Improved design of the transmission mechanism of the of 4‑cylinder double‑acting Stirling engine

Four-cylinder U-shaped transmission mechanism design is closely related to operational stability, efficiency and life expectancy of Stirling engine system, as any deficiency of design of transmission mechanism may cause excessive reciprocating inertia force, centrifugal inertia force and counter-torque. Those intense forces and torques will transfer through the crankshaft bearings and the crankcase to supporting, resulting in the vibration of the Stirling engine and reducing the system operation stability and efficiency. According to features of four cylinder U-shaped drive mechanism, this paper built the counterweight theoretical model of transmission mechanism to obtain the values of counterweight and counter-balanced phase angle on crankshaft and output shaft. On this basis, dynamics simulation model of transmission mechanism can be established by multi-body dynamics simulation platform. Simulation results indicate that through certain improvement based on original design, the speed fluctuation coefficient of output shaft, left and right crankshafts is reduced by 19.2 %, 40.5 % and 37.4 % respectively; vibration displacement of the center of mass in output shaft is decreased by 19.5 %; average dynamic force and moment on engine body is diminished by 15.84 % and 20 % respectively; the weight of the flywheel can be declined by 50 % under steady working conditions. Above simulation results could verify the feasibility and effectiveness of improvement program aimed at dynamic balance. Meanwhile, this paper improves the power density of engine through the appropriate design of flywheel, striving to provide theoretical support for the design of transmission mechanism in Stirling engines

Improved design of the transmission mechanism of the of 4‑cylinder double‑acting Stirling engine

Four-cylinder U-shaped transmission mechanism design is closely related to operational stability, efficiency and life expectancy of Stirling engine system, as any deficiency of design of transmission mechanism may cause excessive reciprocating inertia force, centrifugal inertia force and counter-torque. Those intense forces and torques will transfer through the crankshaft bearings and the crankcase to supporting, resulting in the vibration of the Stirling engine and reducing the system operation stability and efficiency. According to features of four cylinder U-shaped drive mechanism, this paper built the counterweight theoretical model of transmission mechanism to obtain the values of counterweight and counter-balanced phase angle on crankshaft and output shaft. On this basis, dynamics simulation model of transmission mechanism can be established by multi-body dynamics simulation platform. Simulation results indicate that through certain improvement based on original design, the speed fluctuation coefficient of output shaft, left and right crankshafts is reduced by 19.2 %, 40.5 % and 37.4 % respectively; vibration displacement of the center of mass in output shaft is decreased by 19.5 %; average dynamic force and moment on engine body is diminished by 15.84 % and 20 % respectively; the weight of the flywheel can be declined by 50 % under steady working conditions. Above simulation results could verify the feasibility and effectiveness of improvement program aimed at dynamic balance. Meanwhile, this paper improves the power density of engine through the appropriate design of flywheel, striving to provide theoretical support for the design of transmission mechanism in Stirling engines

Effect of Hyperglycemia at Presentation on Outcomes in Acute Large Artery Occlusion Patients Treated With Solitaire Stent Thrombectomy

Background: Sporadic data showed hyperglycemia at presentation is associated with poor outcomes in patients with acute ischemic stroke (AIS) under mechanical thrombectomy (MT) treatment.Objective: This study aims to evaluate the relationship of admission hyperglycemia and outcomes in patients treated with solitaire stent thrombectomy.Methods: This multicenter prospective study registered patients with AIS due to anterior circulation large vessel occlusion (LVO) suitable for MT with Solitaire stent retriever. We analyzed the influence of admission hyperglycemia (≥7.8 mmol/L) and serum glucose on functional independence which is defined as modified Rankin Scale score (mRS) of 0–2, symptomatic intracranial hemorrhage (sICH) and several outcomes of interest using univariable and multiple logistic regression analysis.Results: This study involved 17 stroke centers across China and consecutively recruited 149 patients. Patients with hyperglycemia at presentation less frequently exhibited a functional independence at 3 months than patients without hyperglycemia (22.2 vs. 66.4%; odds ratio 0.75, 95% confidence interval 0.61–0.92; P = 0.005). Higher glucose levels were correlated with worse outcome (per 1 mmol/L increase in glucose: odds ratio for mRS score 0–2 at 3 months 0.17, 95% confidence interval 0.06–0.45; P < 0.001) at 3 months and sICH (per 1 mmol/L increase in glucose: odds ratio for sICH was 8.2, 95% confidence interval 1.13–29.57; P < 0.001) after thrombectomy.Conclusions: Higher admission serum glucose and hyperglycemia were independently correlated with lower functional independence at 3 months in patients treated with Solitaire stent thrombectomy of anterior circulation LVO. Higher admission serum glucose was also associated with sICH after thrombectomy

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Localization and identification of unknown target signal using oblique projection

Abstract The problem of source localization and waveform identification is the key of array signal processing. In this paper, an oblique projection-based localization and identification (OPLI) algorithm is proposed without known prior DOA or waveform information of the sources. The proposed OPLI is implemented iteratively. In each iteration, oblique projection is employed to separate the multiple incident signals into a series of single signal groups. After that, the procedure of waveform and DOA estimation for each single signal is implemented. Theoretical analysis and simulation result verify the performance and effectiveness of the proposed OPLI

Promotion of the Efficient Electrocatalytic Production of H₂O₂ by N,O- Co-Doped Porous Carbon

H2O2 generation via an electrochemical two-electron oxygen reduction (2e− ORR) is a potential candidate to replace the industrial anthraquinone process. In this study, porous carbon catalysts co-doped by nitrogen and oxygen are successfully synthesized by the pyrolysis and oxidation of a ZIF-67 precursor. The catalyst exhibits a selectivity of ~83.1% for 2e− ORR, with the electron-transferring number approaching 2.33, and generation rate of 2909.79 mmol g−1 h−1 at 0.36 V (vs. RHE) in KOH solution (0.1 M). The results prove that graphitic N and –COOH functional groups act as the catalytic centers for this reaction, and the two functional groups work together to greatly enhance the performance of 2e− ORR. In addition, the introduction of the –COOH functional group increases the hydrophilicity and the zeta potential of the carbon materials, which also promotes the 2e− ORR. The study provides a new understanding of the production of H2O2 by electrocatalytic oxygen reduction with MOF-derived carbon catalysts

Effects of Nitrate Addition on Rumen Fermentation, Bacterial Biodiversity and Abundance

This study examined changes of rumen fermentation, ruminal bacteria biodiversity and abundance caused by nitrate addition with Ion Torrent sequencing and real-time polymerase chain reaction. Three rumen-fistulated steers were fed diets supplemented with 0%, 1%, and 2% nitrate (dry matter %) in succession. Nitrate supplementation linearly increased total volatile fatty acids and acetate concentration obviously (p = 0.02; p = 0.02; p0.05) and beta biodiversity of ruminal bacteria were not affected by nitrate. Nitrate increased typical efficient cellulolytic bacteria species (Ruminococcus flavefaciens, Ruminococcus ablus, and Fibrobacter succinogenes) (p<0.01; p = 0.06; p = 0.02). Ruminobactr, Sphaerochaeta, CF231, and BF311 genus were increased by 1% nitrate. Campylobacter fetus, Selenomonas ruminantium, and Mannheimia succiniciproducens were core nitrate reducing bacteria in steers and their abundance increased linearly along with nitrate addition level (p<0.01; p = 0.02; p = 0.04). Potential nitrate reducers in the rumen, Campylobacter genus and Cyanobacteria phyla were significantly increased by nitrate (p<0.01; p = 0.01). To the best of our knowledge, this was the first detailed view of changes in ruminal microbiota by nitrate. This finding would provide useful information on nitrate utilization and nitrate reducer exploration in the rumen

Arbuscular mycorrhizal and dark septate endophyte colonization in Artemisia roots responds differently to environmental gradients in eastern and central China

Arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) are two types of root symbiotic fungi that enhance nutrient uptake by host plants and their resistance to biotic and abiotic stresses. However, it remains unclear whether AMF and DSE are synergistic or antagonistic in the presence of host plants to environmental gradients, especially on large geographical scales. To determine the relationships between AMF and DSE and their adaptability on a regional scale, we measured AMF and DSE colonization in the roots of 1023 plants of different species within the Artemisia genus collected from 81 sites across central and eastern China. We used general linear mixed models to analyze the relationships between colonization, and temperature and precipitation conditions. We found no significant correlation between AMF and DSE. The AMF colonization rate followed a significant longitudinal trend, but there was no latitudinal pattern. DSE colonization did not follow any geographical pattern. The AMF colonization rate was positively correlated with temperature and precipitation, whereas it was not significantly correlated with soil. There was no significant correlation between DSE colonization and climate or soil. Our results suggest that AMF and DSE play independent roles in the response of Artemisia to the regional environment. Therefore, studies on mycorrhizal symbiosis should discern the differential responses between AMF and DSE to climate and soil when evaluating the adaptability of the two types of symbiosis on large geographical scales. (c) 2021 Published by Elsevier B.V