bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of mechanical properties and interfacial adhesion of PP/EPDM/flax fiber composites using maleic anhydride as a compatibilizer
Authors: López Manchado M. A. , Arroyo M. , Biagiotti J. , Kenny J. M.
Published: June 2004

In order to improve the compatibility between natural fibers and polypropylene (PP) and polypropylene‐ethylene propylene diene terpolymer (PP‐EPDM) blends, the functionalization of both matrices with maleic anhydride (MA) is investigated in this study. The morphological observations carried out by scanning electron microscopy show that the incorporation of small amounts of functionalized polymer considerably improves the adhesion at the fiber‐matrix interface. In these cases, the fibers are perfectly embedded in the matrix in relation to the composites prepared with the pure homopolymers, and a significant increase in the composite strength is also observed, particularly, after the incorporation of both modified polymers (MAPP and MAEPDM). Thus, it is possible to correlate better interfacial adhesion with the improvement of mechanical properties. It is assumed that the functionalization of the matrix reduces interfacial stress concentrations and may prevent fiber‐fiber interactions, which are responsible for premature composite failure. The crystallization kinetics of PP were also analyzed by differential scanning calorimetry (DSC). It was observed that both flax fiber and rubber behave as effective nucleant agents, accelerating PP crystallization. Moreover, these results are particularly relevant when the grafted matrices are added to the composite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2170–2178, 2003
Synthesis and characterization of poly(N‐phenyl methacrylamide‐co‐methyl methacrylate) and reactivity ratios determination
Authors: Jayasimha Reddy G. , Venkata Naidu S. , Rami Reddy A. V.
Published: June 2004

Free‐radical solution copolymerization of N‐phenyl methacrylamide and methyl methacrylate in various feed ratios was done using a benzoyl peroxide initiator in N,N‐dimethylformamide at 70°C. The structure of the copolymer was elucidated by infrared and proton nuclear magnetic resonance spectroscopy. The copolymer composition was determined from the corresponding 1H‐NMR spectra of the copolymers. Finemann–Ross and Kelen–Tudos methods were used to determine the reactivity ratios of the monomers. The molecular weight distribution of the copolymers was determined using gel permeation chromatography. Thermal properties of the copolymers were determined using differential scanning calorimetry and thermogravimetric analysis (TGA). The activation energy for thermal degradation of the copolymers was determined from the TGA data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2179–2186, 2003
Gas‐sorption properties of 6FDA–durene/1,4‐phenylenediamine (pPDA) and 6FDA–durene/1,3‐phenylenediamine (mPDA) copolyimides
Authors: Cheng Si‐Xue , Chung Tai‐Shung , Wang Rong , Vora Rohit H.
Published: June 2004

We investigated the sorption isotherms of O2, N2, CH4, and CO2 gases in 6FDA–durene, 6FDA–1,4‐phenylenediamine (6FDA–pPDA), and 6FDA–1,3‐phenylenediamine (6FDA–mPDA) homopolymers and 6FDA–durene/pPDA and 6FDA–durene/mPDA copolyimides. The solubilities decrease in the order of the inherent condensabilities of the penetrant gases, namely, CO2, CH4, O2, and N2. The chemical structures of the polymer, as well as the chain packing, determine the sorption properties of these homopolymers and copolymers. The FDA–durene homopolymer has the highest solubility for all gases because of its high specific free volume and fractional free volume. The solubilities of the copolymers increase with an increasing 6FDA–durene content, while the solubility selectivities of the copolymers only vary slightly. The values of KD (Henry's law constant) and CH′ (Langmuir site capacity) of these copolyimides decrease with a decreasing 6FDA–durene content. To our surprise, contradictory to the previous known fact that the meta‐connected materials tend to have denser molecular packing than that of the para‐linked materials for homopolymers, the 6FDA–durene/mPDA 80/20 copolymer has higher gas solubilities than those of the 6FDA–durene/pPDA 80/20 copolymer. The random moiety sequence within the copolymer may be the main cause for the abnormal phenomenon. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2187–2193, 2003
Characterization of poly(trimethylene/butylene terephthalate) copolymer prepared by the copolycondensation of bis(3‐hydroxypropyl terephthalate) and bis(4‐hydroxybutyl terephthalate)
Authors: Kim Joon Ho , Park Jun Ho , Jang Ho Kyu , Yoon Ji Young , Lyoo Won Seok
Published: June 2004

Homopolymers and copolymers were synthesized by polycondensation and copolycondensation, with varying feed ratios of bis(3‐hydroxypropyl terephthalate) (BHPT) and bis(4‐hydroxybutyl terephthalate) (BHBT) at 270°C. In addition, in the mol ratio of 1:1, copoly(trimethylene terephthalate/butylene terephthalate) [P(TT/BT)], with reaction times of 5, 10, 20, 30, and 60 min, was synthesized to identify the chain‐growth process of the copolymers. From differential scanning calorimetry (DSC) data, it was found that a random copolymer might be formed during copolycondensation. The molecular structure of copolymers, formed through the interchange reaction of BHPT and BHBT, was investigated using carbon nuclear magnetic resonance spectroscopy (13C‐NMR). We calculated the sequence‐length distributions of trimethylene and butylene sequences and randomness in the copolymers using 13C‐NMR data. From the values of the number‐average sequence length calculated, it was determined that a random copolymer was produced: This result coincides with previous DSC data. The lateral spacing of the unit cell of the copolymer increased slowly when the mol percent of one monomer was increased to that of the other monomer, indicating broadening of the unit cell by lateral distortion. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2200–2205, 2003
Thermal degradation kinetics of isotactic and atactic polypropylene
Authors: Kumar Ravi , Madras Giridhar
Published: June 2004

The thermal degradation of isotactic and atactic polypropylene was investigated in bulk and in solution. The degradation in bulk was studied with thermogravimetric analysis, and the degradation in solution was studied by the dissolution of the polymer in paraffin oil. The degradation in solution was investigated from 230 to 350°C. The effect of the hydrogen donor on the degradation of the polymer in solution was also studied at 350°C. Continuous distribution kinetics were employed to model the degradation kinetics for the degradation in solution. The rate coefficients were obtained, and the activation energy was calculated from an Arrhenius plot. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2206–2213, 2003
Thermoreversible hydrogels. XVIII. Synthesis, swelling characteristics, and diffusion behaviors of porous, ionic, thermosensitive hydrogels
Authors: Lee Wen‐Fu , Chiu Ru‐Jen
Published: June 2004

Porous, ionic, thermosensitive hydrogels were prepared from N‐isopropylacrylamide, a cationic monomer [trimethyl (acrylamido propyl) ammonium iodide (TMAAI)], an anionic monomer [acrylic acid (AA)], a zwitterionic monomer [N′,N′‐dimethyl (acrylamido propyl) ammonium propane sulfonate], or a nonionic monomer [poly(ethylene glycol) methyl ether acrylate], and a pore‐forming agent [poly(ethylene glycol) (PEG)] of different molecular weights. Some fundamental properties and dynamic swelling kinetic parameters and solute permeation for these porous gels were investigated. The results showed that the gel containing the cationic monomer TMAAI had a higher equilibrium swelling ratio. The diffusion coefficients showed that the swelling rates for the gels with the anionic monomer AA and PEG with a higher molecular weight (20,000) were faster. The results showed that the fast swelling–deswelling behavior for the porous structure gels was due to them being more available than the gels with long hydrophilic side chains. In addition, the interactive force between the solutes and gels and the solute permeation through the porous gels were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2214–2223, 2003
Kinetic study of the curing behavior of bismaleimide modified with diallylbisphenol A
Authors: Xiong Y. , Boey F. Y. C. , Rath S. K.
Published: June 2004

The curing kinetics of bismaleimide modified with diallylbisphenol A were investigated for different ratios of 1,1′‐(methylene di‐4,1‐phenylene) bismaleimide and diallylbisphenol A with differential scanning calorimetry. Multiheating‐rate and isothermal methods were used to study the kinetics of the curing process. The results indicated that the activation energy changed with the extent of conversion. The activation energy obtained by the multiheating‐rate method was higher than that obtained by the isothermal method. Two kinetic models (autocatalytic and nth‐order) were successfully used to model the curing process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2229–2240, 2003
Preparation and swelling properties of solution crosslinked poly(cis‐1,4‐butadiene) gels
Authors: Qi Zhang Gao , Hua Zhou Mei , Hong Ma Jing , Liang Bo Run
Published: June 2004

Poly(cis‐1,4‐butadiene) (PCB) gels were prepared by the crosslinking polymerization of 4‐tert‐butylstyrene (tBS) and divinylbenzene (DVB) onto unvulcanized butadiene rubber with a solution polymerization technique with benzoyl peroxide (BPO) as an initiator. The effects of the reaction conditions, such as the amount of the solvent, the amount of DVB and tBS, and the initiator (BPO), on the equilibrium swelling ratio (Qe) were also investigated. The highest oil absorbencies of crosslinked gels in xylene and cyclohexane were 51.35 and 32.98 g/g, respectively. A swelling kinetic equation was proposed for this system: Qt = Qe − {Kt + [1/(Qe − Q0)]}−1, where Qt is the swelling ratio at time t, Q0 is the initial swelling ratio, and K is the swelling kinetic constant. This equation fit the experimental results quite well. The diffusion of organic solvents in PCB gels was Fickian. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2241–2245, 2003
Pervaporation performance of PTMSP membranes at high temperatures
Authors: González‐Velasco Juan R. , López‐Dehesa Cristina , González‐Marcos José A.
Published: June 2004

The separation of ethanol–water mixtures by pervaporation has been carried out through poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) membranes. This polymer is known to be alcohol‐selective and shows high selectivity and ethanol permeation rate. The performance of this polymer was studied at high temperatures over long periods of time to examine deterioration of its transport properties. The PTMSP membrane shows an initial separation factor (α) of about 10.7 and specific permeation rate (R) of 0.054 g m m−2 h−1 for a 10 wt % ethanol solution. Although this polymer has good characteristics for the separation of gases and liquid mixtures, its selectivity decreases with operating time, reaching a value of 8 after 450 h. On the other hand, the specific permeation rate remains almost constant except during the swelling period, in which it decreases to a value of 0.035 g m m−2 h−1. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2255–2259, 2003
Synergistic effect of dual rubber system in toughening styrene maleic anhydride copolymers
Authors: Wang Rongwei , Wang Wei
Published: June 2004

Styrene maleic anhydride (SMA) copolymers were toughened by blending with two distinctly different rubber modifiers: styrene‐butadiene‐styrene (SBS) block copolymer and methacrylated butadiene‐styrene emulsion‐made graft copolymer (MBS). The modifiers were used both individually and in combination for the examination of their roles in toughening SMA. SMA was miscible with poly(methylmethacrylate) shell of MBS, whereas it was partially miscible with the polystyrene (PS) phase of SBS. When 40–50% of SBS was used in blends, the PS phase of SBS became immiscible with SMA. SBS did not improve the Izod impact strength of SMA appreciably. A prominent synergistic toughening effect was experimentally observed when SBS and MBS were used in combination in brittle SMA. This effect may be attributed to the fact that the large SBS particles initiate crazes and small MBS particles with good adhesion to SMA matrix improve the ligament thickness, which may play a critical role in craze growth and termination. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2260–2267, 2003
Influence of elastomer distribution on the cryogenic microcracking of carbon fiber/epoxy composites
Authors: Nobelen Matthieu , Hayes Brian S. , Seferis James C.
Published: June 2004

Carbon fiber/epoxy laminates containing three different types of rubber modifiers, separately and in combination, were developed for testing in a cryogenic environment. Preformed rubber particles, core shell rubber, and solid carboxyl‐functionalized rubber were chosen as additives to a model prepreg matrix to control the placement of the rubber within the resulting laminates. Cryogenic microcracking and mode I and II fracture toughness and interlaminar shear strength experiments were performed. Scanning electron microscopy was used to observe fracture surfaces of the rubber‐modified laminates. Fracture toughness properties were improved while the ILSS decreased because of the presence of these rubber modifiers. It was observed that the presence of these modifiers significantly reduced the microcrack density of the laminates exposed to cryogenic cycling, and in the case of one, even eliminated microcracking entirely. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2268–2275, 2003
Studies on thermal activities of fabrics treated by polyethylene glycol
Authors: Ma XiaoGuang , Guo HaoJie
Published: June 2004

In this study, the special adjusting‐temperature function of polyethylene glycol (PEG) with low molecular weight was introduced. PEGs and a two‐group mixing system of PEGs of different molecular weights were added to fabrics, respectively, and the thermal activities of modified fabrics were studied. In addition, the thermal stability of PEG and fabric at a higher curing temperature was also discussed in detail. The results showed that the thermal properties of PEG decreased after being crosslinked to fabrics and the thermal activity parameters of treated fabrics could be changed and adjusted by selecting an appropriate two‐group mixing system. Some thermolysis and thermooxidative degradation of PEG and fabric used in the investigations might take place at higher curing temperatures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2288–2292, 2003
Novel positive‐working aqueous‐base developable photosensitive polyimide precursors based on diazonaphthoquinone‐capped polyamic esters
Authors: Hsu Steve Lien‐Chung , Lee Po‐I , King Jinn‐Shing , Jeng Jyh‐Long
Published: June 2004

Novel positive‐working aqueous‐base developable photosensitive polyimide (PSPI) precursors based on partially diazonaphthoquinone (DNQ)‐capped polyamic esters bearing phenolic hydroxyl groups and a DNQ photosensitive compound (PIC‐3) were developed. The partially DNQ capped polyamic esters were prepared from an esterification reaction of 1,2‐naphthoquinone diazide‐5‐sulfonyl chloride with the polyamic esters. The partially DNQ capped polyamic esters decreased the dark film loss effectively in the aqueous‐base developer and were able to make thicker film resists compared to the uncapped polyamic esters. The 25 mol % DNQ‐capped BisAPAF–PMDA polyamic ester and BisAPAF–ODPA polyamic ester containing 25 wt % PIC‐3 photosensitive compound showed a sensitivity of 176 and 185 mJ/cm2, and a contrast of 1.68 and 1.02, respectively, in a 3‐μm film with 1.25 wt % tetramethylammonium hydroxide developer. A pattern with a resolution of 5 μm was obtained from both PSPI precursor compositions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2293–2300, 2003
Subject categorization of query terms for exploring Web users' search interests
Authors: Pu Hsiao‐Tieh , Chuang Shui‐Lung , Yang Chyan
Published: June 2004

Subject content analysis of Web query terms is essential to understand Web searching interests. Such analysis includes exploring search topics and observing changes in their frequency distributions with time. To provide a basis for in‐depth analysis of users' search interests on a larger scale, this article presents a query categorization approach to automatically classifying Web query terms into broad subject categories. Because a query is short in length and simple in structure, its intended subject(s) of search is difficult to judge. Our approach, therefore, combines the search processes of real‐world search engines to obtain highly ranked Web documents based on each unknown query term. These documents are used to extract cooccurring terms and to create a feature set. An effective ranking function has also been developed to find the most appropriate categories. Three search engine logs in Taiwan were collected and tested. They contained over 5 million queries from different periods of time. The achieved performance is quite encouraging compared with that of human categorization. The experimental results demonstrate that the approach is efficient in dealing with large numbers of queries and adaptable to the dynamic Web environment. Through good integration of human and machine efforts, the frequency distributions of subject categories in response to changes in users' search interests can be systematically observed in real time. The approach has also shown potential for use in various information retrieval applications, and provides a basis for further Web searching studies.
Visualizing and tracking the growth of competing paradigms: Two case studies
Authors: Chen Chaomei , Cribbin Timothy , Macredie Robert , Morar Sonali
Published: June 2004

In this article we demonstrate the use of an integrative approach to visualizing and tracking the development of scientific paradigms. This approach is designed to reveal the long‐term process of competing scientific paradigms. We assume that a cluster of highly cited and cocited scientific publications in a cocitation network represents the core of a predominant scientific paradigm. The growth of a paradigm is depicted and animated through the rise of citation rates and the movement of its core cluster towards the center of the cocitation network. We study two cases of competing scientific paradigms in the real world: (1) the causes of mass extinctions, and (2) the connections between mad cow disease and a new variant of a brain disease in humans—vCJD. Various theoretical and practical issues concerning this approach are discussed.
Disciplinary differences and undergraduates' information‐seeking behavior
Authors: Whitmire Ethelene
Published: June 2004

This study applied the Biglan model of disciplinary differences to the information‐seeking behavior patterns of 5,175 undergraduates responding to questions on the College Student Experiences Questionnaire (CSEQ). The Biglan model categorizes academic disciplines along three dimensions: (1) hard‐soft, (2) pure‐applied, and (3) life–nonlife systems. Using t‐tests, this model proved to be valid for distinguishing differences in undergraduates' information‐seeking behavior patterns among various academic disciplines. The results indicate that the Biglan model has implications for the redesign of academic library services and use as a valid theoretical framework for future library and information science research.
Multitasking information seeking and searching processes
Authors: Spink Amanda , Ozmutlu H. Cenk , Ozmutlu Seda
Published: June 2004

Recent studies show that humans engage in multitasking behaviors as they seek and search information retrieval (IR) systems for information on more than one topic at the same time. For example, a Web search session by a single user may consist of searching on single topics or multitasking. Findings are presented from four separate studies of the prevalence of multitasking information seeking and searching by Web, IR system, and library users. Incidence of multitasking identified in the four different studies included: (1) users of the Excite Web search engine who completed a survey form, (2) Excite Web search engine users filtered from an Excite transaction log from 20 December 1999, (3) mediated on‐line databases searches, and (4) academic library users. Findings include: (1) multitasking information seeking and searching is a common human behavior, (2) users may conduct information seeking and searching on related or unrelated topics, (3) Web or IR multitasking search sessions are longer than single topic sessions, (4) mean number of topics per Web search ranged of 1 to more than 10 topics with a mean of 2.11 topic changes per search session, and (4) many Web search topic changes were from hobbies to shopping and vice versa. A more complex model of human seeking and searching levels that incorporates multitasking information behaviors is presented, and a theoretical framework for human information coordinating behavior (HICB) is proposed. Multitasking information seeking and searching is developing as major research area that draws together IR and information seeking studies toward a focus on IR within the context of human information behavior. Implications for models of information seeking and searching, IR/Web systems design, and further research are discussed.
Fusion of effective retrieval strategies in the same information retrieval system
Authors: Beitzel Steven M. , Jensen Eric C. , Chowdhury Abdur , Grossman David , Frieder Ophir , Goharian Nazli
Published: June 2004

Prior efforts have shown that under certain situations retrieval effectiveness may be improved via the use of data fusion techniques. Although these improvements have been observed from the fusion of result sets from several distinct information retrieval systems, it has often been thought that fusing different document retrieval strategies in a single information retrieval system will lead to similar improvements. In this study, we show that this is not the case. We hold constant systemic differences such as parsing, stemming, phrase processing, and relevance feedback, and fuse result sets generated from highly effective retrieval strategies in the same information retrieval system. From this, we show that data fusion of highly effective retrieval strategies alone shows little or no improvement in retrieval effectiveness. Furthermore, we present a detailed analysis of the performance of modern data fusion approaches, and demonstrate the reasons why they do not perform well when applied to this problem. Detailed results and analyses are included to support our conclusions.
Popul?r oder elit?r? Anmerkungen zum Kulturbegriff in der Geschichtswissenschaft
Authors: Witte Wilfried
Published: June 2004

While the Historische Kulturwissenschaft (new cultural history) is introduced as a new way of writing history the question has to be answered what Kultur (civilization) means or how it should be interpreted. The paper deals primarily with the special German notion of ‘Kultur’. The distinction between ‘intension’ and ‘extension’ is made and contrasted with both the narrow and the wide concept of ‘Kultur’. Writing history as new cultural history is shaped at least by five aspects: space, perspective, language, acting and time (particularly memory) which are discussed in this thesis. The intension of ‘Kultur’ in Historische Kulturwissenschaft leads to popularisation. The sense of the popular approach to history emphasizes modality in the conception and writing of history.
Vom Wesen der langz?ngigen Schl?rfm?use: Das Schnabeltier und die Entwicklung der Informationsgesellschaft
Authors: Herren Madeleine
Published: June 2004

In 1798, the skin of a platypus started to disturb the European scientific community. Even before researchers confirmed that the furry animal with a duck's bill was an egg‐laying mammal, the platypus was a challenge to contemporary taxonomies. Although a scientific interest in the platypus is self‐evident, the animal's appearance in encyclopaedias and dictionaries needs an explanation. The essay discusses the presence of the platypus in the encyclopaedias of the 19th and 20th century by asking why a rare animal without economic significance came into an encyclopaedia where knowledge had to be reduced to information of general interest. Therefore, the transformation of the platypus in a part of general knowledge describes the presence of order even outside the philosophical discourse described by Foucault. As a visual expression of order, the platypus gives an example how knowledge and society are connected, and how a social and cultural context influenced the supposed objective description of an animal.
Menschenbild und Wirtschaftsordnung: Der Menschenbegriff im Kameralismus und in der National?konomie
Authors: Bowler Richard C.
Published: June 2004

This essay addresses the construction of human nature in cameralism and early German political economy. It suggests that the emergent economic sciences in Germany propounded a vision of human beings that stressed the psycho‐physiological roots of human behavior in general, and of economic activity in particular. In this vision, human beings possessed a body and soul whose constant interaction gave rise to needs and desires, and thus to the drive to behave as economic agents. Here the cameralists and early German political economists adopted conceptions of human nature current in the ‘Sciences of Man’ of the Enlightenment. This stress on the non‐rational, psycho‐physiological aspects of human nature prevented the theoretical construction of a stable human social life, and in this way justified the continued need for governmental oversight and control of economic activity.
Imagination — Einbildungskraft — Suggestion: Zur ‚Scharlatanerie’︁ in der neuzeitlichen Medizin
Authors: Schott Heinz
Published: June 2004

In Renaissance and early modern times, the concept of imagination (Latin imaginatio) was essential for the (natural) philosophical explanation of magic processes, especially in the anthropology of Paracelsus. He assumed that imaginatio was a natural vital power including cosmic, mental, psychical, and physical dimensions. The Paracelsians criticized traditional humor pathology ignoring their theory of ‚natural magic’︁. On the other hand, they were criticized by their adversaries as charlatans practicing ‚black magic’︁. About 1800, in between enlightenment and romanticism, the healing concept of ‚animal magnetism’︁ (Mesmerism) evoked an analogous debate, whether ‚magnetic’︁ phenomena originated from a real (physical) power (so‐called ‚fluidum’︁) or were just due to fantasy or imagination (German Einbildungskraft). At the end of the 19th century, the French internist Hippolyte Bernheim created — against the background of medical hypnosis (‚hypnotism’︁) as a consequence of Mesmerism — his theory of suggestion and autosuggestion: a new paradigm of psychological respectively psychosomatic medicine, which became the basis for the concept of ‚placebo’︁ in modern biomedicine. From now on, all the effects of ‚alternative medicine’︁ could easily be explained by the ‚placebo‐effect’︁, more or less founded — at least unconsciously — on fraud.
Paracelsus in pseudoparacelsischen Briefen
Authors: Telle Joachim
Published: June 2004

The article presents an investigation of pseudo‐Paracelsian letters, forgeries written by unidentified sixteenth‐century Paracelsists. It comprises information about extant texts as well as authors and addressees like Bartholomaeus Korndorfer, Salomon Trismosin and Wilhelm von Hohenheim. The separation of fact and fiction reveals Paracelsus' life and work to be misrepresented or even distorted in these letters. Paracelsus appears as a theological ‘fanaticus’, moreover as a stylised hero of the alchemia transmutatoria metallorum. A multifaceted opposition and reform movement, ‘Paracelsianism’, revolved around Paracelsus as an idolised, almost apotheosised leader and inspirational figure. Its followers are known to demand a revision of some areas of knowledge in the Aristotelian‐Galenic medical and pharmaceutical traditions; they furthermore fermented the aspirations of certain anti‐confessionalistic religious dissidents. The pseudo‐Paracelsian letters, which has hitherto been generally neglected, reinforces this.
Aufklärung durch Täuschung, Die Natürliche Magie im 18.?Jahrhundert
Authors: Hochadel Oliver
Published: June 2004

Mechanical speaking figures are very popular in the 18th century. Purportedly they are not only able to answer questions but also to divine. The enlightened philosophers are alarmed in the face of apparent fraud fostering superstition. The most successful weapon against the ‘charlatans’ seems to be the public imitation of their tricks. This leads to a ‘division of labour’ between popularisers of science, instrument‐makers and even some showmen, and natural philosophers. The former expose the imposture thanks to their special skills, the latter support these fraudbusting activities with their growing cultural authority. This paves the way for a close alliance between professional magicians and scientists in the 19th and 20th century exposing spiritistic mediums and spiritual healers.
‚Charlataneria Eruditorum’︁, Zur sozialen Semantik des gelehrten Betrugs im 17. und 18. Jahrhundert
Authors: Füssel Marian
Published: June 2004

In the 17th and 18th century republic of letters the problem of scientific fraud was met with a discourse of charlatanism. Departing from Johann Burckhard Menckes famous treatise on the Charlatanry of the learned the following essay traces how the accusations of academic and scientific misconduct put in terms of ‚charlatanry’︁ primarily helped to produce the new species of the erudite ‚charlatan’︁. Facing a growing complexity of scientific culture this new frame of meaning, structured by numerous examples of scientific misconduct offered a new way of orientation in the world of learning. But besides its cognitive impacts the discourse of charlatanry allowed to create symbolic boundaries, which determined decisions upon the affiliation or non affiliation to the new forming scientific community by separating honourable from dishonourable scientific personae. Speaking of charlatanry therefore always implied a social distinction as much as a scientific. The discourses on charlatanry also mirror differentiations within the scientific field. At first dominated by a critique built on courteous or bourgeois values, the scientific field later on developed its own criteria of appraisal like authorship, originality, transparency etc. Attracting the attention of a further growing public sphere, the explicit verbalisation of claims not relating to the value system of a republic of letters primarily concerned with the production and distribution of knowledge finally led up to a more implicit moral economy of science. A change that at a large scale level can be described both as an internalisation of the values of scientific conduct and a differentiation between justiciable and unjusticiable transgressions of the norms set up by the scientific community.
A Nonparametric Test for Random Dropouts
Authors: Listing Joachim , Schlittgen Rainer
Published: June 2004

The problem of dropout is a common one in longitudinal studies. One usually assumes for the analysis that dropout is at random. There are some tests to investigate this assumption. But these tests depend on normally distributed data or lack power, cf.ListingandSchlittgen(1998). We here propose an overall test which combines several Wilcoxon rank sum tests. The alternative hypothesis states that there is a tendency for larger (smaller) values of the target variable the last time the probands show up.

The test is applicable with many ties also. It proves to perform well, compared to the test developed for normally distributed data, as well as to a test for completely missing at random which is proposed byLittle(1988). An application to real data is given too.
Statistical Inference For Risk Difference in an Incomplete Correlated 2 × 2 Table
Authors: Tang Nian‐Sheng , Tang Man‐Lai
Published: June 2004

In some infectious disease studies and 2‐step treatment studies, 2 × 2 table with structural zero could arise in situations where it is theoretically impossible for a particular cell to contain observations or structural void is introduced by design. In this article, we propose a score test of hypotheses pertaining to the marginal and conditional probabilities in a 2 × 2 table with structural zero via the risk/rate difference measure. Score test‐based confidence interval will also be outlined. We evaluate the performance of the score test and the existing likelihood ratio test. Our empirical results evince the similar and satisfactory performance of the two tests (with appropriate adjustments) in terms of coverage probability and expected interval width. Both tests consistently perform well from small‐ to moderate‐sample designs. The score test however has the advantage that it is only undefined in one scenario while the likelihood ratio test can be undefined in many scenarios. We illustrate our method by a real example from a two‐step tuberculosis skin test study.
Estimation of the Parameters of two Parallel Regression Lines Under Uncertain Prior Information
Authors: Khan Shahjahan
Published: June 2004

The problem of parallelism for bi‐linear regression lines arises in many real life investigations. For two linear regression models with normal errors, the estimation of the slope as well as the intercept parameters is considered when it is apriori suspected that the two lines are parallel. Three different estimators are defined by using both the sample data and the non‐sample uncertain prior information. The relative performances of the unrestricted, restricted and preliminary test estimators are investigated based on the analysis of the bias, and risk functions under quadratic loss. An example based on a medical study is used to illustrate the method.
Midlevel Management in the Community College: A Rose Garden?
Authors: Gillett‐Karam Rosemary
Published: June 2004

Recognizing that the duties and responsibilities of the department chair in the community college are quite complex, North Carolina State University developed a training program for practitioners.
Meeting the Millenium's Challenge: Leading from Where You Are
Authors: Spaid Robin L. , Parsons Michael H.
Published: June 2004

A new paradigm for leadership in the twenty‐first century identifies essential elements for adapting to change: weaving a shared vision, appreciating a variety of views, communicating effectively, making decisions based on principles, and creating the future.
A Statewide Survey of New Department Chairs: Their Experiences and Needs in Learning Their Roles
Authors: Smith Albert B. , Stewart Gloria A.
Published: June 2004

Workplace socialization theory is a useful framework for understanding the experiences of new department chairs and for meeting their professional development needs.
College Presidents Examine Midlevel Management in the Community College
Authors: Gillet‐Karam Rosemary , Cameron Donald W. , Messina Robert C. , Mittelstet Stephen K. , Mulder Anne E. , Sykes Abel B. , Thornton Jerry Sue
Published: June 2004

In conversations with six community college presidents, issue editor Rosemary Gillet‐Karam asks about the definitions, roles, essential skills, and accomplishments of midlevel managers at their respective institutions.
The Urban Postbaccalaureate Reverse Transfer Student: Giving New Meaning to the Term Second Chance
Authors: Quinley John W. , Quinley Melissa P.
Published: June 2004

This chapter analyzes the life circumstances and goals of postbaccalaureate reverse transfer students in an urban North Carolina community college.
Urban America and the Community College Imperative: The Importance of Open Access and Opportunity
Authors: Smith Joshua L. , Vellani Fayyaz A.
Published: June 2004

Urban community colleges have unique missions geared to providing access and fostering community for the diverse student populations—majority minorities—living today in American cities.
The Los Angeles Community Colleges: Pathways to Urban Change
Authors: Fujimoto Jack
Published: June 2004

This case study of the Los Angeles Community Colleges presents the challenges of a district that is trying to cope with changing social and economic needs.
Sources and Information About Urban Community Colleges
Authors: Peterman Dana Scott , Kozeracki Carol A.
Published: June 2004

This annotated bibliography directs readers to additional publications that address topics pertinent to urban community colleges.
Interdisciplinary Studies in the Community Colleges
Authors: Walker Arianne Abell
Published: June 2004

After reviewing definitions of interdisciplinary courses and summarizing different existing programs, the author analyzes the interdisciplinary course offerings of colleges in the Center for the Study of Community Colleges' 1998 Curriculum Project. Comparisons are made with data from the 1991 curriculum study.
English as a Second Language in the Community College Curriculum
Authors: Kuo Elaine W.
Published: June 2004

This chapter discusses the impact of immigration on English as a Second Language (ESL) programming. Subsequently, the author presents the status of ESL course offerings in community colleges as reflected in the Center for the Study of Community Colleges' Curriculum Project, reviews existing ESL curriculum course designs, and summarizes the implications for community colleges.
Scratching the Surface: Distance Education in the Community Colleges
Authors: Kozeracki Carol A.
Published: June 2004

This article reviews the current status of distance education in general and at the community college level in particular. It then describes the distance‐education‐related findings from the Center for the Study of Community Colleges' 1998 Curriculum Project.
Sources and Information: Forces Influencing the Curriculum
Authors: Keup Jennifer Rinella
Published: June 2004

This annotated bibliography lists ERIC documents covering the factors that influence the development of the community college curriculum, including state policy, initiatives or grants from private organizations and foundations, new technologies, and the broadening understanding of the dynamics of teaching and learning.
Toward a Definition of Deaning
Authors: Robillard, Jr. Douglas
Published: June 2004

This chapter discusses the multitude of tasks that community college academic deans perform and the evolution of the role of dean through the present. It also examines current job descriptions and discusses some of the skills that are essential to the dean's survival.
The Dean as Chief Academic Officer
Authors: Erwin John Stuart
Published: June 2004

This chapter examines the role of the dean as chief academic officer with primary responsibility for curriculum development and the instructional integrity of the college.
The Dean and the Faculty
Authors: Andrews Hans A.
Published: June 2004

The academic dean carries a major responsibility for the teaching and learning outcomes of a community college. Assisting faculty to obtain a high level of teaching competence is paramount to the role.
The Dean and the President
Authors: Kuss Hans J.
Published: June 2004

When the college president and dean develop a close working relationship, they act synergistically for the good of the institution.
Working with Media Outlets to Communicate with the Public
Authors: Wallace Mark L.
Published: June 2004

How can community colleges use the tools of the trade within the media to their best advantage? This chapter provides examples of the best practices and offers practical suggestions for using resources available to everyone.
The Media as Teacher: Helping Advisers, Mentoring Young Journalists
Authors: Tatum Christine
Published: June 2004

Thanks to the Internet, more outside experts can be invited into the community college classroom than ever before. This chapter reviews innovative ways in which community colleges can train future journalists and new media professionals.
Sources and Information: Media Relations in Community Colleges
Authors: Tobolowsky Barbara
Published: June 2004

This annotated bibliography presents recent ERIC documents that provide insight into the public perception of community colleges, the potential influence of the media on public opinion regarding community colleges, institutional relations with the media, and the role that Web pages play in strategic marketing.
A K–12 Perspective on Partnerships with Community Colleges
Authors: Azinger Al
Published: June 2004

It is not always apparent to the K–12 administrators that collaboration with community colleges will help address the issues that demand the priority attention of school leaders.
Establishing and Sustaining a Middle College High School
Authors: Cunningham Cecilia L. , Wagonlander Chery S.
Published: June 2004

Since 1973, middle college high schools, sponsored by local community colleges, have worked with local school districts as well as parents to create unique learning enviroments for at‐risk youth. This chapter provides a model for the planning and operation of a new institution based on Middle College at LaGuardina Community College (New York) and Mott Middle College at Mott Community College (Michigan).
Working with Urban Schools That Serve Predominantly Minority Students
Authors: Chen May Kuang‐chi , Konantz James L. , Rosenfeld M. Lucia , Frost Clara
Published: June 2004

Los Angeles Trade Technical College and the Los Angeles Unified School District have collaborated in several ways to help the ethnically diverse, urban school children prepare for and make the transition to college.
Demographics, State Education Reform Policies, and the Enduring Community College Role as an Extension of the Schools
Authors: Palmer James C.
Published: June 2004

The significant number of recent high school graduates who move on to the community college, as well as state education reform policies that link student achievement in school to subsequent success in college, require community colleges to monitor student flow from the high schools and articulate curricula with the courses offered in local school districts.
Sources and Information
Authors: Outcalt Charles L.
Published: June 2004

This chapter presents an annotated bibliography of recent ERIC documents that describe the benefits and pitfalls of collaborations between community colleges and high schools.
Motivating and Maximizing Learning in Minority Classrooms
Authors: Sanchez Irene M.
Published: June 2004

Successful learning experiences contribute to student motivation and retention and require that educators design programs around learning preferences. This chapter discusses the relationship of learning preferences to motication and retention and presents a profile of learning preferences of Hispanic and Native American learners.
Increasing Retention and Success Through Mentoring
Authors: Stromei Linda K.
Published: June 2004

Increasing retention and success for minority students through mentoring is the focus of this chapter. A model for a formal mentoring program AMIGOS(tm), is discussed with details for implementation.
Using Technology to Facilitate Learning for Minority Students
Authors: Palma‐Rivas Nilda
Published: June 2004

The use of educational technology not only facilitates learning but also provides educational access to students at a distance. This chapter outlines issues instructors should consider when integrating technology into the curriculum.
Integrating Nonminority Instructors into the Minority Environment
Authors: Townsend Barbara K.
Published: June 2004

For white faculty members to be effective in a minority institution, they must be aware of how their racial identity affects their perceptions, content knowledge, and classroom values, and they must be willing to share these insights with their students.
Electron Delocalization and Electrostatic Repulsion at the Origin of the Strong Spin Coupling in Mixed‐Valence Keggin Polyoxometalates: Ab Initio Calculations of the One‐ and Two‐Electron Processes
Authors: Suaud Nicolas , Gaita‐Ariño Alejandro , Clemente‐Juan Juan Modesto , Coronado Eugenio
Published: June 2004

We present here a general theoretical procedure to treat the problem of electron delocalization and magnetic interactions in high‐nuclearity mixed valence clusters based on polyoxometalates. The main interactions between the delocalized electrons of mixed‐valence polyoxometalate anions are extracted from valence spectroscopy ab initio calculations on embedded fragments. Electron transfer, magnetic coupling and exchange transfer parameters between nearest and next‐nearest‐neighbor metal ions, as well as the value of the electrostatic repulsion between pairs of metal ions are determined. These parameters are introduced in a model Hamiltonian that considers the whole anion. It thus provides macroscopic properties that should be compared with the experimental data. This method is applied to a two‐electron‐reduced polyoxowolframate Keggin anion. The results demonstrate that the electron transfer processes, combined with the Coulombic repulsion between the “extra” electrons, induce a strong antiferromagnetic coupling between the two delocalized spins providing a definite explanation of the diamagnetic properties of these high nuclearity mixed‐valence clusters.
Entwicklung eines neuartigen Staustrahl‐Membranreaktors für die Zellkulturtechnik mittels CFD
Authors: Bohlmann J.T.
Published: June 2004

No abstracts.
Enzymatisch katalysierte Synthese von Galactosyl‐Oligosacchariden in einem kontinuierlichen Membranreaktorsystem
Authors: Czermak P. , Ebrahimi M. , Grau K. , Netz S. , Sawatzki G.
Published: June 2004

No abstracts.
Endurance Limit of Ground and TIG Dressed Steel Welded Joints under Proportional Loading
Authors: Rudolph J.
Published: June 2004

Post weld treatment methods such as disk and burr grinding or TIG dressing improve the fatigue performance of steel welded joints. As the crack like defects at the weld toes are removed, a significant increase in fatigue strength and particularly in the endurance limit is achieved. This improvement in the fatigue behaviour is currently considered by bonus factors based on general experimental observations. No code‐based design approach for the assessment of the endurance limit of these components is available currently. As the fatigue behavior of these types of welded joints is similar to that of non‐welded and notched components established design methodologies, such as the local strain approach, are appropriate tools for these purposes. Furthermore, this design approach is open to extension to the finite life region and even the low cycle fatigue regime.
Messungen von Sorptionsisothermen und Diffusionskoeffizienten in Polymerlösungen
Authors: Schabel W. , Mamaliga I. , Kind M.
Published: June 2004

No abstracts.
Koppelung von CFD und Prozesssimulation zur industriellen Auslegung von Spaltöfen für Olefinanlagen
Authors: Möbus H. , Kaufmann D.
Published: June 2004

No abstracts.
Simulation kompressibler pulsierender Strömungen in Verdichter‐Rohrleitungssystemen mit dem Simulationssystem PURO2002
Authors: Stehr H.
Published: June 2004

No abstracts.
Tropfenpopulationsmodellierung – Einfluss von Stoffsystem und technischen Geometrien
Authors: Schmidt S.A. , Simon M. , Bart H.‐J.
Published: June 2004

No abstracts.
Kompaktes Faltreaktorkonzept zur autothermen Dampfreformierung mit integrierter Verdampfung und Shift‐Stufe
Authors: Morillo A. , Merten C. , Eigenberger G. , Hermann I. , Lemken D.
Published: June 2004

No abstracts.
pH‐Glassensoren in fotostrukturierten Fluidikbausteinen
Authors: Kaden H. , Herrmann S.
Published: June 2004

No abstracts.