Effect of Accelerated Aging Temperature under Artificial Seawater on the Properties of Carbon Fiber/Epoxy Composites and the Erosion Mechanism

In order to explore the effect of artificial accelerated aging temperature on the performance of carbon fiber/epoxy resin composites,we used artificial seawater as the aging medium,designed the aging environment of seawater at different temperatures under normal pressure,and studied the aging behavior of carbon fiber/epoxy composites.The infrared spectroscopy results show that,with the increase of aging temperature,the degree of hydrolysis of the composite is greater.At the same time,after 250 days of aging of artificial seawater at regular temperature,40 and 60 ℃,the moisture absorption rates of composite materials were 0.45%,0.63%,and 1.05%,and the retention rates of interlaminar shear strength were 91%,78%,and 62%,respectively.It is shown that the temperature of the aging environment has a significant impact on the hygroscopic behavior and mechanical properties of the composite,that is,the higher the temperature,the faster the moisture absorption of the composite,and the faster the decay of the mechanical properties of the composite.

Population dynamics of marine ciliate Euplotes vannus (Protozoa, Ciliophora) in different artificial seawaters

To study population dynamics of marine ciliates in different artificial seawaters （ASW）, the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice media for five types of ASW and natural seawater （NSW）. The results show that： （1） the population growth rate was in the order of NSW〉Flack ASW〉Nakamula ASW〉Schmadz ASW〉Oshima ASW〉Subow ASW and was considerably higher in rice media than in beef extract media （apart from Subow ASW）; （2） the maximum density of E. vannus in stationary phase in each treatment was ranked as Hack ASW〉Nakamula ASW〉Schmadz ASW〉NSW〉Oshima ASW〉Subow ASW, and was again higher in rice media than in beef extract media （except for Subow ASW）; （3） the exponential and stationary phases were longer in rice media than in beef extract media; （4） strains of E. vannus that had been domesticated for 〉1 year in ASW grew significantly slower, with lower maximum density and longer stationary phase than those isolated and maintained in NSW. It was demonstrated that： （1） E. vannus may grow well in Flack, Nakamula and Schmads ASW compared with NSW （mainly in terms of growth rate）; and （2） Oshima ASW is the preferred choice for stock cultures of E. vannus, but the ASWs Flack, Nakamula and Schmadz are preferred for mass culture. These findings suggest that these three ASWs are effective for the cultivation of marine protozoa for experimental studies on ecology, toxicology and molecular biology.

Effects of small peptides, probiotics, prebiotics, and synbiotics on growth performance, digestive enzymes, and oxidative stress in orange-spotted grouper, Epinephelus coioides, juveniles reared in artificial seawater

Aquaculture production efficiency may increase by using feed additives. This study investigated the effects of different dietary additives [w/w: 2% small peptides, 0.01% probiotics( Bacillus licheniformis) and 0.2% prebiotics(inulin)] on growth performance, digestive enzyme activities, and oxidative stress in juvenile Epinephelus coioides reared in artificial seawater of two salt concentrations(13.5 vs. 28.5). Weight gain rate was significantly higher in fish fed the diet supplemented with small peptides, B. licheniformis, inulin, or synbiotics than that in fish fed the basal diet; the greatest weight gain rate was found in fish fed the small peptide treatment [56.0% higher than basal diet]. Higher feed efficiency was detected in fish fed the diet supplemented with small peptides than that of fish in the other dietary treatments. Total protease activity in the stomach and intestines was highest in fish fed the small peptide-treated diet, whereas lipase activity was highest in those fed synbiotics(combination of Bacillus licheniformis and inulin) than that in fish fed the other treatments. Antioxidant enzyme(total superoxide dismutase and catalase) activities and hepatic malondialdehyde content were higher in fish receiving the dietary supplements and maintained in artificial seawater containing 13.5 salinity compared with those in the control(28.5). Hepatic catalase activity in grouper fed the diets with small peptides or synbiotics decreased significantly compared with that in control fish. Overall, the three types of additives improved growth rate of juvenile grouper and digestive enzymes activities to varying degrees but did not effectively improve antioxidant capacity under low-salinity stress conditions.

Disinfection effect of adding slightly acidic electrolyzed water to artificial seawater under the condition of static hybrid

Mixed solution of slightly acidic electrolyzed water(SAEW)and artificial seawater was used to investigate the disinfection potential of SAEW in artificial seawater.Inoculated Vibrio parahaemolyticus(suspended in 3%sodium chloride alkaline peptone water and 0.85%sodium chloride water,respectively)was subjected to different mixed-SAEW and SAEW immersion treatments(5-20 mg/L available chlorine concentration(ACC)).In the presence of organic matter,4.07 logCFU/mL significant reduction(p<0.05)was achieved after treating with 20 mg/L mixed-SAEW for 15 min.There was 5.13 logCFU/mL reduction after treating with 15 mg/L SAEW for 15 min.For V.parahaemolyticus suspended in 0.85%sodium chloride solution,it was undetected after 30 s SAEW treatment(5 mg/L ACC)or 120 s mixed-SAEW treatment(10 mg/L ACC).At a ratio of SAEW and artificial seawater at 1:15(V/V),SAEW could inactivate V.parahaemolyticus to undetectable level in artificial seawater in one minute,which was comparable with UV treatment of 10 W.The results indicated high sanitization potential of SAEW against V.parahaemolyticus in aquaculture seawater.

Study of acoustic nonlinearity parameter B/A for seawater

The B/ A values of NaCl solution and arhficial seawater (prepared by LymanFleming formula) with different salinities and temperatures are measured and compared with the calculated B / A values in literature. The results show that the B / A values of NaCl solution increase linearly with increasing temperature and slightly with increasing salinity; the B / Avalues of artificial seawater increase linearly as temperature increases; basically, thc values match those obtained in literature[1]; NaCl solution can be used to simulate seawater approximately.