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| 3. |
- Engberg, Elisabeth, 1961-
(författare)
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I fattiga omständigheter : Fattigvårdens former och understödstagare i Skellefteå socken under 1800-talet
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to shed light upon the Swedish nineteenth century poor relief system, how it operated in a local rural context, how it changed over time, and not least, who was supported and why. It raises questions about how the poor laws were interpreted on the parish level, how the welfare systems interacted with local society and about who was considered to be poor and entitled to support. The geographical setting of the thesis is Skellefteå, a rural parish in northern Sweden, and it concentrates upon the period 1830–1875.Swedish poor relief was governed by the fundamental principle that each parish had a duty to support their own poor and each parish was allowed a large amount of freedom to adjust their welfare arrangements according to local conditions. In Skellefteå, the main incentive for modification of the poor relief system was not new regulations from the national level, but social and economic transformations on the local level. This implies that local requirements were put before national legislation and suggests the existence of several regional, and perhaps also local, poor relief systems in nineteenth-century Sweden.On the local level, the results indicate the existence of a parochial social citizenship based upon a common understanding of social rights and duties in the community, and grounded in a strong sense of affiliation with the local society. Generally there was a larger distance between the poor and their providers in the wealthier and more socially stratified villages, hence a more egalitarian context seem to have facilitated identification and empathy with the poor. The local provision for the poor created and maintained bonds within a community, as well as it helped to build and reinforce boundaries towards those who did not belong. A sometimes suspicious and negative attitude towards outsiders was to some extent caused by a fear of increased poor relief expenses, but it also bears witness to a rural culture with a strong sense of belonging to one’s own village or hamlet.The majority of men and women supported by poor relief in Skellefteå belonged to the lower strata of society long before they became welfare recipients. They were landless rural people with weak kinship networks, that in most cases were unable to mobilize any significant support in times of need. Childhood, early middle age, and old age were identified as phases in the life cycle that seem to have entailed an increased risk of poverty and dependence. A substantial proportion of the poor were breadwinners, middle aged men with large households to support, while the widowed and unmarried paupers usually were women. For many of these households the life cycles’ vulnerable periods were further reinforced by other factors: a breadwinner’s illness or disability, the death of a spouse, a major subsistence crisis, or a larger marginalization caused by a deviation from society’s moral standards. In most cases there seems to have been a delicate interplay between several social risks that determined if and when a person or a household was to end up being supported by poor relief.
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| 4. |
- Engberg, Göran, et al.
(författare)
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A Physically based Microstructure Model for Predicting the Microstructure Evolution of a C-Mn Steel during and after Deformation
- 2008
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Ingår i: Steel Research International. - Düsseldorf : Verlag Stahleisen GMBH. - 1611-3683 .- 1869-344X. ; 79:1, s. 47-58
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Tidskriftsartikel (refereegranskat)abstract
- A physically based model for predicting microstructural evolution has been developed. The model is based on a physical description of dislocation density evolution, where the generation and recovery of dislocations determine the flow stress and also the driving force for recrystallization. In the model, abnormally growing subgrains are assumed to be the nuclei of recrystallized grains and recrystallization starts when the subgrains reach a critical size and configuration. To verify that the model is able to describe dynamic, static and metadynamic recrystallization of C-Mn steels, hot compression tests combined with relaxation were performed at various temperatures, strains and strain rates. The model showed reasonable agreement with the experimental data for the compression tests performed at temperatures ranging from 850?C to 1200?C and strain rates ranging from 0.1 to 10 s-1. Also, the calculations of the stress relaxation tests show good agreement with experimental data. A validation of the model was done by calculating a multi-step test where good agreement with both flow-stress values and grain sizes was obtained. The main purpose of the model is to be able to predict the microstructural evolution during hot rolling and this investigation presents very promising results.
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| 5. |
- Engberg, Göran, et al.
(författare)
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Analysing metal working processes
- 2005
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Ingår i: Fundamentals of metallurgy. - Cambridge : Woodhead Publishing ltd. - 9781855739277 ; , s. 453-470
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Metal working processes encompass a wide range of strain, strain rates and temperatures. Strains range from less than 0.01 (for example in skin-pass rolling of interstitial free steel) up to around 1 (cold rolling of strip, extrusion, etc.). Typical strain rates and temperatures are given in Table 11.1 (which is partly an extract from Frost and Ashby (1982). For plastic forming processes the most important characteristics of the material are: the ability to distribute strains; the deformation resistance; and the resulting properties of the formed part. The ability to distribute strains is mainly governed by the work hardening and strain-rate sensitivity. It is also affected by the strain path. The purpose of this paper is to outline the, in our view, most essential material properties for metal working processes and the microstructural reasons for them. We recognise that the presence and development of crystallographic texture is quite an important part but our purpose is not to give an extensive description of this, only to point out some consequences. For further reading we recommend a book by Kocks, Tomé and Wenk (1998). Another aspect that is only briefly covered is the influence of stress states and changes in strain paths during processing or between consecutive process steps.
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| 6. |
- Hashimoto, Kenji, et al.
(författare)
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Elevated glutamine/glutamate ratio in cerebrospinal fluid of first episode and drug naive schizophrenic patients
- 2005
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Ingår i: BMC Psychiatry. - 1471-244X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recent magnetic resonance spectroscopy (MRS) studies report that glutamine is altered in the brains of schizophrenic patients. There were also conflicting findings on glutamate in cerebrospinal fluid (CSF) of schizophrenic patients, and absent for glutamine. This study aims to clarify the question of glutamine and glutamate in CSF of first episode and drug naive schizophrenic patients. Method: Levels of glutamine and glutamate in CSF of 25 first episode and drug-naive male schizophrenic patients and 17 age-matched male healthy controls were measured by a high performance liquid chromatography. Results: The ratio (126.1 (median), 117.7 ± 27.4 (mean ± S.D.)) of glutamine to glutamate in the CSF of patients was significantly (z = -3.29, p = 0.001) higher than that (81.01 (median), 89.1 ± 22.5 (mean ± S.D.)) of normal controls although each level of glutamine and glutamate in patients was not different from that of normal controls. Conclusion: Our data suggests that a disfunction in glutamate-glutamine cycle in the brain may play a role in the pathophysiology of schizophrenia. © 2005 Hashimoto et al, licensee BioMed Central Ltd.
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| 8. |
- Karlsson, Maths, 1978, et al.
(författare)
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Quasielastic neutron scattering of hydrated BaZr0.90A0.10O2.95 (A = Y and Sc)
- 2009
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 180:1, s. 22-28
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Tidskriftsartikel (refereegranskat)abstract
- Proton motions in hydrated proton conducting perovskites BaZr 0.90 A 0.10 O 2.95 (A = Y and Sc) have been investigated using quasielastic neutron scattering. The results reveal a localized motion on the ps time scale and with an activation energy of ~ 10-30 meV, in both materials. The temperature dependence of the total mean square displacement of the protons shows an onset of this motion at a temperature of about 300 K. The low activation energy, much lower than the activation energy for the macroscopic proton conductivity, suggests that this motion is not the rate-limiting process for the long-range proton diffusion, i.e. it is not linked to the two materials significantly different proton conductivities. In fact, a comparison of the QENS results with density functional theory calculations indicates that for both materials the observed motion may be ascribed to intra-octahedral proton transfers occurring close to a dopant atom. © 2008 Elsevier B.V. All rights reserved.
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| 9. |
- Karlsson, Maths, 1978, et al.
(författare)
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Vibrational Properties of Protons in Hydrated BaInxZr1-xO3-x/2
- 2005
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 72, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the local proton dynamics in the proton conducting hydrated perovskite system BaInxZr1-xO3-x/2 (x=0.25-0.75) using infrared spectroscopy and first-principles calculations. We show that oxygen vacancies and dopant atoms in the vicinity of the proton tilt the proton toward a neighboring oxygen creating strongly hydrogen-bonded configurations. This is manifested as a strong redshift of the O-H stretch band in the infrared absorption spectrum. We also find considerable fluctuations of the nearest and next-nearest oxygen-proton distances with time, resulting in additional spectral broadening. By comparing the frequencies of computed O-H stretch modes we can relate specific local configurations to different parts of the broad O-H stretch band. Even though hydrogen-bonded configurations favor proton transfer they hinder the long-range migration by decreasing the reorientational rate. Thus, in order to optimize the proton mobility it is important to avoid extreme configurations caused by either oxygen vacancies or dopant atoms in the perovskite structure.
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| 10. |
- Lissel, Linda, et al.
(författare)
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Modeling precipitation and its effect on recrystallization during hot strip rolling of niobium steels
- 2008
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Ingår i: 3rd Int. Conf. on Thermomechanical Processing of Steels. - Padua, Italy.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Using a physically based model, the microstructural evolution of Nb microalloyed steels during rolling in SSAB Tunnplåt’s hot strip mill was modeled. The model describes the evolution of dislocation density, the creation and diffusion of vacancies, dynamic and static recovery through climb and glide, subgrain formation and growth, dynamic and static recrystallization and grain growth. Also, the model describes the dissolution and precipitation of particles. The impeding effect on grain growth and recrystallization due to solute drag and particles is accounted for. During hot strip rolling of Nb steels, Nb in solid solution retards recrystallization due to solute drag and at lower temperatures strain-induced precipitation of Nb(C,N) may occur which effectively retard recrystallization. The flow stress behavior during hot rolling was calculated where the mean flow stress values were calculated using both the model and measured mill data. The model showed that solute drag has an essential effect on recrystallization during hot rolling of Nb steels.
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| 11. |
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| 12. |
- Lissel, Linda, et al.
(författare)
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Prediction of the microstructural evolution during hot strip rolling of Nb microalloyed steels
- 2007
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Ingår i: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 558-559:2, s. 1127-1132
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A physically based model is used to describe the microstructural evolution of Nb microalloyed steels during hot rolling. The model is based on a physical description of dislocation density evolution, where the generation and recovery of dislocations determines the flow stress and also the driving force for recrystallization. In the model, abnormally growing subgrains are assumed to be the nuclei of recrystallized grains and recrystallization starts when the subgrains reach a critical size and configuration. The model is used to predict the flow stress during rolling in SSAB Tunnplat's hot strip mill. The predicted flow stress in each stand was compared to the stresses calculated by a friction-hill roll-force model. Good fit is obtained between the predicted values by the microstructure model and the measured mill data, with an agreement generally within the interval +/-15%.
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| 13. |
- Magnusson, Hans, 1979-
(författare)
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Creep modelling of particle strengthened steels
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Materials to be used in thermal power plants have to resist creep deformation for time periods up to 30 years. The role of alloying elements for creep strength of 9-12% Cr steels is analysed. The creep strength in these steels relies on minor additions of alloying elements. Precipitates give rise to the main strengthening and remaining elements produce solid solution hardening. Nucleation, growth and coarsening of particles are predicted by thermodynamic modelling. Phase fractions and size distributions of M23C6 carbides, MX carbonitrides and Laves phase are presented. The size distributions are needed in order to determine the particle hardening during creep. At elevated temperatures the climb mobility is so high that the dislocations can climb across particles instead of passing by making Orowan loops. By solving Fick's second law the concentration profile around a moving dislocation can be determined. The results show an accumulation of solutes around the dislocation that slows down dislocation movement. When Laves phase grows a decrease in creep strength is observed due to a larger loss in solid solution hardening than strength increase by particle hardening. Solid solution hardening also gives an explanation of the low dislocation climb mobility in 9-12% Cr steels. Three different dislocation types are distinguished, free dislocations, immobile dislocation and immobile boundary dislocations. This distinction between types of dislocations is essential in understanding the decreasing creep with strain during primary creep. The empirical relation with subgrain size inversely proportional to stress has been possible to predict. The total creep strength can be predicted by adding the contribution from individual mechanisms.
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| 14. |
- Nilsson, Linda K, et al.
(författare)
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Cerebrospinal fluid kynurenic acid in male and female controls - Correlation with monoamine metabolites and influences of confounding factors
- 2007
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Ingår i: Journal of Psychiatric Research. - : Elsevier BV. - 0022-3956 .- 1879-1379. ; 41:1-2, s. 144-151
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations of the tryptophan metabolite kynurenic acid (KYNA) and the monoamine metabolites homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA) and 4-hydroxy-3-methoxyphenylglycol (HMPG) were determined in the cerebrospinal fluid (CSF) from 43 healthy volunteers (30 males and 13 females). Healthy female controls displayed higher CSF concentration of KYNA (1.91 nM ± 0.20) compared to healthy male controls (1.06 nM ± 0.07) and lower CSF levels of HMPG (39.2 nM ± 2.0 and 43.4 ± 1.2, respectively). CSF levels of HVA and 5-HIAA did not differ between females (181.3 nM ± 21.9 and 93.7 nM ± 11.4, respectively) and males (138.9 nM ± 12.6 and 74.8 nM ± 5.9, respectively). Positive intercorrelations were found between CSF KYNA, HVA and 5-HIAA while CSF content of HMPG did not correlate with KYNA or the other monoamine metabolites in CSF. A negative correlation was found between back length and CSF concentrations of KYNA, HVA and 5-HIAA and also between CSF KYNA levels and body height. The results of the present study suggest that concentrations of KYNA and the monoamine metabolites in CSF from healthy controls are dependent on gender and back length, which must be taken in consideration when analysing mixed groups of men and women. The higher KYNA concentration found in female controls compared to male might be attributed to a shorter back in women compared to men. Furthermore, these findings suggest that increased KYNA formation is associated with an increased dopamine and serotonin turnover. © 2005 Elsevier Ltd. All rights reserved.
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| 16. |
- Wang, X.T., et al.
(författare)
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Physical Modeling on Recrystallization of Austenite in Steels in Thermo-mechanical Processing
- 2007
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Ingår i: Materials Science Forum. - Switzerland : Trans Tech Publications. - 1662-9752. ; 561-565, s. 1953-1956
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A physical model for austenite recrystallization of steel concerning TMCP is developed. Dislocation density plays a key role as recrystallization driving force. The dislocation density change is a result of competition between dislocation generation and dynamic recovery. Recrystallization is described as a nucleation-growth process. An abnormal subgrain growth mechanism is introduced for nucleation. A few subgrains fulfilling abnormal growth conditions will stand out and become nuclei of recrystallization. The recrystallized grain grows to the deformed materials driven by the stored energy. Oswald ripening occurs for grains surrounded by recrystallized grains. The models were verified by laboratory simulation results for selected austenite stainless steels. It showed good agreement between predicted and experimental results.
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