Search results for: G. M. Najmul Quader

Authors: Raf E. Ul Shougat, Ezazul Haque Sabuz, G. M. Najmul Quader, Monon Mahboob

Abstract:

Since there are lots of ways for building and post processing of parts or models in 3D printing technology, the main objective of this research is to provide an understanding how mechanical characteristics of 3D printed parts get changed for different building orientations and infiltrates. Tensile, compressive, flexure, and hardness test were performed for the analysis of mechanical properties of those models. Specimens were designed in CAD software, printed on Z-printer 450 with five different build orientations and post processed with four different infiltrates. Results show that with the change of infiltrates or orientations each of the above mechanical property changes and for each infiltrate the highest tensile strength, flexural strength, and hardness are found for such orientation where there is the lowest number of layers while printing.

Keywords: 3D printing, building orientations, infiltrates, mechanical characteristics, number of layers

Procedia PDF Downloads 259

Authors: Najmul Hasan, Shiping Li, Chunli Liu

Abstract:

The synergy effect of surface modifications using the acid treatment and noble metal (Au) deposition on the efficiency of SnFe2O4 (SFO) nano-octahedron photocatalyst has been investigated. Inorganic acids (H2SO4 and HNO3) were employed to compare the effects of different acids. It has been found that after corrosion treatment using H2SO4 and deposition of Au nanoparticles, SnFe2O4 nano-octahedron (Au-S-SFO) showed significantly enhanced photocatalytic activity under simulated light irradiation. Au-S-SFO was characterized by XRD, XPS, EDS, FTIR, Uv-vis-DRS, SEM, PL, and EIS analysis. The mechanism for CO2 reduction was investigated by scavenger tests. The stability of Au-S-SFO was confirmed by continuously repeated tests followed by XRD analysis. The surface corrosion treatment of SFO octahedron with H2SO4 could produce hydroxyl group (-OH) and sulfonic acid group (-SO3H) as reaction sites. These active sites not only enhanced the Au nanoparticles deposition to the acid treated SFO surface but also acted as the Brønsted acid sites that enhance the water adsorption and provide protons for CTC degradation and CO2 reduction. These effects improved the carrier separation and transfer efficiency. In addition, the photocatalytic efficiency was further enhanced by the surface plasmon resonance (SPR) effect of Au nanoparticles deposited on the surface of acid-treated SFO. As a result of the synergy of both acid treatment and SPR effect from the Au NPs, Au-S-SFO exhibited the highest CO2 reduction activity with 2.81, 1.92, and 2.69 times higher evolution rates for CO, CH4, and H2, respectively than that of pure SFO.

Keywords: surface modification, CO2 reduction, Au deposition, Gas-liquid interfacial plasma

Procedia PDF Downloads 59

Authors: Abdul Aziz, Muhammad Qamar Masood, Saadia Sattar, Saira Fatima, Najmul Islam

Abstract:

Introduction: The most common endocrine tumor is thyroid cancer. Follicular Thyroid Carcinoma (FTC) accounts for 5%–10% of all thyroid cancers. Patients with FTC frequently present with more advanced stage diseases and a higher occurrence of distant metastases because of the propensity of vascular invasion. FTC is mainly treated with surgery, while radioactive iodine therapy is the main adjuvant therapy as per ATA guidelines. In many developing countries, surgical facilities and radioactive iodine are in short supply; therefore, understanding follicular thyroid cancer trends may help developing countries plan and use resources more effectively. Methodology: It was a retrospective observational study of FTC patients of age 18 years and above conducted at Aga Khan University Hospital, Karachi, from 1st January 2010 to 31st December 2019. Results: There were 404 patients with thyroid carcinoma, out of which forty (10.1%) were FTC. 50% of the patients were in the 41-60 years age group, and the female to male ratio was 1.5: 1. Twenty-four patients (60%) presented with complain of neck swelling followed by metastasis (20%) and compressive symptoms (20%). The most common site of metastasis was bone (87.5%), followed by lung (12.5%). The pre-operative thyroglobulin level was done in six out of eight metastatic patients (75%) in which it was elevated. This emphasizes the importance of checking thyroglobulin level in unusual presentation (bone pain, fractures) of a patient having neck swelling also to help in establishing the primary source of tumor. There was no complete documentation of ultrasound features of the thyroid gland in all the patients, which is an important investigation done in the initial evaluation of thyroid nodule. On FNAC, 50% (20 patients) had Bethesda category III-IV nodules, while 10% ( 4 patients ) had Bethesda category II. In sixteen patients, FNAC was not done as they presented with compressive symptoms or metastasis. Fifty percent had a total thyroidectomy and 50% had subtotal followed by completion thyroidectomy, plus ten patients had lymph node dissection, out of which seven had histopathological lymph node involvement. On histopathology, twenty-three patients (57.5%) had minimally invasive, while seventeen (42.5%) had widely invasive follicular thyroid carcinoma. The capsular invasion was present in thirty-three patients (82.5%); one patient had no capsular invasion, but there was a vascular invasion. Six patients' histopathology had no record of capsular invasion. In contrast, the lymphovascular invasion was present in twenty-six patients (65%). In this study, 65 % of the patients had clinical stage 1 disease, while 25% had stage 2 and 10% had clinical stage 4. Seventeen patients (42.5%) had received RAI 30-100 mCi, while ten patients (25%) received more than 100 mCi. Conclusion: FTC demographic and clinicopathological presentation are the same in Pakistan as compared to other countries. Surgery followed by RAI is the mainstay of treatment. Thus understanding the trend of FTC and proper planning and utilization of the resources will help the developing countries in effectively treating the FTC.

Keywords: thyroid carcinoma, follicular thyroid carcinoma, clinicopathological features, developing countries

Procedia PDF Downloads 158