bluuebunny/crossref_metadata_2025 huggingface dataset:
New Fullerene Derivative as an n‐Type Material for Highly Efficient, Flexible Perovskite Solar Cells of a p‐i‐n Configuration
Authors: Ahmad Taimoor , Wilk Barbara , Radicchi Eros , Fuentes Pineda Rosinda , Spinelli Pierpaolo , Herterich Jan , Castriotta Luigi Angelo , Dasgupta Shyantan , Mosconi Edoardo , De Angelis Filippo , Kohlstädt Markus , Würfel Uli , Di Carlo Aldo , Wojciechowski Konrad
Published: September 2020

Metal halide perovskites have raised huge excitement in the field of emerging photovoltaic technologies. The possibility of fabricating perovskite solar cells (PSCs) on lightweight, flexible substrates, with facile processing methods, provides very attractive commercial possibilities. Nevertheless, efficiency values for flexible devices reported in the literature typically fall short in comparison to rigid, glass‐based architectures. Here, a solution‐processable fullerene derivative, [6,6]‐phenyl‐C61 butyric acid n‐hexyl ester (PCBC6), is reported as a highly efficient alternative to the commonly used n‐type materials in perovskite solar cells. The cells with the PCBC6 layer deliver a power conversion efficiency of 18.4%, fabricated on a polymer foil, with an active area of 1 cm2. Compared to the phenyl‐C61‐butyric acid methyl ester benchmark, significantly enhanced photovoltaic performance is obtained, which is primarily attributed to the improved layer morphology. It results in a better charge extraction and reduced nonradiative recombination at the perovskite/electron transporting material interface. Solution‐processed PCBC6 films are uniform, smooth and displayed conformal capping of perovskite layer. Additionally, a scalable processing of PCBC6 layers is demonstrated with an ink‐jet printing technique, producing flexible PSCs with efficiencies exceeding 17%, which highlights the prospects of using this material in an industrial process.
A New Strategy for Large Dynamic Piezoelectric Responses in Lead‐Free Ferroelectrics: The Relaxor/Morphotropic Phase Boundary Crossover
Authors: Zhang Le , Wang Haoyu , Wang Dong , Guo Mengyao , Lou Xiaojie , Wang Danyang
Published: September 2020

One of the key problems in the existing lead‐free piezoelectrics lies in how to further boost their dynamic piezoelectric responses, i.e., electrostrain and dynamic piezoelectric constants, in an effective and facile manner, making them comparable to those of widely used lead‐based counterparts. In this work, a new strategy is developed to largely improve the dynamic piezoelectric properties of lead‐free ferroelectrics using phase field simulations by combining the relaxor/ferroelectric crossover rendering potentially reversible electrostrain and the morphotropic phase boundary (MPB) providing easy paths of ferroelectric polarization rotations. Following the guidance of simulation results, Mn‐doped (Bi0.5Na0.5)TiO3–BaTiO3 lead‐free piezoelectric ceramics with relaxor/MPB crossover are synthesized. A large reversible electrostrain (Smax) of 0.55% with a promising piezoelectric constant d33* (Smax/Emax) of 917 pm V–1 at the designed relaxor/MPB crossover is obtained, outperforming almost all practical lead‐free counterparts when taking both electrostrain and dynamic piezoelectric constants into consideration. The strategy of utilizing relaxor/MPB crossover provides a new route for enhancing the dynamic piezoelectric responses in lead‐free ferroelectric perovskites.
A Hierarchical Structured Ultrafine Fiber Device for Preventing Postoperative Recurrence and Metastasis of Breast Cancer
Authors: Li Xilin , Xu Funeng , He Yang , Li Yan , Hou Jianwen , Yang Guang , Zhou Shaobing
Published: September 2020

The high incidence of postoperative recurrence and metastasis has a serious effect on survival in breast cancer patients. Moreover, it is still a great challenge to prevent the postoperative recurrence and metastasis through traditional implantable devices due to their inability to control multiple drug release. Herein, an implantable hierarchical structured ultrafine fiber device with a time‐programmed drug release function for the local postoperative adjuvant chemotherapy of breast cancer is developed. The structure is obtained through a co‐axial electrospinning technology by the formation of the periodically arranged chambers inside a fiber matrix. The Doxorubicin hydrochloride in these chambers is released rapidly, killing the residual tumor cells to prevent tumor recurrence; while the matrix metalloproteinases‐2 (MMP‐2) inhibitor disulfiram in the fiber matrix is released in a sustained manner, inhibiting tumor invasion to prevent its metastasis. The fiber device implanted in tumor‐bearing mice after a surgical tumor reduction displays excellent therapeutic efficacy by preventing both recurrence and metastasis. The mechanism investigation of tumor invasion through the type‐II collagen immunofluorescence analysis reveals that the decrease of the activity of MMP‐2 plays a key role in this process.
Tadpole‐Shaped Catalytic Janus Microrotors Enabled by Facile and Controllable Growth of Silver Nanotails
Authors: Lv Xianglong , Xiao Zuyao , Zhou Chao , Wang Yong , Duan Shifang , Chen Jingyuan , Duan Wendi , Ma Xing , Wang Wei
Published: September 2020

Microrotors are an indispensable component in micromachines, yet their usefulness has been limited by a lack of simple, inexpensive, and controlled fabrication technique that yields microrotors of controlled shapes in large quantities. To address this challenge, the chemical synthesis, characterization, and activation of tadpole‐shaped catalytic microrotors that consist of a spherical, platinum (Pt)‐coated head and a silver (Ag) nano‐tail of tunable lengths are reported herein. Importantly, this tail spontaneously grows on Pt in an aqueous solution of Ag+ and hydrogen peroxide (H2O2), at a speed of ≈100 nm s−1, preferably along the Ag (111) plane. The growth of Ag nanowires is attributed to an electrochemical reaction occurring on a tapered Pt cap, a mechanism corroborated by control experiments with photo‐active titania microspheres, which introduce the additional advantage of light‐controlled growth. The presence of a long Ag nano‐tail on a tadpole‐shaped microrotor breaks its symmetry and induces rotation in H2O2, and its structure‐dependent dynamics is quantitatively studied and supported by numerical simulation. The chemical synthesis of microrotors with Ag nano‐tails will introduce new designs of micromachines of controlled dynamics, as well as functional materials and devices where mild, controllable, and facile growth of Ag nanostructures is desired.
Perfect Absorption in a Disordered Medium with Programmable Meta‐Atom Inclusions
Authors: F. Imani Mohammadreza , Smith David R. , del Hougne Philipp
Published: September 2020

Achieving the very special condition of perfect absorption (PA) in a complex scattering enclosure promises to enable a wealth of applications in secure communication, precision sensing, wireless power transfer, analog signal processing, and random lasing. Consequently, a lot of recent research effort is dedicated to proposing wave‐front shaping protocols to implement coherent PA in complex scattering environments with tunable localized absorption as well as a tunable excitation frequency. Here, the conceptually different route of solely tweaking the randomness of the complex scattering environment in order to achieve PA is proposed. An experimental proof‐of‐concept in the microwave domain is provided where the randomness of a 3D chaotic cavity is tuned with programmable meta‐atom inclusions. The achievability and extreme sensitivity of the PA condition are systematically investigated. The presented technique can impose a PA condition at over hundred distinct frequencies within a small frequency band, enabling the proposal and experimental demonstration of a concrete practical application: receiver‐powered secure wireless communication in a complex scattering enclosure. The presented fundamentally new perspective on PA applies to all types of wave phenomena; the experimental results foreshadow the large potential of this novel tool for minute wave control in sensing, communication, and energy transfer.
Probing the Growth of Organic Molecular Films Embedded between Cobalt and Iron Electrodes: Ferromagnetic Nuclear Resonance Approach
Authors: Avedissian Garen , Arabski Jacek , Wytko Jennifer A. , Weiss Jean , Meny Christian
Published: September 2020

Physical properties of magnetic nanostructures and devices strongly depend on the morphological characteristics of their various components. This is especially true and becomes particularly complex in hybrid nanostructures, where soft organic molecules are at the vicinity of ferromagnetic metallic films. The supramolecular architecture of molecular films embedded between Fe and Co layers is investigated by ferromagnetic nuclear resonance (FNR). With such sample architecture, the presence of pin holes in the organic layers is detected by FNR contributions in a specific spectral range. The methodology that is developed allows the probing of the continuity and the packing of zinc tetraphenyl porphyrin (ZnTPP) molecular films between the Co and Fe films. The experimental results suggest that, regardless of the nature of the ferromagnetic underlayer, at least 15 monolayers of ZnTPP are necessary to form continuous and pin‐hole free molecular films. In addition, quantitative analyses show that ZnTPP layers exhibit distinct morphologies that are dependent on the nature of the ferromagnetic metallic underlayer.
Self‐Assembled Perovskite Nanowire Clusters for High Luminance Red Light‐Emitting Diodes
Authors: Bi Chenghao , Hu Jingcong , Yao Zhiwei , Lu Yue , Binks David , Sui Manling , Tian Jianjun
Published: September 2020

Bright red emission (620–650 nm) from perovskite light‐emitting diodes (PeLEDs) is usually achieved via a composition including both bromine and iodine anions, which results in poor performance and stability due to phase separation under operating conditions. Here a large‐scale ligand‐assisted reprecipitation method is devised with nonpolar solvent that enables the fabrication of CsPbI3 nanowire clusters, emitting at 600 nm. The blue‐shift of this emission relative to that of bulk CsPbI3 (≈700 nm) is attributed to quantum confinement in nanowires. The growth of the nanowires is along the [011] crystal direction and is vacancy driven, resulting in the healing of surface defects and thereby a high photoluminescence quantum yield of 91%. The clusters with ultralow trap density show remarkable structural and environmental stability. PeLEDs based on these clusters exhibit an external quantum efficiency of 6.2% with Commission Internationale de l'Eclairage coordinates of (0.66, 0.34), and record luminance of 13 644 cd m−2 of red electroluminescence. The half‐lifetime under an accelerated stability test is 13.5 min for an unencapsulated device in ambient conditions operating at an initial luminance of 11 500 cd m−2, which corresponds to an estimated half‐lifetime of 694 h at 100 cd m−2 based on acceleration factor obtained by experimental testing.
Electrical Dynamic Switching of Magnetic Plasmon Resonance Based on Selective Lithium Deposition
Authors: Jin Yan , Liang Jie , Wu Shan , Zhang Ye , Zhou Lin , Wang Qianjin , Liu Hui , Zhu Jia
Published: September 2020

Active plasmonic nanostructures have garnered considerable interest in physics, chemistry, and material science due to the dynamically switchable capability of plasmonic responses. Here, the first electrically dynamic control of magnetic plasmon resonance (MPR) through structure transformation by selective deposition of lithium on a metal–insulator–metal (MIM) structure is reported. Distinct optical switching between MPR and surface plasmon polariton (SPP) excitations can be enabled by applying a proper electrical current to the electrochemical cell. Furthermore, the structure transformation through lithium metal deposition indicates the reconfigurable MPR excitation in a full cycling of the charging and discharging process. The results may shed light on electrically compatible self‐powered active plasmonics as well as nondestructive optical sensing for electrochemical evolution.
Nanometer‐Scale Uniform Conductance Switching in Molecular Memristors
Authors: Goswami Sreetosh , Deb Debalina , Tempez Agnès , Chaigneau Marc , Rath Santi Prasad , Lal Manohar , Ariando  , Williams R. Stanley , Goswami Sreebrata , Venkatesan Thirumalai
Published: September 2020

One common challenge highlighted in almost every review article on organic resistive memory is the lack of areal switching uniformity. This, in fact, is a puzzle because a molecular switching mechanism should ideally be isotropic and produce homogeneous current switching free from electroforming. Such a demonstration, however, remains elusive to date. The reports attempting to characterize a nanoscopic picture of switching in molecular films show random current spikes, just opposite to the expectation. Here, this longstanding conundrum is resolved by demonstrating 100% spatially homogeneous current switching (driven by molecular redox) in memristors based on Ru‐complexes of azo‐aromatic ligands. Through a concurrent nanoscopic spatial mapping using conductive atomic force microscopy and in operando tip‐enhanced Raman spectroscopy (both with resolution <7 nm), it is shown that molecular switching in the films is uniform from hundreds of micrometers down to the nanoscale and that conductance value exactly correlates with spectroscopically determined molecular redox states. This provides a deterministic molecular route to obtain spatially homogeneous, forming‐free switching that can conceivably overcome the chronic problems of robustness, consistency, reproducibility, and scalability in organic memristors.
Space‐Confined Fabrication of MoS2@Carbon Tubes with Semienclosed Architecture Achieving Superior Cycling Capability for Sodium Ion Storage
Authors: Zhang Yuan , Liu Wei , Wang Tianqi , Du Yongxu , Cui Yongpeng , Liu Shuang , Wang Huanlei , Liu Shuai , Chen Ming , Zhou Junan
Published: September 2020

High rate and good cycling capability are always difficult for sodium ion anode materials owing to the unstable electrode structure induced by reversibly intercalation of large‐sized sodium ions. In this paper, based on the unique nanotube arrays of crab shells, a novel space‐confined growth of MoS2 nanosheets in carbon nanotubes is reported to fabricate MoS2@carbon nanotube (MoS2@CT) with a semienclosed architecture. Due to the space‐confined effect, MoS2 sheets are nanosized with poor stacking feature, which are anchored on the inner surface of carbon tubes. The semienclosed architecture built of carbon nanotubes and abundant MoS2 nanosheets enhances the stability and integrity of the electrode structure during cycles. Thereby, the coupling effect of stable structure and MoS2 with fast kinetics achieves a comprehensive performance improvement of the MoS2@CT anode materials. Particularly for cycling capability, it delivers a capacity of 170 mAh g−1 after 10 000 cycles at a high current density of 10 A g−1, which is comparable for most previously reported cases. The assembled Na‐ion hybrid supercapacitors device delivers a high energy density of 82 Wh kg−1 at a power density of 2000 W kg−1 after 5000 cycles with an 89% retention.
Gold Nanoparticles Functionalized with Fullerene Derivative as an Effective Interface Layer for Improving the Efficiency and Stability of Planar Perovskite Solar Cells
Authors: Chavan Rohit D. , Prochowicz Daniel , Bończak Bartłomiej , Tavakoli Mohammad Mahdi , Yadav Pankaj , Fiałkowski Marcin , Hong Chang Kook
Published: September 2020

Titanium dioxide (TiO2) is an extensively used electron transporting layer (ETL) in n–i–p perovskite solar cells (PSCs). Although, TiO2 ETL experiences the high surface defect together with low electron extraction ability, which causes severe energy loss and poor stability in the PSC. In this study, a new intermediate layer consisting of gold nanoparticles functionalized with fully conjugated fullerene C60 derivative (C60‐BCT@Au NPs) that enhances the interfacial contact at ETL/perovskite interface leading to a perovskite film with improved crystallinity and morphology is reported. Moreover, the studies demonstrate that the interface modification of the TiO2 ETL with C60‐BCT@Au NPs substantially improves the charge extraction efficiency from the perovskite layer and suppresses charge recombination processes. Consequently, the resulting device yields a champion efficiency of 19.08% as well as devaluation in hysteresis. In addition, the unencapsulated PSCs with c‐TiO2/C60‐BCT@Au NPs ETL retain 83% and 90% of their original PCEs after 500 h storage in air and exposure to continuous UV illumination for 200 h, respectively. This study provides an effective method to address the electron transporting issues between perovskite and c‐TiO2 ETL for developing stable and efficient PSCs.
Biocompatible and Highly Stretchable PVA/AgNWs Hydrogel Strain Sensors for Human Motion Detection
Authors: Azadi Shohreh , Peng Shuhua , Moshizi Sajad A. , Asadnia Mohsen , Xu Jiangtao , Park Inkyu , Wang Chun H. , Wu Shuying
Published: September 2020

Hydrogel‐based strain sensors have attracted considerable interest for applications such as skin‐like electronics for human motion detection, soft robotics, and human–machine interfaces. However, fabrication of hydrogel strain sensors with desirable mechanical and piezoresistive properties is still challenging. Herein, a biocompatible hydrogel sensor is presented, which is made of polyvinyl alcohol (PVA) nanocomposite with high stretchability up to 500% strain, high mechanical strength of 900 kPa, and electrical conductivity (1.85 S m‐1) comparable to human skin. The hydrogel sensors demonstrate excellent linearity in the whole detection range and great durability under cyclic loading with low hysteresis of 7%. These excellent properties are believed to be contributed by a new bilayer structural design, i.e., a thin, conductive hybrid layer of PVA/silver nanowires (AgNWs) deposited on a pure strong PVA substrate. PVA solution of high concentration is used to fabricate the substrate while the top layer consists of dilute PVA solution so that high content of AgNWs can be dispersed to achieve high electrical conductivity. Together with a rapid response time (0.32 s) and biocompatibility, this new sensor offers great potential as a wearable sensor for epidermal sensing applications, e.g., detecting human joint and muscle movements.
Unraveling Reversible Quenching Processes of O2, N2, Ar, and H2O in Metal Halide Perovskites at Moderate Photon Flux Densities
Authors: Nandayapa Edgar R. , Hirselandt Katrin , Boeffel Christine , Unger Eva L. , List‐Kratochvil Emil J. W.
Published: September 2020

Metal halide perovskites (MHP), as used in photovoltaic (PV) applications, show a rich photophysics in inert and ambient atmosphere. The presence of atmospheric molecules leads to processes that enhance as well as reduce their photoluminescence (PL) emission. Various phenomena are previously described for a wide variety of gas molecules and different classes of MHP, with a particular interest on the long‐term stability for PV applications. However, reversible PL quenching (PLQ) processes, which may be regarded equally important for the performance of PV and other optoelectronic applications, are neglected in other studies. This holds true for O2 and H2O, but especially for low‐reactive gases such as nitrogen and argon. Using low excitation densities, it is shown that noticeable—and reversible—PLQ, in addition to PL enhancements, can already be observed for O2, N2, and Ar as well as for H2O at low concentrations of 1 mbar. The nature and origin of the quenching processes are further elucidated by applying the Stern–Volmer analysis, also employed to determine whether static and dynamic PLQ processes happen for the different quenching gases. The strongest static PLQ is found for O2 and H2O. MHPs in N2 and Ar atmospheres display a moderate PLQ effect.
Photothermally Induced Transparency in Mode‐Cascaded Microcavity
Authors: Sun Yang , Liu Xiao-Fei , Wang Tie-Jun , Gao Yong-Pan
Published: September 2020

Controllable optical elements play an important role in both classical and quantum devices, making it essential to achieve controllable light transmission in a high‐precision whispering gallery mode dielectric cavity. Herein, transmission control in a dielectric microcavity with the photothermal effect is investigated. The photothermal effect introduces a thermal disturbance in a dynamical process, whose interference with the original transmission leads to the emergence of a transparent window. To obtain and regulate the transparent window, the amplitude and frequency of the eigenfrequency oscillation in the optical mode are tuned, which can be achieved by modulating the power of the pump beam. Dynamical photothermally induced transparency in a mode‐cascaded microcavity is important for exploring novel physical properties in cavity‐based all‐optical control.
Nitrogen forms in runoff export from St. Augustinegrass
Authors: Fontanier Charles H. , Aitkenhead‐Peterson Jacqueline A. , Wherley Benjamin G. , Ojeda Nadezda , White Richard H. , Thomas James C. , Dwyer Phil
Published: September 2020

Nitrogen exports from landscapes can contribute to the eutrophication of surface waters. The most common form of N studied in prior runoff research has been nitrate, although ammoniacal and organic forms of N are also considered important causes of eutrophication. The relative abundance of each N form in runoff from turfgrasses has not been widely reported. The objective of this study was to quantify dissolved inorganic N (DIN) and dissolved organic N (DON) exports in runoff from St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] turf over a 2‐yr period in College Station, TX. Treatments were arranged as a randomized complete block design having eight combinations of irrigation (100, 75, or 50% of estimated turfgrass water requirements) and fertility level (0, 88, and 176 kg N ha−1 yr−1). Runoff from 31 rainfall events and one excess irrigation event were used to estimate annual and seasonal DIN and DON exports. Nitrate‐N concentration was typically below 5 mg L−1, but peaks in excess of 20 mg L−1 were measured during late winter in one year. Aside from this atypical peak, the largest portion of total dissolved N (TDN) was DON, whereas NH4–N was typically the smallest portion. Increasing fertilizer rates typically amplified each form of N in runoff, but NO3–N was the most responsive to N rate, with corresponding reductions in the DON/TDN ratio and increases in the nitrate/ammonium ratio. Nitrate‐N may be the best indicator for fate of anthropogenic N inputs, but studies focusing only on NO3–N are likely underreporting N exports.
Networks of materials: Construction and structural analysis
Authors: Veremyev Alexander , Liyanage Laalitha , Fornari Marco , Boginski Vladimir , Curtarolo Stefano , Butenko Sergiy , Buongiorno Nardelli Marco
Published: September 2020

Modeling and analysis of the materials universe is an emerging area of research with many important applications in materials science. The main goal is to create a map of materials which allows not only to visualize and navigate the materials space, but also reveal complex relationships and “connections” among materials and potentially find clusters of materials with similar properties. In this paper, we consider the problem of mapping and exploring the materials universe using network science tools and concepts. The networks are based on the open‐source materials data repository AFLOW.org where each material is represented as a node, and each pair of nodes is connected by a link if the respective materials exhibit a high level of similarity between their Density of States (DOS) functions. We discuss the importance of similarity measure selection, investigate basic structural properties of the resulting networks, and demonstrate advantages and limitations of the proposed approaches. Materials networks, similarity measures, DOS function, materials informatics, network analysis, clique.
Demand‐based optimization of a chlorobenzene process with high‐fidelity and surrogate reactor models under trust region strategies
Authors: Yoshio Noriyuki , Biegler Lorenz T.
Published: September 2020

This work demonstrates the optimization of the industrial scale chlorobenzene process, which continuously produces multiple products and includes a multiphase reaction with bubble column reactors (BCRs). The trust region filter (TRF) method is applied to carry out the demand‐based optimization of large chlorobenzene process with high‐fidelity BCR models. The TRF method uses surrogate models that substitute the high‐fidelity BCR models in the process model, and avoids the direct implementation of high‐fidelity models, which leads to a large and intractable optimization problem. The surrogate models are constructed based on basis functions that apply first order corrections from the gradients of high‐fidelity models. Different basis functions, CSTR and linear models, are studied in this work. As a result, the usage of CSTR models for the basis function leads to fewer function evaluations of the high‐fidelity model because CSTR model is a reasonable approximation of the high‐fidelity models and an initial guess of the optimization problem. Also, the TRF with surrogate models successfully provides an optimal solution of the high‐fidelity process model with few iterations and function evaluations of the high‐fidelity model itself. From the comparison with a low‐fidelity CSTR model, the solution with the TRF presents more accurate results. The surrogate approaches also make a smooth transition from low‐ to high‐fidelity models in process development. We apply this approach to a demand‐based optimization that integrates nontrivial business options, including optimal shortage of customer demands for profitable operation.
Heat exchanger network synthesis with detailed exchanger designs—2. Hybrid optimization strategy for synthesis of heat exchanger networks
Authors: Kazi Saif R. , Short Michael , Isafiade Adeniyi J. , Biegler Lorenz T.
Published: September 2020

We propose a new strategy to synthesize heat exchanger networks with detailed designs of individual heat exchangers. The proposed strategy uses a multistep approach by first obtaining a heat exchanger network topology through solving a modified version of the mixed integer nonlinear programming (MINLP) stage‐wise superstructure of Yee and Grossmann, which includes a smoothed LMTD approximation and pressure drops. In a second nonlinear programming (NLP) suboptimization step, we allow for nonisothermal mixing to solve problems with or without exchanger bypasses. The selected heat exchangers along with the mass and energy balances obtained are then used to design the network with detailed exchanger designs through solving a sequence of NLPs for individual heat exchanger designs. The NLPs are based on the detailed discretized optimization models of Kazi et al., which solve quickly and reliably to obtain heat exchangers based on rigorous, first‐principles derived coupled differential equations. These models solve a differential algebraic equation system and do not rely on usual assumptions associated with other heuristic‐based exchanger design methods, such as log mean temperature difference and FT correction factors. These detailed exchanger designs are then used to update the network optimization model through sets of correction factors on heat exchanger area, number of shells, heat transfer coefficients, and pressure drops of each exchanger design, in a method based on that of Short et al. The method solves reliably, guaranteeing feasible exchangers for every potential network generated by the shortcut models, through validation with rigorous heat exchanger models at every iteration. In addition, the method does not increase the nonlinearity of the MINLP model, nor does it require any manual intervention or initialization from the user. Three examples are solved and the results are compared to those obtained in the literature.
Optimal design of water pipeline networks for the development of shale gas resources
Authors: Cafaro Diego C. , Grossmann Ignacio
Published: September 2020

One of the major concerns in shale gas production is water management. Millions of gallons of water are injected to fracture each well and a significant amount returns to the surface as flowback. Operators are increasingly reusing flowback to reduce freshwater consumption and impaired water disposal. Because of this, networks of water pipelines in U.S. shales are growing fast. This work is aimed at addressing the optimal planning of shale gas operations in multiple wellpads together with the design of water distribution networks (WDN). We propose a multiperiod mixed‐integer linear programming model to solve the challenging stay‐or‐mobilize trade‐off. The proposed model permits to schedule operations at a detailed level, accounting for the WDN required to maximize the reuse of impaired water. We present illustrative examples involving up to 20 pads, 4 frac‐crews, and 100 wells developed over 1 year, showing that the design of the WDN can be effectively optimized.
A Facile C‐H Insertion Strategy using Combination of HFIP and Isocyanides: Metal‐Free Access to Azole Derivatives
Authors: Gujjarappa Raghuram , Vodnala Nagaraju , Reddy Velma Ganga , Malakar Chandi C.
Published: September 2020

An efficient metal‐free approach has been devised towards the synthesis of azoles via C−H insertion protocol. Various isocyanides were examined as effective C1‐synthons. The HFIP plays crucial role as hydrogen source and promoter of the reaction in order to reveal the maximum efficacies to accomplish the transformation in high yields of the products with excellent functional group tolerance. The control experiment affirmed 83% of deuterium incorporation, when the reaction was performed using HFIP‐d2.
Efficacy of the exhalation delivery system with fluticasone in patients who remain symptomatic on standard nasal steroid sprays
Authors: Senior Brent A. , Schlosser Rodney J. , Bosso John , Soler Zachary M.
Published: September 2020

Background

Standard nasal steroid sprays are often first‐line treatment for chronic rhinosinusitis (CRS), but many patients remain symptomatic despite their use. The exhalation delivery system with fluticasone (EDS‐FLU) has been shown to be efficacious in mixed populations of symptomatic patients, but the question remains whether benefits would be similar in those already on traditional steroid sprays. The goal of this study was to compare EDS‐FLU treatment outcomes in patients who have previously failed nasal steroids.

Methods

Using pooled data from the NAVIGATE I and II trials, EDS‐FLU efficacy was compared in the subgroup treated with a conventional nasal steroid at trial entry (mean duration, ≈3 years) to efficacy in the overall study population. Sensitivity analyses were performed for more restrictive definitions of the subgroup changing from prior standard nasal steroids.

Results

Of 482 total subjects, 218 (45.2%) reported using standard nasal steroid sprays at entry (mean duration, 1051 days). Across multiple outcome measures, improvements for “switchers” receiving EDS‐FLU (least squares mean change from baseline vs EDS plus placebo) were comparable with improvements in the overall population. For EDS‐FLU 372 μg, comparable improvements were observed in congestion (−0.73 vs −0.62), rhinorrhea (−0.71 vs −0.57), facial pain/pressure (−0.48 vs −0.41), and sense of smell (−0.35 vs −0.30) at week 4 and 22‐item Sino‐Nasal Outcome Test (−21.01 vs −20.52), Patient Global Impression of Change, and other outcomes at week 16. Results for EDS‐FLU 186 μg were similar.

Conclusion

EDS‐FLU comparably improves symptoms, irrespective of whether patients are symptomatic while using conventional nasal steroids before treatment.
Interfacial Microcompartmentalization by Kinetic Control of Selective Interfacial Accumulation
Authors: Liu Qian , Yuan Zhenyu , Zhao Meng , Huisman Max , Drewes Gido , Piskorz Tomasz , Mytnyk Serhii , Koper Ger J. M. , Mendes Eduardo , van Esch Jan H.
Published: September 2020

Reported here is a 2D, interfacial microcompartmentalization strategy governed by 3D phase separation. In aqueous polyethylene glycol (PEG) solutions doped with biotinylated polymers, the polymers spontaneously accumulate in the interfacial layer between the oil‐surfactant‐water interface and the adjacent polymer phase. In aqueous two‐phase systems, these polymers first accumulated in the interfacial layer separating two polymer solutions and then selectively migrated to the oil‐PEG interfacial layer. By using polymers with varying photopolymerizable groups and crosslinking rates, kinetic control and capture of spatial organisation in a variety of compartmentalized macroscopic structures, without the need of creating barrier layers, was achieved. This selective interfacial accumulation provides an extension of 3D phase separation towards synthetic compartmentalization, and is also relevant for understanding intracellular organisation.
Strongσ‐Hole Activation on Icosahedral Carborane Derivatives for a Directional Halide Recognition
Authors: Beau Maxime , Lee Sunhee , Kim Sooyeon , Han Won‐Sik , Jeannin Olivier , Fourmigué Marc , Aubert Emmanuel , Espinosa Enrique , Jeon Ie‐Rang
Published: September 2020

Crystal engineering based onσ‐hole interactions is an emerging approach for realization of new materials with higher complexity. Neutral inorganic clusters derived from 1,2‐dicarba‐closo‐dodecaborane, substituted with ‐SeMe, ‐TeMe, and ‐I moieties on both skeletal carbon vertices are experimentally demonstrated herein as outstanding chalcogen‐ and halogen‐bond donors. In particular, these new molecules strongly interact with halide anions in the solid‐state. The halide ions are coordinated by one or two donor groups (μ1‐ and μ2‐coordinations), to stabilize a discrete monomer or dimer motifs to 1D supramolecular zig‐zag chains. Crucially, the observed chalcogen bond and halogen bond interactions feature remarkably short distances and high directionality. Electrostatic potential calculations further demonstrate the efficiency of the carborane derivatives, withVs,maxbeing similar or even superior to that of reference organic halogen‐bond donors, such as iodopentafluorobenzene.
DNA/bovine serum albumin binding and cytotoxicity of transition metal ternary complexes based on sulfamethazine and bromazepam drugs
Authors: Mansour Ahmed M. , Abdel‐Ghani Nour T. , Ragab Mona S.
Published: September 2020

Similar to the antibiotic mixing strategies, which depend on reducing the worth of diffusion of the resistant bacteria to new host, in this contribution, we explicit new mixed‐ligand complexes of the type [M(SMZ)2(BZM)] (M = Co(II), Ni(II) and Cu(II)) based on two drugs: sulfamethazine (SMZ) and bromazepam (BZM). The novelty aspect of the present work relies on combining two drugs in a single molecule via the synthesis of the ternary complexes. The ternary complexes were characterized by spectroscopic and analytical tools with the aid of the quantum chemical calculations. Copper(II) complex has the highest DNA intrinsic binding constant (2.20 × 105 M−1), induces extensively DNA cleavage compared to the other complexes, and exhibits the highest cytotoxicity (IC50 = 0.67 μM) against human liver cancer cell line (HepG2). Exciting, Cu(II) compound exhibits no toxicity to the nonmalignant human foetal lung fibroblast (WI‐38). Alternatively, the low cytotoxicity of the Co(II) complex correlates well with the high affinity of the compound to human serum albumin (Kb = 4.58 × 105) compared to 1.93 × 105 and 2.14 × 105 M−1 for Ni (II) and Cu (II) complexes, respectively.
Fabrication and analysis of palmitic acid–decanoic acid@Ce–Eu/TiO2 composite as a building material for regulating indoor environment
Authors: Zong Zhifang , Chen Depeng , Zhao Chunxiao , Dong Wei , Tang Gang , Zhang Hao , Zhu Xiujuan
Published: September 2020

Novel palmitic acid–decanoic acid@Ce–Eu/TiO2 (PA–DA@Ce–Eu/TiO2) microspheres with high photocatalysis–thermal–humidity collaborative performance were prepared via a two‐step method. Ce and Eu were used for codoping to modify the TiO2 hollow microspheres to enhance the photocatalytic properties. Furthermore, a eutectic phase change material (PA–DA) was combined with Ce–Eu/TiO2 hollow microspheres to prepare PA–DA@Ce–Eu/TiO2 microspheres. X‐ray diffraction and UV–VIS spectral analyses proved that Ce–Eu codoping enhanced the photocatalytic properties of the PA–DA@Ce–Eu/TiO2 microspheres under solar light; the degradation rate to gaseous formaldehyde at low concentrations reached 54.98% after 5 h. The pore structure, particle size distribution, microstructure, and thermostability of the PA–DA@Ce–Eu/TiO2 microspheres were determined using N2 adsorption isotherms, laser scattering particle size distribution analysis, scanning electron microscopy, and thermogravimetric analysis, respectively. The results showed that the Ce–Eu/TiO2 microspheres had a typical mesoporous structure, concentrated particle size distribution, and rough surface. The porous structure of the PA–DA@Ce–Eu/TiO2 microspheres was conducive to adsorb/desorb moisture, which was recorded to be 0.0575 g/g at 43.16–75.29% relative humidity. The differential scanning calorimeter analysis showed that the phase transition temperature of the PA–DA@Ce–Eu/TiO2 microspheres was 20–22°C and that the PA–DA@Ce–Eu/TiO2 microspheres were stable at 35°C. After 300 thermal cycles, the heat storage capacity of the PA–DA@Ce–Eu/TiO2 microspheres decreased by only 5%. Thus, we concluded that the PA–DA@Ce–Eu/TiO2 microspheres can purify air and control indoor thermal and humidity environments simultaneously and hence can be used as functional building materials to adjust the indoor environment.
Silica‐poly(2‐ethyl‐2‐oxazoline) hairy nanoparticle with high organic content as a material for anticorrosion nanocomposite coatings
Authors: Khodabakhshi Javad , Mahdavi Hossein
Published: September 2020

A simple, versatile, and effective method for synthesizing a hydrophilic silica nanoparticle with high organic content and strong anti‐corrosion effect reported. Cationic polymerization of 2‐ethyl‐2‐oxazoline and its orientation around a silica nanoparticle, which is formed in‐situ during the reaction, results a hairy nanoparticle with high organic content. Due to the high molar ratio of active atoms in polymer chains, the corrosion protection performance of nanocomposite coatings against corrosive medium greatly enhanced relative to blank neat coating sample. At low concentrations of hairy nanoparticles in coating, the corrosion current density dramatically reduced and corrosion potential displaced towards the anodic potentials, which mean the anodic inhibition mechanisms, suppressed the corrosion reactions. In addition, the organic and smooth surface of hairy nanoparticles is highly compatible with coating matrix, and no phase separation or cracking occurs at the interface of nanoparticle/matrix.
Nonlinear stress relaxation of filled rubber compounds: A new theoretical model and experimental investigation
Authors: Ghoreishy Mir Hamid Reza , Abbassi‐Sourki Foroud
Published: September 2020

A new nonlinear hyper‐viscoelastic constitutive model was developed to describe the mechanical behavior of filled rubbers. It consists of a conventional strain energy density function like Arruda‐Boyce weighted by a four‐parameter decay relationship, designed as a function of time and the deviatoric part of the first invariant of the left Cauchy‐Green deformation tensor. It was implemented in Abaqus code as a user subroutine. A SBR/BR rubber compound filled with carbon black was selected as the test material. The material parameters were determined by calibrating the data from the uniaxial stress–strain tensile, volumetric, and stress relaxation tests using an optimization loop designed in Isight program. To validate the proposed model, a series of simulations were performed on two rubber strips and a rubber cylinder under extensive and compressive loads, respectively. Comparison with their corresponding experimental data confirmed the accuracy, and validity of the proposed model and approach.
Superior electrical, mechanical and viscoelastic properties of CNTs coated carbon textile reinforced phenolic composite for high‐performance structural applications
Authors: Kumar Ravindra , Kar Kamal K. , Dasgupta Kinshuk
Published: September 2020

In the present study, carbon nanotubes (CNTs) were grown up on nickel‐coated carbon textiles utilizing acetylene gas as a carbon precursor in an isothermal CVD reactor. The effects of CNT coating time (0 to 25 min) in the carbon textile‐phenolic composites (CPCs) prepared via conventional hand‐layup technique followed by compression molding were assessed using microstructures, static and dynamic mechanical thermal analysis, density and electrical properties. Significant improvement was observed in static as well as dynamic mechanical properties and electrical properties for all the CNT coated samples. Though, 15 min coating time gives the optimum results. The results showed ~71, 74, 62, 67, 38, and 45% increment in storage modulus, loss modulus, flexural strength, flexural modulus, tensile strength, Young's modulus, respectively. Furthermore, huge improvement (707%) in electrical conductivity and significant enrichment in thermal stability mark CNTs coated carbon textile as the efficient alternative reinforcement for high‐performance thermo‐structural applications such as aerospace and automotive fields.
Endemic amphibians cornered in headwaters by trout invasion in a mountain range in Argentina
Authors: Miloch Daniela , Bonino Andrea , Leynaud Gerardo C. , Lescano Julián N.
Published: September 2020

The Sierras Pampeanas Centrales, one of the most important extra‐Andean mountain systems of Argentina, harbour endemic and threatened amphibian species. In the past century, two alien predatory fish species (brook trout and rainbow trout) were introduced into rivers and streams of the area where amphibian species breed.

We hypothesized that the presence of trout would adversely affect the distribution of native amphibians in streams of the area. To test this hypothesis, the habitat requirements of trout and native amphibians were compared, and the effect of trout presence on amphibian occurrence was evaluated.

Transects (n = 126) were surveyed along rivers and streams in high‐altitude grasslands of the area, and the occurrences of trout and amphibians and habitat variables were recorded.

The habitat requirements of each species were compared using multivariate methods. Generalized linear mixed models were used to evaluate whether the occurrence of amphibians depends on trout, habitat variables or both. The distribution of each species between streams orders was assessed.

The results showed that the presence of trout was the main factor conditioning the distribution of two endemic amphibian species (Boana cordobae and Odontophrynus achalensis) in basins of the study area.

This threat needs to be incorporated urgently into action plans to guide conservation efforts towards the management of trout populations.
One size does not fit all: A study of badge behavior in stack overflow
Authors: Yanovsky Stav , Hoernle Nicholas , Lev Omer , Gal Kobi
Published: September 2020

Badges are endemic to online interaction sites, from question and answer (Q&A) websites to ride sharing, as systems for rewarding participants for their contributions. This article studies how badge design affects people's contributions and behavior over time. Past work has shown that badges “steer” people's behavior toward substantially increasing the amount of contributions before obtaining the badge, and immediately decreasing their contributions thereafter, returning to their baseline contribution levels. In contrast, we find that the steering effect depends on the type of user, as modeled by the rate and intensity of the user's contributions. We use these measures to distinguish between different groups of user activity, including users who are not affected by the badge system despite being significant contributors to the site. We provide a predictive model of how users change their activity group over the course of their lifetime in the system. We demonstrate our approach empirically in three different Q&A sites on Stack Exchange with hundreds of thousands of users, for two types of activities (editing and voting on posts).
Coprime factorization of polytopic LPV systems based on a homogeneous polynomial approach
Authors: Pereira Renan Lima , Heinz Kienitz Karl , de Oliveira Matheus Senna
Published: September 2020

This paper presents novel linear matrix inequalities (LMI)‐based conditions to address the coprime factorization problem for polytopic linear parameter‐varying (LPV) systems in both the continuous‐ and discrete‐time cases. The proposed conditions rely on the use of homogeneous polynomial parameter‐dependent (HPPD) matrix solutions of arbitrary degree g, which are used to obtain coprime factorization descriptions subject to time‐varying parameters defined inside a polytopic structure with known vertices. For a given degree g, synthesis of right and left coprime factorizations in terms of two special state‐feedback and filtering problems under quadratic
performance are provided. Existence conditions are given from linear matrix inequalities relaxations based on an extension of Pólya's theorem and the HPPD approach. The effectiveness of the proposed conditions is evaluated by means of numerical examples.
Distributed position estimation approach for multiagent formation with size scaling
Authors: Djamari Djati Wibowo
Published: September 2020

This work studies formation control of multiagent systems (MASs) where its formation size is scalable via a scaling factor (scalable formation). Past works on scalable formation are limited to either fixed undirected graph or fixed directed graph with p‐rooted graph condition. This work proposes a new distributed algorithm for scalable formation based on a distributed observer to estimate agents' positions. The new algorithm results in a new matrix, a Laplacian matrix with additional diagonal terms, where the desired formation pattern is embedded in this diagonal terms. With the proposed algorithm, only spanning tree condition is needed as the necessary and sufficient condition to achieve the scalable formation. Numerical examples are shown to illustrate the proposed method.
Proteomic exploration of soft and hard biocorona onto PEGylated multiwalled carbon nanotubes
Authors: Nicoletti Maria , Gambarotti Cristian , Fasoli Elisa
Published: September 2020

In nanomedicine, carbon nanotubes (CNTs) are considered potential candidates as drug delivery systems. The absorption of proteins onto CNTs, after their administration in physiological environment, forms the protein corona or biocorona, which is able to influence their biological properties and biocompatibility. For this reason, characterization of protein corona is a crucial aspect in the research to control CNTs toxicity and capability to target cells.

Multiwalled carbon nanotubes (MWCNTs) were functionalized with polyethylene glycol (PEG), chosen considering its well‐known biocompatibility, and then incubated in human plasma to create the biocorona. Plasma proteins, which bound around PEGylated CNTs, were detached using five different solutions, grouped into native and denaturant buffers, and used to characterize the two components of biocorona. The proteomic fingerprinting of biocorona was performed by SDS‐PAGE and 2D‐PAGE separation and mass spectrometry analysis. Native eluents were able to capture proteins of soft corona, characterized by complex secondary structures, and formed by both β‐sheet and α‐helices domains. Denaturant buffers have eluted many proteins with a high percentage of the α‐helix structure that could be involved in specific interactions responsible for the formation of hard corona.