| 1. |
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| 2. |
- Babic, N.C., et al.
(författare)
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InPro training environment and model based working in construction
- 2009
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Ingår i: Improving Construction and Use through Integrated Design Solutions. - Espoo : Valtion teknillinen tutkimuskeskus. Tie- ja liikennelaboratorio. - 9789513863418 ; , s. 72-86
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Konferensbidrag (refereegranskat)abstract
- InPro project is European initiative which is developing a model based and collaborative way of working in early design phase in construction. To support project goals and facilitate the industrial transformation and industrial technology take-up, the project implemented tools and developed curricula and materials for training and education of management, architects, engineers, and construction workers, as well as university students. The paper presents training environment architecture with BIM laboratory that was developed to support training on model based work practices and enhancement of hands-on skills. Development process, technical solutions and experiences are described. Content of training courses and curricula is based on experiences from live project demonstrations and use cases. The paper presents one of the answers that address the problem of insufficient skills in construction industry that prevent adoption of novel methods of working and technology.
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| 3. |
- Bennitz, Anders, et al.
(författare)
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Dynamic behaviour of the Vindel River railway bridge
- 2006
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Ingår i: Condition Monitoring and Diagnostic Engineering Management. - Luleå : Luleå tekniska universitet. - 9789163188060 ; , s. 721-729
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Konferensbidrag (refereegranskat)abstract
- The Swedish Railway administration has launched several projects aimed at increasing the accessibility of the railway lines in northern Sweden to meet future demands. One of these lines connects the southern and northern parts of Sweden and constitutes one of the major arteries for the transportation of heavy goods. Major investment are planned to upgrade the load bearing capacity of this railway line. The work is mainly focused on the larger structures and their dynamical properties. These properties can be used to assess existing infrastructure and to evaluate the performance. Advantages are obvious since the existing structural integrity form the base for investments in structural repair and upgrade of bridges. The Vindel River Railway Bridge situated 55 kilometers northwest of Umeå came into focus when large motion was discovered during train passages. The behaviour of the bridge crossing the river of Vindeln has been measured two times. Measurements of displacements and acceleration of the bridge during train passages has been conducted, the first measurements was done to give more experience on the motion of the bridge and to try out new sensors. The second measurement gave more information about the bridge's motion, results that could be used to calibrate a 3D FE-Model of the bridge used in the study. Based on the measurements, eigenfrequencies in the range of 0 to 8 Hz could be detected, modal shapes up to the ninth order could be extracted, deflections and transverse displacements for different sets of train and different train speeds were also found. However, new measurements are planned for this summer and will hopefully reinforce the already attained result and give answers to some of the unresolved questions.
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| 4. |
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| 5. |
- Chioza, Barry A., et al.
(författare)
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Genome wide high density SNP-based linkage analysis of childhood absence epilepsy identifies a susceptibility locus on chromosome 3p23-p14
- 2009
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Ingår i: Epilepsy Research. - : Elsevier BV. - 0920-1211 .- 1872-6844. ; 87:2-3, s. 247-255
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Tidskriftsartikel (refereegranskat)abstract
- Childhood absence epilepsy (CAE) is an idiopathic generalised epilepsy (IGE) characterised by typical absence seizures manifested by transitory loss of awareness with 2.5-4 Hz spike-wave complexes on ictal EEG. A genetic component to the aetiology is well recognised but the mechanism of inheritance and the genes involved are yet to be fully established. A genome wide single nucleotide polymorphism (SNP)-based high density linkage scan was carried out using 41 nuclear pedigrees with at least two affected members. Multipoint parametric and non-parametric linkage analyses were performed using MERLIN 1.1.1 and a susceptibility locus was identified on chromosome 3p23-p14 (Z(mean)=3.9, p<0.0001; HLOD=3.3, alpha=0.7). The linked region harbours the functional candidate genes TRAK1 and CACNA2D2. Fine-mapping using a tagSNP approach demonstrated disease association with variants in TRAK1.
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| 6. |
- Dannefjord, Per, 1964-
(författare)
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Organisationspraktiker och målförändring : Exemplet svensk socialdemokrati
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis emanates from a comparison between three points of time in the history of the Swedish social democratic party (SAP); 1889, 1905 and 1933. The comparison is partly about the political and organizational situation of the party, and partly about the goals the party expressed. The problem that I study, based on this comparison, is the identified changes of the party’s hierarchy of goals.I argue that goal change should be viewed as a process, not as a decision. There is no simple rationality in goal formulations or in the relation between goals and practices where the practices are shaped by the goals.My case shows the importance of the opposite causal direction where the practices reshape the goals. The organization formulates goals and intermediate goals. These are connected to practices directed towards the intermediate goals. The more resources the organization attach to these practices, the more difficult it is to change them and the higher status in the organizational activity they will get. The primary goals can still be important as justification, but their role will be reduced to a ritual rhetoric without practical significance. They will have to be reinterpreted and reformulated in correspondence to the practices in order to regain a practical significance in the activity of the organization. Thereby we have a practical goal change, which shouldn’t be confused with at rhetoric goal change. The rhetoric of the organization can remain unchanged even though no practices are directed towards the rhetorically important goals.One implication of this is that goals cannot be understood by their formulations only. The importance and meaning of the formulations will change over time and should therefore be related to the context and the organization’s position in the organizational field. When we study an organization over time it will be hard to understand it adequately if we don’t relate the organizational changes to the context.
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| 7. |
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| 8. |
- Dehlin, Stefan, et al.
(författare)
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An evaluation model for ICT investments in construction projects
- 2008
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Ingår i: Electronic journal of information technology in construction. - 1403-6835 .- 1400-6529. ; 13, s. 343-361
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Tidskriftsartikel (refereegranskat)abstract
- Even though Information and Communication Technology (ICT) investments in construction projects generally represent minor commitments of project resources by comparison to the full project cost, the value or impact on the profitability of the project are generally not considered. Also, many of the investment decisions are poorly thought through or examined. Investments decision taken during the procurement phase often merely based on intuition and rough estimations of the future costs and risks. Also, many of the traditionally used appraisal approaches have been shown inadequate in anticipating the consequences of such an investment. As a result, the investment is too often assumed to be negative since the benefits are not proper evaluated, included and weighted against the costs and risks the investment is expected to generate. Poor decision-basis does not only affect the actual decision-making in a particular project but also, in the long run, the motivation to innovate and to introduce new ICT tools and working methods into the construction industry. In view of this, a new project-oriented evaluation model is developed for the purpose to provide for a structure and a work routine to be used by a multidisciplinary project team to evaluate the implications of realizing ICT investments in construction projects. Although primarily aimed at establishing future benefits and costs the model may very well be used for follow-ups. The models' application is illustrated using a case study of a construction project using 3D and VR for coordination and evaluation. The results based on interviews and rough estimates on the "safe side" show that benefit of the ICT investment for the case study project was much higher compared with the cost for the project. The shift in focus from costs/benefits for the individual stakeholders to costs/benefits for the project gives a momentum to optimize the use of a new ICT tools in construction. This will surely affect the processes and the contractual environment in the project, since it has to support sharing of information and achieved benefits and the costs of the investment in the project.
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| 9. |
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| 10. |
- Enochsson, Ola, et al.
(författare)
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Assessment and condition monitoring of a concrete railway bridge in Kiruna, Sweden
- 2006
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Ingår i: Bridge maintenance, safety, management, life-cycle performance and cost. - London : Taylor and Francis Group. - 0415403154
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Konferensbidrag (refereegranskat)abstract
- A two-span railway concrete trough bridge over Luossajokk in Kiruna in northern Sweden has been studied. The owner wanted to increase the axle loads from 250 to 300 kN in order to reduce freight costs for iron ore. Examples are given of methods used and results obtained from the assessment where bending, shear and fatigue were studied. Material properties, loads and load carrying capacity were evaluated using deterministic and probabilistic methods. It was shown that the bridge could carry the higher loads with a safety index β > 4.7 for reasonable assumptions of the load distributions. A measurement system was installed to check the actual level of critical strains and the worst positions of the train. Results are also given from a condition monitoring program 2001-2006, launched to periodically check the development of strains with time.
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| 11. |
- Enochsson, Ola, et al.
(författare)
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Bro över Luossajokk : övervakning för trafikering med 30 tons axellast
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I samband med projektet "30 ton på Malmbanan", Paulson-Töyrä (1996), konstaterades att bron över Luossajokk i Kiruna inte klarade de nya förhöjda lasterna. Bron har två spann och en utkragande konsol 10,25 + 6,3 + 3,4 m. Överbyggnaden utgörs av ett slak-armerat betongtråg med ett nytt mellanstöd som uppfördes 1965 då en äldre överbyggnad byttes ut. En klassningsberäkning och en utredning av förstärkningsbehov utfördes. Efter en förnyad översyn av brons bärförmåga utfördes töjningsmätningar vintern och sommaren 2001. Töjningsmätningarna indikerade förvånansvärt små påkänningar i bron. En närmare utredning av brons säkerhet att bära uppträdande laster utfördes 2002 genom en nyanserad säkerhetsberäkning med säkerhetsindexmetod. Bron bedömdes utifrån utredningen och mätresultat ha erforderlig bärförmåga om hastigheten begränsades så att eventuella dynamiska tillskott blir låga och/eller inverkan av ojämn temperatur försummas. Ett program med mätningar varje halvår igångsattes för att kontrollera brons fortsatta uppförande. Kontrollen bestod i en övervakning av aktuella töjningsnivåer i armeringen.I denna rapport redovisas resultat från mätningar mellan år 2001-2006. Resultaten visar ingen ökning av töjningsnivåerna fram till brons avlägsnande hösten 2006.
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| 12. |
- Enochsson, Ola, et al.
(författare)
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CFRP Strengthened openings in two-way concrete slabs
- 2005
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Ingår i: FRP composites in civil engineering - CICE 2004. - Leiden : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 9058096386
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Konferensbidrag (refereegranskat)
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| 13. |
- Enochsson, Ola, et al.
(författare)
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CFRP strengthened openings in two-way concrete slabs : an experimental and numerical study
- 2007
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 21:4, s. 810-826
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Tidskriftsartikel (refereegranskat)abstract
- Rehabilitation and strengthening of concrete structures with externally bonded fibre reinforced polymers (FRPs) has been a viable technique for at least a decade. An interesting and useful application is strengthening of slabs or walls where openings are introduced. In these situations, FRP sheets are very suitable; not only because of their strength, but also due to that they are easy to apply in comparison to traditional steel girders or other lintel systems. Even though many benefits have been shown by strengthening openings with FRPs not much research have been presented in the literature. In this paper, laboratory tests on 11 slabs with openings, loaded with a distributed load are presented together with analytical and numerical evaluations. Six slabs with openings have been strengthened with carbon fibre reinforced polymers (CFRPs) sheets. These slabs are compared with traditionally steel reinforced slabs, both with (four slabs) and without openings (one slab). The slabs are quadratic with a side length of 2.6 m and a thickness of 100 mm. Two different sizes of openings are used, 0.85 × 0.85 m and 1.2 × 1.2 m. The results from the tests show that slabs with openings can be strengthened with externally bonded CFRP sheets. The performance is even better than for traditionally steel reinforced slabs. The numerical and analytical evaluations show good agreement with the experimental results.
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| 14. |
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| 15. |
- Enochsson, Ola, et al.
(författare)
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Condition assessment of concrete bridges in Sweden
- 2005
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Ingår i: Concrete repair, rehabilitation and retrofitting. - London : Taylor and Francis Group. - 0415396565 ; , s. 257-259
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Konferensbidrag (refereegranskat)abstract
- Examples are given of methods used and results obtained from two bridges assessed in Sweden. The following sectional forces were critical: (a) Bending, shear and fatigue in a two-span railway trough bridge and (b) Shear and torsion in a three-span prestressed cantilever box girder road bridge. In the assessments we evaluated material properties, loads and load carrying capacity using deterministic and probabilistic methods
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| 16. |
- Enochsson, Ola, et al.
(författare)
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Structural health monitoring of a concrete bridge in Sweden
- 2006
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Ingår i: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 6176:18
-
Tidskriftsartikel (refereegranskat)abstract
- Over the past decade the interests in upgrading, assessment and maintenance of our ageing infrastructure has grown avalanche-like. The main reason is economical aspects but also reasons due to accessibility environmental consideration play a vital role. Recently the Swedish and Norwegian Railway Association decided to upgrade the Iron Ore Line "Malmbanan", a railway line for transportation of iron from northern Sweden to the coasts of Norway and Sweden. Here the owner wanted to increase the axle loads from 25 to 30 tons to reduce the transportation costs. In one of the cases, the Luossajokk Bridge, a recalculation according to design codes showed that the increased axle loads would exceed the yield limit in the reinforcement. Before any decision was taken regarding strengthening or replacing the bridge an assessment with probabilistic methods was used. It appeared that the bridge could carry the higher load with a safety index β ≥ 4.7 for reasonable assumptions of the load distributions. A measurement system was installed to check the real worst placement of the new iron ore locomotive (IORE), and the actually level of strains in the reinforcement for the worst load case1. It was shown that the strain level was far from critical and that the evaluated worst placement of the locomotive was almost correct2. To assure a reliable transportation a long term monitoring program was arranged to check the development of strains with time. Examples from the probabilistic evaluation and the monitoring of the bridge are given and discussed.
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| 17. |
- Ericsson, Eva, et al.
(författare)
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Is the P600/affected by the richness of semantic content? : a linguistic ERP study in Swedish
- 2008
-
Ingår i: Scandinavian Journal of Psychology. - : Wiley. - 0036-5564. ; 49, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The study investigated whether the P600/SPS component is sensitive to the richness of semantic content in sentences. ERPs were recorded while 30 native Swedish speakers read sentences, of which half were syntactically correct and half contained a syntactic violation. Both kinds of sentences came in one of three types of descending semantic completeness: semantically coherent sentences, sentences which were incoherent due to violations of selectional restrictions, or sentences of pseudo words, hence void of lexical content. In the semantically coherent sentences a P600/SPS was found for the syntactic violation. A less salient positivity was found for the violation in the semantically incoherent sentences. No P600/SPS was found for the syntactic violation in the pseudo word sentences and no LAN component in any sentence type. The results are interpreted as supporting the hypothesis that the P600/SPS component reflects a semantically based reanalysis process.
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| 18. |
- Everett, Kate, et al.
(författare)
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Linkage and mutational analysis of CLCN2 in childhood absence epilepsy
- 2007
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Ingår i: Epilepsy Research. - : Elsevier BV. - 0920-1211 .- 1872-6844. ; 75:2-3, s. 145-153
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Tidskriftsartikel (refereegranskat)abstract
- In order to assess the chloride channel gene CLCN2 as a candidate susceptibility gene for childhood absence epilepsy, parametric and non-parametric linkage analysis was performed in 65 nuclear pedigrees. This provided suggestive evidence for linkage with heterogeneity: NPL score=2.3, p<0.009; HLOD=1.5, α=0.44. Mutational analysis of the entire genomic sequence of CLCN2 was performed in 24 unrelated patients from pedigrees consistent with linkage, identifying 45 sequence variants including the known non-synonymous polymorphism rs2228292 (G2154C, Glu718Asp) and a novel variant IVS4+12G>A. Intra-familial association analysis using the pedigrees and a further 308 parent–child trios showed suggestive evidence for transmission disequilibrium of the G2154C minor allele: AVE-PDT , p<0.03. Case–control analysis provided evidence for a protective effect of the IVS4+12G>A minor allele: , p<0.008. The 65 nuclear pedigrees were screened for three previously identified mutations shown to segregate with a variety of idiopathic generalised epilepsy phenotypes (597insG, IVS2-14del11 and G2144A) but none were found. We conclude that CLCN2 may be a susceptibility locus in a subset of cases of childhood absence epilepsy.
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| 19. |
- Fransson, Lennart, et al.
(författare)
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On scaling of the maximum ice pressure on a vertical foundation
- 2005
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Ingår i: Proceedings of the 18th International Conference on Port and Ocean Engineering under Arctic Conditions. ; , s. 341-351
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Konferensbidrag (refereegranskat)abstract
- The nature of ice loads on vertical foundations is discussed based on statistical analysis of field data. Measured loads on segments of the total pressure area were typically Weibull distributed with a maximum of about 4 times the mean values. Scale effect on the maximum effective pressure was evident for uniform level ice when calculated for different contact widths. Maximum pressure on a larger contact width decreased but the mean pressure level remained constant. This confirmed the assumption that some but not all of the governing crushing phenomena were statistically independent. Elasticity of the structure or the ice sheet was assumed to increase the length of the independent crushing zones.
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| 20. |
- Hildingsson, Ingegerd, et al.
(författare)
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Still behind the glass wall? Swedish fathers’ experiences with postnatal care
- 2009
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Ingår i: Journal of Obstetric, Gynecologic and Neonatal Nursing. - : Elsevier BV. - 0884-2175 .- 1552-6909. ; 38:3, s. 280-289
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Tidskriftsartikel (refereegranskat)abstract
- To describe new fathers' satisfaction with postnatal care after the introduction of a more family-centered model and to study factors related to fathers' overall satisfaction with postnatal care. Two cohorts of fathers who had a live-born baby during a 15 weeks period in 2004 and 2006. A Swedish hospital. Postnatal care options were traditional postnatal ward, early discharge, cocare at neonatal ward, and from 2006 a family suite on a hotel ward. Two hundred and eighty-four fathers whose babies were born in 2004 and 356 fathers whose babies were born in 2006. Data were collected using a questionnaire and descriptive statistical odds ratios with 95% confidence interval and logistic regression analyses were used. Six hundred and forty (64%) fathers completed the questionnaire. There was no improvement between the 2 years in satisfaction with the content of postnatal care, although fathers who stayed in the family suite on the hotel ward were more satisfied with the postnatal care over all. The following factors were most significant for predicting dissatisfaction with postnatal care: no support from staff, not being treated nicely, dissatisfaction with the environment, lack of medical check-ups for the mother, and visiting hours. A true family perspective should be applied in postnatal care and the new parents viewed as a family unit, not as medical cases only. Staff working in postnatal wards should be given the opportunity to involve fathers in postnatal care.
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| 21. |
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| 22. |
- Jensen, Patrik, et al.
(författare)
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Product development through lean design and modularization principles
- 2009
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Ingår i: Proceedings IGLC 17. ; , s. 465-474
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Konferensbidrag (refereegranskat)abstract
- Customers' demands regarding quality and cost efficiency caused the Swedish construction industry to increase its levels of prefabrication. However, the main focus has been on the structural design and production in the development of these new building systems, and very little attention has been devoted to customer needs and requirements. This has created a situation where ad hoc solutions have been introduced to adapt the building system to match the project requirements, causing problems in the production process with waste and quality problems as a result.Therefore, a development project was initiated with the goal to design a new building system for multi-story timber housing that could match the client needs and requirements. This paper describes how this development process was pursued using lean design methods and modularization principles. A multi-skilled development team worked for over 6 months in developing a technical and a process platform for a flexible building system. The study shows that it is evident that modularization principles can be used in order to develop flexible building systems that better can match the requirements from an individual project. From a set of rules, the architect can configure and design a unique building which enables the manufacturability of the building system and ensures a smooth assembly process of the prefabricated modules on the construction site.
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| 23. |
- Jensen, Patrik, et al.
(författare)
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Reducing complexity of customized prefabricated buildings through modularisation and it support
- 2008
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Ingår i: [Host publication title missing]. ; , s. 429-437
-
Konferensbidrag (refereegranskat)abstract
- Many companies in Sweden using prefabricating strategies are currently meeting the ever increasing customer requirements with ad-hoc solutions that do not fit their production system. This is causing bottlenecks and lower profit margins as a consequence. One solution to the problem is to re-engineer their building systems according to modularization principles used in the manufacturing industries, which have adapted their production to be able to meet mass-customization. This paper describes the first part in study of modularization of building systems and if methods used in themanufacturing industry can be adapted to the building industry. The Swedish construction industries using prefabrication strategies are mainly project oriented, and needs todevelop a more product oriented development process to benefit from the values that modularization can give.It is also obvious that it is impossible to introduce modularization methods used in manufacturing industries ifdesign requirements are incomplete or changing from project to project. It is therefore essential that theproduct owner owns the whole process as well. Varying customers’ demands can to some extent be handledusing modularization principles. However, we don’t believe that one solution fit’s all; therefore it is essential to target a specific segment of the market. The cost for the development of such modularized building systemfor the targeted segment of customer must be evaluated against the possible market share.
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| 24. |
- Jensen, Patrik, et al.
(författare)
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Reducing complexity of customized prefabricated buildings through modularization and IT support
- 2008
-
Ingår i: CIB-W78. - : Universidad de Talca. - 9789563193619 ; , s. 429-437
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Konferensbidrag (refereegranskat)abstract
- Many companies in Sweden using prefabricating strategies, are currently meeting the ever increasing customer requirements with ad-hoc solutions that do not fit their production system causing bottlenecks and lower profit margins as a consequence. One solution to the problem has been to re-engineer their building systems according to modularization principles used in the manufacturing industries that have adapted their production to mass-customization. This paper describes the first part in study of modularization of building systems and if methods used in the manufacturing industry can be adapted to the building industry. Today the Swedish Construction Industries are mainly project oriented, and needs to go to a more product oriented development to benefit from the values that modularization can give. It is also obvious that it is impossible to introduce modularization methods used in manufacturing industries if design requirements are incomplete or changing from project to project. It is therefore essential that the product owner owns the whole process as well. Varying customers' demands can to some extent be handled using modularization principles. However, we don't believe that one solution fit's all; therefore it is essential to target a specific segment of the market. The cost for the development of such modularized building system for the targeted segment of customer must be evaluated against the possible market share.
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| 25. |
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| 26. |
- Jongeling, Rogier, et al.
(författare)
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A method for planning of work-flow by combined use of location-based scheduling and 4D CAD
- 2007
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Ingår i: Automation in Construction. - : Elsevier BV. - 0926-5805 .- 1872-7891. ; 16:2, s. 189-198
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Tidskriftsartikel (refereegranskat)abstract
- There is a great potential to improve the flow of resources through locations on construction sites, termed work-flow. Current activity-based scheduling techniques do not provide adequate support for the planning of work-flow due to practical and methodological reasons. Location-based scheduling techniques provide a promising alternative to activity-based scheduling techniques for planning of work-flow. However, neither location-based nor activity-based scheduling techniques provide users with insight in the spatial configuration of scheduled construction operations. A technique that can provide this insight is 4D CAD in which 3D CAD models are combined with data from construction schedules. This article presents a process method for the planning of work-flow by combined use of location-based scheduling and 4D CAD. We suggest that a location-based approach to 4D CAD can improve the usability of the 4D CAD models for work-flow analyses. In addition, the article suggests that 4D CAD can enhance the value of location-based schedules.
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| 27. |
- Jongeling, Rogier, et al.
(författare)
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Modelling and simulation of cast in place concrete construction using N-dimensions
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Product models have long been theoretical models within international research communities, but are now starting to be adapted in the construction industry. Product models are data models that can contain both product and process data, such as geometry and planning data. Their current use in construction is mainly limited to 3D graphics, but product models have many more than three dimensions. In this research project we developed and applied different dimensions of product models beyond their common, but limited, use in 3D. Development and implementation efforts in the project are mainly driven by the interests from a ready-mixed concrete supplier. Product modelling systems imply an object oriented approach to cast in place concrete construction, which is not object oriented as a result of the nature of the product. Product models that are used in the design process differ from models that are used for production simulations. These, and other conditions, pose a number of challenges. However, product models offer also a number of opportunities to cast in place concrete construction. Products and processes can be simulated virtually for example, thereby facilitating the decision-making process regarding the application of new or existing technologies that can improve the construction process. Product models can also be used to link or integrate product data, such as material specifications, casting sequences, etc. Based on these, mainly theoretically identified, possibilities and constraints, a number of dimensions of product models are developed and applied in practice to different case study projects. The following model dimensions are explored in the project:Traditional 2D drawings and documents are partly generated from 3D models and hyperlinked to these models. Various types of 3D models from different disciplines are created by using file-based data transfers and a collaborative client-server environment. Multiple production plannings are linked to 3D models resulting in 4D models. 5D cost estimation is developed by linking different 3D models to cost estimation hierarchies. Model use and configuration of material parameters by a ready-mixed concrete supplier provides an additional dimension to the use of product models.The different dimensions illustrate on the one hand the support for new and existing products and processes for cast in place concrete construction and show on the other hand the potential of product model use beyond 3D graphics. Advantages and possibilities can be identified for the ready- mixed concrete supplier in the different model dimensions and we believe that other actors in construction can do the same. When actors have identified benefits of product modelling for their own business process they might be more willing to participate in shared product model use in search of benefits for the project team as a whole.
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| 28. |
- Jongeling, Rogier, et al.
(författare)
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nD modelling in the development of cast in place concrete structures
- 2005
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Ingår i: Electronic journal of information technology in construction. - 1403-6835 .- 1400-6529. ; 10:4, s. 27-41
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish IT-stomme (IT-structure) project is a two year research project, which is aimed at applying product models in practice and developing modelling tools for cast in place concrete structures. Implementations and applications discussed in this paper are mainly driven by the interests from a ready mixed concrete supplier who identified product modelling as a threat and as an opportunity for its business process. A number of product model dimensions is discussed that result from combining different software applications. An example of a potential nth dimension of product model development and use is given, in addition to a product model's 2nd, 3rd, 4th and 5th dimension. The nth dimension is illustrated by integrating a product model with results from a program used to calculate the optimal drying process for concrete slabs. This paper concludes by discussing main challenges for the uptake of product models in practice in relation to findings and efforts from the IT-stomme project.
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| 29. |
- Jongeling, Rogier, et al.
(författare)
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Quantitative analysis of workflow, temporary structure usage, and productivity using 4D models
- 2008
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Ingår i: Automation in Construction. - : Elsevier BV. - 0926-5805 .- 1872-7891. ; 17:6, s. 780-791
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents time-space analyses of construction operations supported by quantitative information extracted from 4D CAD models. The application of 4D models is a promising approach to help introduce construction innovations and to evaluate construction alternatives. Current analyses of 4D models are mainly visual and provide project stakeholders with a clear, but limited, insight of construction planning information. This practice does not take advantage of the quantitative data contained in 4D models. We use two 4D models of an industry test case to illustrate how to analyze, compare, and present 4D content quantitatively (i.e., workspace areas, work locations, and distances between concurrent activities). This paper shows how different types of 4D content can be extracted from 4D models to support 4D-content-based analyses and novel presentation of construction planning information. We suggest further research aimed at formalizing the contents in 4D models to enable comparative quantitative analyses of construction planning alternatives. Formalized 4D content can enable the development of reasoning mechanisms that automate 4D-model-based analyses and provide the data content for presentations of construction planning information.
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| 30. |
- Jongeling, Rogier, et al.
(författare)
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Quantitative analysis using 4D models : an explorative study
- 2005
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Ingår i: First International Conference on Construction Engineering and Management. - : Korea Institute of Construction Engineering and Management. ; , s. 830-835
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Konferensbidrag (refereegranskat)
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| 31. |
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| 32. |
- Jongeling, Rogier, et al.
(författare)
-
VIPP : Visualization in Design and Construction
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of the VIPP project is to improve the efficiency and quality of the design review and production scheduling process by using VR models based on 3D models from the design process. Visualization is increasingly used in early stages of development projects to facilitate communication processes, but the use of these models during phases such as detailed design, planning and construction is very limited. It is time-consuming and complicated to keep a VR model up-to-date as a result of differences in data structures and formats between the 3D CAD applications and VR applications. The VIPP project aims to facilitate the transfer of 3D CAD models to VR applications, but the main objective is to set a true example for the practical use of 3D models by professionals in the construction industry. The VIPP project shows in a real construction project that VR models are beneficial for design review and construction scheduling purposes. By means of defining scenarios for the early and detailed design review process and for production scheduling purposes the project shows benefits that can be divided in: facilitation of the communication process with project stakeholders, increased process efficiency and higher quality of the design and construction process outcome. The VIPP project shows that the 3D design process is different from the traditional 2D design process, but not radically different. The time required to create 3D and 4D models for the industry case study project was surprisingly little. However, it was found that it is critical to define early and clearly in a project for what purposes the 3D models will be produced. IFC, a neutral exchange format for building model information, is used to capture and transfer graphical and non-graphical data from 3D CAD models to VR applications. An IFC interface was developed for two VR applications in the VIPP project, but is set up in such a way that other VR applications also can benefit from the developed IFC interface. The objective of the VIPP project was to keep the definition of use cases, requirements and processes concrete in order to maximize the practical applicability of the VIPP project for other professional users in the construction industry. The practical approach might have compromised the scientific level of the project work, but we believe that the concrete results from the VIPP project can stimulate the industry to start using 3D models and VR environments in real building projects.
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| 33. |
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| 34. |
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| 35. |
- Kahn, Robin, et al.
(författare)
-
Neutrophil-derived proteinase 3 induces kallikrein-independent release of a novel vasoactive kinin.
- 2009
-
Ingår i: Journal of immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 182:12, s. 7906-7915
-
Tidskriftsartikel (refereegranskat)abstract
- The kinin-forming pathway is activated on endothelial cells and neutrophils when high-molecular weight kininogen (HK) is cleaved by plasma kallikrein liberating bradykinin, a potent mediator of inflammation. Kinins are released during inflammatory conditions such as vasculitis, associated with neutrophil influx around blood vessels. Some patients with vasculitis have elevated plasma levels of neutrophil-derived proteinase 3 (PR3) and anti-PR3 Abs. This study investigated if neutrophil-derived PR3 could induce activation of the kinin pathway. PR3 incubated with HK, or a synthetic peptide derived from HK, induced breakdown and release of a novel tridecapeptide termed PR3-kinin, NH(2)-MKRPPGFSPFRSS-COOH, consisting of bradykinin with two additional amino acids on each terminus. The reaction was specific and inhibited by anti-PR3 and alpha(1)-antitrypsin. Recombinant wild-type PR3 incubated with HK induced HK breakdown, whereas mutated PR3, lacking enzymatic activity, did not. PR3-kinin bound to and activated human kinin B(1) receptors, but did not bind to B(2) receptors, expressed by transfected HEK293 cells in vitro. In human plasma PR3-kinin was further processed to the B(2) receptor agonist bradykinin. PR3-kinin exerted a hypotensive effect in vivo through both B(1) and B(2) receptors as demonstrated using wild-type and B(1) overexpressing rats as well as wild-type and B(2) receptor knockout mice. Neutrophil extracts from vasculitis patients and healthy controls contained comparable amounts of PR3 and induced HK proteolysis, an effect that was abolished when PR3 was immunoadsorbed. Neutrophil-derived PR3 can proteolyze HK and liberate PR3-kinin, thereby initiating kallikrein-independent activation of the kinin pathway.
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| 36. |
- Karlström, Annika, et al.
(författare)
-
Swedish caregivers’ attitudes towards caesarean section on maternal request
- 2009
-
Ingår i: Women and Birth. - : Elsevier BV. - 1871-5192 .- 1878-1799. ; 22:2, s. 57-63
-
Tidskriftsartikel (refereegranskat)abstract
- Background Caesarean section (CS) is not an option that women in Sweden can chose themselves, although the rise in CS rate has been attributed to women. This study describes obstetricians’ and midwives’ attitudes towards CS on maternal request. Methods A qualitative descriptive study, with content analysis of 5 focus group discussions where 16 midwives and 9 obstetricians participated. Results The overarching theme was identified as “Caesarean section on maternal request—a balance between resistance and respect”. On the one hand, CS was viewed as a risky project; on the other hand, request for a CS was understood and respected when women had had a previous traumatic birth experience. Still, a CS was not really seen as a solution for childbirth related fear. Five categories were related to the theme. Overall, our findings indicate that caregivers blamed the women for the increase, they considered the management of CS on maternal request difficult, and they suggested preventive methods to reduce CS and means to strengthen their professional roles. Key conclusions and implication for practice Both midwives and obstetricians considered the management of CS on maternal request difficult, and the result showed that they balanced between resistance and respect. The result also showed that the participants stressed the importance of professionals advocating natural birth with evidence-based knowledge and methods to prevent maternal requests. Ongoing discussions among health professionals on attitudes and practice would strengthen their professional roles and lead to a decrease in CS rates in Sweden. Background: Caesarean section (CS) is not an option that women in Sweden can chose themselves,although the rise in CS rate has been attributed to women. This study describesobstetricians’ and midwives’ attitudes towards CS on maternal request. Methods: A qualitative descriptive study, with content analysis of 5 focus group discussions where16 midwives and 9 obstetricians participated. Results: The overarching theme was identified as ‘‘Caesarean section on maternal request–—abalance between resistance and respect’’. On the one hand, CS was viewed as a risky project; on theother hand, request for a CS was understood and respected when women had had a previoustraumatic birth experience. Still, a CS was not really seen as a solution for childbirth related fear.Five categorieswere related to the theme.Overall, our findings indicate that caregivers blamed thewomen for the increase, they considered the management of CS on maternal request difficult, andthey suggested preventive methods to reduce CS and means to strengthen their professional roles. Key conclusions and implication for practice: Both midwives and obstetricians considered the
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| 37. |
- Kühn, Ingolf, et al.
(författare)
-
MACIS: Minimisation of and Adaptation to Climate Change Impacts on BiodiverSity
- 2008
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Ingår i: GAIA. - 0940-5550. ; 17:4, s. 393-395
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Tidskriftsartikel (refereegranskat)abstract
- The recently finished EU funded project MACIS reviewed observed and projected climate change impacts on biodiversity. It assessed mitigation and adaptation options. It also reviewed and developed methods to assess future impacts of climate change on biodiversity including the identification of policy options to prevent and minimise these impacts.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
- Lu, Weizhuo, et al.
(författare)
-
A continuous flow simulation model for probability repetitive projects
- 2009
-
Ingår i: Proceedings of 5th Nordic Conference on Construction Economics and Organisation. - Reykjavik : University of Reykjavik. - 9789979983200
-
Konferensbidrag (refereegranskat)abstract
- Continuous flow is one of the main focuses of scheduling repetitive projects. Construction practitioners and researchers have proposed approaches to maintain continuous flows. However, many of these approaches only consider deterministic activity durations or have some other methodological limitations. Accordingly, a continuous flow simulation model is presented in this paper in order to overcome aforementioned limitations. The proposed model integrates simulation and buffering to consider the probability of activities durations and for proper sizing of buffers. Instead of having the same activity duration distribution on different units as is common, the proposed model allows for different activity duration distribution between units. The proposed model is tested and validated on a case study and the results show that the model can provide practical contributions in scheduling that effectively maintain continuous flow for probability repetitive project. Possible further research directions in this regard are also discussed in the paper.
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| 42. |
- Lundqvist, Joakim, et al.
(författare)
-
A probability study of finite element analysis of near surface mounted carbon fiber reinforced polymer bonded to reinforced concrete
- 2007
-
Ingår i: Fiber-Reinforced Polymer Reinforcement for Concrete Structures. - Patras : FRPRCS-8 Symposium Secretariat. - 9789608969100
-
Konferensbidrag (refereegranskat)abstract
- A structure is typically designed for a long life and it is probable that the demands on it change over time, e.g. carry larger loads or fulfill new standards. The structure might also have been exposed to a harsh environment leading to a degradation of its structural capacity. These reasons, and more, may lead to a need for strengthening the structure. Strengthening of reinforced concrete structures with carbon fiber reinforced polymers (CFRP) has been shown to be a very effective and advantageous retrofitting technique. The weight-to-strength ratio and resistance to corrosion are some of the advantages. Several different strengthening systems are available with CFRP and a relatively new technique is the near surface mounted reinforcement (NSMR) method. As opposed to externally mounted strengthening systems, NSMR is composed of sawing a groove in a concrete member, applying an adhesive in the groove and inserting a CFRP bar. Although the idea of embedding reinforcing tendons in existing structures has been present for several decades [1], acceptance of the method has only been possible with the emergence of the FRP material. As NSMR comprise of the properties and advantages of an ordinary FRP strengthening system, e.g. plates, it also has the benefit of being embedded in the concrete. This means better protection against impact, fire, abrasion and a natural resistance to peeling stresses. Strengthening of concrete members with NSMR have been reported by e.g. [2], [3], [4], and [5]. For NSMR, or indeed for most FRP strengthening techniques, the bond between the concrete and the strengthening material is the most important issue. This is where the transfer of stresses takes place to realize full composite action. The behavior of strengthened reinforced concrete is quite complex and an approach to investigate this is to utilize the finite element (FE) method. Many numerical analyses of reinforced concrete strengthened with CFRP using the FE method have been carried out in recent years. These concern primarily studies of plate bonding though there are a few studies of bonding of NSMR. In [6], concrete beams are strengthened with plates and the analytical shear and peeling stresses are compared with a linear finite element (FE) analysis. Several authors, e.g. [7], have emphasized that sufficiently small elements must be used in a FE analysis to accurately describe stress distributions, particularly at the end of a bonded plate. Teng et al, [8], make further refinement of the FE mesh and examine the interfacial stresses in reinforced concrete beams bonded with a soffit plate. A concern for the element size where stress singularities occur was also raised. Nonlinear FE analyses of reinforced concrete strengthened with NSMR are performed in [3], [4], [5], and [9]. The common failure mode of a strengthening system with plates is in the outermost concrete layer close to the adhesive. This has been reported in many papers, e.g. [9]. The failure mode for NSMR is more complex. It spans from being a failure in the adhesive close to the FRP bar, i.e. pure pullout, to the concrete layer close to the adhesive, as for FRP plates but with the difference that more concrete is dislodged. In between, a mixed mode of failure is present with cracks in both the adhesive and the concrete. Where the failure occurs is determined by geometrical and material parameters. The thickness of the adhesive, the position of the bar in the adhesive, and the bonding length are possible geometrical parameters. Material parameters are the modulus of elasticity and Poisson's ratio of the concrete, adhesive and the FRP, and of course the tensile strength of the concrete and adhesive. Also, the configuration and the properties of the internal reinforcement may determine the failure mode. To study the bond behavior of reinforced concrete strengthened with NSMR, a test for CFRP bar pullout was devised. This is illustrated in Figure 1 and is reported in [10]. The concrete beam has a minimum amount of reinforcing steel not shown in the drawing. In this paper, the pullout of a rectangular NSMR CFRP bar bonded to reinforced concrete is studied by a finite element analysis in the linear elastic domain. Also, a Monte Carlo simulation, with the FE model incorporated, is carried out with the purpose of determining which geometrical and material parameters that are the most important for where the tensile strength is attained; in the adhesive or the concrete. The following simplifications have been made in this study; all materials are considered as isotropic and linear elastic, and the FE model utilizes symmetry.
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| 43. |
- Lundqvist, Joakim, et al.
(författare)
-
Numerical analysis of concrete beams strengthened with CFRP : a study of anchorage lengths
- 2005
-
Ingår i: Proceedings of the International Symposium on Bond Behaviour of FRP in Structures. - : International Institute for FRP in Construction. ; , s. 239-246
-
Konferensbidrag (refereegranskat)abstract
- The advantages of Fibre Reinforced Polymer (FRP) strengthening have been shown time and again during the last decade. All over the world several thousand structures have been retrofitted using FRP. Buildings and civil structures usually have a very long life and it is not uncommon that the demands on the structure change with time. The structures may have to carry larger loads at a later date or fulfil new standards. In extreme cases, a structure may need repair due to an accident, or due to errors made during the design or construction phase. To guarantee the function of the strengthening properties, anchorage of the FRP is essential. Without sufficient anchorage lengths, full utilization of the strengthening material cannot be achieved, leading to possible premature failure. In this paper, experimental work and numerical analyses of three different Carbon Fibre Reinforced Polymer (CFRP) strengthening techniques have been carried out. The techniques are externally bonded plates, sheets and the use of Near Surface Mounted Reinforcement (NSMR). The aim is to find a critical anchorage length, where a longer anchorage length does not contribute to the load bearing capacity. Three different anchorage lengths have been investigated; 100, 200 and 500 mm. The finite element program ABAQUS has been used for the numerical study. The results show that a critical anchorage length exists for plates and sheets as well as for NSMR. However, the present study also shows that an exact critical anchorage length may be difficult to estimate, at least with the present test set-up. Further tests and investigations of the constitutive model for the concrete are needed.
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| 44. |
- Norberg, Håkan, et al.
(författare)
-
A process model for construction synchronisation using time-space planning methods and Field Force Automation
- 2008
-
Ingår i: CIB W78 25th International Conference on Information Technology in Construction. - : Universidad de Talca. ; , s. 91-102
-
Konferensbidrag (refereegranskat)abstract
- This paper explores a proposed process model for construction synchronisation. The aim of the paper is to show the potential of working according to the Last Planner System of production and control by combining time-space planning methods and Field Force Automation. In addition, the paper aims to show the benefits of working with real time support regarding taking control actions in the schedule and to collect data for follow-up analysis. The paper first provides a background of the research and a description of the various methods and tools used in the process model. A process model is proposed based on the last planner and control system for the implementation of a new ICT tool with the purpose to enhance, planning and control in order to enhance construction synchronisation. It is concluded that site managers needs tools to change their view of planning from static view of the schedule which can be revised once or twice per project to the view that the schedule is a total dynamic instrument to be used to develop prognosis and measure for avoiding waste and delays in the realisation phase of the construction project. The paper is concluded with suggestions for how the method can be further developed and improved.
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| 45. |
- Norberg, Håkan, et al.
(författare)
-
Byggsynkronisering
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten redovisar de resultat som hittills framkommit i ett ERABUILD-projekt där avsikten är att skapa industrialiserade processer för definition, utformning, byggande och fastighetsförvaltning som väsentligt kan effektivisera byggande och förvaltning av fastigheter över hela livscykeln. Målet med den svenska delen är att definiera en framtida industrialiserad byggprocess som är stödd av ett synkroniserat flöde av information, resurser, material och aktiviteter till byggplatsens olika produktionsställen. Hypotesen är att platsknutna planeringsmetoderna som Line of Balance och 4D tillsammans med en robust produktionsstyrningsmetod kan skapa arbetsscheman som kan genomföras med tillräcklig förutsägbarhet. Detta är nödvändigt för att kunna skapa bra och effektiva försörjningskedjor. Mobila verksamhetssystem är en lämplig teknologi för att kunna understödja ett sådant synkroniserat byggande. För att säkerställa en öppen tillgång till den gemensamma bygginformationsmiljön (VBE) kommer tekniken med standardiserade Web Services att testas för att koppla ihop applikationer som kan stödja ett synkroniserat byggande.I Etapp I av projektet har produktionsprocessen för en typisk byggplats kartlagts där informations- och materialflöden samt användning av gemensamma resurser nödvändiga för genomförandet av olika produktionsaktiviteter definierats för att utveckla en byggplatsanpassad logistikmodell. Applikationer och metoder för planering och styrning samt strategier och mått för byggplatsens försörjningskedjor av information, material och komponenter har identifierats. I Etapp II, har valda delar av modellen att jämförts och utvärderas mot traditionella metoder i ett pågående byggprojekt, (NCC:s projekt kvarteret Rådjuret i Luleå samt Solberga Torg). Framtagna metoder med stöd av valda applikationer har demonstreras i en avgränsad del av projektet. Idag implementeras 3D projektering i stor skala i den svenska byggbranschen. Detta har lett till bättre samordning mellan olika discipliner och mindre antal kollisioner som måste lösas på plats. I nästa steg kommer en övergång till bygginformationsmodeller att ske (BIM) där informationen kommer att integreras mellan olika aktörer och skeenden i byggprocessen. En sådant naturligt steg är att integrera projektering och produktion där stora värden kan sparas om BIM modellen kan användas för inköp, planering och genomförandet i produktionsprocessen. En demonstrationsmiljö har byggts upp med en modellserver, en BIM Collaboration Hub, för att hantera IFC-filer som definierar byggnaden och andra filtyper som används i olika affärsprocesser. De olika bygg- och installationsdelarna kan läsas in med sina versioner från CAD-system i IFC-formatet och därefter knytas till annan information som t ex krav och tidplaneaktiviteter. Arkitekturen ger en flexibel lösning där företag kan samverka med hjälp av olika överföringsmetoder - filöverföring, tjänster som anropas och inmatning via ett grafiskt användargränssnitt. Den processmodell som utvecklats i inVBE projektet och som utgör viktig del i Håkan Norbergs lic-avhandling (se referenslistan) skapar bättre förutsättningar för beredning/koordinering, synkronisering, rapportering och uppföljning av produktionen på byggarbetsplatserna. Vid projektets slutpresentation var intresset stort från flera byggföretag att prova och utvärdera det nya arbetssättet och de nya verksamhetsstödjande applikationerna. Ambitionen är därför att tillsammans med intresserat byggföretag med lämpligt byggprojekt ansöka om SBUF medel för att genom fältprov utvärdera om förväntade kvalitets- och produktivitetsförbättringar erhålls i verkligheten.
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| 46. |
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| 47. |
- Nordin, Steven, et al.
(författare)
-
Chemosensory perception and event-related potentials in self-reported chemical hypersensitivity
- 2005
-
Ingår i: Int Journal of Psychophysiology. ; 55:2, s. 243-255
-
Tidskriftsartikel (refereegranskat)abstract
- Anormal chemosensory perception has been identified as a possible mechanism underlying odor intolerance, but research in this domain has yet been rather limited. The main objective of the present study was to investigate total perceived intensity, unpleasantness, sensory irritation, and cortical activity assessed with chemosensory event-related potentials (ERPs) for three concentrations of pyridine ranging from predominantly olfactory to trigeminal in activation. Results from 19 individuals with self-reported chemical hypersensitivity and 19 controls with self-reported normal chemical sensitivity show that the hypersensitive group, compared to controls, rated the pyridine stimuli to be more intense and unpleasant, and that these group differences increased with pyridine concentration. Sensory irritation was also the perceptual dimension found to correlate strongest with score on the chemical sensitivity scale. However, no group differences were found in ERP amplitudes or latencies. These findings suggest that self-reported chemical hypersensitivity (1) can be associated with anormal chemosensory perception, (2) may be more closely related to trigeminal function than to olfaction, and (3) has a neural basis at a higher cortical level than that captured by chemosensory ERPs.
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| 48. |
- Olofsson, Eva M, 1975-, et al.
(författare)
-
In vitro glucose-induced cataract in copper-zinc superoxide dismutase null mice
- 2005
-
Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835 .- 1096-0007. ; 81:6, s. 639-646
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to evaluate the involvement of the superoxide radical in glucose-induced cataract using lenses from mice lacking the cytosolic copper-zinc superoxide dismutase (SOD1). Lenses from wild-type mice and SOD1 null mice were kept in organ culture with either 5.6 or 55.6 mM glucose for 6 days. The cataract formation was followed with digital image analysis and ocular staging. The lens damage was further quantified by analysis of the leakage of lactate dehydrogenase into the medium by the uptake of 86Rb and by determining the water content of the lenses. The formation of superoxide radicals in the lenses was assessed with lucigenin-derived chemiluminescence. Immunohistochemical staining for SOD1 was also performed on murine lenses. The SOD1 null lenses exposed to high glucose developed more cataract showed an increased leakage of lactate dehydrogenase and developed more oedema compared to the control lenses. At 5.6 mM glucose there was no difference between the SOD1 null and wild-type lenses. Staining for SOD1 was seen primarily in the cortex of the wild-type lens. This in vitro model suggests an involvement of the superoxide radical and a protective effect of SOD1 in glucose-induced cataract formation.
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| 49. |
- Olofsson, Jörgen, et al.
(författare)
-
Effects of human land-use on the global carbon cycle during the last 6,000 years
- 2008
-
Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 17, s. 605-615
-
Tidskriftsartikel (refereegranskat)abstract
- Humanity has become a major player within the Earth system, particularly by transforming large parts of the land surface and by altering the gaseous composition of the atmosphere. Deforestation for agricultural purposes started thousands of years ago and might have resulted in a detectable human influence on climate much earlier than the industrial revolution. This study presents a first attempt to estimate the impact of human land-use on the global carbon cycle over the last 6,000 years. A global gridded data set for the spread of permanent and non-permanent agriculture over this time period was developed and integrated within the Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ-DGVM). The model was run with and without human land-use, and the difference in terrestrial carbon storage was calculated as an estimate of anthropogenic carbon release to the atmosphere. The modelled total carbon release during the industrial period (A.D. 1850–1990) was 148 gigatons of carbon (GtC), of which 33 GtC originated from non-permanent agriculture. For pre-industrial times (4000 B.C.–A.D. 1850), the net carbon release was 79 GtC from permanent agriculture with an additional 35 GtC from non-permanent agriculture. The modelled pre-industrial carbon release was considerably lower than would be required for a substantial influence on the climate system.
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| 50. |
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