Investigation of Inside-Out Tracking Methods for Six Degrees of Freedom Pose Estimation of a Smartphone in Augmented Reality

Six degrees of freedom(6DoF)input interfaces are essential formanipulating virtual objects through translation or rotation in three-dimensional(3D)space.A traditional outside-in tracking controller requires the installation of expensive hardware in advance.While inside-out tracking controllers have been proposed,they often suffer from limitations such as interaction limited to the tracking range of the sensor(e.g.,a sensor on the head-mounted display(HMD))or the need for pose value modification to function as an input interface(e.g.,a sensor on the controller).This study investigates 6DoF pose estimation methods without restricting the tracking range,using a smartphone as a controller in augmented reality(AR)environments.Our approach involves proposing methods for estimating the initial pose of the controller and correcting the pose using an inside-out tracking approach.In addition,seven pose estimation algorithms were presented as candidates depending on the tracking range of the device sensor,the tracking method(e.g.,marker recognition,visual-inertial odometry(VIO)),and whether modification of the initial pose is necessary.Through two experiments(discrete and continuous data),the performance of the algorithms was evaluated.The results demonstrate enhanced final pose accuracy achieved by correcting the initial pose.Furthermore,the importance of selecting the tracking algorithm based on the tracking range of the devices and the actual input value of the 3D interaction was emphasized.

Hydrogen Permeation Characteristics of Pd-CuMembrane in Plasma Membrane Reactor

Hydrogen is an alternative energy source that has the potential to replace fossil fuels.One of the hydrogen applications is as a material for Polymer Electrolyte Membrane Fuel Cells(PEMFC)in fuel cell vehicles.High-purity hydrogen can be obtained using a hydrogen separation membrane to prevent unwanted contaminants from potentially harming the PEMFC components.In this study,we fabricated a plasma membrane reactor and investigated the permeation performance of a hydrogen separation membrane in a plasma membrane reactor utilizing atmospheric pressure plasma.The result showed the hydrogen permeation rate increasing with time as reactor temperature is increased through joule heating.By decreasing the gap length of the reactor from 2 to 1 mm,the hydrogen permeation rate increases by up to 40%.The hydrogen permeation rate increases by 30%when pressure is applied to the plasma membrane reactor by up to 100 kPa.

Fate and Behavior of Tetracycline Resistance Genes in Activated Carbon Adsorption

The accessibility of tetracycline resistance gene (tetG) into the pores of activated carbon (AC), as well as the impact of the pore size distribution (PSD) of AC on the uptake capacity of tetG, were investigated using eight types of AC (four coal-based and four wood-based). AC showed the capability to admit tetG and the average reduction of tetG for coal-based and wood-based ACs at the AC dose of 1 g·L-1 was 3.12 log and 3.65 log, respectively. The uptake kinetic analysis showed that the uptake of the gene followed the pseudo-second-order kinetics reaction, and the uptake rate constant for the coal-based and wood-based ACs was in the range of 5.97 × 10-12 - 4.64 × 10-9 and 7.02 × 10-11 - 1.59 × 10-8 copies·mg-1·min-1, respectively. The uptake capacity analysis by fitting the obtained experiment data with the Freundlich isotherm model indicated that the uptake constant (KF) values were 1.71 × 103 - 8.00 × 109 (copies·g-1)1-1/n for coal-based ACs and 7.00 × 108 - 3.00 × 1010 (copies·g-1)1-1/n for wood-based ones. In addition, the correlation analysis between KF values and pore volume as well as pore surface at different pore size regions of ACs showed that relatively higher positive correlation was found for pores of 50 - 100 Å, suggesting ACs with more pores in this size region can uptake more tetG. The findings of this study are valuable as reference for optimizing the adsorption process regarding antibiotic resistance-related concerns in drinking water treatment.

Fundamental Study on Response Properties of Structures Constructed on Lunar Regolith

The Artemis Program, for constructing the lunar base, is in progress. How to design and construct architectural and civil engineering structures in the lunar environment has become an important issue. The lunar surface is covered with soft sand, called regolith, and it is required to protect lunar bases and structures, as well as internal precision equipment, against vibrational disturbances such as moonquakes and meteorite collisions. Therefore, in this study, the static and cyclic triaxial compression tests of the regolith simulant were conducted. The reference strain and equivalent damping factor of the regolith simulant were smaller compared to sandy soil on Earth. In addition, a shaking table test using model specimens was conducted on the response properties of regolith ground alone and structures set on regolith ground. The buried foundation and pile foundation notably suppressed the horizontal response attributed to the rocking component compared to a direct foundation.

Improvement of Intergranular Stress Corrosion Crack Susceptibility of Austenite Stainless Steel through Grain Boundary Engineering

Intergranular stress corrosion crack susceptibility of austenite stainless steel was evaluated through threepoint bending test conducted in high temperature water. The experimental results showed that the frequent and efficient introduction of low energy coincidence site lattice boundaries through grain boundary engineering resulted in an apparent improvement of the intergranular stress corrosion crack resistance of austenite stainless steel.

Research progress and prospect of interaction between rock engineering and geo-environments

In recent years, a large number of geotechnical engineering projectshave been completed or under construction in China, such asthe Three Gorges Dam Project, Expressway Network Plan, South-to-North Water Diversion Project, West-to-East Gas Pipeline Project,etc. （Wang, 2003; Li, 2010; Huang, 2011; She and Lin, 2014）. Theconstruction of large-scale geotechnical engineering not onlybrings huge economic benefits, but also causes large interferenceto the lithosphere and hydrosphere that we rely on for survival（Wang et al., 2005）. This paper focuses on the interaction mechanismof rock engineering and geo-environments in the fields of urbanunderground space utilization, natural gas hydrate exploitationand high-level radioactive waste disposal.

Decarbonization options of the iron and steelmaking industry based on a three-dimensional analysis

Decarbonization is a critical issue for peaking CO_(2) emissions of energy-intensive industries,such as the iron and steel industry.The decarbonization options of China’s ironmaking and steelmaking sector were discussed based on a systematic three-dimensional low-carbon analysis from the aspects of resource utilization(Y),energy utilization(Q),and energy cleanliness which is evaluated by a process general emission factor(PGEF)on all the related processes,including the current blast furnace(BF)-basic oxygen furnace(BOF)integrated process and the specific sub-processes,as well as the electric arc furnace(EAF)process,typical direct reduction(DR)process,and smelting reduction(SR)process.The study indicates that the three-dimensional aspects,particularly the energy structure,should be comprehensively considered to quantitatively evaluate the decarbonization road map based on novel technologies or processes.Promoting scrap utilization(improvement of Y)and the substitution of carbon-based energy(improvement of PGEF)in particular is critical.In terms of process scale,promoting the development of the scrap-based EAF or DR-EAF process is highly encouraged because of their lower PGEF.The three-dimensional method is expected to extend to other processes or industries,such as the cement production and thermal electricity generation industries.

Strength and deformation behavior of the Yellow River silt under triaxial drained condition considering characteristic states

Currently,the application of the Yellow River silt in subgrade,especially in expressway subgrade,has not been widely promoted.The main reason is that the research on the mechanical characteristics of the Yellow River silt used for subgrade filling is extremely limited.In this study,the static shear test of the Yellow River silt under drained condition was carried out using Global Digital Systems(GDS)triaxial apparatus,and the effects of confining pressure,relative density and shear rate on the strength and deformation behavior of the Yellow River silt were investigated.The cohesive force of the Yellow River silt is low,and the friction angle is the main factor determining the shear strength.Friction angle at phase transformation stateφpt,friction angle at peak stateφps,friction angle at critical stateφcs,were obtained via the observation on the evolution law of mobilized friction angle during the whole shearing process.The friction angles corresponding to three different characteristic states have the following magnitude relationship,namelyφps>φcs>φpt.The strength parameters for low-grade subgrade and highgrade subgrade were chosen to be 29.33°and 33.75°.The critical state line(CSL),envelop of phase transformation(EOP),and envelop of dilatancy(EOD)for three different characteristic states were determined.The critical stress ratio M,the phase transformation stress ratio Mptand the dilatancy stress ratio Mdof the Yellow River silt are 1.199,1.235,1.152,respectively.These results provide a basis for the mechanical analysis of the Yellow River silt subgrades and the subsequent establishment of dynamic constitutive model of the Yellow River silt.

Fabrication of a model specimen for understanding micro-galvanic corrosion at the boundary ofα-Mg andβ-Mg17Al12

A model specimen with a single boundary of theα/βphase simulating Mg-Al alloys was successfully fabricated by spark plasma sintering.A small electrode area ofαphase orβphase was prepared using the model specimen,and the OCPs(open-circuit potentials)of each phase and a small electrode area containing theα/βphase boundary in 0.1 M NaCl at pH 8.0 were compared:theβphase exhibited a higher potential,and theαphase showed a lower potential.The OCP of the small area containing theα/βphase boundary was the intermediate value of these phases.In a small area containingα/βphase boundary,discoloration and gas bubbles were observed on theαphase,but no bubble generation was detected on theβphase.The gas bubbles were initially generated on theαphase near theβphase,but as the discoloration(corrosion)of theαphase approached theβphase,the bubbles were generated on theβphase.In micro-galvanic corrosion of theαandβphases,theβphase did not always function as the preferred cathode.Theαphase partially corroded(or discolored)and became the anodes,so that the surrounding areas were most likely to be the cathodes.When corroded areas(anodes)in theαphase approached theβphase,theβphase would become cathodes.In addition to the micro-galvanic corrosion mechanism,the role of Al in corrosion resistance at theα/βphase boundary was determined by surface analysis.

Artificial neural network-based determination of denoised optical properties in double integrating spheres measurement

Accurate determination of the optical properties of biological tissues enables quantitative understanding of light propagation in these tissues for optical diagnosis and treatment applications.The absorption(μa)and scattering(μs)coe±cients of biological tissues are inversely analyzed from their diffuse re°ectance(R)and total transmittance(T),which are measured using a double integrating spheres(DIS)system.The inversion algorithms,for example,inverse adding doubling method and inverse Monte Carlo method,are sensitive to noise signals during the DIS measurements,resulting in reduced accuracy during determination.In this study,we propose an arti ficial neural network(ANN)to estimateμa andμs at a target wavelength from the R and T spectra measured via the DIS to reduce noise in the optical properties.Approximate models of the optical properties and Monte Carlo calculations that simulated the DIS measurements were used to generate spectral datasets comprisingμa,μs,R and T.Measurement noise signals were added to R and T,and the ANN model was then trained using the noise-added datasets.Numerical results showed that the trained ANN model reduced the effects of noise inμa andμs estimation.Experimental veri fication indicated noise-reduced estimation from the R and T values measured by the DIS with a small number of scans on average,resulting in measurement time reduction.The results demonstrated the noise robustness of the proposed ANN-based method for optical properties determination and will contribute to shorter DIS measurement times,thus reducing changes in the optical properties due to desiccation of the samples.

Surface manipulation of a triple-conducting cathode for protonic ceramic fuel cells to enhance oxygen reduction activity and CO_(2) tolerance

One of the main obstacles limiting the performance of protonic ceramic fuel cells(PCFCs) is the sluggish kinetics of the oxygen reduction reaction(ORR) at reduced temperatures.Here,the surface manipulation of a triple-conducting cathode BaCe_(0.5)Pr_(0.3)Y_(0.2)O_(3-δ)(BCPY) by an efficient catalyst coating PrNi_(0.5)Co_(0.5)O_(3-δ)(PNC) to enhance the ORR activity and CO_(2) tolerance is reported.The developed PNC-coated BCPY cathode achieves the polarization resistance of 0.25 and 1.00 Ω cm^(2) at 600 and 500 ℃,respectively,approximately 1/5 of that for the pristine BCPY cathode(0.99 and 4.79 Ω cm^(2)),while maintaining an excellent CO_(2) tolerance.The single cell on a BaZr_(0.8)Yb_(0.2)O_(3-δ) electrolyte also exhibits a high peak power density of 0.79 W cm^(-2)at 700 ℃ and a stable operation for 200 h at 600 ℃.Such high ORR activity is mainly attributed to the synergistic effect of BCPY support and PNC nanoparticles.Namely,BCPY provides a tripleconducting path(mainly protons),and PNC nanoparticles facilitates surface oxygen exchange and steam adsorption/desorption processes due to the enriched surface oxygen vacancies.This study will provide a new design strategy for developing high-performance PCFCs cathode.

Initial testing of ohmic heating through double flux swing during electron cyclotron start-up in the QUEST spherical tokamak

A power-supply system was developed for Ohmic heating(OH)to double×10^(18)the amount of change magnetic flux in the primary central solenoid(CS)on the QUEST spherical tokamak.Two power supplies are connected with stacks of insulated-gate bipolar transistors,and sequentially operated to generate positive and negative CS currents.This bipolar power-supply system is controlled via a field-programmable gate array,which guarantees the safety of the entire system operation.The new OH system,assisted by electron cyclotron heating,enables the stable generation of plasma currents exceeding 100 k A.Moreover,the achieved electron density over the wide range in the major radial direction exceeds the cut-off density for one of the highpower microwave sources in QUEST.This strategy yields target plasmas for future experiments with the electron Bernstein wave.

Hardening effect and precipitation evolution of an isothermal aged Mg-Sm based alloy

The age-hardening behavior and precipitation evolution of an isothermal aged Mg-5Sm-0.6Zn-0.5Zr(wt.%) alloy have been systematically investigated by means of transmission electron microscopy(TEM) and atomic-resolution high-angle annular dark field scanning transmission electron microscopy(HAADF-STEM). The Vickers hardness of the present alloy increases first and then decreases with ageing time. The sample aged at 200 ℃ for 10 h exhibits a peak-hardness of 90.5 HV. In addition to the dominant β_(0)’ precipitate(orthorhombic,a = 0.642 nm, b = 3.336 nm and c = 0.521 nm) formed on {11-20}α planes, a certain number of γ’’ precipitate(hexagonal, a = 0.556 nm and c = 0.431 nm) formed on basal planes are also observed in the peak-aged alloy. Significantly, the basal γ’’ precipitate is more thermostable than prismatic β_(0)’ precipitate in the present alloy. β_(0)’ precipitates gradually coarsened and were even likely to transform into β_(1) phase(face centered cubic, a = 0.73 nm) with the increase of ageing time, which accordingly led to a gradual decrease in number density of precipitates and finally resulted in the decreased hardness and mechanical property in the over-aged alloys.

Effect of hydrogen peroxide on selective flotation of chalcocite and enargite

Enargite is typically associated with chalcocite.Owing to the similarity in the flotation behaviors of these minerals,both minerals are reported to concentrate in the conventional flotation circuit.However,inorganic arsenic in enargite can decrease the copper concentrate quality and increase the operating cost of processing this concentrate.Separating these minerals is important for cleaner copper production to avoid these effects.In this context,this study investigated the effect of hydrogen peroxide(H_(2)O_(2))treatment on the flotation behavior of chalcocite and enargite.Flotation tests of pure and mixed minerals indicated that H_(2)O_(2)treatment reduced the floatability of chalcocite and enargite by forming sulfate and copper hydroxide on their surfaces.Despite the detrimental effect of the H_(2)O_(2)treatment,there was a narrow window of H_(2)O_(2)concentration for separating both minerals,in which enargite floated and chalcocite was depressed.This selective flotation behavior was caused by the rapid adsorption of potassium amyl xanthate(KAX)and lower surface oxidation of enargite compared with that of chalcocite.

Rapid growth of nanostructure on tungsten thin film by exposure to helium plasma

A fiberform nanostructure was synthesized by exposing high-density helium plasma to a 100 nm thick tungsten thin film in the linear plasma device NAGDIS-II.After helium plasma exposure,the cross-section of samples was observed by a scanning electron microscope,transmission electron microscope,and focused ion beam scanning electron microscope.It is shown that the thickness of the nanostructured layer increases significantly for only a short irradiation time.The optical absorptivity remains high,even though it is exposed to helium plasma for a short time.The usage of the thin film can shorten the processing time for nanostructure growth,which will be beneficial for commercial production.

Numerical Analysis on Temperature Distribution in a Single Cell of PEFC Operated at Higher Temperature by1D Heat Transfer Model and 3D Multi-Physics Simulation Model

This study is to understand the impact of operating conditions, especially initial operation temperature (Tini) which is set in a high temperature range, on the temperature profile of the interface between the polymer electrolyte membrane (PEM) and the catalyst layer at the cathode (i.e., the reaction surface) in a single cell of polymer electrolyte fuel cell (PEFC). A 1D multi-plate heat transfer model based on the temperature data of the separator measured using the thermograph in a power generation experiment was developed to evaluate the reaction surface temperature (Treact). In addition, to validate the proposed heat transfer model, Treact obtained from the model was compared with that from the 3D numerical simulation using CFD software COMSOL Multiphysics which solves the continuity equation, Brinkman equation, Maxwell-Stefan equation, Butler-Volmer equation as well as heat transfer equation. As a result, the temperature gap between the results obtained by 1D heat transfer model and those obtained by 3D numerical simulation is below approximately 0.5 K. The simulation results show the change in the molar concentration of O2 and H2O from the inlet to the outlet is more even with the increase in Tini due to the lower performance of O2 reduction reaction. The change in the current density from the inlet to the outlet is more even with the increase in Tini and the value of current density is smaller with the increase in Tini due to the increase in ohmic over-potential and concentration over-potential. It is revealed that the change in Treact from the inlet to the outlet is more even with the increase in Tini irrespective of heat transfer model. This is because the generated heat from the power generation is lower with the increase in Tini due to the lower performance of O2 reduction reaction.

Twin-twin geometric structure effect on the twinning behavior of an Mg-4Y-3Nd-2Sm-0.5Zr alloy traced by quasi-in-situ EBSD

We studied the microstructure evolution of Mg-4Y-3Nd-2Sm-0.5Zr alloy by quasi-in-situ electron backscatter diffraction(EBSD)along with several strains under compression tests,which provided direct evidence for the influence of different twin-twin geometric structure on the twinning behavior.The results showed that the mechanical properties of the alloy were higher than traditional magnesium alloys(the maximum compressive strength reaches 402.5 MPa)due to the strengthening effect of Sm and Nd elements addition on solution strengthening,precipitation strengthening,and grain refinement.Combined with the quasi-in-situ EBSD technique,two different twin-twin geometric structures,‘parallel structure’and‘cross structure’,were observed directly in the alloy.In the later stage of deformation,for‘parallel structure’,residual stress and a large number of dislocations mainly existed in the twin boundary and tip position.For the‘cross structure’,there was a lot of dislocation density in the interior of twins after fusion.The twin growth rate of‘parallel structure’was much faster than that of‘cross structure’because the stress of twins was mainly concentrated on the tip of twin.When the movement for the tip of twin was blocked,the growth rate of twin would be obviously decreased.Moreover,the‘cross structure’was easy to produce closed space.Due to the constraints of surrounding twins,the confined space was easy to stress concentration,thus inhibiting the growth of twins.At the same time,the‘cross structure’of twins needed a more external force to continue to deform,which also served as a strengthening structure.

Phylobone: a comprehensive database of bone extracellular matrix proteins in human and model organisms

The bone extracellular matrix(ECM) contains minerals deposited on highly crosslinked collagen fibrils and hundreds of noncollagenous proteins. Some of these proteins are key to the regulation of bone formation and regeneration via signaling pathways,and play important regulatory and structural roles. However, the complete list of bone extracellular matrix proteins, their roles, and the extent of individual and cross-species variations have not been fully captured in both humans and model organisms. Here, we introduce the most comprehensive resource of bone extracellular matrix(ECM) proteins that can be used in research fields such as bone regeneration, osteoporosis, and mechanobiology. The Phylobone database(available at https://phylobone.com) includes 255proteins potentially expressed in the bone extracellular matrix(ECM) of humans and 30 species of vertebrates. A bioinformatics pipeline was used to identify the evolutionary relationships of bone ECM proteins. The analysis facilitated the identification of potential model organisms to study the molecular mechanisms of bone regeneration. A network analysis showed high connectivity of bone ECM proteins. A total of 214 functional protein domains were identified, including collagen and the domains involved in bone formation and resorption. Information from public drug repositories was used to identify potential repurposing of existing drugs. The Phylobone database provides a platform to study bone regeneration and osteoporosis in light of(biological) evolution,and will substantially contribute to the identification of molecular mechanisms and drug targets.

Induction heating for desorption of surface contamination for high-repetition laser-driven carbon-ion acceleration

This study reports the first experimental demonstration of surface contamination cleaning from a high-repetition supply of thin-tape targets for laser-driven carbon-ion acceleration.The adsorption of contaminants containing protons,mainly water vapor and hydrocarbons,on the surface of materials exposed to low vacuum(>10^(−3)Pa)suppresses carbon-ion acceleration.The newly developed contamination cleaner heats a 5-μm-thick nickel tape to over 400℃in 100 ms by induction heating.In the future,this heating method could be scaled to laserdriven carbon-ion acceleration at rates beyond 10 Hz.The contaminant hydrogen is eliminated from the heated nickel surface,and a carbon source layer—derived from the contaminant carbon—is spontaneously formed by the catalytic effect of nickel.The species of ions accelerated from the nickel film heated to various temperatures have been observed experimentally.When the nickel film is heated beyond∼150℃,the proton signal considerably decreases,with a remarkable increase in the number and energy of carbon ions.The Langmuir adsorption model adequately explains the temperature dependence of desorption and re-adsorption of the adsorbed molecules on a heated target surface,and the temperature required for proton-free carbon-ion acceleration can be estimated.

Effects of sawtooth heat pulses on edge flows and turbulence in a tokamak plasma

Enhancements of edge zonal flows,radial electric fields,and turbulence are observed in electron cyclotron resonance heating-heated plasmas(Zhao et al 2013 Nucl.Fusion 53083011).In this paper,the effects of sawtooth heat pulses on flows and turbulence are presented.These experiments are performed using multiple Langmuir probe arrays in the edge plasmas of the HL-2A tokamak.The edge zonal flows,radial electric fields,and turbulence are all enhanced by sawteeth.Propagation of the zonal flow and turbulence intensities is also observed.The delay time of the maximal intensity of the electric fields,zonal flows,and turbulence with respect to the sawtooth crashes is estimated as~1 ms and comparable to that of the sawtooth-triggered intermediate phases.Not only the zonal flows but also the radial electric fields lag behind the turbulence.Furthermore,the intensities of both the zonal flows and electric fields nearly linearly increase/decrease with the increase/decrease of the turbulence intensity.A double-source predator-prey model analysis suggests that a relatively strong turbulence source may contribute to the dominant zonal flow formation during sawtooth cycles.