scholarly journals Bacterial Nanocellulose Nitrates

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1694 ◽  
Author(s):  
Vera V. Budaeva ◽  
Yulia A. Gismatulina ◽  
Galina F. Mironova ◽  
Ekaterina A. Skiba ◽  
Evgenia K. Gladysheva ◽  
...  
Keyword(s):  
Materials Science ◽  
Analytical Techniques ◽  
High Viscosity ◽  
Research Area ◽  
Cellulose Content ◽  
Bacterial Nanocellulose ◽  
Mixed Acid ◽  
13C Nuclear Magnetic Resonance ◽  
Freeze Dried ◽  
Application Fields

Bacterial nanocellulose (BNC) whose biosynthesis fully conforms to green chemistry principles arouses much interest of specialists in technical chemistry and materials science because of its specific properties, such as nanostructure, purity, thermal stability, reactivity, high crystallinity, etc. The functionalization of the BNC surface remains a priority research area of polymers. The present study was aimed at scaled production of an enlarged BNC sample and at synthesizing cellulose nitrate (CN) therefrom. Cyclic biosynthesis of BNC was run in a semisynthetic glucose medium of 10−72 L in volume by using the Medusomyces gisevii Sa-12 symbiont. The most representative BNC sample weighing 6800 g and having an α-cellulose content of 99% and a polymerization degree of 4000 was nitrated. The nitration of freeze-dried BNC was performed with sulfuric-nitric mixed acid. BNC was examined by scanning electron microscopy (SEM) and infrared spectroscopy (IR), and CN was explored to a fuller extent by SEM, IR, thermogravimetric analysis/differential scanning analysis (TGA/DTA) and 13C nuclear magnetic resonance (NMR) spectroscopy. The three-cycle biosynthesis of BNC with an increasing volume of the nutrient medium from 10 to 72 L was successfully scaled up in nonsterile conditions to afford 9432 g of BNC gel-films. CNs with a nitrogen content of 10.96% and a viscosity of 916 cP were synthesized. It was found by the SEM technique that the CN preserved the 3D reticulate structure of initial BNC fibers a marginal thickening of the nanofibers themselves. Different analytical techniques reliably proved the resultant nitration product to be CN. When dissolved in acetone, the CN was found to form a clear high-viscosity organogel whose further studies will broaden application fields of the modified BNC.

scholarly journals A Low-Viscosity BisGMA Derivative for Resin Composites: Synthesis, Characterization, and Evaluation of Its Rheological Properties

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 338
Author(s):  
Ali Alrahlah ◽  
Abdel-Basit Al-Odayni ◽  
Haifa Fahad Al-Mutairi ◽  
Bashaer Mousa Almousa ◽  
Faisal S. Alsubaie ◽  
...  
Keyword(s):  
Substantial Reduction ◽  
Triethylene Glycol ◽  
High Viscosity ◽  
Resin Matrix ◽  
Resonance Spectroscopy ◽  
Dental Resin ◽  
Triethylene Glycol Dimethacrylate ◽  
Oh Groups ◽  
Low Viscosity ◽  
13C Nuclear Magnetic Resonance

This study aimed to synthesize new bisphenol A-glycidyl methacrylate (BisGMA) derivatives, targeting a reduction in its viscosity by substituting one of its OH groups, the leading cause of its high viscosity, with a chlorine atom. Hence, this monochloro-BisGMA (mCl-BisGMA) monomer was synthesized by Appel reaction procedure, and its structure was confirmed using Fourier transform infrared spectroscopy, 1H and 13C-nuclear magnetic resonance spectroscopy, and mass spectroscopy. The viscosity of mCl-BisGMA (8.3 Pa·s) was measured under rheometry conditions, and it was found to be more than 65-fold lower than that of BisGMA (566.1 Pa·s) at 25 °C. For the assessment of the viscosity changes of model resins in the presence of mCl-BisGMA, a series of resin matrices, in which, besides BisGMA, 50 wt % was triethylene glycol dimethacrylate, were prepared and evaluated at 20, 25, and 35 °C. Thus, BisGMA was incrementally replaced by 25% mCl-BisGMA to obtain TBC0, TBC25, TBC50, TBC75, and TBC100 blends. The viscosity decreased with temperature, and the mCl-BisGMA content in the resin mixture increased. The substantial reduction in the viscosity value of mCl-BisGMA compared with that of BisGMA may imply its potential use as a dental resin matrix, either alone or in combination with traditional monomers. However, the various properties of mCl-BisGMA-containing matrices should be evaluated.

scholarly journals Liquid-State Dewetting of Pulsed-Laser-Heated Nanoscale Metal Films and Other Geometries

2020 ◽  
Vol 52 (1) ◽  
pp. 235-262 ◽  
Author(s):  
Lou Kondic ◽  
Alejandro G. González ◽  
Javier A. Diez ◽  
Jason D. Fowlkes ◽  
Philip Rack
Keyword(s):  
Materials Science ◽  
Research Area ◽  
Metal Films ◽  
Contact Angles ◽  
Thin Metal Film ◽  
Thermal Physics ◽  
Science Community ◽  
Physical Effects ◽  
Laser Heated ◽  
Bimetallic Films

Metal films of nanoscale thickness, deposited on substrates and exposed to laser heating, provide systems that involve several interesting multiphysics effects. In addition to fluid mechanical aspects associated with a free boundary setup, other relevant physical effects include phase change, thermal flow, and liquid–solid interactions. Such films are challenging to model, in particular because inertial effects may be relevant, and large contact angles require care when considering the long-wave formulation. Applications of nanoscale metal films are numerous, and the materials science community is actively pursuing more complex setups involving templated films and substrates, bimetallic films and alloys, and a variety of elemental film geometries. The goal of this review is to discuss our current understanding of thin metal film systems, while also providing an overview of the challenges in this research area, which stands at the intersection of fluid mechanics, materials science, and thermal physics.

A brief overview of Materials Science in Uruguay

MRS Advances ◽  
2018 ◽  
Vol 3 (61) ◽  
pp. 3535-3541
Author(s):  
Ivana Aguiar ◽  
Livia Arizaga ◽  
Santiago Botasini ◽  
María Andrea De León ◽  
Sofia Favre ◽  
...  
Keyword(s):  
Materials Science ◽  
Research Area ◽  
Steady State Regime ◽  
Area Of Interest ◽  
Starting Point ◽  
State Regime ◽  
Scopus Database ◽  
Number Of Publications ◽  
Funding Opportunities

ABSTRACTMaterials science is a growing research area in Uruguay. In order to obtain a brief overview of the research done we collected information about research in this field. As a starting point, we searched in the Scopus database for the keywords: affiliation country: “Uruguay” and subject: “Materials Science” (using the “Timbó” platform). We inspected the records and we analyzed them to construct a timeline. The data show that we are in a steady state regime of number of publications that we expect to increase together with the number of students in the area, with the generation of long term policies (grants, funding opportunities), and, if we get involved in a community that promotes this area of interest.

scholarly journals Polychromy on the Antonine Wall Distance Sculptures: Non-destructive Identification of Pigments on Roman Reliefs

Britannia ◽  
2020 ◽  
Vol 51 ◽  
pp. 175-201
Author(s):  
Louisa Campbell
Keyword(s):  
Material Culture ◽  
Materials Science ◽  
Analytical Techniques ◽  
Composition Analysis ◽  
Raman Spectrometry ◽  
X Ray ◽  
Wall Distance ◽  
Depositional Processes ◽  
Non Destructive

ABSTRACTNon-destructive analytical techniques are now widely and successfully employed in the fields of materials science and conservation. Portable X-ray fluorescence (pXRF) and portable Raman spectrometry have proven particularly valuable for the rapid in-situ analysis of samples, but their applicability for the analysis of archaeological artefacts for which survival of surface treatments can be negatively impacted by post-depositional processes has been underexplored. Roman relief-sculpted monumental inscriptions from the Antonine Wall, commonly referred to as ‘Distance Slabs’, have offered an excellent opportunity to deploy these non-destructive techniques to determine whether they were originally adorned with pigments and, if so, to identify the colours used. This is a revolutionary approach to identifying colours on ancient sandstone sculpture that transforms our understanding of these unique monuments. Elemental composition analysis by pXRF has confirmed evidence for pigments and this is supported by the Raman results, making it possible to develop and reconstruct a palette of colours that originally brought these monuments to life in vibrant polychrome. The research offers a new methodology for identifying pigments on sandstone sculpture and opens new avenues for investigating other classes of material culture alongside the development of bespoke analytical equipment.

Responsive materials

MRS Bulletin ◽  
2010 ◽  
Vol 35 (9) ◽  
pp. 659-664
Author(s):  
Cameron Alexander ◽  
Iqbal Gill
Keyword(s):  
Materials Science ◽  
Ionization State ◽  
Responsive Materials ◽  
Functional Behavior ◽  
Smart Surfaces ◽  
Simple Change ◽  
The Common ◽  
The Many ◽  
Application Fields ◽  
Insight Into

Responsive materials cover a breadth of types and many application fields. The common feature in all cases is a nonlinear change in properties or behavior as a result of a stimulus. The material response can range from a simple change in conformation or ionization state, through to phase transitions, bulk aggregation, or complete dissolution. As a consequence, sensing and actuation are the most investigated functions of these materials. In this issue, we have chosen to focus on responsive materials as exemplified by externally switchable, environmentally activated, and reversibly or controllably triggered systems. The chemistries of these materials, their physical properties, functional behavior, and activity are all linked, so we have aimed to cover the many disciplines underlying responsive materials through articles featuring areas that already span disparate research topics. These areas include drug delivery, smart surfaces, and nanotube transducers. The responsive materials field is growing in excitement as well as activity, and we hope that readers will gain an insight into this fascinating branch of materials science through this MRS Bulletin issue.

Combining XRD and XRF analysis in one Rietveld-like fitting

2017 ◽  
Vol 32 (S1) ◽  
pp. S225-S230 ◽  
Author(s):  
M. Bortolotti ◽  
L. Lutterotti ◽  
G. Pepponi
Keyword(s):  
Data Acquisition ◽  
Elemental Composition ◽  
Analytical Techniques ◽  
Sample Volume ◽  
Combined Approach ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Methodology ◽  
Simple Matrix ◽  
Application Fields

X-ray diffraction (XRD) and X-ray fluorescence (XRF) are widely used analytical techniques for materials characterization; the information they provide can be considered complementary, as the former is mostly used to obtain crystallographic information and analyze phase content, whereas the latter is sensitive to elemental composition. Many researchers and technologists working in a variety of application fields already use them together in some sort of a “combined” approach, by separately performing XRD and XRF data collection and analysis on the same sample and then comparing the analytical results obtained to integrate and complement the respective analytical information. In this work, we propose a true combined approach to merge both XRD and XRF data acquisition and analysis. Custom analytical X-ray instrumentation has been developed to perform the simultaneous data acquisition, by using a single X-ray source and dedicated detectors to collect the diffracted and fluorescent X-ray photons from the same sample volume. Additionally, a combined XRD/XRF data analysis methodology has been implemented by extending Rietveld based code to incorporate the full pattern fitting of XRF spectra starting from the phases instead of a simple matrix elemental composition. We report two analytical examples from different application fields to better illustrate the capabilities of the proposed approach.

Sustainable sources need reliable standards

2017 ◽  
Vol 202 ◽  
pp. 281-301 ◽  
Author(s):  
Maxim V. Galkin ◽  
Davide Di Francesco ◽  
Ulrica Edlund ◽  
Joseph S. M. Samec
Keyword(s):  
Lignocellulosic Biomass ◽  
Cellulose Fiber ◽  
Analytical Techniques ◽  
Research Area ◽  
Research Field ◽  
Raw Material ◽  
Pulp Industry ◽  
Paper And Pulp ◽  
Paper And Pulp Industry ◽  
Analytical Tools

This review discusses the challenges within the research area of modern biomass fractionation and valorization. The current pulping industry focuses on pulp production and the resulting cellulose fiber. Hemicellulose and lignin are handled as low value streams for process heat and the regeneration of process chemicals. The paper and pulp industry have therefore developed analytical techniques to evaluate the cellulose fiber, while the other fractions are given a low priority. In a strive to also use the hemicellulose and lignin fractions of lignocellulosic biomass, moving towards a biorefining concept, there are severe shortcomings with the current pulping techniques and also in the analysis of the biomass. Lately, new fractionation techniques have emerged which valorize a larger extent of the lignocellulosic biomass. This progress has disclosed the shortcomings in the analysis of mainly the hemicellulose and lignin structure and properties. To move the research field forward, analytical tools for both the raw material, targeting all the wood components, and the generated fractions, as well as standardized methods for evaluating and reporting yields are desired. At the end of this review, a discourse on how such standardizations can be implemented is given.

scholarly journals Development of Indonesia Scientific Publications of Physical Education in Reputable International Journals: A Bibliometric Analysis

2021 ◽  
Vol 6 (1) ◽  
pp. 59-67
Author(s):  
Yulingga Nanda Hanief ◽  
Deddy Whinata Kardiyanto ◽  
Mashuri Eko Winarno ◽  
Aridhotul Haqiyah
Keyword(s):  
Physical Education ◽  
Bibliometric Analysis ◽  
Materials Science ◽  
Theory Development ◽  
Educational Practice ◽  
Analysis Data ◽  
Research Process ◽  
Research Area ◽  
Scientific Publications ◽  
Prolific Author

This study aimed to determine trends in scientific publications and map the scope of thematic research in the field of Physical Education, especially for articles published in reputable international journals (Scopus) writen by Indonesian authors. The research process was focused on the following questions: (1) how is the productivity of Physical Education publications developing in Indonesia?; (2) who are the main contributors (author, University, and name of publication) for the published publications?; (3) what are the thematic areas that attract the most attention of academics?; and (4) what topics are emerging in the field of publication?. It’s used the Scopus database as the source of bibliometric analysis data for the research sampling process. The samples were 55 articles found through keyword "physical education" in the "article title" published in international journals indexed by Scopus. This study applied keyword co-occurrence analysis to identify and explore the main thematic areas and topics that appeared in publications. The VOSviewer software was used to support the analysis process and visualize findings. The results of the study show that physical education is a research area that still needs to be developed, referring to the productivity of publications from 2013 to 2020, which the range of publication was still below 15 per year. The collected research results were scattered in the fields of engineering studies (21), social sciences (18), and materials science (14). The main contributor of the publication was Indonesian University of Education (24). The most prolific author was Tedi Supriyadi from the Indonesian University of Education. In the Physical Education publications, six major thematic groups were identified, namely: (1) physical activity of school pupils; (2) sports; (3) Physical Education; (4) health; (5) education; and (6) creativity. This study conveyed to public that the mapping using bibliometric analysis contributes to a better understanding of the development patterns of publications in the field of Physical Education. By finding thematic areas and topics appearing in publications, this study conveys information of important issues for further research and theory development as well as for educational practice or application.

Brain Homogenate Standards for Analysis of Aluminum in Alzheimer’s Disease

1996 ◽  
Vol 54 ◽  
pp. 750-751
Author(s):  
C. R. Swyt ◽  
Q.R. Smith ◽  
Q.S. Deng
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Analytical Techniques ◽  
Brain Homogenate ◽  
X Ray ◽  
Freeze Dried ◽  
Backscattered Electron ◽  
Standard Set ◽  
The Many ◽  
Electron Imaging

Aluminum doped brain homogenates have been proposed as a common set of standards to help resolve the disparity among the reported measured concentrations in plaques and tangled neurons in postmortem Alzheimer’s Disease brain specimens. Among the many analytical techniques utilized electron probe microanalysis (EPMA) alone provides both the capability to identify, by backscattered electron imaging, cells in unstained sections and to achieve, using wavelength dispersive x-ray spectrometry (WDS), a sensitivity for aluminum approaching the higher reported normal aged brain concentrations. We have prepared a set of freeze-dried 30 μm cryosections of aluminum doped homogenized rat brain. We report here the preliminary results of analysis by EPMA and briefly discuss some of the practical considerations in using such homogenates as a standard set for quantitation by WDS.

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