| 1. |
- Liu, Qiang, 1985-
(författare)
-
Control of Wear-Resistance Properties in Ti-added Hypereutectic High Chromium Cast Iron
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High chromium cast iron (HCCI) is considered as one of the most useful wear resistance materials and their usage are widely spread in industry. The wear resistance and mechanical properties of HCCI mainly depend on type, size, number, morphology of hard carbides and the matrix structure (γ or α). The Hypereutectic HCCI with large volume fractions of hard carbides is preferred to apply in wear applications. However, the coarser and larger primary M7C3 carbides will be precipitated during the solidification of the hypereutectic alloy and these will have a negative influence on the wear resistance.In this thesis, the Ti-added hypereutectic HCCI with a main composition of Fe-17mass%Cr-4mass%C is quantitatively studied based on the type, size distribution, composition and morphology of hard carbides and martensite units. A 11.2μm border size is suggested to classify the primary M7C3 carbides and eutectic M7C3 carbides. Thereafter, the change of the solidification structure and especially the refinement of carbides (M7C3 and TiC) size by changing the cooling rates and Ti addition is determined and discussed. Furthermore, the mechanical properties of hypereutectic HCCI related to the solidification structure are discussed.Mechanical properties of HCCI can normally be improved by a heat treatment process. The size distribution and the volume fraction of carbides (M7C3 and TiC) as well as the matrix structure (martensite) were examined by means of scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD). Especially for the matrix structure, EBSD is a useful tool to classify the fcc (γ) and bcc (α) phases. In conclusion, low holding temperatures close to the eutectic temperature and long holding times are the best heat treatment strategies in order to improve wear resistance and hardness of Ti-alloyed hypereutectic HCCI.
|
|
| 2. |
- López-Fauqued, M., et al.
(författare)
-
Safety profile of the adjuvanted recombinant zoster vaccine : Pooled analysis of two large randomised phase 3 trials
- 2019
-
Ingår i: Vaccine. - : Elsevier Ltd. - 0264-410X .- 1873-2518. ; 37:18, s. 2482-2493
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies. Methods: Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30 days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12 months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period. Results: Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race. Conclusions: No safety concerns arose, supporting the favorable benefit-risk profile of RZV. © 2019 GlaxoSmithKline Biologicals SA
|
|
| 3. |
- Muñoz-Medina, José Esteban, et al.
(författare)
-
Evolutionary analysis of the Chikungunya virus epidemic in Mexico reveals intra-host mutational hotspots in the E1 protein
- 2018
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:12
-
Tidskriftsartikel (refereegranskat)abstract
- The epidemic potential of Chikungunya virus (CHIKV) was recently made evident by its introduction and rapid expansion in the Caribbean and the Americas. We sought to gain a detailed understanding of the dynamics of the epidemic in Mexico, the country with the highest number of confirmed CHIKV cases in the Americas, and to characterise viral evolution at the population and intra-host level. Analysis of the spatiotemporal distribution of 2,739 diagnosed cases in Mexico from December 2014 to December 2015 showed a rapid nationwide expansion of the epidemic with focalisation in the South West of the country. We sequenced the envelope glyco-protein 1 gene (E1) from 25 patients using the Illumina MiSeq platform and report synonymous and non-synonymous consensus mutations. Bayesian phylogenetic analysis using 249 Asian lineage E1 sequences gave updated estimates of nucleotide substitution rates for E1 and time to most recent common ancestor of major lineages. The analysis indicates phylogenetically-related emergent Latin American clusters in South Western Mexico, Nicaragua and Honduras and transmission of American strains in the Pacific islands. Detailed analysis showed that intrahost changes in E1 mainly occurred in two variable regions (E1:189–220 and E1:349–358) in domains II and III, respectively, in residues involved in inter and intra-envelope spike interactions. At the population level, this study sheds light on the introduction and evolutionary dynamics of CHIKV in the Americas. At the intra-host level, this study identifies mutational hotspots of the E1 protein with implications for understanding the relationship between the CHIKV quasispecies, viral fitness and pathogenesis.
|
|
| 4. |
- Pechsiri, Joseph Santhi, et al.
(författare)
-
Comparative life cycle assessment of conventional and novel microalgae production systems and environmental impact mitigation in urban-industrial symbiosis
- 2023
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 854
-
Tidskriftsartikel (refereegranskat)abstract
- The versatility of microalgae biomass as candidates for various products and bioremediation needs motivates interests towards design and implementation of novel microalgae bioreactors. Conventional open-reactors are reliant on large quantities of sunlight and space while yields are constrained by outdoor environment conditions. Conversely, closed-reactor systems like bubble columns reduces these constrains on microalgae growth while occupying far less space at the expense of high energy demands, notably from lighting systems. A novel patented closed reactor design has recently been proposed that improves the bubble column concept with an efficient and effective lighting system. The present study uses Life Cycle Assessment approach to compare the environmental performance of conventional reactors and the proposed internally luminated novel closed reactor design, expressing impacts per kg biostimulant for the Scenedesmus almeriensis harvest from such units. All performance data was collected from a pilot facility in Almeria, Spain. Urban-industrial symbiosis scenarios are also portrayed in the study using wastewater and incinerator flue gas. Results show that under synthetic nutrient and carbon inputs in Spanish pilot operations, the cumulative energy demand for the novel photobioreactors is similar to conventional vertically-stacked horizon bioreactors but are substantially more demanding than conventional open reactors. However, when leveraging renewable energy sources and the photosynthesis process to consume wastestreams in urban-industrial symbiosis scenarios, the novel photobioreactor was able to achieve up to 80 % improvements in several impact categories e.g. eutrophication and climate change. Impact mitigation credits per kg dwt biomass across all energy scenarios in symbiosis amount to asymptotic to 1.8 kg CO(2)eq and asymptotic to 0.09 kg PO4 eq. This highlights that such closed and internally illuminated photobioreactors can be competitive with conventional reactors, and have potential to harness photosynthesis to reduce environmental burdens in an urban-industrial symbiosis setting. Possible economies of scale and the associated potential gains in efficiencies are further discussed.
|
|
| 5. |
|
|
| 6. |
- Tinoco, José, et al.
(författare)
-
Modeling the in-flight events during metal spray forming
- 2004
-
Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 365:1-2, s. 302-310
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, the in-flight events occurring during deposition over a rotating substrate were modeled. The calculations were performed by solving the momentum and enthalpy equations for the gas. A Lagrangian approach was used to obtain the trajectories and thermal history of the droplets. A modified heat capacity model was used to simulate the release of latent heat due to the solidification of the droplets. Turbulent particle dispersion was not considered. The results showed that the droplet temperature strongly depends on the droplet diameter and on its location in the spray since the relative velocity between the gas and the droplets varies largely depending on the location. An estimation of the state of the spray is presented in terms of mass and thermal averages. The results showed that the average fraction of solid obtained in the spray depends on the initial conditions, such as gas temperature and particle size distribution parameters.
|
|
| 7. |
- Tinoco, José, 1971-
(författare)
-
On the Spray Forming of Metals, the Formation of Porosity and the Heat Evolution during Solidification
- 2003
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the heat evolution duringsolidification and its relation to the formation of porosity.It intends to improve the current understanding of theformation of porosity in cast materials with special interestin nodular cast iron and the spray forming process. Twodifferent systems, a Fe-based alloy, Cast iron, and a Ni-basedalloy, Inconel 625, are examined. The effect on the heatevolution of the morphology and the processing parameters inspray forming are treated.An evaluation of the microstructural features, segregationbehavior and physical properties such as latent heat of fusionis performed byusing thermal analysis under cooling ratesranging from 0.1 to 104 K/s. In order to achieve this amodified differential thermal analysis (DTA) equipment, amirror furnace and levitation casting are used. Results arepresented in terms of the fraction of solidified, the coolingrate and the microstructure observed. The measured latent heatof fusion is not constant throughout the solidificationprocess. Variations in morphology and cooling rate affect therelease of the latent heat.A thermodynamic model is used to describe the experimentalobservations and to explain the formation of pores in nodularcast iron by taking into consideration the formation of latticedefects during the liquid/solid transformation. In this casethe formation of porosity is regarded as a consequence ofchanges in the volume fraction ratio graphite/ during thesolidification process.A numerical model of the spray forming process is developedby means of CFD modelling and compared with experimentalmeasurements performed in an industrial facility. Stagnationpressure measurements provided information about the gas flowvelocity and an analysis of the overspray powder providedinformation about the particle thermal history. Evaluation ofthe deposit was also performed. It is observed that the processconditions in spray forming promote non-equilibriumsolidification even though solidification at the deposit occursat a lower rate. In this case the porosity formed near theinterface substrate/deposit depends largely on the substratetemperature. The presence of certain reactive elements, such astitanium, affects the porosity levels in the rest of thedeposit.Keywords:Thermal Analysis, Nodular Cast Iron, Inconel625, CFD, Flow Assesment, Multiphase Flow, Spray Deposition,Microporosity, Superalloys
|
|
