Wyniki wyszukiwania - Biblioteka Nauki

1

Alluvial deposits as a subsoil and material for basic hydro-technical constructions

100%

Wierzbicki J. , Stefaniak K.

Journal of Ecological Engineering

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2015

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tom Vol. 16, nr 5

176--182

EN

The article presents an analysis of geotechnical parameters of the alluvial deposit (the areas of the Vistula and Warta river valleys) with a view to using the soil as an earth construction material and as a foundation for buildings constructed on the grounds tested. Strength and deformation parameters of the subsoil tested were identified by the CPTU (cone penetration test) and DMT (flat dilatometer test) methods, as well as by the vane test (VT). The article includes the analysis of overconsolidation process of the soil tested and a formula for the identification of the overconsolidation ratio OCR. Equation 4 reflects the relation between the undrained shear strength and plasticity of the silts analyzed and the OCR value. The analysis resulted in the determination of the Nkt coefficient, which might be used to identify the undrained shear strength of both sediments tested. On the basis of a detailed analysis of changes in terms of the constrained oedometric modulus M0, the relations between the said modulus, the liquidity index and the OCR value were identified. Mayne’s formula (1995) was used to determine the M0 modulus from the CPTU test. The usefulness of the alluvial deposit as an earth construction material was analysed after their structure had been destroyed and compacted with a Proctor apparatus. In cases of samples characterized by different water content and soil particle density, the analysis of changes in terms of cohesion and the internal friction angle proved that these parameters are influenced by the soil phase composition. On the basis of the tests, it was concluded that the most desirable shear strength parameters are achieved when the silt is compacted below the optimum water content.

2

Constraining the contemporary crustal deformation in Italy with geodetic data

100%

Caporali A. , Martin S. , Massironi M.

Reports on Geodesy

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2000

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tom z. 8/54

179-193

EN

Using the EUREF 97 velocities as a velocity datum, we have computed velocities of additional, permanent GPS stations in Italy from week 995 to week 1060 (30 January 1999 to 6 May 2000), and the components of a two dimensional, horizontal strain rate tensor. When examined in the context of independent geological, seismological and geophysical knowledge, the map of the geodetically inferred strain rate field shows several interesting correlation with fault plane solutions and the geometry of preexisting faults. Our kinematic model features an extensional regime on theLigurian and Thyrrenean sea, along and West of the Apennines, up to the Adria shore, and compression in the Friuli region. In the Channel of Sicily, the relative motion of Lampedusa and Noto results in an extension, which fits the aseismic deformation pattern in the Pantelleria Rift system. The maximum deformations occur in the Central Apennines, with and extensional strain rate of 27 10(-9) yr(-1) and in the Southern Appenines, with and extensional strain rate of 23 10(-9) yr(-1). In areas characterized by intense fracturing, and superposition of fault system with different attitudes and trends, the GPS station are to sparce to account for the short wavelenght changes in stress regime. This lack of spatial resolution is evident in the Western Po Plain, or in the Messina strait, where the regime clearly changes on a shorter scale than the average distans beteen the GPS stations in those areas. With these exceptions , we conclude that the information coming from the geodetic strain rate data fits the broad scale neotectonic pattern inferred from several large scale faults, fault plane solutions of recent, shallow earthquakes, and other geophysical indicators of the stress regime.

3

Deformacje pogórnicze generujące proces nieciągły

100%

Piwowarski W.

Zeszyty Naukowe. Górnictwo / Politechnika Śląska

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2008

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tom z. 283

191-202

PL

W pracy przedstawiono rozważania dotyczące procesu deformacji terenu górniczego charakteryzującego się nieciągłymi przemieszczeniami. Zmiany struktury górotworu z jednego stanu w inny przechodzą tu przez destrukcję ośrodka. Analizę procesu ze względu na niejednoznaczność prowadzono w przestrzeni zmiennych losowych. Możliwe zajścia przedmiotowego zdarzenia zdefiniowano jako miarę probabilistyczną. Cel utylitarny to oszacowanie stanu zagrożenia terenu górniczego wystąpieniem nieciągłości o charakterze powierzchniowym lub w podobszarze wpływu eksploatacji podziemnej.

EN

The present paper concerns the process of mining area deformation characterized by discontinuous dislocations. We can observe here the transformation of rock mass structure which changes from one state into another by means of medium destruction. By reason of ambiguity, the analysis of the process has been carried out in the space of random variables. The possible occurrence of the discussed event has been defined as probability measure. The practical aim of the study is to estimate the state of hazard to mining area caused by the possible appearance of discontinuity within the subregion of underground exploitation influence.

4

Prognozowanie wpływu prędkości postępu frontu wybierania na przebieg deformacji w czasie

100%

Strzałkowski P.

Zeszyty Naukowe. Górnictwo / Politechnika Śląska

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2008

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tom z. 283

253-263

PL

W pracy przedstawiono przykład prognozy wpływu prędkości wybierania na przebieg deformacji w czasie. Obliczenia przeprowadzono na podstawie analiz wyników pomiarów i własnych modeli opisu deformacji chwilowych.

EN

The influence of face advance speed on mining subsidence rate has been presented in the paper. Calculations were executed on the basis of results geodetic measurements as well as own mathematical model of land surface deformations description in transient state.

5

Densification behaviour of carob powder

100%

Akangbe O. L. , Adamovský R. , Blahovec J. , Rutkowski K.

Infrastruktura i Ekologia Terenów Wiejskich

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2018

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tom nr IV/1

1099--1100

EN

The behaviour of carob (Ceratonia siliqua L.) powder relevant to its densification at low pressure was determined given different equipment aspect ratios (0.5, 1.0 and 1.5) and varying rates of deformation (5.5, 10 and 14.5 mm min-1). The effects of both parameters were examined through the analysis of variance and trends were fitted to observed mechanical responses using standard regression technique. Both aspect ratio and the time rate of deformation had highly significant effects on the material’s response to load. Strain rate and specific power requirement were power functions of the equipment’s aspect ratio, at all rates of deformation. These findings furnish insights on mechanical response in compressed food powders which are applicable in modelling related food handling and processing systems.

6

Bargmann measures for t-deformed probability

100%

Krystek A. D. , Wojakowski Ł. J.

Probability and Mathematical Statistics

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2014

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tom Vol. 34, Fasc. 2

279--291

EN

It is shown that the Bargmann representation of a t-deformed probability measure can be obtained by taking away some t-dependent amount of mass at zero of the Bargmann representation of the original measure and scaling of the remaining part. This allows us to formulate conditions on existence of the Bargmann representation of a t-deformed probability measure and to study some prominent examples.

7

Eksperymentalno-analityczne opracowanie metodyki dla wyznaczenia parametrów kryterium odkształceniowego oraz zastosowanie ich dla oszcowania wytrzymałości konstrukcji

100%

Andrejkiw O. , Sztajura S.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

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2001

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tom Z. 73

501-509

PL

W pracy zaproponowano eksperymentalno-analityczną metodykę dla wyznaczania rozwarcia wierzchołka pęknięcia beta oraz naprężenia kohezyjnego sigmao dla średnio i wysoko plastycznych stali. Przeanalizowano wpływ szeregu czynników na krytyczną wartosść beta 1c i wykazano dominujący wpływ plastycznej składowej przemieszczania brzeg ów peknięcia. Zaproponowano poprawki do normy wyznaczenia beta w szerokim zakresie obciążeń. Ustalono warunki określące jednoznaczność naprężeń kohezyjnych sigmao w zależności od sposobu obciążenia i współczynnika skali oraz ich zależność od zmiany charakterystyk wytrzymałości materiału w ramach modelu - betac i uogółnionego modelu-betac.

EN

The experimental-analytical approach for determination of crack opening displacement beta and cohesive stress sigma o for middle-and low-strength steels is proposed. The influence of several factors on critical crack opening displacement beta 1c is considered and the dominantinfluence on it of plastic component of crack faces displacement is shown. The standard for determination of sigma in the whole range of the applied loading is specified. The dependence between cohesive stress sigma o and the force loading condition, scale factor of the mechanical characteristics both within the framework of betac-model and generalized sigmac-model is established.

8

Auxetic materials — A review

100%

Carneiro V. H. , Meireles J. , Puga H.

Materials Science Poland

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2013

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tom Vol. 31, No. 4

561--571

EN

Auxetic materials are endowed with a behavior that contradicts common sense, when subjected to an axial tensile load they increase their transverse dimension. In case of a compression load, they reduce their transverse dimension. Consequently, these materials have a negative Poisson’s ratio in such direction. This paper reviews research related to these materials. It presents the theories that explain their deformation behavior and reveals the important role represented by the internal structure. Their mechanical properties are explored and some potential applications for these materials are shown.

9

A q-deformed particle algebra with a unique d-dimensional representation

100%

Tekin Ş. , Arik M.

Open Physics

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2011

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tom 9

|

nr 4

996-1001

EN

We present an algebra generated by a single pair of creation and annihilation operators b and b*. We prove that the algebra has a unique d-dimensional representation. Physically this algebra corresponds to a system where there are at most d − 1 particles in a state with otherwise same quantum numbers.

10

Evolution of small-scale deformation in relation to increasing calcite cementation in the sandstones of the Magura Nappe, Outer Carpathians (Poland)

100%

Świerczewska A. , Tokarski A. K.

Biuletyn Państwowego Instytutu Geologicznego

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2001

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tom nr 396

152-153

11

Badania stanu odkształcenia w wyrobach walcowanych klinami.

100%

Pater Z.

Rudy i Metale Nieżelazne

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1999

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tom R. 44, nr 11

595-598

PL

Przedstawiono rezultaty badań stanu odkształcenia w procesie walcowania poprzeczno-klinowego (WPK). W badaniach wykorzystano metodę pomiaru twardości. Określono wpływ podstawowych parametrów procesu, tj. kątów kształtującego alfa i rozwarcia klina beta oraz stopnia gniotu delta na wielkość odkształceń. Przedstawiono pomierzone doświadczalnie rozkłady odkształceń.

EN

The results of strain investigation in cross wedge rolling (CWR) process are presented in this paper. The method of hardness measurement is used in the experiments. The influence of basic CWR parameters (a forming angle alpha, a spreading angle beta, a relative reduction delta) on the strain state is examined. The strain fields obtained experimentally are presented, too.

12

Numerical modelling of asymetric double-layer Al-Cu plate rolling process

100%

Rydz D. , Skoblik R.

Advances in Materials Science

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2006

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tom Vol. 6, nr 2

29-34

EN

An unfavourable phenomenon accompanying the process of rolling flat bimetal products is the curvature of the band on leaving the roll gap, resulting from the uneven deformation of the bimetal plate’s layers. The introduction of asymmetrical velocity or roller diameters offers a possibility to quickly and easily overcome this effect. This article presents computer research of the process of rolling double-layer Al-Cu plates. Computer simulations were performed in the commercial Forge 2D software.

13

Constitutive behaviour of steel in mushy state

100%

Petruska J. , Ridky R. , Horsky J. , Kotrbacek P.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2004

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tom z. 25

121-124

EN

Semi-solid or mushy state processing permits a material to partially solidify before shape making operations. The understanding of material behaviour in the mushy state is critical for better control of various semi-solid processes. The aim of the present study is to experimentally quantify the deformation behaviour of carbon steel in mushy states. Semi-solid specimens under upsetting deformation were evaluated at various forming rates. The temperature of specimens was carefully controlled to keep the solid fraction constant. Based on the experiments, material parameters of the Perzyna's constitutive model are identified. Good correlation between simulated and measured results of the compression force was observed.

14

Rozkłady prędkości odkształcania w procesach wyciskania metali

100%

Materniak J. , Starczewska A.

Archiwum Technologii Maszyn i Automatyzacji

|

1999

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tom Vol. 19, Nr 1

87-95

PL

W pracy analizowano metodą linü poślizgu pola prędkości odkształcania w procesach wyciskania współbieżnego osiowo-symetrycznego wyrobu pełnego i wyciskania przeciwbieżnego osiowo-symetrycznego wyrobu drążonego. W szczególności przedstawiono zmiany prędkości odkształcania wzdłuż osi wypraski w funkcji stopnia odkształcenia i prędkości liniowej stempla. Obliczenia sprawdzono w próbach doświadczalnych nadplastycznego wyciskania stopu aluminiowo-cynkowego, które wykonano w Zakładzie Obróbki Plastycznej Politechniki Poznańskiej.

EN

By means of slip lines there have been determined fields of deformation speed in direct extrusion process of axial - symmetrical product as well as fields of deformation speed in indirect extrusion process of hollowed axial - symmetrical product. Deformation speed changes along the axis of die stamping have been presented as function of deformation value and a linear speed of the punch. Boundary conditions, applied in calculations, have been assumed according to the extrusion investigation results. The investigations have been carried out on the equipment désigned and performed in Division of Plastic Working, Poznan University of Technology. The equipment is generally applied for technological investigations of aluminium - zinc alloy in conditions of its superplasticity forming.

15

Ocena efektów działania obciążeń eksploatacyjnych w materiałach konstrukcyjnych

100%

Kowalewski Z. L.

Przegląd Mechaniczny

|

1998

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tom nr 15

5-15

PL

Przedstawiono doświadczalną analizę efektów wynikających z różnych form wstępnej deformacji wprowadzanej w materiałach podczas eksploatacji lub w trakcie procesu wytwarzania gotowych elementów konstrukcyjnych lub półwyrobów w postaci prętów, rur oraz blach, w której uwzględniono rodzaj materiału, typ, wielkość oraz kierunek wstępnej deformacji plastycznej; na podstawie doświadczalnie określonych powierzchni plastyczności dokonano identyfikacji zmian właściwości mechanicznych pojawiających się w materiałach, w wyniku zastosowania niektórych procesów technologicznych powszechnie wykorzystywanych przy produkcji wybranych półwyrobów.

EN

An experimental analysis is presented of the effects resulting from different forms of predeformation put into materials during operation of production process of finished constructional elements or semi-finished products such as bars, pipes and sheet. In the analysis account was taken of the kind of material, type size and direction of the plastic predeformation.

16

Eksperimental'nye issledovanija deformiruemosti sekcii rezinoarmirovannoj gusenicy

100%

Zdanvic C. , Plisc V. , Ravino V.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

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2002

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tom Z. 53(241)

333-339

EN

In order to obtain functional relations enabling to calculate deformations and rigidity of the rubber-track at its stretching, lateral bending, tangential and lateral shear protective layers, experiments were carried out and statistical analysis was applied. The tests were conducted on the bench, specially fitted for this purpose. During the experiment, the values of the load and deformations caused by the load were gauged. The results of the analysis were presented. The equations of regression for defining deformability of a rubber-track were derived, and the formulas for calculating its rigidity were presented.

17

Morphological modeling and deformation of 3D objects

100%

Boivin S. , Gagalowicz A. , Horry Y.

Machine Graphics and Vision

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2000

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tom Vol. 9, No. 1/2

263-280

EN

This paper decribes a new set of techniques based upon laws of object composition for the modeling and animation of deformable objects. They presemt some similarities with logical or morphological operations. This method is unique because the volume of the merged object is held constant with respect ti its constituents. Composition from two pbjects is allowed for general shapes which may have very different topologies. These techniques are applied towards shapes which are approximated by a poluhedral description. When integrated into a modeler, they can be used as modeling tools, animation tools, deformation tools or even morphing tools depending on how they are handled. One of the advantages of these tools is that the user may easily deduce the procedure to follows in order to obtain a given result.

18

Application of the GTN Model to Numerical Simulation of Distaloy AB Sinters Behaviour Under Complex Loading Conditions

100%

Madej L. , Perzyński K. , Składzień M. , Tkocz M. , Rosiak M. , Grosman F.

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19

Influence of mine activity onto slope deformation in landslide terrain

100%

Marschalko M.

Górnictwo i Geoinżynieria

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2004

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tom R. 28, z. 3

19-26

EN

Slope deformation of Doubrava - Vrcholec that occured in district Karvina in village Doubrava represents slope deformation reactived by mining effects. Also rainfall had invincible influence on slope movement. Greatest movements temporally evidently correlate with mining of most thick seams of mine. Objective area is situated in efficient distance of mining activity of both mining fields.

PL

Deformacja zbocza Doubrava - Vrcholec, zlokalizowanego we wsi Doubrava w powiecie Karvina, stanowi przykład deformacji terenu w wyniku eksploatacji górniczej. Na ruchy masowe mają również wpływ opady atmosferyczne. Największe przemieszczenia ewidentnie korelują z eksploatacją najgrubszych pokładów w kopalniach Doubrava i CSA. Omawiany teren jest usytuowany w wystarczająco dużej odległości od obu pól eksploatacyjnych.

20

Effects of hot chips in dry cutting processes on the temperature field and displacement of the machine tool table

100%

Albrecht T. , Thiem X. , Penter L. , Ihlenfeldt S.

Journal of Machine Engineering

|

2019

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tom Vol. 19, No. 3

31--42

EN

In machining up to 75% of the geometrical variations of work piece, features are caused by thermally induced deformations of machine components [1]. Since in dry cutting up to 80% of the thermal energy is stored in the chips [2], we expected a significant effect of these process-dependent heat sources on the machine accuracy. Based on preliminary simulation results, we systematically applied determined quantities of heated chips to a machine table to understand their impact on the temperature field. Temperature sensors where used to measure the temperature change on the tables surface and in the structure. Length measuring probes measured the corresponding deformations at 24 points distributed over the table. The measurements show a temperature change of 4 K at the surface and 3 K in the structure near the heat source after 6 minutes of exposure to 500°C chips. In this case, the impact on the temperature field is local but causes the bending of the table. We recorded 8 micron of thermo-elastic deformations. The results suggest that high-accuracy processes with large energy input, such as hard turning, require the heat induced into the machine structure by hot chips to be implemented into compensation methods and correction algorithms.