Ar System Research Articles

Augmented Reality-assisted Pedicle Instrumentation: Versatility Across Major Instrumentation Sets.

Laboratory investigation with phantom spine models. The aim of this study was to demonstrate the ability of Augmented Reality system to track instruments from different companies without major modifications. Augmented Reality is an emergent technology with applications in industrial, military, gaming, and medical fields. AR applications in Spine surgery are actively being developed. Features of headpiece ergonomics, digital processing power, intuitive interface, and reliable accuracy are being optimized for successful adaptation of technology into the field. System versatility across various instrumentation sets is important for cost-effectiveness and efficiency in application. In this project, five phantom spine models were instrumented L1-S1 with pedicle screws from five major companies. AR assistance was used for all. Each screwdriver was equipped with a generic 3D printed navigation marker for tracking. Every instrumentation set was successfully paired with AR navigation imaging. Sixty pedicle screws were inserted with an average time of 1.6 min/screw. There was an evidence of learning curve with fastest time achieved of 1 min/screw. All five systems had equivocal radiographic outcomes. There were two breached screws (3%). Any currently available instrumentation set can readily pair for tracking with Augmented Reality system. Active tracking of the drivers allowed for improved accuracy making AR system very attractive as an adjunct to the current instrumentation techniques. 3.

The noble gases in five ordinary chondrites from Grove Mountains in Antarctica

Here we present the abundances and isotopic compositions of the noble gases He, Ne, Ar, Kr, and Xe in five bulk ordinary chondrites from Antarctica, namely Grove Mountains (GRV)054472, GRV053690, GRV022403, GRV023149, and GRV052243. The cosmic ray exposure (CRE) ages of the three H chondrites GRV054472 (H3), GRV053690 (H4), and GRV022403 (H4) are 3.8 ​± ​0.3 ​Ma, 5.9 ​± ​0.4 ​Ma, and 16.6 ​± ​1.5 ​Ma, respectively. This finding is consistent with peaks in the exposure age histogram for H chondrites at 4 ​Ma and 7.2 ​Ma, respectively and also with the broad age cluster at 15–20 ​Ma, which is especially pronounced for H4 chondrites. The two L6 chondrites GRV023149 and GRV052243 are most likely paired with consistent exposure ages of 17.4 ​± ​1.1 ​Ma and 17.6 ​± ​1.5 ​Ma that both fall into the peak at 15 ​Ma for L6 chondrites. The two meteorites GRV054472 and GRV053690 show significant 3He or 3H diffusive losses of about 10% and 20–30%, respectively. The 4He gas retention ages for the three H chondrites are in the range 1.09–3.18 ​Ga, showing different degrees of degassing either at a thermal event on the parent body or during cosmic ray exposure after the ejection from the parent body. The low gas retention ages for the two L6 chondrites based on (U–Th)/He systematics are 259 ​Ma (mean age of two aliquots) and 320 ​Ma or 364 ​Ma (mean age of two aliquots) and 307 ​Ma based on K–Ar system. These ages indicate significant gas loss during the catastrophic break-up of the L-chondrite parent body. Trapped Kr in GRV054472 and GRV053690-2 is almost pure Kr-Q. In addition, other meteorites also contain Q as trapped Kr, but have discernable cosmogenic Kr. The excess 82Kr observed in GRV052243 and GRV022403 is due to the neutron capture on 81Br. Radiogenic 129Xe∗ from the decay of 129I was observed in all studied chondrites. Measured Xe isotopes in all the studied chondrites predominantly shows Q component with minor contributions from the terrestrial atmosphere. For the samples GRV053690-2 and GRV023149-2, measured Xe falls on a mixing line with Xe-SW and Xe-HL, although the later component contributes very little.

Augmented Reality for Dies Alignment in Machine Setup

Forging is one of the material deformation processing techniques. While the operation cycle is short and efficient, the machine setup process is generally long and time consuming. One of the difficulties in operation is position alignment procedure of the equipment during the die changing process. Due to the size and shape complexity of the machine and equipment, the operators are not able to clearly see the important parts – e.g. guided pins, holes, and sub-plate which need to be moved to finely adjust the alignment. Augmented Reality (henceforth AR) is used to solve this problem by rendering virtual objects and guides associated to those parts over the real equipment. Thus, the operators can monitor the position of the parts during the alignment process through the virtual objects. This AR system is developed based on ARcore SDK together with Unity on the Android platform. The experiment was conducted in real factory environment.

Generalized CVD Diagram of the Si–C–N–H–Не(Ar) System

Silicon carbonitride (SiCxNy) films have useful properties and thereby wide potential for practical use. Methods for the preparation of bulk and film SiCxNy-based materials are intensively developing. Here, we consider the preparation of such films by chemical vapor deposition (CVD) using organosilicon compounds as precursors. Additional components of the input gases are NH3 and N2 as reagents and an inert gas (He or Ar). The principles of thermodynamic calculations of the CVD process occurring under quasi-equilibrium conditions are analyzed. A generalized CVD diagram for the Si–C–N–H–He(Ar) system having excessive carbon has been designed in the area of deposition parameters where p = 0.01–10 Torr, T = 600–1400 K, and n(N)/n(Si) = 1–10. This diagram will be useful in experimental studies of the Si–C–N–H–He(Ar) system.

Augmented Reality Technologies for Interior Design Planning using a Simultaneous Localization and Mapping Method

Planning the placement of furniture in a room is an important planning process, with proper planning, the placement of furniture can be more efficient in the use of space, as well as from an aesthetic point of view. During this time the process can be done by using a sketch or other manual method. In this research, we use augmented reality technology to plan furniture placement in a room. We use the Markerless technique in the implementation of this AR system, and use the Simultaneous Localization and Mapping (SLAM) technique to determine the geospatial point where the furniture will be the desired layout. The results of this application ifound that good minimum distance in detecting SLAM on the ground is 60 cm and can only be seen up to a maximum position of 45 ° from the Z axis of the camera’s initial position when tracking. This application runs on the Android mobile platform Introduction.

Corrosion of uranium in liquid water under contained conditions with a headspace argon overpressure. The ternary U + H2O(l) + Ar(g) system

The corrosion reaction of unirradiated uranium with deuterated liquid water under an argon (Ar) overpressure was investigated. Two samples were examined at two temperatures (55 °C and 70 °C) under an argon atmosphere and contained conditions. The rate of corrosion was derived by monitoring the pressure changes in the cell as a function of time (ascribed to D2 generation from U-corrosion). Post-corrosion examination was conducted using FIB and XRD. Measurements of water pH were made immediately after the experiments were stopped. From the analyses, it was concluded uranium-deuteride (UD3) was formed in the reaction products as part of the U‑D2O(l) -Ar(g) reaction. This result confirms the formation of uranium hydride/deuteride as part of the uranium-liquid water reaction in an enclosed environment, where deuteride forms through the reaction of U with oxidation-generated D2. From reaction rate behaviour combined with post-reaction surface/interface analysis, it is suggested that after a gas ‘threshold’ pressure limit is reached (~0.5 bar) UD3 formation is facilitated, leading to volume expansion and generation of stress in the overlying oxide. Breakage of this oxide would lead to direct exposure of UD3 and U to aqueous oxidation, leading to reaction rate enhancement.

POCKET MALAYSIA: Learning About States in Malaysia Using Augmented Reality

In era 4.0, teaching and learning are still in traditional method, which is using textbook. Hence, students become bored and easily to fall asleep during class. Therefore, researcher wish to develop an attractive and friendly-user augmented reality application as a learning aid for students. Pocket Malaysia uses AR system to learn about states in Malaysia. Student can learn in fun way through multimedia usage. There are several objectives to implement this research. Those are to identify which topic in Form One Geography Textbook is suitable to be implement in augmented reality concept, develop an augmented reality application that can help students recognize the name of states in Malaysia, location of states in Malaysia map and other details regarding each state in Malaysia through an interactive way and, evaluate usability of the application. This research uses quantitative method. The research approach is survey. About 15 students that are studying Geography subject in Universiti Pendidikan Sultan Idris (UPSI) are involve as sample through quota sampling. Overall, Pocket Malaysia is a good starting point for Geography subject in secondary school. This is because not many AR applications today are focusing on Geography subject. Based on the survey, many agree that it is easy to use although there is unclear instruction in scan section. The GUI also is quite pleasant along with the font size and colour selection. In general, it is successfully developed as it gave out the expected outcome. The weakness of this application should be improved in the future.

Augmented reality technology as a new source of competitive strengths in engineering products

The article analyzes opportunities for obtaining additional competitive strengths in engineering products due to the use of augmented reality technology for interactive information provision and support in terms of assembly, operation and maintenance for the products themselves as well as machinery units and production system components employed in the processes listed. The article also provides a short overview of equipment available on the market that can be viewed as a prototype for hardware and software complexes that provide informational support for technical personnel while the latter performs its job functions. It covers prospects of implementing informational systems that provide the operator with visualized supporting content online through the use of AR technology into the life cycle stages, processes of production, maintenance and operation of products and machinery equipment, as well as specialized applications. It also analyzes the necessary functional options and scenarios of using these applications, thus explaining the point of implementing them not as separate software products oriented on separate product units and equipment, but in the context of a unified information service of support for the production process, basically allowing the formation of a new production engineering instrument that goes along with the concept of the fourth technological revolution - reference-informational AR systems, the concept of use for which is universal to all industries and the consumer sector of the national economy. It analyzes the main limitations of the wide use of informational systems based on AR technology and gives grounds for its lessening midterm influence, based on, including but not limited to, the options for implementing new architectural solutions that are supported by the developing wireless data transfer technology (5G standard) as well as video compressing and transfer standards (MPEG-I). Based on the analysis of materials provided, rationale for implementing AR technology into the stages of machinery production and equipment life cycle is given, as well as new opportunities for obtaining their additional competitive strengths and relevance of information security of the corresponding reference-informational systems based on AR technology.

Comparative Experiments on Simulated Tornado Experience via Virtual Reality and Augmented Reality

In Japan, a tornado is an infrequent natural disaster; however, tremendous winds can cause considerable damage. To prepare for such events, simulated tornado experience (STE) considering tremendous wind as a major hazard and incorporating evacuation plans must be provided. However, introduction of a large wind generator in STE is difficult. We developed simple VR and AR systems (VR-STE and AR-STE) that render STE by realistically simulating tornadoes and conducted comparative experiments. We set research questions that aimed to clarify how VR- and AR-STEs differ from STE, which expresses tornadoes with audiovisual effects and real, tremendous wind generated by a large wind generator. The survey variables were fear, self-efficacy, and learning motivation to cope with a tornado. The experimental results revealed that audiovisual effects can retain learners’ fear of a tornado and influence learners’ self-efficacy and learning motivation. Furthermore, VR-STE is more suitable than AR-STE in terms of controlling fear and system operation.

Review on Augmented Reality in Oral and Cranio-Maxillofacial Surgery: Toward “Surgery-Specific” Head-Up Displays

In recent years, there has been an increasing interest towards the augmented reality as applied to the surgical field. We conducted a systematic review of literature classifying the augmented reality applications in oral and cranio-maxillofacial surgery (OCMS) in order to pave the way to future solutions that may ease the adoption of AR guidance in surgical practice. Publications containing the terms “augmented reality” AND “maxillofacial surgery”, and the terms “augmented reality” AND “oral surgery” were searched in the PubMed database. Through the selected studies, we performed a preliminary breakdown according to general aspects, such as surgical subspecialty, year of publication and country of research; then, a more specific breakdown was provided according to technical features of AR-based devices, such as virtual data source, visualization processing mode, tracking mode, registration technique and AR display type. The systematic search identified 30 eligible publications. Most studies (14) were in orthognatic surgery, the minority (2) concerned traumatology, while 6 studies were in oncology and 8 in general OCMS. In 8 of 30 studies the AR systems were based on a head-mounted approach using smart glasses or headsets. In most of these cases (7), a video-see-through mode was implemented, while only 1 study described an optical-see-through mode. In the remaining 22 studies, the AR content was displayed on 2D displays (10), full-parallax 3D displays (6) and projectors (5). In 1 case the AR display type is not specified. AR applications are of increasing interest and adoption in oral and cranio-maxillofacial surgery, however, the quality of the AR experience represents the key requisite for a successful result. Widespread use of AR systems in the operating room may be encouraged by the availability of “surgery-specific” head-mounted devices that should guarantee the accuracy required for surgical tasks and the optimal ergonomics.

Closed-loop augmented reality towards accurate human-robot collaboration

Augmented Reality provides an interactive approach to combining the physical manufacturing environment with the computer-generated virtuality. However, it is still challenging to establish an efficient AR system due to the complexity of the actual manufacturing environment, and difficulties in human-robot collaboration. In this research, a feasible AR system is developed with a novel closed-loop structure. A feasible AR-based human-robot interaction method is also developed based on the HoloLens device, together with an advanced compensation mechanism towards accurate robot control. The proposed work is implemented and validated through case studies, and quantifiable performance assessment on system response time, compensation accuracy, etc.

IO(X2Π)-Ar cluster: ab initio potential energy surface and dynamical computations.

Iodine oxide (IO) is an important tropospheric molecule. In the present paper, we mapped the potential energy surfaces (PESs) of the doubly degenerate IO(X2Π)-Ar van der Waals system using single- and double-excitation coupled cluster approaches with non-iterative perturbation treatment of triple excitations [RCCSD(T)] extrapolated to the complete basis set (CBS) limit. In addition to bent local minima, we identified a linear Ar-IO complex as a global minimum. Afterwards, we performed scattering calculations on these PESs, considering the non-zero spin-orbit contribution and the Renner-Teller effect. The integral cross-sections exhibit an oscillatory structure vs. the final rotational state, as already observed for the NO(X2Π)-Ar system. Moreover, computations reveal that the Ar-IO complex is stable toward dissociation into IO and Ar. Therefore, it can be found in the atmosphere and participates in iodine compound physical chemical processes occurring there.

Asymptotic behavior of the cross-dependence measures for bidimensional AR(1) model with $\alpha $-stable noise

In this paper, we consider a bidimensional autoregressive model of order 1 with $\alpha-$stable noise. Since in this case the classical measure of dependence known as the covariance function is not defined, the spatio-temporal dependence structure is described using the alternative measures, namely the codifference and the covariation functions. Here, we investigate the asymptotic relation between these two dependence measures applied to the description of the cross-dependence of the bidimensional model. We demonstrate the case when the dependence measures are asymptotically proportional with the coefficient of proportionality equal to the parameter $\alpha$. The theoretical results are supported by illustrating the asymptotic behavior of the dependence measures for two exemplary bidimensional $\alpha-$stable AR(1) systems.

Research on Augmented Reality Method Based on Improved ORB Algorithm

Aiming at the problems of time-consuming three-dimensional registration algorithm in augmented reality system, low accuracy of feature point matching and poor registration effect, an improved ORB (S-ORB) algorithm is proposed and applied to the Majiayao painted pottery augmented reality system. Firstly, the scale space is established by Gaussian filtering and downsampling, and the feature points are extracted by FAST corner detection. Secondly, the descriptors of feature points are calculated by rBFEF algorithm. Finally, the feature matching set is obtained by hamming distance and the mismatching point is eliminated by RANSAC algorithm to complete the three-dimensional registration. Make the virtual information stack correctly added to the real scene. The experimental results show that the S-ORB algorithm is better than the ORB, SURF and BRISK algorithms in time and accuracy when the target position is rotated and scaled. It has better real-time and robustness in the AR system of the painted pottery.

PLASMA PARAMETERS AND COMPOSITION IN CF4 + O2 + Ar AND CHF3 + O2 +Ar IN REACTIVE ION ETCHING PROCESSES

The comparative analysis of both CF4+O2+Ar and CHF3+O2+Ar plasma systems under the typical conditions of reactive ion etching of silicon and silicon-based compounds was carried out. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained using a description of Langmuir probe diagnostics and 0-dimensional (global) plasma modeling. As a presented in the literature, both experimental and modeling procedures were carried out at constant total gas pressure, input power, bias power. The obtained results allowed one 1) to figure out the influence of oxygen on steady-state densities of plasma active species through the kinetics of both electron-impact and atom-molecular reactions; 2) to understand the features of fluorine atoms and fluorocarbon radicals kinetics which determine chemical activity and polymerization ability of plasmas in respect to treated surfaces; 3) to perform the model-bases analysis of heterogeneous process kinetics (etching, polymerization, polymer destruction) which determine the overall etching regime and output parameters. It was found that the substitution of argon for oxygen in both gas mixtures 1) results in monotonic increase in fluorine atom density; 2) is accompanied by decreasing polymerization ability of a gas phase and 3) causes the rapid (by about two orders of magnitude at ~ 20% О2) decrease in fluorocarbon polymer film thickness with the higher values for CHF3+O2+Ar system.

Multisensory based AR System for Education of Cultural Heritage

Multisensory based AR System for Education of Cultural Heritage

Spectroscopy of atomic orbital sizes using bi-elliptical high-order harmonic generation

We report that high-order harmonic generation (HHG) of atoms driven by $\ensuremath{\omega}\text{\ensuremath{-}}2\ensuremath{\omega}$ bi-elliptical pumps exhibits a substantial sensitivity to variation of the spatial extent of the participating valence orbitals and effective potential. We identify the physical mechanisms responsible for this enhanced sensitivity through theoretical investigations in atomic He, Ne, Ar, and Kr systems using several quantum models. We demonstrate this size sensitivity experimentally by measuring significant disparities in the bi-elliptical HHG spectra of atomic Ar and Kr, which have relatively similar ionization potentials, but substantially different $p$-shell sizes and effective potentials. This result may be useful for ultrafast spectroscopy which is sensitive to effective potentials and orbitals.

The geologic history of Vesta inferred from combined 207Pb/206Pb and 40Ar/39Ar chronology of basaltic eucrites

Eucrites represent samples of mafic crust of the parent body, likely Vesta, and record a complex geologic history involving magmatism, metamorphism, impact processing, and metasomatism. For better understanding of the geologic history, we present combined 207Pb/206Pb and 40Ar/39Ar chronology of four basaltic eucrites showing distinct petrologic features: Agoult, an equilibrated eucrite with granulitic textures; Camel Donga, a brecciated equilibrated eucrite enriched in metallic iron; DaG 380, a partially equilibrated monomict eucrite; and NWA 049, a metasomatized polymict eucrite comprising mostly unequilibrated clasts. The 207Pb/206Pb dating in combination with the acid washing technique was applied to pyroxene-rich and plagioclase-rich fractions, while the 40Ar/39Ar dating was performed mainly on plagioclase grains using the laser incremental heating method. The Pb isotopic data for acid leaching residues are more radiogenic than those for acid washes, reflecting efficient removal of non-radiogenic Pb components by the acid washing. Among the residues, however, only those of the Agoult and Camel Donga plagioclase-rich fractions yielded isochrons, rather than errorchrons, with 207Pb/206Pb ages of 4532.39 ± 0.87 Ma and 4515.43 ± 0.42 Ma, respectively. The trace element systematics further suggest that these residues essentially represent contaminant oxide minerals such as ilmenite and chromite rather than plagioclase. On the other hand, the Ar isotopic data for Agoult and Camel Donga yielded plateau ages with weighted means of 4494 ± 9 Ma and 3749 ± 25 Ma, in contrast to those for DaG 380 and NWA 049 that did not return any plateau. The 207Pb/206Pb and 40Ar/39Ar ages of Agoult are interpreted to reflect the time of the U–Pb and K–Ar system closure during a prolonged thermal metamorphism. By combining the ages reported here and in the literature with the calculated closure temperatures, the cooling rate of Agoult is determined to be 11 ± 2 °C/Ma. This cooling rate corresponds to a burial depth of 10–20 km, indicating that granulitic eucrites were originally crystallized near the surface and were subsequently buried and metamorphosed. The ∼20 Ma younger 207Pb/206Pb ages of Camel Donga than Agoult are considered to reflect delayed burial metamorphism in the source region, whereas the plateau 40Ar/39Ar age would record the time of an impact causing brecciation and efficient Ar-degassing of the buried crust. Furthermore, the model 207Pb*/206Pb* dates calculated for acid-washed pyroxenes imply that the burial metamorphism of Agoult and DaG 380 were broadly contemporaneous and also that NWA 049 was metasomatized by fluids within the uppermost crust later than 4.4 Ga.

Requirements and System Aspects of AR-Head-Up Displays

This paper describes the requirements engineering for AR-HUDs and provides proposals to solve issues encountered in moving from conventional HUDs to AR-HUDs. These topics can be transferred to consumer electronics AR systems. The field of view for AR support on highways should be at least 20° × 20° and 60° × 40° in cities. This is about an order of magnitude larger than today and will be achievable by using holographic subassemblies for practical HUD volumes. AR content is not only projected on the road but also on bright buildings. For such use cases, the required luminance was calculated for a reasonable contrast ratio of 3 : 1 as 40,000 cd/m2. New HUD display technologies are needed to reach this value.

HoloLens-Based AR System with a Robust Point Set Registration Algorithm.

By the standard of today’s image-guided surgery (IGS) technology, in order to check and verify the progress of the surgery, the surgeons still require divert their attention from the patients occasionally to check against the display. In this paper, a mixed-reality system for medical use is proposed that combines an Intel RealSense sensor with Microsoft’s Hololens head-mounted display system, for superimposing medical data onto the physical surface of a patient, so the surgeons do not need to divert their attention from their patients. The main idea of our proposed system is to display the 3D medical images of the patients on the actual patients themselves by placing the medical images and the patients in the same coordinate space. However, the virtual medical data may contain noises and outliers, so the transformation mapping function must be able to handle these problems. The transform function in our system is performed by the use of our proposed Denoised-Resampled-Weighted-and-Perturbed-Iterative Closest Points (DRWP-ICP) algorithm, which performs denoising and removal of outliers before aligning the pre-operative medical image data points to the patient’s physical surface position before displaying the result using the Microsoft HoloLens display system. The experimental results shows that our proposed mixed-reality system using DRWP-ICP is capable of performing accurate and robust mapping despite the presence of noise and outliers.