Filament Diameter Research Articles

Dissecting spacer induced membrane deformation and fluid hydraulic behavior in reverse osmosis

Feed spacer is a key component of the spiral wound membrane module. However, the membrane deformation induced by the feed spacer under high pressure presents a significant challenge to long-term operation of reverse osmosis (RO) membrane. This deformation alters the fluid hydraulic behavior within the feed channel and its underlying mechanism remains elusive. In this study, the computational fluid dynamics (CFD) simulation was conducted to illustrate the impact of the feed spacer geometry on membrane deformation under high pressure and the resultant changes in hydraulic performances. The simulated results revealed that an increase in the mesh angle and a reduction in the filament diameter and length, led to a higher degree of membrane deformation. In addition, larger mesh angles and filament diameters, and shorter the filament lengths could significantly enhance the performance of the spiral wound membrane (SWM) module. This study provides an insight for the design of feed spacer to optimize the performance of reverse osmosis membrane module.

Experimental Investigation of Tensile, Shear, and Compression Behavior of Additional Plate Damping Structures with Entangled Metallic Wire Material

To fulfill the vibration damping requirements of plate structures under complex conditions, additional damping structures with entangled metallic wire material (EMWM) are proposed based on the excellent physical properties of EMWM. A batch of specimens with different filament diameters, densities, and thicknesses are prepared. The stiffness and loss factors are taken as the evaluation indexes, and orthogonal tests are conducted to obtain the tensile, shear, and compression properties. The results show that the optimal parameter combinations can be obtained through orthogonal tests. For the specimens with optimal parameter combinations, the mechanical tests under different loading rates and loading displacements are carried out. With the increase in loading rate, the tensile and shear forces appear to display fracture failure in advance, and the compression performance is stable without significant changes. The change rule under each mechanical test is explored using the stiffness and loss factor evaluation index. It provides a reference for the analysis of the preparation parameters of subsequent additional damping structures with EMWM.

Medical- and Non-Medical-Grade Polycaprolactone Mesh Printing for Prolapse Repair: Establishment of Melt Electrowriting Prototype Parameters

Pelvic organ prolapse (POP) occurs due to inadequate support of female pelvic organs and is often treated with synthetic implants. However, complications like infections, mesh shrinkage, and tissue erosion can arise due to biomechanical incompatibilities with native tissue. This study aimed to optimize the melt electrowriting process using medical-grade biodegradable Poly(ε-caprolactone) (PCL) with a pellet extruder to print meshes that mimic the mechanical properties of vaginal tissue. Square and diagonal mesh designs with filament diameters of 80 µm, 160 µm, and 240 µm were produced and evaluated through mechanical testing, comparing them to a commercial mesh and sheep vaginal tissue. The results showed that when comparing medical-grade with non-medical-grade square meshes, there was a 54% difference in the Secant modulus, with the non-medical-grade meshes falling short of matching the properties of vaginal tissue. The square-shaped medical-grade PCL mesh closely approximated vaginal tissue, showing only a 13.7% higher Secant modulus and a maximum stress of 0.29 MPa, indicating strong performance. Although the diagonal-shaped mesh exhibited a 14% stress difference, its larger Secant modulus discrepancy of 45% rendered it less suitable. In contrast, the commercial mesh was significantly stiffer, measuring 77.5% higher than vaginal tissue. The diagonal-shaped mesh may better match the stress–strain characteristics of vaginal tissue, but the square-shaped mesh offers stronger support due to its higher stress–strain curve. Overall, meshes printed with medical-grade PCL show superior performance compared to non-medical-grade meshes, suggesting that they are a promising avenue for future advancements in the field of POP repair.

Comparative study of blending techniques in polylactic acid/cellulose nanofibrils green composites for benchtop 3D printing filaments

AbstractAdditive manufacturing for polylactic acid (PLA) reinforced with cellulose nanofibrils (CNF) could unlock fabrication of specialized and user‐specific biomedical devices. However, the process of combining PLA and CNF is challenging and proves complicated with possible irreversible CNF agglomeration and organic solvents leftover, particularly when involving solvent‐casting technique. Direct melt‐blending can mitigate these issues, but there are few reports of a single‐step melting and extrusion process to produce ready‐to‐use 3D printing filaments. This study compares the distribution of CNF fillers within the PLA matrix in PLA/CNF composites made by direct melt‐blending into filaments using a benchtop filament maker, and by solvent‐casting followed by extrusion into filaments. The filaments were 3D‐printed via fused deposition modeling (FDM), followed by tensile testing, morphology, and other characterizations. Uneven filament diameters were observed for the composite filaments prepared via solvent‐casting because of severe agglomeration, resulted in poor printability and tensile properties of filaments and 3D‐printed samples. Direct melt‐blended filament diameters were consistent, resulted in only slight decrease of tensile properties compared to pure PLA, contributing to the highest maximum tensile strength of 3D‐printed sample of 51.47 ± 1.73 MPa at 5% CNF loading. Morphology revealed good integration of CNF into PLA matrix starting at 3% CNF loading. Direct melt‐blending was comparable to the conventional methods, which enables simpler PLA/CNF composite preparation especially for 3D printing.Highlights Better dispersibility achieved by direct melt‐blending than by solvent‐casting. PLA/CNF filaments produced via solvent‐casting suffered severe agglomeration. Direct melt‐blended PLA/CNF5% yielded the highest maximum tensile strength. Morphology reveals good CNF‐PLA integration starting at 3% of CNF loading. Worsened agglomeration causing increased number of voids observed at 10% CNF.

Spontaneous imbibition in thin anisotropic fibrous media: Experiments and numerical modeling

In this study, we investigate the temporal and spatial evolution of wetting saturation during spontaneous imbibition in anisotropic fibrous porous media using both experimental and numerical methods. We present a novel experimental approach to systematically study spontaneous imbibition in these media, allowing for a comprehensive assessment of how microstructure influences wicking performance. The experimental method, which exhibits high reproducibility, was used to validate the numerical model. The numerical model was parameterized using only the porosity and filament diameter of the porous media in conjunction with the material properties of the imbibing fluid. The essential capillary saturation curve for the numerical model was derived using the pore morphology method. The numerical results effectively replicated the experimental results. Our experimental and numerical observations revealed a diffusive wetting front within the porous media, which progressively expanded and decelerated during the imbibition process. The results highlight the significant influence of filament size on the wetting saturation dynamics and the height of the wetting front during spontaneous imbibition.

Topological polymeric glucosyl nanoaggregates in scaffold enable high-density piscine muscle tissue

Upon the pressure of conventional land agriculture and marine environment facing the future of human beings, the emerging of alternative proteins represented by cultured meat is expected with a breakthrough of efficient, safe and sustainable production. However, the cell proliferation efficiency and final myofiber density in current animal-derived scaffolds are still limited. Here, we incorporated five plant-derived edible polymeric glucosyl nanoparticles (GNPs) into gelatin/alginate hydrogels to spontaneously form nanoaggregates where nanotopographies were observed inside. The nanoscale topological morphology significantly enhances the adhesion and proliferation efficiencies of piscine satellite cells (PSCs) in the tailored extracellular matrix of as-prepared scaffold. Physically, the presence of GNP-induced nanoaggregate increases the interaction between ITG-A1 (membrane protein of PSCs) and hydrogel microenvironment, which activates the focal adhesion-integrin-cytoskeleton mechanotransduction signaling to promote cell proliferation. With a controlled diameter of hydrogel filament, these inner topological GNP nanoaggregates can also improve the density, alignment and differentiation efficiency of PSCs. When cultured in vitro for 15 days, the cell density, size and orientation of muscle fibers in the GNP-stimulated cultured fish fillet are very similar to the total cell mass in native fish muscle tissue.

Fabrication of a 3D Printer Filamnet Extruder

3D printing, an additive manufacturing process, transforms digital designs into physical objects by layering material. This mechanization adds consecutive layers to build up the complete entity, resulting in a 3D object. It develops objects progressively to formulate the preferred look. Filaments are the main component in a die cast model (FDM) 3D printer, these are thermoplastic substances that are injected through a hot die to form the object. These filaments are available in different types such as PLA, ABS, PETG, HDPE each of which has specific characteristics that offer different applications and material options in 3D printing. This paper depicts about fabricating and developing a design of a 3D filament extruder that can produce 1.75 mm diameter filaments from recycled HDPE material. The extruder consists of a motor, a speed controller, a cylinder, a hopper, band heaters, a thermocouple, a temperature controller, a fan, a nozzle and a winder. This system works in the correct temperature range of 350-370 degrees Celsius for melting thermoplastic materials (recycled HDPE). Extruder function is to feed the material from the nozzle into the hot cylinder. A motor screw pushes the metal into the nozzle, where it becomes the filament. This filament is then injected onto a substrate for later use in 3D printing. The temperature is determined using thermocouples and a temperature controller, which ensures optimal extraction conditions. A fan is designed to quickly cool the removed filament. The objective of this research is to create an economical as well as efficient filament to produce high quality filaments. Extruder performance is evaluated based on filament diameter consistency, material penetration and energy efficiency.

3D Bioprinting of Engineered Living Materials with Extracellular Electron Transfer Capability for Water Purification.

Attention is widely drawn to the extracellular electron transfer (EET) process of electroactive bacteria (EAB) for water purification, but its efficacy is often hindered in complex environmental matrices. In this study, the engineered living materials with EET capability (e-ELMs) were for the first time created with customized geometric configurations for pollutant removal using three-dimensional (3D) bioprinting platform. By combining EAB and tailored viscoelastic matrix, a biocompatible and tunable electroactive bioink for 3D bioprinting was initially developed with tuned rheological properties, enabling meticulous manipulation of microbial spatial arrangement and density. e-ELMs with different spatial microstructures were then designed and constructed by adjusting the filament diameter and orientation during the 3D printing process. Simulations of diffusion and fluid dynamics collectively showcase internal mass transfer rates and EET efficiency of e-ELMs with different spatial microstructures, contributing to the outstanding decontamination performances. Our research propels 3D bioprinting technology into the environmental realm, enabling the creation of intricately designed e-ELMs and providing promising routes to address the emerging water pollution concerns.

A preliminary study of the mechanical properties of 3D-printed personalized mesh titanium alloy prostheses and repair of hemi-mandibular defect in dogs.

This study is a preliminary investigation exploring the mechanical properties of three-dimensional (3D)-printed personalized mesh titanium alloy prostheses and the feasibility of repairing hemi-mandibular defects. The ANSYS 14.0 software and selective laser melting (SLM) were used to produce personalized mesh titanium alloy scaffolds. Scaffolds printed using different parameters underwent fatigue property tests and scanning electron microscopy (SEM) of the fracture points. Models of hemi-mandibular defects (encompassing the temporomandibular joint) were created using beagle dogs. Freeze-dried allogeneic mandibles or 3D-printed personalized mesh titanium alloy prostheses were used for repair. Gross observation, computed tomography (CT), SEM, and histological examinations were used to compare the two repair methods. The prostheses with filament diameters of 0.5 and 0.7 mm could withstand 14,000 times and >600,000 cycles of alternating stresses, respectively. The truss-structure scaffold with a large aperture and large aperture ratio could withstand roughly 250,000 cycles of alternating forces. The allogeneic mandible graft required intraoperative shaping, while the 3D-printed mesh titanium alloy prostheses were personalized and did not require intraoperative shaping. The articular disc on the non-operated sides experienced degenerative changes. No liver and kidney toxicity was observed in the two groups of animals. The 3D-printed mesh titanium alloy prostheses could effectively restore the shape of the mandibular defect region and reconstruct the temporomandibular joint.

Controllable fabrication of shape memory epoxy resin filament by polymerization-melting-mixing-drawing process and performance regulation

ABSTRACT This work controlled the polymerization reaction, melting, and mixing processing of a mixture including epoxy resin and polyethylene glycol (PEG) by a pulverizer, to effectively develop high-performance shape memory epoxy/PEG (EPP) filaments. The process parameters of polymerization-melting-mixing-drawing were determined through the extrusion force investigation. The results showed that EPP mixtures could be developed into filaments through polymerization-melting-mixing-drawing process, reducing the spinning temperature and filament diameter from 300°C and 31 mm to 235°C and 13 mm, respectively. The Fourier transform infrared spectra confirmed the complete polymerization of epoxy resin and the stable existence of PEG. EPP filaments developed through the polymerization-melting-mixing-drawing process have exhibited controllable dynamic thermal mechanical properties and Tg, excellent shape recovery effects, and adjustable stimulus temperature. This work developed shape memory EPP filaments through a polymerization-melting-mixing-drawing process, with controllable spinnability and adjustable stimulus temperature, providing a reference for high-performance filament fabrication and process optimization.

Mechanical Characteristics of Multi-Level 3D-Printed Silicone Foams.

Three-dimensional-printed silicone rubber foams, with their designable and highly ordered pore structures, have shown exceptional potential for engineering applications, particularly in areas requiring energy absorption and cushioning. However, optimizing the mechanical properties of these foams through structural design remains a significant challenge. This study addresses this challenge by formulating the research question: How do different 3D-printed topologies and printing parameters affect the mechanical properties of silicone rubber foams, and how can we design a novel topological structure? To answer this, we explored the mechanical behavior of two common structures-simple cubic (SC) and face-centered tetragonal (FCT)-by varying printing parameters such as filament spacing, filament diameter, and layer height. Furthermore, we proposed a novel two-level 3D-printed structure, combining SC and FCT configurations to enhance performance. The results demonstrated that the two-level SC-SC structure exhibited a specific energy absorption of 8.2 to 21.0 times greater than the SC structure and 2.3 to 7.2 times greater than the FCT structure. In conclusion, this study provides new insights into the design of 3D-printed silicone rubber foams, offering a promising approach to developing advanced cushioning materials with superior energy absorption capabilities.

Characterisation and manufacturing methods of material extrusion 3D printing composite filaments based on polylactide and nanohydroxyapatite

As the pace of scientific research and technological advancement accelerates, there is an increasing demand for rapid on-site prototyping with specific materials. Additive manufacturing through material extrusion 3D printing has emerged as an economically viable solution to this need. The production of custom filaments for this process frequently depends on low-volume filament manufacturing lines. A significant challenge in such production processes is maintaining the quality of the filament throughout its entire length, as this has a considerable impact on the quality of the final printed object. To ensure consistent quality, it is essential to monitor and manage a range of essential properties, including diameter consistency, material homogeneity and compound ratio. This study presents the implementation of a real-time filament quality monitor (R-FQM), which provides detailed insight into the longitudinal characteristics of the filament during the manufacturing process and its crystallinity analysis. In conjunction with a new proof-of-concept drawing process for reducing filament diameter by multi stage drawing die solid-state extrusion, this approach addresses the challenge of maintaining filaments quality. Several PLA-based filaments were produced for research purposes: pure PLA and composites containing 5 and 10 wt% nanohydroxyapatite. Produced composite filaments had significantly greater diameter variation compared to pure PLA (largest for 5 % filler ± 0.29 mm). The diameter of the resulting filaments was reduced in the range of 2.5–1.4 mm using the SSE approach. In addition to the R-FQM method, the filaments were characterised by structural, thermal and mechanical property analysis. The analyses showed that the 10 % hydroxyapatite content in the filament subjected to the SSE process can lead to significant weakening of the material. However, all the filaments were suitable for 3D printing for biomedical applications. The research carried out demonstrated the complementarity of the R-FQM method with classical methods, confirming the effectiveness of the approach described.

Mechanical strategies supporting growth and size diversity in Filamentous Fungi.

The stereotypical tip growth of filamentous fungi supports their lifestyles and functions. It relies on the polarized remodeling and expansion of a protective elastic cell wall (CW) driven by large cytoplasmic turgor pressure. Remarkably, hyphal filament diameters and cell elongation rates can vary extensively among different fungi. To date, however, how fungal cell mechanics may be adapted to support these morphological diversities while ensuring surface integrity remains unknown. Here, we combined super-resolution imaging and deflation assays to measure local CW thickness, elasticity and turgor in a set of fungal species spread on the evolutionary tree that spans a large range in cell size and growth speeds. While CW elasticity exhibited dispersed values, presumably reflecting differences in CW composition, both thickness and turgor scaled in dose-dependence with cell diameter and growth speeds. Notably, larger cells exhibited thinner lateral CWs, and faster cells thinner apical CWs. Counterintuitively, turgor pressure was also inversely scaled with cell diameter and tip growth speed, challenging the idea that turgor is the primary factor dictating tip elongation rates. We propose that fast-growing cells with rapid CW turnover have evolved strategies based on a less turgid cytoplasm and thin walls to safeguard surface integrity and survival.

Simultaneous production of highly pure hydrogen and carbon nanofibers through COx-free methane dissociation over Ni-based catalysts: Investigation of the promotional effects of transitional metal (Mn, Zr, and Zn)

Hydrogen and carbon nanotubes are two novel and engaging research topics in clean fuel and material science. Methane decomposition is the most advantageous itinerary for the concurrent production of COx-free hydrogen and carbon filaments. The 50Ni/Al2O3 catalyst was successfully fabricated using a simple one-pot hydrothermal method, and the influence of transition metals (Zr, Mn, and Zn) was investigated as the promoter. The homogeneous accumulation of the nanoparticles with a high specific surface area of 101–147 m2.g−1 was revealed to be the consequence of the mesoporous structure's presence. The reactor tests' findings demonstrated that synthesized bimetallic catalysts are more stable and active than monometallic catalysts. Besides, the Zn-modified catalyst was shown to have the highest performance and durability. The maximal methane conversions of 65.7, 77.2, 69.6, and 51.7 % were achieved over the 50Ni-xZn/Al2O3 (defined as 50Ni-xZn/Al2O3; x = 2.5, 5, 7.5, and 10 wt%) at 650 °C and GHSV = 24,000 mL.(h.gcat)−1, respectively. A deeper look at the microstructure and textural characteristics of the aged catalysts makes it clear that the zinc promoter introduced to the 50Ni/Al2O3 sample, by increasing the growth rate of carbon fiber/nanotube, changes the structure of the formed carbons from spherical shape to very homogeneous diameter filaments and lead to the production of ordered carbon filaments with better crystallinity.

Design of an Extrudate Filament Machine for Recycling Waste Polyethylene Terephthalate Plastics into 3D Printing Filament

This research paper presents the design of an extrudate filament machine tailored for recycling waste Polyethylene Terephthalate (PET) plastics into filament suitable for 3D printing. The exponential growth of plastic waste, particularly PET, poses significant environmental challenges. Recycling PET into usable filament for 3D printers not only addresses environmental concerns but also promotes sustainable manufacturing practices. The design process encompasses a thorough analysis of requirements, considering factors such as input material variability, filament diameter consistency, and production throughput. Through conceptual and detailed design phases, the machine is optimized to effectively shred, melt, extrude, cool, and wind the recycled PET material into uniform filament spools. Material selection is carefully curated to ensure durability, thermal stability, and compatibility with PET recycling processes. The machine integrates various components such as shredders, extruders, cooling systems, and filament winding mechanisms to efficiently process waste PET plastics. Furthermore, the paper explores the economic feasibility and environmental benefits of implementing such a system for local plastic recycling initiatives.

Evaluation of operational process parameters of polylactic acid filament extruder by quality and dynamic‐mechanical analysis measurements: A comparative study and classification

AbstractIn this study, the operational conditions of a low‐cost in‐house‐built single screw filament extruder including operational parameters of extruder temperature (170–190°C) and screw speed (20–40 rpm) were evaluated in terms of the quality and dynamic‐mechanical properties of extruded PLA filaments. The designed experimental parameters were used to investigate the impact of operational parameters on filament diameter by Taguchi model where the predicted responses were evaluated. Results showed superior performance with R2 value of 0.9898. The measured filament diameters validated the predicted responses, and the error percentage was in the range of 0%–2.1%. Furthermore, in order to classify and distinguish filaments, we adept the artificial neural network (ANN) model classifier, and the measured dynamic mechanical analysis (DMA) values at certain temperatures were taken into consideration where the classes they belonged to be determined. Results reveal successful classification accuracy of filaments in the range of 94.82%–99.98% depends on different cases of classification process.

A short banana fiber—PLA filament for 3D printing: Development and characterization

AbstractThis study aims to develop a 3D printable composite filament using short banana fiber and polylactic acid (PLA). The filament was acquired through a single screw extruder, employing various blending techniques. Various fiber loadings were examined, impacting PLA's mechanical, thermal, and printability properties. The results revealed altered mechanical characteristics, with reduced tensile and flexural properties compared with pure PLA. However, these values are at an acceptable level for non‐structural applications. Compared with previous works, the filament developed in the present work is found out to be second strongest among the cellulose fiber‐reinforced PLA filaments. 3D printing with the composite filament encountered no significant issues. A modified mixing method improved mechanical characteristics, although 3D‐printed samples showed deteriorated mechanical characteristics due to poor interfacial bonding. This research introduces an environmentally viable strategy for advancing 3D printing technology by integrating banana fibers into PLA filament. The proposed strategy can be effectively utilized in making cellulose/PLA filaments for 3D printing applications. This innovative approach preserves PLA's natural biodegradability while carefully managing the integration of banana fibers and their potential effects on mechanical properties.Highlights Fiber loading influences mechanical, with minimal impact on thermal properties. Solution casting improved fiber/matrix bonding and filler homogeneity. Plasticizing effect reduces the tensile strength. Modified mixing resulted in even filament diameter and improved tensile properties.

Computational fluid dynamics analysis of the fluid environment of 3D printed gradient structure in interfacial tissue engineering

Mass transport properties within three-dimensional (3D) scaffold are essential for tissue regeneration, such as various fluid environmental cues influence mesenchymal stem cells differentiation. Recently, 3D printing has been emerging as a new technology for scaffold fabrication by controlling the scaffold pore geometry to affect cell growth environment. In this study, the flow field within scaffolds in a perfusion system was investigated with uniform structures, single gradient structures and complex gradient structures using computational fluid dynamics (CFD) method. The CFD results from those uniform structures indicate the fluid velocity and fluid shear stress within the scaffold structure increased as the filament diameter increasing, pore width decreasing, pore shape decreased from 90° to 15°, and layer configuration changing from lattice to stagger structure. By assembling those uniform structure as single gradient structures, it is noted that the fluid dynamic characterisation within the scaffold remains the same as the corresponding uniform structures. A complex gradient structure was designed to mimic natural osteochondral tissue by assembly the uniform structures of filament diameter, pore width, pore shape and layer configuration. The results show that the fluid velocity and fluid shear stress within the complex gradient structure distribute gradually increasing and their maximum magnitude were from 1.15 to 3.20 mm/s, and from 12 to 39 mPa, respectively. CFD technique allows the prediction of velocity and fluid shear stress within the designed 3D gradient scaffolds, which would be beneficial for the tissue scaffold development for interfacial tissue engineering in the future.

An engineering approach to the 3D printing of K‐Carrageenan/konjac glucomannan hydrogels

SummaryAqueous solutions of Konjac glucomannan (KGM)/κ‐Carrageenan (κ‐C) of different ratios (1:2, 1:5, 1:8 and 1:10) and a fixed κ‐C content of 1.5%, were proposed as a new 3D food printing ink. Their thermo‐responsive behaviour was evaluated by temperature ramp rheological tests. This characterisation allowed for the evaluation of the synergistic effect between KGM and κ‐C and gave indications useful to the printing performance. Both elastic (G′) and loss (G″) moduli were found to increase by increasing the KGM concentration. Samples were printed by controlling the thermally reversible sol/gel transition occurring during the process. Direct pressure and flow rate measurements in the 3D printer were used to obtain the viscosity versus shear rate curves under processing conditions, useful to validate a scaling law relating the printing filament diameter to the relevant process and material properties (inks viscosity and printing pressure). The 3D printing performance of inks was evaluated by means of a novel, integrated score system. The results obtained indicate that aqueous mixtures of KGM/κ‐C can be successfully employed as a base for 3D printing food hydrogels. The use of the score system above outlined proved to be an easy yet efficient tool for the optimisation of the gel composition.

Thermomagnetic instability in superconducting lead-porous glass nanocomposites

In this paper we examine the mechanisms leading to thermomagnetic instability in nanostructured materials and study their regularities. The appearance of thermomagnetic instabilities in the superconducting state of various materials remains one of the problems of applications of superconductors. We studied the temperature and the magnetic field dependences of the magnetization m(T, H) and heat capacity C(T, H) of a nanocomposite consisting of interconnected lead filaments embedded in nanoporous glass (Pb-PG) with filament diameter d = 7 nm. Porous glass contains an arbitrarily orientated multiply connected system of pores of approximately the same size; lead in the nanocomposite forms a replica of the pore system. Thermomagnetic instability was previously observed in this material in superconducting state at T ≤ 5 K on m(H) dependencies in magnetization studies. We established that high enough external heater power P used during the heat capacity measurements in external magnetic field C(H) at T ≤ 5 K can initiate thermomagnetic instability and penetration of magnetic flux into the nanocomposite. The thermomagnetic instability is generally preceded by a sequence of small heat release events with the same magnitude as P. Another sequence of small heat release events is observed in the region close to Hc2. These events are presumably linked to the thermomagnetic instability process and are caused by small redistribution of magnetic flux in the nanocomposite.