New measurements have been made for the viscosity (η) of light and heavy water between the temperatures of 255.65 K and 298.15 K at pressures up to approximately 375 MPa with a falling-body viscometer. A revised correlation function is used to represent the results as a function of temperature and molar volume (V) with a standard deviation of ±0.2% for both H2O and D2O. The overall uncertainty is estimated at ±1%. Comparison of the two sets of data shows that they are consistent with the correlation η(D2O,T,V) = 1.0544η(H2O,T − 6.498 K,V) where 1.0544 is the square root of ratio the molar masses and 6.498 K is the thermal offset proposed by Robinson and co-workers.

Fluids of larger polyatomic molecules do not well fit the hard sphere model of dense fluids as their liquid range, reduced in terms of relative molecular volumes, usually extends well beyond the freezing density of the hard sphere fluid. Even where overlap occurs, the density dependence is observed to be not as simple as that of the model. It is for this reason that empirical functions for the density dependence of the transport properties have been developed. Application of such correlations has thrown some doubt on previous high-pressure measurements of the viscosity of liquid octane and toluene. New measurements have been made for octane between 283 K and 348 K and for toluene at 298 K and 323 K at pressures up to approximately 375 MPa with a falling-body viscometer. These are supplemented by pVT measurements for octane between 278 K and 298 K, which have been used to improve an earlier equation of state. The viscosity results are compared with earlier data using a general correlation method for molecular liquids.

This article explores the experiences of customers who receive service in relationships (customers who return to the same provider for service), pseudorelationships (the same organization but a different provider), and encounters (neither a regular provider nor a regular firm). We examined interactions with hairstylists, auto mechanics, and physicians to test hypotheses about customers' reactions to service delivery. Although customers respond particularly well to service relationships, based on our results for auto mechanics, it appears possible for firms to design pseudorelationships that also are relatively high in trust.

The effect of pressure on the volume of aqueous solutions of 2-methyl-2-propanol (t-butyl alcohol) has been measured as the ratio of the volume under pressure to its value at 0.1 MPa with a bellows volumometer for temperatures from 5 to 75 degrees C at pressures up to 300 MPa. Six compositions have been used covering the mole fraction range from 0.025 to 0.45 as well as pure 2-methyl-2-propanol. Isothermal compressibilities and thermal expansivities have been calculated from the results. Significant features in those properties are discussed. The data have also been fitted to Hayward and Tait equations of state.

A two-stage model has been used successfully to predict the drying curves for d'Agen prunes. The model assumes the drying process occurs in two distinct stages. First, a period where the evaporation of water from the surface of the drying fruit is the limiting factor for the moisture loss is assumed. This results in a constant rate of water loss. A second period of drying occurs when a water concentration gradient has been established within the plum. During this time, the rate of moisture loss is limited by the mass transfer of water through the fruit, leading to a falling rate of evaporation of water at the fruit surface. This model predicts reasonable values for the moisture loss as a function of drying time. Significant discrepancies between the experimental results and the model occur only for a longer drying time at the higher temperature range (e.g. 90 degrees C and above). This is due mainly to uncertainty in the value for the equilibrium moisture loss caused by other weight loss processes in the latter stages of drying such as thermal degradation of carbohydrates. (C) 1997 Elsevier Science Ltd.

The effect of pressure on the volume in the liquid phase for chlorobenzene and 1,2-dichlorobenzene has been measured relative to their volumes at 0.1 MPa with a bellows volumometer for pressures up to 300 MPa over the temperature range (278.15 to 338.13) K. The experimental volume ratios have been represented by two sets of equations to enable interpolation and extrapolation of volumetric properties. The results of one of these representations suggests a means of extrapolating the volumetric properties of these chloro-substituted benzene derivatives. Isothermal compressibilities, thermal expansivities, normalized volume fluctuations, and the change in the isobaric heat capacity from its value at 0.1 MPa have been calculated from the results.

Dehydration is an energy intensive operation widely used in the Agro-Food industry This al the kinetics of drying of d'Agen plums (Prunus domestica). The effect of operating parameters on the rate of moisture loss is examined and from the results a physico-chemical model is developed which gives insight into the changes during dehydration in particular compositional changes of the carbohydrates present, were studied. The kinetics of the chemical reactions taking place, the role of fruit pH and the implications for final fruit quality are discussed.

The effect of pressure on the volume in the liquid phase for two ethyl alkanoic acid esters, the propionate and butyrate, has been measured relative to the volume at 0.1 MPa with a bellows volumometer for pressures up to 380 MPa over the temperature range (278.15 to 338.13) K. The experimental volume ratios have been represented by two sets of equations to enable interpolation and extrapolation of volumetric properties. One set enables intercomparison of the volume ratios for the two esters and with literature data for ethyl acetate. The comparison permits volumetric data for all three liquids to be generated with reasonable accuracy from those for ethyl propionate by making an allowance for the number of -CH2 groups in the alkanoic acid segment of the ester. A. small modification of the predictive method enables calculation, with lesser accuracy, of volumetric data for methyl, propyl, and butyl acetates. Isothermal compressibilities, isobaric expansivities, and the change in the isobaric heat capacity from its value at 0.1 MPa have been calculated for both esters from the volumetric data.

The effect of pressure on the volume in the liquid phase for three acetates, propyl, butyl, and 1-methylethyl (isopropyl), has been measured relative to the volume at 0.1 MPa with a bellows volumometer for pressures up to 380 MPa over the temperature range (278.15 to 338.13) K. Densities of the liquids at 0.1 MPa have been determined for the same temperatures. The experimental volume ratios have been represented by two sets of equations to enable interpolation and extrapolation of volumetric properties. One set enables intercomparison of the volume ratios for the three acetates and with literature data for methyl and ethyl acetates. The comparison permits volumetric data for all five liquids to be generated with reasonable accuracy from those for propyl acetate by making an allowance for the number of _CH2 groups in the alkyl part of the acetate; the prediction is least accurate for methyl acetate and 1-methylethyl acetate. Isothermal compressibilities, isobaric expansivities, and the change in the isobaric heat capacity from its value at 0.1 MPa have been calculated from the volumetric data.

The kinetics of the drying of prunes (Prunus domestica) have been investigated as a function of temperature (70–100 °C). The variety of plum used was D'Agen. The prunes were dried in an oven under exhaust conditions resulting in a constant relative humidity during drying (70–80%). It was found that simple first-order kinetics fitted the experimental data well. This is consistent with a diffusion-controlled process through the fruit matrix. The activation energy plot was found to be non-linear with a much higher activation (80 kj mol−1) at the lower temperature end. This indicates a more hindered path for diffusion of the water through the matrix. This is consistent with what is known about the temperature dependence of cell rupture and disturbance of structure in such a material. In addition, estimates of diffusion of water through the food matrix are much slower than the self-diffusion coefficient of water across the entire temperature range. This also emphasises the hindered nature of the process.

A bellows volumometer has been used to obtain volume ratios relative top= 0.1 MPa for each of the liquids pentan-2-one, hexan-2-one, and 4-methylpentan-2-one at the temperatures (278.15, 288.15, 298.14, 313.14, 323.14, and 338.13) K for pressures up to 386 MPa or close to the freezing pressure, which ever is the lower. A correlation which uses a modification of the Tait equation predicts that the volumetric properties of the present compounds are usually close to the experimental error. The correlation is based on a modified Tait equation for butan-2-one which has been generalised by including an allowance for each methylene group added to produce higher order ketone. The correlation is not as successful for propanone or pentan-3-one. The experimental volumetric data have been used to evaluate the effects of pressure on isothermal compressibility, isobaric thermal expansivity, and isobaric heat capacity.

Interactions between ions have a very significant effect on the properties of electrolytes, This paper discusses two approaches to the study of interactions in electrolyte solutions using experimental transport coefficients. One is based on generating generalized transport coefficients from experimental data. A number of variants have appeared in the literature, the preferred ones, distinct diffusion coefficients, as formulated by Friedman are used here. Their usefulness and interpretation in terms of ionic interactions are discussed. One limitation of the above is that they are based on solvent-averaged potentials, The other approach deals with our attempts to use the water diffusion coefficient and shear viscosity data to gain insights into ion-solvent interactions and into hydration dynamics of muitivalent cations.

The effect of pressure on the volume of liquid 1,2-dichloro-1,2,2-trifluoroethane (R123a) has been measured relative to the volume at 0.1 MPa with a bellows volumometer for pressures up to 380 MPa over the temperature range (278.15 to 298.14) K and up to about 275 MPa for (313.14 to 338.13) K. The experimental volume ratios have been represented by equations to enable interpolation and extrapolation of volumetric properties. Isothermal compressibilities, isobaric expansivities, internal pressures, and the change in isobaric heat capacity from its value at 0.1 MPa have been calculated. Although there are similarities between these properties and those of 2,2-dichloro-1,1,1-trifluoroethane (R123), there are differences, indicating the effects of the greater asymmetry of the molecular structure of R123a.

BACUP is a cancer charity which has been providing information, counselling and support for 10 years. The Cancer Information Service has responded to over 200,000 requests for information and support. Analysis of our data reveals changing trends in who asks for information and what they ask for. Factors such as age, gender and social class affect how people access and use the services BACUP provides. Nurses playa crucial role in the direct provision of information and also in referring people to other agencies which can help them. Our experience raises questions about differences in information seeking behaviours which are important for nurses to incorporate into their daily work supporting cancer patients and their families. BACUP is a cancer charity which has been providing information, counselling and support for 10 years. The Cancer Information Service has responded to over 200,000 requests for information and support. Analysis of our data reveals changing trends in who asks for information and what they ask for. Factors such as age, gender and social class affect how people access and use the services BACUP provides. Nurses playa crucial role in the direct provision of information and also in referring people to other agencies which can help them. Our experience raises questions about differences in information seeking behaviours which are important for nurses to incorporate into their daily work supporting cancer patients and their families.

An automated bellows volumometer has been used to obtain volume ratios for 2,2,2-trifluoroethyl difluoromethyl ether (CHF2OCH2CF3, RE245) and 1,2,2,2,-tetrafluoroethyl-difluoromethyl ether (CHF2OCHFCF3, RE236) for pressures up to 380 MPa in the temperature range (278.15 to 338.13) K in the liquid phase. The fractional accuracy of the volume ratios is estimated to be ± (0.0005 to 0.001) for the experimental temperatures up to the normal boiling temperature of both fluids and better than ±0.0015 for higher temperatures. Isothermal compressibilities, isobaric expansivities, and internal pressures have been evaluated from the volumetric results. The volume ratios have been represented by Tait equations which enable accurate predictions of liquid densities along the (liquid + vapour) coexistence boundary. The experimental values for both liquids over the complete range of experimental temperatures can be combined by modifying the Tait equation representing the volumetric properties of CHF2OCH2CF, to allow for the contribution of the additional fluorine atom to the volumetric properties of CHF2OCHFCF3. The modified equation appears to be suitable for predicting the volumetric properties of other linear fluoroethers with a molecular composition based on three carbon atoms.

In a recent publication, Mills et al. (1) calculated distinct diffusion coefficients in 4 frames of reference for 14 binary nonelectrolyte mixtures. Because of space limitations, some of the data were represented graphically in that paper. The distinct diffusion coefficient data for the mass-, volume- and number-fixed frames of reference for all systems are given numerically here. The thermodynamic factor (partial derivative ln a(i)lpartial derivative ln x(i))T,P, which is often used in mass-transport theories, is also given.

Excess thermodynamic quantities have been calculated from volumetric data for liquid mixtures of 1,2-dichloroethane (DCE) with 2,2,4-trimethylpentane (TMP) over the temperature range 278.15 to 338.15 K for pressures up to the lower of either near the freezing pressure of DCE or 280 MPa. There are indications that pressure- or temperature-induced variations in the relative proportions of the trans and gauche forms of DCE affect the excess properties of the mixtures.

Generalized transport coefficients are indispensable for the study of interactions between species of the same kind in binary solutions. Distinct diffusion coefficients are best suited for this purpose because of their finite limiting values and inherent symmetry. Equations are derived for the calculation of these coefficients from experimental data for the mass-, volume-, number-, and solvent-fixed frames of reference. Distinct diffusion coefficients in the 4 reference frames computed for 14 binary nonelectrolyte solutions show that the number-fixed frame is probably best suited for the comparison of the macroscopic properties of these solutions. A point of contention has been the frame of reference of the Friedman-Milis equation;(1) surprisingly, the mass-fixed frame describes its D-ij(d) values closely.

An automated bellows volumometer (Malhotra and Woolf, 1993a) has been used to obtain pVT data for 1,1-dichloro-1-fluoroethane in the form of volume ratios for pressures up to 380 MPa in the temperature range 278.15 to 338.15 K in the liquid phase. The accuracy of the volume ratios is estimated to be ±0.05 to 0.1% for the experimental temperatures up to 298.15 K and better than ±0.15% for temperatures above the normal boiling point of R141b. The volume ratios enable accurate predictions of liquid densities along the liquid-vapour coexistence boundary. Isothermal compressibilities, isobaric expansivities, internal pressures and isobaric molar heat capacities have been evaluated from the volumetric data.

Selfdiffusion coefficients determined by the NMR spin-echo technique are reported for n-octane (-25–75°C, 0·1–361 MPa) and toluene (-50–50°C, 0·1–369 MPa). In the case of toluene, these are supplemented at 25°C by 14C radiotracer diaphragm cell measurements. The results for each substance are correlated with high pressure viscosity data. Those for toluene overlap the range of applicability of the rough hard sphere model, and this model is used to compare the transport properties of toluene with those of benzene and mesitylene.