10,188 research outputs found
High voltage solid-state relay
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
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
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
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
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
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
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
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
- …