Symbolic Computation of Variational Symmetries in Optimal Control

We use a computer algebra system to compute, in an efficient way, optimal control variational symmetries up to a gauge term. The symmetries are then used to obtain families of Noether's first integrals, possibly in the presence of nonconservative external forces. As an application, we obtain eight independent first integrals for the sub-Riemannian nilpotent problem (2,3,5,8).Comment: Presented at the 4th Junior European Meeting on "Control and Optimization", Bialystok Technical University, Bialystok, Poland, 11-14 September 2005. Accepted (24-Feb-2006) to Control & Cybernetic

Green technologies in the valorization of agrofood wastes in the frame of the biorefinery concept

Food production results in the generation of residues at different step of the production chain. A great part of the residues is generated at the agricultural part of the process. Although some of these residues may have already an application as for example feed or bedding, however more energetically and economically efficient use is desirable. Especially that this kind of residues are low-cost bulky feedstock and renewable carbon source, which can be processed and valorised to produce fine chemicals and bio-based commodities fulfilling the requirement of biorefinery concept. However, considering the globally occurring changes, the valorisation of residues made in the frame of biorefinery concept must be done in the green fashion. This way the broadly understood sustainability and bio-based economy requirements can be satisfy. This work will show some examples of valorisation of food production chain residues using greener methods. The aim of this work is to demonstrate the diverse application methods of ionic liquids and high density fluids in direct integrated valorisation of biomass towards value-added chemicals

Carbon dioxide in biomass processing: contributions to the green biorefinery concept

The 21st century is witnessing a huge demand of fossil reserves coupled with a rapid reduction in readily and economically reachable oil feedstocks.The present energy demand is not fulfilled from fossil fuel sources, making the world exposed to geopolitical risk. Furthermore, concerns regarding the security of the supply chain and the environmental impacts have resulted in an ever-increasing shift of global energy policies to seek alternative technologies and sustainable sources of energy, materials, chemicals, and value-added products. Recently, the need for development of an economy based on renewable resources has been recognized by society, and diverse R&D activities have started to be funded to accomplish this aim. However, generation of bioproducts based on sustainable supply chains poses vast challenges for an eco-based economy.The simplest way to provide a supportable supply chain is through the employment of renewable biomass feedstocks, which is the only sustainable option to substitute for fossil fuel resources, as sources of organic compounds over a relatively short time scale and with limitless supply

Editorial: green and sustainable solutions for fractionating lignocellulosic biomass

No abstract available.publishe

Biorefinery approach for lignocellulosic biomass valorisation with an acidic ionic liquid

ABSTRACT: The commercialisation of the biorefinery approach involving the integration of the multi-step valorisation of low value biomass feedstock into a variety of chemicals, fuels and bioproducts is still very limited. In this context, the present work proposes an advanced methodology that comprises a cascaded approach towards wheat straw valorisation. The studied concept lies in the employment of an aqueous solution of the acidic 1-ethyl-3-methylimidazolium hydrogen sulfate ionic liquid in a selective and efficient hydrolysis of the hemicellulose fraction of wheat straw into pentoses, namely xylose and arabinose. An experimental design was utilised to search for the optimisation parameters, resulting in a maximum 80.5 wt% pentose yield in the liquor. Furthermore, the remaining solid, which contained practically all of the initial cellulose and lignin, was processed by considering two scenarios: (i) a direct enzymatic hydrolysis of the reaction solid, which yielded 75.8 mol% glucose; or (ii) a preceding extraction of lignin followed by enzymatic saccharification of the cellulose pulp, which yielded 91.3 mol% glucose. For both scenarios, lignin-rich solid fractions were obtained with distinct purities and yields. Additionally, the second scenario allowed producing a stream of value-added aromatic (phenolic) compounds. This work also overcame the challenges in IL recycling and reuse, with a simultaneous recovery of the pentoses from the reaction liquor as high as 88.6 mol%.info:eu-repo/semantics/publishedVersio

Patients and family caregivers’ perceptions on two stress reduction interventions with patients with chronic diabetic foot ulcers: a qualitative study

M.Graça Pereira, Susana Pedras, André Louro et al. Patients and Family Caregivers’ Perceptions on Two Stress Reduction Interventions with Patients with Chronic Diabetic Foot Ulcers: A Qualitative Study, 05 August 2022, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-1910181/v1]Background The present study aimed to assess the perceptions of patients with chronic diabetic foot ulcers (DFUs) and their informal caregivers regarding the impact of two stress reduction interventions, such as a progressive muscle relaxation and hypnosis, on patients’ DFU and psychological wellbeing. Methods This multicenter study used a qualitative exploratory design and included individual interviews with eight patients with chronic DFUs and six family caregivers, using a semi-structured interview guide. Transcripts analysis employed thematic content analysis. Results Four key themes common to patients and their caregivers were found: 1) perspectives regarding the intervention; 2) intervention effectiveness; 3) the role of psychology on the DFU treatment; and 4) emotions and consequences associated with the DFU. Although themes were common to both treatment groups, sub-themes from the last two themes differed for patients that received muscle relaxation versus those who received hypnosis. One additional theme emerged from the caregiver’s interviews: 5) promotion of self care behaviors. Conclusion According to patients and caregivers, overall the two stress reduction interventions were beneficial for the DFU healing progression and emotional wellbeing. The hypnosis group also reported lasting effects. Participants suggested that psychological interventions such as stress reduction interventions could be included in the DFU standard treatment as an adjuvant to the clinical protocol for DFU treatment, preferably offered early on, when the patient begins treatment at the diabetic foot consultation

Stress reduction interventions for patients with chronic diabetic foot ulcers: a qualitative study into patients and caregivers' perceptions

The present study aimed to assess the perceptions of patients with chronic diabetic foot ulcers (DFUs) and their family caregivers regarding the impact of two stress reduction interventions on DFU and psychological wellbeing. The intervention included progressive muscle relaxation and hypnosis sessions.This study was conducted at the Psychology Research Centre (CIPsi/UM) School of Psychology, the University of Minho, supported by the Foundation for Science and Technology (FCT) through an FCT grant (PTDC/PSIGER/28163/2017) assigned to the frst author

Simple and efficient furfural production from xylose in media containing 1-Butyl-3-Methylimidazolium hydrogen sulfate

The acidic 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim][HSO4]) ionic liquid was explored as both a reaction medium and a catalyst in the furfural production from xylose. Preliminary experiments were carried out at 100–140 °C for 15–480 min in systems containing just xylose dissolved in [bmim][HSO4] in the absence of externally added catalysts. More than 95% xylose conversion was achieved when operating at 120 or 140 °C for 300 and 90 min, respectively; but just 36.7% of the initial xylose was converted to furfural. Operation in biphasic reaction systems (in the presence of toluene, methyl-isobutyl ketone or dioxane as extraction solvents) at 140 °C under selected conditions resulted in improved furfural production (73.8%, 80.3%, and 82.2% xylose conversion to furfural for the cited extraction solvents, respectively)