bluuebunny/crossref_metadata_2025 huggingface dataset:
Organ-on-chips made of blood: endothelial progenitor cells from blood reconstitute vascular thromboinflammation in vessel-chips
Authors: Mathur Tanmay , Singh Kanwar Abhay , R. Pandian Navaneeth K. , Tsai Shu-Huai , Hein Travis W. , Gaharwar Akhilesh K. , Flanagan Jonathan M. , Jain Abhishek
Published: June 2019

Organ-on-chips made of blood: personalized medicine with microfluidics.
Functionalized branched polymers: promising immunomodulatory tools for the treatment of cancer and immune disorders
Authors: Moura Liane I. F. , Malfanti Alessio , Peres Carina , Matos Ana I. , Guegain Elise , Sainz Vanessa , Zloh Mire , Vicent María J. , Florindo Helena F.
Published: June 2019

The review focus on branched polymers as promising delivery systems with immunomodulatory properties against cancer and infectious diseases. It covers their physicochemical properties and on how those can be tailored to modulate the immune system.
Bi-continuous pattern formation in thin films via solid-state interfacial dealloying studied by multimodal characterization
Authors: Zhao Chonghang , Kisslinger Kim , Huang Xiaojing , Lu Ming , Camino Fernando , Lin Cheng-Hung , Yan Hanfei , Nazaretski Evgeny , Chu Yong , Ravel Bruce , Liu Mingzhao , Chen-Wiegart Yu-chen Karen
Published: June 2019

Solid-state interfacial dealloying creates bi-continuous nanostructured thin films with 3D interconnected morphology, revealed by multimodal characterization, offering potential applications in catalysis, biomedical sensing and energy storage.
Anticancer and biological properties of a Zn-2,6-diacetylpyridine bis(thiosemicarbazone) complex
Authors: Yu Ping , Deng Jungang , Cai Jinhua , Zhang Zhenlei , Zhang Juzheng , Hamid Khan Muhammad , Liang Hong , Yang Feng
Published: June 2019

Herein, to develop a multi-target anticancer metal agent and achieve a “1 + 1 > 2” pharmaceutical effect, we rationally designed and synthesized five complexes (C1–C5) by synergistically exploiting the properties of Zn(ii) and a series of modified 2,6-diacetylpyridine bis(thiosemicarbazone) ligands. By investigating the structure–activity relationships, we found that the binuclear Zn(ii) complex (C5) acts against human bladder cancer cells (T-24) with significant cytotoxicity. We subsequently determined the multiple anticancer mechanisms of C5 to T-24 cells, including inhibiting the activity of topoisomerase I (Topo I), blocking the cell cycle in the S phase, and inducing apoptosis and autophagy in T-24 cells. Furthermore, C5 inhibited the migration of T-24 cells and showed a significant cytostatic effect in the T-24 3D spheroid model.
Mechanistic and thermodynamic aspects of a pyrene-based fluorescent probe to detect picric acid
Authors: Kundu Bidyut Kumar , Pragti Pragti , Reena Reena , Mobin Shaikh M. , Mukhopadhyay Suman
Published: June 2019

Thermodynamic investigation of picric acid sensing using a pyrene-based fluorescent probe.
Cycloaddition reactions on epitaxial graphene
Authors: Denis Pablo A. , Pereyra Huelmo C. , Iribarne Federico
Published: June 2019

By means of first principles calculations we studied the occurrence of cycloaddition reactions on the buffer layer of silicon carbide. Interestingly, the presence of the substrate favors the 1,3 cycloaddition instead of the [2+2] or [4+2] ones.
Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers
Authors: Brem Samuel , Zipfel Jonas , Selig Malte , Raja Archana , Waldecker Lutz , Ziegler Jonas D. , Taniguchi Takashi , Watanabe Kenji , Chernikov Alexey , Malic Ermin
Published: June 2019

The reduced dielectric screening in atomically thin transition metal dichalcogenides allows to study the hydrogen-like series of higher exciton states in optical spectra even at room temperature.
Thermo-tunable colorimetric detection of mercury(ii) ions driven by the temperature-dependent assembly and disassembly of a block copolymer
Authors: Kim Hye-Jin , Lee Hyung-il
Published: June 2019

A thermo-responsive double-hydrophilic block copolymer (DHBC) was synthesized for the thermo-tunable detection of mercury(ii) ions modulated by a temperature-dependent morphological transition between unimers and micellar aggregates.
Synthesis of aminoboronic acid derivatives: an update on recent advances
Authors: Šterman Andrej , Sosič Izidor , Gobec Stanislav , Časar Zdenko
Published: June 2019

Aminoboronic acids and their derivatives are particularly useful as drugs, probes and synthons. Recent developments in their synthesis are highlighted.
Rapid glycosylation of 2′-benzoylphenyl glycosides promoted by TfOH
Authors: Liu Da-Ke , Xiong De-Cai , Wu Xia , Li Qin , Ye Xin-Shan
Published: June 2019

A new glycosylation protocol based on 2′-benzoylphenyl glycosides has been developed. These glycosyl donors could be rapidly activated by TfOH at room temperature.
Evaluation of anti-EGFR-iRGD recombinant protein with GOLD nanoparticles: synergistic effect on antitumor efficiency using optimized deep neural networks
Authors: Chandra Kaushik Aman , Wang Yan-Jing , Wang Xiangeng , Kumar Ajay , Singh Satya P. , Pan Cheng-Tang , Shiue Yow-Ling , Wei Dong-Qing
Published: June 2019

NP screening through a deep learning approach against Anti-EGFR and validation through docking with AuNP. Biochemical pathway and simulation of AuNP with Anti-EGFR and further implementation in biological circuits.
Influence of defect on the electrical and optical properties of A-site non-stoichiometry Ca0.67La0.22□0.11Ti(1−x)CrxO3−δ perovskite
Authors: Hassen A. B. , Rhouma F. I. H. , Daoudi M. , Dhahri J. , Zaidi M. , Abdelmoula N.
Published: June 2019

An investigation of the real part of permittivity for the compositions (a) x = 0 and (b) x = 0.1 solid solution Ca0.67La0.22□0.11Ti(1−x)CrxO3−δ ceramics.
Microfluidic approaches for accessing thermophysical properties of fluid systems
Authors: Gavoille Theo , Pannacci Nicolas , Bergeot Ghislain , Marliere Claire , Marre Samuel
Published: June 2019

Thermophysical properties of fluid systems under high pressure and high temperature conditions are highly desirable as they are used in many industrial processes both from a chemical engineering point of view and to push forward the development of modeling approaches.
A simple vaporous probe with atomic-scale sensitivity to structural ordering and orientation of molecular assembly
Authors: Cheng Han-Wen , Wu Zhi-Peng , Yan Shan , Li Jing , Shan Shiyao , Wang Lichang , Porter Marc D. , Zhong Chuan-Jian
Published: June 2019

We report a simple combination of vaporous probe and quartz crystal microbalance with atomic-scale sensitivity to interfacial ordering and orientation.
The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H2S)n]+ (n = 1–4) radical cation clusters
Authors: Wang Dandan , Hattori Keigo , Fujii Asuka
Published: June 2019

IR spectroscopy of [benzene-(H2S)n]+ (n = 1–4) elucidates the change of the positive charge accommodation motif from the S∴π hemibond to the S∴S hemibond.
Transient evolution of flow profiles in a shear banding wormlike micellar solution: experimental results and a comparison with the VCM model
Authors: Mohammadigoushki Hadi , Dalili Alireza , Zhou Lin , Cook Pamela
Published: June 2019

In this paper, we report formation of a transient negative elastic recoil in a shear banding wormlike micellar fluid based on CTAB/NaSal.
Spatial separation of dual-cocatalysts on one-dimensional semiconductors for photocatalytic hydrogen production
Authors: Khan Khakemin , Tao Xiaoping , Zhao Yue , Zeng Bin , Shi Ming , Ta Na , Li Jianming , Jin Xu , Li Rengui , Li Can
Published: June 2019

Light-driven hydrogen production using semiconductor photocatalysts has gained much interest.
Exploring the charge reactions in a Li–O2 system with lithium oxide cathodes and nonaqueous electrolytes
Authors: Zhang Tao , Amine Rachid , Bi Xuanxuan , Qin Yan , Li Matthew , Al-Hallaj Said , Huo Fengwei , Lu Jun , Amine Khalil
Published: June 2019

In this paper, we demonstrate the decomposition mechanism of lithium peroxide and lithium oxide in different electrolytes.
Underlying mechanism of CO2 adsorption onto conjugated azacyclo-copolymers: N-doped adsorbents capture CO2 chiefly through acid–base interaction?
Authors: Qi Shi-Chao , Wu Ju-Kang , Lu Jie , Yu Guo-Xing , Zhu Rong-Rong , Liu Yu , Liu Xiao-Qin , Sun Lin-Bing
Published: June 2019

Induction force is demonstrated to account for the improved CO2 adsorption by N-doped sites of adsorbents instead of acid–base interaction.
Ambient electrohydrogenation of N2 for NH3 synthesis on non-metal boron phosphide nanoparticles: the critical role of P in boosting the catalytic activity
Authors: Zhu Xiaojuan , Wu Tongwei , Ji Lei , Li Chengbo , Wang Ting , Wen Shaohua , Gao Shuyan , Shi Xifeng , Luo Yonglan , Peng Qiling , Sun Xuping
Published: June 2019

As a non-metal electrocatalyst for the N2 reduction reaction, boron phosphide nanoparticles offer a high NH3 yield of 26.42 μg h−1 mgcat.−1 and a high faradaic efficiency of 12.7% at –0.60 V vs. the reversible hydrogen electrode in 0.1 M HCl.
Experimental and theoretical understanding on electrochemical activation and inactivation processes of Nb3O7(OH) for ambient electrosynthesis of NH3
Authors: Wu Tianxing , Han Miaomiao , Zhu Xiaoguang , Wang Guozhong , Zhang Yunxia , Zhang Haimin , Zhao Huijun
Published: June 2019

Our experimental and theoretical calculation results revealed the electrochemical activation and inactivation processes of ultrafine Nb3O7(OH) nanoparticle catalysts for electrocatalytic N2 reduction to produce NH3 under ambient conditions.
Controlled delivery of recombinant human bone morphogenetic protein-2 by using glucose-sensitive core–shell nanofibers to repair the mandible defects in diabetic rats
Authors: Xiao Yu , Gong Tao , Jiang Ying , Bao Chongyun , Zhou Shaobing
Published: June 2019

Glucose-sensitive core–shell nanofibers that can self-regulate the rhBMP-2 release and enhance a diabetic rat's mandible regeneration capability.
A possibly highly conducting state in an optically excited molecular crystal
Authors: Naito Toshio , Karasudani Tomoaki , Yamamoto Ryoma , Zhang Ming Yang , Yamamoto Takashi
Published: June 2019

Optical and reversible control between metal-like and semiconducting properties.
A review on inkjet printing of nanoparticle inks for flexible electronics
Authors: Nayak Laxmidhar , Mohanty Smita , Nayak Sanjay Kumar , Ramadoss Ananthakumar
Published: June 2019

The recent progress, challenges and promising future of design and synthesis of inks and device fabrication by inkjet printing are reviewed and discussed.
Combining GeO2 passivation strategies aiming at dielectric layers with superior properties on germanium substrates
Authors: Etcheverry Louise Patron , Boudinov Henri Ivanov , Vieira Soares Gabriel , Radtke Cláudio
Published: June 2019

Hf and N incorporation in GeO2 suppresses its volatilization and further oxidation of the Ge substrate.
Nanowire-assisted self-assembly of one-dimensional nanocrystal superlattice chains
Authors: Ji Yongqiang , Wang Minqiang , Yang Zhi , Ji Shangdong , Qiu Hengwei
Published: June 2019

Ordered and self-assembled nanocrystal superstructures have attracted intense attention due to their ability to transfer unique nanoscale properties to large scale.
Novel robust ion-specific responsive photonic hydrogel elastomers
Authors: Liu Wenzhao , Li Li , Liu Suni , Liu Bing , Wu Zhaoyang , Deng Jianru
Published: June 2019

Embedded photonic hydrogels that can change structural color as a result of external stimuli have shown great potential for various applications, but their practical applications have been limited due to the poor mechanical properties of materials.
G-CSF partially mediates bone loss induced by Staphylococcus aureus infection in mice
Authors: Hou Yilong , Qin Hanjun , Jiang Nan , Liu Guanqiao , Wu Hangtian , Bai Lang , Yu Bin , Zhang Xianrong
Published: June 2019

Bone loss in Staphylococcus aureus (S. aureus) osteomyelitis poses a serious challenge to orthopedic treatment. The present study aimed to elucidate how S. aureus infection in bone might induce bone loss. The C57BL/6 mice were injected with S. aureus (106 CFU/ml, 100 μl) or with the same amount of vehicle (control) via the tail vein. Microcomputed tomography (microCT) analysis showed bone loss progressing from week 1 to week 5 after infection, accompanied by a decreased number of osteocalcin-positive stained osteoblasts and the suppressed mRNA expression of Runx2 and osteocalcin. Transcriptome profiles of GSE30119 were downloaded and analyzed to determine the differences in expression of inflammatory factors between patients with S. aureus infected osteomyelitis and healthy controls, the data showed significantly higher mRNA expression of granulocyte colony-stimulating factor (G-CSF) in the whole blood from patients with S. aureus infection. Enzyme-linked immunosorbent assay (ELISA) analysis confirmed an increased level of G-CSF in the bone marrow and serum from S. aureus infected mice, which might have been due to the increased amount of F4/80+ macrophages. Interestingly, G-CSF neutralizing antibody treatment significantly rescued the bone loss after S. aureus infection, as evidenced by its roles in improving BV/TV and preserving osteocalcin- and osterix-positive stained cells. Importantly, we found that G-CSF level was significantly up-regulated in the serum from osteomyelitis patients infected by S. aureus. Together, S. aureus infection might suppress the function of osteoblastic cells and induce progressive bone loss by up-regulating the level G-CSF, suggesting a therapeutic potential for G-CSF neutralization in combating bone loss in S. aureus osteomyelitis.
Letter Verbal Fluency in Spanish-, Basque-, and Catalan-Speaking Individuals: Does the Selection of the Letters Influence the Outcome?
Authors: Olabarrieta-Landa Laiene , Benito-Sánchez Itziar , Alegret Montserrat , Gailhajanet Anna , Landa Torre Esther , López-Mugartza Juan Carlos , Arango-Lasprilla Juan Carlos
Published: June 2019

Purpose

The aim of this study was to compare Basque and Catalan bilinguals' performance on the letter verbal fluency test and determine whether significant differences are present depending on the letters used and the language of administration.

Method

The sample consisted of 87 Spanish monolinguals, 139 Basque bilinguals, and 130 Catalan bilinguals from Spain. Participants completed the letter verbal fluency test using the letters F, A, S, M, R, P, and E.

Results

Bilinguals scored higher on the letter verbal fluency test when they were tested in Spanish than in Basque or Catalan. No performance differences were found according to native language or dialects within Basque participants. Catalans with Spanish as their native language scored lower on the letter F compared to those who grew up speaking Catalan and Spanish. The suggested letters to use with Basque speakers are A, E, and B; the suggested letters to use with Catalan speakers are P, F, and M; and the suggested letters to use with Spanish speakers are M, R, and P.

Conclusion

Selecting appropriate stimuli depending on the language of testing is the first crucial step to assess verbal fluency and thus possible frontal lobe functioning impairment.
Electric spring controller design for distribution network loaded by electric vehicles
Authors: Javaid Muhammad S. , Sabir Adeel , Abido Mohammad A. , Bouchekara Houssem R.E.H.
Published: June 2019

Although electric vehicles (EVs) offer a viable mean of commuting, their widespread penetration can have adverse effects on the current electrical distribution networks due to voltage drop and overloading of distribution transformers. In this work, a novel control scheme is proposed and implemented to support the voltage profile of a typical distribution network loaded by EVs. Electric spring (ES), a real/reactive power compensator, is driven by the proposed controller to provide voltage support under dynamic loading conditions. In the proposed scheme, the ES reference voltage is continuously determined and then compared with its instantaneous output voltage in a closed‐loop configuration. The proposed controller is tested under various loading conditions both through simulations and digital implementation in the hardware‐in‐the‐loop configuration to evaluate its overall performance. Results show that ES equipped with the proposed controller can be successfully used to fix the problem of the voltage drop caused by the sudden and simultaneous charging of EVs.
Two‐stage EMS for distribution network under defensive islanding
Authors: Hu Xiaotong , Liu Tianqi , Ma Yiwei , Su Yu , Yin He , Zhu Lin , Wang Fei , Tolbert Leon M. , Liu Yilu
Published: June 2019

For some distribution networks equipped with smart switches such as Chattanooga Electric Power Board (EPB) system, they can island some areas of the network to mitigate the impact through defensive islanding. However, due to intermittency and uncertainty of renewable‐based distributed energy resources (DERs), it is highly likely that the islanded areas would experience insufficient or surplus power. This problem can be relieved by changing the boundaries of islanded areas to incorporate neighbouring load sections (LSs) or disconnect some connected LSs. Considering penetration level and sharply changing rate of renewable energy, it is challenging to define suitable boundaries for islanded areas in real time. Therefore, a two‐stage energy management system (EMS) is proposed in this study, which includes day‐ahead scheduling stage as well as short‐term and real‐time control stages. In the first stage, the initial switch combinations of LSs and DERs’ scheduling are obtained through a mixed integer quadratic programming, whereas the second stage is based on rule‐based power management algorithm. Finally, a model reduced from real EPB system is used for validating the proposed two‐stage EMS. The results successfully verify the effectiveness and performance of the proposed EMS for addressing the energy management of islanded areas under defensive islanding.
High‐speed distance relaying using least error squares method and testing with FPGA
Authors: Liu Shenyi , Jin Xingxing (Shane) , Gokaraju Ramakrishna (Rama)
Published: June 2019

The demand for high‐speed protective relaying in modern power grids is growing. A relay's fast and secure operation to clear faults is critical, especially for EHV/UHV transmission systems (400 kV and above). This research proposes a sub‐cycle distance relaying, which is based on the least error squares (LES) method, and with a data interface module implemented on field programmable gate array (FPGA). Taking advantage of inherent parallelism and pipelined architecture of the FPGA, the proposed relay design can support real‐time data communications. Also, the flexible and reliable feature of the LES algorithm allows the proposed relay to make a fast and secure trip decision in different scenarios. The case studies demonstrate the effectiveness of the LES‐based relay.
Compact low‐pass/band‐pass filters based on quarter‐mode substrate integrated waveguide and a connected network of CSRRs
Authors: Raoufi Taha , Ali Heidari Abbas
Published: June 2019

In this study, a compact low‐pass filter (LPF) and two compact dual‐wideband band‐pass filters (BPFs) are proposed based on a connected network of complementary split‐ring resonators (CSRRs) and open CSRRs (OCSRRs). The LPF is designed based on microstrip structure, and then the structure is changed to quarter‐mode substrate integrated waveguide for designing the dual‐band BPFs. The 3 dB cutoff frequency of the LPF is 1.84 GHz and its size is 0.094λg × 0.094λg, where λ is the guide wavelength at 3 dB cutoff frequency. The LPF has a wide stop‐band, up to 16 GHz. The first proposed dual‐wideband BPF has the centre frequencies of 3.85 and 8.03 GHz, with 3 dB fractional bandwidths of 31.69 and 13.7%, respectively. Finally, a sharper dual‐band BPF is obtained by cascading two proposed dual‐wideband BPFs and optimising them for the desirable response. The measured centre frequencies of the second dual‐band BPF are 3.65 and 7.15 GHz with 3 dB fractional bandwidths of 28.21 and 12.52%, respectively. The measurement results of the fabricated filters are in good agreement with the simulation ones. The filters are compared with similar reported filters in the literature, which confirm the compactness of the proposed filters..
Hilbert metamaterial printed antenna based on organic substrates for energy harvesting
Authors: Elwi Taha A. , Abdul Hassain Zaid Asaad , Tawfeeq Omar Almukhtar
Published: June 2019

In this study, an investigation is conducted to realise the possibility of organic materials use in radio frequency (RF) electronics for RF‐energy harvesting. Iraqi palm tree remnants mixed with nickel oxide nanoparticles hosted in polyethylene, INP substrates, is proposed for this study. Moreover, a metamaterial (MTM) antenna is printed on the created INP substrate of 0.8 mm thickness using silver nanoparticles conductive ink. The fabricated antenna performances are instigated numerically than validated experimentally in terms of S11 spectra and radiation patterns. It is found that the proposed antenna shows an ultra‐wide band matching bandwidth to cover the frequencies from 2.4 to 10 GHz with bore‐sight gain variation from 2.2 to 3.43 dBi at maximum. The antenna size is compacted to a 32 mm × 24 mm using a fractal‐shaped MTM when mounted on the INP substrate with a relative permittivity ɛr = 3.106−j0.0314 and a relative permeability µr = 1.548−j0.0907. Finally, the maximum obtained voltage from the proposed antenna is found about 2 V at 2.45 GHz and 2.5 V at 5.8 GHz, where, the corresponding measured equivalent isotropic radiated power is about 2.35 W at 2.45 GHz and 6.12 W at 5.8 GHz.
Radiation from free space TEM transmission lines
Authors: Ianconescu Reuven , Vulfin Vladimir
Published: June 2019

This work derives exact expressions for the radiation from two conductors non‐isolated transverse electromagnetic (TEM) transmission lines of any small electric size cross‐section in free space. The cases of infinite, semi infinite and finite transmission lines are covered and it is shown that while an infinite transmission line does not radiate, there is a smooth transition between the radiation from a finite to a semi‐infinite transmission line. The present analysis is in the frequency domain and the authors consider transmission lines carrying any combination of forward and backward waves. The analytic results are validated by successful comparison with ANSYS commercial software simulation results, and successful comparisons with other published results.
Switch fault diagnosis for boost DC–DC converters in photovoltaic MPPT systems by using high‐gain observers
Authors: Espinoza Trejo Diego R. , Taheri Shamsodin , Pecina Sánchez José A.
Published: June 2019

Open‐ and short‐circuit faults (OSCFs) in boost dc–dc converters for photovoltaic (PV) maximum power point trackers (MPPTs) imply an inefficiency after fault is triggered, which affect the security and profitability of PV projects. Hence, fault detection and isolation (FDI) techniques have become an important issue for PV technology. In this study, a model‐based FDI technique is proposed to boost dc–dc converters in PV MPPT systems. As is well‐known, major issues of model‐based FDI techniques have always been parametric uncertainty and no‐modelled dynamics. This study focuses on how to mitigate these shortcomings by applying a high‐gain observer (HGO) as a residual generator. A striking feature of HGO's is that exponential stability is still guaranteed for bounded disturbances (or faults). As demonstrated in this study, under an integral control action in the closed‐loop control system, OSCFs are characterised for ever‐growing signals, enabling the suggested FDI scheme. Also, the FDI proposal is decoupled from PV current (irradiance changes) and load variations, thereby avoiding false alarms. Moreover, the output‐injection gain and thresholds are selected such that the fault diagnosis is achieved in eight switching cycles, enabling a fast and reliable diagnosis. Experimental results are illustrated to validate the FDI scheme proposed in this study.
Design and application of electrical power backup and battery charge with a new voltage controller approach for military vehicles
Authors: Aktas Ahmet
Published: June 2019

Thanks to the increased reliability and performance of power electronics, their use in military areas is very common. Through the developing technology, military land vehicles can have many equipment rather than just a replenishment and military transport duty. For safety and confidentiality, it is not possible to supply the energy of these equipments with the 28 V lead‐acid batteries on the military vehicle during the silent watch (when the vehicle is stationary). In this study, electrical power backup and battery charge circuit has been designed and applied for military land vehicles for this purpose. When providing power to devices and charging the battery in the vehicle, it is important to ensure that the circuit is stable, robust and accordance with military standards. The output voltage of this power circuit is controlled by the use of robust control and nonlinear voltage control methods and this method brings innovation in this field. In this study, voltage surges in power circuit output due to sudden load changes are minimized by the proposed voltage control method. Thus, the conformity of the power circuit to the MIL‐STD‐1275‐E voltage surges standard, which is one of the military standards, is provided by experimental results.
Distributed power flow control using cascaded multilevel isolated bidirectional DC–DC converter with multi‐phase shift modulation
Authors: Karthikeyan V. , Gupta Rajesh
Published: June 2019

This study proposes a cascaded multilevel isolated bidirectional DC–DC converter (CMIBDC) suitable for large capacity energy storage applications. Compared to conventional IBDC, the proposed converter has higher power‐handling capacity distributed among multiple cascaded HV and LV bridges. The HV bridges are cascaded through a high‐frequency transformer with a common DC bus. On the other hand, the LV bridges are directly cascaded with isolated DC storage batteries. Effectively, the CMIBDC requires only a single DC input to store the energy in multiple battery units. A multi‐phase shift (MPS) modulation scheme has been introduced which provide wide range of power flow control. The MPS modulation shapes the high‐frequency link AC current with low THD thus reducing high‐frequency losses. Detailed operating waveforms of the proposed CMIBDC converter in different modes are presented. The performance of the proposed converter and modulation scheme has been demonstrated through PSCAD/EMTDC simulation and validated experimentally using Spartan 3AN FPGA processor‐controlled CMIBDC.
Single‐phase hybrid discontinuous conduction mode SEPIC rectifiers integrated with ladder‐type switched‐capacitor cells
Authors: Kremes William de J. , Costa Paulo J.S. , Illa Font Carlos H. , Lazzarin Telles B.
Published: June 2019

In this study, a set of new single‐phase pulse‐width modulation (PWM) Single‐ended primary‐inductor converter (SEPIC) rectifiers are proposed, which integrates conventional SEPIC rectifier, three‐state switch (TSS) and switched‐capacitor (SC) concepts. A conventional ladder‐type SC cell is modified so that it can be integrated with the SEPIC rectifier operating in discontinuous conduction mode. The set of new single‐phase PWM SEPIC rectifiers are able to provide: (i) lower‐voltage stress on the semiconductors; (ii) higher‐output voltage; and (iii) a split‐capacitor output voltage. The structure employs a TSS and three different implementations are proposed. Two of them are bridgeless versions, which can provide higher efficiencies. Hence, the proposed structures can support using the SEPIC rectifiers as step‐up in many applications and thus it can broaden its field of use. The topologies and their topological states, a theoretical steady‐state analysis, a theoretical analysis of the ladder‐type SC cell integrated with the SEPIC rectifier, a dynamic model for the control and a design example are discussed herein. Furthermore, a 500 W prototype with a 220 V input voltage, two 200 V split‐output voltages, 400 V total output voltage and 50 kHz switching frequency was designed to corroborate the theoretical study.
Design and implementation of an optimal switching controller for uninterruptible power supply inverters using adaptive dynamic programming
Authors: Gogani Khiabani Ataollah , Heydari Ali
Published: June 2019

In this study, a new approach based on adaptive dynamic programming (ADP) is proposed to control single‐phase uninterruptible power supply inverters. The control scheme uses a single function approximator, called critic, to evaluate the optimal cost and determine the optimal switching. After offline training of the critic, which is a function of system states and elapsed time, the resulting optimal weights are used in online control, to get a smooth output AC voltage in a feedback form. Simulations show the desirable performance of this controller with linear and non‐linear loads and its relative robustness to parameter uncertainty and disturbances. Furthermore, the proposed controller is upgraded so that the inverter is suitable for single‐phase variable frequency drives. Finally, as one of the few studies in the field of ADP, the proposed controllers are implemented on a physical prototype to show the performance in practise.
Islanded distributed generation system with feedforward PR‐EFLL control for AC‐electric vehicle charger
Authors: Singh Bhim , Kewat Seema , Verma Anjeet
Published: June 2019

This study deals with the islanded distributed generation system (IDGS), which is used to feed different types of loads such as AC‐EVs (electric vehicles) and non‐linear home load. The IDGS consists of solar photovoltaic (PV) array with a storage battery. In IDGS feeding, the EVs and non‐linear load, the currents contain high harmonics. Due to which, the generation of sinusoidal voltage with good quality at common coupling point (CCP) is very challenging. Therefore, a feedforward proportional resonant (PR) controller is proposed with enhanced frequency locked loop (EFLL) control algorithm to eliminate the CCP voltage harmonics and provides the high tracking capability of AC voltage as compared to the conventional proportional integral (PI) control. As a result, the voltage source converter control generates the balanced and sinusoidal CCP voltages even at unbalanced load condition. The proposed EFLL‐based control algorithm is capable to reject the DC‐offset component from the load current. Moreover, the DC‐link voltage regulation and peak power extraction of solar‐PV array are achieved through bidirectional DC–DC converter control. This BDC control is used to balance the active power flow in the islanded system. The effectiveness of the proposed IDGS is validated, through simulation as well as experimental steady‐state and dynamic test results.
Forced oscillation source location in power systems using system dissipating energy
Authors: Jha Rajiv , Senroy Nilanjan
Published: June 2019

A dissipating energy‐based technique is proposed to locate the source of forced oscillations (FOs) in power systems. The network and load information is incorporated into the developed algorithm and continuously updated using supervisory control and data acquisition (SCADA) measurement. The effect of electromechanical damping on system response in FO scenario is discussed; and therefore, the efficiency of the proposed technique to locate the source has been investigated. The proposed methodology is tested and verified for different simulation test cases and for different scenario viz. for single and multiple sources of disturbances. In the case of multiple sources of disturbances with different time of initiation of the disturbance, the proposed technique successfully locates all sources in their time durations of disturbance. Different load models have been evaluated for their impact on the success of the proposed algorithm in a real‐time digital simulation environment. The proposed technique is successfully verified for the test cases reported by the IEEE PES Task Force on Oscillation Source Location.
Transient feasibility assessment and enhancement of resilience‐oriented distribution grid restoration using parallel simulations
Authors: Chen Ying , Zhang Lu , Song Yankan , Gao Haixiang
Published: June 2019

In recent years, major power outages caused by extreme natural disasters have incurred large economic losses in distribution systems. This study proposes a transient simulation and verification method for resilience‐enhancement strategies and proposed a graphics processing unit‐based parallel simulation method. The proposed method can be used to verify the transient feasibility of the distribution system before a strategy is actually executed. Simulations are performed to verify the proposed method.
Research on local voltage control strategy based on high‐penetration distributed PV systems
Authors: Huang Xiaojian , Liu Haoming , Zhang Bo , Wang Jianchun , Xu Xiaochun
Published: June 2019

With the high‐penetration distributed photovoltaic (PV) systems accessed to a distribution network, the peak active power output of PV systems is always greater than the total local load demands, which might lead to the issues of overvoltage and reverse power flow in a distribution system. In this paper, based on the reactive power output capability of distributed PV inverters, a distributed PV reactive power local control strategy is proposed. Three types of voltage reactive power local control modes of PV inverter are analysed, respectively; they are voltage‐var control mode (Q(V) mode), adjustable power factor mode (PF(P) mode) and active power curtailment mode (APC mode). The applicable conditions of different control modes are analysed. A simulation example based on IEEE 33‐node system is studied, where the method of determining the optimal control mode under different operating scenarios of distribution system with PV is given, and the validity of the three local control modes is verified.
Operation and transient performance of a four‐terminal MMC based DC grid implementing high power mechanical DC circuit breaker
Authors: Ni Binye , Xiang Wang , Yuan Zhao , Chen Xia , Wen Jinyu
Published: June 2019

Recently, there has been significant interest in developing the modular multilevel converter (MMC) based DC grids in the power industry. However, the immature DC circuit breaker (DCCB) technology hampers the development of DC grids in overhead lines transmission field. The full controlled power electronic devices based hybrid DCCB has been proposed and researched substantially. But the hybrid type DCCB suffers from the drawback of high cost and low reliability, leading to high capital cost for DC grids that require numerous DCCBs. In this paper, a mechanical type DCCB, consisting of a mechanical switch, a circuit and an oscillation circuit, is proposed. Then, a four‐terminal bipolar MMC‐HVDC system implementing the mechanical DCCBs is studied. Extensive simulations have been conducted to analyse the transient performance under different fault conditions. The simulation results verify the technical feasibility of this mechanical DCCB in DC grid.
Two‐stage stochastic programming for the joint dispatch of energy and reserve considering demand response
Authors: Zhang Menglin , Ai Xiaomeng , Fang Jiakun , Wen Jinyu
Published: June 2019

This paper formulates a two‐stage stochastic programming model for energy and reserve joint dispatch considering wind power uncertainty and the participation of incentive‐based demand response (IBDR). The model consists two stages, the first stage is to determine the day‐ahead energy dispatch and the reserve capacity need, the second stage is to determine the deployment of reserves to accommodate the realisation of wind power uncertainty in real time. The IBDR program and the thermal power units provide reserve together to cope with the uncertainty of wind power. The IBDR model considers the maximum response times of a DR agent during a day to assure the reliability of using electricity for end users. To reduce the computation burden caused by wind power scenarios, the inactive constraints identification method is utilised to eliminate redundant transmission line constraints before solving the original model. Finally, the effectiveness of the proposed model and the solving method are tested on the modified IEEE 118‐bus test system with 50 DR agents.
Droop control method in power converter system for balancing state‐of‐charge of energy storage units in EV
Authors: Jangir Priyanka , Sangwan Venu , Kumar Rajesh , Rathore Akshay Kumar
Published: June 2019

A proficient power management between proposed multiple battery units in an EV is entailed to achieve the prolonged lifespan of batteries and to impede these from overcharging and overburdening during operation. At first, system configuration with three batteries has been developed for BEV architecture. Based on availability of their state‐of‐charge (SoC), power‐sharing among these battery units is realised by applying a droop control method on power converter system (PCS), which acts as interfacing between battery units and powertrain of EV. To get optimal use of these supplies, balancing of SoCs among these parallel modules is performed by gradual equalisation of power using droop control. Droop control is implemented for both charging and discharging modes of operation using a bi‐directional converter. SoC‐based droop control method is performed on MATLAB/Simulink model included three energy storage units (ESUs) with PCS and simulation results at the constant speed of EV are shown to demonstrate and verify the approach.
Optimal sizing and location of vanadium redox flow battery in a power system with high wind power generation
Authors: Martinez Maximiliano , Molina Marcelo Gustavo , Mercado Pedro Enrique
Published: June 2019

This paper proposes a new approach to determine the optimal sizing and location of a vanadium redox flow battery (VRFB) that provides load frequency control services in a power system, with the lowest cost for the utility grid. To this aim, the optimization model takes into account the impact of the energy storage system on the electrical system. With a stochastic optimization, the developed methodology calculates the operating costs of the electricity grid and the investment costs of the VRFB. The methodology uses a primary‐dual interior point algorithm integrated in a meta heuristic algorithm and nested in an exhaustive search method.
Multifunctional applications of batteries within fast‐charging stations based on EV demand‐prediction of the users’ behaviour
Authors: Gjelaj Marjan , Arias Nataly Bañol , Traeholt Chresten , Hashemi Seyedmostafa
Published: June 2019

This study presents a methodology to improve the operation of the power system and to deal with technical issues caused by electric vehicles (EVs) fast charging load. Fast charging stations (FCSs) are indispensable for widespread use of EVs since they can fully charge EVs in a short period of time. The integration of battery energy storage (BES) within the FCSs is considered a smart option to avoid the power congestion during the peak hours as well as the grid reinforcement costs due to FCSs. In addition, the BES can be used as multifunctional equipment, which is able to provide services such as peak shaving and frequency regulation. This study proposes a method to determine an optimal size of BES considering a stochastic modelling approach of the EVs load demand based on the users’ behaviour and their probabilistic driving patterns. Finally, a case study is carried out using a real DC fast‐charging infrastructure in Copenhagen.
Prediction of wind turbine generator bearing failure through analysis of high‐frequency vibration data and the application of support vector machine algorithms
Authors: Turnbull Alan , Carroll James , Koukoura Sofia , McDonald Alasdair
Published: June 2019

Innovations which help facilitate predictive maintenance strategies have the potential to greatly reduce costs associated with wind turbine O&M by driving efficiency and increasing wind turbine availability. This study uses multiple examples of the same generator bearing failure to provide insight into how condition monitoring systems can be used in to train machine learning algorithms with the ultimate goal of predicting failure and remaining useful life. Results show that by analysing high‐frequency vibration data and extracting key features to train support vector machine algorithms, an accuracy of 67% can be achieved in successfully predicting failure 1–2 months before occurrence. This study reflects on the limitations surrounding a generalised training approach, taking advantage of all available data, showing that if too many different examples are considered of different wind turbines and operating conditions, the overall accuracy can be diminished.
Alarms‐related wind turbine fault detection based on kernel support vector machines
Authors: Wu Yueqi , Ma Xiandong
Published: June 2019

Wind power is playing an increasingly significant role in daily life. However, wind farms are usually far away from cities especially for offshore wind farms, which brought inconvenience for maintenance. Two conventional maintenance strategies, namely corrective maintenance and preventive maintenance, cannot provide condition‐based maintenance to identify potential anomalies and predicts turbines' future operation trend. In this study, a model based data‐driven condition monitoring method is proposed for fault detection of the wind turbines (WTs) with SCADA data acquired from an operational wind farm. Due to the nature of the alarm signals, the alarm data can be used as an intermedium to link the normal data and fault data. First, KPCA is employed to select principal components (PCs) to retain the dominant information from the original dataset to reduce the computation load for further modelling. Then the selected PCs are processed for normal‐abnormal condition classification to extract those abnormal condition data that are classified further into false alarms and true alarms related to the faults. This two‐stage classification approach is implemented based on the KSVM algorithm. The results demonstrate that the two‐stage fault detection method can identify the normal, alarm and fault conditions of the WTs accurately and effectively.
SCADA based nonparametric models for condition monitoring of a wind turbine
Authors: Pandit Ravi Kumar , Infield David
Published: June 2019

High operation and maintenance costs for offshore wind turbines push up the LCOE of offshore wind energy. Unscheduled maintenance due to unanticipated failures is the most prominent driver of the maintenance cost which reinforces the drive towards condition‐based maintenance. SCADA based condition monitoring is a cost‐effective approach where power curve used to assess the performance of a wind turbine. Such power curves are useful in identification of wind turbine abnormal behaviour. IEC standard 61400‐12‐1 outlines the guidelines for power curve modelling based on binning. However, establishing such a power curve takes considerable time and is far too slow to reflect changes in performance to be used directly for condition monitoring. To address this, data‐driven, nonparametric models being used instead. Gaussian Process models and regression trees are commonly used nonlinear, nonparametric models useful in forecasting and prediction applications. In this paper, two nonparametric methods are proposed for power curve modelling. The Gaussian Process treated as the benchmark model, and a comparative analysis was undertaken using a Regression tree model; the advantages and limitations of each model will be outlined. The performance of these regression models is validated using readily available SCADA datasets from a healthy wind turbine operating under normal conditions.
Joint generation and voyage scheduling for photovoltaic integrated all‐electric ships
Authors: Fang Sidun , Cheng Haozhong , Zhang Chengming
Published: June 2019

with the onboard diesel generators and energy storage system to meet the propulsion and service load, the all‐electric ship (AES) can be viewed as a ‘mobile microgrid’. Nowadays, photovoltaic (PV) generation is gradually integrated into the AES for a ‘greener’ voyage. To fully utilise the PV energy, this paper proposes a joint generation and voyage scheduling method for the PV integrated AES. The overall model is formulated as a bi‐level programming problem and solved by column‐and‐constraint generation method. The simulation results manifest that, the integration of PV into AES leads to reductions on both the fuel consumption and CO2 emission.
Voltage source control of offshore all‐DC wind farm
Authors: Yang Renxin , Shi Gang , Cai Xu , Zhang Xiaoping
Published: June 2019

The fast growth of offshore all‐DC wind farm will bring problems such as the weakening of grid frequency stability and the increase of equivalent grid impedance. To overcome this, a coordination control strategy for offshore all‐DC wind farm is proposed in this study with two salient features: better performance under weak grid condition, and real‐time frequency support from wind farm. This strategy consists of three parts: the inertia synchronising control of receiving end converter, the constant ratio control of DC transformer and the frequency response of wind farm. With the proposed strategy, the all‐DC wind farm operates like a synchronous generator to onshore grid, which provides fast frequency support when the onshore grid frequency changes. The effectiveness of the proposed method is validated in PSCAD/EMTDC.
Constraints on positron annihilation kinematics in the inner Galaxy
Authors: Siegert Thomas , Crocker Roland M. , Diehl Roland , Krause Martin G. H. , Panther Fiona H. , Pleintinger Moritz M. M. , Weinberger Christoph
Published: June 2019

Context. The annihilation of cosmic positrons with electrons in the interstellar medium results in the strongest persistent γ-ray line signal in the sky. For the past 50 yr, this 511 keV emission – predominantly from the galactic bulge region and from a low surface-brightness disk – has puzzled observers and theoreticians. A key issue for understanding positron astrophysics is found in cosmic-ray propagation, especially at low kinetic energies (≲10 MeV).

Aims. We want to shed light on how positrons propagate and the resulting morphology of the annihilation emission. We approach this “positron puzzle” by inferring kinematic information of the 511 keV line in the inner radian of the Galaxy. This constrains propagation scenarios and positron source populations in the Milky Way.

Methods. By dissecting the positron annihilation emission as measured with INTEGRAL/SPI, we derived spectra for individual and independent regions in the sky. The centroid energies of these spectra around the 511 keV line are converted into Doppler shifts, representing the line-of-sight velocity along different galactic longitudes. This results in a longitude-velocity diagram of positron annihilation. From high-resolution spectra, we also determined Doppler-broadening from γ-ray line shape parameters to study annihilation conditions as they vary with galactic longitude.

Results. We found line-of-sight velocities in the 511 keV line that are consistent with zero, as well as with galactic rotation from CO measurements (2–3 km s−1 deg−1), and measurements of radioactive 26Al (7.5–9.5 km s−1 deg−1). The velocity gradient in the inner ±30° is determined to be 4 ± 6 km s−1 deg−1. The width of the 511 keV line is constant as a function of longitude at 2.43 ± 0.14 keV, with possibly different values towards the disk. The positronium fraction is found to be 1.0 along the galactic plane.

Conclusions. The weak signals in the disk leave the question open of whether positron annihilation is associated with the high velocities seen in 26Al or rather with ordinarily rotating components of the Milky Way’s interstellar medium. We confirm previous results that positrons are slowed down to the 10 eV energy scale before annihilation and constrain bulk Doppler-broadening contributions to ≲1.25 keV in the inner radian. Consequently, the true annihilation conditions remain unclear.