bluuebunny/crossref_metadata_2025 huggingface dataset:
Intelligent Polymer Systems
Authors: Wallace G. G. , Innis P. C. , Moulton S. E.
Published: July 2004

Inherently conducting polymers (ICPs) are a unique class of materials that have the capability to not only conduct electricity but also undergo redox changes in response to an environmental stimulus. No other class of material is capable of undergoing such a broad range of transductions and as a result ICPs have been investigated for applications in an amazing array of areas. This review highlights the application of the ICP in areas such as sensing technologies, polymer actuators, molecular electronics, electrochromics, and energy conversion and storage. The facile nature of the ICP, in combination with novel polymer processing strategies, lends itself to the development of unique solutions in a diverse array of areas. The incorporation of the ICP into these technologies will ultimately lead to development of intelligent polymer systems, partly because of the amazing redox capabilities of these polymers.
Ethylene Oxide Polymers
Authors: Back Darlene M. , Schmitt Robert L.
Published: July 2004

Ethylene oxide polymers are high molecular weight (>100,000) water‐soluble thermoplastic polymers. This article reviews the effect of shear, pH, salt, and temperature on the physical and chemical properties of poly(ethylene oxide) solutions and melts. Industrial uses of the unique properties of poly(ethylene oxide) in fields such as flocculation, pharmaceutical excipients, adhesives, coatings, and personal care are summarized.
Polymer Brushes
Authors: Advincula Rigoberto C.
Published: July 2004

Polymer materials in confined dimensions are of great interest theoretically and experimentally. The investigation of polymer brushes involves the use of surface‐sensitive analytical tools and theoretical models using self‐consistent field theory as well as Monte Carlo simulations. However, of much more recent interest is the investigation of different polymerization mechanisms that can be employed in the so‐called surface initiated polymerization (SIP) or “grafting from” methods where initiators are tethered to surfaces.

Polymer brushes

are

polymer materials prepared and assembled from end‐tethered or SIP systems where the average distance between grafting points can be much smaller than the radius of gyration (
R
g
)

. Macromolecule systems involving polymer blends, block copolymers, complex polymer architectures, and other functional polymers can have intereting properties when confined to surfaces and interfaces. Analogies in bulk or solution do not necessarily hold when applied to the unique anisotropy and dimension of a flat surface or a colloidal particle. It is expected that interesting applications will be derived from the direct tethering of macromolecules in areas such as lubricants, flocculation, membranes, bioapplications, microarrays, lithography, and others.
Ellipsometry
Authors: Collins Robert W.
Published: July 2004

Ellipsometry is an optical measurement technique that involves generating a monochromatic or quasimonochromatic light beam in a known polarization state and reflecting it from a sample having a planar, specularly reflecting surface. By measuring the polarization state of the reflected beam, the ellipsometric angles (ψ, Δ) can be determined, and upon detailed analysis, these angles yield information about the sample. Such information includes the optical properties, that is, the index of refraction and extinction coefficient, for a bulk sample or the thickness and optical properties for one or more thin films on the sample surface having plane‐parallel interfaces. For an isotropic sample, the angles (ψ, Δ) are defined by tanψexp(iΔ) = rp/rs, whererpandrsare the complex amplitude reflection coefficients for linear p and s polarization states, for which the electric field vibrates parallel and perpendicular to the plane of incidence, respectively. Several variations of the ellipsometry experiment have been developed. In spectroscopic ellipsometry (SE), (ψ, Δ) are measured continuously versus the wavelength of the light beam, and in real‐time ellipsometry (RT‐E), (ψ, Δ) are measured continuously versus time at fixed wavelength. The latter two modes can be combined to yield real‐time SE (RT‐SE), utilizing an instrument with a linear photodiode array for parallel detection at many wavelengths simultaneously. In imaging ellipsometry (IE), (ψ, Δ) are measured over a two‐dimensional (2‐D) area of a nonuniform sample surface using an instrument with a 2‐D charge‐coupled device (CCD) as the detection system. The most widely used instruments for SE and RT‐SE span the spectral range from the ultraviolet (200–300 nm) to the near infrared (800 nm). Over this spectral range, the optical properties deduced from SE provide information on the processes of absorption and dispersion originating from the valence electrons in semiconductors and dielectrics and from the conduction electrons in metals. Specialized SE equipment designed for the infrared range can be more effective for chemical identification of thin films, based on the absorption processes originating from the vibrational modes of chemical bonds.
Laser Physics
Authors: Zayhowski John J. , Kelley Paul L.
Published: July 2004

This article concerns the physics of lasers, including population inversion, pumping processes, stimulated emission, and resonators. Important laser characteristics such as narrow spectral linewidth, high spatial collimation, and ultrashort pulses are discussed. A review is given of several types of laser media, laser dynamics, and modes of laser operation. Methods for control of laser output and practical considerations in laser design are considered. Finally, there is a discussion of nonlinear optical techniques for frequency conversion of laser radiation.
Lasers, Free‐electron
Authors: Pellegrini Claudio , Reiche Sven
Published: July 2004

Free‐electron lasers are radiation sources, based on the coherent emission of synchrotron radiation of relativistic electrons within an undulator or wiggler. The resonant radiation wavelength depends on the electron beam energy and can be tuned over the entire spectrum from micrometer to X‐ray radiation. The emission level of free‐electron lasers is several orders of magnitude larger than the emission level of spontaneous synchrotron radiation, because the interaction between the electron beam and the radiation field modulates the beam current with the periodicity of the resonant radiation wavelength. The high brightness and the spectral range of this kind of radiation source allows studying physical and chemical processes on a femtosecond scale with angstrom resolution.
Lasers, Semiconductor
Authors: Ogasawara Nagaatsu , Ito Ryoichi
Published: July 2004

Following a brief history of semiconductor lasers, this article describes their operation principles in relation to their device structures and materials. Their fundamental operation characteristics, including the static, spectral, and dynamic aspects, are then presented. Finally, the current state of the art in semiconductor laser technology is described by reviewing up‐to‐date devices incorporating new structures and new functions.
Lasers, Solid‐state
Authors: Fan Tso Yee
Published: July 2004

An overview of solid‐state lasers, which are lasers using doped, dielectric solids as the gain media, is presented. The article includes information on the history, materials physics, technology, and application of these devices.
Magneto‐optical Devices
Authors: Castera Jean Paul , Suzuki Takao
Published: July 2004

The history of magneto‐optical effects is first introduced. Then the types of magneto‐optical effects are described, which include the varieties of the interactions of electromagnetic waves with magnetization or spins in solids. The physical origin of the magneto‐optical effects is phenomenologically discussed. Both magnetic circular/linear birefringence and dichroism, and Void and Cotton–Mouton effects are discussed. Then, some representatives of magneto‐optical materials of transmission (Faraday effect) and reflection (Kerr) types are described. Finally, the applications of magneto‐optical effects are presented, which include the isolators, circulators, modulators, deflectors, magneto‐optical imaging, field sensors, magneto‐optical sensors, and magneto‐optical recording and microwave waveguides. In particular, a recent development of magneto‐optical recording is summarized, which highlights the various novel methods of increasing recording density.
Modulators and Demodulators, Optical
Authors: LiKamWa Patrick , Yao Shi‐Kay , Young Eddie H.
Published: July 2004

Modulation is a means of adding a signal information to an energy carrier used for transmission. Demodulation is the process of extracting the signal information from the carrier. Electromagnetic waves have been used extensively as the carrier for radio and television broadcasting as well as wireless and satellite telephony and data communications. Optical waves are electromagnetic waves that are at the much higher end of the frequency spectrum compared to radio frequencies. Therefore, information can be sent at much higher rates using optical carrier waves than using radio waves. In this chapter, the application and the technology of various optical modulators are described. The various forms of modulation formats and demodulation techniques are also discussed.
Optical Communications
Authors: Kogelnik Herwig
Published: July 2004

This article discusses the fundamentals of optical fiber transmission technology and its basic building blocks. It aims to explain the principal characteristics of optical fibers, such as chromatic dispersion, of optical‐fiber amplifiers, including the noise they generate, and of semiconductor lasers. Also included is a discussion of optical receivers and their sensitivities, of nonlinear phenomena in optical‐fibers, of solitons, and of various transmission network architectures such as passive optical networks (PONs).
Optical Computing
Authors: Tanida Jun , Ichioka Yoshiki
Published: July 2004

Optical computing is an area of technology for information processing that utilizes excellent features of light. Beginning with some historical background of this technological field, the concept of optical computing is described with respect to definition, motivation, advantages, targets, and classifications. Then two major categories, analog optical computing and digital optical computing, are used to explain concrete instances of this technology. Analog optical computing includes Fourier image processing, acoustooptical signal processing, optical neural computing, and spatiotemporal information processing. Digital optical computing covers logic gates and circuit constructions, computing paradigms, optical computer architectures, and VLSI photonics. Finally, some comments on potential applications of optical computing are added to suggest effective areas for this technological field.
Interconnections, Optical
Authors: Matsumoto Takao , Trewhella Jean
Published: July 2004

Although progress has been made in optical interconnections, electrical interconnections continue to dominate most of the hierarchical interconnect layers that comprise computer systems. (The delay in the industry's move to optics is largely due to the continued improvements in electrical links, most notably the addition of equalization schemes [1].) The challenges faced by electrical interconnections [2] are described along with a presentation of the potential benefits optical interconnections afford. Commercial success for optical interconnections has largely been in rack‐to‐rack links, where the distances are great enough to require the low loss advantages of optical transmission. Further work on optical schemes for each layer of interconnection hierarchy, rack to rack, board to board, and intraboard is presented. These schemes can be broken into two general types of guided wave solutions that use fibers or waveguides as transmission media and free‐space solutions, which require only the optical elements. Advantages and examples of links using each type are described. It is shown that free‐space optical interconnections board to board can reduce wiring congestion dramatically over electrical or guided wave approaches, which force all interconnections to pass between the boards through the backplane. The density achievable can be further improved by employing 3D interconnection arrangements which are discussed in the intraboard examples. Optical interconnection will gradually penetrate from the outer levels of the systems to the inner as the technology matures, but all of these interesting possibilities will remain possibilities unless future areas of study include focus on low cost, small size for high density and high reliability of optical interconnections and devices.
Data Storage, Optical
Authors: Milster Tom D.
Published: July 2004

In its most general definition, optical data storage is simply using light as a tool to store and retrieve data. Optical data storage is found in popular consumer products. Compact Discs (CDs), Digital Versatile Discs (DVDs), and MiniDiscs (MDs), are all forms of optical data storage. More advanced forms of optical data storage include high‐speed devices and library products. All optical data storage devices use optical principles to achieve high data density, rugged packaging, reliable information retrieval, and cost‐effective production. There are many forms of optical storage media and many types of optical systems used to scan data. This chapter discusses the basic principles of optical data storage, types of commercial optical media available in 2003, several performance parameters, and some interesting prospects for future systems.
Optical Tomography
Authors: Hillman Elizabeth M. C.
Published: July 2004

Optical tomography (OT) is an imaging technique that uses near‐infrared (NIR) and visible light to resolve the internal structure of scattering objects. OT has recently been the focus of much development as a method for imaging living tissue such as the breast and brain. By using NIR light, it is possible to investigate the hemoglobin in bloodin vivo, since hemoglobin is a strong NIR absorber compared to other tissue constituents. Using spectroscopic techniques to extract the oxygenation state of the hemoglobin in tissue can provide information about the functional state of the tissue, allowing detection of tumors, hemorrhages, and other abnormalities. This article introduces the basic concepts of medical OT, giving two detailed examples of instrumental approaches. The physics of light propagation in scattering tissue and the various techniques for tomographic image reconstruction are then detailed, followed by a review of some of the latest novel approaches to OT.
Nonlinear Optics
Authors: Flytzanis Christos
Published: July 2004

We present an unified overview and classification of the main nonlinear optical effects and the underlying nonlinear optical interactions. The physical origin of these effects is analyzed and related to material features and their behavior, their characteristics and efficiency are discussed in terms of the nonlinear propagation equations. Some aspects related to nonlinear optical materials and devices are presented and connections with quantum optics, nonlinear spectroscopy and optoelectronics are stressed.
Physiological Optics
Authors: Jüttner Martin
Published: July 2004

Physiological optics is concerned with the perceptual processes in the eye and its associated neuronal structures in the brain. This article provides an overview of the structure and functionality of the visual system, and of experimental and analytical techniques used to study the principles of visual information processing. First, the anatomy of the eye and the various stages of the optical pathway from the retina to the visual cortex are considered in some detail. The concept of receptive fields is introduced and related to the theoretical framework of spatial‐frequency channels. A range of tools and techniques used in neurophysiological and psychophysical vision research are reviewed and compared. This provides the basis for a detailed discussion of elementary visual sensations, including the perception of brightness, depth, movement, and shape, both with regard to their phenomenology and their neurophysiological foundations. Finally, the role of such elementary sensations for higher‐level visual processes is considered by relating them to current theories of object recognition.
Underwater Optics
Authors: Dolin Lev S. , Levin Iosif M.
Published: July 2004

Four major subjects of the underwater optics are especially important, both for fundamental study of interaction between light and water and for various technical applications. These are (1) inherent optical properties (IOP) of natural waters; (2) propagation of natural and artificial light in the water; (3) optical methods for investigation of natural waters, and (4) underwater imaging. These four items form the main content of the paper and determine the titles of its four main sections.

Section 2 presents the definitions of IOP determining light absorption and scattering in water. Methods of measuring IOP are discussed, and data on spatial and spectral distributions of IOP in natural waters are given. Physical and empirical low‐parametric models considered in the section make it possible to determine the whole set of IOP distributions, based on few measurements. Section 3 deals with the underwater light fields. Methods for solving the radiative transfer equation are considered. The section presents data on the solar irradiance and angular radiance distributions near the sea surface and at the sea depth, as well as on the light field of artificial sources. Optical methods for investigation of natural waters are discussed in Sect. 4. This section is mainly concerned with the problem of remote sensing of phytoplankton, suspended and dissolved matters by measuring the ocean color, with the account of algorithms for atmospheric correction of satellite measurements. Finally, Sect. 5 is devoted to the problem of underwater imaging. The presented theory connects the image parameters, such as modulation transfer function, contrast, signal/noise ratio with the parameters of light sources, detectors, water, and target. Comparison of the sighting range and spatial resolution in water ensured by different underwater imaging systems is given.
Photoemission and Photoelectron Spectra
Authors: Himpsel Franz J. , Lindau Ingolf
Published: July 2004

Applications of photoelectron spectroscopy and related techniques are reviewed. They include photoelectric yield spectroscopy, absorption spectroscopy from core levels, photoelectron spectroscopy of core‐level shifts (XPS or ESCA), angle‐resolved photoemission and inverse photoemission, EXAFS, and photoelectron diffraction. These techniques provide information about structure, bonding, and electronic states of atoms, molecules, solids, surfaces, and nanostructures. Advances in detectors and light sources, such as high‐resolution multidetection and synchrotron radiation from undulators, are breaking ground for new applications. Among those are element‐resolved microscopy and high‐resolution spectroscopy of the electronic states relevant to magnetism, superconductivity, and transport properties.
Polarization Optics, Polarimeters and Polarization Spectrometers
Authors: Hermann Gerd
Published: July 2004

Polarimeters, employing polarization optics, are well known as highly precise and accurate instruments for determining optically active substances. Even simple manual polarimeters offer high accuracies compared to other analytical methods. Also, more sophisticated devices with half‐shadow adjustment and with quartz‐wedge compensation were already constructed in early times of polarimetry.

High improvement of polarimeters has been obtained with modern automated and semiautomated instruments. Until now, polarimetry has been the main analytical standard method for determining sucrose in the sugar and beverage industries and is an important tool for controlling production processes of optically active substances. For obtaining high precision and accuracy, the brightness and monochromaticity of the light source is important.

While polarimetry is based on intrinsic optical activity, polarization spectroscopy also measures anisotropies that may be induced into isotropic atomic or molecular species by DC electric or magnetic fields or also by interaction with radiation. Doppler‐free methods of nonlinear polarization spectroscopy yield high spectral resolution and result in the suppression of interferences by extremely close‐lying lines. Polarization spectroscopy based on an applied DC magnetic field, which is also denoted as coherent forward scattering spectroscopy (CFS), allows simultaneous multielement determination in combination with continuum light sources and the measurement over an extremely wide dynamic range.
Remote Sensing
Authors: Zalewski Edward F.
Published: July 2004

Remote Sensing is defined for space‐borne and airborne imaging instruments that use electromagnetic radiation. The historical background for this field of study is presented. The methods of remote sensing are described along with the portions of the electromagnetic spectrum that are utilized. The role of the atmospheric transmission limits and the corrections necessary for optimum accuracy is described. The different types electromagnetic detectors are described along with the image collection systems in which they are used. Modern remote sensing is possible because of the improvement in the accuracy of the radiometric calibration and characterization of the sensors and these methods are briefly described. The objective of remote sensing is the quantitative interpretation of the images, specifically obtaining the data products. Several examples of the basis for some of the data products are presented. Some of the remote sensing systems presently in use are briefly described. The future of remote sensing is described in terms of some of the planned sensors systems and the challenges that must be met in order to understand the Earth and mankind's effect on its climate.
Spectroscopy, Laser
Authors: Inguscio Massimo , Sasso Antonio
Published: July 2004

The high intensity, high spectral purity, and short‐pulse duration of laser sources have opened a new era in laser spectroscopy. Many sophisticated spectroscopic techniques have been developed during the last decades. They have allowed the investigation of the structure of atoms and molecules with great detail, making it possible to test fundamental quantum mechanics theories. Moreover, laser spectroscopy represents a very diffused tool in many other fields. A wide range of applications concern not only free atoms and molecules but also plasma physics and solid‐state physics and many other interdisciplinary fields such as chemistry, biology, and medicine. Laser spectroscopy is till now a very fascinating field of research continuously in evolution: the new techniques of laser cooling have allowed the production of condensates of atoms that represent a new state of the matter only recently explored.
Electrophotographic Copying and Printing (Xerography)
Authors: Hays Dan A. , Ossman Kenneth R.
Published: July 2004

In the electrophotographic process for copying and printing documents, the image content controls the amount of light that selectively discharges a uniformly charged photoreceptor material. The electrostatic image is developed with a charged, pigmented powder that is transferred and bonded to paper with heat and pressure. Over the years, a variety of optical devices and systems have been used as electrophotographic technology has evolved to higher levels of performance and image quality. The earlier copiers utilized a light source and lens optical system to project the document image onto the charged photoreceptor. The imagers for copying use either optics with moving components or flash exposure systems. Electrophotographic printers do not use direct optical imaging but use a digital stream from an external source to generate a printed document. These printers were enabled by advances in digital electronics and light sources that exposed the photoreceptor with a scanning laser beam modulated by digital signals. Alternatively, many electrophotographic printers in recent years utilize a Light Emitting Diode (LED) array and optical lens array to imagewise expose the photoreceptor. An electrophotographic printer combined with an image input scanner becomes a digital copier that provides image editing, multiple copies from a single document scan, and digital image processing for high‐quality color documents. The advances in imaging devices over the last half century have played an important role in the current achievement of high‐quality color electrophotographic documents.
Zeeman and Stark Effects
Authors: Silverman Mark P.
Published: July 2004

The Zeeman and Stark effects are modifications of spectral lines (displacements, splittings, and polarization changes) induced respectively by magnetic and electric fields. Application of an external static field splits the energy levels of a degenerate multiplet of states. In the Zeeman effect, levels shift up or down in energy depending on the magnitude and sign of the magnetic quantum number; in the Stark effect the shift depends only on the magnitude of the magnetic quantum number. Resulting spectral line patterns depend on the relative size of the field‐induced level splittings compared to the separation between different multiplets. This article discusses the weak‐, strong‐, and ultrastrong‐field Zeeman effects (the latter case arising when the magnetic interaction is comparable to the binding energy), and the linear and quadratic (including “ac”) Stark effects. In highly excited atoms (Rydberg atoms), where the separation between distinct manifolds is small and the electric polarizability enormous, the full range of Zeeman and Stark effects can be induced by relatively low fields. These effects have been employed to probe atomic and molecular structure, to measure inaccessible (e.g., stellar and interstellar) fields, and to gauge the influence of stray external fields in high‐precision metrology.
Stereoscopy
Authors: Claus Michael , Knupfer Klaus
Published: July 2004

This article covers the principles of stereoscopic imaging and measurements. It explains stereoscopic image‐generation techniques and the available methods of stereoimage display. 3D measurements in stereoimages and the related mathematics are explained, together with required hardware equipment and software. The generation of products such as digital elevation models, orthophotos and semiautomatic produced maps, resulting from the 3D measurements, is explained.
Photography, Physics and Technology
Authors: Schuster Norbert
Published: July 2004

After 150 years of development in photography, everybody can take good snapshots to remember by. The physical relationships involved in obtaining a sharp and well‐illuminated picture are presented here. Fine mechanical, optical, and electronic elements all work together in a modern photographic camera. The three mostly commonly used types of cameras, the viewfinder type, the Single Lens Reflex type, and the professional bellows camera, are explained in detail. All three types are used with classical film as well as in digital still cameras.
Image Processing of Optical Data
Authors: Petrou Maria
Published: July 2004

Image processing is concerned with the processing of digital images for the purpose of image enhancement, image restoration, image compression, and feature salienation so that the processed image can be viewed by a higher‐level computer vision module. These objectives are achieved by using linear and nonlinear methods. From the mathematical point of view, a digital image is a two‐dimensional array of numbers; so the linear methods used are based on linear algebra. The nonlinear methods used are various types of thresholding as well as methods based on statistics and probability.
Optical Aberrations
Authors: Turner Mary G.
Published: July 2004

A spherical wave front propagating through the optical system, by the time it exits the system, is often no longer perfectly spherical. The departure of any wave front that is exiting the optical system from the ideal spherical reference can be described by an aberration function. The aberration function can be expressed in the form of different polynomials. The optical system that introduces aberrations does not form a stigmatic or ideal image. The distribution of energy at the image surface for different wave front aberrations can be described by ray aberration functions. Wave and ray aberrations are closely related. This article presents the basics optical aberrations, commonly expressed in these two forms.
Optical Alignment
Authors: Ruda Mitchell C.
Published: July 2004

The philosophical approach to the alignment of optical systems is discussed. Methods of diagnosing the alignment errors through the observation of the actual image errors in the optical system are summarized. Some of the tools used in the alignment of optical systems are described. Important techniques are reviewed.
Optical Radiation Sources and Standards
Authors: Diedrich Jonathan , Dodds John
Published: July 2004

Artificial visible and near‐visible electromagnetic radiation is produced and characterized in several different ways. From incandescent light bulbs and gas‐discharge lamps to LEDs and lasers, light sources have been evolving for years. This chapter describes the various ways that light is produced as well as standardized. The first section discusses some of the different types of sources of radiation. Illustrated along with the different sources are examples of their uses. With all these sources, standardization and calibration are very important. The second section will discuss how, along with improved technology, the methods and procedures used to realize standards have evolved. Discussed is the evolution of radiation standards leading to the current method of realizing them. In addition, we discuss the methods used to calibrate optical devices using these standards.
An analysis of marketed surplus response of cereals in Haryana State of India
Authors: Goyal S.K. , Berg Ernst
Published: July 2004

This report uses a model that considers the effect of both factor and output prices on marketed surplus. To derive input demand and output supply elasticities, the normalized quadratic profit function and demand equations were estimated jointly with the seemingly unrelated regressions (SUR) estimation technique using farm level panel data. The data confirm the theoretical framework. The derived price elasticities of input demand, output supply, and marketed surplus have been simulated to examine alternative price policies for securing different levels of marketed surplus. At the observed price structure, the marketed surplus of wheat will increase almost equal to population growth, but in case of paddy it will grow at a very low rate. The study further reveals that besides price adjustment, technological improvement and non‐price factors are also of critical importance for increasing output supply and, hence, marketed surplus. [EconLit citations: Q120, C330.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 253–268, 2004.
Demand for nonalcoholic beverages: The case of low‐income households
Authors: Yen Steven T. , Lin Biing‐Hwan , Smallwood David M. , Andrews Margaret
Published: July 2004

Household beverage consumption is investigated using data from the National Food Stamp Program Survey conducted in the United States. A censored Translog demand system is estimated with the full‐information maximum‐likelihood procedure. All own‐price effects are negative and significant, and whole milk, reduced‐fat milk, juice, coffee, and tea are found to be net substitutes for soft drink. Thus, prices provide a partial answer to the declining consumption of milk and rising consumption of soft drink. Nutrition information and dietary beliefs also play important roles, highlighting the importance of an effective nutrition education program directed toward the low‐income households. [JEL citation: C34 (Truncated and Censored Models), D12 (Consumer Economics: Empirical), Q18 (Agricultural Policy; Food Policy).] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 309–321, 2004.
Generalized electrolyte‐NRTL model for mixed‐solvent electrolyte systems
Authors: Chen Chau‐Chyun , Song Yuhua
Published: July 2004

A generalized electrolyte Non‐Random Two‐Liquid (eNRTL) model proposed by Chen and coworkers is presented as a comprehensive excess Gibbs energy expression to represent the liquid‐phase nonideality for aqueous and mixed‐solvent electrolyte systems over the entire concentration range from pure solvents to saturated solutions or fused salts. The eNRTL model is used to correlate mean ionic activity coefficients of mixed‐solvent electrolyte systems. The segment interaction concept provides the framework necessary to represent the attractive interaction of ions with the hydrophilic segments of organic solvents and the repulsive interaction of ions with the hydrophobic segments of organic solvents. The ability to explicitly account for such distinctly different ion–segment interactions is shown to be the key for quantitative correlation of mean ionic activity coefficients in mixed‐solvent electrolyte systems. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1928–1941, 2004
Effect of the solid phase on the global phase behavior of Lennard–Jones mixtures
Authors: Attwood Brian C. , Hall Carol K.
Published: July 2004

Complete phase diagrams, that is, showing the solid, liquid, and vapor phases, are calculated for 29 binary mixtures of Lennard–Jones molecules characterized by different sets of interaction parameters using the Gibbs–Duhem integration technique. The impact of including the possibility of a solid phase on the global phase behavior of such mixtures is investigated by comparing the complete phase behavior calculated by simulation to the global phase diagram calculated from a fluid‐phase‐only equation of state. Complete phase diagrams from each region of the global phase diagram are presented and compared with the fluid‐phase‐only phase behavior for the same mixture. It is found that for mixtures in which the components have greatly dissimilar critical temperatures, the presence of the solid phase significantly alters the fluid‐phase equilibria. In those cases, the phase behavior classification based on experimental observations should differ from that predicted by an equation‐of‐state approach. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1948–1960, 2004
Effects of free convection on three‐dimensional protein transport in hollow‐fiber bioreactors
Authors: Łabȩcki Marek , Piret James M. , Bowen Bruce D.
Published: July 2004

A three‐dimensional analysis of protein redistribution in the extracapillary space (ECS) of ultrafiltration membrane hollow‐fiber bioreactors (HFBRs), used for mammalian cell culture, is presented. Homogeneous distribution of growth‐factor proteins in the ECS is essential for a successful startup and efficient operation of HFBRs. The ECS protein transport under most startup conditions of practical interest is strongly influenced by gravity and represents a complex interaction of forced‐ and free‐convective phenomena. These effects were investigated using a comprehensive porous medium model (PMM) that accounts for local variations of fluid density, fluid viscosity, and osmotic pressure resulting from time‐dependent changes in the protein concentration field. In addition, the model considers the influence of fiber‐free manifolds, which are adjacent to the fiber bundle and are accessible to ECS proteins and cells. The PMM predictions of the ECS protein distributions at different bioreactor orientations were in good agreement with the observed distributions of a colored test protein in an experimental HFBR cartridge. The results of this study can provide useful insights for optimizing HFBR operation strategies. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1974–1990, 2004
Development of an electrochemical cell for efficient hydrogen production through the IS process
Authors: Nomura Mikihiro , Nakao Shin‐ichi , Okuda Hiroyuki , Fujiwara Seiji , Kasahara Seiji , Ikenoya Kazuhiko , Kubo Shinji , Onuki Kaoru
Published: July 2004

The Bunsen reaction (SO2 + I2 + 2H2O = H2SO4 + 2HI) was examined by an electrochemical cell featuring a cation‐exchange membrane as the separator, using sulfuric acid dissolving sulfur dioxide as the anolyte and hydriodic acid dissolving iodine as the catholyte. In galvanostatic electrolysis, the molality of H2SO4 in the anolyte and that of HI in the catholyte were increased up to 17.8 and 14.9 mol kgH2O−1, respectively. These concentrations were far higher than those that were obtained by the Bunsen reaction carried out in the presence of a large amount of iodine (such as I2/HI = 4). I2 concentration after the concentration procedure was at I2/HI = 0.95, which is lower than the reported value. I2 is one of the recycling agents in the IS process. HI and H2SO4 were successfully concentrated under low I2 concentration. The concentration of HI agreed with the calculated value, based on the amount of electricity consumed, indicating high current efficiency. Heat/mass balance using this type of electrochemical cell through the IS process is discussed for evaluation of the reactor. The thermal efficiency to produce hydrogen was calculated at 42.1%, without heat recovery for electricity, by optimizing HI and H2SO4 concentrations after application of the electrochemical cell. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1991–1998, 2004
Subtelomeric deletions of chromosome 9q: A novel microdeletion syndrome
Authors: Stewart Douglas R. , Huang Alina , Faravelli Francesca , Anderlid Britt‐Marie , Medne Livija , Ciprero Karen , Kaur Maninder , Rossi Elena , Tenconi Romano , Nordenskjöld Magnus , Gripp Karen W. , Nicholson Linda , Meschino Wendy S. , Capua Esther , Quarrell Oliver W.J. , Flint Jonathon , Irons Mira , Giampietro Philip F. , Schowalter David B. , Zaleski Christina A. , Malacarne Michela , Zackai Elaine H. , Spinner Nancy B. , Krantz Ian D.
Published: July 2004

Fluorescent in situ hybridization (FISH) screening of subtelomeric rearrangements has resulted in the identification of previously unrecognized chromosomal causes of mental retardation with and without dysmorphic features. This article reports the phenotypic and molecular breakpoint characterization in a cohort of 12 patients with subtelomeric deletions of chromosome 9q34. The phenotypic findings are consistent amongst these individuals and consist of mental retardation, distinct facial features and congenital heart defects (primarily conotruncal defects). Detailed breakpoint mapping by FISH, microsatellite and single nucleotide polymorphism (SNP) genotyping analysis has narrowed the commonly deleted region to an approximately 1.2 Mb interval containing 14 known transcripts. The majority of the proximal deletion breakpoints fall within a 400 kb interval between SNP markers C12020842 proximally and C80658 distally suggesting a common breakpoint in this interval. © 2004 Wiley‐Liss, Inc.
Kubische flüssigkristalline Nanopartikel
Authors: Yang Da , Armitage Bruce , Marder Seth R.
Published: July 2004

Kubische flüssigkristalline Nanopartikel, die aus wässrigen Dispersionen kubischer Lipid‐Wasser‐Phasen hergestellt werden, sind bei Anwesenheit bestimmter Dispersionsmittel kinetisch stabil. Die Eigenschaften kubischer Nanopartikel aus Monoolein‐Wasser‐ und anderen Lipid‐Wasser‐Systemen wurden mit verschiedenen experimentellen Techniken untersucht. Die kubischen Nanopartikel können durch die Polymerisation reaktiver Lipide in den kubischen Lipidsystemen stabilisiert werden. Zur einfacheren Herstellung und Anwendung kubischer Nanopartikel wurden verschiedene energiesparende Methoden entwickelt. Kubische Nanoparkikel sind wegen ihrer Fähigkeit, lipophile, amphiphile und hydrophile Moleküle gesteuert aufzunehmen und abzugeben, sowie ihrer guten Biokompatibilität hervorragende Kandidaten für die Anwendung beim Transport von Wirkstoffen.
Cu(II)‐incorporated, histidine‐containing, magnetic‐metal‐complexing beads as specific sorbents for the metal chelate affinity of albumin
Authors: Akgöl Sinan , Türkmen Deniz , Denizli Adil
Published: July 2004

N‐Methacryloyl‐(L)‐histidine methyl ester (MAH) was synthesized from metharyloyl chloride and histidine. Spherical beads with an average size of 150–250 μm were obtained by the suspension polymerization of ethylene glycol dimethacrylate and MAH in an aqueous dispersion medium. Magnetic poly(ethylene glycol dimethacrylate‐co‐N‐Methacryloyl‐(L)‐histidine methyl ester) [m‐p(EGDMA‐co‐MAH)] microbeads were characterized with swelling tests, electron spin resonance, elemental analysis, and scanning electron microscopy. The specific surface area of the beads was 80.1 m2/g. m‐p(EGDMA‐co‐MAH) microbeads with a swelling ratio of 40.2% and 43.9 μmol of MAH/g were used for the adsorption of bovine serum albumin (BSA) in a batch system. The Cu(II) concentration was 4.1 μmol/g. The adsorption capacity of BSA on the Cu(II)‐incorporated beads was 19.2 mg of BSA/g. The BSA adsorption first increased with the BSA concentration and then reached a plateau, which was about 19.2 mg of BSA/g. The maximum adsorption was observed at pH 5.0, which was the isoelectric point of BSA. The BSA adsorption increased with decreasing temperature, and the maximum adsorption was achieved at 4°C. High desorption ratios (>90% of the adsorbed BSA) were achieved with 1.0M NaSCN (pH 8.0) in 30 min. The nonspecific adsorption of BSA onto the m‐p(EGDMA‐co‐MAH) beads was negligible. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2669–2677, 2004
Novel diols containing ester and amide groups and resulting poly(ester amide ester)s
Authors: Mehdipour‐Ataei Shahram , Einollahy Parvin
Published: July 2004

The reaction of terephthaloyl chloride and 4‐hydroxybenzoic acid resulted in terephthalyl bis(4‐oxybenzoic) acid. This diester diacid was converted into its corresponding diester diacid chloride (terephthaloyl dioxydibenzoylchloride) via a reaction with thionyl chloride. Diols with preformed ester and amide groups were prepared through the reaction of terephthaloyl dioxydibenzoylchloride with 4‐aminophenol and 5‐amino‐1‐naphthol. Polycondensation reactions of the prepared diols with different aromatic and aliphatic diacid chlorides afforded eight aromatic and semiaromatic poly(ester amide ester)s. The polymers were fully characterized, and their physical and thermal properties were studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2699–2703, 2004
Impact and relevance of LIS journals: A scientometric analysis of international and German‐language LIS journals—Citation analysis versus reader survey
Authors: Schloegl Christian , Stock Wolfgang G.
Published: July 2004

The goal of the scientometric analysis presented in this article was to investigate international and regional (i.e., German‐language) periodicals in the field of library and information science (LIS). This was done by means of a citation analysis and a reader survey. For the citation analysis, impact factor, citing half‐life, number of references per article, and the rate of self‐references of a periodical were used as indicators. In addition, the leading LIS periodicals were mapped. For the 40 international periodicals, data were collected from ISI's Social Sciences Citation Index Journal Citation Reports (JCR); the citations of the 10 German‐language journals were counted manually (overall 1,494 source articles with 10,520 citations). Altogether, the empirical base of the citation analysis consisted of nearly 90,000 citations in 6,203 source articles that were published between 1997 and 2000. The expert survey investigated reading frequency, applicability of the journals to the job of the reader, publication frequency, and publication preference both for all respondents and for different groups among them (practitioners vs. scientists, librarians vs. documentalists vs. LIS scholars, public sector vs. information industry vs. other private company employees). The study was conducted in spring 2002. A total of 257 questionnaires were returned by information specialists from Germany, Austria, and Switzerland. Having both citation and readership data, we performed a comparative analysis of these two data sets. This enabled us to identify answers to questions like: Does reading behavior correlate with the journal impact factor? Do readers prefer journals with a short or a long half‐life, or with a low or a high number of references? Is there any difference in this matter among librarians, documentalists, and LIS scholars?
Wasserundurchlässige Bauwerke aus Beton
Authors: Timm Günter
Published: July 2004

Die Anwendung des WU‐Betons ist durch die neue DAfStb‐Richtlinie geregelt. Für die Praxis bedeutet dies, Betonbauwerke wasserundurchlässig herzustellen und die hohen Kosten einer Schwarzabdichtung zu vermeiden. Voraussetzung ist eine klare Festlegung der Raumnutzung, um auf der Grundlage der Beanspruchung Betongüte, Bewehrungsanordnung, Fugenausbildung, Betonierverlauf und Nachbehandlung festzulegen. Eine einwandfreie Ausführung läßt sich nur erreichen, wenn die Qualitätssicherungskette vollständig abgearbeitet wird. Die Austrocknung des Betons und die Wasserdampfdiffusion sind bei der späteren Nutzung zu berücksichtigen.
Berechnung der Ersatzwanddicken von Aussteifungselementen mit Öffnungen
Authors: Küttler Matthias
Published: July 2004

Beim Nachweis von Aussteifungssystemen treten regelmäßig Sonderfälle der technischen Biegelehre auf, auf deren Auswirkungen aufmerksam gemacht wird. Es wird eine Bewehrung als Stabwerk unter Berücksichtigung der Schubverformung empfohlen. Die Auswirkungen der Vernachlässigung von mitwirkenden Riegelbereichen werden an einem Beispiel gezeigt.
Bauteile aus Stahlbeton unter Zugbeanspruchung
Authors: Keuser Manfred , Purainer René , Brunner Sebastian
Published: July 2004

Stahlbetonflächentragwerke erfahren in der Zugzone häufig zweiaxiale Zugbeanspruchungen, wie z. B. bei zweiaxial gespannten Deckenplatten, bei Fahrbahnplatten von Brücken mit Plattenbalken‐ oder Hohlkastenquerschnitt und im Einleitungsbereich von Einzellasten bei Stahlbetonplatten. Dabei ergibt sich eine gegenseitige Beeinflussung des Verbundverhaltens durch die senkrecht zur ihrerseits beanspruchten Bewehrung auftretenden Zugspannungen. Im Rahmen eines Forschungsprojektes wurde deshalb an einaxial auf Zug belasteten Versuchskörpern der Einfluß von bewehrungsparallelen Längsrissen auf die Verbundwirkung und das Last‐Verformungsverhalten untersucht. Auf der Grundlage der hier vorgestellten Versuchsergebnisse wurde ein einfaches Ingenieurmodell zur Beschreibung der Zusammenhänge entwickelt.
Framing heterosexism in lesbian families: a preliminary examination of resilient coping1
Authors: Litovich Marianna L. , Langhout Regina Day
Published: July 2004

The goals of this study are to examine the kinds of difficulties children face vis‐à‐vis heterosexism, how families help their children cope with these difficulties, and how coping leads to children's resilience. The experiences of six daughters of lesbian parents, ranging in age from 7 to 16, were empirically investigated through semi‐structured interviews with parents and children. Analysis included open and focused coding. Results suggest heterosexism is evident, but does not seem to negatively impact children's development. Themes include: how parents prepare their children to deal with heterosexism and how parents and children cope with incidents. Results elucidate the findings of previous studies, call for more qualitative research, and suggest future research directions. Copyright © 2004 John Wiley & Sons, Ltd.