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| 2. |
- Boehle, Frederik, et al.
(författare)
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Compression of CEP-stable multi-mJ laser pulses down to 4 fs in long hollow fibers
- 2014
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Ingår i: Laser Physics Letters. - : IOP Publishing. - 1612-2011 .- 1612-202X. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- Carrier-envelope phase stable 4 fs near-IR pulses with 3 mJ energy were generated by spectral broadening of circularly polarized 8 mJ pulses in a differentially pumped 2 m long composite stretched flexible hollow fiber. The pulses were characterized using both second-harmonic generation frequency-resolved optical gating (SHG-FROG) and SHG d-scan methods.
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| 3. |
- Dévai, Gergely, et al.
(författare)
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Efficient Code Generation from the High-level Domain-specific Language Feldspar for DSPs
- 2010
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Ingår i: ODES-8: 8th Workshop on Optimizations for DSP and Embedded Systems, workshop associated with IEEE/ACM International Symposium on Code Generation and Optimization (CGO).
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Konferensbidrag (refereegranskat)abstract
- Software for digital signal processors (DSPs) is traditionally highly hardware-dependent and hence porting it to new processors usually requires significant design effort. In this paper we present Feldspar (Functional Embedded Language for DSP and Parallelism), an embedded, high-level, domain-specific language for DSP algorithm design and the compilation techniques we developed for generating C code from specifications written in Feldspar. While Feldspar allows description of algorithms on specification level, we show that with the right set of abstractions and transformations this high level, functional specification can be transformed into C code that is comparable or better than reference, hand-crafted C language implementations. The Feldspar compiler is highly modular and plugin-based, hence future hardware-specific plugins will enable automatic generation of efficient, hardware-specific code. This approach enables the encapsulation of knowledge of hardware completely in the compiler and thus allows description of algorithms in completely hardware-independent, portable manner.
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| 4. |
- Hazay, Máté, et al.
(författare)
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Engineering optimization of decompressive craniectomy based on finite element simulations
- 2020
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Ingår i: Acta of bioengineering and biomechanics. - : Wroclaw University of Technology. - 1509-409X .- 1509-409X. ; 22:4, s. 109-122
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The optimal execution of decompressive craniectomy in terms of the size and location of the skull opening is not straightforward. Our main goals are twofold: (1) constructing a design optimization method which can be applied to determine optimal skull opening for individual patient-specific cases and (2) performing a large-scale parametric optimization study to give some guidance in general about the optimal skull opening in case of oedematous brain tissue.Methods: A large number of virtual experiments performed by finite element simulations were applied to determine tendencies of tissue behaviour during surgery. The multiobjective optimization is performed by Goal Programming and Physical Programming methods.Results: Our results show that the postoperative pressure has an approximately linear dependence on the preoperative pressure and the skull opening area, while the damaged brain volume could have a more complex nonlinear dependence on the input data. Based on the averaged results of the parametric optimization study, the optimal skull opening has been determined in the function of the preoperative pressure and the relative importance of the pressure reduction. These results show that the optimal size of the unilateral skull opening is usually between 130-180 cm² and these openings are more beneficial than the currently analysed bifrontal openings.Conclusions: The optimal skull opening is patient-specific and depends on several input data. The presented methodology can be applied to optimize surgery based on these input parameters for different injury types. Based on the results of large-scale parametric study generally applicable approximate results have been provided.
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| 5. |
- Nagy, Lajos, 1991, et al.
(författare)
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Computational Investigation and Experimental Verification of Multiplicity Counting from the Continuous Signals of Fission Chambers
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In a series of previous publications, we suggested an alternative method to the pulse-counting based multiplicity counting technique for the characterisation of special nuclear materialscollision number expansion. The new method uses the continuous signals of fission chambers, and the multiplicity rates, i.e. the singles, doubles and triples rates are extracted from the auto- and cross-covariances of one or more fission chambers. Until recently only the theory of the method was elaborated. The purpose of the work described in this report was to verify the method and investigate its performance and applicability through detailed simulations as well as with a dedicated experiment. Numerical simulations of the method were performed by a code specially developed for this study, and pilot measurements were performed at the critical assembly KUCA of the Institute for Integrated Radiation and Nuclear Science, Kyoto University (KURNS). This report gives an account of both the work performed and the results of the study.
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| 6. |
- Nagy, Lajos, 1991, et al.
(författare)
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Measurements and simulations to investigate the feasibility of neutron multiplicity counting in the current mode of fission chambers
- 2020
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 225
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Konferensbidrag (refereegranskat)abstract
- In two earlier papers [1], [2] we investigated the possibility of extracting traditional multiplicity count rates from the cumulants of fission chamber signals in current mode. It was shown that if all neutrons emitted from the sample simultaneously are also detected simultaneously, the multiplicity rates can be retrieved from the first three cumulants of the currents of up to three detectors, but the method breaks down if the detections of neutrons of common origin take place with a time delay spread wider than the pulse shape. To remedy these shortcomings, in this work we extended the theory to two- and three-point distributions (correlations). It was found thatthe integrals of suitably chosen two- and three-point moments with respect to the time differences become independent of the probability density of the time delays of detections. With this procedure, the multiplicity rates can be retrieved from the detector currents for arbitrary time delay distributions. To demonstrate the practical applicability of the proposed method, a measurement setup was designed and built. The statistics (shape and amplitude distribution) of the detector pulse were investigated as important parameters of the theoretical model. Simulations were performed to estimate the expected value of the multiplicity rates in the built setup. Measurements were performed and two types of moments (the mean and the covariance function) of the recorded detector signals were calculated. Values of singles rates were successfully recovered.
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| 7. |
- Pazsit, Imre, 1948, et al.
(författare)
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Ringhals Diagnostics and Monitoring, Annual Research Report 2019-2020
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report gives an account of the work performed by the Division of Subatomic, High Energy and Plasma Physics (formerly, Division of Nuclear Engineering), Chalmers, in the frame of a research collaboration with Ringhals, Vattenfall AB, contract No. 686103-003. The contract constitutes a 1-year co-operative research work concerning diagnostics and monitoring of the BWR and PWR units. The work in the contract has been performed between July 1st 2019, and June 30th, 2020. Originally, we planned to work with five items as follows: 1. Continued investigation of possible baffle jetting in R3 with noise analysis of in-core and ex-core detector signals; 2. Further analysis of the vibrations of thimble tubes with axially dependent in-core measurements in various radial positions; 3. Evaluation of new ex-core measurements for beam mode and tilting mode vibrations in R3; 4. Experimental work and simulations in support of the use of fission chambers in the current mode for reactor diagnostics, as an alternative of pulse counting methods; 5. Development of a new method to determine the axial velocity profile of the void in the core of a BWR by using four permanent in-core LPRMs and a TIP detector. Due to changed circumstances, mostly related to the Covid-19 pandemics, some changes were made in the project. Item #1 was reduced, whereas the work planned in item #2 was postponed to the next Stage. The work was performed by Imre Pázsit (project co-ordinator), Luis Alejandro Torres and Cristina Montalvo (research collaborators from UPM, Madrid), Lajos Nagy (double degree PhD student jointly with BME Budapest), Gergely Klujber and Máté Szieberth (research collaborators from BME), Tsuyoshi Misawa and Yasunori Kitamura (research collaborators from KURNS, Kyoto, Japan) and Henrik Nylén, the contact person at Ringhals.
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| 8. |
- Pazsit, Imre, 1948, et al.
(författare)
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Ringhals Diagnostics and Monitoring, Annual Research Report 2020-2021
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report gives an account of the work performed by the Division of Subatomic, High Energy and Plasma Physics (formerly, Division of Nuclear Engineering), Chalmers, in the frame of a research collaboration with Ringhals, Vattenfall AB, contract No. 4501737229-003. The contract constitutes a one-year co-operative research work concerning diagnostics and monitoring of the BWR and PWR units. The work in the contract has been performed between 1 July 2020 and 30 June 2021.
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| 9. |
- Szabó, Viktor, et al.
(författare)
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Minimálisan invazív és O-arm asszisztált en bloc gerincdaganat-reszekciók : [Minimally invasive and o-arm assisted en bloc spinal tumor resections]
- 2022
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Ingår i: Ideggyogyaszati Szemle. - : Literatura Medica Kiado. - 0019-1442 .- 2498-6208. ; 75:1-2, s. 65-72
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: The en bloc resection of spinal tumors is required in primary spine tumors and in selected cases of secondary spine tumors, where the primary disease is under control and long survival time is expected. Three cases are presented, applying O-arm assisted navigation or minimally invasive anterior approaches for en bloc tumor removal.Methods: O-arm navigation assisted osteotomies were carried out to remove a Th.V. breast tumor metastasis en bloc, intact bony part of the Th.V. vertebra was spared. Vertebral corpectomies of a patient with L.IV. chordoma and of a patient with L.V. carcinoid were also performed using minimally invasive, microscope assisted, anterior approaches to the lumbar spine.Results: No morbidity or local recurrence were detected in the patient with breast cancer 1 year after the operation. Nevertheless, new spinal metastasis were revealed 1 year after surgery despite the appropriate oncological treatment. The patient with L.IV. chordoma is still tumor free (last follow-up: 18 month after surgery), but post operatively detected lower limb paresis and gait disturbances are persisted. The posterior healthy bony parts of the spinal column remained intact, since only anterior approaches were used for en bloc L.IV. corpectomy. No morbidity or recurrence was detected in patient with L.V. carcinoid tumor on 1 year follow-up.Conclusion: Both the O-arm navigation assisted surgery and the minimally invasive anterior approaches to the spine can help to reduce surgical morbidity and to spare healthy bony structures of the spine. The later could play important role to provide long term spine stability. The presented new surgical technologies can be accepted only, if they produce at least the same oncological results on longer follow-ups as conventional surgical approaches.
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| 10. |
- Szabó, Viktor, et al.
(författare)
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Percutaneous Spine Fusion Combined with Whole-Body Traction in the Acute Surgical Treatment of AO A- and C-Type Fractures : A Technical Note
- 2022
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Ingår i: World Neurosurgery. - : Elsevier. - 1878-8750 .- 1878-8769. ; 159, s. 13-26
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A diminished level of pain following the operation and shortened hospitalization are the distinct However, manipulating the spine with additional MISS tools (e.g., distraction and compression devices) is often cumbersome. Our paper draws attention to a cost-free, fast, indirect decompression method that can be used in the acute treatment of thoracolumbar spine fractures. The presented method involves ligamentotaxis by whole-body traction in the operating room combined with percutaneous spine fixation.METHODS: Fifteen patients with thoracolumbar injuries A type and C type (without distraction) by AO classification were operated sequentially with the combination of wholebody traction and percutaneous minimally invasive spine fixation. Data were analyzed retrospectively.RESULTS: A total of 139 screws were implanted into 70 segments in 6 female and 9 male patients. The average clinical follow-up was 16 months. Average preoperative traumatic kyphosis was 17 degrees, and an average postoperative kyphosis was 1.8 degrees. The fractured vertebrae's height gain was an average of 11.0 mm (range 3.921.9 mm) ventrally and an average of 5.4 mm (range 1-11.2 mm) dorsally after the surgeries. The spinal canal space narrowing showed an average 6.5 mm improvement postoperatively. Operative time averaged 2 hours and 34 miwere observed.CONCLUSIONS: The combination of MISS and whole-body traction provided successful anatomical correction in thirteen of the fifteen cases of compression type thor-acolumbar fractures without extensive surgical exploration.
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