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Two computed tomography scanners have been used to acquire density profiles from five wooden test pieces. These test pieces had annual growth ring widths varying between about 0.6 mm and 3.5 mm. The two scanners employed were a medical scanner, a GE 9800 Quick scan system, and a purpose built microscanner constructed around a Rigaku D-Max II diffractometer. The results demonstrated that the annual growth rings could be resolved and density measurements could be reliably determined using the microscanner when the annual growth rings were about 0.9 mm or greater in width. The medical scanner could not satisfactorily measure density in carlywood or latewood resions even in samples where the annual growth ring width was of the order of 3.5 mm. A small difference in density measurements could be observed between the two scanners for the same specimens. The difference is attributed to calibration differences, the reconstruction algorithms used and the different geometries of the two systems; particularly in relation to the detector apertures. The larger detector size in the medical system results in too high or too low density values in the carlywood or the latewood respectively due to spatial averaging. However, the medical scanner provides satisfactory density accuracy in specimens where the density is very uniform or as long as measured areas include both carlywood and latewood. An accuracy of ±2-6 kg/m3 at 95% confidence level can then be expected.
N/A / Link / Lindgren , Owe / 1991

Luleå tekniska universitet Övrigt
Denna rapport beskriver de studier som en grupp av forskare vid Institutionen för Samhällsbyggnad, Luleå tekniska universitet, genomfört beträffande vissa centrala delar av projektupplägget vid byggandet av kulsinteranläggning MK3 vid LKAB:s anläggningar i Vitåfors under perioden Nov. 2004 till Dec. 2006. Vid tidpunkten för investeringsbeslutet för kulsinterverket MK3, som är det första i en rad av planerade stora investeringar, var LKAB i en situation där man hade dragit ner egna projekterings- och projektledningsresurser efter att ha genomfört stora investeringar under 1990-talet. I det läget var det en strategiskt viktig beslutsfråga för företagsledning och styrelse hur MK3 projektet skulle styras och organiseras för att säkerställa projektets höga målsättningar beträffande tid, funktion och ekonomi. Dessutom är projekt av typen MK3 ofta dynamiska till sin natur (kort ledtid, snabba informations- och kommunikationsbehov), tekniskt och administrativt komplexa och med många risker och osäkerhetsfaktorer som måste hanteras kontinuerligt under projekttiden. LKAB har för projekt MK3 valt att söka samverkanslösningar för att med be- gränsade egna resurser kunna följa upp och påverka projektets funktionsut- formning, tid för genomförande samt projektets investeringskostnader. Sålunda har byggdelen av MK 3 upphandlats med transparent ersättningsform och strukturerad samverkansform, typ partnering. Genomförandeformen är totalentreprenad (ABT 94) där byggentreprenören administrativt ansvarar för detaljprojekteringen. Till huvudentreprenör på byggdelen och med samordningsansvar även för installationsfasen av separat upphandlade processdelar har valts NCC. Enligt de resultat från genomförda studier som redovisas i denna rapport anser en stor majoritet av i projekt MK3 medverkande beställar-, entreprenörs- och konsultrepresentanter att valet av upphandlingsmodell med klar samverkansprofil för projektet varit lyckad. En majoritet anser också att detta varit av avgörande betydelse för att kunna nå projektets målsättningar beträffande funktion, tid och ekonomi. Bland de fördelar som upphandlingsmodellen medfört är att samarbetsklimatet mellan aktörerna upplevts som bättre än vid konventionellt upphandlade projekt. Detta har ett egenvärde i sig men är framförallt en nödvändig förutsättning för att kunna nyttja strategiska viktiga kompetenser och kunskaper på ett effektivt sätt för att projektets målsättningar skall säkerställas. Effekterna av det goda samarbetsklimatet är speciellt tydliga i det sätt projekteringen av anläggningen kunnat bedrivas i effektiv samverkan mellan kund, entreprenör och konsulter (Concurrent engineering). Vid projektgenomförandet har även De IT-stödsystem, speciellt 3D modellering och VR använts på innovativt sätt som kommunikations- och informationsverktyg. Användandet av detta i projekteringen har på många sätt bidragit till att skapa mervärde för kunden och minska byggfelen i produktionen. Enbart besparingarna i en effektivare projektsamordning torde ha bekostat investeringen i 3D och VR med råge.
N/A / Link / Olofsson , Thomas / 2007

Luleå tekniska universitet Övrigt
1905209509 / Link / Jonasson , Jan-Erik / 2006

Luleå tekniska universitet Övrigt
N/A / Link / Grundberg , Stig / 2001

Luleå tekniska universitet Övrigt
N/A / Link / Ruth , Walter / 1999

Luleå tekniska universitet Övrigt
In this paper, a simple model concept is presented to describe the dynamics of road runoff and suspended-solid transport from a small urban catchment in northern Sweden. The study period stretches from March 28 to May 28, 2000, including both snowmelt and rainfall. A modified degree-day method is used to describe the snowmelt and the transport of suspended solids is described by a linear build-up function and a wash-off model. The model was verified through measurements taken from March 22 to May 22, 2001. The results from the simulations showed that the simple model concept was capable of describing the dynamics of road runoff and suspended solids rather well, based on the continuous course of events for the whole modelling period. However, if the model was used for simulating a snowmelt period, or single events during snowmelt, the model approach would be too simple.
1-8433-9574-6 / Link / Westerlund , Camilla / 2005

N/A / Link / Marklund , Erik / 2005

 The loss of chlorine during the irradiation of PVC and PVDC in the electron microscope has been measured by the decay of the X-ray chlorine Kα signal. A number of factors affecting the measured beam damage curves have been considered and the experimental errors reduced to ±10%. The results show that the chlorine decay curves can be best described by the sum of two exponentials, corresponding to the two different chlorine decay processes, these being: the dehydrochlorination of the polymer molecules and the dehydrochlorination of the polyene structure formed by the beam damage. The higher initial chlorine content of PVDC compared to PVC will result in a larger amount of chlorine atoms reacting with the polyene structure, which is more stable in the electron beam than the undamaged polymer. The chlorine loss, measured by X-ray analysis, has been compared to the mass loss, measured by energy loss analysis, and also with the volume changes of isolated spherical PVC particles. It has been concluded that the mass loss is almost entirely due to chlorine loss and that the residual structure has a density similar to the undamaged PVC.
N/A / Link / Lindberg , Henrik / 1985

Light-induced aging of lignocellulosic materials was studied. A new technique involving selectively α-,β- and γ-13C-enriched cell wall-dehydrogenation polymers (CW-DHP) and solid state 13C nuclear magnetic resonance (NMR) spectroscopy was used. CW-DHP showed a decrease in the amount of end-groups of both coniferaldehyde and coniferyl alcohol type. It was also found that the end-groups become saturated and that the therminal functionalities
N/A / Link / Parkås , Jim / 2002

9073592011 / Link / Vännman , Kerstin / 1990

The present work is a study of how various parameters affect the cutting forces at, and near a cutting edge when cutting wood at full speed and with all cutting edges of the tool. Statistical methods from experimental results are used to develop a model
N/A / Link / Axelsson , B.O.M. / 1993

A method is presented for studying the effect of momentary disturbances due to variations in wood structure on the cutting force near the cutting edge. Force and density measurements are converted to a gray scale image. This method is very effective as regards the evaluation of experimental tests
N/A / Link / Axelsson , B.O.M. / 1991

N/A / Link / Antti , Lena / 2001

Luleå tekniska universitet Övrigt
Thermosyphons have been used to stabilise ground in permafrost areas since the 60's. On-grade foundations over ice rich permafrost require insulation below the floor to retard heat flow and a cooling system below the insulation to prevent thermal degradation of the underlying permafrost. Heat transfer in the ground and at thermosyphon installations are explained and discussed in this report. Further, methods for designing thermosyphon installations at buildings and roadways are described. Illustrated, as examples, are the case with a varying surface temperature, a roadway and a cross-country ski track.
N/A / Link / Forsström , Anna / 2002

Luleå tekniska universitet Övrigt
Telecom operators face an increasing need for service quality management to cope with competition and complex service portfolios in the mobile sector. Improvements in this area can lead to significant market benefits for operators in highly competitive markets. We propose an architecture for a service monitoring tool, including a time aware formal language for model specification. Using these models allows for increased predictability and flexibility in a constantly changing environment.
0-7695-2847-3 / Link / Wallin , Stefan / 2007

Luleå tekniska universitet Övrigt
This Licentiate thesis is focussed on some new questions in homogenization theory, which have been motivated by some concrete problems in tribology. From the mathematical point of view, these questions are equipped with scales of Reynolds equations with rapidly oscillating coefficients. In particular, in this Licentiate thesis we derive the corresponding homogenized (averaged) equation. We consider the Reynolds equations in both the stationary and unstationary forms to analyze the effect of surface roughness on the hydrodynamic performance of bearings when a lubricant is flowing through it. In Chapter 1 we describe the possible types of surfaces a bearing can take. Out of these, we select two types and derive the appropriate Reynolds equations needed for their analysis. Chapter 2 is devoted to the derivation of the homogenized equations, associated with the stationary forms of the compressible and incompressible Reynolds equations. We derive these homogenized equations by using the multiple scales expansion technique. In Chapter 3 the homogenized equations for the unstationary forms of the Reynolds equations are considered and some numerical results based on the homogenized equations are presented. In chapter 4 we consider the equivalent minimization problem for the unstationary Reynolds equation and use it to derive a homogenized minimization problem. Finally, we obtain both the lower and upper bounds for the derived homogenized problem.
N/A / Link / Essel , Emmanuel Kwame / 2007

Luleå tekniska universitet Övrigt
The MAX phases constitute a group of ternary ceramics which has received intense attention over the last decade due to their unique combination of properties. The Ti3SiC2 is the most well studied MAX phase to date and it has turned out to be a promising candidate for high temperature applications. It is oxidation resistant, refractory and not susceptible to thermal shock, while at the same time it can be machined with conventional tools which is of great technological importance. Most attempts to synthesize bulk Ti3SiC2 have involved pure titanium in the starting powder mixtures, but Ti powder is oxidising and requires an inert atmosphere throughout the synthesis process which makes the procedures unsuitable for large scale production. The aim of the first part of this study was to delineate the influence of sintering time and temperature on the formation of Ti3SiC2 from a starting powder which does not contain pure titanium. Titanium silicon carbide MAX phase was synthesised from ball milled TiC/Si powders, sintered under vacuum for different times and temperatures. After heat treatment the samples were evaluated using scanning electron microscopy (SEM) and x-ray diffraction (XRD). This study showed that TiC was always present in the final products whereas TiSi2 was an intermediate phase to the Ti3SiC2 formation. The highest amount of Ti3SiC2 was achieved for short holding times of 2-4 hours, at high temperatures, 1350-1400¢ªC. More elevated temperatures or extended times resulted in silicon loss and decomposition of Ti3SiC2. In the second part of this study the sintering reactions and the mechanisms of formation of Ti3SiC2 were investigated by x-ray diffractometry, thermodilatometry, thermogravimetry, differential scanning calorimetry and mass spectrometry. TiC/Si powders of the different ratios; 3:2 and 3:2.2, were heated to different temperatures under flowing argon gas in a dilatometer and examined by XRD. The TiC/Si powder samples of the ratio 3:2 were further investigated by the other thermal analysismethods. The results confirmed the presence of the intermediate phase TiSi2. From 1500¢ªC silicon evaporation and MAX phase decomposition were observed, and the results show that the MAX phase formation may be concurrent with the melting of silicon. TiC was always present in the final products, either as a reactant or as a decomposition product. The extra silicon of the 3:2.2 TiC/Si powder significantly increased the Ti3SiC2 conversion and no intermediate phases were observed for this powder mixture. The Si of these samples did not melt or evaporate, and only minor decomposition was observed even at 1700¢ªC. These results indicate that the silicon content of the initial powder mixture is decisive to the reaction mechanisms of the sintering process.
N/A / Link / Kero , Ida / 2007

We give sharp estimates for the fractional maximal function in terms of Hausdorff capacity. At the same time we identify the real interpolation spaces between L 1 and the Morrey space L 1,λ  . The result can be viewed as an analogue of the Hardy-Littlewood maximal theorem for the fractional maximal function.
N/A / Link / Kruglyak , Natan / 2006

Chloroform was readily converted to formic acid through the nucleophilic attack of hydroxyl anion under the certain reaction conditions (pH>12, temp.>°C). When guaiacol was reacted with hypochlorite at such reaction conditions, the generation of chloroform was almost completely reduced. Successful reduction of the chloroform generation was also observed in alkaline hypochlorite bleaching of kraft pulps and DIP without any loss in pulp quality. Even when the hypochlorite bleaching was carried out under the open system (no sealing of the reaction vessel), nearly 90% of the generated chloroform was converted to formic acid.
N/A / Link / Magara , Kengo / 2003

Luleå tekniska universitet Övrigt
91-44-01690-5 / Link / Vännman , Kerstin / 2002

Luleå tekniska universitet Övrigt
Syftet med studien var att med utgångspunkt i SFU-projektet studera villkor och förutsättningar, för ökad delaktighet och självbestämmande, för utvecklings-störda som bor i gruppbostad. Studien genomfördes i en glesbygdskommun i norra Sverige och data genererades genom fältobservationer på en gruppbostad för utvecklingsstörda och intervjuer med åtta personal och tre gode män, före och efter projektets genomförande. Avsikten med fältobservationerna var att få insyn i de vardagliga mötena och den sociala interaktionen i den givna kontexten, samt en möjlighet att få kunskap om brukarnas möjligheter till delaktighet och självbestämmande. Intervjuerna genomfördes för att få ytterligare och fördjupade svar på forskningsfrågorna som var: Vilka innebörder har begreppen delaktighet och självbestämmande för personal och brukarnas företrädare, gode män? Hur går kommunen till väga för att realisera dessa mål och hur lyckas de? Finns det några motkrafter för att arbeta mot att dessa mål, och i så fall, vilka är de viktigaste? Det övervägande intrycket av intervjuerna var att det fanns en stor osäkerhet hos personalen om innebörden i begreppen delaktighet och självbestämmande, och betydelsen av att brukarna skulle ha dessa möjligheter. Exempel på konkreta förändringar som intervjupersonerna ansåg hade skett efter projektet avslutats var att de hade startat ett "boenderåd" och att klimatet på gruppbostaden hade blivit mera tillåtande. En paradox var dock att intervjupersonerna ansåg att det var viktigt att brukarna får vara med och bestämma samtidigt som det var personalen som i stor utsträckning bestämde. Dessutom ansåg de att personalen har börjat respektera brukarna mera. Ett annat motsägelsefullt uttalande var att personalen var rädda för att brukarna skall börja "styra" för mycket om de fick bestämma i vissa frågor, samtidigt som de menade att brukarna inte var med och bestämde därför att de har så dåligt självförtroende. De mest betydande hindren för brukarnas möjligheter till självbestämmande var av organisatorisk, social och kommunikativ karaktär. De organisatoriska hindren var exempelvis oklara roller, brist på ledning och handledning samt behovet av planering och struktur av arbetet. Det visade sig också att det fanns en stark kollektiv praxis, som bland annat innebar att arbetet var rutinstyrt, och de rutiner som hade skapats var svåra att förändra eftersom de upplevdes som en trygghet. Det kan vara en av anledningarna till att utbildningen, som var den största interventionen i projetet inte fick den avsedda effekten.
N/A / Link / Widerlund , Lena / 2007

In order to characterize very local energy dissipation during crack propagation in polymers, an ultramicrotome was instrumented to measure the energy dissipated during sectioning. The work to section per unit area, W s, was measured for five different amorphous polymers [polymethyl methacrylate (PMMA), polystyerene (PS), polycarbonate (PC) and two epoxy resins] in the glassy state. When the section thickness was varied between 60 and 250 nm, W s varied between 15 and 100 Jm-2, depending on the material and section thickness. The method and the results are compared with other methods used for determining the energy dissipation at a local level as well as at a macroscopic level in polymers. The differences between different polymers were found to be contradictory to macroscopic fracture toughness, G lc, measurements. The material that showed the highest W s had the lowest G lc values reported. Possible mechanisms for energy dissipation during sectioning are also discussed.
N/A / Link / Ericson , M.L. / 1996

Luleå tekniska universitet Övrigt
Ultramicrotomes are generally used for preparation of very thin sections for transmission electron microscopy. Recently it has been shown that when the sample holder of the ultramicrotome is instrumented with a force transducer, it is possible to measure the very small sectioning force during sectioning, and calculate the energy dissipated. In the present work, the instrumentation is further improved. The new sample holder, which uses two piezo-electric force transducers can measure two force components simultaneously. It is not only robust and stiff, but it also shows high sensitivity and reproducibility. It is possible to detect sectioning forces lower than 0.1 mN. The method is demonstrated on two amorphous polymers, poly(methyl methacrylate) and epoxy. Fracture energies in the same order of magnitude as theoretical predictions from chemical bond fracture only are recorded. It is therefore suggested that the method of instrumented ultramicrotomy is a useful tool when information on covalent bond density isneeded. Potential future applications are identified including research on nano-scale fracture, characterization of molecular anisotropy and developments of the ultramicrotome
N/A / Link / Ericson , Mats L. / 1997

The electron beam damage of PVC, PVDC, chlorinated PE, chlorosulphonated PE (Hypalon) and chloroendic acid polyester has been studied by chlorine loss and mass loss measurements. The mass loss decay curves have been recalculated for true mass loss and correlated with the X-ray measurements of chlorine loss. It is shown that the major mechanism of degradation in these polymers is dehydrochlorination. The rate of dehydrochlorination is dependent on the chemical structure of the polymer, and in particular on the availability of hydrogen for HCl formation. However, in case of chloroendic acid polyester, more complicated volatile chlorinated compounds are also formed. The dehydrochlorination rate and mass loss of miscible PVC blends, namely PVC with organotin stabilizer, PMMA, PCL and SAN have been studied. The rate of chlorine loss from PVC was found to be unchanged for all blends except for PMMA and PCL, where it slightly increased due to the chemical reaction between the molecular fragments of both polymers. The differences between the thermal degradation and electron beam damage are also discussed.
N/A / Link / Lindberg , Henrik / 1989

Luleå tekniska universitet Övrigt
3-8613-0812-6 / Link / Clarin , Mattias / 2005

N/A / Link / Collin , Peter / 2005

Luleå tekniska universitet Övrigt
0-08-043334-0 / Link / Abrahamsson , Lena / 1998

Luleå tekniska universitet Övrigt
N/A / Link / Jonsson , Bo / 2005

The advantages of fiber-reinforced polymer (FRP)-strengthening have been shown time and again during the last decade. Several thousand structures retrofitted with FRPs exist worldwide. There are various reasons why the retrofit is needed, but it is not uncommon for the demands on the structure to change with time, as buildings and civil structures usually have a very long life. The structures may have to eventually carry larger loads or fulfill new standards. In extreme cases, a structure may need repair due to an accident or to errors made during the design or construction phases, and must therefore be strengthened before it can be used. Different methods to retrofit with FRPs also exist, such as bonding of plates or sheets, with their use of epoxy as the bonding agent being the commonality. Epoxy provides very good bond to concrete and is durable and resistant to most environments in the building industry. However, epoxy may also create problems in the working environment, needs a minimum application temperature, and creates diffusion-closed surfaces. These drawbacks can be overcome if the epoxy can be replaced with a cementitious bonding agent. In this paper tests are presented where the epoxy has been replaced with a cement based bonding agent for retrofitting. Pilot tests show that very good composite action can be achieved and that only minor changes in the design procedure need to be taken.
N/A / Link / Täljsten , Björn / 2007