bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Operation–Planning Double-Layer Optimization Design Method for Multi-Energy Microgrid Considering Reliability
Authors: Ge Shaoyun , Li Jifeng , Liu Hong , Sun Hao , Wang Yiran
Published: October 2018

A multi-energy microgrid has multiple terminal resources and multiple distributed components for energy production, conversion, and storage. By using this grid, an interconnected network with optimized multiple energy sources can be formed. This type of grid can minimize energy waste while laying the critical foundation for an energy Internet. The multi-energy microgrid must be formed properly to ensure multi-energy coupling and complement. However, critical technologies (e.g., reliability assessment) and configuration planning methods now need further research. In this study, a novel method for the reliability evaluation of a multi-energy supply is proposed, and an operation–planning double-layer optimization design method is investigated that considers reliability. On that basis, the effects of different configuration schemes on economy and reliability are quantitatively analyzed. First, the coupling relationship between multi-energy carriers in a typical multi-energy microgrid is analyzed; subsequently, the energy efficiency and economical models of the key equipment in the grid system are determined. Monte Carlo simulation and the Failure Mode and Effect Analysis (FMEA) method are applied to evaluate the reliability with sorted indicators. A double-layer optimization model is built for a multi-energy microgrid with the optimal configuration. The impact of configuration on the reliability and economical performance of the microgrid system is quantitatively analyzed based on actual calculations. The results obtained here are relative to the capacity, configuration, operation, and energy supply reliability of the multi-energy microgrid, and may serve as the feasible guidelines for future integrated energy systems.
Performance Characteristics of a Seawater Ice-Making Device Using a Scraped Surface Double Tube Evaporator
Authors: Lee Hyun-Kyung , Choi Kwang-Hwan , Yoon Jung-In , Moon Choon-Geun , Jeon Min-Ju , Lee Joon-Hyuk , Lee Kwang-Seok , Son Chang-Hyo
Published: October 2018

In this study, to investigate the performance characteristics of a seawater ice-making device, using a scraped surface double tube evaporator, experiments were conducted under various operating conditions, including inlet temperature and flow rate of seawater, evaporating temperature, and scraper rotation speed. The main results are summarized as follows: (1) The section where stable ice making is possible, is determined by the inlet temperature and the flow rate range of seawater. By controlling the flow rate of seawater, the ice packing factor (IPF) of the device can be adjusted from 0.3 to 14.7%. (2) The IPF increases in cases where the evaporating temperature decreases linearly, until −13 °C. As the temperature of refrigerant that flows into the evaporator changes, the IPF is changed. Consideration is required for these connections. (3) The IPF increases when speeding up the scraper. The minimum rotating speed of the scraper was 350 rpm in these experiments. Optimum operating conditions for the seawater ice slurry maker are established through experiments. These results will be considered as important data for designing a slurry type seawater ice-making device.
Augmentation of Dermal Wound Healing by Adipose Tissue-Derived Stromal Cells (ASC)
Authors: Van Dongen Joris A. , Harmsen Martin C. , Van der Lei Berend , Stevens Hieronymus P.
Published: October 2018

The skin is the largest organ of the human body and is the first line of defense against physical and biological damage. Thus, the skin is equipped to self-repair and regenerates after trauma. Skin regeneration after damage comprises a tightly spatial-temporally regulated process of wound healing that involves virtually all cell types in the skin. Wound healing features five partially overlapping stages: homeostasis, inflammation, proliferation, re-epithelization, and finally resolution or fibrosis. Dysreguled wound healing may resolve in dermal scarring. Adipose tissue is long known for its suppressive influence on dermal scarring. Cultured adipose tissue-derived stromal cells (ASCs) secrete a plethora of regenerative growth factors and immune mediators that influence processes during wound healing e.g., angiogenesis, modulation of inflammation and extracellular matrix remodeling. In clinical practice, ASCs are usually administered as part of fractionated adipose tissue i.e., as part of enzymatically isolated SVF (cellular SVF), mechanically isolated SVF (tissue SVF), or as lipograft. Enzymatic isolation of SVF obtained adipose tissue results in suspension of adipocyte-free cells (cSVF) that lack intact intercellular adhesions or connections to extracellular matrix (ECM). Mechanical isolation of SVF from adipose tissue destructs the parenchyma (adipocytes), which results in a tissue SVF (tSVF) with intact connections between cells, as well as matrix. To date, due to a lack of well-designed prospective randomized clinical trials, neither cSVF, tSVF, whole adipose tissue, or cultured ASCs can be indicated as the preferred preparation procedure prior to therapeutic administration. In this review, we present and discuss current literature regarding the different administration options to apply ASCs (i.e., cultured ASCs, cSVF, tSVF, and lipografting) to augment dermal wound healing, as well as the available indications for clinical efficacy.
Visualizing the Role of 2’-OH rRNA Methylations in the Human Ribosome Structure
Authors: Natchiar S. Kundhavai , Myasnikov Alexander G. , Hazemann Isabelle , Klaholz Bruno P.
Published: October 2018

Chemical modifications of RNA have recently gained new attention in biological sciences. They occur notably on messenger RNA (mRNA) and ribosomal RNA (rRNA) and are important for various cellular functions, but their molecular mechanism of action is yet to be understood in detail. Ribosomes are large ribonucleoprotein assemblies, which synthesize proteins in all organisms. Human ribosomes, for example, carry more than 200 modified nucleotides, which are introduced during biogenesis. Chemically modified nucleotides may appear to be only scarcely different from canonical nucleotides, but modifications such as methylations can in fact modulate their chemical and topological properties in the RNA and alter or modulate the overall translation efficiency of the ribosomes resulting in dysfunction of the translation machinery. Recent functional analysis and high-resolution ribosome structures have revealed a large repertoire of modification sites comprising different modification types. In this review, we focus on 2′-O-methylations (2′-O-Me) and discuss the structural insights gained through our recent cryo electron microscopy (cryo-EM) high-resolution structural analysis of the human ribosome, such as their locations and their influence on the secondary and tertiary structures of human rRNAs. The detailed analysis presented here reveals that ribose conformations of the rRNA backbone differ when the 2′-OH hydroxyl position is methylated, with 3′-endo conformations being the default and the 2′-endo conformations being characteristic in that the associated base is flipped-out. We compare currently known 2′-O-Me sites in human rRNAs evaluated using RiboMethSeq and cryo-EM structural analysis and discuss their involvement in several human diseases.
Addendum: Oil-In-Water Microemulsions as Hosts for Benzothiophene-Based Cytotoxic Compounds: An Effective Combination. Biomimetics 2018, 3, 13
Authors: Theochari Ioanna , Papadimitriou Vassiliki , Papahatjis Demetris , Assimomytis Nikos , Pappou Efthimia , Pratsinis Harris , Xenakis Aristotelis , Pletsa Vasiliki
Published: October 2018

It was brought to our attention that due to recent changes in the regulation that governs the Ph. [...]
Advanced Nanoscale Approaches to Single-(Bio)entity Sensing and Imaging
Authors: Neves Marta Maria Pereira da Silva , Martín-Yerga Daniel
Published: October 2018

Individual (bio)chemical entities could show a very heterogeneous behaviour under the same conditions that could be relevant in many biological processes of significance in the life sciences. Conventional detection approaches are only able to detect the average response of an ensemble of entities and assume that all entities are identical. From this perspective, important information about the heterogeneities or rare (stochastic) events happening in individual entities would remain unseen. Some nanoscale tools present interesting physicochemical properties that enable the possibility to detect systems at the single-entity level, acquiring richer information than conventional methods. In this review, we introduce the foundations and the latest advances of several nanoscale approaches to sensing and imaging individual (bio)entities using nanoprobes, nanopores, nanoimpacts, nanoplasmonics and nanomachines. Several (bio)entities such as cells, proteins, nucleic acids, vesicles and viruses are specifically considered. These nanoscale approaches provide a wide and complete toolbox for the study of many biological systems at the single-entity level.
Intronic miR-744 Inhibits Glioblastoma Migration by Functionally Antagonizing Its Host Gene MAP2K4
Authors: Hübner Max , Hinske Christian Ludwig , Effinger David , Wu Tingting , Thon Niklas , Kreth Friedrich-Wilhelm , Kreth Simone
Published: October 2018

Background: The second intron of Mitogen-Activated Protein Kinase Kinase 4 (MAP2K4), an important hub in the pro-invasive MAPK pathway, harbors miR-744. There is accumulating evidence that intronic micro-RNAs (miRNAs) are capable of either supporting or restraining functional pathways of their host genes, thereby creating intricate regulative networks. We thus hypothesized that miR-744 regulates glioma migration by interacting with its host’s pathways. Methods: Patients’ tumor specimens were obtained stereotactically. MiR-744 was overexpressed in U87, T98G, and primary glioblastoma (GBM) cell lines. Cell mobility was studied using migration and Boyden chamber assays. Protein and mRNA expression was quantified by SDS-PAGE and qRT-PCR. Interactions of miR-744 and 3’UTRs were analyzed by luciferase reporter assays, and SMAD2/3, p38, and beta-Catenin activities by TOP/FOPflash reporter gene assays. Results: As compared to a normal brain, miR-744 levels were dramatically decreased in GBM samples and in primary GBM cell lines. Astrocytoma WHO grade II/III exhibited intermediate expression levels. Re-expression of miR-744 in U87, T98G, and primary GBM cell lines induced focal growth and impaired cell mobility. Luciferase activity of 3’UTR reporter constructs revealed the pro-invasive factors TGFB1 and DVL2 as direct targets of miR-744. Re-expression of miR-744 reduced levels of TGFB1, DVL2, and the host MAP2K4, and mitigated activity of TGFB1 and DVL2 downstream targets SMAD2/3 and beta-Catenin. TGFB1 knock-down repressed MAP2K4 expression. Conclusion: MiR-744 acts as an intrinsic brake on its host. It impedes MAP2K4 functional pathways through simultaneously targeting SMAD-, beta-Catenin, and MAPK signaling networks, thereby strongly mitigating pro-migratory effects of MAP2K4. MiR-744 is strongly repressed in glioma, and its re-expression might attenuate tumor invasiveness.
Reduction Process of Iron Catalyst Precursors for Ammonia Synthesis Doped with Lithium Oxide
Authors: Jedrzejewski Roman , Lendzion-Bielun Zofia
Published: October 2018

Iron catalyst precursors promoted with oxides of calcium, aluminum, and lithium were prepared by a fusion method. Using XRD analysis, it was found that catalyst precursors had a magnetite structure. Lithium oxide, which is dependent on the Fe2+/Fe3+ molar ratio in a catalyst, was built into the magnetite structure as a solid solution and/or formed a separate Li2Fe3O4 phase. Lithium oxide forming the solid solution in magnetite accelerated the magnetite phase reduction. However, it was observed that magnetite, in the presence of lithium oxide, was not reduced to iron directly, but to a transient phase, Li2O·xFeO, where x < 3 was formed, which meant that the reduction to iron was much slower. Activity of the catalysts promoted with lithium oxide increased, while the degree of reduction increased.
CeFe-Based Bead Nanocomposites as Catalysts for Oxidation of Ethylbenzene Reaction
Authors: Pinheiro Andre Luis G. , Oliveira Ana Paula S. , De Sousa Francisco F. , Soares João M. , Saraiva Gilberto D. , Oliveira Alcineia C. , Lang Rossano
Published: October 2018

Oxides with good catalytic performances and more selectivity to valuable chemicals attract numerous research interests for the oxidation of hydrocarbon fuels. Taking advantage of the nanocasting route, CeFe-based nanocomposites were prepared and characterized to achieve superior stability in the oxidation of cyclic compounds. Adding a third metal (Me = Ni2+, Mn2+/Mn3+ or Co2+/Co3+) to the CeFe-based oxide helped the formation of Ce3+/Ce4+, Fe2+/Fe3+ and active couples in the ternary nanocomposites. The solids having a spherical morphology and good textural properties enabled the formation of promising ternary oxide catalysts for the oxidation of ethylbenzene compared with those of binary and single monoxide nanocomposites. The close contact among the Ce3+/Ce4+ and Fe2+/Fe3+ pairs with Ni2+ species provided the formation of a highly stable CeFeNi catalyst with enhanced performance in the oxidation of cyclic compounds such as ethylbenzene, styrene and benzyl alcohol substrates.
Preparation of Magnetic Cross-Linked Amyloglucosidase Aggregates: Solving Some Activity Problems
Authors: Amaral-Fonseca Murilo , Kopp Willian , Giordano Raquel de Lima Camargo , Fernández-Lafuente Roberto , Tardioli Paulo Waldir
Published: October 2018

The preparation of Cross-Linked Enzyme Aggregates (CLEAs) is a simple and cost-effective technique capable of generating insoluble biocatalysts with high volumetric activity and improved stability. The standard CLEA preparation consists of the aggregation of the enzyme and its further crosslinking, usually with glutaraldehyde. However, some enzymes have too low a content of surface lysine groups to permit effective crosslinking with glutaraldehyde, requiring co-aggregation with feeders rich in amino groups to aid the formation of CLEAs. The co-aggregation with magnetic particles makes their handling easier. In this work, CLEAs of a commercial amyloglucosidase (AMG) produced by Aspergillus niger were prepared by co-aggregation in the presence of polyethyleneimine (PEI) or starch with aminated magnetic nanoparticles (MNPs) or bovine serum albumin (BSA). First, CLEAs were prepared only with MNPs at different glutaraldehyde concentrations, yielding a recovered activity of around 20%. The addition of starch during the precipitation and crosslinking steps nearly doubled the recovered activity. Similar recovered activity (around 40%) was achieved when changing starch by PEI. Moreover, under the same conditions, AMG co-aggregated with BSA was also synthesized, yielding CLEAs with very similar recovered activity. Both CLEAs (co-aggregated with MNPs or BSA) were four times more stable than the soluble enzyme. These CLEAs were evaluated in the hydrolysis of starch at typical industrial conditions, achieving more than 95% starch-to-glucose conversion, measured as Dextrose Equivalent (DE). Moreover, both CLEAS could be reused for five cycles, maintaining a DE of around 90%. Although both CLEAs had good properties, magnetic CLEAs could be more attractive for industrial purposes because of their easy separation by an external magnetic field, avoiding the formation of clusters during the filtration or centrifugation recovery methods usually used.
Measuring Food Anticipation in Mice
Authors: Martini Tomaz , Ripperger Jürgen , Albrecht Urs
Published: October 2018

The interplay between the circadian system and metabolism may give animals an evolutionary advantage by allowing them to anticipate food availability at specific times of the day. Physiological adaptation to feeding time allows investigation of animal parameters and comparison of food anticipation between groups of animals with genetic alterations and/or post pharmacological intervention. Such an approach is vital for understanding gene function and mechanisms underlying the temporal patterns of both food anticipation and feeding. Exploring these mechanisms will allow better understanding of metabolic disorders and might reveal potential new targets for pharmacological intervention. Changes that can be easily monitored and that represent food anticipation on the level of the whole organism are a temporarily restricted increase of activity and internal body temperature.
Deploying CPU-Intensive Applications on MEC in NFV Systems: The Immersive Video Use Case
Authors: Cattaneo Giorgio , Giust Fabio , Meani Claudio , Munaretto Daniele , Paglierani Pietro
Published: October 2018

Multi-access Edge Computing (MEC) will be a technology pillar of forthcoming 5G networks. Nonetheless, there is a great interest in also deploying MEC solutions in current 4G infrastructures. MEC enables data processing in proximity to end users. Thus, latency can be minimized, high data rates locally achieved, and real-time information about radio link status or consumer geographical position exploited to develop high-value services. To consolidate network elements and edge applications on the same virtualization infrastructure, network operators aim to combine MEC with Network Function Virtualization (NFV). However, MEC in NFV integration is not fully established yet: in fact, various architectural issues are currently open, even at standardization level. This paper describes a novel MEC in an NFV system which successfully combines, at management level, MEC functional blocks with an NFV Orchestrator, and can neutrally support any “over the top” Mobile Edge application with minimal integration effort. A specific ME app combined with an end-user app for the provision of immersive video services is presented. To provide low latency, CPU-intensive services to end users, the proposed architecture exploits High-Performance Computing resources embedded in the edge infrastructure. Experimental results showing the effectiveness of the proposed architecture are reported and discussed.
Rolling Bearing Diagnosis Based on Composite Multiscale Weighted Permutation Entropy
Authors: Gan Xiong , Lu Hong , Yang Guangyou , Liu Jing
Published: October 2018

In this paper, composite multiscale weighted permutation entropy (CMWPE) is proposed to evaluate the complexity of nonlinear time series, and the advantage of the CMWPE method is verified through analyzing the simulated signal. Meanwhile, considering the complex nonlinear dynamic characteristics of fault rolling bearing signal, a rolling bearing fault diagnosis approach based on CMWPE, joint mutual information (JMI) feature selection, and k-nearest-neighbor (KNN) classifier (CMWPE-JMI-KNN) is proposed. For CMWPE-JMI-KNN, CMWPE is utilized to extract the fault rolling bearing features, JMI is applied for sensitive features selection, and KNN classifier is employed for identifying different rolling bearing conditions. Finally, the proposed CMWPE-JMI-KNN approach is used to analyze the experimental dataset, the analysis results indicate the proposed approach could effectively identify different fault rolling bearing conditions.
The Capacity for Correlated Semantic Memories in the Cortex
Authors: Boboeva Vezha , Brasselet Romain , Treves Alessandro
Published: October 2018

A statistical analysis of semantic memory should reflect the complex, multifactorial structure of the relations among its items. Still, a dominant paradigm in the study of semantic memory has been the idea that the mental representation of concepts is structured along a simple branching tree spanned by superordinate and subordinate categories. We propose a generative model of item representation with correlations that overcomes the limitations of a tree structure. The items are generated through “factors” that represent semantic features or real-world attributes. The correlation between items has its source in the extent to which items share such factors and the strength of such factors: if many factors are balanced, correlations are overall low; whereas if a few factors dominate, they become strong. Our model allows for correlations that are neither trivial nor hierarchical, but may reproduce the general spectrum of correlations present in a dataset of nouns. We find that such correlations reduce the storage capacity of a Potts network to a limited extent, so that the number of concepts that can be stored and retrieved in a large, human-scale cortical network may still be of order 107, as originally estimated without correlations. When this storage capacity is exceeded, however, retrieval fails completely only for balanced factors; above a critical degree of imbalance, a phase transition leads to a regime where the network still extracts considerable information about the cued item, even if not recovering its detailed representation: partial categorization seems to emerge spontaneously as a consequence of the dominance of particular factors, rather than being imposed ad hoc. We argue this to be a relevant model of semantic memory resilience in Tulving’s remember/know paradigms.
Real-Time Road Lane Detection in Urban Areas Using LiDAR Data
Authors: Jung Jiyoung , Bae Sung-Ho
Published: October 2018

The generation of digital maps with lane-level resolution is rapidly becoming a necessity, as semi- or fully-autonomous driving vehicles are now commercially available. In this paper, we present a practical real-time working prototype for road lane detection using LiDAR data, which can be further extended to automatic lane-level map generation. Conventional lane detection methods are limited to simple road conditions and are not suitable for complex urban roads with various road signs on the ground. Given a 3D point cloud scanned by a 3D LiDAR sensor, we categorized the points of the drivable region and distinguished the points of the road signs on the ground. Then, we developed an expectation-maximization method to detect parallel lines and update the 3D line parameters in real time, as the probe vehicle equipped with the LiDAR sensor moved forward. The detected and recorded line parameters were integrated to build a lane-level digital map with the help of a GPS/INS sensor. The proposed system was tested to generate accurate lane-level maps of two complex urban routes. The experimental results showed that the proposed system was fast and practical in terms of effectively detecting road lines and generating lane-level maps.
Investigation on the Suction Reed Valve Motion with Sticky Force in a Refrigerator Compressor
Authors: Zhang Wei , Ji Lantian , Xing Ziwen , Peng Xueyuan
Published: October 2018

The valve motion strongly couples with the differential pressure between the cylinder and the suction and discharge plenum, which has a significant influence on the performance of the refrigerator compressor. To examine the interaction between the pressure and the reed valve motion, this paper presents an experimental investigation into the inner workings of the refrigerator compressor, particularly the p-V diagram and the motion of the suction valve. The refrigerator compressor was modified to conveniently mount the sensors. Three pressure sensors were installed to measure the p-V diagram and pressure pulsation, while a strain gauge was employed to measure the motion of the suction valve. The interaction between the differential pressure and the valve motion were clearly observed from the experimental results. It was found that there was a considerable power loss up to 14.5% in the suction process under experimental conditions. The sticky force of the oil had a significant effect on both the motion of the suction valve and the suction phase of the compressor. The delayed opening of the reed valve increased the amplitude of the pressure pulsation in the suction plenum. The experimental method which integrates the pressure variety and the valve movement proposed in this paper could contribute to the efficient testing and the optimization of the refrigerator compressor.
Coupling Methodology for Studying the Far Field Effects of Wave Energy Converter Arrays over a Varying Bathymetry
Authors: Verao Fernandez Gael , Balitsky Philip , Stratigaki Vasiliki , Troch Peter
Published: October 2018

For renewable wave energy to operate at grid scale, large arrays of Wave Energy Converters (WECs) need to be deployed in the ocean. Due to the hydrodynamic interactions between the individual WECs of an array, the overall power absorption and surrounding wave field will be affected, both close to the WECs (near field effects) and at large distances from their location (far field effects). Therefore, it is essential to model both the near field and far field effects of WEC arrays. It is difficult, however, to model both effects using a single numerical model that offers the desired accuracy at a reasonable computational time. The objective of this paper is to present a generic coupling methodology that will allow to model both effects accurately. The presented coupling methodology is exemplified using the mild slope wave propagation model MILDwave and the Boundary Elements Methods (BEM) solver NEMOH. NEMOH is used to model the near field effects while MILDwave is used to model the WEC array far field effects. The information between the two models is transferred using a one-way coupling. The results of the NEMOH-MILDwave coupled model are compared to the results from using only NEMOH for various test cases in uniform water depth. Additionally, the NEMOH-MILDwave coupled model is validated against available experimental wave data for a 9-WEC array. The coupling methodology proves to be a reliable numerical tool as the results demonstrate a difference between the numerical simulations results smaller than 5% and between the numerical simulations results and the experimental data ranging from 3% to 11%. The simulations are subsequently extended for a varying bathymetry, which will affect the far field effects. As a result, our coupled model proves to be a suitable numerical tool for simulating far field effects of WEC arrays for regular and irregular waves over a varying bathymetry.
Correction: Aljure, M.; Becerra, M.; Karlsson, E.M. Streamer Inception from Ultra-Sharp Needles in Mineral Oil Based Nanofluids Energies 2018, 11, 2064
Authors: Aljure Mauricio , Becerra Marley , Karlsson Mattias E.
Published: October 2018

The authors wish to make the following corrections to their paper [1]:[...]
A CVaR-Robust Risk Aversion Scheduling Model for Virtual Power Plants Connected with Wind-Photovoltaic-Hydropower-Energy Storage Systems, Conventional Gas Turbines and Incentive-Based Demand Responses
Authors: Ju Liwei , Li Peng , Tan Qinliang , Tan Zhongfu , De GejiriFu
Published: October 2018

To make full use of distributed energy resources to meet load demand, this study aggregated wind power plants (WPPs), photovoltaic power generation (PV), small hydropower stations (SHSs), energy storage systems (ESSs), conventional gas turbines (CGTs) and incentive-based demand responses (IBDRs) into a virtual power plant (VPP) with price-based demand response (PBDR). Firstly, a basic scheduling model for the VPP was proposed in this study with the objective of the maximum operation revenue. Secondly, a risk aversion model for the VPP was constructed based on the conditional value at risk (CVaR) method and robust optimization theory considering the operating risk from WPP and PV. Thirdly, a solution methodology was constructed and three cases were considered for comparative analyses. Finally, an independent micro-grid on an industrial park in East China was utilized for an example analysis. The results show the following: (1) the proposed risk aversion scheduling model could cope with the uncertainty risk via a reasonable confidence degree β and robust coefficient Γ. When Γ ≤ 0.85 or Γ ≥ 0.95, a small uncertainty brought great risk, indicating that the risk attitude of the decision maker will affect the scheduling scheme of the VPP, and the decision maker belongs to the risk extreme aversion type. When Γ ∈ (0.85, 0.95), the decision-making scheme was in a stable state, the growth of β lead to the increase of CVaR, but the magnitude was not large. When the prediction error e was higher, the value of CVaR increased more when Γ increased by the same magnitude, which indicates that a lower prediction accuracy will amplify the uncertainty risk. (2) when the capacity ratio of (WPP, PV): ESS was higher than 1.5:1 and the peak-to-valley price gap was higher than 3:1, the values of revenue, VaR, and CVaR changed slower, indicating that both ESS and PBDR can improve the operating revenue, but the capacity scale of ESS and the peak-valley price gap need to be set properly, considering both economic benefits and operating risks. Therefore, the proposed risk aversion model could maximize the utilization of clean energy to obtain higher economic benefits while rationally controlling risks and provide reliable decision support for developing optimal operation plans for the VPP.
Assessment of the Power Output of a Two-Array Clustered WEC Farm Using a BEM Solver Coupling and a Wave-Propagation Model
Authors: Balitsky Philip , Verao Fernandez Gael , Stratigaki Vasiliki , Troch Peter
Published: October 2018

One of the key challenges in designing a Wave Energy Converter (WEC) farm is geometrical layout, as WECs hydrodynamically interact with one another. WEC positioning impacts both the power output of a given wave-energy project and any potential effects on the surrounding areas. The WEC farm developer must seek to optimize WEC positioning to maximize power output while minimizing capital cost and any potential deleterious effects on the surrounding area. A number of recent studies have shown that a potential solution is placing WECs in dense arrays of several WECs with space between individual arrays for navigation. This innovative arrangement can also be used to reduce mooring and cabling costs. In this paper, we apply a novel one-way coupling method between the NEMOH BEM model and the MILDwave wave-propagation model to investigate the influence of WEC array separation distance on the power output and the surrounding wave field between two densely packed WEC arrays in a farm. An iterative method of applying the presented one-way coupling to interacting WEC arrays is used to compute the wave field in a complete WEC farm and to calculate its power output. The notion of WEC array ‘independence’ in a farm from a hydrodynamic point of view is discussed. The farm is modeled for regular and irregular waves for a number of wave periods, wave incidence angles, and various WEC array separation distances. We found strong dependency of the power output on the wave period and the wave incidence angle for regular waves at short WEC array–array separation distances. For irregular wave operational conditions, a large majority of WEC array configurations within a WEC farm were found to be hydrodynamically ‘independent’.
Study on Insulation Breakdown Characteristics of Printed Circuit Board under Continuous Square Impulse Voltage
Authors: Zhou Quan , Wen Mingqian , Xiong Taotao , Jiang Tianyan , Zhou Ming , Ouyang Xi , Xing Lai
Published: October 2018

The widely distributed interconnects in printed circuit boards (PCBs) easily couple with high voltage under the action of electromagnetic pulses, which leads to insulation failure. In this study, the dielectric breakdown characteristics of four typical PCBs are studied under continuous square impulse voltage conditions. First, the electric field distribution in the four electrode models is simulated with the ANSYS software (ANSYS Maxwell 17.0). Electric field simulation results show the weak area of electric field distribution. On this basis, the possible breakdown patterns of PCB are analyzed. Second, the influence of factors, such as temperature, pulse duty ratio, interconnect insulation distance, and air pressure, on PCB breakdown voltage is studied through a breakdown test on the PCBs. Results show that the discharge between the single-layer electrodes of the PCBs is surface discharge, and the breakdown is that of a “gas–solid composite medium”. Meanwhile, the breakdown of a double-layer PCB is solid breakdown. Finally, scanning electron microscopy (SEM) produced by Tescan (Brno, Czech Republic) is performed to study the carbonization channel after PCB breakdown. SEM results reveal that the PCB carbonization channel is influenced by temperature and pressure in varying degrees.
Effect of EV Movement Schedule and Machine Learning-Based Load Forecasting on Electricity Cost of a Single Household
Authors: Arens Stefan , Derendorf Karen , Schuldt Frank , Maydell Karsten , Agert Carsten
Published: October 2018

An energy management system (EMS) for a household energy system is proposed in this paper, which is composed of a photovoltaic (PV) generator , a home energy storage (HES), an electric vehicle (EV), an electrical household load and a grid connection, with 24 h operation horizon. The EMS objective is to reduce the electricity cost of the household by using a linear optimization algorithm. Two different EV schedules are utilized for simulations. One mainly describes rides to work and the other describes rides in a domestic context, such as rides to a supermarket. A forecast algorithm for the electrical load of the household, based on k-means clustering and an artificial neural network, is evaluated and integrated into the EMS to realistically represent the household’s load profile. It is shown that the developed forecast algorithm performs better than two of the benchmarks. Another finding is that the more storage is available at PV-production intervals, the higher the effect of forecast uncertainties and the lower the electricity cost of the household, disregarding the investment cost.
A Practical Load-Source Coordinative Method for Further Reducing Curtailed Wind Power in China with Energy-Intensive Loads
Authors: Zhu Dandan , Liu Wenying , Hu Yang , Wang Weizhou
Published: October 2018

Large-scale wind power farms in China are suffering from large amounts of curtailed wind power in the conventional dispatching mode. Energy-intensive loads have great potential in providing service regulation to help consume the curtailed wind power. However, constrained by technical limitations, the regulating power of energy-intensive loads cannot fully follow the fluctuating wind power. This would result in insufficient utilization of the regulation capability of energy-intensive loads, which limits the promotion in consumption of curtailed wind power brought by load-source coordination. With this concern, a brand new method for further consuming the curtailed wind power, which involves using coal-fueled units to provide ancillary regulation for the coordination of energy-intensive loads and wind power is presented, and a corresponding bi-level coordinative model is also established. The first level of optimization is intended to maximize the consumption of curtailed wind power with minimum ancillary regulation energy. The second level of optimization is to allocate the ancillary regulating power with minimum regulation cost. Wind power consumption was increased by 3,369.25 MWh and utilization rate of energy-intensive loads was promoted to 100% in the case analysis, which verifies the effectiveness of the proposed method.
Hierarchical Control of Nonlinear Active Four-Wheel-Steering Vehicles
Authors: Tian Jie , Ding Jie , Tai Yongpeng , Chen Ning
Published: October 2018

A new type of hierarchical control is proposed for a four-wheel-steering (4WS) vehicle, in which both the sideslip angle and yaw rate feedback are used, and the saturation of the control variables (i.e., the front and rear steering angles) is considered. The nonlinear three degrees of freedom (3DOF) 4WS vehicle model is employed to describe the uncertainties originating from the operating situations. Further, a normal front-wheel-steering (2WS) vehicle with a drop filter of the sideslip angle is selected as the reference model. The inputs for the rear and front steering angles of the linear 2DOF 4WS, required to achieve the performances described by the reference model, are obtained and controlled by the upper controller. Further, the lower controller is designed to eliminate the state error between the linear 2DOF and nonlinear 3DOF 4WS vehicle models. The simulation results of several vehicle models with/without the controller are presented, and the robustness of the hierarchical control system is analyzed. The simulation results indicate that using the proposed hierarchical controller yields the same performance between the nonlinear 4WS vehicle and the reference model, in addition to exhibiting good robustness.
Factors Explaining the Interest of Adult Offspring in Succeeding Their Parents as Forest Owners
Authors: Staal Wästerlund Dianne
Published: October 2018

In the past, Swedish ownership of the forest estate was predominantly passed on by parents to their descendants. However, a general societal change has given successors a larger say in decisions on such matters. Their willingness to become forest owners has, therefore, become an important factor for who will own the forest in the future. To study what factors explain adult descendants’ interest in taking over as forest owners, this study determined how adult children, who expressed a willingness to take over their parents’ forest estate, were different from those who were not willing. Members of the Northern Forest Owner Association in Sweden were asked to provide contact addresses of their children, in the age group 30 to 50 years old. The logistic regression analysis of the 249 participating offspring respondents revealed several significant factors. Offspring who helped their parents with the management of the estate were more likely to be willing to take it over, showing that developing into a forest owner remains a socialization process that starts with practical work. Values, such as the respondents’ attitude towards maintaining a forest ownership tradition, as well as the interest in forest income, hunting, and fishing, were also found to be factors affecting the willingness to take over. The results also indicate that the socialization process is still gender-biased, and that the distance between a descendants’ present home and the forest estate is a factor that mattered.
High-Pressure Aging of Asymmetric Torlon® Hollow Fibers for Helium Separation from Natural Gas
Authors: Dibrov George , Ivanov Mikhail , Semyashkin Mikhail , Sudin Vladislav , Kagramanov Georgy
Published: October 2018

Membrane separation for helium extraction from natural gas gained increased interest recently. Several vendors offer membrane elements for helium extraction, although data on their performance and operating experience are unpublished. The aim of this work was to obtain and study the separation performance of asymmetric hollow-fiber membrane element from commercial polyamide-imide Torlon®, in conditions close to the industrial process of helium extraction from natural gas. A membrane element with an active area of 0.177 m2, a helium permeance of 100 l(STP)/(m2·h·bar), and a selectivity α(He/CH4) = 340 was produced. This corresponds to a selective layer thickness of 82.3 nm, which was confirmed by SEM and resistance model calculations. The obtained membrane element was employed to decrease the concentration of helium in its binary mixture with methane from 0.4% to 0.05%. A relationship of separation characteristics from transmembrane pressure is also presented. At 70 bar and a stage cut of 2.7%, the feed flow rate was 0.16 m3(STP)/h, which yielded a helium permeate concentration of 14.7%. At 80 bar, a decrease in permeance to 60 l(STP)/(m2·h·bar) and in selectivity to 240 was observed. It was shown that the main reason for aging was the increased support resistance, due to a partial compaction of pores with a radius of less than 15 nm.
Preparation of Chitosan-Coated Poly(L-Lactic Acid) Fibers for Suture Threads
Authors: Komoto Daiki , Ikeda Ryoka , Furuike Tetsuya , Tamura Hiroshi
Published: October 2018

Poly(L-lactic acid) (PLA) is a biodegradable fiber, and a promising material for use in biomedical applications. However, its hydrophobicity, low hydrolyzability, and poor cell adhesion can be problematic in some cases; consequently, the development of improved PLA-based materials is required. In this study, chitosan-coated (CS-coated) PLA was prepared by plasma treatment and the layer-by-layer (LBL) method. Plasma treatment prior to CS coating effectively hydrophilized and activated the PLA surface. The LBL method was used to increase the number of CS and sodium alginate (SA) coating layers by electrostatically superposing alternating anionic and cationic polymers. The prepared fibers were characterized by tensile testing, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), nitrogen analysis and degradation testing, which revealed that the 100 W plasma treatment for 60 s was optimum, and that plasma treatment and the LBL method effectively coated CS onto the PLA fibers. The existence or not of a coating on the PLA fiber did not appear to influence the degradation of the fiber, which is ascribable to the extremely thin coating, as evidenced by nitrogen analysis and SEM. The CS-coated PLA fibers were prepared without damaging the PLA surface and can be used in biomaterial applications such as suture threads.
Differential Diffusivity Effects in Reactive Convective Dissolution
Authors: Loodts V. , Saghou H. , Knaepen B. , Rongy L. , De Wit A.
Published: October 2018

When a solute A dissolves into a host fluid containing a reactant B, an A + B → C reaction can influence the convection developing because of unstable density gradients in the gravity field. When A increases density and all three chemical species A, B and C diffuse at the same rate, the reactive case can lead to two different types of density profiles, i.e., a monotonically decreasing one from the interface to the bulk and a non-monotonic profile with a minimum. We study numerically here the nonlinear reactive convective dissolution dynamics in the more general case where the three solutes can diffuse at different rates. We show that differential diffusion can add new dynamic effects like the simultaneous presence of two different convection zones in the host phase when a non-monotonic profile with both a minimum and a maximum develops. Double diffusive instabilities can moreover affect the morphology of the convective fingers. Analysis of the mixing zone, the reaction rate, the total amount of stored A and the dissolution flux further shows that varying the diffusion coefficients of the various species has a quantitative effect on convection.
Evolve Filter Stabilization Reduced-Order Model for Stochastic Burgers Equation
Authors: Xie Xuping , Bao Feng , Webster Clayton G.
Published: October 2018

In this paper, we introduce the evolve-then-filter (EF) regularization method for reduced order modeling of convection-dominated stochastic systems. The standard Galerkin projection reduced order model (G-ROM) yield numerical oscillations in a convection-dominated regime. The evolve-then-filter reduced order model (EF-ROM) aims at the numerical stabilization of the standard G-ROM, which uses explicit ROM spatial filter to regularize various terms in the reduced order model (ROM). Our numerical results are based on a stochastic Burgers equation with linear multiplicative noise. The numerical result shows that the EF-ROM is significantly better than G-ROM.
Testing the Sensitivity of Potential Panelists for Wine Taint Compounds Using a Simplified Sensory Strategy
Authors: McKay Marianne , Bauer Florian F. , Panzeri Valeria , Buica Astrid
Published: October 2018

The odor detection threshold (ODT) of a compound is the lowest concentration at which individuals can reliably perceive a difference between a sample and its corresponding control, with 50% performance above chance. Wine is a complex matrix, and ODTs used in studies on wine can be based on inappropriate matrices and informal sensory methodologies. Formal studies confirming ODTs in wine are relatively scarce in the literature, and are complex and expensive to carry out. In this study, the sensitivity of panelists to previously published ODTs for five compounds: Guaiacol, o-cresol and 4-ethyl phenol, 3-isobutyl-2-methoxypyrazine (IBMP), and 2,4,6-trichloroanisole (TCA) associated with off-flavor/taint issues in wine, was investigated. The study was carried out in partially de-aromatized young Shiraz wine (unwooded) using a simplified version of the formal sensory approach. A triangle test in triplicate was carried out with 34 panelists, at the ODT for each compound, in one day. The study explored whether previous training affected panelists’ sensitivity for threshold differences. Results showed that samples spiked with volatile phenols were significantly different (p = 0.01) to controls. The spiked TCA and IBMP samples were not significantly different from the control in either case. Judges were better able to detect compounds if they had prior experience or training in wine evaluation. Despite some limitations, this pragmatic approach may be useful when carrying out sensory studies with fairly limited resources and within tight timelines, as it provides helpful information on panel members and detection thresholds for a specific matrix.
Planetary Nebulae Shaped by Common Envelope Evolution
Authors: Frank Adam , Chen Zhuo , Reichardt Thomas , De Marco Orsola , Blackman Eric , Nordhaus Jason
Published: October 2018

The morphologies of planetary nebula have long been believed to be due to wind shaping processes in which a “fast wind” from the central star impacts a previously ejected envelope. It is assumed that asymmetries existing in the “slow wind” envelope would lead to inertial confinement, shaping the resulting interacting wind flow. We present new results demonstrating the effectiveness of Common Envelope Evolution (CEE) at producing aspherical envelopes which, when impinged upon by a spherical fast stellar wind, produce highly bipolar, jet-like outflows. We have run two simple cases using the output of a single PHANTOM SPH CEE simulation. Our work uses the Adaptive Mesh Refinement code AstroBEAR to track the interaction of the fast wind and CEE ejecta allows us to follow the morphological evolution of the outflow lobes at high resolution in 3-D. Our two models bracket low and high momentum output fast winds. We find the interaction leads to highly collimated bipolar outflows. In addition, the bipolar morphology depends on the fast wind momentum injection rate. With this dependence comes the initiation of significant symmetry breaking between the top and bottom bipolar lobes. Our simulations, though simplified, confirm the long-standing belief that CEE can plan a major role in PPN and PN shaping. These simulations are intended as an initial exploration of the post-CE/PPN flow patterns that can be expected from central source outflows and CE ejecta.