Gotowe bibliografie tematyczne / HORIZONTAL BED

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Gotowa bibliografia na temat „HORIZONTAL BED”

Autor: Grafiati

Data publikacji: 11 września 2023

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Artykuły w czasopismach na temat "HORIZONTAL BED"

Zhang, Zhenxiang, Jin Yang, Shengnan Chen, Qibin Ou, Yichi Zhang, Ximo Qu i Yafei Guo. "Numerical Simulation of Pulsed Gravel Packing Completion in Horizontal Wells". Energies 14, nr 2 (7.01.2021): 292. http://dx.doi.org/10.3390/en14020292.

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The gravel packing completion method for horizontal wells has the advantages of maintaining high oil production for a long time, maintaining wellbore stability, and preventing sand production, so it has become the preferred completion method for horizontal wells. At present, this technology still faces the problems of high sand bed height and poor gravel migration. In order to improve the efficiency of gravel packing in horizontal wells, pulsed gravel packing technology for horizontal wells is proposed for the first time. Based on the mechanism of hydraulic pulse, the Eulerian–Eulerian model, k-ε model based on the renormalization group theory (RNG k-ε model), and Fluent are used to simulate the solid-liquid two-phase flow. By optimizing the parameters such as frequency and amplitude of pulse waveform, the optimal pulse waveform of pulsed gravel packing in horizontal wells is determined. The effects of parameters such as sand-carrying fluid displacement, sand-carrying fluid viscosity, sand-carrying ratio, gravel particle size, and string eccentricity on pulsed gravel packing in horizontal wells are studied, and the distribution law of gravel migration velocity and volume fraction in horizontal wells is obtained. According to the results, it can be seen that with the increase of displacement and viscosity of carrier fluid, the volume fraction of fixed bed and moving bed decreases gradually, while that of suspension bed increases gradually. With the increase of sand-carrying ratio, gravel particle size, and string eccentricity, the volume fraction of fixed bed and moving bed increases gradually, while that of suspended bed decreases gradually. Comparing the effects of conventional gravel packing and pulsed gravel packing in horizontal wells, it can be concluded that the efficiency of pulsed gravel packing in horizontal wells is higher. The volume fraction of fixed bed and moving bed decreased by 30% and 40% respectively, while the volume fraction of suspended bed increased by 20%. The migration velocity of moving bed and suspended bed increased by 40% and 25%, respectively, and the migration ability of gravel improved obviously.

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Berni, C., H. Michallet i E. Barthélemy. "Effects of horizontal pressure gradients on bed destabilization under waves". Journal of Fluid Mechanics 812 (5.01.2017): 721–51. http://dx.doi.org/10.1017/jfm.2016.805.

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We report on new experiments designed to investigate bed destabilization processes in a two-dimensional wave flume physical model of a beach. The mobile bed consists of non-cohesive granular material of low density. The wave conditions are provided by repeating a cycle of waves made of two bichromatic groups of different period. The horizontal and vertical velocities are acoustically profiled vertically from free-stream elevation down to the still bed level in the surf zone. Additional measurements of the fluid pressure at positions closely aligned horizontally and vertically in and slightly above the sediment bed are undertaken. Mobile bed interfaces, still bed and top interface, are detected via acoustic and optical methods. Both methods are cross-compared and give similar results. Flow turbulence over the bed is analysed, the Reynolds turbulent shear stress is found negligible compared to the orbital flow induced momentum diffusion. The shear stress and the horizontal pressure gradient are computed at near-bed elevation and used in the bed incipient plug flow model of Sleath (Cont. Shelf Res., vol. 19 (13), 1999, pp. 1643–1664). Both the model and the measurements confirm that destabilization occurs when the non-dimensional pressure gradient (or Sleath number) exceeds the threshold value of 0.3 which is simultaneous with strong flow acceleration. The near-bottom fluid shear stress detected during these flow accelerations at steep wave fronts is found experimentally to be negative, which is retrieved with an unsteady plug flow model. This is suggesting that the fluid above the bed resists the sediment layer motion at these particular phases.

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Termini, Donatella. "Experimental Analysis of Horizontal Turbulence of Flow over Flat and Deformed Beds". Archives of Hydro-Engineering and Environmental Mechanics 62, nr 3-4 (1.12.2015): 77–99. http://dx.doi.org/10.1515/heem-2015-0021.

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AbstractLaboratory experiments in a straight flume were carried out to examine the evolution of large-scale horizontal turbulent structures under flat-bed and deformed-bed conditions. In this paper, the horizontal turbulence of flow under these conditions is analyzed and compared. The conditioned quadrant method is applied to verify the occurrence of turbulent events. The distributions of horizontal Reynolds shear stress and turbulent kinetic energy are also presented and discussed. Results show the occurrence of an “initial” sequence of horizontal vortices whose average spatial length scales with the channel width. Under deformed-bed conditions, this spatial length does not change.

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Woods, J. A., R. B. Thorpe i S. E. Johnson. "Horizontal pneumatic conveying from a fluidized bed". Chemical Engineering Science 63, nr 7 (kwiecień 2008): 1741–60. http://dx.doi.org/10.1016/j.ces.2007.11.040.

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Caws, Mary Ann. "On the Horizontal: Women Writing on Writing Women". PMLA/Publications of the Modern Language Association of America 122, nr 2 (marzec 2007): 549–57. http://dx.doi.org/10.1632/pmla.2007.122.2.549.

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Writing in bed: I have always loved Edith Wharton's habit of doing just that, as well as Cynthia Ozick's discussion of it (look how neat the desk at which Wharton is photographed in her stays; imagine how much more comfortable she is in bed with her stays undone). I remember learning, during my first studies of philosophy at Bryn Mawr, that René Descartes wrote in bed, by the heat of a stove supplied by Queen Christina, to say nothing of Winston Churchill's similar custom.

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Laishram, K., P. A. Kumar i T. T. Devi. "Effect of channel slope and roughness on hydraulic jump in open channel flow". IOP Conference Series: Earth and Environmental Science 958, nr 1 (1.12.2021): 012014. http://dx.doi.org/10.1088/1755-1315/958/1/012014.

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Abstract An experimental study is conducted on hydraulic jump characteristics for understanding the impact of slope in an open channel flume. Hydraulic jump on different channel characteristics (horizontal smooth & rough and sloping smooth & rough) were analysed. The measured characteristics of hydraulic jump with different channel roughness and different slope were compared. The results showed that the sequent depth ratio (y2/y1 ) increases with the increase in Froude number (Fr1 ) for smooth horizontal bed and horizontal rough bed. It was also observed that with an increase in Fr1 , a decrease in y2/y1 in smooth sloping bed condition and decreases for rough sloping bed. New empirical relationships were also developed with the experimental data and results were found similar with the observed hydraulic characteristics data.

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Lu, Zongyu, Baocheng Wu, Jiangang Shi, Chuanming Xi i Kai Wei. "A Multiparameter Coupled Prediction Model for Annular Cuttings Bed Height in Horizontal Wells". Geofluids 2022 (23.06.2022): 1–9. http://dx.doi.org/10.1155/2022/9938546.

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Cuttings accumulation in horizontal drilling is one of the main reasons for high drilling torque and drag and serious backing pressure and consequently influencing the rate of penetration (ROP), so inhibiting the generation of cuttings bed and keeping the hole clean is an important prerequisite to ensure the smooth and safe drilling of horizontal section. In order to master the formation mechanism of cuttings bed and reveal the influence law of influencing factors, based on the three-layer cuttings bed migration model and the two-phase solid-liquid flow theory, this paper establishes a numerical simulation method for cuttings migration characteristics in the annulus of horizontal wells, reveals the cuttings concentration distribution law and migration characteristics in the horizontal well section, and fits the engineering prediction model of cuttings bed height considering many factors such as geology, engineering, and fluid body according to the simulation results. The analysis of sensitive factors shows that the rate of penetrating, cuttings density, and drill pipe eccentricity is not conducive to borehole cleaning, and cuttings are easy to accumulate to form cuttings bed; increasing the drilling fluid density, displacement, and drill pipe speed is conducive to borehole cleaning and reducing the height of cuttings bed. The research shows that within the range of normal construction parameters, the error of the horizontal cuttings height prediction model is less than 10%, which can meet the needs of engineering analysis. The model provides convenience for engineering applications.

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Merazka, M., i M. S. Kim. "The Effect of a Ground Brace with a Spacer on the Displacement and Bearing Capacity of a Horizontally Loaded Single Pile". Russian Journal of Building Construction and Architecture, nr 3(59) (12.07.2023): 6–15. http://dx.doi.org/10.36622/vstu.2023.3.59.001.

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Statement of the problem. The influence of a ground brace with a spacer attached to the pile trunk on the movement and bearing capacity of piles under horizontal loads is investigated and the results obtained during the experiment are compared with the test results of a single pile. Results. A noticeable effect of the presence of a bed on the movement of the pile foundation has been established. With equal loads, piles with a bed have horizontal movement and the angle of rotation of the pile head is up to 2÷3 times less than those without a bed. An increase in the length of the strut leads to a decrease in the horizontal movement of the pile head up to 1.6 times and the angle of rotation up to 1.9 times compared to that with a bed, but without a strut. The bearing capacity of a pile with a bed increases up to 1.66 times with an increase in the length of the spacer from 0 to 3d, where d is the diameter of the cross-section of the pile. Conclusions. The dependence of the increase in the bearing capacity of the pile on the presence of a bed with a spacer was experimentally verified. The test results demonstrate a considerable ffect of the presence of a bed with a spacer on the horizontal and vertical movements of the pile, as well as on the decrease in the angle of rotation of the pile head.

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Tennakoon, S. G. K., L. Kondic i R. P. Behringer. "Onset of flow in a horizontally vibrated granular bed: Convection by horizontal shearing". Europhysics Letters (EPL) 45, nr 4 (15.02.1999): 470–75. http://dx.doi.org/10.1209/epl/i1999-00190-3.

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Rozprawy doktorskie na temat "HORIZONTAL BED"

Dewell, Elizabeth A. (Elizabeth Anderson) 1980. "Tilt bed testing of the subjective horizontal". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/69235.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaf 25).
Mittelstaedt (1987) suggested that inversion illusions which caused space sickness in astronauts was associated with a net headward bias in the body's gravireceptor organs, which could be measured on Earth using a tilting bed. Mittelstaedt showed that when individual subjects were asked to repeatedly position themselves to the gravireceptive subjective horizontal, individuals showed a small (<5 deg.) but consistent head up or head down bias that remained stable when retested weeks, months or even years later. A correlation with inversion illusion was noted in a small number of astronauts. The purpose of the present project was 1) to construct a new bed of slightly different design and 2) to verify Mittelstaedt's findings using a different subject population. Nine subjects each lay on their left side with their head immbobilized using a bite bar. They positioned the bed (and themselves) at the subjective horizontal ten successive times starting from standardized initial tilt angles which ranged from +/- 10 degrees. Tests were then repeated on right side. Four subjects returned a day later for retesting. Results showed that subjects repeatedly positioned themselves at their own subjective gravitational horizontal, which differed from true horizontal by several degrees a head down direction. Results of tests on the left and right side had similar means for most of the nine subjects; however 4 were statistically different. Left and right sides were combined, noting the above error. Mean biases in the subjective horizontal varied from -3.26 to -0.82 degrees head down between subjects, with overall mean -1.65 and s.d. 0.80. There was a statistically significant difference between responses of some subjects. Data from four subjects tested on both days was compared. A statistically significant correlation was not found, perhaps due to the small subject retest population. The differences between Mittelstaedt's data and present results are discussed.
by Elizabeth A. Dewell.
S.B.

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Rosenthal, G. N. "Lift forces on spherical particles near a horizontal bed in oscillatory flow". Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377239.

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Li, Fang. "Heat Transfer in a High-pressure Gas-solid Fluidized Bed with Horizontal Tube Bundle and Continuous Addition of Fines". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38002.

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Climate change is becoming more severe than ever in human history and the emission of green house gas urgently needs to be reduced while global energy consumption remains booming. Large-scale application of clean fossil fuel combustion shall be considered as a priority for its economical advantages as well as reliability in meeting global energy needs. Oxygen-fired pressurized fluidized bed combustor technology with downstream carbon capture and sequestration is considered a key approach to clean coal combustion. In such technology, the fluidized bed combustor operates at elevated pressures and houses an in-bed heat exchanger tube bundle. It is essential to understand the rate of heat transfer between the immersed heat exchange surface and the fluidized bed as it is a key parameter in heat exchanger design. The goal of this work was to investigate the impact of pressure and presence of fine particles (i.e., surrogate for pulverized fuel) on the overall tube-to-bed heat transfer coefficient. Experiments were conducted in a pilot-scale fluidized bed with an inner diameter of 0.15 m under cold flow conditions. A tube bundle consisting of five horizontal staggered rows was completely submerged in the bed. One of the tubes was replaced by a heating cartridge housed in a hollowed copper rod. Five thermocouples distributed at 45º intervals along the copper rod circumference measured the surface temperature and ensured that local effects were included. The bed material was large glass beads of 1.0 mm in diameter while the fines were glass beads of 60 µm in diameter and thus susceptible to entrainment. The fine particles were continuously fed to the fluidized bed and then captured downstream by a filter system. Fluidization was conducted at 101, 600 and 1200 kPa with excess gas velocities (Ug - Umf) of 0.21, 0.29 and 0.51 m/s. Fine particle feed rates were 0, 9.5 and 14.4 kg/h. Two heating rod positions (2nd row and 4th row) were studies. Overall, the heat transfer coefficient approximately doubled when pressure was increased from 101 to 1200 kPa. At atmospheric conditions, where the slug flow regime occurred, the maximum heat transfer coefficient was at the bottom of the rod, while it moved to the side of the rod at high pressures where the bubbling regime occurred. As the heating rod moving from 2nd row to the 4th row, the averaged heat transfer coefficient increased by respectively 18%, 9% and 6% at 101, 600 and 1200 kPa. The addition of fine particles decreased the average heat transfer coefficient by 10 to 20 W/m2 K where the time – averaged heat transfer coefficient was approximately 220 and 450 W/m2K at 101 kPa and 1200 kPa respectively. There was no effect on the angular profile across the tube surface. The results showed that average heat transfer coefficients matched the correlation developed by Molerus et al. (1995) within a 5% difference across all conditions when fines were not present.

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Chioukh, Nadji. "Wave effects on rigid and elastically-mounted horizontal circular cylinderd placed above a plane bed". Thesis, University of Manchester, 1995. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669701.

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Dornelas, Breno Almeida. "Análise experimental da tensão de cisalhamento mínima para suspensão de partículas em um leito horizontal". Universidade Federal do Espírito Santo, 2009. http://repositorio.ufes.br/handle/10/6248.

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Made available in DSpace on 2016-12-23T14:08:13Z (GMT). No. of bitstreams: 1 Breno Almeida Dornelas - parte 1.pdf: 376911 bytes, checksum: b45e88c007da3db1f74fa38428506e5c (MD5) Previous issue date: 2009-12-22
A remoção eficiente de cascalhos ainda é um desafio na perfuração de poços para produção de óleo e gás. O ponto crítico corresponde ao estágio horizontal da perfuração que intrinsecamente tende a formar um leito de partículas sedimentadas na parte inferior do poço em perfuração. A erosão desse leito de cascalhos oriundos do solo perfurado depende principalmente da tensão de cisalhamento promovida pelo escoamento do fluido de perfuração. Utilizando uma bancada experimental, composta de sistema para circulação de fluidos, caixa de cascalhos, unidade de bombeio e equipamentos de medição, investiga-se a tensão de cisalhamento mínima necessária para a erosão de um leito em função das propriedades do fluido e das partículas do leito. A área de observação consiste de uma caixa abaixo da linha de escoamento, para partículas calibradas de areia, em um duto de acrílico. Para as medições iniciam-se as bombas com baixa rotação e são feitos incrementos de freqüência. A cada patamar de freqüência são capturadas imagens de partículas carreadas pelo escoamento, registrando a vazão estabelecida. Com a análise do processamento das imagens define-se o momento em que o carreamento das partículas deixa de ser aleatório e esporádico e começa a ser permanente. A tensão de cisalhamento é determinada pela Correlação PKN (de Prandtl, von Kármán e Nikuradse) a partir da vazão mínima necessária para o arraste. Os resultados são obtidos para o escoamento de água e de solução águaglicerina
The efficient hole cleaning is still a challenge in the wellbore drilling for production of oil and gas. The critical point is the horizontal drilling that inherently tends to produce a bed of sediment particles at the bottom of the well. The erosion of this cuttings bed depends mainly on the shear stress promoted by the flow of drilling fluid. The shear stress required to drag cuttings bed is investigate according to the fluid and particles properties, using an experimental assembly, composed of a loop for circulation of fluids, of a particle box, of a pump system, camera and measuring equipment. The area of observation consists of a box below the line of flow, for calibrated sand particles, in an acrylic duct. The test starts with the pumps in low frequency and are made the increments. At each level of frequency are captured images of particles carried and it is records the established flow rate. The erosion criteria is defined when the drag particle no longer be random and sporadic, and begins to be permanent. The shear stress is determined by the PKN correlation (by Prandtl, von Kármán, and Nikuradse) from the minimum flow rate necessary to start the erosion process. Results were obtained for the flow of water; and of water and glycerin solution

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Rojas, Maria Lyda Bolaños. "Tratamento de fenol em reator anaeróbio horizontal de leito fixo (RAHLF) sob condições mesofílicas". Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-30012017-093926/.

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Um reator anaeróbio horizontal de leito fixo foi operado a escala de laboratório, visando verificar sua capacidade de degradação de fenol. O RAHLF foi construído em vidro de borosilicato com 100 cm de comprimento e 5,04 cm de diâmetro, preenchido com lodo anaeróbio imobilizado em matrizes de espuma de poliuretano. Prévio à realização do experimento o reator foi operado com substrato sintético, contendo como fontes de carbono glicose, ácido acético e ácido fórmico, atingida a estabilização da matéria orgânica para uma carga orgânica de 1028 mg/L, correspondente a uma remoção de DQO de 98%, foi iniciada a adição de fenol começando com uma concentração de 50 mg/L como única fonte de carbono. A concentração de fenol adicionada variou de 50 a 1200 mg/L e sua degradação foi avaliada através de determinação cromatográfica, utilizando cromatografia gasosa e parâmetros físico-químicos como pH, ácidos voláteis, alcalinidade e DQO. O RAHLF foi operado com um tempo de detenção hidráulica (TDH) de 12,3 horas. Com 50 mg/L, após 33 dias o reator atingiu uma remoção de fenol de 97%. Com 100 mg/L e depois de 148 dias de operação não foi detectado fenol no efluente do reator. Com 300 mg/L e após 58 dias de operação o reator apresentou 99% de remoção e uma concentração no efluente de 0,85 mg/L. Com 600 mg/L, 900 mg/L e 1200 mh/L, após 47, 29 e 7 dias de operação o reator alcançou remoções de 99%. Em todas as concentrações foi observado o predomínio de Methanosaeta, Methanobacterium e cocosmetanogênicos. Em relação à bactéria oxidadora de fenol foi observado o predomínio de coco-bacilos. As altas remoções de fenol observadas neste trabalho são devidas provavelmente à utilização de células imobilizadas.
A bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor was assayed aiming to verify its potential use for phenol degradation. The HAIB reactor consisted of a bore-silicate tube (100 cm long; 5.04 cm diameter) filled with polyurethane foam matrices containing immobilized anaerobic sludge. Before being subjected to phenol, the reactor was fed with synthetic substrate at the influent chemical oxygen demand (COD) of 1,028 mg/L achieving 98% of COD removal efficiency. Thereafter, phenol as the sole carbon source was added under step-increasing concentrations from 50 to 1,200 mg/L. Phenol degradation was evaluated by gas chromatographic analysis of influent and effiuent samples. Process monitoring included determinations of pH, volatile acids, alkalinity and COD. The HAIB reactor was operated at a constant hydraulic detention time (HDT) of 12,3 hours. After 33 days with 50 mg/L of phenol in the influent, the reactor achieved 97% of phenol removal efficiency. Successful phenol degradation (efficiency removal of 99%) occurred for influem concentrations of 100, 300, 600, 900 and 1,200 mg/L after 148, 58, 47, 29 and 7 days, respectively. The predominance of Methanosaeta, Methanobacterium and methanogenic cocci could be observed in all the operating conditions, besides the presence of phenol-oxidizing microorganisms as irregular rods. The results indicate that phenol degradation at very high rates can be accomplished in HAIB reactors containing acclimatized biomass.

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Prenzel, Marco [Verfasser]. "Scale-up of horizontal packed bed thermal energy storage units: An in-depth experimental and numerical investigation / Marco Prenzel". Düren : Shaker, 2021. http://d-nb.info/1233548050/34.

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Lima, Cláudio Antônio de Andrade. "Tratamento de esgoto sanitário em reator anaeróbio horizontal de leito fixo (RAHLF): escala piloto". Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-16052016-104721/.

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Este trabalho apresenta as avaliações de desempenho, das demandas operacionais e dos fatores intervenientes no aumento da escala da unidade piloto do Reator anaeróbio Horizontal de Leito Fixo (RAHLF) no tratamento de esgoto sanitário após passagem por peneira com malha de 1 mm, durante dois anos de operação. O reator dispunha de volume total de 237,5 1, construídos com tubos comerciais de PVC de 14,5 cm de diâmetro (D), dispostos em cinco módulos horizontais em série de 2,88 m, perfazendo um comprimento total de (L) de 14,4 m e relação de total de L/D de 100. O suporte de imobilização de biomassa, espuma de poliuretano em matrizes cúbicas de 1 cm de aresta, mostrou-se adequado ao desenvolvimento do biofilme. Em partida, sem inoculação prévia, ocorreu a sua consolidação a partir de 70 dias, com predominância de morfologia semelhante a Methanosaeta sp. em relação a da Methanosarcina. Em torno de 90 dias com afluente de 350 mg/l de DQO, observe-se a melhor qualidade do efluente, com valor de 100 mg/l de DQO. Em longa operação ocorreu queda de rendimento e menor reprodutibilidade das previsões do projeto, atribuída aos constantes entupimentos e ineficácia das operações de limpeza, com o comprometimento de volume reacional verificados por estudos de hidrodinâmica. Da investigação das origens dos equipamentos observou-se tratar mais de um efeito local e qualitativamente relacionado à biomassa retida que propriamente quantitativo e extensivo ao longo de todo reator, com produção continuada de polímeros extracelulares, promovendo um efeito sinérgico com os predominantes organismos filamentosos e com os sólidos particulados retidos no leito. Diante das potencialidades desta configuração de reator apontam-se alternativas de mitigação dos entupimentos e o direcionamento dos estudos necessários para novo aumento de escala para o tratamento de esgoto sanitário.
This work evaluated the performance, the operational demands and the intervenient factors in the scale-up of the horizontal flow anaerobic immobilized biomass (HAIB) reactor pilot unit, treating domestic sewage previously screened. The operation was monitored for two years. The five- module (2.88 m length each) reactor volume was 237.5 liters and it was built with commercial PVC pipes of 14.5 cm of diameter (D), resulting in a total length (L) of 14.4 m and in a total ratio L/D of approximately 100. The immobilization support, cubic matrices of polyurethane foam (1 cm edge), showed to be suitable for the anaerobic biofilm development. During the start-up, without previous inoculation, the biofilm seemed to be consolidated after 70 days, and Methanosaeta sp. morphology predominated, in detriment of Methanosarcina. With an affluent of 350 mg COD/L, the best reactor performance was observed in about 90 days of operation (100 mg COD/L in the effluent). However, with the continuous operation, its performance decreased and the project predictions did not seem to fit anymore. These facts were probably due to the frequent cloggings ant the inefficiency of the backwashing procedures, leading to a decreasing of the operational volume. The origin of the clogging seemed to be related to the extracellular polymer production, linked to a synergic effect with the filamentous organisms and the particulate solids in the bed. Despite these operational problems, there were found alternatives to mitigate the clogging, and studies about a new scale-up methodology, in order to treat domestic sewage, were strongly recommended.

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Chen, Kaicheng [Verfasser], i Evangelos [Gutachter] Tsotsas. "Modeling and validation of particle drying and coating in a continuously operated horizontal fluidized bed / Kaicheng Chen ; Gutachter: Evangelos Tsotsas". Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1219937258/34.

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Chen, Kaicheng Verfasser], i Evangelos [Gutachter] [Tsotsas. "Modeling and validation of particle drying and coating in a continuously operated horizontal fluidized bed / Kaicheng Chen ; Gutachter: Evangelos Tsotsas". Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1219937258/34.

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Książki na temat "HORIZONTAL BED"

Sandler, H. Joint U.S./U.S.S.R. study: comparison of effects of horizontal and head-down bed rest. Moffett Field, Calif: Ames Research Center, 1990.

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I, Grigorʹev A., i Ames Research Center, red. Joint U.S./U.S.S.R. study: Comparison of effects of horizontal and head-down bed rest. Washington, D.C: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, 1990.

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Cheel, R. J. Horizontal lamination and the sequence of bed phases and stratification under upper flow regime conditions. s.l: [Brock University], 1990.

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Chioukh, N. Wave effects on rigid and elastically-mounted horizontal circular cylinderd placed above a plane bed. Manchester: UMIST, 1995.

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Somaini, Dario R. Erdbebenverhalten schwimmend gelagerter Balkenbrücken bei Berücksichtigung der Boden — Struktur — Interaktion und der horizontal wandernden Wellen. Basel: Birkhäuser Basel, 1985. http://dx.doi.org/10.1007/978-3-0348-5174-9.

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Somaini, Dario r. Dr. Erdbebenverhalten schwimmend gelagerter Balkenbrucken bei Berucksichtigung der Boden-Struktur-Interaktion und der horizontal wandernden Wellen. Basel: Birkhauser Verlag, 1985.

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Eberle, Jens Christian. Zum initialen Einfluss einer reversibel veränderten Vertikaldimension bei Totalprothesenträgern auf die horizontale Projektion des Körperschwerpunktes. Marburg: Philipps-Universität Marburg, 2011.

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Frischmuth, Barbara. Im Liegen ist der Horizont immer so weit weg: Grenzüberschreitungen bei Barbara Frischmuth. Wien: Sonderzahl, 2016.

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Bormann, Franz-Josef. Natur als Horizont sittlicher Praxis: Zur handlungstheoretischen Interpretation der Lehre vom natürlichen Sittengesetz bei Thomas von Aquin. Stuttgart: Verlag W. Kohlhammer, 1999.

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Więcej źródeł

Części książek na temat "HORIZONTAL BED"

Lit, Q. H., Y. G. Zhang i A. H. Meng. "Design and Application of Novel Horizontal Circulating Fluidized Bed Boiler". W Proceedings of the 20th International Conference on Fluidized Bed Combustion, 206–11. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02682-9_27.

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Asegehegn, Teklay Weldeabzgi, i Hans Joachim Krantz. "Hydrodynamic Simulation of Gas-Solid Bubbling Fluidized Bed Containing Horizontal Tubes". W Proceedings of the 20th International Conference on Fluidized Bed Combustion, 864–69. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02682-9_134.

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Zhang, Kai, ZongSheng Zhao i YuXiang Huo. "Formation Mechanism and Migration Law of Cuttings Bed in Horizontal Directional Drilling". W Lecture Notes in Civil Engineering, 77–90. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-4067-5_8.

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Lu, P., R. Zhang, J. Pu, C. S. Bo i W. P. Pan. "Experimental Study on Mass and Heat Transfer Characteristics in a Horizontal Circulating Divisional Fluidized Bed". W Proceedings of the 20th International Conference on Fluidized Bed Combustion, 379–85. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02682-9_56.

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Aihong, Meng, Li Qinghai, Zhang Yanguo, Wang Zhaojun i Dang Wenda. "Experimental Investigation on a 0.35 MWth Coal-Fired Horizontal Circulating Fluidized Bed Boiler". W Cleaner Combustion and Sustainable World, 651–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-30445-3_90.

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Murphy, Clodagh, i David Cooper. "The Evolution of Horizontal Subsurface Flow Reed Bed Design for Tertiary Treatment of Sewage Effluents in the UK". W Water and Nutrient Management in Natural and Constructed Wetlands, 103–19. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9585-5_9.

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Lv, Yu-min, Xue-shen Zhu, Guangshan Guo, Cun-wu Wang i Jiangong Zhang. "Study on the Mechanism of a Multi-branch Horizontal Well in Enhancing the Production Performance of Coal-Bed Methane Reservoirs in the SY Block, Qinshui Basin". W Springer Series in Geomechanics and Geoengineering, 3027–39. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0761-5_283.

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Loos-Hilgert, Vera, i Erhard Wedekind. "Mehrgenerationale Bindungsdynamik in der systemischen Paartherapie – Bindungsmuster und aff ektive Kommunikation bei Paaren". W Systemische Horizonte, 179–86. Göttingen: Vandenhoeck & Ruprecht, 2011. http://dx.doi.org/10.13109/9783666404382.179.

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Ollefs, Barbara. "Stärkung der elterlichen Präsenz im Modell des gewaltlosen Widerstandes in der Diabetesbetreuung bei Kindern und Jugendlichen". W Systemische Horizonte, 145–54. Göttingen: Vandenhoeck & Ruprecht, 2011. http://dx.doi.org/10.13109/9783666404382.145.

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Schmidt, Olaf. "Horizontaler Gentransfer bei Bakterien". W Genetik und Molekularbiologie, 175–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-50274-7_10.

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Streszczenia konferencji na temat "HORIZONTAL BED"

Walle´n, Vesa V. "Horizontal Pressure Fluctuation in Bubbling Fluidized Bed". W 17th International Conference on Fluidized Bed Combustion. ASMEDC, 2003. http://dx.doi.org/10.1115/fbc2003-046.

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Pressure measurements were conducted in a two-dimensional hot atmospheric bubbling fluidized bed reactor in the laboratory of Energy and Process Engineering at Tampere University of Technology. A set of six fast pressure transducers was used to detect the rapid pressure fluctuations inside the bubbling bed of the reactor. These pressure transducers were placed both vertically and horizontally into the reactor. From these measurements it was found that the vertical pressure fluctuation took place at the same time at different levels of the bed. Also the same fluctuation could be seen under the air distributor. The horizontal pressure fluctuation was found to vary both by place and time. At the bottom part of the bed the highest pressure peaks was found at centre of the bed. Most of the time there was a pressure gradient the highest pressure being in the centre of the bed. This gradient creates horizontal flow of gases from middle to the sides. The velocity of this flow varies with the size of the pressure gradient. The opposite effect can be found in the upper part of the bed. The highest pressure was no more in the middle part of the bed. Instead, it was found to be between the centre of the bed and left and right walls. The pressure was low at the walls but also rather low at the middle of the bed. There must be flow towards the walls and to the centre axis. These pressure fluctuations can provide an explanation for the well-known “wandering plume” effect. They can also give a tool to better describe the mixing inside a bubbling fluidized bed. This kind of tool is needed when biomass combustion is modelled in bubbling fluidized bed.

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Pedrosa, Camilo, Bjørnar Lund, Jan David Ytrehus, Nils Opedal i Arild Saasen. "Experimental Bench-Scale Study on Cuttings-Bed Erosion in Horizontal Wells". W ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-78266.

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Abstract Cuttings-beds formation while drilling wellbores is a common challenge, especially for horizontal wells, as drilled particles have higher area to be deposited and form cuttings-beds, which can cause several problems such as, increased torque and drag, pipe sticking or pipe breakage, among others. Removal of the drilled-cuttings is done by circulating a suitable drilling fluid through the wellbore. This paper presents results from laboratory tests with deposited cuttings-bed and the flow of a fluid to erode the bed. The simulated cuttings-bed is a 1m long deposited sand-bed in a horizontal section. Three different types of fluids are being used in the tests. To investigate how the rheological properties can affect the erodibility of the cuttings-bed, water (as a Newtonian fluid), a xanthan gum solution and a water-based drilling fluid prepared for an offshore field operation (as a non-Newtonian fluids) are applied. Ultrasound measurements together with differential bed weight have been used to analyze the fluid-bed interaction. Results have shown that the cuttings-bed is eroded by dune movement. Saltation and dragging of sand particles due to the fluid flow appear to create a crest and then avalanche them down. The different types of fluids undergo different shear rates from the same pump power as the viscosity changes, as well as flow rates dependency along the dune extent.

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Cole, Tanya G., Linda Shackelford, Chris A. Miller i J. Fernando Figueroa. "Instrumentation of Horizontal Exercise Machine". W ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0004.

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Abstract Bed rest studies provide an opportunity to conduct ground-based studies of the physiological changes which occur on orbit. Astronauts are known to lose muscle and bone mass during space flights, and effective countermeasures are being sought. The muscle loss is extensive, even for short duration missions, but it is fairly easily regained upon return to the earth’s gravity. Bone loss, on the other hand, is a slower process. The effects are long lasting, and significant loss from a long duration mission may cause fracture when the body is subjected to the sometimes rigorous forces of gravitational environments. For this reason, studies are being done at NASA’s Johnson Space Center Bone and Mineral Physiology Laboratory on heavy resistive exercises that decrease or prevent loss of bone mineral density (BMD) in bed rest subjects.

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Batson, Christina A., Stephanie M. Horne, Mandy E. Poe, Ryan Butts, Lauren Graffeo, Beth A. Todd i Linda C. Shackelford. "Exercises to Maximize Stress in Bones During Bed Rest Studies". W ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0002.

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Abstract Bone Mineral Density (BMD) loss seen in astronauts can be simulated on Earth by prolonged horizontal bed rest. A device known as the Horizontal Exercise Machine (HEM) has been designed to test the effectiveness of heavy resistive exercise regimens for bed rest subjects. The objective of this project is to estimate the mechanical stress on the skeletal system due to various types of exercises and determine which exercises will best prevent BMD loss. The stress will be calculated at skeletal locations of most concern during long-duration space flight.

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Raihane, A., O. Bonnefoy, J. L. Gelet, J. M. Chaix, G. Thomas, Albert Co, Gary L. Leal, Ralph H. Colby i A. Jeffrey Giacomin. "Densification of a 3D Granular Bed by Horizontal Vibrations". W THE XV INTERNATIONAL CONGRESS ON RHEOLOGY: The Society of Rheology 80th Annual Meeting. AIP, 2008. http://dx.doi.org/10.1063/1.2964898.

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Stephen, R. A., i C. H. Cheng. "Synthetic acoustic logs over bed boundaries and horizontal fissures". W SEG Technical Program Expanded Abstracts 1986. Society of Exploration Geophysicists, 1986. http://dx.doi.org/10.1190/1.1893143.

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Ji, Guodong, Haige Wang, Hongchun Huang, Meng Cui, Feixue Yulong, Ying Ma i Xiaofeng Sun. "Achieving Improved Drilling Performance with Hole Cleaning Technology in Horizontal Shale Gas Wells in Sichuan Basin of China". W International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21214-ms.

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Abstract The horizontal section length of shale gas horizontal wells in Sichuan Basin in the south-west of China generally exceeds 2000m. Cuttings are apt to accumulate and form cuttings beds along such long and curve horizontal sections due to low cuttings carrying capacity, which often results in excessive torque and drag or even stuck pipes during drilling process. According to the statistics dada inthe period of Jan. - Oct. 2019, more than 25 stuck pipe incidents and 15 rotary steering tools loss in borehole were reported due to inefficient cuttings transportation in the long horizontal wells in Sichuan Basin. This paper studies the cuttings transportation and cuttings bed formation in horizontal wells. A prediction model for the distribution of cuttings bed was established. A monitoring and analysis software for the cuttings bed and cuttings cleaner with V-shaped spiral blades that is used to agitate the cuttings bed wasdeveloped. The software calculates the distribution and thickness of the cuttings bed according to the well trajectory, wellbore structure, drilling fluid characteristics, etc., and provides the optimal operating parameters for the removal of the cuttings bed by the rotating and reciprocating drill string. Then, the drill cuttings remover in the drill string moves to the predicted position of the drill cuttings, scrapes the drill cuttings and creates a swirling flow during the pipe rotation. The combined application of software and makeup remover can effectively solve the issue of borehole cleaning in long horizontal wells. One of the field applications was carried out in the well Ning 209H12, a shale gas horizontal well in Sichuan Basin. The well experienced excessive torque and drag issue during the tripping of drill string of long horizontal section. Thesoftware ran based on oil well data, and it determines the placement and thickness of cuttings beds in the well and calculates the optimal operating parameters for a flow rate of about 32L/s and a speed of 100rpm to remove them. By rotatingand reciprocating the drill string with recommended operating parameters along the cuttings bed interval, the removers helped cleaning the cuttings bed efficiently and significant amount of cuttings was observed at vibration screen. After cleaning the cuttings bed interval, the trip smoothly ran to the bottom without any excessive torque and drag, and then continues to drill in cooperation with the removers to the total depth. During the well completion, there was no problem with the operation of electrical logging and production casing. This cuttings removal technology has been used in other shale gas formations and tight gas formations where horizontal wells are widely used.

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Elgaddafi, Rida, Ramadan Ahmed, Hamidreza Karami, Mustafa Nasser i Ibnelwaleed Hussein. "Mechanistic Modeling of Wellbore Cleanout in Horizontal and Inclined Wells". W SPE/ICoTA Well Intervention Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204442-ms.

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Abstract The accumulation of rock cuttings, proppant, and other solid debris in the wellbore due to inadequate cleanout remarkably impedes field operations. This article presents a new hole cleaning model, which calculates the Critical Transport Velocity (CTV) in conventional and fibrous fluids. The study is aimed to establish an accurate mechanistic model for optimizing wellbore cleanout in horizontal and inclined wells. The new CTV model is established to predict the initiation of bed particle movement during cleanout operations. The model is formulated considering the impact of fiber using a special drag coefficient (i.e. fiber drag coefficient), which represents the mechanical and hydrodynamic actions of suspended fiber particles and their network. The dominant forces acting on a single bed particle are considered to develop the model. Furthermore, to enhance the precision of the model, recently developed hydraulic correlations are employed to compute the average bed shear stress, which is required to determine the CTV. In horizontal and highly deviated wells, the wellbore geometry is often eccentric, resulting in the formation of flow stagnant zones that are difficult to clean. The bed shear stress in these zones is sensitive to the bed thickness. The existing wellbore cleanout models do not account for the variation in bed shear stress. Thus, their accuracy is limited when stagnant zones are formed. The new model addresses this problem by incorporating hydraulic correlations to account for bed shear stress variation with bed height. The accuracy of the new model is validated with published measurements and compared with the precision of an existing model. The use of fiber drag and bed shear stress correlations has improved model accuracy and aided in capturing the contribution of fiber in improving wellbore cleanout. As a result, for fibrous and conventional fluids, the predictions of the new model have demonstrated good agreement with experimental measurements and provided better predictions than the existing model. Model predictions show a noticeable reduction in fluid circulation rate due to the addition of a small quantity of fiber (0.04% w/w) in the fluid. In addition, results show that the existing model over predicts the cleaning performance of both conventional and fibrous fluids.

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Du, J., A. Bück i E. Tsotsas. "Investigation of spray agglomeration process in continuously operated horizontal fluidized bed". W 21st International Drying Symposium. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.7809.

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Spray fluidized bed agglomeration is an important process in particle formation and is widely used in the chemical, pharmaceutical and food industry. In this study a continuously operated horizontal fluidized bed is employed to obtain a continuous agglomeration process. It is conducted with glass beads (dst=200 µm) and water-based binder hydroxy-propyl-methyl-cellulose (HPMC) sprayed by three top nozzles. The steady state is reached and samples are taken periodically and analyzed. The influence of fluidization air temperature and configurations of internal weirs are studied. Keywords: horizontal fluidized bed, spray agglomeration, continuous process

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Ignatenko, Yaroslav, Oleg Bocharov, Andrey Gavrilov i Roland May. "Steady-State Cuttings Transport Simulation in Horizontal Borehole Annulus". W ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77266.

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The paper presents the results of modeling the steady-state flow of drilling fluid with cuttings in an annulus for the flow regimes typical for horizontal drilling. The studied parameters include effects like fluid rheology, drillstring rotation and eccentricity on flow regime, pressure drop and cuttings bed. It has been demonstrated that increasing the drilling fluid’s effective viscosity increases the pressure drop, but it decreases the cuttings bed area, while drillstring rotation significantly changes the flow structure, improving cuttings transport and reducing the pressure drop. The considered flow structure can change abruptly due to changed drill string positioning and rheological fluid properties. Such structural changes are followed by abrupt changes in the pressure drop and cuttings bed area.

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Raporty organizacyjne na temat "HORIZONTAL BED"

Budzich, Jeffrey. PR-685-184506-R07 Scour Equations and Field Verification Methods. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), luty 2022. http://dx.doi.org/10.55274/r0012210.

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Channel hydrology, hydraulics, and sediment composition are key variables to calculate vertical and horizontal channel movement. There are a variety of published methods available for estimating channel bed scour that were highlighted in the PRCI Phase A1 report. This report seeks to further the understanding of these methods by comparing computed scour derived from the published methods to actual measured observations in the field. Depth measurements were collected across a transect(s) at six study locations during a variety of flows over the 19-month study period (March 2020 through September 2021) to evaluate scour.

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Budzich, Jeffrey. PR-685-184506-R05 Fluvial Geomorphology Equations and Mechanics. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), kwiecień 2020. http://dx.doi.org/10.55274/r0011666.

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Channel hydrology, hydraulics, and sediment composition are key variables to calculating vertical and horizontal channel movement. A variety of methods are available for estimating channel bed scour, bank erosion, and channel migration with fewer available to predict avulsion potential. These methods vary in complexity from simplified empirical and theoretical equations to complex multi-dimensional models that may be used to understand potential hydrotechnical threats to pipelines and other structures. Furthermore, there are a variety of publicly available resources of relevant information to enhance pipeline operators' development and implementation of an effective water crossing program. The public resources include the United States Geological Survey, the National Weather Service within the National Oceanic and Atmospheric Administration, Federal Emergency Management Administration, United States Department of Agriculture, Natural Resource Conservation Service, and the Government of Canada.

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Sakaguchi, T., S. Hosokawa i Y. Fujii. Flooding characteristics of gas-liquid two-phase flow in a horizontal U bend pipe. Office of Scientific and Technical Information (OSTI), wrzesień 1995. http://dx.doi.org/10.2172/107025.

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Glick, Mark, Gabriel A. Lozada, Pavitra Govindan i Darren Bush. The Horizontal Merger Efficiency Fallacy. Institute for New Economic Thinking Working Paper Series, sierpień 2023. http://dx.doi.org/10.36687/inetwp212.

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The Department of Justice and Federal Trade Commission Merger Guidelines (the “Merger Guidelines”), including the much improved latest revision in 2023 (the “New Merger Guidelines”), have continued to perpetrate what we call in this paper the horizontal merger efficiency fallacy. The fallacy arises because in the Guidelines the term “efficiencies” has become unmoored from its foundations in economic theory and has been reduced to the business school construct of cost savings. We show that cost savings can only be considered universally socially beneficial by acceptance of what is termed “the Consumer Welfare Standard” (antitrust) or “the surplus theory of welfare” (economics), a theory that has been discredited and abandoned by welfare economists. In economic theory, efficiency means Pareto Efficiency. We explore the various attempts to tether the cost savings definition of efficiency to Pareto Efficiency and explain why these attempts have failed. We conclude that there is no sound way to theoretically reconcile cost savings with the economic meaning of efficiencies. We then move beyond the efficiency fallacy and show how modern welfare economics can be used to integrate Congressional antitrust goals into the New Merger Guidelines. This requires abandoning the unsupported “standard deduction” for efficiencies and replacing it with an evidence-based assessment of how a specific merger under review potentially impacts Congressional antitrust goals. This change renders the present efficiency rebuttal section of the New Merger Guidelines superfluous, and we provide specific reasons why this section as currently drafted is flawed and should be jettisoned.

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Author, Unknown. L52287 Pre-Construction Drillability Assessment for Horizontal Directional Drilling in Rock. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), sierpień 2008. http://dx.doi.org/10.55274/r0011760.

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Construction contractors often claim extra compensation associated with horizontally directionally drilled (HDD) pipeline installations is needed when drilling in rock. These claims result from HDD contractors' allegations that rock properties experienced during construction are significantly different from the properties on which the contractors' bids were based. This report provides information and recommendations that improve exploration and testing methods for assessing the drillability of rock to be encountered on HDD pipeline installations. These improvements will lead to a better understanding of rock drillability which will in turn lead to more accurate bid prices and more effective drilling plans. Pipeline installation costs will be reduced by reducing claims for extra work, improving contractor efficiency, and decreasing risk associated with HDD installations in rock. This report also addresses contractual considerations and alternate dispute resolution.

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Honegger, Wijewickreme i Monroy. L52325 Assessment of Geosynthetic Fabrics to Reduce Soil Loads on Buried Pipelines - Phase I and II. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), grudzień 2011. http://dx.doi.org/10.55274/r0010398.

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High soil loads on buried pipelines can lead to unacceptably high pipeline strains developed in response to permanent ground displacement. Common causes of permanent ground displacement are related to slope instability as a result of heavy precipitation or ground subsidence. In addition, several permanent ground displacement hazards are related to earthquakes including surface fault displacement, triggered landslide movement, surface ground settlement related to liquefaction, and lateral spread displacement. Result: Four specific areas of investigation were completed: 1.Performed baseline tests in moist sand to confirm minimal difference in horizontal soil restraint between moist and dry sand. 2.Performed tests to gauge the variation in horizontal load reduction with separation between the pipe and an inclined trench wall lined with two layers of geotextile. 3.Performed tests in compacted 19 mm (0.75 in) minus sand and crushed limestone (referred to locally in British Columbia as road mulch) to attempt to provide larger difference between horizontal forces developed with and without lining a trench wall with geotextile. 4.Performed tests to attempt to confirm oblique horizontal-axial soil restraint behavior reported in small-scale tests and centrifuge tests. Benefit: Rather than undertake further physical testing to better understand how the presence of single or dual layers of geotextile fabric changes the mechanisms by which soil restraint develops for horizontal ground displacement, future efforts should focus on numerical simulation preferably using discrete element methods. Until full-scale test data are available to confirm consistent prediction of oblique horizontal-axial soil restraint, the practice of treating horizontal and axial soil springs independently in the analysis of buried pipeline response to ground displacement, as is the current practice, should be maintained.

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Marlow, Thomas, Laurie Perry (Archived) i Carrie Greaney. PR-000-18COMP-R05 Horizontal Directional Drilling Compendium. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), styczeń 2019. http://dx.doi.org/10.55274/r0011550.

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The PRCI Technical Committees have carried many research projects related to the subject of horizontal directional drilling (HDD). This report; therefore, presents a summary of past PRCI-funded studies in the area of HDD. Since studies sponsored by other industry groups (e.g., INGAA, EPRG, APIA, CEPA, etc.) or by individual pipeline companies are not included, this report does not represent a review of the topic in the broader industry-wide sense. Instead, it is designed to provide a guide to past work so that current TC members can identify and locate project reports that might be of use in addressing their current day-to-day HDD issues.

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Montalvo-Bartolomei, Axel, Bryant Robbins, Erica Medley i Benjamin Breland. Backward erosion testing : Magnolia Levee. Engineer Research and Development Center (U.S.), wrzesień 2021. http://dx.doi.org/10.21079/11681/42140.

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Using a confined flume device, an experimental study investigated the critical horizontal gradient of soils obtained from a site identified as potentially vulnerable to backward erosion piping (BEP). Tests were conducted on glacial outwash material obtained from a sand and gravel quarry in the vicinity of Magnolia Levee in the community of Magnolia, OH. The two bulk samples collected from the quarry had similar grain-size distributions, grain roundness, and depositional environments as the foundation materials beneath the levee. Samples were prepared at various densities and subjected to gradual increases of flow in a wooden flume with an acrylic top until BEP was observed. The critical average horizontal gradient ranged from 0.21 to 0.30 for a bulk sample with a coefficient of uniformity of 1.6, while tests conducted on a bulk sample with a coefficient of uniformity of 2.5 yielded critical average horizontal gradients of 0.31 to 0.36. The critical average gradients measured during these tests compared favorably to values in the literature after applying adjustments according to Schmertmann’s method.

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Bhagavathula, Rajaram, Ronald Gibbons i Andrew Kassing. Roadway Lighting’s Effect on Pedestrian Safety at Intersection and Midblock Crosswalks. Illinois Center for Transportation, sierpień 2021. http://dx.doi.org/10.36501/0197-9191/21-028.

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This study evaluates the visual performance of four intersection lighting designs and five midblock crosswalk lighting designs along with two pedestrian safety countermeasures (rectangular rapid flashing beacons and flashing signs) at three light levels. The study involved a pedestrian detection task, which was completed at night on a realistic roadway intersection and a midblock crosswalk. The results from the study showed that driver nighttime visual performance at intersection and midblock crosswalks was influenced by the lighting design and light level. Intersections should be illuminated to an average horizontal illuminance of 14 lux (1.3 fc). This light level ensures optimal visibility of pedestrians regardless of the lighting design (or luminaire layout) of the intersection. The average horizontal illuminance of 14 lux (1.3 fc) also increases the visibility of pedestrians when glare from oncoming vehicles is present. The 14 lux (1.3 fc) average horizontal illuminance is valid for all lighting designs evaluated except the lighting design that illuminated the exits of the intersection. When the exits of the intersection are illuminated, an average horizontal illuminance of 24 lux (2.2 fc) is needed to offset the disability glare from opposing vehicles. Midblock crosswalks should be illuminated to an average vertical illuminance of 10 lux (0.9 fc) to ensure optimal pedestrian visibility. Where overhead lighting is available, midblock crosswalk lighting designs that render the pedestrian in positive contrast are recommended. Where overhead lighting is not available, crosswalk illuminators can be used to illuminate midblock crosswalks. At night, pedestrian crossing treatments such as rectangular rapid flashing beacons and flashing signs should not be used for pedestrian visibility at midblock crosswalks. Pedestrians crossing treatments should be used in conjunction with overhead lighting or crosswalk illuminators at the established vertical illuminance to ensure optimal pedestrian visibility at midblock crosswalks.

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Zhang. L52052 Control of Horizontal Beam Width with Phased Array Transducers. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), styczeń 2008. http://dx.doi.org/10.55274/r0010945.

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Accurate defect sizing is becoming more and more critical in pipeline welds due to the application of Engineering Critical Assessment, demanding deep sea applications, the arrival of high performance piping, and increased public safety demands. This project improved horizontal beam focusing for automated ultrasonic testing; curved arrays, focused lenses and electronic focusing using phased arrays were investigated. Two target applications were selected: thickwalled risers and tendons, and thinner walled high performance pipes for onshore. Extensive computer modeling was performed to optimize the focusing. The recommended array for thick-walled pipes has 360 elements in three rows, and is mechanically curved. The results from this 1.5D and a standard 1D array on a thick-wall calibration block showed that the 1.5D array had significantly better sizing. Also important, side lobes were significantly reduced. Computer modeling showed that a 60 element, 1 mm pitch array with a 100 mm curvature gave significant improvements over the standard unfocused array. The experimental results showed a significant improvement; the curved array oversized FBH reflectors by only ~1 mm, instead of the 4�6 mm from the unfocused array. These curved arrays can be used on PipeWIZARD with no modifications to the general mechanics or software.

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