Lost Directions: U.S. Foreign Assistance Policy Since New Directions

International Development,

New chelating reagents for the separation of metal complexes by high performance liquid chromatography

New chelating reagents for the complexation of metal ions in aqueous samples, have been developed. The reagents synthesized and tested were 2,6-diacetylpyridine bis(N-methylenepyridiniohydrazone) dichloride (abbreviated H[subscript]2dapmp), 2,6-diacetylpyridine bis(N-methylene-N,N,N-trimethylammonio-hydrazone) dichloride (abbreviated H[subscript]2dapmta), and 2-acetylpyridine-4-ethyl-3-thiosemicarbazone (abbreviated Hapet). All three chelating reagents proved to be useful for the separation and determination of metal ions by reverse-phase high performance liquid chromatography. Both H[subscript]2dapmp and H[subscript]2dapmta formed kinetically stable metal complexes that did not dissociate on the chromatographic column;H[subscript]2dapmp and H[subscript]2dapmta were prepared and characterized. Both complexing reagents contained quaternary ammonium groups which greatly enhanced the water solubility of the reagents and their metal-ion complexes. When the solid H[subscript]2dapmp was dissolved in water, an equilibrium was attained in which three geometric forms co-exist. A rate constant was determined for the equilibrium of the E,E isomer, into the E,Z and Z,Z geometrical isomers. Several metal ions, including Ti(IV), Fe(III), V(V), and U(VI), were determined quantitatively and selectively by complexation with one of the bis hydrazones and chromatographic separation of the metal ion complexes at pH 3.3;At a pH of 7 it was possible to extend the technique and separate and determine 8 metal complexes, in a single run, under gradient conditions on a polystyrene-divinylbenzene polymer based column. Possible separation of rare earth complexes and ion-pairing behavior were also investigated. Linear calibration curve ranges and detection limits are presented for the metal complexes of Sn(II), Ti(IV), Mn(II), Co(II), Cd(II), Sb(III), Cu(II), Ni(II), Pr(III) and U(VI) under neutral conditions. Interferences due to the presence of other metal ions in solution were also investigated at both pH values;Hapet was prepared and extensively characterized. Hapet complexes of In(III), Ga(III), Fe(III), Co(II), Zn(II), Cd(II), Bi(III), and Pd(II) were separated chromatographically using reverse-phase HPLC. Many of these metal ions were also tested for linear calibration ranges, and the effect of foreign ions in the sample solution. The effects of varying chromatographic conditions on metal complex retention are also described

Optimization of the material selection process for cryogenic composite overwrapped pressure vessels

The objective of this research was to develop a test methodology for the evaluation of materials for possible use in cryogenic composite overwrapped pressure vessels (COPVs). This paper investigates various micromechanical and macromechanical techniques to test the interaction between fibers and resins. Uniaxial tension testing was performed at ambient and cryogenic temperatures on neat resin samples, straight-sided composite specimens, and NOL ring specimens. COPVs were constructed and burst tested to provide a performance comparison. Results show resins suitable for use at cryogenic conditions display a LN2 temperature elongation to failure greater than 2% and an ambient temperature elastic modulus less than 35 MPa. NOL rings were determined to be the preferred composite test method rather than straight-sided specimens. Mechanical performance of the NOL rings compares well with actual COPV performance

Optimization of the material selection process for cryogenic composite overwrapped pressure vessels

The objective of this research was to develop a test methodology for the evaluation of materials for possible use in cryogenic composite overwrapped pressure vessels (COPVs). This paper investigates various micromechanical and macromechanical techniques to test the interaction between fibers and resins. Uniaxial tension testing was performed at ambient and cryogenic temperatures on neat resin samples, straight-sided composite specimens, and NOL ring specimens. COPVs were constructed and burst tested to provide a performance comparison. Results show resins suitable for use at cryogenic conditions display a LN2 temperature elongation to failure greater than 2% and an ambient temperature elastic modulus less than 35 MPa. NOL rings were determined to be the preferred composite test method rather than straight-sided specimens. Mechanical performance of the NOL rings compares well with actual COPV performance

Wage inequality and productivity growth:motivating sticks and crippling carrots

Wage inequality is a particular focus of attention not only in public debates over the need for social regulation to support equity, but those over the implications of social regulation for productive performance. The present paper employs panel techniques to examine the comparative historical relationship between wage inequality and hourly labour productivity growth in the manufacturing sectors of nine advanced industrialised nations over the period 1970-1995. The results show that whilst greater inequality in the top half of the wage distribution is associated with greater productivity growth, greater inequality in the bottom half is associated with lower productivity growth. It appears that whilst wage inequality in the top half of the distribution productively motivates higher earners, wage inequality in the bottom half of the distribution is detrimental for productivity performance. The latter result is most likely attributable to the weak incentives to reorganise production where extremely low pay is feasible

Work humanization : comparative historical developments in the manufacturing sectors of advanced capitalist societies, 1960-1995

The thesis draws on official statistics to examine comparative historical developments in the humanization of work in manufacturing industry, engaging with vital debates on societal distinctiveness. The empirical analysis spans the manufacturing sectors of eleven of the leading industrialised nations over the period 1960-95. This substantive core of the thesis is informed by an examination of research method in the field of employment relations. Initial assessment of the availability and construct validity to aggregate statistical indicators of the humanization of work results in consideration of three phenomena; the rate of incidence of fatal injuries, average annual hours actually worked, and the relative extent of managerial hierarchy. Detailed assessment of the conceptual basis of the available statistics then follows, with the aim of obtaining historically consistent and cross-nationally comparable data on these aspects of work humanization. Although dependable data on fatalities and hours are derived, the limits of the aggregate indicator of managerial hierarchy are ultimately stressed. The comparative historical patterns in the data are then examined for evidence of cross-national convergence in experiences of work humanization. With little indication of any historic convergence apparent the analysis turns to consider the forces which may shape distinctive societal experiences. Quantitative gauges of the shape of the broad political economy are assembled, with a particular attention focused on the quantitative characterisation of the power resources of employees, whether collective or individual. The meaning of these necessarily crude indicators is given extensive consideration. The thesis culminates in separate panel econometric investigations of the political economic characteristics associated with comparative fatal injury incidence and actual annual hours of work. Substantial evidence is presented that the humanization of work is associated with an attenuation of the vulnerability of employees to managerial prerogative

On the measurement of a weak classical force coupled to a quantum-mechanical oscillator. I. Issues of principle

The monitoring of a quantum-mechanical harmonic oscillator on which a classical force acts is important in a variety of high-precision experiments, such as the attempt to detect gravitational radiation. This paper reviews the standard techniques for monitoring the oscillator, and introduces a new technique which, in principle, can determine the details of the force with arbitrary accuracy, despite the quantum properties of the oscillator. The standard method for monitoring the oscillator is the "amplitude-and-phase" method (position or momentum transducer with output fed through a narrow-band amplifier). The accuracy obtainable by this method is limited by the uncertainty principle ("standard quantum limit"). To do better requires a measurement of the type which Braginsky has called "quantum nondemolition." A well known quantum nondemolition technique is "quantum counting," which can detect an arbitrarily weak classical force, but which cannot provide good accuracy in determining its precise time dependence. This paper considers extensively a new type of quantum nondemolition measurement—a "back-action-evading" measurement of the real part X_1 (or the imaginary part X_2) of the oscillator's complex amplitude. In principle X_1 can be measured "arbitrarily quickly and arbitrarily accurately," and a sequence of such measurements can lead to an arbitrarily accurate monitoring of the classical force. The authors describe explicit Gedanken experiments which demonstrate that X_1 can be measured arbitrarily quickly and arbitrarily accurately. In these experiments the measuring apparatus must be coupled to both the position (position transducer) and the momentum (momentum transducer) of the oscillator, and both couplings must be modulated sinusoidally. For a given measurement time the strength of the coupling determines the accuracy of the measurement; for arbitrarily strong coupling the measurement can be arbitrarily accurate. The "momentum transducer" is constructed by combining a "velocity transducer" with a "negative capacitor" or "negative spring." The modulated couplings are provided by an external, classical generator, which can be realized as a harmonic oscillator excited in an arbitrarily energetic, coherent state. One can avoid the use of two transducers by making "stroboscopic measurements" of X_1, in which one measures position (or momentum) at half-cycle intervals. Alternatively, one can make "continuous single-transducer" measurements of X_1 by modulating appropriately the output of a single transducer (position or momentum), and then filtering the output to pick out the information about X_1 and reject information about X_2. Continuous single-transducer measurements are useful in the case of weak coupling. In this case long measurement times are required to achieve good accuracy, and continuous single-transducer measurements are almost as good as perfectly coupled two-transducer measurements. Finally, the authors develop a theory of quantum nondemolition measurement for arbitrary systems. This paper (Paper I) concentrates on issues of principle; a sequel (Paper II) will consider issues of practice