Finite element modeling of electromagnetic fields and waves using NASTRAN

The various formulations of Maxwell's equations are reviewed with emphasis on those formulations which most readily form analogies with Navier's equations. Analogies involving scalar and vector potentials and electric and magnetic field components are presented. Formulations allowing for media with dielectric and conducting properties are emphasized. It is demonstrated that many problems in electromagnetism can be solved using the NASTRAN finite element code. Several fundamental problems involving time harmonic solutions of Maxwell's equations with known analytic solutions are solved using NASTRAN to demonstrate convergence and mesh requirements. Mesh requirements are studied as a function of frequency, conductivity, and dielectric properties. Applications in both low frequency and high frequency are highlighted. The low frequency problems demonstrate the ability to solve problems involving media inhomogeneity and unbounded domains. The high frequency applications demonstrate the ability to handle problems with large boundary to wavelength ratios

Ecologic Relationships Between Bacteria and Algae in Mass Culture

Ecological relationships between bacteria and algae in mass cultur

Options for reshaping the railway

In many countries the mismatch between what the railways offer and what the customers want has caused significant economic inefficiency and severe financial strains for the railways and their government owners. The concept of the railway as a monolithic entity is so strong in many countries as to be a roadblock against reshaping the railway. The authors explore four options which can be used to reshape the railways. First is the lines of business option which improves accountability and responsiveness to markets. The second is the competitive access option which introduces intramodal competition in selected markets, while maintaining unitary control over most railway operations. The third is the"wholesaler"option which would accomplish an excellent marketing job, but the actual operation would remain in monolithic hands. Finally there is the"toll rail enterprise"option which comes closest to reflecting a theoretical model of marketing effectiveness, however it would generate potential operating conflicts and higher transaction costs. The authors show that one generalization holds true in all circumstances: a monolithic railway does not function well in a market economy in competition with privately owned, properly regulated competitors - especially trucking. The authors point out that solutions will vary, but the universal objective as an economy becomes more market driven is to make the railway more market sensitive.Railways Transport,Roads&Highways,Environmental Economics&Policies,Banks&Banking Reform,ICT Policy and Strategies

Transfer molding of PMR-15 polyimide resin

Transfer molding is an economically viable method of producing small shapes of PMR-15 polyimide. It is shown that with regard to flexural, compressive, and tribological properties transfer-molded PMR-15 polyimide is essentially equivalent to PMR-15 polyimide produced by the more common method of compression molding. Minor variations in anisotropy are predictable effects of molding design and secondary finishing operations

Comet Shoemaker‐Levy 9: No effect on the Io plasma torus

Observations of the Io plasma torus made before, during, and after the impact of Comet Shoemaker‐Levy 9 with Jupiter reveal no comet‐induced changes. Three weeks of high spectral‐resolution ground‐based visible spectroscopy show no changes larger than typical day‐to‐day variations in the torus densities, ion temperatures, or rotation velocities. Comparison with six months of identically obtained data from 1991 and 1992 also shows no differences

The Next Recruits: 16–18-year-olds and the United States\u27 War on Terror

For many who experienced it directly or indirectly, 9/11 marked a dramatic shift as the United States processed the attacks and went from a country at peace to a country at war. Though the attacks themselves were geographically targeted, 9/11 was a nationally traumatic event and resulted in the formation of a collective memory and national narrative across the country. With the War on Terror, the military became synonymous with patriotism, as leaders and the media invoked the trauma of Pearl Harbor and the glories of World War II. Military records from the time describe patriotism as the motivation behind the majority of enlistments following 9/11, contrasting the traditional motivation of money and economic opportunity. As the War on Terror nears the end of its second decade, with a recently announced Afghanistan troop surge, there is no end in sight, though the adversary spotlight has shifted from the Taliban and Al Qaeda to the Islamic State (IS). Drawing from the theories of collective memory, transgenerational trauma transmission, and militarism, this research explores how 16–18-year-olds talk about 9/11 and the War on Terror and how they understand their patriotic obligations to the War on Terror. Understanding this will be critical to understanding how the War on Terror proceeds for the next generation, including peacebuilding efforts and how the United States recruits for and staffs the military. Three sets of data, two semi-structured interviews and one questionnaire survey, demonstrate that in 2018, 9/11 is still a significant presence in teenagers’ lives. Though no signs of trauma were noted in participants, the significance of the attacks and their implications were evident in responses, reflecting the curation of a collective memory. Additionally, the military and the flag were central to participants’ understanding of patriotism and patriotic obligations in addition to practices such as voting