Simulation of TunneLadder traveling-wave tube cold-test characteristics: Implementation of the three-dimensional, electromagnetic circuit analysis code micro-SOS

The three-dimensional, electromagnetic circuit analysis code, Micro-SOS, can be used to reduce expensive time-consuming experimental 'cold-testing' of traveling-wave tube (TWT) circuits. The frequency-phase dispersion characteristics and beam interaction impedance of a TunneLadder traveling-wave tube slow-wave structure were simulated using the code. When reasonable dimensional adjustments are made, computer results agree closely with experimental data. Modifications to the circuit geometry that would make the TunneLadder TWT easier to fabricate for higher frequency operation are explored

Nano-Engineering Defect Structures on Graphene

We present a new way of nano-engineering graphene using defect domains. These regions have ring structures that depart from the usual honeycomb lattice, though each carbon atom still has three nearest neighbors. A set of stable domain structures is identified using density functional theory (DFT), including blisters, ridges, ribbons, and metacrystals. All such structures are made solely out of carbon; the smallest encompasses just 16 atoms. Blisters, ridges and metacrystals rise up out of the sheet, while ribbons remain flat. In the vicinity of vacancies, the reaction barriers to formation are sufficiently low that such defects could be synthesized through the thermally activated restructuring of coalesced adatoms.Comment: 4 pages, 5 figure

The legacy of stockless organic conversion strategies

Huxham et al. (2005) reported the impacts of seven conversion strategies on the first organic crop (winter wheat). This paper investigates the effect of the conversion strategies on the second (winter beans) and third (winter oats) organic crops, thereby extending the analysis throughout the fi rst complete rotation. Conversion strategy had a significant impact on organic bean yield, which ranged from 2.84 to 3.62 t ha-1 and organic oat yield, which ranged from 3.24 to 4.17 t ha-1. In the organic bean crop, weed abundance prior to harvest, along with soil texture, accounted for 70% of yield variation. For the oats, soil mineral nitrogen in November together with weed abundance in April, accounted for 72% of the variation in yield. Annual average gross margins, calculated over the two year conversion period and the first three organic crops, ranged from £274 to £459 ha-1

Investigations of a bearing fault detector for railroad bearings

The laboratory tests are described which were conducted on new and damaged bearings to determine the feasibility of using high-frequency vibration as a diagnostic tool. A high-frequency band pass filter and demodulator was assembled to permit field measurements of the high-frequency vibrations. Field tests were conducted on an actual truck and on an axle assembly run in a grease test rig. These field tests were directed toward demonstration of the suitability and capabilities of the high-frequency technique for field application. Two specific areas of field application were identified as being cost effective for railroad use. One area is the examination of railroad roller bearings at a derailment site, and the second is as a wayside detector to supplement present hot box detectors for defective roller bearings

Dimensional crossover in a layered ferromagnet detected by spin correlation driven distortions

Magneto-elastic distortions are commonly detected across magnetic long-range ordering (LRO) transitions. In principle, they are also induced by the magnetic short-range ordering (SRO) that precedes a LRO transition, which contains information about short-range correlations and energetics that are essential for understanding how LRO is established. However these distortions are difficult to resolve because the associated atomic displacements are exceedingly small and do not break symmetry. Here we demonstrate high-multipole nonlinear optical polarimetry as a sensitive and mode selective probe of SRO induced distortions using CrSiTe$_3$ as a testbed. This compound is composed of weakly bonded sheets of nearly isotropic ferromagnetically interacting spins that, in the Heisenberg limit, would individually be impeded from LRO by the Mermin-Wagner theorem. Our results show that CrSiTe$_3$ evades this law via a two-step crossover from two- to three-dimensional magnetic SRO, manifested through two successive and previously undetected totally symmetric distortions above its Curie temperature.Comment: 17 pages main text, 4 figures, 12 pages supplementary informatio

Lost: The Crisis Of Jobless and Out Of School Teens and Young Adults In Chicago, Illinois and the U.S.

This report contains compilations and calculations of various employment data for males and females 16 to 24 years old by race/ethnicity from 2005 to 2014, comparing Chicago, Illinois, the U.S. and in some instances, adding Los Angeles and New York. Besides an array of figures and tables, the report contains GIS generated maps that illustrate the relationship between employment data and population distribution by race/ethnicity. A significant contribution of this report is its demonstration that low rates of employment are spatially concentrated in neighborhoods that are also racially segregated. This report clearly highlights that youth employment rates are tied to conditions in neighborhoods and cannot be seen as distinct from what is happening in the neighborhoods themselves. The devastation of unemployment in turn, wreaks havoc on the neighborhood

Art-based business

With its exclusive focus on profit-making, modern-day businesses tend to violate the integrity and diversity of natural ecosystems, the autonomy and culture of local communities and the chance that future generations will lead a decent life. The core of the metaphysics of modern-day business is what Martin Heidegger calls “calculative thinking”. It is contrasted with poetic thinking represented by genuine art. To preserve nature and to satisfy human needs, gentle, careful ways of undertaking economic activities are needed. The paper analyses the cases of Illy Café and Brunello Cucinelli as art-based companies to show that art can inspire business to become more aesthetic organization engaged in socio-ecological value creation and the enrichment of the quality of life