Experimental and numerical investigation of a phase change material: Thermal-energy storage and release

The application of phase change materials (PCMs) for solar thermal-energy storage capacities has received considerable attention in recent years due to their large storage capacity and isothermal nature of the storage process. This study deals with the comparison of numerical and experimental results for a PCM conditioned in a parallelepipedic polyefin envelope to be used in passive solar walls. The experimental results were obtained by use of a genuine set-up involving heat flux sensors and thermocouples mounted on two vertical aluminium exchanger plates squeezing the samples. Numerical predictions were obtained with a custom one-dimensional Fortran code and a two-dimensional use of Fluent. Both methods showed a very good agreement with experimental observations for the melting process (?5%). However during solidification, both numerical codes failed to predict the phase change process accurately, the maximal relative error was as high as 57% (with an average of 8%).     

用于精确焊接的智能视觉系统

通过与其它传感技术的对比,简要分析了激光视觉在焊接生产中得到成功应用的原因。分析了早期激光视觉系统的特征和当时面临的挑战。介绍了Servo-Robot激光视觉的关键技术和已取得的显著进步,阐述了集成激光视觉的移动式便携焊接机器人和激光视觉在焊缝质量检测中的应用。展望了激光视觉系统的未来和智能视觉在提高机器人性能方面发展的显著进步,包括改进机器人人工示教、离线编程及视觉辅助机器人示教。     

Modelling of cooking-cooling processes for meat and poultry products

Traditional cooking‐cooling of processed meat and poultry products is industrially carried out in smokehouses or autoclaves. A mathematical model was developed to simulate these operations. Equations, describing heat transfer and thermal destruction of micro‐organisms and quality characteristics, were solved numerically. The model was validated experimentally for heat transfer and energy consumption and was used to perform a sensitivity analysis. Input variables were: process time (PT), smokehouse temperature (T_SH), bologna size (diameter, D and height, H), surface heat transfer coefficients (h_heat and h_cool), product thermal diffusivity (α_heat and α_cool). Output variables were: product core temperature (T_c), core and volume‐average lethality (P_cm and P_vm) and cook (C_c and C_v) values as well as surface (Q_s) and volume‐average (Q_v) quality retention, total specific energy consumption (En) and energy efficiency (Ce). Multiple linear regression models were developed to predict C_c and C_v from five inputs and used to obtain acceptable deviation ranges.     

Integration of diamond in fully-depleted silicon-on-insulator technology as buried insulator: A theoretical analysis

We examine here by electro-thermal simulation tools (SILVACO's Atlas) a configuration of Silicon-On-Insulator substrate for Fully-Depleted MOSFET architectures, incorporating diamond as buried insulator, and compare it with traditional silicon dioxide BOX for the future technological nodes of the ITRS (90 nm and below). Our aim is to give major trends to be followed in order to optimize diamond integration from electrical and thermal points of view, constraints that must be kept in mind in parallel with the technological work on thin diamond films. In this theoretical study, we perform a benchmarking between SiO₂ and diamond BOX. We first point out that the BOX thickness should not be more than few hundred nanometers to maintain electrical performances. From thermal point of view, we demonstrate that the replacement of 100 nm thick buried oxide by a 100 nm thick diamond layer can lead to about 50% reduction of the temperature when only 33% decrease can be obtained with Ultra Thin SiO₂ BOX (20 nm). Furthermore, thick diamond BOX avoids the parasitic capacitances issue that reduces Ultra Thin BOX devices working frequency.     

Membrane performance in combined processes including ozonation or advanced oxidation, powdered activated carbon and coagulation — Investigations in pilot scale

In Luxembourg the largest drinking water production plant treating reservoir water with conventional technology including ozonation is in operation since 1969. Its maximum capacity is 64,000 m³/d. After 40 years of operation the need for both modernizing and extension of capacity to 100,000 m³/d emerged. Nowadays, due to new developments in technology and research it is possible to assess the water treatment processes more effectively with regard to current and future requirements. Against this background, membrane processes combined with conventional and advanced processes were identified as potential option and long term pilot-scale tests were started in June 2008. Different treatment process schemes all including membranes are investigated in a one year pilot plant period. Various treatment steps such as different pre- and post-treatment steps, various membranes and membrane materials and also conventional treatment steps are compared and assessed.     

Virtual reality for cultural landscape visualization

Although land managers and policy-makers generally have a good experience of what result can be expected from their decisions, they are often faced with difficulty when trying to communicate the visual impact of a management option to stakeholders, particularly when the landscape exhibits a high cultural value. Three-dimensional visualization of the landscape is often used for communicating with the stakeholders. A challenge in participatory methods for integrated assessment and policy planning is to view future changes in land use, according to scenarios. A 3-D landscape visualization component, SLE (“Seamless Landscape Explorer”), has been developed, which is launched after a scenario simulation to allow for exploration of landscape changes. Pressures causing such changes are translated into changes in the spatial configuration of the landscape. The different types of land-use are visualized thanks to a library of detailed textures, and vegetation can be added. This has been applied to a study of four scenarios in the French Mediterranean region, which were set up as part of a participatory process for discussing the planning of the regional peri-urban and agricultural policy, in an area dominated by the typical culturally sensitive Mediterranean matorral, (“garrigue” shrubland) surrounding the Pic Saint-Loup mountain. Examples of visualization are shown and discussed here.     

Aquifex aeolicus membrane hydrogenase for hydrogen biooxidation: Role of lipids and physiological partners in enzyme stability and activity

Hydrogenase I from the hyperthermophilic bacterium Aquifex aeolicus is a good candidate for biotechnological devices thanks to its ability to oxidize hydrogen at high temperature, even in the presence of oxygen and CO. In order to enhance the enzyme stability and the catalytic efficiency, we investigated the hydrogen oxidation process with hydrogenase I embedded in a physiological-like environment. Hydrogenase I partners in the metabolic chain, namely membrane quinone and cytochrome b, were purified and fully characterized. The complex hydrogenase I–cytochrome b was inserted into liposomes. Surface Plasmon Resonance revealed that quinone took part in the stabilization of the complex. By use of molecular modelization and electrochemistry analysis, enzyme stability has been demonstrated to be stronger and enzymatic efficiency to be five times higher when hydrogenase is embedded into the liposomes. This result raises the possibility of using hydrogenases as biocatalysts in fuel cells.     

3-D deformable image registration: a topology preservation scheme based on hierarchical deformation models and interval analysis optimization.

This paper deals with topology preservation in three-dimensional (3-D) deformable image registration. This work is a nontrivial extension of, which addresses the case of two-dimensional (2-D) topology preserving mappings. In both cases, the deformation map is modeled as a hierarchical displacement field, decomposed on a multiresolution B-spline basis. Topology preservation is enforced by controlling the Jacobian of the transformation. Finding the optimal displacement parameters amounts to solving a constrained optimization problem: The residual energy between the target image and the deformed source image is minimized under constraints on the Jacobian. Unlike the 2-D case, in which simple linear constraints are derived, the 3-D B-spline-based deformable mapping yields a difficult (until now, unsolved) optimization problem. In this paper, we tackle the problem by resorting to interval analysis optimization techniques. Care is taken to keep the computational burden as low as possible. Results on multipatient 3-D MRI registration illustrate the ability of the method to preserve topology on the continuous image domain.