scholarly journals Influence of Carbon Nanosheets on the Behavior of 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine Langmuir Monolayers

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 94 ◽  
Author(s):  
Ruth Muñoz-López ◽  
Eduardo Guzmán ◽  
Maria Mercedes Velázquez ◽  
Laura Fernández-Peña ◽  
María Dolores Merchán ◽  
...  
Keyword(s):  
Carbon Nanomaterials ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Lung Surfactant ◽  
Langmuir Monolayers ◽  
Interfacial Area ◽  
Carbon Nanosheets ◽  
Inhaled Particles ◽  
Lipid Adsorption ◽  
Main Component

Carbon nanomaterials are widespread in the atmospheric aerosol as a result of the combustion processes and their extensive industrial use. This has raised many question about the potential toxicity associated with the inhalation of such nanoparticles, and its incorporation into the lung surfactant layer. In order to shed light on the main physical bases underlying the incorporation of carbon nanomaterials into lung surfactant layers, this work has studied the interaction at the water/vapor interface of carbon nanosheets (CN) with Langmuir monolayers of 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC), with this lipid being the main component of lung surfactant layers and responsible of some of the most relevant features of such film. The incorporation of CN into DPPC Langmuir monolayers modifies the lateral organization of the DPPC at the interface, which is explained on the basis of two different effects: (i) particles occupy part of the interfacial area, and (ii) impoverishment of the lipid composition of the interface due to lipid adsorption onto the CN surface. This results in a worsening of the mechanical performance of the monolayers which may present a negative impact in the physiological performance of lung surfactant. It would be expected that the results obtained here can be useful as a step toward the understanding of the most fundamental physico-chemical bases associated with the effect of inhaled particles in the respiratory cycle.

scholarly journals Interaction of Particles with Langmuir Monolayers of 1,2-Dipalmitoyl-Sn-Glycero-3-Phosphocholine: A Matter of Chemistry?

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 469 ◽  
Author(s):  
Eduardo Guzmán ◽  
Eva Santini ◽  
Michele Ferrari ◽  
Libero Liggieri ◽  
Francesca Ravera
Keyword(s):  
Mechanical Performance ◽  
Lung Surfactant ◽  
Langmuir Monolayers ◽  
Tear Film ◽  
Potential Health ◽  
Specific Chemical ◽  
Physico Chemical ◽  
Pressure Area ◽  
The Impact ◽  
Lipid Layers

Lipid layers are considered among the first protective barriers of the human body against pollutants, e.g., skin, lung surfactant, or tear film. This makes it necessary to explore the physico-chemical bases underlying the interaction of pollutants and lipid layers. This work evaluates using a pool of surface-sensitive techniques, the impact of carbon black and fumed silica particles on the behavior of Langmuir monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). The results show that the incorporation of particles into the lipid monolayers affects the surface pressure–area isotherm of the DPPC, modifying both the phase behavior and the collapse conditions. This is explained considering that particles occupy a part of the area available for lipid organization, which affects the lateral organization of the lipid molecules, and consequently the cohesion interactions within the monolayer. Furthermore, particles incorporation worsens the mechanical performance of lipid layers, which may impact negatively in different processes presenting biological relevance. The modification induced by the particles has been found to be dependent on their specific chemical nature. This work tries to shed light on some of the most fundamental physico-chemical bases governing the interaction of pollutants with lipid layers, which plays an essential role on the design of strategies for preventing the potential health hazards associated with pollution.

scholarly journals Assessment of the mercury contamination of landfilled and recovered foundry waste – a case study

2021 ◽  
Vol 19 (1) ◽  
pp. 462-470
Author(s):  
Marta Bożym ◽  
Beata Klojzy-Karczmarczyk
Keyword(s):  
Negative Impact ◽  
Mercury Content ◽  
Mercury Contamination ◽  
Reference Level ◽  
Organic Carbon Content ◽  
Foundry Sands ◽  
Industrial Sites ◽  
Different Types ◽  
Main Component

Abstract Environmental pollution by mercury is a local problem in Poland and concerns mainly industrial sites. Foundry waste are usually characterized by low mercury content compared to other heavy metals. Spent foundry sands with low content of Hg are the main component of foundry waste. However, Hg may be present in foundry dust, which may also be landfilled. Due to Hg toxicity, even a minimal content may have a negative impact on biota. This study focuses on assessing the mercury content of landfilled foundry waste (LFW), to assess its toxicity. Currently tested waste is recovered and reused as a road aggregate. The results were compared with the mercury content of local soils as the reference level. Waste samples were taken from foundry landfill. The mercury content, fractional composition, organic matter (OM) and total organic carbon content, pH and elementary composition of waste were analysed. It was found that the mercury content in LFW was very low, at the level of natural content in soils and did not pose a threat to the environment. The statistical analysis shows that mercury was not associated with OM of the waste, in contrast to soils, probably due to different types of OM in both materials.

scholarly journals Nonuniform Woven Solar Shading Screens: Shading, Mechanical, and Daylighting Performance

2019 ◽  
Vol 11 (20) ◽  
pp. 5652 ◽  
Author(s):  
Yao Lu ◽  
Hankun Lin ◽  
Siwei Liu ◽  
Yiqiang Xiao
Keyword(s):  
Solar Radiation ◽  
Mechanical Performance ◽  
Structural Strength ◽  
Negative Impact ◽  
Optical Performance ◽  
Clear View ◽  
Performance Factors ◽  
Ansys Simulation ◽  
Solar Shading ◽  
Optimal Configurations

This study investigated the potential of using a nonuniform woven panel with nonuniform strips—thick sticks and thin battens—as an external solar shading screen that addressed daylighting, shading, and mechanical performance factors. The sustainable material, namely, bamboo, was used as the demonstration material for the screen. An on-site experiment and ANSYS simulation were carried out to investigate the basic solar optical performance and structural strength of the proposed screen, respectively. Then, a series of daylighting simulations were conducted to optimize the configuration of the screen. The results showed that the nonuniform woven solar shading screen reduced up to 80.3% of the solar radiation gain in a room during summer months while ensuring a relatively even distribution of useful daylight during the year. Moreover, the screen effectively reduced the negative impact of glare to a level below “imperceptible” and enabled a relatively clear view through the window and shading. Regarding the structural strength, the screen with a size smaller than or equal to 1 × 1 m withstood a wind load of 12 m/s. Furthermore, this study proposed two optimal configurations: a screen woven of square sticks and battens with a distance of 10 mm between them, and a screen woven of round sticks and battens with a distance of 8 mm between them. This study illustrated the superiority of the nonuniform woven solar shading screens, which supports a wider application of solar shading screens made of other materials with similar structures and reflectance values.

scholarly journals A Study on the Effect of Carbon Nanotubes’ Distribution and Agglomeration in the Free Vibration of Nanocomposite Plates

2020 ◽  
Vol 6 (4) ◽  
pp. 79
Author(s):  
D. S. Craveiro ◽  
M. A. R. Loja
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Properties ◽  
Natural Frequencies ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Free Vibrations ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Agglomeration Effect ◽  
Performance Predictions

The present work aimed to characterize the free vibrations’ behaviour of nanocomposite plates obtained by incorporating graded distributions of carbon nanotubes (CNTs) in a polymeric matrix, considering the carbon nanotubes’ agglomeration effect. This effect is known to degrade material properties, therefore being important to predict the consequences it may bring to structures’ mechanical performance. To this purpose, the elastic properties’ estimation is performed according to the two-parameter agglomeration model based on the Eshelby–Mori–Tanaka approach for randomly dispersed nano-inclusions. This approach is implemented in association with the finite element method to determine the natural frequencies and corresponding mode shapes. Three main agglomeration cases were considered, namely, agglomeration absence, complete agglomeration, and partial agglomeration. The results show that the agglomeration effect has a negative impact on the natural frequencies of the plates, regardless the CNTs’ distribution considered. For the corresponding vibrations’ mode shapes, the agglomeration effect was shown in most cases not to have a significant impact, except for two of the cases studied: for a square plate and a rectangular plate with symmetrical and unsymmetrical CNTs’ distribution, respectively. Globally, the results confirm that not accounting for the nanotubes’ agglomeration effect may lead to less accurate elastic properties and less structures’ performance predictions.

scholarly journals Sustainable Development of Carbon Nanocomposites: Synthesis and Classification for Environmental Remediation

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Dhinakaran Veeman ◽  
M. Varsha Shree ◽  
P. Sureshkumar ◽  
T. Jagadeesha ◽  
L. Natrayan ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Carbon Nanomaterials ◽  
Mechanical Performance ◽  
Hydrogen Sensors ◽  
Processing Technologies ◽  
Solar Hydrogen ◽  
Carbon Nanocomposites ◽  
Methods Of Synthesis ◽  
Carbon Nanocomposite ◽  
Made In

Composite materials with carbon nanotube and graphene attachments have been regarded as promising prospects. Carbon nanocomposites have gained considerable interest in different fields including biomedical applications due to its exceptional structural dimensions and outstanding mechanical, electrical, thermal, optical, and chemical characteristics. The significant advances made in carbon nanocomposite over past years along with the discovery of new nanocomposite processing technologies to improvise the functional impact of nanotube and graphene composites by providing proper methods of synthesis and improving the production of diverse composite based on carbon nanomaterials are discussed. Carbon nanocomposites are applied in various fields such as aviation, batteries, chemical industry, fuel cell, optics, power generation, space, solar hydrogen, sensors, and thermoelectric devices. The recent design, fabrication, characteristics, and applications of carbon nanocomposites such as active carbon, carbon black, graphene, nanodiamonds, and carbon nanotubes are explained in detail in this research. It is found that unlike traditional fiber composites, Van der Waals force interfacial compounds have an important effect on the mechanical performance of carbon nanomaterial-based composites.

scholarly journals Investigation of the mechanical and thermal characteristics of an eco-insulating material made of plaster and date palm fibers

2021 ◽  
Vol 16 (2) ◽  
pp. 55-66
Author(s):  
Mokhtar Rachedi ◽  
Abdelouahed Kriker
Keyword(s):  
Building Materials ◽  
Date Palm ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Low Cost ◽  
Natural Fibers ◽  
Thermal Characteristics ◽  
Chemical Degradation ◽  
Date Palm Fibers

Abstract The negative impact of the production and use of building materials on the environment has become evident, so in recent decades, to find more sustainable, eco-friendly, and low-cost materials, the last research tends to reconsider the use of natural fibers and traditional building materials. This paper aims to develop a bio-composite based on the southern Algerian region's local materials consisting mainly of plaster and waste from date palm trees. Many properties were examined experimentally through previous research of our team (physical, mechanical, and microstructure characteristics) [1, 2] to characterize these materials. Several samples of bio-composite of plaster configurations with short length (20mm) and eight-weight ratios (0.5% - 4%) of palm fibers were prepared for mechanical, thermal, and physical characterizations. In addition, tested all previous properties on the specimens after 28 days of curing in normal conditions. The results show a clear improvement in the bio-composites mechanical performance (an increase in the bending strength with achieving compressive strength) and their thermal properties, which have been well developed (density, thermal conductivity, and specific heat capacity). To enhance the resistance of palm fibers to chemical degradation in the plaster's alkaline environment and improve the adhesion between them, these fibers were treated with a NaOH solution of 1% concentration. The plaster's composites reinforced with date palm fibers can be qualified as eco-friendly and thermal insulation building materials.

scholarly journals Concrete with Partial Substitution of Waste Glass and Recycled Concrete Aggregate

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 430
Author(s):  
Jawad Ahmad ◽  
Rebeca Martínez-García ◽  
Jesús de-Prado-Gil ◽  
Kashif Irshad ◽  
Mohammed A. El-Shorbagy ◽  
...  
Keyword(s):  
Performance Test ◽  
Coarse Aggregate ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Strength Properties ◽  
Waste Glass ◽  
Recycled Concrete ◽  
Partial Substitution ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate

The current practice of concrete is thought to be unsuitable because it consumes large amounts of cement, sand, and aggregate, which causes depletion of natural resources. In this study, a step towards sustainable concrete was made by utilizing recycled concrete aggregate (RCA) as a coarse aggregate. However, researchers show that RCA causes a decrease in the performance of concrete due to porous nature. In this study, waste glass (WG) was used as a filler material that filled the voids between RCA to offset its negative impact on concrete performance. The substitution ratio of WG was 10, 20, or 30% by weight of cement, and RCA was 20, 40, and 60% by weight of coarse aggregate. The slump cone test was used to assess the fresh property, while compressive, split tensile, and punching strength were used to assess the mechanical performance. Test results indicated that the workability of concrete decreased with substitution of WG and RCA while mechanical performance improved up to a certain limit and then decreased due to lack of workability. Furthermore, a statical tool response surface methodology was used to predict various strength properties and optimization of RCA and WG.

scholarly journals Thermo-mechanical characterization of a bio-composite mortar reinforced with date palm fiber

2020 ◽  
Vol 15 ◽  
pp. 155892502094823
Author(s):  
Samir Benaniba ◽  
Zied Driss ◽  
Mokhtar Djendel ◽  
Elhadj Raouache ◽  
Rabah Boubaaya
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Building Materials ◽  
Date Palm ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Natural Fibers ◽  
Palm Fiber ◽  
Date Palm Fibers

Due to respect for the environment and the search for more sustainable materials, scientists have started in recent decades to launch studies on bio-composite materials. It is well known that building materials are among the most commonly used materials and have an obvious negative impact on the environment. The development of environmentally friendly composites as insulating materials in buildings offers practical solutions to reduce energy consumption. Therefore, this work presents the use of a new bio-composite material composed of natural fibers, date palm fibers, cement, and sand. In addition, the study on the effect of adding date palm fibers on the thermo-mechanical characteristics of mortars assesses the thermal insulation properties as well as the water absorption and mechanical performance of this new bio-composite material to use it in the construction of buildings. The percentage by weight of date palm fiber in the test samples varied from 0% to 30% for a fiber size of length equal to 7 mm. The characteristics of these samples were determined experimentally in terms of resistance to bending and compression as well as thermal conductivity. The results show that while increasing the weight of date palm fiber, an obviously reduction in thermal conductivity, flexural, and compressive strength of the composite is observed. Hence, date palm fiber has a positive effect on the thermo-mechanical properties of the composite material. Therefore, it considerably improves the insulating capacity of the mortar.

scholarly journals Study of 1D and 2D Carbon Nanomaterial in Alginate Films

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 206 ◽  
Author(s):  
Beatriz Salesa ◽  
Mar Llorens-Gámez ◽  
Ángel Serrano-Aroca
Keyword(s):  
Cell Adhesion ◽  
Mammalian Cells ◽  
Carbon Nanomaterials ◽  
Mechanical Performance ◽  
Composite Films ◽  
Antibacterial Properties ◽  
Skin Wound ◽  
Biological Behavior ◽  
Great Promise ◽  
Skin Wound Healing

Alginate-based materials hold great promise in bioengineering applications such as skin wound healing and scaffolds for tissue engineering. Nevertheless, cell adhesion of mammalian cells on these hydrophilic materials is very poor. In cases such as polycaprolactone, poly(hydroxy-3-butyrate-co-3-valerate) and gelatin, the incorporation of hydrophobic carbon nanofibers (CNFs) and hydrophilic graphene oxide (GO) has shown significant improvement of cell adhesion and proliferation. The incorporation of these carbon nanomaterials (CNMs) into alginate films can enhance their mechanical performance, wettability, water diffusion and antibacterial properties. Herein, we report the effect of adding these CNMs into alginate films on cell adhesion for the first time. Thus, the results of this study showed that these nanocomposites are non-cytotoxic in human keratinocyte HaCaT cells. Nevertheless, contrary to what has been reported for other polymers, cell adhesion on these advanced alginate-based composites was not improved. Therefore, both types of composite films possess similar biological behavior, in terms of cell adhesion and non-cytotoxicity, and enhanced physical and antibacterial properties in comparison to neat alginate for potential biomedical and bioengineering applications.

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