The effectiveness of the Canadian mandatory seat belt use laws

The impact of four provincial mandatory seat belt use laws passed in 1976 and 1977 on seat belt use and on motor vehicle occupant casualties is examined. Subsequent to the passage of the laws, belt use typically increased from 20 to the 70% level dropping to around 50% over the next several years. Ontario exhibited a clear drop in the fatality and injury rates in the years following the introduction of the law. Quebec experienced little reduction in casualties. The changes in casualties for British Columbia and Saskatchewan were mixed with the former showing a drop only in the fatality rate subsequent to the seat belt law, while the latter experienced a reduction only in the injury rate. The provinces without seat belt use laws also enjoyed some reductions in occupant casualty rates. The changes in occupant casualties in the legislated provinces were also examined relative to the changes in non-occupant casualties and relative to the unlegislated provinces. It was concluded that three provinces experienced some reductions as a result of legislation but not as much as anticipated. It is speculated that the impact of the seat belt use laws fell short of expectations because it was mainly the safe drivers who buckled up in response to the laws.     

SPROUT—A Modeling Language for SEED

An important capability of the SEED system is rapid generation of internal design representations, including design alternatives, that can be evaluated in terms of a broad range of criteria. It consists of modules that must communicate with each other and remain extensible. From a software engineering perspective, there exists no single programming language or database management system, commercial or research-based, that provides all the needed support. In this paper, we describe the SPROUT modeling language, the cornerstone of efforts to bridge this gap. It supports the specification of a system information model, which contains a building product model as a subset. Developments are discussed that lead to the current language design as well as the support for case-based design, persistent storage of objects, management of versions and alternatives, and communication between different SEED modules (i.e., agents). Emphasis is placed on the automatic generation of computer programs and database schemas from a SPROUT specification. Lastly, this effort is compared to other comparable efforts including PDES∕STEP.     

The effect of Knudsen layers on rarefied cylindrical Couette gas flows

We investigate a power-law probability distribution function to describe the mean free path of rarefied gas molecules in non-planar geometries. A new curvature-dependent model is derived by taking into account the boundary-limiting effects on the molecular mean free path for surfaces with both convex and concave curvatures. The Navier–Stokes constitutive relations and the velocity-slip boundary conditions are then modified based on this power-law scaling through the transport property expressions in terms of the mean free path. Velocity profiles for isothermal cylindrical Couette flow are obtained using this power-law model and compared with direct simulation Monte Carlo (DSMC) data. We demonstrate that our model is more accurate than the classical slip solution, and we are able to capture important non-linear trends associated with the non-equilibrium physics of the Knudsen layer. In addition, we establish a new criterion for the critical accommodation coefficient that leads to the non-intuitive phenomenon of velocity inversion. The power-law model predicts that the critical accommodation coefficient is significantly lower than that calculated using the classical slip solution, and is in good agreement with available DSMC data. Our proposed constitutive scaling for non-planar surfaces is based on simple physical arguments and can be readily implemented in conventional fluid dynamics codes for arbitrary geometric configurations of microfluidic systems.     

Geometric characterization of nanoporous metals

Nanoporous metals made by dealloying possess significant geometric complexity—they are random, bicontinuous structures that also possess bubbles within ligaments, regions of very high negative, positive, and saddlepoint curvature, and significant polyfaceting. Here we introduce methods to geometrically quantify the structure of nanoporous metals employing simulated model nanoporous metals generated via large-scale kinetic Monte Carlo simulations as the basis of discussion. A method is introduced to transform these simulated structures into smooth triangulated meshes using new mesh-smoothing algorithms that hybridize mean curvature flow and signal processing approaches to mesh fairing. The technique is assessed by comparing the exact genus of high-genus meshes with the genus calculated via the Gauss–Bonnet formula, and works well to find the local curvature at all points of simulated surfaces of high topological genus. Specific geometric quantification of nanoporous metals is discussed for two quantities: (i) the relative surface area fraction of different crystal facets, which is important for catalysis; and (ii) the curvature distribution on the surface of porous metals, important for applications in which high curvature features are active (e.g. optical sensing).     

Liquid slip/stick over hydrophobic/hydrophilic surfaces and their implications in coating processes

Fluid slip has been observed experimentally in micro- and nanoscale liquid flow devices by several investigators. While observations of fluid slip continue to expand, the generating mechanism responsible for fluid slip is not well understood and indeed generalized mathematical formulation is not available. In the present paper, the author gave an attempt to explain the generating mechanism for the fluid slip on hydrophobic surface. The importance of the present theory lies in the fact that it obviates the need to impose the ad hoc Newtons slip at the fluid–wall interface and also the pre-assumption of thin gas layer close to the wall. Surface interactions with the liquid/fluid at molecular scale are incorporated together with the phase field theory to accurately predict the phase of the fluid close to the wall, which is imperative to accurately determine the fluid slip close to the wall. It is noticed that the incorporation of these molecule–surface interactions have significant effect on the resulting coating windows on both hydrophobic and hydrophilic substrates, however it is more predominant for the hydrophobic one.     

A LINEAR CORRELATION FOR SOLID SOLUBILITIES IN SUPERCRITICAL GASES

A previously derived equation (Jonah, 1986) for solid solubilities in supercritical gases is tested in empirically abbreviated form against experimental data on six solutes in supercritical ethylene and carbon dioxide. The solids considered are benzoic acid, 2,3- and 2,6-dimethylnaphthalene, naphthalene, phenanthrene and anthracene.

Our equation correlates these solid solubilities linearly with certain functions of pure solvent thermodynamic properties, thereby making possible the interpolation and extrapolation of sparse experimental data.     

A stochastic mathematical model of 4D tumour spheroids with real-time fluorescent cell cycle labelling

In vitro tumour spheroids have been used to study avascular tumour growth and drug design for over 50 years. Tumour spheroids exhibit heterogeneity within the growing population that is thought to be related to spatial and temporal differences in nutrient availability. The recent development of real-time fluorescent cell cycle imaging allows us to identify the position and cell cycle status of individual cells within the growing spheroid, giving rise to the notion of a four-dimensional (4D) tumour spheroid. We develop the first stochastic individual-based model (IBM) of a 4D tumour spheroid and show that IBM simulation data compares well with experimental data using a primary human melanoma cell line. The IBM provides quantitative information about nutrient availability within the spheroid, which is important because it is difficult to measure these data experimentally.     

Minor Changes for a Major Impact: A Review of Epigenetic Modifications in Cell-Based Therapies for Stroke

Epigenetic changes in stroke may revolutionize cell-based therapies aimed at reducing ischemic stroke risk and damage. Epigenetic changes are a novel therapeutic target due to their specificity and potential for reversal. Possible targets for epigenetic modification include DNA methylation and demethylation, post-translational histone modification, and the actions of non-coding RNAs such as microRNAs. Many of these epigenetic modifications have been reported to modulate atherosclerosis development and progression, ultimately contributing to stroke pathogenesis. Furthermore, epigenetics may play a major role in inflammatory responses following stroke. Stem cells for stroke have demonstrated safety in clinical trials for stroke and show therapeutic benefit in pre-clinical studies. The efficacy of these cell-based interventions may be amplified with adjunctive epigenetic modifications. This review advances the role of epigenetics in atherosclerosis and inflammation in the context of stroke, followed by a discussion on current stem cell studies modulating epigenetics to ameliorate stroke damage.     

Durable Transition‐Metal‐Carbide‐Supported Pt–Ru Anodes for Direct Methanol Fuel Cells

Molybdenum carbide (MoC) and tungsten carbide (WC) are synthesized by direct carbonization method. Pt–Ru catalysts supported on MoC, WC, and Vulcan XC‐72R are prepared, and characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, and transmission electron microscopy in conjunction with electrochemistry. Electrochemical activities for the catalysts towards methanol electro‐oxidation are studied by cyclic voltammetry. All the electro‐catalysts are subjected to accelerated durability test (ADT). The electrochemical activity of carbide‐supported electro‐catalysts towards methanol electro‐oxidation is found to be higher than carbon‐supported catalysts before and after ADT. The study suggests that Pt–Ru/MoC and Pt–Ru/WC catalysts are more durable than Pt–Ru/C. Direct methanol fuel cells (DMFCs) with Pt–Ru/MoC and Pt–Ru/WC anodes also exhibit higher performance than the DMFC with Pt–Ru/C anode.     

Analytical solution of plane Poiseuille flow within Burnett hydrodynamics

In the current paper, low-speed isothermal microscale gas flows have been investigated utilizing the augmented Burnett equations. There has been limited success to analytically solve the Burnett equations till date. We propose an analytical solution to Burnett equations, which is shown to satisfy the full set of augmented Burnett equations up to Kn of 2.2 with an error of 1 %. Detailed validation shows that the solution represents the integral flow parameters accurately up to Kn ~ 2.2 and local field properties up to Kn ~ 0.5. The range over which the proposed Burnett analytical solution is applicable is substantially better than existing analytical solutions, without incorporating any wall scaling functions into constitutive relations and variation of slip coefficients in the boundary conditions. Normalized mass flow rate, friction factor, and axial velocity profile results show very good agreement with the experimental and simulation data. The analytical solution is also able to predict the change in the curvature of streamwise pressure profile.