Spectral Analysis of Flame Emission for Optimization of Combustion Devices on Marine Vessels

Chemiluminescent emission from OH*, CH* and C2* radicals and its dependence on the equivalence ratio is being investigated in the current study. The aim of this project is to use the results for combustion control on marine vessels and safety checks. The study was conducted in collaboration with Kockumation, a leading company in developing control systems for running boilers and steam turbines on marine vessels. Experiments were conducted at laboratory burners as well as an industrial burner, similar to the one that Kockumation uses. A new detection system for flame monitoring was suggested after the evaluation of the current detectors. The use of photodiodes were proven to be more reliable in detecting the chemiluminescent emission across a wide wavelength range (from UV to near IR region). Furthermore, after the analysis of the data, the CH*/OH* intensity ratio was evaluated as a calibration model for the prediction of the equivalence ratio. In addition to this, the partial least square regression (PLS-R) based multivariate calibration model was tested and the two models were compared. The latter model showed better accuracy in predicting Φ values. New experiments are also suggested for the investigation of additional species that are involved in the combustion process and the further optimization of combustion devices on marine vessels.Combustion processes play an important role in the energy efficiency worldwide. From a simple burner to a complete heating system, combustion is present in everyday life. In industry, especially, flame monitoring is crucial for quality control and safety checks. The spectral analysis of flame emission is widely used for the investigation of the equivalence ratio and its close-loop control. A high equivalence ratio value corresponds to a rich flame, where there is an excess of fuel that cannot be totally consumed during the combustion process. Furthermore, the molecular species involved in the combustion process can often contribute significantly to the understanding of the flame behavior. Molecular spectroscopy is regularly used for the identification of the molecules that are present in the reaction zone of the flame. Each molecule emits electromagnetic radiation at specific wavelengths, which is called chemiluminescence and is unique for a certain molecule. Molecules that obtain energy through chemical reactions emit the excess energy with the form of electromagnetic radiation and return to a more stable condition, i.e. ground state. This chemiluminescent emission is divided into different components, depending on their wavelength, by a spectrometer and can be detected with special cameras like the Intensified Charge-Coupled Device camera. In this thesis, the chemiluminescent emission of the flame was investigated in various burners in order to use the results for combustion control in steam generator systems for marine propulsion. This project was performed in collaboration with Kockumation, a leading company in this niche. Moreover, the performance of the current flame detection system of the company was studied and a new one was suggested. Further investigation could be contacted for the optimization of the existing combustion devices on marine vessels

‘THEY ARE MY FRIENDS!’ FINDINGS FROM AN ETHNOGRAPHIC STUDY ON YOUNG CHILDREN’S EXPERIENCES OF NURSERY PLAY AND LEARNING

Young children’s nursery play has been the focus of attention for years now focusing on the relationship between play and learning as well as the role of play in children’s overall development. In previous years most ‘play studies’ were concentrated on observing, recording, and analysing young children’s play from the adult’s perspective. However, recent studies aim to give young children voice and ownership on their play and learning experiences. In this respect, this paper is based on a small-scale ethnographic study and seeks to address the need for young children’s voices to be heard with regard to their nursery play experiences. A variety of audiovisual research methods (video camera, tape recorder, and still photographs) were employed for the collection and analysis of the data. The thematic analysis of the data suggests that young children’s play dialogues and comments on their nursery play can provide practitioners and other significant adults with rich and valuable insights into their views on play and learning within the early years’ settings. The themes that emerged included children’s experiences of play in terms of ownership, negotiation, learning, and preferences among others. In this respect, it is highlighted that young children’s voices added to the perspectives of their significant adults can help us form a complete picture of nursery play and learning with implications for the implementation of the early childhood curriculum.  Article visualizations

Temporal changes in the expression and distribution of adhesion molecules during liver development and regeneration

We have compared by immunocytochemistry and immunoblotting the expression and distribution of adhesion molecules participating in cell-matrix and cell-cell interactions during embryonic development and regeneration of rat liver. Fibronectin and the fibronectin receptor, integrin alpha 5 beta 1, were distributed pericellularly and expressed at a steady level during development from the 16th day of gestation and in neonate and adult liver. AGp110, a nonintegrin fibronectin receptor was first detected on the 17th day of gestation in a similar, nonpolarized distribution on parenchymal cell surfaces. At that stage of development haemopoiesis is at a peak in rat liver and fibronectin and receptors alpha 5 beta 1 and AGp110 were prominent on the surface of blood cell precursors. During the last 2 d of gestation (20th and 21st day) hepatocytes assembled around lumina. AGp110 was initially depolarized on the surface of these acinar cells but then confined to the lumen and to newly-formed bile canaliculi. At birth, a marked increase occurred in the canalicular expression of AGp110 and in the branching of the canalicular network. Simultaneously, there was enhanced expression of ZO-1, a protein component of tight junctions. On the second day postpartum, presence of AGp110 and of protein constituents of desmosomes and intermediate junctions, DGI and E-cadherin, respectively, was notably enhanced in cellular fractions insoluble in nonionic detergents, presumably signifying linkage of AGp110 with the cytoskeleton and assembly of desmosomal and intermediate junctions. During liver regeneration after partial hepatectomy, AGp110 remained confined to apical surfaces, indicating a preservation of basic polarity in parenchymal cells. A decrease in the extent and continuity of the canalicular network occurred in proliferating parenchyma, starting 24 h after resection in areas close to the terminal afferent blood supply of portal veins and spreading to the rest of the liver within the next 24 h. Distinct acinar structures, similar to the ones in prenatal liver, appeared at 72 h after hepatectomy. Restoration of the normal branching of the biliary tree commenced at 72 h. At 7 d postoperatively acinar formation declined and one-cell-thick hepatic plates, as in normal liver, were observed

Single-shot 3D imaging of hydroxyl radicals in the vicinity of a gliding arc discharge

Chemical processing by plasma is utilized in many applications. Plasma-related studies, however, are challenging to carry out due to plasmas' transient and unpredictable behavior, excessive luminosity emission, 3D complexity and aggressive chemistry and physiochemical interactions that are easily affected by external probing. Laser-induced fluorescence is a robust technique for non-intrusive investigations of plasma-produced species. The hydroxyl radical (OH) is an interesting molecule to target, as it is easily produced by plasmas in humid air. In this letter, we present 3D distributions of ground state OH radicals in the vicinity of a glow-type gliding arc plasma. Such radical distributions, with minimal plasma emission, are captured instantaneously in one single camera acquisition by combining structured laser illumination and a lock-in based imaging analysis method called FRAME. The orientation of the plasma discharge can be reconstructed from the 3D data matrix, which can then be used to calculate 2D distributions of ground state OH radicals in a plane perpendicular to the orientation of the plasma channel. Our results indicate that OH distributions around a gliding arc are strongly affected by gas dynamics. We believe that the ability to instantaneously capture 3D transient molecular distributions in a plasma discharge, with minimal plasma emission interference, will have a strong impact on the plasma community for in-situ investigations of plasma-induced chemistry and physics

Identification of a Bipotential Precursor Cell in Hepatic Cell Lines Derived from Transgenic Mice Expressing Cyto-Met in the Liver

Met murine hepatocyte (MMH) lines were established from livers of transgenic mice expressing constitutively active human Met. These lines harbor two cell types: epithelial cells resembling the parental populations and flattened cells with multiple projections and a dispersed growth habit that are designated palmate. Epithelial cells express the liver-enriched transcription factors HNF4 and HNF1α, and proteins associated with epithelial cell differentiation. Treatments that modulate their differentiation state, including acidic FGF, induce hepatic functions. Palmate cells show none of these properties. However, they can differentiate along the hepatic cell lineage, giving rise to: (a) epithelial cells that express hepatic transcription factors and are competent to express hepatic functions; (b) bile duct-like structures in three-dimensional Matrigel cultures. Derivation of epithelial from palmate cells is confirmed by characterization of the progeny of individually fished cells. Furthermore, karyotype analysis confirms the direction of the phenotypic transition: palmate cells are diploid and the epithelial cells are hypotetraploid. The clonal isolation of the palmate cell, an immortalized nontransformed bipotential cell that does not yet express the liver-enriched transcription factors and is a precursor of the epithelial-hepatocyte in MMH lines, provides a new tool for the study of mechanisms controlling liver development

Recombinant Laminins Drive the Differentiation and Self-Organization of hESC-Derived Hepatocytes

SummaryStem cell-derived somatic cells represent an unlimited resource for basic and translational science. Although promising, there are significant hurdles that must be overcome. Our focus is on the generation of the major cell type of the human liver, the hepatocyte. Current protocols produce variable populations of hepatocytes that are the product of using undefined components in the differentiation process. This serves as a significant barrier to scale-up and application. To tackle this issue, we designed a defined differentiation process using recombinant laminin substrates to provide instruction. We demonstrate efficient hepatocyte specification, cell organization, and significant improvements in cell function and phenotype. This is driven in part by the suppression of unfavorable gene regulatory networks that control cell proliferation and migration, pluripotent stem cell self-renewal, and fibroblast and colon specification. We believe that this represents a significant advance, moving stem cell-based hepatocytes closer toward biomedical application

Fibronectin acts as a molecular switch to determine SPARC function in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest of all solid tumours and more effective therapy is urgently needed. The stroma is thought to play a critical role in tumour development and metastasis, and high stromal expression of the matricellular protein SPARC has been robustly associated with poor patient prognosis. However, the precise role of SPARC has been highly controversial, with multiple studies demonstrating tumour-suppressor properties of this protein 'in vitro'. This conflicting data has been a barrier to the development of new therapeutic approaches targeting SPARC, despite current interest in stromal-therapy. We show conclusively that SPARC acts directly on cancer cells to promote pancreatic cancer cell proliferation. This contradicts previous 'in vitro' studies, but is consistent with the observed clinical association between SPARC expression and poor patient prognosis. However, depletion of fibronectin switches the activity of SPARC from promoting cancer cell proliferation to growth inhibition and induction of apoptosis. Thus, targeting the interaction between SPARC and fibronectin could be used to turn the highly expressed tumour protein SPARC against the tumour to induce tumour cytotoxicity, and is a novel target for PDAC therapy

Play in the nursery : an ethnographic study on the constructions of young children and their significant adults

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