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This paper tackles issues with controller synthesis of disturbed robot manipulators using adaptive sliding mode control (ASMC) and time-delay control (TDC) schemes. For robust control of dynamic system consisting of complex nonlinear functions, this paper proposes a novel ASMC method that uses a novel sliding variable-based adaptive law. The proposed adaptive law employs both function-based and rate-based decreasing law near the sliding surface to improve tracking performance while maintaining or even reducing chattering. The proposed sliding variable also incorporates additional terms for the position error and their time derivatives to compensate for time-delay estimation (TDE) errors induced from TDC methods. For the stability analysis of the robot manipulator controlled by the proposed ASMC, this paper proves uniformly ultimately bounded (UUB) stability of the sliding variable. Numerical simulation and experimental results demonstrate the effectiveness of the proposed ASMC in terms of tracking performance.

Abstract Background A considerable number of studies has been carried out to develop alloplastic bone graft materials such as hydroxyapatite (HAP) that mimic the hierarchical structure of natural bones with multiple levels of pores: macro-, micro-, and nanopores. Although nanopores are known to play many essential roles in natural bones, only a few studies have focused on HAPs containing them; none of those studies investigated the functions of nanopores in biological systems. Method We developed a simple yet powerful method to introduce nanopores into alloplastic HAP bone graft materials in large quantities by simply pressing HAP nanoparticles and sintering them at a low temperature. Results The size of nanopores in HAP scaffolds can be controlled between 16.5 and 30.2 nm by changing the sintering temperature. When nanopores with a size of ~ 30.2 nm, similar to that of nanopores in natural bones, are introduced into HAP scaffolds, the mechanical strength and cell proliferation and differentiation rates are significantly increased. The developed HAP scaffolds containing nanopores (SNPs) are biocompatible, with negligible erythema and inflammatory reactions. In addition, they enhance the bone regeneration when are implanted into a rabbit model. Furthermore, the bone regeneration efficiency of the HAP-based SNP is better than that of a commercially available bone graft material. Conclusion Nanopores of HAP scaffolds are very important for improving the bone regeneration efficiency and may be one of the key factors to consider in designing highly efficient next-generation alloplastic bone graft materials.

Verification of the system is essential during the development of a tractor; however, there are cost and time limitations when verification is performed on an actual tractor. To solve this problem, we developed a tractor model for real-time simulation to verify the gear shift performance of the tractor and evaluate the control algorithm. This study examined and modeled a dual-clutch transmission (DCT)-type 105 kW class tractor. The proportional control valve, synchronizer, and clutch were modeled to accurately implement the shift behavior, and the developed individual model was verified based on actual individual product test data. The 45 s driving simulation was conducted to confirm whether real-time simulation of the entire developed tractor model was possible and whether it simulated the behavior of the target tractor well. The driving simulation results confirmed that the driving speed of the tractor model matched the engine speed, transmission gear ratio, and tractor specifications, and the gear shift performance of the tractor model according to the number of gears was confirmed. The simulated model thus satisfies the characteristics of the target tractor and can be used to verify the gear shift performance, indicating that the model can verify the performance of the control algorithm in real time.

Agricultural tractors are connected with various implements such as plow, baler, rotovator, and loader for performing agricultural work. In particular, the rotovator is used to crush and uniformly spread the soil after plowing operations. However, achieving uniformly spread soil and flattened fields using rotovator can be extremely challenging, because the soil is often pushed to a particular side or remains on a slope owing to the variations in soil composition, plowing depth, and the skill level of workers, which consequently affects the transplantation work. This study aims to analyze the prediction accuracy of the implement and tractor attitudes as a reference standard by (a) developing an algorithm to predict the implement attitude based on the hitch height, support points of the lower link and lift rod, and distance between the lower links, through four-section link mathematical modeling for a three-point hitch system, and (b) using an observer to predict the tractor attitude using a Kalman filter with gyroscopic and acceleration sensors. We developed a control algorithm using the gyroscopic and acceleration information from the sensor to improve the precision and adjustment speed of the conventional tractor–implement leveling-control system. In addition, the performance improvement was verified by comparing the conventional and proposed systems. The results revealed that the error rates in the proposed system were up to 72% less than those of the conventional system, implying that the control performance of the stated system could be improved by reducing the implement attitude estimation error and tractor attitude measurement delay.

In this study, a semi-active suspension based on a hydro-pneumatic mechanism was designed to minimize the ride vibration using a suspension control algorithm. The performance of the algorithm was critical for controlling the characteristics of the target tractor. A linear-quadratic-Gaussian (LQG) optimal control algorithm was designed as a semi-active suspension control algorithm. The plant model for developing this algorithm was based on the parameters of an actual tractor. The rear suspension deflection was represented by a Kalman-filter-based state observer feedback to estimate the state variables that were difficult to measure. The designed state observer of the LQG controller was validated in terms of an accuracy index. The estimated vertical velocity and acceleration accuracies of the cabin were 83% and 79%, respectively. The performance of the designed controller was validated in terms of a performance index by comparing the performance of a tractor equipped with a rear rubber mount with that of one equipped with a semi-active suspension. The peak and root-mean-square values of the vertical acceleration of the cabin were reduced by up to 48.97% and 47.06%, respectively. This study could serve as a basis for the application of the control algorithm to systems with similar characteristics, thereby reducing system costs.

Abstract In this research, dispersion of a new type of one-dimensional inorganic material Nb2Se9, composed of van der Waals bonds, in aqueous solution for bio-application study were studied. To disperse Nb2Se9, which exhibits hydrophobic properties in water, experiments were carried out using a block copolymer (poloxamer) as a dispersant. It was confirmed that PPO, the hydrophobic portion of Poloxamer, was adsorbed onto the surface of Nb2Se9, and PEO, the hydrophilic portion, induced steric hinderance to disperse Nb2Se9 to a size of 10 nm or less. To confirm the adaptability of muscle cells C2C12 to the dispersed Nb2Se9 using poloxamer 188 as dispersant, a MTT assay and a live/dead assay were performed, demonstrating improvement in the viability and proliferation of C2C12 cells.

Abstract With the increase in high-rise building construction, failure to consider constructability in the design phase can result in huge wastes in the construction phase, as well as losing opportunities for design improvement. However, existing approaches for reflecting constructability rely heavily on reviews, resulting in an inefficient decision-making process. Thus, by considering appropriate timing and detail levels when applying construction knowledge, this study proposes a process for integrating constructability activities related to temporary work into the design phase in high-rise concrete buildings. Through an investigation of information-dependency relationships, 22 constructability activities were linked with 33 design activities. Further, these activities’ implementation processes were constructed based on optimized information flows from a partitioned dependency structure matrix. The results of this study can help a project team address constructability issues at the appropriate time during the design process and will contribute to improving the efficiency of the overall project operation in high-rise building construction.

Objective Patients are often transported within the hospital, especially in cases of critical illness for which computed tomography (CT) is performed. Since increased transport time increases the risks of complications, reducing transport time is important for patient safety. This study aimed to evaluate the ability of our newly invented device, the Easy Tube Arrange Device (ETAD), to reduce transport time for CT evaluation in cases of critical illness. Methods This prospective randomized control study included 60 volunteers. Each participant arranged five or six intravenous fluid lines, monitoring lines (noninvasive blood pressure, electrocardiography, central venous pressure, arterial catheter), and therapeutic equipment (O2 supply device, Foley catheter) on a Resusci Anne mannequin. We measured transport time for the CT evaluation by using conventional and ETAD method. Results The median transport time for CT evaluation was 488.50 seconds (95% confidence interval [CI], 462.75 to 514.75) and, 503.50 seconds (95% CI, 489.50 to 526.75) with 5 and 6 fluid lines using the conventional method and 364.50 seconds (95% CI, 335.00 to 388.75), and 363.50 seconds (95% CI, 331.75 to 377.75) with ETAD (all P

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Background We hypothesized that the direction of the J-tip of the guidewire during insertion into the internal jugular vein (IJV) might determine its ultimate location. Methods In this study, 300 patients between the ages of 18 and 99 years who required central venous catheterization via IJV in the emergency department enrolled for randomization. IVJ catheterization was successful in 285 of 300 patients. An independent operator randomly prefixed the direction of the J-tip of the guidewire to one of three directions. Based on the direction of the J-tip, patients were allocated into three groups: the J-tip medial-directed group (Group A), the lateral-directed group (Group B), or the downward-directed group (Group C). Postoperative chest radiography was performed on all patients in order to visualize the location of the catheter tip. A catheter is considered malpositioned if it is not located in the superior vena cava or right atrium. Results Of the total malpositioned catheter tips (8 of 285; 2.8%), the majority (5 of 8; 62.5%) entered the contralateral subclavian vein, 2 (25.0%) were complicated by looping, and 1 (12.5%) entered the ipsilateral subclavian vein. According to the direction of the J-tip of the guidewire, the incidence of malpositioning of the catheter tip was 4 of 92 in Group A (4.3%), 4 of 96 in Group B (4.2%), and there were no malpositions in Group C. There were no significant differences among the three groups (p = 0.114). Conclusions The direction of the J-tip of the guidewire had no statistically significant effect on incidence of malpositioned tips.

This study was conducted to develop a load-sensitive engine speed control system to maximize the fuel efficiency of an agricultural tractor. The engine speed controller was developed through a model-based design approach using a tractor simulation model. The simulated engine speed and torque values were measured with an average error range of 1.4−4.9% compared to results obtained from field experiments. Using the tractor model, the gain parameters of the proportional−integral (PI) controller were optimized under the step, ramp, and actual load conditions. The simulation results using the actual load showed that the engine speed could be adjusted to within 2−3% of the desired value using the proposed engine speed controller. The throttle control system was constructed using four parts of a tractor engine, a microprocessor with an engine speed control algorithm, a throttle actuator, and a data acquisition system. Using the developed system, the operating engine speed values showed an average 1.17 % error compared to the desired engine speed. Three fuel efficiency parameters were used for evaluating the fuel-saving performance of the control system: specific volumetric fuel consumption (SVFC), fuel consumption per tilled area (FCA), and fuel consumption per work hour (FC). The values for SVFC, FCA, and FC obtained from the engine speed control system during plowing operations were 23.03−57.87%, 4.11−42.06%, and −7.24−38.48%, respectively, showing an improvement over the same operations without the control system.

We propose and demonstrate a selection scheme of lasing direction by imposing a loss imbalance structure into the single mode square ring cavity. The control of the traveling direction is realized by introducing a taper-step section in one of the straight waveguides of the square ring cavity. It was shown by semi-analytic calculation that the taper-step section in the cavity provides effective loss imbalance between two travelling directions as the round trip repeats. Various kinds of square cavities were fabricated using InGaAsP/InGaAs multiple quantum well semiconductor materials in order to test the direction selectivity while maintaining the single mode. We also measured the pump power dependent lasing spectra to investigate the maintenance property of the lasing direction. The experimental results demonstrated that the proposed scheme is an efficient means for a unidirectional lasing in a single mode laser. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adequate airway management plays an important role in high-quality cardiopulmonary resuscitation (CPR). Airway management is usually performed using an endotracheal tube (ETT) during CPR. However, no study has assessed the effect of ETT size on the fl ow rate and airway pressure during CPR. METHODS: We measured changes in peak inspiratory fl ow rate (PIFR), peak airway pressure (Ppeak), and mean airway pressure (Pmean) according to changes in ETT size (internal diameter 6.0, 7.0, and 8.0 mm) and with or without CPR. A tidal volume of 500 mL was supplied at a rate of 10 times per minute using a mechanical ventilator. Chest compressions were maintained at a constant compression depth and speed using a mechanical chest compression device (LUCAS2, mode: active continuous, chest compression rate: 102±2/minute, chest compression depth 2-2.5 inches). RESULTS: The median of several respiratory physiological parameters during CPR was significantly different according to the diameter of each ETT (6.0 vs. 8.0 mm): PIFR (32.1 L/min [30.5-35.3] vs. 28.9 L/min [27.5-30.8], P<0.001), Ppeak (48.84 cmH2O [27.46-52.11] vs. 27.45 cmH2O [22.53-52.57], P<0.001), and Pmean (18.34 cmH2O [14.61-21.66] vs.13.66 cmH2O [8.41-19.24], P<0.001). CONCLUSION: The changes in PIFR, Ppeak, and Pmean were related to the internal diameter of ETT, and these values tended to decrease with an increase in ETT size. Higher airway pressures were measured in the CPR group than in the no CPR group. [ABSTRACT FROM AUTHOR]

The successful construction of tall buildings requires effective construction management based on various quantitative data. The recent development of ubiquitous sensor networks (USNs) enables massive amounts of data to be collected in real-time. However, the application of USN-based data acquisition systems to repetitive tasks on typical floors of tall buildings can be inefficient, because this may involve the repetitive reinstallation of sensors and the repositioning of data loggers and routers to enable continuous data transfer. To minimize this cumbersome work, a modified data acquisition method using reusable sensor nodes and mobile devices can be a useful solution. This study analyzes the economic aspects of the USN-based systems for concrete temperature monitoring by using the activity-based costing technique. The case study shows that the modified system can reduce the process cost by about 19%. It can also reduce the resource input time of management by about 55%, freeing up time for other management activities. Moreover, the cost benefits should scale up as projects increasingly require more measurement and monitoring. This study should facilitate the application of USN-based information management systems, particularly for tall building construction. [ABSTRACT FROM AUTHOR]

Using traps and passive integrated transponder (PIT) telemetry, we investigated the effectiveness of the nature-like fishway installed at Sangju Weir on the Nakdong River, Korea. In 11 regular checks over the study period, 1474 individuals classified into 19 species belonging to 5 families were collected by the traps, representing 66% of the species inhabiting the main channel of the Nakdong River. PIT tags were applied to 1615 individuals belonging to 22 species, revealing fishway attraction and passing rates of 20.7% and 14.5%, respectively. Interspecific differences were also shown. For 63.2% of fishes, it took more than a day to pass through the fishway. Some individuals spent a longer time (>28 days) inside the fishway, suggesting the fishway was also being used for purposes other than passage. In this study, we verified species diversity of fish using a nature-like fishway installed in a large river in Korea. The results of this study provide a useful contribution to the development of fishways suitable for fish species endemic to Korea and for non-salmonid fish species worldwide. [ABSTRACT FROM AUTHOR]

Objectives The aim of this manikin study was to compare the efficiency between overlapping (OP) and adjacent thumb positions (AP) for cardiac compressions using the encircling method in infants. Methods The study conducted from December 2010 to August 2011 involved 48 volunteers who were students in the emergency medical technician course. The authors let volunteers practice OP and AP as a crossover design. The authors monitored the simulated mean arterial pressure (MAP) generated during a 5-min chest compression. The fatigue level of the volunteers after the chest compression was evaluated with the Likert scale. Results There were no significant differences in MAP between the dominant hand and the non-dominant hand as the lower thumb of OP. Significant differences were observed in simulated systolic blood pressure, MAP and simulated pulse pressure between OP and AP at 1, 2, 3, 4 and 5 min. There were no significant differences among the changes in heart rate, respiratory rate and end-tidal CO2 during a 5-min chest compression by OP and AP. The Likert scale scores (1 no fatigue to 5= extreme fatigue) during the 5-min chest compressions were higher in AP than in OP at 2, 3 and 5 min. Conclusion Higher intrathoracic pressures were achieved by OP in this study. However, further studies are needed to validate these effects of overlapping thumbs technique in infant cardiopulmonary resuscitation, not manikin. [ABSTRACT FROM AUTHOR]

BACKGROUND Ablative carbon dioxide (CO2) fractional resurfacing is a promising therapeutic intervention for the treatment of acne scars, although this technique is associated with prolonged surgical site erythema and edema, which may affect the daily lives of patients. Autologous platelet-rich plasma (PRP) is known to enhance wound healing and has applications in many areas of medicine. OBJECTIVES To evaluate the synergistic effects of autologous PRP with CO2 fractional resurfacing for acne scars. MATERIALS AND METHODS A split-face trial was conducted in 14 Korean participants with acne scars. All participants received one session of ablative CO2 fractional resurfacing. Immediately after resurfacing, facial halves were randomly assigned to receive treatment with autologous PRP injections on one side (experimental side) and normal saline injections on the other side (control side). The participants were monitored for degree of recovery and resurfacing-associated adverse events, including prolonged erythema, edema, and other effects on days 0, 2, 4, 6, 8, 15, and 30. The intensity of erythema was objectively measured using a chromometer at the same time intervals. After one additional treatment session using the same protocol, two independent dermatologists evaluated clinical improvement using a quartile grading scale. RESULTS All participants completed the study. Erythema on the experimental side improved faster than on the control side and was significantly less at day 4 (p = .01). This difference was confirmed using a chromometer (p = .049). Total duration of erythema was an average of 10.4±2.7 days on the control side and 8.6±2.0 days on the experimental side (p = .047). Edema also improved faster on the experimental side than on the control side. The total duration of edema was an average of 7.1±1.5 days on the control side and 6.1±1.1 days on the experimental side (p = .04). Participants were also assessed for duration of post-treatment crusting, with a mean of 6.8±1.0 days on the control side and 5.9±1.1 days on the experimental side (p = .04). No other adverse effects were observed in any participant. Four months after the final treatment, overall degree of clinical improvement was significantly better on the experimental side (2.7±0.7) than on the control side (2.3±0.5) (p = .03). CONCLUSIONS Treatment with PRP after ablative CO2 fractional resurfacing enhances recovery of laser-damaged skin and synergistically improves the clinical appearance of acne scarring. [ABSTRACT FROM AUTHOR]

BACKGROUND Wrinkle formation usually accompanies skin aging. Periorbital wrinkles in particular are an early sign of skin aging. Therefore, several modalities have been developed to treat periorbital wrinkles, including topical applications, surgical techniques, and laser resurfacing. The 2,790-nm yttrium scandium gallium garnet (YSGG) laser has been increasing in popularity recently, but there have been no investigations into the use of a 2,790-nm YSGG laser for the treatment of periorbital wrinkles. OBJECTIVE To evaluate the clinical efficacy of a 2,790-nm YSGG laser for treating periorbital wrinkles. MATERIALS AND METHODS Ten Korean patients (Fitzpatrick skin type II–V) with periorbital wrinkles were enrolled in this study. They were treated two times with a 4-week interval using a 2,790-nm YSGG laser. The treatment parameters were an average 2-J/cm2 fluence, 6-mm spot size, and 0.3-ms pulse width. Treatment consisted of two to three passes of the laser with 20% overlap until a clinical end point of mild erythema was observed. Patients were examined 1 week after each treatment and 3 months after the last treatment. Two independent, blinded dermatologists evaluated clinical improvement using the Fitzpatrick Wrinkle Classification System (FWCS) by comparing digital photographs taken before treatment (baseline) and 3 months after the last treatment. Efficacy was assessed by subtracting the baseline score from the score at 3 months after the last treatment (wrinkle improvement<0; no change=0; worsening>0). At each visit, the patients were also evaluated for any side effects. At the end of the study, the patients documented their degree of satisfaction on a scale of very satisfied, satisfied, slightly satisfied, and unsatisfied. RESULTS All patients completed the two treatment sessions, and all experienced clinical improvement of periorbital wrinkles based on the physician assessments. The mean treatment efficacies for the right and left sides using the FWCS were −1.85±0.82 and −1.70±0.71, respectively. Nine of 10 participants were satisfied with the procedure. Transient hyperpigmentation and slight exfoliation were observed in one patient after the last treatment, but this disappeared within 10 weeks. CONCLUSION In treating periorbital wrinkles, a 2,790-nm YSGG laser treatment might be an effective treatment modality with minimal complications. The authors have indicated no significant interest with commercial supporters. [ABSTRACT FROM AUTHOR]

BACKGROUND Photodynamic therapy (PDT) with aminolevulinic acid or methyl 5-aminolevulinic acid (MAL) has been tried for the treatment of alopecia areata (AA). Unfortunately, the efficacy of PDT in treating AA is still being debated, and most clinical trials have produced disappointing results, which may have been because of the lack of treatment rationale or because of drug penetration. In several clinical trials of PDT in AA, the dermatologists suspected that skin preparations, including mechanical or chemical peeling, might be incomplete for drug penetration. OBJECTIVE In this pilot study, the efficacy of PDT in treating AA was investigated, and the treatment effect of the use of a microneedle roller for the enhancement of the transepidermal drug delivery system was evaluated. MATERIALS AND METHODS Eight Korean patients with alopecia totalis were enrolled in this study. Before the PDT, the right sides of the patients' scalps were prepared using 70% alcohol dressing and microneedle rolling, and the left sides (the control sides, without microneedle rolling) were only cleansed with 70% alcohol dressing. Immediately after the microneedle roller preparation, MAL was applied on the right scalp area under occlusion for 3 hours. Both sides were then illuminated with a red light (average wavelength, 630 nm; light dose, 37 J/cm2) for 7.5 minutes. Each patient received three treatments at 4-week intervals. A photograph of each patient was taken before and after the treatment. Biopsy was performed on the samples that were taken from both sides of the alopecia totalis lesions after 16 weeks (4 weeks after the final treatment). RESULTS After the three treatments, none of the patients achieved hair growth in the microneedle-rolled lesion or in the unrolled lesion. Furthermore, there was no increment in the density of the anagen hair follicles and no difference in the histologic findings of the groups. CONCLUSION PDT with MAL may not be effective for the treatment of alopecia totalis, regardless of the use of a microneedle roller to increase skin penetration. The authors have indicated no significant interest with commercial supporters. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 41-year-old Korean man with a recurrent follicular eruptions on the back and diagnosed with Malassezia folliculitis. It discusses the application of topical photodynamic therapy with methyl aminolevulinate (MAL-PDT) as an alternative treatment for recalcitrant Mallassezia folliculitis. It notes that a decreased in the inflammatory lesions was noted after the patient undergone MAL-PDT. An overview of the history of the disease is also offered.

Cutis verticis gyrata (CVG) is a descriptive term for a scalp condition that is convoluted folds and deep furrows that resemble the surface of the cerebral cortex. It is categorized by the underlying etiology, as primary essential, primary non-essential and secondary. Alopecia areata (AA) is a common, organ specific autoimmune disease, and most AA cases are sporadic. There is clearly a strong genetic component. There is no established relationship between CVG and AA. We report one case which was affected with essential primary CVG and alopecia areata, and suggest a possibility of genetic association between CVG and AA, possibly both being related to mutations in the fibroblast growth factor receptor 2 (FGFR2). [ABSTRACT FROM AUTHOR]

The authors have indicated no significant interest with commercial supporters. [ABSTRACT FROM AUTHOR]

In this study, crank-locker kinematic equations were used to analyze the three-point hitch behavior when the dynamometer was connected to the work machine. The dynamometer was statically tested with a hydraulic actuator, and the accuracy of the three-way force and the moment was confirmed to be 96–99%. The calibrated dynamometer was put to the test on a real farm field, and data were collected using a data acquisition system. Using the transport pitch correction equation, the collected data can be transformed into more realistic data. International standards were used to determine the point of connection between the tractor, dynamometer, and implement. The results of this study made it possible to accurately measure force and moment, which will have an important role in future agricultural technologies such as autonomous agricultural operation.

Research on dual-clutch transmissions in agricultural tractors is on the rise. Dual-clutch transmissions provide a smooth driving experience and easy operation compared to manual transmissions, as they eliminate power interruptions. Accordingly, there is ongoing research to improve the conventional synchronizer pre-selection method. The study introduces a new control strategy to enhance shifting quality by focusing on shift force and timing. Specifically, the goal is to optimize the impact of pre-selection-induced shock and delayed shift time, minimizing discomfort for the driver. According to the experimental results, it was determined that factors influencing the impact of preselect engagement on gear shift shock were absent, while factors capable of affecting shift time were identified in the form of shift force. However, it was concluded that optimizing shift force and shift timing based on the number of shifts can enhance the quality of gear shifting. Even during preselect disengagement, the factor influencing gear shift shock was identified as the shift timing, with no discernible factor affecting shift time. Nevertheless, it was judged that optimizing shift force and shift timing based on the number of shifts can lead to an improvement in gear shifting quality. In conclusion, the control strategy determined through the parameter study is expected to improve the shifting quality of tractors equipped with dual-clutch transmission. These findings have the potential to support efficient and convenient tractor operation in the agricultural sector.

Abstract The current status of 2D organic–inorganic hybrid perovskites for use in photovoltaic (PV) and light-emitting diode (LED) applications lags far behind their 3D counterparts. Here, we propose a computational strategy for discovering novel perovskites with as few computing resources as possible. A tandem optimization algorithm consisting of an elitism-reinforced nondominated sorting genetic algorithm (NSGA-II) and a multiobjective Bayesian optimization (MOBO) algorithm was used for density functional theory (DFT) calculations. The DFT-calculated band gap and effective mass were taken as objective functions to be optimized, and the constituent molecules and elements of a Ruddlesden–Popper (RP) structure (n = 2) were taken as decision variables. Fourteen previously unknown RP perovskite candidates for PV and LED applications were discovered as a result of the NSGA-II/MOBO algorithm. Thereafter, more accurate DFT calculations based on the HSE06 exchange correlation functional and ab initio molecular dynamics (AIMD) were conducted for the discovered 2D perovskites to ensure their validity.

Abstract A tandem (two‐step) particle swarm optimization (PSO) algorithm is implemented in the argyrodite‐based multidimensional composition space for the discovery of an optimal argyrodite composition, i.e., with the highest ionic conductivity (7.78 mS cm−1). To enhance the industrial adaptability, an elaborate pellet preparation procedure is not used. The optimal composition (Li5.5PS4.5Cl0.89Br0.61) is fine‐tuned to enhance its practical viability by incorporating oxygen in a stepwise manner. The final composition (Li5.5PS4.23O0.27Cl0.89Br0.61), which exhibits an ionic conductivity (σion) of 6.70 mS cm−1 and an activation barrier of 0.27 eV, is further characterized by analyzing both its moisture and electrochemical stability. Relative to the other compositions, the exposure of Li5.5PS4.23O0.27Cl0.89Br0.61 to a humid atmosphere results in the least amount of H2S released and a negligible change in structure. The improvement in the interfacial stability between the Li(Ni0.9Co0.05Mn0.05)O2 cathode and Li5.5PS4.23O0.27Cl0.89Br0.61 also results in greater specific capacity during fast charge/discharge. The structural and chemical features of Li5.5PS4.5Cl0.89Br0.61 and Li5.5PS4.23O0.27Cl0.89Br0.61 argyrodites are characterized using synchrotron X‐ray diffraction, Raman spectroscopy, and X‐ray photoelectron spectroscopy. This work presents a novel argyrodite composition with favorably balanced properties while providing broad insights into material discovery methodologies with applications for battery development.

Abstract Predicting mechanical properties such as yield strength (YS) and ultimate tensile strength (UTS) is an intricate undertaking in practice, notwithstanding a plethora of well-established theoretical and empirical models. A data-driven approach should be a fundamental exercise when making YS/UTS predictions. For this study, we collected 16 descriptors (attributes) that implicate the compositional and processing information and the corresponding YS/UTS values for 5473 thermo-mechanically controlled processed (TMCP) steel alloys. We set up an integrated machine-learning (ML) platform consisting of 16 ML algorithms to predict the YS/UTS based on the descriptors. The integrated ML platform involved regularization-based linear regression algorithms, ensemble ML algorithms, and some non-linear ML algorithms. Despite the dirty nature of most real-world industry data, we obtained acceptable holdout dataset test results such as R2 > 0.6 and MSE

Abstract Most data-driven machine learning (ML) approaches established in metallurgy research fields are focused on a build-up of reliable quantitative models that predict a material property from a given set of material conditions. In general, the input feature dimension (the number of material condition variables) is much higher than the output feature dimension (the number of material properties of concern). Rather than such a forward-prediction ML model, it is necessary to develop so-called inverse-design modeling, wherein required material conditions could be deduced from a set of desired material properties. Here we report a novel inverse design strategy that employs two independent approaches: a metaheuristics-assisted inverse reading of conventional forward ML models and an atypical inverse ML model based on a modified variational autoencoder. These two unprecedented approaches were successful and led to overlapped results, from which we pinpointed several novel thermo-mechanically controlled processed (TMCP) steel alloy candidates that were validated by a rule-based thermodynamic calculation tool (Thermo-Calc.). We also suggested a practical protocol to elucidate how to treat engineering data collected from industry, which is not prepared as independent and identically distributed (IID) random data.

Identifying the composition of multiphase inorganic compounds from XRD patterns is challenging. Here the authors use a convolutional neural network to identify phases in unknown multiphase mixed inorganic powder samples with an accuracy of nearly 90%.

Abstract The prediction of macro‐scale materials properties from microstructures, and vice versa, should be a key part in modeling quantitative microstructure‐physical property relationships. It would be helpful if the microstructural input and output were in the form of visual images rather than parameterized descriptors. However, only a typical supervised learning technique would be insufficient to build up a model with real‐image‐output. A generative adversarial network (GAN) is required to treat visual images as output for a promising PMPR model. Recently developed deep‐learning‐based GAN techniques such as a deep convolutional GAN (DCGAN), a cycle‐consistent GAN (Cycle GAN), and a conditional GAN‐based image to image translation (Pix2Pix) could be of great help via the creation of realistic microstructures. In this regard, we generated virtual micrographs for various types of steels using a DCGAN, a Cycle GAN, and a Pix2Pix and confirmed the generated micrographs are qualitatively indistinguishable from the ground truth.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.