bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential Role of Inorganic Confined Environments in Prebiotic Phosphorylation
Authors: Dass Avinash , Jaber Maguy , Brack André , Foucher Frédéric , Kee Terence , Georgelin Thomas , Westall Frances
Published: March 2018

A concise outlook on the potential role of confinement in phosphorylation and phosphate condensation pertaining to prebiotic chemistry is presented. Inorganic confinement is a relatively uncharted domain in studies concerning prebiotic chemistry, and even more so in terms of experimentation. However, molecular crowding within confined dimensions is central to the functioning of contemporary biology. There are numerous advantages to confined environments and an attempt to highlight this fact, within this article, has been undertaken, keeping in context the limitations of aqueous phase chemistry in phosphorylation and, to a certain extent, traditional approaches in prebiotic chemistry.
Improving Mechanical Properties of PVPPA Welded Joints of 7075 Aluminum Alloy by PWHT
Authors: Li Guowei , Chen Furong , Han Yongquan , Liang Yahong
Published: March 2018

In this study, 7075 aluminum alloy with a thickness of 10 mm was successfully welded with no obvious defects by pulsed variable polarity plasma arc (PVPPA) welding. The mechanical properties of PVPPA welded joints have been researched by post weld heat treatment (PWHT). The results indicate that the heat treatment strongly affects the mechanical properties of the welded joints. The tensile strength and the microhardness of the welded joints gradually improved with the increase of the solution temperature. With the increase of the solution time, the tensile strength, and microhardness first dramatically increased and then decreased slightly. The best tensile strength of 537.5 MPa and the microhardness of 143.7 HV were obtained after 490 °C × 80 min + 120 °C × 24 h, and the strength was nearly 91.2% of that of the parent metal, and increased about 35% compared with as-welded. The improvement of strength and microhardness was mainly due to the precipitation of η′ phase.
Recent Advances in Discotic Liquid Crystal-Assisted Nanoparticles
Authors: Gowda Ashwathanarayana , Kumar Sandeep
Published: March 2018

This article primarily summarizes recent advancement in the field of discotic liquid crystal (DLC) nanocomposites. Discotic liquid crystals are nanostructured materials, usually 2 to 6 nm size and have been recognized as organic semiconducting materials. Recently, it has been observed that the dispersion of small concentration of various functionalized zero-, one- and two-dimensional nanomaterials in the supramolecular order of mesophases of DLCs imparts negligible impact on liquid crystalline properties but enhances their thermal, supramolecular and electronic properties. Synthesis, characterization and dispersion of various nanoparticles in different discotics are presented.
Molecular Characterization of a Novel N-Acetylneuraminate Lyase from a Deep-Sea Symbiotic Mycoplasma
Authors: Wang Shao-lu , Li Yun-liang , Han Zhuang , Chen Xi , Chen Qi-jia , Wang Yong , He Li-sheng
Published: March 2018

N-acetylneuraminic acid (Neu5Ac) based novel pharmaceutical agents and diagnostic reagents are highly required in medical fields. However, N-acetylneuraminate lyase（NAL）for Neu5Ac synthesis is not applicable for industry due to its low catalytic efficiency. In this study, we biochemically characterized a deep-sea NAL enzyme (abbreviated form: MyNal) from a symbiotic Mycoplasma inhabiting the stomach of a deep-sea isopod, Bathynomus jamesi. Enzyme kinetic studies of MyNal showed that it exhibited a very low Km for both cleavage and synthesis activities compared to previously described NALs. Though it favors the cleavage process, MyNal out-competes the known NALs with respect to the efficiency of Neu5Ac synthesis and exhibits the highest kcat/Km values. High expression levels of recombinant MyNal could be achieved (9.56 mol L−1 culture) with a stable activity in a wide pH (5.0–9.0) and temperature (40–60 °C) range. All these features indicated that the deep-sea NAL has potential in the industrial production of Neu5Ac. Furthermore, we found that the amino acid 189 of MyNal (equivalent to Phe190 in Escherichia coli NAL), located in the sugar-binding domain, GX189DE, was also involved in conferring its enzymatic features. Therefore, the results of this study improved our understanding of the NALs from different environments and provided a model for protein engineering of NAL for biosynthesis of Neu5Ac.
Assessment of Blend PVDF Membranes, and the Effect of Polymer Concentration and Blend Composition
Authors: Ali Imtiaz , Bamaga Omar , Gzara Lassaad , Bassyouni M. , Abdel-Aziz M. , Soliman M. , Drioli Enrico , Albeirutty Mohammed
Published: March 2018

In this work, PVDF homopolymer was blended with PVDF-co-HFP copolymer and studied in terms of morphology, porosity, pore size, hydrophobicity, permeability, and mechanical properties. Different solvents, namely N-Methyl-2 pyrrolidone (NMP), Tetrahydrofuran (THF), and Dimethylformamide (DMF) solvents, were used to fabricate blended PVDF flat sheet membranes without the introduction of any pore forming agent, through a non-solvent induced phase separation (NIPS) technique. Furthermore, the performance of the fabricated membranes was investigated for pressure and thermal driven applications. The porosity of the membranes was slightly increased with the increase in the overall content of PVDF and by the inclusion of PVDF copolymer. Total PVDF content, copolymer content, and mixed-solvent have a positive effect on mechanical properties. The addition of copolymer increased the hydrophobicity when the total PVDF content was 20%. At 25% and with the inclusion of mixed-solvent, the hydrophobicity was adversely affected. The permeability of the membranes increased with the increase in the overall content of PVDF. Mixed-solvents significantly improved permeability.
Effect of Hot Mill Scale on Hydrogen Embrittlement of High Strength Steels for Pre-Stressed Concrete Structures
Authors: Cabrini Marina , Lorenzi Sergio , Pastore Tommaso , Pesenti Bucella Diego
Published: March 2018

The presence of a conductive layers of hot-formed oxide on the surface of bars for pre or post-compressing structures can promote localized attacks as a function of pH. The aggressive local environment in the occluded cells inside localized attacks has as consequence the possibility of initiation of stress corrosion cracking. In this paper, the stress corrosion cracking behavior of high strength steels proposed for tendons was studied by means of Constant Load (CL) tests and Slow Strain Rate (SSR) tests. Critical ranges of pH for cracking were verified. The promoting role of localized attack was confirmed. Further, electrochemical tests were performed on bars in as received surface conditions, in order to evaluate pitting initiation. The adverse effect of mill scale was recognized.
Adaptive Absolute Ego-Motion Estimation Using Wearable Visual-Inertial Sensors for Indoor Positioning
Authors: Tian Ya , Chen Zhe , Lu Shouyin , Tan Jindong
Published: March 2018

This paper proposes an adaptive absolute ego-motion estimation method using wearable visual-inertial sensors for indoor positioning. We introduce a wearable visual-inertial device to estimate not only the camera ego-motion, but also the 3D motion of the moving object in dynamic environments. Firstly, a novel method dynamic scene segmentation is proposed using two visual geometry constraints with the help of inertial sensors. Moreover, this paper introduces a concept of “virtual camera” to consider the motion area related to each moving object as if a static object were viewed by a “virtual camera”. We therefore derive the 3D moving object’s motion from the motions for the real and virtual camera because the virtual camera’s motion is actually the combined motion of both the real camera and the moving object. In addition, a multi-rate linear Kalman-filter (MR-LKF) as our previous work was selected to solve both the problem of scale ambiguity in monocular camera tracking and the different sampling frequencies of visual and inertial sensors. The performance of the proposed method is evaluated by simulation studies and practical experiments performed in both static and dynamic environments. The results show the method’s robustness and effectiveness compared with the results from a Pioneer robot as the ground truth.
Differential Transcriptional Activation of Genes Encoding Soluble Methane Monooxygenase in a Facultative Versus an Obligate Methanotroph
Authors: Smirnova Angela , Dunfield Peter
Published: March 2018

Methanotrophs are a specialized group of bacteria that can utilize methane (CH4) as a sole energy source. A key enzyme responsible for methane oxidation is methane monooxygenase (MMO), of either a soluble, cytoplasmic type (sMMO), or a particulate, membrane-bound type (pMMO). Methylocella silvestris BL2 and Methyloferula stellata AR4 are closely related methanotroph species that oxidize methane via sMMO only. However, Methyloferula stellata is an obligate methanotroph, while Methylocella silvestris is a facultative methanotroph able to grow on several multicarbon substrates in addition to methane. We constructed transcriptional fusions of the mmo promoters of Methyloferula stellata and Methylocella silvestris to a promoterless gfp in order to compare their transcriptional regulation in response to different growth substrates, in the genetic background of both organisms. The following patterns were observed: (1) The mmo promoter of the facultative methanotroph Methylocella silvestris was either transcriptionally downregulated or repressed by any growth substrate other than methane in the genetic background of Methylocella silvetris; (2) Growth on methane alone upregulated the mmo promoter of Methylocella silvetris in its native background but not in the obligate methanotroph Methyloferula stellata; (3) The mmo promoter of Methyloferula stellata was constitutive in both organisms regardless of the growth substrate, but with much lower promoter activity than the mmo promoter of Methylocella silvetris. These results support a conclusion that a different mode of transcriptional regulation of sMMO contributes to the facultative lifestyle of Methylocella silvetris compared to the obligate methanotroph Methyloferula stellata.
Biosynthesis of Schwertmannite and Goethite in a Bioreactor with Acidophilic Fe(II)-Oxidizing Betaproteobacterium Strain GJ-E10
Authors: Miyata Naoyuki , Takahashi Ayato , Fujii Tatsuo , Hashimoto Hideki , Takada Jun
Published: March 2018

Iron oxide minerals, schwertmannite and goethite, which are naturally occurring in acidic environments are attractive nanostructured materials because of the potential diverse applications. Although the biosynthesis of schwertmannite by acidophilic Fe(II)-oxidizing microorganisms has been investigated, little is known about goethite biosynthesis under acidic conditions. To examine a biological approach to the synthesis of these minerals, bioreactor experiments were conducted with a newly isolated acidophilic betaproteobacterium. The bioproducts were characterized by powder X-ray diffraction, cryogenic Mössbauer spectroscopy, and electron microscopy. The cultures growing at 25 °C and pH 3.0 or at 37 °C and pH 2.5 oxidized Fe(II) and precipitated schwertmannite rapidly. Increasing pH at each temperature resulted in the concomitant production of goethite, and 90% pure goethite was obtained at 37 °C and pH 3.5. The goethite phase was nano-sized and had relatively large specific surface area (133 m2·g−1), leading to high sorption capacity for metal oxyanions. Schwertmannite was also a good adsorbent for oxyanions, regardless of the smaller specific surface area. Our results indicate that these acidophilic microbial cultures serve as a simple rapid system for the synthesis of nanostructured goethite as well as schwertmannite.
Interaction of Freshwater Diatom with Gold Nanoparticles: Adsorption, Assimilation, and Stabilization by Cell Exometabolites
Authors: González Aridane , Pokrovsky Oleg , Ivanova Irina , Oleinikova Olga , Feurtet-Mazel Agnes , Mornet Stephane , Baudrimont Magalie
Published: March 2018

The rising concern about the potential toxicity of synthetic gold nanoparticles (AuNPs) in aquatic environments requires a rigorous estimation of physico-chemical parameters of reactions between AuNPs and major freshwater microorganisms. This study addresses the interaction of 10-nm size, positively charged AuNPs with periphytic freshwater diatoms (Eolimna minima). The adsorption experiments on viable cells were performed in 10 mM NaCl and 5 mM NaCl + 5 mM NaHCO3 solution at a variable pH (3–10), at an AuNPs concentration from 1 µg/L to 10,000 µg/L, and an exposure time from a few minutes to 55 days. Three types of experiments, adsorption as a function of time (kinetics), pH-dependent adsorption edge, and constant-pH “Langmuirian” type isotherms, were conducted. In addition, long-term interactions (days to weeks) of live diatoms (under light and in the darkness) were performed. The adsorption was maximal at a pH from 3 to 6 and sizably decreased at a pH of 6 to 10. Results of adsorption experiments were modeled using a second order kinetic model, a Linear Programming Model, Freundlich isotherm, and a ligand binding equation for one site competition. The adsorption of AuNPs(+) most likely occurred on negatively-charged surface sites of diatom cell walls such as carboxylates or phosphorylates, similar to previously studied metal cations. Under light exposure, the AuNPs were stabilized in aqueous solution in the presence of live cells, probably due to the production of exometabolites by diatoms. The adsorbed amount of AuNPs decreased after several days of reaction, suggesting some AuNPs desorption. In the darkness, the adsorption and assimilation were stronger than under light. Overall, the behavior of positively charged AuNPs at the diatom–aqueous solution interface is similar to that of metal cations, but the affinity of aqueous AuNPs to cell exometabolites is higher, which leads to the stabilization of nanoparticles in solution in the presence of diatoms and their exudates. During photosynthetic activity and the pH rising above 9 in the vicinity of diatom cells, the adsorption of AuNPs strongly decreases, which indicates a decreasing potential toxicity of AuNPs for photosynthesizing cells. The present study demonstrates the efficiency of a thermodynamic and kinetic approach for understanding gold nanoparticles interaction with aquatic freshwater peryphytic microorganisms.
Analysis of Outcomes of the Nutritional Status in Patients Qualified for Aortic Valve Replacement in Comparison to Healthy Elderly
Authors: Wernio Edyta , Jagielak Dariusz , Dardzińska Jolanta , Aleksandrowicz-Wrona Ewa , Rogowski Jan , Gruszecka Agnieszka , Małgorzewicz Sylwia
Published: March 2018

Severe aortic stenosis (AS) is associated with the reduction of muscle mass and may be associated with deterioration of nutritional status. Furthermore, malnourished cardiac patients are characterized by a higher risk of postoperative complications and mortality. The aim of this study was the evaluation and comparison of nutritional status, appetite and body composition in older people with severe aortic stenosis before aortic valve replacement and healthy elderly volunteers. One hundred and one patients, aged >65 years old with severe AS were included in the study. Nutritional status was assessed. Body composition was estimated using bioelectrical impedance analysis. Concentrations of albumin, prealbumin, triglycerides, total cholesterol and C-reactive protein were measured, and a complete blood count was done. About 40% of AS patients were at risk of malnutrition. They had decreased hand grip strength and they lost more body mass than the control group. Malnourished AS patients were older, had lower body mass indexes (BMIs) and lower aortic valve areas in comparison to well-nourished patients. Older AS patients, like their peers, show excessive body mass and, at the same time, the features of malnutrition. They have additional factors such as unintentional weight lost and decreased muscle strength which may be associated with worse outcomes.
Preliminary Study of the Potential Extracts from Selected Plants to Improve Surface Cleaning
Authors: Vong Ai , Chong Hui , Lim Vuanghao
Published: March 2018

Environment hygiene is important for preventing infection and promoting a healthier environment in which to live or work. The goal of this study was to examine the antimicrobial effects of Citrus aurantifolia (key lime) juice and aqueous extracts of Cinnamomum iners (cinnamon) bark and Citrus hystrix (kaffir lime) leaves on the kinetic growth of Pseudomonas aeruginosa and methicillin resistance Staphylococcus aureus (MRSA). Antimicrobial activity was quantitatively evaluated using spectrophotometry and viable cell counts versus bacterial growth time. The fomite surface samples that were used in the second experiment were chosen randomly from the laboratories. They were assessed both before and after intervention using a mixture of commercial disinfectant detergent and lime juice. In the kinetic growth study, the lime juice effectively eliminated P. aeruginosa and MRSA. The cinnamon bark extract was more effective at inhibiting P. aeruginosa than MRSA. The kaffir lime leaf extract demonstrated bacteriostatic activity for the first 60 min, which then weakened after 90 min for both bacteria. The lime juice extract and commercial disinfectant mixture effectively disinfected the fomites. Further studies of the use of key lime juice as a disinfectant in the hospital environment should be conducted, as C. aurantifolia exhibits antibacterial activities against endemic microbes.
Lipase-Catalyzed Synthesis, Properties Characterization, and Application of Bio-Based Dimer Acid Cyclocarbonate
Authors: He Xin , Wu Guiying , Xu Li , Yan Jinyong , Yan Yunjun
Published: March 2018

Dimer acid cyclocarbonate (DACC) is synthesized from glycerol carbonate (GC) and Sapium sebiferum oil-derived dimer acid (DA, 9-[(Z)-non-3-enyl]-10-octylnonadecanedioic acid). Meanwhile, DACC can be used for synthetic materials of bio-based non-isocyanate polyurethane (bio-NIPU). In this study, DACC was synthesized by the esterification of dimer acid and glycerol carbonate using Novozym 435 (Candida antarctica lipase B) as the biocatalyst. Via the optimizing reaction conditions, the highest yield of 76.00% and the lowest acid value of 43.82 mg KOH/g were obtained. The product was confirmed and characterized by Fourier transform-infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Then, the synthetic DACC was further used to synthesize bio-NIPU, which was examined by FTIR, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), indicating that it possesses very good physio-chemical properties and unique material quality with a potential prospect in applications.
Swelling Behaviour of Superabsorbent Polymers for Soil Amendment under Different Loads
Authors: Lejcuś Krzysztof , Śpitalniak Michał , Dąbrowska Jolanta
Published: March 2018

One of the most important among the numerous applications of superabsorbent polymers (SAPs), also known as hydrogels, is soil improvement and supporting plant vegetation in agriculture and environmental engineering. Currently, when water scarcity involves water stress, they are becoming still more commonly used for water retention in soil. As it turns out, one of the major factors influencing the superabsorbent polymers water retention capacity (WRC) is the load of soil. The study presents test results of absorbency under load (AUL) of SAPs. The object of the analysis was cross-linked copolymer of acrylamide and potassium acrylate, of a granulation of 0.50–3.15 mm. The authors analysed the water absorption capacity of the superabsorbent polymers under loads characteristic for 3 different densities of soil (1.3 g∙cm−3, 0.9 g∙cm−3, 0.5 g∙cm−3) and three different depths of application (10 cm, 20 cm, and 30 cm). Soil load and bulk densities were simulated by using weights. The experiments were conducted with a Mecmesin Multitest 2.5-xt apparatus. The obtained results demonstrate a very significant reduction in water absorption capacity by SAP under load. For a 30 cm deep layer of soil of bulk density of 1.3 g∙cm−3, after 1 h, this value amounted to 5.0 g∙g−1, and for the control sample without load, this value amounted to more than 200 g∙g−1. For the lowest load in the experiment, which was 0.49 kPa (10 cm deep layer of soil of a bulk density of 0.5 g∙cm−3), this value was 33.0 g∙g−1 after 60 min. Loads do not only limit the volume of the swelling superabsorbent polymer but they also prolong the swelling time. The soil load caused a decrease in the absorption capacity from 338.5 g∙g−1 to 19.3 g∙g−1, as well as a prolongation of the swelling time. The rate parameter (time required to reach 63% of maximum absorption capacity) increased from 63 min for the control sample to more than 300 min for the largest analysed load of 3.83 kPa. The implications of soil load on superabsorbent polymer swelling are crucial for its usage and thus for the soil system. This knowledge might be employed for the more effective usage of superabsorbent polymers in agriculture and environmental engineering, in which they are commonly used to retain water and to support plant growth.
Validation of the SARAH-E Satellite-Based Surface Solar Radiation Estimates over India
Authors: Riihelä Aku , Kallio Viivi , Devraj Sarvesh , Sharma Anu , Lindfors Anders
Published: March 2018

We evaluate the accuracy of the satellite-based surface solar radiation dataset called Surface Solar Radiation Data Set - Heliosat (SARAH-E) against in situ measurements over a variety of sites in India between 1999 and 2014. We primarily evaluate the daily means of surface solar radiation. The results indicate that SARAH-E consistently overestimates surface solar radiation, with a mean bias of 21.9 W/m2. The results are complicated by the fact that the estimation bias is stable between 1999 and 2009 with a mean of 19.6 W/m2 but increases sharply thereafter as a result of rapidly decreasing (dimming) surface measurements of solar radiation. In addition, between 1999 and 2009, both in situ measurements and SARAH-E estimates described a statistically significant (at 95% confidence interval) trend of approximately −0.6 W/m2/year, but diverged strongly afterward. We investigated the cause of decreasing solar radiation at one site (Pune) by simulating clear-sky irradiance with local measurements of water vapor and aerosols as input to a radiative transfer model. The relationship between simulated and measured irradiance appeared to change post-2009, indicating that measured changes in the clear-sky aerosol loading are not sufficient to explain the rapid dimming in measured total irradiance. Besides instrumentation biases, possible explanations in the diverging measurements and retrievals of solar radiation may be found in the aerosol climatology used for SARAH-E generation. However, at present, we have insufficient data to conclusively identify the cause of the increasing retrieval bias. Users of the datasets are advised to be aware of the increasing bias when using the post-2009 data.
Multi-Pixel Simultaneous Classification of PolSAR Image Using Convolutional Neural Networks
Authors: Wang Lei , Xu Xin , Dong Hao , Gui Rong , Pu Fangling
Published: March 2018

Convolutional neural networks (CNN) have achieved great success in the optical image processing field. Because of the excellent performance of CNN, more and more methods based on CNN are applied to polarimetric synthetic aperture radar (PolSAR) image classification. Most CNN-based PolSAR image classification methods can only classify one pixel each time. Because all the pixels of a PolSAR image are classified independently, the inherent interrelation of different land covers is ignored. We use a fixed-feature-size CNN (FFS-CNN) to classify all pixels in a patch simultaneously. The proposed method has several advantages. First, FFS-CNN can classify all the pixels in a small patch simultaneously. When classifying a whole PolSAR image, it is faster than common CNNs. Second, FFS-CNN is trained to learn the interrelation of different land covers in a patch, so it can use the interrelation of land covers to improve the classification results. The experiments of FFS-CNN are evaluated on a Chinese Gaofen-3 PolSAR image and other two real PolSAR images. Experiment results show that FFS-CNN is comparable with the state-of-the-art PolSAR image classification methods.
Forward Behavioral Modeling of a Three-Way Amplitude Modulator-Based Transmitter Using an Augmented Memory Polynomial
Authors: Chatrath Jatin , Aziz Mohsin , Helaoui Mohamed
Published: March 2018

Reconfigurable and multi-standard RF front-ends for wireless communication and sensor networks have gained importance as building blocks for the Internet of Things. Simpler and highly-efficient transmitter architectures, which can transmit better quality signals with reduced impairments, are an important step in this direction. In this regard, mixer-less transmitter architecture, namely, the three-way amplitude modulator-based transmitter, avoids the use of imperfect mixers and frequency up-converters, and their resulting distortions, leading to an improved signal quality. In this work, an augmented memory polynomial-based model for the behavioral modeling of such mixer-less transmitter architecture is proposed. Extensive simulations and measurements have been carried out in order to validate the accuracy of the proposed modeling strategy. The performance of the proposed model is evaluated using normalized mean square error (NMSE) for long-term evolution (LTE) signals. NMSE for a LTE signal of 1.4 MHz bandwidth with 100,000 samples for digital combining and analog combining are recorded as −36.41 dB and −36.9 dB, respectively. Similarly, for a 5 MHz signal the proposed models achieves −31.93 dB and −32.08 dB NMSE using digital and analog combining, respectively. For further validation of the proposed model, amplitude-to-amplitude (AM-AM), amplitude-to-phase (AM-PM), and the spectral response of the modeled and measured data are plotted, reasonably meeting the desired modeling criteria.
Deep Spatial-Temporal Joint Feature Representation for Video Object Detection
Authors: Zhao Baojun , Zhao Boya , Tang Linbo , Han Yuqi , Wang Wenzheng
Published: March 2018

With the development of deep neural networks, many object detection frameworks have shown great success in the fields of smart surveillance, self-driving cars, and facial recognition. However, the data sources are usually videos, and the object detection frameworks are mostly established on still images and only use the spatial information, which means that the feature consistency cannot be ensured because the training procedure loses temporal information. To address these problems, we propose a single, fully-convolutional neural network-based object detection framework that involves temporal information by using Siamese networks. In the training procedure, first, the prediction network combines the multiscale feature map to handle objects of various sizes. Second, we introduce a correlation loss by using the Siamese network, which provides neighboring frame features. This correlation loss represents object co-occurrences across time to aid the consistent feature generation. Since the correlation loss should use the information of the track ID and detection label, our video object detection network has been evaluated on the large-scale ImageNet VID dataset where it achieves a 69.5% mean average precision (mAP).
Design and Implementation of a New System for Large Bridge Monitoring—GeoSHM
Authors: Meng Xiaolin , Nguyen Dinh , Xie Yilin , Owen John , Psimoulis Panagiotis , Ince Sean , Chen Qusen , Ye Jun , Bhatia Paul
Published: March 2018

Structural Health Monitoring (SHM) is a relatively new branch of civil engineering that focuses on assessing the health status of infrastructure, such as long-span bridges. Using a broad range of in-situ monitoring instruments, the purpose of the SHM is to help engineers understand the behaviour of structures, ensuring their structural integrity and the safety of the public. Under the Integrated Applications Promotion (IAP) scheme of the European Space Agency (ESA), a feasibility study (FS) project that used the Global Navigation Satellite Systems (GNSS) and Earth Observation (EO) for Structural Health Monitoring of Long-span Bridges (GeoSHM) was initiated in 2013. The GeoSHM FS Project was led by University of Nottingham and the Forth Road Bridge (Scotland, UK), which is a 2.5 km long suspension bridge across the Firth of Forth connecting Edinburgh and the Northern part of Scotland, was selected as the test structure for the GeoSHM FS project. Initial results have shown the significant potential of the GNSS and EO technologies. With these successes, the FS project was further extended to the demonstration stage, which is called the GeoSHM Demo project where two other long-span bridges in China were included as test structures. Led by UbiPOS UK Ltd. (Nottingham, UK), a Nottingham Hi-tech company, this stage focuses on addressing limitations identified during the feasibility study and developing an innovative data strategy to process, store, and interpret monitoring data. This paper will present an overview of the motivation and challenges of the GeoSHM Demo Project, a description of the software and hardware architecture and a discussion of some primary results that were obtained in the last three years.
Robust Time-Difference-of-Arrival (TDOA) Localization Using Weighted Least Squares with Cone Tangent Plane Constraint
Authors: Jin Bonan , Xu Xiaosu , Zhang Tao
Published: March 2018

Finding the position of a radiative source based on time-difference-of-arrival (TDOA) measurements from spatially separated receivers has been widely applied in sonar, radar, mobile communications and sensor networks. For the nonlinear model in the process of positioning, Taylor series and other novel methods are proposed. The idea of cone constraint provides a new way of solving this problem. However, these approaches do not always perform well and are away from the Cramer-Rao-Lower-Bound (CRLB) in the situations when the source is set at the array edge, the noise in measurement is loud, or the initial position is biased. This paper presents a weighted-least-squares (WLS) algorithm with the cone tangent plane constraint for hyperbolic positioning. The method adds the range between the source and the reference sensor as a dimension. So, the space-range frame is established. Different from other cone theories, this paper sets the reference sensor as the apex and finds the optimal source estimation on the cone. WLS is used for the optimal result from the measurement plane equations, a vertical constraint and a cone constraint. The cone constraint equation is linearized by a tangent plane. This method iterates through loops and updates the tangent plane, which approximates the truth-value on the cone. The proposed algorithm was simulated and verified under various conditions of different source positions and noises. Besides, some state-of-the-art algorithms were compared in these simulations. The results show that this algorithm is accurate and robust under poor external environment.
Design Parameter Optimization of a Silicon-Based Grating Waveguide for Performance Improvement in Biochemical Sensor Application
Authors: Hong Yoo-Seung , Cho Chun-Hyung , Sung Hyuk-Kee
Published: March 2018

We performed numerical analysis and design parameter optimization of a silicon-based grating waveguide refractive index (RI) sensor. The performance of the grating waveguide RI sensor was determined by the full-width at half-maximum (FWHM) and the shift in the resonance wavelength in the transmission spectrum. The transmission extinction, a major figure-of-merit of an RI sensor that reflects both FWHM and resonance shift performance, could be significantly improved by the proper determination of three major grating waveguide parameters: duty ratio, grating period, and etching depth. We analyzed the transmission characteristics of the grating waveguide under various design parameter conditions using a finite-difference time domain method. We achieved a transmission extinction improvement of >26 dB under a given bioenvironmental target change by the proper choice of the design procedure and parameters. This design procedure and choice of appropriate parameters would enable the widespread application of silicon-based grating waveguide in high-performance RI biochemical sensor.
A New Approach for Inspection of Selected Geometric Parameters of a Railway Track Using Image-Based Point Clouds
Authors: Gabara Grzegorz , Sawicki Piotr
Published: March 2018

The paper presents the results of testing a proposed image-based point clouds measuring method for geometric parameters determination of a railway track. The study was performed based on a configuration of digital images and reference control network. A DSLR (digital Single-Lens-Reflex) Nikon D5100 camera was used to acquire six digital images of the tested section of railway tracks. The dense point clouds and the 3D mesh model were generated with the use of two software systems, RealityCapture and PhotoScan, which have implemented different matching and 3D object reconstruction techniques: Multi-View Stereo and Semi-Global Matching, respectively. The study found that both applications could generate appropriate 3D models. Final meshes of 3D models were filtered with the MeshLab software. The CloudCompare application was used to determine the track gauge and cant for defined cross-sections, and the results obtained from point clouds by dense image matching techniques were compared with results of direct geodetic measurements. The obtained RMS difference in the horizontal (gauge) and vertical (cant) plane was RMS∆ < 0.45 mm. The achieved accuracy meets the accuracy condition of measurements and inspection of the rail tracks (error m < 1 mm), specified in the Polish branch railway instruction Id-14 (D-75) and the European technical norm EN 13848-4:2011.
EMD-Based Methodology for the Identification of a High-Speed Train Running in a Gear Operating State
Authors: Bustos Alejandro , Rubio Higinio , Castejón Cristina , García-Prada Juan
Published: March 2018

An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the operating state of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation.
Islam, Politics and Secularism in Bangladesh: Contesting the Dominant Narratives
Authors: Islam Md , Islam Md
Published: March 2018

Since late 2000s, the political landscape in Bangladesh moved from democracy to an authoritarian kleptocracy, and experienced a new set of political and social narratives. This paper aims to contest some of these dominant/official narratives which have been discursively constructed and promoted by the secularist parties (including the ruling regime) and groups in Bangladesh over recent years. Examining the sociopolitical and historical facts and figures of the country, we have identified five major contested narratives related to (a) Bengali nationalism in East Pakistan, (b) foundational ideology of Bangladesh’s war of liberation, (c) state-sponsored Islamization in Bangladesh, (d) pro-liberation and anti-liberation dichotomy, and (e) war crimes trial. Drawing on a robust content analysis of the credible secondary sources substantiated by qualitative interviews, we have examined these dominant narratives and found that they are not supported by historical evidence and popular mandate, yet have been constructed largely to support and legitimize the current authoritarian regime. The paper offers both counter-narratives and some pragmatic policy recommendations to elude increasing polarization and sociopolitical instability and foster a peaceful democratic society in Bangladesh.
Public Perceptions and Willingness to Pay for Renewable Energy: A Case Study from Greece
Authors: Ntanos Stamatios , Kyriakopoulos Grigorios , Chalikias Miltiadis , Arabatzis Garyfallos , Skordoulis Michalis
Published: March 2018

The purpose of this study is to discover the factors shaping public opinion about renewable energy sources and investigate willingness to pay for expansion of renewable energy sources in the electricity mix. Data was collected through a questionnaire applied in Nikaia, an urban municipality of Greece. The respondents have a positive attitude towards renewable energy systems. Most of them have good knowledge of solar and wind energy systems and are using solar water heating, while several respondents own a solar PV system. Environmental protection is seen as the most important reason for investing in a renewable energy system. Willingness to pay for a wider penetration of RES into the electricity mix was estimated to be 26.5 euros per quarterly electricity bill. The statistical analysis revealed the existence of a relationship between RES perceived advantages and willingness to pay for renewable energy. Furthermore, by using a binary logit model, willingness to pay was found to be positively associated with education, energy subsidies, and state support.
Integration of a Communal Henhouse and Community Composter to Increase Motivation in Recycling Programs: Overview of a Three-Year Pilot Experience in Noáin (Spain)
Authors: Storino Francesco , Plana Ramón , Usanos Monika , Morales David , Aparicio-Tejo Pedro , Muro Julio , Irigoyen Ignacio
Published: March 2018

This paper presents a three-year pilot experience of a new municipal waste management system developed in Navarre, Spain that integrates composting and hens. The aim of this new system is to motivate the general public to participate more in waste prevention programs. The Composter-Henhouse (CH) is a compact facility comprised of a henhouse and three composters. This is shared by 30 families who provide the organic part of their kitchen waste to feed the hens. Hens help speed up the composting process by depositing their droppings and turning the organic residue into compost. This study assesses the CH in terms of treatment capacity, the technical adequacy of the composting process, the quality and safety of the compost obtained and some social aspects. Over three years, the CH has managed nearly 16.5 tons of organic waste and produced approximately 5600 kg of compost and more than 6000 high-quality fresh eggs. No problems or nuisances have been reported and the level of animal welfare has been very high. The follow up of the composting process (temperature, volume reduction and compost maturity) and a physicochemical and microbiological analysis of the compost have ensured the proper management of the process. The level of involvement and user satisfaction has been outstanding and the project has presented clear social benefits.
The US Shale Gas Revolution and Its Externality on Crude Oil Prices: A Counterfactual Analysis
Authors: Liu Hongxun , Li Jianglong
Published: March 2018

The expansion of shale gas production since the mid-2000s which is commonly referred to as “shale gas revolution” has had large impacts on global energy outlook. The impact is particularly substantial when it comes to the oil market because natural gas and oil are substitutes in consumption and complements and rivals in production. This paper investigates the price externality of shale gas revolution on crude oil. Applying a structural vector autoregressive model (VAR) model, the effect of natural gas production on real oil price is identified in particular, and then based on the identification, counterfactuals of oil price without shale gas revolution are constructed. We find that after the expansion of shale gas production, the real West Texas Intermediate (WTI) oil price is depressed by 10.22 USD/barrel on average from 2007 to 2017, and the magnitude seems to increase with time. In addition, the period before shale gas revolution is used as a “thought experiment” for placebo study. The results support the hypothesis that real WTI oil price can be reasonably reproduced by our models, and the estimated gap for oil price during 2007–2017 can be attributed to shale gas revolution. The methodology and framework can be applied to evaluate the economic impacts of other programs or policies.
Linking Importance–Performance Analysis, Satisfaction, and Loyalty: A Study of Savannah, GA
Authors: Deng Jinyang , Pierskalla Chad
Published: March 2018

Importance–performance analysis (IPA) has been widely used to examine the relationship between importance, performance, and overall satisfaction in tourism destinations. IPA implicitly assumes that attribute performance will have little impact on overall satisfaction when stated importance is low. However, this assumption is rarely tested. This study, for the first time, tested this assumption by including attributes in each IPA quadrant into a second-order structural equation model. Results indicate that attributes with lower ratings of importance in the “low priority” and “potential overkill” quadrants do not contribute to overall satisfaction, regardless of performance, while the opposite is true for attributes in the “keep up the good work” quadrant with higher ratings of importance and performance, thus confirming the validity of this assumption. This novel approach allowed us to take a fresh look at an old debate, and the results suggest stated importance may be more useful than previously thought. Theoretical, methodological, and managerial implications are discussed.
Potential of Ripe Plantain Fruit Peels as an Ecofriendly Catalyst for Biodiesel Synthesis: Optimization by Artificial Neural Network Integrated with Genetic Algorithm
Authors: Etim Anietie , Betiku Eriola , Ajala Sheriff , Olaniyi Peter , Ojumu Tunde
Published: March 2018

The present work was aimed at assessing the possible use of ripe plantain fruit peel as a green-base catalyst in synthesizing Azadirachta indica oil methyl esters (AIOME). The free fatty acid content of the oil (5.81 wt %) was initially reduced to 0.90 wt % using methanol: oil at 2.19 v/v, Fe2(SO4)3 at 6 wt %, time of 15 min and temperature of 65 °C. The pretreated oil was converted to AIOME in a transesterification process with calcined ripe plantain peel ash (CRPPA) at 700 °C as catalyst. The process was modeled by artificial neural network and optimized using genetic algorithm. The effectiveness of the developed CRPPA is ascribable to its high K content and microstructural transformation. The reliability of the model obtained was confirmed with a high coefficient of determination (R2) of 0.996 and a low mean relative percentage deviation (MRPD) of 8.10%. The best operating variables combination for the process was methanol:oil of 0.73 v/v, CRPPA of 0.65 wt % and time of 57 min while the temperature was kept constant at 65 °C with a corresponding AIOME yield of 99.2 wt %. The results of this work demonstrated the potentials of ripe plantain peels and neem oil as cheap feedstocks for biodiesel production.
How Can Big Data Complement Expert Analysis? A Value Chain Case Study
Authors: Kim Kyungtae , Lee Sungjoo
Published: March 2018

In the world of big data, there is a need to investigate how data-driven approaches can support expert-based analyses during a technology planning process. To meet this goal, we examined opportunities and challenges for big data analytics in the social sciences, particularly with respect to value chain analysis. To accomplish this, we designed a value chain mapping experiment that aimed to compare the results of expert-based and data-based mappings. In the expert-based approach, we asked an industry expert to visually depict an industry value chain based on insights and collected data. We also reviewed a previously published value chain developed by a panel of industry experts during a national technology planning process. In the data-driven analysis, we used a massive number of business transaction records between companies under the assumption that the data would be useful in identifying relationships between items in a value chain. The case study results demonstrated that data-driven analysis can help researchers understand the current status of industry structures, enabling them to develop more realistic, although less flexible value chain maps. This approach is expected to provide more value when used in combination with other databases. It is important to note that significant effort is required to develop an elaborate analysis algorithm, and data preprocessing is essential for obtaining meaningful results, both of which make this approach challenging. Experts’ insights are still helpful for validating the analytic results in value chain mapping.
Environmental Practices. Motivations and Their Influence on the Level of Implementation
Authors: Del Río-Rama María , Álvarez-García José , Oliveira Cristiana
Published: March 2018

The objective of this research is to identify and analyze good environmental practices followed by the Thermal sector in Spain. It is also to analyze if the motivations that lead thermal establishments to implement environmental practices influence their level of implementation. The methodology used is the performance of a descriptive and regression analysis of the data obtained through a structured questionnaire. The target population consists of 112 health resorts, obtaining a sample size of 62 valid surveys, which implies a response rate of 55.36%. The results obtained have enabled the performance of an environmental diagnosis of the Thermal sector in Spain, identifying the strengths and weaknesses of Environmental Management, as well as corroborating that motivations affect the level of implementation of environmental practices.
Quantifying Impacts of Land-Use/Cover Change on Urban Vegetation Gross Primary Production: A Case Study of Wuhan, China
Authors: Liu Shishi , Du Wei , Su Hang , Wang Shanqin , Guan Qingfeng
Published: March 2018

This study quantified the impacts of land-use/cover change (LUCC) on gross primary production (GPP) during 2000–2013 in a typical densely urbanized Chinese city, Wuhan. GPP was estimated at 30-m spatial resolution using annual land cover maps, meteorological data of the baseline year, and the normalized difference vegetation index (NDVI), which was generated with the spatial and temporal adaptive reflectance fusion model (STARFM) based on Landsat and MODIS images. The results showed that approximately 309.95 Gg C was lost over 13 years, which was mainly due to the conversion from cropland to built-up areas. The interannual variation of GPP was affected by the change of vegetation composition, especially the increasing relative fraction of forests. The loss of GPP due to the conversion from forest to cropland fluctuated through the study period, but showed a sharp decrease in 2007 and 2008. The gain of GPP due to the conversion from cropland to forest was low between 2001 and 2009, but increased dramatically between 2009 and 2013. The change rate map showed an increasing trend along the highways, and a decreasing trend around the metropolitan area and lakes. The results indicated that carbon consequences should be considered before land management policies are put forth.