Cosmology With A Dark Refraction Index

We review Gordon's optical metric and the transport equations for the amplitude and polarization of a geometrical optics wave traveling in a gravity field. We apply the theory to the FLRW cosmologies by associating a refraction index with the cosmic fluid. We then derive an expression for the accumulated effect of a refraction index on the distance redshift relations and fit the Hubble curve of current supernova observations with a non-accelerating cosmological model. We also show that some observational effects caused by inhomogeneities, e.g. the Sachs-Wolfe effect, can be interpreted as being caused by an effective index of refraction, and hence this theory could extend to other speed of light communications such as gravitational radiation and neutrino fluxes.Comment: 21 pages, 3 figure

Solid domains in lipid vesicles and scars

The free energy of a crystalline domain coexisting with a liquid phase on a spherical vesicle may be approximated by an elastic or stretching energy and a line tension term. The stretching energy generally grows as the area of the domain, while the line tension term grows with its perimeter. We show that if the crystalline domain contains defect arrays consisting of finite length grain boundaries of dislocations (scars) the stretching energy grows linearly with a characteristic length of the crystalline domain. We show that this result is critical to understand the existence of solid domains in lipid-bilayers in the strongly segregated two phase region even for small relative area coverages. The domains evolve from caps to stripes that become thinner as the line tension is decreased. We also discuss the implications of the results for other experimental systems and for the general problem that consists in finding the ground state of a very large number of particles constrained to move on a fixed geometry and interacting with an isotropic potential.Comment: 7 pages, 6 eps figure

Linear response strength functions with iterative Arnoldi diagonalization

We report on an implementation of a new method to calculate RPA strength functions with iterative non-hermitian Arnoldi diagonalization method, which does not explicitly calculate and store the RPA matrix. We discuss the treatment of spurious modes, numerical stability, and how the method scales as the used model space is enlarged. We perform the particle-hole RPA benchmark calculations for double magic nucleus 132Sn and compare the resulting electromagnetic strength functions against those obtained within the standard RPA.Comment: 9 RevTeX pages, 11 figures, submitted to Physical Review

A one-sided Prime Ideal Principle for noncommutative rings

Completely prime right ideals are introduced as a one-sided generalization of the concept of a prime ideal in a commutative ring. Some of their basic properties are investigated, pointing out both similarities and differences between these right ideals and their commutative counterparts. We prove the Completely Prime Ideal Principle, a theorem stating that right ideals that are maximal in a specific sense must be completely prime. We offer a number of applications of the Completely Prime Ideal Principle arising from many diverse concepts in rings and modules. These applications show how completely prime right ideals control the one-sided structure of a ring, and they recover earlier theorems stating that certain noncommutative rings are domains (namely, proper right PCI rings and rings with the right restricted minimum condition that are not right artinian). In order to provide a deeper understanding of the set of completely prime right ideals in a general ring, we study the special subset of comonoform right ideals.Comment: 38 page

Two-gap superconductivity in single crystal Lu2_2Fe3_3Si5_5 from penetration depth measurements

Single crystal of Lu$_2$Fe$_3$Si$_5$ was studied with the tunnel-diode resonator technique in Meissner and mixed states. Temperature dependence of the superfluid density provides strong evidence for the two-gap superconductivity with almost equal contributions from each gap of magnitudes $\Delta_1/k_BT_c=1.86$ and $\Delta_1/k_BT_c=0.54$. In the vortex state, pinning strength shows unusually strong temperature dependence and is non-monotonic with the magnetic field (peak effect). The irreversibility line is sharply defined and is quite distant from the $H_{c2}(T)$, which hints on to enhanced vortex fluctuations in this two-gap system. Altogether our findings provide strong electromagnetic - measurements support to the two-gap superconductivity in Lu$_2$Fe$_3$Si$_5$ previously suggested from specific heat measurements

Methodology for cokemaking technology selection for operating conditions and expansion of iron and steel works

Selection of cokemaking technology within an Iron & Steel Works (I&SW) setting is a complicated problem, involving analysis of coal quality, coke demand and supply, environmental regulations, and the plant energy balance. The methodology involves coal blend selection, preparation, charging, cokemaking and quenching technology selection to meet the blast furnaces’ coke quality requirements and the I&SW energy balance. Hatch’s mass and energy balance, OPEX, CAPEX, Energy/CO2 and Financial Models provide the client with NPV/IRR ranking and sensitivity analysis to assist in selecting the best strategy amongst by-product or heat recovery ovens, charging and quenching systems for replacement or expansion programs

Case Report: A Neocystostomy Perforation Presenting as a Gallstone

AbstractAn 83-year-old man, with a surgical history of radical cystectomy with simultaneous construction of a neobladder 13 years ago, presented clinically and radiologically as acute cholecystitis. Upon emergent exploratory laparotomy for his acute deterioration, a perforated neobladder was identified with its spilled stones in the gallbladder fossa, mimicking acute cholecystitis. This is the first case report of this presentation. Neobladder perforations should be considered in any patient who has undergone orthotopic bladder substitution, no matter how long it has been since the original reconstruction

Carbon Footprint of the Large Scale Gold Mining Industry of Ghana

Mining has been an important economic activity accounting for a substantial part of foreign exchange and government revenue. The gold mining sector has undergone considerable expansion due to liberalization with more foreign mining companies investing in the sector in particular large-scale open pit gold mining. Resultant expansion in mining has led to heightened environmental concerns and significant challenges due to key activities used in the mining operations hence contributing to greenhouse gas emissions. Investigations were conducted to assess the sources and key activities in large scale gold open pit mining operations in Ghana giving rise to greenhouse gas generation. The study adopted the Intergovernmental Panel on Climate Change (IPCC) guideline for estimating greenhouse gas inventory. The operational boundary as against the organizational boundary was considered for the study. The operational boundary was drawn around the physical mining site. Within this boundary, the emissions were quantified and reported under direct emission due to company activities (Scope 1) and indirect emissions from secondary use or activity (Scope 2). The study found that activities due to land use, blasting, fuel use to power mobile equipment and stationary combustion sources, electricity use and waste management were the contributing greenhouse gas emission sources in a large scale gold mining operation with electricity use and fuel used in transportation accounting for 92.46% of the total emissions. Average contribution of the large scale gold mining industry in Ghana to the total national greenhouse gas emission inventory for the country was established to be 11.08%

Methodology for Cokemaking Technology Selection

The objective of this article is the selection of cokemaking technology within an Iron & Steel Works (I&SW), involving analysis of coal quality, coke demand and supply, environmental regulations, and the plant energy balance. The methodology involves coal blend selection, preparation, charging, cokemaking and quenching technology selection to meet the blast furnaces’ coke quality requirements and the I&SW energy balance. Hatch’s mass and energy balance, OPEX, CAPEX, Energy/CO2 and Financial Models provide the client with NPV/IRR ranking and sensitivity analysis to assist in selecting the best strategy amongst by-product or heat recovery ovens, charging and quenching systems for replacement or expansion programs. The developedmethodology was successfully applied for development of coal and cokemaking strategy, estimation of required cokemaking capacity for the metallurgical giant, which incorporates four integrated iron and steel works, two stand alone coke plant and several coal and iron ore mines. Some of Hatch’s recommendationsare already implemented and tested by the client. The optimum selection of cokemaking technologies requires a careful analysis of the I&SW and companyspecific requirements in order to develop a techno-economic analysis that will provide the optimum strategy to get the most from existing assets and to ensure competitive future coke production. Development by Hatch methodology could be successfully applied for selection and construction of green site cokemaking facilities as well as for brown field modernizations. Keywords: By-product cokemaking, heat recovery cokemaking, energy balance, financial analysi