bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Quality Modeling
Authors: McCutcheon Steven C
Published: April 2006

Water quality forecasts are vital to determining limitations for point source waste loads and diffuse or nonpoint source loads required to meet water quality standards in streams, lakes, and estuaries. Only mechanistic water quality modeling is widely applicable for forecasting. Although surface water quality modeling has a sound interdisciplinary scientific basis, the use of these analysis tools are limited in regulatory and resource decision making by a lack of a professional consensus defining model application protocols. To analyze water quality problems, (i) the uses for a water body must be evaluated, (ii) models must be calibrated and tested to relate impaired water quality to the waste sources, (iii) a formal uncertainty analysis must define a margin of safety to protect human and ecological health, and (iv) when necessary, an economic analysis must be performed to determine if the designated uses are reasonably achievable.
Terrestrial Ecosystems
Authors: Tague Christina L , Band Lawrence E , Franklin Janet
Published: April 2006

The science of ecohydrology centers on understanding the linkages and feedbacks between terrestrial ecosystems and the hydrologic cycle. Within the disciplines of hydrology, ecosystem ecology, and community ecology, a wide range of conceptual, mathematical, and field‐based approaches have evolved to address specific ecohydrologic research questions. In this article, we discuss key elements of these ecohydrologic approaches. We begin by focusing on conceptual frameworks that are organized at the patch level, which define spatially homogeneous units. We compare a set of models in terms of the specific hydrologic and ecologic processes considered and the degree of coupling between them. We then address issues of landscape heterogeneity and compare approaches to the resolution of spatial patterns of soil, topography, vegetation, and atmospheric conditions and the representation of the interactions and feedbacks between neighboring patches. The hierarchical structure and function of terrestrial ecohydrologic systems involve processes varying over very different time and space scales. Finally, we discuss challenges and next steps in developing an integrated framework that can address the range of spatial and temporal scales implied by hydrologic feedbacks on both shorter‐term ecosystem material and energy cycling and longer‐term ecosystem structure and evolution.
Subsurface Stormflow
Authors: Weiler Markus , McDonnell Jeffrey J , Tromp‐van Meerveld Ilja , Uchida Taro
Published: April 2006

Subsurface stormflow is a runoff producing mechanism operating in most upland terrains. In a humid environment and steep terrain with conductive soils, subsurface stormflow may be the main mechanism of storm runoff generation. In drier climates and in lowlands with gentler topography, subsurface stormflow may occur only under certain extreme conditions (high antecedent soil moisture), when transient water tables form and induce lateral flow to the channel. While an important contributor to the volume of flow in the stream, subsurface stormflow is also responsible for the transport of labile nutrients into surface water bodies. Since the flow path of water in the subsurface often determines the chemistry of waters discharging into the stream and hence the water quality, characterizing this subsurface flow path and the water's age and origin is important. Subsurface stormflow may also enhance positive pore pressure development in steep terrain and may be responsible for landslide initiation. Thus, subsurface stormflow is of great interest and importance beyond the conventional hydrological literature. This article examines the history of the study of subsurface stormflow processes, reviews theories on the generation of subsurface stormflow, and gives a detailed overview of current research in subsurface flow processes and the implication for future research.
Flood Routing and Inundation Prediction
Authors: Bates Paul D
Published: April 2006

This contribution considers the methods available to hydrologists to simulate flow routing and inundation in natural channels. Whilst the fluid dynamics of free surface flow in rivers and over floodplains may be complex, the methods available to treat such problems range widely in complexity from simple empirical models to full solutions of three‐dimensional Navier–Stokes equations with sophisticated representations of flow turbulence. These methods are reviewed in detail, followed by a consideration of their requirements for topography, friction, initial condition, boundary condition, and validation data. In particular, the contribution discusses how these needs are being met increasingly using remote sensing techniques. Lastly, the contribution considers techniques to evaluate uncertainties in flow modeling.
Aquifer Characterization by Geophysical Methods
Authors: Vereecken Harry , Kemna Andreas , Münch Hans‐Martin , Tillmann Axel , Verweerd Arre
Published: April 2006

Geophysical methods are increasingly being used to characterize the subsurface. They offer the potential to derive basic characteristics, state variables, and properties of geological formations. In this article, we focus on the application of geophysical methods to derive properties and state variables of aquifer systems. Special attention is given to the assessment of hydraulic conductivity, porosity, and water saturation. Three different groups of methods (seismics, electrical techniques, and electromagnetics) and their combined use are discussed. For each method, relationships between geophysical and hydrogeological quantities are outlined and applications are presented. A separate section is devoted to the development and application of combined approaches in hydrogeophysics.
Hydrology of Snowcovered Basins
Authors: Davison Bruce , Pietroniro Alain
Published: April 2006

Snowcovered catchments are an integral part of the earth's physical, chemical, and biological regulatory processes. Catchment‐based assessments of snow are typically derived from snow surveys and snow courses. Remote sensing is also a valuable tool for use in understanding the nature and distribution of snowcover in a catchment. Snowcovered basin classifications are founded on the source and timing of runoff and the characteristics of the snow. In order to understand the hydrology of snowcovered catchments, it is important to understand the physics of snowmelt and other related phenomena, such as canopy effects that influence the temporal and spatial distribution of snow within a catchment, including both the energy and mass balance components. Operational temperature index models for basin snowmelt and statistical models for horizontal snowcover distribution help approximate some of the physical processes that are not (or cannot be) directly measured. Hydrological models are an attempt to articulate an understanding of the complex and nonlinear interactions within the hydrological cycle using a rational mathematical approach such as an index method or the energy balance approach. A number of projects have been completed or are underway to compare these models. Hydrological applications, avalanche forecasting, weather forecasting, and climate modeling have all driven snow research, with much cross fertilization between these fields.
Surface and Englacial Drainage of Glaciers and Ice Sheets
Authors: Nienow Peter , Hubbard Bryn
Published: April 2006

Supraglacial drainage occurs wherever snowpack, firn, or ice at the glacier surface is at the pressure melting point and supplied with additional energy, thereby generating melt water. Energy sources vary, but net radiation is usually the dominant source, although inputs of rainwater can also provide large volumes of surface runoff. The surface melt water is routed through the snowpack, firn, and across the glacier surface according to the local hydraulic gradient. In general, routing of water through snow and firn is slow (10−4–10−5 m s−1), contributing to a significant lag between melt water production and runoff at the glacier snout, whereas flow across exposed ice surfaces is typically 3–5 orders of magnitude faster. Under certain conditions where parts of the snowpack, firn, and/or ice surface are below the pressure melting point, the melt water will refreeze. Otherwise, the melt water will be routed supraglacially to the glacier margin unless intersected by a pathway from the glacier surface to the glacier interior. Such pathways include crevasses and moulins, and in temperate glaciers, microscale englacial veins. Flow rates through the englacial system vary considerably according to the hydraulic efficiency of the route taken. The routing of melt waters through both supraglacial and englacial drainage systems therefore affects the runoff response of an ice mass to rain and melt water inputs. During the course of a melt season, the efficiency of routing through both systems evolves, thereby altering the runoff response time to input variations.
Hydrology of Glacierized Basins
Authors: Willis Ian
Published: April 2006

The presence of snow and ice and the lack of vegetation and soil make the hydrology of glacierized basins very different to that of equivalent nonglacierized basins. This article discusses how the characteristics of glacierized basins control their runoff regime and its interannual, intraannual, and intraseasonal variability. The magnitudes and patterns of seasonal water storage and release associated with the snowpack, firn layers, and englacial and subglacial drainage systems are also considered. The controls on flooding in glacierized catchments are discussed with specific reference to the catastrophic drainage of ice‐dammed subglacial and ice‐marginal lakes, moraine‐dammed proglacial lakes, and drainage of water from the englacial/subglacial drainage network that may be triggered by high surface melting or rainstorms. Finally, the effects of climate change on runoff regimes, water storage, and floods are assessed. The similarities and differences between the hydrological regimes of mid‐, high‐, and low‐latitude basins containing glaciers with different thermal regimes are highlighted.
Sediment and Solute Transport in Glacial Meltwater Streams
Authors: Tranter Martyn
Published: April 2006

This review documents the suspended sediment and major ion concentrations of glacial runoff, with a view to understanding the controls on sediment and solute fluxes from glaciated catchments. The sediment yield from glaciated catchments (those with >30% glacial cover) is often an order of magnitude greater than those of similar, nonglaciated catchments. Remarkably, sediment yield from glacier basins scales with basin area, most likely as a consequence of thicker ice thicknesses and ice fluxes, which increase the rate of subglacial erosion. The rate of glacial erosion usually exceeds the rate of transport of material from the catchment, so that following deglaciation sediment yield remains high for periods of 10
3
–10
5
years. The concentration of ions in glacial runoff is typically less than that of temperate river waters, yet the solute yield from glaciated catchments is similar to that of temperate catchments when scaled by specific runoff. Glaciers are particularly efficient in dissolving carbonates, sulfides, fluid inclusions, and the surfaces of silicate minerals. This is a consequence of the production of fine‐grained, geochemically reactive sediments in subglacial environments and the high water flux through many glaciated catchments. Subglacial chemical weathering is microbially mediated. Hence, glacier beds act as refugia for microbial life, which spans the range from fully oxic to fully anoxic conditions.
Modeling of the Global Water Cycle – Analytical Models
Authors: Liu Yongqiang , Avissar Roni
Published: April 2006

Both numerical and analytical models of coupled atmosphere and its underlying ground components (land, ocean, ice) are useful tools for modeling the global and regional water cycle. Unlike complex three‐dimensional climate models, which need very large computing resources and involve a large number of complicated interactions often difficult to interpret, analytical models are able to provide more direct and intuitive figures of variability and processes in a highly simplified system. They can be a good and efficient alternative modeling tool, especially for studying continental water cycle. This article describes the analytical models developed based on the soil and atmospheric water and energy conservation equations. A fourth‐order model is used to illustrate the perturbation equation, solutions, and physical interpretation. Our understanding of some water cycle variability issues, including timescale, persistence, and major physical parameters and processes, obtained from the analytical models is presented.
Global River Carbon Biogeochemistry
Authors: Richey Jeffrey E
Published: April 2006

The fluxes of dissolved and particulate carbon from land through fluvial systems to the oceans and to the atmosphere represent important pathways in the global carbon cycle. The processes controlling the distributions of solute species in river waters are established initially by weathering within the watershed, and physical transport via runoff. Superimposed on the underlying geochemical and physical processes is production and mineralization by terrestrial and aquatic biota. These factors play out differentially across the world's river basins, producing chemical signatures that vary from river to river. As a global aggregate, there would appear to be a net sink (between continental sedimentation and marine sedimentation and dissolution) of ∼1 to 1.5 Pg year
−1
. These sinks are partially compensated for by the outgassing. These processes are geographically very dispersed, with the continental sedimentation occurring in northern temperate regions, and much of the marine sedimentation and outgassing occurring in more tropical regions.
Markets for Watershed Services
Authors: Tognetti Sylvia S , Aylward Bruce , Mendoza Guillermo F
Published: April 2006

Increasing degradation of watersheds has led to increased recognition of the services they provide in various forms of support for livelihoods and general well‐being, as well as to a greater willingness to pay for them and to cooperate in initiatives to protect them. This is reflected in numerous initiatives, in which market‐based instruments and other supporting institutional arrangements are used as a way to create incentives and to recover the costs of watershed protection, as well as to allocate water more efficiently among various uses. Many of these payment initiatives have focused narrowly on the role of forests in the hydrological regime as a way to justify funding for their conservation, but should be developed in the context of basin‐wide management objectives, which provide a framework for considering the full range of interests that share a common river basin in the context of specific ecosystem functions that support them, and for identifying and quantifying trade‐offs associated with various management options. In addition to forests, this would include consideration of the relative values of all types of land cover and land uses such as wetlands, riparian areas, steep slopes, roads, and management practices. It also requires an accounting for the role of human consumption in the modification of the hydrological cycle, so that these changes can be distinguished from natural variation, and so as to be able to distinguish biophysical from economic causes of scarcity. Economic justification for an initiative may also require that initiatives aimed at protection of freshwater supplies be part of a package of approaches designed to capture the value of multiple ecosystem services found in landscapes, and to resolve conflict among various uses. Given the heterogeneity of landscapes and the site‐specific nature of ecosystem services, a key challenge is to develop the capacity for place‐based approaches to monitoring and assessment. This article provides an overview of the types of economic instruments and institutional arrangements used to capture the value of watershed services, the assumptions on which they are based, institutional challenges faced in implementing them, and the kinds of scientific information needed to identify economic trade‐offs, inform stakeholder negotiations, and support decision‐making.
Acceleration of the Global Hydrologic Cycle
Authors: Roads John , Oglesby Robert , Hoffman Forrest , Robertson Franklin
Published: April 2006

The global hydrologic cycle, which can be conceptually described as evaporation of water vapor from the ocean, transport of water vapor by atmospheric winds to land regions, condensation, and precipitation of atmospheric water back to the surface, and subsequent transport, by streams, of this water back to the ocean, may intensify or accelerate in the future, as the planet warms owing to an increasing greenhouse resulting from increasing emissions of anthropogenic gases. As in many previous studies, increased hydrologic fluxes are found in a 100‐year integration of the NCAR Coupled Climate System Model when forced with increasing CO
2
levels. That is, as the earth warms, the evaporation increases, which not only increases the precipitation rate, but also the subsequent moisture convergence to land regions. However, if this increase in the cycling rate by various processes is measured with respect to the changing atmospheric and surface water reservoirs, then the atmospheric hydrologic cycle may appear to be actually deaccelerating since the atmospheric reservoir in this model is influenced more by the temperature changes than the actual transformation processes are. By contrast the land surface water reservoirs are less affected and thus there does appear to be an accelerated land surface hydrologic cycle, especially at high latitudes, and a coupled land‐atmosphere acceleration, at least over land regions. There are also important regional differences.
Role and Importance of Cryospheric Processes in Climate System
Authors: McConnell Joseph R
Published: April 2006

The cryosphere, which includes seasonal snow, frozen ground, sea ice, glaciers, ice caps, and ice sheets, is one of Earth's five main regimes together with the atmosphere, biosphere, hydrosphere, and pedosphere. It is estimated that the cryosphere contains about 1.8% of all water on Earth but nearly 70% of the freshwater. Interactions between snow and ice cover and the radiation budget make the cryosphere especially important to climate at local to global scales, while strong positive feedback mechanisms mean that the cryosphere is particularly sensitive to climate change. Impurities trapped in glaciers and ice sheets archive detailed, high‐time resolution records of the Earth's changing climate and hydrologic cycle over the past million years. These and other records document repeated variations in the size of the cryosphere including very large, long‐duration changes such as the glacial and interglacial periods as well as much smaller, though still important changes such as the Medieval Warm Period and Little Ice Age during the last two millennia. The cryosphere is shrinking rapidly in response to the current warming, particularly in the Northern Hemisphere.
Data Visualization
Authors: Knopf George K. , Sangole Archana
Published: April 2006

Data visualization exploits statistical, computer graphics, and geometric modeling techniques to transform numeric or symbolic datasets into visual displays that enable analysts to observe patterns in a more intuitive and efficient manner. These diverse techniques reduce both the quantity and the dimensionality of the data to a manageable size, and encode as much information as possible into simple graphical forms and displays. Critical information is represented as differences in color, size, shape, and the relative proximity of graphical icons in the display space. Techniques that generate graphical representations from strings of numeric data are usually referred to as scientific visualization methods. Information visualization, on the other hand, focuses on document databases and information spaces. Scientific data and information visualization techniques are becoming increasingly more important in medicine as clinical staff, practicing physicians, and biomedical engineers need to explore and analyze large complex databases. A deeper understanding of the correlations and interrelationships between constituent data vectors or segments of textual information will lead to improved medical care. Although visualization is a data‐dependent process, the statistical and geometric modeling techniques can be used to synthesize, graphically represent, and analyze these diverse forms of data.
Micromechanical Devices
Authors: Martel Sylvain
Published: April 2006

The miniaturization of mechanical systems, and more specifically micromechanical devices, promise new opportunities in many biomedical applications because of their specific characteristics. These micromechanical devices are much smaller, lighter, faster (e.g., higher resonant frequency), and often more precise or sensitive than their macroscopic counterparts. In particular, micromechanical devices present opportunities in assisting in diagnostic, surgical, and therapeutic applications. Micromechanical devices are also often referred to as micro‐electromechanical systems (MEMS) when combined with electronics, and when conceived for a particular biotechnology‐based application, they are often referred to as bioMEMS (bio‐micro‐electromechanical systems). Today, micromechanical devices exist in many environments such as automotive, consumer, industrial, aerospace, and biomedical. Biomedical applications for micromechanical devices are an area that is forecast to experience substantial growth. An example is the implantable and disposable blood pressure sensor, one of the earliest bioMEMS applications, which continues to grow. MEMS‐based lab‐on‐a‐chip for point‐of‐care diagnostics on a patient is another promising application in biomedical where the time and cost associated with conventional methods can be reduced significantly. Of particular interest in the biomedical field are micromechanical devices such as microtransducers in the form of micromechanical sensors and micromechanical actuators including micromotors.
Nerve Stimulation
Authors: Grill Warren M.
Published: April 2006

This chapter describes electrical activation of the nervous system with an emphasis on stimulation of peripheral nerve fibers. Electrical stimulation of the nervous system is a widespread method to study the form and function of the nervous system and a technique to restore function following disease or injury. The objective of this chapter is to present the fundamental principles underlying nerve fiber excitation, and the focus is on electrical stimulation of peripheral myelinated nerve fibers. The fundamental understanding provided by quantitative analysis is required for rational design and interpretation of therapies employing electrical stimulation.
Obstructive Sleep Apnea: Electrical Stimulation Treatment
Authors: Sahin Mesut , Huang Jingtao
Published: April 2006

Obstructive sleep apnea (OSA) is an intermittent occlusion of the upper airways resulting in frequent arousals during sleep. It is a prevalent problem among middle‐aged overweight males. Neuromuscular and anatomical factors play a major role predisposing the upper‐airways for obstructions. The limited success of current therapies and the strong correlation of the obstructions with the upper‐airway muscle mechanics has inspired researchers to apply the experience gained in the field of functional electrical stimulation to this common sleep disorder. A number of upper airway muscles have been tested in animal models and human subjects for their potential to remove or prevent the obstructions. Electrical activation of the extrinsic muscles of the tongue through the stimulation of the XIIth cranial (hypoglossal) nerve stands out as the most promising approach today. In this article, we review these recent attempts to treat OSA by electrical activation of the upper‐airway muscles.
Sleep
Authors: Achermann Peter
Published: April 2006

Sleep is a reversible, periodical state of quiescence that is more than the absence of being awake—it is an active state that is regulated. Typical changes in the pattern of the electroencephalogram (EEG) serve to discriminate sleep and waking. Modern sleep research is intimately linked to the ability of recording the EEG and to its quantitative analysis. The cyclic alternation of the two basic sleep states, non rapid‐eye‐movement (non REM) sleep and rapid‐eye‐movement (REM) sleep, is one of the hallmarks of sleep. Sleep homeostasis denotes a basic principle of sleep regulation. A sleep deficit elicits a compensatory increase in the intensity and duration of sleep, whereas excessive sleep reduces sleep propensity. EEG slow‐wave activity (SWA), a correlate of sleep intensity, serves as an indicator of sleep homeostasis in nonREM sleep. The level of SWA is determined by the duration of prior sleep and waking. Recent evidence exists for a local use‐dependent facet of sleep regulation. Selective unihemispheric regional cerebral activation during waking gives rise to a predominant increase of sleep intensity in the previously activated region as reflected by enhancement of SWA.
Spinal Cord Stimulation System
Authors: Guo Songfeng , Brown Karl , Grindle Garrett , Zipfel Emily
Published: April 2006

Spinal cord stimulation (SCS) is an advanced therapy and method of pain management for certain types of chronic pain. SCS has thus far been shown to be more effective for neuropathic forms of pain than for nociceptive forms of pain. The history of electrical stimulation for pain relief is reviewed as well as the basic anatomy of the spinal cord. Although its exact mechanisms are still unknown, SCS involves both neurophysiological mechanisms and pharmacological mechanisms to achieve paresthesia. The implantable pulse generator (IPG) and external radio frequency (RF) spinal cord stimulators, their parameters, and implantation procedures are described. Future success of SCS will depend on improving the model for SCS's mechanisms, improving the patient selection criteria, and optimizing the lead configuration for improved pain relief.
Skin Lesions: Burns
Authors: Roa Laura M. , Reina-Tosina Javier , Gómez-Cía Tomás
Published: April 2006

Burn injuries are one of the most aggressive lesions that the human body can suffer with certain probabilities of survival. Recent advances on the treatment of critical burn patients have run in parallel with beneficial contributions from different fields of biomedical engineering, ranging from modeling and simulation techniques to tissue engineering to information technologies and communications applied to this life‐threatening trauma. The use of mathematical models has led to a better understanding of the physiopathology of the burn patient, and relying on their capabilities for knowledge generation and integration, it has been possible to propose therapies with the quantification of the loss of fluids, electrolytes, and colloids as a function of burn extent and depth and the time interval since the injury. The reconstruction of skin is another challenge for plastic surgeons that has improved by applying tissue engineering concepts. Especially in recent years, the improvement of information technologies and communications has played a fundamental role in improving the quality of the treatment to burn patients, with telemedicine as a clear example.
Preparation of Y‐TZP Nanoceramics by Gelcasting‐Pressing Method and Pressureless Sintering
Authors: Zhang Y. S. , Hu L. T. , Chen J. M. , Liu W. M.
Published: April 2006

ZrO2(3Y) nano‐sized powders have been synthesized by chemical coprecipitation technique. The gelcasting‐pressing (gel‐casting and dry pressing) method and pressureless sintering were applied to fabricate Y‐TZP nanoceramics. A fully dense pellet of ZrO2(3Y) is obtained after sintering at 1250 °C for 2h, the reason for the good sintering behavior is believed to be both the increase in relative density and the decrease in pore size.
Preparation and Tribological Properties of Inorganic Fullerene‐like MoS2
Authors: Zou T. Z. , Tu J. P. , Huang H. D. , Lai D. M. , Zhang L. L. , He D. N.
Published: April 2006

The decomposition temperature had little effect on the particle size with the addition of surface agent. It was just the crystallization that different from each other. With increasing the temperature, the peak width of XRD patterns sharpened, indicating that the crystallization of MoS2 particles went better.
Investigations on Damage in a Filled Epoxy Resin
Authors: Depoorter N. , Coutellier D. , Mužic M. , Berg‐Pollack A. , Cai Y. , Zimmermann A.
Published: April 2006

The demand for high‐end products is rising. Thus, the ability to predict the deterioration of materials under service conditions becomes a critical task. This work studies the damage evolution in a filled epoxy resin submitted to low cycle fatigue loading. A TEM analysis shows delamination at the interface between matrix and particles, providing evidence of damage. The cyclic fatigue is modeled by a continuum damage mechanics approach.
Improved Hydrogen Storage in the Metal‐Organic Framework Cu3(BTC)2
Authors: Krawiec P. , Kramer M. , Sabo M. , Kunschke R. , Fröde H. , Kaskel S.
Published: April 2006

A new pressure‐free synthesis method was developed producing the porous material Cu3(BTC)2 (BTC = benzene tricarboxylate) with a very high micropore volume up to 0.62 cm3g–1. The compound is a promising nanoporous solid for adsorptive hydrogen storage under cryogenic conditions with a capacity of 2.18 wt% which is higher than that of IRMOFs and other coordination polymers.
Deposition of Aluminium Alloy Al12Si by Cold Spraying
Authors: Zhao L. , Bobzin K. , He Dingyong , Zwick J. , Ernst F. , Lugscheider E.
Published: April 2006

Al12Si was deposited by cold spray process. The influence of spray parameters on coating build up and coating microstructure was investigated. The process gas temperature was the crucial parameter for deposition of Al12Si. Increasing process gas temperature led on the one hand to a strong increase in the coating thickness, on the other hand to increasing coating porosity. In addition, the spray distance and the process gas flow rate could also have a significant influence, especially when spraying with higher process gas temperatures.
Influence of Different BN Grades on Sintering Behaviour, Microstructure and Properties of Machinable Si3N4‐MoSi2‐BN Composites
Authors: Medri V. , Dalle Fabbriche D. , Melandri C. , Guicciardi S. , Bellosi A.
Published: April 2006

The machinability of ceramic materials can be improved by the addition of hexagonal‐BN: the expensive diamond‐based tools could be replaced by cemented carbides tools lowering the machining costs. Anisotropic materials are obtained by hot pressing due to h‐BN plate‐like structure. Si3N4‐BN composites are suitable as rotor seals for gas turbine engines in the ranges 1000°C–1300°C. Oxidation resistance can be improved up to 1500°C by the addition of MoSi2.
Optimization of Mechanical Properties of NiAl‐base Alloy by Suction Casting
Authors: Huai K. W. , Guo J. T. , Li H. T. , Yang R.
Published: April 2006

The suction‐cast NiAl‐Cr(Mo)/Hf alloy exhibits a refined microstructure and extended solid solubility. Significant improvement in room temperature ductility and strength was achieved by adopting suction casting technique. In addition, their elevated temperature strength also got slightly increase. The optimized mechanical properties can be attributed to the fine interlamellar spacing, the extended solid solubility and the increased cell eutectic zone as well as the refined Heusler phase.
Controlling Microstructure in Magnesium Alloys: A Combined Thermodynamic, Experimental and Simulation Approach
Authors: Böttger B. , Eiken J. , Ohno M. , Klaus G. , Fehlbier M. , Schmid‐Fetzer R. , Steinbach I. , Bührig‐Polaczek A.
Published: April 2006

How can the microstructure of lightweight magnesium castings be controlled in industrial processes? By tuning the alloy to the process. To speed up the search for optimal alloy compositions related to the type of casting process we employ the CalPhad technique for predicting the stability of primary and secondary phases and the Phase Field technique to predict kinetics of transformation and morphology of the microstructure. The predictions are compared to critical casting experiments. The figure shows the calculated microstructure in the outer zone of a chill casting of AZ31 magnesium alloy.
Progress in the Characterisation of Structural Oxide/Oxide Ceramic Matrix Composites Fabricated by Electrophoretic Deposition (EPD)
Authors: Stoll E. , Mahr P. , Krüger H.‐G. , Kern H. , Dlouhy I. , Boccaccini A. R.
Published: April 2006

Electrophoretic deposition (EPD) is a very convenient technique for the processing of fibre reinforced ceramic matrix composites. A significant progress in the application of EPD to manufacturing large composite components based on alumina matrices and Nextel® woven fibre mat as reinforcement is presented. The EPD process enables high infiltration of alumina nanoparticles onto 2‐D fibre mats, thus leading to composites of high density and microstructural homogeneity. The mechanical properties of the composites at room and high temperatures are charactersised.
Improvement of Mechanical Properties of Powder Metallurgical NiTi Shape Memory Alloys
Authors: Mentz J. , Bram M. , Buchkremer H. P. , Stöver D.
Published: April 2006

An improvement of the mechanical properties of powder metallurgically produced NiTi shape memory alloys was attained by reducing the impurity contents of oxygen and carbon. Elongation at fracture was increased to 16.5 % for Hot Isostatically Pressed (HIP), as well as for net‐shape samples produced by Metal Injection Moulding (MIM) with plastic deformation before fracture. Furthermore, an enlargement of the utilisable strain of the shape memory effect itself was detected.
Coupling Mechanical Competence and Bioresorbability in Bioglass®‐Derived Tissue Engineering Scaffolds
Authors: Chen Q. , Boccaccini A. R.
Published: April 2006

The transformation of a mechanically competent crystalline phase into a biodegradable amorphous phase in 45S5 Bioglass®‐derived foam scaffolds immersed in simulated body fluid has been investigated. This transformation enables mechanical competence (e.g. compression strength) to be coupled with biodegradability in one optimised scaffold. The present work shows that the goal of an ideal scaffold for bone tissue engineering that provides mechanical support temporarily and biodegrades at later stages at a controlled rate is achievable using Bioglass®‐based foams.
Process Shrinkage and Accuracy during Indirect Laser Sintering of Aluminium
Authors: Sercombe T. B. , Hopkinson N.
Published: April 2006

In this paper we have investigated the shrinkage and accuracy of indirect selective laser sintered aluminium. The majority of the ∼1.2‐1.4% linear shrinkage occurs during the infiltration of the skeleton structure. By optimising scale and offset parameters during selective laser sintering of the preforms, accuracy similar to that of casting processes can be achieved.
Atmospheric Plasma Spraying of Thermal Barrier Coating Material ZrO2‐7%Y2O3 using On‐line Particle Monitoring
Authors: Zhao L. , Bobzin K. , Ernst F. , Lugscheider E.
Published: April 2006

The properties of in‐flight ZrO2‐7%Y2O3 particles were investigated using a particle diagnostic system DPV‐2000 during atmospheric plasma spraying. The deposition efficiency of spray powder was correlated to spray parameters and particle properties. Particle velocity increased significantly with increasing electric current intensity and argon flow rate. Particle temperature increased significantly with decreasing argon flow rate and increasing electric current intensity. The argon flow rate was the only crucial parameter for the deposition efficiency under the given spray conditions.
Cover Picture: Controlling Microstructure in Magnesium Alloys: A Combined Thermodynamic, Experimental and Simulation Approach (Adv. Eng. Mater. 4/2006)
Authors: Böttger B. , Eiken J. , Ohno M. , Klaus G. , Fehlbier M. , Schmid‐Fetzer R. , Steinbach I. , Bührig‐Polaczek A.
Published: April 2006

The cover picture shows four different microstructures of magnesium alloys resulting from different grain refinement mechanisms. More about a combined thermodynamic, experimental and simulation approach for controlling microstructure in magnesium alloys can be found in the paper by Böttger et al. on page 241 in this issue.
Catalytic kinetics of quaternary ammonium poly(styrene‐co‐methylstyrene) resin
Authors: Wu Ho‐Shing , Lin Hung‐Ju
Published: April 2006

The catalytic kinetics and synthesis of poly(styrene‐co‐chloromethylstyrene) resin of different degrees of crosslinkages and ring substitutions were investigated by copolymerizing styrene and chloromethylstyrene through crosslinking with divinylbenzene. Poly(styrene‐co‐chloromethylstyrene) quaternary ammonium salt was obtained with activating poly(styrene‐co‐chloromethylstyrene) resin with tertiary amine. More than 20 types of poly(styrene‐co‐chloromethylstyrene) quaternary ammonium catalyst were prepared, with reaction conditions including immobilized time (0.125∼4 days), concentration of tertiary amine (0.1∼2 kmol/m3), kinds of solvents in immobilization (methanol, ethyl alcohol, and DMF), and kinds of tertiary amines (trimethylamine, triethylamine, tripropylamine, tri‐n‐butylamine, tri‐n‐pentylamine, tri‐n‐hexylamine, and tri‐n‐octylamine). These catalysts were used to achieve the optimum allylation of phenol. The reactions were conducted and studied individually with either equal mole or equal weight of catalyst. The best reactivity for the allylation of phenol was obtained when the structure of the quaternary ammonium catalyst was 10% degree of ring substitution and 2% degree of crosslinkage activating with trihexylamine. The turnover number and the effectiveness factor were also calculated. © 2006 American Institute of Chemical Engineers AIChE J, 2006
How many work‐related injuries requiring hospitalization in British Columbia are claimed for workers' compensation?
Authors: Alamgir Hasanat , Koehoorn Mieke , Ostry Aleck , Tompa Emile , Demers Paul A.
Published: April 2006

Background

Workplace compensation claims datasets represent an important source of information on work‐related injuries. This study investigated the concordance between hospital discharge records and workers' compensation records for work‐related serious injuries among a cohort of sawmill workers in British Columbia (BC), Canada. It also examined the extent to which workers' compensation capturing patterns varied by cause, severity of injuries, and demographic characteristics of workers.

Methods

Work‐related injuries were identified in hospitalization records between April 1989 and December 1998, and were matched by dates and description of injury to compensation records.

Results

The agreement between the hospital records and compensation records was good (κ = 0.84, P < 0.01). A lower claim reporting rate for work‐related hospitalization was observed for older and non‐white workers. More serious injuries defined by longer length of stay and emergency admissions were more likely to be reported. Falls, struck against, and overexertion injuries had lower reporting rates; whereas, machinery‐related, cutting/piercing, and caught in/between injuries had higher reporting rates.

Conclusions

When compared with hospital discharge records, the compensation agency underreported incidents of serious work‐related injuries by 10–15% among the sawmill workers. Am. J. Ind. Med. 2006. © 2006 Wiley‐Liss, Inc.
A cohort mortality study of leather tanners in Tuscany, Italy
Authors: Iaia Tonina E. , Bartoli Dusca , Calzoni Paola , Comba Pietro , De Santis Marco , Dini Flavia , Farina Giuseppe A. , Valiani Mauro , Pirastu Roberta
Published: April 2006

Background

Work in leather tanning may involve exposure to a wide range of chemicals. Some of these are carcinogens or suspected carcinogens. Increased risk for a number of cancers have been reported, although there are considerable inconsistencies between studies. The present study investigates the mortality of leather tanners in Tuscany, Italy.

Methods

Tanneries were selected from the 1996 Valdarno Inferiore Tanneries Census and were in operation since December 31, 1970. Employees were followed until December 31, 1998 through company records, and the National and Regional Death Index. Demographic and work history data were abstracted from company payrolls. Regional mortality rates were used to calculate Standardized Mortality Ratio (SMR). Analyses were completed for the overall cohort (men and women) and for men who ever worked as of finisher, chrome tanners, and vegetable tanner (only men).

Results

The cohort consisted of 4,874 workers (4,150 males and 724 females) employed in 92 tanneries active in 1996 and operating on December 31, 1970. Ascertainment of vital status and cause of death were completed for all individuals by the end of follow‐up, December 31, 1998. Males showed increases for cancer of the endocrine glands (SMR 5.67, 4 observed (obs), 90% Confidence Intervals (CI) 195–1,308), blood diseases (SMR 3.29, 4 obs, 90% CI 112–753), mental disorders (SMR 1.95, 6 obs, 90% CI 85–385), violence and accidents (SMR 1.30, 54 obs, 90% CI 102–163). Mortality from myeloid leukemia was increased in males (SMR 2.08, 5 obs, 90% CI 82–437) and in females (SMR 5.99, 2 obs, 90% CI 106–1,887). One death from nasal cancer was observed versus 0.2 expected. Mortality from lung cancer was increased among finishers (SMR 1.45, 19 obs, 90% CI 95–212), an increase was observed also for bladder cancer (SMR 1.25, 2 obs, 90% CI 22–393) and pancreatic cancer (SMR 1.20, 2 obs, 90% CI 21–379).

Conclusions

The study confirms previous observations among tanners of increased mortality from lung, bladder, and pancreatic cancer. Noteworthy are the increased mortality from myeloid leukemia together with the new findings of an increased mortality from endocrine glands tumors, blood diseases, and psychiatric disorders which should be considered with caution because of the small number of cases and the novelty of the observation. Am. J. Ind. Med. 2006. © 2006 Wiley‐Liss, Inc.
Occupational endotoxin‐exposure and possible health effects on humans (review)
Authors: Liebers Verena , Brüning Thomas , Raulf‐Heimsoth Monika
Published: April 2006

Background

Endotoxins are commonly found at workplaces where large amounts of bioaerosols are generated. In Germany, especially since the Ordinance on Safety and Health Protection related to work involving biological agents (Biostoff‐Verordnung) became effective (1999), threshold limit values are widely discussed. Up to the present, endotoxin values are measured with non‐uniform methods and therefore values are of limited benefit for classification of exposure groups. In Germany there is no threshold limit value for endotoxin.

Methods

Relevant literature of the last 20 years was selected from Medline and discussed.

Results

In this review we focused on the impact of endotoxin exposure on human health with special respect to the measurements on workplace and methodological aspects of endotoxin determination. Methods for sampling and endotoxin determination have to be validated, optimized, and standardized first.

Conclusion

The adverse health effects of endotoxins are known, standardization of measurements is a necessary goal and protection measures should be established immediately. Am. J. Ind. Med. 2006. © 2006 Wiley‐Liss, Inc.
International study on low‐grade primary central nervous system lymphoma
Authors: Jahnke Kristoph , Korfel Agnieszka , O'Neill Brian Patrick , Blay Jean‐Yves , Abrey Lauren E. , Martus Peter , Poortmans Philip M. P. , Shenkier Tamara N. , Batchelor Tracy T. , Neuwelt Edward A. , Raizer Jeffrey J. , Schiff David , Pels Hendrik , Herrlinger Ulrich , Stein Harald , Thiel Eckhard
Published: April 2006

Objective

The aim of this study was to characterize the clinical presentation, course, and outcome of low‐grade primary central nervous system lymphoma.

Methods

Cases were assessed in a retrospective series collected from 18 cancer centers in 5 countries.

Results

Forty patients (18 men, 22 women; median age, 60 years [range, 19–78]) were identified. Involvement of a cerebral hemisphere or deeper brain structures was seen in 37 patients, only leptomeningeal involvement in 2 patients, and spinal cord disease in 1 patient. Chemotherapy/radiotherapy was conducted in 15 patients, radiotherapy alone in 12, chemotherapy alone in 10, and tumor resection alone in 2, whereas 1 patient received no treatment. The median progression‐free, disease‐specific, and overall survival were 61.5 (range, 0–204), 130 (range, 1–204), and 79 (range, 1–204) months, respectively. Only age 60 years or older was associated with shorter progression‐free (p = 0.009), disease‐specific (p = 0.015), and overall survival (p = 0.001) in multivariate analysis.

Interpretation

Low‐grade primary central nervous system lymphoma differs from the high‐grade subtype in its pathological, clinical, and radiological features. It has a better long‐term outcome than primary central nervous system lymphoma in general with age 60 years or older adversely affecting survival. Ann Neurol 2006
Synthesis of Some Novel Azo Derivatives of 3,5‐Dimethly‐1‐(2‐hydroxyethyl)pyrazole as Potent Analgesic Agents
Authors: Oruç E. E. , Koçyigit‐Kaymakçioglu B. , Oral B. , Altunbas‐Toklu H. Z. , Kabasakal L. , Rollas S.
Published: April 2006

A series of 1‐(2‐hydroxyethyl)‐3,5‐dimethylpyrazolylazo derivatives, incorporating thiosemicarbazide 2a–c, 1,3,4‐thiadiazole 3a–c, and 1,2,4‐triazole‐3‐thione 4a–c were synthesized. The structure of these novel synthesized compounds 2a–c, 3a‐c, and 4a–c was confirmed by spectral analysis. All these compounds were screened for their analgesic activity. Hot‐plate and tail‐immersion tests were used for the determination of the analgesic activity. Morphine, an analgesic through both spinal and supraspinal pathways, was used as a standard test drug. All compounds were administered at a dose of 100 mg/kg i.p. Among the compounds, 2‐(butylamino)‐5‐[((1‐(2‐hydroxyethyl)‐3,5‐dimethylpyrazole‐4‐yl)azo)phenyl]‐1,3,4‐thiadiazole 3a and 4‐[((1‐(2‐hydroxyethyl)‐3,5‐dimethylpyrazole‐4‐yl)azo)phenyl]‐4‐(2‐phenethyl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione 4c showed analgesic effects in both tests. Especially 4c exerted strong analgesia starting at 30 min after injection.