Sammanfattning Syftet med denna studie var att söka samband mellan upplevd stress och självtillit hos kvinnor i arbetsrelaterade situationer. Frågeställning: Finns det ett samband mellan upplevd stress och självtillit hos kvinnor i arbetsrelaterade situationer? Vår hypotes var att det finns ett samband mellan en kvinnas upplevda stress och självtillit i arbetsrelaterade situationer. För vår undersökning krävdes att vi kan mäta två variabler; stressnivå och självtillit hos en individ. Vi har genomfört en kvantitativ studie där vi har använt oss av en webbaserad enkät. Vi har valt att studera yrkesverksamma kvinnor och har tillfrågat 100 kvinnor som alla har någon form av relation till oss. 62 % av kvinnorna svarade på enkäten vilket gav oss ett externt bortfall på 38 %. Det interna bortfallet eliminerade vi genom att utforma enkäten så att deltagarna antingen svarade på alla frågor eller ej registrerades. Våra resultat valde vi att sammanställa i Excel och statistikprogrammet SPSS. Vi fick fram en korrelationskoefficient på -0,326 med en signifikansnivå på 0,010. Detta visar att korrelationen var svag men signifikant och att det fanns ett statistiskt säkerställt negativt samband mellan upplevd stress och självtillit. 60 % av kvinnorna som deltog i studien upplevde sitt arbete stressande ofta eller alltid och 90 % av studiedeltagarna upplevde att de ibland hade för mycket att göra på sitt arbete. 52 % av kvinnorna kände att de ofta eller alltid fick det stöd de behövde för att klara sina arbetsuppgifter. 50 % uppgav att de alltid eller ofta hade tillräckligt med tid att koppla av medan 29 % kände att de ibland hade tillräckligt med tid att koppla av. Vi kan konstatera att det finns ett troligt samband mellan upplevd stress och självtillit hos kvinnor i arbetsrelaterade situationer då både tidigare forskning och vår undersökning tyder på detta förhållande. I vår studie hade studiedeltagarna generellt en hög självtillit och en relativt låg upplevd stressnivå. Den stress som deltagarna upplevde verkar kompenseras genom upplevelsen av kontroll över sitt arbete och möjligheten till återhämtning. Vi kan således konstatera att det kan vara positivt för en arbetsgivare att främja balans mellan medarbetarnas krav och kontroll. I framtiden kan det vara av intresse att studera orsakssambandet mellan de undersökta faktorerna då det i vår studie inte var möjligt. / Abstract The aim of this study was to find out whether there is a correlation between experienced strain and self-efficacy for women in work related situations. Question at issue: Is there a correlation between experienced strain and self-efficacy for women in workrelated situations? To make the wanted comparison we had to be able to measure two variables; ones experienced strain level and the extent of self-efficacy. We have carried out a quantitative study by using a questionnaire. The population for the study consisted of 100 women in work related situations. 62 % decided to participate which gave us an external loss of 38 %. We were able to eliminate the internal loss by designing the questionnaire so that the participants either answered all the questions or where not registered. We have compiled the result of the study in Excel and in the statistics program SPSS. That gave us the correlation coefficient -0,326 at a signification level of 0,010. This shows that the correlation was weak but significant and that the relation between strain and self-efficacy was negative. 60 % of the women in the study found their work to be stressful often or always and 90 % of the participants in the study found that they sometimes had too much to do at work. 52 % of the women found that they often or always received the support they needed to manage their work. 50 % stated that they always or often had time to relax whereas 29 % felt that they sometimes had time to relax. We can establish that there is a possible correlation between strain and self-efficacy for women in work related situations. Both prior research and our study showed this relationship. In our study the participants generally showed high levels of self-efficacy and relatively low levels of strain. The strain that the participants were experiencing seems to be compensated by high levels of control of their work situation and the possibility of recovery. Thus it may be positive for an employer to promote a balance between demands and control. Further ahead it may be of interest to study the relation of cause between strain and self-efficacy as this was not possible in our study.

Streptomyces clavuligerus is a Gram-positive, filamentous bacterium which produces several important secondary metabolites, including isopenicillin N, cephamycin C and the &beta / -lactamase inhibitor clavulanic acid. Among these compounds, clavulanic acid is being used in combination with commonly used &beta / -lactam antibiotics in order to fight against bacterial infections that are resistant to such antibiotics. Among these combinations, Augmentin, composed of amoxicillin and clavulanic acid, is the most widely prescribed drug and has a market value of more than one billion dollars per year. There are two genes that act in regulation of clavulanic acid biosynthesis: ccaR located in cephamycin C gene cluster and claR located in clavulanic acid gene cluster. The goal of this study is to improve clavulanic acid production capacities of both wild type and industrial S. clavuligerus strains by integrating extra copies of claR gene into S.clavuligerus genome and its overexpression via a multicopy plasmid. Although previously has shown to be quite effective on wild type S. clavuligerus strains, claR overexpression in the industrial strain used in this study yielded only 1.4-fold increase in volumetric and 1.7-fold increase in specific CA production by the recombinant strains MA28 and MA16, respectively.

AbstractThe Iosipescu shear test, also known as asymmetric four point bending of a V-notched beam,is frequently used for measuring in-plane shear properties of composites. The ASTM standard(ASTM D-5379-05) regulates how the test is to be performed. It prescribes a notch openingangle of 90° independently of the material tested, although this has proven to produceinhomogenous strain distributions in the test region (between the notches) for orthotropicmaterials. Commonly, strain gauges are attached in the center of the test region where thedeviation from average strain is high. Thus, systematic errors in the measurement in the rangeof 10% or more may be introduced. The modified Iosipescu shear test, presented in this thesis, uses a variable notch opening angledepending on the material orthotropy and orientation to accomplish even stress- and strainfields in the test region. The variable notch opening angle accommodates both anisotropicmaterials and their orientation. Based on an elastic rescaling theory for orthotropic materials,the geometry was rescaled to recreate the same stress distribution in the test region as forisotropic materials. Specifically the notch opening angle was rescaled depending on theorthotropic ratio, the ratio of the two in-plane principal stiffnesses (Ex/Ey), to obtain theoptimal notch geometry. The rescaling procedure has been verified numerically with FEsimulationsand experimentally for several materials of different orthotropic ratio showingthat this was a very feasible method. Using a whole field optical measurement system duringtesting, significantly more homogenous strain fields were observed than for the standardspecimen geometry. Thus, there is no longer any need for correction factors, relying on FEsimulation,to obtain correct shear moduli. Constitutive shear properties and strength can thusbe more accurately measured, more completely and with fewer sources of error. Notablyhigher shear strengths at larger strains were also recorded compared to standard testing.The function of the new fixture was evaluated and compared with the standard Wyomingfixture. Combined in-situ 3D deformation measurements of both the new fixture and thespecimen showed that out of plane specimen deformation was very low and substantiallylower than the Wyoming fixture. Thus considerably lower parasitic stresses are introducedwith the new fixture. Recommendations regarding fastening of the specimen were determined based on simpleanalysis combined with FE-calculations and experiments. For both isotropic and orthotropic itwas found favorable if the clamp load used to hold the specimen and the expected net peakload and were set about equal. This reduces the risk of failure outside the test region bycrushing, brushing, splitting and etc. The same effects as shown in the FE-simulations werealso observed experimentally and of similar relative magnitude.Problems with differences in strains arising on the front and back face of the specimen duringtesting have been frequently reported in the literature. This is believed to stem from deviationsfrom nominal specimen geometry such as non-parallel and/or non-perpendicular boundingsurfaces. Three types of these combinations were evaluated numerically and the two mostsignificant were confirmed experimentally. The most critical geometrical deviation assessedwas a specimen with slightly conical cross section in the gripping region. For both isotropicand orthotropic materials, very small deviations from nominal geometry, caused unacceptablylarge errors in measurements of constitutive behavior / QC 20100827

Pain and disorders of the human skeletal muscles are one of the most common reasons for medical consultations in the western countries today and there is a great need to improve both the understanding and treatment of several different muscular conditions. Techniques describing the muscle function in vivo are often limited by either their invasiveness or lack of spatial resolution. Electromyography (EMG) is the most common approach to assess the skeletal muscle function in vivo, providing information on the neurological input. However, the spatial resolution is in general limited and there are difficulties reaching deep musculature without using invasive needles. Moreover, it does not provide any information about muscle structure or mechanical aspects. Quantitative ultrasound techniques have gained interest in the area of skeletal muscles and enables non-invasive and in-vivo insight to the intramuscular activity, through the mechanical response of the activation. However, these techniques are developed and evaluated for cardiovascular applications and there are important considerations to be made when applying these methods in the musculoskeletal field.  This thesis is based on the work from four papers with the main focus to investigate and describe some of these considerations in combination with the development of processing and analyzing methods that can be used to describe the physiological characteristics of active muscle tissue. In the first paper the accuracy of the Doppler based technique Tissue Velocity Imaging (TVI) was evaluated in a phantom study for very low tissue velocities and the effect of the pulse repetition frequency was considered. The second paper presents a biomechanical model to describe the TVI strain’s dependency on the muscle fiber pennation angle. In the third and fourth papers the intramuscular activity pattern was assessed through the regional tissue deformation by motion mode (M-mode) strain imaging. The activity patterns were analyzed during force regulation and for the effects of fatigue. The work of this thesis show promising results for the application of these methods on skeletal muscles and indicate high clinical potential where quantitative ultrasound may be a valuable tool to reach a more multifaceted and comprehensive insight in the musculoskeletal function. However, the methodological considerations are highly important for the optimized application and further evaluation and development of analyzing strategies are needed. / <p>QC 20130516</p>

Nearly one third of the 604,426 bridges in the United-States are either structurally deficient or functionally obsolete. Monitoring these bridges is essential to avoid catastrophic accidents. In steel bridges fatigue induced crack/rupture, which is one of the most common modes of failure, can be avoided if the crack is detected at the early stages of its formation. Cracks usually originate at stress concentration areas but their precise origin is random. Such strain concentration can be monitored with traditional strain gages, but their installation requires lengthy wires and equipment, which are expensive and labor intensive. Therefore wireless sensors are being developed to cope with these problems. In this work, a passive wireless strain sensor based on RFID technology is described. The sensor is a patch antenna that resonates at a certain frequency, which shifts in presence of strain. The relation between the resonance frequency and the strain is approximately linear. The slope of the relation is called sensitivity. The behavior of the sensor's sensitivity is studied using experimental work and simulations that couple electromagnetism and mechanics. The sensitivity measured in experiments and in simulations in presence of uniform strain is different. This difference is lower for the sensitivity in presence of a crack, probably due to a parameter variation that is currently not accurately modeled in the simulations.

As one category of energetic materials, impact-initiated reactive materials are able to release a high amount of stored chemical energy under high strain rate impact loading, and are used extensively in civil and military applications. In general, polymers are introduced as binder materials to trap the reactive metal powders inside, and also act as an oxidizing agent for the metal ingredient. Since critical attention has been paid on the metal / metal reaction, only a few types of polymer / reactive metal interactions have been studied in the literature. With the higher requirement of materials resistant to different thermal and mechanical environments, the understanding and characterization of polymer / reactive metal interactions are in great demand. In this study, PTFE (Polytetrafluoroethylene) 7A / Ti (Titanium) composites were studied under high strain rates by utilizing the Taylor impact and SHPB tests. Taylor impact tests with different impact velocities, sample dimensions and sample configurations were conducted on the composite, equipped with a high-speed camera for tracking transient images during the sudden process. SHPB and Instron tests were carried out to obtain the stress vs. strain curves of the composite under a wide range of strain rates, the result of which were also utilized for fitting the constitutive relations of the composite based on the modified Johnson-Cook strength model. Thermal analyses by DTA tests under different flow rates accompanied with XRD identification were conducted to study the reaction mechanism between PTFE 7A and Ti when only heat was provided. Numerical simulations on Taylor impact tests and microstructural deformations were also performed to validate the constitutive model built for the composite system, and to investigate the possible reaction mechanism between two components. The results obtained from the high strain rate tests, thermal analyses and numerical simulations were combined to provide a systematic study on the reaction mechanism between PTFE and Ti in the composite systems, which will be instructive for future energetic studies on other polymer / reactive metal systems.

No description available.

Fatigue failures of driveline and suspensions components for ground vehicles under multiaxial loading conditions are common, since most those components are subjected to complex multiaxial loadings in service. In addition to the multiaxial loadings, many of those components contain notches and geometrical irregularities where the fatigue failure often occurs due to stress concentrations. Therefore, the origins of the multiaxiality can be related to various combinations of external loadings and notch geometries. A computational fatigue analysis methodology has been proposed here for performing multiaxial fatigue life prediction for notched components using analytical and numerical methods. The proposed multiaxial fatigue analysis methodology consists of an elastic-plastic stress/strain model and a multiaxial fatigue damage parameter. The multiaxial stress-strain notch analysis method originally proposed by Buczynski and Glinka is adapted to develop the elastic-plastic stress/strain model to compute local stress-strain responses using linear elastic FE results of notched components. An original multiaxial fatigue damage parameter based on the maximum fatigue damage plane is proposed to predict the fatigue life for notched components under multiaxial loadings. Results of the proposed multiaxial fatigue analysis methodology are compared to sets of experimental data published in the literature to verify the prediction capability of the elastic-plastic stress/strain model and the multiaxial fatigue damage parameter. Based on the comparison between calculated results and experimental data, it is found that the multiaxial elastic-plastic stress/strain model correlates well with experimental strain data for SAE 1070 steel notched shafts subjected to several non-proportional load paths. The proposed multiaxial fatigue damage parameter, when applied to the uniaxial loading to account for the mean stress effect on fatigue life, is found to correlate very well with four sets of experimental uniaxial mean stress fatigue data. In the case of multiaxial loadings, the proposed multiaxial fatigue damage parameter provides very good correlation with experimental fatigue data of thin-walled tube specimens of 1045 steel and Inconel 718. In addition, the proposed fatigue damage parameter is found to correlate reasonably well with experimental fatigue data of SAE 1045 steel notched shafts subjected to proportional and non-proportional loadings. The proposed multiaxial fatigue analysis methodology enables rapid durability evaluation for notched components design. The effect of changes in material, geometry and loads on the fatigue life can then be assessed in a short time frame. The proposed multiaxial fatigue analysis methodology provides more efficient and appropriate analysis methods preferable to very expensive experimental durability tests and more complex and time consuming life prediction methods using non-linear FE stress-strain analysis.

When producing thermomechanical pulps (TMP), wood chips and fiber material are loaded mechanically in a disc-refiner to separate the fibers and to make them flexible. In the process, much of the energy supplied is transferred to the fiber material through cyclic compression, shear and friction processes. Therefore, compression and friction characteristics are needed in order to gain a better grasp of the forces acting during refining. To this end, in this thesis, the compressive and frictional behaviors of wood were investigated under simulated chip refining conditions (i.e., hot saturated steam, high strain rate compression, and high sliding speed). Two new, custom-designed, experimental setups were developed and used. The equipment used for compression testing was based on the split Hopkinson pressure bar (SHPB) technique and the friction tester was a pin-on-disc type of tribotester (wear rig). Both pieces of equipment allow a testing environment of hot saturated steam.   In the wood–steel friction investigation, the influence of the steam temperature (100-170°C) was of primary interest. The wood species chosen for the friction tests were spruce (Picea abies), pine (Pinus sylvestris, Pinus radiata), and birch (Betula verrucosa). When performing measurements in the lower-temperature region (100-130°C), the friction coefficients registered for the softwoods were generally low and surface properties such as lubrica­tion were suggested to have a great influence on the results; however, in the higher-tempera­ture region (~130 -170°C), the friction coefficients of all investigated wood species were probably determined by bulk properties to a much greater extent. When most of the wood extractives had been removed from the specimens, testing results revealed distinct peaks in friction at similar temperatures, as the internal friction of the different wood species are known to have their maxima at ~110–130°C. One suggested explanation of these friction peaks is that reduced lubrication enabled energy to dissipate into the bulk material, causing particularly high friction at the temperature at which internal damping of the material was greatest. During the friction measurements in the higher-temperature region, the specimens of the different wood species also started to lose fibers (i.e., produce wear debris) at different characteristic temperatures, as indicated by peaks in the coefficient of friction. In refining, the generally lower shives content of pine TMP than of spruce TMP could partly be explained by a lower wear initiation temperature in the pine species.   Wood stiffness is known to decrease with temperature, when measured at low strain rates. The results presented in this thesis can confirm a similar behavior for high strain rate compression. The compressive strain registered during impulsive loading (using a modified split Hopkinson equipment) increased with temperature; because strain rate also increased with temperature. Accordingly, the strain rates should determine the strain magnitudes also in a refiner, since the impulsive loads in a refiner are of similar type. Larger strains would thus be achieved when refining at high temperatures. The results achieved in the compression tests were also considered in relation to refining parameters such as plate clearance and refining intensity, parameters that could be discussed in light of the stress–strain relations derived from the high strain rate measurements. Trials recorded using high-speed photography demonstrated that the wood relaxation was very small in the investigated time frame ~6 ms. As well, in TMP refining the wood material has little time to relax, i.e., ~0.04–0.5 ms in a large single disc refiner. The results presented here are therefore more suitable for comparison with the impulsive loads arising in a refiner than are the results of any earlier study. It can therefore be concluded that the modified SHPB testing technique combined with high-speed photography is well suited for studying the dynamic behavior of wood under conditions like those prevalent in a TMP system.

The steel through-truss Traffic Bridge, located in Saskatoon, Saskatchewan is over one hundred years old. The bridge has been subject to ongoing maintenance throughout its service life. However, inspection reports from 2005 and 2006 highlighted the severe deterioration experienced primarily by the steel members immediately above and below the deck surface. These reports prompted the City of Saskatoon (COS) to implement a rehabilitation project that involved the installation of a post-tensioning system to relieve the badly corroded bottom chord members of the axial loads due to the self-weight of the structure, in 2006. Due to the severe deterioration and the structural modifications that the Traffic Bridge has endured, a limited scope structural health monitoring (SHM) system, based on strain measurements, was implemented to reduce some of the uncertainty regarding the active load paths occurring at the deck level. The objectives of the SHM study were to obtain more information regarding the actual load paths and ascertain possible types of structural redundancy, to determine how to best model this type of structure, and to find ways to track ongoing deterioration using instrumentation. The SHM study involved controlled truck loading scenarios to permit measurement of the load paths and provide data to compare the measured results to a finite element (FE) model of the instrumented span. In addition, random loading scenarios were used to capture the vertical dynamic response of the structure in order to further refine the FE model. This study focused on the response of one-half of one interior span. A total of 72 strain gauges were installed. The downstream truss was highly instrumented at ten locations, three members of the upstream truss were instrumented to measure the distribution, and the floor joists in the downstream lane were instrumented to establish possible redundancy paths. Using an FE model in combination with the measured strain data, it was found that redundant load paths only existed at the level of the deck. The bottom chord members experienced non-zero strains once the control vehicle was past the span, possibly indicating some level of redundancy. The members believed to relieve a portion of the bottom chord tensile forces included the car joists, edge joists, and the timber deck. The amount of force transferred from the bottom chord to the deck members was found by FE analysis to be highly related to the lateral stiffness of the floor beams. The FE model was adjusted to match the measured results by modifying various modelling parameters. The most important features of the model were that all deck elements were modelled to be located at the elevation of the bottom chord, that the lateral stiffness of the floor beams was reduced by 50% to best represent the transfer of forces to deck elements, and that the stiffness of bottom chord members was reduced to 80% of their pristine values. In combination with calibrated modification factors applied to the measured values, this FE model is believed to be a useful tool to represent the behaviour of the structure to assist in detecting further damage by modelling the strain differential between members, and components of members.