Wyniki wyszukiwania - Biblioteka Nauki

1

Experiments with the V-Detector algorithm

100%

Chmielewski A. , Wierzchoń S. T.

Systems Science

|

2006

|

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

Experimental Research and Modeling of the Air-Bag Fabric Material

80%

Bartkowski P. , Zalewski R.

|

2015

|

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.

3

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

80%

Zalewski R. , Rutkowski M.

Journal of Theoretical and Applied Mechanics

|

2018

|

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.

|

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

Semi-active linear vacuum packed particles damper

80%

Zalewski R. , Chodkiewicz P.

|

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.

6

Formal Theory and Value Judgments

80%

Kamiński M. , Lissowski G. , Świstak P.

|

tom 184

|

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.

7

Test Stand for Investigations of Magnetorheological Elastomers

80%

Skalski P.

Machine Dynamics Research

|

2016

|

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.

8

Cognitive properties of approval voting : an experimental approach

80%

Przybyszewski K. , Rzeska M. , Sosnowska H.

|

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

Lowering of exhaust emission in modern two - stroke engine

80%

Mitianiec W. , Rodak Ł.

Journal of KONES

|

2012

|

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.

10

Efektywność suszenia węgla brunatnego w suszarkach o zróżnicowanej ekspansji złoża fluidalnego

80%

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

Rynek Energii

|

2013

|

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.

11

Control valves for turbines of large output

80%

Tajc L. , Bednar L. , Sfastny M.

|

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.

12

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

|

2017

|

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.

13

Aviation Structure With a Magnetorheological Elastomer

80%

Skalski P.

Machine Dynamics Research

|

2016

|

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.

14

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

70%

Dziubińska A. , Gontarz A. , Dziedzic K.

|

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.

15

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

70%

Krepper E. , Prasser H. M.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

|

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.

16

Efficiency of the Reversed First-Price Sealed Bid Auctions with a Dynamic Run-Off. Results of Experiments

70%

Kuśmierczyk P.

Central European Journal of Economic Modelling and Econometrics

|

2015

|

nr 3

17

Advances in Fundamental Studies on Partially Filled Tribological Gaps

70%

Mueller M. , Ostermeyer G. P.

|

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.

18

Prediction of ship motions in irregular waves based on response amplitude operators evaluated experimentally in noise waves

70%

Bielicki S.

Polish Maritime Research

|

2021

|

tom nr 1

16--27

EN

The most common methods for predicting ship roll motions in a specified sea state are direct measurements of motions in a representative irregular wave realisation (time domain) or calculations of motions from response amplitude operators (RAOs) in the frequency domain. The result of the first method is valid only for the tested sea state, whilst the second method is more flexible but less accurate. RAO-based predictions are calculated assuming a linear model of ship motions in waves. RAO functions are usually evaluated by means of tests in regular waves for a limited number of frequencies and a constant wave amplitude. This approach is time-consuming and the discrete form of the RAO functions obtained for a limited number of frequencies may lead to discrepancies in the prediction of seakeeping and often does not allow the actual amplitude of the response in resonant frequency to be determined. Another challenge is the appropriate selection of wave amplitude for tests due to the considerable influence of viscous damping on roll response in irregular sea waves. There are alternative methods for the experimental determination of RAO functions and one of them is presented in this study. The presented approach allows RAO functions to be evaluated in one run by the generation of irregular waves characterised by a white or coloured noise spectrum. This method reduces the experiment duration, with almost continuous RAO characteristics obtained. The flat (white noise) and linear (coloured noise) wave spectral energy characteristics are considered in the experiment and the obtained predictions are compared with the results of accurate measurements in irregular waves.

19

Viscoplastic properties of an MR fluid in a damper

70%

Skalski P. , Zalewski R.

|

2014

|

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.

20

Modelling of the Viscoplastic Behaviour of Homogeneous Solid Propellants

70%

Pyrz M. , Zalewski R.

|

2015

|

tom Vol. 12, no. 1

159--174

EN

This study is concerned with the mechanical properties of homogenous solid propellants. The experimental results demonstrate the high strain rate sensitivity of these materials. A modified viscoplastic model of the Bodner- Partom type was applied to simulate the nonlinear behaviour of solid propellants when subjected to uni-axial loading conditions. The material parameters of the constitutive law were identified numerically using the evolutionary algorithm. The capability of the proposed approach was investigated for a representative solid fuel sample. The efficiency of the method is discussed.