80 research outputs found

    Relation of size distribution of cracks in superconducting layer to critical current distribution under small voltage probe spacing in rebco-superconducting composite tape

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    The relation of distribution of crack size to that of critical current under small voltage probe spacing in RE(Y, Sm, Dy, Gd, ….)Ba2Cu3O7−δ layer-coated superconducting tape with stress-induced cracks was studied with a Monte-Carlo simulation method in combination with a model of current shunting at cracks. First, it was shown that the experimentally observed feature that the critical current decreases with increase in distribution width of crack size and voltage probe spacing was reproduced by the present simulation. Then it was revealed that (i) the largest crack among all cracks in the region between the voltage probes plays a dominant role in determination of critical current, and, (ii) when the size of the largest crack is fixed, the large difference in crack size among all cracks acts to raise the critical current value and to reduce the n-value, and, in this phenomenon, the reduction of n-value with increasing difference in crack size is more dominant than the increase of critical current. Finally, it was shown that the distribution of critical current can be described using the Gumbel’s extreme value distribution function as a first approximation under small voltage probe spacing where the influence of the difference in crack size on critical current is relatively small

    Mechanical and Superconducting Properties of Multifilamentary Nb₃Sn Composites

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    The interrelation of mechanical and superconducting properties with the microstructure of multifilamentary composites has been investigated. The fracture behaviour changed depending on the growth of the compound layer. When the layer is thin, multiple fracture is observed and the composite can be plastically deformed with a large elongation. On the other hand, when the heat tratment progresses and the layer thickness becomes thicker, the whole composite fractures at once after a small elastic elongation. There exists a critical thickness dividing these two modes, which has been determined theoretically as well as experimentally. The maximum global pinning force can be well described as a function of the inverse grain size of the compound. The strength of the compound is also made clear so as to be expressed as a function of the inverse grain size. Finally, we propose the structure of composites and the conditions of heat treatment to optimize both properties mentioned above

    Elämäntapatutkimus kauneudenhoitoalan opiskelijoille

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    Tämän opinnäytetyön tarkoitus on selvittää kauneudenhoitoalan opiskelijoiden elämäntapoja ja analysoida niiden vaikutuksia koulussa jaksamiseen sekä opintojen etenemiseen. Opinnäytetyö on tehty yhteistyössä Stadin ammattiopiston kauneudenhoitoalan koulutusyksikön kanssa. Tutkimuksen tavoite on tuoda esille elämäntapojen vaikutus opintoihin, ja mahdollisesti saada nuoret opiskelijat ymmärtämään valintojensa merkitys. Elämäntavat näkyvät väistämättä jokaisen ihmisen arjessa, ja nuorena opitut tavat jatkuvat monesti myös aikuisiällä. Asioiden merkitys on hyvä ymmärtää jo nuorena rakennettaessa tulevaisuutta kouluttautumalla työelämään. Tutkimuksessa kävi ilmi, että elämäntavat vaikuttavat nuorten opintoihin tutkimustulosten perusteella vähemmän kuin ennakko-oletuksena oli. Vastausten mukaan kauneudenhoitoalan opiskelijoiden elämäntavat ovat melko hyvät, eikä heillä juurikaan ole poissaoloja koulusta huonojen elintapojen seurauksena. Kuitenkin esille nousi se, että mikäli poissaoloja koulusta on kertynyt, vaikuttaa se opiskelumotivaatioon ja opintojen etenemiseen. Päällimmäisenä tutkimuksessa nousi esille, että selkein syy poissaoloihin vaikuttaisi tutkimuksen mukaan olevan unenpuute, jota esiintyi noin puolella vastaajista. Suurimmalla osalla opiskelijoista ei ole säännöllistä vuorokausirytmiä, vaikka opiskelu tapahtuu arkipäivisin samaan aikaan. Unen määrän ja laadun koetaan myös vaikuttavan opinnoissa jaksamiseen. Noin puolella vastaajista ei myöskään ole säännöllistä ruokailurytmiä, mutta sen ei koeta kuitenkaan juurikaan vaikuttavan opintoihin negatiivisesti. Tutkimuksen tuloksia voidaan hyödyntää ammatillisissa oppilaitoksissa, kun pyritään ymmärtämään opiskelijoiden opinnoissa jaksamisen syitä sekä opiskelumotivaatiota.Survey of lifestyle habits among beauty care students The purpose of this thesis was to survey the beauty care students’ lifestyle habits and analyse the effects of those habits on the students’ well-being and performance at school. The thesis was done in cooperation with Helsinki Vocational College. The aim of this study was to find out how lifestyle habits affect the studies and hopefully make the young students understand the implications of their choices. The lifestyle choices have a great impact on how we live and the habits adopted early are often carried into adulthood. The significance of one’s choices is important to take into account when getting ready for the future job market. According to the results of this study, lifestyle habits affect the students’ performance less than was assumed. The results showed that the beauty care students’ lifestyle habits are quite good and they did not have many lifestyle related absences from classes. Yet, when absences pile up, it implies problems concerning motivation and advancement in studies. The main finding was that the most common reason for absences is sleep deprivation, which was experienced by half of the students who participated in this study. The majority of the students did not have a regular daily rhythm even though they studied daily at regular times. The quantity and quality of sleep were seen as affecting the studies. About half of the respondents did not have a regular dietary schedule either, but it was not seen as affecting the studies negatively. The results of this study can be used at vocational colleges when trying to understand the issues related to the students’ performance and motivation in studies

    Point-focusing monochromator crystal realized by hot plastic deformation of a Ge wafer

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    A point-focusing Johansson monochromator crystal prepared by hot-pressing a Ge single-crystal wafer is demonstrated. By using 333 diffraction, Cu Kα radiation was focused onto a small spot

    A Trial on Detecting Fluctuations in Bulk Metallic Glass Beams by Strain Contrast Variation Method-Use of High Energy Small-Angle Scattering

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    Heterogeneity in annealed Zr-Cu-Al alloys with high ductility has been examined by high-energy small-angle scattering with strain variation method. Although the statistics is still poor for detailed analysis, it was found that the heterogeneity in the sample showed clear enhancement by applied tensile strain, and the characteristic size of the heterogeneity was of the same order of magnitude as the one observed by high resolution electron microscopy. With surface insensitivity of the present method, anomalous small-angle scattering results at Cu K absorption edge for the same sample was briefly discussed

    Kannattavuuden arviointi yksityismetsätaloudessa

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    Opinnäytetyön tavoitteena oli kannattavuuden arviointi esimerkkitilalla metsätalouden ohjelmistoja hyödyntäen ja arvioida ohjelmistojen soveltuvuutta yksityismetsätalouden käyttöön. Työn teoriaosuuteen perehdyttiin tutustumalla Suomen metsävaroihin ja metsänomistajarakenteeseen. Met-sätalouden kannattavuuden perustana olivat teoriapohja liittyen metsätalouden tuloihin, menoihin ja verotukseen. Työssä aineistona käytettiin vuonna 2015 laadittua metsäsuunnitelmaa. Tutkimusmenetelminä olivat esimerkkitilan kannattavuuden arviointi Metsätalouden kannattavuuslaskuria ja Motti-ohjelmistoa hyödyntäen. Metsätalouden kannattavuuslaskurin avulla laadittiin yhteenveto metsätilan taloudellisista tunnusluvuista, taselaskelmasta, tuloslaskelmasta ja kassavirran kehityksestä. Motti-ohjelmistolla laadittiin esimerkkitilan edustaville kuvioille kehitysennusteet ja selvitettiin erilaisten metsänkäsittelytoimenpiteiden taloudellista kannattavuutta. Keskimääräinen liiketulos metsätilalla oli 10 073 euroa vuodessa. Metsätilan hehtaarikohtainen liiketulos oli 45 euroa vuodessa. Metsätilan kirjanpidon tulos säilyi positiivisena lukuun ottamatta tarkastelujakson viimeistä vuotta, jolle ei ajoittunut metsäsuunnitelman mukaisia hakkuita. Esimerkkitilalla kannattavuutta voitaisiin parantaa tekemällä osa metsänhoitotöistä omatoimisesti ostopalvelun sijasta. Metsätalouden kannattavuuslaskurin todettiin soveltuvan kannattavuuden tarkasteluun tilatasolla. Metsätalouslaskurin edellyttämä metsäsuunnitelma mahdollistaa mahdollisimman luotettavan kannattavuuden arvioinnin. Epävarmuustekijöinä laskelmissa on rahavirtojen perustuminen pitkän ajan indekseihin. Motti-ohjelmisto soveltuu erilaisten metsänkäsittelyvaihtoehtojen vertailuun ja niistä aiheutuvien kustannusten arviointiin kuviotasolla. Motti-ohjelman epävarmuustekijänä on puuttuva mahdollisuus simuloida luonnon tai ihmisten aiheuttamien tuhojen vaikutusta metsikön kasvuun.The purpose of this thesis was to estimate profitability in a certain forest holding using silvicultural softwares and evaluate their suitability for use in forestry. The theory part handles Finnish forest resources and forest ownership structure. The profitability of forest holdings was based on the theory in incomes, expenses and taxes. The material for the thesis was a forest management plan that was made in 2015. The thesis consisted of the evaluation of the profitability in one forest holding using a profitability calculation programme and Motti-software. With the profitability calculation programme a summary of the financial figures, balance sheets, income statements and cash flow developments in forest holdings was done. Motti-software was used to make development predictions in the representative compartments and estimate the economic viability of silvicultural works. The average business result in the forest holding was 10 073 euros per year. The average business result per hectare was 45 euros. The turnover of the forest holdings remained positive in the whole period expect the last year, because there were no fellings according to the forest management plan. The profitability of the forest holdings can be improved by making part of the silvicultural work on your own instead of buying the service. The Profitability calculation programme was suitable for examining the profitability at the forest holding level. Because the software requires a forest management plan, the profitability can be estimated as reliably as possible. The uncertainty in the calculations is based on long term esti-mates in cash flows. Motti-software is suitable for comparing silvicultural works and fellings at a compartment level. Motti-software does not have an option to simulate natural or human damage to the development of a forest stand

    Interleukin-17 Promotes Autoimmunity by Triggering a Positive-Feedback Loop via Interleukin-6 Induction

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    Tensile deformation and failure behavior at room temperature of the open cell nickel and copper foams with high porosity (96%) fabricated with the slurry foaming process at Mitsubishi Materials Corporation, Japan, was studied. In-situ observation of the deformation and failure behavior was conducted with a digital microscope. Stress-strain curves were measured, in which a non-contact extensometer was employed to detect the strain of the samples accurately. Electric resistance was measured to monitor the damage evolution. Finite element stress analysis was conducted to calculate the morphological change of cells with applied strain and the stress distribution in cells. It was revealed that the deformation and failure progressed through the following four stages; stage I characterized by the elastic deformation, stage II by plastic deformation, stage III by the co-occurrence of plastic deformation and cumulative failure of struts and stage IV by the chain reaction of strut failure nearly in a limited cross-section, respectively. Also it was found that the distribution of failure strain of struts in stage III, measured from the serrations in the stress-strain curve, could be described by the Weibull distribution, with which the transition from stage II to III was identified. Also, the result of the statistical analysis suggested that the average failure strain of the struts in the foam is much higher than the strain at ultimate stress of the foam

    Management of Acute Superior Mesenteric Artery Occlusion by Thrombolytic Therapy

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    Acute occlusion of the superior mesenteric artery (SMA) causes extensive bowel necrosis, resulting in a poor prognosis with an extremely high mortality rate. An 82-year-old woman was admitted to our hospital with the complaint of abdominal pain. She was diagnosed as having acute SMA occlusion by enhanced CT. Five hours from onset, the first thrombolytic therapy with urokinase was performed, but failed to complete thrombolysis and recanalization of peripheral blood flow. An exploratory laparotomy following the first thrombolytic therapy showed a mild ischemic change in the affected intestine and mesentery, but no sign of necrosis. After the laparotomy, local thrombolytic therapy with angiographic evaluation of blood flow at 24, 36 and 48 h from the first thrombolysis was performed. As a result, the residual thrombus disappeared and all branches of the SMA became well visualized. The patient was discharged well without a second-look operation or major bowel resection. Sequential intermittent thrombolytic therapy with meticulous angiographic evaluation of blood flow is effective for early-stage acute SMA occlusion
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