Experiments were performed to evaluate temporal changes in the fractal dimension of aggregates formed during flocculation of an initially monodisperse suspension of latex microspheres. Particle size distributions and aggregate geometrical information at different mixing times were obtained using a non-intrusive optical sampling and digital image analysis technique, under variable conditions of mixing speed, coagulant (alum) dose and particle concentration. Pixel resolution required to determine aggregate size and geometric measures including the fractal dimension is discussed and a quantitative measure of accuracy is developed. The two-dimensional fractal dimension was found to range from 1.94 to 1.48, corresponding to aggregates that are either relatively compact or loosely structured, respectively. Changes in fractal dimension are explained using a conceptual model, which describes changes in fractal dimension associated with aggregate growth and changes in aggregate structure. For aggregation of an initially monodisperse suspension, the fractal dimension was found to decrease over time in the initial stages of floc formation.
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http://dx.doi.org/10.1016/s0043-1354(02)00379-2 | DOI Listing |
Polymers (Basel)
January 2025
School of Civil Engineering and Transportation, Northeast Forestry University, Harbin 150040, China.
This article systematically investigated the improvement effect of polypropylene fiber (PPF) on the mechanical and freeze-thaw properties of alkali-activated fly ash slag concrete (AAFSC) with high fly ash content and cured at room temperature. Fly ash and slag were used as precursors, with fly ash accounting for 80% of the total mass. A mixed solution of sodium hydroxide and sodium silicate was used as alkali activator, and short-cut PPF was added to improve the performance of AAFSC.
View Article and Find Full Text PDFJ Clin Med
January 2025
Surgical Services, Miami Veterans Healthcare System, Miami, FL 33125, USA.
: This study aimed to evaluate the location of retinal fractal dimension (FD) abnormalities in individuals with diabetes mellitus (DM) and hypertension (HTN) without retinopathy. The annular zone of 6 mm × 6 mm OCTA images centered on the fovea was partitioned into thin annuli and analyzed using fractal analysis to measure FDs. The cohort ( = 114) had an average age of 55.
View Article and Find Full Text PDFBiomedicines
January 2025
Biomedical Engineering Division, James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
The objective was to test the generalisability of electroencephalography (EEG) markers of future pain using two independent datasets. Datasets, A [N = 20] and B [N = 35], were collected from participants with subacute spinal cord injury who did not have neuropathic pain at the time of recording. In both datasets, some participants developed pain within six months, (PDP) will others did not (PNP).
View Article and Find Full Text PDFEntropy (Basel)
January 2025
School of Tourism and Planning, Pingdingshan University, Pingdingshan 467000, China.
The formation and development of cities are inseparable from a certain scale of water resources. The information contained in the morphological structures of cities and water systems is often overlooked. Exploring the spatiotemporal evolution of water system structures (WSS) and urban system structures (USS) can reveal the "urban-water" relationship from a new perspective.
View Article and Find Full Text PDFOphthalmol Sci
November 2024
Department of Ophthalmology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Objective: To explore the association between retinal microvascular parameters and glaucoma.
Design: Prospective study.
Subjects: The UK Biobank subjects with fundus images and without a history of glaucoma.
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