<p>Examensarbetet har gjorts åt Höglunds flak i Säffle och behandlar en ny framstam till timmerlastbilar.</p><p>En framstam är ett lastskydd som förhindrar stockarna på en timmerlastbil från att tränga in i hytten vid en kollision. Framstammen används även vid lastning som ett mothåll att slå stockarna emot.</p><p>Kraven på framstammen från företaget är</p><p>• Lättare konstruktion</p><p>• Samma utböjning vid slagprov, ytbelastning och böjbelastningsprovning som nuvarande modell</p><p>• Billigare eller samma pris som föregående modell</p><p>• Klara proven enligt SS 2563, SS 2564</p><p>• Vara estetiskt tilltalande för kund</p><p>• Anpassningsbar höjd</p><p>• Om möjligt få så mycket tillverkning som möjligt till den egna verkstaden</p><p>Arbetet delades in i två delar där en del är att konstruera plåten och hur denna skall styvas till. Den andra är att konstruera staken som håller upp plåten och tar den största delen av slagkraften.</p><p>På framstamsplåten togs det fram 2 koncept.</p><p>Bockningskonceptet.</p><p>Konceptet består av en aluminiumplåt 6082-T6 som bockats till en L-profil runt kanterna för att styva upp plåten</p><p>Fyrkantsprofil.</p><p>Detta koncept består av en fyrkantsprofil i aluminium som nitas fast mot plåten.</p><p>På staken togs det fram tre koncept. Alla tre är beräknade med att vara i samma material ett höghållfast stål vid namn Domex 650 med en sträckgräns på ca 650Mpa.[5]</p><p>JL-profilen</p><p>Är en profil som är lätt att tillverka genom bockning och är lätt att fästa in i både plåten och i rambalken.</p><p>I-profilen</p><p>I-balken är gjord med en större fläns mot plåten för att underlätta vid infästning och en mindre fläns på andra sidan för att minska vikten. På grund av att detta inte är en original balk så kommer denna modell att strängpressas.</p><p>W-profilen</p><p>W- profil som även denna skulle stängpressas och är även lätt att fästa mot plåten. Den har tagits fram med tanken på en T-balk som sedan stadgats upp med två stycken förstyvningar.</p><p>Fyrkantröret har en lägre vikt på 19 kg i jämförelse med rör- profilen, detta motsvarar en viktbesparing på 55%.</p><p>I-profilen klarar att ta upp 0,6kJ mer än Z-profilen samtidigt som den är 23 kg och 23%</p><p>lättare.</p> / <p>The work is done for the company Höglunds flak in Säffle and aims to develop a new front wall to a timber truck.</p><p>A front wall is what protects the cabin from the logs in case of a collision. The front wall is also used while loading the truck as a loading fixture to beat the logs against.</p><p>The requirements for the front wall from the company are:</p><p>• Easier construction</p><p>• The same deformation at impact testing, surface testing and bending load as the original.</p><p>• Cheaper or the same price as the previous model</p><p>• Withstand the standardization SS 2563, SS 2564</p><p>• Be attractive to the customer</p><p>• Customizable height</p><p>• If possible, get as much production as possible to the own workshop</p><p>The work was divided into two parts where one is to make the plate and how to make it rigid. The second is the beams which are going to keep up the plate and takes the greater part of the impact force.</p><p>Two concepts on the front wall plate, both is of the same material 6082-T6.</p><p>Bending concept.</p><p>The concept consists of an aluminium plate which is bended to an L-profile around the edges to rigid up the plate.</p><p>Square concept.</p><p>This concept consists of a square tube in aluminium which is riveted firmly against the plate.</p><p>Three concepts on the beams. All three are estimated to be in the same material Domex 650</p><p>JL-profile</p><p>Is a profile that is easy to manufacture by bending and is easy to mount on both the plate and in the frame beams.</p><p>I-profile</p><p>The I-beam is made with a larger flange to the plate in order to facilitate the attachment and a small flange on the other side to reduce weight. However, because this is not an original beam it will be manufactured through extrusion.</p><p>W-profile</p><p>W-profile is going to be extruded and is also easy to attach to the plate. It has been developed with the idea of a T-beam which then is stated up with two webs.</p><p>Of the two plate concepts it was the Square concept which was best suited one. The bending concept was not chosen because the material of the plate was for brittle and couldn’t be bent as much as wanted.</p><p>The analysis of the plate was made according to the standard SS2563, SS 2564 with a pressure of a certain distance from the base.</p><p>The FEM analysis at the plate shows that there is no residual deformation, which is the same as the original plate. The square pipe has a lower weight with 19 kg which is 55% lighter compared with the circular pipe profile.</p><p>The profile is able to take up 0,6 kJ more than the Z-profile and 23kg and 23% lighter</p>

Slurry transport is a key material handling technology in a number of industries. In oilsands ore transport, slurry pipelining also promotes conditioning to release and aerate bitumen prior to separation. Reliability of slurry transport pipelines is a major ongoing problem for operating companies due to unexpected piping failures, even when conservative maintenance strategies are employed. To date, no accurate model has been developed to predict wear rates in slurry transport pipelines, although previous studies have shown that important variables include flow rate, slurry density, and particle size distribution. This work investigates erosion wear mechanisms causing inner pipe wall wear due to sand slurry flow in a horizontal section of pipe under steady state conditions. A corresponding lumped-parameter erosion wear model is presented based on simplification of the physics of oilsands slurry flow. An apparatus was designed and developed to measure the forces acting on the pipe inner wall to monitor forces related to erosion in a laboratory-scale sand slurry loop, and preliminary results are presented with recommendations for future work. / Engineering Management

Collecting microlymphatics play a vital role in promoting lymph flow from the initial lymphatics in the interstitial spaces to the large transport lymph ducts. In most tissues, the primary mechanism for producing this flow is the spontaneous contractions of the lymphatic wall. Individual units, known as lymphangion, are separated by valves that help prevent backflow when the vessel contracts, thus promoting flow through the lymphatic network. Lymphatic contractile activity is inhibited by flow in isolated lymphatics, however there are virtually no in situ measurements of lymph flow in these vessels. Initially, a high speed imaging system was set up to image in situ preparations at 500 fps. These images were then manually processed to extract information regarding lymphocyte velocity (-4 to 10 mm/sec), vessel diameter (25 to 165 um), and particle location. Fluid modeling was performed to obtain reasonable estimates of wall shear stress (-8 to 17 dynes/cm2). One of the difficulties encountered was the time consuming methods of manual particle tracking. Using previously captured images, an image correlation method was developed to automate lymphatic flow measurements and to track wall movements as the vessel contracts. Using this method the standard error of prediction for velocity measurements was 0.4 mm/sec and for diameter measurements it was 7.0 µm. It was found that the actual physical quantity being measured through this approach is somewhere between the spatially averaged velocity and the maximum velocity of a Poiseuille flow model.

Carbon nanotubes (CNT) are a new form of carbon with exceptional electrical and mechanical properties. This makes them attractive as inclusions in nanocomposite materials with the potential to provide improvements in electrical and mechanical properties and allows for the creation of a new range of multifunctional materials. In this study single wall carbon nanotubes (SWCNT) were dispersed in polystyrene using a solution mixing method, with the aid of a surfactant. A good dispersion was achieved and the resulting nanocomposites were characterized for electrical conductivity and mechanical properties by 3 point flexural and fracture toughness tests. Results show a significant improvement in electrical properties with electrical percolation occurring between 0.1 and 0.2 wt%. A minor improvement was observed in the flexural modulus but the strength and fracture toughness values in the nanocomposites decreased relative to the neat material. Scanning electron microscopy (SEM) was performed to characterize the morphology and fracture surface of the specimens. The results of testing and microscopy show that the presence of the nanotubes has an adverse effect on the crazing mechanism in Polystyrene (PS) resulting in a deterioration of the mechanical properties that depend on this mechanism.

Background: The EXO (EXORDIUM) gene was identified as a potential mediator of brassinosteroid (BR)-promoted growth. It is part of a gene family with eight members in Arabidopsis. EXO gene expression is under control of BR, and EXO overexpression promotes shoot and root growth. In this study, the consequences of loss of EXO function are described. Results: The exo loss of function mutant showed diminished leaf and root growth and reduced biomass production. Light and scanning electron microscopy analyses revealed that impaired leaf growth is due to reduced cell expansion. Epidermis, palisade, and spongy parenchyma cells were smaller in comparison to the wild-type. The exo mutant showed reduced brassinolide-induced cotyledon and hypocotyl growth. In contrast, exo roots were significantly more sensitive to the inhibitory effect of synthetic brassinolide. Apart from reduced growth, exo did not show severe morphological abnormalities. Gene expression analyses of leaf material identified genes that showed robust EXO-dependent expression. Growth-related genes such as WAK1, EXP5, and KCS1, and genes involved in primary and secondary metabolism showed weaker expression in exo than in wild-type plants. However, the vast majority of BR-regulated genes were normally expressed in exo. HA- and GFP-tagged EXO proteins were targeted to the apoplast. Conclusion: The EXO gene is essential for cell expansion in leaves. Gene expression patterns and growth assays suggest that EXO mediates BR-induced leaf growth. However, EXO does not control BR-levels or BR-sensitivity in the shoot. EXO presumably is involved in a signalling process which coordinates BR-responses with environmental or developmental signals. The hypersensitivity of exo roots to BR suggests that EXO plays a diverse role in the control of BR responses in the root.

No description available.

No description available.

UDP-galactopyranose mutase (UGM) is a flavoenzyme which catalyzes the interconversion of UDP-galactopyranose (UDP-Galp) and UDP-galactofuranose (UDPGalf). UDP-Galf is the active precursor of Galf residues. Glycoconjugates of Galf residues are found in the cell wall of bacteria and on the cell surface of higher eukaryotes. Galf residues have not been found in humans and the fact that they are essential for the growth of pathogenic bacteria makes UGM a potential antibacterial target. In the present study, crystal structures of UGM from Deinocococcus radiodurans (drUGM) in complex with substrate (UDP-Galp) were determined. UDP-Galp is buried in the active site and bound in a U-shaped conformation. The binding mode and active site interactions of UDP-Galp are consistent with the previous biochemical and mechanistic studies. The mobile loops in the substrate complex structures exist in a closed conformation and Arg198 on one of the mobile loops stabilizes the phosphate groups of the substrate. The anomeric carbon of galactose is 2.8 Å from the N5 of FAD (in the reduced complex) favorable to form FAD-galactosyl adduct. In addition to substrate complex structures, the crystal structures of drUGM in complex with UDP, UMP, and UDP-Glc have been determined. The mobile loops in all these complexes exist in a closed conformation. Inhibitors for UGM were identified by ligand-based and structure-based methods. The phosphonate analog of UDP-Galp (GCP) showed only weak inhibition against various bacterial UGMs. The structure of drUGM in complex with GCP provided a basis for its inhibitory activity. Poor stabilization of the phosphate groups by conserved arginines (Arg198 and Arg305) and altered sugar binding mode account for its activity. Novel indole-based (LQ1, LQ6 and LQ10) inhibitors of UGM were identified through structure-based virtual screening (SBVS) of a chemical library. Inhibition studies also allowed the identification of an active site aspartic acid that plays role in inhibitor binding. The structural studies on drUGM provided a basis for understanding substrate binding to UGM. In vitro enzyme inhibition studies allowed the identification of novel indole-based inhibitors. The structural and inhibition studies reported here enhance the understanding of UGM-ligand interactions and will assist in the development of more potent inhibitors of UGM.

An experimental program was performed for qualitative and quantitative comparison of the maximum tensile resistance of contact and non-contact lap spliced bars in reinforced concrete block masonry using double pullout and wall splice specimens. A total of 32 specimens were tested, consisting of an equal number of double pullout specimens and full-scale wall splice specimens. Both specimen types had the identical cross-section. Eight replicate specimens for each specimen type were constructed with both contact and non-contact lap splice arrangements. Grade 400 deformed reinforcing bars with a 300 mm lap splice length were provided in all specimens. The double pullout specimens were tested applying direct tension to the lapped reinforcing bars. The splice resistance and displacement were recorded during testing. All double pullout specimens with contact lap splices developed, as a minimum, the yield strength of the reinforcing bars and generally displayed evidence of a yield plateau. In contrast, the double pullout specimens with non-contact lap splices failed when only 46.1% of the theoretical yield strength of the reinforcing bars was recorded as the maximum splice resistance. The difference between the average value of the tensile resistance in the contact and non-contact spliced bars was identified as being statistically significant at the 95% confidence level. Wall splice specimens were tested under a four-point loading arrangement with the lapped bars located in the constant moment region. The applied load and specimen deflection were recorded until failure occurred. A numerical analysis was then performed to calculate the maximum resistance of the spliced bars. The specimens with contact lap splices developed the theoretical yield capacity of the reinforcing bars. In contrast, the wall splice specimens with non-contact lap splices developed an average tensile resistance of 78% of the theoretical yield capacity. The difference between the average tensile resistances of the lapped bars in the two splice arrangements was identified as being statistically significant at the 95% confidence level. On average, the contact and non-contact lap spliced bars in the double pullout specimens developed 8.47% and 41.2% less tensile resistance, respectively, as compared to the wall splice specimens with the identical splice arrangement. Both differences were identified as being statistically significant at the 95% confidence level. Bond loss between the reinforcing bars and the surrounding grout was identified as the failure mode for both the double pullout and wall splice specimens with contact lap splices. In contrast, bond loss at the masonry block/grout interface was observed along the non-contact lapped bars in both specimen types, as identified by visual observations upon removal of the face shell and the surrounding grout. Based on the test results of the wall splice specimens with non-contact lap splices, a correction factor of 1.5 is suggested when calculating the effective splice length for the non-contact splice arrangement as tested.

Inverse spectral techniques are developed in this dissertation for recovering the shear modulus and residual stress of soft tissues. Shear modulus is one of several quantities for measuring the stiffness of a material, and hence estimating it accurately is an important factor in tissue characterization. Residual stress is a stress that can exist in a body in the absence of externally applied loads, and beneficial for biological growth and remodeling. It is a challenge to recover the two quantities in soft tissues both theoretically and experimentally. The current inverse spectral techniques recover the two unknowns invasively, and are theoretically based on a novel use of the intravascular ultrasound technology (IVUS) by obtaining several natural frequencies of the vessel wall material. As the IVUS is interrogating inside the artery, it produces small amplitude, high frequency time harmonic vibrations superimposed on the quasistatic deformation of the blood pressure pre-stressed and residually stressed artery. The arterial wall is idealized as a nonlinear isotropic cylindrical hyperelastic body for computational convenience. A boundary value problem is formulated for the response of the arterial wall within a specific class of quasistatic deformations reflexive of the response due to imposed blood pressures. Subsequently, a boundary value problem is developed from intravascular ultrasound interrogation generating small amplitude, high frequency time harmonic vibrations superimposed on the quasistatic finite deformations via an asymptotic construction of the solutions. This leads to a system of second order ordinary Sturm-Liouville problems (SLP) with the natural eigenfrequencies from IVUS implementation as eigenvalues of the SLP. They are then employed to reconstruct the shear modulus and residual stress in a nonlinear approach by inverse spectral techniques. The shear modulus is recovered by a multidimensional secant method (MSM). The MSM avoids computing the Jacobian matrix of the equations and is shown to be convenient for manipulation. Residual stress is recovered via an optimization approach (OA) instead of the traditional equation-solving method. The OA increases the robustness of the algorithms by overdetermination of the problem, and comprehensive tests are performed to guarantee the accuracy of the solution. Numerical examples are displayed to show the viability of these techniques.