Heat transfer augmentation of mixture ratio TiO2 to SiO2 in hybrid nanofluid / K.A. Hamid...[et al.]

The efficiency in heat transfer fluid for cooling systems can be improved with the use of hybrid nanofluid. The combination of two or more single nanoparticles in the hybrid nanofluid improve their thermo-physical properties, hence contribute in heat transfer performance. The experimental investigation on forced convection heat transfer of hybrid nanofluid have been carried out on the evaluation of heat transfer coefficient and Nusselt number. The designated working temperature was 30oC, tested for various volume percentage of TiO2 to SiO2. The experiment was conducted in a plain tube under constant heat flux at 7,955W/m2. The hybrid nanofluid was prepared at 1.0% volume concentration at three mixture ratios of TiO2 to SiO2. The range of average enhancement in the heat transfer coefficient and Nusselt number observed were 13.6-29.7% and 9.0-17.8%, respectively. The ratio of TiO2 to SiO2 at 20:80 showed the optimum ratio that can be used to obtain maximum enhancement in heat transfer coefficient and Nusselt number. The pressure drop of the hybrid nanofluid increased about double the base fluid for ratio 50:50. Due to the small increment in friction factor which was 1.03 times, the hybrid nanofluid are appropriate for application of cooling systems. It is recommended to use TiO2- SiO2 nanofluid at ratio 20:80 due to its significant enhancement in heat transfer but least increment in friction factor

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Experimental investigation of nanoparticle mixture ratios on TiO2–SiO2 nanofluids heat transfer performance under turbulent flow

The new class of fluids namely nanofluids are highly desirable in the enhancement of thermal properties. Various studies were carried out based on their greater thermal performance. The nanofluids are also beneficial in improving the heat transfer performance of devices or systems that require cooling operations. However, the performance of nanofluids with dispersion of two or more different nanoparticles is limited in the literature. Hence, the present study was carried out to investigate the heat transfer performance of TiO2–SiO2 nanofluids for various nanoparticle mixture ratios dispersed in a water/ethylene glycol (W/EG) mixture. The convection heat transfer experiment is conducted under turbulent region with Reynolds number from 3000 to 24,000. Five composite mixtures in volume percent of TiO2 and SiO2 nanoparticles are prepared with mixture ratios (TiO2:SiO2) of 20:80, 40:60, 50:50, 60:40 and 80:20 for a constant volume concentration of 1.0%. The heat transfer performance and friction factor were evaluated for the bulk temperatures of 30, 50 and 70 °C. High performance was seen at a 40:60 mixture ratio with heat transfer enhancement of 35.32% at 70 °C temperature. The mixture ratio of 50:50 showed the least enhancement of 9.02% in heat transfer coefficient for a working temperature of 30 °C. Furthermore, the friction factor of the nanofluids is practically negligible due to the small increment. As a conclusion, the nanoparticle mixture ratios of TiO2–SiO2 nanofluids contributed to the overall performance of heat transfer. It was recommended to use 20:80 and 40:60 mixture ratios of TiO2–SiO2 nanofluids in heat transfer systems

Combining SPF and source routing for an efficient probing solution in IPv6 topology discovery

Source routing and routing protocols are two well known methods used to discover network connectivity within IPv6 networks. The source routing discovery method faces the challenge of probing space explosion phenomenon which generates a large volume of traffic and takes a significant amount of time to discover the entire network. On the other hand, a routing protocol based approach, such as OSPFv3, discovers the network connectivity but only discovers the prefix portion of the IPv6 addresses. To address these issues, this paper proposes an efficient probing space reduction algorithm by combining source routing and OSPFv3 for the purpose of ne

Surgery After Primary Dexamethasone Treatment for Patients with Chronic Subdural Hematoma—A Retrospective Study

Background: We aimed to quantify the need for additional surgery in patients with chronic subdural hematoma (CSDH) primarily treated with dexamethasone and to identify patient characteristics associated with additional surgery. Methods: Data were retrospectively collected from 283 patients with CSDH, primarily treated with dexamethasone, in 3 hospitals from 2008 to 2018. Primary outcome was the need for additional surgery. The association between baseline characteristics and additional surgery was analyzed with univariable and multivariable logistic regression analysis and presented as adjusted odds ratios (aOR). Results: In total, 283 patients with CSDH were included: 146 patients (51.6%) received 1 dexamethasone course (DXM group), 30 patients (10.6%) received 2 dexamethasone courses (DXM-DXM group), and 107 patients (37.8%) received additional surgery (DXM-SURG group). Patients who underwent surgery more often had a Markwalder Grading Scale of 2 (as compared with 1, aOR 2.05; 95% confidence interval [CI] 0.90–4.65), used statins (aOR 2.09; 95% CI 1.01–4.33), had a larger midline shift (aOR 1.10 per mm; 95% CI 1.01–1.21) and had larger hematoma thickness (aOR 1.16 per mm; 95% CI 1.09–1.23), had a bilateral hematoma (aOR 1.85; 95% CI 0.90–3.79), and had a separated hematoma (as compared with homogeneous, aOR 1.77; 95% CI 0.72–4.38). Antithrombotics (aOR 0.45; 95% CI 0.21–0.95) and trabecular hematoma (as compared with homogeneous, aOR 0.31; 95% CI 0.12–0.77) were associated with a lower likelihood of surgery. Conclusions: More than one-third of patients with CSDH primarily treated with dexamethasone received additional surgery. These patients were more severely affected amongst others with larger hematomas