Crosslinking, Mechanical Properties, and Antimicrobial Activity of Photocurable Diacrylate Urethane/ZnO-Ag Nanocomposite Coating

In this article, ZnO-Ag nanohybrids were chemically synthesized in the aqueous medium by reducing silver nitrate with sodium borohydride NaBH4. These nanohybrids were then homogeneously dispersed into the diacrylate urethane/1,6-hexanediol diacrylate resin system at a content of 2 wt%. The structural morphology, mechanical resistances, and crosslinking of the as-prepared nanocomposite coating (nanocoating) were evaluated. The antimicrobial characteristic was tested by keeping track of the lag-log growth phase of E. coli bacteria in the coating existence among cell cultures. The obtained data indicated that the nanohybrids added into the UV curing diacrylate urethane matrices had significantly increased the abrasion resistance, relative hardness, and conversion of the acrylate groups of the nanocoating. In addition, the antibacterial test revealed that the nanocoating had good antibacterial property against E. coli, whereas for the pure coating (without ZnO-Ag nanoparticles), there was no antibacterial activity observed.

Hybrid Metallic Coatings on Polymer-Based Composites

A previous study showed that Cu can be cold sprayed onto carbon fiber-reinforced polymers (CFRPs) if a Cu interlayer is deposited prior to low-pressure cold spraying. In this present study, Cu was cold sprayed onto CFRP substrates that were coated with either Sn (cold spray) or Ni electroplating. Two layers of Cu powder were also cold sprayed onto a Cu-plated CFRP substrate to investigate the effect of a second particle layer on impacting particles. Test results showed that the relative hardness between the particle and substrate has a major effect on deformability, impact mode, and deposition efficiency (DE), which explains why Cu could not be cold sprayed onto Sn or Ni interlayers and why the deposition efficiency of Cu-on-Cu substrates is lower than that of one pass spraying. In summary, the results suggest that Cu can be successfully cold sprayed at low pressures onto electroplated Cu due to their similarity in hardness.

Properties of triacetatecellulose composite materials with additives tris[three (butoxy)(polyfluoroalkoxy)titaniumoxy] boranes

Studies have been performed on the modification of triacetatecellulose soluble compositions tris[three(butoxy)(polyfluoroalkoxy)titaniumoxy]boranes by the laboratories in which the length of the polyfluoroalkoxyl radical changed. At the initial stage, experiments were conducted to study the effect on the viscous characteristics of the initial solutions of TAC compositions of different temperature ranges, the values of the velocities of the concussion as for the initial base composition and with the introduction into the composition of the solution of different number of initial components, on the basis of which the target additives are synthesized, namely, polyfluoropic alcohol or tris[three(butoxy)titanoxy]borane. When introduced into the basic soluble composition of small amounts of polyfluorine alcohol FFА-3 (up to 0,1 % of the mass. from the mass of TAC) and a shear rate of 0,99c-1 there is a sharp increase in viscosity to 1,56 P·s, that is connected, apparently, with the implementation of a new type of hydrogen bonds between electronegative fluorine atoms and positively charged carbon atoms in the structure of solvents and TAC links (in complexes, simple ethers, glycosidic bonds and methylene groups at free hydroxylates). The implementation of such connections is accompanied by an increase in the volume of assocites, which are formed, ie indicates an increase in the viscosity of the solution of the sample TAC - composition. This interaction, with the formation of associations, takes place, first of all, on the surface of small supramolecular formations of TAC, obtained in the previous initial crushing of large supramolecular groups in solution. In this case, in the basic solution of the TAC-composition, there is a process of reversal of the TAC, namely, consolidation of the sizes of supramolecular formations. It is shown that the studied series of bor-, titanium-, (butoxy(polyfluoroalkoxy)-containing products, are effective modifiers of triacetate-cellulose soluble composite materials, allowing at the outflow stage, such as film materials or artificial silk threads, to adjust in a wide range, in the direction of increase, viscosity of the solution and at the same time increase the strength of finished products to break. The achievement of the obtained positive effect is due to the implementation in the polymer matrix of a new type of physical interactions between the electronegative fluorine atoms in the additive and the electropositive carbon atoms of the TAC molecule, as well as the coordination bonds between B and Ti additives and oxygen links TAC polymer. At the same time, internal stresses in the polymer matrix are reduced or virtually disappeared. Thus, studies have shown that polyfluoropic alcohols, tris- [three (butoxy)titanoxy]borane and products of its transesterification by polyfluoropic alcohols of different molecular weight are effective modifiers of soluble TAC compositions (as regulators of viscosity of solutions at the stage of outflow of films), and additives that increase the relative strength of their films by 2–3 times the strength of the films to break; their relative hardness), it is most advisable to use such a number of compounds in quantities of up to 1,0 % of the mass. from the mass of TAC. The obtained results can be used to significantly improve the quality of products from triacetatecellulose or in the recycling of products and waste on its basis.

Frozen strawberry quality enhancement using high hydrostatic pressure and vacuum infusion with pectin methylesterase and calcium chloride solution

Fresh strawberry(Fragaria x ananassa) is a delicious fruit that is an excellent source of micronutrients and an array of beneficial phytochemicals. Emerging technologies like high pressure freezing and thawing have gained interest recently due to their ability to preserve the structure of the food during storage, albeit the possible shortcomings of degradation of texture and sensory quality. In this study, the effects of high hydrostatic pressure freezing and thawing on the physical quality attributes (texture, drip loss and Degree of Methylation(DM)) of strawberry were investigated. Strawberry samples were infused in a vacuum using pectin methyl esterase(PME) and CaCl2solutionat170 hPa pressure for 5 min at room temperature to improve textural integrity; infused with distilled water; and another group of samples further incubated at 40°C for 20 min. Fresh samples and non-pre treated samples were also studied. All the samples were subjected to high pressure freezing and thawing processes at 200 MPa and the effect of the processing conditions on texture were evaluated. The high pressure processed samples were compared with conventionally frozen and thawed samples.Pectin methyl esterase,CaCl2infusion and incubation gave a relative hardness of 1.5 pre treatment compared to water only infused at 0.5.TheCaCl2and PME-infused samples had a higher relative hardness after one day of storage at -18°C compared to non-pretreated and water-infused samples at 0.3 compared to 0.1,respectively. Pretreated, water-infused, and PME withCaCl2-infused samples showed no significant difference in hardness when measured immediately after conventional thawing and high pressure induced thawing HPIT but are the former are a third less hard compared to the latter upon storage after 3 hours and three months. Galacturonic acid per mg of Alcohol insoluble residues AIR sample for the fresh strawberrywas0.002±2.699E-05 and 0.002±1.070E-05molesfor the one-day vs.three months storage,respectively,for samples conventionally frozen and thawed in duplicate experiments.Therefore,a combination of high-pressure shift freezing (HPSF) with PME and CaCl2infusion improved the texture of the strawberry compared to those that were not pretreated,and gained weight by 15%. The PME and CaCl2-infused strawberry showed less degradation than the non-pretreated and water-infused during both long-and short-time frozen storage. Conventional freezing processes caused more degradation compared to HPSF. Degradation of 3 months conventional freezing was comparable to 1-day storage. For frozen storage, enzyme pretreatment combined with high pressure freezing can be used to enhance the quality of strawberry.

An LSTM Approach for SAG Mill Operational Relative-Hardness Prediction

Ore hardness plays a critical role in comminution circuits. Ore hardness is usually characterized at sample support in order to populate geometallurgical block models. However, the required attributes are not always available and suffer for lack of temporal resolution. We propose an operational relative-hardness definition and the use of real-time operational data to train a Long Short-Term Memory, a deep neural network architecture, to forecast the upcoming operational relative-hardness. We applied the proposed methodology on two SAG mill datasets, of one year period each. Results show accuracies above 80% on both SAG mills at a short upcoming period of times and around 1% of misclassifications between soft and hard characterization. The proposed application can be extended to any crushing and grinding equipment to forecast categorical attributes that are relevant to downstream processes.

Strengthening Mechanisms and Tribological Properties of Ultra-Hard AlMgB14 Based Composite Reinforced with TiB2

AlMgB14–TiB2 composites with ideal structures are successfully prepared by field activated and pressure assisted synthesis. The effects of different TiB2 contents on the relative hardness and toughness of the composites were investigated. The results showed adding TiB2 could both increase the hardness of AlMgB14 and improve the fracture toughness. The TiB2 contributed more to the hardness than to the toughness. The microstructure analysis shows that the main toughening mechanisms of AlMgB14–TiB2 composites are hard phase dispersion strengthening, high-strength interface bonding and the high elastic modulus of TiB2. Therefore, reducing the particle size of TiB2 to nanoscale is an efficient way to improve the toughness and hardness. The results of friction and wear experiment at room temperature have shown that the addition of TiB2 into AlMgB14 enhances the abrasion–resistant property.

Experimental Examination of Process Parameters During Fabrication and Machining of Powder Metallurgy Aluminum Component

The present study aims at investigating the effect of process characteristics during fabrication and machining of powder metallurgy (PM) Aluminium cylindrical components. The application of the machining process as an alternate manufacturing process to fabricate the PM Aluminium components for industrial use with desired shape and size is explored. The PM Aluminium cylindrical components were fabricated by compacting the Aluminium metal powder within the compaction dies under various values of compaction load, sintering temperature and sintering time. These PM components were then machined under different standard cutting velocity and tangential cutting velocity, surface roughness data were analyzed. After the investigation it was concluded that, higher values of compaction load, sintering time and sintering temperature leads to higher values of relative density and relative hardness of the sintered Aluminum component. Again from machining results it can be stated that, higher values of fabricating parameters have a higher significance on performance parameters.

The extent of the ice sheet in the area of the Reykjanes Ridge at maximum of the last glaciation: new insights

<p>It is accepted that during the Last Glacial Maximum (LGM), about 21,000 years ago, the head of the Icelandic ice sheet was extending on a shelf area of the Iceland plateau, beyond the present-day coastline of the island. Attempts at locating the ice sheet edge were made many times, mainly on the basis of the recognition of the end moraines and other marginal glacial landforms on submerged parts of the Iceland plateau. There is, as yet, no full agreement on the exact reconstruction of the extent of the Icelandic ice sheet during the LGM. Both the thermodynamic models of the ice sheet and the glacial landforms discovered around Iceland indicate that the ice sheet has slipped onto (perhaps beyond) the insular shelf; however, determining the exact extent of the ice edge within its individual sectors can be problematic, mainly due to insufficient recognition of underwater glacial depositional or erosional landforms.</p><p>We present the results of the scientific expeditions A200608 from 2006 carried by former Marine Research Institute in Reykjavik on board R/V Árni Friðriksson and MSM75 from 2018 carried by GEOMAR on board the R/V Maria S. Merian. The aim of the study was a detailed geological characterization of the axial and near-axial part of the northern Reykjanes Ridge. The Kongsberg EM 300 30 kHz and Kongsberg EM712 75kHz multibeam echosounders were used (on A200608 and MSM75 cruises, respectively) to investigate the topography and surface morphology of the seafloor. In addition, acoustic backscatter was used to determine relative hardness of the substrate.</p><p>The bathymetry of the axial (neovolcanic) part of the Reykjanes Ridge, north of 63°N, indicates a rough bottom typical of the mid-oceanic ridge, made up of single hummocky volcanoes, hummocky ridges, shallow faults, volcanic cones and flat-top volcanoes. The last two types are characterized by steep, rough slopes and nearly circular shape. In both axial and off-axis areas, some volcanoes exhibit a dome-like structure with very smooth summits and slopes. Such volcanoes, in off-axis setting, most likely formed in the neovolcanic zone and migrated off-axis as the seafloor spreading progressed.</p><p>We suggest that observed domed-like volcanoes are the result of glacial erosion associated with the transgression and recession of the Icelandic ice sheet. High backscatter intensities indicate presence of a hard substrate (i.e. lava) on smooth summits and low intensities around dome-like volcanoes demonstrating potential direction of deposition of eroded material (or re-deposited by modern bottom currents). The research area has very slow sedimentation rate and strong bottom currents system; hence, there are no other geological processes (other than sedimentation) on the seafloor that could lead to such smoothening of these features and their evolution into dome-like volcanoes, especially in the neovolcanic zone where new seafloor is formed and rough terrain is observed.</p>