bluuebunny/crossref_metadata_2025_split huggingface dataset:
Process engineering in biological aerobic waste‐water treatment
Authors: Gavrilescu M. , Macoveanu M. 
Published: December 2004

AbstractA non‐comprehensive review of several technical developments in the field of aerobic biological waste‐water treatment engineering is carried out, considering the active role the engineers have to play in this field. This paper brings together conventional and advanced problems in the field of aerobic biological waste‐water treatment.Such an overview of biological waste‐water treatment also precedes comments on some important aspects concerning the microorganisms responsible for waste‐water treatment as well as considerations of the application of fundamentals and kinetics to the analysis of the biological processes used most commonly for aerobic biological waste‐water treatment.A survey of the development of the biological activated‐sludge process and some modifications are given. Some problems implied in the conventional activated‐sludge waste‐water treatment are analyzed, considering conventional processes and bioreactor models (the continuous stirred‐tank reactor model and the plug‐flow reactor models of the activated‐sludge process) as well as aerated lagoons.Further, modifications of the activated‐sludge process are presented. These include additional details on the bioreactor progress and applications, with emphasis on aspects concerning airlift bioreactors and their variants, deep‐shaft bioreactors and reciprocating jet bioreactors which are considered as the third generation of bioreactors owing to their important advantages in design, operation and performance in waste‐water treatment. Sequencing‐batch reactors and aerobic digestion processes, including conventional aerobic digestion, high‐purity oxygen digestion, thermophilic aerobic digestion and cryophylic aerobic digestion are also reviewed.Finally, some aspects regarding the operational factors that are involved in the selection of the reactor type are included.
Investigation of aerobic degradation kinetics of surfactants using respirometric batch experiments
Authors: Schreiner A. , Asmussen C. , Wiesmann U. , Stan H.‐J. 
Published: December 2004

AbstractThe mineralization of a non‐ionic alcohol ethoxylate (AEO) surfactant was investigated over the concentration range occurring in rinsing water from surfactant production processes. For this, an experimental set‐up for respirometric batch experiments was developed. The set‐up and the method were validated by experiments with glucose as the single carbon source. It was possible to calculate substrate decay from the time course of exogenously consumed oxygen during respirometric batch experiments. The kinetic coefficients calculated by respirometry showed a lower standard deviation than those calculated from emasured glucose concentrations.The degradation mechanism of AEO was investigated by identification of metabolities, occurring during the mineralization process of AEO, using Flow Injection Mass spectrometry (FI‐MS). It was concluded that the degradation of AEO occurs in two main steps. First, the enzymatic hydrolysis of AEO into alcohol and polythylene glycol (PEG) is performed. Second, the mineralization of both substances takes place, while the mineralization of the alcohol is faster than that of the PEG. The mineralization kinetics were investigated in respirometric batch experiments. The model used is based on double MONOD kinetics for the substrates being produced by hydrolysis (μmax1 = 0.047 h−1, Ks1 = 15 mg/l DOC for alcohol; μmax2 = 0.027 h−1, KS2 = 4 mg/l DOC for PEG). The validation of the model by calculating the results obtained from measurements in a continuously operated lab scale CSTR with bacteria recycle was successful.
Increased enzymatic activities and levels of superoxide anion and phenolic compounds in cultures of basidiomycetes after temperature stress
Authors: Fink‐Boots M. , Malarczyk E. , Leonowicz A. 
Published: December 2004

AbstractSelected strains of basidiomycetes (Abortiporus biennis, Trametes versicolor and Cerrena unicolor) were shown to produce enhanced extracellular peroxidase (EP), superoxide dismutase (SOD) and laccase activities following the exposure of 10‐day‐old fungal cultures to separate high and low temperature stress. The stressful conditions also caused an increase in the concentrations of phenol compounds and superoxide anion radicals in these cultures. At first, peroxidase activity was observed at 12 hours from the moment of temperature stress application. Laccase activity appeared at 96 hours after the maximum levels of superoxide anion radicals (48 h) and SOD activity (36–72 h). The concentration of phenolic substances grew steadily during the period of cultivation. These relations between laccase, SOD and EP as well as superoxide radicals and phenol levels in the environment of ligninolytic fungi seems to be important in the course of the biosynthesis or biodegradation of lignin, as the consequence of adaptation of these basidiomycetes to environmental temperature conditions.
Optimization of some parameters of solid state fermentation of wheat bran for protease production by a local strain of Rhizopus oryzae
Authors: Aikat K. , Bhattacharyya B. C. 
Published: December 2004

AbstractSome parameters of the production of an alkaline protease by Rhizopus oryzae in the solid state fermentation of wheat bran were optimized. Using the optimum parameters of an inoculum age of 7 days, an incubation time of 9 days, an amount of CZAPEK‐DOX (liquid medium) of 6 ml/g bran and an incubation temperature of 33°C, an activity of 50 U/g bran was achieved. The initial pH of the CZAPEK‐DOX medium had little effect. Re‐incubation of mouldy bran with only fresh CZAPEK‐DOX yielded 3 times total activity compared to single‐cycle fermentation. As for the effect of the amount CZAPEK‐DOX medium, the water constituent contributed more to activity increase than did the salt component. The ARRHENIUS activation energies were 23 and 7.9 kcal/mole below and above the optimum of 33°C, respectively. In all the studies, along with protease production, variation of protein content and specific activity were also observed. Attempts were made to explain the effects and also gauge their implications for large‐scale production.
Modeling organic surfaces with self‐assembled monolayers
Authors: Bain Colin D. , Whitesides George M. 
Published: December 2004

AbstractThe interfacial properties of organic materials are of critical importance in many applications, especially the control of wettability, adhesion, tribology, and corrosion. The relationships between the microscopic structure of an organic surface and its macroscopic physical properties are, however, only poorly understood. This short review presents a model system that has the ease of preparation and the structural definition required to provide a firm understanding of interfacial phenomena. Long‐chain thiols, HS(CH2)nX, adsorb from solution onto gold and form densely packed, oriented monolayers. By varying the terminal functional group, X, of the thiol, organic surfaces can be created having a wide range of structures and properties. More, complex systems can be constructed by coadsorbing two or more thiols with different terminal functional groups or with different chain lengths onto a common gold substrate. By these techniques, controlled degrees of disorder can be introduced into model surfaces. We have used these systems to explore the relationships between the microscopic structure of the monolayers on a molecular and supramolecular scale and their macroscopic properties. Wettability is a macroscopic interfacial property that has proven of particular interest.
Solid State NMR spectroscopy in polymer science
Authors: Blümich Bernhard , Hagemeyer Alfred , Schaefer Dieter , Schmidt‐Rohr Klaus , Spiess Hans W. 
Published: December 2004

AbstractThe properties of solid polymers are determined to a large extent by the structure, order, and dynamics of the molecules which make up the polymers on a molecular scale as well as by the morphological domain structure involving the size and type of crystalline, amorphous and interfacial phases. Solid state NMR spectroscopy is a method particularly suited to the investigation of the properties of individual molecules since their resonance frequency depends on the structure and on the orientation of a molecular segment in the magnetic field. In addition, morphological aspects can be studied by following the spin diffusion between individual phases. This review covers NMR techniques devised recently to address such polymer specific questions.
Electroceramics: Characterization by Impedance Spectroscopy
Authors: Irvine John T. S. , Sinclair Derek C. , West Anthony R. 
Published: December 2004

AbstractElectroceramics are advanced materials whose properties and applications depend on the close control of structure, composition, ceramic texture, dopants and dopant (or defect) distribution. Impedance spectroscopy is a powerful technique for unravelling the complexities of such materials, which functions by utilizing the different frequency dependences of the constituent components for their separation. Thus, electrical inhomogeneities in ceramic electrolytes, electrode/electrolyte interfaces, surface layers on glasses, ferroelectricity, positive temperature coefficient of resistance behavior and even ferrimagnetism can all be probed, successfully, using this technique.
Synthesis and properties of viologen functionalized poly(3‐alkylthienylenes)
Authors: Bäuerle Peter , Gaudl Kai‐Uwe 
Published: December 2004

Viologen functionalized conducting polymers synthesized from the substituted monomers whon in the figure are interesting materials with possible applications in redox or electrocatalysis, sensors, and electrochromic devices. Monomers and polymers with various numbers of methylene groups separating the thiophene units and the redoxactive viologen moieties have been synthesized and characterized.magnified image
Langmuir–blodgett films for electronic applications
Authors: Tieke Bernd 
Published: December 2004

AbstractThe present status of research on Langmuir‐Blodgett (LB) films is outlined in relation to specific properties for electronic applications. The fundamentals of LB films are briefly described such as preparation techniques, film types, structure, and suitable compounds for functional amphiphiles, unconventional film‐forming materials and polymers. Stress is laid on novel functional LB films exhibiting either photochemical and thermal reactivity, or electroactive properties such as electrical conduction, redox activity, electrochromism, nonlinear optical properties, and pyroelectric activity. The current status of LB films with regard to electronic applications is described, e.g. as photo‐ or e‐beam resists, information storage systems, barrier layers, chemisensors, frequency converters and modulators, optical switches, guided wave structures or infrared sensors. Prospects for future molecular electronic devices are also briefly discussed.
Solar induced hydrogen production in a semiconductor septum electrochemical photovoltaic cell
Authors: Tien H. Ti 
Published: December 2004

Seawater + visible light → electricity and hydrogen. This is the reaction which occurs in a solar cell recently developed by a group at the Michigan State University, based on an n‐type polycrystalline cadmium selenide (CdSe) electrode (see figure). The work is based on experience gained in research into membranes for artificial photosynthesis.
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Highly polarizable zwitter‐ions for nonlinear optics: Synthesis, structure and properties of phenoxide‐pyridinium derivatives
Authors: Bacquet Gérard , Bassoul Pierre , Combellas Catherine , Simon Jacques , Thiébault André , Tournilhac Francois 
Published: December 2004

High hyperpolarizabilities can be obtained in nonlinear optical materials through the incorporation of electron donor and acceptor moieties. This communication reports a convenient synthetic route (see figure) to materials containing both phenoxide and pyridinium units which are among the most favorbale gropus for this purpose. The hyperpolarizabilities are examnined and the crystal structure of 1 a is discussed.magnified image
Synthesis of molecular organometallic composites: Polymerization of vinylferrocene in a porous polymer matrix
Authors: Arshady Reza , Corain Benedetto , Lora Silvano , Palma Giancarlo , Russo Umberto , Sam Felix Okon , Zecca Marco 
Published: December 2004

Polymer‐organometallic composites are potentially suitable for catalyst development. 3.8% Fe has been incorporated into a composite (see figure) by the copolymarization of vinyl ferrocene, dimethylacrylamide and methylene bisacrylamide within a preformed porous polymeric matrix, a metal incorporation significantly higher than that reported for materials obtained by graft polymerization.magnified image
Protein interactions with ordered lipid films: Specific and unspecific binding
Authors: Ahlers Michael , Blankenburg Rainer , Haas Heinrich , Möbius Dietmar , Möhwald Helmuth , Müller Wolfgang , Ringsdorf Helmut , Siegmund Hans‐Ulrich 
Published: December 2004

Communication: Membrane‐bound receptors improtant in biochemistry and medicine can be modeled using mono‐ and multilayer amphiphilic LB films. Proteins bound to the films (see figure) can possess either enzymatic activity or a specific binding capability that can be used in biological tests. Here, the interactions between polypeptides such as cytochrome C, insulin, and concanavalin A, and several types of films are evaluated.
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Photosensitive polymeric amphiphiles: Irradiation‐induced structural changes in langmuir–blodgett multilayers
Authors: Arndt Thomas , Häußling Lukas , Ringsdorf Helmut , Wegner Gerhard 
Published: December 2004

Communication: Microstructure control in LB films, for example with lithography, is essential for potential applications in electronics. The photochemically induced reaction shown in the figure, where the highly ordered, densely packed film cleaves to form a cationic polymer (right) and a hydrophobic side chain (left) could be exploited to produce domainsized features on flood exposure with UV light.
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Organic Solar Cells
Authors: Wöhrle Dieter , Meissner Dieter 
Published: December 2004

Review: The conversion of sunlight into electricity can be achieved using a solar cell and is one of the most attractive future soruce of energy. Silicon‐based cells, while quite efficient, are difficult and expensive to produce, a fact that drives up the cost of electricity produced using them. The alternative, organic‐based cells (see Figure) have the potential advantages of ease of processing and cheapness if their efficiency can be brought up to reasonable levels. Recent progress made and future targets in this field are reviewed.
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Selective low‐temperature chemical vapor deposition of copper from (hexafluoroacetylacetonato)copper(I)trimethylphosphine, (hfa)CuP(Me)3
Authors: Kodas Toivo T. , Shin H.‐K. , Chi K.‐M. , Hampden‐Smith Mark J. , Farr John D. , Paffett Mark 
Published: December 2004

Communication: The deposition of smooth, dense, fine‐grained, low resistivity copper films has been achieved at temperatures as low as 150°C from an organometallic precursor. It is suggested that the films (see figure) are formed as the result of thermal disproportionation of the precursor without decomposition of the ligand. Substrate‐selective deposition at rates of over 1000 Åμmin is demonstrated.magnified image
Trisubstituted decacyclene derivatives: Bridging the gap between the carbonaceous mesophase and discotic liquid crystals
Authors: Keinan Ehud , Kumar Sandeep , Moshenberg Reuven , Ghirlando Rodolfo , Wachtel Ellen J. 
Published: December 2004

Communication: Discotic mesogens with C3 symmetry (see figure) are shown to form the basis of a chemically stable low‐temperature model for the carbonaceous mesophase, a key intermediate in the production of coke and graphite via the carbonization of organic precursors. The synthesis and properties are reported.magnified image
Ladder Polymers: The new generation
Authors: Schlüter Arnulf‐Dieter 
Published: December 2004

Review: Polymers with high thermal, mechanical, and chemical stabilitybased on a ladder‐type structure (see figure), have suffered in the past from insolubility or infusibility. A new strategy for the controlled synthesis of processible ladder polymers, based on Diels‐Alder polymerization is reviewed, and the polymers considered as precursors to graphite ribbons, materials predicted to have properties lying between graphite and single‐stranded polyacetylene.equation image
Molecular imaging by Raman microscopy
Authors: Batchelder David N. , Cheng Chunwei , David Pitt G. 
Published: December 2004

Research News: Raman microscopy combines the ability to indentify molecular species in a sample and to determine the location of these species within the sample. An example of the application of the technique is shown in the figure where a plasma‐deposited diamond film is imaged, the lighter areas indicating the presence of crystalline diamond. The developement of the technique and some of its applications are outlined.magnified image
Precursor compounds for organic metals and nonlinear optical devices from carbohydratederived hydroxymethylfurfuraldehyde:[1, 2] Furanoid electron donors and push/pull substituted compounds
Authors: Schöberl Ulrich , Salbeck Josef , Daub Jörg 
Published: December 2004

Non‐food applications of industrially accessible low‐molecular‐weight carbohydrates are examined. Available from, for example, sucrose, starch, or cellulose, the carbohydrates are shown to form the basis of conducting charge‐transfer salts or materials with nonlinear optical properties. The compound shown in the figure, for example, which is based on a furan unit obtainable from glucose, is shown to form a stable charge‐transfer salt with TCNQ exhibiting a powder conductivity of 10−2 S/cm at room temperature. magnified image
Microparticles from biodegradable polymers
Authors: Ahlers Michael , Krone Volker , Walch Axel 
Published: December 2004

Intelligent routes of delivery for pharmaceutical productss are provided by the application of biodegradable polymers. Microparticles formed from the polymers can be used to protect sensitive or unstable protein or peptide‐based drugs enabiling them to be delivered to the desired site in the body before being released. The microparticles can take on a number of shapes, an example of which is shown in the figure. magnified image
A ferroelectric liquid crystal dimer: Synthesis and properties
Authors: Marcos Mercedes , Omenat Ana , Serrano José Luis , Sierra Teresa , Ezcurra Amaya 
Published: December 2004

Chiral liquid‐crystalline phases are of great interest due to their nonlinear optical and ferroelectric properties. Side‐chain FLCPs (ferroelectric liquid crystal polymers) are known but no main chain FLCPs have been reported, only a limited number of FLC dimers which are used as models for the main chain compounds being known. Here, a new dimer is presented (see figure) which exhibits a high spontaneous polarization. magnified image
High‐power Nd:YAG lasers
Authors: Wittrock Ulrich 
Published: December 2004

The output power, efficiency, and beam quality of high‐powerd Nd: YAG lasers can be improved by employing a device configuration which improves pumping efficiency. By locating the pumping source within the cavity of a tube laser, the pumping radiation is forced to pass through the crystal more effectively thus increasing efficiency. magnified image
Polymerization of methyltrioxorhenium(VII) organometallic oxides as precursors for oxide ceramics
Authors: Herrmann Wolfgang A. , Fischer Richard W. , Scherer Wolfgang 
Published: December 2004

Polymerization by acid‐induced aggregation, a process that was previously unknown in organometallic chemistry, is shown to occur in methyltrioxorhenium(VII). The resulting polymer, an oxide ceramic precursor, undergoes an unusual depolymerization: in the weeks following compression of a pellet of the polymer, the surface becomes covered with large single crystals of the monomer (see figure). This is the first example of the specific crystallization of a metal‐organic compound from the solid state by application of pressure. magnified image
Anisotropic gels in liquid crystal devices
Authors: Hikmet Rifat A. M. 
Published: December 2004

Anisotropic gels are a novel type of material obtained by in situ polymerization of liquid crystal (LC) molecules in the presence of low molecular weight conventional LC molecules without reactive groups. The resulting anisotropic network (see figure) possesses the structure of the original LC mixture. These gels offer new possibilites for the manufacture of LC devices, including both active and passive optical components. magnified image
Extended homologues of tetrathioalkyl‐tetrathiafulvalenes
Authors: Müllen Klaus , Scherer Ute , Shen Yong‐Jia , Adam Martin , Bietsch Werner , Von Schütz Jost Ulrich 
Published: December 2004

Tetrathiafulvalene radical cation salts are organic‐based conductors where an increase of the dimensionality of the conducting process leads to a stabilization of the metallic state. Donor molecules of the type shown in the Figure should increase this dimensionality by extending the π conjugation of the system. The synthesis of the new donor and the electrical properties of its salts are presented. magnified image
Covalent binding of glucose oxidase to functionalized polyazulenes. The first application of polyazulenes in amperometric biosensors
Authors: Schuhmann Wolfgang , Huber Johanna , Mirlach Albert , Daub Jörg 
Published: December 2004

The covalent binding of enzymes to the surface of electrodes has been shown to lead to amperometric enzyme electrodes with fast response characteristics. New C‐2 substituted azulenes offer a viable alternative to the use of pyrrole derivatives as electrode materials as they easily form thin films of conducting polymeric material on electrochemical doping (see Figure). magnified image
Compound Semiconductor Ultrathin Films— characterization and control of growth
Authors: Inoue Naohisa 
Published: December 2004

The unprecedented control of ultra‐thin‐film properties required by advanced device concepts has led to the development of novel techniques for both growth and characterization, including cathodoluminescence microscopy, scanning tunneling microscopy and in situ optical diagnostics. In situ electron microscopy can be used to directly observe transient growth processes, revealing unexpected features such as the lateral growth of Ga layers around droplets when the surrounding surface is covered with As (Figure). magnified image magnified image
Computer‐Aided Materials Design for semiconductors
Authors: Ito Tomonori , Ohno Takahisa , Shiraishi Kenji , Yamaguchi Eiichi 
Published: December 2004

AbstractComputer‐aided materials design for semiconductors is reviewed. Reliable predictions are possible for a wide range of problems, such as the behavior of various heterovalent atomic species in III‐V semiconductors, including C (conduction type), Si (DX‐center), Ge (GaAs/Ge superlattices), S, Se and Te (passivation of GaAs surfaces), by using such computer‐aided calculation techniques as pseudopotential methods.
Effects of surface topology and highly anisotropic polymer LB films on liquid crystal alignment
Authors: Suzuki Masayoshi , Ferencz Andreas , Iida Shigeki , Enkelmann Volker , Wegner Gerhard 
Published: December 2004

Controlling molecular orientation, especially in liquid crystals, is of particular current interest for example in the development of display technology. Here it is shown, through studying various LCs (e.g. PCH5 or Oil red O, see figure) and orientation techniques, that the alignment of the polymer chains in the alignment layer plays the most important role in controlling the orientation of the liquid crystals. magnified image