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Tytuł:
Separation of isochromatics and isoclinics phasemaps for the photoelastic technique with use phase shifting and a large number of high precision images
Autorzy:
Magalhaes, C. A.
Neto, P. S.
Magalhaes Jr P. A., A.
de Barcellos, C. S.
Powiązania:
https://bibliotekanauki.pl/articles/220820.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
photoelasticity
metrology
stress analysis
strain measurement
optical measurement systems
optical interferometry
experimental techniques
Opis:
Digital photoelasticity is an important optical metrology follow-up for stress and strain analysis using full-field digital photographic images. Advances in digital image processing, data acquisition, procedures for pattern recognition and storage capacity enable the use of the computer-aided technique in automation and facilitate improvement of the digital photoelastic technique. The objective of this research is to find new equations for a novel phase-shifting method in digital photoelasticity. Some innovations are proposed. In terms of phaseshifting, only the analyzer is rotated, and the other equations are deduced by applying a new numerical technique instead of the usual algebraic techniques. This approach can be used to calculate a larger sequence of images. Each image represents a pattern and a measurement of the stresses present in the object. A decrease in the mean errors was obtained by increasing the number of observations. A reduction in the difference between the theoretical and experimental values of stresses was obtained by increasing the number of images in the equations for calculating phase. Every photographic image has errors and random noise, but the uncertainties due to these effects can be reduced with a larger number of observations. The proposed method with many images and high accuracy is a good alternative to the photoelastic techniques.
Źródło:
Metrology and Measurement Systems; 2013, 20, 1; 127-138
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Two Advanced Vision Methods Based on Structural and Surface Analyses to Detect Defects in the Erichsen Cupping Test
Autorzy:
Jasiński, C.
Świłło, S.
Kocańda, A.
Powiązania:
https://bibliotekanauki.pl/articles/353647.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
defect detection
Erichsen cupping test
laser speckle
vision system
Opis:
Due to the wide range of various sheet metal grades and the need to verify the material properties, there are numerous methods to determine the material formability. One of them, that allows quick determination of sheet metal formability, is the Erichsen cupping test described in the ISO 20482: 2003 standard. In the presented work, the results of formability assessment for DC04 deepdrawing sheet metal were obtained by means of the traditionally carried out Erichsen cupping test and compared with the resultsobtained by using two advanced methods based on vision analysis. Application of these methods allows extending the traditional scope of analysis during Erichsen cupping test by determination of the necking and strain localization before fracture. The proposed methods were compared in order to dedicate appropriate solution for the industrial application and laboratory tests respectively, where the simplicity and reliability are the mean aspects need to be considered when applied to the Erichsen cupping test.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 1041-1049
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phylogenetic inference of Ericales based on plastid genomes and implication of cp-SSRs
Autorzy:
Hazra, A.
Das, S.
Bhattacharya, S.
Sur, S
Sengupta, C.
Powiązania:
https://bibliotekanauki.pl/articles/2096423.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chloroplast genome
Ericales
phylogeny
simple sequence repeats
species tree
Opis:
Ericales is an ancient eudicot order encompassing numerous species of economic and ornamental values. Despite several phylogenomic studies, the evolutionary relationship among certain families of this group remains uncertain. The present study assessed a multilocus species tree of Ericales based on 107 chloroplast genomes. The plastome derived microsatellite motifs were also simultaneously explored to check their dynamicity in corroboration of species phylogeny and systematics. In addition to resolving the usual hierarchy, the present phylogenetic analysis enabled to resolve the persisting lineage disparity with valid statistical support. Accordingly, divergence incongruences of Primulaceae, Ebenaceae, and Sapotaceae from earlier reports were reinstated in presently inferred phylogeny, which further supported the latest transcriptome-based relationship of the corresponding group. Various SSR motif characteristics emerged following the recognition of the evolutionary pathway. Numerical variation in tetranucleotide repeats showed even intraspecific or varietal differences in Camellia sinensis. Validation of plastome microsatellite-based polymorphism among the related taxa might pave the way for future phylogenetic and population studies of this economically important group.
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2021, 102, 3; 277-283
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulations for Bobbin Tool Friction Stir Welding of Aluminum 6082-T6
Autorzy:
Hamilton, C.
Dymek, S.
Węglowska, A.
Pietras, A.
Powiązania:
https://bibliotekanauki.pl/articles/356155.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
friction stir welding
bobbin tool
aluminum
simulation
temperature
Opis:
Aluminum 6082-T6 panels were joined by friction stir welding utilizing a bobbin tool. A thermal simulation of the process was developed based upon machine torque and the temperature dependent yield stress utilizing a slip factor and an assumed coefficie nt of friction. The torque-based approach was compared to another simulation established on the shear layer methodology (SLM), which does not require the slip factor or coefficient of friction as model inputs. The SLM simulation, however, only models hea t generation from the leading edges of the tool. Ultimately, the two approaches yielded matching temperature predictions as both methodologies predicted the same overall total heat generation from the tool. A modified shear layer approach is proposed that adopts the flexibility and convenience of the shear layer method, yet models heat generation from all tool/workpiece interfaces.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1115-1123
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The late Cenomanian oyster Lopha staufferi (Bergquist, 1944) – the oldest ribbed oyster in the Upper Cretaceous of the Western Interior of the United States
Autorzy:
Hook, S. C.
Cobban, W. A.
Powiązania:
https://bibliotekanauki.pl/articles/138617.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cenomanian
oysters
U.S. Western Interior
Taxonomy
paleogeography
biostratigraphy
Sweepstake Routes
Zigzag Commissure
Twowells Tongue
Dakota Sandstone
cenoman
ostrygi
Środkowo-Zachodnie Stany Zjednoczone
systematyka
paleogeografia
biostratygrafia
Dakota
piaskowiec
Opis:
Lopha staufferi (Bergquist, 1944) is a medium-sized, ribbed, Late Cretaceous oyster with a slightly curved axis and a zigzag commissure; it appears suddenly and conspicuously in upper Cenomanian rocks in the Western Interior Basin of the United States. At maturity, the ribs on both valves thicken into steep flanks that allow the oyster to increase interior volume without increasing its exterior footprint on the seafloor. Lopha staufferi is the first (earliest) ribbed oyster in the Late Cretaceous of the Western Interior, but has no ancestor in the basin. It disappears from the rock record as suddenly as it appeared, leaving no direct descendent in the basin. In the southern part of the basin where it is well constrained, L. staufferi is restricted stratigraphically to the upper Cenomanian Metoicoceras mosbyense Zone (= Dunveganoceras conditum Zone in the north). Lopha staufferi has an unusual paleogeographic distribution, occurring in only two, widely scattered areas in the basin. It has been found at several localities near the western shoreline of the Late Cretaceous Seaway in west-central New Mexico and adjacent Arizona, and in localities 1,900 km (1,200 mi) to the northeast near the eastern shoreline in northeastern Minnesota, but nowhere in between. In west-central New Mexico and adjacent Arizona, L. staufferi is a guide fossil to the Twowells Tongue of the Dakota Sandstone.
Źródło:
Acta Geologica Polonica; 2016, 66, 4; 609-626
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mecaster batnensis (Coquand, 1862), a late Cenomanian echinoid from New Mexico, with a compilation of Late Cretaceous echinoid records in the Western Interior of the United States and Canada
Autorzy:
Hook, S. C.
Cobban, W. A.
Powiązania:
https://bibliotekanauki.pl/articles/139292.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cretaceous
hemiasteridae
North America
biostratigraphy
Bridge Creek Limestone Beds
Tokay Tongue
Rio Salado Tongue
Mancos Shale
Carthage coal field
kreda
Ameryka Północna
biostratygrafia
Opis:
Echinoids are rare in the Upper Cretaceous of the Western Interior, where fewer than 60 unique occurrences are known to date, most of these represented by only a few tests or isolated spines. A notable exception is the Carthage coal field (Socorro County, New Mexico), where more than 200 specimens of Mecaster batnensis, previously referred to as Hemiaster jacksoni Maury, 1925, have been collected from the basal Bridge Creek Limestone Beds of the Tokay Tongue of the Mancos Shale. Prolific occurrences from the same beds are known from elsewhere in west-central and southwest New Mexico. Recorded originally from the Upper Cretaceous of Algeria, M. batnensis is a small- to medium-sized, irregular echinoid that is confined to the upper Cenomanian Euomphaloceras septemseriatum Zone in New Mexico. Measurements on 169 well-preserved specimens from two localities in New Mexico document a species that is, on average, 21.0 mm long, 19.8 mm wide, and 15.1 mm tall, yielding a width/length ratio of 0.94 and a height/length ratio of 0.72. Graphs plotting width against length and height against length are strongly linear. The Western Interior echinoid record spans the entire Late Cretaceous, although there are no records from rocks of Santonian age. Localities are spread from New Mexico on the south to Alberta on the north. Preserva-tion ranges from coarse internal molds in high-energy sandstones to original tests in low-energy limestones.
Źródło:
Acta Geologica Polonica; 2017, 67, 1; 1-30
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modulation-Mode Assignment in SVD-Aided Downlink Multiuser MIMO-OFDM Systems
Autorzy:
Aust, S.
Ahrens, A.
Benavente-Peces, C.
Powiązania:
https://bibliotekanauki.pl/articles/227057.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multiple-input multiple-output system
orthogonal frequency division multiplexing
singular value decomposition
bit allocation
wireless transmission
Opis:
Multicarrier transmission such as OFDM (orthogonal frequency division multiplexing) is an established technique for radio transmission systems and it can be considered as a promising approach for next generation wireless systems. However, in order to comply with the demand on increasing available data rates in particular in wireless technologies, systems with multiple transmit and receive antennas, also called MIMO (multiple-input multiple-output) systems, have become indispensable for future generations of wireless systems. Due to the strongly increasing demand in high-data rate transmission systems, frequency non-selective MIMO links have reached a state of maturity and frequency selective MIMO links are in the focus of interest. In this field, the combination of MIMO transmission and OFDM can be considered as an essential part of fulfilling the requirements of future generations of wireless systems. However, single-user scenarios have reached a state of maturity. By contrast multiple users' scenarios require substantial further research, where in comparison to ZF (zero-forcing) multiuser transmission techniques, the individual user's channel characteristics are taken into consideration in this contribution. The performed joint optimization of the number of activated MIMO layers and the number of transmitted bits per subcarrier shows that not necessarily all user-specific MIMO layers per subcarrier have to be activated in order to minimize the overall BER under the constraint of a given fixed data throughput.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 4; 459-464
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical fault detection in rotating electrical machines using MCSA-FFT and MCSA-DWT techniques
Autorzy:
Bessous, N.
Sbaa, S.
Megherbi, A. C.
Powiązania:
https://bibliotekanauki.pl/articles/200283.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
motor current signature analysis
MCSA
discrete wavelet transform
DWT
rolling element bearing faults
rotor eccentricity
stator current spectrum
dyskretna transformata falkowa
uszkodzenia łożysk tocznych
widmo prądu stojana
Opis:
This paper presents mechanical fault detection in squirrel cage induction motors (SCIMs) by means of two recent techniques. More precisely, we have analyzed the rolling element bearing (REB) faults in SCIM. Rolling element bearing faults constitute a major problem among different faults which cause catastrophic damage to rotating machinery. Thus early detection of REB faults in SCIMs is of crucial importance. Vibration analysis is among the key concepts for mechanical vibrations of rotating electrical machines. Today, there is massive competition between researchers in the diagnosis field. They all have as their aim to replace the vibration analysis technique. Among them, stator current analysis has become one of the most important subjects in the fault detection field. Motor current signature analysis (MCSA) has become popular for detection and localization of numerous faults. It is generally based on fast Fourier transform (FFT) of the stator current signal. We have detailed the analysis by means of MCSA-FFT, which is based on the stator current spectrum. Another goal in this work is the use of the discrete wavelet transform (DWT) technique in order to detect REB faults. In addition, a new indicator based on the MCSA-DWT technique has been developed in this study. This new indicator has the advantage of expressing itself in the quantity and quality form. The acquisition data are presented and a comparative study is carried out between these recent techniques in order to ensure a final decision. The proposed subject is examined experimentally using a 3 kW squirrel cage induction motor test bed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 3; 571-582
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Monte Carlo-Based Method for Assessing the Measurement Uncertainty in the Training and Use of Artificial Neural Networks
Autorzy:
Coral, R.
Flesch, C. A.
Penz, C. A.
Roisenberg, M.
Pacheco, A. L. S.
Powiązania:
https://bibliotekanauki.pl/articles/220943.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
artificial neural networks
measurement system
measurement uncertainty
Monte Carlo method
Opis:
When an artificial neural network is used to determine the value of a physical quantity its result is usually presented without an uncertainty. This is due to the difficulty in determining the uncertainties related to the neural model. However, the result of a measurement can be considered valid only with its respective measurement uncertainty. Therefore, this article proposes a method of obtaining reliable results by measuring systems that use artificial neural networks. For this, it considers the Monte Carlo Method (MCM) for propagation of uncertainty distributions during the training and use of the artificial neural networks.
Źródło:
Metrology and Measurement Systems; 2016, 23, 2; 281-294
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impulsive Sound Detection Directly in Sigma-Delta Domain
Autorzy:
Miranda, I. D. dos S.
Lima, A. C. de C.
Powiązania:
https://bibliotekanauki.pl/articles/176966.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
impulsive signal detection
sigma-delta modulation
discrete cosine transform
Opis:
Recent implementations of Sigma-Delta (ΣΔ) converters have achieved low cost, low power consumption, and high integration while maintaining resolution as high as in Nyquist-rate converters. However, its usage implies demodulating the source signal delivered from ΣΔ modulation to Pulse-Code Modulation (PCM) on a pre-processing stage. This work proposes an algorithm based on Discrete Cosine Transform for impulsive signal detection to be applied directly on a modulated ΣΔ bitstream, targeting to reduce computational cost in acoustic event detection applications such as gunshot recognition systems. From pre-recorded impulsive sounds in ΣΔ format, it has been shown that the new method presents a similar error rate in comparison with traditional energy-based approaches in PCM, meanwhile, it reduces significantly the number of operations per unit time.
Źródło:
Archives of Acoustics; 2017, 42, 2; 255-261
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrolysis of lactose from cheese whey using a reactor with [beta]-galactosidase enzyme immobilised on a commercial uf membrane
Autorzy:
Regenhardt, S.A.
Mammarella, E.J.
Rubiolo, A.C.
Powiązania:
https://bibliotekanauki.pl/articles/184957.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
membrane bioreactor
immobilised enzyme
beta-galactosidas
lactose hydrolysis
bioreaktor membranowy
enzym unieruchomiony
beta-galaktozydazy
hydroliza laktozy
Opis:
In this study, [Beta]-galactosidase enzyme from Kluyveromyces fragilis was immobilised on a commercial polyethersulfone membrane surface, 10 kDa cut-off. An integrated process, concerning the simultaneous hydrolysis–ultrafiltration of whey lactose was studied and working conditions have been fixed at 55[degrees]C and pH 6.9, the same conditions that are used for the industrial process of protein concentration. For the immobilisation, best results were obtained using 5% (v/v) of glutaraldehyde solution and 0.03 M galactose; the total activity recovery coefficient (TARC) was 44.2%. The amount of immobilised enzyme was 12.49 mg with a total activity of 86.3 LAU at 37[degrees]C, using 5% (w/v) lactose solution in phosphate buffer (100 mM pH 6.9). The stability of the immobilised enzyme was approximately 585 fold higher in comparison with the stability of free enzyme. Multipoint covalent immobilisation improves the stability of the enzyme, thereby enhancing the decision to use the membrane as a filtering element and support for the enzyme immobilisation.
Źródło:
Chemical and Process Engineering; 2013, 34, 3; 375-385
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi Response Optimization of the Functional Properties of Rubber Seed – Shear Butter Based Core Oil Using D-Optimal Mixture Design
Autorzy:
Onyekwere, O. S.
Odiakaose, C.
Uyanga, K. A.
Powiązania:
https://bibliotekanauki.pl/articles/381034.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
core oil
rubber seed oil
shea butter
aluminum casting
rdzeń olejowy
olej kauczukowy
masło shea
odlewanie aluminium
Opis:
In this study, rubber seed/shea butter oil was used to formulate core oil. The formulated core oil was characterised. D-optimal mixture design was used for multi response optimisation of the functional properties of rubber seed-shea butter coil oil. Desirable values for some responses might be obtained from a factor combination while for others responses not so desirable values. Through multiple response optimisations, a factor setting that gives the desirable values for all responses was obtained. The selected optimum mixture setting for the formulated core oil is 65.937% Rubber seed and 34.063% Shea butter oil at desirability of 0.924. Under the optimum condition the functional properties of the core oil was found to be 39.57KN/M2, 626.85KN/M2, 36.63KN/M2, 593.906KN/M2, 412.605 and 167.309s for Green Compressive Strength, Dry Compressive Strength, Green Tensile Strength, Dry Tensile Strength, Permeability and Collapsibility respectively. The optimum conditions were validated with less than 0.2% error. The functional properties of the formulated core oil was compared to the functional properties of linseed core oil. It was found that rubber seed-shea butter core oil can be used for producing cores suitable for Aluminium casting.
Źródło:
Archives of Foundry Engineering; 2017, 17, 4; 207-223
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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