IF Steel to be used in this thesis which only have 50ppm carbon is approach Iron. It to be part of BCC. Because BCC material have much slip system when increase the cycle will induce to create multiple slip system. The dislocation structure often to become cell. We observation the same result of SEM and TEM in low cycle fatigue. The cell size is small in high plastic strain amplitude. The cell size is big in low strain amplitude. The difference of dislocation structures in front of crack tip which obtained under propagation rates o f 10-4, 10-5, 10-6 and 10-7 mm/cycle is the volume percentage occupied by the dislocation structures viz. misorientation cell, cell, wall, PSBs.

<p><em>Bakgrund: </em>Sömnen är viktig för att människan ska kunna fungera optimalt. Nattetid utsöndras hormonet melatonin som gör kroppen trött, vilket försvårar skiftarbete. Några av världens största olyckor har skett under just de timmar kroppen biologiskt är som svagast. Att vara trött kan även jämföras med att ha en mindre mängd promillehalt av alkohol i blodet.<em>Syfte:</em><strong> </strong>Syftet med studien var att beskriva hur sömnbrist hos omvårdnadspersonal påverkar vårdkvalitén och därmed patientsäkerheten<strong></strong><em>Metod:</em> Uppsatsen gjordes som en litteraturstudie där elva vetenskapliga artiklar genomförda med antingen kvantitativ eller kvalitativ metod inkluderades. Artiklarna kvalitetsgranskades och analyserades med hjälp av en analysmall.<strong></strong><em>Resultat:</em><strong> </strong>Av analysen framkom att långa arbetspass ledde till sömnbrist som i sin tur påverkade patientsäkerheten negativt då risken för att omvårdnadspersonalen skulle göra misstag ökade. <strong></strong><em>Slutsats:</em><strong> </strong>Roterande skiftjobb och nattskiftsarbete är oundvikligt inom sjukvården då många av patienterna behöver vård dygnet runt. Sömnbrist är ett problem värt att uppmärksammas då det ger konsekvenser för både personal och patienter. Att vara ouppmärksam är en del av sömnbristen och det kan orsaka patienterna vårdlidande när omvårdnadspersonalen begår onödiga misstag.</p>

Thesis (M.A.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 125-146). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38781

Physical inactivity is a major risk factor for chronic disease; yet the majority of the population does not meet physical activity recommendations, with fatigue being a primary underlying reason. Common nutritional supplements such as caffeine (CAF) and carbohydrate (CHO) are frequently taken prior to and during exercise and can delay fatigue, particularly in trained athletes; but, whether these same reductions in fatigue translate to habitually sedentary individuals is less clear. The main goal of this research was to investigate the influence of nutritional aids: CAF, low-calorie CHO, and their combination CAF+CHO to delay physical and mental fatigue in healthy but sedentary men and women compared to endurance-trained counterparts. The minimum amount of CHO that could elicit a benefit without eliciting a metabolic response when ingested remains unclear. Thus, our first aim was to evaluate glycemic response after ingestion of CHO drinks ranging from 0-6% CHO; and, to determine effects of two methods of CHO administration (ingest and oral rinse without ingestion) on sustained attention during a mentally fatiguing cognitive task. In agreement with evidence that “low calorie beverages” do not appear to alter blood glucose, a 0.4% CHO solution (<2 g CHO) elicited the most similar response to artificially sweetened placebo and was evaluated further. Compared to oral rinse of a small amount (<2 g) of CHO or control (0 g CHO), ingestion of an equivalent “dose” (<2 g CHO) in the 0.4% CHO solution maintained sustained attention, providing evidence that ingesting a low-CHO drink may be more effective than simply rinsing, in a fasted state. Oral rinse of CHO did not, however, provide any benefit compared to rinsing a control solution. Our second aim was to evaluate the efficacy of ingesting a moderate dose of CAF (3 mg/kg), low-CHO, and the combination of CAF+CHO on exercise capacity in trained (ET) versus sedentary (SED) groups. As expected, CAF reduced perceived effort during exercise and increased endurance capacity (longer total time to volitional fatigue and longer duration before rating vigorous intensity exercise as “very hard”), for ET and SED. However, addition of <2 g CHO did not provide further improvement with CAF; or any benefit when ingested alone, compared to placebo. CAF and CHO did not influence blood glucose but CAF resulted in higher blood lactate compared to no-CAF. As expected, ET had higher fat oxidation than SED; and, CAF increased CHO oxidation but not fat oxidation. CAF tended to maintain maximal voluntary contractile (MVC) strength in the quadriceps after exercise; but, CAF did not influence voluntary muscle activation or appear to have a direct effect on skeletal muscle since electrically evoked strength was not altered with CAF. Since acute exercise also benefits cognition independent of CAF or CHO, our third aim was to determine: (1) the effect of moderate intensity exercise (MOD-EX) on sustained attention in comparison to seated rest; and 2) whether CAF provides additional benefit to sustained attention and perceptual measures when combined with exercise. As expected, compared to an equivalent duration of rest, MOD-EX improved sustained attention following mental fatigue in both groups; and, when coupled with CAF, provided greater benefit to sustained attention and perceived mental energy. Although CAF’s beneficial effect on sustained attention persisted after exercise to volitional fatigue, it did not improve perceptual measures of reduced mental energy and increased mental fatigue at the point of physical fatigue. Our research investigated nutritional aids that are not only beneficial for athletes, but also widely consumed by the general population despite their lack of regular physical activity. In response to public health recommendations for reducing sugar intake, low-sugar/low-calorie drinks have been heavily marketed to the population despite much research to support their efficacy. Our findings suggest that low-CHO can be ergogenic during a sedentary mental task in a fasted state, perhaps through central mechanisms. Although CHO mouth rinse is evidenced to be efficacious for exercise performance without ingestion, we did not find that ingestion of low-CHO provides any significant benefit during moderate to vigorous exercise following a small meal. However, a moderate dose of CAF was ergogenic for both ET and SED. Future work should not only investigate additional exercise interventions; but also different CHO and CAF doses and administration protocols, and their relative metabolic implications.

This study presents a test and analysis method to determine both damage and healing characteristics of asphalt composites using the same test specimen. The test involves applying multiple stretches of load cycles, each separated by a period of zero load introduced at several different levels of reduced stiffness. The analytical procedure involves (1) using modified correspondence principles to transform the time-dependent physical quantities (stress, strain and energy density) into time-independent pseudo-elastic quantities, and then (2) using viscoelastic continuum damage mechanics to quantify damage and healing properties of the material based on the transformed quantities. The results obtained using two different asphalt mortars subjected to uniaxial and shear load cycles confirmed the findings from the previous researchers that the characteristic pseudo stiffness versus damage relationship for a given material is independent of testing conditions. More importantly, this study demonstrated that the aforementioned relationship was also independent of the rest periods introduced intermittently during the cyclic tests. Results also show that healing defined in terms of the change in the internal state variable for damage represents the true healing potential of a material. Furthermore, healing properties obtained using the proposed test method (a) agreed with the properties obtained using a more rigorous protocol with multiple test specimens, and (b) were independent of the loading conditions used to induce fatigue damage. These observations strongly suggest that the proposed method can be used to predict damage and healing properties for any arbitrary loading condition from properties determined using the proposed protocol. / text

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

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