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Wyświetlanie 1-15 z 11364
Tytuł:
Applicability of artificial intelligence in smart healthcare systems for automatic detection of Parkinson’s Disease
Autorzy:
Pallathadka, Harikumar
Padminivalli V., S.J.R.K.
Vasavi, M.
Nancy, P.
Naved, Mohd
Kumar, Harish
Ray, Samrat
Powiązania:
https://bibliotekanauki.pl/articles/38709253.pdf
Data publikacji:
2024
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
Parkinson’s disease
detection
machine learning
relief algorithm
LDA algorithm
SVM-RBF
accuracy
sensitivity
specificity
choroba Parkinsona
wykrywanie
nauczanie maszynowe
algorytm ulgi
Algorytm LDA
dokładność
wrażliwość
specyficzność
Opis:
Parkinson’s disease is associated with memory loss, anxiety, and depression in the brain. Problems such as poor balance and difficulty during walking can be observed in addition to symptoms of impaired posture and rigidity. The field dedicated to making computers capable of learning autonomously, without having to be explicitly programmed, is known as machine learning. An approach to the diagnosis of Parkinson’s disease, which is based on artificial intelligence, is discussed in this article. The input for this system is provided through photographic examples of Parkinson’s disease patient handwriting. Received photos are preprocessed using the relief feature option to begin the process. This is helpful in the process of selecting characteristics for the identification of Parkinson’s disease. After that, the linear discriminant analysis (LDA) algorithm is employed to reduce the dimensions, bringing down the total number of dimensions that are present in the input data. The photos are then classified via radial basis function-support vector machine (SVM-RBF), k-nearest neighbors (KNN), and naive Bayes algorithms, respectively.
Źródło:
Computer Assisted Methods in Engineering and Science; 2024, 31, 2; 175-185
2299-3649
Pojawia się w:
Computer Assisted Methods in Engineering and Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cyclooxygenase-2 – characteristics, functions and possible use as a biomarker in human and animal oncology – A review
Autorzy:
Szweda, M.
Rychlik, A.
Babińska, I.
Kaczmar, E.
Szweda, W.
Makowska, K.
Powiązania:
https://bibliotekanauki.pl/articles/53370806.pdf
Data publikacji:
2024
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Opis:
Neoplastic diseases are currently one of the most common causes of mortality in both animals and humans. Therefore, much of the recent research focuses on the search for biomarkers to enable qualitative and temporal improvement in the detectability as well as prognostic and predictive assessments in patients suffering from neoplastic diseases. One such biomarker seems to be cyclooxygenase-2 (COX-2), also known as prostaglandin G/H synthase (PTGS). The wide dissemination of COX isoforms and prostanoids synthesized with their involvement in the tissues indicates the significant role they serve in the regulation of the functioning of several organs and systems, particularly the gastrointestinal, nervous, circulatory, reproductive, urinary and respiratory systems. Until recently, COX-2 has only been associated with the response to stress and inflammation initiators. It is currently known that its expression increases significantly in the course of numerous pathological processes that involve inflammation, pain or fever. Results obtained during previous studies demonstrated a significant increase in COX-2 expression in several types and subtypes of neoplasms in humans and animals, particularly in dogs and cats, the two animal species that have been studied the most frequently. COX-2 has not been adopted yet as one of the biomarkers for routine oncological diagnostics, which indicates the possibility for wider use of the assessment of its expression in the diagnostics and therapy of neoplasms in humans and animals. It may therefore be possible to use an assessment of COX-2 overexpression to improve cancer diagnostics and therapy and for prognostic and/or predictive purposes.
Źródło:
Journal of Elementology; 2024, 29, 1; 175-191
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of a herbicide and biostimulants on the content and uptake of selected micronutrients by edible potato tubers
Autorzy:
Zarzecka, K.
Ginter, A.
Gugała, M.
Mystkowska, I.
Powiązania:
https://bibliotekanauki.pl/articles/53592018.pdf
Data publikacji:
2024
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Opis:
The research material consisted of table potato tubers harvested in a three-year field experiment carried out at the Agricultural Experimental Station in Zawady of University of Siedlce in 2018-2020. It was set up in triplicate on tawny soil. The main factor were two mid-early potato cultivars, Oberon and Malaga, and the sub-plot factor included five options of treatment with a herbicide and biostimulants: 1. control, 2. the herbicide Avatar 293 ZC, 3. the herbicide Avatar 293 ZC and the biostimulant PlonoStart, 4. the herbicide Avatar 293 ZC and the biostimulant Aminiolant, 5. the herbicide Avatar 293 ZC and the biostimulant Agro-Sorb Folium. The objective of the study was to determine the impact of biostimulant and herbicide applications on the content and uptake of selected micronutrients by potato tubers. Manganese (Mn) and copper (Cu) contents were determined in tuber dry matter using an ICP-OES spectrometer (Perkin Elmer, Optima 8300, USA). Higher Cu content was found in cv. Malaga tubers compared with Oberon, while greater uptake of both elements (Mn, Cu) with tuber yield was determined in cv. Oberon due to its higher yield. An application of biostimulants increased the Cu content as well as Mn and Cu uptake compared with control tubers. The most beneficial effect was produced by using the biostimulant Agro-Sorb Folium. Manganese and copper were significantly affected by the weather during the study years. It should be added that the agricultural sector has recently become increasingly aware of the environmental impact of the measures used, and in this context, biostimulants are gaining popularity to improve the quality of crops, minimizing the negative impact on the environment.
Źródło:
Journal of Elementology; 2024, 29, 1; 57-71
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of a vaccination program on physicochemical characteristics, meat texture, and metric traits of the digestive tract and leg bones of broilers
Autorzy:
Wegner, M.
Kokoszyński, D.
Kotowicz, M.
Żochowska-Kujawska, J.
Tarasiuk, K.
Jankowiak, H.
Bujko, J.
Powiązania:
https://bibliotekanauki.pl/articles/53355597.pdf
Data publikacji:
2024
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Opis:
Various immunoprophylaxis programs aimed at protecting chickens from different pathogens and reducing production losses due to mortality or disease are increasingly important in broiler rearing. The aim of this study was to compare the effect of two different commercial prophylactic vaccination programs (H1 vs. H2), using vaccines against Marek’s disease (MD), infectious bursal disease (IBD), infectious bronchitis virus (IBV) and avian metapneumovirus (AMPV) on the chemical composition, physicochemical properties, meat texture, and biometric characteristics of the digestive system and leg bones of Ross 308 broiler chickens. The study material consisted of 20 carcasses (10 male and 10 female) of 42-day-old broiler chickens. After determining the weight of the eviscerated carcass (H1 – 1822.8±212.4; H2 – 2295.6±275.6), the breast and leg muscles were cut out of the dissected elements of the carcass, followed by the measurements of pH24, L*, a*, b* color attributes, electrical conductivity (EC24) and cooking loss. The basic chemical composition and texture characteristics were determined. Measurements of the femur and tibia were taken after separating the meat from the bone. Measurements of the lengths and diameters of the individual intestinal segments were also carried out. The H2 vaccination program had a significant positive effect on the carcass weight of 42-day-old broilers. Chickens subjected to the H1 vaccination program were characterized by significantly lower water and collagen content, pH24, and meat tenderness (higher WB shear force) in the breast, as well as significantly higher protein content in the breast and leg muscles, and a lower percentage of fat in the leg muscles compared to chickens subjected to the H2 vaccination program The dimensions of femur and tibia bones in 42-day-old broiler chickens administered vaccines according to the H2 vaccination program were significantly higher than in chickens on the H1 vaccination program.
Źródło:
Journal of Elementology; 2024, 29, 2; 401-417
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of cadmium and lead on living organisms – transport, accumulation, metabolism
Autorzy:
Bąkowski, M.
Winiarska-Mieczan, A.
Kwiecień, M.
Krusiński, R.
Jachimowicz-Rogowska, K.
Twarużek, M.
Grobelska, D.
Powiązania:
https://bibliotekanauki.pl/articles/53376672.pdf
Data publikacji:
2024
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Opis:
Heavy metals are metals and non-metals with molecular weights exceeding 20 and specific gravity above 5. The heavy metal cycle in the environment is linked to the food chain: soil – plant – animal – human. The transfer of metals to the higher link results in a cumulative increase in their content. Pollution with heavy metals has become a severe threat to the environment and food safety due to the rapid development of agriculture and industry and disturbances in the natural ecosystem induced by the enormous growth of the global population. Major sources of heavy metals in soil are bedrock, industrial and transport emissions, municipal management, and agriculture. Three main reasons for the toxicity of metals were found to be: participation of metals in enhancing the production of ROS (Reactive Oxygen Species) and modification of the activity of the antioxidant system, ability to react directly with proteins, resulting from the affinity between metals and thiol, histidine and carboxyl groups and leading to the attachment of metal ions to active sites of enzymes, structural elements of cells and proteins involved in cell transport, and replacement of elements necessary for metabolism, e.g. calcium in bones or iron in erythrocytes with metals, which leads to damage and changes in their structure and metabolism. The key solution towards decreasing the content of Cd and Pb in food is to limit or prevent their initial absorption by plants used for food or animal feed. However, due to the complexity of interactions between soil chemistry, varieties and species of plants and agronomic practices, additional research is needed.
Źródło:
Journal of Elementology; 2024, 29, 1; 311-328
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A bioinspired optimization strategy: to minimize the travel segment of the nozzle to accelerate the fused deposition modeling process
Autorzy:
Sridhar, Sundarraj
Aditya, K.
Venkatraman, Ramamoorthi
Venkatesan, M.
Powiązania:
https://bibliotekanauki.pl/articles/27311459.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
additive manufacturing
fused deposition modeling
extruder path
ant colony optimization
build time
produkcja dodatkowa
modelowanie osadzania stopionego
ścieżka wytłaczarki
optymalizacja kolonii mrówek
czas budowy
Opis:
The fused deposition modeling process of digital printing uses a layer-by-layer approach to form a three-dimensional structure. Digital printing takes more time to fabricate a 3D model, and the speed varies depending on the type of 3D printer, material, geometric complexity, and process parameters. A shorter path for the extruder can speed up the printing process. However, the time taken for the extruder during printing (deposition) cannot be reduced, but the time taken for the extruder travel (idle move) can be reduced. In this study, the idle travel of the nozzle is optimized using a bioinspired technique called "ant colony optimization" (ACO) by reducing the travel transitions. The ACO algorithm determines the shortest path of the nozzle to reduce travel and generates the tool paths as G-codes. The proposed method’s G-code is implemented and compared with the G-code generated by the commercial slicer, Cura, in terms of build time. Experiments corroborate this finding: the G-code generated by the ACO algorithm accelerates the FDM process by reducing the travel movements of the nozzle, hence reducing the part build time (printing time) and increasing the strength of the printed object.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 4; art. no. e146236
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Diminutive Wide-band MIMO Antenna with Frequency Agile Features for 4G and 5G Diverse Wireless Applications
Autorzy:
Mudda, Shivleela
K M, Gayathri
Mallikarjun, M
Powiązania:
https://bibliotekanauki.pl/articles/27311969.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Diversity gain (DG)
Defective ground structure (DGS)
Fractional bandwidth (FBW)
ITU (International Telecommunication Union)
INSAT
Frequency Reconfigurable antenna (FRA)
Multiple input multiple output (MIMO)
mutual coupling
isolation
5G
Envelope correlation coefficient (ECC)
Opis:
This paper demonstrates a low-profile, wide-band, two-element, frequency-reconfigurable MIMO antenna that is suitable for diverse wireless applications of 4G and 5G such as WLAN/Bluetooth (2.4–2.5 GHz), WLAN (2.4–2.484 GHz, 5.15– 5.35 GHz, and 5.725–5.825 GHz), WiMAX (3.3–3.69 GHz and 5.25–5.85 GHz), Sub6GHz band proposed for 5G (3.4–3.6 GHz, 3.6-3.8GHz and 4.4–4.99 GHz), INSAT and satellite X-band(6 to 9.6 GHz). Proposed MIMO favour effortless switching between multiple bands ranging from 2.2 to 9.4 GHz without causing any interference. Both antenna elements in a MIMO array are made up of a single module comprised of a slot-loaded patch and a defective structured ground. Two PIN diodes are placed in the preset position of the ground defect to achieve frequencyreconfigurable qualities. The suggested MIMO antenna has a size of 62 ×25 ×1.5 mm3. Previous reconfigurable MIMO designs improved isolation using a meander line resonator, faulty ground structures, or self-isolation approaches. To attain the isolation requirements of modern devices, stub approach is introduced in proposed design. Without use of stub, simulated isolation is 15dB. The addition of a stub improved isolation even more. At six resonances, measured isolation is greater than 18 dB, the computed correlation coefficient is below 0.0065, and diversity gain is over 9.8 dB.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 3; 439--448
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new form of neurotherapy for a patient with anxiety disorder and anomic aphasia after neurosurgery for a ruptured brain aneurysm post-COVID-19
Autorzy:
Morga, R.
Góral-Półrola, J.
Goździewska, M.
Krupa, K.
Pąchalska, M.
Powiązania:
https://bibliotekanauki.pl/articles/28762642.pdf
Data publikacji:
2023
Wydawca:
Instytut Medycyny Wsi
Źródło:
Annals of Agricultural and Environmental Medicine; 2023, 30, 2; 331-341
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A pedological study attempting to combine soil taxonomy and WRB classification systems
Autorzy:
Zayed, Adel M.A.
Abdel Ghaffar, Mamdouh K.
Ali, Faiza S.
Ewida, Esmail H.
Powiązania:
https://bibliotekanauki.pl/articles/27312660.pdf
Data publikacji:
2023
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
North-East Nile Delta
pedological study
physiographic units
soil classification
Opis:
The study area is located in the North-Eastern part of the Nile Delta, northern of Ismailia canal and western Suez Canal. It comprises an area of about 3,058.8 km 2 (728,285.38 feddans). This work aims to identify the main physiographic units and its features, as well as emphasise the importance of combining soil taxonomy (2014) and WRB classification (2022) systems. Two main physiographic units were distinguished in the study area according to the previous studies, interpretation of satellite image and digital elevation model (DEM) as well as field observations; the first consists of fluvio-marine flats and the second river terraces which include the fluvial and deltaic origin. According to field morphological descriptions as well as chemical and physical analyses, representative profiles are classified by using both Soil Taxonomy and WRB systems. The current study is the third manuscript to emphasise the importance of using both systems together in order to obtain maximum possible characteristics of the earth. Below are examples that illustrate this importance. Soils of profile No. 4 which represent the fluvio-marine soils are classified according to soil taxonomy as follows: Typical Haplosalids, fine silty, mixed, thermic. While these soils are classified according to WRB as follows: Fluvic Sodic Solonchaks (Siltic/Loamy/Clayic, Chloridic, Evapocrustic, Ochric, Hypersalic). Soils of gypsiferous which represent soils of profile No. 6 are classified according to Soil Taxonomy as: Gypsic Aquisalids, loamy over sandy, mixed, thermic, whereas the application of the WRB system reveals the following: Fluvic Calcic Gypsic Sodic Gleyic Solonchaks (Loamic, Chloridic, Hypersalic).
Źródło:
Journal of Water and Land Development; 2023, 57; 197--203
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review of tuberculosis and parasitic disease co-infection in ungulates, with regard to the potential threat to European bison (Bison bonasus)
Autorzy:
Gałązka, M.
Didkowska, A.
Anusz, K.
Pyziel-Serafin, A.
Powiązania:
https://bibliotekanauki.pl/articles/16647526.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
bovine tuberculosis
co-infection
Fasciola hepatica
helminths
Mycobacterium bovis
Mycobacterium caprae
parasites
Opis:
Bovine tuberculosis (BTB) is a dangerous zoonosis which presents a serious problem for endangered species such as European bison (Bison bonasus). Little is known about the influence of parasitic co-infections on the course and diagnosis of tuberculosis in animals. The best known co-infection in cattle is Fasciola hepatica and Mycobacterium bovis. The aim of this study was to review the most recent literature regarding tuberculosis and parasite co-infection in ungulates and relate the results to European bison. Our findings indicate that any comprehensive diagnosis of BTB should include parasitological monitoring, and the possible impact of such invasions on cellular response-based tuberculosis tests should be taken into account. The diagnosis of BTB is complex, as is its pathogenesis, and parasitic infestations can have a significant impact on both. This should be taken into account during further research and monitoring of tuberculosis in European bison.
Źródło:
Polish Journal of Veterinary Sciences; 2023, 26, 1; 155-161
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on the Influence of Reinforcement Volume on AA5083/(SiC-Gr) Hybrid Surface Composite Developed by Friction Stir Processing
Autorzy:
Bharti, Shalok
Ghetiya, Nilesh D.
Patel, Kaushik M.
Saxena, Kuldeep K.
Powiązania:
https://bibliotekanauki.pl/articles/27765096.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
surface composites
multi-pass
Friction Stir Processing
reinforcement
hybrid composite
Opis:
In this study, a hybrid surface composite of AA5083/SiC-Gr was produced by Friction Stir Processing (FSP). Reinforcement material each in 50:50 proportion was filled in the base matrix using holes method. Three different hybrid reinforcement volumes of 301.6 mm3, 452.4 mm3, and 603.2 mm3 were prepared for surface composite. Optical and Scanning Electron Microscopy was used to check the quality of the prepared surface composite and homogeneous distribution of reinforcement was observed in the images. It was observed that due to better uniform distribution of reinforcement particles during 3 pass FSP, specimens with 301.6 mm3 reinforcement volume showed enhanced microhardness and wear properties in comparison with the other specimens.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 625--629
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Efficient Hybrid Classifier Model for Customer Churn Prediction
Autorzy:
Anitha, M. A.
Sherly, K. K.
Powiązania:
https://bibliotekanauki.pl/articles/2200701.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
customer churn prediction
bag of learners
ANN
SVM
regression
associative classifier
Apriori Algorithm
Opis:
Customer churn prediction is used to retain customers at the highest risk of churn by proactively engaging with them. Many machine learning-based data mining approaches have been previously used to predict client churn. Although, single model classifiers increase the scattering of prediction with a low model performance which degrades reliability of the model. Hence, Bag of learners based Classification is used in which learners with high performance are selected to estimate wrongly and correctly classified instances thereby increasing the robustness of model performance. Furthermore, loss of interpretability in the model during prediction leads to insufficient prediction accuracy. Hence, an Associative classifier with Apriori Algorithm is introduced as a booster that integrates classification and association rule mining to build a strong classification model in which frequent items are obtained using Apriori Algorithm. Also, accurate prediction is provided by testing wrongly classified instances from the bagging phase using generated rules in an associative classifier. The proposed models are then simulated in Python platform and the results achieved high accuracy, ROC score, precision, specificity, F-measure, and recall.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 1; 11--18
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An efficient microgrid model based on Markov fuzzy demand-side management
Autorzy:
Jabash Samuel, G. K.
Sivagama Sundari, M. S.
Bhavani, R.
Jasmine Gnanamalar, A.
Powiązania:
https://bibliotekanauki.pl/articles/27311444.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
smart grid
fuzzy Markov decision process
power scheduling
operating cost
nonlinear model predictive control
inteligentna sieć
planowanie mocy
koszt operacyjny
proces decyzyjny Markowa rozmyty
regulator predykcyjny nieliniowego modelu
Opis:
Today’s electricity management mainly focuses on smart grid implementation for better power utilization. Supply-demand balancing, and high operating costs are still considered the most challenging factors in the smart grid. To overcome this drawback, a Markov fuzzy real-time demand-side manager (MARKOV FRDSM) is proposed to reduce the operating cost of the smart grid system and maintain a supply-demand balance in an uncertain environment. In addition, a non-linear model predictive controller (NMPC) is designed to give a global solution to the non-linear optimization problem with real-time requirements based on the uncertainties over the forecasted load demands and current load status. The proposed MARKOV FRDSM provides a faster scale power allocation concerning fuzzy optimization and deals with uncertainties and imprecision. The implemented results show the proposed MARKOV FRDSM model reduces the cost of operation of the microgrid by 1.95%, 1.16%, and 1.09% than the existing method such as differential evolution and real coded genetic algorithm and maintains the supply-demand balance in the microgrid.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 3; art. no. e145569
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An experimental study of forced vibration on natural convection between closed ended concentric and eccentric annular of horizontal cylinder
Autorzy:
Khudhair, Baydaa K.
Saleh, Adel M.
Ekaid, Ali L.
Powiązania:
https://bibliotekanauki.pl/articles/2203644.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
cylindrical annulus
concentric
vertically eccentric
vibration inner cylinder
drgania wymuszone
cylinder
drgania
Opis:
An experimental study has been done into the effects of vertical mechanical vibrating, vertical eccentricity, and the Rayleigh number on natural convection heat transferring out of a horizontally enclosed, ending cylindrical annulus with a radius rate of 2.6 and an aspect ratio of (2:1). The annulus produced between two concentric and vertically eccentric circular cylinders is positioned horizontally, and its internal wall is uniformly heated while isothermally cooling the external wall. The range of present conditions for Rayleigh number is 5×10^4 ≤ Ra≤ 6.48×10^6, and Pr = 0.703, the frequency of vibration is 0 ≤ f ≤ 20Hz; and the amplitude is b mm), with possible exclusion of the highest positive and negative eccentricities. Plots of the average Nusselt number variation against the Rayleigh number showed a significant increase in negative vertical eccentricity. It was found that the average Nusselt decreased as the internal cylinder changed its location vertically from negative to positive through the center, which is normally a desirable effect, but has no advantage over the concentric on the positive side. The Rayleigh number was found to be relatively sensitive to eccentricity. However, an increase of Rayleigh number leads to a nearly proportional increase in the average Nusselt number and a smaller yet still substantial increase in positive eccentricity. This study concluded that the vibration under the current experimental setup significantly affects the concentric position of the internal cylinder, whether the effect is positive or negative. The vibrational average Nusselt number increased in varying proportions, depending on the location of the heated inner cylinder.
Źródło:
Diagnostyka; 2023, 24, 2; art. no. 20230212
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 11364

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