1,654 research outputs found
First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control System
First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control
System The roots of ATLAS (Argonne Tandem-Linac Accelerator System) date back
to the early 1960s. Located at the Argonne National Laboratory, the accelerator
has been designated a National User Facility, which focuses primarily on
heavy-ion nuclear physics. Like the accelerator it services, the control system
has been in a constant state of evolution. The present real-time portion of the
control system is based on the commercial product Vsystem [1]. While Vsystem
has always been capable of distributed I/O processing, the latest offering of
this product provides for the use of relatively inexpensive PC hardware and
software. This paper reviews the status of the ATLAS control system, and
describes first experiences with PC distributed I/O.Comment: ICALEPCS 2001 Conference, PSN WEAP027, 3 pages, 1 figur
Composite Reflective/Absorptive IR-Blocking Filters Embedded in Metamaterial Antireflection Coated Silicon
Infrared (IR) blocking filters are crucial for controlling the radiative
loading on cryogenic systems and for optimizing the sensitivity of bolometric
detectors in the far-IR. We present a new IR filter approach based on a
combination of patterned frequency selective structures on silicon and a thin
(50 thick) absorptive composite based on powdered reststrahlen
absorbing materials. For a 300 K blackbody, this combination reflects
50\% of the incoming light and blocks \textgreater 99.8\% of the total
power with negligible thermal gradients and excellent low frequency
transmission. This allows for a reduction in the IR thermal loading to
negligible levels in a single cold filter. These composite filters are
fabricated on silicon substrates which provide excellent thermal transport
laterally through the filter and ensure that the entire area of the absorptive
filter stays near the bath temperature. A metamaterial antireflection coating
cut into these substrates reduces in-band reflections to below 1\%, and the
in-band absorption of the powder mix is below 1\% for signal bands below 750
GHz. This type of filter can be directly incorporated into silicon refractive
optical elements
Advanced ceramic coating development for industrial/utility gas turbine applications
The effects of ceramic coatings on the lifetimes of metal turbine components and on the performance of a utility turbine, as well as of the turbine operational cycle on the ceramic coatings were determined. When operating the turbine under conditions of constant cooling flow, the first row blades run 55K cooler, and as a result, have 10 times the creep rupture life, 10 times the low cycle fatigue life and twice the corrosion life with only slight decreases in both specific power and efficiency. When operating the turbine at constant metal temperature and reduced cooling flow, both specific power and efficiency increases, with no change in component lifetime. The most severe thermal transient of the turbine causes the coating bond stresses to approach 60% of the bond strengths. Ceramic coating failures was studied. Analytic models based on fracture mechanics theories, combined with measured properties quantitatively assessed both single and multiple thermal cycle failures which allowed the prediction of coating lifetime. Qualitative models for corrosion failures are also presented
The Relational Database Aspects of Argonne's ATLAS Control System
The Relational Database Aspects of Argonnes ATLAS Control System Argonnes
ATLAS (Argonne Tandem Linac Accelerator System) control system comprises two
separate database concepts. The first is the distributed real-time database
structure provided by the commercial product Vsystem [1]. The second is a more
static relational database archiving system designed by ATLAS personnel using
Oracle Rdb [2] and Paradox [3] software. The configuration of the ATLAS
facility has presented a unique opportunity to construct a control system
relational database that is capable of storing and retrieving complete archived
tune-up configurations for the entire accelerator. This capability has been a
major factor in allowing the facility to adhere to a rigorous operating
schedule. Most recently, a Web-based operator interface to the control systems
Oracle Rdb database has been installed. This paper explains the history of the
ATLAS database systems, how they interact with each other, the design of the
new Web-based operator interface, and future plans.Comment: ICALEPCS 2001 Conference, PSN WEAP066, 3 pages, 3 figure
Designing for digital wellbeing: A research & practice agenda
Traditionally, many consumer-focused technologies have been designed to maximize user engagement with their products and services. More recently, many technology companies have begun to introduce digital wellbeing features, such as for managing time spent and for encouraging breaks in use. These are in the context of, and likely in response to, renewed concerns in the media about technology dependency and even addiction. The promotion of technology abstinence is also increasingly widespread, e.g., via digital detoxes. Given that digital technologies are an important and valuable feature of many people's lives, digital wellbeing features are arguably preferable to abstinence
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WIPP panel simulations with gas generation
An important issue in nuclear waste repository performance is the potential for fracture development resulting in pathways for release of radionuclides beyond the confines of the repository. A series of demonstration calculations using structural finite element analyses are presented here to examine the effect of internal gas generation on the response of a sealed repository. From the calculated stress fields, the most probable location for a fracture to develop was determined to be within the pillars interior to the repository for the range of parameter values considered. If a fracture interconnects the rooms and panels of the repository, fracture opening produces significant additional void volume to limit the excess gas pressure to less than 1.0 MPa above the overburden pressure. Consequently, the potential for additional fracture development into the barrier pillar is greatly reduced, which provides further confidence that the waste will be contained within the repository
Laboratory Focus on Improving the Culture of Biosafety: Statewide Risk Assessment of Clinical Laboratories That Process Specimens for Microbiologic Analysis
The Wisconsin State Laboratory of Hygiene challenged Wisconsin laboratories to examine their biosafety practices and improve their culture of biosafety. One hundred three clinical and public health laboratories completed a questionnaire-based, microbiology-focused biosafety risk assessment. Greater than 96% of the respondents performed activities related to specimen processing, direct microscopic examination, and rapid nonmolecular testing, while approximately 60% performed culture interpretation. Although they are important to the assessment of risk, data specific to patient occupation, symptoms, and travel history were often unavailable to the laboratory and, therefore, less contributory to a microbiology-focused biosafety risk assessment than information on the specimen source and test requisition. Over 88% of the respondents complied with more than three-quarters of the mitigation control measures listed in the survey. Facility assessment revealed that subsets of laboratories that claim biosafety level 1, 2, or 3 status did not possess all of the biosafety elements considered minimally standard for their respective classifications. Many laboratories reported being able to quickly correct the minor deficiencies identified. Task assessment identified deficiencies that trended higher within the general (not microbiology-specific) laboratory for core activities, such as packaging and shipping, direct microscopic examination, and culture modalities solely involving screens for organism growth. For traditional microbiology departments, opportunities for improvement in the cultivation and management of highly infectious agents, such as acid-fast bacilli and systemic fungi, were revealed. These results derived from a survey of a large cohort of small- and large-scale laboratories suggest the necessity for continued microbiology-based understanding of biosafety practices, vigilance toward biosafety, and enforcement of biosafety practices throughout the laboratory setting
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