scholarly journals Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 619 ◽  
Author(s):  
Xiang Li ◽  
Xiao Long ◽  
Linzhu Wang ◽  
Shouhao Tong ◽  
Xiutao Wang ◽  
...  
Keyword(s):  
Outer Layer ◽  
Three Dimensional ◽  
Average Diameter ◽  
Inclusion Size ◽  
Number Density ◽  
Cooling Process ◽  
Oxide Inclusions ◽  
Industrial Experiments ◽  
Size Number

In order to study the effect of Ca and sulfur contents on the characteristics of inclusions, industrial experiments using 95CrMo steel were conducted. SEM-EDS detections and stereological analysis were used to probe the characteristics of inclusions, including their compositions, morphologies, size, number density, and distribution. The results indicate that there were mainly three types of inclusions in 95CrMo steel billets with 6–18 ppm Ca and 30–100 ppm S: inclusions with single-phased morphology mainly composed of oxides; isolated MnS/CaS-only inclusions; inclusions with multi-phased morphology. The three-dimensional inclusion size distribution suggests that there were more Type-1 inclusions with a small size in low S containing steels. The average diameter of all types of inclusions increased with increasing Ca or S content in 95CrMo steel, indicating that the formation of MnS and CaS coarsened their size. The density distribution of inclusions indicates that the more inclusions there are, the more easily they aggregate and collide. Moreover, it is presumably concluded that the formation of sulfide in the outer layer of oxide inclusions weaken the attraction between oxide inclusions. The equilibrated transformation and formation of inclusions during the cooling process of 95CrMo steel was discussed based on thermodynamic calculation. The equilibrated transformation trajectory of inclusions in 95CrMo steel during the cooling process was Ca2SiO4 + MgO → Ca3MgSi2O8 → Spinel + CaS, which was corresponding to the detected results. The precipitation regular of sulfide was obtained. The formation mechanism for three types of inclusions was discussed.

Industrial experiment study on inclusion evolution in 95CrMo Steel

2019 ◽  
Vol 116 (5) ◽  
pp. 518 ◽  
Author(s):  
Linzhu Wang ◽  
Junqi Li ◽  
Shufeng Yang ◽  
Chaoyi Chen ◽  
Huixin Jin ◽  
...  
Keyword(s):  
Molten Steel ◽  
Single Phase ◽  
Oxide Inclusion ◽  
Complex Oxides ◽  
Inclusion Size ◽  
Refining Process ◽  
Cooling Process ◽  
Sharp Angle ◽  
Industrial Experiment ◽  
Industrial Experiments

In order to clarify the evolution mechanism of inclusions in 95CrMo, the industrial experiments were conducted. The composition, morphology and size of inclusions during refining and solidifying processes were analyzed by SEM-EDS detection and thermodynamic calculations. The inclusion evolution during refining process in molten 95CrMo steel can be concluded as: Al2O3 → Al2O3-MgO-CaO/CaS → Al2O3-MgO-SiO2-CaO-CaS, which is affected by slag-metal reaction and corrosion of refractory. The change of inclusion size during refining was analyzed based on their collision and floatation behavior. The composition of inclusions in billets indicate that there were mainly five types of inclusions, including spinel with sharp angle, spherical oxide inclusion composed of Al2O3, MgO, SiO2 and CaO, oxide-sulfide inclusion with single phase, inclusion with duplex phase, and MnS inclusion. The type of inclusions affects their size. The thermodynamic results indicate that most complex oxides formed in molten steel and no spinel generated during cooling process. CaS formed in the molten steel after tundish metallurgy and there were still some CaS precipitated in solid steel. MnS precipitated after steel solidification. The calculated results based on FACTSAGE 7.1 are in agreement with experimental results on the whole.

Imaging of platinum-shadowed macromolecular complexes in dark field

1984 ◽  
Vol 42 ◽  
pp. 146-147
Author(s):  
D.W. Andrews ◽  
F.P. Ottensmeyer
Keyword(s):  
Thin Film ◽  
Three Dimensional ◽  
Average Diameter ◽  
Dark Field ◽  
Bright Field ◽  
Field Mode ◽  
Macromolecular Complexes ◽  
Average Mass ◽  
Topological Features ◽  
Projection Images

Shadowing with heavy metals has been used for many years to enhance the topological features of biological macromolecular complexes. The three dimensional features present in directionaly shadowed specimens often simplifies interpretation of projection images provided by other techniques. One difficulty with the method is the relatively large amount of metal used to achieve sufficient contrast in bright field images. Thick shadow films are undesirable because they decrease resolution due to an increased tendency for microcrystalline aggregates to form, because decoration artefacts become more severe and increased cap thickness makes estimation of dimensions more uncertain.The large increase in contrast provided by the dark field mode of imaging allows the use of shadow replicas with a much lower average mass thickness. To form the images in Fig. 1, latex spheres of 0.087 μ average diameter were unidirectionally shadowed with platinum carbon (Pt-C) and a thin film of carbon was indirectly evaporated on the specimen as a support.

scholarly journals A Microcomputed Tomographic Evaluation of Root Canal Morphology of Maxillary Second Premolars in a Pakistani Cohort

2021 ◽  
Vol 11 (11) ◽  
pp. 5086
Author(s):  
Mazen F. Alkahtany ◽  
Saqib Ali ◽  
Abdul Khabeer ◽  
Shafqat A. Shah ◽  
Khalid H. Almadi ◽  
...  
Keyword(s):  
Root Canal ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Micro Ct ◽  
Single Root ◽  
Root Canal Morphology ◽  
Spss Software ◽  
Variable Morphology ◽  
Canal Morphology

This study aimed to investigate variations in the root canal morphology of maxillary second premolar (MSP) teeth using microcomputed tomography (micro-CT). Sixty (N = 60) human extracted MSPs were collected and prepared for micro-CT scanning. The duration for scanning a single sample ranged between 30 and 40 min and a three-dimensional (3-D) image was obtained for all the MSPs. The images were evaluated by a single observer who recorded the canal morphology type, number of roots, canal orifices, apical foramina(s), apical delta(s), and accessory canals. The root canal configuration was categorized in agreement with Vertucci’s classification, and any configuration not in agreement with Vertucci’s classification was reported as an “additional canal configuration”. Descriptive statistics (such as mean percentages) were calculated using SPSS software. The most common types agreeing with Vertucci’s classification (in order of highest to lowest incidence) were types I, III, V, VII, II, and VI. The teeth also exhibited four additional configurations that were different from Vertucci’s classification: types 2-3, 1-2-3, 2-1-2-1, and 1-2-1-3. A single root was found in 96.7% and the majority of the samples demonstrated two canals (73.3%). Further, 80% of the teeth showed one canal orifice. The number of apical foramina’s in the teeth was variable, with 56.7% having solitary apical foramen. The accessory canal was found in 33.3%, and apical delta was found in only 20% of the samples. Variable morphology of the MSPs was detected in our study. The canal configuration most prevalent was type 1; however, the results also revealed some additional canal types.

scholarly journals Fabrication of Eutectic Ga-In Nanowire Arrays Based on Plateau–Rayleigh Instability

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4616
Author(s):  
Takashi Ikuno ◽  
Zen Somei
Keyword(s):  
Integrated Circuits ◽  
Substrate Surface ◽  
Three Dimensional ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Scanning Probe ◽  
Rayleigh Instability ◽  
Simple Method ◽  
Flat Substrate ◽  
Metal Nanowire

We have developed a simple method of fabricating liquid metal nanowire (NW) arrays of eutectic GaIn (EGaIn). When an EGaIn droplet anchored on a flat substrate is pulled perpendicular to the substrate surface at room temperature, an hourglass shaped EGaIn is formed. At the neck of the shape, based on the Plateau–Rayleigh instability, the EGaIn bridge with periodically varying thicknesses is formed. Finally, the bridge is broken down by additional pulling. Then, EGaIn NW is formed at the surface of the breakpoint. In addition, EGaIn NW arrays are found to be fabricated by pulling multiple EGaIn droplets on a substrate simultaneously. The average diameter of the obtained NW was approximately 0.6 μm and the length of the NW depended on the amount of droplet anchored on the substrate. The EGaIn NWs fabricated in this study may be used for three-dimensional wiring for integrated circuits, the tips of scanning probe microscopes, and field electron emission arrays.

Surface Modification of High Density Ceramic Powder for Increasing Suspension Capacity in Three-Dimensional Printing Application

2018 ◽  
Vol 936 ◽  
pp. 159-163 ◽  
Author(s):  
Huang Jan Hsu ◽  
Shyh Yuan Lee ◽  
Shinn Liang Chang ◽  
Cho Pei Jiang
Keyword(s):  
Surface Modification ◽  
Ball Milling ◽  
Ceramic Powder ◽  
Three Dimensional ◽  
Treatment Protocol ◽  
Weight Ratio ◽  
Average Diameter ◽  
Zirconia Powder ◽  
Three Dimensional Printing ◽  
Promising Tool

Three-dimensional slurry printing is a promising tool for making ceramic object but it limits in high dense ceramic powder because of poor suspension capacity. This study uses zirconia powder with an average diameter of 2 μm because its density is 5.67 g/cm3. A treatment protocol is proposed to improve the suspension capacity of zirconia powder including the ball milling, surface modification and resin blending. Experimental results show that adding 1% of isostearyl titanate, a coupling agent, for surface modification can enhance the lipophilicity of zirconia powder. Mixing surface modification powder in resin with a weight ratio of 7:3 and carrying on ball milling with 100 RPM for 6 hours can obtain the diameter of powder less than 400 nm. As a result, the zirconia slurry can obtain good suspension capacity which is over 48 hours.

scholarly journals Effect of Ti(C, N) Particle on the Impact Toughness of B-Microalloyed Steel

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 868 ◽  
Author(s):  
Yu Huang ◽  
Guo-Guang Cheng ◽  
Shi-Jian Li ◽  
Wei-Xing Dai ◽  
You Xie
Keyword(s):  
Impact Toughness ◽  
Microalloyed Steel ◽  
Fracture Initiation ◽  
Sem Analysis ◽  
Number Density ◽  
Size Number ◽  
Microalloying Elements ◽  
The Impact ◽  
Ti Content ◽  
Scanning Electron

Simultaneously improving the toughness and strength of B-microalloyed steel by adding microalloying elements (Nb, V, Ti) has been an extensively usedmethod for researchers. However, coarse Ti(C, N) particle will precipitate during solidification with inappropriate Ti content addition, resulting in poor impact toughness. The effect of the size, number density, and location of Ti(C, N) particle on the impact toughness of B-microalloyed steel with various Ti/N ratios was investigated. Coarse Ti(C, N) particles were investigated to act as the cleavage fracture initiation sites, by using scanning electron microscopy (SEM) analysis. When more coarse Ti(C, N) inclusions were located in ferrite instead of pearlite, the impact toughness of steel with ferrite–pearlite microstructure was lower. Meanwhile, when the size or the number density of Ti(C, N) inclusions was larger, the impact toughness was adversely affected. Normalizing treatment helps to improve the impact property of B-microalloyed steel, owing to the location of Ti(C, N) particles being partly changed from ferrite to pearlite. The formation mechanism of coarse Ti(C, N) particles was calculated by the thermodynamic software Factsage 7.1 and Thermo-Calc. The Ti(C, N) particles formed during the solidification of molten steel, and the N-rich Ti(C, N) phase precipitated first and, then, followed by the C-rich Ti(C, N) phase. Decreasing the Ti and N content is an effective way to inhibit the formation of coarse Ti(C, N) inclusions.

scholarly journals HTLV-1 AND TUBERCULOSIS ASSOCIATION: A REVIEW OF THE LITERATURE

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Normeide Pedreira dos Santos ◽  
Monique Lírio ◽  
Rita Elizabeth Moreira Mascarenhas ◽  
Leonardo Pereira Santana ◽  
Bernardo Galvão Castro ◽  
...  
Keyword(s):  
Cochrane Library ◽  
T Lymphotropic Virus ◽  
Negative Results ◽  
Size Number ◽  
Group Response ◽  
Increased Risk ◽  
The Relationship

Objective: To review and evaluate the scientific evidences on the relationship between tuberculosis (TB) and HTLV-1 infection. Methods: Searches on MEDLINE, LILACS/SciELO and Cochrane Library databases were performed using the following keywords: HTLV-1 Infection, Human T-lymphotropic virus type 1; Paraparesis Tropical Spastic; Tuberculosis. The following data were evaluated: Study design, sample size, number of controls, frequency of HTLV-1 infection in patients with TB and uninfected controls, mortality in HTLV-1/TB coinfected individuals compared with controls group, response in vivo and in vitro to PPD, frequency of individuals with tuberculin skin test (TST) positive or negative. Results: Nineteen articles were selected: twelve investigated prevalence, four mortality, three evaluated both prevalence and mortality and six described immunological findings. The majority of the studies was conducted in South America (Brazil and Peru), and Japan. Seven out of 12 studies found an increased risk of HTLV-1 in patients with TB diagnosis. The prevalence of HTLV-1/TB co-infection ranged from1.49 % in Brazil to 11.4 % in patients in Peru. Two out of five studies found a higher mortality of patients with HTLV-1/TB co-infection compared to patients with TB alone. Three studies conducted in Africa (Guinea Bissau and Senegal) found no increase in the mortality of patients co-infected with TB and HTLV-1. A decreased response to PPD in vitro or in vivo was observed in co-infected individuals compared with patients with TB alone. Conclusion: Patients with TB diagnosis have a higher prevalence of HTLV-1, compared with uninfected controls. Co-infection HTLV-1/TB increases the mortality of TB.

scholarly journals Determination of Emissivity of Brass Alloy using Infrared Thermographic Technique

2018 ◽  
Vol 65 (3) ◽  
pp. 115-121
Author(s):  
Zorana Lanc ◽  
Milan Zeljković ◽  
Aleksandar Živković ◽  
Branko Štrbac ◽  
Miodrag Hadžistević
Keyword(s):  
Surface Roughness ◽  
Regression Analysis ◽  
Multiple Regression ◽  
Strong Correlation ◽  
Three Dimensional ◽  
Multiple Regression Model ◽  
Infrared Images ◽  
Cooling Process ◽  
Brass Alloy

Abstract This paper presents the experimental determination of the dependence of emissivity of brass on surface roughness and temperature. The investigation was conducted using the infrared thermographic technique on brass alloy C27200 workpieces with different degrees of surface roughness, during the continuous cooling process. The results obtained showed that the emissivity of the chosen brass alloy increases with greater surface roughness and decreases during the cooling process, its value ranging from 0.07 to 0.19. It was concluded that surface roughness has a greater influence on the increase of the emissivity at higher temperatures, which can be seen in the three-dimensional infrared images. Multiple regression analysis confirmed a strong correlation between the examined parameters and the emissivity, and an original multiple regression model was determined.

Sign in / Sign up

Export Citation Format

Share Document