| 51. |
- Puñal Pereira, Pablo
(författare)
-
Efficient IoT Framework for Industrial Applications
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of low-power wireless sensors and actuators with networking support in in-dustry has increased over the past decade. New generations of microcontrollers, new hardware for communication, and the use of standardized protocols such as the Internet Protocol have resulted in more possibilities for interoperability than ever before. This in-creasing interoperability allows sensors and actuator nodes to exchange information with large numbers of peers, which is beneficial for creating advanced, flexible and reusable systems.The increase in interoperability has resulted in an increase in the number of possible attacks from malicious devices or users. For this reason, the use of encryption techniques to protect client and server communications has become mandatory. However, even with state-of-the-art encryption mechanisms, there is no protection that can control access to each particular service with fine-grained precision. The nodes within an industrial network of wireless sensors and actuators are resource-constrained embedded devices, and increasing interoperability therefore requires a higher level of computation capabil-ities. The nodes’ intrinsic limitations of memory and processing exert an adverse effect on power consumption and communication delays, resulting in a shorter battery life-time. Therefore, the standard computing solutions for Internet communications are not directly applicable, and new mechanisms to achieve security, scalability, dependability, interoperability and energy efficiency are needed.Sensor and actuator networks can transmit sensed data, but they also offer access to the actuators. Such accesses, presumably provided via services, require an access protection scheme. For this reason, the use of access control mechanisms is mandatory. Access control assists in the creation of customized services and access policies. These access policies can isolate access permissions to devices with different roles, such as production and maintenance.The main contribution of this thesis is a novel, efficient IoT framework for industrial applications, including design, implementation, and experimental validation. The frame-work includes features for communication protection, authentication, fine-grained access control, zero-configuration networking, and run-time reconfiguration. These technologies and their corresponding energy consumption data clearly demonstrate the feasibility of integrating a battery-operated IoT concept into a functional System of Systems. The provided data also pinpoint the most critical areas for improvement.
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| 52. |
- Qin, Hao
(författare)
-
Multiresolution Continuum Theory and Dislocation Density Based Constitutive Relations
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In classical description, the mechanical state of a material point depends on the variables defined at this point solely. It can integrate and catch some aspects of the material’s microstructure by conventional homogenization method. The application of the conventional continuum assumption results in a simplified description of the system which makes the large scale simulation of the material more efficient but at the expense of a loss of information at small length scales. Localization is a phenomena where a large degree of deformation occurs in highly concentrated regions. The conventional continuum theory with strain softening can not give the convergent solution as the size of the localization zone is completely determined by the mesh discretization. The multiresolution continuum theory (MRCT) is a higher order continuum theory where additional kinematic variables supplementing the conventional macroscopic displacement field are added to account for deformations at several distinct length scales. The direct inclusion of the length scale parameters in the material’s constitutive equations remedies the convergence problem. In crystalline materials the initiation of plastic flow and subsequent permanent plastic deformation is attributed to the presence and movement of dislocations and also the interactions between the dislocation themselves and different kinds of obstacles, inclusions, second phase particles and grain boundaries etc. Some of these defects can alsolead to damage initiation in the materials. For example, the stresses developed at the dislocation pile-ups contribute to the initiation of the microvoids and microcracks. A dislocation density based damage model has been developed and combined with a physically based flow stress model. They are calibrated and validated for 316L stainless steel at different temperatures and strain rates. These models have been implemented into the macroscopic material description of the MRCT element.
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| 53. |
- Qureshi, Asif, 1986-
(författare)
-
Co-disposal of waste rock and lignite fly ash to mitigate the environmental impact of coal mining
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Waste rocks (WRs) from coal mining and fly ash (FA) from coal combustion were studied to determine the potential of the WRs to generate AMD, FAs to neutralise it and estimate their impacts on environment. The ultimate goal was to develop a methodology based on co-disposal to mitigate the environmental problems associated to both wastes. Two methods for co-disposal were tested: i) Mixing WRs and FAs and ii) covering WRs with FAs.WRs were sampled from the Lakhra coal mines in Pakistan (PK), which has an estimated coal reserves of 1.3 Btonne, varying from lignite to sub-bituminous quality. The FA was sampled from a power plant utilising coal from Lakhra coal mines and is situated in close vicinity (15km) of the mine site. For comparative purposes a bituminous FA from Finland (FI) and biomass FA from Sweden (SE) were also characterised.The WRs and FA samples were characterised by mineralogical and geochemical methods. Besides organic material (coal traces), quartz, pyrite, kaolinite, hematite, gypsum and traces of calcite, lime, malladerite, spangolite, franklinite and birnessite were identified in WRs by XRD. The major elements Si, Al, Ca and Fe were in the range (wt. %) of 8 – 12, 6 – 9, 0.3 – 3 and 1 – 10, respectively, with high S concentrations (1.94 – 11.33 wt. %) in WRs. The AMD potential of WRs ranged from -70 to -492 kg CaCO3 tonne-1.All FAs contained quartz, with iron oxide, anhydrite and magnesioferrite in PK, mullite and lime in FI and calcite and anorthite in SE. The Ca content in SE was 6 and 8 times higher compared to PK and FI, respectively. FAs were enriched in As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn compared to continental crust. The acid neutralising potential of PK was equivalent to 20 kg CaCO3 tonne-1 compared to 275 kg CaCO3 tonne-1 (SE) and 25 kg CaCO3 tonne-1 (FI).During the period of 192 days in weathering cell experiments (WCE), the pH of leachates from most acidic WRs was maintained from 1 to 2.5, whereas, the less acidic WRs produced leachates of mildly acidic (2.7) to neutral (7.3) pH. The leachates from very acidic WRs ranged in the concentrations of Fe, SO24− and Al from mg L-1 to g L-1.The samples were subjected to column leaching experiments (CLE) in which mixture (FA:WR; 1:3) and cover (FA:WR; 1:5) cases were mimicked (with 10mm particle size) and effects of particle size (2, 5 and 10mm) on element leaching were studied.Despite having the lowest acid-neutralisation potential compared to FI and SE, co-disposal of PKFA as mixture readily provides acid buffering minerals, resulting in better start-up pH conditions and leachate quality. However, acidity produced by secondary mineralisation contributes towards the acidification of the system, causing stabilisation of pH at around 4.5−5. Secondary mineralisation (especially Fe- and Al-mineral precipitation) also removes toxic elements such as As, Pb, Cu, Zn, Cd, Co, Ni and Mn, and these secondary minerals can also buffer acidity when the pH tends to be acidic.In contrast, the pH of the leachates from the PKFA cover scenario gradually increased from strongly acidic to mildly acidic and circumneutral along with decrease in EC and elemental leaching in different WRs. Gradually increasing pH can be attributed to the cover effect, which reduces oxygen ingress, thus sulphide oxidation, causing pH to elevate. Due to the fact that pH~4–5 is sufficient for secondary Fe- and Al-mineral precipitation which also removes toxic elements (such as Cd, Co, Cu, Zn and Ni) by adsorption and/or co-precipitation, the FA cover performs well enough to achieve that pH until the conclusion of the CLE. However, due to the slower reactivity of the buffering system (additional to the initial flush-out), leaching in the beginning could not be restricted.The co-disposal of FA as cover and/or mixture possesses potential for neutralisation of AMD and improving leachate quality significantly. Particle size of the WRs affected the leaching of the sulphide related elements (such as Fe, S, Zn, Co, Cr, Cu, Mn and Ni) in CLE and WCE. Experiments with ≤1mm particle size constantly produced acidic and metal laden leachates. Co-disposal of FA and WRs as cover and mixture need to be investigated on pilot-scales before full-scale application.
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| 54. |
- Rodriguez, Juan
(författare)
-
Effect of Physical Weathering on Mechanical Properties of Tailings
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The mining activity produces minerals to supply to the modern society with commodities. During the ore refining process large amounts of tailings are generated as waste. Tailings are the result of crushing and wet milling, typically in the size range of sand to silt and angular in shape. Tailings are in general deposited in tailings dams for permanent storage. Tailings dams are usually considered as walk-away solutions and needs to be designed and constructed to be safe in a long time perspective. Several incidents around the world have occurred in tailings dams both during construction and operation and after closure of the activities. The consequences of the failures may be fatal to the local society and harm the surrounding environment. Considering the consequences of failures and relatively few studies on tailings properties in a long term perspective there is a need for research. As a consequence of the operation and raising procedures of tailings dams, the conditions in the tailings dams could be considered to be dynamic in a longer perspective. Grain size distribution, formation of layers, pore pressures and stress states are continuously changing during the operation. Tailings may be susceptible to weathering in the deposit environment. The change of these factors needs to be addressed in the design of walk-away solutions. In this work image analysis, oedometer-, triaxial-, direct shear- and attrition tests has been carried out to study the tailings particle influence on fundamental geotechnical properties in a case study. The parameters have been compared to similar-sized natural materials. The effect of loading and physical weathering has been studied and evaluated by image analysis and sieving. The comparative test by natural materials shows that tailings, probably due to the irregular shape, initially arranges in looser interparticle structures. The looser arrangement makes tailings fills more susceptible to settlement compared to natural deposits in the same size range. The two most identified factors affecting the tailings on a particle level was the type of physical weathering and grain size. Static load, shearing and milling decreases the grain size but the effect on the individual particles were different. Large grains tend to maintain the shape or get rounded by physical degradation and finer grains get more angular by milling but rounded by shearing. An attempt has been done to predict the effect on friction angle as a function of angularity, grain size and initial void ratio. The increase in angularity in the model suggests an increase in the friction angle and so the increase of regularity (decrease of elongation relation). However the reduction of size will either reduces or compensates this effect. More studies are needed to verify this.
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| 55. |
- Sany, Seyed Mohammad Khoshkhoo
(författare)
-
Chalcopyrite (Bio)leaching in Sulphate Solutions : An Investigation into Hindered Dissolution with a Focus on Solution Redox Potential
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chalcopyrite (CuFeS2) is the most abundant and the most economically important copper mineral. Increasing worldwide demand for copper accompanied by exhaustion of copper resources necessitate the development of new processes for treating lower-grade copper ores. Heap (bio)leaching of copper oxides and secondary sulphides (covellite (CuS) and chalcocite (Cu2S)) is a proven technology and a convenient process nowadays. However, chalcopyrite is recalcitrant to leaching and bioleaching in conventional leaching systems in sulphate media. Slow dissolution of chalcopyrite is attributed to the formation of compounds on the surface of the mineral during its dissolution and is often termed “passivation” or “hindered dissolution”. There is still no consensus about the nature of the passivation layer. There are, however, four proposed candidates suggested in the literature: metal deficient sulphides, polysulphides, jarosite and elemental sulphur. This project was aimed to further investigate the chalcopyrite dissolution and its passivation under strictly controlled redox potential conditions. The leaching experiments of the aged and fresh chalcopyrite concentrate under identical conditions showed that copper dissolution was significantly lower from the aged concentrate. The common understanding of reductive leaching mechanism (i.e. higher recoveries at lower redox potentials) was not valid for aged concentrates. Aged concentrates gave steadily increasing recoveries with increased redox potential. The hindering effect exerted from the atmospheric oxidation products on the surface of the aged concentrates was found to be responsible for this behaviour. It was also shown that the reductive leaching mechanism would be beneficial in the presence of an active galvanic interaction. Experiments using a pyritic concentrate resulted in higher recoveries at low redox potential while the dissolution rates were similar at low and high redox potentials using a relatively pure concentrate. In addition, the effect of initial copper concentration had no influential effect on the leaching rates for possible industrial processes. Redox potential development during moderately thermophilic bioleaching experiments of a pyritic chalcopyrite concentrate and a relatively pure chalcopyrite concentrate were chemically/electrochemically mimicked in the absence of microorganisms. The copper recoveries in absence and presence of microorganisms were similar. In some of the abiotic experiments, jarosite precipitated due to a loss of control of the redox potential. However, presence of bulk jarosite did not hamper the copper recovery compared to the bioleaching experiments where there was no bulk jarosite formation. Bio-oxidation of elemental sulphur did not have a positive effect on the leaching behaviour compared to the abiotic experiments where bulk elemental sulphur accumulated. Isotopic fractionations of copper and iron during the bioleaching and abiotic experiments showed that regardless of presence or absence of microorganisms the copper and iron isotopes fractionation followed a similar trend and that such analyses could be used in natural systems as an indicator of the oxidation extent. Surface analyses using X-ray photoelectron spectroscopy (XPS) measurements revealed that common phases on the surface of the samples leached for different durations were iron-oxyhydroxides and elemental sulphur. The elemental sulphur on the surface of the samples was bound to the surface rigidly in a way that it did not sublimate in the ultra-high vacuum environment of the XPS spectrometer at room temperature measurements. Surface jarosite was observed in only one sample but no correlation between its presence and the hindered leaching could be made. It is proposed that iron-oxyhydroxides are the main precursor of chalcopyrite hindered dissolution in sulphate media where their inevitable formation entraps surface elemental sulphur resulting in a consolidated phase on the surface. It was shown that when suitable conditions are met, high copper recoveries can be obtained before the surface is finally hindered.
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| 56. |
- Schnabel, Stephan
(författare)
-
High Frequency Elastic Wave Emission Caused by a Single Elastohydrodynamically Lubricated Contact: Fundamental sources and Principles
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Elastohydrodynamically lubricated (EHL) contacts are fundamental for severalrotating machine elements. For example gears, rolling element bearingsand lubricated chain drives work due to the principle of EHL. All of these machineelements require maintenance and, as condition based maintenance hasincreased in industry, the need for monitoring techniques has also increased. Inorder to avoid incorrect condition indications, since the 60’s researchers haveimproved signal processing of existing monitoring tools and developed newtechniques as a complement to these existing tools. In the past two decadesacoustic emission has been identified as a new complementary tool for monitoringof rolling element bearings and investigated intensively by several researchgroups. However, most of the investigations were carried out at lowrotational speeds. Furthermore, most of the investigations used simple signalprocessing methods like activation counts (AC) or trend analysis of the rootmean square signal (RMS). One reason for using simple experimental conditionsand signal processing methods is the complexity of a rolling elementbearing itself. A rolling element bearing consists of several EHL contacts andeach contact has different operational conditions (film thickness, slide to rollratio, contact pressure, entrainment speed). The measured signal is the summationof all EHL contacts. This complexity is one reason why the high frequencyemissions of an EHL contact are still not fully understood. Therefore, an investigationof the acoustic emission of a single EHL contact was here carriedout within the framework of a PhD project.In this thesis simplified experiments were used to represent either a single EHLcontact or elements of an EHL contact. Both acoustic emissions of tensile testsand ball impacts on a solid plate were studied and analyzed with respect totheir significance for EHL contacts. For all investigations carried out in thisthesis an absolute calibration method developed by McLaskey and Glaser wasused. This calibration method was validated for boundary restricted systems,where a good agreement for zero frequencies was found, however, unsatisfying agreement was discovered for resonances of a boundary restricted system. Theinvestigation found elastic waves in boundary restricted systems consist of twofundamental types. Zero frequencies will be enhanced for cases were excitationsource and elastic wave are independent, while an interaction of sourceand elastic wave results in a pure resonance problem.Furthermore, the time dependency of acoustic emission signals was investigated.As mentioned previously most existing investigations are carried outat low and constant rotational speed. The dependency of acoustic emissionsignals and speed is reported in literature as well as difficulties with acousticemission measurements at elevated rotational speeds. By using ball impactswith different ball sizes and tensile tests with different displacement speeds thetime dependency was analyzed with respect to excitation time (contact time ofball impact) and event frequency (amount of dislocation movement and planeslip movements in a certain time frame). Thereby an indirect quadratic proportionalitybetween acoustic emission amplitude and contact time was found.This proportional relationship is also valid for RMS signals with short averagingwindows if system damping is low. For event frequency and RMS signalsthe results of the tensile tests suggest a direct proportional relationship.Furthermore, Hertzian and EHL contact impacts were studied and compared.Thereby it was observed that the overall amplitude of the signal increases forEHL contacts in comparison to Hertzian contacts. In addition the third zerofrequency disappears, which is most likely due to cavitation effects. Furthermore,the results show a shift of the first and second zero frequency towardshigher frequencies, which is caused by the localised deformation of EHL contactsas a result of the solidification of the lubricant. This behaviour of zerofrequencies was in line with simulation results. However, the agreement betweensimulation and measurement for the location of zero frequencies and thesignal amplitude was not satisfying. This mismatch was most likely caused bythe assumption of the global contact force acting at a single point, causing aperfect elastic deformation in the simulation. Additionally, for the findings regardingzero frequencies, a change in the excitation of resonances above thefirst zero frequency in boundary restricted systems was also found, comparingHertzian and EHL impacts.Finally, full scale tests on a complete rolling element bearing were carried outduring the PhD project to validate findings of the single contact experiments.Magnetite contaminated rolling element bearings and their acoustic emissionsignals were investigated with respect to the use of sulfur additives, contaminationand rotational speed. These tests were executed at varying speed forsingle measurements and constant speed for continuous measurement recording. The results of the full scale tests showed good agreement with previousresults of the component tests, such as bouncing ball and tensile tests. Transientforces are the main source of signals for well lubricated rolling elementbearings or bearings at high rotational speed, while acoustic emission signalsof contaminated bearings at low rotational speed were dominated by plasticdeformation signals. Furthermore, it was found that sulfur additives reducethe plastic deformation signal by up to 70% in comparison to contaminatedbearings lubricated with plain grease.
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| 57. |
- Shirzadegan, Mohammad
(författare)
-
Elastohydrodynamic Lubrication of Cam and Roller Follower Applications : Fast and Reliable Predictions of Friction
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modelling and simulation in tribology, and more specifically of friction in lubricated contacts, has gained increasing attention over the past years. In a lubricated contact, the dissipation of energy is due to the relative motion of the mating surfaces and arise due to direct contact as well as shearing of the lubricant film. The presence of a thin lubricant film is crucial for the operation of various machine elements, e.g., for the concentrated contact between the rolling element and the raceway in a bearing. The contact in this type of applications is typically exhibiting substantial elastic deformation which together with hydrodynamics governs the formation of the lubricant film. Therefore, these type of contacts are said to operate in the Elastohydrodynamic lubrication (EHL) regime. An elastohydrodynamically lubricated contact can be classified as line, circular or elliptical. The line contacts can also represent a truncated ellipse or be of finite length. The line contact that appears between two cylindrically shaped bodies of infinite length does of course not exist in reality. It does, however, constitute an important type of simplification of the contact in real applications where the contact length perpendicular to direction of motion is comparatively large. The reason for this is that it permits a 2D-model for the flow and there are analytical solutions, at least in the most elementary cases. The circular and the fully elliptical contacts are more complicated. The case where the surfaces are fully separated by the lubricant film has, however, been addressed by many researchers and there are quite a few papers reporting numerical predictions validated by experimental data. The finite length line and truncated elliptical contact are even more challenging, but these are also the only physically reasonable models for EHL contacts exhibiting edge effects, created by profiled rollers or in cases where the contact ellipse becomes larger than the physical size of the contacting elements.This thesis presents the development of a fully coupled model that can be used to predict the pressure build-up and lubricant film formation in finite length line contacts. More precisely, in EHL contacts where the rolling element have profiled edges (fillets) and the surface of the counteracting element is wider than the roller, e.g., in a typical cam-roller follower contact. Hereafter this type of contact will be referred to as a 'finite EHL line contact'. The numerical analyses, conducted with the present model, were designed so that generic knowledge about friction in cam-roller follower applications would be generated, but also to provide for the development of a semi-analytical for fast and efficient estimation of friction.There are quite a few parameters that affect the friction in EHL contacts and it is already a challenge to include the most basic ones in the model. The most advanced and sophisticated models are very complex with millions of degrees of freedom and are, therefore, not yet feasible to conduct parametric studies with. The extreme conditions associated with EHL, i.e., nm thin films, with phase transition from liquid to solid, GPa pressure, temperature increase with considerable implications on lubricant flow and surface chemistry, etc., makes it even more difficult to model these systems. When modelling a cam-roller follower application, which typically results in a finite length EHL line contact, the size and geometry of the contacting parts further complicates modeling of EHL. The main objective, with this thesis project, was to design a low degree of freedom model that can be employed in a multibody dynamics model, to estimate EHL friction in milliseconds and yet capturing the most important features of a lubricated contact including edge effects. This resulted in a semi-analytical low degree of freedom (LDOF) model taking thermal effects into account and that include lubricant shear thinning and compressibility, in order to estimate the viscosity and volume of the lubricant.In addition, this LDOF model was extended to perform friction prediction covering the mixed lubrication regime where colliding asperities partially influence shearing of the lubricant. The extended, mixed lubrication LDOF, model was utilized to perform friction predictions covering a range of operating conditions, which were also covered in an experimental investigation using a ball-on-disk test device. The results turned out to compare well, suggesting that the model established in this project, is a usable tool that can be employed when designing lubricated devices and that it constitutes a suitable foundation for further developments.
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| 58. |
- Sirkka, Marianne
(författare)
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Hållbart förbättringsarbete med fokus på arbetsterapi och team : Möjligheter och utmaningar
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hälso-och sjukvården (HoS) har skyldighet att bedriva en evidensbaserad verksamhet baserad på bästa tillgängliga vetenskapliga kunskap, professionens expertkunnande, patienternas erfarenheter och tillgängliga resurser. Förbättringsarbeten pågår för att uppnå bästa möjliga HoS men kunskapen om hur hållbara förbättringar uppnås är fortfarande begränsad. Det övergripande syftet med denna avhandling var att bidra till ökad kunskap om möjligheter och utmaningar vid långsiktigt förbättringsarbete med fokus på arbetsterapi och team. Avhandlingens fyra delarbeten baseras på studier av långsiktiga förbättringsarbeten vid två olika enheter. Studie I syftade till att beskriva utvecklingen av ett långsiktigt förbättringsarbete som baserades på en arbetsterapeutisk praxis modell, Occupational Therapy Intervention Process Model (OTIPM). Data utgjordes av olika typer av dokument (435sidor) från 2001-2013 som var relaterade till förbättringsarbetet och analyserades med mönsterjämförelser (pattern matching). I Studie II var syftet attutforska arbetsterapeuters erfarenheter av ett långsiktigt förbättringsarbete. Data utgjordes av semistrukturerade intervjuer med 19 arbetsterapeuter i tre fokusgrupper år 2006 och uppföljande fokusgruppsintervjuer år 2011. Materialet analyserades med kvalitativ innehållsanalys. Studie III syftade till att identifiera stödjande och hindrande element vid långsiktigt förbättringsarbete med stöd av det implementeringsteoretiska ramverket, Promotion Action on Research Implementation in Health Services (PARiSH). Data från fokusgruppintervjuer analyserades först med manifest innehållsanalys med ramverket som raster och vidare med en latent innehållsanalys. Studie IV syftade till att utforska ett tvärprofessionellt teams erfarenheter av att implementera en teamorienterad och evidensbaserad behandlingsmodell Mentaliseringsbaserad terapi (MBT). Data utgjordes av återkommande fokusgruppsintervjuer som analyserades med en metod för jämförelseav kvalitativ data, inspirerad av Grounded Theory. Resultatet av studie I visar på sju olika faser i det långsiktiga förbättringsarbetet. Faserna representerar tre huvudmönster i processen och beskriver olika tillvägagångssätt för omorientering, etablering och långsiktig hållbarhet. I studie II beskrivs det långsiktiga förbättringsarbetet som en resa mot en hållbar ochevidensbaserad praktik. Resultatet visar på en förändringsresa med tre sammanflätade perspektiv; 1) omvandla tankar och handlingar genom återkommande kollegial reflektion, 2) hantera den upplevda dubbelheten av förändring, 3) utveckla en ömsesidigt professionell kultur. I studie III framkommer att samtliga element i ramverket PARiSH (evidens, kontext och facilitering) hade övervägande höga värden vilket indikerar en lyckad implementering. Vidare framkommer att den nya professionsinriktade kunskapen ansågs ha hög evidens. Den starka kollegiala kulturenvärderades högt och underlättade fortsatt förbättringsarbete trots olika utmaningar och stressmoment över tid. Resultatet av Studie IV beskriver implementeringen av den evidensbaserade och teamorienterade modellen, MBT som en interdisciplinär process med teoretiska, praktiska, emotionella och reflekterande komponenter. Det interprofessionella teamarbetet identifierades som en drivkraft för hållbar implementering och den reflekterande komponenten framstod som avgörande för utvecklingen av det interdisciplinära teamarbetet. Avhandlingen som helhet visar att hållbart förbättringsarbete inom arbetsterapi och team förutsätter a) ett reflekterande kollegialt förhållningssätt som ökar förmågan att hantera utmaningar i förbättringsarbetet, b) en i vardagsarbetet integrerad struktur förlångsiktigt förbättringsarbete med regelbunden avsatt tid och allokeradfaciliteringsfunktion, c) rutiner för att kontinuerligt hantera professionell kunskap från vetenskap och beprövad erfarenhet, d) ett strategiskt ledarskap och en gemensam kultur som håller drivkraften att förbättra levande över tid.Nyckelord: arbetsterapi, evidensbaserad praktik, hållbart förbättringsarbete,implementeringsteorier, MBT, OTIPM, PARiSH. hållbart förbättringsarbete, implementeringsteorier, MBT, OTIPM, PARiSH.
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| 59. |
- Sjöholm, Jennie
(författare)
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Heritagisation, re-heritagisation and de-heritagisation of built environments : The urban transformation of Kiruna, Sweden
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis presents research that aimed to contribute to the understanding of heritagisation in built environments and how heritagisation interacts with structural changes to an environment. The theoretical framework of the research was based on heritagisation, a concept defined by Harrison (2013) as the process through which objects, places and practices are turned into cultural heritage. The research was part of a single case study investigating conceptualisations of built heritage during the urban transformation of the town of Kiruna. Kiruna is a mining town in the northernmost part of Sweden that has plans to be relocated so that the mining company LKAB can continue mining the iron ore deposit that extends underneath the settlement. Kiruna is also a designated heritage site since the 1980s, and includes a large number of protected buildings. Hence, it is of interest how the built heritage is managed during the urban planning process. This is not only because the urban planning situation, which includes the relocation of an entire town, is special, but also because the town’s built heritage inevitably will change during the urban transformation. The research underlying this thesis has followed heritagisation during the urban transformation, from 2004, when the urban transformation was announced, until 2015. The empirical data used consist of planning documents, media reporting and observations, which together provide an overall view of the public discussions over the course of the urban planning process. Findings from the Kiruna case study show that the town’s officially recognised built heritage corresponds with the concept of an authorised heritage discourse (AHD). This heritage discourse was challenged by the urban transformation. Conservation goals are not clearly stated in the urban planning process and there are differing ideas for how to manage historic buildings during the urban transformation. These ideas shift both over time and between stakeholders, and the outcome of the urban planning process depends on a balance between the discourses of heritage conservation, urban development and architectural production. During the urban planning process some parts of the town’s official heritage have been reaffirmed as built heritage, while others have been dismissed. The concept of heritagisation was adopted and developed throughout the research presented in this thesis. This research also introduced the concepts of re-heritagisation and de-heritagisation, which refer to new heritagisation processes that occur when built heritage is contested and challenged during urban change. One of the main conclusions of the research was that the changes in meaning during the heritagisation process can be divided into four dimensions to analyse the complicated relationship between different interests and strategies in urban planning. Heritagisation can refer to: the addition of new heritage; reaffirmation of already designated heritage; re-interpretation of already designated heritage; rejection of previous designated heritage.
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| 60. |
- Szentes, Henrik
(författare)
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Organizational tensions when managing interorganizational projects : Applying a paradox perspective on large construction projects in Sweden
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Over the years, technological developments and societal changes have forced companies to modify their organizing practices. Companies operating in the construction sector are no exception, but due to their project-based structure, it is more difficult to coordinate change initiatives. Indeed, the construction sector is often described as conservative and unwilling to adopt change. However, there is a growing interest and ambition within the construction sector to develop and implement new ways of working. In addition, the need to adapt organizing practices of large construction projects due to societal changes is particularly strong because large construction projects are very dependent on a wide range of societal stakeholders.Changes in organizing practices as well as contextual changes often create new and intensify existing organizational tensions. Because most large construction projects span organizations, tensions can emerge and develop at several organizational interfaces. For instance, tensions related to control and flexibility can emerge between the client and the contractor, within each of these parties, but also between the project organization and societal stakeholders. Another type of tension relevant to construction projects is between the exploitation of current knowledge to perform efficiently today and the exploration of new knowledge in order to innovate for tomorrow’s demands. The abovementioned tensions have a paradoxical nature, meaning that although both elements in the tension make sense, they appear to be impossible to combine. Yet, applying a paradox perspective on organizational tensions recognizes that both elements are required when organizing. Moreover, prior research has shown that due to interdependencies between different organizing activities, responses to tensions may evolve into reinforcing cycles, substantially impacting performance. Therefore, the aim of this thesis is to create an improved understanding of the dependencies between tensions at different organizational interfaces in large construction projects by applying a paradox perspective. Empirical material was drawn from a qualitative study of seven large construction projects in Sweden, including three rounds of interviews during a four-year period, site visits, and reading of project documentation. All projects had an original contract sum of at least 50 million Euros and durations over several years; they included both transport infrastructure and building projects. An initial analysis of changes that project managers in large construction projects perceived in their role due to changing external and internal conditions provided a better understanding of the origin and nature of tensions in contemporary large construction projects, resulting in Paper I. Moreover, specific questions on the subject of exploration/exploitation during the first round of interviews provided input to Papers II and III. The two concluding rounds of interviews focused on dependencies between the tensions related to control/flexibility at different organizational interfaces and, analyzed using a paradox perspective, resulted in Papers IV and V. This thesis contributes to the construction management literature by showing that despite institutional barriers, substantial changes in the organizing practices of large construction projects have occurred over the years. However, the statements and attitudes exhibited by several interviewees indicate that the construction sector’s reputation for being conservative has become institutionalized, blocking creativity and favoring exploitation over exploration. This thesis also contributes to the literature on managing large construction projects by showing that distinguishing between interorganizational and intraorganizational aspects is essential to achieving a better understanding of the dependencies between organizing activities. For instance, analyses using a systemic paradox perspective showed that tensions related to control/flexibility coexist at both interorganizational and intraorganizational interfaces and that there are interdependencies between the two tensions, resulting in reinforcing cycles. For example, urges from client governance to their project manager to increase control of the contractor translated into an increase of control over the contractor project manager by his/her governance forum in order to retain the contractor’s flexibility. This triggered further controls by the client, and so on, in a vicious cycle of control. Similarly, this thesis demonstrates that in order to better understand how exploration and exploitation in large construction projects is dependent on intraorganizational strategies and decisions, it is fruitful to apply a systemic paradox perspective and simultaneously analyze both intraorganizational and interorganizational aspects.In addition, this thesis contributes to the literature on paradoxical tensions by identifying tensions and reinforcing cycles simultaneously nested across both inter- and intraorganizational interfaces, thus further calling for a systemic view of paradoxical tensions.For practitioners it is therefore essential to reflect not only which project managers to appoint in large construction projects, but also simultaneously thoughtfully chose members of each governance forum to avoid vicious cycles to occur.
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