High purity pion beam at TRIUMF

An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay π⁺→e⁺ν is also described.     

Thermal and mechanical analysis of the ITER plasma-position reflectometry antennas

The antennas of the ITER plasma-position reflectometer are the components most exposed to the plasma. High thermal loads can cause high temperatures and excessive stress, so the first constrains on the antenna design arise from thermal simulations results. Therefore, the first step of the analysis is to develop a finite element thermal model with ANSYS. Once the temperatures are kept at acceptable levels, structural analysis is performed to know the thermal stress. Simulations performed using different materials and support structure geometries are discussed. Further, it has been checked that the components can withstand the electromagnetic loads expected during disruptions and vertical displacement events. The stress due to these electromagnetic loads is calculated analytically as well as with ANSYS simulations. The proposed antenna arrangement is properly designed against thermal and mechanical loads.     

A Bayesian nonparametric study of a dynamic nonlinear model

A Bayesian nonparametric approach to modeling a nonlinear dynamic model is presented. New techniques for sampling infinite mixture models are used. The inference procedure specifically in the case of the logistic model and when the nonparametric component is applied to the additive errors is demonstrated.     

Vertical and Radial Consolidation Analysis of Multilayered Soil Using the Spectral Method

A new, easy to implement, solution to the consolidation of multilayered soil based on the spectral method is presented. Combined vertical and radial drainage under instantaneous or single ramp loading is considered, ignoring well resistance. Flow in the vertical direction is based on the average hydraulic gradient at a particular depth which allows smear effects to be included. The excess pore-water pressure profile across all soil layers is described by a single expression calculated with common matrix operations. Average excess pore pressures within or across any number of layers are easily calculated from the single expression. The new model is verified against other solutions from the current literature indicating that the more general spectral method model can replace the separate solutions developed for specific problems.     

Physiological compliance and team performance

Physiological compliance (PC) refers to the correlation between physiological measures of team members over time. The goals of this study were to examine ways of measuring PC in heart rate variability (HRV) data and the relationship between PC and team performance. Teams were tasked with entering both real and simulated rooms and “shooting” individuals with a weapon and identifying individuals without a weapon. The linear correlation and directional agreement PC methods were shown to be the most sensitive to differences in performance, with greater PC being associated with better performance. The correlation method when applied to a measure of respiratory sinus arrhythmia (RSA) revealed a significant difference between high and low performers (t[8] = −2.31, p = 0.03) and the directional agreement applied to inter-beat-intervals and RSA revealed trend-level differences (t[4.62] = −1.86, p = 0.06 and t[8] = −1.68, p = 0.07). These results suggest that PC may have merit for predicting team performance.     

Differential scanning calorimetry studies on coal. 1. Pyrolysis in an inert atmosphere

Results of thermal changes involved during the pyrolysis of twelve US coals of various ranks in a helium atmosphere at 5.6 MPa (gauge) and temperatures up to 580 °C are reported. Thermal effects during pyrolysis of coals ranging in rank from anthracite to HVC bituminous are endothermic in nature over the temperature range investigated. Exothermic heats are observed only in the case of sub-bituminous and lignitic coals. The net thermal effects, that is the resultant of endothermic and exothermic heats, go from endothermic to exothermic with increase in carbon content, a transition occurring around 66% carbon and another in the reverse direction at about 75% carbon. A maximum in exothermicity occurs around 71% carbon and in endothermicity at about 81% carbon. Results have been compared with published DTA data on coals. The fallacy in the interpretation of published DTA thermograms of coals, where weight changes accompany thermal effects, is discussed.     

A general theory of force balancing using counterweights

Three equations are derived in this paper from which the force balance conditions of multi-degree of freedom multi-bar planar linkages may be obtained. The linkages can contain both revolute and prismatic joints, though, as discussed in this paper, there force-balance restrictions associated with prismatic joints.     

Surface modification of polyethylene by photochemical grafting with 2-hydroxyethylmethacrylate

The photochemical grafting of 2-hydroxyethylmethacrylate onto low-density polyethylene film is described. The grafting technique employed involved irradiating a solution of 2-hydroxyethylmethacrylate and benzophenone in acetone spread between films of poly(ethylene terephthalate) or glass and low-density polyethylene. After irradiation for 2 min, the contact angle of the polyethylene films with water fell from 97° to about 50°. The contact angle of the poly(ethylene terephthalate) substrate also fell during grafting. X-ray photoelectron spectroscopy was consistent with the presence of poly(2-hydroxethylmethacrylate) at the surface of the polyethylene. The effect of solvent on the photochemical grafting of 2-hydroxyethylmethacrylate onto low-density polyethylene is discussed. © 1993 John Wiley & Sons, Inc.     

Economics of liquid hydrogen from water electrolysis

Using the data from vendors and open literature, we have constructed a preliminary cost model to predict the cost of liquid hydrogen (LH₂) from water electrolysis. The model has been applied to two LH₂ plants. Both have a production rate of 10 886 kg day⁻¹. The first plant (Plant 1) consists of a tank-type electrolyzer and a liquefier and runs all day at the base-load (or equivalent base-load) power rate. The second (Plant 2) consists of a tank-type electrolyzer, a liquefier, a compressor, and storage vessels. The electrolyzer and the compressor shall run only during the off-peak hours at the off-peak power rate. However, the liquefier shall run all day at the base-load (or equivalent base-load) power rate. The costs of LH₂ from both plants are presented. Unless the base-load power rate is high and the off-peak power rate is substantially low, Plant 1 appears to be economically more feasible than Plant 2.