scholarly journals Dielectric Behavior and Morphostructural Characteristics of Some HDPE Composites / Metal Nanopowders

2019 ◽  
Vol 56 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Alina-Ruxandra Caramitu ◽  
Sorina Mitrea ◽  
Virgil Marinescu ◽  
George-Andrei Ursan ◽  
Mihaela Aradoaie ◽  
...  
Keyword(s):  
Dielectric Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Dielectric Behavior ◽  
Sem Images ◽  
Low Frequencies ◽  
High Frequencies ◽  
Metal Filler ◽  
Powder Filler ◽  
Composite Samples

HDPE composite samples with aluminum and iron nanopowders were made by extrusion and injection. Samples of material obtained were characterized by comparative determinations of dielectric spectroscopy and SEM microscopy. SEM images have indicated that the agglomerations of the powders used are persistent, do not decompose during extrusion and injection processing. Determinations by dielectric spectroscopy indicated that HDPE composite materials with metal nanopowder filler have higher dielectric losses than pure HDPE (reference). The highest increases in tgd up to 2.6 times, were recorded for 50 nm nanopowders with specific high surface area (over 20 m2 / g). The electrical conductivity of the investigated samples increases with increasing frequency, both for pure HDPE and for HDPE with metal powder filler. As a result of the film effect in the HDPE case with metal filler, the increases in the high frequencies range are lower than in the extremely low frequencies range.

scholarly journals Amorphous Mo5O14-Type/Carbon Nanocomposite with Enhanced Electrochemical Capability for Lithium-Ion Batteries

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 8 ◽  
Author(s):  
Ahmed M. Hashem ◽  
Ashraf E. Abdel-Ghany ◽  
Rasha S. El-Tawil ◽  
Sylvio Indris ◽  
Helmut Ehrenberg ◽  
...  
Keyword(s):  
Oxygen Deficiency ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Carbon Matrix ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Thermal Gravimetry ◽  
Type C ◽  
Carbon Nanocomposite

An amorphous MomO3m−1/carbon nanocomposite (m ≈ 5) is fabricated from a citrate–gel precursor heated at moderate temperature (500 °C) in inert (argon) atmosphere. The as-prepared Mo5O14-type/C material is compared to α-MoO3 synthesized from the same precursor in air. The morphology and microstructure of the as-prepared samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering (RS) spectroscopy. Thermal gravimetry and elemental analysis indicate the presence of 25.8 ± 0.2% of carbon in the composite. The SEM images show that Mo5O14 is immersed inside a honeycomb-like carbon matrix providing high surface area. The RS spectrum of Mo5O14/C demonstrates an oxygen deficiency in the molybdenum oxide and the presence of a partially graphitized carbon. Outstanding improvement in electrochemical performance is obtained for the Mo5O14 encapsulated by carbon in comparison with the carbon-free MoO3.

Synthesis and Characterizations of MOF-199 Using PODFA as Porogen for CO2 Adsorption Applications

2016 ◽  
Vol 694 ◽  
pp. 44-49
Author(s):  
Nurfatihah Mahadi ◽  
Halina Misran ◽  
S.Z. Othman
Keyword(s):  
Fatty Alcohol ◽  
Palm Oil ◽  
Carbon Capture ◽  
Metal Organic Framework ◽  
High Surface ◽  
High Surface Area ◽  
Product Formation ◽  
Carbon Chain Length ◽  
Sem Images ◽  
Structure Directing Agent

Copper-based metal-organic framework (MOF-199, also known as Cu-BTC and HKUST-1) materials were successfully synthesized by hydrothermal method using renewable straight-chain fatty alcohol with eight carbon chain length (i.e. octyl alcohol). The addition of palm oil derived fatty alcohol (PODFA) was suggested to act as porogen (structure directing agent) that aided the particle formation and flexible porous structure. This synthesis approach was environmental-friendly and sustainable by utilizing the fatty alcohols originated from biomass such as palm oil. The resulting MOF-199 materials exhibited single crystalline octahedral morphology structure by X-ray diffraction analyses and SEM images. The optimum ratio of octyl alcohol exhibited well-defined single octahedral particles at size range of ca. 10-50 µm and reduced by-product formation of cuprous oxide at high temperature synthesis. The nature of MOF-199 having apparently high surface area, high pore volume and low density provided the possibility in carbon capture storage. The CO2 adsorption capacity of MOF-199 investigated using high pressure volumetric analyser (HPVA-II) at ambient temperature (i.e. 25 °C) was found to be at maximum working capacity.

Predicting acoustic performance of high surface area particle stacks with a poro-elastic model

2021 ◽  
Vol 263 (3) ◽  
pp. 3523-3529
Author(s):  
Zhuang Mo ◽  
Guochenhao Song ◽  
J. Stuart Bolton ◽  
Seungkyu Lee ◽  
Yongbeom Seo
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Biot Theory ◽  
Elastic Model ◽  
Acoustic Behavior ◽  
Unknown Parameters ◽  
Low Frequencies ◽  
Fitting Procedure

Because of the high sound absorption they offer at low frequencies, there is a growing interest in high surface area particles and how they might be applied in noise control. Therefore, a model that can accurately predict the acoustic behavior of this type of materials will be useful in relevant applications. A poro-elastic model based on a combination of Biot theory and an existing rigid model of granular activated carbon (GAC) is introduced in the current work. The input parameters for this model consist of a certain number of properties that are known by measurement, and a set of values obtained by matching the model prediction with acoustic measurements. Measured absorption coefficients and surface impedance of stacks of several types of different activated carbon particles are shown in this paper. A fitting procedure that determines the unknown parameters is also described. It is shown that the model is able to predict the acoustic behavior of the particle stacks, and especially to capture the frame resonances at low frequencies, thus, validating the proposed model. Beyond the activated carbon used in the present tests, it is reasonable to generalize this model to stacks of other high surface area particles.

scholarly journals Experimental Investigation into the Structural and Functional Performance of Graphene Nano-Platelet (GNP)-Doped Asphalt

2019 ◽  
Vol 9 (4) ◽  
pp. 686 ◽  
Author(s):  
Murryam Hafeez ◽  
Naveed Ahmad ◽  
Mumtaz Kamal ◽  
Javaria Rafi ◽  
Muhammad Haq ◽  
...  
Keyword(s):  
Functional Performance ◽  
Permanent Deformation ◽  
High Surface ◽  
Asphalt Binder ◽  
High Surface Area ◽  
Adhesive Bond ◽  
Structural Performance ◽  
Complete Analysis ◽  
Skid Resistance ◽  
Sem Images

With the increase in the demand for bitumen, it has become essential for pavement engineers to ensure that construction of sustainable pavements occurs. For a complete analysis of the pavement, both its structural and functional performances are considered. In this study, a novel material (i.e., Graphene Nano-Platelets (GNPs)) has been used to enhance both of the types of pavements’ performances. Two percentages of GNPs (i.e., 2% and 4% by the weight of the binder) were used for the modification of asphalt binder in order to achieve the desired Performance Grade. GNPs were homogeneously dispersed in the asphalt binder, which was validated by Scanning Electron Microscope (SEM) images and a Hot Storage Stability Test. To analyze the structural performance of the GNPs-doped asphalt, its rheology, resistance to permanent deformation, resistance to moisture damage, and bitumen-aggregate adhesive bond strength were studied. For the analysis of the functional performance, the skid resistance and polishing effect were studied using a British Pendulum Skid Resistance Tester. The results showed that GNPs improved not only the rutting resistance of the pavement but also its durability. The high surface area of GNPs increases the pavement’s bonding strength and makes the asphalt binder stiffer. GNPs also provide nano-texture to the pavement, which enhances its skid resistance. Thus, we can recommend GNPs as an all-around modifier that could improve not only the structural performance but also the functional performance of asphalt pavements.

scholarly journals High Photocatalytic Activity under Visible Light for a New Morphology of Bi2WO6 Microcrystals

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 667 ◽  
Author(s):  
Campos ◽  
Nobre ◽  
Filho ◽  
Ribeiro da Silva ◽  
Costa ◽  
...  
Keyword(s):  
Single Phase ◽  
High Surface ◽  
High Surface Area ◽  
Orthorhombic Phase ◽  
Xrd Analysis ◽  
High Photocatalytic Activity ◽  
Sem Images ◽  
Bismuth Tungstate ◽  
Adsorption Desorption ◽  
Dye Solutions

In this work, a new morphology was obtained for bismuth tungstate (Bi2WO6-glyc) using a hydrothermal method with the addition of glycerol as a surfactant. In order to compare, the bismuth tungstate without glycerol as the surfactant, i.e., Bi2WO6, was synthesized. Structural characterization by XRD and Rietveld refinement confirmed the orthorhombic structure as a single phase for all samples with high crystallinity. All active modes in Raman spectroscopy for the orthorhombic phase of bismuth tungstate were confirmed in agreement with XRD analysis. N2 adsorption/desorption and size pore distribution confirmed the high surface area (85.7 m2/g) for Bi2WO6-glyc when compared with Bi2WO6 (8.5 m2/g). The optical band gap by diffuse reflectance was 2.78 eV and 2.88 eV for Bi2WO6-glyc and Bi2WO6, respectively. SEM images confirmed the different morphology for these materials, and microstructures with cheese crisp were observed for Bi2WO6-glyc (cheese crisp). On the other hand, flower-like microcrystals were confirmed for Bi2WO6 sample. The photocatalytic performance of Bi2WO6-glyc (94.2%) in the photodegradation of rhodamine B (RhB) dye solutions at 60 min was more expressive than Bi2WO6 (81.3%) and photolysis (8.2%) at 90 min.

scholarly journals Manufacturing and Assessment of Electrospun PVP/TEOS Microfibres for Adsorptive Heat Transformers

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 443 ◽  
Author(s):  
Patrizia Frontera ◽  
Mikio Kumita ◽  
Angela Malara ◽  
Junya Nishizawa ◽  
Lucio Bonaccorsi
Keyword(s):  
Thermal Stability ◽  
High Surface ◽  
High Surface Area ◽  
High Permeability ◽  
Sem Images ◽  
Good Thermal Stability ◽  
Adsorption Heat Pump ◽  
High Flexibility ◽  
Woven Textile ◽  
Thermal Stability Of

A new adsorbent coating for the adsorber unit of an adsorption heat pump made of hybrid, organic–inorganic microfibres was prepared and characterized. Different coatings were obtained by the electrospinning of polyvinylpyrrolidone (PVP) solutions added with different quantities of tetraethyl orthosilicate (TEOS). PVP is a polymer with water adsorption capability and the TEOS addition allowed to increase the thermal stability of microfibres. The aim, indeed, was to preserve the polymeric structure of microfibres in order to obtain coatings with high flexibility and mechanical strength. The results demonstrated that TEOS concentrations in the range of 5–13 wt.% produced microfibre coatings of non-woven textile structure with both good water affinity and good thermal stability. SEM images of coatings showed that the deposited microfibre layers have both a high surface area and a high permeability representing a significant advantage in adsorption systems.

scholarly journals Automated Nanofiber Diameter Measurement in SEM Images Using a Robust Image Analysis Method

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ertan Öznergiz ◽  
Yasar Emre Kiyak ◽  
Mustafa E. Kamasak ◽  
Isa Yildirim
Keyword(s):  
Image Analysis ◽  
Fiber Diameter ◽  
High Surface ◽  
High Surface Area ◽  
Real Data ◽  
Average Fiber Diameter ◽  
Diameter Measurement ◽  
Sem Images ◽  
Human Errors ◽  
Nanofiber Diameter

Due to the high surface area, porosity, and rigidity, applications of nanofibers and nanosurfaces have developed in recent years. Nanofibers and nanosurfaces are typically produced by electrospinning method. In the production process, determination of average fiber diameter is crucial for quality assessment. Average fiber diameter is determined by manually measuring the diameters of randomly selected fibers on scanning electron microscopy (SEM) images. However, as the number of the images increases, manual fiber diameter determination becomes a tedious and time consuming task as well as being sensitive to human errors. Therefore, an automated fiber diameter measurement system is desired. In the literature, this task is achieved by using image analysis algorithms. Typically, these methods first isolate each fiber in the image and measure the diameter of each isolated fiber. Fiber isolation is an error-prone process. In this study, automated calculation of nanofiber diameter is achieved without fiber isolation using image processing and analysis algorithms. Performance of the proposed method was tested on real data. The effectiveness of the proposed method is shown by comparing automatically and manually measured nanofiber diameter values.

scholarly journals Δ-FeOOH as Support for Immobilization Peroxidase: Optimization via a Chemometric Approach

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 259 ◽  
Author(s):  
Tássia Silva Tavares ◽  
Eduardo Pereira da Rocha ◽  
Francisco Guilherme Esteves Nogueira ◽  
Juliana Arriel Torres ◽  
Maria Cristina Silva ◽  
...  
Keyword(s):  
High Efficiency ◽  
Immobilized Enzyme ◽  
High Surface ◽  
High Surface Area ◽  
Sem Images ◽  
X Ray ◽  
Independent Variables ◽  
Surface Iron ◽  
Chemometric Approach ◽  
Optimized Conditions

Owing to their high surface area, stability, and functional groups on the surface, iron oxide hydroxide nanoparticles have attracted attention as enzymatic support. In this work, a chemometric approach was performed, aiming at the optimization of the horseradish peroxidase (HRP) immobilization process on Δ-FeOOH nanoparticles (NPs). The enzyme/NPs ratio (X1), pH (X2), temperature (X3), and time (X4) were the independent variables analyzed, and immobilized enzyme activity was the response variable (Y). The effects of the factors were studied using a factorial design at two levels (−1 and 1). The biocatalyst obtained was evaluated for the ferulic acid (FA) removal, a pollutant model. The materials were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The SEM images indicated changes in material morphology. The independent variables X1 (−0.57), X2 (0.71), and X4 (0.42) presented the significance effects estimate. The variable combinations resulted in two significance effects estimates, X1*X2 (−0.57) and X2*X4 (0.39). The immobilized HRP by optimized conditions (X1 = 1/63 (enzyme/NPs ratio, X2 = pH 8, X4 = 60 °C, and 30 min) showed high efficiency for FA oxidation (82%).

Structural Modification of Polymer Nanocomposites Based on Tetrazole

2016 ◽  
Vol 723 ◽  
pp. 459-463
Author(s):  
Evgeniy N. Lushin ◽  
Rene Alejandro Castro
Keyword(s):  
Dielectric Permittivity ◽  
Potassium Chloride ◽  
Specific Conductivity ◽  
Structural Features ◽  
Potassium Nitrate ◽  
Dielectric Behavior ◽  
Low Frequencies ◽  
Polymeric Systems ◽  
High Frequencies ◽  
Degree Of Dissociation

Structural features and dielectric behavior of polymeric systems based on tetrazole are investigated after combining them with potassium nitrate (KNO3) and potassium chloride (KCl). It was found that the salt additives added to the system exist in the form of the singular crystallites that is the closed inclusions chaotically distributed inside polymeric matrix. Injection of potassium nitrate increases the value of dielectric permittivity on the studied interval of frequencies. Potassium chloride reduces the value of dielectric permittivity of the polymeric system in the field of high frequencies, and increases it in the field of low frequencies. Addition of salt increases the specific conductivity of composites that indicates increase in degree of dissociation of ionogenic substances. In the studied systems, ionogenic substances, besides salt additives, including water and remains of catalysts.

Synthesis of Kapok (Ceiba pentandra) Carbon Sponges for Recovery of Oil and Organic Solvents

2021 ◽  
Vol 880 ◽  
pp. 127-132
Author(s):  
Wayne Christian P. Datiles ◽  
Sellina M. Sy ◽  
Mary Donnabelle L. Balela
Keyword(s):  
Oil Spills ◽  
High Surface ◽  
High Surface Area ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Sem Images ◽  
Water Contact ◽  
Cellulosic Fibers ◽  
Kapok Fibers ◽  
Increasing Temperature

Extensive processes and costly precursors for the fabrication of existing sorbents for oil spills urges to look for more renewable sorbent sources. In this work, hollow, tubular, cellulosic fibers (kapok, Ceibapentandra) were successfully converted to carbon sponges by pyrolysis at increasing temperature and time. Fourier Transform Infrared (FTIR) spectroscopy confirmed the complete carbonization of the kapok fibers at 800 °C. Scanning Electron Microscope (SEM) images revealed that the carbonized kapok fibers maintained their original tubular structures, suggesting high surface area. Water contact angle measurement showed improved hydrophobicity, with a maximum value of about 135°. The carbonized fibers were able to hold selected organic and oil solvents ranging from 16-20 times the weight of the fibers. The fiber pyrolyzed at 400 °C for 0.5 h showed the highest sorption capacity at 45.56 g/g for palm oil, almost matching that of raw kapok.

Sign in / Sign up

Export Citation Format

Share Document