Wyniki wyszukiwania - Biblioteka Nauki

1

Experiments with the V-Detector algorithm

100%

Chmielewski A. , Wierzchoń S. T.

Systems Science

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2006

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tom Vol. 32, no 4

55-63

EN

V-Detector is real-valued negative selection algorithm designed to detect anomalies in datasets containing real-valued data. Many of the previous experiments were focused on analysis of usability of this algorithm to detect intruders in computer network. Intrusion Detection System (IDS) should be efficient and reliable due to a large number of network connections and their diversity. Additionally, every connection is described as a record containing tens of numerical and symbolic attributes. We show that choosing appropriate representation of "typical" connections and smart decomposition of the learning data it is possible to obtain quite efficient and cheap algorithm detecting mom-typical connections.

2

Semi-active linear vacuum packed particles damper

80%

Zalewski R. , Chodkiewicz P.

Journal of Theoretical and Applied Mechanics

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2016

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tom Vol. 54 nr 1

311--316

EN

In this paper, the authors focus on the proposition of an innovative semi-active linear damper prototype working on the basis of granular materials. Vacuum Packed Particles (VPP) belong to the class of materials whose mechanical (rheological, dissipative) properties may be quickly changed by applying a partial vacuum inside the system. The concept of an innovative linear damper based on VPP is presented in the paper. Typical experimental results are presented to reveal changeable damping characteristics of the device. Additionally, the mathematical model is proposed to capture extraordinary features of the investigated damper.

3

The use of Vacuum Packed Particles with adaptable properties in acoustic applications

80%

Zalewski R. , Rutkowski M.

Journal of Theoretical and Applied Mechanics

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2018

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tom Vol. 56 nr 2

403--416

EN

The aim of this paper is to present possibilities of using a new type of granular media in acoustics as innovative sound absorbers. Most materials of this type have a porous or fibrous structure. It is constant, and once manufactured, does not easily change its configuration. The examined material – Vacuum Packed Particles (VPP) is of a changeable structure. It can be assumed that the acoustical absorption of such structures can be modified and partially adjusted by an external factor. First steps in an experimental approach have been made – the acquired results are optimistic. Additional tests are being planned to confirm the observed phenomenon and to apply VPP as novel materials in acoustics. Basing on the preliminary experimental tests, it can be concluded that the considered structures could become a significant part of a multilayered structure which would have controllable sound absorption properties.

4

Cognitive properties of approval voting. An experimental approach

80%

PRZYBYSZEWSKI K. , RZESKA M. , SOSNOWSKA H.

Operations Research and Decisions

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2011

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tom 21

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nr 3-4

20-31

EN

The paper summarizes two series of experiments demonstrating the cognitive properties of approval voting. The former series is devoted to mental processes induced in decision makers who use the method of approval voting. Based on cognitive effort, the use of choice strategies is presented in this paper. The observations of respondents show that most of them use relatively effortless strategy of eliminating alternatives and attributes. Few respondents use more sophisticated methods. The other series of experiments analyses the number of alternatives chosen in approval voting. It appears that the average number is not constant, even for similar votes but it depends on the subject of voting. The number of chosen alternatives and the subjective significance of the scope of voting are negatively or positively correlated in the case of special votes. The analyzed experiments show that the cognitive properties of approval voting have a diverse structure.

5

Test Stand for Investigations of Magnetorheological Elastomers

80%

Skalski P.

Machine Dynamics Research

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2016

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tom Vol. 40, No. 4

51--57

EN

The new experimental test setup for investigations of magnetorheological elastomers was conceived and constructed in the Institute of Aviation. The goal of this paper is to present the test stand, which makes determining the magnetic parameters of magnetorheological elastomers. The magnetic hysteresis curve of the magnetorheological elastomer fabricated with the carbon iron particles dispersed in natural rubber was studied in the magnetic field. The principle of operation, and results from experiment were presented.

6

Experimental Research and Modeling of the Air-Bag Fabric Material

80%

Bartkowski P. , Zalewski R.

Machine Dynamics Research

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2015

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tom Vol. 39, No. 1

143-152

EN

The response of the typical airbag's material has been extensively studied under conditions of simple tensile tests and bias extension probes, from both experimental and numerical viewpoints. The work presented here is related to the measurements of the deformation characteristics of PA 6.6 textile fabric under conditions of simple and bias extension. Obtained results confirmed that the global behavior of the investigated material can be predicted with reasonable accuracy.

7

Formal Theory and Value Judgments

80%

Kamiński M. , Lissowski G. , Świstak P.

Polish Sociological Review

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2014

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tom 184

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nr 4

409-430

EN

When we assume that a survey reveals respondents’ true attitudes we tacitly assume that the subjects understood what we are asking them about and that they had no incentive to be untruthful. In typical studies none of the two assumptions holds. Subjects are asked questions that use undefined terms and they are asked about issues they have no incentive to answer truthfully. Here we argue that a way to solve the two problems lies in constructing a formal theory of an attitude in such a way that an attitude can be derived from the answers yet when answering the questions subjects cannot possibly know that their responses reveal anything about their attitude and, hence, they have no incentive to answer insincerely.We briefly discuss a study that has the desirable properties necessary for the proper design.

8

Cognitive properties of approval voting : an experimental approach

80%

Przybyszewski K. , Rzeska M. , Sosnowska H.

Operations Research and Decisions

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2011

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tom Vol. 21, No. 3-4

21-34

EN

The paper summarizes two series of experiments demonstrating the cognitive properties of approval voting. The former series is devoted to mental processes induced in decision makers who use the method of approval voting. Based on cognitive effort, the use of choice strategies is presented in this paper. The observations of respondents show that most of them use relatively effortless strategy of eliminating alternatives and attributes. Few respondents use more sophisticated methods. The other series of experiments analyses the number of alternatives chosen in approval voting. It appears that the average number is not constant, even for similar votes but it depends on the subject of voting. The number of chosen alternatives and the subjective significance of the scope of voting are negatively or positively correlated in the case of special votes. The analyzed experiments show that the cognitive properties of approval voting have a diverse structure.

9

Efektywność suszenia węgla brunatnego w suszarkach o zróżnicowanej ekspansji złoża fluidalnego

80%

Lichota J. , Plutecki Z. , Pawlak-Kruczek H. , Czerep M.

Rynek Energii

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2013

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tom Nr 5

68--75

PL

W artykule opisano wyniki eksperymentów przeprowadzonych na dwóch suszarkach fluidalnych – ze złożem pęcherzykowym i wirowym – różniących się charakterem przepływu. Pokazano model teoretyczny oraz porównano wyniki teoretyczne z wynikami eksperymentów przeprowadzonych na obu suszarkach. Udowodniono, że model teoretyczny odtwarza zmierzone parametry suszenia.

EN

A paper describes the results of the experiments carried out on two types of dryers - with bubble bed fluidized bed and swirl dryer - differing in the nature of the flow. It shows the theoretical model and compares the theoretical compu-tations with the results of the experiments carried out on both dryers. It has been proven that the theoretical model reprodu-ces measured parameters of drying.

10

Lowering of exhaust emission in modern two - stroke engine

80%

Mitianiec W. , Rodak Ł.

Journal of KONES

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2012

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tom Vol. 19, No. 2

337-344

EN

In the article the results of experimental tests carried out on the modified SI two-stroke experimental combustion engine with direct fuel injection system and the prototype of the oxidizing catalytic converter are presented. Volumetric exhaust emissions of the most important chemical components are many times smaller than standard limits of gaseous emissions given by EU directive for the new stationary engines applied in non-road vehicles and machines Spark ignition two-stroke engine fitted with a catalytic reactor is characterized by high temperature of exhaust gases, which the energy may be used in cogeneration systems. The paper presents the test stand, volumetric concentration of the main components of exhaust gases, results of converted emissions and fuel consumption as a function of air excess coefficient at chosen rotational speeds together with the assessment of the test results. There is decreasing of CO and HC emission during increasing of air excess coefficient and a strong increase of CO2 behind the catalytic converter. Application of catalytic converter in the outflow system together with direct fuel injection of the tested two-stroke engine enables to achieve values of exhaust emission of main toxic chemical components close to automobile four stroke engines. The paper presents also the comparison of exhaust gas emission of this engine with other engines equipped with different fuelling systems. Presented work is the successor of a wide range of research work in the field of development of modern two-stroke engines carried out in the Cracow University of Technology.

11

Aviation Structure With a Magnetorheological Elastomer

80%

Skalski P.

Machine Dynamics Research

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2016

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tom Vol. 40, No. 3

123--130

EN

In the paper the application of a magnetorheological elastomer (MRE) in an aviation structure was presented. The prototype of the aviation structure with MRE was described. The original, carbon composite model set a reference value of both lift and drag coefficients for an E214 profile. Experiments were conducted in order to evaluate the influence of the magnetorheological elastomer (placed on a surface of a wing) on the overall performance. Results of experiments were depicted and discussed.

12

Control valves for turbines of large output

80%

Tajc L. , Bednar L. , Sfastny M.

Transactions of the Institute of Fluid-Flow Machinery

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2003

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tom nr 114

209-218

EN

Intensive vibration of inlet piping system was discovered during test period of 1000 MW SKODA turbine operating with inlet-saturated steam. Unwanted oscillations of the piping system required new view on construction of control parts of the turbine. Intensive research of valve models took place, numerical simulation were done. The original alternative of the valve with shaped plug was compared with the valve characterized by flat-bottom-plug and a muffler.

13

Modelling and Experimental Testing of Hybrid Joints Made of: Aluminium Adherends, Adhesive Layers and Rivets for Aerospace Applications

80%

Sadowski T. , Golewski P.

Archives of Metallurgy and Materials

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2017

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tom Vol. 62, iss. 3

1577--1583

EN

The contemporary demands in different branches of engineering require application of new multi-component materials and structural systems. Appropriately chosen joining technology can offer significant enhancement of structural system performance in terms of effectiveness, reliability, safety and other design criteria. The modern applications of complex joints are of great technological interest as they permit to combine and to enhance the individual effects of each kind of joint. This is of great importance for modern applications in different branches of engineering: aerospace, mechanical and civil. Therefore in this paper we will focus on the analysis of mechanical response of adhesive joint of aluminium strips reinforced by rivets. The aim of the paper is to investigate experimentally the mechanical behaviour of adhesive joint of aluminium strips reinforced by rivets for industrial applications in aerospace. The considered joint was subjected to uniaxial loading. The tests in this paper were performed for: • classical adhesive joint in order to investigate material parameters for numerical modelling of the hybrid joint • hybrid joining of the structural elements in order to investigate the reinforcement effect. The experiments with application of digital image ARAMIS system allowed for on-line monitoring of the deformation process of the considered joining elements. The particular distributions of displacement fields at the joint surface were estimated for any stage of loading process. Numerical modelling was performed for experimentally investigated specimens. The materials parameters, necessary for calculation, were estimated from experiments. FEA modelling was done with the help of ABAQUS code.

14

Application of a magnetorheological elastomer in an aviation structure

80%

Skalski P.

Journal of KONES

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2016

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tom Vol. 23, No. 3

449--455

EN

Magnetorheological elastomers have properties that can be altered by magnetic field. Many materials were invented more than 30 years ago, but their development and improvement over the past three decades has led to new, more varied uses of these adaptable materials. The main goal of the paper is to present and investigate the application of a magnetorheological elastomer in an aviation structure. The potential advantage of this solution is a possibility to adjust the shape of the wing during the flight by altering the magnetic field strength, which in turn causes deflection of a magnetorheological elastomer. For the purpose of the investigations, an E214 aerofoil has been selected. The original, carbon composite model set a reference value of both lift and drag coefficient for an E214 profile. A thin layer of magnetorheological elastomer was placed on the upper side of the reversed wing. In order to fully understand the effect of such structural change on an aerial profile, the new research stand was designed and manufactured for the purpose of this research in the Institute of Aviation. Experiments were conducted due to evaluate the influence of magnetorheological elastomer on the overall performance. Results of investigations were presented and discussed.

15

Modelling and experimentation of fixturing effects on workpiece quality in milling operation

80%

D'acunto A. , Mikolajcack A. , Martin P. , Gueury M.

Prace Naukowe Instytutu Technologii Maszyn i Automatyzacji Politechniki Wrocławskiej. Konferencje

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1999

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tom Vol. 72, nr 33

207-218

EN

The control of delays, cost and quality are three essential axes to ensure enterprise durability. The respect of specifications in terms of surface quality (dimensional part and surface integrity) leads to anticipate the manufacturing phase as early as possible. Cutting process, planning process and resources have to be controlled. We describe the different defect that define the milled surface quality. Then we study the fixturing influences on the surfaces quality. By the finite elements method (FEM) we modeled workpiece stress and deformation before and after milling. We used the Design of Experiments method in order to evaluate our models. We proposed to apply this method for fixturing mechanical forces and cutting forces and cutting forces study, that is to say since the process planning phase.

PL

Kontrola opóźnień, kosztów i jakości to trzy zasadnicze czynniki, od których zależy sukces przedsiębiorstwa. Przestrzeganie specyfikacji dotyczących jakości powierzchni (aspekt wymiarowy i integralność powierzchni) daje możliwość jak najwcześniejszego przewidzenia kiedy nastąpi faza wytwarzania. Procesy skrawania oraz planowanie procesu i zasobów muszą być sterowane. Opisujemy różne przyczyny usterek, które determinują jakość powierzchni frezowanych. Następnie badamy wpływ mocowania na jakość powierzchni. Używając metody elementów skończonych zamodelowaliśmy naprężenia i odkształcenia w przedmiocie obrabianym przed i po frezowaniu. Do oceny opracowanych przez nas modeli zastosowaliśmy metodę planowania doświadczeń. Proponujemy metodę badań sił mechanicznych i sił skrawania dla mocowania, począwszy od etapu planowania procesu.

16

Bedding-plane anastomoses as one of the early stages of karst evolution

80%

Calic-Ljubojevic J.

Acta Geologica Polonica

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2002

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tom Vol. 52, nr 1

111-115

EN

Bedding-plane anastomoses are braided channels of oval cross-section, connected in networks. They form along limestone bedding planes, in the lower surfaces of upper beds. Reasons for their upward growth are still not clearly defined. Preliminary experiments, based on the assumption that bedding planes in which anastomoses occur are cycle boundaries, were carried out on several samples, as a suggestion for the further research of this problem. The sampling was carried out at anastomoses profiles in cave walls, while performed experiments and analyses were: calcimetry, experimental dissolution, and analysis of thin sections. The results showed that the method of experimental dissolution of powdered samples had certain shortfalls because of the significant change of natural conditions, and that the further research should be directed primarily to calcimetry and analyses of thin sections.

17

Viscoplastic properties of an MR fluid in a damper

70%

Skalski P. , Zalewski R.

Journal of Theoretical and Applied Mechanics

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2014

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tom Vol. 52 nr 4

1061--1070

EN

The aim of this paper is to mathematically describe and analyze the viscoplastic properties of a magnetorehological (MR) fluid. The scope of the discussed research has been limited to the T-MR SiMR 132 DG damper prototype. Laboratory tests have been performed on a specially developed experimental stand with a kinematic excitation rule. On the basis of the experimental data, conventional yield points and maximum shear stresses for the analyzedMR fluid, including variable shear rate, current intensity flowing through a solenoid, liquid temperature and gap height have been analyzed. Basing on the acquired results, the parameters of Bodner-Partom constitutive equations have been estimated. The identified viscoplastic model has been used to carry out simulation tests that enabled verification of the numerical results and real experimental data.

18

Experimental and numerical investigation of one and two-phase natural convection

70%

Krepper E. , Prasser H. M.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

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2003

|

tom Z. 77

33-39

EN

Experiments were performed to investigate heating up processes of fluids in storage tanks under the influence of an external heat sourec. Several teste were carried out both with heating from the bottom an with heating from the side walls. The test tank was equipped with thermocouples for measuring the temperature distriburion and with needle probes for measuring of the local void fraction.

19

Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

70%

Dziubińska A. , Gontarz A. , Dziedzic K.

Archives of Metallurgy and Materials

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2016

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tom Vol. 61, iss. 2B

1003--1008

EN

The paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

20

Advances in Fundamental Studies on Partially Filled Tribological Gaps

70%

Mueller M. , Ostermeyer G. P.

Machine Dynamics Research

|

2018

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tom Vol. 42, No. 3

5--15

EN

Tribological scenarios with partially ﬁlled gaps can occur when either a lubricated system runs under starved lubrication or a system that usually operates under dry conditions is wetted by a ﬂuid. In order to get a detailed insight into the tribological character of partially ﬁlled gaps, it is necessary to investigate the dynamics of the ﬂuid ﬂow and its interaction with the pressure, velocity, nominal gap height and deformations. Within this problem, the total amount of ﬂuid in the gap plays a crucial role. Recent studies with novel models have shown that particularly near the fully ﬁlled regime the built up pressure is highly dependent on the ﬁlling ratio. Further studies proved that the ﬂuid forms characteristic bow waves in front of asperities thus leading to larger mean pressure values in the contact. This paper extends these ﬁndings by experimental investigations on different length scales. Special focus is on the correlation between the friction coefﬁcient and the supplied ﬂuid volume.