990 resultados para Thayer, Ebenezer--1734-1792


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The research on mechanical effects of water-rock and soil interaction on deformation and failure of rocks and soils involves three aspects of mechanics, physics and chemistry. It is the cross between geochemistry and rock mechanics and soil mechanics. To sum up, the mechanical effects of water-rock and soil interaction is related to many complex processes. Research in this respect has been being an important forward field and has broad prospects. In connection with the mechanism of the effects of the chemical action of water-rock on deformation and failure of rocks and soils, the research significance, the present state, the developments in this research domain are summarized. Author prospects the future of this research. The research of the subject should be possessed of important position in studying engineering geology and will lead directly to a new understand on geological hazard and control research. In order to investigation the macroscopic mechanics effects of chemical kinetics of water-rock interaction on the deformation and failure, calcic rock, red sandstone and grey granite reacting chemically with different aqueous solution at atmospheric temperature and atmospheric pressure are uniaxially compressed. The quantitative results concerning the changes of uniaxially compressive strength and elastic modulus under different conditions are obtained. It is found that the mechanical effects of water on rock is closely related to the chemical action of water-rock or the chemical damage in rock, and the intensity of chemical damage is direct ratio to the intensity of chemical action in water-rock system. It is also found that the hydrochemical action on rock is time-dependent through the test. The mechanism of permeation and hydrochemical action resulting in failure of loaded rock mass or propagation of fractures in rocks would be a key question in rock fracture mechanics. In this paper, the fracture mechanical effects of chemical action of water-rock and their time- and chemical environment-dependent behavior in grey granite, green granite, grey sandstone and red sandstone are analyzed by testing K_(IC) and COD of rock under different conditions. It is found that: ①the fracture mechanical effect of chemical action of water-rock is outstanding and time-dependent, and high differences exist in the influence of different aqueous solution, different rocks, different immersion ways and different velocity of cycle flow on the fracture mechanical effects in rock. ②the mechanical effects of water-rock interaction on propagation of fractures is consistent with the mechanical effects on the peak strength of rock. ③the intensity of the mechanical fracture effects increases as the intensity of chemical action of water-rock increases. ④iron and calcium ion bearing mineral or cement in rock are some key ion or chemical composition, and especially iron ion-bearing mineral resulting in chemical action of water-rock to be provided with both positive and negative mechanical effects on rock. Through the above two tests, we suggest that primary factors influencing chemical damage in rock consist of the chemical property of rock and aqueous solution, the structure or homogeneity of rocks, the flow velocity of aqueous solution passing through rock, and cause of formation or evolution of rock. The paper explores the mechanism on the mechanical effects of water-rock interaction on rock by using the theory of chemistry and rock fracture mechanics with chemical damage proposed by author, the modeling method and the energy point of view. In this paper, the concept of absorbed suction between soil grains caused by capillary response is given and expounded, and the relation and basic distinction among this absorbed suction, surface tension and capillary pressure of the soil are analyzed and established. The law of absorbed suction change and the primary factors affecting it are approached. We hold that the structure suction are changeable along with the change of the saturation state in unsaturated soils. In view of this, the concept of intrinsic structure suction and variable structure suction are given and expounded, and this paper points out: What we should study is variable structure suction when studying the effective stress. By IIIy κHH's theory of structure strength of soils, the computer method for variable structure suction is analyzed, the measure method for variable structure suction is discussed, and it reach the conclusions: ①Besides saturation state, variable structure suction is affected by grain composition and packing patter of grains. ②The internal relations are present between structure parameter N in computing structure suction and structure parameter D in computing absorbed suction. We think that some problems exit in available principle of effective stress and shear strength theory for unsaturated soil. Based on the variable structure suction and absorbed suction, the classification of saturation in soil and a principle of narrow sense effective stress are proposed for unsaturated soils. Based on generalized suction, the generalized effective stress formula and a principle of generalized effective stress are proposed for unsaturated soils. The experience parameter χ in Bishop's effective stress formula is defined, and the principal factors influencing effective stress or χ. The primary factor affecting the effective stress in unsaturated soils, and the principle classifying unsaturated soils and its mechanics methods analyzing unsaturated soils are discussed, and this paper points out: The theory on studying unsaturated soil mechanics should adopt the micromechanics method, then raise it to macromechanics and to applying. Researching the mechanical effects of chemical action of water-soil on soil is of great importance to geoenvironmental hazard control. The texture of soil and the fabric of soil mass are set forth. The tests on physical and mechanical property are performed to investigate the mechanism of the positive and negative mechanical effects of different chemical property of aqueous solution. The test results make clear that the plastic limit, liquid limit and plasticity index are changed, and there exists both positive and negative effects on specimens in this test. Based on analyzing the mechanism of the mechanical effects of water-soil interaction on soil, author thinks that hydrochemical actions being provided with mechanical effects on soil comprise three kinds of dissolution, sedimentation or crystallization. The significance of these tests lie in which it is recognized for us that we may improve, adjust and control the quality of soils, and may achieve the goal geological hazard control and prevention.The present and the significance of the research on environmental effects of water-rock and soil interaction. Various living example on geoenvironmental hazard in this field are enumerated. Following above thinking, we have approached such ideals that: ①changing the intensity and distribution of source and sink in groundwater flow system can be used to control the water-rock and soil interaction. ②the chemical action of water-rock and soil can be used to ameliorate the physical and mechanical property of rocks and soils. Lastly, the research thinking and the research methods on mechanical effects and environmental effects of water-rock and soil interaction are put forward and detailed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This article discusses the way in which the Chopin Year of 1910 was celebrated in Wielkopolska. It presents a script prepared in the nineteenth century and shows similarities with celebrations of Mickiewicz and other Polish heroes and artists. Invariably used in such commemorations was a “symbolic capital” that made it easier to create an intergenerational code, thereby disseminating knowledge of national culture and history. A significant role was played in 1910 by a centenary panel, which produced “Guidelines for popular Chopin celebrations” and also many occasional, popular materials. Chopin’s induction into the national pantheon involved the use of audio material (vocal and instrumental concerts), verbal material (articles, poems, lectures and brochures) and also a visual code (anniversary window stickers, tableaux vivants or tableaux illuminés). Illuminated pictures – recommended by a catalogue of slides produced in Poznań – stimulated the imagination of the masses and served as a guide through the composer’s life and work, and their impact was enhanced by a commentary. Most of the living pictures were probably inspired by Henryk Siemiradzki’s canvas Chopin grający na fortepianie w salonie księcia Radziwiłła [Chopin playing the piano in Prince Radziwiłł’s salon] and Józef Męcina Krzesz’s painting Ostatnie akordy Chopina [Chopin’s last chords]. This combination of codes made it possible to create a model adapted to the times and to the expectations of a mass audience. The Chopin anniversary, in which admiration was inseparably intertwined with manipulation, was a pretext for strengthening the national identity.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Signaturas: *6, A-F4, G2, H-Z4, 2A-2Z4, 3A-3Z4, 4A-4Z4, 5A-5D4, 5E2, 5F4 ; *5, A-Z4, 2A-2Z4, 3A-3Y4, Z2, 4A4 ; *5, A-Z4, 2A-2Z4, 3A-3Z4, 4A-4N4, 4O5 ; *5, A-Z4, 2A-2Z4, 3A-3Z4, 4A-4O4, 4P2, 4Q1, 4R4 ; *5, A-Z4, 2A-2Z4, 3A-3M4, *2, A-S4.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En Tomo V. 2 h. de grabados calcográficos representando monedas de Huesca.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

After the 1980s it is diffi cult, following stylistic criteria, to draw a map of contemporary academic music. All styles are compossible, and all are practiced. In this context, the geographical entity “South of Italy” does not stand out for a musical identity with special technical-stylistic features. Rather, at a socio-cultural level, the South remains today – in music no less than in all areas where there is a gap between top development and stagnation – a land of emigrants: six out of the seven composers treated (Ivan Fedele, Giuseppe Colardo, Rosario Mirigliano, Giuseppe Soccio, Nicola Cisternino, Biagio Putignano, Paolo Aralla) live in the North of Italy. The positive aspect of this is the affi nity of the South with the transnational and superstructural community of contemporary music, which from European and Western has now become almost global. The composers under consideration belong to the generation of the ‘50s, rooted in the serial and post-serial movements (from which Franco Donatoni, Luciano Berio, Luigi Nono, Salvatore Sciarrino, Giacinto Scelsi, are the principals models, to mention only the Italians), dipped in the general phenomenon of timbrism (particularly spectralism), and acquainted with electronics. They draw from these sources various instruments of compositional technique and aspects of their poetics. In particular these composers, active from the ‘80s, develop new ways of construction of the temporal form of music. They share the goal to establish a new continuity, different from the tonal one but at the same time transcending the serial and post-serial disintegration and fragmentation. The primary means to this end is a new enhancement of the category of fi gure, as a clear and distinct, recognizable aggregate of pitches, intervals, register, durations, timbre, articulation, dynamics, and texture. Each composer elaborates the atonal fi gural material in different ways, emphasizing one aspect or another. For example, Fedele (1953) is a master in the management of form per se, Colardo (1953) in the activation of disturbed harmonic effects, Mirigliano (1950) in the creation of a slight tension from the smallest vibrations of sound, Soccio (1950) in the set up of movement by means of accumulations and discharges of energy, Cisternino (1957) in a Cagean-Scelsian emphasis on sound as such, Putignano (1960) in the suspension of time through the succession and transformation of images, Aralla (1960) in the foundation of form from below, from the concreteness of sound.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The musicological tradition places Liszt’s Sonata in B minor within the sphere of compositions inspired by the Faustian myth. Its musical material, its structure and its narrative exhibit certain similarities to the ‘Faust’ Symphony. Yet there has appeared a diff erent and, one may say, a rival interpretation of Sonata in B minor. What is more, it is well-documented from both a musical and a historical point of view. It has been presented by Hungarian pianist and musicologist Tibor Szász. He proposes the thesis that the Sonata in B minor has been in fact inspired by Milton’s Paradise Lost, with its three protagonists: Adam, Satan and Christ. He fi nds their illustrations and even some key elements of the plot in the Sonata’s narrative. But yet Milton’s Paradise Lost and Goethe’s Faust are both stories of the Fall and Salvation, of the cosmic struggle between good and evil. The triads of their protagonists – Adam and Eve, Satan, and Christ; Faust, Mephisto and Gretchen – are homological. Thus both interpretations of the Sonata, the Goethean and the Miltonian, or, in other words, the Faustian and the Luciferian, are parallel and complementary rather than rival. It is also highly probable that both have had their impact on the genesis of the Sonata in B minor.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

http://www.archive.org/details/samsonoccom00loverich/

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Controlling the mobility pattern of mobile nodes (e.g., robots) to monitor a given field is a well-studied problem in sensor networks. In this setup, absolute control over the nodes’ mobility is assumed. Apart from the physical ones, no other constraints are imposed on planning mobility of these nodes. In this paper, we address a more general version of the problem. Specifically, we consider a setting in which mobility of each node is externally constrained by a schedule consisting of a list of locations that the node must visit at particular times. Typically, such schedules exhibit some level of slack, which could be leveraged to achieve a specific coverage distribution of a field. Such a distribution defines the relative importance of different field locations. We define the Constrained Mobility Coordination problem for Preferential Coverage (CMC-PC) as follows: given a field with a desired monitoring distribution, and a number of nodes n, each with its own schedule, we need to coordinate the mobility of the nodes in order to achieve the following two goals: 1) satisfy the schedules of all nodes, and 2) attain the required coverage of the given field. We show that the CMC-PC problem is NP-complete (by reduction to the Hamiltonian Cycle problem). Then we propose TFM, a distributed heuristic to achieve field coverage that is as close as possible to the required coverage distribution. We verify the premise of TFM using extensive simulations, as well as taxi logs from a major metropolitan area. We compare TFM to the random mobility strategy—the latter provides a lower bound on performance. Our results show that TFM is very successful in matching the required field coverage distribution, and that it provides, at least, two-fold query success ratio for queries that follow the target coverage distribution of the field.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A novel approach for real-time skin segmentation in video sequences is described. The approach enables reliable skin segmentation despite wide variation in illumination during tracking. An explicit second order Markov model is used to predict evolution of the skin color (HSV) histogram over time. Histograms are dynamically updated based on feedback from the current segmentation and based on predictions of the Markov model. The evolution of the skin color distribution at each frame is parameterized by translation, scaling and rotation in color space. Consequent changes in geometric parameterization of the distribution are propagated by warping and re-sampling the histogram. The parameters of the discrete-time dynamic Markov model are estimated using Maximum Likelihood Estimation, and also evolve over time. Quantitative evaluation of the method was conducted on labeled ground-truth video sequences taken from popular movies.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This work illustrates the influence of wind forecast errors on system costs, wind curtailment and generator dispatch in a system with high wind penetration. Realistic wind forecasts of different specified accuracy levels are created using an auto-regressive moving average model and these are then used in the creation of day-ahead unit commitment schedules. The schedules are generated for a model of the 2020 Irish electricity system with 33% wind penetration using both stochastic and deterministic approaches. Improvements in wind forecast accuracy are demonstrated to deliver: (i) clear savings in total system costs for deterministic and, to a lesser extent, stochastic scheduling; (ii) a decrease in the level of wind curtailment, with close agreement between stochastic and deterministic scheduling; and (iii) a decrease in the dispatch of open cycle gas turbine generation, evident with deterministic, and to a lesser extent, with stochastic scheduling.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose – This paper aims to assess the actual contribution to organisational change of management and leadership development (MLD) activity for middle managers (MMs) in public service organisations (PSOs). Design/methodology/approach – Using the case study approach, the paper compares the content and outcomes of management and leadership training interventions for MMs in two large PSOs. The organisations, a fire brigade and a train operating company, are leaders in their sectors with respect to management development and “modernisation” of their services. Findings – The paper demonstrates how, in one case, MM development was largely an exercise in regulatory compliance, with little effect on individual MMs' performance or organisational outcomes. The second case demonstrates how MMs were effectively trained to enforce specific human resource policies which contributed to the successful implementation of top-down strategy yet paid little attention to the potential leadership role of MMs. Research limitations/implications – The paper highlights the need for further contextualised research at organisational level into the outcomes of MLD, especially in terms of different public service contexts. Practical implications – The paper demonstrates the dangers of designing and implementing development programmes without sufficient regard to professional practice and the realities of managerial discretion in PSOs. Originality/value – The paper provides an in-depth and contextualised insight into the conditions for success and failure in management development interventions in PSOs.