Dissertationen zum Thema „Break-up process“

The research of this thesis focuses on the study of sprays produced by twin fluid air-blast atomisers and the main objective is to study the liquid jet break-up mechanism and relate it to the downstream spray characteristics. Two different air-blast atomiser geometries are used; coaxial, where the liquid co-flows with the gas stream, and the liquid jet in a gaseous cross-flow. The thesis describes advanced and novel measurements to reveal the temporal and spatial development of the liquid flow and its interaction with the surrounding gas stream. Initially, the break-up process is studied by measuring the characteristics of the continuous liquid jet. Techniques such as electrical conductivity, high-speed shadowgraphy and optical connectivity were used to characterise the atomisation process. The latter is a novel laser-based technique used to illuminate internally the continuous liquid column by introducing a laser beam within the liquid nozzle, while a fluorescent dye in the liquid ensures that the whole volume of the liquid is visualised. The laser light propagates downstream while reflecting on the gas-liquid interface to be interrupted at the break-up position, where the light is scattered and diffuses widely. In the case of a jet in a cross-flow gas stream the fluorescent intensity images were recorded from two different angles to reveal the various features involved in the liquid jet structure. The study of the spatial and temporal characteristics of the instabilities and the developed surface waves on the liquid column can provide information on jet morphology and a better understanding of the physics that elicit the break-up phenomenon. For that purpose, Proper Orthogonal Decomposition (POD) is applied to reveal the various flow scales and elucidate the mechanism of transfer of momentum from the gas to the liquid flow. The most energetic modes are used to describe the jet interface dynamics that may well define the formation of the downstream droplet sizes. Interferometric Laser Imaging for Droplet Sizing (ILIDS) was also used for planar measurements of droplet sizes and velocities. ILIDS images the scattered light from droplets in an out-of-focus mode at different streamwise distances from the nozzle exit to obtain interference fringe patterns associated with each droplet. The spacing of each fringe pattern is proportional to the corresponding droplet diameter. Instantaneous droplet clustering is measured along with the primary atomisation process and the liquid jet break-up characteristics are correlated with the downstream droplet sizes. Several time delays are used between optical connectivity and ILIDS measurements to capture the various classes of droplet sizes that travel with different velocities from the break-up region to the downstream spray location. The small droplets travel faster and move with a velocity similar to the gas flow, in contrast to the larger droplets, which are conveyed to the size measuring region with a lower velocity and, therefore, higher time delays. A conditional correlation method was developed to reduce statistical uncertainties. Negative correlations were found between the break-up length of the liquid jet and downstream number of droplets, indicating that they are inversely proportional. The relation between the break-up length and droplet Arithmetic and Sauter Mean Diameters seems to be more complex since a sinusoidal relation was extracted. The estimated correlation coefficients varied with time delay and a repeatable trend was observed which exposed the coherent behaviour of the break-up process and its frequency, revealing that it is not a random phenomenon, but rather a multifaceted mechanism governed by physical laws.

A pilot scale study of the dynamics of the break-up of curved liquid jets is presented. This work is motivated by an industrial process called prilling which is used in the manufacture of pellets. In this process a sieve-like cylindrical can spins rapidly on its central vertical axis. Molten liquid is pumped into the top of the can and flows from the holes in the form of curved liquid jets. Experiments are described which were carried out on a pilot scale rig. Some differences between the break-up modes observed in this study and previous work using a small laboratory scale rig are discussed. Previous theories describing break-up mechanisms of curved liquid jets were extended to include viscosity and gravity. Break-up lengths and drop sizes were obtained theoretically and compared with experimental results. Experiments were carried out using insonification, a process where sound waves are fired at the jet to control satellite drop formation. Three different frequencies of wave were used, 10, 100 and 200 Hz at four different rotation rates. It was observed that insonification was successful at eliminating satellite drops at low rotation rates and when frequencies of 100 or 200 Hz were used. Insonification was included in the theory. The theory predicted that insonification eliminated satellite drops for a large range of frequencies in the experimental regimes for sufficiently large acoustic volume. The theory also predicted that satellite drops were eliminated in parameter regimes outside the experimental regimes. The trajectory of the jet was allowed to become unsteady, in a rotating frame of reference. Simulations were carried out in inviscid and viscous regimes.

El proceso de atomización desde una vena o lámina líquida hasta multitud de gotas dispersas en un medio gaseoso ha sido un fenómeno de interés desde hace varias décadas, especialmente en el campo de los motores de combustión interna alternativos. Multitud de estudios experimentales han sido publicados al respecto, pues una buena mezcla de aire-combustible asegura una evaporación y combustión mucho más eficientes, aumentando la potencia del motor y reduciendo la cantidad de contaminantes emitidos. Con el auge de las técnicas computacionales, muchos modelos han sido desarrollados para estudiar este proceso de atomización y mezcla. Uno de los últimos modelos que han aparecido es el llamado ELSA (Eulerian-Lagrangian Spray Atomization), que utiliza un modelo Euleriano para la parte densa del chorro y cambia a un modelo Lagrangiano cuando la concentración de líquido es suficientemente pequeña, aprovechando de esta manera las ventajas de ambos. En el presente trabajo se ha desarrollado un modelo puramente Euleriano para estudiar la influencia de la geometría interna de la tobera de inyección en el proceso de atomización y mezcla. Se ha estudiado únicamente el proceso de inyección diésel. Este modelo permite resolver en un único dominio el flujo interno y el externo, evitando así las comunes simplificaciones y limitaciones de la interpolación entre ambos dominios resueltos por separado. Los resultados actuales son prometedores, el modelo predice con un error aceptable la penetración del chorro, el flujo másico y de cantidad de movimiento, los perfiles de velocidad y concentración, así como otros parámetros característicos del chorro.
Martí Gómez-Aldaraví, P. (2014). DEVELOPMENT OF A COMPUTATIONAL MODEL FOR A SIMULTANEOUS SIMULATION OF INTERNAL FLOW AND SPRAY BREAK-UP OF THE DIESEL INJECTION PROCESS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43719
TESIS
Premiado

Former studies show that the break-up from prostitution can be seen as a process with several stages which the person has to go through and that there are several factors which can affect the break-up. The aim of this study is to create an understanding for and illustrate how a break-up from prostitution can look like. We have interviewed three ex-prostitutes about their own break-up and three social workers who work with helping individuals to exit prostitution. We have analyzed the material through the theory of exit process by Helen Fuch Ebaugh (1988) and through former studies. All the ex-prostitutes and the social workers in our study described the break-up from prostitution as a process. All our respondents agreed on that there are several different factors affecting a break-up from prostitution, whereof close relationships and the own motivation to make a change are the most significant ones. Formal support from professionals is also considered having an impact on the exit process as well as during the period after the break-up. In summary, the break-up process from prostitution is very complex, can be emotionally exhausting and may vary to a great extent between individuals.

In this study, the topic of men’s violence against women has been highlighted. Men’s violence against women is a societal problem that occurs in various social groups, ages and cultures. The study conducts semi-structured interviews with six social workers to examine their experiences working with abused women with foreign backgrounds. The collected data were analyzed through thematic analysis method based on: the normalization process, empowerment and break-up process. The study showed that some of the main factors that made it difficult for women were children, emotional ties, financial and housing dependencies. This study also confirmed previous studies which showed that women with a foreign background are particularly vulnerable and thus find it more difficult to break up a relationship due to societal norms, language difficulties, social networks and because of their ignorance of society. This study also shows that the interviewed social workers found that motivation and support given to violated women in various processes made the break-up process easier for these women. However, the social workers encountered some difficulties working with women with a foreign background, such as communication difficulties.

Syftet med studien var att identifiera de faktorer i kvinnors utsatthet för våld av män i nära relationer som påverkar deras val och möjlighet att stanna i alternativt lämna en våldsam parrelation samt vilken inverkan och påverkan det sociala nätverket har på kvinnors beslut att stanna i alternativt lämna relationen. Genom kvalitativ innehållsanalys av fyra självbiografier skrivna av tidigare våldsutsatta kvinnor sammanställdes resultat, som tematiserades och analyserades med hjälp av teorierna och begreppen normaliseringsprocess, traumatisk bindning och uppbrottsprocess tillsammans med tidigare forskning. Resultatet visade att anledningar till att en våldsutsatt kvinna stannar i en våldsam parrelation är starka känslomässiga band, normalisering av våldet, beroende, psykisk nedbrytning, internalisering, rädsla samt hopp om förändring. Vad som gör att en våldsutsatt kvinna lämnar en våldsam parrelation är insikten om att det skulle vara ohållbart att stanna av olika anledningar samt rädsla för sitt eget eller annans liv. Uppbrottsprocessen kan förklaras likt en process i flera steg. Omgivningens stöd visade sig också ha stor betydelse i kvinnans val och möjlighet att kunna lämna relationen, dock är beslutet att lämna relationen tvunget att komma från kvinnan själv. Slutsatsen var därmed att kvinnor som utsätts för våld av män i nära relationer är en mycket utsatt grupp i samhället, relationen till männen är ofta komplex. För att bryta kvinnors isolering, som följd av våldsutsattheten, krävs insatser från omgivningen samt förändring på samhällelig nivå.
The purpose of the study was to identify the factors in women's exposure to violence by men in intimate relationships that affect their choice and ability to stay in or leave a violent relationship and what impact the social network has on women's decision to stay in or leave the relationship. Through qualitative content analysis of four autobiographies written by previously abused women, results were compiled, thematized and analysed using theories and concepts such as normalization process, traumatic bonding, and break-up process together with previous research. The results showed that reasons why an abused woman stays in a violent relationship are strong emotional bonds, normalization of violence, addiction, being mentally break down, internalization, fear and hope for change. What causes an abused woman to leave a violent relationship has turned out to be the realization that it would be unsustainable to stay for various reasons as well as fear for her own or someone else's life. The breaking process can be explained as a process in several steps. The social network had a great importance in the woman's choice and opportunity to be able to leave the relationship, however, the decision to leave had to come from the woman herself. The conclusion was thus that women who are exposed by men in intimate partner violence are a very vulnerable group in society, the relationship is often complex. Breaking women's isolation, as a result of domestic violence, requires efforts from the social network and change at the societal level.

This paper presents the feasibility study of setting up the new potting tray production line based on the two alternatives: partly outsource a process in the production line or wholly make all processes in-house. Both the qualitative and quantitative approaches have been exploited to analyze and compare between the make or buy decision. Also the nature of business, particularly SMEs, in Thailand has been presented, in which it has certain characteristics that influence the business doing and decision, especially to the supply chain management. The literature relating to the forecasting techniques, outsourcing decision framework, inventory management, and investment analysis have been reviewed and applied with the empirical findings. As this production line has not yet been in place, monthly sales volumes are forecasted within the five years time frame. Based on the forecasted sales volume, simulations are implemented to distribute the probability and project a certain demand required for each month. The projected demand is used as a baseline to determine required safety stock of materials, inventory cost, time between production runs and resources utilization for each option. Finally, in the quantitative analysis, the five years forecasted sales volume is used as a framework and several decision making-techniques such as break-even analysis, cash flow and decision trees are employed to come up with the results in financial aspects.

Die kosmische Nukleosynthese 35 protonenreicher stabiler Nuklide zwischen Selen und Blei kann nicht durch Neutroneneinfangprozesse erklärt werden. Es wird angenommen, dass diese Kerne in explosiven Szenarien, wie Supernova-Explosionen durch Protoneneinfang oder Photodesintegrationsprozesse, erzeugt werden, jedoch sind die solaren Häufigkeiten dieser sogenannten p-Kerne noch nicht verstanden. Der p-Kern mit der größten Isotopenhäufigkeit, 92Mo, wird in Nukleosynthese-Netzwerkrechnungen deutlich unterproduziert. Eine mögliche Ursache könnten unpräzise Reaktionswirkungsquerschnitte sein, da die meisten Wirkungsquerschnitte nur aus Modellrechnungen bekannt sind. Daher war es naheliegend, die Photodesintegrationswirkungsquerschnitte von 92Mo mit der Methode der Photoaktivierung an der Strahlungsquelle ELBE im Forschungszentrum Dresden-Rossendorf zu überprüfen. Durch die hohe Intensität der Bremsstrahlung von bis zu 10^9 MeV^-1cm^-2s^-1 im Energiebereich bis zu 20 MeV konnten im Rahmen dieser Arbeit erstmals nicht nur die (γ,n)-, sondern auch die (γ,p)-Reaktionen an 92Mo bei astrophysikalisch relevanten Energien untersucht werden. Durch die Messungen an zwei Bestrahlungsplätzen konnten systematische Unsicherheiten reduziert werden. Insbesondere wurde eine präzise Bestimmung der Photonenfluenz vorgenommen: Am Kernphysikmessplatz erfolgte die Bestimmung mittels Kernresonanzfluoreszenz an 11B. Im Elektronenstrahlfänger wurde die Photodesintegrationsreaktion 197Au(γ,n) zur Normierung der Photonenfluenz verwendet, nachdem sie zuvor am Kernphysikmessplatz überprüft wurde. Die Reaktion 92Mo(γ,n)91mMo, mit einer Halbwertszeit des Endkerns von 65 s, war dank einer Rohrpost zugänglich, mit der die Proben in weniger als 10 s von der Bestrahlungsstation zum Zerfallsmessplatz transportiert werden können. Die Messungen dieser Arbeit bestätigen im wesentlichen die Hauser-Feshbach-Modellrechnungen bezüglich der Photodesintegrationsreaktionen (γ,n) und (γ,p). Die Unterproduktion der Mo- und Ru-Isotope ist daher nicht erklärbar durch ungenaue Wirkungsquerschnitte. Zur Nukleosynthese dieser Kerne müssen andere astrophysikalische Prozesse, z.B. neutrinoinduzierte Reaktionen beitragen. Die gemessenen Photoaktivierungsausbeuten haben eine hohe Empfindlichkeit auf die Photonenstärkefunktion. ÄAnderungen der Dipolriesenresonanzparameter wirken sich stärker auf berechnete Ausbeuten aus, als ÄAnderungen der Kernniveaudichte oder der Parameter des optischen Modells. Durch gleichzeitige Messung der Photodesintegration am Kern 100Mo konnten Unsicherheiten in der Normierung von Photoneutronenexperimentdaten aus der Positronenannihilation im Flug geklärt werden.

Das Thema der Arbeit ist experimentelle Bestimmung der Ausbeute durch Photoaktivierung von Mo-92 mittels Bremsstrahlung des supraleitenden Elektronenlinearbeschleuniger ELBE im Forschungszentrum Dresden-Rossendorf. Mo-92 ist der p-Kern mit der größten Isotopenhäufigkeit und wird in astrophysikalischen Netzwerkrechnungen deutlich unterproduziert. Untersucht wurde dabei insbesondere der (gamma,p)- und (gamma,n)-Kanal, wobei für letzteren wegen der Halbwertszeit des Endkerns (Isomer) von 65 s eine Rohrpost verwendet wurde. Die Aktivierung erfolgte an zwei verschiedenen Bestrahlungsplätzen. Am Kernphysikmessplatz konnte die Photonenfluenz absolut mittels Kernresonanzfluoreszenz an B-11 bestimmt werden. Im Elektronenstrahlfänger wurde die Photodesintegrationsreaktion Au-197(gamma,n) zur Normierung verwendet. Die Endpunktsenergie wurde über den Deuteronenaufbruch durch Messung der Protonenspektren mit Si-Detektoren bestimmt. Die Ergebnisse wurden mit der integralen Ausbeute mit Hauser-Feshbach-Modellrechnungen verglichen. Parasitär konnte auch die Ausbeute der Aktivierung des in natürlichem Mo enthaltenen Isotops Mo-100 untersucht und mit früheren Photoneutronenexperimenten verglichen werden.

碩士
國立臺灣大學
社會學研究所
96
Breaking up is formerly investigated by various approaches. Some researchers developed stage models to describe the process of breaking up. In those models, there is a dyad phase in which two partners interact. This research develops a framework with two dimensions in order to interpret the contents and rules in the process of breaking up. One dimension is the consistency of the receiving/sending role. This dimension address the issue that the one sending breaking up message may or may not be the one who initiate the breaking up process. The other dimension is the directness of breaking up actions, which can be either a direct proposal or an indirect refusal to interact. Therefore, there are four interaction types in this framework. We discuss the first three interaction types in this research. Furthermore, participants interact not only with their former romantic partners, but also with their social friends for suggestions and supports, while only few participants turn to their family members, teachers and the professionals. The second emphasis of this study is identity transformation. Identity transformation refers how two people in the relationship realized they are two separated individual, rather than a couple in a romantic relationship. As identity of relationship transform, the participants showed decreased self confidence. But after they walked through the darkness, they showed increased self-esteem. This research interviews 11 participants to collect their experiences in breaking up processes.

碩士
國立彰化師範大學
輔導與諮商學系所
104
This research goal is to understand the experiences and effect of being social supported in the process of accommodation for breaking-up in the relationship of romance of woman who were passively separated in the romantic breakup with Qualitative approach. The researcher use semi-structured depth interview method, collecting respondents’ connotations of experience, and integrate them with Scenario analysis and category Analysis. All 5 participants (2 college student, 3 graduate student) suffer passively separated in the romantic breakup in the recent 2 years, and percived themselves have gone through the process of accommodation for breaking-up in the relationship of romance. Four results are found: (1)effective social supports are listening, accompanying, doing breakup related(or unrelated) activity.(2) ineffective social supports are blaming heartbreaker, refuse the heartbreaker’s need of accompany, which make them more frustrated, (3)in the beginning of process of accommodation for breaking-up in the relationship of romance, the heartbreaker feels lonely, at the meantime, supporter’s listening and accompany is the most important; in the middle stage, heartbreaker’s emotion become smooth, activities which can distraction from loss(e.g., travel) is effective. Since that the heartbreaker is reformatting their self-concept, if the supporter argue that they are trapped in the emotion, the heartbreaker prone to perceived the discussion as blaming them, which is ineffective; in the later period, the heartbereaker start new life and growth, less support were needed, flexible supports is effective(e.g., responsing to catharsis, self growth discussion ); supporter failing to recognize and understand heartbreaker’s emotion is ineffective.(4) In the distinction of social support, the intimacy of the supporter and the heartbreaker influence the effectiveness of social support, close family and friends are the most effective, people who easy to get along with (face to face), make the heartbreaker feel safe are also effective. Conclusion: According to these result, researcher proposed some responses to the past researches of being the heartbreaker’s company. Possible future research directions and recommendations are also discussed.

碩士
國立成功大學
教育研究所
102
This study is qualitative research to explore and understand the early adults’ emotion and process of adaptation in the experience of break up. Research method is based on narrative research, using depth semi-structured interviews to collect data. Using purposive sampling between the ages of 18-30 years old, have had the experience of love, and unmarried adults, including students still in school, and the adults of the community. In this study, the following conclusions: (1) Explore the history of the development of love: The perception of love a big difference, from acquaintance to contact. (2)The experience of breaking up and emotion and process of adaptation: when must Face with breaking up ... through choice , emotions and feelings good and bad, “adaptation and recovery, influence and change. (3) Looking Ahead: self-growth and realize, in the future, when face with the promise of love.Overall, early adults’ emotion and process of adaptation in the experience of break up, so that they get a lot of really profound revelation and harvest. According to the research results and findings , the researcher propose some related to future researchers , counseling counselors, school educators ... and put forward proposals for the purpose of reference.

碩士
國立臺南大學
諮商與輔導學系碩士班
98
The main purpose of this research is to explore the self-transformation process of cohabitants who experienced development and break-up process in the close relationship. This study adopted a narrative approach and holistic-contend perspective to analyze the data. Three interviewees participated in this study. The findings of this research are as follows: 1.The integral influence of the individual self in the process of romantic experience from cohabitation depends on the original self-importance and relational interdependence of the individual self. 2.During the Cohabitation, the difference in the presumption of the intimacy, the reception of the sexual behavior and the evaluation from the other side, the conflict between individual and relational demand and the craving for family or marriage will have an impact on the individual self. First, the situation of the cohabitation triggers the individual for the craving for family or marriage, promoting the individual’s endeavor to manage the relationship. When the relationship advances as expected, it will promote the positive transformation of the individual self. Second, confronting the adaptation in the daily life and the different expectations, the cohabitants will reveal the conflict between the individual and the relational demand, resulting in the struggle of self-adjustment. Third, the difference in the presumption of the intimacy will influence the cohabitants’ satisfaction towards the relationship. The disappointment at the feeling may transform as self-frustration or self-repression to avoid the continuation of sentiment consuming. Fourth, the inclination towards sexual behavior during the period of cohabitation implies the change of the relationship, affecting the self-opinion of the individual. Male cohabitants show the sense of control over the body and the relationship through the dominance of sexual behavior, while female shaping self body image in the process. 3.Cohabitation life is under the influence of social gender stereotype, which becomes a potential factor of the inner self-conflict for the individual. 4.Individual’s original craving for family is destroyed after the break-up from cohabitation. The unsolved inner self-conflict due to the cohabitation in the past will emerge from the mind again and again, presenting the status of self-lost and frustration. The key to self-transformation lies in the self awareness of the role in the relationship so as to begin the self-coordinating process, integrate the inner conflict between the individual self and the relational self resulting from the process of cohabitation, and develop a balanced status of a new self. Finally, suggestions for further research, cohabitant, and counselor will be proposed based on the result of the research.

Das Thema der Arbeit ist experimentelle Bestimmung der Ausbeute durch Photoaktivierung von Mo-92 mittels Bremsstrahlung des supraleitenden Elektronenlinearbeschleuniger ELBE im Forschungszentrum Dresden-Rossendorf. Mo-92 ist der p-Kern mit der größten Isotopenhäufigkeit und wird in astrophysikalischen Netzwerkrechnungen deutlich unterproduziert. Untersucht wurde dabei insbesondere der (gamma,p)- und (gamma,n)-Kanal, wobei für letzteren wegen der Halbwertszeit des Endkerns (Isomer) von 65 s eine Rohrpost verwendet wurde. Die Aktivierung erfolgte an zwei verschiedenen Bestrahlungsplätzen. Am Kernphysikmessplatz konnte die Photonenfluenz absolut mittels Kernresonanzfluoreszenz an B-11 bestimmt werden. Im Elektronenstrahlfänger wurde die Photodesintegrationsreaktion Au-197(gamma,n) zur Normierung verwendet. Die Endpunktsenergie wurde über den Deuteronenaufbruch durch Messung der Protonenspektren mit Si-Detektoren bestimmt. Die Ergebnisse wurden mit der integralen Ausbeute mit Hauser-Feshbach-Modellrechnungen verglichen. Parasitär konnte auch die Ausbeute der Aktivierung des in natürlichem Mo enthaltenen Isotops Mo-100 untersucht und mit früheren Photoneutronenexperimenten verglichen werden.