bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematic Physical Exercise and Spirulina maxima Supplementation Improve Body Composition, Cardiorespiratory Fitness, and Blood Lipid Profile: Correlations of a Randomized Double-Blind Controlled Trial
Authors: Hernández-Lepe Marco Antonio , Olivas-Aguirre Francisco Javier , Gómez-Miranda Luis Mario , Hernández-Torres Rosa Patricia , Manríquez-Torres José de Jesús , Ramos-Jiménez Arnulfo
Published: October 2019

Cardiovascular diseases are part of the highly preventable chronic diseases associated with changes in lifestyle. Within them, physical activity, low-fat and high-fiber diets are distinguished as the main support for prevention, even when supplementation with nutraceuticals has become a very common practice. Fifty-two young sedentary men with excess body weight (body mass index (BMI) ≥ 25 kg·m−2) were enrolled in a randomized-crossover controlled trial [six weeks of a systematic physical exercise with Spirulina maxima or placebo supplementation (4.5 g·day−1)]. Body composition, blood lipid profile, and maximal oxygen uptake were determined pre/post intervention. Pairwise comparisons showed a significant improvement (p < 0.01) on blood lipid profile in the group of exercise plus Spirulina maxima. Moreover, correlations of absolute changes of BMI, body fat percentage, blood lipids and maximal oxygen uptake were statistically significant (p < 0.01). These results indicate that the Spirulina maxima supplementation could be acting in a synergistic way with exercise due to the enhanced effects on body composition, cardiorespiratory fitness, and blood lipid profile. This phenomenon should be considered to reduce risk of cardiovascular disorders. Trial registration: Clinical Trials, NCT02837666 (July 19, 2016).
Incorporating Virtual Reality into the Teaching and Training of Grid-Tie Photovoltaic Power Plants Design
Authors: Gonzalez Lopez Juan Miguel , Jimenez Betancourt Ramon Octavio , Ramirez Arredondo Juan M , Villalvazo Laureano Efrain , Rodriguez Haro Fernando
Published: October 2019

The current difficulty in obtaining financial resources to acquire equipment for training personnel and the requirement of well-trained engineers in the industry looking toward sustainability, creates an opportunity to innovate in teaching tools, such as the proposed in this article, where a virtual world is projected, integrating the planning and design of a photovoltaic power plant (PV). The user can interact while immersed in the virtual scene as if the PV system were already installed, illustrating technical characteristics of selected equipment and its installation details, while the user is interacting with didactic activities focused on visual, auditory, and kinesthetic learning. This paper summarizes an initiative within the teaching–learning context, which aims to show the advantages of using modern tools, such as virtual reality, to achieve teaching goals in a renewable energy course.
Carbon Mineralization in a Soil Amended with Sewage Sludge-Derived Biochar
Authors: Figueiredo Cícero Célio de , Coser Thais Rodrigues , Moreira Túlio Nascimento , Leão Tairone Paiva , Vale Ailton Teixeira do , Paz-Ferreiro Jorge
Published: October 2019

Biochar has been presented as a multifunctional material with short- and long-term agro-environmental benefits, including soil organic matter stabilization, improved nutrient cycling, and increased primary productivity. However, its turnover time, when applied to soil, varies greatly depending on feedstock and pyrolysis temperature. For sewage sludge-derived biochars, which have high N contents, there is still a major uncertainty regarding the influence of pyrolysis temperatures on soil carbon mineralization and its relationship to soil N availability. Sewage sludge and sewage sludge-derived biochars produced at 300 °C (BC300), 400 °C (BC400), and 500 °C (BC500) were added to an Oxisol in a short-term incubation experiment. Carbon mineralization and nitrogen availability (N-NH4+ and N-NO3−) were studied using a first-order model. BC300 and BC400 showed higher soil C mineralization rates and N-NH4+ contents, demonstrating their potential to be used for plant nutrition. Compared to the control, the cumulative C-CO2 emissions increased by 60–64% when biochars BC300 and BC400 were applied to soil. On the other hand, C-CO2 emissions decreased by 6% after the addition of BC500, indicating the predominance of recalcitrant compounds, which results in a lower supply of soil N-NH4+ (83.4 mg kg−1) in BC500, being 67% lower than BC300 (255.7 mg kg−1). Soil N availability was strongly influenced by total N, total C, C/N ratio, H, pore volume, and specific surface area in the biochars.
Study on the Dynamic Characteristics of a Hydraulic Continuous Variable Compression Ratio System
Authors: Chen Jiadui , Wang Bo , Liu Dan , Yang Kai
Published: October 2019

Variable compression ratio (VCR) technology has long been recognized as a method for improving the engine performance, efficiency, and fuel economy of automobiles, with reduced emissions. In this paper, a novel hydraulic continuous VCR system based on the principle of an adjustable hydraulic volume is introduced. The continuous variable compression ratio of the VCR system is realized by the hydraulic system controlling the rotation of the eccentric pin to change the positions of the top dead center (TDC) and the bottom dead center (BDC). The construction of the mathematical model and simulation model of the VCR system is also presented in this paper. The piston motion characteristics, flow characteristics, and pressure characteristics of the hydraulic system of the VCR system at different engine speeds and adjustment quantities are studied by simulation in this paper. The simulation results show that the VCR system has a fast response and good dynamic characteristics, and can achieve continuous adjustment of the compression ratio.
Green Production of Glycerol Ketals with a Clay-Based Heterogeneous Acid Catalyst
Authors: Amri Sondes , Gómez Jaime , Balea Ana , Merayo Noemi , Srasra Ezzeddine , Besbes Néji , Ladero Miguel
Published: October 2019

Glycerol remains a bottleneck for the biodiesel industry as well as an opportunity from the biorefinery perspective, having a notable reactivity as a platform chemical. In particular, glycerol ketals can be envisaged as oxygenates for fuel formulation. In this study, we have focused on the green synthesis of glycerol ketals by reacting glycerol with acyclic (acetone, butanone) and cyclic (cyclohexanone) ketones in the presence of an acid activated clay Tunisian AC in homogeneous systems under quasi-solventless conditions. These reactions were followed by on-line Fourier Transform Infrared Spectroscopy (FTIR) (namely, ReactIR 10). Firstly, the contacting time was selected studying the activity, stability and chemical characteristics of a set of catalysts. The 1-h activated clay AC was further characterized by X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electronic Microscopy with Energy Dispersive Spectroscopy (SEM/EDS). Finally, the effect of the main operational variables (catalyst concentration, reagents molar ratio, time and temperature) were checked and we reflected on adequate second-order kinetic models with partial first-order deactivation.
Frequency and Intensity of Electrical Stimulation of Human Sympathetic Ganglia Affect Heart Rate Variability and Pain Threshold
Authors: Cho Sung-Hyoun
Published: October 2019

The study relates to the selection of effective clinical treatments based on the changes associated with each electrical stimulation condition. The aim was to investigate the effects of electrical stimulation on the autonomic nervous system by evaluating the heart rate variability (HRV) and pain threshold in response to different interferential current conditions applied to the sympathetic ganglia. Forty five participants were randomly assigned to receive high frequency-low intensity (HF-LI), low frequency-high intensity (LF-HI), or high frequency-high intensity (HF-HI) electrical stimulation. We then used bipolar adhesive pad electrodes to stimulate the thoracic vertebrae T1–T4 for 20 min, and changes were evaluated before, immediately after and 30 min after electrical stimulation. Results revealed significant HRV immediately after HF-LI and LF-HI electrical stimulations. This present study finding of a reduction in HRV immediately after HF-HI electrical stimulation confirms HRV measurement reliability based on electrical stimulation parameters. Results revealed a significant increase in the pain threshold with HF-HI electrical stimulation than for the other conditions; there was also a shorter pain duration. The present study also showed a significant effect of the HF-LI and LF-HI conditions on the pain threshold immediately after electrical stimulation, but the results after 30 min only revealed significant changes in the LF-HI group, indicating a maintenance of the pain control period immediately and 30 min after electrical stimulation. Different conditions of electrical stimulation resulted in distinct changes in HRV and pain control duration.
Application of Artificial Neural Networks in Hybrid Simulation
Authors: Mucha Waldemar
Published: October 2019

Hybrid simulation is a technique for testing mechanical systems. It applies to structures with elements hard or impossible to model numerically. These elements are tested experimentally by straining them by means of actuators, while the rest of the system is simulated numerically using a finite element method (FEM). Data is interchanged between experiment and simulation. The simulation is performed in real-time in order to accurately recreate the dynamic behavior in the experiment. FEM is very computationally demanding, and for systems with a great number of degrees of freedom (DOFs), real-time simulation with small-time steps (ensuring high accuracy) may require powerful computing hardware or may even be impossible. The author proposed to swap the finite element (FE) model with an artificial neural network (ANN) to significantly lower the computational cost of the real-time algorithm. The presented examples proved that the computational cost could be reduced by at least one number of magnitude while maintaining high accuracy of the simulation; however, obtaining appropriate ANN was not trivial and might require many attempts.
Experimental and Numerical Investigation on Repairing Effect of Polymer Grouting for Settlement of High-Speed Railway Unballasted Track
Authors: Fang Hongyuan , Su Yingjie , Du Xueming , Wang Fuming , Li Bin
Published: October 2019

Uneven settlement of high-speed railway subgrade leads to the irregularity of high-speed railway line, which seriously affects high-speed train operation. The skylight point of high-speed railway operation is short and the maintenance time is limited. Therefore, how to quickly lift and repair the ballastless track slab in the subsidence section is an urgent problem to be solved in the maintenance of high-speed railways. The two-component non-aqueous reactive polymer material has the advantages of strong expansive force, fast reaction speed, and wide application range, which is extremely suitable for the repair of high-speed railway track slab subsidence and lifting. In this study, the expansion force characteristics of different density polymer materials and the stress-deformation curves at corresponding density are tested in laboratory to propose the mechanical parameters of polymer. Then, a three-dimensional finite element (FE) model of high-speed railway train ballastless-track subgrade is established based on ABAQUS. The mechanical characteristics of CRTS III ballastless track under different repair materials, different elevation, and different density of polymer grouting materials are analyzed. The results show that, under the dynamic load of the train, the stress value of polymer repairing material is less than that of cement slurry, presenting a compressive stress state, which is similar to that of the complete subgrade surface. In addition, within a certain thickness range, increasing the thickness of polymer is beneficial to reducing the difference of stress variation between polymer filling layer and complete pavement. Once beyond this range, the thickness of polymer has little effect on the force variation.
A High-Accuracy Model Average Ensemble of Convolutional Neural Networks for Classification of Cloud Image Patches on Small Datasets
Authors: Phung Van Hiep , Rhee Eun Joo
Published: October 2019

Research on clouds has an enormous influence on sky sciences and related applications, and cloud classification plays an essential role in it. Much research has been conducted which includes both traditional machine learning approaches and deep learning approaches. Compared with traditional machine learning approaches, deep learning approaches achieved better results. However, most deep learning models need large data to train due to the large number of parameters. Therefore, they cannot get high accuracy in case of small datasets. In this paper, we propose a complete solution for high accuracy of classification of cloud image patches on small datasets. Firstly, we designed a suitable convolutional neural network (CNN) model for small datasets. Secondly, we applied regularization techniques to increase generalization and avoid overfitting of the model. Finally, we introduce a model average ensemble to reduce the variance of prediction and increase the classification accuracy. We experiment the proposed solution on the Singapore whole-sky imaging categories (SWIMCAT) dataset, which demonstrates perfect classification accuracy for most classes and confirms the robustness of the proposed model.
Development of Scalable On-Line Anomaly Detection System for Autonomous and Adaptive Manufacturing Processes
Authors: Choi Seunghyun , Youm Sekyoung , Kang Yong-Shin
Published: October 2019

Factories of the future are foreseen to evolve into smart factories with autonomous and adaptive manufacturing processes. However, the increasing complexity of the network of manufacturing processes is expected to complicate the rapid detection of process anomalies in real time. This paper proposes an architecture framework and method for the implementation of the Scalable On-line Anomaly Detection System (SOADS), which can detect process anomalies via real-time processing and analyze large amounts of process execution data in the context of autonomous and adaptive manufacturing processes. The design of this system architecture framework entailed the derivation of standard subsequence patterns using the PrefixSpan algorithm, a sequential pattern algorithm. The anomalies of the real-time event streams and derived subsequence patterns were scored using the Smith-Waterman algorithm, a sequence alignment algorithm. The excellence of the proposed system was verified by measuring the time for deriving subsequence patterns and by obtaining the anomaly scoring time from large event logs. The proposed system succeeded in large-scale data processing and analysis, one of the requirements for a smart factory, by using Apache Spark streaming and Apache Hbase, and is expected to become the basis of anomaly detection systems of smart factories.
In Vitro and In Vivo Testing of Zinc as a Biodegradable Material for Stents Fabricated by Photo-Chemical Etching
Authors: Kandala Bala Subramanya Pavan Kumar , Zhang Guangqi , Hopkins Tracy M. , An Xiaoxian , Pixley Sarah K. , Shanov Vesselin
Published: October 2019

There is an increasing interest in biodegradable metal implants made from magnesium (Mg), iron (Fe), zinc (Zn) and their alloys because they are well tolerated in vivo and have mechanical properties that approach those of non-degradable metals. In particular, Zn and its alloys show the potential to be the next generation of biodegradable materials for medical implants. However, Zn has not been as well-studied as Mg, especially for stent applications. Manufacturing stents by laser cutting has become an industry standard. Nevertheless, the use of this approach with Zn faces some challenges, such as generating thermal stress, dross sticking on the device, surface oxidation, and the need for expensive thin-walled Zn tubing and post-treatment. All of these challenges motivated us to employ photo-chemical etching for fabricating different designs of Zn (99.95% pure) stents. The stents were constructed with different strut patterns, made by photo-chemical etching, and mechanically tested to evaluate radial forces. Stents with rhombus design patterns showed a promising 0.167N/mm radial force, which was comparable to Mg-based stents. In vitro studies were conducted with uncoated Zn stents as control and Parylene C-coated Zn stents to determine corrosion rates. The Parylene C coating reduced the corrosion rate by 50% compared to uncoated stents. In vivo studies were carried out by implanting photo-chemically etched, uncoated Zn stent segments subcutaneously in a C57BL/6 mice model. Histological analyses provided favorable data about the surrounding tissue status, as well as nerve and blood vessel responses near the implant, providing insights into the in vivo degradation of the metal struts. All of these experiments confirmed that Zn has the potential for use in biodegradable stent applications.
New Hybrid Algorithms for Prediction of Daily Load of Power Network
Authors: Hu Pei , Pan Jeng-Shyang , Chu Shu-Chuan , Chai Qing-Wei , Liu Tao , Li Zhong-Cui
Published: October 2019

Two new hybrid algorithms are proposed to improve the performances of the meta-heuristic optimization algorithms, namely the Grey Wolf Optimizer (GWO) and Shuffled Frog Leaping Algorithm (SFLA). Firstly, it advances the hierarchy and position updating of the mathematical model of GWO, and then the SGWO algorithm is proposed based on the advantages of SFLA and GWO. It not only improves the ability of local search, but also speeds up the global convergence. Secondly, the SGWOD algorithm based on SGWO is proposed by using the benefit of differential evolution strategy. Through the experiments of the 29 benchmark functions, which are composed of the functions of unimodal, multimodal, fixed-dimension and composite multimodal, the performances of the new algorithms are better than that of GWO, SFLA and GWO-DE, and they greatly balances the exploration and exploitation. The proposed SGWO and SGWOD algorithms are also applied to the prediction model based on the neural network. Experimental results show the usefulness for forecasting the power daily load.
A Route Planner Using a Delegate Multi-Agent System for a Modular Manufacturing Line: Proof of Concept
Authors: Ďurica Lukáš , Gregor Michal , Vavrík Vladimír , Marschall Martin , Grznár Patrik , Mozol Štefan
Published: October 2019

Route planning in a multi-agent system (MAS) is still a complex task, especially if there is need for a continuous, decentralized planner of the routes for physical agents in a dynamic environment. It is a planner of this kind that is required in the application the article considers: the transportation of parts at a modular manufacturing line. Such a planner has to meet several difficult requirements, regarding the physical, time-constrained dynamic environment, live-locks and deadlocks, delayed agents, and last needs to minimize the travel time and the total distance traveled. The article proposes an approach using a delegate multi-agent system (D-MAS) in order to meet these requirements. The approach was verified using virtual reality so as to provide a better understanding of the planner’s issues. Several coordination rules were proposed and implemented. As a further verification, the proof-of-concept solution was compared to a non-reservation planner. It was shown, that as the number of agents increases, the approach, including the reservations, outperformed its competitor. Various recommendations for the implementation of the planner were formulated. It was concluded that the performance of the planner is sufficient for its future use. The main objective of article was proof-of-concept and determining the functionality of a prototype based on MAS that was in compliance with a modular manufacturing line developed by us.
An Innovative Green Process for the Stabilization and Valorization of the Organic Fraction of Municipal Solid Waste
Authors: Esposito Corcione Carola , Ferrari Francesca , Striani Raffaella , Minosi Stefania , Pollini Mauro , Paladini Federica , Panico Angelica , De Fazio Roberto , Visconti Paolo , Greco Antonio
Published: October 2019

This work is aimed at the development of innovative, easy and cheap methods for the stabilization, inertization and valorisation of the organic fraction of municipal solid waste (OFMSW). For the first time, two original processes for transforming the organic waste into an inert, odorless and sanitized material were here proposed. The first one, called dual step, starts with grinding of the OFMSW, by means of an industrial shredder. After being finely ground, the organic waste was exposed to a sterilization process by means of UV/ozone radiations or thermal treatment (stabilization phase) in order to obtain a complete removal of the OFMSW’s bacterial activity. By means of several microbiological analyses, the best sterilization method was chosen. The incorporation in a thermosetting matrix was, then, carried out through mixing the sterilized and finely ground organic waste into a water soluble urea formaldehyde (UF) based resin, with a formaldehyde content less than 1% wt, followed by a thermal treatment for UF-resin crosslinking (inertization phase). An alternative cheaper and easier process, called one step, was also proposed and investigated, by combining the sterilization with the curing thermal process (at higher temperature) of the thermosetting matrix. The preliminary experimental results reported in this paper suggest that both the proposed methods could be considered suitable for the production of high valorized innovative OFMSW-derived panels or bricks that could find application in several fields, such as building or construction materials. Finally, a brief description of the prototype machinery, properly designed for implementing OFMSW stabilization and valorization processes, is reported.
The New Empirical Equation Describing Damping Phenomenon in Dynamically Loaded Subgrade Cohesive Soils
Authors: Soból Emil , Głuchowski Andrzej , Szymański Alojzy , Sas Wojciech
Published: October 2019

The damping ratio (D) is one of the key soil parameters in geotechnical issues where the soil is subjected to dynamic loads, like machines foundation, city tram and subway traffic, and driving of sheet pile or precast pile. Each of the abovementioned geotechnical problems is connected with significant damping, so its effect should be included in the dynamical analysis. Therefore, this article focuses on the damping phenomenon in cohesive soils from the capital of Poland, which is described by damping ratio (D). In this research, a set of the damping tests by free vibration method in resonant column device were conducted, and the influence of four selected factors, i.e., shear strain (γ), effective stress (p’), plasticity index (PI), and void ratio (e) on damping ratio in wide strain range was investigated and discussed. Based on the laboratory tests, the shear strain has the most impacts on the damping ratio characteristics; the plasticity index and the effective stress also have a significant influence. Based on the performed analysis, the authors propose the empirical equations with two sets of variables, the first for low and medium cohesive soil (PI < 20%) and the second for very cohesive soils (PI > 20%).
Performance Enhancement and Capacity Enlargement for a DWDM-PON System Utilizing an Optimized Cross Seeding Rayleigh Backscattering Design
Authors: A. Mohammed Nazmi , Hamdi Mansi Ahmed
Published: October 2019

In this work, a record of 16 channels, with future channel spacing in the telecommunication standardization sector of the International Telecommunications Union G.694.1 (ITU-T G.694.1) for Dense Wavelength Division Multiplexing (DWDM) (i.e., 12.5 GHz), is simulated and tested. This work is done to realize a proposed high capacity DWDM-Passive Optical Network (DWDM-PON) system. These specifications are associated with enhancing the upstream (US) capacity to 2.5 Gb/s over a 25 km Single-Mode Fiber (SMF) transmission and producing a noteworthy average Bit Error Rate (BER) of 10−12 during the system’s evaluation process. These performance indicators are achieved through design optimization of the cross-seeding Rayleigh Backscattering (RB) elimination technique. This optimization has successfully reduced (compared to the cross-seeding related literature) the simulated DWDM-PON components and maintained an effective Rayleigh Backscattering elimination with the aforementioned system’s performance enhancement and capacity enlargement.
An Improved Method for Predicting the Greenfield Stratum Movements Caused by Shield Tunnel Construction
Authors: Tan XinRong , Zhang Heng , Zhang Gang , Zhu Yimo , Tu Peng
Published: October 2019

Shield tunneling is becoming the preferred construction scheme for metro construction because of its advantages of fast construction speed and small disturbance. However, limited by process defects, the stratum movements induced by the construction of shield tunnels still affects the safety of nearby underground structures and aboveground buildings. Therefore, the reliable prediction of stratum movements is important. Described in this paper is an analysis method of the Greenfield stratum movements (Greenfield is an area of land that has not yet had buildings on it, stratum movements means the movement of various soil layers) caused by shield tunnel construction combining an elastic half-space model of mirror source–sink method with the use of modified analytical method. Based on the theoretical formula in this paper, not only can the curve of surface settlement trough be calculated, but also the three-dimensional displacement field of deep soil can be obtained. By comparing vertical and horizontal contour maps of Greenfield stratum movements, good consistency between theoretical formula results and centrifugal test results are shown. This solves the defects and limitations of existing two-dimensional formulas; furthermore, based on this, it is convenient to evaluate the effect on the other skewed underground structures through the elastic foundation beam and other similar methods; therefore, this paper can provide a wide guidance and service for the design and construction of underground engineering in the future.
15N Natural Abundance, Nitrogen and Carbon Pools in Soil-Sorghum System Amended with Natural and NH4+-Enriched Zeolitites
Authors: Ferretti Giacomo , Faccini Barbara , Vittori Antisari Livia , Di Giuseppe Dario , Coltorti Massimo
Published: October 2019

The use of rocks containing high amounts of natural zeolites (zeolitites) as soil amendment has been found as a valuable method for increasing agriculture sustainability. However, the potentialities and the effects of zeolitites on the biogeochemical cycles of nitrogen (N) and carbon (C) have still not been clearly addressed in the literature. The objective of this study was therefore to investigate the N and C pools and 15N distribution in an agricultural soil amended with both natural and NH4+-enriched zeolitites with the aim of understanding their effects on the soil-plant system, during sorghum cultivation, under fertilization reductions. Zeolitites were applied to an agricultural soil both at natural state (5 and 15 kg m−2) and in an enriched state with NH4+ ions from pig slurry (7 kg m−2). Both zeolitites at natural and enriched state increased soil cation exchange capacity and affected microbial biomass, causing an initial decrease of microbial C and N and then a possible increase of fungal population. N-NO3− content was lower in natural zeolitite treatments, that lead to a lower NO3− availability for denitrifying bacteria. Zeolitites slightly affected the fixed N-NH4+ pool. δ15N turnover indicated that N from NH4+-enriched zeolitites remained in the soil until the growing season and that fertilizers partially substituted the fixed pool. Leaf δ15N content indicated that plants assimilated N from NH4+-enriched zeolitites and evidenced a higher fertilization recovery in natural zeolitite treatments. Organic C tended to be higher in all zeolitite treatment rhizospheres. In soils amended with zeolitites at natural state (at both application rates) sorghum yield was similar (+3.7%) to that obtained in the control while it was higher (+13.9%) in the plot amended with NH4+-enriched zeolitites.
Experimental Analysis on the Application of Polymer Matrix Composites Containing Al2O3 for Automotive Lamp Reflector
Authors: Kim Young Shin , Kim Jae Kyung , Na Seung Jun , Jeon Euy Sik
Published: October 2019

As automotive lamps are highly integrated, the heat generated from bulbs reduces the light quantity and lifespan of the bulbs. Numerous studies have been actively conducted worldwide on heat dissipation designs and material modifications for heat release. In this study, an analysis was carried out of the mechanical, thermal, and morphological characteristics of Polybutylene Terephthalate (PBT) and Polyamide (PA6) matrix composites containing alumina filler; further, their flowability and injection moldability were also studied. The PA6 matrix that was subjected to an addition of 60% alumina was selected as the sample. To compare the performances of the selected composites with that of the fog lamp reflector manufactured with conventional PBT, fog lamp reflectors were fabricated. When 60% alumina was added, the thermal conductivity was improved. Thus, the maximum temperature of the lamp reflector was reduced, and the heat was transferred to the surroundings; this was in contrast to the fog lamp reflector fabricated with conventional PBT.
Thermoeconomic Modelling and Parametric Study of a Simple ORC for the Recovery of Waste Heat in a 2 MW Gas Engine under Different Working Fluids
Authors: Ochoa Guillermo Valencia , Peñaloza Carlos Acevedo , Rojas Jhan Piero
Published: October 2019

This paper presents a thermo-economic analysis of a simple organic Rankine cycle (SORC) as a waste heat recovery (WHR) systems of a 2 MW stationary gas engine evaluating different working fluids. Initially, a systematic methodology was implemented to select three organic fluids according to environmental and safety criteria, as well as critical system operational conditions. Then, thermodynamic, exergy, and exergo-economic models of the system were developed under certain defined considerations, and a set of parametric studies are presented considering key variables of the system such as pump efficiency, turbine efficiency, pinch point condenser, and evaporator. The results show the influence of these variables on the combined power of the system (gas engine plus ORC), ORC exergetic efficiency, specific fuel consumption (∆BSFC), and exergo indicators such as the payback period (PBP), levelized cost of energy (LCOE), and the specific investment cost (SIC). The results revealed that heat transfer equipment had the highest exergy destruction cost rates representing 81.25% of the total system cost. On the other hand, sensitivity analyses showed that acetone presented better energetic and exergetic performance when the efficiency of the turbine, evaporator, and condenser pinch point was increased. However, toluene was the fluid with the best results when pump efficiency was increased. In terms of the cost of exergy destroyed by equipment, the results revealed that acetone was the working fluid that positively impacted cost reduction when pump efficiency was improved; and toluene, when turbine efficiency was increased. Finally, the evaporator and condenser pinch point increased all the economic indicators of the system. In this sense, the working fluid with the best performance in economic terms was acetone, when the efficiency of the turbine, pinch condenser, and pinch evaporator was enhanced.
Hazard Analysis for Escalator Emergency Braking System via System Safety Analysis Method Based on STAMP
Authors: Zhou Zitong , Zi Yanyang , Chen Jinglong , An Tong
Published: October 2019

Due to the complex mechanical structure and control process of escalator emergency braking systems (EEBS), traditional hazard analysis based on the event chain model have limitations in exploring component interaction failure in such a complex social-technical system. Therefore, a hazard analysis framework is proposed in this paper for hazard analysis of complex electromechanical systems based on system-theoretic accident model and process (STAMP). Firstly, basic principles of STAMP are introduced and comparison with other hazard analysis methods is conducted, then the safety analysis framework is proposed. Secondly, a study case is performed to identify unsafe control actions of EEBS from control structures, and a specific control diagram is organized to recognize potential example casual scenarios. Next, comparison between fault tree analysis and STAMP for escalator’s overturned accident shows that hazards related to component damaged can be identified by both, while hazards that focus on components interaction can only be identified by STAMP. Besides, single control way and tandem operation process are found to be the obvious causal factors of accidents. Finally, some improvement measures like decibel detection or vibration monitoring of key components are suggested to help the current broken chain detection to trigger the anti-reversal device for a better safe EEBS.
Photon Enhanced Interaction and Entanglement in Semiconductor Position-Based Qubits
Authors: Giounanlis Panagiotis , Blokhina Elena , Leipold Dirk , Staszewski Robert
Published: October 2019

CMOS technologies facilitate the possibility of implementing quantum logic in silicon. In this work, we discuss a minimalistic modelling of entangled photon communication in semiconductor qubits. We demonstrate that electrostatic actuation is sufficient to construct and control desired potential energy profiles along a Si quantum dot (QD) structure allowing the formation of position-based qubits. We further discuss a basic mathematical formalism to define the position-based qubits and their evolution under the presence of external driving fields. Then, based on Jaynes–Cummings–Hubbard formalism, we expand the model to include the description of the position-based qubits involving four energy states coupled with a cavity. We proceed with showing an anti-correlation between the various quantum states. Moreover, we simulate an example of a quantum trajectory as a result of transitions between the quantum states and we plot the emitted/absorbed photos in the system with time. Lastly, we examine the system of two coupled position-based qubits via a waveguide. We demonstrate a mechanism to achieve a dynamic interchange of information between these qubits over larger distances, exploiting both an electrostatic actuation/control of qubits and their photon communication. We define the entanglement entropy between two qubits and we find that their quantum states are in principle entangled.
Glottal Source Contribution to Higher Order Modes in the Finite Element Synthesis of Vowels
Authors: Freixes Marc , Arnela Marc , Socoró Joan , Alías Francesc , Guasch Oriol
Published: October 2019

Articulatory speech synthesis has long been based on one-dimensional (1D) approaches. They assume plane wave propagation within the vocal tract and disregard higher order modes that typically appear above 5 kHz. However, such modes may be relevant in obtaining a more natural voice, especially for phonation types with significant high frequency energy (HFE) content. This work studies the contribution of the glottal source at high frequencies in the 3D numerical synthesis of vowels. The spoken vocal range is explored using an LF (Liljencrants–Fant) model enhanced with aspiration noise and controlled by the R d glottal shape parameter. The vowels [ɑ], [i], and [u] are generated with a finite element method (FEM) using realistic 3D vocal tract geometries obtained from magnetic resonance imaging (MRI), as well as simplified straight vocal tracts of a circular cross-sectional area. The symmetry of the latter prevents the onset of higher order modes. Thus, the comparison between realistic and simplified geometries enables us to analyse the influence of such modes. The simulations indicate that higher order modes may be perceptually relevant, particularly for tense phonations (lower R d values) and/or high fundamental frequency values, F 0 s. Conversely, vowels with a lax phonation and/or low F0s may result in inaudible HFE levels, especially if aspiration noise is not considered in the glottal source model.
Finite Element Modeling of Porous Microstructures With Random Holes of Different-Shapes and -Sizes to Predict Their Effective Elastic Behavior
Authors: Li Haolin , Dong Shuhao , Liu Jiantao , Yu Yaoxiang , Wu Muqing , Zhang Zhengqing
Published: October 2019

Porous materials are promising media for designing medical instruments, drug carriers, and bioimplants because of their excellent biocompatibility, ease of design, and large variation of elastic moduli. In this study, a computational strategy using the finite element method is developed to model the porous microstructures and to predict the relevant elastic moduli considering the actual characteristics of the micropores and their distributions. First, an element-based approach is presented to generate pores of different shapes and sizes according to the experimental observations. Then, a computational scheme to evaluate the effective moduli of macroscopically isotropic porous materials based on their micro-mechanics is introduced. Next, the accuracy of our approach is verified with the analytical solutions of the extreme bounds of the elastic isotropic moduli of a simplified model and with the experimental data available in the literature. Finally, the influence of the shape of pores and their distribution modes are assessed.
Comparing AutoDock and Vina in Ligand/Decoy Discrimination for Virtual Screening
Authors: Vieira Tatiana F. , Sousa Sérgio F.
Published: October 2019

AutoDock and Vina are two of the most widely used protein–ligand docking programs. The fact that these programs are free and available under an open source license, also makes them a very popular first choice for many users and a common starting point for many virtual screening campaigns, particularly in academia. Here, we evaluated the performance of AutoDock and Vina against an unbiased dataset containing 102 protein targets, 22,432 active compounds and 1,380,513 decoy molecules. In general, the results showed that the overall performance of Vina and AutoDock was comparable in discriminating between actives and decoys. However, the results varied significantly with the type of target. AutoDock was better in discriminating ligands and decoys in more hydrophobic, poorly polar and poorly charged pockets, while Vina tended to give better results for polar and charged binding pockets. For the type of ligand, the tendency was the same for both Vina and AutoDock. Bigger and more flexible ligands still presented a bigger challenge for these docking programs. A set of guidelines was formulated, based on the strengths and weaknesses of both docking program and their limits of validation.
A Multi-Physics Modeling-Based Vibration Prediction Method for Switched Reluctance Motors
Authors: Ling Xiao , Tao Jianfeng , Li Bingchu , Qin Chengjin , Liu Chengliang
Published: October 2019

Currently, vibration has been one crucial factor hindering the application of switched reluctance motor (SRM). Hence, it is of crucial importance to predict and suppress this undesirable vibration. This paper proposes a multi-physics analysis-based vibration prediction approach for SRM. It consists of three modules: digital controller and drive circuit module, electromagnetic field module, and mechanical module. In the mechanical module, it not only includes the influence of the stator, but also fully considers the influence of rotor, end cover, bearing, and other components of the motor on the system modal. Moreover, the vibration data under different control strategies are obtained in real time, and data dynamic interaction between the three segments can also be achieved. By combining the electromagnetic forces and the system structure modal, the vibration of SRM can be predicted. Finally, the effectiveness of the proposed method was verified on 12/8 poles, 1.5KW SRM drive system test bench. The results demonstrate that the modal simulation method based on static pre-calculation achieves high accuracy, and the vibration spectrums predicted by the proposed method shows good agreement with the experimental results.
Stolen Voices Is a Slowly Unfolding Eavesdrop on the East Coast of the UK
Authors: Collins Rebecca , Linsley Johanna
Published: October 2019

Stolen Voices is a research enquiry that uses listening as both methodology and material. Stolen Voices develops techniques for ‘listening in’ and eavesdropping to help articulate an epistemology of place through sonic frameworks. A core motivation for the listening is a semi-fictional story we tell ourselves (and anyone else who is listening): an ‘event’ has taken place along the East Coast of the United Kingdom (UK), and we have been tasked with figuring out what has happened. While the specifics of the event might be difficult to pin down, the urgency of the investigation is fuelled by concrete concerns found in the UK edgelands, at the border/margin of the country: the uncertain future of the UK’s relationship with Europe; the effects of climate change on coastal landscapes; the waning of industries like manufacturing and coal extraction; the oil industry in crisis; the rise of global shipping infrastructures. By using a semi-fictional framework, we move away from mapping techniques like data-sonification towards a methodology that embraces gaps and inventive excesses while insisting on the importance of making an account. Through listening, we foster attention to contingencies and indeterminacies and their relationships to prevailing structures and knowledge hierarchies. Stolen Voices asks: what is the relationship between a listener and what is heard? How can listening attune us to the complexities of contemporary political, economic, ecological and social processes? How did we get to where we are now, and how, through listening, can we seek out levers for change? What do the rhythms and atmospheres of specific geographic locations inform or reveal about history? Evolving over several years, in response to what we hear, the investigation necessarily proceeds slowly. In this article, we unfold our methodological processes for the detection of sound, voices, atmosphere and affect. We use creative-critical writing to evidence the construction of a research investigation focused on the act of listening as a spatial practice and necessarily collective endeavour.
Volatile Organic Compounds in a Petrochemical Region in Arid of NW China: Chemical Reactivity and Source Apportionment
Authors: Zhang Xiaoxiao , Ding Xiang , Wang Xinming , Talifu Dilinuer , Wang Guo , Zhang Yanli , Abulizi Abulikemu
Published: October 2019

We measured volatile organic compounds (VOCs) during the heating, non-heating, and sandstorm periods in the air of the Dushanzi district in NW China and investigated their concentrations, chemical reactivity, and sources. The observed concentrations of total VOCs (TVOCs) were 22.35 ± 17.60, 33.20 ± 34.15, and 17.05 ± 13.61 ppbv in non-heating, heating, and sandstorm periods, respectively. C2-C5 alkanes, C2-C3 alkenes, benzene, and toluene were the most abundant species, contributing more than 60% of the TVOCs. Among these VOCs, alkenes such as propene had the highest chemical reactivity, accounting for more than 60% of total hydroxyl radical loss rate (LOH) and ozone formation potential (OFP). Chemical reactivity was the highest in the heating period. The average reaction rate constant (KOH-avg) and average maximum incremental reactivity coefficient (MIR-avg) of the total observed VOCs were (8.72 ± 1.42) × 10−12 cm3/mol∙s and 2.42 ± 0.16 mol/mol, respectively. The results of the source apportionment via the Positive Matrix Factorization (PMF) model showed that coal combustion (43.08%) and industrial processes (38.86%) were the major sources of VOCs in the air of the Dushanzi district. The contribution of coal combustion to VOCs was the highest in the heating period, while that of industrial solvents and oil volatilization was the lowest.
Seasonal Changes in Interclone Variation Following Ozone Exposure on Three Major Gene Pools: An Analysis of Cryptomeria Japonica Clones
Authors: Miyama Takafumi , Tobita Hiroyuki , Uchiyama Kentaro , Yazaki Kenichi , Ueno Saneyoshi , Uemura Akira , Matsumoto Asako , Kitao Mitsutoshi , Izuta Takeshi
Published: October 2019

Recently, there has been a continuous increase in the concentration of tropospheric ozone in urban forests in Japan. Since monoterpenes are precursors to ozone, we need to evaluate the effects of ozone exposure on all tree species that are considered to be sources of monoterpenes. Cryptomeria japonica, which is the most widely planted afforestation tree, is classified into three different gene pools. However, the interclone variation for seasonal changes in the ozone exposure effect has not been evaluated. Thus, free-air ozone enhancement experiments were conducted using three representative clones of C. japonica in the summer and winter. After exposure to twice the ozone concentration in the ambient atmosphere, the effect on the monoterpene emission rate was found to be considerably different among the clones and for the different seasons. The monoterpene emission rate after ozone exposure increased in winter and summer in the native clones (Donden and Yakushima) in the snow area and heavy rain area, respectively. Since monoterpenes are antibacterial substances, each clone adapted sensitivity to stress during each season upon considerable damage. These results suggest that not only differences between tree species but also differences between clones are important for evaluating seasonal variation characteristics after ozone exposure.
Climate Preferences for Tourism: Perceptions Regarding Ideal and Unfavourable Conditions for Hiking in Spain
Authors: Martínez-Ibarra Emilio , Gómez-Martín María , Armesto-López Xosé , Pardo-Martínez Rubén
Published: October 2019

Physical activity is an increasingly frequent part of our leisure time. Within this context, hiking is a popular form of tourism which has a positive impact on the quality of life. In spite of the importance of climate conditions for this recreational activity, relatively little research has been done on hiking from the perspective of climate and tourism. With this in mind in this paper we make the first detailed extensive assessment of climate preferences for the practice of hiking tourism in Spain. To this end a review of the theoretical/methodological body of literature on tourism climatology was conducted together with a survey aimed at evaluating the stated climate preferences of hiking tourists. The results are offered within the framework of international research on climate preferences for a range of tourism activities. The comparative analysis of these results with regard to those obtained in previous research highlights various similarities but also certain factors specific to hiking in Spain. Overall, the climate preferences of hiking tourists are similar to those of other segments of the tourism market in terms of the aesthetic and physical aspects of the climate, although they also have certain specific preferences as regards thermal aspects, especially regarding the optimal daily thermal conditions for hiking. The results obtained are useful for assessing the suitability of the climate for the practice of hiking tourism in Spain and for promoting proper management and planning of this leisure activity in tourist destinations, including the development of climate calendars detailing the most suitable times of the year for hiking at these destinations. These issues will be addressed in future research studies.