Evaluating Stability of Aqueous Multiwalled Carbon Nanotube Nanofluids by Using Different Stabilizers

The 0.5 wt.% multiwalled carbon nanotubes/water nanofluids (MWNFs) were produced by using a two-step synthetic method with different types and concentrations of stabilizers. The static position method, centrifugal sedimentation method, zeta potential measurements, and rheological experiments were used to assess the stability of the MWNFs and to determine the optimal type and fixed MWCNTs-stabilizer concentration of stabilizer. Finally, MWNFs with different concentrations of MWCNTs were produced using the optimal type and fixed concentration ratio of stabilizer, and their stability, thermal conductivity, and pH were measured to assess the feasibility of using them in heat transfer applications. MWNFs containing SDS and SDBS with MWCNTs-stabilizer concentration ratio were 5 : 2 and 5 : 4, respectively, showed excellent stability when they were evaluated by static position, centrifugal sedimentation, zeta potential, and rheological experiments at the same time. The thermal conductivity of the MWNFs indicated that the most suitable dispersing MWNF contained SDBS. MWNFs with MWCNTs concentrations of 0.25, 0.5, and 1.0 wt.% were fabricated using an aqueous SDBS solution. In addition, the thermal conductivity of the MWNFs was found to have increased, and the thermal conductivity values were greater than that of water at 25°C by 3.20%, 8.46%, and 12.49%

Preparation and Characterization of Carbon Nanofluids by Using a Revised Water-Assisted Synthesis Method

A revised water-assisted synthesis system (RWAS) was used to fabricate carbon/water nanofluids (CWNFs). The CWNFs were manufactured by heating graphite rods at different temperatures (700, 800, 900, and 1000°C). Aspects of the CWNFs and suspended nanocarbon, such as the morphology, structure, optical characteristics, and production rate, were fully characterized. Furthermore, the suspension performance of the CWNFs was controlled by adding a dispersant (water-soluble chitosan) at different concentrations. Finally, the CWNFs were determined to assess the influence of both the heating temperature of the graphite rod module (process temperature) and the dispersant concentration on the fundamental characteristics of the CWNFs. The results showed that the nanocarbon was a mixture of nanocrystalline graphite and amorphous carbon. Heating the graphite rod module at higher process temperatures resulted in a higher production rate and a greater nanocarbon particle size. Furthermore, adding dispersant could improve the suspension performance; increase the viscosity, density, and specific heat; and reduce the thermal conductivity of the CWNFs. The optimal combination of the process temperature range and dispersant concentration was 800 to 900°C and 0.2 wt.%, respectively, based on the production rate, suspension performance, and other fundamental properties of the CWNFs

The role of PIT1 in the putative quantitative trait loci region on pig chromosome 13

PIT1 is an essential regulatory gene of growth hormone (GH), prolactin (PRL) and thyrotropin beta subunit. Previously, PIT1 polymorphisms and the chromosomal region near PIT1 in multiple pig populations is significantly associated with fatness and growth quantitative trait loci (QTLs) on pig chromosome 13. The purpose of this study is to confirm these previous results and clarify the role of the PIT1 gene in the putative QTL region;Cloning of the full length PIT1 cDNA was completed. The pig PIT1 cDNA and its deduced amino acids have approximately 90% and 95% sequence similarity respectively with the PIT1 cDNA and amino acids in other species. Several PIT1 alternative spliced forms were also identified. The Delta3PIT1, which is missing the entire exon 3, was unique to pig. Potentially different functions of the pig Delta3PIT1 from PIT1 were analyzed. The pig PIT1 protein could specifically bind to the rat GH and PRL promoter regions while the pig Delta3PIT1 protein could not. Possible protein-protein interactions between Delta3PIT1 and PIT1 were tested. Delta3PIT1 protein was shown to not affect PIT1 DNA binding. The results of functional studies revealed that PIT1 could play an important role in pig growth as it does in other species;Analyses of additional populations detected an association between PIT1 and birth weight, confirming the previous studies. Growth and carcass traits in the ISU F2 families were analyzed and four microsatellite markers flanking the PIT1 gene were included. The data were analyzed using interval mapping and single marker methods. Significant evidence of a QTL for first rib backfat thickness was detected approximately 20 cM away from PIT1 by using interval mapping analyses, and linkage disequilibrium between PIT1 and the backfat QTL was shown in single marker analyses. Evidence of a QTL for birth weight was detected at the estimated PIT1 position in interval mapping analyses and verified by the single marker analyses. The results of QTL analyses confirmed the previous published QTL work on pig chromosome 13 for the birth weight QTL, but suggest that other genes in the region are responsible for the detected backfat thickness QTL.</p

Fabrication and Characterization of Carbon-Based Nanofluids through the Water Vortex Trap Method

This study designed an efficient one-step method for synthesizing carbon-based nanofluids (CBNFs). The method employs the vortex trap method (VTM) and an oxygen-acetylene flame, serving as a carbon source, in a manufacturing system of the VTM (MSVTM). The flow rate ratio of O2 and C2H2 was adjusted to form suitable combustion conditions for the reduced flame. Four flow rate ratios of O2 and C2H2 were used: 1.5 : 2.5 (V1), 1.0 : 2.5 (V2), 0.5 : 2.5 (V3), and 0 : 2.5 (V4). The morphology, structure, particle size, stability, and basic physicochemical characteristics of the obtained carbon-based nanomaterials (CBNMs) and CBNFs were investigated using transmission electron microscopy, field-emission scanning electron microscopy, X-ray diffraction, Raman spectrometry, ultraviolet–visible–near-infrared spectrophotometry, and a particle size-zeta potential analyzer. The static positioning method was utilized to evaluate the stability of the CBNFs with added EP dispersants. The evaluation results revealed the morphologies, compositions, and concentrations of the CBNFs obtained using various process parameters, and the relation between processing time and production rate was determined. Among the CBNMs synthesized, those obtained using the V4-0 flow rate ratio had the highest stability when no EP dispersant was added. Moreover, the maximum enhancement ratios of the viscosity and thermal conductivity were also obtained for V4-0: 4.65% and 1.29%, respectively. Different types and concentrations of dispersants should be considered in future research to enhance the stability of CBNFs for further application

由皮亞傑的發生認識論探討發現問題的機制

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Highly Transparent and Polarization-Maintained Terahertz Plasmonic Metamaterials Based on Metal-Wire-Woven Hole Arrays: Fundamentals and Characterization of Transmission Spectral Peaks

Metal-hole-supported terahertz (THz) waves through the structure of a metal-wire-woven hole array (MWW-HA) present high-frequency-passed transmittance spectra of one plasmonic metamaterial with artificial plasmonic frequencies, which are inversely proportional to metal-hole widths. For the transmitted THz waves of MWW-HA, transverse-electric (TE) and transverse-magnetic (TM) waveguide modes mix within a symmetric metal-hole boundary. THz resonance waves transversely crossing the holes of MWW-HA are experimentally characterized with spectral peaks in the frequency range of 0.1&ndash;2 THz that are correlated with aperture sizes, unit-cell-hole widths, metal-wire thicknesses, and wire-bending angles. The metal-hole-transported resonance waves of MWW-HA are dominated by TE waveguide modes instead of TM ones because a hole width of MWW-HA is approximate to the half wavelength of a resonance wave. The round metal edges of the woven metal wires can minimize the effective optical length of a thick metal hole to transmit THz resonance waves, thereby resulting the smallest rotation angle of linear polarization and high transmittance up to 0.94. An MWW-HA structure is therefore reliable for supporting metal-hole resonance waves with low resistance, whereas a metal-slab-perforated hole array cannot achieve the same result

Development of Inner-Grooved Tubes by Dieless Micro-Forming with Laser-as-Sisted Air Pressure

Grooved tubes are widely used in electronic cooling modules. They are usuallt drawn, a term referring to molding. However, this process has limitations, especially in the production of smaller tubes. Therefore, this study examines the potential of an alternative process, dieless forming, in which the grooves on stainless steel are generated by pulsed laser-assisted air pressure. To begin with, the stainless steel tube in ambient air was heated using a pulsed laser. Then, groove samples were sliced for observation using an optical microscope (OM). Finally, the samples were analyzed using Scanning Electronic Microscope (SEM). The results demonstrate that grooves can be formed utilizing dieless forming with pulsed laser-assisted air pressure. The average observed depth of the grooves 208.5 um at 10-watt power and 0.01 Mpa gas pressure. In conclusion, grooves at a micro scale can be produced effectively by dieless forming for a range of industrial applications