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Tytuł:
A comparative study of various models of equivalent plastic strain to fracture
Badanie porównawcze różnych modeli równoważnego odkształcenia plastycznego do pękania
Autorzy:
Mykhalevych, Volodymyr
Dobraniuk, Yurii
Matviichuk, Victor
Kraievskyi, Volodymyr
Тiutiunnyk, Oksana
Smailova, Saule
Kozbakova, Ainur
Powiązania:
https://bibliotekanauki.pl/articles/27315384.pdf
Data publikacji:
2023
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
ductile fracture criteria
fracture graph
equivalent plastic strain to fracture
stress triaxiality
plane strain
kryteria powstawania pęknięć ciągliwych
wykres pękania
równoważne odkształcenie plastyczne do pękania
trójosiowość naprężeń
naprężenie płaskie
Opis:
For more then half a centre just the same approach to the simulation of the ductile crack formation wasdeveloped independently by the scientific communities of foreign and native researchers. The importance at these studies drastically increased. A set of the characteristics, according to whichit is recommendly to perform thedetail comparison of the existing fracture models is developed. The examples of the analysis of a number of the most popular models by means of obtaining and study their analytical expressions regarding the conditions of the plane state are given. The generalized relations of the know models and a number of separate relations are obtained.
Od ponad pół wieku to samo podejście do modelowania uszkodzeń podczas odkształceńplastycznych jest opracowywane niezależnie przez zespoły naukowe złożone znaukowców zagranicznych i krajowych. W ostatnich dziesięcioleciach znaczenie tych badań dramatycznie wzrosło. Opracowano zestaw cech, zgodnie z którymi proponuje się przeprowadzenie szczegółowego porównania istniejących modeli zniszczenia. Podano przykłady analizy szeregu najpopularniejszych modeli poprzez uzyskanie i badanie ich wyrażeń analitycznych dla warunków płaskiego stanunaprężenia. Otrzymano uogólnione wskaźniki znanych modeli oraz szereg wskaźników indywidualnych.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2023, 13, 1; 64--70
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Multi-Layer Micro-Perforated Panel Structure Based on Curled Space for Broadband Sound Absorption at Low Frequencies
Autorzy:
Chu, Jiaming
Liang, Xiao
Yang, Zhen
Liang, Haofeng
Chen, Tao
Su, Liang
Zhou, Zhuo
Powiązania:
https://bibliotekanauki.pl/articles/31339792.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
micro-perforated plate
curled space
broadband sound absorption
complex frequency plane method
Opis:
In this paper, we propose a multi-layer micro-perforated panel structure based on a curled space for broadband sound absorption at low frequencies, which increases the number of perforated panel layers in a limited space using a curled space. The absorption coefficients of the structure under plane wave conditions were calculated using the transfer matrix method and the finite element method. It is demonstrated that the multilayer micro-perforated panel structure can ensure high absorption (consistently over 90%) in the frequency range of 400~5000 Hz. The sound absorption mechanism of the multi-layer micro-perforated panel structure is investigated by using the acoustic impedance along with the reflection coefficient of the complex frequency surface. In addition, we also discuss the effects of the micro-perforated panel parameters on the structural sound absorption coefficient. The results show that the proposed multi-layer micro-perforated panel structure provides an excellent solution for sound absorption in a limited space.
Źródło:
Archives of Acoustics; 2023, 48, 4; 529-538
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of out-of-plane free vibration of single damaged curved beam based on precise algorithm of structural mechanics
Autorzy:
Li, Xiaofei
Pan, Zhouyang
Guo, Hainan
Powiązania:
https://bibliotekanauki.pl/articles/2200899.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
out-of-plane curved beam
damaged
stiffness matrix
free vibration
Opis:
Based on a dynamic discrete model of an out-of-plane curved beam with a constant cur- vature, eigen-properties of the spatial curved beam structure in undamaged and damaged configurations are considered in this paper. In the literature, based on the equivalent sec- tion reduction method, a distributed damage modeling method is proposed. Accoding to Euler-Bernoulli beam theory, the stiffness matrix of shear, bending and torsion coupling is derived. Combined with the lumped mass matrix and the characteristic equation of the multi degree of freedom system, natural frequencies of the undamaged and damaged structures are calculated.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 407--414
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in body posture parameters: a four-year follow-up study
Autorzy:
Łabęcka, Marta
Powiązania:
https://bibliotekanauki.pl/articles/28761955.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
frontal plane
posture
children
postural deviations
photogrammetric method
Opis:
Body posture is an alignment of its segments relative to each other in a certain way and the relations between them. Abnormalities in the alignment of body segments or the cooperation of systems may cause postural defects. Scientific evidence showed that children of school age are more exposed to abnormalities in body posture so posture should be monitored because it is a key aspect of their body's physical health. This study aimed to evaluate changes in body posture parameters in the frontal plane in the same children at 5 and then 9 years of age. This four-year follow-up study included 67 children (29 girls and 38 boys) in preschool-age and school-age phases (the first examination at 5 years of age and the second examination at 9 years of age). Measurements of body weight and height were recorded. The computerized assessment of body posture was performed with the photogrammetric method (MORA 4 Generation). The normality of the distribution of variables was assessed with the Shapiro-Wilk test. Analysis of qualitative data was carried out using Pearson’s chi-squared test. The highest percentage of children were characterized by the deterioration in the position of the lower corners of the scapulae, taking into account the division into sex (respectively in girls 51.7 % and boys 50.0 %) and the analysis of the whole group (50.7 %). There were statistically significant differences in the position of the lower corners of scapulae (UL) between the first and second examinations in all examined children (p = 0.005). The difference in the height of the waist and in the position of the shoulders improved and deteriorated in a similar percentage in children (above 30-40 %). Generally, an improvement in body posture was observed, however, the occurred abnormalities of body posture indicate the need to continuously monitor the children's posture and implementation of preventive and corrective measures.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2023, 44; 5-14
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discussion around IR material and structure issues to go toward high performance small pixel pitch IR HOT FPAs
Autorzy:
Gravrand, Olivier
Baier, Nicolas
Ferron, Alexandre
Rochette, Florent
Lobre, Clément
Bertoz, Jocelyn
Rubaldo, Laurent
Powiązania:
https://bibliotekanauki.pl/articles/2204207.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
mid-wave infrared
focal plane array
high operating temperature
small pitch
modulation transfer function
finite element method
Opis:
In the last decade, infrared imaging detectors trend has gone for smaller pixels and larger formats. Most of the time, this scaling is carried out at a given total sensitive area for a single focal plane array. As an example, QVGA 30 μm pitch and VGA 15 μm pitch exhibit exactly the same sensitive area. SXGA 10 μm pitch tends to be very similar, as well. This increase in format is beneficial to image resolution. However, this scaling to even smaller pixels raises questions because the pixel size becomes similar to the IR wavelength, but also to the typical transport dimensions in the absorbing material. Hence, maintaining resolution for such small pixel pitches requires a good control of the modulation transfer function and quantum efficiency of the array, while reducing the pixel size. This might not be obtained just by scaling the pixel dimensions. As an example, bulk planar structures suffer from excessive lateral diffusion length inducing pixel-to-pixel cross talk and thus degrading the modulation transfer function. Transport anisotropy in some type II superlattice structures might also be an issue for the diffusion modulation transfer function. On the other side, mesa structures might minimize cross talk by physically separating pixels, but also tend to degrade the quantum efficiency due to a non-negligible pixel fill factor shrinking down the pixel size. This paper discusses those issues, taking into account different material systems and structures, in the perspective of the expected future pixel pitch infrared focal plane arrays.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144561
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Growth and characterisation of LWIR T2SL on (100)-, (211)- and (311)-oriented GaSb substrates
Autorzy:
Lubyshev, Dmitri
Fastenau, Joel M.
Kattner, Michael
Frey, Philip
Nelson, Scott A.
Flick, Ryan
Wu, Ying
Liu, Amy W. K.
Szymanski, Dennis E.
Martinez, Becky
Furlong, Mark J.
Dennis, Richard
Bundas, Jason
Sundaram, Mani
Powiązania:
https://bibliotekanauki.pl/articles/2204213.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
focal plane arrays
InAs/InAsSb
photodetectors
long wavelength infrared type-II superlattice
metamorphic buffers
superlattice period reduction
Opis:
Ga-free InAs/InAsSb type-II superlattice structures grown on GaSb substrates have demonstrated high performance for mid-wave infrared applications. However, realisation of long wavelength infrared photodetectors based on this material system still presents challenges, especially in terms of reduced quantum efficiency. This reduction is due, in part, to the increased type-II superlattice period required to attain longer wavelengths, as thicker periods decrease the wave-function overlap for the spatially separated quantum wells. One way to improve long wavelength infrared performance is to modify the type-II superlattice designs with a shorter superlattice period for a given wavelength, thereby increasing the wave-function overlap and the resulting optical absorption. Long wavelength infrared epitaxial structures with reduced periods have been realised by shifting the lattice constant of the type-II superlattice from GaSb to AlSb. Alternatively, epitaxial growth on substrates with orientations different than the traditional (100) surface presents another way for superlattice period reduction. In this work, the authors evaluate the performance of long wavelength infrared type-II superlattice detectors grown by molecular beam epitaxy using two different approaches to reduce the superlattice period: first, a metamorphic buffer to target the AlSb lattice parameter, and second, structures lattices matched to GaSb using substrates with different orientations. The use of the metamorphic buffer enabled a ~30% reduction in the superlattice period compared to reference baseline structures, maintaining a high quantum efficiency, but with the elevated dark current related to defects generated in the metamorphic buffer. Red-shift in a cut-off wavelength obtained from growths on highindex substrates offers a potential path to improve the infrared photodetector characteristics. Focal plane arrays were fabricated on (100), (311)A- and (211)B-oriented structures to compare the performance of each approach.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144568
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long wavelength type-II superlattice barrier infrared detector for CubeSat hyperspectral thermal imager
Autorzy:
Rafol, Sir B.
Gunapala, Sarath D.
Ting, David Z.
Soibel, Alexander
Khoshakhlagh, Arezou
Keo, Sam A.
Pepper, Brian J.
Hill, Cory J.
Maruyama, Yuki
Fisher, Anita M.
Sood, Ashok
Zeller, John
Wright, Robert
Lucey, Paul
Nunes, Miguel
Flynn, Luke
Babu, Sachidananda
Ghuman, Parminder
Powiązania:
https://bibliotekanauki.pl/articles/2204204.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
type-II superlattice
focal plane array
infrared detector
quantum efficiency
noise equivalent difference temperature
dark current density
anti-reflective coating
Opis:
The hyperspectral thermal imaging instrument for technology demonstration funded by NASA’s Earth Science Technology Office under the In-Space Validation of Earth Science Technologies program requires focal plane array with reasonably good performance at a low cost. The instrument is designed to fit in a 6U CubeSat platform for a low-Earth orbit. It will collect data on hydrological parameters and Earth surface temperature for agricultural remote sensing. The long wavelength infrared type-II strain layer superlattices barrier infrared detector focal plane array is chosen for this mission. With the driving requirement dictated by the power consumption of the cryocooler and signal-noise-ratio, cut-off wavelengths and dark current are utilized to model instrument operating temperature. Many focal plane arrays are fabricated and characterised, and the best performing focal plane array that fulfils the requirements is selected. The spectral band, dark current and 8-9.4 μm pass band quantum efficiency of the candidate focal plane array are: 8-10.7 μm, 2.1∙10ˉ⁵ A/cm², and 47%, respectively. The corresponding noise equivalent difference temperature and operability are 30 mK and 99.7%, respectively. Anti-reflective coating is deposited on the focal plane array surface to enhance the quantum efficiency and to reduce the interference pattern due to an absorption layer parallel surfaces cladding material.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144569
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study on compression properties of semi-reentrant filled tubular structures
Autorzy:
Wu, Dongquan
Li, Dinghe
Zhang, Zhiqiang
Chen, Jianguo
Powiązania:
https://bibliotekanauki.pl/articles/2200883.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
semi-reentrant (SR) structure
tubular fillers
out-of-plane
in-plane compression
Opis:
In this study, a semi-reentrant structure (SR) filled with different tubular structures, includ- ing tube, triangular and rectangle structures were designed. The tubular structures were perfectly assembled into semi-reentrant cells to avoid swaying in the semi-reentrant cell. The geometric relations and relative density for these structures were established. For the out-of-plane and in-plane compressions, SR filled tubular structures exhibited different de- formation patterns compared to those of SR or pure fillers. A constraint effect was found between the filler tubular and container SR. With fillers contained inside the SR structures, the plateau stresses for three conditions were all promoted compared to those of SR. The best out-of-plane compression resistance occurred in the SR filled rectangle which might be caused by larger interaction areas between the SR and rectangular structures. The (specific) energy absorption of the SR filled tube compressed out-of-plane was the largest. The peak and plateau stress of the SR filled triangle was the largest compared to other structures when compressed in plane due to stability of the triangle. It was found that the plateau stress, energy absorption and specific energy absorption of SR filled triangle was the largest, while that of SR filled rectangle was the lowest.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 233--244
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on Fretting Fatigue of Tungsten Carbide Coating Based on Strain Energy Density Methods
Autorzy:
Zeng, Xin
Wang, Xiaoxiao
Ping, Xuecheng
Wang, Renjie
Hu, Tao
Powiązania:
https://bibliotekanauki.pl/articles/2203727.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
WC coating
crack initiation
cracking angle
critical plane
life prediction
Opis:
The numerical solutions of stress and strain components on the critical plane of tungsten carbide coating were solved based on the critical plane method in three-dimensional coordinate system, and accordingly three strain energy density parameters (Smith-Watson-Topper, Nita-Ogatta-Kuwabara and Chen parameters) were determined to reveal the fretting fatigue characteristics of tungsten carbide coating. In order to predict the fretting fatigue life based on the strain energy density criterion, the expressions between the strain energy density parameter and the fretting fatigue life was obtained experimentally. After the comparison of the three strain energy parameters, it was found that all three parameters could accurately predict the crack initiation position, but only the Smith-Watson-Topper parameters could accurately predict the crack initiation angle. The effects of cyclic load, normal load and friction coefficient on fretting fatigue damage behaviors were discussed by using the Smith-Watson-Topper criterion. The results show that the fretting fatigue life decreases with the increase of cyclic load; an increase in the normal contact load will cause the Smith-Watson-Topper damage parameters more concentrated at the outer edge of the bridge foot; a decrease in the friction coefficient will increase the Smith-Watson-Topper damage parameters in the middle of the contact surface.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 21--30
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensor performance and cut-off wavelength tradeoffs of III-V focal plane arrays
Autorzy:
James, Jonathan Ch.
Haran, Terence L.
Lane, Sarah E.
Powiązania:
https://bibliotekanauki.pl/articles/2204205.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
infrared focal plane arrays
III-V semiconductor infrared detector technologies
infrared sensor performance modelling
infrared sensor design
mid-wave and longwave infrared sensors
Opis:
Infrared detector technologies engineered from III-V semiconductors such as strained-layer superlattice, quantum well infrared photodetectors, and quantum dot infrared photodetectors provide additional flexibility to engineer bandgap or spectral response cut-offs compared to the historical high-performance detector technology of mercury/cadmium/telluride. The choice of detector cut-off depends upon the sensing application for which the system engineer is attempting to maximize performance within an expected ensemble of operational scenarios that define objects or targets to be detected against specific environmental backgrounds and atmospheric conditions. Sensor performance is typically characterised via one or more metrics that can be modelled or measured experimentally. In this paper, the authors will explore the impact of detector cut-off wavelength with respect to different performance metrics such as noise equivalent temperature difference and expected target detection or identification ranges using analytical models developed for several representative sensing applications encompassing a variety of terrestrial atmospheric conditions in the mid-wave and long-wave infrared wavelength bands. The authors will also report on their review of recently published literature concerning the relationships between cut-off wavelength and the other detector performance characteristics such as quantum efficiency or dark current for a variety of detector technologies.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144570
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Steganography in Audio Files: COTS Software Analysis
Autorzy:
Marszałek, Piotr
Bilski, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/2201248.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steganography
audio
information hiding
steganalysis
encryption
compression
cybersecurity
cyberspace
embedding
information security
privacy
signal plane
non-signal plane
Opis:
The paper presents the analysis of the Commercial Off-The-Shelf (COTS) software regarding the ability to be used in audio steganography techniques. Such methods are a relatively new tool for hiding and transmitting crucial information, also being used by hackers. In the following work, the publicly available software dedicated to audio steganography is examined. The aim was to provide the general operating model of the information processing in the steganographic effort. The embedding method was analyzed for each application, providing interesting insights and allowing classifying the methods. The results prove that it is possible to detect the hidden message within the specific audio file and identify the technique that was used to create it. This may be exploited further during the hacking attack detection and prevention.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 1; 121--126
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unconventional building forms roofed with innovative structures arranged on regular surfaces with the negative Gaussian curvature
Autorzy:
Chrzanowska, Katarzyna
Abramczyk, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/27314404.pdf
Data publikacji:
2023
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
novel building form
complex shell roof
parametric modelling
nominally flat thin-walled folded sheeting
multi-plane elevation
Opis:
A novel method for shaping innovative building forms, roofed with diversified complex continuous and discontinuous folded structures composed of many transformed corrugated shell units, is presented in the paper. The units are defined on the basis of specific reference polyhedral networks and arranged on arbitrary reference surfaces characterized by the negative Gaussian curvature. The method is presented using several computer models of complex building structures with folded plane-walled elevations. The proposed method significantly supplements the previous method developed for modelling building free forms, roofed with shell structures arranged in conformity with surfaces having the positive Gaussian curvature. Some basic rules using parameterization and governing the creation of the multi-plane elevations, ribbed continuous and discontinuous roof shell structures, arranged in different unconventional and visually attractive patterns, were developed. The elaborated specific sets of division coefficients are taken as parameters for the designed building structures. These sets determine unconventional polyhedral networks, which are composed of several specific sets that allow to define a polygonal eaves network, a reference surface and, finally, individual shell units of the roof structures. The developed method is presented using the example of three novel forms defined by means of the appropriately selected diversified sets of values of the division coefficients. The elaborated new forms confirm the innovative nature of the achieved results. By imposing appropriate proportions between the values of these division coefficients, the developed method enables the creation of two different groups continuous and discontinuous complex shell roof structures.
Źródło:
Budownictwo i Architektura; 2023, 22, 3; 5--25
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Usage of Cold Forcing Method for a Gas Turbine Engine of Supersonic Transport
Autorzy:
Gutakovskis, Viktors
Gudakovskis, Vladimirs
Blumbergs, Ilmārs
Sarma, Elina
Powiązania:
https://bibliotekanauki.pl/articles/2201886.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
aviation
GTE
gas turbine engine
supersonic
plane
aircraft
Opis:
The article discusses the current state of development of supersonic transport, analyses the main limitation of the use of gas turbine engines when flying at high supersonic flight speeds, proposes a method for expanding the range of GTE limitations in these flight modes of the aircraft, using cold forcing of the engine, conducts an analytical study of the effectiveness of this approach, proposes one of the possible devices for the implementation of cold forcing, the efficiency of an engine with cold forcing is shown, which may be of significant interest for the application of cold forcing methods in gas turbine engines of supersonic transport.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 1; 267--273
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Method of Optimal Design for the Base Network in Structural Deformation Monitoring at Song Hinh Hydroelectricity, Vietnam
Metoda optymalnego projektowania sieci bazowej w monitoringu deformacji konstrukcji w elektrowni wodnej Song Hinh, Wietnam
Autorzy:
Pham, Quoc Khanh
Powiązania:
https://bibliotekanauki.pl/articles/2172078.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
plane control network
optimal design
residual level
engineering surveying
positional error
pozioma sieć kontrolna
optymalizacja projektu
poziom residuum
pomiary inżynierskie
błąd pozycji
Opis:
The article mentions a method of optimal design for the base network in horizontal displacement monitoring at hydroelectric works, based on the average residual level of the measured values. When the target function is the weakest positional error, the obtained result after optimizing is the unique plan that no depends on the designers and their experience. Thus, this is helpful for the production units because they no need to have experts in designing the network. Experiment for the base network of deformation monitoring at Song Hinh hydroelectricity shows that 44%, 50% and 60% of the initial measurement can be reduced when the average residual level is chosen 0.5, 0.4 and 0.3, respectively. The weakest position error of the network after optimizing is 2.4 mm, 2.5 mm and 2.6 mm, respectively, all are smaller than requirement ±3.6mm. This method is mainly applied for the side-angle network that was measured by total station, without considering the optimal design network in the priority direction.
W artykule przedstawiono metodę optymalnego projektowania sieci bazowej w monitoringu przemieszczeń poziomych elektrowni wodnych na podstawie średniego poziomu rezydualnego zmierzonych wartości. Gdy funkcją docelową jest najsłabszy błąd pozycjonowania, uzyskany wynik po optymalizacji jest unikalnym planem, który nie zależy od projektantów i ich doświadczenia. Jest to więc pomocne dla jednostek produkcyjnych, ponieważ nie potrzebują one ekspertów do projektowania sieci. Eksperyment dla podstawowej sieci monitorowania deformacji w elektrowni wodnej Song Hinh pokazuje, że 44%, 50% i 60% początkowego pomiaru można zmniejszyć, gdy średni poziom pozostałości zostanie wybrany odpowiednio 0,5, 0,4 i 0,3. Najsłabszy błąd pozycji sieci po optymalizacji wynosi odpowiednio 2,4 mm, 2,5 mm i 2,6 mm, wszystkie są mniejsze niż wymagane ±3,6 mm. Metodę tę stosuje się głównie dla sieci kątów bocznych, które zostały zmierzone przez tachimetr, bez uwzględnienia optymalnej sieci projektowej w kierunku pierwszeństwa.
Źródło:
Inżynieria Mineralna; 2022, 2; 13--20
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aeroacoustical study of the serrated ventilation dampers
Autorzy:
Kopania, Joanna Maria
Bogusławski, Grzegorz
Wójciak, Kamil
Gaj, Patryk
Powiązania:
https://bibliotekanauki.pl/articles/24201973.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
aeroacoustics
ventilation
plane damper
serrated edge
aeroakustyka
wentylacja
przepustnica jednopłaszczyznowa
krawędź ząbkowana
Opis:
The serrated ventilation dampers for regulation of airflow volume were tested. The computer fluid flow analysis was conducted using the Comsol program. The nature of the flow through the serrated ventilation damper was analyzed to identify the different turbulence regions formed on the airflow field. Additionally, the aerodynamical and acoustical parameters of these blades of ventilation dampers with different serrated trailing and/or leading-edge were studied. The aeroacoustic studies were done in the reverberation room. The sound power level and loss coefficient were determined for the studied models.
Źródło:
Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022313
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 265

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