Search results for "efficien"

1990

Intrinsic viscosities, [η], second virial coefficients, A2, and interaction potentials, g12, for the ternary systems alcohol (1)/3-heptanone (2)/poly(1-vinyl-2-pyrrolidone) (3), with the unbranched alcohols methanol, ethanol and 1-propanol, were determined at 25°C. Taking into account the dependence of the viscometric interaction parameter, B, with the molecular weight of the polymer, the unperturbed dimensions parameter, KΘ, of the polymer was unambiguously obtained. Relationships between ΔKΘ (defined as ΔKΘ = ΔK − KΘ) and excess Gibbs energies, GE, and between excess viscosity, Δ[η], and GE allow to obtain equations relating A2 to ΔKΘ or to Δ[η]. Therefore, A2 can be evaluated from experi…

Bestimmung der molekularen konstanten von naturkautschuk III. Molekulargewicht trägheitsradius und thermodynamische eigenschaften von cyclohexan-kaut…

1960

Lichtstreuungsmessungen an Crepekautschuk in Cyclohexan ergeben Mw = 1,85·106. In Verbindung mit Diffusions- und Sedimentationsmessungen ergibt sich als wahrscheinlichster Wert Mw = 1,7·10−6. Unter Verwendung der Messungen von CARTER, SCOTT und MAGAT wird als Molekulargewichts-Viskositatsbeziehung die Gleichung fur Losungen von Naturkautschuk in Cyclohexan vorgeschlagen. Der 2. Virialkoeffizient und der STAUDINGER-Index nehmen in der Reihenfolge Benzol, Cyclohexen, Cyclohexan zu. Die beiden ersten Losungsmittel sind endotherm, Cyclohexan ist exotherm. Der Tragheitsradius der Molekulknael nach Lichtstreuungsmessungen ist etwa Rw = 1000 A. Der wahrscheinlichste Wert unter Mitberucksichtigung …

The initial stages of the heterogeneous degradation of alkali cellulose by oxygen in relation to the morphology of native cotton cellulose

2007

Treatment of cotton cellulose with sodium hydroxide solutions of varying concentration over extended periods in the absence of oxygen markedly decreases the intrinsic viscosity of both the cellulose in cuoxam and its cellulose trinitrate derivative (CTN) in acetone. Light-scattering measurements show that the molecular weight does not change while the radius of gyration decreases and the second virial coefficient increases. The narrow molecular weight distribution of the native cotton is still maintained. Mild oxidation first causes the intrinsic viscosity to increase. At more prolonged oxidation times the viscosity decreases. These results are interpreted by an intramolecular cross-linking…

Thermodynamisches verhalten, expansionskoeffizient und viskositätszahl von polystyrol in tetrahydrofuran

1968

Streulichtmessungen ergeben, das Polystyrollosungen in Tetrahydrofaran stark exothermisch sind; der 2. Virialkoeffizient des osmotischen Druckes A2 wird uberwiegend durch den Enthalpieterm A2,H bestimmt. Der Expansionskoeffizient gehorcht der (α5−α3)-Beziehung mit der Konstante von STOCKMAYER und die h(z)-Funktion der Gleichung von CASASSA. Die Viskositatszahl [η] wird durch die Gleichung von KURATA und YAMAKAWA erfast. Mit den drei Parametern β/M, K0 = r/M und b/M (b = hydrodynamischer Durchmesser) lassen sich A2, α, [η] und der Tragheitsradius r uber einen grosen Molekulargewichts-bereich in guter Ubereinstimmung mit den Meswerten berechnen (vgl. Abb. 3). Light scattering measurements of …

Solubilità, proprietà acido - base e coefficienti di attività del chitosano in soluzione acquosa a 298.15°K

2008

The detection efficiency of the clover Ge-detectors array at the RITU-GREAT facility

2015

Absolute detection efficiency depending upon its position along the beam line is determined for three germanium detectors, that are part of the GREAT spectrometer at the RITU separator focal plane. The efficiency is determined for an energy range from 80 keV to 1400 keV for all three detectors as an array and also individually using digital electronics. The optimal position for the detector array has been defined for two configurations of the GREAT spectrometer: with planar detector and without it. The obtained results have been compared with three references: a simulation prepared especially for this setup by another student, a previous study that was carried out by applying analogue elect…

Efficiency of Hospital Expenses Projects Funded Through Partnership with an NGO Case Study

2017

In the context of limited resources of a public hospital, constrained by rigid regulations and lowcapacity to invest in the purpose of satisfying the raising needs of the patients, the health facilityembraced the solutions to partner with an NGO. In partnership with Association of Psychiatric Hospital Dr. Gheorghe Preda Sibiu (ASPPS) alarge number of projects have been developed. The projects aimed to create new means andmethods for complementary and ocupational therapy and to ensure a friendly and suportiveenvironement for the patients. With rather modest financial resources but maximum eficiency and voluntary work, manymodern facilities were created, some even in premiere.

Validation and Measurement Invariance of the Scale of Positive and Negative Experience (SPANE) in a Spanish General Sample

2020

Este artículo se encuentra disponible en la siguiente URL: https://www.mdpi.com/1660-4601/17/22/8359 Este artículo pertenece a la sección "Health behavior, chronic disease and health promotion". Well-being has been measured based on di erent perspectives in positive psychology. However, it is necessary to measure a ects and emotions correctly and to explore the independence of positive and negative a ect. This cross-sectional study adapts and validates the Scale of Positive and Negative Experience (SPANE) with a non-probabilistic sample of 821 Spanish adults. A confirmatory factor analysis confirmed two related factors with two correlated errors. The average variance extracted was 0.502 for…

The Acceptable Alternative Vehicle Fuel Price

2019

Historically, petroleum fuels have been the dominant fuel used for land transport. However, the growing need for sustainable national economics has urged us to incorporate more economical and ecological alternative vehicle fuels. The advantages and disadvantages of them complicate the decision-making process and compel us to develop adequate mathematical methods. Alternative fuel (compressed natural gas, liquefied petroleum gas, and ethanol fuel mixtures), the standard prices and their ratios were investigated. A mathematical model to determine a critical ratio between alternative and conventional fuel prices had already been developed. The results of this were investigated. The results sho…

On the synthesis of functionalized porphyrins and porphyrin conjugates via β-aminoporphyrins

2016

International audience; The synthesis of functionalized porphyrins and their conjugates from meso-tetraarylporphyrins through the acylation and the oxidation of beta-aminoporphyrins was investigated. 2,3-Dioxochlorins were prepared by the oxidation of a variety of beta-aminoporphyrins and subsequently used in a condensation reaction with functionalized aromatic aldehydes and ammonium acetate to form beta-functionalized porphyrins bearing a fused imidazole ring. Under optimized experimental conditions both reactions tolerate various functional groups and afford the products in an appropriate overall yield. The mildness and usefulness of this methodology are illustrated by several examples in…