A modified crack closure integral method for calculating stress intensity factors for cracked plates subject to bending loads

A method is developed to calculate strain energy release rates, G, or stress intensity factors, K, using only nodal forces and displacements from a standard finite element analysis code. The method is an extension of the modified crack closure integral (MCCI) approach to the bending of plates with through cracks. An examination of bending of plates with through cracks based on shear deformation theories has shown that the bending K depends strongly on the ratio of plate thickness, h, and half crack length, a. Hence, the need to examine the effect of h/a on the accuracy of G and K obtained by the MCCI approach is examined. The accuracy of the MCCI method is verified by analyzing a square plate with a central crack subjected to a uniform edge moment and comparing the results with those reported in the literature

Penn State axial flow turbine facility: Performance and nozzle flow field

The objective is to gain a thorough understanding of the flow field in a turbine stage including three-dimensional inviscid and viscid effects, unsteady flow field, rotor-stator interaction effects, unsteady blade pressures, shear stress, and velocity field in rotor passages. The performance of the turbine facility at the design condition is measured and compared with the design distribution. The data on the nozzle vane static pressure and wake characteristics are presented and interpreted. The wakes are found to be highly three-dimensional, with substantial radial inward velocity at most spanwise locations

Cooperation and Storage Tradeoffs in Power-Grids with Renewable Energy Resources

One of the most important challenges in smart grid systems is the integration of renewable energy resources into its design. In this work, two different techniques to mitigate the time varying and intermittent nature of renewable energy generation are considered. The first one is the use of storage, which smooths out the fluctuations in the renewable energy generation across time. The second technique is the concept of distributed generation combined with cooperation by exchanging energy among the distributed sources. This technique averages out the variation in energy production across space. This paper analyzes the trade-off between these two techniques. The problem is formulated as a stochastic optimization problem with the objective of minimizing the time average cost of energy exchange within the grid. First, an analytical model of the optimal cost is provided by investigating the steady state of the system for some specific scenarios. Then, an algorithm to solve the cost minimization problem using the technique of Lyapunov optimization is developed and results for the performance of the algorithm are provided. These results show that in the presence of limited storage devices, the grid can benefit greatly from cooperation, whereas in the presence of large storage capacity, cooperation does not yield much benefit. Further, it is observed that most of the gains from cooperation can be obtained by exchanging energy only among a few energy harvesting sources

End wall flows in rotors and stators of a single stage compressor

A computer code for solving the parabolized Navier-Stokes equations for internal flows was developed. Oscillations that develop in the calculation procedure are discussed. The measurements made in the hub and annulus wall boundary layers are summarized. The flow in the hub wall boundary layer, starting ahead of the inlet guide vanes to the inlet of the rotor is traced

Cosmologically Strengthening Hydrogen Atom in Black Hole Universe

With reference to the earlier proposed black hole model of cosmology, the authors proposed a unified model mechanism for understanding the light emission mechanism in cosmologically ‘strengthening hydrogen atom’. In this proposed model, characteristic cosmic mass, characteristic nuclear charge radius, Avogadro number and possible quantum states of electron seem to play a major role. Throughout the cosmic evolution, Planck’s constant seems to be a constant whereas the currently believed ‘reduced Planck’s constant’ seems to be a cosmological decreasing variable.With this new proposal - Hubble’s redshift interpretation, Super novae dimming and currently believed cosmic acceleration can be reviewed at fundamental level and a correct model of cosmology can be confirmed

Calculating the energy of electron in H-atom using modified SUSY physics

In this paper considering the authors previously proposed SUSy concept - ‘fermion and boson mass ratio is close to 2.26’ and considering the electroweak neutral boson, an attempt is made to understand the total energy of revolving electron in the hydrogen atom. thus in this paper authors succeeded in extending the basic applications of SUSY and electroweak theory to atomic level. With further research and analysis, the hidden secrets of electroweak unification can be understood very easily

On the Combined Role of Strong and Electroweak Interactions in Understanding Nuclear Binding Energy Scheme

An attempt is made toa model the atomic nucleus as a combination of bound and free or unbound nucleons. Due to strong interaction, bound nucleons help in increasing nuclear binding energy and due to electroweak interaction, free or unbound nucleons help in decreasing nuclear binding energy. In this context, with reference to proposed 4G model of final unification and strong interaction, recently we have developed a unified nuclear binding energy scheme with four simple terms, one energy coefficient of 10.1 MeV and two small numbers 0.0016 and 0.0019. In this paper, by eliminating the number 0.0019, we try to fine tune the estimation procedure of number of free or unbound nucleons pertaining to the second term with an energy coefficient of 11.9 MeV. Interesting observation is that, Z can be considered as a characteristic representation of range of number of bound isotopes of  Z.&nbsp

Applications of EM and Gravitational Force Strengths in Unification

By implementing the unified mass unit Mc≅√e2/4πεoG the authors made an attempt to fit and understand the key ‘quantum’ and ‘nuclear’ physical parameters. With MC and by considering the electromagnetic and gravitational force ratio of proton and electron - the nuclear charge radius, the Planck’s constant and the strong coupling constant can be fitted in a unified approach. Finally by considering the proton rest energy and the nuclear charge radius the authors made an attempt to fit the semi empirical mass formula energy coefficients and stable heavy elements in a very simple way

Role of Four Gravitational Constants in Nuclear Structure

This paper attempts to understand the role of the four gravitational constants in the nuclear structure whichhelps in understanding the nuclear elementary charge, the strong coupling constant, nuclear charge radii,nucleon magnetic moments, nuclear stability, nuclear binding energy and Neutron life time. The three assumed atomic gravitational constants help in understanding neutron-proton stability. Electromagnetic and nuclear gravitational constants play a role in understanding proton-electron mass ratio, Bohr radius and characteristic atomic radius. With reference to the weak gravitational constant, it is possible to predict the existence of a weakly interacting fermion of rest energy 585 GeV, called Higg’s fermion. Cosmological ‘dark matter’ research and observations can be carried out in this direction also

On the role of nuclear quantum gravity in understanding nuclear stability range of Z = 2 to 118

To understand the mystery of final unification, in our earlier publications, we proposed two bold concepts: 1) There exist three atomic gravitational constants associated with electroweak, strong and electromagnetic interactions. 2) There exists a strong elementary charge in such a way that its squared ratio with normal elementary charge is close to reciprocal of the strong coupling constant. In this paper we propose that, ℏc can be considered as a compound physical constant associated with proton mass, electron mass and the three atomic gravitational constants. With these ideas, an attempt is made to understand nuclear stability and binding energy. In this new approach, with reference to our earlier introduced coefficients k = 0.00642 and f = 0.00189, nuclear binding energy can be fitted with four simple terms having one unique energy coefficient. The two coefficients can be addressed with powers of the strong coupling constant. Classifying nucleons as ‘free nucleons’ and ‘active nucleons’, nuclear binding energy and stability can be understood. Starting from , number of isotopes seems to increase from 2 to 16 at and then decreases to 1 at For Z >= 84, lower stability seems to be, Alower=(2.5 to 2.531)Z