Microstructural Study of as-cast Fe-Si Alloys. Effect of Percentage of Silicon

2012 ◽  
Vol 1372 ◽  
Author(s):  
María G. González F. ◽  
José A. García H. ◽  
A. Balandra ◽  
V. Aranda.
Keyword(s):  
Morphological Changes ◽  
Electric Motors ◽  
Microstructural Study ◽  
Electrical And Magnetic Properties ◽  
Significant Difference ◽  
Solidification Pattern ◽  
Cast Alloys ◽  
Materials Used ◽  
Solidification Stage ◽  
Scanning Electron

ABSTRACTSilicon steels are materials used in construction of electric motors and transformers. Silicon is an effective element to improve the electrical and magnetic properties. During the solidification stage is defined the distribution of solute on the solid as segregation or coring. This paper researched the effect of the percentage of silicon on the microstructure and segregation profiles of the Fe-0.5wt%Si, Fe-1.5wt%Si and Fe-3wt%Si cast alloys. The samples were metallographically prepared by conventional techniques. The concentration of silicon in grain boundary regions was carried out by scanning electron microscopy (SEM) with EDS-WDS microanalysis, the morphological changes of the grain as a function of silicon was evaluated by optical microscopy. Experimental microsegregation patterns showed significant difference from the Scheil model and greater agreement with this model when considering convective-diffusive conditions. The microstructural study revealed discrepancies with the solidification pattern governed by the solidification interval.

Scanning Electron Microscopy and Roughness Study of Dental Composite Degradation

2012 ◽  
Vol 18 (2) ◽  
pp. 289-294 ◽  
Author(s):  
Luís Eduardo Silva Soares ◽  
Louise Ribeiro Cortez ◽  
Raquel de Oliveira Zarur ◽  
Airton Abrahão Martin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Roughness ◽  
Composite Resin ◽  
Morphological Changes ◽  
Soft Drink ◽  
Dental Composite ◽  
Control Group ◽  
Significant Difference ◽  
Scanning Electron

AbstractOur aim was to test the hypothesis that the use of mouthwashes, consumption of soft drinks, as well as the type of light curing unit (LCU), would change the surface roughness (Ra) and morphology of a nanofilled composite resin (Z350® 3M ESPE). Samples (80) were divided into eight groups: Halogen LCU, group 1, saliva (control); group 2, Pepsi Twist®; group 3, Listerine®; group 4, Colgate Plax®; LED LCU, group 5, saliva; group 6, Pepsi Twist®; group 7, Listerine®; group 8, Colgate Plax®. Ra values were measured at baseline, and after 7 and 14 days. One specimen of each group was prepared for scanning electron microscopy analysis after 14 days. The data were subjected to multifactor analysis of variance at a 95% confidence followed by Tukey's honestly significant difference post-hoc test. All the treatments resulted in morphological changes in composite resin surface, and the most significant change was in Pepsi Twist® groups. The samples of G6 had the greatest increase in Ra. The immersion of nanofilled resin in mouthwashes with alcohol and soft drink increases the surface roughness. Polymerization by halogen LCU (reduced light intensity) associated with alcohol contained mouthwash resulted in significant roughness on the composite.

Comparative Study of Acid Etching on Dental Enamel

2018 ◽  
Vol 69 (10) ◽  
pp. 2913-2915
Author(s):  
Daniela Jumanca ◽  
Anamaria Matichescu ◽  
Atena Galuscan ◽  
Laura Cristina Rusu ◽  
Cornelia Muntean
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Experimental Study ◽  
Orthophosphoric Acid ◽  
Dental Enamel ◽  
Acid Etching ◽  
Sealing Material ◽  
Mechanical Bond ◽  
Materials Used ◽  
Scanning Electron

This experimental study aims to analyse the effectiveness of various materials used in demineralisation of dental enamel. This work aims to create a mechanical bond by filling the pegs with sealing material. In order to achieve this goal, five teeth were compared using different concentrations of orthophosphoric acid and exposure times. In this regard, five different tests were performed and the results were analysed using the SEM technique (scanning electron microscopy). These comparative analyses revealed that etching using 35% orthophosphoric acid for one minute and etching using Icon Etch for two minutes were the most effective.

scholarly journals Scanning Electron Microscopy Analysis of the Anterior Capsulotomy Edge: A Comparative Study between Femtosecond Laser-Assisted Capsulotomy and Manual Capsulorhexis

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Daniele Tognetto ◽  
Chiara De Giacinto ◽  
Alberto Armando Perrotta ◽  
Tommaso Candian ◽  
Alessandro Bova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Femtosecond Laser ◽  
Comparative Study ◽  
Surface Irregularity ◽  
Significant Difference ◽  
Group 2 ◽  
Cut Surface ◽  
Scanning Electron ◽  
Group 1

Purpose. To compare the capsule edges ultrastructure obtained by two femtosecond laser-assisted cataract surgery (FLACS) platforms and manual continuous curvilinear capsulorhexis (CCC) using scanning electron microscopy (SEM). Setting. Eye Clinic, University of Trieste, Italy. Design. Experimental comparative study. Methods. 150 anterior capsules were collected and divided into three groups as follows: Group 1 (50 capsules) obtained with manual CCC, Groups 2 and 3 (each with 50 capsules) obtained with the Catalys Laser and the LenSx Laser, respectively. All samples were imaged by means of SEM and regularity of the cut surface, and thickness of the capsule edge were evaluated and compared. Results. All femtosecond laser (FSL) capsules were perfectly circular, whereas some alteration of the circular shape was observed in the manual ones. Group 1 showed a smooth and regular capsule edge without any surface irregularity, conversely Groups 2 and 3 showed postage-stamp perforations on the capsule edge. The cut surface irregularity value in Group 2 was 1.4 ± 0.63, while it was 0.7 ± 0.49 in Group 3 (p<0.05). Group 1 had a significantly lower thickness of the capsule edge than the FSL groups (p<0.05). No statistically significant difference in the capsule edge thickness between the FSL groups was found (p=0.244). Conclusions. Despite the presence of slight cut surface irregularities, both FSL capsulotomies showed a better geometry and circularity than the manual ones. Capsulotomy specimens obtained using both FSL capsulotomies showed laser-induced alterations of the capsule edge when compared with smooth and regular edges obtained using manual CCC.

scholarly journals Effects of Long Durations of RF–Magnetron Sputtering Deposition of Hydroxyapatite on Titanium Dental Implants

2021 ◽  
Author(s):  
Ihab Nabeel Safi ◽  
Basima Mohammed Ali Hussein ◽  
Hikmat J. Aljudy ◽  
Mustafa S. Tukmachi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Magnetron Sputtering ◽  
Dental Implants ◽  
Substrate Surface ◽  
Rf Magnetron Sputtering ◽  
P Value ◽  
Edx Analysis ◽  
Significant Difference ◽  
Scanning Electron

Abstract Objectives Dental implant is a revolution in dentistry; some shortages are still a focus of research. This study use long duration of radiofrequency (RF)–magnetron sputtering to coat titanium (Ti) implant with hydroxyapatite (HA) to obtain a uniform, strongly adhered in a few micrometers in thickness. Materials and Methods Two types of substrates: discs and root form cylinders were prepared using a grade 1 commercially pure (CP) Ti rod. A RF–magnetron sputtering device was used to coat specimens with HA. Magnetron sputtering was set at 150 W for 22 hours at 100°C under continuous argon gas flow and substrate rotation at 10 rpm. Coat properties were evaluated via field emission scanning electron microscopy (FESEM), scanning electron microscopy–energy dispersive X-ray (EDX) analysis, atomic force microscopy, and Vickers hardness (VH). Student’s t-test was used. Results All FESEM images showed a homogeneous, continuous, and crack-free HA coat with a rough surface. EDX analysis revealed inclusion of HA particles within the substrate surface in a calcium (Ca)/phosphorus (P) ratio (16.58/11.31) close to that of HA. Elemental and EDX analyses showed Ca, Ti, P, and oxygen within Ti. The FESEM views at a cross-section of the substrate showed an average of 7 µm coat thickness. Moreover, these images revealed a dense, compact, and uniform continuous adhesion between the coat layer and the substrate. Roughness result indicated highly significant difference between uncoated Ti and HA coat (p-value < 0.05). A significant improvement in the VH value was observed when coat hardness was compared with the Ti substrate hardness (p-value < 0.05). Conclusion Prolonged magnetron sputtering successfully coat Ti dental implants with HA in micrometers thickness which is well adhered essentially in excellent osseointegration.

scholarly journals Morphological Changes of the Hip Commonly Associated With Femoroacetabular Impingement Are Not Correlated With Rotational Range of Hip Motion in Elite Soccer Athletes

2021 ◽  
pp. 194173812097366
Author(s):  
André Orlandi Bento ◽  
Guilherme Falótico ◽  
Keelan Enseki ◽  
Ronaldo Alves Cunha ◽  
Benno Ejnisman ◽  
...  
Keyword(s):  
Femoroacetabular Impingement ◽  
Lower Limb ◽  
Clinical Relevance ◽  
Morphological Changes ◽  
Alpha Angle ◽  
Soccer Players ◽  
Level Of Evidence ◽  
Rotational Movement ◽  
Professional Soccer ◽  
Significant Difference

Background: Morphological changes characteristic of femoroacetabular impingement (FAI) are common in soccer players. However, the clinical relevance of such anatomical variations is still not well-defined. Hypothesis: We hypothesized that high alpha angle values and/or acetabular retroversion index (ARI) are correlated with rotational range of motion (ROM) of the hip and that there are clinical-radiological diferences between the dominant lower limb (DLL) and nondominant lower limb (NDLL) in professional soccer players. Study Design: Cross-sectional. Level of Evidence: Level 3. Methods: A total of 59 male professional soccer players (average age 25.5 years, range 18-38 years) were evaluated in the preseason. As main outcome measures, we evaluated the alpha angle and the ARI and hip IR and ER ROM with radiographic analysis. Results: The measurements taken on DLL and NDLL were compared and a significant difference was found between the sides in the ER ( P = 0.027), where the DLL measures were 1.54° (95% CI, 0.18-2.89) greater than the NDLL. There were no significant differences between the sides in the measures of IR ( P > 0.99), total ROM ( P = 0.07), alpha angle ( P = 0.250), and ARI ( P = 0.079). The correlations between the rotation measurements and the alpha angle in each limb were evaluated and the coefficient values showed no correlation; so also between the ARI and rotation measures. Conclusion: Morphological changes of the femur or acetabulum are not correlated with hip IR and ER ROM in male professional soccer players. ER on the dominant side was greater than on the nondominant side. There was no significant difference in the other measurements between sides. Clinical Relevance: In clinical practice, it is common to attribute loss of hip rotational movement to the presence of FAI. This study shows that anatomical FAI may not have a very strong influence on available hip rotational movement in professional soccer athletes.

scholarly journals Evidence for diagnosis of early chronic pancreatitis after three episodes of acute pancreatitis: a cross-sectional multicentre international study with experimental animal model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Péter J. Hegyi ◽  
Alexandra Soós ◽  
Emese Tóth ◽  
Attila Ébert ◽  
Viktória Venglovecz ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Chronic Pancreatitis ◽  
Morphological Changes ◽  
International Study ◽  
Study Data ◽  
Cross Sectional ◽  
Clinical Biomarkers ◽  
Stage Disease ◽  
Significant Difference ◽  
End Stage

AbstractChronic pancreatitis (CP) is an end-stage disease with no specific therapy; therefore, an early diagnosis is of crucial importance. In this study, data from 1315 and 318 patients were analysed from acute pancreatitis (AP) and CP registries, respectively. The population from the AP registry was divided into AP (n = 983), recurrent AP (RAP, n = 270) and CP (n = 62) groups. The prevalence of CP in combination with AP, RAP2, RAP3, RAP4 and RAP5 + was 0%, 1%, 16%, 50% and 47%, respectively, suggesting that three or more episodes of AP is a strong risk factor for CP. Laboratory, imaging and clinical biomarkers highlighted that patients with RAP3 + do not show a significant difference between RAPs and CP. Data from CP registries showed 98% of patients had at least one AP and the average number of episodes was four. We mimicked the human RAPs in a mouse model and found that three or more episodes of AP cause early chronic-like morphological changes in the pancreas. We concluded that three or more attacks of AP with no morphological changes to the pancreas could be considered as early CP (ECP).The new diagnostic criteria for ECP allow the majority of CP patients to be diagnosed earlier. They can be used in hospitals with no additional costs in healthcare.

scholarly journals Chemical and Physical Properties of Limestone Powder as a Potential Microfiller of Polymer Composites

2017 ◽  
Vol 63 (2) ◽  
pp. 67-78 ◽  
Author(s):  
M. Kępniak ◽  
P. Woyciechowski ◽  
W. Franus
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Physical Properties ◽  
Polymer Composites ◽  
Asphalt Mixture ◽  
Limestone Powder ◽  
Coarse Aggregates ◽  
Mineral Powder ◽  
Materials Used ◽  
Scanning Electron

Abstract The preliminary stage of asphalt mixture production involves the drying and dedusting of coarse aggregates. The most common types of coarse aggregates used are limestone and basalt. In the process of drying and dedusting the dryer filter accumulates large quantities of waste in the form of mineral powder. This paper introduces an investigation into limestone powder waste as a potential microfiller of polymer composites. Physical characteristics such as the granulation the of powder collected from the filter - in terms of the season of its collection and the type of input materials used - were analysed. A scanning electron microscope (SEM) was used for the investigation described within this paper. The obtained results were compared against those of other materials which can be used as polymer composites microfillers.

The Dynamics for Aqueous Sodium Adsorption and Characterization of Natural Pyrophyllite

2011 ◽  
Vol 117-119 ◽  
pp. 1129-1132
Author(s):  
Bo Liu ◽  
Hai Feng Chen ◽  
Pei Song Tang
Keyword(s):  
Qualitative Analysis ◽  
Internal Structure ◽  
Electron Micrographs ◽  
Scanning Electron Micrographs ◽  
Adsorption Dynamics ◽  
Natural Mineral ◽  
Aqueous Sodium ◽  
Materials Used ◽  
Scanning Electron

In this experiment, pyrophyllite as the main materials used the flame photometer to measure adsorption. Using the qualitative analysis of the samples of XRD with internal structure and found that pyrophyllite used in the experiment as a natural mineral, the presence with other minerals. Meanwhile, scanning electron micrographs (SEM) from the display showed that the effect of pyrophyllite adsorption for cations should be more significant. Therefore, this experiment focused on the time, Na+ concentration, on the pyrophyllite and different pyrophyllite concentrations (adsorbent dosage) effect on the adsorption, in addition to the adsorption dynamics. The results showed that pyrophyllite adsorption sodium in the best time of equilibrium was 20 minutes, the concentration of NaCl was 50 mg/L, pH = 7, temperature was 313 K, the concentration of pyrophyllite was 5 mg/L.

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