bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen-doped graphene supported Ni as an efficient and stable catalyst for levulinic acid hydrogenation
Authors: Ding Qianqian , Wang Yuan , Ma Liang 
Published: April 2021

Abstract
Transforming levulinic acid (LA) to γ-valerolactone (GVL) is a significant route for converting biomass into valuable chemicals. The development of an efficient and robust heterogeneous catalyst for this reaction has aroused great interest. In this work, nitrogen-doped graphene (NG) supported nickel (Ni) based heterogeneous catalyst with excellent activities was successfully synthesized. The Ni/NG catalyst shows outstanding performance for hydrogenation of LA to GVL at a relatively low temperature of 140 °C, which is superior to most of reported heterogeneous catalysts. Further investigations indicate Ni nanoparticles are the active sites and the NG also plays an indispensable role. The catalytic performance is highly depended on the crystallinity, particles sizes and electronic structure of Ni in Ni/NG catalyst, which can be optimized by nitrogen doping. This work affords a new route for designing robust and excellent heterogeneous catalysts by doping method to optimize the support.
Multi-level aggregation of conjugated small molecules and polymers: from morphology control to physical insights
Authors: Li Qi-Yi , Yao Ze-Fan , Wang Jie-Yu , Pei Jian 
Published: April 2021

Abstract
Aggregation of molecules is a multi-molecular phenomenon occurring when two or more molecules behave differently from discrete molecules due to their intermolecular interactions. Moving beyond single molecules, aggregation usually demonstrates evolutive or wholly emerging new functionalities relative to the molecular components. Conjugated small molecules and polymers interact with each other, resulting in complex solution-state aggregates and solid-state microstructures. Optoelectronic properties of conjugated small molecules and polymers are sensitively determined by their aggregation states across a broad range of spatial scales. This review focused on the aggregation ranging from molecular structure, intermolecular interactions, solution-state assemblies, and solid-state microstructures of conjugated small molecules and polymers. We addressed the importance of such aggregation in filling the gaps from the molecular level to device functions and highlighted the multi-scale structures and properties at different scales. From the view of multi-level aggregation behaviors, we divided the whole process from the molecule to devices into several parts: molecular design, solvation, solution-state aggregation, crystal engineering, and solid-state microstructures. We summarized the progress and challenges of relationships between optoelectronic properties and multi-level aggregation. We believe aggregation science will become an interdisciplinary research field and serves as a general platform to develop future materials with the desired functions.
Data-driven sliding mode control of shape memory alloy actuators with prescribed performance
Authors: Liu Mingfang , Zhao Zhirui , Hao Lina 
Published: April 2021

Abstract
This paper proposes a data-driven sliding mode control (SMC) method with tracking error constraint for a shape memory alloy (SMA) actuated system. More specifically, a new SMC method with prescribed performance is investigated by adopting the equivalent dynamic linearization technique and a novel transformed error algorithm to guarantee that the tracking error can converge into a preassigned region. Meanwhile, the proposed control method can effectively ensure the convergence rate and the steady-state error within a prescribed bound, merely depending on the input/output data without implicit or explicit information of the systems, which is more valuable for the practical application. The presented control method has been implemented on an SMA actuated system successfully and experimental results have shown that the proposed control is easily applicable and highly precise. In addition, the tracking error of the SMA actuated system can be constrained in a preassigned domain by the proposed control method.
Analytical modeling of one-dimensional resonant asymmetric and reciprocal acoustic structures as Willis materials
Authors: Groby Jean-Philippe , Malléjac Matthieu , Merkel Aurélien , Romero-García Vicente , Tournat Vincent , Torrent Daniel , Li Jensen 
Published: April 2021

Abstract
As building blocks of acoustic metamaterials, resonant scatterers have demonstrated their ability to modulate the effective fluid parameters, which subsequently possess extreme properties such as negative bulk modulus or negative mass density. Promising applications have been shown such as extraordinary absorption, focusing, and abnormal refraction for instance. However, acoustic waves can be further controlled in Willis materials by harnessing the coupling parameters. In this work, we derive the closed forms of the effective parameters from the transfer matrix in three asymmetric and reciprocal one-dimensional resonant configurations and exhibit the differences in terms of coupling coefficients. The way in which Willis coupling occurs in spatially asymmetric unit cells is highlighted. In addition, the analysis shows the absence of odd Willis coupling for reciprocal configurations. These effective parameters are validated against experimental and numerical results in the three configurations. This article paves the way of a novel physical understanding and engineering use of Willis acoustic materials.
Quantum manipulation through finite fluctuations for a generalized parametric oscillator using a lie algebra representation
Authors: Beus T , Van Huele J F , Berrondo M 
Published: April 2021

Abstract
In this paper, we focus on the effects of temporally compact fluctuations on the parameters m(t) (mass),

ω
(
t
)

(frequency), and

γ
(
t
)

(spatial dilation coefficient), for the generalized Caldirola-Kanai Hamiltonian. We propose an algorithm such that given control over the timing of repeated compact fluctuations, one can produce any time-evolution associated with complete parameter control of the generalized Caldirola-Kanai Hamiltonian. Computational simplicity is achieved in this endeavor using a faithful representation of the Hamiltonian’s associated Lie algebra. Further simplification occurs as a result of using unitarity conditions for the time-evolution operator. We apply our analysis to the effects of Dirac delta fluctuations in mass and frequency, both separately and simultaneously. We also numerically demonstrate control of the generalized Caldirola-Kanai system for the case of timed Gaussian fluctuations in the mass term. Furthermore, we use the faithful Lie algebra representation to show that any unitary evolution of this generalized Caldirola-Kanai system is given by the squeeze operator multiplied with a phase factor. We also show that the classical evolution of a probabilistic Gaussian phase space distribution and the evolution of the Wigner function of a coherent state in the quantum Caldirola-Kanai system are identical.
Study of engine-oil based CNT nanofluid flow on a rotating cylinder with viscous dissipation
Authors: Khan Masood , Sarfraz Mahnoor , Ahmed Awais , Malik M Y , Alqahtani Ali S 
Published: April 2021

Abstract
An axisymmetric viscous carbon nanotube (CNT) nanofluid flow exterior to a rotating circular cylinder of radius a
0 along with viscous dissipation and magnetohydrodynamic (MHD) is considered here. The two-phased Buongiorno’s model is employed to observe the thermal energy transport in nanofluid with engine-oil as a background fluid and two distinct nanoparticles, i.e., single-walled (SWCNTs) and multi-walled (MWCNTs). The flow is driven because of the torsional motion and stretching of the cylinder along the z-direction, which constitutes the axial pressure gradient. It is seen that in the presence of a magnetic field, the axially dependent swirling motion of the cylinder creates a light transverse flow in the meridional plane, which is the principal cause for the wall jet phenomenon on the axial axis. The function computing the numerical solution is bvp5c, which is available in Matlab®. It is noted that for both SWCNTs/MWCNTs cases, thermal and mass transport coefficients are decreasing function of Prandtl and Schmidt numbers, respectively. However, they are augmented due to the presence of strong Lorentz force. The values for wall stress parameters (WSPs) are determined as a function of a magnetic parameter for 0.01 ≤ Re ≤ 102 (where Re is Reynolds number). It is also perceived that the axial WSP decreases due to an increase in values of Re, but an increase in numerical values of azimuthal WSP and Nusselt number is noticed.
Computational analysis of fuzzy fractional order non-dimensional Fisher equation
Authors: Ahmad Shabir , Ullah Aman , Ullah Abd , Akgül Ali , Abdeljawad Thabet 
Published: April 2021

Abstract
In recent decades, fuzzy differential equations of integer and arbitrary order are extensively used for analyzing the dynamics of a mathematical model of the physical process because crisp operators of integer and arbitrary order are not able to study the model being studied when there is uncertainty in values used in modeling. In this article, we have considered the time-fractional Fisher equation in a fuzzy environment. The basic aim of this article is to deduce a semi-analytical solution to the fuzzy fractional-order non-dimensional model of the Fisher equation. Since the Laplace-Adomian method has a good convergence rate. We use the Laplace- Adomian decomposition method (LADM) to determine a solution under a fuzzy concept in parametric form. We discuss the convergence and error analysis of the proposed method. For the validity of the proposed scheme, we provide few examples with detailed solutions. We provide comparisons between exact and approximate solutions through graphs. In the end, the conclusion of the paper is provided.
Perturbations in a scalar field model with virtues of ΛCDM
Authors: Sinha Srijita , Banerjee Narayan 
Published: April 2021

Abstract
In the era of precision cosmology, the cosmological constant Λ gives quite an accurate description of the evolution of the Universe, but it is still plagued with the fine-tuning problem and the cosmic coincidence problem. In this work, we investigate the perturbations in a scalar field model that drives the recent acceleration in a similar fashion that the cosmological constant does and has the dark energy (DE) density comparable to the dark matter (DM) energy density at the recent epoch starting from arbitrary initial conditions. The perturbations show that this model, though it keeps the virtues of a ΛCDM model, has a distinctive qualitative feature, particularly it reduces the amplitude of the matter power spectrum on a scale of 8 h-1 Mpc, σ8 at the present epoch.
Neutrino-assisted early dark energy: theory and cosmology
Authors: Carrillo González Mariana , Liang Qiuyue , Sakstein Jeremy , Trodden Mark 
Published: April 2021

Abstract
The tension between measurements of the Hubble constant obtained at different redshifts may provide a hint of new physics active in the relatively early universe, around the epoch of matter-radiation equality. A leading paradigm to resolve the tension is a period of early dark energy, in which a scalar field contributes a subdominant part of the energy budget of the universe at this time. This scenario faces significant fine-tuning problems which can be ameliorated by a non-trivial coupling of the scalar to the standard model neutrinos. These become non-relativistic close to the time of matter-radiation equality, resulting in an energy injection into the scalar that kick-starts the early dark energy phase, explaining its coincidence with this seemingly unrelated epoch. We present a minimal version of this neutrino-assisted early dark energy model, and perform a detailed analysis of its predictions and theoretical constraints. We consider both particle physics constraints — that the model constitute a well-behaved effective field theory for which the quantum corrections are under control, so that the relevant predictions are within its regime of validity — and the constraints provided by requiring a consistent cosmological evolution from early through to late times. Our work paves the way for testing this scenario using cosmological data sets.
Steady-state teleportation fidelity and Bell nonlocality in dissipative environments
Authors: Xie Yu-Xia 
Published: April 2021

Abstract
We investigate quantum teleportation and Bell nonlocality for two channel qubits coupled via the Heisenberg interaction and subject to two independent dissipative environments. Compared with the case of two uncoupled qubits, it is shown that the interaction Hamiltonian is beneficial for enhancing the teleportation fidelity and Bell nonlocality, and remarkably, it can also be used to create nonclassical teleportation fidelity and Bell nonlocality even from the initial product states. Moreover, the interaction Hamiltonian guarantees the generation of steady-state nonclassical teleportation fidelity, which is independent of the initial state and therefore one can take any state as the initial channel state.
Real-time, precise, rapid and objective visual acuity assessment by self-adaptive step SSVEPs
Authors: Zheng Xiaowei , Xu Guanghua , Du Chenghang , Yan Wenqiang , Tian Peiyuan , Zhang Kai , Liang Renghao , Han Chengcheng , Zhang Sicong 
Published: April 2021

Abstract

Objective. This study aimed to explore an online, real-time, and precise method to assess steady-state visual evoked potential (SSVEP)-based visual acuity more rapidly and objectively with self-adaptive spatial frequency steps. Approach. Taking the vertical sinusoidal reversal gratings with different spatial frequencies and temporal frequencies as the visual stimuli, according to the psychometric function for visual acuity assessment, a self-adaptive procedure, the best parameter estimation by sequential testing algorithm, was used to calculate the spatial frequency sequence based on all the previous spatial frequencies and their significance of the SSVEP response. Simultaneously, the canonical correlation analysis (CCA) method with a signal-to-noise ratio (SNR) significance detection criterion was used to judge the significance of the SSVEP response. Main results. After 18 iterative trails, the spatial frequency to be presented converged to a value, which was exactly defined as the SSVEP visual acuity threshold. Our results indicated that this SSVEP acuity had a good agreement and correlation with subjective Freiburg Visual Acuity and Contrast Test acuity, and the test–retest repeatability was also good. Significance. The self-adaptive step SSVEP procedure combined with the CCA method and SNR significance detection criterion appears to be an alternative method in the real-time SSVEP acuity test to obtain objective visual acuity more rapidly and precisely.
How to build a fast and accurate code-modulated brain-computer interface
Authors: Ramírez Torres Juan Antonio , Daly Ian 
Published: April 2021

Abstract

Objective. In the last decade, the advent of code-modulated brain-computer interfaces (BCIs) has allowed the implementation of systems with high information transfer rates (ITRs) and increased the possible practicality of such interfaces. In this paper, we evaluate the effect of different numbers of targets in the stimulus display, modulation sequences generators, and signal processing algorithms on the accuracy and ITR of code-modulated BCIs. Approach. We use both real and simulated electroencephalographic (EEG) data, to evaluate these parameters and methods. Then, we compared numerous different setups to assess their performance and identify the best configurations. We also evaluated the dependability of our simulated evaluation approach. Main results. Our results show that Golay, almost perfect, and deBruijn sequence-based visual stimulus modulations provide the best results, significantly outperforming the commonly used m-sequences in all cases. We conclude that artificial neural network processing algorithms offer the best processing pipeline for this type of BCI, achieving a maximum classification accuracy of 94.7% on real EEG data while obtaining a maximum ITR of 127.2 bits min−1 in a simulated 64-target system. Significance. We used a simulated framework that demonstrated previously unattainable flexibility and convenience while staying reasonably realistic. Furthermore, our findings suggest several new considerations which can be used to guide further code-based BCI development.
Preliminary spectral matching analysis of RDE site at Serpong Indonesia
Authors: Yuliastuti  , Hakim E E Al , Wicaksono A B , Iswanto E R , Syaeful H , Sunarko  
Published: April 2021

Abstract
In concurrent with the plan to build small experimental power reactor at Serpong site, site specific response spectra evaluation is required to ensure the reactor safety. Site response spectra involved the spectral matching analysis which incorporates the seismic characteristics of the site and the design spectra. This paper presented the preliminary spectral matching analysis of selected natural earthquake records by comparing Al Atik & Abrahamson (2006) algorithm and Hancock et. al (2010) algorithm. The natural earthquake records were selected based on their similarity of their characteristics such as magnitude, distance resulting from deagregation analysis and site-specific conditions. Two subset periods were employed in the spectral matching analysis. Fourier spectrum and wave envelope analysis showed that both algorithms have maintained the original non-stationary characteristics. PGA, PGV and PGD values resulting from spectral matching have significant changes from the original as an implication of accelerogram amplitude scaling. From the spectral matching analysis, KAU083 record resulting from Hancock et. al (2006) algorithm has yielded the best matched to the target spectra compared to other selected records.
Numerical simulation and analysis of nominal wake of displacement ship
Authors: Li Xiang , Dong Jinshuang , Sun Shuai 
Published: April 2021

Abstract
In order to analyze the performance of ship resistance and nominal wake of container ship and bulk carrier, the method of CFD was used to compare the influence factors such as the distribution pattern of grids and turbulence models, and the calculation results were compared with experimental values. The predicted results show that the ship resistance calculated by the model of Volume of Fluid achieves a good agreement with experimental data. An optimal scheme for computing the nominal wake was got by analyzing the results of three grid schemes and two turbulence models. The container ship’s axial nominal wake, tangential nominal wake and radial wake has the same variation trend with the experimental data, so it validates the feasibility of this method set in this paper. Thenominal wake of a bulk carrier took as an example was computed and the “hooked” wake was also got very well. At the same time, the cause of the “hooked” wake was got a good analysis.
The Effect Of Adhesive Variations (Starch, Liquid Smoke, and Used Oil), And The Form Of Rice Husk Briquette (Cylinder and Block) On The Performance Of The Gasification TLUD Method
Authors: Wijianto  , Sarjito  , Aklis Nur , Subroto  , Sulistyanto Amin 
Published: April 2021

Abstract
This research aimed to determine the effect of the adhesive types on rice husk briquettes in the TLUD gasification process. The types of adhesive used are starch, tar, and used oil. Rice husk briquettes have varied in two forms, namely cylindrical and block shapes. Each variation has a diameter of 1 inch and a side of 1 inch as well. Rice husk in uniform meshing with 20 mesh size. The Gasification process uses rice husk briquette as fuel. The next step is to insert 3 kg of briquettes into the gasification cylinder. Then ignited to start the gasification process. The type of gasification furnace used is the TLUD type. That is an updraft type gasification with initial ignition on the upper surface of the briquette fuel. Data collection was carried out to determine how much the sufficient flame temperature was and how long the gasification process’s adequate flame time took place and determine the briquettes’ quality by testing the water boiling test. These test results show that rice husk briquettes with used oil adhesive variations are better than other adhesive variations, reach an average temperature of 755°C, and boil 2 liters of water in 6 minutes.
Analytical Hierarchy Process (AHP) to Determine the Sustainable Drainage System Used for Flood Management in Central Karanganyar Regency
Authors: Kurnianingsih O , Solikin Mochamad , Pudyastuti P , Sunarjono S , Hidayati N 
Published: April 2021

Abstract
A sustainable drainage system is one of the right methods in dealing with floods in cities, including in Karanganyar. The parameters of technology selection problems planned with the Analytic Hierarchy Process (AHP) are technical, economic, environmental, social/cultural, and technology: infiltration wells with drainage channels, rainwater harvesting with drainage channels, and dry swale. Rainfall data is used in this research. The area used is planning, budget planning, and AHP method steps with hierarchical compilation, pairwise comparisons, priority values, testing consistency, and data obtained from technology selection questionnaires filled with related institutions. The most influential criteria in the choice drainage system technology are environmental criteria 49%, technical 33%, economy 12%, and social/cultural 5%. The priority technology is rainwater harvesting with drainage channels with a percentage of 37.3%, infiltration wells with drainage channels 35.2%, and dry swale 27.4%.
Terraced Wetland Construction of Liquid Waste Pollution Countermeasures from Tofu Industry (Case Study of Tofu Industry in Mojosongo, Surakarta)
Authors: Karnanta Sunandar Priya , Solikin Mochamad , Purnama Herry 
Published: April 2021

Abstract
Tofu is a food that every level of society liked because of its low price and many nutrient contents. Tofu making uses a lot of water for sorting, immersion, boiling, and filtering to produce enough liquid tofu waste. The problem that most rises related to the tofu industry is the problem of waste processing. If the tofu waste is disposed of directly into the river, it will affect the life of biota and pollute the environment. Therefore facility is needed for wastewater treatment that can be used continuously with a wetland construction system. The A filter composition consists of sand, charcoal, and zeolite. The B composition consists of soil, palm fiber, sand, charcoal, and zeolite with cattail plants (Thypa latifolia). C composition consists of soil, palm fiber, sand, charcoal, and zeolite with cattail plant (Thypa latifolia) and Phragmites australis. The three compositions are then analyzed in filtering the tofu industrial wastewater. The best result of tofu liquid waste processing is using the C wetland composition construction; pH with a value of 6.7 BOD with a value of 146mg/L, COD 338mg/L, TSS 123mg/L.
Dynamic Model and Equilibrium Stability of an Inverted Double Pendulum System
Authors: Susanto Erwin , Yuwono Sigit 
Published: April 2021

Abstract
Most inverted pendulum types, such as single or double pendulums, translational or rotational, are underactuated, nonlinear, and unstable. To handle this inverted pendulum, much effort has to do, especially in stabilization aspects. An appropriate control strategy based on suitable modeling is the key to stabilization’s handling. Modeling and stabilizing an inverted double pendulum need more complex efforts than those of a single type. The obtained model is indispensable for control design in future works, and the success of the method depends on the accuracy of the developed model. The result showed that the dynamic model is fit enough, and the eigenvalue of the system is unstable, as predicted earlier.