Miracle-dz/UniFAR-FTUs huggingface dataset:
Tensile testing of thin-film microstructures

The mechanical properties of thin film microstructures depend on size and shape and on the film manufacturing process. Hence, the test structures that are used to measure mechanical properties should have dimensions of the same order of magnitude as an application structure. The microstructures are easily monitored in a scanning electron microscope (SEM), but to be handled and tested in situ a micromanipulator was developed. The parts of the micromanipulator essential to the tests are two independently moveable tables driven by electric motors. The test structures and a testing unit are mounted on the tables. A testing unit was designed to measure force and displacement with high resolution. The testing unit consists of an arm actuated by a piezoelectric element and equipped with a probe. An optical encoder measures the movement of the arm, while strain gauges measure the force in the arm. Test structures consist typically of a released beam fixed at one end with a ring at the other. The micromanipulator is used to position the probe of the testing unit in the ring. The testing unit then executed a tensile test of the beam. Test structures of polysilicon films produced under various process conditions were used to verify the possibility of measuring Young's modulus with an accuracy of +/- 5 percent, as well as fracture strength.Young's modulus is calculated using the difference in elongation for different beam lengths. The fracture strength of the beams was evaluated with Weibull statistics.
Relationship between aerodynamic forces, flow structures and wing camber for rotating insect wing planforms

Abstract Wing deformation is observed during the flight of some insect species; however, the effect of these distorted wing shapes on the leading edge vortex (LEV) is not well understood. In this study, we investigate the effect of one of these deformation parameters, (rigid) wing camber, on the flow structures and aerodynamic forces for insect-like wings, using a numerical model of an altered fruit fly wing revolving at a constant angular velocity. Both positive and negative camber was investigated at Reynolds numbers of 120 and 1500, along with the chordwise location of maximum camber. It was found that negatively cambered wings produce very similar LEV structures to non-cambered wings at both Reynolds numbers, but high positive camber resulted in the formation of multiple streamwise vortices at the higher Reynolds number, which disrupt the development of the main LEV. Despite this, positively cambered wings were found to produce higher lift to drag ratios than flat or negatively cambered wings. It was determined that a region of low pressure near the wing’s leading edge, combined with the curvature of the wing’s upper surface in this region, resulted in a vertical tilting of the net force vector for positively cambered wings, which explains how insects can benefit from wing camber.
Graphical Visualisation of the MCNP Mesh Tally File

This paper presents an updated version of the MTV3D (Mesh Tally Visualization in 3D) program with Windows graphical user interface for visualization of the MCNP-based mesh tally files. Several improvements over the previous program version are addressing better figure export functionality ("Save as" option), switching between linear and logarithmic values on axes, dynamic figure scaling in active window, inversion of relative errors from “max” to “min” values, etc. MCNP is a well known and widely used general purpose Monte Carlo computer code for neutron, photon and electron transport simulation through arbitrary three-dimensional configurations. An important feature of the MCNP code is a graphical display of the simulation model using auxiliary program, such as X-window server, which is useful for geometry error-checking during model setup and visualisation of Monte Carlo results from a mesh tally file (i.e. meshtal file) over a structured xyz mesh. Such inspection of the model is useful for the end user, providing an insight of the Monte Carlo convergence process in a phase space and effectiveness of the selected variance reduction parameters in shielding calculations. Basic features and functionalities of the updated MTV3D program are presented on some selected hybrid-shielding problems involving ADVANTG3.0. 3 and MCNP6.1. 1b codes.
Efficient 3D FDTD analysis of arbitrary birefringent and dichroic media with obliquely incident sources

We have developed a 3D Finite Difference Time Domain (FDTD) algorithm to model obliquely incident waves through arbitrary birefringent and dichroic media with transverse periodic boundaries. Beginning with arbitrary conductivity and permittivity tensors, we employed the split-field method (SFM) to enable broadband sources with oblique incidence. We terminate our boundaries with a uniaxial perfectly matched layer (UPML) in one dimension and periodic boundaries in the other two dimensions. The algorithm is validated via several case studies: a polarizer pair, a twisted nematic liquid crystal, and an array of conducting particles. Using this approach, we simulate for the first time polarization gratings with light obliquely incident in directions orthogonal to the grating vector (i.e., at oblique angles outside the normal diffraction plane).
Thermal Effects in a Two-Dimensional Hybrid Elastic Structure

In this paper we consider a two-dimensional hybrid thermo-elastic structure consisting of a thermo-elastic plate which has a beam attached to its free end. We show that the initial-boundary-value problem for the interactive system of partial differential equations which take account of the mechanical strains/stresses and the thermal stresses in the plate and the beam, can be associated with a uniformly bounded evolution operator. It turns out that the interplay of parabolic dynamics due to the thermal effects in the hybrid structure and the hyperbolic dynamics associated with the elasticity of the structure yields analyticity for the entire system. This result yields solvability for the problem under optimal initial freedom of the displacement, velocity, and temperature in the plate and the beam, while uniform stability is readily available.
An Approach to Determining the Unknown Twist/Wrench Subspaces of Lower Mobility Serial Kinematic Chains

Mainly drawing on screw theory and linear algebra, this paper presents an approach to determining the bases of three unknown twist and wrench subspaces of lower mobility serial kinematic chains, an essential step for kinematic and dynamic modeling of both serial and parallel manipulators. By taking the reciprocal product of a wrench on a twist as a linear functional, the underlying relationships among their subspaces are reviewed by means of the dual space and dual basis. Given the basis of a twist subspace of permissions, the causes of nonuniqueness in the bases of the other three subspaces are discussed in some depth. Driven by needs from engineering design, criteria, and a procedure are proposed that enable pragmatic, consistent bases of these subspaces to be determined in a meaningful, visualizable, and effective manner. Three typical examples are given to illustrate the entire process. Then, formulas are presented for the bases of the twist/wrench subspaces of a number of commonly used serial kinematic chains, which can readily be employed for the formulation of the generalized Jacobian of a variety of lower mobility parallel manipulators.
3D FEM analysis of electromagnetic wave scattering from a dielectric sheet in EMC problems

We propose in this paper a new method to study electromagnetic wave scattering by thin sheets for three dimensional problems. The technique takes into account a dielectric sheet of complex permittivity by using a special finite element. The developed procedure is very convenient to implement within an edge element formulation. The theory and formulation of the finite element model is first described. Then, numerical computations are carried out to validate the method.
UIST: an imaging spectrometer for the UK Infrared Telescope

An imaging spectrometer is being designed to take advantage of recent improvements in the image quality achieved at the UK Infrared Telescope. The realization of near-diffraction limited imaging at two microns brings with it the possibility of significant improvements in sensitivity to IR observations. UIST will provide a versatile facility for high spatial resolution imaging and spectroscopy in the 1-5 micrometers wavelength range. We will present the opto-mechanical design of this new instrument, highlighting the innovative features. These include provision of multiple pixel scales within the camera and polarimetry via a Wollaston prism. One of the most challenging areas of the design is the inclusion of a cryogenic integral field unit for area spectroscopy over a 5 inch field. The spectroscopic modes include cross- dispersed spectroscopy over the complete 1-2.5 micrometers wavelength ranges and moderate resolution long slit or area spectroscopy over the complete 1-5 micrometers range. A higher resolution mode will also the included. This will allow USTI to take advantage of the very low backgrounds to be found between OH sky lines. The instruments will incorporate a 1024 X 1024 Indium Antimonide array from SBRC. The development of the IR array controller for UIST will also be discussed.
Function-theoretic degeneracy criteria for Riemannian manifolds.

The modulus of a relatively compact set with border consisting of at least two components is a measure of its magnitude with regard to harmonic functions. A divergent modular sum associated with difference sets obtained from an exhaustion of a Riemannian manifold is characteristic of parabolicity. The existence of a divergent minimum modular sum implies that the manifold carries no nonconstant harmonic functions with finite Dirichlet integral.
The band structures of some transition metal dichalcogenides. II. Group IVA; octahedral coordination

For pt. I see ibid., vol. 5, 738 (1972). The band structures of some group IVA dichalcogenides-ZrS2, ZrSe2, HfS2, HfSe2-are calculated using a semiempirical tight binding method. A symmetry analysis of the crystal structure is given together with the selection rules for optical transitions. The experimental properties of the materials are reviewed and certain features in the optical transmission spectra are used to fix the values of three parameters used in the calculation. The joint density of states function is computed and the results of this and the band structure calculations are discussed.
Ionisation of highly excited atoms by electric fields. II. Classical theory of the Stark effect

For pt.I see ibid., vol.11, no.1, p.37 (1978). The classical adiabatic theory of the Stark ionisation threshold for hydrogenic ions (paper I) is extended to obtain the Stark shifts for all values of the electric field. Exact classical values are calculated and used to find an approximate expression for the energy for all values of the nuclear charge, the parabolic-action integrals and the electric field. Simple quantisation rules are used to obtain a quasiclassical expression for the energy, which is valid for highly excited hydrogenic ions in strong slowly varying electric fields. Comparisons of individual levels with the quantal calculations of Damburg (1976) suggest that the energy expression is accurate to within about 0.2% for all values of the nuclear charge, quantum numbers and electric field, in the absence of relativistic and level-crossing effects.
Caregivers' positive emotion socialization tendencies are associated with positive affect in preschool age children.

Longstanding theories of emotion socialization postulate that caregiver emotional and behavioral reactions to a child's emotions together shape the child's emotion displays over time. Despite the notable importance of positive valence system function, the majority of research on caregiver emotion socialization focuses on negative valence system emotions. In the current project, we leveraged a relatively large cross-sectional study of caregivers (N = 234; 93.59% White) of preschool aged children to investigate whether and to what degree, caregiver (1) emotional experiences, or (2) external behaviors, in the context of preschoolers' positive emotion displays in caregiver-child interactions, are associated with children's general positive affect tendencies. Results indicated that, in the context of everyday caregiver-child interactions, caregiver-reported positively valenced emotions but not approach behaviors were positively associated with child general positive affect tendencies. However, when examining specific caregiver behaviors in response to everyday child positive emotion displays, caregiver report of narrating the child's emotion and joining in the emotion with their child was positively associated with child general positive affect tendencies. Together, these results suggest that in everyday caregiver-child interactions, caregivers' emotional experiences and attunement with the child play a role in shaping preschoolers' overall tendencies toward positive affect.
Inequities in Mental Health Care Facing Racialized Immigrant Older Adults With Mental Disorders Despite Universal Coverage: A Population-Based Study in Canada

Abstract Objectives Contemporary immigration scholarship has typically treated immigrants with diverse racial backgrounds as a monolithic population. Knowledge gaps remain in understanding how racial and nativity inequities in mental health care intersect and unfold in midlife and old age. This study aims to examine the joint impact of race, migration, and old age in shaping mental health treatment. Methods Pooled data were obtained from the Canadian Community Health Survey (2015–2018) and restricted to respondents (aged ≥45 years) with mood or anxiety disorders (n = 9,099). Multivariable logistic regression was performed to estimate associations between race–migration nexus and past-year mental health consultations (MHC). Classification and regression tree (CART) analysis was applied to identify intersecting determinants of MHC. Results Compared to Canadian-born Whites, racialized immigrants had greater mental health needs: poor/fair self-rated mental health (odds ratio [OR] = 2.23, 99% confidence interval [CI]: 1.67–2.99), perceived life stressful (OR = 1.49, 99% CI: 1.14–1.95), psychiatric comorbidity (OR = 1.42, 99% CI: 1.06–1.89), and unmet needs for care (OR = 2.02, 99% CI: 1.36–3.02); in sharp contrast, they were less likely to access mental health services across most indicators: overall past-year MHC (OR = 0.54, 99% CI: 0.41–0.71) and consultations with family doctors (OR = 0.67, 99% CI: 0.50–0.89), psychologists (OR = 0.54, 99% CI: 0.33–0.87), and social workers (OR = 0.37, 99% CI: 0.21–0.65), with the exception of psychiatrist visits (p = .324). The CART algorithm identifies three groups at risk of MHC service underuse: racialized immigrants aged ≥55 years, immigrants without high school diplomas, and linguistic minorities who were home renters. Discussion To safeguard health care equity for medically underserved communities in Canada, multisectoral efforts need to guarantee culturally responsive mental health care, multilingual services, and affordable housing for racialized immigrant older adults with mental disorders.
Flow Simulations in a Sub-Micro Porous Medium by the Lattice Boltzmann and the Molecular Dynamics Methods

In order to devise and establish a cost-effective strategy to simulate flows in continuum to slip and transitional regimes, present study focuses on evaluating a lattice Boltzmann equation [Niu et al., Phys. Rev. E 76, 036711, 2007] formerly proposed by the present authors’ group. The main test flow case is a flow around a square cylinder situated in a sub-micro channel. Since a rather shorter streamwise domain size and a periodic streamwise boundary condition are imposed, the flow regime is regarded as a part of an infinite cylinder array set in a narrow channel which can be considered as a kind of micro-porous media. For the assessment of the lattice Boltzmann simulations, the molecular dynamics (MD) simulations using Leonard-Jones potential are also performed. In the MD simulations, novel boundary treatments are applied. The results of the square cylinder flow by both the simulations at Knudsen number Kn=0.08 show reasonable agreement and confirm the reliability of the present lattice Boltzmann method (LBM). The fact that the computational time of the present MD simulation to obtain the reliable statistics is 1800 times as much as that of the LBM clearly indicates the usability of the LBM for engineering applications even in the slip and transitional flow regimes.Copyright © 2009 by ASME
Q-ball-like solitons on the M2-brane with worldvolume fluxes

In this paper we obtain a family of analytic solutions to the nonlinear partial differential equations that describe the dynamics of the bosonic part of the mass operator of a M2-brane compactified on $M_9\times T^2$ in the LCG with worldvolume fluxes. Those fluxes can be induced by a constant and quantized supergravity 3-form. This sector of the theory, at supersymmetric level, has the interesting property of having a discrete spectrum. We have focused on the characterization of Q-ball-like (QBL) solitons on the M2-brane with worldvolume fluxes. Two scenarios are analysed: one in which the system is isotropic and the other anisotropic. In the isotropic case, we obtain analytic families of string-like solutions to the membrane equations of motion in the presence of a non-vanishing symplectic gauge field that satisfy all constraints. We explicitly show a localised family of QBL solutions. It is demonstrated that although the solutions generally exhibit dispersion, they also allow for dispersion-free solutions. In the non-isotropic case, we obtain full-fledged membrane QBL solutions by numerical methods. We characterize some other properties of the solutions found. The dynamics of the QBL solutions are also encountered. We analyze the Lorentz boosts and Galilean transformations. Since we work in the Light Cone Gauge, the Lorentz transformed solutions are not automatically solutions, rather some extra conditions must be imposed. Only a subset of the solutions remain. We discuss some examples. The QBL solitons of the M2-brane that have been discovered contain an interaction term between the Noether charge of the Q-ball and the topological monopole charge associated with the worldvolume flux. The monopole charge increases the stability of the analytic solutions against fission.
Reliability-Oriented Resource Allocation for Wireless Powered Short Packet Communications With Multiple WPT Sources

We study a multi-source wireless power transfer (WPT) enabled network supporting multi-sensor transmissions. Activated by the energy harvesting from multiple WPT sources, the sensors transmit short packets to a destination with finite blocklength (FBL) codes. This work for the first time characterizes the FBL reliability for such multi-source WPT enabled network and accordingly provides reliability-oriented resource allocation designs, while a practical nonlinear EH model (including the effects of mutual interference among multiple RF signals) is considered. For the scenario with a fixed frame structure, we aim to maximize the FBL reliability via optimally allocating the transmit power among the multiple WPT sources. In particular, we investigate the relationship between the overall error probability and the transmit power of multiple WPT sources, based on which a power allocation problem is formulated. To solve the formulated non-convex problem, we first introduce auxiliary variables to make the problem analytically tractable, based on which an iterative algorithm is proposed while applying successive convex approximation (SCA) technique to the non-convex components of the problem. Then, we extend our design into a dynamic frame structure scenario, i.e., the blocklength allocated for WPT phase and short-packet transmission phase are adjustable, which introduces more flexibility and new challenges. In particular, we provide a joint power and blocklength allocation design maximizing the overall reliability under total power and blocklength constraints. A problem with high-dimension variables is formulated, which suffers from the complex and non-convex relationship among system reliability, multiple source power and blocklength. To tackle the difficulties, auxiliary variables introduction, multiple variable substitutions along with SCA technique utilization are exploited to reformulate and efficiently solve the problem. Finally, through numerical results, we validate our analytical model and evaluate the system performance, where a set of guidelines for practical system design are concluded.
PipeLearn: Pipeline Parallelism for Collaborative Machine Learning

Collaborative machine learning (CML) techniques, such as federated learning, were proposed to collaboratively train deep learning models using multiple end-user devices and a server. CML techniques preserve the privacy of end-users as it does not require user data to be transferred to the server. Instead, local models are trained and shared with the server. However, the low resource utilisation of CML techniques makes the training process inefficient, thereby limiting the use of CML in the real world. Idling resources both on the server and devices due to sequential computation and communication is the principal cause of low resource utilisation. A novel framework PipeLearn that leverages pipeline parallelism for CML techniques is developed to improve resource utilisation substantially. A new training pipeline is designed to parallelise the computations on different hardware resources and communication on different bandwidth resources, thereby accelerating the training process in CML. The pipeline is further optimised to ensure maximum utilisation of available resources. The experimental results confirm the validity of the underlying approach of PipeLearn and highlight that when compared to federated learning: (i) the idle time of the server can be reduced by 2.2x - 28.5x, (ii) the network throughput can be increased by 56.6x - 321.3x, and (iii) the overall training time can be accelerated by 1.5x - 21.6x under varying network conditions for two popular convolutional models without sacrificing accuracy. PipeLearn is available for public download from https://github.com/blessonvar/PipeLearn.
Evaluation of Legged Robot Landing Capability Under Aggressive Linear and Angular Velocities

This paper proposes a method to evaluate the capability of aggressive legged robot landing under significant touchdown linear and angular velocities upon impact. Our approach builds upon the Planar Inverted Pendulum with Flywheel (PIPF) model and introduces a landing framework for the first stance step on a non-dimensional basis. We develop a nonlinear framework with iterative constrained trajectory optimization to stabilize the first stance step prior to N-step Capturability analysis. Performance maps across many different initial conditions reveal approximately linear boundaries as well as the effect of inertia, body incidence angle and leg attacking angle on the boundary shape. Our method also yields the engineering insight that body inertia affects the performance map the most, hence its optimization can be prioritized when the target is to improve robot landing efficacy.