Miracle-dz/UniFAR-FTUs huggingface dataset:
The propagation of Lamb waves in multilayered plates: phase-velocity measurement

Owing to the dispersive nature and complexity of the Lamb waves generated in a composite plate, the measurement of the phase velocities by using classical methods is complicated. This paper describes a measurement method based upon the spectrum-analysis technique, which allows one to overcome these problems. The technique consists of using the fast Fourier transform to compute the spatial power-density spectrum. Additionally, weighted functions are used to increase the probability of detecting the various propagation modes. Experimental Lamb-wave dispersion curves of multilayered plates are successfully compared with the analytical ones. This technique is expected to be a useful way to design composite parts integrating ultrasonic transducers in the field of health monitoring. Indeed, Lamb waves and particularly their velocities are very sensitive to defects.
Spherically symmetric inhomogeneous model with Chaplygin gas

We investigate the late time acceleration with a Chaplygin type of gas in spherically symmetric inhomogeneous model. At the early phase we get Einstien-de Sitter type of solution generalised to inhomogeneous spacetime. But at late stage of the evolution our solutions admit the accelerating nature of the universe. For a large scale factor our model behaves like a ΛCDM model. We calculate the deceleration parameter for this anisotropic model, which, unlike its homogeneous counterpart, shows that the flip is not synchronous occurring early at the outer shells. This is in line with other physical processes in any inhomogeneous models. Depending upon initial conditions our solution also gives bouncing universe. In the absence of inhomogeneity our solution reduces to wellknown solutions in homogeneous case. We have also calculated the effective deceleration parameter in terms of Hubble parameter. The whole situation is later discussed with the help of wellknown Raychaudhury equation and the results are compared with the previous case. This work is an extension of our recent communication where an attempt was made to see if the presence of extra dimensions and/or inhomogeneity can trigger an inflation in a matter dominated Lemaître Tolman Bondi model.
Automatic Multi-Model Fitting for Blood Vessel Extraction

Blood vessel extraction and visualization in 2D images or 3D volumes is an essential clinical task. A blood vessel system is an example of a tubular tree like structure, and fully automated reconstruction of tubular tree like structures remains an open computer vision problem. Most vessel extraction methods are based on the vesselness measure. A vesselness measure, usually based on the eigenvalues of the Hessian matrix, assigns a high value to a voxel that is likely to be a part of a blood vessel. After the vesselness measure is computed, most methods extract vessels based on the shortest paths connecting voxels with a high measure of vesselness. Our approach is quite different. We also start with the vesselness measure, but instead of computing shortest paths, we propose to fit a geometric of vessel system to the vesselness measure. Fitting a geometric model has the advantage that we can choose a model with desired properties and the appropriate goodness-of-fit function to control the fitting results. Changing the model and goodness-of-fit function allows us to change the properties of the reconstructed vessel system structure in a principled way. In contrast, with shortest paths, any undesirable reconstruction properties, such as short-cutting, is addressed by developing ad-hock procedures that are not easy to control. Since the geometric model has to be fitted to a discrete set of points, we threshold the vesselness measure to extract voxels that are likely to be vessels, and fit our geometric model to these thresholded voxels. Our geometric model is a piecewise-line segment model. That is we approximate the vessel structure as a collection of 3D straight line segments of various lengths and widths. This can be regarded as the problem of fitting multiple line segments, that is a multi-model fitting problem. We approach the multi-model fitting problem in the global energy optimization framework. That is we formulate a global energy function that reflects the goodness of fit of our piecewise line segment model to the thresholded vesselness voxels and we use the efficient and effective graph cut algorithm to optimize the energy. Our global energy function consists of the data, smoothness and label cost. The data cost encourages a good geometric fit of each voxel to the line segment it is being assigned to. The smoothness cost encourages nearby line segments to have similar angles, thus encouraging smoother blood vessels. The label cost penalizes overly complex models, that is, it encourages to explain the data with fewer line segment models. We apply our algorithm to the challenging 3D data that are micro-CT images of a mouse heart and obtain promising results.
Designing for Compact Living Spaces: An Exploration Tool for the Ultimate Tiny House Experience

In recent years, the popularity of compact living spaces like Tiny Houses is rising in the Netherlands. With Tiny Houses still gaining in popularity, there is a demand for information and knowledge about this new form of living. Through multiple sources, interested people are learning about tiny living and how to realize living in a Tiny House. However, these sources only cover the 'what' and 'how' about a Tiny House and forget about the most important 'why' part: why does a Tiny House fit you and which aspects of living in a Tiny House are important to you? This project focuses on this 'why-gap' by designing an exploration tool that helps people to find their ultimate Tiny House experience and this way create a strong base for designing their own Tiny House. To gain knowledge about the context, target group, and existing Tiny Houses, multiple types of research are conducted. In a contextual research, Tiny House residents are asked to share their experiences to find out which different values can be distinguished per resident. In the user research, the target groups are defined to see how the tool could contribute to each of the different groups. The reference analysis is used to map out the different characteristic elements that determine the design and character of a Tiny House. From these researches, a design model arose, where the 'why' forms the base of the design, with the user and its values central. The 'how' builds on to this base, where the choices of the user as the determinants are central. Finally, these two layers serve as the foundation for the design of the Tiny House. The final design: Tiny Roots is a toolkit that can be used in a series of sessions, for users to explore their ultimate Tiny House experience by answering this 'why' and 'how' first before designing the 'what': the Tiny House itself. It serves as the roots for designing a Tiny House that meets all values and wishes, matches the personality of the resident and this way create the ultimate Tiny House experience.
On Poisson (co)homologies of

where f ∈ C∞(M), c(f) = df ⊥ π,X ∈ Υ∗(M), and [[ , ]] is the Schouten–Nijenhuis bracket [1], [6]. The Jacobi identity for the Poisson bracket { , } is equivalent to the condition δ2 = 0, which holds if [[π, π]] = 0. The complex ( Υ∗(M), δ ) is called a Poisson complex and its cohomology H∗ δ (M) is called the Poisson cohomology of the manifold M m [6]. Let K be a compact real form of a semisimple complex Lie group G and O the orbit of the coadjoint action in k∗. Consider O as the Poisson homogeneous space of the Poisson–Lie group K with the Sklyanin–Drinfel’d Poisson structure defined on K in the following way:
An inverse approach to the design of adaptive micro-mirrors

In this paper we describe a method for designing electrostatic MEMS/MOEMS such as deformable micro-mirrors. Starting from a given set of displacements of a thin flexible 2D structure, we first show how to deduce the corresponding required pressure distribution from the non-linear equations of Von Karman. After illustrating this method with a simple example, which yields analytical results, we use this result to treat the problem of the theoretical and practical calculations of the voltages corresponding to the pressure distribution.
Exact decay and tunnelling dynamics of interacting few-boson systems

In our paper we actually used a wavefunction-based nonescape probability of finding the full many-body quantum system in the desired region of the total space, rather than (as given in equation (8) of our paper) the density-based nonescape probability of finding a part of the total density in the desired region of the total space. Both quantities are of interest and provide relevant information on the system and the aproximations used. The differences are discussed in the associated PDF file, together with a new figure and some consequent corrections to the text.
ACCRETION ONTO BLACK HOLES FROM LARGE SCALES REGULATED BY RADIATIVE FEEDBACK. II. GROWTH RATE AND DUTY CYCLE

This paper, the second in a series on radiation-regulated accretion onto black holes (BHs) from galactic scales, focuses on the effects of radiation pressure and angular momentum of the accreting gas. We simulate accretion onto intermediate-mass black holes, but we derive general scaling relationships that are solutions of the Bondi problem with radiation feedback valid for any mass of the BH Mbh. Thermal pressure of the ionized sphere around the BH regulates the accretion rate, producing periodic and short-lived luminosity bursts. We find that for ambient gas densities exceeding ncrH, ∞∝M−1bh, the period of the oscillations decreases rapidly and the duty cycle increases from 6%, in agreement with observations of the fraction of active galactic nuclei at z ∼ 3, to 50%. The mean accretion rate becomes Eddington limited for nH, ∞ > nEddH, ∞ ≃ ncrH, ∞T∞, 4−1 where T∞, 4 is the gas temperature in units of 104 K. In the sub-Eddington regime, the mean accretion rate onto BHs is about 1%T2.5∞, 4 of the Bondi rate, and thus is proportional to the thermal pressure of the ambient medium. The period of the oscillations coincides with the depletion timescale of the gas inside the ionized bubble surrounding the BH. Gas depletion is dominated by a pressure gradient pushing the gas outward if nH, ∞ < ncrH, ∞ and by accretion onto the BH otherwise. Generally, for nH, ∞ < ncrH, ∞ angular momentum does not significantly affect the accretion rate and period of the oscillations.
Design of Review Systems – A Strategic Instrument to Shape Online Reviewing Behavior and Economic Outcomes

As online reviews play a decisive role in consumers’ purchase decisions, e-commerce platforms such as Amazon or Yelp are using review systems strategically to obtain a competitive advantage. However, prospective consumers can only learn from others’ experiences if the review system is designed appropriately. Research on the design of review systems and the effects of design choices has not yet been summarized and synthesized in a review article. We aim to close this gap by providing a scoping review. In our synthesis, we posit that the design of review systems moderates the impact of online reviews on economic outcomes and the factors that drive the formation of reviews. After consolidating the existing research results, we identify research gaps and provide a research agenda covering three different dimensions: (1) Review system design features, (2) Review system design for different environments, and (3) Review system design for different devices. Finally, we discuss the strategic implications of review system design from the perspective of the resource-based view of the firm.
In situ observation on microstructure evolution of 22MnB5 in hot stamping process

High temperature confocal laser scanning microscopy (CLSM) was used to investigate the microstructure evolution of high-strength boron steel 22MnB5 during hot stamping. The experimental results show that it is complete austenitized at temperatures about 810 °C during the heating process. Most of the initial austenite grain size is small and locally coarse. At 920 °C to 1000 °C, the phenomenon of B remelted and solidified was observed which played a very good pinning role at the austenite grain boundary, preventing coarsening of austenite grains. The segregation of B and the addition of Mn result in a significant reduction in both the minimum boron reverse melt content and the final solidification temperature. In the continuous cooling stage, martensitic transformation occurs at the cooling rate of 60 °C/s, and the martensite start point is 400 °C and martensite finish point is 280 °C. A large number of bursts are concentrated from 380 °C to 330 °C. There are two main forms of martensitic transformation: first, martensite begins to appear at the coarse austenite grain boundary, and grows transgranularly. Second, the new martensite laths starts from the previously formed laths and grows at a certain angle into the austenite grains. The main factor in the increase of martensite in continuous cooling is the formation of variable temperature martensite rather than the growth of martensite laths. At the cooling rate of 20 °C/s, the bainite and ferrite transformation appeared and the conversion temperature of bainite was about 600 °C. The cooling speed has a great influence on the performance of the 22MnB5 hot stamping component. The room temperature microhardness at cooling rates of 5 °C/s, 20 °C/s, and 60 °C/s was 194 HV, 243 HV, and 430 HV, respectively. Therefore, ensuring sufficient cooling rate is a key condition for obtaining ultra-high strength hot stamping components.
Halo-independent methods for inelastic dark matter scattering

We present halo-independent methods to analyze the results of dark matter direct detection experiments assuming inelastic scattering. We focus on the annual modulation signal reported by DAMA/LIBRA and present three different halo-independent tests. First, we compare it to the upper limit on the unmodulated rate from XENON100 using (a) the trivial requirement that the amplitude of the annual modulation has to be smaller than the bound on the unmodulated rate, and (b) a bound on the annual modulation amplitude based on an expansion in the Earth's velocity. The third test uses the special predictions of the signal shape for inelastic scattering and allows for an internal consistency check of the data without referring to any astrophysics. We conclude that a strong conflict between DAMA/LIBRA and XENON100 in the framework of spin-independent inelastic scattering can be established independently of the local properties of the dark matter halo.
Solution accelerators for large-scale three-dimensional electromagnetic inverse problems

We provide a framework for preconditioning nonlinear three-dimensional electromagnetic inverse scattering problems using nonlinear conjugate gradient (NLCG) and limited memory (LM) quasi-Newton methods. Key to our approach is the use of an approximate adjoint method that allows for an economical approximation of the Hessian that is updated at each inversion iteration. Using this approximate Hessian as a preconditioner, we show that the preconditioned NLCG iteration converges significantly faster than the non-preconditioned iteration, as well as converging to a data misfit level below that observed for the non-preconditioned method. Similar conclusions are also observed for the LM iteration; preconditioned with the approximate Hessian, the LM iteration converges faster than the non-preconditioned version. At this time, however, we see little difference between the convergence performance of the preconditioned LM scheme and the preconditioned NLCG scheme. A possible reason for this outcome is the behaviour of the line search within the LM iteration. It was anticipated that, near convergence, a step size of one would be approached, but what was observed, instead, were step lengths that were nowhere near one. We provide some insights into the reasons for this behaviour and suggest further research that may improve the performance of the LM methods.
On some physical aspects of isotropic cosmology in Riemann-Cartan spacetime

Isotropic cosmology built in the framework of the Poincaré gauge theory of gravity based on sufficiently general expression of gravitational Lagrangian is considered. The derivation of cosmological equations and equations for torsion functions in the case of the most general homogeneous isotropic models is given. Physical aspects of isotropic cosmology connected with possible solution of dark energy problem and problem of cosmological singularity are discussed.
IoT-Based Smart Environment Monitoring System for Air Pollutant Detection in Kuantan, Pahang, Malaysia

Air pollution is one of the pollutions that release harmful chemicals and if not controlled, it will affect the human respiratory system. Currently, there are two Air Pollution Monitoring system located in Kuantan district to record the pollution’s reading once it detects the air pollutant however, the origin of the pollution cannot be detected by the system. As a solution, a Smart Environment Monitoring System for Air Pollution Using Internet of Things (IoTs) is developed to overcome the weaknesses. This project involved both hardware and software developments, in which hardware development includes the Arduino Uno, Carbon Monoxide (MQ 7), smoke/gas (MQ 135) sensors, a buzzer and LCD display. This system is design so that the current reading can be viewed by admin in a real-time value. Besides, they can also view the data for every 8 hours. These data can be printed in PDF format. In addition, when the reading reached unhealthy value, it will warn the community via its alarm system embedded in this system. However, this system is subject to limitation especially on data delays from sensors to database. As only one existing monitoring system that located at Beserah, thus this new feature will add a sub-sensor that located at the designated area which potentially expose to the air pollution.
A numerical differentiation method and its application to reconstruction of discontinuity

In this paper, we discuss a classical ill-posed problem—numerical differentiation by the Tikhonov regularization. Based on the conditional stability estimate for this ill-posed problem, a new simple method for choosing regularization parameters is proposed. We show that it has an almost optimal convergence rate when the exact solution is in H2. The advantages of our method are (1) we can get similar computational results with much less computation, in comparison with other methods, and (2) we can find the discontinuous points numerically.
Analysis of Double-Stator Switched Flux PM Machines with Non-overlapping Concentrated Windings

Permanent magnet (PM) synchronous machines having double-stator and equipped with non-overlapping concentrated windings, is analyzed in this paper. Thus, there is reduced copper loss, resulting to improved efficiency. Basically, the analyzed machine is a doubly-salient stator-PM machine, with a rotor made of modulating steel ring. The analysis includes the open circuit and on-load characteristics of the developed machines. Furthermore, a quantitative comparison of the electromagnetic analysis of the machines having different winding topology is also detailed in this study. The investigation shows that the even-rotor pole machines are characterized by higher cogging torque as well larger torque ripple, relative to their odd-rotor pole counterparts, due to their high possession of harmonics.
Poisson structure and symmetry in the Chern–Simons formulation of (2 + 1)-dimensional gravity

In the formulation of (2 + 1)-dimensional gravity as a Chern–Simons gauge theory, the phase space is the moduli space of flat Poincaré group connections. Using the combinatorial approach developed by Fock and Rosly, we give an explicit description of the phase space and its Poisson structure for the general case of a genus g oriented surface with punctures representing particles and a boundary playing the role of spatial infinity. We give a physical interpretation and explain how the degrees of freedom associated with each handle and each particle can be decoupled. The symmetry group of the theory combines an action of the mapping class group with asymptotic Poincaré transformations in a nontrivial fashion. We derive the conserved quantities associated with the latter and show that the mapping class group of the surface acts on the phase space via Poisson isomorphisms.
Cosmological constraints on decaying dark matter

We present a complete analysis of the cosmological constraints on decaying dark matter. Previous analyses have used the cosmic microwave background and Type Ia supernova. We have updated them with the latest data as well as extended the analysis with the inclusion of Lyman-α forest, large scale structure and weak lensing observations. Astrophysical constraints are not considered in the present paper. The bounds on the lifetime of decaying dark matter are dominated by either the late-time integrated Sachs-Wolfe effect for the scenario with weak reionization, or CMB polarization observations when there is significant reionization. For the respective scenarios, the lifetimes for decaying dark matter are Γ−1 ≳ 100 Gyr and (fΓ)−1 ≳ 5.3 × 108 Gyr (at 95.4% confidence level), where the phenomenological parameter f is the fraction of the decay energy deposited in baryonic gas. This allows us to constrain particle physics models with dark matter candidates through investigation of dark matter decays into Standard Model particles via effective operators. For decaying dark matter of ∼ 100 GeV mass, we found that the size of the coupling constant in the effective dimension-4 operators responsible for dark matter decay has to generically be ≲ 10−22. We have also explored the implications of our analysis for representative models in theories of gauge-mediated supersymmetry breaking, minimal supergravity and little Higgs.
The warp drive: hyper-fast travel within general relativity

It is shown how, within the framework of general relativity and without the introduction of wormholes, it is possible to modify a spacetime in a way that allows a spaceship to travel with an arbitrarily large speed. By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it, motion faster than the speed of light as seen by observers outside the disturbed region is possible. The resulting distortion is reminiscent of the `warp drive' of science fiction. However, just as happens with wormholes, exotic matter will be needed in order to generate a distortion of spacetime like the one discussed here.