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Interfacial reactions between the electric arc furnace (EAF) slag, i.e., CaO–SiO2–FeO–MgO–Al2O3–MnO system, and the magnesia refractory as a function of direct reduced iron (DRI) addition (0, 10, 20, 30 wt%) were investigated at 1550 °C under an Ar atmosphere. MgO solubility increases with increasing DRI content by decreasing basicity (i.e., CaO/SiO2 ratio), which is due to an increase in SiO2 supplied from DRI. The measured MgO content was always lower than the theoretical MgO saturation level irrespective of DRI content because the magnesiowustite (MW) intermediate layer, which formed at the slag/refractory interface, retarded the direct dissolution of the refractory by acting as a self-protective layer. The thickness of the MW intermediate layer and dissolution depth were proportional to DRI content. However, the penetrativity decreased with increasing DRI content by decreasing the fluidity of the slag. Several kinetic parameters were estimated, including the dissolution rate constant of the MW intermediate layer, the dissolution rate of the MgO refractory, and the rate constant of MW growth. Dissolution of MgO refractory is controlled by the dissolution of the MW intermediate layer. Increasing the growth rate is very important for protecting refractory after the formation of a MW intermediate layer. In addition, we provided a schematic diagram of the slag/refractory interfacial reaction phenomena that compares situations of low and high DRI content. The results of the present study show that it is necessary to control DRI content to minimize refractory degradation during the EAF process. If a large amount of DRI must be used in the EAF process, then MgO content in the slag should be at the saturation limit at first, which accelerates growth of the MW intermediate layer.

The influence of slag composition of FeO/TiO2 (=F/T) ratio, Al2O3/(SiO2+Al2O3) (=A/(S+A)) ratio and oxygen partial pressure ( p O 2 = 10 − 10 t o 10 − 9 a t m ) on the thermodynamic behavior of vanadium oxide in molten ilmenite smelting slag, i.e., FetO-TiO2-MgO-Al2O3-SiO2 system, was investigated at 1550 °C. The distribution ratio of vanadium (= L V ) between molten iron and FetO-TiO2-MgO-Al2O3-SiO2 slag increases with increasing F/T ratio, while it decreases with increasing A/(S+A) ratio. In addition, l o g L V generally increases with increasing theoretical optical basicity of the slag (= Λ s l a g ). Vanadium oxide (VOx) is expected to behave as an acidic component in the present system. Vanadium in ilmenite smelting slags primarily consist of V3+, V4+, and V5+ ions, as determined by Gaussian deconvolution of X-ray photoelectron spectra. A linear relationship between l o g ( w t % V 4 + / w t % V 3 + ) and l o g p O 2 is confirmed. Both (wt% V3+) and (wt% V5+) ions increase with increasing F/T ratio, whereas (wt% V4+) ions show the opposite behavior with increasing F/T ratio, irrespective of A/(S+A) ratio. Meanwhile, (wt% V3+) increase while (wt% V4+) and (wt% V5+) decrease with increasing A/(S+A) ratio. The linear relationship between l o g ( w t % V 3 + / w t % V 5 + ) and l o g ( w t % V 4 + ) has a slope of 1.8, which is good agreement with the theoretical slope of 2.0, which indicates that multi-valent vanadium ion species, i.e., V3+, V4+, and V5+, are thermodynamically balanced based on redox equilibria.

The combinatorial effects of slag composition and O2-blowing conditions on silicon (Si) and iron (Fe) removal as well as gold (Au) and silver (Ag) enrichment from waste printed circuit boards (WPCBs) were investigated to optimize pyrometallurgical WPCBs recycling process. Regardless of the experimental conditions, the removal rate for Si and Fe was approximately 100%, except in slag-free operation. The Si removal rate was generally higher than the Fe removal rate at a given reaction time irrespective of experimental variables because the O2 affinity of Si is higher than that of Fe in molten copper, thermodynamically. The removal rate of impurities was clearly dependent on blowing conditions and slag composition, and a combinatorial operation of bottom-blowing and highly fluid slag favored the efficient removal of impurities. The maximum enrichment ratio of Au and Ag ( C Au , Ag Max ) was about 10% and the possession rates of Au and Ag, R Au , Ag at C Au , Ag Max were greater than 96%. The loss of Au and Ag can be minimized, i.e., R Au , Ag can be maximized by stopping O2-blowing before metal droplets are physically entrapped by molten slag, because metal droplet's entrainment is affected by slag viscosity, which contributes to the settling velocity of metal droplets. Consequently, it is very critical to appropriately control not only the slag composition but also O2-blowing conditions for both impurities removal and maximizing precious metals enrichment and possession.

Objectives The purpose of this study was to assess the occurrence, predictors, and mechanisms of optical coherence tomography (OCT)-detected coronary evaginations following drug-eluting stent (DES) implantation. Background Angiographic ectasias and aneurysms in stented segments have been associated with a risk of late stent thrombosis. Using OCT, some stented segments show coronary evaginations reminiscent of ectasias. Methods Evaginations were defined as outward bulges in the luminal contour between struts. They were considered major evaginations (MEs) when extending >= 3 mm along the vessel length, with a depth >= 10% of the stent diameter. A total of 228 patients who had sirolimus (SES)-, paclitaxel-, biolimus-, everolimus (EES)-, or zotarolimus (ZES)-eluting stents implanted in 254 lesions, were analysed after 1, 2, or 5 years; and serial assessment using OCT and intravascular ultrasound (IVUS) was performed post-intervention and after 1 year in 42 patients. Results Major evaginations occurred frequently at all time points in SES (similar to 26%) and were rarely seen in EES (3%) and ZES (2%, P = 0.003). Sirolimus-eluting stent implantation was the strongest independent predictor of ME [adjusted OR (95% CI) 9.1 (1.1-77.4), P = 0.008]. Malapposed and uncovered struts were more common in lesions with vs. without ME (77 vs. 25%, P < 0.001 and 95 vs. 20%, P < 0.001, respectively) as was thrombus [49 vs. 14%, OR 7.3 (95% CI: 1.7-31.2), P = 0.007]. Post-intervention intra-stent dissection and protrusion of the vessel wall into the lumen were associated with an increased risk of evagination at follow-up [OR (95% CI): 2.9 (1.8-4.9), P < 0.001 and 3.3 (1.6-6.9), P = 0.001, respectively]. In paired IVUS analyses, lesions with ME showed a larger increase in the external elastic membrane area (20% area change) compared with lesions without ME (5% area change, P < 0.001). Conclusion Optical coherence tomography-detected MEs are a specific morphological footprint of early-generation SES and are nearly absent in newer-generation ZES and EES. Evaginations appear to be related to vessel injury at baseline; are associated with positive vessel remodelling; and correlate with uncoverage, malapposition, and thrombus at follow-up.

Aims: Angiographic evidence of edge dissections has been associated with a risk of early stent thrombosis. Optical coherence tomography (OCT) is a high-resolution technology detecting a greater number of edge dissections -particularly non-flow-limiting- compared to angiography. Their natural history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. Methods and results: Edge dissections were defined as disruptions of the luminal surface in the 5 mm segments proximal and distal to the stent, and categorised as flaps, cavities, double-lumen dissections or fissures. Qualitative and quantitative OCT analyses were performed every 0.5 mm at baseline and one year, and clinical outcomes were assessed. Sixty-three lesions (57 patients) were studied with OCT at baseline and one-year follow-up. Twenty-two non-flow-limiting edge dissections in 21 lesions (20 patients) were identified by OCT; only two (9%) were angiographically visible. Flaps were found in 96% of cases. The median longitudinal dissection length was 2.9 mm (interquartile range [IQR] 1.6-4.2 mm), whereas the circumferential and axial extensions amounted to 1.2 mm (IQR: 0.9-1.7 mm) and 0.6 mm (IQR: 0.4-0.7 mm), respectively. Dissections extended into the media and adventitia in seven (33%) and four (20%) cases, respectively. Eighteen (82%) OCT-detected edge dissections were also evaluated with intravascular ultrasound which identified nine (50%) of these OCT-detected dissections. No stent thrombosis or target lesion revascularisation occurred up to one year. At follow-up, 20 (90%) edge dissections were completely healed on OCT. The two cases exhibiting persistent dissection had the longest flaps (2.81 mm and 2.42 mm) at baseline. Conclusions: OCT-detected edge dissections which are angiographically silent in the majority of cases are not associated with acute stent thrombosis or restenosis up to one-year follow-up.

Background The clinical manifestations of the Korean patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) are not well known. Methods The clinical data of Korean patients who met the Task Force Criteria for ARVC were analyzed. Results Thirty-seven patients (41.2±14.8 years old, 19 males) were diagnosed with ARVC. The commonest presenting symptoms were palpitations (30%), syncope/presyncope (30%) and no symptoms (30%). Four patients had a family history of premature sudden death or ARVC. Most patients with no symptoms were evaluated due to ECG abnormalities or asymptomatic ventricular arrhythmias. Ventricular tachycardia, ventricular fibrillation and frequent premature ventricular contractions only were observed in 35%, 5% and 24%, respectively. Wall motion abnormalities of the right and left ventricles were detected in 92% and 41%, respectively. Fatty or fibrofatty infiltration was observed in 26 of the 32 (81%) patients who underwent an endomyocardial biopsy. Two patients had signs of heart failure. Two patients with syncope/presyncope were diagnosed with vasovagal syncope and another was due to side effects from a medication. Most of the patients with ventricular arrhythmias were treated with β-blockers and/or amiodarone. Implantable cardioverter-defibrillators (ICDs) were implanted in 3 patients. During a mean follow-up of 27.4±26.5 months no syncope or sudden death developed except for in one patient with an ICD who suffered from recurrent shocks due to ventricular fibrillation. Conclusions ARVC may be an important cause of syncope, ventricular arrhythmias, and ECG and wall motion abnormalities of the ventricles in Koreans. The Korean patients with ARVC exhibited various clinical manifestations.