scholarly journals Effect of Calcium Treatment on Inclusions in H08A Welding Rod Steel

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1227
Author(s):  
Fangjie Lan ◽  
Changling Zhuang ◽  
Changrong Li ◽  
Guangkai Yang ◽  
Hanjie Yao
Keyword(s):  
Melting Point ◽  
Molten Steel ◽  
Calcium Aluminate ◽  
Large Scale ◽  
Energy Dispersive Spectrometer ◽  
Calcium Content ◽  
Calcium Treatment ◽  
Inclusion Composition ◽  
Metallic Inclusions ◽  
Before And After

The effect of calcium treatment on inclusions in H08A welding rod steel was studied by industrial experiment and using thermodynamics theory. The effects of inclusion composition, morphology, quantity, and size in H08A welding rod steel before and after calcium treatment were studied by metallographic microscope, scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). Thermodynamic studies show that the addition of calcium can form various forms of xCaO·yAl2O3, under the condition that the composition of molten steel remains unchanged, the control of calcium content is the key to generate low melting point calcium-aluminate complex non-metallic inclusions and improve the quality of molten steel. The production practice in steel plant shows that for welding rod steels, the calcium content in a suitable range can meet the requirements of calcium treatment. Effective calcium treatment can not only transform the high melting point Al2O3 inclusions into the low melting point complex non-metallic inclusions between 3CaO·Al2O3 and 12CaO·7Al2O3, but also make the original shape-diversified inclusions into the spherical calcium-aluminate complex non-metallic inclusions. Meanwhile, the total number of inclusions and large-scale inclusions in welding rod steel are reduced, and the inclusions tend to disperse in the steel, which is very conducive to the improvement of steel quality. The results show that the modification path of magnesium aluminate spinel in steel is as follows: Al2O3 → MgO-Al2O3 → MgO-CaO-Al2O3. In addition, calcium treatment can modify MgO-Al2O3 spinel in steel into liquid MgO-CaO-Al2O3 complex non-metallic inclusions with low melting point.

Effect of reoxidation on inclusions in steel during calcium treatment

2019 ◽  
Vol 116 (2) ◽  
pp. 206 ◽  
Author(s):  
Ming Li ◽  
Yang Liu ◽  
Lifeng Zhang
Keyword(s):  
Contact Angle ◽  
Sulfur Content ◽  
Molten Steel ◽  
Driving Force ◽  
Calcium Content ◽  
Slag Layer ◽  
Calcium Treatment ◽  
Total Oxygen ◽  
Limited Degree ◽  
Inclusions In Steel

In the current study, the effect of reoxidation on inclusions during calcium treatment was studied via adding Fe2O3 into a Al-killed molten steel at 1 min after the addition of calcium. The total oxygen (T.O.) content increased from 10 to 24 ppm just after the reoxidation occurred, while it finally decreased to 14 ppm since inclusions were floated to the top of the steel and absorbed by the formed slag layer. The increased T.O. favored the decomposition of CaS, especially for the heat with high sulfur contents. The vaporization of calcium, which leads to the decrease of calcium content, is the driving force for the evolution of inclusions from CaO-CaS-(Al2O3) to CaO-Al2O3-(CaS) due to the limited degree of reoxidation. The contact angle between inclusions and the molten steel increased with the increase of Al2O3 in calcium alumina, which favored the removal of inclusions. Increased sulfur content decreased the surface tension of molten steel, which led to remove less inclusions since the contact angle between inclusions and the molten steel was decreased. Thus, more inclusions were measured in heats with higher sulfur content.

scholarly journals Evolution of oxide and nitride inclusions during processing of stainless steel

2021 ◽  
Vol 121 (8) ◽  
pp. 1-6
Author(s):  
Y. Kacar ◽  
D. Kruger ◽  
P.C Pistorius
Keyword(s):  
Stainless Steel ◽  
Titanium Nitride ◽  
Calcium Aluminate ◽  
Nonmetallic Inclusions ◽  
Chromium Steel ◽  
Calcium Treatment ◽  
Inclusion Composition ◽  
Calcium Aluminates ◽  
Liquid Calcium

Because of its superior properties, stainless steel has been widely used for many applications. Nonmetallic inclusions can influence the quality of stainless steel products. A set of samples was used to track the response of inclusion composition during processing of a heat of titanium-bearing 18% chromium steel, from deoxidation after decarburization, to the solidified slab. The oxide inclusions responded as expected to additions of deoxidizers and calcium treatment, changing from silica to alumina and spinels, and then to calcium aluminates. The samples confirmed that titanium nitride can nucleate on liquid calcium aluminate during steel solidification.

The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Active Site ◽  
Large Scale ◽  
Thrombin Generation ◽  
Factor Viia ◽  
Dependent Manner ◽  
Antithrombotic Agent ◽  
Before And After ◽  
Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

scholarly journals THU0642-HPR EVOLUTION OF THE PERCEPTIONS OF RA PATIENTS AFTER EDUCATION PATIENT SESSION TEACHING METHOTREXATE SELF-INJECTION A PROSPECTIVE PILOT STUDY

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 566.1-566
Author(s):  
S. Afilal ◽  
H. Rkain ◽  
B. Berchane ◽  
J. Moulay Berkchi ◽  
S. Fellous ◽  
...  
Keyword(s):  
Pilot Study ◽  
Patient Education ◽  
Median Duration ◽  
Large Scale ◽  
Education Session ◽  
Prospective Pilot Study ◽  
Mean Delay ◽  
Lack Of Information ◽  
Level Of Satisfaction ◽  
Before And After

Background:Methotrexate is a gold standard for treatment of RA. In our context, RA patients prefer to be injected by paramedics rather than self-injecting. This can be explained by patients’ bad perceptions of self-injection or lack of information. Appropriate self-injection education can therefore be an important element in overcoming these obstacles and improving disease self-management.Objectives:Compare the RA patients’ perceptions on methotrexate self-injection before and after a patient education session.Methods:Prospective pilot study that included 27 consecutive patients (81.5% female, mean age 44.4 years, illiteracy rate 40.7%) with RA (median duration of progression of 4 years, mean delay in referral for specialist of 6 months, median duration of methotrexate use of 1 year). The patients benefited from an individual patient education session to learn how to self-inject with methotrexate subcutaneously. The patient education session was supervised by a nurse and a rheumatologist with a control a week later. Perceptions of the reluctance to self-inject and the difficulties encountered by patients were assessed before the patient education session, after the 1st and 2nd self-injection of methotrexate using a 10 mm visual analog scale. Patients also reported their level of satisfaction (10 mm VAS) after the 1st and 2nd self-injection.Results:The mean duration of patient education session is 13 min.Table I compares the evolution of the degrees of reluctance to self-injection, the difficulties encountered, and the satisfaction experienced by the patients.Table 1.Evolution of RA patients’ perceptions on the methotrexate self-injection. (N = 27)BeforeAfter the 1stself-injectionAfter the 2end self-injectionpVAS reluctance (0-10mm)6,5 ± 3,62,2 ± 2,91,0 ± 2,3<0,0001VAS difficulty (0-10mm)7,5 ± 2,62,5 ± 2,71,0 ± 1,9<0,0001VAS satisfaction (0-10mm)-8,9 ± 1,89,5 ± 1,50,002Conclusion:This study suggests the effectiveness of a methotrexate self-injection patient education session in RA patients. It also highlights the value of patient education in rheumatologic care. A large-scale study is necessary to better interpret and complete these preliminary results from this pilot study.Disclosure of Interests:None declared

scholarly journals Dynamic variations in salinity and potassium grade of a potassium-rich brine deposit in Lop Nor basin, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lichun Ma ◽  
Kai Wang ◽  
Yu Zhang ◽  
Qingfeng Tang ◽  
Hui Yan
Keyword(s):  
Large Scale ◽  
Sustainable Use ◽  
Potassium Sulfate ◽  
Middle Pleistocene ◽  
Underground Brine ◽  
Average Decrease ◽  
Rational Development ◽  
Mining History ◽  
Before And After ◽  
Lop Nor

AbstractThe Quaternary Lop Nor playa is the largest production base of potassium sulfate in the world. It has a mining history of more than 10 years, and its share in the Chinese potassium sulfate market is about 50% to-date. In this basin, the high-salinity potassium-rich brines are mainly contained in Middle Pleistocene–Holocene glauberite strata. Based on the monitoring of the underground brine table and geochemical analysis, this study reveals variations in the underground brine table and potassium-bearing grade before and after large-scale mining in the Lop Nor potash deposit. The results showed that the underground brine table and potassium sulfate grade decreased by varying degrees over sub-mineral areas after large-scale mining. The underground brine table declined by 8.5 m, on average, in the Luobei depression, by 6.4 m in the Tenglong platform and by 1.9 m in the Xinqing platform. However, the potassium-bearing grade showed the different trend. The Tenglong platform had the largest decline with average decreases in layers W1, W2 and W3 of 18.2%, 13.0% and 24.8%, respectively. In the Xinqing platform, the average decrease in layersW2 and W3 were 17.4% and 16.0% respectively. The Luobei depression decreases were relatively small (W1, W2 and W3 decreased 4.3%, 4.2% and 3.1%, respectively). This research provides a theoretical basis for the rational development and sustainable use of the potassium-rich brines in the Lop Nor basin.

scholarly journals Species and characteristics of volatile organic compounds emitted from an auto-repair painting workshop

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Y. Song ◽  
H. Chun
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Large Scale ◽  
Butyl Acetate ◽  
Small Scale ◽  
Indoor Environments ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Before And After ◽  
Adsorption Systems

AbstractVolatile organic compounds (VOCs) are secondary pollutant precursors having adverse impacts on the environment and human health. Although VOC emissions, their sources, and impacts have been investigated, the focus has been on large-scale industrial sources or indoor environments; studies on relatively small-scale enterprises (e.g., auto-repair workshops) are lacking. Here, we performed field VOC measurements for an auto-repair painting facility in Korea and analyzed the characteristics of VOCs emitted from the main painting workshop (top coat). The total VOC concentration was 5069–8058 ppb, and 24–35 species were detected. The VOCs were mainly identified as butyl acetate, toluene, ethylbenzene, and xylene compounds. VOC characteristics differed depending on the paint type. Butyl acetate had the highest concentration in both water- and oil-based paints; however, its concentration and proportion were higher in the former (3256 ppb, 65.5%) than in the latter (2449 ppb, 31.1%). Comparing VOC concentration before and after passing through adsorption systems, concentrations of most VOCs were lower at the outlets than the inlets of the adsorption systems, but were found to be high at the outlets in some workshops. These results provide a theoretical basis for developing effective VOC control systems and managing VOC emissions from auto-repair painting workshops.

scholarly journals Correcting for experiment-specific variability in expression compendia can remove underlying signals

GigaScience ◽  
2020 ◽  
Vol 9 (11) ◽  
Author(s):  
Alexandra J Lee ◽  
YoSon Park ◽  
Georgia Doing ◽  
Deborah A Hogan ◽  
Casey S Greene
Keyword(s):  
Gene Expression ◽  
Large Scale ◽  
Original Signal ◽  
Batch Effects ◽  
Technical Variability ◽  
The Past ◽  
Statistical Correction ◽  
Before And After ◽  
Data Collections ◽  
Biological Patterns

Abstract Motivation In the past two decades, scientists in different laboratories have assayed gene expression from millions of samples. These experiments can be combined into compendia and analyzed collectively to extract novel biological patterns. Technical variability, or "batch effects," may result from combining samples collected and processed at different times and in different settings. Such variability may distort our ability to extract true underlying biological patterns. As more integrative analysis methods arise and data collections get bigger, we must determine how technical variability affects our ability to detect desired patterns when many experiments are combined. Objective We sought to determine the extent to which an underlying signal was masked by technical variability by simulating compendia comprising data aggregated across multiple experiments. Method We developed a generative multi-layer neural network to simulate compendia of gene expression experiments from large-scale microbial and human datasets. We compared simulated compendia before and after introducing varying numbers of sources of undesired variability. Results The signal from a baseline compendium was obscured when the number of added sources of variability was small. Applying statistical correction methods rescued the underlying signal in these cases. However, as the number of sources of variability increased, it became easier to detect the original signal even without correction. In fact, statistical correction reduced our power to detect the underlying signal. Conclusion When combining a modest number of experiments, it is best to correct for experiment-specific noise. However, when many experiments are combined, statistical correction reduces our ability to extract underlying patterns.

Large-Scale Sport Events and Resident Well-Being: Examining PERMA and the Gold Coast 2018 Commonwealth Games

2021 ◽  
pp. 1-14
Author(s):  
Jason Doyle ◽  
Kevin Filo ◽  
Alana Thomson ◽  
Thilo Kunkel
Keyword(s):  
Large Scale ◽  
Positive Emotions ◽  
Well Being ◽  
Host Community ◽  
Social Psychological ◽  
Community Members ◽  
Community Based ◽  
Before And After ◽  
Sport Events ◽  
Commonwealth Games

Delivering community-based benefits is oftentimes cited to justify the high costs associated with hosting large-scale events. The current research is embedded in positive psychology to examine how an event impacts host community members’ PERMA domains, reflected through positive emotions, engagement, relationships, meaning, and accomplishment. Adopting a longitudinal approach, the authors interviewed 15 host community members before and after a large-scale sport event to determine if and how the event impacted their well-being. The findings uncovered evidence that the event activated positive emotions, relationships, and meaning across both phases, and evidence of accomplishment within the postevent phase. The findings contribute to the knowledge by examining the links between large-scale sport events and well-being throughout the event lifecycle. This research forwards implications for event bidding committees, event organizers, and host community officials to maximize community well-being through hosting large-scale events and to help justify associated expenses from a social–psychological perspective.

Pre- and Post-Tsunami Depth Changes of Submarine Topography for the Analysis of Submarine Landslide-Induced Tsunami: Proposal of Digitization Method and Application to the Case of the 1923 Great Kanto Earthquake Tsunamis

2021 ◽  
Author(s):  
Kazuki Murata ◽  
Shinji Sassa ◽  
Tomohiro Takagawa ◽  
Toshikazu Ebisuzaki ◽  
Shigenori Maruyama
Keyword(s):  
Large Scale ◽  
Interpolation Method ◽  
Weighted Average ◽  
Tokyo Bay ◽  
Submarine Landslides ◽  
Sagami Bay ◽  
Seabed Topography ◽  
Kanto Earthquake ◽  
Before And After ◽  
Tsunami Event

Abstract We first propose and examine a method for digitizing analog data of submarine topography by focusing on the seafloor survey records available in the literature to facilitate a detailed analysis of submarine landslides and landslide-induced tsunamis. Second, we apply this digitization method to the seafloor topographic changes recorded before and after the 1923 Great Kanto earthquake tsunami event and evaluate its effectiveness. Third, we discuss the coseismic large-scale seafloor deformation at the Sagami Bay and the mouth of the Tokyo Bay, Japan. The results confirmed that the latitude / longitude and water depth values recorded by the lead sounding measurement method can be approximately extracted from the sea depth coordinates by triangulation survey through the overlaying of the currently available GIS map data without geometric correction such as affine transformation. Further, this proposed method allows us to obtain mesh data of depth changes in the sea area by using the interpolation method based on the IDW (Inverse Distance Weighted) average method through its application to the case of the 1923 Great Kanto Earthquake. Finally, we analyzed and compared the submarine topography before and after the 1923 tsunami event and the current seabed topography. Consequently, we found that these large-scale depth changes correspond to the valley lines that flow down as the topography of the Sagami Bay and the Tokyo Bay mouth.

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