868 resultados para Saw filing.
Resumo:
The dissertation discusses the history of the book and the Enlightenment in Finland by studying the reception and diffusion of eighteenth-century books and by approaching the discourse on the Enlightenment in Finnish source material. The methods used relate to historian Robert Darnton s studies on eighteenth-century print culture and his analyses of the relations between print culture and society. The study is based on diverse eighteenth-century sources: books, pamphlets and dissertations, bibliographies, book auction protocols, parliamentary documents, estate inventory deeds, newspapers, letters, lectures, memoirs and commonplace books. By the end of the eighteenth century, book production had increased and secular literature had begun to challenge the dominance of religious literature. The books of the Enlightenment belonged to the new literature that found its way into Finnish book collections previously dominated by religious literature. Enlightenment literature is not a set selection of books but rather diverse works from different genres. Thus the study introduces a variety of printed material, from philosophical tracts and textbooks to novels and pornography. In the case of books of the Enlightenment, the works of French Voltaire and German Christian Wolff were among the most widely read and circulated books in Finland. First and foremost, the Enlightenment was an era of intellectual debate. These debates carried strong criticism of the prevailing systems of thought. Enlightenment ideas challenged the Lutheran society of Sweden and especially its sense of conformity. Contemporaries saw many of the books of the Enlightenment as vessels of new ideas and criticism. Furthermore, this kind of print material was interpreted as being dangerous for uneducated readers. Belonging to a certain estate and social class had a major impact on individuals reading habits and their acquisition of books. One specific social group stands out in the Finnish source material: the officers at the Sveaborg naval fortress possessed and distributed Enlightenment books more than the members of any other social class. Other essential social groups were scholars, the nobility and the clergy, who took part in debates concerning the ideas and benefits of the Enlightenment. In the Finnish debates at the time, the concept of Enlightenment involved three primary notions. Firstly, it referred to the French philosophers, les philosophes, and to their works as well as to the social changes that took place during the French revolution. It also carried the idea of philosophical light or the light of reason, in a sense similar to Immanuel Kant s writings. Most importantly, it referred to a belief in progress and to a trust in true knowledge that would supercede ignorance and fanaticism. Hence, it is impossible to speak about the Enlightenment era in the Swedish realm without such concepts as reason, benefit or progress. These concepts likewise marked the books of the Enlightenment in eighteenth-century Finland.
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At the the heart of this study can be seen the dual concern of how the nation is represented as a categorical entity and how this is put to use in everyday social interactions.This can be seen as a reaction to the general approach to categorisation and identity functions that tend to be reified and essentialized within the social sciences. The empirical focus of this study is the Isle of Man, a crown dependency situated geographically central within the British Isles while remaining political outside the United Kingdom. The choice of this site was chosen explicitly as ‘notions of nation’ expressed on the island can be seen as being contested and ephemerally unstable. To get at these ‘notions of nation’ is was necessary to choose specific theoretical tools that were able to capture the wider cultural and representational domain while being capable of addressing the nuanced and functional aspects of interaction. As such, the main theoretical perspective used within this study was that of critical discursive psychology which incorporates the specific theoretical tools interpretative repertoires, ideological dilemmas and subject positions. To supplement these tools, a discursive approach to place was taken in tandem to address the form and function of place attached to nationhood. Two methods of data collection were utilized, that of computer mediated communication and acquaintance interviews. From the data a number of interpretative repertoires were proposed, namely being, essential rights, economic worth, heritage claims, conflict orientation, people-as-nation and place-as-nation. Attached to such interpretative repertoires were the ideological dilemmas region vs. country, people vs. place and individualism vs. collectivism. The subject positions found are much more difficult to condense, but the most significant ones were gender, age and parentage. The final focus of the study, that of place, was shown to be more than just an unreflected on ‘container’ of people but was significant in terms of the rhetorical construction of such places for how people saw themselves and the discursive function of the particular interaction. As such, certain forms of place construction included size, community, temporal, economic, safety, political and recognition. A number of conclusions were drawn from the above which included, that when looking at nation categories we should take into account the specific meanings that people attach to such concepts and to be aware of the particular uses they are put to in interaction. Also, that it is impossible to separate concepts neatly, but it is necessary to be aware of the intersection where concepts cross, and clash, when looking at nationhood.
Resumo:
Cutting of Y2O3-doped TZP rods by a low-speed diamond saw introduces an unidentified, metastable phase X (x-ZrO2) coexisting with the tetragonal (t-ZrO2) and the monoclinic (m-ZrO2) phases initially present in the sample. Further mechanical deformation of the cut surface by indentation or polishing sustains the x-ZrO2. Chemical etching removes the x-ZrO2 and increases the m-ZrO2content.
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Using audio-recorded data from cognitive-constructivist psychotherapy, the article shows a particular institutional context in which successful professional action does not adhere to the pattern of affective neutrality which Parsons saw as an inherent component of medicine and psychotherapy. In our data, the professional’s non-neutrality functions as a tool for achieving institutional goals. The analysis focuses on the psychotherapist’s actions that convey a critical stance towards a third party with whom the patient has experienced problems. The data analysis revealed two practices of this kind of critique: (1) the therapist can confirm the critique that the patient has expressed or (2) return to the critique from which the patient has focused away. These actions are shown to build grounds for the therapist’s further actions that challenge the patient’s dysfunctional beliefs. The article suggests that in the case of psychotherapy, actions that as such might be seen as apparent lapses from the neutral professional role can in their specific context perform the task of the institution at hand.
Resumo:
The efficiency of acoustooptic (AO) interaction in YZ-cut proton exchanged (PE) LiNbO3 waveguides is theoretically analysed by determining the overlap between the optical and acoustic field distributions. The present analysis takes into account the perturbed SAW field distribution due to the presence of the PE layer on the LiNbO3 substrate determined by the rigorous layered medium approach. The overlap is found to be significant upto very high acoustic frequencies of the order of 5 GHz, whereas in the earlier analysis by vonHelmolt and Schaffer [6] for diffused waveguides, it was shown that the overlap integral rolls down to nearly zero at this high frequency range.
Resumo:
SAW matched filter is commonly used in spread spectrum communication receivers in order to maximize the SNR prior to detection, At times the receiver would be a mobile one while the signal is processed at the IF level, In that case frequency deviations due to Doppler shift or temperature dependence of the acoustic medium used for SAW device would, severely effect it's performance, The impact of these errors on the receiver performance is analyzed on a generalised basis.
Resumo:
We report here an easily reversible set-reset process in a new Ge15Te83Si2 glass that could be a promising candidate for phase change random access memory applications. The I-V characteristics of the studied sample show a comparatively low threshold electric field (E-th) of 7.3 kV/cm. Distinct differences in the type of switching behavior are achieved by means of controlling the on state current. It enables the observation of a threshold type for less than 0.7 mA beyond memory type (set) switching. The set and reset processes have been achieved with a similar magnitude of 1 mA, and with a triangular current pulse for the set process and a short duration rectangular pulse of 10 msec width for the reset operation. Further, a self-resetting effect is seen in this material upon excitation with a saw-tooth/square pulse, and their response of leading and trailing edges are discussed. About 6.5 x 10(4) set-reset cycles have been undertaken without any damage to the device. (C) 2011 American Institute of Physics. doi: 10.1063/1.3574659]
Resumo:
A set of finite elements (FEs) is formulated to analyze wave propagation through inhomogeneous material when subjected to mechanical, thermal loading or piezo-electric actuation. Elastic, thermal and electrical properties of the materials axe allowed to vary in length and thickness direction. The elements can act both as sensors and actuators. These elements are used to model wave propagation in functionally graded materials (FGM) and the effect of inhomogeneity in the wave is demonstrated. Further, a surface acoustic wave (SAW) device is modeled and wave propagation due to piezo-electric actuation from interdigital transducers (IDTs) is studied.
Resumo:
The program SuSeFLAV is introduced for computing supersymmetric mass spectra with flavour violation in various supersymmetric breaking scenarios with/without see-saw mechanism. A short user guide summarizing the compilation, executables and the input files is provided.
Resumo:
The objective of this work is to confirm the possibility of utilization of PolyVinyliDeneFlouride (PVDF) films in MEMS based microactuator for microjet applications. A membrane type microactuator is designed, developed, packaged and tested. The microactuator consists of PVDF film attached to thin Silicon diaphragm. As the voltage difference is applied across it, due to the piezoelectric behaviour, it deforms primarily in d31 mode, which in turn deflects the diaphragm. Using finite element methods, coupled field analysis is carried out to optimize the dimensions of the actuator with respect to the output force and input voltage. A cavity with a square diaphragm of 1mm×1mm×5μm is realized using standard microfabrication technique. 50μm thick PVDF film, cut with special dicing saw, is glued inside the metalized cavity using low stress, conductive, room temperature cured epoxy. The 3mm×3mm×0.675mm actuator die is packaged using Chip-On-Board technique in conjunction with low temperature soldering for taking the connections. The micro-actuator is tested in both actuation and sensing mode. The developed actuator is proposed to use with micro nozzle to study the utilization in drug delivery system.
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The RecA filament formed on double-stranded (ds) DNA is proposed to be a functional state analogous to that generated during the process of DNA strand exchange. RecA polymerization and de-polymerization on dsDNA is governed by multiple physiological factors. However, a comprehensive understanding of how these factors regulate the processes of polymerization and de-polymerization of RecA filament on dsDNA is still evolving. Here, we investigate the effects of temperature, pH, tensile force, and DNA ends (in particular ssDNA overhang) on the polymerization and de-polymerization dynamics of the E. coli RecA filament at a single-molecule level. Our results identified the optimal conditions that permitted spontaneous RecA nucleation and polymerization, as well as conditions that could maintain the stability of a preformed RecA filament. Further examination at a nano-meter spatial resolution, by stretching short DNA constructs, revealed a striking dynamic RecA polymerization and de-polymerization induced saw-tooth pattern in DNA extension fluctuation. In addition, we show that RecA does not polymerize on S-DNA, a recently identified novel base-paired elongated DNA structure that was previously proposed to be a possible binding substrate for RecA. Overall, our studies have helped to resolve several previous single-molecule studies that reported contradictory and inconsistent results on RecA nucleation, polymerization and stability. Furthermore, our findings also provide insights into the regulatory mechanisms of RecA filament formation and stability in vivo.
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The magnetic saw effect, induced by the Lorentz force generated due to the application of a series of electromagnetic ( EM) pulses, can be utilized to cut a metallic component containing a pre-existing cut or crack. By combining a mechanical force with the Lorentz force, the cut can be propagated along any arbitrary direction in a controlled fashion, thus producing an `electromagnetic jigsaw', yielding a novel tool-less, free-formed manufacturing process, particularly suitable for hard-to-cut metals. This paper presents validation of the above concept based on a simple analytical model, along with experiments on two materials - Pb foil and steel plate. (C) 2013 The Authors. Published by Elsevier B.V. Selection and/or peer-review under responsibility of Professor Bert Lauwers
Resumo:
The average time tau(r) for one end of a long, self-avoiding polymer to interact for the first time with a flat penetrable surface to which it is attached at the other end is shown here to scale essentially as the square of the chain's contour length N. This result is obtained within the framework of the Wilemski-Fixman approximation to diffusion-limited reactions, in which the reaction time is expressed as a time correlation function of a ``sink'' term. In the present work, this sink-sink correlation function is calculated using perturbation expansions in the excluded volume and the polymer-surface interactions, with renormalization group methods being used to resum the expansion into a power law form. The quadratic dependence of tau(r) on N mirrors the behavior of the average time tau(c) of a free random walk to cyclize, but contrasts with the cyclization time of a free self-avoiding walk (SAW), for which tau(r) similar to N-2.2. A simulation study by Cheng and Makarov J. Phys. Chem. B 114, 3321 (2010)] of the chain-end reaction time of an SAW on a flat impenetrable surface leads to the same N-2.2 behavior, which is surprising given the reduced conformational space a tethered polymer has to explore in order to react. (C) 2014 AIP Publishing LLC.
Resumo:
When a binary liquid is confined by a strongly repulsive wall, the local density is depleted near the wall and an interface similar to that between the liquid and its vapor is formed. This analogy suggests that the composition of the binary liquid near this interface should exhibit spatial modulation similar to that near a liquid-vapor interface even if the interactions of the wall with the two components of the liquid are the same. The Guggenheim adsorption relation quantifies the concentrations of two components of a binary mixture near a liquid-vapor interface and qualitatively states that the majority (minority) component enriches the interface for negative (positive) mixing energy if the surface tensions of the two components are not very different. From molecular dynamics simulations of binary mixtures with different compositions and interactions we find that the Guggenheim relation is qualitatively satisfied at wall-induced interfaces for systems with negative mixing energy at all state points considered. For systems with positive mixing energy, this relation is found to be qualitatively valid at low densities, while it is violated at state points with high density where correlations in the liquid are strong. This observation is validated by a calculation of the density profiles of the two components of the mixture using density functional theory with the Ramakrishnan-Yussouff free-energy functional. Possible reasons for the violation of the Guggenheim relation are discussed.
Resumo:
We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft colloidal material-star polymers. In our study, polystyrene-grafted gold nanoparticles with functionality f = 70 were mixed with linear polystyrene (PS) of two different molecular weights for obtaining two PGNP: PS size ratios, xi = 0.14 and 2.76 (where, xi = M-g/M-m, M-g and M-m being the molecular weights of grafting and matrix polymers, respectively). The experimental structure factor of PGNPs could be modeled with an effective potential (Model-X), which has been found to be widely applicable for star polymers. Similarly, the structure factor of the blends with xi = 0.14 could be modeled reasonably well, while the structure of blends with xi = 2.76 could not be captured, especially for high density of added polymers. A model (Model-Y) for effective interactions between PGNPs in a melt of matrix polymers also failed to provide good agreement with the experimental data for samples with xi = 2.76 and high density of added polymers. We tentatively attribute this anomaly in modeling the structure factor of blends with xi = 2.76 to the questionable assumption of Model-X in describing the added polymers as star polymers with functionality 2, which gets manifested in both polymer-polymer and polymer-PGNP interactions especially at higher fractions of added polymers. The failure of Model-Y may be due to the neglect of possible many-body interactions among PGNPs mediated by matrix polymers when the fraction of added polymers is high. These observations point to the need for a new framework to understand not only the structural behavior of PGNPs but also possibly their dynamics and thermo-mechanical properties as well. (C) 2015 AIP Publishing LLC.