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Wyszukujesz frazę "C.A." wg kryterium: Autor


Tytuł:
Development of a Committee of Artificial Neural Networks for the Performance Testing of Compressors for Thermal Machines in Very Reduced Times
Autorzy:
Coral, R.
Flesch, C. A.
Penz, C. A.
Borges, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/221092.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
refrigeration compressor
artificial neural networks
performance test
Opis:
This paper presents a new test method able to infer - in periods of less than 7 seconds - the refrigeration capacity of a compressor used in thermal machines, which represents a time reduction of approximately 99.95% related to the standardized traditional methods. The method was developed aiming at its application on compressor manufacture lines and on 100% of the units produced. Artificial neural networks (ANNs) were used to establish a model able to infer the refrigeration capacity based on the data collected directly on the production line. The proposed method does not make use of refrigeration systems and also does not require using the compressor oil.
Źródło:
Metrology and Measurement Systems; 2015, 22, 1; 79-88
0860-8229
Pojawia się w:
Metrology and Measurement Systems
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:
Investigations on mixture preparation for two phase adiabatic pressure drop of R134a flowing in 5 mm diameter channel
Autorzy:
Muszyński, T.
Andrzejczyk, R.
Dorao, C. A.
Powiązania:
https://bibliotekanauki.pl/articles/240440.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
adiabatic flow
frictional pressure drop
two-phase flow
flow pattern map
R134a
przepływ adiabatyczny
tarciowy spadek ciśnienia
przepływ dwufazowy
mapy przepływu
Opis:
The article presents detailed two-phase adiabatic pressure drops data for refrigerant R134a. Study cases have been set for a mass flux varying from 200 to 400 kg/m2s, at the saturation temperature of 19.4°C. Obtained experimental data was compared with the available correlations from the literature for the frictional pressure drop during adiabatic flow. Influence of mixture preparation on pressure drop was investigated, for varying inlet subcooling temperature in the heated section. The flow patterns have also been obtained by means of a high-speed camera placed in the visualization section and compared with literature observations.
Źródło:
Archives of Thermodynamics; 2017, 38, 3; 101-118
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Verifying of the finite element model of the bridge based on the vibration monitoring at differente stages of construction
Autorzy:
Hernandez, W.
Viviescas, A.
Riveros-Jerez, C. A.
Powiązania:
https://bibliotekanauki.pl/articles/230683.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
most segmentowy
identyfikacja modalna
aktualizacja modelu
model elementów skończonych
badanie
drgania otoczenia
segmental bridge
modal identification
model updating
finite element model
testing
ambient vibration
Opis:
This paper presents the results of a dynamic response evaluation of a segmental bridge during two construction stages: before connecting the final segment of the bridge and after connecting the final segment of the bridge but prior to opening the bridge to traffic. The vibration signals obtained from Ambient Vibration Testing (AVT) campaigns were processed in order to obtain the modal parameters of the bridge during the two construction stages. Modal parameters experimentally obtained for the first stage were compared with those obtained from Finite Element (FE) models considering different construction loads scenarios. Finally, modal parameters experimentally obtained for the second stage were used to update its corresponding FE model considering two scenarios, before and after the installation of the asphalt pavement. The results presented in this paper demonstrated that a rigorous construction control is needed in order to effectively calibrate FE models during the construction process of segmental bridges.
Źródło:
Archives of Civil Engineering; 2020, 66, 1; 25-40
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eco-Friendly Soaking Process Using Tannic Acid as an Alternative Bactericide
Autorzy:
Zengin, A. C. A.
Çolak, S. M.
Zengin, G.
Kiliç, E.
Powiązania:
https://bibliotekanauki.pl/articles/204698.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bactericidal
leather industry
soaking
tannic acid
środek bakteriobójczy
przemysł skórzany
moczenie
tanina
Opis:
Eco-friendly leather processes based on the usage of natural products have become a potentially attractive issue for leather industry during the last few decades. Synthetic protective chemicals like bactericides used in most soaking process are known as hazardous substances and cause tannery effluents with high concentrations of Chemical Oxygen Demand (COD). In the present study, the effect of tannic acid on microorganisms, skin, wool and effluent were investigated in order to demonstrate the applicability of tannic acid in soaking process instead of commonly used bactericides. The bacterial load (cfu/ml), COD and Nitrogen Content (N) of the soaking effluents and Total Kjeldahl Nitrogen (TKN) content of skins and wools were investigated. Application of 0.5 and 1 wt% tannic acid concentrations was more effective than commercial bactericide, while comparable results were achieved by 0.1 and 0.3 wt% tannic acid. The application of tannic acid for soaking process resulted in lower COD and N values of effluents. The results show that tannic acid has the potential to be an alternative, eco-friendly bactericide for leather industry by reducing the pollution of leather soaking process.
Źródło:
Archives of Environmental Protection; 2014, 40, 1; 3-12
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water quality management in a treatment plant using the Box-Jenkins method
Autorzy:
Redondo-Peñuela, E. A.
Rondón-Quintana, H. A.
Zafra-Mejía, C. A.
Powiązania:
https://bibliotekanauki.pl/articles/230328.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
model Box-Jenkinsa
oczyszczalnia
szereg czasowy
jakość wody
Box-Jenkins model
treatment plant
time series
water quality
Opis:
Drinking water systems are critical to society. They protect residents from waterborne illnesses and encourage economic success of businesses by providing consistent water supplies to industries and supporting a healthy work force. This paper shows a study on water quality management in a treatment plant (TP) using the Box-Jenkins method. A comparative analysis was carried out between concentrations of water quality parameters, and Colombian legislation and guidelines established by the World Health Organization. We also studied the rainfall influence in relation to variations in water quality supplied by the TP. A correlation analysis between water quality parameters was carried out to identify management parameters during the TP operation. Results showed the usefulness of the Box-Jenkins method for analyzing the TP operation from a weekly timescale (mediumterm), and not from a daily timescale (short-term). This was probably due to significant daily variations in the management parameters of water quality in the TP. The application of a weekly moving average transformation to the daily time series of water quality parameter concentrations significantly decreased the mean absolute percentage error in the forecasts of Box-Jenkins models developed. Box-Jenkins analysis suggested an influence of the water quality parameter concentrations observed in the TP during previous weeks (between 2-3 weeks). This study was probably constituted as a medium-term planning tool in relation to atypical events or contingencies observed during the TP operation. Finally, the findings in this study will be useful for companies or designers of drinking water treatment systems to take operational decisions within the public health framework.
Źródło:
Archives of Civil Engineering; 2020, 66, 3; 125-137
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Analysis of the Phase Transitions in BNT-BT Lead-Free Ceramics Around Morphotropic Phase Boundary by Mechanical and Dielectric Spectroscopies
Autorzy:
Silva Jr, P. S.
Diaz, J. C. C. A.
Florêncio, O.
Venet, M.
M’Peko, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/353072.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Lead-free piezoelectric ceramics
morphotropic phase boundary
phase transitions
mechanical spectroscopy
dielectric spectroscopy
Opis:
In this work, the syntheses and characterization by mechanical and dielectric spectroscopies of (1-x) Bi0.5Na0.5TiO3-xBaTiO3 (BNT-100xBT), with x = 0.05, 0.06 and 0.07, lead-free piezoelectric ceramics is reported. Ceramic samples of BNT-BT have been prepared by mixed-oxide method and then conventionally sintered. X-ray diffraction patterns of sintered samples, indicated for BNT-7BT the presence of tetragonal (P4mm) complex perovskite structure, whereas for BNT-5BT and BNT-6BT the samples exhibit a mixture of tetragonal (P4mm) and rhombohedral (R3c) crystalline phases, which reveal the presence of a morphotropic phase boundary (MPB) in the BNT-BT system. Measurements of internal friction, Q-1, and the storage modulus, E’, as a function of temperature at various frequencies were carried out in a Dynamic Mechanical Analyzer (DMA), in the temperature range from 0ºC to 600ºC. Dielectric profiles are recorded in the frequency range from 1kHz to 100kHz and the temperature range from room temperature to 475ºC. Mechanical loss spectra obtained for investigated compositions of BNT-BT samples showed different frequency-independent anomalies. Two main anomalies for BNT-5BT and BNT-6BT, observed around 100ºC and 430ºC were associated with the ferroelectric-antiferroelectric and antiferroelectricparaelectric phase transitions, respectively. The results obtained from mechanical loss measurements were supported by dielectric relaxation spectra. For BNT-7BT, outside the MPB, four different frequency-independent processes were observed.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 17-20
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and Physical Parametric Analysis of a SEN with Flow Conditioners in Slab Continuous Casting Mold
Autorzy:
Gonzalez-Trejo, J.
Real-Ramirez, C. A.
Miranda-Tello, R.
Rivera-Perez, F.
Cervantes-de-la-Torre, F.
Powiązania:
https://bibliotekanauki.pl/articles/351515.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
submerged entry nozzle
fluid-flow modifiers
continuous casting of steel
mold flow patterns
turbulence
Opis:
Some of the most recent technologies that improves the performance in continuous casting process has installed infrastructure outside the mold to modify the natural fluid flow pattern to obtain a quasi-steady condition and promote a uniform solidified shell of steel. The submerged entry nozzle distributes the liquid steel in the mold and can be used to obtain the flow symmetry condition with external geometry improvements. The fluid flow conditioners were located near the outlet ports of the nozzle. The aim of the modifiers is to impose a pseudo symmetric pattern in the upper zone of the mold by inhibiting the fluid exchange between the zones created by conditioners. This work evaluates the effect of the thickness and length of the fluid-flow modifiers on the overall performance of the submerged nozzle. These properties of the fluid-flow modifiers were normalized based on two of the geometric dimensions of the standard equipment. Numerical and physical simulations suggest that the flow modifier should be as thin as possible.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 927-946
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SVC placement for voltage constrained loss minimization using self-adaptive Firefly algorithm
Autorzy:
Selvarasu, R.
Kalavathi, M. S.
Rajan, C. Ch. A.
Powiązania:
https://bibliotekanauki.pl/articles/140931.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Firefly algorithm
loss minimization
SVC
voltage profile
Opis:
Static Var Compensator (SVC) is a popular FACTS device for providing reactive power support in power systems and its placement representing the location and size has significant influence on network loss, while keeping the voltage magnitudes within the acceptable range. This paper presents a Firefly algorithm based optimization strategy for placement of SVC in power systems with a view of minimizing the transmission loss besides keeping the voltage magnitude within the acceptable range. The method uses a self-adaptive scheme for tuning the parameters in the Firefly algorithm. The strategy is tested on three IEEE test systems and their results are presented to demonstrate its effectiveness.
Źródło:
Archives of Electrical Engineering; 2013, 62, 4; 649-661
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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