Applied Sciences

9 pages, 1332 KiB

Open AccessArticle

Measurement of the Absolute Value of Cerebral Blood Volume and Optical Properties in Term Neonates Immediately after Birth Using Near-Infrared Time-Resolved Spectroscopy: A Preliminary Observation Study

by Aya Morimoto, Shinji Nakamura, Masashiro Sugino, Kosuke Koyano, Yinmon Htun, Makoto Arioka, Noriko Fuke, Ami Mizuo, Takayuki Yokota, Ikuko Kato, Yukihiko Konishi, Sonoko Kondo, Takashi Iwase, Saneyuki Yasuda and Takashi Kusaka

Appl. Sci. 2019, 9(10), 2172; https://doi.org/10.3390/app9102172 - 27 May 2019

Cited by 7 | Viewed by 3275

Abstract

The aim of this study was to use near-infrared time-resolved spectroscopy (TRS) to determine the absolute values of cerebral blood volume (CBV) and cerebral hemoglobin oxygen saturation (ScO₂) during the immediate transition period in term neonates and the changes in optical [...] Read more.

The aim of this study was to use near-infrared time-resolved spectroscopy (TRS) to determine the absolute values of cerebral blood volume (CBV) and cerebral hemoglobin oxygen saturation (ScO₂) during the immediate transition period in term neonates and the changes in optical properties such as the differential pathlength factor (DPF) and reduced scattering coefficient (μ_s’). CBV and ScO₂ were measured using TRS during the first 15 min after birth by vaginal delivery in term neonates who did not need resuscitation. Within 2–3 min after birth, CBV showed various changes such as increases or decreases, followed by a gradual decrease until 15 min and then stability (mean (SD) mL/100 g brain: 2 min, 3.09 (0.74); 3 min, 3.01 (0.77); 5 min, 2.69 (0.77); 10 min, 2.40 (0.61), 15 min, 2.08 (0.47)). ScO₂ showed a gradual increase, then kept increasing or became a stable reading. The DPF and μ_s’ values (mean (SD) at 762, 800, and 836 nm) were stable during the first 15 min after birth (DPF: 4.47 (0.38), 4.41 (0.32), and 4.06 (0.28)/cm; μ_s’: 6.54 (0.67), 5.82 (0.84), and 5.43 (0.95)/cm). Accordingly, we proved that TRS can stably measure cerebral hemodynamics, despite the dramatic physiological changes occurring at this time in the labor room. Full article

(This article belongs to the Special Issue New Horizons in Time-Domain Diffuse Optical Spectroscopy and Imaging)

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14 pages, 5054 KiB

Open AccessArticle

Automatic Digital Modulation Classification Based on Curriculum Learning

by Min Zhang, Zhongwei Yu, Hai Wang, Hongbo Qin, Wei Zhao and Yan Liu

Appl. Sci. 2019, 9(10), 2171; https://doi.org/10.3390/app9102171 - 27 May 2019

Cited by 17 | Viewed by 4061

Abstract

Neural network shows great potential in modulation classification because of its excellent accuracy and achievability but overfitting and memorizing data noise often happen in previous researches on automatic digital modulation classifier. To solve this problem, we utilize two neural networks, namely MentorNet and [...] Read more.

Neural network shows great potential in modulation classification because of its excellent accuracy and achievability but overfitting and memorizing data noise often happen in previous researches on automatic digital modulation classifier. To solve this problem, we utilize two neural networks, namely MentorNet and StudentNet, to construct an automatic modulation classifier, which possesses great performance on the test set with −18–20 dB signal-to-noise ratio (SNR). The MentorNet supervises the training of StudentNet according to curriculum learning, and deals with the overfitting problem in StudentNet. The proposed classifier is verified in several test sets containing additive white Gaussian noise (AWGN), Rayleigh fading, carrier frequency offset and phase offset. Experimental results reveal that the overall accuracy of this classifier for common eleven modulation types was up to 99.3% while the inter-class accuracy could be up to 100%, which was much higher than many other classifiers. Besides, in the presence of interferences, the overall accuracy of this novel classifier still could reach 90% at 10 dB SNR indicting its excellent robustness, which makes it suitable for applications like military electronic warfare. Full article

(This article belongs to the Section Electrical, Electronics and Communications Engineering)

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17 pages, 936 KiB

Open AccessArticle

Chronic Disease Prediction Using Character-Recurrent Neural Network in The Presence of Missing Information

by Changgyun Kim, Youngdoo Son and Sekyoung Youm

Appl. Sci. 2019, 9(10), 2170; https://doi.org/10.3390/app9102170 - 27 May 2019

Cited by 16 | Viewed by 4712

Abstract

The aim of this study was to predict chronic diseases in individual patients using a character-recurrent neural network (Char-RNN), which is a deep learning model that treats data in each class as a word when a large portion of its input values is [...] Read more.

The aim of this study was to predict chronic diseases in individual patients using a character-recurrent neural network (Char-RNN), which is a deep learning model that treats data in each class as a word when a large portion of its input values is missing. An advantage of Char-RNN is that it does not require any additional imputation method because it implicitly infers missing values considering the relationship with nearby data points. We applied Char-RNN to classify cases in the Korea National Health and Nutrition Examination Survey (KNHANES) VI as normal status and five chronic diseases: hypertension, stroke, angina pectoris, myocardial infarction, and diabetes mellitus. We also employed a multilayer perceptron network for the same task for comparison. The results show higher accuracy for Char-RNN than for the conventional multilayer perceptron model. Char-RNN showed remarkable performance in finding patients with hypertension and stroke. The present study utilized the KNHANES VI data to demonstrate a practical approach to predicting and managing chronic diseases with partially observed information. Full article

(This article belongs to the Special Issue Advances in Deep Learning)

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10 pages, 1192 KiB

Open AccessArticle

Solids Content of Black Liquor Measured by Online Time-Domain NMR

by Ekaterina Nikolskaya, Petri Janhunen, Mikko Haapalainen and Yrjö Hiltunen

Appl. Sci. 2019, 9(10), 2169; https://doi.org/10.3390/app9102169 - 27 May 2019

Cited by 16 | Viewed by 4503

Abstract

Black liquor, a valuable by-product of the pulp production process, is used for the recovery of chemicals and serves as an energy source for the pulp mill. Before entering the recovery unit, black liquor runs through several stages of evaporation, wherein the solids [...] Read more.

Black liquor, a valuable by-product of the pulp production process, is used for the recovery of chemicals and serves as an energy source for the pulp mill. Before entering the recovery unit, black liquor runs through several stages of evaporation, wherein the solids content (SC) can be used to control the evaporation effectiveness. In the current study, the time-domain nuclear magnetic resonance (TD-NMR) technique was applied to determine the SC of black liquor. The TD-NMR system was modified for flowing samples, so that the black liquor could be pumped through the system, followed by the measurement of the spin-spin relaxation rate, R₂. A temperature correction was also applied to reduce deviations in the R₂ caused by the sample temperature. The SC was calculated based on a linear model between the R₂ and the SC values determined gravimetrically, where good agreement was shown. The online TD-NMR system was tested at a pulp mill for the SC estimation of weak black liquor over seven days without any fouling, which demonstrated the feasibility of the method in a harsh industrial environment. Therefore, the potential of the TD-NMR technology as a technique for controlling the black liquor evaporation process was demonstrated. Full article

(This article belongs to the Special Issue Applications of Low Field Magnetic Resonance)

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Schematic overview of the online time-domain nuclear magnetic resonance (TD-NMR) measuring system. Full article ">Figure 2
R2 measured for the weak (triangles), intermediate (squares), and half-strong (circles) black liquor samples at different temperatures. Full article ">Figure 3
Solids content (SCs) as a function of the spin-spin relaxation rates ln(R2TC) corrected to Tref = 60 °C for the black liquor samples. Full article ">Figure 4
Data measured for the weak black liquor in the online test: (a) Sample temperature; (b) Measured R2 values and values of the R2TC corrected to Tref = 60 °C, after applying a one-hour moving average; (c) Temperature correction at the beginning of the test (dotted rectangle in <a href="#applsci-09-02169-f004" class="html-fig">Figure 4</a>b): measured R2 (squares), values of the R2TC corrected to Tref = 60 °C (circles), and the sample temperature T (triangles). Full article ">Figure 5
Estimated solids content (SC) shown by a black line, and standard deviations (SD) shown by the grey lines. Average SCs and SDs were estimated within one hour, using moving data. Full article ">

20 pages, 7400 KiB

Open AccessArticle

A Worm-Inspired Robot Flexibly Steering on Horizontal and Vertical Surfaces

by Wenhao Yang and Wenzeng Zhang

Appl. Sci. 2019, 9(10), 2168; https://doi.org/10.3390/app9102168 - 27 May 2019

Cited by 11 | Viewed by 4484

Abstract

Based on the motion principle of bionic earthworms, we designed and fabricated a novel crawling robot driven by pneumatic power. Its structure is divided into four segments, and its motion process is periodic with high stability. Due to the pneumatic suction cups mounted [...] Read more.

Based on the motion principle of bionic earthworms, we designed and fabricated a novel crawling robot driven by pneumatic power. Its structure is divided into four segments, and its motion process is periodic with high stability. Due to the pneumatic suction cups mounted on its feet, it is able to crawl on smooth horizontal, inclined, or vertical walls. On this basis, we designed a novel underactuated steering mechanism. Through the tendons on both sides and the springs installed on the side of the robot, we accurately controlled the steering motion of the robot. We analyzed the steering process in detail, calculated the influence of external parameters on the steering process of the robot, and simulated the trajectory of the robot in the steering process. The experimental results validated our analysis. In addition, we calculate the maximum thrust that each segment of the robot can provide, and determine the maximum load that the robot can bear during climbing motions. Full article

(This article belongs to the Section Mechanical Engineering)

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18 pages, 6098 KiB

Open AccessFeature PaperArticle

Reactive Black 5 Degradation on Manganese Oxides Supported on Sodium Hydroxide Modified Graphene Oxide

by Hayarpi Saroyan, Dimitra Ntagiou, Kyriazis Rekos and Eleni Deliyanni

Appl. Sci. 2019, 9(10), 2167; https://doi.org/10.3390/app9102167 - 27 May 2019

Cited by 22 | Viewed by 4349

Abstract

Sodium hydroxide-modified graphene oxide was used as manganese oxides support for the preparation of nanocomposites via a one-pot preparation route for the degradation of Reactive Black 5. The nanocomposites were characterized for their structure by X-ray diffraction, for their textural properties by Nitrogen [...] Read more.

Sodium hydroxide-modified graphene oxide was used as manganese oxides support for the preparation of nanocomposites via a one-pot preparation route for the degradation of Reactive Black 5. The nanocomposites were characterized for their structure by X-ray diffraction, for their textural properties by Nitrogen adsorption, and for their surface chemistry by Fourier transform infrared spectroscopy, potentiometric titration, and thermal analysis measurements. The nanocomposites prepared showed to possess high activity for the degradation/oxidation of Reactive Black 5 at ambient conditions, without light irradiation, which was higher than that of the precursors manganese oxides and can be attributed to the synergistic effect of the manganese oxides and the modified graphene oxide. Full article

(This article belongs to the Special Issue Innovative Approaches for Drinking- and Waste-Water Treatment)

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13 pages, 2650 KiB

Open AccessArticle

Enhanced Automatic Speech Recognition System Based on Enhancing Power-Normalized Cepstral Coefficients

by Mohamed Tamazin, Ahmed Gouda and Mohamed Khedr

Appl. Sci. 2019, 9(10), 2166; https://doi.org/10.3390/app9102166 - 27 May 2019

Cited by 22 | Viewed by 4234

Abstract

Many new consumer applications are based on the use of automatic speech recognition (ASR) systems, such as voice command interfaces, speech-to-text applications, and data entry processes. Although ASR systems have remarkably improved in recent decades, the speech recognition system performance still significantly degrades [...] Read more.

Many new consumer applications are based on the use of automatic speech recognition (ASR) systems, such as voice command interfaces, speech-to-text applications, and data entry processes. Although ASR systems have remarkably improved in recent decades, the speech recognition system performance still significantly degrades in the presence of noisy environments. Developing a robust ASR system that can work in real-world noise and other acoustic distorting conditions is an attractive research topic. Many advanced algorithms have been developed in the literature to deal with this problem; most of these algorithms are based on modeling the behavior of the human auditory system with perceived noisy speech. In this research, the power-normalized cepstral coefficient (PNCC) system is modified to increase robustness against the different types of environmental noises, where a new technique based on gammatone channel filtering combined with channel bias minimization is used to suppress the noise effects. The TIDIGITS database is utilized to evaluate the performance of the proposed system in comparison to the state-of-the-art techniques in the presence of additive white Gaussian noise (AWGN) and seven different types of environmental noises. In this research, one word is recognized from a set containing 11 possibilities only. The experimental results showed that the proposed method provides significant improvements in the recognition accuracy at low signal to noise ratios (SNR). In the case of subway noise at SNR = 5 dB, the proposed method outperforms the mel-frequency cepstral coefficient (MFCC) and relative spectral (RASTA)–perceptual linear predictive (PLP) methods by 55% and 47%, respectively. Moreover, the recognition rate of the proposed method is higher than the gammatone frequency cepstral coefficient (GFCC) and PNCC methods in the case of car noise. It is enhanced by 40% in comparison to the GFCC method at SNR 0dB, while it is improved by 20% in comparison to the PNCC method at SNR −5dB. Full article

(This article belongs to the Section Electrical, Electronics and Communications Engineering)

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17 pages, 1308 KiB

Open AccessArticle

Impact of Copper Oxide Nanoparticles on Enhancement of Bioactive Compounds Using Cell Suspension Cultures of Gymnema sylvestre (Retz.) R. Br

by Ill-Min Chung, Govindasamy Rajakumar, Umadevi Subramanian, Baskar Venkidasamy and Muthu Thiruvengadam

Appl. Sci. 2019, 9(10), 2165; https://doi.org/10.3390/app9102165 - 27 May 2019

Cited by 50 | Viewed by 5027

Abstract

Gymnema sylvestre is a plant that is enriched in bioactive compounds. In particular, gymnemic acids (GA) and phenolic compounds (PC) are pharmaceutically important. There is a commercial demand for naturally occurring bioactive compounds, but their availability is limited due to geographical and seasonal [...] Read more.

Gymnema sylvestre is a plant that is enriched in bioactive compounds. In particular, gymnemic acids (GA) and phenolic compounds (PC) are pharmaceutically important. There is a commercial demand for naturally occurring bioactive compounds, but their availability is limited due to geographical and seasonal variations. The elicitation approach can enhance the biosynthesis of phytochemicals during in vitro culture of G. sylvestre. Here, to further improve gymnemic acid II (GA II) and phenolic compounds (PC) production by G. sylvestre, cell suspension cultures (CSC), which has attracted attention for the production of essential phytochemicals, was explored using copper oxide nanoparticles (CuO NPs). Callus was obtained on MS medium containing 2,4-dichlorophenoxyacetic acid, kinetin, phytoagar, and sucrose. Agar-free MS medium was used to initiate CSC, which was treated with three concentrations of CuO NPs (1, 3 or 5 mg/L). Treatment for 48 h with 3 mg/L CuO NPs resulted in the greatest yields of GA II, total phenolics, and flavonoids. The cultures also displayed pronounced antioxidant, antidiabetic, anti-inflammatory, antibacterial, antifungal, and anticancer activities. The use of CuO NPs (3 mg/L) significantly increased the production of GA II (nine-fold) and PC compared to unamended CSC. We propose that CSC and use of nanoparticles (NPs) as a new generation of elicitors, offer a suitable prospect for the production of bioactive compounds. Full article

(This article belongs to the Special Issue Bioactive Substances: Properties, Applications and or Toxicities)

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Callus induction and biomass accumulation in Gymnema sylvestre. (a) Effect of different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) in combination with 0.1 mg/L kinetin (KIN) for callus induction in G. sylvestre. (b) Biomass accumulation. (c) Gymnemic Acid II (GA II) production on MS liquid medium with 2,4-D (2 mg/L), KIN (0.1 mg/L), and sucrose (30 g/L) with time. Different letters indicate a significant difference at p ≤ 0.05. Full article ">Figure 2
Effect of copper oxide nanoparticles (CuO NPs) on copper content and biomass accumulation in cell suspension cultures (CSC) of G. sylvestre. (a) Copper content, (b) biomass accumulation. Different letters indicate a significant difference at p ≤ 0.05. Full article ">Figure 3
Effect of CuO NPs on bioactive compounds in CSC of G. sylvestre. (a) Gymnemic acid II (GA II), (b) Total phenolic content (TPC), (c) Total flavonoid content (TFC). Different letters indicate a significant difference at p ≤ 0.05. Full article ">Figure 4
Effect of CuO NPs on antioxidant activities in CSC of G. sylvestre. (a) Free radical-scavenging activity by the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay, (b) total Fe3+– Fe2+ reductive potential reference antioxidants (butylated hydroxytoluene), (c) total antioxidant capacity (TAC) by the phosphomolybdenum method. TAC is expressed as equivalents of α-tocopherol (μg/g of extract). Different letters indicate a significant difference at p ≤ 0.05. Full article ">Figure 5
Effect of CuO NPs on antidiabetic and anti-inflammatory activities in CSC of G. sylvestre. (a) In vitro α-amylase activity, (b) non-enzymatic glycosylation of hemoglobin activity, (c) lipoxygenase inhibition activity, (d) albumin denaturation inhibition assay. Different letters indicate a significant difference at p ≤ 0.05. Full article ">Figure 6
Effect of CuO NPs on antimicrobial activity in CSC of G. sylvestre using the disc diffusion method. Different letters indicate a significant difference at p ≤ 0.05. Full article ">Figure 7
Effect of CuO NPs on cell viability of MCF-7 cells (a) and HT-29 cells (b) in CSC of G. sylvestre. Different letters indicate a significant difference at p ≤ 0.05. Full article ">

20 pages, 3807 KiB

Open AccessArticle

Study of Heat and Mass Transfer in Electroosmotic Flow of Third Order Fluid through Peristaltic Microchannels

by Sadia Waheed, Saima Noreen and Abid Hussanan

Appl. Sci. 2019, 9(10), 2164; https://doi.org/10.3390/app9102164 - 27 May 2019

Cited by 45 | Viewed by 3948

Abstract

An analysis is carried out to evaluate the effects of heat and mass transfer in an electro-osmotic flow of third order fluid via peristaltic pumping. Solutions are derived for small wave number and Peclet number. The emerging non-linear mathematical model is solved analytically [...] Read more.

An analysis is carried out to evaluate the effects of heat and mass transfer in an electro-osmotic flow of third order fluid via peristaltic pumping. Solutions are derived for small wave number and Peclet number. The emerging non-linear mathematical model is solved analytically and compared numerically by the built-in scheme of working software. The table is inserted for shear stress distribution and a graph for comparison of solution techniques and accuracy of obtained results. The effects of various parameters of interest on pumping, trapping, temperature, heat transfer coefficient, and concentration distribution have been studied graphically. Electro-osmotic exchange of energy and mass has a role in reservoir engineering, chemical industry, and in micro-fabrication technologies. Full article

(This article belongs to the Special Issue Heat and Mass Transfer: Fundamentals and Applications in Thermal Energy)

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10 pages, 1910 KiB

Open AccessArticle

Energy Concepts and Critical Plane for Fatigue Assessment of Ti-6Al-4V Notched Specimens

by Camilla Ronchei, Andrea Carpinteri and Sabrina Vantadori

Appl. Sci. 2019, 9(10), 2163; https://doi.org/10.3390/app9102163 - 27 May 2019

Cited by 5 | Viewed by 2460

Abstract

In the present paper, the fatigue life assessment of notched structural components is performed by applying a critical plane-based multiaxial fatigue criterion. Such a criterion is formulated by using the control volume concept related to the strain energy density criterion. The verification point [...] Read more.

In the present paper, the fatigue life assessment of notched structural components is performed by applying a critical plane-based multiaxial fatigue criterion. Such a criterion is formulated by using the control volume concept related to the strain energy density criterion. The verification point is assumed to be at a given distance from the notch tip. Such a distance is taken as a function of the control volume radii around the notch tip under both Mode I and Mode III loading. The accuracy of the present criterion is evaluated through experimental data available in the literature, concerning titanium alloy notched specimens under uniaxial and multiaxial fatigue loading. Full article

(This article belongs to the Special Issue Fracture and Fatigue Assessments of Structural Components)

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Verification point position according to the control volume concept for V-notch. Full article ">Figure 2
Discretization adopted for the finite element model. Full article ">Figure 3
Geometrical sizes of the titanium alloy V-notched specimens subjected to tension and/or torsion fatigue loading. Full article ">Figure 4
Accuracy of the present criterion in estimating the fatigue lifetime of Ti-6Al-4V notched specimens: (a) Uniaxial loading, (b) multiaxial proportional loading, (c) multiaxial non-proportional loading. Full article ">Figure 5
Experimental fatigue life <math display="inline"><semantics> <mrow> <msub> <mi>N</mi> <mrow> <mi>f</mi> <mo>,</mo> <mi mathvariant="italic">exp</mi> </mrow> </msub> </mrow> </semantics></math> against equivalent strain amplitude <math display="inline"><semantics> <mrow> <msub> <mi>ε</mi> <mrow> <mi>e</mi> <mi>q</mi> <mo>,</mo> <mi>a</mi> </mrow> </msub> </mrow> </semantics></math>. Full article ">Figure 6
Absolute value of the error index <math display="inline"><semantics> <mi>I</mi> </semantics></math> according to the present criterion. Full article ">

14 pages, 2343 KiB

Open AccessArticle

Dynamic Response Analysis of a Simply Supported Double-Beam System under Successive Moving Loads

by Lizhong Jiang, Yuntai Zhang, Yulin Feng, Wangbao Zhou and Zhihua Tan

Appl. Sci. 2019, 9(10), 2162; https://doi.org/10.3390/app9102162 - 27 May 2019

Cited by 28 | Viewed by 3804

Abstract

The dynamic response of a simply supported double-beam system under moving loads was studied. First, in order to reduce the difficulty of solving the equation, a finite sin-Fourier transform was used to transform the infinite-degree-of-freedom double-beam system into a superimposed two-degrees-of-freedom system. Second, [...] Read more.

The dynamic response of a simply supported double-beam system under moving loads was studied. First, in order to reduce the difficulty of solving the equation, a finite sin-Fourier transform was used to transform the infinite-degree-of-freedom double-beam system into a superimposed two-degrees-of-freedom system. Second, Duhamel’s integral was used to obtain the analytical expression of Fourier amplitude spectrum function considering the initial conditions. Finally, based on finite sin-Fourier inverse transform, the analytical expression of dynamic response of a simply supported double-beam system under moving loads was deduced. The dynamic response under successive moving loads was calculated by the analytical method and the general FEM software ANSYS. The analysis results show that the analytical method calculation results are consistent with ANSYS’ calculation, thus validating the analytical calculation method. The simply supported double-beam system had multiple critical speeds, and the flexural rigidity significantly affected both peak vertical displacement and critical speed. Full article

(This article belongs to the Special Issue Bridge Dynamics)

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12 pages, 2908 KiB

Open AccessArticle

Multiscale Superpixelwise Locality Preserving Projection for Hyperspectral Image Classification

by Lin He, Xianjun Chen, Jun Li and Xiaofeng Xie

Appl. Sci. 2019, 9(10), 2161; https://doi.org/10.3390/app9102161 - 27 May 2019

Cited by 9 | Viewed by 2496

Abstract

Manifold learning is a powerful dimensionality reduction tool for a hyperspectral image (HSI) classification to relieve the curse of dimensionality and to reveal the intrinsic low-dimensional manifold. However, a specific characteristic of HSIs, i.e., irregular spatial dependency, is not taken into consideration in [...] Read more.

Manifold learning is a powerful dimensionality reduction tool for a hyperspectral image (HSI) classification to relieve the curse of dimensionality and to reveal the intrinsic low-dimensional manifold. However, a specific characteristic of HSIs, i.e., irregular spatial dependency, is not taken into consideration in the method design, which can yield many spatially homogenous subregions in an HSI scence. Conventional manifold learning methods, such as a locality preserving projection (LPP), pursue a unified projection on the entire HSI, while neglecting the local homogeneities on the HSI manifold caused by those spatially homogenous subregions. In this work, we propose a novel multiscale superpixelwise LPP (MSuperLPP) for HSI classification to overcome the challenge. First, we partition an HSI into homogeneous subregions with a multiscale superpixel segmentation. Then, on each scale, subregion specific LPPs and the associated preliminary classifications are performed. Finally, we aggregate the classification results from all scales using a decision fusion strategy to achieve the final result. Experimental results on three real hyperspectral data sets validate the effectiveness of our method. Full article

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18 pages, 3063 KiB

Open AccessArticle

Establishment of a Numerical Model to Design an Electro-Stimulating System for a Porcine Mandibular Critical Size Defect

by Hendrikje Raben, Peer W. Kämmerer, Rainer Bader and Ursula van Rienen

Appl. Sci. 2019, 9(10), 2160; https://doi.org/10.3390/app9102160 - 27 May 2019

Cited by 20 | Viewed by 3975

Abstract

Electrical stimulation is a promising therapeutic approach for the regeneration of large bone defects. Innovative electrically stimulating implants for critical size defects in the lower jaw are under development and need to be optimized in silico and tested in vivo prior to application. [...] Read more.

Electrical stimulation is a promising therapeutic approach for the regeneration of large bone defects. Innovative electrically stimulating implants for critical size defects in the lower jaw are under development and need to be optimized in silico and tested in vivo prior to application. In this context, numerical modelling and simulation are useful tools in the design process. In this study, a numerical model of an electrically stimulated minipig mandible was established to find optimal stimulation parameters that allow for a maximum area of beneficially stimulated tissue. Finite-element simulations were performed to determine the stimulation impact of the proposed implant design and to optimize the electric field distribution resulting from sinusoidal low-frequency (

f = 20 Hz

) electric stimulation. Optimal stimulation parameters of the electrode length

h_{el} = 25 m m

and the stimulation potential

φ_{stim} = 0.5 V

were determined. These parameter sets shall be applied in future in vivo validation studies. Furthermore, our results suggest that changing tissue properties during the course of the healing process might make a feedback-controlled stimulation system necessary. Full article

(This article belongs to the Special Issue Biomaterials for Bone Tissue Engineering)

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(a) Computer tomographic pictures of the head of a minipig. To reduce unnecessary computational costs in the later simulations the upper part of the head has been removed in the modelling process. (b) CAD model of a defective minipig mandible and its surrounding tissues, equipped with an electro-stimulating implant. The critical size defect (region of interest) is highlighted in red. (c) Bipolar electro-stimulating implant consisting of stimulating electrode (“Electrode 1”), insulator and counter-electrode (“Electrode 2”). The parameters <math display="inline"><semantics> <msub> <mi>h</mi> <mi>el</mi> </msub> </semantics></math> and <math display="inline"><semantics> <msub> <mi>φ</mi> <mi>stim</mi> </msub> </semantics></math> are to be optimized. Full article ">Figure 2
Equivalent circuit model for the electrode–tissue interface. Full article ">Figure 3
Boundary conditions applied in the simulation model: We assigned Dirichlet boundary conditions to the surfaces of both electrodes (black), homogeneous Neumann boundary conditions to the surface of the skin (blue), and a floating potential boundary condition to the surface enclosing the defect (red). Full article ">Figure 4
(a) Simulated electric field norm <math display="inline"><semantics> <mrow> <mrow> <mo>|</mo> </mrow> <munder> <mi mathvariant="bold">E</mi> <mo>̲</mo> </munder> <mrow> <mo>|</mo> </mrow> </mrow> </semantics></math> in a slice through the electrically stimulated minipig mandible (<math display="inline"><semantics> <mrow> <msub> <mi>h</mi> <mi>el</mi> </msub> <mo>=</mo> <mn>25</mn> <mspace width="0.166667em"/> <mi mathvariant="normal">m</mi> <mi mathvariant="normal">m</mi> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi>φ</mi> <mi>stim</mi> </msub> <mo>=</mo> <mn>0.523</mn> <mspace width="0.166667em"/> <mi mathvariant="normal">V</mi> </mrow> </semantics></math>). Scale is bounded for field strengths between 5 and 70 <math display="inline"><semantics> <mi mathvariant="normal">V</mi> </semantics></math>/<math display="inline"><semantics> <mi mathvariant="normal">m</mi> </semantics></math> and the arrow length is normalized. (b) Region with beneficially (top, green) and overstimulated (bottom, red) tissue around the electro-stimulating implant. The depicted mesh on the mandible bone corresponds to the finite-element discretization used in the simulations. Full article ">Figure 5
Volume of under-, beneficially, and overstimulated tissue in the ROI at a stimulation amplitude of <math display="inline"><semantics> <mrow> <msub> <mi>φ</mi> <mi>stim</mi> </msub> <mo>=</mo> <mn>1</mn> <mspace width="0.166667em"/> <mi mathvariant="normal">V</mi> </mrow> </semantics></math> as a function of the electrode length <math display="inline"><semantics> <msub> <mi>h</mi> <mi>el</mi> </msub> </semantics></math>. Full article ">Figure 6
Impact of changing the electrical conductivity <math display="inline"><semantics> <msub> <mi>σ</mi> <mi>defect</mi> </msub> </semantics></math> in the defect domain on the volume of stimulated tissue and the current flowing through the electrodes. Full article ">

15 pages, 2532 KiB

Open AccessArticle

Influence of Time Delay in Signal Transmission on Synchronization between Two Coupled FitzHugh-Nagumo Neurons

by Bin Zhen, Zhenhua Li and Zigen Song

Appl. Sci. 2019, 9(10), 2159; https://doi.org/10.3390/app9102159 - 27 May 2019

Cited by 7 | Viewed by 2856

Abstract

In this paper, the energy method is employed to analytically investigate the influence of time delay in signal transmission on synchronization between two coupled FitzHugh-Nagumo (FHN) neurons. Unlike pre-existing methods that deal with synchronization problems, our major idea is to consider the change [...] Read more.

In this paper, the energy method is employed to analytically investigate the influence of time delay in signal transmission on synchronization between two coupled FitzHugh-Nagumo (FHN) neurons. Unlike pre-existing methods that deal with synchronization problems, our major idea is to consider the change rate of the energy of the synchronization error system, since the original system’s synchronization is equivalent to the disappearance of the energy of the error system. In rewriting the original coupled system in the corresponding energy coordinates based on the energy method, we find that the change rate of energy of the error system can be divided into two parts (periodic and non-periodic). The synchronization criterion for the original system can then be obtained by letting the non-periodic part of the change rate of the energy be less than zero. The correctness of the analysis is illustrated with numerical simulations. Our analytical results show that time delay in signal transmission has very significant effects on the synchronization between two FHN neurons. If the time delay in signal transmission is not taken into account in the two coupled FHN neurons, synchronous spikes cannot be achieved in the system for any given coupling strength. By adjusting the value of the time delay in signal transmission, the neural system can freely switch between neural rest and synchronous spikes. This means that time delay in signal transmission is crucial for the occurrence of synchronous spikes in the FHN neural system, which contributes to our understanding of the interaction between neurons. We analytically show the influence of the time delay on the synchronization between two FHN neurons, which was seldom considered by other researchers. Full article

(This article belongs to the Section Applied Biosciences and Bioengineering)

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11 pages, 1237 KiB

Open AccessReview

Toward Long-Term Implantable Glucose Biosensors for Clinical Use

by Yun Jung Heo and Seong-Hyok Kim

Appl. Sci. 2019, 9(10), 2158; https://doi.org/10.3390/app9102158 - 27 May 2019

Cited by 23 | Viewed by 7471

Abstract

Continuous glucose monitoring (CGM) sensors have led a paradigm shift to painless, continuous, zero-finger pricking measurement in blood glucose monitoring. Recent electrochemical CGM sensors have reached two-week lifespans and no calibration with clinically acceptable accuracy. The system with the recent CGM sensors is [...] Read more.

Continuous glucose monitoring (CGM) sensors have led a paradigm shift to painless, continuous, zero-finger pricking measurement in blood glucose monitoring. Recent electrochemical CGM sensors have reached two-week lifespans and no calibration with clinically acceptable accuracy. The system with the recent CGM sensors is identified as an “integrated glucose monitoring system,” which can replace finger-pricking glucose-testing for diabetes treatment decisions. Although such innovation has brought CGM technology closer to realizing the artificial pancreas, discomfort and infection problems have arisen from short lifespans and open wounds. A fully implantable sensor with a longer-term lifespan (90 days) is considered as an alternative CGM sensor with high comfort and low running cost. However, it still has barriers, including surgery for applying and replacing and frequent calibration. If technical refinement is conducted (e.g., stability and reproducibility of sensor fabrication), fully implantable, long-term CGM sensors can open the new era of continuous glucose monitoring. Full article

(This article belongs to the Special Issue Biomaterials and Biofabrication)

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14 pages, 2037 KiB

Open AccessReview

Overview on the Evolution of Laser Welding of Vascular and Nervous Tissues

by Diogo Francisco Gomes, Ivan Galvão and Maria Amélia Ramos Loja

Appl. Sci. 2019, 9(10), 2157; https://doi.org/10.3390/app9102157 - 27 May 2019

Cited by 11 | Viewed by 5536

Abstract

Laser welding presents a core position in the health sector. This process has had an outstanding impact on the surgical procedures from many medical areas, such as on vascular and nervous surgeries. The aim of the present research is to present an overview [...] Read more.

Laser welding presents a core position in the health sector. This process has had an outstanding impact on the surgical procedures from many medical areas, such as on vascular and nervous surgeries. The aim of the present research is to present an overview on the evolution of laser welding of vascular and nervous tissues. These surgeries present many advantages, such as an absence of foreign-body reactions and aneurysms and good tensile strengths. However, despite the sutureless nature of the process, complementary sutures have been applied to support the procedure success. An important concern in vascular and nervous laser welding is the thermal damage. The development of temperature-controlled feedback systems has reduced this concern with a very precise control of the laser parameters. The bonding strength of vascular and nerve laser welds can be enhanced with the application of solder solutions, bonding materials, and laser-activated dyes. Alternative techniques to laser welding, such as photochemical tissue bonding and electrosurgical high-frequency technologies, have also been tested for vascular and nervous repairs. Full article

(This article belongs to the Special Issue New Frontiers of Laser Welding Technology)

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Schematics of laser welding of a nervous tissue [<a href="#B40-applsci-09-02157" class="html-bibr">40</a>]. Full article ">Figure 2
Instrumentation for preloaded longitudinal compression: (a) Vessel clamp device (prototype); (b) Procedure of preloaded longitudinal compression [<a href="#B48-applsci-09-02157" class="html-bibr">48</a>]. Full article ">Figure 3
Visual identification scores and adequate laser-welding end point [<a href="#B45-applsci-09-02157" class="html-bibr">45</a>,<a href="#B56-applsci-09-02157" class="html-bibr">56</a>]. Full article ">Figure 4
Schematics of laser welding of a nervous tissue, with the application of a solder and a light absorbing dye [<a href="#B40-applsci-09-02157" class="html-bibr">40</a>]. Full article ">Figure 5
Transverse cross-section of an artery repaired by laser welding, with the application of a semi-solid solder solution [<a href="#B47-applsci-09-02157" class="html-bibr">47</a>]. Full article ">Figure 6
Schematics of the laser-assisted vessel soldering [<a href="#B51-applsci-09-02157" class="html-bibr">51</a>]. Full article ">

14 pages, 3048 KiB

Open AccessFeature PaperArticle

The Effect of Elevated Temperatures on the TRM-to-Masonry Bond: Comparison of Normal Weight and Lightweight Matrices

by Paraskevi D. Askouni, Catherine (Corina) G. Papanicolaou and Michael I. Kaffetzakis

Appl. Sci. 2019, 9(10), 2156; https://doi.org/10.3390/app9102156 - 27 May 2019

Cited by 15 | Viewed by 2720

Abstract

Textile Reinforced Mortar (TRM) is a composite material that has already been successfully used as an externally bonded strengthening means of existing structures. The bond of TRM with various substrates is of crucial importance for determining the degree of exploitation of the textile. [...] Read more.

Textile Reinforced Mortar (TRM) is a composite material that has already been successfully used as an externally bonded strengthening means of existing structures. The bond of TRM with various substrates is of crucial importance for determining the degree of exploitation of the textile. However, little is known on the effect of elevated/high temperatures on the TRM-to-substrate bond characteristics while relevant testing protocols are also lacking. This study focuses on the experimental assessment of the TRM-to-masonry bond after exposure of masonry wallettes unilaterally furnished with TRM strips at 120 °C and 200 °C for 1 h. The shear bond tests on cooled-down specimens were carried out using the single-lap/single-prism set-up. Two TRM systems were investigated sharing the same type of textile, which is a dry AR glass fiber one (either in a single-layer or in a double-layer configuration) and different matrices: one normal weight (TRNM) and another lightweight (TRLM) of equal compressive strengths. At control conditions (non-heated specimens) and after exposure at a nominal air temperature of 120 °C, both single-layer TRM systems exhibited similar bond capacities. After exposure at a nominal air temperature of 200 °C single-layer and double-layer TRNM overlays outperformed their TRLM counterparts. A critical discussion is based on phenomenological evidence and measured response values. Full article

(This article belongs to the Special Issue Textile Reinforced Cement Composites: New Insights in Structural and Material Engineering)

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Axial tensile stress versus axial tensile strain curves of: (a) TRNM (Textile Reinforced Normal Weight Mortar) and (b) TRLM (Textile Reinforced Lightweight Mortar) coupons (stress is calculated by dividing with the load-aligned fibers’ cross section). Full article ">Figure 2
Single-lap/single-prism shear bond test set-up. Full article ">Figure 3
Time history of specimens’ preparation and treatment. Full article ">Figure 4
Insulated specimen (instrumented with thermocouples): (a) side view and (b) inside the electrical furnace; (K-type thermocouple: close to Loaded End, TKLE; close to Free End, TKFE; on the strip’s surface, TKM; close to specimen’s surface, TKA) Full article ">Figure 5
Specimen at failure. Full article ">Figure 6
Thermocouples’ temperature profiles for representative specimens: (a) T120S1L03, (b) T200S1L03, and (c) T200S2L02. Full article ">Figure 7
(a) Maximum textile axial stress, σmax, and corresponding (b) relative displacement, dr,max, and (c) slip, smax, versus nominal exposure temperature. Full article ">Figure 8
Response curves of representative specimens reinforced with: (a) TRNM and (b) TRLM overlays. Full article ">

13 pages, 1295 KiB

Open AccessArticle

Ultra-Low Interfacial Tension Foam System for Enhanced Oil Recovery

by Qi Liu, Shuangxing Liu, Dan Luo and Bo Peng

Appl. Sci. 2019, 9(10), 2155; https://doi.org/10.3390/app9102155 - 27 May 2019

Cited by 21 | Viewed by 4173

Abstract

The liquid phase of foam systems plays a major role in improving the fluidity of oil, by reducing oil viscosity and stripping oil from rock surfaces during foam-flooding processes. Improving the oil displacement capacity of the foam’s liquid phase could lead to significant [...] Read more.

The liquid phase of foam systems plays a major role in improving the fluidity of oil, by reducing oil viscosity and stripping oil from rock surfaces during foam-flooding processes. Improving the oil displacement capacity of the foam’s liquid phase could lead to significant improvement in foam-flooding effects. Oil-liquid interfacial tension (IFT) is an important indicator of the oil displacement capacity of a liquid. In this study, several surfactants were used as foaming agents, and polymers were used as foam stabilizers. Foaming was induced using a Waring blender stirring method. Foam with an oil-liquid IFT of less than 10–3 mN/m was prepared after a series of adjustments to the liquid composition. This study verified the possibility of a foam system with both an ultra-low oil-liquid IFT and high foaming properties. Our results provide insight into a means of optimizing foam fluids for enhanced oil recovery. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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12 pages, 942 KiB

Open AccessArticle

Simple Degree-of-Freedom Modeling of the Random Fluctuation Arising in Human–Bicycle Balance

by Katsutoshi Yoshida, Keishi Sato and Yoshikazu Yamanaka

Appl. Sci. 2019, 9(10), 2154; https://doi.org/10.3390/app9102154 - 27 May 2019

Cited by 5 | Viewed by 3016

Abstract

In this study, we propose a new simple degree-of-freedom fluctuation model that accurately reproduces the probability density functions (PDFs) of human–bicycle balance motions as simply as possible. First, we measure the time series of the roll angular displacement and velocity of human–bicycle balance [...] Read more.

In this study, we propose a new simple degree-of-freedom fluctuation model that accurately reproduces the probability density functions (PDFs) of human–bicycle balance motions as simply as possible. First, we measure the time series of the roll angular displacement and velocity of human–bicycle balance motions and construct their PDFs. Next, using these PDFs as training data, we identify the model parameters by means of particle swarm optimization; in particular, we minimize the Kolmogorov–Smirnov distance between the human PDFs from the participants and the PDFs simulated by our model. The resulting PDF fitnesses were over

98.7 %

for all participants, indicating that our simulated PDFs were in close agreement with human PDFs. Furthermore, the Kolmogorov–Smirnov statistical hypothesis testing was applied to the resulting human–bicycle fluctuation model, showing that the measured time responses were much better supported by our model than the Gaussian distribution. Full article

(This article belongs to the Special Issue Vibration-Based Structural Health Monitoring)

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13 pages, 2578 KiB

Open AccessArticle

Classification of Marine Vessels with Multi-Feature Structure Fusion

by Erhu Zhang, Kelu Wang and Guangfeng Lin

Appl. Sci. 2019, 9(10), 2153; https://doi.org/10.3390/app9102153 - 27 May 2019

Cited by 20 | Viewed by 3729

Abstract

The classification of marine vessels is one of the important problems of maritime traffic. To fully exploit the complementarity between different features and to more effectively identify marine vessels, a novel feature structure fusion method based on spectral regression discriminant analysis (SF-SRDA) was [...] Read more.

The classification of marine vessels is one of the important problems of maritime traffic. To fully exploit the complementarity between different features and to more effectively identify marine vessels, a novel feature structure fusion method based on spectral regression discriminant analysis (SF-SRDA) was proposed. Firstly, we selected the different convolutional neural network features that better describe the characteristics of ships, and constructed the features based on graphs by the similarity metric. Then we weighed the concatenate multi-feature and fused their structures according to the linear relationship assumption. Finally, we constructed the optimization formula to solve the fusion features and structure by using spectral regression discriminant analyses. Experiments on the VAIS dataset show that the proposed SF-SRDA method can reduce the feature dimension from the original 102,400 dimensions to 5 dimensions, that the classification accuracy of visible images can reach 87.60%, and that that of the infrared image can reach 74.68% at daytime. The experimental results demonstrate that the proposed method can not only extract the optimal features from the original redundant feature space, but also greatly reduce the dimensions of the feature. Furthermore, the classification performance of SF-SRDA also gets a promising result. Full article

(This article belongs to the Special Issue Multimodal Deep Learning Methods for Video Analytics)

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13 pages, 6011 KiB

Open AccessArticle

Modeling and Analysis of the Influence of an Edge Filter on the Combining Efficiency and Beam Quality of a 10-kW-Class Spectral Beam-Combining System

by Jun Ma, Fan Chen, Cong Wei and Rihong Zhu

Appl. Sci. 2019, 9(10), 2152; https://doi.org/10.3390/app9102152 - 27 May 2019

Cited by 6 | Viewed by 3055

Abstract

Filter-based spectral beam combining (FSBC) is a promising power-scaling concept for high-power, broad-linewidth fiber lasers, as it relaxes the requirements for linewidth control and also the sizes of the individual beams. As the combining element in the FSBC system, the steep-edge filter plays [...] Read more.

Filter-based spectral beam combining (FSBC) is a promising power-scaling concept for high-power, broad-linewidth fiber lasers, as it relaxes the requirements for linewidth control and also the sizes of the individual beams. As the combining element in the FSBC system, the steep-edge filter plays a major role in achievement of the combining efficiency and the beam quality. In this case, we combine the uncorrelated surface roughness model and the combining efficiency model, and we conduct a comprehensive analysis of the effects of surface roughness, thickness error, and incident angle on the filter’s optical properties and the combining efficiency, in order to determine the optimal configuration for the laser beam-combining system. The simulation results show a good agreement with the measured ones. Meanwhile, through the adoption of the angular spectrum theory, this paper has also conducted a preliminary analysis of the influence of the combining elements on the quality of the combined beam, and some theoretical instructions on the future design of the spectral beam-combining system are provided. Full article

(This article belongs to the Section Optics and Lasers)

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16 pages, 2730 KiB

Open AccessArticle

Multi-Objective Defocus Robust Source and Mask Optimization Using Sensitive Penalty

by Pengzhi Wei, Yanqiu Li, Tie Li, Naiyuan Sheng, Enze Li and Yiyu Sun

Appl. Sci. 2019, 9(10), 2151; https://doi.org/10.3390/app9102151 - 27 May 2019

Cited by 7 | Viewed by 2579

Abstract

The continuous decrease in the size of lithographic technology nodes has led to the development of source and mask optimization (SMO) and also to the control of defocus becoming stringent in the actual lithography process. Due to multi-factor impact, defocusing is always changeable [...] Read more.

The continuous decrease in the size of lithographic technology nodes has led to the development of source and mask optimization (SMO) and also to the control of defocus becoming stringent in the actual lithography process. Due to multi-factor impact, defocusing is always changeable and uncertain in the real exposure process. But conventional SMO assumes the lithography system is ideal, which only compensates the optical proximity effect (OPE) in the best focus plane. Therefore, to solve the inverse lithography problem with more uniformity of pattern in different defocus variations, we proposed a defocus robust SMO (DRSMO) approach that is driven by a defocus sensitivity penalty function for the first time. This multi-objective optimization samples a wide range of defocus disturbances and it can be proceeded by the mini-batch gradient descent (MBGD) algorithm effectively. The simulation results showed that a more robust defocus source and mask can be designed through DRSMO optimization. The defocus sensitivity factor s_β maximally decreased 63.5% compared to conventional SMO, and due to the low error sensitivity and the depth of defocus (DOF), the process window (PW) was further enlarged effectively. Compared to conventional SMO, the exposure latitude (EL) maximally increased from 4.5% to 10.5% and DOF maximally increased 54.5% (EL = 5%), which proved the validity of the DRSMO method in improving the focusing performance. Full article

(This article belongs to the Section Optics and Lasers)

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12 pages, 1933 KiB

Open AccessFeature PaperArticle

Plasma-Activation of Larger Liquid Volumes by an Inductively-Limited Discharge for Antimicrobial Purposes

by Michael Schmidt, Veronika Hahn, Beke Altrock, Torsten Gerling, Ioana Cristina Gerber, Klaus-Dieter Weltmann and Thomas von Woedtke

Appl. Sci. 2019, 9(10), 2150; https://doi.org/10.3390/app9102150 - 27 May 2019

Cited by 31 | Viewed by 4030

Abstract

A new configuration of a discharge chamber and power source for the treatment of up to 1 L of liquid is presented. A leakage transformer, energizing two metal electrodes positioned above the liquid, limits the discharge current inductively by utilizing the weak magnetic [...] Read more.

A new configuration of a discharge chamber and power source for the treatment of up to 1 L of liquid is presented. A leakage transformer, energizing two metal electrodes positioned above the liquid, limits the discharge current inductively by utilizing the weak magnetic coupling between the primary and secondary coils. No additional means to avoid arcing (electric short-circuiting), e.g., dielectric barriers or resistors, are needed. By using this technique, exceeding the breakdown voltage leads to the formation of transient spark discharges, producing non-thermal plasma (NTP). These discharges effected significant changes in the properties of the treated liquids (distilled water, physiological saline solution, and tap water). Considerable concentrations of nitrite and nitrate were detected after the plasma treatment. Furthermore, all tested liquids gained strong antibacterial efficacy which was shown by inactivating suspended Escherichia coli and Staphylococcus aureus. Plasma-treated tap water had the strongest effect, which is shown for the first time. Additionally, the pH-value of tap water did not decrease during the plasma treatment, and its conductivity increased less than for the other tested liquids. Full article

(This article belongs to the Special Issue Plasma Technology for Biomedical Applications)

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15 pages, 3964 KiB

Open AccessArticle

Enhanced Application of Principal Component Analysis in Machine Learning for Imputation of Missing Traffic Data

by Yoon-Young Choi, Heeseung Shon, Young-Ji Byon, Dong-Kyu Kim and Seungmo Kang

Appl. Sci. 2019, 9(10), 2149; https://doi.org/10.3390/app9102149 - 26 May 2019

Cited by 13 | Viewed by 3863

Abstract

Missing value imputation approaches have been widely used to support and maintain the quality of traffic data. Although the spatiotemporal dependency-based approaches can improve the imputation performance for large and continuous missing patterns, additionally considering traffic states can lead to more reliable results. [...] Read more.

Missing value imputation approaches have been widely used to support and maintain the quality of traffic data. Although the spatiotemporal dependency-based approaches can improve the imputation performance for large and continuous missing patterns, additionally considering traffic states can lead to more reliable results. In order to improve the imputation performances further, a section-based approach is also needed. This study proposes a novel approach for identifying traffic-states of different spots of road sections that comprise, namely, a section-based traffic state (SBTS), and determining their spatiotemporal dependencies customized for each SBTS, for missing value imputations. A principal component analysis (PCA) was employed, and angles obtained from the first principal component were used to identify the SBTSs. The pre-processing was combined with a support vector machine for developing the imputation model. It was found that the segmentation of the SBTS using the angles and considering the spatiotemporal dependency for each state by the proposed approach outperformed other existing models. Full article

(This article belongs to the Section Civil Engineering)

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Speed contour and <math display="inline"><semantics> <mrow> <mi>A</mi> <mi>n</mi> <msub> <mi>g</mi> <mi>t</mi> </msub> </mrow> </semantics></math> plots for the numerical example. Full article ">Figure 2
Study area in Korean freeway. (a) Geographical information. (b) Vehicle detection system (VDS) information. Full article ">Figure 3
Speed contour and <math display="inline"><semantics> <mrow> <mi>A</mi> <mi>n</mi> <msub> <mi>g</mi> <mi>t</mi> </msub> </mrow> </semantics></math> plots for empirical data on 3 March 2016. Full article ">Figure 4
<math display="inline"><semantics> <mrow> <mi>A</mi> <mi>n</mi> <msub> <mi>g</mi> <mi>t</mi> </msub> </mrow> </semantics></math> and average speed plots on 12 March 2016. Full article ">Figure 5
Flow-speed and occupancy-flow plots at VDS 4 on March 12 2016. (a) Classified by <math display="inline"><semantics> <mrow> <mi>A</mi> <mi>n</mi> <msub> <mi>g</mi> <mi>t</mi> </msub> </mrow> </semantics></math>. (b) Classified by average speed. Full article ">Figure 6
Spatiotemporal dependence among variables (a) Section-based traffic state (SBTS) I (b) SBTS II (c) SBTS III. Full article ">Figure 7
Traffic speed profile of real and predicted data by ANN and proposed model. Full article ">

23 pages, 2172 KiB

Open AccessArticle

Identifying Brain Abnormalities with Schizophrenia Based on a Hybrid Feature Selection Technology

by Chen Qiao, Lujia Lu, Lan Yang and Paul J. Kennedy

Appl. Sci. 2019, 9(10), 2148; https://doi.org/10.3390/app9102148 - 26 May 2019

Cited by 8 | Viewed by 4280

Abstract

Many medical imaging data, especially the magnetic resonance imaging (MRI) data, usually have a small sample size, but a large number of features. How to reduce effectively the data dimension and locate accurately the biomarkers from such kinds of data are quite crucial [...] Read more.

Many medical imaging data, especially the magnetic resonance imaging (MRI) data, usually have a small sample size, but a large number of features. How to reduce effectively the data dimension and locate accurately the biomarkers from such kinds of data are quite crucial for diagnosis and further precision medicine. In this paper, we propose a hybrid feature selection method based on machine learning and traditional statistical approaches and explore the brain abnormalities of schizophrenia by using the functional and structural MRI data. The results show that the abnormal brain regions are mainly distributed in the supramarginal gyrus, cingulate gyrus, frontal gyrus, precuneus and caudate, and the abnormal functional connections are related to the caudate nucleus, insula and rolandic operculum. In addition, some complex network analyses based on graph theory are utilized on the functional connection data, and the results demonstrate that the located abnormal functional connections in brain can distinguish schizophrenia patients from healthy controls. The identified abnormalities in brain with schizophrenia by the proposed hybrid feature selection method show that there do exist some abnormal brain regions and abnormal disruption of the network segregation and network integration for schizophrenia, and these changes may lead to inaccurate and inefficient information processing and synthesis in the brain, which provide further evidence for the cognitive dysmetria of schizophrenia. Full article

(This article belongs to the Special Issue Optical Methods for Tissue Diagnostics)

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13 pages, 1501 KiB

Open AccessArticle

Assessing the Benefits of Battery Energy Storage Systems for Frequency Regulation, Based on Electricity Market Price Forecasting

by Eunjung Lee and Jinho Kim

Appl. Sci. 2019, 9(10), 2147; https://doi.org/10.3390/app9102147 - 26 May 2019

Cited by 5 | Viewed by 3182

Abstract

In electricity markets, energy storage systems (ESSs) have been widely used to regulate frequency in power system operations. Frequency regulation (F/R) relates to the short-term reserve power used to balance the real-time mismatch of supply and demand. Every alternating current power system has [...] Read more.

In electricity markets, energy storage systems (ESSs) have been widely used to regulate frequency in power system operations. Frequency regulation (F/R) relates to the short-term reserve power used to balance the real-time mismatch of supply and demand. Every alternating current power system has its own unique standard frequency level, and frequency variation occurs whenever there is a mismatch of supply and demand. To cope with frequency variation, generating units—particularly base-loader generators—reduce their power outputs to a certain level, and the reduced generation outputs are used as a generation reserve whenever frequency variation occurs in the power systems. ESSs have recently been implemented as an innovative means of providing the F/R reserve previously provided by base-loader generators, because they are much faster in responding to frequency variation than conventional generators. We assess the economic benefits of ESSs for F/R, based on a new forecast of long-term electricity market price and real power system operation characteristics. For this purpose, we present case studies with respect to the South Korean electricity market as well as simulation results featuring key variables, along with their implications vis-à-vis electricity market operations. Full article

(This article belongs to the Special Issue State-of-the-Art Renewable Energy in Korea)

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11 pages, 2715 KiB

Open AccessArticle

Optimal Measurement Speed and Its Determination Method in the Transmission Precision Evaluation of Precision Reducers

by Hang Xu, Zhaoyao Shi, Bo Yu and Hui Wang

Appl. Sci. 2019, 9(10), 2146; https://doi.org/10.3390/app9102146 - 26 May 2019

Cited by 18 | Viewed by 2816

Abstract

Transmission error is the key index for characterizing the transmission precision of precision reducers, and its accurate measurement is significant for the precision evaluation of precision reducers. Transmission error is generally measured under the conditions of zero-load and low speed. However, low speed [...] Read more.

Transmission error is the key index for characterizing the transmission precision of precision reducers, and its accurate measurement is significant for the precision evaluation of precision reducers. Transmission error is generally measured under the conditions of zero-load and low speed. However, low speed is a general concept and there is no general standard of measurement speed or solid scientific basis. Therefore, it is difficult to obtain consistent transmission precision evaluation results for the same precision reducer. The concept of optimal measurement speed in the transmission precision evaluation of precision reducers was put forward in order to reduce the influence of measurement speed. The determination method of optimal measurement speed was proposed and the calculation model of the optimal measurement speed was established, according to the Stribeck friction model of precision reducers. Taking a certain type of RV reducer as an example, the transmission error measurement experiments were carried out under different speeds. The friction torque of the RV reducer and the peak-to-peak value of the measured transmission error were the least under the optimal measurement speed. The influence of speed on the measurement results can be effectively reduced. The determination of optimal measurement speed of transmission errors could improve the measurement precision of the transmission errors for the objective evaluation of transmission precision of precision reducers. Full article

(This article belongs to the Section Mechanical Engineering)

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13 pages, 5726 KiB

Open AccessArticle

High Spatial Resolution Three-Dimensional Imaging Static Unitary Detector-Based Laser Detection and Ranging Sensor

by Hyeon-June Kim, Eun-Gyu Lee, Han-Woong Choi and Choul-Young Kim

Appl. Sci. 2019, 9(10), 2145; https://doi.org/10.3390/app9102145 - 26 May 2019

Viewed by 3164

Abstract

This paper presents a static unitary detector (STUD)-based laser detection and ranging (LADAR) sensor with a 16-to-1 transimpedance-combining amplifier for high spatial resolution three-dimensional (3-D) applications. In order to readout the large size of a photodetector for better results of 3-D information without [...] Read more.

This paper presents a static unitary detector (STUD)-based laser detection and ranging (LADAR) sensor with a 16-to-1 transimpedance-combining amplifier for high spatial resolution three-dimensional (3-D) applications. In order to readout the large size of a photodetector for better results of 3-D information without any reduction of the bandwidth, the partitioning photosensitive cell method is embedded in a 16-to-1 transimpedance-combining amplifier. The effective number of partitioning photosensitive cells and signal-combining stages are selected based on the analysis of the partitioning photosensitive cell method for the optimum performance of a transimpedance-combining amplifier. A prototype chip is fabricated in a 0.18-μm CMOS technology. The input referred noise is 41.9 pA/√Hz with a bandwidth of 230 MHz and a transimpedance gain of 70.4 dB·Ω. The total power consumption of the prototype chip is approximately 86 mW from a 1.8-V supply, and the TICA consumes approximately 15.4 mW of it. Full article

(This article belongs to the Special Issue LiDAR and Time-of-flight Imaging)

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16 pages, 1691 KiB

Open AccessArticle

Increased Anti-Inflammatory Effects on LPS-Induced Microglia Cells by Spirulina maxima Extract from Ultrasonic Process

by Woon Yong Choi, Jae-Hun Sim, Jung-Youl Lee, Do Hyung Kang and Hyeon Yong Lee

Appl. Sci. 2019, 9(10), 2144; https://doi.org/10.3390/app9102144 - 26 May 2019

Cited by 15 | Viewed by 3787

Abstract

The Spirulina maxima exact from a non-thermal ultrasonic process (UE) contains 17.5 mg/g of total chlorophyll, compared to 6.24 mg/g of chlorophyll derived from the conventional 70% ethanol extraction at 80 °C for 12 h (EE). The UE also showed relatively low cytotoxicity [...] Read more.

The Spirulina maxima exact from a non-thermal ultrasonic process (UE) contains 17.5 mg/g of total chlorophyll, compared to 6.24 mg/g of chlorophyll derived from the conventional 70% ethanol extraction at 80 °C for 12 h (EE). The UE also showed relatively low cytotoxicity against murine microglial cells (BV-2) and inhibited the production of the inflammatory mediators, NO and PGE₂. The UE also effectively suppresses both mRNA expression and the production of pro-inflammatory cytokines, such as TNF-α, IL-6 and IL-1β, in a concentration-dependent manner. Notably, TNF-α gene and protein production were most strongly down-regulated, while IL-6 was the least affected by all ranges of treatment concentrations. This work first demonstrated a quantitative correlation between mRNA expression and the production of cytokines, showing that suppression of TNF-α gene expression was most significantly correlated with its secretion. These results clearly proved that the anti-inflammatory effects of Spirulina extract from a nonthermal ultrasonic process, which yielded high concentrations of intact forms of chlorophylls, were increased two-fold compared to those of conventional extracts processed at high temperature. Full article

(This article belongs to the Special Issue Eco-Novel Food and Feed)

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20 pages, 1939 KiB

Open AccessArticle

The Study on the Cultivable Microbiome of the Aquatic Fern Azolla Filiculoides L. as New Source of Beneficial Microorganisms

by Artur Banach, Agnieszka Kuźniar, Radosław Mencfel and Agnieszka Wolińska

Appl. Sci. 2019, 9(10), 2143; https://doi.org/10.3390/app9102143 - 26 May 2019

Cited by 14 | Viewed by 6288

Abstract

The aim of the study was to determine the still not completely described microbiome associated with the aquatic fern Azolla filiculoides. During the experiment, 58 microbial isolates (43 epiphytes and 15 endophytes) with different morphologies were obtained. We successfully identified 85% of [...] Read more.

The aim of the study was to determine the still not completely described microbiome associated with the aquatic fern Azolla filiculoides. During the experiment, 58 microbial isolates (43 epiphytes and 15 endophytes) with different morphologies were obtained. We successfully identified 85% of microorganisms and assigned them to 9 bacterial genera: Achromobacter, Bacillus, Microbacterium, Delftia, Agrobacterium, and Alcaligenes (epiphytes) as well as Bacillus, Staphylococcus, Micrococcus, and Acinetobacter (endophytes). We also studied an A. filiculoides cyanobiont originally classified as Anabaena azollae; however, the analysis of its morphological traits suggests that this should be renamed as Trichormus azollae. Finally, the potential of the representatives of the identified microbial genera to synthesize plant growth-promoting substances such as indole-3-acetic acid (IAA), cellulase and protease enzymes, siderophores and phosphorus (P) and their potential of utilization thereof were checked. Delftia sp. AzoEpi7 was the only one from all the identified genera exhibiting the ability to synthesize all the studied growth promoters; thus, it was recommended as the most beneficial bacteria in the studied microbiome. The other three potentially advantageous isolates (Micrococcus sp. AzoEndo14, Agrobacterium sp. AzoEpi25 and Bacillus sp. AzoEndo3) displayed 5 parameters: IAA (excluding Bacillus sp. AzoEndo3), cellulase, protease, siderophores (excluding Micrococcus sp. AzoEndo14), as well as mineralization and solubilization of P (excluding Agrobacterium sp. AzoEpi25). Full article

(This article belongs to the Section Applied Biosciences and Bioengineering)

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Appl. Sci., Volume 9, Issue 10 (May-2 2019) – 207 articles

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