In this study, an analysis of fiber reinforced, symmetrically laminated composite plates containing CIRCULAR HOLES has been carried out. First, the stress state of a layer in a laminated plate is studied. After obtaining the stress state for each layer due to the uniaxial loading of a plate, the stress concentrations around a CIRCULAR hole are studied. A number of diagrams are drawn to show the stress concentrations around a hole for layers having different oriented fibers using different material pairs with different E1/E2 ratios (ratio of elasticity modulus of fiber direction to that of transverse direction). Graphs are given for various E1/E2 values for the circumferential stress values around the hole versus angular location of points for two different fiber orientation angles. Second, the failure of the laminated composite plate is studied. To determine the “first–ply failure” of a laminated plate, Tsai-Hill failure criterion is employed to find minimum bearing circumferential stresses and where they occur as a function of the fiber orientation angle.

In the operation of water distribution networks in cities, leakage from pipes always causes problems for human health and for the environment. Leakage openings in pipes may exist in different shapes. CIRCULAR HOLES are common in corroded and punched pipes. In the leakage studies, the area of these openings is usually assumed to be fixed and the leakage exponent is about 0.5. In this study, an analytical equation has been presented with two purposes. First, Examining the changes in the leak area and leakage exponent of CIRCULAR HOLES. Second, providing an equation that contains more parameters than the general leakage equations. By using such an equation, the accuracy of leakage estimation is increased due to the direct involvement of the effective parameters. Also, for the possibility of modeling different leakage equations, including the present equation, a new hydraulic analysis model has been developed. This model tries to improve leakage modeling by including more capabilities than the existing hydraulic analysis models. Results showed that the leak area in CIRCULAR HOLES is not fixed and changes due to different parameters. Comparison of the present equation and the orifice equation showed a significant difference which confirms that the orifice equation cannot be always used for CIRCULAR leaks. In the study of leakage exponent, it was found that for polyethylene pipes, the leakage exponent is higher than value of 0.5 mentioned in the other studies and it can take different values depending on the leakage position in the network. Increasing the hole diameter did not affect the leakage exponent, but increased the leakage coefficient. On the other hand, for steel pipes, the leakage coefficient was fixed and the exponent remained around 0.5. Finally, the results showed the usefulness of the developed hydraulic analysis model for implementing the scenarios defined in this study.

In this paper we discuss the usual derivation of Hawking radiation for a spherical symmetric black hole and the problem connected with the appearance of high frequencies in the derivation of Hawking radiation. The important view of this paper is that problem may be overcomed if one takes the back reaction effect into account. We try to solve the problem by a heuristic method; this will confront us with the well known cosmological constant problem.

The film cooling effectiveness of a staggered arrangement of small and large HOLES was investigated. The small auxiliary HOLES were located normal to the cooled surface, whereas the large main HOLES had an inclination angle of 30°. The center points of the small HOLES were located upstream, downstream, and in the same position as the main HOLES. A hole pitch (P/D) of 3 and a thickness (t/D) of 3 were considered. The film cooling performance of the hole in trench structure and the cylindrical hole was also determined. The numerical results show that large-scale vortices caused by the auxiliary hole injection inhibit the development of vortices caused by the main hole in the streamwise direction. This result differs from that of anti-vortex film cooling. Compared to the baseline, the increase in the surface-averaged values is 15-22% for the staggered arrangement, depending on the blowing ratio (0. 5 to 2. 0). The positions of the auxiliary HOLES have an effect on the spanwise-averaged values.

In this work, we consider a static spherically symmetric charged regular black hole to investigate arbitrarily high centre of mass energy near the horizon with particle collision for extremal case in the equatorial plane ($theta=pi/2$). Here we also study CIRCULAR geodesics and find the ISCO and MBCO redii. We analysis the two neutral particles collision with same masses and different masses. Also we analyze the particle collision with massless photon and photon-photon collision near the horizon of this regular black hole to calculate centre of mass energy.

When tensions inside a country are not developed throughout the country, and are continued in specific regions, a sense of regionalism, as opposed to nationalism, develops among the people of the region.This sense something leads to the strengthening of decentralization, and as a result damages national unity. In developed countries, where the sense of regionalism is in its lowest possible level, what threatens the governments are governmental HOLES in which organized crime, without fanaticism towards local identity, challenges the existence of the governments. These HOLES can be social, cultural, or economic.Major HOLES in Iran’s government are: drug trafficking and distribution, growth of illegality, spreading of crime and threats to the health of the society, illegal immigrations, political decision making centers which are against the government, and those who challenge the governmental structure.To tackle these HOLES, governments employ similar and sometimes unique policies. Iran’s government is no exception. Regarding political HOLES, governments are very sensitive and specify huge budgets to abolish them. Governments are less sensitive to recognize and abolish social HOLES’ since the existence of these HOLES is not considered as a threat to the governments and mainly people suffer from them. Economic HOLES are sometimes created by the governments, and sometimes abolished by the governments to keep their bases.Finally, cultural HOLES which sometimes lead to the continuation of the governments are ignored by the governments and continue to exist.In this article, governments’ HOLES in general, and Iran’s government’s HOLES in particular are discussed.