208 research outputs found
A ‘Periodic Table’ of mass spectrometry instrumentation and acronyms
The number of acronyms in mass spectrometry (MS) and hyphenated techniques are growing rapidly. The ever-widening range of users of MS technology has led to variations in terminology and how it has been applied. The International Union of Pure and Applied Chemistry (IUPAC) has undertaken a review of MS nomenclature resulting in an extensive publication, describing over 500 terms, and is the defining resource for mass spectrometrists. However, for less experienced users of MS, this IUPAC document may require greater explanation as it is not intended to explain the basis of these terms. Given this, the Analytical Methods Committee (AMC) of the Royal Society of Chemistry highlighted an alternative text was required to help understand these terms, how and why they are used in combination, that may be accessible to non-MS experts. This manuscript describes the structure of typical MS instrumentation (sample introduction, ionisation source, mass analyser, detector, data acquisition/processing) and hyphenated technologies whereby each section is discussed and summarised in context and presented as a recognisable tabulated format
Understanding Uncertainties in Thermographic Imaging
7 p.The present article proposes a workflow based on free/open-source software solutions for the acquisition of competences in engineering courses related to the use of thermographic images. The approach is aimed to three-dimensional visualization techniques over thermographic images to improve the comprehension and interpretation of the different error sources that affects the measurements, and therefore the conclusions and analysis derived from them. The present work is framed inside the virtual laboratories discipline, as the new learning material can be employed for the acquisition of competences and skills. Additionally, it can be used for the evaluation of competences in asynchronous and e-learning programs. The learning materials could be easily deployed in a learning management system, allowing the students to work with the models by means of open-source solutions easily, both in asynchronous and face-to-face courses. Consequently, the present approach will improve the application of professional techniques, so the future professionals will reach the working market better prepared.S
Using lignocellulosic fractions of coffee husk to improve properties of compatibilised starch-PLA blend films
[EN] The effectiveness of the incorporation of cellulosic reinforcing agents (cellulosic fibres: CF and cellulose nanocrystals: CNC) and antioxidant aqueous extract (AE) from coffee husk at improving the functional properties of compatibilised starch-PLA blend films was studied. Tensile and barrier properties, crystallization pattern and thermal behaviour were analysed in films containing 1 wt% of CF or CNC incorporated by two different methods or 5.8 wt% of antioxidant extract. The antioxidant properties of the films were also tested through their efficacy at preserving sunflower oil from oxidation. Of the cellulosic fractions, CNC directly blended with the starch phase were the most effective at reinforcing tensile properties of the material (148% and 45% increase in elastic modulus and tensile strength, respectively) and at reducing their water vapour and oxygen permeability (28% and 42% reduction, respectively). The AE did not improve the mechanical performance of the blend films, but conferred antioxidant capacity useful for food packaging applications.The authors thank the Ministerio de Economia y Competitividad (Spain) for the financial support provided through Project AGL2016-76699-R. The authors also wish to thank the Electron Microscopy Service of the UPV for their technical assistance.Collazo-Bigliardi, S.; Ortega-Toro, R.; Chiralt Boix, MA. (2019). Using lignocellulosic fractions of coffee husk to improve properties of compatibilised starch-PLA blend films. Food Packaging and Shelf Life. 22:1-10. https://doi.org/10.1016/j.fpsl.2019.100423S1102
Development and Validation of an Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES) Method for Trace Element Determination in Vinegar
Effect of sodium replacement in cookies on the formation of process contaminants and lipid oxidation
A template-free and low temperature method for the synthesis of mesoporous magnesium phosphate with uniform pore structure and high surface area
Mesoporous phosphates are a group of nanostructured materials with promising applications, particularly in biomedicine and catalysis. However, their controlled synthesis via conventional template-based routes presents a number of challenges and limitations. Here, we show how to synthesize a mesoporous magnesium phosphate with a high surface area and a well-defined pore structure through thermal decomposition of a crystalline struvite (MgNH4PO4·6H2O) precursor. In a first step, struvite crystals with various morphologies and sizes, ranging from a few micrometers to several millimeters, had been synthesized from supersaturated aqueous solutions (saturation index (SI) between 0.5 and 4) at ambient pressure and temperature conditions. Afterwards, the crystals were thermally treated at 70-250 °C leading to the release of structurally bound water (H2O) and ammonia (NH3). By combining thermogravimetric analyses (TGA), scanning and transmission electron microscopy (SEM, TEM), N2 sorption analyses and small- and wide-angle X-ray scattering (SAXS/WAXS) we show that this decomposition process results in a pseudomorphic transformation of the original struvite into an amorphous Mg-phosphate. Of particular importance is the fact that the final material is characterized by a very uniform mesoporous structure with 2-5 nm wide pore channels, a large specific surface area of up to 300 m2 g-1 and a total pore volume of up to 0.28 cm3 g-1. Our struvite decomposition method is well controllable and reproducible and can be easily extended to the synthesis of other mesoporous phosphates. In addition, the so produced mesoporous material is a prime candidate for use in biomedical applications considering that magnesium phosphate is a widely used, non-toxic substance that has already shown excellent biocompatibility and biodegradability
Separation and recovery of critical metal ions using ionic liquids
Separation and purification of critical metal ions such as rare-earth elements (REEs), scandium and niobium from their minerals is difficult and often determines if extraction is economically and environmentally feasible. Solvent extraction is a commonly used metal-ion separation process, usually favored because of its simplicity, speed and wide scope, which is why it is often employed for separating trace metals from their minerals. However, the types of solvents widely used for the recovery of metal ions have adverse environmental impact. Alternatives to solvent extraction have been explored and advances in separation technologies have seen commercial establishment of liquid membranes as an alternative to conventional solvent extraction for the recovery of metals and other valuable materials. Liquid membrane transport incorporates solvent extraction and membrane separation in one continuously operating system. Both methods conventionally use solvents that are harmful to the environment, however, the introduction of ionic liquids (ILs) over the last decade is set to minimize the environmental impact of both solvent extraction and liquid membrane separation processes. ILs are a family of organic molten salts with low or negligible vapour pressure which may be formed below 100 oC. Such liquids are also highly thermally stable and less toxic. Their ionic structure makes them thermodynamically favorable solvents for the extraction of metallic ions. The main aim of this article is to review the current achievements in the separation of REE, scandium, niobium and vanadium from their minerals, using ILs in either solvent extraction or liquid membrane processes. The mechanism of separation using ILs is discussed and the engineering constraints to their application are identified
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