177 results on '"TBR"'
Search Results
2. Synthesis, preclinical assessment, and first-in-human study of [18F]d4-FET for brain tumor imaging
- Author
-
Hou, Lu, Chen, Zhiyong, Chen, Fanfan, Sheng, Lianghe, Ye, Weijian, Dai, Yingchu, Guo, Xiaoyu, Dong, Chenchen, Li, Guocong, Liao, Kai, Li, Yinlong, Ma, Jie, Wei, Huiyi, Ran, Wenqing, Shang, Jingjie, Ling, Xueying, Patel, Jimmy S., Liang, Steven H., Xu, Hao, and Wang, Lu
- Published
- 2024
- Full Text
- View/download PDF
3. QEEG indices in traumatic brain injury - insights from the CAPTAIN RTMS trial.
- Author
-
Roșu, Olivia Verișezan, Chira, Diana, Chelaru, Vlad-Florin, Dăbală, Diana Chertic, Popa, Livia Livinț, Buruiană, Ana-Maria, and Mureșanu, Fior Dafin
- Abstract
This secondary analysis of the CAPTAIN-RTMS trial data focused on the significance of quantitative electroencephalography (qEEG) indices as indicators of recovery in patients with traumatic brain injury (TBI). By focusing on the delta alpha ratio (DAR), delta theta/alpha beta ratio (DTABR), and theta beta ratio (TBR), this study explored the shifts in brainwave activity as a response to an integrative treatment regimen of repetitive transcranial magnetic stimulation (rTMS) combined with the neurotrophic agent Cerebrolysin. Findings revealed significant increases in DAR and DTABR, suggesting changes in neurophysiological dynamics after treatment. However, variations in TBR were inconclusive in providing clear electrophysiological insights. These results indicate that further research is necessary to describe and understand the underlying mechanisms of brain recovery and to develop refined treatment frameworks for patients with TBI. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Challenging the Diagnostic Value of Theta/Beta Ratio: Insights From an EEG Subtyping Meta-Analytical Approach in ADHD
- Author
-
Boxum, Marit, Voetterl, Helena, van Dijk, Hanneke, Gordon, Evian, DeBeus, Roger, Arnold, L. Eugene, and Arns, Martijn
- Published
- 2024
- Full Text
- View/download PDF
5. Main Nuclear Responses of the DEMO Tokamak with Different In-Vessel Component Configurations.
- Author
-
Park, Jin Hun and Pereslavtsev, Pavel
- Subjects
FUSION reactor blankets ,TOKAMAKS ,NUCLEAR energy ,GEOMETRIC modeling ,NEUTRAL beams ,DATA libraries - Abstract
Research and development of the DEMOnstration power plant (DEMO) breeder blanket (BB) has been performed in recent years based on a predefined DEMO tritium breeding ratio (TBR) requirement, which determines a loss of wall surface due to non-breeding in-vessel components (IVCs) which consume plasma-facing wall surface and do not contribute to the breeding of tritium. The integration of different IVCs, such as plasma limiters, neutral beam injectors, electron cyclotron launchers and diagnostic systems, requires cut-outs in the BB, resulting in a loss of the breeder blanket volume, TBR and power generation, respectively. The neutronic analyses presented here have the goal of providing an assessment of the TBR losses associated with each IVC. Previously performed studies on this topic were carried out with simplified, homogenized BB geometry models. To address the effect of the detailed heterogeneous structure of the BBs on the TBR losses due to the inclusion of the IVCs in the tokamak, a series of blanket geometry models were developed for integration in the latest DEMO base model. The assessment was performed for both types of BBs currently developed within the EUROfusion project, the helium-cooled pebble bed (HCPB) and water-cooled lead–lithium (WCLL) concepts, and for the water-cooled lead and ceramic breeder (WLCB) hybrid BB concept. The neutronic simulations were performed using the MCNP6.2 Monte Carlo code with the Joint Evaluated Fission and Fusion File (JEFF) 3.3 data library. For each BB concept, a 22.5° toroidal sector of the DEMO tokamak was developed to assess the TBR and nuclear power generation in the breeder blankets. For the geometry models with the breeder blanket space filled only with blankets without considering IVCs, the results of the TBR calculations were 1.173, 1.150 and 1.140 for the HCPB, WCLL and WLCB BB concepts, respectively. The TBR impact of all IVCs and the losses of the power generation were estimated as a superposition of the individual effects. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Neutronic Assessments towards a Novel First Wall Design for a Stellarator Fusion Reactor with Dual Coolant Lithium Lead Breeding Blanket.
- Author
-
Sosa, David and Palermo, Iole
- Subjects
- *
FUSION reactor blankets , *TRITIUM , *FUSION reactors , *WALL design & construction , *LIQUID metals , *COOLANTS , *THERMAL shielding - Abstract
The Stellarator Power Plant Studies Prospective R&D Work Package in the Eurofusion Programme was settled to bring the stellarator engineering to maturity, so that stellarators and particularly the HELIAS (HELical-axis Advanced Stellarator) configuration could be a possible alternative to tokamaks. However, its complex geometry makes designing a Breeding Blanket (BB) that fully satisfies the requirements for such a HELIAS configuration, which is a difficult task. Taking advantage of the acquired experience in BB design for DEMO tokamak, CIEMAT is leading the development of a Dual Coolant Lithium Lead (DCLL) BB for a HELIAS configuration. To answer the specific HELIAS challenges, new and advanced solutions have been proposed, such as the use of fully detached First Wall (FW) based on liquid metal Capillary Porous Systems (CPS). The proposed solutions have been studied in a simplified 1D model that can help to estimate the relative variations in Tritium Breeding Ratio (TBR) and displacement per atom (dpa) to verify their effectiveness in simplifying the BB integration and improving the machine availability while keeping the main BB nuclear functions (i.e., tritium breeding, heat extraction and shielding). This preliminary study demonstrates that the use of FW CPS would drastically reduce the radiation damage received by the blanket by 29% in some of the selected configurations along with a small decrease of 4.9% in TBR. This could even be improved to just a 3.8% TBR reduction by using a graphite reflector. Such an impact on the TBR is considered affordable, and the results presented, although preliminary in essence, have shown the existence of margins for further development of the FW CPS concept for HELIAS, as they have been not found, at least to date, to be significant showstoppers for the use of this technological solution. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. Main Nuclear Responses of the DEMO Tokamak with Different In-Vessel Component Configurations
- Author
-
Jin Hun Park and Pavel Pereslavtsev
- Subjects
DEMO ,TBR ,breeder blanket ,Monte Carlo ,MCNP ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Research and development of the DEMOnstration power plant (DEMO) breeder blanket (BB) has been performed in recent years based on a predefined DEMO tritium breeding ratio (TBR) requirement, which determines a loss of wall surface due to non-breeding in-vessel components (IVCs) which consume plasma-facing wall surface and do not contribute to the breeding of tritium. The integration of different IVCs, such as plasma limiters, neutral beam injectors, electron cyclotron launchers and diagnostic systems, requires cut-outs in the BB, resulting in a loss of the breeder blanket volume, TBR and power generation, respectively. The neutronic analyses presented here have the goal of providing an assessment of the TBR losses associated with each IVC. Previously performed studies on this topic were carried out with simplified, homogenized BB geometry models. To address the effect of the detailed heterogeneous structure of the BBs on the TBR losses due to the inclusion of the IVCs in the tokamak, a series of blanket geometry models were developed for integration in the latest DEMO base model. The assessment was performed for both types of BBs currently developed within the EUROfusion project, the helium-cooled pebble bed (HCPB) and water-cooled lead–lithium (WCLL) concepts, and for the water-cooled lead and ceramic breeder (WLCB) hybrid BB concept. The neutronic simulations were performed using the MCNP6.2 Monte Carlo code with the Joint Evaluated Fission and Fusion File (JEFF) 3.3 data library. For each BB concept, a 22.5° toroidal sector of the DEMO tokamak was developed to assess the TBR and nuclear power generation in the breeder blankets. For the geometry models with the breeder blanket space filled only with blankets without considering IVCs, the results of the TBR calculations were 1.173, 1.150 and 1.140 for the HCPB, WCLL and WLCB BB concepts, respectively. The TBR impact of all IVCs and the losses of the power generation were estimated as a superposition of the individual effects.
- Published
- 2024
- Full Text
- View/download PDF
8. Incorporating the Benefits of Geosynthetic into MEPDG.
- Author
-
Abu-Farsakh, Murad, Zadehmohamad, Mehdi, and Voyiadjis, George Z.
- Subjects
FLEXIBLE pavements ,GEOGRIDS ,TRANSFER functions ,GEOTEXTILES ,GEOSYNTHETICS ,SYNTHETIC apertures - Abstract
One of the most effective ways to increase the longevity of pavement structures is through the integration of geosynthetic reinforcement. Geosynthetics are synthetic materials such as geotextiles, geogrids, or geocomposites that are added to the interface between the subgrade and the base layer of a pavement structure. To evaluate the effect of various parameters on the structural benefits of geosynthetic reinforcement on the pavement structure of low-volume traffic flexible pavements, a finite element (FE) study was performed using the ABAQUS program. These parameters included the geosynthetic type, geosynthetic tensile stiffness, subgrade stiffness, and base thickness. The FE rutting curves for the 100 cycles were calibrated using the mechanistic–empirical (M-E) transfer functions, which were then used to calculate the long-term rutting curves. The traffic benefit ratio (TBR) was initially calculated based on the calibrated rutting curves for each pavement layer. The calculated TBRs were then used as an input in AASHTOWare to compute the base effective resilient modulus (M
R-eff ) and the factor of base course reduction (BCR). The results showed that adding one layer of geosynthetics enhanced the rutting performance of pavement structures significantly (up to 8.9 in TBR, 322% in MR-eff , and 64% in BCR). Geogrids showed higher benefits than geotextiles due to the interlocking between base aggregates and geogrid aperture. The values of TBR, MR-eff , and BCR increase with the increasing tensile stiffness of the geosynthetics and the rutting target and with the decreasing subgrade stiffness. The results also demonstrated peak values of TBR, MR-eff , and BCR for a base thickness of 25.4 cm. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
9. EEG‐biomarker theta/beta ratio and attentional quotients in adults who stutter: An electrophysiological and behavioral study.
- Author
-
Poormohammad, Ahmad, Pourrahimi, Ali Mohammad, Fathi, Mazyar, Sardari, Sara, Razavi, Mahdiye Sarrafe, Bahrasemani, Mohammad Karimi, Mozaffary, Anusheh Mosanen, and Mazhari, Shahrzad
- Subjects
- *
BECK Anxiety Inventory , *AUDITORY selective attention , *STUTTERING , *ELECTROPHYSIOLOGY - Abstract
Introduction: There is increasing evidence that connects developmental stuttering to attention. However, findings have represented contradiction. Therefore, this study was conducted to investigate the possible relationship between stuttering and attention in resting and undertask conditions. Methods: In a cross‐sectional study, 26 right‐handed AWS (adults who stutter) and 25 matched fluent speakers were enrolled. Demographic data were collected, and the Beck anxiety inventory (BAI) was filled out for all participants. Then, QEEG was conducted, followed by IVA2. CPT test for all subjects. Finally, data were analyzed using SPSS software version 16. Results: AWS indicated significantly weaker auditory focus attention in the task (p =.02) than the control group, while a similar resting‐state EEG marker of attention was found between groups (p >.05). Moreover, attention was not correlated between the two conditions (p >.05). Conclusion: The EEG marker of attention did not necessarily designate the attentional performance of AWS under the task. Furthermore, attentional skills could be considered in the assessment and therapeutic programs of at least some groups of AWS. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
10. Synthesis, preclinical assessment, and first-in-human study of [18F]<italic>d</italic>4-FET for brain tumor imaging.
- Author
-
Hou, Lu, Chen, Zhiyong, Chen, Fanfan, Sheng, Lianghe, Ye, Weijian, Dai, Yingchu, Guo, Xiaoyu, Dong, Chenchen, Li, Guocong, Liao, Kai, Li, Yinlong, Ma, Jie, Wei, Huiyi, Ran, Wenqing, Shang, Jingjie, Ling, Xueying, Patel, Jimmy S., Liang, Steven H., Xu, Hao, and Wang, Lu
- Subjects
- *
POSITRON emission tomography , *RADIOCHEMICAL purification , *RADIATION dosimetry , *KRA , *BRAIN tumors , *RADIOACTIVE tracers - Abstract
Purpose: Tumor-to-background ratio (TBR) is a critical metric in oncologic PET imaging. This study aims to enhance the TBR of [18F]FET in brain tumor imaging by substituting deuterium ("D") for hydrogen ("H"), thereby improving the diagnostic sensitivity and accuracy.[18F]
d 4-FET was synthesised by two automated radiochemistry modules. Biodistribution studies and imaging efficacy were evaluated in vivo and ex vivo in rodent models, while metabolic stability and radiation dosimetry were assessed in non-human primates. Additionally, preliminary imaging evaluations were carried out in five brain tumor patients: three glioma patients underwent imaging with both [18F]d 4-FET and [18F]FET, and two patients with brain metastases were imaged using [18F]d 4-FET and [18F]FDG.[18F]d 4-FET demonstrated high radiochemical purity and yield. PET/MRI in rodent models demonstrated superior TBR for [18F]d 4-FET compared to [18F]FET, and autoradiography showed tumor margins that correlated well with pathological extents. Studies in cynomolgus monkeys indicated comparable in vivo stability and effective dose with [18F]FET. In glioma patients, [18F]d 4-FET showed enhanced TBR, while in patients with brain metastases, [18F]d 4-FET displayed superior lesion delineation compared to [18F]FDG, especially in smaller metastatic sites.We successfully synthesized the novel PET radiotracer [18F]d 4-FET, which retains the advantageous properties of [18F]FET while potentially enhancing TBR for glioma imaging. Preliminary studies indicate excellent stability, efficacy, and sensitivity of [18F]d 4-FET, suggesting its potential in clinical evaluations of brain tumors.ChiCTR2400081576, registration date: 2024–03-05, https://www.chictr.org.cn/bin/project/edit?pid=206162Methods: Tumor-to-background ratio (TBR) is a critical metric in oncologic PET imaging. This study aims to enhance the TBR of [18F]FET in brain tumor imaging by substituting deuterium ("D") for hydrogen ("H"), thereby improving the diagnostic sensitivity and accuracy.[18F]d 4-FET was synthesised by two automated radiochemistry modules. Biodistribution studies and imaging efficacy were evaluated in vivo and ex vivo in rodent models, while metabolic stability and radiation dosimetry were assessed in non-human primates. Additionally, preliminary imaging evaluations were carried out in five brain tumor patients: three glioma patients underwent imaging with both [18F]d 4-FET and [18F]FET, and two patients with brain metastases were imaged using [18F]d 4-FET and [18F]FDG.[18F]d 4-FET demonstrated high radiochemical purity and yield. PET/MRI in rodent models demonstrated superior TBR for [18F]d 4-FET compared to [18F]FET, and autoradiography showed tumor margins that correlated well with pathological extents. Studies in cynomolgus monkeys indicated comparable in vivo stability and effective dose with [18F]FET. In glioma patients, [18F]d 4-FET showed enhanced TBR, while in patients with brain metastases, [18F]d 4-FET displayed superior lesion delineation compared to [18F]FDG, especially in smaller metastatic sites.We successfully synthesized the novel PET radiotracer [18F]d 4-FET, which retains the advantageous properties of [18F]FET while potentially enhancing TBR for glioma imaging. Preliminary studies indicate excellent stability, efficacy, and sensitivity of [18F]d 4-FET, suggesting its potential in clinical evaluations of brain tumors.ChiCTR2400081576, registration date: 2024–03-05, https://www.chictr.org.cn/bin/project/edit?pid=206162Results: Tumor-to-background ratio (TBR) is a critical metric in oncologic PET imaging. This study aims to enhance the TBR of [18F]FET in brain tumor imaging by substituting deuterium ("D") for hydrogen ("H"), thereby improving the diagnostic sensitivity and accuracy.[18F]d 4-FET was synthesised by two automated radiochemistry modules. Biodistribution studies and imaging efficacy were evaluated in vivo and ex vivo in rodent models, while metabolic stability and radiation dosimetry were assessed in non-human primates. Additionally, preliminary imaging evaluations were carried out in five brain tumor patients: three glioma patients underwent imaging with both [18F]d 4-FET and [18F]FET, and two patients with brain metastases were imaged using [18F]d 4-FET and [18F]FDG.[18F]d 4-FET demonstrated high radiochemical purity and yield. PET/MRI in rodent models demonstrated superior TBR for [18F]d 4-FET compared to [18F]FET, and autoradiography showed tumor margins that correlated well with pathological extents. Studies in cynomolgus monkeys indicated comparable in vivo stability and effective dose with [18F]FET. In glioma patients, [18F]d 4-FET showed enhanced TBR, while in patients with brain metastases, [18F]d 4-FET displayed superior lesion delineation compared to [18F]FDG, especially in smaller metastatic sites.We successfully synthesized the novel PET radiotracer [18F]d 4-FET, which retains the advantageous properties of [18F]FET while potentially enhancing TBR for glioma imaging. Preliminary studies indicate excellent stability, efficacy, and sensitivity of [18F]d 4-FET, suggesting its potential in clinical evaluations of brain tumors.ChiCTR2400081576, registration date: 2024–03-05, https://www.chictr.org.cn/bin/project/edit?pid=206162Conclusion: Tumor-to-background ratio (TBR) is a critical metric in oncologic PET imaging. This study aims to enhance the TBR of [18F]FET in brain tumor imaging by substituting deuterium ("D") for hydrogen ("H"), thereby improving the diagnostic sensitivity and accuracy.[18F]d 4-FET was synthesised by two automated radiochemistry modules. Biodistribution studies and imaging efficacy were evaluated in vivo and ex vivo in rodent models, while metabolic stability and radiation dosimetry were assessed in non-human primates. Additionally, preliminary imaging evaluations were carried out in five brain tumor patients: three glioma patients underwent imaging with both [18F]d 4-FET and [18F]FET, and two patients with brain metastases were imaged using [18F]d 4-FET and [18F]FDG.[18F]d 4-FET demonstrated high radiochemical purity and yield. PET/MRI in rodent models demonstrated superior TBR for [18F]d 4-FET compared to [18F]FET, and autoradiography showed tumor margins that correlated well with pathological extents. Studies in cynomolgus monkeys indicated comparable in vivo stability and effective dose with [18F]FET. In glioma patients, [18F]d 4-FET showed enhanced TBR, while in patients with brain metastases, [18F]d 4-FET displayed superior lesion delineation compared to [18F]FDG, especially in smaller metastatic sites.We successfully synthesized the novel PET radiotracer [18F]d 4-FET, which retains the advantageous properties of [18F]FET while potentially enhancing TBR for glioma imaging. Preliminary studies indicate excellent stability, efficacy, and sensitivity of [18F]d 4-FET, suggesting its potential in clinical evaluations of brain tumors.ChiCTR2400081576, registration date: 2024–03-05, https://www.chictr.org.cn/bin/project/edit?pid=206162Trial registration: Tumor-to-background ratio (TBR) is a critical metric in oncologic PET imaging. This study aims to enhance the TBR of [18F]FET in brain tumor imaging by substituting deuterium ("D") for hydrogen ("H"), thereby improving the diagnostic sensitivity and accuracy.[18F]d 4-FET was synthesised by two automated radiochemistry modules. Biodistribution studies and imaging efficacy were evaluated in vivo and ex vivo in rodent models, while metabolic stability and radiation dosimetry were assessed in non-human primates. Additionally, preliminary imaging evaluations were carried out in five brain tumor patients: three glioma patients underwent imaging with both [18F]d 4-FET and [18F]FET, and two patients with brain metastases were imaged using [18F]d 4-FET and [18F]FDG.[18F]d 4-FET demonstrated high radiochemical purity and yield. PET/MRI in rodent models demonstrated superior TBR for [18F]d 4-FET compared to [18F]FET, and autoradiography showed tumor margins that correlated well with pathological extents. Studies in cynomolgus monkeys indicated comparable in vivo stability and effective dose with [18F]FET. In glioma patients, [18F]d 4-FET showed enhanced TBR, while in patients with brain metastases, [18F]d 4-FET displayed superior lesion delineation compared to [18F]FDG, especially in smaller metastatic sites.We successfully synthesized the novel PET radiotracer [18F]d 4-FET, which retains the advantageous properties of [18F]FET while potentially enhancing TBR for glioma imaging. Preliminary studies indicate excellent stability, efficacy, and sensitivity of [18F]d 4-FET, suggesting its potential in clinical evaluations of brain tumors.ChiCTR2400081576, registration date: 2024–03-05, https://www.chictr.org.cn/bin/project/edit?pid=206162 [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
11. Compact fusion blanket using plasma facing liquid Li-LiH walls and Pb pebbles.
- Author
-
Prost, Victor, Ogier-Collin, Sabine, and Volpe, Francesco A.
- Subjects
- *
FUSION reactor blankets , *FUSION reactors , *TRITIUM , *THERMAL shielding , *LIQUID metals , *LEAD - Abstract
Liquid plasma facing walls allow for increased neutron-wall loading expanding the design space of fusion power-plants and experimental devices towards compact high-field reactors. This study presents the design of a compact radial build blanket for fusion devices composed of variable quantities of Lead (Pb) and Lithium-Lithium Hydride (Li-LiH). A tank-like cylindrical neutronic model of the early design of the stellarator reactor proposed by Renaissance Fusion is implemented in OpenMC (neutron transport and dose rate analyses). The reactor's radial build composition and blanket layer thicknesses are varied to fulfill the requirements on tritium breeding ratio (TBR), nuclear heat extraction, radiation shielding (for the coils, internal structures and external environment) for a stellarator-based power-plant. The analyses suggest that a radial build lower than a meter thick between the plasma and coils would be sufficient to allow for a TBR ∼ 1.60, an energy multiplication factor of ∼ 1.07, to capture ≥ 90% of the nuclear heat, limit the neutron fluence at the coils below 1019 n/cm2, and limit the structural damage on the liquid metal vessel and magnet structure. In particular, a blanket composed of 32 cm of Pb and Li-LiH, 54 cm of a heavy metal hydride such as vanadium hydride (VH 2), along with a 1.3 m of concrete bioshield, would minimize the radial build of the stellarator reactor while fulfilling tritium breeding, shielding and heat extraction requirements. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. EEG‐biomarker theta/beta ratio and attentional quotients in adults who stutter: An electrophysiological and behavioral study
- Author
-
Ahmad Poormohammad, Ali Mohammad Pourrahimi, Mazyar Fathi, Sara Sardari, Mahdiye Sarrafe Razavi, Mohammad Karimi Bahrasemani, Anusheh Mosanen Mozaffary, and Shahrzad Mazhari
- Subjects
attention ,AWS ,IVA ,TBR ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Abstract Introduction There is increasing evidence that connects developmental stuttering to attention. However, findings have represented contradiction. Therefore, this study was conducted to investigate the possible relationship between stuttering and attention in resting and undertask conditions. Methods In a cross‐sectional study, 26 right‐handed AWS (adults who stutter) and 25 matched fluent speakers were enrolled. Demographic data were collected, and the Beck anxiety inventory (BAI) was filled out for all participants. Then, QEEG was conducted, followed by IVA2. CPT test for all subjects. Finally, data were analyzed using SPSS software version 16. Results AWS indicated significantly weaker auditory focus attention in the task (p = .02) than the control group, while a similar resting‐state EEG marker of attention was found between groups (p > .05). Moreover, attention was not correlated between the two conditions (p > .05). Conclusion The EEG marker of attention did not necessarily designate the attentional performance of AWS under the task. Furthermore, attentional skills could be considered in the assessment and therapeutic programs of at least some groups of AWS.
- Published
- 2023
- Full Text
- View/download PDF
13. Desempenho regional dos alunos brasileiros de engenharia no Enade (2005 a 2017) com uso da taxonomia revisada de bloom (TBR)
- Author
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Leila Dainara Venceslau Santos de Gusmao
- Subjects
território ,tbr ,brasil ,engenharia ,enade ,inep ,Industries. Land use. Labor ,HD28-9999 ,Social sciences (General) ,H1-99 - Abstract
Objetivos: Este artigo tem o objetivo de analisar o desempenho regional dos cursos de Engenharia de Produção das instituições brasileiras de ensino superior brasileiras que participaram do Exame Nacional de Desempenho dos Estudantes (Enade) nos anos de 2005, 2008, 2011, 2014 e 2017. Metodologia: devido a dificuldades de coleta de dados mais recentes de Enade, se optou por manter dados estáveis e completos. Limitação: devido a dificuldades em coletar dados mais recentes do Enade, optou-se por manter os dados estáveis e completos. Resultados: Os resultados realçam desenpenhos inferiores em determinadas regiões do território brasileiro. Uma efetiva política de avaliação proporia ações para mudança do quadro que parece se perpetuar por todos os instrumentos avaliativos pelos quais as instituições da região Norte foram avaliadas e, apresentaram em quase todas as dimensões, um desempenho menor, o que sugere a necessidade de avaliar com maior cautela demandas por recursos de instituições desse território. Originalidade: O estudo evidencia diferenças regionais nos desempenhos dos estudantes de Engenharia com base na TBR.
- Published
- 2022
- Full Text
- View/download PDF
14. The Effect of Pyrolysis Water on Different Levels of a Reactor for Biological Syngas Methanation
- Author
-
Åström, Stina and Åström, Stina
- Abstract
Thermophilic biological syngas methanation has the potential to become an important factor to reduce the usage of fossil fuels and contribute to a resilient energy production in Europe. The technology is built on the complex syntropy of different groups of microbes that together convert syngas (CO, H2, CO2, and some CH4) to CH4 through a variety of pathways. The pathway for CO conversion to CH4 has been less studied than the conversion for H2 and CO2, but several studies have observed that species that perform hydrogenotrophic methanogenesis and the water-gas shift reaction (WGSR) seem to be dominating in biological syngas methanation in thermophilic temperatures. In future commercial plants for biological syngas methanation, the process will perhaps be disturbed by varying amounts of pyrolysis water, a condensate that might enter the reactor with the syngas. Research Institutes of Sweden (RISE) has conducted an experiment where a trickle bed reactor (TBR) has been exposed to pyrolysis water without seeing any apparent effect on the CH4 production. However, after conducting a qPCR analysis, targeting the genera Methanobacterium, on samples from the TBR, it is possible to conclude that the introduction of the contamination indeed had an effect on the methanogenic community since the population decreased at the top of the reactor, where the contamination was decreased. The reason why this was not apparent on the data gathered from the experiment might be because an inoculum which had been thoughtfully chosen with the diversity in mind had been used, and there were plenty of species that could convert the harmful components. This might have protected the lower parts of the reactor while other methanogenic species than Methanobacterium maintained the CH4 production.
- Published
- 2024
15. HCCR breeding blankets optimization by changing neutronic constrictions
- Author
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R. Zadfathollah Seighalani, M. Sedaghatizade, and H. Sadeghi
- Subjects
DEMOnstration tokamak ,HCCR breeding blanket ,Neutronic analysis ,TBR ,Energy deposition ,Nuclear engineering. Atomic power ,TK9001-9401 - Abstract
The neutronic analysis of Helium Cooled Ceramic Reflector (HCCR) breeding blankets has been performed using the 3D Monte Carlo code MCNPX and ENDF nuclear data library. This study aims to reduce 6Li percentage in the breeder zones as much as possible ensuring tritium self-sufficiency. This work is devoted to investigating the effect of 6Li percentage on the HCCR breeding blanket's neutronic parameters, such as neutron flux and spectrum, Tritium Breeding Ratio (TBR), nuclear power density, and energy multiplication factor. In the ceramic breeders at the saturated thickness, increasing the enrichment of 6Li reduces its share in the tritium production. Therefore, ceramic breeders typically use lower enriched Li from 30% to 60%. The investigation of neutronic analysis in the suggested geometry shows that using 60% 6Li in Li2TiO3 can yield acceptable TBR and energy deposition results, which would be economically feasible.
- Published
- 2021
- Full Text
- View/download PDF
16. Neutronic Assessments towards a Novel First Wall Design for a Stellarator Fusion Reactor with Dual Coolant Lithium Lead Breeding Blanket
- Author
-
David Sosa and Iole Palermo
- Subjects
fusion ,DCLL ,breeding blanket ,HELIAS ,TBR ,neutronic ,Technology - Abstract
The Stellarator Power Plant Studies Prospective R&D Work Package in the Eurofusion Programme was settled to bring the stellarator engineering to maturity, so that stellarators and particularly the HELIAS (HELical-axis Advanced Stellarator) configuration could be a possible alternative to tokamaks. However, its complex geometry makes designing a Breeding Blanket (BB) that fully satisfies the requirements for such a HELIAS configuration, which is a difficult task. Taking advantage of the acquired experience in BB design for DEMO tokamak, CIEMAT is leading the development of a Dual Coolant Lithium Lead (DCLL) BB for a HELIAS configuration. To answer the specific HELIAS challenges, new and advanced solutions have been proposed, such as the use of fully detached First Wall (FW) based on liquid metal Capillary Porous Systems (CPS). The proposed solutions have been studied in a simplified 1D model that can help to estimate the relative variations in Tritium Breeding Ratio (TBR) and displacement per atom (dpa) to verify their effectiveness in simplifying the BB integration and improving the machine availability while keeping the main BB nuclear functions (i.e., tritium breeding, heat extraction and shielding). This preliminary study demonstrates that the use of FW CPS would drastically reduce the radiation damage received by the blanket by 29% in some of the selected configurations along with a small decrease of 4.9% in TBR. This could even be improved to just a 3.8% TBR reduction by using a graphite reflector. Such an impact on the TBR is considered affordable, and the results presented, although preliminary in essence, have shown the existence of margins for further development of the FW CPS concept for HELIAS, as they have been not found, at least to date, to be significant showstoppers for the use of this technological solution.
- Published
- 2023
- Full Text
- View/download PDF
17. Neutronics and activation analysis of lithium-based ternary alloys in IFE blankets
- Author
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Jolodosky, Alejandra, Kramer, Kevin, Meier, Wayne, DeMuth, James, Reyes, Susana, and Fratoni, Massimiliano
- Subjects
IFE ,Ternary ,TBR ,EMF ,Enrichment ,Activation ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Mechanical Engineering ,Interdisciplinary Engineering ,Energy - Abstract
An attractive feature of using liquid lithium as the breeder and coolant in fusion blankets is that it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns. The Lawrence Livermore National Laboratory is carrying an effort to develop a lithium-based ternary alloy that maintains the beneficial properties of lithium (e.g. high tritium breeding and solubility) and at the same time reduces overall flammability concerns. This study evaluates the neutronics performance of lithium-based alloys in the blanket of an inertial fusion energy chamber in order to inform such development. 3-D Monte Carlo calculations were performed to evaluate two main neutronics performance parameters for the blanket: tritium breeding ratio (TBR), and the fusion energy multiplication factor (EMF). It was found that elements that exhibit low absorption cross sections and higher q-values such as Pb, Sn, and Sr, perform well with those that have high neutron multiplication such as Pb and Bi. These elements meet TBR constrains ranging from 1.02 to 1.1. However, most alloys do not reach EMFs greater than 1.15. Additionally, it was found that enriching lithium with 6Li significantly increases the TBR and decreases the minimum lithium concentration by more than 60%. The amount of enrichment depends on how much total lithium is in the alloy to begin with. Alloys that performed well in the TBR and EMF calculations were considered for activation analysis. Activation simulations were executed with 50 years of irradiation and 300 years of cooling. It was discovered that bismuth is a poor choice due to achieving the highest decay heat, contact dose rates, and accident doses. In addition, it does not meet the waste disposal ratings (WDR). Some of the activation results for alloys with Sn, Zn, and Ga were in the higher end and should be considered secondary to elements such as Sr and Ba that had overall better results. The results of this study along with other considerations such as thermodynamics, and chemical reactivity will help down select a preferred lithium ternary alloy.
- Published
- 2016
18. Neutronics and activation analysis of lithium-based ternary alloys in IFE blankets
- Author
-
Jolodosky, A, Kramer, K, Meier, W, DeMuth, J, Reyes, S, and Fratoni, M
- Subjects
IFE ,Ternary ,TBR ,EMF ,Enrichment ,Activation ,Energy ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Mechanical Engineering ,Interdisciplinary Engineering - Abstract
An attractive feature of using liquid lithium as the breeder and coolant in fusion blankets is that it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns. The Lawrence Livermore National Laboratory is carrying an effort to develop a lithium-based ternary alloy that maintains the beneficial properties of lithium (e.g. high tritium breeding and solubility) and at the same time reduces overall flammability concerns. This study evaluates the neutronics performance of lithium-based alloys in the blanket of an inertial fusion energy chamber in order to inform such development. 3-D Monte Carlo calculations were performed to evaluate two main neutronics performance parameters for the blanket: tritium breeding ratio (TBR), and the fusion energy multiplication factor (EMF). It was found that elements that exhibit low absorption cross sections and higher q-values such as Pb, Sn, and Sr, perform well with those that have high neutron multiplication such as Pb and Bi. These elements meet TBR constrains ranging from 1.02 to 1.1. However, most alloys do not reach EMFs greater than 1.15. Additionally, it was found that enriching lithium with 6Li significantly increases the TBR and decreases the minimum lithium concentration by more than 60%. The amount of enrichment depends on how much total lithium is in the alloy to begin with. Alloys that performed well in the TBR and EMF calculations were considered for activation analysis. Activation simulations were executed with 50 years of irradiation and 300 years of cooling. It was discovered that bismuth is a poor choice due to achieving the highest decay heat, contact dose rates, and accident doses. In addition, it does not meet the waste disposal ratings (WDR). Some of the activation results for alloys with Sn, Zn, and Ga were in the higher end and should be considered secondary to elements such as Sr and Ba that had overall better results. The results of this study along with other considerations such as thermodynamics, and chemical reactivity will help down select a preferred lithium ternary alloy.
- Published
- 2016
19. Neutronics and activation analysis of lithium-based ternary alloys in IFE blankets
- Author
-
Fratoni, Massimiliano [Univ. of California, Berkeley, CA (United States)]
- Published
- 2016
- Full Text
- View/download PDF
20. Incorporating the Benefits of Geosynthetic into MEPDG
- Author
-
Murad Abu-Farsakh, Mehdi Zadehmohamad, and George Z. Voyiadjis
- Subjects
FEM ,MEPDG ,geosynthetic ,TBR ,MR-eff ,BCR ,Technology - Abstract
One of the most effective ways to increase the longevity of pavement structures is through the integration of geosynthetic reinforcement. Geosynthetics are synthetic materials such as geotextiles, geogrids, or geocomposites that are added to the interface between the subgrade and the base layer of a pavement structure. To evaluate the effect of various parameters on the structural benefits of geosynthetic reinforcement on the pavement structure of low-volume traffic flexible pavements, a finite element (FE) study was performed using the ABAQUS program. These parameters included the geosynthetic type, geosynthetic tensile stiffness, subgrade stiffness, and base thickness. The FE rutting curves for the 100 cycles were calibrated using the mechanistic–empirical (M-E) transfer functions, which were then used to calculate the long-term rutting curves. The traffic benefit ratio (TBR) was initially calculated based on the calibrated rutting curves for each pavement layer. The calculated TBRs were then used as an input in AASHTOWare to compute the base effective resilient modulus (MR-eff) and the factor of base course reduction (BCR). The results showed that adding one layer of geosynthetics enhanced the rutting performance of pavement structures significantly (up to 8.9 in TBR, 322% in MR-eff, and 64% in BCR). Geogrids showed higher benefits than geotextiles due to the interlocking between base aggregates and geogrid aperture. The values of TBR, MR-eff, and BCR increase with the increasing tensile stiffness of the geosynthetics and the rutting target and with the decreasing subgrade stiffness. The results also demonstrated peak values of TBR, MR-eff, and BCR for a base thickness of 25.4 cm.
- Published
- 2023
- Full Text
- View/download PDF
21. Neutronics Perturbation Calculation Method Study of Solid Breeder Tritium Breeding Blanket for TBR Enhancement
- Author
-
Shen Qu, Qixiang Cao, Fengchao Zhao, Xueren Wang, Xuru Duan, and Xiaoyu Wang
- Subjects
neutronics ,HCCB TBB ,TBR ,perturbation calculation ,virtual density theory ,General Works - Abstract
Tritium breeding blanket (TBB) is an essential component in a fusion reactor, which has functions of tritium breeding, energy generation, and neutron shielding. Tritium breeding ratio (TBR) is a key parameter to evaluate whether the TBB could produce enough tritium to achieve the tritium self-sufficiency (TBR >1) for fusion reactor. Current codes or software are hard to meet the requirements of high efficiency, high resolution, and high automation for neutronic optimization of TBB. In this article, the application of the density perturbation calculation on a solid breeder TBB was first performed. Then, the method of the geometry perturbation calculation based on the virtual density theory was studied. Results and comparison analysis indicate that the 1st + 2nd-order neutronic perturbation calculations (including the density perturbation and the geometry perturbation) results are consistent with the transport results under a perturbation of −15% to +15%. It is proven to be valid to use the perturbation calculation for rapid TBR enhancement study of the solid breeder TBB.
- Published
- 2021
- Full Text
- View/download PDF
22. Consequences of Data Loss on Clinical Decision-Making in Continuous Glucose Monitoring: Retrospective Cohort Study.
- Author
-
den Braber N, Braem CIR, Vollenbroek-Hutten MMR, Hermens HJ, Urgert T, Yavuz US, Veltink PH, and Laverman GD
- Abstract
Background: The impact of missing data on individual continuous glucose monitoring (CGM) data is unknown but can influence clinical decision-making for patients., Objective: We aimed to investigate the consequences of data loss on glucose metrics in individual patient recordings from continuous glucose monitors and assess its implications on clinical decision-making., Methods: The CGM data were collected from patients with type 1 and 2 diabetes using the FreeStyle Libre sensor (Abbott Diabetes Care). We selected 7-28 days of 24 hours of continuous data without any missing values from each individual patient. To mimic real-world data loss, missing data ranging from 5% to 50% were introduced into the data set. From this modified data set, clinical metrics including time below range (TBR), TBR level 2 (TBR2), and other common glucose metrics were calculated in the data sets with and that without data loss. Recordings in which glucose metrics deviated relevantly due to data loss, as determined by clinical experts, were defined as expert panel boundary error (ε
EPB ). These errors were expressed as a percentage of the total number of recordings. The errors for the recordings with glucose management indicator <53 mmol/mol were investigated., Results: A total of 84 patients contributed to 798 recordings over 28 days. With 5%-50% data loss for 7-28 days recordings, the εEPB varied from 0 out of 798 (0.0%) to 147 out of 736 (20.0%) for TBR and 0 out of 612 (0.0%) to 22 out of 408 (5.4%) recordings for TBR2. In the case of 14-day recordings, TBR and TBR2 episodes completely disappeared due to 30% data loss in 2 out of 786 (0.3%) and 32 out of 522 (6.1%) of the cases, respectively. However, the initial values of the disappeared TBR and TBR2 were relatively small (<0.1%). In the recordings with glucose management indicator <53 mmol/mol the εEPB was 9.6% for 14 days with 30% data loss., Conclusions: With a maximum of 30% data loss in 14-day CGM recordings, there is minimal impact of missing data on the clinical interpretation of various glucose metrics., Trial Registration: ClinicalTrials.gov NCT05584293; https://clinicaltrials.gov/study/NCT05584293., (©Niala den Braber, Carlijn I R Braem, Miriam M R Vollenbroek-Hutten, Hermie J Hermens, Thomas Urgert, Utku S Yavuz, Peter H Veltink, Gozewijn D Laverman. Originally published in the Interactive Journal of Medical Research (https://www.i-jmr.org/), 31.07.2024.)- Published
- 2024
- Full Text
- View/download PDF
23. APPLICATION OF SUPERMC3.2 TO PRELIMINARY NEUTRONICS ANALYSIS FOR EUROPEAN HCPB DEMO.
- Author
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Margulis, M., Blaise, P., Li, Bin, Wu, Bin, Sun, Guangyao, Hao, Lijuan, Song, Jing, and Fischer, Ulrich
- Subjects
- *
NUCLEAR fusion , *RADIOACTIVITY , *NUCLEAR energy , *NEUTRON transport theory , *NUCLEAR reactions - Abstract
In the D-T fueled tokamak, the neutrons not only carry the approximately 80% energy released in the per fusion reaction, but also are the source of radioactivity in the fusion system. Therefore, high-fidelity neutronics simulation is required to support such reactor design and safety analysis. In the present work, taking European HCPB DEMO (Helium Cooled Pebble Bed demonstration fusion plant) developed by KIT (Karlsruhe Institute of Technology) as an example, the preliminary neutronics analysis covering the assessments of NWL (neutron wall loading), TBR (tritium breeding ratio), nuclear power generation, radiation loads on PFCs (plasma-facing components) and TFCs (toroidal field coils) has been carried out by using SuperMC in the case of both unbiased and biased simulations. The preliminary results indicate that the blanket scheme could satisfy the design requirements in terms of TBR and shielding of inboard blankets. Specially, a speed-up by ~164 times in the calculation for thick shielding region (TFC region) is achieved by using global weight windows generated via GWWG in SuperMC. In addition, compared to MCNP, SuperMC shows advantages in accurate and efficient modeling of complex system, efficient calculation and 3D interactive visualization. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
24. Resting Theta/Beta Ratios Mediate the Relationship Between Motor Competence and Inhibition in Children With Attention Deficit/Hyperactivity Disorder
- Author
-
Chi-Fang Lin, Chung-Ju Huang, Yu-Jung Tsai, Ting-Yu Chueh, Chiao-Ling Hung, Yu-Kai Chang, and Tsung-Min Hung
- Subjects
ADHD ,TBR ,motor ability ,interference ,mediator ,Psychology ,BF1-990 - Abstract
Despite that previous studies have supported relationships between motor ability and inhibitory function, and between resting brain theta/beta power ratios (TBR) and inhibition in children with attention deficit/hyperactivity disorder (ADHD), little research has examined the mechanism within these relationships. The purpose of this study was to investigate whether TBR would mediate the relationship between motor ability and inhibitory function. A total of 71 children with ADHD were recorded resting electroencephalographic (EEG) data during eyes-open. Motor abilities were evaluated by Movement Assessment Battery for Children-2 (MABC-2) and inhibitory ability were assessed by a modified Eriksen’s flanker task. The results of mediation analyses revealed that TBR could completely mediate the relationship between motor competence and response speed (indirect effect = −0.0004, 95% CI [−0.0010, −0.0001]) and accuracy (indirect effect = 0.0003, 95% CI [0.0000, 0.0010]) in the incongruent condition of the flanker task. This study suggests that TBR may be one of the mechanisms between motor ability and inhibition function in children with ADHD.
- Published
- 2021
- Full Text
- View/download PDF
25. Impact of optimized PET imaging conditions on 18F-FDG uptake quantification in patients with apparently normal aortas.
- Author
-
Lawal, Ismaheel O., Mokoala, Kgomotso G., Popoola, Gbenga O., Lengana, Thabo, Ankrah, Alfred O., Stoltz, Anton C., and Sathekge, Mike M.
- Abstract
Background: The cardiovascular committee of the European Association of Nuclear Medicine (EANM) recently published recommendations on imaging conditions to be observed during 18F-FDG PET imaging of vascular inflammation. This study aimed to evaluate the impact of applying these optimized imaging conditions on PET quantification of arterial 18F-FDG uptake.Methods and Results: Fifty-seven patients were prospectively recruited to undergo an early 18F-FDG PET/CT imaging at 60 minutes and repeat delayed imaging at ≥ 120 minutes post tracer injection. Routine oncologic 18F-FDG PET protocol was observed for early imaging, while delayed imaging parameters were optimized for vascular inflammation imaging as recommended by the EANM. Aortic SUVmax of the ascending aorta and SUVmean from the lumen of the superior vena cava (SVC SUVmean) were obtained on early and delayed imaging. Target-to-background ratio (TBR) was obtained for the early and delayed imaging. Aortic SUVmax increased by a mean of 70%, while SVC SUVmean decreased by a mean of 52% between early and delayed imaging (P < 0.001). TBR increased by 122% following delayed imaging. TBR increased, while SVC SUVmean declined across all time-points from 120 to > 180 minutes. Aortic SUVmax significantly increased at imaging time-points between 120 and 180 minutes. No significant improvement in aortic SUVmax was seen at imaging time-points beyond 180 minutes.Conclusions: 18F-FDG PET imaging conditions optimized for vascular inflammation imaging lead to an improved quantification through an increase in the quantified vascular tracer uptake and decrease in blood-pool background activity. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
26. Resting Theta/Beta Ratios Mediate the Relationship Between Motor Competence and Inhibition in Children With Attention Deficit/Hyperactivity Disorder.
- Author
-
Lin, Chi-Fang, Huang, Chung-Ju, Tsai, Yu-Jung, Chueh, Ting-Yu, Hung, Chiao-Ling, Chang, Yu-Kai, and Hung, Tsung-Min
- Subjects
NEURAL inhibition ,PERFORMANCE in children ,MOTOR ability ,HYPERACTIVITY ,ATTENTION-deficit hyperactivity disorder - Abstract
Despite that previous studies have supported relationships between motor ability and inhibitory function, and between resting brain theta/beta power ratios (TBR) and inhibition in children with attention deficit/hyperactivity disorder (ADHD), little research has examined the mechanism within these relationships. The purpose of this study was to investigate whether TBR would mediate the relationship between motor ability and inhibitory function. A total of 71 children with ADHD were recorded resting electroencephalographic (EEG) data during eyes-open. Motor abilities were evaluated by Movement Assessment Battery for Children-2 (MABC-2) and inhibitory ability were assessed by a modified Eriksen's flanker task. The results of mediation analyses revealed that TBR could completely mediate the relationship between motor competence and response speed (indirect effect = −0.0004, 95% CI [−0.0010, −0.0001]) and accuracy (indirect effect = 0.0003, 95% CI [0.0000, 0.0010]) in the incongruent condition of the flanker task. This study suggests that TBR may be one of the mechanisms between motor ability and inhibition function in children with ADHD. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
27. Statistical Analysis of Tritium Breeding Ratio Deviations in the DEMO Due to Nuclear Data Uncertainties.
- Author
-
Park, Jin Hun, Pereslavtsev, Pavel, Konobeev, Alexandre, and Wegmann, Christian
- Subjects
MONTE Carlo method ,STATISTICS ,TRITIUM ,NUCLEAR models ,FUSION reactors - Abstract
For the stable and self-sufficient functioning of the DEMO fusion reactor, one of the most important parameters that must be demonstrated is the Tritium Breeding Ratio (TBR). The reliable assessment of the TBR with safety margins is a matter of fusion reactor viability. The uncertainty of the TBR in the neutronic simulations includes many different aspects such as the uncertainty due to the simplification of the geometry models used, the uncertainty of the reactor layout and the uncertainty introduced due to neutronic calculations. The last one can be reduced by applying high fidelity Monte Carlo simulations for TBR estimations. Nevertheless, these calculations have inherent statistical errors controlled by the number of neutron histories, straightforward for a quantity such as that of TBR underlying errors due to nuclear data uncertainties. In fact, every evaluated nuclear data file involved in the MCNP calculations can be replaced with the set of the random data files representing the particular deviation of the nuclear model parameters, each of them being correct and valid for applications. To account for the uncertainty of the nuclear model parameters introduced in the evaluated data file, a total Monte Carlo (TMC) method can be used to analyze the uncertainty of TBR owing to the nuclear data used for calculations. To this end, two 3D fully heterogeneous geometry models of the helium cooled pebble bed (HCPB) and water cooled lithium lead (WCLL) European DEMOs were utilized for the calculations of the TBR. The TMC calculations were performed, making use of the TENDL-2017 nuclear data library random files with high enough statistics providing a well-resolved Gaussian distribution of the TBR value. The assessment was done for the estimation of the TBR uncertainty due to the nuclear data for entire material compositions and for separate materials: structural, breeder and neutron multipliers. The overall TBR uncertainty for the nuclear data was estimated to be 3~4% for the HCPB and WCLL DEMOs, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
28. QEEG indices in traumatic brain injury - insights from the CAPTAIN RTMS trial.
- Author
-
Olivia VR, Chira D, Chelaru VF, Diana CD, Livia LP, Buruiană AM, and Mureşanu FD
- Subjects
- Humans, Male, Adult, Female, Middle Aged, Amino Acids, Brain Injuries, Traumatic therapy, Brain Injuries, Traumatic physiopathology, Electroencephalography methods, Transcranial Magnetic Stimulation methods
- Abstract
This secondary analysis of the CAPTAIN-RTMS trial data focused on the significance of quantitative electroencephalography (qEEG) indices as indicators of recovery in patients with traumatic brain injury (TBI). By focusing on the delta alpha ratio (DAR), delta theta/alpha beta ratio (DTABR), and theta beta ratio (TBR), this study explored the shifts in brainwave activity as a response to an integrative treatment regimen of repetitive transcranial magnetic stimulation (rTMS) combined with the neurotrophic agent Cerebrolysin. Findings revealed significant increases in DAR and DTABR, suggesting changes in neurophysiological dynamics after treatment. However, variations in TBR were inconclusive in providing clear electrophysiological insights. These results indicate that further research is necessary to describe and understand the underlying mechanisms of brain recovery and to develop refined treatment frameworks for patients with TBI., Competing Interests: The authors declare no conflict of interest., (© 2024 by the authors.)
- Published
- 2024
- Full Text
- View/download PDF
29. Rearrangement operations on unrooted phylogenetic networks
- Author
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Remie Janssen and Jonathan Klawitter
- Subjects
phylogenetic network ,rearrangement ,local search ,tbr ,spr ,nni ,diameter ,np-hard ,Mathematics ,QA1-939 - Abstract
Rearrangement operations transform a phylogenetic tree into another one and hence induce a metric on the space of phylogenetic trees. Popular operations for unrooted phylogenetic trees are NNI (nearest neighbour interchange), SPR (subtree prune and regraft), and TBR (tree bisection and reconnection). Recently, these operations have been extended to unrooted phylogenetic networks, which are generalisations of phylogenetic trees that can model reticulated evolutionary relationships. Here, we study global and local properties of spaces of phylogenetic networks under these three operations. In particular, we prove connectedness and asymptotic bounds on the diameters of spaces of different classes of phylogenetic networks, including tree-based and level-k networks. We also examine the behaviour of shortest TBR-sequence between two phylogenetic networks in a class, and whether the TBR-distance changes if intermediate networks from other classes are allowed: for example, the space of phylogenetic trees is an isometric subgraph of the space of phylogenetic networks under TBR. Lastly, we show that computing the TBR-distance and the PR-distance of two phylogenetic networks is NP-hard.
- Published
- 2019
- Full Text
- View/download PDF
30. Multiple embryo manipulations in PGT-A cycles may result in inferior clinical outcomes.
- Author
-
Vanderhoff, Anna, Lanes, Andrea, Go, Kathryn, Dobson, Lori, Ginsburg, Elizabeth, Patel, Jay, and Srouji, Serene S.
- Subjects
- *
EMBRYOS , *TREATMENT effectiveness , *EMBRYO transfer , *PREGNANCY outcomes , *BIRTH rate - Abstract
• Embryos set for warming, biopsy and re-vitrification (TBR) have a high attrition rate. • Embryos requiring repeat PGT-A have similar ploidy rates to fresh biopsied embryos. • Transfer of TBR embryos may result in impaired pregnancy outcomes. Do embryos that undergo a thaw, biopsy and re-vitrification (TBR) for pre-implantation genetic testing for aneuploidy (PGT-A) have different ploidy and transfer outcomes compared with fresh biopsied embryos? Retrospective cohort study of all embryos that underwent the following procedures: fresh biopsy for PGT-A (fresh biopsy); embryos that were warmed, biopsied for PGT-A and re-vitrified (single biopsy TBR); embryos with a no signal result after initial biopsy that were subsequently warmed, biopsied and re-vitrified (double biopsy TBR). The patients who underwent transfers of those embryos at a single academic institution between March 2013 and December 2021 were also studied. About 30% of embryos planned for TBR underwent attrition. Euploidy rates were similar after biopsy: fresh biopsy (42.7%); single biopsy TBR (47.5%) (adjusted RR: 0.99, 0.88 to 1.12); and double biopsy TBR 50.3% (adjusted RR: 0.99, 0.80 to 1.21). Ongoing pregnancy over 8 weeks was not statistically significant (double biopsy TBR: 6/19 [31.6%] versus fresh biopsy: 650/1062 [61.2%]) (adjusted RR 0.52, 95% CI 0.26 to 1.03). The miscarriage rate increased (double biopsy TBR: 4/19 [21.1%] versus fresh biopsy: 66/1062 [6.2%])(RR 3.39, 95% CI 1.38 to 8.31). Live birth rate was also lower per transfer for the double biopsy TBR group (double biopsy TBR [18.75%] versus fresh biopsy [53.75%]) (RR 0.35, 95% CI 0.12 to 0.98), though not after adjustment (adjusted RR 0.37, 95% CI 0.13 to 1.09). These differences were not seen when single biopsy TBR embryos were transferred. Embryos that undergo TBR have an equivalent euploidy rate to fresh biopsied embryos. Despite that, double biopsy TBR embryos may have impaired transfer outcomes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Study on Multiphysics Coupling and Automatic Neutronic Optimization for Solid Tritium Breeding Blanket of Fusion Reactor
- Author
-
Shen Qu, Qixiang Cao, Xuru Duan, Xueren Wang, and Xiaoyu Wang
- Subjects
multiphysics coupling ,automatic neutronic optimization ,HCCB TBB ,TBR ,Technology - Abstract
A tritium breeding blanket (TBB) is an essential component in a fusion reactor, which has functions of tritium breeding, energy generation and neutron shielding. Tritium breeding ratio (TBR) is a key parameter to evaluate whether the TBB could produce enough tritium to achieve tritium self-sufficiency (TBR > 1) for a fusion reactor. Current codes or software struggle to meet the requirements of high efficiency and high automation for neutronic optimization of the TBB. In this paper, the multiphysics coupling and automatic neutronic optimization method study for a solid breeder TBB is performed, and a corresponding code is developed. A typical module of China fusion engineering test reactor (CFETR) helium cooled ceramic breeder (HCCB) TBB was selected, and a 3D neutronics model of an initial scheme is developed. The automatic neutronic optimization was performed by using the developed code for verification. Results indicate that the TBR could increase from 1.219 to 1.282 (~5.17% improvement), and that the maximum temperature of each type of material in the optimized scheme is below the allowable temperature. It is of great scientific significance and engineering value to explore and study the algorithm for automatic neutronic optimization and the code development of the TBB.
- Published
- 2021
- Full Text
- View/download PDF
32. Microbenchmark Based Performance Evaluation of GPU Rendering
- Author
-
Navik, Ankit P., Zaveri, Mukesh A., Murthy, Sristi Vns, Dawarwadikar, Manoj, Shetty, N. R., editor, Prasad, N.H., editor, and Nalini, N., editor
- Published
- 2015
- Full Text
- View/download PDF
33. Statistical Analysis of Tritium Breeding Ratio Deviations in the DEMO Due to Nuclear Data Uncertainties
- Author
-
Jin Hun Park, Pavel Pereslavtsev, Alexandre Konobeev, and Christian Wegmann
- Subjects
DEMO ,TBR ,MCNP ,total Monte Carlo ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
For the stable and self-sufficient functioning of the DEMO fusion reactor, one of the most important parameters that must be demonstrated is the Tritium Breeding Ratio (TBR). The reliable assessment of the TBR with safety margins is a matter of fusion reactor viability. The uncertainty of the TBR in the neutronic simulations includes many different aspects such as the uncertainty due to the simplification of the geometry models used, the uncertainty of the reactor layout and the uncertainty introduced due to neutronic calculations. The last one can be reduced by applying high fidelity Monte Carlo simulations for TBR estimations. Nevertheless, these calculations have inherent statistical errors controlled by the number of neutron histories, straightforward for a quantity such as that of TBR underlying errors due to nuclear data uncertainties. In fact, every evaluated nuclear data file involved in the MCNP calculations can be replaced with the set of the random data files representing the particular deviation of the nuclear model parameters, each of them being correct and valid for applications. To account for the uncertainty of the nuclear model parameters introduced in the evaluated data file, a total Monte Carlo (TMC) method can be used to analyze the uncertainty of TBR owing to the nuclear data used for calculations. To this end, two 3D fully heterogeneous geometry models of the helium cooled pebble bed (HCPB) and water cooled lithium lead (WCLL) European DEMOs were utilized for the calculations of the TBR. The TMC calculations were performed, making use of the TENDL-2017 nuclear data library random files with high enough statistics providing a well-resolved Gaussian distribution of the TBR value. The assessment was done for the estimation of the TBR uncertainty due to the nuclear data for entire material compositions and for separate materials: structural, breeder and neutron multipliers. The overall TBR uncertainty for the nuclear data was estimated to be 3~4% for the HCPB and WCLL DEMOs, respectively.
- Published
- 2021
- Full Text
- View/download PDF
34. An enhanced, near-term HCPB design as driver blanket for the EU DEMO.
- Author
-
Hernández, Francisco A., Pereslavtsev, Pavel, Zhou, Guangming, Neuberger, Heiko, Rey, Jorg, Kang, Qinlan, Boccaccini, Lorenzo V., Bubelis, Evaldas, Moscato, Ivo, and Dongiovanni, Danilo
- Subjects
- *
BERYLLIUM , *TRITIUM , *FUSION reactor blankets , *IRON & steel plates , *HEAT transfer , *MAGNITUDE (Mathematics) - Abstract
The Helium Cooled Pebble Bed (HCPB) breeding blanket is a candidate as driver blanket for the EU DEMO. The reference design of the HCPB is based on a cooling plate "sandwich" arrangement built in Multi-Module Segments. This architecture significantly improved the tritium breeding performance (TBR = 1.15) and the plant circulating power (≈130 MW) compared to the former ITER-like "beer-box"-like design (TBR<1.10, plant circulating power>200 MW). However, several issues remain with this design, in which (1) the still large power required per He circulator (beyond the state-of-the-art for these components) and (2) the large tritium inventory foreseen in Be have been identified as the most critical. After a basic research for a concept that mitigates these key issues, a fission-like configuration based on a hexagonal matrix of radial fuel-breeder pin assemblies has been found to solve many of the outstanding issues present in the reference design. This design has been developed for the latest EU-DEMO 2017 baseline. It features Be 12 Ti neutron multiplier, which largely reduces the tritium retention, swelling and reactivity issues compared to pure Be. The substitution of the relatively complex CPs by simpler fuel-breeder pins improves the heat transfer capability of the breeder zone (BZ), allowing 20°C higher blanket outlet temperature and drastically reducing an order of magnitude the pressure drop in the BZ. The paper reports the successful set of nuclear, thermo-hydraulic and thermo-mechanical performances, together with some notes about the manufacturing and assembly strategy, the improved RAMI features and emphasizes the reduction of the plant circulating power to a remarkably low figure (˜90 MW), enabling the use state-of-the-art He turbomachinery. Due to some inherent issues connected to the use of Be as neutron multiplier which cannot be simply solved by design, a parallel long research has identified molten lead as a cost-effective, low risk substitute for Be. Taking as basis the HCPB fuel-breeder pin concept, an alternative helium cooled Molten Lead Ceramic Breeder has been derived and some key performance figures are reported. The paper concludes with a discussion on the results and their implications on future development steps. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
35. Three-Phase Reactor Model for Simulation of Methylacetylene and Propadiene Selective Hydrogenation Process.
- Author
-
Ahmadi, A. R., Samimi, F., and Rahimpour, M. R.
- Subjects
ALLENE ,HYDROGENATION ,PROPANE as fuel ,SIMULATION methods & models ,OIL wells ,DIFFERENTIAL evolution - Abstract
In this study, an effort was performed to improve methylacetylene and propadiene (MAPD) hydrogenation process with investigation of operating conditions which significantly influence the reactor performance. For this purpose, the operational parameters including concentration of components in the feedstock as well as hydrogen and diluent (recycle stream) flow rates were optimized via differential evolution (DE) technique to maximize propylene (PR) production, to minimize green oil formation as well as to control PR selectivity. Then a comparison was made between the optimized and non-optimized (design) conditions. The results indicate that in optimal conditions, PR production rate increases 5.3 ton/day, while the green oil formation as well as propane (PN) production, as unwanted byproducts are reduced to 0.05 and 0.85 ton/day in comparison with the design conditions. Reduction of undesirable byproducts and enhancement of propylene production rate, demonstrate superiority of the optimized conditions to design conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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36. Novel method using Hjorth mobility analysis for diagnosing attention-deficit hyperactivity disorder in girls.
- Author
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Chow, Julie Chi, Ouyang, Chen-Sen, Chiang, Ching-Tai, Yang, Rei-Cheng, Wu, Rong-Ching, Wu, Hui-Chuan, and Lin, Lung-Chang
- Subjects
- *
THETA rhythm , *ATTENTION-deficit hyperactivity disorder - Abstract
Abstract Background Attention-deficit hyperactivity disorder (ADHD) is a common childhood neuropsychiatric disorder. Diagnosis of ADHD is based on core symptoms or checklists; however, practitioner subjectivity inevitably results in instances of over- or under-diagnosis. Although an elevated theta/beta ratio (TBR) of the electroencephalography (EEG) band has been approved by the Food and Drug Administration as a factor that may be used in diagnosis of ADHD, several studies have reported no significant differences between the TBR of patients with ADHD and controls. Purpose In this study, a method was developed based on Hjorth Mobility (M) analysis of EEG to compare patients with ADHD and controls. Methods Differences in the presentations of ADHD between boys and girls are well established; therefore, separate investigations are required. The present study enrolled 30 girls with ADHD and 30 age-matched controls. Results The results revealed that the control group had significantly higher Hjorth M values in most brain areas in EEG readings compared with the values for the ADHD group. Compared with TBR, our method revealed a greater number of more significant differences between the girls in the ADHD group and the controls. Moreover, our method can produce the higher average sensitivity (0.796), average specificity (0.796), average accuracy (0.792), and average area under the curve of receiver operating characteristic curve (AUC) value (0.885). Therefore, compared with TBR, Hjorth M possessed the better potential for differentiating between girls with ADHD and controls. Conclusion The proposed method was more accurate than the TBR in diagnosing ADHD. Therefore, Hjorth M may be a promising tool for differentiating between children with ADHD and controls. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
37. Neutronic assessments towards a comprehensive design of DEMO with DCLL breeding blanket.
- Author
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Palermo, Iole, Fernández-Berceruelo, Iván, Rapisarda, David, and Ibarra, Angel
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- *
TRITIUM , *FUSION reactor divertors , *HEATING , *NEUTRAL beams , *HEAT flux - Abstract
Highlights • TBR and nuclear heating have been studied for the last version of DCLL BB for DEMO. • Upgrades of this baseline are analyzed under neutronic point of view. • The impact on nuclear performances of different FW designs is addressed. • Two FCI designs with different strategies for their neutronic simulation also affect the TBR result. • The divertor compositions is also demonstrated to have impact on TBR. • NBI integration consequences on TBR and NH are evaluated. Abstract On the way towards a comprehensive design of DEMO, step by step all the systems and components must be introduced as their definition or refinement progresses, in order to demonstrate the viability of a design on larger scale, i.e. leaving fewer margins to undetermined questions. Among the EUROfusion Programme, new aspects have been recently fixed or further developed as the Divertor, the First Wall (FW) and the Flow Channel Inserts (FCI) designs. Furthermore, the integration of Heating and Current Drive (H&CD) systems, as the Neutral Beam Injector (NBI), has started. The introduction or modification of these systems and components could seriously jeopardize the nuclear behaviour of an initially validated Breeding Blanket (BB) DEMO concept, since many neutronics criteria - among others - could be no more fulfilled. Since the design of DEMO is a continuous upgrade under iterative process, as the advances push on, most of the studies have to be repeated to demonstrate that criteria are still respected in a fully integrated design. The consequences of these upgrades over the neutronic responses are addressed in this paper. Among others, the influence on Tritium Breeding Ratio (TBR) of a new design of detached FW protecting BB from high heat fluxes is investigated. The impact of different typologies of FCIs is assessed also according to the degree of detail in the neutronic description. The divertor composition also reveals to have strong impact on responses apparently not related with its design, as the tritium production in the BB. Besides, the integration of NBI minimizing its invasiveness in the BB is verified by neutronic analyses concerning the main BB functions: fuel breeding and heat generation. Accordingly, TBR and Nuclear Heating (NH) are assessed. The study is performed for a Dual Coolant Lead Lithium (DCLL) BB DEMO although can be extrapolated to other BB concepts. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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38. First principles review of options for tritium breeder and neutron multiplier materials for breeding blankets in fusion reactors.
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Hernández, F.A. and Pereslavtsev, P.
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- *
FUSION reactors , *EUTECTIC reactions , *TRITIUM , *NEUTRONS , *MELTING points - Abstract
Abstract The current breeding blankets proposed in the different conceptual fusion power plants are based mainly on the use of Li 4 SiO 4 and/or Li 2 TiO 3 as tritium breeder and Be/Be 12 Ti as neutron multiplier or an eutectic Li 17 Pb 83 for as a hybrid tritium and neutron multiplier. While these materials offer some tritium breeding capabilities, some recent studies show that the tritium self-sufficiency may not be ensured with these materials due to the strong reduction of blanket coverage after the integration of other in-vessel reactor systems (heating and current drive, limiters, large or double-null divertor systems, etc.). Also, some materials like Be raises several key feasibility concerns. The goal of this paper is to perform an update of the screening for tritium breeder and neutron multiplier materials and to assess the tritium breeding performance of the selected compounds in order to reveal new options. As for the neutron multiplier materials, a new subdivision between solid and liquid multipliers is proposed. For the selected compounds, detailed 3D heterogeneous neutronic analyses have been performed with MCNP5-1.60 assuming the architecture of the current EU DEMO Helium Cooled Pebble Bed (HCPB) as a benchmark breeding blanket. From the point of view of ceramic breeders, Li 8 ZrO 6 has been found to outperform Li 4 SiO 4 by more than 4% in terms of tritium breeding, having 6% higher melting point. From the point of view of solid neutron multipliers, Be 12 Cr, Be 12 V, Be 13 Zr and Be 13 Y show a similar performance as Be 12 Ti, while LaPb 3 , Zr 5 Pb 4 and YPb 2 offer a solution for a Be-free blanket. As for liquid multipliers, Pb in combination with a ceramic breeder shows a very promising option. Moreover, Pb compounds like Pb 90 Mn 10 and Pb 95 Ba 5 offer similar performance as Pb with a lower melting point (290 °C). Due to the significant advantages of molten Pb as neutron multiplier, future work will be conducted to define a design of a helium cooled Molten Lead Ceramic Breeder blanket, as simple, cost effective blanket concept. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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- View/download PDF
39. APPLICATION OF SUPERMC3.2 TO PRELIMINARY NEUTRONICS ANALYSIS FOR EUROPEAN HCPB DEMO
- Author
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Li Bin, Wu Bin, Sun Guangyao, Hao Lijuan, Song Jing, and Fischer Ulrich
- Subjects
supermc ,hcpb demo ,neutronics ,tbr ,gwwg ,Physics ,QC1-999 - Abstract
In the D-T fueled tokamak, the neutrons not only carry the approximately 80% energy released in the per fusion reaction, but also are the source of radioactivity in the fusion system. Therefore, high-fidelity neutronics simulation is required to support such reactor design and safety analysis. In the present work, taking European HCPB DEMO (Helium Cooled Pebble Bed demonstration fusion plant) developed by KIT (Karlsruhe Institute of Technology) as an example, the preliminary neutronics analysis covering the assessments of NWL (neutron wall loading), TBR (tritium breeding ratio), nuclear power generation, radiation loads on PFCs (plasma-facing components) and TFCs (toroidal field coils) has been carried out by using SuperMC in the case of both unbiased and biased simulations. The preliminary results indicate that the blanket scheme could satisfy the design requirements in terms of TBR and shielding of inboard blankets. Specially, a speed-up by ~164 times in the calculation for thick shielding region (TFC region) is achieved by using global weight windows generated via GWWG in SuperMC. In addition, compared to MCNP, SuperMC shows advantages in accurate and efficient modeling of complex system, efficient calculation and 3D interactive visualization.
- Published
- 2021
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40. Clinical efficacy of neurofeedback protocols in treatment of Attention Deficit/Hyperactivity Disorder (ADHD): A systematic review.
- Author
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Saif, Mohammed Gamil Mohammed and Sushkova, Lyudmila
- Subjects
- *
CENTRAL nervous system stimulants , *BIOFEEDBACK training , *MEDICAL protocols , *ATTENTION-deficit hyperactivity disorder , *HYPERACTIVITY - Abstract
• Neurofeedback training is a promising alternative treatment for ADHD. • TBR, SCPs, and SMR neurofeedback protocols are most commonly used for treating ADHD. • QEEG-informed selection of neurofeedback protocol improves the efficacy of neurofeedback. • The efficacy of neurofeedback applied for treating ADHD is still controversial issue. Attention Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder of childhood and its effects mostly continue to adulthood. Neurofeedback training has shown promising results in the treatment of ADHD. However, there is no yet consensus as to the efficacy of neurofeedback in comparison to stimulant medication. Despite a large number of meta-analyses and comparative reviews on the effects of neurofeedback in the treatment of ADHD, there is a lack of comparative reviews on the efficacy of neurofeedback protocols. This review aims at examining the effect of different training protocols on the efficacy of neurofeedback in the treatment of ADHD across specific research studies published between 2017 and 2022. Altogether, a total of 916 records were identified and 18 articles met the inclusion criteria. Findings show that the efficacy of different neurofeedback protocols has been comparable to the efficacy of stimulant medications. Nevertheless, there is still room for more clinical trials on neurofeedback protocols for ADHD since some studies suggest not using neurofeedback as a stand-alone treatment for ADHD. To my knowledge, this systematic review is the first to review neurofeedback protocols for ADHD. This study provides significant implications and directions for researchers to conduct research, on alternatives to stimulant medications for ADHD, in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
41. Impact of optimized PET imaging conditions on 18F-FDG uptake quantification in patients with apparently normal aortas
- Author
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Lawal, Ismaheel O., Mokoala, Kgomotso G., Popoola, Gbenga O., Lengana, Thabo, Ankrah, Alfred O., Stoltz, Anton C., and Sathekge, Mike M.
- Published
- 2021
- Full Text
- View/download PDF
42. On the Complexity of Parameterized Local Search for the Maximum Parsimony Problem
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Komusiewicz, Christian, Linz, Simone, Morawietz, Nils, and Schestag, Jannik
- Subjects
phylogenetic trees ,NNI ,Theory of computation → Parameterized complexity and exact algorithms ,Applied computing → Molecular evolution ,Applied computing → Computational genomics ,tree distances ,parameterized complexity ,TBR - Abstract
Maximum Parsimony is the problem of computing a most parsimonious phylogenetic tree for a taxa set X from character data for X. A common strategy to attack this notoriously hard problem is to perform a local search over the phylogenetic tree space. Here, one is given a phylogenetic tree T and wants to find a more parsimonious tree in the neighborhood of T. We study the complexity of this problem when the neighborhood contains all trees within distance k for several classic distance functions. For the nearest neighbor interchange (NNI), subtree prune and regraft (SPR), tree bisection and reconnection (TBR), and edge contraction and refinement (ECR) distances, we show that, under the exponential time hypothesis, there are no algorithms with running time |I|^o(k) where |I| is the total input size. Hence, brute-force algorithms with running time |X|^𝒪(k) ⋅ |I| are essentially optimal. In contrast to the above distances, we observe that for the sECR-distance, where the contracted edges are constrained to form a subtree, a better solution within distance k can be found in k^𝒪(k) ⋅ |I|^𝒪(1) time., LIPIcs, Vol. 259, 34th Annual Symposium on Combinatorial Pattern Matching (CPM 2023), pages 18:1-18:18
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- 2023
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43. Neutronic analyses in support of the WCLL DEMO design development.
- Author
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Moro, Fabio, Del Nevo, Alessandro, Flammini, Davide, Martelli, Emanuela, Mozzillo, Rocco, Noce, Simone, and Villari, Rosaria
- Subjects
- *
NUCLEAR power plants , *FUSION reactor blankets , *NEUTRON transport theory , *TRITIUM , *COMPUTER simulation - Abstract
Highlights • A Multi-Module-Segment (MMS) DEMO model integrating the WCLL BB has been developed. • The MMS WCLL DEMO shielding capability and TBR have been assessed. • Results highlight that the MMS WCLL DEMO satisfies the design targets (TBR, shielding). • The MCNP model of a Single-Module-Segment (SMS) WCLL DEMO has been developed. • The TBR assessment shows that the SMS WCLL DEMO satisfies the design requirement. Abstract In the frame of the EUROfusion Consortium programme, the Water Cooled Lithium Lead (WCLL) option has been chosen as a candidate for the breeding blanket (BB) of the European fusion power demonstration plant (DEMO) conceptual design. Neutronic analyses play a fundamental role in the development of the WCLL blanket, providing guidelines for its design based on the evaluation of the nuclear performances. A detailed three-dimensional MCNP model of the latest WCLL layout has been generated and integrated in a DEMO MCNP generic model suitably designed for neutronic analyses. Three-dimensional neutron and gamma transport simulations have been performed using the MCNP5v1.6 Monte Carlo code and JEFF 3.2 nuclear data libraries, in order to assess the WCLL-DEMO tritium self-sufficiency and the shielding capabilities of the breeding blanket/manifold system to protect the vacuum vessel and toroidal field coils. Furthermore, radial profiles of the neutron flux, nuclear heating, neutron damage and he-production have been assessed in the inboard and outboard equatorial planes. The outcome of the present study highlights the potential and suitability of the WCLL breeding blanket for the application to DEMO, both in terms of tritium production and shielding performances. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
44. Tritium breeding performance of a DEMO based on the Double Null divertor configuration.
- Author
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Pereslavtsev, Pavel, Fischer, Ulrich, Lu, Lei, Bachmann, Christian, Federici, Gianfranco, and Maviglia, Francesco
- Subjects
- *
TRITIUM , *LEAD , *FUSION reactor divertors , *LITHIUM , *FUSION reactor blankets , *MONTE Carlo method - Abstract
Abstract Different design modifications of a Double Null (DN) DEMO were analysed by means of 3D Monte Carlo calculations using the MCNP code to assess the effect of a DN divertor configuration and various in-vessel components (IVC) on the tritium breeding performance. A simplified DN DEMO model was set up to this end. A Tritium Breeding Ratio (TBR) of 1.14 was obtained with this model for the HCPB breeder blanket concept without taking into account any auxiliary equipment such as limiters or port plugs. The inclusion of such design modifications results in a significant reduction of the TBR for different breeder blanket concepts. To compensate the loss of breeder space in the reactor either the integration of breeder materials in the divertor body or the enlargement of the available breeder zone could be considered. Both of these options can provide an increase of the TBR and ensure a sufficient margin for a DN DEMO with a HCPB breeder blanket. Meeting the TBR requirement with a Pb-Li based breeder blanket concept would be more challenging and requires significant changes to the overall IVC configuration. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
45. Kinetic parameter estimation and simulation of trickle-bed reactor for hydrodesulfurization of whole fraction low-temperature coal tar.
- Author
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Feng, Xian, Li, Dong, Chen, Junghui, Niu, Menglong, Liu, Xu, Chan, Lester Lik Teck, and Li, Wenhong
- Subjects
- *
TRICKLE bed reactors , *PARAMETER estimation , *DESULFURIZATION , *COAL tar , *CHEMICAL kinetics - Abstract
With whole-fraction low temperature coal tar (LTCT) as raw material, which boiling point range is 209–514 °C. This paper conducts hydrotreatment (HDT) test for 1176 h on trickle-bed reactor (TBR) with commercial NiMo/Al 2 O 3 -SiO 2 catalyst. The reaction conditions are as follows: reaction temperature 613–653 K, reaction pressure 10–14 MPa, liquid hourly space velocity (LHSV) 0.2–0.4 h −1 , and hydrogen-to-oil volume ratio 1000:1. Considering the short life of coal tar HDT catalyst, a kinetic model of whole-fraction LTCT hydrodesulfurization (HDS) including running time ( t 1 ) and catalyst half-life ( t c ) was established. The kinetic parameter estimation was conducted according to the experimental data, and the results are as follows: activation energy 94965 J/mol, reaction order 1.5, and the relative error of the model is less than 5%. Based on the premise of steady state operation, the HDS reaction happened in the three-phase trickle-bed reactor was simulated by combining the mass transfer, reaction kinetics model and physical property data of LTCT. The results show that the experimental and simulated values of sulphur content at the exit of the reactor are within the error range of 5%. By simulating the whole-fraction LTCT HDS reactor, the pattern of changes in the concentrations of hydrogen sulfide, hydrogen and sulfur in gas, liquid and solid phases according to the length of the reactor were obtained. Based on this, this paper discusses on the impacts of each process parameter and hydrogen sulfide partial pressure on LTCT HDS, and works out the reaction characteristics of whole-fraction LTCT HDS different from crude oil fraction. Finally, this paper analyzes the influence of different process conditions on internal gradients of catalyst, and concludes the influence of each parameter on effectiveness factor of particle. The increase of temperature, decrease of pressure or increase of LHSV can all cause the decrease of effectiveness factor, wherein the temperature has the most significant effect on the effectiveness factor, followed by LHSV, and pressure has the weakest effect. These findings contribute to a more in-depth understanding of the features and rules of LTCT HDS, and can also give us some guidance for industrial reactor simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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- View/download PDF
46. Sensitivity study on tritium transport in water cooled solid blanket of China Fusion Engineering Test Reactor.
- Author
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Li, Yuanjie, Mai, ChaoWei, Yu, Xudong, Xiang, Yang, Zhao, Pinghui, and Yang, Wanli
- Subjects
- *
TRITIUM , *WATER cooled reactors , *LITHIUM , *HYDROGEN , *TUNGSTEN - Abstract
The Water Cooled Solid Blanket (WCSB) is selected as a basic choice of the CFETR blanket design, where the tritium would be bred by lithium and extracted subsequently in the tritium cycling loop. However, there always some inevitable losses exist during the tritium cycle due to the complexity of the system, which is considered as a big concern of the tritium self-consistency. In order to realize the tritium self-consistency of CFETR, a mathematical-physical model is developed to analyze the tritium transport in the WCSB. In the present work, the sensitivity study of some key parameters on tritium losses and inventories were conducted. It was found that the tritium transport in the WCSB is influenced by the (a) thickness of the tungsten which covers the first wall, (b) the concentration of the hydrogen in the coolant water and (c) the content of the water in the purge gas, etc. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
47. Evaluation of optical imaging agents in a fluorescence-guided surgical model of head and neck cancer.
- Author
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Prince, Andrew C., Moore, Lindsay S., Tipirneni, Kiranya E., Ramesh, Tushar, Limdi, Mihir A., Bevans, Stephanie L., Walsh, Erika M., Greene, Benjamin, Rosenthal, Eben L., and Warram, Jason M.
- Subjects
- *
NEAR infrared radiation , *METASTASIS , *DIAGNOSTIC imaging , *BIOLUMINESCENCE , *CANCER treatment - Abstract
Background: Tumor proliferation often occurs from pathologic receptor upregulation. These receptors provide unique targets for near-infrared (NIR) probes that have fluorescence-guided surgery (FGS) applications. We demonstrate the use of three smart-targeted probes in a model of head and neck squamous cell carcinoma. Methods: A dose escalation study was performed using IntegriSense750, ProSense750EX, and ProSense750FAST in mice (n = 5) bearing luciferase-positive SCC-1 flank xenograft tumors. Whole body fluorescence imaging was performed serially after intravenous injection using commercially available open-field (LUNA, Novadaq, Canada) and closed-field NIR systems (Pearl, LI-COR, Lincoln, NE). An ex vivo, whole-body biodistribution was conducted. Lastly, FGS was performed with IntegriSense750 to demonstrate orthotopic and metastatic disease localization. Results: Disease fluorescence delineation was assessed by tumor-to-background fluorescence ratios (TBR). Peak TBR values were 3.3 for 1 nmol ProSense750EX, 5.5 for 6 nmol ProSense750FAST, and 10.8 for 4 nmol IntegriSense750 at 5.5, 3, and 4 d post administration, respectively. Agent utility is unique: ProSense750FAST provides sufficient contrast quickly (TBR: 1.5, 3 h) while IntegriSense750 produces strong (TBR: 10.8) contrast with extended administration-to-resection time (96 h). IntegriSense750 correctly identified all diseased nodes in situ during exploratory surgeries. Ex vivo, whole-body biodistribution was assessed by tumor-to-tissue fluorescence ratios (TTR). Agents provided sufficient fluorescence contrast to discriminate disease from background, TTR>1. IntegriSense750 was most robust in neural tissue (TTR: 64) while ProSense750EX was superior localizing disease against lung tissue (TBR: 13). Conclusion: All three agents appear effective for FGS. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
48. Divertor options impact on DEMO nuclear performances.
- Author
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Palermo, Iole, Villari, Rosaria, and Ibarra, Angel
- Subjects
- *
FUSION reactor divertors , *FUSION reactors , *NUCLEAR reactor design & construction , *TRITIUM , *NEUTRON flux , *FUSION reactor materials - Abstract
The present paper addresses the impact of the divertor option on the nuclear performances of the Demonstration fusion reactor (DEMO). As the effect of the number and size of the divertor has been already evaluated, in this work the focus has been posed on the composition in terms of amount of cooling inside the divertor cassette. Transport responses, as the Tritium breeding ratio (TBR), neutron and gamma fluxes and spectra inside the plasma chamber, as well as activation responses such as shutdown dose rate, decay gamma fluxes and heating have been evaluated for two different blanket concepts of the future European DEMO reactor: DCLL and WCLL. Three different divertor compositions have been tested demonstrating the importance of this component not only locally but in the global radiation field. The transport analysis has been performed with the Monte Carlo code MCNP5 and the JEFF3.1.1 and JEFF3.2 data libraries. The activation responses calculated using Advanced D1S method have been recently assessed and summarized in the present paper. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
49. HCCR breeding blankets optimization by changing neutronic constrictions
- Author
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M. Sedaghatizade, R. Zadfathollah Seighalani, and Hamid Mirmohammad Sadeghi
- Subjects
Materials science ,020209 energy ,Nuclear engineering ,02 engineering and technology ,Blanket ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Breeder (animal) ,Tritium breeding ratio ,Neutronic analysis ,Neutron flux ,0202 electrical engineering, electronic engineering, information engineering ,Ceramic ,TBR ,business.industry ,TK9001-9401 ,HCCR breeding blanket ,Nuclear data ,Nuclear power ,DEMOnstration tokamak ,Nuclear Energy and Engineering ,visual_art ,visual_art.visual_art_medium ,Energy deposition ,Nuclear engineering. Atomic power ,Tritium ,business - Abstract
The neutronic analysis of Helium Cooled Ceramic Reflector (HCCR) breeding blankets has been performed using the 3D Monte Carlo code MCNPX and ENDF nuclear data library. This study aims to reduce 6Li percentage in the breeder zones as much as possible ensuring tritium self-sufficiency. This work is devoted to investigating the effect of 6Li percentage on the HCCR breeding blanket’s neutronic parameters, such as neutron flux and spectrum, Tritium Breeding Ratio (TBR), nuclear power density, and energy multiplication factor. In the ceramic breeders at the saturated thickness, increasing the enrichment of 6Li reduces its share in the tritium production. Therefore, ceramic breeders typically use lower enriched Li from 30% to 60%. The investigation of neutronic analysis in the suggested geometry shows that using 60% 6Li in Li2TiO3 can yield acceptable TBR and energy deposition results, which would be economically feasible.
- Published
- 2021
50. Thermal Neutron Measurement Capability of a Single Crystal CVD Diamond Detector near the Reactor Core Region of UTR-KINKI
- Author
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KOBAYASHI, Makoto I., YOSHIHASHI, Sachiko, YAMANISHI, Hirokuni, SANGAROON, Siriyaporn, OGAWA, Kunihiro, ISOBE, Mitsutaka, URITANI, Akira, OSAKABE, Masaki, KOBAYASHI, Makoto I., YOSHIHASHI, Sachiko, YAMANISHI, Hirokuni, SANGAROON, Siriyaporn, OGAWA, Kunihiro, ISOBE, Mitsutaka, URITANI, Akira, and OSAKABE, Masaki
- Abstract
Thermal neutron flux evaluation using a single crystal diamond detector (SDD) was carried out in the core region of the UTR-KINKI reactor where a mixed radiation field by thermal and fast neutrons and gamma-ray exists. The pulse shape discrimination method to extract pulses with a rectangular shape as well as a wide pulse-width was established to exclude pulses induced by gamma-rays. The SDD, using a 6LiF thermal neutron converter, is able to detect pulse events caused not only by fast neutrons but also by thermal neutrons through energy depositions into the diamond by energetic alpha and triton particles induced by thermal neutrons. Additionally, the SDD without the thermal neutron converter was used for the measurement of the energy deposition events only by fast neutrons. A comparison of the pulse counts of the SDD with or without the thermal neutron convertor deduced the energy deposition spectra by thermal neutrons. The thermal neutron flux in the core region of the UTR-KINKI reactor was evaluated to be 7.6 × 106 n cm−2 s−1 W−1 up to a reactor power of 1 W., source:https://doi.org/10.1585/pfr.17.2405045, identifier:0000-0003-0920-2154
- Published
- 2022
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