Wyniki wyszukiwania - Biblioteka Nauki

1

Flora of vascular plants of Lake Smolak and the adjacent peatbog twenty years after the end of an experimental fertilisation

100%

Dziedzic J.

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tom 06

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nr 2

247-262

2

Quantum-Classical Calculations of the Nanomechanical Properties of Metals

100%

Dziedzic J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2009

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tom Vol. 13, No 3

207-310

EN

Molecular-dynamics (MD) simulations constitute an important tool in the study of nanoscale metallic systems, especially so in the face of the difficulties plaguing their experimental analysis. Main limitations of the MD method stem from the empirical nature of the potentials employed, their functional form which is postulated ad hoc, and its classical nature. The neglect of electronic effects and the unjustified utilization of the potential for system configurations significantly different from those, for which the potential was parametrized makes the results of strictly classical calculations dubious, at least for a certain class of systems. On the other hand, high computational complexity of quantum-based methods, where atomic interactions are described ab initio, prohibits their direct use in the study of systems larger than several tens of atoms. In the last decade, a growing popularity of so-called hybrid (or cross-scaling) methods can be observed, that is, methods which treat the most interesting part of the system with a quantum-based approach, while the remainder is treated classically. Physically sound handshaking between the two methodologies (quantum and classical) within a single simulation constitutes a serious challenge, the majority of difficulties concentrating around the interface between the fragments of the system treated with the two methods. The aforementioned interface is most easily constructed for covalently bonded systems, where the bonds cut by the isolation of the quantum-based region can be saturated by the introduction of specially crafted link-atoms. In metallic systems, however, due to electronic delocalization, this traditional approach cannot be employed. This paper describes a physically sound and adequately efficient computational technique, which allows for the inclusion of results of locally employed quantum-based computations within a molecular-dynamics simulation, for systems described by the many-body Sutton-Chen (SC) potential, used in the study of fcc metals. The proposed technique was developed taking as a point of departure the Learn-on-the-Fly (LOTF) formalism, a recent development itself. The original LOTF approach is only suitable for two- or three-body potentials and is serial in nature, whereas the proposed technique can be used with many-body potentials and is parallel-ready. An implementation of the proposed approach in the form of computer code, which allows for parallel hybrid computations for metallic systems is also described. Finally, results from a set of hybrid simulations of nanoindentation of a copper workmaterial with a hard indenter utilizing the aforementoned technique and computer code is presented, as evidence of its viability.

3

Obtaining ionic forces by the total-energy tight-binding method

100%

Dziedzic J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2007

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tom Vol. 11, No 3

285-294

EN

Applying a non-orthogonal tight-binding method to calculate ionic forces in a molecular-dynamics simulation vastly improves the transferability the model's transferability to different environments, compared with the tradi-tional empirical potential-driven molecular-dynamics. In this paper we present the details of computing derivatives of Hamiltonian and overlap matrix elements appearing in the Hellmann-Feynman expression for ionic forces in the NRL-TB model of tight-binding. The presented expressions are validated with the results obtained using a tight-binding-driven molecular-dynamics program.

4

Pojmowanie i organizacja ochrony przyrody w Polsce w XIX i na poczatku XX wieku

100%

Dziedzic J.

Humanistyka i Przyrodoznawstwo. Akademia Rolniczo-Techniczna w Olsztynie

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1997

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tom 03

161-175

5

I konferencja naukowa na temat `Jeziora lobeliowe - charakterystyka, funkcjonowanie i ochrona` [Poznan, Bytow, 13-16 IX 1993 r.]

100%

Dziedzic J.

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tom 40

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nr 2

115-117

6

Wysoka odporność korozyjna elektrolitycznych powłok stopowych ZnNi jako ważne kryterium zastosowania w zabezpieczeniu części drobnych w przemyśle maszynowym, energetycznym i budownictwie

63%

Dziedzic J. , Izydorczyk D.

Ochrona przed Korozją

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2015

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tom nr 10

362--365

PL

Obecnie obserwuje się wyraźny trend zastępowania powłok z czystego cynku na stali powłokami stopowymi cynku z metalami bardziej szlachetnymi (np. z niklem, kobaltem, molibdenem). W pracy przeanalizowano wpływ dodatku niklu w powłoce stopowej cynk-nikiel wytwarzanej galwanicznie. Powłoka stopowa cynk-nikiel wykazuje wyższy potencjał korozyjny, dzięki czemu uzyskuje się znaczące podwyższenie odporności korozyjnej oraz innych ważnych właściwości funkcjonalnych. Ogranicza się również emisję cynku do środowiska, co stanowi ważny aspekt ekologiczny. W pracy przedstawiono właściwości fizykochemiczne galwanicznych powłok stopowych cynk-nikiel otrzymywanych na drobnych wyrobach stalowych w procesie obróbki bębnowej w kąpieli alkalicznej. Zaprezentowano wyniki badań otrzymanych struktur powłok na podstawie zgładów metalograficznych. Opisano wyniki badań grubości i składu powłok metodą fluorescencji rentgenowskiej oraz testu w obojętnej mgle solnej wykonanych w laboratorium zakładowym. Przedstawione wyniki badań potwierdziły kilkukrotnie wyższą odporność korozyjną w odniesieniu do powłoki galwanicznej z czystego cynku nałożonej na stali.

EN

Today, there is a clear and strong trend to replace the pure zinc coatings, with more noble metals (eg. nickel, cobalt, molybdenum). This study analyzes the effects of introducing nickel to the galvanic zinc layer. Zinc-nickel alloy coating has a higher corrosion potential, thereby yielding a significant increase in corrosion resistance and other important functional properties. Application of zinc-nickel limits the emissions of zinc to environment – nowadays an especially important aspect. The study demonstrates the properties of the zinc-nickel coating applied on small steel parts in the alkaline process (barrel line). Results of the alloy layer structure examinations are discussed, based on the metallographic specimens. Coating thickness and composition studies have been performed using X-ray fluorescence and neutral salt spray test in company lab and are further discussed in this presentation.

7

Voice Command Recognition Using Hybrid Genetic Algorithm

63%

Wroniszewska M. , Dziedzic J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2010

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tom Vol. 14, No 4

377-396

EN

Speech recognition is a process of converting the acoustic signal into a set of words, whereas voice command recognition consists in the correct identification of voice commands, usually single words. Voice command recognition systems are widely used in the military, control systems, electronic devices, such as cellular phones, or by people with disabilities (e.g., for controlling a wheelchair or operating a computer system). This paper describes the construction of a model for a voice command recognition system based on the combination of genetic algorithms (GAs) and K-nearest neighbour classifier (KNN). The model consists of two parts. The first one concerns the creation of feature patterns from spoken words. This is done by means of the discrete Fourier transform and frequency analysis. The second part constitutes the essence of the model, namely the design of the supervised learning and classification system. The technique used for the classification task is based on the simplest classifier – K-nearest neighbour algorithm. GAs, which have been demonstrated as a good optimization and machine learning technique, are applied to the feature extraction process for the pattern vectors. The purpose and main interest of this work is to adapt such a hybrid approach to the task of voice command recognition, develop an implementation and to assess its performance. The complete model of the system was implemented in the C++ language, the implementation was subsequently used to determine the relevant parameters of the method and to improve the approach in order to obtain the desired accuracy. Different variants of GAs were surveyed in this project and the influence of particular operators was verified in terms of the classification success rate. The main finding from the performed numerical experiments indicates the necessity of using genetic algorithms for the learning process. In consequence, a highly accurate recognition system was obtained, providing 94.2% correctly classified patterns. The hybrid GA/KNN approach constituted a significant improvement over the simple KNN classifier. Moreover, the training time required for the GA to learn the given set of words was found to be on a level that is acceptable for the efficient functioning of the voice command recognition system.

8

Historyczne i wspolczesne stanowiska ramienic w jeziorach Pojezierza Olsztynskiego

63%

Hutorowicz A. , Dziedzic J.

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tom 05

279-291

9

Surface states on the real ZnTe and Zn₀.₇Mn₀.₃Te surface

63%

Kuźmiński S. , Dziedzic J.

Electron Technology

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1998

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tom Vol. 31, No. 3/4

351-353

EN

Surface photovolage spectroscopy (SPS) with stationary illumination and surface voltage barrier height measurements in function of temperature for the ZnTe and Zn₀.₇Mn₀.₃Te single crystals in the temperature range between 120 K and 270 K have been carried out. The contact potential difference has been determined between investigated sample surface and vibrating metal (gold) reference electrode. The measurements were performed in the clean vacuum of 10⁻⁶ Pa. Four groups of the surface states in the ZnTe, and additional one group of surface states connected with presence of Mn⁺² ions in Zn₀.₇Mn₀.₃Te have been found. The energy schemes for the investigated materials are presented.

10

Vascular plants of the Jar Brynicy Nature Reserve

63%

Jutrzenka-Trzebiatowski A. , Dziedzic J.

Natural Sciences. Olsztyn University of Agriculture and Technology

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1998

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nr 01

105-125

11

Vascular plants of the Jar Brynicy nature reserve

63%

Jutrzenka-Trzebiatowski A. , Dziedzic J.

Natural Sciences

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1998

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tom 01

12

Przykłady zastosowań oprogramowania Ansys Fluent w inżynierii środowiska

51%

Dziedzic J. , Kandefer S. , Kryzia D. , Olczak P.

Logistyka

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2015

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tom nr 4

8821--8831, CD3

PL

Oprogramowanie Ansys Fluent jest stosowane w różnych dziedzinach nauki i techniki. Przedstawiono przykładowe zastosowania tego programu w analizach związanych z mechaniką płynów i wymianą ciepła. Pierwszy przykład dotyczy ustalonego przepływu ciepła w solarnej rurze próżniowej typu Heat Pipe. Przy pomocy Solar Model (funkcja zastosowanego oprogramowania) określono wpływ budowy wnętrza na efektywność pozyskiwania energii słonecznej poprzez szacowanie strat do otoczenia. Drugi przykład dotyczy obliczeń cieplno-przepływowych solarnego zasobnika ciepłej wody użytkowej. Określono wpływ strat do otoczenia, ruchu płynu i zmian temperatury wokół wężownicy solarnej na przekazywanie ciepła z układu solarnego. Wykorzystano skrypty autorski skrypt (User Defined Function ) do obliczeń strat z powierzchni zewnętrznej do otoczenia, zmiany czasu przepływu czynnika oraz symulacji pracy pompy obiegowej, jako bezstratnego transportu ciepła bez uwzględnienia zagadnień mechanicznych.Trzeci przykład dotyczy szacowania strat cieplnych z rur instalacji ciepłej wody użytkowej w zależności od średnicy i grubości ścianki rury, grubości izolacji, temperatury wody, prędkości przepływu, temperatury otaczających pomieszczeń. Wykorzystując analizę parametryczną zbadano 720 wariantów obliczeniowych, przy założeniu umiejscowienia polipropylenowych rur wewnątrz budynku.

EN

Ansys Fluent software is used in various fields of science and technology. Publication present examples of use of this software in studies related to fluid mechanics and heat transfer. The first example concerns about steady heat flow in solar vacuum tube Heat Pipe. Solar Model helped to determine the effect of device interiors construction on the effectiveness of solar energy gain by estimating external losses. Second example concerns about thermal calculation of flow from solar panel to hot water tank. Heat losses to the environment were estimated by factors: fluid motion and temperature changes around the solar coil to transfer heat from the solar system. The last example relates to estimating heat loss from hot water installations. The analysis was conducted for complex variables such as diameter and its wall thickness, insulation thickness, liquid temperature, flow rate and ambient temperature of the surrounding. Using parametric analysis 720 cases were calculated.

13

Metodyka oceny uszkodzenia elementów konstrukcyjnych na przykładzie belki izotropowej jednostronnie utwierdzonej

51%

Samborski S. , Wieczorkiewicz J. , Rusinek R. , Dziedzic J.

Journal of Technology and Exploitation in Mechanical Engineering

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2015

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tom Vol. 1, nr 1-2

5--16

PL

W pracy zbudowano model numeryczny belki wspornikowej z uszkodzeniem i bez uszkodzenia oraz wyznaczono ichczęstości własne dla zadanych charakterystyk mate-riałowych. Następnie przeprowadzono badania na fizycznym obiekcie przy użyciu wibrometru laserowego PSV-500 firmy Polytec. Otrzymane rezultaty doświadczalne porównano z wynikami obliczeń nume-rycznych stosując metody analizy sygnału oparte na wykresach płaszczyzny fazowej.

EN

This paper focuses on analysis of damage detection cantilever beam. Finite Element Method was used to simulate vibrations of the intact and the damaged beams. Analysis of natural frequencies of both the intact and the damaged beams was performed in order to observe the effect of damage on the beams dynamics. Next, the phase diagrams technique was applied andfinally, experimental verification was performed to check the numerical results.

14

MD Simulations of Ultraprecision Machining of fcc Monocrystals

51%

Rychcik-Leyk M. , Białoskorski M. , Dziedzic J. , Rybicki J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2010

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tom Vol. 14, No 1-2

35-167

EN

In technical sciences, the term "machining" refers to the process of forming an object into a desired shape and size, with a desired quality of surface, by removing layers of its material by means of a cutting tool. The paper describes research on ultra-precision machining (UPM), where the abovementioned process takes place on the atomic level and involves systems (a machined object and a tool) several dozen nanometers in size. Three-dimensional computer simulations (virtual experiments) of UPM of monocrystalline copper with an infinitely hard tool were performed utilizing the classical molecular dynamics (MD) method with a many-body potential to describe the interatomic interactions. Among the examined issues were: the effect of the tool shape, machining speed and depth on the obtained workmaterial surfaces, and on the stresses, slip patterns and local temperature increases generated during the process.

15

Deposition methods of TiO₂ on the glass and characterisation of conductive layer in DSSC

51%

Dziedzic J. , Kwaśnicki P. , Marszałek L.

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2018

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tom Vol. 59, nr 9

6--8

EN

This work is dedicated to dye – sensitized solar cells (DSSC) with particular emphasis on the structure of photoanode with conductive TiO₂ layer, deposition methods of TiO₂, optical and morphological characteristics of obtained films. The test results of DSSC cells produced in the ML System Laboratory concerning the influence of the thickness of active layers on a number of parameters determining the efficient operation of the cell. Research conducted by many scientific communities around the world confirms that such cells have a big advantage over commonly used silicon cells. The main reason is the relatively low cost of materials and the lack of the need for advanced manufacturing technologies. In addition, the use of a wide range of colors and opportunity to control a transparency creates the possibility of using DSSC as an element integrated with the facade of the building.

PL

Praca poświęcona jest barwnikowym ogniwom słonecznym (DSSC) – ich strukturze, ze szczególnym naciskiem na budowę fotoanody z warstwą półprzewodnika, metodom osadzania TiO₂, charakterystyce optycznej i morfologicznej otrzymanych filmów. Zamieszczono wyniki badań testowych ogniw DSSC wytworzonych w Laboratorium ML System S.A. dotyczących wpływu grubości warstw aktywnych na parametry określające ich sprawne działanie. Badania prowadzone przez wiele ośrodków naukowych potwierdzają, iż takie ogniwa mają dużą przewagę nad powszechnie stosowanymi ogniwami krzemowymi. Głównym powodem jest stosunkowo niski koszt materiałów i brak zapotrzebowania na zaawansowane technologie produkcyjne. Ponadto zastosowanie szerokiej gamy kolorów i kontrola transparentności stwarza możliwość wykorzystania DSSC jako elementu zintegrowanego z elewacją budynku.

16

Photocatalytic degradation of the organic compounds enhanced by chemical oxidants

51%

Dziedzic J. , Nowak P. , Warszyński P. , Haber J.

Elektronika : konstrukcje, technologie, zastosowania

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2012

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tom Vol. 53, nr 6

115-117

EN

We demonstrated that more than 50% of humic acid may be removed from the solution simply by its adsorption on the titania surface if the concentration of TiO₂ in suspension is high enough. 100% removal of HA can be achieved even at relatively low dosage of TiO₂ (100 mg I−¹) if UV illumination of the suspension is applied for sufficiently long time (at least 3 hours). Addition of oxidant to the solution containing titania suspension and dissolved humic acid greatly enhances the activity of TiO₂ in the process of decomposition of organic substances. We showed that more than 90% conversion of HA can be obtained when sodium persulphate was applied as chemical oxidant already after one hour. Therefore, the synergistic effect was observed when TiO₂ and Na₂S₂O₈ were used simultaneously for the removal of humic substances. The photodecomposition efficiency of in the UV/TiO₂/Na₂S₂O₈ system was greater than of one with H₂ O₂ used as oxidant. Moreover, contrary to hydrogen peroxide, sodium persulphate is rather stable in room temperature. Therefore, use of Na₂S₂O₈ as oxidant supporting photocatalytic removal of humic substances from potable water should be preferred.

17

Modeling the contact of stiff and soft bodies with a rigid support by short range force fields

51%

Contento A. , Di Egidio A. , Dziedzic J. , Tatone A.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2009

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tom Vol. 13, No 1-2

155-181

EN

Body impact-contact dynamics is a classical subject in mechanics. Most of the papers on the subject are based on a kinematical or impulse-exchange approach. In this paper a different approach has been adopted. It consists in assigning a constitutive description for the contact forces between the boundaries of bodies which get close to each other. In particular, a field of short range forces has been used to model the interaction between an affine body and the planar surface of a fixed rigid support. These forces are able to describe the impact, friction and adhesion allowing the body to have complex motions which look rather realistic. By an affine body we mean a body which undergoes affine, or homogeneous, deformations. Depending on the material, such a body can show very different behavior, from a quite rigid motion to a motion characterized by very large deformations. A soft body is assumed to be made of a viscous incompressible Mooney-Rivlin material. Though a microscopic model of surface interaction could be used in a multiscale approach, the description provided here is macroscopic only.

18

A new stand of Oxycoccus microcarpus Turcz. ex Rupr. in the region of Warmia

51%

Dynowski P. , Zrobek-Sokolnik A. , Dziedzic J.

Polish Journal of Natural Sciences

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2012

|

tom 27

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nr 3

EN

Floristic research carried out in the region of Warmia and Mazury led to the discovery, on 16 May 2011, of a small cranberry stand in a forest, in a small raised bog with enclaves characteristic of transitional moors. The discussed stand is situated in the southern part of the Olsztyn Forest Division, district 499, in the vicinity of the eastern boundary of the Lake Kośno landscape reserve.

PL

W trakcie badań florystycznych prowadzonych w województwie warmińsko-mazurskim 16.05.2011 r. stwierdzono występowanie żurawiny drobnoowocowej. Zajmowała niewielkie śródleśne torfowisko wysokie mające enklawy charakterystyczne dla torfowisk przejściowych. Opisywane stanowisko jest położone w południowej części Nadleśnictwa Olsztyn, w granicach oddziału 499, przy wschodniej granicy Rezerwatu krajobrazowego jezioro Kośno.

19

Materialy do flory Wigierskiego Parku Narodowego

51%

Jutrzenka-Trzebiatowski A. , Szarejko T. , Dziedzic J.

Parki Narodowe i Rezerwaty Przyrody

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2002

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tom 21

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nr 1

3-14

20

Chamedafne północna Chamaedaphne calyculata - nowe stanowisko na Warmii

51%

Dziedzic J. , Dynowski P. , Zrobek-Sokolnik A.

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nr 5

PL

W trakcie badań florystycznych prowadzonych w gminie Purda na terenie województwa warmińsko- mazurskiego znaleziono nowe stanowisko chamedafne północnej Chamaedaphne calyculata (L.) Moench. Znajduje się ono na śródleśnym torfowisku wysokim, oddalonym o niecałe 2 km na południowy wschód od wsi Nerwik i o 2,5 km na północny wschód od wsi Giławy, na granicy oddziałów 224f i 238a, w Nadleśnictwie Wipsowo

EN

A new location of Chamaedaphne calyculata in Poland was found during floristic investigations carried out in the commune of Purda, the Warmia-Masuria province. The new location of the leatherleaf is a high peat bog in the forest located approximately 2 km south-east of the village of Nerwik and 2.5 km north-east of the village of Giławy, at the boundary of forest sections 224f and 238a in the forest division of Wipsowo