Superconductivity in CoSr2(Y1-xCax)Cu2O7+d

The roles of aliovalent Ca(II)-for-Y(III) substitution and high-pressure-oxygen annealing in the process of "superconducterizing" the Co-based layered copper oxide, CoSr2(Y1-xCax)Cu2O7+d (Co-1212), were investigated. The as-air-synthesized samples up to x = 0.4 were found essentially oxygen stoichiometric (-0.03 <= d <= 0.00). These samples, however, were not superconductive, suggesting that the holes created by the divalent-for-trivalent cation substitution are trapped on Co in the charge reservoir. Ultra-high-pressure heat treatment carried out at 5 GPa and 500C for 30 min in the presence of Ag2O2 as an excess oxygen source induced bulk superconductivity in these samples. The highest Tc was obtained for the high-oxygen-pressure treated x = 0.3 sample at ~40 K.Comment: 16 pages, 6 figures, submitted to Solid State Communication

Oxygen non-stoichiometry in Ru-1212 and Ru-1222 magnetosuperconductors

Here we report the results of thermogravimetric (TG) analysis on the oxygen non-stoichiometry of RuSr2GdCu2O8 (Ru-1212) and RuSr2(Gd0.75Ce0.25)2Cu2O10(Ru-1222) samples. With TG annealings carried out in O2 and Ar atmospheres it was found that the oxygen content in Ru-1212 remains less affected upon various annealings, while for Ru-1222 wider-range oxygen-content tuning is possible. When heated in H2/Ar atmosphere the both phases release oxygen upon breaking down to mixtures of metals (Ru and Cu) and binary oxides (CeO2, Gd2O3, and SrO) in two distinct steps around 300 and 450 oC. This reductive decomposition reaction carried out in a thermobalance was utilized in precise oxygen content determination for these phases. It was found that the 100-atm O2-annealed Ru-1212 sample was nearly stoichiometric, while the similarly treated Ru-1222 sample was clearly oxygen deficient. X-ray absorption near-edge (XANES) spectroscopy was applied to estimate the valence of Ru in the samples. In spite of the fact that the Ru-1212 phase was shown to possess less oxygen-deficient RuO2 layer, the valence of Ru as probed with XANES was found to be lower in Ru-1212 than that in Ru-1222.Comment: 11 pages text, 4 pages Figs. To ISS 2002 YOKOHAMA for PHYSICA

Enhanced thermoelectric properties of NaxCoO2 whisker crystals

Single-crystalline whiskers of thermoelectric cobalt oxide, NaxCoO2, have been grown by an unconventional method from potassium-containing compositions, and their transport properties, and chemical compositions were determined. The growth mechanism was analyzed and interpreted by means of thermogravimetric analysis. At 300 K, electrical resistivity r and thermoelectric power S of the whisker are 102 u ohm cm and 83 uV/K, respectively. The power-factor, S2/r, thus is enhanced up to ~ 68 uW/K2 cm.Comment: 8 pages, 4 figures, to appear in Appl. Phys. Let

Sensitivity of soil phosphorus tests in predicting the potential risk of phosphorus loss from pasture soil

The objective of this study was to examine the effects of urine and dung additions on the phosphorus (P) chemistry of pasture land and to compare the sensitivity of two soil extraction methods in assessing the P-loading risk. In a field experiment, urine and dung were added to soil in amounts corresponding to single excrement portions and the soil samples, taken at certain intervals, were analysed for pHH2O, acid ammonium acetate extractable P (PAc) and water extractable total P (TPw), and molybdate reactive P (MRPw). Urine additions immediately increased soil pH and MRPw, but no such response was observed in PAc extraction due to the low pH (4.65) of the extractant enhancing the resorption of P. The PAc responded to the dunginduced increase in soil total P similarly as did Pw, which suggests that both tests can serve to detect areas of high P concentration. However, water extraction was a more sensitive method for estimating short-term changes in P solubility. In pasture soils, the risk of P loss increases as a result of the interaction of urination and high P concentration in the topsoil resulting from continuous dung excretion

Kollektiivisen liikkeen ohjaaminen

Collective motion is an umbrella term for both biological and non-organic coherent motion, in which tens to tens of millions units take part in. The huge fish schools that fishing ships pursue and the nightmarish legions of locusts which destroy entire countries' worth of crops are just a few examples of collective motion in nature that have a direct effect on us humans. This thesis focuses on the complex behavior of collective motion and studies how such movement can be steered. As a tool, the original Vicsek model for simulating collective behavior is used. An agent-based model, the Vicsek model was introduced in 1995 and has been extensively utilized and studied since. The Vicsek model consists of units that move independently but prefer to take the common movement direction of their neighbors. Although it is a simplified model, the Vicsek model exhibits flocking behavior that is similar to what is observed in nature. The results of this thesis show that in this context, collective motion of hundreds of units is greatly affected by just a small percentage of special units, called leaders. The leaders don't adhere to the common rules of the other units, but move in a constant direction. It is observed that the relative amount of leaders needed to steer the entire flock actually decreases as the flock size grows or if we wait sufficiently long. This leads to the conclusion that in the limit of an infinite system size, a finite amount of leaders would suffice to control the flock.Kollektiivinen liike on kattotermi sekä biologiselle että ei-orgaaniselle koherentille liikkeelle, johon osallistuu kymmenistä kymmeniin miljooniin yksikköä. Luonnossa esiintyvä kollektiivinen liike vaikuttaa suoraan meihin ihmisiinkin, kuten esimerkiksi kalastuslaivastojen metsästämät kalaparvet tai valtavat kulkusirkkaparvet jotka tuhoavat kokonaisten valtioiden viljasatoja osoittavat. Tämä diplomityö keskittyy kollektiivisen liikkeen kompleksiseen käytökseen sekä tutkii kuinka tällaista liikettä voidaan ohjata. Työkaluna käytetään kollektiivisen käytöksen simuloimiseen tarkoitettua Vicsekin alkuperäismallia. Vicsekin malli on agenttipohjainen malli joka esiteltiin vuonna 1995, ja jota on siitä lähtien käytetty ja tutkittu laajasti. Vicsekin malli koostuu yksiköistä jotka liikkuvat itsenäisesti, mutta suosivat läheisten yksiköiden keskimääräistä liikesuuntaa. Vaikkakin Vicsekin malli on yksinkertaistettu, sen tuottama parvikäytös vastaa luonnossa havaittavaa käytöstä. Tämän diplomityön tulokset osoittavat satojen yksikköjen kollektiivisen liikkeen käytöksen olevan riippuvainen vain pienen prosenttiosuuden muodostavien erityisten johtoyksiköiden käytöksestä. Johtoyksiköt eivät noudata samoja sääntöjä kuin muut yksiköt, vaan liikkuvat vakiosuuntaan. Kun parven koko kasvaa tai odotettaessa riittävän kauan, koko parvea ohjaamaan tarvittavien johtoyksiköiden suhteellinen lukumäärää vähenee. Tästä voidaan päätellä että äärettömän kokoisessa systeemissä äärellinen määrä johtoyksiköitä riittää kontrolloimaan koko parvea

Iron and molybdenum valences in double-perovskite (Sr,Nd)2FeMoO6: electron-doping effect

Double perovskite, (Sr1-xNdx)2FeMoO6, was doped with electrons through partial substitution of divalent Sr by trivalent Nd (0 < x < 0.2). The Fe valence and the degree of B-site order were probed by 57Fe Mossbauer spectroscopy. Replacing Sr by Nd increased the fraction of Fe and Mo atoms occupying wrong sites, i.e. antisite disorder. It had very little effect on the Fe valence: a small but visible increase in the isomer shift was seen for the mixed-valent FeII/III atoms occupying the right site indicating a slight movement towards divalency of these atoms, which was more than counterbalanced by the increase in the fraction of antisite Fe atoms with III valence state. It is therefore argued that the bulk of the electron doping is received by antisite Mo atoms, which - being surrounded by six MoV/VI atoms - prefer the lower IV/V valence state. Thus under Nd substitution, the charge-neutrality requirement inflicts a lattice disorder such that low-valent MoIV/V can exist.Comment: 15 pages, 6 figures, to appear in Solid State Commu

Terveysneuvontaa raskausdiabeteksesta somalinaisille

TIIVISTELMÄ Karppinen, Reeta. Terveysneuvontaa raskausdiabeteksesta somalinaisille. Helsinki, syksy 2012, 38 s., 7 liitettä. Diakonia-ammattikorkeakoulu, Diak Etelä, Helsinki, Hoitotyönkoulutusohjelma, Terveydenhoitaja (AMK). Raskausdiabetes on sokeriaineenvaihdunnan häiriö, joka esiintyy raskauden aikana. Viime vuosien aikana raskausdiabetes on lisääntynyt, noin puolella raskaana olevista on raskausdiabeteksen riskitekijöitä. Raskausdiabetesta hoidetaan ensisijaisesti ravitse-musohjauksella, ruokavaliohoidolla ja lisäämällä liikuntaa. Tämän opinnäytetyön tavoitteena oli antaa tietoa raskausdiabeteksesta somalinaisille. Opinnäytetyönä järjestettiin kolme terveysneuvontatuokiota. Terveysneuvontatuokiot toteutettiin PowerPoint-esityksen avulla, joissa kerrotaan millainen sairaus se on ja kuinka sitä hoidetaan. Opinnäytetyö toteutettiin yhteistyössä Setlementtiliiton Pasilan asukastalon kanssa. Terveysneuvontatuokioista kaksi järjestettiin Pasilan asukastalossa ja yksi Helsinki Islam Keskuksessa. Kolmeen terveysneuvontatuokioon osallistui yhteensä 80 somalinaista. Terveysneuvontatuokioiden sisältö koottiin aiheeseen liittyvästä kirjallisuudesta sekä tutkimustietoa hyväksi käyttäen. Opinnäytetyön teoriaosa sisältää tietoa terveyden edis-tämisestä, raskausdiabeteksesta ja ohjaamisesta. Terveysneuvontatuokioiden perusteella havaitsin, että somalinaiset olivat kiinnostuneita terveyteen liittyvistä asioista ja osallistuivat mielellään heille järjestettyihin tapahtumiin. Osallistujien suullisen palautteen perusteella tuokiot olivat onnistuneita ja somalinaiset saivat lisätietoa raskausdiabeteksesta. Parhaiten kohderyhmään kuuluvat tavoitti heidän omassa kokoontumispaikassaan. Avainsanat: ohjaus, raskausdiabetes, somalit, terveyden edistäminen, terveysneuvontaABSTRACT Karppinen, Reeta Guidance on gestational diabetes for Somali women. 38p., 7 appendices. Language: Finnish. Helsinki, Fall 2012. Diaconia University of Applied Sciences. Degree Programme in Nursing, Option in Health Care. Degree: Public Health Nurse. Gestational diabetes is a sugar metabolism disorder that exists during pregnancy. Gesta-tional diabetes has increased during recent years. Half of the pregnant women have a risk to get the disease. Gestational diabetes is treated by diet and exercise. The objective of this thesis was to provide advice on gestational diabetes to Somali women. The thesis consists of three health promotion lectures held at Pasilan asukastalo and Helsinki Islam Centre. Pasilan asukastalo is an open meeting place for the people living in Helsinki. This thesis is a product. In total, eighty Somali women participated in the lectures. The lectures were held in spring and fall 2012. The theoretical background of the study con-sists of contributing to health, gestational diabetes and guidance. The results of this thesis show that Somali women were interested in health matters. They participated eagerly in the health lectures. Based on the feedback, their experience was positive and their knowledge of gestational diabetes increased. There were 60 par-ticipants in the lectures that were held at Helsinki Islam Centre. According to the feed-back, it is easier for them to gather in a familiar place together with other Somali wom-en. This promoted their active participation. Keywords: gestational diabetes, Somali women, health promotio

Meteorological pre-processing and atmospheric dispersion modelling of urban air quality and applications in the Helsinki metropolitan area

This theses describes the boundary-layer parameterisation model, which is applied as a meteorological pre-processor by Finnish regulatory dispersion models. The parametrisation scheme is based on the energy-flux method, which evaluates the turbulent heat and momentum fluxes in the boundary layer. A comparison of the model predictions with those of the corresponding scheme of Berkowicz and Brahm, using the same synoptic input data is presented. The comparison shows the basic physical differences between these two models. Some numerical results calculated by these two pre-processors differ substantially, while the results for net radiation are statistically nearly identical. Meteorological profile data from Finnish sounding stations is compiled and the inversions (the temperature of the atmosphere increases with altitude) are classified according to the total depth of the inversion and the stability of the boundary layer, which was estimated directly from the temperature gradient in the layer from the ground up to 100 meters. The persistence of the inversions and the influence of cloudiness and wind speed on the temperature gradient are also addressed. The specific problems of an urban area is tackled, using measurements from a meteorological mast situated in the Helsinki metropolitan area by comparing them to those from the radiosonde profiles at the rural site of Jokioinen. Several common schemes for the height of the stable boundary layer are compared to results from our own method developed at Finnish Meteorological Institute (FMI). Based on this analysis a modification to the FMI method is suggested. An integrated modelling system for evaluating the traffic volumes, emissions from stationary and vehicular sources, and atmospheric dispersion of pollution in an urban area is described. The dispersion modelling is based on combined application of the Urban Dispersion Modelling system for stationary sources (UDM-FMI) and the road network dispersion model (CAR-FMI). The system includes also a meteorological pre-processing model (MPP-FMI) and a statistical and graphical analysis of the computed time series of concentrations. The modelling system contains a method, which allows for the chemical interaction of pollutants, originating from a large number of urban sources. An application of the integrated modelling system for estimating the NOx and NO2 concentrations in the Helsinki metropolitan area in 1993 is presented. The thesis finally presents a comparison of model predictions with the results of an urban measurement network.reviewe