and poly(p‐phenylene biphenyltetracarboximide) (BPDA‐PPD) because of the less rigid chain in the PMDA‐ODA. By partially curing both polyimides, the interface width was greatly increased, which could lead to an improved adhesion at the interface between polyimide BPDA‐PPD and ATSP. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3843–3856, 2004
Mechanical properties and biodegradability of green composites based on biodegradable polyesters and lyocell fabric
Authors: Shibata Mitsuhiro , Oyamada Shingo , Kobayashi Shin‐ichi , Yaginuma Daisuke
Published: April 2004

Green composites composed of regenerated cellulose (lyocell) fabric and biodegradable polyesters [poly(3‐hydroxybutyrate‐co‐3‐hydroxyvarelate) (PHBV), poly(butylene succinate) (PBS), and poly(lactic acid) (PLA)] were prepared by compression‐molding method. The tensile moduli and strength of all the biodegradable polyester/lyocell composites increased with increasing fiber content. When the obtained PLA/lyocell composites were annealed at 100°C for 3 h, the tensile strength and moduli were lowered despite the increase of degree of crystallization of the PLA component. The SEM observation of the composites revealed that the surface of the annealed composite has many cracks caused by the shrinkage of the PLA adhered to lyocell fabric. Multilayered PLA/lyocell laminate composites showed considerably higher Izod impact strength than PLA. As a result of the soil viral test, although the order of higher weight loss for the single substance was lyocell > PHBV > PBS > PLA, the biodegradability of the green composites did not reflect the order of a single substance because of the structural defect of the composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3857–3863, 2004
Preparation, properties, and mathematical modeling of microparticle drug delivery systems based on biodegradable amphiphilic triblock copolymers
Authors: Yan Guo‐Ping , Li Hua , Cheng Si‐Xue , Bottle Steven E. , Wang Xiao‐Gui , Yew Yong Kin , Zhuo Ren‐Xi
Published: April 2004

A series of biodegradable amphiphilic A‐B‐A type triblock copolymers P(BLA‐PEG‐BLA), composed of hydrophilic poly(ethylene glycol) (PEG) as a middle block component (B) and hydrophobic poly(β‐benzyl‐L‐aspartate) as outer polypeptide block components (A), were synthesized by copolymerization of β‐benzyl‐L‐aspartate N‐carboxy anhydride (BLA‐NCA) and the diaminated PEG with the primary amino groups capped at both ends. These P(BLA‐PEG‐BLA) copolymers were characterized by 1H‐NMR, DSC, and GPC. The triblock copolymers were used to prepare three kinds of drug delivery systems including Norfloxacin (INN)‐incorporated P(BLA‐PEG‐BLA) microparticles and tablets. The morphologies of the microparticles were characterized by SEM. The in vitro release properties of the microparticles and tablets in PBS were also evaluated. A mathematical model, which incorporates a linear first‐order dissolution term and the transient Fickian diffusion equation, was developed to account for the kinetics of drug release from the INN‐incorporated P(BLA‐PEG‐BLA) microparticles. The results indicated that the overall release process was well controlled by both drug dissolution and diffusion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3869–3873, 2004
Removal of Cu(II) from aqueous solutions by chelating starch derivatives
Authors: Li Yi Jiu , Xiang Bo , Ni Ya Ming
Published: April 2004

Two chemically modified starch derivatives, crosslinked amino starch (CAS) and dithiocarbamates modified starch (DTCS), were prepared and used for the removal of Cu(II) from aqueous solutions. CAS was found to be effective for the adsorption of Cu(II), which tended to form a stable amine complex. Adsorption of Cu(II) onto DTCS was higher than that onto CAS. Experiments showed that the adsorption processes of Cu(II) on both CAS and DTCS were endothermic, and followed Freundlich isothermal adsorption. For both adsorbents, dynamic modeling of their adsorption showed that the first‐order reversible kinetic model described the adsorption process. The adsorption rate constants of CAS and DTCS were 1.578 and 10.32 h−1, respectively. From the results of the thermodynamic analysis, free energy ΔG, enthalpy ΔH, and entropy ΔS of the adsorption process were calculated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3881–3885, 2004
Study on processing of ultrahigh molecular weight polyethylene/polypropylene blends: Capillary flow properties and microstructure
Authors: Liu Gongde , Chen Yingzi , Li Huilin
Published: April 2004

The capillary flow properties and morphologies of ultrahigh molecular weight polyethylene/polypropylene (UHMWPE/PP) blends were studied. The results show that UHMWPE is difficult to process. The melts flowed unsteadily at lower shear rate. With 10 wt % PP contained in the UHMWPE/PP blends, the apparent melt viscosity was much lower than that of UHMWPE. When the PP content increased to 20 and 30 wt %, no pressure vibration occurred throughout the whole shear rate range. Microstructure analysis showed that PP prefers to locate in the amorphous or low crystallinity zones of the UHMWPE matrix. The flowability of UHMWPE increased substantially with the addition of PP. The addition of PE could not effectively reduce the chain entanglement density of UHMWPE. The improvement of processability of UHMWPE by the addition of PE was rather limited. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3894–3900, 2004
Interlayer delamination and adhesion of coextruded films
Authors: Zhou Hongyi
Published: April 2004

Efforts to evaluate interlayer adhesion of coextruded films are often hampered by the inability to initiate delamination. On the other hand, interlayer delamination was often noticed at cut or trimmed edges of coextruded films. In this study, a test method was developed by first initiating delamination by uniaxial stretching and then measuring interlayer adhesion by peel test. Delamination was initiated by uniaxial stretching under controlled conditions for samples with double‐neck geometry. The double‐neck geometry was designed to create a specimen for the subsequent 180° peel test. Peel force was used to quantify interlayer adhesion of coextruded films based on polycarbonate and its copolymers. With this two‐step technique, coextruded films with peel force as high as 5300 N/m or 30 lb./in. were quantified. In addition, effects of copolymer composition and coextrusion processing condition on interlayer adhesion of these coextruded films were clearly demonstrated. A great deal of variation of interlayer adhesion across film surface was also revealed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3901–3909, 2004