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Appl. Sci., Volume 9, Issue 20 (October-2 2019)

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Open AccessEditorial
Special Issue on New Industry 4.0 Advances in Industrial IoT and Visual Computing for Manufacturing Processes
Appl. Sci. 2019, 9(20), 4323; https://doi.org/10.3390/app9204323 (registering DOI) - 14 Oct 2019
Abstract
The new advances of IIOT (Industrial Internet of Things), together with the progress in visual computing technologies, are being addressed by the research community with interesting approaches and results in the Industry 4.0 domain[...] Full article
Open AccessArticle
Experimental Study on a Prediction Model of the Shrinkage and Creep of Recycled Aggregate Concrete
Appl. Sci. 2019, 9(20), 4322; https://doi.org/10.3390/app9204322 (registering DOI) - 14 Oct 2019
Abstract
The significant difference between recycled aggregate and natural aggregate is the content of the attached mortar layer. With the increase of the replacement rate of recycled aggregate, the shrinkage and creep of recycled aggregate concrete is significantly increased. In this paper, 180-day shrinkage [...] Read more.
The significant difference between recycled aggregate and natural aggregate is the content of the attached mortar layer. With the increase of the replacement rate of recycled aggregate, the shrinkage and creep of recycled aggregate concrete is significantly increased. In this paper, 180-day shrinkage and creep tests of recycled aggregate concrete with different water–cement ratios were designed in order to analyze the effect of the substitution rate and water–cement ratio on shrinkage and creep properties. The results show that the shrinkage strain of recycled aggregate concrete with a substitution rate of 50% and 100% at 180 days is 26% and 48% higher than that of ordinary concrete, respectively, and the growth of group II is 22% and 47%, respectively. When the load was 180 days old, the creep coefficient of recycled aggregate concrete with a substitution rate of 50% and 100% in group I increased by 19.6% and 39.6%, respectively compared with ordinary concrete, and group II increased by 23.6% and 44.3%, respectively. Based on the difference of adhering mortar content, the creeping increase coefficient and shrinkage increase coefficient of the attached mortar were proposed, and a shrinkage and creep model of recycled aggregate concrete was established. When compared with the experimental results, the model calculation results met the accuracy requirements. Full article
(This article belongs to the Special Issue Green Concrete for a Better Sustainable Environment)
Open AccessArticle
Recovery and Elimination of Phenolic Pollutants from Water Using [NTf2] and [Nf2]-Based Ionic Liquids
Appl. Sci. 2019, 9(20), 4321; https://doi.org/10.3390/app9204321 (registering DOI) - 14 Oct 2019
Abstract
At present, pollution is one of the most important problems worldwide. Industrial growth makes it necessary to develop techniques to remove pollutant substances from water, since water is an important natural source for life. One of these techniques is liquid–liquid extraction, which is [...] Read more.
At present, pollution is one of the most important problems worldwide. Industrial growth makes it necessary to develop techniques to remove pollutant substances from water, since water is an important natural source for life. One of these techniques is liquid–liquid extraction, which is used to remove phenolic compounds from wastewaters. Volatile organic compounds are used as common extraction solvents in liquid–liquid extractions; nevertheless, some of their properties, such as toxicity and volatility, make it necessary to replace them with other less toxic solvents. In this work, the capability of four ionic liquids, based on bis(trifluoromethylsulfonyl)imide [NTf2] and bis(fluorosulfonyl)imide [Nf2] anions and different cations to remove phenolic compounds from water was studied. The phenolic compounds used in this study were phenol, o-cresol, and 2-chlorophenol, and the effects of the extraction solvent and phenol structures were analyzed. For that, a liquid–liquid extraction was carried out, and the extraction yield was determined. In general, high extraction efficiencies were obtained for all studied systems, obtaining the highest extraction efficiencies using the pyrrolidinium cation-based ionic liquids. Full article
(This article belongs to the Special Issue Recent Advances in Water Analysis and Wastewater Treatment)
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Open AccessArticle
Light-Weighted Password-Based Multi-Group Authenticated Key Agreement for Wireless Sensor Networks
Appl. Sci. 2019, 9(20), 4320; https://doi.org/10.3390/app9204320 (registering DOI) - 14 Oct 2019
Abstract
Security is a critical issue for medical and health care systems. Password-based group-authenticated key agreement for wireless sensor networks (WSNs) allows a group of sensor nodes to negotiate a common session key by using password authentication and to establish a secure channel by [...] Read more.
Security is a critical issue for medical and health care systems. Password-based group-authenticated key agreement for wireless sensor networks (WSNs) allows a group of sensor nodes to negotiate a common session key by using password authentication and to establish a secure channel by this session key. Many group key agreement protocols use the public key infrastructure, modular exponential computations on an elliptic curve to provide high security, and thus increase sensor nodes’ overhead and require extra equipment for storing long-term secret keys. This work develops a novel group key agreement protocol using password authentication for WSNs, which is based on extended chaotic maps and does not require time-consuming modular exponential computations or scalar multiplications on an elliptic curve. Additionally, the proposed protocol is suitable for multiple independent groups and ensures that the real identities of group members cannot be revealed. The proposed protocol is not only more secure than related group key agreement protocols but also more efficient. Full article
(This article belongs to the Special Issue Big Data Analytics in Healthcare)
Open AccessArticle
Characteristics of Postural Muscle Activity in Response to A Motor-Motor Task in Elderly
Appl. Sci. 2019, 9(20), 4319; https://doi.org/10.3390/app9204319 (registering DOI) - 14 Oct 2019
Abstract
The purpose of the current study was to evaluate postural muscle performance of older adults in response to a combination of two motor tasks perturbations. Fifteen older participants were instructed to perform a pushing task as an upper limb perturbation while standing on [...] Read more.
The purpose of the current study was to evaluate postural muscle performance of older adults in response to a combination of two motor tasks perturbations. Fifteen older participants were instructed to perform a pushing task as an upper limb perturbation while standing on a fixed or sliding board as a lower limb perturbation. Postural responses were characterized by onsets and magnitudes of muscle activities as well as onsets of segment movements. The sliding board did not affect the onset timing and sequence of muscle initiations and segment movements. However, significant large muscle activities of tibialis anterior and erector spinae were observed in the sliding condition (p < 0.05). The co-contraction values of the trunk and shank segments were significantly larger in the sliding condition through the studied periods (p < 0.05). Lastly, heavy pushing weight did not change the timing, magnitude, sequence of all studied parameters. Older adults enhanced postural stability by increasing the segment stiffness then started to handle two perturbations. In conclusion, they were able to deal with a dual motor-motor task after having secured their balance but could not make corresponding adjustments to the level of the perturbation difficulty. Full article
(This article belongs to the Special Issue Movement Biomechanics and Motor Control)
Open AccessArticle
An Integrated Approach Supporting Remediation of an Aquifer Contaminated with Chlorinated Solvents by a Combination of Adsorption and Biodegradation
Appl. Sci. 2019, 9(20), 4318; https://doi.org/10.3390/app9204318 (registering DOI) - 14 Oct 2019
Abstract
Hydrogeological uniqueness and chemical-physical peculiarities guide the contamination dynamics and decontamination mechanisms in the environmental arena. A single composite geodatabase, which integrates geological/hydrological, geophysical, and chemical data, acts as a “cockpit” in the definition of a conceptual model, design of a remediation strategy, [...] Read more.
Hydrogeological uniqueness and chemical-physical peculiarities guide the contamination dynamics and decontamination mechanisms in the environmental arena. A single composite geodatabase, which integrates geological/hydrological, geophysical, and chemical data, acts as a “cockpit” in the definition of a conceptual model, design of a remediation strategy, implementation, near-real-time monitoring, and validation/revision of a pilot test, and monitoring full-scale interventions. The selected remediation strategy involves the creation of "reactive" zones capable of reducing the concentration of chlorinated solvents in groundwater through the combined action of adsorption on micrometric activated carbon, which is injected into the aquifer, and degradation of organic contaminants, stimulating the dechlorinating biological activity by the addition of an electron donor. The technology is verified through a pilot test, to evaluate the possibility of scaling up the process. The results of post-treatment monitoring reveal abatement of the concentration of chlorinated solvents and intense biological dechlorination activity. Achieving the remediation objectives and project closure is based on the integration of multidisciplinary data using a multiscale approach. This research represents the first completed example in European territory of remediation of an aquifer contaminated with chlorinated solvents by a combination of adsorption and biodegradation. Full article
(This article belongs to the Special Issue Sustainable Environmental Restoration Technologies)
Open AccessArticle
Diagnosis and Prediction of Large-For-Gestational-Age Fetus Using the Stacked GeneralizationMethod
Appl. Sci. 2019, 9(20), 4317; https://doi.org/10.3390/app9204317 (registering DOI) - 14 Oct 2019
Abstract
An accurate and efficient Large-for-Gestational-Age (LGA) classification system is
developed to classify a fetus as LGA or non-LGA, which has the potential to assist paediatricians and
experts in establishing a state-of-the-art LGA prognosis process. The performance of the proposed
scheme is validated by [...] Read more.
An accurate and efficient Large-for-Gestational-Age (LGA) classification system is
developed to classify a fetus as LGA or non-LGA, which has the potential to assist paediatricians and
experts in establishing a state-of-the-art LGA prognosis process. The performance of the proposed
scheme is validated by using LGA dataset collected from the National Pre-Pregnancy and Examination
Program of China (2010–2013). A master feature vector is created to establish primarily data
pre-processing, which includes a features’ discretization process and the entertainment of missing
values and data imbalance issues. A principal feature vector is formed using GridSearch-based
Recursive Feature Elimination with Cross-Validation (RFECV) + Information Gain (IG) feature
selection scheme followed by stacking to select, rank, and extract significant features from the LGA
dataset. Based on the proposed scheme, different features subset are identified and provided to
four different machine learning (ML) classifiers. The proposed GridSearch-based RFECV+IG feature
selection scheme with stacking using SVM (linear kernel) best suits the said classification process
followed by SVM (RBF kernel) and LR classifiers. The Decision Tree (DT) classifier is not suggested
because of its low performance. The highest prediction precision, recall, accuracy, Area Under
the Curve (AUC), specificity, and F1 scores of 0.92, 0.87, 0.92, 0.95, 0.95, and 0.89 are achieved
with SVM (linear kernel) classifier using top ten principal features subset, which is, in fact higher
than the baselines methods. Moreover, almost every classification scheme best performed with ten
principal feature subsets. Therefore, the proposed scheme has the potential to establish an efficient
LGA prognosis process using gestational parameters, which can assist paediatricians and experts to
improve the health of a newborn using computer aided-diagnostic system. Full article
(This article belongs to the Special Issue Innovative Applications of Big Data and Cloud Computing)
Open AccessReview
A Review on Bitumen Rejuvenation: Mechanisms, Materials, Methods and Perspectives
Appl. Sci. 2019, 9(20), 4316; https://doi.org/10.3390/app9204316 (registering DOI) - 14 Oct 2019
Abstract
This review aims to explore the state of the knowledge and the state-of-the-art regarding bitumen rejuvenation. In particular, attention was paid to clear things up about the rejuvenator mechanism of action. Frequently, the terms rejuvenator and flux oil, or oil (i.e., softening agent) [...] Read more.
This review aims to explore the state of the knowledge and the state-of-the-art regarding bitumen rejuvenation. In particular, attention was paid to clear things up about the rejuvenator mechanism of action. Frequently, the terms rejuvenator and flux oil, or oil (i.e., softening agent) are used as if they were synonymous. According to our knowledge, these two terms refer to substances producing different modifications to the aged bitumen: they can decrease the viscosity (softening agents), or, in addition to this, restore the original microstructure (real rejuvenators). In order to deal with the argument in its entirety, the bitumen is investigated in terms of chemical structure and microstructural features. Proper investigating tools are, therefore, needed to distinguish the different mechanisms of action of the various types of bitumen, so attention is focused on recent research and the use of different investigation techniques to distinguish between various additives. Methods based on organic synthesis can also be used to prepare ad-hoc rejuvenating molecules with higher performances. The interplay of chemical interaction, structural changes and overall effect of the additive is then presented in terms of the modern concepts of complex systems, which furnishes valid arguments to suggest X-ray scattering and Nuclear Magnetic Resonance relaxometry experiments as vanguard and forefront tools to study bitumen. Far from being a standard review, this work represents a critical analysis of the state-of-the-art taking into account for the molecular basis at the origin of the observed behavior. Furnishing a novel viewpoint for the study of bitumen based on the concepts of the complex systems in physics, it constitutes a novel approach for the study of these systems. Full article
(This article belongs to the Special Issue Asphalt Materials)
Open AccessArticle
Coordinated Formation Design of Multi-Robot Systems Via an Adaptive-Gain Super-Twisting Sliding Mode Method
Appl. Sci. 2019, 9(20), 4315; https://doi.org/10.3390/app9204315 (registering DOI) - 14 Oct 2019
Abstract
This paper presents a super-twisting-based sliding mode control method for the formation problem of multi-robot systems. The multiple robots contain plenty of uncertainties and disturbances. Such a control method has two adaptive gains that can contribute to the robustness and improve the response [...] Read more.
This paper presents a super-twisting-based sliding mode control method for the formation problem of multi-robot systems. The multiple robots contain plenty of uncertainties and disturbances. Such a control method has two adaptive gains that can contribute to the robustness and improve the response of the formation maneuvers despite these uncertainties and disturbances. Based on the leader-follower frame, this control method was investigated. The closed-loop formation stability is theoretically guaranteed in the sense of Lyapunov. From the aspect of practice, the control method was carried out by a multi-robot system to achieve some desired formation patterns. Some numerical results were demonstrated to verify the feasibility of the control method. Some comparisons were also illustrated to support the superiority and effectiveness of the presented sliding mode control method. Full article
(This article belongs to the Special Issue Multi-Agent Systems 2020)
Open AccessArticle
Synthesis of Novel Heteroatom-Doped Porous-Organic Polymers as Environmentally Efficient Media for Carbon Dioxide Storage
Appl. Sci. 2019, 9(20), 4314; https://doi.org/10.3390/app9204314 (registering DOI) - 14 Oct 2019
Abstract
The high carbon dioxide emission levels due to the increased consumption of fossil fuels has led to various environmental problems. Efficient strategies for the capture and storage of greenhouse gases, such as carbon dioxide are crucial in reducing their concentrations in the environment. [...] Read more.
The high carbon dioxide emission levels due to the increased consumption of fossil fuels has led to various environmental problems. Efficient strategies for the capture and storage of greenhouse gases, such as carbon dioxide are crucial in reducing their concentrations in the environment. Considering this, herein, three novel heteroatom-doped porous-organic polymers (POPs) containing phosphate units were synthesized in high yields from the coupling reactions of phosphate esters and 1,4-diaminobenzene (three mole equivalents) in boiling ethanol using a simple, efficient, and general procedure. The structures and physicochemical properties of the synthesized POPs were established using various techniques. Field emission scanning electron microscopy (FESEM) images showed that the surface morphologies of the synthesized POPs were similar to coral reefs. They had grooved networks, long range periodic macropores, amorphous surfaces, and a high surface area (SBET = 82.71–213.54 m2/g). Most importantly, they had considerable carbon dioxide storage capacity, particularly at high pressure. The carbon dioxide uptake at 323 K and 40 bar for one of the POPs was as high as 1.42 mmol/g (6.00 wt %). The high carbon dioxide uptake capacities of these materials were primarily governed by their geometries. The POP containing a meta-phosphate unit leads to the highest CO2 uptake since such geometry provides a highly distorted and extended surface area network compared to other POPs. Full article
(This article belongs to the Special Issue Carbon Capture and Utilization)
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Open AccessArticle
Sustainable Brick Masonry Bond Design and Analysis: An Application of a Decision-Making Technique
Appl. Sci. 2019, 9(20), 4313; https://doi.org/10.3390/app9204313 (registering DOI) - 14 Oct 2019
Abstract
This research intends to explore the sustainable masonry bond formation and interface behaviour of brick masonry bonds with different cement mortar ratios. To test the sustainable behaviour of different brick bonds, different tests were applied to evaluate the performance of the developed five [...] Read more.
This research intends to explore the sustainable masonry bond formation and interface behaviour of brick masonry bonds with different cement mortar ratios. To test the sustainable behaviour of different brick bonds, different tests were applied to evaluate the performance of the developed five brick masonry structures with the help of four mortar ratios. Following that pattern, the methodologies of a prism triplet test, a bond wrench test, a shear bond test and strength tests for brick masonry were applied. The prism triplet test explained the bonding behaviour of mortar by producing a maximum strength (0.21 MPa) with a 1:3 mix ratio, and the minimum strength (0.095 MPa) with a 1:8 mix ratio. The bond wrench test showed a bond strength of maximum 0.0685 MPa with a mortar ratio of 1:3 and a minimum of 0.035 MPa with a mortar ratio of 1:8. The strength tests for masonry structures expressed that compressive strength (0.786 MPa) and flexural strength (0.352 MPa) were found to be at maximum level with a mortar ratio (1:3) with an English bond formation. For predictions of compressive and flexural strength, artificial neural networks (ANNs) were deployed, and successful predictions of these values along with the relationships between different properties of the material, mortar combinations and bond combinations are presented to complete the exploration of the relationship. This pattern can be helpful for the selection of sustainable brick masonry formations for housing development. Full article
(This article belongs to the Special Issue New Trends of Sustainability in Civil Engineering and Architecture)
Open AccessArticle
Monitor Cotton Budding Using SVM and UAV Images
Appl. Sci. 2019, 9(20), 4312; https://doi.org/10.3390/app9204312 (registering DOI) - 14 Oct 2019
Abstract
Monitoring the cotton budding rate is important for growers so that they can replant cotton in a timely fashion at locations at which cotton density is sparse. In this study, a true-color camera was mounted on an unmanned aerial vehicle (UAV) and used [...] Read more.
Monitoring the cotton budding rate is important for growers so that they can replant cotton in a timely fashion at locations at which cotton density is sparse. In this study, a true-color camera was mounted on an unmanned aerial vehicle (UAV) and used to collect images of young cotton plants to estimate the germination of cotton plants. The collected images were preprocessed by stitching them together to obtain the single orthomosaic image. The support-vector machine method and maximum likelihood classification method were conducted to identify the cotton plants in the image. The accuracy evaluation indicated the overall accuracy of the classification for SVM is 96.65% with the Kappa coefficient of 93.99%, while for maximum likelihood classification, the accuracy is 87.85% with a Kappa coefficient of 80.67%. A method based on the morphological characteristics of cotton plants was proposed to identify and count the overlapping cotton plants in this study. The analysis showed that the method can improve the detection accuracy by 6.3% when compared to without it. The validation based on visual interpretation indicated that the method presented an accuracy of 91.13%. The study showed that the minimal resolution of no less than 1.2 cm/pixel in practice for image collection is necessary in order to recognize cotton plants accurately. Full article
(This article belongs to the Special Issue Applications of Remote Image Capture System in Agriculture)
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Open AccessArticle
Separated Phase–Current Controls Using Inverter-Based DGs to Mitigate Effects of Fault Current Contribution from Synchronous DGs on Recloser–Fuse
Appl. Sci. 2019, 9(20), 4311; https://doi.org/10.3390/app9204311 (registering DOI) - 14 Oct 2019
Abstract
Synchronous distributed generators (SDGs) significantly affect recloser–fuse coordination due to the high fault current contribution. This paper proposes a separated phase–current control using inverter-based distributed generators (IBDGs) to remove the effects of fault current contributions from SDGs during unsymmetrical faults. The three-phase current [...] Read more.
Synchronous distributed generators (SDGs) significantly affect recloser–fuse coordination due to the high fault current contribution. This paper proposes a separated phase–current control using inverter-based distributed generators (IBDGs) to remove the effects of fault current contributions from SDGs during unsymmetrical faults. The three-phase current produced by IBDGs is independently controlled. While the total fault current is reduced by adjusting the current phase angle in the faulty phase, the energy in the DC-link capacitor (Cdc) is delivered to the grid in order to avoid the rise of DC-link voltage (Vdc) by means of injection of the active current into the nonfaulty phase. To maintain the proper grid voltage, the voltage regulation feature is installed in the IBDGs. Moreover, current estimations programmed within the IBDGs are introduced to avoid the performance degradation of separated phase–current controls caused by phasor measurement units (PMUs). The dynamic performance of the separated phase–current controls using IBDGs was evaluated using an IEEE 34-node radial test feeder. According to the simulation results, the IBDGs could eliminate the effects of fault current contributions from the SDG without interruption since the disconnections caused by excessive Vdc were prevented. They could also regulate the grid voltage in the nonfaulty phase. Full article
(This article belongs to the Section Energy)
Open AccessFeature PaperArticle
Impact of Aeration on the Removal of Organic Matter and Nitrogen Compounds in Constructed Wetlands Treating the Liquid Fraction of Piggery Manure
Appl. Sci. 2019, 9(20), 4310; https://doi.org/10.3390/app9204310 (registering DOI) - 14 Oct 2019
Abstract
The increasing demand for sustainable, robust and cost-efficient wastewater treatment techniques strengthen the implementation of constructed wetlands (CWs) in the agricultural sector. In countries like Belgium (Flanders), the compliance of strict water quality standards and surface area requirements have hindered considerably their application. [...] Read more.
The increasing demand for sustainable, robust and cost-efficient wastewater treatment techniques strengthen the implementation of constructed wetlands (CWs) in the agricultural sector. In countries like Belgium (Flanders), the compliance of strict water quality standards and surface area requirements have hindered considerably their application. New wetland designs such as aerated CWs, could help to overcome these challenges. This study evaluated the capacity of artificially aerated mesocosm systems to decrease chemical oxygen demand (COD) concentrations below the 125 mgO2/L limit imposed on installations treating animal manure. The treatment of this high-strength wastewater has been slightly studied via aerated CWs. A three-stage experiment investigated the effect of constant, intermittent and non-aeration regimes on: ammonium volatilisation, the evolution of organic and nitrogen compounds concentrations, and denitrification. The results were assessed through a mixed modelling procedure using SAS 9.4 software. A COD removal between 65% and 58% in constantly and intermittent aerated systems, versus 27% COD removal in the non-aerated system indicated the effectiveness of aeration. However, a dissimilarity was encountered in the removal of nitrogen compounds, resulting in an 82% decrease of nitrate concentrations in the non-aerated system, versus 0.5% and 11% in the aerated ones. Based on the results, this experimental set-up adjusted to field operational conditions can prove that aerated CWs can treat the liquid fraction of piggery manure. Full article
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Open AccessArticle
Model Updating Using Measurements from Sensors Installed in Arbitrary Positions and Directions
Appl. Sci. 2019, 9(20), 4309; https://doi.org/10.3390/app9204309 (registering DOI) - 14 Oct 2019
Abstract
The present study proposes a method for model updating using measurements from sensors installed in arbitrary positions and directions. Modal identification provides mode shapes for physical quantities (acceleration strain, etc.) measured in specific directions at the location of the sensors. Besides, model updating [...] Read more.
The present study proposes a method for model updating using measurements from sensors installed in arbitrary positions and directions. Modal identification provides mode shapes for physical quantities (acceleration strain, etc.) measured in specific directions at the location of the sensors. Besides, model updating involves the use of the mode shapes related to the nodal degrees-of-freedom of the finite element analytic model. Consequently, the mode shapes obtained by modal identification and the mode shapes of the model updating process do not coincide even for the same mode. Therefore, a method for constructing transform matrices that distinguish the cases where measurement is done by acceleration, velocity, and displacement sensors and the case where measurement is done by strain sensors was proposed to remedy such disagreement among the mode shapes. The so-constructed transform matrices were then applied when the mode shape residual was used as the objective function or for mode pairing in the model updating process. The feasibility of the proposed approach was verified by means of a numerical example in which the strain or acceleration of a simple beam was measured and a numerical example in which the strain of a bridge was measured. Using the proposed approach, it was possible to model the structure regardless of the position of the sensors and to select the location of the sensors independently from the model. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessArticle
Expert System Based on Integrated Fuzzy AHP for Automatic Cutting Tool Selection
Appl. Sci. 2019, 9(20), 4308; https://doi.org/10.3390/app9204308 (registering DOI) - 14 Oct 2019
Abstract
Cutting tool selection plays an important role in achieving reliable quality and high productivity work, and for controlling the total cost of manufacturing. However, it is complicated for process planners to choose the optimal cutting tool when faced with the choice of multiple [...] Read more.
Cutting tool selection plays an important role in achieving reliable quality and high productivity work, and for controlling the total cost of manufacturing. However, it is complicated for process planners to choose the optimal cutting tool when faced with the choice of multiple cutting tools, multiple conflict criteria, and uncertain information. This paper presents an effective method for automatically selecting a cutting tool based on the machining feature characteristics. The optimal cutting tool type is first selected using a proposed multicriteria decision-making method with integrated fuzzy analytical hierarchy process (AHP). The inputs of this process are the feature dimensions, workpiece stability, feature quality, specific machining type, and tool access direction, which determine the cutting tool type priority after evaluating many criteria, such as the material removal capacity, tool cost, power requirement, and flexibility. Expert judgments on the criteria or attributes are collected to determine their weights. The cutting tool types are ranked in ascending order by priority. Then, the rule-based method is applied to determine other specific characteristics of the cutting tool. Cutting tool data are collected from world-leading cutting tool manufacturer, Sandvik, among others. An expert system is established, and an example is given to describe the method and its effectiveness. Full article
(This article belongs to the Section Mechanical Engineering)
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Open AccessArticle
A User-Specific Approach for Comfortable Application of Advanced 3D CAD/CAM Technique in Dental Environments Using the Harmonic Series Noise Model
Appl. Sci. 2019, 9(20), 4307; https://doi.org/10.3390/app9204307 (registering DOI) - 14 Oct 2019
Abstract
Recently, there has been a focus on improving the user’s emotional state by providing high-quality sound beyond noise reduction against industrial product noise. Three-dimensional computer aided design and computer-aided manufacturing (3D CAD/CAM) dental milling machines are a major source of industrial product noise [...] Read more.
Recently, there has been a focus on improving the user’s emotional state by providing high-quality sound beyond noise reduction against industrial product noise. Three-dimensional computer aided design and computer-aided manufacturing (3D CAD/CAM) dental milling machines are a major source of industrial product noise in the dental environment. Here, we propose a noise-control method to improve the sound quality in the dental environment. Our main goals are to analyze the acoustic characteristics of the sounds generated from the dental milling machine, to control the noise by active noise control, and to improve the sound quality of the residual noise by synthesized new sound. In our previous study, we demonstrated noise reduction in dental milling machines through tactile transducers. To improve the sound quality on residual noise, we performed frequency analysis, and synthesized sound similarly as musical instruments, using the harmonic series noise model. Our data suggest that noise improvement through synthesis may prove to be a useful tool in the development of dental devices. Full article
(This article belongs to the Special Issue Sound and Music Computing -- Music and Interaction)
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Open AccessArticle
Cooking/Window Opening and Associated Increases of Indoor PM2.5 and NO2 Concentrations of Children’s Houses in Kaohsiung, Taiwan
Appl. Sci. 2019, 9(20), 4306; https://doi.org/10.3390/app9204306 (registering DOI) - 14 Oct 2019
Abstract
High concentrations of air pollutants and increased morbidity and mortality rates are found in industrial areas, especially for the susceptible group, children; however, most studies use atmospheric dispersion modeling to estimate household air pollutants. Therefore, the aim of this study was to assess [...] Read more.
High concentrations of air pollutants and increased morbidity and mortality rates are found in industrial areas, especially for the susceptible group, children; however, most studies use atmospheric dispersion modeling to estimate household air pollutants. Therefore, the aim of this study was to assess the indoor air quality, e.g., CO, CO2, NO2, SO2, O3, particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5), and their influence factors in children’s homes in an industrial city. Children in the “general school”, “traffic school”, and “industrial school” were randomly and proportionally selected. Air pollutants were sampled for 24 h in the living rooms and on the balcony of their houses and questionnaires of time–microenvironment–activity-diary were recorded. The indoor CO concentration of the traffic area was significantly higher than that of the industrial area and the general area. In regard to the effects of window opening, household NO2 and PM2.5 concentrations during window opening periods were significantly higher than of the reference periods. For the influence of cooking, indoor CO2, NO2, and PM2.5 levels during the cooking periods were significantly higher than that of the reference periods. The indoor air quality of children in industrial cities were affected by residential areas and household activities. Full article
(This article belongs to the Special Issue Indoor Air Quality)
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Open AccessArticle
Advantage of Steerable Catheter and Haptic Feedback for a 5-DOF Vascular Intervention Robot System
Appl. Sci. 2019, 9(20), 4305; https://doi.org/10.3390/app9204305 (registering DOI) - 14 Oct 2019
Abstract
Vascular intervention involves inserting a catheter and guidewire into blood vessels to diagnose and treat a disease in an X-ray environment. In this conventional vascular intervention procedure, the doctor is exposed to considerable radiation. To reduce the exposure, we developed a master–slave robot [...] Read more.
Vascular intervention involves inserting a catheter and guidewire into blood vessels to diagnose and treat a disease in an X-ray environment. In this conventional vascular intervention procedure, the doctor is exposed to considerable radiation. To reduce the exposure, we developed a master–slave robot system. A steerable catheter is employed to shorten the task-time and reduce the contact force applied to the vessel walls during catheter insertion. The steerable catheter helps to select a vascular branch; thus, the radiation exposure time for patients is reduced, and perforation in the patient’s vessel is prevented. Additionally, the robot system employs a haptic function to replicate the physician’s tactile sensing in vascular intervention. In this study, the effectiveness of the steering catheter and haptic function was demonstrated experimentally in comparison with a conventional catheter. Full article
(This article belongs to the Special Issue Next-Generation Surgical Robotics)
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Open AccessArticle
In Vitro Cytotoxicity of Possible Corrosion Products from Mg-Based Biodegradable Metals: Magnesium Oxide and Magnesium Hydroxide Nanoparticles
Appl. Sci. 2019, 9(20), 4304; https://doi.org/10.3390/app9204304 - 14 Oct 2019
Abstract
Biodegradable magnesium (Mg) alloys have potential applications in orthopedic implants due to their mechanical and osseointegration properties. However, the surface characteristics, biocompatibility, and toxicity of the released corrosion products in the form of magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)2) nanoparticles [...] Read more.
Biodegradable magnesium (Mg) alloys have potential applications in orthopedic implants due to their mechanical and osseointegration properties. However, the surface characteristics, biocompatibility, and toxicity of the released corrosion products in the form of magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)2) nanoparticles (NPs) at the junction of implants and in the surrounding tissue are not completely understood. Here, we investigated in vitro cytotoxicity and morphological changes in human fetal osteoblast (hFOB) 1.19 cells in response to various concentrations (1 mM, 5 mM, 10 mM, and 50 mM) of MgO/Mg(OH)2 NPs by live/dead assay and scanning electron microscopy (SEM). In this study, we performed a surface characterization of MgO/Mg(OH)2 NPs to evaluate the size of the NPs. Further, an immersion test was performed in Dulbecco’s Modified Eagle’s Medium (DMEM) with randomly selected various concentrations (1 mM, 5 mM, 10 mM, 50 mM, and 100 mM) of MgO/Mg(OH)2 NPs to understand the degradation behavior of the NPs, and the change in the pH values from days 1 to 7 was measured. After conducting an immersion test for seven days, the highest concentration (100 mM) of MgO/Mg(OH)2 NPs was selected to study the element depositions on nanoparticles through scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDX) mapping. The results from this in vitro cytotoxicity study suggest that less than or equal to 5-mM concentrations of MgO/Mg(OH)2 NPs are tolerable concentrations for hFOB 1.19 cells. This study provides a foundational knowledge of MgO/Mg(OH)2 NP cytotoxicity in hFOB 1.19 cells that can help to develop future sustainable biodegradable magnesium-based alloys for orthopedic applications. Full article
(This article belongs to the Special Issue Degradable/Resorbable Metallic Alloys for Biomedical Applications)
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Open AccessArticle
Computer Adaptive Testing Using Upper-Confidence Bound Algorithm for Formative Assessment
Appl. Sci. 2019, 9(20), 4303; https://doi.org/10.3390/app9204303 - 14 Oct 2019
Abstract
There is strong support for formative assessment inclusion in learning processes, with the main emphasis on corrective feedback for students. However, traditional testing and Computer Adaptive Testing can be problematic to implement in the classroom. Paper based tests are logistically inconvenient and are [...] Read more.
There is strong support for formative assessment inclusion in learning processes, with the main emphasis on corrective feedback for students. However, traditional testing and Computer Adaptive Testing can be problematic to implement in the classroom. Paper based tests are logistically inconvenient and are hard to personalize, and thus must be longer to accurately assess every student in the classroom. Computer Adaptive Testing can mitigate these problems by making use of Multi-Dimensional Item Response Theory at cost of introducing several new problems, most problematic of which are the greater test creation complexity, because of the necessity of question pool calibration, and the debatable premise that different questions measure one common latent trait. In this paper a new approach of modelling formative assessment as a Multi-Armed bandit problem is proposed and solved using Upper-Confidence Bound algorithm. The method in combination with e-learning paradigm has the potential to mitigate such problems as question item calibration and lengthy tests, while providing accurate formative assessment feedback for students. A number of simulation and empirical data experiments (with 104 students) are carried out to explore and measure the potential of this application with positive results. Full article
(This article belongs to the Special Issue Smart Learning)
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Open AccessArticle
Compression of Biomass Substances—A Study on Springback Effects and Color Formation in Pellet Manufacture
Appl. Sci. 2019, 9(20), 4302; https://doi.org/10.3390/app9204302 - 14 Oct 2019
Abstract
In order to increase the use of a variated raw material base for pellet production with a maintained density level, knowledge of the biomaterials’ ability to counteract any springback effects is essential. In this study, the springback effects were investigated for single press [...] Read more.
In order to increase the use of a variated raw material base for pellet production with a maintained density level, knowledge of the biomaterials’ ability to counteract any springback effects is essential. In this study, the springback effects were investigated for single press produced pellets from cellulose, hemicelluloses, pectin, and two woods at different moisture contents. The change in pellet coloring was also tested through a spectrophotometer for both xylan and carboxymethyl cellulose (CMC) pellets. The results show that the density of xylan pellets is much higher than glucomannan, for both green and cured pellets, and that the length of the pellets, as well as springback contribution, differ between the hemicelluloses. The study also presents results showing that both xylan and CMC pellets have a mutually identical spectrum and that the changes in the structure of xylan are not only related to moisture content, but are also pressure-related. The study also postulates that the color difference of the xylan pellets is a result of physical changes in the structure, as opposed to being of a chemical nature. Full article
(This article belongs to the Special Issue Biomass Research and Applications)
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Open AccessArticle
The Effect of Patellar Tendon Release on the Characteristics of Patellofemoral Joint Squat Movement: A Simulation Analysis
Appl. Sci. 2019, 9(20), 4301; https://doi.org/10.3390/app9204301 - 14 Oct 2019
Viewed by 35
Abstract
Objectives: This paper studies the patellar tendon release’s effect on the movement characteristics of the artificial patellofemoral joint squat to provide reference data for knee joint surgery. Methods: Firstly, the dynamic finite element model of the human knee joint under squatting was established. [...] Read more.
Objectives: This paper studies the patellar tendon release’s effect on the movement characteristics of the artificial patellofemoral joint squat to provide reference data for knee joint surgery. Methods: Firstly, the dynamic finite element model of the human knee joint under squatting was established. Secondly, in the above no-release models, the release of 30% of the attachment area at the upper end, the lower end, or both ends of the patellar tendon were conducted, respectively. Then the simulations of all above four models were conducted. Finally, the results of the simulation were compared and analyzed. Results: The simulation results show that, after releasing the patellar tendon (compared with the no-release simulation’s results), the relative flexion, medial-lateral rotation, medial-lateral tilt, and superior-inferior shift of the patella relative to the femur increased; the medial-lateral shift and anterior-posterior shift of the patella relative to the femur decreased. Conclusion: In this paper, the maximum flexion angle of the patella increased after the patellar tendon being released (compared with the no-release model), which indicated that the mobility of knee joint was improved after the patellar tendon release. The simulation data in this paper can provide technical reference for total knee arthroplasty. Full article
(This article belongs to the Special Issue Engineering for Surgery)
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Open AccessArticle
Optimization of Nonspherical Gold Nanoparticles for Photothermal Therapy
Appl. Sci. 2019, 9(20), 4300; https://doi.org/10.3390/app9204300 - 13 Oct 2019
Viewed by 163
Abstract
Previous investigations devoted to the optimization of nonspherical gold nanoparticles for photothermal therapy (PTT) encountered two issues, namely, the appropriate selection of objective functions and the processing of particle random orientations. In this study, these issues were resolved, and accurate optimization results were [...] Read more.
Previous investigations devoted to the optimization of nonspherical gold nanoparticles for photothermal therapy (PTT) encountered two issues, namely, the appropriate selection of objective functions and the processing of particle random orientations. In this study, these issues were resolved, and accurate optimization results were obtained for the three typical nonspherical gold nanoparticles (nanospheroid, nanocylinder, and nanorod) by using the T-matrix method. The dependence of the optimization results on the excitation wavelength and the refractive index of tissue was investigated. Regardless of the excitation wavelength and tissue type, gold nanospheroids were found to be the most effective therapeutic agents for PTT. The light absorption ability of optimized nanoparticles could be enhanced by using a laser with a longer wavelength. Finally, the design tolerance for the different sizes of nanoparticles was provided. Full article
(This article belongs to the Special Issue Nanoparticles for Diagnosis and Therapies)
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Open AccessFeature PaperArticle
Characterization of Four Liver-Expressed Antimicrobial Peptides from Antarctic Fish and Their Antibacterial Activity
Appl. Sci. 2019, 9(20), 4299; https://doi.org/10.3390/app9204299 - 13 Oct 2019
Viewed by 179
Abstract
Liver-expressed antimicrobial peptides (LEAPs) are cysteine-containing cationic peptides. LEAP-1 and LEAP-2 are eight- and four-cysteine containing antimicrobial peptides found in humans, respectively. LEAP-1 is a widely known antibacterial peptide involved in the innate immunity of fish, but the roles of LEAP-1 and LEAP-2 [...] Read more.
Liver-expressed antimicrobial peptides (LEAPs) are cysteine-containing cationic peptides. LEAP-1 and LEAP-2 are eight- and four-cysteine containing antimicrobial peptides found in humans, respectively. LEAP-1 is a widely known antibacterial peptide involved in the innate immunity of fish, but the roles of LEAP-1 and LEAP-2 in Antarctic fish species such as notothenioid and eelpout are still unknown. In the present study, we synthesized and characterized novel LEAPs with four and eight cysteine residues, derived from Antarctic notothenioid (Dissostichus mawsoni) and Antarctic eelpout (Lycodichthys dearborni). Circular dichroism spectroscopy of these peptides showed a typical β-sheet confirmation. The LEAPs were found to be bactericidal against gram-positive as well as gram-negative bacteria. In the SYTOX green uptake assay, LEAPs did not trigger any significant increase in fluorescence. LEAPs competitively bind to DNA and replace the ethidium bromide (EB) dye. To determine the effect of temperature on LEAPs, we evaluated the antibacterial activity against Listeria monocytogenes at 5, 15, 25, and 35 °C. The results showed that the antibacterial activity of LEAPs decreases with an increase in temperature. Taken together, our results suggest that novel LEAPs with four and eight cysteine residues are bactericidal, with the likely mode of action being DNA binding. Full article
(This article belongs to the Special Issue Cold-Active Proteins: Proteinase and Lipase)
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Open AccessArticle
Two-Step Feature Selection for Identifying Developmental Differences in Resting fMRI Intrinsic Connectivity Networks
Appl. Sci. 2019, 9(20), 4298; https://doi.org/10.3390/app9204298 - 12 Oct 2019
Viewed by 159
Abstract
Functional connectivity derived from functional magnetic resonance imaging (fMRI) is used as an effective way to assess brain architecture. There has been a growing interest in its application to the study of intrinsic connectivity networks (ICNs) during different brain development stages. fMRI data [...] Read more.
Functional connectivity derived from functional magnetic resonance imaging (fMRI) is used as an effective way to assess brain architecture. There has been a growing interest in its application to the study of intrinsic connectivity networks (ICNs) during different brain development stages. fMRI data are of high dimension but small sample size, and it is crucial to perform dimension reduction before pattern analysis of ICNs. Feature selection is thus used to reduce redundancy, lower the complexity of learning, and enhance the interpretability. To study the varying patterns of ICNs in different brain development stages, we propose a two-step feature selection method. First, an improved support vector machine based recursive feature elimination method is utilized to study the differences of connectivity during development. To further reduce the highly correlated features, a combination of F-score and correlation score is applied. This method was then applied to analysis of the Philadelphia Neurodevelopmental Cohort (PNC) data. The two-step feature selection was randomly performed 20 times, and those features that showed up consistently in the experiments were chosen as the essential ICN differences between different brain ages. Our results indicate that ICN differences exist in brain development, and they are related to task control, cognition, information processing, attention, and other brain functions. In particular, compared with children, young adults exhibit increasing functional connectivity in the sensory/somatomotor network, cingulo-opercular task control network, visual network, and some other subnetworks. In addition, the connectivity in young adults decreases between the default mode network and other subnetworks such as the fronto-parietal task control network. The results are coincident with the fact that the connectivity within the brain alters from segregation to integration as an individual grows. Full article
Open AccessArticle
Magnetic Properties of NiZn Ferrite Nanofibers Prepared by Electrospinning
Appl. Sci. 2019, 9(20), 4297; https://doi.org/10.3390/app9204297 - 12 Oct 2019
Viewed by 138
Abstract
When the size of a material is decreased to the nanoscale, the effects of forces that are not influential on a macroscopic scale become increasingly important and the electronic structure is improved. The material then exhibits significantly different physical and chemical properties than [...] Read more.
When the size of a material is decreased to the nanoscale, the effects of forces that are not influential on a macroscopic scale become increasingly important and the electronic structure is improved. The material then exhibits significantly different physical and chemical properties than in the bulk state. The smaller the size of the material, the more exposure it receives to the nano effects, and the physical properties can be changed via size control. In this study, Ni0.5Zn0.5Fe2O4 ferrite nanofibers were prepared by electrospinning, and the sizes of the prepared samples were controlled to ensure different average diameters by controlling the polymer concentration of the precursor solution. Field emission scanning electron microscope images showed that the samples had average diameters of 224 to 265 nm. The single crystal phase of Ni0.5Zn0.5Fe2O4 and the different crystallite sizes of 13 to 20 nm were confirmed by X-ray diffraction analysis. The magnetization behavior of the samples was measured using a vibrating sample magnetometer and the result confirmed that the samples had different magnetic properties, according to the diameter and crystallite size of the nanofibers. This study suggests that control of magnetic properties and excellent electrical conductivity in a one-dimensional nanostructure can be positively applied to improve the performance of a filler for the electromagnetic-interference shielding film. Full article
(This article belongs to the Section Materials)
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Open AccessArticle
Physical and Mechanical Properties of Composite Scaffolds with or without Collagen Impregnation
Appl. Sci. 2019, 9(20), 4296; https://doi.org/10.3390/app9204296 - 12 Oct 2019
Viewed by 158
Abstract
This in vitro study aimed at evaluating the physical and mechanical properties of newly developed scaffolds of poly (lactic-co-glycolic acid) (PLGA) and biphasic ceramic (Hydroxyapatite HA + beta-tricalciumphosphate β-TCP) with or without collagen impregnation to be used for bone regeneration in the oral [...] Read more.
This in vitro study aimed at evaluating the physical and mechanical properties of newly developed scaffolds of poly (lactic-co-glycolic acid) (PLGA) and biphasic ceramic (Hydroxyapatite HA + beta-tricalciumphosphate β-TCP) with or without collagen impregnation to be used for bone regeneration in the oral and maxillofacial district. Solvent casting and particle leaching techniques were used to produce the scaffolds, which were then divided into six groups according to PLGA/HA + β-TCP ratio and impregnation with collagen: G1 (50/50) + collagen; G2 (60/40) + collagen; G3 (40/60) + collagen; G4 (50/50); G5 (60/40); G6 (40/60). As control group, inorganic xenogenous bone was used. Structure and porosity were evaluated by scanning electron microscopy, and a chemical analysis was performed through an energy-dispersive spectrometer. Moreover, to evaluate the hydrophilicity of the samples, a wettability test was conceived, and finally, mechanical properties were examined by a compression test. High porosity and interconnectivity, resulting in a large surface area and great fluid retention capacity, were presented by the PLGA/HA + β-TCP scaffolds. In the composite groups, collagen increased the wettability and the mechanical resistance, although the latter was not statistically affected by the percentage of HA + β-TCP added. Further in vitro and in vivo studies are needed for a deeper understanding of the influence of collagen on the biological behavior of the developed composite materials and their potential, namely biocompatibility and bioactivity, for bone tissue regeneration. Full article
(This article belongs to the Special Issue Bio-Inspired Biodegradable Scaffold Constructs for Bone Tissue Repair)
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Open AccessArticle
Development and Control of an Electro-Hydraulic Actuator System for an Exoskeleton Robot
Appl. Sci. 2019, 9(20), 4295; https://doi.org/10.3390/app9204295 - 12 Oct 2019
Viewed by 144
Abstract
Exoskeleton robots have been developed in various fields and are divided into electric and hydraulic exoskeletons according to the actuator type. In the case of hydraulic robots, because a unidirectional pump is applied, there are limitations to the wearer’s walking. In addition, robot [...] Read more.
Exoskeleton robots have been developed in various fields and are divided into electric and hydraulic exoskeletons according to the actuator type. In the case of hydraulic robots, because a unidirectional pump is applied, there are limitations to the wearer’s walking. In addition, robot systems are complicated, because a directional control valve is required to change the direction of the actuator. To solve these problems, we designed the electro-hydraulic actuator (EHA) system which has both the hydraulic and electric advantages. The EHA system consists of a hydraulic bidirectional pump, a motor, a hydraulic cylinder, and various valves. For the development of the piston pump, we analyzed the gait cycle and considered the flow rate and pulsation rate. In order to reduce the size and weight of the EHA system, the valves were made from one manifold, and the hydraulic circuit was simplified. We verified that the developed EHA system is applicable to robots through position and force control experiments. Because the hydraulic system is nonlinear, we designed a sliding mode control (SMC) and compared it with the proportional integral derivative (PID) controller. Full article
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Open AccessArticle
Design and Analysis of a Chinese Medicine Based Humanoid Robotic Arm Massage System
Appl. Sci. 2019, 9(20), 4294; https://doi.org/10.3390/app9204294 - 12 Oct 2019
Viewed by 139
Abstract
This paper presents a humanoid robotic arm massage system with an aim toward satisfying the clinical requirements of pain relief on the waist and legs of older patients during Chinese medicinal massage. On the basis of an in-depth analysis regarding the characteristics of [...] Read more.
This paper presents a humanoid robotic arm massage system with an aim toward satisfying the clinical requirements of pain relief on the waist and legs of older patients during Chinese medicinal massage. On the basis of an in-depth analysis regarding the characteristics of arm joints of the human body and Chinese medicinal massage theory, a humanoid robotic arm massage system was designed by adapting a bottom to top modular method. The combined finite element and kinematic analysis led to an improved performance according to repeated positioning accuracy, massage strength accuracy, and massage effect. The developed humanoid robotic arm was characterized by a compact structure, high precision, light quality, and good stiffness, achieving a good bearing capacity. Due to the PID controller, the numerical simulations and experimental results provided valuable insight into the development of Chinese medicinal massage robots and massage treatments for patients who suffer from lumbar muscle strain. Full article
(This article belongs to the Section Applied Biosciences and Bioengineering)
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