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To enhance the overall performance of recompression supercritical carbon dioxide- (sCO2-) based systems, two new double-effect absorption reheat power cycles (DARPC) were developed in this study. These methods are based on the typical absorption power cycle (APC). For the proposed sCO2/DARPC systems, a parametric analysis of the thermodynamic and economic performances, as well as additional parametric optimisations, were performed quantitatively. The results indicate that replacing the APC subsystem with DARPC subsystems can enhance the total function of the sCO2 system even further, owing to the increased H2O vapour created in the separator and the reheating process, which adds to the greater net power output. Furthermore, compared to the DARPC2 subsystem, the DARPC1 subsystem may produce more H2O vapour from the generator and separator, resulting in an increase in net output power. When compared to a single sCO2 power cycle, multiobjective optimisations showed that the sCO2/DARPC1 and sCO2/DARPC2 systems could increase the exergy efficiency by 12.95% and 11.51% and decrease the total product unit cost by 9.67% and 8.37%, respectively. Furthermore, the sCO2/DARPC1 and sCO2/DARPC2 systems can achieve improvements in exergy efficiency of 4.95% and 3.61% and a total product unit cost of 4.52% and 3.15%, respectively, compared with the sCO2/APC system. [ABSTRACT FROM AUTHOR]

An afterburner encounters two primary features: high incoming flow velocity and low oxygen concentration in the incoming airflow, which pose substantial challenges and contribute significantly to the deterioration of combustion performance. In order to research the influence of oxygen content on the dynamic combustion characteristics of the afterburner under various inlet velocities, the effect of oxygen content (14–23%) on the field structure of reacting bluff body flow, flame morphology, temperature pulsation, and pressure pulsation of the afterburner at different incoming flow velocities (0.1–0.2 Ma) was investigated in this study by using a large eddy simulation method. The results show that two different instability features, BVK instability and KH instability, are observed in the separated shear layer and wake, and are influenced by changes in the O2 mass fraction and Mach number. The oxygen content and velocity affected the oscillation amplitude of the downstream flow. As the O2 mass fraction decreases, the flame oscillation amplitude increases, the OH concentration in the combustion chamber decreases, and the flame temperature decreases. Additionally, the amplitude of the temperature pulsation in the bluff body flame was primarily influenced by the temperature intensity of the flame and BVK instability. Moreover, the pressure pulsation is predominantly affected by the dynamic characteristics of the flow field behind the bluff body. When the BVK instability dominated, the primary frequency of the pressure pulsation aligned with that of the temperature pulsation. Conversely, under the dominance of the KH instability, the temperature pulsation did not exhibit a distinct main frequency. At present, the influence of oxygen content and incoming flow rate on the combustion performance of the combustion chamber is not clear. The study of the effect of oxygen content on the combustion characteristics of the combustion chamber at different incoming flow rates provides a reference for improving the performance of the combustion chamber and enhancing the combustion stability. [ABSTRACT FROM AUTHOR]

As modern aeroengine combustors advance towards high temperatures, afterburners are inevitably affected by diminished oxygen content in incoming flows, thus affecting combustion efficiency, instability, and flammability limits. In this study, the dynamic combustion characteristics of V-shaped bluff body-stabilised diffusion flames were investigated using a large eddy simulation method with an oxygen mass fraction range of 14–23% and temperatures ranging from 900 to 1100 K. The results show the significant effects of oxygen content and inflow temperature on the flame/flow behaviours downstream of the bluff-body flame holder. In a separated shear layer, two distinct modes of flow/flame shedding are observed when varying the oxygen content and inflow temperature. The results show that BVK instability governs the far-field wake flow/flame features, whereas the oxygen concentration and temperature significantly affect their oscillation amplitudes. In addition, variations in the incoming oxygen content and temperature shift the axial position of the transition from KH instability to BVK instability. Finally, a spectral analysis is conducted to investigate the characteristics of pressure and heat release pulsations under different scenarios. This study highlights the importance of oxygen content on the combustion dynamics of bluff body-stabilised diffusion flames at various temperatures, which is essential for optimising combustion efficiency and stability in practical applications. [ABSTRACT FROM AUTHOR]

Background: The overall satisfaction of patients after total knee arthroplasty (TKA) is approximately 80%, and current studies have demonstrated that patients with depression may have lower patient satisfaction. The purpose of this study was to determine whether perioperative psychological intervention in patients with depression improves the clinical outcomes and patient satisfaction in patients undergoing TKA.Methods: Six hundred patients who underwent primary TKA from May 2016 to January 2018 were prospectively screened for eligibility. A preoperative psychological evaluation was conducted by a psychiatrist to evaluate each patient's psychological status. Patients who were diagnosed with depression were randomly divided into 2 groups: the intervention group (patients received psychological interventions that were administered by a psychiatrist at the first visit before surgery and from then on) and the control group (patients received routine TKA care without psychological interventions). The primary outcome was patient satisfaction at 6 months postoperatively. The secondary outcomes were patient satisfaction at 2 years postoperatively as well as the Hospital for Special Surgery (HSS) scores, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and range of motion at 6 months and 2 years postoperatively.Results: Fifty-three patients with depression were identified. Fifty-one patients were enrolled in the randomized controlled trial. Two patients were lost to follow-up at 6 months after surgery. Therefore, 49 patients (25 in the intervention group and 24 in the control group) remained in the final analysis. At 6 months postoperatively, statistical differences in patient satisfaction were identified between the 2 groups (88.0% in the intervention group compared with 62.5% in the control group; odds ratio = 4.40; 95% confidence interval, 1.02 to 18.99). There was a significant improvement in the Self-Rating Depression Scale (SDS) score (the reduction rate was 51.97% in the intervention group compared with 17.35% in the control group) and the Symptom Checklist 90 Revised (SCL-90-R) subscore for depression (the reduction rate was 44.66% in the intervention group compared with 15.73% in the control group). The clinical outcomes, including the WOMAC scores, the HSS scores, and maximal range of motion, in the intervention group had improved significantly more compared with those in the control group.Conclusions: Psychological interventions during the perioperative period can improve patient satisfaction in patients with depression who undergo TKA. Therefore, psychological intervention and management may be beneficial for patients with depression who are planning to undergo TKA.Level Of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Abstract: The oxygen storage capacity (OSC) of Ce0.67Zr0.33O2 catalysts were investigated with CO–He pulses at 500 °C and CO–O2 dynamic pulses at 300–700 °C after redox and hydrothermal treatments. BET, XRD, and EPR were used to study the effects of the pretreatment on the surface and bulk structures of the catalyst. The results show that during the CO–He pulses, migration of oxygen from the bulk to the surface becomes important. The rate of oxygen migration depends on the structure of the solid and the number of the oxygen vacancies in the lattice. The experiments with dynamic pulses of CO–O2 reveal that DOSC is closely related to the surface area of the samples of the same composition. However, at high temperatures, oxygen in the bulk also contributes to DOSC due to bulk-to-surface migration. A mechanism describing the reaction between the surface oxygen and CO and the oxygen migration process from the bulk to the surface is proposed. [Copyright &y& Elsevier]

Background: The overall satisfaction of patients after total knee arthroplasty (TKA) is approximately 80%, and current studies have demonstrated that patients with depression may have lower patient satisfaction. The purpose of this study was to determine whether perioperative psychological intervention in patients with depression improves the clinical outcomes and patient satisfaction in patients undergoing TKA., Methods: Six hundred patients who underwent primary TKA from May 2016 to January 2018 were prospectively screened for eligibility. A preoperative psychological evaluation was conducted by a psychiatrist to evaluate each patient's psychological status. Patients who were diagnosed with depression were randomly divided into 2 groups: the intervention group (patients received psychological interventions that were administered by a psychiatrist at the first visit before surgery and from then on) and the control group (patients received routine TKA care without psychological interventions). The primary outcome was patient satisfaction at 6 months postoperatively. The secondary outcomes were patient satisfaction at 2 years postoperatively as well as the Hospital for Special Surgery (HSS) scores, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and range of motion at 6 months and 2 years postoperatively., Results: Fifty-three patients with depression were identified. Fifty-one patients were enrolled in the randomized controlled trial. Two patients were lost to follow-up at 6 months after surgery. Therefore, 49 patients (25 in the intervention group and 24 in the control group) remained in the final analysis. At 6 months postoperatively, statistical differences in patient satisfaction were identified between the 2 groups (88.0% in the intervention group compared with 62.5% in the control group; odds ratio = 4.40; 95% confidence interval, 1.02 to 18.99). There was a significant improvement in the Self-Rating Depression Scale (SDS) score (the reduction rate was 51.97% in the intervention group compared with 17.35% in the control group) and the Symptom Checklist 90 Revised (SCL-90-R) subscore for depression (the reduction rate was 44.66% in the intervention group compared with 15.73% in the control group). The clinical outcomes, including the WOMAC scores, the HSS scores, and maximal range of motion, in the intervention group had improved significantly more compared with those in the control group., Conclusions: Psychological interventions during the perioperative period can improve patient satisfaction in patients with depression who undergo TKA. Therefore, psychological intervention and management may be beneficial for patients with depression who are planning to undergo TKA., Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: This study was fully funded by the Beijing Municipal Science & Technology Commission (project number Z151100003915107). The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/G236)., (Copyright © 2020 by The Journal of Bone and Joint Surgery, Incorporated.)