scholarly journals Carbon Nanotubes-Filled Siloxane Composite Foams for Oil Recovery Application: Compression Properties

Fibers ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 45
Author(s):  
Elpida Piperopoulos ◽  
Luigi Calabrese ◽  
Emanuela Mastronardo ◽  
Edoardo Proverbio ◽  
Candida Milone
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Oil Recovery ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
High Stress ◽  
Absorption Capacity ◽  
Simplified Approach ◽  
Composite Foams

This paper studies the correlation between oil recovery usability and mechanical behavior under compression loads of an innovative oil recovery material. The examined composites are silicone foams filled with carbon nanotubes (CNT). Here, the reutilization of oil recovery processes of the newly developed composite foams is evaluated. In this regard, static and cyclic compressive tests are carried out. Samples filled with pristine and functionalized CNT are tested to evaluate the influence of the filler’s characteristics on the composite foam’s mechanical behavior. The results show that the presence of CNT (CNT-0) increases the elastic modulus (0.030 MPa) and collapse stress (0.010 MPa) of the siloxane matrix. On the contrary, as the CNT functionalization degree increases, a worsening of the composite’s mechanical performance is observed. CNT-0 foam evidences, also, the optimal mechanical stability to cyclic compressive loads, maintaining high stress values until 30 cycles. Furthermore, a correlation between the absorption capacity, elastic modulus, and cyclability is reported, highlighting a simplified approach to tailor the high absorption durability performance of filled CNT silicone foams. The promising results confirm the possible reuse of these new composite foams as absorbent materials for oil spill recovery applications.

scholarly journals Mechanical performance of HMA-2 modified with purified and unpurified carbon nanotubes and nanofibers

2017 ◽  
Vol 37 (2) ◽  
pp. 99-106
Author(s):  
Mario Rodrigo Rubio ◽  
Duván Julián Martínez ◽  
Carlos Enrique Daza ◽  
Fredy Alberto Reyes
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Elastic Modulus ◽  
Mechanical Performance ◽  
Resilient Modulus ◽  
Type Ii ◽  
Dynamic Characterization ◽  
Traffic Loads ◽  
Nickel Copper

The present study evaluates the mechanical performance of a Hot Mix Asphalt – Type II (HMA-2) modified with carbon nanotubes and carbon nanofibers (CNTF). CNTF were made by means the Catalytic Vapor Deposition (CVD) technique at 700° C using a Nickel, Copper and Aluminum (NiCuAl) catalyst with a Cu/Ni molar relation of 0,33. In order to properly assess HMA-2 performance, three different mixtures were analyzed: 1) HMA-2 modified with purified CNTF; 2) HMA-2 modified with non-purified CNTF and, 3) a Conventional HMA-2 (control). Samples manufactured in accordance with the Marshall Mix Design were tested in the laboratory to study rutting, resilient modulus (Mr) and fatigue. In addition to the aforementioned dynamic characterization, the effect of CNTF purification on the asphalt mixture’s mechanical properties was analyzed. In short, a comparative study was designed to determine whether or not CNTF should be purified before introduction into the HMA-2. This investigation responds to the growing demand for economical materials capable of withstanding traffic loads while simultaneously enhancing pavement durability and mechanical properties. Although purified CNTF increased HMA-2 stiffness and elastic modulus, non-purified CNTF increased the asphalt mixture’s elastic modulus without considerable increases in stiffness. Thus, the latter modification is deemed to help address fatiguerelated issues and improve the long-term durability of flexible pavements.

scholarly journals Thermal and hydraulic effects on the mechanical behavior of coarse-grained soils used as heat storage media

2021 ◽  
Vol 337 ◽  
pp. 01023
Author(s):  
Henok Hailemariam ◽  
Frank Wuttke
Keyword(s):  
Mechanical Behavior ◽  
Heat Storage ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Storage System ◽  
Ground Level ◽  
Coarse Grained ◽  
Careful Study ◽  
Storage Media ◽  
Below Ground

Assessing the mechanical stability of soils used as heat storage media is vital in the design and wellbeing of sensible heat storage systems, which are typically designed below ground level or as part of the sub-structure of buildings with load bearing capabilities and subjected to frequent water table fluctuations. Nevertheless, considering the importance that moisture and temperature factors have in building a mechanically sound heat storage media, a careful study of such effects has not been given adequate attention in past studies. On this basis, the mechanical performance of two heat storage sandy soils at different moisture contents and temperature conditions is studied in this research. The results show a significant dependence of the mechanical behavior of the investigated soils on moisture content and temperature, which when unaccounted for can result in the inaccurate design of the overall storage system.

scholarly journals A Combination of Enhanced Mechanical and Electromagnetic Shielding Properties of Carbon Nanotubes Reinforced Cu-Ni Composite Foams

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1772
Author(s):  
Dan Wang ◽  
Zhong Wu ◽  
Fengxian Li ◽  
Xueping Gan ◽  
Jingmei Tao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Heat Treatments ◽  
Absorption Capacity ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Chemical Plating ◽  
Composite Foams ◽  
Uniform Dispersion ◽  
Shielding Properties

Carbon nanotubes (CNTs) reinforced double-layered Cu-Ni composite foams (Cu-Ni/CNT foams) were prepared through chemical plating and electrodeposition, for the purpose of combining enhanced mechanical and electromagnetic shielding properties. The microstructure characterization revealed a quite uniform dispersion of the CNTs embedded in the metal layers, even after heat treatments. The property testing showed the compressive strength, energy absorption capacity and electromagnetic shielding effectiveness (SE) of Cu-Ni/CNTs foams were significantly improved, as compared to Cu-Ni foams. The heat treatments of the composite foams resulted in an interdiffusion of the Cu and Ni layers, causing an increase of compressive strength and a slight decrease of average SE. The possible mechanisms of the property evolution are discussed.

scholarly journals Effects of drying and shrinkage on the mechanical performance of unsaturated fine/medium- grained soils used as heat storage media

2021 ◽  
Vol 337 ◽  
pp. 01022
Author(s):  
Henok Hailemariam ◽  
Frank Wuttke
Keyword(s):  
Energy Storage ◽  
Mechanical Behavior ◽  
Elevated Temperatures ◽  
Heat Storage ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Storage Systems ◽  
Storage System ◽  
Energy Storage Systems ◽  
Storage Media

Studying the mechanical behavior of heat storage media is vital in the safety and design of most sensible and borehole thermal energy storage systems, which are normally built as part of the sub-structure of buildings with load bearing capabilities. In spite of its importance on the efficiency and performance of heat energy storage systems, the mechanical stability and behavior of heat storage materials, mainly at elevated temperatures, has not been given adequate attention in past studies. On this regard, the mechanical behavior of three unsaturated fine- and medium- grained soils from Germany is studied at elevated temperatures, in view of using the soils as a solid sensible heat storage media. The results show a significant dependence of the mechanical behavior of the investigated soils on moisture content and temperature. Furthermore, an increase in shrinkage of the soil specimens with a decrease in the texture of the soils was observed during heating of the soils. The shrinkage behavior is also corroborated with the formation of minor and moderate tensile desiccation cracks of the specimens, which when unaccounted for can result in the lowering of the heat conduction of the heat storage medium, thus lowering the efficiency of the heat storage system.

Effect Mechanisms of Carbon Nanotubes on the Supercritical Foaming Behaviors and Mechanical Performance of Carbon Foam

2011 ◽  
Vol 26 (10) ◽  
pp. 1020-1024
Author(s):  
Ying BAO ◽  
Chun-Xiao WANG ◽  
Liang ZHAN ◽  
Yan-Li WANG ◽  
Guang-Zhi YANG ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mechanical Performance ◽  
Carbon Foam ◽  
Supercritical Foaming

Facile Synthesis of Cu2O nanoparticle-loaded Carbon Nanotubes Composite Catalysts for Reduction of 4-Nitrophenol

2020 ◽  
Vol 16 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Yao Feng ◽  
Ran Wang ◽  
Juanjuan Yin ◽  
Fangke Zhan ◽  
Kaiyue Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mechanical Stability ◽  
Catalytic Reduction ◽  
High Surface ◽  
High Surface Area ◽  
Reduction Reaction ◽  
Cycle Performance ◽  
Simple Method ◽  
Composite Catalysts ◽  
Cu2o Nanoparticles

Background: 4-nitrophenol (4-NP) is one of the pollutants in sewage and harmful to human health and the environment. Cu is a non-noble metal with catalytic reduction effect on nitro compounds, and.has the advantages of simple preparation, abundant reserves, and low price. Carbon nanotubes (CNT) are widely used for substrate due to their excellent mechanical stability and high surface area. In this study, a simple method to prepare CNT-Cu2O by controlling different reaction time was reported. The prepared nanocomposites were used to catalyze 4-NP. Methods: CNTs and CuCl2 solution were put into a beaker, and then ascorbic acid and NaOH were added while continuously stirring. The reaction was carried out for a sufficiently long period of time at 60°C. The prepared samples were dried in a vacuum at 50°C for 48 h after washing with ethyl alcohol and deionized water. Results: Nanostructures of these composites were characterized by scanning electron microscope and transmission electron microscopy techniques, and the results at a magnification of 200 nanometers showed that Cu2O was distributed on the surface of the CNTs. In addition, X-ray diffraction was performed to further confirm the formation of Cu2O nanoparticles. The results of ultraviolet spectrophotometry showed that the catalytic effect of the compound on 4-NP was obvious. Conclusions: CNTs acted as a huge template for loading Cu2O nanoparticles, which could improve the stability and cycle performance of Cu2O. The formation of nanoparticles was greatly affected by temperature and the appropriate concentration, showing great reducibility for the 4-NP reduction reaction.

scholarly journals Carbon Nanotubes and Polydopamine Modified Poly(dimethylsiloxane) Sponges for Efficient Oil–Water Separation

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2431
Author(s):  
Wen Zhang ◽  
Juanjuan Wang ◽  
Xue Han ◽  
Lele Li ◽  
Enping Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Large Scale ◽  
Absorption Capacity ◽  
Potential Candidate ◽  
Hard Template ◽  
Water Separation ◽  
Industrial Oil ◽  
The Matrix ◽  
Oil Water Separation ◽  
Oil Water

In this paper, effective separation of oil from both immiscible oil–water mixtures and oil-in-water (O/W) emulsions are achieved by using poly(dimethylsiloxane)-based (PDMS-based) composite sponges. A modified hard template method using citric acid monohydrate as the hard template and dissolving it in ethanol is proposed to prepare PDMS sponge composited with carbon nanotubes (CNTs) both in the matrix and the surface. The introduction of CNTs endows the composite sponge with enhanced comprehensive properties including hydrophobicity, absorption capacity, and mechanical strength than the pure PDMS. We demonstrate the successful application of CNT-PDMS composite in efficient removal of oil from immiscible oil–water mixtures within not only a bath absorption, but also continuous separation for both static and turbulent flow conditions. This notable characteristic of the CNT-PDMS sponge enables it as a potential candidate for large-scale industrial oil–water separation. Furthermore, a polydopamine (PDA) modified CNT-PDMS is developed here, which firstly realizes the separation of O/W emulsion without continuous squeezing of the sponge. The combined superhydrophilic and superoleophilic property of PDA/CNT-PDMS is assumed to be critical in the spontaneously demulsification process.

scholarly journals Mechanical and thermal stability of retained austenite in plastically deformed bainite-based TRIP-aided medium-Mn steels

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Ulrich Krupp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Retained Austenite ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Cost Effective ◽  
Tensile Tests ◽  
Thermal Stability Of

AbstractAdvanced medium-Mn sheet steels show an opportunity for the development of cost-effective and light-weight automotive parts with improved safety and optimized environmental performance. These steels utilize the strain-induced martensitic transformation of metastable retained austenite to improve the strength–ductility balance. The improvement of mechanical performance is related to the tailored thermal and mechanical stabilities of retained austenite. The mechanical stability of retained austenite was estimated in static tensile tests over a wide temperature range from 20 °C to 200 °C. The thermal stability of retained austenite during heating at elevated temperatures was assessed by means of dilatometry. The phase composition and microstructure evolution were investigated by means of scanning electron microscopy, electron backscatter diffraction, X-ray diffraction and transmission electron microscopy techniques. It was shown that the retained austenite stability shows a pronounced temperature dependence and is also stimulated by the manganese addition in a 3–5% range.

Dynamic Strain Effects in Elastomers

1963 ◽  
Vol 36 (2) ◽  
pp. 407-421 ◽  
Author(s):  
Glenn E. Warnaka
Keyword(s):  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Strain Amplitude ◽  
Loss Factor ◽  
Dynamic Strain ◽  
Dynamic Mechanical ◽  
Small Strains ◽  
Dynamic Mechanical Behavior ◽  
Elastomeric Materials ◽  
Practical Engineering

Abstract Many common elastomeric materials have two ranges of dynamic-mechanical behavior. Such materials behave as viscoelastomers at very small strains and as plastoelastomers at strains of practical engineering interest. The change from viscoelastic to plastoelastic behavior occurs at dynamic strain amplitudes of 0.001 inches per inch to 0.005 inches per inch. In the plastoelastic range, the dynamic elastic modulus decreases with increasing dynamic strain amplitude. Loss factor reaches a maximum in the plastoelastic range.

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