| 31. |
|
|
| 32. |
- Bickham, S., et al.
(författare)
-
Low cutoff G.657-compatible fiber for data center interconnects operating in the 1064 and 1310 nm windows
- 2020
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 11286
-
Konferensbidrag (refereegranskat)abstract
- Optical interconnects in data centers have traditionally used 850 nm GaAs-based vertical-cavity surface-emitting lasers (VCSELs) in combination with multimode fiber, having a reach up to 100 m in length. Longer links typically use standard single-mode fiber in conjunction with either InP-based edge-emitting lasers or silicon photonic transmitters operating in the 1310 nm or 1550 nm window. Single-mode GaAs-based VCSELs operating at 1064 nm offer another path for achieving longer system reach. Potential advantages of these VCSELs include better power efficiency, modulation speeds reaching 50 Gbps and large-scale fabrication volumes. The longer wavelength is also beneficial due to the lower attenuation and chromatic dispersion of optical fibers at that wavelength. However, one practical issue for single-mode transmission is that the G.657 standard for single-mode fiber requires that the 22-meter cable cutoff wavelength be less than 1260 nm, and these fibers are typically few-moded at 1064 nm. The large differences between the group velocities of the LP01 and LP11 modes can lead to degradation of the system performance due to multi-path interference if the higher order modes are present. To resolve this quandary, we have designed and validated the performance of a new optical fiber which is single-moded at wavelengths less than 1064 nm, but also has G.657-compliant mode field diameter and dispersion characteristics that enable it to be used in the 1310 nm window.
|
|
| 33. |
- Chen, Yuxi, et al.
(författare)
-
Global Three-Dimensional Simulation of Earth's Dayside Reconnection Using a Two-Way Coupled Magnetohydrodynamics With Embedded Particle-in-Cell Model : Initial Results
- 2017
-
Ingår i: Journal of Geophysical Research - Space Physics. - : AMER GEOPHYSICAL UNION. - 2169-9380 .- 2169-9402. ; 122:10, s. 10318-10335
-
Tidskriftsartikel (refereegranskat)abstract
- We perform a three-dimensional (3-D) global simulation of Earth's magnetosphere with kinetic reconnection physics to study the flux transfer events (FTEs) and dayside magnetic reconnection with the recently developed magnetohydrodynamics with embedded particle-in-cell model. During the 1 h long simulation, the FTEs are generated quasi-periodically near the subsolar point and move toward the poles. We find that the magnetic field signature of FTEs at their early formation stage is similar to a "crater FTE," which is characterized by a magnetic field strength dip at the FTE center. After the FTE core field grows to a significant value, it becomes an FTE with typical flux rope structure. When an FTE moves across the cusp, reconnection between the FTE field lines and the cusp field lines can dissipate the FTE. The kinetic features are also captured by our model. A crescent electron phase space distribution is found near the reconnection site. A similar distribution is found for ions at the location where the Larmor electric field appears. The lower hybrid drift instability (LHDI) along the current sheet direction also arises at the interface of magnetosheath and magnetosphere plasma. The LHDI electric field is about 8 mV/m, and its dominant wavelength relative to the electron gyroradius agrees reasonably with Magnetospheric Multiscale (MMS) observations.
|
|
| 34. |
- Czeiter, Endre, et al.
(författare)
-
Brain Injury Biomarkers May Improve the Predictive Power of the IMPACT Outcome Calculator
- 2012
-
Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert. - 0897-7151 .- 1557-9042. ; 29:9, s. 1770-1778
-
Tidskriftsartikel (refereegranskat)abstract
- Outcome prediction following severe traumatic brain injury (sTBI) is a widely investigated field of research. A major breakthrough is represented by the IMPACT prognostic calculator based on admission data of more than 8500 patients. A growing body of scientific evidence has shown that clinically meaningful biomarkers, including glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), and alpha II-spectrin breakdown product (SBDP145), could also contribute to outcome prediction. The present study was initiated to assess whether the addition of biomarkers to the IMPACT prognostic calculator could improve its predictive power. Forty-five sTBI patients (GCS score <= 8) from four different sites were investigated. We utilized the core model of the IMPACT calculator (age, GCS motor score, and reaction of pupils), and measured the level of GFAP, UCH-L1, and SBDP145 in serum and cerebrospinal fluid (CSF). The forecast and actual 6-month outcomes were compared by logistic regression analysis. The results of the core model itself, as well as serum values of GFAP and CSF levels of SBDP145, showed a significant correlation with the 6-month mortality using a univariate analysis. In the core model, the Nagelkerke R-2 value was 0.214. With multivariate analysis we were able to increase this predictive power with one additional biomarker (GFAP in CSF) to R-2 = 0.476, while the application of three biomarker levels (GFAP in CSF, GFAP in serum, and SBDP145 in CSF) increased the Nagelkerke R-2 to 0.700. Our preliminary results underline the importance of biomarkers in outcome prediction, and encourage further investigation to expand the predictive power of contemporary outcome calculators and prognostic models in TBI.
|
|
| 35. |
- Daldorff, Lars K. S., et al.
(författare)
-
Two-way coupling of a global Hall magnetohydrodynamics model with a local implicit particle-in-cell model
- 2014
-
Ingår i: Journal of Computational Physics. - : Elsevier BV. - 0021-9991 .- 1090-2716. ; 268, s. 236-254
-
Tidskriftsartikel (refereegranskat)abstract
- Computational models based on a fluid description of the plasma, such as magnetohydrodynamic (MHD) and extended magnetohydrodynamic (XMHD) codes are highly efficient, but they miss the kinetic effects due to the assumptions of small gyro radius, charge neutrality, and Maxwellian thermal velocity distribution. Kinetic codes can properly take into account the kinetic effects, but they are orders of magnitude more expensive than the fluid codes due to the increased degrees of freedom. If the fluid description is acceptable in a large fraction of the computational domain, it makes sense to confine the kinetic model to the regions where kinetic effects are important. This coupled approach can be much more efficient than a pure kinetic model. The speed up is approximately the volume ratio of the full domain relative to the kinetic regions assuming that the kinetic code uses a uniform grid. This idea has been advocated by [1] but their coupling was limited to one dimension and they employed drastically different grid resolutions in the fluid and kinetic models. We describe a fully two-dimensional two-way coupling of a Hall MHD model BATS-R-US with an implicit Particle-in-Cell (PIC) model iPIC3D. The coupling can be performed with identical grid resolutions and time steps. We call this coupled computational plasma model MHD-EPIC (MHD with Embedded PIC regions). Our verification tests show that MHD-EPIC works accurately and robustly. We show a two-dimensional magnetosphere simulation as an illustration of the potential future applications of MHD-EPIC.
|
|
| 36. |
- Dehlin, S., et al.
(författare)
-
Practical application of a newly developed automated building energy-analysis software module prototype
- 2012
-
Ingår i: eWork and eBusiness in Architecture, Engineering and Construction. - Boca Raton : CRC Press, Taylor & Francis Group. - 9780415621281 ; , s. 45-49
-
Konferensbidrag (refereegranskat)abstract
- One key challenge when it comes to developing industrial building concepts for the housing industry is improving the energy performance of buildings, while at the same time ensuring that the end product remains affordable and attractive to customers. This paper summarises the findings from the application of a newly developed prototype for an automated energy-analysis software module in a real-life project.The prototype is used for the energy analysis of the low-energy, multi-family residential P303 concept developed by NCC Construction Sverige AB - a leading construction and development company in the Nordic region. A building concept is based on continuity and repetitions of most of the building components. Most of its characteristics are known and defined beforehand and only a few parameters vary due to the adaptation of the concept, for example, the configuration or site location. In energy performance calculations, the proposed energy-analysis software module prototype processes the known parameters as constants and only varies the unknown parameters. The energy calculations are then carried out by the calculation kernel from the dynamic building simulation software module, VIP Energy, and the result is exported to an Excel spreadsheet where it is presented in a table. This makes it possible, in a practical manner, to execute a larger number of performance analyses in a shorter time, investigating different design alternatives and configurations and thereby facilitating optimisation towards the best possible design solution. The case study presented in this paper simulated energy losses through the building envelope of a real P303 building. The parameters that were varied are the location and orientation of the building and various energy characteristics of windows/glazing.
|
|
| 37. |
- Desalegn, Anteneh, et al.
(författare)
-
Urinary concentrations of phthalate/DINCH metabolites and body mass index among European children and adolescents in the HBM4EU Aligned Studies: A cross-sectional multi-country study
- 2024
-
Ingår i: ENVIRONMENT INTERNATIONAL. - 0160-4120 .- 1873-6750. ; 190
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Phthalates are ubiquitous in the environment. Despite short half-lives, chronic exposure can lead to endocrine disruption. The safety of phthalate substitute DINCH is unclear. Objective: To evaluate associations between urinary concentrations of phthalate/DINCH metabolites and body mass index (BMI) z-score among children and adolescents. Method: We used Human Biomonitoring for Europe Aligned Studies data from 2876 children (12 studies, 6-12 years, 2014-2021) and 2499 adolescents (10 studies, 12-18 years, 2014-2021) with up to 14 phthalate/DINCH urinary metabolites. We used multilevel linear regression to assess associations between phthalate/DINCH concentrations and BMI z-scores, testing effect modification by sex. In a subset, Bayesian kernel machine regression (BKMR) and quantile-based g-computation assessed important predictors and mixture effects. Results: In children, we found few associations in single pollutant models and no interactions by sex (p p-interaction > 0.1). BKMR detected no relevant exposures (posterior inclusion probabilities, PIPs < 0.25), nor joint mixture effect. In adolescent single pollutant analysis, mono-ethyl phthalate (MEP) concentrations were associated with higher BMI z-score in males ((3 = 0.08, 95% CI: 0.001,0.15, per interquartile range increase in ln-transformed concentrations, p-interaction = 0.06). Conversely, mono-isobutyl phthalate (MiBP) was associated with a lower BMI z-score in both sexes ((3 =-0.13, 95 % CI:-0.19,-0.07, p-interaction = 0.74), as was sum of di(2-ethylhexyl) phthalate (& sum;DEHP) metabolites in females only ((3 =-0.08,95 % CI:-0.14,-0.02,p-interaction p-interaction = 0.01). In BKMR, higher BMI z-scores were predicted by MEP (PIP=0.90) and MBzP (PIP=0.84) in males. Lower BMI z-scores were predicted by MiBP (PIP=0.999), OH-MIDP (PIP=0.88) and OH-MINCH (PIP=0.72) in both sexes, less robustly by DEHP (PIP=0.61) in females. In quantile g-computation, the overall mixture effect was null for males, and trended negative for females ((3 =-0.11, 95 % CI:-0.25, 0.03, per joint exposure quantile). Conclusion: In this large Europe-wide study, we found age/sex-specific differences between phthalate metabolites and BMI z-score, stronger in adolescents. Longitudinal studies with repeated phthalate measurements are needed.
|
|
| 38. |
- Dutz, H, et al.
(författare)
-
Experimental check of the Gerasimov-Drell-Hearn sum rule for H-1
- 2004
-
Ingår i: Physical Review Letters. - 1079-7114. ; 93:3
-
Tidskriftsartikel (refereegranskat)abstract
- For the first time we checked the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the proton experimentally in the photon energy range from 0.2-2.9 GeV with the tagged photon facilities at MAMI (Mainz) and ELSA (Bonn). New data of the doubly polarized total cross section difference are presented in the energy range from 1.6 to 2.9 GeV. The contribution to the GDH integral from 0.2-2.9 GeV yields [254+/-5(stat)+/-12(syst)] mub with negative contributions in the Regge regime at photon energies above 2.1 GeV. This trend supports the validity of the GDH sum rule.
|
|
| 39. |
- Dutz, H, et al.
(författare)
-
First measurement of the Gerasimov-Drell-Hearn sum rule for H-1 from 0.7 to 1.8 GeV at ELSA
- 2003
-
Ingår i: Physical Review Letters. - 1079-7114. ; 91:19: 192001
-
Tidskriftsartikel (refereegranskat)abstract
- To verify the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the first time experimentally, we measured the helicity dependent total photoabsorption cross section with circularly polarized real photons and longitudinally polarized nucleons in the photon energy range 0.68-1.82 GeV with the tagged photon facility at ELSA. The experiment was carried out with a 4pi detection system, a circularly polarized tagged photon beam, and a frozen spin polarized proton target. The contribution to the GDH sum rule in this photon energy range is [49.9+/-2.4(stat)+/-2.2(syst)] mub.
|
|
| 40. |
- Dutz, H, et al.
(författare)
-
Measurement of helicity-dependent photoabsorption cross sections on the neutron from 815 to 1825 MeV
- 2005
-
Ingår i: Physical Review Letters. - 1079-7114. ; 94
-
Tidskriftsartikel (refereegranskat)abstract
- Helicity-dependent total photoabsorption cross sections on the deuteron have been measured for the first time at ELSA (Bonn) in the photon energy range from 815 to 1825 MeV. Circularly polarized tagged photons impinging on a longitudinally polarized LiD target have been used together with a highly efficient 4 pi detector system. The data around 1 GeV are not compatible with predictions from existing multipole analyses. From the measured energy range an experimental contribution to the GDH integral on the neutron of [33.9 +/- 5.5(stat)+/- 4.5(syst)] mu b is extracted.
|
|
