Emission Minimization of a Two-Stage Sour Water Stripping Unit Using Surrogate Models for Improving Heat Duty Control

Sour water are aqueous waste streams from oil refining operations, heavily contaminated with hydrogen sulfide and ammonia, which need to be stripped before reuse or disposal, avoiding damages to process and environment. Two-stage sour water stripper units are the most common technology to treat sour water for hydrogen sulfide and ammonia separation to produce reusable water and send these species respectively to Claus and ammonia plants. The first stage of a two-stage sour water unit is responsible for properly splitting hydrogen sulfide and ammonia. This work uses surrogate models to predict the limiting point of hydrogen sulfide separation in the first stage of a sour water unit, allowing more efficient heat duty control strategies to achieve the difficult split of hydrogen sulfide and ammonia and simultaneously lowering heat consumption. Failure of compliance to this limit results in unspecified stripped gas from the first stage, impeding it to directed to Claus plant, entailing loss of sulfur production and higher load of pollutant emissions from flared gases. Therefore, a precise surrogate predictor was developed to dynamically define a quasi-optimum set-point to the controller of the first stage reboiler duty based on dynamic disturbances – the first stage input factors to the surrogate model, such as hydrogen sulfide and ammonia contents of the sour water. The new control policy outperformed the traditional first stage ratio control in terms of stripped gas composition and plant stability

The use of body weight support on ground level: an alternative strategy for gait training of individuals with stroke

<p>Abstract</p> <p>Background</p> <p>Body weight support (BWS) systems on treadmill have been proposed as a strategy for gait training of subjects with stroke. Considering that ground level is the most common locomotion surface and that there is little information about individuals with stroke walking with BWS on ground level, it is important to investigate the use of BWS on ground level in these individuals as a possible alternative strategy for gait training.</p> <p>Methods</p> <p>Thirteen individuals with chronic stroke (four women and nine men; mean age 54.46 years) were videotaped walking on ground level in three experimental conditions: with no harness, with harness bearing full body weight, and with harness bearing 30% of full body weight. Measurements were recorded for mean walking speed, cadence, stride length, stride speed, durations of initial and terminal double stance, single limb support, swing period, and range of motion of ankle, knee, and hip joints; and foot, shank, thigh, and trunk segments.</p> <p>Results</p> <p>The use of BWS system leads to changes in stride length and speed, but not in stance and swing period duration. Only the hip joint was influenced by the BWS system in the 30% BWS condition. Shank and thigh segments presented less range of motion in the 30% BWS condition than in the other conditions, and the trunk was held straighter in the 30% BWS condition than in the other conditions.</p> <p>Conclusion</p> <p>Individuals with stroke using BWS system on ground level walked slower and with shorter stride length than with no harness. BWS also led to reduction of hip, shank, and thigh range of motion. However, this system did not change walking temporal organization and body side asymmetry of individuals with stroke. On the other hand, the BWS system enabled individuals with chronic stroke to walk safely and without physical assistance. In interventions, the physical therapist can watch and correct gait pattern in patients' performance without the need to provide physical assistance.</p

Gait training with partial body weight support during overground walking for individuals with chronic stroke: a pilot study

<p>Abstract</p> <p>Background</p> <p>It is not yet established if the use of body weight support (BWS) systems for gait training is effective <it>per se </it>or if it is the combination of BWS and treadmill that improves the locomotion of individuals with gait impairment. This study investigated the effects of gait training on ground level with partial BWS in individuals with stroke during overground walking with no BWS.</p> <p>Methods</p> <p>Twelve individuals with chronic stroke (53.17 ± 7.52 years old) participated of a gait training program with BWS during overground walking, and were evaluated before and after the gait training period. In both evaluations, individuals were videotaped walking at a self-selected comfortable speed with no BWS. Measurements were obtained for mean walking speed, step length, stride length and speed, toe-clearance, durations of total double stance and single-limb support, and minimum and maximum foot, shank, thigh, and trunk segmental angles.</p> <p>Results</p> <p>After gait training, individuals walked faster, with symmetrical steps, longer and faster strides, and increased toe-clearance. Also, they displayed increased rotation of foot, shank, thigh, and trunk segmental angles on both sides of the body. However, the duration of single-limb support remained asymmetrical between each side of the body after gait training.</p> <p>Conclusions</p> <p>Gait training individuals with chronic stroke with BWS during overground walking improved walking in terms of temporal-spatial parameters and segmental angles. This training strategy might be adopted as a safe, specific and promising strategy for gait rehabilitation after stroke.</p

Electrochemical study of nickel(salen) and cobalt(salen) derivatives complexes in the presence of unsaturated halides

The electrochemical intramolecular cyclisation of allyl 2-bromophenyl ethers in N,N'-dimethylformamide at constant current in a diaphragmless cell has been developed using Ni(II) and Co(II) complexes as electron-transfer mediators. Cyclic compounds are obtained in good yields under appropriate experimental conditions

Nature through the eyes of chemistry: characterization of novel active molecules from Azorean Natural Products

Jornadas "Ciência nos Açores – que futuro?", Ponta Delgada, 7-8 de Junho de 2013.A área de Química de Produtos Naturais tem contribuído, grandemente, para a descoberta de fármacos e agroquímicos, entre outros, por meio do isolamento de substâncias ativas produzidas por diversos organismos. As novas moléculas têm grande interesse científico, económico, social e farmacológico podendo contribuir, em muito, para a saúde das pessoas e para a sua qualidade de vida. O rastreio de novos compostos com atividade biológica tem sido, recentemente, uma das prioridades da comunidade científica e os Açores, pelas suas características particulares e endemismos assumem particular importância nesta área de investigação. O estudo das potencialidades de plantas e organismos marinhos dos Açores tem sido desenvolvido na Universidade dos Açores/CIRN desde a década de noventa, usando a estratégia de investigação seguinte: (i) seleção dos organismos mais promissores para fins industriais e comerciais pela avaliação da sua atividade em ensaios biológicos diversos, (ii) extração, separação e identificação dos compostos bioativos e (iii) estudos da relação estrutura-atividade dos compostos bioativos isolados.ABSTRACT: The chemistry of Natural Products has contributed greatly to the discovery of pharmaceuticals and agrochemicals agents, among others, by the isolation of active substances produced by various organisms. The new molecules are of great scientific, economic, social and pharmacological importance and may contribute greatly to the people's health and their quality of life. The screening for new compounds with biological activity has been a recent priority for the scientific community and the Azores, by its particular characteristics and endemism is of crucial importance in this area of research. The study of the Azorean plants and marine organisms potential has been investigated in Azores University/CIRN since the '90s decade, using the following research strategy: (i) screening of the most promising organisms for industrial and commercial purposes by evaluating their activity in several biological assays, (ii) extraction, purification and molecular structure elucidation of the bioactive compounds, and (iii) studies of structure-activity relationships of the isolated bioactive compounds

Impact of dietary inclusion of wine and olive oil waste extracts on physiological and health status of seabass (Dicentrarchus labrax)

Aquaculture is the only way to satisfy the growing global demand for seafood without depleting natural fisheries resources. Disease outbreaks are major threats to aquaculture production. The use of antibiotics or chemotherapeutics has been a common practice to combat infectious diseases that threaten production and induce high economic losses. This practice promotes high environmental harmful impacts and risks to human health (e.g., antibiotic-resistant bacteria). Thus, the development of nutritional strategies, such as natural functional supplements (FS) that preserve fish's health and well-being while preventing potential zoonotic disease and antibiotics use, is highly recommended to achieve the economical and sustainability of aquaculture. Wine and olive oil industry by-products (such as grape marc (GM) and olive pomace (OP)) are a source of high-value bioactive molecules, such as antioxidant and phenolic compounds. Thus, the valorisation of these agro-industrial by-products into new FS for aquafeeds is of high practical interest, contributing to the circular economy. The present study aims to evaluate the prospective beneficial effects of a previous optimised antioxidant-rich extract of a GM and OP mixture (WO) on seabass physiological and health status. For this purpose, two similar plant-based diets were formulated, including 0 (control diet) and 0.4% of WO extract (WO diet), corresponding to 0 and 91.1 of total antioxidants (m TE/g diet), respectively. After feeding seabass with these diets for ten weeks, the fish haematological, biochemical and immunological were assessed. The results demonstrated that 0.4% optimised WO extract decreases the mean corpuscular volume (control 159 ±53; WO 119± 9, p=0.042) in seabass. Other immunological parameters are being performed further to understand this extract's impact on seabass health status.Project SPO3 (ref.POCI-01-0145-FEDER-030377;FCT); project InovFeed(ref. MAR02.01.01-FEAMP-0111;Mar2020)info:eu-repo/semantics/publishedVersio

Electrochemical applications of electrolytes based on ionic liquids

The potential utility of room temperature ionic liquids as electrolytes in current electrochemical applications has been explored. Hence, the electrochemical behavior of [Ni(tmc)]Br2 complex at a glassy carbon electrode in the absence or in the presence of unsaturated halides in the ionic liquids, 1-ethyl-3- methylimidazolium ethylsulfate, [C2mim][C2SO4] and N,N,Ntrimethyl- N-(2-hydroxyethyl) ammonium bis(trifluoromethylsulfonyl)imide, [N1 1 1 2(OH)][NTf2], has been examined by cyclic voltammetry. It was observed that [Ni(tmc)]2+ complex is reduced in a reversible one-electron step and the electrogenerated [Ni(tmc)]+ complex catalytically reduces the carbon-halogen bond of unsaturated halides. The potencial use of natural ionic conducting polymer matrixes was also investigated. Samples of natural macromolecules-based electrolytes with the ionic liquid 1-ethyl- 3-methylimidazolium ethylsulfate, [C2mim][C2SO4], were prepared and characterized. The preliminary studies carried out with electrochromic devices (ECDs) incorporating optimized compositions have confirmed that these materials may perform as satisfactory multifunctional component layers in the field of ECD-based devices.Fundação para a Ciência e a Tecnologia (FCT

IPC02-27145 A TIME SERIES APPROACH FOR PIPE NETWORK SIMULATION

ABSTRACT We applied time series predicting tools for the simulation of the temporal behavior of large pipeline networks submitted to timely changing inputs. The inputs may consist of a set of specified flow rates at client or supply nodes, while the outputs are another set of nodal pressures and internal flow rates. According to the topology, size, age and history of the network, the continuous generation of phenomenological dynamic simulations may be impossible, imprecise or numerically expensive, demanding thus alternative approaches. Our methodology is particularly oriented to this kind of demand. From recorded network past data covering relevant history of inputs and selected outputs, ARX-MIMO predictors are built with identification methods and launched for continuous estimation of the network outputs one time step ahead. Results are precise enough for engineering, training and monitoring applications

Hypoglycemic and anti-lipemic effects of the aqueous extract from Cissus sicyoides

BACKGROUND: Cissus sicyoides (Vitaceae) is a medicinal plant popularly known in Brazil as "cipó-pucá, anil-trepador, cortina, and insulina". The plant is used in several diseases, including rheumatism, epilepsy, stroke and also in the treatment of diabetes. In the present work, we studied the hypoglycemic and anti-lipemic effects of the aqueous extract prepared from fresh leaves of the plant (AECS), in the model of alloxan-induced diabetes in rats. In addition, hepatic enzyme levels were also determined. RESULTS: Results showed that the daily treatment of diabetic rats with AECS for 7 days (100 and 200 mg/kg, p.o.) significantly decreased blood glucose levels in 25 and 22% respectively, as compared to the same groups before AECS treatment. No significant changes were seen in control diabetic rats before (48 h after alloxan administration) and after distilled water treatment. While no changes were seen in total cholesterol levels, a significant decrease was observed in plasma triglyceride levels, in the alloxan-induced diabetic rats after AECS treatment with both doses, as compared to the same groups before treatment. Significant decreases in blood glucose (25%) and triglyceride levels (48%) were also observed in the alloxan-induced diabetic rats after 4 days treatment with AECS (200 mg/kg, p.o.). Aspartate (AST) and alanine (ALT) aminotransferases levels, in diabetic controls and AECS-treated rats, were in the range of reference values presented by normal rats. CONCLUSIONS: The results justify the popular use of C. sicyoides, pointing out to the potential benefit of the plant aqueous extract (AECS) in alternative medicine, in the treatment of type 2 diabetes mellitus