Cushioning Performance of the Biomimetic Cobweb Cushioning Silicone Pad.

At present, the packing method of "plastic bag-buffer packing-packing paper box" is adopted for bearing packaging. However, the common packing method has a poor packing effect and poor versatility. In this study, a new biomimetic cobweb cushion is proposed to solve the problem of insufficient cushioning capacity of high-precision bearing cushion packaging pads. First, according to the nature of cobweb form, the cobweb cushion structure configuration is determined. Next, based on the structure of the cushion and the relationship between the parameters of radial thread and spiral thread, a mechanical and target optimization model is established. The stress nephogram of bearing and the cobweb cushion are analyzed under three drop heights of 381, 610, and 700 mm, in the finite element simulation software to ensure that the maximum bearings stress is not beyond the material yield strength. Via the 3D printing technology, a cobweb cushion shell cast is made. Drop tests of the bearing were performed, and the results were verified with the finite element simulation analysis. This research can provide technical support for the protection of high-precision bearings from accidental drops during transportation.

Vibrio splendidus Fur regulates virulence gene expression, swarming motility, and biofilm formation, affecting its pathogenicity in Apostichopus japonicus.

Vibrio splendidus is an opportunistic pathogen that causes skin ulcer syndrome and results in huge losses to the Apostichopus japonicus breeding industry. Ferric uptake regulator (Fur) is a global transcription factor that affects varieties of virulence-related functions in pathogenic bacteria. However, the role of the V. splendidus fur (Vsfur) gene in the pathogenesis of V. splendidus remains unclear. Hence, we constructed a Vsfur knock-down mutant of the V. splendidus strain (MTVs) to investigate the role of the gene in the effect of biofilm, swarming motility, and virulence on A. japonicus. The result showed that the growth curves of the wild-type V. splendidus strain (WTVs) and MTVs were almost consistent. Compared with WTVs, the significant increases in the transcription of the virulence-related gene Vshppd mRNA were 3.54- and 7.33-fold in MTVs at the OD600 of 1.0 and 1.5, respectively. Similarly, compared with WTVs, the significant increases in the transcription of Vsm mRNA were 2.10- and 15.92-fold in MTVs at the OD600 of 1.0 and 1.5, respectively. On the contrary, the mRNA level of the flagellum assembly gene Vsflic was downregulated 0.56-fold in MTVs at the OD600 of 1.0 compared with the WTVs. MTVs caused delayed disease onset time and reduced A. japonicus mortality. The median lethal doses of WTVs and MTVs were 9.116 × 106 and 1.658 × 1011 CFU·ml-1, respectively. Compared with WTVs, the colonization abilities of MTVs to the muscle, intestine, tentacle, and coelomic fluid of A. japonicus were significantly reduced. Correspondingly, the swarming motility and biofilm formation in normal and iron-replete conditions were remarkably decreased compared with those of WTVs. Overall, these results demonstrate that Vsfur contributes to the pathogenesis of V. splendidus by regulating virulence-related gene expression and affecting its swarming and biofilm formation abilities.

Dual Alkali Solvent System for CO2 Capture from Flue Gas.

A novel two-aqueous-phase CO2 capture system, namely the dual alkali solvent (DAS) system, has been developed. Unlike traditional solvent-based CO2 capture systems in which the same solvent is used for both CO2 absorption and stripping, the solvent of the DAS system consists of two aqueous phases. The upper phase, which contains an organic alkali 1-(2-hydroxyethyl) piperazine (HEP), is used for CO2 absorption. The lower phase, which consists of a mixture of K2CO3/KHCO3 aqueous solution and KHCO3 precipitate, is used for CO2 stripping. Only a certain kind of amine (such as HEP) is able to ensure the phase separation, satisfactory absorption efficiency, effective CO2 transfer from the upper phase to the lower phase, and regeneration of the upper phase. In the meantime, due to the presence of K2CO3/KHCO3 in the lower phase, HEP in the upper phase is capable of being regenerated from its sulfite/sulfate heat stable salt, which enables the simultaneous absorption of CO2 and SO2/SO3 from the flue gas. Preliminary experiments and simulations indicate that the implementation of the DAS system can lead to 24.0% stripping energy savings compared to the Econamine process, without significantly lowering the CO2 absorption efficiency (∼90%).

Tracking of arsenics during the thermal stabilization of an AsH3 scrubber sludge.

Toxic arsenics in an AsH(3) scrubber sludge were thermally stabilized in the temperature range of 973-1,373 K. To better understand how the high-temperature treatments can stabilize arsenics in the sludge, their synchrotron X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra of arsenics were determined. It is found that the reduced arsenic leachability may be associated with the formation of As(2)O(5) (51-59%) and embedded As(V) within the Ca(3)(PO(4))(2) matrix (41-49%) in the stabilized sludge. In addition, the As-O bond distances in the stabilized As(2)O(5) are much less than that of normal As(2)O(5) by 0.05-0.07 Å. The shorter As-O bond distances accompanied with the higher bonding energy also have a contribution to the thermal stabilization of arsenics.

Nanosize copper encapsulated carbon thin films on a dye-sensitized solar cell cathode.

Deposition of the nanosize copper encapsulated carbon (Cu@C) thin film onto the cathode has been studied to enhance efficiency of the dye-sensitized solar cell (DSSC). The X-ray diffraction (XRD) patterns of the Cu@C are suggestive of existence of metallic copper (Cu) nanoparticles in the thin film. The UV-visible spectrum of the Cu@C coated on indium-doped tin oxide (ITO) shows a red shift (probably due to the longitudinal resonance) as the size of Cu in the Cu@C increases. Moreover, the images observed by field-emission scanning electron microscopy (FE-SEM) indicate that the Cu@C nanoparticles are well dispersed on ITO. By extended X-ray absorption fine structure (EXAFS) spectroscopy, a decrease of the coordination number (CN) of Cu-Cu with decreasing sizes of Cu in the Cu@C is observed. Interestingly, an enhanced efficiency of the DSSC with the Cu@C nanoparticles coated ITO cathode by 50% is found if compared with the relatively expensive Pt electrode. As the size of Cu in the Cu@C on ITO decreases (e.g., 20 --> 7 nm), the efficiency of the DSSC can be increased by 80% approximately.

Pyrolysis of spill oils adsorbed on zeolites with product oils recycling.

Experimentally, a feasibility study for adsorption and catalytic pyrolysis of spill oils on Cu/ZSM-5 for recycling of light oils has been conducted in the present work. The adsorption and pyrolysis of model compounds such as heptane, toluene, and diesel (to stimulate the spill oils) on Cu/ZSM-5 have been investigated on a continuous fixed-bed reactor. By component fitted X-ray absorption near edge structural (XANES) spectroscopy, catalytic active species such as metallic copper (Cu) (77-84%) and Cu(2)O (6-7%) are found in the channels of ZSM-5 during pyrolysis of heptane or toluene. Pyrolysis of diesel effected by Cu/ZSM-5 yields gas (C(1)-C(5)) (32%) and light oil (68%) that can be used as auxiliary fuels.