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Plastic take-out food containers may release microplastics (MPs) into food and pose a potential risk to food safety and human health. Here, after being subjected to hot water treatment, MPs released from three types of plastic food containers (polypropylene, PP; polyethylene, PE; expanded polystyrene, EPS) were identified by micro-Raman spectroscopy. The results showed that the size of released MPs ranged from 0.8–38 μm and over 96% MPs were smaller than 10 μm. Various MPs concentrations were found from the three types of containers, that is, 1.90 × 104, 1.01 × 105, and 2.82 × 106 particles/L on average from PP, PE, and EPS, respectively. Moreover, based on thermal and morphology analysis, we discovered that both relaxations of the polymer chains in the rubbery state and defects caused by processing techniques might contribute to the release of MPs. Thus, such release can be reduced by increasing the thermal stability of the materials and mitigating the defects generated during production. [ABSTRACT FROM AUTHOR]

Diglycolamides (DGAs) belong to the class of "CHON" type compounds and can form tridentate complexes with metal ions. DGA-based extractants are a subject of great interest in actinide partitioning due to their exceptionally high affinity for trivalent actinides and lanthanides. Since the separation performance of DGAs are closely related to their molecular structures, many structure-modification schemes have been proposed such as the attachment of different alkyl substituents to an amidic N atom or anchoring multiple DGA arms onto a scaffold. In this paper, literature reports that describe the effects of such modifications on the structure and performance of DGAs are summarized. By comparing the extraction and separation properties of DGA extractants with different structures, the relationship between the structure and properties of DGAs is discussed. Such work should be helpful for gaining a more comprehensive, accurate and in-depth understanding of the relationship between structure and property of DGAs to be developed. It should also be beneficial for the structural design of more new DGA extractants. [ABSTRACT FROM AUTHOR]

Nitrogen oxides conversion rate, ammonia slip, and urea crystallization are major problems in the application of the selective catalytic reduction systems of diesel engine. Based on the bench test, the selective catalytic reduction system model was proposed with the code AVL Fire to investigate these problems. The research results indicate that the increasing ammonia/nitrogen oxides feed ratio contributes to reduce the emission of nitrogen oxides. However, the excessive supply of urea-water solution causes the increase of ammonia slip and liquid film. Nitrogen oxides conversion rate reaches a higher level when the exhaust temperature is 450°C. The performance of the system goes worse as the exhaust flow rate increases. The location of the mixer has a huge impact on the flow streamline. The formation of the liquid film and the interaction between the pipe and the droplets depend on the flow streamline. The mixer location is optimized to reduce the quantity of ammonia slip and liquid film based on the numerical study. [ABSTRACT FROM AUTHOR]

In the present work, a numerical method is utilized to simulate the nucleate pool boiling of R134a outside the horizontal plain tube. Eulerian multiphase model integrated with Rensselaer Polytechnic Institute (RPI) nucleate boiling model is adopted. The nucleate pool boiling is numerically investigated at the heat flux of 20–80 kW/m2 and saturation temperatures of 279 and 299.7 K. By analyzing the experimental results, a modified correlation of active nucleation site density is proposed. The numerical results based on the modified correlation agree well with the experimental data of the pool boiling heat transfer outside the plain tube. According to the simulation of azimuthal variations of temperature around the tube, it is found that the region between 90° and 130° has the best heat transfer performance for its high velocity and turbulence. The maximum temperature appears at the upper of the tube because the velocity and turbulence intensity at this region are lower. The investigation helps to explain the phenomena and observed facts in the experiment. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of surface wettability on the pool boiling heat transfer, nucleate pool boiling experiments were conducted with deionized water and silica based nanofluid. A higher surface roughness value in the range of 3.9 ~ 6.0μm was tested. The contact angle was from 4.7° to 153°, and heat flux was from 30kW/m2 to 300kW/m2. Experimental results showed that hydrophilicity diminish the boiling heat transfer of silica nanofluid on the surfaces with higher roughness. As the increment of nanofluid mass concentration from 0.025% to 0.1%, a further reduction of heat transfer coefficient was observed. For the super hydrophobic surface with higher roughness (contact angle 153.0°), boiling heat transfer was enhanced at heat flux less than 93 kW/m2, and then the heat transfer degraded at higher heat flux. [ABSTRACT FROM AUTHOR]

The falling film evaporation of R134a with nucleate boiling outside a triangular-pitch (2-3-2-3) tube bundle is experimentally investigated, and the effects of saturation temperature, film flow rate and heat flux on heat transfer performance are studied. To study the effect of cross vapor stream on the falling film evaporation, a novel test section is designed, including the tube bundle, liquid and extra vapor distributors. The measurements without extra vapor are conducted at the saturation temperature of 6, 10 and 16°C, film Reynolds number of 220 to 2650, and heat flux of 20 to 60 kWm−2. Cross vapor stream effect experiments are operated at three heat fluxes 20, 30, and 40 kWm−2 and two film flow rates of 0.035 and 0.07 kgm−1s−1, and the vapor velocity at the smallest clearance in the tube bundle varies from 0 to 2.4 ms−1. The results indicate that: film flow rate, heat flux and saturation temperature significantly influence the heat transfer; the cross vapor stream either promote or inhibit the falling film evaporation, depending on the tube position, film flow rate, heat flux and vapor velocity. [ABSTRACT FROM AUTHOR]

Context:The defatted seeds ofCamellia oleiferavar.monospermaHung T. Chang (Theaceae) are currently discarded without effective utilization. However, sapogenin has been isolated and shows antioxidative, anti-inflammatory and analgesic activities suggestive of its neuroprotective function. Objective: In order to improve the activities of sapogenin, the nanoparticles of iron–sapogenin have been synthesized, and the neuroprotective effects are evaluated. Materials and methods:Structural characters of the nanoparticles were analyzed, and the antioxidant effect was assessed by DPPH method, and the neuroprotective effect was evaluated by rotenone-induced neurodegeneration in Kunming mice injected subcutaneously into the back of neck with rotenone (50 mg/kg/day) for 6 weeks and then treated by tail intravenous injection with the iron–sapogenin at the dose of 25, 50 and 100 mg/kg for 7 days. Mice behaviour and neurotransmitters were tested. Results:The product had an average size of 162 nm with spherical shape, and scavenged more than 90% DPPH radicals at 0.8 mg/mL concentration. It decreased behavioural disorder and malondialdehyde content in mice brain, and increased superoxide dismutase activity, tyrosine hydroxylase expression, dopamine and acetylcholine levels in brain in dose dependence, and their maximum changes were respectively up to 60.83%, 25.17%, 22.13%, 105.26%, 42.17% and 22.89% as compared to vehicle group. Iron–sapogenin nanoparticle shows significantly better effects than the sapogenin. Discussion and conclusion:Iron–sapogenin alleviates neurodegeneration of mice injured by neurotoxicity of rotenone, it is a superior candidate of drugs for neuroprotection. [ABSTRACT FROM AUTHOR]