Why Secondary Schools Do Not Implement Far-Reaching Smoke-Free Policies: Exploring Deep Core, Policy Core, and Secondary Beliefs of School Staff in the Netherlands

Background: Secondary schools that implement smoke-free policies are confronted with students who start smoking outside their premises. One solution is to complement smoke-free policies with prohibitions for all students to leave the school area during school hours, technically making school hours a smoke-free period. However, there are strikingly few Dutch secondary schools that implement this approach. This study explores why staff members in the Netherlands decide not to implement smoke-free school hours for all students. Method: We interviewed 13 staff members, with different functions, from four secondary schools. The analysis was informed by the Advocacy Coalition Framework (ACF) to delve into the values, rationales, and assumptions of staff with the aim to identify deep core, policy core, and secondary beliefs. Results: We identified six beliefs. Two deep core beliefs are that schools should provide adolescents the freedom to learn how to responsibly use their personal autonomy and that schools should only interfere if adolescents endanger or bother others. Three policy core beliefs identified included the following: that smoking is not a pressing issue for schools to deal with; that schools should demarcate their jurisdiction to intervene in adolescents’ lives in time, space, and precise risk behavior; and that implementing smoke-free school hours would interfere with maintaining positive student-staff relationships. One secondary belief identified was that smoke-free school hours would be impossible to enforce consistently. Conclusion: This paper was the first to demonstrate the many beliefs explaining why schools refrain from voluntary implementing far-reaching smoke-free policies

An optical method to determine the thermodynamics of hydrogen absorption and desorption in metals

Hydrogenography, an optical high-throughput combinatorial technique to find hydrogen storage materials, has so far been applied only to materials undergoing a metal-to-semiconductor transition during hydrogenation. We show here that this technique works equally well for metallic hydrides. Additionally, we find that the thermodynamic data obtained optically on thin Pd-H films agree very well with Pd-H bulk data. This confirms that hydrogenography is a valuable general method to determine the relevant parameters for hydrogen storage in metal hydrides. © 2007 American Institute of Physics

Mg/Ti multilayers: structural, optical and hydrogen absorption properties

Mg-Ti alloys have uncommon optical and hydrogen absorbing properties, originating from a "spinodal-like" microstructure with a small degree of chemical short-range order in the atoms distribution. In the present study we artificially engineer short-range order by depositing Pd-capped Mg/Ti multilayers with different periodicities and characterize them both structurally and optically. Notwithstanding the large lattice parameter mismatch between Mg and Ti, the as-deposited metallic multilayers show good structural coherence. Upon exposure to H2 gas a two-step hydrogenation process occurs, with the Ti layers forming the hydride before Mg. From in-situ measurements of the bilayer thickness L at different hydrogen pressures, we observe large out-of-plane expansions of the Mg and Ti layers upon hydrogenation, indicating strong plastic deformations in the films and a consequent shortening of the coherence length. Upon unloading at room temperature in air, hydrogen atoms remain trapped in the Ti layers due to kinetic constraints. Such loading/unloading sequence can be explained in terms of the different thermodynamic properties of hydrogen in Mg and Ti, as shown by diffusion calculations on a model multilayered systems. Absorption isotherms measured by hydrogenography can be interpreted as a result of the elastic clamping arising from strongly bonded Mg/Pd and broken Mg/Ti interfaces

Mg-Ti-H thin films for smart solar collectors

Mg-Ti-H thin films are found to have very attractive optical properties: they absorb 87% of the solar radiation in the hydrogenated state and only 32% in the metallic state. Furthermore, in the absorbing state Mg-Ti-H has a low emissivity; at 400 K only 10% of blackbody radiation is emitted. The transition between both optical states is fast, robust, and reversible. The sum of these properties highlights the applicability of such materials as switchable smart coatings in solar collector

Structural and optical properties of Mg_xAl_1-xH_y gradient thin films: a combinatorial approach

The structural, optical and dc electrical properties of MgxAl1-x (0.2≤x≤0.9) gradient thin films covered with Pd/Mg are investigated before and after exposure to hydrogen. We use hydrogenography, a novel high-throughput optical technique, to map simultaneously all the hydride forming compositions and the kinetics thereof in the gradient thin film. Metallic Mg in the MgxAl1-x layer undergoes a metal-to-semiconductor transition and MgH₂ is formed for all Mg fractions x investigated. The presence of an amorphous Mg-Al phase in the thin film phase diagram enhances strongly the kinetics of hydrogenation. In the Al-rich part of the film, a complex H-induced segregation of MgH₂ and Al occurs. This uncommon large-scale segregation is evidenced by metal and hydrogen profiling using Rutherford backscattering spectrometry and resonant nuclear analysis based on the reaction ¹H(¹⁵N,αγ)¹²C. Besides MgH₂, an additional semiconducting phase is found by electrical conductivity measurements around an atomic [Al]/[Mg] ratio of 2 (x=0.33). This suggests that the film is partially transformed into Mg(AlH₄)₂ at around this composition