scholarly journals Obtaining and characterizing biodegradable composites from agroenergetic residues

2021 ◽  
Vol 19 (1) ◽  
pp. 01-13
Author(s):  
Hélida Cristina Noronha Figueiredo ◽  
Juan Carlos Valdés Serra ◽  
Marcus Vinicius Ribeiro e Souza
Keyword(s):  
Castor Oil ◽  
Room Temperature ◽  
Morphological Analysis ◽  
Preparation Method ◽  
Low Cost ◽  
Synthetic Fibers ◽  
Biodegradable Composites ◽  
Biodegradable Composite ◽  
The Matrix ◽  
Matrix Reinforcement

The study aimed to produce biodegradable composite materials from sugar cane straw and castor oil-based resin. The fibers were used in two sizes: 0 <fibers ≤4.27mm and 4.27 <fibers <10mm; resin in the proportion of 10%, 15% and 20%. The preparation method was carried out according to NBR 14810-2: 2018, using the compression molding technique at room temperature. Physical assays were carried out: moisture and swelling; mechanical assays: static bending and compression. The morphological assay was evaluated: scanning electron microscopy; and the composite biodegradability assay, over a three-month period. In order to validate the results, the statistic graphic was performed with significance at 5% by the F test, compared to the means by the Scott-knott test of the physical and mechanical treatments. The results showed that the values of the physical assays have met the minimum limits established by the standard, resulting in 8.72% swelling of the composite material. In the mechanical assay, the composite with less fiber and 20% resin was more resistant in the bend test with a capacity of 3.69 N/mm², and in the compression assay with 2.98 N/mm². The morphological analysis showed a wide interaction at the matrix/reinforcement interface. The biodegradation assay showed that over the months the composites started to lose weight, which shows the improvement of the degradation. Therefore, the composite produced has great potential in the market, it is considered biodegradable and of low cost compared to composites produced from synthetic fibers.

Biodegradable Composites Applied to the Automotive Industry: The Development of a Loudspeaker Front

2008 ◽  
Vol 587-588 ◽  
pp. 187-191 ◽  
Author(s):  
Ana Rita Campos ◽  
António M. Cunha ◽  
Alberto Tielas ◽  
António Mateos
Keyword(s):  
Automotive Industry ◽  
Testing Machine ◽  
Environmental Legislation ◽  
Electron Microscopies ◽  
Biodegradable Composites ◽  
Morphological Aspects ◽  
The Matrix ◽  
Twin Screw ◽  
Moulding Machine ◽  
Matrix Reinforcement

The interest of the automotive industry on biodegradable and green composites is increasing dramatically due two environmental legislation that obliges automakers to reduce the disposal of waste from vehicles [1]. As an answer to this recent demand several research groups are working on the development of these composites. This work shows the development of a loudspeaker front made of two different biodegradable composites: PLA (polylactic acid) and SCA (blend of starch and cellulose acetate) reinforced with different percentages of cellulose spent fibres. The composites were previously extruded on a counter-rotating twin screw extruder and injection moulded into tensile specimens. The mechanical properties of the produced tensile specimens were assessed with an Instron Universal Testing Machine as well as the morphological aspects of the materials, studied with optical and scanning electron microscopies. After these preliminary set of tests, the best composites were chosen to produce the final parts (loudspeaker front). These parts were injection moulded on a Ferromatik Milacron K85 injection moulding machine (850 kN clamping force) and subjected to a wide set of automotive tests to evaluate their performance. The best materials for this application proved to be the PLA reinforced composites, although there is still a large window for improvement of properties, based on the engineering of the matrix/reinforcement interface and also on the improvement of the thermal properties of the PLA material.

scholarly journals Natural Vegetable Fibre / Plasticised Natural Vegetable Fibre - a Candidate for Low Cost and Fully Biodegradable Composite

1999 ◽  
Vol 8 (5) ◽  
pp. 096369359900800 ◽  
Author(s):  
Xun Lu ◽  
Ming Qiu Zhang ◽  
Min Zhi Rong ◽  
Guang Shi ◽  
Gui Cheng Yang ◽  
...  
Keyword(s):  
Fibre Composite ◽  
Low Cost ◽  
Natural Fibre ◽  
Pine Sawdust ◽  
Natural Fibre Composite ◽  
Biodegradable Composite ◽  
Fibre Composites ◽  
Heterogeneous Nature ◽  
The Matrix ◽  
Vegetable Fibre

A novel fibre composite consisting of natural vegetable fibre as the reinforcer and plasticised natural vegetable fibre as the matrix was studied. By means of cyanoethylation and chlorination, pine sawdust and chopped sisal were converted into thermoplastics and then compounded with sisal and ramie fibres. The natural fibre composite not only exhibits properties similar to those of conventional fibre composites, but also is characterised by easy processing, enviromental frendliness, low cost and capability of tailoring property due to the physically heterogeneous nature.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

ALCHEMI of B2-Ordered Fe50Al45Me5 alloys

1996 ◽  
Vol 54 ◽  
pp. 548-549
Author(s):  
Ian M. Anderson
Keyword(s):  
Room Temperature ◽  
Iron Aluminide ◽  
Low Density ◽  
Intermetallic Alloys ◽  
Practical Applications ◽  
Alloying Additions ◽  
Site Distribution ◽  
Good Corrosion Resistance ◽  
Room Temperature Ductility ◽  
The Matrix

B2-ordered iron aluminide intermetallic alloys exhibit a combination of attractive properties such as low density and good corrosion resistance. However, the practical applications of these alloys are limited by their poor fracture toughness and low room temperature ductility. One current strategy for overcoming these undesirable properties is to attempt to modify the basic chemistry of the materials with alloying additions. These changes in the chemistry of the material cannot be fully understood without a knowledge of the site-distribution of the alloying elements. In this paper, the site-distributions of a series of 3d-transition metal alloying additions in B2-ordered iron aluminides are studied with ALCHEMI.A series of seven alloys of stoichiometry Fe50AL45Me5, with Me = {Ti, V, Cr, Mn, Co, Ni, Cu}, were prepared with identical heating cycles. Microalloying additions of 0.2% B and 0.1% Zr were also incorporated to strengthen the grain boundaries, but these alloying additions have little influence on the matrix chemistry and are incidental to this study.

The butterfly martensite nucleation in an iron and nickel alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 906-907
Author(s):  
Q.Z. Chen ◽  
X.F. Wu ◽  
T. Ko
Keyword(s):  
Nickel Alloy ◽  
Ethyl Alcohol ◽  
Dislocation Structure ◽  
Martensite Transformation ◽  
Room Temperature ◽  
The Matrix

Some butterfly martensite nuclei were observed in an Fe-27.6Ni-0.89V-0.05C alloy. The alloy was austenitized at 1200°C for 1 hour. Some samples were aged at 850° C for 40 minutes and quenched in 10% brine at room temperature. All the samples were cooled in ethyl alcohol for martensite transformation.A nucleus in an unaged specimen is shown in Fig.1. The nucleus has certain contrast different from the matrix and is shaped like one wing of a butter fly martensite. The SADP of the circled region is measured to be: da=dh, and approximate to dγ(111) and dm(110) with ∠AOB = 55° . It is similar to [011]f.c.c and b patterns in the anglez ∠AOB and the ratio ra/rb, respectively. The SADP shows that the structure of the nucleus is between f.c.c and b.c.c. The dislocation structure within the nucleus is shown in Fig.2. Their Burgers vectors and line directions are also given in it. There are many long dislocations near it without dislocations piled up as shown in Fig.3.Long dislocations are closed at one end as an envelope.

To Eliminate Curtain Effect of FIB TEM Samples by a Combination of Sample Dicing and Backside Milling

2014 ◽  
Author(s):  
Jian-Shing Luo ◽  
Hsiu Ting Lee
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Preparation Method ◽  
Low Cost ◽  
Ion Beam ◽  
Sample Preparation Method ◽  
Site Specific ◽  
Dual Beam ◽  
Transmission Electron

Abstract Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.

Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long
Keyword(s):  
Electrochemical Sensor ◽  
Molecular Imprinting ◽  
Neurological Disorders ◽  
Room Temperature ◽  
Low Cost ◽  
Differential Pulse ◽  
Current Response ◽  
Specific Selectivity ◽  
Pulse Voltammetry

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

Single–atom manganese and nitrogen co-doped graphene as low-cost catalysts for the efficient CO oxidation at room temperature

2021 ◽  
Vol 536 ◽  
pp. 147809
Author(s):  
Mingming Luo ◽  
Zhao Liang ◽  
Chao Liu ◽  
Xiaopeng Qi ◽  
Mingwei Chen ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Room Temperature ◽  
Low Cost ◽  
Single Atom ◽  
Doped Graphene ◽  
Co Doped

scholarly journals Room-Temperature Solution-Processed 0D/1D Bilayer Electrodes for Translucent CsPbBr3 Perovskite Photovoltaics

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1489
Author(s):  
Bhaskar Parida ◽  
Saemon Yoon ◽  
Dong-Won Kang
Keyword(s):  
Solar Cells ◽  
Indium Tin Oxide ◽  
High Performance ◽  
Room Temperature ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Ambient Air ◽  
Plasma Damage ◽  
Temperature Solution ◽  
Ito Nanoparticles

Materials and processing of transparent electrodes (TEs) are key factors to creating high-performance translucent perovskite solar cells. To date, sputtered indium tin oxide (ITO) has been a general option for a rear TE of translucent solar cells. However, it requires a rather high cost due to vacuum process and also typically causes plasma damage to the underlying layer. Therefore, we introduced TE based on ITO nanoparticles (ITO-NPs) by solution processing in ambient air without any heat treatment. As it reveals insufficient conductivity, Ag nanowires (Ag-NWs) are additionally coated. The ITO-NPs/Ag-NW (0D/1D) bilayer TE exhibits a better figure of merit than sputtered ITO. After constructing CsPbBr3 perovskite solar cells, the device with 0D/1D TE offers similar average visible transmission with the cells with sputtered ITO. More interestingly, the power conversion efficiency of 0D/1D TE device was 5.64%, which outperforms the cell (4.14%) made with sputtered-ITO. These impressive findings could open up a new pathway for the development of low-cost, translucent solar cells with quick processing under ambient air at room temperature.

scholarly journals Enhanced Oil Removal by a Non-Toxic Biosurfactant Formulation

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 467
Author(s):  
Emília Mendes da Silva Santos ◽  
Isabela Regina Alvares da Silva Lira ◽  
Hugo Moraes Meira ◽  
Jaciana dos Santos Aguiar ◽  
Raquel Diniz Rufino ◽  
...  
Keyword(s):  
Room Temperature ◽  
Low Cost ◽  
Aeration Rate ◽  
Oil Removal ◽  
Central Composite Rotatable Design ◽  
Chemical Methods ◽  
Ph Values ◽  
Spectroscopic Analyses ◽  
New Formulation ◽  
Central Composite

In this study, a new formulation of low-cost, biodegradable, and non-toxic biosurfactant by Candida sphaerica UCP 0995 was investigated. The study was conducted in a bioreactor on an industrial waste-based medium, and a central composite rotatable design was used for optimization. The best results, namely a 25.22 mN/m reduction in surface tension, a biosurfactant yield of 10.0 g/L, and a critical micelle concentration of 0.2 g/L, were achieved in 132 h at an agitation speed of 175 rpm and an aeration rate of 1.5 vvm. Compositional and spectroscopic analyses of the purified biosurfactant by chemical methods, Fourier transform infrared spectroscopy, and nuclear magnetic resonance suggested that it is a glycolipid-type biosurfactant, and it showed no cytotoxicity in the MTT assay. The biosurfactant, submitted to different formulation methods as a commercial additive, remained stable for 120 days at room temperature. Tensioactive properties and stability were evaluated at different pH values, temperatures, and salt concentrations. The biosurfactant obtained with all formulation methods demonstrated good stability, with tolerance to wide ranges of pH, temperature and salinity, enabling application under extreme environmental conditions. Bioremediation tests were performed to check the efficacy of the isolated biosurfactant and the selected microbial species in removing oil from soil. The results demonstrated that the biosurfactant produced has promising properties as an agent for the bioremediation of contaminated soil.

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