The 'hydrophobic effect' of the dissolution process of non-polar substances in water has been analysed under the light of
a statistical thermodynamic molecular model. The model, based on the distinction between non-reacting and reacting systems explains the changes of the thermodynamic functions with temperature in aqueous systems. In the dissolution of non-polar
substances in water, it follows from the model that the enthalpy change can be expressed as a linear function of the temperature
(ΔHapp =ΔHø +nwCp,wT ). Experimental solubility and calorimetric data of a large number of non-polar substances nicely agree with the expected
function. The specific contribution of nw solvent molecules depends on the size of solute and is related to destructuring (nw >0) of water molecules around the solute. Then the study of 'hydrophobic effect' has been extended to the protein denaturation
and micelle formation. Denaturation enthalpy either obtained by van't Hoff equation or by calorimetric determinations again
depends linearly upon denaturation temperature, with denaturation enthalpy, ΔHden , increasing with T . A portion of reaction enthalpy is absorbed by a number nw of water molecules (nw >0) relaxed in space around the denatured moieties. In micellization, an opposite process takes place with negative number
of restructured water molecules (nw <0) because the hydrophobic moieties of the molecules joined by hydrophobic affinity occupy a smaller cavity.
Study of the gypsum-hemihydrate-soluble anhydrite transitions by thermal, X-ray and IR methods showed differences in the intensity
of the ∼3493 cm−1 IR absorption peak of the gypsum samples and differences in the peak ratios of the DTA curve at the gypsum-hemihydrate transition.
There were also differences in the temperature and rate of the γ−β anhydrite transition. This suggests that different gypsum
species occur, specially among synthetic gypsum.
Fifteen equations were tested in order to find models which fitted the gypsum-hemihydrate and the hemihydrate-anhydrite transitions.
No model fitted all the samples. The best fit for the gypsum-hemihydrate transition in three samples was an order of reaction
equation while for the hemihydrate-anhydrite transition the best fit in four samples was a power law. Differences in crystallite
characteristics appear to be one of the main reasons for the differences in kinetics between the samples.
Assuming that the correlation between the cocrystallization coefficients and solubilities of the co-crystallizing ethylsulphates in the [(Ln,M) (H2O)9] (C2H5SO4)3–H2O system is valid when M is changed from lanthanides into the title elements, the solubilities of the ethylsulphates of trivalent Y, Pm, Pu, Am and Cm in water at 288–318 K have been determined from the matrix. The solubilities of Y, Pm, Pu, Am and Cm ethylsulphates and of all the lanthanide ethylsulphates are given in the form of smoothing equations of the lg molality=A+B/T type. From the B parameters of the solubility equations the enthalpies of solution have been estimated. The crystallization behaviour of yttrium in the ethylsulphate system is between that of holmium and that of erbium.
Az újonnan kidolgozott forróvizes extrakciós módszerrel (HWP) nyerhető foszfor és kálium vizsgálati eredmények értelmezése érdekében összehasonlító vizsgálatot végeztünk a Magyarországon hivatalos AL módszerrel. A zömében tartamkísérletekből, valamint üzemi táblákból származó 315 talajmintán hasonlítottuk össze a két módszerrel kioldott foszfor- és káliumtartalmakat. Mind a foszfor, mind a kálium esetében a két módszerrel nyert eredmények szoros összefüggésben voltak egymással, de az összefüggések szorosságát a talajok fizikai és kémiai tulajdonságai befolyásolják. A nagy abszolút értékbeli különbségek (átlagosan 10–20-szor nagyobb értékeket ad az AL módszer) ellenére a két módszerrel nyert eredmények – vizsgálati helyenként – a fentiek figyelembe vételével átkonvertálhatók egymásba. További előrelépést jelenthet a két módszer átjárhatóságában, ha még nagyobb számú mintán a foszfor esetében a kalcium-karbonát jelenléte, esetleg a kötöttség, kálium esetében pedig a kötöttség figyelembevételével végezzük el az átszámítást. A vízoldható elemtartalomnak ugyanis – különösen környezetvédelmi szempontból – kiemelt jelentősége van.
The solid solubility of the 3d metals Cr, Mn, Fe, Co and Ni in high-purity silicon was studied by INAA and electron paramagnetic
resonance techniques in the temperature range of ≊600°C–1250°C. The solubility increases with atomic number from Cr to Mn
and more distinctly from Co to Ni. For Mn, Fe and Co the solubilities are nearly the same within the experimental errors.
An enthalpy of formation (ΔH) of about 2.8 eV was determined for Cr, Mn, Fe and Co, whereas for Ni 1.7 eV was derived. Relatively
large diffusion coefficients were estimated from the rather short times, in which saturation of the solid solution was reached.
From these observations and from the results of the EPR measurements it is concluded that the 3d metals occupy predominantly
interstitial sites in the silicon lattice in thermal equilibrium.
Authors:B. Smith, R. Gibson, G. Jarvinen, M. Jones, M. Lu, T. Robison, N. Schroeder, and N. Stalnaker
Water-soluble metal-binding polymers in combination with ultrafiltration are shown to be an effective method for selectively
removing dilute actimide ions from acidic solutions of high ionic strength. The actinide-binding properties of commercially
available water-soluble polymers and several polymers which have been reported in the literature were evaluated. The functional
groups incorporated in the polymers were pyrrolidone, amine, oxime, and carboxylic, phosphonic, or sulfonic acid. The polymer
containing phosphonic acid groups gave the best results with high distribution coefficients and concentration factors for241Am(III) and238Pu(III)/(IV) at pH 4 to 6 and ionic strengths of 0.1 to 4.
Authors:B. Smith, R. Gibson, G. Jarvinen, T. Robison, N. Schroeder, and N. Stalnaker
A preconcentration approach to assist in the measurement of low levels of americium and plutonium in waste waters has been
developed based on the concept of using water-soluble metal-binding polymers in combination with ultrafiltration. The method
has been optimized to give over 90% recovery and accountability from actual waste water.
Lycopene content (LC) and soluble solid content (SSC) are important quality indicators for cherry tomatoes. This study attempted simultaneous analysis of inner quality of cherry tomato by Electronic nose (E-nose) using multivariate analysis. E-nose was used for data acquisition, the response signals were regressed by multiple linear regression (MLR) and partial least square regression (PLS) to build predictive models. The performances of the predictive models were tested according to root mean square and correlation coefficient (R2) in the training set and prediction set. The results showed that MLR models were superior to PLS model, with higher value of R2 and lower values of for RMSE firmness, pH, SSC, and LC. Together with MLR, E-nose could be used to obtain firmness, pH, soluble solid and lycopene contents in cherry tomatoes.
Authors:M. Rakszegi, G. Balázs, F. Békés, A. Harasztos, A. Kovács, L. Láng, Z. Bedő, and S. Tömösközi
Damaged starch, protein and arabinoxylan (AX) content and composition have been related to water absorption (WA) in a large set of samples. We tested 20 modern bread wheat cultivars bred in Hungary, 20 old Hungarian landraces, and 17 cultivars with special biochemical/functional characteristics from all around the world, this last set for international comparison. Grain was field grown in the 2011 and 2012 harvest seasons. Alinear mathematical model has been developed to estimate WA from protein content, starch damage, AX content and the relative amount of soluble proteins with strong correlation (r2 = 0.65) between measured and estimated data. The introduction of a new parameter, related to the cultivar dependent quantitative composition of soluble proteins and determined by lab-on-a-chip (LOC) analysis, largely improved the predictability of WA. Based on the large variation among the level of AX and certain soluble protein components in wheat flour and their significant contribution toWA determination, it was concluded, that these properties could be appropriate target traits to alter them during wheat breeding programs to improve the WA of wheat flour.
The recoid feature of central metal atoms in the bi-component solid system of water-soluble metalloporphyrin ion associates
was investigated in bremsstrahlung and thermal neutron irradiation at very low temperatures. Very preferable substitution
of stable Zn central metal atoms by the Cu* recoil was observed in the system of [M(TMPyP)][M′(TCPP)] (M,M′=Cu, Zn) in both irradiations, while no such tendency was
seen in the system of [M(TMPyP)][M′(TPPS)] (M,M′=Cu, Zn). The predominant factor for the difference of the recoil feature
is discussed. (H2TMPyP: tetrakis(4-N-methylpyridyl)-porphine, H2TCPP: tetra(p-carboxyphenyl)porphine, H2TPPS: tetra(p-sulfophenyl)-porphine).