This research is devoted to investigating the thermal buckling analysis behaviour of laminated composite plates subjected to uniform and non-uniform temperature fields by applying an analytical model based on a refined plate theory (RPT) with five unknown independent variables. The theory accounts for the parabolic distribution of the transverse shear strains through the plate thickness and satisfies the zero-traction boundary condition on the surface without using shear correction factors; hence a shear correction factor is not required. The governing differential equations and associated boundary conditions are derived by using the virtual work principle and solved via Navier-type analytical procedure to obtain critical buckling temperature. Results are presented for: uniform and linear cross-ply lamination with symmetry and antisymmetric stacking, simply supported boundary condition, different aspect ratio (a/b), various orthogonality ratio (E1/E2), varying ratios of coefficient of uniform and linear thermal expansion (α2⁄α1), uniform and linearly varying temperature thickness ratio (a/h) and numbers of layers on thermal buckling of the laminated plate. It can be concluded that this theory gives good results compared to other theories.
Phase change materials are known to be good in use in latent heat thermal energy storage (LHTES) systems, but one of their drawbacks is the slow melting and solidification processes. So that, in this work, enhancing heat transfer of phase change material is studied experimentally for in charging and discharging processes by the addition of high thermal conductive material such as copper in the form of brushes, which were added in both PCM and air sides. The additions of brushes have been carried out with different void fractions (97%, 94% and 90%) and the effect of four different air velocities was tested. The results indicate that the minimum brush void fraction gave the maximum heat transfer in PCM and reduced the time
... Show MoreThe study aims to make an in-depth analysis and the financial account components in the Iraqi balance of payments because it reflects the economic center of the country towards outside world, it also helps in making decision about monetary and financial policies, finance and foreign Trade the importance of FDI for Iraq lies as an important sources as wells provides advanced technology and job chances, It also avoids the country negative effects of borrowing processes from abroad . for analyzing direct and indirect foreign investment on the balance of payments and financial account in a period between (2003 to 2015), a community and research sample have been selected, presented in CBI/ Balance of payments. Department,
... Show MoreThis study aims to the little impact of accounting financial performance (AFP) analysis on the money market in the Iraqi economy. Potentially limiting future market activity could be international risks and obstacles, which in turn could cause issues and crises (Shah & Jan, 2014; Bakhtiyarovich, 2020). The study concept was inspired by the recognition that there must be communication between the importance of the AFP analysis of the Iraqi securities market and the country’s financial and economic institutions. The sample of the study included ten Iraqi banks listed in the Iraq Stock Exchange (ISE) for the period 2010–2020. The three mathematical models included in the statistical analysis served as the basis for projectin
... Show MoreThe external shocks are one of the phenomena that the Iraqi economy is exposed to over a period of time. It is referred to as changes and events that come from outside the economic system and extends to many economic variables. However, foreign direct investment may be severely affected due to the extreme sensitivity to changes and local and international developments. This type of trauma and its characteristics to help manage and cope with external shocks, and in order to avoid the standard problems experienced by some models of simple linear regression, multi-linear regression models were used with variables Scientific and other dummy variables .
The study foun
... Show MoreA numerical simulation is made on the thermal lensing effect in an laser diode end-pumped Nd:YAG laser rod. Based on finite element method (FEM), the laser rod temperature distribution is calculated and the focal length is deduced for a Gaussian and super-Gaussian pump beam profiles.
At the pump power of 20W, the highest temperature located at the center of end-pumped face was 345K, and the thermal lens focal length was 81.4mm along the x-z axis.
The results indicate that the thermal lensing effect sensitively depend on the pump power, waist radius of the pump beam and the pump distribution in a laser rod geometry.
This paper presents thermal characteristics analysis of a modified Closed Wet Cooling Tower (CWCT) based on heat and mass transfer principles to improve the performance of this tower in Iraq. A prototype of CWCT optimized by added packing was designed, manufactured and tested for cooling capacity of 9 kW. Experiments are conducted to explore the effects of various operational and conformational parameters on the thermal performance. In the test section, spray water temperature and both dry bulb temperature and relative humidity of the air measured at intermediate points of the heat exchanger and packing. Heat exchangers consist of four rows and eight columns for an inline tubes arrangement and six rows and five columns f
... Show MoreDynamic Thermal Management (DTM) emerged as a solution to address the reliability challenges with thermal hotspots and unbalanced temperatures. DTM efficiency is highly affected by the accuracy of the temperature information presented to the DTM manager. This work aims to investigate the effect of inaccuracy caused by the deep sub-micron (DSM) noise during the transmission of temperature information to the manager on DTM efficiency. A simulation framework has been developed and results show up to 38% DTM performance degradation and 18% unattended cycles in emergency temperature under DSM noise. The finding highlights the importance of further research in providing reliable on-chip data transmission in DTM application.