Wyniki wyszukiwania - BazTech

1

Zwiększanie skali procesu jednoślimakowego wytłaczania tworzyw polimerowych

Nastaj Andrzej

Polimery

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2021

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T. 66, nr 6

331--340

PL

Na podstawie badań symulacyjnych opracowano metodę zwiększania skali procesu jednoślimakowego wytłaczania tworzyw polimerowych, z zastosowaniem technik ewolucyjnych (algorytmów genetycznych). Do symulacji procesu wytłaczania stosowano program GSEM (Global Screw Extrusion Model), a do zwiększenia skali specjalnie w tym celu opracowany program GASES (Genetic Algorithms Screw Extrusion Scaling). Jako kryteria stosowano jednostkowe zużycie energii, szybkość uplastyczniania i szybkość wzrostu temperatury tworzywa. Uzyskano znaczący wzrost wydajności procesu wytłaczania.

EN

A method of scaling-up the single screw extrusion of polymeric materials has been developed based on the process simulation studies using the evolutionary techniques (genetic algorithms). The simulation tests were carried out using the GSEM extrusion simulation program, while the scaling-up was carried out on the basis of the GASES evolutionary scaling-up program specially developed for this purpose. Scaling-up has been performed according to the criteria of unit energy consumption, polymer melting rate and polymer temperature, obtaining a significant increase in extrusion throughput.

2

Review on relationship between the universality class of the Kardar-Parisi-Zhang equation and the ballistic deposition model

Sayfidinov Okhunjon, Bognar Gabriella

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 4

206--216

EN

We have analysed the research findings on the universality class and discussed the connection between the Kardar-Parisi-Zhang (KPZ) universality class and the ballistic deposition model in microscopic rules. In one dimension and 1+1 dimensions deviations are not important in the presence of noise. At the same time, they are very relevant for higher dimensions or deterministic evolution. Mostly, in the analyses a correction scale higher than 1280 has not been studied yet. Therefore, the growth of the interface for finite system size [...] value predicted by the KPZ universality class is still predominant. Also, values of [...] obtained from literature are consistent with the expected KPZ values of [...] connection between the ballistic deposition and the KPZ equation through the limiting procedure and by applying the perturbation method was also presented.

3

Evaluating the reconstruction method of satellite based monthly precipitation over Golestan province, Northern Iran

Abdollahipour Arman, Ahmadi Hassan, Aminnejad Babak

Acta Geophysica

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2021

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Vol. 69, no. 6

2305--2323

EN

Accurate gridded precipitation data with high spatial and temporal scales are required for diverse studies such as climatology, meteorology, and hydrology. Currently, one of the sources of global precipitation estimation is the satellite-based precipitation estimate products. Nonetheless, their spatial resolution is often too coarse for usage in local region and basin scales or for parameterizing of meteorological and hydrological models at regional scales. In the present paper, a reconstruction method of satellite-based monthly precipitation was developed to attain improved pixel-based precipitation data with high spatial resolution on Golestan province in Northern Iran. In this endeavor, we considered the spatially heterogeneous relationships between tropical rainfall measuring mission (TRMM) precipitation and environmental variables utilizing the moving-window regression methods, the geographically weighted regression (GWR) and the mixed geographically weighted regression (MGWR) models. By in situ observations from rain gauges in the study area, the calibration and validation were performed, and the following conclusions were derived: (1) the proposed procedure had the ability to enhance both the spatial resolution and accuracy of satellite-based precipitation estimates; (2) the monthly reconstructed precipitation using the GWR model (CC=0.69, bias=0.75) and using the MGWR model (CC=0.72, bias=0.64) outperformed the TRMM-3B43V7 data (CC=0.58, bias=0.84) against ground observations; (3) this research offered a potential solution for producing gridded precipitation estimates at high spatial resolution. remote sensing

4

Comparison of the Resampling Methods for Gridded DEM Downscaling

Nguyen Quang Minh, Nguyen Thi Thu Huong, La Phu Hien, Duong Thi Tuyet Nhung, Nguyen Thi Minh Hong, Vu Van Anh

Inżynieria Mineralna

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2019

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R. 21, nr 2/2

240--248

EN

In this paper, a comparison and evaluation of three resampling methods for gridded DEM is implemented. The evaluation was based on the results of bilinear resampling, bi-cubic and Kriging resampling methods for an experiment using both degraded and sampled datasets at 20 m and 60 m spatial resolutions. The evaluation of the algorithms was accomplished comprehensively with visual and quantitative assessments. The visual assessment process was based on direct comparison of the same topographic features in different downscaled images, scatterplots and profiles. The quantitative assessment was based on the most commonly used parameters for DEM accuracy assessment such as root mean square errors (RMSEs), linear regression parameters m and b, and correlation coefficient R. Both visual and quantitative assessment revealed greater accuracy of the Kriging over the other two conventional methods.

5

Propozycja metody zwiększania dokładności wymiarowej obiektów wykonywanych technikami przyrostowymi

Piękoś J., Siemiński P., Grygoruk R.

Mechanik

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2016

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R. 89, nr 12

1910--1911

PL

Artykuł przedstawia wyniki analizy wymiarowej obiektów wykonanych techniką przyrostową (drukiem 3D). Zaproponowano prostą metodę zwiększenia dokładności drukowanych modeli poprzez wprowadzenie współczynnika kompensującego błędy procesu. W oparciu o wyniki analizy modelu badawczego wyznaczono wartość współczynnika skalowania, który pozwolił na znaczne zmniejszenie wartości błędu względnego mierzonych wymiarów. W ramach pracy wykonano weryfikację poprawności zaprezentowanej metody z wykorzystaniem optycznego skanera 3D.

EN

This article presents the results of dimensional analysis of models which were made using 3D printing. We proposed a simple method of increasing dimensions of printed models using compensation scale factor. Scale factor allowed us to decrease relative error of measured dimensions. The verification of presented method was performed using optical 3D scanner.

6

Application of numerical modelling to scaling-up of electrically induced extraction from an organic mixture using an ionic liquid

Kamiński K., Weatherley L.R., Petera J.

Chemical and Process Engineering

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2016

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Vol. 37, nr 1

133--148

EN

Liquid-liquid extraction provides an environmentally friendly process as an alternative to azeotropic distillation, pervaporation and reverse osmosis because these techniques require the use of large amounts of energy, may involve volatile organic compounds, and operation at high pressureIonic liquids (ILs) continue to gain wide recognition as potential environmentally friendly solvents due to their unique properties. However due to their current high cost, their use in industry is seriously limited without an efficient methodology for recovery and recycle. In this paper we describe an innovative methodology for a liquid-liquid extraction process based on an electrically induced emulsion of an ionic liquid as the extracting solvent dispersed in an organic mixture. This offers a most efficient exploitation of the solvent. On the other hand we present our own design of a pilot (semi-industrial) scale extractor based on this methodology and which demonstrates effective recovery of the ionic liquid. In order to achieve this goal we used a numerical modelling tool implemented using our own simulation software based on the finite element method. We also used our original previous experience with generating and investigating liquid-liquid electrosprays using phase Doppler anemometry. Finally we present recommendations for contactor geometry and for the preferred operating conditions for the extractor.

7

Acoustic Full Waveforms as a Bridge between Seismic Data and Laboratory Results in Petrophysical Interpretation

Wawrzyniak-Guz K.

Acta Geophysica

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2016

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Vol. 64, no. 6

2356--2381

EN

Mutual relationships between geological and geophysical data obtained by using methods of different scale are presented for the Miocene sandy-shaly thin-bedded formation and for the Zechstein carbonate formation. The common basis of laboratory results, well logging and seismic data was a recognition of elastic and reservoir properties of rocks. The common basis of laboratory results, well logging and seismic data were elastic and reservoir properties of rocks. Seismic attributes calculated from acoustic full waveforms were a link between the considered data. Seismic attributes strongly depend on small changes observed in rock formation related to lithology variations, facies changes, structural events and petrophysical properties variability. The observed trends and relationships of high correlation coefficients in the analysed data proved the assumption made at the beginning of research that common physical basis is a platform for data scaling. Proper scaling enables expanding the relationships determined from laboratory and well logging of petrophysical parameters to a seismic scale.

8

Scale problems in assessment of hydrogeological parameters of groundwater flow models

Nawalany M., Sinicyn G.

Geologos

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2015

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Vol. 21, No. 3

179--185

EN

An overview is presented of scale problems in groundwater flow, with emphasis on upscaling of hydraulic conductivity, being a brief summary of the conventional upscaling approach with some attention paid to recently emerged approaches. The focus is on essential aspects which may be an advantage in comparison to the occasionally extremely extensive summaries presented in the literature. In the present paper the concept of scale is introduced as an indispensable part of system analysis applied to hydrogeology. The concept is illustrated with a simple hydrogeological system for which definitions of four major ingredients of scale are presented: (i) spatial extent and geometry of hydrogeological system, (ii) spatial continuity and granularity of both natural and man-made objects within the system, (iii) duration of the system and (iv) continuity /granularity of natural and man-related variables of groundwater flow system. Scales used in hydrogeology are categorised into five classes: micro-scale – scale of pores, meso-scale – scale of laboratory sample, macro-scale – scale of typical blocks in numerical models of groundwater flow, local-scale – scale of an aquifer/aquitard and regional-scale – scale of series of aquifers and aquitards. Variables, parameters and groundwater flow equations for the three lowest scales, i.e., pore-scale, sample-scale and (numerical) block-scale, are discussed in detail, with the aim to justify physically deterministic procedures of upscaling from finer to coarser scales (stochastic issues of upscaling are not discussed here). Since the procedure of transition from sample-scale to block-scale is physically well based, it is a good candidate for upscaling block-scale models to local-scale models and likewise for upscaling local-scale models to regional-scale models. Also the latest results in downscaling from block-scale to sample scale are briefly referred to.

9

Some methods of pre-processing input data for neural networks

Kuźniar K., Zając M.

Computer Assisted Methods in Engineering and Science

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2015

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Vol. 22, no. 2

141--151

EN

Two techniques of data pre-processing for neural networks are considered in this paper: (i) data compression with the application of the principal component analysis method, and (ii) various forms of data scaling. The novelty of this paper is associated with compressed input data scaling by the rotation (by the “stretching”) in neural network. This approach can be treated as the new proposition for data preprocessing techniques. The influence of various types of input data pre-processing on the accuracy of neural network results is discussed by using numerical examples for the cases of natural frequency predictions of horizontal vibrations of load-bearing walls. It is concluded that a significant reduction in the neural network prediction errors is possible by conducting the appropriate input data transformation.

10

The effect of anionic surfactant on the surface structure of nanofiltration membranes

Kowalik-Klimczak A., Religa P., Gierycz P., Bojarska M.

Challenges of Modern Technology

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2014

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Vol. 5, no. 2

33--38

EN

The effect of anionic surfactant on the surface structure of nanofiltration membranesAbstract: The effect of cleaning bath – sodium dodecyl sulphate solution on the surface structure of the polymer membrane used during nanofiltration of concentrated salt solutions have been presented in this paper. It was found that the use of the cleaning bath with sodium dodecyl sulphate caused a significant reduction in the separation and permeability possibilities of tested membrane.

11

Analysis of the spatial distribution between successive earthquakes occurred in various regions in the world

Marekova E.

Acta Geophysica

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2014

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Vol. 62, no. 6

1262--1282

EN

The earthquake spatial distribution is being studied, using earthquake catalogs from different seismic regions (California, Canada, Central Asia, Greece, and Japan). The quality of the available catalogs, taking into account the completeness of the magnitude, is examined. Based on the analysis of the catalogs, it was determined that the probability densities of the inter-event distance distribution collapse into single distribution when the data is rescaled. The collapse of the data provides a clear illustration of earthquake-occurrence self-similarity in space.

12

Scaling of Lagisza 460MW supercritical CFB boiler hydrodynamics

Mirek P.

Rynek Energii

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2012

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Nr 2

162--166

EN

The paper presents the results of model studies on the hydrodynamics of the world’s first supercritical circulating fluidized bed boiler Lagisza 460MWe, which were carried out on a scaling model built in a scale of 1/20 with the full geo-metrical similarity preserved. To reflect the macroscopic pattern of flow in the boiler’s combustion chamber, scaling-down was made based on three dimensionless dynamic similarity criteria of flows. A polydispersion solids mix with its fractional composition determined by scaling down the particle size distribution of the boiler’s inert material was used for the tests. The obtained results show very good agreement with the results of measurements taken on the Lagisza 460MWe supercritical CFB boiler.

PL

W artykule przedstawiono wyniki badań modelowych aerodynamiki nadkrytycznego kotła fluidalnego Łagisza CFB o mocy 460MWe, przeprowadzone na stanowisku modelowym wykonanym w skali 1/20 z zachowaniem podobieństwa geometrycznego. Dla odzwierciedlenia makroskopowej struktury przepływu skalowanie przeprowadzono w oparciu o trzy bezwymiarowe kryteria podobieństwa dynamicznego przepływów. W badaniach wykorzystano polidyspersyjną mieszaninę materiału sypkiego. Uzyskane wyniki charakteryzują się bardzo dobrą zgodnością z wynikami pomiarów przeprowadzonych na nadkrytycznym kotle fluidalnym Łagisza CFB 460MWe.

13

Nitrogen content and biomass : scaling from the tree to the forest level

Cheng D.-L., Zhong Q.-L.

Polish Journal of Ecology

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2012

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Vol. 60, nr 4

699--706

EN

Nitrogen is an essential nutrient for plant growth. Although much has been learned about its utilization and distribution within the plant body, little is known about the relationship between nitrogen content and standing biomass at the level of entire forests. Data for nitrogen content (N) and biomass (M) of 10 deciduous species in USA at the individual trees level and 37 species grown in three forest biomes (i.e. tropic, subtropics, and temperate) in China at stands level were gathered to determine the N versus M scaling relationships for different tissue- and organ-types (e.g. bark and leaves). Model Type II regression protocols were used to calculate scaling exponents and allometric constants (i.e. slopes and y-intercepts of log-log bivariate plots, respectively) between N and M to. At the level of individual plants, N scaled nearly isometrically with M for the different tissue- and organ-types (i.e. N [proportionality] M [0.97–1.04]). At the stand-level, N scaled similarly with respect to leaf, branch, and bark M, despite differences in stand size-frequency distributions and species composition. However, total stand N scaled allometrically with respect to total stem or root M and thus to total stand mass (i.e. N [proportionality] M[T] [0.77–0.87]). This was attributed to the accumulation of wood (and other ‘necromass’ tissue components that have lower N content than physiologically active tissues) in progressively older (and thus more massive) tree stands. When coupled to the scaling of N with respect to annual plant growth rates, these exponents provide important boundary conditions with which to model forest nutrient cycling.

14

Life history strategy influences biomass allocation in response to limiting nutrients and water in an arid system

Mao W., Allington G., Li Y., Zhang T., Zhao X., Wang S.

Polish Journal of Ecology

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2012

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Vol. 60, nr 3

545-557

EN

The optimal partitioning theory (OPT) predicts that a plant should allocate relatively more biomass to the organs that acquire the most limiting resource. However, variation in biomass allocation among plant parts can also occur as a plant grows in size. As an alternative approach, allometric biomass partitioning theory (APT) asserts that plants should trade off their biomass between roots, stems and leaves, and this approach can minimize bias when comparing biomass allocation patterns by accounting for plant size in the analysis. We analyzed the biomass allocation strategy of the two species: annual Setaria viridis (L.) Beauv and perennial Pennisetum centrasiaticum Tzvel from the Horqin Sandy Land of northern China by treating them with different availabilities of soil nutrient and water (added in summer and winter), and hypothesized that the two species have different patterns of biomass allocation strategy in response to different soil water content and soil nitrogen content. After taking plant size into account, the biomass allocation strategy of S. viridis and P. centrasiaticum differed in response to nitrogen and water; leaves and root:shoot ratio (RTS) of S. viridis were "true" in response to various soil nitrogen contents. The plasticity of roots was also "true" in response to fluctuation in soil water content. However, P. centrasiaticum showed a different pattern with no shift of biomass allocation strategy in response to nitrogen and water. Adjustment in organs biomass allocation pattern of S. viridis in response to nitrogen and water limitation was dramatic, this suggested that S. viridis support optimal partitioning theory (OPT). P. centrasiaticum has better tolerance to varied environments and more likely support the allometric biomass partitioning theory (APT), this characteristic may allow P. centrasiaticum to keep dominance in fragile habitats.

15

A single-parameter predictor of the effectiveness of the cavitation erosion process

Gireń B.

Scientific Problems of Machines Operation and Maintenance

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2011

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Vol. 46, nr 4

7--23

EN

A parameter pertaining to material susceptibility to cavitation damage under identified loadings is proposed. A probability mass function of cavitation loadings is suggested to represent environmental conditions and fatigue performance of a material at a specified standard regime, as the material properties are considered to control the performance of the erosion process and are suggested to be taken into account for its quantification. Therefore, the value of the parameter is assumed to follow from calculations employing the probability mass function of the loadings and fatigue characteristics of the material, as well as energy absorption in stress-strain cycle of the loading, corrected for the presence of inhibiting processes. The appropriate threshold conditions for erosion are assumed to follow from the relationship between the inverse fatigue function and the loading distribution. In this paper, a preliminary experimental verification of the correlation between the postulated parameter and the cavitation erosion parameter is carried out. The reliability and applicability of the parameter as well as the sources of inaccuracy and uncertainties are also discussed.

PL

W pracy przedstawiono wskaźnik oceny skłonności materiału do ulegania niszczeniu erozyjnemu w warunkach zidentyfikowanych obciążeń kawitacyjnych. Przyjęto założenie, że o przebiegu procesu decydują rozkład obciążeń oraz odporność zmęczeniowa materiału. Do wyznaczenia wskaźnika oceny wykorzystuje się zatem rozkład prawdopodobieństwa obciążeń jako czynnik reprezentujący warunki środowiskowe oraz standaryzowaną krzywą zmęczeniową, reprezentującą właściwości niszczonego materiału. Wartość wskaźnika jest ustalana według procedury, która obejmuje zestawienie powyższych zależności oraz wyliczenia korekcyjne, związane z absorpcją energii w cyklu zmęczeniowym i występowaniem procesów hamujących rozwój erozji. Przyjęto, że warunki progowe skutecznego niszczenia materiału określone są poprzez graniczną wartość obciążenia dla zmęczenia wysokocyklowego. Dokonano wstępnej weryfikacji istotności wskaźnika poprzez sprawdzenie występowania korelacji pomiędzy jego wartością a parametrami erozji kawitacyjnej dla określonych materiałów i warunków doświadczalnych. Przedyskutowano ponadto stosowalność wskaźnika i źródła potencjalnych błędów w określaniu jego wartości.

16

The influence of sampling point on solids suspension density applied in scaling of the hydrodynamics of a supercritical CFB boiler

Mirek P., Ziaja J.

Chemical and Process Engineering

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2011

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Vol. 32, nr 4

391-399

EN

The article presents the results of laboratory tests carried out on a scaling model of the 966MW the fluidised-bed boiler operating in the Lagisza Power Plant, made on a scale of 1:20 while preserving the geometrical similarity. The tests were carried out for scaled-down material taken from different locations on the circulation contour in the state of full boiler loading. To reflect the hydrodynamic conditions prevailing in the combustion chamber, solids with properly selected density and particle size distribution were used. The obtained results have made it possible to determine the location for taking the most representative granular material sample.

17

A simplified methodolgy for scaling hydrodynamic data from Lagisza 460 MWC supercritical CFB boiler

Mirek P.

Chemical and Process Engineering

|

2011

|

Vol. 32, nr 4

245-253

EN

The paper presents the results of model studies on the hydrodynamics of the world's first supercritical circulating fluidized bed boiler Lagisza 460 MWe, carried out on a scale model built in a scale of 1/20 while preserving the full geometrical similarity. To reflect the macroscopic pattern of flow in the boiler's combustion chamber, tests were carried out based on two dimensionless flow dynamic similarity criteria, while maintaining a constant Froude number value between the commercial and the scaled-down units. A mix of polydispersion solids with its fractional composition determined by scaling down the particle size distribution of the boiler's inert material was utilised for the tests using a special scaling function. The obtained results show very good agreement with the results of measurements taken on the Lagisza 460 MWe supercritical CFB boiler.

18

Problem efektu skalowania w pomiarach chropowatości powierzchni bombardowanej jonami

Kowalski Z., Wilk J.

Elektronika : konstrukcje, technologie, zastosowania

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2009

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Vol. 50, nr 9

74-75

PL

Jedną z właściwości morfologicznych powierzchni bombardowanej jonami jest chropowatość tej powierzchni, wyrażana różnorodnymi parametrami i rozkładami statystycznymi, odnoszonymi do wertykalnych i horyzontalnych cech jej profilu. W artykule przedstawiono wyniki badań dotyczących modyfikacji powierzchni stali nierdzewnej 1H1BN9T i tytanu prostopadłą (Θ = 0°) i ukośną (Θ = 87°) wiązką jonów argonu i kryptonu. W eksperymentach stosowano zneutralizowaną wiązkę jonów o średnicy (w płaszczyźnie katody) równej około 1 mm i energii dochodzącej do 6 keV, uzyskiwaną z jarzeniowego źródła z wnękową anodą. Badania wskazują na zależność uzyskanych wyników od przyjętej skali (scaling effect).

EN

Roughness is one of the morphological properties of ion bombarded surface that is expressed by various parameters and statistical distributions referring to vertical and horizontal features of surface roughness profile. This paper presents experimental results concerning stainless steel 1H18N9T (made in Poland) and titanium surface modification with the use of perpendicular (Θ = 0°) as well as oblique (Θ = 87°) ion beam. Argon and krypton ion beams with diameter (in cathode plane) of about 1 mm, energy up to 6 keV and ion beam density up to 0,5 mAcm⁻² from GD ion source were used in the experiments. It follows from the studies that values of roughness parameters Rα, S and Sm as well as profile bearing length ratio tp depend on scalling.

19

Skalowanie toru pomiarowego w badaniach układów izolacyjnych wysokiego napięcia metodami detekcji wyładowań niezupełnych

Zydroń P., Roehrich J.

Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

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2008

|

Nr 25

163-166

PL

Pomiary wyładowań niezupełnych (wnz) są jedną z metod badania stanu układów izolacyjnych wysokiego napięcia. W referacie przedstawiono zagadnienia związane z procedurą skalowania toru pomiarowego wnz wraz z opisem aktualnych wymagań stawianych układom generatorów impulsów wzorcowych. W oparciu o normę międzynarodową IEC-60270 ed. 3 (2000-12) opisano metodę sprawdzania poprawności działania takich generatorów oraz zaprezentowano jej praktyczną realizację. Poruszono również problematykę pomiarów w zakresie bardzo wysokich częstotliwości, nieopisaną przez w/w normę. Artykuł jest ilustrowany wynikami badań wykonanych w Laboratorium Wysokich Napięć Katedry Elektrotechniki i Elektroenergetyki AGH przy zastosowaniu wirtualnego przyrządu pomiarowego, w którym zastosowano szerokopasmowy oscyloskop cyfrowy z dedykowanym oprogramowaniem.

EN

Paper presents subject of partial discharge measurements calibration accordingly to requirements of international standard IEC60270-2000 [2]. Problems with apparent charge evaluation for measurements in UHF/VHF range are pointed out. Measuring digital system for testing of PD calibrators meeting IEC standard requirements is shortly presented and results of laboratory tests of three different calibrators and whole PD measurement system are also described.

20

Tranzystor - 60 lat minęło i co dalej?

Jakubowski A., Łukasiak L.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2008

|

R. 81, nr 5

666-671

PL

Przedstawiono historię elektroniki półprzewodnikowej ze szczególnym uwzględnieniem tranzystora MOS, trudności związane z dalszą miniaturyzacją, możliwe kierunki rozwoju oraz wybrane ograniczenia fundamentalne.

EN

The papers briefly presents the history of semiconductor electronics with emphasis on MOS transistor, difficulties associated with further miniaturization, possibile directions of development and selected fundamental limitations.