| 3131. |
- Sui, Y., et al.
(författare)
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Mining urban sustainable performance : Spatio-temporal emission potential changes of urban transit buses in post-COVID-19 future
- 2020
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 280
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Tidskriftsartikel (refereegranskat)abstract
- Emission benefits of transit buses depend on ridership. Declines in ridership caused by COVID-19 leads uncertainty about the emission reduction capacity of buses. This paper provides a method framework for analyzing spatio-temporal emission patterns of buses in combination with real-time ridership and potential emission changes in the post-COVID-19 future. Based on GPS trajectory and Smart Card data of 2056 buses from 278 routes covering 1.5 million ridership in Qingdao, China, spatio-temporal emissions characteristics of buses are studied. 7589 taxis with 0.2 million passengers’ trips are used for acquiring private cars’ emissions to evaluate the emissions difference between buses and cars. Empirical results show that the average difference between buses and cars with 2 persons can reach up to 117 g/km-person during 7:00–8:59 and 115 g/km-person during 17:00–18:59. However, buses have various emission benefits around the city at different periods. A double increase in emissions during non-rush hours can be observed compared with rush hours. 224 online survey data are used to study the potential ridership reduction trend in post-COVID-19. Results show that 56.3% of respondents would decrease the usage of buses in the post-COVID-19 future. Based on this figure, our analysis shows that per kilometer-person emissions of buses are higher than cars during non-rush hours, however, still lower than cars during rush hours. We conclude that when ridership reduces by more than 40%, buses cannot be “greener” travel modal than cars as before. Finally, several feasible policies are suggested for this potential challenge. Our study provides convincing evidence for understanding the emission patterns of buses, to support better buses investment decisions and promotion on eco-friendly public transport service in the post-COVID-19 future.
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| 3132. |
- Sui, Y., et al.
(författare)
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Optimization of Slag Chemistry Toward Inclusion Control for 28CrMo47 Drill Pipe Steel Based on Viscosity and Equilibration Studies
- 2015
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Ingår i: Steel Research International. - : John Wiley & Sons. - 1611-3683 .- 1869-344X.
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Tidskriftsartikel (refereegranskat)abstract
- During the refining of 28CrMo47 drill pipe steel, it is found that the product often has internal defects and cracks. The present work is initiated with a view to examine if these problems could be solved by optimizing the slag chemistry of the refining slag. Three series of slags, namely, slag A (57.09%CaO-15.74%SiO2-16.35%Al2O3-5.35%MgO, original slag in the steel plant), slag B (55%CaO-21%SiO2-12%Al2O3-7%MgO-5%CaF2), and slag C (51%CaO-17%SiO2-25%Al2O3-7%MgO) are designed and their viscosities are measured. The effect of Al2O3 content on viscosity of the slag C is also investigated as part of the slag optimization. Slag-steel equilibrium experiments are subsequently carried out in order to understand the effect of the slag chemistry, especially the variation in the Al2O3 content in the same on the inclusions in drill pipe steel. It is concluded that both increasing Al2O3 content of the slag used in the refining unit in the plant and addition of CaF2 could decrease effectively the slag viscosity. Inclusions in steel equilibrated with slag C1, corresponding to 51%CaO-7%MgO-25%Al2O3-17SiO2, consisted mainly of low melting point CaO-Al2O3 complex, which did not have any negative effect on the steel quality.
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| 3133. |
- Sun, H., et al.
(författare)
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High-frequency oscillatory ventilation versus synchronized intermittent mandatory ventilation plus pressure support in preterm infants with severe respiratory distress syndrome
- 2014
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Ingår i: Respiratory care. - : Daedalus Enterprises. - 0020-1324 .- 1943-3654. ; 59:2, s. 159-169
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Mechanical ventilation and surfactants are the standard treatment of preterm respiratory distress syndrome (RDS). The effects of the primary ventilation model on bronchopulmonary dysplasia (BPD) and long-term neurodevelopment outcomes are controversial. The purpose of this study was to compare the efficacy and safety of high-frequency oscillatory ventilation (HFOV) and synchronized intermittent mandatory ventilation plus pressure support ventilation (SIMV-PSV) in preterm infants with severe RDS. METHODS: A total of 366 eligible preterm infants were randomly assigned to treatment with HFOV (n = 184) or SIMV-PSV (n = 182). Surfactant was applied if PaO2/FIO2 was < 200 mm Hg after 2 hours of ventilation. Primary outcomes were mortality or incidence of BPD. Secondary outcomes were duration of ventilation and hospitalization, surfactant requirements, pneumothorax, retinopathy of prematurity ≥ stage 2, and neurodevelopment at 18 months of corrected age. RESULTS: Survival and complete outcome data were available for 288 infants at 18 months of corrected age. The incidence of death or BPD was significantly higher in the SIMV-PSV group (P =.001). The duration of mechanical ventilation and hospitalization was shorter and the incidence of surfactant requirement and retinopathy of prematurity was lower in the HFOV group (P <.001, P =.002, P =.04, respectively). Moderate or severe neurological disability was less frequent in the HFOV group than in the SIMV-PSV group at 18 months (P =.03). The combination of HFOV and surfactant dramatically reduced negative outcomes in preterm infants with severe RDS. CONCLUSIONS: Initial ventilation with HFOV in preterm infants with severe RDS reduces the incidence of death and BPD, and improves long-term neurodevelopment outcomes. (ClinicalTrials.gov NCT01496508). © 2014 Daedalus Enterprises.
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| 3134. |
- Sun, H. Q., et al.
(författare)
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Characteristics of Respiratory Distress Syndrome in Infants of Different Gestational Ages
- 2013
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Ingår i: Lung. - : Springer Science and Business Media LLC. - 0341-2040 .- 1432-1750. ; 191:4, s. 425-433
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to compare the risk factors, clinical characteristics, and complications of respiratory distress syndrome (RDS) in infants delivered very preterm, late preterm, and term in order to help optimize the management of RDS in neonates. A retrospective study was conducted on neonates admitted to the NICU between January 2006 and December 2010. The enrolled infants with RDS were categorized as very preterm (< 32(0/7) weeks gestation), moderately preterm (32(0/7)-33(6/7) weeks), late preterm (34(0/7)-36(6/7) weeks), and term (37(0/7)-42(0/7) weeks). The rates, potential risk factors, clinical characteristics, and complications of RDS of these four groups were comparatively analyzed. There was an increasing trend in incidence of RDS among the NICU admissions annually. Caesarean section without labor was significantly associated with RDS in term and late preterm infants (P < 0.001). Rates of requirements for ventilator and pulmonary surfactant were similar in very preterm and term infants but significantly lower in late preterm infants (P < 0.001). The oxygenation index value was not substantially lower in late preterm and term infants compared to very preterm infants, and the arterial oxygenation efficiency was improved slowly (P < 0.001). Incidence of pneumonia and occurrence of pneumothorax were significantly higher in term infants (P < 0.001). Term infants with RDS showed an association of RDS with caesarean section without labor and lung infection. These infants also showed slower improvement of oxygenation after surfactant administration and mechanical ventilation, and they experienced a high rate of pneumothorax complication, which was also noticed in late preterm neonates.
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| 3135. |
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| 3136. |
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| 3137. |
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| 3138. |
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| 3139. |
- Sun, S. J., et al.
(författare)
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Modulating the prestrain history to optimize strength and ductility in CoCrFeMnNi high-entropy alloy
- 2019
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Ingår i: Scripta Materialia. - : Elsevier. - 1359-6462 .- 1872-8456. ; 163, s. 111-115
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Tidskriftsartikel (refereegranskat)abstract
- CoCrFeMnNi high-entropy alloy (HEA) exhibits excellent combination of strength and ductility, but low yield strength. In order to ameliorate the mechanical properties, prestrain was applied in this work. The HEA prestrained at 77 K possesses higher yield strength and uniform elongation than the HEA prestrained at 293 K, indicating that the trade-off relationship between strength and ductility can be broken by modulating the prestrain history. Furthermore, the yield point phenomenon was disappeared after prestrained at 77 K. This can be related to the density and distribution of dislocations as imposed in the prestrain process at 293 K and 77 K.
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| 3140. |
- Sun, W. Y., et al.
(författare)
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Northern Hemisphere Land Monsoon Precipitation Increased by the Green Sahara During Middle Holocene
- 2019
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Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 46:16, s. 9870-9879
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Tidskriftsartikel (refereegranskat)abstract
- Changes in land cover and dust emission may significantly influence the Northern Hemisphere land monsoon precipitation (NHLMP), but observations are too short to fully evaluate their impacts. The “Green Sahara” during the mid‐Holocene (6,000 years BP) provides an opportunity to unravel these mechanisms. Here we show that during the mid‐Holocene, most of the NHLMP changes revealed by proxy data are reproduced by the Earth System model results when the Saharan vegetation cover and dust reduction are taken into consideration. The simulated NHLMP significantly increases by 33.10% under the effect of the Green Sahara. The North African monsoon precipitation increases most significantly. Additionally, the Saharan vegetation (dust reduction under vegetated Sahara) alone remotely intensifies the Asian (North American) monsoon precipitation through large‐scale atmospheric circulation changes. These findings imply that future variations in land cover and dust emissions may appreciably influence the NHLMP.
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