bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of chemical reactions in the stagnation point heat flux of rarefied hypersonic cylinder flows
Authors: Chen Hao , Zhang Bin , Liu Hong
Published: September 2020

This work investigates the variations of the stagnation point heat flux (SPHF) in hypersonic cylinder flows using the direct simulation Monte Carlo method, with the consideration of a constant freestream Knudsen number but different cylinder diameters. Four different freestream Mach numbers and the accompanying chemical reactions are considered. The result reveals a high-density effect in chemical reactions inside the thermal boundary layer, which induces an increasingly rising SPHF with a decreased cylinder diameter for all the cases. The cases at Ma∞ = 30 exhibit a characteristic of peculiarity that the value of SPHF increases the fastest, which is strongly correlated with the different high-density effects at different Ma∞. Further analysis demonstrates that the NO dissociation and recombination reactions always play a vitally important role in the high-density effect. A secondary NO dissociation reaction was observed inside the thermal boundary layer when Ma∞ > 30. This observation is the result of the shift of chemical equilibrium induced by violent recombination reaction and sufficiently high flow temperature. Subsequently, the newly emerging secondary dissociation reaction weakens the influence of recombination reaction; thus, the growth of SPHF at a high Mach number is not so strong as that with Ma∞ ≤ 30. Furthermore, in order to provide more reliable results, additional simulations are discussed by employing the widely accepted total collision energy and catalytic surface reaction models.
Granular flow in rotating drums through simulations adopting a continuum constitutive equation
Authors: Arseni Angelica M. G. , De Monaco Gaetano , Greco Francesco , Maffettone Pier Luca
Published: September 2020

The need for a detailed description of dense granular flows arises in several practical applications. A continuum approach, where the solid phase is treated as a continuum, is suitable for large-scale flow modeling, as in the case of an industrial drum containing billions of particles. In this work, we present three-dimensional finite volume simulations of dense granular flow inside a rotating cylinder, adopting the viscoplastic Jop–Forterre–Pouliquen constitutive model for the granular medium stress tensor [Jop et al., “A constitutive law for dense granular flows,” Nature 441, 727–730 (2006)], the so-called μ(I)-rheology. The results obtained from our simulations are also compared with several experimental results available in the literature. Qualitative and even quantitative agreement with data is found: we are able to reproduce the experimentally observed flow regime sequence in rotating drums, ranging from rolling to centrifuging, and to predict flow fields of interest within the granular phase in agreement with experimental results, not only on the drum center but also along the axial direction. This approach characterizes a wide variety of regimes by changing both physical and geometrical parameters and gives details on several flow quantities difficult to be accessed through experiments, but of practical interest.
Fast, accurate enthalpy differences in spin crossover crystals from DFT+U
Authors: Ohlrich Miriam , Powell Ben J.
Published: September 2020

Spin crossover materials are bi-stable systems with potential applications as molecular scale electronic switches, actuators, thermometers, barometers, and displays. However, calculating the enthalpy difference, ΔH, between the high spin and low spin states has been plagued with difficulties. For example, many common density functional theory (DFT) methods fail to even predict the correct sign of ΔH, which determines the low temperature state. Here, we study a collection of Fe(II) and Fe(III) materials, where ΔH has been measured, which has previously been used to benchmark density functionals. The best performing hybrid functional, TPSSh, achieves a mean absolute error compared to experiment of 11 kJ mol−1 for this set of materials. However, hybrid functionals scale badly in the solid state; therefore, local functionals are preferable for studying crystalline materials, where the most interesting spin crossover phenomena occur. We show that both the Liechtenstein and Dudarev DFT+U methods are a little more accurate than TPSSh. The Dudarev method yields a mean absolute error of 8 kJ mol−1 for Ueff = 1.6 eV. However, the mean absolute error for both TPSSh and DFT+U is dominated by a single material, for which the two theoretical methods predict similar enthalpy differences—if this is excluded from the set, then DFT+U achieves chemical accuracy. Thus, DFT+U is an attractive option for calculating the properties of spin crossover crystals, as its accuracy is comparable to that of meta-hybrid functionals, but at a much lower computational cost.
Temperature-dependent phonon mode and interband electronic transition evolutions of ε-InSe films derived by pulsed laser deposition
Authors: Xie Mingzhang , Li Ming , Li Liumeng , Zhang Jinzhong , Jiang Kai , Shang Liyan , Li Yawei , Hu Zhigao , Chu Junhao
Published: September 2020

We report the temperature-dependent phonon modes and interband electronic transitions of InSe films on SiO2/Si substrates prepared by pulsed laser deposition. The microstructure results proved the ε phase structure and monochalcogenide phase composition with well-defined hexagonal InSe sheets. The temperature effects on lattice vibrations were discovered by Raman spectra from 123 K to 423 K. The frequency and full width at half maximum of the A2g1(LO) mode show a strong nonlinearity with the temperature. The energy band structure and electron–phonon interaction were studied by temperature-dependent spectroscopic ellipsometry with the aid of the Tauc–Lorentz model. It was found that five electronic transitions around 1.33, 1.61, 2.53, 3.73, and 4.64 eV generally show a redshift trend with the temperature. The present results can provide a valuable reference for future optoelectronic applications of InSe films.
Anchoring mechanisms of a holder-stabilized premixed flame in a preheated mesoscale combustor
Authors: Wan Jianlong , Zhao Haibo , Akkerman V’yacheslav
Published: September 2020

A very lean-premixed, laminar methane–air flame is demonstrated, experimentally, to be stable in a mesoscale combustor with a flame holder. Unlike the anchoring location of the flame tip, the anchoring location of the flame root is practically independent of the equivalence ratio, inlet velocity, and thermal conductivity of the solid wall material. When the mixture becomes leaner, both the flame root and tip can adaptively shift toward the locations with higher temperatures, and additionally, the anchoring temperature of the flame root is higher. Subsequently, by means of the three-dimensional computational mechanics, their anchoring mechanisms are thoroughly analyzed in terms of the flow recirculation, stretch effect, preferential diffusion, and conjugate heat exchange. A recirculation zone or a low-velocity zone formed behind/near the flame holder and combustion chamber wall can assist the balance between the flow velocity and the flame speed for the flame anchoring, and the flame root can adaptively shift to a zone of lower local velocity. The stretch effect is not responsible for the flame root anchoring, but this effect stabilizes the flame tip by increasing the local flame speed near the flame tip. Preferential diffusion significantly promotes the local equivalence ratio near the anchoring location of the flame root, thereby facilitating the stability of this flame root, though it stabilizes the flame tip only slightly. Furthermore, the conjugate heat exchange plays an important role in preheating fuel/air and intensifying combustion, which influences the stabilization of both the flame root and tip. The shorter distance between the flame tip and the combustion chamber wall results in a stronger flame–wall coupling. These results indicate that the anchoring mechanisms for the flame root and tip differ.
Hidden dynamic signatures drive substrate selectivity in the disordered phosphoproteome
Authors: Cho Min-Hyung , Wrabl James O. , Taylor James , Hilser Vincent J.
Published: September 2020

Significance

The discovery that more than 40% of the eukaryotic proteome is intrinsically disordered, and that these disordered segments are enriched in phosphorylation sites, suggests that conformational heterogeneity may be important to kinase selectivity. Indeed, phosphorylation prediction programs reliant on classic notions of conserved sequence information (i.e., “vertical information”) are only partially effective. We find that the conformational equilibrium of the phosphorylatable site, whose information is embedded in sequence-averaged energetic and structural properties of the protein (i.e., “horizontal information”), plays a major role in distinguishing phosphorylatable versus nonphosphorylatable sites. In fact, employing both horizontal and vertical information produces a state-of-the-art phosphorylation predictor, wherein the conformational equilibrium of the disordered chain is the dominant contributor.
CSF1R inhibition by a small-molecule inhibitor is not microglia specific; affecting hematopoiesis and the function of macrophages
Authors: Lei Fengyang , Cui Naiwen , Zhou Chengxin , Chodosh James , Vavvas Demetrios G. , Paschalis Eleftherios I.
Published: September 2020

Colony-stimulating factor 1 receptor (CSF1R) inhibition has been proposed as a method for microglia depletion, with the assumption that it does not affect peripheral immune cells. Here, we show that CSF1R inhibition by PLX5622 indeed affects the myeloid and lymphoid compartments, causes long-term changes in bone marrow-derived macrophages by suppressing interleukin 1β, CD68, and phagocytosis but not CD208, following exposure to endotoxin, and also reduces the population of resident and interstitial macrophages of peritoneum, lung, and liver but not spleen. Thus, small-molecule CSF1R inhibition is not restricted to microglia, causing strong effects on circulating and tissue macrophages that perdure long after cessation of the treatment. Given that peripheral monocytes repopulate the central nervous system after CSF1R inhibition, these changes have practical implications for relevant experimental data.
Ultra-sharp pinnacles sculpted by natural convective dissolution
Authors: Huang Jinzi Mac , Tong Joshua , Shelley Michael , Ristroph Leif
Published: September 2020

Significance

This work reveals a mechanism that may contribute to the formation of sharply pointed rock spires in karst or dissolved landforms such as stone forests. We show that solids dissolving into liquids in the presence of gravity naturally produce flows that carve ultra-sharp spikes. Better understanding the origin of these delicate structures may aid in natural conservation efforts. Our experimental and theoretical techniques may also be applied to other problems in geomorphology and phase-change processes such as ice melting. The mechanism could be used to manufacture fine-scale structures, and our theory provides the relevant control parameters.
TRIM28 functions as the SUMO E3 ligase for PCNA in prevention of transcription induced DNA breaks
Authors: Li Min , Xu Xiaohua , Chang Chou-Wei , Liu Yilun
Published: September 2020

Significance

PCNA is an essential protein in DNA replication and repair, and these functions rely on multiple posttranslational modifications, including small ubiquitin-like modifiers SUMO1 and SUMO2. SUMO2-conjugated PCNA has a distinct function in maintaining genomic stability from SUMO1-conjugated PCNA. Therefore, different SUMO E3 ligases are needed to provide the specificity to covalently attach either SUMO1 or SUMO2 to PCNA in response to different replication stress. However, even though SUMO-conjugated PCNA molecules have been observed in human cells since 2012, to date, the SUMO E3 ligases for PCNA have yet to be identified. This paper reports a SUMO E3 ligase that directly conjugates SUMO2 to PCNA with high specificity to prevent transcription induced DNA breaks in human cells.
p53 drives a transcriptional program that elicits a non-cell-autonomous response and alters cell state in vivo
Authors: Moyer Sydney M. , Wasylishen Amanda R. , Qi Yuan , Fowlkes Natalie , Su Xiaoping , Lozano Guillermina
Published: September 2020

Significance

Although p53 is highly studied, the molecular and physiological consequences of the p53 transcriptional response are poorly understood. Through RNA sequencing of multiple mouse tissues upon genetic activation of p53, we identified hundreds of tissue-specific p53 target genes and a set of genes that is commonly expressed and can serve as a signature for p53 pathway activation. In the pancreas, we observed a non-cell-autonomous response while the small intestine displayed altered transcriptional cell states. Our study begins to uncover the commonalities and differences engrained in the tissue-specific and cell-specific p53 transcriptomes. Gaining a better understanding of the wild-type p53 transcriptome will subsequently lead to determining the elusive combination of genes responsible for the tumor-suppressive function of p53.
Ultranarrow plasmon resonances from annealed nanoparticle lattices
Authors: Deng Shikai , Li Ran , Park Jeong-Eun , Guan Jun , Choo Priscilla , Hu Jingtian , Smeets Paul J. M. , Odom Teri W.
Published: September 2020

Significance

The ability to control light has driven advances from optical microscopy to fast communication. Metal nanoparticles can trap light at the nanoscale in the form of surface plasmons; these localized excitations are important in sensing and designing miniaturized photonic devices. Although very narrow plasmon linewidths are desirable, they tend to be broad because of limitations in fabrication methods. Here, we describe how to achieve ultranarrow plasmon resonances with linewidths that approach the calculated limit by thermally annealing 2D lattices of metal nanoparticles. Our results indicate that exquisite control over structural features of nanoparticles can dramatically improve their plasmonic response and open promising strategies for manipulating light–matter interactions at the nanoscale.
Medin aggregation causes cerebrovascular dysfunction in aging wild-type mice
Authors: Degenhardt Karoline , Wagner Jessica , Skodras Angelos , Candlish Michael , Koppelmann Anna Julia , Wild Katleen , Maxwell Rusheka , Rotermund Carola , von Zweydorf Felix , Gloeckner Christian Johannes , Davies Hannah A. , Madine Jillian , Del Turco Domenico , Feederle Regina , Lashley Tammaryn , Deller Thomas , Kahle Philipp , Hefendehl Jasmin K. , Jucker Mathias , Neher Jonas J.
Published: September 2020

Significance

Vascular dysfunction, as it develops either during normal aging or vascular disease, remains a major medical problem. The amyloid Medin, which is derived from its precursor protein MFG-E8 (through unknown mechanisms), forms insoluble aggregates in the vasculature of virtually anybody over 50 years of age, and it has been hypothesized that Medin aggregation could contribute to age-associated vascular decline; however, mechanistic analyses have so far been lacking. Our data now demonstrate that reminiscent of humans, mice also develop Medin deposits in an age-dependent manner. Importantly, mice that genetically lack Medin show reduced vascular dysfunction in the aged brain. Therefore, the prevention of Medin accumulation should be investigated as a novel therapeutic approach to preserve vascular health in the aging population.
Direct characterization of solute transport in unsaturated porous media using fast X-ray synchrotron microtomography
Authors: Hasan Sharul , Niasar Vahid , Karadimitriou Nikolaos K. , Godinho Jose R. A. , Vo Nghia T. , An Senyou , Rabbani Arash , Steeb Holger
Published: September 2020

Significance

Solute transport in porous materials is pertinent to many engineering and industrial applications. This research provides direct characterization of spatiotemporal behavior of solute transport in saturated and unsaturated porous media using high-resolution four-dimensional synchrotron X-ray imaging. This research has two key impacts: 1) we demonstrate a workflow for direct characterization of solute transport in any porous material, which allows better design of fabricated porous materials and detailed characterization of natural porous materials, and 2) we evaluate the underlying assumptions used in the existing theories and identify the major gaps in theories that need to be addressed for better predictive modeling.
Liquid harvesting and transport on multiscaled curvatures
Authors: Li Chuxin , Yu Cunlong , Zhou Shan , Dong Zhichao , Jiang Lei
Published: September 2020

Significance

Although various creatures possess different structural gradients to gather water from fog, such as spider silk and cactus cluster, their gradient surfaces can only drive the motion of harvested water droplets over only a limited drop-sized distance and afford a slow speed, limiting the practical usage. The peristome of the pitcher plant presented here is a superior fog harvestor that capitalizes on the combined effects of ratchet, concavity, and arch structures to collect water from humid air and transport condensate water directionally along the curved peristome at a recording speed. Biomimetic approaches apply this multiscaled curvatures design to the construction of water fog and organic vapor harvestor, making it a versatile solution for a broad range of applications.
HDAC3 deacetylates the DNA mismatch repair factor MutSβ to stimulate triplet repeat expansions
Authors: Williams Gregory M. , Paschalis Vasileios , Ortega Janice , Muskett Frederick W. , Hodgkinson James T. , Li Guo-Min , Schwabe John W. R. , Lahue Robert S.
Published: September 2020

Significance

Triplet repeat expansions cause nearly 20 inherited neurological diseases. The molecular mechanism of expansions is of interest at two levels. First is the basic science of how triplet repeats expand, and the second is the therapeutic opportunity to treat expansion diseases. This study presents evidence that addresses both areas of interest. We show that the histone deacetylase HDAC3 acts directly on the DNA mismatch repair protein MutSβ to stimulate CAG•CTG repeat expansions. This basic science insight into the mechanism also provides an explanation for how HDAC3 inhibition in Huntington’s disease mice leads to suppression of triplet repeat expansions and could therefore be considered as a therapy for Huntington’s disease and potentially other CAG•CTG repeat expansion diseases.
Effects of water level alteration on carbon cycling in peatlands
Authors: Zhong Yehui , Jiang Ming , Middleton Beth A.
Published: September 2020

Globally, peatlands play an important role in the carbon (C) cycle. High water level is a key factor in maintaining C storage in peatlands, but water levels are vulnerable to climate change and anthropogenic disturbance. This review examines literature related to the effects of water level alteration on C cycling in peatlands to summarize new ideas and uncertainties emerging in this field. Peatland ecosystems maintain their function by altering plant community structure to adapt to changing water levels. Regarding primary production, woody plants are more productive in unflooded, well-aerated conditions, while
Sphagnum
mosses are more productive in wetter conditions. The responses of sedges to water level alteration are species-specific. While peat decomposition is faster in unflooded, well aerated conditions, increased plant production may counteract the C loss induced by increased ecosystem respiration (ER) for a period of time. In contrast, rising water table maintains anaerobic conditions and enhances the role of the peatland as a C sink. Nevertheless, changes in DOC flux during water level fluctuation is complicated and depends on the interactions of flooding with environment. Notably, vegetation also plays a role in C flux but particular species vary in their ability to sequester and transport C. Bog ecosystems have a greater resilience to water level alteration than fens, due to differences in biogeochemical responses to hydrology. The full understanding of the role of peatlands in global C cycling deserves much more study due to uncertainties of vegetation feedbacks, peat–water interactions, microbial mediation of vegetation, wildfire, and functional responses after hydrologic restoration.
Mapping the asymptotic inspiral of precessing binary black holes to their merger remnants
Authors: Reali Luca , Mould Matthew , Gerosa Davide , Varma Vijay
Published: September 2020

Multiple approaches are required to study the evolution of black-hole binaries. While the post-Newtonian (PN) approximation is sufficient to describe the early inspiral (even from infinitely large orbital separation), only numerical relativity can capture the full complexity of the dynamics near merger. We combine multi-timescale PN integrations with numerical-relativity surrogate models, thus mapping the entire history of the binary from its asymptotic configuration at past-time infinity to the post-merger remnant. This approach naturally allows us to assess the impact of the precessional and orbital phase on the properties—mass, spin, and kick—of the merger remnant. These phases introduce a fundamental uncertainty when connecting the two extrema of the binary evolution.
Size-dependent magnetic hardening in CoFe2O4 nanoparticles: effects of surface spin canting
Authors: Mohapatra Jeotikanta , Xing Meiying , Elkins Jacob , Beatty Julian , Liu J Ping
Published: September 2020

Magnetic cobalt ferrite CoFe2O4 is rich with physical phenomena, owing to its crystalline and magnetic structures. When such a ferrite is produced in a modulated nanoscale size, the increased specific surface area gives rise to even more complex behavior in its magnetism, particularly in relation to magnetic hardening. By correlating nanoparticle size (from 3.5 nm to 80 nm) with crystallite size and magnetic properties, we can observe interesting relations between particle size and magnetic coercivity. On exceeding the superparamagnetic limit of about 10 nm, room-temperature coercivity and remanence values are found to increase with increasing nanoparticle size, up to a maximum value of 4.1 kOe and 52 emu g−1, respectively, at a size of approximately 45 nm. Above this critical size, the nanoparticles are comprised of multiple crystallites, and demonstrate the existence of a cooperative phenomenon, the so-called interaction domains, which leads to a decrease in coercivity and remanence values. More interestingly, the ultrasmall-sized CoFe2O4 nanoparticles (3.5–16 nm) show an anomalous coercivity enhancement and irreversible behavior at low temperatures, as compared to the large-sized nanoparticles, which may be ascribed to enhanced effective magnetic anisotropy due to the surface spin-canting effect. Furthermore, training behavior in the exchange bias field, together with field-dependent blocking behavior, indicate that ultrasmall CoFe2O4 nanoparticles possess highly frustrated surface spins, which rearrange much more slowly than their interior spins, resulting in magnetic hardening at low temperatures.
Particle size and substrate wettability dependent patterns in dried pendant drops
Authors: Kumar P Logesh , Thampi Sumesh P , Basavaraj Madivala G
Published: September 2020

The particle laden sessile drops when dried on solid surfaces under certain conditions leave a deposit pattern wherein all the particles are confined to a narrow region close to the edge of the deposit. Such patterns which often form when coffee drops dry are referred to as the coffee ring patterns or the coffee stains. Recent research points to the formation of intriguing patterns when colloidal particle laden drops are dried in configurations other than sessile mode. In this article, the combined effect of particle size and wettability of the substrate on the patterns formed by drying drops in sessile and pendant configurations is investigated via experiments. Our results demonstrate a transition from coffee ring to central dome-like deposit morphology with decrease in wettability of the substrates when drops containing 3 μm diameter particles are dried in pendent mode. A similar transition in the deposit morphology is observed with increase in the diameter of the particles in pendant drops dried on substrates of near neutral wettability (θ = 86 ± 3°). The influence of particles size, substrate wettability and drop configuration on the kinetics of deposition of particles at the three phase contact line will also be discussed. We compare our experimental observations with particle based simulations wherein the dried patterns are generated by accounting for three particle transport modes, namely, advective particle transport resulting from capillary flow, gravity driven settling of particles and particle capture by descending interface.
Development of MnO2 hollow nanoparticles for potential drug delivery applications
Authors: Greene Allison , Hashemi Jonathon , Kang Yunqing
Published: September 2020

This study reports the development of hollow nanoparticles, formed from manganese dioxide (δ-MnO2) sheets, that are coated with polydopamine for potential immobilization of chemical agents. The biodegradability and colloidal stability of the uncoated hollow MnO2 nanoparticles were investigated in comparison to commercially synthesized solid MnO2 nanoparticles and graphene oxide sheets. The MnO2 hollow nanoparticles degraded at a faster rate and seem to have a higher surface area and better colloidal dispersion than solid MnO2 nanoparticles. Xanthan gum (as a dispersant) was proven to improve colloidal dispersion of these hollow nanoparticles and were used for further cell studies. In this study, cancer and healthy cells were treated with coated hollow nanoparticles, and the studies indicate that this novel nanoparticle can internalize cells. Particle aggregation has shown to inhibit cell growth. Further studies with this novel hollow nanoparticle may lead to a groundbreaking solution to new drug delivery systems for cancers or other applications.
Silver nanoparticle on aluminum mirror: active spectroscopy and decay rate enhancement
Authors: Kurochkin N S , Eliseev S P , Gritsienko A V , Sychev V V , Vutukhnovsky A G
Published: September 2020

Recent advances in nanotechnology and optics have paved the way for new plasmonic devices. One of them are nanopatch antennas that are simple and, at the same time, effective devices for localizing the electromagnetic field on a scale of less than 10 nm and can be used in photonic integrated circuits as effective sources of photons, including single-photon sources. In the present study, we investigate the radiative characteristics of a submonolayer of colloidal CdSe/CdS quantum dots that form island structures in a resonator: a cubic silver nanoparticle on an aluminum mirror. For detecting plasmonic nanoparticles on glass or metal surfaces, we propose a new technique involving a tunable laser and a confocal microscope. We provide a comparative study of the luminescence enhancement factors for QDs in the NPAs upon off-resonance excitation and at a wavelength close to the resonance; a significant difference in the luminescence enhancement factors (by order of magnitude) is demonstrated. A 60-fold reduction in the spontaneous emission time, as well as an increase in the radiation intensity by a factor of 330, has been obtained in the experiments. The increase in the spontaneous emission rate demonstrated for the quantum dots is explained by the Purcell effect. Full-wave simulations of electromagnetic fields were carried out for the model of the developed nanopatch antenna; luminescence enhancement factors and radiative efficiencies were calculated as well.
A controllable mechanical motion rectifier-based semi-active magnetorheological inerter for vibration control
Authors: Ning Donghong , Christie Matthew Daniel , Sun Shuaishuai , Du Haiping , Li Weihua , Wang Yafei
Published: September 2020

The conventional semi-active variable damping (VD) device can only dissipate the vibration energy, which inherently limits its performance in vibration control. This paper proposes a novel semi-active inerter concept and develops a prototype with magnetorheological (MR) dampers, which can store the vibration energy in a flywheel and then release it to suppress vibration. The new idea is inspired by a variable inertance (VI) device, which has a VD device and a passive inerter in serial, and a passive mechanical motion rectifier (MMR), which can convert the reciprocating input into a unidirectional output. The controllable MMR (CMMR) applies two VD devices to replace the two one-way roller clutches in the MMR. By equipping the CMMR, the semi-active inerter gets more controllability than the original VI device because it can switch the torque and motion transmitting routes between the device terminals and the flywheel in it. The frequency-domain analysis validates the versatile of the semi-active inerter, which can work in VD and VI modes. The test results of the semi-active MR inerter prototype are used to identify the device parameters, which are applied for the control simulation. The semi-active MR inerter in CMMR mode has the best torque tracking performance with a given test condition, and it has a 20.13% improvement than in the VD mode. Then, a seat suspension with the semi-active MR inerter is applied to validate the effectiveness of the device in vibration control. The results show that the vibration reduction of the seat suspension in the CMMR mode is 39.3% higher than in the VD mode, which indicates a significant improvement of ride comfort. The new concept of the semi-active device has excellent potential in vibration control and is promising in practical applications.
Deep learning for impact detection in composite plates with sparsely integrated sensors
Authors: Damm Andreas M , Spitzmüller Claudio , Raichle Andreas T S , Bühler Andre , Weißgraeber Philipp , Middendorf Peter
Published: September 2020

In this paper, both location and energy of impacts on an anisotropic carbon fiber reinforced plate (CFRP) are detected with the help of deep learning. We introduce sparse low-cost sensor array integration in CFRP plates that allows for structural monitoring of lightweight structures. Using a resin transfer moulding process microelectromechanical systems (MEMS) and piezoelectric transducers (PZT) sensors are integrated into CFRP plates. We developed an automated test bench to perform weight drop impact loadings with impact energies ranging between 0.22–0.56 mJ on a 1 × 1 cm2-grid with 441 locations. The obtained sensor signals were processed by means of a short-time fourier transformation and used as input for the training of a deep learning model. This model was implemented with a convolutional neural network. To accelerate the training phase we introduce a coarse analytical model that generates artificial sensor signals we use for pretraining of the neural network. Yielding high prediction accuracies of 99.82% and 98.68% for a correct classification of impact location and energy, respectively, the capability of the proposed approach was demonstrated. Despite their limited resolution the low-cost MEMS accelerometers were able to correctly locate an impact and its energy with 99.76% and 97.04%, respectively. The pretraining led to an increased robustness of the training process. Additionally, for the case of PZT sensors, it also reduced the number of required epochs for convergence significantly.
Development and damping properties of a seismic linear motion damper with MR fluid porous composite rotary brake
Authors: Nakano Masami , Yang Jian , Sun Shuaishuai , Totsuka Atsushi , Fukukita Akira
Published: September 2020

The particle sedimentation of the dispersed particles in magnetorheological (MR) fluids when off-working has been a challenging problem, causing adverse effect to their practical applications. In order to solve this problem, ‘MR fluid porous composite’ made of porous materials impregnated with MR fluid has been fabricated in this work. Its effect to prevent the particle sedimentation has been proved through contrast experiment. Its MR effect has also been measured and verified using a hand-made oscillatory rheometer. Utilizing the MR fluid porous composite, a small-scale seismic linear MR damper has been developed. The unique design of this seismic linear MR damper has enabled it to convert the linear motion (damping force) of the MR damper to the rotations (braking torque) of the MR brake with almost no transmission loss. The damping properties of the developed small-scale seismic MR damper were investigated experimentally to be found that the design target with the damping force to be 20 kN has been achieved when applying an electric current of 0.5 A. Then a theoretical model was derived to estimate the damping force. The simulation results demonstrate that the proposed model is good at describing the properties of the seismic linear MR damper.
A twist piezoelectric beam for multi-directional energy harvesting
Authors: Hu Guobiao , Liang Junrui , Lan Chunbo , Tang Lihua
Published: September 2020

This paper develops a twist beam for multi-directional energy harvesting using piezoelectric transduction. The working principle of the multi-directional ability is explained by the theory of a pre-twisted beam. A simulation study is performed for concept verification and revealing the potential advantages of the proposed twist-beam vibration energy harvester (VEH). A physical prototype is fabricated and an experimental study is conducted to evaluate the actual performance of the proposed twist-beam VEH for validation. The results show that for the excitation comes from any direction in the plane in parallel with the beam cross-section, the proposed twist-beam VEH can produce a substantial amount of power. The optimal resistance is independent of the excitation direction. Moreover, it is found that the relationships between the output voltage amplitude and the excitation direction are different for the cases around the first and second resonances of the twist-beam VEH. The underlying physics behind this phenomenon is that the dominant motion of the two resonant modes are contrarily different. In addition, the experimental study shows that the first two natural frequencies of the prototyped twist-beam VEH are 22.37 and 41.47 Hz, respectively, which are much closer to each other as compared with those of a conventional plain beam. This feature benefits multi-modal energy harvesting within a targeted frequency range. The prospects regarding further optimization of the proposed twist-beam VEH are discussed.
Strong flux pinning and anomalous anisotropy of Sr0.6K0.4Fe2As2 superconducting tapes
Authors: Lin He , Dong Chiheng , Pan Xifeng , Yao Chao , Zhang Xianping , Zhao Yong , Ma Yanwei
Published: September 2020

A comprehensive study on the resistivity, magnetization and microstructure is carried out to understand the superconductivity and flux pinning behavior of hot-pressed Sr0.6K0.4Fe2As2 tapes. The Sr0.6K0.4Fe2As2 tapes possess excellent properties of high T
c = 36.2 K, large transport J
c of ∼105A cm−2 at 10 T and 4.2 K, and high pinning potential U
0/k
B with small field-dependence, demonstrating a great potential in high-field applications. The magnetic J
c at various temperatures and flux pinning mechanism are exhibited for both B//ab and B//c directions. Notably, a point pinning in combination with surface pinning appears in our samples, resulting in a strong flux pinning force. And the characteristic ratio B
irr
//c(0 K)/B
irr
//ab(0 K) is as low as 1.2, indicating that the vortex pinning abilities are nearly isotropic. Further transmission electron microscope characterization reveals that the anomalous pinning behavior is originated from the largely increased small-sized defects and the morphological differences along two directions. These positive results indicate that tailoring the pinning characteristic by creating micro-defects is crucial to improving the J
c value and suppressing the anisotropy in iron pnictides.
Target finding in fibrous biological environments
Authors: Gomez David , Teomy Eial , Lesman Ayelet , Shokef Yair
Published: September 2020

We use a lattice model to study first-passage time distributions of target finding events through complex environments with elongated fibers distributed with different anisotropies and volume occupation fractions. For isotropic systems and for low densities of aligned fibers, the three-dimensional search is a Poisson process with the first-passage time exponentially distributed with the most probable finding time at zero. At high enough densities of aligned fibers, elongated channels emerge, reducing the dynamics dimensionality to one dimension. We show how the shape and size of the channels modify the behavior of the first-passage time distribution and its short, intermediate, and long time scales. We develop an exactly solvable model for synthetic rectangular channels, which captures the effects of the tortuous local structure of the elongated channels that naturally emerge in our system. For arbitrary values of the nematic order parameter of fiber orientations, we develop a mapping to the simpler situation of fully aligned fibers at some other effective volume occupation fraction. Our results shed light on the molecular transport of biomolecules between biological cells in complex fibrous environments.
Chaos and regularity of radionuclides with maximum likelihood estimation method
Authors: Majarshin A Jalili , Sabri H , Mobarakeh S K Mousavi , Pan Feng , Luo Yan-An , Zhang Yu , Draayer Jerry P
Published: September 2020

In this study, we considered the fluctuation properties of some energy levels of even and odd mass radionuclides, which are used in complex phenomena. Different sequences are prepared by using all the available experimental data and analyzed by using the maximum likelihood estimation technique to get the chaoticity parameter of Abul-magd distribution. The dependence of chaoticity degrees of different radionuclides to their mass regions, their decay modes, and also their physical half-lives are studied. Our results show more chaotic behavior of odd-mass radionuclides in comparison with even–even mass and also the most Poisson-like behavior for even–even mass in the A > 150 mass region. The results offer the most regular behavior for long-lived, even mass radionuclides in comparison to other categories of half-lives. Also, we got an obvious difference between the chaoticity degrees for nuclei which undergo β
+ decay in comparison with radionuclides which show electron capture mode.
Fault Diagnosis of Multi-level Principal Component Space Based on High-Dimensional Feature Representation
Authors: Zhang Caixia , Hu Shaolin , Guo Jing , Wang Xiangdong
Published: September 2020

Due to the influence of space equivalent representation and pattern composition, traditional principal component analysis (PCA) is faced with challenges in identifying small faults. This paper proposes a fault diagnosis method is proposed based on multi-levels principal component space based on high-dimensional feature representation. Firstly, based on the original PCA, the dimensions are expanded first and then reduced, so that the information that cannot be expressed in the original space is fully expressed. This method further divides the principal element space based on the eigenvalues, and projects the occurrence of the event and the size of the identification abnormality according to the projection to different sub-spaces. Compared with the usual fault detection methods, simulations verify that this algorithm can effectively measure the level of faults and improve the correct detection rate of minor faults.
Motion Retargeting for Virtual Human Based on Vector Features of Lower Limbs
Authors: Qu Shi , Liu Jianxun , Xu Tinxin , Ma Liang
Published: September 2020

In view of the contradiction that limited motion data can not meet the requirements of rich and changeable motion, motion reuse technology emerges as the times require, which can drive different human skeleton models with the same motion data to generate corresponding motion. However, when the motion data is used to drive the human models with different heights and bone proportions, motion deformation often occurs. In order to solve this problem, the concept of human lower limb vector is proposed in this paper. By analyzing human motion, it is pointed out that the lower limb vector can maintain the main characteristics of motion, and then a human motion redirection method based on the invariance of lower limb vector feature is proposed. This method can redirect the motion data from the original bone model to the target bone model with different bone length ratio, while maintaining the main characteristics of the original motion. The experimental results show that this method has good motion redirection effect and fast computational efficiency.
Bearing-Only Target Tracking Based on Piecewise Backward Smoothing Kalman Filter
Authors: Zheng Yi , Wang Mingzhou
Published: September 2020

In order to solve the problem that the Unscented Kalman Filter algorithm is sensitive to the initial value selection and the noise is easy to expand the error in the recursive process, a piecewise backward smoothing Kalman filter method is proposed in this paper. To reduce the influence of noise, the observation data is optimized in sections, and the forward and reverse use of historical data is increased. The simulation results under different initial distance error, different observation angle variance and different initial velocity error show that the proposed method is effective in underwater bearings only target tracking, and the effect of Unscented Kalman filter is obviously improved, the estimation error is greatly reduced, and the estimation accuracy and stability are improved.
Research on the Reconstruction and Parameterization of Virtual Costume Draping Mannequin in OpenGL Environment
Authors: Wang Xiaobo , Qian Xiaoming , Wang Lijing
Published: September 2020

In the 3D virtual design of clothing, the accuracy of virtual mannequin will significantly affect the fitness of the final garment. At the same time, parameterized mannequin can also improve the efficiency and effect of virtual clothing design. The traditional mannequin modeling method has been improved and the reconstruction and parameterized deformation of virtual costume draping mannequin has been realized in OpenGL environment. The parameterized reconstruction process of mannequin is mainly divided into four parts, namely the establishment of the basic mannequin, the reading of the model data, the parameterized deformation of the grid model and the rendering and drawing of the modal data. Finally, the new parameterized virtual human platform is built and the interactive interface is developed. And the virtual human mannequin can be edited and previewed in real time. The modeling result shows that the parametric reconstruction of the virtual draping mannequin is effective and can be applied to virtual costume designing and virtual fitting system.
Research on the Construction and Operation of the Statistical Analysis System of Cultural Tourism Industry of Shenyang
Authors: Zheng Xinna , Zhou Caiying
Published: September 2020

This paper analyses the development status of the cultural tourism industry in Shenyang by extracting Shenyang’s cultural tourism industry data, establishing a statistical index system for the development of Shenyang tourism industry based on big data tools, and uses big data tools to collect massive amounts of data and break the traditional data sample size. Based on the big data mathematical model, the tourism market in Shenyang was predicted and analysed, and the bottlenecks of small, time delay and low accuracy were obtained. Finally, it proposes to improve the management strategy of Shenyang’s cultural tourism industry, enhance the marketing strategy of cultural travel, strengthen the strategy of cultural travel services, and promote the high-quality development of the cultural tourism industry in Shenyang.
A 3D Design System of Skirt Profile Based on OpenGL
Authors: Xu Jun , Wang Xiaobo
Published: September 2020

Personalized customization is inseparable from effective communication between designers and consumers, which is often aided by 3D software. Based on the OpenGL graphics interface, this paper studies and developed a three-dimensional interactive skirt design system. And This system can help designers and consumers quickly agree on the skirt profile and record the profile parameters. What’s more, it can help designers design and produce clothes that are more in line with consumers’ needs. The research process can be divided into four parts: the establishment of the skirt point cloud model, the triangular meshing of the point cloud model, the rendering of the triangular meshing model, and the development of the interactive interface. The design of skirt length, contour, and pleats can be parametric now with the realistic virtual visual effect. Therefore, this paper provides new ideas and methods for achieving the “what you see is what you get” skirt design concept.
Enhancing Deep Learning-Based Multi-label Text Classification with Capsule Network
Authors: Yan Siyi
Published: September 2020

Given a piece of text, multi-label text classification (MLTC) is designed to mark the most relevant one label or multiple labels for the text. Most of the existing MLTC models use convolutional neural network (CNN) as feature extractor, but CNN will lose information when dealing with MLTC task. In this paper, we explore the CNN combined with capsule network for MLTC. We use capsule network instead of pool layer in CNN to extract information related to classification results in high-dimensional features. We also explore the way of combining recurrent neural network (RNN) and CNN to model the characteristics of time and space for capsule network to complete classification. In two open MLTC datasets, our model achieves the better results as the baseline system, which shows the effectiveness of the combination of capsule network and CNN for MLTC.
Cauliflower Seedling Recognition Using Stereo Vision and K-Medoids Algorithm under Weedy Conditions
Authors: Ge Luzhen , Tan Yuzhi
Published: September 2020

The natural field environment is unstructured where the illumination conditions are uneven, the soil background is complex and changeable. Also, the improper of field management is likely to cause weeds whose colour and shape are similar to crops. Those factors make it hard to identify crops quickly and stably by traditional 2D image processing technologies. So the cauliflower seedling recognition method using binocular stereo vision and K-medoids was proposed in this paper. For the disparity map the Sum of Squared Differences (SSD) algorithm was used in the step of stereo matching. For the cauliflower seedling recognition the K-medoids algorithm was applied in the step of clustering. The experiment results showed that the average operation time of the SSD algorithm was 190ms. The real-time performance and matching effect of the SSD algorithm were superior to Belief Propagation algorithm (BP) and Dynamic Programming algorithm (DP). The average running time of the proposed method for processing the left image and its corresponding right images was 379ms, which meet the real-time requirements. The correct recognition rate of the method proposed was 98.75% of 240 pairs of cauliflower seedling images.