Applied Sciences

Advanced air mobility (AAM) is a broad concept enabling consumers access to on-demand air mobility, cargo and package delivery, healthcare applications, and emergency services through an integrated and connected multimodal transportation network. While a number of technical and social concerns have been raised about AAM, early use cases for emergency response and aeromedical transport may be key to demonstrating the concept and building public acceptance. Using a five-step multi-method approach consisting of preliminary scoping, modeling performance metrics, developing baseline assumptions, analyzing scenarios, and applying a Monte Carlo sensitivity analysis, this study examines the potential operational and market viability of the air ambulance market using a variety of aircraft and propulsion types. The analysis concludes that electric vertical take-off and land (eVTOL) aircraft could confront a number of operational and economic challenges for aeromedical applications compared to hybrid vertical take-off and land (VTOL) aircraft and rotorcraft. The study finds that technological improvements such as reduced charge times, increased operational range, and battery swapping could make the eVTOL aircraft more reliable and cost-effective for aeromedical transport. Full article

In recent years, more and more attention has been paid to text sentiment analysis, which has gradually become a research hotspot in information extraction, data mining, Natural Language Processing (NLP), and other fields. With the gradual popularization of the Internet, sentiment analysis of Uyghur texts has great research and application value in online public opinion. For low-resource languages, most state-of-the-art systems require tens of thousands of annotated sentences to get high performance. However, there is minimal annotated data available about Uyghur sentiment analysis tasks. There are also specificities in each task—differences in words and word order across languages make it a challenging problem. In this paper, we present an effective solution to providing a meaningful and easy-to-use feature extractor for sentiment analysis tasks: using the pre-trained language model with BiLSTM layer. Firstly, data augmentation is carried out by AEDA (An Easier Data Augmentation), and the augmented dataset is constructed to improve the performance of text classification tasks. Then, a pretraining model LaBSE is used to encode the input data. Then, BiLSTM is used to learn more context information. Finally, the validity of the model is verified via two categories datasets for sentiment analysis and five categories datasets for emotion analysis. We evaluated our approach on two datasets, which showed wonderful performance compared to some strong baselines. We close with an overview of the resources for sentiment analysis tasks and some of the open research questions. Therefore, we propose a combined deep learning and cross-language pretraining model for two low resource expectations. Full article

This paper demonstrates the possibility of creating oxygen deficiency in perovskites A⁺³B⁺³O₃ by introducing two types of cations with different charges into the B-sublattice. For this, it is proposed to introduce a two-charged cation, for example, Zn²⁺, as an alternative to alkaline earth metals. Previously, this possibility was demonstrated for aluminate LaAlO₃ and indate LaInO₃. In this article, we have focused on the modification of the scandium-containing perovskite LaScO₃. The novel oxygen-deficient perovskite La₂ScZnO_5.5 and doped phases La_1.9Ca_0.1ScZnO_5.45, La₂Sc_0.9Ca_0.1ZnO_5.45, and La₂Sc_0.9Mg_0.1ZnO_5.45 were obtained via a solid-state reaction process. Their phase composition and hydration were investigated by XRD and TGA + MS techniques. The conductivities of these materials were measured by the electrochemical impedance technique under atmospheres of various water vapor partial pressures. All phases crystallized in orthorhombic symmetry with the Pnma space group. The phases were capable of reversible water uptake; the proton concentration increased in the order of La₂ScZnO_5.5 < La₂Sc_0.9Mg_0.1ZnO_5.45 < La₂Sc_0.9Ca_0.1ZnO_5.45 ≈ La_1.9Ca_0.1ScZnO_5.45 and reached ~90% hydration limit for Ca²⁺-doped phases. The total conductivities increased with the increase in the free lattice volume in the sequence of σLa₂ScZnO_5.5 < σLa₂Sc_0.9Mg_0.1ZnO_5.45 < σLa_1.9Ca_0.1ScZnO_5.45 < σLa₂Sc_0.9Ca_0.1ZnO_5.45, the activation energy decreased in the same sequence. The sample La₂Sc_0.9Ca_0.1ZnO_5.45 showed the highest conductivity of about 10⁻³ S∙cm⁻¹ at 650 °C (dry air pH₂O = 3.5·10⁻⁵ atm). Water incorporation was accompanied by an increase in conductivity in wet air (pH₂O = 2·10⁻² atm) due to the appearance of proton conductivity. The sample La₂Sc_0.9Ca_0.1ZnO_5.45 showed a conductivity of about 10⁻⁵ S∙cm⁻¹ at 350 °C (pH₂O = 2·10⁻² atm). A comparison of conductivities of obtained phase La₂ScZnO_5.5 with the conductivities of La₂AlZnO_5.5 and La₂InZnO_5.5 was made; the nature of the B-cation did not significantly affect the total conductivity. Full article

The formation of the shear band is associated with the failure of soil. However, there has been relatively little investigation on the evolution of shear bands in naturally structured clay with a high sensitivity. In this study, undrained plane strain compression tests, digital image correlation (DIC) analyses, and scanning electron microscopy (SEM) tests were performed to investigate the characteristics of shear bands in naturally structured clay. The basic mechanical properties and stress–strain relationships show that naturally structured clay exhibits a strong structure and high sensitivity. Compared with plane strain compression tests under low confining pressure, more localized shear bands emerge in the specimens during the tests under high confining pressures; however, when the specimens fail, only one shear band is fully developed, and the local deformation in the developed shear band is much larger than those in other localized shear bands. Moreover, the local stress–strain relationships inside and outside the shear band show distinct discrepancies. The SEM results show distinct micro-structures of clays inside and outside the shear band, which are caused by the development of the shear band. The findings in this work provide new insight into the failure of structured clay. Full article

Downdraft gasification is a promising process of energy conversion of wood biomass. There are such fuel conversion conditions that differ favorably from conventional conditions. In such conditions, there is no pyrolysis zone in the fuel bed, which precedes the oxidation zone. Fuel is supplied into the oxidizing zone without charring, where it reacts with the intensive cold air flow from tuyeres. The study aims to replicate the conversion of particles in a gasifier close to tuyeres. For this purpose, the individual particles are burned in the muffle furnace space and the quartz channel replicating presence of other bed particles at a first approximation. In the experiment, the furnace temperature was varied, as well as the velocity of air supplied to the particle. Two-stage and single-stage mechanisms of particle combustion were identified. A two-stage process is observed in the range of tuyere velocities below 20 m s⁻¹. The two-stage mechanism is characterized by a stage of devolatilization and volatiles combustion, followed by a stage of char residue combustion. The stages are predominantly separate from each other, and their degree of overlapping is low, amounting to 24%. At the tuyere velocities above 125 m s⁻¹ combustion of particles is realized primarily as a single-stage process. The intensive air flow reaches the fuel particle surface and initiates combustion of the surface char layer. In this case, the stages of devolatilization and char residue combustion run concurrently for the most part. In the single-stage mechanism, the degree of stage overlapping is significantly higher and amounts to 60–95%. For the two-stage combustion mechanism, the effect of cyclic movement of the flame across the particle surface is evident. The number of cycles can reach eight. This effect is due to the change of conversion stages. At air velocity above 95 m s⁻¹, fragmentation of fuel particles commences. A layer of char formed at an initial stage of burning heats up in the intensive air flow and is separated from the particle surface. The heated walls of the quartz channel contribute to the intensification of particle combustion. This effect is probably due to the swirling of the flame between the wall and the particle surface. Full article

In this paper, a portable exoskeleton for the rehabilitation of upper extremities of three degrees of freedom (DOF) is proposed. With these degrees of freedom, the exoskeleton provides the movements of flexion–extension and abduction–adduction of the arm and flexion–extension of the forearm. A robust generalized proportional integral (GPI) controller for trajectory tracking to provide smooth movements for rehabilitation with the exoskeleton is proposed. This controller only requires output measurements and is robust against different types of disturbances. Simulation results are presented in the MSC Adams^® software environment in co-simulation with Matlab-Simulink^® to show the controller’s performance against different types of disturbances. The results of a PID type controller are also contrasted with the results of the GPI controller. Full article

Esca disease is one of the most important grapevine trunk diseases. It seriously reduces the quality and quantity of grapevine production, and results in a shorter vineyard lifespan. Previous studies have suggested that wide xylem vessel diameter favours development on grapevine of Phaeomoniella chlamydospora, one of the fungi involved in esca, thus affecting disease susceptibility. In this study, cultivars mainly originated from European countries, 27 white-berried and 24 red-berried grapevine cultivars, were grown in the same experimental vineyard and were analysed for xylem vessel sizes (as diameter and frequency) for correlation with esca incidence. In this study, the cultivars showed significant differences in the xylem vessel parameters. However, no relationship was detected between vessel size and esca incidence in the field. Overall, white-berried cultivars showed wider vessel diameters than red-berried cultivars. The relationship between xylem vessel size in the red-berried and white-berried cultivars and incidence of esca symptoms is discussed. We suggest that vessel anatomy profiles can provide useful information for further investigations on grapevine genotype structure–esca incidence relationships. Full article

K_xMnO₂ materials with birnessite-type structure are synthetized by two different methods which make it possible to obtain manganese oxides with different degrees of crystallinity. The XPS results indicate that the sample obtained at high temperature (KMn8) exhibits a lower oxidation state for manganese ions as well as a denser morphology. Both characteristics could explain the lower capacity value obtained for this electrode. In contrast, the sample obtained at low temperature (KMn4) or by hydrothermal method presents a manganese oxidation state close to 4 and a more porous morphology. Indeed, in this case higher capacity values are obtained. At current density of 30 mA g⁻¹, the KMn8, KMn4, and HKMn samples display a capacity retention of 88, 82, and 68%, respectively. The higher capacity loss obtained for the HKMn compound could be explained considering that the incorporation of Zn²⁺ in the structure gives rise to the stabilization of a ZnMn₂O₄ spinel-type phase. This compound is obtained in the discharge process but remains in the charge stage. Thus, when this spinel-type phase is obtained the capacity loss increases. Moreover, the stabilization of this phase is more favorable at low current rates where 100% of retention for all samples, before 50 cycles, was observed. Full article

Computational color constancy (CCC) is to endow computers or cameras with the capability to remove the color bias effect caused by different scene illuminations. The first procedure of CCC is illuminant estimation, i.e., to calculate the illuminant color for a given image scene. Recently, some methods directly mapping image features to illuminant estimation provide an effective and robust solution for this issue. Nevertheless, due to diverse image features, it is uncertain to select which features to model illuminant color. In this research, a series of artificial features weaved into a mapping-based illuminant estimation framework is extensively investigated. This framework employs a multi-model structure and integrates the functions of kernel-based fuzzy c-means (KFCM) clustering, non-negative least square regression (NLSR), and fuzzy weighting. By comparing the resulting performance of different features, the features more correlated to illuminant estimation are found in the candidate feature set. Furthermore, the composite features are designed to achieve the outstanding performances of illuminant estimation. Extensive experiments are performed on typical benchmark datasets and the effectiveness of the proposed method has been validated. The proposed method makes illuminant estimation an explicit transformation of suitable image features with regressed and fuzzy weights, which has significant potential for both competing performances and fast implementation against state-of-the-art methods. Full article

High-early strength fiber-reinforced concretes are effective materials for the full depth repair of rigid highway and airfield pavements. A comprehensive study was carried out on the influence of the amount of steel anchor fiber and hardening accelerator on properties that are important for repairing concrete. A two-factor experiment was carried out, in which the influence of the hardening accelerator and fiber dosages on the strength, frost resistance, wear resistance and shrinkage of repaired steel-fiber-reinforced concrete for rigid pavements was studied. The investigated concretes contained 400 kg/m³ of cement and polycarboxylate plasticizer in the amount of 1.2% of the cement content. It has been established that the optimal concrete compositions are with the amount of Sika Rapid 3 hardening accelerator from 1 to 2% of the cement content and the steel fiber amount from 60 to 90 kg/m³. Optimal fiber-reinforced concrete compositions have a reduced shrinkage during hardening, and at the age of 2 days they have a compressive strength of at least 55 MPa and a flexural strength of at least 8.5 MPa. At the design age, the fiber-reinforced concrete compressive strength is 85–90 MPa, its flexural strength ranges from 15.5 to 17.5 MPa, it has a frost resistance of F200 and abrasion not higher than 0.24 g/cm². These properties ensure the high durability of the repair material. Full article

Conventionally, aerial manipulators, when used for inspection, use drone rotors to stabilize the center of gravity (CoG) shifts, which highly affects its performance. This paper discusses the development of a self-balancing lightweight cable aerial manipulator that can be used for construction inspection purposes. The design is based on a 3D-printed, three degrees of freedom (DoF), planar cable manipulator that is mounted on an extended platform below it as a counter-balance mechanism. The actuators control the manipulator links through a cable system, allowing them to be mounted at the system base to reduce the moving mass of the manipulator during operation. The counter-balance mechanism compensates for any shifts in the CoG of the system by actively sliding a counter-balance weight, mainly a battery, which powers the setup. This mechanism can be attached beneath an off-the-shelf quadrotor to solve the problem of CoG shifts. CoG shifts are due to the manipulator operation when a payload or inspection tool is attached to the end effector to perform a given task. For construction integrity inspection, the aerial manipulator must remain stable during the push or slide processes on both flat and curved surfaces while the non-destructive tests are carried out. To validate the effectiveness of the proposed design, an experimental setup was used, and comparisons were made between the compensated and uncompensated tilt angles of the aerial manipulator. Significant tilt angle reductions were observed with an average of 94.69% improvement, undergoing different manipulator motions during different operation scenarios, as a result of an active compensation of the CoG shift and lightweight design of the system, without sacrificing the functionality of the manipulator for the task. Full article

The virtual world has long been a focus not only of the gaming sphere, but also of the manufacturing and educational industries. The virtual world and its technology have many advantages, the basic ones being, for example, the use of experiential learning, with which the human brain can remember some things better and faster. It was due to the advantages of virtual reality technology that we decided to create an educational system on safety and health at work, and we focused on the healthcare segment due to the COVID-19 pandemic. Thanks to the cooperation of a professional consortium, we created an educational system for safety and health at work and carried out several extensive laboratory measurements, the results of which we followed up in practical measurements with medical staff. The created system is inherently unique and applicable and can be used across several industries. The article presents three basic types of scenarios as well as an evaluation of satisfaction with the proposed system from test participants, i.e., nurses. Full article

A brake disc decelerates the vehicle through friction with the brake pads. When the brake system is overheated, brake fade can occur, in which the friction coefficient drops significantly. Additionally, an over-heated brake system may cause vapor lock, in which the brake hydraulic fluid is vaporized. These phenomena can lead to the loss of braking power and cause a fatal accident. Therefore, brake systems must have stable braking and heat dissipation performance. Having through-holes and slits on the friction surface of the rotor has been adopted to improve the heat dissipation performance, but the holes become stress points and potentially cause cracks. Therefore, brake systems should be designed to have structural stability as well as good heat dissipation. In this study, finite element (FE) modeling was developed to analyze the structural stability and heat dissipation performance of a brake system, and structural and thermal simulations were performed in ANSYS, a CAE software package. In addition, to minimize concentrated stress and temperature, optimal design of the shape and pattern of holes and slits was carried out using PIAnO, an integrated optimal design software package. The first step of design optimization was performed while considering the shape and pattern of the disc holes and slits as design factors. Among the design factors, those with the largest effects on the objective functions were found and set as new design factors to perform the second step. The designs were compared to existing discs. Through the optimization presented in this paper, it is expected that the performance of the braking system will improve and the life of the brake parts will be increased. Full article

Image fusion of satellite sensors can generate a high-resolution multi-spectral image from inputs of a high spatial resolution panchromatic image and a low spatial resolution multi-spectral image for feature extraction and target recognition, such as enclosure seines and floating rafts. However, there is currently no clear and definite method of image fusion for different aquaculture areas distribution extraction from high-resolution satellite images. This study uses three types of high-resolution remote sensing images, GF-1 (Gaofen-1), GF-2 (Gaofen-2), and WV-2 (WorldView-2), covering the raft and enclosure seines aquacultures in the Xiangshan Bay, China, to evaluate panchromatic and multispectral image fusion techniques to determine which is the best. This study applied PCA (principal component analysis), GS (Gram–Schmidt), and NNDiffuse (nearest neighbor diffusion) algorithms to panchromatic and multispectral images fusion of GF-1, GF-2, and WV-2. Two quantitative methods are used to evaluate the fusion effect. The first used seven statistical parameters, including gray mean value, standard deviation, information entropy, average gradient, correlation coefficient, deviation index, and spectral distortion. The second is the CQ_max index. Comparing the evaluation results by these seven common statistical indicators with the results of the image fusion evaluation by index CQ_max, the results prove that the CQ_max index can be applied to the evaluation of image fusion effects in different aquaculture areas. For the floating raft cultured area, the conclusion is consentaneous; NNDiffuse was also optimal for GF-1 and GF-2 data, and PCA was optimal for WV-2 data. For the enclosure seines culture area, the conclusion of quantitative evaluations is not consistent and it shows that there is no definite good method that can be applied to all areas; therefore, careful evaluation and selection of the best applicable image fusion method are required according to the study area and sensor images. Full article

In this article, we propose a novel model for facial micro-expression (FME) recognition. The proposed model basically comprises a transformer, which is recently used for computer vision and has never been used for FME recognition. A transformer requires a huge amount of data compared to a convolution neural network. Then, we use motion features, such as optical flow and late fusion to complement the lack of FME dataset. The proposed method was verified and evaluated using the SMIC and CASME II datasets. Our approach achieved state-of-the-art (SOTA) performance of 0.7447 and 73.17% in SMIC in terms of unweighted F1 score (UF1) and accuracy (Acc.), respectively, which are 0.31 and 1.8% higher than previous SOTA. Furthermore, UF1 of 0.7106 and Acc. of 70.68% were shown in the CASME II experiment, which are comparable with SOTA. Full article

Multi-access edge computing (MEC) has emerged as a promising technology to facilitate efficient vehicular applications, such as autonomous driving, path planning and navigation. By offloading tasks from vehicles to MEC servers (MECSs), the MEC system can facilitate computation-intensive applications with hard latency constraints in vehicles with limited computing resources. However, owing to the mobility of vehicles, the vehicles are not evenly distributed across the MEC system. Therefore, some MECSs are heavily congested, whereas others are lightly loaded. If a task is offloaded to a congested MECS, it can be blocked or have high latency. Moreover, service interruption would occur because of the high mobility and limited coverage of the MECS. In this paper, we assume that the task can be divided into a set of subtasks and computed by multiple MECSs in parallel. Therefore, we propose a method of task migration with partitioning. To balance loads, the MEC system migrates the set of subtasks of tasks in an overloaded MECS to one or more underloaded MECSs according to the load difference. Simulations have indicated that, compared with conventional methods, the proposed method can increase the satisfaction of quality-of-service requirements, such as low latency, service reliability, and MEC system throughput by optimizing load balancing and task partitioning. Full article

In this paper, we propose a novel algorithm called multiview temporal alignment by dependence maximisation in the latent space (TRANSIENCE) for the alignment of time series consisting of sequences of feature vectors with different length and dimensionality of the feature vectors. The proposed algorithm, which is based on the theory of multiview learning, can be seen as an extension of the well-known dynamic time warping (DTW) algorithm but, as mentioned, it allows the sequences to have different dimensionalities. Our algorithm attempts to find an optimal temporal alignment between pairs of nonaligned sequences by first projecting their feature vectors into a common latent space where both views are maximally similar. To do this, powerful, nonlinear deep neural network (DNN) models are employed. Then, the resulting sequences of embedding vectors are aligned using DTW. Finally, the alignment paths obtained in the previous step are applied to the original sequences to align them. In the paper, we explore several variants of the algorithm that mainly differ in the way the DNNs are trained. We evaluated the proposed algorithm on a articulatory-to-acoustic (A2A) synthesis task involving the generation of audible speech from motion data captured from the lips and tongue of healthy speakers using a technique known as permanent magnet articulography (PMA). In this task, our algorithm is applied during the training stage to align pairs of nonaligned speech and PMA recordings that are later used to train DNNs able to synthesis speech from PMA data. Our results show the quality of speech generated in the nonaligned scenario is comparable to that obtained in the parallel scenario. Full article

The power generation capability of an electromagnetic vibration energy harvester augmented with an additional coil was investigated and compared with that of a standard single coil electromagnetic energy harvester. A single degree of freedom model and the corresponding equivalent electric circuit were employed for the analysis of the standard and of the augmented harvesters. The harvester model was validated by means of an accurate experimental characterization of a commercial electromagnetic harvester, i.e., the model-D by ReVibe. The electric circuits for the standard and for the augmented harvesters were implemented by electronic components and experimentally tested to determine the maximum power they are able to generate in four test conditions. Results from simulations and from experiments showed significant improvement of the power extraction performance exhibited by the double coil energy harvester, particularly at frequencies lower than the harvester mechanical resonance frequency. Full article

The aim of this study was to assess the skeletal and dentoalveolar effects induced by the Paolone-Kaitsas functional appliance (PK appliance) in the treatment of growing patients affected by Class II malocclusion. A group of 25 Class II patients, treated with the PK appliance followed by fixed appliances, was evaluated with lateral cephalograms at the start (9.6 ± 1.6 years) and at the end of treatment (13.0 ± 1.5 years), and was compared with a matched untreated Class II control group of 23 subjects selected from the web archive of the American Association of Orthodontists Foundation Craniofacial Growth Legacy. Statistical comparisons were performed with the Student’s t-tests. The treated group showed a significant decrease in SNA (−2.2°), ANB (−2.2°), and Wits appraisal (−3.4 mm), a significant increase in the SN-palatal plane angle (1.1°), and a significant improvement in overjet (−2.9 mm), overbite (−2.5 mm), and molar relationship (3.6 mm). The PK appliance produced favorable dentoalveolar and skeletal effects: it inhibited maxillary growth without effects on the mandible and it also induced a downward inclination of the palatal plane. Full article