Topology optimization for design-dependent hydrostatic pressure loading via the level-set method

A few level-set topology optimization (LSTO) methods have been proposed to address complex fluid-structure interaction. Most of them did not explore benchmark fluid pressure loading problems and some of their solutions are inconsistent with those obtained via density-based and binary topology optimization methods. This paper presents a LSTO strategy for design-dependent pressure. It employs a fluid field governed by Laplace’s equation to compute hydrostatic fluid pressure fields that are loading linear elastic structures. Compliance minimization of these structures is carried out considering the design-dependency of the pressure load with moving boundaries. The Ersatz material approach with fixed grid is applied together with work equivalent load integration. Shape sensitivities are used. Numerical results show smooth convergence and good agreement with the solutions obtained by other topology optimization methods

Exploring the Simultaneous Effect of Total Ion Concentration and K:Ca:Mg Ratio of the Nutrient Solution on the Growth and Nutritional Value of Hydroponically Grown Cichorium spinosum L.

Nutrient-efficient plants and agricultural systems could tackle issues resulting from conventional agriculture. Spiny chicory (Cichorium spinosum L.), a very adaptive, wild edible vegetable, is gaining commercial interest as a functional food. Floating-raft hydroponics is a method commonly used for the commercial cultivation of leafy vegetables due to numerous advantages compared to soil cultivation. In this paper, the simultaneous effects of different potassium, calcium and magnesium ratios and different electrical conductivity (EC) levels on the growth and mineral composition of hydroponically grown C. spinosum were investigated. Four nutrient solutions (NS) were compared, two NS with low EC (L, 2.4 dS/m) and two with high EC (H, 3.6 dS/m) with K:Ca:Mg ratios of either 50:40:10 or 40:50:10. The results showed no interactions between the two factors. No significant effects were observed on the fresh and dry weight, leaf number and leaf area. High EC levels increased the K content and decreased the Mn and Zn content in the leaf tissues. The 40:50:10 ratio led to increased Ca content in plant tissues. The Nitrate-N was only affected by the EC level and was increased under H conditions, whereas the total-N was not affected

The UK and German low-carbon industry transitions from a sectoral innovation and system failures perspective

Industrial processes are associated with high amounts of energy consumed and greenhouse gases emitted, stressing the urgent need for low-carbon sectoral transitions. This research reviews the energy-intensive iron and steel, cement and chemicals industries of Germany and the United Kingdom, two major emitting countries with significant activity, yet with different recent orientation. Our socio-technical analysis, based on the Sectoral Innovation Systems and the Systems Failure framework, aims to capture existing and potential drivers of or barriers to diffusion of sustainable industrial technologies and extract implications for policy. Results indicate that actor structures and inconsistent policies have limited low-carbon innovation. A critical factor for the successful decarbonisation of German industry lies in overcoming lobbying and resistance to technological innovation caused by strong networks. By contrast, a key to UK industrial decarbonisation is to drive innovation and investment in the context of an industry in decline and in light of Brexit-related uncertainty

Strategies, methods and tools for managing nanorisks in construction

This paper presents a general overview of the work carried out by European project SCAFFOLD (GA 280535) during its 30 months of life, with special emphasis on risk management component. The research conducted by SCAFFOLD is focused on the European construction sector and considers 5 types of nanomaterials (TiO2, SiO2, carbon nanofibres, cellulose nanofibers and nanoclays), 6 construction applications (Depollutant mortars, selfcompacting concretes, coatings, self-cleaning coatings, fire resistant panels and insulation materials) and 26 exposure scenarios, including lab, pilot and industrial scales. The document focuses on the structure, content and operation modes of the Risk Management Toolkit developed by the project to facilitate the implementation of "nano-management" in construction companies. The tool deploys and integrated approach OHSAS 18001 - ISO 31000 and is currently being validated on 5 industrial case studies.Research carried out by project SCAFFOLD was made possible thanks to funding from the European Commission, through the Seventh Framework Programme (GA 280535

P21-PARP-1 pathway is involved in cigarette smoke-induced lung DNA damage and cellular senescence

Persistent DNA damage triggers cellular senescence, which may play an important role in the pathogenesis of cigarette smoke (CS)-induced lung diseases. Both p21(CDKN1A) (p21) and poly(ADP-ribose) polymerase-1 (PARP-1) are involved in DNA damage and repair. However, the role of p21-PARP-1 axis in regulating CS-induced lung DNA damage and cellular senescence remains unknown. We hypothesized that CS causes DNA damage and cellular senescence through a p21-PARP-1 axis. To test this hypothesis, we determined the levels of γH2AX (a marker for DNA double-strand breaks) as well as non-homologous end joining proteins (Ku70 and Ku80) in lungs of mice exposed to CS. We found that the level of γH2AX was increased, whereas the level of Ku70 was reduced in lungs of CS-exposed mice. Furthermore, p21 deletion reduced the level of γH2AX, but augmented the levels of Ku70, Ku80, and PAR in lungs by CS. Administration of PARP-1 inhibitor 3-aminobenzamide increased CS-induced DNA damage, but lowered the levels of Ku70 and Ku80, in lungs of p21 knockout mice. Moreover, 3-aminobenzamide increased senescence-associated β-galactosidase activity, but decreased the expression of proliferating cell nuclear antigen in mouse lungs in response to CS. Interestingly, 3-aminobenzamide treatment had no effect on neutrophil influx into bronchoalveolar lavage fluid by CS. These results demonstrate that the p21-PARP-1 pathway is involved in CS-induced DNA damage and cellular senescence

Topology optimization for heat flow manipulation

The aim of this thesis is to explore the use of topology optimization in designing materials for heat flow manipulation. Specifically shielding, concentrating or even inverting the heat current was examined. The possibility to scale the problem from macro- to nano-dimensions by using topology optimization for nanoscale heat conduction was also investigated. An optimization tool for heat flux shielding, focusing and reversal is presented. Different objective functions were defined in order to shield, focus or reverse heat flow within an area surrounded by a composite material with anisotropic thermal conductivity. The composite material under consideration consisted of thermally conductive elliptical inclusions embedded in a poor conductive matrix. The effective thermal conductivity was defined based on the equivalent inclusion theory. The dependence of the anisotropic thermal conductivity on the angle that the inclusions make with the imposed gradient was then approximated via a coordinate transformation. The material distribution method for topology optimization was then used to find the optimum angle distribution of the inclusion angle for heat shielding, focusing and reversal. The use of topology optimization for heat conduction in nanostructures was also investigated. At such small length scales the classical Fourier model for heat conduction is no longer applicable. As the dimensions of a structure become comparable to the mean free path of heat carriers (electrons or phonons), heat transfer changes from diffusive to semi-ballistic. Length scale effects such as scattering of the heat carriers with other phonons, material interfaces and boundaries become important. To take into account all this length effects, a more accurate model is given by the kinetic theory. Specifically the Boltzmann Transport Equation (BTE) for phonon transport was used to model the transfer of heat. To solve the BTE, a deterministic discrete ordinates method (DOM) was used in combination with the finite element method. Using COMSOL Multiphysics, the Boltzmann transport equation was successfully coupled with the MMA optimization algorithm and a Helmholtz PDE based filter. The method was implemented for the optimization of a simple system in order to illustrate its applicability.Mechanical, Maritime and Materials EngineeringMaterials Science and Engineerin

Level set topology optimization for fluid-structure interactions

In this work a level set topology optimization (LSTO) method is developed in combination with a nodally integrated reproducing kernel particle method (RKPM) for solving fluid-structure interaction problems (FSI). FSI falls into a specific class of topology optimization problems known as design-depended. In this class the direction, magnitude and position of the loads depend on the structure itself. Thus, the main challenge lies in tracking the interface to correctly apply the loads and coupling conditions. The simplest class of design-dependent loading problems considering only hydrostatic pressure is addressed here, with the aim of extending the same methodology to viscous flows in the near future. The freedom RKPM offers to place particles anywhere in the domain in combination with the implicit boundary representation given by the level set method, provides an effective framework to handle the dendency of loading by moving the particles on the pressure boundary without the need of remeshing or special numerical treatments. Benchmarking examples involving both constant and variable pressure loads are solved to illustrate the applicability of the methodology. For the extension to viscous flows, we set up an initial framework that utilizes the modified immersed finite element method (mIFEM) through the opensource software OpenIFEM. With mIFEM the coupled equations can be solved efficiently on a fixed fluid grid, thus avoiding to remesh for the fluid, while the solid on top of the fluid is free to move and deform. Combining LSTO, RKPM and mIFEM, the optimized results obtained for hydrostatic pressure are placed in a viscous flow field to perform a transient analysis. The LSTO defines the geometry of the structure, the solid domain is analyzed using RKPM with the naturally stabilized nodal integration technique (NSNI) and mIFEM is used to solve the coupled equations on a fixed fluid mesh

Immune and genetic mechanisms in COPD: possible targets for therapeutic interventions.

Genetic, immune and environmental interactions are key elements for the development of COPD. Cigarette smoking is considered the primary risk factor initiating inflammatory cascades in genetically susceptible individuals. The "danger signals" elicited by the injured cells of non-specific immunity induce the downstream activation of proinflammatory cascades and antigen-specific adaptive immune responses. The produced oxidative stress further damages the lung leading to acquired genetic changes (histone deacetylation, microsatellite DNA instability, DNA methylation, telomere shortening, miRNA alterations) due to an inefficient DNA repair machinery. On the other hand, augmented apoptosis, impaired efferocytosis and abnormal tissue remodeling contribute to the chronic inflammatory response and tissue destruction in COPD. This review focuses on the role of genetic, epigenetic and immune mechanisms in the development of COPD in order to put forward possible prognostic and therapeutic targets