Triacetin as Lubricant Additive: Slipping Friction between Metal Pairs under Boundary Lubrication

Friction between rubbing pairs plays a key role in operating machines in an efficient approach. In some intended works or occasional circumstances, slipping friction may occur during dry or boundary lubrication. Lubricating mechanical equipment using proper and efficient lubricant agents is tremendously necessary. This work explores the synthesized triacetin as an additive for lubricant under slipping friction between steel rollers and aluminum, brass, copper, and stainless-steel rods under boundary lubrication. The metal surface morphology under the lubricant with 10% triacetin additive covering roughness periphery is investigated by Field Emission Scanning Electron Microscope imaging. In the dry slipping condition, the friction coefficient is lower for the copper-steel pair compared to the aluminum-steel combination. Compared to the absence of triacetin additive, the steel roller combinations with the rod metal specimens undergoing boundary lubrication with 10% triacetin additive in the lubricant can reduce the slipping friction coefficient by up to 49.2% in the case of steel roller and brass rod pair. The quantitative influences of triacetin additive on metal rubbing pair friction coefficients under boundary lubrication are inversely exponential correlated to triacetin additive, varying in the range of 0 to 10% v/v.

Propaedeutic Study of Biocomposites Obtained With Natural Fibers for Oceanographic Observing Platforms

In response to the pervasive anthropogenic pollution of the ocean, this manuscript suggests the use of biodegradable elastomers in marine applications. The present study characterizes 25 samples of highly biodegradable polymers, obtained blending a base elastomer with natural fibers. Mechanical analysis and Scanning Electron Microscope imaging, reveal how base polymers behave differently depending on the plant fiber chosen, on the external forcing—exposure to water—and on the doses that constitute the final biocomposite. Results suggest that EcoflexTM 00-30 and EcoflexTM 00-50, mixed with potato starch, perform best mechanically, maintaining up to 70% of their maximum tensile strain. Moreover, early signs of degradation are visible on polysiloxane rubber blended with 50% vegetable fibers after 19 hours in distilled water. Analyses demonstrate that highly biodegradable elastomers are good candidates to satisfy the requirements of aquatic devices. Furthermore, the discussed materials can improve the dexterity and biodegradability of marine technology.

Automated Metrology on the Verticality of Cross-Sectioned Channel Hole at V-NAND with Over 200 Layers by Transmission Electron Microscope

In this paper, we present a nanoscale verticality measurement method for V-NAND with 200 or more layers of high layers using an automated transmission electron microscope, which has been developed a lot in the analysis field. Nanoscale measurements in cross-sectional images in 3D-NAND with such a high layer do not include both the top and bottom areas in one image of FOV. Therefore, it is very difficult for a person to objectively measure the etching angle or verticality of the channel hole. We experimented the verticality measurement of a channel hole in the two images in different areas using an automated transmission electron microscope imaging and measurement. In this paper, we present the results and analysis of the experiment and detailed metrology methods.

Insect Preservation Methods Allow Quantification of Dispersing Microorganisms by Scanning Electron Microscopy

Insects may act as dispersal vectors for microbes where microbes can temporarily adhere to insect exoskeletons. Microbes carried by honey bees (Apis mellifera) may experience a range of dispersal outcomes, from successful colonisation of a new habitat to predation by grooming bees, partly depending on their location on the bee exoskeleton and the carried population size. I tested four methods for handling collected bees, and examined the bees in a scanning electron microscope, imaging and counting microbial cells attached to tarsal claws. Freeze-dried bees carried more microbial cells than bees that were pinned and air-dried, preserved in 96% ethanol then dried by CO2 critical-point drying, or bees washed with potassium phosphate then preserved in 96% ethanol, but some microbes were found on bees from every treatment. The similarity in microbial passengers found between air-dried and ethanol-preserved bees suggests that examination by electron microscopy could be used to address questions regarding microbial dispersal by pollinators already present in collections associated with other pollination research.

Efficiency of Extremophilic Microbial Mats for Removing of Pb(II), Cu(II) and Ni(II) ions from Aqueous Solutions

Two different extremophilic films were used as natural biosorbents to remove Cu(II), Ni(II) and Pb(II) from aqueous solution. Surface area, scanning electron microscope imaging and Fourier transformation infrared were used to characterize the surface of biosorbents. The results indicated high affinity of biosorbents to remove Pb(II) Cu(II) and Ni(II) with adsorption ratio ranged between 73.6–100% for both two biosorbent. The two biosorbents success to remove the metal ions from the aqueous mixture in the order of Pb(II) > Cu(II) > Ni(II). The maximum removal ratios of metal ions were achieved at pH = 6, 150 min contact time, 2.5 g/L biosorbent dose and 50 mg/L metal ions. The isothermal studies showed that both Langmuir and Freundlich models well expressed the adsorption process. Kinetically, the pseudo-second order reaction well express the type of reaction than pseud-first order reaction.

Redeposition experiments with natural sediments from the SE Black Sea in magnetic fields between about 2 and 114 µT

SUMMARY Diluted slurry with an initial density of 1.30 g cm−3 prepared from natural glacial Black Sea sediments was deposited under controlled field conditions between 1.72 and 114.21 µT. Compaction was achieved by evaporation of a portion of the pore water from the open sample boxes over 4–7 d until a density of about 1.44–1.55 g cm−3 was reached. Magnetizations M acquired in a magnetic field B follow a slightly non-linear function with M ∼ B0.82. Similar relationships were also obtained for palaeointensity estimates for the artificial samples by using normalization by low-field susceptibility, anhysteretic remanent magnetization and saturation magnetization. All samples are characterized by a magnetic fabric typical for natural sediments as checked by determining the anisotropy of magnetic susceptibility. The sediments’ anisotropy is in the range of 6–7 per cent and it is characterized by an oblate anisotropy ellipsoid with its small axis perpendicular to the deposition plane. According to scanning electron microscope imaging low-Ti magnetite particles present in the used sediments are in the range of 1–30 µm with the majority of particles 2–5 µm in size. Obtained results confirm the conclusion from other magnetostratigraphic studies that the Laschamps geomagnetic polarity excursion in the Black Sea area exhibited field values as low as 2.8 µT in its transitional phase between normal and reversed polarity.

Novel hemodynamic structures in the human glomerulus

To investigate human glomerular structure under conditions of physiological perfusion, we have analyzed fresh and perfusion-fixed normal human glomeruli at physiological hydrostatic and oncotic pressures using serial resin section reconstruction, confocal, multiphoton, and electron microscope imaging. Afferent and efferent arterioles (21.5 ± 1.2 µm and 15.9 ± 1.2 µm diameter), recognized from vascular origins, lead into previously undescribed wider regions (43.2 ± 2.8 µm and 38.4 ± 4.9 µm diameter) we have termed vascular chambers (VCs) embedded in the mesangium of the vascular pole. Afferent VC (AVC) volume was 1.6-fold greater than efferent VC (EVC) volume. From the AVC, long nonbranching high-capacity conduit vessels ( n = 7) (Con; 15.9 ± 0.7 µm diameter) led to the glomerular edge, where branching was more frequent. Conduit vessels have fewer podocytes than filtration capillaries. VCs were confirmed in fixed and unfixed specimens with a layer of banded collagen identified in AVC walls by multiphoton and electron microscopy. Thirteen highly branched efferent first-order vessels (E1; 9.9 ± 0.4 µm diameter) converge on the EVC, draining into the efferent arteriole (15.9 ± 1.2 µm diameter). Banded collagen was scarce around EVCs. This previously undescribed branching topology does not conform to the branching of minimum energy expenditure (Murray’s law), suggesting that even distribution of pressure/flow to the filtration capillaries is more important than maintaining the minimum work required for blood flow. We propose that AVCs act as plenum manifolds possibly aided by vortical flow in distributing and balancing blood flow/pressure to conduit vessels supplying glomerular lobules. These major adaptations to glomerular capillary structure could regulate hemodynamic pressure and flow in human glomerular capillaries.