Wyniki wyszukiwania - BazTech

1

Considering semi-crystallinity in molecular simulations of mechanical polymer properties : using nanoindentation of polyethylene as an example

Fritz Susanne

Computer Methods in Materials Science

|

2021

|

Vol. 21, No. 1

35--50

EN

Molecular dynamic (MD) simulations have been used to investigate the response of semi-crystalline polymers in nanoindentation tests, using polyethylene (PE) as an example. To that purpose, semi-crystalline simulation boxes of linear PE with various chain lengths up to C2000 were created by homogeneous nucleation during the non-isothermal cooling of melts. The final crystallinity depended on the chain length and the cooling rate used and could be estimated using various parameters like density, fraction of bonds in trans conformation, and energy terms. The simulation boxes were transferred into surface models and subjected to nanoindentation tests using non equilibrium MD. This allowed the deformation behaviour of the material to be analysed directly. Strong dependencies on the crystallinity of the PE were found, which underlines the importance of considering crystallinity when investigating the mechanical properties of semi-crystalline polymers by means of simulations.

2

Molecular order and dynamics of 5CB liquid crystals in confined space - computer simulation

Gwizdała W., Gburski Z.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

|

2015

|

Vol. 19, No 1

35--64

EN

We studied the dynamical and structural properties of an important nematic 4-n-pentyl-4’-cyanobiphenyl (5CB) mesogen placed near carbon allotropes (graphene, nanotube), using modeling and molecular dynamics simulations (MD). Every investigated nanosystem (a free cluster of 5CB, a 5CB cluster confined in a single-walled carbon nanotube, 5CB mesogens located between two graphene sheets, a 5CB thin layer on a single-walled carbon nanotube, a thin layer of a 5CB molecules near graphene plane) contains a liquid crystal cluster consisting of 5CB molecules (22–98 molecules). We also performed a computer experiment for a 5CB bulk sample (196 5CB mesogens) with periodic boundary conditions. The following observables were calculated for several temperatures: mean square displacement, radial distribution function and second rank order parameter of 5CB clusters. The obtained results from MD simulations were discussed and compared with the experimental data.

3

Growth of intermetallic compound between indium-based thermal interface material and copper substrate: molecular dynamics simulations

Fałat T., Płatek B.

Materials Science Poland

|

2015

|

Vol. 33, No. 2

445--450

EN

The diffusion phenomenon occurring between copper and indium was investigated by molecular dynamics simulations. The calculations were carried out in various temperatures in aging domain with the use of the commercially available Materials Studio v.6. software. The results showed that the intermetallic compound (IMC) growth followed the parabolic law, which indicated this growth to be mainly controlled by volume diffusion. The growth activation energy was estimated at 7.48 kJ.mol(-1).

4

Projekt funkcji skrótu bazującej na konstrukcji MCM i przekształceniach trójkątnych

Glet M.

Biuletyn Wojskowej Akademii Technicznej

|

2011

|

Vol. 60, nr 4

400-411

PL

Praca przedstawia autorskie podejście do problemu projektowania funkcji skrótu. Zaproponowana konstrukcja bazuje na schemacie Mix-Compress-Mix przekształceniach trójkątnych oraz multipermutacjach. Dzięki temu przedstawiona rodzina funkcji skrótu charakteryzuje się dobrymi własnościami kryptograficznymi oraz możliwością efektywnej implementacji w środowiskach wielowątkowych.

EN

This paper presents a new familly of cryptographic hash functions based on Mix-Compess-Mix schema multipermutation and T-functions. This new familly has very good cryptographic properties and can be impelmented in a very efective way in multithreaded environments.

5

The evolutionary heuristics applied to the analysis of multidimensional data

Jasińska-Suwada A.

Prace Naukowe Politechniki Warszawskiej. Elektronika

|

2006

|

z. 156

163-170

EN

This paper describes the pattern recognition system for analysis of multidimensional data, based on natural meta-heuristics. The system consists of tree modules: preprocessing, feature extraction and clustering. Feature extraction module is based on Molecular Dynamic (MD). In clustering are used two natural methods: Simulated Annealing (SA) and Taboo Search (TS). The system is used to analyze an evolving population of individuals equipped with 'genetic codes'. Clustering module extracts groups of data with similar genetic code named clusters and make of possible to observe their geographical localization. The feature extraction verifies the clustering and allows analyzing of clustering patterns, their shapes and the distances between them.

6

Sprawność termiczna modułów kapilarnych do destylacji membranowej

Gryta M.

Inżynieria Chemiczna i Procesowa

|

2006

|

T. 27, z. 1

305-314

PL

Badano efektywność wykorzystania ciepła w procesie destylacji membranowej w modułach kapilarnych o różnej konstrukcji. Sprawność termiczną określono jako stosunek ilości ciepła zużywanego na wytworzenie pary do całkowitej ilości ciepła wymienionej w module membranowym. Zbadano wpływ sposobu ułożenia membran w obudowie modułu oraz warunków jego eksploatacji (temperatura i natężenie przepływu strumieni) na wielkość ocenianego parametru.

EN

The influence of a capillary module design on the effectiveness of heat utilization in the membrane distillation (MD) process has been evaluated. Heat efficiency was defined as a ratio of the latent heat consumed in the evaporation to the total heat exchanged in the membrane module. The dependence of this parameter on the membrane arrangement within the MD capillary module and the working conditions (temperature and flow rates of streams) was investigated.