Scaling of Star Polymers with one to 80 Arms

We present large statistics simulations of 3-dimensional star polymers with up to $f=80$ arms, and with up to 4000 monomers per arm for small values of $f$. They were done for the Domb-Joyce model on the simple cubic lattice. This is a model with soft core exclusion which allows multiple occupancy of sites but punishes each same-site pair of monomers with a Boltzmann factor $v<1$. We use this to allow all arms to be attached at the central site, and we use the `magic' value $v=0.6$ to minimize corrections to scaling. The simulations are made with a very efficient chain growth algorithm with resampling, PERM, modified to allow simultaneous growth of all arms. This allows us to measure not only the swelling (as observed from the center-to-end distances), but also the partition sum. The latter gives very precise estimates of the critical exponents $\gamma_f$. For completeness we made also extensive simulations of linear (unbranched) polymers which give the best estimates for the exponent $\gamma$.Comment: 7 pages, 7 figure

Co‐designing the Cabriotraining : a training for transdisciplinary teams

Accessible summary The research was conducted by a team of researchers. Some of the researchers have experience of living with a disability. The researchers created training for other research teams that include experts by experience. The training has six parts. To decide what happened in the training, the researchers read articles and asked the research teams they trained about what problems they had and what they wanted to know about. The article tells why and how the training was made. It also says what training is needed for researchers with and without disabilities to learn and work together in a way that feels safe and useful. In developing and providing the training, it was very crucial to search for a safe and welcome space for all people involved (Figure 8). As we don't know what is "safe" for the other, this means we have to search together, in respect and with enough time to get to know each other. Background Researchers collected questions and needs for training from 10 inclusive research projects in the Netherlands. Based on literature research and the information collected, six training modules were developed. Researchers sought to learn how to develop and provide training and coaching to inclusive teams on organising collaboration in the different stages of their research projects. Method An iterative training development process to support inclusive research projects was initiated by a research duo backed by a transdisciplinary team including researchers, trainers and designers. Some members of the team have experiential knowledge based on living with a disability. Results Literature research resulted in four guiding theories, including Universal Design for Learning, Derrida's concept of Hospitality, post-materialist theory looking at agency as an assemblage, and Romiszowski's model situated within Instructional Design theory. Insights gained during development of the training modules are documented with text, figures and vignettes. A core finding was the need to add "Level Zero" to Romiszowski's model: a collective term created for all the interacting issues trainers had to consider because of research group diversity. Conclusions Hospitality formed the heart of "Level Zero." Creating a failure-free space for learning is an important pre-condition for the development and organisation of training. Training can inspire exploration and reflection on collaboration and can illuminate how to conduct research within transdisciplinary teams. Essential practices included working with nonverbal research methods, as these are (more) fit for purpose when including the knowledge of experts by experience and incorporating practice- and stakeholder-based knowledge

Psicología Y educación a distancia : una revisión de la literatura

O presente estudo investigou as contribuições da Psicologia para a educação a distância – EAD. Para isso, realizou-se revisão bibliográfica de publicações nacionais, entre 1999 e 2009, nas bases de dados SciELO, Lilacs, PsycINFO, BVS e Google Acadêmico. Foram selecionados 69 estudos, dos quais se excluíram 15, por não serem compatíveis com a pesquisa. Os resultados evidenciaram nove eixos temáticos: (1) tecnologia educacional a distância com fundamentos psicológicos, (2) afeição, (3) papel do tutor/professor, (4) teorias psicológicas, (5) interatividade, (6) evasão, (7) relatos de experiências, (8) avaliação de treinamento, desenvolvimento e educação a distância e (9) outros. Os temas tecnologia educacional a distância com fundamentos psicológicos e afeição obtiveram maior frequência nas publicações. Neste estudo, registrou-se, também, que, embora em ascensão desde 2006, os anos de maiores publicações da Psicologia na educação a distância foram 2008 e 2009. Sugere-se que estudos futuros ampliem esta pesquisa para incluir bases de dados internacionais.This study investigated the contributions of Psychology to Distance Learning. A literature review of national publications between 1999 to 2009 was made in the electronic databases SciELO, LILACS, PsycINFO, BVS and Google Scholar. From the 69 studies selected, 15 were excluded because they were not compatible with the research. The results showed nine themes: (1) the distance learning technology with psychological grounding, (2) affection, (3)the role of the tutor/professor, (4) psychological theories, (5) interactivity, (6) dropout, (7) reports of experiences, (8) assessment of distance training, development and education and (9) others. The topics distance education technology with psychological grounding and affection had a larger frequency in the publications. Since 2006, there was an increasing number of publications in psychology distance education, but the years of major publications were from 2008 to 2009. It is suggested that future studies expand this research including international databases.El presente estudio investigó las contribuciones de la Psicología para la Educación a Distancia – EAD. Para eso, fue realizada una revisión bibliográfica de publicaciones nacionales, entre 1999 y 2009 en las bases de datos SciELO, Lilacs, PsycINFO, BVS y Google Académico. Fueron seleccionados 69 estudios, de los cuales se excluyeron 15, por no ser compatibles con la pesquisa. Los resultados evidenciaron nueve ejes temáticos (1) tecnología educacional la distancia con fundamentos psicológicos; (2) afección; (3) papel del tutor/profesor; (4) teorías psicológicas; (5) interactividad; (6) evasión; (7) relatos de experiencias, (8) evaluación de entrenamiento, desarrollo y educación distancia y (9) otros. Los temas tecnología educacional a distancia con fundamentos psicológicos y afección obtuvieron mayor frecuencia en las publicaciones. En ese estudio se registró, también, que, aunque en ascensión desde 2006, los años de mayores publicaciones de la psicología en la educación a distancia, fueron 2008 y 2009. Se sugiere que estudios futuros amplíen esa pesquisa para incluir bases de datos internacionales

Performance improvement of silicon solar cells by nanoporous silicon coating

In the present paper the method is shown to improve the photovoltaic parameters of screenprinted silicon solar cells by nanoporous silicon film formation on the frontal surface of the cell using the electrochemical etching. The possible mechanisms responsible for observed improvement of silicon solar cell performance are discussed.Исследовано улучшение фотоэлектрических параметров кремниевых солнечных элементов, полученных методом трафаретной печати, за счет образования слоя пористого кремния на фронтальной поверхности элемента. Рассмотрены возможные механизмы, ответственные за улучшение производительности кремниевой солнечной ячейки.Досліджено поліпшення фотоелектричних параметрів кремнієвих сонячних елементів, отриманих методом трафаретного друку, за рахунок утворення шару пористого кремнію на фронтальній поверхні елемента. Розглянуто можливі механізми, відповідальні за поліпшення продуктивності кремнієвого сонячного елемента

Percolation in Systems Containing Ordered Elongated Objects

We studied the percolation and jamming of elongated objects using the Random Sequential Adsorption (RSA)technique. The objects were represented by linear sequences of beads forming needles. The positions of the beads wererestricted to vertices of two-dimensional square lattice. The external field that imposed ordering of the objects was introducedinto the model. The percolation and the jamming thresholds were determined for all systems under consideration.The influence of the chain length and the ordering on both thresholds was calculated and discussed. It was shown that fora strongly ordered system containing needles the ratio of percolation and jamming thresholds cp=cj is almost independenton the needle length d

New Multi-Bond Algorithm for Monte Carlo Simulation of Lattice Chains

The new algorithm for the Monte Carlo simulations of polymer lattice chains was developed. The model chains were constructed on a simple cubic lattice. The simulations were carried out on chains with and without excluded volume effect using the Metropolis scheme. The basic concept of the new algorithm is the multi-bond modification of the chain conformation instead of applying the classical set of elementary micromodifications. The correctness of the algorithm was verified by studying both static and dynamic properties of the chains. The new algorithm was found to be 3 to 8 times faster than the classical one

Monte Carlo Study of Chain Entanglements in Polymer Melt

The new multibond algorithm for the Monte Carlo simulations of polymers developed for an isolated chain was extended for the case of dense polymer melts. Polymer chains were confined to a simple cubic lattice with excluded volume and no attractive interactions (good solvent conditions). The simulations were carried out by the means of the classical Metropolis scheme. The algorithm was verified by the analysis of static and dynamic properties of polymer melts. The dependence of the longest relaxation time and the self-diffusion coefficient on the chain length and the polymer concentration was discussed and the proper scaling laws were formulated. The number of entanglements, their distribution, and lifetimes were determined for different chain lengths and melt concentrations using the new algorithm

Monte Carlo Study of Chain Entanglements in Polymer MeltDOI

The new multibond algorithm for the Monte Carlo simulations of polymers developed for an isolated chain was extended for the case of dense polymer melts. Polymer chains were confined to a simple cubic lattice with excluded volume and no attractive interactions (good solvent conditions). The simulations were carried out by the means of the classical Metropolis scheme. The algorithm was verified by the analysis of static and dynamic properties of polymer melts. The dependence of the longest relaxation time and the self-diffusion coefficient on the chain length and the polymer concentration was discussed and the proper scaling laws were formulated. The number of entanglements, their distribution, and lifetimes were determined for different chain lengths and melt concentrations using the new algorithm