Excess micromotion compensation of trapped ions in a linear Paul trap for trace isotope analysis

Excess micromotion of trapped calcium ions was detected and compensated in our linear Paul trap apparatus for trace isotope analysis. The micromotion was detected by Charge-coupled device (CCD). camera and radio frequency (rf) correlation method. We found that 230 and 2280 V of compensation voltages were needed for x- and y-axis compensation in our apparatus, respectively. The z-axis micromotion was confirmed by the experiment and its cause was investigated by finding a shape of z-axis confinement field. The confinement field was indeed distorted in our apparatus and it gave rise to the trapped ion to shift from potential center. And the micromotion of r-direction was transferred to the z-axis by the distorted confinement field. The z-axis micromotion was suppressed by increasing cap voltage of trap.     

Durability of rammed earth walls exposed for 20 years to natural weathering

This paper presents a study on the durability of different types of stabilised and unstabilised rammed earth walls. These rammed earth walls were constructed and exposed for 20 years to natural weathering, in a wet continental climate. None of these walls have shown complete collapse to date. A method to measure the rammed earth walls erosion by stereo-photogrammetry has been developed. The result shows that the mean erosion depth of the studied walls is about 2 mm (0.5% wall thickness) in the case of rammed earth wall stabilised with 5% by dry weight of hydraulic lime and about 6.4 mm (1.6% wall thickness) in the case of unstabilised rammed earth walls. The stabilisation enables to not use any plaster to protect the walls. In the case of the unstabilised rammed earth walls, an extrapolated lifetime longer than 60 years can be assessed. This shows a potential for the use of unstabilised rammed earth in the similar climatic conditions with this study. The method of stereo-photogrammetry used to measure the erosion of rammed earth walls on site may also help to calibrate and develop more pertinent laboratory test to assess the durability of rammed earth wall.     

Ensuring visibility in calibration-free path planning for image-based visual servoing

We consider the problem of planning a path for image-based eye-in-hand visual servoing applications, when using an uncalibrated camera. Recent developments in this field lead to analytical interpolation between two views of an unknown object, in the projective space. Literature also provides extensions of these approaches that account for the target visibility constraint. Unfortunately, these extensions require an (even weakly) calibrated camera, and involve iterative algorithms that are not proven to converge. In this paper, we propose a modification of an existing projective interpolation algorithm that guarantees the visibility of the observed target, while avoiding the use of any knowledge on the camera calibration parameters, nor on the observed object.     

Efficient compilation of array iterators for Lustre

In this paper, we present a compilation scheme along with optimizations for array iterators in the synchronous data flow language Lustre. We present the iterators (inspired from functional languages mechanisms such as map and foldl…) and show how to compile them into efficient imperative code that manipulates arrays and loops instead of inefficient code were arrays are expanded into independent variables.     

Comparison of methods to determine the endogenous amino acid flow at the terminal ileum of the growing rat

The aim was to compare a recently developed peptide alimentation method and the protein-free and regression methods for determining endogenous ileal nitrogen (N) and amino acid excretion in the rat, and to apply the endogenous loss estimates to determine the true ileal digestibility of a meat and bone meal (MBM). Preliminary investigations determined the effect of the time of sampling of digesta after a meal (slaughter method) for rats given a protein-free or an enzymically hydrolysed casein (EHC) based diet, on ileal digesta and endogenous N excretion. There was a significant (P < 0.05) effect of the time of sampling on the amount of digesta collected and the endogenous N excretion for both the EHC and protein-free fed rats. The amount of digesta collected from the terminal 20 cm of ileum and the endogenous N excretion for both the EHC and protein-free fed rats were greatest and least variable at 3 h post-feeding. In the main study, endogenous ileal amino acid excretions were determined in the growing rat fed an EHC-based diet (n = 6) and with subsequent treatment of the digesta using ultrafiltration or in six rats given a protein-free diet or by extrapolation from data for 30 animals given five diets which contained graded levels of MBM as the sole protein source. For the EHC treatment, the ileal digesta precipitate plus retentate was used to determine the endogenous flows. The ultrafiltration step excludes unabsorbed dietary amino acids from the measure of endogenous loss. Chromic oxide was the reference marker in all diets. The endogenous N flows determined by the protein-free and regression methods were similar but both significantly (P < 0.01) lower than those for rats fed the EHC-based diet. The mean endogenous ileal N flows determined by the peptide alimentation method, the protein-free and regression approaches were 1866, 1103 and 1019 μg g^?1 freeze dry matter intake, respectively. The endogenous amino acid flows at the terminal ileum were lower when determined using the traditional protein-free or regression methods. The true ileal digestibility coefficients for MBM were considerably higher based on the EHC versus protein-free endogenous flows.     

Liquid transport through membranes prepared by grafting of polar monomers onto poly(tetrafluoroethylene) films. II. Some factors determining pervaporation rate and selectivity

The effect of some factors including temperature, pressure, film thickness, and grafting ratio on the fractionation of binary liquid mixtures has been investigated by pervaporation through poly(tetrafluoroethylene) films grafted with N-vinylpyrrolidone or 4-vinylpyridine. The purpose was to estimate the best conditions in which the pervaporation process must be carried out. It was concluded that the pervaporation rate is increased at roughly constant selectivity when the temperature of the liquid charge is higher or when the downstream vapor pressure or the film thickness are decreased. A pressure higher than 1 atmosphere above the liquid does not increase the rate. When the grafting ratio is increased, the rate shows a maximum, and for particular conditions, the selectivity becomes much higher.     

Liquid transport through membranes prepared by grafting of polar monomers onto poly(tetrafluoroethylene) films. III. Steady-state distribution in membrane during pervaporation

Steady-state concentration and composition gradients of pervaporating liquids inside the membranes were measured using stacks of membranes. The experimental results on pure components agree well with a simple mechanism of diffusion down a chemical potential gradient in a nonporous membrane. For mixtures, concentration gradients are similar to those obtained for pure liquids, and composition distribution shows that the selection between the two species does not take place at a given interface in the membrane but is progressive along the diffusional paths through the membrane. Data are also listed to show that solubility and diffusivity enhancements occur for components which are hydrogen bonded with the basic groups of the membrance.     

Solvation in hydroorganic media—II. Gibbs free energy of transfer for HCl and comparison between Rb+ and H+ ions

A previously derived method for the determination of Gibbs free energies of transfer of alkali chlorides using cationic glass electrodes is applied to the transfer of HCl, and results for the transfer of HCl from water to a large number of water-organic solvent mixtures are reported. The accuracy of the proposed method is critically discussed. Relations for the Gibbs free energies of transfer of RbCl and HCl in various aqueous organic media, based on some classical models, are compared. A basicity scale for the organic cosolvents used was derived, based on the theory of Pleskov[19].