Communications systems technology assessment study. Volume 2: Results

The cost and technology characteristics are examined for providing special satellite services at UHF, 2.5 GHz, and 14/12 GHz. Considered are primarily health, educational, informational and emergency disaster type services. The total cost of each configuration including space segment, earth station, installation operation and maintenance was optimized to reduce the user's total annual cost and establish preferred equipment performance parameters. Technology expected to be available between now and 1985 is identified and comparisons made between selected alternatives. A key element of the study is a survey of earth station equipment updating past work in the field, providing new insight into technology, and evaluating production and test methods that can reduce costs in large production runs. Various satellite configurations were examined. The cost impact of rain attenuation at Ku-band was evaluated. The factors affecting the ultimate capacity achievable with the available orbital arc and available bandwidth were analyzed

Changes to zooplankton community structure following colonization of a small lake by Leptodora kindti

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109963/1/lno2004494part21239.pd

The AMSC mobile satellite system

The American Mobile Satellite Consortium (AMSC) Mobile Satellite Service (MSS) system is described. AMSC will use three multi-beam satellites to provide L-band MSS coverage to the United States, Canada and Mexico. The AMSC MSS system will have several noteworthy features, including a priority assignment processor that will ensure preemptive access to emergency services, a flexible SCPC channel scheme that will support a wide diversity of services, enlarged system capacity through frequency and orbit reuse, and high effective satellite transmitted power. Each AMSC satellite will make use of 14 MHz (bi-directional) of L-band spectrum. The Ku-band will be used for feeder links

Mobile satellite service in the United States

Mobile satellite service (MSS) has been under development in the United States for more than two decades. The service will soon be provided on a commercial basis by a consortium of eight U.S. companies called the American Mobile Satellite Consortium (AMSC). AMSC will build a three-satellite MSS system that will offer superior performance, reliability and cost effectiveness for organizations requiring mobile communications across the U.S. The development and operation of MSS in North America is being coordinated with Telesat Canada and Mexico. AMSC expects NASA to provide launch services in exchange for capacity on the first AMSC satellite for MSAT-X activities and for government demonstrations

Explaining the Rise in Antebellum Pauperism: New Evidence

The 1850s witnessed one of the earliest American history. During the decade the proportion of individuals receiving public assistance -- increased from 5.8 in 1850 to 10.2 in 1860, an increase of 76 percent. Previous attempts to explain the increase in antebellum pauperism have been hampered by the available published data, which are too aggregated to be of much use. This paper explores the determinants of antebellum pauperism using previously unexploited archival data drawn from the manuscript censuses of social statistics. These records provided detailed evidence on the incidence of pauperism at the county level. We find that about half of the increase in pauperism can be attributed to falling real wages during the decade. Contributing factors were increased immigration and urbanization.

Noise propagation issues in Belle II pixel detector power cable

The vertex detector used in the upgrade of High-Energy physics experiment Belle II includes DEPFET pixel detector (PXD) technology. In this complex topology the power supply units and the front-end electronics are connected through a PXD power cable bundle which may propagate the output noise from the power supplies to the vertex area. This paper presents a study of the propagation of noise caused by power converters in the PXD cable bundle based on Multi-conductor Transmission Line (MTL) theory. The work exposes the effect of the complex cable topology and shield connections on the noise propagation, which has an impact on the requirements of the power supplies. This analysis is part of the electromagnetic compatibility based design focused on functional safety to define the shield connections and power supply specifications required to ensure the successful integration of the detector and, specifically, to achieve the designed performance of the front-end electronics

Susceptibility characterization of beam pipe radiated noise for the PXD detector in Belle II experiment

The new Pixel Vertex Detector (PXD) used in the upgrade of the high energy physics experiment Belle II is based on the DEPFET technology. Since the PXD is 2 mm far from the beam pipe, the effects of radiated interferences may be taken into account. Though the EM wave associated to the beam is very well confined (skin depth), the beam pipe is grounded to the accelerator and it may have noise currents on its external face due to pumps, auxiliary electronics, power converters, etc. which may produce radiated noise (H field). This analysis is part of the EMC approach that covers the analysis of the emissions and immunity characteristics, as well as the coupling phenomena and grounding issues to define the susceptibility levels required to ensure the successful integration of the detector and, specifically, to achieve the designed performance of the front-end electronics

Peer-to-peer, community self-consumption, and transactive energy: A systematic literature review of local energy market models

Peer-to-peer, community or collective self-consumption, and transactive energy markets offer new models for trading energy locally. Over the past five years, there has been significant growth in the amount of academic literature examining how these local energy markets might function. This systematic literature review of 139 peer-reviewed journal articles examines the market designs used in these energy trading models. A modified version of the Business Ecosystem Architecture Modelling framework is used to extract market model information from the literature, and to identify differences and similarities between the models. This paper examines how peer-to-peer, community self-consumption and transactive energy markets are described in current literature. It explores the similarities and differences between these markets in terms of participation, governance structure, topology, and design. This paper systematises peer-to-peer, community self-consumption and transactive energy market designs, identifying six archetypes. Finally, it identifies five evidence gaps which require future research before these markets could be widely adopted. These evidence gaps are the lack of: consideration of physical constraints; a holistic approach to market design and operation; consideration about how these market designs will scale; consideration of information security; and, consideration of market participant privacy