Potential of IGCC slag as an alkali activated material

Integrated gasification combined cycle (IGCC) is a next generation energy production technology that converts coal into syngas with enhanced power generation efficiency and environmental performance. IGCC produces coal gasification slag as the solid by-product. Recycling of IGCC slag is still in the early stages, but the recycling process has been around the cement and concrete industry. We calculated the reactive Si/Al ratio of IGCC slag which is generated from a pilot plant in South Korea, and evaluated the potential of it as an alkali-activated material. Samples which were activated with the combined activator of sodium silicate solution and caustic soda had an average compressive strength of 4.5 MPa, showing swelling on the top free surface. Expansion of the alkali-activated slag was possibly caused by free CaO and MgO in the slag. While the samples that were activated with the combined activator of sodium aluminate and caustic soda had an average compressive strength of 10 MPa. Hydroxy sodalite and C3AH6 were found to be the new crystalline phases. IGCC slag can be used as an alkali-activated material, but the strength performance should be improved with proper mix design approach which can alleviate the expansion issue at the same time. Acknowledgement This study was supported by Korea Western Power Co., Ltd. in South Korea

Successful Treatment of Tracheal Stenosis with Slide Tracheoplasty after the Failure of Resection with End-to-End Anastomosis

The combined effects of inhaled irritant gases and heat in burn patients can result in the development of laryngotracheal strictures. Several factors could adversely affect the development of tracheal stenosis and cause the growth of granulation tissue. Yet the current treatment options for this condition are limited because of the paucity of case reports. We report here on a case of a patient who experienced recurrent upper tracheal stenosis after an inhalation injury. She displayed repetitive symptoms of stenosis even after several laryngomicrosurgeries and resection with end-to-end anastomosis. Finally, 5 yr after the burn injury, slide tracheoplasty was successfully performed and the postoperative check-up findings and the increased airway volume seen on imaging were all satisfactory

Endoscopic Thyroidectomy via an Axillo-Breast Approach without Gas Insufflation for Benign Thyroid Nodules and Micropapillary Carcinomas: Preliminary Results

PURPOSE: To examine the feasibility of endoscopic thyroidectomy (ET) via an axillo- breast approach without gas insufflation for large thyroid tumors and micropapillary carcinomas. MATERIALS AND METHODS: The patients in the benign group were separated into groups 1 (n=95, <4 cm in tumor diameter) and 2 (n=37, ≥4 cm in tumor diameter). Also, 57 patients in the micropapillary carcinoma group underwent an endoscopic hemithyroidectomy (HT) (group 3) and were compared with 60 patients who received conventional open HT (group 4). Postoperative functional outcome, local complications, surgical outcomes, and pathological outcomes were compared between the groups. RESULTS: In the benign group, there was no significant difference in mean operating time, hospital stay, or overall perioperative complications between the two groups. In the micropapillary carcinoma group, mean operating time and hospital stay in group 3 were significantly longer than in group 4 (p=0.015 and p≤0.001). The overall perioperative complications did not differ significantly between the groups. The postoperative cosmetic result was better in groups 1-3 (endo group) than in group 4 (open group). CONCLUSION: ET via a gasless axillo-breast approach seems to be a safe procedure even for benign thyroid lesions ≥4 cm and micropapillary carcinomas. Although it has the advantage of better cosmetic results over open thyroidectomy, there is room for improvement in terms of lessening its invasiveness and shortening the operative time.ope

Schwannoma in Head and Neck: Preoperative Imaging Study and Intracapsular Enucleation for Functional Nerve Preservation

PURPOSE: In treating schwannoma patients, it is critical to determine the origin of the tumor to preserve nerve function. We evaluated the validity of preoperative imaging studies in distinguishing the neurological origin of the schwannomas of the head and neck, and the efficacy of intracapsular enucleation in preserving nerve function. MATERIALS AND METHODS: In 7 cases of schwannomas in the head and neck region, we predicted whether the tumor originated from the vagus nerve or the cervical sympathetic chain through imaging studies including computed tomography (CT) and magnetic resonance imaging (MRI). All patients were performed intracapsular enucleation, and the function of the vagus nerve and the sympathetic nerve was evaluated preoperatively and postoperatively. RESULTS: Preoperative imaging studies showed 6 cases where the tumor was located between the carotid artery and the internal jugular vein, and 1 case where the tumor was located posteriorly, displacing the carotid artery and the internal jugular vein anteriorly. At the time of operation, we confirmed schwannoma originating from the vagus nerve on the first 6 cases, and schwannoma originating from the sympathetic nervous system on the last case. All patients went through successful intracapsular enucleation, and of the seven schwannoma cases, 6 patients maintained normal postoperative neurological function (85.7%). CONCLUSION: Preoperative imaging studies offer valuable information regarding the location and origination of the tumor, and intracapsular enucleation helped us to preserve the nerve function.ope