Design strategies for sustainable buildings, that improve building performance and avoid extensive resource utilization, should also promote healthy indoor environments. The following paper contains ...a review of the couplings between (1) building design, (2) indoor environmental quality and (3) occupant behavior. The paper focuses on defining the limits of adaptation on the three aforementioned levels to ensure the energy efficiency of the whole system and healthy environments. The adaptation limits are described for measurable physical parameters and the relevant responsible human sensory systems, evaluating thermal comfort, visual comfort, indoor air quality and acoustical quality. The goal is to describe the interactions between the three levels where none is a passive participant, but rather an active agent of a wider human-built environment system. The conclusions are drawn in regard to the comfort of the occupant. The study reviews more than 300 sources, ranging from journals, books, conference proceedings, and reports complemented by a review of standards and directives.
Homochirality is a fundamental feature of living systems, and its origin is still an unsolved mystery. Previous investigations showed that external physical forces can bias a spontaneous symmetry ...breaking process towards deterministic enantioselection. But can the macroscopic shape of a reactor play a role in chiral symmetry breaking processes? Here we show an example of chirality transfer from the chiral shape of a 3D helical channel to the chirality of supramolecular aggregates, with the handedness of the helical channel dictating the direction of enantioselection in the assembly of an achiral molecule. By combining numerical simulations of fluid flow and mass transport with experimental data, we demonstrated that the chiral information is transferred top-down thanks to the interplay between the hydrodynamics of asymmetric secondary flows and the precise spatiotemporal control of reagent concentration fronts. This result shows the possibility of controlling enantioselectively molecular processes at the nanometer scale by modulating the geometry and the operating conditions of fluidic reactors.
To provide perspectives from the HEAT-SHIELD project (www.heat-shield.eu): a multi-national, inter-sectoral, and cross-disciplinary initiative, incorporating twenty European research institutions, as ...well as occupational health and industrial partners, on solutions to combat negative health and productivity effects caused by working on a warmer world.
In this invited review, we focus on the theoretical and methodological advancements developed to combat occupational heat stress during the last five years of operation.
We outline how we created climate forecast models to incorporate humidity, wind and solar radiation to the traditional temperature-based climate projections, providing the basis for timely, policy-relevant, industry-specific and individualized information. Further, we summarise the industry-specific guidelines we developed regarding technical and biophysical cooling solutions considering effectiveness, cost, sustainability, and the practical implementation potential in outdoor and indoor settings, in addition to field-testing of selected solutions with time-motion analyses and biophysical evaluations. All recommendations were adjusted following feedback from workshops with employers, employees, safety officers, and adjacent stakeholders such as local or national health policy makers. The cross-scientific approach was also used for providing policy-relevant information based on socioeconomic analyses and identification of vulnerable regions considered to be more relevant for political actions than average continental recommendations and interventions.
From the HEAT-SHIELD experiences developed within European settings, we discuss how this inter-sectoral approach may be adopted or translated into actionable knowledge across continents where workers and societies are affected by escalating environmental temperatures.
Abstract
Control over the functionalization of graphenic materials is key to enable their full application in electronic and optical technologies. Covalent functionalization strategies have been ...proposed as an approach to tailor the interfaces’ structure and properties. However, to date, none of the proposed methods allow for a covalent functionalization with control over the grafting density, layer thickness and/or morphology, which are key aspects for fine-tuning the processability and performance of graphenic materials. Here, we show that the no-slip boundary condition at the walls of a continuous flow microfluidic device offers a way to generate controlled chemical gradients onto a graphenic material with 2D and 3D control, a possibility that will allow the sophisticated functionalization of these technologically-relevant materials.
To date, crystallization studies conducted in space laboratories, which are prohibitively costly and unsuitable to most research laboratories, have shown the valuable effects of microgravity during ...crystal growth and morphogenesis. Herein, an easy and highly efficient method is shown to achieve space‐like experimentation conditions on Earth employing custom‐made microfluidic devices to fabricate 2D porous crystalline molecular frameworks. It is confirmed that experimentation under these simulated microgravity conditions has unprecedented effects on the orientation, compactness and crack‐free generation of 2D porous crystalline molecular frameworks as well as in their integration and crystal morphogenesis. It is believed that this work will provide a new “playground” to chemists, physicists, and materials scientists that desire to process unprecedented 2D functional materials and devices.
How to achieve simulated microgravity conditions on Earth? The art of growing and processing 2D porous crystalline molecular frameworks in simulated microgravity is presented.
Covalent organic frameworks (COFs) are an emerging class of two-dimensional (2D) or three-dimensional (3D) porous structures. Most COFs are typically prepared via solvothermal methods involving long ...reaction times (>12 h) that generally result in unprocessable powders, significantly hindering their straightforward integration into devices and applications. Current processing methods for 2D COFs have not been implemented for 3D COFs, probably due to the lack of preassembly mechanisms among the 3D COF precursors during synthesis. Here, we report a pioneering synthetic environment that achieves two objectives: precise control over the reaction time of 3D COF precursors through controlled diffusion, ensuring the absence of turbulent mixing, and the ability to fine-tune the specific reaction zone where the reaction and controlled diffusion of the 3D COF precursors will occur. We further demonstrate that controlling these two features in 3D creates an unparalleled synthetic environment, allowing for a rapid one-pot synthesis of 3D COFs, with their formation occurring in less than a minute. Additionally, this approach yields self-standing 3D COF fibers on a centimeter scale, showcasing the versatility and potential of the approach presented for scalable production of 3D COFs as well as for their seamless integration into devices and patterning strategies.
A methodology that can be efficiently used to synthesize, isolate, and study out‐of‐equilibrium crystal structures employing controlled and diffusion‐limited microfluidic environments is ...demonstrated. Unlike studies conducted with conventional mixing procedures in a flask, it is proven experimentally and with numerical simulations that microfluidic technologies can undoubtedly fine‐tune reaction times and reagents concentration profiles; factors that enable out‐of‐equilibrium crystal forms to be obtained.
Fine control over the growth of materials is required to precisely tailor their properties. Spatial atomic layer deposition (SALD) is a thin-film deposition technique that has recently attracted ...attention because it allows producing thin films with a precise number of deposited layers, while being vacuum-free and much faster than conventional atomic layer deposition. SALD can be used to grow films in the atomic layer deposition or chemical vapor deposition regimes, depending on the extent of precursor intermixing. Precursor intermixing is strongly influenced by the SALD head design and operating conditions, both of which affect film growth in complex ways, making it difficult to predict the growth regime prior to depositions. Here, we used numerical simulation to systematically study how to rationally design and operate SALD systems for growing thin films in different growth regimes. We developed design maps and a predictive equation allowing us to predict the growth regime as a function of the design parameters and operation conditions. The predicted growth regimes match those observed in depositions performed for various conditions. The developed design maps and predictive equation empower researchers in designing, operating, and optimizing SALD systems, while offering a convenient way to screen deposition parameters, prior to experimentation.
The main objective of the study was to investigate the thermal performance of five (open and closed) bicycle helmets for convective and evaporative heat transfer using a nine-zone thermal manikin. ...The shape of the thermal manikin was obtained by averaging the 3D-point coordinates of the head over a sample of 85 head scans of human subjects, obtained through magnetic resonance imaging (MRI) and 3D-printed. Experiments were carried out in two stages, (i) a convective test and (ii) an evaporative test, with ambient temperature maintained at 20.5 ± 0.5 °C and manikin skin temperature at 30.5 ± 0.5 °C for both the tests. Results showed that the evaporative heat transfer contributed up to 51%–53% of the total heat loss from the nude head. For the convective tests, the open helmet A1 having the highest number of vents among tested helmets showed the highest cooling efficiency at 3 m/s (100.9%) and at 6 m/s (101.6%) and the closed helmet (A2) with fewer inlets and outlets and limited internal channels showed the lowest cooling efficiency at 3 m/s (75.6%) and at 6 m/s (84.4%). For the evaporative tests, the open helmet A1 showed the highest cooling efficiency at 3 m/s (97.8%), the open helmet A4 showed the highest cooling efficiency at 6 m/s (96.7%) and the closed helmet A2 showed the lowest cooling efficiency at 3 m/s (79.8%) and at 6 m/s (89.9%). Two-way analysis of variance (ANOVA) showed that the zonal heat-flux values for the two tested velocities were significantly different (p < 0.05) for both the modes of heat transfer. For the convective tests, at 3 m/s, the frontal zone (256–283 W/m2) recorded the highest heat flux for open helmets, the facial zone (210–212 W/m2) recorded the highest heat flux for closed helmets and the parietal zone (54–123 W/m2) recorded the lowest heat flux values for all helmets. At 6 m/s, the frontal zone (233–310 W/m2) recorded the highest heat flux for open helmets and the closed helmet H1, the facial zone (266 W/m2) recorded the highest heat flux for the closed helmet A2 and the parietal zone (65–123 W/m2) recorded the lowest heat flux for all the helmets. For evaporative tests, at 3 m/s, the frontal zone (547–615 W/m2) recorded the highest heat flux for all open helmets and the closed helmet H1, the facial zone (469 W/m2) recorded the highest heat flux for the closed helmet A2 and the parietal zone (61–204 W/m2) recorded the lowest heat flux for all helmets. At 6 m/s, the frontal zone (564–621 W/m2) recorded highest heat flux for all the helmets and the parietal zone (97–260 W/m2) recorded the lowest heat flux for all helmets.
A review on ergonomics of headgear: Thermal effects Bogerd, Cornelis P.; Aerts, Jean-Marie; Annaheim, Simon ...
International journal of industrial ergonomics,
02/2015, Letnik:
45, Številka:
February
Journal Article
Recenzirano
Odprti dostop
The thermal effects related to wearing headgear are complex and different studies have investigated single parts of this topic. This review aims at summarizing the different findings to give a ...complete overview on this topic as well as to suggest new perspectives. Headgear increases head insulation and therefore is mainly problematic under warm conditions, which is the focus of this review. Helmets do not affect physiological parameters other than the local skin temperature and sweat rate. However, the head is among the most sensitive body parts related to thermal comfort, thereby directly affecting the willingness to wear headgear. Several methods have been used to study thermal aspects of headgear, which could be categorized as (i) numerical, (ii) biophysical, (iii) combined numerical and biophysical, and (iv) user trials. The application of these methods established that heat transfer mainly takes place through radiation and convection. Headgear parameters relevant to these heat transfer pathways, are reviewed and suggestions are provided for improving existing headgear concepts and developing new concepts, ultimately leading to more accepted headgear.
This review provides a sound basis for improving existing headgear concepts. Firstly, a concise overview of headgear research related to thermal effects is given, leading to empirically based improvement suggestions and identification of research fields with a high potential. Finally, relevant research methods are described facilitating evaluation in R&D processes.
•This paper presents the first literature review on thermal effects of (safety) headgear.•Willingness to use safety headgear is limited by its impact on thermal perception.•Headgear affects local skin temperature and sweat rate but not more generic physiological parameters in warm environments.•Headgear ventilation is a major design option for optimizing thermal performance, several approaches are presented.
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