bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative diagnosis of mechanical faults based on generalized fractal dimensions
Authors: Tang Yaochi , Li Kuohao 
Published: February 2021

Abstract
The bearing is an important part of mechanical equipment. Its condition directly influences the operation of the entire mechanical equipment. Faults in bearings may induce fatal disasters and heavy economic losses, in worst-case scenarios. In fault diagnosis, many studies have only proposed the characteristics of faults; however, without standards for quantifying the faults, automated diagnosis could not be realized. Based on the generalized fractal dimensions (GFDs) and the receiver operating characteristic (ROC) curve, this study proposed a method to characterize initial failure trends and quantize the bearing failure standard. The size of GFDs was calculated using the vibration signal measured during the operation of a bearing. The optimal classification model was determined based on the ROC curve as the criterion of damage. The model trained by the signals of the training group was used in the check analysis of the signals of the validation group. The accuracy of this quantitative analysis was validated by experimental results. Finally, three bearings in different positions were diagnosed by this model under the same test conditions, and the effectiveness of the quantitative diagnosis of damage proposed in this study was validated.
Linearization of the lift-off effect for magnetic flux leakage based on Fourier transform
Authors: Wang Jie , Li Erlong , Wu Jianbo , Xu Xianyou 
Published: February 2021

Abstract
In magnetic flux leakage testing, the lift-off effect shows that testing signal voltages vary with lift-off values. This has many adverse effects on detection and evaluation. This paper proposes a novel method for linearization of the lift-off effect in the spatial domain. The spatial analytical expression is obtained through magnetic dipole theory and the Fourier transform method. An analytical method to linearizethe lift-off effect is proposed. Further, the finite-element method and discrete Fourier transform method are applied to linearize the lift-off effect. Experimental studies are also conducted to verify the analytical results. The linear fitting function of the lift-off effect takes the form of Y = AX + B. When the spatial frequency ω is 35 mm−1, the linear fitting results of the simulation and experiment are Y = −0.23596X−2.0268 and Y = −0.23511X + 4.8152. The goodness of fit R2
is 0.9997 and 0.9975. The results show that the lift-off effect can be linearized in the spatial domain. The coefficient A is slightly affected by the defect size. The coefficient B is strongly related to the defect size. We consider these results to be quite significant.
Graphene-reinforced polymer matrix composites fabricated by in situ shear exfoliation of graphite in polymer solution: processing, rheology, microstructure, and properties
Authors: Hussein Arab H , Dong Zhizhong , Lynch-Branzoi Jennifer , Kear Bernard H , Shan Jerry W , Pelegri Assimina A , Tse Stephen D 
Published: February 2021

Abstract
Effective methods are needed to fabricate the next generation of high-performance graphene-reinforced polymer matrix composites (G-PMCs). In this work, a versatile and fundamental process is demonstrated to produce high-quality graphene-polymethylmethacrylate (G-PMMA) composites via in situ shear exfoliation of well-crystallized graphite particles loaded in highly-viscous liquid PMMA/acetone solutions into graphene nanoflakes using a concentric-cylinder shearing device. Unlike other methods where graphene is added externally to the polymer and mixed, our technique is a single step process where as-exfoliated graphene can bond directly with the polymer with no contamination/handling. The setup also allows for the investigation of the rheology of exfoliation and dispersion, providing process understanding in the attainment of the subsequently heat injection-molded and solidified G-PMC, essential for future manufacturing scalability, optimization, and repeatability. High PMMA/acetone concentration correlates to high mixture viscosity, which at large strain rates results in very-high shear stresses, producing a large number of mechanically-exfoliated flakes, as confirmed by liquid-phase UV–visible spectral analysis. Raman spectroscopy and other imaging evince that single- and bi-layer graphene are readily achieved. Nevertheless, a limit is reached at high mixtures viscosities where the process becomes unstable as non-Newtonian fluid behavior (e.g. viscoelastic) dominates the system. Characterization of microstructure, morphology, and properties of this new class of nanostructured composites reveals interesting trends. Observations by transmission electron microscopy, scanning electron microscopy, and helium ion microscopy of the manufactured G-PMCs show uniform distributions of unadulterated, well-bonded, discontinuous, graphene nanoflakes in a PMMA matrix, which enhances stiffness and strength via a load-transfer mechanism. Elastic modulus of 5.193 GPa and hardness of 0.265 GPa are achieved through processing at 0.7 g ml−1 of acetone/PMMA for 1% wt. starting graphite loading when injected into a sample mold at 200 °C. Mechanical properties exhibit 31% and 28.6% enhancement in elastic modulus and hardness, respectively, as measured by nano-indentation.
The ROS-generating photosensitizer-free NaYF4:Yb,Tm@SiO2 upconverting nanoparticles for photodynamic therapy application
Authors: Kowalik P , Kamińska I , Fronc K , Borodziuk A , Duda M , Wojciechowski T , Sobczak K , Kalinowska D , Klepka M T , Sikora B 
Published: February 2021

Abstract
In this work we adapt rare-earth-ion-doped NaYF4 nanoparticles coated with a silicon oxide shell (NaYF4:20%Yb,0.2%Tm@SiO2) for biological and medical applications (for example, imaging of cancer cells and therapy at the nano level). The wide upconversion emission range under 980 nm excitation allows one to use the nanoparticles for cancer cell (4T1) photodynamic therapy (PDT) without a photosensitizer. The reactive oxygen species (ROS) are generated by Tm/Yb ion upconversion emission (blue and UV light). The in vitro PDT was tested on 4T1 cells incubated with NaYF4:20%Yb,0.2%Tm@SiO2 nanoparticles and irradiated with NIR light. After 24 h, cell viability decreased to below 10%, demonstrating very good treatment efficiency. High modification susceptibility of the SiO2 shell allows for attachment of biological molecules (specific antibodies). In this work we attached the anti-human IgG antibody to silane-PEG-NHS-modified NaYF4:20%Yb,0.2%Tm@SiO2 nanoparticles and a specifically marked membrane model by bio-conjugation. Thus, it was possible to perform a selective search (a high-quality optical method with a very low-level organic background) and eventually damage the targeted cancer cells. The study focuses on therapeutic properties of NaYF4:20%Yb,0.2%Tm@SiO2 nanoparticles and demonstrates, upon biological functionalization, their potential for targeted therapy.
Approaching the radiating X-point in SOLPS-ITER modeling of ASDEX Upgrade H-mode discharges
Authors: Senichenkov I Yu , Kaveeva E G , Rozhansky V A , Voskoboynikov S P , Veselova I Yu , Shtyrkhunov N V , Coster D P , Bonnin X 
Published: February 2021

Abstract
In the present paper the ASDEX Upgrade (AUG) experimental trend of reaching the radiating X-point with nitrogen seeding is reproduced by SOLPS-ITER code modeling. In these experiments the whole divertor region below the X-point is cooled down by the impurity radiation if the seeding rate is large enough, and the maximal radiation is registered from the X-point region, or even from the confinement zone above the X-point. It is demonstrated that for constant seeding rate SOLPS-ITER simulations of the intensively seeded AUG discharges result in that the confined plasma goes into the radiation collapse as a certain threshold in seeding rate is exceeded. This threshold value increases with increasing discharge power. No stable regimes with the electron temperature below 5 eV in the confinement zone even above the X-point are achieved in the modeling if the seeding rate is large enough, in contrast to the experiment. However, such a regime may be achieved if the fueling, seeding and pumping rates are changing in time. Since the SOLPS-ITER code can simulate only steady state, another modeling strategy is chosen. The fueling and seeding rates are artificially reduced by 3 orders of magnitude and the impurity content is set to satisfy the condition that the ratio of electrons contribution originating from fuel atoms to ones coming from impurity atoms is about unity. It is suggested that the radial width of the cooled region in the confinement zone is of the order of the scrape-off layer width λ

q
, since it is driven by the same physics leading the energy flux to go from mostly radial to mostly parallel. Under these conditions, the radiative spot above the X-point behaves as the energy sink similarly to the energy sink near the divertor in the conventional regime. In extreme regimes (with large seeding rate), the width of the cold region inside the separatrix may exceed λ

q
, and up to 90% of discharge power can be radiated from the confined region. An estimate of the poloidal length of the radiative spot is suggested as well. Flow patterns of neutrals, deuterium ions, impurities, electric current and heat flows are analyzed for the regimes with intensive X-point radiation. The formation of an electric potential peak above the X-point is observed in the simulations, and the corresponding E × B drift flux appears to give the largest contribution to the main ion and impurity fluxes. This E × B drift flux together with the large ionization source change the parallel velocity with respect to its neoclassical profile. Consequently, the radial E field deviates from the neoclassical one, which might improve the turbulence suppression.
A magnetorheological fluid based planetary gear transmission for mechanical power-flow control
Authors: Christie M D , Sun S , Quenzer-Hohmuth J , Deng L , Du H , Li W H 
Published: February 2021

Abstract
Power transmission for mechanical systems often involves the use of clutching- or dissipative-elements to protect drive systems and provide steady output power. As standard implementations in motor-driven systems, these devices operate passively or in discrete states, providing limited controllability to the power output. This paper presents a magnetorheological-fluid-based differential (planetary) gear transmission which serves to variably couple motor power through a sun gear input to a load affixed to a planet carrier output. This is achieved both rapidly and continuously through controlled slippage between the ring gear of the device and its casing. Compared to conventional MR clutches, the unique functionality of the differential gearbox enables use of an MR brake with lower inertia than an in-line clutch. Through control of current supplied to the energizing electromagnet of brake component of the transmission, simple and reversible governing of output torque and speed is achieved. This behaviour is modelled and verified through testing, showing a 349% variation in brake torque for constant speed tests from the off state to the maximum capacity of the device, with a 262% variation in brake torque under a harmonic input displacement also observed. The versatility of the device demonstrated through PID speed and torque control.
Study of high-order harmonic generation in xenon based on time-dependent density-functional theory
Authors: Romanov A A , Silaev A A , Sarantseva T S , Frolov M V , Vvedenskii N V 
Published: February 2021

Abstract
The high-order harmonic generation (HHG) in xenon is studied by using the time-dependent density-functional theory. The dynamics of all electrons on the outer 4th and 5th atomic shells is considered with subsequent separation of contributions of different atomic orbitals to the HHG amplitude. It is shown that giant enhancement of HHG yield in a spectral region near 100 eV is caused by perturbation of the electron–electron interaction potential induced by recolliding photoelectron wavepacket originated from the 5p
0 orbital. This perturbation leads to the collective oscillations of all orbitals on the 4th shell closely localized in space and strongly interacting with each other. The resulting HHG yield is enhanced by more than an order of magnitude compared with the response of the single 5p
0 orbital. The high accuracy of the numerical results is confirmed by comparing the calculated HHG spectra and photoionization cross-sections with experimental results and an analytical parameterization of the HHG yield.
A class of integro-differential Fokker-Planck equations with space-dependent coefficient
Authors: Fa Kwok Sau 
Published: February 2021

Abstract
Exact solution for the probability distribution function (PDF) in Laplace space is obtained for a class of integro-differential Fokker-Planck equations with different kernels and generic space-dependent diffusion coefficient. Besides, exact solutions for the PDF and n-moment are also obtained for different kernels and a power-law diffusion coefficient; they are analyzed and compared for different kernels.
Systematic study of the Woods-Saxon potential parametersbetween heavy-ions *
Authors: Gan Lin , Li Zhi-Hong , Sun Hui-Bin , Hu Shi-Peng , Li Er-Tao , Zhong Jian 
Published: February 2021

Abstract
Experimental elastic scattering angular distributions of 11B, 12C, and 16O + heavy-ions are used to study the Woods-Saxon potential parameters. Best fitted values of the diffuseness parameters are found for each system, and a linear relationship is expressed between the diffuseness parameters and

. The correlation of the potential depth and radius parameters with

is also revealed within the limitations of the diffuseness parameter formula. Because the incident energies of most of the analyzed reactions are below or around the Coulomb barrier, the energy dispersion relation between the real and imaginary potentials is considered in order to investigate the ratio between the imaginary and real potential well depths, resulting in an expression of

. Within the limitation of the volume integrals calculated with the S

o Paulo potential, parameterized formulas for the depth and radius parameters are obtained. The systematic Woods-Saxon potential parameters derived in the present work can reproduce not only the experimental data of elastic scattering angular distributions induced by 11B, 12C, and 16O but also some elastic scattering induced by other heavy-ions.
Uncertainty in the mutual calibration method for the traceable thickness measurement of ultra-thin oxide films
Authors: Lee Seung Mi , Woo Jin Chun , Kim Tae Gun , Kim Kyung Joong 
Published: February 2021

Abstract
Mutual calibration by a combination of a zero-offset method and a length-unit traceable method has been suggested as a promising approach to determine the traceable thickness of ultra-thin oxide films. However, the measurement uncertainty is somewhat complicated to calculate because the standard uncertainties from the two measurement methods and the linear regression process should be combined. In this study, the mutual calibration method to evaluate the film thickness and uncertainty of ultra-thin oxide films was investigated. The algorithm of the linear regression equation in the mutual calibration method was studied and the uncertainty calculation program for the thickness measurement by mutual calibration was developed. The result will provide an effective and useful guideline to certify the thickness of the ultra-thin oxide film on Si(100) substrate which is used as the gate oxide in the semiconductor devices. The magnitude of the relative expanded uncertainty in the thickness measurement by mutual calibration is in the range from 8.6% to 9.3%.
Evolution of ELMs, pedestal profiles and fluctuations in the inter-ELM period in NBI- and ECH-dominated discharges in DIII-D
Authors: Banerjee Santanu , Mordijck S. , Barada K. , Zeng L. , Groebner R. , Osborne T. , Rhodes T.L. , Snyder P.B. , Grierson B. , Diallo A. 
Published: February 2021

Abstract
In DIII-D, it has been observed that ELM frequency decreases by 40% and ELM spacing becomes more regular in time when heating is changed from pure neutral beam injection (NBI) to predominantly electron cyclotron heating (ECH) in ITER similar shape plasmas. In comparison with the pure NBI discharges, pedestal fluctuations in magnetics and density increase in the ECH-dominated discharges. Recovery of the pedestal profiles like electron density (n
e), temperature (T
e) and pressure (p
e) shows marked differences for these two heating schemes. Average profiles in the last 30% of the ELM cycle show higher T
e, lower n
e, and similar p
e at the pedestal top for the ECH discharge when compared to the NBI discharge. The gradient of T
e (∇T
e) is also steeper at the pedestal in the ECH discharge. Magnetic fluctuations show three distinct modes at 13–116 kHz in the ECH discharges only. n
e fluctuations show two modes evolving in the inter-ELM period of the ECH discharge, a low-frequency (400 kHz) quasi-coherent mode (LFQC) and high-frequency (∼2 MHz) broadband (HFB) fluctuations. Evolution of these modes has marked correspondence with the inter-ELM ∇T
e recovery. A sharp decrease in the D

α
baseline is observed whenever the LFQC weakens and the HFB grows, prior to each large ELM. Transport coefficients obtained from TRANSP show that MTM and/or TEM are plausible candidates for the observed fluctuations. Linear gyrofluid simulation (TGLF) corroborates this characterization. TGLF shows that the linear growth rate of the most dominant mode peaks at ion-scale (k

θ

ρ

s
∼ 0.4) at the pedestal steep gradient and the frequency is in the electron diamagnetic direction. It is proposed that increased fluctuations in the ECH-dominated case, due to increased ∇T
e, caused an increase in fluctuation-driven transport in the pedestal and slowed the pedestal recovery between ELMs, leading to a reduction in the ELM frequency.
The Effect of Cross-linking and Fatty Acid Addition on the Functional Properties and Digestibility of Tapioca Starch
Authors: Oktaviana D , Saepudin E 
Published: February 2021

Abstract
The present work was carried out the effect of cross-linking and fatty acid addition on the functional properties and digestibility of tapioca starch. Tapioca starch was chemically modified using sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) and fatty acid addition used stearic acid (C18). Thermogravimetric analysis showed higher thermal stability for the modified granules compared to the native one. A-type crystalline was formed on native and cross-linking starch, then A-type and V-type crystalline polymorphs were formed between starch and fatty acids. The both modifications decreased solubility, swelling power, paste clarity, viscosity and the dual modification significantly decreased digestibility of tapioca starch.
The improvement of students’ conceptual understandings through the PQ4R aided the 5E learning cycle model on the topic of salts hydrolysis
Authors: Sartika Rody Putra , Hadi Lukman 
Published: February 2021

Abstract
Conceptual understanding is essential for students to be gained during classroom activities. There are various methods to achieve it. This study was conducted to describe the improvement of students’ conceptual understanding of the topic of salt hydrolysis after being taught with the PQ4R aided-5E learning cycle model. To achieve the goal, one shot study was implemented as a study design. As participants, first semester students of the chemistry education department of Tanjungpura University were selected. Data were collected through an achievement test, which comprised two indicators. The indicators used were identifying acid-base properties of salts and determining the pH of salts solutions. The results showed that the improvements were 3.23%, 77.42%, and 19.35%, which was categorized as excellent, average, and poor, respectively. In conclusion, PQ4R aided the 5E learning cycle model successfully improved students’ conceptual understandings.
CuSO4/H2O2-Induce Rapid Polymerization of Dopamine on Cotton Fabric for Oil/Water Separation
Authors: Liang Yuan , Zhaofang DU , Fei Li , Ransheng Zuo , Yan Zhou , Hao Wang 
Published: February 2021

Abstract
CuSO4/H2O2 was used as the oxidation system to induce rapid polymerization of dopamine(DA) which modified the surface of cotton fabric. FTIR analysis showed that polydopamine(PDA) was successfully bonded to the surface of cotton fabric by DA self-polymerization under CuSO4/H2O2 system. The surface of cotton fabric modified by PDA could change from hydrophilicity to hydrophobicity. Compared with traditional dopamine deposition, the cotton fabric modified by rapidly deposited PDA had better hydrophobicity, and which could apply for the oil/water separation. Through the test, the separation efficiencies of modified cotton fabric by rapidly deposited PDA all reached above 96% for three different types of oil/water mixture after three times, indicating that PDA modified cotton under CuSO4/H2O2 condition for oil/water separation had good efficiency and reusability.
Research on the Development and Application of Antibacterial Medical Protective Clothing
Authors: Shi Wang , Shuo Yu , Ning Zhang 
Published: February 2021

Abstract
Nowadays, more diversified and complicated changes have been taking place in viruses and bacteria, so the research and development of medical protective clothing turns out to be increasingly important. An excellent antibacterial performance is one of the basic standards in the medical protection system. By sorting the development history of medical protective clothing, this article analyzes the current application of antibacterial protective clothing in terms of antibacterial materials, processing technology, and technological intelligence, and offers a prospect for the development trends of future protective clothing.
Osteoblast cell viability over ultra-long tricalcium phosphate nanocrystal-based methacrylate chitosan composite for bone regeneration
Authors: Xu Hongyao , Zou Xiangjie , Xia Pengcheng , Huang He , Liu Feng , Ramesh Thiyagarajan 
Published: February 2021

Abstract
Bioceramic morphology plays a crucial role in bone repair and regeneration. It is extensively utilized in bone scaffold synthesis due to its better biological system activity and biocompatibility. Here, ultra-long tricalcium phosphate (UTCP) was synthesized with the assistance of the ultrasonication method. The UTCP was modified as a scaffold by the reinforcement of a methacrylate chitosan (MAC) polymer. The functionality of UTCP, UTCP/MAC, and methotrexate (MTX)-loaded composites was characterized through Fourier transform infrared spectroscopy. The crystalline natures are investigated by x-ray diffraction, and the results show the UTCP crystalline phase is not altered after the reinforcement of the MAC polymer and loading of MTX drugs. The morphological analyses were observed through electron microscopic analysis, and polymer-coated rod structures were observed. The UTCP/MAC composite mechanical stress was increased from 1813 Pa of UTCP to 4272 Pa. MTX loading and release at 79.0% within 3 h and 76.15% at 20 h, respectively, were achieved. The UTCP/MAC and UTCP/MAC/MTX’s osteoblast-like (MG-63) cell viability was investigated, and the MTX-loaded UTCP/MAC composite exhibits good viability behavior up to 96.0% in 14 d. The results confirm the higher compatibility of the composite and profitable cell growth. It may be suitable for bone implantation preparation, and it helps in faster regeneration of bone tissue after in vivo and clinical evaluation.