Effect of R Angle of the Outer Extension Tube against the in-Core Flux Thimble in Nuclear Power Plant on Its Wear Behavior

Wear failure of the in-core flux thimble is an important problem in the neutron flux measurement system, which threatens the safety of the nuclear power plant. To figure out the wear mechanism of the thimble, a wear tester was designed and manufactured to simulate the wear process of the in-core flux thimble. Outer guide tubes with different R angles were used to abrade the thimbles. The designed tester can well simulate the wear process in the real power plant. R angle of the outer guide tube played important role in the wear behavior of the in-core flux thimbles.

Research of Acoustically Improved Helmholtz Resonator

The three-dimensional acoustic finite element method is used to predict the transmission loss of the Helmholtz resonance muffler. The results are in good agreement with the experimental results, indicating the applicability and accuracy of the numerical method used in this paper. On the one hand, in order to reduce the resonance frequency without changing the shape of the resonator, the connecting tube is extended to the inside of the resonator, and the influence of the extension length and the cross section shape of the extension tube on the acoustic characteristics of the resonator is discussed in detail. On the other hand, in order to broaden the muffled frequency band of the traditional Helmholtz resonators, the resonators are combined in series and parallel, and the influence of the combined structure on the acoustic characteristics is discussed in detail.

Duodenal Decubitus Ulcer Caused by Percutaneous Endoscopic Transgastric Jejunostomy Tube

Percutaneous endoscopic gastrostomy (PEG) has substituted surgical gastrostomy for long-term enteral nutrition. Percutaneous endoscopic transgastric jejunostomy (PEG-J) entails placing a feeding tube into the jejunum through PEG. Unlike PEG, PEG-J is associated with complications caused by the jejunal extension tube. Herein, we report a rare complication of PEG-J. A 71-year-old woman who underwent PEG-J for the administration of carbidopa-levodopa, complained of epigastric pain, dyspepsia, and weight loss of more than 10% in 2 months. Esophagogastroduodenoscopy revealed a duodenal decubitus ulcer caused by the pressure from the jejunal extension tube. After removal of the PEG-J and a 4-week treatment with a proton pump inhibitor, the ulcer healed and the symptoms resolved.

Novel Choices of Cannula for Blood Delivery via Femoral Artery in Pediatric Patients

We previously presented a cardiopulmonary bypass (CPB) method with blood delivery via femoral artery cannulation for pediatric aortic arch repair operations using the Radifocus Introducer sheath. However, the flow rate with the Radifocus Introducer sheath is limited by accessory parts with the same structure having a smaller inner diameter among different sizes, rather than the sheath body. Therefore, we further devised a combination of the JELCO IV catheter, an extension tube, and a three-way stopcock with a larger opening to obtain more flow rate keeping the CPB circuit pressure significantly lower than when using the Radifocus Introducer sheath successfully.

An autonomous economical and efficient ureteroscopic irrigation system

Background In recent years, the minimally invasive technique for treating nephrolithiasis has been developed rapidly. Particularly, the flexible ureteroscopy has been extensively applied. For flexible ureteroscopy lithotripsy, the perfusion equipment is necessary to ensure a clear intraoperative field of view. This study was aimed to prepare a set of economical and efficient ureteroscopic irrigation system by some commonly used devices in clinical diagnosis and treatment practice. Methods In this study, according to requirements of the endoscopic surgery, the infusion apparatus, infusion apparatus extension tube, three-way plug valve, Luer one-way valve, ordinary syringe, and negative pressure spring were used to assemble the irrigation system with different functions. Results The autonomous perfusion device realized the real-time conversion of manual injection, continuous perfusion or negative pressure suction. The entire equipment has many advantages, including easily accessible raw materials, low cost, simple assembly process, easy operation, strong controllability, effective control ability for the intrarenal pressure, and high safety. Conclusions The commonly used medical devices were applied to assemble the autonomous ureteroscopic irrigation system, which is flexible, simple and cost-effective and thus can be applied in flexible ureteroscopic surgery.

Evaluation of Mixing Uniformity for Inline Mixers by Image Processing

HighlightsFour inline mixers with different structures are designed and tested for DNIS applications.A new method for evaluating inline mixing uniformity by image processing is presented.While higher carrier flow rates cause better uniformity, changes due to higher mixing ratios are complicated.The multi-injection jet mixer has simplified structure and relatively satisfactory mixing efficacy.Abstract. Effective and specialized mixing devices that can achieve pesticide injection and inline mixing simultaneously are required to achieve better mixing efficacy in direct nozzle injection systems (DNISs), especially when high-viscosity pesticides are used. To evaluate the inline mixing efficacies of four inline mixers with different structures under various application conditions and to propose optimized structures for those inline mixers, a new method for evaluating uniformity based on image processing is presented. The results of experiments show that the proposed method is adequate for determining mixing uniformity. The mixing uniformity of each mixer increased with carrier flow rates (Q) ranging from 800 to 2,000 mL min-1, but the variations were less significant than those achieved by varying the mixing ratio (P) from 1:100 to 10:100. The mixing uniformity in the jet mixer (mixer A) clearly decreased with an increase in P at different values of Q because the pesticide gradually concentrated on one side of the detection tube. The layered mixer (mixer B) performed better than mixer A, especially at high P. The extension tube installed downstream of mixer B to improve uniformity was shorter than that of mixer A. Mixer C, whose structure was a combination of mixers A and B, had optimal mixing efficacy and the most complicated structure. The uniformity of the multi-injection jet mixer (mixer D) (Haverage = 12.46) obtained by simplifying mixer C was superior to that of mixers A (Haverage = 15.35) and B (Haverage = 14.65) but inferior to that of mixer C (Haverage = 4.08). With a relatively simple structure, mixer D may generally meet the uniformity requirements, thus resulting in advantages for practical use in DNISs, although further structural optimization of mixer D seems necessary. Keywords: Direct nozzle injection system, Image processing, Inline mixers, Mixing uniformity, Principal component analysis, Various application conditions.

A bent needle tip during irrigation for enchondroma of the distal phalanx: a new curettage tool

Background We employed a novel curettage tool, a bent needle tip, during irrigation for enchondroma of the distal phalanx. This study aimed to evaluate our new curettage tool for treating enchondroma of the distal phalanx. Methods Seven distal phalanx enchondromas were pathologically diagnosed at our institute. We evaluated age, gender, tumor location, affected side, clinical symptoms, Takigawa classification, size, recurrence, complications, residual pain, Tordai score, and follow-up period. We bent an 18G needle tip connected to an extension tube and syringe. The bent needle was inserted through the small hole, and the cavity for bone grafting was adequately filled with injectable calcium phosphate cement through the small hole. Results There were five centric-type and two giant-type tumors, with a mean size of 52.7%. All patients had clinical symptoms at the initial presentation. All patients showed complete bone healing within 3 months on post-radiological examinations and were Grade 1 according to the Tordai score. Conclusions This tool is extremely simple, and both the incision and the cortical window can be small. We recommend a bent needle tip, easily devised in any hospital, as a curettage tool for treating enchondroma in small bones, especially of the distal phalanx.

Pre-operative direct puncture embolization of head and neck hypervascular tumors using SQUID 12

Objective The authors have evaluated their experience in pre-operative direct puncture embolization of hypervascular tumors of the head and neck using SQUID 12, an embolic liquid agent. Methods Between July 2016 and March 2019, the authors retrospectively reviewed clinical, embolization and surgical data of 11 consecutive patients with 12 hypervascular head and neck tumors who had undergone pre-operative embolization using SQUID 12. Percutaneous embolizations were performed by inserting a 19-22 Gauge needle directly into the tumor under ultrasound, fluoroscopic and/or endoscopic guidance. The hub of the needle was connected to a 15-cm DMSO-compatible extension tube, and the SQUID 12 was injected. Results Total or near-total devascularization was achieved in 11 over 12 cases. Complete en-bloc tumor removal by surgery was achieved in all cases. Only one patient required blood transfusion. No major periprocedural adverse events were recorded. Conclusions Direct puncture embolization of hypervascular tumors of the head and neck using SQUID 12 seems to be safe and effective. It may offer almost complete devascularization due to homogenous, deep penetration in the tumor, with optimal visibility of the agent throughout the percutaneous procedure. It may reduce intraoperative blood loss and the need for transfusion, thus facilitating complete surgical resection.