Experimental study on a metal hydride based hydrogen compressor

This is the post-print version of the final paper published in Journal of Alloys and Compounds. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2008 Elsevier B.V.A three-stage metal hydride based hydrogen compressor prototype was built. It has been designed for a hydrogen production facility using a low-pressure alkaline electrolyser. The compression system should transfer heat recovered from the electrolyser into the hydride beds to allow hydrogen desorption flow. The three-stage compressor achieves a compression ratio of 20:1 atm. It performs a thermal cycling of three AB5 hydrides between 20 and 80 °C. Its flow rate, for 25 g of each hydride bed, reaches about 20 l (NTP) of hydrogen per hour. The prototype is now operational. Some improvements in the heat transfer management system are also carried out before proceeding to the interconnection with the electrolyser and to the extent that the hydrogen produced satisfies the high purity requirement of the hydrides used in the compressor.Natural Resources Canada(NRCan), Ministère des Ressources Naturelles et de la Faune du Québec (MRNF), and Natural Sciences and Engineering Research Council of Canada

Le nombre de permutations dans les tests permutationnels; The number of permutations in permutation tests

In a first part, the concepts and theory of exact randomization tests are reviewed, together with their implementation for each of a number of customary test situations including simple anova designs. Approximate (or incomplete) randomization tests are considered in the second part, as manageable alternatives to exact tests. We propose a model to calculate the relative power of approximate randomization tests and sketch out some guidelines for the user

The discriminating capacity of a measuring instrument: Revisiting Bloom (1942)s theory and formula

Discriminating capacity is defined as a property of a test, measuring device or scholastic exam, which enables us to segregate and categorize objects or people according to their measured values. The concept, anticipated by Bloom and derived here from Fergusons index of classificatory power, is developed upon three bases: the probability of categorizing an object (or person) in its proper measuring interval; the sufficient length of measuring intervals; the number of efficacious intervals in an empirical or theoretical distribution of measures. Expressed as a function of the reliability coefficient of a measuring device, discriminating capacity appears as a new tool in the conceptual apparatus of classical test theory

The exact binomial test between two independent proportions: A companion

This note, a summary in English of a former article in French (Laurencelle, 2017), presents an outline of the theory and implementation of an exact test of the difference between two binomial variables. Essential formulas are provided, as well as two executable computer programs, one in Delphi, the other in R

Analysis of frequency data: The ANOFA framework

Analyses of frequencies are commonly done using a chi-square test. This test, derived from a normal approximation, is deemed generally efficient (controlling type-I error rates fairly well and having good statistical power). However, in the case of factorial designs, it is difficult to decompose a total test statistic into additive interaction effects and main effects. Herein, we present an alternative test based on the $G$ statistic. The test has similar type-I error rates and power as the former one. However, it is based on a total statistic that is naturally decomposed additively into interaction effects, main effects, simple effects, contrast effects, etc., mimicking precisely the logic of ANOVAs. We call this set of tools ANOFA (Analysis of Frequency data) to highlight its similarities with ANOVA. We also examine how to render plots of frequencies along with confidence intervals. Finally, quantifying effect sizes and planning statistical power are described under this framework. The ANOFA is a tool that assesses the significance of effects instead of the significance of parameters; as such, it is more intuitive to most researchers than alternative approaches based on generalized linear models

Chronic low back pain clinical outcomes present higher associations with the STarT Back Screening Tool than with physiologic measures: a 12-month cohort study

Stratification strategies based on identifying patient's prognosis in order to guide patient care constitute one of the most prominent and recent approach in low back pain research. The STarT Back Screening Tool (SBST) although promising, has not been studied in patients with chronic low back pain (cLBP). Considering how challenging it is to translate research into practice, the value of integrating a new tool should be thoroughly assessed. The purpose was therefore to assess associations between the short- and long-terms clinical status and two types of variables, physiologic measures and the SBST, in participants with cLBP. The ability of both types of variables to discriminate between participants with and without higher levels of disability, pain, fear of movement and patient's global impression of change was also investigated