Stochastic Simulation of Mould Growth Performance of Wood-Frame Building Envelopes under Climate Change: Risk Assessment and Error Estimation

Previous studies have shown that the effects of climate change on building structures will increase the mould growth risk of the wood-frame building envelope in many circumstances. This risk can be controlled by wind-driven rain deflection, improving water tightness of the exterior facade, and improving cladding ventilation. However, the effectiveness of these risk mitigation strategies are subject to various uncertainties, such as the uncertainties of wall component properties and micro-climatic conditions. The objective of this paper is to apply stochastic hygrothermal simulation to evaluate the mould growth risk of a brick veneer-clad wood-frame wall with a drainage cavity under historical and future climatic conditions of Ottawa, a Canadian city located in a cold climate zone. An extensive literature review was conducted to quantify the range of stochastic variables including rain deposition factor, rain leakage moisture source, cladding ventilation rate and material properties of brick. The randomised Sobol sequence-based sampling method, one of the Randomized Quasi-Monte Carlo (RQMC) methods, was applied for risk assessment and error estimation. It was found that, under the climatic condition of Ottawa, limiting the amount of wind-driven rain to which walls are subjected is a more robust mitigation measure than improving cladding ventilation in controlling mould growth risk, the improving of water tightness of exterior façade is not as robust as wind-driven rain deflection and cladding ventilation, however, the reduction of rainwater penetration can reduce the mould growth risk at different levels of rain deposition factor and cladding ventilation rate.

Advances in Reconfigurable Vectorial Thrusters for Adaptive Underwater Robots

Manoeuvrability is one of the essential keys in the development of improved autonomous underwater vehicles for challenging missions. In the last years, more researches were dedicated to the development of new hulls shapes and thrusters to assure more manoeuvrability. The present review explores various enabling technologies used to implement the vectorial thrusters (VT), based on water-jet or propellers. The proposals are analysed in terms of added degrees of freedom, mechanisms, number of necessary actuators, water-tightness, electromagnetomechanical complexity, feasibility, etc. The usage of magnetic coupling thrusters (conventional or reconfigurable) is analysed in details since they can assure the development of competitive full waterproof reconfigurable thrusters, which is a frictionless, flexible, safe, and low-maintenance solution. The current limitations (as for instance the use of non conductive hull) are discussed and ideas are proposed for the improvement of this new generation of underwater thrusters, as extending the magnetic coupling usage to obtain a fully contactless vector thrust transmission.

Rock Slope Stability and Water tightness Assessment of Arjo Didesa Dam site, Western Ethiopia

Arjo Didesa dam is an earth and rock fill dam which is under construction on the Didesa River in western Ethiopia. However, the dam encountered engineering geological problems that affected the water tightness and slope stability of the dam abutments and reservoir area. To solve these problems, different methods such as discontinuity survey, packer test, sampling and laboratory tests were applied to evaluate the engineering geological conditions of materials along the dam abutments and reservoir area on slope stability and water tightness. Slope stability analyses were performed by kinematic, limit equilibrium and finite element methods using laboratory and in-situ tests. Kinematic analyses revealed that both the left abutment slope 1(LAS1) and the right abutment slope 1(RAS1) sections were unstable for planar mode of failures. Further stability analyses using deterministic methods indicated that both sections were unstable only during saturated conditions. Similarly, stability analysis using limit equilibrium and finite element method revealed that both the left abutment slope 2(LAS2) and the right abutment slope 2(RAS2) sections were unstable under saturated conditions. This study also analyzed the permeability of soils and rock masses and the result showed that the permeability values range from 2.693*10− 7cm/s − 6.687*10− 5cm/s and 3.19*10− 5cm/s − 1.3*10+ 1cm/s for soils and rock masses respectively. Integration of surface hydraulic conductivity and subsurface packer permeability tests showed the presence of potential leakage through the dam abutments. Remedial measures such as rock bolts, anchors and shotcrete for slope stabilization and grouting and clay blanketing are recommended to control this leakage.

Determination of deformations and self-stress in concrete on stress cement

The article considers using a single-layer reinforced ten-centimeter layer of concrete on stress cement instead of the traditional multilayer construction of waterproofing bridges. The proposed design will ensure the water tightness of the bridge deck due to the self-stress in the concrete on the stressing cement, the value of which is proportional to the deformations of concrete and reinforcement. Concrete deformations are uneven over the layer height, and the resulting stress in concrete depends on the reinforcement coefficient. Experiments were carried out to determine the deformations of concrete and the magnitude of self-stress, which provides the waterproofing properties of a bridge deck made of concrete on stress cement. The study of the self-tension process, identifying those factors on which its value depends, is necessary for a correct understanding of the physics of the self-tension process. In addition, it is necessary to check the applicability of various proposed empirical dependences for concrete on stress cement of the composition under consideration.

Results of the implementation of work on the creation of virtual test benches for testing the digital twin of the bus

The results of the implementation of work in the field of creating virtual test benches for testing digital twins of products in the automotive industry are presented. The results of the implementation of virtual benches for assessing the water tightness and drainage of bus bodies are specifically considered. The structure of the virtual bench for assessing the sound absorption of materials in the alpha chamber is given. The results of the development of the concept of a virtual test bench for the bus electrical equipment simulation are presented.