| 33281. |
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| 33282. |
- Fagerström, Jonathan, 1984-
(författare)
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Fine particle emissions and slag formation in fixed-bed biomass combustion : aspects of fuel engineering
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is a consensus worldwide that the share of renewable energy sources should be increased to mitigate climate change. The strive to increase the renewable energy fraction can partly be met by an increased utilization of different biomass feedstocks. Many of the "new" feedstocks puts stress on certain challenges such as air pollution emissions and operation stability of the combustion process. The overall objective was to investigate, evaluate, and explain the effects of fuel design and combustion control - fuel engineering - as primary measures for control of slag formation, deposit formation, and fine particle emissions during biomass combustion in small and medium scale fixed-bed appliances. The work in this thesis can be outlined as having two main focus areas, one more applied regarding fuel engineering measures and one more fundamental regarding the time-resolved release of ash forming elements, with particular focus on potassium.The overall conclusion related to the abatement of particle emissions and slag formation, is that the release of fine particle and deposit forming matter can be controlled simultaneously as the slag formation during fixed-bed biomass combustion. The methodology is in this perspective denoted “fuel engineering” and is based on a combined approach including both fuel design and process control measures. The studies on time-resolved potassium release showed that a Macro-TG reactor with single pellet experiments was a valuable tool for studying ash transformation along the fuel conversion. The combination of dedicated release determinations based on accurate mass balance considerations and ICP analysis, with phase composition characterization by XRD, is important for the understanding of potassium release in general and time-resolved data in particular. For wood, the results presented in this work supports the potassium release mechanism from "char-K" but questions the previously suggested release mechanism from decomposition of K-carbonates. For straw, the present data support the idea that the major part of the potassium release is attributed to volatilization of KCl. To further explore the detailed mechanisms, the novel approach developed and applied in this work should be complemented with other experimental and analytical techniques.The research in this thesis has explored some of the challenges related to the combined phenomena of fuel conversion and ash transformation during thermochemical conversion of biomass, and has contributed with novel methods and approaches that have gained new knowledge to be used for the development of more effective bioenergy systems.
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| 33283. |
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| 33284. |
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| 33285. |
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| 33286. |
- Fagerström, Lisbeth, et al.
(författare)
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Sense of security among people aged 65 and 75 : external and inner sources of security
- 2011
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Ingår i: Journal of Advanced Nursing. - : Blackwell Publishing Ltd. - 0309-2402 .- 1365-2648. ; 67:6, s. 1305-1316
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Tidskriftsartikel (refereegranskat)abstract
- Aim. This paper is a report of a study exploring possible external and inner sources of the sense of security felt by older people aged 65 and 75. Background. The concept of ‘security’ has been parsimoniously defined and explored, especially as pertains to older people, and previous research has primarily focused on risks in relation to individuals’ declining health and functional ability. Methods. In 2005, population-based cross-sectional surveys were carried out in 15 municipalities in Västerbotten, Sweden and 18 municipalities in Ostrobothnia, Finland. A 15-page questionnaire (84 questions) was distributed, with the final total response rate reaching 68·4% (n = 3370): 1825 Swedish-speaking Swedes, 926 Swedish-speaking Finns and 621 Finnish-speaking Finns. The statistical analysis was three-stage, including nominal stepwise regressions. Results. Older people who indicate that they are ‘very secure’ are more likely to consider life meaningful and are able to master various life crises. Moreover, they possess confidence in economic institutions and are more likely to feel economically secure. Weak trust in family and friends or neighbours and decreased functional ability seem to indicate a subjective feeling of ‘insecurity’. Conclusion. Caregivers in health care should focus more on supporting older persons’ meaningfulness in life and how their feelings of security can be strengthened by trusting relationships and activities. In nursing, there should be more focus on developing knowledge of inner health resources, including positive life orientation and meaningfulness in life.
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| 33287. |
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| 33288. |
- Fages, Anne, et al.
(författare)
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Investigating sources of variability in metabolomic data in the EPIC study : the Principal Component Partial R-square (PC-PR2) method
- 2014
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Ingår i: Metabolomics. - : Springer. - 1573-3882 .- 1573-3890. ; 10:6, s. 1074-1083
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Tidskriftsartikel (refereegranskat)abstract
- The key goal of metabolomic studies is to identify relevant individual biomarkers or composite metabolic patterns associated with particular disease status or patho-physiological conditions. There are currently very few approaches to evaluate the variability of metabolomic data in terms of characteristics of individuals or aspects pertaining to technical processing. To address this issue, a method was developed to identify and quantify the contribution of relevant sources of variation in metabolomic data prior to investigation of etiological hypotheses. The Principal Component Partial R-square (PC-PR2) method combines features of principal component and of multivariable linear regression analyses. Within the European Prospective Investigation into Cancer and nutrition (EPIC), metabolic profiles were determined by H-1 NMR analysis on 807 serum samples originating from a nested liver cancer case-control study. PC-PR2 was used to quantify the variability of metabolomic profiles in terms of study subjects age, sex, body mass index, country of origin, smoking status, diabetes and fasting status, as well as factors related to sample processing. PC-PR2 enables the evaluation of important sources of variations in metabolomic studies within large-scale epidemiological investigations.
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| 33289. |
- Faggiano, Pompilio, et al.
(författare)
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Cardiac calcification as a marker of subclinical atherosclerosis and predictor of cardiovascular events : A review of the evidence
- 2019
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Ingår i: European Journal of Preventive Cardiology. - : Sage Publications. - 2047-4873 .- 2047-4881. ; 26:11, s. 1191-1204
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Forskningsöversikt (refereegranskat)abstract
- Risk prediction of future atherothrombotic cardiovascular events is currently based on conventional risk factor assessment and the use of validated algorithms, such as the Framingham Risk Score, the Pooled Cohort Equations, and the European SCORE Risk Charts. However, the identification of subclinical organ damage has emerged as a potentially more accurate predictor of individual risk. Several imaging modalities have been proposed for identification of preclinical atherosclerosis. Coronary artery calcification scanning performed using cardiac computed tomography and calculation of the Agatston score is the most commonly used technique in clinical practice for detection of subclinical disease, prognostic stratification of asymptomatic individuals and implementation of preventive strategies. Furthermore, conventional echocardiographic examination may offer an assessment of cardiac calcifications at different sites, such as the mitral apparatus (including annulus, leaflets and papillary muscles), aortic valve and ascending aorta, that are associated with the clinical manifestation of atherosclerotic disease and are predictive of future cardiovascular events. The aim of this paper is to summarize available evidence on the clinical use of cardiac calcification, review the pathogenetic mechanisms involved, including similarities with atherosclerosis, and evaluate its potential for risk stratification and prevention of clinical events in the primary prevention setting.
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| 33290. |
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