Lucrari stiintifice

1. FLEXURAL STIFFNESS OF HYBRID WOOD - FIBRE REINFORCED POLYMER COMPOSITES ELEMENTS

I.S. ENȚUC, D.N. ISOPESCU, S.G. MAXINEASA, N. ȚĂRANU, Bulletin of the Transilvania University of Braşov, Vol. 10 (59) Special Issue No. 1 - 2017, Series I: Engineering Sciences

Abstract

An analytical evaluation of hybrid section made of wood and Fibre Reinforced Polymer (FRP) composites which consist of several FRP applying techniques is studied. The main objectives of using FRP and wood to obtain composite elements is for increasing capacity of timber beam. The favourable performances of wood as a building material recommend its utilisation in the various and complex timber structures with large spans having significant deflection and requirements of the rigidity. The increasing of wood elements stiffness can be reached by applying FRP reinforcement. The flexural stiffness of the hybrid elements made of wood products and Carbon and Glass fibre reinforced polymer composite strips and bars is analysed in the paper.

Key words: flexural stiffness, hybrid section, wood, FRP composites.

2. Thermal Analysis of a Structural Solution for Sustainable, Modular and Prefabricated Buildings

D N Isopescu, S G Maxineasa, O Neculai, IOP Conf. Ser.: Mater. Sci. Eng. 209 012076, 2017

Abstract

In the construction field, the design principles for an efficient and operational use of buildings and a minimal impact on the environment are essential aspects of sustainable development. In this regard, several aspects must be taken into consideration, such as: durability, easy maintenance, flexibility in interior design, and reduced energy consumption. Decreasing energy consumption in buildings during the service life (heating / cooling / drinking water / electricity) can mean lower costs, but also a lower impact on the environment. The paper presents the thermal analysis for a GF+1F height structure, consisting of several identical, adjacent and / or overlapped metallic cubic modules. The spaces inside this cubes ensemble solve the functionality of a family home building. The good carrying capacity, the rapidity of execution, the superior degree of thermal insulation and the minimum losses of material in execution were the main advantages provided by this structural solution. Regarding the thermal comfort for the users of this constructive system, the thermal analysis showed that the internal temperatures are constant and uniform, without cold surfaces or temperature fluctuations. In addition, humidity is controlled and there is no risk of condensation.

3. THE NECESSITY OF ENVIRONMENTALLY FRIENDLY BUILDINGS IN THE CITY OF IAŞI

SEBASTIAN GEORGE MAXINEASA, DANIEL FLORIN MAXIM1, CLAUDIU COSMIN ŢÂŞNEI, DORINA NICOLINA ISOPESCU, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, Volumul 64 (68), Numărul 3, 2018, Secţia CONSTRUCŢII. ARHITECTURĂ

Abstract

The tremendous amounts of materials consumed, the high volume of equivalent carbon dioxide released during the processes specific to the built environment, its significant contribution to every national economy, and the perpetual social influence it exerts represent the main arguments that are transforming the construction sector into one of the most important factors in achieving the primary dimensions of sustainability at the global scale. It is well known that this industry exerts a significant ecological impact; therefore, civil engineering specialists should promote and use solutions that reduce the impact of the built environment over the natural one. Taking into account the above, the goal of the present paper is to underline the necessity of building new constructions in the city of Iaşi by taking into consideration the sustainability concept and analysing and understanding the issues specific to the local context.

Keywords: equivalent carbon dioxide; national economy; social influence; construction sector; sustainability.

4. ENVIRONMENTAL PERFORMANCES OF DIFFERENT CARBON AND GLASS FIBRE REINFORCED POLYMER SHEAR STRENGTHENING SOLUTIONS OF LINEAR REINFORCED CONCRETE ELEMENTS

S.G. MAXINEASA, D.N. ISOPESCU, I.S. ENTUC, N. TARANU, L.M. LUPU, I. HUDISTEANU, Bulletin of the Transilvania University of Brasov • Vol. 11 (60) Special Issue No. 1 – 2018, Series I: Engineering Sciences

Abstract

It is well-known at this point that the construction sector has a significant environmental impact. From the tremendous quantities of raw materials consumed to the impressive amounts of greenhouse gases released into the atmosphere, the built environment is rapidly increasing the negative influence over the Earth’s ecosystem. Therefore, civil engineering specialists should study and promote different solutions characteristic to the construction sector with respect to the environmental dimension of the sustainability concept. One answer to this issue can be represented by the use of fibre reinforced polymer (FRP) materials. The goal of the present paper consists in analysing the opportunity of using different carbon and glass fibre reinforced polymers applied by using the wet lay-up technique for shear strengthening of a linear reinforced concrete (RC) element. By considering the Life Cycle Assessment (LCA) methodology, the study shows that the main environmental advantage of polymeric materials consists in the opportunity of reusing an existing structural element by strengthening it with different FRP solutions. Therefore, composite materials can be regarded as a viable solution for the construction sector’s sustainable development.

Keywords: construction sector, environmental impact, sustainability, FRP, LCA.

5. PERFORMANCES OF THE CONCRETE MASONRY WITH RECYCLED WOOD CHIPS (I)

IOANA SORINA ENŢUC, DORINA NICOLINA ISOPESCU, LAURENŢIU CRISTINEL BAGDASAR, GABRIEL OPRIŞAN, IULIAN DANIEL ZAPODEANU, SEBASTIAN GEORGE MAXINEASA, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, Volumul 64 (68), Numărul 3, 2018, Secţia CONSTRUCŢII. ARHITECTURĂ

Abstract

Nowadays, one of the most important problems is the waste produced by all industries, civil engineering, commerce or consumption of products. In the present study, the authors aimed to obtain a new building material based on wood chips waste produced from different industries. The design material properties are influenced by the wood chips’ percentage in relation to the aggregate volume, embedded in cement. Therefore, it was proposed two mix recipes, materials A and B which contain 50 and 25 percentage of wood chips related to the aggregate volume. Tests were performed for bending (flexural tensile) strengths establishing. These mechanical performances are important properties for the design process of masonry products or structures and for proving their applicability.

Keywords: wood chips; wood waste; mechanical performances; masonry blocks.

6. BEHAVIOUR OF CONCRETE MASONRY UNITS IN COMPRESSION

GABRIEL OPRIŞAN, DORINA NICOLINA ISOPESCU, IULIAN DANIEL ZAPODEANU, IOANA SORINA ENŢUC, OVIDIU BUTNARU, SEBASTIAN GEORGE MAXINEASA, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, Volumul 64 (68), Numărul 3, 2018, Secţia CONSTRUCŢII. ARHITECTURĂ

Abstract

Compressive strength values obtained on concrete masonry units with vertical circular holes in comparisons with compressive strength values obtained on concrete masonry units with circular holes filled with mortar are presented. The experimental program was conducted at the Laboratory of composite Materials in frame of Faculty of Civil Engineering and Building Services, “Ghorghe Asachi” Technical University of Iasi. The authors present a comparison of the compressive strengths. The peak values of principal stresses have been checked by a numerical modelling.

Keywords: concrete masonry units (CMU), vertical circular holes (VCH), compressive strength, finite element analysis (FEA).

7. INFLUENCE OF WATER ABSORPTION BY CAPILLARY ON THE MECHANICAL CHARACTERISTICS OF CONCRETE BRICKS

GABRIEL OPRIŞAN, DORINA NICOLINA ISOPESCU, IULIAN DANIEL, ZAPODEANU, IOANA SORINA ENŢUC, OVIDIU BUTNARU, SEBASTIAN GEORGE MAXINEASA, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, Volumul 64 (68), Numărul 3, 2018, Secţia CONSTRUCŢII. ARHITECTURĂ

Abstract

Technical approval of building materials like concrete bricks requires a series of investigations that relate to dimensions and tolerances, flatness, density, adhesion, compressive strength, water absorption through capillary, thermal conductivity, frost-thaw resistance, and reaction to fire. The authors conducted a series of experimental tests to study the effect of water absorption on compressive strengths and tensile strength from bending on concrete bricks. Thus, comparative graphs were plotted to highlight the differences; the specimen failure modes were also identified.

Keywords: concrete bricks; water absobtion; compressive strength; tensile strength from bending.

8. The impact of green building principles in the sustainable development of the built environment

D N Isopescu, IOP Conf. Ser.: Mater. Sci. Eng. 399 012026, 2018

Abstract

Climate change and the exhaustion of natural resources is a topical issue and represents a "to be solved immediately" goal in the development of built environment. The increasing development of buildings affects the natural environment more than any other industrial process. In Europe, the construction sector is responsible for consuming approximately 50% of the natural resources extracted per year, 40% of the energy produced, 16% of the treated water, and also for producing around 36% of the CO2 emissions and 40-50% of the solid waste. Nowadays, specialists involved in building design have to think, more and more, about the strategies toward high performance buildings, and apply the principles of sustainability to find ways to coexist with the natural conditions, conserving natural resources, preventing land pollution, protecting the environment, and reducing energy consumption. This paper attempts to investigate the results of SWOT analyses on two aspects of the implementation of the principles of eco-innovative design of buildings in Romania: technical regulations for design and execution technologies. Then, analysing cases of green buildings design in the world, and their impact on the environment, it is concluded with the measures to be taken into account for the creation of healthy built areas, by applying the eco-friendly principles in all forms of their manifestation, and also with the protection of the environment surrounding.

9. PERFORMANCES OF THE CONCRETE MASONRY WITH RECYCLED WOOD CHIPS (II)

IOANA SORINA ENŢUC, DORINA NICOLINA ISOPESCU, LAURENŢIU CRISTINEL BAGDASAR, GABRIEL OPRIŞAN, IULIAN DANIEL ZAPODEANU, SEBASTIAN GEORGE MAXINEASA, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, Volumul 65 (69), Numărul 1, 2019, Secţia CONSTRUCŢII. ARHITECTURĂ

Abstract

The purpose of this study is to obtain an environmentally friendly building material based on recycled wood chips resulted from different industries as wood waste. The wood waste management of any field and its recycling in obtaining other resources further used to develop useful products for masonry structures is a way to mitigate the environmental effects of pollution. The usage and application of these materials or construction products is encouraged by their mechanical and physical performances according to the variation of 50 and 25 wood chips percentage reported to the aggregates’ volume. Compressive strength and density were establishing by experimental test and added to bending strength from a previous study. This research shows the influence of wood chips as a light aggregate and recycled material included in the cement mass on the mechanical properties and density of the material.

Keywords: light aggregate; wood waste; compressive strength; bending strength; lightweight blocks.

10. Analysis of contemporary solar house in terms of sustainability criteria

Dorina Nicolina Isopescu, Aurora Irina Dumitrașcu, Călin Gabriel Corduban, Cosmin Ţâşnei, IOP Conference Series. Materials Science and Engineering; Bristol Vol. 586, Iss. 1, (Aug 2019). DOI:10.1088/1757-899X/586/1/012010

Abstract

When discussing the importance of sustainability principles for both architecture and construction fields, the selection and analysis of design directions (from concept to implementation phase) represent a major topic of the whole integrated process. The constructions sector has already established itself worldwide as an important consumer of both energy and resources. Therefore, the long life of the edifices implies that initial design decisions (conceptual phase) have a significant, amplified effect over time. This paper presents a proposal for a contemporary solar house, with a design in accordance to sustainability criteria. The research highlights the methods applied in the conceptual phase, as well as a comparative study in terms of embodied energy, with two scenarios for the structure: wooden frame versus masonry. Life cycle assessment methods (LCA) have played an important role in optimizing the proposed model in order to deliver a product that is both environmentally and economically efficient.

11. Researches on energy conversion of municipal waste by plasma decomposition for energy-efficiency in civil engineering

M L Lupu, D N Isopescu, I Cucoş, I Antonescu, S G Maxineasa, I-R Baciu, IOP Conf. Ser.: Mater. Sci. Eng. 789 012035, 2020

Abstract

This paper presents the research, technologies and testing equipment developed for the energy plasma conversion of municipal waste in order to enhance energy-efficiency in the civil engineering domain. The purpose of this work is the environmentally friendly improving the efficiency of waste conversion processes by using controlled plasma decomposition reactors developed by the authors, which generate syngas, electrical and thermal energy which can be used in civil engineering.

12. Thermal analysis of a structure made by using cold formed steel sections

Maxineasa, S G; Isopescu, D N; Baciu, I R; Lupu, M L; Dragan, T C. IOP Conference Series. Materials Science and Engineering; Bristol Vol. 789, Iss. 1, (Mar 2020). DOI:10.1088/1757-899X/789/1/012039

Abstract

In the last decades, man-made environmental burdens have led to a significant increase of negative effects felt by the human race. Thus, some industrial sectors have developed and implemented a series of solutions with the goal of minimising their negative ecological impact. Taking into account that the construction sector is one of the most important economic players in every national economy, one that has a tremendous negative impact over the environment, in the last years, various recommendations and limitations have been drawn in order to reduce the consumption of non-renewable energy. In order to constantly reduce the impact of the built environment over the natural one, civil engineers should develop and promote sustainable solutions that have a direct effect on improving the environmental performances of the built environment. One such solution is the use of cold formed steel sections (CFS) for building new structures. This paper analyses the linear thermal transmittance of the thermal bridge formed by the vertical steel studs inside the external walls. The results show that these steel elements can be used in order to build energy efficient buildings.

Keywords: Impact analysis; Studs; Cold-formed steel; Civil engineers; External walls; Urban environments; Thermal analysis; Economics; Thermal bridges; Steel structures; Cold working

13. HYGROTHERMAL BEHAVIOUR OF ENVELOPE ELEMENTS AN OVERVIEW OF ITS DETERMINATION IN-SITU

Pruteanu, Marian; Isopescu, Dorina Nicolina; Enţuc, Ioana-Sorina; Maxineasa, Sebastian; Zărnescu, Constantin. Buletinul Institutului Politehnic din lasi. Sectia Constructii, Arhitectura; Iasi Vol. 66, Iss. 1, (2020): 21-34.

Abstract

In the current context - where climate change has become not only a certitude but also, according to several studies, even irreversible - the mitigation of the negative impact of human niche on the environment has become an absolute value in the underlying systems of value within human society. The accelerating rhythm of climate transformations suggests that the global scientific society has been taken by surprise. In the field of civil constructions, responsible for a significant amount of gas with greenhouse effects - caused by both the energy input for their exploitation and the energy embodied in their execution - substantial efforts have been made lately in order to implement the principles of sustainable development. To this end, complex material and compositions were designed, to obtain higher energetic efficiency levels. Whereas the building materials are assessed before the execution, their behaviour in situ has not been analysed most of the times. Furthermore, the analysis methods are limited and they involve long-term monitoring processes. The paper proposes a synthesis of the analysis methods of the hygrothermal behaviour of the systems of envelope in-situ.

Keywords: energetic efficiency; envelope elements; hygrothermal behaviour; experimental determinations in-situ; numerical modelling.

14. Comparative Analysis of the Effect of Different Types of Green Roofs over the Linear Thermal Bridges

I-R Baciu; Isopescu, D N; Taranu, N; Lupu, M L; Maxineasa, S G. IOP Conference Series. Materials Science and Engineering; Bristol Vol. 916, Iss. 1, (Sep 2020). DOI:10.1088/1757-899X/916/1/012004

Abstract

During recent years, it appears in the background of global discussions the negative impact resulted from the daily humans’ activities. Taking into account the present surface of the built environment and also the fact that this area will significantly increase shortly, it can be considered that using the buildings to develop new solutions like green roofs. The expanding benefits of a green roof emphasize the key role of this structure in the overall thermal performance of buildings and microclimate conditions of indoor spaces. The main objective of the study is to analyse and to interpret the influence of all three main categories of a green roof on the heat flow, in the thermal bridges developed structurally in buildings. The study based on the structural elements of each type of roof, their thermic characteristics and the principal types of thermal bridges will represent a comparison between the thermal impact of a classical terrace roof and that of the extensive, semi-intensive and intensive green roof. In conclusion, the unpredictable results obtained for the analysed thermal parameters let conclude that the green roof solution in all the three forms has an environmental impact, in terms of both sustainability and aesthetics.

Keywords: SubjectRoofing; Heat transmission; Urban environments; Roofs; Structural members; Microclimate; Environmental impact; Green buildings; Thermal bridges; Thermodynamic properties

15. Structural Behaviour of Masonry Walls Made with Ecological Bricks

Enţuc Ioana-Sorina, Mihai Petru, Isopescu Dorina Nicolina, Bagdasar Laurenţiu Cristinel, Buletinul Institutului Politehnic din lasi. Sectia Constructii, Arhitectura, 66 (70) 2, 2020, Pages: 47-54

Abstract

The aim of this research is to obtain an environment friendly construction product as a brick unit based on wooden waste incorporated in concrete used for structural elements in case of low-rise building. This paper presents the structural behaviour of masonry walls made from hollow blocks with recycled wood chips. The influence of the percentage of wood chips variation, as well as of the length of the structural wall, on the load-bearing capacity of the masonry made with blocks that include wooden waste was analysed. The study highlights that the variation, from 4 to 6 m, of the wall length significantly influences the load-bearing capacity of the analysed masonry, while the variation of the percentage of wooden waste as wood chips relative to the volume of aggregates, 25% and 50%, causes small changes in achieving the bending or shear capacity of the masonry made with ecological blocks.

Keywords: ecological block; wooden waste; environment friendly; light aggregate; bearing capacity

16. Green roofs – modern solutions for greening buildings

I R Baciu, N Taranu, D N Isopescu, M L Lupu, T C Dragan, S G Maxineasa, IOP Conf. Ser.: Mater. Sci. Eng. 789 012001, 2020

Abstract

In a society intensively urbanized, nature and green spaces have an extremely important and determined role. Solutions that are integrating different modern techniques related to a new or an existing building, with a tremendously positive effect over the natural building and horticultural sectors will represent an important factor in reducing the negative effect over the environment on a global scale. These smart solutions could extend the garden effect from the ground to the elevated levels of the building. Even if at the present moment there are different classic solutions to realize a green roof, in the last decades, have been developed different new and modern techniques for the greening environment. Taking into account all the above mentioned, the aim of the paper is to present the modern green roof systems considering all the changes that have occurred over time, and also to analyze a series of examples of how this concept has been adopted in different parts of the world and for varies structural systems. The authors consider that the study is very important in order to completely understand the characteristics of these systems and their main components, in order to properly design and implement them according to the present environmental needs. It is believed that the knowledge of this concept and its evolution and tendencies will help solve a series of ecological and social problems.

17. Determination of Physicomechanical Characteristics of the Cement Mortar with Added Fiberglass Waste Treated with Hydrogen Plasma

Lupu ML, Isopescu DN, Tuns I, Baciu I-R, Maxineasa SG, Materials. 2021; 14(7):1718

Abstract

Solving the environmental problems and the economic aspects of the construction sector represent a global priority. The considerable quantities of raw materials and the energy consumed by this sector make it one of the most polluting economic activities. Fiberglass in various forms is widely used in the construction sector. In the manufacturing process and during the usage of fiberglass products, a significant amount of indestructible waste results, negatively impacting the environment. An innovative solution for utilizing this type of waste is the treatment with hydrogen plasma. This process results in two products: the first in the gaseous state used to obtain synthetic fuel and the second in solid-state, named slag. The composition of solid waste contains chemical compounds that can increase their strength if used as additives in mortars or concretes. This study presents the laboratory tests on mortars, in which a part of the cement amount was replaced with the solid component resulting from the plasma treatment of glass fiber waste. The results showed that replacing a part of the cement with these materials is a solution that minimizes the ecological footprint of the buildings.

Keywords: fiberglass; hydrogen; plasma; cement; mortar; vitrification

18. Advanced system control for hydrogen plasma conversion of industrial hazardous recyclable liquid waste

Iulian Cucos, Ion Antonescu, Dorina Isopescu, Daniel Lepadatu, Maria-Oana Agavriloaie, Vasile Caunii, Vlad-Catalin Cucos, Environmental Engineering and Management Journal, April 2021, Vol. 20, No. 4, 593-603

Abstract

This paper presents the design of some equipment within an installation for plasma processing of liquid hazardous waste with hydrogen. The authors present the design and simulation in Solidworks and Ansys of hydrogen plasma torches components used for heat treatment of hazardous industrial liquids, the development in Matlab & Simulink of algorithms for controlling the power sources of torches and the non-interactive multivariable control system through thermoregulatory with PID and PID one step ahead control laws from the power supply of the reactor, and the dimensional design and functional simulation of the pump blade that ensures the circulation of the cooling liquid (water) in the torch.

Keywords: hydrogen, liquid waste, management, plasma, PID and one-step predictive, recycling, systems design, zero emissions

19. Hydrogen plasma conversion system of municipal recyclable waste in energy

Iulian Cucos, Ion Antonescu, Dorina Isopescu, Daniel Lepadatu, Maria-Oana Agavriloaie, Vasile Caunii, Vlad-Catalin Cucos, Environmental Engineering and Management Journal, April 2021, Vol. 20, No. 4, 625-634

Abstract

The paper presents a synthesis of the main technologies used in municipal waste management, highlighting the main technical characteristics, advantages and disadvantages, the main objective is to improve the technical and economic performance of a plant that uses an innovative and environmentally friendly technology based on hydrogen plasmas for the processing of municipal recyclable waste as a source of renewable and cheap energy. Plasma gasification is a innovative process, efficient technically and economically, with low impact on the environment and facilities using this technology have reduced carbon footprint. The main equipment of the installation is the assembly consisting of the reactor equipped with plasma torch and the hydrogen plasma gas purification system, powered by power sources controlled by automation devices controlled by advanced control algorithms that act online and anticipate thermal processes and chemicals that occur in the reactor.

Keywords: hydrogen, liquid waste, management, plasma, PID and one-step predictive, recycling, systems design, zero emissions

20. Helix spin economy and plasma waste recovery in construction and building materials industry

Ionel-Ciprian Alecu, Daniel Lepadatu, Dorina Isopescu, Iulian Cucos, Maria-Oana Agavriloaie, Ion Antonescu, Environmental Engineering and Management Journal, April 2021, Vol. 20, No. 4, 567-576

Abstract

The circular economy is a development model that redefines economic growth by decoupling it from the consumption of resources (especially non-renewable) and conveys waste back into productive activities, as raw materials for other production circuits, thus helping the increase of resource efficiency, and reducing the impact of economic activity in the environment. As one of the main aspects addressed by the circular economy concept, waste recycling can limit sometimes the practical and conceptual nature of this system. Starting from the concept of circular economy we propose a new concept called helix spin economy, in which the plasma processing technologies applied to industrial and municipal waste have a special importance. Plasma gasification of municipal waste leads to the production of valuable and safe outcomes for the environment, such as syngas, metals and glassy rocks. As for assessing the modeling of the complex economic processes that govern the helix spin economy, the research team considers fuzzy mathematics and the theory of uncertainty.

Keywords: fuzzy mathematics, helix spin economy, hydrogen plasma gasification, municipal waste

21. PARTICULARITIES OF SYNTHETIC WOOD - A BIOMATERIAL WITH RECYCLED WASTE

Daniel Lepadatu, Dorina Isopescu, Loredana Judele, Iulian Cucos, Ion Antonescu, Ionel-Ciprian Alecu, Environmental Engineering and Management Journal, April 2021, Vol. 20, No. 4, 585-592

Abstract

Depletion of world resources, increasing pollution and climate change effects, make it necessary a shift from linear economy to systemic economy – an economy of technologies integrated to reach a non-polluting, zero emissions production system. Transition to renewable resources requires replacing the existing crude oil refinery with biomass refinery. Along with conventional biomass refinery technologies, bioengineering and nano-technologies are becoming significant players of systems in the design of clusters of integrated biorefinery technologies. This study presents a set of samples obtained by combining biomass waste such as wood waste with other types of recyclable construction waste compatible with the new material. In the context of the growing economy of raw materials, it is considered necessary to develop a material capable of absorbing as much waste as possible from nearby areas. Thus, the investigated samples are presented and analyzed to highlight their physicochemical properties and compatibility with integrated waste and, last but not least, to significantly improve these characteristics by introducing nanoparticles obtained by plasma conversion of municipal waste.

Keywords: artificial biomaterial, recyclable waste, synthetic wood

22. Researches on energy-efficient plasma conversion of fibreglass waste into new ecological materials for building industry

I Antonescu, D N Isopescu, I Cucoş, V Caunii, I C Alecu, M L Lupu, IOP Conf. Ser.: Mater. Sci. Eng. 1138 012001, 2021

Abstract

The paper presents the researches, prototype laboratory equipment and technologies developed by the authors for the plasma conversion of fiberglass waste into useful materials for building industry. The aim was to increase the energy efficiency of conversion processes and to obtain technologies and materials with better proprieties for civil engineering appliances and reduced impact on the environment.

23. Conversion of industrial liquid construction waste with plasma on hydrogen

Iulian Cucos, Dorina-Nicolina Isopescu, Ion Antonescu, Ciprian-Ionel Alecu, Vasile Caunii, Vlad-Catalin Cucos, Maria-Oana Agavriloaie, International Scientific Conference CIBv - Civil Engineering and Building Services, 5th-6th November 2021, IOP Conf. Series: Materials Science and Engineering 1138 012018

Abstract

This paper presents a modern system for conversion with plasma with hydrogen of industrial liquid waste which has implemented a control system through thermoregulatory with PID control laws. Modeling and simulation of thermochemical plasma process performed using specialized software Matlab & Simulink, Ansys allows the optimum control of the temperatures and chemical reactions of the plasma reactor on hydrogen, allowing the conversion of hazardous industrial liquid waste into electrical and thermal energy and useful raw materials that can be reused in the production process.

24. Advanced technology of municipal solid waste conversion for a circular economy

M L Lupu, D N Isopescu, S G Maxineasa, I-R Baciu, I Antonescu, I Cucos, IOP Conf. Ser.: Mater. Sci. Eng. 1138 012028, 2021

Abstract

One of the most important environmental problems of the big urban areas is represented by the large volume of waste resulted from different human activities. In the last decades, different technologies have been developed to resolve this significant issue, and the most representative is the conversion of municipal solid waste (MSW) in different types of by-products. The first part of this paper presents the current state of plasma conversion technology that can be used for processing waste, and also, its potential in the construction sector which could be taken advantage of the by-products (syngas and slag) resulted from the plasma gasification of municipal solid waste (MSW), to enhance energy-efficiency in this domain. In the second part of the paper, there are analyzed different technologies for managing and processing municipal solid waste (MSW), which can be used nowadays, and the parameters, related to the costs, the period of use, the energy consumption and the environmental impact. All these aspects are compared with those of plasma conversion technology. The plasma conversion system can be commercialized successfully, and its costs can be reduced by generating income in the form of by-products and added-value in producing performant products in a circular economy.

25. Influence of Green Terraces in Evaluating the Action of Wind on Buildings

Isopescu Dorina Nicolina, Maxineasa Sebastian George, Baciu Ioana Roxana, Global Journal of Engineering Sciences, ISSN: 2641-2039, Volume 8, Issue 3, 2021, DOI: 10.33552/GJES.2021.08.000688

Abstract

The development of the construction sector, as a result of the special emphasis of recent years in the implementation of the principles of sustainability, has included various directions: from structural certification of environmentally friendly materials in terms of their durability and carbon dioxide emissions, and the innovation of building systems respecting the energy efficiency principles requirements, until to the innovation of the shape and volume concepts of buildings. All over the world there are recognized examples of nature-friendly architecture. The complexity of sustainable development in construction is increasingly becoming cross-cutting research, which covers the integrated techniques of materials science, building physics, with the circular economy, and with plant science. This challenge offers new opportunities for buildings to become less polluting and more resistant to climate change. Green buildings, in fact, green roofs and facades, help to create viable and sustainable built spaces. The benefits are much more than the structural or environmental protection, green structural components in buildings can contribute to the well-being of occupants, such as noise reduction, and can improve indoor air quality. This article examines the importance of green roofs in sustainable buildings and their effect on the strength and stability of buildings against wind action, based on design regulation in force. In addition to the general presentation of the literature, several recent applications of greenery in projects are presented, to illustrate the architectural added value.

Keywords: Green terrace; Wind actions; Sustainability; Building stability; Building durability

26. Study of condensation risk in ecological blocks with recycled wood aggregate

Marian Pruteanu, Ioana Sorina Ențuc, Dorina Nicolina Isopescu, Gabriel Oprișan, Laurențiu Cristinel Bagdasar, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, 2021

Abstract

Concrete is a building material with a continuous demand in the construction industry due to the convenient price-performance ratio. On the other hand, concrete is not an environmentally friendly material. Thus, in order to obtain a sustainable material, wood waste can be recycled and used as light aggregates in the manufacture of precast ecological building blocks. These elements must satisfy not only structural criteria but also functional requirements. In addition, thermal contribution is important in reducing energy consumption over the life of the building. The presence of moisture on the exterior walls due to the appearance of condensation will decrease the thermal performance of building materials. This paper analyses the appearance of condensation in the outer wall made of ecological blocks by the Glaser method. In this study, various solutions were presented to reduce the risk of condensation in ecological concrete blocks with recycled wood as light aggregates.

27. The permeability analysis in case of tuff and limestone addition in the concrete composition

D T Babor, M Butnariu, D Isopescu, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, 2021

Abstract

This research aimed to analyse the effects of using tuff and limestone as supplementary pozzolanic materials on the permeability of a classic C12/15 concrete composition. There were designed two types of concrete compositions with different degrees of permeability, namely P8 10 and P12 10 as reference concrete compositions and eight experimental concrete compositions with tuff in 6% and 10% of the cement quantity and with limestone in the same proportions. According to results, the tuff and limestone led to the decrease of concrete permeability, the best values being registered in the case of using 10% tuff in the concrete composition with P8 10 class of permeability.

28. Low - permeability ecological concrete mix, by means of employing several active admixtures

Dănuț-Traian Babor, Dorina-Nicolina Isopescu, Tudor-Cristian Petrescu, Daniel Covatariu, BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI, Publicat de Universitatea Tehnică „Gheorghe Asachi” din Iaşi, 2021

Abstract

There exists an interest to realize impermeable concrete, which would have many applications in water transport or storage structures, such as tanks, reservoirs, gutters and pipes. Furthermore, it would be possible to use such a type of concrete in other structures where the water pressure represents an exterior action, such as basement walls, caissons and slab foundations. However, absolutely impermeable concrete is almost impossible to be obtained, hence low – permeability concrete is the correct technical term. In the current article, several samples of such concrete, containing active admixtures, are shown and relevant conclusions are drawn.

29. Advanced tools for optimization and efficiently monitoring behaviour in service stage of buildings using renewable energy

D.I. Morariu, I. Serbanoiu, M. Miron, D. Lepadatu, IOP Conference Series. Materials Science and Engineering, Vol. 485 (2019)

Abstract

In the topographical surveying works devices have got among the required accessories also tools called tripod. They have the role of correctly installing and settling the equipment above the station point in order to perform the measurements. Various types of tripods are known: the classic tripod (made from aluminum or wood), the adjustable laser tripod, the elevator tripod, the tripod for supporting and adjusting the picket. The aim of this scientific paper is to present my invention that is concerned on a new type of tripod device with photovoltaic cells called mobile solar tripod which has the purpose of providing the energy needed for the equipment used and thus extending the duration of survey measurements by using renewable energies. The tripod being an almost universal accessory along with other topographic instruments, it can be used for some topo-geodetic activities such as monitoring behavior in service stage of buildings, marking the points on the ground, determining ground elevations and other works that require a long time for the objects studied. This present work will describe the advantages and disadvantages of using the existing tripods compared to the new proposed device.

30. Advanced systems for heat treatment controlling of electrical furnaces

I. Antonescu, C. I. Alecu, D. Lepadatu, IOP Conference Series. Materials Science and Engineering, Vol. 485 (2019)

Abstract

This paper presents a modern electric heat treatment which has implemented an electric furnace control system through thermoregulatory with PID control laws. An important aspect is the development of a mathematical model for controlling electrical heating systems for heat treatments based on mathematical modelling to predict the mechanical properties and structure of the play resulting from heat treatment. Validation of the experimental research of heat treatment designed by the mathematical model for predicting mechanical properties and structure of the finished part and model for controlling electrical heating system based on PID adjustment algorithms consists in structural analysis to determine the chemical composition, structural analysis by light microscopy, electron microscopy SEM and EDX quantitative analysis, determination of hardness alloys and physical and mechanical of the turbine blades component of a plasma torch on hydrogen made of heat-treated steel.

31. Neural network architecture optimization by analyse the mechanical characteristics of civil engineering materials

C. I. Alecu, L. Judele, M. Movila, D. Lepadatu, IOP Conference Series. Materials Science and Engineering, Vol. 485 (2019)

Abstract

Our proposal for this paper is to diversify the architecture of neural networks in order to optimize it and to obtain the best performing configurations that minimize errors of predictive mechanical properties of polymeric concrete. In this paper different architectures of artificial neural networks will be used for investigating the flexural strength of polymer concrete with fly ash and fibres. In the present study the epoxy resin was used for binding the aggregates. In the composition were introduced near the fly ash, used as filler, the cellulose fibres for improving the properties. The characteristics of these artificial neural networks architectures will be presented and analysed in order to choose the one that minimizes the prediction errors of the mechanical characteristics of polymer concrete and presents an optimal configuration that allows a high working speed that can adapt to this type of approaching the problem with a strong nonlinear character. By using this modern predictive methods, it was attempted to highlight its basic character - learning by examples specific to the human brain but much more efficient due to the mathematical models of the activation functions and the interconnection between the layers of neurons that exponentially increase their ability to adapt to strong nonlinear phenomena. Thus one can say that such a prediction helps to reduce the number of real experiences and can greatly contribute to obtaining the optimal configuration of parameters necessary to obtain a desired mechanical characteristic of the analysed concrete.

32. Photovoltaic panels cost optimization with flexible polymer semiconductor cells using fuzzy logic

M. Miron, D. I. Morariu, I. Cucos, C. I. Alecu, L. Judele, D. Lepadatu, IOP Conference Series. Materials Science and Engineering, Vol. 485 (2019)

Abstract

This paper presents the research undertaken by the authors to determine the parameters of electric power produced by a photovoltaic panel using flexible semiconductor polymer cells, aiming a comparative study between this panel and other types of conventional photovoltaic panels, with monocrystalline, polycrystalline and amorphous silicon, based on technical and economic indicators, established under uncertainty conditions. We will also present the variation of these dimensions according to the incidence angle of solar radiation. Thus, researches will show that for its value between 36-38 degrees, you get very good conversion yields. The economic study presented also reveals that under uncertainty there is a correspondence between the panel type and its physical and economic characteristics.

33. Optimisation of several estimating functions by multicriterial analysis of civil engineering structure in service stage monitoring

Lepadatu Daniel, Isopescu Dorina, Rusu Ion, Judele Loredana, Săndulache Gabriel, ACROSS Numărul 6(2) / 2022 / ISSN - /ISSNe 2602-1463

Abstract

In order to ensure the safety of engineering structures and especially those with special regimen such as the viaducts requiring careful monitoring of spatial displacements, it is necessary to find an optimal combination of criteria that are evaluated by a multi-criteria analysis to avoid major structural degradation and their effects on of the entire structure that can generate catastrophes with major losses of human lives. In this paper we will present an optimization of the estimation functions of the evaluation criteria behaviour for the time monitoring of an engineering structure. In this paper, we are analysing a structure that has 50 years and that has a vital significance for Galati city from Romania. It is a 1.3 km-long viaduct structure connecting the city of Galati with ArcelorMittal steel company. The current legislation requires a plan for permanent monitoring of displacement in order to avoid accidents that can lead to loss of human life. Thus, we will quantify and discuss the effects of the different evaluation criteria behaviour and we will choose those that maximize the user's chances of responding without departing from those values that keep their study credible. In order to obtain the results of the multicriteria analysis, three monitoring cycles with three types of instruments on more than 30 tracking points were designed and performed.

34. Corrosion - an undesirable phenomenon for reinforcement of advanced mortars and concrete

Judele Loredana, Isopescu Dorina, Rusu Ion, Lepadatu Daniel, ACROSS, Numărul 6(2) / 2022 / ISSN - /ISSNe 2602-1463

Abstract

Constructions made out of mortar and cement concrete are unveiled to advanced chemical corrosion processes, especially when placed in aggressive environments. The study follows the behaviour of concrete with a slag content of 10 % exposed to chlorine corrosion, as well as carrying out analyses aimed at monitoring the evolution of mechanical resistance of concrete samples, containing slag when immersed in various aggressive solutions. The corrosive agents acting on the above-mentioned elements are in particular chlorine ions. These compounds may also be found in considerable quantities in industrial emissions and their effect is intensified by an increase in humidity, temperature or steam, or other corrosive gases, possibly accompanied by inadequate ventilation. The analysis of complex chemical processes highlights the influence of different corrosive agents on the resistance of this concrete.

35. The use of perlite in civil engineering applications

S.G. Maxineasa, D.N. Isopescu, M.L. Lupu, I.-R. Baciu, L. Pruna, C. Somacescu, IOP Conference Series Materials Science and Engineering 1242, 2022

Abstract

In the last years, research applications in the construction sector have taken a different turn due to rapid urbanization and the necessity to protect the environment and create a balance between the natural and built environments. Taking into account the fact that the thermal efficiency of buildings has an important influence over the environmental performances of the construction sector, the civil engineering specialists have tried to develop and use different new solutions in order to improve this essential building characteristic. Thus, different new materials have been used with the goal of reducing the overall thermal transmittance of the envelope elements and of the total energy consumption needed for heating and cooling. Perlite is one of the materials that have been considered for developing new energy efficient construction applications. The main goal of the present paper is to present all the relevant solutions that have been developed and used in the construction sector that consider perlite as a component part. The present study is the first part of a more extensive research program that takes under evaluation the possibility of using perlite as a thermal insulating material for different constructions.

36. Ventilated façade solutions

I.-R. Baciu, D.N. Isopescu, M.L. Lupu, S.G. Maxineasa, L. Pruna, S. Dan, IOP Conference Series Materials Science and Engineering 1242, 2022

Abstract

Reducing the energy consumption needed for creating suitable indoor conditions has become a significant issue on a global scale. The building's envelope and service systems have the most important influence over the amount of energy consumed. This aspect is related to reducing the heat flux across the building envelope in summer conditions and preventing the condensation and infiltration risk in the winter period. The research regarding ventilated façades has advanced taking into account these advantages, which emphasized the need to study and create constructive solutions adapted to the conditions. In this context, this paper represents a brief introduction to ventilated façades solutions, taking into account the definition, their characteristics, the principal constructive elements, the main types of ventilated facades, and last, but not least, their advantages and disadvantages. The authors believe that the study is critical in fully comprehending the characteristics of these systems and their primary components, as well as designing and implementing them in accordance with current environmental needs. It is anticipated that comprehending this concept, as well as its evolution and trends, can contribute in the resolving of a number of ecological and societal issues.

37. The influence of green terrace roofs on wind dynamic parameters: wind tunnel testing

Ioana-Roxana Baciu, Dorina Nicolina Isopescu, Nicolae Țăranu, Sebastian George Maxineasa, Proceedings 8th European-African Conference on Wind Engineering

Abstract

Green terrace roofs have been developed to minimize the negative environmental impacts of the building sector. To promote their acceptance, these solutions should be described imply utilizing coefficient values and analytical equations usually associated with standardized building design techniques. Wind effects on structures should be considered when evaluating variable loads operating on buildings. The wind tunnel testing has advanced at an impressive rate, to the point where laboratory investigation of natural phenomena results in the determination of design parameter values. The primary objective of this research work is to determine the effect of green terrace roofing on the values of building design parameters when subjected to wind action.

Key words: green terrace roofs, building sector, wind effects, wind tunnel.

38. Hempcrete - modern solutions for green buildings

M.L. Lupu, D.N. Isopescu, I.-R. Baciu, S.G. Maxineasa, L. Pruna, R. Gheorghiu, IOP Conference Series Materials Science and Engineering 1242, 2022

Abstract

It is widely established that the building industry has a negative impact on the environment and a significant influence on the phenomena that contribute to climate change. Traditional construction materials, such as cement, contribute considerably to environmental pollution. Given the enormous quantity of energy and materials used by the construction sector, this industry must adopt more sustainable practices. Nowadays, an increasing number of natural building materials are used in the structural component or the insulation of buildings. As a result, natural construction materials may be a superior alternative to accomplish this goal. This article discusses the features and applications of hempcrete in the building industry. Hempcrete is a sustainable material composed of industrial hemp, lime as a binder, and water. Due to hemp's porous structure, it has deformation capacity, sound-absorbing qualities, better hygrothermal properties than conventional concrete, and, depending on the proportions of hemp, lime, and water, fire resistant capabilities due to the presence of lime.