Search results for "descriptive"
showing 10 items of 494 documents
Star-Shaped Conjugated Systems
2010
The present review deals with the preparation and the properties of star-shaped conjugated compounds. Three, four or six conjugated arms are attached to cross-conjugated cores, which consist of single atoms (B, C+, N), benzene or azine rings or polycyclic ring systems, as for example triphenylene or tristriazolotriazine. Many of these shape-persistent [n]star compounds tend to π-stacking and self-organization, and exhibit interesting properties in materials science: Linear and non-linear optics, electrical conductivity, electroluminescence, formation of liquid crystalline phases, etc.
Compatibilization of Polypropylene/Polyamide 6 Blend Fibers Using Photo-Oxidized Polypropylene.
2018
The use of polyamide/polyolefin blends has gained importance and concern for years, but they also show some issues to be adequately addressed, such as the incompatibility between the two components. This is usually overcome by using suitable compatibilizers, typically based on functionalized polyolefins. However, there is only little information about the use of a degraded polyolefins to induce compatibilization. This is even truer, as far as polyamide 6/polypropylene (PA6/PP) blends are concerned. In this work, compatibilization of PA6/PP blends by using small amounts of photo-oxidized PP was investigated
Reactive Powder Concrete Containing Basalt Fibers: Strength, Abrasion and Porosity
2020
The paper presents the test results of basalt fiber impact on a compressive and flexural strength, resistance to abrasion and porosity of Reactive Powder Concrete (RPC). The reasons for testing were interesting mechanical properties of basalt fibers, the significant tensile strength and flexural strength, and in particular the resistance to high temperatures, as well as a relatively small number of RPC tests performed with those fibers and different opinions regarding the impact of those fibers on concrete strength. The composition of the concrete mix was optimized to obtain the highest packing density of particles in the composite, based on the optimum particle size distribution curve acc.…
A Simple Metaheuristic for the FleetSize and Mix Problem with TimeWindows
2017
This paper presents a powerful new single-parameter metaheuristic to solve the Fleet Size and Mix Vehicle Routing Problem with Time Windows. The key idea of the new metaheuristic is to perform a random number of random-sized jumps in random order through four well-known local search operators. Computational testing on the 600 large-scale benchmarks of Bräysy et al. (Expert Syst Appl 36(4):8460–8475, 2009) show that the new metaheuristic outperforms previous best approaches, finding 533 new best-known solutions. Despite the significant number of random components, it is demonstrated that the variance of the results is rather low. Moreover, the suggested metaheuristic is shown to scale almost…
Spatial Besov regularity for stochastic partial differential equations on Lipschitz domains
2010
We use the scale of Besov spaces B^\alpha_{\tau,\tau}(O), \alpha>0, 1/\tau=\alpha/d+1/p, p fixed, to study the spatial regularity of the solutions of linear parabolic stochastic partial differential equations on bounded Lipschitz domains O\subset R^d. The Besov smoothness determines the order of convergence that can be achieved by nonlinear approximation schemes. The proofs are based on a combination of weighted Sobolev estimates and characterizations of Besov spaces by wavelet expansions.
MEASURING TEACHERS-AS-LEARNERS’ DIGITAL SKILLS AND READINESS TO STUDY ONLINE FOR SUCCESSFUL E-LEARNING EXPERIENCE
2019
INTRODUCTION
 We are living in the information society and digital competence is one of eight key competences for lifelong learning strategies (European Competence Framework); it is “both a requirement and right of citizens, if they are to be functional in today’s society” [1].
 The project “Competency based curriculum” is supported by the European Social Fund (ESF) and implemented by the National Centre for Education (NCE) of Latvia. E-learning course modules are to be developed and implemented for the professional development of all teachers in Latvia (pre-primary, primary, lower secondary and upper secondary school) [2]. These e-learning courses will be available as self-direc…
2019
IntroductionTeachers and student teachers in Germany are a high-risk population for stress and stress-related mental health problems. This often leads to early retirement in subsequent professional life. Various trials have demonstrated positive effects of stress prevention training on the perceived stress and stress-related symptoms of teachers. Although many studies show positive effects of mindfulness-based stress interventions, there is not yet any mindfulness-based intervention for teachers or student teachers in Germany. The aim of this trial is to evaluate a training that combines mindfulness-based and cognitive interventions into one programme, addressing to the specific burdens of …
Meta model of e-learning materials development
2014
The multitude of software tools is available for the creation of learning resources. However the majority of these tools provided by different software producers do not have a unified mechanism by means of which it would be possible to search and reuse the existing learning resources or their elements. To solve this problem the structures of descriptive data can be used. The aim of this paper is to describe a meta-model of e-learning objects and e-learning formats that could be used in the creation of e-learning materials compatible with various e-learning standards. The meta-data models that are used in widely-known learning resourcesâ repositories and their structureâs metadata standa…
Descriptive epidemiology of nasal carriage of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus among patients admitted to two he…
2014
Aim: To evaluate nasal carriage rate and variables associated with Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) in patients admitted in two healthcare facilities. Results: S. aureus was isolated from 159 (26%) of the enrolled patients. Methicillin-susceptible S. aureus was isolated from 150 (24.5%) patients, and MRSA was isolated from 9 (1.5%). Cancer and previous hospitalization were associated with a significantly higher frequency of nasal S. aureus carriage among the patients admitted to the general hospital and the nephrology department, respectively. MRSA isolates were heterogeneous with respect to their staphylococcal cassette chromosome mec element (SC…
Bioactivity of bioceramic materials used in the dentin-pulp complex therapy : a systematic review
2019
Este es el artículo que se ha publicado de forma definitiva en: https://www.mdpi.com/1996-1944/12/7/1015 Dentistry-applied bioceramic materials are ceramic materials that are categorized asbioinert, bioactive and biodegradable. They share a common characteristic of being specificallydesigned to fulfil their function; they are able to act as root canal sealers, cements, root repair or fillingmaterials. Bioactivity is only attributed to those materials which are capable of inducing a desiredtissue response from the host. The aim of this study is to present a systematic review of availableliterature investigating bioactivity of dentistry-applied bioceramic materials towards dental pulp stemcel…