Subsequent Extrusion Research Articles

Computation‐Guided Scope Exploration of a Conjugate Addition/Truce‐Smiles Cascade Reaction for Scaffold Diversification

AbstractBased on the successful application of a nitroaryl transfer cascade reaction in the total synthesis of various monoterpene indole alkaloids proceeding via fused bicyclic intermediate, we investigated analogous cascade reactions involving spiro, bridged, and alternatively fused bicyclic intermediates. Unfortunately, none of these was found to afford the desired nitroaryl transfer product. DFT studies of the original cascade process revealed that the Truce‐Smiles rearrangement is the rate‐determining step. In addition, we found that the subsequent SO2 extrusion is accompanied by retro‐Mannich ring opening, resulting in a stabilized enolate that only recyclizes after activation of the cyclic imine moiety. Computation of the reaction profiles of the proposed alternative cascade reactions showed that the barrier for the Truce‐Smiles rearrangement is unreasonably high for the bridged and alternatively fused systems, but only moderately higher for the five‐membered spiro system. Reasoning that even more electron‐deficient arenesulfonamides should have a lower barrier for the Truce‐Smiles rearrangement, we synthesized the corresponding 2,4‐dinitrobenzenesulfonamide precursor and found that it indeed smoothly undergoes the nitroaryl transfer cascade at room temperature. In this case, however, the cascade reaction produces a cyclic imine product, as the intermediate 2,4‐dinitrophenyl‐substituted enolate is insufficiently nucleophilic to undergo the Mannich cyclization.

In-situ synthesis and microstructural evolution of a SiC reinforced Al-50Si composite exhibiting exceptional thermal properties

Incorporating carbon nanotubes (CNTs) into Al-Si alloy to prepare in-situ SiC/Al-Si composites enhances thermal conductivity (TC) and reduces the coefficient of thermal expansion (CTE). However, challenges include CNTs aggregation and uneven SiC distribution. This study uses fluidized bed chemical vapor deposition (FBCVD) to achieve uniform CNTs coverage on Al-50Si powder. Subsequent powder hot extrusion and heat treatment above the eutectic temperature enable a gradual reaction between CNTs and Al/Si atoms, resulting in uniformly dispersed SiC within the SiC/Al-50Si composite. The formation mechanism of in-situ SiC particles and their impact on the microstructure, thermal and mechanical properties of the composite are further investigated. The formation process involves a two-step chemical reaction: lamellar Al4C3 phases transform into lamellar eutectic SiC + Al phases, which then transition into polyhedral SiC particles through epitaxial growth. This in-situ formation of SiC particles also impedes Si growth during heat treatment, refining Si particles and enhancing the composite’s properties. The resulting in-situ SiC/Al-50Si composite exhibits excellent thermal and mechanical properties, including a high TC of ∼162 Wm-1K−1, a low CTE of ∼ 8.7 × 10-6/K, and a good bending strength of approximately 253 MPa at room temperature.

Переходные участки бесстыкового пути, примыкающие к стрелочным переводам

Purpose: consider the problem of interaction between turnouts and adjacent sections of a seamless railway track. Methods: statistical data analysis. Results: an analysis of the results of domestic and foreign studies has been carried out, which show that in such areas there is a jump with subsequent extrusion of material of less rigidity and an increase in the slope of the elastic unevenness, i. e., an undesirable phenomenon occurs — a shock wave. The impact force depends on the mass of the rolling stock and the speed of movement, the geometric evenness of the rail track and the chosen approaches to designing the transition zone as a whole. Jump and mainly occurs due to compression and pushing out of structural layers and materials of lower rigidity in the under-rail area. The impact force depends on the mass of the rolling stock and the speed of movement, the geometric evenness of the rail track and the chosen approaches to designing the transition zone as a whole. Jump and mainly occurs due to compression and pushing out of structural layers and materials of lower rigidity in the under-rail area. Shock waves caused by uneven rigidity of sections have negative consequences (the appearance of deviations in level, subsidence, distortions, increased intensity of rail wear, the appearance of rail defects), which increase the cost of maintenance of the railway track. An analysis of the accumulation of residual deformations has been carried out, which shows the systematic formation of geometric irregularities in adjacent areas in the turnout area. Practical importance: from the point of view of the design of the transition zone, the expected advantage will be the differentiation of structural materials and elements and their influence on achieving the optimal gradation of railway track rigidity in the vertical and horizontal (transverse, longitudinal directions), selection of the optimal ratio of the mechanical properties of individual elements of the superstructure structure. It should also be noted that it is necessary to conduct an additional feasibility study of the feasibility of constructing transition sections in the area where the track and switches meet, taking into account the operational features of individual railway lines.

Improving the shape and dimensional accuracy of hollow semi-finished products during hot reverse extrusion from square workpieces

Stamping of round hollow semi-finished products by hot reverse extrusion from round and square workpieces is the first stamping step in the manufacture of hollow products for special purposes. These products require certain mechanical properties along the wall height and in the bottom part, which can be achieved by working out the metal structure by plastic deformation. The bottom part is worked out by reverse extrusion. The wall properties are obtained in the following stages of drawing the semi-finished product with thinning after extrusion. The use of square workpieces results in more intensive working out of the bottom of the semi-finished products during the reverse extrusion. However, as a result of extrusion, four protrusions appear at the end of the semi-finished product wall in places that match the corner areas of the workpiece. The presence of protrusions leads to the need for an additional operation of cutting the end of the semi-finished product before extrusion, as well as to an increase in metal usage. Therefore, an urgent task is to study the method of eliminating protrusions in the semi-finished product and the additional cutting operation.To improve the accuracy of the shape and size of hollow semi-finished products during hot reverse extrusion from square workpieces.Elimination of protrusions is achieved by forming chamfers in the corner zones of the square workpiece by preliminary deposition before extrusion.The finite element method (FEM) was used to model the processes of hot deposition of corner zones on a square workpiece and subsequent reverse extrusion with the dispensing of round hollow semi-finished products. The dimensions of the chamfers on the high-carbon steel workpiece were determined, which ensured the elimination of protrusions at the end of the wall of the round semi-finished product after extrusion. The dependence of the deposition and extrusion forces on the punch movement was determined. The specific forces on the deforming tool were determined. The distributions of stresses, strains, and temperature in the deformed metal at the end of deposition and extrusion are presented. The working out of the metal structure by hot plastic deformation is evaluated. The design of a stamp for deposition and extrusion is developed.The geometry of a square workpiece with chamfers in the corner zones was determined, which ensures the elimination of protrusions at the wall end during hot reverse extrusion with the dispensing of round hollow semi-finished products

Achieving superior strength and ductility synergy in bulk ultrafine grained Al-Mg-Sc-Zr alloy via powder pre-aging

Introducing high density of nano-precipitates to recrystallized ultrafine grains is helpful to realize strength-ductility synergy but is a challenging task, because recrystallization and precipitate growth/coarsening usually concur. Here we develop a pre-aging powder metallurgy processing route to achieve such microstructure in Al-Mg-Sc-Zr alloy. During the pre-aging stage, atomic clusters including short-range order are formed within the grains, which provide new sites for the nucleation and enable the formation of fine Al3(Sc, Zr) precipitates. Subsequent high-temperature sintering and hot extrusion lead to grain recrystallization. The nano-precipitates not only further strengthen the ultrafine-grained alloy by Orowan mechanism, but also greatly enhance the strain-hardening rate by dislocation-precipitate interaction, resulting in excellent strength-ductility synergy. The utilization of digital image correlation (DIC) analysis allows for the observation of dynamic strain aging during the tensile process, whereby the strain demonstrates a distinctive step-like transition coinciding with the passage of the Portevin-Le Chatelier (PLC) band. This work provides a new path for improving the mechanical properties of the same type of metallic materials.

Engineering of exosome-liposome hybrid-based theranostic nanomedicines for NIR-II fluorescence imaging-guided and targeted NIR-II photothermal therapy of subcutaneous glioblastoma

Exosome-liposome hybrid-based vehicles (ELV) are promising carriers for cancer treatment, but there are rare efficient theranostic probes to label their lipid bilayer membrane for precisely tracing biodistribution and execute potent therapy. As both fluorescence imaging and photothermal therapy in the second near-infrared window (NIR-II) has intrinsically deep penetration and high efficacy to ablate tumors, herein the design and synthesis of lipophilic NIR-II cyanine dyes with strong donor strength is reported to label lipid bilayer membrane of ELV for NIR-II fluorescence image-guided and targeted NIR-II photothermal treatment of subcutaneous glioblastoma. Via lipid film hydration and subsequent extrusion method, the synthesized ELV (NIR-C12-EL) is formulated with NIR-C12 labeling, cyclic arginylglycylaspartic acid decoration, liposomal PEGylation, and biological exosome function. NIR-C12-EL exhibits excellent colloidal stability, good biocompatibility, strong light harvesting capability, high NIR-II photoconversion efficiency (62.28 %), and targeting capability to diagnose and ablate tumors, which together contribute to the extended life-span of the mice treatment with NIR-C12-EL and continuous 1064 nm laser irradiation. This study provides insight into not only designing of lipophilic NIR-II fluorescence probes for labeling of exosome-liposome hybrid-based vehicles but also the engineering of theranostic nanoplatforms for precise treatment of glioblastoma.

The role of calcium addition through powder sintering process in microstructure and mechanical behavior of a microalloyed magnesium

Calcium effectively strengthens magnesium through grain refinement when added in small quantities using the ingot metallurgy process. The extremely low solubility of calcium in magnesium restricts its addition using traditional powder metallurgy processes. However, the powder metallurgy process provides advantages like reduced material loss, properties control, and net-shape products. Hence, in this study, a diluted magnesium-calcium alloy was processed using the traditional blend-press-sinter (BPS) powder metallurgy process. Commercially pure magnesium was microalloyed with 0.4 wt% calcium. The sintered magnesium-calcium alloy was subjected to high-temperature extrusion. Microstructural characterization of the microalloyed Mg0.4Ca alloy revealed that the elemental calcium diffused into the magnesium particles during the sintering process and developed a gradient granular microstructure. The added initial calcium nanoparticles also acted as nucleation sites for magnesium during the sintering process. The gradient microstructure recrystallized and grew into equiaxed grains during the subsequent extrusion process. Mechanical properties characterization revealed that the addition of calcium as solute atoms increased the hardness, compressive strength, and ductility of magnesium, which was further enhanced by the extrusion process. The presence of calcium as solute atoms increased the tensile strength of extruded magnesium by a reasonable amount, while ductility remained almost unchanged.

Activation mechanisms of dimeric mechanosensitive OSCA/TMEM63 channels

OSCA/TMEM63 channels, which have transporter-like architectures, are bona fide mechanosensitive (MS) ion channels that sense high-threshold mechanical forces in eukaryotic cells. The activation mechanism of these transporter-like channels is not fully understood. Here we report cryo-EM structures of a dimeric OSCA/TMEM63 pore mutant OSCA1.1-F516A with a sequentially extracellular dilated pore in a detergent environment. These structures suggest that the extracellular pore sequential dilation resembles a flower blooming and couples to a sequential contraction of each monomer subunit towards the dimer interface and subsequent extrusion of the dimer interface lipids. Interestingly, while OSCA1.1-F516A remains non-conducting in the native lipid environment, it can be directly activated by lyso-phosphatidylcholine (Lyso-PC) with reduced single-channel conductance. Structural analysis of OSCA1.1-F516A in lyso-PC-free and lyso-PC-containing lipid nanodiscs indicates that lyso-PC induces intracellular pore dilation by attracting the M6b to upward movement away from the intracellular side thus extending the intracellular pore. Further functional studies indicate that full activation of MS OSCA/TMEM63 dimeric channels by high-threshold mechanical force also involves the opening of both intercellular and extracellular pores. Our results provide the fundamental activation paradigm of the unique transporter-like MS OSCA/TMEM63 channels, which is likely applicable to functional branches of the TMEM63/TMEM16/TMC superfamilies.

Ingredient Functionality of Soy, Chickpea, and Pea Protein before and after Dry Heat Pretreatment and Low Moisture Extrusion.

This study investigates the impact of dry heat pretreatment on the functionality of soy, chickpea, and pea protein ingredients for use in texturized vegetable protein (TVP) production via low moisture extrusion. The protein powders were heat-treated at temperatures ranging from 80 °C to 160 °C to modulate the extent of protein denaturation and assess their effects on RVA pasting behavior, water absorption capacity (WAC), and color attributes. The results indicate that the pretreatment temperature significantly influenced the proteins' functional properties, with an optimal temperature of 120 °C enhancing pasting properties and maintaining WAC, while a higher pretreatment temperature of 160 °C led to diminished ingredient functionality. Different protein sources exhibited distinct responses to heat pretreatment. The subsequent extrusion processing revealed significant changes in extrudate density and color, with increased density and darkness observed at higher pretreatment temperatures. This research provides insights into the interplay between protein sources, pretreatment conditions, and extrusion outcomes, highlighting the importance of controlled protein denaturation for developing high-quality, plant-based meat analogues. The findings have broad implications for the optimization of meat analogue manufacturing, with the aim of enhancing the sensory experience and sustainability of plant-based foods.

Effects of homogenization temperature on microstructure, mechanical properties and corrosion behavior of binary Zn-Mn alloys extruded at different temperatures

In order to optimize the mechanical properties (MPs) of biodegradable Zn-based alloys, many researches have been conducted. However, the effect of homogenization treatment before the plastic deformation process on the MPs of biodegradable Zn-based alloys has not received sufficient attention, although it has been demonstrated to play an important role in improving the MPs of Al- and Mg-based alloys. In this work, as-cast Zn-0.8 wt% Mn alloys were firstly homogenized at two different temperatures (330 and 390 °C) followed by quenching and then extruded at three different temperatures (170, 230 and 300 °C). This work revealed the effects of homogenization temperature (HT) on microstructure, MPs and corrosion behavior of Zn-0.8 wt% Mn alloys extruded at different temperatures. The results showed that compared to the alloy homogenized at 330 °C (HT330), the alloy homogenized at 390 °C (HT390) has less precipitation of micron-sized MnZn13 particles in the homogenization process. During the subsequent extrusion processes at 170 and 230 °C, more submicron-sized MnZn13 particles are precipitated and finer Zn grains are formed in the HT390 alloys than in the HT330 alloys. Correspondingly, the two extruded HT390 alloys exhibit elongations of up to 133 % and 86 %, respectively, which are much higher than the 71 % and 65 % of the two extruded HT330 alloys. However, when the extruding temperature is elevated to 300 °C, high HT causes decrease in the fraction of both the micron- and submicron-sized MnZn13 particles as well as coarsening of Zn grains, followed by an increase in the strength of the as-extruded alloy. In addition, high HT is conductive to improving the corrosion resistance of the as-extruded alloys regardless of the extrusion temperature.

Transformation of the diamond surface with a thin iron coating during annealing and transport properties of the formed conductive layer

In our study, we annealed polycrystalline diamond films with nanometer-thick iron coatings. Based on analysis of X-ray photoelectron spectroscopy data the presence of two catalytic processes was suggested. One is the continuous absorption of sp3 carbon by iron nanoparticles with subsequent extrusion of the sp2 phase from the formed iron carbide, which leads to the creation of deep tracks into the diamond bulk that are filled with graphite stacks. The other process involves a thin layer of iron carbide on the surface and results in the creation of sp2 layers, which are made up of fused graphene-like patches and are oriented mainly along the surface of the diamond film. For the sample annealed at 800 °C for 1 h, the sp2 layers formed exhibit semi-metallic conductivity with quantum corrections caused by disorders. At the same time, no evidence of iron contribution in conductivity of the annealed Fe-coated film was detected, implying that upon transforming the diamond, iron moved quite deep into the bulk. In addition, the formed conductive layer on the diamond surface shows mechanical stability, ensuring the reproducibility of conductivity measurements even after six months of storage in air. The study has revealed the potential for targeted metal-assisted formation of sp2 carbon-based conducting pathways on diamond surfaces for electronic devices.

Investigation of neutering status and age of neutering in female Dachshunds with thoracolumbar intervertebral disc extrusion.

To evaluate neutering status and age of neutering in female Dachshunds with thoracolumbar intervertebral disc extrusion. We hypothesised that neutered Dachshunds presented with intervertebral disc extrusion at an earlier age, with a higher grade of neurological deficits and with more extensive extrusion of disc material compared with intact females. Retrospective multi-centre study of client-owned female Dachshunds with surgically confirmed thoracolumbar intervertebral disc extrusion. Dogs were classified as early, late or not neutered (intact). Age, body condition score, duration of clinical signs before presentation, modified Frankel score at presentation, length of extruded disc material, maximum spinal cord compression and whether dogs presented for a subsequent intervertebral disc extrusion were recorded. One hundred and fifty-four dogs were included: 36 early neutered, 69 late neutered and 49 intact. No significant difference was found between early neutered, late neutered and entire female Dachshunds in any of the variables studied. In this cohort of female dogs, neuter status and age of neutering were not found to affect age at onset nor severity of thoracolumbar intervertebral disc extrusion.

Simultaneous enhancement in mechanical and physical properties of graphene-oxide-reinforced Al matrix composites by trace-Mg-alloying strategy

This paper proposes a trace-Mg-alloying strategy to fabricate high-performance graphene oxide (GO)-reinforced Al metal matrix composites (MMC). A minute quantity (0.4 wt%) of elemental Mg was introduced in Al–Si alloy powders. Individual GO nanosheets were uniformly decorated onto the surface of the AlSiMg particle through electrostatic attractions via hetero-agglomeration. A GO network was formed at the primary boundaries of AlSiMg particles through spark plasma sintering of GO/AlSiMg mixed powders. In this process, elemental Mg reacted with the oxygen atoms within GO nanosheets, resulting in the in situ production of high-quality reduced GO. Subsequent hot extrusion disrupted the GO network owing to the metal plastic flow, causing the GO nanosheets to realign in a single direction. Consequently, the tribological behavior, tensile response, and thermal and electrical conductivities of the GO/AlSiMg composites were simultaneously enhanced. Hot extrusion led to stretching of the overlapping GO nanosheets and increased surface contact area of AlSiMg powders. Thus, the extruded samples exhibited peak electrical conductivity at 0.2 wt% GO, whereas the sintered samples demonstrated peak thermal conductivity at 0.1 wt% GO. Overall, the findings of this study highlight the potential of merging trace powder alloying and powder metallurgy techniques to create multifunctional nanocarbon/MMCs without a trade-off between mechanical and physical performance.

Challenges in block-and-ash flow hazard assessment: The July 10–11, 2015 eruption of Volcán de Colima, Mexico

On July 10 and 11, 2015, Volcán de Colima, one of the most active Mexican volcanoes, underwent its largest eruption since the 1913 Plinian event. Highly mobile block-and-ash flows (BAF) originated from the dome collapse and subsequent extrusion of bubble gas-rich magma from the conduit. The volume and runout of flows were at least one order of magnitude higher (106 m3) than the events observed previously in the 2004–2005 eruptive episode (105 m3) and only comparable with the pyroclastic density currents emplaced during the Vulcanian eruptive phase that preceded the 1913 Plinian eruption. The TITAN2D code is here used to understand the factors controlling the mobility of the dense BAF undercurrents emplaced during the 2015 eruption. The selection of different input parameters was based on field data, on the seismic signal of the BAFs recorded by a broadband station located a few meters away from the channel, and by considering the different eruptive mechanisms of the July 10 eruptive phase (collapsing dome) with respect to the July 11 event (rapid extrusion of degassed magma directly from the conduit). A collapsing pile best fits the July 10 BAF, with an initial spread on the proximal reach and subsequent emplacement along the Montegrande ravine. Instead, for the July 11 BAF, an influx source best replicates the observed distribution, including the overspilling down the San Antonio ravine at the middle reach and the aggradation at the final depositional fan. Both events were better reproduced with the Voellmy-Salm rheology with respect to the Mohr-Coulomb model. Still, the mobility of the July 11 BAF was controlled mainly by the channel reduced capacity due to the 10 July BAF infilling. This was assessed by modeling the 11 July BAF on the real terrain and on a DEM whose altitude was modified based on the maximum flow depth obtained from the simulation of the former flow. Deep knowledge of the eruptive mechanism and flow behavior during the 2015 eruption allowed us to understand the main factors controlling concentrated pyroclastic density current mobility during sustained, multi-phase eruptions, especially for valley-confined BAF. The results presented here set the basis to improve the hazard zonation for pyroclastic density currents at Volcán de Colima, which should be based on a multifactor, probabilistic analysis.

Near-room-temperature water-mediated densification of bulk van der Waals materials from their nanosheets.

The conventional fabrication of bulk van der Waals (vdW) materials requires a temperature above 1,000 °C to sinter from the corresponding particulates. Here we report the near-room-temperature densification (for example, ∼45 °C for 10 min) of two-dimensional nanosheets to form strong bulk materials with a porosity of <0.1%, which are mechanically stronger than the conventionally made ones. The mechanistic study shows that the water-mediated activation of van der Waals interactions accounts for the strong and dense bulk materials. Initially, water adsorbed on two-dimensional nanosheets lubricates and promotes alignment. The subsequent extrusion closes the gaps between the aligned nanosheets and densifies them into strong bulk materials. Water extrusion also generates stresses that increase with moulding temperature, and too high a temperature causes intersheet misalignment; therefore, a near-room-temperature moulding process is favoured. This technique provides an energy-efficient alternative to design a wide range of dense bulk van der Waals materials with tailored compositions and properties.

Combining two relatively weak bases (Zn(TMP)2 and KOtBu) for the regioselective metalation of non-activated arenes and heteroarenes.

Co-operation between two relatively weak Brønsted bases, Zn(TMP)2 and KOtBu, produces a bimetallic base strong enough to regioselectively zincate non-activated arenes such as naphthalene, biphenylene and anthracene under mild conditions. This co-operativity is also effective with a range of more sensitive five-membered ring heterocyclic substrates including benzoxazole and caffeine. Metalation products have been intercepted with iodine, affording the relevant iodo-(hetero)arenes in good to excellent yields with finely tuned regioselective control. Combining NMR spectroscopic and X-ray crystallographic studies has uncovered that depending on the solvent, a complicated ligand distribution process of mixed aryl/alkoxy higher order zincate intermediates, (THF) n K2Zn(Ar)2(OtBu)2, that can liberate lower order zincates of the form [(THF)2KZn(Ar)(OtBu)2]2 and eliminate potassium aryl species. While this ligand redistribution process seems to operate for non-substituted (hetero)arene metalation products, for non-activated alkylarenes such as mesitylene or m-xylene the higher-order zincates resulting from their lateral metalation are stable in solution and the solid state, which is attributed to the greater π-stabilisation that these systems can provide to the K cations. Adding another layer of complexity to this heterobimetallic system, over time the Zn(TMP)2/2KOtBu combination reacts with the THF solvent of these reactions, to afford an unusual decomposition product which contains an s-trans-1,3-butadienyl (C4H5 -) fragment coordinated to Zn within a potassium zincate structure. The formation of the latter is attributed to the initial synergistic α-zincation of THF, followed by subsequent ring opening and oxygen extrusion.

Straightforward Design Strategy toward 3D Near-Net-Shape Stoichiometric SiC Parts.

Fused deposition modeling (FDM), traditionally reserved for thermoplastics, is modified here with a granule-based extrusion head to be extended to advanced nonoxide ceramics via a straightforward design strategy that considers the shaping opportunities and the chemical richness offered by preceramic polymers. Specifically, 3D near-net-shape stoichiometric silicon carbide (SiC) objects are designed by manipulating the key features of a commercially available polycarbosilane (fusibility, high carbon content, relatively high SiC yield). In the early stage of the process, the carbon-rich polycarbosilane is first mixed with Si and SiC fillers and then thermolyzed at 120 °C to increase polymer branching while offering tailored rheological properties during the subsequent extrusion process at 90 °C and adequate shape retention once extruded. This allows for the design of tailored and complex 3D complex polycarbosilane-based architectures with features down to 400µm. Polymer-based parts are further converted into 3D stoichiometric SiC objects with quasi-near-net-shape-a volume shrinkage reduced to 9.1% is measured-by heat treatment at a temperature as low as 1400 °C (argon flow). Given the flexibility to tune the preceramic polymer chemical and rheological properties, a new combined design approach is leveraged to generate bespoke advanced ceramics with a high freedom in geometry complexity.

Study of Polymer Matrices Based on Blends of Polyvinyl Chloride and Grafted Copolymers

The development of mixed matrices is a well-established and suitable method for obtaining new polymeric materials. The combination of two different types of polymers allows you to get a new and unique material that has the properties of both polymers. This paper compares polymer matrices based on polyvinyl chloride (PVC) and various graft copolymers in order to select the optimal compositions for further filling. Domestic acrylonitrile butadiene styrene (ABS) and imported acrylonitrile styrene acrylate (ASA) were chosen as graft copolymers. Despite the manufacturability of copolymers, the subsequent extrusion of filled compositions is more appropriate with a PVC/ABS matrix, since power consumption during processing will be reduced. At the same time, the matrix based on a mixture of PVC/ASA polymers has higher strength properties, but PVC/ABS has the best effect as an impact-resistant matrix. Depending on the content of the copolymer, the structure of compositions based on polymer mixtures can be microdispersed or viscous and layered, which will determine the main physical and mechanical properties. In general, both matrices can be used for further filling, but with a copolymer content of less than 50 phr.

Optimization of the Extrusion Process in the Production of Compound Feeds for Dairy Cows

The paper proposes a way of enriching the composition of mixed fodder by combining two promising technologies with known effects: inclusion of germinated grain in the composition and extrusion. Crude and digestible protein, fiber, fat, and mineral elements Ca, K, Na, and P were studied. Inclusion of sprouted grain into mixed fodder and subsequent extrusion contribute to improvements in taste qualities, increased edibility, and assimilation of mixed fodder, as well as nutritive value. Taking into account the obtained knowledge about the influence of temperature regime and content of germinated triticale grain in mixed fodder production, it is advisable to continue research to adapt the technology and develop formulations for different types of animals and farm birds. The purpose of the study was to optimize the process of extrusion of sprouted triticale grain in order to reduce energy consumption and obtain high-quality extrudates. To achieve this goal, the following tasks were set: to analyze the regime factors affecting the fat content based on the optimization of technological modes of extrusion. To optimize the technology of extrusion of triticale grain of the Kozha variety, the fat content was chosen as the target function. Optimization of the technology of extrusion of triticale grain of the Kozha variety was carried out by the method of nonlinear programming. The following optimal technological modes of grain extrusion were obtained: The content of sprouted triticale grain is 15%, and the extrusion temperature is 140°C. With these optimal grain processing modes, the target function was 1.12%. The practical significance of the technology of the production of compound feeds with the use of extrusion in order to improve the quality and increase the shelf life. Doi: 10.28991/ESJ-2023-07-05-08 Full Text: PDF

Optimization in strength-ductility of Mg-Gd-Y-Zn-Zr alloy processed by upsetting-extrusion combined with intermediate thermo-mechanical treatment (ITMT)

In this work, the effects of intermediate annealing and intermediate annealing subsequent aging treatment on the second phase precipitation, dynamic recrystallization (DRX) behavior, and mechanical properties of Mg-9Gd-4Y–2Zn-0.5Zr (wt.%) alloy were comparatively studied. The results showed that the one-pass upsetting-extrusion (UE) deformation intermediate annealing treatment sample (UAE) exhibited the highest dynamic recrystallized (DRXed) grains number fraction and the largest average DRXed grain size, which was mainly attributed to the precipitation of a large number of β-Mg5RE phases (>1 μm) at the grain boundaries (GBs) and within unDRXed grains after annealing treatment. These β-Mg5RE phases promoted DRX through particle-stimulated nucleation (PSN) mechanism during subsequent extrusion process. However, the lack of the pinning effect of the fine second phase precipitations led to the growth of DRXed grains. The DRXed grains of the deformation intermediate annealing subsequent peak-aging treatment sample (UAAE) were significantly smaller than the UAE sample. This is mainly due to the fact that the densely distributed prismatic β′ phases precipitated by the peak-aging treatment were rapidly transformed into nano-scale β-Mg5RE phases and pinned at the DRXed grain boundaries to inhibit the growth of the DRXed grains during the subsequent extrusion process. The ultimate tensile strength (UTS) and failure elongation (EL) of the UAAE sample were 274 MPa and 14.3%, respectively, 4.2% and 85.7% higher than those of the UE sample, showing excellent strength-ductility synergy. The randomly oriented fine DRXed grains, coarse unDRXed grains with high-density dislocations and substructures, and nano-scale β-Mg5RE particles were co-contribute to the strength-ductility synergy.