Direct Visualization of Mechanical Beats by Means of an Oscillating Smartphone

[EN] The resonance phenomenon is widely known in physics courses.1 Qualitatively speaking, resonance takes place in a driven oscillating system whenever the frequency approaches the natural frequency, resulting in maximal oscillatory amplitude. Very closely related to resonance is the phenomenon of mechanical beating, which occurs when the driving and natural frequencies of the system are slightly different. The frequency of the beat is just the difference of the natural and driving frequencies. Beats are very familiar in acoustic systems. There are several works in this journal on visualizing the beats in acoustic systems.2¿4 For instance, the microphone and the speaker of two mobile devices were used in previous work2 to analyze the acoustic beats produced by two signals of close frequencies. The formation of beats can also be visualized in mechanical systems, such as a mass-spring system5 or a double-driven string.6 Here, the mechanical beats in a smartphone-spring system are directly visualized in a simple way. The frequency of the beats is measured by means of the acceleration sensor of a smartphone, which hangs from a spring attached to a mechanical driver. This laboratory experiment is suitable for both high school and first-year university physics courses.The authors would like to thank the Institute of Educational Sciences of the Universitat Politecnica de Valencia (Spain) for the support of the Teaching Innovation Groups MoMa and e-MACAFI and for the financial support through the Project PIME 2015 B18.Giménez Valentín, MH.; Salinas Marín, I.; Monsoriu Serra, JA.; Castro-Palacio, JC. (2017). Direct Visualization of Mechanical Beats by Means of an Oscillating Smartphone. The Physics Teacher. 55(7):424-425. https://doi.org/10.1119/1.5003745S42442555

Interfascial Dissection For Protection Of The Nerve Branches To The Frontalis Muscles During Supraorbital Trans-eyebrow Approach: An Anatomical Study And Technical Note

Preservation of the temporal branches of the facial nerve during anterolateral craniotomies is important. Damaging it can inflict undesirable cosmetic defects to the patient. The supraorbital trans-eyebrow approach (SOTE) is a versatile keyhole craniotomy but still has a high rate of frontalis muscle (FM) palsy. Objective Anatomical study to implement the interfascial dissection during the SOTE to preserve the nerves to the FM. Methods Slight modification of the standard technique of the SOTE was performed in 6 cadaveric specimens (12 sides). Results Distal rami to the FMwere exposed. The standard "U-shape" incision of the FM can cross over the nerves. Alternatively, an "L-shape" incision was performed until the superior temporal line (STL). An interfascial dissection was performed near to the STL and the interfascial fat pad was used as a protective layer for the nerves. Conclusion Various pathologies can be addressed with the SOTE. In the majority of the cases the cosmetic results are good, but FM palsy remains a drawback of this approach. The interfascial dissection may be used in an attempt to prevent frontalis rami palsy.77326527

Acceptance Ordering Scheduling Problem: The impact of an order-portfolio on a make-to-order firm’s profitability

Firms’ growth, the darling measure of investors, comes from higher revenues. Thus, sales and marketing departments make extreme efforts to accept as many customer orders as possible. Unfortunately, not all orders contribute equally to profits, and some orders may even reduce net profits. Thus, saying no (i.e., not accepting an order) may be a necessary condition for net profits growth. For understanding the impact of rejecting orders on profitability, we propose an order acceptance and scheduling problem (OAS). Although the OAS has extensively been studied in the literature, there is still some gap between these papers and real-life problems in industry. In an attempt to close that gap, the OAS we propose considers orders revenues, machines costs, holding costs and tardiness costs. We develop a mixed integer linear programming (MILP) model for solving this problem. Since the complexity of the problem makes it impossible for the MILP to solver large-scale instances, we also propose a metaheuristic algorithm. Numerical experiments show that the metaheuristic finds good quality solutions in short computational times. In the last part of the paper we confirm some managerial insights: higher holding and tardiness costs imply a lower acceptance of orders, forcing production has a concave negative impact on net profits, and accurately estimating costs is essential for good planning

Investigation of Coulomb dipole polarization effects on reactions involving exotic nuclei

We have analyzed elastic scattering angular distributions and total reaction cross sections of the exotic nuclei Li9,11 on Pb208, at energies below and above the Coulomb barrier. For this purpose, we have used an optical potential with no adjustable parameters, composed by the nuclear São Paulo potential, derived from the nonlocal nature of the interaction, and the Coulomb dipole polarization potential, derived from the semiclassical theory of Coulomb excitation. Within this formalism, we identified an unusual long-range absorption for the Li11+Pb208 system, which is dominated by the Coulomb interaction. We compare it to the absorption mechanisms observed for He6+Pb208 which, unlike those of Li11+Pb208, take place at small interacting distances, where both Coulomb and nuclear interactions are important. The proposed approach shows to be a fundamental basis to study reactions involving exotic nuclei

Enhanced thermal stability and fracture toughness of TiAlN coatings by Cr, Nb and V-alloying

The effect of metal alloying on mechanical properties including hardness and fracture toughness were investigated in three alloys, Ti~0.33Al0.50(Me)~0.17N (Me¿=¿Cr, Nb and V), and compared to Ti0.50Al0.50N, in the as-deposited state and after annealing. All studied alloys display similar as-deposited hardness while the hardness evolution during annealing is found to be connected to phase transformations, related to the alloy's thermal stability. The most pronounced hardening was observed in Ti0.50Al0.50N, while all the coatings with additional metal elements sustain their hardness better and they are harder than Ti0.50Al0.50N after annealing at 1100¿°C. Fracture toughness properties were extracted from scratch tests. In all tested conditions, as-deposited and annealed at 900 and 1100¿°C, Ti0.33Al0.50Nb0.17N show the least surface and sub-surface damage when scratched despite the differences in decomposition behavior and h-AlN formation. Theoretically estimated ductility of phases existing in the coatings correlates well with their crack resistance. In summary, Ti0.33Al0.50Nb0.17N is the toughest alloy in both as-deposited and post-annealed states.Peer ReviewedPostprint (author's final draft

On exploring weakly supervised domain adaptation strategies for semantic segmentation using synthetic data

Pixel-wise image segmentation is key for many Computer Vision applications. The training of deep neural networks for this task has expensive pixel-level annotation requirements, thus, motivating a growing interest on synthetic data to provide unlimited data and its annotations. In this paper, we focus on the generation and application of synthetic data as representative training corpuses for semantic segmentation of urban scenes. First, we propose a synthetic data generation protocol, which identifies key features affecting performance and provides datasets with variable complexity. Second, we adapt two popular weakly supervised domain adaptation approaches (combined training, fine-tuning) to employ synthetic and real data. Moreover, we analyze several backbone models, real/synthetic datasets and their proportions when combined. Third, we propose a new curriculum learning strategy to employ several synthetic and real datasets. Our major findings suggest the high performance impact of pace and order of synthetic and real data presentation, achieving state of the art results for well-known models. The results by training with the proposed dataset outperform popular alternatives, thus demonstrating the effectiveness of the proposed protocol. Our code and dataset are available at http://www-vpu.eps.uam.es/publications/WSDA_semantic/Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work is part of the preliminary tasks related to the SEGA-CV (TED2021-131643A-I00) and the HVD (PID2021-125051OB-I00) projects funded by the Ministerio de Ciencia e Innovacion of the Spanish Governmen