Search results for "Gradation"
showing 10 items of 1275 documents
ARCHITECTURAL SURVEY TECHNIQUES FOR DEGRADATION DIAGNOSTICS. AN APPLICATION FOR THE CULTURAL HERITAGE
2021
Abstract. The great technological development in recent years in the field of architectural survey has made possible increasingly expeditious and less invasive investigations with the aim of acquiring a series of data related to the asset and fundamental for the protection of cultural heritage. In addition, the synergy between the various techniques represents an added value able, not only, to fill possible gaps and lacks arising from application limits of the instruments, but also to enhance the peculiarities of the same. This paper presents an integrated survey activity (range-based, image-based and IR thermography techniques) aimed at applying the combination and collaboration of multipl…
Protective effect of paraoxonase-2 against endoplasmic reticulum stress-induced apoptosis is lost upon disturbance of calcium homoeostasis
2008
PON2 (paraoxonase-2) is a ubiquitously expressed antioxidative protein which is largely found in the ER (endoplasmic reticulum). Addressing the cytoprotective functions of PON2, we observed that PON2 overexpression provided significant resistance to ER-stress-induced caspase 3 activation when the ER stress was induced by interference with protein modification (by tunicamycin or dithiothreitol), but not when ER stress was induced by disturbance of Ca2+ homoeostasis (by thapsigargin or A23187). When analysing the underlying molecular events, we found an activation of the PON2 promoter in response to all tested ER-stress-inducing stimuli. However, only tunicamycin and dithiothreitol resulted i…
Effect of the applied organic load rate on biodegradable polymer production by mixed microbial cultures in a Sequencing Batch Reactor
2006
This article studies the operation of a new process for the production of biopolymers (polyhydroxyalkanoates, PHAs) at different applied organic load rates (OLRs). The process is based on the aerobic enrichment of activated sludge to obtain mixed cultures able to store PHAs at high rates and yields. A mixture of acetic, lactic, and propionic acids at different concentrations (in the range 8.5-31.25 gCOD/L) was fed every 2 h in a sequencing batch reactor (SBR). The resulting applied OLR was in the range 8.5-31.25 gCOD/L/day. Even though, as expected, the increase in the OLR caused an increase in biomass concentration (up to about 8.7 g COD/L), it also caused a relevant decrease of maximal po…
Gradation of Fuzzy Preconcept Lattices
2021
Noticing certain limitations of concept lattices in the fuzzy context, especially in view of their practical applications, in this paper, we propose a more general approach based on what we call graded fuzzy preconcept lattices. We believe that this approach is more adequate for dealing with fuzzy information then the one based on fuzzy concept lattices. We consider two possible gradation methods of fuzzy preconcept lattice—an inner one, called D-gradation and an outer one, called M-gradation, study their properties, and illustrate by a series of examples, in particular, of practical nature.
A comparative thermogravimetric study of waterlogged archaeological and sound woods
2010
Waterlogged archaeological woods Pinus pinaster and Fagus sylvatica L. were analyzed by using TG technique. Degradation processes ascribable to the holocellulose decay were evidenced at nearly the same temperature for sound and archaeological samples. The residual matters at 600 and 900 °C of the sound woods are much lower than those of archaeological waterlogged woods in agreement with the presence of inorganic materials encapsulated during the burial into the marine environment. It was proposed a new protocol to rapidly calculate the maximum water content parameter, which is related to the wood degradation state. TG experiments at variable heating rates were performed to obtain kinetic pa…
Investigation of thermal stability of ethylene copolymers with POSS - Study under static and dynamic conditions
2018
Abstract In the paper there was studied thermal stability of a series of ethylene copolymers with monoalkenylsiloxy- or monoalkenylsilsesquioxanes (POSS) under dynamic and static conditions. The copolymers proved to be more thermally stable than neat polyethylene and neat silsesquioxane comonomers. The kind and the content of the POSS units significantly affected degradation of the copolymers. Thermal oxidation process resulted in structural changes of the (co)polymers as it was evidenced by the variations in the kind and content of carbonyl, as well as by unsaturated end groups. Depending on the structure of the POSS comonomer incorporated into the polymer chain, the silsesquioxane units o…
Evaluation of wood-polyethylene composites biodegradability caused by filamentous fungi
2017
Abstract This study describes the impact of filamentous fungi on wood-polymer composites (WPCs) containing various types of fillers (coniferous, deciduous, cellulose) in the amount of 30 wt.% to 50 wt.%. The selection of fungal strain of filamentous fungi was performed prior to the study on the impact of the wood type on the progress of WPCs biodegradability. The changes associated with various water absorption of the examined WPCs, were observed using scanning electron microscopy (SEM). The impact of fungal mycelium, which had affected the changes in WPCs material, was examined using thermogravimetric analysis (TG). The results showed, that the growth of mycelium on WPCs, influenced mainly…
PMMA-titania nanocomposites: Properties and thermal degradation behavior
2012
Titania nanoparticles were prepared using a solegel method and calcination at 200 and 600 � C in order to obtain anatase and rutile phases, respectively. The obtained powders were used to prepare PMMAe titania nanocomposites by a melt compounding method. The effect of the crystalline phase and the amount of titania, in the range 1e5 wt.%, on the morphology, mechanical properties and thermal degradation kinetics of PMMA was investigated by means of X-ray diffractometry (XRD), transmission electron microscopy (TEM), 13 C cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy ( 13 C{ 1 H}CP-MAS NMR), including the measurement of proton spinelattice relaxation time in t…
Tungstophosphoric acid supported on polycrystalline TiO2 for the photodegradation of 4-nitrophenol in aqueous solution and propan-2-ol in vapour phase
2009
Abstract The present work reports the preparation of samples based on Millennium PC-500 TiO 2 loaded with different amounts of tungstophosphoric acid (up to 30% in weight) and their characterisation by means of different physicochemical techniques: powder X-ray diffraction, N 2 adsorption–desorption at −196 °C, transmission electron microscopy, UV–vis and FT-IR spectroscopies and thermogravimetric analyses. The acidity of samples was evaluated by FT-IR using pyridine as probe molecule, and the catalysts activity was tested for the photodegradation of 4-nitrophenol in aqueous solution and for the photo-oxidation of propan-2-ol in vapour phase. The results show a noticeable improvement (8 and…
Influence of crystallinity and OH surface density on the photocatalytic activity of TiO2 powders
2014
Abstract The aim of the work was to study the influence of crystallinity and OH surface density on the photocatalytic activity of two commercial and two home-prepared TiO 2 powders. The samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG) and electron paramagnetic resonance (EPR) measurements. The photoactivity of the powders was tested employing the photodegradation of 4-nitrophenol (4-NP) and the selective oxidation of 4-methoxybenzyl alcohol (4-MBA) to 4-methoxybenzaldehyde ( p -anisaldehyde) under UV irradiation. An anti-correlation between oxidant power and selectivity of the various samples was found. A higher rate of 4-NP degradation was exhibited by…