Synthesis of FeCu Nanopowder by Levitational Gas Condensation Process

Condensation from the vapor state is an important technique for the preparation of nanopowders. Levitational gas condensation is one such technique that has a unique ability of attaining steady state. Here, we present the results of applying this technique to an iron-copper alloy (96Fe-4Cu). A qualitative model of the process is proposed to understand the process and the characteristics of resultant powder. A phase diagram of the alloy system in the liquid-vapor region was calculated to help understand the course of condensation, especially partitioning and coring during processing. The phase diagram could not explain coring in view of the simultaneous occurrence of solidification and the fast homogenization through diffusion in the nanoparticles; however, it could predict the very low levels of copper observed in the levitated drop. The enrichment of copper observed near the surface of the powder was considered to be a manifestation of the lower surface energy of copper compared with that of iron. Heat transfer calculations indicated that most condensed particles can undergo solidification even when they are still in the proximity of the levitated drop. It helped us to predict the temperature and the cooling rate of the powder particles as they move away from the levitated drop. The particles formed by the process seem to be single domain, single crystals that are magnetic in nature. They, thus, can agglomerate by forming a chain-like structure, which manifests as a three-dimensional network enclosing a large unoccupied space, as noticed in scanning electron microscopy and transmission electron microscopy studies. This also explains the observed low packing density of the nanopowders.

Flow structure and heat transfer characteristics behind a diaphragm in the presence of a diffusion flame

The characteristics of the separated flow behind a diaphragm over a burning surface are investigated experimentally. This complex problem of practical significance involving recirculation, blowing and combustion reactions is studied in a two-dimensional combustion tunnel. The flame structure, recirculation patterns and heat transfer to the surface are presented for a range of values of free stream and fuel injection velocities as well as for different heights of the diaphragm. The trends of heat transfer vs axial distance are shown to be similar to those resulting from a non-reactive heated stream with a diaphragm. Treating the case of a boundary layer diffusion flame as that corresponding to the zero height of the diaphragm, the heat transfer augmentation due to recirculation is estimated. It is found that at considerable downstream distances (xfh > 3), the heat transfer rates with diaphragm overtake the rates from a developing boundary layer case. Flow visualization studies with particle track photography show that there are many similarities between the reactive and the non-reactive cases.

Geriatrisen lääkehoidon koulutustarpeet perusterveydenhuollossa - Moniammatillisen täydennyskoulutuksen suunnittelu LOST-alueen kotihoidon henkilöstölle

Sosiaali- ja terveysministeriön 2006 julkaiseman vanhustyön ja geriatrisen lääkehoidon kehittämistä koskevan selvityksen yhtenä tärkeänä huolenaiheena oli iäkkäiden lääkehoidon useat epäkohdat, kuten iäkkäitä hoitavien hoitajien lääkeosaamiseen liittyvät puutteet ja ongelmat. Yksi keino parantaa iäkkäitä hoitavien eri tahojen lääkehoito-osaamista on täydennyskoulutus, johon kaikilla sosiaali- ja terveydenhuollon ammattiryhmillä on oikeus ja velvollisuus. Täydennyskoulutuksella pystytään myös kehittämään organisaatioiden toimintaa ja tuottamaan uusia, parempia palveluita. Tutkimuksessa selvitettiin Lohjan, Siuntion, Inkoon ja Karjalohjan muodostaman sosiaali- ja terveydenhuollon yhteistoiminta-alueen LOSTin kotihoidon yksiköiden iäkkäiden lääkehoitoihin liittyviä koulutustarpeita. Tämän tutkimuksen avulla syvennettiin samalle tutkimusryhmälle tehdyn kyselytutkimuksen tuloksia. Tutkimusaineistona käytettiin LOST-alueen kotihoidon yksiköiden hoitajille (n=150) farmaseutin lopputyönä tehtyä kyselyaineistoa sekä työntekijöille (n=6) ja esimiehille (n=6) tehtyjä erillisiä ryhmäkeskusteluja. Lisäksi näkökulman laajentamiseksi ja moniammatillisuuden korostamiseksi aineistona käytettiin kotihoidon asiakkaita hoitavien lääkärien (n=4) teemahaastatteluja. Kyselyaineistosta analysoitiin erikseen sairaanhoitajien, lähihoitajien ja kodinhoitajien koulutustarpeet. Samat asiat nousivat esille kunkin ammattiryhmän tuloksissa. Tärkeimpinä lääkehoito-osaamiseen liittyvinä teoreettisina koulutettavina asioina kyselystä nousivat esille iäkkäiden farmakokinetiikka ja lääkkeiden käyttöön liittyvät erityispiirteet, lääkkeiden vaikutukset, lääkkeiden haittavaikutukset sekä lääkkeiden yhteisvaikutukset ja yhteensopivuus. Lisäksi teoreettisista taidoista nousi hoitotyön etiikkaan liittyvät tarkkuus ja huolellisuus työssä. Käytännön taidoista tärkeimpinä koulutettavina aiheina kyselystä nousivat asiakkaiden lääkehoidon ja voinnin seuranta, lääkkeiden jakaminen sekä lääkkeiden annosteluun liittyen se, että annostellaan oikeaa lääkettä ja vahvuutta, oikea annos ja oikeaan aikaan sekä oikeat antotavat. Ryhmäkeskusteluista ja lääkärien teemahaastatteluista haettiin syvempää ymmärrystä kyselyn tuloksiin. Yksi tärkeimmistä tämän laadullisen tutkimuksen löydöksistä oli kotihoidon yhteistyöhön liittyvät epäkohdat. Lääkehoitojen toteuttamista ja seurantaa voitaisiin tulosten perusteella parantaa lääkärien ja kotihoidon hoitajien yhteisellä koulutuksella. Tärkeimpiä sairauksia tai oireita, joihin hoitajat toivoisivat yhteisiä toimintakäytäntöjä, ovat diabetes, sydän- ja verisuonisairaudet, kipu, muistisairaudet sekä psyykensairaudet. Lisäksi koulutusaiheiksi tutkimuksesta nousivat iäkkäiden lääkehoidon erityispiirteet, lääkkeiden antoreitit ja lääkemuodot. Kyselyn sekä ryhmäkeskustelujen ja lääkärien teemahaastattelujen tuloksista tehtiin lopuksi synteesi, jonka lopputuloksena LOST-alueen kotihoidon hoitohenkilöstölle sekä kotihoidon lääkäreille koottiin yhteinen tarvelähtöinen täydennyskoulutussuunnitelma. Suunnitelma tehtiin aineistosta nousseiden koulutusaiheiden pohjalta, eikä siihen lisätty aiheita tutkimuksen ulkopuolelta.

Structural, optical and electrical characteristics of transparent bismuth vanadate films deposited on indium tin oxide coated glass substrates

Bismuth vanadate (BVO) thin films were fabricated on indium tin oxide (ITO) coated glass substrates using pulsed laser ablation technique and investigated their structural, optical and electrical properties. The use of the indium tin oxide coated glass substrate resulted in reducing the leakage current characteristics of crystalline BVO thin films. The X-ray diffraction (XRD) studies confirmed the monophasic nature of the post annealed (500 A degrees C/1 h) films. The atomic force microscopy indicated the homogeneous distribution of crystallites in the as-deposited films. The as-deposited and the post annealed films were almost 90% transparent (380-900 nm) as confirmed by optical transmission studies. Dielectric constant of around 52 was attained accompanied by the low dielectric loss of 0.002 at 10 kHz for post annealed films. The leakage current of the post annealed BVO films on ITO coated glass substrates measured at room temperature was 8.1 x 10(-8) A at an applied electric field of 33 kV/cm, which was lower than that of the films with platinum and SrRuO3 as the bottom electrodes.

Bicriterion differential games with qualitative outcomes

Combat games are studied as bicriterion differential games with qualitative outcomes determined by threshold values on the criterion functions. Survival and capture strategies of the players are defined using the notion of security levels. Closest approach survival strategies (CASS) and minimum risk capture strategies (MRCS) are important strategies for the players identified as solutions to four optimization problems involving security levels. These are used, in combination with the preference orderings of the qualitative outcomes by the players, to delineate the win regions and the secured draw and mutual kill regions for the players. It is shown that the secured draw regions and the secured mutual kill regions for the two players are not necessarily the same. Simple illustrative examples are given.

Crystallization characteristics of vitrovac 4040 (Fe39Ni39Mo4Si6B12)

The metallic glass Vitrovac 4040 with the composition Fe39Ni39Mo4Si6B12 crystallizes in the order alpha-Fe, hexagonal Ni5Si2 and gamma-(Fe,Ni,Mo) by primary, secondary and polymorphic modes, respectively. The activation energies determined from the non-isothermal kinetics using Kissinger method turn out to be 490, 550 and 449 kJ.mol-1 for the above crystallization reactions. It has been observed that alpha transforms to gamma during annealing. Further, the bct (Fe1-xNix)3B phase has been identified when the glass is annealed above 1023 K.

Effect of V2O5 on the Surface and Structural Characteristics of Potassium Lithium Niobate

It has been suggested that materials with interesting and useful bulk non-linear optical properties might result by substituting vanadium, the lightest element in the group V of periodic table, for Nb or Ta atoms along with Li and three oxygens. It is with this motivation that we have been making attempts to grow single crystals of LiNbO3 doped with various concentrations of V2O5. Unfortunately the results obtained on the ceramic samples of this material have not been very encouraging, owing to their hygroscopic nature. However, our attempts to prepare both ceramic and single-crystalline samples of potassium lithium niobate (K3Li2Nb5O15; KLN) doped V2O5 were successful. In this letter we report the preliminary results concerning our studies on the effect of V2O5 doping on the structural as well as topographic features of both ceramic and single-crystalline samples of KLN.

Gas Sensing Characteristics of Superconducting Cuprates

Gas sensing characteristics of YBa2Cu3O7−δ, La2−x SrxCuO4, and Bi2Y1−xCaxSr2Cu2O8 have been examined. La2−x SrxCuO4 (x = 0.075), and Bi2YSr2Cu2O8 are found to show good sensitivity (≈10 ppm) to ethyl alcohol and such vapours.

High-frequency capacitance-voltage characteristics of amorphous (undoped)/crystalline silicon heterostructures

A numerical procedure is presented for calculating high-frequency capacitance variation with bias in amorphous (undoped)/crystalline silicon heterojunction. The results of the model calculations using this procedure have been reported, for different p silicon substrates. These have been compared with the corresponding capacitance variations in the other limiting case, in which the heterostructure acts like an MIS structure. The effect of interface states on the capacitance characteristics has also been studied. In the second part, we report the results of 1 MHz capacitance measurements on various amorphous (undoped)/crystalline silicon heterostructures.

Studies on the macroconida of microsporum-canis-characteristics of invitro amino-acid incorporativing system

The characteristics of an in vitro polyuridylic acid dependent amino acid incorporating system prepared from germinating macroconidia of Microsporum canis are described. The incorporation of 14C-phenylalanine into polyphenylalanine is dependent on S-30 extract, adenosine triphosphate, magnesium ions and polyuridylic acid. Incorporation is slightly enhanced by yeast transfer ribonucleic acid and pyruvate kinase. The system is highly sensitive to ribonuclease, puromycin and miconazole (an antifungal agent), moderately sensitive to sodium fluoride and much less sensitive to phenethylalcohol, cycloheximide, chloramphenicol and deoxyribonuclease. Cell-free extract from ungerminated conidia has less capacity to synthesize the protein and during germination a marked increase in the protein synthetic activity is observed. The results from experiments wherein ribosomes and S-100 fraction from germinated and ungerminated spores are interchanged, revealed that the defect in the extract from the ungerminated spore is in the ribosomes.

Complex Permittivity Characteristics of Epoxy Nanocomposites at Low Frequencies

The complex permittivity characteristics of epoxy nanocomposite systems were examined and an attempt has been made to understand the underlying physics governing some of the unique macroscopic dielectric behaviors. The experimental investigations were performed using two different nanocomposite systems with low filler concentrations over the frequency range of 10(-2)-400 Hz, but for some cases, the data has been reported upto 10(6) Hz for a better understanding of the behaviors. Results demonstrate that nanocomposites do possess unique permittivity behaviors as compared to those already known for unfilled polymer and microcomposite systems. The nanocomposite real permittivity and tan delta values are found to be lower than that of unfilled epoxy. In addition, results show that interfacial polarization and charge carrier mobilities are suppressed in epoxy nanocomposite systems. The complex permittivity spectra coupled with the ac conductivity characteristics with respect to frequency was found to be sufficient to identify several of the nanocomposite characteristics like the reduction in permittivity values, reduction in the interfacial polarization mechanisms and the electrical conduction behaviors. Analysis of the results are also performed using electric modulus formalisms and it has been seen that the nanocomposite dielectric behaviors at low frequencies can also be explained clearly using this formalism.

Stress-strain characteristics of Tress-strain characteristics of reinforcing steel bars under cyclic loading

This paper presents test results for 22 high strength deformed bars and nine mild steel bars subjected to monotonic repeated and reversed axial loading to determine the stress-strain behavior. Equations have been proposed for the stress-strain curves and have been compared with test results. Satisfactory agreement was obtained.