Precise models of the impact of explosions in urban environments provide novel and valuable information in disaster management for developing precautionary, preventive and mitigating measures. Yet to ...date, no methods enabling accurate predictions of the process and effect of detonations at particular locations exist. We propose a novel approach mitigating this gap by combining state-of-the-art methods from photogrammetric 3D reconstruction, semantic segmentation and computational based numerical simulations. In a first step, we create an accurate urban 3D reconstruction from georeferenced aerial images. The resulting city model is then enriched with semantic information obtained from the original source images as well as from registered terrestrial images using deep neural networks. This allows for an efficient automatic preparation of a 3D model suitable for the use as a geometry for the numerical investigations. Using this approach, we are able to provide recent and precise models of an area of interest in an automated fashion. Within the model, we are now able to define the explosive charge size and location and simulate the resulting blast wave propagation using CFD simulation. This provides a full estimation for the expected pressure propagation of a defined charge size. From these results, arising damages and their extent, as well as possible access routes or countermeasures, can be estimated. Using georeferenced sources allows for the integration and utilization of simulation results into existing geoinformation systems of disaster management units, providing novel inputs for training, preparation and prevention. We demonstrate our proposed approach by evaluating expected glass breakage and expected damages impairing the structural integrity of buildings depending on the charge size using a 3D reconstruction from aerial images of an area in the inner city of Graz, Austria.
A
bstract
We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle
ϕ
3
(also known as
γ
) using a model-independent Dalitz plot analysis of
B
+
→
D
(
K
S
0
h
+
h
−
)
h
+
, ...where
D
is either a
D
0
or
D
¯
0
meson and
h
is either a
π
or
K
. This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb
−
1
and 128 fb
−
1
, respectively. All data were accumulated from energy-asymmetric
e
+
e
−
collisions at a centre-of-mass energy corresponding to the mass of the Υ(4
S
) resonance. We measure
ϕ
3
= (78
.
4 ± 11
.
4 ± 0
.
5 ± 1
.
0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the
D
-decay strong-phase parameters.
A search for the flavor-changing neutral-current decay B+ →K+$ν\bar{ν}$ is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample ...corresponds to an integrated luminosity of 63 fb-1 collected at the Υ (4S) resonance and a sample of 9 fb-1 collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B+ →K+$ν\bar{ν}$ decay, but also the inclusive properties of the other B meson in the Υ(4S) $B\bar{B}$ event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B+ →K+$ν\bar{ν}$ of 4.1 × 10-5 is set at the 90% confidence level.
Objectives: Currently, no intracorporeal left ventricular assist device (LVAD) is commercially available for small pediatric patients. The requirements of small size and excellent hemocompatibility ...at low-flow conditions pose a distinct challenge for the development of a pediatric LVAD. This study aimed to assess the feasibility of a novel, miniaturized two-stage pump to meet these specific requirements. Methods: The design of the novel pediatric LVAD features two pump stages with a back-to-back impeller as a single rotating part. The impeller is hydrodynamically suspended in the radial direction and axially centered through reluctance forces. This enables miniaturization together with a reduction in circumferential velocity while achieving the required pressure head. Computational fluid dynamics was used to evaluate the pump performance. Washout of the priming volume was assessed through a passive scalar transport and pump-induced blood trauma through a power law model for the normalized index of hemolysis (NIH). Results were compared to the performance of the state-of-the-art LVAD HeartMate3 under the same pediatric operating conditions. Results: The two-stage pump shows a pressure head of 55mmHg at a flow rate of 1.5L/min with a circumferential velocity of 3.7m/s at a hydraulic efficiency of 33%. With a total priming volume of 3.7mL a washout of 95% is obtained in 0.17s, and the predicted NIH is 4.0mg/100L. In comparison, the HeartMate3 reaches a 95% washout of its 14.5mL priming volume after 0.86s with an NIH of 6.7mg/100L at a circumferential velocity of 4.1m/s. Conclusions: The proposed two-stage pump builds up the required pressure head at a smaller size and reduced circumferential velocity, resulting in improved numerical hemocompatibility metrics compared to the HeartMate3 at pediatric operating conditions. Further in vitro experiments will be performed to validate the numerical results. Overall, the two-stage pump may successfully tackle the low-flow challenges for pediatric LVADs.
We present measurements of the first to fourth moments of the lepton mass squared $q$2 of $B$ → $X_cℓ\overline{ν}_ℓ$ decays for $ℓ = e, μ$ and with $X_c$ a hadronic system containing a charm quark. ...These results use a sample of electron-positron collisions at the $Υ$($4S$) resonance corresponding to 62.8 fb-1 of integrated luminosity and collected by the Belle II 2 experiment in 2019 and 2020. To identify the $X_c$ system and reconstruct $q$2, one of the $B$ mesons from an $Υ$($4S$) → $B\overline{B}$ decay is fully reconstructed in a hadronic decay mode using a multivariate $B$ tagging algorithm. We report raw and central moments for $q$2 > 1.5 $GeV$2=$c$4 up to $q$2 > 8.5 $GeV$2=$c$4, probing up to 77% of the accessible $B$ → $X_cℓ\overline{ν}_ℓ$ phase space. This is the first measurement of moments in the experimentally challenging range of 1.5; 2.5 $GeV$2=$c$4. The results can be used for a new determination of |$V_{cb}$| using inclusive $B$ → $X_cℓ\overline{ν}_ℓ$ decays.
Measurements of beam backgrounds in SuperKEKB Phase 2 Liptak, Z.; Paladino, A.; Santelj, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2022, Letnik:
1040
Journal Article
Recenzirano
Odprti dostop
The high design luminosity of the SuperKEKB electron–positron collider will result in challenging levels of beam-induced backgrounds in the interaction region. Understanding and mitigating these ...backgrounds is critical to the success of the Belle II experiment. We report on the first background measurements performed after roll-in of the Belle II detector, a period known as SuperKEKB Phase 2, utilizing both the BEAST II system of dedicated background detectors and the Belle II detector itself. We also report on first revisions to the background simulation made in response to our findings. Backgrounds measured include contributions from synchrotron radiation, beam-gas, Touschek, and injection backgrounds. At the end of Phase 2, single-beam backgrounds originating from the 4 GeV positron Low Energy Ring (LER) agree reasonably well with simulation, while backgrounds from the 7 GeV electron High Energy Ring (HER) are approximately one order of magnitude higher than simulation. We extrapolate these backgrounds forward and conclude it is safe to install the Belle II vertex detector.
We present a measurement of the τ-lepton mass using a sample of about 175 million
$e^+$$e^-$ → ${{\tau}}^+{{\tau}}^-$ events collected with the Belle II detector at the SuperKEKB $e^+$$e^-$ collider ...at a center-of-mass energy of 10.579GeV. This sample corresponds to an integrated luminosity of $190$ $\mathrm{fb}$$^{-1}$. We use the kinematic edge of the ${{\tau}}$ pseudomass distribution in the decay ${{\tau}}^-$ → $π^-π^+π^-ν_τ$ and measure the ${{\tau}}$ mass to be $1777.09±0.08±0.11$ $\mathrm{MeV}$ $/{c^2}$, where the first uncertainty is statistical and the second systematic. This result is the most precise to date.
Abstract We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle ϕ 3 (also known as γ) using a model-independent Dalitz plot analysis of B + → D ( K S 0 $$ {K}_S^0 $$ h + h ...− )h +, where D is either a D 0 or D ¯ $$ \overline{D} $$ 0 meson and h is either a π or K. This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb −1 and 128 fb −1, respectively. All data were accumulated from energy-asymmetric e + e − collisions at a centre-of-mass energy corresponding to the mass of the Υ(4S) resonance. We measure ϕ 3 = (78.4 ± 11.4 ± 0.5 ± 1.0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the D-decay strong-phase parameters.
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