Search Results (4)

With the development of the petrochemical industry, the number of storage tanks has continuously increased, exacerbating the issue of oil evaporation losses. Therefore, it is urgent to find efficient and economical measures to reduce oil evaporation losses. This paper establishes a diffusion model for internal floating roof tanks (IFRTs) and uses numerical simulation methods to study the mass fraction distribution, pressure distribution, and the variation patterns of oil vapor inside the tanks at different floating roof heights. The results show that the closer to the top of the tank, the lower the oil vapor mass fraction, and the mass fraction distribution is almost symmetrical. As the floating roof height decreases, the vapor mass fraction in the mixed gas region inside the tank gradually decreases, showing a distribution below the lower explosive limit (LEL), indicating improved safety. Furthermore, the study found that in the benchmark model, the behavior characteristics of gasoline vapor are reflected in the changes in mass fraction, velocity, and pressure distribution, where the oil vapor concentration in the upper part is lower but evenly distributed. By comparing the behavior characteristics of oil vapor inside the tank at different floating roof heights, it was found that the floating roof height significantly affects the diffusion and accumulation of oil vapor. The presence of vents effectively reduces the accumulation of oil vapor concentration, improving the stability and safety inside the tank. For different floating roof height scenarios (such as CASE 1, CASE 2, and CASE 4), the oil vapor behavior characteristics are similar. The study results provide important theoretical support for the future development of oil vapor recovery technologies and the design of enclosed energy-saving recovery devices inside tanks, indicating that optimizing the floating roof height and vent system design can significantly reduce oil evaporation losses. Full article

(1) Background: This study aimed to examine the difference in efficacy and toxicity of involved-field (IFRT) and involved-site radiotherapy (ISRT) fields in infradiaphragmal aggressive non-Hodgkin lymphoma patients. (2) Methods: In total, 140 patients with infradiaphragmal lymphoma treated between 2003 and 2020 were retrospectively evaluated. There were 69 patients (49%) treated with IFRT, and 71 (51%) patients treated with ISRT. The median dose in the IFRT group was 36 Gy, (range 4–50.4 Gy), and in the ISRT group, it was 30 Gy (range 4–48 Gy). (3) Results: The median follow-up in the IFRT group was 133 months (95% CI 109–158), and in the ISRT group, it was 48 months (95% CI 39–57). In the IFRT group, locoregional control was 67%, and in the ISRT group, 73%. The 2- and 5-year overall survival (OS) in the IFRT and ISRT groups were 79% and 69% vs. 80% and 70%, respectively (p = 0.711). The 2- and 5-year event-free survival (EFS) in the IFRT and ISRT groups were 73% and 68% vs. 77% and 70%, respectively (p = 0.575). Acute side effects occurred in 43 (31%) patients, which is more frequent in the IFRT group, 34 (39%) patients, than in the ISRT group, 9 (13%) patients, p > 0.01. Late toxicities occurred more often in the IFRT group of patients, (10/53) 19%, than in the ISRT group of patients, (2/37) 5%, (p = 0.026). (4) Conclusions: By reducing the radiotherapy volume and the doses in the treatment of infradiaphragmatic fields, treatment with significantly fewer acute and long-term side effects is possible. At the same time, efficiency and local disease control are not compromised. Full article

Radiation therapy has been proven to be highly effective in the treatment of lymphoma. With increasing rates of long-term survival, the reduction in toxicity has gained importance. The evolving understanding of the diseases’ biology, as well as technical and conceptual advances, allows for a precise and individualized application of irradiation. Smaller treatment fields and safety margins make it possible to spare healthy neighbouring tissue (organs at risk). The International Lymphoma Radiation Oncology Group (ILROG) has developed several guidelines to optimize radiotherapy treatment in lymphoma patients. Since its introduction in 2013, involved site radiotherapy (ISRT) has been adopted as the standard of care in most treatment regimens in adult lymphoma. This article serves as a summary of the current ILROG guidelines, also considering contemporary developments and possible future directions. Full article

Internal floating-roof tanks (IFRTs) are widely used to store light oil and chemical products. However, if the annular-rim gap around the floating deck becomes wider due to abrasion and aging of the sealing arrangement, the static breathing loss from the rim gap will be correspondingly aggravated. To investigate the oil-vapor migration and emissions from an IFRT, the effects of varying both the floating-deck height and wind speed on the oil-vapor diffusion were analyzed by performing numerical simulations and wind-tunnel experiments. The results demonstrate that the gas space volume and the wind speed of an IFRT greatly influence the vapor-loss rate of the IFRT. The larger the gas space volume, the weaker the airflow exchange between the inside and outside of the tank, thereby facilitating oil-vapor accumulation in the gas space of the tank. Furthermore, the loss rate of the IFRT is positively correlated with wind speed. Meanwhile, negative pressures and the vortexes formed on the leeward side of the tank. In addition, the higher concentration areas were mainly on the three vents on the downwind side of the IFRT. The results can provide important theoretical support for the design, management, and improvement of IFRTs. Full article