CFD Simulations of Gas Fluidized Beds Using Alternative Eulerian-Eulerian Modelling Approaches

2002 ◽  
Vol 1 (1) ◽  
Author(s):  
Paola Lettieri ◽  
Luca Cammarata ◽  
Giorgio D. M. Micale ◽  
John Yates
Keyword(s):  
Kinetic Model ◽  
Fluidized Beds ◽  
Numerical Procedure ◽  
Commercial Code ◽  
Fluid Bed ◽  
Group A ◽  
Gas Fluidized Beds ◽  
Group B ◽  
Particle Bed ◽  
First Time

A commercially available Computational Fluid-Dynamics code, CFX-4, has been chosen to carry out computer simulations of gas fluidized beds. In this study, the Eulerian-Eulerian granular kinetic model, which is a standard option of the code, has been used. Fluid-bed simulations of Geldart Group B materials have been performed using the granular kinetic model, spanning three hydrodynamic regimes: bubbling, slugging and turbulent fluidization. Furthermore, an alternative Eulerian-Eulerian model, the so-called "particle-bed model", has been implemented for the first time within a commercial code, and results are presented from simulations of the bubbling and slugging fluidization of a Geldart Group B material, and for the homogeneous fluidization of a Group A material. A numerical procedure has been developed to allow for a tight control of the fluid-bed voidage at maximum packing during the simulations with the particle-bed model. Results show that both the granular kinetic model approach and the particle-bed model are able to describe significant aspects of the investigated fluidization regimes.

2D and 3D CFD Simulations of Bubbling Fluidized Beds Using Eulerian-Eulerian Models

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Luca Cammarata ◽  
Paola Lettieri ◽  
Giorgio D. M. Micale ◽  
Derek Colman
Keyword(s):  
Kinetic Model ◽  
Bubble Size ◽  
Fluidized Beds ◽  
Numerical Procedure ◽  
Cfd Simulations ◽  
3D Simulations ◽  
Gas Fluidized Beds ◽  
Group B ◽  
Particle Bed ◽  
2D And 3D

This paper reports on CFD simulations of freely bubbling gas fluidized beds using CFX-4, a commercial code developed by CFX Ltd. (formerly AEA Technology). Two Eulerian-Eulerian modelling approaches, the granular kinetic model and the particle-bed model (Gibilaro, 2001), have been investigated. The particle bed model has been recently implemented in CFX-4 for 2D simulations and a numerical procedure was developed to allow for a tight control of the fluid-bed voidage at maximum packing during the simulations, see Lettieri et al. (2003). The work has now been extended to 3D simulations and qualitative and quantitative results are presented in this paper for both the 2D and 3D simulations of the bubbling fluidization of a Geldart Group B material. Results on bed expansion, bubble size and bubble hold-up are reported. In particular, simulated bubble size is compared with predictions given by the Darton et al. (1977) equation at different bed heights. The paper shows that the bubble size predicted by both the granular kinetic model and the particle-bed model is in good agreement with the Darton's equation.

scholarly journals Clinical significance of late diastolic tissue doppler parameters after onset of STEMI: from the view point of the timing of the echocardipography

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N Iwahashi ◽  
J Kirigaya ◽  
M Horii ◽  
T Abe ◽  
E Akiyama ◽  
...  
Keyword(s):  
Tissue Doppler ◽  
Atrial Function ◽  
Diastolic Velocity ◽  
Long Time ◽  
Group A ◽  
St Elevation ◽  
Group B ◽  
First Time

Abstract Background The early transmitral flow velocity (E) divided by the early diastolic velocity of the mitral valve annulus (e') is referred to as the “E/e' ratio,” is useful even for ST elevation acute myocardial infarction (STEMI). However, the role of late diastolic velocity (a') which reveals the atrial function for STEMI is still unclear. Objectives We evaluated the clinical usefulness of tissue Doppler including atrial function for a first-time STEMI by long time follow up. Furthermore, we evaluated the meaning of each parameters by performing immediately after PCI or 2 weeks later. Methods We treated consecutive 571 first-time STEMI patients by immediate PCI within 12 hours after onset, and we examined 270 patients at immediately after PCI (GroupA, 65 years, 250 male) and 301 patients at 2 weeks after onset (GroupB, 64 years, 243 male). We examined trans mitral flow and TDI, then defined E/e' as LV filling pressure and A/a' as left atrial function. We followed them for a long time (>5 years). The primary end point (PE) was cardiac death or re-admission for heart failure (HF). Results We followed the patients in Group A for 10 years, Group B for 5 years. PE occurred in 64 patients in GroupA during 10 years, and 45 patients in GroupB during 5 years. We analyzed the univariate and multivariate Cox hazard analyses and we compared e' and a', E/e' and A/a' (Table). In GroupA, a' and A/a' were the independent predictors, on the other hand neither a' nor A/a' were the predictors in GroupB. E/e' was an independent predictor both in GroupA and B. Conclusion TDI parameters have different meanings by the timing of echocardiography after onset of a first-time STEMI. These results demonstrated that atrial dysfunction immediately after onset of STEMI suggests the poor prognosis after STEMI. Cox Hazard Proportional Analysis Funding Acknowledgement Type of funding source: None

Effects of spaceflight on rat erythroid parameters

1996 ◽  
Vol 81 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Z. Allebban ◽  
L. A. Gibson ◽  
R. D. Lange ◽  
T. L. Jago ◽  
K. M. Strickland ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Life Sciences ◽  
Lower Number ◽  
Ground Control ◽  
Colony Forming Unit ◽  
Human Erythropoietin ◽  
Group A ◽  
Group B ◽  
First Time ◽  
Group D

Hematologic studies were performed on 21 ground control rats and 21 rats flown during the Spacelab Life Sciences-2 14-day mission. Group A (n = 5) was used to collect blood in flight and 9 days postflight, group B (n = 5) was injected with recombinant human erythropoietin (rhEpo), group C (n = 5) received saline as a control, and group D (n = 6) was killed in flight and tissues were collected. Results indicated no significant changes in peripheral blood erythroid elements between flight and ground control rats. The nonadherent bone marrow on flight day 13 showed a lower number of recombinant rat interleukin-3 (rrIL-3)-responsive and rrIL-3 + rhEpo-responsive blast-forming unit erythroid (BFU-e) colonies in flight rats compared with ground control rats. On landing day, a slight increase in the number of rhEpo + rrIL-3-responsive BFU-e colonies of flight animals compared with ground control rats was evident. Nine days postflight, bone marrow from flight rats stimulated with rhEpo alone or with rhEpo + rrIL-3 showed an increase in the number of colony-forming unit erythroid colonies and a decrease in BFU-e colonies compared with ground control rats. This is the first time that animals were injected with rhEpo and subsequently blood and tissues were collected during the spaceflight to study the regulation of erythropoiesis in microgravity.

scholarly journals Comparative Study of Alkaloid Pattern of Four Bulgarian Fumaria Species

2016 ◽  
Vol 11 (2) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Tsvetelina Doncheva ◽  
Gabriela Yordanova ◽  
Vassil Vutov ◽  
Nadezhda Kostova ◽  
Stefan Philipov
Keyword(s):  
Comparative Study ◽  
Isoquinoline Alkaloids ◽  
Alkaloid Composition ◽  
Phytochemical Investigation ◽  
Group A ◽  
Group B ◽  
First Time

The alkaloid pattern of four Fumaria species ( Fumaria kralikii, Fumaria rostellata, Fumaria schleicherii, Fumaria thuretii) growing in Bulgaria was investigated by GC-MS and twenty isoquinoline alkaloids were determined. Phytochemical investigation of the alkaloid composition on Fumaria thuretii Boiss was made for the first time. The alkaloid profile of the species was compared at two levels, between different species and within two species from different habitats. Two chemotypical groups, based on the types of isoquinoline alkaloids were suggested. To group A belong species F. kralikii, F. rostellata (F. r. 1) and F. thuretii containing more than 50% spirobenzylisoquinoline alkaloids of the crude alkaloid mixtures. To group B belong species F. rostellata (F. r. 2) and F. schleicherii containing more than 40% protopine alkaloids and relatively high percentage phthaldeisoquinoline alkaloids (11–19%). In group A phthaldeisoquinoline alkaloids were not detected.

scholarly journals Cisplatin combined with capecitabine-induced chemotherapy for local nasopharyngeal carcinoma can improve the quality of life and reduce toxic and side effects

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ying Gao ◽  
Zhe Liu ◽  
Yiting Liu
Keyword(s):  
Quality Of Life ◽  
Side Effects ◽  
Nasopharyngeal Carcinoma ◽  
Short Term ◽  
Intravenous Drip ◽  
Group A ◽  
Group B ◽  
First Time ◽  
Better Than

Abstract Background This study was designed to probe into the effect of cisplatin combined with capecitabine on nasopharyngeal carcinoma (NPC). Methods A total of 136 NPC patients treated for the first time in our hospital from January 2016 to March 2017 were collected and divided into two groups: A and B. Among them, 66 in group A were treated with cisplatin intravenous drip, while 70 in group B were treated with capecitabine on the basis of group A. The efficacy, toxic and side effects, and quality of life of the two groups were observed. Results The short-term efficacy of group B was better than that of group A (p<0.05). The toxic and side effects of group B were lower than that of group A (p<0.05). The quality of life in group B was higher than that in group A (p<0.05). Conclusions Cisplatin combined with capecitabine-induced chemotherapy for local NPC can improve the quality of life and reduce the toxic and side effects.

scholarly journals Fascitis plantar. Estudio comparativo entre tres esquemas terapéuticos. [Plantar fasciitis. Comparative study between 3 therapeutic schemes]

2019 ◽  
Vol 84 (4) ◽  
pp. 336-341
Author(s):  
Ignacio Arzac Ulla
Keyword(s):  
Plantar Fasciitis ◽  
Plantar Flexion ◽  
Plantar Fascia ◽  
Return Time ◽  
Current Treatment ◽  
Group A ◽  
Comparative Results ◽  
Group B ◽  
First Time

Introducción: La fascitis plantar, descrita, por primera vez, por Plettner, es la causa más común de dolor en el talón. Su etiología continúa en estudio, participan factores anatómicos, como el acortamiento de la flexión plantar, y relacionados con el aumento de peso. Si bien no se ha publicado cuál es el mejor tratamiento para este cuadro, se recomienda el tratamiento conservador temprano. El objetivo de este estudio fue comparar tres métodos de tratamiento de la fascitis plantar.Materiales y Métodos: Entre marzo de 2016 y marzo de 2017, se trató a 90 pacientes con fascitis plantar, quienes fueron divididos en tres grupos, según el tratamiento recibido: grupo A o de control, ejercicios de elongación de la fascia plantar; grupo B, infiltración corticoanestésica y ejercicios de elongación de la fascia plantar, y grupo C, infiltración con solución salina y ejercicios de elongación de la fascia plantar. Resultados: Se mencionan los resultados comparativos sobre la base de la edad, el lado afectado, las enfermedades previas, la forma del pie, las cirugías previas del pie, el dolor posinfiltración, la escala analógica visual: grupo A: 0,73; grupo B: 1,03, grupo C: 2,7 y el tiempo hasta el retorno a la actividad previa: grupo A: 19.1 días, grupo B: 12.63 días, grupo C: 15.12 días. Conclusiones: Nuestro estudio demuestra que los tres tratamientos para la fascitis plantar son eficaces. La recuperación fue más rápida en los pacientes tratados con infiltración corticoanestésica, con un bajo número de complicaciones, pero sin diferencias a largo plazo. AbstractIntroduction: Plantar fasciitis, described for the first time by Plettner, is the most common cause of heel pain. In the etiology of this pathology under study, involved anatomical factors such as shortening of plantar flexion and related to weight gain. Although the current treatment does not exist in the current literature, the early start of conservative treatment has been recommended. The objective of the present study is to compare 3 treatment methods of plantar fasciitis. Materials and Methods: Between March 2016 and March 2017, 90 patients with plantar fasciitis were treated. They were divided into 3 groups based on the treatment performed. Group A or control: plantar fascia elongation exercises, Group B: anesthetic cortical infiltration and elongation exercises of plantar fascia and Group C: infiltration with saline solution and elongation exercises of plantar fascia.Results: Comparative results are mentioned based on age, affected side, previous pathologies, foot shape, previous foot surgeries, post infiltration pain, analogous visual scale Group A: 0.73 Group B: 1.03 Group C: 2.7 and return time a previous activity Group A: 19.1 days Group B: 12.63 days Group C: 15.12 days.Conclusions: Our study shows that the three treatments for PF are effective, seeing a recovery in less time to patients treated with anesthetic cortical infiltration with a low number of complications but no long-term differences.

scholarly journals A randomized controlled study of anterior lumbar plexus combined with parasacral sciatic nerve block under the guidance of ultrasound and nerve stimulator in elderly patients undergoing hip arthroplasty

2021 ◽  
Author(s):  
Wei Wu ◽  
Wen-hao Bu ◽  
Hai-bin Huang ◽  
Ying Mao ◽  
Yong-xing Tan
Keyword(s):  
Sciatic Nerve ◽  
Elderly Patients ◽  
Nerve Block ◽  
Hip Arthroplasty ◽  
Skin Incision ◽  
Sciatic Nerve Block ◽  
Lumbar Plexus ◽  
Group A ◽  
Group B ◽  
First Time

Abstract Objectives: To explore the clinical application of anterior lumbar plexus combined with parasacral nerve block under the dual guidance of ultrasound and nerve stimulator in elderly hip arthroplasty.Methods: Forty elderly patients aged from 65 to 85 years old who underwent unilateral hip arthroplasty (Except for revision of hip joint) were randomly divided into two groups (n=20 in each group): ultrasound-guided anterior lumbar plexus combined with parasacral sciatic nerve block group (group A) and ultrasound-guided anterior lumbar plexus block group (group B). Both groups were assisted with sedation with different doses of dexmetopyrimidine and analgesia with different doses of sufentanil. Because the orthopaedic team of our hospital performed hip arthroplasty with mature technique and fixed operation time, the onset time of block in group An and B, heart rate and blood pressure at admission (T0), skin incision (T1), half hour after skin incision (T2) and skin suture(T3), intraoperative dosage ofdexmedetomidine and sufentanil, postoperative 1, 4, 8, 16, 24hVAS score and the first time of getting out of bed were recorded.Results: the heart rate and blood pressure at T1, T2 and T3 in group A were significantly lower than those in group B (P < 0.05). The amount of sufentanil used during operation in group), A was significantly lower than that in group B (P < 0.05). The postoperative scores of 1,4,8,16 and 24hVAS in group), A were significantly lower than those in group B (P < 0.05), and the time of getting out of bed for the first time after operation was shorter than that in group B (P < 0.05).Conclusion: compared with simple anterior lumbar plexus block, anterior lumbar plexus combined with parasacral sciatic nerve block in elderly patients with hip arthroplasty can make the intraoperative circulation more stable, the intraoperative dosage of opioids significantly reduced and the effect of early postoperative analgesia is better. it can also shorten the time for patients to get out of bed for the first time.

scholarly journals Comparative Study on Planned repeat Caesarean Section and Unplanned Repeat Caesarean Section

2016 ◽  
Vol 24 (1) ◽  
pp. 57-61
Author(s):  
Jinnatun Nur ◽  
Rashida Khanom ◽  
Sumaya Akter
Keyword(s):  
Caesarean Section ◽  
Subsequent Pregnancy ◽  
T Test ◽  
P Value ◽  
Retrospective Case ◽  
College Hospital ◽  
Medical College ◽  
Group A ◽  
Group B ◽  
First Time

Repeat Caesarean section always carries more risk than first time caesarian delivery. In our country, antenatal care is always neglected. When this negligence occurs during subsequent pregnancy who had already goes on Caesarean section for the first pregnancy. In our study, we try to compare between the planned and unplanned repeat Caesarean section. The study was carried out at Mymensingh Medical College Hospital, Mymensingh and Amina Nursing Home at Charpara Mymensingh. This was a retrospective case control study, There were 100 patients in Group: A, (Planned repeat Caesarean section), Group B was also consisted with 100 patients (Unplanned repeat Caesarean section). Odd ratio was measured. Odd ratio between group; A and Group: B was 2.8. The two groups were compared by their age and independent t test was carried out. Group: A. Mean ± SD 25.76 ± 4.461Group: B. Mean ± SD = 26.12 ± 5.513. By pair independent t test: P value: .076ns. So we can conclude that regular antenatal Check up is mandatory for those whose 1st delivery was conducted by Caesarean section irrespective of age and economical status.J Dhaka Medical College, Vol. 24, No.1, April, 2015, Page 57-61

scholarly journals Application of 3-Dimensional Printing Guide Template and Pointed Lotus-Style Regulator in Percutaneous Pedicle Screw Fixation for Thoracolumbar Fractures

2021 ◽  
Author(s):  
Ming Zhang ◽  
Jiayi Li ◽  
Tao Fang ◽  
Jing Yan ◽  
Lungang Wu ◽  
...  
Keyword(s):  
3D Printing ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screw Fixation ◽  
3 Dimensional ◽  
Percutaneous Pedicle Screw ◽  
Group A ◽  
Group B ◽  
Percutaneous Pedicle Screw Fixation ◽  
First Time

Abstract This study aims to analysis the efficacy of the 3D printing percutaneous guide template in combination with the pointed lotus-style regulator in percutaneous pedicle screw fixation.60thoracolumbar fractures patients receiving percutaneous pedicle screw fixation (PPSF) were enrolled and randomly divided into 3 groups. Patients in Group A received traditional PPSF, while patients in Group B received PPSF with flat end lotus-style regulator and patients in Group C received PPSF with pointed lotus-style regulator. The experimental results showed that the highest number of pedicle screw successfully inserted by the first time was in group C, while lowest in group A (P<0.05). The total time of fluoroscopy and operation were lower in group C, and higher in group A (P<0.05). VAS and ODI scores were all lower after surgery than before surgery in 3groups. VAS and ODI scores were lower in group B and C, compared with group A at day 1 ,7 after surgery (P<0.05). KA decreased significantly in 3 groups after surgery and no difference in KA change between 3 groups (P>0.05). Taken together, Application of the 3D printing guide template in combination with pointed lotus-style regulator improved the accuracy of pedicle insertion.Trial registration: ClinicalTrials.gov Identifier: NCT04980131. Registered 18/07/2021.

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