Search

[Display omitted] • Polyvinyl alcohol/Poly (styrene-maleic anhydride) nanofiltration membranes were fabricated through a green surface crosslink method. • The nanofiltration membrane has a gradiently cross-linked structure with bottom dense and top loose. • The PVA/SMA-PES membrane has excellent anti-fouling and dye/salt separation performance. Nanofiltration membranes with excellent anti-fouling properties were fabricated through a green surface crosslink method. Poly (styrene-maleic anhydride) (SMA) blended polyethersulfone (PES) membrane was used as a support. The SMA in the PES support served as a macromolecular crosslinker. After coating of polyvinyl alcohol (PVA) on the surface of the SMA-PES support, a PVA selective layer with gradient cross-linked structure was formed, through the esterification between the anhydride groups in SMA and the hydroxyl groups in PVA. This process adopts a full-water fabrication strategy without secondary pollution. The gradiently cross-linked PVA/SMA-PES membrane, with molecular weight cut-off (MWCO) about 600 Da and permeance around 10-12 L/(m2·h·bar), exhibited good dye/salts separation performance. In the filtration of a mixed solution of Congo Red (CR) and calcium chloride (CaCl 2), the membrane rejected 98% CR and only had 10% rejection of CaCl 2. In addition, this membrane processed an excellent anti-fouling property. In the BSA fouling test, the pure water flux recovery ratio (FRR) was 99%. It is expected that the PVA/SMA-PES membrane can be used in organic desalination. [ABSTRACT FROM AUTHOR]

Variable speed steering system has been used by cars of various brands, including BMW and Toyota, with the purpose of improving the stationarity and controllability of the vehicle. Until now, relevant investigations are focused on the theory and traditional application, while the geometric characteristics and tooth modification for the rack are left untouched upon, hindering the prospect of a wider application. Focusing on this, the paper synthesizes the mathematical model, geometry characteristics, and tooth modification method for the variable pinion–rack drive. The major contributions lie in the contact analysis and the modification methodology for the pinion–rack drive, which combined forms a solid foundation for the application that has never been discussed.

The preparation, approximate composition, degree of hydrolysis (DH), lipase activity and antioxidant capacity (including the ability of scavenging DPPH and ABTS free radicals) were determined for various of aqueous enzymatic extract (AEE) obtained from rice bran (RB) using alcalase (A), trypsin (T), papain (Pn), neutrase (N) and protamex (Px). Peptides and γ-oryzanol are the major functional components of AEE. Generally, the protein yield varied with the type of enzyme used in the order of T>Pn>N>Px>A. Both trypsin and alcalase extracts exhibit a higher level of γ-oryzanol than other enzymes. Lipase activity was measured using the 4-Nitrophenyl Laurate (p-NPL) substrate method, and significantly different (P<0.05) lipase activity values ranging from 0.55 to 2.38 mU/mL were observed from five hydrolysates. Furthermore, two synthetic free radicals were used to evaluate the antioxidant activity of AEE. The alcalase extract (at 4.35±0.15mg protein/mL AEE) shows the greatest scavenging rate (28.42%) of DPPH, but trypsin extract has highest ABTS radical-scavenging activity of 94.05%. Data revealed trypsin was possible the most effective extractant under their optimal conditions. These results demonstrate that the product obtained from rice bran by different enzymatic digestions may contain bioactive components and might potentially be natural antioxidants. Meanwhile, the aqueous enzymatic extraction method can also improve the stability of the hydrolysates.

The ticks of the subgenus Indocentorunder the genus Dermacentorfrom China are reviewed with two new records. Besides reviewing Dermacentor auratusand Dermacentor taiwanensis, the anomalies in the distinction of Dermacentor compactusand Dermacentor steini, usually incorrectly identified as D. auratus, are brought out. A key to the identification of these is also provided.

This paper focuses on the effect by sodium sulfite on the enzyme activity and stabilization of rice bran. First, enzymes are studied by detecting the activity of lipase and peroxidase. Then the total antioxidant capacity is tested in order to clarify the effect of sodium sulfite on antioxidant substances. Finally, processed rice bran is storaged in constant temperature to observe the change of fatty acid and peroxide value. The optimal condition is 4% sodium sulfite for 150min. The results show that the sodium sulfite can reduce the enzyme activity to improve the stability of rice bran.

In the research of rice bran stabilization, most of the literature only study the lipase which is explained by the changes in free fatty acids in the storage experiment or peroxidase activity. It leads results not comprehensive, extends the experiment time, increases the experimental difficulty and wastes of manpower and material resources. For the first time, the effect of heat treatment on fresh rice bran stability is examined in terms of direct determination of water content, lipase activity, peroxidase activity and total antioxidant capacity. The optimal condition is that 120 degrees for 22 min. The results show that the heat treatment can reduce the enzyme activity of rice bran to improve the stability of rice bran.

Under the conditions of temperature of 20deg C and transmembrane pressure of 0.2MPa, a silicon carbide membrane with a pore size of 0.04um was introduced to treat pure terephthalic acid (PTA) wastewater with the dead end filtration method. The membrane was found to exhibit high flux as 1987L/(m2*h), the solid content decreased from 0.501% to 0.003 %, the COD decreased from 23345.40mg/L to17862.11mg/L. The flux recovery rate was achieved 97.6% and 100% after back flushing and membrane cleaning respectively.