bluuebunny/crossref_metadata_2025 huggingface dataset:
Synergic effect of adsorbed gas and charging on surface flashover
Authors: Li Shengtao , Huang Yin , Min Daomin , Qu Guanghao , Niu Huan , Li Zhen , Wang Weiwang , Li Jianying , Liu Wenfeng
Published: April 2019

Flashover is a crucial issue in both high-voltage engineering and surface physics. It not only challenges the existing theories about its dynamic evolution, but also inhibits the clean energy revolution by limiting the accessible voltage rating of power equipment. It is of significance to elucidate the microscopic process along the interface to improve the flashover performance. In the present study, the synergic effect of adsorbed gas and surface charging is investigated, which reveals a long ignored factor for determining the flashover voltage. Depending on the relative amount of adsorbed gas, the flashover voltage varies, which exhibit different behavior from the bulk breakdown of the same gas. The amount of N2 gas adsorbed on epoxy resin (EP) surface is much larger than that on Al2O3 ceramic surface, corresponding to the observed higher flashover voltage on EP. It is proposed that the adsorbed gas molecules not only modify the local surface charging state via their interaction with the trapped charges, but also capture free electrons due to the distortion of their electronic distribution. Both effects suppress the free path length of electrons in the gas-solid interface. This work explores another possibility to improve the surface flashover performance.
New marking method involving a light-emitting diode and power source device to localize gastrointestinal cancer in laparoscopic surgery
Authors: Wada Yuma , Miyoshi Norikatsu , Fujino Shiki , Ohue Masayuki , Yasui Masayoshi , Takahashi Yusuke , Takahashi Hidekazu , Nishimura Junichi , Takenaka Yuya , Saso Kazuhiro , Tomokuni Akira , Sugimura Keijiro , Akita Hirofumi , Takahashi Hidenori , Kobayashi Shogo , Omori Takeshi , Miyata Hiroshi , Yano Masahiko
Published: April 2019

Although the preoperative endoscopic marking method using dye is widely used, the dye can spread into the tissue or abdominal cavity, inducing the inflammation and leading to the wrong dissection. We developed a novel marking method using an endoscopic clip with a light emitting diode (LED) and a power source device to detect the accurate location of the site of interest. We performed this new marking method in three patients with gastrointestinal cancers. We placed an endoscopic clip with an LED on the gastrointestinal mucosa and used a power source device outside of the human body to detect the LED. We detected the clip with the LED using the power source device. We also confirmed the usefulness of this clip in three of three (100%) patients with colorectal and gastric cancer. We developed a novel marking device using an LED to identify an objective location successfully.
A plasma protein derived TGFβ signature is a prognostic indicator in triple negative breast cancer
Authors: Katayama Hiroyuki , Tsou Peiling , Kobayashi Makoto , Capello Michela , Wang Hong , Esteva Francisco , Disis Mary L. , Hanash Samir
Published: April 2019

We investigated the potential of in-depth quantitative plasma proteome analysis to uncover proteins predictive of progression and metastasis in triple negative breast cancer (TNBC). Analysis of samples from 24 pre-menopausal and 24 post-menopausal women with newly diagnosed TNBC who subsequently developed metastasis or remained metastasis free were utilized in the proteomic discovery set, which resulted in 43 proteins associated with tumor progression. These proteins were found to form a hierarchical network with TGFβ. The signature was further confirmed and refined by integrating plasma protein data from a murine TNBC model that encompassed mice with rapid- versus slow-growing tumors. Three genes consisting of CLIC1, MAPRE1, and SERPINA3 in the refined TGFβ signature significantly stratified overall survival (log-rank p = 0.0141) in a larger validation cohort irrespective of menopausal status, tumor stage, grade, and size.
Chemical fixation of carbon dioxide catalyzed via cobalt (III) ONO pincer ligated complexes
Authors: Ullah Habib , Mousavi Bibimaryam , Younus Hussein A. , Khattak Zafar A. K. , Chaemchuen Somboon , Suleman Suleman , Verpoort Francis
Published: April 2019

Chemical insertion of carbon dioxide into epoxides under ambient conditions has become one of the most important methods for the construction of cyclic organic carbonates. Various active salen, salophen, and phenolate ligand based complexes have been reported for the synthesis of cyclic organic carbonates. Here we demonstrate a series of ONO pincer type cobalt (III) complexes as efficient catalysts for the cycloaddition of carbon dioxide to epoxides in neat conditions at atmospheric pressure with and without co-catalyst. A turnover number of up to 200,000 under atmospheric pressure is achieved. Moreover, the in situ generated complex shows high activity and the catalyst can be reused for at least 11 cycles without any decline in catalytic performance.
First-principles prediction of phonon-mediated superconductivity in XBC (X = Mg, Ca, Sr, Ba)
Authors: Haque Enamul , Hossain M. Anwar , Stampfl Catherine
Published: April 2019

The calculated superconducting critical temperature (Tc) of MgBC is 51 K; notably, higher than that of MgB2.
One catalyst, multiple processes: ligand effects on chemoselective control in Ru-catalyzed anti-Markovnikov reductive hydration of terminal alkynes
Authors: Ye Zongren , Huang Xiao , Shao Youxiang , Jiang Jingxing , Qu Ling-Bo , Zhao Cunyuan , Ke Zhuofeng
Published: April 2019

The ligand effect through kinetic and thermodynamic control on the chemoselectivity of one-catalyst multi-step catalysis.
Transcriptomic response of the benthic freshwater diatomNitzschia paleaexposed to Few Layer Graphene
Authors: Garacci Marion , Barret Maialen , Folgoas Clément , Flahaut Emmanuel , Chimowa George , Bertucci Anthony , Gonzalez Patrice , Silvestre Jérôme , Gauthier Laury , Zouine Mohamed , Pinelli Eric
Published: April 2019

FLG induces strong physiological modifications as a survival strategy ofNitzschia palea, at cell and biofilm scale.
Stereoselective synthesis of spirocyclohexadiene-pyrazolones via organic base and/or hydrogen bonding assisted [3 + 3] annulation reactions
Authors: Sun Bing-Bing , Zhang Jun-Qi , Chen Jun-Bo , Fan Wei-Tai , Yu Jie-Qiang , Hu Jia-Ming , Wang Xing-Wang
Published: April 2019

A DABCO and a chiral hydrogen bonding-assisted catalyzed [3 + 3] cycloaddition of α-arylidene pyrazolinones and 2-benzylidenemalononitriles provided spirocyclohexadiene-pyrazolones with all-carbon quaternary centers in good yields with excellent ees and moderate to high drs.
Influence of surface tension-driven network parameters on backflow strength
Authors: Lee Yonghun , Seder Islam , Kim Sung-Jin
Published: April 2019

This paper analyzes the effect of device elements on backflow of a surface tension-driven microfluidic device.
A review of stability-enhanced luminescent materials: fabrication and optoelectronic applications
Authors: Liu Jiahui , Yang Zunxian , Ye Bingqing , Zhao Zhiwei , Ruan Yushuai , Guo Tailiang , Yu Xuebin , Chen Gengxu , Xu Sheng
Published: April 2019

This review mainly focuses on the recent important work on stability-enhanced strategies of luminescent materials. Various strategies on the fabrications have been summarized and corresponding optoelectronic applications are presented.
Insight into the internal structure of amyloid-β oligomers by isotope-edited Fourier transform infrared spectroscopy
Authors: Baronio Cesare M. , Baldassarre Maurizio , Barth Andreas
Published: April 2019

Isotope-edited infrared spectroscopy reveals the structural unit of amyloid-β oligomers.
Multitribe evolutionary search for stable Cu–Pd–Ag nanoparticles using neural network models
Authors: Hajinazar Samad , Sandoval Ernesto D. , Cullo Aiden J. , Kolmogorov Aleksey N.
Published: April 2019

We present an approach based on two bio-inspired algorithms to accelerate the identification of nanoparticle ground states.
Ethanol condensation at elevated pressure over copper on AlMgO and AlCaO porous mixed-oxide supports
Authors: Petrolini Davi D. , Eagan Nathaniel , Ball Madelyn R. , Burt Samuel P. , Hermans Ive , Huber George W. , Dumesic James A. , Martins Leandro
Published: April 2019

The coupling of ethanol to produce C4-compounds by Guerbet condensation at 325 °C was studied using porous mixed oxide catalysts of AlMgO and AlCaO prepared by the emulsion mediated method with and without the addition of Cu.
Fe in biosynthesis, translocation, and signal transduction of NO: toward bioinorganic engineering of dinitrosyl iron complexes into NO-delivery scaffolds for tissue engineering
Authors: Hsiao Hui-Yi , Chung Chieh-Wei , Santos Joshua H. , Villaflores Oliver B. , Lu Tsai-Te
Published: April 2019

The ubiquitous physiology of nitric oxide enables the bioinorganic engineering of [Fe(NO)2]-containing and NO-delivery scaffolds for tissue engineering.
A tris-(manganese(iii))corrole–porphyrin–corrole triad: synthesis, characterization and catalytic epoxidation
Authors: Rai Jyoti , Basumatary Biju , Bhandary Subhrajyoti , Murugavel Muthuchamy , Sankar Jeyaraman
Published: April 2019

A homotrimetallic manganese(iii) corrole–porphyrin–corrole triad has been synthesized and structurally characterized.
A 3,4-dimercapto-3-cyclobutene-1,2-dione-chelated ruthenium carbene catalyst for Z-stereoretentive/stereoselective olefin metathesis
Authors: Wang Tao , Xie Qingxiao , Guo Weijie , Wu Shutao , Zhang Huiqing , Wang Jianhui , Wu Botao
Published: April 2019

A ruthenium carbene catalyst chelated with a 3,4-dioxocyclobut-1-ene-1,2-dithiolate ligand was synthesized and its molecular structure was determined by single-crystal X-ray diffraction.
Endoplasmic reticulum targeted cyclometalated iridium(iii) complexes as efficient photodynamic therapy photosensitizers
Authors: Yuan Bo , Liu Jiangping , Guan Ruilin , Jin Chengzhi , Ji Liangnian , Chao Hui
Published: April 2019

A series of ER-targeted cyclometalated Ir(iii) complexes with a gradually extended conjugated area in the main ligand were effective PDT photosensitizers and triggered ER-stress induced apoptosis in cancer cell lines.
Nanoparticle foam flotation for caesium decontamination using a pH-sensitive surfactant
Authors: Micheau Cyril , Dedovets Dmytro , Bauduin Pierre , Diat Olivier , Girard Luc
Published: April 2019

A fine tuning of the electrostatic interactions between Cu-Prussian blue analog nanoparticles and a pH responsive surfactant for an efficient and low-footprint caesium extraction process.
On-surface trapping of alkali atoms by crown ethers in ultra high vacuum
Authors: Stredansky Matus , Turco Elia , Feng Zhijing , Costantini Roberto , Comelli Giovanni , Verdini Alberto , Floreano Luca , Morgante Alberto , Dri Carlo , Cossaro Albano
Published: April 2019

Crown ethers of a hetero-organic architecture in ultra-high vacuum are the preferential trapping sites for Na atoms.
Turn-on fluorescent sensor for the detection of lipopolysaccharides based on a novel bispyrenyl terephtalaldehyde-bis-guanylhydrazone
Authors: Khownium Kriangsak , Romsaiyud Jariya , Borwornpinyo Suparerk , Wongkrasant Preedajit , Pongkorpsakol Pawin , Muanprasat Chatchai , Boekfa Bundet , Vilaivan Tirayut , Ruchirawat Somsak , Limtrakul Jumras
Published: April 2019

A “turn-on” bispyrenyl sensor for lipopolysaccharide detection with unique molecular conformations exhibits excimer emission with sensitivity down to nanomolar.
Thiolation of NHC-boranes: influence of the substitution at boron
Authors: Vallet Anne-Laure , Lacôte Emmanuel
Published: April 2019

B-Substituted NHC-boranes react with aryldisulfides to generate mono-thiolated compounds selectively under both ionic or radical conditions.
Arginine mimetic appended peptide-based probes for fluorescence turn-on detection of 14-3-3 proteins
Authors: Maity Debabrata , Gigante Alba , Sánchez-Murcia Pedro A. , Sijbesma Eline , Li Mao , Bier David , Mosel Stefanie , Knauer Shirley , Ottmann Christian , Schmuck Carsten
Published: April 2019

Development of fluorescence markers for the 14-3-3 adapter protein class.
Recent insights into near-infrared light-responsive carbon dots for bioimaging and cancer phototherapy
Authors: Zhou Bo , Guo Zhengxi , Lin Zhaoxing , Zhang Lizheng , Jiang Bang-Ping , Shen Xing-Can
Published: April 2019

The current developments of NIR-responsive CDs and their applications in bioimaging and phototherapy are highlighted in this review.
The odd–even effect of alkyl chain in organic room temperature phosphorescence luminogens and the corresponding in vivo imaging
Authors: Yang Jie , Gao Heqi , Wang Yunsheng , Yu Yun , Gong Yanbin , Fang Manman , Ding Dan , Hu Wenping , Tang Ben Zhong , Li Zhen
Published: April 2019

Six alkyl substituted phenothiazine 5,5-dioxide derivatives, containing groups from methyl to hexyl groups, were synthesized, and demonstrated an apparent odd–even effect in RTP lifetime never observed before.
A stabilized lamellar liquid crystalline phase with aggregation-induced emission features based on pyrrolopyrrole derivatives
Authors: Dai Shuangxiong , Cai Zhengxu , Peng Zhe , Wang Zhi , Tong Bin , Shi Jianbing , Gan Shenglong , He Qiming , Chen Wei , Dong Yuping
Published: April 2019

A series of novel AIE-active liquid crystals were prepared, which exhibited stabilized and well-organized lamellar structures in the LC phase.
The solvent effect on the excited-state intramolecular proton transfer of cyanine derivative molecules
Authors: Shi Wei , Yang Yunfan , Zhao Yu , Li Yongqing
Published: April 2019

Essential comprehension of the ESIPT mechanism in different solvents is helpful to design excellent fluorescent probes for lysosome organelles.
Carboxylate phosphabetaine as a bifunctional organocatalyst for the intramolecular ring opening of oxetane
Authors: Xu Dongyang , Wei Hongbo , Zhen Yanxia , Gao Yu-Qi , Li Ruoxin , Li Xingzhou , He Yupeng , Zhang Zhong , Xie Weiqing
Published: April 2019

Carboxylate phosphabetaine acts as a competent organocatalyst for promoting the intramolecular ring opening of oxetanes.
Visible-light-induced oxidative ring expansion of indoles with amidines
Authors: Zhang Ling-Ling , Cao Wen-Bin , Xu Xiao-Ping , Ji Shun-Jun
Published: April 2019

An efficient and mild visible-light-enabled reaction involving the oxidative ring expansion of indoles with amidines in the aqueous phase at room temperature is developed.
Highly efficient reduction of 4-nitrophenolate to 4-aminophenolate by Au/γ-Fe2O3@HAP magnetic composites
Authors: Xia Yide , Liu Ying , Shi Nannan , Zhang Xungao
Published: April 2019

In this article, the catalyst Au/γ-Fe2O3@hydroxyapatite (Au/γ-Fe2O3@HAP) consisting of Au nanoparticles supported on the core–shell structure γ-Fe2O3@HAP was prepared through a deposition–precipitation method.
Mechanistic insight into the catalytic hydrogenation of nonactivated aldehydes with a Hantzsch ester in the presence of a series of organoboranes: NMR and DFT studies
Authors: Hamasaka Go , Tsuji Hiroaki , Ehara Masahiro , Uozumi Yasuhiro
Published: April 2019

Mechanistic studies on the organoborane-catalyzed transfer hydrogenation of nonactivated aldehydes with a Hantzsch ester as a synthetic NADPH analogue were performed by NMR experiments and DFT calculations.
The full dynamics of energy relaxation in large organic molecules: from photo-excitation to solvent heating
Authors: Balevičius Jr Vytautas , Wei Tiejun , Di Tommaso Devis , Abramavicius Darius , Hauer Jürgen , Polívka Tomas , Duffy Christopher D. P.
Published: April 2019

In some molecular systems, such as nucleobases, polyenes or sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale. Where does this energy go or among which degrees of freedom it is being distributed at such early times?
Genome mining and biosynthesis of kitacinnamycins as a STING activator
Authors: Shi Jing , Liu Cheng Li , Zhang Bo , Guo Wen Jie , Zhu Jiapeng , Chang Chin-Yuan , Zhao Er Juan , Jiao Rui Hua , Tan Ren Xiang , Ge Hui Ming
Published: April 2019

Genome mining targeting unique type II PKS and NRPS led to the identification of a novel class of glycopeptides named kitacinnamycins.
Chiral diversification through the assembly of achiral phenylacetylene macrocycles with a two-fold bridge
Authors: Katoono Ryo , Kusaka Keiichi , Saito Yuki , Sakamoto Kazuki , Suzuki Takanori
Published: April 2019

Multiple chiral molecules were generated through the assembly and double-bridging of achiral phenylacetylene macrocycles.
An ion-conducting SnS–SnS2hybrid coating for commercial activated carbons enabling their use as high performance anodes for sodium-ion batteries
Authors: Zhang Si-Wei , Lv Wei , Qiu Dong , Cao Tengfei , Zhang Jun , Lin Qiaowei , Chen Xiangrong , He Yan-Bing , Kang Feiyu , Yang Quan-Hong
Published: April 2019

An ion-conducting metal sulfide coating on activated carbon can dramatically address the bottleneck of ultra-low efficiency for sodium storage.
Fullerene as an efficient hybridization matrix for exploring high-performance layered-double-hydroxide-based electrodes
Authors: Kim Yeon Hwa , Jin Xiaoyan , Hwang Seong-Ju
Published: April 2019

The hybridization of inorganic solids with fullerene (C60) nanosheets provides an effective way to explore high-performance hybrid-type electrode materials.
Generation of edge dislocation defects in Co3O4 catalysts: an efficient tactic to improve catalytic activity for oxygen evolution
Authors: Li Xiumin , Su Xinyu , Pei Ying , Liu Jie , Zheng Xuejing , Tang Keyong , Guan Guoqing , Hao Xiaogang
Published: April 2019

A pioneering way is demonstrated to synthesize Co3O4 catalysts with abundant edge dislocation defects, which exhibit excellent OER catalytic performance.
Heterogeneous single-site synergetic catalysis for spontaneous photocatalytic overall water splitting
Authors: Su Hui , Liu Meihuan , Cheng Weiren , Zhao Xu , Hu Fengchun , Liu Qinghua
Published: April 2019

Heterogeneous Pt1Nx–Au1Nx redox single sites anchored on a g-C3N4 support were designed for high-efficiency spontaneous photocatalytic overall water splitting.
Synthesis, characterization and in vitro validation of a magnetic zeolite nanocomposite with T2-MRI properties towards theranostic applications
Authors: Vilaça Natália , Gallo Juan , Fernandes Rui , Figueiredo Francisco , Fonseca António M. , Baltazar Fátima , Neves Isabel C. , Bañobre-López Manuel
Published: April 2019

This study focusses on the development of a magnetic zeolite nanocomposite as a suitable platform towards the design of a theranostic system. Herein, we explored its ability to act as a T2-MRI contrast enhancer when magnetic nanoparticles are incorporated in its structure.
Tough hydrophilic polyurethane-based hydrogels with mechanical properties similar to human soft tissues
Authors: Oveissi Farshad , Naficy Sina , Le Thi Yen Loan , Fletcher David F. , Dehghani Fariba
Published: April 2019

Biocompatible tough hydrogels are ideal for the fabrication of flexible medical devices such as prosthetics.
Power generation from the Cu26Nb2Ge6S32-based single thermoelectric element with Au diffusion barrier
Authors: Chetty Raju , Kikuchi Yuta , Bouyrie Yohan , Jood Priyanka , Yamamoto Atsushi , Suekuni Koichiro , Ohta Michihiro
Published: April 2019

A conversion efficiency of ∼3.3% has been successfully demonstrated in colusite (Cu26Nb2Ge6S32)-based single thermoelectric element with Au diffusion barrier.
Enhanced single-mode fiber laser emission by nano-crystallization of oxyfluoride glass-ceramic cores
Authors: Kang Shiliang , Huang Zhenpeng , Lin Wei , Yang Dandan , Zhao Junjie , Qiao Xvsheng , Xiao Xiudi , Xu Shanhui , Qiu Jianrong , Du Jincheng , Dong Guoping
Published: April 2019

We have demonstrated enhanced 1.55 μm single-mode fiber laser output in KYF4:Er3+/Yb3+ nanocrystal embedded oxyfluoride glass ceramic fibers.
Gut microbiota in obstructive sleep apnea–hypopnea syndrome: disease-related dysbiosis and metabolic comorbidities
Authors: Ko Chih-Yuan , Liu Qing-Quan , Su Huan-Zhang , Zhang Hua-Ping , Fan Ji-Mim , Yang Jiao-Hong , Hu An-Ke , Liu Yu-Qi , Chou Dylan , Zeng Yi-Ming
Published: April 2019

Gut microbiota alterations manifest as intermittent hypoxia and fragmented sleep, thereby mimicking obstructive sleep apnea–hypopnea syndrome (OSAHS). Here, we sought to perform the first direct survey of gut microbial dysbiosis over a range of apnea–hypopnea indices (AHI) among patients with OSAHS. We obtained fecal samples from 93 patients with OSAHS [5 < AHI ≤ 15 (n=40), 15 < AHI ≤ 30 (n=23), and AHI ≥ 30 (n=30)] and 20 controls (AHI ≤ 5) and determined the microbiome composition via 16S rRNA pyrosequencing and bioinformatics analysis of variable regions 3–4. We measured fasting levels of homocysteine (HCY), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). Results revealed gut microbial dysbiosis in several patients with varying severities of OSAHS, reliably separating them from controls with a receiver operating characteristic-area under the curve (ROC-AUC) of 0.789. Functional analysis in the microbiomes of patients revealed alterations; additionally, decreased in short-chain fatty acid (SCFA)-producing bacteria and increased pathogens, accompanied by elevated levels of IL-6. Lactobacillus levels correlated with HCY levels. Stratification analysis revealed that the Ruminococcus enterotype posed the highest risk for patients with OSAHS. Our results show that the presence of an altered microbiome is associated with HCY among OSAHS patients. These changes in the levels of SCFA affect the levels of pathogens that play a pathophysiological role in OSAHS and related metabolic comorbidities.
Emerging CRISPR/Cas9 applications for T-cell gene editing
Authors: Preece Roland , Georgiadis Christos
Published: April 2019

Gene editing tools are being rapidly developed, accelerating many areas of cell and gene therapy research. Each successive gene editing technology promises increased efficacy, improved specificity, reduced manufacturing cost and design complexity; all of which are currently epitomised by the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein (Cas9) platform. Since its conceptualisation, CRISPR-based gene editing has been applied to existing methodologies and has further allowed the exploration of novel avenues of research. Implementation of CRISPR/Cas9 has been instrumental to recent progress in the treatment of cancer, primary immunodeficiency, and infectious diseases. To this end, T-cell therapies have attempted to harness and redirect antigen recognition function, and through gene editing, broaden T-cell targeting capabilities and enhance their potency. The purpose of this review is to provide insights into emerging applications of CRISPR/Cas9 in T-cell therapies, to briefly address concerns surrounding CRISPR-mediated indel formation, and to introduce CRISPR/Cas9 base editing technologies that hold vast potential for future research and clinical translation.
Indoor passive localisation based on reliable CSI extraction
Authors: Yu Hongli , Chen Gui‐Lin , Yu Gwo‐Jong , Zhao Sheng‐Hui , Yang Bin , Liu Jinjun
Published: April 2019

In indoor environment, passive human detection and localisation are important enabling technologies for elder healthcare, emergence rescue and target tracking applications. Recently, the fine‐grained channel state information (CSI) of Wi‐Fi was adopted for indoor localisation due to the low‐cost Wi‐Fi network interface card and available firmware modifications for CSI extraction. However, due to multipath fading and spatial‐temporal dynamics of wireless channel, stable CSI extraction is a challenging task to achieve reliable CSI fingerprint matching. In this study, the sensitivity of CSI is first analysed and stable CSI fingerprints can be obtained by reducing the variance from interference and white noise. The stable CSI fingerprints are then classified by quadratic discriminant analysis to achieve location matching. Extensive experiments have been conducted to justify the system performance. The results reveal that the proposed indoor passive localisation system outperforms passive CSI‐MIMO system in terms of performance.
Adaptive super‐twisting sliding mode control of three‐phase power rectifiers in active front end applications
Authors: Luo Wensheng , Zhao Tongyu , Li Xiaolei , Wang Zhenhuan , Wu Ligang
Published: April 2019

A robust control approach for three‐phase two‐level grid‐connected power converters using an adaptive super‐twisting algorithm (ASTA) is studied. A cascaded structure of the proposed control method is employed, which consists of two control loops, the dc‐link capacitor voltage regulation loop (outer loop) and the grid phase current tracking loop (inner loop). In the outer control loop, a proportional controller using technique is considered, which is designed to regulate the dc‐link capacitor voltage to some desired value. An extended state observer used to asymptotically estimate the external disturbance is integrated into the outer control loop. For the inner control loop, two ASTA‐based controllers are implemented that force the grid phase currents to their desired values in finite time. Lyapunov analysis is provided to show the finite time convergence of the closed‐loop system. With the help of ASTA, a priori knowledge of the upper bounds of the derivative of the disturbances is not required. Illustrative simulation results in comparison with the linear proportional–integral control method are provided to demonstrate the effectiveness and robustness of the proposed ASTA, in the presence of load variation and parametric uncertainty.
Harmonic compensation capability‐based coordinated control for hybrid wind farms under distorted grid voltage conditions
Authors: Liu Ruikuo , Yao Jun , Guo Lisha , Wang Xiongfei , Blaabjerg Frede
Published: April 2019

This article presents a harmonic compensation capability‐based coordinated control strategy for a hybrid wind farm including doubly fed induction generator (DFIG)‐based and direct‐driven permanent‐magnet synchronous generator (PMSG)‐based wind turbines operation under distorted grid voltage conditions. First, the maximum harmonic current compensation capabilities of the DFIG and PMSG systems are analysed in detail when the grid voltage is harmonically distorted. Combining the maximum harmonic current compensation capabilities with the harmonic current requirements of different control targets, the controllable operating regions of each control target of the DFIG and PMSG systems during network voltage distortions are presented. Furthermore, the effects of the voltage total harmonic distortion (THD) and the system operating conditions on the controllable operating regions are analysed. Based on the analysis, the coordination strategy is proposed for a hybrid wind farm without communication equipment between the different wind power generators. The proposed strategy can improve the interoperability and the output power quality of the entire hybrid wind farm during grid‐voltage harmonic distortions. Finally, the effectiveness of the proposed coordination strategy for the hybrid wind farm is validated by simulation and experimental results.
Modeling of CoRoT and Spitzer lightcurves in NGC 2264 caused by an optically thick warp
Authors: Nagel E. , Bouvier J.
Published: April 2019

Aims. We present an analysis of simultaneously observed CoRoT and Spitzer lightcurves for four systems in the stellar forming region NGC 2264: Mon-660, Mon-811, Mon-1140, and Mon-1308. These objects share in common a strong resemblance between the optical and infrared lightcurves, such that the mechanism responsible for producing them is the same. The aim of this paper is to explain both lightcurves simultaneously with only one mechanism.

Methods. We modeled the infrared emission as coming from a warp composed of an optically thick wall and an optically thick asymmetric disk beyond this location. We modeled the optical emission mainly by partial stellar occultation by the warp.

Results. The magnitude amplitude of the CoRoT and Spitzer observations for all the objects can be described with the emission coming from the system components. The difference between them is the value of the disk flux compared with the wall flux and the azimuthal variations of the former. This result points out the importance of the hydrodynamical interaction between the stellar magnetic field and the disk.

Conclusions. CoRoT and Spitzer lightcurves for the stellar systems Mon-660, Mon-811, Mon-1140, and Mon-1308 can be simultaneously explained using the emission coming from an asymmetric disk and emission with stellar occultation by an optically thick wall.
Destruction of dimethyl ether and methyl formate by collisions with He+
Authors: Ascenzi Daniela , Cernuto Andrea , Balucani Nadia , Tosi Paolo , Ceccarelli Cecilia , Martini Luca Matteo , Pirani Fernando
Published: April 2019

Context. To correctly model the abundances of interstellar complex organic molecules (iCOMs) in different environments, both formation and destruction routes should be appropriately accounted for. While several scenarios have been explored for the formation of iCOMs via grain and gas-phase processes, much less work has been devoted to understanding the relevant destruction pathways, with special reference to (dissociative) charge exchange or proton transfer reactions with abundant atomic and molecular ions such as He+, H3+and HCO+.

Aims. By using a combined experimental and theoretical methodology we provide new values for the rate coefficients and branching ratios (BRs) of the reactions of He+ions with two important iCOMs, namely dimethyl ether (DME) and methyl formate (MF). We also review the destruction routes of DME and MF by other two abundant ions, namely H3+and HCO+.

Methods. Based on our recent laboratory measurements of cross sections and BRs for the DME/MF + He+reactions over a wide collision energy, we extended our theoretical insights on the selectivity of the microscopic dynamics to calculate the rate coefficientsk(T) in the temperature range from 10 to 298 K. We implemented these new and revised kinetic data in a general model of cold and warm gas, simulating environments where DME and MF have been detected.

Results. Due to stereodynamical effects present at low collision energies, the rate coefficients, BRs and temperature dependences here proposed differ substantially from those reported in KIDA and UDfA, two of the most widely used astrochemical databases. These revised rates impact the predicted abundances of DME and MF, with variations up to 40% in cold gases and physical conditions similar to those present in prestellar cores.

Conclusions. This work demonstrates that the accuracy of astrochemical models can be improved by a thorough characterisation of the destruction routes of iCOMs. The details of the chemical systems can, indeed, strongly affect their efficiency and significant deviations with respect to the commonly used Langevin model estimates are possible.
Quasi-stellar objects acting as potential strong gravitational lenses in the SDSS-III BOSS survey
Authors: Meyer Romain A. , Delubac Timothée , Kneib Jean-Paul , Courbin Frédéric
Published: April 2019

We present a sample of 12 quasi-stellar objects (QSOs) that potentially act as strong gravitational lenses on background emission line galaxies (ELG) or Lyman-α emitters (LAEs) selected through a systematic search of the 297 301 QSOs in the Sloan Digital Sky Survey (SDSS)-III Data Release 12. Candidates were identified by looking for compound spectra, where emission lines at a redshift larger than that of the quasar can be identified in the residuals after a QSO spectral template is subtracted from the observed spectra. The narrow diameter of BOSS fibers (2″) then ensures that the object responsible for the additional emission lines must lie close to the line of sight of the QSO and hence provides a high probability of lensing. Among the 12 candidates identified, nine have definite evidence for the presence of a background ELG identified by at least four higher-redshift nebular emission lines. The remaining three probable candidates present a strong asymmetrical emission line attributed to a background Lyman-α emitter (LAE). The QSO-ELG (QSO-LAE) lens candidates have QSO lens redshifts in the range 0.24 ≲ zQSO ≲ 0.66 (0.75 ≲ zQSO ≲ 1.23 ) and background galaxy redshifts in the range 0.48 ≲ zS, ELG ≲ 0.94 (2.17 ≲ zS, LAE ≲ 4.48). We show that the algorithmic search is complete at > 90% for QSO-ELG systems, whereas it falls at 40−60% for QSO-LAE, depending on the redshift of the source. Upon confirmation of the lensing nature of the systems, this sample may quadruple the number of known QSOs acting as strong lenses. We have determined the completeness of our search, which allows future studies to compute lensing probabilities of galaxies by QSOs and differentiate between different QSO models. Future imaging of the full sample and lens modelling offers a unique approach to study and constrain key properties of QSOs.
Nonconservative Rayleigh scattering
Authors: Frisch H.
Published: April 2019

Context. The continuous spectrum of stellar and planetary atmospheres can be linearly polarized by Rayleigh or Thomson scattering. The polarization rate depends on the ratio κc/(κc + σc), κc and σc being the absorption coefficients due to photo-ionizations and scattering processes, respectively. The scattering process is conservative if κc = 0, and in this case the center-to-limb variation of the polarization rate follows Chandrasekhar’s law. Deviations from this law appear if the scattering is nonconservative, that is, if photons have a probability ϵ = κc/(κc + σc) of being destroyed at each scattering.

Aims. Nonconservative Rayleigh scattering is addressed here with a perturbation point of view, using ϵ, assumed to be a constant, as an expansion parameter. The goal is to obtain a perturbation expansion of the polarized radiation field that can be used to measure of the effects of a nonzero ϵ on the polarization rate of the emergent radiation and to check the accuracy of numerical codes.

Methods. The expansion method is an application to Rayleigh scattering of a general perturbation approach developed for scalar monochromatic transport equations. The introduction of a space variable, rescaled by a factor √ϵ, transforms the radiative transfer equation into a new equation from which one can extract simpler equations to describe the field in the interior of the medium and in boundary layers.

Results. The perturbation method is applied to a plane-parallel slab with no incident radiation and an unpolarized primary source of photons. The interior and boundary layer fields are expanded in powers of √ϵ. The expansion of the interior radiation field shows that it is unpolarized at leading order, with an intensity i0(τ̃) satisfying a diffusion equation, and that the polarization appears at order ϵ. The emergent radiation is calculated up to and including order ϵ. The leading term yields the polarization rate of the Chandrasekhar’s law. The following one, of order √ϵ, accurately predicts the decrease of the polarization rate for values of ϵ up to 10−3 and shows that it varies roughly as (1 − μ) for any unpolarized primary source. Methods for testing the accuracy of numerical schemes are proposed. The perturbation method is also applied to a slab with an incident radiation field and a polarized primary source of photons.
Modeling the e-APD SAPHIRA/C-RED ONE camera at low flux level
Authors: Lanthermann C. , Anugu N. , Le Bouquin J.-B. , Monnier J. D. , Kraus S. , Perraut K.
Published: April 2019

Context. We implement an electron avalanche photodiode (e-APD) in the MIRC-X instrument, which is an upgrade of the six-telescope near-infrared imager MIRC, at the CHARA array. This technology should improve the sensitivity of near-infrared interferometry.

Aims. We aim to characterize a near-infrared C-RED ONE camera from First Light Imaging (FLI) using an e-APD from Leonardo (previously SELEX).

Methods. We first used the classical mean-variance analysis to measure the system gain and the amplification gain. We then developed a physical model of the statistical distribution of the camera output signal. This model is based on multiple convolutions of the Poisson statistic, the intrinsic avalanche gain distribution, and the observed distribution of the background signal. At low flux level, this model independently constrains the incident illumination level, the total gain, and the excess noise factor of the amplification.

Results. We measure a total transmission of 48 ± 3% including the cold filter and the Quantum Efficiency. We measure a system gain of 0.49 ADU/e, a readout noise of 10 ADU, and amplification gains as high as 200. These results are consistent between the two methods and therefore validate our modeling approach. The measured excess noise factor based on the modeling is 1.47 ± 0.03, with no obvious dependency with flux level or amplification gain.

Conclusions. The presented model allows the characteristics of the e-APD array to be measured at low flux level independently of a preexisting calibration. With < 0.3 electron equivalent readout noise at kilohertz frame rates, we confirm the revolutionary performances of the camera with respect to the PICNIC or HAWAII technologies. However, the measured excess noise factor is significantly higher than what is claimed in the literature (< 1.25), and explains why counting multiple photons remains challenging with this camera.
Economic losses due to health hazards caused by haze event in Johor Bahru, Malaysia
Authors: Hanafi Nur H. , Hassim Mimi H. , Noor Zainura Z. , Ten Joon Y. , Aris Nurazimah M. , Jalil A. A.
Published: April 2019

This study assessed the health risk analysis of haze pollution in Pasir Gudang and Larkin. The relationship between health risk and economic effect due to air pollution exposure in Johor is still poorly understood. Therefore, the objective of this study was to analyse the relationship between air pollution and health. Then, the economic impact due to smoke haze on associated outpatients was calculated. Daily morbidity data from 2014 to 2016 for three haze-related illnesses were collected from two health clinics. Data on air quality were obtained at two Continuous Air Quality Monitoring (CAQM) stations in Johor. Health risks for all age categories in the haze periods were higher than those in non-haze periods. The outpatient morbidity cases in health clinics increased with the rising occurrence of smoke haze in Johor Bahru. The average annual economic losses due to the outpatient health impact of haze were valued at RM83,233 and RM107,486 for Pasir Gudang and Larkin, respectively.
Production of biodiesel from Annona muricata seeds
Authors: Wong Wai-Leong , Lim Waye-Hong , Si Jet , Lam Man-Kee , Ho Yeek-Chia
Published: April 2019

Biodiesel is one of the effective alternative fuels to overcome the problems associated with environmental issues and energy crisis. However, the production of biodiesel from edible oil has provoked the food versus fuel dispute. Thus, a non-edible crop, Annona muricata, is selected as the raw material to produce oil for biodiesel production. In this study, A. muricata oil was extracted with n-hexane at 70 °C for 6 h. Subsequently, the oil was transesterified with methanol and potassium hydroxide (KOH) to produce biodiesel. The significance of transesterification parameters including temperature, time, catalyst concentration, and oil-to-methanol ratio on biodiesel yield (%) was established through two-level factorial design. The factorial design shows that all parameters are significant. Besides, the high content of monounsaturated fatty acid (oleic acid) in the resultant biodiesel suggests that A. muricata biodiesel could display good fuel quality. This hypothesis is proven by the excellent calorific value (39.21 MJ kg-1).
Synthesis of activated carbon doped with transition metals for hydrogen storage
Authors: Ya’aini Nazlina , Pillay A/L Gopala Krishnan Arjun , Ripin Adnan
Published: April 2019

Carbon materials with high porosity and surface area such as activated carbons with a combination of metal possess great materials to obtain maximum hydrogen adsorption via the hydrogen spillover effect. The properties of activated carbon doped with metals (copper, nickel and palladium) were studied to evaluate the capacity of hydrogen sorption on the materials. Characteristics of the activated carbon doped with copper (AC-Cu), nickel (AC-Ni) and palladium (AC-Pd) were evaluated using particle density test, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD) and surface and pore analysis (BET). The performance of hydrogen adsorption of the materials was carried out at different pressures of 50, 100 and 150 psi. Characterization of the materials shows that FTIR spectroscopy manage to detect surface functional groups meanwhile the carbon structure and metal content was determined using XRD. BET analysis shows the presence of oxygen groups was decrease the specific surface area whereas the presence of transition metals had increased the surface area. Hydrogen adsorption test at 150 psi indicates that oxygen groups are not a good adsorption characteristic with only a maximum of 0.39 wt% of hydrogen was adsorbed compared to pristine activated carbon’s 0.42 wt% at 150 psi. The presence of transition metals, copper, nickel and palladium increased the overall hydrogen uptake with 0.52 wt%, 0.44 wt% and 0.62 wt% respectively at 150 psi.
Assessment of prevalence of work-related musculoskeletal disorders among welders in the shipyard industry in Malaysia
Authors: Anwar Johari , Nurul Haznita Abdul Hamid , Mohd Johari Kamaruddin , Mimi Haryani Hassim , Norzita Ngadi , Aishah Abdul Jalil
Published: April 2019

Work-related musculoskeletal disorders (MSDs) are often experienced by welders in the shipyard industry. A study was conducted in one of the shipyards in Malaysia to identify the prevalence of work-related MSDs among welders and the factors attributed to its increase in the workplace. The investigation was carried out using a modified Nordic questionnaire, in which 27 shipyard welders were interviewed. The questions ranged from demographic information to the prevalence of MSDs on parts of body region experiencing discomfort and pain. The results showed that the most affected body regions were neck, upper back, and lower back, which comprised of 74.1%, 70.4%, and 63.0%, respectively, of the respondents being interviewed. A further in-depth study was conducted for the three most affected body regions with respect to work activities such as working posture, repetitive work, and lifting of heavy objects during welding. The frequency of prevalence of work-related MSDs on these body regions experienced by the welders showed that 25.9% of the respondents had frequently encountered neck pain and another 11.1% of them sometimes experienced discomfort while performing repetitive actions. The study also showed that 22.2% of the respondents sometimes experienced shoulder pain whereas 3.7% of them had reported to seldom encountered it when performing welding operation in awkward positions. Almost half of the respondents (i.e., 48.50%) experienced discomfort and pain for both elbow/hand and wrist when lifting objects heavier than 5 kg.
Investigating occupational stress among bus drivers in Universiti Teknologi Malaysia, Johor
Authors: Morshidi Nur Azizah Arryanie , Norafneeza Norazahar
Published: April 2019

This paper presents a study of occupational stress experienced by bus drivers in Universiti Teknologi Malaysia (UTM). The objectives of the study are i) to identify contributing factors leading to high stress among bus drivers and ii) to investigate the effect of occupational stress on bus drivers. A set of questionnaires consisting of demographic information, stressors leading to occupational stress, and strain of occupational stress was distributed to fifteen bus drivers working in UTM. The study used Statistical Package for the Social Sciences (SPSS) to analyse the data and correlation between the contributing factors and occupational stress among the bus drivers. Poor design of bus seat was identified as the leading factors to occupational stress among bus drivers. The bus drivers felt uncomfortable seating and driving for long hours. The seat is not ergonomic to bus driver’s back and body frame. Fatigue, headache, and dizzy are common effects of occupational stress to the bus drivers.
Control of electromagnetic environment in smart traction power supply systems
Authors: Buyakova Natalya , Zakaryukin Vasiliy , Kryukov Andrey
Published: April 2019

The possibility of reducing the intensity of magnetic field created by a traction network of an alternating current electrified railroad is considered in the article. The electric field of such a traction network at a height of 1,8 m above is relatively small. In order to control the electromagnetic situation, 2x25 kV traction systems, sucking transformers with a return wire for the 25 kV system, amplifying and shielding wires of the traction network, passive screens on passenger platforms, optimization of train traffic schedules can be used. Fazonord software package developed at the Irkutsk State Transport University was used as a tool for the analysis of the above events. Using computer simulations, it was shown that the most effective methods for reducing the magnetic field strength are the use of screens on passenger platforms, optimal train schedules, and the use of “soft” train driving modes. The latter measure is able to reduce the peak magnetic field strength by about 25%.
Renovation of the block in Madrid in accordance with criteria of Isover MultiComfort House
Authors: Elistratov Vladimir , Pastukh Olga , Golovina Svetlana , Elistratov Nikolai
Published: April 2019

This study is dedicated to comprehensive approach to the problems connected with living in and operation of the old housing facilities stock of Madrid. The article provides a review to a developed area located in Colonia Ciudad Pegaso in Madrid. This area comprises two four-storeyed residential houses built in 1956, single-storeyed sheds and a small square. It has been found that as at 2017 the existing buildings do not meet the passive house criteria and the territory is not adapted to comfort living of people with limited mobility. Taking into account immediacy of this problem, the article offers the project for renovation of the area concerned. This project was developed within the regular urban program of Madrid called Mad-Re “Madrid Recupera” and the concept of sustainable development. During development of the project the requirements of Isover-Saint Gobain multi-comfort house were taken into account, barrier-free environment for comfortable living of different social groups was created, storage places were reorganized and the territory of the square was adapted to recreation of local citizens. As a result of the above works, there was created a new architectural appearance of the apartment block aimed at prospective development San Blas municipal district of Madrid.
The medieval lime mortars for carrying out dating of monuments (on the example of objects of Abkhazia of the 2-11th c.)
Authors: Pishchulina Victoria , Kotlyar Vladimir , Argun Alkhas
Published: April 2019

Results of research on development of complex techniques of chemical, petrographic, Xray phase and X-ray diffraction methods of medieval lime mortars studying are presented in the article. 12 samples from New Afon, Abkhazia have been studied. Results of analyses have confirmed estimated dates of the second defense line of Anacopia fortress foundation within 570-580 y., reconstruction of Gate tower in 910 – 930 y. and entrance gate – the 950th y. The analysis of lime mortars from screen church near Anacopia (Akuach’s temple) has given time of 650-680 y. Has been revealed that gate in citadel wall have been constructed at the end of II in AD, western tower of a citadel – 680-690 y., reconstruction of the temple of Feodor has been made in 910-930 y. Data of results of a complex research of lime mortars are supported by the documents of the Roman period (2nd century AD), the Byzantine period of the end of the 6th century, construction activity of Abkhazian archons-tsars in the VII-X centuries. The offered methods of researches allow to reconsider the developed approaches to studying of limy mortars and their dating.