[en] A potentiometric titration of 5 to 25 mg uranium is described. Sulphamic and phosphoric acid are added to the sample (volume 1 ml), U VI is reduced to U IV by Fe²⁺ and the excess of Fe²⁺ is oxidized by a mixture of nitric acid, sulphamic acid and ammonium molybdate; vanadyl sulphate is added to ensure a sharp end-point of the titration. The resultant U IV is titrated automatically with 0.02500N potassiumdichromate using a platinum indicator electrode. The automatic titration is performed both with a commercial titrator (Mettler) and with an R.C.N. titrator which waits after each addition until the equilibrium is reached. Using the Mettler titrator an accuracy of 0.05% relative was reached. The R.C.N. setpoint titrator gave results with an accuracy of 0.04% relative at the 20-mg U level. Each titration takes 5 to 7 min. (author)

[en] First, let me express my appreciation to Professor Werner for his discussion of my paper. These are quite contentious and fiercely disputed questions, and the only way to make progress in resolving these disputes is to make a good faith effort to present the arguments clearly and explicitly. Only once things are pinned down on paper with some precision can a proper analysis proceed. Werner’s willingness to do this means progress can be made. There are some important points on which Werner and I agree. We agree that neither Einstein nor Bell presuppose determinism in framing their arguments, so the conclusions of those arguments cannot be avoided simply by adopting indeterminism. We even largely agree on what Bell thought he proved. For example, we agree that Bell did not take his theorem to refute determinism or ‘hidden variables’. Werner even seems to concede that Bell himself thought that he had proven the necessity for any theory that reproduces the predictions of the quantum formalism—or more generally any theory that predicts violations of his inequality for pairs of experiments done at space-like separation—to be non-local (in a particular sense of ‘non-local’). Agreement on this much is already a tremendous amount of progress, and I do not wish to undervalue it

[en] Practical algorithms are presented for the parameterization of orthogonal matrices Q ∈ R ^m×n in terms of the minimal number of essential parameters (φ). Both square n = m and rectangular n < m situations are examined. Two separate kinds of parameterizations are considered, one in which the individual columns of Q are distinct, and the other in which only Span(Q) is significant. The latter is relevant to chemical applications such as the representation of the arc factors in the multifacet graphically contracted function method and the representation of orbital coefficients in SCF and DFT methods. The parameterizations are represented formally using products of elementary Householder reflector matrices. Standard mathematical libraries, such as LAPACK, may be used to perform the basic low-level factorization, reduction, and other algebraic operations. Some care must be taken with the choice of phase factors in order to ensure stability and continuity. The transformation of gradient arrays between the Q and (φ) parameterizations is also considered. Operation counts for all factorizations and transformations are determined. Numerical results are presented which demonstrate the robustness, stability, and accuracy of these algorithms

No abstract available

[en] Possible sources of systematic error in solar Doppler rotational velocities are examined. Scattered light is shown to affect the Mount Wilson solar rotation results, but this effect is not enough to bring the spectroscopic results in coincidence with the sunspot rotation. Interference fringes at the spectrograph focus at Mount Wilson have in two intervals affected the rotation results. It has been possible to correlate this error with temperature and thus correct for it. A misalignment between the entrance and exit slits is a possible source of error, but for the Mount Wilson slit configuration the amplitude of this effect is negligibly small. Rapid scanning of the solar image also produces no measurable effect. (orig.)

[en] We investigate the effects of the saturation boundary on small-x evolution at the next-to-leading order accuracy and beyond. We demonstrate that the instabilities of the next-to-leading order BFKL evolution are not cured by the presence of the nonlinear saturation effects, and a resummation of the higher order corrections is therefore needed for the nonlinear evolution. The renormalization group improved resummed equation in the presence of the saturation boundary is investigated, and the corresponding saturation scale is extracted. A significant reduction of the saturation scale is found, and we observe that the onset of the saturation corrections is delayed to higher rapidities. This seems to be related to the characteristic feature of the resummed splitting function which at moderately small values of x possesses a minimum.

[en] The accuracy and reproducibility of a flow device depends on two areas, one of which is a knowledge of the parameters needed to describe the flow rates through the device. This paper represents an effort to understand the parameters needed to describe the flow rate through a laminar flowmeter. Results indicate that better than 0.1% precision can be achieved for short periods (days). 7 figures

[en] An overview of the theory and techniques of radiometric thermometry is presented. The characteristics of thermal radiators (targets) are discussed along with surface roughness and oxidation effects, fresnel reflection and subsurface effects in dielectrics. The effects of the optical medium between the radiating target and the radiation thermometer are characterized including atmospheric effects, ambient temperature and dust environment effects and the influence of measurement windows. The optical and photodetection components of radiation thermometers are described and techniques for the correction of emissivity effects are addressed

[en] Nowadays, disruption predictors, based on machine learning techniques, can perform well but they typically do not provide any information about the type of disruption and cannot predict the time remaining before the current quench. On the other hand, the automatic identification of the disruption type is a crucial aspect required to optimize the remedial actions and a prerequisite to forecasting the time left for intervening. In this work, a stack of machine learning tools is applied to the task of automatic classification of the disruption types. The strategy is implemented from scratch and completely adaptive; the predictors start operating after the first disruption and update their own models, following the evolution of the experimental program, without any human intervention. Moreover, they are designed to implement a form of transfer learning, in the sense that they identify autonomously the most important disruption classes, generating new ones when necessary. The results obtained are very encouraging in terms of both prediction performance and classification accuracy. On the other hand, regarding the narrowing of the warning times, some progress has been achieved, but new techniques will have to be devised to obtain fully satisfactory properties. (paper)

[en] FOCal Underdetermined System Solver (FOCUSS) is a useful method through reweighted ℓ_2 minimization for sparse recovery. In this paper, we introduce an improved FOCUSS by enhancing sparsity with two reweighted ℓ_2 minimization. The reweighted FOCUSS method has higher mission success rate and better accuracy than FOCUSS. The simulation results illustrate the advantage of reweighted FOCUSS