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AI for Particle Physics
Published in Volker Knecht, AI for Physics, 2023
Mario Campanelli, Volker Knecht
In string theory, the point-like particles of the SM are superseded by one-dimensional objects called strings.8 Bosonic string theory contained only bosons. In contrast, supersymmetric string theory – or superstring theory for short – accounts for both fermions and bosons and integrates supersymmetry to model gravity. This theory may also explain the observed forces and particles of the SM, justify their masses, and shed light on the nature of dark matter plus dark energy. In that sense, it provides a theory of everything (check out Chapter 8).
Tetrahedral Dual Coordinate System: The Static and Dynamic Algebraic Model
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
String Theory represents the existence of extra dimensions, such as six and ten dimensions, without a primary coordinate system to mathematically describe the quantum properties of physics. The DCS includes the dimensions of atomic space with three and six dimensions. There are also four axes of rotational symmetry which explain the unique properties of the quasicrystals which have fifteen extra dimensions in the icosahedron and pentagonal dodecahedron. Examples of 6D engineering and architecture are observed in the tetrahedron and octahedron truss system in the Paris Louvre and the Leonardo Da Vinci Airport Rome.
Nano- and Microscale Systems, Devices, and Structures
Published in Sergey Edward Lyshevski, Nano- and Micro-Electromechanical Systems, 2018
In this book, we will utilize the so-called standard model (particles are considered to be points moving through space and coherently represented by mass, electric charge, interaction, spin, etc.), see Fig. 2.5. The standard model was developed within a quantum field theory paradigm that is consistent with quantum mechanics and the special theory of relativity. Electromagnetism and the strong and weak nuclear forces are integrated. However, the gravity (fourth interaction) from Einstein’s general relativity theory does not fit into quantum field theory. In fact, the quantum field theory and general relativity cannot be integrated. To overcome these limits, string theory has been developed. In string theory, instead of particles, one utilizes a fundamental building block called a string that can be closed (loop) or open. As the string moves through time, it traces out a tube (closed string) or a sheet (open string). The string is free to vibrate, and different vibration modes of the string represent the different particle types, since different modes are seen as different masses or spins. For example, modes of vibration (notes) may represent electrons or photons. String theory provides a consistent unified method that integrates electromagnetism, strong and weak nuclear forces, and gravity. The particles known in nature are classified according to their spin into bosons (integer spin) or fermions (odd half-integer spin). Examining the forces, we emphasize that the photon carries electromagnetic force, the gluon carries the strong nuclear force, and the graviton carries the gravitational force. Recently, superstrings and heterotic string theories have been introduced, and many other concepts have emerged. The unified paradigm is called the M-theory. We usually apply three dimensions of space and one of time. String theory utilizes 10-dimensional space and time. These extra dimensions, which can confuse the reader, could be unobservable, but compact dimensions result from mathematical deviations.
Instantaneous identification of tension in bridge cables using synchrosqueezing wave-packet transform of acceleration responses
Published in Structure and Infrastructure Engineering, 2022
Xin Zhang, Ye Lu, Maosen Cao, Shuai Li, Dragoslav Sumarac, Zeyu Wang
The remarkable capability of the proposed SWIFT algorithm can be summarized as follows: (1) high resolution in ifs identification, (2) restraining the negative influence of uncertainty principle, (3) notable ability for noise immunity. The theoretical, numerical, and experimental results show that the SWIFT algorithm is capable of identifying the instantaneous tension change of long cables with viscous dampers under time-varying loads. The proposed algorithm holds promise for real-time condition monitoring of cable-supported bridges. The limitation of the proposed algorithm is mainly twofold: (1) The proposed algorithm is essentially underpinned by the taut-string theory. This theory is valid for long cables while invalid for short cables. Hence, the proposed algorithm is inapplicable to short cables. (2) The accuracy of the proposed algorithm primarily relies on the identification resolution of instantaneous frequencies. Based on present studies, a 6-second sampling duration is an appropriate threshold of producing proper instantaneous frequencies used to identify cable tension.
Wind Induced Hanger Vibrations – the Hålogaland Suspension Bridge
Published in Structural Engineering International, 2022
Allan Larsen, Ken Grønne Andersen, Assad Jamal
The Fig. 7 frequency spectra yield information on the structural dynamics properties of hanger no. 55. The spectrum recorded for a wind speed of = 2.4 m/s displays a series of harmonic peaks at frequencies 2.930, 3.662, 4.395 and 5.127 Hz, the increment in frequency 0.732 Hz obtained by subtracting two neighbouring frequencies is identified, as is the basic frequency of the hanger. Taut string theory yields the speed of bending waves travelling down the hanger as Thus, the length of the sinusoidal loop of the n′th mode is calculated as For hanger no. 55, the length of the hanger cable is = 122 m. Inserting the basic frequency = 0.732 Hz in (1) yields = 178.6 m/s, which in turn allows evaluation of the axial tension force due to deadload to be = 957 kN taking = 30 kg/m. The estimated axial tension is in good agreement with the design value of 1050 kN.
Predicting fatigue damage of highway suspension bridge hangers using weigh-in-motion data and machine learning
Published in Structure and Infrastructure Engineering, 2021
Yang Deng, Meng Zhang, Dong-Ming Feng, Ai-Qun Li
The widely used vibration-based tension force estimate method, mostly based on the taut string theory or beam theory, utilises a direct relationship between cable natural frequencies and tension forces. However, this method can hardly provide continuous and time-varying cable tension forces. Therefore, methods for identifying the time-varying cable tension forces in real time have been developed (Bao, Shi, Beck, Li, & Hou, 2017; Li, Zhang, & Jin, 2014; Yang, Li, Nagarajaiah, Li, & Zhou, 2016). However, the identified time-varying tension forces have not been used to evaluate the fatigue performance of cables or hangers. In addition, in recent years, optical fibre-based sensing technology has been developed for cable tension force monitoring (Lan, Li, & Ju, 2010; Li, Zhou, & Ou, 2012; Zheng et al., 2018). This technology has been used in cable-stayed bridge and tied-arch bridge. For most of suspension bridges, the optical fibre sensors have not been equipped in the hangers during their construction periods. Hence, a tension force estimation methodology for hangers of in-service suspension bridges is still in need.