ALBERT

Notizen: Many manufacturing firms have increased the amount of component parts and services they outsource, while refocusing on their core capabilities. Outsourcing parts and services to independent, external suppliers means that suppliers' performance is increasingly critical to the long-term success of these buying firms. Buying firms are increasingly using disparate supplier development strategies to improve supplier performance including supplier assessment, providing incentives for improved performance, instigating competition among suppliers, and direct involvement of the buying firm's personnel with suppliers through activities such as training of suppliers' personnel. Using resource-based theory, internalization theory, and structural equation modeling, we examine the impact of these supplier development strategies on performance. We conclude that direct involvement activities, where the buying firm internalizes a significant amount of the supplier development effort, play a critical role in performance improvement.

Notizen: While the concept of partnerships has received much attention in the literature, the focus has primarily been on the manufacturing firm. This paper explores the similarities and differences in partnerships from the perspectives of manufacturing and non-manufacturing firms. Findings indicate that non-manufacturing firms have had longer relationships with their partners than manufacturing firms. In addition, non-manufacturing firms considered a reduction of procurement and administrative costs, in addition to price and reliability, as important reasons to enter partnerships, while manufacturing firms emphasized the price, quality, and delivery of products.

Notizen: Presents results of a survey on supplier development. Surveys were mailed to a random sample of 1,504 NAPM members. The sample was split into two groups depending on how respondents judged the results of their supplier development effort, either exceeding or falling short of expectations. The responses of these two groups to various questionnaire items were investigated to identify and gain insight into factors that contribute to supplier development success. The analysis suggests that buying firm respondents who reported their firms' supplier development efforts to be satisfactory were more likely to have a proactive philosophy regarding suppliers' performance, put more effort and resources into their supplier development efforts, and exhibit a greater willingness to share information with their suppliers than their counterparts who were generally dissatisfied with their firms' supplier development results.

Notizen: Abstract The isotopic fractionation of 3 He/ 4 He has been determined in pure H 2 O, D 2 O, seawater and two alcohols. The measurements have revealed the temperature dependence of the isotopic fractionation in each liquid. Substitution of D 2 O for H 2 O decreases the fractionation by a small but measurable amount. The fractionation varies with salinity and an equation is given for equilibrium values in seawater. The effect in ethanol is approximately 25% less than in water. Interpretation of the experimental results in terms of a zero-point-energy argument suggests that gas molecules dissolved in the different liquids occupy cavities with different sizes. In pure water the cavity size seems to be independent of the solute and is approximately 6 Å.

Notizen: Abstract A very precise and accurate new method is described for determination of the Henry coefficient k and the isotopic fractionation of gases dissolved in liquids. It yields fully corrected values for k at essentially infinite dilution. For oxygen the random error for k is less than 0.02%, which is an order of magnitude better than the best previous measurements on that or any other gas. Extensive tests and comparison with other work indicate that systematic errors probably are negligible and that the accuracy is determined by the precision of the measurements. In the virial correction factor (1+λPt), where Pt is the total pressure of the vapor phase, the coefficient λ for oxygen empirically is a linear decreasing function of the temperature over the range 0–60°C. The simple three-term power series in 1/T proposed by Benson and Krause, $$\ln k = a_0 + a_1 /T + a_2 /T^2 $$ provides a much better form for the variation of k with temperature than any previous expression. With a0=3.71814, a1=5596.17, and a2=−1049668, the precision of fit to it of 37 data points for oxygen from 0–60°C is 0.018% (one standard deviation). The three-term series in 1/T also yields the best fit for the most accurate data on equilibrium constants for other types of systems, which suggests that the function may have broader applications. The oxygen results support the idea that when the function is rewritten as $$\ln k = - (A_1 + A_2 ) + A_1 \left( {\frac{{T_1 }}{T}} \right) + A_2 \left( {\frac{{T_1 }}{T}} \right)^2 $$ it becomes a universal solubility equation in the sense that A2 is common to all gases, with T1 and A1 characteristic of the specific gas. Accurate values are presented for the partial molal thermodynamic function changes for the solution of oxygen in water between the usual standard states for the liquid and vapor phases. These include the change in heat capacity, which varies inversely with the square of the absolute temperature and for which the random error is 0.15%. Analysis of the high-temperature data of Stephan et al., in combination with our values from 0–60°C, shows that for oxygen the fourterm series in 1/T, $$\ln k = - 4.1741 + 1.3104 \times 10^4 /T - 3.4170 \times 10^6 /T^2 + 2.4749 \times 10^8 /T^3 $$ where p=kx and p is the partial pressure in atmospheres of the gas, probably provides the best and easiest way presently available to calculate values for k in the range 100–288°C, but more precise measurements at elevated temperatures are needed. The new method permits direct mass spectrometric comparison of the isotopic ratio34O2/32O2 in the dissolved gas to that in the gas above the solution. The fractionation factor α=32k/34k varies from approximately 1.00085 (±0.00002) at 0°C to 1.00055 (±0.00002) at 60°C. Although the results provide the first quantitative determination of α vs. temperature for oxygen, it is not possible from these data to choose among several functions for the variation ofInα with temperature. If the isotopic fractionation is assumed to be due to a difference in the zero-point energy of the two species of oxygen molecules, the size of the solvent cage is calculated to be approximately 2.5 Å. The isotopic measurements indicate that substitution of a34O2 molecule for a32O2 molecule in solution involves a change in enthalpy with a relatively small change in entropy.

Notizen: Abstract A method for the analysis of precise gas solubility data is presented and applied to new determinations of the Henry constant, k2, for He, Ne, Ar, Kr, and Xe. The values of k2 are fitted to the same sets of temperature functions which we have tried for oxygen. Our previously proposed power series in 1/T, ln(k2/P )=a0+a1/T+a2/T2 (Mark I), gives the best 3-term fit within the temperature range 0–60°C. For use over the full range to the critical temperature of water, we have discovered a new function given by (T*)2ln(k2/P )=A0(T*)2+A1(1-T*)1/3+A2(1-T*)2/3(Mark II), where T*≡T/T c1 . It fits our data from 0–60°C nearly as well as Mark I; it fits high temperature data from other sources; and at the critical temperature of water it satisfies theoretical requirements. Expansion of Mark II reveals the relationship between Mark II and Mark I and leads to a 4-term smoothing function, ln(k2/P )=a−2(T*)−2+a−1(T*)−1+a0+a1T* (Mark III), which we believe gives the best values only for the 0–60°C range. Mark III is used to calculate values for $$\Delta \bar G^\theta ,\Delta \bar H^\theta ,\Delta \bar S^\theta $$ , and $$\Delta \bar C^\theta $$ , 0–60°C, and a procedure is empolyed to estimate the errors. Agreement is excellent between these results and those obtained from precise microcalorimetric measurements made by others. With the inclusion of pressure correction terms, Mark II yields the four thermodynamic function changes for use at high temperatures. With increasing temperature, these changes suddenly turn upward toward plus infinity as T c1 is approached. Essentially direct determinations of $$\Delta \bar C^\theta $$ for argon by other workers are in excellent agreement with our results. The symmetrical activity coefficient at infinite dilution, γ 2 ° is examined and the hypothetical properties of k2 are explored below 0°C. Mark II can be expressed in the reduced form (T*)2ln(k 2 * )=A1(1-T*)1/3+A2(1-T*)2/3, where k 2 * ≋k 2/(p c1φ2c1). A2 is a very good linear fit to A1, which suggests a characteristic temperature for water at 287.3 K.

Notizen: Abstract A rigorous, compact, somewhat unconventional, thermodynamic analysis is presented for the treatment of very precise data on the solubilities of gases in liquids. Relationships among the chemical potentials, fugacities, fugacity coefficients, activity coefficients, molar volumes, and mole fractions, and the standard states involved, are carefully delineated. Both the symmetrical and asymmetrical choices for the activity coefficients are discussed, together with the connections between them. The symmetrical activity coefficient at infinite dilution, γ 2 ° (T,p), is shown to be a very useful parameter for generalizing the ideal solubility concept of Hildebrand and Scott, and to be the factor which links corresponding concepts in the symmetrical and asymmetrical standard states. Arguments are presented for adopting $$\mathop {\lim }\limits_{{\text{as }}x_2 \to 0} {\text{ [}}f_2^{\text{L}} (T,p,x_2 )/x_2 {\text{] = }}k_2 (T,p)$$ where k2 is the Henry constant as the statement of Henry's law. The measured ratio,f 2 V /x 2, is given the name Henry function and denoted by F H2 . The Krichevsky-Kasarnovsky equation can be generalized to $$F_{{\text{H2}}} (T,p,x_2 ) = k_2 (T.p_{\sigma 1} )[\gamma '_2 (T,p,x_2 )]{\text{ exp }}\mathop \smallint \nolimits_{p_{\sigma 1} }^p [\nu _2^{ - {\text{o}}} (T,p')/RT]{\text{d}}p'$$ which is the basis for the determination of very precise values for k2(T,pσ1). Several hypothetical functional representations for the activity coefficient are used in conjunction with the ideas above, to explore the implications of the very non-ideal character of dilute aqueous solutions of gases. Exact expressions are derived for the differences in partial molar Gibbs free energy, enthalpy, entropy, and heat capacity at constant pressure, of the solute gas between the hypothetical liquid standard state and the ideal gas state. Corrections for the temperature variation of pσ1 are included.