Slug length estimation for gas-liquid slug flow in T-shaped microdevices with liquid film

13th IFAC Symposium on Dynamics and Control of Process Systems, including Biosystems DYCOPS 2022, Busan, Republic of Korea, 14–17 June 2022To realize stable long-term operation of microdevices with gas-liquid slug flow, the slug lengths have to be monitored and controlled, because they influence mass transfer performance. In this study, an experimental investigation was carried out to analyze the gas-liquid slug flow in a T-shaped microdevice with a liquid film. The experimental result showed that the pressures in gas and liquid feeding tubes oscillate periodically along the formation of a pair of gas and liquid slugs. Then, the correlation equation between the liquid film thickness and the number of capillaries was identified on the basis of the experimental data. Based on these results, a method for estimating slug lengths and liquid film thickness from measurements of feed pressure and feed flowrate was developed. The developed method is non-invasive and does not affect slug formation or the manner of gas-liquid slug flow. Its effectiveness was assessed through an experimental case study, and the relative root mean square errors of estimated slug lengths were within 8.5%. The result show that the developed method can be applied to the monitoring of slug lengths

Combination Chemotherapy with Low-dose 5-FU, Cisplatin, and Gemcitabine for Gemcitabine-Refractory Pancreatic Cancer

Background : No single agent or combination therapy for advanced pancreatic cancer has been reported superior to single-agent GEM, and an effective second-line chemotherapy option is needed for patients who are resistant to first-line GEM therapy. Methods :We analyzed six patients who had disease progression following first-line gemcitabine therapy. Patients received second-line chemotherapy with low dose cisplatin, 5-fluorouracul or S-1,and gemcitabine every 21 days. Results : Two patients showed a partial response (33.3%) and two showed stable disease. Four patients (66.6%) showed a prolonged survival time with partial responses or stable disease.Median survival times were 7 and 11 months from the start of second-line therapy and the start of first-line gemcitabine therapy,respectively. In addition, all patients reported relief from pain and had a favorable performance status. The major toxicities of leucopenia, stomatitis, and diarrhea were found in one patient each.Conclusion : This second-line chemotherapy regimen is an effective option for patients with gemcitabineresistant pancreatic cancer.Article信州医学雑誌 57(6): 247-253(2009)journal articl

Mechanisms of Lower Bile Duct Stricture in Autoimmune Pancreatitis

Objectives We attempted to clarify the mechanism underlying lower bile duct stricture in autoimmune pancreatitis. Methods Imaging and histologic finding of the bile duct were assessed for 73 patients with autoimmune pancreatitis to clarify whether IgG4-related biliary inflammation or pancreatic head swelling is associated with lower bile duct stricture. Results Lower bile duct stricture was found in 59 (81%) patients. Pancreatic head swelling was significantly more frequent among patients with lower bile duct stricture than those patients without lower bile duct stricture (53 [90%] vs 4 [29%]; P < 0.01). Intraductal ultrasonography findings revealed lower bile duct wall thickening in 21 (95%) of the 22 patients with lower bile duct stricture, and the lower bile duct wall of the patients with pancreatic head swelling was significantly thicker than those patients without pancreatic head swelling (P = 0.028). Among the 38 patients with lower bile duct biopsies, 14 (37%) exhibited abundant IgG4-bearing plasma cell infiltration. Among the patients with lower bile duct stricture, an IgG4-related inflammation seemed to exert a dominant effect under limited conditions, including concomitant middle bile duct stricture and neither pancreatic swelling nor pancreatic duct stricture in the head region. Conclusions Both pancreatic head swelling and IgG4-related biliary inflammation affect lower bile duct stricture, which may be included in IgG4-related sclerosing cholangitis. Pancreatic head swelling affects IgG4-related biliary wall thickening.ArticlePANCREAS. 43(2):255-260 (2014)journal articl

Amendment of the Japanese Consensus Guidelines for Autoimmune Pancreatitis, 2013 II. Extrapancreatic lesions, differential diagnosis

Published online: 25 March 2014ArticleJOURNAL OF GASTROENTEROLOGY. 49(5):765-784 (2014)journal articl

Operation policy for micro chemical plants with external numbering-up structure

Microreaction Technology IMRET 9: Proceedings of the Ninth International Conference on Microreaction Technology - IMRET9 Special IssueOne of the critical operational issues of micro chemical plants with external numbering-up structure is to keep a uniform flow distribution among parallelized microdevices even when blockage occurs in one or more microdevice. Since it is not practical to install flow controllers in all the microdevices, a simple and effective operation policy against blockage occurrence needs to be developed. In this research, micro chemical plants having four or eight parallelized microdevices are constructed to analyze the influence of blockage on the flow distribution among the parallelized microdevices. The numerical and experimental results show that pressure drop control is superior to total flow control. In addition, two control structures based on pressure drop control, pumping pressure control and pressure drop control over the parallelized section, are investigated. It is clarified that the latter control structure enables us to successfully keep the flow rate in each unblocked microdevice at a normal level when blockage occurs. Pressure drop control over the parallelized section is applied to a micro chemical plant having four parallelized micro heat exchangers, and its validity is demonstrated

Optimal channel design and sensor placement in flow distributors for detecting blockage of parallelized microreactors

When the production capacity of micro chemical plants is increased by numbering-up approach, it is important to realize the uniform flow distribution among the parallelized microreactors. In addition, a blocked microreactor needs to be identified as early as possible to achieve the stable long-term operation of micro chemical plants. In this research, a system that can detect a blocked microreactor by using just two flow sensors is developed. The performance of the developed system is maximized by adjusting the channel size and sensor placement in the flow distributors. The effectiveness of the developed system and the optimal design result is demonstrated by computational fluid dynamics simulation