Search

Polymer bonded explosives (PBXs) have high energy density, excellent mechanical properties and better thermal stability. In this study, droplet microfluidic technology was used to successfully prepare HMX/TATB microspheres. The effects of different binder types and binder concentrations on the morphology of the microspheres were studied, and results proved that NC/GAP (1:4) provides particles a regular spherical morphology and good dispersion. Subsequently, the influence of the concentration of the dispersed phase and the flow rate of the continuous phase on the particle size distribution of the microspheres was fully studied. The microspheres had narrow particle size distribution and high spherical shape. Under optimized process conditions, HMX/TATB microspheres were prepared and compared with the physical mixtures. The X-ray diffraction, differential scanning calorimetry, flow properties, bulk density, and mechanical sensitivity of the samples were also studied. Results showed that the crystal form of the microspheres remains unchanged, and the binder maintains good compatibility with explosives. In addition, the fluidity, bulk density, real density and safety performance of the microspheres are remarkably better than the physical mixture. This study provides a new method for preparing PBX with narrow particle size distribution, high spherical shape, excellent dispersion and high bulk density.

Microdroplets and their dispersion, with a large specific surface area and a short diffusion distance, have been applied in various unit operations and reaction processes. However, it is still a challenge to control the size and size distribution of microdroplets, especially for high-throughput generation. In this work, a novel ultra-high speed rotating packed bed (UHS-RPB) was invented, in which rotating foam packing with a speed of 4000–12000 r·min–1 provides microfluidic channels to disperse liquid into microdroplets with high throughput. Then generated microdroplets can be directly dispersed into a continuous falling film for obtaining a mixture of microdroplet dispersion. In this UHS-RPB, the effects of rotational speed, liquid initial velocity, liquid viscosity, liquid surface tension and packing pore size on the average size (d32) and size distribution of microdroplets were systematically investigated. Results showed that the UHS-RPB could produce microdroplets with a d32 of 25–63 μm at a liquid flow rate of 1025 L·h–1, and the size distribution of the microdroplets accords well with Rosin–Rammler distribution model. In addition, a correlation was established for the prediction of d32, and the predicted d32 was in good agreement with the experimental data with a deviation within ±15%. These results demonstrated that UHS-RPB could be a promising candidate for controllable preparation of uniform microdroplets.

The 5.0 vol.% GNP/2024Al composites were prepared by accumulated shear deformation combined with heat treatment, i.e. the thermomechanical treatment (TMT). The results showed that homogeneous distributed GNPs that aligned along the plastic deformation direction were obtained by six-pass drawing in the solution heat treatment state. The introducing of high-density dislocations in Al matrix by multiple drawing resulted in enhanced nucleation of precipitates and subsequent uniform growth during ageing. Consequently, ultra-strength GNP/2024Al composites, with yield and ultimate tensile strength 482 and 571 MPa, respectively, were achieved. The high strength was attributed to homogeneous dispersion of undamaged GNPs, fine and dispersed precipitations and work-hardening effect. This work demonstrated that TMT could act as a feasible strategy for preparing high-performance GNP/Al composites.

A laminated architecture with uniform dispersed graphene nanoflakes (GNFs) was elaborated in pure Ti matrix via a novel spray deposition method in conjunction with low-temperature consolidation strategy. The intrinsic structure of the aligned interlaminar GNFs was well-retained in the whole fabrication processes, and the appropriate interface reaction introduced a strong bonding between GNFs and Ti layers. In particular, the as-designed composite with 0.23 vol% GNFs exhibited the enhanced strength (+48.8% compared with the pure Ti laminates) without sacrifice in ductility. In-situ tensile tests indicated that the GNFs and interfacial TiC could effectively inhibited cracks propagation and relieved the strain concentration. The strengthening and toughening effects were induced by the synergetic effect of uniform dispersion, firmly interface bonding and laminated architecture. Together they act in concert to render outstanding mechanical performance. This study will highlight a simple and feasible route towards well balance between strength and ductility in Ti-based composites, and informative for achieving high-performance in nano-carbon/Ti system.

With the aim of remanufacturing high-value wear parts of shield tunneling machines, novel Fe-based composite coatings were prepared by collaborative modification with nano-TiC and nano-CeO2 particles. This work aims to improve the wear properties of Fe-based alloy coatings by regulating the morphology and dispersion of TiC through the addition of different contents of nano-TiC and nano-CeO2. First, the coatings with different contents of nano-TiC (from 5 wt% to 15 wt%) and nano-CeO2 (from 1 wt% to 2 wt%) were prepared by laser cladding. Subsequently, the microstructure, phase composition, microhardness, and wear properties of the coatings were examined. Furthermore, the wear morphology and the influence mechanism of nano-particles on the wear resistance of the coatings were investigated. It was found that the addition of nano-TiC eliminates the macro-defects of Fe55 alloy coating. Meanwhile, the morphology and dispersion of TiC particles in coatings were affected by the content of nano-TiC and nano-CeO2. Specifically, the addition of 1 wt% nano-CeO2 facilitates to the formation of near-spherical tiny TiC particles with low agglomeration in the coating. Therefore, the Fe55 + 10 wt% nano-TiC+1 wt% nano-CeO2 coating exhibits the best wear property among all the prepared Fe-based coatings. This paper provides theoretical guidance for the preparation of the modified Fe-based coating with excellent wear resistance.

The development of hypersonic precooled combined cycle engine provides a reliable power system for the future intercontinental navigation and reusable space orbital transportation. The compact heat exchanger precooler is the key component of the cooling cycle system, which provides efficient heat management for the hypersonic engine. This investigation mainly focused on the manufacturing process of precooler, and the typical structure of the precooler, ultrathin-walled capillary structure, was facilitated by the vacuum brazing using the particle reinforced composite filler alloy. The effects of different types and contents of the reinforced particle on the spreading behaviour, microstructural evolution, mechanical performance changes were investigated in detail. During the cooling process, the nucleation and growth of the γ-Ni solid solution on the surface of the reinforced particles was the main reason for the microstructure homogenization. Compared to the Ni particles, the more obvious mechanical properties improvement could be achieved by using IN718 particles reinforced composite filler alloy. The tensile strength and elongation of the brazed ultrathin-walled structure present 9.36% and 47.27% higher than that using initial filler alloy. Moreover, the micro-hardness distribution result revealed that the reinforced particles reduced the overall micro-hardness of the brazed region, dispersed the eutectic structure and increased the hardness dispersion, which would reduce the stress concentration tendency and improve the structural properties.

Aluminum-based composite abradable seal coatings are pivotal to improving the efficiency of aero engines or gas turbines. However, the adhesive transfer frequently occurs between metallic blade tips and aluminum-based composite coatings, resulting in engine vibration and even jam. Many past studies had tried to solve this problem by reducing coating hardness, improving lubrication, or strengthening blade tips, but all had failed. In this paper, we proposed a novel epoxy-based composite abradable seal coating, eliminating adhesive transfer by changing metal-to-metal scraping pair to metal-to-polymer scraping pair. The coating was developed via a hierarchical structure design. Large spherical pores were uniformly distributed in the continuous epoxy matrix with fine graphite dispersion. By adding 20 vol.% graphite and 50 vol.% hollow microspheres, a self-lubricating epoxy-based coating of 0.26 friction coefficient with thermal conductivity of 0.28 W/(m·K), coating HR15Y hardness at 54.8, and bonding strength at 18.7 MPa can be reached. When the metallic blades scrape the epoxy-based composite coating, no adhesive transfer occurs. Besides, a smooth scraped surface is formed by pseudoplastic deformation. This epoxy-based composite abradable seal coating opens a new way to improve the efficiency and reliable operations of air engine compressors.

Objectives To develop and test the cutting efficiency of a novel degradable glass as an alternative media to alumina powder for air abrasion. Materials and methods A zinc-based glass (QMZK2) was designed, produced, and evaluated with a multi-modality imaging analysis. The glass dissolution study was carried out in three acids, using ICP-OES (inductively coupled plasma optical emission spectroscopy) at 5 different time points: 2.5, 5, 10, 60, and 240 min. The cutting efficiency of both materials was tested under the same parameters on slabs of elephant enamel. A stained fissure of a molar tooth was air abraded with the glass and evaluated with X-ray micro-tomography before and after air abrasion. Results The particle size distribution of the glass was similar to that of alumina 53 µm but with a slightly greater dispersion of particle size. The shape of the particles was angular, appropriate for cutting purposes. The dissolution study showed that the glass dissolved rapidly in acidic conditions at all time points. Between the two variables, pressure and powder flow, pressure was found to influence the cutting speed to a greater extent than powder flow. Conclusions Alumina powder was found to perform significantly better in 4 of the 9 conditions tested on elephant enamel, QMZK2 in one, and no significant differences were found for the rest of the 4 conditions. The QMZK2 seems to offer promising results as an alternative material to alumina. Clinical relevance. QMZK2 glass has the potential for replacing aluminum oxide as a degradable material in air abrasion technology.

Bipolar plates (BPs) for fuel cell applications must meet minimum conductivity requirements while maintaining light weight and sufficient mechanical strength to be thinned and easily fabricated. Here, we prepare BPs comprising fluorinated ethylene–propylene (FEP), graphite flakes (GFs), graphite nanoplates (GnPs), and silicon carbide (SiC) particles for fuel cell applications. SiC particles decorated on large GFs and GnPs improve the flexural strength of the composites relative to the corresponding composites without SiC, resulting in increases of ∼24% and ∼130%, respectively. The improved mechanical properties of the FEP/GnP/SiC and FEP/GF/SiC composites are due to the uniform dispersion of SiC particles and strong chemical bonding between GF (or GnP) and SiC particles in the FEP matrix. Incorporating SiC particles into the FEP/GnP (or GF) composite plate provides a robust, scalable strategy for realizing high-performance, high-temperature fuel cell BPs.

This experimental study emphasizes on the effect of ultrasonication, degassing and stirring process of purenanotubular Halloysite (HNT) on epoxy based composite. This process includes hydraulic compression and moderate pressurized hold under a pressure of 1.1 MPa for the expansion restriction of the composite during solidification. Synthesized composite were evaluated accordance to the processing effect on the microstructure and its interfaces. A compact discussion on the microstructure of the each composite and generated interface has been illustrated. A consolidated effect of processing parameters as ultrasonication, degassing and stirring is observed on the microstructure and XRD results of the synthesized composite. Microstructure results reveal that dispersion of HNT enhanced linearly with an addition of HNT particulates.

The void level of a component produced by additive manufacturing can be used to predict the mechanical properties and in most cases it is important to develop processing methodologies able to minimize it. Conventional techniques include parameter optimization and the hot isostatic pressing (HIP). However, in the former there is a limit where improvement becomes minimal and the latter, although it is effective for internal voids, is not efficient in the case of voids located near the surface, which are considered critical. This paper describes a study in which laser remelting was used as an alternative to achieve higher densification after processing using directed energy deposition with laser (DED-L). This technique has been investigated for powder bed (PB) processes, but has not been explored for DED. Understanding the behavior of different materials considering the same processing parameters is also relevant and has not been previously addressed. An ytterbium (Yb) fiber laser with a maximum nominal power of 10 kW and wavelength of 1070 nm was used. Iron and Inconel 625 powders were deposited on an SAE 1010 steel substrate to form beads with intentional voids. The DED-L was performed with a power of 450 W, scanning speed of 600 mm/min and powder feed rate of 10 g/min. The laser radiation was applied over the produced surface at three energy levels: 31.5 kJ/m, 38.2 kJ/m and 45 kJ/m. An in-house MATLAB image processing code was developed in order to assess the void percentage. The results indicated that most of the voids originating from the DED-L process were due to lack of fusion between beads and between the deposit and the substrate. For iron, the void percentage after DED-L varied between 5.3% and 7.1%. After remelting, this value reduced to 1.7% applying 45 kJ/m. It was also noted that in all samples the voids that were initially connected to the surface coalesced because of material redistribution. However, a low repeatability was observed. For Inconel, the void percentage after DED-L varied between 4.4% and 7.1%, and reduced to 3.7% applying 31.5 kJ/m. This reduction is not as significant as that observed for iron and also the degree of dispersion was lower for iron. Hence, laser remelting is able to mitigate voids resultant from DED-L and, consequently, achieve better quality due to a lower probability of component failure. Simultaneously, productivity can be enhanced since the equipment required is the same as that used for the deposition. However, new strategies are needed to increase the process robustness and reduce the degree of dispersion.

Machining of materials is an important operation in the manufacturing industry to develop components and structures. Compared with metals and alloys, metal matrix composites (MMCs) respond differently during machining due to the presence of different phases possessing heterogeneous physical and mechanical properties. In the present study, the machining behavior of Al6063-SiC composites has been investigated to assess the role of dispersing phase on machining characteristics. Composites with varying SiC content (4% and 8% by wt.) were produced by stir casting. From the microstructural studies, decreased grain size was observed with increased SiC dispersion. Higher hardness was measured for the composite with 4% SiC. From the machining studies during turning experiments, the variations within the cutting forces were found to be higher for the composites compared with the base material. Cutting forces were also measured as increased with the increase of SiC content. The results suggest that the presence of SiC influences the machining behavior of Al6063-SiC composites which is a valid factor must be considered while performing turning operation.

In this study, based on the fiber-reinforced tailing recycled aggregate concrete, the effects of the metakaolin (MK) content on the mechanical performance were investigated. The pore structures and strain development of concrete were obtained by nuclear magnetic resonance (NMR) and digital image correlation (DIC). In addition, the enhanced effects of MK on concrete matrix were further studied at the micro level. The results uncovered that MK addition significantly improved the cubic compressive strength, axial compressive strength, splitting tensile strength and peak strain. The best performance was obtained by the mix that contained 10% MK. The NMR results showed that MK substitution led to decreased numbers of pores and a coarsening of micropore structure of concrete. The harmless pores (pore radius range 0–0.2 μm) were the most important parameter affecting the compressive strength. The DIC results indicated that the presence of MK particles favored the dispersion of polypropylene fibers in the concrete matrix. Microscopically, the addition of MK promoted the hydration process of matrix, leading to enhanced bonding between fiber and matrix.

The processing scale and mechanical properties of graphene (Gr) reinforced metal matrix composites are highly desired for a wide range of critical applications. However, a long-standing problem is that Gr possesses poor dispersibility and weak interfacial strength with the metal matrix. In this work, we offer an in-situ liquid metallurgy strategy for fabricating Mg matrix composites with excellent modulus, strength and plasticity by a chemical reaction between carbon dioxide (CO2) and Mg melt. This processing route enables the in-situ synthesis and modification of Gr in the metal melt simultaneously, which yields an optimal microstructure including uniform dispersion of Gr and strong interfacial bonding between Gr and Mg matrix. This novel approach can be readily adapted to large-scale industrial production of Mg matrix composites and even offers a general design pathway for manufacturing metal matrix composites.

With the emergence of 5G communication and the rapid development of the microelectronics industry, the heat dissipation of high power circuits has become quite an important issue. Along these lines, the thermal conductivity distribution of the electronic packaging materials, which plays a key role in the protecting circuits, requires urgent improvement. In this study, amino-functional boron nitride nanosheets (BNNS) were prepared by employing ball milling boron nitride with urea (aqueous solution) as agents. Then, the epoxy composites filled with large size pristine boron nitride (pBN) and small size functional boron nitride were fabricated by using the wet ball-milling (wBN) technique. The acquired results indicate that the thermal conductivity property of the pBN/wBN/epoxy composites with pBN/wBN ratio of 2.5/7.5 can reach the value of 0.386 W/mK, which is 96% higher than that of pure epoxy. Meanwhile, the measured value is superior from both the pBN/epoxy and wBN/epoxy composites with the same filling amount. This effect can be attributed to the efficient construction of the fillers network and thermal conduction path. Within the epoxy matrix, wBN can fill the pores between pBN and form a denser filler network. In addition, the amino-functional groups grafted with wBN result in their enhanced dispersion within the epoxy matrix that leads to a more stronger interfacial effect. Our approach provides useful insights in understanding the incorporation mechanisms of fillers in polymers, and thereby enhancing their potential applications.

Carbon/silicon carbide (C/SiC) composites are usually regarded as thermal protective system materials and widely applied in hypersonic vehicles or ramjet. However, poor thermal conductivity of C/SiC composites, leading to severe heat concentration and thermal stress during the high-speed operation of hypersonic vehicle, limits their broad-range of practical applications. Modification with high thermal conductive fillers is an optional method; however, controllable dispersion and orientation of the fillers to construct continuous and ordered heat conductive channel has been proven to be a challenging task. Herein, based on high thermal conductivity fibers, a three-dimensional micro-pipeline preform was developed for the preparation of structure–function integrated C/SiC composites. The technical feasibility of the method, the characteristics of microstructures, and the thermal conductivity and bending strength of the as-obtained composites were systematically studied. Results revealed that the thermal conductivities of as-obtained composites reached 150.2 and 46.7 W m−1 K−1 for in-plane and out-of-plane direction, respectively. The bending strength obtained herein is 264.4 MPa, which is lower than that of polyacrylonitrile C/SiC composites. However, the fine control over the component and microstructure or densification could provide a higher value in the future research. In sum, the proposed method provides a convenient and feasible approach to prepare high thermal conductive C/SiC composites.

Conventionally, Te has primarily been used to improve the machinability of steel and its alloys. In this work, Te was used to refine the grains of an oxide-dispersion-strengthened (ODS) steel produced by additive manufacturing (AM) with fixed processing parameters. Addition of Te to the raw powder produced an ODS steel with a fine-grained microstructure, in contrast to the ODS steel manufactured without Te. Moreover, the addition of Te resulted in superior yield strength and ultimate tensile strength, which was attributed to the combined effects of grain refinement and the finer nanoparticles (NPs) composed of Te-rich composite NPs and Cr-rich NPs. For the first time, the AM technique was used to obtain grain and nanoparticle sizes of ~3.4 µm and 6 nm, respectively, from the Te-added ODS steel

To solve the problem of non-magnetic inclusion in concentrates and magnetic inclusion in tailings in the separation process of micro-fine magnetite, a novel permanent magnet pulsating separator (PMPS) was developed, employing the agglomeration mechanism of magnetite particles, and the dispersion mechanism of gangue minerals, whose magnetic poles arranged in a rectangular manner on plates on both sides of a separation chamber, and with alternating strong and weak magnetic fields generated in the separation area by reciprocating the plates. The magnetic field intensity was simulated by Infolytica Magnet software to optimise the parameters of the magnetic system. Laboratory PMPS was used to carry out tests on Sample I with a total iron (TFe) grade of 53.9% and an 89.83% passing size of 0.074 mm, and on Sample II assaying TFe 62.8% with a 75.21% passing size of 0.02 mm, and the operational parameters were optimised. Results indicated that PMPS upgraded Sample I and Sample II correspondingly to TFe 63.5% with a recovery of 87.1%, and to TFe 68.1% with a recovery of 92.0%, suggesting its amenability for the cleaning stage. If required, the separation chambers and magnetic systems of PMPS can be superimposed parallelly in the horizontal direction to allow for flexible enlargement of the processing capacity, characteristics of a simple structure, small occupation area, and large processing capacity.

An acceptable viscosity and an easy penetrability of cement - limestone filler grout in the granular matrix of self compacting concrete are an important factors that affecting both its rheological and its hardened properties. This experimental and theoretical work consists to study the effect of limestone filler fineness on the rheological behavior of cement - limestone filler grout. In the first part, five different grouts were prepared by varying the Blaine Specific Surface (BSS) of the limestone filler, 3060, 4750, 6320, 7680 and 9440 cm2/g, respectively. A large number of properties relating to the rheology and the stability are carried out on the five grouts such as grain dispersion, density, volume concentration of solid, dynamic viscosity and Marsh funnel flow. The second part consists to develop a theoretical model to predict the different rheological properties of the grout as function of limestone filler BSS. The results show that the rheological properties of cement-limestone filler grout such as the dispersion percentage, the intergranular distance and the flow time are strongly affected by the limestone fillers fineness. In addition, the experimental and the predicted results present a good agreement.

In order to develop a highly efficient, simple-preparation and renewable explosion suppressant of composite powders, the superfine NaHCO3-shell powder (S-S) composite explosion suppressant was prepared by one-step method with airflow crusher to fulfill the mechanical dry coating of shell powder by NaHCO3, which solved the contradiction between dispersion and suspension force of explosion suppressant particles. The composition optimization and performance test of S-S composite explosion suppressant were carried out with the use of 20 L explosion tank and large tubular coal dust characteristics identification instrument. The results show that when the shell powder particles are coated with NaHCO3, the overall water absorption performance of the powder is reduced, the particle agglomeration phenomenon is weakened, and the dispersion is obviously improved. With the increase of NaHCO3 ratio, the ignition sensitivity of coal dust decreases, and the time to reach the first explosion Pmax is gradually delayed, and both Pmax and (dP/dt)max decrease. With the following explanations: NaHCO3 has a significant effect on reducing (dP/dt)max due to its chemical reaction, while shell powder is beneficial to reducing the Pmax due to its physical barrier effect. The suppression effect of S-S composite explosion suppressant on coal dust explosion is far better than that of pure NaHCO3 or shell powder.

The abrasive wear response of Al-7.5Si–SiC composite produced by stir casting technique was examined and compared to Al-7.5Si alloy (matrix alloy) and Al-17.5Si (low-cost hypereutectic) alloy in as-cast and after heat treatment. The microstructure of the hypereutectic alloy shows the α-Al, α-Si, and Al-Si eutectic phases, and the microstructure of the composite shows the homogeneous dispersion of SiCp in the matrix and excellent bonding of the Al-SiC interface. The wear examinations were performed on pin-on-disc apparatus at 38–80 µm abrasive (grit) sizes, 5–20 N applied loads, 100–400 m sliding (abrading) distances, and 1 m/s constant sliding speed. At 80 µm size of abrasive and 20 N of the applied load, the decrement in wear rate of LM30 alloy and LM25-SiCp composite was 31.82% and 95.37%, respectively, in case of the as-cast condition. However, for heat-treated conditions, the decrement in wear rate of hypereutectic alloy and composite was 32.63% and 96.61%, respectively. The wear rate of specimens was increased with abrasive size and applied load. The wear resistance of the hypereutectic alloy was superior to the matrix alloy but inferior to the composite irrespective of the abrasive size and applied load. The wear surface of the specimens, abrasive papers, and wear debris were analysed by the field-emission scanning electron microscope (FESEM) for the wear mechanism.

This paper investigated the effect of magnesium as a dispersion strengthening material on some mechanical properties of 1200-Aluminium (Al-Fe-Si) alloy, a typical commercial aluminium alloy used in the production of household utensils. 1200-Aluminium (Al-Fe-Si) alloy containing varying percentages of the dispersion hardening material (i.e. Magnesium) were produced and mechanical tests namely; hardness, tensile strength and impact strength were carried out. Also, the microstructures of the cast materials were studied. The results showed that increase in magnesium content, as dispersion hardening material improved the hardness, tensile strength and caused a slight decrease in impact strength of the 1200-Aluminium alloy. It is inferred from this work that using magnesium as a dispersion hardening material brings about corresponding improvement in some mechanical properties of 1200-Aluminium (Al-Fe-Si) alloy. Keywords: Magnesium, Aluminium alloy, dispersion strengthened, reinforced alloy, crystallographic formation Depth, Geothermal Energy

This paper reports the dispersion of nanoclay in vinylester using co-rotating twin screw extrusion and ultrasonication for preparing nanoclay/vinylester gel coat. Two sets MMT/vinylester specimens, namely Type 1 and Type 2 were prepared for comparative studies. While Type 1 specimens were prepared using ultrasonication only, Type 2 specimens were prepared using both ultrasonication and twin-screw extrusion. Type 2 specimens showed lower levels of nanoclay intercalation and higher levels of exfoliation. By using the MMT/vinylester gel coat so prepared by the two different routes, MMT/vinylester/glass specimens were fabricated and tested for mechanical properties. Type 2 based nanocomposite specimens showed greater values of ultimate tensile strength, flexural strength, interlaminar shear strength and impact strength. Scanning Electron Micrographs (SEM) of tensile fractured Type 2 based specimens showed less agglomeration of nanoclay than that of Type 1 based specimens.

The structure of the AA5056-Al3Er composite and the initial alloy was studied by optical and scanning electron microscopy. The introduction of 0.23 wt.% particles does not modify the structure of the aluminum alloy, but, due to dispersion hardening, increases the ultimate tensile strength and ductility of the metal matrix. Rolling the AA5056-Al3Er alloy leads to a more uniform distribution of particles in the volume of the material, but does not increase its yield strength or ultimate tensile strength. A more uniform distribution of deformation due to the influence of Al3Er particles made it possible to increase the ductility of the AA5056 alloy.

Pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) is a promising alternative technique due to its stability, simplicity and cost of operation. This is an efficient process due to its high surface area for extraction as well as stripping, and low energy consumption for creating the pseudo-emulsion and for the separation of phases. This technique takes the combine advantages of emulsion liquid membrane and overcomes the sufferings of membrane stability in the supported liquid membrane systems. Present work includes extraction of neodymium (III) (Nd) by using TODGA and HNO3 as the extractant cum strippant in PEHFSD technique. A model is developed to study the transport of Nd under different hydrodynamic and chemical conditions that includes organic ratio (A/O) in dispersion, effect of speed of impeller on drop size formation, effect of feed acidity, effect of carrier concentration, effect of feed flow rate. A code is written to solve the model equations numerically to predict the concentration of the feed reservoir with time. Experiments are conducted to obtain the best optimum extraction conditions. Results obtained from the numerical simulations are validated with the experimental data and found a good agreement between them.

Carbon nanomaterials were used to enhance desired properties of polymeric matrices. Combining varied carbon nanofillers with dissimilar dimensions can lead to synergy through effective dispersion. In this work, mechanical, thermal, acoustic, and dielectric properties of polyurethane (PU) hybrid nanocomposites were investigated. PU containing multi-walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNPs) were used to evaluate the effects of single and hybrid nanofillers on the final properties of nanocomposites. The results showed a synergistic effect between nanofillers, in which the hybrid nanocomposites exhibit better performance, relative to the single inclusion of the nanofillers. These hybrid nanofillers improved dispersion quality in the polymer matrix due to the formation of a GNPs/CNTs 3D architecture, in which tensile strength, thermal conductivity, acoustic transmission loss, and dielectric constant of PU were enhanced by about 43%, 5%, 51%, and 13% at 0.25 wt% loadings, respectively. The overall properties of the hybrid nanocomposite revealed the superiority over the single nanofiller system in multifunctionality, evaluated by a performance index.

A simple mechanical vibration was used to enhance interface bonding of the Al/Mg bimetallic composites produced by a novel lost foam compound casting in this study. The effect of vibration time on interfacial microstructure and mechanical properties of the Al/Mg bimetallic composites was investigated. The results show that the vibration time had a significant effect on the interfacial microstructure and mechanical properties of the Al/Mg bimetallic composites. With the increase of the vibration time, the cooling rate during the solidification was increased, and the thickness of intermetallic compounds (IMCs) layer at the interface of the Al/Mg bimetallic composites was decreased. This resulted in the decrease of A3Mg2 and Al12Mg17 brittle phases, and the Mg2Si phase at the interface was refined with a distribution change from agglomeration to dispersion. When the vibration time was 300 s, the vibration fully affected the formation and solidification process of the IMCs layer of the Al/Mg bimetallic composites, and had an obvious effect on the reduction of the brittle phases as well as the improvement of the size and distribution of the Mg2Si phase. As a result, the shear strength of the Al/Mg bimetallic composites was the highest, reaching 47.49 MPa, which was 51% higher than that of the Al/Mg bimetallic composites without vibration.

The present work investigates the effect of ultrasonic power (%) and the time of ultrasonic vibration on the sintered density and ultimate compressive strength (UCS) of Mg15Nb3Zn1Ca fabricated using ultrasonic assisted conventional sintering (UACS). The customized UACS setup was designed and manufactured to conduct the experimentations. A customized ultrasonic stepped horn assembly was used for providing vibrations to the sample during sintering. Further, to evaluate the efficacy of ultrasonic vibration parameters, the developed setup was used to sinter Mg15Nb3Zn1Ca composite material. The study unveiled an increased sintered density and UCS of the fabricated sample by the increase in ultrasonic power (%). Moreover, a decrease in sintered density and UCS was observed with an increase in the time of ultrasonic vibration beyond a certin limit. Samples sintered with the assistance of ultrasonic vibration at 100% ultrasonic power, and 20 min of ultrasonic vibration resulted in a sintered density of 1.928± 0.062 g·cm−3 and UCS of 234.9± 12.3 MPa. The obtained mechanical properties of the fabricated sample were comparable to the properties of cortical bone. The surface morphology and elemental compositions of samples fabricated using UACS declared a fair dispersion of reinforcement in the matrix containing merely the source elements. The results of corrosion test have showed that the assistance of ultrasonic vibration suppressed the degradation behaviour of the sintered sample after performing electrochemical study of samples using 3-electorde cell voltammetry. Mg15Nb3Zn1Ca fabricated using UACS showed a 50.18% and 9.08% of reduction in corrosion rate over conventionally sintered pure Mg and Mg15Nb3Zn1Ca respectively. In addition, electrochemical impedance spectroscopy (EIS) results indicated an enhanced corrosion resistance of the Mg15Nb3Zn1Ca composite material when fabricated at 100% of ultrasonic power with 20 min of vibration time. Apart from that, electrochemical equivalent circuits also resulted in good fitting of the experimental data obtained from EIS.

In this paper, the microhardness of the AZ91D matrix in Cf-SiCNWs/AZ91D composites is investigated. It is found that introducing SiCNWs into composites can increase the microhardness of the AZ91D matrix close to the SiCNWs (the vertical distance does not exceed 100 μm from the SiCNWs), which is as high as 84.34 HV and is 36.78 % higher than that of the alloy far away from the SiCNWs. The SiCNWs/AZ91D zone has the highest average microhardness (103.76Hv), which is 68.28 % higher than that of the AZ91D alloy in the Cf-SiCNWs/AZ91D composite. The increase in microhardness of AZ91D matrix is attributed to the synergistic effect of several reasons, including the increased dislocation density, the uneven dispersion of aluminum element caused by SiCNWs, as well as the nanocrystals of Mg17Al12 precipitates.

Phase Change Materials (PCMs) have being used in different solar energy systems for thermal energy storage and performance enhancement. Improving heat transfer from PCMs leads to reductions in charge and discharge durations, which makes them more favorable as storage units. Dispersion of conductive solid materials with nano dimensions is a practical approach to enhance their thermal features. Several nano-sized materials have been added to PCMs to improve their heat/cool storage abilities. The studies in this field reveal that employing nanotechnology is an efficient method for heat transfer improvement. In the current article, studies concerning applications of nanotechnology in PCMs are reviewed. According to the results, employing nanotechnology can noticeably enhance the heat transfer rate, which results in a reduction of charge and discharge times of the storage units equipped with the PCMs. The enhancement in the melting process of nano PCMs, which indicates the storage performance, depends on several factors such as concentration and kind of solid nano-sized particles, type of base PCM and the parameters related to operating conditions such as Rayleigh and Darcy numbers. The improvement in thermal performance due to nano PCMs is mainly attributable to the increased thermal conductivity and decrease in latent heat of fusion, which accelerates the melting/solidification processes.

Mathematical analysis of experimental data for low-alloy steel 09G2S austenite recrystallization after hot rolling is provided. An original mathematical model is proposed that relates the volume fraction of recrystallized structure to degree of hot deformation, temperature, and recrystallization annealing duration. The prediction accuracy for this model evaluated in terms of dispersion of deviation for experimental data from predicted results standardized for the average value of experimental results comprises ≈ 20%.

Based on the unique structure, excellent physical and mechanical properties of graphene nanosheets (GNSs), thermal decomposition method was used to modify the GNSs for preparing Ni-modified GNSs (Ni-GNSs) in this paper. Varying amounts of Ni-GNSs were added to SnAgCuRE solder alloy to synthesize composite solders. The soldering behaviors of the composite solders were studied, and the strengthening mechanism of Ni-GNSs on the SnAgCuRE lead-free solder/Cu joints was discussed. Compared with Sn2.5Ag0.7Cu0.1RE0.05Ni solder alloy joint, the interfacial IMC morphology of Ni-GNSs/SnAgCuRE composite solder joints changed from cobblestone to cobblestone and short bar, the interfacial IMC layer thickness was smaller, the IMC grains and microstructure of solder joints were refined. The addition of GNSs changed the structure of the composite solder/Cu joints, and formed a subinterface area enriched with Ni-GNSs between the interfacial IMC and the soldering seam, which helped enhance the reliability of the composite solder joints through the dispersion strengthening of solder by GNSs. Meanwhile, the fracture location of the solder joint was in the soldering seam, so strengthening the solder alloy was also beneficial to improving the strength of the solder joints. After modified by Ni, GNSs was combined with β-Sn matrix to produce a good semi-coherent interface by the bridging action of Ni, revealing a new mechanism of interface strengthening between Ni-GNSs and β-Sn matrix in Ni-GNSs/SnAgCuRE composite solder, which contributed to the improvement of shear strength of composite solder joints.

In this research, Y2O3 nano particles were dispersed into Aluminum A356 via ultrasonic assisted stir casting route. Microstructural analysis confirmed that ultrasonic aided synthesis significantly helped in homogenous dispersion of particles; excellent bonding between matrix and reinforcement and at the same time significantly refined the dendritic microstructure. Addition of nano Y2O3 particles and ultrasonic treatment had a tremendous impact on the hardness of developed composites. Sliding wear characteristics of the developed composites were investigated under varying sliding speeds and loads. Wear test results confirmed that addition of nano Y2O3 particles comprehensively decreased the A356 alloy wear rate, and SEM analysis of the worn out samples revealed delamination, oxidation and abrasion, plastic deformation wear to be the predominant wear mechanisms.

Актуальность исследования обусловлена отсутствием эффективных методов и средств борьбы с загрязнением атмосферы субмикронными частицами размером менее 2,5 мкм. Применяемое для этих целей ультразвуковое воздействие не позволяет обеспечить степень укрупнения дисперсных частиц, достаточную для их осаждения или улавливания существующим газоочистным оборудованием. Как показывают экспериментальные исследования, даже при максимальном уровне звукового давления (при превышении которого инициируется обратный процесс - диспергирование капель или разрушении агломератов частиц) эффективность ультразвуковой коагуляции оказывается недостаточной, особенно при малой счетной концентрации частиц. Это обуславливает необходимость выявление новых физических эффектов и разработки новых способов воздействия, повышающих эффективность коагуляции тонкодисперсных частиц. Цель: разработка способа для повышения эффективности ультразвуковой коагуляции частиц размером менее 2,5 мкм за счет формирования вихревых акустических течений в тонком воздушном промежутке между излучателем и отражателем и создание устройства для его практической реализации. Результаты. Предложен новый способ и устройство для очистки газов от дисперсных частиц размером менее 2,5 мкм за счет увеличения времени ультразвукового воздействия на каждую частичку и создания зон локального увеличения концентрации субмикронных частиц. Это обеспечивается за счет формирования вихревых потоков между излучающей (в виде изгибно-колеблющегося диска) и отражающей поверхностями. Локальная зона повышенной концентрации частиц формируется в периферийной области вихря за счет дрейфа частиц под действием центробежных сил из центральной области вихря к его периферии. Предложенный способ обеспечивает повышение эффективности с 13 до 50 %, в зависимости от исходной концентрации дисперсных частиц. The relevance of the research is caused by the lack of effective methods and means of combating atmospheric pollution with particles less than 2,5 microns in size. The ultrasonic effect used for these purposes does not allow ensuring the degree of coarsening of dispersed particles sufficient for their sedimentation or capture by the existing gas cleaning equipment. Experimental studies show that even at the maximum sound pressure level (above which the reverse process - the dispersion of drops or the destruction of particle agglomerates - is initiated), the efficiency of ultrasonic coagulation is insufficient, especially at a low counting concentration of particles. This necessitates the identification of new physical effects and the development of new methods of ultrasonic exposure, providing an increase in the efficiency of coagulation of fine particles. The main aim: development of a method for increasing the efficiency of ultrasonic coagulation of particles less than 2,5 microns in size due to emerging vortex acoustic flows in a thin air gap between the emitter and the reflector and a device for its implementation. Results. The authors have proposed a new method and device for cleaning gases from dispersed particles less than 2,5 microns in size by increasing the time of ultrasonic action on each particle and creating zones of local increase in the concentration of fine and submicron particles. This is provided by the formation of vortex flows between the emitting (in the form of a flexural-vibrating disk) and the reflecting surfaces. A local zone of increased concentration of particles is formed in the peripheral region of the vortex, due to the drift of particles under the action of centrifugal particles from the central region of the vortex to its periphery. The proposed method provides the increase in efficiency from 13 to 50 %, depending on the initial concentration of dispersed particles.

Metal/carbon nanotube (CNT) composites are promising functional materials due to the various superior properties of CNTs in addition to the characteristics of metals, and consequently, many fabrication processes of these composites have been vigorously researched. In this paper, the fabrication process of metal/CNT composites by electrochemical deposition, including electrodeposition and electroless deposition, are comprehensively reviewed. A general introduction for fabrication of metal/CNT composites using the electrochemical deposition is carried out. The fabrication methods can be classified into three types: (1) composite plating by electrodeposition or electroless deposition, (2) metal coating on CNT by electroless deposition, and (3) electrodeposition using CNT templates, such as CNT sheets and CNT yarns. The performances of each type have been compared and explained especially from the view point of preparation methods. In the cases of (1) composite plating and (2) metal coating on CNTs, homogeneous dispersion of CNTs in electrochemical deposition baths is essential for the formation of metal/CNT composites with homogeneous distribution of CNTs, which leads to high performance composites. In the case of (3) electrodeposition using CNT templates, the electrodeposition of metals not only on the surfaces but also interior of the CNT templates is the key process to fabricate high performance metal/CNT composites.

Rice husks (RHs) are rich in silica and organic carbon components, which have been widely applied in lithium ion batteries. However, the natural structure of uneven dispersion between SiO2 and amorphous C in RHs leads to poor electrical conductivity and structural integrity. In this work, SiO2/C composites were prepared by mechanical mixing and high-temperature carbonization from RHs, with coal tar electronic pitch (CTEP) or polyvinyl chloride (PVC) as the carbon coating agent, which imparted some improvement in cycling performance, initial coulombic efficiency (ICE), and rate performance. Compared with the high electrical conductivity of CTEP, PVC with low viscosity coated uniformly the surface of BM-SiO2/C, which is beneficial to providing both elastic and mechanical stability and keeping the structural integrity. BM-SiO2/C-PVC-6 exhibits a more stable cycling performance and higher specific capacity of 730 mA h g-1 after 100 cycles at 0.1 A g-1, with the ICE of 60%. Hence, the application of carbon coating agent plays a vital role in improving the electrochemical performance of SiO2/C composites. PVC with excellent coating performance was selected to coat RHs-SiO2/C and the electrochemical performance was enhanced, which provides a method of converting biomass material into a useful storage device.

To verify the performance of self-developed high viscosity modified (HVM) asphalt binder with styrene–butadiene–styrene (SBS) composite modifier, the various branched and linear SBS modifiers with different mixing ratios were selected to prepare HVM asphalt binder, and the mix proportion of SBS modifier in HVM asphalt binder was also optimized. The fluorescence microscope, multiple stress creep recovery (MSCR) test, bending beam rheometer (BBR) test, improved boiling water test and viscosity test were used in this study, and the different properties of HVM asphalt binder with SBS composite modifier, HVM asphalt binder with linear SBS modifier, HVM asphalt binder with Tafpack-super (TPS) modifier (TPS-HVM asphalt binder) and HVM asphalt binder with SINOTPS modifier (SINOTPS-HVM asphalt binder) were evaluated. The results show that the mixing ratio of linear SBS modifier and branched SBS modifier in the composite modifier is 2:1, the dispersible uniformity and road performance of HVM asphalt binder with the composite modifier are better, and the modification of composite modifier with SBS-1301 and SBS-4303 modifier is greater than LG-501 and LG-411, LCY-3501 and LCY-3411. The performance of HVM asphalt binder with the composite modifier was significantly influenced by the mix proportion and structure of SBS modifier. The dispersion effect of SBS modifier is superior to TPS and SINOTPS additive. The high-temperature performance, adhesion and viscosity of HVM asphalt binder can be increased by addition of SBS composite modifier, but the low-temperature performance of HVM asphalt binder is decreased slightly. The flexibility of HVM asphalt binder with linear SBS modifier at low temperature is better than SBS composite modifier. Compared to TPS-HVM and SINOTPS-HVM asphalt binder, the low-temperature performance and adhesion of HVM asphalt binder with SBS composite modifier are relatively good, while the viscosity of HVM asphalt binder with SBS composite modifier under high temperature is lower. The elasticity of different HVM asphalt binders decreases in order SINOTPS-HVM asphalt binder, HVM asphalt binder with SBS composite modifier and TPS-HVM asphalt binder. This study will be provided more options for the asphalt binder of porous asphalt pavement and steel deck pavement.

In this present investigation, the thermal and swelling behaviour of cellulosic fibre reinforced ZrO2-dispersed unsaturated polyester composites is evaluated. Cellulosic fibres (jute and sisal) with chemical treatment and ZrO2 particles are dispersed within an unsaturated polyester matrix with a filler loading of 5–45 wt.% by compression moulding technique. The electronic thermal insulation tester, differential scanning calorimeter, thermo-gravimetric analyser, and limiting oxygen index analyser are used for thermal analysis of the composites. Various solutions with different pH values are used for the investigation of the swelling tendency of the composites. A marked enhancement in thermal and swelling properties is noticed along with the inclusion of fillers within the unsaturated polyester matrix. The fabricated composites displayed optimum results for filler content with 35 wt.% followed by saturation in properties with the dispersion above the same.

In this study, composite consisting of thermally exfoliated g-C3N4 nanolayer/N, Gd, and Fe co-doped TiO2 (N-Gd-Fe-TiO2/g-C3N4) was successfully fabricated by a facile in situ synthetic method. The effects of nanometer heterojunction on the structure, chemical composition, light absorption property, and carrier transport of the hybrid composites were systematically studied. The amount of g-C3N4 nanosheets in the composites plays a crucial role in regulating the dispersion structure and morphology of the composites. Among the synthesized N-Fe-Gd-TiO2/g-C3N4, the sample with 3.4wt% of N-Gd-Fe-TiO2 in the composite, denoted as 3.4%GFNT/CN, exhibited an ideal heterojunction structure, and showed the highest photocatalytic rate of 98.3%, which is 1.68 and 1.42 times to that of N-Gd-Fe-TiO2 and exfoliated g-C3N4 nanosheets, respectively, and its rate constants are 5.6 and 4.4 times than that of N-Gd-Fe-TiO2 and exfoliated g-C3N4 2D nanosheets, respectively. The narrow band gap and weak photoluminescence peak intense of 3.4%GFNT/CN demonstrated the formation of well-contacted nanoscale heterojunctions in the composites. The heterojunction structure widened the light response wavelength of the catalyst, and simultaneously promoted the efficient separation of the photogenic carriers, therefore enhanced the photocatalysis performance of the resulting composite. N-Gd-Fe-TiO2/g-C3N4 composite was successfully synthesized and displayed superior electron–hole separation efficiency and photocatalytic activity owing to the heterojunction structure.

The article describes the influence of chrysotile nanofibers dispersion introduction on the properties of the cement matrix. Comparison of the dispersion level of suspensions obtained using cavitation and ultrasonic processing methods is presented. The positive effect of chrysotile fibers application on the strength characteristics of the material has been confirmed. A 34% increase in the compressive strength of the samples was achieved on the 7th day of hardening, while on the 28th day it increased by 36% and with the steam treatment - by 38% compared to the reference sample. Laser particle size analysis confirmed the predominance of the nanosized component of chrysotile fibers in the suspension, which affected the structuring of the cement matrix. The results of the differential thermography, IR spectrometry, X-ray microanalysis and scanning electron microscopy of the samples are also presented. The analysis methods confirmed that introduction of chrysotile nanofibers suspension into the composition of a cement binder makes it possible to significantly vary the structure and morphology of new formations in fine-grained concrete. It also changes the quantitative and qualitative phase composition of the material with the formation of calcium silicate hydrates of lower basicity, leading to an increase in the strength of cement concrete.

We reported the use of an inverse vulcanised polysulfide (SP) as an intelligent interfacial modifier in the NR/CB composites to remarkably decrease the hysteresis loss by enhancing the interfacial adhesion and improving CB dispersion. Specifically, SP synthesized by the bulk copolymerization of sulfur and styrene was grafted onto CB surface by trapping the sulfur radicals generated from SP, and the grafted polysulfides can participate in the crosslinking reaction with NR, which greatly improves CB dispersion and strengthens interfacial adhesion in the composites. As a consequence, the rolling resistance and heat build-up of the modified composites are remarkably decreased, showing great advantages in tire application in term of reducing fuel consumption and extending service life.

Liquid droplets in solid soft composites have been attracting increasing attention in biological applications. In contrary with conventional composites, which are made of solid elastic inclusions, available material models for composites including liquid droplets are for highly idealized configurations and do not include all material real parameters. They are also all deterministic and do not address the uncertainties arising from droplet radius, volume fraction, dispersion and agglomeration. This research revisits the available models for liquid droplets in solid soft composites and presents a multiscale computational material model to determine their elastic moduli, considering nearly all relevant uncertainties and heterogeneities at different length scales. The effects of surface tension at droplets interface, their volume fraction, size, size polydispersity and agglomeration on elastic modulus, are considered. Different micromechanical material models are incorporated into the presented computational framework. The results clearly indicate both softening and stiffening effects of liquid droplets and show that the model can precisely predict the effective properties of liquid droplets in solid soft composites.

The ultrafine Mo-Y2O3 composite powders were successfully synthesized by innovative freeze-drying method. Consequently, the freeze-dried Mo-Y2O3 composite powders with high sintering activities possess an average grain size of 54 nm. After low temperature sintering at 1600 °C, the Mo-Y2O3 alloys maintaining a high density (99.6 %) have the finest grain size (620 nm) comparing with available literature about oxide dispersion strengthened molybdenum alloy (ODS-Mo). The oxide particles remain their small size (mainly

The effect of distributor geometry on bubble characteristics in an air–kerosene system of a pressurized bubble column was evaluated. The experiment was carried out using a cylindrical stainless column with an inner diameter of 0.097 m and a height of 1.8 m under a system pressure up to 3.5 MPa. The gas holdup was calculated under pressure taps from 0.05 m to 0.85 m above the distributor along axial direction of the column. Bubble size was measured with an optical probe installed 0.5 m above the distributor. Perforated plates with four different hole sizes including 0.8 mm (20 each), 1 mm (12 each), 2 mm (3 each), and 3.46 mm (1 each) fixed with the same opening fraction (ϕo = 0.128%) were evaluated. Different opening fractions at 0.223% (21 holes), 0.128% (12 holes), 0.074% (7 holes), and 0.032% (3 holes) were also tested with a constant hole size (1 mm). The effect of the distributor geometry on bubble characteristics was determined with seven different types of perforated plates. The number of microbubbles was increased with decreasing opening fraction of the distributor. Based on dynamic gas disengagement (DGD) analysis, microbubbles were rarely generated in all distributors under conditions of Psys = 0.1 MPa at Ug = 12.3 mm/s. However, a significant number of microbubbles were generated at ϕo = 0.032% despite a low flow rate at Psys = 3.5 MPa. Microbubble ratio varied from 36% to 40% at ϕo = 0.128 %, while this ratio varied from 38% to 73% at ϕo = 0.032%.

At present, more and more flexible pressure sensors are used in wearable devices. The improvement of the adsorbability of nanomaterials on sponge flexible pressure sensors is an urgent problem to be solved. Here, using conductive carbon black with good dispersibility and small particle size as the conductive filler filled in the middle of the sponge can improve the absorbability of the sponge. A simple method of soaking a sponge with different thicknesses in conductive carbon black dispersion is used to obtain flexible pressure sensors based on conductive carbon black/sponge. We compare and analyze the differences in initial resistance and sensitivity of sponge pressure sensors with different thicknesses and select the sensor with higher sensitivity (0.194 kPa−1) for response time, recovery time, and stability tests. The sensor is used in the neck, wrist, knee, and other body parts for motion recognition. The two conductive carbon black/sponge sensors are placed orthogonally on the back to identify nod, tilt head, and placed on the elbow to test the angle of arm bending. Conductive carbon black/sponge flexible pressure sensor shows good application prospects in the wearable field.

Oxide-dispersion-strengthened (ODS) steels are promising material candidates for nuclear fission and fusion applications. Nanosized oxide particles in as-rolled ODS steel PM2000 were investigated b...

Актуальною задачею сьогодення є вдосконалення установок для екструзії термоластів, з метою підвищення показників ресурсоенергоефективності. Дослідження особливостей завантажувально-пластикувальної зони (ЗПЗ) і ліквідація недоліків дозволяє значно знизити енерговитрати процесу. Для досягнення якісних результатів при каскадній дисково-шестеренній екструзії проаналізовано головні методи процесу дисперсійного плавлення гранул термопласту, враховуючи всі особливості фізичної моделі процесу екструзії. Дисперсійна модель плавлення досягається шляхом дотримання обмеженої подачі сировини в завантажувальну зону. Це забезпечує інтенсифікацію процесу і значно зменшує значення загальної довжини ЗПЗ. При цьому довжина ділянки з максимально заповненим каналом напряму залежить від опору дискової зони. Із зростанням опору полімерна пробка переміщується до завантажувальної горловини. Полімер поступово ущільнюється, а кожен виток ЗПЗ періодично заповнюється. З розігрітого до 107С диску, що обертається, знімались і розрізались на окремі ділянки зразки полімеру. Попередньо для полегшення процесу візуального дослідження, полімер був забарвлений 0,5% блакитним пігментом. Результати аналізу підтвердили працездатність пропонованої фізичної моделі процесів, що протікають в ЗПЗ дискового екструдера. Внаслідок цього з’являється можливість розрахувати час перебування гранули в ЗПЗ і довжину гвинтової нарізки в цій зоні в залежності від продуктивності. Врахування всіх особливостей процесу дисково-шестеренної екструзії дозволяє створити модернізовану продуктивну, ресурсоефективну установку і реалізувати її на практиці. The relevant task of today is to improve the installations for thermostat extrusion, in order to increase the indicators of resource/energy efficiency. The study of the features peculiar to the loading and melting area (LMA) and the elimination of shortcomings can significantly reduce the energy costs of the process. To achieve high-quality results in cascading disk-gear extrusion, the main methods of the dispersion melting of thermoplastic granules are analyzed, taking into account all the features of the physical model of the extrusion process. The dispersion model of melting is achieved by observing a limited supply of raw materials to the loading area. This ensures the intensification of the process and significantly reduces the total length of the LMA. In this case, the length of the area with the most filled channel directly depends on the resistance of the disk zone. With increasing resistance, the polymer stopper moves to the loading neck. The polymer is gradually compacted, and each leakage of the LMA is periodically filled. From the rotating disk heated to 107 oC, samples of the polymer were removed and cut into separate sections. Previously, to facilitate the process of visual research, the polymer was colored with 0.5% blue pigment. The results of the analysis confirmed the performance of the proposed physical model for the processes occuring in the disk-gear extruder. As a result, it is possible to calculate the time over which the granules stay in the LMA and the length of the screw cutting in this area, depending on the performance. Taking into account all the features of the disk-gear extrusion process allows creating an upgraded productive, resource-efficient installation and implementing it into practice.

The nonisothermal melt crystallization behavior of fully biodegradable poly(ethylene succinate)/cellulose nanocrystals (PES/CNC) composites with low loadings of CNC from 0.25 to 1 wt% was studied in detail in this research at different cooling rates with differential scanning calorimetry. As an efficient heterogeneous nucleating agent, CNC remarkably enhanced the melt crystallization of PES, thereby obviously increasing the crystallization rate coefficient parameters of the composites. The Ozawa method failed to analyze the melt crystallization kinetics of both neat PES and its composites. Through the methods proposed by Dobreva and Ortega, the nucleation activity of CNC and crystallization activation energy of the composites were calculated, respectively, showing the CNC loading dependence. When CNC loading was 0.5 wt%, the composite showed the highest melt crystallization peak temperature at the same cooling rate, greatest crystallization rate coefficient, strongest nucleation activity, and highest absolute crystallization activation energy at the same extent of conversion. The nucleation mechanism of PES on CNC surface was proposed; moreover, the CNC loading dependence of the crystallization of PES was further discussed through the dispersion of CNC in PES matrix study.