Jiyuan Zhang¹, Linbo Wang¹, Chengqiang Zhang¹, Shuzhan Bai^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 615-621, 2020, DOI:10.32604/fdmp.2020.09654 - 25 May 2020

Abstract The influences of steam and sulfide on the efficiency of NOx reduction using ammonia (NH₃) over the nanometer-class V-W/Ti catalyst in conditions of high temperature is experimentally investigated using a steady-flow reactor. The results showed that selective catalytic reduction (SCR) is inhibited by H₂O at low temperature, but higher NO conversion efficiency is achieved at high temperature since the reaction of NH3 oxidized by O₂ to NOx is inhibited by H₂O. The activity of SCR is promoted by SO₂ in the temperature range of 200~500° C, the NO conversion efficiency was improved to 98% from 94% by adding More >

Nan Wu^1,#, Kuan Lu^1,2,#,*, Yulin Jin^2,3,*, Haopeng Zhang¹, Yushu Chen²

Sound & Vibration, Vol.54, No.2, pp. 113-125, 2020, DOI:10.32604/sv.2020.09783 - 09 May 2020

Abstract Two different order reduction methods of the deterministic and stochastic systems are discussed in this paper. First, the transient proper orthogonal decomposition (T-POD) method is introduced based on the high-dimensional nonlinear dynamic system. The optimal order reduction conditions of the T-POD method are provided by analyzing the rotor-bearing system with pedestal looseness fault at both ends. The efficiency of the T-POD method is verified via comparing with the results of the original system. Second, the polynomial dimensional decomposition (PDD) method is applied to the 2 DOFs spring system considering the uncertain stiffness to study the More >

Ling Li^1,*, Xuyu Yan¹, Lei Mei², Shuijin Zhu²

Phyton-International Journal of Experimental Botany, Vol.89, No.2, pp. 315-327, 2020, DOI:10.32604/phyton.2020.09108 - 22 April 2020

Abstract The risk of cotton production on arable land contaminated with heavy metals has increased in recent years. Cotton shows stronger and more extensive resistance to heavy metals, such as cadmium (Cd) than that of other major crops. Here, a potted plant experiment was performed to study Cd-induced alterations in the cottonseed kernel gossypol content and pigment gland structure at maturity in two transgenic cotton cultivars (ZD-90 and SGK3) and an upland cotton standard genotype (TM-1). The results showed that Cd accumulation in cottonseed kernels increased with increasing Cd levels in the soil. The seed kernel… More >

Ali Safari Variani¹, Ali Dastamoz¹, Sajad Zare², Ahmad Nikpey¹, Saeid Ahmadi^1,*

Sound & Vibration, Vol.54, No.1, pp. 43-55, 2020, DOI:10.32604/sv.2020.08636 - 01 March 2020

Abstract This work investigated multiple jet nozzles with various geometrical shape, number of exits, and material on reducing noise radiated from jet flows. Nozzles are categorized in two groups with few and many exit numbers, each with various exit shapes, slot and circular, and geometry. Firstly, nozzles are designed and then fabricated by a 3D printer, Form Labs, Form2USA, with polymeric resin. Also, the nozzle with the most noise reduction made of stainless steel. Noise and air thrust were measured at three air pressure gauges, 3, 5, 7 BAR and directions from nozzle apex, 30°, 90°,… More >

Jiali Liu¹, Mengge Yu^{2, *}, Dawei Chen¹, Zhigang Yang³

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 21-30, 2020, DOI:10.32604/fdmp.2020.07658 - 01 February 2020

Abstract In order to investigate how the aerodynamic drag and noise produced by the roof air conditioner of a high-speed train can be reduced, the related unsteady flow in the near-field was computed using the method of large eddy simulation. In this way, the aerodynamic source for noise generation has initially been determined. Then, the far-field aerodynamic noise has been computed in the framework of the Lighthill’s acoustics analogy theory. The propulsion height and flow-guide angle of the roof air conditioner were set as the design variables. According to the computational results, a lower propulsion height More >

Siyang Piao¹, Huajiang Ouyang^{1, 2}, Yahui Zhang^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.2, pp. 571-591, 2020, DOI:10.32604/cmes.2020.08789 - 01 February 2020

Abstract A beam approximation method for dynamic analysis of launch vehicles modelled as stiffened cylindrical shells is proposed. Firstly, an initial beam model of the stiffened cylindrical shell is established based on the cross-sectional area equivalence principle that represents the shell skin and its longitudinal ribs as a beam with annular cross-section, and the circumferential ribs as lumped masses at the nodes of the beam elements. Then, a fine finite element model (FE model) of the stiffened cylindrical shell is constructed and a modal analysis is carried out. Finally, the initial beam model is improved through… More >

Fengrui Liu^{1, 2, 3}, Wanting Yao^{1, 2}, Xinhong Shi^{4, *}, Libin Zhao^{1, 2}, Jianyu Zhang^{5, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 977-999, 2020, DOI:10.32604/cmc.2020.07184

Abstract To minimize the mass and increase the bearing failure load of composite doublelap bolted joints, a three-step optimization strategy including feasible region reduction, optimization model decoupling and optimization was presented. In feasible region reduction, the dimensions of the feasible design region were reduced by selecting dominant design variables from numerous multilevel parameters by sensitivity analyses, and the feasible regions of variables were reduced by influence mechanism analyses. In model decoupling, the optimization model with a large number of variables was divided into various sub-models with fewer variables by variance analysis. In the third step, the More >

Jahede Tekeykhah¹, Seyed Mohsen Hosseini^2,*, Gholamali Jalali³, Jalil Alavi⁴, Abbas Esmaili Sari⁵

Sound & Vibration, Vol.53, No.6, pp. 263-276, 2019, DOI:10.32604/sv.2019.07157

Abstract Sound pollution is one of the most important urban problems which endangers mental and physical health of the residents. This study was aimed to assess the influence of different tree species, including Fraxinus rotundifolia, Robinia pseudoacacia, Platanus orientalis, Platycladus orientalis, and Pinus eldarica, in reducing noise pollution in the Abidar Forest Park. A further objective was to identify the contaminated areas of Sanandaj city and to propose suitable noise absorbent tree species in consistent conditions. For each tree stands the noise measurements were performed during intervals at frequencies of 250, 500 and 1000 Hz, besides an open area with the… More >

Yongyun Zhu¹, Tao Zhang^1,*, Mohan Li², Di Wang¹, Shaoen Wu³

CMC-Computers, Materials & Continua, Vol.61, No.3, pp. 1305-1321, 2019, DOI:10.32604/cmc.2019.06406

Abstract The observation vectors in traditional coarse alignment contain random noise caused by the errors of inertial instruments, which will slow down the convergence rate. To solve the above problem, a real-time noise reduction method, sliding fixed-interval least squares (SFI-LS), is devised to depress the noise in the observation vectors. In this paper, the least square method, improved by a sliding fixed-interval approach, is applied for the real-time noise reduction. In order to achieve a better-performed coarse alignment, the proposed method is utilized to de-noise the random noise in observation vectors. First, the principles of proposed More >

Haitong Zhao¹, Yi Li¹, Shouhua Luo^1,*

Molecular & Cellular Biomechanics, Vol.16, No.4, pp. 265-273, 2019, DOI:10.32604/mcb.2019.07381

Abstract The ring artifacts introduced by the defective pixels with non-linear responses in the high-resolution detector, have a great impact on subsequent processing and quantitative analysis of the reconstructed images. In this paper, a multistep method is proposed to suppress the ring artifacts of micro CT images, which firstly locates the positions of the defective pixels in the sinogram, and then corrects the corresponding value in the projections. Since the defective pixels always appear as vertical stripes in the sinogram, a horizontal curve is derived by summing the pixel values along vertical direction, thus the abrupt… More >