bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surfactant‐Directed Polypyrrole/CNT Nanocables: Synthesis, Characterization, and Enhanced Electrical Properties
Authors: Zhang Xuetong , Zhang Jin , Wang Rongming , Zhu Tao , Liu Zhongfan 
Published: July 2004

AbstractWe describe here a new approach to the synthesis of size‐controllable polypyrrole/carbon nanotube (CNT) nanocables by in situ chemical oxidative polymerization directed by the cationic surfactant cetyltrimethylammonium bromide (CTAB) or the nonionic surfactant polyethylene glycol mono‐p‐nonylphenyl ether (Oπ–10). When carbon nanotubes are dispersed in a solution containing a certain concentration of CTAB or Oπ–10, the surfactant molecules are adsorbed and arranged regularly on the CNT surfaces. On addition of pyrrole, some of the monomer is adsorbed at the surface of CNTs and/or wedged between the arranged CTAB or Oπ–10 molecules. When ammonium persulfate (APS) is added, pyrrole is polymerized in situ at the surfaces of the CNTs (core layer) and ultimately forms the outer shell of the nanocables. Such polypyrrole/CNT nanocables show enhanced electrical properties; a negative temperature coefficient of resistance at 77–300 K and a negative magnetoresistance at 10–200 K were observed.
Photochromism of Novel Molybdate/Alkylamine Composite Thin Films
Authors: Chen Zhaohui , Loo Boon H. , Ma Ying , Cao Yunwei , Ibrahim Amin , Yao Jiannian 
Published: July 2004

AbstractNovel inorganic/organic composite films of molybdates with photochromic properties have been prepared by self‐assembly using alkylammonium ions as a supramolecular template. Both 1‐hexadecylammonium/polyoxomolybdate (C16‐Mo) and 1‐octadecylammonium/polyoxomolybdate (C18‐Mo) composite films have been successfully fabricated. The elemental analysis and thermal gravimetric analysis show that the main product in the C16‐Mo film was (C16H33NH3)4Mo8O26. The X‐ray diffraction (XRD) results indicate that the composite films were lamellar in nature. The IR, Raman and X‐ray photoelectron spectroscopy (XPS) results show that the polyoxomolybdate anions present as MoO6 octahedra and that the Mo species exists as Mo6+ in the freshly prepared films. The alkyl chains in the 1‐hexadecylammonium chains were linear and the alkyl groups are an all‐trans configuration. Upon UV irradiation of the C16‐Mo films, some Mo6+ was reduced to Mo5+, some ‐NH3+ became ‐NH2 with a concomitant increase in the concentration of ‐OH groups on the molybdate moieties, and the films were colored. Thus, the photochromism of the films involves the reduction of Mo6+ to Mo5+, coupled with a proton transfer from 1‐hexadecylammonium ions to an oxygen atom at the Mo site. In contrast to thin films of transition‐metal oxides, which all show photochromism in the blue region of the electromagnetic spectrum, these composite films show photochromism in the violet region with the greatest absorbance change at 472 nm.
On Superconductivity and Superfluidity (What I Have and Have Not Managed to Do), as well as on the ‘Physical Minimum’ at the Beginning of the 21st Century
Authors: Ginzburg Vitaly L. 
Published: July 2004

AbstractThe question of thermeolectric effects in superconductors is still a particular problem, which evidently emerges only in the presence of a temperature gradient. The well‐known Londons theory yielded much, and is widley employed under certain conditions even nowadays, but is absolutely insufficient and has to be generalized. This problem was solved in the Ψ‐theory of superconductivity by V. L. Ginzburg and L. D. Landau. Together they developed a phenomenological theory of superconductivity in the late 1940s. This theory proposes that those electrons that contribute to superconduction form a superfluid. The superconductor is described by a complex function Ψ called the order parameter, and |Ψ|2 indicates the fraction of electrons that has condensed into a superfluid.In his Nobel lecture V. L. Ginzburg also gives a ‘list’ of top problems in contemporary physics. Acquaintance with all subjects included in this ‘list’ is what he calls the ‘physical minimum’.
Mechanism of Reduction of the Nitrite Ion by CuI Complexes
Authors: Burg Ariela , Lozinsky Evgenia , Cohen Haim , Meyerstein Dan 
Published: July 2004

AbstractThe reaction of Cu+aq with NO2− was studied. The results are consistent with the mechanism: Cu+aq + NO2− →← (Cu+NO2−), K = 140 ± 30 M−1; (Cu+NO2−) + H+ → Cu2+ + NO + OH−, k = 4.6 × 105 M−1s−1. It is proposed that the copper is bound to the nitrogen in the transient complex (Cu+NO2−). In addition, the reaction was studied with (CuILi)+ complexes. The results show that the ligands reduce the value of K and that their effect on k depends on the redox potential of the (CuII/ILi) couple. This reaction is the simplest model for the CuNIR (NIR = Nitric reductase) enzymes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Divergent evolution in fluviokarst landscapes of central Kentucky
Authors: Phillips Jonathan D. , Martin Linda L. , Nordberg Viva G. , Andrews William A. 
Published: July 2004

AbstractCentral Kentucky is characterized by a mixture of karst and ﬂuvial features, typically manifested as mosaic of karst‐rich/channel‐poor (KRCP) and channel‐rich/karst‐poor (CRKP) environments. At the regional scale the location and distribution of KRCP and CRKP areas are not always systematically related to structural, lithological, topographic, or other controls. This study examines the relationship of KRCP and CRKP zones along the Kentucky River gorge area, where rapid incision in the last 1·5 million years has lowered local base levels and modiﬁed slopes on the edge of the inner bluegrass plateau. At the scale of detailed ﬁeld mapping on foot within a 4 km2 area, the development of karst and ﬂuvial features is controlled by highly localized structural and topographic constraints, and can be related to slope changes associated with retreat of the Kentucky River gorge escarpment. A conceptual model of karst/ﬂuvial transitions is presented, which suggests that minor, localized variations are sufﬁcient to trigger a karst–ﬂuvial or ﬂuvial–karst switch when critical slope thresholds are crossed. Copyright © 2004 John Wiley & Sons, Ltd.
Tailings fans and valley‐spur cutoffs created by hydraulic mining
Authors: James L. Allan 
Published: July 2004

AbstractSand and gravel tailings from nineteenth century open‐pit hydraulic gold mines formed large alluvial fans at tributary conﬂuences in the northwestern Sierra Nevada, California. In the Bear River watershed, several of these fans were so large that they blocked main channels for decades. Some channels not only aggraded deeply, but also moved laterally and cut across the inner bends of valley spurs. Now locked in bedrock channels, these valley‐spur cutoffs impose local controls on geomorphic, hydraulic, and sedimentary processes. One cutoff has incised 25 m into bedrock over the past century (25 cm a−1) with rapid initial incision rates of up to 50 cm a−1 (1884–1890). Recognition of spur cutoffs in the geological record may help to identify large landslides and provide an analogue for a type of natural earthﬁll dam spillway not prone to catastrophic failures. Tailing fans, valley‐spur cutoffs, and the sediment they trap are described from contemporary accounts and recent ﬁeld conditions in the Bear River watershed. These anthropogenic changes represent a major shift in the watershed from supply‐limited to transport‐limited sediment budgets and a change in geomorphic processes away from long‐term drainage evolution dominated by ingrown meanders. The large volumes of mining sediment stored in these landforms will be slowly released over the next millennium and could be signiﬁcant to contemporary ecological and public health issues due to recent ﬁndings of high mercury loadings associated with hydraulic mines. Copyright © 2004 John Wiley & Sons, Ltd.
Analysis of crack movements observed in an alpine bedrock cliff
Authors: Ishikawa Mamoru , Kurashige Yoshimasa , Hirakawa Kazuomi 
Published: July 2004

AbstractCrack widths and rock temperatures were monitored on an andestic bedrock cliff in the summit area of the Daisetsu Mountains, Hokkaido, northern Japan. Sequential data recorded the gradual widening of a crack to the point of critical crack extension, which resulted in catastrophic rock breakage. The data indicate that a combination of liquid water inﬁltration into crack tip and subsequent freezing is the most signiﬁcant factor contributing to critical crack extension. The recorded sub‐critical crack movements involved a number of minor crack extensions and contractions, the timing of which correlates well with the magnitude of the reconstructed thermal stresses at the crack tip derived from thermal deformation of the plate‐shaped rock fragment. Larger crack extensions occurred when stress at the crack tip exceeded a threshold value, possibly reﬂecting the control of rock fracture mechanics by which cracks are thought to propagate when the stress intensity factor at the crack tip exceeds the threshold values for stress corrosion cracking and the fracture toughness of the material. Copyright © 2004 John Wiley & Sons, Ltd.
Application of lidar digital terrain modelling to predict intertidal habitat development at a managed retreat site: Abbotts Hall, Essex, UK
Authors: Blott Simon J. , Pye Kenneth 
Published: July 2004

AbstractA key question in designing any managed retreat site concerns the nature of the habitats which will be created, and their likely long‐term sustainability and development. Studies of historical sea wall failures in Essex have shown that former reclaimed areas may respond to renewed tidal ﬂooding in different ways depending on a number of factors, most importantly the elevation of the land at the time of breach, which governs the frequency and duration of tidal ﬂooding. This paper demonstrates how digital terrain modelling using airborne lidar data can be used to calculate the elevation of the land behind a breach and to predict the likely habitats which will be created. When combined with data from sites of historical sea wall failure, predictions can also be made about the likely geomorphological and biological evolution of the created habitats in the longer term. At Abbotts Hall on the northern side of Salcott Creek, Essex, where a managed retreat scheme was activated in October 2002, the highest areas above 2·35 m OD were predicted to develop stable saltmarsh, intermediate areas between 2·1 and 2·34 m OD to develop potentially unstable saltmarsh which is likely undergo internal dissection, and the lowest areas below 2·1 m OD to remain as mudﬂat or lagoon. Approximately 38 per cent of the site was predicted to develop stable saltmarsh, and nearly 50 per cent to remain as lagoon or mudﬂat. Monitoring is now being undertaken but it will be several years before the accuracy of the predictions can be assessed. Copyright © 2004 John Wiley & Sons, Ltd.
Hypsometry of glaciated landscapes
Authors: Brocklehurst Simon H. , Whipple Kelin X. 
Published: July 2004

AbstractHypsometry (frequency distribution of elevations) is often used to characterize landscape morphology, traditionally in the context of the degree of ﬂuvial dissection. Recently, the hypsometry of glaciated regions has been used to infer how rates of glacial erosion compare with tectonic uplift rates. However, many factors other than tectonics can also exert a major inﬂuence on the hypsometry of a glaciated landscape, resulting in a wide variety of hypsometries. Using examples from the eastern Sierra Nevada, California, the western Sangre de Cristo Range, Colorado, and the Ben Ohau Range, New Zealand, we demonstrate that, all else being equal, the hypsometries of neighbouring basins can indicate the relative degree of glacial modiﬁcation in each. A selection of drainage basins from the Rocky Mountains shows that the position of the equilibrium line altitude (ELA) within the drainage basin relief is a dominant variable in determining the hypsometry of a glaciated basin. This is a non‐linear effect: once the ELA falls to some critical level, the glaciers scour deeply below the ELA, causing a noticeably different hypsometry. The hypsometry of an arbitrary region encompassing many drainage basins can disguise the variation present in the hypsometries, and thus landforms, of the individual basins. Unique local circumstances, such as the presence of a mountain iceﬁeld (Waiho Basin, Southern Alps), substantial hanging valleys (Avalanche Creek, Glacier National Park), a narrow outlet canyon (Sawmill Creek, Sierra Nevada), and isolated geologic structures (Baker Creek, Sierra Nevada), can have a major impact on the hypsometry of an individual basin. Copyright © 2004 John Wiley & Sons, Ltd.
Pollution prevention success stories at the Oklahoma City Air Logistics Center
Authors: Hall Freddie E. 
Published: July 2004

AbstractThe goal of the Oklahoma City Air Logistics Center's (OC‐ALC) Pollution Prevention Program is simple, direct, and fundamental: reduce the purchase and use of targeted toxic chemicals. The OC‐ALC has become the Air Force leader in introducing new prototype technologies into all maintenance processes and quantifying their environmental benefits. The innovative technologies are reducing the handling of hazardous materials and eliminating hazardous waste. The success of the program lies in coordinating efforts, promoting awareness, transferring technology, obtaining funds, and executing projects. The OC‐ALC Pollution Prevention Program involves efforts to reduce the use of toxic chemicals through a hierarchy of actions: source reduction, chemical substitution, recycle and reuse, treatment, and disposal. Pollution prevention first seeks to change processes to eliminate the purchase and generation of undesirable targeted materials (source reduction). Where source reduction is not feasible, environmentally compliant materials may be substituted for the noncompliant products. The next P2 action is to recycle and reuse the hazardous materials. The following P2 actions include the treatment and disposal of wastes and emissions control (abatement) to reduce environmental impacts prior to disposal and only when source reduction and chemical substitution actions are not feasible (cost‐prohibitive, immature technology, etc.). At the root of the program is a compliance site assessment that identified four major processes in aircraft depot maintenance activities (painting, depainting, cleaning, and electroplating) that generate the majority of the installation's hazardous waste. Purchase and use of hazardous chemicals are tracked to verify the validity of implemented technologies and monitor trends. The objective of this article is to highlight technologies that have reduced targeted hazardous chemical purchases by 1.5 million pounds, reduced the generation of hazardous industrial waste by 8 million pounds, and reduced the use of ozone‐depleting substances (ODSs) by 330,000 pounds, annually. This article will highlight the following technologies: abrasive carbon dioxide blasting, environmentally acceptable chemical depainting agents, radome chemical depainting, medium‐pressure water jet knife, high‐pressure aircraft component subsystem, advanced vapor degreaser, National Emissions Standards for Hazardous Air Pollutants (NESHAP)‐compliant wipe solvents, powder coatings, and alternative electroplating technologies (i.e., ion vapor deposition, high‐velocity oxygen fuel, electromagnetic particle deposition, etc.). © 2004 Wiley Periodicals, Inc.
Toxic mold assessment, mitigation, and prevention at DOD facilities
Authors: Taylor Kim , Clifford Regina , Kollmeyer Ben , Pielak Janine 
Published: July 2004

AbstractThe objective of this article is to discuss emerging toxic mold issues facing Department of Defense (DOD) facilities. Mold exposure has been blamed as the cause of serious human health problems, and several mold species commonly found indoors have recently been identified as potential human health hazards. This article discusses common types and causes of indoor mold; exposure routes for mold; potential health impacts attributed to mold; disclosure obligations during property transactions; recent mold litigation; emerging regulations; and the application of a mold assessment, mitigation, and prevention program (AMPP) to DOD facilities undergoing closure under the Base Realignment and Closure (BRAC) Act, to active DOD facilities, and to new DOD construction projects. © 2004 Wiley Periodicals, Inc.
Planning for the Future Force: The sustainable Fort Bragg story
Authors: Davis Addison D. , Hull Christine G. 
Published: July 2004

Abstract“We need to consider managing [the environment] to operational requirements, not just regulatory requirements.” This observation from Air Force Deputy Assistant Secretary Maureen Koetz in the autumn 2003 issue of FFEJ highlights the fundamental challenge facing military environmental programs as they attempt to support transforming missions. It has been said that “change is the Army's steady state; the Army is always in transition.” To ensure that U.S. military forces can continue to perform their current and future missions without being constrained by environmental issues, the current “stovepiped” installation planning processes for infrastructure, budget, military training and deployment, and environment must become interdependent and integrated. Integrated planning is inherently tied to the concept of living within the limits of available resources, both natural and manmade. This article highlights a developing approach to resource and planning processes at Army installations. The Army Installation Sustainability Program focuses long‐term resource planning and execution on an installation's ability to support the Future Force and coexist with the communities that grow on its borders. The authors discuss the overall process and specific accomplishments of Fort Bragg's sustainability program and demonstrate how this paradigm shift toward a sustainability management system is successfully helping the installation staff prepare for the future. © 2004 Wiley Periodicals, Inc.
Integrating NEPA, environmental permitting, and contracting actions into a DOD hazardous waste treatment facility construction project to successfully meet budget and schedule
Authors: Pringle William J. B. 
Published: July 2004

AbstractEnvironmental managers responsible for high‐profile Department of Defense (DOD) construction projects entailing National Environmental Policy Act (NEPA) and environmental permitting requirements must constantly monitor cost and schedule. For numerous interrelated reasons, NEPA and environmental permitting are the initial critical path activities and are constantly scrutinized by higher management levels, as they have the potential to significantly affect life‐cycle budgets and schedule if mismanaged. Maintaining effective management vigilance is therefore required to ensure environmental actions remain on schedule and support projected contract award dates and submitted budgets. This article provides some insights into how to integrate NEPA, permitting, contracting, and budgeting to achieve and maintain success from project inception to conclusion. © 2004 Wiley Periodicals, Inc.
Different roles of the frontal and parietal regions in memory‐guided saccade: A PCA approach on time course of BOLD signal changes
Authors: Sugiura Motoaki , Watanabe Jobu , Maeda Yasuhiro , Matsue Yoshihiko , Fukuda Hiroshi , Kawashima Ryuta 
Published: July 2004

AbstractAlthough involvement of the frontoparietal regions in visually guided saccade and visuospatial attention has been established, functional difference of the frontal and parietal regions suggested in neuropsychological observations and lesion studies in animals has not been explicitly supported by functional imaging studies. Considering a possible disadvantage of cognitive subtraction in an interregional comparison, we directly compared the time course of BOLD signal changes across regions. Normal subjects performed a modified version of a memory‐guided saccade task in which saccade was performed both during encoding and execution phases. In addition, the delay period was fixed and the peripheral target was presented also during the execution phase together with distracters. Therefore, visuospatial representation was likely maintained in the sensory domain during the delay phase. A principal component analysis on the time‐course data separated the 20 activated areas into three groups, which largely coincided with the cerebral lobes. The frontal group included the putative human FEF and SEF, and the parietal group PEF. The frontal and occipital groups exhibited the time course of activation with two peaks corresponding to neural responses during the encoding and execution phases, and the parietal group exhibited a single‐humped activation pattern corresponding to neural activity during the delay phase. The results suggest that the frontal regions are more associated with the execution of saccade, and the parietal regions with visuospatial representation, presumably in the sensory domain. Hum Brain Mapp 23:129–139, 2004. © 2004 Wiley‐Liss, Inc.
Variability of fMRI activation during a phonological and semantic language task in healthy subjects
Authors: Seghier Mohamed L. , Lazeyras François , Pegna Alan J. , Annoni Jean‐Marie , Zimine Ivan , Mayer Eugène , Michel Christoph M. , Khateb Asaid 
Published: July 2004

AbstractAssessing inter‐individual variability of functional activations is of practical importance in the use of functional magnetic resonance imaging (fMRI) in a clinical context. In this fMRI study we addressed this issue in 30 right‐handed, healthy subjects using rhyme detection (phonologic) and semantic categorization tasks. Significant activations, found mainly in the left hemisphere, concerned the inferior frontal gyrus, the superior/middle temporal gyri, the prefrontal cortex, the inferior parietal lobe, the superior parietal lobule/superior occipital gyrus, the pre‐central gyrus, and the supplementary motor area. Intensity/spatial analysis comparing activations in both tasks revealed an increased involvement of frontal regions in the semantic task and of temporo‐parietal regions in the phonologic task. The frequency of activation analyzed in nine regional subdivisions revealed a high inter‐subject variability but showed that the most frequently activated regions were the inferior frontal gyrus and the prefrontal cortex. Laterality indices, strongly lateralizing in both tasks, were slightly higher in the semantic (0.76 ± 0.19) than the phonologic task (0.66 ± 0.27). Frontal dominance indices (a measure of frontal vs. posterior left hemisphere dominance) indicated more robust frontal activations in the semantic than the phonologic task. Our study allowed the characterization of the most frequently involved foci in two language tasks and showed that the combination of these tasks constitutes a suitable tool for determining language lateralization and for mapping major language areas. Hum. Brain Mapping 23:140–155, 2004. © 2004 Wiley‐Liss, Inc.