Diplomová práca je zameraná na popísanie prúdenia tekutiny medzikruhovým potrubím. Tok tekutiny je skúmaný pri viacerých podmienkach, čo vedie k laminárnemu ale aj turbulentnému prúdeniu. Práca obsahuje rešeršnú časť, ktorá opisuje doteraz známe vzťahy popisujúce daný typ prúdenia a takisto skúma spôsoby merania rýchlostného profilu v medzikruhových medzerách. Nasledujúca časť obsahuje návrh výpočtového modelu, popis simulácií prúdenia pri konkrétnych podmienkach a ich vyhodnotenie. Výsledky zo simulačnej časti sú použité pri popise charakteristických vlastností turbulentného prúdenia v medzikruží. Tieto charakteristiky sú použité v ďalšej časti práce, ktorá je cielená na získanie analytického vzťahu, ktorý by popisoval časovo stredovaný rýchlostný profil turbulentného prúdenia v medzikruhovej medzere.

The main subject of this study is the improvement of predicative ability of previously developed mathematical model for prediction of so-called “fouling critical velocity”. Attention is devoted especially to the flue gas side fouling process on active heat transfer surfaces in tubular heat exchange tube banks installed in waste incineration process plants and also a technical – economic analysis based on obtained results. The model improvement consists among others in taking into account another forces (electrostatic, capillary etc.) haven't yet been considered, which influence the mutual contact between flue gas particles in case of sedimentation fouling or the contact between particles and heat exchanger tube walls respectively. The improved model has therefore more predicative ability to the reality of fouling process. The results are used for technical – economic analysis, which determines an optimal heat exchanger design with respect to fouling. Furthermore, the algorithm of this analysis, essential fouling mechanisms, fouled heat exchanger surface cleaning methods as well as fundamental knowledge of fouling coefficient prediction are presented, whereas the emphasis is placed on industrial tubular heat exchange equipment installed in waste incineration process plants.

Die Kryosphäre mit ihren großen Eisschilden und Gletschergebieten unterliegt seit einigen Jahrzehnten rasanten Veränderungen, deren Bestimmung überhaupt erst durch satellitengestützte Fernerkundungsmethoden ermöglicht wurde. Insbesondere die dynamischen Ausflussgletscher im Randbereich des Grönländischen Eisschildes verlieren an Eisdicke, ziehen sich zurück und zeigen eine beschleunigte Eisbewegung. Diese Arbeit widmet sich der Erstellung eines modular aufgebauten Monitoring-Systems zur überwiegend automatischen Bestimmung der Fließgeschwindigkeit und der Frontlage von Ausflussgletschern mit Hilfe von Landsat-Aufnahmen. Die frei verfügbaren Satellitendaten der Landsat-Mission sind dafür besonders geeignet, da sie nicht nur einen Beobachtungszeitraum von mehr als 40 Jahren umfassen, sondern nahezu im gesamten Bereich des Grönländischen Eisschildes mit einer hohen zeitlichen Auflösung vorliegen. Durch die Kombination unterschiedlicher Bildzuordnungsverfahren wurden flächendeckende Fließgeschwindigkeitsfelder der Ausflussgletscher bestimmt. Neben einem verbesserten Verfahren zur Ausreißerfilterung in den bestimmten Fließgeschwindigkeitsfeldern wurde ein automatisches Verfahren zur Steigerung der Koregistrierungsgenauigkeit entwickelt. Dies beinhaltet u. a. die Verbesserung der Orthorektifizierung mit Hilfe eines aus ASTER-Daten (Advanced Spaceborne Thermal Emission and Reflection Radiometer) erstellten, hochauflösenden Geländemodells. Die Geschwindigkeitsfelder wurden weiterhin um das den Geschwindigkeitsfeldern überlagerte Streifenmuster korrigiert, das durch die leicht zueinander verschobenen Scanzeilen in den Landsat-7-Aufnahmen ohne Scanzeilenkorrektur verursacht wurde. Neben der Bestimmung von Fließgeschwindigkeitsfeldern wurden zwei Verfahren zur Ableitung von Gletscherfrontlagen entwickelt. Der Fokus lag dabei auf der Bestimmung von Frontlagen in Eisfjorden, in denen Standardverfahren zur Gletscherflächenkartierung nur eingeschränkt nutzbar sind. Das erste Verfahren ermittelt die Gletscherfront anhand der Grauwertverteilung entlang mehrerer paralleler Profile, die im Übergangsbereich zwischen Eisfjord und Gletscherbereich liegen. Aus diesen Frontpositionen kann anschließend das Polygon der Gletscherfront vektorisiert werden. Das zweite Verfahren verfolgt einen Ansatz der überwachten Klassifikation, bei dem mit Hilfe von statistischen Texturmerkmalen die Segmentierung von Gletscherflächen erfolgt. Eine nahezu vollständige Auswertung aller verfügbaren Satellitendaten des Landsat-Archivs wurde für den Randbereich des Grönländischen Eisschildes durchgeführt. Auf einer Fläche von etwa 500000 km² wurden für 302 Gletscher Fließgeschwindigkeitsfelder bestimmt. Die überwiegend im Zeitraum 1999 bis 2012 vorliegenden Geschwindigkeitsfelder besitzen eine räumliche Auflösung von 300m x300m. Für etwa ein Drittel dieser Gletscher wurden über den gesamten Landsat-Missionszeitraum von 1972 bis 2012 zusätzlich auch die zeitlichen Änderungen der Frontlage ermittelt. Aus diesen Ergebnissen lassen sich sowohl der Langzeittrend als auch die saisonalen Variationen der Fließgeschwindigkeit und die Lage der Gletscherfront ableiten. Generell zeigen die Gletscher in Zentralwest-, Nordwest- und Südost-Grönland nicht nur höhere Fließgeschwindigkeiten im Vergleich mit den Gletschern in anderen Regionen Grönlands, sondern weisen oft auch ein deutlich beschleunigtes Fließverhalten auf. Die seit 1999 größten Veränderungen wurden am Jakobshavn Isbræ und am Upernavik Isstrøm im Westen sowie an einem Ausflussgletscher in der Køge Bugt im Südosten Grönlands beobachtet. Diese Gletscher zeigen einen jährlichen Geschwindigkeitsanstieg von mehr als 0,9 m/Tag. Neben den beobachteten Geschwindigkeitsänderungen ist häufig auch eine Variation der Frontlage zu beobachten. Gewöhnlich ist eine Beschleunigung des Gletschers mit einem Frontrückzug verbunden. Darüber hinaus weist ein Großteil der Gletscher eine ausgeprägte saisonale Variabilität ihrer Fließgeschwindigkeit und ihrer Frontlage auf. Die über mehrere Jahrzehnte vorliegende Zeitreihe der bestimmten Fließgeschwindigkeiten ermöglicht im Besonderen die Detektion und die Untersuchung des zeitlichen Verlaufs von Surge-Ereignissen.

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Yes / To reproduce the natural flow topography in a laboratory environment, it is crucial to recapture its bed condition in order to ensure the accurate representation. Water-worked bed represents a state-of-the-art experimentally formed bed to imitate the natural-formed channel in most rivers or natural streams. Recently, this technique has been intensively studied through experimental and computational approaches; however, its actual influence towards the near-bed flow as compared to experimentally prepared rough bed in well-packed bedform order are still yet to be investigated deeply. This experimental study systematically investigated and compared the differences in velocity distribution and three-dimensional (3D) turbulence characteristics, including turbulence intensities and Reynolds stresses, between uniform smooth bed, laboratory-prepared rough bed and water-worked bed open channel flows. The flow comparisons were concentrated at near-bed region where clear flow behaviour change can be observed. Through these comparisons, the study inspected the characteristics of water-worked bedform thoroughly, in order to inform future experimental research that tries to reproduce natural stream behaviours. / the Major State Basic Research Development Grant No. 2013CB036402 from Tsinghua University. The support from the Major State Basic Research Development Program (973 program) of China is also greatly appreciated. We also acknowledge the National Key Research and Development Project from the Ministry of Science and Technology during the Thirteenth Five-year Plan Period (Grant No. 2017YFC0403600) and the Science and Technology Projects State Grid Corporation of China (Grant No. 52283014000T).

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No / Injection moulding techniques have been miniaturised and refined to achieve micromoulding which aims to satisfy the need for mass production of low-cost micro- and nanoscale components. However, the microscale mould cavity features and extreme processing conditions which are inherent in the process can result in larger process variations than conventional injection moulding, with a corresponding increase in the probability of producing an unsatisfactory product. Accurate process diagnosis is required to ensure process reliability but integration of sensors onto the small and highly detailed mould units can be problematic and alternatives may need to be sought. Piezoelectric film ultrasonic transducers were integrated onto the extrusion barrel and mould insert of a micromoulding machine for real-time, non-destructive and non-intrusive process diagnosis with an ultrasonic pulse-echo technique. Polymer degradation owing to excessive heating at the extrusion barrel was successfully probed by measuring the ultrasonic velocities in the polymer at the mould insert. Filling incompleteness of the mould cavity was also sensitively detected by monitoring the ultrasonic energy variation transmitted into the part at different points along the melt flow length. The developed ultrasonic sensors and technique enable optimisation and in-process quality assurance of the moulded parts which ensures that maximum process efficiency can be achieved.

INTRODUÇÃO: Nos pacientes pediátricos, em razão das limitações relacionadas ao tamanho dos receptores, são utilizados segmentos do fígado provenientes de \"cadáver\" ou de doador vivo (\"fígado reduzido\"). As complicações decorrentes das anastomoses cirúrgicas podem ser de natureza vascular e biliar, sendo que a maior causa de perda do enxerto deve-se à trombose ou estenose da artéria hepática, veia porta e veias hepáticas. A ultra-sonografia convencional e com Doppler colorido (US-DC) pode ser utilizada para avaliação dessas complicações. Todavia, apesar da alta sensibilidade e especificidade deste método, há poucas descrições a respeito de parâmetros que podem ser utilizados para o estudo das alterações vasculares. OBJETIVO: Estabelecer parâmetros de ultra-sonografia convencional e com Doppler colorido (US-DC) para o diagnóstico de estenose da VP e VH no transplante hepático reduzido em crianças. MÉTODO: Estudo retrospectivo de 134 US-DC realizado em 48 crianças submetidas a transplante hepático segmentar no Instituto da Criança do Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo (ICr-HC-FMUSP), entre janeiro de 2002 e julho de 2005. No estudo da VP, os seguintes parâmetros foram analisados: calibre da VP na anastomose; velocidade máxima na anastomose (VP1); velocidade máxima no segmento pré-anastomose (VP2) e relação entre as velocidades máximas na anastomose/préanastomose (VP1/VP2). No estudo da VH, foram analisados: velocidade máxima na anastomose (VH1); velocidade na VH (VH2) e relação entre as velocidades máximas na anastomose/VH (VH1/VH2). Pacientes com estenose confirmada pela angiografia foram incluídos no grupo estenose e pacientes com angiografia ou cirurgia normal ou com boa evolução clínica foram incluídos grupo controle. RESULTADOS: Quatorze US-DC tiveram estenose da VP confirmadas pela portografia. O calibre da VP na anastomose foi menor no grupo estenose do que no grupo controle (média 2,5mm e 6,3mm respectivamente); PV1 e PV1/PV2 foram maiores no grupo estenose do que no grupo controle (média PV1 = 172cm/s, PV1/PV2 = 5,1 / PV1 = 83cm/s, PV1/PV2 = 1,8 respectivamente). O calibre da VP < 3,3mm apresentou a melhor correlação com a portografia (sensibilidade = 93% e especificidade = 88%), seguidos de VP1 > 128cm/s (sensibilidade = 86% e especificidade = 84%) e VP1/VP2 > 2,4 (sensibilidade = 79% e especificidade = 86%). Doze US-DC tiveram estenose da VH confirmada pela angiografia. A VH1 e HV1/VH2 foram maiores no grupo estenose do que no grupo controle (média VH1 = 202.2cm/s, VH1/VH2 = 6,0 / VH1 = 136,8cm/s, VH1/VH2 = 3,0 respectivamente). A relação VH1/VH2 > 4 apresentou a melhor correlação com a angiografia (sensibilidade = 83% e especificidade = 84%) seguido de VH1 > 128cm/s (sensibilidade = 83% e especificidade = 52%). CONCLUSÃO: Calibre da VP < 3,3mm na anastomose e relação das velocidades VH1/VH2 > 4 são altamente sensíveis e específicos no diagnóstico das estenoses da anastomose da VP e VH respectivamente, no póstransplante hepático em crianças / INTRODUCTION: Cadáveric split liver and living donor liver transplantation is mostly performed in children because of a shortage of suitable hepatic allograft in this population. Real time and Doppler ultrasound (CD-US) is the initial imaging modality for detection and follow-up of early and delayed vascular and non-vascular complications after liver transplant, but there are only few studies concerning its value in the diagnosis of venous complications. OBJECTIVE: Determine real time and Doppler ultrasound (CD-US) diagnostic parameters of portal (PV) and hepatic vein (HV) stenoses after segmental liver transplantation in children and assess their sensitivity and specificity. METHOD: Retrospective study of 134 CD-US performed in 48 patients submitted to segmental liver transplantation at Child Institute of University of Sao Paulo Medical School from January 2002 through July 2005. PV parameters: diameter at the anastomosis, velocities at the anastomosis (PV1) and at the pre-anastomosis segments (PV2) and the ratio PV1/PV2. HV parameters: velocities at the HV anastomosis to the inferior vena cava (HV1), at HV (HV2) and the ratio HV1/HV2. Stenosis group: patients with stenosis confirmed by angiography. Control group: patients presenting normal angiography or uneventhfull surgery or good clinical outcome. RESULTS: Fourteen CD-US had PV stenosis confirmed by portography. Diameter of PV at the anastomosis: narrower in the stenosis group (2.5mm) than in the control group (6.3mm) (p<.5). Mean PV1 and PV1/PV2: higher in the stenosis group than in the control group (PV1 = 172 cm/s, PV1/PV2 = 5.1/PV1 = 83cm/s, PV1/PV2 = 1.8). Statistical analysis determined as predictive of PV stenosis: PV diameter < 3.3mm (sensitivity of 93% and specificity of 88.4%); PV1 > 128cm/s (sensitivity of 86% and specificity of 84%) and PV1/PV2 > 2.4 (sensitivity of 79% and specificity of 86%). Twelve CD-US had HV stenosis confirmed by angiography. Mean HV1 and HV1/HV2: higher in the study group (HV1 = 202.2cm/s, HV1/HV2 = 6.0 / HV1 = 136.8cm/s, HV1/HV2 = 3.0) (p<.05). Statistical analysis determined as predictive of HV stenosis: PV1 > 128cm/s (sensitivity of 83% and specificity of 52%) and HV1/HV2 > 4 (sensitivity of 83% and specificity of 84%). CONCLUSION: PV diameter < 3.3mm at the anastomosis and HV1/HV2 > 4.0 are highly predictive for detection of PV and HV stenosis respectively, after pediatric segmental liver transplantation

Introdução: A cirurgia cardíaca resulta em taxa considerável de complicações neurológicas, incluindo delirium, disfunção cognitiva e acidente vascular cerebral isquêmico. Supõe que a fisiopatologia envolva embolia, aterotrombose, hipofluxo, redução do débito cardíaco e alterações da autorregulação cerebral. O balão de contrapulsação intra-aórtico (BIA) é um dispositivo de assistência circulatória comumente utilizado no perioperatório de pacientes de alto risco com o objetivo de otimização do débito cardíaco e da perfusão coronária. Apesar do benefício hemodinâmico do BIA, não é conhecido seu efeito na hemodinâmica encefálica. Objetivo: Avaliar os efeitos do BIA na hemodinâmica encefálica em pacientes de alto risco submetido a cirurgia cardíaca com circulação extracorpórea (CEC). Métodos: Trata-se de um subestudo do estudo clínico prospectivo e randomizado \"Balão de contra-pulsação intra-aórtico eletivo em pacientes de alto risco submetidos a cirurgia cardíaca\", realizado no Instituto do coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo entre 2014 e 2016. Dos 181 pacientes incluídos no estudo randomizado, 67 pacientes foram incluídos no subestudo. Os pacientes eram adultos, submetidos a cirurgia cardíaca de revascularização miocárdica (RM) com fração de ejeção menor ou igual a 40% e/ou EuroScore maior ou igual a 6. Os mesmos foram randomizados para uso do BIA logo após a indução anestésica ou para grupo controle. A velocidade de fluxo sanguíneo cerebral (VFSC) pelo ultrassom Doppler transcraniano e a pressão arterial (PA) pelo Finometer foram continuamente gravados por 5 minutos antes da cirurgia (T1), 24h após (T2) e 7 dias após (T3). O índice de autorregulação (ARI) foi estimado através da resposta ao degrau da VFSC a mudanças na PA, derivados da análise da função de transferência. As seguintes complicações clínicas neurológicas foram avaliadas: delirium, disfunção cognitiva e acidente vascular cerebral isquêmico. Resultados: Dos pacientes incluídos no estudo, 34 foram alocados para a estratégia de uso profilático do balão intra-aórtico e 33 para a estratégia controle. Não houve diferenças significativas entre os grupos BIA e controle respectivamente, nos três tempos de avaliação, em relação ao ARI (T1 - 5,5 ± 1,9 vs 5,7 ± 1,7; T2 - 4,0 ± 1,9 vs 4,1 ± 1,6; T3 - 5,7 ± 2,0 vs 5,7 ± 1,6, P= 0,978) e em relação à VFSC (T1 - 57,3 ± 19,4 vs 59,3 ± 11,8; T2 - 74,0 ± 21,6 vs 74,7 ± 17,5; T3 - 71,1 ± 21,3 vs 68,1 ± 15,1; P=0,952). O grupo BIA e o grupo controle apresentaram incidência semelhante de complicações neurológicas (delirium na unidade de terapia intensiva - 26,5% vs 24,2%, P=0,834, acidente vascular cerebral isquêmico - 3,0% vs 2,9%, P=1,00, e declínio cognitivo pós-operatório através das escalas Mini Mental State Examination MMSE - 16,7% vs 40,7%; P= 0,073 e Avaliação Cognitiva Montreal MoCA - 79,16% vs 81,5%; P= 1,000). Conclusões: O uso profilático do BIA em pacientes de alto risco submetidos à cirurgia de revascularização do miocárdio não altera a hemodinâmica encefálica e não está associado ao aumento de complicações neurológicas como delirium, declínio cognitivo e acidente vascular cerebral isquêmico / Introduction: Cardiac surgery is associated with a high incidence of neurologic complications, such as delirium, cognitive decline and stroke. The pathophysiology probably involves embolism, thrombosis, decreased cardiac output and abnormalities in cerebral autoregulation. The intraaortic balloon pump (IABP) is an assist device commonly in high-risk patients undergoing cardiac surgery aiming to increase the cardiac output and to improve the coronary perfusion. However, the effect of the IABP on the cerebral hemodynamic is unknown. Objectives: To assess the effect of IABP on cerebral hemodynamics in high-risk patients undergoing cardiac surgery with cardio-pulmonary bypass (CPB). Methods: This is a substudy of the randomized controlled trial \"Intraaortic Balloon Counterpulsation in Patients Undergoing Cardiac Surgery (IABCS trial)\", performed at the Heart Institute/University of Sao Paulo, from 2014 to 2016. Of the 181 patients included in the IABCS, 67 were included if they were submitted to cardiac surgery and if they had one of these two criteria: left ventricular ejection fraction equal or lower than 40% and/or EuroSCORE equal or higher than 6. Patients were allocated to the strategy of prohylatic IABP after anesthesia induction or to control. Cerebral blood flow velocity (CBFV) through transcranial Doppler and blood pressure (BP) through Finometer or intra-arterial line were continuously recorded over 5 minutes preoperatively (T1), after 24h (T2) and 7 days after surgery (T3). Autoregulation index (ARI) was estimated from the CBFV response to a step change in BP derived by transfer function analysis. The following complications neurologic were evaluated: delirium, cognitive decline and stroke. Results: Of the included patients, 34 were allocated to the IABP group and 33 to control group. There were no significant differences between the IABP and the control respectively in the following parameters: ARI (T1 - 5.5 ± 1.9 vs 5.7 ± 1.7; T2 - 4.0 ± 1.9 vs 4.1 ± 1.6; T3 - 5.7 ± 2.0 vs 5.7 ± 1.6, P= 0.978), CBFV (T1 - 57.3 ± 19.4 vs 59.3 ± 11.8; T2 - 74.0 ± 21.6 vs 74.7 ± 17.5; T3 - 71.1 ± 21.3 vs 68.1 ± 15.1; P=0.952). Both groups (IABP and control) had similar incidence of neurological complications (delirium - 26.5% vs 24.2%, P=0.834, stroke - 3.0% vs 2.9%, P=1.00, and cognitive decline through the scales Mini Mental State Examination MMSE - 16,7% vs 40,7%; P= 0.073 and Montreal Cognitive Assessment MoCA - 79.16% vs 81.5%; P= 1.000). Conclusions: The prophylactic use of IABP in high-risk patients undergoing cardiac surgery does not change the cerebral hemodynamic and is not associated with higher incidence of neurologic complications such as delirium, cognitive decline and stroke