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111.
Pieter Coenen Genevieve N. Healy Elisabeth A. H. Winkler David W. Dunstan Neville Owen Marj Moodie 《Ergonomics》2018,61(9):1187-1195
We examined the association of musculoskeletal symptoms (MSS) with workplace sitting, standing and stepping time, as well as sitting and standing time accumulation (i.e. usual bout duration of these activities), measured objectively with the activPAL3 monitor. Using baseline data from the Stand Up Victoria trial (216 office workers, 14 workplaces), cross-sectional associations of occupational activities with self-reported MSS (low-back, upper and lower extremity symptoms in the last three months) were examined using probit regression, correcting for clustering and adjusting for confounders. Sitting bout duration was significantly (p < 0.05) associated, non-linearly, with MSS, such that those in the middle tertile displayed the highest prevalence of upper extremity symptoms. Other associations were non-significant but sometimes involved large differences in symptom prevalence (e.g. 38%) by activity. Though causation is unclear, these non-linear associations suggest that sitting and its alternatives (i.e. standing and stepping) interact with MSS and this should be considered when designing safe work systems.
Practitioner summary: We studied associations of objectively assessed occupational activities with musculoskeletal symptoms in office workers. Workers who accumulated longer sitting bouts reported fewer upper extremity symptoms. Total activity duration was not significantly associated with musculoskeletal symptoms. We underline the importance of considering total volumes and patterns of activity time in musculoskeletal research. 相似文献
112.
Pieter Samyn Ahmed Barhoum Thomas Öhlund Alain Dufresne 《Journal of Materials Science》2018,53(1):146-184
The introduction of nanoparticles (NPs) and nanostructured materials (NSMs) in papermaking originally emerged from the perspective of improving processing operations and reducing material consumption. However, a very broad range of nanomaterials (NMs) can be incorporated into the paper structure and allows creating paper products with novel properties. This review is of interdisciplinary nature, addressing the emerging area of nanotechnology in papermaking focusing on resources, chemical synthesis and processing, colloidal properties, and deposition methods. An overview of different NMs used in papermaking together with their intrinsic properties and a link to possible applications is presented from a chemical point of view. After a brief introduction on NMs classification and papermaking, their role as additives or pigments in the paper structure is described. The different compositions and morphologies of NMs and NSMs are included, based on wood components, inorganic, organic, carbon-based, and composite NPs. In a first approach, nanopaper substrates are made from fibrillary NPs, including cellulose-based or carbon-based NMs. In a second approach, the NPs can be added to a regular wood pulp as nanofillers or used in coating compositions as nanopigments. The most important processing steps for NMs in papermaking are illustrated including the internal filling of fiber lumen, LbL deposition or fiber wall modification, with important advances in the field on the in situ deposition of NPs on the paper fibers. Usually, the manufacture of products with advanced functionality is associated with complex processes and hazardous materials. A key to success is in understanding how the NMs, cellulose matrix, functional additives, and processes all interact to provide the intended paper functionality while reducing materials waste and keeping the processes simple and energy efficient. 相似文献
113.
114.
Bohez Steven Daneels Glenn Van Herzeele Lander Van Kets Niels Decrock Sam Geyter Matthias De Van Wallendael Glenn Lambert Peter Dhoedt Bart Simoens Pieter Latré Steven Famaey Jeroen 《Multimedia Tools and Applications》2018,77(1):597-629
Multimedia Tools and Applications - Recording videos with smartphones at large-scale events such as concerts and festivals is very common nowadays. These videos register the atmosphere of the event... 相似文献
115.
Shan Nan Xu-dong Lu Pieter Van Gorp Hendrikus H. M. Korsten Richard Vdovjak Uzay Kaymak Hui-long Duan 《浙江大学学报:C卷英文版》2018,19(7):937-946
In recent years, it has been demonstrated that checklists can improve patient safety significantly. To facilitate the effective use of checklists in daily practice, both the medical community and the informatics community propose to implement checklists in dynamic checklist applications that can be integrated into the clinical workflow and that is specific to the patient context. However, it is difficult to develop such applications because they are tightly intertwined with the content of specific checklists. We propose a platform that enables access to dynamic checklist applications by configuring the infrastructures provided in the platform. Then, the applications can be developed without time-consuming programming work. We define a number of design criteria regarding point of care and clinical processes by analyzing the existing checklist applications and the lessons learned from implementations. Then, by applying rule-based clinical decision support and workflow management technologies, we design technical mechanisms to satisfy the design criteria. A dynamic checklist application platform is designed based on these mechanisms. Finally, we build a platform in various design cycle iterations, driven by multiple clinical cases. By applying the platform, we develop nine comprehensive dynamic checklist applications with 242 dynamic checklists. The results demonstrate both the feasibility and the overall generic nature of the proposed approach. We propose a novel platform for configuring dynamic checklist applications. This platform satisfies the general requirements and can be easily configured to satisfy different scenarios in which safety checklists are used. 相似文献
116.
Yao Zhang Catherine A. Davy Gregory Tricot Cyrille Albert‐Mercier Natacha Henry Pieter Bertier Frédéric Cazaux Denis Damidot Xavier Bourbon 《Journal of the American Ceramic Society》2017,100(9):4131-4152
This research investigates the long‐term shrinkage and Relative Mass Loss (RML) of mature Portland concretes (pure CEMI and blended CEMV/A), at temperatures of 20°C and 80°C. When placed at 80°C and at relative humidities (RH) below 50‐60%, concrete shrinkage increases with very slow stabilization kinetics by several hundreds of μm/m, while RML remains of about 0.2%. The origins of this continued shrinkage, simultaneously with limited RML, are investigated through the changes in (i) the pore structure of the concretes (by Mercury Intrusion Porosimetry and nitrogen adsorption) and in (ii) their solid phases (by TGA/DTA, FTIR spectroscopy coupled to DVS, quantitative X‐Ray Diffraction by Rietveld analysis, and 29Si and 27Al MAS NMR). While the pore structure coarsens during continued shrinkage, several phase transformations occur, namely ettringite decomposition and changes in the silicate chain length of the C–A–S–H. While these structural changes are documented, their relationship with shrinkage/RML and to the pore structure is novel. 相似文献
117.
Stability of rare‐earth‐doped spherical yttria‐stabilized zirconia synthesized by ultrasonic spray pyrolysis
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Nazia Nafsin Hui Li Elisabeth W. Leib Tobias Vossmeyer Pieter Stroeve Ricardo H. R. Castro 《Journal of the American Ceramic Society》2017,100(10):4425-4434
Phase stability is one of the crucial requirements for any material that can be used at elevated temperature applications such as thermal barrier coating (TBC). The most traditional TBC material, partially stabilized zirconia, limits the operating temperature due to its phase transformation. Conversely, the low thermal conductivity of fully stabilized zirconia (YSZ) may enable effective reduction in the surface temperature on the coated component, while avoiding deleterious phase transitions, although still being subjected to sintering and grain growth. It has been reported that addition of rare‐earths as dopants to YSZ can significantly increase resistance to grain growth at high temperature. Keeping this under consideration, this work investigates the role of rare‐earths (lanthanum and gadolinium) in increasing thermal stability of YSZ microspheres, the building blocks for high‐temperature photonics for reflective TBC. The spheres were produced by ultrasonic spray pyrolysis, and the doping led to significant improvement of stability by significant inhibition of grain growth. While the individual dopants showed significant growth and sintering inhibition up to 900°C, co‐doping with 4% (in mol) of each (Gd and La) led to coarsening resistance up to 1000°C for 3 hours, when particles retained reasonable spherical features with nanometric crystallite sizes. 相似文献
118.
David J. Van Cauwenberge Laurien A. Vandewalle Pieter A. Reyniers Kevin M. Van Geem Guy B. Marin Jens Floré 《American Institute of Chemical Engineers》2017,63(5):1715-1726
Streamwise periodic boundary conditions (SPBCs) have been successful in reducing the computational cost of simulating high aspect ratio processes. Extending beyond the classic assumptions of constant property flows, a novel approach incorporating non‐equilibrium kinetics was developed and implemented for the simulation of an industrial propane steam cracker. Comparison with non‐periodic benchmarks provided validation as relative errors on the main product yields were consistently below 1% for different reactor configurations. A further order‐of‐magnitude reduction of the radial errors on product concentrations was obtained via an intuitive correction method based on the concept of local fluid age. The computational speedup achieved through application of SPBCs was a factor 16–250 compared to the non‐periodic simulations. The presented methodology thus serves as a quick screening tool for the development of novel reactor designs and unlocks the potential for using more elaborate kinetic models or a more fundamental approach toward turbulence modeling. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1715–1726, 2017 相似文献
119.
Ye Xu Pieter Harpe Trond Ytterdal 《Analog Integrated Circuits and Signal Processing》2017,90(1):17-27
Area and power consumption are two main concerns for the electronics towards the digitalization of in-probe 3D ultrasound imaging systems. This work presents a 10-bit 30 MS/s successive approximation register analog-to-digital converter, which achieves good area efficiency as well as power efficiency, by using a symmetrical MSB-capacitor-split capacitor array with customized small-value finger capacitors. Moreover, simplified dynamic digital logic and a dynamic comparator have been designed. Fabricated in a 65 nm CMOS technology, the core circuit only occupies 0.016 mm2. The ADC achieves a signal-to-noise ratio of 52.2 dB, and consumes 61.3 μW at 30 MS/s from a 1 V supply voltage, resulting in a figure of merit (FoM) of 6.2 fJ/conversion-step. The FoM defined by including the area is 0.1 mm2 fJ/conversion-step. 相似文献
120.
A new model for predicting the frequency of extreme river levels is proposed which encapsulates physical knowledge about river dynamics. The central idea is the use of continuous time stochastic processes that use hydrological equations and ergodic theory to model extreme events, rather than relying on statistical fits of classical models to local maximum data. A simple example shows how changes in discharge characteristics change the extreme river level frequencies. Solutions are provided for special cases, and directions for more general techniques are provided. 相似文献