scholarly journals Study on The Effect of Solid Properties on The Hydrodynamics in an Ebullated Bed Reactor

2021 ◽  
Vol 9 ◽  
Author(s):  
Luma H. Mahmod ◽  
◽  
Amer A. AbdulRahman ◽  
Mohammad F. Abid ◽  
◽  
...  
Keyword(s):  
Particle Size ◽  
Liquid Velocity ◽  
Negative Impact ◽  
Gas Holdup ◽  
Solid Loading ◽  
Multiphase System ◽  
Published Data ◽  
Cold Model ◽  
Hydrophobic Particles ◽  
Bubble Sizes

Published data on the hydrodynamics of ebullated- bed reactors (EBRs) used in the H-Oil process are scarce. In the present work, the effect of solid properties (e.g., particle size, and degree of hydrophobicity) on the hydrodynamics and foaminess in a lab-scale cold model of an (EBR) was investigated. 20wt. % MgSO4 solution was utilized as the liquid phase to imitate the hydrodynamic trends in the industrial-scale EBR of the hydro-conversion process. Experimental results depicted that the flow regime of the multiphase system can be readily evaluated by using the pressure drop technique. The turning from the bubbly to the turbulent system is enhanced with diminishing particle size, and decreasing particle hydrophobicity. Moreover, the degree of particle hydrophobicity was inversely proportional to the average gas holdup in the EBR. The reduction in average gas holdup was 7.9 % using hydrophobic particles more than that of the hydrophilic one. In the EBR, it was found that bubble sizes were increased with both gas velocity and the axial location far from the gas distributor while liquid velocity has negative impact on bubble size. The experimental work revealed that hydrophobic particles of smaller size (250 μrm) reduced foaming by 70% using 20 vol. % of solid loading and gas and liquid velocities of 10 and 0.15 cm s-1 respectively. This outcome revealed that the surface of catalyst particles used can be modified to act as foaminess- reducer in fluidized bed hydro conversion reactors.

Dip Coating From Density Mismatching Mixture

2021 ◽  
Author(s):  
Bashir Khoda ◽  
AMM Nazmul Ahsan ◽  
SM Abu Shovon
Keyword(s):  
Thin Film ◽  
Particle Size ◽  
Volume Fraction ◽  
Steel Wire ◽  
Cost Effective ◽  
Dip Coating ◽  
Solid Loading ◽  
Heterogeneous Mixture ◽  
Inorganic Particles ◽  
Inorganic Particle

Abstract Solid transfer technology from mixtures is gaining ever-increasing attention from materials scientists and production engineers due to their high potential in near net-shaped production of cost-effective engineering components. Dip coating, a wet deposition method, is an effective and straightforward way of thin-film/layers formation. The dipping mixtures are often embedded with inorganic fillers, nanoparticles, or clusters (d<30 nm) that produce a thin film ranging from nm to couple microns. An increase in the volume of solid transfer by the dipping process can open-up a novel 3D near-net-shape production. However, adding larger inorganic particle size (>1µm) or adding a higher solid fraction will increase the solid transfer but may result in a multi-phase heterogeneous mixture. In this work, the physical mechanism of an increased volume of solid transfer with a larger spherical particle size (>5 µm) is investigated. Polymer-based glue and evaporating solvent are mixed to construct the liquid carrier system (LCS). Moderate volume fraction of inorganic particles (20% < ?p < 50%) are added into the LCS solution as solid loading. Three levels of binder volume fraction are considered to investigate the effect of the solid transfer. Cylindrical AISI 304 steel wire with dia 0.81 mm is dipped and the coating thickness, weight, and the surface packing coverage by the particles are measured in our lab. The results presented the influence of volume fraction of inorganic particle and glue composition on the solid transfer from the heterogeneous mixture.

scholarly journals Dynamics of Bubbles Rising in Finite and Infinite Media

2003 ◽  
Author(s):  
Charles C. Maneri ◽  
Peter F. Vassallo
Keyword(s):  
High Speed ◽  
Velocity Model ◽  
System Size ◽  
Published Data ◽  
Rise Velocity ◽  
Velocity Measurements ◽  
Video System ◽  
Bubble Sizes ◽  
Quiescent Liquid ◽  
Infinite Media

The dynamic behavior of single bubbles rising in quiescent liquid Suva (R134a) in a duct has been examined through the use of a high speed video system. Size, shape and velocity measurements obtained with the video system reveal a wide variety of characteristics for the bubbles as they rise in both finite and infinite media. This data, coupled with previously published data for other working fluids, has been used to assess and extend a rise velocity model given by Fan and Tsuchiya. As a result of this assessment, a new rise velocity model has been developed which maintains the physically consistent characteristics of the surface tension in the distorted bubbly regime. In addition, the model is unique in that it covers the entire range of bubble sizes contained in the spherical, distorted and planar slug regimes.

Simulation of countercurrent gas–solid heat exchanger: Effect of solid loading ratio and particle size

2007 ◽  
Vol 27 (8-9) ◽  
pp. 1345-1351 ◽  
Author(s):  
K.S. Rajan ◽  
S.N. Srivastava ◽  
B. Pitchumani ◽  
B. Mohanty
Keyword(s):  
Particle Size ◽  
Heat Exchanger ◽  
Solid Loading ◽  
Loading Ratio

The impact of corona crisis on the economies of major metropolitan areas

2021 ◽  
pp. 145-159
Author(s):  
Т. Д. Polidi ◽  
A. Y. Gershovich
Keyword(s):  
Metropolitan Areas ◽  
Negative Impact ◽  
The United States ◽  
Economic Losses ◽  
Published Data ◽  
Russian Economy ◽  
Real Gdp ◽  
Regional Product ◽  
The Impact ◽  
Operational Assessment

The article presents the results of an operational assessment of the impact of the COVID-19 crisis on the change in the gross urban product (GUP) in 17 metropolitan areas of Russia with a population of more than 1 million people in 2020. The goal of the authors was to try to answer the most actual questions nowadays (early 2021): how deep was the fall of the largest agglomerations economies in Russia and abroad; did the corona crisis have a more negative impact on the largest metropolitan areas then on the rest of the economy? In order to answer these questions, two main tasks were: 1) to assess GUP in 17 largest metropolitan areas of Russia; 2) to consider foreign estimates of the GUP in 2020. For foreign comparisons, the authors use the first published data on changes in GDP and gross urban/regional product in the United States, Canada and Australia. The assessment of GUP in this work is carried out through the assessment of the component of employee compensation and then the transition to the GUP indicator on the assumption that such a ratio of compensation of employees to GDP in a city equals the average of the said ratios for the 17 metropolitan areas. The assessment showed that the real GDP growth rates in 2020 were negative not in all metropolitan areas, and in most of them economic losses turned out to be less than those of the Russian economy as a whole.

Stormwater runoff treatment filtration system and backwashing system

2019 ◽  
Vol 79 (4) ◽  
pp. 771-778 ◽  
Author(s):  
Junho Lee ◽  
Myungjin Lee
Keyword(s):  
Particle Size ◽  
Removal Efficiency ◽  
Recovery Rate ◽  
Stormwater Runoff ◽  
Pilot Scale ◽  
Solid Loading ◽  
Filter Media ◽  
Turbidity Removal ◽  
Filtration System ◽  
Combined Sewer

Abstract This study has been carried out to evaluate the applicability of the pilot scale hybrid type of stormwater runoff treatment system for treatment of combined sewer overflow. Also, to determine the optimum operation parameter such as coagulation dosage concentration, effectiveness of coagulant usage, surface loading rate and backwashing conditions. The pilot scale stormwater filtration system (SFS) was installed at the municipal wastewater plant serving the city of Cheongju (CWTP), Korea. CWTP has a capacity of 280,000 m3/day. The SFS consists of a hydrocyclone coagulation/flocculation with polyaluminium chloride silicate (PACS) and an upflow filter to treat combined sewer overflows. There are two modes (without PACS use and with PACS use) of operation for the SFS. In case of no coagulant use, the range of suspended solids (SS) and turbidity removal efficiency were 72.0–86.6% (mean 80.0%) and 30.9–71.1% (mean 49.3%), respectively. And, the recovery rate of filter was 79.2–83.6% (mean 81.2%); the rate of remaining solid loading in filter media was 16.4–20.8% (mean 18.8%) after backwashing. The influent turbidity, SS concentrations were 59.0–90.7 NTU (mean 72.0 NTU), 194.0–320.0mg/L (mean 246.7mg/L), respectively. The range of PACS dosage concentration was 6.0–7.1mg/L (mean 6.7mg/L). The range of SS and turbidity removal efficiency was 84.9–98.2 (mean 91.4%) and 70.7–96.3 (mean 84.0%), respectively. It was found that removal efficiency was enhanced with PACS dosage. The recovery rate of filter was 92.0–92.5% (mean 92.3%) the rate of remaining solid loading in filter media was 6.1–8.2% (mean 7.2%) after backwashing. In the case of coagulant use, the particle size of the effluent is bigger than influent particle size. The results showed that SFS with PACS use more effective than without PACS use in SS and turbidity removal efficiency and recovery rate of filter.

Biological attributes of Salibro™, a novel sulfonamide nematicide. Part 2: Impact on the fitness of various non-target nematodes

Nematology ◽  
2020 ◽  
pp. 1-17 ◽  
Author(s):  
Tim C. Thoden ◽  
Mariam A. Alkader ◽  
John A. Wiles
Keyword(s):  
Negative Impact ◽  
Soil Health ◽  
Agar Plate ◽  
Parasitic Nematodes ◽  
Published Data ◽  
Plant Parasitic Nematodes ◽  
Free Living ◽  
Plant Parasitic ◽  
Novel Products

Summary Currently a renaissance in chemical nematicides is taking place with novel products like Nimitz® (a.s. fluensulfone), Velum Prime® (a.s. fluopyram) and Salibro™ (a.s. fluazaindolizine – Reklemel™ active) entering the marketplace. Although a considerable amount of published data is already available on their laboratory and field impact on plant-parasitic nematodes, little is understood of their compatibility with the beneficial or free-living nematodes that are part of the soil health network. In a range of laboratory studies, the effects of these nematicides on the vitality and reproduction of several species was tested, including both cosmopolitan free-living nematodes (Acrobeloides, Cruznema, Panagrobelus) as well as commercially applied entomopathogenic nematodes (Steinernema, Heterorhabditis). Within aqueous exposure and agar plate in vitro assays, species sensitivity to those nematicides differed significantly but their fitness (vitality and reproduction; infectivity to insect hosts) was generally not adversely impacted by concentrations of 5-50 ppm (a.s.) of Salibro. Even at 250 ppm (a.s.) of Salibro only some species of the bacterial-feeding species showed some negative impact. By contrast, both Nimitz at 50 ppm (a.s.) and Velum at 5 ppm (a.s.) consistently demonstrated stronger adverse impacts. In second level soil drenching assays, either no, or occasionally slight, adverse effects on the natural community of free-living nematodes were observed if soils were drenched with different volumes of Salibro at 5-50 ppm (a.s.), while relatively stronger reductions were measured within the plant-parasitic species (especially root-knot nematodes). Both Nimitz and Vydate (a.s. oxamyl) showed some degree of compatibility at 5 and 25 ppm (a.s.), respectively, which was generally higher than for Velum Prime at 5 ppm (a.s.). Overall, these data indicate that, when used at common field rates, Salibro will be one of the best options as part of integrated nematode management programmes where the use of chemical nematicides is required.

PP116 Health Utilities And Neglected Conditions: A Chagas Disease Study

2018 ◽  
Vol 34 (S1) ◽  
pp. 110-111
Author(s):  
Sandro Miguel ◽  
Ângela Bagattini ◽  
Luciane Cruz ◽  
Eros de Almeida
Keyword(s):  
Quality Of Life ◽  
Chagas Disease ◽  
Negative Impact ◽  
Clinical Status ◽  
Cardiac Patients ◽  
Categorical Variables ◽  
Normative Values ◽  
Published Data ◽  
Utility Scores

Introduction:Chagas disease (ChD), also known as American trypanosomiasis, is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. About 6 to 7 million people worldwide are estimated to be infected, most in Latin America. Health-related quality of life (HRQoL) and utility measures are still poorly employed for assessment of ChD lifetime impairments. Brazilian HRQoL published data showed that the cardiac subgroup of patients have worse scores than other ChD chronic groups. For the time being, utility scores are not available yet for the ChD population. The present study aims to assess quality of life (QoL), as utility scores, of patients with chronic Chagas Disease.Methods:This is a cross-sectional study. Data were collected from 183 outpatients with chronic ChD in a reference center in Brazil. Information pertaining to sociodemographics, clinical status, and quality of life were collected using self-administered questionnaires. Utilities were obtained by the European Quality of Life – 5 Dimensions (EQ-5D) questionnaire. Comparisons were made between clinical subtypes and population normative values. Continuous variables were compared using t-test or ANOVA, and categorical variables were compared using Chi-square test. Associations between QoL and patient characteristics stratified by demographics, clinical status were identified by linear regression models.Results:Most subjects were female (61 percent). The average age of men was 53.3 years and women 56.6. When analyzing the EQ-5D utility scores, it was observed that the results were lower for cardiac patients (0.610–95% CI 0.582–0.638) in comparison to indeterminate form patients (0.659–0.632–0.687). When comparing patients with the general population of the same age and sex, patients with ChD showed lower utility scores than normative values (0.624–95% CI 0.596–0.652).Conclusions:Chronic ChD causes a negative impact on quality of life, physical functioning, as well as psychosocial function, with the impairment becoming worse in cardiac patients.

Changes in Particle Size and Crystallinity in Ground Nickel Powder

2008 ◽  
Vol 587-588 ◽  
pp. 468-472
Author(s):  
J.M. González ◽  
José A. Rodríguez ◽  
Enrique J. Herrera
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Crystallite Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Nickel Powder ◽  
Milling Time ◽  
High Energy ◽  
Published Data ◽  
Average Particle

Nickel powder was dry-milled using a high-energy disc-oscillating mill. The average particle size increases and the specific surface area diminishes with milling time. Crystallite size decreases and microstrains increase, under the same conditions, as shown by X-ray analysis. At 120 min milling time, the crystallite size has a value of 17 nm, i.e., a nanostructured powder, with a perturbed lattice, is obtained. The above results have been compared with published data about the effects of milling on a ceramic powder. There is, in both cases, a general agreement concerning the changes produced in crystallite size. Nevertheless, opposite results are reached regarding particle size and specific surface area.

Impact of 1p Deletions in Myelodysplastic Syndromes and Secondary AML Arising from Myelodysplastic Syndromes

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2006-2006
Author(s):  
Claudia Haferlach ◽  
Anna Stengel ◽  
Manja Meggendorfer ◽  
Wolfgang Kern ◽  
Torsten Haferlach
Keyword(s):  
Myelodysplastic Syndromes ◽  
Negative Impact ◽  
Chromosome 1 ◽  
Published Data ◽  
Employment Equity ◽  
Secondary Aml ◽  
Micro Rnas ◽  
Genomic Array ◽  
1P Deletion ◽  
Equity Ownership

Background: Deletions in the short arm of chromosome 1 are rare, recurrent abnormalities in Myelodysplastic syndromes (MDS) and are observed as the sole abnormality in 0.2% (Schanz et al. JCO 2012). So far no comprehensive characterization of this subset has been performed. Aim: The aim of this study was to characterize MDS and secondary AML evolving from MDS harboring a 1p deletion with respect to 1) accompanying cytogenetic and molecular genetic abnormalities, 2) the size of the 1p deletion and the minimal deleted region. Patients and Methods: 50 cases with MDS (de novo MDS: n=38, t-MDS: n=8) and secondary AML evolving from MDS (n=4) harboring a 1p deletion were selected for analysis. All cases were evaluated by chromosome banding analysis. From 30 cases sufficient material was available to perform genomic array analysis (SurePrint G3 ISCA CGH+SNP Microarray, Agilent, Waldbronn, Germany) and amplicon sequencing to detect mutations in ASXL1, CBL, CSF3R, CSNK1A1, DNMT3A, ETNK1, ETV6, EZH2, GATA1, IDH1, IDH2, JAK, KIT, KRAS, MPL, NPM1, NRAS, RUNX1, SETBP1, SF3B1, SRSF2, TET2, TP53, and U2AF1. Variants of unknown significance were excluded from statistical analysis. Results: 62% were male and median age was 75 years (range: 35 - 91). The 1p deletion was the sole chromosomal abnormality in 5/50 cases (10%) and was accompanied by one, two and more than two additional aberrations in 12 (24%), 15 (30%), and 18 (36%) cases, respectively. In total 129 chromosome abnormalities were observed in addition to the 1p deletion (median per patient: 2, range: 0-9). Of these only 10 were balanced, while 119 were unbalanced abnormalities leading to gain or loss of chromosomal material. Loss of 1p was most frequently accompanied by del(5q) (n=24; 48%), +8 (n=20; 39%), 7q-/-7 (n=11; 22%), del(17p) (n=5; 10%), and -Y (n=3; 6%). In 15 cases (29%) a duplication of the short arm of chromosome 1 harboring the 1p deletion was observed. Genomic array analyses revealed a median size of the 1p deletion of 25 MB (range: 13-34 MB). A minimal deleted region encountered in all 30 evaluable patients ranged from genomic position 17,872,935 to 24,285,861 encompassing 72 genes (e.g. E2F2, ID3, PAX7, UBR4, ZBTB40) and 10 micro RNAs. One, 2, 3, and 4 mutations were present in 10 (33%), 8 (26%), 5 (17%) and 2 (7%) cases, respectively. No mutations in any of the analyzed genes were observed in 5 cases (17%). Mutations were detected in SF3B1 (16%), TET2 (16%), ASXL1 (13%), DNMT3A (13%), EZH2 (13%), NRAS (13%), SRSF2 (13%), TP53 (13%), JAK2 (10%), KRAS (7%), U2AF1 (7%), CALR (3%), IDH2 (3%), MPL (3%), RUNX1 (3%), and SETBP1 (3%). No mutations were detected in CBL, CSF3R, CSNK1A1, ETNK1, ETV6, GATA1, IDH1, KIT, and NPM1. Compared to published data (Bejar et al. NEJM 2012, Papaemmanuil et al. Blood 2013, Haferlach et al. Leukemia 2014) SF3B1 (20-30%) and TET2 (20-30%) mutations seem to be less frequent and mutations in TP53 (6-8%), EZH2 (5-7%), NRAS (4-5%) and KRAS (1-3%) more frequent in MDS with 1p deletion compared to an unselected MDS cohort. Patients harboring either a 1p deletion as the sole abnormality or a duplication of the deleted chromosome 1 (n=20) had an excellent prognosis (3 year overall survival (OS): 100%), while patients with a 1p deletion accompanied by -7/7q- (n=11) had a very poor outcome (3 year OS: 0%; p<0.001). Patients with 1p deletion and other accompanying cytogenetic abnormalities (n=19) had an intermediate outcome (3 year OS: 34%, p=0.03, p=0.003). Conclusions: 1) Interstitial deletions in the short arm of chromosome 1 are rare recurrent abnormalities in MDS. 2) 5q deletion, +8, -7/7q- are frequently observed in addition to 1p deletion. 3) Both MDS with a 1p deletion as the sole abnormality and MDS with a duplication of deleted chromosome 1 are associated with very favorable outcome. 4) Accompanying abnormalities, especially -7/7q- have a negative impact on outcome. Disclosures Haferlach: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Stengel:MLL Munich Leukemia Laboratory: Employment. Meggendorfer:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

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