Innovative Composites with Carbon Nanofillers for Self-Sensing Structural RC Beams

2018 ◽  
Vol 19 ◽  
pp. 12-22 ◽  
Author(s):  
A. D'Alessandro ◽  
A. Meoni ◽  
F. Ubertini
Keyword(s):  
Research Work ◽  
Construction Materials ◽  
Reinforced Concrete Beam ◽  
The Self ◽  
Electrical Performance ◽  
Structural Safety ◽  
Cement Pastes ◽  
The Matrix ◽  
Behavior Modifications ◽  
Carbon Nanofillers

The progress of nanotechnology resulted in the development of new instruments in the civil engineering and its applications. In particular, the use of carbon nanofillers into the matrix of construction materials can provide enhanced properties to the material in both of mechanical and electrical performance. In constructions, concrete is among the most used material. Due to the peculiarities of its components and its structure, it is suitable to modifications, at the nanometer level too. Moreover, to guarantee structural safety it is desirable to achieve a diffuse monitoring of structures in order to identify incipient situations of damages and possible risk for people. The ideal solution would be to realize structures able to identify easily and quickly their behavior modifications. This paper presents a research work about the characterization of the self-sensing abilities of novel cementitious composites with conductive carbon nanoinclusions and their application into a structural reinforced concrete beam. The self-sensing evidence is achieved through the correlation between the variation of strains and the variation of electrical resistance or resistivity. Nanomodified cement pastes with different carbon nanofillers has been tested. The experimental campaign shows the potentialities of this new types of sensors made of nanomodified concrete for diffuse Structural Health Monitoring.

Piezoelectric β-polymorph formation of new textiles by surface modification with coating process based on interfacial interaction on the conformational variation of poly (vinylidene fluoride) (PVDF) chains

2020 ◽  
Vol 91 (3) ◽  
pp. 31301
Author(s):  
Nabil Chakhchaoui ◽  
Rida Farhan ◽  
Meriem Boutaldat ◽  
Marwane Rouway ◽  
Adil Eddiai ◽  
...  
Keyword(s):  
High Efficiency ◽  
Vinylidene Fluoride ◽  
Research Work ◽  
Research Area ◽  
Interfacial Interaction ◽  
Tetraethyl Orthosilicate ◽  
Poly Vinylidene Fluoride ◽  
Carbon Nanofillers ◽  
The Impact ◽  
Advanced Applications

Novel textiles have received a lot of attention from researchers in the last decade due to some of their unique features. The introduction of intelligent materials into textile structures offers an opportunity to develop multifunctional textiles, such as sensing, reacting, conducting electricity and performing energy conversion operations. In this research work nanocomposite-based highly piezoelectric and electroactive β-phase new textile has been developed using the pad-dry-cure method. The deposition of poly (vinylidene fluoride) (PVDF) − carbon nanofillers (CNF) − tetraethyl orthosilicate (TEOS), Si(OCH2CH3)4 was acquired on a treated textile substrate using coating technique followed by evaporation to transform the passive (non-functional) textile into a dynamic textile with an enhanced piezoelectric β-phase. The aim of the study is the investigation of the impact the coating of textile via piezoelectric nanocomposites based PVDF-CNF (by optimizing piezoelectric crystalline phase). The chemical composition of CT/PVDF-CNC-TEOS textile was detected by qualitative elemental analysis (SEM/EDX). The added of 0.5% of CNF during the process provides material textiles with a piezoelectric β-phase of up to 50% has been measured by FTIR experiments. These results indicated that CNF has high efficiency in transforming the phase α introduced in the unloaded PVDF, to the β-phase in the case of nanocomposites. Consequently, this fabricated new textile exhibits glorious piezoelectric β-phase even with relatively low coating content of PVDF-CNF-TEOS. The study demonstrates that the pad-dry-cure method can potentially be used for the development of piezoelectric nanocomposite-coated wearable new textiles for sensors and energy harvesting applications. We believe that our study may inspire the research area for future advanced applications.

scholarly journals The Influence of Mixing Methods of Epoxy Composition Ingredients on Selected Mechanical Properties of Modified Epoxy Construction Materials

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 411
Author(s):  
Izabela Miturska ◽  
Anna Rudawska ◽  
Miroslav Müller ◽  
Monika Hromasová
Keyword(s):  
Tensile Strength ◽  
Epoxy Resin ◽  
Construction Materials ◽  
Preliminary Heating ◽  
Epoxy Composition ◽  
Mixing Speed ◽  
Adhesive Composition ◽  
Adhesive Compositions ◽  
The Matrix ◽  
Level Of Significance

The proper process of preparing an adhesive composition has a significant impact on the degree of dispersion of the composition ingredients in the matrix, as well as on the degree of aeration of the resulting composition, which in turn directly affects the strength and functional properties of the obtained adhesive compositions. The paper presents the results of tensile strength tests and SEM microphotographs of the adhesive composition of Epidian 57 epoxy resin with Z-1 curing agent, which was modified using three fillers NanoBent ZR2 montmorillonite, CaCO3 calcium carbonate and CWZ-22 active carbon. For comparison purposes, samples made of unmodified composition were also tested. The compositions were prepared with the use of six mixing methods, with variable parameters such as type of mixer arm, deaeration and epoxy resin temperature. Then, three mixing speeds were applied: 460, 1170 and 2500 rpm. The analyses of the obtained results showed that the most effective tensile results were obtained in the case of mixing with the use of a dispersing disc mixer with preliminary heating of the epoxy resin to 50 °C and deaeration of the composition during mixing. The highest tensile strength of adhesive compositions was obtained at the highest mixing speed; however, the best repeatability of the results was observed at 1170 rpm mixing speed. Based on a comparison test of average values, it was observed that, in case of modified compositions, the values of average tensile strength obtained at mixing speeds at 1170 and 2500 rpm do not differ significantly with the assumed level of significance α = 0.05.

scholarly journals Characterization of Soldering Alloy Type Bi-Ag-Ti and the Study of Ultrasonic Soldering of Silicon and Copper

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 624
Author(s):  
Roman Kolenak ◽  
Igor Kostolny ◽  
Jaromir Drapala ◽  
Paulina Babincova ◽  
Peter Gogola
Keyword(s):  
Eutectic Reaction ◽  
Research Work ◽  
Copper Substrate ◽  
Liquid Bismuth ◽  
Alloy Type ◽  
Average Shear Strength ◽  
Average Shear ◽  
The Matrix ◽  
Solder Microstructure ◽  
Ultrasonic Soldering

The aim of the research work was to characterize the soldering alloy type Bi-Ag-Ti and to study the direct soldering of silicon and copper. Bi11Ag1.5Ti solder has a broad melting interval. Its scope depends mainly on the content of silver and titanium. The solder begins to melt at the temperature of 262.5 ∘C and full melting is completed at 405 ∘C. The solder microstructure consists of a bismuth matrix with local eutectics. The silver crystals and titanium phases as BiTi2 and Bi9Ti8 are segregated in the matrix. The average tensile strength of the solder varies around 42 MPa. The bond with silicon is formed due to interaction of active titanium with the silicon surface at the formation of a reaction layer, composed of a new product, TiSi2. In the boundary of the Cu/solder an interaction between the liquid bismuth solder and the copper substrate occurs, supported by the eutectic reaction. The mutual solubility between the liquid bismuth solder is very limited, on both the Bi and the Cu side. The average shear strength in the case of a combined joint of Si/Cu fabricated with Bi11Ag1.5Ti solder is 43 MPa.

Characteristics of the Al-Brasses Affected Corrosion Properties

2016 ◽  
Vol 844 ◽  
pp. 38-45 ◽  
Author(s):  
Tatiana Liptáková ◽  
Martin Lovíšek ◽  
Branislav Hadzima
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Research Work ◽  
Construction Materials ◽  
Experimental Methods ◽  
Energy Industry ◽  
Corrosion Properties ◽  
Corrosion Resistant ◽  
Operation Conditions ◽  
Similar Chemical

The Al-brasses are considered corrosion resistant construction materials often used to pipe systems in energy industry, where they are exposed to flowing liquids environments. In that system the brasses are loaded chemically and mechanically. The aim of our research work is to compare corrosion properties of four Al-brasses produced by different manufactures because in operation conditions they have dissimilar reliability and durability. The examined Al-brasses have similar chemical composition but differ in microstructure, surface state what affects their corrosion and mechanical properties. The effect of the mentioned parameters on corrosion and mechanical susceptibility to degradation are investigated by chosen experimental methods.

scholarly journals Bringing optical metrology to testing and inspection activities in civil engineering

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 108
Author(s):  
Luis Martins ◽  
Álvaro Ribeiro ◽  
Maria Do Céu Almeida ◽  
João Alves e Sousa
Keyword(s):  
Large Scale ◽  
Civil Engineering ◽  
National Laboratory ◽  
Research Work ◽  
Construction Materials ◽  
Laser Interferometry ◽  
Suspension Bridge ◽  
Shaking Table ◽  
Optical Metrology ◽  
Future Research

<p class="Abstract">Optical metrology has an increasing impact on observation and experimental activities in Civil Engineering, contributing to the Research and development of innovative, non-invasive techniques applied in testing and inspection of infrastructures and construction materials to ensure safety and quality of life. Advances in specific applications are presented in the paper, highlighting the application cases carried out by LNEC (the Portuguese National Laboratory for Civil Engineering). </p><p class="Abstract">The examples include: (i) structural monitoring of a long-span suspension bridge; (ii) use of close circuit television (CCTV) cameras in drain and sewer inspection; (iii) calibration of a large-scale seismic shaking table with laser interferometry; (iv) destructive mechanical testing of masonry specimens.</p><p class="Abstract">Current and future research work in this field is emphasized in the final section. Examples given are related to the use of Moiré techniques for digital modelling of reduced-scale hydraulic surfaces and to the use of laser interferometry for calibration of strain measurement standard for the geometrical evaluation of concrete testing machines.</p>

scholarly journals Functional Application for the Corn Leaf Fibre to Make Reinforced Polymer Composites Sheet

2021 ◽  
Author(s):  
Ramratan Guru ◽  
Anupam Kumar ◽  
Rohit Kumar
Keyword(s):  
Volume Fraction ◽  
Agricultural Waste ◽  
Matrix Material ◽  
Research Work ◽  
Weight Fraction ◽  
Natural Fibre ◽  
Raw Material ◽  
Corn Husk ◽  
The Matrix ◽  
Composite Product

This research work has mainly utilized agricultural waste material to make a good-quality composite sheet product of the profitable, pollution free, economical better for farmer and industries. In this study, from corn leaf fibre to reinforced epoxy composite product has been utilized with minimum 35 to maximum range 55% but according to earlier studies, pulp composite material was used in minimum 10 to maximum 27%. Natural fibre-based composites are under intensive study due to their light weight, eco-friendly nature and unique properties. Due to the continuous supply, easy of handling, safety and biodegradability, natural fibre is considered as better alternative in replacing many structural and non-structural components. Corn leaf fibre pulp can be new source of raw material to the industries and can be potential replacement for the expensive and non-renewable synthetic fibre. Corn leaf fibre as the filler material and epoxy as the matrix material were used by changing reinforcement weight fraction. Composites were prepared using hand lay-up techniques by maintaining constant fibre and matrix volume fraction. The sample of the composites thus fabricated was subjected to tensile, impact test for finding the effect of corn husk in different concentrations.

La fruizione dei beni culturali come contributo del turismo allo sviluppo delle cittŕ d'arte

2009 ◽  
pp. 59-72
Author(s):  
Marco Martinelli
Keyword(s):  
Cultural Heritage ◽  
Key Words ◽  
Research Work ◽  
Cultural Development ◽  
The Self ◽  
Modern City

- The author examines the ways in which cultural heritage is used in the art cities. The evidence from research work on the characteristics of visitors of four museums of Rome are shown. Two types emerge: the mass tourist "with a collective look" and the self-directed "romantic" tourist. Tourism in art cities enhances the cultural development of cities.Key words: tourism, art city, post modern, city.

scholarly journals Physical Properties of Concrete Containing Graphene Oxide Nanosheets

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1707 ◽  
Author(s):  
Yu-You Wu ◽  
Longxin Que ◽  
Zhaoyang Cui ◽  
Paul Lambert
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Graphene Oxide ◽  
Flexural Strength ◽  
Portland Cement ◽  
Physical Properties ◽  
Ordinary Portland Cement ◽  
Construction Materials ◽  
Split Tensile Strength ◽  
Cement Pastes

Concrete made from ordinary Portland cement is one of the most widely used construction materials due to its excellent compressive strength. However, concrete lacks ductility resulting in low tensile strength and flexural strength, and poor resistance to crack formation. Studies have demonstrated that the addition of graphene oxide (GO) nanosheet can effectively enhance the compressive and flexural properties of ordinary Portland cement paste, confirming GO nanosheet as an excellent candidate for using as nano-reinforcement in cement-based composites. To date, the majority of studies have focused on cement pastes and mortars. Only limited investigations into concretes incorporating GO nanosheets have been reported. This paper presents an experimental investigation on the slump and physical properties of concrete reinforced with GO nanosheets at additions from 0.00% to 0.08% by weight of cement and a water–cement ratio of 0.5. The study demonstrates that the addition of GO nanosheets improves the compressive strength, flexural strength, and split tensile strength of concrete, whereas the slump of concrete decreases with increasing GO nanosheet content. The results also demonstrate that 0.03% by weight of cement is the optimum value of GO nanosheet dosage for improving the split tensile strength of concrete.

scholarly journals A microsatellite library for Carica papaya L. cv. Sunrise solo

2003 ◽  
Vol 25 (2) ◽  
pp. 263-267 ◽  
Author(s):  
Silvia Correa Santos ◽  
Carlos Ruggiero ◽  
Cristina Lacerda Soares Petrarolha Silva ◽  
Eliana Gertrudes Macedo Lemos
Keyword(s):  
Molecular Markers ◽  
Related Species ◽  
Carica Papaya ◽  
The Self ◽  
Pollination Efficiency ◽  
Breeding Programs ◽  
The Matrix ◽  
Papaya Tree ◽  
Unique Band ◽  
Sexual Form

In experimental areas of the Education and Researches Ilha Solteira and Jaboticabal UNESP/Campus farms were selected and tagged 20 hermaphrodite plants and 20 feminine of cultivar Sunrise Solo, Improved Sunrise Solo cv.72/12 and Baixinho of Santa Amália.The seeds origined of the selected fruits were cropped to be analysed the self-pollination efficiency and frequency of the sex in the progenies. After that, samples of the young leaf of the matrix plants were colected for the extration of the DNA. It was built five library enriched of microsatellite sequencies, using probes (TCA)10, (TC)13, (GATA)4, (CAC)10 e (TGAG)8.It was possible the development of the primers only in the library that has utilized the probe (TCA)10. This probe allowed the design of 32 primer pairs. From these, 31 presented pattern of unique band in agarose Metaphor and in acrilamide. For primer S36 were observed 2 bands, but with no polymorphism to differentiation in the sexual form at papaya tree culture. However, these primers can be tested, in the futures, in the investigation of the others features in segregated populations of this specie and the related species, germoplasm analysis, cultivars identification, parent evolution and molecular markers for the assisted plant breeding programs.

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