| 31. |
- Sun, Yi-lin, et al.
(författare)
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Detangling the impacts of age, residential locations and household lifecycle in car usage and ownership in the Osaka metropolitan area, Japan
- 2014
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Ingår i: Zhejiang University. Journal. Science A: Applied Physics & Engineering. - 1673-565X. ; 15:7, s. 517-528
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Tidskriftsartikel (refereegranskat)abstract
- Using large cross-sectional datasets that were collected in the Osaka metropolitan area (OMA), Japan, this study systematically analyzes the structural changes in car ownership and usage in the OMA from 1970 to 2000. A simultaneous equations model system is developed for individuals that considers age, household lifecycle stage, built environment of the household location, car ownership levels, proportion of car trips on a given day, and total car travel duration. The estimation results show that private car ownership and car usage for the residents in OMA have expanded over time. Each residential area, each lifecycle stage, and each age group has their own unique characteristics of car ownership and car usage. The results further indicate that this expansion is largely due to changes in their structural relationships, while the changes in demographic factors play a relatively small and contradictory role.
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| 32. |
- Wang, Faming, et al.
(författare)
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Coastal blue carbon in China as a nature-based solution toward carbon neutrality
- 2023
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Ingår i: INNOVATION. - 2666-6758. ; 4:5
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Forskningsöversikt (refereegranskat)abstract
- To achieve the Paris Agreement, China pledged to become "Carbon Neutral" by the 2060s. In addition to massive decarbonization, this would require significant changes in ecosystems toward negative CO2 emissions. The ability of coastal blue carbon ecosystems (BCEs), including mangrove, salt marsh, and seagrass meadows, to sequester large amounts of CO2 makes their conservation and restoration an important "nature-based solution (NbS)" for climate adaptation and mitigation. In this review, we examine how BCEs in China can contribute to climate mitigation. On the national scale, the BCEs in China store up to 118 Tg C across a total area of 1,440,377 ha, including over 75% as unvegetated tidal flats. The annual sedimental C burial of these BCEs reaches up to 2.06 Tg C year(-1) , of which most occurs in salt marshes and tidal flats. The lateral C flux of mangroves and salt marshes contributes to 1.17 Tg C year(-1) along the Chinese coastline. Conservation and restoration of BCEs benefit climate change mitigation and provide other ecological services with a value of $32,000 ha(-1) year(-1). The potential practices and technologies that can be implemented in China to improve BCE C sequestration, including their constraints and feasibility, are also outlined. Future directions are suggested to improve blue carbon estimates on aerial extent, carbon stocks, sequestration, and mitigation potential. Restoring and preserving BCEs would be a cost-effective step to achieve Carbon Neutral by 2060 in China despite various barriers that should be removed.
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| 33. |
- Wang, Wei, et al.
(författare)
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Thermodynamic constitution of the Al-Cu-Ni system modeled by CALPHAD and ab initio methodology for designing high entropy alloys
- 2019
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Ingår i: Calphad. - : Elsevier. - 0364-5916 .- 1873-2984. ; 65, s. 346-369
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Tidskriftsartikel (refereegranskat)abstract
- The Al-Cu-Ni system has been thermodynamically assessed over the whole composition and temperature range based on a critical literature review. The L1(2) and B2 phases, in conjunction with their disordered counterparts, are described using partitioning models. Ab initio calculations were performed to support the assessment of these phases. A set of self-consistent thermodynamic parameters for describing the Gibbs energy of individual phases was obtained. The assessment was validated by comparing various calculations such as invariant reaction equilibria, thermochemical properties, isothermal and isoplethal sections with all available experimental data. The Al-Cu-Ni ternary is a vital subsystem of many high entropy alloys (HEAs), which can probably be attributed to the existence of stable ordered and disordered FCC and BCC structures. In near-equiatomic compositions of this ternary system, the phase formation and equilibrium and non-equilibrium solidification curves were calculated using the present thermodynamic description. The phase competitions and their impacts on the design of HEM are discussed, e.g. the relative stability of the disordered FCC and BCC for dual-phase HEAs, and the equilibria between disordered FCC_A1 and ordered B2 phases for ductile high strength HEM.
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| 34. |
- Wieduwilt, Matthew J., et al.
(författare)
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Haploidentical vs sibling, unrelated, or cord blood hematopoietic cell transplantation for acute lymphoblastic leukemia
- 2022
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Ingår i: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 6:1, s. 339-357
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Tidskriftsartikel (refereegranskat)abstract
- The role of haploidentical hematopoietic cell transplantation (HCT) using posttransplant cyclophosphamide (PTCy) for acute lymphoblastic leukemia (ALL) is being defined. We performed a retrospective, multivariable analysis comparing outcomes of HCT approaches by donor for adults with ALL in remission. The primary objective was to compare overall survival (OS) among haploidentical HCTs using PTCy and HLA-matched sibling donor (MSD), 8/8 HLAmatched unrelated donor (MUD), 7 /8 HLA-MUD, or umbilical cord blood (UCB) HCT. Comparing haploidentical HCT to MSD HCT, we found that OS, leukemia-free survival (LFS), nonrelapse mortality (NRM), relapse, and acute graft-versus-host disease (aGVHD) were not different but chronic GVHD (cGVHD) was higher in MSD HCT. Compared with MUD HCT, OS, LFS, and relapse were not different, but MUD HCT had increased NRM (hazard ratio [HR], 1.42; P = .02), grade 3 to 4 aGVHD (HR, 1.59; P = .005), and cGVHD. Compared with 7/8 UD HCT, LFS and relapse were not different, but 7/8 UD HCT had worse OS (HR, 1.38; P = .01) and increased NRM (HR, 2.13; P <_ .001), grade 3 to 4 aGVHD (HR, 1.86; P = .003), and cGVHD (HR, 1.72; P <_ .001). Compared with UCB HCT, late OS, late LFS, relapse, and cGVHD were not different but UCB HCT had worse early OS (<_18 months; HR, 1.93; P < .001), worse early LFS (HR, 1.40; P = .007) and increased incidences of NRM (HR, 2.08; P < .001) and grade 3 to 4 aGVHD (HR, 1.97; P < .001). Haploidentical HCT using PTCy showed no difference in survival but less GVHD compared with traditional MSD and MUD HCT and is the preferred alternative donor HCT option for adults with ALL in complete remission.
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| 35. |
- Xu, Min, et al.
(författare)
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Ototoxicity on cochlear nucleus neurons following systemic application of gentamicin
- 2009
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 129:7, s. 745-748
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Tidskriftsartikel (refereegranskat)abstract
- Conclusion. The gentamicin-induced pathological alteration in the cochlear nucleus is not exclusively a secondary consequence of the damage in the cochlea. Instead, the toxic effect of gentamicin on the cochlear nucleus may occur simultaneously or even earlier than that on the cochlea. Objectives. To investigate the pathological alteration of cochlear nucleus neurons in guinea pigs following systemic application of gentamicin. Materials and methods. Guinea pigs were injected with gentamicin for I day, 3 days, I week, 2 weeks, and 3 weeks, respectively. In gentamicin-treated animals, the hearing function was evaluated by measuring the auditory brainstem response (ABR). The number and cross-sectional area of substance P-positive neurons in the cochlear nucleus were also measured. Results. The threshold of ABR and the number of substance P-positive neurons in the cochlear nucleus were significantly increased after I week and 3 days of injection of gentamicin, respectively. The cross-sectional area of substance P-positive neurons in the cochlear nucleus was significantly reduced after 1-day injection of gentamicin.
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| 36. |
- Yang, Mei Jie, et al.
(författare)
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Expression and activity of critical digestive enzymes during early larval development of the veined rapa whelk, Rapana venosa (Valenciennes, 1846)
- 2020
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 519
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Tidskriftsartikel (refereegranskat)abstract
- Metamorphosis is a vital developmental event in the life cycle of molluscs and involves extensive morphological and physiological changes. Remodeling of the digestive system is suggested to occur anticipatorily to enable the larva to shift its diet (from filter feeding on microalgae to feeding on small bivalves) after metamorphosis. Changes in the profiles and activities of digestive enzymes, the main executors of digestion, can reflect substantial remodeling of the digestive system. Artificial aquaculture of Rapana venosa, an important commercial shellfish in China, has been hampered because the transition of its food habit during metamorphosis makes determining the timing and dose for bait regulation difficult. In the present study, full-length cDNA sequences encoding cellulase and trypsin were characterized, and cellulase and trypsin mRNA expression levels were analyzed. Additionally, patterns in the activities of six digestive enzymes, including trypsin and cellulase, were investigated throughout the early developmental stage of R. venosa. In the present study, the full-length cDNA of the cellulase gene, comprising 2,086 bp, was found to contain a 1,719-bp open reading frame encoding 572 amino acids, and the full-length cDNA of the trypsin gene was found to be 1,587 bp in length and contained an 855-bp open reading frame encoding 284 amino acids. Quantitative real-time PCR showed that the cellulase levels in R. venosa increased beginning at the early intramembrane veliger stage, whereas cellulase activity was significantly increased in the one-spiral whorl stage. The mRNA expression and activity of trypsin were greatly increased in the juvenile stage (postlarva), whereas those of cellulase were decreased during this stage, which indicated functional changes in the digestive system during larval food habit transition. Our results showed that remodeling of the digestive system occurs prior to metamorphosis and suggest that animal bait should be provided as early as possible to R. venosa in the four-spiral whorl stage to meet its nutritional requirements for the development of its digestive system and to ensure successful metamorphosis of competent larvae.
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| 37. |
- Yang, Yi, et al.
(författare)
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Facile Hydrothermal Synthesis of Highly Efficient and Durable Ternary Ptpdcu Electrocatalysts For Methanol Oxidation Reaction : Iodide Matters
- 2022
-
Ingår i: Social Science Research Network SSRN. - : Elsevier BV. - 1556-5068.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Precious metal Pt-based electrocatalysts have been widely used in methanol catalytic oxidation of anodes in direct methanol fuel cells (DMFCs). However, it has been still the challenge to decrease their cost and improve their efficiency and stability. In this study, ternary PtPdCu nanocatalysts were synthesized through a facile one-step hydrothermal synthesis method. When KI was present with a suitable amount in the synthesis, PtPdCu nanospheres with surface embedded CuI clusters (CuI/PtPdCu) were obtained. While without using KI, the prepared PtPdCu catalysts show a distinct hollow structure (h-PtPtCu). CuI/PtPdCu displays the highest specific activity with a 4 times enhancement than commercial Pt/C for methanol oxidation reaction (MOR) in an alkaline medium. The superior activity can attribute to the two aspects: i) Electronic effect originated from the highly alloyed PtPdCu. ii) synergetic effect due to the surface inlayed CuI clusters which can promote the CO intermediate removal. Furthermore, owing to the stable Pt-Pd-rich surface and its special linked hollow structure, h-PtPtCu catalyst exhibits the best durability with only a 3.6 % decay in specific activity.
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| 38. |
- Yuan, Kang, 1987-
(författare)
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Oxidation and Corrosion of New MCrAlX Coatings : Modelling and Experiments
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- MCrAlY coatings (“M” for Ni and/or Co) are widely used for the protection of superalloy components operated at high temperatures such as in the hot sections of gas turbines. The exposure to high temperature can cause coating degradation due to oxidation or hot corrosion at the coating surface. Microstructures in the coating and the coating life are affected also by the diffusion of alloying elements through the coating-superalloy interface. This PhD project, by applying thermodynamic modelling and experimental tests, investigates the oxidation and hot corrosion behavior of new MCrAlX coatings, in which X, referring to minor elements, is used to highlight the functions of such elements.In order to understand and predict the coating degradation progress during thermal exposure, an oxidation-diffusion model has been established for MCrAlX coating-superalloy systems, which integrates the oxidation of aluminum at coating surface, diffusion of alloying elements, and the diffusion-blocking effect in the materials. The predicted chemical composition profile and microstructure agreed well with experimental results in a CoNiCrAlYSiTa-Inconel 792 system. The model was further applied in several coating-superalloy systems to study the influence of coating composition, superalloy composition and temperature on the evolution of microstructure in the coating and the coating life. The results have demonstrated the potential of the model in designing new durable MCrAlX coatings. In addition to the applications in coating-superalloy systems, the model was also adapted for studying the microstructural development in a superalloy in which internal oxidation and nitridation occurred in an oxidation process.The oxidation behavior of some HVOF MCrAlX coatings was studied by thermal exposure at different temperatures (900, 1000, 1100 °C). Different spinels formed above the alumina scale, depending on the oxidation temperature. The minor alloying elements, Ru and Ir, had no direct influence on the oxidation behavior but may affect the phase stability in the coating.MCrAlX coatings were also tested in 48-hour cycles at 900 °C in different hot corrosion environments containing sulphates and/or SO2. The results showed that the coating performance was dependent on coating quality, concentration of Al and Cr in the coating, and the hot corrosion condition. It was also found that the addition of SO2 in the environment may not necessarily be bad for hot corrosion resistance of some MCrAlY coatings.
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| 39. |
- Yuan, Kang, et al.
(författare)
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Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation
- 2015
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 261, s. 86-101
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Tidskriftsartikel (refereegranskat)abstract
- MCrAlY coatings are widely used to protect superalloys against oxidation and corrosion at high temperature in gas turbine engines. To design a durable MCrAlY coating, the elemental behaviour in coating-superalloy couples needs to be better understood. After oxidation tests in temperature range between 900 °C to 1100 °C, the microstructural development in the samples were analysed. The investigation was mainly focused on the microstructures at the coating surface or in areas near the coating-superalloy interface. Some interdiffusion simulations were also done to model the diffusion behaviour of alloying elements in different coatingsuperalloy couples. The results showed that both oxidation at the coatings’ surfaces and the elements’ diffusion inside of the materials were temperature- and chemical-composition dependent. The behaviour of some minor elements like Y, Hf, Ru and Ir in the oxidation processes was particularly studied by tracking their position and composition in the materials.
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| 40. |
- Yuan, Kang
(författare)
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Thermal and Mechanical Behaviors of High Temperature Coatings
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With superior oxidation and corrosion resistance, metallic coatings (i.e. diffusion coatings and MCrAlX coatings) are widely used to protect hot components made of superalloys in turbine engines. Two issues are critically important for the coating at high temperatures: thermal property related to oxidation/corrosion behavior and microstructure stability, and mechanical properties (e.g. creep and fatigue). The aim of this project is to develop better understanding of the thermal and mechanical behaviors of metallic coatings on superalloys and to improve the accuracy of prediction of their lifetime by thermodynamic modeling. The present work includes an investigation on the oxidation behavior of MCrAlX coating with a new lifetimeprediction model and a study on the influence of diffusion coatings on creep and fatigue behaviors of the superalloy IN792.Experiments on isothermal and thermal cycling oxidation were designed to investigate the oxidation behavior of a HVOF CoNiCrAlYSi coating on superalloy IN792. It is found that the oxidation behaviors of the coating are related to its thermodynamic property. A diffusion model has been established using the homogenization models in the DICTRA software and taking into consideration of the influence of surface oxidation, coating-substrate interdiffusion and diffusion blocking effect caused by internal voids and oxides. The simulation results show an improved accuracy of lifetime prediction by introducing the diffusion blocking effect.Microstructural evolution during creep process at high temperatures was studied in different diffusion coatings (NiAl and PtAl). It is found that the inward diffusion of aluminum controls the thickening rate of the diffusion coatings. The developed coatings displayed two types of mechanical behavior - being easily plasticized or cracked - dependent on temperature and type of coating, and therefore could be considered as non-load carrying material during creep test. The influence of cracking of PtAl coating on the high-cycle fatigue (HCF) behavior of the IN792 was also investigated. The results show that precracking of the coating prior to the fatigue test has little influence on the fatigue limit of specimens with thin coating (50 μm) but lowers the fatigue limit of specimens with thick coating (70 μm). The through-coating crack has enough mobility to penetrate into the substrate and causes fatigue failure only when the driving force for crack propagation is increased above a critical value due to a higher applied stress or a larger crack length (thicker coating).
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