Dissertations / Theses on the topic 'Humidity of the process gass'

The overall goal of the presented dissertation thesis was to study the sterilization efficiency of dielectric barrier discharge operated at atmospheric pressure. The fungi Aspergillus niger, gram-positive bacteria Bacillus subtilis and in some experiments also gram-negative bacteria Escherichia coli were used as a bio-indicator enabling to evaluate the effect of plasma assisted microbial inactivation. The samples of microorganism were placed on paper Whatman 1 or PET foil and exposed to plasma. The plasma was generated in argon, nitrogen, synthetic dry/humid air with frequency up to 10 kHz and plasma power density in the range of 1,2-2,9 W/cm3 (according to the process gas). The influence of process gas, plasma power density, plasma exposition time, type of microorganism and material of the substrate on the sterilization effect of dielectric barrier discharge was evaluated. Furthermore the contribution of each single mechanism (UV radiation, temperature and reactive species) to the sterilization effect of plasma and influence of gas humidity was evaluated. The DBD was analysed by means of optical emission spectroscopy, thermocouple was used to measure temperature during a sterilization process. In order to verify the mechanical damage of the microbial cell or the substrates during the plasma process the samples were studied by scanning electron microscopy. Generally, on the basis of experimental results, at increasing treatment times, the remaining number of spores (CFU) decreased. Similarly at increasing the plasma power input, the sterilization rate increased. When sterilising the spores of A. niger in plasma using different process gasses, the efficiency of plasma sterilization decreased as follows: argon, humid synthetic air, nitrogen and dry synthetic air. The results observed in argon plasma using different microorganism demonstrated that the sensitivity of vegetative cells resp. spores to DBD decreased as follows: A. niger spores, B. subtilis vegetative cells, E. coli vegetative cells and B. subtilis spores. Simultaneously results observed for sterilization of spores and vegetative cells of B. subtilis and A. niger demonstrated that the spores are generally more resistant to plasma than are the corresponding vegetative cells. Combining the results of contribution of each single mechanism, optical emission spectroscopy and inactivation characteristic it was found out that the reactive species significantly contribute to the plasma sterilization in all process gasses. Furthermore the inactivation process can be partly assisted by UV radiation and also the temperature can contribute in limited extent to inactivation process in some gasses. The contribution of UV radiation to the plasma sterilization decreased as follows: nitrogen, argon, dry syntetic air and humid syntetic air. Moreover it was found out that the contribution of each single mechanism can be species dependent, this is due to the different response of microorganism to the unfavorable external conditions. SEM analysis of the substrates prooved the etching actions of the plasma generated in all process gasses on the surface of the PET foil. The several minute plasma exposition of the PET foil resulted in the occurence of the „hole corrosion“ on the PET surface. Contrary to these there were no visible changes observed in the paper structure.

L'élimination des polluants d'un mélange gazeux est un enjeu majeur en termes de réduction de l'impact environnemental de nombreux procédés industriels. Les liquides ioniques sont des solvants de remplacement prometteurs pour les composés organiques traditionnels utilisés dans la séparation sélective en raison de leur pression de vapeur négligeable et de leurs propriétés chimico-physiques concevables. Dans cette étude, un nouveau concept, la combinaison des IL et d'une membrane céramique tubulaire (ILM), a été développé dans le but de séparer les gaz ou les liquides des flux d'alimentation. Par rapport aux procédés classiques d'élimination des gaz ou des liquides, les ILM offrent une grande stabilité et une résistance mécanique élevée pendant une longue période de fonctionnement. Dans le cas des traitements de gaz, l'élimination de l'humidité pour protéger le capteur de gaz et le traitement du gaz industriel contenant du toluène sont les deux parties développées dans ce manuscrit. Les effets de plusieurs paramètres de fonctionnement, notamment le débit de gaz, la température, la pression, la concentration d'alimentation, la surface effective de la membrane (longueur de la membrane de support) et la position des canaux de gaz, ont été étudiés à la fois sur l'élimination de l'humidité et du toluène (vapeur). En outre, un modèle mathématique en deux étapes a été utilisé pour simuler les résultats expérimentaux et évaluer la performance de séparation des MIL dans les conditions de fonctionnement proposées. Selon les résultats expérimentaux et simulés, les ILM présentaient une capacité d'absorption relativement élevée de l'humidité et du toluène. Ce nouveau procédé ILM sera le procédé vert dominant pour la séparation des polluants gazeux ou liquides
The removal of pollutants from a gas mixture is a major issue in terms of minimizing the environment impact of numerous industrial processes. Ionic liquids are promising alternative solvents for traditional organic compounds using in selective separation due to their negligible vapor pressure and designable chemic-physical properties. In this study, a new concept, combination of ILs and a tubular ceramic membrane (ILM), has been developed with the aim of gas or liquid separation from feed streams. Comparing to conventional gas or liquid removal processes, ILMs provide high stability and mechanical resistance during long-time operation. Moreover, specific properties of ILs ensure selectivity and absorption capacity of ILMs. In the case of gas treatments, removal of humidity to protect gas sensor and treatment of industrial gas containing toluene are the two parts developed in this manuscript. Effects of several operating parameters, including gas flow rate, temperature, pressure, feed concentration, effective surface area of membrane (length of the support membrane) and position of gas channels, were investigated both on humidity and toluene (vapor) removal. In addition, a two-step model was used to simulate experimental results and evaluate the separation performance of ILMs. According to both experimental and simulated results, ILMs exhibited relative high absorption capacity of humidity and toluene. This new ILM process will be the dominating green processes for gas or liquid pollutants separation

Die Bildung von Anlauffarben durch molekularen Sauerstoff im Wurzelschutzgas ist bereits gut erforscht. Weitere Sauerstoffquellen für die Bildung von Anlauffarben sind Feuchte und CO2. Besonders Feuchte ist in diesem Zusammenhang kritisch, da sie sich wesentlich langsamer mit den etablierten Mitteln entfernen lässt. Im Rahmen dieser Arbeit konnte für durch Feuchte verursachte Anlauffarben im Wurzelschutzgas ein Grenzwert von 300 ppm bei 23 °C ermittelt werden. Die Farbausprägung der durch Feuchte verursachten Anlauffarben tendiert besonders bei schwachen bis mittleren Ausprägungen (450-800 ppm) stärker ins Bräunliche als die durch molekularen Sauerstoff verursachten Anlauffarben. Mit Hilfe des an der TU Dresden entwickelten Algorithmus für die Auswahl von Gaskomponenten für Prozessgase, wurde für das gepulste WIG-Orbitalschweißverfahren von austenitischen CrNi-Stahlrohren das Gasgemisch Ar/He/H2 20/70/10 ausgewählt. Gegenüber dem ursprünglich als Prozessgas verwendeten Argon und einem Ar/He 70/30 Gemisch, zeigte sich eine mögliche Steigerung der Vorschubgeschwindigkeit um den Faktor 3,5. Bei Fragen und Anmerkungen zur Arbeit sowie beim Verfassen einer weiterführenden Arbeit bitte Kontakt mit dem Autor aufnehmen (gerd.hauser@gmx.de). Dieser ist an einer Weiterführung des Themas sowie einer unabhängigen Überprüfung der Messwerte sehr interessiert
The formation of annealing colors by molecular oxygen in the backing gas is already well understood. Other sources of oxygen for the formation of annealing colors are humidity and CO2. Moisture is especially critical in this context, since they can be removed much more slowly with the established agents. As part of this work can be set a limit for annealing colors (caused by moisture in the root protection gas) of 300 ppm moisture with a environment temparatur of 23 ° C. The annealing colors caused by humidity tends especially in low to moderate conzentrtions (450-800 ppm) mor to a brownish than the annealing colors caused by molecular oxygen. Using the algorithm developed at the TU Dresden for the selection of gas components for process gases,the gas mixture Ar/He/H2 20/70/10 was chosen for the pulsed TIG orbital welding of austenitic stainless steel tubes. Compared to the originally used process gas argon and Ar/He-mixture 70/30, showed the Ar/He/H2 mixtur a possible increase in feed rate by a factor of 3.5

Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka consists of six 18V46 Wartsila turbocharged air cooled engines. Specific fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days. This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity. The effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. It was confirmed the specific fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the losses in the flue gas reduce in night time comparatively to the day time. Finally it can be concluded that under the prevailing ambient conditions in Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity on the combustion process. Therefore, proper cleaning and maintaining of the charge air coolers are the most important factors to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value.

På uppdrag av Högskolan i Gävle

Cette thèse est consacrée à la simulation du comportement à la rupture de bois sous des chargements à long terme et sous des conditions d'Humidité Relatives (HR) de l'air variables. Il est connu que le bois est un matériau fortement hygroscopique, ses propriétés mécaniques et de rupture sont en effet très dépendantes de sa teneur en eau. En outre, la stabilité d'une fissure existante dans un élément structural peut être fortement influencée parles variations, en particulier brusques, d'humidité relative qui peut conduire à la rupture inattendue de l'élément.L'approche thermodynamique proposée intègre l'effet de mécanosorption dans l'expression analytique de la déformation, en découplant les déformations mécaniques et celles dues au comportement mécanosorptif du matériau. En outre, la rupture quasi-fragile du matériau boisest traduite par un modèle de zone cohésive dont les paramètres de cohésion sont fonctions de la teneur en eau afin de simuler l’effet de l'humidité sur les propriétés de rupture. Sur cette base, une formulation incrémentale permet l'intégration de l'effet des variations soudaines d’humidité relative (autrement dit, le choc hydrique) sur la zone d’élaboration(zone cohésive) en introduisant un champ de contraintes supplémentaires le long de cette zone. Fonction de la variation de HR, ce champ de contraintes supplémentaires dépend de l'état de contrainte et de l'ouverture de la fissure le long de la zone cohésive, mais également de l'humidité en pointe de fissure (matériau non endommagé). Dans l'analyse par éléments finis, un opérateur tangent algorithmique est utilisé pour résoudre le problème non linéaire en combinant le modèle de mécanosorption et le modèle de zone cohésive et en intégrant l'effet du choc hydrique.La simulation du comportement d'une éprouvette entaillée soumise à un chargement constant et à des variations cycliques de HR montre un fort couplage entre le comportement mécanosorptif et l'effet du choc hydrique HR sur la zone d’élaboration. Ce couplage entraîne une augmentation de la propagation des fissures et conduit à une fissuration plus précoce par rapport à celle obtenue à partir du modèle de mécanosorption seul ou à partir du modèle de zone cohésive en intégrant l'effet des variations soudaines de HR. En outre, le couplage entre le modèle mécanosorptif et le modèle de zone cohésive en intégrant l'effet du chochydrique montre l'intérêt d'une telle approche numérique pour décrire le comportement complexe des éléments de charpente en bois soumis à des conditions climatiques variables,comportement qui ne peut être prédit par une simple superposition des deux modélisations
This thesis is dedicated to the simulation of the fracture behavior of wood under long-termloading and variable relative humidity conditions. Indeed, wood is well-known to be a highlyhygroscopic material in so far as its mechanical and fracture properties are very dependenton moisture. Moreover, the stability of an existent crack in a structural element can bestrongly affected by the sudden variations of relative humidity (RH) and can lead tounexpected failure of the element.The thermodynamic approach proposed in this thesis includes the mechano-sorptive effect inthe analytical expression of the deformation, by operating a decoupling of the strain in amechanical part and a mechano-sorptive part in material. Moreover, the quasi-brittle fractureof wood is here simulated from a cohesive zone model whose cohesive parameters arefunctions of the moisture in order to mimic the moisture-dependent character of the fractureproperties. On this basis, an increment formulation allows the integration of the effect ofsudden RH variations on the fracture process zone (cohesive zone) by introducing anadditional stress field along this zone. As a function of the RH variation, this additional stressfield depends on not only the stress state and the crack opening along the cohesive zone butalso the material moisture ahead of the zone (undamaged material). In the finite elementanalysis, an algorithmic tangent operator is used to solve the non-linear problem combiningmechano-sorptive model and cohesive zone model including the effect of sudden RHvariations.The simulation of a notched structural element submitted to a constant load and cyclic RHvariations exhibits a strong coupling between the mechano-sorptive behavior and the effectof the RH variations on the fracture process zone (FPZ). This coupling results in an increaseof the crack propagation kinetic and leads to a precocious failure compared to those obtainedfrom the mechano-sorptive model or from the effect of sudden RH variations on the FPZ.Moreover, the coupling between the mechano-sorptive model and the effect of sudden RHvariations on the FPZ which cannot be predicted by a simple superposition of both effects,showing the interest of such a numerical approach in order to describe the complex behaviorof wood structural elements submitted to variable climatic conditions

The diploma thesis deals with the thermal-humidity stress of the wooden wall. The work is focused on the connection of the wall to the base structure of the building. Three details were chosen. The work was focused on detail with the most common structure of an external wall used in the Czech Republic on the composition with a supporting structure made of KVH columns, which are filled with mineral insulation. This construction is covered with plate elements. The insulation from the exterior is made of ETICS with expanded polystyrene thermal insulation. This detail was assessed in the software. To compare the results calculated by real-time software, an experimental model was made, which was subjected to experimental measurements. Part of the diploma thesis is a comparison of detail stress under different boundary design conditions, with or without anchoring.

The integrity of nearly all engineering structures are threatened by the presence of cracks. Structural failure occurs if a crack larger than a critical size exists. Although most well designed structures initially contain no critical cracks, subcritical cracks can grow to failure under fatigue loading, called fatigue crack growth (FCG). Because it is impossible or impractical to prevent subcritical crack growth in most applications, a damage tolerant design philosophy was developed for crack sensitive structures. Design engineers have taken advantage of the FCG threshold concept to design for long fatigue lives. FCG threshold (DKth) is a value of DK (crack-tip loading), below which no significant FCG occurs. Cracks are tolerated if DK is less than DKth. However, FCG threshold is not constant. Many variables influence DKth including microstructure, environment, and load ratio. The current research focuses on load ratio effects on DKth and threshold FCG. Two categories of load ratio effects are studied here: extrinsic and intrinsic. Extrinsic load ratio effects operate in the crack wake and include fatigue crack closure mechanisms. Intrinsic load ratio effects operate in the crack-tip process zone and include microcracking and void production. To gain a better understanding of threshold FCG load ratio effects (1) a fatigue crack closure model is developed to consider the most likely closure mechanisms at threshold, simultaneously, and (2) intrinsic load ratio mechanisms are identified and modeled. An analytical fatigue crack closure model is developed that includes the three closure mechanisms considered most important at threshold (PICC, RICC, and OICC). Crack meandering and a limited amount of mixed-mode loading are also considered. The rough crack geometry, approximated as a two-dimensional sawtooth wave, results in a mixed-mode crack-tip stress state. Dislocation and continuum mechanics concepts are used to determine mixed-mode crack face displacements. Plasticity induced crack closure is included by modifying an existing analytical model, and an oxide layer in the crack mouth is modeled as a uniform layer. Finite element results were used to verify the analytical solutions for crack-tip stress intensity factor and crack face displacements. These results indicate that closure for rough cracks can occur at two locations: (1) at the crack-tip, and (2) at the asperity nearest the crack-tip. Both tip contact and asperity contact must be considered for rough cracks. Tip contact is more likely for high Kmax levels, thick oxide layers, and shallow asperity angles, a. Model results indicate that closure mechanisms combine in a synergistic manner. That is, when multiple closure mechanisms are active, the total closure level is greater than the sum of individual mechanisms acting alone. To better understand fatigue crack closure where multiple closure mechanisms are active (i.e. FCG threshold), these interactions must be considered. Model results are well supported by experimental data over a wide range of DK, including FCG threshold. Closure-free load ratio effects were studied for aluminum alloys 2024, 7050, and 8009. Alloys 7050 and 8009 were selected because load ratio effects at FCG threshold are not entirely explained by fatigue crack closure. It is believed that closure-free load ratio mechanisms occur in these alloys. Aluminum alloy 2024 was selected for study because it is relatively well behaved, meandering most load ratio effects are explained by fatigue crack closure. A series of constant Kmax threshold tests on aluminum alloys were conducted to eliminate fatigue crack closure at threshold. Even in the absence of fatigue crack closure load ratio (Kmax) effects persist, and are correlated with increased crack-tip damage (i.e. voids) seen on the fatigue crack surfaces. Accelerated FCG was observed during constant Kmax threshold testing of 8009 aluminum. A distinct transition is seen the FCG data and is correlated with a dramatic increase in void production seen along the crack faces. Void production in 8009 aluminum is limited to the specimen interior (plane-strain conditions), promoting crack tunneling. At higher values of Kmax (+_ 22.0 MPaà m), where plane-stress conditions dominate, a transition to slant cracking occurs at threshold. The transition to slant cracking produces an apparent increase in FCG rate with decreasing DK. This unstable threshold behavior is related to constraint conditions. Finally, a model is developed to predict the accelerated FCG rates, at higher Kmax levels, in terms of crack-tip damage. The effect of humidity (in laboratory air) on threshold FCG was studied to ensure that environmental effects at threshold were separated from load ratio effects. Although changes in humidity were shown to strongly affect threshold FCG rates, this influence was small for ambient humidity levels (relative humidity between 30% and 70%). Transient FCG behavior, following an abrupt change in humidity level, indicated environmental damage accumulated in the crack-tip monotonic plastic zone. Previous research implies that hydrogen (a component of water vapor) is the likely cause of this environmental damage. Analysis suggests that bulk diffusion is not a likely hydrogen transport mechanism in the crack-tip monotonic plastic zone. Rather, dislocation-assisted diffusion is presented as the likely hydrogen transport mechanism. Finally, the (extrinsic) fatigue crack closure model and the (intrinsic) crack-tip damage model are put in the context of a comprehensive threshold model. The ultimate goal of the comprehensive threshold model is to predict fatigue lives of cyclically loaded engineering components from (small) crack nucleation, through FCG, and including failure. The models developed in this dissertation provide a basis for a more complete evaluation of threshold FCG and fatigue life prediction. The research described in this dissertation was performed at NASA-Langley Research Center in Hampton, Virginia. Funding was provided through the NASA GSRP program (Graduate Student Researcher Program, grant number NGT-1-52174).
Ph. D.

碩士
中原大學
機械工程研究所
105
Graphene oxide (GO) prepared from various modified Hummers method was used as anti-corrosion barrier and humidity sensor. In this study, different manufacturing process and drying method was compared to different material properties. The surface morphology, crystallinity, dispersibility, defect degrees and functional group were observed by using scanning electron microscopy, X-ray diffraction, zeta potential analyzer, RAMAN and FT-IR spectra. The result of material properties showed the oxidation degree difference from manufacture process. Graphene oxide was then deposited on stainless steel substrate by electrophoretic deposition. The graphene oxide film served as a anti-corrosion barrier layer, protecting steel from corrosion media. The high charge transfer impedance of graphene oxide inhibited the occurrence of chemical corrosive reactions. Graphene oxide also had the competitive low price compared to those existing anti-corrosion coating. On the other hand, this study used graphene oxide and quartz crystal microbalance as humidity sensor. Graphene oxide with higher oxidation degrees was full of hydroxyl. It helped capture lots of water molecules that enhance the sensitivity of humidity sensor. The result would be proved by using frequency counter and impedance spectroscopy.

碩士
元智大學
化學工程與材料科學學系
94
The quality of photonic band gap (PBG) films produced using colloidal silica particles under different sedimentation environments was studied. The fabricating procedure includes particle syntheses, powder suspension and sedimentation. Results show that the higher quality of the PBG films was fabricated in higher relative humidity (RH) controlled conditions and low alcohol-content solvents. In addition, the surface tension and particle concentration were also influential factors to affect the PBG crystal growth. From the result of design of experimental (DOE), the final period of the sedimentation process was verified as the most influential stage of the formation of the PBG films. The optimal operating conditions of the PBG crystal fabrication were determined using the DOE data and the optimization approach. The minimum time of fabricating the high quality of PBG film was obtained under the optimum RH-Controlled conditions.

Only 2.5% of the water on Earth is fresh water and only less than 1% is accessible to human consumption. Landlocked and desert communities and communities that are not wealthy enough to provide clean drinking water via conventional water treatment technologies are facing severe water shortages and tend to rely on long distance transportation to supply fresh water for their daily use. As a lot of the water-scarce countries have abundant annual solar irradiation and relatively high humidity, this project proposes a technology that harvests water from ambient air using an anhydrate salt and releases it for collection using sunlight. This technology is designed to be potentially deployed in night-day cycles, as the humidity at night is at its peak, and solar irradiation during the day is also at its peak. In this work, a mesoporous silica powder filled with CuCl2 and coated with carbon nanotubes is used. The water capture performance of this material was investigated with different relative humidity environments. Furthermore, the powder agglomeration sizes of this material were also investigated for each relative humidity environment. Water release was investigated under 1 kW/m2 simulated solar light in an in-lab ~60% relative humidity environment. The results show that this mesoporous material was able to capture water at 12% relative humidity conditions, low enough to capture water from the air in the Sahara Desert. At relative humidity of 15% and 35%, the material was able to absorb 0.12 and 0.25 kg/kg of water, respectively, within 100 minutes, which indicates its fast water harvesting kinetics. A fully hydrated sample released 0.26 kg/kg of water in almost half an hour under 1 kW/m2 simulated sunlight. This project sheds more light on utilizing the atmosphere as an alternative water source.

The use of composite materials in the naval industry has been increasing especially over the last decades. The shipbuilding industry tends to use composite materials due to their low weight and good mechanical properties, typically in the construction of ship hulls. Since 2015, Arsenal do Alfeite, SA has been developing and building composite materials vessels, such as the construction of the Fiberglass Reinforced Polymer (FGRP) Coastal Patrol Boats. Thus, arise the need to understand the variation of the properties of the material during the lifespan and to study its degradation. In this study, the part of the hull considered the zone of interest was the one subject to the most severe conditions in the marine environment. Thus, the aim of this dissertation is to study the effect of the most critical factors on material degradation by comparing three distinct conditions: as currently produced, with and without paint coating, and the proposal for improvement through the addition of silica nanoparticles to the resin on the interface between composite material and PVC core. The most critical parameters for degradation were identified, namely ultraviolet radiation and humidity. The addition of silica nanoparticles to the resin aims to reduce the permeability of the interface layer and improve the material performance with respect to UV absorption in order to increase the material life. The set of specimens, produced by infusion, consisted on simulating the characteristics of the currently produced hull, the addition of 2 wt% nano-silica and the addition of nano-silica together with a layer of silicone paint. Monolithic specimens with original characteristics and nano-silica addition were also made. These specimens were tested in the accelerated aging chamber for 1000 hours. After the aging process, the degree of degradation of the specimens was identified and compared by visual and microscopic analysis of the areas of interest, and 3-point bending tests were performed to identify changes in the mechanical properties. A lower degradation level and improved mechanical properties were observed in the specimens with nano-silica addition. It was concluded that the addition of nano-silica increases the mechanical properties and marine life of glass fibre reinforced polymers which can be considered a competitive advantage in the marine industry.

Die Bildung von Anlauffarben durch molekularen Sauerstoff im Wurzelschutzgas ist bereits gut erforscht. Weitere Sauerstoffquellen für die Bildung von Anlauffarben sind Feuchte und CO2. Besonders Feuchte ist in diesem Zusammenhang kritisch, da sie sich wesentlich langsamer mit den etablierten Mitteln entfernen lässt. Im Rahmen dieser Arbeit konnte für durch Feuchte verursachte Anlauffarben im Wurzelschutzgas ein Grenzwert von 300 ppm bei 23 °C ermittelt werden. Die Farbausprägung der durch Feuchte verursachten Anlauffarben tendiert besonders bei schwachen bis mittleren Ausprägungen (450-800 ppm) stärker ins Bräunliche als die durch molekularen Sauerstoff verursachten Anlauffarben. Mit Hilfe des an der TU Dresden entwickelten Algorithmus für die Auswahl von Gaskomponenten für Prozessgase, wurde für das gepulste WIG-Orbitalschweißverfahren von austenitischen CrNi-Stahlrohren das Gasgemisch Ar/He/H2 20/70/10 ausgewählt. Gegenüber dem ursprünglich als Prozessgas verwendeten Argon und einem Ar/He 70/30 Gemisch, zeigte sich eine mögliche Steigerung der Vorschubgeschwindigkeit um den Faktor 3,5. Bei Fragen und Anmerkungen zur Arbeit sowie beim Verfassen einer weiterführenden Arbeit bitte Kontakt mit dem Autor aufnehmen (gerd.hauser@gmx.de). Dieser ist an einer Weiterführung des Themas sowie einer unabhängigen Überprüfung der Messwerte sehr interessiert.:1 Einleitung 1 2 Stand der Technik 2 2.1 WIG-Schweißen 2 2.1.1 Gepulstes WIG-Schweißen 2 2.1.2 WIG-Orbitalschweißen 5 2.2 Schweißen von austenitischem CrNi-Stahl 7 2.2.1 Schweißtechnische Verarbeitung von austenitischem CrNi-Stahl 7 2.2.2 Schweißnahtunregelmäßigkeit: Anlauffarben 12 2.3 Prozess- und Wurzelschutzgase 17 2.3.1 Prozessgase 18 2.3.2 Wurzelschutzgase 21 2.4 Messung von Sauerstoff und Feuchte bei schweißtechnischen Anwendungen 23 3 Präzisierung der Aufgabenstellung 28 4 Analyse von Baustellenbedingungen und Maßnahmen auf Winterbaustellen 29 4.1 Beschreibung der Bedingungen 29 4.2 Beschreibung der Unregelmäßigkeiten 31 4.3 Bewertung der etablierten Maßnahmen 33 5 Versuchsplanung und Durchführung 35 5.1 Experimentelle Randbedingungen 35 5.1.1 Geräte, Messmittel und Software 35 5.1.2 Versuchswerkstoffe und Materialien 42 5.1.3 Schweißparameter 43 5.1.4 Auswertungsmethoden 44 5.2 Einfluss der Feuchte in Wurzelschutzgasen 47 5.2.1 Schweißversuche bei konstanten und wechselnden Temperaturen 47 5.2.2 Versuche zur Feuchteansammlung im Rohr 49 5.2.3 Versuch zur Bildung von Anlauffarben bei unterschiedlichen Feuchtekonzentrationen im Wurzelschutzgas 51 5.3 Einfluss der Prozessgaszusammensetzung für die Gasgemische Ar, Ar/He, Ar/He/H2 53 6 Auswertung der Versuchsergebnisse und Schlussfolgerungen 56 6.1 Anlauffarben auf Winterbaustellen 56 6.1.1 Einfluss der Außentemperatur auf den Schweißprozess 56 6.1.2 Einfluss von Feuchteansammlungen in Rohren 61 6.1.3 Einfluss von unterschiedlichen Feuchtekonzentrationen im Wurzelschutzgas 63 6.1.4 Schlussfolgerungen für die Anwendung in der Praxis 68 6.2 Einfluss der Prozessgaszusammensetzung beim WIG-Orbitalschweißen 74 6.2.1 Versuchsauswertung 74 6.2.2 Anwendung des Mischgases Ar/He/H2 in der Praxis 80 7 Zusammenfassung und Ausblick 81 8 Quellenverzeichnis 82 9 Verzeichnis der Abbildungen und Tabellen 87 10 Anlagenverzeichnis 92
The formation of annealing colors by molecular oxygen in the backing gas is already well understood. Other sources of oxygen for the formation of annealing colors are humidity and CO2. Moisture is especially critical in this context, since they can be removed much more slowly with the established agents. As part of this work can be set a limit for annealing colors (caused by moisture in the root protection gas) of 300 ppm moisture with a environment temparatur of 23 ° C. The annealing colors caused by humidity tends especially in low to moderate conzentrtions (450-800 ppm) mor to a brownish than the annealing colors caused by molecular oxygen. Using the algorithm developed at the TU Dresden for the selection of gas components for process gases,the gas mixture Ar/He/H2 20/70/10 was chosen for the pulsed TIG orbital welding of austenitic stainless steel tubes. Compared to the originally used process gas argon and Ar/He-mixture 70/30, showed the Ar/He/H2 mixtur a possible increase in feed rate by a factor of 3.5.:1 Einleitung 1 2 Stand der Technik 2 2.1 WIG-Schweißen 2 2.1.1 Gepulstes WIG-Schweißen 2 2.1.2 WIG-Orbitalschweißen 5 2.2 Schweißen von austenitischem CrNi-Stahl 7 2.2.1 Schweißtechnische Verarbeitung von austenitischem CrNi-Stahl 7 2.2.2 Schweißnahtunregelmäßigkeit: Anlauffarben 12 2.3 Prozess- und Wurzelschutzgase 17 2.3.1 Prozessgase 18 2.3.2 Wurzelschutzgase 21 2.4 Messung von Sauerstoff und Feuchte bei schweißtechnischen Anwendungen 23 3 Präzisierung der Aufgabenstellung 28 4 Analyse von Baustellenbedingungen und Maßnahmen auf Winterbaustellen 29 4.1 Beschreibung der Bedingungen 29 4.2 Beschreibung der Unregelmäßigkeiten 31 4.3 Bewertung der etablierten Maßnahmen 33 5 Versuchsplanung und Durchführung 35 5.1 Experimentelle Randbedingungen 35 5.1.1 Geräte, Messmittel und Software 35 5.1.2 Versuchswerkstoffe und Materialien 42 5.1.3 Schweißparameter 43 5.1.4 Auswertungsmethoden 44 5.2 Einfluss der Feuchte in Wurzelschutzgasen 47 5.2.1 Schweißversuche bei konstanten und wechselnden Temperaturen 47 5.2.2 Versuche zur Feuchteansammlung im Rohr 49 5.2.3 Versuch zur Bildung von Anlauffarben bei unterschiedlichen Feuchtekonzentrationen im Wurzelschutzgas 51 5.3 Einfluss der Prozessgaszusammensetzung für die Gasgemische Ar, Ar/He, Ar/He/H2 53 6 Auswertung der Versuchsergebnisse und Schlussfolgerungen 56 6.1 Anlauffarben auf Winterbaustellen 56 6.1.1 Einfluss der Außentemperatur auf den Schweißprozess 56 6.1.2 Einfluss von Feuchteansammlungen in Rohren 61 6.1.3 Einfluss von unterschiedlichen Feuchtekonzentrationen im Wurzelschutzgas 63 6.1.4 Schlussfolgerungen für die Anwendung in der Praxis 68 6.2 Einfluss der Prozessgaszusammensetzung beim WIG-Orbitalschweißen 74 6.2.1 Versuchsauswertung 74 6.2.2 Anwendung des Mischgases Ar/He/H2 in der Praxis 80 7 Zusammenfassung und Ausblick 81 8 Quellenverzeichnis 82 9 Verzeichnis der Abbildungen und Tabellen 87 10 Anlagenverzeichnis 92

碩士
淡江大學
水資源及環境工程學系碩士班
101
In Taiwan, the quantity of waste glass recycling has increased over years. Current recyclable technology can effectively achieve the purpose of the waste glass recycling. Recycling is also the best way to manage municipal solid waste incinerator (MSWI) fly ash. However, the whole environmental load affected by the treatment process need to be consider, which can avoid to generate more environmental problems. Thus, if the Life Cycle Assessment(LCA) could be introduced at the initial stage of research and with full-scale simulation, we might have a better sense of direction and could improve the technique of the fly ash recycling that can reduce the environmental impact. This study used LCA to simulate the effect of recycling process of the MSWI fly ash and analyzed the environmental impact by Gabi of Life Cycle Assessment Software. This recycling technique of the MSWI fly ash with waste glass to manufacture humidity-controlling ceramic material can provide improving solutions accordingly. Waste glass, kaolinite and fly ash are the porous material and foaming agent, which can be synthesized by sintering technology to produce humidity-controlling ceramic material. The results of experiment indicate that there are two composition ratios can meet the standard of Japan humidity-controlling ceramic material specification and which would conform to CNS3299-4 standard. These ratios are 60% waste glass powder, 20% kaolinite and 20% fly ash (GKF-622); and 60% waste glass powder, 30% kaolinite, 10% fly ash (GKF-631). By using to the two ratios, this study accesses their lifecycles respectively. LCA used Eco-Indicator 99 index of Gabi5 to access the impact of human health, ecosystem and resources. The result of the LCA shows that the best ratio of GKF is GKF-631. The main environmental impact for producing 1 Kg of humidity-controlling ceramic material is 5.65Pt of resource consumption. The minor environmental impact is 2.13E-01Pt of human health. The minimal environmental impact is 1.51E-02 Pt of ecosystem quality. The order of environment impact in each process is as following: sintering process > water extraction process of MSWI fly ash > adjusting process > waste glass powdering process > molding process.

Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka comprises of six 18V 46 Wartsila turbocharged air cooled engines. Fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days. This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity. In this study the effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. This is to investigate the cause of efficiency variation and why and how it happens. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. For all the tests and analysis DG 02 at approximately Rhs: 55,000 was selected to conduct the measurements as 48,000 rhs major overhaul was completed recently. All the components in the fuel system such as pumping elements and injectors are in good condition. The cylinder head, liner and piston overhaul was also have been carried out. The experiments were planned so the lots other factors are not affecting the combustion efficiency during the process to isolate the ambient conditions. The experiments were also carried out during day and night times on the same day to minimize other factors such as fuel quality affecting the equations. Always the LHV of the incoming fuel was obtained for calculations to avoid further mistakes. The results are elaborated along with findings from the past studies in the Literature review. It was confirmed the fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the loss in the flue gas reduces in night time comparatively to the day time. At Heladhanavi temperature and humidity in charged air behaves in completely opposite manner in day and night times. During day time temperature is high while humidity is low. For the night time case its vise versa. Finally it can be concluded that under the prevailing ambient conditions at the Heladhanavi Power Plant, Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity in the combustion process for the Wartsila 18 V 46 diesel engines, as a result the efficiency improves during the night time comparatively to the day time. Therefore, proper cleaning and maintaining of the charge air coolers are the most important factor to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value. Therefore to attain the best electrical efficiency and the fuel consumption for a certain fuel batch.

Presentation was conducted online.

Yes
Objectives  In this work we investigated the residual organic solvent content and physicochemical properties of spray-dried chlorothiazide sodium (CTZNa) and potassium (CTZK) salts. Methods  The powders were characterised by thermal, X-ray diffraction, infrared and dynamic vapour sorption (DVS) analyses. Solvent levels were investigated by Karl–Fischer titration and gas chromatography. Key findings  Spray-drying from water, methanol (MeOH) and mixes of MeOH and butyl acetate (BA) resulted in amorphous microparticles. The glass transition temperatures of CTZNa and CTZK were ∼192 and ∼159°C, respectively. These materials retained their amorphous nature when stored at 25°C in dry conditions for at least 6 months with no chemical decomposition observed. DVS determined the critical relative humidity of recrystallisation of CTZNa and CTZK to be 57% RH and 58% RH, respectively. The inlet temperature dependant oxidation of MeOH to formaldehyde was observed; the formaldehyde was seen to deposit within the amorphous matrix of spray-dried product. Spray-drying in the open blowing mode coupled with secondary drying resulted in a three-fold reduction in residual BA (below pharmacopoeial permitted daily exposure limit) compared to spray-drying in the closed mode. Conclusions  Experiments showed that recirculation of recovered drying gas increases the risk of deposition of residual solvents in the spray-dried product.
The Irish Research Council for Science and Engineering Technology (IRCSET), the Solid State Pharmaceutical Cluster (SSPC), supported by Science Foundation Ireland under grant number (07/SRC/B1158) and the Irish Drug Delivery Research Network, a Strategic Research Cluster grant (07/SRC/B1154) under the National Development Plan co-funded by EU Structural Funds and Science Foundation Ireland.

Dissertação de mestrado integrado em Engenharia Mecânica
O objetivo geral desta dissertação passa pela melhoria do processo de humidificação de placas de hóstia. As placas de hóstia têm o formato retangular e são resultado da cozedura da massa que constitui as hóstias. Inicialmente estudou-se o processo produtivo de hóstias, no qual se enquadra o processo de humidificação, de forma a compreender todas as etapas necessárias à produção de hóstias. Este estudo permitiu ainda perceber a importância da humidificação no processo produtivo de hóstias. Com o objetivo de conhecer as soluções já existentes, elaborou-se um estudo de mercado. Posteriormente estudou-se o material das placas de hóstia, de forma a compreender o nível de humidificação ideal. Fez-se ainda um trabalho experimental que permitiu perceber a temperatura e humidade relativa, ideais, para que o processo seja o mais rápido possível. De seguida foram elaborados diversos ensaios à câmara de humidificação 1, com o objetivo de entender a razão pela qual o processo de humidificação utilizado não permite uma cadência suficiente para dar resposta à etapa de corte. Conhecidos os pontos fracos da câmara de humidificação 1, foram propostas melhorias para promover um processo de humidificação mais eficiente. Com o propósito de promover o projeto de um novo equipamento de humidificação, realizou-se um projeto conceptual na procura de soluções alternativas que consigam responder aos objetivos iniciais do projeto. O passo seguinte passou pela execução do projeto detalhado do equipamento, onde foram selecionados os componentes necessários para o correto funcionamento da máquina projetada. Por fim, realizou-se o projeto de automação do equipamento, permitindo um controlo automático do funcionamento do mesmo.
The general objective of this dissertation is to improve the host plates humidification process. The host plates are rectangular in shape and are the result of cooking the dough that forms the host. Initially it was studied the productive process of hosts, in which fits the process of humidification, in order to understand all the necessary steps to produce hosts. This study also allowed to understand the importance of humidification in the hosts production process. In order to know the existing solutions, it was conducted a market study. After that, it was studied the material of the host plates in order to understand the ideal level of humidification. Also, it has been done an experimental work to make it possible to understand the ideal temperature and relative humidity to make the process as fast as possible. Following, several tests were made to the humidification chamber 1, intending to understand why the used humidification process does not allow enough cadence to respond to the cutting station. Knowing the weaknesses of the humidification chamber 1, improvements were proposed to promote a more efficient humidification process. In order to promote the design of a new humidification equipment, it was carried out a conceptual design in search for alternative solutions that could meet the initial objectives of the project. The next step was the execution of the detailed design of the equipment, where the necessary components for the correct operation of the designed machine were selected. Finally, it was carried out the automation design of the equipment, allowing an automatic control of its operation.