Experimental analysis of flameless combustion for reduction of pollutants

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.This report presents a special form of combustion, called flameless combustion. In contrast to the combustion within stabilized flames, temperature peaks can be avoided at flameless combustion. Critical points of this technology are the realization of thermofluodynamic conditions which stabilize the flameless combustion process and a design to reach flameless conditions. Burners for flameless combustion usually show complex geometries which make simplified schemes difficult and inappropriate. In this case, the present paper proposes a study to determine the viability of a flameless burner design for experimental investigation and a combustion chamber on a laboratorial scale able to use high temperature air to reduce pollutant emissions. During the experiments, it will be used natural gas and preheat air. The influence of the field flow, chamber temperature and preheating air temperature on reaction zone volume was examined using techniques capable of analyzing the temperature field in the combustor. The main conclusions were: a) in contrast to the flames, the combustion had low internal temperature gradients; b) the system has promoted changes in the volume characteristics of combustion significantly reducing pollutants: NOx, CO and UHC (Unburned Hydrocarbons); c) to same conditions no visible flame was observed during the test.dc201

Suppression of tritium retention in remote areas of ITER by nonperturbative reactive gas injection

A technique based on reactive gas injection in the afterglow region of the divertor plasma is proposed for the suppression of tritium-carbon codeposits in remote areas of ITER when operated with carbon-based divertor targets. Experiments in a divertor simulator plasma device indicate that a 4¿¿nm/min deposition can be suppressed by addition of 1¿¿Pa·m3¿s-1 ammonia flow at 10 cm from the plasma. These results bolster the concept of nonperturbative scavenger injection for tritium inventory control in carbon-based fusion plasma devices, thus paving the way for ITER operation in the active phase under a carbon-dominated, plasma facing component background. © 2010 The American Physical Society

A biorefinery approach to the biomass of the seaweed Undaria pinnatifida (Harvey Suringar, 1873): obtaining phlorotannins-enriched extracts for wound healing

Brown seaweeds are recognized sources of compounds with a wide range of properties and applications. Within these compounds, phlorotannins are known to possess several bioactivities (e.g., antioxidant, anti-inflammatory, and antimicrobial) with potential to improve wound healing. To obtain phlorotannins enriched extracts from Undaria pinnatifida, a biorefinery was set using lowcost industry-friendly methodologies, such as sequential solid–liquid extraction and liquid–liquid extraction. The obtained extracts were screened for their antioxidant and antimicrobial activity against five common wound pathogens and for their anti-inflammatory potential. The ethanolic wash fraction (wE100) had the highest antioxidant activity (114.61 +- 10.04 mmol mg-1 extract by Diphenyl-1-picrylhydrazyl (DPPH) and 6.56 +-1.13mMeq. Fe II mg-1 extract by and Ferric Reducing Antioxidant Power (FRAP)), acting efficiently against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria, and showing a nitric oxide production inhibition over 47% when used at 0.01 ug mL-1. NMR and FTIR chemical characterization suggested that phlorotannins are present. Obtained fraction wE100 proved to be a promising candidate for further inclusion as wound healing agents, while the remaining fractions analyzed are potential sources for other biotechnological applications, giving emphasis to a biorefinery and circular economy framework to add value to this seaweed and the industry.info:eu-repo/semantics/publishedVersio

Opuntia ficus-indica seed pomace extracts with high UV-screening ability in a circular economy approach for body lotions with solar protection

Opuntia ficus-indica seed pomace, a by-product of seed oil extraction, was investigated due to its richness of phytochemical compounds and high antioxidant capacity. The pomace was subjected to hydrothermal extraction using water under subcritical conditions to solubilize various compounds. Different final heating temperatures 120 to 220 °C were applied, and the resulting filtered extracts were analyzed using HPLC and HPSEC to determine the monosaccharide profile and molecular weight of the oligomers. Notably, extractions performed at temperatures between 120 and 180 °C yielded extracts characterized by elevated levels of glucuronic acid and exhibited higher molecular weights. In contrast, extractions conducted at 200 and 220 °C were distinguished by their enriched xylose content and relatively low molecular weights, falling below 23.6 kDa. The extracts were tested for total phenolic compounds, as well as antioxidant activity using spectrophotometric methods such as TEAC, DPPH, and FRAP. Results showed that increasing temperature led to a corresponding increase in phenolic compounds (from 7.7 to 13.7 gGAE/100 g) and antioxidant activity, with the maximum observed at 200 °C. These phenolic compounds enriched extract were used to produce a body lotion with sun protection factor of 8, with rheological behavior similar to that of commercially available products but without the need for additional UV filters and antioxidants. The lotion was shown to be safe for topical use and did not cause skin irritation. This study highlights the potential of O. ficus-indica seed pomace as a valuable source of phytochemical compounds and demonstrates the feasibility of using hydrothermal extraction to produce eco-friendly commercially interesting compounds.Fundação para a Ciência e a Tecnologia | Ref. UIDB/50006/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/50006/2020Xunta de Galicia | Ref. ED481D-2022/018Xunta de Galicia | Ref. GRC-ED431C 2022/08Agencia Estatal de Investigación | Ref. TED2021-131555B-C22Agencia Estatal de Investigación | Ref. RYC2018-024454-IXunta de Galicia | Ref. ED431F 2020/0

Early life stage mechanisms of an active fish species to cope with ocean warming and hypoxia as interacting stressors

Ocean’s characteristics are rapidly changing, modifying environmental suitability for early life stages of fish. We assessed whether the chronic effects of warming (24 ◦C) and hypoxia (<2–2.5 mg L− 1 ) will be amplified by the combination of these stressors on mortality, growth, behaviour, metabolism and oxidative stress of early stages of the white seabream Diplodus sargus. Combined warming and hypoxia synergistically increased larval mortality by >51%. Warming induced faster growth in length and slower gains in weight when compared to other treatments. Boldness and exploration were not directly affected, but swimming activity increased under all test treatments. Under the combination of warming and hypoxia, routine metabolic rate (RMR) significantly decreases when compared to other treatments and shows a negative thermal dependence. Superoxide dismutase and catalase activities increased under warming and were maintained similar to control levels under hypoxia or under combined stressors. Under hypoxia, the enzymatic activities were not enough to prevent oxidative damages as lipid peroxidation and DNA damage increased above control levels. Hypoxia reduced electron transport system activity (cellular respiration) and isocitrate dehydrogenase activity (aerobic metabolism) below control levels. However, lactate dehydrogenase activity (anaerobic metabolism) did not differ among treatments. A Redundancy Analysis showed that ~99% of the variability in mortality, growth, behaviour and RMR among treatments can be explained by molecular responses. Mortality and growth are highly influenced by oxidative stress and energy metabolism, exhibiting a positive relationship with reactive oxygen species and a negative relationship with aerobic metabolism, regardless of treatment. Under hypoxic condition, RMR, boldness and swimming activity have a positive relationship with anaerobic metabolism regardless of temperature. Thus, seabreams may use anaerobic reliance to counterbalance the effects of the stressors on RMR, activity and growth. The outcomes suggests that early life stages of white seabream overcame the single and combined effects of hypoxia and warming.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Using plant wax markers to estimate the diet composition of grazing Holstein dairy cows

The objective of this study was to test whether diet selection of dairy cows under grazing conditions could be estimated using plant wax markers. Furthermore, differences between 2 cow strains and the effect of concentrate supplementation on plant species selection were investigated. The experiment was a study with a crossover design performed on an organic farm with 12 Swiss Holstein cows and 12 New Zealand Holstein cows. Both experimental periods consisted of a 21-d adaptation and a 7-d measurement period. All cows grazed full time in a rotational stocking system and received either no concentrate or 6 kg/d of a commercial cereal-grain mix. Representative herbage samples of each grazed paddock were taken and botanical composition of subsamples was manually determined. The average proportions of the plant species were 27.8% Lolium perenne, 6.1% Dactylis glomerata, 10.4% Trifolium repens, and 9.0% Taraxacum officinale. Other grass species were merged as "other grass" (38.2%) and other forb species as "other forbs" (8.5%). n-Alkanes, long-chain fatty acids, and long-chain alcohols (LCOH) were analyzed in the samples of plant species, concentrate, and feces from each cow. A linear discriminant analysis indicated that diet components were differentiated best with LCOH (96%) and worst with the combination of all marker groups together (12%). For each marker, the fecal marker recovery (FR) relative to dosed ytterbium was determined in 2 ways. Estimation of diet composition was performed with the software "EatWhat," and results were compared with botanical composition with the Aitchison distance. The results indicate that the diet composition of grazing dairy cows can be estimated using plant wax markers. Additionally, the calculation of FR led to mostly reliable results, yet this approach needs further validation. The most accurate estimation was achieved with the marker combination of n-alkanes and LCOH with a correction for FR. Less accurate estimations were achieved with long-chain fatty acids alone or in combination with n-alkanes. No difference relating to diet selection between the 2 cow strains was recorded, but supplemented cows apparently ingested higher proportions of T. repens than nonsupplemented cows. Awareness that supplementation influences selection behavior of grazing dairy cows may lead to adaptations in botanical composition of the pasture according to the demand of the animals

Impact of anthropogenic noise on the survival and development of meagre (Argyrosomus regius) early life stages

The growth of human populations has been driving an unprecedent and widespread increase in marine traffic, posing a real threat to marine biodiversity. Even though we are now aware of the negative effects of shipping noise exposure on fish, information about the impact on their early life stages continues to lack. Meagre (Argyrosomus regius) is a vocal fish that uses estuaries with high levels of anthropogenic noise pollution as both breeding areas and nurseries. Here, the effects of boat noise exposure on the development and survival of meagre larvae were studied. Embryos and larvae were exposed to either noise (boat noise playback) or control treatments (coils producing a similar electric field to the speakers) and hatching rate, survival rate, morphometric traits and stress-related biomarkers, at hatching and at 2 days-post-hatching (dph) were analyzed. Results showed no conclusive effects of the impact of boat noise playback, even though there was an increased lipid droplet consumption and a decrease in body depth at 2dph larvae under this stressor. The assessment of oxidative stress and energy metabolism-related biomarkers at hatching showed a marginal decrease in superoxide dismutase (SOD) activity and no changes in DNA damage or electron transport system activity (ETS), although it cannot be disregarded that those effects could only be visible at later stages of larval development. Whether these morphological and developmental results have implications in later stages remains to be investigated. Further studies with longer exposure and wild meagre could help deepen this knowledge and provide a better understanding of how anthropogenic noise can impact meagre early stagesFundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Prototipo funcional de un sistema de clasificación para las cerezas de café castillo, en función de su etapa de maduración

Trabajo de InvestigaciónEn el siguiente proyecto de grado se desarrolla un prototipo funcional para la clasificación automatizada de café castillo en función de su etapa de maduración, el cual consta de un sensor de color RGB, una banda transportadora, un servomotor para el desvió de las cerezas de café y el microcontrolador atmega328p. Inicialmente se realiza una búsqueda de las tecnologías que se emplean para este proceso, posterior a esto se selecciona los dispositivos que se usaran, ya con esto, se hace el modelado 3D del prototipo en el software Autodesk Inventor, se simula el sistema en Proteus y se diseña el circuito impreso (PCB) en EasyEDA, después de esto se realiza la implementación del prototipo para finalmente hacer las pruebas de validación.INTRODUCCIÓN 1. GENERALIDADES 2. METODOLOGÍA 3. DESCRIPCIÓN ECONÓMICA DEL PROYECTO 4. CONCLUSIONES 5. RECOMENDACIONES Y TRABAJOS FUTUROS BIBLIOGRAFÍA ANEXOSPregradoIngeniero Electrónic

Macromolecular theory of solvation and structure in mixtures of colloids and polymers

The structural and thermodynamic properties of mixtures of colloidal spheres and non-adsorbing polymer chains are studied within a novel general two-component macromolecular liquid state approach applicable for all size asymmetry ratios. The dilute limits, when one of the components is at infinite dilution but the other concentrated, are presented and compared to field theory and models which replace polymer coils with spheres. Whereas the derived analytical results compare well, qualitatively and quantitatively, with mean-field scaling laws where available, important differences from ``effective sphere'' approaches are found for large polymer sizes or semi-dilute concentrations.Comment: 23 pages, 10 figure