993 resultados para 124-773B
Resumo:
Uniform field steady-state ionization currents were measured in dry air as a function of N at constant E/N (E is the electric field strength and N the gas number density) and constant electrode separation d for 14·13 × 10-16 less-than-or-eq, slant E/N less-than-or-eq, slant 282·5 × 10-16 V cm2. Uniform field sparking potentials were also measured for Nd range 1·24 × 1016 less-than-or-eq, slant Nd less-than-or-eq, slant 245 × 1016 cm-2. The ratio of the Townsend primary ionization coefficient α to N, α/N, was found to depend on E/N only. The secondary coefficients were also evaluated for aluminium and gold-plated electrodes for the above range of E/N. Measurements of the sparking potentials showed that Paschen's law is not obeyed in air at values of Nd near and below the Paschen minimum.
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The driving force behind this study is the gap between the reality of the firms engaged in project business and the available studies covering project management and business process development. Previous studies show that project-based organizations were ‘immature’ in terms of the project-management ‘maturity model’, as few firms were found to be optimizing processes. Even within those, very little attention was paid to combine inter-organizational and intra-organizational perspectives. In this study an effort is made to elaborate some thoughts and views on project management, which interrelate firms’ external and internal activities. In line with the integration, the dissertation uses an approach to the management of project-business interdependencies in the networks of actors, activities and resources. Firstly, the study develops an understanding for inter-organizational perspectives by exploring the complementarities of process activities in the basic development of project business. It presents a framework that is elaborated on the basis of the reciprocal interactions of activities within and outside the organization—thus providing a coherent basis for continuous business-process improvement. In addition, the study presents new tools that can be used to develop project-business processes in each of its functional areas. The research demonstrates how project-business activities can be optimized using the right resources at the right time with the right actors and the right actions. The selected five articles included in this dissertation explain the basic framework for the development of project business. Each paper covers various aspects of inter-organizational and intra-organizational perspectives for project management. The study develops a valuable and procedural model for business-process improvement using the Delphi method that can be used not only in academia but also as a guide for practitioners that takes them through a series of well-defined steps when making informed, consistent and efficient changes to their business processes.
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We study an abelian Chern-Simons theory on a five-dimensional manifold with boundary. We find it to be equivalent to a higher-derivative generalization of the abelian Wess-Zumino-Witten model on the boundary. It contains a U(1) current algebra with an operational extension.
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Since the emergence of service marketing, the focus of service research has evolved. Currently the focus of research is shifting towards value co-created by the customer. Consequently, value creation is increasingly less fixed to a specific time or location controlled by the service provider. However, present service management models, although acknowledging customer participation and accessibility, have not considered the role of the empowered customer who may perform the service at various locations and time frames. The present study expands this scope and provides a framework for exploring customer perceived value from a temporal and spatial perspective. The framework is used to understand and analyse customer perceived value and to explore customer value profiles. It is proposed that customer perceived value can be conceptualised as a function of technical, functional, temporal and spatial value dimensions. These dimensions are suggested to have value-increasing and value-decreasing facets. This conceptualisation is empirically explored in an online banking context and it is shown that time and location are more important value dimensions relative to the technical and functional dimensions. The findings demonstrate that time and location are important not only in terms of having the possibility to choose when and where the service is performed. Customers also value an efficient and optimised use of time and a private and customised service location. The study demonstrates that time and location are not external elements that form the service context, but service value dimensions, in addition to the technical and functional dimensions. This thesis contributes to existing service management research through its framework for understanding temporal and spatial dimensions of perceived value. Practical implications of the study are that time and location need to be considered as service design elements in order to differentiate the service from other services and create additional value for customers. Also, because of increased customer control and the importance of time and location, it is increasingly relevant for service providers to provide a facilitating arena for customers to create value, rather than trying to control the value creation process. Kristina Heinonen is associated with CERS, the Center for Relationship Marketing and Service Management at the Swedish School of Economics and Business Administration
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A computational scheme has been developed for strongly interacting systems wherein the intermolecular interaction is introduced as a charge-induced-dipole term. Within this approximation, the model Hamiltonian is exactly solved using a valence-bond basis. The validity of the scheme has been checked by use of exact calculations on small model systems. The method has been applied to finite polyenes to study the shifts in the ground-state energies and dipole-allowed excited-state energies in the presence of neighbors. Our calculations show a red shift in the optical gap of the infinite polyene by 0.124 eV, which is rather small compared to the experimental red shift. This is traced to the larger inaccuracy in the calculated shift in the excited state. The calculated shift in the ground-state energies are more accurate and hence the method is better suited for studying the effect of intermolecular interactions on the properties of the ground state.
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We report preliminary experiments on the ternary-liquid mixture, methyl ethyl ketone (MEK)+water (W)+secondary butyl alcohol (sBA)-a promising system for the realization of the quadruple critical point (QCP). The unusual tunnel-shaped phase diagram shown by this system is characterized and visualized by us in the form of a prismatic phase diagram. Light-scattering experiments reveal that (MEK+W+sBA) shows near three-dimensional-Ising type of critical behavior near the lower critical solution temperatures, with the susceptibility exponent (gamma) in the range of 1.217 <=gamma <= 1.246. The correlation length amplitudes (xi(o)) and the critical exponent (nu) of the correlation length (xi) are in the ranges of 3.536 <=xi(o)<= 4.611 A and 0.619 <=nu <= 0.633, respectively. An analysis in terms of the effective susceptibility exponent (gamma(eff)) shows that the critical behavior is of the Ising type for MEK concentrations in the ranges of 0.1000 <= X <= 0.1250 and X >= 0.3000. But, for the intermediate range of 0.1750 <= X < 0.3000, the system shows a tendency towards mean-field type of critical behavior. The advantages of the system (MEK+W+sBA) over the system (3-methylpyridine+water+heavy water+potassium Iodide) for the realization of a QCP are outlined.
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The system 3-methylpyridine(3MP)+water(H2O)+NaBr has been the subject of an intense scientific debate since the work of Jacob [Phys. Rev. E. 58, 2188 (1988)] and Anisimov [Phys. Rev. Lett. 85, 2336 (2000)]. The crossover critical behavior of this system seemed to show remarkable sensitivity to the weight fraction (X) of the ionic impurity NaBr. In the range X <= 0.10 the system displayed Ising behavior and a pronounced crossover to mean-field behavior in the range 0.10 <= X <= 0.16. A complete mean-field behavior was observed at X=0.17, a result that was later attributed to the existence of long-living nonequilibrium states in this system [Kostko , Phys. Rev. E. 70, 026118 (2004)]. In this paper, we report the near-critical behavior of osmotic susceptibility in the isotopically related ternary system, 3MP+heavy water(D2O)+NaBr. Detailed light-scattering experiments performed at exactly the same NaBr concentrations as investigated by Jacob reveal that the system 3MP+D2O+NaBr shows a simple Ising-type critical behavior with gamma similar or equal to 1.24 and nu similar or equal to 0.63 over the entire NaBr concentration range 0 <= X <= 0.1900. The crossover behavior is predominantly nonmonotonic and is completed well outside the critical domain. An analysis in terms of the effective susceptibility exponent (gamma(eff)) reveals that the crossover behavior is nonmonotonic for 0 <= X <= 0.1793 and tends to become monotonic for X > 0.1793. The correlation length amplitude xi(o), has a value of similar or equal to 2 A for 0.0250 <= X <= 0.1900, whereas for X=0, xi(o)similar or equal to 3.179 A. Since isotopic H -> D substitution is not expected to change the critical behavior of the system, our results support the recent results obtained by Kostko [Phys. Rev. E. 70, 026118 (2004)] that 3MP+H2O+NaBr exhibits universal Ising-type critical behavior typical for other aqueous solutions.
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While extant studies have greatly advanced our understanding of corruption, we still know little of the processes through which specific practices or events come to be labeled as corruption. In a time when public attention devoted to corruption and other forms of corporate misbehavior has exploded, this thesis raises – and seeks to answer – crucial questions related to how the phenomenon is socially and discursively constructed. What kinds of struggles are manifested in public disputes about corruption? How do constructions of corruption relate with broader conceptions of (il)legitimacy in and around organizations? What are the discursive dynamics involved in the emergence and evolution of corruption scandals? The thesis consists of four essays that each employ different research designs and tackle these questions in slightly different theoretical and methodological ways. The empirical focus is on the media coverage of a number of significant and widely discussed scandals in Norway in the period 2003-2008. By illuminating crucial processes through which conceptions of corruption were constructed, reproduced, and transformed in these scandals, the thesis seeks to paint a more nuanced picture of corruption than what is currently offered in the literature. In particular, the thesis challenges traditional conceptions of corruption as a dysfunctional feature of organizations in and of itself by emphasizing the ambiguous, temporal, context-specific, and at times even contradictory features of corruption in public discussions.
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The temperature (T) and electric field-to-gas pressure (E/P) dependences of the rate coefficientk for the reaction SF 6 � +SOF4rarrSOF 5 � +SF5 have been measured. ForT<270>k approaches a constant of 2.1×10�9 cm3/s, and for 433>T>270 K,k decreases withT according tok (cm3/s)=0.124 exp [�3.3 lnT(K)]. ForE/Pk has a constant value of about 2.5×10�10 cm3/s, and for 130 V/cm·torr>E/P>60 V/cm·torr, the rate is approximately given byk (cm3/s)sim7.0×10�10 exp (�0.022E/P). The measured rate coefficient is used to estimate the influence of this reaction on SOF4 production from negative, point-plane, glow-type corona discharges in gas mixtures containing SF6 and at least trace amounts of O2 and H2O. A chemical kinetics model of the ion-drift region in the discharge gap is used to fit experimental data on SOF4 yields assuming that the SF 6 � +SOF4 reaction is the predominant SOF4 loss mechanism. It is found that the contribution of this reaction to SOF4 destruction falls considerably below the estimated maximum effect assuming that SF 6 � is the predominant charge carrier which reacts only with SOF4. The results of this analysis suggest that SF 6 � is efficiently deactivated by other reactions, and the influence of SF 6 � +SOF4 on SOF4 production is not necessarily more significant than that of other slower secondary processes such as gas-phase hydrolysis
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Among the various cathode materials studied for Li-ion batteries over the past many years, spinet LiMn2O4 is found to be one of the most attractive materials. Nanoparticles of the electrode materials sustain high rate capability due to large surface to volume ratio and small diffusion path length. Nanoparticles of spinel LiMn2O4 have been synthesized by microwave hydrothermal technique using prior synthesized amorphous MnO2 and LiOH. The phase and purity of spinel LiMn2O4 are confirmed by powder X-ray diffraction. The morphological studies have been investigated using field emission scanning electron microscopy and high-resolution transmission electron microscopy. The electrochemical performances of the material for Li insertion/extraction are evaluated by cyclic voltammetry, galvanostatic charge-discharge cycling and AC impedance studies. The initial discharge capacity is found to be about 89 mAh g(-1) at current density of 21 mA g(-1). (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
The mutual diffusion coefficients for binary liquid systems of benzene-n-alkyl alcohol at various compositions have been determined by the diaphragm cell method at 28-degrees-C. The alcohols used were the members of n-paraffinic alcohols ranging from C1 to C8. The maximum possible experimental error is 14%. The data were fitted with a generalized correlation, giving the deviation from the experimental data to within 2.75%, on average.
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Korpien puustorakenteen palautumisen nopeus ja ennallistettujen kohteiden kehitys on huonosti tunnettua. Monet tutkimukset ovat osoittaneet, että korvet ovat lajistollisen monimuotoisuuden keskittymiä boreaalisessa vyöhykkeessä. Korvet ovat usein merkittäviä lahopuukeskittymiä, joten niillä on iso vaikutus lahottajalajistolle. Valtaosa suojelualu- eiden korvista Etelä-Suomessa on ojitettu ja korpien puustorakenne on metsätalouden muovaamaa ja yksipuolistamaa. Korpien puustorakennetta tutkittiin kahdella erillisellä tutkimusalueella, jotka sijaitsevat Etelä-Suomessa. Työn tavoit- teena oli selvittää luonnontilaisten ja ennallistettujen korpien puuston rakenteellista monimuotoisuutta sekä ennallista- mistoimien vaikutuksia Evon suojelumetsässä ja Liesjärven kansallispuistossa. Molemmat alueet ovat olleet aikaisem- min metsänhoidon piirissä. Evolta valittiin tarkasteluun ennallistettuja ja luonnontilaisen kaltaisia korpia: 12 ennallis- tettua koealaa ja 16 luonnontilaisen kaltaista koealaa. Liesjärveltä valittiin tarkasteluun ennallistettu Soukonkorpi, jossa oli 15 koealaa. Koealat olivat pinta-alaltaan neljä aaria. Evon tutkimusalueella maastomittaukset on tehty kesällä 2002 ja 2010. Liesjärven tutkimusalueella maastomittaukset on tehty vuosina 1995–2010. Tarkastellut muuttujat olivat elävän puuston määrä ja puulajisuhteet, lahopuun määrä ja laatu (lahopuutyyppi, läpimittaluokka, lahoaste ja puulaji). Lahopuuston määrää ja laatua sekä lahopuuston ja elävän puuston suhdetta kuvaavien muuttujien välisiä eroja testattiin ei-parametrisellä Kolmogorov-Smirnov-testillä. Evon ja Liesjärven tutkimusalueiden ennallistamistoimien yhtenä tavoitteena oli lahopuumäärien lisääminen ja laho- puun monipuolistaminen. Lahopuun lisäämisessä on onnistuttu molemmilla tutkimusalueilla. Ennallistamisen jälkeen lahopuumäärä kasvoi Evolla kolminkertaiseksi 8 vuodessa. Lahopuuta oli ennallistamisen jälkeen keskimäärin 71 m³/ha. Sen sijaan Evon luonnontilaisen kaltaisissa korvissa lahopuumäärä pysyi keskimäärin samana (28 m³/ha) tar- kastelujakson aikana. Liesjärvellä lahopuumäärä kasvoi ennallistamisen jälkeen noin kuusinkertaiseksi 15 vuodessa. Lahopuuta oli ennallistamisen jälkeen keskimäärin 124 m³/ha. Suuriläpimittaisen (? 30 cm) lahopuun määrä kasvoi huomattavasti ennallistamisen jälkeen molemmilla tutkimusalueilla. Suuriläpimittaisen lahopuun määrä kasvoi Evolla noin 12-kertaiseksi ja Liesjärvellä noin 9-kertaiseksi. Lahopuun määrä ja laatu vaihtelivat suuresti ennallistettujen ja luonnontilaisen kaltaisten korpien välillä. Evolta löytyi lahopuustoltaan runsaita ja monipuolisia korpia, mutta myös korpia, joiden lahopuusto on luonnontilaisiin korpiin ver- rattuna määrältään vähäistä ja laadultaan yksipuolista. Liesjärvellä koealojen lahopuumäärät poikkesivat suuresti toisis- taan. Valtaosalla koealoista lahopuusto oli kuitenkin runsaampaa ja monimuotoisempaa kuin talousmetsissä yleensä. Molemmilla tutkimusalueilla ennallistetut korvet muistuttavat nyt puustorakenteeltaan lahopuun osalta enemmän luon- nontilaisia korpia kuin ennen ennallistamista. Ilman ennallistamistoimia lahopuumäärän kasvu olisi todennäköisesti ollut hidasta. Evolla ennallistettujen ja luonnontilaisen kaltaisten korpien välillä oli tilastollisesti merkitseviä eroja suuriläpimittaisen lahopuun ja tuoreimpien lahoasteiden (1 ja 2) määrässä. Valtaosalla korvista oli lahopuuta vähintään 20 m³/ha. Metsäaluetasolla keskimäärin 20–30 m³/ha järeää, vaihtelevanlaatuista lahopuuta näyttäisi aikaisempien tutkimusten mukaan täyttävän useimpien saproksyylilajien elinympäristövaatimukset Etelä-Suomessa.
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Engl. summary: Studies on conditioning and mechanical dewatering of waste water sludge