bluuebunny/crossref_metadata_2025 huggingface dataset:
Pore Solution Chemistry of Calcium Sulfoaluminate Cement and Its Effects on Steel Passivation
Authors: Wang Lingbo , Zhan Shulin , Tang Xudong , Xu Qiang , Qian Kuangliang
Published: March 2019

Calcium sulfoaluminate cement (CSA) is a type of low-CO2 binder which has been widely applied in the production of concrete. To investigate the protection capability offered by CSA to keep steel from corrosion, the pore solution chemistry of CSA on steel passivation was investigated in this study. The pore solution of CSA pastes, extracted by an ex situ leaching method, was studied and compared with ordinary Portland cement (OPC). The results show that the alkalinity of the CSA pore solution is not only much lower than that of OPC, but also that a new type of ion, Al(OH)4−, and high concentration of SO42− were detected in the liquid phase of CSA. Based on pore solution chemistry analysis, a simulated pore solution (SPS) system was designed to assess the comprehensive impact of alkalinity and ion composition, featured as properties of CSA, on steel passivation. The results of the corrosion potential evolution highlight the importance of alkalinity in passivation. SO42− can cause depassivation when there is not enough hydroxyl, but Al(OH)4− is able to maintain the alkalinity of the system, enhancing the stability of the passive film.
Spatial Uncertainty Modeling for Surface Roughness of Additively Manufactured Microstructures via Image Segmentation
Authors: Kim Namjung , Yang Chen , Lee Howon , Aluru Narayana R.
Published: March 2019

Despite recent advances in additive manufacturing (AM) that shifts the paradigm of modern manufacturing by its fast, flexible, and affordable manufacturing method, the achievement of high-dimensional accuracy in AM to ensure product consistency and reliability is still an unmet challenge. This study suggests a general method to establish a mathematical spatial uncertainty model based on the measured geometry of AM microstructures. Spatial uncertainty is specified as the deviation between the planned and the actual AM geometries of a model structure, high-aspect-ratio struts. The detailed steps of quantifying spatial uncertainties in the AM geometry are as follows: (1) image segmentation to extract the sidewall profiles of AM geometry; (2) variability-based sampling; (3) Gaussian process modeling for spatial uncertainty. The modeled spatial uncertainty is superimposed in the CAD geometry and finite element analysis is performed to quantify its effect on the mechanical behavior of AM struts with different printing angles under compressive loading conditions. The results indicate that the stiffness of AM struts with spatial uncertainty is reduced to 70% of the stiffness of CAD geometry and the maximum von Mises stress under compressive loading is significantly increased by the spatial uncertainties. The proposed modeling framework enables the high fidelity of computer-based predictive tools by seamlessly incorporating spatial uncertainties from digital images of AM parts into a traditional finite element model. It can also be applied to parts produced by other manufacturing processes as well as other AM techniques.
Flutter and Divergence Instability of Axially-Moving Nanoplates Resting on a Viscoelastic Foundation
Authors: Duan Jingbo , Zhang Dapeng , Wang Wenjie
Published: March 2019

Moving nanosystems often rest on a medium exhibiting viscoelastic behavior in engineering applications. The moving velocity and viscoelastic parameters of the medium usually have an interacting impact on the mechanical properties of nanostructures. This paper investigates the dynamic stability of an axially-moving nanoplate resting on a viscoelastic foundation based on the nonlocal elasticity theory. Firstly, the governing partial equations subject to appropriate boundary conditions are derived through utilizing the Hamilton’s principle with the axial velocity, viscoelastic foundation, nonlocal effect and biaxial loadings taken into consideration. Subsequently, the characteristic equation describing the dynamic characteristics is obtained by employing the Galerkin strip distributed transfer function method. Then, complex frequency curves for the nanoplate are displayed graphically and the effects of viscoelastic foundation parameters, small-scale parameters and axial forces on divergence instability and coupled-mode flutter are analyzed, which show that these parameters play a crucial role in affecting nanostructural instability. The presented results benefit the designation of axially-moving graphene nanosheets or other plate-like nanostructures resting on a viscoelastic foundation.
Efficient Characterization of Macroscopic Composite Cement Mortars with Various Contents of Phase Change Material
Authors: Zalewski Laurent , Franquet Erwin , Gibout Stéphane , Tittelein Pierre , Defer Didier
Published: March 2019

The determination of both the thermal and thermodynamical properties of a composite material containing phase change material is done thanks to an inverse method, which combines experimental measurements and numerical computations. Given first an in-house experiment, which allows us to test samples at a macroscopic scale (i.e., close to the real conditions) and to set various types of thermal stresses, and secondly the simulation of the corresponding thermal behavior, relying on an accurate thermodynamical modeling and taking into account the real operating parameters (e.g., thermal contact resistances and non-symmetric heat fluxes on each side), it is possible to characterize the solid and liquid thermal conductivities and heat capacities, as well as the temperature range associated with a non-isothermal phase transition and the associated latent heat. The specificity of the present approach is to allow, in a single step, a characterization of all the involved thermo-physical parameters that are usually required in simulation tools (e.g., EnergyPlus…). Moreover, the hitherto studies dealing with repeatability and uncertainties of the enthalpy characterization are generally very scant and not encountered very often or only with qualitative assessments. This is a clear caveat, especially when considering any system design. Therefore, for the first time ever, the present paper pays a special attention to the repeatability of the identification method and studies the scedasticity of the results, that is to say the deviations of the determined enthalpy curves, not only from a qualitative point of view but also by proposing quantitative arguments. Finally, the results are very promising since the agreement between all trials is excellent, the maximum error for all parameters being lower than 4%. This is far below the current quality thresholds admitted when characterizing the enthalpy of a phase change material.
Effect of Bonding Temperature on Microstructure and Mechanical Properties during TLP Bonding of GH4169 Superalloy
Authors: He Qing , Zhu Dongdong , Dong Duo , Xu Mengjia , Wang Anpeng , Sun Qiancheng
Published: March 2019

The effect of bonding temperature on the microstructure and mechanical properties of transient liquid phase (TLP) joints of GH4169 superalloy was investigated. Joining processes were carried out at 1040–1100 °C for 30 min using BNi-2 solder paste. The results showed that three distinct microstructural zones were formed in the joint region: an athermal solidification zone (ASZ), consisting of eutectic compounds; an isothermal solidification zone (ISZ), consisting of γ solid solution; and a diffusion affected zone (DAZ), consisting of Ni-Cr rich boride and Cr-Nb-Mo-rich boride compounds. With increasing bonding temperature, the amounts of eutectic compounds in ASZ first decreased and then increased. A eutectic-free joint centerline was obtained at 1080 °C. The maximum bonding shear strength reached 728.03 MPa due to the completion of isothermal solidification. Fractographic studies revealed that the boride compounds in ASZ and the intermetallic compounds in DAZ were the main causes for the failure of joints. The fracture mode of the sample bonded at 1040 °C was brittle, and the fracture path was along the ASZ. However, the fracture mode of the sample bonded at 1080 °C was ductile, and the fracture occurred along the DAZ.
Prediction of Compressive Strength of Geopolymer Concrete Using Entirely Steel Slag Aggregates: Novel Hybrid Artificial Intelligence Approaches
Authors: Dao Dong Van , Trinh Son Hoang , Ly Hai-Bang , Pham Binh Thai
Published: March 2019

Geopolymer concrete (GPC) is applied successfully in the construction of civil engineering structures. This outcome confirmed that GPC can be used as an alternative material to conventional ordinary Portland cement concrete (OPC). Recent investigations were attempted to incorporate recycled aggregates into GPC to reduce the use of natural materials such as stone and sand. However, traditional methodology used to predict compressive strength and to find out an optimum mix for GPC is yet to be formulated, especially in cases of GPC using by-products as aggregates. In this study, we propose novel hybrid artificial intelligence (AI) approaches, namely a particle swarm optimization (PSO)-based adaptive network-based fuzzy inference system (PSOANFIS) and a genetic algorithm (GA)-based adaptive network-based fuzzy inference system (GAANFIS) to predict the 28-day compressive strength of GPC containing 100% waste slag aggregates. To construct and validate these models, 21 different mixes with 210 specimens were casted and tested. Three input parameters were used to predict the tested compressive strength of GPC, i.e., the sodium solution (NaOH) concentration (varied from 10 to 14 M), the mass ratio of alkaline activation solution to fly ash (AAS/FA), ranging from 0.4 to 0.5, and the mass ratio of sodium silicate (Na2SiO3) to sodium hydroxide solution (SS/SH) which was varied from 2 to 3. The compressive strength of the fabricated GPC was used as output parameter for the prediction models. Validation of the models was done using several statistical criteria such as mean absolute error (MAE), root-mean-square error (RMSE), and correlation coefficient (R). The results show that the PSOANFIS and GAANFIS models have strong potential for predicting the 28-day compressive strength of GPC, but the PSOANFIS (MAE = 1.847 MPa, RMSE = 2.251 MPa, and R = 0.934) was slightly better than the GAANFIS (MAE = 2.115 MPa, RMSE = 2.531 MPa, and R = 0.927). This study will help in reducing the time and cost for the implementation of laboratory experiments in designing the optimum proportions of GPC.
Bandwidth-Enhanced Circularly Polarized Crescent-Shaped Slot Antenna via Circular-Patch Loading
Authors: Trinh-Van Son , Yang Youngoo , Lee Kang-Yoon , Kim Yong Serk , Hwang Keum Cheol
Published: March 2019

This paper presents the crescent-shaped slot antenna loading of a circular patch that greatly enhances a 3 dB axial-ratio (AR) bandwidth. A bent feeding line was introduced and attached to a 50- Ω microstrip feed line to achieve circular polarization operation. By loading the circular patch into a crescent-shaped slot at a proper position, the 3 dB AR bandwidth is considerably broadened. An antenna prototype with overall dimensions of 50.8 × 50.8 × 0.5 mm 3 is experimentally demonstrated. Measurement results of the fabricated antenna showed a wide −10 dB reflection bandwidth of 92.33% (1.79–4.86 GHz) and a broad 3 dB AR bandwidth of 84.40% (1.89–4.65 GHz). The measured peak gain of the antenna was approximately 4.09 dBic at 2.9 GHz. Good agreement was also achieved between measurement and simulation results.
Fresh Frozen Allogeneic Bone Block in Maxillary Sinus Floor Elevation: Histomorphometric Analysis of a Bone Specimen Retrieved 15 Years after Grafting Procedure
Authors: Stacchi Claudio , Berton Federico , Fiorillo Luca , Nicolin Vanessa , Lombardi Teresa , Cicciù Marco , Di Lenarda Roberto
Published: March 2019

Nowadays implant-prosthetic rehabilitations are one of the best solutions for rehabilitating our patients. These allow obtaining rehabilitations with optimal functional and aesthetic performances. Often patients, who undergo implant-prosthetic therapy, have the conditions of edentulias, single or multiple, that have been going on for some time. This, according to the literature, produces resorption of the alveolar bone, a process that is complicated in the posterior area of the upper arch by a pneumatization of the maxillary sinuses. The loss of vertical height, so that the implant fixtures can be inserted, requires a maneuver called maxillary sinus floor elevation. This procedure, now safely performed with piezoelectric instruments, allows increasing bone height through bone grafting. In this study, the tissue obtained from a patient, after 15 years from the intervention, was evaluated by histological and SEM analyses. The bone healing in the patient has led to a perfect integration between the patient’s bone and the fresh frozen allograft used, however still present and detectable after 15 years.
Negotiation-Free Encryption for Securing Vehicular Unicasting Communication
Authors: Mei Fang , Liu Shengjie , Wang Jian , Ge Yuming , Feng Tie
Published: March 2019

Thanks to the rapid development of vehicle-to-everything (V2X) and sensor technology, states of vehicles can be accurately measured and stored jointly in the cloud. These states can be viewed as a set of infinite attributes, such as the density around the motor vehicle, signal strength and so on. As such, the vehicle can be viewed as a moving object. The vehicle state can be measured, and its entropy is large. In vehicle networking, unicast communications between vehicles must be encrypted. The previous approach was to negotiate a session key through the Diffie-Hellman algorithm and then use the session key to encrypt the communications. This method not only needs to know in advance the peer IP of the communication, but it also needs a long time to establish a session key. Therefore, it is not suitable for vehicle networking. For the fast-changing vehicle networking, the session key establishment process should be shortened or even canceled. In this paper, we propose a method of Negotiation-free encryption for securing vehicular unicasting communications to improve the efficiency of vehicle ad hoc network transmissions.
Multi-Resonant-Based Sliding Mode Control of DFIG-Based Wind System under Unbalanced and Harmonic Network Conditions
Authors: Quan Yu , Hang Lijun , He Yuanbin , Zhang Yao
Published: March 2019

In general, the integral sliding mode control (ISMC) with an integral sliding surface would lead to tracking errors under unbalanced and harmonic grid voltage conditions. In order to eliminate tracking errors under these conditions, multi-resonant items are added to the conventional integral sliding surface in the proposed strategy, which can be called multi-resonant-based sliding mode control (MRSMC). A comparison of tracking precision on the ISMC and MRSMC is analyzed. In order to regulate the system powers directly, the errors of instantaneous active and reactive powers are selected as the state variables. Finally, the output current harmonics and a majority of the doubly-fed induction generator’s (DFIG) electromagnetic torque pulsations can be removed under unbalanced and harmonic grid voltage conditions. Simulation and experimental results are presented to verify the correctness and effectiveness of the proposed strategy.
Evaluation of Specific Absorption Rate in Three-Layered Tissue Model at 13.56 MHz and 40.68 MHz for Inductively Powered Biomedical Implants
Authors: Mohanarangam Krithikaa , Palagani Yellappa , Choi Jun Rim
Published: March 2019

This paper presents an optimized 3-coil inductive wireless power transfer (WPT) system at 13.56 MHz and 40.68 MHz to show and compare the specific absorption rate (SAR) effects on human tissue. This work also substantiates the effects of perfect alignment, lateral and/or angular misalignments on the power transfer efficiency (PTE) of the proposed WPT system. Additionally, the impacts of different tissue composition, input power and coil shape on the SAR are analyzed. The distance between the external and implantable coils is 10 mm. The results have been verified through simulations and measurements. The simulated results show that the SAR of the system at 40.68 MHz had crossed the limit designated by the Federal Communications Commission and hence, it is unsafe and causes tissue damage. Measurement results of the system in air medium show that the optimized printed circuit board coils at 13.56 MHz achieved a PTE of 41.7% whereas PTE waned to 18.2% and 15.4% at 10 mm of lateral misalignment and 60° of angular misalignment respectively. The PTE of a combination of 10 mm lateral misalignment and 60° angular misalignment is 21%. To analyze in a real-environment, a boneless pork sample with 10 mm of thickness is placed as a medium between the external and implantable coils. At perfect alignment, the PTE through pork sample is 30.8%. A RF power generator operating at 13.56 MHz provides 1 W input power to the external coil and the power delivered to load through the air and tissue mediums are 347 mW and 266 mW respectively.
The Influence of Temperature on Metabolisms of Phosphorus Accumulating Organisms in Biological Wastewater Treatment Plants in the Presence of Cu(II) Toxicity
Authors: Chou Chen-Chiang , Yang Chih-Chi , Lu Meng-Shan , Hu Li-Yuan , Chen Ku-Fan , Tsai Yung-Pin
Published: March 2019

The purpose of this study was to study how temperature variation affects the tolerance of phosphorus accumulating organisms (PAOs) in a toxic environment. To exclude the interference of glycogen accumulating organisms (GAOs), shock loading experiments were conducted to study the effect of Cu(II) toxicity on the metabolisms of PAOs in 10, 20, and 30 °C conditions. The experimental data showed that the temperature effects on aerobic phosphorus uptake, PHA degradation, and glycogen synthesis were remarkable in the presence of Cu(II). Nevertheless, insignificant effects on anaerobic phosphorus release and PHA synthesis were found. The largest inhibition of PAO metabolism occurred in the low temperature case (10 °C). This study also experimentally demonstrated the loss of PAO metabolic ability in the subsequent aerobic stage, after the anaerobic stage. The presence of Cu(II) toxicity mainly resulted from the inhibition of biochemical reactions in the aerobic stage, and it was irrelevant to the inhibition of previous anaerobic metabolisms.
Dynamic Coordinated Active–Reactive Power Optimization for Active Distribution Network with Energy Storage Systems
Authors: Wang Lingling , Wang Xu , Jiang Chuanwen , Yin Shuo , Yang Meng
Published: March 2019

This paper proposes a coordinated active–reactive power optimization model for an active distribution network with energy storage systems, where the active and reactive resources are handled simultaneously. The model aims to minimize the power losses, the operation cost, and the voltage deviation of the distribution network. In particular, the reactive power capabilities of distributed generators and energy storage systems are fully utilized to minimize power losses and improve voltage profiles. The uncertainties pertaining to the forecasted values of renewable energy sources are modelled by scenario-based stochastic programming. The second-order cone programming relaxation method is used to deal with the nonlinear power flow constraints and transform the original mixed integer nonlinear programming problem into a tractable mixed integer second-order cone programming model, thus the difficulty of problem solving is significantly reduced. The 33-bus and 69-bus distribution networks are used to demonstrate the effectiveness of the proposed approach. Simulation results show that the proposed coordinated optimization approach helps improve the economic operation for active distribution network while improving the system security significantly.
Towards the Development of a Low-Cost Irradiance Nowcasting Sky Imager
Authors: Valentín Luis , Peña-Cruz Manuel I. , Moctezuma Daniela , Peña-Martínez Cesar M. , Pineda-Arellano Carlos A. , Díaz-Ponce Arturo
Published: March 2019

Solar resource assessment is fundamental to reduce the risk in selecting the solar power-plants’ location; also for designing the appropriate solar-energy conversion technology and operating new sources of solar-power generation. Having a reliable methodology for solar irradiance forecasting allows accurately identifying variations in the plant energy production and, as a consequence, determining improvements in energy supply strategies. A new trend for solar resource assessment is based on the analysis of the sky dynamics by processing a set of images of the sky dome. In this paper, a methodology for processing the sky dome images to obtain the position of the Sun is presented; this parameter is relevant to compute the solar irradiance implemented in solar resource assessment. This methodology is based on the implementation of several techniques in order to achieve a combined, fast, and robust detection system for the Sun position regardless of the conditions of the sky, which is a complex task due to the variability of the sky dynamics. Identifying the correct position of the Sun is a critical parameter to project whether, in the presence of clouds, the occlusion of the Sun is occurring, which is essential in short-term solar resource assessment, the so-called irradiance nowcasting. The experimental results confirm that the proposed methodology performs well in the detection of the position of the Sun not only in a clear-sky day, but also in a cloudy one. The proposed methodology is also a reliable tool to cover the dynamics of the sky.
Behavior of Circular CFST Columns Subjected to Different Lateral Impact Energy
Authors: Zhang Xiaoyong , Chen Yu , Shen Xiaosheng , Zhu Yao
Published: March 2019

Forty-eight circular concrete-filled steel tube (CFST) columns subjected to lateral impact were tested to investigate the behavior of circular CFST columns under axial compressive load. Analyses of effects of concrete compressive strength, impact location and impact energy on residual ultimate axial capacity, ductility and initial stiffness are provided in this paper. It is found that lateral impact has negative effects on residual ultimate axial capacity of circular CFST columns from test results. Residual ultimate axial capacity decreases as impact energy increases and impact location comes close to the end of the specimen. It is also found that increasing concrete compressive strength can reduce the negative effects of impact location on residual ultimate axial capacity. Ductility and the initial stiffness of circular CFST columns decrease as impact energy increases. Ductility and the initial stiffness increase as impact location varies from middle-length to the end of specimens. When impact energy and impact location are constant, the ductility of the specimen with 30 MPa of concrete compressive strength is better than that of other specimens with different compressive strength. Besides, analyses of strain developments for 12 typical specimens to investigate failure modes under axial compressive load are provided in this paper. Strain developments have indicated that the steel at impact location becomes plastic faster than that at other locations. Based on the test results, a calculation formula is presented to predict the residual ultimate axial capacities of circular CFST columns subjected to lateral impact, and good agreement with experimental results has been achieved.
Identification and Analysis of Exosomes by Surface-Enhanced Raman Spectroscopy
Authors: Merdalimova Anastasiia , Chernyshev Vasiliy , Nozdriukhin Daniil , Rudakovskaya Polina , Gorin Dmitry , Yashchenok Alexey
Published: March 2019

The concept of liquid biopsy has emerged as a novel approach for cancer screening, which is based on the analysis of circulating cancer biomarkers in body fluids. Among the various circulating cancer biomarkers, including Food and Drug Administration (FDA)-approved circulating tumor cells (CTC) and circulating tumor DNA (ctDNA), exosomes have attracted tremendous attention due to their ability to diagnose cancer in its early stages with high efficiency. Recently, surface-enhanced Raman spectroscopy (SERS) has been applied for the detection of cancer exosomes due to its high sensitivity, specificity, and multiplexing capability. In this article, we review recent progress in the development of SERS-based technologies for in vitro identification of circulating cancer exosomes. The accent is made on the detection strategies and interpretation of the SERS data. The problems of detecting cancer-derived exosomes from patient samples and future perspectives of SERS-based diagnostics are also discussed.
Biochar as a Multifunctional Component of the Environment—A Review
Authors: Saletnik Bogdan , Zaguła Grzegorz , Bajcar Marcin , Tarapatskyy Maria , Bobula Gabriel , Puchalski Czesław
Published: March 2019

The growing demand for electricity, caused by dynamic economic growth, leads to a decrease in the available non-renewable energy resources constituting the foundation of global power generation. A search for alternative sources of energy that can support conventional energy technologies utilizing fossil fuels is not only of key significance for the power industry but is also important from the point of view of environmental conservation and sustainable development. Plant biomass, with its specific chemical structure and high calorific value, is a promising renewable source of energy which can be utilized in numerous conversion processes, enabling the production of solid, liquid, and gaseous fuels. Methods of thermal biomass conversion include pyrolysis, i.e., a process allowing one to obtain a multifunctional product known as biochar. The article presents a review of information related to the broad uses of carbonization products. It also discusses the legal aspects and quality standards applicable to these materials. The paper draws attention to the lack of uniform legal and quality conditions, which would allow for a much better use of biochar. The review also aims to highlight the high potential for a use of biochar in different environments. The presented text attempts to emphasize the importance of biochar as an alternative to classic products used for energy, environmental and agricultural purposes.
Design and Kinematic Control of the Cable-Driven Hyper-Redundant Manipulator for Potential Underwater Applications
Authors: Tang Jianzhong , Zhang Yougong , Huang Fanghao , Li Jianpeng , Chen Zheng , Song Wei , Zhu Shiqiang , Gu Jason
Published: March 2019

Underwater manipulators are important robotic tools in the exploration of the ocean environment. Up to now, most existing underwater manipulators are rigid and with fixed 5 or 7 degrees of freedom (DOF), which may not be very suitable for some complicated underwater scenarios (e.g., pipe networks, narrow deep cavities, etc.). The biomimetic concept of muscles and tendons is also considered as continuum manipulators, but load capacity and operation accuracy are their essential drawbacks and thus limit their practical applications. Recently, the cable-driven technique has been developed for manipulators, which can include numerous joints and hyper-redundant DOF to execute tasks with dexterity and adaptability and thus they have strong potential for these complex underwater applications. In this paper, the design of a novel cable-driven hyper-redundant manipulator (CDHRM) is introduced, which is driven by multiple cables passing through the tubular structure from the base to the end-effector, and the joint numbers can be extended and decided by the specific underwater task requirements. The kinematic analysis of the proposed CDHRM is given which includes two parts: the cable-joint kinematics and the joint-end kinematics. The geometric relationship between the cable length and the joint angles are derived via the established geometric model for the cable-joint kinematics, and the projection relationship between the joint angles and end-effector’s pose is established via the spatial coordinate transformation matrix for the joint-end kinematics. Thus, the complex mapping relationships among the cables, joints and end-effectors are clearly achieved. To implement precise control, the kinematic control scheme is developed for the CDHRM with series-parallel connections and hyper-redundancy to achieve good tracking performance. The experiment on a real CDHRM system with five joints is carried out and the results verify the accuracy of kinematics solution, and the effectiveness of the proposed control design. Particularly, three experiments are tested in the underwater environment, which verifies its good tracking performance, load carrying and grasping capacity.
Grapheme-to-Phoneme Conversion with Convolutional Neural Networks
Authors: Yolchuyeva Sevinj , Németh Géza , Gyires-Tóth Bálint
Published: March 2019

Grapheme-to-phoneme (G2P) conversion is the process of generating pronunciation for words based on their written form. It has a highly essential role for natural language processing, text-to-speech synthesis and automatic speech recognition systems. In this paper, we investigate convolutional neural networks (CNN) for G2P conversion. We propose a novel CNN-based sequence-to-sequence (seq2seq) architecture for G2P conversion. Our approach includes an end-to-end CNN G2P conversion with residual connections and, furthermore, a model that utilizes a convolutional neural network (with and without residual connections) as encoder and Bi-LSTM as a decoder. We compare our approach with state-of-the-art methods, including Encoder-Decoder LSTM and Encoder-Decoder Bi-LSTM. Training and inference times, phoneme and word error rates were evaluated on the public CMUDict dataset for US English, and the best performing convolutional neural network-based architecture was also evaluated on the NetTalk dataset. Our method approaches the accuracy of previous state-of-the-art results in terms of phoneme error rate.
Coal Seam Thickness Prediction Based on Transition Probability of Structural Elements
Authors: Qi Ailing , Kang Wenhui , Zhang Guangming , Lei Haijun
Published: March 2019

Coal seam thickness prediction is crucial in coal mine design and coal mining. In order to improve the prediction accuracy, an improved Kriging interpolation method on the basis of efficient data and Radial Basis Function (RBF-Kriging) is firstly proposed to interpolate the cutting data that is obtained in pre-mining, especially at the edge of the geological surface of coal seam by taking into account the spatial structure and the efficient spatial range, ensuring the integrity of the edge data during the movement of structural elements. Subsequently, a structural element transition probability based Gaussian process progression (STTP-GPR) method is proposed to predict the coal seam thickness from the interpolated coal seam data. The experimental results demonstrated that the proposed STTP-GPR method has superior performance in coal seam thickness prediction. The average absolute error of thickness prediction for thin coal seams is 0.025 m, which significantly improves the prediction accuracy in comparison to the existing back propagation (BP) neural networks, support vector machine, and Gaussian process regression methods.
Multiuser Transmit Precoding Design for Dimming Compatible Visible Light Communications
Authors: Li Baolong , Xue Xiaomei , Wu Qiong , Liu Yang , Wu Guilu , Li Zhengquan
Published: March 2019

In multiuser visible light communication (VLC) systems, many transmit precoding (TPC) techniques have been investigated to suppress multiuser interference. However, these conventional works restrict their modulation to the special case of zero mean, which inherently limits their application to some popular modulations associated with the non-zero mean in VLC, such as pulse position modulation (PPM). Since the modulation with non-zero mean leads to more intricate optical power constraints and design objective functions than the case of zero mean, the TPC design that can support a general modulation is still an open problem. In the paper, we conceive of a general solution of the TPC scheme combined with dimming control for multiuser VLC systems, which is capable of mitigating multiuser interference, while at the same time, achieving the desired dimming level. The proposed scheme is applicable to a wide range of modulations in VLC, such as pulse amplitude modulation (PAM), PPM, and so on. Simulation results demonstrate that the proposed scheme outperforms the traditional pseudo-inverse-based zero-forcing TPC in terms of bit error rate (BER).
Analysis of Two Dimensionality Reduction Techniques for Fast Simulation of the Spectral Radiances in the Hartley-Huggins Band
Authors: del Águila Ana , Efremenko Dmitry S. , Molina García Víctor , Xu Jian
Published: March 2019

The new generation of atmospheric composition sensors such as TROPOMI is capable of providing spectra of high spatial and spectral resolution. To process this vast amount of spectral information, fast radiative transfer models (RTMs) are required. In this regard, we analyzed the efficiency of two acceleration techniques based on the principal component analysis (PCA) for simulating the Hartley-Huggins band spectra. In the first one, the PCA is used to map the data set of optical properties of the atmosphere to a lower-dimensional subspace, in which the correction function for an approximate but fast RTM is derived. The second technique is based on the dimensionality reduction of the data set of spectral radiances. Once the empirical orthogonal functions are found, the whole spectrum can be reconstructed by performing radiative transfer computations only for a specific subset of spectral points. We considered a clear-sky atmosphere where the optical properties are defined by Rayleigh scattering and trace gas absorption. Clouds can be integrated into the model as Lambertian reflectors. High computational performance is achieved by combining both techniques without losing accuracy. We found that for the Hartley-Huggins band, the combined use of these techniques yields an accuracy better than 0.05% while the speedup factor is about 20. This innovative combination of both PCA-based techniques can be applied in future works as an efficient approach for simulating the spectral radiances in other spectral regions.
A Short Note on the Potential of Utilization of Spectral AERONET-Derived Depolarization Ratios for Aerosol Classification
Authors: Zo Il-Sung , Shin Sung-Kyun
Published: March 2019

We herein present the spectral linear particle depolarization ratios (δp) from an Aerosol Robotics NETwork (AERONET) sun/sky radiometer with respect to the aerosol type. AERONET observation sites, which are representative of each aerosol type, were selected for our study. The observation data were filtered using the Ångström exponent (Å), fine-mode fraction (FMF) and single scattering albedo (ω) to ensure that the obtained values of δp were representative of each aerosol condition. We report the spectral δp values provided in the recently released AERONET version 3 inversion product for observation of the following aerosol types: dust, polluted dust, smoke, non-absorbing, moderately-absorbing and high-absorbing pollution. The AERONET-derived δp values were generally within the range of the δp values measured from lidar observations for each aerosol type. In addition, it was found that the spectral variation of δp differed according to the aerosol type. From the obtained results, we concluded that our findings provide potential insight into the identification and classification of aerosol types using remote sensing techniques.
High-Precision Atomic Mass Measurements for Fundamental Constants
Authors: Myers Edmund
Published: March 2019

Atomic mass measurements are essential for obtaining several of the fundamental constants. The most precise atomic mass measurements, at the 10−10 level of precision or better, employ measurements of cyclotron frequencies of single ions in Penning traps. We discuss the relation of atomic masses to fundamental constants in the context of the revised SI. We then review experimental methods, and the current status of measurements of the masses of the electron, proton, neutron, deuteron, tritium, helium-3, helium-4, oxygen-16, silicon-28, rubidium-87, and cesium-133. We conclude with directions for future work.
Plant-Derived Bioactives in Oral Mucosal Lesions: A Key Emphasis to Curcumin, Lycopene, Chamomile, Aloe vera, Green Tea and Coffee Properties
Authors: Salehi Bahare , Lopez-Jornet Pia , Pons-Fuster López Eduardo , Calina Daniela , Sharifi-Rad Mehdi , Ramírez-Alarcón Karina , Forman Katherine , Fernández Marcos , Martorell Miquel , Setzer William , Martins Natália , Rodrigues Célia , Sharifi-Rad Javad
Published: March 2019

Oral mucosal lesions have many etiologies, including viral or bacterial infections, local trauma or irritation, systemic disorders, and even excessive alcohol and tobacco consumption. Folk knowledge on medicinal plants and phytochemicals in the treatment of oral mucosal lesions has gained special attention among the scientific community. Thus, this review aims to provide a brief overview on the traditional knowledge of plants in the treatment of oral mucosal lesions. This review was carried out consulting reports between 2008 and 2018 of PubMed (Medline), Web of Science, Embase, Scopus, Cochrane Database, Science Direct, and Google Scholar. The chosen keywords were plant, phytochemical, oral mucosa, leukoplakia, oral lichen planus and oral health. A special emphasis was given to certain plants (e.g., chamomile, Aloe vera, green tea, and coffea) and plant-derived bioactives (e.g., curcumin, lycopene) with anti-oral mucosal lesion activity. Finally, preclinical (in vitro and in vivo) and clinical studies examining both the safety and efficacy of medicinal plants and their derived phytochemicals were also carefully addressed.
Association of MMP9-1562C/T and MMP13-77A/G Polymorphisms with Non-Small Cell Lung Cancer in Southern Chinese Population
Authors: Li Wen , Jia Ming Xi , Wang Jian Hui , Lu Jie Li , Deng Jing , Tang Jian Xin , Liu Cun
Published: March 2019

Background: Matrix metalloproteinases (MMPs) are capable of degrading and modifying most components of the extracellular matrix (ECM) and the basal membrane (BM), and play crucial roles in cancer invasion and metastasis. MMP gene expressions were regulated primarily at the transcriptional level, which was associated with tumor spread and patient prognosis. Polymorphisms in MMPs have been reported to be associated with non-small cell lung cancer (NSCLC). The objective of this study aim to evaluate the serum levels and polymorphisms of MMP-9 and MMP-13 in non-small cell lung cancer patients compared to normal subjects and their correlation to non-small cell lung cancer histopathology findings in Southern Chinese people. Methods: This case–control study included 245 patients with NSCLC and 258 healthy controls. Genomic DNA was extracted by using DNA extraction kit, genotyping was confirmed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct DNA sequencing, and serum levels of MMP-9 and MMP-13 were measured by using a specific ELISA, Human Matrix Metalloproteinase Enzyme Immunoassay Kits. Statistical analysis was carried out using the SPSS 23.0 software package. Results: The subjects carrying the TT genotype had a decreased risk of lung cancer in MMP9-1562C/T comparing with the CC genotype (p = 0.00, OR = 0.45, 95% CI = 0.29–0.68), and the MMP13-77 AA genotype was associated with a decreased risk of NSCLC by comparing with the GG genotype (p = 0.03, OR = 0.56, 95% CI = 0.33–0.94). Moreover, the C allele of MMP9-1562C/T could increase serum level of NSCLC in compared with the A allele (OR = 1.19, 95% CI = 0.75–1.89). Similarly, the AA genotype of MMP13 might be a marker of decreased serum level of lung cancer (OR = 0.76, 95% CI = 0.51–1.14). Conclusions: The results of these analyses underline the support of the notion that the CC genotype of MMP9-1562C/T and GG genotypes of MMP13-77G/A were associated with the increased risk NSCLC, and the serum levels of MMP9 and MMP13 were consistent with the results of the SNP analysis. MMP13 and MMP9 might be function as a key oncogene in NSCLC with a Southern Chinese population. Combined detection of SNP and enzyme activity between MMP9 and MMP13 are expected to be a potential diagnostic method of non-small cell lung cancer.
Enzyme-Based Electrochemical Biosensors for Microfluidic Platforms to Detect Pharmaceutical Residues in Wastewater
Authors: Campaña Ana Lucia , Florez Sergio Leonardo , Noguera Mabel Juliana , Fuentes Olga P. , Ruiz Puentes Paola , Cruz Juan C. , Osma Johann F.
Published: March 2019

Emerging water pollutants such as pharmaceutical contaminants are suspected to induce adverse effects to human health. These molecules became worrisome due to their increasingly high concentrations in surface waters. Despite this alarming situation, available data about actual concentrations in the environment is rather scarce, as it is not commonly monitored or regulated. This is aggravated even further by the absence of portable and reliable methods for their determination in the field. A promising way to tackle these issues is the use of enzyme-based and miniaturized biosensors for their electrochemical detection. Here, we present an overview of the latest developments in amperometric microfluidic biosensors that include, modeling and multiphysics simulation, design, manufacture, testing, and operation methods. Different types of biosensors are described, highlighting those based on oxidases/peroxidases and the integration with microfluidic platforms. Finally, issues regarding the stability of the biosensors and the enzyme molecules are discussed, as well as the most relevant approaches to address these obstacles.
Continuous Monitoring of pH and Blood Gases Using Ion-Sensitive and Gas-Sensitive Field Effect Transistors Operating in the Amperometric Mode in Presence of Drift
Authors: Jamasb Shahriar
Published: March 2019

Accurate and cost-effective integrated sensor systems for continuous monitoring of pH and blood gases continue to be in high demand. The capacity of ion-selective and Gas-sensitive field effect transistors (FETs) to serve as low-power sensors for accurate continuous monitoring of pH and blood gases is evaluated in the amperometric or current mode of operation. A stand-alone current-mode topology is employed in which a constant bias is applied to the gate with the drain current serving as the measuring signal. Compared with voltage-mode operation (e.g., in the feedback mode in ion-selective FETs), current-mode topologies offer the advantages of small size and low power consumption. However, the ion-selective FET (ISFET) and the Gas-sensitive FET (GasFET) exhibit a similar drift behavior, imposing a serious limitation on the accuracy of these sensors for continuous monitoring applications irrespective of the mode of operation. Given the slow temporal variation associated with the drift characteristics in both devices, a common post-processing technique that involves monitoring the variation of the drain current over short intervals of time can potentially allow extraction of the measuring signal in presence of drift in both sensor types. Furthermore, in the amperometric mode the static sensitivity of a FET-based sensor, given by the product of the FET transconductance and the sensitivity of the device threshold voltage to the measurand concentration, can be increased by adjusting the device design parameters. Increasing the sensitivity, while of interest in its own right, also enhances the accuracy of the proposed method. Rigorous analytical validation of the method is presented for GasFET operation in the amperometric mode. Moreover, the correction algorithm is verified experimentally using a Si3N4-gate ISFET operating in the amperometric mode to monitor pH variations ranging from 3.5 to 10.
Graph-Based Construction of 3D Korean Giwa House Models
Authors: Sung Mankyu
Published: March 2019

This paper proposes a graph-based algorithm for constructing 3D Korean traditional houses automatically using a computer graphics technique. In particular, we target designing the most popular traditional house type, a giwa house, whose roof is covered with a set of Korean traditional roof tiles called giwa. In our approach, we divided the whole design processes into two different parts. At a high level, we propose a special data structure called ‘modeling graphs’. A modeling graph consists of a set of nodes and edges. A node represents a particular component of the house and an edge represents the connection between two components with all associated parameters, including an offset vector between components. Users can easily add/ delete nodes and make them connect by an edge through a few mouse clicks. Once a modeling graph is built, then it is interpreted and rendered on a component-by-component basis by traversing nodes in a procedural way. At a low level, we came up with all the required parameters for constructing the components. Among all the components, the most beautiful but complicated part is the gently curved roof structures. In order to represent the sophisticated roof style, we introduce a spline curve-based modeling technique that is able to create curvy silhouettes of three different roof styles. In this process, rather than just applying a simple texture image onto the roof, which is widely used in commercial software, we actually laid out 3D giwa tiles on the roof seamlessly, which generated more realistic looks. Through many experiments, we verified that the proposed algorithm can model and render the giwa house at a real time rate.
Preliminary Human Safety Assessment (PHSA) for the Improvement of the Behavioral Aspects of Safety Climate in the Construction Industry
Authors: Fargnoli Mario , Lombardi Mara
Published: March 2019

Occupational safety in the construction industry still represents a relevant problem at a global level. In fact, the complexity of working activities in this sector requires a comprehensive approach that goes beyond normative compliance to guarantee safer working conditions. In particular, empirical research on the factors influencing the unsafe behavior of workers needs to be augmented. Thus, the relationship between human factors and safety management issues following a bottom-up approach was investigated. In particular, an easy-to-use procedure that can be used to better address workers’ safety needs augmenting the company’s safety climate and supporting safety management issues was developed. Such an approach, based on the assessment of human reliability factors, was verified in a real case study concerning the users of concrete mixer trucks. The results showed that the majority of human failures were action and retrieval errors, underlining the importance of theoretical and practical training programs as a means to improve safety behavior. In such a context, information and communication activities also resulted beneficially to augment the company’s safety climate. The proposed approach, despite its qualitative nature, allows a clearer understanding of workers’ perceptions of hazards and their risk-taking behavior, providing practical cues to monitor and improve the behavioral aspects of safety climate. Hence, these first results can contribute to augmenting safety knowledge in the construction industry, providing a basis for further investigations on the causalities related to human performances, which are considered a key element in the prevention of accidents.