Additive manufacturing technologies produce objects which present a characteristic surface texture. This is an inevitable and systematic error and has a predictable shape feature which depends on ...certain process parameters. In order to reduce manufacturing costs and obtain the best results from the point of view of quality, it is essential to predict this error in advance and choose the process parameters which minimise it. For the purpose of measuring the surface quality, the index
R
a
(ISO 4287, 1997) is used in the related literature. In this paper, it is first demonstrated that the use of roughness parameters in FDM-manufactured surfaces is not adequate to quantify the surface error. The parameter
P
a
(ISO 4287) is proposed as a more appropriate index to evaluate the surface quality; it is investigated and critically analysed in comparison with the
R
a
index. A new original model to predict
P
a
for FDM-manufactured surfaces is presented. The model prediction is compared with experimental data and with the estimation performed by the models described in the literature, within the limits of their capability to predict
P
a
.
We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS ...HVeV, a 0.93 g CDMS high-voltage device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1 MeV/c^{2}. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 g d). These results demonstrate the scientific potential of phonon-mediated semiconductor detectors that are sensitive to single electronic excitations.
The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting ...massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg day, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5 GeV/c^{2}.
Light-matter interaction, and the understanding of the fundamental physics behind, is the scenario of emerging quantum technologies. Solid state devices allow the exploration of new regimes where ...ultrastrong coupling strengths are comparable to subsystem energies, and new exotic phenomena like quantum phase transitions and ground-state entanglement occur. While experiments so far provided only spectroscopic evidence of ultrastrong coupling, we propose a new dynamical protocol for detecting virtual photon pairs in the dressed eigenstates. This is the fingerprint of the violated conservation of the number of excitations, which heralds the symmetry broken by ultrastrong coupling. We show that in flux-based superconducting architectures this photon production channel can be coherently amplified by Stimulated Raman Adiabatic Passage, providing a unique tool for an unambiguous dynamical detection of ultrastrong coupling in present day hardware. This protocol could be a benchmark for control of the dynamics of ultrastrong coupling architectures, in view of applications to quantum information and microwave quantum photonics.
We report the result of a blinded search for weakly interacting massive particles (WIMPs) using the majority of the SuperCDMS Soudan data set. With an exposure of 1690 kg d, a single candidate event ...is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP-nucleon cross section of 1.4×10^{-44} (1.0×10^{-44}) cm^{2} at 46 GeV/c^{2}. These results set the strongest limits for WIMP-germanium-nucleus interactions for masses >12 GeV/c^{2}.
We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30 ...GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42) cm(2) at 8 GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6 GeV/c(2).
SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present ...WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c2.
This review covers direct searches for dark matter, and the role inorganic scintillators have to play in them. Particle dark matter may make up most of the matter in the universe. Direct searches for ...dark matter are progressing thanks to improvements in detector technology. The phase space predicted by various theories is vast. Noble-element based detectors, soon weighing one ton, seem best-placed to search for relatively heavy ( >~20 GeV) particles, and have already probed dark matter-nucleon cross sections as small as 7 ×10 -46 cm 2 . A variety of other technologies, including cryogenic detectors, gaseous ones and CCDs, will cover lower masses (down to 1 GeV or less), where recent hints for a discovery have been seriously undermined. Background rejection is essential in this field. Inorganic scintillators have roles to play at cryogenic temperatures, where the scintillation signal can be coupled to a measurement of phonons, providing particle identification. Future experiments with highly radiopure and high light yield NaI(Tl) can contribute to direct investigation of the longstanding detection claim from DAMA/LIBRA.
An automatic method for pottery fragments analysis Di Angelo, L.; Di Stefano, P.; Pane, C.
Measurement : journal of the International Measurement Confederation,
November 2018, 2018-11-00, 20181101, Letnik:
128
Journal Article
Recenzirano
•A new computer-aided method aimed to analyse pottery fragments is proposed.•Starting from a 3D discrete model, it analyses geometrical differential properties.•It firstly segments fragment in ...typical geometrical and morphological features.•Then it proceeds with the dimensional analysis of selected recognised features.•The results shown an accuracy and robustness not achievable with traditional method.
With the aim to reduce the uncertainties of the traditional archaeological approach and reduce costs for ceramic investigation, in this paper a computer-based method is proposed. A discrete geometric model of a pottery fragment is the starting input, from which a first distinction in axially and not-axially symmetric surfaces can be done. Geometrical and morphological features are then recognized. Only once that all this information is obtained, it is possible to proceed with the dimensional analysis. The analysis carried on the test case here illustrated proves that the automatic method presents accuracy and robustness not achievable even using the best application of the archaeological method. This method seems to be functional to other goals, such as for pottery classification and reconstruction of ancient ceramics.
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