Academic literature on the topic 'Column unit'
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Journal articles on the topic "Column unit"
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Kh Kurbangaleeva, M. "Improving the Safety of the Rectification Unit for the Production of Alkylphenols." IOP Conference Series: Earth and Environmental Science 988, no. 2 (February 1, 2022): 022007. http://dx.doi.org/10.1088/1755-1315/988/2/022007.
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Abstract As a result of the study, the analysis of occurrence of fire hazardous situation during the operation of rectification column of production facility of one of the city’s enterprises was carried out. This installation refers to facilities for which additional safety requirements are imposed. The main danger of the operation of rectification columns and their piping used at the installation is thefear of depressurization and theinitiation of gas contamination and fire situation on the site. As theresult of the fire, the rectification column and supporting metal structures can be in flame or be under the influence of thermal radiation from the flame in adjacent column, which can lead to the collapse of structures or to losses of bearing capacity under the influence of high temperatures. Depending on the height of the column, the water supply system can have different ways of distributing water: at small height of the column, manual water nozzles are used with the use of fire hydrants; at considerable height of the columns, stationary water irrigation systems (irrigation rings) are used.
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Gaber, Maryam, Anuar Kasa, Norinah Abdul Rahman, and Jamal Alsharef. "Comparison between unit cell and plane strain models of stone column ground improvement." International Journal of Engineering & Technology 7, no. 2 (March 12, 2018): 263. http://dx.doi.org/10.14419/ijet.v7i2.8797.
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This article presents a comparative study of the behaviour of clayey soil reinforcements using stone column ground improvement by means of numerical analyses. Two-dimensional finite element analyses with commercially available software, PLAXIS, were performed on end-bearing stone columns using 15-noded triangular elements to investigate the impact of the modelling type on the stress concentration ratio and failure mechanism of an improved foundation system. Consolidation analyses were conducted throughout the study using Mohr-Coulomb’s criterion. The computed values of the stress concentration ratios were compared for different key parameters, including the diameters of stone columns, c/c spacing of columns, friction angle of stone column material, and undrained cohesion of soft soil. The major conclusions of this study were that the stone column in the unit cell model shared between 2.5 to 3.14 times more loads than the surrounding soil, whilst in the plane strain model it shared between 1.7 to 2.9 times more loads. The use of plane strain approach to model the stone column gave a more comprehensive representation of the stress distribution and load transfer between the soil and columns, in addition to being a better method than the unit cell concept to evaluate the failure mode in this system.
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Yang, Yingxin, Dongdong Song, Kuilin Huang, Haitao Ren, and Jian Zhou. "Unit Experimental Study on Impact Crushing Rock of the Microcoring PDC Bit." Shock and Vibration 2019 (November 3, 2019): 1–10. http://dx.doi.org/10.1155/2019/3173298.
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In light of the situation of sliced or powdery cuttings produced by conventional PDC bit, it is found that they are not convenient for geological logging and stratification. The unit crushing experiment which contains two breaking forms (static-pressure breaking and impact) is conducted on core columns of sandstone, limestone, and granite. This experimental study showed the following: The breaking work ratio of the three core column types is much less than that of the flat rock. The height of the core column has little effect on the bit penetration rate, while core column diameter has greater effect on the bit penetration rate. The experimental results further indicate that a core column has been generated in the central area of the drill bit, which is beneficial to the volume breaking of the rock and can improve the rock-breaking efficiency of the drill bit. The microcoring bit is suitable for raising speed in soft, medium, and hard formations and is helpful for geological logging.
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Masia, Mark J., and Nigel G. Shrive. "Carbon fibre reinforced polymer wrapping for the rehabilitation of masonry columns." Canadian Journal of Civil Engineering 30, no. 4 (August 1, 2003): 734–44. http://dx.doi.org/10.1139/l03-015.
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The use of carbon fibre reinforced polymer (CFRP) wrapping to strengthen existing cracked masonry columns was investigated experimentally. The study was aimed at quantifying the increase in strength that can be achieved and assessing the effect of column size on the strength increase. Eighteen columns were tested, with three different square cross-sectional sizes (290 mm × 290 mm, 390 mm × 390 mm, 490 mm × 490 mm) and two different types of clay masonry unit. Six columns were constructed in each size, two columns using unit type 1 and four columns using unit type 2. Strengthening was achieved by wrapping the square section columns directly with a single-layer CFRP laminate or by wrapping the columns after first casting a circular concrete jacket around the column. The latter treatment was applied to two of the small-sized columns and two of the intermediate-sized columns. All other square section columns were wrapped directly. Significant strength increases were achieved, particularly when the columns were provided with the cylindrical concrete jacket. These preliminary tests indicate that the use of CFRP wrapping is an effective technique for rehabilitating damaged masonry columns. Decisive conclusions could not be made regarding the effect of column size (cross-sectional area) on the strength increase achieved. Further tests together with nonlinear finite element modelling aimed at duplicating the experimental observations would greatly enhance the information provided by the current tests.Key words: masonry, columns, rehabilitation, strengthening, fibre reinforced polymer, experimental.
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Silva, Pedro F., and Sri Sritharan. "Seismic Performance of a Concrete Bridge Bent Consisting of Three Steel Shell Columns." Earthquake Spectra 27, no. 1 (February 2011): 107–32. http://dx.doi.org/10.1193/1.3525919.
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This paper describes the performance of a full-scale, three-column concrete bridge bent test unit that was designed, constructed, and tested under simulated in- plane seismic loads. Representing a typical bent configuration used by the Alaska Department of Transportation and Public Facilities, the test unit employed 12.7-mm-thick steel shell concrete columns and evaluated adequacy of an improved beam-to-column joint design procedure. The steel shell served as the external reinforcement and formwork for the columns. As intended, plastic hinges were fully developed in the columns adjacent to the interface with the cap beam, with minimal damage occurring to the cap beam and joints due to simulated seismic actions. These observations, along with the recorded force-displacement hysteretic response, confirmed the desirable seismic performance of the test unit. Design details, analytical response, test observations, key experimental results, and design recommendations are presented.
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Li, Zhi Miao, Ju Bao Liu, Min Luo, and Qiang Zhang. "Dynamic Finite Element Analysis and Experimental Study of Rotating Column in Cylinder." Applied Mechanics and Materials 229-231 (November 2012): 453–56. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.453.
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Rotary slender column in cylinder is a special structure in oil engineering. It contacts with outer cylinder and interacts with its inner pipe fluid and outer annular fluid. A partitioned coupling model was founded by dispersing slender column into beam element, dividing fluid domain into some sections, dispersing fluid section into hexahedron unit and transfer method of the information of coupling interface was described. Dynamics experimental device of column-liquid interaction was built to do column rotating test with considering the displacement and force boundary conditions of rotating column and testing axial excitation force of bottom column, axial acceleration of head column, transverse displacement of columns and collision and contact forces between inner columns and outer pipeline. The maximum absolute error between experimental results and numerical results is 0.31mm and this research provides the methods of numerical simulation and experimental study.
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Popov, S. V., N. Y. Krymkin, O. V. Khabibrakhmanov, and E. N. Papulovskikh. "Reconstruction of the hardware design for isopropylbenzene production for the production of ethylbenzene." Proceedings of the Voronezh State University of Engineering Technologies 83, no. 2 (September 27, 2021): 184–90. http://dx.doi.org/10.20914/2310-1202-2021-2-184-190.
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The hardware design of the rectification unit for the production of isopropylbenzene in the presence of the AlCl3 catalyst is considered, the use of which has a number of problems associated with its corrosiveness, rapid deactivation, the complexity of regeneration, etc. One of the possible solutions to the listed technological disadvantages is the use of heterogeneous zeolite-containing catalysts. In this case, during the reconstruction of the existing production of isopropylbenzene in the technological scheme of separation of alkylate, three rectification columns are released, which are expediently used to separate the alkylate of ethylbenzene production. To study the possibility of using the discharging distillation columns, a computational experiment was carried out using the Honeywell UniSim Design modeling system, in which a model of the alkylate separation unit for ethylbenzene production was formed. The NRTL method was used as a mathematical package for calculating the thermodynamic properties of the mixture components. As a result of modeling the operation of the alkylate separation unit for each distillation column, the optimal operating process parameters were obtained: pressure of the top and bottom of the column, reflux ratio, temperature profile along the height of the column. The calculated material balance of the technological scheme shows that in the first distillation column, complete separation of benzene from the alkylation reaction mass is achieved, the second column ensures the production of commercial ethylbenzene, and in the third column, a fairly clear separation of diethylbenzene from the remaining components of the mixture is obtained. The performed computational experiment showed that for the organization of the stable operation of the technological scheme for the separation of alkylate in the production of ethylbenzene, it is possible to use all the considered distillation columns without changing their design parameters at a load on the reaction mass of alkylation of about 60 t / h.
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Bucsa, Sorin, Alexandru Serban, Mugur C. Balan, Claudia Ionita, Gabriel Nastase, Catalina Dobre, and Alexandru Dobrovicescu. "Exergetic Analysis of a Cryogenic Air Separation Unit." Entropy 24, no. 2 (February 13, 2022): 272. http://dx.doi.org/10.3390/e24020272.
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This case study analyzes a cryogenic air separation unit (ASU) with a production of V˙O2=58,300 [m3Nh] of gaseous oxygen with a concentration greater than 98.5%, operating in Romania on a steel plant platform. The goal of the paper is to provide an extensive model of exergetic analysis that could be used in an optimization procedure when decisional parameters are changed or structural design modifications are implemented. For each key part of the Air Separation Unit, an exergetic product and fuel were defined and, based on their definition, the coefficient of performance of each functional zone was calculated. The information about the magnitude of the exergetic losses offers solutions for their future recovery. The analysis of the exergy destructions suggests when it is worth making a larger investment. The exergetic analysis of the compression area of the ASU points out an exergy destruction and loss of 37% from the total plant’s electrical energy input. The exergy loss with the heat transferred to the cooling system of compressors can be recovered; for the exergy destruction portion, the challenge between investment and operating costs should be considered. The exergy destruction of the air separation columns found the High Pressure Column (HPC) to be more destructive than the Low Pressure Column. The share of the exergy destruction in the total plant’s electrical energy input is 8.3% for the HPC. The local COP of the HPC, calculated depending on the total exergy of the local product and fuel, is 62.66%. The calculus of the air separation column is performed with the ChemSep simulator.
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Beler-Baykal, B., G. Witte, and I. Sekoulov. "Activated carbon and residual nitrification for higher quality effluents for the coastal areas." Water Science and Technology 46, no. 8 (October 1, 2002): 99–104. http://dx.doi.org/10.2166/wst.2002.0153.
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Efforts for the task of modification of a nitrification/denitrification unit operating in a series of two fixed bed columns are outlined. The problem was elevated dissolved oxygen concentrations at the entrance of the denitrification column, resulting in an excessive consumption of methanol. The possibility of using a column of activated carbon for adsorption alone and in which both adsorption and residual nitrification take place was investigated. The results were observed to be very satisfactory in reducing dissolved oxygen levels to practically zero at the entrance of the denitrification unit especially for the case where both adsorption and residual nitrification were employed.
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Khabbazian, Majid, Victor N. Kaliakin, and Christopher L. Meehan. "Column Supported Embankments with Geosynthetic Encased Columns: Validity of the Unit Cell Concept." Geotechnical and Geological Engineering 33, no. 3 (January 18, 2015): 425–42. http://dx.doi.org/10.1007/s10706-014-9826-8.
Full textDissertations / Theses on the topic "Column unit"
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Cruz, Eva Brunilda. "A Comprehensive Dynamic Model of the Column Flotation Unit Operation." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30748.
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The core of this project was the development of a column flotation dynamic model that can reasonably predict the changes in the concentrations of all solid and bubble species, along the full column height. A dynamic model of a process is normally composed of a set of partial or ordinary differential equations that describe the state of the process at any given time or position inside the system volume. Such equations can be obtained from fundamental material and/or energy balances, or from phenomenological derivations based on knowledge about the behavior of the system. A phenomenological approach referred to as population balance modeling was employed here.
Initially, a two-phase model was formulated, which represents the behavior of the gas phase in a frother solution. The column was viewed as consisting of three main regions: a collection region, a stabilized froth and a draining froth. Experiments were carried out, based on conductivity techniques, for obtaining empirical data for model validation and parameter estimation. After testing the two-phase model, the equations for the solid species were derived. Consideration of the effects of bubble loading, slurry density and slurry viscosity on bubble rise velocity and, therefore, on air fraction is included in the model. Bubble coalescence in the froth is represented as a rate phenomenon characterized by a series of coalescence efficiency rate parameters. Auxiliary equations that help describe the settling of free particles, the buoyancy of air bubbles, and the processes of attachment and detachment, were also developed and incorporated into the model. The detachment of solids from the bubbles in the froth zones was attributed to coalescence, and it was assumed to be proportional to the net loss of bubble surface area.
Almost all parameters needed to solve the model equations are readily available. The set of differential equations that comprise the model can be solved numerically by applying finite difference approximation techniques. An iteration has to be performed, which involves calculating the product flowrate at steady state, modifying the tailings rate and solving the model again until a mass balance is satisfied.Ph. D.
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Callahan, Justin. "Prediction of the Performance of a Flexible Footing on a Stone-Column Modified Subgrade." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4450.
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When foundations are designed on weak clay layers, it is a common practice to modify the subgrade by installing stone columns. Currently used methods for determining the level of ground modification, represented by the percentage of soil replaced (replacement ratio), assume a rigid foundation. These analytical methods provide the designer with the potential settlement reduction based on the compressibility parameters of the subgrade and the replacement ratio. The deficiencies of these methods are the assumption of rigidity of the foundation and the consideration of the settlement reduction as the only design criterion. Furthermore, they do not consider the effects that ground modification has on differential settlement, moments, and shear forces within the slab.
In order to determine the effects of ground modification on the overall performance of a flexible foundation, a computer program was formulated which compares a multitude of design parameters of the modified subgrade to those of the unmodified subgrade to determine the impact of ground modification. By performing this investigation, correlations were found between the replacement ratio and the settlement reduction factors. Similarly, correlations were also found between the ratio of the length of the foundation to the radius of relative stiffness, and the moments and shear forces generated within the slab. The use of the findings of this thesis would allow the design to make more informed decisions when designing foundations on modified subgrade resulting in safer and more economical designs.
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Bergeot, Ghislain. "Extension du concept "One-column" au lit mobile simulé réactif : application à la séparation réactive des C8 aromatiques." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL057N/document.
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La séparation des C8 aromatiques par Lit Mobile Simulé (LMS) permet d'obtenir du paraxylène (PX) pur. Les autres composés du mélange sont recyclés dans un réacteur afin d'être isomérisés puis séparés à nouveau. La charge du LMS est composée à environ 75% par ce flux de recyclage. L'intégration de la réaction dans le LMS, réalisée en intercalant des réacteurs d'isomérisation entre les lits d'adsorbant de la zone 3 (procédé LMS Réactif, LMSR), doit permettre une réduction de ce flux de recyclage.L'objectif de cette thèse est de développer une méthodologie d'étude des procédés de type Lit Mobile Simulé (LMS) et Lit Mobile Simulé Réactif (LMSR) basée sur :-un outil expérimental simplifié : le pilote One-column réactif (OCR)-des simulateurs One-column réactif ou non qui seront validés par les résultats expérimentaux du pilote-des simulateurs LMS et LMSR permettant d'accéder aux résultats des procédés industriels.Les simulations de One-column (OC) montrent une bonne sensibilité aux paramètres clés de la séparation des C8 aromatiques (sélectivité PX/EB et diffusion intracristalline). Les résultats expérimentaux font ressortir des difficultés importantes à mettre en œuvre le OC expérimentalement. Plusieurs hypothèses sont exposées pour expliquer les résultats obtenus mais les difficultés rencontrées limitent, en l'état, l'utilisation du pilote pour l'étude de la séparation (réactive ou non) des C8 aromatiques.L'étude du LMSR effectuée par simulation montre l'importance du nombre et de l'emplacement des réacteurs ainsi que de l'intégration du LMSR dans la boucle de production de PX. L'usage du LMSR pour la production de PX permet une réduction importante du débit de recyclageToday, pure paraxylene (PX) is mainly obtained from a mix of C8 aromatics by a separation process based on adsorption: the Simulated Moving Bed (SMB). The other components of the blend are sent to an isomerisation reactor and are recycled to the SMB. 75% of the SMB feed flow rate come from this recycle flow. Coupling reaction and separation by inserting isomerisation reactors between the adsorption beds of the third zone (Simulated Moving Bed Reactor, SMBR) should allow a reduction of this recycling flow rate.The main objective of this thesis is to develop a new methodology for studying SMB and SMBR processes based on:- a simplify experimental tool : the One-column reactive (OCR) pilot unit- simulators of the OCR which will be validated by the experimental results obtain on the pilot unit- simulators of SMB and SMBR processes which give access to industrial processes results.Simulation results show that OC system seem to be sensitive to key parameters of C8 aromatics separation (PX/EB selectivity and micropore diffusivity). Results on the pilot unit highlight the difficulties to implement an experimental OC. Hypothesis are given to explain those results but, without modification, OCR pilot unit cannot be used to study xylene separation (with or without reaction).SMBR study done by simulation shows the impact of the placement and the number of reactors. Integration of SMBR in the global PX production scheme is also essential. SMBR allows an important reduction of recycling flow rate (up to 50%)
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Šmarda, Michael. "Zjednodušený úvodní projekt uzlu destilace." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228156.
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The target of diploma thesis was to improve author’s theoretical and practical design knowledge of process engineering. In the diploma thesis a Simplified Basic Engineering Project of distillation unit has been developed. It was necessary to become familiar with the process technology and formal requirements of Basic Engineering Project. The most important parts of Basic Engineering Project are material and heat balances. Material and heat balances are the corner stones of distillation unit equipment design. Parameters of process equipment are presented in the form of equipment datasheets. The specification of pipelines is based on material and heat balances too. Inevitable part of Basic Engineering are Process Flow Diagram and Piping and Instrumentation Diagram (PFD & PID). Process Flow Diagram and Piping and Instrumentation Diagram include all equipment, piping and basic control loops.
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Bilko, Tomáš. "Návrh okruhu hydrostatického řízení traktoru Forterra." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-231014.
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The topic of this thesis is strength check of hydrostatic steering circuit for Zetor Forterra HSX tractor. Next part of the thesis deals with steering column support structure and pedal group console design including FEM analysis, allowing installation of steering columns of different types.
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Бабенко, Володимир Миколайович. "Закономірності гідродинаміки і масообміну в процесах ректифікації суміші розчинників на новому контактному пристрої." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22718.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.17.08 – процеси та обладнання хімічної технології. – Національний технічний університет "Харківський політехнічний інститут" Міністерства освіти і науки України, м. Харків, 2016.
Дисертацію присвячено дослідженню процесу поділу рідинних гетерогенних сумішей на регулярних контактних пристроях з різними геометричними параметрами насадочних елементів. Досліджено механізм процесу утворення рідинної плівки для колонних апаратів, що застосовуються в ректифікації у відповідності з гідродинамічними характеристиками процесу. Показано, що основним фактором інтенсифікації масообмінного процесу для регулярних контактних елементів, є швидкість відновлення рідинної плівки. Доведено що, основними факторами, які визначають ефективність процесу поділу суміші розчинників, є низький питомий опір апарату по газу і конструктивні особливості контактних елементів ректифікаційній колони. Отримано графічні та емпіричні залежності для розрахунку висоти насадочного шару, питомої поверхні насадки в залежності від лінійної швидкості газу в колонному апараті і геометричних параметрів насадочних пристроїв. Розроблено практичні рекомендації для проектування колонних установок з високими енергетичними показниками. Запропоновано новий регулярний контактний елемент, який поєднує в собі велику питому поверхню з малим гідродинамічним опором. Запропоновано принципову апаратурно-технологічну схему процесу поділу суміші розчинників, яка розроблена й впроваджена на виробництві ПАТ "ФАРМСТАНДАРТ-БІОЛІК" (м. Харків).Dissertation for the degree of candidate of engineering sciences on specialty 05.17.08 – processes and equipment of chemical technology. – National technical university "Kharkiv Polytechnic Institute" of the Ministry of Education and Science of Ukraine, Kharkiv, 2016. The dissertation is dedicated to the study of the separation process of liquid heterogeneous mixtures on the regular contact devices with different geometric parameters of the packing elements. The mechanism of the liquid film formation for the column apparatuses utilized in rectification is investigated according to the hydrodynamic characteristics of the process. It is shown that the main factor in the intensification of mass transfer processes for regular contact devices is velocity recovery of the liquid film. It is proved that the main factors of the solvent mixture separation efficiency are low specific resistance of an apparatus for a gas and constructional characteristics of the contact devices of a rectification column. Graphical and empirical relationships are obtained to calculate height of the packed bed, specific surface of a nozzle, depending on the linear gas velocity in a column apparatus and geometric parameters of the packing devices. Practical recommendations for the design of column units with high energy performance are developed. A new regular contact element that combines large surface area with low hydrodynamic resistance is suggested. A process flow diagram of the solvent mixtures separation is given, which was developed and implemented in the production line of PJSC "PHARMSTANDARD-BIOLIK" (Kharkiv city).
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Бабенко, Володимир Миколайович. "Закономірності гідродинаміки і масообміну в процесах ректифікації суміші розчинників на новому контактному пристрої." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22717.
Full textAbstract:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.17.08 – процеси та обладнання хімічної технології. – Національний технічний університет "Харківський політехнічний інститут" Міністерства освіти і науки України, м. Харків, 2016.
Дисертацію присвячено дослідженню процесу поділу рідинних гетерогенних сумішей на регулярних контактних пристроях з різними геометричними параметрами насадочних елементів. Досліджено механізм процесу утворення рідинної плівки для колонних апаратів, що застосовуються в ректифікації у відповідності з гідродинамічними характеристиками процесу. Показано, що основним фактором інтенсифікації масообмінного процесу для регулярних контактних елементів, є швидкість відновлення рідинної плівки. Доведено що, основними факторами, які визначають ефективність процесу поділу суміші розчинників, є низький питомий опір апарату по газу і конструктивні особливості контактних елементів ректифікаційній колони. Отримано графічні та емпіричні залежності для розрахунку висоти насадочного шару, питомої поверхні насадки в залежності від лінійної швидкості газу в колонному апараті і геометричних параметрів насадочних пристроїв. Розроблено практичні рекомендації для проектування колонних установок з високими енергетичними показниками. Запропоновано новий регулярний контактний елемент, який поєднує в собі велику питому поверхню з малим гідродинамічним опором. Запропоновано принципову апаратурно-технологічну схему процесу поділу суміші розчинників, яка розроблена й впроваджена на виробництві ПАТ "ФАРМСТАНДАРТ-БІОЛІК" (м. Харків).Dissertation for the degree of candidate of engineering sciences on specialty 05.17.08 – processes and equipment of chemical technology. – National technical university "Kharkiv Polytechnic Institute" of the Ministry of Education and Science of Ukraine, Kharkiv, 2016. The dissertation is dedicated to the study of the separation process of liquid heterogeneous mixtures on the regular contact devices with different geometric parameters of the packing elements. The mechanism of the liquid film formation for the column apparatuses utilized in rectification is investigated according to the hydrodynamic characteristics of the process. It is shown that the main factor in the intensification of mass transfer processes for regular contact devices is velocity recovery of the liquid film. It is proved that the main factors of the solvent mixture separation efficiency are low specific resistance of an apparatus for a gas and constructional characteristics of the contact devices of a rectification column. Graphical and empirical relationships are obtained to calculate height of the packed bed, specific surface of a nozzle, depending on the linear gas velocity in a column apparatus and geometric parameters of the packing devices. Practical recommendations for the design of column units with high energy performance are developed. A new regular contact element that combines large surface area with low hydrodynamic resistance is suggested. A process flow diagram of the solvent mixtures separation is given, which was developed and implemented in the production line of PJSC "PHARMSTANDARD-BIOLIK" (Kharkiv city).
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Dong, Chunxiao, and 董春宵. "Uni-axial behaviour of concrete-filled-steel-tubular columns with external confinement." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/195975.
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This thesis studies the uni-axial behaviour of circular double-skinned concrete-filled-steel-tubular (CFST) columns with external confinement in form of external steel rings. Particular attention is paid to the experimental behaviour of double-skinned CFST columns and theoretical model for evaluating the loadcarrying capacity of un- and ring-confined double-skinned CFST columns.
Experimental studies on circular double-skinned CFST columns with various spacing of confinement, concrete strength and hollow ratio were conducted and discussed comprehensively. The mechanical properties of double-skinned CFST columns such as elastic stiffness, elastic strength, load-carrying capacity and ductility are presented. From the result, it is found that the elastic stiffness, elastic strength, load-carrying capacity and ductility are enhanced by installing the external steel rings to the outer tube as external confinement. To verify the effectiveness of external steel rings, the Poisson’s ratios of the double-skinned CFST columns are listed and found to be similar to that of concrete so that a perfect bonding is maintained. To emphasis the excellent performance of double-skinned CFST columns with external rings under uni-axial compression, the load-carrying capacity, elastic strength and elastic stiffness are compared to those of single-skinned CFST columns and reinforced concrete columns.
To fill up the gap that no design model is provided in Eurocode 4 (EC4) for confined double-skinned CFST columns, a theoretical model based on the force equilibrium condition is proposed for evaluating the load-carrying capacity of both un- and ring-confined double-skinned CFST columns. The model takes into account the composite action between the steel tubes and core concrete. To verify the proposed model, numerous test results obtained by the author and other researchers are used for comparing the theoretical results.
According to the above theoretical model above, a parametric study is carried out to investigate the effect of various geometry and material properties on the load-carrying capacity of double-skinned CFST columns. The confining pressure is expressed in terms of geometry and material factors. A simplified design formula is proposed to facilitate the preliminary design of double-skinned CFST columns with and without external confinement.published_or_final_version
Civil Engineering
Master
Master of Philosophy
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Luo, Lie, and 罗冽. "Uni-axial behavior of normal-strength concrete filled steel tubular columns with external confinement." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49618210.
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This thesis proposes two forms of external confinement for concrete filled steel tubular (CFST) columns. The confinement efficiency is studied by examining the axial strength enhancement and ductility improvement of the CFST columns with external confinement.
Due to the heavy demand of confining steel to restore the column ductility in seismic regions, it is more efficient to confine these columns by hollow steel tube to form CFST column. Compared with transverse reinforcing steel, steel tube provides a stronger and more uniform confining pressure to the concrete core, and reduces the steel congestion problem for better concrete placing quality. The CFST columns are therefore characterised by higher strength, ductility and large energy absorption before failure.
However, a major shortcoming of CFST columns is the imperfect steelconcrete interface bonding occurred at the elastic stage as steel dilates more than concrete in compression. This adversely affects the confining effect and decreases the elastic modulus. To resolve the problem, it is proposed in this thesis to use external steel confinement in the forms of rings and ties to restrict the dilation of steel tube. For verification, a series of uni-axial compression test was performed on some CFST columns with external steel rings and ties. From the results, it was found that the external steel rings could improve both the axial strength and stiffness of the CFST columns significantly. However, the steel ties could not improve either the axial strength or elastic stiffness significantly. The confining efficiency was then investigated by comparing the strength of these confined-CFST columns with the reinforced concrete (RC) columns counterparts with the same concrete and steel volume. It is evident that the axial strength of CFST columns is much higher than the RC columns, which suggests that the application of CFST columns can utilise less construction materials and reduce the demolition waste.
A theoretical model is also proposed for predicting the axial strength of ring-confined CFST columns. Comparison between the predicted results and the test results obtained by the author and other researchers shows that the proposed model gives good estimation for both unconfined and confined CFST columns.published_or_final_version
Civil Engineering
Master
Master of Philosophy
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Falcón, Cisneros Javier Antonio. "Simulación por elementos finitos y validación de un modelo virtual de la columna lumbar humana." Universidad Nacional de Ingeniería. Programa Cybertesis PERÚ, 2008. http://cybertesis.uni.edu.pe/uni/2008/falcon_cj/html/index-frames.html.
Full textBooks on the topic "Column unit"
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Powell, Colin L. My American journey. New York: Ballantine Books, 2003.
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E, Persico Joseph, and Suzuki Chikara 1934-, eds. Mai Amerikan jānī: Korin Paueru jiden. Tōkyō: Kadokawa Shoten, 2001.
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E, Persico Joseph, ed. My American journey. New York: Random House, 1995.
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E, Persico Joseph, ed. Wo di Meiguo zhi lü: Bao'er jiang jun zi zhuan. Taibei Shi: Zong jing xiao Zhen de tu shu shi yeh yu xian gong si, 1996.
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MOSBY. Radiographic Anatomy, Positioning and Procedures: Unit 8: Vertebral Column CD-ROM. Mosby, 1996.
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Anderson, James A. Cerebral Cortex. Oxford University Press, 2018. http://dx.doi.org/10.1093/acprof:oso/9780199357789.003.0011.
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There is important local processing in cortex as well as the more dramatic massive projections back and forth between cortical regions. Using short, slow, local connections eliminates many long, expensive, fast interregional connections. Cortical pyramidal cells connect to neighbors over several millimeters in the form of patchy connections. Connections are often reciprocal between patches. Groups of cells called cortical columns are ubiquitous in cortex and seem to be fundamental architectural units. A functional column is perhaps .3 mm in diameter containing perhaps 10,000 cells. Intrinsic imaging studies of columns in inferotemporal cortex show they respond selectively to complex aspects of images. A small number of columns respond to a complex object. In inferotemporal cortex, these responses might be “words” in a language of vision. There is evidence for scaling of computation from single units to cortical regions. Understanding the function of such ensembles is the future.
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Sternbach, Marion. Apheresis in the ICU. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0268.
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This chapter describes therapeutic plasma exchange, as well as cytapheresis for hyperleukocytosis and essential thrombocythemia, as well as harvesting haematological stem cells (HSC) for transplantation. Instrumentation and techniques are mostly density centrifugation, much less column adsorption for antibodies or membrane filtration for noxious molecules. Pathophysiology of apheresis is dealt with in great detail with emphasis on prevention and treatment of side effects, much more critical in the intensive care unit (ICU) setting. Main manifestations are: hypocalcaemia due to chelation by anticoagulants, hypo- and less hypervolaemia, allergic reactions to sedimenting and volume replacement starches or plasma, depletion of coagulation factors, vitamin K, immunoglobulins, lymphocytes with long lifespan and platelets. Wash-out of drugs for comorbid or underlying conditions occurs inadvertently. Main indications for plasma exchange are thrombotic thrombocytopenic purpura (TTP)/haemolytic uraemic syndrome (HUS) with plasma or cryo-poor supernatant (based on RCT), hyperviscosity syndromes, post-transfusion purpura (PTP) and auto-immune haemolytic anaemia (AIHA), where all other treatments have failed. In cold agglutinin disease, cryoglobulinaemia, coagulation factor inhibitors and ABO incompatible HSC transplants, plasmapheresis has proven useful. Myeloma with renal failure does not seem to benefit significantly from plasma exchange (randomized controlled trials proven).
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Burton, Derek, and Margaret Burton. The skeleton, support and movement. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198785552.003.0003.
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Buoyancy largely supports fish, reducing the role of the skeleton, which functions as an attachment for muscle involved in movement and in protection, as exoskeleton (scales, scutes, bony plates) and as endoskeleton (vertebral column, skull). The general organization of fish skeletons and their component parts are described, as well as bone and cartilage. The interesting occurrence of acellular bone, additional to cellular bone, in teleosts is considered. Fish show metameric segmentation with myotomes on either side of the vertebral column, the latter acting as a compression strut, preventing shortening. Myotome muscle is organized into linear units named sarcomeres which contract by means of protein fibres, myosin and actin, sliding past each other. Usually fish body wall muscles occur as a thin outer layer of aerobic red muscle, with an inner thick region of anaerobic white muscle. Interspecific variability in the relative roles of myotomes and fin musculature in swimming is discussed.
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Bogdanovic, Jelena. The Framing of Sacred Space. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780190465186.001.0001.
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The Framing of Sacred Space offers the first topical study of canopies as essential spatial and symbolic units in Byzantine-rite churches. Centrally planned columnar structures—typically comprising four columns and a roof—canopies had a critical role in the modular and additive processes of church design, from actual church furnishings in the shape of a canopy, to the church’s structural core defined by four columns and a dome. As architectonic objects of basic structural and design integrity, canopies integrate an archetypical image of architecture and provide means for an innovative understanding of the materialization of the idea of the Byzantine church and its multifocal spatial presence. The book considers both the material and conceptual framing of sacred space and explains how the canopy bridges the physical and transcendental realms. As a crucial element of church design in the Byzantine world, a world that gradually abandoned the basilica as a typical building of Roman imperial secular architecture, the canopy carried tectonic and theological meanings and, through vaulted, canopied bays and recognizable Byzantine domed churches, established organic architectural, symbolic, and sacred ties between the Old and New Covenants. In such an overarching context, the canopy becomes an architectural parti, a vital concept and dynamic design principle that carries the essence of the Byzantine church. The Framing of Sacred Space highlights significant factors in understanding canopies through specific architectural settings and the Byzantine concepts of space, thus also contributing to larger debates about the creation of sacred space and related architectural “taxonomy.”
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Keats, Jonathon. Virtual Words. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780195398540.001.0001.
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The technological realm provides an unusually active laboratory not only for new ideas and products but also for the remarkable linguistic innovations that accompany and describe them. How else would words like qubit (a unit of quantum information), crowdsourcing (outsourcing to the masses), or in vitro meat (chicken and beef grown in an industrial vat) enter our language? In Virtual Words: Language on the Edge of Science and Technology, Jonathon Keats, author of Wired Magazine's monthly Jargon Watch column, investigates the interplay between words and ideas in our fast-paced tech-driven use-it-or-lose-it society. In 28 illuminating short essays, Keats examines how such words get coined, what relationship they have to their subject matter, and why some, like blog, succeed while others, like flog, fail. Divided into broad categories--such as commentary, promotion, and slang, in addition to scientific and technological neologisms--chapters each consider one exemplary word, its definition, origin, context, and significance. Examples range from microbiome (the collective genome of all microbes hosted by the human body) and unparticle (a form of matter lacking definite mass) to gene foundry (a laboratory where artificial life forms are assembled) and singularity (a hypothetical future moment when technology transforms the whole universe into a sentient supercomputer). Together these words provide not only a survey of technological invention and its consequences, but also a fascinating glimpse of novel language as it comes into being. No one knows this emerging lexical terrain better than Jonathon Keats. In writing that is as inventive and engaging as the language it describes, Virtual Words offers endless delights for word-lovers, technophiles, and anyone intrigued by the essential human obsession with naming.
Book chapters on the topic "Column unit"
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Shiina, Takayuki, Takahiro Yurugi, Susumu Morito, and Jun Imaizumi. "Unit Commitment by Column Generation." In Operations Research Proceedings, 559–65. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28697-6_78.
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Guyot, F., F. Alexandre, J. P. Haton, and Y. Burnod. "A Potentially Powerful Connectionist Unit: The Cortical Column." In Neurocomputing, 369–77. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76153-9_43.
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Loureiro, J. M., S. A. Figueiredo, M. M. Alves, Z. P. Lu, and A. A. Rodrigues. "Algebraic Prediction of the Behavior of a Three-step One Column PSA Unit." In The Kluwer International Series in Engineering and Computer Science, 545–52. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4613-1375-5_68.
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Bakri, Zulhazmee, Zakiah Ahmad, and Atikah Fatma Md Daud. "Behavior of Reinforced Masonry Column Under Axial Loading Using Sand Quarry Dust Modular Unit." In InCIEC 2013, 597–610. Singapore: Springer Singapore, 2014. http://dx.doi.org/10.1007/978-981-4585-02-6_52.
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Mott, Robert L., and Joseph A. Untener. "Columns." In Applied Strength of Materials, Sixth Edition SI Units Version, 631–70. Sixth edition, SI units version. | Boca Raton : Taylor & Francis, CRC Press, 2018.: CRC Press, 2017. http://dx.doi.org/10.1201/9781315153056-11.
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Ottenheym, Konrad, and Krista De Jonge. "I: Of Columns and Wooden Piles. The Foundations of Architectural Theory in the Low Countries 1560-1625." In Unity and Discontinuity, 93–110. Turnhout: Brepols Publishers, 2007. http://dx.doi.org/10.1484/m.archmod-eb.4.00119.
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Lai, M. H., and J. C. M. Ho. "Expereimental Uni-axial Behaviour of UHSCFST Columns with External Confinement." In Lecture Notes in Civil Engineering, 705–21. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-7603-0_68.
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Burnod, Yves. "Multicellular Processing Units for Neural Networks: Model of Columns in the Cerebral Cortex." In Neurocomputing, 359–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76153-9_42.
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Lansner, Anders, and Erik Fransén. "Improving the Realism of Attractor Models By using Cortical Columns as Functional Units." In The Neurobiology of Computation, 251–56. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-2235-5_41.
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Cowan, G. H. "Development of Physical and Mathematical Modelling Methods for Scale-Up of Batch Stirred Tank and Packed-Bed Column Adsorption and Chromatographic Units." In Adsorption: Science and Technology, 517–37. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2263-1_27.
Full textConference papers on the topic "Column unit"
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Liu, Mingyue, Longfei Xiao, Yufeng Kou, and Haining Lu. "Numerical Study on Vortex-Induced Motions of Semi-Submersibles With Various Types of Columns." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-62355.
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Vortex-induced motions (VIM) of offshore floaters occur when the frequency of the vortex shedding is close to the natural frequency in the transverse direction of the unit subjected to the current, and this can severely affect the fatigue life of mooring lines and risers. Literatures in recent years have shown an increasing interest in the VIM behavior of semi-submersibles (SS), the geometry of which implies a more complex VIM phenomenon. In the case of multi-column semi-submersibles, the vortices shed around each column. Thus the shape of the columns, circular or square, and the wake interference different for each current heading, characterize the VIM of the unit. Based on verification by the VIM towing tests for a semi-submersible with four rounded square columns, VIM simulations were conducted using CFD method in the model scale for four semi-submersibles with different column designs: a SS model with four rounded square columns (SRC-SS), a SS model with four circular columns (CC-SS), a SS model with two tandem rounded square columns and two tandem circular columns (SRCT-CCT-SS), and a SS model with two staggered rounded square columns and two staggered circular columns (SRCS-CCS-SS). The current headings ranged from 0° to 180° and reduced velocities of 4 up to 14 were considered. Different semi-submersibles present different VIM performances owing to the influence of the column design. The most significant transverse motions of the CC-SS model occur at the 0° current heading with the largest nominal transverse amplitudes around 74% of the column diameter. On the other hand, the maximum amplitudes in the transverse direction of the SRC-SS model, approximately 63% of the column width, are observed at the 45° current heading. Additionally, the VIM responses could be mitigated when the semi-submersible consists of combined circular-section and square-section columns.
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Bereznitski, Alexei. "A Novel Design of Mobile Offshore Drilling Unit for Arctic Conditions." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49137.
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Exploration of Arctic offshore for oil and gas sets extremely high requirements for Mobile Offshore Drilling Units (MODU). Arctic offshore is one of the harshest environments on the planet. Low temperatures, high winds and ice infested waters represent great challenge. Drilling units, which are optimized for severe ice loads, are vulnerable to waves when water clears from the ice. MODU’s specifically designed for open water and extreme waves have poor ice resistant performance. A Novel Design of column stabilized Mobile Offshore Drilling Unit named JBF Arctic is presented in the paper. The major feature of the unit is the combination of exceptional seakeeping characteristics and excellent ice resistance. This is achieved by utilization of a dual draft concept. In open water the unit has a draft which is typical for column stabilized units. In ice the unit is submerged to a deeper draft where a cone shaped heavily reinforced upper structure receives the ice loads. This paper deals with results of extensive research including seakeeping calculations, model testing in a seakeeping tank, studies on ice loads, model testing in an ice tank, and analysis of the mooring system.
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Chou, Frank, John Chianis, and Xinyu Zhang. "Self-Installed Single Column Floater." In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51466.
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This paper introduces a novel floating production platform concept for exploration and production of oil and gas in ultra deep water. The developmental effort has been supported by ABB in-house research and development budget. This novel production unit is an enhanced version of ABB Self-Installed Single Column Floater (SISCF) concept. This unit is envisioned to be completely assembled at quayside, towed to location, and be installed vertically to its target draft without the need of a major crane vessel. This enhanced feature reduces the wind load on the deck and hull significantly during wet tow as well as alleviates the uncertainty on the duration of an offshore operation, thereby widens the weather window for installation, hook-up and commissioning offshore. The enhanced SISCF (ESISCF) hull consists of four major components i.e., hard tank with center opening, soft tank with telescoping truss members and opening, permanent-stability ring, and three (3) telescoping support columns. During the installation phase, the telescoping columns are used to guide the permanent-stability ring, which provided needed stability in the installation phase. In addition, because of the way center truss being constructed, the hard tank is collapsed (or sit) right on top of the soft tank during wet tow thus reduced the wind arm (almost 100 ft) and wind forces. In its in-place position, ESISCF motion responses in waves are found to be excellent because of its deep draft. The current concept combines the advantages of a spar and a semi-submersible vessel. The paper will detail the concept, and outline the fabrication to installation scenario. The principal dimensions of a typical ESISCF for a given payload will be presented together with its stability and motion responses in waves based on the sea conditions representing a typical geographical area of Gulf of Mexico. The advantages of this concept will be explained in detail.
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Guo, Ying, Jianhong Lu, and Tongshu Guo. "Control-oriented dynamic modeling of the air separation unit column in IGCC." In 2011 International Conference on Electronics, Communications and Control (ICECC). IEEE, 2011. http://dx.doi.org/10.1109/icecc.2011.6067983.
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Cha´vez, Rosa H., Javier de J. Guadarrama, Osbaldo Pe´rez, and Abel Herna´ndez-Guerrero. "Influence of the Cross Sectional Area of a Separation Column Using Structured Packing." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43918.
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In order to determine the dimension of a separation column, hydrodynamic and mass transfer models are necessary to evaluate the pressure drop and the height of the global mass transfer unit, respectively. Those parameters are a function of the cross sectional area of the column. The present work evaluates the dependency of the pressure drop and height of the global transfer unit with respect to the cross sectional area of the column, using an absorption column with high efficiency structured packing, in order to recover SO2 in the form of NaHSO3, as an example. An optimization was done applying Two Film model which is based on the number of global mass transfer units of both gas and liquid, involving the separation efficiency in terms of the height of a global transfer unit. Structured packing, geometrically heaped in a separation column, has been achieving wider acceptance in the separation processes due to their geometric characteristics that allow them to have greater efficiency in the separation processes. Three different structured packing were evaluated in this work. The results show how ININ packing is one of the packings does the best work having the highest separation efficiency because it has the lowest height of the global mass transfer unit and Mellapak packing has the largest capacity because it manages the largest liquid and gas flows. An analysis is done with respect to the pressure drop through the system for all packings considered, and a discussion is presented for each hydrodynamic and mass transfer parameter studied.
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Kim, Joo-Sung, Seon Oh Yoo, Hyun Joe Kim, Jong Hun Lee, So Lyoung Han, and Dong Yeon Lee. "Experimental and Numerical Study of Horizontal Wave Impact Loads for a Semi-Submersible Drilling Unit." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96236.
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Abstract A semi-submersible drilling unit model was tested to estimate horizontal wave impact loads on vertical side of deckbox following the procedure recommended by DNVGL OTG-14. The present model test data show that there is clear difference in the relationships between upwell and horizontal wave impact pressure between near column/pontoon and around centerline. Near column and pontoon, not only is the maximum pressure much lower but the pressure increases more smoothly to its maximum value, compared to those of centerline. CFD simulations with focusing breaking waves have been made to examine the effect of wave-body interaction on horizontal wave impact on deck-box. The present CFD simulation results clearly show that the flows in front of column are strongly accelerated in vertical direction by blocking effect of column and pontoon, eventually producing strong run-up jets. The run-up jets in the present study are so strong that the direct impact of the incoming breaker on the wall does not occur, which leads to much smaller peak pressures, compared to those of centerline.
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Tahar, Arcandra, and Lyle Finn. "Vortex Induced Motion (VIM) Performance of the Multi Column Floater (MCF)–Drilling and Production Unit." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-50347.
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This paper presents the VIM model tests of the Multi Column Floater (MCF). The MCF is a new drilling and production deep-draft semisubmersible platform developed by Horton Wison Deepwater in Houston. A vertically restrained well deck or Multi Riser Buoyancy Can (MRBC) configured in the center of the MCF is a technology enabler for dry tree semisubmersible. The MRBC independently supports and tensions the production and drilling risers. The production risers may be a combination of dry tree risers and subsea tree tubing risers. VIM model tests were carried out at the FORCE Technology basin during the period of September-October, 2007 for the internal study. The test emphasis was to understand the physical behavior of the MCF at model scale so that a thorough correlation study could be carried out. The inplace model test analysis as well as comparison with numerical tools has been published in the OMAE2010-20640 paper [1]. VIM performance of the MCF that uses cellular construction for the columns is the focus of this paper. The 1:55.88 scale model tests were conducted. The MCF mooring stiffness, riser stiffness, natural periods and mass properties were closely matched with target full-scale properties. The MCF was tested without strakes. A wide range of towing speeds in 3 headings was covered in the test programs. The VIM response was measured for different reduced velocity (Ur). A total of 38 tests were done.
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Tahar, Arcandra, and Lyle Finn. "Inplace Model Test Result Correlation of Multi Column Floater (MCF): Drilling and Production Unit." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20640.
Full textAbstract:
This paper presents the comparison of model tests and numerical results of Multi Column Floater (MCF). MCF is a new drilling and production deep-draft semisubmersible platform developed by Horton Wison Deepwater in Houston. A vertically restrained well deck or Multi Riser Buoyancy Can (MRBC) configured in the center of the MCF is technology enabler for dry tree semisubmersible. The MRBC independently supports and tensions the production and drilling risers. The production risers may be a combination of dry tree risers and subsea tree tubing risers. Inplace model tests were carried out at the FORCE Technology basin during the period September-October, 2007 for the internal study. The test emphasis was to understand the physical behavior of MCF at model scale so that a thorough correlation study could be carried out. MCF mooring stiffness, riser stiffness, natural periods and mass properties of the model were closely matched with target full-scale properties. Guide loads and relative motions between MRBC and hull were measured to obtain model-scale behavior. A wide range of sea states and towing speeds were covered in the test programs. Detailed comparison summarizing the statistical quantities of interests as well as time series and spectral plots are included in this paper. RAO and free decay comparisons are also described.
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dos Santos, Bruno Madella R., Guilherme E. Rueda, Fabio Tadao Matsumoto, Felipe C. R. Campos, Ana Paula Dos Santos Costa, and Kazuo Nishimoto. "Stability Analysis of a MPSO (Mono-Column Floater, Production, Storage and Offloading Unit): MonoBR." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92276.
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The MonoBR is a MPSO — mono-column floater, production, storage and offloading unit — a unique platform designed to handle steel catenary risers (SCR) in a depth of 1800 m in Gulf of Mexico oil fields whose target scenario is the ultra-deep water of the Walker Ridge. In this project, special concern was given to sea keeping behavior, constructability and security. Stability Analyses were carried out to ensure the system security and reliability. This paper describes the development carried out by The University of Sa˜o Paulo and PETROBRAS team, in order to analyze the main stability parameters of this new conceptual design for oil production and storage, the MonoBR. The main topics referred on the text are the damaged and intact stability analyses, the tank arrangement, wind influence, rules discussions, the AVCG (Allowable Vertical Center of Gravity) and damage compensation through ballast rearrangement.
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Yamazaki, Tetsuo, Daisuke Monoe, Tomoaki Oomi, Kisaburo Nakata, and Tomohiko Fukushima. "Application of Methane Supply Process Unit in Mass Balance Ecosystem Model Around Cold Seepage." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57498.
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Natural cold seepages are characterized as rapid upward transports of methane from deeper parts of geological structures to the seafloor. The original methane supply source is expected to locate below BSR (Bottom Simulating Reflector). The methane moved up to seafloor is mainly consumed by microorganisms living in anoxic marine sediments. When the methane supply is very large or rapid, remaining unconsumed methane escapes into the water column and is consumed by oxidizing bacteria. The supply mechanism of methane from the supply source to the cold seepages has not yet being clarified. In order to integrate the methane consumption processes in sediments and water column, a simple methane supply mechanism is developed.
Reports on the topic "Column unit"
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Fu, Yucheng, Jie Bao, Chao Wang, Rajesh Singh, Dushyant Barpaga, Richard Zheng, Zhijie Xu, et al. Absorber Column CFD model validation against PNNL’s device-scale absorber column on the LCFS unit. Office of Scientific and Technical Information (OSTI), July 2020. http://dx.doi.org/10.2172/1691502.
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Flach, G. SENSITIVITY ANALYSIS FOR SALTSTONE DISPOSAL UNIT COLUMN DEGRADATION ANALYSES. Office of Scientific and Technical Information (OSTI), October 2014. http://dx.doi.org/10.2172/1163502.
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KellerLynn, Katie. Redwood National and State Parks: Geologic resources inventory report. National Park Service, October 2021. http://dx.doi.org/10.36967/nrr-2287676.
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Comprehensive park management to fulfill the NPS mission requires an accurate inventory of the geologic features of a park unit, but Comprehensive park management to fulfill the NPS mission requires an accurate inventory of the geologic features of a park unit, but park managers may not have the needed information, geologic expertise, or means to complete such an undertaking; therefore, the Geologic Resources Inventory (GRI) provides information and resources to help park managers make decisions for visitor safety, planning and protection of infrastructure, and preservation of natural and cultural resources. Information in the GRI report may also be useful for interpretation. park managers may not have the needed information, geologic expertise, or means to complete such an undertaking; therefore, the Geologic Resources Inventory (GRI) provides information and resources to help park managers make decisions for visitor safety, planning and protection of infrastructure, and preservation of natural and cultural resources. Information in the GRI report may also be useful for interpretation. This report synthesizes discussions from a scoping meeting for Redwood National and State Parks (referred to as the “parks” throughout this report) held in 2004 and a follow-up conference call in 2019. Two GRI–compiled GIS data sets of the geology and geohazards of the parks are the principal deliverables of the GRI. The GRI GIS data are available on the GRI publications website http://go.nps.gov/gripubs and through the NPS Integrated Resource Management Applications (IRMA) portal https://irma.nps.gov/App/Portal/Home. Enter “GRI” as the search text and select a park from the unit list. Writing of this report was based on those data and the interpretations of the source map authors (see “GRI Products” and “Acknowledgements”). A geologic map poster illustrates the geology GRI GIS data set and serves as a primary figure for this GRI report. No poster was prepared for the geohazards GRI GIS data set. Additionally, figure 7 of this report illustrates the locations of the major geologic features in the parks. Unlike the poster, which is divided into a northern and southern portion to show detail while accommodating the parks’ length, figure 7 is a single-page, simplified map. The features labeled on figure 7 are discussed in the “Geologic History, Features, and Processes” chapter. To provide a context of geologic time, this report includes a geologic time scale (see "Geologic History, Features, and Processes"). The parks’ geologic story encompasses 200 million years, starting in the Jurassic Period. Following geologic practice, the time scale is set up like a stratigraphic column, with the oldest units at the bottom and the youngest units at the top. Organized in this manner, the geologic time scale table shows the relative ages of the rock units that underlie the parks and the unconsolidated deposits that lie at the surface. Reading the “Geologic Event” column in the table, from bottom to top, will provide a chronologic order of the parks’ geologic history. The time scale includes only the map units within the parks that also appear on the geologic map poster; that is, map units of the geohazards data are not included. Geology is a complex science with many specialized terms. This report provides definitions of geologic terms at first mention, typically in parentheses following the term. Geologic units in the GRI GIS data are referenced in this report using map unit symbols; for example, map unit KJfrc stands for the Cretaceous (K) and Jurassic (J) Franciscan Complex (f), Redwood Creek schist (rc), which underlies a portion of the Redwood Creek watershed (see “GRI Products”).
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Mueller, C., S. J. Piercey, M. G. Babechuk, and D. Copeland. Stratigraphy and lithogeochemistry of rocks from the Nugget Pond Deposit area, Baie Verte Peninsula, Newfoundland. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328989.
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Stratigraphic and lithogeochemical data were collected from selected drill core from the Nugget Pond gold deposit in the Betts Cove area, Newfoundland. The stratigraphy consists of a lower unit of basaltic rocks that are massive to pillowed (Mount Misery Formation). This is overlain by sedimentary rocks of the Scrape Point Formation that consist of lower unit of turbiditic siltstone and hematitic cherts/iron formations (the Nugget Pond member); the unit locally has a volcaniclastic rich-unit at its base and grades upwards into finer grained volcaniclastic/turbiditic rocks. This is capped by basaltic rocks of the Scrape Point Formation that contain pillowed and massive mafic flows that are distinctively plagioclase porphyritic to glomeroporphyritic. The mafic rocks of the Mount Misery Formation have island arc tholeiitic affinities, whereas Scrape Point Formation mafic rocks have normal mid-ocean ridge (N-MORB) to backarc basin basalt (BABB) affinities. One sample of the latter formation has a calc-alkalic affinity. All of these geochemical features are consistent with results and conclusions from previous workers in the area. Clastic sedimentary rocks and Fe-rich sedimentary rocks of the Scrape Point Formation have features consistent with derivation from local, juvenile sources (i.e., intra-basinal mafic rocks). The Scrape Point Formation sedimentary rocks with the highest Fe/Al ratios, inferred to have greatest amount of hydrothermally derived Fe, have positive Ce anomalies on Post-Archean Australian Shale (PAAS)-normalized trace element plots. These features are consistent with having formed via hydrothermal venting into an anoxic/ sub-oxic water column. Further work is needed to test whether these redox features are a localized feature (i.e., restricted basin) or a widespread feature of the late Cambrian-early Ordovician Iapetus Ocean, as well as to delineate the role that these Fe-rich sedimentary rocks have played in the localization of gold mineralization within the Nugget Pond deposit.
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Lahav, Ori, Albert Heber, and David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, March 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
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The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Graber, Ellen R., Linda S. Lee, and M. Borisover. An Inquiry into the Phenomenon of Enhanced Transport of Pesticides Caused by Effluents. United States Department of Agriculture, July 1995. http://dx.doi.org/10.32747/1995.7570559.bard.
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The objective of this collaborative research project was to determine the factors that may cause enhanced pesticide transport under effluent irrigation. For s-triazines, the potential for enhanced transport through association with effluent dissolved organic matter (OM) was shown to be small in batch and column studies and in numerical simulations. High alkalinity and pH of treated effluents increased soil-solution pH for selected soil-effluent combinations, promoting the dissolution of soil OM and mobilizing otherwise OM-retained pesticides. Evapotranspiration in column studies resulted in increased pore-water concentrations of dissolved OM and some pesticide transport enhancement with the greatest effect observed with OM-poor soils. For ionogenic pesticides, effluent-induced increases in soil-solution pH increased the mobility of pesticides with acid dissociation constants within 2 pH units of the initial soil-solution pH. Effluents high in suspended solids and/or monovalent cations resulted in blockage of soil pores reducing water-flow velocity and/or changing flow paths. Reduced flow resulted in an increase in desorption time of soil sorbed pesticides, increasing the amount available for further transport with the net effect being soil texture dependent. In terms of pesticide degradation in soils, effluents appeared to have only a minor effect for the few pesticides investigated.
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SIMPLIFIED MODELLING OF NOVEL NON-WELDED JOINTS FOR MODULAR STEEL BUILDINGS. The Hong Kong Institute of Steel Construction, December 2021. http://dx.doi.org/10.18057/ijasc.2021.17.4.10.
Full textAbstract:
Prefabricated modular steel (PFMS) construction is a more efficient and safe method of constructing a high-quality building with less waste material and labour dependency than traditional steel construction. It is indeed critical to have a precise and valuable intermodular joining system that allows for efficient load transfer, safe handling, and optimal use of modular units' strength. Thus, the purpose of this study was to develop joints using tension bolts and solid tenons welded into the gusset plate (GP). These joints ensured rigid and secure connectivity in both horizontal and vertical directions for the modular units. Using the three-dimensional (3D) finite element (FE) analysis software ABAQUS, the study investigated the nonlinear lateral structural performance of the joint and two-storey modular steel building (MSB). The solid element FE models of joints were then simplified by introducing connectors and beam elements to enhance computational efficiency. Numerous parameters indicated that column tenons were important in determining the joint's structural performance. Moreover, with a standard deviation (SD) of 0.025, the developed connectors and beam element models accurately predicted the structural behaviour of the joints. As a result of their simplification, these joints demonstrated effective load distribution, seismic performance, and ductility while reducing computational time, effort, and complexity. The validity of the FE analysis was then determined by comparing the results to the thirteen joint bending tests performed in the reference.