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  • Open Access

    ARTICLE

    Mean Field-Based Dynamic Backoff Optimization for MIMO-Enabled Grant-Free NOMA in Massive IoT Networks

    Haibo Wang1, Hongwei Gao1,*, Pai Jiang1, Matthieu De Mari2, Panzer Gu3, Yinsheng Liu1

    Journal on Internet of Things, Vol.6, pp. 17-41, 2024, DOI:10.32604/jiot.2024.054791

    Abstract In the 6G Internet of Things (IoT) paradigm, unprecedented challenges will be raised to provide massive connectivity, ultra-low latency, and energy efficiency for ultra-dense IoT devices. To address these challenges, we explore the non-orthogonal multiple access (NOMA) based grant-free random access (GFRA) schemes in the cellular uplink to support massive IoT devices with high spectrum efficiency and low access latency. In particular, we focus on optimizing the backoff strategy of each device when transmitting time-sensitive data samples to a multiple-input multiple-output (MIMO)-enabled base station subject to energy constraints. To cope with the dynamic varied channel… More >

  • Open Access

    ARTICLE

    Applying the Shearlet-Based Complexity Measure for Analyzing Mass Transfer in Continuous-Flow Microchannels

    Elena Mosheva1,*, Ivan Krasnyakov2

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.8, pp. 1743-1758, 2024, DOI:10.32604/fdmp.2024.049146

    Abstract Continuous-flow microchannels are widely employed for synthesizing various materials, including nanoparticles, polymers, and metal-organic frameworks (MOFs), to name a few. Microsystem technology allows precise control over reaction parameters, resulting in purer, more uniform, and structurally stable products due to more effective mass transfer manipulation. However, continuous-flow synthesis processes may be accompanied by the emergence of spatial convective structures initiating convective flows. On the one hand, convection can accelerate reactions by intensifying mass transfer. On the other hand, it may lead to non-uniformity in the final product or defects, especially in MOF microcrystal synthesis. The ability… More > Graphic Abstract

    Applying the Shearlet-Based Complexity Measure for Analyzing Mass Transfer in Continuous-Flow Microchannels

  • Open Access

    ARTICLE

    Characteristics of Biopellets Manufactured from Various Lignocellulosic Feedstocks as Alternative Renewable Energy Sources

    Anggara Ridho Putra1, Apri Heri Iswanto1,*, Arif Nuryawan1, Saptadi Darmawan2, Elvara Windra Madyaratri2, Widya Fatriasari2, Lee Seng Hua3, Petar Antov4,*, Harisyah Manurung1, Ade Pera Amydha Sudrajat Herawati Pendi2

    Journal of Renewable Materials, Vol.12, No.6, pp. 1103-1123, 2024, DOI:10.32604/jrm.2024.051077

    Abstract The increased valorization of renewable and cost-effective lignocellulosic feedstocks represents a viable, sustainable, and eco-friendly approach toward the production of biopellets as alternative energy sources. The aim of this research work was to investigate and evaluate the feasibility of using various lignocellulosic raw materials, i.e., raru (Cotylelobium melanoxylon), mangrove (Rhizophora spp.), sengon (Paraserianthes falcataria), kemenyan toba (Styrax sumatrana), oil palm (Elaeis guineensis), manau rattan (Calamus manan), and belangke bamboo (Gigantochloa pruriens) for manufacturing biopellets with different particle sizes. The raw materials used were tested for their moisture content, specific gravity, ash, cellulose, and lignin content. In addition, thermal analyses, i.e., calorific values,… More >

  • Open Access

    ARTICLE

    Sustainable Biofuel Production from Brown and Green Macroalgae through the Pyrolysis

    Apip Amrullah1, Widya Fatriasari2, Novia Amalia Sholeha3, Edy Hartulistiyoso4, Obie Farobie4,*

    Journal of Renewable Materials, Vol.12, No.6, pp. 1087-1102, 2024, DOI:10.32604/jrm.2024.050201

    Abstract The escalating demand for energy coupled with environmental concerns necessitates exploring sustainable alternatives to fossil fuels. The study explores the viability of using large ocean-based seaweeds as a source of third-generation biomass, specifically focusing on their conversion to biofuel via the process of pyrolysis. Sargassum plagiophyllum and Ulva lactuca represent prevalent forms of macroalgae, posing significant discharge challenges for coastal regions globally. However, the exploration of their potential for bio-oil generation via pyrolysis remains limited. This study investigates the pyrolysis process of S. plagiophyllum and U. lactuca for biofuel production, aiming to provide valuable insights into their utilization and… More > Graphic Abstract

    Sustainable Biofuel Production from Brown and Green Macroalgae through the Pyrolysis

  • Open Access

    ARTICLE

    Comparative Chemical Research in Essential Oils from Six Apiaceae Species Growing in the Northern Region of Vietnam

    Nguyen Quang Hung1,2,#, Nguyen Thanh Tung3,#, Nguyen Phuong Hanh1, Chu Thi Thu Ha1, Nguyen Thi Nhung3, Nguyen Thai An3, Vu Xuan Giang3, Luong Van Hao4, Oleh Koshovyi5, Ain Raal5,*

    Phyton-International Journal of Experimental Botany, Vol.93, No.7, pp. 1677-1687, 2024, DOI:10.32604/phyton.2024.053624

    Abstract Our study aimed to compare the essential oil (EO) concentration and composition of several Apiaceae species growing in the Northern region of Vietnam. The yields of EOs from materials ranged from 0.03% (root EO of Angelica acutiloba and aerial parts EO of Heracleum bivittatum)−0.27% (leaf EO of Xyloselinum vietnamense). Gas chromatography-mass spectrometry (GC-MS) allowed the identification of 74 components in the EOs of six Apiaceae species, making up 94.4%–100.0% of the oils. In EO from Angelica acutiloba, (Z)-ligustilide accounted for an extremely large proportion (94.9%). EO of Angelica pubescens was dominated by six characteristic components including α-pinene (21.5%), β-phellandrene (18.1%), p-cymene… More >

  • Open Access

    ARTICLE

    Summer Warming Limited Bud Output Drives a Decline in Daughter Shoot Biomass through Reduced Photosynthetis of Parent Shoots in Leymus chinensis Seedlings

    Song Gao1, Ruocheng Xu2, Lin Li3, Jiao Wang2, Nian Liu2, Johannes M. H. Knops4, Junfeng Wang2,*

    Phyton-International Journal of Experimental Botany, Vol.93, No.7, pp. 1667-1675, 2024, DOI:10.32604/phyton.2024.051548

    Abstract Understanding how summer warming influences the parent and daughter shoot production in a perennial clonal grass is vital for comprehending the response of grassland productivity to global warming. Here, we conducted a simulated experiment using potted Leymus chinensis, to study the relationship between the photosynthetic activity of parent shoots and the production of daughter shoots under a whole (90 days) summer warming scenario (+3°C). The results showed that the biomass of parents and buds decreased by 25.52% and 33.45%, respectively, under warming conditions. The reduction in parent shoot biomass due to warming directly resulted from decreased… More >

  • Open Access

    ARTICLE

    Chemically Mediated Interactions between Grapevine, Aphid, Ladybird, and Ant in the Context of Insect Chemical Ecology

    Taghreed Alsufyani1,*, Noura J. Alotaibi2, Nour Houda M’sakni1, Mona A. Almalki1, Eman M. Alghamdi3

    Phyton-International Journal of Experimental Botany, Vol.93, No.7, pp. 1523-1542, 2024, DOI:10.32604/phyton.2024.050351

    Abstract This study simplifies the complex relationship among grapevine plants, aphids, ladybirds, and ants, which is essential for effective pest management and ecological balance. This study investigated the impact of aphid attacks and the presence of ants and ladybirds on the volatile compounds profile released into the chemosphere of the community consisting of the common vine Vitis vinifera, the aphid Aphis illinoisensis, the ladybird Coccinella undecimpunctata-and the ant Tapinoma magnum. This study aims to analyze the volatile compounds emitted by the grapevine and surrounding insects in response to these intricate interactions. The extraction of volatile organic compounds (VOCs) was carried… More >

  • Open Access

    ARTICLE

    Simple and High-Yield Synthesis of a Thinner Layer of Graphenic Carbon from Coconut Shells

    Retno Asih1,*, Haniffudin Nurdiansah2, Mochamad Zainuri1, Deni S. Khaerudini3,4, Angelinus T. Setiawan4, A. Y. Dias4, Pudji Untoro4,5, Ahmad Sholih1, Darminto1,*

    Journal of Renewable Materials, Vol.12, No.5, pp. 969-979, 2024, DOI:10.32604/jrm.2024.049097

    Abstract Biomass has become of recent interest as a raw material for ‘green’ graphenic carbon (GC) since it promotes an environmentally friendly approach. Here, we investigate a single pyrolysis route to synthesize GC from coconut shells which provides a simple method and can produce a high yield, thus being convenient for large-scale production. The pyrolysis involves a stepped holding process at 350°C for 1 h and at 650°C or 900°C for 3 h. The GC sample resulted at the 900°C pyrolysis has a thinner sheet, a less porous structure, a higher C/O ratio, and an enhanced More > Graphic Abstract

    Simple and High-Yield Synthesis of a Thinner Layer of Graphenic Carbon from Coconut Shells

  • Open Access

    ARTICLE

    Rock Mass Quality Rating Based on the Multi-Criteria Grey Metric Space

    Miloš Gligorić1,*, Zoran Gligorić1, Saša Jovanović2, Suzana Lutovac1, Dragan Pamučar3,4, Ivan Janković1

    CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.3, pp. 2635-2664, 2024, DOI:10.32604/cmes.2024.050898

    Abstract Assessment of rock mass quality significantly impacts the design and construction of underground and open-pit mines from the point of stability and economy. This study develops the novel Gromov-Hausdorff distance for rock quality (GHDQR) methodology for rock mass quality rating based on multi-criteria grey metric space. It usually presents the quality of surrounding rock by classes (metric spaces) with specified properties and adequate interval-grey numbers. Measuring the distance between surrounding rock sample characteristics and existing classes represents the core of this study. The Gromov-Hausdorff distance is an especially useful discriminant function, i.e., a classifier to… More >

  • Open Access

    ARTICLE

    A Novel ISSA–DELM Model for Predicting Rock Mass Permeability

    Chen Xing1, Leihua Yao1,*, Yingdong Wang2

    CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.3, pp. 2825-2848, 2024, DOI:10.32604/cmes.2024.049330

    Abstract In pumped storage projects, the permeability of rock masses is a crucial parameter in engineering design and construction. The rock mass permeability coefficient (K) is influenced by various geological parameters, and previous studies aimed to establish an accurate relationship between K and geological parameters. This study uses the improved sparrow search algorithm (ISSA) to optimize the parameter settings of the deep extreme learning machine (DELM), constructing a prediction model with flexible parameter selection and high accuracy. First, the Spearman method is applied to analyze the correlation between geological parameters. A sample database is built by comprehensively… More >

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