DSpace Collection:
http://hdl.handle.net/10261/388
2024-03-28T11:19:10ZAge-related changes in the viscoelasticity of rabbit lens characterised by surface wave dispersion analysis
http://hdl.handle.net/10261/350824
Título: Age-related changes in the viscoelasticity of rabbit lens characterised by surface wave dispersion analysis
Autor: Zhang, H.; Singh, M.; Zvietcovich, Fernando; Larin, K.; Aglyamov, S.
Resumen: The viscoelastic properties of the young and mature rabbit lenses in situ are evaluated using wave-based optical coherence elastography (OCE). Surface waves in the crystalline lens are generated using acoustic radiation force (ARF) focused inside the eyeball. Surface-wave dispersion is measured with a phase-stabilised optical coherence tomography (OCT) system. The Young's modulus and shear viscosity coefficient are quantified based on a Scholte wave model. The results show that both elasticity and viscosity are significantly different between the young and mature lenses. The Young's modulus of the lenses increased with age from 7.74 ± 1.56 kPa (young) to 15.15 ± 4.52 kPa (mature), and the shear viscosity coefficient increased from 0.55 ± 0.04 Pa s (young) and 0.86 ± 0.13 Pa s (mature). It is shown that the combination of ARF excitation, OCE imaging, and dispersion analysis enables nondestructive quantification of lenticular viscoelasticity in situ and shows promise for in vivo applications.
Descripción: 6 pags., 5 figs., 1 tab.2024-03-18T15:10:03ZWASA-FRS HypHI experiment at GSI for studying light hypernuclei - Hiroyuki Ekawaa for WASA-FRS Collaboration
http://hdl.handle.net/10261/350821
Título: WASA-FRS HypHI experiment at GSI for studying light hypernuclei - Hiroyuki Ekawaa for WASA-FRS Collaboration
Autor: Rappold, Christophe; Escrig, S.
Resumen: . From January till March 2022, the WASA-FRS HypHI experiment
performed a precise measurement of the hypertriton and the 4
ΛH hypernucleus
lifetime at GSI. The data collected should also confirm whether or not the nnΛ
bound state can exist. The experiment were carried out with the WASA central
detector with a complex of additional dedicated detectors mounted together at
the mid-focal plane of the high-momentum-resolution forward spectrometer,
the so-called fragment separator FRS. Hypernuclei of interest were produced
by induced reactions of 6Li projectiles at 1.96 A GeV on a diamond target with a
thickness of 9.87 g/cm2
. Negatively charged π mesons from two-body decays of
the hypernuclei of interest were measured by the WASA and the other detectors,
and the residual nuclei after the π
− decay were measured by the FRS with a
momentum resolving power of 104
.
Descripción: Presentación con 17 dispositivas. -- 5 pags. 4 figs., 2 tabs. -- HYP2022 - 14th International Conference on Hypernuclear and Strange Particle Physics2024-03-18T15:00:06ZStudies of hypernuclei with heavy-ion beams, nuclear emulsions and machine learning - T. R. Saito, for the WASA-FRS collaboration and the Emulsion-ML collaboration
http://hdl.handle.net/10261/350815
Título: Studies of hypernuclei with heavy-ion beams, nuclear emulsions and machine learning - T. R. Saito, for the WASA-FRS collaboration and the Emulsion-ML collaboration
Autor: Rappold, Christophe
Resumen: The lightest hypernucleus, the hypertriton, has been a benchmark in
the field of hypernuclear physics. However, some of recent experiments employing energetic heavy-ion beams have revealed that the hypertriton lifetime
is significantly shorter than 263 ps which is expected by considering the known
weakly binding nature of the hypertriton. The STAR collaboration has also
measured the hypertriton binding energy, and the deduced value is contradicting to its formerly known small binding energy. These measurements have
indicated that the fundamental physics quantities of the hypertriton such as its
lifetime and binding energy have not been understood, therefore, they have to
be measured very precisely. Furthermore, an unprecedented Λnn bound state
observed by the HypHI collaboration has to be studied in order to draw a conclusion whether or not such a bound state exists. These three-body hypernuclear
states are studied by the heavy-ion beam data in the WASA-FRS experiment and
by analysing J-PARC E07 nuclear emulsion data with machine learning
Descripción: Presentación con 75 diapositivas, HYP2022, June 27th – July 1st, Prague, 20222024-03-18T14:30:05ZMechanical Characterization of Anhydrous Microporous Aluminophosphate Materials: Tridimensional Incompressibility, Ductility, Isotropy and Negative Linear Compressibility
http://hdl.handle.net/10261/350812
Título: Mechanical Characterization of Anhydrous Microporous Aluminophosphate Materials: Tridimensional Incompressibility, Ductility, Isotropy and Negative Linear Compressibility
Autor: Colmenero, Francisco; Lobato, A.; Timón, Vicente
Resumen: Here, a detailed mechanical characterization of five important anhydrous microporous aluminophosphate materials (VPI-5, ALPO-8, ALPO-5, ALPO-18, and ALPO-31) is performed using first principles methods based on periodic density functional theory. These materials are characterized by the presence of large empty structural channels expanding along several different crystallographic directions. The elasticity tensors, mechanical properties, and compressibility functions of these materials are determined and analyzed. All of these materials have a common elastic behavior and share many mechanical properties. They are largely incompressible at zero pressure, the compressibilities along the three crystallographic directions being frequently smaller than 5 (Formula presented.). Notably, the compressibilities of ALPO-5 and ALPO-31 along the three principal directions are smaller than this threshold. Likewise, the compressibilities of ALPO-18 along two directions are smaller than 5 (Formula presented.). All of the considered materials are shear resistant and ductile due to the large bulk to shear moduli ratio. Furthermore, all of these materials have very small mechanical anisotropies. ALPO-18 exhibits the negative linear compressibility (NLC) phenomenon for external pressures in the range P = 1.21 to P = 2.70 GPa. The minimum value of the compressibility along the [1 0 0] direction, (Formula presented.) 30.9 (Formula presented.), is encountered for P = 2.04 GPa. The NLC effect in this material can be rationalized using the empty channel structural mechanism. The effect of water molecule adsorption in the channels of ALPO-18 is assessed by studying the hydrated ALPO-18 material (ALPO-18W). ALPO-18W is much more compressible and less ductile than ALPO-18 and does not present NLC effects. Finally, the effect of aging and pressure polymorphism in the mechanical properties of VPI-5 and ALPO-5 is studied. As hydration, aging leads to significant variations in the elastic properties of VPI-5 and increases substantially its compressibility. For ALPO-5, pressure polymorphism has a small impact in its elasticity at zero pressure but a large influence at high pressure.
Descripción: 43 pags., 18 figs., 6 tabs.2024-03-18T14:10:04Z