932 resultados para Polystyrene Sphere
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Using path integrals, we derive an exact expression-valid at all times t-for the distribution P(Q,t) of the heat fluctuations Q of a Brownian particle trapped in a stationary harmonic well. We find that P(Q, t) can be expressed in terms of a modified Bessel function of zeroth order that in the limit t > infinity exactly recovers the heat distribution function obtained recently by Imparato et al. Phys. Rev. E 76, 050101(R) (2007)] from the approximate solution to a Fokker-Planck equation. This long-time result is in very good agreement with experimental measurements carried out by the same group on the heat effects produced by single micron-sized polystyrene beads in a stationary optical trap. An earlier exact calculation of the heat distribution function of a trapped particle moving at a constant speed v was carried out by van Zon and Cohen Phys. Rev. E 69, 056121 (2004)]; however, this calculation does not provide an expression for P(Q, t) itself, but only its Fourier transform (which cannot be analytically inverted), nor can it be used to obtain P(Q, t) for the case v=0.
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In the first decade of the 21st century, national notables were a significant theme in the Finnish theatre. The lives of artists, in particular, inspired the performances that combined historical and fictional elements. In this study, I focus on the characters of female artists in 18 Finnish plays or performances from the first decade of the 21st century. The study pertains to the field of performance analysis. I approach the characters from three points of view. Firstly, I examine them through the action of performances at the thematic level. Secondly, I concentrate on the forms of relationships between the audience and the half-historical character. Thirdly, I examine the representations of characters and their relationships to the audience using myth as a tool. I approach characters from the frame of feminist phenomenological theatre study but also combine the points of view of other traditions. As a model, I adapt the approach of the theatre researcher Bert O. States, which concentrates on the relation between a play s text and an actor, and between an actor and the public. Furthermore, I use the analysing tools of performance art in an examination of performances counted among the contemporary performance genre. The biographical plays about these artists are concentrated in the domestic sphere and take part in the conversation about the position of women in both the community and private life. They represent the heroines work, love, temptations and hardships. The artists do not carry out heroic acts, being more like everyday heroines whose lives and art were shared with the audience in an aphoristic atmosphere. In the examined performances, criticism of the heterosexual matrix was mainly conservative and the myths of female and male artists differed from each other: the woman artist was presented as a super heroine whose strength often meant sacrifices; the male artist was a weaker figure primarily pursuing his individualistic objectives. The performances proved to be a kind of documentary theatre, a hybrid of truth and fiction. Nonetheless, the constructions of subject and identity mainly represented the characters of the mythical stories and only secondarily gave a faithful rendition of the artists lives. Although these performances were addressed to the general and heterogeneous public, their audience proved to be a strictly predefined group, for which the national myths and the experience of a collective identity emerged as an important theme. The heroine characters offered the audience "safe" idols who ensured the solidity of the community. These performances contained common, shared values and gave the audience an opportunity to feel empathy and to be charmed by the confessions of well-known national characters.
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Starting from readily available norbornenobenzoquinone 7 and employing a photothermal metathesis reaction as the main strategy, novel "roofed" polyquinane bisenones 3 and 13 have been synthesized. Among these, the former is potentially serviceable for further elaboration to dodecahedrane 1. Catalytic hydrogenation of 3 provided the dione 12, which fully inscribes the circumference of dodecahedrane sphere. The "roofed" C-16-bisenone 3 has been successfully annulated to C19-bisenone 24 and C19-trisenone 26 by employing the Greene methodology and Pauson-Khand reaction, respectively. The molecular structures of 3 and 13 were computed using molecular mechanics and semiempirical MO methods. The nonbonded distances between the double bonds vary strongly with the method employed. The interactions between the pi-MO's were, therefore, probed by means of photoelectron (PE) spectroscopy. Comparison with the PE spectra of a series of model systems with increasing complexity enabled an unambiguous assignment of the observed peaks. The symmetric and antisymmetric combinations of the pi-MO's of the enone moieties of 3 and 13 show large splittings, characteristic of propano-bridged systems in which through-space and through-bond effects act in concert.
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A polymeric sorbent containing triphenylphosphinimine residues has been obtained from crosslinked chloromethylated polystyrene by azidation, using phase-transfer catalysis, followed by reaction with triphenylphosphine at room temperature. The sorbent exhibits 100 % sorption selectivity for Fe(III) in the presence of Cu(II), Fe(II), Ni(II), Co(II), Mn(II), and Zn(II) in aqueous media. In the absence of Fe(III), however, Fe(II) is selectively sorbed over the other metal ions, and in the absence of both Fe(II) and Fe(III), Cu(II) has the highest selectivity of sorption on the resin. The sorption of Fe(III) is sensitive to pH, being maximum at pH not, vert, similar 2 and falling sharply at both higher and lower pH values. The sorbed Fe(III) is easily stripped with dilute HCl and the resulting protonated resin is regenerated to its original sorption capacity by treatment with dilute NaOH at room temperature.
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Transition metal oxides like Fe2O3, Ni2O3, Co2O3 and MnO2 suppress the combustion of polystyrene. The effect has been explained on the basis of condensed-phase and gas-phase reactions.
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Equations for solid-state decompositions which are controlled by the phase-boundary movement and nucleation have been examined using ammonium perchlorate/polystyrene propellant decomposition at 503 K and 533 K. It was found that 3 different equations governed by the nucleation process show a good fit of data at these temperatures. However, the best fit was obtained for the following Avrami-Erofeev equation, [-In (1 - α]1/4=kt.
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Nanocrystalline Fe53Co47 alloy was synthesized by a single-step transmetallation chemical method at room temperature. The Fe53Co47 alloy nanoparticles of 77 and 47 wt% were dispersed in silica matrix by the sol-gel process using tetraethyl orthosilcate. Structural studies reveal that the as-prepared alloy powders are in bcc phase and silica is in an amorphous state. The phase-transition temperature and Mossbauer spectra analysis of the Fe-Co alloy establishes the homogeneous alloy formation. A saturation magnetization of 218 emu/g was obtained for pure FeCo alloy at room temperature. Scanning electron microscopic analysis demonstrates the hollow-sphere morphology for FeCo alloy particles. Magnetic nanocomposite consisting of 47 wt% FeCo-silica shows enhanced thermal stability over the native FeCo alloy. Electrical and dielectric properties of 47 wt% FeCo-silica nanocomposites were investigated as a function of frequency and temperature. It was found that the dielectric constants and dielectric loss were stable throughout the measured temperature (310-373 K). Our results indicate that FeCo-silica nanocomposite is a promising candidate for high-frequency applications. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Hantaviruses are one of the five genera of the vector-borne virus family Bunyaviridae. While other members of the family are transmitted via arthropods, hantaviruses are carried and transmitted by rodents and insectivores. Occasional transmission to humans occurs via inhalation of aerosolized rodent excreta. When transmitted to man hantaviruses cause hemorrhagic fever with renal syndrome (HFRS, in Eurasia, mortality ~10%) and hantavirus cardiopulmonary syndrome (HCPS, in the Americas, mortality ~40%). The single-stranded, negative-sense RNA genome of hantaviruses is in segments S, M and L that respectively encode for nucleocapsid (N), glycoproteins Gn and Gc, and RNA-dependent RNA-polymerase (RdRp or L protein). The genome segments, encapsidated by N protein to form ribonucleoprotein (RNP), are enclosed inside a lipid envelope decorated by spikes formed of Gn and Gc. The focus of this study was to understand the mechanisms and interactions through which the virion is formed and maintained. We observed that when extracted from virions both Gn and Gc favor homo- over hetero-oligomerization. The minimal glycoprotein complexes extracted from virion by detergent were observed, by using ultracentrifugation and gel filtration, to be tetrameric Gn and homodimeric Gc. These results led us to suggest a model where tetrameric Gn complexes are interconnected through homodimeric Gc units to form the grid-like surface architecture described for hantaviruses. This model was found to correlate with the three-dimensional (3D) reconstruction of virion surface created using cryo-electron tomography (cryo-ET). The 3D-density map showed the spike complex formed of Gn and Gc to be 10 nm high and to display a four-fold symmetry with dimensions of 15 nm times 15 nm. This unique square-shaped complex on a roughly round virion creates a hitch for the assembly, since a sphere cannot be broken into rectangles. Thus additional interactions are likely required for the virion assembly. In cryo-ET we observed that the RNP makes occasional contacts to the viral membrane, suggesting an interaction between the spike and RNP. We were able to demonstrate this interaction using various techniques, and showed that both Gn and Gc contribute to the interaction. This led us to suggest that in addition to the interactions between Gn and Gc, also the interaction between spike and RNP is required for assembly. We found galectin-3 binding protein (referred to as 90K) to co-purify with the virions and showed an interaction between 90K and the virion. Analysis of plasma samples taken from patients hospitalized for Puumala virus infection showed increased concentrations of 90K in the acute phase and the increased 90K level was found to correlate with several parameters that reflect the severity of acute HFRS. The results of these studies confirmed, but also challenged some of the dogmas on the structure and assembly of hantaviruses. We confirmed that Gn and RNP do interact, as long assumed. On the other hand we demonstrated that the glycoproteins Gn and Gc exist as homo-oligomers or appear in large hetero-oligomeric complexes, rather than form primarily heterodimers as was previously assumed. This work provided new insight into the structure and assembly of hantaviruses.
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We present a low-complexity algorithm based on reactive tabu search (RTS) for near maximum likelihood (ML) detection in large-MIMO systems. The conventional RTS algorithm achieves near-ML performance for 4-QAM in large-MIMO systems. But its performance for higher-order QAM is far from ML performance. Here, we propose a random-restart RTS (R3TS) algorithm which achieves significantly better bit error rate (BER) performance compared to that of the conventional RTS algorithm in higher-order QAM. The key idea is to run multiple tabu searches, each search starting with a random initial vector and choosing the best among the resulting solution vectors. A criterion to limit the number of searches is also proposed. Computer simulations show that the R3TS algorithm achieves almost the ML performance in 16 x 16 V-BLAST MIMO system with 16-QAM and 64-QAM at significantly less complexities than the sphere decoder. Also, in a 32 x 32 V-BLAST MIMO system, the R3TS performs close to ML lower bound within 1.6 dB for 16-QAM (128 bps/Hz), and within 2.4 dB for 64-QAM (192 bps/Hz) at 10(-3) BER.
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A novel universal approach to understand the self-deflagration in solids has been attempted by using basic thermodynamic equation of partial differentiation, where burning mte depends on the initial temperature and pressure of the system. Self-deflagrating solids are rare and are reported only in few compounds like ammonium perchlorate (AP), polystyrene peroxide and tetrazole. This approach has led us to understand the unique characteristics of AP, viz. the existence of low pressure deflagration limit (LPL 20 atm), hitherto not understood sufficiently. This analysis infers that the overall surface activation energy comprises of two components governed by the condensed phase and gas phase processes. The most attractive feature of the model is the identification of a new subcritical regime I' below LPL where AP does not burn. The model is aptly supported by the thermochemical computations and temperature-profile analyses of the combustion train. The thermodynamic model is further corroborated from the kinetic analysis of the high pressure (1-30 atm) DTA thermograms which affords distinct empirical decomposition rate laws in regimes I' and 1 (20-60 atm). Using Fourier-Kirchoff one dimensional heat transfer differential equation, the phase transition thickness and the melt-layer thickness have been computed which conform to the experimental data.
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Right as an Argument. Leo Mechelin and the Finnish Question 1886-1912 At the turn of the 20th century the Finnish Question rose up as a political and juridical issue at the international arena. The vaguely précised position of Finland in the Russian empire led to diverse conclusions concerning the correctness of the February manifesto of 1899. It was predominantly among a European elite of politicians, cultural workers and academics the issue rose some interest. Finns were active making propaganda for their cause, and they put an emphasis on the claim that the right was on the Finnish side. In the study Elisabeth Stubb compare the Finnish, Russian and European statements about the Finnish Question and analyse their use of right as an argument. The Finnish Question offers at the same time a case study of a national entity which possesses a political sphere of life but is not fully independent, and its possibilities to drive its interests in an international context. Leo Mechelin (1839-1914), the leader of the Finnish propaganda organization abroad, is used as a point of departure. The biographical stance is formed into a triangle, where Leo Mechelin, the idea of right and the Finnish Question abroad are the three cornerstones. The treatment of one cornerstone sheds a ligth on the two others. The metaphor of triangulation also worked as a method to reach "a third stance" in a scinetific and political issue that usually is polarised into two opposite alternatives. An adherence to a strict legal right could not in the end offer a complete, unquestionable and satisfactory solution to the Finnsih Question, it was dependent on "the right of state wisdom and sound insight". The Finnish propaganda abroad used almost completely alternative ways of making politics. The propaganda did not have a decisive effect on countries' official politics, but gained unofficial support, especially in the public opinion and in academic statements. Mechelin claimed that the political field was dependent on public opinion and scientific research. Together with the official politics these two fields formed a triangle that shared the task of balancing the political arena and preventing it from making unwise decisions of taking an unjust turn. The international sphere worked as a balancing part in the Finnish Question. Mechelin tried by claiming the status of state for Finland's part to secure the country a place at the official international arena. At the same time, and especially when the claim was not fully adopted, he emphasised, and in a European context worked for, that right would become the guiding light not only for international relations, but also for the policy making in the inner life of the state.
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Trafficking in human beings has become one of the most talked about criminal concerns of the 21st century. But this is not all that it has become. Trafficking has also been declared as one of the most pressing human rights issues of our time. In this sense, it has become a part of the expansion of the human rights phenomenon. Although it is easy to see that the crime of trafficking violates several of the human rights of its victims, it is still, in its essence, a fairly conventional although particularly heinous and often transnational crime, consisting of acts between private actors, and lacking, therefore, the vertical effect associated traditionally with human rights violations. This thesis asks, then, why, and how, has the anti-trafficking campaign been translated in human rights language. And even more fundamentally: in light of the critical, theoretical studies surrounding the expansion of the human rights phenomenon, especially that of Costas Douzinas, who has declared that we have come to the end of human rights as a consequence of the expansion and bureaucratization of the phenomenon, can human rights actually bring salvation to the victims of trafficking? The thesis demonstrates that the translation process of the anti-trafficking campaign into human rights language has been a complicated process involving various actors, including scholars, feminist NGOs, local activists and global human rights NGOs. It has also been driven by a complicated web of interests, the most prevalent one the sincere will to help the victims having become entangled with other aims, such as political, economical, and structural goals. As a consequence of its fragmented background, the human rights approach to trafficking seeks still its final form, consisting of several different claims. After an assessment of these claims from a legal perspective, this thesis concludes that the approach is most relevant regarding the mistreatment of victims of trafficking in the hands of state authorities. It seems to be quite common that authorities have trouble identifying the victims of trafficking, which means that the rights granted to themin international and national documents are not realized in practice, but victims of trafficking are systematically deported as illegal immigrants. It is argued that in order to understand the measures of the authorities, and to assess the usefulness of human rights, it is necessary to adopt a Foucauldian perspective and to observe the measures as biopolitical defence mechanisms. From a biopolitical perspective, the victims of trafficking can be seen as a threat to the population a threat that must be eliminated either by assimilating them to the main population with the help of disciplinary techniques, or by excluding them completely from the society. This biopolitical aim is accomplished through an impenetrable net of seemingly insignificant practices and discourses that not even the participants are aware of. As a result of these practices and discourses, trafficking victims only very few of fit the myth of the perfect victim, produced by biopolitical discourses become invisible and therefore subject to deportation as (risky) illegal immigrants, turning them into bare life in the Agambenian sense, represented by the homo sacer, who cannot be sacrificed, yet does not enjoy the protection of the society and its laws. It is argued, following Jacques Rancière and Slavoj i ek, that human rights can, through their universality and formal equality, provide bare life the tools to formulate political claims and therefore utilize their politicization through their exclusion to return to the sphere of power and politics. Even though human rights have inevitably become entangled with biopolitical practices, they are still perhaps the most efficient way to challenge biopower. Human rights have not, therefore, become useless for the victims of trafficking, but they must be conceived as a universal tool to formulate political claims and challenge power .In the case of trafficking this means that human rights must be utilized to constantly renegotiate the borders of the problematic concept of victim of trafficking created by international instruments, policies and discourses, including those that are sincerely aimed to provide help for the victims.
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The reaction of [Cu2(O2CMe)4(H2O)2] with N, N, N′, N′-tetramethylethane- 1,2-diamine (tmen) in ethanol yielded the dicopper(II) complex [Cu2(OH)(O2CMe)(tmen)2][ClO4]21. A similar reaction with N, N- dimethylethane- 1,2-diamine (dmen) afforded a crystalline product 2 in which two dicopper(II) complexes, [Cu2(OH)(O2CMe)(dmen)2][ClO4]22a and [Cu2(OH)(O2CMe)(H2O)2(dmen)2][ClO4]22b, are cocrystallized in a 1 : 1 molar ratio along with 2NaClO4. The crystal structures of 1 and 2 have been determined. The complexes have an asymmetrically dibridged [Cu2(µ-OH)(µ-O2CMe)]2+ core. The co-ordination geometry of the metal is square planar (CuO2N2). The copper atoms in 2b have a square-pyramidal CuO3N2 co-ordination sphere. The Cu Cu distances and Cu–O–Cu angles in 1, 2a and 2b are 3.339(2), 3.368(3), 3.395(7)Å, 120.1(2), 116.4(1) and 123.6(2)°, respectively. Complex 1 exhibits an axial ESR spectrum in a methanol glass giving g∥= 2.26 (A∥= 164 × 10–4 cm–1) and g⊥= 2.04. The ESR spectra obtained from the bulk material of the dmen product are indicative of the presence of two dimers, viz. complex 2a(g∥= 2.25, A∥= 165 × 10–4 cm–1; g⊥= 2.03) and 2b(g∥= 2.19, A∥= 184 × 10–4 cm–1; g⊥= 2.0). Variable-temperature magnetic susceptibility measurements on these complexes show an intramolecular antiferromagnetic coupling in the dimeric core. The fitting parameters are J=–27.8 cm–1, g= 2.1 for complex 1 and J=–10.1 cm–1, g= 2.0 for 2. The magnetostructural properties of the complexes are discussed. There is a linear correlation of the –2J values with the Cu Cu distances among dibridged complexes having square-planar copper(II) centres.
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The main purpose of this study was to provide a full account of the Christian social work carried out at the Tampere City Mission (TCM) as well as the Missions sphere of operations from the Second World War to the early 1970s, comprising a period of significant change. The study consists of charting the processes of change and connections within the activities of the TCM and how examining these were linked to the general tendencies of the period, in lay work, social work, professionalization and the representation of gender. The positioning of the activities is described on the basis of these tendencies. The main sources for the study were the archives of the Mission, for example the minutes of meetings, correspondences as well as annual reports, and the archives of its partners, such as the City of Tampere, the Evangelical Lutheran parishes of Tampere and the State Welfare Administration. The archives of the Helsinki, Turku and Stockholm Missions supplied comparison reference and other material. In particular, social welfare and Christian social work technical journals of were used as printed sources. The principal method used was the genetic method of historiology. The research subject was also evaluated from the point of view of third sector research in addition to that of professionalization studies and gender studies. By the beginning of the research period, the TCM had turned more and more dedicatedly into a multipurpose social service organization maintaining social services such as old people s homes and children´s homes. This development continued, even though new areas of activity emerged and older ones fell into disuse. Social innovations sprang up, marriage counseling being one of them. On the national level, the TCM pioneered the provision of sheltered industrial work for intellectually disabled persons as well as housing services for them. As new activities were initiated, they overlapped with the established ones, and the TCM handed some of its child protection functions over to the municipality, in accordance with the current adaptation theory. The use of its own property to produce ever-changing social services may be the reason why the association s work continued on with vitality. Functional networks and political aid in the field of social services also bolstered the association. As in other Nordic countries, nonprofit organizations served as partners rather than competitors, with the State establishing institutional welfare arrangements. In the 1960s the municipal takeover of social services impacted the TCM activities. Rules for government subsidies and municipal allowances were not well established; hence these funds were not easily available, making improvements difficult. The TCM was a community in which women had a relatively strong position and an opportunity to make a difference. Female staff were reasonably equal to men, and women worked as heads of a several institutions. Care work employed a number of men, which went against the traditional segregation of labour between the sexes. The TCM s operations were from early on very professionalized, and were developed with particular care. Keywords: Christian social work, third sector, professionalization, gender
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Small angle X-ray scattering (SAXS) studies of poly2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) with varying conjugation, and polyethylene dioxythiophene complexed with polystyrene sulfonate (PEDOT-PSS) in different solvents have shown the importance of the role of pi-electron conjugation and solvent-chain interactions in controlling the chain conformation and assembly. In MEH-PPV, by increasing the extent of conjugation from 30 to 100%, the persistence length (l(p)) increases from 20 to 66 angstrom. Moreover, a pronounced second peak in the pair distribution function has been observed in the fully conjugated chain, at larger length scales. This feature indicates that the chain segments tend to self-assemble as the conjugation along the chain increases. In the case of PEDOT-PSS, the chains undergo solvent induced expansion and enhanced chain organization. The clusters formed by chains are better correlated in dimethyl sulfoxide (DMSO) solution than water, as observed in the scattered intensity profiles. The values of radius of gyration and the exponent (water: 2.6, DMSO: 2.31) of power-law decay, obtained from the unified scattering function (Beaucage) analysis, give evidence for chain expansion from compact (in water) to an extended coil in DMSO solutions, which is consistent with the Kratky plot analysis. The mechanism of this transition and the increase in dc conductivity of PEDOT-PSS in DMSO solution are discussed. The onset frequency for the increase in ac conduction, as well as its temperature dependence, probes the extent of the connectivity in the PEDOT-PSS system. The enhanced charge transport in PEDOT-PSS in DMSO is attributed to the extended chain conformation, as observed in the SAXS results.