Pectin Extraction from Lemon By-product with Acidified Date Juice: Rheological Properties and Microstructure of Pure and Mixed Pectin Gels

2010 ◽  
Vol 16 (2) ◽  
pp. 105-114 ◽  
Author(s):  
M. Masmoudi ◽  
S. Besbes ◽  
I. Ben Thabet ◽  
C. Blecker ◽  
H. Attia
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Rheological Properties ◽  
Gel Formation ◽  
Open Network ◽  
Date Juice ◽  
Pectin Gels ◽  
Scanning Electron

The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties were carried out in the presence of 30%, 45% and 60% sucrose, and increasing calcium concentrations (0-0.1%). The presence of date with lemon pectin led to a gel formation at 45% sucrose and in the presence of calcium, which was not the case for lemon pectin alone under the same conditions. It is suggested that lemon and date pectins interacted, leading to gel formations at different gelling temperatures, which were strongly dependant on degree of methylation. These results were confirmed by scanning electron microscopy, which revealed inhomogeneous gels where dense aggregated network and loose, open network areas were present. Addition of calcium to pectin mixture gels led to stronger and faster gel formation.

The effects of nanoclay on thermal, mechanical and rheological properties of LLDPE/chitosan blend

2017 ◽  
Vol 37 (2) ◽  
pp. 143-149 ◽  
Author(s):  
Sadullah Mir ◽  
Bisma Asghar ◽  
Abida K. Khan ◽  
Rehana Rashid ◽  
Ahson J. Shaikh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Rheological Properties ◽  
Loss Modulus ◽  
Dynamic Shear ◽  
Rheological Characterization ◽  
Scanning Calorimetry ◽  
High Dynamic ◽  
Scanning Electron

Abstract The objective of this study was to prepare linear low density polyethylene (LLDPE)/chitosan/closite nanocomposites by using various concentrations of LLDPE, chitosan, and closite clay mineral. The nanocomposites were then characterized for their thermal, mechanical, and rheological properties by using different analytical techniques including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), rheological characterization, tensile strength study, and scanning electron microscopy. The TGA demonstrated that crosslinked composites are thermally more stable than non-crosslinked composites. The DSC stated that the percentage crystallinity of crosslinked composites is lower than the non-crosslinked composites. It is also observed that the increasing quantity of chitosan and closite also reduces the percentage crystallinity of the prepared nanocomposites. Rheological characterization revealed that, crosslinked composites are viscoelastic in nature and have high complex viscosities (η*) and high dynamic shear storage modulus (G′), while non-crosslinked composites showed high dynamic shear loss modulus (G″). Tensile strength of crosslinked composites was much higher than non-crosslinked composites, however elongation at break (Eb) values of non-crosslinked composites are higher than crosslinked composites. The scanning electron microscopy displayed strong adhesion between matrix-filler-interphase in crosslinked composites, while some gaps were also observed in non-crosslinked composites. As a conclusion, chitosan, closite clay, and the LLDPE based nanocomposites with improved thermal, mechanical, and rheological properties can be successfully prepared by employing a peroxide-initiated melt compounding technique.

Influence of Superplasticizers on the Properties of Lightweight Mortar Plaster Made with Recycled Polymers

2015 ◽  
Vol 1129 ◽  
pp. 546-553 ◽  
Author(s):  
J. Garabito ◽  
Lourdes Alameda ◽  
Jesús Gadea ◽  
Sara Gutiérrez-González
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Rheological Properties ◽  
Ceramic Materials ◽  
Interface Zone ◽  
Hardened State ◽  
Polyamide Powder ◽  
Lightweight Mortar ◽  
Scanning Electron

The advantageous influence of two different polycarboxylate and melamine superplasticizers is studied in relation to the properties of blended mortar plaster made with recycled polymers (polyamide powder and polyurethane foam). The characteristics of the test specimens are defined and tested in both a fresh and a hardened state. The influence of the additives on the microstructure of the lightweight mortar plaster is defined through an analysis of the compatibility of the interface zone of the materials using Fast Scanning Electron Microscopy (FSEM).Our results show that the addition of additives influences the properties of the mortar plaster, enhances its mechanical properties, and increases its adherence with ceramic materials. These results confirm that superplasticizers (depending on the type and dosage) enhance both the properties of the mortar plasters produced with recycled polymers and the rheological properties of the mortars that include polyamide waste.

Compatibilizing Effect of Poly(Styrene-co-Glycidyl Methacrylate) in MPPO/PBT Blend

1998 ◽  
Vol 18 (1-2) ◽  
pp. 101-114 ◽  
Author(s):  
Tae Oan Ahn ◽  
Jae Young Jho ◽  
Soo Young Han ◽  
Han Mo Jeong
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Rheological Properties ◽  
Glycidyl Methacrylate ◽  
Dynamic Mechanical Properties ◽  
Butylene Terephthalate ◽  
Phenylene Oxide ◽  
Compatibilizing Effect ◽  
Scanning Electron

Abstract The compatibilizing effect of three kinds of poly(styrene-co-glycidyl methacrylate) (SGMA) in a modified poly(2,6-dimethyl-1,4-phenylene oxide) (MPPO)/poly(butylene terephthalate) (PBT) blend was studied based on the morphology observed by scanning electron microscopy, dynamic mechanical properties, rheological properties, and mechanical properties. When the content of SGMA in the blend was fixed at 3 phr, the compatibilizing effect of SGMA increased as the GMA content in SGMA was increased. When the content of the reactive GMA monomeric unit in the blend was fixed at 0.37 phr, SGMA containing 4 mol% of GMA unit was most effective for compatibilization among three kinds of SGMAs.

scholarly journals COMPARISON OF SELF-ORGANIZATION PROCESSES IN AQUEOUS SOLUTIONS OF L-CYSTEINE AND N-ACETYL-L-CYSTEINE WITH SILVER NITRITE

2021 ◽  
pp. 56-68
Author(s):  
Татьяна Викторовна Потапенкова ◽  
Дмитрий Викторович Вишневецкий ◽  
Александра Ивановна Иванова ◽  
Светлана Дмитриевна Хижняк ◽  
Павел Михайлович Пахомов
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Light Scattering ◽  
Aqueous Solutions ◽  
Uv Spectroscopy ◽  
Self Organization ◽  
Gel Formation ◽  
Silver Solution ◽  
Scanning Electron

С помощью методов УФ спектроскопии, динамического светорассеяния (ДСР) и сканирующей электронной микроскопии (СЭМ) в водных растворах L-цистеина и N-ацетил-L-цистеина (НАЦ) с нитритом серебра (AgNO) при концентрации от 0.001 М до 0.025 М и различных соотношениях исходных компонентов изучены процессы самоорганизации, приводящие к образованию гидрогеля. Установлено, что для растворов на основе L-цистеин и AgNO (цистеин-серебряный раствор - ЦСР) с концентрацией исходных компонентов 0.025 М и выше образуются устойчивые гидрогели, содержащие наночастицы серебра (НЧС). В то же время, в растворах на основе НАЦ и AgNO гели и НЧС не формировались. Определены закономерности и условия, влияющие на процесс образования геля, что позволило предложить механизм гелеобразования в ЦСР. Using the methods of UV spectroscopy, dynamic light scattering (DLS) and scanning electron microscopy (SEM) in aqueous solutions of L-cysteine and N-acetyl-L-cysteine (NAC) add silver nitrite (AgNO) at different concentration from 0.001 to 0.025 M the processes of self-organization leading to the formation of a hydrogel have studied in various ratios of the initial components. It has found that for solutions based on L-cysteine and AgNO (cysteine-silver solution - CSS) with a concentration of initial components of 0.025 M form stable hydrogels containing silver nanoparticles (SNPs). At the same time, solutions based on NAC and AgNO are unable to form gels and SNPs. The regularities and conditions influencing the process of gel formation have been determined, which made it possible to propose a mechanism of gelation in the CSS.

scholarly journals Preparation and Properties Study of Cementitious Grouts Containing Crumb Rubber

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 555
Author(s):  
Wei Yuan ◽  
Renfeng Yang ◽  
Jianyou Yu ◽  
Shixin Zhou ◽  
Shaoqian Cui ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Strength ◽  
Rheological Properties ◽  
Microwave Treatment ◽  
Crumb Rubber ◽  
Negative Effects ◽  
Scrap Tires ◽  
Scanning Electron ◽  
Optimal Formula

This article aims to improve the toughness of pre-packaged grouts (PPG) by incorporating crumb rubber. The mechanism for toughness of PPG with crumb rubber was analyzed based on the uniaxial compression model. Crumb rubber with surfaces treated by different methods (NaOH solutions or microwave treatment) was observed by scanning electron microscopy (SEM). The effects of mesh sizes, amounts, surface-treated methods of crumb rubber, and mixing procedures on the PPG’s mechanical strength and rheological properties were investigated. The results showed that, firstly, the addition of crumb rubber improves the PPG’s toughness, while its mechanical strength is reduced. Adding NaOH solutions or microwave-treated crumb rubber into PPG can weaken the negative effects of crumb rubber on the PPG’s mechanical strength; however, this function is limited. Secondly, the crumb rubber grouts’ rheological properties can be fully exploited by increasing the stirring rate and time so that the fluidity of crumb rubber grouts is improved, which fulfils the characteristics of no bleeding and micro-expansion. Finally, the optimal formula and mixing technique of crumb rubber grouts were proposed in this paper.The results of this paper can provide a significant reference for the application of scrap tires.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

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