by Muhammad Sajjad Hossain, M. A. Alim and Kazi H Kabir
Original Research
In this paper, we have studied MHD natural convection within trapezoidal cavity having circular block with uniformly heated bottom wall with inclination angles (ф). To investigate the effects of uniform heating with the circular block a Galerkin finite element method is studied and also used for solving the Navier-Stokes equations for different angles Φs. Here left and right walls are considered as cold and upper wall is considered as thermal insulated in a trapezoidal cavities. Rayleigh number (Ra) from 103 to 105, Hartmann number (Ha = 20) and Prandtl number (Pr) from 0.026 to 0.7 with various tilt angles Ф = 450, 300 and 00 (square) are concerned with the fluid. By different sets of governing equations along with the corresponding boundary conditions are used to set the physical problems. Results are shown in terms of streamlines, isotherms, heat flux and heat transfer rates for different Ra and Pr. It is seen that for different angles Φs conduction dominant region changes for different Pr when Ra increases. Local and average nusselt numbers are also used for heat transfer analysis for different irrespective Φs.
American Journal of Applied Mathematics and Statistics. 2016, 4(5), 161-168. DOI: 10.12691/ajams-4-5-4
Pub. Date: October 28, 2016
17166 Views3476 Downloads11 Likes
by Youhua Qian, Juan Wu and Yafei Zhang
Original Research
In this paper, we obtained the unique solution of the integral and coupled integral equation in the framework of fixed point theorem on partially ordered metric space. Our results unified some methods in studying the existence of unique solution for the integral equation. Moreover, all results are much more brief. In addition, the examples are given to illustrate the usability of the obtained results.
American Journal of Applied Mathematics and Statistics. 2016, 4(5), 154-160. DOI: 10.12691/ajams-4-5-3
Pub. Date: October 27, 2016
8251 Views2052 Downloads3 Likes
by Basanta Dhakal
Original Research
This study examines long run and short run causality of average expenditure of tourists by analyzing their length of stay and number of international visitors’ arrivals in Nepal by using co-integrating and causality analysis. The study has used annual tourism data of Nepal from the period of 1991 to 2014 provided by Ministry of Tourism and Civil Aviation. The co-integration analysis indicates that there is long run relationship among average expenditure per visitor, their length of stay and number of international tourist arrivals in Nepal. The result of vector error correction model indicates that coefficient of tourists’ expenditure elasticity with respect to average length of stay is more elastic as compared to coefficient of tourists’ expenditure elasticity with respect to number of international tourists’ arrival in Nepal. The results of Granger causality analysis, on the other hand, have depicted that there exists bidirectional causal relationship between expenditure per visitor and their average length of stay and unidirectional causality exists from average length of stay to number of international tourist.
American Journal of Applied Mathematics and Statistics. 2016, 4(5), 149-153. DOI: 10.12691/ajams-4-5-2
Pub. Date: October 12, 2016
16690 Views3626 Downloads8 Likes
by Chaido Dritsaki
Original Research
The low unemployment rate is one of the main targets of macroeconomic policy for each government. Forecasting unemployment rate is of great importance for each country so as the government can draw up strategies for fiscal policy. The aim of the paper is to find the most suitable model which is adjusted on unemployment rates of Greece using Box-Jenkins methodology and to examine the precision of forecasting on this model. Models’ estimation was made using the non-linear Maximum likelihood optimization methodology (maximum likelihood–ML), whereas covariance matrix is estimated with OPG method using the numerical optimization of Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm. Forecasting unemployment rate was made both with dynamic and static process using all criteria of forecasting measures.
American Journal of Applied Mathematics and Statistics. 2016, 4(5), 136-148. DOI: 10.12691/ajams-4-5-1
Pub. Date: September 29, 2016
47336 Views5890 Downloads