bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on mechanical properties and fracturing behavior of Carrara marble with the flat‐jointed model
Authors: Cheng Yi , Wong Louis Ngai Yuen 
Published: January 2020

SummaryOvercoming two inherent limitations presented by the standard bonded‐particle model (BPM), the flat‐jointed model still lacks extensive application. This study hereby conducts a comprehensive investigation on the application of the flat‐jointed model in rock mechanics study. First, after a careful examination on the mechanical behavior of the flat‐joint contact, a systematic calibration has been conducted to build numerical models matching the mechanical properties of Carrara marble. Second, the validated model is used to simulate the fracturing behavior of marble specimens containing a single or en‐echelon flaws. Finally, the appearance of particle flow code (PFC) models has been compared with the results obtained from optical observation in order to establish a possible correlation between PFC models and real marble regarding microcracking behavior. Discussions suggest that to remove the particle size effect, the model resolution (ratio of sample dimension to the average particle diameter) should be larger than 30 in the flat‐jointed model and 150 in the BPM, respectively. Results from the above investigations suggest that the flat‐jointed model is capable of matching both the mechanical properties and fracturing behavior of Carrara marble. The numerical model is more reliable to predict the fracturing path at the instant of initiation than at failure. Development of initial fractures is not only controlled by the magnitude of tension force but also influenced by the extent of distribution of tension force. The appearance and components of a fracture in flat‐jointed models probably reveal not only its property (tensile or shear) but also the corresponding microcracking behavior of real rocks.
High order convergent modified nodal bi‐cubic spline collocation method for elliptic partial differential equation
Authors: Singh Suruchi , Singh Swarn 
Published: January 2020

AbstractA high order modified nodal bi‐cubic spline collocation method is proposed for numerical solution of second‐order elliptic partial differential equation subject to Dirichlet boundary conditions. The approximation is defined on a square mesh stencil using nine grid points. The solution of the method exists and is unique. Convergence analysis has been presented. Moreover, the superconvergent phenomena can be seen in proposed one step method. The numerical results clearly exhibit the superiority of the new approximation, in terms of both accuracy and computational efficiency.
A Novel Conjugated Polymer Consists of Benzimidazole and Benzothiadiazole: Synthesis, Photophysics Properties, and Sensing Properties for Pd2+
Authors: Liu Kuan , Hu Zijun 
Published: January 2020

ABSTRACTA conjugated polymer PPBIBTE based on benzimidazole and benzothiadiazole was synthesized through palladium‐catalyzed sonogashira cross‐coupling reaction. The chemical structures of the monomers and the polymer were indicated by 1H NMR, and investigation of photophysics properties and sensing optical properties for metal ions were observed by ultraviolet–visible and photoluminescence spectroscopy. PPBIBTE showed remarkable selectivity for Pd2+ by “turn‐off” fluorescence sensing progress. In addition, the Stern–Volmer and Benesi‐Hildebrand plots were used to reveal the interaction between the polymer and Pd2+, while job's method was applied to calculate the determination of stoichiometry. The results demonstrate that PPBIBTE can utilize static quenching for Pd2+ by forming a 1:1 complex. And it is a potential sensing material as fluorescence chemosensor for Pd2+ with high selectivity and sensitivity. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 831‐842
A novel MTTF estimator and associated parameter estimation method on heavily censoring data
Authors: Jiang Renyan 
Published: January 2020

AbstractMany reliability and maintenance decision problems need to estimate mean‐time‐to‐failure (MTTF) of a particular product component and/or build its life distribution model as early as possible based on field failure data. The field failure data are often heavily censored. In this case, the exponential‐assumption–based method can considerably overestimate the MTTF, and the classical parameter estimation methods such as the maximum likelihood method (MLM) cannot provide robust estimates. This paper aims to address this issue through proposing a novel method to estimate the MTTF and life distribution parameters. The proposed method first derives a nonparametric estimator of MTTF based on the decomposition of the integral expression of the theoretical MTTF and sample statistical characteristics. The estimated MTTF is then combined with a two‐step single‐parameter MLM to estimate the distribution parameters. A numerical experiment is carried out, and a real‐world dataset is analyzed. The results show that the proposed method can provide accurate and robust estimates for the MTTF and distribution parameters. The method is applicable for any life distribution and offers practitioners an efficient tool for reliability analysis.
Porous versus Dense ‐ Effect of Silica Coating on Contrast Enhancement of Iron Carbide Nanoparticles in T2‐Weighted Magnetic Resonance Imaging
Authors: Ahmadpoor Fatemeh , Delavari H. Hamid , Shojaosadati Seyed Abbas 
Published: January 2020

AbstractMagnetic nanoparticles development is an intense subject in various biomedical applications. Among these applications, magnetic nanoparticles as contrast agents are of special interest for improving the diagnostic accuracy of magnetic resonance imaging (MRI). We report here the synthesis of magnetic iron carbide nanoparticles and their stabilization in aqueous media. The challenge of achieving phase transfer of hydrophobic iron carbide nanoparticles to hydrophilic media was addressed by silica shell. Silica coated iron carbide nanoparticles were fabricated with both mesoporous and dense silica shells followed by investigating the impact of such a coating on their performance as T2‐negative contrast agents in MRI. The crystalline structure of silica coated iron carbide nanoparticles was confirmed via X‐ray diffraction (XRD) analysis. Fourier transform infrared spectroscopy (FTIR) demonstrated formation of the silica coating and transmission electron microscopy (TEM) confirmed the core@shell morphology of silica coated iron carbide nanoparticles. Mesoporous and dense silica coated iron carbide nanoparticles exhibited high transverse relaxivity values of 457 and 365 mM−1s−1, respectively. The enhanced MRI efficiency obtained from the silica coated iron carbide nanoparticles highlights these core@shell structures as promising negative contrast agents. Based on the results, the nature of silica coating both in porous or dense forms has a significant effect on water relaxivity which makes the iron carbide@mesoporous silica nanoparticles highly efficient T2 contrast agents.
Adsorption Isotherm, Kinetic and Mechanism Studies on the Surface Modification of SiC powder with Disperse Black BL
Authors: Sun Shichao , Zhai Chaoyang , Liu Jiaxiang 
Published: January 2020

AbstractWell dispersed modified SiC powder was prepared via disperse black BL (DBBL). High density SiC green body was prepared by the modified SiC powder. The modified SiC powder was obtained via putting in 1.2 wt% DBBL through agitating for 2 h. The slurry obtained by modified SiC powder with a 50 vol % solid content has a viscosity of 0.430 Pa⋅s. The dense SiC green body (2.43 g/cm3) was obtained via slip casting. The electron microscopy as well as thermogravimetry were applied to determine the adsorption of the modifier on the SiC powder. Experimental data shows that the adsorption kinetics equation of DBBL on the SiC powder obeys the pseudo‐first‐order kinetics model. And the isotherm equation agrees with the Langmuir model. The experiment dates indicate that the adsorption mode of DBBL was physical adsorption.
Correlation of Distribution Functions of Hydrogen Adsorption and Disodium Maleate Hydrogenation Activity for the Nickel Catalyst in Aqueous Solution
Authors: Afineevskii Andrei V. , Prozorov Dmitrii A. , Knyazev Alexander V. , Osadchaya Tatiana Y. 
Published: January 2020

AbstractIn the design of a chemical process, both chemical thermodynamics and chemical kinetics matter. The article is devoted to solving the problem of finding the relation between these approaches. The effects of the nature and composition of solvents onto the thermodynamic characteristics of the adsorption states of hydrogen adsorbed on nickel and onto the activity of the nickel catalyst were studied. For these purposes, the following was done: (i) differential heats of hydrogen adsorption in a wide range of surface coverage and maximum quantity of adsorbed hydrogen were determined by adsorption calorimetry on partially deactivated nickel catalyst from solutions; (ii) the activity of the catalyst for the corresponding systems was measured from kinetic experiments. The correlation between a catalyst activity and an adsorption energy distribution of hydrogen adsorbed was reported, it will subsequently predict the activity of the catalyst without experiment.
Methods for Synthesis of Chiral Alcohols and Their Conversion to Heterocycles Containing Bi‐2‐Naphthyl Moiety
Authors: Periasamy Mariappan , Venkanna Boda , Mohan Lakavathu 
Published: January 2020

AbstractConvenient methods were developed for the preparation of chiral alcohols containing bi‐2‐naphthyl moiety in 92–96% yields. The substituted 1,4‐diols containing bi‐2‐naphthyl moiety were further converted to N‐substituted pyrrolidine derivatives in 72%‐76% yields via the corresponding dimesylate followed by reaction with primary amines. Interestingly, the corresponding chiral tetrahydrofuran derivative was obtained in 90% yield by self condensation of the dimesylate in the absence of primary amines. The results are discussed considering the reaction mechanisms involved in these transformations.
A Smartphone‐Assisted Sensitive, Selective and Reversible Recognition of Copper Ions in an Aqueous Medium
Authors: Kumar Arvind , Bera Anuradha , Kumar Satish 
Published: January 2020

AbstractA photochromic substituted spiropyran (8‐methoxy‐1,3’,3’‐trimethylspiro[chromene‐2,2’indoline]) was successfully synthesized and its structural integrity was ascertained using spectroscopic methods. Owing to the uniquely positioned methoxy and phenolic groups for potential coordination with a metal ion, it was investigated for the recognition of toxic metal ions. The spiropyran derivative responded to the presence of Cu2+ ions in an aqueous solution by displaying a color change visible to the naked eye (colorless to pink). The color change was witnessed due to the Cu2+ ion‐induced transformation of the closed‐form (spiro) of the substituted spiropyran derivative into an open merocyanine (MC) form, which complexes the Cu2+ ion. The color change was further used for the quantification of Cu2+ ion concentration in water using a smartphone captured digital images via pixel intensity analysis. The spiropyran derivative displayed 0.24±0.01 μM, 0.65±0.06 μM (0.61±0.06 μM using paper strips) as the LOD for Cu2+ ions using UV‐Visible spectroscopy and digital colorimetry, respectively. The density functional theory (DFT) calculations and Job's plot supported the formation of a 2 : 1 (H: G) complex between the spiropyran derivative and copper ions. The time‐dependent DFT (TD‐DFT) investigations were also used to understand the color change during the complex formation, which indicated a good correlation between the experimental and theoretical results at the molecular level.
Palladium Nitrosyl Carboxylate Complexes as Catalysts for C−H/C−H Oxidative Coupling of Arenes: An Experimental and DFT Study
Authors: Shishilov Oleg , Shamsiev Ravshan , Akhmadullina Nailya , Flid Vitaly 
Published: January 2020

AbstractOxidative C−H/C−H coupling of arenes were carried out on palladium nitrosyl carboxylates Pd3(NO)2(CX3CO2)4(ArH)2 (I: X=Cl, Ar=Ph; II: X=F, Ar=Tol) under relatively mild conditions (5 bars of O2, 110 °C, 24 h). Over trifluoroacetate complex II, we obtained higher yields in both homocoupling of benzene and heterocoupling of benzene and other arenes. The catalytic system showed high selectivity over 90 % for all the studied substrates. The DFT calculations on the activation of arene through the proton transfer showed that the activation energies for all possible intramolecular pathways are much higher than those for the proton transfer to free carboxylate ions, indicating that the presence of external base is required to increase the performance of the considered catalytic system. In the catalytic tests it was found that the preferable external bases are ions of strong carboxylic acids, while acetate provides almost negligible improvement and pyridine suppresses the reaction most likely due to binding to active sites on palladium.
Can a system dynamics model of the emergency department show which levers reduce bottlenecks and delays to improve access to care?
Authors: McAvoy Sue , Staib Andrew , Treston Gregory 
Published: January 2020

AbstractThe purpose of this paper is to demonstrate through practical application how a system dynamics (SD) patient flow model of an emergency department (ED) can show which levers effectively reduce backlogs to improve access to care. Overcrowded EDs are struggling to meet demand and access targets. In 2016 and 2017, in the UK and Australia, respectively, 15% and 28% of arrivals waited longer than the targeted 4‐hr treatment time. Historically, simulation models that have informed access to emergency care have ignored the wider systems impacts. There is a growing awareness of the value of systems analysis tools for informing interventions and policy. In this study, we constructed a pilot system dynamics patient flow model, where the scope was the ambulatory and ambulance patient arrivals, the ED processes for acute and fast‐track pathways, pathology and radiology services, the ED short‐stay unit, and the Medical Assessment Planning Inpatient Unit. Patients queued to access constrained ED resources (doctors and beds) and diagnostic services (pathology and X‐ray). The model was tested on actual data from five separate historical periods spanning 3 years. The resultant daily pattern of peaks and troughs in patient flow and system delays accurately replicated patterns in actual patient flows, resource use, and the location of delays. “What if” scenario analysis (b) simulated how access would have looked in the sample weeks with different intervention strategies, (b) simulated system limits on the basis of current resources, (c) accurately identified levers that historically have been most effective at minimizing ambulance ramping, and (d) identified when additional staffing would fail to improve flow.
When is a spherical body of constant diameter of constant width?
Authors: Lassak Marek 
Published: January 2020

AbstractWe prove that a smooth convex body of diameter $$\delta < \frac{\pi }{2}$$δ<π2 on the d-dimensional unit sphere $$S^d$$Sd is of constant diameter $$\delta $$δ if and only if it is of constant width $$\delta $$δ. We also show this equivalence for all convex bodies on $$S^2$$S2. Since, as shown earlier, the equivalence on $$S^d$$Sd is true for every $$\delta \ge \frac{\pi }{2}$$δ≥π2, the question whether spherical bodies of constant diameter and constant width on $$S^d$$Sd coincide remains open for non-smooth bodies on $$S^d$$Sd, where $$d\ge 3$$d≥3.
QTL mapping and successful introgression of the spring wheat-derived QTL Fhb1 for Fusarium head blight resistance in three European triticale populations
Authors: Ollier Marine , Talle Vincent , Brisset Anne-Laure , Le Bihan Zoé , Duerr Simon , Lemmens Marc , Goudemand Ellen , Robert Olivier , Hilbert Jean-Louis , Buerstmayr Hermann 
Published: January 2020

AbstractKey messageThe spring wheat-derived QTLFhb1was successfully introgressed into triticale and resulted in significantly improved FHB resistance in the three triticale mapping populations.AbstractFusarium head blight (FHB) is a major problem in cereal production particularly because of mycotoxin contaminations. Here we characterized the resistance to FHB in triticale breeding material harboring resistance factors from bread wheat. A highly FHB-resistant experimental line which derives from a triticale × wheat cross was crossed to several modern triticale cultivars. Three populations of recombinant inbred lines were generated and evaluated in field experiments for FHB resistance using spray inoculations during four seasons and were genotyped with genotyping-by-sequencing and SSR markers. FHB severity was assessed in the field by visual scorings and on the harvested grain samples using digital picture analysis for quantifying the whitened kernel surface (WKS). Four QTLs with major effects on FHB resistance were identified, mapping to chromosomes 2B, 3B, 5R, and 7A. Those QTLs were detectable with bothFusariumseverity traits. Measuring of WKS allows easy and fast grain symptom quantification and appears as an effective scoring tool for FHB resistance. The QTL on 3B collocated withFhb1, and the QTL on 5R with the dwarfing geneDdw1. This is the first report demonstrating the successful introgression ofFhb1into triticale. It comprises a significant step forward for enhancing FHB resistance in this crop.
Rotary compression in tool cavity—a new ductile fracture calibration test
Authors: Pater Zbigniew , Tomczak Janusz , Bulzak Tomasz , Wójcik Łukasz , Lis Konrad 
Published: January 2020

AbstractDuctile fracture is one of the most common failure modes in hot metal forming. It can be predicted by means of so-called damage functions that describe the relation between stress, deformation and fracture initiation. A practical use of these functions requires the knowledge of the critical damage value of the material that is determined by calibration tests based on compression, tension and torsion. For the prediction to be correct, one must ensure that the modelled and real stresses are in agreement. Previous studies did not offer any effective test for determining critical values of damage under changing load conditions that occur in cross and skew rolling processes, among others. To compensate for this knowledge gap, researchers at the Lublin University of Technology have developed a new test consisting in rotary compression of a test-piece in a cavity between the tools, which is described in this paper. In the proposed test, a cylindrical test-piece is rolled over a cavity (impression) created by grooves on two mating tools. The cavity height is smaller than the test-piece diameter. At the critical value of the forming length, the state of stress induced thereby in the test-piece axis causes fracture. Knowing the critical forming length, it is possible to determine the critical value of damage by numerical modelling. The practical application of the proposed test is illustrated through the case of C45 grade steel subjected to forming in the temperature range 950–1150 °C. The analysis makes use of the normalized Cockcroft-Latham (NCL) criterion of ductile fracture.
Impact of a combined pulsed electric field (PEF) and enzymatic mash treatment on yield, fermentation behaviour and composition of white wine
Authors: Fauster T. , Philipp C. , Hanz K. , Scheibelberger R. , Teufl T. , Nauer S. , Scheiblhofer H. , Jaeger H. 
Published: January 2020

AbstractThe aim of this work was to study the combined application of a pulsed electric field (PEF) and an enzymatic treatment to white wine mash. The resulting impact of membrane permeabilisation by electroporation and pectin degradation by enzymes on fermentation behaviour and quality of white wine was assessed. The mash of two varieties, Traminer and Grüner Veltliner, was PEF treated (3 and 10 kJ/kg) using a continuous co-linear treatment chamber. Pectinases were added immediately afterwards and maceration was performed for 4 and 24 h. Various physico-chemical parameters were analysed at different stages of the production process and the impact of the combined treatment on volatile compounds such as esters and terpenes was analysed by gas chromatography–mass spectrometry and a sensory panel in the final white wine after bottling and storage. Regardless of the PEF treatment intensity, the variety and the maceration time, the release of juice was not significantly influenced. For Traminer, the fermentation time was reduced through the enhanced extraction of nitrogen from 322 to 359 mg/L due to PEF treatment (10 kJ/kg). The release of phenols which were localized in the pulp, were significantly more affected than phenols from the skin. Although the concentration of selective esters especially of the variety Traminer significantly increased, the sensory evaluation indicated no positive effect on the olfactory properties. Overall, the combination of PEF and enzyme pretreatment showed benefits in reducing the fermentation time and increasing the content of selective esters for Traminer.
Initial experience with [18F]DPA-714 TSPO-PET to image inflammation in primary angiitis of the central nervous system
Authors: Backhaus Philipp , Roll Wolfgang , Beuker Carolin , Zinnhardt Bastian , Seifert Robert , Wenning Christian , Eisenblätter Michel , Thomas Christian , Schmidt-Pogoda Antje , Strunk Daniel , Wagner Stefan , Faust Andreas , Tüttelmann Frank , Röpke Albrecht , Jacobs Andreas H. , Stummer Walter , Wiendl Heinz , Meuth Sven G. , Schäfers Michael , Grauer Oliver , Minnerup Jens 
Published: January 2020

Abstract
Purpose
Primary angiitis of the central nervous system (PACNS) is a heterogeneous, rare, and poorly understood inflammatory disease. We aimed at non-invasive imaging of activated microglia/macrophages in patients with PACNS by PET-MRI targeting the translocator protein (TSPO) with [18F]DPA-714 to potentially assist differential diagnosis, therapy monitoring, and biopsy planning.

Methods
In total, nine patients with ischemic stroke and diagnosed or suspected PACNS underwent [18F]DPA-714-PET-MRI. Dynamic PET scanning was performed for 60 min after injection of 233 ± 19 MBq [18F]DPA-714, and MRI was simultaneously acquired.

Results
In two PACNS patients, [18F]DPA-714 uptake patterns exceeded MRI correlates of infarction, whereas uptake was confined to the infarct in four patients where initial suspicion of PACNS could not be confirmed. About three patients with PACNS or cerebral predominant lymphocytic vasculitis showed no or only faintly increased uptake. Short-term [18F]DPA-714-PET follow-up in a patient with PACNS showed reduced lesional [18F]DPA-714 uptake after anti-inflammatory treatment. Biopsy in the same patient pinpointed the source of tracer uptake to TSPO-expressing immune cells.

Conclusions
[18F]DPA-714-PET imaging may facilitate the diagnosis and treatment monitoring of PACNS. Further studies are needed to fully understand the potential of TSPO-PET in deciphering the heterogeneity of the disease.