scholarly journals Rheological, Mechanical and Morphological Characterization of Fillers in the Nautical Field: The Role of Dispersing Agents on Composite Materials

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1339 ◽  
Author(s):  
Silvia Vita ◽  
Rico Ricotti ◽  
Andrea Dodero ◽  
Silvia Vicini ◽  
Per Borchardt ◽  
...  
Keyword(s):  
External Surface ◽  
Morphological Characterization ◽  
Point Of View ◽  
Morphological Properties ◽  
Filler Materials ◽  
Efficient Tool ◽  
Hollow Glass Microspheres ◽  
Dispersing Agents

Coatings have a fundamental role in covering the external surface of yachts by acting both as protective and aesthetic layers. In particular, fillers represent the essential layer from the point of view of mechanical properties and consist of a polymeric matrix, different extenders and additives, and dispersing agents, with the latter having the role to provide good extender-matrix compatibility. In the present work, the effects of dispersing agents with an ionic or steric action on the interactions between hollow glass microspheres and an epoxy-polyamide resin are evaluated. Un-crosslinked filler materials are studied via rheological tests, whereas the mechanical and morphological properties of the crosslinked samples are assessed. The results clearly indicate that steric dispersing agents provide a much greater compatibility effect compared to ionic ones, owing to their steric hindrance capability, thus leading to better-performing filler materials with a less-marked Payne effect, which is here proved to be an efficient tool to provide information concerning the extent of component interactions in nautical fillers. To the best of our knowledge, this work represents the first attempt to deeply understand the role of dispersing agents, which are until now empirically used in the preparation of fillers.

Bentonite-Based Organoclays as Innovative Flame Retardants Agents for SBS Copolymer

2008 ◽  
Vol 8 (12) ◽  
pp. 6316-6324 ◽  
Author(s):  
M. Comes Franchini ◽  
P. Fabbri ◽  
A. Frache ◽  
G. Ori ◽  
M. Messori ◽  
...  
Keyword(s):  
Flame Retardants ◽  
Morphological Characterization ◽  
Tem Analysis ◽  
Important Functional Property ◽  
Octadecyltrimethylammonium Bromide ◽  
Nitrogen Containing Compounds ◽  
Styrene Butadiene ◽  
Heat Released

Two organophilic bentonites, based on nitrogen-containing compounds, have been synthesised via ion exchange starting from pristine bentonite with octadecyltrimethylammonium bromide (OTAB) and with synthetic melamine-derived N2,N4-dihexadecyl-1,3,5-triazine-2,4,6-triamine (DEDMEL). The chemical and morphological characterization of the organoclays was based on XRD, TEM, Laser Granulometry, X-Ray Fluorescence and CEC capacity. Copoly(styrene-butadiene-styrene)-nanocomposites (SBS-nanocomposites) were obtained by intercalation of the SBS-copolymer into these new organoclays by melt intercalation method. XRD and TEM analysis of the organoclays and of the micro/nano-composites obtained are presented. The effect of the organoclays on the SBS-nanocomposite's flammability properties was investigated using cone calorimeter. An encouraging decrease of 20% in the peak heat released rate (PHRR) has been obtained confirming the important role of melamine's based skeleton and its derived organoclays to act as effective fire retardants and for the improvement of this important functional property in SBS copolymers.

scholarly journals Morphological characterization of gram-positive and gram-negative bacteria from treated latex processing wastewater

2021 ◽  
Vol 1 (2) ◽  
pp. 32-36
Author(s):  
Farrah Aini Dahalan ◽  
Nor Azizah Parmin
Keyword(s):  
Oxygen Demand ◽  
Morphological Characterization ◽  
The Other ◽  
Morphological Properties ◽  
Morphological Observation ◽  
Gram Positive ◽  
Bacterial Colony ◽  
Gram Negative ◽  
Gram Staining

A preliminary morphological screening and isolation of bacterial colony from latex industrial wastewater was carried out. Bacteria colonies from latex processing wastewater were isolated from a local latex processing industry. It was found that 17 bacterial isolates had been purified grown on nutrient agar under 35˚C. The colonies were then purified and morphologically indicated via Gram staining and motility test. After morphological observation, it was identified that out of 17 isolates, 9 isolates were Gram positive and 8 isolates were Gram negative. There are 11 out of 17 colonies were rod-shaped bacterial colonies, while the other 6 colonies were cocci-shaped bacteria. There were 11 colonies of gliding bacteria, three colonies were non-motile bacteria and the other three colonies were flagellated bacteria. This study is only limited to morphological observation as the main aim of this study was to investigate the potential occurrence of viable growth in treated latex processing wastewater. The bacterial colonies were classified base on their morphological properties shown. This study has classified several genera such as Staphylococcus, Escherichia, Thiobacillus, Arthrobacter and other Genus. The growth curve of 17 isolates studied and the chemical oxygen demand were determined.

scholarly journals Physical and Morphological Characterization of Chitosan/Montmorillonite Films Incorporated with Ginger Essential Oil

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 700 ◽  
Author(s):  
Victor Gomes Lauriano Souza ◽  
João Ricardo Afonso Pires ◽  
Carolina Rodrigues ◽  
Patricia Freitas Rodrigues ◽  
Andréia Lopes ◽  
...  
Keyword(s):  
Essential Oil ◽  
Uv Light ◽  
Barrier Properties ◽  
Morphological Characterization ◽  
Morphological Properties ◽  
Unsaturated Fat ◽  
Light Barrier ◽  
Bionanocomposite Films ◽  
Oxidative Processes

Novel bionanocomposite films of chitosan/montmorillonite (CS/MMT) activated with ginger essential oil (GEO) were produced and characterized in terms of their physical and morphological properties. The homogenization process led to a good interaction between the chitosan and the nanoparticles, however the exfoliation was diminished when GEO was incorporated. Film glass transition temperature did not statistically change with the incorporation of either MMT or GEO, however the value was slightly reduced, representing a relaxation in the polymer chain which corroborated with the mechanical and barrier properties results. Pristine chitosan films showed excellent barrier properties to oxygen with a permeability of 0.184 × 10−16 mol/m·s·Pa being reduced to half (0.098 × 10−16 mol/m·s·Pa) when MMT was incorporated. Although the incorporation of GEO increased the permeability values to 0.325 × 10−16 mol/m·s·Pa when 2% of GEO was integrated, this increment was smaller with both MMT and GEO (0.285 × 10−16 mol/m·s·Pa). Bionanocomposites also increased the UV light barrier. Thus, the produced bioplastics demonstrated their ability to retard oxidative processes due to their good barrier properties, corroborating previous results that have shown their potential in the preservation of foods with high unsaturated fat content.

scholarly journals Adsorption of Cellulase on Wrinkled Silica Nanoparticles with Enhanced Inter-Wrinkle Distance

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1799
Author(s):  
Aniello Costantini ◽  
Virginia Venezia ◽  
Giulio Pota ◽  
Aurelio Bifulco ◽  
Valeria Califano ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Morphological Characterization ◽  
Operational Stability ◽  
Successful Outcome ◽  
Glucose Yield ◽  
Transmission Electron ◽  
Ft Ir ◽  
Immobilized Cellulase

Mesoporous silica materials offer a unique opportunity for enzyme immobilization thanks to their properties, such as tuneable pore size, large surface area and easy functionalization. However, a significant enhancement of cellulase enzyme activity entrapped inside the silica pores still represents a challenge. In this work, we immobilized cellulase by adsorption on wrinkled silica nanoparticles (WSNs), obtaining an active and stable biocatalyst. We used pentanol as co-solvent to synthesize WSNs with enhanced inter-wrinkle distance in order to improve cellulase hosting. The physical-chemical and morphological characterization of WSNs and cellulase/WSNs was performed by thermogravimetric (TG), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM) analyses. The obtained results showed that this matrix generates a favourable microenvironment for hosting cellulase. The results of the catalytic assays and operational stability confirmed the key role of size, morphology and distribution of the pores in the successful outcome of the cellulase immobilization process. The immobilization procedure used allowed preserving most of the secondary structure of the enzyme and, consequently, its catalytic activity. Moreover, the same value of glucose yield was observed for five consecutive runs, showing a high operational stability of the biocatalyst.

Physiological and Morphological Characterization of Local Interneurons in the Drosophila Antennal Lobe

2010 ◽  
Vol 104 (2) ◽  
pp. 1007-1019 ◽  
Author(s):  
Yoichi Seki ◽  
Jürgen Rybak ◽  
Dieter Wicher ◽  
Silke Sachse ◽  
Bill S. Hansson
Keyword(s):  
Antennal Lobe ◽  
Neural Circuit ◽  
Three Dimensional ◽  
Morphological Characterization ◽  
Morphological Properties ◽  
Electrophysiological Properties ◽  
Local Interneurons ◽  
Enhancer Trap Line ◽  
Almost All

The Drosophila antennal lobe (AL) has become an excellent model for studying early olfactory processing mechanisms. Local interneurons (LNs) connect a large number of glomeruli and are ideally positioned to increase computational capabilities of odor information processing in the AL. Although the neural circuit of the Drosophila AL has been intensively studied at both the input and the output level, the internal circuit is not yet well understood. An unambiguous characterization of LNs is essential to remedy this lack of knowledge. We used whole cell patch-clamp recordings and characterized four classes of LNs in detail using electrophysiological and morphological properties at the single neuron level. Each class of LN displayed unique characteristics in intrinsic electrophysiological properties, showing differences in firing patterns, degree of spike adaptation, and amplitude of spike afterhyperpolarization. Notably, one class of LNs had characteristic burst firing properties, whereas the others were tonically active. Morphologically, neurons from three classes innervated almost all glomeruli, while LNs from one class innervated a specific subpopulation of glomeruli. Three-dimensional reconstruction analyses revealed general characteristics of LN morphology and further differences in dendritic density and distribution within specific glomeruli between the different classes of LNs. Additionally, we found that LNs labeled by a specific enhancer trap line (GAL4-Krasavietz), which had previously been reported as cholinergic LNs, were mostly GABAergic. The current study provides a systematic characterization of olfactory LNs in Drosophila and demonstrates that a variety of inhibitory LNs, characterized by class-specific electrophysiological and morphological properties, construct the neural circuit of the AL.

scholarly journals Morphological characterization of seeds in Portulacaceae

Phytotaxa ◽  
2013 ◽  
Vol 141 (1) ◽  
pp. 1 ◽  
Author(s):  
Gilberto Ocampo
Keyword(s):  
Cell Walls ◽  
Individual Cell ◽  
Morphological Diversity ◽  
Morphological Characterization ◽  
Seed Morphology ◽  
Important Variation ◽  
Species Complexes ◽  
Multiple Samples

Portulacaceae is a monogeneric family with around 100 species distributed around the world. Seed morphology is diverse in this group, and its variation has been used for taxonomic and identification purposes. However, documentation of seed morphology has focused on a few species complexes or has been limited to specific countries and geographic areas. Moreover, the terminology employed in different investigations is heterogeneous, thus complicating analyses of seed morphological diversity in Portulacaceae. In this study, the seed morphology of 58 samples representing 49 species, 9 subspecies, and 2 cultivars of Portulaca was documented with the use of scanning electron microscopy (SEM). Based on the examination of the resulting images, a set of morphological features for describing the general shape of the seeds and their individual cell features is proposed; in addition, morphological descriptions for all taxa included in this study are provided. The results indicate that the shape of the seeds was constant within species, contrary to the characters that describe individual cell features, which showed important variation even within the same seed sample. In particular, the outline of the cells and the curvature of the anticlinal cell walls (ACW) were very variable, so a combination of character states was needed to describe the overall diversity of a sample. Conversely, the relief of the periclinal cell walls (PCW) was relatively constant throughout the seeds of the same species, but the relief of the cells of the lateral and peripheral faces was dissimilar in a number of taxa. In addition, other studies provide evidence that the relief of the PCW may vary in widely distributed species. Increased taxon sampling and multiple samples of species with wide geographical ranges will facilitate the study of patterns of variation, and may provide insights into the role of environmental variables on seed diversity of Portulacaceae.

scholarly journals CHARACTERIZATION OF PROCESSES INVOLVED IN THE RESET OF A SUBTIDAL BAR

2012 ◽  
Vol 1 (33) ◽  
pp. 101
Author(s):  
Brice Blossier ◽  
Christophe Brière ◽  
J.A. Roelvink ◽  
D.J.R. Walstra
Keyword(s):  
Wave Breaking ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Study Data ◽  
Point Of View ◽  
Longshore Current ◽  
External Conditions ◽  
Incident Wave Energy

Sand beach profiles can exhibit nearshore sandbars with complex 3D patterns. Under energetic conditions, these patterns disappear and the bars get to a certain extent alongshore uniform. This phenomenon is called a reset. The existing literature mainly concerns the development of the bar patterns (3D) or the cross-shore migration of sandbars (2D). Studies on reset-events from a three dimensional point of view are limited but can be found for instance in Reniers et al. (2004) and Smit (2010). This paper describes an analysis that is aimed at determining the relevant processes involved in the reset of three dimensional subtidal bars and at describing the relative influence of each of these processes. To perform this study, data collected during the ECORS campaign at Le Truc Vert (France) in 2008 are analyzed. In addition, a numerical approach is performed using a research Delft3D model forced by the Xbeach wave generator to investigate the processes involved in a reset-event. The effects of the hydrodynamic external conditions on the flow patterns in the surfzone are investigated. Then the reset is studied in details in order to understand the role of the different processes taken into account by the numerical model. The incident wave energy controls the intensity of the reset. The bar cross-shore migration is controlled by the wave breaking process. The wave breaking position and the dissipation rate of the roller energy controls the generation of Shoreward Propagating Accretionary Waves (SPAW). The straightening of the subtidal bar occurs when the conditions induce a significant longshore current in the surfzone.

Preparation and characterization of biopolymer nanocomposites from cellulose nanofibrils and nanoclays

2017 ◽  
Vol 52 (5) ◽  
pp. 689-700 ◽  
Author(s):  
Gulyaz Al ◽  
Deniz Aydemir ◽  
Bulent Kaygin ◽  
Nadir Ayrilmis ◽  
Gokhan Gunduz
Keyword(s):  
Thermal Analysis ◽  
Polylactic Acid ◽  
Cellulose Nanofibrils ◽  
Tensile Modulus ◽  
Morphological Characterization ◽  
Morphological Properties ◽  
Screw Extruder ◽  
Twin Screw ◽  
Thermal Stability Of

The aim of this study was to investigate the effects of cellulose nanofibrils and nanoclays on the mechanical, thermal, and morphological properties of polyhydroxybutyrate and polylactic acid bio-polymers. Polyhydroxybutyrate and polylactic acid as a polymer matrix and nanoclays and cellulose nanofibrils as reinforcing nano-fillers were used to prepare the biopolymer nanocomposites in twin screw extruder. Density, flexure strength and flexure modulus, tensile strength and tensile modulus, impact strength, thermal properties, and morphological characterization of the obtained biopolymer nanocomposites were determined. According to the obtained results, densities of the biopolymer nanocomposites were found to decrease with addition of the bio-fillers, and it was determined to be decreasing the density due to increasing the porosity in biopolymer nanocomposites. Although the increasing in the porosity of biopolymer nanocomposites was found in scanning electron microscope pictures, the mechanical properties of the biopolymer nanocomposites generally increased as compare with neat bio-polymers. Thermal analysis conducted with thermogravimetric-dynamic thermal analysis and differential scanning calorimeter showed that thermal stability of the biopolymer nanocomposites generally improved according to the neat bio-polymers.

FABRICATION AND OPTICAL AND MORPHOLOGICAL CHARACTERIZATION OF n+-ZnO/i-ZnO AND n+-ZnO/ZnSe BILAYERS USED AS OPTICAL WINDOWS IN SOLAR CELLS

2002 ◽  
Vol 09 (05n06) ◽  
pp. 1617-1621
Author(s):  
C. CALDERÓN ◽  
H. INFANTE ◽  
G. GORDILLO
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Solar Cells ◽  
Morphological Characterization ◽  
Morphological Properties ◽  
Spectral Transmittance ◽  
Optical Window ◽  
Force Microscopy ◽  
Atomic Force

This work presents results concerning the development of n +- ZnO/i-ZnO and n +- ZnO/ZnSe bilayer structures with adequate properties to be used as optical windows in solar cells based on CuInSe 2 thin films. The optical and morphological properties of each of the layers constituting the bilayer structures were studied through spectral transmittance and atomic force microscopy (AFM) measurements. The studies revealed that windows of this type allow a significant increase of the spectral range of absorbed radiation by the solar cell in comparison with those using ZnO/CdS as optical window.

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