Abolishing the maximum tension principle

We find the series of example theories for which the relativistic limit of maximum tension $F_{max} = c^4/4G$ represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.Comment: 5 pages, no figures, REVTEX4-1, a typo in abstract correcte

Varying constants entropic--Λ\LambdaCDM cosmology

We formulate the basic framework of thermodynamical entropic force cosmology which allows variation of the gravitational constant $G$ and the speed of light $c$. Three different approaches to the formulation of the field equations are presented. Some cosmological solutions for each framework are given and one of them is tested against combined observational data (supernovae, BAO, and CMB). From the fit of the data it is found that the Hawking temperature numerical coefficient $\gamma$ is two to four orders of magnitude less than usually assumed on the geometrical ground theoretical value of $O(1)$ and that it is also compatible with zero. Besides, in the entropic scenario we observationally test that the fit of the data is allowed for the speed of light $c$ growing and the gravitational constant $G$ diminishing during the evolution of the universe. We also obtain a bound on the variation of $c$ to be $\Delta c/c \propto 10^{-5} >0$ which is at least one order of magnitude weaker than the quasar spectra observational bound.Comment: Matched with published version. some changes in Section VII, 15 page

Alterations in the complement cascade in post-traumatic stress disorder

<p>Abstract</p> <p>Background</p> <p>In the present study we assessed the functional state of the major mediator of the immune response, the complement system, in post-traumatic stress disorder (PTSD).</p> <p>Methods</p> <p>Thirty one PTSD patients within 13 years from traumatic event and the same number of sex- and age-matched healthy volunteers were involved in this study. In the blood serum of the study subjects hemolytic activities of the classical and alternative complement pathways, as well as the activities of the individual complement components have been measured. Correlation analysis between all measured parameters was also performed.</p> <p>Results</p> <p>According to the results obtained PTSD is characterized by hyperactivation of the complement classical pathway, hypoactivation of the complement alternative pathway and overactivation of the terminal pathway.</p> <p>Conclusions</p> <p>The results obtained provide further evidence on the involvement of the inflammatory component in pathogenesis of PTSD.</p

Quantum tunneling from scalar fields in rotating black strings

Using the Hamilton-Jacobi method of quantum tunneling and complex path integration, we study Hawking radiation of scalar particles from rotating black strings. We discuss tunneling of both charged and uncharged scalar particles from the event horizons. For this purpose, we use the Klein-Gordon equation and find the tunneling probability of outging scalar particles. The procedure gives Hawking temperature for rotating charged black strings as well.Comment: Corrections and change

Issues in Statistical Modelling of Human Capital and Economic Growth Nexus

The human capital and growth relationship has been subject to considerable debate in economic literature. The empirical growth models are beset with problems ranging from theoretical frameworks and statistical modelling to estimation procedures. Due to non-availability of precise human capital variable, theoretical knowledge fails when pitched against empirical data. This paper endeavors to answer four main questions that have been figured out prominently in this debate: Is there a direct interplay between human capital and growth? Are parametric techniques incapable of capturing non-linear aspects of human capital-growth relationship as compared to semi-parametric techniques? Are estimates of human capital sensitive to proxy of human capital variables? Are estimates of human capital sensitive to estimation techniques? Our findings reveal that human capital has a well-established role in accelerating growth through both its ‘level effects’ and ‘rate effects’. The results are not sensitive to definition of education variable but are rather technique dependent. The semi-parametric model provides sufficient evidence for non-linearity in human capital-growth relationship contrary to parametric models

Activation characteristics of different steel alloys proposed for near-term fusion reactors

Analyses have been made for different structural alloys proposed for the International Thermonuclear Experimental Reactor (ITER). Candidate alloys include austenitic steels stabilized with nickel (NiSS) or manganese (MnSS). The radioactivity, the decay heat, and the waste disposal rating of each alloy have been calculated for the inboard shield of the ITER design option utilizing water cooled solid breeder blanket. The results show, for the 55 cm inboard shield and after 3 MW.yr/m2 fluence, that the long term activation problems, e.g., radioactive waste, of the MnSS are much less than that of the NiSS. All the MnSS alloys considered are qualified as Class C or better low level waste. Most of the NiSS alloys are not qualified for near surface burial. However, the short term decay heat generation rate for the MnSS is much higher than that of the NiSS. 6 refs., 8 figs., 2 tabs

High temperature fusion reactor design

Fusion energy may have unique advantages over other systems as a source for high temperature process heat. A conceptual design of a blanket for a 7 m tokamak reactor has been developed that is capable of producing 1100/sup 0/C process heat at a pressure of approximately 10 atmospheres. The design is based on the use of a falling bed of MgO spheres as the high temperature heat transfer system. By preheating the spheres with energy taken from the low temperature tritium breeding part of the blanket, 1086 MW of energy can be generated at 1100/sup 0/C from a system that produces 3000 MW of total energy while sustaining a tritium breeding ratio of 1.07. The tritium breeding is accomplished using Li/sub 2/O modules both in front of (6 cm thick) and behind (50 cm thick) the high temperature ducts. Steam is used as the first wall and front tritium breeding module coolant while helium is used in the rear tritium breeding region. The system produces 600 MW of net electricity for use on the grid

Target design optimization for an electron accelerator driven subcritical facility with circular and square beam profiles.

A subcritical facility driven by an electron accelerator is planned at the Kharkov Institute of Physics and Technology (KIPT) in Ukraine for medical isotope production, materials research, training, and education. The conceptual design of the facility is being pursued through collaborations between ANL and KIPT. As part of the design effort, the high-fidelity analyses of various target options are performed with formulations to reflect the realistic configuration and the three dimensional geometry of each design. This report summarizes the results of target design optimization studies for electron beams with two different beam profiles. The target design optimization is performed via the sequential neutronic, thermal-hydraulic, and structural analyses for a comprehensive assessment of each configuration. First, a target CAD model is developed with proper emphasis on manufacturability to provide a basis for separate but consistent models for subsequent neutronic, thermal-hydraulic, and structural analyses. The optimizations are pursued for maximizing the neutron yield, streamlining the flow field to avoid hotspots, and minimizing the thermal stresses to increase the durability. In addition to general geometric modifications, the inlet/outlet channel configurations, target plate partitioning schemes, flow manipulations and rates, electron beam diameter/width options, and cladding material choices are included in the design optimizations. The electron beam interactions with the target assembly and the neutronic response of the subcritical facility are evaluated using the MCNPX code. the results for the electron beam energy deposition, neutron generation, and utilization in the subcritical pile are then used to characterize the axisymmetric heat generation profiles in the target assembly with explicit simulations of the beam tube, the coolant, the clad, and the target materials. Both tungsten and uranium are considered as target materials. Neutron spectra from tungsten and uranium are very similar allowing the use of either material in the subcritical assembly without changing its characteristics. However, the uranium target has a higher neutron yield, which increases the neutron flux of the subcritical assembly. Based on the considered dimensions and heat generation profiles, the commercial CFD software Star-CD is used for the thermal-hydraulic analysis of each target design to satisfy a set of thermal criteria, the most limiting of which being to maintain the water temperature 50 below the boiling point. It is found that the turbulence in the inlet channels dissipates quickly in narrow gaps between the target plates and, as a result, the heat transfer is limited by the laminar flow conditions. On average, 3-D CFD analyses of target assemblies agree well with 1-D calculations using RELAP (performed by KIPT). However, the recirculation and stagnation zones predicted with the CFD models prove the importance of a 3-D analysis to avoid the resulting hotspots. The calculated temperatures are subsequently used for the structural analysis of each target configuration to satisfy the other engineering design requirements. The thermo-structural calculations are performed mostly with NASTRAN and the results occasionally compared with the results from MARC. Both, NASTRAN and MARC are commercially available structural-mechanics analysis software. Although, a significant thermal gradient forms in target elements along the beam direction, the high thermal stresses are generally observed peripherally around the edge of thin target disks/plates. Due to its high thermal conductivity, temperatures and thermal stresses in tungsten target are estimated to be significantly lower than in uranium target. The deformations of the target disks/plates are found to be insignificant, which eliminate concerns for flow blockages in narrow coolant channels. Consistent with the specifications of the KIPT accelerator to be used in this facility, the electron beam power is 100-kW with electron energy in the range of 100 to 200 MeV. As expected, the 100 MeV electrons deposit their energy faster while the 200-MeV electrons spread their energy deposition further along the beam direction. However in that electron energy range, the energy deposition profiles near the beam window require very thin target plates/disks to limit the temperatures and thermal stresses

Prediction of airborne radiated noise from lightly loaded lubricated meshing gear teeth

This paper introduces a novel analytical method for determination of gear airborne noise under lightly loaded conditions, often promoting gear rattle of loose unengaged gear pairs. The system examined comprises a single gear pair, modelled through integrated contact tribology and inertial transient dynamics. Lubricant film thickness, structural vibration and airborne gear noise are predicted and correlated with experimental measurements undertaken in a semi-anechoic environment. Good agreement is noticed between the numerical predictions and the experimental measurements. The presented model is capable of estimating the airborne radiated gear noise levels and the dynamic behaviour of gear pairs under different operating conditions, with superimposed impulsive input speed harmonics