| 1. |
- Hedström, Peter, et al.
(author)
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On the Three-Dimensional Microstructure of Martensite in Carbon Steels
- 2012
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In: Proceedings Of The 1st International Conference On 3D Materials Science. - Hoboken, NJ, USA : John Wiley & Sons. - 9781118470398 - 9781627489331 ; , s. 19-24
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Conference paper (peer-reviewed)abstract
- The mechanical properties of high-performance steels are often reliant on the hard martensitic structure. It can either be the sole constituent e. g. in tool steels, or it can be part of a multi-phase structure as e. g. in dual-phase steels. It is well-known that the morphology of martensite changes from lath to plate martensite with increasing carbon content. The transition from lath to plate is however less known and in particular the three-dimensional (3D) aspects in the mixed lath and plate region require more work. Here the current view of the 3D microstructure of martensite in carbon steels is briefly reviewed and complemented by serial sectioning experiments using a focused ion beam scanning electron microscope (FIB-SEM). The large martensite units in the Fe-1.2 mass% C steel investigated here are found to have one dominant growth direction, less transverse growth and very limited thickening. There is also evident transformation twinning parallel to the transverse direction. It is concluded that more 3D analysis is required to understand the 3D microstructure of martensite in the mixed lath and plate region and to verify the recently proposed 3D phase field models of martensite in steels.
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| 2. |
- Menya, Emmanuel, 1982-, et al.
(author)
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Assessment of pollution levels resulting from biomass gasification
- 2014
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In: Journal of Environmental Chemical Engineering. - : Elsevier BV. - 2213-3437. ; 2:3, s. 1228-1235
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Journal article (peer-reviewed)abstract
- In biomass gasification process the producer gas generated can be cleaned by water scrubbing. Some of the organic compounds generated are entrained together with other flue gas dust particles in to the cooling stream. The treatment/disposal of this waste stream remains a challenge because some of the compounds are toxic to humans and the environment. The objective of this study was to assess pollution levels resulting from organic constituents of flue gas filtration in a downdraft gasifier. The study involved assessment of the concentration of polycyclic aromatic hydrocarbons (PAHs) in the liquid effluence. The impacts on human health and environment are also discussed and recommendations on measures to minimize the pollution levels are provided. A downdraft gasifier fed with maize cobs was used and condensates were collected by cooling of producer gas. Samples were preserved in a cooler at about 2 degrees C for 24 h before analysis using a capillary gas chromatographer connected to a mass spectrometer (GCMS). The results were that concentrations of: naphthalene was 204.3 mg/m, benzene 17.92 mg/m(3), toluene 182.94 mg/m(3), ethylbenzene 202.43 mg/m(3), 1,2-dimethyl benzene 359.28 mg/m(3) and 1,3+1,4-dimethyl benzene 1016.18 mg/m(3). It was observed that the concentrations of naphthalene and xylene were considerably higher than the recommended permissible exposure limits (PELs) on both human health and the environment. On the other hand, the concentrations of benzene, toluene, and ethylbenzene were below the PEL. Generally this study indicated that the liquid effluent meets regulatory standards, but it would be interesting to carryout tests with different biomass fuel types which this study recommends.
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| 3. |
- Niskanen, A. K., et al.
(author)
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MHC variability supports dog domestication from a large number of wolves : high diversity in Asia
- 2013
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In: Heredity. - : Springer Science and Business Media LLC. - 0018-067X .- 1365-2540. ; 110:1, s. 80-85
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Journal article (peer-reviewed)abstract
- The process of dog domestication is still somewhat unresolved. Earlier studies indicate that domestic dogs from all over the world have a common origin in Asia. So far, major histocompatibility complex (MHC) diversity has not been studied in detail in Asian dogs, although high levels of genetic diversity are expected at the domestication locality. We sequenced the second exon of the canine MHC gene DLA-DRB1 from 128 Asian dogs and compared our data with a previously published large data set of MHC alleles, mostly from European dogs. Our results show that Asian dogs have a higher MHC diversity than European dogs. We also estimated that there is only a small probability that new alleles have arisen by mutation since domestication. Based on the assumption that all of the currently known 102 DLA-DRB1 alleles come from the founding wolf population, we simulated the number of founding wolf individuals. Our simulations indicate an effective population size of at least 500 founding wolves, suggesting that the founding wolf population was large or that backcrossing has taken place.
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| 4. |
- Ortiz-Marcos, Isabel, et al.
(author)
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TIME European Summer School : An Innovative International Educational Experience
- 2011
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In: International Journal of Engineering Education. - : Tempus Publications. - 0949-149X. ; 27:5, s. 924-932
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Journal article (peer-reviewed)abstract
- This paper presents an innovative experience that was developed by six European universities to teach a common course in an unconventional, remote way, to geographically-separate groups of students. The course is especially designed to enable engineering students to learn the basics of how the European social and sustainable model works, to acquire some basic cultural and religious awareness, and to stimulate transnational group discussions on such intercultural affairs. One overarching goal of this T.I.M.E. (Top International Managers for Europe) European Summer School (TESS) course is to identify some of the challenges that an academic collaboration organization like T.I.M.E. faces for future education, especially considering that the computer literate and highly web-based children who are born today will, with their expectations of ‘virtual 3D encounters’, be entering university by 2030. This web-based, social interaction experience has been developed over the last four years. This paper gives the results.
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| 5. |
- Vimaleswaran, Karani S, et al.
(author)
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Association of vitamin D status with arterial blood pressure and hypertension risk: a mendelian randomisation study.
- 2014
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In: The lancet. Diabetes & endocrinology. - 2213-8595 .- 2213-8587. ; 2:9, s. 719-29
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Journal article (peer-reviewed)abstract
- Background Low plasma 25-hydroxyvitamin D (25[OH]D) concentration is associated with high arterial blood pressure and hypertension risk, but whether this association is causal is unknown. We used a mendelian randomisation approach to test whether 25(OH)D concentration is causally associated with blood pressure and hypertension risk. Methods In this mendelian randomisation study, we generated an allele score (25[OH]D synthesis score) based on variants of genes that affect 25(OH)D synthesis or substrate availability (CYP2R1 and DHCR7), which we used as a proxy for 25(OH)D concentration. We meta-analysed data for up to 108173 individuals from 35 studies in the D-CarDia collaboration to investigate associations between the allele score and blood pressure measurements. We complemented these analyses with previously published summary statistics from the International Consortium on Blood Pressure (ICBP), the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and the Global Blood Pressure Genetics (Global BPGen) consortium. Findings In phenotypic analyses (up to n=49363), increased 25(OH)D concentration was associated with decreased systolic blood pressure (β per 10% increase, −0·12 mm Hg, 95% CI −0·20 to −0·04; p=0·003) and reduced odds of hypertension (odds ratio [OR] 0·98, 95% CI 0·97–0·99; p=0·0003), but not with decreased diastolic blood pressure (β per 10% increase, −0·02 mm Hg, −0·08 to 0·03; p=0·37). In meta-analyses in which we combined data from D-CarDia and the ICBP (n=146581, after exclusion of overlapping studies), each 25(OH)D-increasing allele of the synthesis score was associated with a change of −0·10 mm Hg in systolic blood pressure (−0·21 to −0·0001; p=0·0498) and a change of −0·08 mm Hg in diastolic blood pressure (−0·15 to −0·02; p=0·01). When D-CarDia and consortia data for hypertension were meta-analysed together (n=142255), the synthesis score was associated with a reduced odds of hypertension (OR per allele, 0·98, 0·96–0·99; p=0·001). In instrumental variable analysis, each 10% increase in genetically instrumented 25(OH)D concentration was associated with a change of −0·29 mm Hg in diastolic blood pressure (−0·52 to −0·07; p=0·01), a change of −0·37 mm Hg in systolic blood pressure (−0·73 to 0·003; p=0·052), and an 8·1% decreased odds of hypertension (OR 0·92, 0·87–0·97; p=0·002). Interpretation Increased plasma concentrations of 25(OH)D might reduce the risk of hypertension. This finding warrants further investigation in an independent, similarly powered study.
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