41 research outputs found
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Optimization of thermal design for nitrogen shield of JET cryopump
The reference design of JET cryopump nitrogen shield consists of an outer section made of copper chevrons fastened to two cooling tubes and an inner stainless steel section and backing plate with two cooling tubes. These tubes are fed in a parallel flow arrangement. The inlet flow is divided into two parallel paths so that both tubes on either section are always at the same temperature. This arrangement was selected due to concern about conduction between warm and cold parts of the shield during cooldown transients. If the heat loads are unequal, such a parallel flow arrangement can result in flow starvation in the path with higher heat load. This will cause large temperature differences and, ultimately, structural failure. Hence, an analysis was undertaken to investigate the conduction effects in the shield for other flow arrangements. 4 refs., 8 figs
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Pilot program to assess proposed basic quality assurance requirements in the medical use of byproduct materials
In January 1990, the Nuclear Regulatory Commission (NRC) proposed amendments to 10 CFR Part 35 that would require medical licensees using byproduct material to establish and implement a basic quality assurance program. A 60-day real-world trial of the proposed rules was initiated to obtain information beyond that generally found through standard public comment procedures. Volunteers from randomly selected institutions had opportunities to review the details of the proposed regulations and to implement these rules on a daily basis during the trial. The participating institutions were then asked to evaluate the proposed regulations based on their personal experiences. The pilot project sought to determine whether medical institutions could develop written quality assurance programs that would meet the eight performance-based objectives of proposed Section 35.35. In addition, the NRC wanted to learn from these volunteers if they had any recommendations on how the rule could be revised to minimized its cost and to clarify its objectives without decreasing its effectiveness. It was found that licensees could develop acceptable QA programs under a performance-based approach, that most licensee programs did meet the proposed objectives, and that most written QA plans would require consultations with NRC or Agreement State personnel before they would fully meet all objectives of proposed Section 35.35. This report describes the overall pilot program. The methodology used to select and assemble the group of participating licensees is presented. The various workshops and evaluation questionnaires are discussed, and detailed findings are presented. 7 refs
Blood Pressure and Visit-to-Visit Blood Pressure Variability among Individuals with Primary Proteinuric Glomerulopathies
Hypertension and blood pressure variability (BPV; SD and average real variability) in primary proteinuric glomerulopathies are not well described. Data were from 433 participants in the NEPTUNE (Nephrotic Syndrome Study Network). Hypertensive BP status was defined as previous history of hypertension or BP ≥140/90 mm Hg for adults/≥95th percentile for children at baseline. BPV was measured in participants with ≥3 visits in the first year. Two-hundred ninety-six adults (43 years [interquartile range, 32-57.8 years], 61.5% male) and 147 children (11 years [interquartile range, 5-14 years], 57.8% male) were evaluated. At baseline, 64.8% of adults and 46.9% of children were hypertensive. Histological diagnosis was associated with hypertensive status in adults (P=0.036). In adults, hypertensive status was associated with lower hazard of complete remission (hazard ratio, 0.36; 95% confidence interval, 0.19-0.68) and greater hazard of achieving the composite end point (end-stage renal disease or estimated glomerular filtration rate decline >40%; hazard ratio, 4.1; 95% confidence interval, 1.4-12). Greater systolic and diastolic SD and average real variability were also associated with greater hazard of reaching the composite end point in adults (all P<0.01). In children, greater BPV was an independent predictor of composite end point (determined by systolic SD and average real variability) and complete remission (determined by systolic and diastolic average real variability; all P<0.05). Hypertensive status was common among adults and children enrolled in NEPTUNE. Differences in hypertensive status prevalence, BPV, and treatment were found by age and histological diagnosis. In addition, hypertensive status and greater BPV were associated with poorer clinical outcomes
Neutralizing antibody vaccine for pandemic and pre-emergent coronaviruses
Betacoronaviruses (betaCoVs) caused the severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) outbreaks, and the SARS-CoV-2 pandemic1–4. Vaccines that elicit protective immunity against SARS-CoV-2 and betaCoVs circulating in animals have the potential to prevent future betaCoV pandemics. Here, we show that macaque immunization with a multimeric SARS-CoV-2 receptor binding domain (RBD) nanoparticle adjuvanted with 3M-052/Alum elicited cross-neutralizing antibody (cross-nAb) responses against batCoVs, SARS-CoV-1, SARS-CoV-2, and SARS-CoV-2 variants B.1.1.7, P.1, and B.1.351. Nanoparticle vaccination resulted in a SARS-CoV-2 reciprocal geometric mean neutralization ID50 titer of 47,216, and protection against SARS-CoV-2 in macaque upper and lower respiratory tracts. Importantly, nucleoside-modified mRNA encoding a stabilized transmembrane spike or monomeric RBD also induced SARS-CoV-1 and batCoV cross-nAbs, albeit at lower titers. These results demonstrate current mRNA vaccines may provide some protection from future zoonotic betaCoV outbreaks, and provide a platform for further development of pan-betaCoV vaccines
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Application of a structured light source for surface mapping in the Fernald K-65 silos
Short communication
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Strange hadronic matter
In an extended mean field theory, there is found a large class of bound multi-strange objects, formed from combinations of (p,n,[Lambda] [Xi][sup 0] [Xi][sup [minus]], baryons, which are stable against strong decay. A maximal binding energy per baryon of E[sub B]/A [approx] [minus]21 MeV, strangeness per baryon of [integral][sub s] [approx] 1--1.2, charge per baryon of [integral][sub q] [approx] [minus]-0.1 to 0.1, and baryon density of 2.5--3 times that of ordinary nuclei are predicted. For A [ge] 6, stable combinations involving only ([Lambda],[Xi][sup 0],[Xi]) hyperons are obtained
Formulation of a process for the planning and management of technology development
Presented at the 1st AIAA ATIO Forum, Los Angeles, CA, October 16-18, 2001.Due to the importance of technology use in
Aerospace systems, the process of technology
development is one of the most important parts of
fielding a new system. Technology development is the
process of creating and managing activities such as
experiments, analysis, and prototyping in order to
reduce the risk associated with the use of a new
technology. While technical risk is addressed by the
activities, the project must be planned and managed so
as to reduce the cost and schedule risk associated with
completing those activities. This study introduces a
process that will assist in the planning and management
of a technology development project and lead to
successful development efforts