Enerji Sistemleri Mühendisliği Bölümühttps://hdl.handle.net/11494/2712024-03-29T14:25:25Z2024-03-29T14:25:25ZIsı transferinde ısı kayıplarının yapay sinir ağları yöntemi ile incelenmesiÇırak, BekirKorcak, Sabithttps://hdl.handle.net/11494/41662022-08-25T12:09:59Z2017-01-01T00:00:00ZIsı transferinde ısı kayıplarının yapay sinir ağları yöntemi ile incelenmesi
Çırak, Bekir; Korcak, Sabit
Bu çalışmada binalarda ısıtma için kullanılan kalorifer borularının yalıtımlı ve yalıtımsız durumları için iki
ayrı yapay sinir ağı (YSA) modeli ve bina duvarlarının yalıtımlı ve yalıtımsız durumları için iki ayrı YSA modeli
olmak üzere toplamda 4 ayrı model kullanılmıştır. Bu durumlar için tasarlanan YSA modellerinde 3 katmanlı ileri
beslemeli ve geri yayılımlı bir model şekli tercih edilmiştir. Gizli katmanda sigmoid transfer fonksiyonu, çıkış
katmanında ise doğrusal transfer fonksiyonu kullanılmıştır. YSA ağ topolojisi olarak geri yayılımlı YSA topolojisi
tercih edilmiş ve veriler normalize edilerek ağa sunulmuştur. Ağdan elde edilen sıcaklık değerleri gerçekte
ölçülen sıcaklık değerleri ile mukayese edilmiş ve sonuçların birbirlerine çok yakın ve yeterli hassasiyette olduğu
görülmüştür. Bu şekilde 4 farklı iç model için YSA metodunun kullanımı, modellerin açıklayıcılık ve tahmin etme
gücünü artırmıştır.; In this study, two artificial neural network model and two separate neural networks for insulated and
uninsulated case of building walls insulated and uninsulated state of the heating pipes used for heating in studies in
the building here (ANN) a total of 4 separate models are used to make the model. In this case, 3-layer feed-forward
and back propagation neural network model in a model designed to have preferred shape. Sigmoid transfer function
in the hidden layer and the output layer is used in the linear transfer function. ANN network topology is preferred as
backpropagation neural network topology and data are presented normalized to the network. The temperature value
is obtained from the network is compared with the actually measured temperature values are compared and the
results were found to be very close to each other and the results were found to be sensitive enough. In this way, the
use of artificial neural network method to four different internal models forecast increased the explanatory power
of the model and predict
2017-01-01T00:00:00ZAn investigation of magnetoresistivity properties of an Y3Ba5Cu8Oy bulk superconductorKütük, SezaiBolat, SüleymanTerzioğlu, CabirAltıntaş S.P.https://hdl.handle.net/11494/34532021-09-22T08:42:56Z2015-01-01T00:00:00ZAn investigation of magnetoresistivity properties of an Y3Ba5Cu8Oy bulk superconductor
Kütük, Sezai; Bolat, Süleyman; Terzioğlu, Cabir; Altıntaş S.P.
A bulk ceramic superconducting sample was fabricated using the standard solid state reaction (SSR) method in the stoichiometric ratio of Y:Ba:Cu:O (3:5:8). The electrical and microstructural properties of the sample were investigated by means of magnetoresistivity (R-T) and micrograph measurements, respectively. Critical temperatures (T-c) such as onset and offset, irreversibility magnetic field (H-irr), upper critical magnetic field (H-c2), and activation energy (U-0) were determined from the R-T under various values of applied magnetic field. The findings obtained were compared with a standard Y:Ba:Cu:O(1:2:3) superconducting sample fabricated by the SSR method. T-c(onset) was 95.83 K for the Y358 sample and 94.86 K for the Y123 sample without the magnetic field. T-c(offset) decreased from 92.87 to 74.08 K for the Y358 sample and from 82.83 to 32.44 K for the Y123 sample when the magnetic field ranged from 0 to 5 T. U-0 values of Y358 and Y123 samples without the magnetic field were respectively 1.1486 and 0.3166 eV. These results indicate that the Y358 sample could provide significant benefits for high temperature superconductivity applications in future.
This work was supported by a grant (contract no: 2010.111.001.1) from the Scientific Research Projects Coordination Unit of Karadeniz Technical University.
2015-01-01T00:00:00ZInvestigation of superconducting and normal-state properties of the filled-skutterudite system PrPt4Ge12-xSbxJeon, InhoHuang, KevinYazıcı, DuyguKanchanavatee, NoraveeWhite, B. D.Ho, Pei-ChunJang, SooyoungPouse, NaveenMaple, M. Brianhttps://hdl.handle.net/11494/34142021-09-10T07:47:37Z2016-01-01T00:00:00ZInvestigation of superconducting and normal-state properties of the filled-skutterudite system PrPt4Ge12-xSbx
Jeon, Inho; Huang, Kevin; Yazıcı, Duygu; Kanchanavatee, Noravee; White, B. D.; Ho, Pei-Chun; Jang, Sooyoung; Pouse, Naveen; Maple, M. Brian
We report a study of the superconducting and normal-state properties of the filled-skutterudite system PrPt4Ge12-xSbx. Polycrystalline samples with Sb concentrations up to x = 5 were synthesized and investigated by means of x-ray diffraction, electrical resistivity, magnetic susceptibility, and specific heat measurements. We observed a suppression of superconductivity with increasing Sb substitution up to x = 4, above which no signature of superconductivity was observed down to 140 mK. The Sommerfeld coefficient, gamma, of superconducting specimens decreases with increasing x up to x = 3, suggesting that superconductivity may depend on the density of electronic states in this system. The specific heat for x = 0.5 exhibits an exponential temperature dependence in the superconducting state, reminiscent of a nodeless superconducting energy gap. We observed evidence for a weak "rattling" mode associated with the Pr ions, characterized by an Einstein temperature Theta(E) similar to 60 K for 0 <= x <= 5; however, the rattling mode may not play any role in suppressing superconductivity.
This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Grant No. DE-FG02-04-ER46105 (characterization and physical properties measurements), and the National Science Foundation under Grant No. DMR 1206553 (low-temperature measurements). Helpful discussions with S. Ran are gratefully acknowledged.
2016-01-01T00:00:00ZStructure, magnetization, specific heat, and microwave properties of KxFe2-ySe2Yazıcı, DuyguBaşaran, Ali CemilRamirez, Juan GabrielSchuller, Ivan K.Maple, M. Brianhttps://hdl.handle.net/11494/32752021-07-07T10:32:17Z2016-01-01T00:00:00ZStructure, magnetization, specific heat, and microwave properties of KxFe2-ySe2
Yazıcı, Duygu; Başaran, Ali Cemil; Ramirez, Juan Gabriel; Schuller, Ivan K.; Maple, M. Brian
Temperature-dependent magnetization, specific heat, and magnetic field modulated microwave spectroscopy (MFMMS) measurements were performed on single crystals of KxFe2-ySe2. Magnetization measurements yield a superconducting transition temperature (T-c) of similar to 30 K, with a diamagnetic shielding fraction of nearly 90%. Specific heat measurements revealed a 'jump' at T-c, Delta C/T vertical bar T-c, of about 6.8 +/- 1 mJ mol(-1) K-2, consistent with bulk superconductivity in KxFe2-ySe2. Moreover, MFMMS measurements detect the superconductivity of KxFe2-ySe2. with a peak with an onset at T-c(mu) similar to 28 K, close to the values of T-c determined from the magnetization and specific heat measurements. The presence and the shape of the low temperature MFMMS signal could be ascribed to a complex dissipation mechanism and percolative superconductivity.
2016-01-01T00:00:00Z