| 1. |
- Bexell, Göran, et al.
(författare)
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"Ge forskningen mer resurser"
- 2003
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Ingår i: Sydsvenska dagbladet. - 1104-0068.
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 2. |
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| 3. |
- Adler, Jeremy
(författare)
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The unitary scale bar : human and machine readable
- 2008
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 230:1, s. 163-166
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Tidskriftsartikel (refereegranskat)abstract
- A format is described for a scale bar that encodes the length represented within the structure of the bar itself, thereby removing the need for any supporting text. Although the 'unitary' scale bar has a conventional appearance it is also machine readable and therefore retains information about the scale even when the file format is changed. The format is based on the metre and is suitable for all terrestrial applications.
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| 4. |
- Axelsson, Monica, 1950-, et al.
(författare)
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Kunskap och språk - meningsskapande i naturvetenskap
- 2009
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Konferensbidrag (refereegranskat)abstract
- Barns möte med skolan innebär också ett möte mellan det vardagsspråk barnen blivit kompetenta språkbrukare i och skolspråket som de kan vara mer eller mindre främmande inför. Eftersom språket är människans viktigaste redskap för meningsskapande och skolans ämnen konstitueras av språket kommer eleverna under skolåren behöva bli medvetna om att olika sammanhang i skolan kräver olika språkbruk. I detta forskningsprojekt studeras språkets roll för utvecklingen av naturvetenskapligt lärande. Syftet med studien är att på makro- och mikronivå undersöka hur lärare ämnesmässigt och språkligt stöttar yngre (6-10 år) andraspråksutveckling i skolans naturvetenskapliga ämnen och vilken betydelse denna stöttning har för elevernas språk- och kunskapsutveckling i naturvetenskap. Med makronivå avses de stöttande aktiviteter läraren redan från början planerat och integrerat i undervisningen och med mikronivå avses den mer spontana interaktion som uppstår mellan lärare-elev och elev-elev under dessa aktiviteter. Projektet löper under två år där det första året (ht 08-vt09) är ett forskningsår då material samlas in i olika klasser från förskoleklass till årskurs 4. Datainsamlingen består av observationer när barn deltar i naturvetenskapliga aktiviteter i klassrummet, ljud- och videoinspelningar. fotografier, samtal med lärare och elever samt insamling av lärarplaneringar, elevarbeten och läromedelstexter. Under det andra året (ht09-vt10) möts deltagande lärare från insamlingsåret och forskarna i en aktiionsforskningsgrupp. Denna fas innebär att det insamlade materialet presenteras för lärarna och att analysen av stöttningen ur makro- och mikroperspektiv återkopplas och diskuteras. Resultatet av denna analys och diskussion förväntas leda till en uppsättning "mer framgångsrika" sätt att stötta elevers utveckling i de naturvetenskapliga ämnena som lärarna i denna fas prövar i sina respektive elevgrupper. Genom interaktionen i aktionsforskningsgruppen planerar varje lärare nya aktiviteter i sin elevgrupp, observerar och reflekterar över skeendet samt återför sina reflektioner till gruppen. Forskarna medverkar även detta andra år ute i klasserna med ytterligare materialinsamlingar för att dokumentera utvecklingen. I presentationen ges exempel på hur lärare och elever konstruerar mening under lektioner i naturvetenskap. Det insamlade materialet kommer att analyseras med utgångspunkt i Hallidays (1975) registervariabler field, tenor och mode kopplat till praktiska epistemologier (Wickman & Östman, 2002) och lärares epistemologiska drag (moves) (Lidar, Lundqvist & Östman, 2005) samt jämföras med Lemkes tematiska mönster (1990).
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| 5. |
- Balksten, Kristin, 1977-, et al.
(författare)
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A method to recreate historic mortars applied at Norrlanda church on the island of Gotland, Sweden
- 2008
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Konferensbidrag (refereegranskat)abstract
- In this work, scanning electron microscopy analysis of lime slaked in different ways and analysis of thin section limeputty and mortar specimens by light microscopy was combined with practical tests and field studies in order to evaluatethe impact of the slaking technique on the properties of the lime putty, and also the structure of the fresh and carbonatedmortar. The lime slaking methods studied were wet slaking and earth slaking. These techniques give lime putties withvery different consistency and workability. The aim of this work was to use microscopy techniques to explain thesedifferences in properties and to investigate if it is possible to use these analytical methods to recognize the lime slakingtechnique used in a historical lime mortar.The results obtained by electron microscopy show significant differences in structure between the lime puttiesstudied. The earth slaked lime consists of relatively large particles that are packed in a porous system as compared to thewet slaked lime with very small particles closely packed in a dense structure. After storing, the wet slaked lime gives aputty, that has a dense and clearly defined stratified structure, whereas the earth slaked lime is porous and has nostratification. The earth slaked lime is tixotropic and has a light, smooth consistency reminding of well whipped creamcompared to the wet slaked lime that has a strong orientation and a rather stiff consistency reminding more of pudding.Microscopy investigations of thin section mortar specimens showed how the lime affects the mortar concerninghomogeneity, density, pore structure and crack patterns.
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| 6. |
- Balksten, Kristin, 1977-
(författare)
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Kalkputs : porstrukturens betydelse för beständighet
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When restoring historic lime plaster it can be difficult to reach the required durability. Today newly made lime plaster can fall off due to frost damages after only a couple of winters. To understand and solve these problems, the subject has been studied from different perspectives. Several factors in the production step are making an influence on the durability of lime plaster: 1. A binder, suitable for the building, must be chosen along with sandthat gives good material properties in both fresh mortar and in plasters. 2. The lime/sand ratio and the mixing technique should be chosen from the properties in the lime and the sand, in order to get a mortar with good workability. 3. The craftsmanship should be adjusted to the mortar, the weather and the underlying materials. A plaster with good frost resistance has a certain pore structure. The plaster should have some round air pores that contain air even when the material is filled capillary with water. Such air pores give the water a free space to expand when it is freezing. If the air pores are missing, the ice crystals may damage the plaster when expanding. To increase the chance of making a frost resistant lime plaster, the lime/sand ration must be adjusted so the lime can fill up well in the sand. Otherwise a collapsed pore system can easily occur, which means an open pore system without distinct air pores. A collapsed pore system contains many pores well connected with each other. Such a system is easily damaged by frost. To increase the chance of success, it is of great importance to work the surface of the lime plaster at the right time and in the correct way. Before working on a surface the mortar must be aloud to stiffen. Only then a homogeneous material can be created; cracks due to shrinkage can be pressed together and the result is a more compact material with an open surface. The time necessary for mortars to stiffen is related to the water content of the mortar, the suction of the underlying surface and the weather conditions. If the surface is worked on while the mortar is still fresh, the binder can form a hard lime shell on the surface. Inside thematerial a lack of binder can appear. Such plasters have a very low frost resistance. Other durability problems related to plaster are damages in the underlying materials, i.e. rotten wood in covered constructions or leached lime in old joints. Such damages can occur if the covering mortar is made of strong hydraulic lime or cement, since they form plasters with a low permeability in comparison to lime. Due to mentioned findings, it is important to study how a pore structureis influenced by materials, mixture and craftsmanship. Only then it is possible to understand how damages can be decreased.
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| 7. |
- Balksten, Kristin, 1977-, et al.
(författare)
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Lime-based Repair Mortars : Influence by Surface Working Methods onBehaviour and Durability of Mortar
- 2006
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Konferensbidrag (refereegranskat)abstract
- The main purpose of this study was to observe the influence by different surface working methodson behaviour, durability and appearance of lime-based stone-repair mortars.The findings are based on:- Observations made during restoration work- Observations from field stations- Microscopic analysis of thin sections of mortar- Parallel studies on lime plasterThe results show clear differences in durability, appearance and behaviour of lime-based mortar dependingon at which stage of the drying process the mortar is worked on. For achieving durable mortar it is importantto avoid the development of a surface lime-film. The study implies that the mortar, only when worked on at aspecific stage of drying, will be durable and have a structure, texture and porosity compatible with the surroundingstone material.
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| 8. |
- Balksten, Kristin, 1977-, et al.
(författare)
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Permeability in lime plaster in relation to durability of covered materials
- 2004
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Ingår i: Proceedings of the 32nd IAHS World Congress on Housing – Sustainability of the Housing Projects. Trento, Italy 2004.. ; 1
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Konferensbidrag (refereegranskat)abstract
- In restoration of old buildings, lime plasters are used for reasons of authenticity and for technicalreasons as well. In many traditional constructions, there is wood behind the plasters or there is old limemortar in the masonry. For the durability of both these underlying materials, it is important that therelative humidity, RH is not too high under a long time of exposure. This can lead to an accelerateddegradation process of wood and leaching of lime in mortars. To prevent this, the plaster must have aproper permeability.The permeability of a material determines its ability to transport gas and moisture. In lime plasters,permeability affects hardening, carbonation as well as durability of the underlying materials. In thepresent paper, eleven mixtures of lime mortar were studied. The binders used were lime slaked in fourdifferent ways, hydraulic lime and cement.The following measurements were made to analyse the permeability and the pore structure of thesamples. Gas permeability and draining curves give an indication of rate of carbonation. Vapourpermeability shows the ability of plaster to transmit moisture at different RH. Thin sections were madefor microscopically investigations of the samples.The investigations show that both the vapour permeability and gas permeability decreases with anincreased amount of hydraulic binder in the lime plasters. Even small amounts of hydraulic binderhave a significant effect.By connecting these results with examples from reality, the picture becomes clearer. In the medievaltown Visby in Sweden, there are several examples of both rotten wood and disintegrated lime mortars.It is constructions from 13th to 19th centuries and low permeable cementitious plasters have coveredthem all, during the middle of the 20th century.
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| 9. |
- Balksten, Kristin, 1977-, et al.
(författare)
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The influence of craftsmanship on the inner structures of lime plasters
- 2005
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Ingår i: Proceedings of the International RILEM Workshop Repair Mortars for Historic Masonry. Delft, Holland 2005.. - : Rilem publications. ; 1, s. 11-20
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Konferensbidrag (refereegranskat)abstract
- The use of traditional lime plaster in restoration of old buildings is motivated by bothtechnical and historic reasons. The plasterer deals daily with a multivariable problem wherethe variables are related in such a complex way that we are not even close to findingconverging solutions by traditional scientific methods. The decisions and actions of thecraftsman will have an influence on both the surface structure and the inner structure of thelime plaster. The present paper will focus on the time between application of mortar andworking on the surface to make a floated finish. In total, 32 lime plaster surfaces have beenanalysed. Half of them have been worked on after they have stiffened up and half of themhave been worked on while they are still fresh. The results clearly show that the time betweenapplication of mortar and working the surface is a critical parameter. If you wait until theright time, you receive a more homogeneous and compact material with an open surface anda higher frost resistance.
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| 10. |
- Balksten, Kristin, 1977-, et al.
(författare)
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The pore structure in lime plaster as a key to understanding moisture transportation properties and frost damages
- 2004
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Ingår i: 10th International Congress on the Deterioration and Conservation of Stone. ; 2, s. 1033-1040
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Konferensbidrag (refereegranskat)abstract
- The pore structure is of great importance for a materials ability to hold and transport gasand moisture. In lime plaster, it affects hardening, carbonation as well as durability againstfrost damage. In the present paper, eleven mixtures of lime mortar were studied withrespect to frost damages. The binders used were lime slaked in four different ways,hydraulic lime and cement.Several analyses were made to characterize the transport properties and the porestructure of the materials; density, porosity, sorption curves, capillary water suction andthin sections. This study shows that there is a correlation between pore structure andimportant material properties. By studying these parameters, it is possible to get a goodpicture of the materials ability to resist frost damages. The study also gives an indication ofwhat materials in the mortar such as binders, aggregates and water, give a good porestructure.
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