Abstract The target in this thesis was to study selected special measurements in a basic oxygen furnace (BOF) and develop a model to predict the steel temperature at the end of the oxygen blow. Furthermore, the work aimed at increasing knowledge on measurements and phenomena in the converter and in this way improve the possibility of more efficient monitoring and control of the process. Special measurements were investigated to obtain more knowledge about their usability in running the converter process. Analysing the measurement results also led to new process knowledge. The usage of a Radio Wave Interferometer (RWI) was seen as beneficial as it makes it possible to see the rising trend of the liquid surface level in advance and to perform some corrective actions to avoid excessive foaming and possible splashing out from the converter. Acoustic measurement could also detect trends in advance, but it was found to be sensitive to disturbing noise from the surroundings. Splashing measurement gives information about the current state of the slag but not advance information. Nevertheless, the measurements revealed several factors that usually increase splashing. It would be best to use the knowledge from two different measurements, for example RWI and splashing measurement, to predict increasing splashing, which causes significant iron losses. The development of the models for end temperature prediction and additional materials provided a lot of knowledge about the factors affecting the temperature. Factors that were used in grouping were the BOF number, heat size and end carbon content. However, there were many heats that did not satisfy the target. Furthermore, there is a need for additional research into temperature progress and its control in BOF. It would also be useful to study the effect of additional materials more systematically. There are other factors, such as the oxygen flow rate and lance height, which affect the temperature that are not included in the models. Some of the factors are measurable and some are not. There is still a need for more research in this area. This work strengthens the impression that the converter process is a complex one. It was noticed; as always in process development, that continuous monitoring and efforts are required to observe the changes in process conditions, raw materials or running practices. Otherwise, the benefit of the improvements and models will be lessened. However, it would be possible to set acknowledged routines and warnings into the improved monitoring system to help the operators notice the need for system tuning. A monitoring system would provide financial benefits in terms of having fewer reblowings, better yield and better quality of final product. Savings in raw materials can also be attained as the controllability of the process becomes better. As the monitoring system contains a database of guidelines, it would form a good basis for new employees to become familiar with the process and thus facilitate their training. / Tiivistelmä Tämän opinnäytteen tarkoitus oli tutkia teräskonvertterin valittuja erikoismittauksia ja kehittää malli ennustamaan teräksen lämpötilaa happipuhalluksen lopussa. Työn tarkoituksena oli lisätä tietämystä mittauksista ja ilmiöistä konvertterissa ja tällä tapaa lisätä mahdollisuuksia prosessin tehokkaampaan monitorointiin ja ohjaukseen. Erikoismittauksia tutkittiin lisätietämyksen saamiseksi niiden käytettävyydestä konvertteriprosessin ajossa. Mittausten analysointi tuotti myös uutta prosessitietämystä. Radioaaltointerferometrin (RWI) käyttö koettiin hyödylliseksi, koska on mahdollista havaita kuonan pinnankorkeuden nousu ennakkoon ja suorittaa joitakin korjaavia toimenpiteitä liiallisen kuohumisen ja lopulta roiskumisen estämiseksi ulos konvertterista. Äänimittaus voi myös havaita trendin ennakkoon, mutta huomattiin sen olevan herkkä ympäristön häiriöäänille. Roiskemittaus antaa tietoa kuonan sen hetkisestä tilasta, mutta ei ennakkoon. Mittaukset toivat kuitenkin esiin useita tekijöitä, jotka yleensä lisäävät roiskumista. Olisi parasta käyttää kahden eri mittauksen tietoa, RWI ja roiskemittaus, ennustettaessa lisääntyvää roiskumista, joka aiheuttaa huomattavia rautahäviöitä. Loppulämpötilan ennustamiseen kehitetyn mallin ja lisäainemallin kehittäminen antoi paljon tietoa tekijöistä, jotka vaikuttavat lämpötilaan. Tekijät, joita käytettiin ryhmittelyssä, olivat konvertterinumero, panoskoko ja loppuhiilipitoisuus. Mallin soveltamisesta huolimatta jäi edelleen useita sulatuksia, jotka eivät osuneet tavoitteeseen. On edelleen tarve teräskonvertterin lämpötilakäyttäytymisen ja sen hallinnan lisätutkimukselle konvertterissa. Myös lisäaineiden vaikutusta lämpötilaan olisi hyödyllistä tutkia systemaattisemmin. On edelleen muita tekijöitä, esimerkiksi hapen virtausnopeus ja lanssin korkeus, jotka vaikuttavat lämpötilaan, mutta jotka eivät ole mukana malleissa. Osa näistä tekijöistä on mitattavia suureita ja osa ei. Lisätutkimukselle on edelleen tilaa tällä alueella. Tämä työ vahvistaa edelleen käsitystä, että konvertteriprosessi on monimutkainen. Huomattiin, kuten aina prosessikehityksessä, että jatkuvaa kehitystyötä pitää tehdä prosessiolosuhteiden, raaka-aineiden ja ajopraktiikoiden muutosten huomaamiseksi. Muuten parannusten ja mallien antama hyöty heikkenee. Monitorointijärjestelmään olisi mahdollista kehittää rutiineja ja varoituksia operaattorien avuksi, jotta he huomaisivat järjestelmävirityksen tarpeen. Monitorointijärjestelmä toisi taloudellista hyötyä, mm. lisäpuhallusten vähentymisen, lopputuotteen paremman saannon ja laadun muodossa. Raaka-ainesäästöjä voidaan saavuttaa prosessin ohjattavuuden parantuessa. Monitorointijärjestelmän sisältäessä sääntötietokannan, se luo hyvän pohjan uusille työntekijöille tutustua prosessiin ja näin heidän koulutuksensa onnistuisi helpommin.

Since decades, drop impact has been a popular topic of investigation for the importance that such a phenomenology has in many different application domains.<p><p>So far, the effect of micro-particles on the drop impact morphology has been studied for a limited number of configurations and often modelled as a change in the viscosity of the carrier fluid. However, this approach has been found sometimes questionable. The aim of the thesis is to better understand the phenomenology associated with particle-laden drop impact such as the distribution of particles in splats and to extend the number of experimental configurations for particle-laden drop impact to occur.<p><p>The impact of millimetre-size particle-laden drops was investigated for hydrophilic and hydrophobic substrates. The drops were dispersions of water and round, spherical and nearly iso-dense hydrophobic particles with diameters around 200 µm and 500 µm. The substrates were transparent glass and polycarbonate plates. The impact was studied by side, bottom and angle view images in the range 148≤We≤744 and 7092≤Re≤16368.<p><p>The particles were found to suppress the appearance of singular jetting and drop partial rebound, and also cause early splashing, receding break-up and rupture. The occurrences of these phenomena depend on the impact velocity, particles’ diameter and volume fraction. The drops with 200 µm particles spread in two phases: fast and slow, caused by inertial and capillary forces, respectively. Also, the increase of volume fraction of 200 µm particle leads to a linear decrease of the maximum spreading factor caused by the inertia force on the hydrophilic and hydrophobic substrates. The comparison of our data and the existing ones for splashing led to the formulation of а new splashing criterion for particle-laden drops. The novel criterion improves upon current models in predicting the splashing threshold by introducing effect of particle volume fraction and particle wettability. The analysis of particle distribution showed that 200 µm particles formed atypical distributions in splats after the impact in contrast to 500 µm particles with random pattern. The 200 µm particles formed rings/disks and a crown-like structure on hydrophilic and hydrophobic substrates, respectively. These patterns were described by correlations.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Drop impact is a canonical problem in fluid mechanics, with numerous applications in industrial as well as natural phenomena. The extremely simple initial configuration of the experiment can produce a very large variety of fast and complex dynamics. Scientific progress was made in parallel with major improvements in imaging and computational technologies. Most recently, high-speed imaging video cameras have opened the exploration of new phenomena occurring at the micro-second scale, and parallel computing allowed realistic direct numerical simulations of drop impacts. We combine these tools to bring a new understanding of two fundamental aspects of drop impacts: splashing and air entrapment. The early dynamics of a drop impacting on a liquid pool at high velocity produces an ejecta sheet, emerging horizontally in the neck between the drop and the pool. We show how the interaction of this thin liquid sheet with the air, the drop or the pool, can produce micro-droplets and bubble rings. Then we detail how the breakup of the air film stretched between the drop and the pool for lower impact velocities can produce a myriad of micro-bubbles.

本文的意圖並不在於探討西雙版納傣族潑水節狂歡的景象，而是將焦點放在傣族潑水節與水文化的關係上。“水”是西雙版納傣族的精神標誌，所以了解傣族文化之前，就必須先認識水文化，然後再來研究傣族潑水節的形成，以及潑水節從過去到現在的轉變，甚麼才是潑水節真正的文化意涵? 因此,本論文從西雙版納傣族潑水節文化意涵之研究著手, 探討水與傣族文化之間的關聯，與其在當代的存在價值, 這將是本論文研究的方向. 本文所包括的基本內容有： 第一章 人文與自然環境: 對傣族的歷史與天然環境、生活型態、宗教信仰和風俗 習慣等方面的特徵進行探討。 第二章 潑水節的探索: 結合筆者及國內外學者的研究成果和大量的相關歷史文獻資料，探討傣族的水文化和潑水節的形成，所反映出來的標識和風格特 徵，將在此章做說明 第三章 文化現象和定位: 此章介紹傣曆新年、文化現象的轉換和禁忌。 釐清大眾對西雙版納傣族潑水節的錯誤認知，並且訪談多位對傣文化相關研究的傑出專家學者、及2007年潑水節主辦單位，進行調查實錄及訪談。探討水文化和潑水節之間的因果關係、及節日中舉辦的各種活動之文化意涵進行探討。 第四章 潑水節的分析: 本章針對潑水節的內在以及外在意涵作分析。內在意涵包 括地方風俗、民族宗教和社會功能等方面；外在意涵則包括潑水節的特色、文化保護和傳承、以及其在當代的價值分別做微觀與宏觀的系統分析。 結論: 透過本文研究的發現並建議未來的研究方向 / This study doesn’t attempt to discuss the boisterous atmosphere of the Dai’s Water Splashing Festival(W.S.F.) in Xishangbanna(XSBN), but focuses on the relationship with the W.S.F and the water culture. Water is the spiritual symbol of the Dai people in XSBN. So before understanding the Dai’s culture, we must first recognize the influence of water culture on the Dai ethnic minority. Then we will examine the transformation of the W.S.F. from past to present, what is the real significance of the W.S.F.? And finally how does the W.S.F. reflect the external influence on the contemporary values? According to this study, it will be divided into 5 parts to discuss: 1. Humanity and the natural environment: The first chapter describes Dai’s history and geography, introduces the Dai’s lifestyle, and shows the Dai’s religious beliefs and customs. 2. Exploring the Dai Water Splashing Festival: The Dai’s water culture, and the formation of the W.S.F. will be explained in the second chapter. 3. Cultural phenomenon and orientation: It introduces the Dai New Year, and the transformation of culture phenomenon and taboos. 4. Analysis of the Water Splashing Festival: The fourth chapter analysis and interpretation the internal significance of the W.S.F, including the local folkway, ethnic religion, and social function. And it also shows the external significance of the W.S.F, including the special characteristics, protection and fostering of tradition culture, and its contemporary values. 5. Conclusion: The final conclusion combines with the above chapters to summarize the study of W.S.F.