10,188 research outputs found

    High voltage solid-state relay

    Get PDF
    Hybrid microelectronics relay has characteristics significantly superior to conventional solid state relays. Relay provides 2500 Vdc input to output isolation and operates from high threshold logic signal to switch load of 400 Vdc at 2 mA. Technology should be of interest to manufacturers of discrete components

    The water problem in Iowa

    Get PDF
    Water deficiencies throughout Iowa and other Midwest states the past 3 years have re-emphasized the importance of water to our farms and cities. Cities have had to resort to more costly means of procuring adequate water for their citizens. Farmers have been digging deeper wells, constructing ponds and hauling water to meet their domestic and livestock needs. Many farmers have started to use or have contemplated using water from streams and wells to irrigate their crops. Industries are becoming increasingly concerned with the availability of water as a major factor in locating and expanding plants. Experience during the last 3 years has demonstrated that water problems are aggravated periodically by rainfall deficiencies. However, these periodic aggravations emphasize but do not explain the basic water problem before us. In the main our water problems result from greatly increased demands upon available water supplies. These increasing demands stem from two factors: (1) a growing population and (2) an increasing per capita consumption. These two elements of the increasing demand for water show no indication of relaxing their rates of increase

    The multiple junction edge illuminated solar cell

    Get PDF
    The multiple junction edge illuminated solar cell was devised for high voltage low current applications. Devices to be flight tested in early 1974 with 96 series connected PNN+ junctions in a 2 cm X 2.3 cm size deliver 36 volts at 1 milliampere. Test data of M-J cells fabricated with resistivities of 10, 50, 100, 200, 450, and 1000 ohm cm silicon are presented and problem areas are discussed. An additional potential application of the M-J cell lies in ultilization of its high intensity performance that has been demonstrated at levels in excess of 100 AMO suns

    Second Epoch Global VLBI Observations of Compact Radio Sources in the M82 Starburst Galaxy

    Full text link
    We have presented the results of a second epoch of global Very Long Baseline Interferometry observations, taken on 23 February 2001 at a wavelength of 18 cm, of the central kiloparsec of the nearby starburst galaxy Messier 82. These observations were aimed at studying the structural and flux evolution of some of the compact radio sources in the central region that have been identified as supernova remnants. The objects 41.95+575 and 43.31+592 have been studied, expansion velocities of 2500 +/- 1200 km/s and 7350 +/- 2100 km/s respectively have been derived. Flux densities of 31.1 +/- 0.3 mJy and 17.4 +/- 0.3 mJy have been measured for the two objects. These results are consistent with measurements and predictions from previous epochs.Comment: 5 pages, 3 figures. To be published on the accompanying CD of the Proceedings of IAU Colloquium 192: Supernova

    Professional practices, training, and funding mechanisms: A survey of pediatric primary care psychologists

    Get PDF
    The integration of mental health services in primary care settings has expanded rapidly in recent years with psychologists being at the forefront of efforts to promote healthy behaviors, reduce disease, and care for behavioral, emotional, and developmental needs to promote overall health and well-being for children and families (Asarnow, Kolko, Miranda,&Kazak, 2017; Stancin& Perrin, 2014). While there are many psychologists working in pediatric primary care (PPC), little is known about the specific activities that these psychologists engage in, the training they receive, or funding mechanisms that support their work. This study sought to address this gap in the literature through a survey of psychologists working in PPC. An anonymous online survey was disseminated to members of professional organizations and listservs who were identified as having interest in PPC. Psychologists (N-65) currently practicing in PPC completed the survey by reporting on clinical roles and practices, professional training, practice settings, and funding supports in PPC settings. Results indicate that psychologists assume a number of roles in PPC including providing individual and family therapy, conducting screenings for child mental health concerns, and providing consultation to medical colleagues. Many psychologists also provide supervision and offer educational opportunities for those in related fields, such as medicine and social work. Engagement in research activities was identified as a secondary activity. It was reported that a number of clinical activities were not billed for on a regular basis. Additional areas of research will be discussed along with implications for clinical services in PPC.. © 2017 American Psychological Association

    A Preliminary Model of the Hydrologic-Sociologic Flow System of an Urban Area

    Get PDF
    This report describes the first phase of a larger study which is directed toward the development of a general technique for analyzing and solving urban metropolitan hydrologic problems through a joint consideration of both the physical and social dimensions. This report is limited to the preliminary work of identification of social variables, the first steps in assigning mathematical values to them, and developing a mathematical format for these variables. In addition, the physical-hydrologic system is identified for purposes of clarifying the elements in that system. The ultimate objective of the entire study is directed toward discovering a theoretical and generally applicable mathematical model of both the physical and social dimensions involved in metropolitan flooding problems

    15 years of VLBI observations of two compact radio sources in Messier 82

    Full text link
    We present the results of a second epoch of 18cm global Very Long-Baseline Interferometry (VLBI) observations, taken on 23 February 2001, of the central kiloparsec of the nearby starburst galaxy Messier 82. These observations further investigate the structural and flux evolution of the most compact radio sources in the central region of M82. The two most compact radio objects in M82 have been investigated (41.95+575 and 43.31+592). Using this recent epoch of data in comparison with our previous global VLBI observations and two earlier epochs of European VLBI Network observations we measure expansion velocities in the range of 1500-2000km/s for 41.95+575, and 9000-11000km/s for 43.31+592 using various independent methods. In each case the measured remnant expansion velocities are significantly larger than the canonical expansion velocity (500km/s) of supernova remnants within M82 predicted from theoretical models. In this paper we discuss the implications of these measured expansion velocities with respect to the high density environment that the SNR are expected to reside in within the centre of the M82 starburst.Comment: Accepted for publication in MNRAS, 9 pages, 8 figure

    Graph Annotations in Modeling Complex Network Topologies

    Full text link
    The coarsest approximation of the structure of a complex network, such as the Internet, is a simple undirected unweighted graph. This approximation, however, loses too much detail. In reality, objects represented by vertices and edges in such a graph possess some non-trivial internal structure that varies across and differentiates among distinct types of links or nodes. In this work, we abstract such additional information as network annotations. We introduce a network topology modeling framework that treats annotations as an extended correlation profile of a network. Assuming we have this profile measured for a given network, we present an algorithm to rescale it in order to construct networks of varying size that still reproduce the original measured annotation profile. Using this methodology, we accurately capture the network properties essential for realistic simulations of network applications and protocols, or any other simulations involving complex network topologies, including modeling and simulation of network evolution. We apply our approach to the Autonomous System (AS) topology of the Internet annotated with business relationships between ASs. This topology captures the large-scale structure of the Internet. In depth understanding of this structure and tools to model it are cornerstones of research on future Internet architectures and designs. We find that our techniques are able to accurately capture the structure of annotation correlations within this topology, thus reproducing a number of its important properties in synthetically-generated random graphs
    corecore