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991.
Gholamali Atefi Mohammad Reza Talaee 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(5):569-583
Analytical solution of the non-Fourier Axisymmetric temperature field within a finite hollow cylinder is investigated considering
the Cattaneo-Vernotte constitutive heat flux relation. The solution is found for the most general linear time-independent
boundary conditions. The material is assumed to be homogeneous and isotropic with temperature-independent thermal properties.
The standard method of separation of variables is used. The present solution can be reduced to special problems of interest
by choosing appropriate boundary condition parameters. The solution is applied for two special cases including constant heat
flux and the Gaussian distribution heating of a cylinder, and their respective non-Fourier thermal behavior is studied. 相似文献
992.
Mohammad O. Hamdan Ahmed Alawar Emad Elnajjar Waseem Siddique 《Heat and Mass Transfer》2011,47(12):1637-1642
The present study reports the effect of several operating parameters on the thermal performance of the vortex tube. The experimental
results indicate that the inlet pressure and the cold fraction are the most significant parameters influencing the vortex
tube performance. The experimental data point out that insulation has minimal effect on the vortex tube performance. The same
inlet pressure tests show that energy separation increases as number of inlet nozzle increases. 相似文献
993.
Mohammad Rezaiee-Pajand Mehrzad Sharifian Mehrdad Sharifian 《European Journal of Mechanics - A/Solids》2011,30(3):345-361
Up to now, some explicit approximate integration schemes based on exponential maps, for non-hardening material obeying Drucker–Prager’s criterion, have been presented. Two new exponential-based approximate formulations, for associative Drucker–Prager plasticity are developed in this article. Both are consistent and explicit algorithms. The linear isotropic and Prager’s kinematic hardening behavior are assumed. Furthermore, an accurate solution for the constitutive equations is derived. The accuracies of the suggested approximate algorithms are assessed by creating related iso-error maps. In addition, by using piecewise strain load histories, and calculating computation times, the robustness and efficiency of the formulations are demonstrated. 相似文献
994.
Mohammad Zarrin 《Archiv der Mathematik》2011,96(3):225-226
For any group G, let C(G){\mathcal{C}(G)} denote the set of centralizers of G. We say that a group G has n centralizers (G is a Cn{\mathcal{C}_n}-group) if |C(G)| = n{|\mathcal{C}(G)| = n}. In this note, we show that the derived length of a soluble Cn{\mathcal{C}_n}-group (not necessarily finite) is bounded by a function of n. 相似文献
995.
Mohammad Hassan Abbaspour Houshang Behravesh 《Rendiconti del Circolo Matematico di Palermo》2011,60(3):309-317
In Behravesh (J. Lond. Math. Soc. (2) 55:251–260, 1997), we gave algorithms to calculate c(G), q(G) and p(G) for a finite group G. In this paper we will show that in groups with two character degrees we may have c(G)=q(G)≠p(G). 相似文献
996.
We present a model for describing the growth of students’ understandings when reading a proof. The model is composed of two main paths. One is focused on becoming aware of the deductive structure of the proof, in other words, understanding the proof at a semantic level. Generalization, abstraction, and formalization are the most important transitions in this path. The other path focuses on the surface-level form of the proof, and the use of symbolic representations. At the end of this path, students understand how and why symbolic computations formally establish a claim, at a syntactic level. We make distinctions between states in the model and illustrate them with examples from early secondary students’ mathematical activity. We then apply the model to one student’s developing understanding in order to show how the model works in practice. We close with some suggestions for further research. 相似文献
997.
Abdul Moeed Mohammad 《International Journal of Mathematical Education in Science & Technology》2019,50(3):344-353
We explore students choice of using computer algebra systems (CAS) in problem-solving relative to their self-reported attitude towards learning mathematics with CAS. Our research design is a case study of nine Norwegian upper-secondary mathematics students with a wide range of attitude towards CAS. Our findings on routine problems indicate that (1) students use CAS whenever students perceive the problem as time-consuming regardless of their attitude towards CAS, and (2) students attitude affects their use of CAS whenever students perceive the problem as non-time-consuming. Norway, among other countries, has implemented CAS as an essential digital resource towards learning mathematics in upper-secondary school. Our discussion focuses on the implications of our findings have on local mathematics educators and national policy-makers. 相似文献
998.
Behzad Ramin Salehi Rad Mohammad Reza Nematollahi Nader 《Methodology and Computing in Applied Probability》2019,21(4):1045-1056
Methodology and Computing in Applied Probability - We consider a queueing system where some customers decide to simultaneously wait in two queues, rather than in a single queue, to receive their... 相似文献
999.
Ekechukwu Gerald K. Khishvand Mahdi Kuang Wendi Piri Mohammad Masalmeh Shehadeh 《Transport in Porous Media》2021,136(2):369-410
Transport in Porous Media - On the basis of a well-based model (Model I) developed in a previous work (Liu and Valkó in SPE J 2019. https://doi.org/10.2118/197049-PA ), in which a fractional... 相似文献
1000.
Nonlinear vibration mitigation of a flexible rotor shaft carrying a longitudinally dispositioned unbalanced rigid disc 总被引:1,自引:0,他引:1
Nonlinear Dynamics - This study is dedicated to investigate the nonlinear dynamics of a system composed of a flexible rotor shaft carrying a longitudinally dispositioned unbalanced rigid disc. The... 相似文献