scholarly journals HDPE/SILICA COMPOSITES- PART I: PREPARATION AND CHARACTERIZATION OF METHYLSILANE AND OCTYLSILANE-MODIFIED SILICAS

2019 ◽  
Vol 16 (32) ◽  
pp. 263-278
Author(s):  
Vanessa Machado Babinski RAMOS ◽  
Maurício Gammertt RÖHNELT ◽  
Rodrigo BRAMBILLA
Keyword(s):  
Silica Gel ◽  
Morphological Characteristics ◽  
Specific Area ◽  
Sem Images ◽  
Adsorption Sites ◽  
Pyrogenic Silica ◽  
The Mean ◽  
Complementary Techniques ◽  
Adsorption Desorption

This paper reports the main results concerning the synthesis and characterization of methylsilane and octylsilane-modified silicas. The modification of the silicas with these groups aims to make the silica surface hydrophobic and thus compatible with high-density polyethylene (HDPE) in HDPE/silica composites. In the present work, two types of silica were organofunctionalized: a pyrogenic silica and a silica gel. The silicas were characterized by a series of complementary techniques with the objective of investigating the nature of the surface species and their textural and morphological characteristics. The SEM images showed that the modification of the silicas with organosilanes has been not resulted in changes on the morphology and on the size of silica particles. In relation to the texture properties, determined by N2 adsorption-desorption porosimetry, the silica modification resulted in a decrease of the specific area (SBET) and the mean pore volume, a behavior attributed to the partial coverage of the adsorption sites by the organosilane molecules. The TGA analysis showed that both the methylsilane groups and the octylsilane groups on the surface of silica and silica gel are thermally stable up to 200 ° C, which enables the organofunctionalized silicas in terms of thermal stability, for the process of preparing the composites by extrusion. The results of applying these organofunctionalized silicas in the development of HDPE/silica composites will be presented in a subsequent article, part II of this research.

scholarly journals Extraction and Mass Spectrometric Characterization of Terpenes Recovered from Olive Leaves Using a New Adsorbent-Assisted Supercritical CO2 Process

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1301
Author(s):  
Zully J. Suárez Montenegro ◽  
Gerardo Álvarez-Rivera ◽  
Jose A. Mendiola ◽  
Elena Ibáñez ◽  
Alejandro Cifuentes
Keyword(s):  
Aluminum Oxide ◽  
Silica Gel ◽  
Supercritical Co2 ◽  
Olive Leaves ◽  
Fractionation Process ◽  
Selective Enrichment ◽  
Adsorption Desorption ◽  
First Time ◽  
By Products

This work reports the use of GC-QTOF-MS to obtain a deep characterization of terpenoid compounds recovered from olive leaves, which is one of the largest by-products generated by the olive oil industry. This work includes an innovative supercritical CO2 fractionation process based on the online coupling of supercritical fluid extraction (SFE) and dynamic adsorption/desorption for the selective enrichment of terpenoids in the different olive leaves extracts. The selectivity of different commercial adsorbents such as silica gel, zeolite, and aluminum oxide was evaluated toward the different terpene families present in olive leaves. Operating at 30 MPa and 60 °C, an adsorbent-assisted fractionation was carried out every 20 min for a total time of 120 min. For the first time, GC-QTOF-MS allowed the identification of 40 terpenoids in olive leaves. The GC-QTOF-MS results indicate that silica gel is a suitable adsorbent to partially retain polyunsaturated C10 and C15 terpenes. In addition, aluminum oxide increases C20 recoveries, whereas crystalline zeolites favor C30 terpenes recoveries. The different healthy properties that have been described for terpenoids makes the current SFE-GC-QTOF-MS process especially interesting and suitable for their revalorization.

scholarly journals MICROSTRUCTURAL AND MECHANICAL CHARACTERIZATION OF CONSOLIDATED NANO- AND MICRON- SIZE Cu POWDERS

2012 ◽  
Vol 05 ◽  
pp. 18-23
Author(s):  
A. SALEH ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE ◽  
S. SHEIBANI
Keyword(s):  
Crystallite Size ◽  
Mechanical Characterization ◽  
Sintering Temperature ◽  
Sem Images ◽  
Crystalline Sample ◽  
Nano Crystalline ◽  
Micron Size ◽  
The Mean ◽  
Cold Pressed

In this paper, nano-crystalline Cu powder with a mean crystallite size of 45 nm and commercial micron-size Cu powder were either hot pressed or cold pressed and sintered conventionally to fabricate bulk samples. Hardness, density, crystallite size and microstructure of the samples after consolidation were examined. The results show that the hardness of the hot pressed nano-crystalline Cu is in the range of 0.75-1.2 GPa which is higher than that of commercial Cu . The density of the bulk nano-crystalline sample showed that the rising sintering temperature increases the density up to 97% of the theoretical value. The mean crystallite size of the hot pressed sample was 64 nm, which still was in the nano scale. The scanning electron microscopy (SEM) images revealed that the hot pressed samples contain less porosities compared to the conventionally consolidated samples.

The study on chemical adsorption of dissolved oxygen on naturally formed co-oxides filter film in aqueous solution: combined characterization of XPS and TPD

2014 ◽  
Vol 15 (2) ◽  
pp. 411-420 ◽  
Author(s):  
Tinglin Huang ◽  
Xin Cao ◽  
Gang Wen ◽  
Yingming Guo
Keyword(s):  
Dissolved Oxygen ◽  
Specific Area ◽  
Chemical Effect ◽  
Chemical Adsorption ◽  
Adsorbed Species ◽  
Adsorption Sites ◽  
High Concentrations ◽  
Weak Chemical ◽  
Iron And Manganese

The chemical adsorption of dissolved oxygen (DO) by co-oxide filter film-coated sands, formed through the filtration of ground water containing high concentrations of ammonia, manganese and iron, were studied. The results showed that the filter film consisted of silicates, carbonates, manganese and iron oxides and was constructed in a three-layer porous structure. The specific area of film-coated sands was 6.5 m2/g. The chemical adsorption sites of DO are composed of silicates, iron and manganese atoms, and the adsorption was a weak chemical effect. The O2− is the adsorbed species of DO.

Synthesis and Characterization of an Experimental Zn-Hydroxyapatite Powders with Application in Dentistry

2013 ◽  
Vol 587 ◽  
pp. 43-51 ◽  
Author(s):  
Doina Prodan ◽  
Marioara Moldovan ◽  
Cristina Prejmerean ◽  
Laura Silaghi-Dumitrescu ◽  
Stanca Boboia ◽  
...  
Keyword(s):  
Size Distribution ◽  
Nanometer Scale ◽  
Size Distributions ◽  
Sem Images ◽  
X Ray ◽  
Microstructural Parameters ◽  
Heat Treated ◽  
Different Temperatures ◽  
Adsorption Desorption

In the present study, Zn-hydroxyapatite (Zn-HA) was synthesized, the powder was thermally treated at different temperatures and then characterized. The Zn-HA powder was characterized mainly by FTIR and XRD, but have been performed investigations like SEM, BET and size distribution. The addition of ZnO in hydroxyapatite causes alleged interactions with the existing groups in HA, which amend the corresponding signals to these groups in the IR spectra. X-ray diffractograms for samples (untreated and heat-treated) have been recorded and microstructural parameters for the all samples have been calculated. The obtained average sizes of the crystallites and the network tensions support the idea that Zn-HA powders are nanostructured. The SEM images and size distributions for Zn-HA indicate a cluster of crystals with nanometer-scale of the population-base. Was determined the adsorption-desorption isotherms for Zn-HA powder at 100 o C and 800 o C. The dates obtained from the analysis of particle size distribution indicates for the Zn-HA powder an size distribution for granules in the range from 0.05 to 0.3μm

Synthesis and Characterization of Stable Mesoporous Multilamellar Silica Vesicles

2007 ◽  
Vol 121-123 ◽  
pp. 473-478 ◽  
Author(s):  
Yu Fang Zhu ◽  
Jian Lin Shi ◽  
Wei Hua Shen
Keyword(s):  
Pore Volume ◽  
Specific Area ◽  
Synthesis And Characterization ◽  
N2 Adsorption ◽  
Structure Directing Agent ◽  
Large Pore Volume ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
High Specific Area

A family of mesoporous multilamellar silica vesicles has been successfully synthesized by using P123 as structure directing agent and hexane as co-surfactant. The structure was characterized with XRD, TEM, and N2 adsorption-desorption isotherms. This multilamellar silica vesicle materials process high specific area, large pore volume, and a bimodale pore size distribution. Furthermore, these materials are stable when the surfactant is removed at 530 oC.

scholarly journals Titanium Dioxide and Polyethylmethacrylate electrospun nanofibers: assessing the technique parameters and morphological characterization

2019 ◽  
Vol 22 (1) ◽  
pp. Process ◽  
Author(s):  
Jessica Dias Santos ◽  
Tabata Prado Sato ◽  
Aline Lins de Lima ◽  
Andrea Souza Nogueira ◽  
Cristiane Campos Costa Quishida ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Morphological Characteristics ◽  
Electrospun Nanofibers ◽  
Morphological Characterization ◽  
Electrospinning Technique ◽  
Flow Rates ◽  
X Ray ◽  
Significant Difference ◽  
The Mean

This work studied the synthetization and morphological characterization of Polyethylmethacrylate (PEMA) nanofibers (NFs) containing titanium dioxide (TiO2) produced by the electrospinning technique. The solution to produce the nanofibers was prepared by dissolving 2.5g PEMA in 6.75mL of 1.1.2.2- tetrachloroethane and 3.375mL of dimethylformamide (DMF), and 0.405g of TiO2 was added to the solution. The nanofiber production used different distances between the tip of the needle to the collector (10, 12 and 15 cm) and two flow rates (0.05 mLh-1 and 0.08 mLh-1) were employed, while the applied voltage was 17kV. The NF morphology was analyzed by Scanning Electron Microscopy (SEM) and Image J software. We used Fourier Infrared Spectroscopy (FTIR) and Energy Dispersive X-Ray Spectroscopy (EDS) to evaluate the structural properties. All parameters were effective in the NF production, however it was shown that the distance of 12 cm produced the best NFs. The mean diameters showed no statistically significant difference between the samples. The FTIR analysis showed characteristic peaks of PEMA and TiO2. It was concluded that the employed method was efficient for NF production containing PEMA and TiO2,and the morphological characteristics of the NFs were influenced by the voltage and distance. KeywordsPolymer; Fibers; Electrochemistry.

scholarly journals Morphological characterization of Kielmeyera coriacea Mart. Cork from brazilian Cerrado

CERNE ◽  
2011 ◽  
Vol 17 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Polliana D'Angelo Rios ◽  
Fábio Akira Mori ◽  
Ana Carolina Maioli Campos Barbosa
Keyword(s):  
Cell Walls ◽  
Morphological Characteristics ◽  
Quercus Suber ◽  
Morphological Characterization ◽  
Morphological Aspect ◽  
Brazilian Cerrado ◽  
Growth Season ◽  
Sem Images ◽  
Kielmeyera Coriacea

Kielmeyera coriacea Mart., known as "pau-santo", is mentioned in the literature as the main tree species which produces cork of the Brazilian Cerrado. The purpose of this study was to describe the morphological aspect of Kielmeyera coriacea ("pau-santo") cork cells through its microscopic structure and to compare it with the cellular morphology of Quercus suber (cork oak), which is the main cork producing species worldwide. The bark from three trees of the species Kielmeyera coriacea Mart. was collected randomly at points 1.30 m above the ground, with four repetitions per sample. Samples came from native stands situated in the region of Luminárias - MG, Brazil. The study of morphological characteristics was conducted by counting the number of sides of the cells, and measuring the dimensions of the cells from images obtained by scanning electron microscopy (SEM). Images were analyzed using the LEOUIF software. The distribution in faces and edges of cork cells from Kielmeyera coriacea, was observed to have from 4 to 8 sides, with a predominance of hexagonal cells, similar to Quercus suber. The averages of height and thickness of the cell walls were 40 to 70 µm and 1.5 to 2.0 µm respectively, indicating cells from an early growth season. Both height and thickness were observed to be greater than those present in Quercus suber.

Preparation and Characterization of Biodiesel from Karanja Oil by Using Silica Gel Reactor

2014 ◽  
Author(s):  
Sukanta Mondal ◽  
Kaniz Ferdous ◽  
M. Rakib Uddin ◽  
Maksudur R. Khan ◽  
M. A. Islam ◽  
...  
Keyword(s):  
Silica Gel ◽  
Karanja Oil

Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Block Design ◽  
Coffea Canephora ◽  
Coffee Production ◽  
Randomized Block Design ◽  
Significant Difference ◽  
The Mean ◽  
Four Blocks ◽  
Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

scholarly journals Characterization of a new natural fiber extracted from Corypha taliera fruit

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Taslima Ahmed Tamanna ◽  
Shah Alimuzzaman Belal ◽  
Mohammad Abul Hasan Shibly ◽  
Ayub Nabi Khan
Keyword(s):  
Tensile Strength ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Morphological Characteristics ◽  
Synthetic Fiber ◽  
X Ray Diffraction ◽  
Reinforced Composite ◽  
Potential Alternative

AbstractThis study deals with the determination of new natural fibers extracted from the Corypha taliera fruit (CTF) and its characteristics were reported for the potential alternative of harmful synthetic fiber. The physical, chemical, mechanical, thermal, and morphological characteristics were investigated for CTF fibers. X-ray diffraction and chemical composition characterization ensured a higher amount of cellulose (55.1 wt%) content and crystallinity (62.5%) in the CTF fiber. The FTIR analysis ensured the different functional groups of cellulose, hemicellulose, and lignin present in the fiber. The Scherrer’s equation was used to determine crystallite size 1.45 nm. The mean diameter, specific density, and linear density of the CTF fiber were found (average) 131 μm, 0.86 g/cc, and 43 Tex, respectively. The maximum tensile strength was obtained 53.55 MPa for GL 20 mm and Young’s modulus 572.21 MPa for GL 30 mm. The required energy at break was recorded during the tensile strength experiment from the tensile strength tester and the average values for GL 20 mm and GL 30 mm are 0.05381 J and 0.08968 J, respectively. The thermal analysis ensured the thermal sustainability of CTF fiber up to 230 °C. Entirely the aforementioned outcomes ensured that the new CTF fiber is the expected reinforcement to the fiber-reinforced composite materials.

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