960 resultados para Wood - Drying
Resumo:
coating composition comprising an oxidatively drying coating binder and a chelate comprising at least one group according to the following formula (I): forming a complex with a metal ion, A1 and A2 both being an aromatic residue, R1 and R3 being covalently bonded groups, and R2 being a divalent organic radical, wherein at least one solubilizing group is coivalently bonded to the chelating compound. The solubilizing group is a non-polar group, preferable an aliphatic group having at least four carbon atoms, covalently bonded to A1 and/or A2. The metal ion is a divalent ion of a metal selected from the group of manganese, cobalt, copper, lead, zirconium, iron, lanthanium, cerium, vanadium, and clacium or a trivalent ion of a metal selected from the group of manganese, cobalt, lead, zirconium, iron, lanthanium, cerium, and vanadium, combined with a monovalent counterion.
Resumo:
The antioxidant capacity of oak wood used in the ageing of wine was studied by four different methods: measurement of scavenging capacity against a given radical (ABTS, DPPH), oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP). Although, the four methods tested gave comparable results for the antioxidant capacity measured in oak wood extracts, the ORAC method gave results with some differences from the other methods. Non-toasted oak wood samples displayed more antioxidant power than toasted ones due to differences in the polyphenol compositon. A correlation analysis revealed that ellagitannins were the compounds mainly responsible for the antioxidant capacity of oak wood. Some phenolic acids, mainly gallic acid, also showed a significant correlation with antioxidant capacity.
Resumo:
During spray drying, emphasis is placed on process optimisation to generate favourable particle morphological and flow properties. The effect of the initial feed solution composition on the drug release from the prepared microparticles is rarely considered. We investigated the effects of solvent composition, feed solution concentration and drug-loading on sodium salicylate, hydrocortisone and triamcinolone release from spray dried Eudragit L100 microparticles. Eudragit L100 is a pH-responsive polymer whose dissolution threshold is pH 6 so dissolution testing of the prepared microparticles at pH 5 and 1.2 illustrated non-polymer controlled burst release. Increasing the water content of the initial ethanolic feed solution significantly reduced hydrocortisone burst release at pH 5, as did reducing the feed solution concentration. These findings caution that changes in feed solution concentration or solvent composition not only affect particles’ morphological characteristics but can also negatively alter their drug release properties. This work also illustrate that drug-free microparticles can have different morphological properties to drug-loaded microparticles. Therefore, process optimisation needs to be carried out using drug-loaded systems. Depending on the physicochemical properties of the encapsulated API, drug-loading can affect the polymer solubility in the initial feed solution with consequent impact on microparticles morphological and release properties.
Resumo:
The objective of this study was to investigate the effect of drying conditions on the phenolic constituents and colour of extracts of organically grown white willow and meadowsweet for incorporation into a functional beverage with potential anti-inflammatory properties. The herbs were freeze-dried, air-dried, oven or tray-dried at 30 or 70 °C. The drying kinetics of the herbs was first determined. Both drying temperature and method had a significant effect (p ≤ 0.05) on the drying rate, the samples tray-dried had a faster drying rate than those oven-dried. Results show that for meadowsweet and willow, freeze-drying and oven or tray drying at 30 °C had no significant effect on the phenolic constituents (e.g. total phenols, salicylates, quercetin) or the colour of the extracts in comparison to traditional air-drying. Although increasing the drying temperature to 70 °C resulted in an increase in the drying rate of both herbs it also led to the loss of some phenolic compounds. Also, the extracts from both herbs dried at 70 °C were significantly (p ≤ 0.05) redder than the other drying methods. Therefore, tray drying these herbs at low temperatures may reduce drying time without having a significant effect on the phenolic content and colour of the extracts.
Resumo:
Skim milk was concentrated by reverse osmosis (RO), nanofiltration (NF) and ultrafiltration (UF) and the retentates were spray-dried. The resulting powders were reconstituted to 25% TS and sterilised to evaluate their heat stability. Reverse osmosis led to maximum retention of calcium, a fall in pH for its retentate and its reconstituted powder. All RO powders produced a weak gel on heating. Some calcium was lost during NF and a greater amount during UF. Their resulting reconstituted powders had a higher pH than those produced by RO. Powders produced by UF showed poor heat stability. Only one powder produced by NF showed good heat stability. This could be improved by addition of stabilisers at appropriate addition rates.
Resumo:
The wood mouse is a common and abundant species in agricultural landscape and is a focal species in pesticide risk assessment. Empirical studies on the ecology of the wood mouse have provided sufficient information for the species to be modelled mechanistically. An individual-based model was constructed to explicitly represent the locations and movement patterns of individual mice. This together with the schedule of pesticide application allows prediction of the risk to the population from pesticide exposure. The model included life-history traits of wood mice as well as typical landscape dynamics in agricultural farmland in the UK. The model obtains a good fit to the available population data and is fit for risk assessment purposes. It can help identify spatio-temporal situations with the largest potential risk of exposure and enables extrapolation from individual-level endpoints to population-level effects. Largest risk of exposure to pesticides was found when good crop growth in the “sink” fields coincided with high “source” population densities in the hedgerows. Keywords: Population dynamics, Pesticides, Ecological risk assessment, Habitat choice, Agent-based model, NetLogo
Resumo:
Novel oxazoline-based comb-polymers possessing linoleyl or oleic side chains have been synthesized and used to produce low viscosity coatings. Inclusion of the polymers in model paint formulations results in coatings that exhibit faster drying times than commercially available alkyd resin formulations. The comb polymers were produced from diol substituted oxazoline monomers that were synthesized through a scalable, solvent free protocol and purified by simple recrystallisation. Co-polymerisation of the oxazolines with adipic acid at 160 °C in the bulk resulted in the targeted polyester comb type polymers. The polymers were soluble in a range of organic solvents and compatible with commercial alkyd resins. Model paint formulations containing up to 40 wt% of the linoleyl-based comb polymers exhibited a dramatic reduction in viscosity (from 35 to 13 Poise at 25 °C) with increasing quantities of polymer added. Dynamic mechanical analysis (DMA) studies revealed that the drying rate of the model paint formulations containing the comb polymers was enhanced when compared with that of commercial alkyd resins.
Resumo:
Sensory perception has been found to change during ageing. The perception of mouth feel by older adults, and the role of ageing on the sensory perception of texture attributes is uncertain. . This study investigated perception of the textural attributes of thickness, mouth-coating and mouth-drying, in the context of dairy beverages, by older and younger adults. Just noticeable differences (JND) of a starch thickener and for cream concentration within milk were established for thickness and mouth-coating perception, finding no age-related differences between participant groups. Mouth-drying was assessed through the directional paired comparison of a mouth-drying milk beverage to a skimmed milk sample. The older adults were found to be more sensitive to mouth-drying (p=0.03) than the younger adults. This study found no age-related decline in texture perception with older adults finding perception of some attributes such as mouth-drying enhanced by ageing.