Search results for "Analytical"
showing 10 items of 9586 documents
Fibre fragment distribution in a single-fibre composite tension test
2001
Abstract Single fibre fragmentation tests are performed for brittle fibres with Weibull strength distribution and different surface treatments. The fragmentation process is modelled and closed-form expressions for break spacing distribution are obtained. The model accounts for the effect of finite fibre length on the initial fragmentation as well as for break interaction on the advanced fragmentation stage. It is assumed that the exclusion zone due to fibre–matrix interface failure and stress recovery in the fibre is linearly dependent on the applied load. This assumption is validated experimentally. The derived theoretical average fragment length dependence on applied load is used to deter…
Advantages of Hyaluronic Acid and Its Combination with Other Bioactive Ingredients in Cosmeceuticals
2021
This study proposes a review on hyaluronic acid (HA) known as hyaluronan or hyaluronate and its derivates and their application in cosmetic formulations. HA is a glycosaminoglycan constituted from two disaccharides (N-acetylglucosamine and D-glucuronic acid), isolated initially from the vitreous humour of the eye, and subsequently discovered in different tissues or fluids (especially in the articular cartilage and the synovial fluid). It is ubiquitous in vertebrates, including humans, and it is involved in diverse biological processes, such as cell differentiation, embryological development, inflammation, wound healing, etc. HA has many qualities that recommend it over other substances used…
PQ and Harmonic Assessment Issues on Low-Cost Smart Metering Platforms: A Case Study
2020
This paper presents a feasibility study on how to implement power quality (PQ) metrics in a low-cost smart metering platform. The study is aimed at verifying the possibility of implementing PQ monitoring in distribution networks without replacing existing smart metering devices or adding new modules for PQ measurements, thus zeroing the installation costs. To this aim, an electronic board, currently used for remote energy metering, was chosen as a case study, specifically the STCOMET platform. Starting from the specifications of this device, the possibility of implementing power quality metrics is investigated in order to verify if compliance with standard requirements for PQ instruments ca…
Multispectral filter arrays: Recent advances and practical implementation
2014
Thanks to some technical progress in interferencefilter design based on different technologies, we can finally successfully implement the concept of multispectral filter array-based sensors. This article provides the relevant state-of-the-art for multispectral imaging systems and presents the characteristics of the elements of our multispectral sensor as a case study. The spectral characteristics are based on two different spatial arrangements that distribute eight different bandpass filters in the visible and near-infrared area of the spectrum. We demonstrate that the system is viable and evaluate its performance through sensor spectral simulation. Multispectral filter arrays: Recent advan…
Assessing the quality of dissolved organic matter in forest soils using ultraviolet absorption spectrophotometry
2007
Abbreviations: DOC, dissolved organic carbon; SUVA, specifi c ultraviolet absorbance; UV, ultraviolet. Ultraviolet spectrophotometry was used to investigate the effects, 30 yr after planting, of tree species substitution on the aromatic C content and related properties of dissolved organic carbon (DOC). Precautions were taken to correct measurements for the absorbance of NO 3 and dissolved Fe. In litter leachates, a signifi cant reduction in the aromatic content of DOC was found in the Douglas-fi r [Pseudotsuga menziesii (Mirb.) Franco] plantation but not in the beech (Fagus sylvatica L.) plantation. The disturbance of short-term C dynamics thus revealed agreed well with fi eld observations…
Ti Alloyed α-Ga2O3: Route towards Wide Band Gap Engineering
2020
The suitability of Ti as a band gap modifier for &alpha
Evaluation of the Behavior of Phenolic Compounds and Steviol Glycosides of Sonicated Strawberry Juice Sweetened with Stevia (Stevia rebaudiana Berton…
2019
In this study, the influence of stevia addition and sonication processing parameters on the phenolic content and profile as well as the steviol glycosides of strawberry juice-based samples was investigated. For this purpose, three matrices&mdash
Discovery of a new class of sortase a transpeptidase inhibitors to tackle gram-positive pathogens: 2-(2-phenylhydrazinylidene)alkanoic acids and rela…
2016
A FRET-based random screening assay was used to generate hit compounds as sortase A inhibitors that allowed us to identify ethyl 3-oxo-2-(2-phenylhydrazinylidene)butanoate as an example of a new class of sortase A inhibitors. Other analogues were generated by changing the ethoxycarbonyl function for a carboxy, cyano or amide group, or introducing substituents in the phenyl ring of the ester and acid derivatives. The most active derivative found was 3-oxo-2-(2-(3,4dichlorophenyl)hydrazinylidene)butanoic acid (2b), showing an IC50 value of 50 µM. For a preliminary assessment of their antivirulence properties the new derivatives were tested for their antibiofilm activity. The most active compo…
Comparison of local electrochemical impedance measurements derived frombi-electrode and microcapillary techniques
2009
Abstract In the present paper, local electrochemical impedance spectra were obtained on a 316L stainless steel from two configurations: a dual microelectrode (bi-electrode) and microcapillaries. With the bi-electrode, the local impedance measurements were made from the ratio of the applied voltage to the local current density calculated from the application of the ohm's law. With the use of microelectrochemical cells, the specimen surface area in contact with the electrolyte is limited by the use of glass microcapillaries and the local impedance was defined from the ratio of the local potential to the local current restricted to the analysed surface area. Differences and similarities observ…
Trapped Ion Oscillation Frequencies as Sensors for Spectroscopy
2010
The oscillation frequencies of charged particles in a Penning trap can serve as sensors for spectroscopy when additional field components are introduced to the magnetic and electric fields used for confinement. The presence of so-called "magnetic bottles" and specific electric anharmonicities creates calculable energy-dependences of the oscillation frequencies in the radiofrequency domain which may be used to detect the absorption or emission of photons both in the microwave and optical frequency domains. The precise electronic measurement of these oscillation frequencies therefore represents an optical sensor for spectroscopy. We discuss possible applications for precision laser and microw…