Search results for "EFA"
showing 10 items of 1142 documents
Hydrothermal liquefaction of wood using a modified multistage shrinking-core model
2020
Abstract Wood liquefaction in hot compressed water is modeled using the hydrolysis of Cellulose, Hemicellulose, and Lignin. These three components are reacted under catalyst-free subcritical conditions in a temperature range from 553 K to 640 K, and the heating rate ranges from 2 K/min to 6 K/min. Using a simplified reaction scheme, water-soluble products 1 (WSP), Biocrude, char, and gas are generated through intermediates with each wood component. A modified multistage shrinking core model is employed to simulate biomass particle degradation. The reaction and kinetic regime of the hydrothermal liquefaction 2 (HTL) process are treated separately for each wood component. Although the lack of…
Thermal Decomposition and Combustion of Microwave Pre-Treated Biomass Pellets
2021
The objective of the study was to investigate a more effective use of commercially available biomass pellets (wheat straw, wood, peat) using microwave pretreatment to improve heat production. Pellets were pretreated using the originally designed microwave torrefaction device. The effects of microwave (mw) pretreatment were quantified, providing measurements of the weight loss and elemental composition of pellets and estimating the effect of mw pretreatment on their porosity, surface area and calorific values at pretreatment temperatures of T = 448–553 K. Obtained results show that the highest structural variations and elemental composition during mw pretreatment were obtained for wheat stra…
Sorption properties of torrefied wood and charcoal
2014
AbstractPre-treating biomass by torrefaction is assumed to improve the material's storage properties because of reducing hydrophilicity. In order to assess the effect of sorption on storage properties, the adsorption of water vapour and capillary absorption of liquid water in torrefied and charred spruce and birch were studied. In addition, the chemical changes were evaluated through Fourier Transform Infrared (FT-IR) spectroscopy. Adsorption decreased notably as severity of treatment increased, as was expected due to degradation of the wood constituents, namely hemicelluloses and amorphous cellulose. Capillary absorption increased with increasing severity in spruce samples while birch show…
Numerical modeling and validation of hydrothermal liquefaction of a lignin particle for biocrude production
2021
Abstract Lignin liquefaction process under catalyst-free conditions in a temperature range from 573 K to 647 K is investigated with this mathematical model. Based on the theoretical understanding of the physical and chemical processes of the liquefaction process in subcritical temperatures, a comprehensive mathematical model for the decomposition of lignin by hydrolysis reaction pathway is developed on the results of a series of batch experiments. The model consists of four main sections. They are liquefaction of lignin particle, oily film, and inorganic (ash) layer formation behavior during the liquefaction, kinetic model to model further liquefaction process of initial products, and the l…
Considerations on factors affecting biochar densification behavior based on a multiparameter model
2021
The optimization of upscaled biochar pelleting is limited by lack of knowledge regarding the effects of process parameters. A multiparameter model, coupled to a single pellet press unit, was for the first time applied to biochar production to predict the upscaled biochar pelleting process behavior. The model permits to estimate in a time and cost-effective way how the die friction forces, quantified through the pellet exiting pressure, are affected by the key process parameters. It was observed that to achieve acceptably low exiting pressures (in the order of 100 MPa), it was critical to produce biochar at high temperatures (e.g. 600 °C). Addition of water as a binder is also beneficial, wh…
Petri Net Modelling of the Starch Enzymatic Liquefaction
2012
This paper investigates the use of the Petri Net modelling language for the description and analysis of the enzymatic reactions that are used for the starch liquefaction. The Coloured Petri Net formalism supported by the CPN Tools modelling and simulation environment is used. The pools of substrates and products are represented as the places and the possible reactions as the transition of the net. The concurrent reactions are modelled trough transitions that are enabled at the same time. The occurrence probabilities associated with each of these concurrent transitions are chosen as the model parameters. The analysis of the specific properties of the model is used to fit the model to data fr…
Default Mode Network Efficiency Is Correlated With Deficits in Inhibition in Adolescents With Inhalant Use Disorder
2020
It is well established that alterations in cognitive function and damage to brain structures are often found in adolescents who have substance use disorder (SUD). However, deficits in executive cognitive functioning in adolescents related to the vulnerability and consumption of such substances are not well known. In this study, we use graph theoretic analysis to compare the network efficiency in the resting state for three networks---default mode network (DMN), salience network (SN) and fronto-parietal network (FPN)---between inhalant-consuming adolescents and a control group (12 to 17 years old). We analysed whether the efficiency of these functional networks was related to working memory,…
Everyday uses of standardized test information in a geriatric setting : a qualitative study exploring occupational therapist and physiotherapist test…
2014
Published version of an article in the journal: BMC Health Services Research. Also available from the publisher at: http://dx.doi.org/10.1186/1472-6963-14-72 Open Access Background: Health professionals are required to collect data from standardized tests when assessing older patients' functional ability. Such data provide quantifiable documentation on health outcomes. Little is known, however, about how physiotherapists and occupational therapists who administer standardized tests use test information in their daily clinical work. This article aims to investigate how test administrators in a geriatric setting justify the everyday use of standardized test information. Methods. Qualitative s…
How to enhance digital support for cross-organisational health care teams? A user-based explorative study
2020
Health care service provision of individualised treatment to an ageing population prone to chronic conditions and multimorbidities is threatened. There is a need for digitally supported care, that is, (1) person-centred, (2) integrated, and (3) proactive. The research project 3P, Patients and Professionals in Productive Teams, aimed to validate and verify the prerequisites for health care systems run with patient-centred service models. This paper presents an explorative study of the digital support of a cross-organisational health care team in Norway, providing services to elderly frail people with multimorbidities in hospital discharge transition. Qualitative research methods were employe…
I traffici illeciti nel Mediterraneo. Persone, stupefacenti, tabacco
2019
Attraverso la combinazione di ricerca criminologica e giuridico-normativa, e grazie anche alla collaborazione con esperti esterni (studiosi, magistrati, rappresentanti di istituzioni italiane e straniere), la ricerca da cui scaturisce il volume ha indagato le interazioni tra i diversi traffici illeciti e la criminalità organizzata nel bacino del Mediterraneo. In tale area, storicamente cruciale per la mobilità di persone e di beni, l’attenzione si è rivolta in particolare ai fenomeni del traffico e della tratta di persone, del traffico di stupefacenti e del contrabbando di sigarette. I contributi raccolti – unitamente al rapporto criminologico e ai cinque rapporti nazionali accessibili su w…