Analysis of Entrainment Ratio about Solar Ejector Refrigerant System

AbstractBased on the VB program, establish a simulation program about the solar ejector system performance. The characteristic of entrainment ratio has been analyzed when the HFC134a, R290 and R718 are adopted as working fluid respectively. It is found that the entrainment ratio of R290 is the biggest over the range of operating conditions, and the entrainment ratio of HFC134a is the middle, and the R718's is the least. The entrainment ratio of the system increases with increasing of the generator temperature and evaporator temperature, and decreases with increasing of the condenser temperature in the research of operating range, and the influence of condenser temperature on the ejector refrigerant system is more than the generator temperature and evaporator temperature. The research will provide theoretical support for solar ejector refrigeration technology optimization design and extension

Perioperative probiotics attenuates postoperative cognitive dysfunction in elderly patients undergoing hip or knee arthroplasty: A randomized, double-blind, and placebo-controlled trial

BackgroundPostoperative cognitive dysfunction (POCD) is a common complication in elderly patients following surgery. The preventive and/or treatment strategies for the incidence remain limited.ObjectiveThis study aimed to investigate the preventive effect of perioperative probiotic treatment on POCD in elderly patients undergoing hip or knee arthroplasty.MethodsAfter obtaining ethical approval and written informed consent, 106 patients (age ≥60 years) were recruited, who scheduled elective hip or knee arthroplasty, from 16 March 2021 to 25 February 2022 for this randomized, double-blind, and placebo-controlled trial. They were randomly assigned with a 1:1 ratio to receive either probiotics or placebo treatment (four capsules, twice/day) from hospital admission until discharge. Cognitive function was assessed with a battery of 11 neuropsychological tests on the admission day and the seventh day after surgery, respectively.ResultsA total of 96 of 106 patients completed the study, and their data were finally analyzed. POCD occurred in 12 (26.7%) of 45 patients in the probiotic group and 29 (56.9%) of 51 patients in the placebo group (relative risk [RR], 0.47 [95% confidence interval [CI], 0.27 to 0.81]; P = 0.003). Among them, mild POCD occurred in 11 (24.4%) in the probiotic group and 24 (47.1%) in the placebo group (RR, 0.52 [95% CI, 0.29 to 0.94]; P = 0.022). No significant difference in severe POCD incidence was found between the two groups (P = 0.209). Compared with the placebo group, the verbal memory domain cognitive function was mainly improved in the probiotic group.ConclusionProbiotics may be used perioperatively to prevent POCD development and improve verbal memory performance in elderly patients receiving hip or knee arthroplasty.Clinical trial registrationwww.chictr.org.cn, identifier: ChiCTR2100045620

Analysis of solar seasonal storage in rural residences with Zhongyuan region as an example

A combined system of refrigeration and heating unit with seasonal solar thermal storage was presented in this paper. Based on the climate character of the Zhongyuan region, China, the system’s performance in rural residences was studied. A computational program was established based on the DEST software, the solar heat collecting capacity, heat collecting efficiency, and other parameters were analyzed. The results showed that the system can supply 76.28% heating load and 40.14% cooling load, when the total collector surface area equals to 40 m2 and heat collecting temperature is 80°C. The results will provide theoretical support for the system’s optimization

Study on Quality Change of Waxberry in Storage Period by Slow Freezing and Fast Freezing

In this study, the effects of slow freezing (−20 ℃) and quick freezing (−80 ℃) on the cell wall structure of waxberry fruits were investigated, and the changes of main nutrient quality components during storage were also studied. The moisture content and migration of waxberry fruits during storage were observed by low field NMR. The results showed that the cell wall morphology of quick-frozen waxberry fruits maintained well, and there were obvious gaps in the cross section of the cell wall of slow-frozen waxberry fruits. During the storage period of 25 days, the water content of fruit gradually decreased, but the range of water transfer of quick-frozen waxberry was small, and the total lateral relaxation time was larger than the relaxation time of slow-frozen waxberry, indicating that quick-frozen waxberry could effectively maintain fruit water activity. The free water signal value of quick-frozen waxberry decreased only by 18%, while the free water signal value of slow-frozen waxberry decreased by 47.75%, indicating that quick-frozen waxberry was beneficial to maintaining fruit water content. In addition, fruit nutrients decreased gradually, but the total sugar content, titratable acid content, total phenols and anthocyanins contents were 13.64 mg/g, 13.43 g/L, 15.43 mg/mL and 0.53 μmol/g, respectively, at the end of storage stage of quick-frozen waxberry. The retention rates of main nutritional indexes were higher than those of slow frozen waxberry. Therefore, quick-freezing can effectively delay the loss of nutrients in waxberry fruits