bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous determination of size and velocity of microspheres in flow by polarization analysis of the scattered light
Authors: Huang Xiaoqun , Bailly Yannick , Lepiller Valérie 
Published: August 2019

Abstract
A particle sizing method based on the analysis of polarization status of light scattered by targeted particles is introduced, with the polarization ratio of scattered light obtained through particle image processing. The optical setup was combined with PIV (Particle Image Velocimetry) for the simultaneous determination of particle velocity field. The presented granulometry and velocimetry method was applied to determine the size distribution of DEHS particles dispersed in ambient air generated by an aerosol generator. With the particle velocity field acquired simultaneously, the size distributions of DEHS particles under different operating pressures obtained from the presented method were compared with standard values provided by the manufacturer and showed a good correspondence, which proved it to be a promising flow field diagnostic technique.
Aerodynamic Characteristics of a Ducted Fan System Based on Momentum Source Method
Authors: Cai Hongming , Ma Guoliang , Li Zhongxin 
Published: August 2019

Abstract
Ducted fan systems have received a considerable attention due to their potential for wide application in both civil and military missions. Compared with isolated fans, the presence of duct can substantially weaken the contraction of fan wake and gives the potential to fly efficiently with high security, compact structure and low noise. Based on the momentum source method (MSM) and the S-A turbulence model, a computational fluid dynamics (CFD) simulation model is established and validated as a reliable tool by comparing with calculation results based on sliding mesh technique. The effect of the revolution speed, flight velocity and angle of attack on the aerodynamic characteristics of the ducted fan system is evaluated in detail. The calculation results show that the thrust of the ducted fan system shows an approximate quadratic increase with the increasing revolution speed; As the vertical velocity increases, the thrust of the ducted fan system increases first and then decreases; As the forward velocity increases, the lift and drag of the ducted fan system increase; As the angle of attack increases, the drag of the ducted fan system increases and the lift first increases and then decreases.
Optimal Design and Flow-field Simulation of a Dual Fluid Atomizer
Authors: Yu Minghao , Wang Rui , Liu Kai , Liu Kang 
Published: August 2019

Abstract
Two-dimensional turbulent flow-field properties of two types dual fluid atomizers which are currently popular in the market were numerically simulated and studied by using the commercial fluid dynamics software FLUENT. The present paper summarized their atomization characteristics respectively after studying the distribution rules of internal pressure, streamline and turbulent kinetic energy of the two kinds of dual fluid atomizers at different air flow rates. Finally, the conclusion was reached that the water absorption of the Type B atomizer is better than that of the Type A atomizer, but the secondary atomization effect of the Type B atomizer is not as good as the Type A’s.
Improved finite volume method for solving 1-D advection equation
Authors: Zhao Siyuan , Zhou Junjie , Jing Chongbo , Li Lingquan 
Published: August 2019

Abstract
In the framework of the second-order finite volume method, a new improved finite volume method (FVM) for solving one-dimensional advection equations is proposed based on its conservation form. The new method first applies the scalar conservation law to the cells in the FVM, ensuring that it is conserved in time and space, and that the flat flow (ie, the transport physical quantity) is conserved. Secondly, the time integral values of adjacent grids boundary are equalized. Finally, by establishing an equation, numerical solution values are obtained. A strong discontinuity function was used in the paper to test the new method described in this paper and compare it to the central difference method (CDM) and traditional FVM. Without the limiter, the results show that the new method described in this paper has less dissipation and better stability than CDM and traditional FVM. In addition, after adjusting the convergence condition criterion number CFL to 2, the accuracy of the numerical solution can still be guaranteed.
Simulation and Research of CFD on Internal Pressure Parallel Hollow Fiber Membrane Module
Authors: Sun Xiaohan , Li Chunqing 
Published: August 2019

Abstract
Membrane bioreactor (MBR) has been widely used in sewage treatment, effectively solving many long-standing problems such as solid-liquid separation. In this paper, the internal pressure parallel type hollow fiber membrane module was taken as the research object. Based on the CFD theory and method, the solid-liquid separation of the flow entering the membrane module was simulated by FLUENT software. Firstly, the geometric model of the internal pressure parallel membrane module was established by the computational fluid dynamics (CFD) preprocessor and structured meshing was performed. Then the volume fraction of suspended solid (SS) at the exit of the model was calculated by Eulerian multi-phase flow model and Phase Coupled SIMPLE algorithm. The calculation results were presented as images in the CFD post processor. In this paper, the simulation calculation for different concentrations of suspended solid showed that the volume fraction of suspended solid at the exit of the model was zero, which was consistent with the actual MBR system operating data. The simulation results indicated that the model established in this paper had higher accuracy. The model can simulate and predict the separation effect of solid-liquid two-phase flow in wastewater treatment, which has certain reference value for MBR engineering design and research.
Numerical simulation technology and analysis of communication in flight simulator in storm environment
Authors: Xu Lingrui , Xiong Xiong 
Published: August 2019

Abstract
Based on the particle system and aerodynamic effects, the natural phenomena in the snowstorm environment are simulated in real time. Through the hydrodynamic model, a wind model is established. The motion of the snowstorm in the hurricane environment is regarded as the comprehensive motion of the wind and the free falling body of the snow. According to the natural attributes of snow particles and the actual visual requirements of flight simulation, the mathematical calculation is simplified, and the special weather of snow is simulated. Finally, the collision between particles is briefly evaluated and analyzed.
Modal optimization approach for composite aeroelastic wing model based on a derivative-free BFGS method
Authors: Lv Binbin , Lei Pengxuan , Guo Hongtao , Kou Xiping , Yu Li 
Published: August 2019

Abstract
The optimization problem of aeroelastic wing model may lead to highly coupled nonlinear equations whose Jacobian matrix is hard to be calculated, followed by adjusting the variable domain due to design variable importance in terms of their sensitivity. To overcome the problem, an optimization function for the modal frequency is established. And a suitable line search approach is combined with the BFGS method to improve its efficiency. Some numerical results are reported to show efficiency of the proposed method. An integrated modal optimization approach based on the BFGS is developed for the model design of a composite aeroelastic wing model. The stiffness of the key beams of the wing model is designed to be the optimization variables, bending frequency and torsional frequency are designed to be the optimization objective. Then the modal of CHN-T1 is optimized, it is shown that the method proposed is suitable for the optimization of composite aeroelastic wing model with a high efficiency.
Research on the Influences of Inertial Properties on Body Freedom Flutter for an Airfoil
Authors: Lei Pengxuan , Lv Binbin , Guo Hongtao , Kou Xiping , Yu Li 
Published: August 2019

Abstract
For some flying-wing aircraft with large aspect ratio, the pitching inertia is small, which makes the longitudinal short-period modal frequency higher. Structural flexibility makes the 1st bending mode frequency lower. This makes the pitching mode of rigid body easily coupled with the elastic mode, resulting in aeroelastic instability, which is called body freedom flutter. There are many factors affecting the body freedom flutter characteristics. The rigid body inertia and structural characteristics of the fuselage and wing all have an impact on it. Taking the flutter of an airfoil as an example, the structural dynamics model of the system is established. The flutter characteristics of the airfoil were solved by analytical method. The effects of pitching inertia and fuselage mass on the flutter speed, flutter frequency and flutter mode shape were studied.
Optimization design of flue gas temperature for Low-Low Temperature Electrostatic Precipitator
Authors: Sun Ke , Yan Yu , Jiang Jiahao , Deng Lei 
Published: August 2019

Abstract
Low temperature corrosion is one of the key issues in application of low-low temperature electrostatic precipitator. The concentration of SO3 affects the acid dew point temperature of flue gas. The exhaust temperature after the air preheater should be higher than the acid dew point temperature. The residual heat of flue gas is fully utilized by the low-temperature economizer. The efficiency of low-low temperature electrostatic precipitator is improved by the comprehensive effect of the condensation of SO3 on the surface of the fine particles, the decrease of the specific resistance of the particles and the agglomeration of the fine particles.
Numerical Simulation of Longitudinal Motion of High Speed Craft in Calm Water
Authors: Liu Jianmin , Yu Xiaoping 
Published: August 2019

Abstract
In order to accurately estimate the hydrodynamic performance of high-speed crafts sailing in calm water, a numerical method based on CFD technology was established in this paper. The method included techniques such as cutting body mesh, overlapping mesh, two-phase flow, VOF model, and 6-DOF motion model. The numerical simulation of the craft’s heave and pitch coupling motion in hydrostatic water was carried out. The variation of the speed of the high speed craft with the change of the longitudinal angle and the center of gravity during the motion was analyzed. To prove feasibility and accuracy of numerical simulation method for hydrodynamic performance of longitudinal motion of high-speed crafts, the calculated results were compared with the experimental values of the ship model.
The Calculate Method of Flotation for Unbreakable Airplane
Authors: Jiang Ting , Wang Mingzhen , Zuo Zibin , Jiang Rong , He Chao 
Published: August 2019

Abstract
According to CCAR, the airplane which apply for cross ocean flight should do some airworthiness compliance on floatation after ditching. Because of the imperfect method in this area, we can not obtain the exact result which restrict the level promoted for airplane design. So an distinct and easy method is needed imminently. In this paper, we build a calculate method of attitude motion for flotation on hydrostatics, time domain and stepwise regression theories. Though decompose the yield of water into tiny part and make use of the relationship between float time and yield of water, we develop a software which is good at analyse the float time on the basic of CATIA If we study the flotation character in this way, we may save much time and simplify the complex question. In the end of this paper, we analyse the floatation for an airliner and the result shows that rhythms by calculate is good accord with that of experiment which declare the rationality of that method.
Heat dissipation analysis of electronic equipment based on CFD
Authors: Liu Xianlong , Tang Song , Feng Mei 
Published: August 2019

Abstract
In order to quantitatively analyze the heat dissipation of high-power devices, Icepak software is used for analysis. Comparing the effects of fans on heat dissipation, two models were established respectively (with fan and without fan). Combining the advantages of Icepak, the grid around the radiator is combined with structured and unstructured grid. Through the analysis, the maximum temperature decreases by 22.2°C and 36.6% when there is a fan (the flow rate is 0.003kg/s).
Numerical optimization design of vortex diode hydrodynamic cavitation reactor
Authors: Wang Jian , Chen Wei 
Published: August 2019

Abstract
Vortex diode is a novel hydrodynamic cavitation reactor, whose cavitation energy yield can be about 3∼8 times higher than the conventional ones. In this study, the numerical orthogonal experiment of the structure(Diameter of the chamber(D), Ratio of the diameter of the chamber to the diameter of axial tube(D/dc), and Ratio of the Diameter of the chamber to the height of the chamber(D/H) ) of vortex diode was carried out and the importance of the impedance ratio influence factor is: D>D/dc>D/H. The best performance was achieved when D=120mm; D/dc=5.0; D/H=5.0.Under the same conditions, the optimal value of D/H is in the range 5∼5.5 and the D/dc is in the range 4.0 ∼ 4.5.The impedance ratio was increased lightly and the flowrate was improved distinctly when we contracted the inlet and outlet of the axial and tangential tube.
Climate and soils at the Brazilian semiarid and the forest-Caatinga problem: new insights and implications for conservation
Authors: de Castro Oliveira Guilherme , Francelino Márcio Rocha , Arruda Daniel Meira , Fernandes-Filho Elpídio Inácio , Schaefer Carlos Ernesto Gonçalves Reynaud 
Published: August 2019

Abstract
This study aimed to test two hypotheses: (i) on the Brazilian semiarid territory, the climate has greater weight as a driver of vegetation than the soil and; (ii) the arboreal Caatinga is a vegetation whose environmental attributes are similar to the Dry Forest, in terms of soil and climate attributes. We analyzed attributes of the superficial horizon of 156 standardized profiles distributed throughout the Brazilian semiarid region. Bioclimatic variables were obtained from the WorldClim platform and extracted to profiles location. The main vegetation types in the region were considered: Caatinga, arboreal Caatinga, Dry Forest and Cerrado. Variable selection was performed with hierarchical correlation dendrogram and recursive feature elimination algorithm. Linear Discriminant Analysis and Random Forest (RF) algorithm were used for modeling the edaphic and climate niche and predict the vegetation with the selected variables. Climate and soil, individually, were able to separate the vegetation, but the climate was no better predictor than the soil. Therefore, we reject the first hypothesis. However, the better prediction was attained with the combined use of soil and climate attributes. The parsimonious RF model had good performance, with Kappa 0.61 ± 0.10 and 70.9% ± 7.7% accuracy. The combination of soil and climate predictors resulted in better separation of vegetation in the Brazilian semiarid region. Soil attributes are key variables in large-scale biogeographic modeling. The so-called arboreal Caatinga is distributed over a wide edaphic and climatic range, with strong similarity to the Dry Forest distribution, confirmed by the great overlap in the multivariate space, which confirms the second hypothesis. The results point towards an urgent review of the Atlantic Forest Law. The environments where the arboreal Caatinga and the Dry Forest occur are very similar, so that the former may represent a degraded phase of the Atlantic Forest, currently without the due legal protection.
Photovoltaic solar modules for autonomous heat and power supply
Authors: Panchenko V 
Published: August 2019

Abstract
The article presents solar modules of various types and designs, in the development and study of which the author took part. Along with planar photovoltaic solar modules with an extended term of nominal power, high-voltage matrix solar modules with an extended term of nominal power and electrical efficiency up to 28% are considered. Such modules are made with the help of encapsulation technology with a polysiloxane compound, which improves the performance of solar modules and increases their service life. For autonomous power supply of mobile and compact electrical devices in the field, folding and sectional solar modules are proposed, which, when parallel-sequential switching, allow to gain the necessary power. For architectural solutions, solar roofing panels are presented, which along with electrogeneration make it possible to generate heat energy, and the base can be made of recycled plastic, which has a positive effect on the environment. To reduce the number of solar cells used, a concentrating solar roofing panel has been proposed, which allows the use of thermal energy. For the cogeneration of electric energy and thermal energy, a concentrator solar photovoltaic thermal module with a paraboloid type concentrator is also proposed. Each type of solar modules is used in a stationary heat and electric power supply and mobile power generation.
Architectural and engineering solutions for high-rise residential buildings with nearly zero energy balance
Authors: Kuzhakova A , Kolgashkina V , Shilkin N 
Published: August 2019

Abstract
Optimization of consumption and distribution of resources, as well as power management efficiency improvement, are the top priority tasks for economy of most countries. Problems of world energy require innovative solutions in the area of constructing highly energy efficient buildings, based on alternative fuels. The article develops a concept of a high-rise nearly zero energy building. Due to architectural and engineering decisions, the building may autonomously produce the amount of energy which is necessary for its proper functioning.
Harmonization of a reservoir operating regime for sustainable water supply to a megalopolis
Authors: Tskhai A , Kirillov V 
Published: August 2019

Abstract
The study is aimed at sustainable water supply to a megalopolis through preserving the ecosystem of the reservoir – the source of water resources for the city. The novelty is in the approach, application of which can prevent mass zooplankton death caused by surplus water spills from the reservoir in summer and autumn. Structural-dynamic modeling of the reservoir ecosystem state is used to analyze the environmental impact of different options of water use schedule.
Problems and prospects of food security in the regions of the Russian Federation
Authors: Olgarenko G V , Ugryumova A A , Kapustina T A , Zamahovsky M P 
Published: August 2019

Abstract
The authors highlighted and substantiated the role and importance of import substitution of food for the Russian Federation in the context of the country’s food security. The study identified and classified the types of food threats to the Russian Federation which are arising from the high import intensity of the food market. The situation of territorial differentiation in the field of food supply is revealed and substantiated. The paper presents the author’s methodology, which are allowing to evaluate the contribution of each region to the import-substituting food potential of the country. The researchers used the ABC-analysis method as a result of the calculation of the import substitution’s composite index by federal districts of the Russian Federation for 2010–2012, which also revealed the positioning of individual regions in the field of import substitution and food security. The findings of regional differentiation gave a comparable result, which indicates the relevance of the study. Another significant result of the presented work was the conclusion that the climatic factor of the territory’s comfort does not guarantee that the federal districts fall into the leading group on import substitution. According to the authors of the studying, the leading factor which are ensuring the food security of the country as a whole and its individual regions is the level of socio-economic development.
A decay estimate for the eigenvalues of the Neumann-Poincaré operator using the Grunsky coefficients
Authors: Jung YoungHoon , Lim Mikyoung 
Published: August 2019

We consider the decay property of the eigenvalues of the Neumann-Poincaré operator in two dimensions. As is well known, this operator admits only a sequence of eigenvalues that accumulates to zero as its spectrum for a bounded domain having

C

1
,
α

C^{1,\alpha }

boundary with

α
∈
(
0
,
1
)

\alpha \in (0,1)

. We show that the eigenvalues

λ
k

\lambda _k

of the Neumann-Poincaré operator ordered by size satisfy that

|

λ
k

|

=
O
(

k

−
p
−
α
+
1

/

2

)

|\lambda _k| = O(k^{-p-\alpha +1/2})

for an arbitrary simply connected domain having

C

1
+
p
,
α

C^{1+p,\alpha }

boundary with

p
≥
0
,

α
∈
(
0
,
1
)

p\geq 0,~ \alpha \in (0,1)

, and

p
+
α
>

1
2

p+\alpha >\frac {1}{2}

.
Mediation by Placental DNA Methylation of the Association of Prenatal Maternal Smoking and Birth Weight
Authors: Cardenas Andres , Lutz Sharon M , Everson Todd M , Perron Patrice , Bouchard Luigi , Hivert Marie-France 
Published: August 2019

AbstractPrenatal maternal smoking is a risk factor for lower birth weight. We performed epigenome-wide association analyses of placental DNA methylation (DNAm) at 720,077 cytosine-phosphate-guanine (CpG) sites and prenatal maternal smoking among 441 mother-infant pairs (2010–2014) and evaluated whether DNAm mediates the association between smoking and birth weight using mediation analysis. Mean birth weight was 3,443 (standard deviation, 423) g, and 38 mothers (8.6%) reported smoking at a mean of 9.4 weeks of gestation. Prenatal maternal smoking was associated with a 175-g lower birth weight (95% confidence interval (CI): −305.5, −44.8) and with differential DNAm of 71 CpGs in placenta, robust to latent-factor adjustment reflecting cell types (Bonferroni-adjusted P &lt; 6.94 × 10−8). Of the 71 CpG sites, 7 mediated the association between prenatal smoking and birth weight (on MDS2, PBX1, CYP1A2, VPRBP, WBP1L, CD28, and CDK6 genes), and prenatal smoking × DNAm interactions on birth weight were observed for 5 CpG sites. The strongest mediator, cg22638236, was annotated to the PBX1 gene body involved in skeletal patterning and programming, with a mediated effect of 301-g lower birth weight (95% CI: −543, −86) among smokers but no mediated effect for nonsmokers (β = −38 g; 95% CI: −88, 9). Prenatal maternal smoking might interact with placental DNAm at specific loci, mediating the association with lower infant birth weight.
The Cultural Economies of Digital Books
Authors: Wilkens Matthew 
Published: August 2019

Abstract
An examination of the possible relations between literature and the digital. Each of three recent books, including Zara Dinnen’s The Digital Banal (2018), Andrew Piper’s Enumerations (2018), and Joel Waldfogel’s Digital Renaissance (2018), addresses a distinct aspect of the problem. Dinnen’s study considers the representational effects of social media on literary realism. Waldfogel traces the consequences of digital production and distribution on the culture industries. And Piper demonstrates the evidentiary value of quantitative analysis of literary collections. All three are persuasive within their domains, but none offers the comprehensive theory of the digital that was once the presumptive end of the study of digital books. The article suggests that the implicit renunciation of such a theory in recent work represents a new phase in the investigation of digital literature.