Investigation of 3D particle flow in a flighted rotating drum

[EN] o validate the particle motion in flighted rotating drum (FRD), a laboratory FRD was built and operated at 15% filling degree and 10 rpm rotation speed using plastic balls as bed material. The particle tracking velocimetry (PTV) and magnetic particle tracking (MPT) techniques were applied to investigate the particle flow behavior. The 3D particle flow was modeled by Discrete Element Method (DEM) with LIGGGHTS. The height of the barycenter of all overall particles and particle instantaneous velocity were calculated from PTV and DEM data. The 3D time-averaged particle velocity distributions obtained from MPT experiment and DEM simulation were compared.Zhang, L.; Weigler, F.; Jiang, Z.; Idakiev, V.; Mörl, L.; Mellmann, J.; Tsotsas, E. (2018). Investigation of 3D particle flow in a flighted rotating drum. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 253-260. https://doi.org/10.4995/IDS2018.2018.7389OCS25326

A FEN 1-driven DNA walker-like reaction coupling with magnetic bead-based separation for specific SNP detection

Single-nucleotide polymorphism (SNP) plays a key role in the carcinogenesis of the human genome, and understanding the intrinsic relationship between individual genetic variations and carcinogenesis lies heavily in the establishment of a precise and sensitive SNP detection platform. Given this, a powerful and reliable SNP detection platform is proposed by a flap endonuclease 1 (FEN 1)-driven DNA walker-like reaction coupling with a magnetic bead (MB)-based separation. A carboxyfluorescein (FAM)-labeled downstream probe (DP) was decorated on a streptavidin magnetic bead (SMB). The target DNA, as a walker strand, was captured by hybridization with DP and an upstream probe (UP) to form a three-base overlapping structure and execute the walking function on the surface of SMB. FEN 1 was employed to specifically recognize the three-base overlapping structure and cut the 5′flap at the SNP site to report the walking event and signal amplification. Considering the fact that the fluorescence was labeled on the cleavage and uncleavage sequences of DP and the target DNA-triggered walking event was undistinguishable from the mixtures, magnetic separation came in handy for cleavage probe (CP) isolation and discrimination of the amplified signal from the background signal. In comparison with the conventional DNA walker reaction, this strategy was coupling with SMB-based separation, thus promising a powerful and reliable method for SNP detection and signal amplification

Experimental investigation and numerical simulation of the particle motion in flighted rotating drums

The particle motion in flighted rotating drum (FRD) is still a challenge due to the uncertain parameters and complicated particle movement. The number of particles in the dilute phase and the distribution of particles in the cross-section of the drum continuously change as the drum rotates. This information is essential to improve the performance of the drum and the product quality, but are not clearly understood by experimental or numerical approaches so far. In this thesis, the experimental techniques of magnetic particle tracking (MPT) and particle tracking velocimetry (PTV) are applied to track the movement of particles in FRD. Besides, the discrete element method (DEM) is used to simulate the dynamic characteristics of the granular system in the drum. In an FRD, the MPT technology is utilized to measure the particle motion. The movement of plastic balls and soybeans in a laboratory flighted rotating drum is investigated with 5 % filling degree at various rotating speeds. On the basis of tracer trajectories, translational and rotational velocity distributions of particles are evaluated. Further, the falling time of particles in the dilute phase is investigated in dependence on the discharge angle. In addition, the movement dynamics of curtains are evaluated in the equatorial region of the drum. As the measurements revealed, the particle motion in FRD is strongly influenced by the drum rotating speed and slightly affected by particle size and shape within the scope of this work. The PTV method, combining the segmentation and tracking processes, is applied to simultaneously track many particles in an FRD with a satisfactory recovery ratio. The particle motion in the cross-section of the drum is systematically analyzed based on changes in correlated particle trajectories. DEM simulations are performed in correspondence to the experimental measurements. The simulations are in agreement with PTV measurements in terms of the holdup ratio and cascading rate of a single flight, the falling time of dilute phase, the distribution of particles among the three phases, the average velocities and granular temperatures of the particle system in FRD. The effect of flights on the transverse particle motion in FRD is investigated by installing different numbers of flights on the drum. The loading and unloading profiles of the single flight and active flights, and the particle ratio of dilute phase are investigated on the basis of PTV measurements and DEM simulations. Besides, previous literature models are used to calculate the particle ratios in the flight phase and the dilute phase, respectively. A detailed comparison is represented and shows DEM simulations to agree well with PTV measurements, whereas literature models show significant deviations.Die Partikelbewegung in einer Drehtrommel mit Schaufeleinbauten (FRD) ist aufgrund der unsicheren Parameter und ihrer komplizierten Natur immer noch eine Herausforderung. Die Anzahl der Partikel in der Partikel-Gas-Phase und die Verteilung der Partikel über den Querschnitt der Trommel ändern sich kontinuierlich während der Trommeldrehung. Informationenen darüber sind entscheidend, um die Leistung der Trommel und die Produktqualität zu verbessern. Jedoch werden diese durch experimentelle oder numerische Ansätze bisher nicht ausreichend beschrieben. In dieser Arbeit werden die experimentellen Methoden der magnetischen Partikelverfolgung (MPT) und der Particle Tracking Velocimetry (PTV) angewendet, um die Bewegung von Partikeln in einer Drehtrommel mit Rechteck-Hubschaufeln zu verfolgen. Außerdem wird die Diskrete Elemente Methode (DEM) verwendet, um das dynamische Verhalten eines Schüttgutes in der Trommel zu simulieren. Die MPT-Technologie wird verwendet, um die Bewegung von Plastikkugeln und Sojabohnen in einer Labor-Drehtrommel mit Schaufeleinbauten zu analysieren. Die Partikelbewegung wird mit 5 % Füllgrad bei verschiedenen Drehzahlen untersucht. Auf der Basis von Tracer-Trajektorien werden Translations- und Rotationsgeschwindigkeitsverteilungen von Partikeln ausgewertet. Ferner wird die Fallzeit von Partikeln in der Partikel-Gas-Phase in Abhängigkeit vom Abwurfwinkel untersucht. Zusätzlich wird die Bewegungsdynamik von Partikelschleiern in der Äquatorialebene der Trommel ausgewertet. Wie die Messungen im Rahmen dieser Arbeit zeigten, wird die Partikelbewegung in FRD stark von der Rotationsgeschwindigkeit der Trommel und nur geringfügig von der Partikelgröße und -form beeinflusst. Die PTV-Methode, welche die Segmentierungs- und Verfolgungsprozesse kombiniert, wird angewendet, um gleichzeitig viele Partikel in einer FRD mit einer zufriedenstellenden Reproduktionsrate verfolgen zu können. Die Partikelbewegung im Querschnitt der Trommel wird systematisch anhand von Änderungen der korrelierten Partikelbahnen analysiert. DEM-Simulationen werden entsprechend den experimentellen Messungen durchgeführt. Die Ergebnisse der Simulationen stimmen überein mit den Ergebnissen der PTV-Messungen hinsichtlich des Füllungsgrades und der Kaskadenrate einer Einzelschaufel, der Fallzeit in der Partikel-Gas-Phase, der Verteilung der Partikel auf die drei Bewegungsphasen, der Durchschnittsgeschwindigkeiten und der granularen Temperatur des Partikelsystems in FRD. Um den Einfluss der Hubschaufelanzahl auf die transversale Partikelbewegung zu untersuchen, werden Drehtrommeln mit unterschiedlichen Anzahlen von Schaufeln präpariert. Die Lade- und Entladeprofile von Einzelschaufeln und aktiven Schaufeln sowie der Partikelanteil in der Partikel-Gas-Phase werden anhand von PTV-Messungen und DEM-Simulationen untersucht. Außerdem werden frühere Literaturmodelle verwendet, um die Partikelanteile in den Schaufeln bzw. der Partikel-Gas-Phase zu berechnen. Ein detaillierter Vergleich wird angestellt und zeigt, dass die DEM-Simulationen mit den PTVMessungen gut übereinstimmen, während Literaturmodelle signifikante Abweichungen zeigen

SIPA1 promotes angiogenesis by regulating VEGF secretion in Müller cells through STAT3 activation

Diabetic retinopathy (DR) is a prevalent complication of diabetes that can lead to vision loss. The chronic hyperglycemia associated with DR results in damage to the retinal microvasculature. Müller cells, as a kind of macroglia, play a crucial role in regulating the retinal vascular microenvironment. The objective of this study was to investigate the role of signal-induced proliferation-associated protein 1 (SIPA1) in regulating angiogenesis in Müller cells. Through proteomics, database analysis, endothelial cell function tests, and Western blot detection, we observed an up-regulation of SIPA1 expression in Müller cells upon high glucose stimulation. SIPA1 expression contributed to VEGF secretion in Müller cells and regulated the mobility of retinal vascular endothelial cells. Further investigation of the dependence of SIPA1 on VEGF secretion revealed that SIPA1 activated the phosphorylation STAT3, leading to its translocation into the nucleus. Overexpression of SIPA1 combined with the STAT3 inhibitor STATTIC demonstrated the regulation of SIPA1 in VEGF expression, dependent on STAT3 activation. These findings suggest that SIPA1 promotes the secretion of pro-angiogenic factors in Müller cells by activating the STAT3 signaling pathway, thereby highlighting SIPA1 as a potential therapeutic target for DR

Modulation Mode Recognition Method of Non-Cooperative Underwater Acoustic Communication Signal Based on Spectral Peak Feature Extraction and Random Forest

The modulation mode recognition of non-cooperative underwater acoustic (UWA) communication signal faces great challenges due to the influence of the UWA channel and the demand for efficient recognition. This work proposes a recognition method for UWA orthogonal frequency division multiplexing (OFDM), binary frequency shift keying (2FSK), four-frequency shift keying (4FSK), and eight-frequency shift keying (8FSK) by using spectral peak feature extraction combined with random forest (RF). First, a new spectral peak feature extraction method is proposed. In this method, pre-processing, waveform optimization, and feature extraction are used to ensure that the extracted feature maintains high robustness in the UWA channel. Then, we designed an RF classifier that can meet the demand for high-efficiency recognition and good performance. Finally, simulation and experimental results verified the feasibility of the recognition method

The Study on Numerical Simulation and Experiments of Four Product Hydrocyclone with Double Vortex Finders

A hydrocyclone is an instrument that can effectively separate multi-phase mixtures of particles with different densities or sizes based on centrifugal sedimentation principles. However, conventional hydrocyclones lead to two products only, resulting in an over-wide particle size range that does not meet the requirements of subsequent operations. In this article, a two-stage series, a four product hydrocyclone is proposed. The first stage hydrocyclone is designed to be a coaxial double overflow pipe: under the effect of separation, fine particles are discharged from the internal overflow pipe, while medium-size particles are discharged from external overflow pipe before entering the second stage hydrocyclone for fine sedimentation. In other words, one-stage grading leads to four products, including the first stage underflow, the first stage overflow, the second stage underflow, and the second stage overflow. The effects of structural parameters and operational parameters on flow field distribution in hydrocyclone were investigated via a study of flow field distribution in multi-product hydrocyclones using numerical simulations. The application of four product hydrocyclone in iron recovery shows that the grade and recovery of iron concentrate exceed 65.08% and 86.14%, respectively. This study provides references for understanding the flow field distribution in hydrocyclones and development of multi-product grading instrument in terms of both theory and industrial applications

Modulation Mode Recognition Method of Non-Cooperative Underwater Acoustic Communication Signal Based on Spectral Peak Feature Extraction and Random Forest

The modulation mode recognition of non-cooperative underwater acoustic (UWA) communication signal faces great challenges due to the influence of the UWA channel and the demand for efficient recognition. This work proposes a recognition method for UWA orthogonal frequency division multiplexing (OFDM), binary frequency shift keying (2FSK), four-frequency shift keying (4FSK), and eight-frequency shift keying (8FSK) by using spectral peak feature extraction combined with random forest (RF). First, a new spectral peak feature extraction method is proposed. In this method, pre-processing, waveform optimization, and feature extraction are used to ensure that the extracted feature maintains high robustness in the UWA channel. Then, we designed an RF classifier that can meet the demand for high-efficiency recognition and good performance. Finally, simulation and experimental results verified the feasibility of the recognition method