An innovative implementation of the Herschel-Quincke tubes concept for the reduction of noise from turbofan engines is proposed here. The approach consists of installing circumferential arrays of Herschel-Quincke (HQ) tubes or waveguides in the inlet of the turbofan engine. An analytical technique was developed to predict the effects of HQ tubes applied to circular inlets. The modeling technique involves modeling the tubes-inlet interfaces as finite piston sources that couple the acoustic field inside the inlet with the acoustic field within the HQ tubes. An optimization technique based on genetic algorithms was also developed to be able to design and optimize the system parameters. The accuracy of the model was validated with experimental data obtained from two types of turbofan engines. Analytical predictions are shown to correlate well with experimental data. The analytical model is then used to provide insight into the noise control mechanisms involved in the system. It is shown that the energy in an incident mode is in part reflected back to the fan and that some energy is also scattered into other higher-order modes. Thus, the suppression of a particular mode is due to the combination of the scattered contributions from the various incident modes. The effects of the system parameters were analyzed and parametric studies were conducted. Different configurations for the arrays of HQ tubes such as helical patterns or tubes at an angle with respect to the inlet axis were also investigated. The results show the great potential of the HQ tubes system to reduce noise from turbofan engines. / Master of Science

Corrosion of reinforcing steel embedded in concrete due to the presence of moisture, aggressive chemicals, inadequate cover, and other factors can lead to deterioration that substantially reduces the strength and serviceability of the affected structure. Accounting for corrosion degradation is critical for evaluation and assessment of the load carrying capacity of existing reinforced concrete (RC) structures. However, little is known about the relationship between high strain rate blast loading and the degradation effects that govern corrosion damaged structures such as concrete cover cracking, reduction in reinforcement areas, and deterioration of bond between concrete and steel. Ten identical RC beams were constructed and tested, half under blast loading conditions produced using the Virginia Tech Shock Tube Research Facility and the other half under quasi-static loading. The blast tests were conducted to investigate how increasing blast pressure and impulse affect the global displacement response and damage modes of beams subjected to blast loads. The quasi-static tests were performed to establish fundamental data on the load-deflection characteristics of corroded RC beams. One beam from each testing group served as a control specimen and was not corroded while the remaining beams were subjected to varying levels of corrosion (5%, 10%, 15%, and 20%) of the longitudinal reinforcement along the midspan region. The specimens were corroded using an accelerated corrosion technique in a tank of 3% sodium chloride solution and a constant electrical current, creating a controlled environment for varying levels of corrosion. An analytical model was also created using a single degree of freedom (SDOF) approach which predicted the performance of corroded RC beams under blast loading. The results of the quasi-static tests revealed that as corrosion levels increased, the load to cause yielding decreased, the yield displacements decreased, and failure occurred earlier for all specimens. This was accompanied by increased damage to the concrete cover and the addition of longitudinal corrosion induced cracking. For the blast loaded specimens, the results demonstrated that the maximum displacements and residual displacements increased beyond the expected response limits for corrosion levels greater than 5%, but at corrosion levels less than 5% there was no significant change in displacements. Damage levels increased by one or more categories with the introduction of even small levels of corrosion of less than 5%. At corrosion levels greater than 5%, before loading was applied, the specimens exhibited moderate damage due to the introduction of corrosion induced cracking. After loading, the specimens sustained hazardous damage at progressively lower blast volumes. The failure mode changed from ductile to sudden and brittle failure at corrosion levels greater than 5% but remained ductile with flexural failures at low corrosion levels below 5%. The experimental results could be predicted with a high level of accuracy using the SDOF approach, provided that the degraded strength of corroded concrete cover, degraded mechanical properties of corroded steel, length of the corroded region, and determination of either uniform or pitting corrosion are accounted for. Overall, the introduction of corrosion to an RC beam subjected to blast loading resulted in decreased strength and ductility across all specimens but with most disastrous effects occurring at corrosion levels of 5% or greater. A recommendation is made to adjust the response limits in ASCE/SEI 59 to account for corrosion in RC beams. / Master of Science / The threat of blast loads, resulting from either terrorist attacks or accidental explosions, poses a significant threat to the structural integrity of buildings, life safety of occupants, and the functionality of the structure. Corrosion of reinforcing steel embedded in concrete, due to the presence of moisture, aggressive chemicals, and other factors, can lead to deterioration that substantially weakens the affected structure. Accounting for corrosion degradation is critical for evaluation and assessment of the strength of existing reinforced concrete structures. However, little is known about the effects of blast loading on the adverse nature that governs corrosion damaged structures. Ten identical reinforced concrete beams were constructed and tested, half under blast loading and the other half under quasi-static loading. The blast loaded beams were subjected to a series of increasing blast volumes until failure was reached. Five identical beams were tested under quasi-static loading to provide a baseline comparison against the blast loaded beams. One beam from each testing group served as a control specimen and was not corroded while the remaining beams were subjected to varying levels of corrosion of the steel reinforcement. An analytical model was also created to predict the performance of corroded reinforced concrete beams under blast loading. The results of the study showed that as corrosion levels increased, the displacements increased beyond the expected response limits. Damage levels became increasingly more severe with the introduction of corrosion at all levels. The behavior changed from ductile to brittle at corrosion levels greater than 5% but remained ductile with flexural failures at corrosion levels below 5%. Overall, the introduction of corrosion to a concrete beam subjected to blast loading resulted in decreased strength and ductility across all specimens but with most disastrous effects occurring at corrosion levels of 5% or greater. A recommendation is made to adjust the response the limits in the code to account for corrosion in reinforced concrete beams.

A fundamental study of the Herschel-Quincke (HQ) tube concept for the reduction of noise in circular ducts is presented here. Recent testing of the Herschel-Quincke tube concept on the Pratt-Whitney JT15D and AlliedSignal TFE731-60 engines showed the potential for the practical application of this approach. A model of the HQ-system has been developed to aid in the design of the system tested. The model has revealed new noise control mechanisms associated to the implementation of multiple HQ-waveguides in a duct in the presence of higher order modes. However, the practical nature of these engine facilities results in limitations with regard to the fundamental research knowledge that could be gained from testing in a more controlled laboratory environment. A series of experiments was conducted at the NASA Langley Research Center 0.30 m ducted fan test facility where detailed modal measurements were performed. The main goals of this research endeavor were to evaluate the accuracy of the previously developed theoretical model and provide insight into the noise control mechanisms. Experiments were performed with different disturbance mode structures, number of HQ tubes and arrays, and axial positions. The modes in the duct were generated with an array of acoustic drivers (no flow case) and measured with logarithmically spaced circumferential and helical microphone arrays located on the duct wall. The modal amplitudes of the incident, transmitted, and reflected modes in the duct were determined from the microphone measurements. This allowed for the comparison of analytical and experimental modal amplitudes, modal powers, total power, and reductions. The results of this study provide insight into the three noise control mechanisms associated with this approach: reflection, circumferential scattering, and radial scattering. Comparison with the experimental results shows that the model accurately predicts the sound power attenuation except near the cut-off frequency of the modes where it tends to overestimate the attenuation. The effect of the number of tubes in the array and its axial position was also evaluated. Overall, the results of this study validate the general modeling approach for the HQ tube concept. / Master of Science

La littérature actuellement disponible visant à explorer la physiologie du tube digestif des larves de la mouche soldat noire (Hermetia illucens) est incapable de caractériser l'ensemble du corps des larves. La méthodologie d'histologie utilisant soit de la paraffine soit de la résine époxy permet d'observer la morphologie cellulaire. De plus, elle ne préserve pas les aspects physiologiques des tissus comme les enzymes. La méthode de substitution par congélation est préconisée car elle minimise la dénaturation des protéines et préserve les enzymes dans leur état réactif après incorporation dans le méthacrylate de glycol. La cuticule des insectes présente généralement un obstacle pour les processus histologiques car les échanges de liquides à travers cette barrière sont limités. Ainsi, la perforation de cette membrane est essayée pour permettre l'inclusion. Différentes méthodes de pré-traitements et de déshydratation sont utilisées dans ce travail afin optimiser le protocole d'inclusion du glycol méthacrylate. Les coupes histologiques obtenues ont été soumises à une coloration enzymatique afin de localiser ces protéines dans le tube digestif des larves. La qualité des lames histologiques obtenues a été évaluée sur la base de la conservation, de la fragilité des tissues et de la quantité corps gras présent dans la larve. La perforation de la chitine ne présente aucun effet bénéfique sur la qualité des lames produites. En revanche, la substitution par congélation suivie de l'inclusion de méthacrylate s'est révélé être une méthode viable pour des applications histologiques sur les larves d'insectes. Les résultats montrent qu'une composante de la trypsine liée à la membrane est localisée dans la partie postérieure de l'intestin moyen, tandis que les composantes de l'α-galactosidase soluble et liée à la membrane sont localisées dans la partie antérieure de l'intestin moyen. La trehalase n'a pas pu être localisée dans le tube digestif des larves en raison d'un protocole défectueux. / The current literature aimed at exploring the digestive physiology of the larvae of the black soldier fly (Hermetia illucens) is unable to characterise the whole body of the larvae. These studies have either used paraffine or epoxy, which are sufficient for observing cell morphology, however these methods do not preserve certain aspects of the physiology such as enzymes. Freeze-substitution followed by subsequent embedding in glycol methacrylate is a preferable method as it minimizes protein denaturation and preserves enzymes in their reactive-state. The cuticle of insects commonly presents an obstacle for histological processes, as the sclerotized chitin prevents liquid exchange, the puncturing of the chitin is one way to circumvent this issue. Larvae were subjected to no pre-treatment, puncturing the chitin before or after freezing or the removal of the chitin and daily dehydrations to optimise the embedding protocol, upon optimising this protocol the sections were subjected to enzyme staining for localizing enzymes in the digestive tract, to localize the enzyme activity in the digestive tract. The slides were evaluated based on the preservation, brittleness of the tissue and on the relative amount of fat body present in the insect. The puncturing of the chitin was found to have no beneficial effect on the quality of the slides produced, freeze-substitution and methacrylate inclusion were shown to be a viable method for histological applications on these larvae. Furthermore, a membrane-bound version of trypsin was localized in the posterior part of the midgut, whereas both the solubilized and membrane-bound versions of α-galactosidase were localized within the anterior part of the midgut, trehalase was unable to be localized, most likely due to a faulty protocol.

<p>This is a master thesis conducted at KTH Centre for Naval Architecture in collaboration with Wallenius Marine AB.</p><p>Rolling motions is something that is undesired in all kinds of seafaring. In terms of propulsion resistance, comfort and route planning it would be desirable to reduce these motions. This thesis is an investigation on how different roll stabilising systems affect the performance of an 8000 unit PCTC vessel, special emphasis is put on investigating the performance of anti roll tanks. The ship in question has a recorded incidence of parametric rolling and the ability of the tanks to countervail this phenomenon is also investigated.</p><p>The tank and fin stabilising systems are relatively equal when it comes to roll damping performance related to changes in the required forward propulsion power. The tanks however, have a higher potential for improvements, addition of features such as heeling systems and parametric roll prevention systems.</p><p>The tank performance is also independent of the speed of the ship. The tanks are easier to retrofit and do not require the ship to be put in dry dock during installation. The conclusion of this thesis is that a combined anti roll and heeling system should be installed but that a further study has to be made on the performance of active rudder stabilisation.</p><p>It is shown that passive tanks are efficient at preventing parametric rolling in some sea states. A proposal is made for a further study on a control system that could achieve the same performance for all sea states.</p> / <p>HTML clipboard Detta är ett examensarbete utfört på KTH Marina System i samarbete med Wallenius Marine AB.</p><p>Rullningsrörelser är något som är oönskat i all form av sjöfart. Framsteg kan göras i både framdrivningsmotstånd, komfort och ruttplanering om dessa rörelser kunde minskas. Detta examensarbete består av en undersökning hur olika system för rulldämpning påverkar prestandan hos ett 8000 enheters PCTC-fartyg. Speciell vikt har lagts vid att undersöka prestandan hos antirulltankar. Det undersökta fartyget har en dokumenterad incident med parametrisk rullning och tankarnas förmåga att motverka detta fenomen undersöks.</p><p>Tank- och fenstabilisatorer är i princip likvärdiga vad det gäller dämpningsprestanda relaterat till erforderliga ändringar i framdrivningseffekten. Tankarna har dock en större potential för förbättring och tillägg av ytterligare inslag som krängningshämmare och system för motverkan av parametrisk rullning. Tankarnas prestanda är också oberoende av fartygets fart.</p><p>Tankarna är lättare att installera i efterhand och kräver inte att fartyget läggs i torrdocka under installationen. Slutsatsen av detta arbete är att en kombinerad antirull- och krängningshämmande tank bör installeras men att en vidare studie måste göras på prestandan hos aktiva roderstabiliseringssystem.</p><p>Det visas att passiva tankar kan motverka parametrisk rullning i vissa sjötillstånd. Ett förslag om en vidare studie på reglersystem som skulle kunna ge samma prestanda vid alla sjötillstånd ges.</p><p> </p>

Approved for public release; distribution is unlimited / The construction of an apparatus for the condensation performance testing of a horizontal bundle of four tubes with various refrigerants was completed. The apparatus was instrumented, and data reduction software was developed to provide bundle and single tube condensation data. Two tube bundles were tested, smooth copper tubes and low integral-fin copper-nickel tubes, with two refrigerants, R-114 and R-113. An enhancement ratio of about 2.0 for the overall heat transfer coefficient was demonstrated for the finned tubes over the smooth tubes. Internal contamination, possibly due to a breakdown of the refrigerant molecules when subjected to high temperatures in the boiling chamber, inhibited further meaningful data collection. Recommendations for improvement of the test apparatus are made. / http://archive.org/details/condensationofre00mabr / Lieutenant, United States Navy

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Frente a crescente necessidade de se monitorar diferentes contaminantes em matrizes complexas se faz necessário utilizar uma etapa de preparo de amostras eficiente e que esteja aliada à técnicas analíticas de elevada sensibilidade. Consequentemente, vem se aprimorando e desenvolvendo novos materiais sorventes utilizados para aumentar o desempenho do preparo de amostras e de fases estacionárias para cromatografia líquida de alta eficiência. Atualmente, materiais sorventes seletivos como líquidos iônicos, polímeros impressos molecularmente, grafeno, entre outros, vêm se destacando para extrair diferentes contaminantes. Diante desse contexto, esta tese teve como objetivo desenvolver diferentes materiais extratores para serem utilizados na microtécnica de extração in-tube SPME acoplada on-line com UPLC-MS/MS na análise de triazinas e sulfonamidas em matrizes complexas. O material que apresentou maior seletividade pelas classes dos compostos de interesse foi caracterizado por microscopia eletrônica de varredura e espectroscopia vibracional na região do infravermelho. Tanto para as triazinas quanto para as sulfonamidas o polímero impresso molecularmente apresentou maior afinidade e foi utilizado como fase extratora para extrair e pré-concentrar os analitos utilizando a microténica in-tube SPME UPLC-MS/MS. Além disso, para as triazinas utilizou-se também como fase de extração óxido de grafeno ancorado em sílica. As metodologias desenvolvidas nessa tese foram todas otimizadas e posteriormente validadas para analisar as matrizes de interesse que foram: uva, suco de uva integral, leite e água. Após à validação, as amostras foram analisadas com seus respectivos métodos validados, sendo que nenhum dos analitos foram encontrados considerando-se os limites das metodologias desenvolvidas, as quais se mostraram eficientes quando aplicadas nas análises das triazinas e sulfonamidas em suas respectivas amostras fortificadas. Outra abordagem explorada nesse trabalho foi o desenvolvimento de colunas tubulares abertas do tipo PLOT para serem utilizadas como colunas de extração em sistemas automatizados na cromatografia líquida. Colunas de sílica fundida foram preparadas para avaliar a formação da fase e sua aderência na parede do tubo. Para as colunas PS-DVB, os melhores resultados foram obtidos com duas horas de polimerização em banho de água. No entanto, para as colunas ODS a polimerização foi feita utilizando forno, e a fase não aderiu corretamente na parede do tubo para as colunas de 250 &mu;m de diâmetro interno, requerendo estudos mais aprofundados para o preparo adequado destas colunas. / In view of the increasing need to monitor different contaminants in complex matrices, it is necessary to use efficient sample preparation techniques combined with highly sensitive analytical techniques. Consequently, new sorbent materials have been improved and developed to be used aiming to increase the performance of sample preparation and stationary phases for high performance liquid chromatography. Currently, selective sorbents such as ionic liquids, molecularly imprinted polymers, graphene, among others, have been emphasized to extract different contaminants. In this context, this thesis aimed to develop different extractive materials to be used in in-tube solid phase microextraction coupled on-line with UPLC-MS/MS in the analysis of triazines and sulfonamides in complex matrices. The material that presented greater selectivity for the classes of the compounds of interest was characterized by scanning electron microscopy and vibrational spectroscopy in the infrared region. For triazines and sulfonamides the molecularly imprinted polymer had higher affinity and was used as the extractive phase to extract and preconcentrate the analytes using the in-tube SPME UPLC-MS/MS. In addition, another extraction phase - graphene oxide anchored in silica - was also used. The methodologies developed in this thesis were all optimized and later validated to analyze the target compounds in the following matrices: grape, grape juice, milk and water. After the validation, the samples were analyzed with their respective validated methods and none of the analytes were found considering the limits of the methodologies developed, which were efficient when applied in the analysis of the triazines and sulfonamides in their respective fortified samples. Another approach explored in this work was the development of open tubular columns (PLOT) to be used as extraction columns in automated sample preparation - liquid chromatography systems. Silica columns were prepared in order to evaluate the formation of the phase and its adhesion to the tube wall. For the PS-DVB columns the best results were obtained with two hours of water-bath polymerization. However, for the ODS columns the polymerization done using an oven the phase did not adhere correctly in the tube wall the columns with 250 &mu;m internal diameter. These results suggest that further experiments are required in order to better understand the preparation of these columns.

Frente a crescente necessidade de se monitorar diferentes contaminantes em matrizes complexas se faz necessário utilizar uma etapa de preparo de amostras eficiente e que esteja aliada à técnicas analíticas de elevada sensibilidade. Consequentemente, vem se aprimorando e desenvolvendo novos materiais sorventes utilizados para aumentar o desempenho do preparo de amostras e de fases estacionárias para cromatografia líquida de alta eficiência. Atualmente, materiais sorventes seletivos como líquidos iônicos, polímeros impressos molecularmente, grafeno, entre outros, vêm se destacando para extrair diferentes contaminantes. Diante desse contexto, esta tese teve como objetivo desenvolver diferentes materiais extratores para serem utilizados na microtécnica de extração in-tube SPME acoplada on-line com UPLC-MS/MS na análise de triazinas e sulfonamidas em matrizes complexas. O material que apresentou maior seletividade pelas classes dos compostos de interesse foi caracterizado por microscopia eletrônica de varredura e espectroscopia vibracional na região do infravermelho. Tanto para as triazinas quanto para as sulfonamidas o polímero impresso molecularmente apresentou maior afinidade e foi utilizado como fase extratora para extrair e pré-concentrar os analitos utilizando a microténica in-tube SPME UPLC-MS/MS. Além disso, para as triazinas utilizou-se também como fase de extração óxido de grafeno ancorado em sílica. As metodologias desenvolvidas nessa tese foram todas otimizadas e posteriormente validadas para analisar as matrizes de interesse que foram: uva, suco de uva integral, leite e água. Após à validação, as amostras foram analisadas com seus respectivos métodos validados, sendo que nenhum dos analitos foram encontrados considerando-se os limites das metodologias desenvolvidas, as quais se mostraram eficientes quando aplicadas nas análises das triazinas e sulfonamidas em suas respectivas amostras fortificadas. Outra abordagem explorada nesse trabalho foi o desenvolvimento de colunas tubulares abertas do tipo PLOT para serem utilizadas como colunas de extração em sistemas automatizados na cromatografia líquida. Colunas de sílica fundida foram preparadas para avaliar a formação da fase e sua aderência na parede do tubo. Para as colunas PS-DVB, os melhores resultados foram obtidos com duas horas de polimerização em banho de água. No entanto, para as colunas ODS a polimerização foi feita utilizando forno, e a fase não aderiu corretamente na parede do tubo para as colunas de 250 &mu;m de diâmetro interno, requerendo estudos mais aprofundados para o preparo adequado destas colunas. / In view of the increasing need to monitor different contaminants in complex matrices, it is necessary to use efficient sample preparation techniques combined with highly sensitive analytical techniques. Consequently, new sorbent materials have been improved and developed to be used aiming to increase the performance of sample preparation and stationary phases for high performance liquid chromatography. Currently, selective sorbents such as ionic liquids, molecularly imprinted polymers, graphene, among others, have been emphasized to extract different contaminants. In this context, this thesis aimed to develop different extractive materials to be used in in-tube solid phase microextraction coupled on-line with UPLC-MS/MS in the analysis of triazines and sulfonamides in complex matrices. The material that presented greater selectivity for the classes of the compounds of interest was characterized by scanning electron microscopy and vibrational spectroscopy in the infrared region. For triazines and sulfonamides the molecularly imprinted polymer had higher affinity and was used as the extractive phase to extract and preconcentrate the analytes using the in-tube SPME UPLC-MS/MS. In addition, another extraction phase - graphene oxide anchored in silica - was also used. The methodologies developed in this thesis were all optimized and later validated to analyze the target compounds in the following matrices: grape, grape juice, milk and water. After the validation, the samples were analyzed with their respective validated methods and none of the analytes were found considering the limits of the methodologies developed, which were efficient when applied in the analysis of the triazines and sulfonamides in their respective fortified samples. Another approach explored in this work was the development of open tubular columns (PLOT) to be used as extraction columns in automated sample preparation - liquid chromatography systems. Silica columns were prepared in order to evaluate the formation of the phase and its adhesion to the tube wall. For the PS-DVB columns the best results were obtained with two hours of water-bath polymerization. However, for the ODS columns the polymerization done using an oven the phase did not adhere correctly in the tube wall the columns with 250 &mu;m internal diameter. These results suggest that further experiments are required in order to better understand the preparation of these columns.

Au cours de ce projet de thèse, j’ai étudié le lien fonctionnel entre la morphogénèse épithéliale et la signalisation Delta-Notch, dans le cadre de la formation du tube neural chez le poisson-zèbre. La signalisation Delta-Notch est primordiale pour le développement embryonnaire et le maintien de l’homéostasie des tissus adultes. De façon inattendue, j’ai observé suite à la perte-de-fonction de Mib une perte de la polarité apico-basale dans le neuro-épithélium de la moelle épinière embryonnaire. L’analyse plus poussée de ce phénotype m’a ensuite permis de montrer que l’activité de l’intégralité de la signalisation Notch est requise pour l’établissement de la polarité apico-basale dans le tube neural de poisson-zèbre. En effet, l’inhibition des ligands de Notch et des activateurs transcriptionnels situés en aval, Rbpja et Rbpjb, résulte en l’interruption de la polarité apico-basale. De plus, l’activation ectopique de Notch entraîne un sauvetage complet de la polarité apico-basale dans les embryons déplétés pour Mib. Finalement, le mutant Mib échoue à activer la transcription de protéines de polarité apicale Crumbs1 et Crumbs2a au cours de la formation du tube neural, ce qui suggèrerait que la signalisation Notch agit en amont des complexes de polarité. De façon surprenante, nous avons également montré que le composant de la signalisation Notch, Mib, affecte les mouvements de convergence-extension et la division cellulaire orientée, appelée C-divisions, durant la neurulation et la gastrulation à travers la signalisation PCP. Cet effet de Mib sur la PCP est indépendant de son rôle sur la signalisation Notch. Généralement, cette étude révèle un double-rôle de Mib. / In this Ph.D. project, I study the functional link between epithelial polarity and Delta-Notch signaling in the context of zebrafish neural tube morphogenesis. Notch signaling, one of the major signaling pathways and of prime importance in neurogenesis, has been widely studied for its function in cell fate specifications. Surprisingly, I found that the Notch signaling component Mindbomb (Mib) loss-of-function led to a loss of apico-basal polarity in the neuroepithelium of the embryonic spinal cord. I further explored that the activity of the entire Notch signaling pathway is actually required for the earliest steps of establishment of apico-basal polarity in the zebrafish neural tube. Indeed, inhibition of Notch ligands and downstream transcriptional activators Rbpja and Rbpjb resulted in a disruption of apico-basal polarity. Moreover, ectopic activation of Notch ensued to a complete rescue of apico-basal polarity in Mib loss of function embryos. Furthermore, Mib mutant embryos fail to upregulate the transcription of the apical polarity proteins Crumbs1 and Crumbs2a in the course of neural tube formation, suggesting that Notch signalling might act upstream of polarity complexes. Moreover, I found that Mib affects convergent-extension movements and oriented cell divisions during neurulation and gastrulation through an effect on planar cell polarity. Remarkably, this effect of Mib on PCP is independent of its role in Notch signaling. These results indicate a novel role of Mib in the regulation of PCP signaling. Altogether, this study revealed a dual role of Mib in the epithelial morphogenesis of the zebrafish neural tube.