bluuebunny/crossref_metadata_2025 huggingface dataset:
Delamination Buckling and Crack Propagation Simulations in Fiber-Metal Laminates Using xFEM and Cohesive Elements
Authors: De Cicco Davide , Taheri Farid
Published: December 2018

Simulation of fracture in fiber-reinforced plastics (FRP) and hybrid composites is a challenging task. This paper investigates the potential of combining the extended finite element method (xFEM) and cohesive zone method (CZM), available through LS-DYNA commercial finite element software, for effectively modeling delamination buckling and crack propagation in fiber metal laminates (FML). The investigation includes modeling the response of the standard double cantilever beam test specimen, and delamination-buckling of a 3D-FML under axial impact loading. It is shown that the adopted approach could effectively simulate the complex state of crack propagation in such materials, which involves crack propagation within the adhesive layer along the interface, and its diversion from one interface to the other. The corroboration of the numerical predictions and actual experimental observations is also demonstrated. In addition, the limitations of these numerical methodologies are discussed.
OCT Angiography: A Technique for the Assessment of Retinal and Optic Nerve Diseases in the Pediatric Population
Authors: Guirao Navarro María Concepción , Saenz de Viteri Vazquez Manuel , Zarranz-Ventura Javier , Barrio-Barrio Jesús
Published: December 2018

Optical coherence tomography angiography (OCT-A) is a novel, rapidly evolving, non-invasive imaging technique that allows images of the retinal vasculature to be obtained in a few seconds. Blood vessels of different retinal vascular plexuses and the foveal avascular zone (FAZ) can be examined without the administration of any contrast or dye. Due to these characteristics, OCT-A could be an excellent complementary test to study retinal vascularization in children. Until now, most of the studies with OCT-A have been conducted in adults and only a few have been carried out in children. In this review, we describe the principles and advantages of OCT-A over traditional imaging methods and provide a summary of the OCT-A findings in retinopathy of prematurity and other retinal and optic disc pathologies in children. In view of the promising results from studies, the advantages of a relatively rapid and non-invasive method to assess the retinal vasculature makes OCT-A a tool of which applications in the field of pediatric ophthalmology will be expanded in the near future for patient diagnosis and follow-up in every day clinical practice.
Integrating Simulation-Based Optimization for Lean Logistics: A Case Study
Authors: González-Reséndiz Jorge , Arredondo-Soto Karina Cecilia , Realyvásquez-Vargas Arturo , Híjar-Rivera Humberto , Carrillo-Gutiérrez Teresa
Published: December 2018

The present work aims at the comprehensive application of stochastic and optimization tools with the support of Information and Communication Technologies (ICT) through a case study in a logistics process for electronic goods; simulation and Response Surface Methodology (RSM) are applied for this purpose. The problem to be evaluated is to define an optimal distribution cost for products shipped to wholesale customers located in different cities in Mexico from a manufacturing plant in Tijuana, Mexico. The factors under study are the product allocation for each distribution center, finished good inventory level and on time deliveries, which are supposed to be significant to get the objective. The methodology applied for this problem considers the design of a discrete event simulation model to represent virtually the real life of logistics process, which is considered a complex system due to different activities are interrelated to carry it out. This model is used to execute the different experiments proposed by the RSM. The results obtained from simulation model were analyzed with the RSM to define the mathematical model that allows identifying the parameters of the factors in order to optimize the process. The findings prove how the ICT facilitate the application of stochastic tools with the purpose of process optimization.
A Robust Maximum Power Point Tracking Control Method for a PEM Fuel Cell Power System
Authors: Derbeli Mohamed , Barambones Oscar , Sbita Lassaad
Published: December 2018

Taking into account the limited capability of proton exchange membrane fuel cells (PEMFCs) to produce energy, it is mandatory to provide solutions, in which an efficient power produced by PEMFCs can be attained. The maximum power point tracker (MPPT) plays a considerable role in the performance improvement of the PEMFCs. Conventional MPPT algorithms showed good performances due to their simplicity and easy implementation. However, oscillations around the maximum power point and inefficiency in the case of rapid change in operating conditions are their main drawbacks. To this end, a new MPPT scheme based on a current reference estimator is presented. The main goal of this work is to keep the PEMFCs functioning at an efficient power point. This goal is achieved using the backstepping technique, which drives the DC–DC boost converter inserted between the PEMFC and the load. The stability of the proposed algorithm is demonstrated by means of Lyapunov analysis. To verify the ability of the proposed method, an extensive simulation test is executed in a Matlab–Simulink TM environment. Compared with the well-known proportional–integral (PI) controller, results indicate that the proposed backstepping technique offers rapid and adequate converging to the operating power point.
Autocorrelation Analysis of Vibro-Acoustic Signals Measured in a Test Field for Water Leak Detection
Authors: Martini Alberto , Rivola Alessandro , Troncossi Marco
Published: December 2018

Reducing losses in water distribution networks is a worldwide challenge and all utilities are developing proper strategies for the active control of leaks. Temporary or permanent grids of units for the continuous monitoring of pipelines through vibro-acoustic measurements are probably the most commonly adopted leak detection systems. Such systems generally rely on the definition of proper thresholds to detect increments in the vibration levels associated with leaks. Since the thresholds are strongly dependent on the local boundary conditions of the monitored network, the initial setup is costly and time consuming, and the risk of undetected leaks or false alarms increases. This work aims to investigate leak detection methods based on the inherent properties of the measured signals instead of their relative amplitude. In particular, the possibility of detecting water leaks in small-diameter plastic pipes by analyzing the autocorrelation function of vibro-acoustic signals is assessed. An experimental campaign is conducted in a full-scale test facility that simulates the actual network. The measurements concerning artificially generated leaks are attained by two accelerometers and one hydrophone. The experimental results confirm the effectiveness of the proposed approach, which is therefore proven as a promising tool for leak detection.
Matching Golfers’ Movement Patterns during a Golf Swing
Authors: Mears Aimée C. , Roberts Jonathan R. , Forrester Stephanie E.
Published: December 2018

The golf swing is a multidimensional movement requiring alternative data analysis methods to interpret non-linear relationships in biomechanics data related to golf shot outcomes. The purpose of this study was to use a combined principal component analysis (PCA), fuzzy coding, and multiple correspondence analysis (MCA) data analysis approach to visualise associations within key biomechanics movement patterns and impact parameters in a group of low handicap golfers. Biomechanics data was captured and analysed for 22 golfers when hitting shots with their own driver. Relationships between biomechanics variables were firstly achieved by quantifying principal components, followed by fuzzy coding and finally MCA. Clubhead velocity and ball velocity were included as supplementary data in MCA. A total of 35.9% of inertia was explained by the first factor plane of MCA. Dimension one and two, and subsequent visualisation of MCA results, showed a separation of golfers’ biomechanics (i.e., swing techniques). The MCA plot can be used to simply and quickly identify movement patterns of a group of similar handicap golfers if supported with appropriate descriptive interpretation of the data. This technique also has the potential to highlight mismatched golfer biomechanics variables which could be contributing to weaker impact parameters.
HRLB⌃2: A Reinforcement Learning Based Framework for Believable Bots
Authors: Arzate Cruz Christian , Ramirez Uresti Jorge Adolfo
Published: December 2018

The creation of believable behaviors for Non-Player Characters (NPCs) is key to improve the players’ experience while playing a game. To achieve this objective, we need to design NPCs that appear to be controlled by a human player. In this paper, we propose a hierarchical reinforcement learning framework for believable bots (HRLB⌃2). This novel approach has been designed so it can overcome two main challenges currently faced in the creation of human-like NPCs. The first difficulty is exploring domains with high-dimensional state–action spaces, while satisfying constraints imposed by traits that characterize human-like behavior. The second problem is generating behavior diversity, by also adapting to the opponent’s playing style. We evaluated the effectiveness of our framework in the domain of the 2D fighting game named Street Fighter IV. The results of our tests demonstrate that our bot behaves in a human-like manner.
Disturbance-Rejection Control for the Hover and Transition Modes of a Negative-Buoyancy Quad Tilt-Rotor Autonomous Underwater Vehicle
Authors: Wang Tao , Wang Jianqin , Wu Chao , Zhao Min , Ge Tong
Published: December 2018

This paper proposes a Negative-buoyancy Quad Tilt-rotor Autonomous Underwater Vehicle (NQTAUV), for which an attitude-tracking controller is designed for the hover and transition modes based on a disturbance-rejection control scheme. First, the structure of NQTAUV is illustrated, a mathematical model based on the Rodrigues parameters is proposed, and the attitude-tracking error model is derived. To simplify the disturbance-observer design procedure, a disturbance observer with a single parameter was designed to estimate the disturbance torque acting on the vehicle. The controller was designed to track the target attitude, and the stability of the whole system is analyzed. Finally, the performance of the proposed method was validated by three experiments. The primary benefit of the proposed method is the simplicity of its tuning and implementation.
Theoretical Study of a 0.22 THz Backward Wave Oscillator Based on a Dual-Gridded, Carbon-Nanotube Cold Cathode
Authors: Chen Qingyun , Yuan Xuesong , Cole Matthew T. , Zhang Yu , Meng Lin , Yan Yang
Published: December 2018

The carbon nanotube (CNT) cold cathode is an attractive choice for millimeter and terahertz vacuum electronic devices owning to its unique instant switch-on and high emission current density. A novel, dual-gridded, field emission architecture based on a CNT cold cathode is proposed here. CNTs are synthesized directly on the cathode surface. The first separating grid is attached to the CNT cathode surface to shape the CNT cathode array. The second separating grid is responsible for controlled extraction of electrons from the CNT emitters. The cathode surface electric field distribution has been improved drastically compared to conventional planar devices. Furthermore, a high-compression-ratio, dual-gridded, CNT-based electron gun has been designed to further increase the current density, and a 21 kV/50 mA electron beam has been obtained with beam transparency of nearly 100%, along with a compression ratio of 39. A 0.22 THz disk-loaded waveguide backward wave oscillator (BWO) based on this electron gun architecture has been realized theoretically with output power of 32 W. The results indicate that higher output power and higher frequency terahertz BWOs can be made using advanced, nanomaterial-based cold cathodes.
Ice-Templated Porous Nanocellulose-Based Materials: Current Progress and Opportunities for Materials Engineering
Authors: Gupta Shubham , Martoïa Florian , Orgéas Laurent , Dumont Pierre J. J.
Published: December 2018

Nanocelluloses (cellulose nanocrystals, CNCs, or cellulose nanofibrils, CNFs) are the elementary reinforcing constituents of plant cell walls. Because of their pronounced slenderness and outstanding intrinsic mechanical properties, nanocelluloses constitute promising building blocks for the design of future biobased high-performance materials such as nanocomposites, dense and transparent films, continuous filaments, and aerogels and foams. The research interest in nanocellulose-based aerogels and foams is recent but growing rapidly. These materials have great potential in many engineering fields, including construction, transportation, energy, and biomedical sectors. Among the various processing routes used to obtain these materials, ice-templating is one of the most regarded, owing to its simplicity and versatility and the wide variety of porous materials that this technique can provide. The focus of this review is to discuss the current state of the art and understanding of ice-templated porous nanocellulose-based materials. We provide a review of the main forming processes that use the principle of ice-templating to produce porous nanocellulose-based materials and discuss the effect of processing conditions and suspension formulation on the resulting microstructures of the materials.
Effects of Connection Type between Surface Vessel and Submersible Propeller on Motion Performance of Wave Glider
Authors: Feng Zhanxia , Chang Zongyu , Zheng Zhongqiang , Wang Panfeng
Published: December 2018

Wave Glider is an autonomous surface vehicle that directly uses wave energy to generate forward power and has been widely used in marine survey and observation. Wave Glider is composed of surface vessel, submersible propeller and the connection structure between them. Connection types are thought to be related to the performance of Wave Glider closely. In this paper, the effects of the connection structure between the surface vessel and the submersible propeller on the motion performance of the Wave Glider are studied. Several connection types such as rigid rod, cable, multi-link chain and elastic rod are applied to connect the surface vessel and the submersible propeller. The models of connection structures are developed respectively. Among them, cable model is established with a finite number of small cylinders, which connected by spring and damping elements; multi-link chain can be seen as hinged by multiple rigid rods; elastic rod model can be looked on as several segments linked with elastic components. Considering the connection characteristics, the integrated dynamic models are established by applying multi-body dynamics software ADAMS (Automatic Dynamic Analysis of Mechanical Systems) with consideration of the hydrodynamic forces on different components of Wave Glider. The propulsion performance of the Wave Glider is calculated by using numerical method, and the simulation results showed that the difference of propulsion performance with different connection types of the Wave Glider is slightly. But serious impacts can occur on the connections of rigid rod and multi-link chain. They can lead to serious extra load on the structure of Wave Glider. From the engineering practice of Wave Glider application, the cable connection is more convenient to transport, deploy, recover and store. It is also the generous connection type for wave glider.
Enhancement of the Neuroprotective Effect of Fermented Spirulina maxima Associated with Antioxidant Activities by Ultrasonic Extraction
Authors: Choi Woon Yong , Kang Do Hyung , Heo Soo-Jin , Lee Hyeon Yong
Published: December 2018

This study is the first demonstration of the neuroprotective activity of the marine alga, Spirulina maxima, fermented by Lactobacillus plantarum HY-08, which was freshly isolated from fermented vegetables. The combined process of the fermentation with ultrasonic extraction at 40 kHz for 4 hr greatly increased the amounts of β-carotene in the extract up to 1.62 mg/g, along with a high extraction yield of 18.26%, compared to 1.03 mg/g and 12.8% from ultrasonic extraction itself, and even much higher than 0.81 mg/g and 10.6% from conventional water extraction. It was also proved that the neuroprotective activities of the extract were enhanced possibly by higher contents of β-carotene in the extract, compared to those from water extraction or ultrasonic extraction itself. This extract was found to have strong antioxidant properties, with 49.01% 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, which resulted in 90.30% neuroprotective activity. Specifically, the fermented extract markedly enhanced the brain-derived neurotrophic factor (BDNF)/p-CREB signaling pathways, which can effectively prevent memory impairment in mice caused by oxidative stress. β-Carotene also increased the expression of p-CREB and BDNF, and a mechanism of their upregulation by β-carotene is first proposed in this study. It can be concluded that the strong neuroprotective effect of the extract was markedly influenced by the antioxidant activities, due to the synergistic effects of high amounts of β-carotene and other biologically active substances in the extract that can be obtained by lactic acid fermentation, combined with ultrasonic processing.
Rock Art of Soqotra, Yemen: A Forgotten Heritage Revisited
Authors: Jansen van Rensburg Julian
Published: December 2018

This paper presents a comprehensive review of historical and current rock art research on the island of Soqotra, Yemen and places these sites within a spatial framework from which it analyses themes concerning water and the visibility and invisibility of these sites within the broader landscape. The analysis of these sites shows how water was of fundamental importance to the indigenous inhabitants over the longue durée. It also highlights how rock art has not only been able to reinforce the ethnographic and historical accounts of the indigenous inhabitants, but also strengthen our temporal knowledge of the social and cultural lives of the inhabitants of Soqotra.
Evaluation of Seasonal and Synoptic Changes in Snow Accumulation in Antarctica between Five Reanalyses Products and In Situ Observations
Authors: Liu Yihui , Li Fei , Hao Weifeng
Published: December 2018

The performance of recent reanalysis products (i.e., ERA-Interim, NCEP2, MERRA, CFSR, and JRA-55) was evaluated based on in situ observations from nine automatic weather stations and one stake network to investigate the monthly and seasonal variability of the surface mass balance in Antarctica. Synoptic precipitation simulations were also evaluated by an investigation of high precipitation events. The seasonal variations showed large fluctuations and were inconsistent at each station, probably owing to the large interannual variability of snow accumulation based on the short temporal coverage of the data. The ERA-Interim and JRA-55 datasets revealed better simulated precision, with the other three models presenting similar simulations at monthly and seasonal timescales. The JRA-55 dataset captured a greater number of synoptic high precipitation events at four of the nine stations. Such events at the other five stations were mainly captured by ERA and CFSR. The NCEP2 dataset was more weakly correlated with each station on all timescales. These results indicate that significant monthly or seasonal correlations between in situ observations and the models had little effect on the capability of the reanalyses to capture high precipitation events. The precision of the five reanalysis datasets widely fluctuated in specific regions or at specific stations at different timescales. Great caution is needed when using a single reanalysis dataset to assess the surface mass balance over all of Antarctica.
Sodium Rechargeable Batteries with Electrolytes Based on Nafion Membranes Intercalated by Mixtures of Organic Solvents
Authors: Kulova Tatiana , Skundin Alexander , Chekannikov Andrey , Novikova Svetlana , Voropaeva Daria , Yaroslavtsev Andrey
Published: December 2018

The possibilities of manufacturing batteries with Nafion 117 membranes in the Na+-form intercalated by mixtures of non-aqueous organic solvents used both as an electrolyte, separator, and binder were investigated. Electrochemical stability of various organic solvent mixtures based on N,N-dimethylacetamide, ethylene carbonate, propylene carbonate, and tetrahydrofuran were characterized. It was shown that a sodium battery based on a Nafion-Na membrane intercalated by mixture of ethylene carbonate and propylene carbonate with a Na3V1.9Fe0.1(PO4)3/C positive electrode is characterized by a discharge capacity of ≈110 mAh·g−1 (current density of 10 mA·g−1) at room temperature and shows the ability to cycle without degradation during 20 cycles. Batteries with Nafion membrane electrolytes, containing N,N-dimethylacetamide, were characterized using capacity fading during cycling, which is due to the interaction of N,N-dimethylacetamide and a negative sodium electrode.
Focal Salvage Treatment of Radiorecurrent Prostate Cancer: A Narrative Review of Current Strategies and Future Perspectives
Authors: Van Son Marieke , Peters Max , Moerland Marinus , Kerkmeijer Linda , Lagendijk Jan , Van der Voort van Zyp Jochem
Published: December 2018

Over the last decades, primary prostate cancer radiotherapy saw improving developments, such as more conformal dose administration and hypofractionated treatment regimens. Still, prostate cancer recurrences after whole-gland radiotherapy remain common, especially in patients with intermediate- to high-risk disease. The vast majority of these patients are treated palliatively with androgen deprivation therapy (ADT), which exposes them to harmful side-effects and is only effective for a limited amount of time. For patients with a localized recurrent tumor and no signs of metastatic disease, local treatment with curative intent seems more rational. However, whole-gland salvage treatments such as salvage radiotherapy or salvage prostatectomy are associated with significant toxicity and are, therefore, uncommonly performed. Treatments that are solely aimed at the recurrent tumor itself, thereby better sparing the surrounding organs at risk, potentially provide a safer salvage treatment option in terms of toxicity. To achieve such tumor-targeted treatment, imaging developments have made it possible to better exclude metastatic disease and accurately discriminate the tumor. Currently, focal salvage treatment is being performed with different modalities, including brachytherapy, cryotherapy, high-intensity focused ultrasound (HIFU), and stereotactic body radiation therapy (SBRT). Oncologic outcomes seem comparable to whole-gland salvage series, but with much lower toxicity rates. In terms of oncologic control, these results will improve further with better understanding of patient selection. Other developments, such as high-field diagnostic MRI and live adaptive MRI-guided radiotherapy, will further improve precision of the treatment.
Immobilization of Arylmalonate Decarboxylase
Authors: Markošová Kristína , Husarčíková Jana , Halásová Monika , Kourist Robert , Rosenberg Michal , Stloukal Radek , Zajoncová Ludmila , Rebroš Martin
Published: December 2018

Arylmalonate decarboxylase (AMD) is a monomeric enzyme of only 26 kDa. A recombinant AMDase from Bordetella bronchiseptica was expressed in Escherichia coli and the enzyme was immobilized using different techniques: entrapment in polyvinyl alcohol (PVA) gel (LentiKats®), covalent binding onto magnetic microparticles (MMP, PERLOZA s.r.o., Lovosice, Czech Republic) and double-immobilization (MMP-LentiKats®) using the previous two methods. The double-immobilized AMDase was stable in 8 repeated biocatalytic reactions. This combined immobilization technique has the potential to be applied to different small proteins.
Organocatalysis: A Brief Overview on Its Evolution and Applications
Authors: Oliveira Vanessa , Cardoso Mariana , Forezi Luana
Published: December 2018

The use of small organic molecules as catalysts has gained increasing importance recently. These substances, the so-called organocatalysts, present a lot of advantages, like being less toxic, less polluting, and more economically viable than the organometallic catalysts that dominate asymmetric synthesis. This work intends to briefly show some classic works and recent publications, explaining the advantages of organocatalysis and the different types of compounds used in this field, as well as their course of action.
Criticial Assessment of the Photocatalytic Reduction of Cr(VI) over Au/TiO2
Authors: Ngo Anh Binh , Nguyen Hong Lien , Hollmann Dirk
Published: December 2018

The purification of drinking water is one of the most urgent challenges in developing countries, for which the efficient removal of traces of heavy metals, e.g., Cr(IV), represents a key technology. This can be achieved via photocatalysis. In this study, we compare the performance of Au/TiO2 to bare TiO2 P25 catalysts. Furthermore, the influence of the sacrificial reagent citric acid under UV-Vis and Vis excitation was investigated and a detailed investigation of the catalysts before and after reaction was performed. During the photocatalytic reduction of Cr(IV) under acidic conditions, both leaching of Au, as well as absorption of Cr, occur, resulting in new catalyst systems obtained in situ.
Improving Fe/Al2O3 Catalysts for the Reverse Water-Gas Shift Reaction: On the Effect of Cs as Activity/Selectivity Promoter
Authors: Pastor-Pérez Laura , Shah Mihir , Le Saché Estelle , Ramirez Reina Tomas
Published: December 2018

The conversion of CO2 into CO via the Reverse Water–Gas Shift (RWGS) reaction is a suitable route for CO2 valorisation. Fe-based catalysts are highly active for this reaction, but their activity and selectivity can be substantially boosted by adding Cs as a promoter. In this work we demonstrate that Cs modifies the redox behaviour and the surface chemistry of the iron-based materials. The metallic dispersion and the amount of metallic Fe centres available for the reaction depends on Cs loading. 5 wt. % of Cs is an optimum amount of dopant to achieve a fair activity/selective balance. Nevertheless, depending on the RWGS reactor operational temperature, lower concentrations of Cs also lead to acceptable catalytic performance. Along with the excellent activity of the prepared materials this work showcases their robustness for long-term runs and the strong impact of H2/CO ratio in the overall catalytic performance.
Non-Stoichiometric Redox Active Perovskite Materials for Solar Thermochemical Fuel Production: A Review
Authors: Haeussler Anita , Abanades Stéphane , Jouannaux Julien , Julbe Anne
Published: December 2018

Due to the requirement to develop carbon-free energy, solar energy conversion into chemical energy carriers is a promising solution. Thermochemical fuel production cycles are particularly interesting because they can convert carbon dioxide or water into CO or H2 with concentrated solar energy as a high-temperature process heat source. This process further valorizes and upgrades carbon dioxide into valuable and storable fuels. Development of redox active catalysts is the key challenge for the success of thermochemical cycles for solar-driven H2O and CO2 splitting. Ultimately, the achievement of economically viable solar fuel production relies on increasing the attainable solar-to-fuel energy conversion efficiency. This necessitates the discovery of novel redox-active and thermally-stable materials able to split H2O and CO2 with both high-fuel productivities and chemical conversion rates. Perovskites have recently emerged as promising reactive materials for this application as they feature high non-stoichiometric oxygen exchange capacities and diffusion rates while maintaining their crystallographic structure during cycling over a wide range of operating conditions and reduction extents. This paper provides an overview of the best performing perovskite formulations considered in recent studies, with special focus on their non-stoichiometry extent, their ability to produce solar fuel with high yield and performance stability, and the different methods developed to study the reaction kinetics.
A Middle-Aged Enzyme Still in Its Prime: Recent Advances in the Field of Cutinases
Authors: Nikolaivits Efstratios , Kanelli Maria , Dimarogona Maria , Topakas Evangelos
Published: December 2018

Cutinases are α/β hydrolases, and their role in nature is the degradation of cutin. Such enzymes are usually produced by phytopathogenic microorganisms in order to penetrate their hosts. The first focused studies on cutinases started around 50 years ago. Since then, numerous cutinases have been isolated and characterized, aiming at the elucidation of their structure–function relations. Our deeper understanding of cutinases determines the applications by which they could be utilized; from food processing and detergents, to ester synthesis and polymerizations. However, cutinases are mainly efficient in the degradation of polyesters, a natural function. Therefore, these enzymes have been successfully applied for the biodegradation of plastics, as well as for the delicate superficial hydrolysis of polymeric materials prior to their functionalization. Even though research on this family of enzymes essentially began five decades ago, they are still involved in many reports; novel enzymes are being discovered, and new fields of applications arise, leading to numerous related publications per year. Perhaps the future of cutinases lies in their evolved descendants, such as polyesterases, and particularly PETases. The present article reviews the biochemical and structural characteristics of cutinases and cutinase-like hydrolases, and their applications in the field of bioremediation and biocatalysis.
Elemental Mercury Adsorption by Cupric Chloride-Modified Mesoporous Carbon Aerogel
Authors: Liu Dongjing , Lu Cheng , Wu Jiang
Published: December 2018

Mesoporous carbon aerogels (MCA) synthesized via aqueous polymerization of resorcinol and formaldehyde were modified by copper chloride and applied for adsorption removal of elemental mercury (Hg0) at a low temperature. The sorbents were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, and X-ray photoelectron spectroscopy (XPS) techniques. The results show that CuCl2-modified MCA exhibited good ability for Hg0 adsorption in the 40–160 °C temperature range, with Hg0 removal efficiency all above 95.0%. The Hg0 removal efficiency first increased and then decreased with the elevation of reaction temperature. It performed optimally at 80 °C with the highest Hg0 removal efficiency of 98.7%. XPS results indicate that covalent chlorines (C-Cl groups) play an important role in elemental mercury adsorption process. Hg0 is firstly captured in the form of oxidized mercury (Hg2+) and then reacts with C-Cl groups to form HgCl2.
Complex Dielectric and Impedance Spectroscopic Studies in a Multiferroic Composite of Bi2Fe4O9-BiFeO3
Authors: Alaka Panda , Govindaraj Ramanujan
Published: December 2018

Complex dielectric and impedance spectroscopic studies have been carried out in a detailed manner on the system comprising of Bi2Fe4O9-BiFeO3 composite particles dispersed in a α-Fe2O3 matrix as prepared using ball milling and controlled annealing treatments. This multiferroic composite is observed to exhibit a giant dielectric constant associated with a low tangent loss. A non-Debye type of relaxation has been deduced based on complex modulus analysis. Based on these studies, the important role played by bismuth ferrite nanoshell in the core-shell composite of Bi2Fe4O9-BiFeO3 is elucidated for the observed complex impedance spectroscopic properties of the system. Electron hopping across Fe2+/Fe3+ and oxygen vacancies are deduced to be playing an important role in conduction mechanisms based on activation energy analysis of the complex impedance spectroscopy results.
Decontamination of Dental Implant Surfaces by the Er:YAG Laser Beam: A Comparative in Vitro Study of Various Protocols
Authors: Nejem Wakim Rima , Namour Melanie , Nguyen Hoang Viet , Peremans Andre , Zeinoun Toni , Vanheusden Alain , Rompen Eric , Nammour Samir
Published: December 2018

Oral rehabilitation with dental implants has revolutionized the field of dentistry and has been proven to be an effective procedure. However, the incidence of peri-implantitis has become an emerging concern. The efficacy of the decontamination of the implant surface, by means of lasers, is still controversial. Previous studies have revealed a reduction in osteoblast adhesion to carbon-contaminated implant surfaces. This in-vitro study aimed to evaluate the decontamination of failed implants by assessing the carbon proportion, after irradiation by low-energy erbium yttrium-aluminum-garnet laser (Er:YAG) (Fotona; 2940 nm, Ljubljana, Slovenia) for a single and for multiple passages, until getting a surface, free of organic matters; to find the appropriate procedure for dental-implant surface-decontamination. Ninety implants were used. Thirty sterile implants were kept as a negative control. Thirty failed implants were irradiated by the Er:YAG laser, for a single passage, and the other thirty, for multiple passages. The parameters used in our experiments were an irradiation energy of 50 mJ, frequency of 30 Hz, and an energy density of 3.76 J/cm2. A sapphire tip, with a length of 8 mm, was used with concomitant water spray irrigation, under air 6 and water spray 4. Super short pulse mode (SSP) was of 50 μs; irradiation speed being 2 mm/s. We used energy-dispersive X-ray spectroscopy (EDX) to evaluate the carbon proportion on the surfaces of the sterile implants, the contaminated, and the lased implants, with one (LX1) and with three passages (LX3). Statistical analysis was performed by ANOVA. Results showed mean difference between the three groups (contaminated, LX1, and LX3) with p < 0.0001, as between LX1 and Group A (p < 0.0001), while the difference between LX3 and the control group was not statistically significant. The decontamination of the implant surfaces with a low-energy Er:YAG laser with three passages, appeared to be an encouraging approach.
Homeless in Scotland: An Oral Health and Psychosocial Needs Assessment
Authors: Beaton Laura , Coles Emma , Freeman Ruth
Published: December 2018

The aim of this research was to conduct an oral health and psychosocial needs assessment of a homeless population in Scotland to determine the levels of unmet need and provide recommendations for oral health improvement. A non-probability convenience sample of homeless people residing in seven Scottish Health Boards was collected. All consenting participants were asked to complete a questionnaire assessing their health and psychosocial needs, dental anxiety, and oral health-related quality of life. The participants’ oral health was examined by a trained and calibrated dentist and dental nurse. Eight hundred and fifty-three homeless people consented to take part. Participants had a mean D3cvMFT score of 16.9 (95% CI: 16.3, 17.6). Dental anxiety was high, with 20% scoring as dentally phobic. Respondents with higher dental anxiety were found to have significantly greater mean numbers of filled teeth than those with lower dental anxiety (t = −2.9, p < 0.05). Common oral health impacts were painful aching and discomfort while eating, experienced occasionally by 31% and 27% of the respondents, respectively. Fifty-eight percent of participants were found to have a depressive illness, and obvious decay experience was significantly higher among this section of participants (t = −4.3, p < 0.05). Homeless people in Scotland were found to be in need of a more accessible dental service than is currently available. An enhanced service should meet the oral health and psychosocial needs of this population to improve their oral health and quality of life.
Implementing an Oral Health Intervention for People Experiencing Homelessness in Scotland: A Participant Observation Study
Authors: Beaton Laura , Anderson Isobel , Humphris Gerry , Rodriguez Andrea , Freeman Ruth
Published: December 2018

Smile4life is an intervention aimed at improving the oral health of people experiencing homelessness in Scotland. The purpose of this research was to determine how this intervention was being translated from guidance into action. Data concerning Smile4life working practices were collected in three NHS Boards using participant observation. Fieldnotes taken during these observations were analysed using content analysis. This analysis revealed that there were working alliances between the oral health practitioner, the Third Sector staff, and the homeless service users, and that these alliances were affected by various barriers and enablers. The observation sessions also highlighted variations in working practices.
On Interpretational Questions for Quantum-Like Modeling of Social Lasing
Authors: Khrennikov Andrei , Alodjants Alexander , Trofimova Anastasiia , Tsarev Dmitry
Published: December 2018

The recent years were characterized by increasing interest to applications of the quantum formalism outside physics, e.g., in psychology, decision-making, socio-political studies. To distinguish such approach from quantum physics, it is called quantum-like. It is applied to modeling socio-political processes on the basis of the social laser model describing stimulated amplification of social actions. The main aim of this paper is establishing the socio-psychological interpretations of the quantum notions playing the basic role in lasing modeling. By using the Copenhagen interpretation and the operational approach to the quantum formalism, we analyze the notion of the social energy. Quantum formalizations of such notions as a social atom, s-atom, and an information field are presented. The operational approach based on the creation and annihilation operators is used. We also introduce the notion of the social color of information excitations representing characteristics linked to lasing coherence of the type of collimation. The Bose–Einstein statistics of excitations is coupled with the bandwagon effect, one of the basic effects of social psychology. By using the operational interpretation of the social energy, we present the thermodynamical derivation of this quantum statistics. The crucial role of information overload generated by the modern mass-media is emphasized. In physics laser’s resonator, the optical cavity, plays the crucial role in amplification. We model the functioning of social laser’s resonator by “distilling” the physical scheme from connection with optics. As the mathematical basis, we use the master equation for the density operator for the quantum information field.
Empirical Modeling of Radiowave Angular Power Distributions in Different Propagation Environments at 60 GHz for 5G
Authors: García Sánchez Manuel , Lemos Cid Edgar , Vázquez Alejos Ana
Published: December 2018

The design of 5th generation (5G) wireless systems requires the description and modeling of the radio channel where communication will take place. As 5G will employ massive multiple input–multiple output (MIMO) to cope with the high data rates, the channel models should include the description of radiowave angular power distribution (APD) around the terminals. In this paper, we present the results of a measurement campaign of these APDs in four different environments and provide their main parameters. This will facilitate the incorporation of these results into current 5G channel models. We also analyze the maximum received power improvement that could be achieved by combining the power reaching the terminal from different angles and provide the improvement values for the four scenarios. The research was conducted at 60 GHz, one of the frequency bands proposed for 5G systems.
A Novel Composite Equalizer Based on an Additional Cell for Series-Connected Lithium-Ion Cells
Authors: Lai Xin , Jiang Chun , Zheng Yuejiu , Gao Han , Huang Peng , Zhou Long
Published: December 2018

Cell inconsistency can lead to poor performance and safety hazards. Therefore, cell equalizer is essentially required to prevent the series-connected cells from overcharging, undercharging, and overdischarging. Among current equalization schemes, passive equalizer has a continuously wasting energy with low equalization efficiency, and active equalizer has high cost with complex circuit structure. In this study, a novel composite equalizer based on an additional cell with low complexity is presented. This method combines a passive equalizer and an active equalizer. Firstly, the configuration and circuit of our proposed composite equalizer are introduced, and the equalization principle is analyzed. On this basis, the control strategy and algorithm of the composite equalizer are further proposed. Finally, the composite equalizer is verified through simulation and experiment in various cases. The study results show that this method improves both the consistency level and the available capacity of the battery pack. Moreover, our proposed equalizer can overcome the shortcomings of commonly used equalizer and combining the advantages of different equalizer to maximize the equalization efficiency with a simpler equalizer structure.
Integrated Computer Vision and Type-2 Fuzzy CMAC Model for Classifying Pilling of Knitted Fabric
Authors: Lee Chin-Ling , Lin Cheng-Jian
Published: December 2018

Human visual inspection for classifying the pilling of knitted fabric not only consumes human resources but also causes occupational hazard because of long-term observation using human eyes. This reduces the efficiency of the entire operation. To overcome this, an integrated computer vision and type-2 fuzzy cerebellar model articulation controller (T2FCMAC) was devised for classifying the pilling of knitted fabric. First, the fast Fourier transform was used for image preprocessing to strengthen the characteristics of the pilling in the fabric image. The background and the pilling of knitted fabric were then segmented through binary and morphological operations. Characteristics of the pilling on the fabric were extracted by using image topography. A novel T2FCMAC based on the hybrid of group strategy and artificial bee colony (HGSABC) was proposed to evaluate the pilling grade of knitted fabric. The proposed T2FCMAC classifier embedded a type-2 fuzzy system within a traditional cerebellar model articulation controller (CMAC). The proposed HGSABC learning algorithm was used for adjusting the parameters of T2FCMAC classifiers and preventing the fall into a local optimum. A group search strategy was used to obtain balanced search capabilities and improve the performance of the artificial bee colony algorithm. The experimental results of the fixed and different illuminations indicated that the proposed method exhibited a superior average accuracy (97.3% and 94.6%, respectively) to other methods.
Optimization of the FIR Filter Structure in Finite Residue Field Algebra
Authors: Kaplun Dmitry , Butusov Denis , Ostrovskii Valerii , Veligosha Alexander , Gulvanskii Vyacheslav
Published: December 2018

This paper introduces a method for optimizing non-recursive filtering algorithms. A mathematical model of a non-recursive digital filter is proposed and a performance estimation is given. A method for optimizing the structural implementation of the modular digital filter is described. The essence of the optimization is that by using the property of the residue ring and the properties of the symmetric impulse response of the filter, it is possible to obtain a filter having almost a half the length of the impulse response compared to the traditional modular filter. A difference equation is given by calculating the output sample of modules p1 … pn in the modified modular digital filter. The performance of the modular filters was compared with the performance of positional non-recursive filters implemented on a digital signal processor. An example of the estimation of the hardware costs is shown to be required for implementing a modular digital filter with a modified structure. This paper substantiates the expediency of applying the natural redundancy of finite field algebra codes on the example of the possibility to reduce hardware costs by a factor of two. It is demonstrated that the accuracy of data processing in the modular digital filter is higher than the accuracy achieved with the implementation of filters on digital processors. The accuracy advantage of the proposed approach is shown experimentally by the construction of the frequency response of the non-recursive low-pass filters.
A Synthetic Aperture Radar (SAR)-Based Technique for Microwave Imaging and Material Characterization
Authors: Álvarez López Yuri , García Fernández María , Grau Raphael , Las-Heras Fernando
Published: December 2018

This contribution presents a simple and fast Synthetic Aperture Radar (SAR)-based technique for microwave imaging and material characterization from microwave measurements acquired in tomographic systems. SAR backpropagation is one of the simplest and fastest techniques for microwave imaging. However, in the case of heterogeneous objects and media, a priori information about the constitutive parameters (conductivity, permittivity) is needed for an accurate imaging. In some cases, a first guess of the constitutive parameters can be extracted from an uncorrected SAR image, and then the estimated parameters can be introduced in a second step to correct the SAR image. The main advantage of this methodology is that there is little or no need for a priori information about the object to be imaged. Besides, calculation time is not significantly increased with respect to conventional SAR, thus allowing real-time imaging capabilities. The methodology has been validated by means of measurements acquired in a cylindrical setup.
A Comprehensive Review of Recent Progress on GaN High Electron Mobility Transistors: Devices, Fabrication and Reliability
Authors: Zeng Fanming , An Judy Xilin , Zhou Guangnan , Li Wenmao , Wang Hui , Duan Tianli , Jiang Lingli , Yu Hongyu
Published: December 2018

GaN based high electron mobility transistors (HEMTs) have demonstrated extraordinary features in the applications of high power and high frequency devices. In this paper, we review recent progress in AlGaN/GaN HEMTs, including the following sections. First, challenges in device fabrication and optimizations will be discussed. Then, the latest progress in device fabrication technologies will be presented. Finally, some promising device structures from simulation studies will be discussed.
Non-Intrusive Tank-Filling Sensor Based on Sound Resonance
Authors: García Adrián , Toral Víctor , Márquez Álvaro , García Antonio , Castillo Encarnación , Parrilla Luis , Morales Diego P.
Published: December 2018

Different types of fill-level measurement systems exist in the market, but most of them imply some type of intrusion in the tank itself. In this paper, a reconfigurable system based on sound resonance for measuring the fill-level of a tank from the exterior is presented. A relation between sound resonance frequencies and the content of the tank has been found, especially as the tank gets closer to being full. A prototype has been created using reconfigurable technologies combined with wireless communications in order to control the system from an ad hoc application. With this prototype, the fill-level of different tanks has been measured with good resolution, especially when the tank is over half of its capacity.