bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancing the Performance of an HTPE Binder by Adding a Novel Hyperbranched Multi‐Arm Azide Copolyether
Authors: Wen Xiaomu , Zhang Guangpu , Chen Keke , Yuan Shen , Luo Yunjun 
Published: March 2020

AbstractModern composite solid propellants must exhibit excellent mechanical properties together with high energy outputs, and the binder system plays a vital role in establishing these characteristics. In the present work, varying proportions of a novel hyperbranched multi‐arm azide copolyether (POG) were combined with a hydroxyl‐terminated polyether (HTPE) to prepare crosslinked elastomeric binders. The compatibility of the POG and HTPE was demonstrated before a series of HTPE/POG blend binders were prepared based on a urethane reaction using hexamethylene diisocyanate (HMDI) as the curing agent. The mechanical properties of HTPE/POG/HMDI elastomers were found to be superior to those of traditional HTPE/N100 crosslinked binders as a result of the formation of a hyperbranched crosslink structure. Evaluations of the local motions of polymers chains and parameters related to the cured network structure demonstrated the advantages of introducing the hyperbranched POG. Hydrogen bonding in the HTPE/POG/HMDI binder was investigated and the results confirmed that these elastomers also benefited from hydrogen bonding, as well as the entanglement and interpenetration of molecular chains. Decomposition behavior was studied by thermogravimetric analysis, differential thermogravimetry and differential scanning calorimetry, and the new binders exhibited good thermal stability and superior energetic performance that could potentially meet the requirements for military applications.
Gradient Denitration Strategy Eliminates Phthalates Associated Potential Hazards During Gun Propellant Production and Application
Authors: Li Shiying , Tao Zhongan , Ding Yajun , Liang Hao , Zhao Xianzheng , Xiao Zhongliang , Li Chunzhi , Ou Jiangyang 
Published: March 2020

AbstractPhthalates, which often have to be used as deterrents during gun propellants production for realizing progressive burning, are widely believed to be harmful to human and the environment. Meanwhile, phthalates also generate much smoke during propellant combustion, thus, lowering firing accuracy and exposing positions, which may bring risk. To avoid phthalates usage during propellants production, this work, for the first time, reported the employment of “gradient denitration” strategy to prepare nitrocellulose‐based gun propellant without the addition of any phthalate deterrents. The successful preparation of gradiently denitrated gun propellant (GDGP) was supported by FT‐IR, Raman spectroscopy and FESEM equipped with energy‐dispersive X‐ray spectroscopy (EDS), as evidenced by the gradiently increased content of nitrogen and nitrate group from the surface to the core of GDGP. Such a denitration process, without any hazardous phthalates deterrents addition, could also realize the good progressive burning performance of the gun propellant, as confirmed by closed bomb test and ballistic gun test. Meanwhile, both theoretical calculation and weapon muzzle smoke test also demonstrated the lowering of smoke generation during propellant combustion. This phthalates‐free strategy paves a new way to eliminate potential hazards associated with phthalates during traditional gun propellant production and application.
Evaluating the GECCO3 1948–2018 ocean synthesis – a configuration for initializing the MPI‐ESM climate model
Authors: Köhl Armin 
Published: March 2020

AbstractThe paper describes an update of the GECCO (German contribution to the Estimating the Circulation and Climate of the Ocean project) ocean synthesis, now in its version 3, and provides an evaluation of the results with assimilated and independent data. GECCO3 covers the 71‐year period 1948–2018 and differs from its predecessor by returning to a single assimilation window instead of partitioning the period in 5‐year‐long overlapping windows which was previously necessary to yield convergence. A solution to the convergence problem is presented. GECCO3 is intended to be used for the initialization of coupled climate models and is configured for the higher‐resolution version of the earth system model (MPI‐ESM) developed at the Max Planck Institute for Meteorology. It uses the bathymetry and grid of the MPI‐ESM with quasi‐uniform resolution of 0.4°, thereby providing the first global eddy‐permitting synthesis based on the adjoint method. The synthesis additionally features the estimation of various mixing parameters and can regionally choose between explicit or parametrized eddy fluxes. Except for the altimeter data in tropical regions, GECCO3 is in better agreement with the assimilated data than GECCO2. The improvements relative to the in situ data partly result from the much larger amount of Argo data, which show lower model–data differences. Global heat content changes are in good agreement with recent estimates, but show uptake almost exclusively in the top 700 m. An alternative version of GECCO3, created by starting from different first‐guess control parameters, was used to evaluate the uncertainty of the estimated parameters and state due to lack of convergence. This estimate suggests a large uncertainty related to the uptake of heat into the lower layers, while estimates of mean meridional transport of heat and freshwater are not affected.
The potential use of operational radar network data to evaluate the representation of convective storms in NWP models
Authors: Stein Thorwald H. M. , Scovell Robert W. , Hanley Kirsty E. , Lean Humphrey W. , Marsden Nicola H. 
Published: March 2020

AbstractOperational forecasting centres increasingly rely on convection‐permitting NWP simulations to assist in their forecasting of convective events. The evaluation of upgrades in the underlying NWP modelling system normally happens through routine verification using traditional metrics on two‐dimensional fields, such as gridded rainfall data. Object‐ and process‐based evaluation can identify specific physical mechanisms for model improvement, but such evaluation procedures normally require targeted and expensive field campaigns. Here, we explore the potential use of the UK operational radar network observations and its derived 3D composite product for evaluating the representation of convective storms in the Met Office Unified Model. A comparison of the 1 × 1 × 0.5 km 3D radar composites against observations made with the research‐grade radar at Chilbolton in the southern UK indicates that the 3D radar composite data can reliably be used to evaluate the morphology of convective storms. The 3D radar composite data are subsequently used to evaluate the development of convective storms in the Met Office Unified Model. Such analysis was previously unavailable due to a lack of 3D radar data of high temporal frequency. The operational nature of the UK radar data makes these 3D composites a valuable resource for future studies of the initiation, growth, development, and organisation of convective storms over the
UK.
Remaining useful life prediction via a variational autoencoder and a time‐window‐based sequence neural network
Authors: Su Chun , Li Le , Wen Zejun 
Published: March 2020

AbstractThe prediction of remaining useful life (RUL) has attracted much attention, and it is also a key section for predictive maintenance. In this study, a novel hybrid deep learning framework is proposed for RUL prediction, where a variational autoencoder (VAE) and time‐window‐based sequence neural network (twSNN) are integrated. Among it, VAE is used to extract the hidden and low‐dimensional features from the raw sensor data, and a loss function is designed to extract useful data features; by using a sliding time window, twSNN can predict RUL dynamically; meanwhile, it can simplify the network architecture in the time dimension. Furthermore, to achieve higher performance on various failure conditions, long short‐term memory (LSTM) cell and convolutional LSTM (ConvLSTM) cell are designed for twSNN respectively. A case study is completed with a dataset of aircraft turbine engines. It is found that the proposed frameworks with LSTM cell and ConvLSTM cell have better performance on both single failure mode and multiple failure modes. The results also show that the prediction accuracy is averagely improved by 6.65% for single failure mode and 15.05% for multiple failure modes respectively.
Structures, g‐tensors, and hyperfine coupling constants of L‐α‐alanine radicals in radiation dosimetry: An ab initio molecular dynamics simulation study
Authors: Janbazi Mehdi , Azar Yavar T. , Ziaie Farhood , Ghandi Khashayar , Matta Chérif F. , Shadman Lakmehsari Muhammad 
Published: March 2020

AbstractAlanine is used as a transfer standard dosimeter for gamma ray and electron beam calibration. An important factor affecting its dosimetric response is humidity which can lead to errors in absorbed dose calculations. Ab initio molecular dynamics calculations were performed to determine the environmental effects on the electron paramagnetic resonance (EPR) parameters of L‐α‐alanine radicals in acidic and alkaline solutions. A new result, not dissimilar to the closed‐shell amino acid molecule alanine, is that the non‐zwitterionic form of the alanine radical is the stable form in the gas phase while the zwitterionic neutral alanine radical is not a stable structure in the gas phase. Geometric and EPR parameters of radicals in both gas and solution phases are found to be dependent on hydrogen bonding of water molecules with the polar groups and on dynamic solvation. Calculations on the optimized free radicals in the gas phase revealed that for the neutral radical, hydrogen bonding to water molecules drives a decrease in the magnitudes of g‐tensor components g
xx and g
yy without affecting neither g
zz component nor the hyperfine coupling constants (HFCCs). The transfer from the gas to solution phase of the alanine radical anion is accompanied with an increase in the spin density on the carboxylic group's oxygen atoms. However, for the neutral radical, this transfer from gas to solution phase is accompanied with the decrease in the spin density on oxygen atoms. Calculated isotropic HFCCs and g‐tensor of all radicals are in good agreement with experiment in both acidic and alkaline solutions.
In search of the smallest boroxol‐type heterocyclic ring system: Planar hexagonal B3S3+ cluster with double 6π/2σ aromaticity
Authors: Zhang Li‐Juan , Feng Lin‐Yan , Bian He , Pei Ling , Li Da‐Zhi , Zhai Hua‐Jin 
Published: March 2020

AbstractBoroxol (B3O3) rings and relevant hexagonal B3S3 structural blocks are ubiquitous in boron oxide/sulfide glasses, crystals, and high‐temperature liquids. However, the isolation of an ultimate heterocyclic B3O3 or B3S3 cluster in the free‐standing form, with as few as six atoms, has been unsuccessful so far. We report on computational design of the simplest case of such a system: the highly symmetric D3h B3S3+ (1A1′) cluster. It is the well‐defined global minimum on the potential energy surface, following global searches and electronic structure calculations at the B3LYP and single‐point CCSD(T) levels. Chemical bonding analysis reveals an ideal system with skeleton Lewis BS σ single bonds and unique double 6π/2σ aromaticity, which underlies its stability. The cluster turns out to be an inorganic analog of the 3,5‐dehydrophenyl cation, a typical double π/σ aromatic system. It offers an example for chemical analogy between boron‐based heterocyclic clusters and aromatic hydrocarbons. Double π/σ aromaticity is also a new concept in heterocyclic boron clusters. Previous systems such as borazine, boroxine, and boronyl boroxine only deal with π aromaticity as in benzene.
Nanostructuring Co3O4 to Tune Capacitive Behaviors: From Low to High Dimensions
Authors: Yang Pingping , Wu Fengkai , Wang Liuliu , Chen Xiaoying , Xie Jiale 
Published: March 2020

AbstractPseudocapacitance is mainly contributed by fast surface‐controlled reactions. However, the effect of nanostructures on the capacitive behaviour has not been systematically studied yet. In this work, we synthesize different Co3O4 nanostructures with the same crystal structure and exposed clean crystal planes that include 1D nanowire, 2D nanosheet, 3D rambutan‐like and hierarchical structures, ranging from low to high dimensions. It is discovered the specific capacitance of Co3O4 materials follows the order of 1D nanowire > hierarchical structure > 2D nanosheet > 3D rambutan‐like structure while the electron transfer resistance is 1D nanowire < 2D nanosheet < hierarchical structure < 3D rambutan‐like structure. Under the same electrochemistry, results suggest the pseudocapacitance is not simply dependent on the surface area offered by the nanostructure, but relies on the conductivity, accessibility, diffusion rate and reactivity of the electrode. 1D nanostructure can render the highest reactant accessibility, fastest electron transfer and largest diffusion rate, thus achieving the highest specific pseudocapacitance.
Egg Yolk Biomass Derived N‐Doped Ordered Mesoporous Carbon: Highly Robust Heterogeneous Organocatalyst for One‐Pot Deacatalization‐Knoevenagel Reaction
Authors: Nadem Sahar , Vahdati‐Khajeh Saleh , Eftekhari‐Sis Bagher 
Published: March 2020

AbstractA novel and facile synthetic route for CMK‐3 type N‐rich ordered mesoporous carbon from cheap egg yolk biomass as a carbon precursor (EYCP) and SBA‐15 as a hard structure directing agent has been developed. To obtain a well‐ordered material, carbonization temperature was investigated. The N2 adsorption‐desorption analysis proved that the synthetic mesoporous carbon material at 500 °C is highly ordered, with high surface area of 226 m2 g−1, and nitrogen content of 6.2% was determined by CHN analysis. Corresponding mesoporous materials were examined as bifunctional acid‐base organocatalysts in a one‐pot tandem deacetalization‐Knoevenagel reaction. Results showed that the modified carbon material which was synthesized at 500 °C exhabited high nitrogen content and reactivity in one‐pot deacetalization‐Knoevenagel reaction. Carboxylic acid and pyridinic nitrogen groups of carbon material play as a bifunctional acid and base catalyst.
Catalytic Performance of In/HZSM‐5 for Coupling Propane with CO2 to Propylene
Authors: Tian Haifeng , Liao Jiankang , Zha Fei , Guo Xiaojun , Tang Xiaohua , Chang Yue , Ma Xiaoxun 
Published: March 2020

AbstractThe dehydrogenation of propane to propylene is endothermic reaction will generate hydrogen, while the hydrogenation of CO2 to light olefins is exothermic reaction with hydrogen as reactant. Using the CO2 hydrogenation reaction to consume the hydrogen from the propane dehydrogenation reaction, which is more beneficial to propylene generation. Thus, a promising approach of coupling propane with CO2 to produce propylene was proposed. A simple wetness impregnation method was used to prepare the In/HZSM‐5 composite catalyst for this coupling reaction. It was characterized by means of XRD, SEM, TEM, H2‐TPR, NH3‐TPD, XPS, TG, and N2 isothermal adsorption‐desorption. Effects of indium loading, feed volume ratio of propane to CO2, reaction pressure and temperature on the coupling of propane with CO2 to propylene were investigated in a fixed‐bed reactor. When the mass content of indium is 12%, the feeding volume ratio of propane to CO2 is 1 : 4, the reaction pressure is 0.3 MPa and the reaction temperature is 580 °C, the propylene selectivity is 71.41%, as well as the conversion per pass of propane and CO2 is 17.74% and 5.08%, respectively.
Scalable Exfoliation and High‐Efficiency Separation Membrane of Boron Nitride Nanosheets
Authors: Wang Zhen , Zhu Yanjiao , Ji Dong , Li Zhifeng , Yu Haibin 
Published: March 2020

AbstractHexagonal boron nitride nanosheets (h‐BNNSs) refer to a class of two‐dimensional materials with promising applications. However, the current method of exfoliating hexagonal boron nitride (h‐BN) into h‐BNNS limits its large‐scale application. Herein, a method was developed to exfoliate h‐BN through sucrose assisted discontinuous, multiple ball milling. A series of defect‐free, ultra‐thin large lateral‐size h‐BNNSs were successfully obtained, with a yield as high as 85 wt %. Finally, the membranes of BNNS obtained by vacuum filtration displayed a good separation performance in different organic pigment solutions. The separation rates of BNNS‐20 membranes for methylene blue and Congo red reached 87 % and 95 %, respectively. The results show that the functionalized h‐BNNSs obtained by sucrose‐assisted discontinuation, multiple ball milling have good stability in water, and hence can be applied to wastewater treatment.
Engineering Biomimetic Nanofiber Microspheres with Tailored Size, Predesigned Structure, and Desired Composition via Gas Bubble–Mediated Coaxial Electrospray
Authors: John Johnson V. , McCarthy Alec , Wang Hongjun , Chen Shixuan , Su Yajuan , Davis Ethan , Li Xiaowei , Park Jae Sung , Reinhardt Richard A. , Xie Jingwei 
Published: March 2020

AbstractMinimally invasive therapies avoiding surgical complexities evoke great interest in developing injectable biomedical devices. Herein, a versatile approach is reported for engineering injectable and biomimetic nanofiber microspheres (NMs) with tunable sizes, predesigned structures, and desired compositions via gas bubble–mediated coaxial electrospraying. The sizes and structures of NMs are controlled by adjusting processing parameters including air flow rate, applied voltage, distance, and spinneret configuration in the coaxial setup. Importantly, unlike the self‐assembly method, this technique can be used to fabricate NMs from any material feasible for electrospinning or other nanofiber fabrication techniques. To demonstrate the versatility, open porous NMs are successfully fabricated that consist of various short nanofibers made of poly(ε‐caprolactone), poly(lactic‐co‐glycolic acid), gelatin, methacrylated gelatin, bioglass, and magneto‐responsive polymer composites. Open porous NMs support human neural progenitor cell growth in 3D with a larger number and more neurites than nonporous NMs. Additionally, highly open porous NMs show faster cell infiltration and host tissue integration than nonporous NMs after subcutaneous injection to rats. Such a novel class of NMs holds great potential for many biomedical applications such as tissue filling, cell and drug delivery, and minimally invasive tissue regeneration.
A sorghum practical haplotype graph facilitates genome‐wide imputation and cost‐effective genomic prediction
Authors: Jensen Sarah E. , Charles Jean Rigaud , Muleta Kebede , Bradbury Peter J. , Casstevens Terry , Deshpande Santosh P. , Gore Michael A. , Gupta Rajeev , Ilut Daniel C. , Johnson Lynn , Lozano Roberto , Miller Zachary , Ramu Punna , Rathore Abhishek , Romay M. Cinta , Upadhyaya Hari D. , Varshney Rajeev K. , Morris Geoffrey P. , Pressoir Gael , Buckler Edward S. , Ramstein Guillaume P. 
Published: March 2020

AbstractSuccessful management and utilization of increasingly large genomic datasets is essential for breeding programs to accelerate cultivar development. To help with this, we developed a Sorghum bicolor Practical Haplotype Graph (PHG) pangenome database that stores haplotypes and variant information. We developed two PHGs in sorghum that were used to identify genome‐wide variants for 24 founders of the Chibas sorghum breeding program from 0.01x sequence coverage. The PHG called single nucleotide polymorphisms (SNPs) with 5.9% error at 0.01x coverage—only 3% higher than PHG error when calling SNPs from 8x coverage sequence. Additionally, 207 progenies from the Chibas genomic selection (GS) training population were sequenced and processed through the PHG. Missing genotypes were imputed from PHG parental haplotypes and used for genomic prediction. Mean prediction accuracies with PHG SNP calls range from .57–.73 and are similar to prediction accuracies obtained with genotyping‐by‐sequencing or targeted amplicon sequencing (rhAmpSeq) markers. This study demonstrates the use of a sorghum PHG to impute SNPs from low‐coverage sequence data and shows that the PHG can unify genotype calls across multiple sequencing platforms. By reducing input sequence requirements, the PHG can decrease the cost of genotyping, make GS more feasible, and facilitate larger breeding populations. Our results demonstrate that the PHG is a useful research and breeding tool that maintains variant information from a diverse group of taxa, stores sequence data in a condensed but readily accessible format, unifies genotypes across genotyping platforms, and provides a cost‐effective option for genomic selection.
Golf Courses as Potential Habitat for Urban Coyotes
Authors: Wurth Ashley M. , Ellington E. Hance , Gehrt Stanley D. 
Published: March 2020

ABSTRACTWildlife increasingly live in and adapt to urban landscapes as natural habitat becomes urbanized. Many carnivores take advantage of undeveloped or open developed areas called green spaces, such as parks or cemeteries, to meet their requirements in urban areas. For instance, coyotes (Canis latrans) expanded their range across most of North America into metropolitan areas and even within highly developed areas, where home ranges of coyotes are associated with green spaces or areas that humans used least. Golf courses are a unique type of green space within urban landscapes that can provide cover and prey for coyotes, as well as limit human presence, especially at night and during the winter off‐season. We estimated selection of golf courses and urban green spaces by coyotes within the Chicago Metropolitan Area, Illinois, USA (2009 to 2012) that had access to golf courses (home range composed of >3% golf course; n = 30) using radiotelemetry. We found that coyotes selected for golf courses more at night and during the off‐season, indicating that they were responding to the decreased human presence during this time. Spatial status (resident vs. transient) and the amount of developed land in a home range did not influence selection of golf courses. Conversely, selection of urban green spaces was greater in the summer for transients and with proportion of developed land, but not influenced by time of day. However, there was considerable intra‐ and inter‐individual variability in coyote selection of both golf courses and urban green spaces. Individual variability could be driven by coyote characteristics (i.e., prey preferences, natal habitat, or social status) or by golf course and urban green space characteristics (i.e., landscaping, golfing hours, average human occupancy, or tolerance by personnel). © 2020 The Wildlife Society.
Multiscale modeling of vertebrate limb development
Authors: Glimm Tilmann , Bhat Ramray , Newman Stuart A. 
Published: March 2020

AbstractWe review the current state of mathematical modeling of cartilage pattern formation in vertebrate limbs. We place emphasis on several reaction–diffusion type models that have been proposed in the last few years. These models are grounded in more detailed knowledge of the relevant regulatory processes than previous ones but generally refer to different molecular aspects of these processes. Considering these models in light of comparative phylogenomics permits framing of hypotheses on the evolutionary order of appearance of the respective mechanisms and their roles in the fin‐to‐limb transition.This article is categorized under:
Analytical and Computational Methods > Computational Methods
Models of Systems Properties and Processes > Mechanistic Models
Developmental Biology > Developmental Processes in Health and Disease
Analytical and Computational Methods > Analytical Methods