21 research outputs found

    The risk of liquid wood degradation under the influence of marine factors

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    A case study was performed, concerning the behavior and degradation of a polymeric biocomposite material – “liquid wood”. This material is biodegradable and it is obtained from renewable resources. Three presentation forms – Arbofill Fichte, Arboform F45 and Arboblend V2, were subjected to the action of external factors present in a marine environment. The results pertaining to the change in the physico – chemical properties of “liquid wood” when subjected to the action of seawater and seawater microorganisms, with significant – but nevertheless positive – consequences upon the environment. The material exhibits good performance after the surface and mass stabilization – due to water, C, Na, Cl and O absorption. As such – due to the emergence of a protective organic biofilm – growth of microorganisms significantly decreases and electric conductivity increases. This case study may be viewed as a starting point for subsequent studies of “liquid wood”

    Then and now: construction management practices in Romania and the Netherlands

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    The purpose of this study is to compare and contrast construction management practices in Romania and the Netherlands by focusing on the institutional context, used building systems, and labour organisation from 1945 until nowadays. Social, economic and historical aspects have also been taken into account, in order to provide useful insight on two countries that represent two ‘worlds’ (Western Europe vs. Eastern Europe), with different building philosophies. Data collection and analysis were based on interviews with experts in the field of civil engineering, correlated with various publications from both past and present times. The significance of this study lies in the fact that, although similar studies have been performed before, to the authors’ knowledge there is little information about construction management in pre-1989 Eastern Bloc. This study compares an Eastern European country (Romania) with data from the construction management in pre-1989 Western European country (the Netherlands)

    Developing a TRL-oriented roadmap for the adoption of biocomposite materials in the construction industry

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    The construction industry is a major contributor to environmental pollution. The effect of the construction industry on the environment may be mitigated using eco-friendly construction materials, such as biocomposites. Once developed, biocomposites may offer a viable alternative to the current materials in use. However, biocomposites are lagging in terms of adoption and eventual use in the construction industry. This article provides insights into the steps for biocomposites to become a product that is ready to use by the construction industry in a structural role. The development and the adoption of such a material is tackled with the use of two concepts, i.e., technology readiness level and roadmapping, and explored in a case study on the “liquid wood”. Furthermore, interviews in the construction industry are carried out to identify the industry’s take on biocomposites. A customized roadmap, which underlines a mostly nontechnical perspective concerning this material, has emerged. Additionally, the adoption and diffusion issues that the “liquid wood” may encounter are outlined and complemented with further recommendations

    “Holographic Implementations” in the Complex Fluid Dynamics through a Fractal Paradigm

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    Assimilating a complex fluid with a fractal object, non-differentiable behaviors in its dynamics are analyzed. Complex fluid dynamics in the form of hydrodynamic-type fractal regimes imply “holographic implementations” through velocity fields at non-differentiable scale resolution, via fractal solitons, fractal solitons–fractal kinks, and fractal minimal vortices. Complex fluid dynamics in the form of Schrödinger type fractal regimes imply “holographic implementations”, through the formalism of Airy functions of fractal type. Then, the in-phase coherence of the dynamics of the complex fluid structural units induces various operational procedures in the description of such dynamics: special cubics with SL(2R)-type group invariance, special differential geometry of Riemann type associated to such cubics, special apolar transport of cubics, special harmonic mapping principle, etc. In such a manner, a possible scenario toward chaos (a period-doubling scenario), without concluding in chaos (nonmanifest chaos), can be mimed

    Analytical Study Regarding the Seismic Response of a Moment-Resisting (MR) Reinforced Concrete (RC) Frame System with Reduced Cross Sections of the RC Beams

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    In the last few decades, a series of earthquakes were recorded which pointed out several deficiencies regarding the ductile seismic response of MR RC frame structures. Thus, the research problem centres around the failure mechanisms registered by the structures, which differ from the general notions of seismic response commonly found in current design standards and norms regarding seismic actions. In these conditions, in the present paper—by using comparative methods—the analytical validation of the solution of plastic hinge concentration and seismic energy dissipation in the marginal beam areas is proposed. Therefore, the RC beam sections were reduced (weakened) in the marginal areas which exhibit a plastic deformation potential, as well as in the corner areas of concrete slabs with vertical rectangular holes. The significant outcomes of this research imply the partial “guiding” of plastic hinges in the zones adjacent to beam ends. Furthermore, a reduction of both the negative effects of horizontal rigidization of the beams and the cracking and plastic deformation effects of beam-column frame joints was observed. With these technical implications, a complex mechanism of plastic deformation of MR RC frame models is registered in which all lateral elements (including RC columns) participate in the dissipation of seismic energy, without the occurrence of the “weak storey” mechanism for any of the analytical RC frame models. Furthermore, it is possible to observe the partial formation of the global plastic mechanism “Strong Columns—Weak Beams” (SCWB) for some of the structural models. Finally, the analytically studied innovative element regarding the improvement of the seismic response of pure MR RC frame structures is successfully validated

    Toward Interactions through Information in a Multifractal Paradigm

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    In a multifractal paradigm of motion, Shannon’s information functionality of a minimization principle induces multifractal–type Newtonian behaviors. The analysis of these behaviors through motion geodesics shows the fact that the center of the Newtonian-type multifractal force is different from the center of the multifractal trajectory. The measure of this difference is given by the eccentricity, which depends on the initial conditions. In such a context, the eccentricities’ geometry becomes, through the Cayley–Klein metric principle, the Lobachevsky plane geometry. Then, harmonic mappings between the usual space and the Lobachevsky plane in a Poincaré metric can become operational, a situation in which the Ernst potential of general relativity acquires a classical nature. Moreover, the Newtonian-type multifractal dynamics, perceived and described in a multifractal paradigm of motion, becomes a local manifestation of the gravitational field of general relativity

    On The Heat Transfer Of Holographic Type In Nanostructures

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    Assimilating any nanostructure with a fractal, in the most general Mandelbrot's sense, non - differentiable behaviors in their dynamics on the heat transfer phenomena are analyzed. As such, nanostructure dynamics on the heat transfer in the form of Schrodinger - type various regimes imply "holographic implementation" of the thermal fields through groupal invariance of SL(2R) type. Then, by means of previous groupal invariance as synchronization group between any nanostructure entities, both the phases and the amplitudes of the entities are affected from a homographic perspective. In a special case of synchronization of nanostructure entities, given by Riccati type gauge, period doubling, damping oscillations, self - modulation and chaotic regimes emerge as natural behaviors in the nanostructure dynamics of the heat transfer processes. The present model can also be applied to a large class of nanostructures (i.e. polymeric biocomposites, "liquid wood", temperature - depending drug release systems etc.)

    Numerical Study Regarding the Seismic Response of a Moment-Resisting (MR) Reinforced Concrete (RC) Frame Structure with Reduced Cross-Sections of the RC Slabs

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    In the first part of the current study, the effectiveness of the transversal cross-section reduction method for RC beams in marginal areas (by means of mechanical drilling) was validated. The said method “encourages” the formation of plastic hinges at the beam ends and, at the same time, allows for taking into account the bending stiffness of RC slabs, which is exerted upon the RC beams. In these conditions, the second part of the current research study (i.e., the current manuscript) highlights the real mode of reducing the lateral stiffness of the slabs upon the RC beams. These elements form a common body, together with the beam–column frame node. The same method as in the first part of the study—“weakening” the plates in the corner area through vertical drilling, without affecting the integrity of the reinforcing elements—was used. The analytical MR RC frame model, studied by means of the comparative method, highlights the efficiency of the transversal cross-section reduction method for RC slabs. Basically, the directing of the plastic deformations from the weakened slab areas towards the marginal areas of the reinforced concrete beams takes place. The beams rotate as far as the weakened slab areas allow its plastic deformation, thus being possible to observe the partial conservation effect of the beam–column frame joint. Furthermore, for the analytical model with the maximum number of vertical holes in the corner areas of the concrete plate, minimal plastic deformations are recorded for the marginal areas of the concrete columns. A partial conservation of the formation mechanism of the “beam-slab-frame node” common rigid block is also noted. Consequently, the dissipation of the seismic energy is made in a partially controlled and directed manner, in the “desired” areas, according to the “Strong Columns—Weak Beams” (SCWB) ductile mechanism of the lateral behavior to seismic actions for reinforced concrete frame structures. The mechanism is specified in current design norms for RC frame systems. The effectiveness of the method for reducing the transversal section of the RC plates in the corner areas by means of transversal drilling is highlighted and validated from the perspective of the local and global ductile seismic response of reinforced concrete frame structures. A significant reduction in the bending stiffness of the slabs upon the beams and a real development of the plastic hinges in the marginal areas of the beams (together with partial implications and plastic deformations) were observed

    Complex System Dynamics Through A Fractal Paradigm

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    Assimilating the complex with a fractal, non - differentiable behaviors in their dynamics are analyzed through a fractal paradigm. It results that complex system dynamics in the framework of hydrodynamic - type fractal regimes imply "holographic implementation" of the velocity fields at non - differentiable scale resolution, by means of fractal solitons, fractal solitons - fractal kinks and fractal minimal vortices. These vortices become turbulence sources in complex systems dynamics at non - differentiable scale resolutions
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