bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical properties of extruded glass fiber reinforced thermoplastic polyolefin composites
Authors: Ghanbari Abbas , Sadat Jalili Negin , Haddadi Seyyed A. , Arjmand Mohammad , Nofar Mohammadreza 
Published: June 2020

AbstractEngineered structural materials are required to feature a combination of deformability (ductility) and strength to be considered damage‐tolerant for safety‐critical applications. These two mechanical properties, however, tend to be mutually exclusive, encouraging optimization of the trade‐off between strength and toughness. In this report, an elastomer and a glass fiber were incorporated into a blend of two grades of polypropylene (PP) to improve matrix toughness through both intrinsic and extrinsic toughening mechanisms. This study investigates the impact resistance (at 23°C and −30°C), and strength, stiffness, deformability, and processability of extruded compatibilized glass fiber reinforced thermoplastic polyolefin (TPO) composites at 23°C. For the hybrid composites contribution of different toughening mechanisms in attainment of the final impact strength is governed by the testing temperature and processing (extruder screw) speed. The intrinsic toughening mechanism induced by the presence of the ethylene α‐olefin copolymer is suppressed by the introduction of glass fiber at 23°C, irrespective of screw speed and screw configuration design. The heat distortion temperature (HDT), flexural modulus, and tensile strength exhibit a marked improvement by glass fiber inclusion at 23°C. By evaluating the performance of the composites at −30°C, it was observed that the impact energy of the elastomer modified hybrid composites may be enhanced in the same manner as the glass fibers toughen the brittle unmodified PP matrix. It was noted that contrary to the tensile properties at break, the yield behavior of the composites containing fibers, severely shortened, is independent of the presence of the fibers at 23°C.
Comparative stability of arbutin in Arctostaphylos uva‐ursi by a new comprehensive stability‐indicating HPLC method
Authors: Braga Vanessa Cristina de Carvalho , Pianetti Gérson Antônio , César Isabela Costa 
Published: June 2020

AbstractIntroductionArbutin is a phenol glucoside found in high concentrations in bearberry leaves and associated with the antimicrobial activity of the plant. Hydroquinone can also be found in leaves or be formed by degradation of arbutin. Lengthy exposure to free hydroquinone is associated with induction of toxicity in different organs.ObjectiveTo develop and validate a stability‐indicating method by high‐performance liquid chromatography diode array detector (HPLC‐DAD) for simultaneous quantification of arbutin and hydroquinone in bearberry leaves and perform a comprehensive forced degradation study comparing synthetic arbutin and the arbutin in bearberry leaves.MethodsSeparation was performed using a C18 column, mobile phase with water–methanol (95:5), flow rate 1.0 mL/min and detection at 280 nm. Bearberry leaves were assayed and a forced degradation study of arbutin was performed in different conditions.ResultsThe method complied with all required validation parameters. Contents varied from 1.19 to 4.15% (w/w) of arbutin and from 0.022 to 0.604% (w/w) of hydroquinone. Synthetic arbutin was susceptible to acid hydrolysis and oxidative degradation, forming hydroquinone as the main degradation product. The same study using bearberry leaves showed that constituents of the plant matrix may act as antioxidants, reducing the oxidative degradation of arbutin, however acid hydrolysis of arbutin occurred in higher intensity.ConclusionAnalysis of bearberry leaves evidenced high variation in arbutin and hydroquinone levels, demonstrating the need for standardisation and control. The stability profiles of synthetic arbutin and the arbutin in bearberry leaves were considerably different and the results may be useful for determining the most appropriate conditions for extraction and production of bearberry‐based formulations.
Fabrication and characteristics of high‐VOC single‐crystalline Cu2ZnSnSe4 solar cells
Authors: Lloyd Michael A. , McCandless Brian E. , Birkmire Robert 
Published: June 2020

AbstractCu2ZnSnSe4 single‐crystal solar cells with open‐circuit voltages reaching 450 mV are demonstrated. The key differences in performance between high‐ and low‐voltage cells are analyzed and compared with state‐of‐the‐art thin film devices. Copper‐poor absorbers of two different compositions were evaluated as a function of surface treatment. Temperature‐dependent JV measurements were used to assess the efficacy of interface passivation. Crystals with lower copper content are shown to require more aggressive chemical treatments to achieve the maximal benefits than does their higher‐Cu counterparts. Hole concentration is confirmed via Hall characterization, with smaller densities corresponding to lower Cu concentration. In conjunction with poor lifetimes, these carrier densities are shown to limit collection at long wavelength, which reduces current in single‐crystal devices. The decrease in Cu concentration is also shown to increase the bandgap from 0.98 to 1.03 eV while maintaining the same level of subbandgap absorption. Postfabrication device annealing was shown to benefit devices with higher Cu/Zn + Sn ratios but hinder devices further deviating from stoichiometry, which is attributed to pn‐junction degradation.
On properties of probability‐based multivariate process capability indices
Authors: Khadse Kailas Govinda , Khadse Aditya Kailas 
Published: June 2020

AbstractMultivariate process capability indices (MPCIs) have been proposed to measure multivariate process capability in real‐world application over the past three decades. For the practitioner's point of view, the intention of this paper is to examine the performances and distributional properties of probability‐based MPCIs. Considering issues of construction of capability indices in multivariate setup and computation with performance, we found that probability‐based MPCIs are a proper generalization of univariate basic process capability indices (PCIs). In the beginning of this decade, computation of probability‐based indices was a difficult and time‐consuming task, but in the computer age statistics, computation of probability‐based MPCIs is simple and quick. Recent work on the performance of MPCI NMCpm and distributional properties of its estimator reasonably recommended this index, for use in practical situations. To study distributional properties of natural estimators of probability‐based MPCIs and recommended index estimator, we conducted simulation study. Though natural estimators of probability‐based indices are negatively biased, they are better with respect to mean, relative bias, mean square error. Probability‐based MPCI MCpm is better as compared with NMCpm with respect to performance and as its estimator quality. Hence, in real‐world practice, we recommend probability‐based MPCIs as a multivariate analogue of basic PCIs.
A hidden Markov model to detect regime changes in cryptoasset markets
Authors: Giudici Paolo , Abu Hashish Iman 
Published: June 2020

AbstractThe objective of this work is to understand the dynamics of cryptocurrency prices. Specifically, how prices switch between different regimes, going from “bull” to “stable” and “bear” times. For this purpose, we propose a hidden Markov model that aims at explaining the evolution of Bitcoin prices through different, unobserved states. The implementation of the proposed model includes a likelihood ratio test that allows to compare models with different states and with different covariance structures. Our empirical findings show that the time movements of Bitcoin prices across different exchange markets are well‐described by the proposed model. In particular, a parsimonious model with a diagonal covariance matrix leads to better predictions, compared with a model with a full covariance matrix.
Ferromagnetism and structural deformation in monolayer alpha lead oxide induced by N and F doping: New insights from first principles
Authors: Muhammady Shibghatullah , Noor Fatimah A. , Widita Rena , Darma Yudi 
Published: June 2020

AbstractWe study the structural, electronic, and magnetic properties of monolayer α‐PbO0.875A0.125 (A = N, F), which are calculated using first principles. As a result, N doping induces local ferromagnetism centered at the N2− site, originating from the spin‐down N 2p valence states. On the other hand, F doping induces nonmagnetism and induces ab‐plane deformation, where F− receives one electron to its nearest‐neighboring Pb1.75+ ions. N doping redshifts the bandgap of the undoped system and transforms it to be indirect, while F doping blueshifts the bandgap through the Burstein‐Moss effect. The hybridization of Pb 6p and O 2p orbitals is stronger near the A site than that of the crystal structure edge. Our result shows new insights, predicting possible experimental results for future functional device applications.
Adaptive disturbance estimation and cancelation for ships under thruster saturation
Authors: Hu Xin , Wei Xinjiang , Han Jian , Zhu Xiaodan 
Published: June 2020

SummaryThis work addresses the problem of disturbance estimation and cancelation for ships with ocean disturbances and modeling uncertainties under thruster saturation effects. The ocean disturbances are expressed as the multiple sinusoidal disturbances with unknown frequencies, amplitudes, and phases. By means of a parametric exogenous system and a canonical model with unknown disturbances being inputs, the ocean disturbances are represented as the multivariate regression model with unavailable regressors and regression parameters. An observer is employed to provide the regressor estimation, such that the disturbance estimation and cancelation are converted to the adaptive control problem. The robust control term with the adaptive technique attenuates the modeling uncertainties. The thruster saturation effects are reduced using the state vectors from the auxiliary dynamic filter to online correct the control errors. The ship disturbance cancelation controller is derived via the adaptive backstepping. The closed‐loop tracking system is guaranteed to be uniformly ultimately stable and the ship's position and heading navigate along with desired trajectories. The proposed adaptive control scheme is validated by simulations with comparisons on a 1:70 scaled model ship CyberShip II in different cases.
Polynomial filtering for nonlinear stochastic systems with state‐ and disturbance‐dependent noises
Authors: Sheng Li , Niu Yichun , Gao Ming , Zhou Donghua 
Published: June 2020

SummaryThis article is concerned with the polynomial filtering problem for a class of nonlinear stochastic systems governed by the Itô differential equation. The system under investigation involves polynomial nonlinearities, unknown‐but‐bounded disturbances, and state‐ and disturbance‐dependent noises ((x,d)‐dependent noises for short). By expanding the polynomial nonlinear functions in Taylor series around the state estimate, a new polynomial filter design method is developed with hope to reduce the conservatism of the existing results. In virtue of stochastic analysis and inequality technique, sufficient conditions in terms of parameter‐dependent linear matrix inequalities (PDLMIs) are derived to guarantee that the estimation error system is input‐to‐state stable in probability. Moreover, the desired polynomial matrix can be obtained by solving the PDLMIs via the sum‐of‐squares approach. The effectiveness and applicability of the proposed method are illustrated by two numerical examples with one concerning the permanent magnet synchronous motor.
Green Synthesis Using PEG‐400 Catalyst, Antimicrobial Activities, Cytotoxicity and In Silico Molecular Docking of New Carbazole Based on α‐Aminophosphonate
Authors: An Tran Nguyen Minh , Cuong Nguyen Van , Quang Nguyen Minh , Thanh Truong Vu , Alam Mahboob 
Published: June 2020

AbstractNew analog α–amino phosphate series with high yield through an effective and environmentally friendly protocol using the PEG‐400 catalyst via Kabachnik‐Fields has been reported. They were performed to screen antimicrobial activities by the dish diffusion method, anticancer against MCF‐7, A‐549, and HeLa human cancer cell lines by MTT assay, and carried out in silico molecular docking by Avogadro, AutoDockTools, Discovery Studio 2019 Client, and Molegro Molecular Viewer packages. The 3c and 3h displayed excellent inhibition against Candida albicans and Saccharomyces cerevisiae fungi, respectively. The molecular docking model indicated the reasonable explanations between the receptor and bioactive compounds in vitro of 3c, 3 h, and 3b. The 3c was shown as an excellent inhibitor against Candida albicans, which was a new result in vitro and in silico molecular docking model. The 3c, 3 f, and 3i pointed out excellent inhibitions against HeLa cell lines and new anticancer results of α–amino phosphate compounds. The docking studies of structures against receptors of three human cancer cell lines were conducted and recommended that the hydrogen bonds only formed from active sites of receptors to oxygen atom of the ethoxy group, nitrogen and hydrogen atoms of N−H group, oxygen atom of the P=O double bond group, and the fluorine atoms of the CF3 group in 3i for calculated docking of the receptors of bacteria, fungi, and cancer cell lines to all ligands.
Mechanistic Insight into the Turn‐Off Sensing of Nitroaromatic Compounds Employing Functionalized Polyaniline
Authors: Venkatappa Lakshmidevi , Ture Satish Ashok , Yelamaggad Channabasaveshwar V. , Narayanan Naranammalpuram Sundaram Venkata , Martínez‐Máñez Ramón , Abbaraju Venkataraman 
Published: June 2020

AbstractConducting Polymers (CPs), in recent times have contributed significantly in the detection of High Energy Materials possessing nitro functional groups through fluorescence quenching studies. Camphor sulphuric acid doped polyaniline (C‐PANI) is studied with a view to obtain easily processable PANI without π‐stacking for the detection of Picric acid(PA) and p‐nitro toluene(pNT) in trace levels. The quenching constant and limit of detection were found to be 2.236×10−6 M and 6.14×10−7 M for PA and 1.9447×10−7 M and 3.57×10−7 M for pNT, respectively showing a very good sensitivity in detection. Resonance Raman spectroscopy (RRS) showed the involvement of the bipolaronic and benzenoid group in the charge transfer complex formed between the conducting polymer and the analyte. The photoluminescence studies indicated a predominant PET mechanism. The electrochemical studies employing cyclic voltammetry gave higher band gap on comparison with absorption studies. The positive and negative shift in oxidation and reduction potential of polymer‐analyte was observed and collaborated with the fluorescence studies to understand the possible fluorescence quenching mechanism from electrochemical approach.
Synthesis and Antitumor Activity of Novel Heterocyclic Systems with Monoterpenic Skeleton Combining Dichlorocyclopropane and 1,3,4‐Thiadiazole Nucleus
Authors: Oubella Ali , Fawzi Mourad , Auhmani Aziz , Riahi Abdelkhalek , Morjani Hamid , Robert Anthony , Ait Itto Moulay Y. 
Published: June 2020

AbstractA series of C(2)‐N(4)‐disubstituted 1,3,4‐thiadiazoles bearing dichlorocyclopropane, have been prepared from (R)‐carvone 1 in a three‐step procedure. First, (R)‐carvone was treated with dichlorocarbene, generated in‐situ from chloroform using PTC technique. The resulting dichlorocyclopropane 2 was then converted into thiosemicarbazone derivatives 3 a–c before being transformed peri‐selectively and efficiently (up to 80 % yield) into their corresponding 1,3,4‐thiadiazoles (6 a–d and 7 a–c) via 1,3‐dipolar cycloaddition reaction with diarylnitrilimines 4 a–d and N‐aryl‐C‐ethoxycarbonyl‐nitrilimines 5 a–c. The structures of all the newly synthesized cyclopropanic 1,3,4‐thiadiazoles 6 a–d and 7 a–c were fully identified on the basis of their HRMS and NMR (1D & 2D) spectral data. The evaluation of compounds 2, 3 a–c, 6 a–d and 7 a–c, against HT‐1080 fibrosarcoma, breast adenocarcinoma (MCF‐7 and MDA‐MB‐231), and lung carcinoma A‐549 cells, using viability testing (MTT) showed promising antitumor activity, especially for compounds 3 a, 6 b and 6 c for which the IC50 values, against HT‐1080 fibrosarcoma, were respectively 18.92, 16.12 and 15.37 (μM).
Methyl Formate: How It Can Be Used as Formyl Group Source for Synthesis of Aldehydes via Hydroformylation?
Authors: Gorbunov Dmitry , Nenasheva Maria , Terenina Maria , Kardasheva Yulia , Maksimov Anton , Karakhanov Eduard 
Published: June 2020

AbstractFor the first time the mixture of methyl formate and water is used as an alternative syngas source for hydroformylation of unsaturated compounds in the presence of rhodium catalysts modified with phosphine ligands to obtain aldehydes. Under reaction conditions, methyl formate decomposes producing methanol and carbon monoxide. The water‐gas shift reaction (WGSR) takes place under the same conditions resulting in carbon dioxide and hydrogen generation. Influence of different parameters (temperature, ratios of reagents, type of the ligand) on the process is observed and the possibility of different olefins to transform to aldehydes with sufficient yields by this procedure is demonstrated. In this system methanol, hydrogen, and CO2 are accumulated. These components can be isolated and used as starting materials for the synthesis of methyl formate, an initial source for gas production. Thus, methyl formate acts as a “workhorse” in the system. In addition, to gain cyclic acetals tandem hydroformylation‐acetalization was performed in the methyl formate/water system for the first time.
Preparation and Kinetics of g‐C3N4/TiO2 Nanomaterials for the Photodegradation of Pyridine Under Solar‐Light Irradiation
Authors: Liu Min , Feng Tian Xue , Long Chang Yan 
Published: June 2020

AbstractAs a high‐efficient photocatalyst, g‐C3N4/TiO2 (PCN) was successfully prepared by thermal polymerization. In addition, the structure and morphological characteristics of the as‐prepared samples were investigated by XRD, BET, XPS, SEM, TEM, and UV‐vis DRS. The results revealed that in the presence of g‐C3N4, the physicochemical properties of the catalyst and the band gap of PCN decreased from 3.09 eV to 2.98 eV, clearly indicative of the enhanced photocatalytic performance relative to pure P25 or g‐C3N4 under sunlight. Furthermore, the photocatalytic properties of PCN were examined by the degradation of pyridine and other nitrogen heterocyclic pollutants under sunlight irradiation. Next, the main factors affecting the photocatalytic activity were investigated in detail, including the initial concentration of the pollutant, the mass of the photocatalyst, the initial pH of the solution, and the doping amount of g‐C3N4, as well as different free‐radical scavengers. On the other hand, the reusability of PCN demonstrated that photocatalysts exhibit outstanding photocatalytic stability after 10 cycles. Hence, high efficiency photocatalysts demonstrate potential for industrial applications such as sewage treatment.
Organization, membership and the formalization of behavioural expectations
Authors: Luhmann Niklas 
Published: June 2020

AbstractThis text is a translation of the first five chapters of Niklas Luhmann's book ‘Funktionen und Folgen formaler Organisation’ [Functions and consequences of formal organization], which originally appeared in German in 1964. In contrast to his later works, which rely crucially on the concept of communication, in this text, Luhmann applies an action‐based approach. He defines social systems as consisting of meaningfully interrelated actions that can be distinguished from their environment. Organizations are a specific type of social systems, that is, a social system that orders actions through the formalization of certain expectations. Formal expectations are those that are bound to the membership role and the acceptance of these is the condition for entry into and exit from the organization. Through the generalized member role, an organization is capable of defining highly generalized expectations. Thus, membership becomes the basis for imposing a broad range of specific yet constantly changeable expectations on members.
Trajectory mapping of human embryonic stem cell cardiogenesis reveals lineage branch points and an ISL1 progenitor-derived cardiac fibroblast lineage
Authors: Mononen Mimmi M. , Leung Chuen Yan , Xu Jiejia , Chien Kenneth R. 
Published: June 2020

Abstract
A family of multipotent heart progenitors plays a central role in the generation of diverse myogenic and nonmyogenic lineages in the heart. Cardiac progenitors in particular play a significant role in lineages involved in disease, and have also emerged to be a strong therapeutic candidate. Based on this premise, we aimed to deeply characterize the progenitor stage of cardiac differentiation at a single-cell resolution. Integrated comparison with an embryonic 5-week human heart transcriptomic dataset validated lineage identities with their late stage in vitro counterparts, highlighting the relevance of an in vitro differentiation for progenitors that are developmentally too early to be accessed in vivo. We utilized trajectory mapping to elucidate progenitor lineage branching points, which are supported by RNA velocity. Nonmyogenic populations, including cardiac fibroblast-like cells and endoderm, were found, and we identified TGFBI as a candidate marker for human cardiac fibroblasts in vivo and in vitro. Both myogenic and nonmyogenic populations express ISL1, and its loss redirected myogenic progenitors into a neural-like fate. Our study provides important insights into processes during early heart development.
Field measurements and wind tunnel experimental investigations of wind effects on Guangzhou West Tower
Authors: Xie Zhuangning , Liu Chunlei , Yu Xianfeng 
Published: June 2020

SummaryThe wind‐induced acceleration responses at the top of the Guangzhou West Tower (GZWT; 432 m) and the wind speed and direction at the top of Guangzhou Tower (532 m), which is located across the GZWT, were measured during the passage of Typhoon Mangkhut. The two buildings are separated by a river. The variation characteristics of the first two natural frequencies and damping ratios of the GZWT under strong vibrations are obtained by using random decrement technique (RDT) and modified Bayesian spectral density approach (MBSDA). Finally, field measurements of the maximum peak accelerations are compared with wind tunnel test results. The damping ratios identified by MBSDA are found to be greater than the results obtained by RDT. The natural frequencies decrease with increasing maximum acceleration of the corresponding acceleration segment. Besides, they decrease firstly and then increase with time elapses, reaching a minimum value at the maximum mean wind speed. The damping ratios are completely discrete, and no obvious linear correlation exists between the damping ratios and maximum acceleration of the corresponding acceleration segment. The peak accelerations at the top of the GZWT obtained from wind tunnel experiment agree well with that of full‐scale measurements.