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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Dvojstupňové slinování pokročilých keramických materiálů s různými krystalovými strukturami / Two-step sintering of advanced ceramic materials with various crystal structures

Žalud, Pavel January 2009 (has links)
The influence of Two-Step Sintering (TSS) process on the final microstructure of oxide ceramics materials with two different crystal structures was studied. Tetragonal zirconia (stabilized with 3mol%Y2O3, particle size 90nm and 140nm ) and cubic zirconia (8mol%Y2O3, 70nm) powders were cold isostatically pressed and pressure less sintered with different heating schedules. The microstructures achieved with TSS method were compared with microstructures achieved with conventional Single-Step Sintering schedule (SSS). The results showed that the efficiency of the TSS of these oxide ceramics was more dependent on their crystal structure than on their particle size and green body microstructure. The method of TSS brought only negligible improvement of the microstructure of tetragonal zirconia ceramics. On the other hand, TSS was successful in the sintering of cubic zirconia ceramics; it led to a decrease in grain size by a factor of 2.
202

ZBROJOVKA BRNO / ZBROJOVKA FACTORY BRNO

Smejkalová, Veronika January 2014 (has links)
This diploma project deals with a post-industrial factory area Zbrojovka Brno. It proposes a strategy for its revitalisation and development. On contrary to official studies of one time reconstruction and creation of a residential site, the proposal brings an idea of step by step transformation into a multifunctional city quarter with preservation and new use of original industrial architecture. The strategy has four main phases, which are characterised by addition of functions, metamorphoses of public space and opening of the area and connecting it to neighbourhoods. After the four phases, the area should become a healthy and sustainable city with a compact structure with mixed functions, high quality public spaces linked with greenery, sustainable system of transportation and energetic concept and with use of community sharing.
203

Effect of different silanes’ composition on physico-chemical characteristics of silica particles synthesized via one step preparation method

Firsching, Matilda, Heinö, Evelina, Naij, Saga, Scullman, Christoffer, Sinnott, Oliver, Svensson, Ingrid January 2022 (has links)
No description available.
204

Sound Radiated from Turbulent Flow over Two and Three-Dimensional Surface Discontinuities

Awasthi, Manuj 13 November 2015 (has links)
Measurements have been performed to understand the sound source mechanism in turbulent boundary layer flow over two and three-dimensional surface discontinuities whose height is smaller than the incoming boundary layer thickness. The work was performed in two different types of boundary layers: a wall-jet flow and a conventional high Reynolds boundary layer. In the wall-jet flow, measurements of far field sound from two-dimensional forward facing steps, gaps with rounded corners and swept forward facing steps with rounded corners were made. The sound from a forward facing step is shown to exhibit effects of non-compactness. Rounding the step corner results in consistent drop in sound levels but the directivity of the sound field remains unchanged. The sound from gaps is dominated by the forward step component and remains unaffected by rounding of the backward step portion. The sound from swept forward facing steps was found to approximately obey an acoustic sweep independence principle up to a sweep angle of 30 deg when the spanwise inhomogeneity in the flow is accounted for using a simple source distribution model. Sweep independence is also observed for steps with corner rounding radii up to 25% of the step height. The work performed in the high Reynolds number boundary layer included measurements on forward facing steps with rounded corners and a three-dimensional circular embossment with the same height as the forward step. The highest Reynolds number based on discontinuity height achieved in this work was approximately 93,000. The results show that rounding the forward step corner has the same qualitative effect on far field sound as in the wall-jet boundary layer. Quantitatively, for similar boundary layer edge velocity the sound is higher than in the wall-jet flow. The near field measurements show that the separation bubble downstream of the step shrinks as the step corner is rounded while the bubble upstream remains unaffected by it. The unsteady surface force in the lower half of the vertical face of the step was found to be independent of corner rounding. The force on the downstream surface shows similar character within the separation bubble for each rounding but decays faster with increasing downstream distance due to reduced bubble size. The unsteady force measurements were applied to the theory of Glegg et al. (2014) and the resultant of the unsteady forces on the vertical face and downstream surface placed at the top corner of the step is shown to qualitatively describe the far field sound. The acoustic sweep independence principle was applied to the far field sound from the circular embossment and it has been shown that the sound from the three-dimensional geometry can be predicted with reasonable accuracy using sound from a two-dimensional forward step with the same span. / Ph. D.
205

Mixed n-Step MIR Inequalities, n-Step Conic MIR Inequalities and a Polyhedral Study of Single Row Facility Layout Problem

Sanjeevi, Sujeevraja 2012 August 1900 (has links)
In this dissertation, we introduce new families of valid inequalities for general linear mixed integer programs (MIPs) and second-order conic MIPs (SOCMIPs) and establish several theoretical properties and computational effectiveness of these inequalities. First we introduce the mixed n-step mixed integer rounding (MIR) inequalities for a generalization of the mixing set which we refer to as the n-mixing set. The n-mixing set is a multi-constraint mixed integer set in which each constraint has n integer variables and a single continuous variable. We then show that mixed n-step MIR can generate multi-row valid inequalities for general MIPs and special structure MIPs, namely, multi- module capacitated lot-sizing and facility location problems. We also present the results of our computational experiments with the mixed n-step MIR inequalities on small MIPLIB instances and randomly generated multi-module lot-sizing instances which show that these inequalities are quite effective. Next, we introduce the n-step conic MIR inequalities for the so-called polyhedral second-order conic (PSOC) mixed integer sets. PSOC sets arise in the polyhedral reformulation of SOCMIPs. We first introduce the n-step conic MIR inequality for a PSOC set with n integer variables and prove that all the 1-step to n-step conic MIR inequalities are facet-defining for the convex hull of this set. We also provide necessary and sufficient conditions for the PSOC form of this inequality to be valid. Then, we use the aforementioned n-step conic MIR facet to derive the n-step conic MIR inequality for a general PSOC set and provide conditions for it to be facet-defining. We further show that the n-step conic MIR inequality for a general PSOC set strictly dominates the n-step MIR inequalities written for the two linear constraints that define the PSOC set. We also prove that the n-step MIR inequality for a linear mixed integer constraint is a special case of the n-step conic MIR inequality. Finally, we conduct a polyhedral study of the triplet formulation for the single row facility layout problem (SRFLP). For any number of departments n, we prove that the dimension of the triplet polytope (convex hull of solutions to the triplet formulation) is n(n - 1)(n - 2)/3. We then prove that several valid inequalities presented in Amaral (2009) for this polytope are facet-defining. These results provide theoretical support for the fact that the linear program solved over these valid inequalities gives the optimal solution for all instances studied by Amaral (2009).
206

Effect of Step Change in Growth Speed During Directional Solidification on Array Morphology of Al-7 wt% Si Alloy

Pakiru, Swapna January 2011 (has links)
No description available.
207

Points of High Order on Elliptic Curves : ECDSA

Kouchaki Barzi, Behnaz January 2016 (has links)
This master thesis is about Elliptic Curve Digital Signature Algorithm or ECDSA and two of the known attacks on this security system. The purpose of this thesis is to find points that are likely to be points of high order on an elliptic curve. If we have a point P of high order and if Q = mP, then we have a large set of possible values of m. Therefore it is hard to solve the Elliptic Curve Discrete Logarithm Problem or ECDLP. We have investigated on the time of finding the solution of ECDLP for a certain amount of elliptic curves based on the order of the point which is used to create the digital signatures by those elliptic curves. Method: Algebraic Structure of elliptic curves over finite fields and Discrete logarithms. This has been done by two types of attacks namely Baby Step, Giant Step and Pollard’s Rho and all of the programming parts has been done by means of Mathematica. Conclusion: We have come into a conclusion of having the probable good points which are the points of high order on elliptic curves through the mentioned attacks in which solving the ECDLP is harder if these points have been used in generating the digital signature. These probable good points can be estimated by means of a function we have come up with. The input of this function is the order of the point and the output is the time of finding the answer of ECDLP.
208

Formy závěrečného hodnocení ve vzdělávacím programu Začít spolu / Forms of final evalution in the educational program Step by Step

Šimáčková, Lenka January 2012 (has links)
This Diploma Thesis covers the final evaluation topic in the educational program Step by step. In particular, it deals with the verbal description as a specific form of evaluation. In the theoretical part, the Thesis describes the Step by step program in general and within the contexts of its implementation into the Czech local educational system. The Thesis outlines the scope of the program and the applicable ways of evaluation. The second chapter deals with evaluation in general. Various kind and purpose of evaluation have been described in detail. Particular attention has been paid to the verbal evaluation as such. The research section of the Thesis studies and describes the various ways of wording and formulation in the verbal evaluation specifically. It covers both content and form of the final verbal evaluation. Key Words Program Step by step Evaluation Continuous evaluation Final evaluation Verbal evaluation Expected outcomes
209

Význam komunitních kruhů a ranních dopisů v primárním vzdělávání / Importance of Community cirles and morning letters in primary education

Pišlová, Zuzana January 2012 (has links)
In my diploma thesis I am examining the importance of community circles and morning letters in primary education. I would like to give an explanation of the term community circle especially focusing on the community circles in the programme Step by Step. These were particularly inspiring for me. I am also looking into the community circles from the point of view of the Framework Educational Programme and acquiring key competencies. It is, indeed, in the community circles that the social and communication competencies are developed. The goal of my thesis is above all stating the terms of smooth establishment of a community circle. I hope to offer guidelines for a start-up of community circles and the development of short activities used in morning circles. I also suggest examples of various morning letters useful in any school. Keywords: community circles, morning letter, key competencies, Step by Step program, rules, communication, secure environment
210

Návrh strategického plánu Asociace hráčů ledního hokeje / Ice Hockey Player's Association Strategic Plan Project

Ton, Martin January 2012 (has links)
Thesis name: Ice Hockey Players' Association strategic plan project Thesis aims: The main aim is to describe both external and internal environmental forces of Ice Hockey Players' Association and to design a complex strategic plan project for a specific time period 1.8.2012 - 31.7.2015. Methods: Supportive analytical methods SWOT and STEP were used as a descriptive analysis for identifying the initial situation of the organisation. Within the bounds of the descriptive analysis, focus group, and interview were used. Results: The outcome of this thesis is a complex project of Ice Hockey Players' Association strategic plan based on results of used analyses. Keywords: Players' association, Ice hockey, Strategic plan, SWOT analysis, STEP analysis, Non-profit organization.

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