The Mixing Characteristics of Powder Injected through Top Lance in RH Degasser

2011 ◽  
Vol 396-398 ◽  
pp. 2098-2102 ◽  
Author(s):  
Cheng Wu Du ◽  
He Li Ma ◽  
Li Ying Li ◽  
Xue Liang Yin
Keyword(s):  
Similarity Theory ◽  
Mixing Time ◽  
Impurity Content ◽  
Water Model ◽  
Operating Parameters ◽  
High Quality ◽  
Quality Steel ◽  
The Past ◽  
Secondary Refining ◽  
Increasing Demand

With the increasing demand for high quality steel, various secondary refining techniques have been developed in the past decades. RH powder top blowing process (RH-PTB) is practiced in industry to decrease the impurity content of steel in a more economical way. In the present work, based on similarity theory, RH powder top blowing process was simulated by water model, and the effects of operating parameters on mixing time were investigated. The results show that the injected powder had a negligible effect on mixing time in RH-PTB, and the mixing time increases with top lance gas flowrate and decreases with lifting gas flowrate of up-leg. It was found that the mixing time was no longer decreasing as the lifting gas flowrate was over 15 L/min. Moreover, the height of top lance has some effect on mixing time in the reactor, and it should be adjusted to specific circumstances for purposes.

Effect of Melt Depth and Nozzle Type on the Mixing Behavior in Bottom-Blown Steelmaking Ladle – A Water Model Approach

2006 ◽  
Vol 510-511 ◽  
pp. 494-497 ◽  
Author(s):  
Sung-Ho Cho ◽  
Chang Won Kim ◽  
Jeong Whan Han ◽  
Byung Don You ◽  
Dong Sik Kim
Keyword(s):  
Gas Flow ◽  
Flow Behavior ◽  
Mixing Time ◽  
Porous Plug ◽  
Water Model ◽  
Operating Parameters ◽  
Chemical Compositions ◽  
Melt Temperature ◽  
Mixing Behavior ◽  
Nozzle Type

It is generally well known that a steelmaking ladle operation plays an important role in the production of clean steel. A turbulent mixing of melt with Ar gas bubbling from the ladle bottom can homogenize a melt temperature and can control precisely chemical compositions of steel. In order to figure out these phenomena, a quantitative analysis of fluid flow behavior of gas and melt during a ladle operation is required and special concerns should be focused on effects of operating parameters on the perfect mixing time of melt. In this study, as a basic approach, effects of operating parameters such as a melt depth (aspect ratio) and a nozzle type (one-hole or porous plug) on the mixing behavior in ladle operation are investigated. Water model experiments are carried out to simulate these melt behaviors in steelmaking ladle. As a result, it was found that there exist an optimized melt depth and a nozzle type at a given gas flow rate, which affect significantly on the mixing behavior of melt.

scholarly journals A Behaviour of Axially Loaded Steel Concrete Composite Long Columns with Basalt Fiber

2019 ◽  
Vol 8 (9S3) ◽  
pp. 1087-1090
Keyword(s):  
Mechanical Behavior ◽  
Compressive Strain ◽  
Basalt Fiber ◽  
Yield Strain ◽  
High Quality ◽  
Quality Steel ◽  
Test Execution ◽  
The Past ◽  
Axially Loaded ◽  
The Impact

Composite sections have numerous favorable circumstances over unadulterated steel and solid segments. From the past examinations, it has been demonstrated that the yield strain of the high-quality steel is more prominent than a definitive compressive strain of the solid when exposed to stacking. Consequently, this investigation is centered around the impact of early solid pounding on the conduct of the composite sections.In order to maximize the contribution of the concrete to prevent early crushing of the concrete, the concrete reinforced with basalt fiber was considered. In this project, there are twenty one column specimens were casted to study the mechanical behavior in detail. The impact of basalt fiber on the quality and disappointment conduct of composite sections were wanted to explore. For the structure of composite sections, the standard Eurocode-4 plan strategy has been pursued. To ponder the test execution of the proposed composite sections, the two closures with stuck help condition and hub stacking tests were considered

Mapping Power

2018 ◽  
Keyword(s):  
Political Economy ◽  
Comprehensive Analysis ◽  
Electricity Sector ◽  
Operational Performance ◽  
The Political ◽  
Government Reform ◽  
High Quality ◽  
The Past ◽  
Economic Forces ◽  
Political Economy Analysis

Electricity is critical to enabling India’s economic growth and providing a better future for its citizens. In spite of several decades of reform, the Indian electricity sector is unable to provide high-quality and affordable electricity for all, and grapples with the challenge of poor financial and operational performance. To understand why, Mapping Power provides the most comprehensive analysis of the political economy of electricity in India’s states. With chapters on fifteen states by scholars of state politics and electricity, this volume maps the political and economic forces that constrain and shape decisions in electricity distribute on. Contrary to conventional wisdom, it concludes that attempts to depoliticize the sector are misplaced and could worsen outcomes. Instead, it suggests that a historically grounded political economy analysis helps understand the past and devise reforms to simultaneously improve sectoral outcomes and generate political rewards. These arguments have implications for the challenges facing India’s electricity future, including providing electricity to all, implementing government reform schemes, and successfully managing the rise of renewable energy.

scholarly journals Levels of Evidence in Rhinology and Skull Base Surgery Research

2021 ◽  
pp. 019459982098713
Author(s):  
Jennifer A. Silver ◽  
Marco Mascarella ◽  
George Tali ◽  
Rickul Varshney ◽  
Marc A. Tewfik ◽  
...  
Keyword(s):  
Skull Base ◽  
Skull Base Surgery ◽  
Absolute Number ◽  
High Quality ◽  
Level Of Evidence ◽  
Levels Of Evidence ◽  
The Past ◽  
Significant Difference ◽  
Surgery Research ◽  
Based Medicine

Objective The purpose of this study was to evaluate the quality of evidence of rhinology and rhinologic skull base surgery (RSBS) research and its evolution over the past decade. Study Design Review article. Setting We reviewed articles from 2007 to 2019 in 4 leading peer-reviewed otolaryngology journals and 3 rhinology-specific journals. Methods The articles were reviewed and levels of evidence were assigned using the Oxford Centre for Evidence-Based Medicine 2011 guidelines. High quality was defined as level of evidence 1 or 2. Results In total, 1835 articles were reviewed in this study spanning a 13-year period. Overall, the absolute number of RSBS publications increased significantly 22.6% per year, from 108 articles in 2007 to 481 in 2019 ( P < .001; 95% CI, 7.9-37.2). In 2007, only 13 articles, or 15%, were high quality, and this grew to 146 articles, or 39%, in 2019. A 14.0% per year exponential increase in the number of high-quality publications was found to be statistically significant ( P < .001; 95% CI, 7.2, 20.7). Overall, high-quality publications represented just 25.8% of RSBS articles overall. There was no significant difference in quality between rhinology-specific journals and general otolaryngology journals (χ2 = 3.1, P = .077). Conclusion The number of overall publications and of high-quality RSBS publications has significantly increased over the past decade. However, the proportion of high-quality studies continues to represent a minority of total RSBS research.

scholarly journals The fossil record of whip spiders: the past of Amblypygi

PalZ ◽  
2021 ◽  
Author(s):  
Carolin Haug ◽  
Joachim T. Haug
Keyword(s):  
Fossil Record ◽  
3D Imaging ◽  
Three Dimensional ◽  
Dorsal Shield ◽  
Stereo Images ◽  
Geological Time ◽  
High Quality ◽  
The Past ◽  
Over Time

AbstractWhip spiders (Amblypygi), as their name suggests, resemble spiders (Araneae) in some aspects, but differ from them by their heart-shaped (prosomal) dorsal shield, their prominent grasping pedipalps, and their subsequent elongate pair of feeler appendages. The oldest possible occurrences of whip spiders, represented by cuticle fragments, date back to the Devonian (c. 385 mya), but (almost) complete fossils are known from the Carboniferous (c. 300 mya) onwards. The fossils include specimens preserved on slabs or in nodules (Carboniferous, Cretaceous) as well as specimens preserved in amber (Cretaceous, Eocene, Miocene). We review here all fossil whip spider specimens, figure most of them as interpretative drawings or with high-quality photographs including 3D imaging (stereo images) to make the three-dimensional relief of the specimens visible. Furthermore, we amend the list by two new specimens (resulting in 37 in total). The fossil specimens as well as modern whip spiders were measured to analyse possible changes in morphology over time. In general, the shield appears to have become relatively broader and the pedipalps and walking appendages have become more elongate over geological time. The morphological details are discussed in an evolutionary framework and in comparison with results from earlier studies.

Twisted oxide lateral homostructures with conjunction tunability

2021 ◽  
Author(s):  
Jan-Chi Yang ◽  
Ping-Chun Wu ◽  
Chia-Chun Wei ◽  
Qilan Zhong ◽  
Sheng-Zhu Ho ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Strain Engineering ◽  
Epitaxial Films ◽  
Modern Technology ◽  
Specific Substrate ◽  
Lattice Structures ◽  
High Quality ◽  
The Past ◽  
Sharp Interfaces ◽  
Selection Of

Abstract Epitaxial growth is of significant importance over the past decades, given it has been the key process of modern technology for delivering high-quality thin films. For conventional heteroepitaxy, the selection of proper single crystal substrates not only facilitates the integration of different materials but also fulfills interface and strain engineering upon a wide spectrum of functionalities. Nevertheless, the lattice structures, regularity and crystalline orientation are determined once a specific substrate is chosen. In this work, we reveal the growth of twisted oxide lateral homostructures with multiple conjunction degree of freedom. The twisted lateral homostructures with atomically sharp interfaces can be composed of epitaxial “blocks” with different crystalline orientations, ferroic orders and phases. We further demonstrate that this approach is universal for fabricating various complex systems. Our results establish an efficient pathway towards twisted lateral homostructures, allowing epitaxial films to be arbitrarily tailored at designated positions with unbounded in-plane conjunction tunability.

Deliberation, demobilization, and limited empowerment: a survey study on participatory pricing in China

2018 ◽  
Vol 19 (4) ◽  
pp. 694-708 ◽  
Author(s):  
Xuan Qin ◽  
Baogang He
Keyword(s):  
Negative Impact ◽  
Negative Relationship ◽  
Political Activism ◽  
Specific Form ◽  
Public Deliberation ◽  
Survey Study ◽  
High Quality ◽  
Low Level ◽  
The Past ◽  
Significant Negative Impact

AbstractAuthoritarian deliberation has been used widely to describe the specific form of deliberation developed in China. However, whether its practice will strengthen authoritarianism or lead to democratization remains unknown. In this study, we examine this question from the perspective of participants in public deliberation. Surveying the participants in participatory pricings held in Shanghai over the past 5 years, we find that participants’ perception of deliberative quality has a statistically significant negative impact on their level of political activism, while their level of empowerment has a moderating effect on this negative relationship. In this light, Chinese deliberative practices characterized by high-quality deliberation and low-level empowerment are likely to have a demobilization effect; thus, they reinforce the authoritarian rules.

scholarly journals Study of the Effect of a Plug with Torsion Channels on the Mixing Time in a Continuous Casting Ladle Water Model

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1942
Author(s):  
Gerardo Aguilar ◽  
Gildardo Solorio-Diaz ◽  
Alicia Aguilar-Corona ◽  
José Angel Ramos-Banderas ◽  
Constantin A. Hernández ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Mixing Time ◽  
Tangential Velocity ◽  
Water Model ◽  
Mixing Times ◽  
Low Velocity ◽  
Velocity Magnitude ◽  
Image Velocimetry ◽  
Casting Ladle ◽  
Upward Direction

The use of porous plugs in injecting gas through the bottom of a ladle forms vertical plumes in a very similar way to a truncated cone. The gas plume when exiting the plug has a smaller diameter compared to that formed in the upper zone of the ladle because inertial forces predominate over buoyancy forces in this zone. In addition, the magnitude of the plume velocity is concentrated in an upward direction, which increases the likelihood of low velocity zones forming near the bottom of the ladle, especially in lower corners. In this work, a plug with spiral-shaped channels with different torsion angles is proposed, with the objective that the gas, when passing through them, has a tangential velocity gain or that the velocity magnitude is distributed in the three axes and does not just focus on the upward direction, helping to decrease low velocity zones near the bottom of the ladle for better mixing times. For the experimentation, we worked in a continuous casting ladle water model with two configuration injections, which in previous works were reported as the most efficient in mixing the steel in this ladle. The results obtained using the PIV technique (particle image velocimetry) and conductimetry technique indicate that the plugs with the torsion channels at angles of 60° and 120° improve the mixing times for the two injection configurations.

scholarly journals Ventilation changes in the western North Pacific since the last glacial period

2011 ◽  
Vol 7 (4) ◽  
pp. 2719-2739 ◽  
Author(s):  
Y. Okazaki ◽  
T. Sagawa ◽  
H. Asahi ◽  
K. Horikawa ◽  
J. Onodera
Keyword(s):  
Sedimentation Rate ◽  
North Pacific ◽  
Western North Pacific ◽  
Glacial Period ◽  
High Quality ◽  
Last Glacial Period ◽  
The Past ◽  
High Sedimentation ◽  
The Last Glacial

Abstract. We reconstructed the ventilation record of deep water at 2100 m depth in the mid-latitude western North Pacific over the past 25 kyr from radiocarbon measurements of coexisting planktic and benthic foraminiferal shells in sediment with a high sedimentation rate. The 14C data on fragile and robust planktic foraminiferal shells were concordant with each other, ensuring high quality of the reconstructed ventilation record. The radiocarbon activity changes were consistent with the atmospheric record, suggesting that no massive mixing of old carbon from the abyssal reservoir occurred throughout the glacial to deglacial periods.

scholarly journals Citrus Pulp Recovery

1987 ◽  
Author(s):  
Teiko M. Johnson
Keyword(s):  
High Quality ◽  
The Past ◽  
Citrus Pulp ◽  
Citrus Juices ◽  
Juice Sacs ◽  
Sophisticated Technology

The growing interest in citrus pulp, or frozen, stabilized juice sacs, stems from the rapid influx of high quality citrus juices and juice added beverages into the market. Juice sacs have been recovered for many years and it has not been until the past few years that this practice evolved into a sophisticated technology. Paper published with permission.

Sign in / Sign up

Export Citation Format

Share Document