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Robotic surgery is preferred over open or laparoscopic surgeries due to its intuitiveness and convenience. However, prolonged use of surgical robots can cause neck pain and joint fatigue in wrist and fingers. Also, input systems are bulky and difficult to maintain. To resolve these issues, we propose a novel input module based on real-time 3D hand tracking driven by RGB images and MediaPipe framework to control surgical robots such as patient side manipulator (PSM) and endoscopic camera manipulator (ECM) of da Vinci research kit. In this paper, we explore the mathematical basis of the proposed 3D hand tracking module and provide a proof-of-concept through user experience (UX) studies conducted in a virtual environment. End-to-end latencies for controlling PSM and ECM were 170 ± 10 ms and 270 ± 10 ms, respectively. Of fifteen novice participants recruited for the UX study, thirteen managed to reach a qualifiable level of proficiency after 50 min of practice and fatigue of hand and wrist were imperceivable. Therefore, we concluded that we have successfully developed a robust 3D hand tracking module for surgical robot control and in the future, it would hopefully reduce hardware cost and volume as well as resolve ergonomic problems. Furthermore, RGB image driven 3D hand tracking module developed in our study can be widely applicable to diverse fields such as extended reality (XR) development and remote robot control. In addition, we provide a new standard for evaluating novel input modalities of XR environments from a UX perspective. [ABSTRACT FROM AUTHOR]

Robot-assisted surgery platforms are utilized globally thanks to their stereoscopic vision systems and enhanced functional assistance. However, the necessity of ergonomic improvement for their use by surgeons has been increased. In surgical robots, issues with chronic fatigue exist owing to the fixed posture of the conventional stereo viewer (SV) vision system. A head-mounted display was adopted to alleviate the inconvenience, and a virtual vision platform (VVP) is proposed in this study. The VVP can provide various critical data, including medical images, vital signs, and patient records, in three-dimensional virtual reality space so that users can access medical information simultaneously. An availability of the VVP was investigated based on various user evaluations by surgeons and novices, who executed the given tasks and answered questionnaires. The performances of the SV and VVP were not significantly different; however, the craniovertebral angle of the VVP was 16.35° higher on average than that of the SV. Survey results regarding the VVP were positive; participants indicated that the optimal number of displays was six, preferring the 2 × 3 array. Reflecting the tendencies, the VVP can be a neoconceptual candidate to be customized for medical use, which opens a new prospect in a next-generation surgical robot. [ABSTRACT FROM AUTHOR]

To determine the sources and pathways of lead (Pb) and zinc (Zn) in river sediments contaminated with metals from mining and smelting activities, metal concentrations and Pb and Zn isotope ratios were measured in river water and sediment, and potential metal contaminant samples (imported Zn concentrates, smelting wastes, soils around the smelter, mine ores, and riverside tailings). Zn and cadmium (Cd) concentrations in river water and sediment samples were 30- and 11–25-fold higher, respectively, near the smelter than upstream, while a 6-fold increase in sediment Pb concentrations was detected over the same region. Sediment samples near the smelter (207Pb/206Pb = 0.8638 and 208Pb/206Pb = 2.0960) were observed to have a different Pb isotopic composition from upstream of the smelter (207Pb/206Pb = 0.8322 and 208Pb/206Pb = 2.0502), with δ66Zn values increasing from –0.01 to 0.82‰. Analysis of Pb and Zn isotopes and concentrations revealed that dust-contaminated soils were a major Pb source, and baseline sediments were found to be contaminated by regional mining tailings. For Zn in sediments, the main Zn sources were groundwater-derived Zn (δ66Zn = 1.02 ± 0.43‰, n = 4), dust-contaminated soils (δ66Zn = –0.18 ± 0.08‰, n = 3), and tailings-contaminated sediments (δ66Zn = 0.01 ± 0.07‰, n = 10). Endmember mixing model results showed that dust-contaminated soils contributed 78% and 64% of sediment Pb and Zn, respectively, within 2 km of the Zn smelter, decreasing to negligible levels after 47.1 km downstream. Downstream of the smelter, groundwater-derived Zn contributed 54% of sediment Zn, whereas tailings contaminated sediments contributed 70% and 25% of Pb and Zn, respectively. [ABSTRACT FROM AUTHOR]

The intraoperative estimated blood loss (EBL), an essential parameter for perioperative management, has been evaluated by manually weighing blood in gauze and suction bottles, a process both time-consuming and labor-intensive. As the novel EBL prediction platform, we developed an automated deep learning EBL prediction model, utilizing the patch-wise crumpled state (P-W CS) of gauze images with texture analysis. The proposed algorithm was developed using animal data obtained from a porcine experiment and validated on human intraoperative data prospectively collected from 102 laparoscopic gastric cancer surgeries. The EBL prediction model involves gauze area detection and subsequent EBL regression based on the detected areas, with each stage optimized through comparative model performance evaluations. The selected gauze detection model demonstrated a sensitivity of 96.5% and a specificity of 98.0%. Based on this detection model, the performance of EBL regression stage models was compared. Comparative evaluations revealed that our P-W CS-based model outperforms others, including one reliant on convolutional neural networks and another analyzing the gauze’s overall crumpled state. The P-W CS-based model achieved a mean absolute error (MAE) of 0.25 g and a mean absolute percentage error (MAPE) of 7.26% in EBL regression. Additionally, per-patient assessment yielded an MAE of 0.58 g, indicating errors < 1 g/patient. In conclusion, our algorithm provides an objective standard and streamlined approach for EBL estimation during surgery without the need for perioperative approximation and additional tasks by humans. The robust performance of the model across varied surgical conditions emphasizes its clinical potential for real-world application. [ABSTRACT FROM AUTHOR]

The hot corrosion behaviors of Inconel alloys with different Cr contents (Inconel 600, 601, and 690), which are used widely in nuclear plants, were investigated in molten LiCl–Li2O salts. The hot corrosion behaviors were studied by measuring the mass and attack depth changes, surface and cross-sectional morphologies and elemental distributions, and compositional changes at the subscale and substrate scale as well as the spalled oxide scale. At 288 h, the weight losses of Inconel 601 and Inconel 690 were approximately four and twelve times higher, respectively, than that of Inconel 600. The corrosion products of all tested alloys were Cr2O3, NiO, and FeCr2O4. Inconel 600, which exhibited a dense and continuous external corrosion layer and an internal corrosion layer with localized corrosion behavior, exhibited superior corrosion resistance compared with those of Inconel 601 and 690, which showed a spalled external corrosion layer and an internal corrosion layer with uniform corrosion behavior. Thus, the corrosion resistance of the Inconel alloys tested in the hot lithium molten salts in an oxidizing atmosphere is closely related to the contents of the primary alloying elements in the alloys. Of the various alloys analyzed in this study, Inconel 600 exhibited the highest corrosion resistance. Thus, a Cr content of 16.30 wt% or less, Ni content of at least 73.66 wt%, and Fe content considerably lower than 8.15 wt% can result in excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

This study investigates the fuel atomization effect of alternating magnetic field (AMF)-based preprocessing equipment that promotes the atomization of automobile fuel. Two coils are connected to the output terminal of the preprocessing equipment and wound on an STS 316 L fuel pipe in the form of a solenoid. Positive sine waves and negative sine waves are output to the two coils, and the AMF in the solenoids causes atomization of the fuel flowing inside the pipe. A spray visualization experiment was conducted with fine particles sprayed from the injector, and the spray arrival distance, spray angle, and spray area were recorded. The information was analyzed to digitize the spray penetration, angle, and area at 2 ms after firing the injector. The fuel atomization effect of the AMF-based preprocessing equipment was also investigated Gasoline was used as the fuel, and the fuel atomization effect was analyzed using the number of windings around the STS 316 L fuel pipe, the frequency applied to the coil, the distance between the two solenoid coils, and the fuel injection pressure as variables. [ABSTRACT FROM AUTHOR]

Titanium metal preparation from titanium dioxide (TiO2) has been the subject of numerous studies to overcome the chlorination processes at the heart of the Kroll process. In this study, an alumino-magnesiothermic reduction approach is employed to obtain a Ti-rich ingot via the combustion of an exothermic mixture of TiO2–KClO4–Al(Mg)-KClO4–CaF2 composition in argon. The combustion temperatures are measured, and the reaction patches are highlighted. The synthesis conditions of the Ti-rich ingot were carefully examined depending on the Al particle size, Al/Mg ratio, TiO2 precursor type, and CaF2 concentration. XRD analysis states that the ingot obtained under optimized experimental conditions is single-phase Ti metal. ICP-MS analysis revealed residual Al and O in the Ti ingot with 3.5 and 4.0 wt pct content, respectively. [ABSTRACT FROM AUTHOR]

Robot-assisted surgery (RAS) using the da Vinci surgical system (dVSS) has been widely performed owing to its high-definition stereoscopic visualization and improved maneuverability, which has been developed from minimally invasive surgery. However, there was motivation to resolve the chronic fatigue suffered by surgeons because of stereo viewer, the vision system of the dVSS. Reflecting the clinical opinions, a virtual reality (VR) goggle was proposed to enhance the convenience by replacing the stereo viewer, and its applicability was investigated. Based on the da Vinci research kit, validation of the VR goggle was performed by analyzing the condition of its use and implementing the performance assessment. In addition, user evaluations, such as performance analysis, questionnaire surveys, and ergonomic analysis, were conducted to determine the difference in the performance and satisfaction between the stereo viewer and VR goggle. Following the IRB approval, a retrospective analysis of the results was performed. Based on the comparison between the vision systems, the VR goggle was evaluated positively by the surgeons and novices. Satisfaction with the ergonomic properties of the VR goggle averaged 3.9 on a five-point Likert scale, and there was no significant difference in the performance when using the VR goggle and stereo viewer in both groups. Adopting the VR goggle, the volume of the vision system could be decreased by 87.6%. Considering that the VR goggle was better than the stereo viewer in terms of satisfaction and ergonomic analysis with analogous performance, it has the main contribution that the VR goggle can be a promising candidate as a new vision baseline to research the enhancements of the RAS platform in further studies. [ABSTRACT FROM AUTHOR]

Titanium suboxides with the general formula TinO2n−1 (n > 1.0), also referred to as Magnéli phases, have been the subject of numerous studies due to their unique properties. Titanium low oxygen suboxides located at n = 1 (TiO) or below (Ti6O, Ti3O and Ti2O) are no less important; however, there is a lack of research on the synthesis of such materials. Therefore, in this article, the combustion process in a TiO2-KClO4-kAl-Flux exothermic system for 0.5 ≤ k ≤ 4.0 (k is moles of Al) is investigated experimentally and thermodynamically to synthesize TinO2n−1 ingots in the 0.5 to 1.0 range of n. The synthesis temperatures and equilibrium reaction phases are calculated with and without a KClO4 booster and several fluxes (CaF2, NaF, CaO and Na3AlF6), which are used to melt the reaction product and achieve the self-separation of the TinO2n−1 ingot from the Al2O3-containing slag. The formation TiO, Ti2O, Ti3O and Ti6O phases is confirmed via XRD analysis and the effectiveness of fluxes is highlighted. [ABSTRACT FROM AUTHOR]

The high-temperature corrosion behavior of anode current collectors in liquid Ag under an oxidizing atmosphere was investigated. The weight gain in oxygen was higher than that of liquid Ag because of the effective barrier formed by Ag-rich layer coated on the corrosion layer. The thickness of the corrosion layer under oxygen was approximately twice that of the layer developed under liquid Ag because of the effective barrier originating from the Ag-rich layer. The corrosion products on the surface of the specimens in both oxygen and liquid Ag were Al2O3 and FeAl2O4 from 24 to 168 h. The surface morphology that was developed on the scale of the corroded layer represented a buckle structure in liquid Ag and a convoluted structure in oxygen, which resulted from the lateral growth of the oxide. This study proved the improved stability and cost-effectiveness of using FeCrAl alloy as a current collector in a solid oxide membrane system. [ABSTRACT FROM AUTHOR]

Effect-directed analysis (EDA) has become useful for identification of toxicant(s) that occur in mixtures in the environment, especially those that are causative agents of specific adverse effects. Here, we summarize and review EDA methodology including preparation of samples, biological analyses, fractionations, and instrumental analyses, highlighting key scientific advancements. A total of 63 documents since 1999 (Scopus search) including 46 research articles, 13 review papers, and 4 project descriptions, have been collected and reviewed in this study. At the early stage (1999-2010), most studies that applied EDA focused on organic extracts of freshwater and coastal contaminated sediments and wastewater. Toxic effects were often measured using cell-based bioassays ( in vitro) and the causative chemicals were identified by use of low resolution gas chromatography with mass selective detector (GCMSD). More recently (2010-present), EDA has been extended to various matrices such as biota, soil, crude oil, and suspended solids and techniques have been improved to include determination of bioavailability in vivo. In particular, methods for non-target screenings of organic chemicals in environmental samples using cutting-edge instrumentation such as time of flight-mass spectrometry (ToF-MS), Fourier transform-ion cyclotron resonance (FT-ICR), and Orbitrap mass spectrometer have been developed. This overview provides descriptions of recent improvements of EDA and suggests future research directions based on current understandings and limitations. [ABSTRACT FROM AUTHOR]

Despite literature evidence suggesting the importance of sampling methods on the properties of sediment pore waters, their effects on the dissolved organic matter (PW-DOM) have been unexplored to date. Here, we compared the effects of two commonly used sampling methods (i.e., centrifuge and Rhizon sampler) on the characteristics of PW-DOM for the first time. The bulk dissolved organic carbon (DOC), ultraviolet-visible (UV-Vis) absorption, and excitation-emission matrixes coupled with parallel factor analysis (EEM-PARAFAC) of the PW-DOM samples were compared for the two sampling methods with the sediments from minimal to severely contaminated sites. The centrifuged samples were found to have higher average values of DOC, UV absorption, and protein-like EEM-PARAFAC components. The samples collected with the Rhizon sampler, however, exhibited generally more humified characteristics than the centrifuged ones, implying a preferential collection of PW-DOM with respect to the sampling methods. Furthermore, the differences between the two sampling methods seem more pronounced in relatively more polluted sites. Our observations were possibly explained by either the filtration effect resulting from the smaller pore size of the Rhizon sampler or the desorption of DOM molecules loosely bound to minerals during centrifugation, or both. Our study suggests that consistent use of one sampling method is crucial for PW-DOM studies and also that caution should be taken in the comparison of data collected with different sampling methods. [ABSTRACT FROM AUTHOR]

The precipitation behaviors of intergranular carbides on various types of grain boundaries and their effect on tensile properties at room temperature were investigated systematically in Inconel 690 tubes. Precipitates of intergranular chromium carbide were identified as Cr-rich MC. It was observed that the MC carbide behavior is obviously influenced by grain boundary character and interfacial energy. The intergranular MC carbides were suppressed on low-angle boundaries and coincidence-site lattice boundaries. Plenty of MC carbides precipitated at random high-angle boundaries with high interfacial energy. With increasing aging time, the precipitated carbides became coarse and grew into the matrix near grain boundaries. The ultimate tensile strength and elongation of the Inconel 690 tube solution annealed at 1373 K (1100 °C) for 15 minutes were 671.2 MPa and 47.2 pct, respectively. After aging treatment, the ultimate tensile strength and elongation drastically decreased with increasing aging time. The tensile test generated a number of cracks at the grain boundaries due to coarse intergranular MC carbides near the fracture. Both the decrease of ultimate tensile strength and elongation of the aged Inconel 690 tube were mainly caused by breaking of the coarse MC carbide and reduced chromium concentration in the matrix. [ABSTRACT FROM AUTHOR]

In this work, an Al/Cu composite was fabricated using repeated hydrostatic extrusions with a semi-die angle of 45° at a temperature of 200°C. During the repeated hydrostatic extrusion process, an intermetallic layer of 1 μm was generated at the Al/Cu interface. The intermetallic reinforcement layer formation was studied via field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The reinforcement layers consisted of AlCu and AlCu phases. The thermal conductivity and coefficient of thermal expansion of the Al/Cu composites were determined via laser flash analyzer and thermal mechanical analyzer. The thermal conductivities in the longitudinal direction and cross direction were 267.8 W/mK and 209.9 W/mK at room temperature, respectively. The coefficient of thermal expansion at temperatures between room temperature and 450°C was 18.3 μm/m°C. The ultimate tensile strength of the Al/Cu composite is 102.8 MPa. The anisotropic physical properties of the prepared composite were mainly a result of the unique directional microstructure formed during the repeated extrusion process. [ABSTRACT FROM AUTHOR]

High-purity Nd metal was recovered from waste Nd-Fe-B magnet by the molten salt electrowinning process with chemical pretreatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), cyclic voltammetry (CV), chronopotentiometry (CP), and inductively coupled plasma-atomic emission spectrometer (ICP/AES) were used to characterize the deposit and electrochemical behaviors. The results show that NdF is effectively synthesized from the Nd-Fe-B magnet using HCl solution and NHF. During the chemical treatment of the waste magnet, iron impurity is eliminated as a soluble [NH][FeF] complex. Electrowinning using NdF in LiF molten salt shows that Nd metal is deposited from the electrolyte on the cathode at the reduction potentials ranging from −1.48 to −1.35 V (vs. W) with the concentration change of NdF. The final purity of Nd metal deposit is higher than 99.78 %. [ABSTRACT FROM AUTHOR]

For developing a complementary test organism to sea urchin during winter in Korea, sensitivities of sperm, embryo, and larvae of Asterias amurensis to un-ionized ammonia were evaluated. The ECs (Mean ± SD, n = 3) for fertilization and development were 169 ± 62 and 70 ± 19 μg/L, respectively. The 48, 72, and 96-h LCs for larval survival were 1,674 ± 583, 498 ± 221, and 336 ± 107 μg/L, respectively. The sensitivities of fertilization, development, and larval survival tests with A. amurensis are higher than or comparable to those of sea urchin and other taxonomic groups. Therefore, fertilization, development, and larval survival tests using A. amurensis are suitable for assessing pore water toxicity of marine sediments in Korea. [ABSTRACT FROM AUTHOR]

Copper–zinc alloy (Cu/Zn) powders with different Zn to Cu molar ratios were prepared by the combustion synthesis technique using a CuO + 0.15(C2H4)n + kZn (0.2 ≤ k ≤ 1.6 mol) reactive mixture. Depending on the Zn concentration, the combustion wave developed a temperature between 950 and 1040 °C and passed through the sample with a speed of 0.04–0.08 cm/s, resulting in almost single-stage temperature distributions. Cu/Zn alloy powders with Zn concentrations ranging from 0.5 to 45 wt% were obtained. It was shown that alloy particles become spherical and well dispersed with increasing Zn concentration. Inert dilution test with KCl salt was also performed to determine the influence of temperature degradation in the combustion wave on the morphology and composition of alloy powders. [ABSTRACT FROM PUBLISHER]

The high temperature corrosion behavior of N07263, N06600, and N06625 in LiCl-LiO molten salt was investigated at temperatures ranging from 650 to 850 °C in a glove box. The high temperature corrosion behavior was observed using measurements of the oxide morphology and thickness, the extent of internal corrosion, and the compositional changes in the scale and in the substrate. Corrosion tests were performed, and these demonstrated that the main corrosion products were Fe(Ni,Co), FeNi, and LiCrO. The internal corrosion of N07263 was localized, while that of N06600 maintained intergranular corrosion throughout the test temperature range. N06625 exhibited uniform intergranular corrosion behaviors at low and high temperatures. N07263 exhibited superior corrosion resistance, as evidenced by its corrosion layer which was more continuous, dense, and adherent when compared with those of N06600 and N06625. [ABSTRACT FROM AUTHOR]

In this study, the cyclic corrosion behavior of N06230, N07263, and N06625 in a LiCl-LiO molten salt was investigated at 650 °C in argon atmosphere. The cyclic corrosion behavior was observed through measurements of the oxide morphology and thickness, the extent of internal corrosion, and compositional changes in the oxide scale and the substrate. The corrosion products in the surface corrosion layers of N07263 were (Ni,Co)O, (Ni,Co)CrO, CrO, and TiO and those in the surface corrosion layers of N06230 were NiO, NiCrO, and CrO, while NiO, NiCrO, CrNbO, and CrO were identified as the corrosion products of N06625. The internal corrosion behavior of N07263 was localized, while N06230 and N06625 showed uniform corrosion. N07263 exhibited superior corrosion resistance as its corrosion layer was more continuous, dense, and adherent as compared to those of N06230 and N06625. [ABSTRACT FROM AUTHOR]

A series of experiments were conducted to develop standard test organisms and test protocols for measuring sediment toxicity using candidate amphipods such as Mandibulophoxus mai, Monocorophium acherusicum, Haustorioides indivisus, and Haustorioides koreanus, which are indigenous to Korea. The relevant association of test species with sediment substrates was one of the important factors in sediment bioassay. The indigenous amphipods M. mai and M. acherusicum were well associated with test sediments when they were exposed to various sediment substrates from sand to mud. The tolerant limits to various physico-chemical factors affecting bioassay results such as temperature, salinity and ammonia, as well as sensitivities to reference toxicant and contaminated sediments, were investigated using M. mai and M. acherusicum in the present study. These amphipods were tolerant to relatively wide ranges of salinity (10~30 psu) and ammonia (<50 ppm), and displayed relevant sensitivity to temperature as well. They are more sensitive to Cd, the reference toxicant, when compared to the standard test species used in other countries. Field-sediment toxicity tests revealed that M. mai would be more sensitive to sediment-associated pollutants than M. acherusicum, while the sensitivity of M. acherusicum was comparable to that of Leptocheirus plumulosus, which has been used as a standard test species in the United States of America. Overall results of this first attempt to develop an amphipod sediment toxicity test protocol in Korea indicated that M. mai and M. acherusicum would be applicable in the toxicity assessment of contaminated sediments, following the further evaluation encompassing various ecological and toxicological studies in addition to test method standardization. [ABSTRACT FROM AUTHOR]

Simultaneous synthesis and densification of NiAl and Ni3Al from elemental powders of Ni and Al was investigated. Combustion synthesis was carried out under the uniaxial compressive pressure and preheating of die. It was shown that both the compressive pressure and preheating of die strongly affect the density, the grain size and the hardness of NiAl and Ni3Al product. A high relative density of NiAl and Ni3Al products as much as 99.8% was achieved under compressive pressure of 275 MPa and preheating temperature of 600°C. [ABSTRACT FROM AUTHOR]

This paper demonstrates for the first time the fabrication of Zr-Cu alloy ingots from a Hf- free ZrO2 precursor in a molten CaCl2 medium to recover nuclear-grade Zr. The reduction of ZrO2 in the presence of CaO was accelerated by the formation of Ca metal in the intermediate stage of the process. Tests conducted with various amounts of ZrO2 indicate that the ZrO2 was reduced to the metallic form at low potentials applied at the cathode, and the main part of the zirconium was converted to a CuZr alloy with a different composition. The maximum oxygen content values in the CuZr alloy and Zr samples upon using liquid Cu were less than 300 and 891 ppm, respectively. However, Al contamination was observed in the CuZr during the electroreduction process. In order to solve the Al contamination problem, the fabrication process of CuZr was performed using the metallothermic reduction process, and the produced CuZr was used for electrorefining. The CuZr alloy was further purified by a molten salt electrorefining process to recover pure nuclear-grade Zr in a LiF-Ba2ZrF8-based molten salt, the latter of which was fabricated from a waste pickling acid of a Zr clad tube. After the electrorefining process, the recovered Zr metal was fabricated into nuclear-grade Zr buttons through arc melting following a salt distillation process. The results suggest that the removal of oxygen from the reduction product is a key reason for the use of a liquid CaCu reduction agent. [ABSTRACT FROM AUTHOR]