Aimin Gao¹, Xiaobo Cui^2,*, Guoqiang Yu¹, Jianjun Shu¹, Tianhai Zhang¹

Energy Engineering, Vol.121, No.5, pp. 1347-1361, 2024, DOI:10.32604/ee.2023.045805

Abstract Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems. The control performance of primary frequency modulation of gas turbines has a great impact on the frequency control of the power grid. However, there are some control difficulties in the primary frequency modulation control of gas turbines, such as the coupling effect of the fuel control loop and speed control loop, slow tracking speed, and so on. To relieve the abovementioned difficulties, a control strategy based on the desired dynamic equation proportional integral (DDE-PI) is proposed in this paper. Based on the parameter stability… More >

Shahid Naseem¹, Tariq Mahmood^2,3, Amjad Rehman Khan², Umer Farooq¹, Samra Nawazish⁴, Faten S. Alamri^5,*, Tanzila Saba²

CMC-Computers, Materials & Continua, Vol.79, No.1, pp. 801-817, 2024, DOI:10.32604/cmc.2024.047623

Abstract Recently, there have been several uses for digital image processing. Image fusion has become a prominent application in the domain of imaging processing. To create one final image that proves more informative and helpful compared to the original input images, image fusion merges two or more initial images of the same item. Image fusion aims to produce, enhance, and transform significant elements of the source images into combined images for the sake of human visual perception. Image fusion is commonly employed for feature extraction in smart robots, clinical imaging, audiovisual camera integration, manufacturing process monitoring, electronic circuit design, advanced device… More >

Haojie Lian¹, Jiaqi Wang¹, Leilei Chen^2,*, Shengze Li³, Ruochen Cao⁴, Qingyuan Hu⁵, Peiyun Zhao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 1143-1163, 2024, DOI:10.32604/cmes.2024.048549

Abstract This paper presents a novel framework aimed at quantifying uncertainties associated with the 3D reconstruction of smoke from 2D images. This approach reconstructs color and density fields from 2D images using Neural Radiance Field (NeRF) and improves image quality using frequency regularization. The NeRF model is obtained via joint training of multiple artificial neural networks, whereby the expectation and standard deviation of density fields and RGB values can be evaluated for each pixel. In addition, customized physics-informed neural network (PINN) with residual blocks and two-layer activation functions are utilized to input the density fields of the NeRF into Navier-Stokes equations… More >

Dawei Ruan¹, Mingwei Hu^1,2,3,4,5,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 821-844, 2024, DOI:10.32604/cmes.2024.048392

Abstract The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale, multifunctional, and complex orientations. The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units, and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts, leading to variations in the dynamic response of the foundation. The high-frequency units yield significantly diverse outcomes under different startup conditions and times, resulting in failure to meet operational requirements, influencing the normal function of the tunnel, and causing harm to the foundation structure, personnel, and property in severe cases. This article… More >

Xiao Sun¹, Jiangbo Tong¹, Yuliang Zhang^2,*, Haibing Cai³, Wen Zhou⁴, Xiaoqi Jia⁵, Litao Ou⁶

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.4, pp. 725-737, 2024, DOI:10.32604/fdmp.2023.045541

Abstract Centrifugal pumps are widely used in the metallurgy, coal, and building sectors. In order to study the hydraulic characteristics of a closed impeller centrifugal pump during its shutdown in the so-called power frequency and frequency conversion modes, experiments were carried to determine the characteristic evolution of parameters such as speed, inlet and outlet pressure, head, flow rate and shaft power. A quasi-steady-state method was also used to further investigate these transient behaviors. The results show that, compared to the power frequency input, the performance parameter curves for the frequency conversion input are less volatile and smoother. The characteristic time is… More >

Youlin Ji, Bo Yin^*, Ke Gu

CMC-Computers, Materials & Continua, Vol.78, No.3, pp. 4205-4223, 2024, DOI:10.32604/cmc.2024.049086

Abstract With its untameable and traceable properties, blockchain technology has been widely used in the field of data sharing. How to preserve individual privacy while enabling efficient data queries is one of the primary issues with secure data sharing. In this paper, we study verifiable keyword frequency (KF) queries with local differential privacy in blockchain. Both the numerical and the keyword attributes are present in data objects; the latter are sensitive and require privacy protection. However, prior studies in blockchain have the problem of trilemma in privacy protection and are unable to handle KF queries. We propose an efficient framework that… More >

Channarong Wantha^a, Kriengkrai Assawamartbunlue^a,*

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-8, 2011, DOI:10.5098/hmt.v2.4.3006

Abstract This paper presents a study of the impact of the resonance tube on performance of a thermoacoustic stack. The resonance tube is a key component of a standing-wave thermoacoustic refrigerator. The appropriated resonance tube’s length leads to an increase of performance of the stack in terms of the temperature difference. The results also indicate that the optimal operating frequency differs from the design based on the equation of a half-wavelength. The resonance tube length is elongated to compensate for some effects that occur in the resonance tube, especially when the stack is placed in the resonance tube. The relationship of… More >

Mohammad Izadifar^a,b,*, Xiongbiao Chen^a,b

Frontiers in Heat and Mass Transfer, Vol.3, No.4, pp. 1-7, 2012, DOI:10.5098/hmt.v3.4.3004

Abstract Heat can be potentially used for accelerating biodegradation of implanted tissue engineered scaffolds. Cyclic and continuous radio frequency (RF) heating was applied to implanted chitosan and alginate scaffolds at 4 applied voltages, 3 frequencies, and 2 thermally conditioning environments. A 3D finite element model was developed to simulate the RF treatment. A uniform RF heating was achieved at the scaffold top. For alginate, voltage was the only significant RF heating factor while both frequency and voltage significantly affected RF heating of chitosan. Less temperature gradient across the scaffold was achieved at a conditioning environment at <30°C. Surrounding tissue was insignificantly… More >

Vasishta Bhargava Nukala^*, Chinmaya Prasad Padhy

Sound & Vibration, Vol.58, pp. 133-150, 2024, DOI:10.32604/sv.2024.047762

Abstract A significant aerodynamic noise from wind turbines arises when the rotating blades interact with turbulent flows. Though the trailing edge of the blade is an important source of noise at high frequencies, the present work deals with the influence of turbulence distortion on leading edge noise from wind turbine blades which becomes significant in low-frequency regions. Four quasi-empirical methods are studied to verify the accuracy of turbulent inflow noise predicted at low frequencies for a 2 MW horizontal axis wind turbine. Results have shown that all methods exhibited a downward linear trend in noise spectra for a given mean wind… More >

Dan Zhao¹, Yang You², Chuanwen Luo^3,*, Ting Chen^4,*, Yang Liu⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 3063-3083, 2024, DOI:10.32604/cmes.2023.045400

Abstract In recent years, the research field of data collection under local differential privacy (LDP) has expanded its focus from elementary data types to include more complex structural data, such as set-value and graph data. However, our comprehensive review of existing literature reveals that there needs to be more studies that engage with key-value data collection. Such studies would simultaneously collect the frequencies of keys and the mean of values associated with each key. Additionally, the allocation of the privacy budget between the frequencies of keys and the means of values for each key does not yield an optimal utility tradeoff.… More >