bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of condition‐based maintenance considering partial opportunities
Authors: Truong‐Ba Huy , Borghesani Pietro , Cholette Michael E. , Ma Lin 
Published: December 2019

AbstractRecent studies have demonstrated the economic benefit of exploiting partial opportunities for maintenance, which arise from the reduction of costs of doing partial maintenance utilizing the opportunity given. A typical example is an externally induced production stop with a duration that may not be sufficient to a complete maintenance activity. This paper combines partial opportunities and condition‐based maintenance (CBM) strategies and proposes an innovative maintenance optimization method considering time‐varying economic conditions. This scenario naturally fits a broad range of assets with a finite design life (including long‐life machinery and infrastructure), operating under variable economic conditions and usage‐intensities. The maintenance optimization problem is formulated in this study as a finite‐horizon Markov decision process, where the randomly occurring opportunities are accounted for by augmenting the time‐varying, decision‐dependent transition probabilities. A dynamic programming approach is subsequently used to obtain the optimal CBM policy, consisting of time‐varying thresholds on equipment condition and the cost of conducting maintenance during the arrived opportunity. A case study of such a maintenance policy for an induced draft fan of a sugar production system located in Queensland, Australia, is undertaken to evaluate the benefits of the proposed methodology against more traditional approaches that neglect opportunities or consider only replete opportunity durations.
Spatially restricted Double Z‐Simplified Box Orbital basis sets: Optimization and comparison with some standard basis sets
Authors: García Victor , Sánchez‐Márquez Jesús , Torres Estefanía , Zorrilla David , Fernández Manuel 
Published: December 2019

AbstractAs part of previous studies, we introduced a new type of basis function named Simplified Box Orbitals (SBOs) that belong to a class of spatially restricted functions which allow the zero differential overlap (ZDO) approximation to be applied with complete accuracy. The original SBOs and their Gaussian expansions SBO‐3G form a minimal basis set, which was compared to the standard Slater‐type orbital basis set (STO‐3G). In the present paper, we have developed the SBO basis functions at double‐zeta (DZ) level, and we have assessed the option of expanding the SBO‐DZ as a combination of Gaussian functions. Finally, we have determined the quality of the new basis set by comparing the molecular properties calculated with SBO‐nG with those achieved with some standard basis sets.
Asynchronous fault detection observer design for discrete‐time piecewise linear systems
Authors: Wang Xiao‐Lei , Yang Guang‐Hong 
Published: December 2019

SummaryThis paper studies the problem of asynchronous fault detection (FD) observer design for piecewise linear systems. Considering that the states of the FD observer and the system may stay at different regions of the state space, asynchronous FD observers are designed at different instants to cope with the challenges incurred by exogenous disturbances and fault signals. By employing new piecewise Lyapunov functions that depend on the different regions where the states are located, it is proved that the proposed asynchronous FD observers ensure the stability andH∞performance of the error systems. Three examples are given to show that the new design scheme provides better FD results than the existing design methods.
An observer‐based output feedback robust MPC approach for constrained LPV systems with bounded disturbance and noise
Authors: Ping Xubin , Yang Sen , Wang Peng , Li Zhiwu 
Published: December 2019

SummaryThe present paper addresses an observer‐based output feedback robust model predictive control for the linear parameter varying system with bounded disturbance and noise subject to input and state constraints. The main contribution is that the on‐line convex optimization problem not only simultaneously optimizes the observer and controller gains to stabilize the augmented closed‐loop system but also incorporates the refreshment of bounds of the estimation error set. The optimization problem steers the nominal augmented closed‐loop system to converge to the origin, and the real augmented closed‐loop system bounded within robust positive invariant set converges to a neighborhood of the origin such that recursive feasibility of the optimization and robust stability of the controlled system are ensured. Two numerical examples are given to illustrate the effectiveness of the method.
Ethylene Oligomerization Study Bearing Nickel (II) and Cobalt (II) Complexes with N, O‐Donor Schiff Bases as Ligands
Authors: Liu Jinyi , Wang Jun , Chen Liduo , Zhang Na , Lan Tianyu , Wang Libo 
Published: December 2019

AbstractA series of novel nickel 1–4 {[Ni(L1)] (1); [Ni(L2)Cl2] (2); [Ni(L3)Cl2] (3); [Ni(L4)Cl2] (4)} and cobalt complexes 5–8 {[Co(L1)] (5); [Co(L2)Cl2] (6); [Co(L3)Cl2] (7); [Co(L4)Cl2] (8)}bearing N, O‐donor Schiff bases as ligands L1‐L4 (L1= (E)‐2‐(((2‐phenoxyethyl)imino)methyl)‐phenol; L2= (E)‐5‐methoxy‐2‐(((2‐phenoxyethyl)imino)methyl)phenol; L3= (E)‐2‐(((2‐(2‐methox yphenoxy)ethyl)imino)methyl)phenol; L4= (E)‐5‐methoxy‐2‐(((2‐(2‐methoxyphenoxy)ethyl)imino) methyl)phenol) were synthesized from the complex reaction between salicylaldehyde and phenoxye‐thylamine analogues and characterized by UV‐Vis, IR, 1H NMR, ESI‐MS and elemental analysis. All the nickel complexes (1‐4) and cobalt complexes (5‐8) as catalyst precursors were evaluated in detail with methylaluminoxane (MAO) as an activator in the ethylene oligomerization. At the same time, the effects of reaction parameters, catalyst structures and solvent on ethylene oligomerization were investigated too. As a result, complexes 5–8 showed a better catalytic activity (2.05‐3.38×105 g/(mol(Co)•h) and a higher selectivity of 34.44% toward the valuable C8 compound using toluene as the solvent than complexes 1–4.
High‐Efficiency Photocatalysis of Self‐Hydroxylated TiO2 Nanocrystals for Water Splitting
Authors: Yu Siqi , Fan Chenyao , Han Bing , Qian Guodong , Wang Zhiyu 
Published: December 2019

AbstractHerein, a facile and controllable strategy to synthesize self‐hydroxylated TiO2 nanocrystals with promoted photocatalytic activity in hydrogen evolution is demonstrated. Various colors (yellow, light yellow, blueish gray and gray) in appearance are induced by controlling the molar ratio of titanium source to oxidant during the hydrothermal treatment. Compared with commercial P25 TiO2 nanoparticles, the as‐obtained self‐hydroxylated TiO2 nanocrystals exhibit better photocatalytic performance in H2 evolution. Specifically, the maximum hydrogen evolution rate under solar light illumination (10.0 mmol/h/g) is 4.6 times superior to that of P25. The characterization results confirm the presence of abundant hydroxyls resulting from the hydrothermal treatment, which decreases the recombination rate of carriers and the energy barrier of hydrogen formation while facilitates light absorption for promoting photocatalytic performance.
Hollow TiN Nanospheres as Advanced Host Materials for High Performance Lithium‐Sulfur Batteries
Authors: Luo Jie , Zheng Jianming , Dang Bo 
Published: December 2019

AbstractTo improve the electrochemical performance of lithium‐sulfur batteries, the issues of poor electronic conductivity and shuttle effect of soluble polysulfide must be solved. In this work, hollow mesoporous TiN nanospheres are developed and designed as host materials for the lithium‐sulfur batteries. The as‐prepared TiN/S composites show initial high specific capacity of 1316 mAh g−1 at the current density of 0.1 C. Furthermore, the TiN/S composites deliver superior cycle stability and excellent rate capability. The superior electrochemical performance could be ascribed to the following advantages: (a) The presence of TiN could enhance the electronic conductivity; (b) The mesoporous structure is beneficial for inhibiting the shuttle effect of soluble polysulfide.
Controlled One‐Pot Synthesis of Multiple Heterocyclic Scaffolds Based on an Amphiphilic Claisen‐Schmidt Reaction Intermediate
Authors: Song Rong , Yu Hui , Huang Haowen , Chen Yun 
Published: December 2019

AbstractAn efficient one‐pot synthesis method for multiple heterocyclic scaffolds was carried out based on the cyano‐containing amphiphilic Claisen‐Schmidt reaction intermediate. Several valuable heterocyclic compounds including isoindolinone, flavonoid and isobenzofuranone were conveniently synthesized from o‐cyanobenzaldehyde and o‐hydroxyacetophenone by controlling the reaction temperature, catalyst and solvent. In addition, a density functional theory (DFT) based calculation was carried out on the key amphiphilic intermediate for understanding the reaction selectivity in water and non‐aqueous solution.
In‐silico and In‐vitro Studies on the DNA/BSA‐Binding Features of a Mixed Ligand Copper (II) Complex Containing 2‐Methyl Imidazole and a Schiff Base Ligand
Authors: Mohamadi Maryam , Rezaei Azadeh , Ebrahimipour S. Yousef , Falahati‐pour Soudeh Khanamani , Mohamadizadeh Fatemeh , Bemani Mahdeih , Hajizadeh Mohammad Reza , Mirzaei Mohammad Reza , Khoshdel Alireza , Mahmoodi Mehdi 
Published: December 2019

AbstractThe study aimed at investigating the binding features of the mixed ligand Copper (II) complex to BSA and DNA. Both in‐silico and in‐vitro analyses were made to fully assess the binding mechanism and mode of the Copper (II) complex to BSA and DNA. Spectroscopic tests demonstrated the Copper (II) complex reacted with DNA through binding to its minor grooves with the association constant 3.36×103 M−1. This type of interaction was confirmed by molecular docking simulations. Tryptophan quenching analyses at 298, 303 and 308 K showed that the Copper (II) complex reacted with the BSA's ground‐state fluorophore and created a non‐fluorescent adduct. In other words, a static quenching approach was offered with the quenching rate constants within the span of 3.4×1012‐1.28×1013 M−1s−1. Besides, the values of binding constants at various temperatures were achieved, implying the moderate similarity of the Copper (II) complex to the serum's albumin. Research on thermodynamic factors suggested the complex‐BSA bond was an enthalpy‐induced reaction where Van der Waals forces and the hydrogen bond performed the leading role. The simulations of molecular docking verified the test results and demonstrated the amino acids engaged in the bond between BSA and the Copper (II) complex.
One‐Pot Functionalization of 8‐Aminoquinolines through the Acylation and Regioselective C5‐H Halogenation under Transition‐Metal‐Free Conditions
Authors: Li Dandan , Jia Zhenzhen , Jiang Yongshuai , Jia Jingpeng , Zhao Xiaowei , Li Zehui , Xu Zhihong 
Published: December 2019

AbstractA mild and efficient functionalization of 8‐aminoquinolines has been demonstrated through the acylation and regioselective C5‐H halogenation in one pot under transition metal free conditions. This method enables the acyl halides acting as the donors of both acyl and halide atoms. Moremover, different type of acyl halides could be employed in this reaction and proceeded smoothly to afford the corresponding halogenated products in moderate to good yields. The protocol is operationally simple, facile, and might have potential application in synthesis of 5‐halogenated quinoline scaffolds.
Influence of Green Tea and Basil Extracts on Cassava Starch Based Films as Assessed by Thermal Degradation, Crystalline Structure, and Mechanical Properties
Authors: Medina‐Jaramillo Carolina , Bernal Celina , Famá Lucía 
Published: December 2019

AbstractNatural extracts are investigated as plasticizers of starch–glycerol biobased films for food coating applications. For this purpose, films with cassava starch, glycerol, and distilled water with and without green tea or basil extracts are obtained by solvent casting. The plasticizing effect of the extracts is confirmed from the films crystalline structure, thermal degradation behavior, glass transition temperature, and tensile properties. Increased mobility of starch chains is the result of a strong interaction between extract components and starch molecules. The Kohlrausch–Williams–Watts (KWW) theoretical modeling, used for the first time to determine the effect of antioxidant components in starch films, also confirms the plasticizing effect of either green tea or basil extracts. In addition, the original luminosity of the starch film is not compromised by the incorporation of the extracts. Moreover, a delay in the starch retrogradation is achieved, making the film more durable and hence, very promising to be used as food coating.
Tensorial generalization of characters
Authors: Itoyama H. , Mironov A. , Morozov A. 
Published: December 2019

AbstractIn rainbow tensor models, which generalize rectangular complex matrix model (RCM) and possess a huge gauge symmetry U(N1) × … × U(Nr), we introduce a new sub-basis in the linear space of gauge invariant operators, which is a redundant basis in the space of operators with non-zero Gaussian averages. Its elements are labeled by r-tuples of Young diagrams of a given size equal to the power of tensor field. Their tensor model averages are just products of dimensions:$$ \left\langle \chi {R}_1,\dots, {R}_r\right\rangle \sim {C}_{R_1},\dots {,}_{R_r}\left({N}_1\right)\dots {D}_{R_r}\left({N}_r\right) $$χR1…Rr∼CR1,…,RrN1…DRrNrof representationsRiof the linear group SL(Ni), with$$ {C}_{R_1},\dots {,}_{R_r} $$CR1,…,Rr,made of the Clebsch­Gordan coefficients of representationsRiof the symmetric group. Moreover, not only the averages, but the operators$$ {\chi}_{\overrightarrow{R}} $$χR→themselves exist only when these$$ {C}_{\overrightarrow{R}} $$CR→are non-vanishing. This sub-basis is much similar to the basis of characters (Schur functions) in matrix models, which is distinguished by the property \character) ~character,which opens a way to lift the notion and the theory of characters (Schur functions) from matrices to tensors. In particular, operators$$ {\chi}_{\overrightarrow{R}} $$χR→are eigenfunctions of operators which generalize the usual cut-and­join operators$$ \hat{W} $$Ŵ;they satisfy orthogonality conditions similar to the standard characters, but they do not form afulllinear basis for all gauge-invariant operators, only for those which have non-vanishing Gaussian averages.
Modelling time efficiency of cobot-supported kit preparation
Authors: Fager Patrik , Calzavara Martina , Sgarbossa Fabio 
Published: December 2019

AbstractKitting – meaning to supply assembly with components in presorted kits – is widely seen as beneficial for assembly quality and efficiency when there is a multitude of component variants. However, the process by which kits are prepared – the kit preparation – is labour-intensive, and kit errors are problematic at assembly processes. The use of robotics to support kit preparation has received some attention by researchers, but literature is lacking with respect to how collaborative robots – cobots – can support kit preparation activities. The purpose of this paper is to identify the potential of a cobot to support time-efficient batch preparation of kits. To address the purpose, the paper presents a mathematical model for estimation of the cycle time associated with cobot-supported kit preparation. The model is applied in a numerical example with experimental data from laboratory experiments, and cobot-supported kit preparation is compared with manual kit preparation. The findings suggest that cobot-supported kit preparation is beneficial with diverse kits and smaller components quantities per SKU (Stock Keeping Unit) and provides less variability of the outcome, when compared to manual kit preparation. The paper reveals several insights about cobot-supported kit preparation that can be valuable for both academics and practitioners. The model developed can be used by practitioners to assess the potential of cobots to support kit-batch preparation in association with assembly, spare parts, repair and maintenance, or business to business industry.
High shocking and pacing impedances due to defibrillation lead calcification
Authors: Hauser Robert G. , Sengupta Jay , Casey Susan , Tang Chuen , Stanberry Larissa I. , Abdelhadi Raed 
Published: December 2019

Abstract
Purpose
We have reported the calcification of Endotak defibrillation leads that required replacement. The aim of this study was to assess calcified Endotak Reliance leads in the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database and compare them to calcified Sprint Fidelis, Sprint Quattro Secure, Riata, and Durata leads in MAUDE.

Methods
We searched the MAUDE database from 2008 to 2019 for defibrillation lead calcification using the terms “calcium,” “calcification,” and “calcified”. Included were explanted leads whose manufacturers found calcium on the shocking and/or pacing electrode.

Results
The MAUDE search identified 113 calcified defibrillation leads that qualified for the study, including 109 Endotak Reliance leads, 1 Sprint Quattro Secure lead, 2 Durata leads, 1 Riata ST lead, and no Sprint Fidelis lead. The sign of calcification was a gradual increase in shocking or pacing impedance. Average implant time was 7.4 ± 3.1 (range: 1.3–16.5) years. Only Endotak Reliance leads had shocking coil calcification (n = 72; 66.0%) and five (6.9%) of these failed defibrillation threshold (DFT) testing. Distal pacing electrode calcification affected 55 (50.4%) Endotak Reliance leads. The four other leads had pacing ring electrode calcification only.

Conclusion
Endotak Reliance defibrillation leads appear prone to shocking coil and/or distal pacing electrode calcification. High impedances may compromise defibrillation and pacing therapy. Patients who have these leads should be monitored; those exhibiting high shocking impedances should be considered for DFT testing. Lead replacement should be considered for pacemaker-dependent patients whose leads exhibit progressively high impedances.
Lyapunov Exponents of Two Stochastic Lorenz 63 Systems
Authors: Geurts Bernard J. , Holm Darryl D. , Luesink Erwin 
Published: December 2019

AbstractTwo different types of perturbations of the Lorenz 63 dynamical system for Rayleigh–Bénard convection by multiplicative noise—called stochastic advection by Lie transport (SALT) noise and fluctuation–dissipation (FD) noise—are found to produce qualitatively different effects, possibly because the total phase-space volume contraction rates are different. In the process of making this comparison between effects of SALT and FD noise on the Lorenz 63 system, a stochastic version of a robust deterministic numerical algorithm for obtaining the individual numerical Lyapunov exponents was developed. With this stochastic version of the algorithm, the value of the sum of the Lyapunov exponents for the FD noise was found to differ significantly from the value of the deterministic Lorenz 63 system, whereas the SALT noise preserves the Lorenz 63 value with high accuracy. The Lagrangian averaged version of the SALT equations (LA SALT) is found to yield a closed deterministic subsystem for the expected solutions which is isomorphic to the original Lorenz 63 dynamical system. The solutions of the closed chaotic subsystem, in turn, drive a linear stochastic system for the fluctuations of the LA SALT solutions around their expected values.
Surface Pressure Reconstruction from Phase Averaged Deflectometry Measurements Using the Virtual Fields Method
Authors: Kaufmann R. , Ganapathisubramani B. , Pierron F. 
Published: December 2019

AbstractIn this study, pressure distributions were reconstructed from phase-locked surface deformation measurements on a thin plate. Slope changes on the plate surface were induced by an external flow interacting with the specimen and measured with a highly sensitive deflectometry setup. The Virtual Fields Method (VFM) was used to obtain pressure reconstructions from the processed surface slopes and the plate material constitutive mechanical parameters. The applicability of the approach in combination with phase-locked measurements is demonstrated using a synthetic jet setup generating a periodic flow in air. Phase-averaging slope data allows mitigating random noise effects and resolving low-range differential pressure amplitudes despite the turbulent flow. The size of the spatial structures of the investigated low amplitude flow events identified in full-field with the present method are $\mathcal {O}(1)~\text {mm}$O(1)mm, which is beyond the capabilities of other available surface pressure measurement techniques. Challenges and limitations in achieving the metrological performance for resolving the observed surface slopes of $\mathcal {O}(0.1)~\text {mm km}^{-1}$O(0.1)mm km−1 are described and improvements for future applications are discussed.
Comparison between manta trawl and in situ pump filtration methods, and guidance for visual identification of microplastics in surface waters
Authors: Karlsson Therese M. , Kärrman Anna , Rotander Anna , Hassellöv Martin 
Published: December 2019

AbstractOwing to the development and adoption of a variety of methods for sampling and identifying microplastics, there is now data showing the presence of microplastics in surface waters from all over the world. The difference between the methods, however, hampers comparisons, and to date, most studies are qualitative rather than quantitative. In order to allow for a quantitative comparison of microplastics abundance, it is crucial to understand the differences between sampling methods. Therefore, a manta trawl and an in situ filtering pump were compared during realistic, but controlled, field tests. Identical microplastic analyses of all replicates allowed the differences between the methods with respect to (1) precision, (2) concentrations, and (3) composition to be assessed. The results show that the pump gave higher accuracy with respect to volume than the trawl. The trawl, however, sampled higher concentrations, which appeared to be due to a more efficient sampling of particles on the sea surface microlayer, such as expanded polystyrene and air-filled microspheres. The trawl also sampled a higher volume, which decreased statistical counting uncertainties. A key finding in this study was that, regardless of sampling method, it is critical that a sufficiently high volume is sampled to provide enough particles for statistical evaluation. Due to the patchiness of this type of contaminant, our data indicate that a minimum of 26 particles per sample should be recorded to allow for concentration comparisons and to avoid false null values. The necessary amount of replicates to detect temporal or spatial differences is also discussed. For compositional differences and size distributions, even higher particle counts would be necessary. Quantitative measurements and comparisons would also require an unbiased approach towards both visual and spectroscopic identification. To facilitate the development of such methods, a visual protocol that can be further developed to fit different needs is introduced and discussed. Some of the challenges encountered while using FTIR microspectroscopic particle identification are also critically discussed in relation to specific compositions found.