Interplay between solid state microstructure and photophysics for poly(9,9-dioctylfluorene) within oriented polyethylene hosts

We present a study of isotropic and uniaxially oriented binary blend films comprising ≤1 wt % of the conjugated polymer poly(9,9‐dioctylfluorene) (PFO) dispersed in both ultra‐high molecular weight (UHMW) and linear‐low‐density (LLD) polyethylene (PE). Polarized absorption, fluorescence and Raman spectroscopy, scanning electron microscopy, and X‐ray diffraction are used to characterize the samples before and after tensile deformation. Results show that blend films can be prepared with PFO chains adopting a combination of several distinct molecular conformations, namely glassy, crystalline, and the so‐called β‐phase, which directly influences the resulting optical properties. Both PFO concentration and drawing temperature strongly affect the alignment of PFO chains during the tensile drawing of the blend films. In both PE hosts, crystallization of PFO takes place during drawing; the resulting ordered chains show optimal optical anisotropy. Our results clarify the PFO microstructure in oriented blends with PE and the processing conditions required for achieving the maximal optical anisotropy.ISSN:0887-6266ISSN:0098-1273ISSN:1099-048

The influence of backbone fluorination on the dielectric constant of conjugated polythiophenes

The ability to modify or enhance the dielectric constant of semiconducting polymers can prove valuable for a range of optoelectronic and microelectronic applications. In the case of organic photovoltaics, increasing the dielectric constant of the active layer has often been suggested as a method to control charge generation, recombination dynamics, and ultimately, the power conversion efficiencies. In this contribution, the impact that the degree and pattern of fluorination has on the dielectric constant of poly(3-octylthiophene) (P3OT), a more soluble analogue of the widely studied conjugated material poly(3-hexylthiophene), is explored. P3OT and its backbone-fluorinated analogue, F-P3OT, are compared along with a block and alternating copolymer version of these materials. It is found that the dielectric constant of the polymer thin films increases as the degree of backbone fluorination increases, in a trend consistent with density functional theory calculations of the dipole moment

HUNGARIAN EXPERIENCE IN STRUCTURAL DESIGN CODING (HISTORICAL ANTECEDENTS OF EUROCODE-2)

This paper gives review of the historical antecedents of Eurocode-2 in Hungary and East Europe. The method of permissible stresses, using uniform safety factor was first changed in 1950 in Hungary by the semi-probabilistic method using partial safety factors. This new method was accepted with some resistance on the part of the leading structural engineers. Nevertheless most of the East-European countries accepted the new method with some political overtones', to be follow the Soviet example. The authors assert in the papaer that due to the economic necessities. Hungary and the other East European countries gained experience with the regulations affording less safety than the EC2, and this offers an interesting set of experience to the West European countries which have intoduced or are introducing the semi-probabilistic procedure. The most significant point all the experience is the recognition that only one part of the parameters in the structural analysis determining safety can be handled statistically. During design the statistically not significant data such as the error of the structural model must also be taken into consideration. Based on the experience, the authors propose an alternative design method

The Way Cyber Physical Systems Will Revolutionise Maintenance

30th Conference on Condition Monitoring and Diagnostic Engineering Management (COMADEM 2017). 10 to 13, Jul, 2017. Preston, United Kingdom.The way maintenance is carried out is altering rapidly. The introduction of Cyber Physical Systems (CPS) and cloud technologies are providing new technological possibilities that change dramatically the way it is possible to follow production machinery and the necessity to carry out maintenance. In the near future, the number of machines that can be followed from remoteness will explode. At the same time, it will be conceivable to carry out local diagnosis and prognosis that support the adaptation of Condition Based Maintenance (CBM) i.e. financial optimisation can drive the decision whether a machine needs maintenance or not. Further to this, the cloud technology allows to accumulate relevant data from numerous sources that can be used for further improvement of the maintenance practices. The paper goes through the new technologies that have been mentioned above and how they can be benefitted from in practise.info:eu-repo/semantics/publishedVersio

O ser-autor: deslocamentos entre a escrita científica e a escritura de si ( The being-author: shifts between scientific writing and self-writing)

Este artigo propõe uma reflexão, sustentada na teoria da Análise de Discurso, sobre a escrita científica e o seu imaginário de objetividade, a fim de pensar se há um espaço para o singular do pesquisador-autor na produção científica. A partir disso, discute-se a possibilidade de tomar a escrita científica como uma escritura de si, mostrando os elementos que estão em jogo no processo de escritura e suas relações com a subjetividade e com a constituição do ser-autor.PALAVRAS-CHAVE: Escrita Científica. Escrita de Si. Autoria. Análise de Discurso. ABSTRACT This article proposes a reflection, sustained on the theory of Discourse Analysis, on scientific writing and its objectivity imaginary in order to think if there is a space for the singularity of the researcher-author in scientific production. From this, we discuss the possibility of taking scientific writing as self-writing, showing the elements that are at play in the writing process and its relation to subjectivity and to the constitution of the being-author.KEYWORDS: Scientific Writing. Self-Writing. Authorship. Discourse Analysis.This article proposes a reflection, sustained on the theory of Discourse Analysis, on scientific writing and its objectivity imaginary in order to think if there is a space for the singularity of the researcher-author in scientific production. From this, we discuss the possibility of taking scientific writing as self-writing, showing the elements that are at play in the writing process and its relation to subjectivity and to the constitution of the being-author.KEYWORDS: Scientific Writing. Self-Writing. Authorship. Discourse Analysis

Finger posture modulates structural body representations

Patients with lesions of the left posterior parietal cortex commonly fail in identifying their fingers, a condition known as finger agnosia, yet are relatively unimpaired in sensation and skilled action. Such dissociations have traditionally been interpreted as evidence that structural body representations (BSR), such as the body structural description, are distinct from sensorimotor representations, such as the body schema. We investigated whether performance on tasks commonly used to assess finger agnosia is modulated by changes in hand posture. We used the ‘in between’ test in which participants estimate the number of unstimulated fingers between two touched fingers or a localization task in which participants judge which two fingers were stimulated. Across blocks, the fingers were placed in three levels of splay. Judged finger numerosity was analysed, in Exp. 1 by direct report and in Exp. 2 as the actual number of fingers between the fingers named. In both experiments, judgments were greater when non-adjacent stimulated fingers were positioned far apart compared to when they were close together or touching, whereas judgements were unaltered when adjacent fingers were stimulated. This demonstrates that BSRs are not fixed, but are modulated by the real-time physical distances between body parts

Solution-crystallization and related phenomena in 9,9-dialkyl-fluorene polymers. I. Crystalline polymer-solvent compound formation for poly(9,9-dioctylfluorene)

Polymer-solvent compound formation, occurring via co-crystallization of polymer chains and selected small-molecular species, is demonstrated for the conjugated polymer poly(9,9-dioctylfluorene) (PFO) and a range of organic solvents. The resulting crystallization and gelation processes in PFO solutions are studied by differential scanning calorimetry, with X-ray diffraction providing additional information on the resulting microstructure. It is shown that PFO-solvent compounds comprise an ultra-regular molecular-level arrangement of the semiconducting polymer host and small-molecular solvent guest. Crystals form following adoption of the planar-zigzag β-phase chain conformation, which, due to its geometry, creates periodic cavities that accommodate the ordered inclusion of solvent molecules of matching volume. The findings are formalized in terms of nonequilibrium temperature–composition phase diagrams. The potential applications of these compounds and the new functionalities that they might enable are also discussed. © 2015 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 1481–149

Serum levels of s-100B after recreational scuba diving

Recreational scuba diving is a sport of increasing popularity. Previous studies indicating subtle brain injury in asymptomatic divers imply a cumulative effect of minor neural insults in association with diving for professional and/or recreational purposes, over the long-term. This is the first study to investigate putative neural tissue burden during recreational scuba diving by measuring circulating levels of S-100B, a sensitive biomarker of brain injury. 5 male divers performed 3 consecutive dives under conservative recreational diving settings (maximum depth 15m, duration of dive 56min, ascend rate 1.15m/min) with an interval of 12h between each session. Although a small increase in serum S-100B levels after each dive was apparent, this increase did not quite reach statistical significance (p=0.057). Moreover, no abnormal S-100B values were recorded (mean baseline: 0.06μg/L, mean post-dive: 0.086μg/L) and no effect of the 3 consecutive dives on changes in S-100B levels was detected. These results suggest that under the experimental conditions tested, diving does not seem to have a discernible and/or cumulative impact on central nervous system integrity. The extent to which variable diving settings and practices as well as individual susceptibility factors underlie putative neural tissue burden in asymptomatic divers, remains to be established. © 2011 Georg Thieme Verlag KG Stuttgart. New York