Abstract
We present the design and first results of an assembly that enables rare earth barium copper oxide (REBCO) superconducting cables—the VIPER cable in this work—to be tested in the SULTAN ...facility under the simultaneous application of transverse electromechanical loading and axial mechanical strain. The objective is to emulate the loads that a REBCO cable would experience in a three-dimensional coil but in shorter and simpler straight cables, reducing the cost, schedule, and complexity of high-fidelity conductor qualification. The assembly uses two methods for inducing axial strain in the cables. First, hydraulic jacks stretch the assembly and inserted Invar shims lock in up to ∼0.3% axial cable strain on the benchtop at room temperature. Second, the different coefficients of thermal expansion between Invar clamps and the copper cable are exploited to induce an additional ∼0.3% axial strain on the cable when the sample is cooled in the SULTAN test well from room temperature to below 50 K. Finite element analysis modeling shows that the soldered matrix of the VIPER cable transfers approximately 50%–60% of the external cable strain into the REBCO stack. The assembly was successfully employed at SULTAN, enabling two VIPER cables to be cycled 500 times at 382 kN m
−1
transverse electromechanical loads with ∼0.5% mechanical strain on the cable (corresponding to ∼0.3% mechanical strain in the REBCO stacks) demonstrating critical current degradation stabilizing after 30 cycles at less than 5% and providing confidence in VIPER cables under realistic high-field magnet conditions.
The aim of this study was to evaluate clinical parameters and expression patterns of Ki-67, cyclin D1 and p53 in odontogenic keratocysts.
In this study, fifty-three patients with 80 odontogenic ...keratocysts were included. The medical records of these patients were reviewed retrospectively. To elucidate the molecular pathogenesis of the disease, the expression of p53, Ki-67 and cyclin D1 was analyzed using immunohistochemistry.
A total of 53 patients (mean age 38 years) with a median follow-up of 4.2 years (ranging from 4 days to 14.4 years) were evaluated. The rates of recurrence and post-operative complications varied depending on the surgical approach: cystectomy and peripheral ostectomy led to manageable low rates of complications and recurrence frequency. Immunohistochemical evaluation revealed that all lesions were positive for Ki-67 and cyclin D1 expression. The expression of Ki-67 was associated with the degree of inflammation. Cyclin D1 was expressed significantly higher in syndrome-associated keratocystic lesions. In contrast to non-syndromal lesions, all syndromal lesions expressed p53.
This investigation demonstrates that the pathogenesis of syndromal keratocysts appears to differ from sporadic odontogenic keratocysts. Additionally, the primary and recurrent non-syndromal keratocysts have a similar etiology, as no differences in the expression patterns of Ki-67, p53 and cyclin D1 were observed.
Noninvasive prenatal testing and maternal obesity: A review Juul, Laura A.; Hartwig, Tanja S.; Ambye, Louise ...
Acta obstetricia et gynecologica Scandinavica,
June 2020, 2020-Jun, 2020-06-00, 20200601, Letnik:
99, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Noninvasive prenatal testing (NIPT) has become a popular screening test for the most common fetal aneuploidies. The performance of NIPT is affected by several factors including maternal obesity, ...which results in a greater rate of no‐calls for obese pregnant women. Guidelines regarding NIPT in prenatal screening have been published, but with few and divergent recommendations on the issue. We aimed to review the medical literature, guidelines from scientific societies and information material from commercial NIPT providers on no‐calls and maternal obesity. We systematically identified medical literature and guidelines from scientific societies using the database MEDLINE. Information material from commercial NIPT providers was found via a systematic search on Google.com. Nine medical studies investigating the association between maternal obesity and NIPT no‐calls were included. They all showed the same trend: increasing no‐call rate with increasing maternal obesity. The no‐call rate ranged from 0% to 4.2% for women with body mass index (BMI) 18.5‐24.9 and from 5.4% to 70.1% for women BMI ≥40. We identified 17 scientific societies with guidelines and 13 commercial NIPT providers. All were checked for information material on no‐calls and maternal obesity. To allow comparison, all guidelines were examined to answer the same three predefined questions. Of the 17 included scientific societies, 13 (76.5%) mentioned the association between maternal obesity and NIPT no‐calls, two (11.8%) specified weight limits and three (17.6%) advised against NIPT for severely obese pregnant women. None of the 13 commercial NIPT providers provided specific recommendations, but four (30.8%) cite maternal obesity as a potential cause for a no‐call. Because of the increasing number of patients in this group, we advocate updated recommendations to guide decision making in prenatal screening for obese pregnant women.
We have established an open source platform for non-invasive prenatal testing (NIPT) based on massively parallel whole-genome sequencing in a public setting. The objective of this study was to ...investigate factors of importance for correct interpretation of NIPT results to ensure a high sensitivity and specificity.
This investigation is a retrospective case-control study performed in a public NIPT center. The study included 108 aneuploid cases and 165 euploid controls. MPS was performed on circulating cell-free DNA in maternal blood. The pipeline included automated library preparation and sequencing on a HiSeq1500 (Illumina). The software programmes WISECONDOR and SeqFF were used for data analysis of aneuploidy status and fetal fraction of cell-free DNA, respectively. Lower limit of fetal fraction for aneuploidy testing was 0.02.
We identified four false negative aneuploidy cases of which two were explained by a vanishing twin. The number of no-call cases due to low fetal fraction was 8 out of 273 (2.9%). The sensitivity and specificity, when no-calls and vanished twins were excluded, were 100% and 99.5% for T21, 91% and 99.2% for T18, and 100% and 99.6% for T13. By multiple regression analysis we found a significant association between fetal fraction and gestational age, maternal BMI and ART treatment.
With a non-commercial open source NIPT set-up having the same high test-performance as reported by large private laboratories, we show that fetal fraction, a vanishing twin, BMI, gestational age and ART treatment are important factors in the interpretation of NIPT results.
High-temperature superconducting-slotted cables, including the VIPER cable, are being investigated as possible candidates for winding the toroidal field coils of compact nuclear fusion machines, such ...as ARC. The higher performance of HTS materials in terms of magnetic fields and currents allows them to reduce their size compared to machines based on Nb alloys and compounds. However, compactness also means a closer interaction between the plasma products and the coils, creating new technological challenges to be faced. Among the others, the thermal effects induced on the superconducting materials by direct particles (i.e., neutrons), secondary particles and gamma-ray heating, will be stronger than for low-field larger machines and must be quantified. In this paper, a detailed thermo-magnetic model is built up using the software COMSOL Multiphysics to simulate the consequences of the D-T plasma operation products on the first turn of a toroidal field coil of the ARC preliminary machine design. The irradiation-induced heat load on the (RE)Ba 2 Cu 3 O 7-δ tapes, computed via Monte Carlo simulations, is used as input for the thermal analysis of the VIPER cable. At the same time, a homogenized T-A formulation is developed for checking the performance reduction in the current/field operating conditions.
The SPARC Toroidal Field Model Coil Program Hartwig, Zachary S.; Vieira, Rui F.; Dunn, Darby ...
IEEE transactions on applied superconductivity,
03/2024, Letnik:
34, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The SPARC Toroidal Field Model Coil (TFMC) Program was a three-year effort between 2018 and 2021 that developed novel rare earth barium copper oxide (REBCO) superconductor technologies and then ...successfully utilized these technologies to design, build, and test a first-in-class, high-field (∼20 T), representative-scale (∼3 m) superconducting toroidal field (TF) coil. The program was executed jointly by the MIT Plasma Science and Fusion Center (PSFC) and Commonwealth Fusion Systems (CFS) as a technology enabler of the superconducting high-field pathway to fusion energy, and, in particular, as a risk retirement program for the no insulation (NI) TF magnet in the SPARC net-energy fusion tokamak. The TFMC achieved its programmatic goal of experimentally demonstrating a large-scale high-field REBCO magnet, achieving 20.1 T peak field-on-conductor with 40.5 kA of terminal current, 815 kN/m of Lorentz loading on the REBCO stacks, and almost 1 GPa of mechanical stress accommodated by the structural case. Fifteen internal demountable pancake-to-pancake joints operated in the 0.5 to 2.0 nΩ range at 20 K and in magnetic fields up to 12 T. The dc and ac electromagnetic performance of the magnet predicted by new advances in high-fidelity computational models was confirmed in two test campaigns while the parallel, single-pass, pressure-vessel style coolant scheme capable of large heat removal was validated. In the test facility, a feeder system composed of REBCO current leads and cables was experimentally qualified up to 50 kA, and a liquid-free cryocooler-based helium cryogenic system provided 600 W of cooling power at 20 K with mass flow rates up to 70 g/s at a maximum design pressure of 2 MPa for the test campaigns. Finally, the feasibility of using passive, self-protection against a quench in a fusion-scale NI TF coil was experimentally assessed. While the TFMC was intentionally not optimized for quench resiliency-and suffered localized thermal damage in response to an intentional open-circuit quench at 31.5 kA terminal current-the extensive data and validated models that it produced represent a critical step towards this important objective.
Abstract
The benefits of operating fusion devices, such as tokamaks and stellarators, at high fields make high-temperature superconducting magnets necessary to realize a compact fusion power system. ...Superconducting stellarators, such as W7-X, have used standard low-temperature superconductor technology niobium-titanium. ARPA-E has recently funded a two-year project led by the startup Type One Energy and involving the Fusion Technology Institute at the University of Wisconsin-Madison, the Plasma Science to design and fabricate the first non-planar high-temperature superconductor (HTS) rare-earth barium copper oxide (REBCO) coil for a high-field stellarator based on the SPARC tokamak’s VIPER cable concept. The design consists of a 1.5-turn non-planar REBCO coil supported by a pair of 3D printed stainless steel radial plates. The ultimate goals of the project are to determine if commercial REBCO tapes and additive manufacturing can be used to fabricate high field (
⩾
10
T
) non-planar coils with tight bending radii (
≃
100
m
m
) and with a degradation of the critical current smaller than 20% with respect to the expected performance. In this work we present numerical analysis for non-planar coils (critical current, magnetic field map, Lorentz forces and quench aspects) at the operating conditions of 77 K and 20 K and the fabrication and testing in liquid nitrogen (77 K) of the first two non-planar demonstrators for stellarators based on a VIPER cable. The first demonstrator is a short
NO
n-planar
V
IP
E
R cab
L
e (cable demonstrator at which we will refer to as
NOVEL
) equipped with 100 HTS REBCO tapes and with a critical current of 5700 A at 77 K (self-field); the second is a
M
ult
I
ple turns (1.5-turns)
NO
n-pl
AN
ar coil (coil demonstrator at which we will refer to as
MINOAN
) equipped with 30 HTS tapes and with a critical current of 2100 A at 77 K (self-field). Both demonstrators were tested at 77 K (liquid nitrogen bath) and the results showed that—even after being bent into non-planar shapes with bend radii
≃
100
m
m
—the degradation of the critical current
I
c
was within 15%, meeting the expected goals of the project.
From June 2019 to July 2021, the MIT Plasma Science and Fusion Center, in collaboration with Commonwealth Fusions Systems, designed, built, and commissioned a test facility at the Massachusetts ...Institute of Technology to evaluate the performance of a rare-earth-yttrium-barium-copper-oxide-based, 2.9-m tall, 1.9-m wide Toroidal Field Model Coil (TFMC) for the SPARC tokamak. This article presents the facility's supercritical helium (SHe) circulation system design and measured performance. The facility employed a forced-flow SHe circulation loop cooled by cryocoolers to provide a nominal cooling power of 600 W at 20 K and up to 70 g/s SHe flow to the TFMC at an absolute pressure of 20 bar. The reliance on cryocoolers as the facility's cooling source was an ideal arrangement. Procurement costs were modest, acquisition time was reasonable, and seating requirements were minimal. A steady improvement in cryocooler design provided a simple-to-use system with sufficient cooling capacity for our needs. Extensive, closed-loop analyses were performed both to support this procurement and to finalize the overall design of the SHe cooling circuit. The SHe system worked reliably, permitting flexible operation of the TFMC test facility under all working conditions.
— Aims: This study examined the possibility of using hair samples other than scalp hair for analysis of fatty acid ethyl esters (FAEE) as markers for alcohol misuse. Methods: Samples of scalp and ...pubic hair and, if available, axillary, beard and body hair of one teetotaller, five moderate social drinkers and 22 fatalities were analysed for FAEE by head-space solid-phase microextraction and gas chromatography–mass spectrometry. The sum of the concentrations of ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate (CFAEE) in the hair samples was compared with information about the drinking behaviour of the individuals. Results: Although there were large differences in the analyte concentrations in hair from different sites in the same individual, cases of chronic excessive alcohol consumption were characterized by CFAEE > 1.0 ng/mg in almost all samples. Conclusion: FAEE concentrations in hair other than scalp hair can be used as markers of chronic alcohol misuse.
This paper presents design, fabrication, and operational results for a novel pair of binary Current Leads (CLs). The CLs were purpose built for the SPARC Toroidal Field Model Coil (TFMC) Test ...Facility at the MIT Plasma Science and Fusion Center (PSFC). The CLs operate stably at current ramp rates up to 50 kA/s and steady-state currents of 50 kA from ambient temperature power supplies to the facility's 20 K test environment. The CLs have three main sections: an upper copper heat exchanger (HEX) cooled with gas nitrogen (GN2) which connects to room temperature power supply (PS); a central liquid nitrogen (LN2) boiling chamber (BC) which vents into the HEX; and a lower Rare Earth Yttrium Barium Copper Oxide (REBCO) Section. The CLs have three distinguishing features: the BCs high surface area maintains <1 K temperature difference between their surfaces and the nucleate boiling LN2 within; each REBCO section is composed of six parallel "petals" that were individually qualified prior to installation; indium seals were used to simultaneously provide electrical continuity and hermetic sealing which enabled fabrication without need for braze or electron beam welding qualification processes. Additionally, the CLs can reduce the LN2 boiling pressure and thus temperature which significantly improves the temperature margins within the REBCO Section. The CLs were designed and built within 1.5 years and used successfully to deliver 40.5 kA of current to the SPARC TFMC. Since then they have been thermally cycled over 10 times and operated at both 1 atm and 0.65 atm.
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