bluuebunny/crossref_metadata_2025 huggingface dataset:
1,8-diiodooctane acts as a photo-acid in organic solar cells
Authors: Doumon Nutifafa Y. , Wang Gongbao , Qiu Xinkai , Minnaard Adriaan J. , Chiechi Ryan C. , Koster L. Jan Anton
Published: March 2019

The last decade saw myriad new donor polymers, among which benzodithiophene-co-thienothiophene polymers are attractive due to their relatively high power conversion efficiency in bulk heterojunction solar cells. We examine the effect of UV-light on the stability of these polymers. The relationship between the polymer chemical structure and the UV-stability of the cells is explored on the one hand, and on the other hand, the effect of additives on their UV-stability: 1,8-diiodooctane against 1-chloronaphthalene in the cells and 1,8-octanedithiol in solution. For example, PBDTTT-E with 18% efficiency loss is more stable than PBDTTT-ET with 36% loss throughout the exposure. While 1,8-diiodooctane acts as photo-acid and leads to accelerated degradation of the solar cells, 1-chloronaphthalene does not. Acidity is known to be detrimental to the efficiency and stability of organic solar cells. The degradation is initiated upon UV-irradiation by the cleavage of the side chains, resulting in more electron traps and by the formation of iodine, dissolved HI and carbon-centered radicals from 1,8-diiodooctane as revealed by 1H NMR spectrum. The 1,8-octanedithiol spectra do not show such species. Finally, the mechanisms behind the effect of 1,8-diiodooctane are explained, paving the way for the design of new, efficient as well as stable materials and additives.
Upfront Surgery versus Neoadjuvant Therapy for Resectable Pancreatic Cancer: Systematic Review and Bayesian Network Meta-analysis
Authors: Bradley Alison , Van Der Meer Robert
Published: March 2019

Current treatment recommendations for resectable pancreatic cancer support upfront resection and adjuvant therapy. Randomized controlled trials offering comparison with the emerging neoadjuvant approach are lacking. This review aims to compare both treatment strategies for resectable pancreatic cancer. PubMed, MEDLINE, Embase, Cochrane Database and Cochrane Databases were searched for studies comparing neoadjuvant and surgery-first with adjuvant therapy for resectable pancreatic cancer. A Bayesian network meta-analysis was conducted using the Markov chain Monte Carlo method. Cochrane Collaboration’s risk of bias, ROBINS-I and GRADE tools were used to assess quality and risk of bias of included trials. 9 studies compared neoadjuvant therapy and surgery-first with adjuvant therapy (n = 22,285). Aggregate rate (AR) of R0 resection for neoadjuvant therapy was 0.8008 (0.3636–0.9144)versus0.7515 (0.2026–0.8611) odds ratio (O.R.) 1.27 (95% CI 0.60–1.96). 1-year survival AR for neoadjuvant therapy was 0.7969 (0.6061–0.9500)versus0.7481 (0.4848–0.8500) O.R. 1.38 (95% CI 0.69–2.96). 2-year survival AR for neoadjuvant therapy was 0.5178 (0.3000–0.5970)versus0.5131 (0.2727–0.5346) O.R. 1.26 (95% CI 0.94–1.74). 5-year AR survival for neoadjuvant therapy was 0.2069 (0.0323–0.3300)versus0.1783 (0.0606–0.2300) O.R. 1.19 (95% CI 0.65–1.73). In conclusion neoadjuvant therapy may offer benefit over surgery-first and adjuvant therapy. However, further randomized controlled trials are needed.
High-throughput physical vapour deposition flexible thermoelectric generators
Authors: Morgan Katrina A. , Tang Tian , Zeimpekis Ioannis , Ravagli Andrea , Craig Chris , Yao Jin , Feng Zhuo , Yarmolich Dmitry , Barker Clara , Assender Hazel , Hewak Daniel W.
Published: March 2019

Flexible thermoelectric generators (TEGs) can provide uninterrupted, green energy from body-heat, overcoming bulky battery configurations that limit the wearable-technologies market today. High-throughput production of flexible TEGs is currently dominated by printing techniques, limiting material choices and performance. This work investigates the compatibility of physical vapour deposition (PVD) techniques with a flexible commercial process, roll-to-roll (R2R), for thermoelectric applications. We demonstrate, on a flexible polyimide substrate, a sputtered Bi2Te3/GeTe TEG with Seebeck coefficient (S) of 140 μV/K per pair and output power (P) of 0.4 nW per pair for a 20 °C temperature difference. For the first time, thermoelectric properties of R2R sputtered Bi2Te3 films are reported and we demonstrate the ability to tune the power factor by lowering run times, lending itself to a high-speed low-cost process. To further illustrate this high-rate PVD/R2R compatibility, we fabricate a TEG using Virtual Cathode Deposition (VCD), a novel high deposition rate PVD tool, for the first time. This Bi2Te3/Bi0.5Sb1.5Te3 TEG exhibits S = 250 μV/K per pair and P = 0.2 nW per pair for a 20 °C temperature difference.
Dual-binding pyridine and rhodamine B conjugate derivatives as fluorescent chemosensors for ferric ions in aqueous media and living cells
Authors: Song Fan , Yang Chao , Liu Haibo , Gao Zhigang , Zhu Jing , Bao Xiaofeng , Kan Chun
Published: March 2019

Two new pyridine-type rhodamine B chemosensors (RBPO and RBPF) used to detect Fe3+ have been designed and synthesized, and the sensing behavior towards various metal ions was evaluated via UV–vis and fluorescence spectroscopic techniques.
Multifunctional titanium phosphate nanoparticles for site-specific drug delivery and real-time therapeutic efficacy evaluation
Authors: Cheng Fang-Fang , Sun Panpan , Xiong Wei-Wei , Zhang Yi , Zhang Qiao , Yao Weifeng , Cao Yudan , Zhang Li
Published: March 2019

Folic acid (FA)-functionalized DHE-modified TiP (TiP-PAH-DHE-FA) nanoparticles were synthesized for site-specific drug delivery and real-time therapeutic efficacy evaluation.
Visual detection of Zika virus by isothermal nucleic acid amplification combined with a lateral-flow device
Authors: Lin Xuemei , Wu Maoyong , Wang Wenbiao , Gao Yuhang , Zhang Wei , Wu De , Wu Yina , Zhou Xiaoming , Li Geng
Published: March 2019

The Zika virus (ZIKV) did not receive significant attention in the past until the ZIKV outbreak occurred a few years ago.
Salen-Co(iii) insertion in multivariate cationic metal–organic frameworks for the enhanced cycloaddition reaction of carbon dioxide
Authors: Liu Tao-Tao , Liang Jun , Xu Rui , Huang Yuan-Biao , Cao Rong
Published: March 2019

Salen-Co(iii) was inserted in multivariate cationic metal–organic frameworks for the enhanced cycloaddition reaction of carbon dioxide.
Thermodynamics of adsorption of lysozyme on gold nanoparticles from second harmonic light scattering
Authors: Mishra Kamini , Das Puspendu K.
Published: March 2019

Lysozyme adsorption on gold nanoparticles is an enthalpically driven process while the entropy contribution is favourable but insignificant.
Sorption and condensation of higher hydrocarbons in a Fischer–Tropsch catalyst
Authors: Rößler Stefan , Kern Christoph , Jess Andreas
Published: March 2019

Liquid higher hydrocarbons accumulate inside of heterogeneous catalyst pores, resulting in negative influences on reaction rate as well as product distribution, especially for industrial mm-sized particles.
Impact of freeze–thaw weathering on integrity, internal structure and particle release from micro- and nanostructured cement composites
Authors: Funk Birgit , Göhler Daniel , Sachsenhauser Bernhard , Stintz Michael , Stahlmecke Burkhard , Johnson Blake A. , Wohlleben Wendel
Published: March 2019

Micro- and nanomaterials can i) reduce cement consumption in concrete, ii) improve durability of cement-based constructions and iii) modulate particle release.
Synthesis, anti-mycobacterial and cytotoxic evaluation of substituted isoindoline-1,3-dione-4-aminoquinolines coupled via alkyl/amide linkers
Authors: Rani Anu , Viljoen Albertus , Johansen Matt D. , Kremer Laurent , Kumar Vipan
Published: March 2019

A series of secondary amine-substituted isoindoline-1,3-dione-4-aminoquinolines were prepared via microwave heating and assayed for their anti-mycobacterial activities.
Facile synthesis of polyoxometalates tethered to post Fe-BTC frameworks for esterification of free fatty acids to biodiesel
Authors: Zhang Qiuyun , Liu Xiaofang , Yang Tingting , Yue Caiyan , Pu Quanlin , Zhang Yutao
Published: March 2019

Phosphomolybdic acid was sequentially incorporated into a highly porous metal–organic framework by a one-pot synthesis method, and the prepared composite was used as an efficient and stable solid acid catalyst for biodiesel production.
An atomically efficient, highly stable and redox active Ce0.5Tb0.5Ox (3% mol.)/MgO catalyst for total oxidation of methane
Authors: Sánchez Juan J. , López-Haro Miguel , Hernández-Garrido Juan C. , Blanco Ginesa , Cauqui Miguel A. , Rodríguez-Izquierdo José M. , Pérez-Omil José A. , Calvino José J. , Yeste María P.
Published: March 2019

A very low loading mixed CeO2–TbOx catalyst, supported on MgO, with improved methane total oxidation activity and stability.
A N, S dual doping strategy via electrospinning to prepare hierarchically porous carbon polyhedra embedded carbon nanofibers for flexible supercapacitors
Authors: Li Yanjiang , Zhu Guang , Huang Hailong , Xu Min , Lu Ting , Pan Likun
Published: March 2019

Flexible hierarchically porous carbon polyhedra embedded carbon nanofibers doped with N and S were synthesized as electrodes for flexible supercapacitors.
Revisiting a physiologically based pharmacokinetic model for cocaine with a forensic scope
Authors: Bravo-Gómez María Elena , Camacho-García Laura Nayeli , Castillo-Alanís Luz Alejandra , Mendoza-Meléndez Miguel Ángel , Quijano-Mateos Alejandra
Published: March 2019

A whole-body permeability-rate-limited physiologically based pharmacokinetic (PBPK) model for cocaine was developed with the aim to predict the concentration–time profiles of the drug in blood and different tissues in humans.
A colorimetric sensing platform based on site-specific endonuclease IV-aided signal amplification for the detection of DNA related to the human immunodeficiency virus
Authors: Wang Xiaqing , Huang Zhijun , Chen Junman , Luo Zewei , Xu Ya , Duan Yixiang
Published: March 2019

A colorimetric sensing platform for DNA detection by integrating site-specific endonuclease IV-aided signal amplification and G-quadruplex-hemin DNAzyme.
Peptide nanotube for carbon dioxide chemisorption with regeneration properties and water compatibility
Authors: Geng Rui , Lu Danqin , Lai Yi , Wu Sufen , Xu Zhiai , Zhang Wen
Published: March 2019

A self-assembled heptapeptide-based nanotube for carbon dioxide chemisorption with good regeneration properties and water compatibility was demonstrated.
Divergent synthesis of polysubstituted cyclopropanes and β-silyoxy imidates via switchable additions of N-tert-butanesulfinylimidates to acylsilanes
Authors: Tang Fan , Ma Peng-Ju , Yao Yun , Xu Yan-Jun , Lu Chong-Dao
Published: March 2019

A switchable addition of N-tert-butanesulfinylimidates to acylsilanes leads to divergent synthesis of polysubstituted cyclopropanes and β-silyloxy imidates.
A two-target responsive reversible ratiometric pH nanoprobe: a white light emitting quantum dot complex
Authors: Pramanik Sabyasachi , Roy Shilaj , Mondal Arup , Bhandari Satyapriya
Published: March 2019

Ratiometric pH sensing in the physiological range of pH 6.5–10.3 by a white light emitting quantum dot complex – following the changes in luminescence intensity ratio, color and chromaticity – is described herein.
An untetheredC3v-symmetric triarylphosphine oxide locked by intermolecular hydrogen bonding
Authors: Carroll Timothy G. , Hunt Camden , Garwick Rachel , Wu Guang , Dobrovetsky Roman , Ménard Gabriel
Published: March 2019

AC3v-symmetric triarylphosphine oxide locked into conformation by H-bonding and displaying an extended MOF-like solid-state structure is reported.
Unambiguous hydrogenation of CO2 by coinage-metal hydride anions: an intuitive idea based on in silico experiments
Authors: Habib Md , Sarkar Ritabrata , Biswas Santu , Pramanik Anup , Sarkar Pranab , Pal Sougata
Published: March 2019

Coinage metal hydride anions, especially AgH−, can effectively and deterministically hydrogenate CO2 to HCO2−.
Can the pathway of stepwise nucleation be predicted and controlled?
Authors: Zhang Tian Hui , Zhang Zhi Chao , Cao Jing Sheng , Liu Xiang Yang
Published: March 2019

Microscopic intermediate structures in the microscopic stepwise nucleation (MSN) of a crystal are thermodynamically more stable than the crystalline one.
A unified theory of weak-field coherent control of the behavior of a resonance state
Authors: García-Vela A.
Published: March 2019

A unified theory of weak-field coherent control to modify the whole behavior of a resonance state is proposed.
Recovery and conversion of acetic acid from a phosphonium phosphinate ionic liquid to enable valorization of fermented wastewater
Authors: Reyhanitash Ehsan , Fufachev Egor , van Munster Kaspar D. , van Beek Michael B. M. , Sprakel Lisette M. J. , Edelijn Carmen N. , Weckhuysen Bert M. , Kersten Sascha R. A. , Bruijnincx Pieter C. A. , Schuur Boelo
Published: March 2019

A method was developed to recover and convert a carboxylic acid from a phosphonium phosphinate ionic liquid.
Plutonium assay and isotopic composition measurements in nuclear safeguards samples by inductively coupled plasma mass spectrometry
Authors: Eppich Gary R. , Mácsik Zsuzsanna , Katona Róbert , Konegger-Kappel Stefanie , Stadelmann Guillaume , Köpf Andreas , Varga Beata , Boulyga Sergei
Published: March 2019

MC-ICP-MS methods for accurate and precise determination of Pu amount and isotopic composition at picogram to femtogram levels.
Synthesis of saccharocin from apramycin and evaluation of its ribosomal selectivity
Authors: Sarpe Vikram A. , Pirrone Michael G. , Haldimann Klara , Hobbie Sven N. , Vasella Andrea , Crich David
Published: March 2019

We describe a facile synthesis of saccharocin from apramycin by regioselective tetra-azidation and stereospecific oxidative deamination of the amino group.
Multifunctional phosphoramide-(S)-prolinamide derivatives as efficient organocatalysts in asymmetric aldol and Michael reactions
Authors: Cruz-Hernández Carlos , Landeros José M. , Juaristi Eusebio
Published: March 2019

Knowledge accumulated in the field of organocatalysis led to the design and synthesis of three novel and efficient organocatalysts for the stereoselective aldol and Michael reactions in the presence of water.
Two-dimensional honeycomb-kagome Ta2S3: a promising single-spin Dirac fermion and quantum anomalous hall insulator with half-metallic edge states
Authors: Zhang Liang , Zhang Chang-wen , Zhang Shu-Feng , Ji Wei-xiao , Li Ping , Wang Pei-ji
Published: March 2019

Recent experimental success in the realization of two-dimensional (2D) magnetism has invigorated the search for new 2D magnetic materials with a large magnetocrystalline anisotropy, high Curie temperature, and high carrier mobility.
Controlled modification of skyrmion information in a three-terminal racetrack memory
Authors: Wang Kang , Qian Lijuan , Ying See-Chen , Xiao Gang , Wu Xiaoshan
Published: March 2019

We propose in a racetrack memory the modification of skyrmion information, and study the coupling between two oscillatory modes of skyrmions.
Synthesis of a sumanenyl hafnocene complex
Authors: Amaya Toru , Katoh Shun , Moriuchi Toshiyuki , Hirao Toshikazu
Published: March 2019

A convex-bound sumanenyl hafnocene complex was selectively synthesized, and the catalytic activity of sumanenyl metallocenes was demonstrated in the carboalumination reaction.
A novel method for the preparation of solvent-free, microwave-assisted and nitrogen-doped carbon dots as fluorescent probes for chromium(vi) detection and bioimaging
Authors: Cao Meng , Li Yong , Zhao Yunze , Shen Chongyang , Zhang Hongyan , Huang Yuanfang
Published: March 2019

Herein, N-doped carbon dots with excellent fluorescence characteristics were prepared by a solvent-free, microwave-assisted method and employed for the fluorometric detection of Cr(vi) and bioimaging.
Catalytic ozonation process using a MgO nano-catalyst to degrade methotrexate from aqueous solutions and cytotoxicity studies in human lung epithelial cells (A549) after treatment
Authors: Alinejad Abdolazim , Akbari Hamed , Ghaderpoori Mansour , Jeihooni Ali Khani , Adibzadeh Amir
Published: March 2019

Pharmaceutical compounds which enter the environment are classified as emerging pollutants.
Towards sensor applications of a polymer/Ag nanoparticle nanocomposite film
Authors: Yeshchenko O. A. , Malynych S. Z. , Polomarev S. O. , Galabura Yu. , Chumanov G. , Luzinov I.
Published: March 2019

We demonstrated the capability of a nanocomposite film made of Ag nanoparticles embedded into a polymer matrix to detect presence of organic vapors.
Generation of engineered core–shell antibiotic nanoparticles
Authors: Varaprasad Kokkarachedu , Yallapu Murali Mohan , Núñez Dariela , Oyarzún Patricio , López Matias , Jayaramudu Tippabattini , Karthikeyan Chandrasekaran
Published: March 2019

Antibiotic ZnO–curcumin core–shell nanoparticles were prepared via an ultra-sonication process. ZnO–curcumin exhibited excellent antibacterial capacity compared to the commercial antibiotic amoxicillin.
Continuous-flow synthesis of 3,5-disubstituted pyrazolesviasequential alkyne homocoupling and Cope-type hydroamination
Authors: Ötvös Sándor B. , Georgiádes Ádám , Ozsvár Dániel , Fülöp Ferenc
Published: March 2019

A telescoped continuous-flow method is presented for the synthesis of 3,5-disubstituted pyrazolesviacopper-mediated alkyne homocoupling and Cope-type hydroamination of the intermediary 1,3-dialkynes.
The construction of self-supported thorny leaf-like nickel-cobalt bimetal phosphides as efficient bifunctional electrocatalysts for urea electrolysis
Authors: Sha Linna , Yin Jinling , Ye Ke , Wang Gang , Zhu Kai , Cheng Kui , Yan Jun , Wang Guiling , Cao Dianxue
Published: March 2019

Urea electrolysis offers the prospect of cost-effective and energy-saving hydrogen production together with mitigating urea-rich wastewater pollution instead of overall water splitting.
Constructing a highly oriented layered MOF nanoarray from a layered double hydroxide for efficient and long-lasting alkaline water oxidation electrocatalysis
Authors: Yang Lin , Zhu Guilei , Wen Hao , Guan Xin , Sun Xun , Feng Hao , Tian Wenli , Zheng Dengchao , Cheng Xiaowei , Yao Yadong
Published: March 2019

Template-directed synthesized Fe0.1-Ni-MOF nanoarray (Fe0.1-Ni-MOF/NF) behaves efficiently as an electrocatalyst for alkaline water oxidation with a strong electrochemical durability.
A fused-ring non-fullerene acceptor based on a benzo[1,2-b:4,5-b′]dithiophene central core with a thieno[3,2-b]thiophene side-chain for highly efficient organic solar cells
Authors: Jia Yu , Zhang Yun , Jiang Wei , Su Bin , Liu Chunbo , Zhu Enwei , Che Guangbo
Published: March 2019

The BTT-FIC-based device achieved a champion PCE of 12.65% for the benzo[1,2-b:4,5-b′]di(cyclopenta[2,1-b:3,4-b′]dithiophene)-containing NFAs based OSCs.
Modulation of proteostasis and protein trafficking: a therapeutic avenue for misfolded G protein-coupled receptors causing disease in humans
Authors: Ulloa-Aguirre Alfredo , Janovick Jo Ann
Published: March 2019

Proteostasis refers to the process whereby the cell maintains in equilibrium the protein content of different compartments. This system consists of a highly interconnected network intended to efficiently regulate the synthesis, folding, trafficking, and degradation of newly synthesized proteins. Molecular chaperones are key players of the proteostasis network. These proteins assist in the assembly and folding processes of newly synthesized proteins in a concerted manner to achieve a three-dimensional structure compatible with export from the endoplasmic reticulum to other cell compartments. Pharmacologic interventions intended to modulate the proteostasis network and tackle the devastating effects of conformational diseases caused by protein misfolding are under development. These include small molecules called pharmacoperones, which are highly specific toward the target protein serving as a molecular framework to cause misfolded mutant proteins to fold and adopt a stable conformation suitable for passing the scrutiny of the quality control system and reach its correct location within the cell. Here, we review the main components of the proteostasis network and how pharmacoperones may be employed to correct misfolding of two G protein-coupled receptors, the vasopressin 2 receptor and the gonadotropin-releasing hormone receptor, whose mutations lead to X-linked nephrogenic diabetes insipidus and congenital hypogonadotropic hypogonadism in humans respectively.
Enhanced circuit for linear ring VCO‐ADCs
Authors: Borgmans J. , Rombouts P.
Published: March 2019

Recently an extremely linear voltage‐controlled ring‐oscillator for use in VCO‐ADCs was proposed by Babaie‐Fishani and Rombouts. In this current Letter, a circuit‐level technique to improve the bandwidth and noise performance of such a linear VCO is proposed. The key element is the modified delay cell, where the traditional cross‐coupled inverters are modified into ‘feed‐forward’ coupling inverters that pre‐charge the subsequent elements in the ring. The resulting circuit maintains the excellent linearity, but has greatly enhanced bandwidth (up to 3 times higher) and considerably reduced power for the same circuit noise level (up to 2.5 times lower).
Conservation voltage reduction of networked microgrids
Authors: Constante Gonzalo , Abillama Joseph , Illindala Mahesh , Wang Jiankang
Published: March 2019

This study proposes a strategy for coordinated operation of networked microgrids (MGs), distributed energy resources (DERs), and volt‐VAR control devices in the implementation of volt‐VAR optimisation (VVO). The authors’ formulation is focused on implementing conservation voltage reduction, although it can be extended for any other VVO problems. They consider the voltage–power control modes of DERs contemplated in IEEE Std. 1547, namely, constant power factor, voltage–reactive power, active–reactive power, and constant reactive power. DERs are considered at the distribution network (DN) and within the MGs. The problem is formulated as a bi‐level optimisation problem where the DN operator (DNO) is in the upper‐level and each MG in the lower‐level. The DNO and each MG are assumed to be players with their individual objective functions. Finally, they validate their formulation in two test systems: a 9‐node system and a modified IEEE 33‐node system. On average the proposed method can improve the efficiency of the grid by 4% compared to the economic operation scenario. The results of the study show that the different control modes of the DERs can have better performance depending on the objective of the VVO formulation. The findings of this study are compelling for the implementation of VVO in active distribution systems with networked MGs.
First detection of oscillations in the Halo giant HD 122563: Validation of seismic scaling relations and new parameters
Authors: Creevey O. , Grundahl F. , Thévenin F. , Corsaro E. , Pallé P. L. , Salabert D. , Pichon B. , Collet R. , Bigot L. , Antoci V. , Andersen M. F.
Published: March 2019

Aims. The nearby metal-poor giant HD 122563 is an important astrophysical laboratory in which to test stellar atmospheric and interior physics. It is also a benchmark star for which to calibrate methods to apply to large scale surveys. Recently it has been remeasured using various methodologies given the new high precision instruments at our disposal. However, inconsistencies in the observations and models have been found.

Methods. In order to better characterise this star using complementary techniques we have been measuring its radial velocities since 2016 using the Hertzsprung telescope (SONG network node) in order to detect oscillations.

Results. In this work we report the first detections of sun-like oscillations in this star, and to our knowledge, a detection in the most metal-poor giant to date. We applied the classical seismic scaling relation to derive a new surface gravity for HD 122563 of log gν = 1.39 ± 0.01. Reasonable constraints on the mass imposed by its PopII giant classification then yields a radius of 30.8 ± 1.0 ℛ⊙. By coupling this new radius with recent interferometric measurements we infer a distance to the star of 306 ± 9 pc. This result places it further away than was previously thought and is inconsistent with the HIPPARCOS parallax. Independent data from the Gaia mission corroborate the distance hypothesis (dGDR2 = 290 ± 5 pc), and thus the updated fundamental parameters.

Conclusions. We confirm the validity of the classical seismic scaling relation for surface gravity in metal-poor and evolved star regimes. The remaining discrepancy of 0.04 dex between log gGDR2 (= 1.43 ± 0.03) reduces to 0.02 dex by applying corrections to the scaling relations based on the mean molecular weight and adiabatic exponent. The new constraints on the Hertzsprung–Russell diagram (L⋆ν = 381 ± 26 ℒ⊙) significantly reduce the disagreement between the stellar parameters and evolution models, however, a discrepancy of the order of 150 K still exists. Fine-tuned stellar evolution calculations show that this discrepancy can be reconciled by changing the mixing-length parameter by an amount (−0.35) that is in agreement with predictions from recent 3D simulations and empirical results. Asteroseismic measurements are continuing, and analysis of the full frequency data complemented by a distance estimate promises to bring important constraints on our understanding of this star and of the accurate calibration of the seismic scaling relations in this regime.
Flattened loose particles from numerical simulations compared to particles collected by Rosetta
Authors: Lasue J. , Maroger I. , Botet R. , Garnier Ph. , Merouane S. , Mannel Th. , Levasseur-Regourd A. C. , Bentley M. S.
Published: March 2019

Context.Cometary dust particles are remnants of the primordial accretion of refractory material that occurred during the initial formation stages of the solar system. Understanding their physical structure can help constrain their accretion process.

Aims.The in situ study of dust particles that were collected at slow speeds by instruments on board the Rosetta space mission, including GIADA, MIDAS, and COSIMA, can be used to infer the physical properties, size distribution, and typologies of the dust.

Methods.We have developed a simple numerical simulation of aggregate impact flattening to interpret the properties of particles collected by COSIMA. The aspect ratios of flattened particles from simulations and observations are compared to distinguish between initial families of aggregates that are characterized by different fractal dimensionsDf. This dimension can differentiate between certain growth modes: the diffusion limited cluster–cluster aggregates (DLCA,Df≈ 1.8), diffusion limited particle–cluster aggregates (DLPA,Df≈ 2.5), reaction limited cluster–cluster aggregates (RLCA,Df≈ 2.1), and reaction limited particle–cluster aggregates (RLPA,Df≈ 3.0).

Results.The diversity of aspect ratios measured by COSIMA is consistent with either two families of aggregates with different initialDf(a family of compact aggregates withDfclose to 2.5–3 and some fluffier aggregates withDf≈ 2) or aggregates formed by a single type of aggregation process, such as DLPA. In that case, the cohesive strength of the dust particles must span a wide range to explain the range of aspect ratios observed by COSIMA. Furthermore, variations in cohesive strength and velocity may play a role in the detected higher aspect ratio range (>0.3).

Conclusions.Our work allows us to explain the particle morphologies observed by COSIMA and those generated by laboratory experiments in a consistent framework. Taking into account all observations from the three dust instruments on board Rosetta, we favor an interpretation of our simulations based on two different families of dust particles with significantly distinct fractal dimensions that are ejected from the cometary nucleus.
Phase mixing of nonlinear Alfvén waves
Authors: Prokopyszyn A. P. K. , Hood A. W. , De Moortel I.
Published: March 2019

Aims. This paper presents 2.5D numerical experiments of Alfvén wave phase mixing and aims to assess the effects of nonlinearities on wave behaviour and dissipation. In addition, this paper aims to quantify how effective the model presented in this work is at providing energy to the coronal volume.

Methods. The model is presented and explored through the use of several numerical experiments which were carried out using the Lare2D code. The experiments study footpoint driven Alfvén waves in the neighbourhood of a two-dimensional x-type null point with initially uniform density and plasma pressure. A continuous sinusoidal driver with a constant frequency is used. Each experiment uses different driver amplitudes to compare weakly nonlinear experiments with linear experiments.

Results. We find that the wave trains phase-mix owing to variations in the length of each field line and variations in the field strength. The nonlinearities reduce the amount of energy entering the domain, as they reduce the effectiveness of the driver, but they have relatively little effect on the damping rate (for the range of amplitudes studied). The nonlinearities produce density structures which change the natural frequencies of the field lines and hence cause the resonant locations to move. The shifting of the resonant location causes the Poynting flux associated with the driver to decrease. Reducing the magnetic diffusivity increases the energy build-up on the resonant field lines, however, it has little effect on the total amount of energy entering the system. From an order of magnitude estimate, we show that the Poynting flux in our experiments is comparable to the energy requirements of the quiet Sun corona. However a (possibly unphysically) large amount of magnetic diffusion was used however and it remains unclear if the model is able to provide enough energy under actual coronal conditions.
Rocky super-Earths or waterworlds: the interplay of planet migration, pebble accretion, and disc evolution
Authors: Bitsch Bertram , Raymond Sean N. , Izidoro Andre
Published: March 2019

Recent observations have found a valley in the size distribution of close-in super-Earths that is interpreted as a signpost that close-in super-Earths are mostly rocky in composition. However, new models predict that planetesimals should first form at the water ice line such that close-in planets are expected to have a significant water ice component. Here we investigate the water contents of super-Earths by studying the interplay between pebble accretion, planet migration and disc evolution. Planets’ compositions are determined by their position relative to different condensation fronts (ice lines) throughout their growth. Migration plays a key role. Assuming that planetesimals start at or exterior to the water ice line (r > rH2O), inward migration causes planets to leave the source region of icy pebbles and therefore to have lower final water contents than in discs with either outward migration or no migration. The water ice line itself moves inward as the disc evolves, and delivers water as it sweeps across planets that formed dry. The relative speed and direction of planet migration and inward drift of the water ice line is thus central in determining planets’ water contents. If planet formation starts at the water ice line, this implies that hot close-in super-Earths (r < 0.3 AU) with water contents of a few percent are a signpost of inward planet migration during the early gas phase. Hot super-Earths with larger water ice contents on the other hand, experienced outward migration at the water ice line and only migrated inwards after their formation was complete either because they become too massive to be contained in the region of outward migration or in chains of resonant planets. Measuring the water ice content of hot super-Earths may thus constrain their migration history.
Discovery of a second pulsating intermediate helium-enriched sdOB star
Authors: Latour M. , Green E. M. , Fontaine G.
Published: March 2019

We present the discovery of long-period, low-amplitude, g-mode pulsations in the intermediate He-rich hot subdwarf (sdOB) star Feige 46. So far, only one other He-enriched sdOB star (LS IV−14 ° 116) was known to exhibit such pulsations. From our ground-based light curves of Feige 46, we extracted five independent periodicities ranging from 2294 s to 3400 s. We fit our optical spectrum of the star with our grid of non-local thermodynamic equilibrium (NLTE) model atmospheres and derived the following atmospheric parameters: Teff = 36120 ± 230 K, log g = 5.93 ± 0.04, and log N(He)/N(H) = −0.32 ± 0.03 (formal fitting errors only). These parameters are very similar to those of LS IV−14 ° 116 and place Feige 46 well outside of the instability strip where the hydrogen-rich g-mode sdB pulsators are found. We used the Gaia parallax and proper motion of Feige 46 to perform a kinematic analysis of this star and found that it likely belongs to the Galactic halo population. This is most certainly an intriguing and interesting result given that LS IV−14 ° 116 is also a halo object. The mechanism responsible for the pulsations in these two peculiar objects remains unclear, but a possible scenario involves the ϵ-mechanism. Although they are the only two members in their class of variable stars, these pulsators appear to have more in common than just their pulsation properties.
Optimal bilinear control problem related to a chemo-repulsion system in 2D domains
Authors: Guillén-González Francisco , Mallea-Zepeda Exequiel , Rodríguez-Bellido María Ángeles
Published: March 2019

In this paper, we study a bilinear optimal control problem associated to a chemo-repulsion model with linear production term in a bidimensional domain. The existence, uniqueness and regularity of strong solutions of this model are deduced, proving the existence of a global optimal solution. Afterwards, we derive first-order optimality conditions by using a Lagrange multipliers theorem.
The XYZ mesons: what they aren’t
Authors: Olsen Stephen Lars
Published: March 2019

I discuss the properties of some representative XYZ mesons in the context of the most commonly proposed models for their underlying nature.
Measurements with doubly-charmed hadrons in LHCb
Authors: Vieira Daniel
Published: March 2019

The LHCb experiment has been collecting large amounts of charm data, making it possible to perform precise measurements and search for rare particles. In 2017, the LHCb collaboration reported the first observation of the doubly charmed baryon, the $ \Xi _{cc}^{ + + } $. In 2018, the first measurement of the $ \Xi _{cc}^{ + + } $ lifetime, using the same decay and dataset, was published. This paper summarizes the content of both analyses, as reported in the 9th International Workshop on Charm Physics, in Novosibirsk, Russia.
Implication of chiral symmetry on charm meson spectroscopy
Authors: Du Meng-Lin
Published: March 2019

It is demonstrated that, if the lightest positive parity charm mesons are assumed to owe their existence to non-perturbative Goldstone boson-D/D∗ scattering, various puzzles in the charm meson spectrum get resolved. Most importantly the ordering of the lightest strange and non-strange scalars becomes natural. Furthermore, it is demonstrated that the amplitudes for Goldstone boson-D/D∗ scattering are fully consistent with the high quality data on decay B−→ D+π−π− provided by LHCb. It implies that the lowest positive-parity charm mesons are dynamically generated rather than quark-antiquark states.
Lattice Evidence for Bound Heavy Tetraquarks
Authors: Francis Anthony , Hudspith Renwick J. , Lewis Randy , Maltman Kim
Published: March 2019

We investigate the possibility of qq'$ \bar {Q}\bar {Q}' $ tetraquark bound states using nf = 2 + 1 lattice QCD with pion masses ≃ 164, 299 and 415 MeV. Two types of lattice interpolating operator are chosen, reflecting first diquarkantidiquark and second meson-meson structure. Performing variational analysis using these operators and their mixings, we determine the ground and first excited states from the lattice correlators. Using non-relativistic QCD to simulate the bottom quarks and the Tsukuba formulation of relativistic heavy quarks for charm quarks, we study the ud$ \bar {b}\bar {b} $, ℓs$ \bar {b}\bar {b} $ as well as ud$ \bar {c}\bar {b} $, channels with ℓ= u, d. In the case of the ud$ \bar {b}\bar {b} $ and ℓs$ \bar {b}\bar {b} $ channels unambiguous signals for JP=1+ tetraquarks are found with binding energies 189(10) and 98(7) MeV below the corresponding free two-meson thresholds at the physical point. These tetraquarks are therefore strong-interaction stable, implying they are stable under strong as well as electromagnetic interactions while they can decay weakly. So far these are the first exotic hadrons predicted to have this feature. Further evidence for binding is found in the ud$ \bar {c}\bar {b} $ channel, whereby the binding energy broadly straddles the electromagnetic stability threshold. Studying further the quark mass dependence we vary the heavy quark mass in ud$ \bar {Q}\bar {Q} $, ℓs$ \bar {Q}\bar {Q} $ as well as ud$ \bar {Q}\bar {b} $, ℓs$ \bar {Q}\bar {b} $ between roughly 0.7 and 6.3 times the bottom quark mass. The observed mass dependence of these four flavor channels closely follows a behaviour argued from phenomenological considerations of the heavy baryon spectrum.
Effect of surface treatment by sandblasting on the quality and electrochemical corrosion properties of a C-1020 carbon steel used by an Algerian oil company
Authors: HAMMOUDA Nadia , BELMOKRE Kamel
Published: March 2019

The purpose of the different operations under the term surface preparation is to get a clean surface able to be coated. It is essential to adapt this preparation in terms of the metallurgical nature of the substrate, cleanliness, its shape and roughness. Surface preparations especially the operations of sandblasting, polishing, or grinding prove of capital importance. It allows to modify the superficial properties of these materials, after these treatments the surface becomes very active. This paper evaluates the mechanical surface treatments effect by sandblasting (Sa 1.5 and Sa 2.5) on the electrochemical corrosion characteristics of C-1020 carbon steel in 3% NaCl solution electrolyte simulating aggressive sea atmosphere. Investigations are conducted using stationary (free potential "E-t, polarization curves "E-i", the Tafel rights and the Rp) and nonstationary electrochemical tools such as electrochemical impedance. The results obtained allowed us to highlight that sandblasted carbon steel degrades with immersion time because of the roughness of the surface. These results were confirmed by the plot of the electrochemical impedance diagrams, confirming that the process governing kinetics is under charge transfer control. Good protection against corrosion cannot be obtained only with a good surface preparation of the adapted steel.
Generalized active disturbance rejection control for the boiler-turbine unit using multi-objective optimization and extended state observer
Authors: Zhu Jianzhong , Wu Xiao , Shen Jiong , Wang Meihong
Published: March 2019

This paper proposes a generalized active disturbance rejection controller (GADRC) based hierarchical control structure for the boilerturbine unit. In the lower layer, a multivariable extended state observer (MESO) is developed to estimate the values of the lumped disturbances caused by modelling mismatches, fuel quality variation and wide range load variation. The influence of the disturbances is then compensated at the input side as a feedforward control. In the upper layer, the multi-objective optimization is devised to obtain the set-points by removing the plant behaviour variation from the optimized model in a feasible way. The lowpass filter acting on the lumped disturbances is designed to bridge the gap between the lower and upper layer. The impact of the feedthrough item is approximated by a first-order system and a two degree-of-freedom (2-DOF) control strategy is established to illustrate the set-point tracking and disturbance rejection properties of the controller. Simulation studies on a 1000MWe coal-fired ultra-supercritical boiler-turbine unit demonstrate that the proposed control strategy can achieve a satisfactory performance in cases of fuel quality variations, model-plant mismatches and wide range load variation.
Facile synthesis of NFL-ZnWO4 for pseudocapacitor applications
Authors: Fan Xiao , Chen Xuyuan
Published: March 2019

In this report, NFL-ZnWO4 was synthesized by a hydrothermal route and investigated for application in supercapacitors for the first time. The physical and chemical characterizations of the prepared nanomaterial were analyzed by SEM, EDS, XRD and XPS, respectively. Supercapacitors study of CV, GCD and EIS revealed that NFL-ZnWO4 exhibits good electrochemical properties. The high specific capacitance value of 107.7 F g-1 was achieved at 5 mV s−1. These findings demonstrated that ZnWO4 could be a promising electrode material candidate and highly desirable for application of high property supercapacitors in the future.
Structural damage detection based on improved frequency change ratio
Authors: WANG Jian , JIN Huan , MA Xiao , ZHAO Bin , YANG Zhi , LIU Yaduo , WANG Yi , WANG Xian
Published: March 2019

Frequency Change Ratio (FCR) based damage detection methodology for structural health monitoring (SHM) is analyzed in detail. The effectiveness of damage localization using FCR for some slight damage cases and worse ones are studied on an asymmetric planar truss numerically. Disadvantages of damage detection using FCR in practical application are found and the reasons for the cases are discussed. To conquer the disadvantages of FCR, an Improved Frequency Change Ratio (IFCR) based damage detection method which takes the changes of mode shapes into account is proposed. Verification is done in some damage cases and the results reveal that IFCR can identify the damage more efficiently. Noisy cases are considered to assess the robustness of IFCR and results indicate that the proposed method can work well when the noise is not severe.
Viscous-flow-based investigation of Cloaking phenomenon among multi-floating bodies and experimental verification
Authors: Wang Z K , He G H , Zhang Z G , Meng Y H
Published: March 2019

The safety of mooring systems on offshore platforms seems more and more significant with the utilization of offshore space and resources, so the reduction of wave drift force is the key issue in this wave-body interaction problem. The wave drift force acting on the inner floating body surrounded by multiple small floating bodies can be reduced obviously with the occurrence of a phenomenon, which is called the Cloaking phenomenon. The Cloaking phenomenon refers to the reduction or complete elimination in amplitude of the scattered waves. In this paper, a real-coded genetic algorithm was used to optimize the parameters of outer floating bodies to minimize the scattered wave energy, and then the wave drift force acting on the inner body can be reduced. Furthermore, associated CFD simulations and experimental research were conducted with the above optimized parameters to investigate and verify the Cloaking phenomenon more systemically. It is shown that the wave drift force acting on the inner floating body in the Cloaking configuration can be reduced obviously both in numerical and experimental research, and the reduction of the wave drift force is closely related to the change of wave field around the structure.
Flight manoeuvring and safe flight visualization with the aid of wide-ranging scrutiny and automation software
Authors: Jeyan J V Muruga Lal , Lal Jency , Kumar M Senthil , Anwar Arfaj Ahamed
Published: March 2019

This document guides to an efficient use of FDVCAS system. FDVCAS is a reconstruction, playback, interactive visualization tool, which collects, stores, processes, analyses and present the flight data in high fidelity graphical presentation in 2D and 3D format. It synchronizes and presents in both graphical and synthetic visual form to the extends of analysing the impact of the data on the system in 3D graphic animation. The existing process involves in capturing the data from different input sources and formats, analysing the features of the data monitoring is done manually in offline in a unsynchronized fashion, This is difficult, time consuming and requires highly skilled technical expertise as it is visualized in plain data form. The above standard procedures followed shall be integrated and automated with minimum intelligence to be built, in with the system. In order to analyse the flight data in a coherent way it is required to integrate both 2D and 3D form The proposed concept is the Development of a system with a single solution by providing data display, graphical charts and replay features with a sophisticated graphical user interface, which is super imposed on the outside window imagery. FDVCAS consists of Bypass data acquisition system, Outside Window Imagery (OWI) system with graphical analyser. Bypass data acquisition system receives data from aircraft recorder and transmits the data in engineering format to FDVCAS system. The OWI system has three main modules namely, 3D Visual module, GUI based Graphical analyser and Warning display module. The warnings and the graphical plots are super imposed on the 3D Visual.
Fin based active control for ship roll motion stabilization
Authors: Patil Neha Sunil , Chandra Dubey Awanish , Anantha Subramanian V
Published: March 2019

Ship roll motion control is important for vessels engaged in oceanographic research activities and this paper focuses on the design of a controller for fin based roll motion stabilization of a Coastal Research Vessel (CRV). Based on the geometry of a pair of actuator fins installed at the midship of the vessel, the hydrodynamic coefficients are calculated for the vessel including the fin lift capacity. The wave disturbances are simulated as a sine time series. The objective is to design a Linear Quadratic Regulator (LQR), a state feedback controller and obtain the performance of the system. The larger objective is to implement the system eventually in laboratory scale physical simulations in wave environment. This paper primarily presents the design of the control system and evaluation through Simulink in Matlab environment. The global cost function of the system is minimized by precision tuning of the two control parameters (or weighting matrices), Q and R. The system analysis is done using frequency domain and state space approach. The simulation results show that the natural frequency and roll response closely match with the response of the physical model (CRV) in laboratory environment, as observed during the experimental study. The proposed control system is compared with a conventional PID controller. The simulation results demonstrate the effectiveness of the designed roll motion stabilization system with significant roll reduction over the operational range of the vessel.