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High consumption of electricity represents an economic and social problem in warm places, caused by the massive use of cooling machines. Absorption systems are a sustainable method for air conditioning applications. However, environmental conditions should be analyzed to avoid crystallization problems of the working mixture. This article presents a thermal analysis of a solar absorption cooling system in dynamic conditions using NH 3 -H 2 O, H 2 O-LiBr, NH 3 -NaSCN, NH 3 -LiNO 3 , and H 2 O-LiCl working mixtures using Equation Engineering Solver (EES) and TRaNsient SYstem Simulation (TRNSYS) software. A solar collector area of 42.5 m 2 was selected to carry out the thermal analysis. The results showed that H 2 O-LiCl obtained the maximum solar (0.67) and minimum heating (0.33) fraction. However, it obtained the maximum lost heat fraction (0.12), in spite of obtaining the best coefficient of performance (COP) among the other working mixtures, due mainly to a crystallization problem. The gain fraction (GF) parameter was used to select the adequate solar collector number for each working mixture. NH 3 -LiNO 3 and NH 3 -H 2 O obtained the highest GF (up 6), and both obtained the maximum solar (0.91) and minimum heating (0.09) fraction, respectively, using 88.8 and 100.4 m 2 of solar collector area, respectively.

Annually, millions of tons of foods are generated with the purpose to feed the growing world population. One particular eatable is orange, the production of which in 2018 was 75.54 Mt. One way to valorize the orange residue is to produce bioethanol by fermenting the reducing sugars generated from orange peel. Hence, the objective of the present work was to determine the experimental conditions to obtain the maximum yield of reducing sugars from orange peel using a diluted acid hydrolysis process. A proximate and chemical analysis of the orange peel were conducted. For the hydrolysis, two factorial designs were prepared to measure the glucose and fructose concentration with the 3,5-DNS acid method and UV-Visible spectroscopy. The factors were acid concentration, temperature and hydrolysis time. After the hydrolysis, the orange peel samples were subjected to an elemental SEM-EDS analysis. The results for the orange peel were 73.530% of moisture, 99.261% of volatiles, 0.052% of ash, 0.687% of fixed carbon, 19.801% of lignin, 69.096% of cellulose and 9.015% of hemicellulose. The highest concentration of glucose and fructose were 24.585 and 9.709 g/L, respectively. The results highlight that sugar production is increased by decreasing the acid concentration.

BACKGROUND: Laboratory studies suggest applying positive pressure without endotracheal suction during cuff deflation and extubation. Although some studies reported better physiological outcomes (e.g. arterial blood gases) with this technique, the safety of positive pressure extubation technique has not been well studied. The aim of this study was to determine the safety of the positive-pressure extubation technique compared with the traditional extubation technique in terms of incidence of complications. METHODS: Adult subjects who were critically ill and on invasive mechanical ventilation who met extubation criteria were included. The subjects were randomly assigned to positive-pressure extubation (n ‫؍‬ 120) or to traditional extubation (n ‫؍‬ 120). Sequential tests for noninferiority and, when appropriate, for superiority were performed. Positive pressure was considered noninferior if the upper limit of the CI for the absolute risk difference did not exceed a threshold of 15% in favor of the traditional group, both in per protocol and intentionto-treat analyses. A P value of <.05 was considered significant. RESULTS: A total of 236 subjects were included in the primary analysis (per protocol) (119 in the positive-pressure group and 117 in the traditional group). The incidence of overall major and minor complications, pneumonia, extubation failure, and reintubation was lower in the positive-pressure group than in the traditional group, with statistical significance for noninferiority both in the per protocol (P < .001) and intention-to-treat (P < .001) analyses. The lower incidence of major complications found in the positive-pressure group reached statistical significance for the superiority comparison, both in per protocol (P ‫؍‬ .03) and intention-to-treat (P ‫؍‬ .049) analyses. No statistically significant differences were found in the superiority comparison for overall complications, minor complications, pneumonia, extubation failure, and reintubation. CONCLUSIONS: Positive pressure was safe and noninferior to traditional extubation methods. Furthermore, positive pressure has shown to be superior in terms of a lower incidence of major complications. (ClinicalTrials.gov registration NCT03174509.

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