Alexandr Arshanitsa^*, Matiss Pals, Daniela Godina, Oskars Bikovens

Journal of Renewable Materials, Vol.12, No.11, pp. 1927-1948, 2024, DOI:10.32604/jrm.2024.056466 - 22 November 2024

Abstract The isolated hydrophilic black alder (Alnus glutinosa) bark extractives were characterized in terms of component and functional composition and converted at 150°C–170°C into liquid green polyols using solvent-free and low-toxic base-catalyzed modification with propylene carbonate (PC). FTIR spectroscopy, HP-LC, GC, GPC, and wet chemistry methods were used to characterize the starting constituents, intermediate and final products of the reaction and to monitor the different pathways of PC conversion. The reaction of extractives as well as the model compounds, including catechol, xylose, PEG 400, and benzoic acid, with PC indicated the ability of OH groups of different… More > Graphic Abstract

Weiru Wang¹, Yulong Cao^1,*, Yanxu Wang¹, Jiale You¹, Guangnan Zhang¹, Yu Xiao²

Energy Engineering, Vol.121, No.12, pp. 3801-3823, 2024, DOI:10.32604/ee.2024.055398 - 22 November 2024

Abstract To ensure frequency stability in power systems with high wind penetration, the doubly-fed induction generator (DFIG) is often used with the frequency fast response control (FFRC) to participate in frequency response. However, a certain output power suppression amount (OPSA) is generated during frequency support, resulting in the frequency modulation (FM) capability of DFIG not being fully utilised, and the system’s unbalanced power will be increased during speed recovery, resulting in a second frequency drop (SFD) in the system. Firstly, the frequency response characteristics of the power system with DFIG containing FFRC are analysed. Then, based… More >

Zhesheng Zhao¹, Shuai Li¹, Rui Han^2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.012080

Abstract This study investigates the interactions between droplets and bubbles within water-in-oil (O/W) and oil-in-water (W/O) systems, a fundamental problem of bubble dynamics in binary immiscible fluid systems. Considering the density ratio between the two fluids and the bubble-to-droplet size ratio, we have refined the classical spherical bubble pulsation equation, Rayleigh collapse time, and the natural frequency. In our experimental study, we found that the Rayleigh-Taylor (RT) instability hardly develops on the surface of the droplet when the densities of the two liquids are comparable. This phenomenon is explained using the classic theory of spherical RT More >

Shangjun Gao^1,2, Yang Yang¹, Man Chen¹, Jian Zheng¹, Luqi Qin^2,*, Xiangyu Liu², Jianying Yang¹

Energy Engineering, Vol.121, No.11, pp. 3305-3329, 2024, DOI:10.32604/ee.2024.053622 - 21 October 2024

Abstract Horizontal well drilling and multi-stage hydraulic fracturing are key technologies for the development of shale gas reservoirs. Instantaneous acquisition of hydraulic fracture parameters is crucial for evaluating fracturing effectiveness, optimizing processes, and predicting gas productivity. This paper establishes a transient flow model for shale gas wells based on the boundary element method, achieving the characterization of stimulated reservoir volume for a single stage. By integrating pressure monitoring data following the pumping shut-in period of hydraulic fracturing for well testing interpretation, a workflow for inverting fracture parameters of shale gas wells is established. This new method… More >

Fujian Zhang¹, Ziyang Wang¹, Xiang Gao¹, Zhongqiang Zhang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.011736

Abstract Spontaneous droplet transport has broad application prospects in fields such as water collection and microfluidic chips. Despite extensive research in this area, droplet self-transport is still limited by issues such as slow transport velocity, short distance, and poor integrity. Here, a novel cross-hatch textured cone (CHTC) with multistage microchannels and circular grooves is proposed to realize ultrafast directional long-distance self-transport of multi-scale droplets. The CHTC triggers two modes of fluid transport: Droplet transport by Laplace pressure difference and capillary suction pressure-induced fluid transfer in microchannels on cone surfaces. By leveraging the coupling effect of the… More >

Qiang Ma^1,2,3, Tuan Tran^2,*, Xiaodong Wang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.4, pp. 1-2, 2024, DOI:10.32604/icces.2024.011051

Abstract Controlling dynamics of impacting droplets on meshes is significantly important, which attracted a lot of attention because of its great potential applications in liquid separation, self-cleaning, and water harvesting [1-3], yet the underlying physical mechanisms are not entirely revealed. Here, the impact dynamics of a nanodroplet on mesh surfaces with different wettability are studied through molecular dynamics (MD) simulations. Due to scale effects between the nano and macroscale, the impacting nanodroplets exhibit some unique dynamic characteristics [4-7]. On a superhydrophobic mesh surface, when varying the impact conditions of nanodroplets, different outcomes can occur: (i) at… More >

Anuraag Moturi, Dharmesh R. Chejara^*

Journal of Polymer Materials, Vol.41, No.3, pp. 179-190, 2024, DOI:10.32604/jpm.2024.055887 - 30 September 2024

Abstract A chitosan and guar protein isolate blend conjugate (Ch/GPI-Glu) based membrane has been designed and studied for its possible interaction with this biopolymer mixture. The designed conjugate chitosan/guar protein isolate blended membrane was investigated for its structural features using Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. IR Spectroscopic data suggested that chitosan and guar protein isolate contributed to a specific intermolecular interaction. The designed membrane was water-insoluble and it exhibited strong polymer–protein interaction. Further, the membrane was also found to have a smooth morphology More >

Christina Khokhryakova^1,*, Konstantin Kostarev², Irina Mizeva³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.10, pp. 2205-2218, 2024, DOI:10.32604/fdmp.2024.051053 - 23 September 2024

Abstract Magnetic fluids, also known as ferrofluids, are versatile functional materials with a wide range of applications. These applications span from industrial uses such as vacuum seals, actuators, and acoustic devices to medical uses, including serving as contrast agents for magnetic resonance imaging (MRI), delivering medications to specific locations within the body, and magnetic hyperthermia for cancer treatment. The use of a non-wettable immiscible liquid substrate to support a layer of magnetic fluid opens up new possibilities for studying various fluid flows and related instabilities in multi-phase systems with both a free surface and an interface.… More > Graphic Abstract

Saif Serag^1,*, Adil Echchelh², Biagio Morrone¹

Energy Engineering, Vol.121, No.10, pp. 2719-2741, 2024, DOI:10.32604/ee.2024.054424 - 11 September 2024

Abstract Renewable energy sources are essential for mitigating the greenhouse effect and supplying energy to resource-scarce regions. However, their intermittent nature necessitates efficient storage solutions to enhance system efficiency and manage energy costs. This paper investigates renewable and clean storage systems, specifically examining the storage of electricity generated from renewable sources using hydropower plants and hydrogen, both of which are highly efficient and promising for future energy production and storage. The study utilizes extensive literature data to analyze the impact of various parameters on the cost per kWh of electricity production in hybrid renewable systems incorporating… More > Graphic Abstract

Haowei Hu^1,2,*, Qi Wang¹, Xinnuo Chen¹, Qin Li³, Mu Du⁴, Dong Niu^5,*

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 1245-1259, 2024, DOI:10.32604/fhmt.2024.054223 - 30 August 2024

Abstract To investigate the microscopic mechanism underlying the influence of surface-chemical gradient on heat and mass recovery, a molecular dynamics model including droplet condensation and transport process has been developed to examine heat and mass recovery performance. This work aimed at identify optimal conditions for enhancing heat and mass recovery through the combination of wettability gradient and nanopore transport. For comprehensive analysis, the structure in the simulation was categorized into three distinct groups: a homogeneous structure, a small wettability gradient, and a large wettability gradient. The homogeneous surface demonstrated low efficiency in heat and mass transfer, More >