647 research outputs found
University of New Mexico Pipe Organ, Albuquerque
No full textIn the "Urban Places" series. A large pipe organ photographed from above on the campus of the University of New Mexico
Rotating heat pipe assisted annealing
No full textSteel is an indispensable material for the sustainable maintenance and progress of modern civilization. Its versatility in terms of mechanical and thermal characteristics, corrosion resistance, raw material availability, energy consumption and recyclability provides a clear advantage in a fast-changing technological landscape. In order to adapt to the changing needs, steel production methods have been evolving and improving over time. One such improvement opportunity in terms of energy efficient production is the ”heat pipe assisted annealing” concept. The cold rolling of steel is a process where the steel strip is cold-worked by means of rolls to achieve thickness reduction and better uniformity. This results in the strain hardening of steel. To reduce the hardness of steel and to render it more workable, it is thermally treated by heating it to a target soaking temperature and then cooling it down. This process is called annealing and it is an energy intensive process. Conventionally, heating is achieved with natural gas fired furnaces, whereas cooling is done using convective gas cooling. With this setting, the thermal energy extracted from the steel strip during the cooling stage is not used in any way. Moreover, none of the energy that is introduced during the heating stage is retained in the final product.An alternative technology for the annealing of steel was developed at Tata Steel IJmuiden R&D with the objective of recovering and using some of the heat removed during the cooling stage and thus, achieving more energy efficient annealing. With this technology called heat pipe assisted annealing, the cooling strip is thermally linked to the heating strip with multiple rotating heat pipes. In this way, each heat pipe transfers a certain amount of heat from the cooling strip to the heating strip. Only final heating and cooling of the steel strip is carried out in a conventional way. This concept is applicable to relatively low temperature (sub-critical) annealing where the cooling rate is not crucial. Therefore, packaging steel is a good candidate for the application of this technology.A rotating heat pipe is a highly efficient heat transfer device which is a wickless hollow cylindrical vessel rotating around its symmetric axis and containing a fixed amount of working fluid. The working fluid acts as a thermal energy carrier, transporting heat from one end of the heat pipe to the other. This basically occurs in four steps: (i) heat added to the evaporator part of the heat pipe causes the evaporation of the liquid, (ii) vapor travels to the condenser end of the heat pipe due to pressure difference, (iii) vapor condenses in the condenser section where heat is removed from the heat pipe, (iv) liquid returns to the evaporator with the help of the static pressure head and the centrifugal force induced by rotation. The heat pipe assisted annealing concept has been patented and subsequently further studied by Tata Steel Europe R&D. A water-filled rotating heat pipe test rig integrated with steel strips provided the bulk of the prior work. This test rig served as the proof-of-principle installation and it showed that heat can be transported from a hot strip to a cold one with a rotating heat pipe. In this context, several gaps have been identified to further acquire the knowledge on the system components, the concept performance and feasibility.This thesis focuses on four main aspects of the fundamentals and the feasibility of the heat pipe assisted annealing concept: (i) contact heat transfer between the steel strip and the rotating heat pipe, (ii) computationally efficient modelling of the interior dynamics of a rotating heat pipe, (iii) applicable working fluids for the high temperature range, (iv) behavior of the heat pipe assisted annealing system as a whole. These aspects are studied through a thermal engineering perspective. The heat pipe assisted annealing concept relies on the effective transfer of heat from the strip to the rotating heat pipe and vice versa. Therefore, it is important to understand the underlying physics governing this heat transfer and to be able to predict the heat transfer rate for possible configurations. In this context, in Chapter 2 of this thesis, the contact heat transfer between a steel strip and a rotating heat pipe is investigated both experimentally and numerically. The numerical model is based on first principles. It finds the thickness and the pressure of the gas layer between the strip and the heat pipe and subsequently considers different heat transfer mechanisms. The experimental work was carried out on the proof of- principle test rig. The model is validated with the experimental results. The contact heat transfer coefficient in the uniform region varied between 4,000 to 20,000 W/(m2.K). It showed an increase in the contact heat transfer with decreasing strip velocity and increasing radial stress. For the considered cases, conduction through the gas layer was the dominant heat transfer mechanism. Additionally, a simplified expression has been developed for the calculation of contact heat transfer through multiple regression analysis. The modelling of a rotating heat pipe is a crucial step for the detailed study of the heat pipe assisted annealing technology. Although modelling of rotating heat pipes has been the subject of many studies in the literature, these models are not computationally efficient enough to allow for the simultaneous modelling of multiple heat pipes linked to each other with strips. On this ground, in Chapter 3, a novel computationally efficient engineering model describing the transient behavior of the heat pipe is developed. In this model, the liquid and the vapor cells are allowed to change size radially in order to allow for the tracking of the liquid / vapor interface without the need for fine meshing or re-meshing. The model is also adapted to capillary-driven heat pipes. The model is validated with experimental and numerical studies from the literature. The deviation is computed to be around 2% with the numerical and analytical studies and around 6% with the experimental study.The heat pipe assisted annealing concept requires the operation of heat pipes within a temperature range of 25 °C to 700 °C. In order to operate within this range, different working fluids need to be used for different temperature ranges due to constraints of vapor pressure, life time, performance and safety. These working fluids are studied in Chapter 4. First, a selection of the working fluids is made based on a literature review. This selection yielded water, Dowtherm A, phenanthrene and cesium. Then, a life time test has been carried out with thermosyphons to test the stability of phenanthrene. At the end of a 3 months long test at 460 °C, thermal decomposition of phenanthrene was observed. However, these tests should be repeated with better initial vacuum and at multiple temperatures. Finally, Dowtherm A has been used in a rotating heat pipe setup to test its applicability and performance. It has been shown that Dowtherm A is suitable to be used in a rotating heat pipe at the designated temperature range in terms of performance, provided that annular flow is avoided. With the knowledge gathered from the previous chapters of this thesis, a model of the heat pipe assisted annealing line has been developed in Chapter 5. The aim of this model is to quantify the energy efficiency advantage brought by the concept for different number of heat pipes and to understand the behavior of the system as a whole. The simulations were run for a fixed plant layout with varying number of heat pipes and an average wrap angle of 104°. The energy recoveries for the simulations run for a strip of 0.25 mm and a line speed of 6.133 m/s were 76.5%, 73.4%, 69.4% and 63.9% for a total number of 90, 75, 60 and 45 heat pipes, respectively. From the simulation results it follows that cesium heat pipes are more efficient than organic heat pipes. Finally, the simulation results showed that the thermal cycle requirements can be satisfied with this new technology.Large Scale Energy Storag
Top of Head with Glasses and Pipe
No full textIn the "Portraits" series. The back of someone's head with very short hair and glasses sitting backwards on the head
W gorsecie czy w surducie? Strój w dziewiętnastowiecznym dyskursie emancypacyjnym
No full textThe paper illustrates the relationship between women’s clothing and the processes of modernization in the 19th century Europe. The author focuses on the discourse of emancipation and women who, like the French writer George Sand and a group of her Polish followers, broke away from the traditional image of women and adopted masculine clothing. In Poland, the interpretation of Sand’s lifestyle, characterized by her preference for masculine clothing, posed a challenge to her first biographers, who associated the author of Indiana with Frederic Chopin. A woman in a frock coat with a cigar or pipe in her hand was seen by opponents of emancipation as a troublemaker seeking applause. She discredited not only herself, but also the idea of emancipation. Accusations of seeking attention and cheap sensation were accompanied by charges of a sexual-erotic nature: shamelessness, licentiousness, and moral decay. Eliza Orzeszkowa knew and appreciated Sand’s work. She herself avoided talking about her private life. In Kilka słów o kobietach (1870, A Few Words On Women), the essay which was fundamental to the further development of the emancipation movement in Poland. She criticized the troublemakers, bluestocking and lioness women, who reduced the idea of equality to behaviour that violated social norms. In her emancipation program, she advocated respect for the family and marriage, and moral and ethical standards.Artykuł ukazuje związek między strojem kobiecym a procesami modernizacyjnymi zachodzącymi w Europie w XIX wieku. Autorka koncentruje się na dyskursie emancypacyjnym i kobietach, które tak jak francuska pisarka George Sand i grono jej polskich naśladowczyń zrywały z tradycyjnym wizerunkiem kobiety i zakładały męskie stroje. W Polsce z interpretacją stylu życia Sand, noszącej męską garderobę, nie radzili sobie jej pierwsi biografowie, piszący o autorce Indiany w związku z Fryderykiem Chopinem. Kobieta w surducie, z cygarem lub fajką w ręku w ocenie przeciwników emancypacji była awanturnicą, szukającą poklasku. Kompromitowała nie tylko siebie, ale i ideę emancypacyjną. Do oskarżeń o szukanie atencji i taniej sensacji dochodziły zarzuty o podłożu seksualno-erotycznym: o bezwstydności, rozwiązłości, zgniliźnie moralnej. Eliza Orzeszkowa znała i ceniła twórczość Sand. Sama unikała mówienia o swoim życiu prywatnym. W Kilku słowach o kobietach (1870), rozprawie fundamentalnej dla dalszego rozwoju ruchu emancypacyjnego w Polsce, krytyce poddała awanturnice, sawantki i kobiety lwice, które ideę równouprawnienia sprowadzają do zachowań naruszających społeczne normy. W swoim programie emancypacyjnym opowiedziała się za poszanowaniem rodziny, małżeństwa i norm moralno-obyczajowych
Dynamic modeling of the heat pipe-assisted annealing line
No full textIn a conventional continuous annealing line, the energy supplied to steel strip during heating is not recovered while cooling it. Therefore, an alternative heat transfer technology for energy efficient continuous annealing of steel was developed. This technology enables reusing the heat extracted during cooling of the strip in the heating part of the process. This is achieved by thermally linking the cooling strip to the heating strip via multiple rotating heat pipes. In this context, the dynamic simulation of a full heat pipe assisted annealing line is performed. The dynamic simulation consists of the interaction of computational building blocks, each comprising of a rotating heat pipe and strip parts wrapped around the heat pipe. The simulations are run for different installation configurations and operational settings, with the heat pipe number varying between 50 and 100 and with varying strip line speed and dimensions. The heat pipes are sized to be 0.5 m in diameter and 3 m in length. The simulation results show that the equipment is capable of satisfying the thermal cycle requirements of annealing both at steady-state and during transition between steady-states following changes in boundary conditions. With this concept, energy savings of up to 70% are feasible.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Large Scale Energy StorageProcess and EnergyEnergy Technolog
Pipe uplift in liquefied sands: The case of induced earthquakes in the Groningen area
No full textThis study considers pipe uplift in liquefied sands in case full liquefaction occurs in the Groningen area. Due to the short vibration time, approximately 2 seconds, uplift is considered in fully liquefied sands without vibrations. The liquefaction time and resistance against uplift are determined by experiments. The resistance against uplift is determined for pipe diameters of 110mm, 160mm and 200mm.Geo-engineeringGeoscience & EngineeringCivil Engineering and Geoscience
Analysis and design of pipe ramming installations
No full textThis archived document is maintained by the Oregon State Library as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Title from PDF cover (viewed on June 5, 2015)."SPR-710."Includes bibliographical references (page 11).Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Design optimisation and commissioning of the Delft rotating heat pipe setup
No full textThe heat pipe assisted annealing project is a project in which Tata Steel, TU Delft and Drever International work together to develop a continuous annealing line with heat pipes. In an annealing line cold rolled steel is heated to 973 K and cooled down again to change the properties of the steel. In the heat pipe assisted annealing project the cooling line is thermally connected to the heating line via heat pipes. A heat pipe is a closed cylinder which is partly filled with a liquid. Heat pipes are very effective heat transfer devices, due to evaporation of the liquid at one side of the heat pipe and condensation of the vapour at the other side of the heat pipe. Due to rotation and a head, liquid will return to the evaporator side of the heat pipe. Applying heat pipes in a continuous annealing line could lead to energy savings up to 70%.The TU Delft rotating heat pipe setup is in development for testing the performance of organic working fluids in heat pipes and validation of models, for the temperature range from 423 K to 723 K. The goal of this thesis is described as: finishing the development of the TU Delft rotating heat pipe setup and use this test setup to validate the developed model. This goal was divided into several objectives.An investigation was made of what has to be done before the commissioning of the setup. It was discovered that the heat input calculation is overestimated, because insulation is not taken into account. Therefore, a new calculation was made. It is concluded that in the worst case scenario 1155 W of heat input is needed. Also, the available band heaters could not be used, therefore IR heating with quartz lamps has been considered. A calculation was made to confirm if they will provide enough power to meet the requirements of the setup. It is concluded that six quartz lamps with an effective heating length of 165 mm will provide enough power. In the fill ratio calculation, it is learned that non-annular flow is beneficial for the heat transfer compared to annular flow. Also, it was decided to fill the heat pipe with 35 grams of Dowtherm A as a start. With this amount of fluid, it is possible to operate the heat in both flow patterns over the whole temperature range. Last, it is concluded that bearing cooling is needed.Another objective was to select the required data acquisition hardware and program the required software for control and data acquisition. A compactRIO from National Instruments is selected together with several modules. This configuration is able to process all the signals and has extra capacity to handle more signals in the future. A LabVIEW program was designed to control the Delft setup. This program meets all the requirements. It has been tested with dummy signals and during a leakage test with the actual heat pipe.A model which represents the actual Delft rotating heat pipe setup has been made. The same inputs as in the Delft setup can be adjusted. This model has been developed as a network model. These types of models are often used because of their reasonably accurate and practically simple way to model transient heat pipe analysis. This model was validated with two different papers. In the first paper, an experiment is performed with a stainless steel ammonia heat pipe, which operates in non-annular flow. The data of this paper is only useful for steady state. At the steady state part, the maximum deviation is 0.96 K. In the second paper, a copper-water heat pipe is used. This heat pipe is not rotating, but has a wick. This means its behaviour is similar to a rotating heat pipe with annular flow. The data of this paper is very precise and shown in tabular form at three different points at 4 time stamps. The root-mean-square error between the experiment and the model at all data points is 0.36 K.The commissioning of the heat pipe is in progress now. When all the safety procedures are checked, the experiments can be conducted.Mechanical Engineerin
Investigating the Genetic Modifiers of Thrombosis Using the Zebrafish Model
No full textThrombosis is a leading cause of morbidity and mortality. Although 50-60% of thrombotic risk is estimated to be due to genetics, only 35% of individuals with a thrombotic event carry one of the 20-30 known genetic modifying risk factors. Antithrombin (AT3) is the primary endogenous inhibitor of the coagulation cascade, but deficiency of AT3 leads to an incompletely penetrant risk of thrombosis due to presumed genetic modifiers. The zebrafish is a small aquatic vertebrate with a well-characterized and highly conserved hemostatic system, but previous work from our laboratory suggests species specific factors allow zebrafish to survive severe hemostatic defects. This dissertation focuses on multiple areas: understanding the influence of known factors on thrombosis, developing a framework to identify novel factors and characterizing the conservation of hemostasis in zebrafish.
Zebrafish are able to survive into adulthood with a severe genetic deficiency of factor V (f5) or factor X (f10), two factors upstream of prothrombin (f2), raising the possibility of alternative pathways for thrombin generation. To rule out this possibility, a f2 knockout phenocopied the life expectancy of the f5 and f10 knockouts, confirming canonical function. The knockout led to an unexpected deletion in the kringle 1 domain and revealed a potential maturation and functional roles for (pro)thrombin. This model allows the study of the broad in vivo roles of thrombin such as cell signaling and response to inflammation that are impossible to explore in mice due to lethality.
Loss of At3 leads to larval consumptive coagulopathy followed by lethal adult thrombosis. Intercrossing knockout alleles of f2, f10 and plasminogen (plg) onto the At3-deficient zebrafish genetic background demonstrated that heterozygosity for each individual mutation improved survival in the thrombotic population. After demonstrating the feasibility of genetically suppressing thrombosis, an unbiased chemical mutagenesis screen was performed to identify novel suppressors. Four lines were established that demonstrated stable improvement in survival. A candidate approach identified frost, a point mutation in prothrombin. Heterozygosity for frost in at3-/- fish rescued both survival and the larval consumptive coagulopathy. Biochemical studies of the frost mutation demonstrated decreased prothrombin production and an inability to cleave fibrinogen. In parallel, the remaining lines were sequenced and a modern genomics pipeline confirmed the mutagenesis protocol was a successful unbiased survey, but did not achieve functional saturation of the genome. This indicates the strong potential of this protocol to identify new thrombosis biology.
Finally, loss of tissue factor (TF), a key initiating factor of the coagulation cascade, is incompatible with murine embryonic survival and studies in humans are lacking. Zebrafish have 2 copies of TF (TFa and TFb) with unknown conservation of function, and loss of function alleles for both copies were generated. Loss of both resulted in early lethality, but single copies were sufficient for normal survival. TFa and TFb were shown to have predominant roles in the arterial and venous systems, respectively. Finally, although TFb has lower in vitro procoagulant activity, it may play a role in factor VII mediated activation of the intrinsic pathway.
Overall, the work in this dissertation provides a strong foundation for studying and discovering modifiers of hemostasis and thrombosis using the zebrafish. Throughout this study, the utility of zebrafish was confirmed through the discovery of unexpected biology, demonstration of hemostatic rebalancing through thrombotic suppression and identification of promising novel alleles and pathways for informing human biology.PhDCellular & Molec Biology PhDUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/172567/1/sgrzegor_1.pd
Deeper piping erosion: Finding how to model it and what contributes to the emergence of a deeper pipe
No full textThe Netherlands is a country that is being threatened by water, both from the rivers and from the sea. The Dutch have built dikes to keep their lands from inundation. To ensure the strength and stability of these dikes, they are being assessed on the basis of several failure mechanisms. One of these failure mechanisms is Backward Erosion Piping, or piping for short. In piping, the current underneath a dike is strong enough to take soil particles with it. Tests on piping in tidal subsoil were conducted in the summer of 2021, where a pipe was found to have grown at greater depth than expected The occurrence of this deeper piping has rarely been seen before, let alone described. This lack of knowledge poses a potential safety risk, as it may underestimate the vulnerability of certain subsoil configurations. Therefore, the objective of this thesis is to develop a comprehensive understanding of deeper piping and identify the key parameters influencing its formation. To achieve this objective, a definition of deeper piping and its differentiation from conventional piping is established. Sub-mechanisms governing deeper piping are examined by analysing the forces responsible for grain movement and the forces that maintain grain stability. A Finite Element Model of the subsoil is constructed to quantify the driving forces within the subsoil, which, when combined with resisting forces, enables the determination of whether deeper piping can occur in a given subsoil configuration. To investigate the factors contributing to deeper piping, a series of simulations are conducted using this Finite Element Model. By varying the parameter values while keeping other factors constant, the influence of each parameter on the occurrence of deeper piping was examined. The analysis revealed that several key parameters significantly affect deeper piping formation, including cohesion force (𝑐), cohesion anisotropy (𝛼𝑐 ), permeability and thickness of the top layer (𝑘0 and 𝐷0, respectively), permeability of underlying layer (𝑘1), permeability anisotropy (𝛼𝑘 ) and representative grain diameter 𝑑𝑟𝑒𝑝. Also, it was found that the entrance configuration plays a large role in deeper pipe formation. These findings provide valuable insights into the mechanisms underlying deeper piping and enhance our ability to identify subsoil configurations that are prone to this phenomenon. These findings enhance the identification of subsoil configurations prone to deeper piping, thereby improving risk assessment and mitigation strategies associated with this failure mechanism. Civil Engineering | Hydraulic Engineerin
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