Effects of eustachian tube function in outcome of graft in tympanoplasty or tympanomastoidectomy for chronic otitis media1

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Malakooti B

2000-07-01

Full Text Available Chronic otitis media is a common disease which can lead to serious complications or even death. Betterment of eustachian tube function is effective on results of operations. The main goal of this study was to determine the effect of eustachian tube function on outcome of graft in tympanoplasty or tympanomastoidectomy for chronic otitis media. We prospectively studied 126 patients who underwent these operations in Amir Alam hospital in 1998. Eustachian tube function, technique of operation, use of silastic, age, sex, presence of cholesteatoma were evaluated in each patient and graft vascularization after 6 to 8 weeks of surgery was considered as successful outcome. Among 126 ears, 59 had good ETF and among those 59 ears 88.1% or 52 had successful outcome. Among 67 patients with poor ETF 46 or 68.7% got successful results. This significant difference shows the role of Eustachian tube function on the result of surgery.

Treatment of middle ear ventilation disorders: sheep as animal model for stenting the human Eustachian tube--a cadaver study.

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Felicitas Miller

Full Text Available Eustachian tube disorders can lead to chronic otitis media with consecutive conductive hearing loss. To improve treatment and to develop new types of implants such as stents, an adequate experimental animal model is required. As the middle ear of sheep is known to be comparable to the human middle ear, the dimensions of the Eustachian tube in two strains of sheep were investigated. The Eustachian tube and middle ear of half heads of heathland and blackface sheep were filled with silicone rubber, blended with barium sulfate to induce X-ray visibility. Images were taken by digital volume tomography. The tubes were segmented, and a three-dimensional model of every Eustachian tube was generated. The lengths, diameters and shapes were determined. Additionally, the feasibility of endoscopic stent implantation and fixation was tested in cadaver experiments. The length of the tube between ostium pharyngeum and the isthmus and the diameters were comparable to published values for the human tube. The tube was easily accessible through the nose, and then stents could be implanted and fixed at the isthmus. The sheep appears to be a promising model for testing new stent treatments for middle ear ventilation disorders.

Functional MR imaging of the Eustachian tube in patients with clinically proven dysfunction: correlation with lesions detected on MR images

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Luekens, Anna; Guenther, Rolf W. [University Hospital, University of Technology (RWTH) Aachen, Department of Diagnostic Radiology, Aachen (Germany); DiMartino, Ercole [Ev. Diakonie-Krankenhaus, Department of Otolaryngology and Head- and Neck-Surgery, Bremen (Germany); Krombach, Gabriele A. [University Hospital, University of Technology (RWTH) Aachen, Department of Diagnostic Radiology, Aachen (Germany); University Hospital Giessen, University Giessen, Department of Diagnostic and Interventional Radiology, Giessen (Germany)

2012-03-15

To visualise the function of the Eustachian tube by MRI and assess the effect of surrounding lesions. Using 1.5 T MRI, 32 Eustachian tubes of 16 patients with clinically proven dysfunction (clinical symptoms, such as autophonia and fullness and non-opening at tympanometry) were investigated. For depiction of the anatomy and associated abnormalities, coronal and axial T2-weighted turbo spin echo sequences and a T1-weighted-2D-gradient echo sequences were acquired. Eustachian tube opening was analysed with real time turbo-gradient echo sequences during a Valsalva manoeuvre. Dysfunction, that is, failure of opening of the Eustachian tube as shown by MRI, correlated in all patients with tympanometry. Lesions detected included nasopharyngeal carcinoma in 4 patients. Mucosal swelling in the paranasal sinus was present in 9 patients. One patient had postoperative defects. In two patients both pharyngotympanic tubes did not open although no structural abnormalities could be depicted. The opening of the Eustachian tubes during the Valsalva manoeuvre is assessable on MRI. Failure of opening may be due to swelling of the mucosa and may be also associated with tumours. MRI assessment may be helpful in patients with chronic otitis media, where the information about tubal function is important in preoperative planning. (orig.)

Balloon dilation of the eustachian tube in a cadaver model: technical considerations, learning curve, and potential barriers.

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McCoul, Edward D; Singh, Ameet; Anand, Vijay K; Tabaee, Abtin

2012-04-01

The surgical management options for eustachian tube dysfunction have historically been limited. The goal of the current study was to evaluate the technical considerations, learning curve, and potential barriers for balloon dilation of the eustachian tube (BDET) as an alternative treatment modality. Prospective preclinical trial of BDET in a cadaver model. A novel balloon catheter device was used for eustachian tube dilation. Twenty-four BDET procedures were performed by three independent rhinologists with no prior experience with the procedure (eight procedures per surgeon). The duration and number of attempts of the individual steps and overall procedure were recorded. Endoscopic examination of the eustachian tube was performed after each procedure, and the surgeon was asked to rate the subjective difficulty on a five-point scale. Successful completion of the procedure occurred in each case. The overall mean duration of the procedure was 284 seconds, and a mean number of 1.15 attempts were necessary to perform the individual steps. The mean subjective procedure difficulty was noted as somewhat easy. Statistically shorter duration and subjectively easier procedure were noted in the second compared to the first half of the series, indicating a favorable learning curve. Linear fissuring within the eustachian tube lumen without submucosal disruption (nine procedures, 37%) and with submucosal disruption (five procedures, 21%) were noted. The significance of these physical findings is unclear. Preclinical testing of BDET is associated with favorable duration, learning curve, and overall ease of completion. Clinical trials are necessary to evaluate safety and efficacy. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

[A case of petrous ridge meningioma manifested as pneumocephalus followed by Eustachian tube insufflation].

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Yamaguchi, Shinya; Gi, Hidefuku; Uno, Jyunji; Ikai, Yoshiaki; Inoha, Satoshi; Nagaoka, Shintarou; Nishio, Shunji

2009-05-01

A 50-year-old female, who had a headache after Eustachian tube insufflation for her ear congestion, came to our hospital. CT and MRI revealed pneumocephalus and petrous ridge meningioma which destroyed petrous bone and air cells. Eustachian tube insufflation was considered to make the air coming into the middle ear, mastoid air cell and then into the intracranial space destroying the tumor. At surgery, there was subdural hematoma around the tumor. Total removal of the tumor and the hematoma membrane was performed. Histologically, the tumor was transitional meningioma and the cluster of meningioma cells were noted in the subdural hematoma membrane.

Study the Effect of Nasal Obstruction Surgery (Septoplasty on Eustachian Tube Function and Middle Ear Pressure

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Rahim Davari

2014-12-01

Full Text Available Background & objectives: Deviation of the nasal septum is a common cause of unilateral or bilateral nasal airway obstruction and may follow nasal and midface trauma. Patient complaints of airway obstruction that are consistent with intranasal physical findings often lead to septoplasty and turbinate surgery. Severe nasal septal deviation leads to complete nasal obstruction and disturbs air passage from nostrils, however the effect of septal deviation and nasal obstruction surgery (septoplasty on Eustachian tube function and middle ear pressure is controversial and isn’t clear. Whereas many of surgeons do not believe the considerable effect of septoplasty on Eustachian tube function and middle ear pressure, so they do not recommend this procedure before middle ear surgery. On the other hand, some have an idea that septoplasty has significant effect on middle ear pressure suggesting this procedure before ear surgery like tympanoplasty.   Methods: This prospective analytical-descriptive study was conducted on seventy patients from 18 to 65 years of age who underwent septoplasty due to severe septal deviation leading to nasal obstruction in Beesat Hospital during one year (2012-2013. Middle ear pressure and Eustachian tube function on the septal deviated side and contralateral side before and after septoplasty (3 to 6 months later were measured through tympanometry and Eustachian tube function test (Toynbee test. The comparison between pre- and postoperative ETF tests and middle ear pressures was assessed using Paired –T test and p-value of less than 0.05 was considered as statistically significant.   Results : This study revealed that comparison between mean values of pressure in the deviated and contralateral side has no significant statistical difference before and after septoplasty. Also comparison between Eustachian function in the deviated side and contralateral side showed no significant difference before and after septoplasty. �

Middle Ear Pressure Regulation - Complementary Action of the Mastoid and Eustachian Tube

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Gaihede, Michael; Dirckx, Joris J J; Jacobsen, Henrik

2010-01-01

, MEP counter-regulation presented as Eustachian tube openings with steep and fast pressure changes toward 0 Pa, whereas in others, gradual and slow pressure changes presented related to the mastoid; these changes sometimes crossed 0 Pa into opposite pressures. In many cases, combinations...... to continuous regulation of smaller pressures, whereas the tube was related to intermittent regulation of higher pressures....

Middle Ear Pressure Regulation - Complementary Action of the Mastoid and Eustachian Tube

DEFF Research Database (Denmark)

Gaihede, Michael; Jacobsen, Henrik; Tveterås, Kjell

, MEP counter-regulation presented as Eustachian tube openings with steep and fast pressure changes toward 0 Pa, whereas in others, gradual and slow pressure changes presented related to the mastoid; these changes sometimes crossed 0 Pa into opposite pressures. In many cases, combinations...... to continuous regulation of smaller pressures, whereas the tube was related to intermittent regulation of higher pressures....

The evaluation of the angles of Eustachian tubes in the patients with chronic otitis media on the temporal computerized tomography.

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Aksoy, S; Sayin, I; Yazici, Z M; Kayhan, F T; Karahasanoglu, A; Hocaoglu, E; Inci, E

2016-01-01

Chronic otitis media (COM), affecting all over the world and in a wide range of age groups in Turkey, is an important cause of ear discharge and hearing loss. The main clinical manifestations are tympanic membrane perforation, ear, nose and throat problems. On the tympanic membrane perforation becomes persistent and cholesteatoma development, there are a lot of opinions today. Especially in the pathology associated with otitis media with effusion eustachian tube, it is known that COM and cholesteatoma develop. In our study, we interpreted 210 patients' temporal computed tomography (CT). Seventy of these 210 patients had otitis media with cholesteatoma, 70 patients had only otitis media without cholesteatoma, and 70 patients had no otitis media. The eustachian tubes were evaluated using temporal CT multiplanar reconstruction method. Angles with the horizontal plane of the eustachian tube and Reid and tubotympanic angles were measured. The angles between eustachian tube and horizontally oriented Reid plane of the patients with cholesteatoma were found to be significantly lower than the patients with otitis media without cholesteatoma and the patients with no history of otitis media. For the tubotympanic angle, no statistically significant differences were observed between the groups. These results suggest that the decrease in the angle with the horizontal plane of Reid in the eustachian tube in adults may play a significant role in the etiology of cholesteatoma.

[The observation and analysis the function and morphology of the eustachian tube in secretory otitis media and chronic rhinosinusitis in children].

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Xia, Zhongfang; Wang, Zhinan; Xu, Zhongxiang; Cui, Long; Wei, Cuifen; Liu, Yan; Huang, Fang

2014-07-01

To observe and analyze the function and morphology of pharyngeal ostium of the eustachian tubes in secretory otitis media and chronic rhinosinusitis in children under direct vision,in order to provide an objective basis for clinical treatments. Fifty cases of secretory otitis media,50 cases of chronic rhinosinusitis and a control group of 50 cases with hoarseness were examined under video laryngoscope to observe the pharyngeal ostium morphological changes of the eustachian tubes, and their functional statuses were tested by using acoustic impedance instrument. All the data were analyzed by statistical methods. (1) In the secretory otitis group, the abnomal rate of the pharyngeal ostium of the eustachian tubes was 94% while the chronic rhinosinusitis group was 80%,and between them there was no significant differences (P > 0.05). But both of them had significant differences with the control group (P otitis group, the rate of the eustachian tube dysfunction was 70% while the chronic rhinosinusitis group was 26%, and between them there was significant differences (P otitis media and chronic rhinosinusitis in children. Eustachian tube dysfunction played a dominant role in the pathogenesis of secretory otitis media in children rather than the morphological change did compared to the chronic rhinosinusitis in children.

The evaluation of the angles of Eustachian tubes in the patients with ...

African Journals Online (AJOL)

2015-12-02

Dec 2, 2015 ... plane is considered to be the position at which the head in a neutral anatomical ..... Proctor B. Embryology and anatomy of the eustachian tube. Arch Otolaryngol. 1967 ... Otolaryngol Head Neck Surg. 1986;94:78‑81. 22.

Measurement of the viscoelastic compliance of the eustachian tube using a modified forced-response test.

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Ghadiali, Samir N; Federspiel, William J; Swarts, J Douglas; Doyle, William J

2002-01-01

Eustachian tube compliance (ETC) was suggested to be an important determinate of function. Previous attempts to quantify ETC used summary measures that are not clearly related to the physical properties of the system. Here, we present a new method for measuring ETC that conforms more closely to the engineering definition of compliance. The forced response test was modified to include oscillations in applied flow after the forced tubal opening. Pressure and flow were recorded during the standard and modified test in 12 anesthetized cynomolgus monkeys. The resulting pressure-flow, hysteresis loops were compared with those predicted by a simple fluid-structure model of the Eustachian tube with linear-elastic or viscoelastic properties. The tubal compliance index (TCI) and a viscoelastic compliance (C(v)) were calculated from these data for each monkey. The behavior of a viscoelastic, but not a linear elastic model accurately reproduced the experimental data for the monkey. The TCI and C(v) were linearly related, but the shared variance in these measures was only 63%. This new method for measuring ETC captures all information contained in the traditional TCI, but also provides information regarding the contribution of wall viscosity to Eustachian tube mechanics.

The evaluation of the angles of Eustachian tubes in the patients with ...

African Journals Online (AJOL)

Materials and Methods: In our study, we interpreted 210 patients' temporal computed tomography (CT). Seventy of these 210 patients had otitis media with cholesteatoma, 70 patients had only otitis media without cholesteatoma, and 70 patients had no otitis media. The eustachian tubes were evaluated using temporal CT ...

Comparison between the angle of Eustachian tube in patients with chronic suppurative otitis media and normal ears based on computed tomography scan of temporal bones in Haji Adam Malik general hospital Medan

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Masita, S.; Zahara, D.; Aboet, A.

2018-03-01

The function of the Eustachian tube plays a significant role in increased risk chronic suppurative otitis media (CSOM). The angle of the Eustachian tube is a predisposing factor for Eustachian tube dysfunction and clearance disorder of the middle ear. The aim of this study was to compare the mean angle of a Eustachian tube of CSOM ears and normal ears. This research was a cross-sectional study consisting of 19 patients of CSOM without cholesteatoma, 19 patients of CSOM with cholesteatoma and 19 patients with normal ears. All patients were examined using CT Temporal, and the angle of the eustachian tube was measured using multiplanar reconstruction technique. The mean angle of Eustachian tube in CSOM patients without cholesteatoma was 32.82° (SD=3.82), in CSOM with cholesteatoma was 27.74° (SD=4.44) and in normal ears was 33.61° (SD=3.83). Based on Kruskal-Wallis test, there was a significant difference in the angle of a Eustachian tube of these three groups (p<0.001). There was a significant difference between the mean angle of the Eustachian tube in CSOM ears and normal ears.

Tuboimpedance: A New Test of Eustachian Tube Function.

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Smith, Matthew E; Zou, Charlie C; Blythe, Andrew J C; Tysome, James R

2017-04-01

Objective Eustachian tube (ET) dysfunction is most frequently caused by a failure of the ET to adequately open; however, there is currently no reliable method of assessing this. Tubomanometry has recently shown good interindividual repeatability as a measure of ET function by measuring middle ear pressure after the application of regulated nasopharyngeal pressures during swallowing. We present the first reports of a novel test: middle ear impedance measurements during standard nasopharyngeal pressure application (tuboimpedance). We assess repeatability in healthy ears and any advantages over tubomanometry. Study Design Exploratory cohort diagnosis study. Setting Tertiary referral center. Subjects Twenty screened, healthy ears (10 volunteers). Methods Tubomanometry and tuboimpedance tests were performed while individuals swallowed with applied nasopharyngeal pressures of 20, 30, 40, and 50 mbar. Eustachian tube opening detection rate and test repeatability (measured by intraclass correlation coefficient [ICC]) for immediate and delayed repeats at each pressure were compared. Results ET opening was detected more frequently using tuboimpedance, with a 100% detection rate using a nasopharyngeal pressure of 30 mbar or more, compared to 88% to 96% with tubomanometry. Detection of ET opening at 20 mbar was possible with tuboimpedance. Repeatability of both tests was mostly strong (ICC >0.7) for both immediate and delayed repeats. Repeatability for the tubomanometry R value was only fair to moderate. Conclusion Tuboimpedance may provide a repeatable measure of ET opening that is easier to perform due to lower nasopharyngeal pressures required and fewer issues with poor ear-probe sealing. Further assessment in patients with different forms of ET dysfunction is required.

Fluoroscopy-guided balloon dilation in patients with Eustachian tube dysfunction

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Kim, Kun Yung; Tsauo, Jiaywei; Song, Ho-Young [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Park, Hong Ju; Kang, Woo Seok [University of Ulsan College of Medicine, Department of Otorhinolaryngology-Head and Neck Surgery, Asan Medical Center, Seoul (Korea, Republic of); Park, Jung-Hoon [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); University of Ulsan College of Medicine, Department of Biomedical Engineering Research Center, Asan Medical Center, Seoul (Korea, Republic of); Wang, Zhe [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Tianjin Medical University General Hospital, Department of Radiology (China)

2018-03-15

To prospectively evaluate the technical feasibility and safety of fluoroscopy-guided balloon dilation in patients with Eustachian tube (ET) dysfunction. Patients who could not do a Valsalva manoeuvre for more than 6 months and diagnosed with chronic otitis media or ET dysfunction were prospectively enrolled. A 0.035-in. guide wire and 6-mm long balloon catheter with a diameter of 2 mm were used to dilate the cartilaginous portion of the ET under fluoroscopic guidance. The balloon was inflated by manual injection twice for 1 min each time. Clinical outcomes were assessed by the patient's ability to perform a Valsalva manoeuvre, and symptoms were assessed using the 7-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7) score. Balloon dilation was attempted in a total of ten adult patients from October 2016 to March 2017. Technical success was achieved in all procedures (10/10). Ninety percent (9/10) of the balloons were fully dilated without waist deformity. There were no major complications. All patients were able to perform a Valsalva manoeuvre at the time of their last visit and/or improvement of at least one ETDQ-7 score. Fluoroscopy-guided balloon dilation seems to be technically feasible and safe in the treatment of ET dysfunction. (orig.)

The effect of endoscopic sinus surgery on symptoms of eustachian tube dysfunction.

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Stoikes, Nathaniel F N; Dutton, Jay M

2005-01-01

The symptom of eustachian tube dysfunction has been categorized as a "minor" symptom in chronic rhinosinusitis. The aim of this pilot study was to determine the frequency of otologic symptoms in patients with confirmed rhinosinusitis and the likelihood of its resolution in those patients undergoing endoscopic sinus surgery (ESS). Questionnaires were obtained from 168 patients who had undergone prior ESS over a 5-year period. Patients were asked to evaluate if they suffered from several different potential symptoms of eustachian tube dysfunction before ESS and whether that symptom changed postoperatively. Using the binomial test, 95% confidence intervals were determined for the following otologic symptoms of tubal dysfunction: "earfullness and congestion," "ear cracking and popping," "dizziness," and "ear pain. "ESS was found to have a significant treatment effect for the indicated otologic symptoms of tubal dysfunction. Tubal dysfunction, as manifested by otologic symptoms, is common in patients with chronic rhinosinusitis undergoing ESS. The classification of this as a "minor" symptom of rhinosinusitis needs to be reevaluated. These symptoms improve or resolve in the majority of patients undergoing ESS.

An Eustachian Tube Neuroendocrine Carcinoma: A Previously Undescribed Entity and Review of the Literature

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Gavin J. le Nobel

2016-01-01

Full Text Available Primary sinonasal and middle ear neuroendocrine carcinomas are rare malignancies of the head and neck. Owing to the rarity of these tumors, the clinical behavior and optimal management of these tumors are not well defined. We present a case of an incidentally discovered sinonasal neuroendocrine carcinoma that was found to originate from the Eustachian tube, which has not previously been described in the literature. This patient was treated with primary surgical resection using a combination of transnasal and transaural approaches and achieved an incomplete resection. Follow-up imaging demonstrated continued tumor growth in the Eustachian tube as well as a new growth in the ipsilateral cerebellopontine angle and findings suspicious of perineural invasion. However, the tumor exhibited a benign growth pattern and despite continued growth the patient did not receive additional treatment and he remains asymptomatic 35 months following his original surgery.

First branchial cleft fistula presenting with internal opening on the Eustachian tube: Illustrated cases and literature review.

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Liu, Yuhe; Li, Tiancheng; Xue, Junfang; Jia, Jun; Xiao, Shuifang; Zhao, Enmin

2012-05-01

Two cases of first branchial cleft fistula with internal opening on the Eustachian tube are reported and the diagnosis, management and embryological hypothesis are discussed. Retrospective study and review of the literature. Both patients were young boys with first branchial cleft anomaly clearly identified by computed tomography fistulography scan and direct Methylene Blue dye injection. In both cases, surgical removal revealed a fistula with internal opening located on the Eustachian tube near the nasopharynx. The main embryological theories and classification are reviewed. A connection between the theories of first branchial apparatus development and the classification by Work might explain the reported clinical association. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Myringotomy versus ventilation tubes in secretory otitis media: eardrum pathology, hearing, and eustachian tube function 25 years after treatment

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Caye-Thomasen, P.; Stangerup, S.E.; Jorgensen, G.

2008-01-01

OBJECTIVE: This report documents the dynamics of eardrum pathology, hearing acuity, and eustachian tube function during 25 years after treatment of bilateral secretory otitis media. The included children were treated by myringotomy on the left ear and ventilation tube insertion on the right ear....... MATERIALS AND METHODS: Two hundred twenty-four children with bilateral secretory otitis media were treated by bilateral myringotomy and insertion of a ventilation tube on the right side only. The children were reexamined by otomicroscopy, tympanometry, and pure tone audiometry after 3, 7, and 25 years...

Tensor tenopexy: a clinical study to assess its effectiveness in improving Eustachian tube function and preventing hearing loss in patients with cleft palate.

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Tiwari, Raja; Sharma, Ramesh K; Panda, Naresh K; Munjal, Sanjay; Makkar, Surinder

2013-09-01

There is a consensus about the occurrence of otitis media in children with cleft palate before repair. However, controversy continues regarding the recovery of Eustachian tube function and level of hearing loss in the patients after cleft palate repair. Levator sling palatoplasty is an important component of the cleft repair. Most surgeons would routinely transect the tensor tendon (tensor tenotomy) during the course of palatoplasty. However, this procedure may pose a risk to Eustachian tube function. Some authorities feel that addition of tensor tenopexy during palatoplasty would maintain the Eustachian tube in an open conformation, thereby improving middle ear ventilation. The present study assesses the effectiveness of tensor tenopexy in improving Eustachian tube function and preventing hearing loss in cleft palate patients treated with palatoplasty. A prospective randomised controlled trial was conducted in the Department of Plastic Surgery at a tertiary care institute in India. A total of 17 children in the age group of 9-24 months were assigned to one of two groups: palatoplasty with either tensor tenotomy (n = 8) or tensor tenotomy with tensor tenopexy (n = 9). All patients were subjected to tympanometry, otoscopy and brainstem evoked response audiometry before surgery and at 3, 6, 9 and 12 months after surgery. Of these, 52.9% of patients already had hearing loss at the time of presentation. Hearing loss and middle ear effusion persisted even after palatoplasty. There was no significant difference in hearing loss and middle ear effusion between the two groups of patients. Thus, tensor tenopexy was not found to be helpful in maintaining Eustachian tube function or preventing hearing loss in cleft palate patients. However, further long-term studies are needed to confirm this study. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

[Balloon dilatation of the cartilaginous portion of the Eustachian tube in the children presenting with relapsing exudative otitis media].

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Burova, O V; Bogomil'sky, M R; Polunin, M M; Soldatsky, Yu L

2016-01-01

The objective of the present study was to evaluate the effectiveness and the safety of balloon dilatation of the cartilaginous portion of the Eustachian tube in the children presenting with relapsing exudative otitis media. A total of 15 children (22 ears) at the age from 3 to 16 years suffering from relapsing exudative otitis media over 18 months in duration were available for the examination. Neither conservative nor surgical treatment produced any stable beneficial effect in these patients. Acoustic impedancometry yielded type B tympanograms. All the children were treated with the use of balloon dilatation of the cartilaginous portion of the Eustachian tube under endotracheal anesthesia. The follow-up examination carried out within 6--8 weeks after the treatment revealed the complete recovery of the function of the middle ear (type A tympanograms) in 11 (73.3%) children. Partial restoration of this function (as evidenced by type C tympanogram) was documented in 4 children. These patients underwent the second course of conservative therapy that resulted in the complete restoration of the function of the middle ear. It is concluded that balloon dilatation of the cartilaginous portion of the Eustachian tube in the children presenting with relapsing exudative otitis media provides the efficient and safe approach to the management of this condition. Being a minimally invasive method, it has good prospects for the practical application and is worth further investigation.

Evidence and evidence gaps in the treatment of Eustachian tube dysfunction and otitis media

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Teschner, Magnus

2016-01-01

Evidence-based medicine is an approach to medical treatment intended to optimize patient-oriented decision-making on the basis of empirically proven effectiveness. For this purpose, a classification system has been established to categorize studies – and hence therapy options – in respect of associated evidence according to defined criteria. The Eustachian tube connects the nasopharynx with the middle ear cavity. Its key function is to ensure middle ear ventilation. Compromised ventilation results in inflammatory middle ear disorders. Numerous evidence-based therapy options are available for the treatment of impaired middle ear ventilation and otitis media, the main therapeutic approach being antibiotic treatment. More recent procedures such as balloon dilation of the Eustachian tube have also shown initial success but must undergo further evaluation with regard to evidence. There is, as yet, no evidence for some of the other long-established procedures. Owing to the multitude of variables, the classification of evidence levels for various treatment approaches calls for highly diversified assessment. Numerous evidence-based studies are therefore necessary in order to evaluate the evidence pertaining to existing and future therapy solutions for impaired middle ear ventilation and otitis media. If this need is addressed, a wealth of implications can be expected for therapeutic approaches in the years to come. PMID:28025605

Balloon Eustachian Tuboplasty in children.

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Leichtle, A; Hollfelder, D; Wollenberg, B; Bruchhage, K-L

2017-06-01

Endonasal ballon dilatation of the Eustachian tube (BET) is a promising treatment for Eustachian tube dysfunction with encouraging results over the last years in adults. In addition, in children, single studies demonstrated promising results, but revealed the necessity for broader and additional studies. Our retrospective analysis presents outcomes with BET in children with chronic obstructive dysfunction of the Eustachian tube, showing resistance to the conventional therapy after adenotomy with paracentesis or grommets (ventilation tubes). The data of 52 children, having undergone BET from April 2011 to April 2016, were retrospectively evaluated. Most children in our study presented middle ear effusion (47%), adhesive (21%), chronic otitis media (13%), or recurrent acute otitis media (11%). In 24 (37%) children, we combined BET with a paracentesis, in 5 (8%) patients with a tympanoplasty type I and in 3 (5%) patients with a type III. All children were assessed using an audiogram, tympanometry, and tubomanometry (50 mbar) before and after BET. In addition, we evaluated the results of the Lübecker questionnaire, which we performed before and after BET. The childrens' ear-related and quality of life-related symptoms, such as pressure equalization, ear pressure, hearing loss, pain and limitation in daily life, and satisfaction pre- and postoperatively, were analyzed. In the majority of patients, we could see an improvement in the ear pressure, hearing loss, limitation in daily life, and satisfaction with recurrent inflammations, underlined by better outcomes in the tubomanometry and the tympanogram. BET in children is a safe, efficient, and promising method to treat chronic tube dysfunction, especially as a second line treatment, when adenotomy, paracentesis, or grommets failed before.

Changes in microvascular permeability of the middle ear mucosa following the occulsion of the eustachian tube of rabbits

International Nuclear Information System (INIS)

Kikuchi, Yasutaka

1988-01-01

Serial changes in submucosal microvascular permeability of the middle ear and the response to histamine after occlusion of the eustachian tube were functionally investigated using radioisotope in rabbits with experimentally induced otitis media with effusion. Tritium water was administered through intravenous injection and transference of tritium water into the middle ear cavity was measured by radioactivity of the middle ear perfusate. Morphological changes were concurrently examined for comparison. Vascular permeability, as measured one, 7, and 14 days after occlusion of the eustachian tube, increased with time. A histological study showed an edematous hypertrophy of the submucosal tissue of the middle ear, suggesting a noticeable increase in microvascular permeability. The response of the middle ear mucosa to histamine, which was added to the fluid for perfusion, gradually decreased after occlusion of the eustachian tube, although the effect of histamine tended to persist for a long time, irrespective of the amount of administration. The results indicated that the mucosal membrane of the middle ear has a noticeable permeability at least up to 14 days after occlusion, and that histamine may be responsible for the increase of submucosal microvascular permeability not only in the normal middle ear cavity but also in otitis media with effusion which results in the persistance of the disease. The presence of factors permeable to the blood, other than histamine, caused microvascular peameability to increase, probably resulting in chronic or irreversible inflammation. This may be explained by markedly proliferative or parenchymatous connective tissues observed 7 and l0 weeks after occlusion. It should be noted that surgical treatment be performed as early as possible in the case of otitis media with effusion. (Namekawa, K) 80 refs

Retrospective results of radiation therapy of the Eustachian tube in chronic otitis media

International Nuclear Information System (INIS)

Schultze, J.; Reinke, C.; Kimmig, B.; Frese, K.A.

2003-01-01

Background: The treatment results of symptomatic radiation therapy of the Eustachian tube in chronic otitis media had to be evaluated retrospectively. Patients and Methods: Between 1980 and 1997, 66 patients were referred for therapy. The median age was 58 years. In the clinical presentation, all the patients had a hearing impairment, 35 patients complained of pain, 21 had otorrhea. In their history, 20 patients indicated chronic recurrent infections. The complaints lasted for 4.7 years in the median, primary conservative (adstringentia, antibiotics) and surgical treatment (paracentesis, tympanic tubule, tympanoplastic) did not lead to lasting cure. In 40 of 66 patients, finally radiation therapy was done of both Eustachian tubes. With opposed fields and cobalt-60 photons a total dose of 6 Gy at single doses of 1 Gy, three times a week, was applied. Under the causes for exclusion of radiation therapy were non-acceptance of the patients (nine), prior radiation therapies (six) or spontaneous improvement after initial presentation in our department. The treatment results were evaluated by interviews of the patients and regular otorhinolaryngological examinations. Results: There were no side effects noticed. 28 of 40 (70%) patients reported a significant improvement that could be verified by objective otorhinolaryngological examinations. In the group of 26 nonirradiated patients, 22 could be interviewed indicating in 16 cases (72%) that the complaints were unchanged and chronic otitis media was lasting. In a subgroup analysis concerning the duration of otitis media radiation therapy proved more effective in an acute and subacute stadium of disease of up to 5 years duration, while the patients resistant to radiation therapy were entirely in a chronic stage of disease exceeding 5 years duration. (orig.) [de

Involvement of pterygoid venous plexus in patulous eustachian tube symptoms.

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Oshima, Takeshi; Ogura, Masaki; Kikuchi, Toshiaki; Hori, Yoko; Mugikura, Shunji; Higano, Shuichi; Takahashi, Shoki; Kawase, Tetsuaki; Kobayashi, Toshimitsu

2007-07-01

The pterygoid venous plexus (PVP) is an important factor in the mechanism of eustachian tube (ET) closure under conditions that can cause increased venous pressure in the head, such as during neck compression and postural change from the sitting/standing to the recumbent position. The symptoms of patulous ET are usually improved by neck compression or postural change (from sitting/standing to recumbent position). Venous congestion around the ET and/or gravitational change may be involved in the changing degree of symptoms, but its mechanism is not understood. This study investigated whether the PVP is involved. The dimensions of soft tissues surrounding ET were measured on magnetic resonance images before and after neck compression. The lateral pterygoid muscle became enlarged after neck compression. Simultaneously, the volume of venous plexus observed between the medial pterygoid muscle and tensor veli palatini muscle was increased. Such enlargement was probably due to blood pooling in the PVP, resulting in protrusion of the ET anterior wall to the luminal side, and decreased ET patency.

Eustachian tube diameter: Is it associated with chronic otitis media development?

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Paltura, Ceki; Can, Tuba Selçuk; Yilmaz, Behice Kaniye; Dinç, Mehmet Emre; Develioğlu, Ömer Necati; Külekçi, Mehmet

To evaluate the effect of ET diameter on Chronic Otitis Media (COM) pathogenesis. Retrospective. Patients with unilateral COM disease are included in the study. The connection between fibrocartilaginous and osseous segments of the Eustachian Tube (ET) on axial Computed Tomography (CT) images was defined and the diameter of this segment is measured. The measurements were carried out bilaterally and statistically compared. 154 (76 (49%) male, 78 (51%) female patients were diagnosed with unilateral COM and included in the study. The mean diameter of ET was 1947mm (Std. deviation±0.5247) for healthy ears and 1788mm (Std. deviation±0.5306) for diseased ears. The statistical analysis showed a significantly narrow ET diameter in diseased ear side (p<0.01). The dysfunction or anatomical anomalies of ET are correlated with COM. Measuring of the bony diameter of ET during routine Temporal CT examination is recommended for our colleagues. Copyright © 2017 Elsevier Inc. All rights reserved.

Identifying eustachian tube dysfunction prior to hyperbaric oxygen therapy: Who is at risk for intolerance?

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Cohn, Jason E; Pfeiffer, Michael; Patel, Niki; Sataloff, Robert T; McKinnon, Brian J

Determine whether specific risk factors, symptoms and clinical examination findings are associated with hyperbaric oxygen therapy (HBOT) intolerance and subsequent tympanotomy tube placement. A retrospective case series with chart review was conducted from 2007 to 2016 of patients undergoing HBOT clearance at a tertiary care university hospital in an urban city. Eighty-one (n=81) patient charts were reviewed for risk factors, symptoms and clinical examination findings related to HBOT eustachian tube dysfunction and middle ear barotrauma. Relative risk was calculated for each variable to determine risk for HBOT intolerance and need for tympanotomy tube placement. Risk factor, symptom, physical examination and HBOT complication-susceptibility scores were calculated for each patient. Mean risk factor, clinical and HBOT complication-susceptibility scores were significantly higher in patients who did not tolerate HBOT compared to patients who tolerated HBOT. Patients reporting a history of otitis media, tinnitus, and prior ear surgery were at a higher risk for HBOT intolerance. Patients reporting a history of pressure intolerance and prior ear surgery were more likely to undergo tympanotomy tube placement. Patients noted to have otologic findings prior to HBOT were at a higher risk for both HBOT intolerance and tympanotomy tube placement. A thorough otolaryngological evaluation can potentially predict and identify patients at risk for HBOT intolerance and tympanotomy tube placement. Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of xylomethazoline on eustachian tube function in healthy participants.

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Meyer, Moritz F; Mikolajczak, Stefanie; Korthäuer, Christine; Jumah, Masen D; Hahn, Moritz; Grosheva, Maria; Lüers, Jan-Christoffer; Hüttenbrink, Karl-Bernd; Beutner, Dirk

2015-06-01

The use of decongestants is common in otitis media eustachian tube (ET) dysfunction. However, the underlying mechanism and the type of action on the complex middle ear pressure equalization system are poorly understood. Here, by use of the pressure chamber, we investigated the impact of intranasal decongestive therapy (xylomethazoline) on ET function. Thirty healthy participants (60 ears) were exposed to a predetermined profile of phases of compression and decompression in a hypobaric and hyperbaric pressure chamber. ET opening pressure, ET opening duration, ET opening frequency, and ET closing pressure were determined before and after intranasal application of xylomethazoline. A significantly higher number of ET openings (ET opening frequency) in passive equalization condition could be measured after application of decongestants than before. No significant difference could be found in the values of ET opening pressure, ET opening duration, and ET closing pressure parameters before in comparison with the values after application of xylomethazoline. We conclude that xylomethazoline might only have a minor effect during active and passive middle ear pressure equalization. Larger cohorts and targeted application of decongestants should be tested to confirm these preliminary data and to find new evidence on the effects of decongestants.

Characterizing the active opening of the eustachian tube in a hypobaric/hyperbaric pressure chamber.

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Mikolajczak, Stefanie; Meyer, Moritz Friedo; Hahn, Moritz; Korthäuer, Christine; Jumah, Masen Dirk; Hüttenbrink, Karl-Bernd; Grosheva, Maria; Luers, Jan Christoffer; Beutner, Dirk

2015-01-01

Active and passive opening of the Eustachian tube (ET) enables direct aeration of the middle ear and a pressure balance between middle ear and the ambient pressure. The aim of this study was to characterize standard values for the opening pressure (ETOP), the opening frequency (ETOF), and the opening duration (ETOD) for active tubal openings (Valsalva maneuver, swallowing) in healthy participants. In a hypobaric/hyperbaric pressure chamber, 30 healthy participants (19 women, 11 men; mean age, 25.57 ± 3.33 years) were exposed to a standardized profile of compression and decompression. The pressure values were recorded via continuous impedance measurement during the Valsalva maneuver and swallowing. Based on the data, standard curves were identified and the ETOP, ETOD, and ETOF were determined. Recurring patterns of the pressure curve during active tube opening for the Valsalva maneuver and for active swallowing were characterized. The mean value for the Valsalva maneuver for ETOP was 41.21 ± 17.38 mbar; for the ETOD, it was 2.65 ± 1.87 seconds. In the active pressure compensation by swallowing, the mean value for the ETOP was 29.91 ± 13.07 mbar; and for the ETOD, it was 0.82 ± 0.53 seconds. Standard values for the opening pressure of the tube and the tube opening duration for active tubal openings (Valsalva maneuver, swallowing) were described, and typical curve gradients for healthy subjects could be shown. This is another step toward analyzing the function of the tube in compression and decompression.

Eustachian tube function and middle ear barotrauma associated with extremes in atmospheric pressure.

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Miyazawa, T; Ueda, H; Yanagita, N

1996-11-01

Eustachian tube (ET) function was studied by means of sonotubometry and tubotympano-aerodynamography (TTAG) prior to and following exposure to hypobaric or hyperbaric conditions. Forty normal adults were subjected to hypobaric pressure. Fifty adults who underwent hyperbaric oxygen (HBO) therapy also were studied. Following hypobaric exposure, 14 of 80 ears (17.5%) exhibited middle ear barotrauma. Following hyperbaric exposure, 34 of 100 ears (34%) exhibited middle ear barotrauma. Dysfunction of the ET, characterized by altered active and passive opening capacity, was more prevalent following exposure to extremes in atmospheric pressure compared to baseline. The ET function, which was impaired after the first HBO treatment, improved gradually over the next 2 hours. Overall, however, ET function was worse after the seventh treatment. The patients who developed barotrauma exhibited worse ET function prior to hypobaric or hyperbaric exposure. Thus, abnormal ET function can be used to predict middle ear barotrauma prior to exposure to hypobaric or hyperbaric atmospheric pressure.

Tobacco Smoke Exposure and Eustachian Tube Disorders in US Children and Adolescents.

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Mira A Patel

Full Text Available To describe the association between active, environmental tobacco smoke (ETS exposure and the prevalence of eustachian tube dysfunction (ETD in the U.S. pediatric population.Cross-sectional.U.S. representative demographic and audiometric data from the National Health and Nutrition Examination Survey (NHANES;2005-2010.The study consisted of 2,977 children aged 12-19 years. ETD was defined as middle ear pressure <100mm H20. ETS was defined as non-active smoking in individuals with serum cotinine over the limit of detection (≥0.015 ng/mL and <10 ng/mL(N = 1559.The prevalence of ETD was 6.1%. After multivariate adjustment for age, sex, body mass index, education level, ethnicity, or having a cold, sinus problem or earache during the last 24 hours, compared to unexposed children, the odds ratios (95% confidence interval of ETD for those exposed to ETS ages 12-15 in the first, second and third tertile of cotinine concentrations were, respectively, 1.38 (0.53-3.60, 0.99 (0.53-3.60 and 2.67 (1.12-6.34. Similarly, the odds ratios (95% confidence interval of ETD for those exposed to ETS ages 16-19 in the first, second and third tertile of cotinine concentrations were, respectively, 1.28 (0.48-3.41, 0.99 (0.40-2.48 and 2.86 (1.19-6.88.These data suggest that children and adolescents exposed to high concentrations of ETS may have an increased prevalence of ETD.

Assessment of Eustachian tube function in patients with tympanic membrane retraction and in normal subjects.

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Canali, Inesângela; Petersen Schmidt Rosito, Letícia; Siliprandi, Bruno; Giugno, Cláudia; Selaimen da Costa, Sady

The diagnosis of Eustachian tube dysfunctions is essential for better understanding of the pathogenesis of chronic otitis media. A series of tests to assess tube function are described in the literature; however, they are methodologically heterogeneous, with differences ranging from application protocols to standardization of tests and their results. To evaluate the variation in middle ear pressure in patients with tympanic membrane retraction and in normal patients during tube function tests, as well as to evaluate intra-individual variation between these tests. An observational, contemporary, cross-sectional study was conducted, in which the factor under study was the variation in middle ear pressure during tube function tests (Valsalva maneuver, sniff test, Toynbee maneuver) in healthy patients and in patients with mild and moderate/severe tympanic retraction. A total of 38 patients (76 ears) were included in the study. Patients underwent tube function tests at two different time points to determine pressure measurements after each maneuver. Statistical analysis was performed using SPSS software, version 18.0, considering p-values <0.05 as statistically significant. Mean (standard deviation) age was 11 (2.72) years; 55.3% of patients were male and 44.7% female. The prevalence of type A tympanogram was higher among participants with healthy ears and those with mild retraction, whereas type C tympanograms were more frequent in the moderate/severe retraction group. An increase in middle ear pressure was observed during the Valsalva maneuver at the first time point evaluated in all three groups of ears (p=0.012). The variation in pressure was not significant either for the sniff test or for the Toynbee maneuver at the two time points evaluated (p≥0.05). Agreement between measurements obtained at the two different time points was weak to moderate for all tests in all three groups of ears, and the variations in discrepancy between measurements were higher in ears

Ear Tubes

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... of the ear drum or eustachian tube, Down Syndrome, cleft palate, and barotrauma (injury to the middle ear caused by a reduction of air pressure, ... specialist) may be warranted if you or your child has experienced repeated ... fluid in the middle ear, barotrauma, or have an anatomic abnormality that ...

Reliability of Eustachian tube function measurements in a hypobaric and hyperbaric pressure chamber.

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Meyer, M F; Jansen, S; Mordkovich, O; Hüttenbrink, K-B; Beutner, D

2017-12-01

Measurement of the Eustachian tube (ET) function is a challenge. The demand for a precise and meaningful diagnostic tool increases-especially because more and more operative therapies are being offered without objective evidence. The measurement of the ET function by continuous impedance recording in a pressure chamber is an established method, although the reliability of the measurements is still unclear. Twenty-five participants (50 ears) were exposed to phases of compression and decompression in a hypo- and hyperbaric pressure chamber. The ET function reflecting parameters-ET opening pressure (ETOP), ET opening duration (ETOD) and ET opening frequency (ETOF)-were determined under exactly the same preconditions three times in a row. The intraclass correlation coefficient (ICC) and Bland and Altman plot were used to assess test-retest reliability. ICCs revealed a high correlation for ETOP and ETOF in phases of decompression (passive equalisation) as well as ETOD and ETOP in phases of compression (active induced equalisation). Very high correlation could be shown for ETOD in decompression and ETOF in compression phases. The Bland and Altman graphs could show that measurements provide results within a 95 % confidence interval in compression and decompression phases. We conclude that measurements in a pressure chamber are a very valuable tool in terms of estimating the ET opening and closing function. Measurements show some variance comparing participants, but provide reliable results within a 95 % confidence interval in retest. This study is the basis for enabling efficacy measurements of ET treatment modalities. © 2017 John Wiley & Sons Ltd.

Effect of terfenadine on nasal, eustachian tube, and pulmonary function after provocative intranasal histamine challenge.

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Skoner, D P; Doyle, W J; Boehm, S; Fireman, P

1991-12-01

Previous studies have documented that intranasal histamine challenge results in nasal and eustachian tube obstruction (ETO) in human volunteers. The purpose of the present study was to assess the effect of pretreatment with terfenadine, a nonsedating antihistamine on the pathophysiologic consequences of intranasal histamine challenge. Fifteen subjects with allergic rhinitis were challenged intranasally with saline and increasing histamine doses (0.01, 0.1, 0.5, 1.0, 5.0, and 10.0 mg) before pretreatment (baseline) and after 1 week of pretreatment with terfenadine, 60 mg b.i.d., terfenadine, 120 mg b.i.d., and placebo. Nasal conductance as measured by posterior rhinomanometry showed a dose-dependent, monotonic decrease following sequential administration of the histamine solutions, but there were no apparent differences in the average responses among the four challenge sessions. The frequency of ETO after histamine challenge was decreased by pretreatment with both doses of terfenadine, although this was not significant. Histamine-induced sneezing and rhinorrhea, but not congestion, were significantly reduced by terfenadine pretreatment. There was no evidence of extension of the histamine effects to the lower airway. The results of the present study suggest that terfenadine, a nonsedating antihistamine, had a favorable effect on sneezing and rhinorrhea after provocative intranasal histamine challenge, but did not significantly attenuate the subjective or objective nasal and ET obstructive responses.

A double-blind, placebo-controlled clinical trial of the effect of chlorpheniramine on the response of the nasal airway, middle ear and eustachian tube to provocative rhinovirus challenge.

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Doyle, W J; McBride, T P; Skoner, D P; Maddern, B R; Gwaltney, J M; Uhrin, M

1988-03-01

This paper presents the results of a randomized, double-blind, placebo-controlled study of the efficacy of chlorpheniramine in relieving the symptoms and attenuating the pathophysiologic correlates of a rhinovirus "common cold." Forty healthy, adult, nonatopic subjects were randomly assigned to one of two treatment groups: active drug and placebo. On study Day 0, all subjects were challenged intranasally with rhinovirus type 39 (dose = 100 TCID50). Subjects were cloistered from Day 2 to Day 7, at which time they were treated with either chlorpheniramine or placebo. From 3 days before challenge to study Day 19, subjects had nasal patency assessed by rhinomanometry, eustachian tube function assessed by the 9-step test and sonotubometry, middle ear pressure assessed by tympanometry and nasal clearance assessed by the dyed-saccharin technique. Symptom diaries were maintained throughout the period of follow-up. During cloister, symptoms also were scored by interview, nasal secretions were quantified and nasal washings were performed for viral culture. Results showed that 19 (95%) subjects in the active-treatment group and 18 (90%) subjects in the placebo-treatment group shed virus. Symptomatic colds were observed in 63% of the active-treated and 83% of the placebo-treated subjects. Symptoms increased on Day 1 and peaked at Days 4 to 5. Detrimental changes in other measured functions consistent with those previously reported were observed. During the period of treatment, significant differences in the average symptom scores favoring the active-treatment group were observed for sneezing. Also, weight of expelled secretions was greater and mucociliary clearance rate less on some cloister days for the placebo-treated group. No significant differences between treatment groups in the objective measures of nasal congestion or the response of the middle ear and eustachian tube were documented.

[The assessment of the clinical effectiveness of fenspiride for the treatment of acute obstruction of the Eustachian tube].

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Fedin, A V

2015-01-01

The objective of the present study was to estimate the clinical effectiveness of fenspiride used to correct the obstruction of the Eustachian tube in 80 patients presenting with acute tubootitis and exudative otitis media. The algorithm of the examination included the evaluation of the severity of subjective clinical symptoms based on the relevant analog-visual scale, results of tonal audiometry, and tympanometry. The control group was comprised of 34 patients treated with antibacterial preparations, topical decongestants, and transtubal administration of glucocorticoids. The study group included 46 patients who received fenspiride at a dose of 80 mg thrice daily in addition to the above pharmacotherapy. The severity of clinical symptoms in the patients treated with fenspiride decreased faster than in the control subjects. The frequency analysis of dynamics of the air-bone gaps on the audiometric curves revealed the significantly more intensive recovery of the hearing function in the patients treated by basal pharmacotherapy in the combination with fenspiride. Type A tympanograms predominated on day 7 after the onset of the conservative treatment with the use of fenspiride whereas type C tympanograms continued to predominate in the patients of the control group. It is concluded that the introduction of fenspiride into combined therapy of acute tubootitis and exudative otitis media promotes the normalization of the ventilation and drainage functions and relieves the severity of subjective clinical symptoms.

Do the angle and length of the eustachian tube influence the development of chronic otitis media?

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Dinç, Aykut Erdem; Damar, Murat; Uğur, Mehmet Birol; Öz, Ibrahim Ilker; Eliçora, Sultan Şevik; Bişkin, Sultan; Tutar, Hakan

2015-09-01

To compare the eustachian tube (ET) angle (ETa) and length (ETl) of ears with and without chronic otitis media (COM), and to determine the relationship between ET anatomy and the development of COM. A retrospective case-control study. The study group comprised 125 patients (age range, 8-79 years; 64 males and 61 females) with 124 normal ears and 126 diseased ears, including ears with chronic suppurative otitis media (CSOM) with central perforation, intratympanic tympanosclerosis (ITTS), cholesteatoma, and a tympanic membrane with retraction pockets (TMRP). ET angle and length were measured using computed tomography employing the multiplanar reconstruction technique. The ETa was significantly more horizontal in diseased versus normal ears of all study groups (P = .030), and there was no group difference in ETl (P = .160). ETl was shorter in CSOM versus ITTS ears and normal ears (P = .007 and P = .003, respectively) and in cholesteatoma versus TMRP ears (P = .014). In the unilateral COM group, there were no significant differences in the ETa or ETl of diseased versus contralateral normal ears (P = .155 and P = .710, respectively). The ETa was significantly more horizontal in childhood-onset diseased versus normal ears (P = .027), and there was no group difference in ETl (P = .732). The ETa (P = .002) and ETl (P < .001) were significantly greater in males than females. A more horizontal ETa and shorter ETl could be contributory (though not significantly) etiological factors in the development of COM. 3b. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Analyses of the eustachian tube and its surrounding tissues with cross sectional images by high-resolution computed tomography (HR-CT)

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Yoshida, Haruo; Kobayashi, Toshimitsu; Takasaki, Kenji; Kanda, Yukihiko; Nakao, Yoshiaki; Morikawa, Minoru; Ishimaru, Hideki; Hayashi, Kuniaki

2000-01-01

We attempted to image the eustachian tube (ET) and its surrounding tissues by high-resolution computed tomography (HR-CT). Twenty-two normal subjects (44 ears) without middle ear problems were studied, and a patient with severe patulous ET was also studied as an abnormal case. In our device of multiplanar reconstruction technique, we were able to obtain the clear reconstructed images of the ET lumen as well as of its surrounding tissues (bone, ET cartilage, tensor veli palatini muscle, levator veli palatini muscle, Ostmann's fat tissue, tensor tympani muscle, internal carotid artery) at any desired portion, either parallel or perpendicular to the long axis of the ET. However, the exact borders between the ET cartilage and the muscles, Ostmann's fat tissue and the tubal gland were not clearly identified. In the severe case of patulous ET, the ET lumen was widely opened at each cross-sectional image from the pharyngeal orifice to the tympanic orifice, in contrast with its being closed at the cartilaginous portion in the normal cases. In addition, the fat tissue and glands around the ET lumen were not clearly identified in this case. We suggest that this method will lead to better understanding of the ET-related diseases such as patulous ET. (author)

Analyses of the eustachian tube and its surrounding tissues with cross sectional images by high-resolution computed tomography (HR-CT)

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Yoshida, Haruo; Kobayashi, Toshimitsu; Takasaki, Kenji; Kanda, Yukihiko; Nakao, Yoshiaki; Morikawa, Minoru; Ishimaru, Hideki; Hayashi, Kuniaki [Nagasaki Univ. (Japan). School of Medicine

2000-07-01

We attempted to image the eustachian tube (ET) and its surrounding tissues by high-resolution computed tomography (HR-CT). Twenty-two normal subjects (44 ears) without middle ear problems were studied, and a patient with severe patulous ET was also studied as an abnormal case. In our device of multiplanar reconstruction technique, we were able to obtain the clear reconstructed images of the ET lumen as well as of its surrounding tissues (bone, ET cartilage, tensor veli palatini muscle, levator veli palatini muscle, Ostmann's fat tissue, tensor tympani muscle, internal carotid artery) at any desired portion, either parallel or perpendicular to the long axis of the ET. However, the exact borders between the ET cartilage and the muscles, Ostmann's fat tissue and the tubal gland were not clearly identified. In the severe case of patulous ET, the ET lumen was widely opened at each cross-sectional image from the pharyngeal orifice to the tympanic orifice, in contrast with its being closed at the cartilaginous portion in the normal cases. In addition, the fat tissue and glands around the ET lumen were not clearly identified in this case. We suggest that this method will lead to better understanding of the ET-related diseases such as patulous ET. (author)

[Long-term follow-up after tympanostomy tube insertion in children with serous otitis media].

Science.gov (United States)

Fekete-Szabó, Gabriella; Kiss, Fekete; Rovó, László

2015-11-15

The authors report about the efficacy of inserted tympanostomy tube in children with serous otitis media. The aim of the authors was to assess the status of eardrum, the function of Eustachian tube and hearing level 10 years after the use of tympanostomy tube. Patients filled out a questionnaire and microscopic examination of tympanic membrane, tympanometry, Eustachian tube function examination, and audiometry tests were performed. In the period of 2003-2004, ventilation tube insertion was performed in 711 patients in the ENT Department of Pediatric Health Center of University of Szeged. In 349 patients adenotomy and tympanostomy tube insertion, in 18 cases tonsillectomy and grommet insertion and in 344 patients only typmanostomy tube insertion were performed. Due to objective difficulties (address change, no phone number) 453 patients were asked for control test and 312 persons accepted the invitation. Normal hearing level was found in 84.6% of patients and normal tympanometry result occurred in 82%. Tympanic ventilation disorder, perforation of tympanic membrane, sensorineural hearing loss and sensorineural hearing loss due to noise exposure were diagnosed. Application of tympanostomy tube is effective in the treatment of serous otitis media resulting from ventilation disorder. The authors draw attention to the importance of tympanometry examination to prevent the adhesive processes and cholesteatoma in chronic ventilation disorder of the middle ear.

Is there a difference between active opening of the Eustachian tube in a hypobaric surrounding compared to a hyperbaric surrounding?

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Mikolajczak, Stefanie; Meyer, Moritz Friedo; Felsch, Moritz; Jumah, Masen Dirk; Hüttenbrink, Karl-Bernd; Grosheva, Maria; Luers, Jan-Christoffer; Beutner, Dirk

2015-01-01

The Eustachian tube (ET) is the key to pressure equalization between the middle ear and ambient pressure. To date, little is known about differences of the opening mechanisms under hyper- or hypobaric conditions. Aim of this study was to compare standard ET opening parameters during standardized hypo- and hyperbaric exposures. Thirty healthy participants were exposed to a standardized profile of decompression and compression (SPDC) in a hypo-/hyperbaric pressure chamber. Impedance, expressed as tympanic membrane compliance, was recorded at intervals during the excursions from 1 atmosphere absolute (atm abs) to 0.8 and 1.2 atm abs respectively. Parameters for tubal opening were obtained during SPDC: ET opening pressure (ETOP), ET opening duration (ETOD) and ET opening frequency (ETOF), hypobaric (Phase 1) and hyperbaric (Phase 2) data were compared. Mean value for Valsalva maneuver ETOP was 40.10 ± 19.02 mbar in Phase 2 vs. 42.82 ± 21.75 mbar in Phase 1. For ETOD it was 2.80 ± 2.09 seconds in Phase 2 vs. 2.51 ± 1.90 seconds in Phase 1. For swallowing, mean value for ETOP was 33.47 ± 14.50 mbar in Phase 2 vs. 28.44 ± 14.04 in Phase 1. ETOD was 0.82 ± 0.60 seconds in Phase 2 vs. 0.76 ± 0.55 seconds in Phase 1. There was no statistical significance for ETOP, ETOD and ETOF between the two phases. No statistical significant difference was evident for active pressure equalization (Valsalva and swallowing) between a hyperbaric setting (dive) and a hypobaric setting (flight) in healthy subjects.

Large Eustachian valve: An incidental finding yet perplexing

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Anju Sarupria

2014-01-01

Full Text Available Eustachian valve (EV, a remnant of the right valve of sinus venosus in the right atrium can be puzzling. Often it is confused with Chiari network or atrial adhesions and is reported with unusual complications. We report a case of large EV impeding cannulation of inferior vena cava (IVC during aortic valve replacement. Transesophageal echocardiography diagnosed the presence of large EV and warned of the difficulty with IVC cannulation and helped preparedness for an alternative plan during surgery.

Retrospective results of radiation therapy of the Eustachian tube in chronic otitis media; Retrospektive Ergebnisse der perkutanen Strahlentherapie der Tuba Eustachii bei chronischer Otitis media

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Schultze, J.; Reinke, C.; Kimmig, B. [Klinik fuer Strahlentherapie (Radioonkologie), Universitaetsklinikum Kiel (Germany); Frese, K.A. [Klinik fuer Hals-, Nasen- und Ohrenheilkunde, Kopf- und Halschirurgie, Universitaetsklinikum Kiel (Germany)

2003-01-01

Background: The treatment results of symptomatic radiation therapy of the Eustachian tube in chronic otitis media had to be evaluated retrospectively. Patients and Methods: Between 1980 and 1997, 66 patients were referred for therapy. The median age was 58 years. In the clinical presentation, all the patients had a hearing impairment, 35 patients complained of pain, 21 had otorrhea. In their history, 20 patients indicated chronic recurrent infections. The complaints lasted for 4.7 years in the median, primary conservative (adstringentia, antibiotics) and surgical treatment (paracentesis, tympanic tubule, tympanoplastic) did not lead to lasting cure. In 40 of 66 patients, finally radiation therapy was done of both Eustachian tubes. With opposed fields and cobalt-60 photons a total dose of 6 Gy at single doses of 1 Gy, three times a week, was applied. Under the causes for exclusion of radiation therapy were non-acceptance of the patients (nine), prior radiation therapies (six) or spontaneous improvement after initial presentation in our department. The treatment results were evaluated by interviews of the patients and regular otorhinolaryngological examinations. Results: There were no side effects noticed. 28 of 40 (70%) patients reported a significant improvement that could be verified by objective otorhinolaryngological examinations. In the group of 26 nonirradiated patients, 22 could be interviewed indicating in 16 cases (72%) that the complaints were unchanged and chronic otitis media was lasting. In a subgroup analysis concerning the duration of otitis media radiation therapy proved more effective in an acute and subacute stadium of disease of up to 5 years duration, while the patients resistant to radiation therapy were entirely in a chronic stage of disease exceeding 5 years duration. (orig.) [German] Hintergrund: Die Behandlungsergebnisse der symptomatischen Radiotherapie bei chronischer Otitis media sollten retrospektiv evaluiert werden. Patienten und

Magnetic resonance imaging of nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Naito, Yasushi; Tamaki, Susumu; Kurata, Kyosuke; Honjo, Iwao; Nishimura, Kazumasa; Nakano, Yoshihisa

1987-01-01

Magnetic resonance imaging (MRI) of the nasopharynx, the eustachian tube and the middle ear was performed in nine patients with nasopharyngeal carcinoma. MRI revealed the extent of the tumor more clearly than CT (computed tomography) when the tumor was situated in the parapharyngeal space. But when the tumor extended superficially in the nasopharyngeal mucosa, its margin could not be identified clearly by either MRI or CT because of hypervascularity and long T1 and T2 of the nasopharyngeal mucosa. Seven of the nine patients had unilateral otitis media with effusion. Their eustachian tube ventilation function was evaluated by an inflation-deflation technique. Failure of active equalization of negative pressure applied to the middle ear was found to be a characteristic disorder of their eustachian tube ventilation function. This dysfunction seemed to be correlated with the lateral dislocation of the eustachian tube cartilage caused by the tumor. (author)

Magnetic resonance imaging of cleft palate

Energy Technology Data Exchange (ETDEWEB)

Naito, Yasushi; Tasaka, Yasuyuki; Honjo, Iwao; Nishimura, Kazumasa; Nakano, Yoshihisa

1987-03-01

Magnetic resonance imaging (MRI) of the nasopharynx and the eustachian tube was performed in five patients with cleft palate and compared with the results of those without this anomaly. Various degrees of deformity of the eustachian tube cartilage were found in cleft palate patients. The levator veli palatini muscles were situated more laterally in cleft palate patients than in normal subjects. Also, changes in the position of these muscles after palatoplasty were clearly depicted by MRI. Besides several autopsy reports, this is the first demonstration of the characteristic anomaly around the eustachian tube by a non-invasive method.

Eustachian Tube Dysfunction

Science.gov (United States)

... Kids and Teens Pregnancy and Childbirth Women Men Seniors Your Health Resources Healthcare Management End-of-Life Issues Insurance & Bills Self Care Working With Your Doctor Drugs, Procedures & Devices Over-the- ...

The role of the tensor veli palatini muscle in the development of cleft palate-associated middle ear problems.

Science.gov (United States)

Heidsieck, David S P; Smarius, Bram J A; Oomen, Karin P Q; Breugem, Corstiaan C

2016-09-01

Otitis media with effusion is common in infants with an unrepaired cleft palate. Although its prevalence is reduced after cleft surgery, many children continue to suffer from middle ear problems during childhood. While the tensor veli palatini muscle is thought to be involved in middle ear ventilation, evidence about its exact anatomy, function, and role in cleft palate surgery is limited. This study aimed to perform a thorough review of the literature on (1) the role of the tensor veli palatini muscle in the Eustachian tube opening and middle ear ventilation, (2) anatomical anomalies in cleft palate infants related to middle ear disease, and (3) their implications for surgical techniques used in cleft palate repair. A literature search on the MEDLINE database was performed using a combination of the keywords "tensor veli palatini muscle," "Eustachian tube," "otitis media with effusion," and "cleft palate." Several studies confirm the important role of the tensor veli palatini muscle in the Eustachian tube opening mechanism. Maintaining the integrity of the tensor veli palatini muscle during cleft palate surgery seems to improve long-term otological outcome. However, anatomical variations in cleft palate children may alter the effect of the tensor veli palatini muscle on the Eustachian tube's dilatation mechanism. More research is warranted to clarify the role of the tensor veli palatini muscle in cleft palate-associated Eustachian tube dysfunction and development of middle ear problems. Optimized surgical management of cleft palate could potentially reduce associated middle ear problems.

When to use femoral vein injection for diagnosis of patent foramen ovale-Effect of a persistent eustachian valve on right atrial flow patterns during contrast transesophageal echocardiography.

Science.gov (United States)

Koh, Tat W

2017-05-01

Contrast echocardiography using agitated saline injected into the antecubital vein is the most common method used for the diagnosis of patent foramen ovale. We describe a case whereby the presence of a persistent eustachian valve and a "negative contrast sign" during contrast transesophageal echocardiography raised suspicion of a false-negative result. Femoral vein injection of contrast successfully demonstrated a patent foramen ovale. Femoral vein injection should be considered if this scenario is recognized because the eustachian valve directs blood preferentially from the inferior vena cava toward the interatrial septum and this route may prove to be more reliable. © 2017, Wiley Periodicals, Inc.

Ballondilatation af det eustakiske rør er ny behandling til kronisk otitis media

DEFF Research Database (Denmark)

Møller, Martin Nue; Wanscher, Jens; Larsen, Per Leganger

2014-01-01

Balloon dilation of Eustachian tube is a novel method for managing chronic ventilatory dysfunction in patients with chronic otitis media, as an alternative to classic grommet insertion. Although few retrospective studies have been conducted the method seems to be rapid, simple and safe with promi......Balloon dilation of Eustachian tube is a novel method for managing chronic ventilatory dysfunction in patients with chronic otitis media, as an alternative to classic grommet insertion. Although few retrospective studies have been conducted the method seems to be rapid, simple and safe...

Diagnosis of cholesteatoma by high resolution computed tomography

International Nuclear Information System (INIS)

Kakitsubata, Yousuke; Kakitsubata, Sachiko; Ogata, Noboru; Asada, Keiko; Watanabe, Katsushi; Tohno, Tetsuya; Makino, Kohji

1988-01-01

Three normal volunteers and 57 patients with cholesteatoma were examined by high resolution computed tomography. Serial sections were made through the temporal bone at the nasaly inclined position of 30 degree to the orbitomeatal line (semiaxial plane ; SAP). The findings of temporal bone structures in normal subjects were evaluated in SAP and axial plane (OM). Although the both planes showed good visualization, SAP showed both the eustachian tube and tympanic cavity in one slice. In cholesteatoma soft tissue masses in the tympanic cavity, mastoid air cells and Eustachian tube were demonstrated clearly by SAP. (author)

[The anatomical features of the middle ear exerting the influence on the formation of exudative otitis media in the breast-fed infants of different gestational age].

Science.gov (United States)

Matroskin, A G; Rakhmanova, I V; Dreval', A A; Kislyakov, A N; Vladimirov, A I

The objective of the present study was to elucidate the anatomical features of the structure of the middle ear and eustachian tube in the breast-fed infants of different gestational age that may be responsible for the formation of exudates (fluids). We have examined 150 temporal bones obtained from the children's cadavers that were allocated to three groups as follows: 50 temporal bones obtained at weeks 26-30 weeks of gestation (group 1), 44 bones 31-36 weeks of gestation (group 2), and 37-40 weeks of gestation (full-term babies, group 3),The analysis of the data obtained on an individual bases revealed either increase or decreases in the selected characteristics of the eustachian tube in comparison with the respective average values as well as the well apparent predominance of a single change or a combination of alteration of several parameters in one case in 26-30 weeks and 31-36 weeks groups. No significant changes were found in group 1. It is concluded that the presence of a single change or a combination of two or three abnormal changes in the parameters of the bone structures of the eustachian tube can affect the development of the secretory process in the middle ear especially in the children born after 36 weeks of pregnancy.

An approach to chronic otitis media with effusion – the pros and ...

African Journals Online (AJOL)

membrane without a middle-ear effusion is called acute myringitis, often mistaken ... Currently the insertion of ventilation tubes (VTs or grommets). (Fig.1) is the most common surgical procedure performed in children worldwide.2. Pathoph ysiology. The eustachian tube has three main functions, i.e. protection, clearance and ...

Aetiology and pathology of otitis media with effusion in adult life.

Science.gov (United States)

Mills, R; Hathorn, I

2016-05-01

To gather and analyse information concerning the aetiology and pathology of otitis media with effusion in adults. A review of the English language literature from 1970 to the present was conducted. The available evidence suggests that otitis media with effusion in adult life is best viewed as a syndrome with a number of causes, including: infiltration of the eustachian tube by nasopharyngeal carcinoma and other local malignancies; changes in the middle ear and eustachian tube induced by radiotherapy; and systemic disease. There is now a body of evidence specifically related to the aetiology and pathology of otitis media with effusion in adult life. However, further research is required to fill in the gaps in our knowledge and understanding of this condition.

Cleft Lip and Cleft Palate

Science.gov (United States)

... refers to a cleft in the lip only accounting for 20 percent of all clefts. What causes ... malformation of the upper airway can affect the function of the Eustachian tube and increase the possibility ...

Ear Infection (Middle Ear)

Science.gov (United States)

... secretions from the middle ear Swelling, inflammation and mucus in the eustachian tubes from an upper respiratory ... your baby for at least six months. Breast milk contains antibodies that may offer protection from ear ...

Vertebrate pressure-gradient receivers

DEFF Research Database (Denmark)

Christensen-Dalsgaard, Jakob

2011-01-01

The eardrums of all terrestrial vertebrates (tetrapods) are connected through Eustachian tubes or interaural canals. In some of the animals, these connections create pressure-gradient directionality, an enhanced directionality by interaction of sound arriving at both sides of the eardrum and stro......The eardrums of all terrestrial vertebrates (tetrapods) are connected through Eustachian tubes or interaural canals. In some of the animals, these connections create pressure-gradient directionality, an enhanced directionality by interaction of sound arriving at both sides of the eardrum....... Recent vertebrates form a continuum from perfect interaural transmission (0 dB in a certain frequency band) and pronounced eardrum directionality (30-40 dB) in the lizards, over somewhat attenuated transmission and limited directionality in birds and frogs, to the strongly attenuated interaural...

[Digitalization study of sonotubometry device].

Science.gov (United States)

Li, Yang; Chen, Shu; Xu, Li; Nong, Dongxiao; Tang, Anzhou; Zhang, Zhiwei

2014-06-01

Sonotubometry is wildly used in developed countries, offers a easy, versatile and objective way to assess the function of Eustachian tube. The objectives of this study are to develop a low-cost digitalized device. The digitalized sonotubometry device was made of a personal computer with sound input and output accessories. The PC sound card, connected to a signal amplifier, exported probe band noise, while feedback sound was collected by a microphone. All 36 volunteers (72 ears) were involved in the sonotubometry test with JK-04A and CHN-08, in the conditions of dry-swallowing and wet-swallowing. The data were statistically analyzed using SPSS 13.0. The basic electroacoustic performance of the CHN-08 was acceptable. CHN-08 (7 kHz) detection and JK-04A consistency of kappa index was 0.472; CHN-08 (8 kHz) and JK-04A consistency of kappa index was 0.487; CHN-08 (7 kHz) and CHN-08 (8 kHz) consistency of kappa index was 0.688.Under the JK-04A, CHN-08 (7 kHz) and CHN-08 (8 kHz) three setups, Eustachian tube opening frequency was significantly lower for wet-swallowing than dry-swallowing, P digitalized sonotubometry is successfully developed. Its electroacoustic performance proved acceptable by authority assessments. The detection rate of CHN-08 is in accordance with that of JK-04A moderately. The study revealed that Eustachian tube is opened more easily by dry-swallowing than by wet-swallowing.

Connectivity analysis of suggestive brain areas involved in middle ear pressure regulation in humans

DEFF Research Database (Denmark)

SA, Sami; Gaihede, Michael

2010-01-01

, MEP counter-regulation presented as Eustachian tube openings with steep and fast pressure changes toward 0 Pa, whereas in others, gradual and slow pressure changes presented related to the mastoid; these changes sometimes crossed 0 Pa into opposite pressures. In many cases, combinations...... to continuous regulation of smaller pressures, whereas the tube was related to intermittent regulation of higher pressures....

Middle ear infection (otitis media) (image)

Science.gov (United States)

Otitis media is an inflammation or infection of the middle ear. Acute otitis media (acute ear infection) occurs when there is ... which causes production of fluid or pus. Chronic otitis media occurs when the eustachian tube becomes blocked ...

An audit of paediatric nasal foreign bodies in Ilorin, Nigeria

African Journals Online (AJOL)

methods of foreign body removal, employed by both otolaryngologists and ... made out of paper clips or hair pins have been described,16 and Hanson and .... Removal is best accomplished with a wax hook, eustachian tube catheter or cupped ...

Cancer incidence after nasopharyngeal radium irradiation

NARCIS (Netherlands)

Ronckers, Cécile M.; van Leeuwen, Flora E.; Hayes, Richard B.; Verduijn, Pieter G.; Stovall, Marilyn; Land, Charles E.

2002-01-01

From 1940 until 1970, nasopharyngeal radium irradiation was used to treat children and military personnel suffering from Eustachian tube failure attributable to local lymphoid hyperplasia. We studied cancer incidence in a cohort of 4339 Dutch patients treated with nasopharyngeal radium irradiation,

Ballondilatation af det eustakiske rør er ny behandling til kronisk otitis media

DEFF Research Database (Denmark)

Møller, Martin Nue; Wanscher, Jens; Larsen, Per Leganger

2014-01-01

Balloon dilation of Eustachian tube is a novel method for managing chronic ventilatory dysfunction in patients with chronic otitis media, as an alternative to classic grommet insertion. Although few retrospective studies have been conducted the method seems to be rapid, simple and safe...

Passage of albumin from the middle ear to the inner ear in otitis media in the chinchilla

International Nuclear Information System (INIS)

Goldberg, B.; Goycoolea, M.V.; Schleivert, P.M.; Shea, D.; Schachern, P.; Paparella, M.M.; Carpenter, A.M.

1981-01-01

A study of the permeability of the middle ear-inner ear interface for macromolecules was carried out in chinchillas with open and obstructed eustachian tubes utilizing tritiated human serum albumin and immunoelectrophoresis. Tritiated albumin was placed in the round window niche area or normal animals and animals in which the eustachian tubes had been obstructed for 24 hours or 14 days. The tritiated albumin was allowed to remain in the middle ear cavity for 24 hours, Samples of middle ear effusion, perilymph, blood and cerebrospinal fluid were collected and measured for radioactivity. Radioactivity was demonstrated in the perilymph. Samples of middle ear effusions and perilymph were also studied by immunoelectrophoresis with goat antihuman albumin. Albumin placed in the round window niche of an experimental animal could be recovered unchanged in the perilymph. The results suggest a pathophysiologic explanation for the association of otitis media and sensorineural hearing loss or endolymphatic hydrops

Mechanisms in adverse reactions to food. The ear

DEFF Research Database (Denmark)

Høst, A

1995-01-01

Otitis media with effusion is rarely caused by allergy to food. Allergic inflammation in the nasal mucosa, mainly due to IgE-mediated reactions to foods, may cause eustachian tube dysfunction and subsequent otitis media with effusion. Inflammatory mediators from the nasal mucosa transported via...

Otitis media

NARCIS (Netherlands)

Rovers, MM; Schilder, AGM; Zielhuis, GA; Rosenfeld, RM

2004-01-01

Otitis media (OM) continues to be one of the most common childhood infections and is a major cause of morbidity in children. The pathogenesis of OM is multifactorial, involving the adaptive and native immune system, Eustachian-tube dysfunction, viral and bacterial load, and genetic and environmental

Prospective study on the dose distribution to the acoustic structures during postoperative 3D conformal radiotherapy for parotid tumors. Dosimetric and audiometric aspects

International Nuclear Information System (INIS)

Jereczek-Fossa, Barbara A.

2011-01-01

To analyze dose distribution in the hearing organ and to evaluate the dose effect on the hearing thresholds in patients treated with post-parotidectomy 3-dimensional conformal radiotherapy (3D-CRT). A total of 17 patients received post-parotidectomy 3D-CRT (median dose: 63 Gy). The audiometric evaluation comprised pure tone audiometry and tympanometry performed before radiotherapy (RT) and 3, 6, and 24 months after RT. The ear structures were delineated on planning computer tomography scans. Mean and maximum doses were calculated and dose-volume histograms were plotted. Before RT, the median baseline audiometric thresholds were normal. At 3 months post-RT, 3 patients were diagnosed as having middle ear underpressure and/or effusion that resolved completely by 6 months. During 2-year follow-up, none of the ears showed perceptive hearing loss at speech frequencies. The mean doses at ipsilateral external auditory canal, mastoids cells, tympanic case, Eustachian tube, semicircular canals, and cochlea were 44.8 Gy, 39.0 Gy, 30.9 Gy, 33.0 Gy, 19.6 Gy, and 19.2 Gy, respectively. The doses to the contralateral ear were negligible, except for the Eustachian tube (up to 28.2 Gy). Post-parotidectomy 3D-CRT is associated with relatively low doses to the ear and the surrounding structures. Post-RT audiometry did not show any permanent (neither conductive nor perceptive) hearing impairment. Only in 3 patients were there signs of transient unilateral dysfunction of the Eustachian tube observed during the first few months after RT. Longer follow-up and larger patient series are warranted to confirm these preliminary findings. (orig.)

A unique anomaly of the ear: Oculo-auriculo-vertebral spectrum or an isolated disruption?

NARCIS (Netherlands)

Theunissen, Eleonoor A. R.; Hoogslag, Isabella C. M.; van Spronsen, Erik; Oostra, Roelof J.; Ebbens, Fenna A.

2017-01-01

We present a rare case of a neonate with an isolated congenital condition of his right ear involving the outer ear, middle ear, eustachian tube, and the facial nerve, with an external opening into the skull that connects to the oropharynx. Taking this bizarre aspect of the exterior lesion and the

Will Parents Participate in and Comply with Programs and Regimens Using Xylitol for Preventing Acute Otitis Media in Their Children?

Science.gov (United States)

Danhauer, Jeffrey L.; Johnson, Carole E.; Baker, Jason A.; Ryu, Jung A.; Smith, Rachel A.; Umeda, Claire J.

2015-01-01

Purpose: Antiadhesive properties in xylitol, a natural sugar alcohol, can help prevent acute otitis media (AOM) in children by inhibiting harmful bacteria from colonizing and adhering to oral and nasopharyngeal areas and traveling to the Eustachian tube and middle ear. This study investigated parents' willingness to use and comply with a regimen…

Work type II first branchial cleft cyst: a rare anomaly with a classical ...

African Journals Online (AJOL)

such cases. The branchial apparatus starts to appear between the fourth and the fifth weeks of fetal develop- ment. The apparatus consists of five arches consisting of the mesoderm, four clefts that consist of the ectoderm and four pouches that consist of the endoderm. The first branchial pouch forms the Eustachian tube and ...

Late health effects of radiation for Eustachian tube dysfunction

International Nuclear Information System (INIS)

Verduijn, P.G.

1988-01-01

A non-concurrent cohort study is described in which the effects of the Crowe therapy were examined with regard to the health of a population of persons who were irradiated in their youth. 284 refs.; 16 figs.; 45 tabs

Gastrostomy Tube (G-Tube)

Science.gov (United States)

... any of these problems: a dislodged tube a blocked or clogged tube any signs of infection (including redness, swelling, or warmth at the tube site; discharge that's yellow, green, or foul-smelling; fever) excessive bleeding or drainage from the tube site severe abdominal pain lasting ...

Computed tomography of the nasopharynx and related spaces. Part I: anatomy

International Nuclear Information System (INIS)

Silver, A.J.; Mawad, M.E.; Hilal, S.K.; Sane, P.; Ganti, S.R.

1983-01-01

The normal computed tomographic anatomy of the nasopharynx and pterygopalatine and infratemporal fossae is analyzed. Particular attention is given to the distinction between deglutitional and masticatory muscles. The relations of the palatal muscles to the eustachian tube are described in detail. Those soft-tissue features that, when they deviate from normal, can provide early detection of nasopharyngeal lesions are emphasized

Unusual extension of the first branchial cleft anomaly.

Science.gov (United States)

Ada, Mehmet; Korkut, Nazim; Güvenç, M Güven; Acioğlu, Engin; Yilmaz, Süleyman; Cevikbaş, Uğur

2006-03-01

First branchial cleft is the only branchial structure that persists as the external ear canal, while all other clefts are resorbed. Incomplete obliteration and the degree of closure cause the varied types of first branchial cleft anomalies. They were classified based on the anatomical and histological features. We present an unusual type of first branchial cleft anomaly involving the external auditory canal, the middle ear and the nasopharynx through the eustachian tube.

Petrous internal carotid aneurysm causing epistaxis: Balloon embolization with preservation of the parent vessel

Energy Technology Data Exchange (ETDEWEB)

Willinsky, R.; Lasjaunias, P.; Pruvost, P.; Boucherat, M.

1987-11-01

A patient with severe, recurrent posterior epistaxis was shown at angiography to have an aneurysm of the petrous portion of the internal carotid artery (ICA). Since childhood, she had had pain related to eustachian tube blockage by the aneurysm. An endovascular balloon embolization of the aneurysm was successful with preservation of the parent artery. The treatment resulted in resolution of the symptoms. The report confirms the usefulness of an angiographic protocol in evaluating vascular problems.

21 CFR 868.5800 - Tracheostomy tube and tube cuff.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tracheostomy tube and tube cuff. 868.5800 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5800 Tracheostomy tube and tube cuff. (a) Identification. A tracheostomy tube and tube cuff is a device intended to be placed into a...

Tube plug

International Nuclear Information System (INIS)

Zafred, P. R.

1985-01-01

The tube plug comprises a one piece mechanical plug having one open end and one closed end which is capable of being inserted in a heat exchange tube and internally expanded into contact with the inside surface of the heat exchange tube for preventing flow of a coolant through the heat exchange tube. The tube plug also comprises a groove extending around the outside circumference thereof which has an elastomeric material disposed in the groove for enhancing the seal between the tube plug and the tube

Ultrasonic inspection of tube to tube plate welds

International Nuclear Information System (INIS)

Telford, D.W.; Peat, T.S.

1985-01-01

To monitor the deterioration of a weld between a tube and tube plate which has been repaired by a repair sleeve inside the tube and brazed at one end to the tube, ultrasound from a crystal at the end of a rod is launched, in the form of Lamb-type waves, into the tube through the braze and allowed to travel along the tube to the weld and be reflected back along the tube. The technique may also be used for the type of heat exchanger in which, during construction, the tubes are welded to the tube plate via external sleeves in which case the ultrasound is used in a similar manner to inspect the sleeve/tube plate weld. an electromagnetic transducer may be used to generate the ultrasound. The ultrasonic head comprising the crystal and an acoustic baffle is mounted on a Perspex (RTM) rod which may be rotated by a stepping motor. Echo signals from the region of deterioration may be isolated by use of a time gate in the receiver. The device primarily detects circumferentially orientated cracks, and may be used in heat exchangers in nuclear power plants. (author)

Heat Exchanger Tube to Tube Sheet Joints Corrosion Behavior

Directory of Open Access Journals (Sweden)

M. Iancu

2013-03-01

Full Text Available Paper presents the studies made by the authors above the tube to tube sheet fittings of heat exchanger with fixed covers from hydrofining oil reforming unit. Tube fittings are critical zones for heat exchangers failures. On a device made from material tube and tube sheet at real joints dimensions were establish axial compression force and traction force at which tube is extracted from expanded joint. Were used two shapes joints with two types of fittings surfaces, one with smooth hole of tube sheet and other in which on boring surface we made a groove. From extracted expanded tube zones were made samples for corrosion tests in order to establish the corrosion rate, corrosion potential and corrosion current in working mediums such as hydrofining oil and industrial water at different temperatures. The corrosion rate values and the temperature influence are important to evaluate joints durability and also the results obtained shows that the boring tube sheet shape with a groove on hole tube shape presents a better corrosion behavior then the shape with smooth hole tube sheet.

Tube spacer grid for a heat-exchanger tube bundle

International Nuclear Information System (INIS)

Scheidl, H.

1976-01-01

A tube spacer grid for a heat-exchanger tube bundle is formed by an annular grid frame having a groove formed in its inner surface in which the interspaced grid bars have their ends positioned and held in interspaced relationship by short sections of tubes passed through holes axially formed in the grid frame so that the tubes are positioned between the ends of the grid bars in the grooves. The tube sections may be cut from the same tubes used to form the tube bundle. 5 claims, 3 drawing figures

The Army Air Forces in World War II. Volume 7. Services Around the World

Science.gov (United States)

1983-01-01

imaginative recruitment campaign was initiated, which included press releases in professional journals and regular news media , personal solicitation...resulting from the blocked Eustachian tube, an inflammatory or suppurative otitis media develops. The acute process runs a course of a few days to a few...Bandel to Staff Directors, 2 3 Htst -3 pp. 37-71, 395-96. 63. 1bid.V pp-.372* 3999 477- - - Fed. 1944. ’ 71. “Wacs in the EuroDean Division. ATC

Petrous internal carotid aneurysm causing epistaxis: Balloon embolization with preservation of the parent vessel

International Nuclear Information System (INIS)

Willinsky, R.; Lasjaunias, P.; Pruvost, P.

1987-01-01

A patient with severe, recurrent posterior epistaxis was shown at angiography to have an aneurysm of the petrous portion of the internal carotid artery (ICA). Since childhood, she had had pain related to eustachian tube blockage by the aneurysm. An endovascular balloon embolization of the aneurysm was successful with preservation of the parent artery. The treatment resulted in resolution of the symptoms. The report confirms the usefulness of an angiographic protocol in evaluating vascular problems. (orig.)

Human evolutionary history: consequences for the pathogenesis of otitis media.

Science.gov (United States)

Bluestone, Charles D; Swarts, J Douglas

2010-12-01

The pathogenesis of otitis media is multifactorial, but the role of evolution on its development has not been addressed. We posit that the high prevalence of middle-ear disease is most likely restricted to humans, in contrast to other wild species, because the associated hearing loss would have reduced the fitness of affected individuals as a result of predation. We present here the possible consequences of two human adaptations that may have resulted in ubiquitous otitis media: the interaction of bipedalism and increased brain size, and the loss of facial prognathism resulting from speech or cooking. As a consequence of our adaptation for bipedalism, the female pelvic outlet is constricted, which, in the context of a rapidly enlarging brain, results in humans being born 12 months too soon. Significantly, immature eustachian tube structure and function, in conjunction with an immature immune system, helps to explain the high incidence of otitis media in the first year of life. But the persistence of middle-ear disease beyond this stage is not explained by "immaturity." The morphology of the palate changed with the adaptations that produced facial flattening, with concomitant effects on eustachian tube function. These changes resulted in relatively poor human physiologic tubal function in comparison to the nonhuman primate. Copyright © 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.

Tube holding system

International Nuclear Information System (INIS)

Cunningham, R.C.

1978-01-01

A tube holding rig is described for the lateral support of tubes arranged in tight parcels in a heat exchanger. This tube holding rig includes not less than two tube supporting assemblies, with a space between them, located crosswise with respect to the tubes, each supporting assembly comprising a first set of parallel components in contact with the tubes, whilst a second set of components is also in contact with the tubes. These two sets of parts together define apertures through which the tubes pass [fr

HF electronic tubes. Technologies, grid tubes and klystrons

International Nuclear Information System (INIS)

Lemoine, Th.

2009-01-01

This article gives an overview of the basic technologies of electronic tubes: cathodes, electronic optics, vacuum and high voltage. Then the grid tubes, klystrons and inductive output tubes (IOT) are introduced. Content: 1 - context and classification; 2 - electronic tube technologies: cathodes, electronic optics, magnetic confinement (linear tubes), periodic permanent magnet (PPM) focussing, collectors, depressed collectors; 3 - vacuum technologies: vacuum quality, surface effects and interaction with electrostatic and RF fields, secondary emission, multipactor effect, thermo-electronic emission; 4 - grid tubes: operation of a triode, tetrodes, dynamic operation and classes of use, 'common grid' and 'common cathode' operation, ranges of utilisation and limitations, operation of a tetrode on unadjusted load, lifetime of a tetrode, uses of grid tubes; 5 - klystrons: operation, impact of space charge, multi-cavity klystrons, interaction efficiency, extended interaction klystrons, relation between interaction efficiency, perveance and efficiency, ranges of utilization and power limitations, multi-beam klystrons and sheet beam klystrons, operation on unadjusted load, klystron band pass and lifetime, uses; 6 - IOT: principle of operation, ranges of utilisation and limitations, interaction efficiency and depressed collector IOT, IOT lifetime and uses. (J.S.)

Tube to tube excursive instability - sensitivities and transients

International Nuclear Information System (INIS)

Brown, M.; Layland, M.W.

1980-01-01

A simple basic analysis of excursive instability in a boiler tube shows how it depends upon operating conditions and physical properties. A detailed mathematical model of an AGR boiler is used to conduct a steady state parameter sensitivity survey. It is possible from this basis to anticipate the effects of changes in operating conditions and changes in design parameters upon tube to tube stability. Dynamic responses of tubes operating near the stability threshold are examined using a mathematical model. Simulated excursions are triggered by imparting small abrupt pressure changes on the boiler inlet pressure. The influences of the magnitude of the pressure change, waterside friction factor and gas side coupling between tubes are examined. (author)

Tube-support response to tube-denting evaluation. Volume 1. Final report

International Nuclear Information System (INIS)

Anderson, P.L.; Hall, J.F.; Shah, P.K.; Wills, R.L.

1983-05-01

The response of the tube supports is one of the important considerations of tube denting in a steam generator. Investigations have indicated that damaged tube supports have the potential to distort and damage tubes. This investigation considers the response to tube denting of the Combustion Engineering type tube supports. Drilled support plates and eggcrate tube supports are tested in a model steam generator in which tube denting is induced. The experimental data is used to verify and refine analytical predictor models developed using finite element techniques. It was found that analytical models underpredicted the deformations of the tube supports and appropriate modifications to enhance the predictive capability are identified. Non-destructive examination methods are evaluated for application to operating steam generators. It was found that the standard eddy current and profilometry techniques are acceptable methods for determining tube deformations, but these techniques are not adequate to assess tube support damage. Radiography is judged to be the best available means of determining the extent and progression of damage in tube supports

Condenser tube buckling within tube-tubesheet joints

International Nuclear Information System (INIS)

Willertz, L.E.; Kalnins, A.; Updike, D.P.

1991-01-01

The problem of the appearance of protrusions, or bumps, in the interior of roller-expanded tubes within a tubesheet is addressed. Such bumps have been observed in condensers of power plants. A brief history of the reported occurrences of the bumps is given. The hypothesis is advanced that the mechanics of the formation of the bumps is similar to a buckling problem that has 'bifurcation at infinity'. Following this hypothesis, a two-dimensional physical model is developed, and the application of this model to study a three-dimensional bump is proposed. It is proposed in this paper that an initial deviation from the circular shape of the tube required to produce a bump. It is shown that without such a deviation the tubes cannot buckle. An experiment with short tube segments has been performed that verifies some of the features of the observed condenser tube bumps. Exactly what force produced the initial deviation for the observed bumps is still unknown. Available evidence implicates the hydro-laser jet that is used in the cleaning of tubes and tubesheets. A scenario of how a bump could have been produced by the hydro-laser jet is proposed. (author)

Chest tube insertion

Science.gov (United States)

Chest drainage tube insertion; Insertion of tube into chest; Tube thoracostomy; Pericardial drain ... Be careful there are no kinks in your tube. The drainage system should always sit upright and be placed ...

Vibro-impact responses of a tube with tube--baffle interaction

International Nuclear Information System (INIS)

Shin, Y.S.; Sass, D.E.; Jendrzejczyk, J.A.

1978-01-01

The relatively small, inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the vibrational characteristics and the response of the tube. Numerical studies were made to predict the vibro-impact response of a tube with tube-baffle interaction. The finite element method has been employed with a non-linear elastic contact spring-dashpot to model the effect of the relative approach between the tube and the baffle plate. The coupled equations of motion are directly integrated with a proportional system damping represented by a linear combination of mass and stiffness. Lumped mass approach with explicit time integration scheme was found to be a suitable choice for tube-baffle impacting analysis. Fourier analyses indicate that the higher mode contributions to the tube response are significant for strong tube-baffle impacting. The contact damping forces are negligible compared with the contact spring forces. The numerical analysis results are in reasonably good agreement with those of the experiments

Panel 3

DEFF Research Database (Denmark)

Cayé-Thomasen, Per; Hermansson, Ann; Bakaletz, Lauren

2013-01-01

The pathogenesis of otitis media (OM) involves a number of factors related to the anatomy, pathology, and cell biology of the middle ear, the mastoid, the Eustachian tube, and the nasopharynx. Although some issues of pathogenesis are fairly well established, others are only marginally indicated b...... by current knowledge, and yet others remain undisclosed. The objective of this article is to provide a state-of-the-art review on recent scientific achievements in the pathogenesis of OM, as related to anatomy, pathology, and cell biology....

An 18FDG-PET/CT finding of a mediastinal abscess.

LENUS (Irish Health Repository)

Purcell, Yvonne Marie

2013-02-01

A 66-year-old man with left pyriform fossa squamous cell carcinoma (T2N0) was treated with chemoradiation. Nine months later, an emergency tracheostomy was performed for respiratory distress. Contrast-enhanced neck and thorax CT demonstrated a right pyriform mass. FDG-PET\\/CT showed linear increased uptake extending superiorly from the tracheostomy to the right Eustachian tube and inferiorly to the posterior mediastinum. Postmortem examination confirmed a 7 × 2.2 cm abscess extending from the right parapharyngeal, peritracheal, and prevertebral structures to the mediastinum.

Pressure tube reactor

International Nuclear Information System (INIS)

Susuki, Akira; Murata, Shigeto; Minato, Akihiko.

1993-01-01

In a pressure tube reactor, a reactor core is constituted by arranging more than two units of a minimum unit combination of a moderator sealing pipe containing a calandria tube having moderators there between and a calandria tube and moderators. The upper header and a lower header of the calandria tank containing moderators are communicated by way of the moderator sealing tube. Further, a gravitationally dropping mechanism is disposed for injecting neutron absorbing liquid to a calandria gas injection portion. A ratio between a moderator volume and a fuel volume is defined as a function of the inner diameter of the moderator sealing tube, the outer diameter of the calandria tube and the diameter of fuel pellets, and has no influence to intervals of a pressure tube lattice. The interval of the pressure tube lattice is enlarged without increasing the size of the pressure tube, to improve production efficiency of the reactor and set a coolant void coefficient more negative, thereby enabling to improve self controllability and safety. Further, the reactor scram can be conducted by injecting neutron absorbing liquid. (N.H.)

Vertical steam generator with slab-type tube-plate with even tube bundle washing

International Nuclear Information System (INIS)

Manek, O.; Masek, V.; Motejl, V.; Quitta, R.

1980-01-01

A shielding plate supporting the tubes attached to the tube plate of a vertical steam generator is mounted above the tube plate. Tube sleeves are designed with a dimensional tolerance relative to the heat transfer tubes and the sleeve end and the tube plate end. A separate space is thus formed above the tube plate in which circulation or feed water is introduced to flow between the branch and the heat transfer tube. This provides intensive washing of heat transfer tubes at a critical point and prevents deposit formation, thus excluding heat transfer tube failures. (J.B.)

Use of CATHENA to model calandria-tube/moderator heat transfer after pressure-tube/calandria-tube ballooning contact

International Nuclear Information System (INIS)

Fan, H.Z.; Bilanovic, Z.; Nitheanandan, T.

2004-01-01

A study was performed to assess the effect of the calandria-tube/moderator heat transfer after pressure-tube/calandria tube ballooning contact using CATHENA. Results of this study indicated that the analytical tool, CATHENA, can be applied for pool boiling heat transfer on the external surface of a large diameter tube, such as the calandria tube used in CANDU reactors. The methodology in such CANDU-generic study can be used to simulate the tube surface with multiple boiling regimes and to assess the benefits of closely coupling thermalhydraulics modelling and fuel/fuel channel behaviour modelling. CATHENA (Canadian Algorithm for THErmalhydraulic Network Analysis) is a one-dimensional, two-fluid thermalhydraulic simulation code designed by AECL to analyse two-phase flow and heat transfer in piping networks. The detailed heat transfer package in CATHENA allows a connection to be established from the multiple solid surfaces of tubes to the surrounding large amount of moderator water, which acts as a heat sink during a postulated loss of coolant event. The generalized heat transfer package within CATHENA allows the tube walls to be divided into several layers in the radial direction and several sectors in the circumferential direction, to account for heat transfer conditions in these two directions. The CATHENA code with the generalized heat transfer package is capable of capturing key pool-boiling phenomena such as nucleate, transition and film boiling heat transfer as well as an ability to model the rewet phenomenon to some extent. A CATHENA input model was generated and used in simulations of selected contact boiling experiment test cases. The transient wall temperatures have been calculated in different portions of the calandria tube. By using this model an adequate agreement was achieved between CATHENA calculation and experimental measurement The CATHENA code enables one to investigate the transient and local thermal-mechanical behaviour of the calandria tube

Improvement of pump tubes for gas guns and shock tube drivers

Science.gov (United States)

Bogdanoff, D. W.

1990-01-01

In a pump tube, a gas is mechanically compressed, producing very high pressures and sound speeds. The intensely heated gas produced in such a tube can be used to drive light gas guns and shock tubes. Three concepts are presented that have the potential to allow substantial reductions in the size and mass of the pump tube to be achieved. The first concept involves the use of one or more diaphragms in the pump tube, thus replacing a single compression process by multiple, successive compressions. The second concept involves a radical reduction in the length-to-diameter ratio of the pump tube and the pump tube piston. The third concept involves shock heating of the working gas by high explosives in a cyclindrical geometry reusable device. Preliminary design analyses are performed on all three concepts and they appear to be quite feasible. Reductions in the length and mass of the pump tube by factors up to about 11 and about 7, respectively, are predicted, relative to a benchmark conventional pump tube.

Increased susceptibility to otitis media in a Splunc1-deficient mouse model

Science.gov (United States)

Bartlett, Jennifer A.; Meyerholz, David K.; Wohlford-Lenane, Christine L.; Naumann, Paul W.; Salzman, Nita H.; McCray, Paul B.

2015-01-01

ABSTRACT Otitis media (inflammation of the middle ear) is one of the most common diseases of early childhood. Susceptibility to otitis is influenced by a number of factors, including the actions of innate immune molecules secreted by the epithelia lining the nasopharynx, middle ear and Eustachian tube. The SPLUNC1 (short palate, lung, nasal epithelial clone 1) protein is a highly abundant secretory product of the mammalian nasal, oral and respiratory mucosa that is thought to play a multifunctional role in host defense. In this study we investigated Splunc1 expression in the ear of the mouse, and examined whether this protein contributes to overall host defense in the middle ear and/or Eustachian tube. We found that Splunc1 is highly expressed in both the surface epithelium and in submucosal glands in these regions in wild-type mice. In mice lacking Splunc1, we noted histologically an increased frequency of otitis media, characterized by the accumulation of leukocytes (neutrophils with scattered macrophages), proteinaceous fluid and mucus in the middle ear lumens. Furthermore, many of these mice had extensive remodeling of the middle ear wall, suggesting a chronic course of disease. From these observations, we conclude that loss of Splunc1 predisposes mice to the development of otitis media. The Splunc1−/− mouse model should help investigators to better understand both the biological role of Splunc1 as well as host defense mechanisms in the middle ear. PMID:25765466

Vibro-impact responses of a tube with tube--baffle interaction. [LMFBR

Energy Technology Data Exchange (ETDEWEB)

Shin, Y S; Sass, D E; Jendrzejczyk, J A

1978-01-01

The relatively small, inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the vibrational characteristics and the response of the tube. Numerical studies were made to predict the vibro-impact response of a tube with tube-baffle interaction. The finite element method has been employed with a non-linear elastic contact spring-dashpot to model the effect of the relative approach between the tube and the baffle plate. The coupled equations of motion are directly integrated with a proportional system damping represented by a linear combination of mass and stiffness. Lumped mass approach with explicit time integration scheme was found to be a suitable choice for tube-baffle impacting analysis. Fourier analyses indicate that the higher mode contributions to the tube response are significant for strong tube-baffle impacting. The contact damping forces are negligible compared with the contact spring forces. The numerical analysis results are in reasonably good agreement with those of the experiments.

Bender/Coiler for Tubing

Science.gov (United States)

Stoltzfus, J. M.

1983-01-01

Easy-to-use tool makes coils of tubing. Tubing to be bend clamped with stop post. Die positioned snugly against tubing. Operator turns handle to slide die along tubing, pushing tubing into spiral groove on mandrel.

Visual and quantitative anaysis of cisternography for the detection of cerebrospinal fluid leakage

Energy Technology Data Exchange (ETDEWEB)

Choi, Eun Kyoung; Oh, Jin Kyoung; Yoo, Ik Dong; Kim, Dong Hyun; Chung, Yong An [College of Medicine, Incheon St. Mary' s Hospital, The Catholic University of Korea, Incheon (Korea, Republic of); Park, Sonya Young Ju [Dept. of Radiology, College of Medicine, Seoul St. Mary' s Hospital, The Catholic University of Korea, Seoul (Korea, Republic of)

2017-06-15

We herein present a case of a 29-year-old man with clear rhinorrhea, which persisted for 8 years following a myringotomy. After cotton pledgets were placed in several different regions of the nasal cavity, cisternography using Tc-99m DTPA was performed to measure the radioactivity of each pledget. Cisternography showed subtle uptake in the nasal cavity. However, intense uptake was detected in the pledget placed in the right eustachian tube orifice, where the pledget:serum count ratio was 10.3:1. The patient underwent duroplasty and cranioplasty, and the rhinorrhea resolved.

Visual and Quantitative Analysis of Cisternography for the Detection of Cerebrospinal Fluid Leakage.

Science.gov (United States)

Choi, Eun Kyoung; Oh, Jin Kyoung; Park, Sonya Youngju; Yoo, Ikdong; Kim, Dong-Hyun; Chung, Yong-An

2017-06-01

We herein present a case of a 29-year-old man with clear rhinorrhea, which persisted for 8 years following a myringotomy. After cotton pledgets were placed in several different regions of the nasal cavity, cisternography using Tc-99m DTPA was performed to measure the radioactivity of each pledget. Cisternography showed subtle uptake in the nasal cavity. However, intense uptake was detected in the pledget placed in the right eustachian tube orifice, where the pledget:serum count ratio was 10.3:1. The patient underwent duroplasty and cranioplasty, and the rhinorrhea resolved.

Case report: Unilateral conduction hearing loss due to central venous occlusion.

Science.gov (United States)

Ribeiro, Phillip; Patel, Swetal; Qazi, Rizwan A

2016-05-07

Central venous stenosis is a well-known complication in patients with vascular access for hemodialysis. We report two cases involving patients on hemodialysis with arteriovenous fistulas who developed reversible unilateral conductive hearing loss secondary to critical stenosis of central veins draining the arteriovenous dialysis access. A proposed mechanism for the patients' reversible unilateral hearing loss is pterygoid venous plexus congestion leading to decreased Eustachian tube patency. Endovascular therapy was conducted to treat the stenosis and the hearing loss of both patients was returned to near normal after successful central venous angioplasty.

Determination of eustachius tube ventilation functioning among benign type chronic suppurative otitis media and non-otitis media subjects using sonotubometry

Science.gov (United States)

Ikhwan, M.; Hafil, A. F.; Bramanthyo, B.

2017-08-01

The Eustachian tube (ET) is responsible for the ventilation, protection, and cleaning of the middle ear. ET dysfunction plays an important role in the pathogenesis of otitis media cases, and thus the treatment and prognosis of these cases is extremely dependent on adequate ET function, which can ultimately affect the success rate of middle ear reconstruction practices. Data research on the ET’s ventilation function is needed to ensure the success of therapy and surgery treatments in the case of Chronic Suppurative Otitis Media (CSOM) patients. This study aims to investigate ET ventilation functioning in benign type CSOM and non-otitis media subjects and to develop another modality to measure ET ventilation functioning in patients with intact and perforated tympanic membranes. A comparative cross-sectional study of 36 benign type CSOM patients and 80 non-otitis media subjects will be conducted using sonotubometry and the rated parameter measurements of ET opening frequency, amplitude and ET opening duration. Malfunctioning ventilation of the ET is more common among benign type CSOM subjects (47%) than among non-otitis media subjects (18.75%). There is a significant difference (p = 0.002) between the ET ventilation functioning of benign type CSOM subjects and non-otitis media subjects—benign type CSOM subjects have rates of malfunctioning ET ventilation that are 3.88 times higher than those of non-otitis media subjects. Patients with benign type CSOM are more likely to experience malfunctioning ET ventilation than are non-otitis media subjects.

Steam generator tube extraction

International Nuclear Information System (INIS)

Delorme, H.

1985-05-01

To enable tube examination on steam generators in service, Framatome has now developed a process for removing sections of steam generator tubes. Tube sections can be removed without being damaged for treating the tube section expanded in the tube sheet

Feeding tube - infants

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/007235.htm Feeding tube - infants To use the sharing features on this page, please enable JavaScript. A feeding tube is a small, soft, plastic tube placed ...

Effect of tube-support interaction on the dynamic responses of heat exchanger tubes

International Nuclear Information System (INIS)

Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

1977-01-01

Operating heat exchangers have experienced tube damages due to excessive flow-induced vibration. The relatively small inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the tube vibrational characteristics. In attempting a theoretical analysis, questions arise as to the effects of tube-baffle impacting on dynamic responses. Experiments were performed to determine the effects of tube-baffle impacting in vertical/horizontal tube orientation, and in air/water medium on the vibrational characteristics (resonant frequencies, mode shapes, and damping) and displacement response amplitudes of a seven-span tube model. The tube and support conditions were prototypic, and overall length approximately one-third that of a straight tube segment of the steam generator designed for the CRBR. The test results were compared with the analytical results based on the multispan beam with ''knife-edge'' supports

Annular gap measurement between pressure tube and calandria tube by eddy current technique

International Nuclear Information System (INIS)

Bhole, V.M.; Rastogi, P.K.; Kulkarni, P.G.

1992-01-01

In pressurised heavy water reactor (PHWR) major distinguishing feature is that there are number of identical fuel channels in the reactor core. Each channel consists of pressure tube of Zr-2.5 Nb or zircaloy-2 through which high temperature, high pressure primary coolant is passing. The pressure tube contains fuel. Surrounding the pressure tube there is low pressure, cool heavy water (moderator). The moderator is thermally separated from coolant by the tube which is nominally concentric with pressure tube called calandria tube. There are four garter springs in the annular gap between pressure tube and calandria tube. During the life of the reactor there are number of factors by which the pressure tube sags, most important factors are irradiation creep, thermal creep, fuel load etc. Because of the sag of pressure tube it can touch the calandria tube resulting in formation of cold spot. This leads to hydrogen concentration at that spot by which the material at that place becomes brittle and can lead to catastrophic failure of pressure tube. There is no useful access for measurement of annular gap either through the gas annular space or from exterior of calandria tube. So the annular gap was measured from inside surface of pressure tube which is accessible. Eddy current technique was used for finding the gap. The paper describe the details of split coil design of bobbin probe, selection of operating point on normalised impedance diagram by choosing frequency. Experimental results on full scale mock up, and actual gap measurement in reactor channel, are also given. (author). 7 figs

Categorising YouTube

DEFF Research Database (Denmark)

Simonsen, Thomas Mosebo

2011-01-01

This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube......’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition...... and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within...

Pressure tube type reactors

International Nuclear Information System (INIS)

Komada, Masaoki.

1981-01-01

Purpose: To increase the safety of pressure tube type reactors by providing an additional ECCS system to an ordinary ECCS system and injecting heavy water in the reactor core tank into pressure tubes upon fractures of the tubes. Constitution: Upon fractures of pressure tubes, reduction of the pressure in the fractured tubes to the atmospheric pressure in confirmed and the electromagnetic valve is operated to completely isolate the pressure tubes from the fractured portion. Then, the heavy water in the reactor core tank flows into and spontaneously recycles through the pressure tubes to cool the fuels in the tube to prevent their meltdown. By additionally providing the separate ECCS system to the ordinary ECCS system, fuels can be cooled upon loss of coolant accidents to improve the safety of the reactors. (Moriyama, K.)

Tube-in-shell heat exchangers

International Nuclear Information System (INIS)

Richardson, J.

1976-01-01

Tube-in-shell heat exchangers normally comprise a bundle of parallel tubes within a shell container, with a fluid arranged to flow through the tubes in heat exchange with a second fluid flowing through the shell. The tubes are usually end supported by the tube plates that separate the two fluids, and in use the tube attachments to the tube plates and the tube plates can be subject to severe stress by thermal shock and frequent inspection and servicing are required. Where the heat exchangers are immersed in a coolant such as liquid Na such inspection is difficult. In the arrangement described a longitudinally extending central tube is provided incorporating axially spaced cylindrical tube plates to which the opposite ends of the tubes are attached. Within this tube there is a tubular baffle that slidably seals against the wall of the tube between the cylindrical tube plates to define two co-axial flow ducts. These ducts are interconnected at the closed end of the tube by the heat exchange tubes and the baffle comprises inner and outer spaced walls with the interspace containing Ar. The baffle is easily removable and can be withdrawn to enable insertion of equipment for inspecting the wall of the tube and tube attachments and to facilitate plugging of defective tubes. Cylindrical tube plates are believed to be superior for carrying pressure loads and resisting the effects of thermal shock. Some protection against thermal shock can be effected by arranging that the secondary heat exchange fluid is on the tube side, and by providing a thermal baffle to prevent direct impingement of hot primary fluid on to the cylindrical tube plates. The inner wall of the tubular baffle may have flexible expansible region. Some nuclear reactor constructions incorporating such an arrangement are described, including liquid metal reactors. (U.K.)

Heat exchanger tube tool

International Nuclear Information System (INIS)

Gugel, G.

1976-01-01

Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

Observation of "YouTube" Language Learning Videos ("YouTube" LLVS)

Science.gov (United States)

Alhamami, Munassir

2013-01-01

This paper navigates into the "YouTube" website as one of the most usable online tools to learn languages these days. The paper focuses on two issues in creating "YouTube" language learning videos: pedagogy and technology. After observing the existing "YouTube" LLVs, the study presents a novel rubric that is directed…

Helically coiled tube heat exchanger

International Nuclear Information System (INIS)

Harris, A.M.

1981-01-01

In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

Categorising YouTube

OpenAIRE

Simonsen, Thomas Mosebo

2011-01-01

This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a...

THE PRESENCE OF ADENOID VEGETATIONS AND NASAL SPEECH, AND HEARING LOSS IN RELATION TO SECRETORY OTITIS MEDIA

Directory of Open Access Journals (Sweden)

Gabriela KOPACHEVA

2004-12-01

Full Text Available This study presents the treatment of 68 children with secretory otitis media. Children underwent adenoid vegetations, nasal speech, conductive hearing loss, ventilation disturbance in Eustachian tube. In all children adenoidectomy was indicated.38 boys and 30 girls at the age of 3-17 were divided in two main groups: * 29 children without hypertrophic (enlarged adenoids, * 39 children with enlarged (hypertrophic adenoids.The surgical treatment included insertion of ventilation tubes and adenoidectomy where there where hypertrophic adenoids.Clinical material was analyzed according to hearing threshold, hearing level, middle ear condition estimated by pure tone audiometry and tympanometry before and after treatment. Data concerning both groups were compared.The results indicated that adenoidectomy combined with the ventilation tubes facilitates secretory otitis media heeling as well as decrease of hearing impairments. That enables prompt restoration of the hearing function as an important precondition for development of the language, social, emotional and academic development of children.

NEI You Tube Videos: Amblyopia

Medline Plus

Full Text Available ... YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: ...

Effect of Tube Pitch on Pool Boiling Heat Transfer of Vertical Tube Bundle

International Nuclear Information System (INIS)

Kang, Myeong Gie

2016-01-01

Summarizing the previous results it can be stated that heat transfer coefficients are highly dependent on the tube pitch and the heat flux of the relevant tube. The published results are mostly about the horizontal tubes. However, there are many heat exchangers consisting of vertical tubes like AP600. Therefore, the focus of the present study is an identification of the effects of a tube pitch as well as the heat flux of a relevant tube on the heat transfer of a tube bundle installed vertically. When the heat flux is increased many bubbles are generating due to the increase of the nucleation sites. The bubbles become coalescing with the nearby bubbles and generates big bunches of bubbles on the tube surface. This prevents the access of the liquid to the surface and deteriorates heat transfer. The bubble coalescence is competing with the mechanisms enhancing heat transfer. The pitch was varied from 28.5 mm to 95 mm and the heat flux of the nearby tube was changed from 0 to 90kW/m"2. The enhancement of the heat transfer is clearly observed when the heat flux of the nearby tube becomes larger and the heat flux of the upper tube is less than 40kW/m"2. The effect of the tube pitch on heat transfer is negligible as the value of DP/ is increased more than 4.

Optimizing Tube Precurvature to Enhance Elastic Stability of Concentric Tube Robots.

Science.gov (United States)

Ha, Junhyoung; Park, Frank C; Dupont, Pierre E

2017-02-01

Robotic instruments based on concentric tube technology are well suited to minimally invasive surgery since they are slender, can navigate inside small cavities and can reach around sensitive tissues by taking on shapes of varying curvature. Elastic instabilities can arise, however, when rotating one precurved tube inside another. In contrast to prior work that considered only tubes of piecewise constant precurvature, we allow precurvature to vary along the tube's arc length. Stability conditions for a planar tube pair are derived and used to formulate an optimal design problem. An analytic formulation of the optimal precurvature function is derived that achieves a desired tip orientation range while maximizing stability and respecting bending strain limits. This formulation also includes straight transmission segments at the proximal ends of the tubes. The result, confirmed by both numerical and physical experiment, enables designs with enhanced stability in comparison to designs of constant precurvature.

A Method to Establishing Tube Plugging Criterion for Heat Exchangers with Straight Tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyungnam [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

The difference of thermal expansion coefficients between the shell and tube materials causes the stress in axial direction of tube. Because of the axial stress due to thermal load, the straight tubes are used for heat exchangers operated in low temperature such as CCW (Component Cooling Water) heat exchangers and condensers. It is inevitable for the materials of the components to be degraded as the power plants become older. The degradation accompanies increasing maintenance cost as well as creating safety issues. The materials and wall thickness of heat exchanger tubes in nuclear power plants are selected to withstand system temperature, pressure, and corrosion. There are many codes and standards to be referred for calculating the minimum thickness of the heat exchanger tube in the designing stage. However, the codes and standards related to show the tube plugging criteria may not exist currently. In this paper, a method to establish the tube plugging criteria of BOP heat exchangers, which is based on the USNRC Regulatory Guide 1.121, is introduced and the tube plugging criteria for the TPCCW heat exchanger of Yonggwang NPP No. 1 and 2. A method to establish the tube plugging criteria of heat exchangers with straight tubes are introduced based on the USNRC Regulatory Guide 1.121. As an example, the tube plugging criterion for the CCW heat exchanger of a nuclear power plant is provided.

Automation in tube finishing bay

International Nuclear Information System (INIS)

Bhatnagar, Prateek; Satyadev, B.; Raghuraman, S.; Syama Sundara Rao, B.

1997-01-01

Automation concept in tube finishing bay, introduced after the final pass annealing of PHWR tubes resulted in integration of number of sub-systems in synchronisation with each other to produce final cut fuel tubes of specified length, tube finish etc. The tube finishing bay which was physically segregated into four distinct areas: 1. tube spreader and stacking area, 2. I.D. sand blasting area, 3. end conditioning, wad blowing, end capping and O.D. wet grinding area, 4. tube inspection, tube cutting and stacking area has been studied

CRL X-ray tube

International Nuclear Information System (INIS)

Kolchevsky, N.N.; Petrov, P.V.

2015-01-01

A novel types of X-ray tubes with refractive lenses are proposed. CRL-R X-ray tube consists of Compound Refractive Lens- CRL and Reflection X-ray tube. CRL acts as X-ray window. CRL-T X-ray consists of CRL and Transmission X-ray tube. CRL acts as target for electron beam. CRL refractive lens acts as filter, collimator, waveguide and focusing lens. Properties and construction of the CRL X-ray tube are discussed. (authors)

Pediatric cuffed endotracheal tubes

Directory of Open Access Journals (Sweden)

Neerja Bhardwaj

2013-01-01

Full Text Available Endotracheal intubation in children is usually performed utilizing uncuffed endotracheal tubes for conduct of anesthesia as well as for prolonged ventilation in critical care units. However, uncuffed tubes may require multiple changes to avoid excessive air leak, with subsequent environmental pollution making the technique uneconomical. In addition, monitoring of ventilatory parameters, exhaled volumes, and end-expiratory gases may be unreliable. All these problems can be avoided by use of cuffed endotracheal tubes. Besides, cuffed endotracheal tubes may be of advantage in special situations like laparoscopic surgery and in surgical conditions at risk of aspiration. Magnetic resonance imaging (MRI scans in children have found the narrowest portion of larynx at rima glottides. Cuffed endotracheal tubes, therefore, will form a complete seal with low cuff pressure of <15 cm H 2 O without any increase in airway complications. Till recently, the use of cuffed endotracheal tubes was limited by variations in the tube design marketed by different manufacturers. The introduction of a new cuffed endotracheal tube in the market with improved tracheal sealing characteristics may encourage increased safe use of these tubes in clinical practice. A literature search using search words "cuffed endotracheal tube" and "children" from 1980 to January 2012 in PUBMED was conducted. Based on the search, the advantages and potential benefits of cuffed ETT are reviewed in this article.

Prevalence of otitis media with effusion in children with allergic rhinitis, a cross sectional study.

Science.gov (United States)

Pau, Benjamin C; Ng, Daniel K

2016-05-01

Otitis media with effusion (OME) may be caused by various factors including Eustachian tube dysfunction, inflammatory response as well as atopy. Allergic rhinitis (AR), a common chronic disorder in children, is associated with swelling of the mucosa and can therefore result in Eustachian tube dysfunction. This study aims to compare the prevalence of OME in subjects with and without AR. Children aged 4-12 were recruited from the clinics at Kwong Wah Hospital, Hong Kong. Subjects recruited were interviewed and a questionnaire filled in regarding nasal obstruction, rhinorrhea, sneezing, itching of the nose and/or post nasal discharge (ARIR document). The children were then examined by a doctor using a pneumatic otoscopy and a portable tympanometer. Children found to have OME were offered a follow-up visit 3 months later. 12 out of 159 (7.5%) of the AR group were found to have OME compared with 3 out of 185 (1.6%) in the non-AR group, p=0.016. During the 2nd visit at 3 months, 85.7% of the AR subjects showed resolution of their OME. Our data showed a significant difference in the prevalence of OME between AR and non-AR subjects. Of the 185 non AR subjects (Control group), 3 was found to have OME, suggesting a point prevalence of OME of 1.6% in the community in Hong Kong. OME is more likely to occur in children with allergic rhinitis and it may be wiser to manage OME in these individuals differently. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Pressure tube type research reactor

International Nuclear Information System (INIS)

Ueda, Hiroshi.

1976-01-01

Object: To prevent excessive heat generation due to radiation of a pressure tube vessel. Structure: A pressure tube encasing therein a core comprises a dual construction comprising inner and outer tubes coaxially disposed. High speed cooling water is passed through the inner tube for cooling. In addition, in the outer periphery of said outer tube there is provided a forced cooling tube disposed coaxially thereto, into which cooling fluid, for example, such as moderator or reflector is forcibly passed. This forced cooling tube has its outer periphery surrounded by the vessel into which moderator or reflector is fed. By the provision of the dual construction of the pressure tube and the forced cooling tube, the vessel may be prevented from heat generation. (Ikeda, J.)

Streak tube development

International Nuclear Information System (INIS)

Hinrichs, C.K.; Estrella, R.M.

1979-01-01

A research program for the development of a high-speed, high-resolution streak image tube is described. This is one task in the development of a streak camera system with digital electronic readout, whose primary application is for diagnostics in underground nuclear testing. This program is concerned with the development of a high-resolution streak image tube compatible with x-ray input and electronic digital output. The tube must be capable of time resolution down to 100 psec and spatial resolution to provide greater than 1000 resolution elements across the cathode (much greater than presently available). Another objective is to develop the capability to make design changes in tube configurations to meet different experimental requirements. A demountable prototype streak tube was constructed, mounted on an optical bench, and placed in a vacuum system. Initial measurements of the tube resolution with an undeflected image show a resolution of 32 line pairs per millimeter over a cathode diameter of one inch, which is consistent with the predictions of the computer simulations. With the initial set of unoptmized deflection plates, the resolution pattern appeared to remain unchanged for static deflections of +- 1/2-inch, a total streak length of one inch, also consistent with the computer simulations. A passively mode-locked frequency-doubled dye laser is being developed as an ultraviolet pulsed light source to measure dynamic tube resolution during streaking. A sweep circuit to provide the deflection voltage in the prototype tube has been designed and constructed and provides a relatively linear ramp voltage with ramp durations adjustable between 10 and 1000 nsec

Technique employed to seal a tube leaking in a heat exchanger of the tube type by explosives with supporting means for the adjacent tubes

International Nuclear Information System (INIS)

Larson, G.C.

1978-01-01

This invention concerns the technique employed to seal a tube leaking in a heat exchanger of the tube and tube plate type by detonating metal plugs activated by an explosive and inserted in both ends of the tube. It refers in particular to an apparatus and process in which the deformation or distortion of the adjacent tubes and tube plate ties under the effect of the explosive forces is significantly reduced [fr

Steam generator tube performance

International Nuclear Information System (INIS)

Tatone, O.S.; Pathania, R.S.

1983-08-01

A review of the performance of steam generator tubes in 110 water-cooled nuclear power reactors showed that tubes were plugged at 46 (42 percent) of the reactors. The number of tubes removed from service increased from 1900 (0.14 percent) in 1980 to 4692 (0.30 percent) in 1981. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that used all-volatile treatment since start-up. At one reactor a large number of degraded tubes were repaired by sleeving which is expected to become an important method of tube repair in the future

Study on antioxidant experiment on forged steel tube sheet and tube hole for steam generator

International Nuclear Information System (INIS)

Zong Hai; Wang Detai; Ding Yang

2012-01-01

Antioxidant experiment on forged steel tube sheet and tube hole for steam generator was studied and the influence of different simulated heat treatments on the antioxidant performance of tube sheet and tube hole was made. The influence of different antioxidant methods on the size of tube hole was drawn. Furthermore, the change of size and weight of 18MnD5 forged steel tube sheet on the condition of different simulated heat treatments was also studied. The analytical results have proved reference information for the use of 18MnD5 material and for key processes of processing tube hole and wearing and expanding U-style tube. (authors)

Characterization of Friction Stir Welded Tubes by Means of Tube Bulge Test

International Nuclear Information System (INIS)

D'Urso, G.; Longo, M.; Giardini, C.

2011-01-01

Mechanical properties of friction stir welded joints are generally evaluated by means of conventional tensile test. This testing method might provide insufficient information because maximum strain obtained in tensile test before necking is small; moreover, the application of tensile test is limited when the joint path is not linear or even when the welds are executed on curved surfaces. Therefore, in some cases, it would be preferable to obtain the joints properties from other testing methods. Tube bulge test can be a valid solution for testing circumferential or longitudinal welds executed on tubular workpieces. The present work investigates the mechanical properties and the formability of friction stir welded tubes by means of tube bulge tests. The experimental campaign was performed on tubular specimens having a thickness of 3 mm and an external diameter of 40 mm, obtained starting from two semi-tubes longitudinally friction stir welded. The first step, regarding the fabrication of tubes, was performed combining a conventional forming process and friction stir welding. Sheets in Al-Mg-Si-Cu alloy AA6060 T6 were adopted for this purpose. Plates having a dimension of 225x60 mm were bent (with a bending axis parallel to the main dimension) in order to obtain semi-tubes. A particular care was devoted to the fabrication of forming devices (punch and die) in order to minimize the springback effects. Semi-tubes were then friction stir welded by means of a CNC machine tool. Some preliminary tests were carried out by varying the welding parameters, namely feed rate and rotational speed. A very simple tool having flat shoulder and cylindrical pin was used. The second step of the research was based on testing the welded tubes by means of tube bulge test. A specific equipment having axial actuators with a conical shape was adopted for this study. Some analyses were carried out on the tubes bulged up to a certain pressure level. In particular, the burst pressure and the

Heat exchanger with layers of helical tubes provided with improved tube supports

International Nuclear Information System (INIS)

Carnoy, M.; Mathieu, B.; Renaux, C.

1986-01-01

The present heat exchanger comprises coaxial layers of helically wound tubes; these tubes are supported by support plates, each comprising a row of perforations through which the tubes of a same layer pass. Truncated sleeves are in compression around the tubes within the perforations and mounted on the support plates. Pins fix the plates of different layers together against transverse movement but allowing radial movement. The present invention finds an application with nuclear reactor steam generators [fr

Pressure tube reactor

International Nuclear Information System (INIS)

Seki, Osamu; Kumasaka, Katsuyuki.

1988-01-01

Purpose: To remove the heat of reactor core using a great amount of moderators at the periphery of the reactor core as coolants. Constitution: Heat of a reactor core is removed by disposing a spontaneous recycling cooling device for cooling moderators in a moderator tank, without using additional power driven equipments. That is, a spontaneous recycling cooling device for cooling the moderators in the moderator tank is disposed. Further, the gap between the inner wall of a pressure tube guide pipe disposed through the vertical direction of a moderator tank and the outer wall of a pressure tube inserted through the guide pipe is made smaller than the rupture distortion caused by the thermal expansion upon overheating of the pressure tube and greater than the minimum gap required for heat shiels between the pressure tube and the pressure tube guide pipe during usual operation. In this way, even if such an accident as can not using a coolant cooling device comprising power driven equipment should occur in the pressure tube type reactor, the rise in the temperature of the reactor core can be retarded to obtain a margin with time. (Kamimura, M.)

An in-tube radar for detecting cracks in metal tubing

International Nuclear Information System (INIS)

Caffey, Thurlow W. H.; Nassersharif, Bahram; Garcia, Gabe V.; Smith, Phillip R.; Jedlicka, Russell P.; Hensel, Edward C.

2000-01-01

A major cause of failures in heat exchangers and steam generators in nuclear power plants is degradation of the tubes within them. The tube failure is often caused by the development of cracks that begin on the outer surface of the tube and propagate both inwards and laterally. A new technique will be described for detection of defects using a continuous-wave radar device within metal tubing. The technique is 100% volumetric, and may find smaller defects, find them more rapidly, and find them less expensively than present methods. Because this project was started only recently, there is no demonstrated performance to report so far. However, the basic engineering concepts will be presented together with a description of the milestone tasks and dates

Expansion lyre-shaped tube

International Nuclear Information System (INIS)

Andro, Jean.

1973-01-01

The invention relates the expansion lyre-shaped tube portions formed in dudgeoned tubular bundles between two bottom plates. An expansion lyre comprises at least two sets of tubes of unequal lengths coplanar and symmetrical with respect to the main tube axis, with connecting portions between the tubes forming said sets. The invention applies to apparatus such as heat exchangers, heaters, superheaters or breeders [fr

Steam generator tube failures

International Nuclear Information System (INIS)

MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

1996-04-01

A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

Prospects for stronger calandria tubes

International Nuclear Information System (INIS)

Ells, C.E.; Coleman, C.E.; Hosbons, R.R.; Ibrahim, E.F.; Doubt, G.L.

1990-12-01

The CANDU calandria tubes, made of seam welded and annealed Zircaloy-2, have given exemplary service in-reactor. Although not designed as a system pressure containment, calandria tubes may remain intact even in the face of pressure tube rupture. One such incident at Pickering Unit 2 demonstrated the economic advantage of such an outcome, and a case can be made for increasing the probability that other calandria tubes would perform in a similar fashion. Various methods of obtaining stronger calandria tubes are available, and reviewed here. When the tubes are internally pressurized, the weld is the weak section of the tube. Increasing the oxygen concentration in the starting sheet, and thickening the weld, are promising routes to a stronger tube

Fabrication of seamless calandria tubes

International Nuclear Information System (INIS)

Saibaba, N.; Phanibabu, C.; Bhaskara Rao, C.V.; Kalidas, R.; Ganguly, C.

2002-01-01

Full text: Calandria tube is a large diameter, thin walled zircaloy-4 tube and is an important structural component of PHWR type of reactors. These tubes are lifetime components and remain during the full life of the reactor. Calandria tubes are classified as extremely thin walled tubes with a diameter to wall thickness ratio of around 96. Such thin walled tubes are conventionally produced by seam welded route comprising of extrusion of slabs followed by a series of hot and rolling passes, shaping into O-shape and eventual welding. An alternative and superior method of fabricating the calandria tubes, the seamless route, has been developed, which involves hot extrusion of mother blanks followed by three successive cold pilger reductions. Eccentricity correction of the extruded blanks is carried out on a special purpose grinding equipment to bring the wall thickness variation within permissible limits. Predominant wall thickness reductions are given during cold pilgering to ensure high Q-factor values. The texture in the finished tubes could be closely, controlled with an average f r value of 0.65. Pilgering parameters and tube guiding system have been specially designed to facilities rolling of thin walled tubes. Seamless calandria tubes have distinct advantages over welded tubes. In addition to the absence of weld, they are dimensionally more stable, lighter in weight and possess uniform grains with superior grain size. The cycle time from billet to finished product is substantially reduced and the product is amenable to high level of quality assurance. The most significant feature of the seamless route is its material recovery over welded route. Residual stresses measured in the tubes indicate that these are negligible and uniform along the length of the tube. In view of their superior quality, the first charge of seamless calandria tubes will be rolled into the first 500 MWe Pressurised Heavy Water Reactor at Tarapur

Method for shaping polyethylene tubing

Science.gov (United States)

Kramer, R. C.

1981-01-01

Method forms polyethylene plastic tubing into configurations previously only possible with metal tubing. By using polyethylene in place of copper or stain less steel tubing inlow pressure systems, fabrication costs are significantly reduced. Polyethylene tubing can be used whenever low pressure tubing is needed in oil operations, aircraft and space applications, powerplants, and testing laboratories.

Spring/dimple instrument tube restraint

International Nuclear Information System (INIS)

DeMario, E.E.; Lawson, C.N.

1993-01-01

A nuclear fuel assembly for a pressurized water nuclear reactor has a spring and dimple structure formed in a non-radioactive insert tube placed in the top of a sensor receiving instrumentation tube thimble disposed in the fuel assembly and attached at a top nozzle, a bottom nozzle, and intermediate grids. The instrumentation tube thimble is open at the top, where the sensor or its connection extends through the cooling water for coupling to a sensor signal processor. The spring and dimple insert tube is mounted within the instrumentation tube thimble and extends downwardly adjacent the top. The springs and dimples restrain the sensor and its connections against lateral displacement causing impact with the instrumentation tube thimble due to the strong axial flow of cooling water. The instrumentation tube has a stainless steel outer sleeve and a zirconium alloy inner sleeve below the insert tube adjacent the top. The insert tube is relatively non-radioactivated inconel alloy. The opposed springs and dimples are formed on diametrically opposite inner walls of the insert tube, the springs being formed as spaced axial cuts in the insert tube, with a web of the insert tube between the cuts bowed radially inwardly for forming the spring, and the dimples being formed as radially inward protrusions opposed to the springs. 7 figures

Intercostal drainage tube or intracardiac drainage tube?

Science.gov (United States)

Anitha, N; Kamath, S Ganesh; Khymdeit, Edison; Prabhu, Manjunath

2016-01-01

Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

Pneumatic tube-transported blood samples in lithium heparinate gel separator tubes may be more susceptible to haemolysis than blood samples in serum tubes.

Science.gov (United States)

Böckel-Frohnhöfer, Nicole; Hübner, Ulrich; Hummel, Björn; Geisel, Jürgen

2014-10-01

Pneumatic tube systems are widely used in hospitals. Advantages are high speed and rapid availability of the samples. However, the transportation by pneumatic tube promotes haemolysis. Haemolysis interferes with many spectrophotometric assays and is a common problem in clinical laboratories. The haemolysis index (HI) as a semi-quantitative representation of the level of haemolysis was compared in unpaired tube-transported and hand-delivered routine lithium heparinate plasma samples (n = 1368 and n = 837, respectively). Additionally, the HI distribution was measured in lithium heparinate plasma samples with a HI above the threshold value of 20 and in paired serum samples after transportation by pneumatic tube system. HI values above 20 can interfere with the selected assays: Creatine kinase (CK), creatine kinase-MB (CK-MB) and alanine aminotransferase (ALT) activities. These parameters were determined to demonstrate how haemolysis affects the results. 17.5% of the tube-transported plasma samples and 2.6% of the hand-delivered plasma samples had a HI above 20. The median HI in pneumatic tube-transported lithium heparinate plasma was 85 and 33 in the paired serum samples. The median HI difference between paired plasma and serum was 46. Blood samples in lithium heparinate tubes may be substantially more susceptible to haemolysis by pneumatic tube transportation than serum tube samples. Although our results cannot be universally applied to laboratories with different pneumatic tube systems, it is recommended that each laboratory evaluate carefully the degree of haemolysis after the transportation by the own pneumatic tube system and in terms of the sample type.

A comparison of tape-tying versus a tube-holding device for securing endotracheal tubes in adults.

Science.gov (United States)

Murdoch, E; Holdgate, A

2007-10-01

During the transfer of intubated patients, endotracheal tube security is paramount. This study aims to compare two methods of securing an endotracheal tube in adults: tying with a cloth tape versus the Thomas Endotracheal Tube Holder (Laerdal). A manikin-based study was performed using paramedics and critical care doctors (consultants and senior trainees) as participants. Each participant was asked to secure an endotracheal tube that had been placed within the trachea of a manikin a total of six times, the first three times using tied cloth tape and the last three times using a Thomas Endotracheal Tube Holder. Following each 'fixation' and after the participant had left the room, the security of the tube was tested by applying a fixed force laterally and to the right by dropping a 1.25 kg weight a distance of 50 cm. The amount of movement of the tube with respect to the teeth was measured and recorded in millimetres. Two-hundred-and-seventy tube fixations (135 tied vs. 135 tube holder) were performed by 45 participants. The degree of tube movement was significantly higher when the tube was secured with a tie compared with when the tube holder was used (median movement 22 mm vs. 4 mm, P tube holder device minimised tube movement in a manikin model when compared with conventional tape tying. The use of this device when transporting intubated patients may reduce the risk of tube displacement though further clinical studies are warranted.

NEI You Tube Videos: Amblyopia

Medline Plus

Full Text Available ... search for current job openings visit HHS USAJobs Home >> NEI YouTube Videos >> NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

Double wall steam generator tubing

International Nuclear Information System (INIS)

Padden, T.R.; Uber, C.F.

1983-01-01

Double-walled steam generator tubing for the steam generators of a liquid metal cooled fast breeder reactor prevents sliding between the surfaces due to a mechanical interlock. Forces resulting from differential thermal expansion between the outer tube and the inner tube are insufficient in magnitude to cause shearing of base metal. The interlock is formed by jointly drawing the tubing, with the inside wall of the outer tube being already formed with grooves. The drawing causes the outer wall of the inner tube to form corrugations locking with the grooves. (author)

Learning from YouTube [Video Book

Science.gov (United States)

Juhasz, Alexandra

2011-01-01

YouTube is a mess. YouTube is for amateurs. YouTube dissolves the real. YouTube is host to inconceivable combos. YouTube is best for corporate-made community. YouTube is badly baked. These are a few of the things Media Studies professor Alexandra Juhasz (and her class) learned about YouTube when she set out to investigate what actually happens…

NEI You Tube Videos: Amblyopia

Medline Plus

Full Text Available ... search for current job openings visit HHS USAJobs Home » NEI YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

Heat transfer performance during in-tube condensation in horizontal smooth, micro-fin and herringbone tubes

OpenAIRE

2008-01-01

M.Ing. An experimental investigation was conducted into the heat transfer characteristics of horizontal smooth, micro-fin and herringbone tubes during in-tube condensation. The study focused on the heat transfer coefficients of refrigerants R-22, R-134a and R-407C inside the three tubes. The herringbone tube results were compared to the smooth and micro-fin tube results. The average increase in the heat transfer coefficient when compared to the smooth tube was found to be as high as 322% w...

Plugging criteria for steam generator tubes with axial cracks near tube support plates

International Nuclear Information System (INIS)

Mattar Neto, Miguel

2000-01-01

Stress corrosion cracking with intergranular attack occurs on the secondary side of steam generator (SG) tubes where impurities concentrate due to boiling under restricted flow conditions. In the most of cases, it can be called ODSCC (Outer Diameter Stress Corrosion Cracking). The typical locations are areas near support plates, in sludge piles and at top of tubesheet crevices. Though it can also occur on free spans under the relatively thin deposits that build up on the tube surfaces. ODSCC near tube plate supports have been the cause of plugging of many tubes. Thus, studies on SG tubes plugging criteria related to this degradation mechanism are presented in this paper. Th purpose is to avoid unnecessary tube plugging from either safety or reliability standpoint. Based on these studies some conclusions on the plugging criteria and on the difficulties to apply them are addressed. (author)

Intercostal drainage tube or intracardiac drainage tube?

Directory of Open Access Journals (Sweden)

N Anitha

2016-01-01

Full Text Available Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

Condensate subcooling near tube exit during horizontal in-tube condensation

International Nuclear Information System (INIS)

Hashizume, K.; Abe, N.; Ozeki, T.

1992-01-01

In-tube condensation is encountered in various applications for heat exchangers, such as domestic air-conditioning equipment, industrial air-cooled condensers, and moisture separator reheaters (MSRs) for nuclear power pants. Numerous research work has been conducted to predict the condensation heat transfer coefficient, and we have now enough information for thermal design of heat exchangers with horizontal in-tube condensation. Most of the research is analytical and/or experimental work in the annular or stratified flow regime, or experimental work on bulk condensation, i.e., from saturated vapor to complete condensation. On the other hand, there exist few data about the heat transfer phenomena in the very lower-quality region near the tube exit. The purpose of this paper is to clarify the condensation heat transfer phenomena near the tube exit experimentally and analytically, and to predict the degree of condensate subcooling

Microdischarges in DC accelerator tubes

International Nuclear Information System (INIS)

Eastham, D.A.; Thorn, R.

1978-07-01

Voltage tests on the Daresbury ceramic/titanium accelerator tube have shown that microdischarges play an important role in the conditioning process. It has been found that the voltage onset for microdischarges in a tube is dependent on the surface contamination of the electrodes and the tube geometry (in particular the tube length). This geometrical effect can be related to the trajectories of secondary ions emitted from the electrode surfaces. Sensitive diagnostic techniques have been developed to study the mass and energy distribution of ions emitted along the axis of the tube during these predischarges. The energy distribution of protons (and H - ions) can be related to the origins of the discharges in the tube. Detailed results are presented for a particular tube geometry. (author)

Expander for Thin-Wall Tubing

Science.gov (United States)

Pessin, R.

1983-01-01

Tool locally expands small-diameter tubes. Tube expander locally expands and deforms tube: Compressive lateral stress induced in elastomeric sleeve by squeezing axially between two metal tool parts. Adaptable to situations in which tube must have small bulge for mechanical support or flow control.

Categorising YouTube

Directory of Open Access Journals (Sweden)

Thomas Mosebo Simonsen

2011-09-01

Full Text Available This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC of YouTube. The article investigates the construction of navigationprocesses on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within the interacting relationship of new and old genres are discussed. It is argued that the utility of a conventional categorical system is primarily of analytical and theoretical interest rather than as a practical instrument.

Lunar Lava Tube Sensing

Science.gov (United States)

York, Cheryl Lynn; Walden, Bryce; Billings, Thomas L.; Reeder, P. Douglas

1992-01-01

Large (greater than 300 m diameter) lava tube caverns appear to exist on the Moon and could provide substantial safety and cost benefits for lunar bases. Over 40 m of basalt and regolith constitute the lava tube roof and would protect both construction and operations. Constant temperatures of -20 C reduce thermal stress on structures and machines. Base designs need not incorporate heavy shielding, so lightweight materials can be used and construction can be expedited. Identification and characterization of lava tube caverns can be incorporated into current precursor lunar mission plans. Some searches can even be done from Earth. Specific recommendations for lunar lava tube search and exploration are (1) an Earth-based radar interferometer, (2) an Earth-penetrating radar (EPR) orbiter, (3) kinetic penetrators for lunar lava tube confirmation, (4) a 'Moon Bat' hovering rocket vehicle, and (5) the use of other proposed landers and orbiters to help find lunar lava tubes.

X-ray tube current control

International Nuclear Information System (INIS)

Dupuis, W.A.; Resnick, T.A.

1982-01-01

A closed loop feedback system for controlling the current output of an x-ray tube. The system has circuitry for improving the transient response and stability of the x-ray tube current over a substantial nonlinear portion of the tube current production characteristic. The system includes a reference generator for applying adjustable step function reference signals representing desired tube currents. The system also includes means for instantaneous sensing of actual tube current. An error detector compares the value of actual and reference tube current and produces an error signal as a function of their difference. The system feedback loop includes amplification circuitry for controlling x-ray tube filament dc voltage to regulate tube current as a function of the error signal value. The system also includes compensation circuitry, between the reference generator and the amplification circuitry, to vary the loop gain of the feedback control system as a function of the reference magnitude

Manipulation and functionalization of nano-tubes: application to boron nitride nano-tubes

International Nuclear Information System (INIS)

Maguer, A.

2007-01-01

This PhD work is divided into two parts dealing with boron nitride (BNNT) and carbon nano-tubes. The first part is about synthesis, purification and chemical functionalization of BNNT. Single-walled BNNT are synthesized by LASER ablation of a hBN target. Improving the synthesis parameters first allowed us to limit the byproducts (hBN, boric acid). A specific purification process was then developed in order to enrich the samples in nano-tubes. Purified samples were then used to develop two new chemical functionalization methods. They both involve chemical molecules that present a high affinity towards the BN network. The use of long chain-substituted quinuclidines and borazines actually allowed the solubilization of BNNT in organic media. Purification and functionalization were developed for single-walled BNNT and were successfully applied to multi-walled BNNT. Sensibility of boron to thermic neutrons finally gave birth to a study about covalent functionalization possibilities of the network. The second part of the PhD work deals with separation of carbon nano-tubes depending on their properties. Microwave irradiation of carbon nano-tubes first allowed the enrichment of initially polydisperse samples in large diameter nano-tubes. A second strategy involving selective interaction between one type of tubes and fullerene micelles was finally envisaged to selectively solubilize carbon nano-tubes with specific electronic properties. (author) [fr

[Prehospital airway management of laryngeal tubes. Should the laryngeal tube S with gastric drain tube be preferred in emergency medicine?].

Science.gov (United States)

Dengler, V; Wilde, P; Byhahn, C; Mack, M G; Schalk, R

2011-02-01

Laryngeal tubes (LT) are increasingly being used for emergency airway management. This article reports on two patients in whom out-of-hospital intubation with a single-lumen LT was associated with massive pulmonary aspiration in one patient and gastric overinflation in the other. In both cases peak inspiratory pressures exceeded the LT leak pressure of approximately 35 mbar. This resulted in gastric inflation and decreased pulmonary compliance and increased inspiratory pressure further, thereby creating a vicious circle. It is therefore recommended that laryngeal tube suction (LTS) should be used in all cases of emergency airway management and a gastric drain tube be inserted through the dedicated second lumen. Apart from gastric overinflation, incorrect LT/LTS placement must be detected and immediately corrected, e.g. in cases of difficult or impossible gastric tube placement, permanent drainage of air from the gastric tube, decreasing minute ventilation or an ascending capnography curve.

Molybdenum Tube Characterization report

Energy Technology Data Exchange (ETDEWEB)

Beaux II, Miles Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-02-07

Chemical vapor deposition (CVD) techniques have been utilized to produce free-standing molybdenum tubes with the end goal of nuclear fuel clad applications. In order to produce tubes with properties desirable for this application, deposition rates were lowered requiring long deposition durations on the order of 50 hours. Standard CVD methods as well as fluidized-bed CVD (FBCVD) methods were applied towards these objectives. Characterization of the tubes produced in this manner revealed material suitable for fuel clad applications, but lacking necessary uniformity across the length of the tubes. The production of freestanding Mo tubes that possess the desired properties across their entire length represents an engineering challenge that can be overcome in a next iteration of the deposition system.

Apparatus for forming an explosively expanded tube-tube sheet joint

International Nuclear Information System (INIS)

Schroeder, J.W.

1984-01-01

The invention relates to apparatus for expanding a tube into a bore formed in a tube sheet. According to the invention, a primary explosive containing a relatively high number of grains of explosive per unit length extends within the tube coextensive with that portion of the tube to be expanded. An energy transfer cord extends between a detonator and the primary explosive and includes a relatively low number of grains of explosive per unit length which are insufficient to detonate the primary explosive. The transfer cord is covered by a sheath to contain the debris and gases associated with the explosion of the explosive therein. A booster extends between the energy transfer cord and the primary explosive and contains an explosive which can be detonated by the explosive in the energy transfer cord and can, upon exploding, in turn detonate the primary explosive. (author)

Failure analysis of boiler tube

International Nuclear Information System (INIS)

Mehmood, K.; Siddiqui, A.R.

2007-01-01

Boiler tubes are energy conversion components where heat energy is used to convert water into high pressure superheated steam, which is then delivered to a turbine for electric power generation in thermal power plants or to run plant and machineries in a process or manufacturing industry. It was reported that one of the tubes of a fire-tube boiler used in a local industry had leakage after the formation of pits at the external surface of the tube. The inner side of the fire tube was working with hot flue gasses with a pressure of 10 Kg/cm/sup 2/ and temperature 225 degree C. The outside of the tube was surrounded by feed water. The purpose of this study was to determine the cause of pits developed at the external surface of the failed boiler tube sample. In the present work boiler tube samples of steel grade ASTM AI61/ASTM A192 were analyzed using metallographic analysis, chemical analysis, and mechanical testing. It was concluded that the appearance of defects on the boiler tube sample indicates cavitation type corrosion failure. Cavitation damage superficially resembled pitting, but surface appeared considerably rougher and had many closely spaced pits. (author)

Neural Tube Defects

Science.gov (United States)

Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

Importance of crevices formed between tubes and tube plate for the operational behaviour of heat exchangers

International Nuclear Information System (INIS)

Achten, N.; Herbsleb, G.; Wieling, N.

1986-01-01

It must be guaranteed by construction and manufacture of heat exchangers that primary and secondary medium are completely separated from each other. When this requirement is fullfilled, the operational use of heat exchangers can be impaired by corrosion reactions within the crevice formed between tube and tube plate which may result in corrosion damage. The various techniques which are in use to connect tubes and tube plate and which are described in the present report, must be valued with respect to the tightness of the connection as well as to the formation of crevices between tubes and tube plate. Corrosion resistant copperbase alloys and stainless steels are the most important materials which are in use for the construction of heat exchangers. The mechanisms of crevice corrosion with unalloyed and low alloy carbon steels, stainless steels, and mixed connections between tube and tube plate with these materials are described in detail. Crevice corrosion may be caused also by the formation of galvanic cells between materials of differing electrochemical response. Furthermore, the concentration of aggressive media in crevices between tubes and tube plate can lead to corrosion damage of heat exchanger tubes. For the service operation of heat exchangers without any hazard of corrosion damage in crevices between tubes and tube plate, such crevices must be avoided by proper construction and manufacture. As a model for suitable measures to avoid crevices, the manufacture of steam generators for PWR's is described. (orig.) [de

A Study on the Profile Change Measurement of Steam Generator Tubes with Tube Expansion Methods

International Nuclear Information System (INIS)

Kim, Young Kyu; Song Myung Ho; Choi, Myung Sik

2011-01-01

Steam generator tubes for nuclear power plants contain the local shape transitions on their inner or outer surface such as dent, bulge, over-expansion, eccentricity, deflection, and so on by the application of physical force during the tube manufacturing and steam generator assembling and by the sludge (that is, corrosion products) produced during the plant operation. The structural integrity of tubes will be degraded by generating the corrosive crack at that location. The profilometry using the traditional bobbin probes which are currently applied for measuring the profile change of tubes gives us basic information such as axial locations and average magnitudes of deformations. However, the three-dimensional quantitative evaluation on circumferential locations, distributional angle, and size of deformations will have to be conducted to understand the effects of residual stresses increased by local deformations on corrosive cracking of tubes. Steam generator tubes of Korean standard nuclear power plants expanded within their tube-sheets by the explosive expansion method and suffered from corrosive cracks in the early stage of power operation. Thus, local deformations of steam generator tubes at the top of tube-sheet were measured with an advanced rotating probe and a laser profiling system for the two cases where the tubes expanded by the explosive expansion method and hydraulic expansion. Also, the trends of eccentricity, deflection, and over-expansion of tubes were evaluated. The advanced eddy current profilometry was confirmed to provide accurate information of local deformations compared with laser profilometry

Procedure and device for extracting the end of a tube inserted into a hole in a tube plate

International Nuclear Information System (INIS)

1980-01-01

When constructing heat exchangers and steam generators, particularly in the construction of steam generators for nuclear power stations, many small diameter tubes have to be secured into a very thick tube plate for instance 600 mm thick. This crimping or expanding of the tube is generally performed by rolling the internal surface of the tube inside a hole drilled right through the tube plate and slightly greater in diameter than the external diameter of the tube before the tube is rolled. To check the tubes for defects, it is necessary to extract certain tubes from the tube plate in order to move the tube to a testing and inspection point and examine the part of it that was secured in the plate hole. The invention concerns the uncrimping of these tubes [fr

Radiation-resistant camera tube

International Nuclear Information System (INIS)

Kuwahata, Takao; Manabe, Sohei; Makishima, Yasuhiro

1982-01-01

It was a long time ago that Toshiba launched on manufacturing black-and-white radiation-resistant camera tubes employing nonbrowning face-plate glass for ITV cameras used in nuclear power plants. Now in compliance with the increasing demand in nuclear power field, the Company is at grips with the development of radiation-resistant single color-camera tubes incorporating a color-stripe filter for color ITV cameras used under radiation environment. Herein represented are the results of experiments on characteristics of materials for single color-camera tubes and prospects for commercialization of the tubes. (author)

Jose Cabrera (Zorita) tube examination

International Nuclear Information System (INIS)

Kuchirka, P.J.

1986-01-01

Jose Cabrera (Zorita) tube examination procedures are discussed. This plant continues to use phosphate water chemistry (sodium/phosphate ratio = 2.1). Three hot leg tube segments were pulled from the Jose Cabera (Zorita) plant in 1985. One tube had a field EC indication on the OD at the first tube support plate and the other two had field EC indications on their ID about 3 inches above the bottom of the tube sheet. All three tubes were initially sent to Battelle for preliminary NDE and decontamination. Segments of two tubes were sent to Westinghouse for destructive examination. The results of the laboratory eddy current and radiographic examinations are given. The results of the visual examinations are also given. The tube with OD indications was destructively examined and shallow intergranular pitting and intergranular attack, up to 2 mils deep, were found on the OD in the tube sheet region. Local areas of IGA, up to 5 mils deep, were found on the OD within the tube support plate region. A summary of this information together with supporting micrographs is given. It was hypothesized that a caustic crevice environment was the cause of this mild degradation. Shallow areas of thinning or wastage, up to 3 mils, were found just above the top of the tube sheet in the sludge pile region. Even more shallow wastage was found at the edges of support plate locations. This wastage is believed to be the remnant of early plant chemistry when a higher sodium/phosphate ratio and higher phosphate concentration were allowed

The effect of tube-support interaction on the dynamic response of heat exchanger tubes

International Nuclear Information System (INIS)

Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

1977-01-01

To avoid detrimental tube vibration in heat exchangers, resonant conditions and instabilitites must be avoided, and/or peak dynamic amplitudes must not exceed allowable limits. In attempting a theoretical analysis, questions arise as to the effects of tube/support interaction on tube vibrational characteristics (i.e. resonant frequencies, modes, damping) and response amplitude. As a part of ANL's Flow-Induced Vibration Program in support of the Clinch River Breeder Reactor Plant (CRBRP) steam generator design activity, tube/support interaction experiments are being performed not only to gain the insight into the dynamic behavior of CRBRP steam generator tubes, but also to provide the basis for developing design guidance. Test results were compared with anaytical results based on multispan tube with 'knife-edge' supports at the support locations. (Auth.)

Twin-tubes: 3D tracking based on the ATLAS muon drift tubes

International Nuclear Information System (INIS)

Woudstra, M.; Bobbink, G.J.; Eldik, N. van; Graaf, H. van der; Kluit, P.; Koutsman, A.; Limper, M.; Linde, F.; Massaro, G.; Snuverink, J.; Vreeswijk, M.; Groenstege, H.; Koopstra, J.; Mos, S.; Rewiersma, P.; Timmermans, C.; Dijkema, J.

2006-01-01

The Monitored Drift Tubes (MDTs) of the ATLAS Muon Spectrometer have been paired to form so-called twin-tubes to measure the coordinate which runs along the wire direction. This modification endows the MDTs with full 3D track reconstruction using specially designed electronic boards. The performance of the twin-tubes has been measured for an equipped MDT chamber at the ATLAS Muon Cosmic Ray Test Stand at NIKHEF. The efficiency of a twin-tube has been determined to be 99.8%, and the measured resolution 17 cm per hit. By equipping one multilayer consisting of three layers and combining the measurements a resolution of 10 cm has been obtained

Free Piston Double Diaphragm Shock Tube

OpenAIRE

OGURA, Eiji; FUNABIKI, Katsushi; SATO, Shunichi; ABE, Takashi; 小倉, 栄二; 船曳, 勝之; 佐藤, 俊逸; 安部, 隆士

1997-01-01

A free piston double diaphragm shock tube was newly developed for generation of high Mach number shock wave. Its characteristics was investigated for various operation parameters; such as a strength of the diaphragm at the end of the comparession tube, an initial pressure of low pressure tube, an initial pressure of medium pressure tube and the volume of compression tube. Under the restriction of fixed pressures for the driver high pressure tube (32×10^5Pa) and the low pressure tube (40Pa) in...

Liquid-Nitrogen Test for Blocked Tubes

Science.gov (United States)

Wagner, W. R.

1984-01-01

Nondestructive test identifies obstructed tube in array of parallel tubes. Trickle of liquid nitrogen allowed to flow through tube array until array accumulates substantial formation of frost from moisture in air. Flow stopped and warm air introduced into inlet manifold to heat tubes in array. Tubes still frosted after others defrosted identified as obstructed tubes. Applications include inspection of flow systems having parallel legs.

Development and Technology Transfer of the Syncro Blue Tube (Gabriel) Magnetically Guided Feeding Tube

Science.gov (United States)

2017-06-01

suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188...the tube to the 110 cm mark. At the 110 cm mark, secure the tube with medical tape and remove the stylet completely allowing enough tube slack ...and it provides slack that allows tube to advance distally by the effect of natural peristalsis on the bolus-sized balloon. Results: Most feeding

X-ray tubes

International Nuclear Information System (INIS)

Young, R.W.

1979-01-01

A form of x-ray tube is described which provides satisfactory focussing of the electron beam when the beam extends for several feet from gun to target. Such a tube can be used for computerised tomographic scanning. (UK)

X-ray tube

International Nuclear Information System (INIS)

Webley, R.S.

1975-01-01

The object of the invention described is to provide an X-ray tube providing a scanned X-ray output which does not require a scanned electron beam. This is obtained by an X-ray tube including an anode which is rotatable about an axis, and a source of a beam of energy, for example an electron beam, arranged to impinge on a surface of the anode to generate X-radiation substantially at the region of incidence on the anode surface. The anode is rotatable about the axis to move the region of incidence over the surface. The anode is so shaped that the rotation causes the region of incidence to move in a predetermined manner relative to fixed parts of the tube so that the generated X-radiation is scanned in a predetermined manner relative to the tube. (UK)

Pump element for a tube pump

DEFF Research Database (Denmark)

2011-01-01

The invention relates to a tube pump comprising a tube and a pump element inserted in the tube, where the pump element comprises a rod element and a first and a second non-return valve member positioned a distance apart on the rod element. The valve members are oriented in the same direction...... relative to the rod element so as to allow for a fluid flow in the tube through the first valve member, along the rod element, and through the second valve member. The tube comprises an at least partly flexible tube portion between the valve members such that a repeated deformation of the flexible tube...... portion acts to alternately close and open the valve members thereby generating a fluid flow through the tube. The invention further relates to a pump element comprising at least two non-return valve members connected by a rod element, and for insertion in an at least partly flexible tube in such tube...

Ultrasonic measurement of gap between calandria tube and liquid injection shutdown system tube in PHWR

International Nuclear Information System (INIS)

Kim, Tae Ryong; Sohn, Seok Man; Lee, Jun Shin; Lee, Sun Ki; Lee, Jong Po

2001-01-01

Sag of CT or liquid injection shutdown system tubes in pressurized heavy water reactor is known to occur due to irradiation creep and growth during plant operation. When the sag of CT is big enough, the CT tube possibly comes in contact with liquid injection shutdown system tube (LIN) crossing beneath the CT, which subsequently may prevent the safe operation. It is therefore necessary to check the gap between the two tubes in order to confirm no contacts when using a proper measure periodically during the plant life. An ultrasonic gap measuring probe assembly which can be fed through viewing port installed on the calandria was developed and utilized to measure the sags of both tubes in a pressurized heavy water reactor in Korea. It was found that the centerlines of CT and LIN can be precisely detected by ultrasonic wave. The gaps between two tubes were easily obtained from the relative distance of the measured centerline elevations of the tubes. But the measured gap data observed at the viewing port were actually not the data at the crossing point of CT and LIN. To get the actual gap between two tubes, mathematical modeling for the deflection curves of two tubes was used. The sags of CT and LIN tubes were also obtained by comparison of the present centerlines with the initial elevations at the beginning of plant operation. The gaps between two tubes in the unmeasurable regions were calculated based on the measurement data and the channel power distribution

Tubing misconnections: normalization of deviance.

Science.gov (United States)

Simmons, Debora; Symes, Lene; Guenter, Peggi; Graves, Krisanne

2011-06-01

Accidental connection of an enteral system to an intravenous (IV) system frequently results in the death of the patient. Misconnections are commonly attributed to the presence of universal connectors found in the majority of patient care tubing systems. Universal connectors allow for tubing misconnections between physiologically incompatible systems. The purpose of this review of case studies of tubing misconnections and of current expert recommendations for safe tubing connections was to answer the following questions: In tubing connections that have the potential for misconnections between enteral and IV tubing, what are the threats to safety? What are patient outcomes following misconnections between enteral and IV tubing? What are the current recommendations for preventing misconnections between enteral and IV tubing? Following an extensive literature search and guided by 2 models of threats and errors, the authors analyzed case studies and expert opinions to identify technical, organizational, and human errors; patient-related threats; patient outcomes; and recommendations. A total of 116 case studies were found in 34 publications. Each involved misconnections of tubes carrying feedings, intended for enteral routes, to IV lines. Overwhelmingly, the recommendations were for redesign to eliminate universal connectors and prevent misconnections. Other recommendations were made, but the analysis indicates they would not prevent all misconnections. This review of the published case studies and current expert recommendations supports a redesign of connectors to ensure incompatibility between enteral and IV systems. Despite the cumulative evidence, little progress has been made to safeguard patients from tubing misconnections.

Resolution of lava tubes with ground penetrating radar: preliminary results from the TubeX project

Science.gov (United States)

Esmaeili, S.; Kruse, S.; Garry, W. B.; Whelley, P.; Young, K.; Jazayeri, S.; Bell, E.; Paylor, R.

2017-12-01

As early as the mid 1970's it was postulated that planetary tubes or caves on other planetary bodies (i.e., the Moon or Mars) could provide safe havens for human crews, protect life and shield equipment from harmful radiation, rapidly fluctuating surface temperatures, and even meteorite impacts. What is not clear, however, are the exploration methods necessary to evaluate a potential tube-rich environment to locate suitable tubes suitable for human habitation. We seek to address this knowledge gap using a suite of instruments to detect and document tubes in a terrestrial analog study at Lava Beds National Monument, California, USA. Here we describe the results of ground penetrating radar (GPR) profiles and light detection and ranging (LiDAR) scans. Surveys were conducted from the surface and within four lava tubes (Hercules Leg, Skull, Valentine and, Indian Well Caves) with varying flow composition, shape, and complexity. Results are shown across segments of these tubes where the tubes are 10 m in height and the ceilings are 1 - 10 m below the surface. The GPR profiles over the tubes are, as expected, complex, due to scattering from fractures in roof material and three-dimensional heterogeneities. Point clouds derived from the LiDAR scans of both the interior and exterior of the lava tubes provide precise positioning of the tube geometry and depth of the ceiling and floor with respect to the surface topography. GPR profiles over LiDAR-mapped tube cross-sections are presented and compared against synthetic models of radar response to the measured geometry. This comparison will help to better understand the origins of characteristic features in the radar profiles. We seek to identify the optimal data processing and migration approaches to aid lava tube exploration of planetary surfaces.

The effect of tube rupture location on the consequences of multiple steam generator tube rupture event

International Nuclear Information System (INIS)

Jeong, Ji Hwan; Kweon, Young Chul

2002-01-01

A multiple steam generator tube rupture (MSGTR) event has never occurred in the commercial operation of nuclear reactors while single steam generator tube rupture (SGTR) events are reported to occur every 2 years. As there has been no occurrence of a MSGTR event, the understanding of transients and consequences of this event is very limited. In this study, a postulated MSGTR event in an advanced power reactor 1400 (APR 1400) is analyzed using the thermal-hydraulic system code, MARS1.4. The APR 1400 is a two-loop, 3893 MWt, PWR proposed to be built in 2010. The present study aims to understand the effects of rupture location in heat transfer tubes following a MSGTR event. The effects of five tube rupture locations are compared with each other. The comparison shows that the response of APR1400 allows the shortest time for operator action following a tube rupture in the vicinity of the hot-leg side tube sheet and allows the longest time following a tube rupture at the tube top. The MSSV lift time for rupture at the tube-top is evaluated as 24.5% larger than that for rupture at the hot-leg side tube sheet

Experimental study of tube/support impact forces in multi-span PWR steam generator tubes

International Nuclear Information System (INIS)

Axisa, F.; Desseaux, A.; Gibert, R.J.

1984-12-01

The vibro-impact response of a straight part of a steam generator tube is investigated experimentally and using numerical simulation with the aim to relate tube overall dynamics with excitation and tube-support clearance. Configuration studied here corresponds to the tube being excited in only one direction at its first resonance presenting an antinode of vibration at the impacted support. Tests show namely that midspan displacement of tube is almost proportional to excitation level and clearance. Impact forces averaged over a cycle of vibration are almost proportional to excitation and poorly dependent on clearance. Results of numerical simulation are in fairly good agreement with test results

YouTube and 'psychiatry'.

Science.gov (United States)

Gordon, Robert; Miller, John; Collins, Noel

2015-12-01

YouTube is a video-sharing website that is increasingly used to share and disseminate health-related information, particularly among younger people. There are reports that social media sites, such as YouTube, are being used to communicate an anti-psychiatry message but this has never been confirmed in any published analysis of YouTube clip content. This descriptive study revealed that the representation of 'psychiatry' during summer 2012 was predominantly negative. A subsequent smaller re-analysis suggests that the negative portrayal of 'psychiatry' on YouTube is a stable phenomenon. The significance of this and how it could be addressed are discussed.

YouTube as an information source for pediatric adenotonsillectomy and ear tube surgery.

Science.gov (United States)

Sorensen, Jeffrey A; Pusz, Max D; Brietzke, Scott E

2014-01-01

Assess the overall quality of information on adenotonsillectomy and ear tube surgery presented on YouTube (www.youtube.com) from the perspective of a parent or patient searching for information on surgery. The YouTube website was systematically searched on select dates with a formal search strategy to identify videos pertaining to pediatric adenotonsillectomy and ear tube surgery. Only videos with at least 5 (ear tube surgery) or 10 (adenotonsillectomy) views per day were included. Each video was viewed and scored by two independent scorers. Videos were categorized by goal and scored for video/audio quality, accuracy, comprehensiveness, and procedure-specific content. Cross-sectional study. Public domain website. Fifty-five videos were scored for adenotonsillectomy and forty-seven for ear tube surgery. The most common category was educational (65.3%) followed by testimonial (28.4%), and news program (9.8%). Testimonials were more common for adenotonsillectomy than ear tube surgery (41.8% vs. 12.8%, p=0.001). Testimonials had a significantly lower mean accuracy (2.23 vs. 2.62, p=0.02), comprehensiveness (1.71 vs. 2.22, p=0.007), and TA specific content (0.64 vs. 1.69, p=0.001) score than educational type videos. Only six videos (5.9%) received high scores in both video/audio quality and accuracy/comprehensiveness of content. There was no significant association between the accuracy and comprehensive score and views, posted "likes", posted "dislikes", and likes/dislikes ratio. There was an association between "likes" and mean video quality (Spearman's rho=0.262, p=0.008). Parents/patients searching YouTube for information on pediatric adenotonsillectomy and ear tube surgery will generally encounter low quality information with testimonials being common but of significantly lower quality. Viewer perceived quality ("likes") did not correlate to formally scored content quality. Published by Elsevier Ireland Ltd.

Development of heat treated Zr-2.5% Nb alloy tubes for pressure tubes

International Nuclear Information System (INIS)

Saibaba, N.; Jha, S.K.; Tonpe, S.

2011-01-01

Zr-2.5% Nb alloy is the candidate material for pressure tubes of Pressurized Heavy Water Reactors (PHWR), and are manufactured in cold working condition while heat treated pressure tubes are used in RBMK and FUGEN type of reactors. The diametral creep of these tubes is the life limiting factor. This paper presents the extensive work carried out for the optimization of process parameters to manufacture heat treated Zr-2.5% Nb pressure tubes. Extensive dilactometry study was carried out to establish the transus temperature for the alloy and the effect of soaking temperature and cooling rate on the microstructure was characterized. On the basis of the study, water quenching (at 883 deg C) in the a b region with 20-25% primary a phase was selected, further cold worked, aged and finally autoclaved. Mechanical properties of the finished tubes were found to be comparable to the cold worked route. Large number of full sized tubes of about 700 - 800 mm long was produced to establish the repeatability. (author)

Inflation-deflation test as a predictor of aditus patency in patients with chronic suppurative otitis media.

Science.gov (United States)

Kurien, Regi; Chrisolyte, Shipra; Rupa, V

2009-09-01

To assess eustachian tubal function (ETF) preoperatively in patients with chronic suppurative otitis media (CSOM) with central perforation by performing the inflation-deflation test. To correlate the results of the inflation-deflation test with the finding of aditus patency or block in patients with CSOM STUDY DESIGN: Prospective, cohort Tertiary care hospital Eighty adult patients with chronic suppurative otitis media and central perforation were recruited into the study. There were 45 males and 35 females. All patients underwent preoperative inflation-deflation test followed by cortical mastoidectomy and tympanoplasty. The patency of the aditus was assessed intraoperatively. Equalization of pressure on inflation-deflation test and intraoperative assessment of aditus patency Of a total of 80 patients, 49 patients were found to have discharging ears and 31 had dry ears at the time of surgery. In dry ears the inflation-deflation test had a sensitivity of 93% in predicting aditus patency although the specificity was lower at 67%. In discharging ears the sensitivity in predicting aditus patency was 72% and the specificity was 67%. The eustachian tube inflation-deflation test is a sensitive test for predicting aditus patency in patients with dry ears but less so in patients with discharging ears. Hence, it could be used in the former to avoid unnecessary exploration of the mastoid.

An investigation on SA 213-Tube to SA 387-Tube plate using friction welding process

Energy Technology Data Exchange (ETDEWEB)

Rajan, S. Pandia; Kumaraswamidhas, L. A. [Indian Institute of Technology, Jharkhand (India); Kumaran, S. Senthil [RVS School of Engineering and Technology, Tamil Nadu (India); Muthukumaran, S. [National Institute of Technology, Tamil Nadu (India)

2016-01-15

Friction welding of tube to tube plate using an external tool (FWTPET) is a relatively newer solid state welding process used for joining tube to tube plate of either similar or dissimilar materials with enhanced mechanical and metallurgical properties. In the present study, FWTPET has been used to weld SA 213 (Grade T12) tube with SA 387 (Grade 22) tube plate. The welded samples are found to have satisfactory joint strength and the Energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) study showed that inter metallic compound is absent in the weld zone. The different weld joints have been identified and the phase composition is found using EDX and XRD. Microstructures have been analyzed using optical and Scanning electron microscopy (SEM). The mechanical properties such as hardness, compressive shear strength and peel test for different weld conditions are studied and the hardness survey revealed that there is increase in hardness at the weld interface due to grain refinement. The corrosion behavior for different weld conditions have been analyzed and the weld zone is found to have better corrosion resistance due to the influence of the grain refinement after FWTPET welding process. Hence, the present investigation is carried out to study the behavior of friction welded dissimilar joints of SA 213 tube and SA 387 tube plate joints and the results are presented. The present study confirms that a high quality tube to tube plate joint can be achieved using FWTPET process at 1120 rpm.

PWR steam generator tubing sample library

International Nuclear Information System (INIS)

Anon.

1987-01-01

In order to compile the tubing sample library, two approaches were employed: (a) tubing sample replication by either chemical or mechanical means, based on field tube data and metallography reports for tubes already destructively examined; and (b) acquisition of field tubes removed from operating or retired steam generators. In addition, a unique mercury modeling concept is in use to guide the selection of replica samples. A compendium was compiled that summarizes field observations and morphologies of steam generator tube degradation types based on available NDE, destructive examinations, and field reports. This compendium was used in selecting candidate degradation types that were manufactured for inclusion in the tube library

Steam generator tube performance

International Nuclear Information System (INIS)

Tatone, O.S.; Pathania, R.S.

1984-10-01

A review of the performance of steam generator tubes in 116 water-cooled nuclear power reactors showed that tubes were plugged at 54 (46 percent) of the reactors. The number of tubes removed from service decreased from 4 692 (0.30 percent) in 1981 to 3 222 (0.20 percent) in 1982. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that have used only volatile treatment, with or without condensate demineralization

Steam generator tube performance

International Nuclear Information System (INIS)

Tatone, O.S.; Tapping, R.L.; Stipan, L.

1992-03-01

A survey of steam generator operating experience for 1986 has been carried out for 184 pressurized water and pressurized heavy-water reactors, and 1 water-cooled, graphite-moderated reactor. Tubes were plugged at 75 of the reactors (40.5%). In 1986, 3737 tubes were plugged (0.14% of those in service) and 3148 tubes were repaired by sleeving. A small number of reactors accounted for the bulk of the plugged tubes, a phenomenon consistent with previous years. For 1986, the available tubesheet sludge data for 38 reactors has been compiled into tabular form, and sludge/deposit data will be incorporated into all future surveys

Sealed ion accelerator tubes (survey)

International Nuclear Information System (INIS)

Voitsik, L.R.

1985-01-01

The first publications on developing commercial models of small-scale sealed accelerator tubes in which neutrons are generated appeared in the foreign press in 1954 to 1957; they were very brief and were advertising-oriented. The tubes were designed for neutron logging of oil wells instead of ampule neutron sources (Po + Be, Ra + Be). Later, instruments of this type began to be called neutron tubes from the resulting neutron radiation that they gave off. In Soviet Union a neutron tube was developed in 1958 in connection with the development of the pulsed neutron-neutron method of studying the geological profile of oil wells. At that time the tube developed was intended, in the view of its inventors, to replace standard isotope sources with constant neutron yield. A fairly detailed survey of neutron tubes was made in the studies. 8 refs., 8 figs

Steam generator tube integrity program

International Nuclear Information System (INIS)

Dierks, D.R.; Shack, W.J.; Muscara, J.

1996-01-01

A new research program on steam generator tubing degradation is being sponsored by the U.S. Nuclear Regulatory Commission (NRC) at Argonne National Laboratory. This program is intended to support a performance-based steam generator tube integrity rule. Critical areas addressed by the program include evaluation of the processes used for the in-service inspection of steam generator tubes and recommendations for improving the reliability and accuracy of inspections; validation and improvement of correlations for evaluating integrity and leakage of degraded steam generator tubes, and validation and improvement of correlations and models for predicting degradation in steam generator tubes as aging occurs. The studies will focus on mill-annealed Alloy 600 tubing, however, tests will also be performed on replacement materials such as thermally-treated Alloy 600 or 690. An overview of the technical work planned for the program is given

Tube plug removal machine

International Nuclear Information System (INIS)

Hawkins, P.J.

1987-01-01

In a nuclear steam generator wherein some faulty tubes have been isolated by mechanical plugging, to remove a selected plug without damaging the associated tube, a plug removal machine is used. The machine drills into a plug portion with a tap drill bit having a drill portion a tap portion and a threaded portion, engaging that plug portion with the threaded portion after the drilled hole has been threaded by the tap portion thereof, and removing a portion of the plug in the tube with a counterbore drill bit mounted concentrically about the tap drill bit. A trip pin and trip spline disengage the tap drill bit from the motor. The counterbore drill bit is thereafter self-centered with respect to the tube and plug about the now stationary tap drill bit. After a portion of the plug has been removed by the counterbore drill bit, pulling on the top drill bit by grippers on slots will remove the remaining plug portion from the tube. (author)

Falling film evaporation on a tube bundle with plain and enhanced tubes

International Nuclear Information System (INIS)

Habert, M.

2009-04-01

The complexities of two-phase flow and evaporation on a tube bundle present important problems in the design of heat exchangers and the understanding of the physical phenomena taking place. The development of structured surfaces to enhance boiling heat transfer and thus reduce the size of evaporators adds another level of complexity to the modeling of such heat exchangers. Horizontal falling film evaporators have the potential to be widely used in large refrigeration systems and heat pumps, in the petrochemical industry and for sea water desalination units, but there is a need to improve the understanding of falling film evaporation mechanisms to provide accurate thermal design methods. The characterization of the effect of enhanced surfaces on the boiling phenomena occurring in falling film evaporators is thus expected to increase and optimize the performance of a tube bundle. In this work, the existing LTCM falling film facility was modified and instrumented to perform falling film evaporation measurements on single tube row and a small tube bundle. Four types of tubes were tested including: a plain tube, an enhanced condensing tube (Gewa-C+LW) and two enhanced boiling tubes (Turbo-EDE2 and Gewa-B4) to extend the existing database. The current investigation includes results for two refrigerants, R134a and R236fa, at a saturation temperature of T sat = 5 °C, liquid film Reynolds numbers ranging from 0 to 3000, at heat fluxes between 20 and 60 kW/m² in pool boiling and falling film configurations. Measurements of the local heat transfer coefficient were obtained and utilized to improve the current prediction methods. Finally, the understanding of the physical phenomena governing the falling film evaporation of liquid refrigerants has been improved. Furthermore, a method for predicting the onset of dry patch formation has been developed and a local heat transfer prediction method for falling film evaporation based on a large experimental database has been proposed

Steam generator tube performance

International Nuclear Information System (INIS)

Tatone, O.S.; Pathania, R.S.

1982-04-01

The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1980. Tube defects occurred at 38% of the 97 reactors surveyed. This is a marginal improvement over 1979 when defects occurred at 41% of the reactors. The number of failed tubes was also lower, 0.14% of the tubes in service in 1980 compared with 0.20% of those in service in 1979. Analysis of the causes of these failures indicates that stress corrosion cracking was the leading failure mechanism. Reactors that used all-volatile treatment of secondary water, with or without full-flow condensate demineralization since start-up showed the lowest incidence of corrosion-related defects

The dynamic single-tube concept; Le mono-tube dynamique

Energy Technology Data Exchange (ETDEWEB)

Rivet, P. [Ste MC International (France)

1997-12-31

In the framework of greenhouse gas emission reduction and the utilization of cooling intermediate fluids with indirect refrigerating systems, a new concept of dynamical single-tube has been developed, which allows for the simultaneous cold distribution from a centralized plant towards various required temperature systems (as for example in a supermarket refrigerating system) with optimized efficiency, fluid flow and defrosting conditions; moreover, the dynamic single-tube concept is very well adapted to two-phase flows

Fuel assembly and fuel cladding tube

International Nuclear Information System (INIS)

Tsutsumi, Shinro; Ito, Ken-ichi; Inagaki, Masatoshi; Nakajima, Junjiro.

1996-01-01

A fuel cladding tube is a zirconium liner tube formed by lining a pure zirconium layer on the inner side of a zirconium alloy tube. The fuel cladding tube is formed by extrusion molding of a composite billet formed by inserting a pure zirconium billet into a zirconium alloy billet. Accordingly, the pure zirconium layer and the zirconium alloy tube are strongly joined by metal bond. The fuel cladding tube has an external oxide film on the outer surface of the zirconium alloy tube and an internal oxide film on the inner side of the pure zirconium layer. The external oxide film has a thickness preferably of about 1μm. The internal oxide film has a thickness of not more than 10μm, preferably, from 1 to 5μm. With such a constitution, flaws to be formed on both inner and outer surfaces of the cladding tube upon assembling a fuel assembly can be reduced thereby enabling to reduce the amount of hydrogen absorbed to the cladding tube. (I.N.)

Comparison of digoxin concentration in plastic serum tubes with clot activator and heparinized plasma tubes.

Science.gov (United States)

Dukić, Lora; Simundić, Ana-Maria; Malogorski, Davorin

2014-01-01

Sample type recommended by the manufacturer for the digoxin Abbott assay is either serum collected in glass tubes or plasma (sodium heparin, lithium heparin, citrate, EDTA or oxalate as anticoagulant) collected in plastic tubes. In our hospital samples are collected in plastic tubes. Our hypothesis was that the serum sample collected in plastic serum tube can be used interchangeably with plasma sample for measurement of digoxin concentration. Our aim was verification of plastic serum tubes for determination of digoxin concentration. Concentration of digoxin was determined simultaneously in 26 venous blood plasma (plastic Vacuette, LH Lithium heparin) and serum (plastic Vacuette, Z Serum Clot activator; both Greiner Bio-One GmbH, Kremsmünster, Austria) samples, on Abbott AxSYM analyzer using the original Abbott Digoxin III assay (Abbott, Wiesbaden, Germany). Tube comparability was assessed using the Passing Bablok regression and Bland-Altman plot. Serum and plasma digoxin concentrations are comparable. Passing Bablok intercept (0.08 [95% CI = -0.10 to 0.20]) and slope (0.99 [95% CI = 0.92 to 1.11]) showed there is no constant or proportional error. Blood samples drawn in plastic serum tubes and plastic plasma tubes can be interchangeably used for determination of digoxin concentration.

Dermatology on YouTube.

Science.gov (United States)

Boyers, Lindsay N; Quest, Tyler; Karimkhani, Chante; Connett, Jessica; Dellavalle, Robert P

2014-06-15

YouTube, reaches upwards of six billion users on a monthly basis and is a unique source of information distribution and communication. Although the influence of YouTube on personal health decision-making is well established, this study assessed the type of content and viewership on a broad scope of dermatology related content on YouTube. Select terms (i.e. dermatology, sun protection, skin cancer, skin cancer awareness, and skin conditions) were searched on YouTube. Overall, the results included 100 videos with over 47 million viewers. Advocacy was the most prevalent content type at 24% of the total search results. These 100 videos were "shared" a total of 101,173 times and have driven 6,325 subscriptions to distinct YouTube user pages. Of the total videos, 35% were uploaded by or featured an MD/DO/PhD in dermatology or other specialty/field, 2% FNP/PA, 1% RN, and 62% other. As one of the most trafficked global sites on the Internet, YouTube is a valuable resource for dermatologists, physicians in other specialties, and the general public to share their dermatology-related content and gain subscribers. However, challenges of accessing and determining evidence-based data remain an issue.

Bacterial Biofilms in Jones Tubes.

Science.gov (United States)

Ahn, Eric S; Hauck, Matthew J; Kirk Harris, Jonathan; Robertson, Charles E; Dailey, Roger A

To investigate the presence and microbiology of bacterial biofilms on Jones tubes (JTs) by direct visualization with scanning electron microscopy and polymerase chain reaction (PCR) of representative JTs, and to correlate these findings with inflammation and/or infection related to the JT. In this study, prospective case series were performed. JTs were recovered from consecutive patients presenting to clinic for routine cleaning or recurrent irritation/infection. Four tubes were processed for scanning electron microscopy alone to visualize evidence of biofilms. Two tubes underwent PCR alone for bacterial quantification. One tube was divided in half and sent for scanning electron microscopy and PCR. Symptoms related to the JTs were recorded at the time of recovery. Seven tubes were obtained. Five underwent SEM, and 3 out of 5 showed evidence of biofilms (60%). Two of the 3 biofilms demonstrated cocci and the third revealed rods. Three tubes underwent PCR. The predominant bacteria identified were Pseudomonadales (39%), Pseudomonas (16%), and Staphylococcus (14%). Three of the 7 patients (43%) reported irritation and discharge at presentation. Two symptomatic patients, whose tubes were imaged only, revealed biofilms. The third symptomatic patient's tube underwent PCR only, showing predominantly Staphylococcus (56%) and Haemophilus (36%) species. Two of the 4 asymptomatic patients also showed biofilms. All symptomatic patients improved rapidly after tube exchange and steroid antibiotic drops. Bacterial biofilms were variably present on JTs, and did not always correlate with patients' symptoms. Nevertheless, routine JT cleaning is recommended to treat and possibly prevent inflammation caused by biofilms.

Rectangular drift tube characteristics

International Nuclear Information System (INIS)

Denisov, D.S.; Musienko, Yu.V.

1985-01-01

Results on the study of the characteristics of a 50 x 100 mm aluminium drift tube are presented. The tube was filled with argon-methane and argon-isobutane mixtures. With 16 per cent methane concentration the largest deviation from a linear relation between the drift time and the drift path over 50 mm is less than 2 mm. The tube filled with argon-isobutane mixture is capable of operating in a limited streamer mode

Chest tube insertion - series (image)

Science.gov (United States)

Chest tubes are inserted to drain blood, fluid, or air and allow full expansion of the lungs. The tube is placed in the pleural space. The area where the tube will be inserted is numbed (local anesthesia). The patient may also be sedated. The chest ...

Boiling and condensation in microfin tubes

Science.gov (United States)

Schlager, Lynn M.

A general overview of microfin tubes and their applications is presented. Manufacturing processes, commercial availability, experimental heat transfer, and pressure drop data for various refrigerants (including alternative refrigerants and refrigerant-oil mixtures), physical mechanisms of enhancement, and the incorporation of microfin tubes in common heat exchanger configurations are discussed. Microfin tubes, also known by various trade names, are characterized by numerous small fins which typically spiral down the inside wall of tubes at angles ranging from 10 to 30 degrees. The number of fins ranges from 48 to 70 with typical fin heights of 0.12 to 0.30 mm (fin height generally less than 3 percent of the inside diameter of the tube). Fin shapes may vary and the inside surface area of microfin tubes is 10 to 70 percent greater than the area of equivalent smooth tubes. Heat transfer can be enhanced by up to a factor of three with microfin tubes.

Flux tubes at finite temperature

Energy Technology Data Exchange (ETDEWEB)

Cea, Paolo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cuteri, Francesca; Papa, Alessandro [Dipartimento di Fisica, Università della Calabria & INFN-Cosenza,Ponte Bucci, cubo 31C, I-87036 Rende (Cosenza) (Italy)

2016-06-07

The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm ≃1.6/√σ and the temperature is increased towards and above the deconfinement temperature T{sub c}, the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube “evaporation” above T{sub c} has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.

Managing a chest tube and drainage system.

Science.gov (United States)

Durai, Rajaraman; Hoque, Happy; Davies, Tony W

2010-02-01

Intercostal drainage tubes (ie, chest tubes) are inserted to drain the pleural cavity of air, blood, pus, or lymph. The water-seal container connected to the chest tube allows one-way movement of air and liquid from the pleural cavity. The container should not be changed unless it is full, and the chest tube should not be clamped unnecessarily. After a chest tube is inserted, a nurse trained in chest-tube management is responsible for managing the chest tube and drainage system. This entails monitoring the chest-tube position, controlling fluid evacuation, identifying when to change or empty the containers, and caring for the tube and drainage system during patient transport. This article provides an overview of indications, insertion techniques, and management of chest tubes. Copyright 2010 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Strong, corrosion-resistant aluminum tubing

Science.gov (United States)

Reed, M. W.; Adams, F. F.

1980-01-01

When aluminum tubing having good corrosion resistance and postweld strength is needed, type 5083 alloy should be considered. Chemical composition is carefully controlled and can be drawn into thin-wall tubing with excellent mechanical properties. Uses of tubing are in aircraft, boats, docks, and process equipment.

Bottom nozzle to guide tube connection

International Nuclear Information System (INIS)

Bryan, W.J.

1991-01-01

This patent describes a nuclear fuel assembly which includes an upper end fitting and a lower end fitting spaced therefrom and connected thereto by elongated guide tubes of one alloy having an open upper end and a closed lower end with spaced fuel element retaining grids mounted on the guide tubes therebetween, the closed lower ends of the guide tubes including a threaded central passageway and the attachment of the guide tubes to the lower end fitting of another alloy. It comprises: an externally threaded bolt with a first end threadably received in the threaded central passageway of the lower end of the guide tube and a head at the other end of the side of the lower end fitting opposite the guide tube; an interruption in the external threads of the bolt which forms a groove which communicates the interior of the guide tube with the side of the lower end fitting opposite the guide tube and enhances its frictional engagement with the threaded central passageway, thereby to hold and attach the guide tube and lower end fitting firmly together, even through a series of temperature cycles

Development of the double-wall-tube steam generator. Evaluation of inner tube leak detection system

International Nuclear Information System (INIS)

Teraoku, Takuji; Kisohara, Naoyuki

1995-01-01

A double-wall-tube steam generator (DWT-SG) is considered to have possibility of eliminating a secondary heat transport system to realize a reliable and simplified FBR plant. Thus, basic tests for inner/outer tube leak detection and prototypical leak tests by use of the 1MWt DWT-SG model have been performed to evaluate the feasibility of DWT-SG. Their results demonstrated that the inner leak detection system can definitely detect a steam leak from an inner tube flaw. Analyses of the inner tube leak and detection behavior obtained in the 1MWt DWT-SG test enabled to estimate the performance of the inner tube detection system of the commercial DWT-SG system. (author)

Cross-talk in straw tube chambers

Energy Technology Data Exchange (ETDEWEB)

Marzec, J. E-mail: janusz.marzec@ire.pw.edu.pl

2003-05-11

An analytical model of the signal transmission between neighboring straw tubes with resistive cathodes (cross-talk) is presented. The dependence of the cross-talk level on the cathode resistance, tube length, particle detection point, the distance of the tube from the shielding planes, and termination of the tube ends is analyzed.

Cross-talk in straw tube chambers

International Nuclear Information System (INIS)

Marzec, J.

2003-01-01

An analytical model of the signal transmission between neighboring straw tubes with resistive cathodes (cross-talk) is presented. The dependence of the cross-talk level on the cathode resistance, tube length, particle detection point, the distance of the tube from the shielding planes, and termination of the tube ends is analyzed

Tubing cutter for tight spaces

Science.gov (United States)

Girala, A. S.

1980-01-01

Cutter requires few short swings of handle to rotate its cutting edge full 360 around tube. It will cut tubing installed in confined space that prevents free movement of conventional cutter. Cutter is snapped onto tube and held in place by spring-loaded clamp. Screw ratchet advances cutting wheel.

Evaluation of the Effect of Tube Pitch and Surface Alterations on Temperature Field at Sprinkled Tube Bundle

Directory of Open Access Journals (Sweden)

Kracík Petr

2015-01-01

Full Text Available Water flowing on a sprinkled tube bundle forms three basic modes: It is the Droplet mode (liquid drips from one tube to another, the Jet mode (with an increasing flow rate droplets merge into a column and the Membrane (Sheet mode (with further increasing of falling film liquid flow rate columns merge and create sheets between the tubes. With sufficient flow rate sheets merge at this state and the tube bundle is completely covered by a thin liquid film. There are several factors influencing the individual mode types as well as heat transfer. Beside the above mentioned falling film liquid flow rate they are for instance tube diameters, tube pitches in a tube bundle or a physical condition of a falling film liquid. This paper presents a summary of data measured at atmospheric pressure at a tube bundle consisting of copper tubes of 12 milimeters diameter and of the studied tube length one meter. The tubes are positioned horizontally one above another with the tested pitches of 15, 20, 25 and 30 mm and there is a distribution tube placed above them with water flowing out. The thermal gradient of 15–40 has been tested with all pitches where the falling film liquid’s temperature at the inlet of the distribution tube was 15 °C. The liquid was heated during the flow through the exchanger and the temperature of the sprinkled (heater liquid at the inlet of the exchanger with a constant flow rate about 7.2 litres per minute was 40 °C. The tested flow of the falling film liquid ranged from 1.0 to 13.0 litres per minute. Sequences of 180 exposures have been recorded in partial flow rate stages by thermographic camera with record frequency of 30 Hz which were consequently assessed using the Matlab programme. This paper presents results achieved at the above mentioned pitches and at three types of tube bundle surfaces.

An investigation on mechanical property of commercial copper tube to aluminium 2025 tube plate by FWTPET process

Energy Technology Data Exchange (ETDEWEB)

Kannan, S., E-mail: kannan.dgl201127@gmail.com [Department of Mechanical Engineering and Mining Machinery Engineering, Indian Institute of Technology (ISM), Dhanbad, Jharkhand 826004 (India); Senthil Kumaran, S., E-mail: sskumaran@ymail.com [Research and Development Center, Department of Mechanical Engineering, RVS Educational Trust' s Group of Institutions, RVS School of Engineering and Technology, Dindigul, Tamilnadu 624005 (India); Kumaraswamidhas, L.A., E-mail: lakdhas1978@gmail.com [Department of Mechanical Engineering and Mining Machinery Engineering, Indian Institute of Technology (ISM), Dhanbad, Jharkhand 826004 (India)

2016-07-05

Frictional welding of tube to tube plate by external tool (FWTPET) posses wide spread industrial in mass production process for joint similar and dissimilar materials. Frictional welding process allows welding of some materials that are exceptionally hard to fusion weld. The good quality joint between the tube and tube plate is achieved by selecting the proper process parameter. In this present research, the frictional welding is done between the Aluminium 2025 tube plate and commercial copper tube possessing a clearance fit of 0.1 mm between tube and hole. In this study, two conditions were considered while handing out this experiment. The condiction1 is tube without holes [WOH] and condition 2 is tube with holes [WH] on the tube circumference. In total, twenty seven work pieces have been considered separately for both conditions and the mechanical property such as compression strength and hardness value has been measured for the both set of work piece in two conditions to analysis the joint strength of the welding process. Taguchi L{sub 27} orthogonal array has been used in this process to identify the process parameter which influences the joint strength of the welded samples. ANOVA method is used to calculate the percentage of contribution by each process parameter which influences the better joint strength. Genetic algorithm is used to authenticate the outcome obtained from the both experimental value and optimization value. Scanning Electron Microscope (SEM) and Energy-dispersive X-ray analysis (EDX) has been performed to probe microstructures and chemical compositions for work piece without holes which has higher mechanical property. - Highlights: • FWTPET for dissimilar metals commercial copper tube and Al 2025 tube plate. • The hardness value for tube without holes are 180.988 Hv. • The compression strength for tube without holes are 376.05 MPa. • SEM confirm heat production is done to melt parent metal by diffusion process. • EDX prove no trace

Internal heat exchange tubes for industrial furnaces

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, M.; Lingle, T.M.

1992-05-26

This patent describes a method for cooling the work within an industrial furnace. It comprises providing a longitudinally extending outer tube which extends into the furnace having a closed axial end and an open axial end; providing a preformed inner tube open at both ends within the outer tube; injecting a coolant into the inner tube so that the coolant flows from one axial end of the tube out the opposite end adjacent the closed end of the outer tube, and from the closed end of the outer tube to the open end thereof; circulating a gas within the furnace against the outer tube to effect heat transfer therewith.

Square through tube

International Nuclear Information System (INIS)

Akita, Junji; Honma, Toei.

1975-01-01

Object: To provide a square through tube involving thermal movement in pipelines such as water supply pump driving turbine exhaust pipe (square-shaped), which is wide in freedom with respect to shape and dimension thereof for efficient installation at site. Structure: In a through tube to be airtightly retained for purpose of decontamination in an atomic power plant, comprising a seal rubber plate, a band and a bolt and a nut for securing said plate, the seal rubber plate being worked into the desired shape so that it may be placed in intimate contact with the concrete floor surface by utilization of elasticity of rubber, thereby providing airtightness at a corner portion of the square tube. (Kamimura, M.)

Process and device for locating a defective tube, particularly in the tube bundle of a steam generator

International Nuclear Information System (INIS)

Denis, Jean.

1977-01-01

A process is described for locating a defective tube, particularly in the tube bundle of a steam generator of the reversed U tube kind with the ends connected to a tube plate, marking with the bottom of the generator casing a space separated into two adjacent collectors, respectively for the inlet and outlet of a primary fluid flowing inside the tubes of the bundle, these being externally washed by a secondary vaporizing fluid. In this process a television camera that can be inserted into the casing is used. This process consists in transmitting to a display system outside the generator an image of the tube plate in each collector by means of a directional television camera and then to place over this image a luminous marker to locate the end or the faulty tube [fr

Gastrostomy feeding tube - bolus

Science.gov (United States)

Feeding - gastrostomy tube - bolus; G-tube - bolus; Gastrostomy button - bolus; Bard Button - bolus; MIC-KEY - bolus ... KEY, 3 to 8 weeks after surgery. These feedings will help your child grow strong and healthy. ...

Feedwater heater tube-to-tubesheet connections

International Nuclear Information System (INIS)

Yokell, S.

1993-01-01

This paper discusses some practical aspects of expanded, welded, and welded-and-expanded feedwater heater tube-to-tubesheet joints. It outlines elastic-plastic tube expanding theory. It examines uniform-pressure-expanded tube joint strength and correlating roller-expanded joint strength with wall reduction and rolling torque. For materials subject to stress-corrosion cracking (SCC), it recommends heat treating tube ends before expanding. For materials subject to fatigue and tube-end cracking, it advocates two-stage expanding: (1) expanding enough to create firm tube-hole contact over the full tubesheet thickness; and (2) re-expanding at full pressure or torque. The paper emphasizes the desirability of segregating heats of tubing, mapping the tube-heat locations and making the heat map a permanent part of the heater maintenance file. It recommends when to provide TEMA/HEI Power Plant Standard annular grooves for roller-expanding and provides an equation for determining optimum groove width for uniform-pressure expanding. The paper also reviews welding requirements for welds of tubes to tubesheets. The review covers front-face welding before and after expanding and the reasons for welding first. It outlines current thinking about definitions of strength- and seal-welds of front-face welded joint in terms of their functions and load-carrying abilities. It presents a proposal for determining the required size of strength welds for use in Section VIII of the ASME Boiler and Pressure Vessel Code (the Code). It shows why welded-and-expanded feedwater heater tube-to-tubesheet joints should be full-strength and full-depth expanded. It makes recommendations for pressure- and leak-testing. This work also proposes the industry consider butt welding the tubes to the steam-side face of the tubesheet as a regular method of tube joining. The results of a survey of manufacturers practices are appended. 30 refs., 14 figs

Pressure loss characteristics of LSTF steam generator heat-transfer tubes. Pressure loss increase due to tube internal instruments

International Nuclear Information System (INIS)

Suzuki, Mitsuhiro

1994-11-01

The steam generator of the Large-Scale Test Facility (LSTF) includes 141 heat-transfer U-tubes with different lengths. Six U-tubes among them are furnished with 15 or 17 probe-type instruments (conduction probe with a thermocouple; CPT) protuberant into the primary side of the U-tubes. Other 135 U-tubes are not instrumented. This results in different hydraulic conditions between the instrumented and non-instrumented U-tubes with the same length. A series of pressure loss characteristics tests was conducted at a test apparatus simulating both types of U-tube. The following pressure loss coefficient (K CPT ) was reduced as a function of Reynolds number (Re) from these tests under single-phase water flow conditions. K CPT =0.16 5600≤Re≤52820, K CPT =60.66xRe -0.688 2420≤Re≤5600, K CPT =2.664x10 6 Re -2.06 1371≤Re≤2420. The maximum uncertainty is 22%. By using these results, the total pressure loss coefficients of full length U-tubes were estimated. It is clarified that the total pressure loss of the shortest instrumented U-tube is equivalent to that of the middle-length non-instrumented U-tube and also that a middle-length instrumented U-tube is equivalent to the longest non-instrumented U-tube. Concludingly. it is important to take account of the CPT pressure loss mentioned above in estimation of fluid behavior at the non-instrumented U-tubes either by using the LSTF experiment data from the CPT-installed U-tubes or by using any analytical codes. (author)

Otolaryngology Service Usage in Children With Cleft Palate.

Science.gov (United States)

Whittemore, Kenneth R; Dargie, Jenna M; Dornan, Briana K; Boudreau, Brian

2018-05-01

To determine the usage of otolaryngology services by children with cleft palate at a pediatric tertiary care facility. Retrospective case series. Specialty clinic at a pediatric tertiary care hospital. Children born between January 1, 1999, and December 31, 2002, with the diagnosis of cleft palate or cleft lip and palate. A total of 41 female and 48 male patients were included. Total number of otolaryngology clinic visits and total number of otolaryngologic surgeries (tympanostomy tube placements and other otologic or upper airway procedures). In the first 5 years of life, these children utilized an average of 8.2 otolaryngology clinic visits (SD = 5.0; range: 1-22) and underwent 3.3 tympanostomy tube surgeries (SD = 2.0; range: 0-10). Seventy-three had their first tube placed at the time of palate repair, and 4 at the time of lip repair. Fifty-one (57.3%) required other otologic or upper airway procedures, including tonsillectomy and/or adenoidectomy (27 children), removal of tympanostomy tubes (24 children), tympanomastoidectomy (3 children), and tympanoplasty (14 children). Of the children who underwent other procedures, they underwent a mean of 1.67 (SD = 0.84; range: 1-4) surgeries. Children with cleft palate are at increased risk for eustachian tube dysfunction, frequently utilize otolaryngology care, and typically receive multiple sets of tympanostomy tubes. This study found that children with cleft palate receive on average of approximately 3 sets of tympanostomy tubes, and the majority required another otologic or upper airway surgery.

Isolated Fallopian Tube Torsion in Adolescents

Directory of Open Access Journals (Sweden)

S. Rajaram

2013-01-01

Full Text Available Background. Fallopian tube torsion is a rare cause of acute abdomen, occurring commonly in females of reproductive age. It lacks pathognomonic symptoms, signs, or imaging features, thus causing delay in surgical intervention. Case. We report two cases of isolated fallopian tube torsion in adolescent girls. In the first case a 19-year-old patient presented with acute pain in the left iliac region associated with episodes of vomiting for one day and mild tenderness on examination. Laparoscopy revealed left sided twisted fallopian tube associated with hemorrhagic cyst of ovary. The tube was untwisted and salvaged. In another case an 18-year-old virgin girl presented with similar complaints since one week, associated with mild tenderness in the lower abdomen and tender cystic mass on per rectal examination. On laparoscopy right twisted fallopian tube associated with a paratubal cyst was found. Salpingectomy was done as the tube was gangrenous. Conclusion. Fallopian tube torsion, though rare, should be considered in women of reproductive age with unilateral pelvic pain. Early diagnostic laparoscopy is important for an accurate diagnosis and could salvage the tube.

Sleeving repair of heat exchanger tubes

International Nuclear Information System (INIS)

Street, Michael D.; Schafer, Bruce W.

2000-01-01

Defective heat exchanger tubes can be repaired using techniques that do not involve the cost and schedule penalties of component replacement. FTI's years of experience repairing steam generator tubes have been successfully applied to heat exchangers. Framatome Technologies heat exchanger sleeves can bridge defective areas of the heat exchanger tubes, sleeves have been designed to repair typical heat exchanger tube defects caused by excessive tube vibration, stress corrosion cracking, pitting or erosion. By installing a sleeve, the majority of the tube's heat transfer and flow capacity is maintained and the need to replace the heat exchanger can be delayed or eliminated. Both performance and reliability are improved. FTI typically installs heat exchanger tube sleeves using either a roll expansion or hydraulic expansion process. While roll expansion of a sleeve can be accomplished very quickly, hydraulic expansion allows sleeves to be installed deep within a tube where a roll expander cannot reach. Benefits of FTI's heat exchanger tube sleeving techniques include: - Sleeves can be positioned any where along the tube length, and for precise positioning of the sleeve eddy current techniques can be employed. - Varying sleeve lengths can be used. - Both the roll and hydraulic expansion processes are rapid and both produce joints that do not require stress relief. - Because of low leak rates and speed of installations, sleeves can be used to preventatively repair likely-to-fail tubes. - Sleeves can be used for tube stiffening and to limit leakage through tube defects. - Because of installation speed, there is minimal impact on outage schedules and budgets. FTI's recently installed heat exchanger sleeving at the Kori-3 Nuclear Power Station in conjunction with Korea Plant Service and Engineering Co., Ltd. The sleeves were installed in the 3A and 3B component cooling water heat exchangers. A total of 859 tubesheet and 68 freespan sleeves were installed in the 3A heat

Small size neutron tube UNG-1

International Nuclear Information System (INIS)

Bespalov, D.F.; Mints, A.Z.; Shkol'nikov, A.S.

A tube UNG-1 (universal neutron gas-filled) is designed for the use in the well neutron generators IGN-1 and IGN-1-M (a pulse neutron generator). Their serial production in the USSR has been started in 1963. At the same year, the serial production of the tubes UNG-1 has been started. Thus, this tube is the first serial logging accelerating tube in the USSR. A Penning source, equipped with a hot cathode, was selected as an ion source of the tube

Thru-tubing inflatable workover systems

International Nuclear Information System (INIS)

Coronado, M.P.; Mody, R.K.; Craig, G.C.

1991-01-01

Recent technological advances in inflatable packing element design has allowed non-conventional workover techniques to be accomplished through the production tubing. The improved capabilities of these elements, coupled with new tool designs allowing workovers to be completed with coiled tubing or electric wireline, has seen growing applications. These workovers include, selective and zonal chemical treatments, temporary and permanent plugback operations, intermediate zone blankoff, production and injection flow profile modifications and formation fracturing. They are completed without pulling the production tubing from the well, and thus do not require a rig on the well. Since these tools are snubbed in the well with coiled tubing or electric wireline, thus eliminating the need to kill the well, heavy weight kill fluids, which may cause formation damage, are not required. These tools have been designed to operate with hydraulic pressure and workstring tension within the coiled tubing limitations. This paper outlines the development of these Thru-tubing systems and application techniques that have been developed as a result of their field use. It discusses case histories of applications using this technology and the resulting increase in well performance. This paper also describes auxiliary equipment that has been developed to allow these tool systems to be used safely on coiled tubing and electric wireline

Tubing vs. buckets: a cost comparison

Science.gov (United States)

Neil K. Huyler

1975-01-01

Equipment investment for tubing-vacuum systems was significantly less than that for bucket systems. Tubing-vacuum systems required about 22 percent less labor input, the major labor input being completed before sap-flow periods. Annual cost of operation was less for tubing-vacuum than the bucket system. Small tubing-vacuum operations showed more profit potential than...

Small-bore chest tubes seem to perform better than larger tubes in treatment of spontaneous pneumothorax

DEFF Research Database (Denmark)

Iepsen, Ulrik Winning; Ringbæk, Thomas

2013-01-01

The aim of this study was to compare the efficacy and complications of surgical (large-bore) chest tube drainage with smaller and less invasive chest tubes in the treatment of non-traumatic pneumothorax (PT). ......The aim of this study was to compare the efficacy and complications of surgical (large-bore) chest tube drainage with smaller and less invasive chest tubes in the treatment of non-traumatic pneumothorax (PT). ...

Feeding tube insertion - gastrostomy

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/002937.htm Feeding tube insertion - gastrostomy To use the sharing features on this page, please enable JavaScript. A gastrostomy feeding tube insertion is the placement of a feeding ...

Precision heat forming of tetrafluoroethylene tubing

Science.gov (United States)

Ruiz, W. V.; Thatcher, C. S. (Inventor)

1981-01-01

An invention that provides a method of altering the size of tetrafluoroethylene tubing which is only available in limited combination of wall thicknesses and diameter are discussed. The method includes the steps of sliding the tetrafluoroethylene tubing onto an aluminum mandrel and clamping the ends of the tubing to the mandrel by means of clamps. The tetrafluorethylene tubing and mandrel are then placed in a supporting coil which with the mandrel and tetrafluorethylene tubing are then positioned in a insulated steel pipe which is normally covered with a fiber glass insulator to smooth out temperature distribution therein. The entire structure is then placed in an event which heats the tetrafluorethylene tubing which is then shrunk by the heat to the outer dimension of the aluminum mandrel. After cooling the aluminum mandrel is removed from the newly sized tetrafluorethylene tubing by a conventional chemical milling process.

Improving the calandria tubes for CANDU reactors

International Nuclear Information System (INIS)

Coleman, C.E.; Fong, R.W.L.; Doubt, G.L.

1997-01-01

CANDU calandria tubes are made from annealed Zircaloy-2 sheet formed into a cylinder and welded along its length to make the tube. The current calandria tubes have given exemplary service for many years. With more stringent regulations and the need to accommodate warm cooling water in tropical countries, we started a development program to increase the margins for failure during postulated accidents. These improvements involve increasing the tube strength and optimising the heat-transfer from an excessively hot fuel channel to the cool moderator. If the postulated accident involves a pressure tube break, it would be desirable if the calandria tube withstood the full pressure of the heat-transport system. The weakest link in current calandria tubes is the weld. Thickening the weld can increase the strength by 20% while seamless tubes can be 45% stronger than current tubes. The latter tubes can hold full system pressure for many hours without failure. If during the postulated accident the fuel and pressure tube become excessively hot but do not touch the calandria tube, the radiant heat loss must be maximised. Current calandria tubes have an absorptivity (emissivity) of about 0.2. To protect the fuel and the fuel channel we have devised a finish to the inside surface of the calandria tube that increases the emissivity to 0.7. If during the postulated accident the hot pressure tube touches the cool calandria tube, the contact conductance and the critical heat flux must be optimised to ensure nucleate boiling of the moderator at the outside surface of the calandria tube and therefore efficient exploitation of the moderator as a heat sink. In laboratory tests small ridges on the inside surface and roughening of the outside surface have been shown to increase the margins against failure and increase the possible moderator temperatures thus providing the opportunity to decrease the cost of the moderator heat-exchange system and remove restrictions on reactor operation in

Avoiding leakage flow-induced vibration by a tube-in-tube slip joint

International Nuclear Information System (INIS)

Mulcahy, T.M.

1985-01-01

Parameters and operating conditions (a stability map) were determined for which a specific slip-joint design did not cause self-excited lateral vibration of the two cantilevered, telescoping tubes forming the joint. The joint design featured a localized annular constriction. Flowrate, modal damping, tube engagement length, and eccentric positioning were among the parameters tested. Interestingly, all self-excited vibrations could be avoided by following a simple design rule: place constrictions only at the downstream end of the annular region between the tubes. Also, overall modal damping decreased with increased flowrate, at least initially, for upstream constrictions while the damping increased for downstream constrictions

Pyrotechnic Tubing Connector

Science.gov (United States)

Graves, Thomas J.; Yang, Robert A.

1988-01-01

Tool forms mechanical seal at joint without levers or hydraulic apparatus. Proposed tool intended for use in outer space used on Earth by heavily garbed workers to join tubing in difficult environments. Called Pyrotool, used with Lokring (or equivalent) fittings. Piston slides in cylinder when pushed by gas from detonating pyrotechnic charge. Impulse of piston compresses fittings, sealing around butting ends of tubes.

SG tube identification

International Nuclear Information System (INIS)

Hoogstraten, P. van

1994-01-01

A ''Tracker'' system is described which is designed to identify any tube in a reactor steam generator quickly and safely. Occupational radiation doses to maintenance workers are reduced by using a Tracker and emergency down times are shortened. The system employs a television camera and light source in a stainless steel box with a large window. Both the camera and spotlight can be panned and tilted to reach any point on the tubesheet and are remotely controlled. An operator at a safe working distance can identify any tube visible on a real time video by comparison with the tubesheet pattern stored earlier in the computer memory. The identified tube can then be spotlighted and dealt with quickly by a maintenance worker inside the channel head. (UK)

Numerical simulation of tubes-in-tube heat exchanger in a mixed refrigerant Joule-Thomson cryocooler

Science.gov (United States)

Damle, R. M.; Ardhapurkar, P. M.; Atrey, M. D.

2017-02-01

Mixed refrigerant Joule-Thomson (MRJT) cryocoolers can produce cryogenic temperatures with high efficiency and low operating pressures. As compared to the high system pressures of around 150-200 bar with nitrogen, the operational pressures with non-azeotropic mixtures (e.g., nitrogen-hydrocarbons) come down to 10-25 bar. With mixtures, the heat transfer in the recuperative heat exchanger takes place in the two-phase region. The simultaneous boiling and condensation of the cold and hot gas streams lead to higher heat transfer coefficients as compared to single phase heat exchange. The two-phase heat transfer in the recuperative heat exchanger drastically affects the performance of a MRJT cryocooler. In this work, a previously reported numerical model for a simple tube-in-tube heat exchanger is extended to a multi tubes-in-tube heat exchanger with a transient formulation. Additionally, the J-T expansion process is also considered to simulate the cooling process of the heat exchanger from ambient temperature conditions. A tubes-in-tube heat exchanger offers more heat transfer area per unit volume resulting in a compact design. Also, the division of flow in multiple tubes reduces the pressure drop in the heat exchanger. Simulations with different mixtures of nitrogen-hydrocarbons are carried out and the numerical results are compared with the experimental data.

Improper tube fixation causing a leaky cuff

Directory of Open Access Journals (Sweden)

Gupta Babita

2010-01-01

Full Text Available Leaking endotracheal tube cuffs are common problems in intensive care units. We report a case wherein the inflation tube was damaged by the adhesive plaster used for tube fixation and resulted in leaking endotracheal tube cuff. We also give some suggestions regarding the tube fixation and some remedial measures for damaged inflation system.

The Mashups of YouTube

DEFF Research Database (Denmark)

Simonsen, Thomas Mosebo

2013-01-01

This article focuses on YouTube mashups and how we can understand them as a specific subgenre on YouTube. The Mashups are analysed as audiovisual recontextualizations that are given new meaning, e.g., via collaborative social communities or for individual promotional purposes. This is elaborated......, but rather in its social and communicative abilities within the YouTube community. This leads to the article’s overall argument that the main characteristic of the YouTube Mashup can be explained in terms of connectivity. It is argued that Mashups reveal a double articulation of connectivity; one...... that involves the social mechanisms of the Mashups, and another mode, which concerns the explicit embedding of structural connectivity that accentuates the medium-specific infrastructure of YouTube. This double articulation of connectivity is furthermore elaborated on by including Grusin and Bolter’s concept...

100-ps framing-camera tube

International Nuclear Information System (INIS)

Kalibjian, R.

1978-01-01

The optoelectronic framing-camera tube described is capable of recording two-dimensional image frames with high spatial resolution in the <100-ps range. Framing is performed by streaking a two-dimensional electron image across narrow slits. The resulting dissected electron line images from the slits are restored into framed images by a restorer deflector operating synchronously with the dissector deflector. The number of framed images on the tube's viewing screen equals the number of dissecting slits in the tube. Performance has been demonstrated in a prototype tube by recording 135-ps-duration framed images of 2.5-mm patterns at the cathode. The limitation in the framing speed is in the external drivers for the deflectors and not in the tube design characteristics. Faster frame speeds in the <100-ps range can be obtained by use of faster deflection drivers

Když se řekne YouTube

OpenAIRE

Voců, Ondřej

2011-01-01

This article describes basic characteristics of YouTube portal, explains its importance and provided services. The first part of this article is applied to basic characteristics of YouTube portal, the second part deals with processes related to videos on YouTube. YouTube users, YouTube partners and projects are mainspring of the third part of this article. Special subchapter outlines possibilites of YouTube in relation to information studies and librarianship. At the end of the fourth chapter...

Water-storage-tube systems. Final report

Energy Technology Data Exchange (ETDEWEB)

Hemker, P.

1981-12-24

Passive solar collection/storage/distribution systems were surveyed, designed, fabricated, and mechanically and thermally tested. The types studied were clear and opaque fiberglass tubes, metal tubes with plastic liners, and thermosyphoning tubes. (MHR)

Preparation of metallic uranium tubes; Elaboration des tubes d'uranium metallique

Energy Technology Data Exchange (ETDEWEB)

Lerouge, G; Decours, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The production furnace is an induction heated vacuum furnace having a capacity at the moment of 250 kg. Previously the crucible was heated by the inductor, the mould being outside the inductor. The tubes thus produced contained cavities, the alloy structure was fine; this was cold-mould casting, At the moment the top of the moulds are pre-heated, this is the so called hot-mould casting. This method has the advantage of eliminating the cavities but leads to a less fine microstructure. The alloy used for the 18 x 40 mm and 23 x 43 mm tubes is U-Mo (1.1 per cent). Since the moulds are now heated at the top, the solidification of the metal is very slow in this zone leading to a pronounced {gamma} grain, whereas towards the base the faster cooling leads to a smaller {gamma} grain. The {gamma} structure depends essentially on the solidification rate and on the time spent in this zone. In order to obtain a fine and homogeneous grain along the whole length of the tube, a controlled cooling treatment is effected. It consists in heating the uranium tubes in the {gamma} place and then in cooling them at a rate of between 20 and 50 deg C/mm down to 400 deg C. The 77 x 95 mm and 54 x 70 mm annular elements are at the moment being produced for research purposes. Their preparation is similar to that of 18 x 40 mm and 23 x 43 mm elements. The 77 x 95 mm tubes are at the moment made from U-Cr alloy (0.1 per cent); because of their size, their preparation is carried out in 600 mm diameter furnaces. (authors) [French] Le four d'elaboration est un four sous vide chaufffe par induction, dont la capacite actuelle est de 250 kg. Anterieurement le creuset seul etait chauffe par l'inducteur, les moules etaient hors de l'inducteur. Les tubes obtenus presentaient des cavites, la structure de l'alliage etait fine, c'etait la coulee en moules froids. Actuellement on prechauffe le haut des moules, c'est la coulee dite en moules chauds. Cette facon de faire a l'avantage de supprimer les cavites

Gastroenteric tube feeding: Techniques, problems and solutions

Science.gov (United States)

Blumenstein, Irina; Shastri, Yogesh M; Stein, Jürgen

2014-01-01

Gastroenteric tube feeding plays a major role in the management of patients with poor voluntary intake, chronic neurological or mechanical dysphagia or gut dysfunction, and patients who are critically ill. However, despite the benefits and widespread use of enteral tube feeding, some patients experience complications. This review aims to discuss and compare current knowledge regarding the clinical application of enteral tube feeding, together with associated complications and special aspects. We conducted an extensive literature search on PubMed, Embase and Medline using index terms relating to enteral access, enteral feeding/nutrition, tube feeding, percutaneous endoscopic gastrostomy/jejunostomy, endoscopic nasoenteric tube, nasogastric tube, and refeeding syndrome. The literature showed common routes of enteral access to include nasoenteral tube, gastrostomy and jejunostomy, while complications fall into four major categories: mechanical, e.g., tube blockage or removal; gastrointestinal, e.g., diarrhea; infectious e.g., aspiration pneumonia, tube site infection; and metabolic, e.g., refeeding syndrome, hyperglycemia. Although the type and frequency of complications arising from tube feeding vary considerably according to the chosen access route, gastrointestinal complications are without doubt the most common. Complications associated with enteral tube feeding can be reduced by careful observance of guidelines, including those related to food composition, administration rate, portion size, food temperature and patient supervision. PMID:25024606

An advanced tube wear and fatigue workstation to predict flow induced vibrations of steam generator tubes

International Nuclear Information System (INIS)

Gay, N.; Baratte, C.; Flesch, B.

1997-01-01

Flow induced tube vibration damage is a major concern for designers and operators of nuclear power plant steam generators (SG). The operating flow-induced vibrational behaviour has to be estimated accurately to allow a precise evaluation of the new safety margins in order to optimize the maintenance policy. For this purpose, an industrial 'Tube Wear and Fatigue Workstation', called 'GEVIBUS Workstation' and based on an advanced methodology for predictive analysis of flow-induced vibration of tube bundles subject to cross-flow has been developed at Electricite de France. The GEVIBUS Workstation is an interactive processor linking modules as: thermalhydraulic computation, parametric finite element builder, interface between finite element model, thermalhydraulic code and vibratory response computations, refining modelling of fluid-elastic and random forces, linear and non-linear dynamic response and the coupled fluid-structure system, evaluation of tube damage due to fatigue and wear, graphical outputs. Two practical applications are also presented in the paper; the first simulation refers to an experimental set-up consisting of a straight tube bundle subject to water cross-flow, while the second one deals with an industrial configuration which has been observed in some operating steam generators i.e., top tube support plate degradation. In the first case the GEVIBUS predictions in terms of tube displacement time histories and phase planes have been found in very good agreement with experiment. In the second application the GEVIBUS computation showed that a tube with localized degradation is much more stable than a tube located in an extended degradation zone. Important conclusions are also drawn concerning maintenance. (author)

Tubing crimping pliers

Science.gov (United States)

Lindholm, G.T.

1981-02-27

The disclosure relates to pliers and more particularly to pliers for crimping two or more pieces of copper tubing together prior to their being permanently joined by brazing, soldering or the like. A die containing spring-loaded pins rotates within a cammed ring in the head of the pliers. As the die rotates, the pins force a crimp on tubing held within the pliers.

Tube Length and Water Flow

Directory of Open Access Journals (Sweden)

Ben Ruktantichoke

2011-06-01

Full Text Available In this study water flowed through a straight horizontal plastic tube placed at the bottom of a large tank of water. The effect of changing the length of tubing on the velocity of flow was investigated. It was found that the Hagen-Poiseuille Equation is valid when the effect of water entering the tube is accounted for.

Boiling heat transfer on horizontal tube bundles

International Nuclear Information System (INIS)

Anon.

1987-01-01

Nucleate boiling heat transfer characteristics for a tube in a bundle differ from that for a single tube in a pool and this difference is known as 'tube bundle effect.' There exist two bundle effects, positive and negative. The positive bundle effect enhances heat transfer due to convective flow induced by rising bubbles generated from the lower tubes, while the negative bundle effect deteriorates heat transfer due to vapor blanketing caused by accumulation of bubbles. Staggered tube bundles tested and found that the upper tubes in bundles have higher heat transfer coefficients than the lower tubes. The effects of various parameters such as pressure, tube geometry and oil contamination on heat transfer have been examined. Some workers attempted to clarify the mechanism of occurrence of 'bundle effect' by testing tube arrangements of small scale. All reported only enhancement in heat transfer but results showed the symptom of heat transfer deterioration at higher heat fluxes. As mentioned above, it has not been clarified so far even whether the 'tube bundle effect' should serve as enhancement or deterioration of heat transfer in nucleate boiling. In this study, experiments are performed in detail by using bundles of small scale, and effects of heat flux distribution, pressure and tube location are clarified. Furthermore, some consideration on the mechanisms of occurrence of 'tube bundle effect' is made and a method for prediction of heat transfer rate is proposed

N Reactor pressure tube 1350 postirradiation examination

International Nuclear Information System (INIS)

Cook, D.J.

1977-01-01

The N Reactor pressure tubes were fabricated from Zircaloy-2 primarily due to the excellent corrosion resistance, low neutron absorption, and high strength properties of this alloy. Irradiation damage mechanisms increase the strength and decrease the ductility of the Zircaloy-2. Irradiation data available at the time the tubes were installed indicated that fast neutron irradiation damage mechanisms would not decrease the ductility to unacceptable levels over the estimated plant life of 25 to 30 years. However, because the tubes are a primary coolant system component and only limited data are available on irradiation effects at high fluences, a Postirradiation Examination (PIE) program was developed to assure that service factors do not compromise pressure tube integrity essential to reactor safety. The PIE program requires that a pressure tube be periodically removed from the reactor for destructive testing. The N Reactor Technical Specifications specify that the frequency of pressure tube removal and examination be based upon the previous PIE test results. Four pressure tubes were examined before tube 1350, and the test results were summarized in individual reports. PIE results on tube 1350 were summarized along with the test results on the previous four tubes in a previous report. The purpose of this report is to present in detail the results on PIE of pressure tube 1350, and, in particular, document the technique by which the fracture toughness of the pressure tube was determined

Contrastive Analysis and Research on Negative Pressure Beam Tube System and Positive Pressure Beam Tube System for Mine Use

Science.gov (United States)

Wang, Xinyi; Shen, Jialong; Liu, Xinbo

2018-01-01

Against the technical defects of universally applicable beam tube monitoring system at present, such as air suction in the beam tube, line clogging, long sampling time, etc., the paper analyzes the current situation of the spontaneous combustion fire disaster forecast of mine in our country and these defects one by one. On this basis, the paper proposes a research thought that improving the positive pressure beam tube so as to substitute the negative pressure beam tube. Then, the paper introduces the beam tube monitoring system based on positive pressure technology through theoretical analysis and experiment. In the comparison with negative pressure beam tube, the paper concludes the advantage of the new system and draws the conclusion that the positive pressure beam tube is superior to the negative pressure beam tube system both in test result and test time. At last, the paper proposes prospect of the beam tube monitoring system based on positive pressure technology.

Leakproof Swaged Joints in Thin-Wall Tubing

Science.gov (United States)

Stuckenberg, F. H.; Crockett, L. K.; Snyder, W. E.

1986-01-01

Tubular inserts reinforce joints, reducing incidence of leaks. In new swaging technique, tubular inserts placed inside ends of both tubes to be joined. Made from thicker-wall tubing with outside diameter that matches inside diameter of thin tubing swaged, inserts support tube ends at joint. They ensure more uniform contact between swage fitting and tubing. New swaging technique developed for Al/Ti/V-alloy hydraulic supply lines.

Nasogastric tube versus gastrostomy tube for gastric decompression in abdominal surgery: a prospective, randomized trial comparing patients' tube-related inconvenience.

Science.gov (United States)

Hoffmann, S; Koller, M; Plaul, U; Stinner, B; Gerdes, B; Lorenz, W; Rothmund, M

2001-11-01

Perioperative decompression of the stomach is still a common procedure and can be achieved using either nasogastric tubes (NTs) or gastrostomy tubes (GTs). While both procedures appear to be equally effective, some authors believe that NTs are less convenient for patients than GTs. However, to date, no reliable prospective data are available on this issue. We conducted a prospective, randomized trial comparing NTs versus GTs with a total of 110 patients undergoing elective colon surgery. The primary outcome measure was the patient's tube-related inconvenience and pain, assessed in a standardized interview on day 2 after surgery and quantified by means of a visual-analog scale (VAS). A questionnaire including the EORTC QLQ-C30 and additional items regarding retrospective tube-related judgements was administered on the day of discharge and 4 weeks after discharge. Secondary endpoints were the therapy-related morbidity and general complications. When patients were asked which of their drainage tubes (all patients had three or four drainage tubes, such as decompression drains, urinary drains, central venous line) was most inconvenient, 43% (CI 33-53%) in the NT group reported that the NT was most inconvenient, while only 4% (CI 1-10%) of the GT patients judged the GT most inconvenient ( Ptube system (day 2 p.o.: 71%, CI 61-80%; 4 weeks p.o.: 66%, CI 56-75%) than did GT patients (day 2 p.o.: 94%, CI 88-98%; 4 weeks p.o.: 91% CI 84-96%); again, these differences were statistically significant ( Ptube system have to weigh up the possibilities of different averse clinical as well as subjective outcomes. It is then preferable to include patients' preferences in the individual decision making process (shared-decision making).

Numerical investigation of heat transfer in annulus laminar flow of multi tubes-in-tube helical coil

Science.gov (United States)

Nada, S. A.; Elattar, H. F.; Fouda, A.; Refaey, H. A.

2018-03-01

In the present study, a CFD analysis using ANSYS-FLUENT 14.5 CFD package is used to investigate the characteristics of heat transfer of laminar flow in annulus formed by multi tubes in tube helically coiled heat exchanger. The numerical results are validated by comparison with previous experimental data and fair agreements were existed. The influences of the design and operation parameters such as heat flux, Reynolds numbers and annulus geometry on the heat transfer characteristics are investigated. Different annulus of different numbers of inner tubes, specifically 1, 2, 3, 4 and 5 tubes, are tested. The Results showed that for all the studied annulus, the heat flux has no effect on the Nusselt number and compactness parameter. The annulus formed by using five inner tubes showed the best heat transfer performance and compactness parameter. Correlation of predicting Nusselt number in terms of Reynolds number and number of inner tubes are presented.

YouTube and ‘psychiatry’

Science.gov (United States)

Gordon, Robert; Miller, John; Collins, Noel

2015-01-01

YouTube is a video-sharing website that is increasingly used to share and disseminate health-related information, particularly among younger people. There are reports that social media sites, such as YouTube, are being used to communicate an anti-psychiatry message but this has never been confirmed in any published analysis of YouTube clip content. This descriptive study revealed that the representation of ‘psychiatry’ during summer 2012 was predominantly negative. A subsequent smaller re-analysis suggests that the negative portrayal of ‘psychiatry’ on YouTube is a stable phenomenon. The significance of this and how it could be addressed are discussed. PMID:26755987

Grooved tube plug rolls in

International Nuclear Information System (INIS)

Krausser, P.

1991-01-01

The removable plugs used to date by the Power Generation Group (KWU) of Siemens to seal defective steam generator tubes have a good track record. Their sealing principle is based on the elastic tensioning of three seal disks against the inside wall of the tube. Now a further removable plug is available -a roll-in plug with a metal-coated surface. It is particularly suitable for use in the roller-expanded zone of the tubes at the tube sheet. The plugs can be used in both Siemens-KWU steam generators and in steam generators manufactured in compliance with the guidelines of the ASME Code. (author)

Otoscopic diagnosis of otitis media.

Science.gov (United States)

Isaacson, Glenn

2016-12-01

Accurate diagnosis of otitis media is important to prevent suffering and complications when infection is present, and unnecessary antibiotic use when infection is absent. The usual signs and symptoms of acute otitis media are unreliable guides in infants and young children. Similarly, middle ear effusions may present with little discomfort in older children. We therefore depend on examination of the tympanic membrane with an otoscope to make most diagnoses. This article aims to improve the accuracy of middle ear diagnosis by pneumatic otoscopy. It includes descriptions and photographs of the normal ear drum and illustrates the pathologic changes seen in acute otitis media, long-standing eustachian tube dysfunction and otitis media with effusion.

Vibration characteristics of tubes in a heat exchanger

International Nuclear Information System (INIS)

Simonis; Steininger, D.

1985-01-01

Circumferential tube cracking has occurred in the once-through steam generators used in nuclear power plants. Analyses of failed tubes indicate that a fatigue process induced by tube vibration could cause the leaks. To investigate the vibration amplitude of tube spans during reactor operation, twenty-three tube spans were instrumented with accelerometers and strain gages at Three Mile Island Unit 2. To aid in the interpretation of the operational vibration measurements, tests were performed, in air, to determine the predominant resonant frequencies and mode shapes of selected tubes. By adapting modal analysis techniques, the two predominant response frequencies were determined for 100 randomly selected tube spans and the 23 instrumented tube spans; plus, the predominant mode shape was determined for five tube spans bounded by the tube sheet and the fifteenth support plate and one tube span bounded by the ninth and tenth support plate. The average value for the first and second predominant response frequency was 65 Hz and 170 Hz, respectively. The predominant frequencies for the individual tube spans are distributed randomly with no spatial orientation. The first predominant mode shape for the six tube spans tested corresponded to a classical beam with elastic supports. The equivalent stiffness of the elastic supports depend upon the tube span tested

Method of repairing pressure tube type reactors

International Nuclear Information System (INIS)

Asada, Takashi.

1983-01-01

Purpose: To enable to re-start the reactor operation in a short time, upon occurrence of failures in a pressure tube, as well as directly examine the cause for the failures in the pressure tube. Method: The pressure tube reactor main body comprises a calandria tank of a briquette form, pressure tubes, fuel assemblies and an iron-water shielding body. If failure is resulted to a pressure tube, the reactor operation is at first shutdown and nuclear fuel assemblies are extracted to withdraw from the pressure tube. Then, to an inlet pipe way and an outlet pipeway connected to the failed pressure tube, are attached plugs by means of welding or the like at the appropriate position where the radiation exposure dose is lower and the repairing work can be performed with ease. The pressure tube is disconnected to withdraw from the inlet pipeway and the outlet pipeway and, instead, radiation shielding plug tube is inserted and shield cooling device is actuated if required, wherein the reactor is actuated to re-start the operation. (Yoshino, Y.)

Practical acoustic thermometry with twin-tube and single-tube sensors

Energy Technology Data Exchange (ETDEWEB)

De Podesta, M.; Sutton, G.; Edwards, G.; Stanger, L.; Preece, H. [National Physical Laboratory, Teddington, (United Kingdom)

2015-07-01

Accurate measurement of high temperatures in a nuclear environment presents unique challenges. All secondary techniques inevitably drift because the thermometric materials in thermocouples and resistance sensors are sensitive not just to temperature, but also their own chemical and physical composition. The solution is to use primary methods that rely on fundamental links between measurable physical properties and temperature. In the nuclear field the best known technique is the measurement of Johnson Noise in a resistor (See Paper 80 at this conference). In this paper we describe the measurement of temperature in terms of the speed of sound in a gas confined in a tube - an acoustic waveguide. Acoustic thermometry is the most accurate technique of primary thermometry ever devised with the best uncertainty of measurement below 0.001 C. In contrast, the acoustic technique described in this work has a much larger uncertainty, approximately 1 deg. C. But the cost and ease of use are improved by several orders of magnitude, making implementation eminently practical. We first describe the basic construction and method of operation of thermometers using twin-tubes and single tubes. We then present results using a twin-tube design showing that showing long term stability (i.e. no detectable drift) at 700 deg. C over periods of several weeks. We then outline how the technique may be developed for different nuclear applications. (authors)

Ultra-fast framing camera tube

Science.gov (United States)

Kalibjian, Ralph

1981-01-01

An electronic framing camera tube features focal plane image dissection and synchronized restoration of the dissected electron line images to form two-dimensional framed images. Ultra-fast framing is performed by first streaking a two-dimensional electron image across a narrow slit, thereby dissecting the two-dimensional electron image into sequential electron line images. The dissected electron line images are then restored into a framed image by a restorer deflector operated synchronously with the dissector deflector. The number of framed images on the tube's viewing screen is equal to the number of dissecting slits in the tube. The distinguishing features of this ultra-fast framing camera tube are the focal plane dissecting slits, and the synchronously-operated restorer deflector which restores the dissected electron line images into a two-dimensional framed image. The framing camera tube can produce image frames having high spatial resolution of optical events in the sub-100 picosecond range.

High temperature ceramic-tubed reformer

Science.gov (United States)

Williams, Joseph J.; Rosenberg, Robert A.; McDonough, Lane J.

1990-03-01

The overall objective of the HiPHES project is to develop an advanced high-pressure heat exchanger for a convective steam/methane reformer. The HiPHES steam/methane reformer is a convective, shell and tube type, catalytic reactor. The use of ceramic tubes will allow reaction temperature higher than the current state-of-the-art outlet temperatures of about 1600 F using metal tubes. Higher reaction temperatures increase feedstock conversion to synthesis gas and reduce energy requirements compared to currently available radiant-box type reformers using metal tubes. Reforming of natural gas is the principal method used to produce synthesis gas (primarily hydrogen and carbon monoxide, H2 and CO) which is used to produce hydrogen (for refinery upgrading), methanol, as well as several other important materials. The HiPHES reformer development is an extension of Stone and Webster's efforts to develop a metal-tubed convective reformer integrated with a gas turbine cycle.

Physics of magnetic flux tubes

CERN Document Server

Ryutova, Margarita

2015-01-01

This book is the first account of the physics of magnetic flux tubes from their fundamental properties to collective phenomena in an ensembles of flux tubes. The physics of magnetic flux tubes is absolutely vital for understanding fundamental physical processes in the solar atmosphere shaped and governed by magnetic fields. High-resolution and high cadence observations from recent space and  ground-based instruments taken simultaneously at different heights and temperatures not only show the ubiquity of filamentary structure formation but also allow to study how various events are interconnected by system of magnetic flux tubes. The book covers both theory and observations. Theoretical models presented in analytical and phenomenological forms are tailored for practical applications. These are welded with state-of-the-art observations from early decisive ones to the most recent data that open a new phase-space for exploring the Sun and sun-like stars. Concept of magnetic flux tubes is central to various magn...

Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

International Nuclear Information System (INIS)

Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo; Min, Kyong Mahn

2013-01-01

In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG tubes

Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

Energy Technology Data Exchange (ETDEWEB)

Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo [Korea Hydro and Nuclear Power Co. Ltd, Daejeon (Korea, Republic of); Min, Kyong Mahn [Universal Monitoring and Inspection Inc., Daejeon (Korea, Republic of)

2013-10-15

In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG

Development, prevention, and treatment of feeding tube dependency.

Science.gov (United States)

Krom, Hilde; de Winter, J Peter; Kindermann, Angelika

2017-06-01

Enteral nutrition is effective in ensuring nutritional requirements and growth. However, when tube feeding lasts for a longer period, it can lead to tube dependency in the absence of medical reasons for continuation of tube feeding. Tube-dependent children are unable or refuse to start oral activities and they lack oral skills. Tube dependency has health-, psychosocial-, and economy-related consequences. Therefore, the transition to oral feeding is of great importance. However, this transition can be very difficult and needs a multidisciplinary approach. Most studies for treatment of tube dependency are based on behavioral interventions, such as family therapy, individual behavior therapy, neuro-linguistic programming, and parental anxiety reduction. Furthermore, oral motor therapy and nutritional adjustments can be helpful in tube weaning. The use of medication has been described in the literature. Although mostly chosen as the last resort, hunger-inducing methods, such as the Graz-model and the Dutch clinical hunger provocation program, are also successful in weaning children off tube feeding. The transition from tube to oral feeding is important in tube-dependent children but can be difficult. We present an overview for the prevention and treatment of tube dependency. What is known: • Longer periods of tube feeding can lead to tube dependency. • Tube weaning can be very difficult. What is new: • Weaning as soon as possible and therefore referral to a multidisciplinary team are recommended. • An overview of treatment options for tube dependency is presented in this article.

Flaming on YouTube

NARCIS (Netherlands)

Moor, Peter J.; Heuvelman, A.; Verleur, R.

2010-01-01

In this explorative study, flaming on YouTube was studied using surveys of YouTube users. Flaming is defined as displaying hostility by insulting, swearing or using otherwise offensive language. Three general conclusions were drawn. First, although many users said that they themselves do not flame,

CFD modeling of a boiler's tubes rupture

International Nuclear Information System (INIS)

Rahimi, Masoud; Khoshhal, Abbas; Shariati, Seyed Mehdi

2006-01-01

This paper reports the results of a study on the reason for tubes damage in the superheater Platen section of the 320 MW Bisotoun power plant, Iran. The boiler has three types of superheater tubes and the damage occurs in a series of elbows belongs to the long tubes. A three-dimensional modeling was performed using an in-house computational fluid dynamics (CFD) code in order to explore the reason. The code has ability of simultaneous solving of the continuity, the Reynolds-Averaged Navier-Stokes (RANS) equations and employing the turbulence, combustion and radiation models. The whole boiler including; walls, burners, air channels, three types of tubes, etc., was modeled in the real scale. The boiler was meshed into almost 2,000,000 tetrahedral control volumes and the standard k-ε turbulence model and the Rosseland radiation model were used in the model. The theoretical results showed that the inlet 18.9 MPa saturated steam becomes superheated inside the tubes and exit at a pressure of 17.8 MPa. The predicted results showed that the temperature of the steam and tube's wall in the long tubes is higher than the short and medium size tubes. In addition, the predicted steam mass flow rate in the long tube was lower than other ones. Therefore, it was concluded that the main reason for the rupture in the long tubes elbow is changing of the tube's metal microstructure due to working in a temperature higher than the design temperature. In addition, the structural fatigue tension makes the last elbow of the long tube more ready for rupture in comparison with the other places. The concluded result was validated by observations from the photomicrograph of the tube's metal samples taken from the damaged and undamaged sections

Flow-induced decentering and tube support interaction for steam generator tubes: experiment and physical interpretation

International Nuclear Information System (INIS)

Gay, N.; Granger, S.

1992-11-01

Maintaining PWR components under reliable operating conditions requires a complex design to prevent various damaging processes including flow-induced vibration and wear mechanisms. To improve the prediction of tube/support interaction and wear in PWR components, EDF has undertaken a comprehensive program oriented to both experimental and computational studies. The present paper illustrates one aspect of this program, related to the determination of contact forces between steam generator tubes and anti-vibration bars (AVBs). The dynamic, nonlinear behavior of a U-tube excited by an air cross-flow is investigated on the CLAVECIN experiment. Interesting and rather unexpected results have been obtained, by varying clearances and flow velocities. The paper is focused on four main points: (i) the originality of the experiment with a force measurement device located in flow; (ii) the importance of a refined data processing for accurately measuring contact forces; (iii) the presentation of the unexpected phenomena revealed in the CLAVECIN experiment, i.e. a flow-induced decentering of the tube which changed the initial tube/AVB clearance, and the consequences on tube/support interaction; (iv) the influence of the actual tube/support clearance in flow on wear mechanisms. The work, presented in the second part of this paper, concentrates exclusively on the physical interpretation of the flow-induced decentering phenomenon and on the theoretical analysis of its consequences on dynamic tube/support interaction. We show that the flow-induced decentering phenomenon can be generated by an unstable quasi-static coupling between the flexible tube and the confined flow, in the vicinity of the support system. This phenomenon is not specific to the CLAVECIN tests and it can be expected every time that a movable obstacle is subjected to confined flow. Moreover, in single-sided impacting conditions, the theoretical analysis confirms the linear relation, found in the CLAVECIN tests

Models for Automated Tube Performance Calculations

International Nuclear Information System (INIS)

Brunkhorst, C.

2002-01-01

High power radio-frequency systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance

PROBLEMS IN THE TUBING/PACKER SYSTEM

OpenAIRE

Davorin Matanović; Mario Livaja

1993-01-01

When gas and oil wells are completed and produced or treated through the tubing connected to packer, there is a great number of problems to be solved. Changes in temperatures and pressures that occure during various operations ussually result in changes in tubing lengths or tubing to packer forces, depending on tubing to packer connections. This paper summarises some earlier papers and explains partly elaborated details. It also gives a complete approach to solve problems in uniform strings r...

Operating performance of CANDU pressure tubes

International Nuclear Information System (INIS)

Cheadle, B.A.; Price, E.G.

1989-04-01

The performance of Zircaloy-2 and Zr-2.5 Nb pressure tubes in CANDU reactors is reviewed. The accelerated hydriding of Zircaloy-2 in reducing water chemistries can lower the toughness of this material and it is essential that defect-initiating phenomena, such as hydride blister formation from pressure tube to calandria tube contact, be prevented. Zr-2.5 Nb pressure tubes are performing well with low rates of hydrogen pick-up and good retention of material properties

Dynamics of explosively imploded pressurized tubes

Science.gov (United States)

Szirti, Daniel; Loiseau, Jason; Higgins, Andrew; Tanguay, Vincent

2011-04-01

The detonation of an explosive layer surrounding a pressurized thin-walled tube causes the formation of a virtual piston that drives a precursor shock wave ahead of the detonation, generating very high temperatures and pressures in the gas contained within the tube. Such a device can be used as the driver for a high energy density shock tube or hypervelocity gas gun. The dynamics of the precursor shock wave were investigated for different tube sizes and initial fill pressures. Shock velocity and standoff distance were found to decrease with increasing fill pressure, mainly due to radial expansion of the tube. Adding a tamper can reduce this effect, but may increase jetting. A simple analytical model based on acoustic wave interactions was developed to calculate pump tube expansion and the resulting effect on the shock velocity and standoff distance. Results from this model agree quite well with experimental data.

Influence of tube spinning on formability of friction stir welded aluminum alloy tubes for hydroforming application

Energy Technology Data Exchange (ETDEWEB)

Wang, X.S. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Hu, Z.L., E-mail: zhilihuhit@163.com [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Hubei Key Laboratory of Advanced Technology of Automobile Parts, Wuhan University of Technology, Wuhan 430070 (China); State Key Laboratory of Materials Processing and Die and Mould Technology, Huazhong University of Science and Technology (China); Yuan, S.J. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Hua, L. [Hubei Key Laboratory of Advanced Technology of Automobile Parts, Wuhan University of Technology, Wuhan 430070 (China)

2014-06-01

Due to economic and ecological reasons, the application of tailor-welded blanks of aluminum alloy has gained more and more attention in manufacturing lightweight structures for automotives and aircrafts. In the study, the research was aimed to highlight the influence of spinning on the formability of FSW tubes. The microstructural characteristics of the FSW tubes during spinning were studied by electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The formability of the FSW tubes with different spinning reduction was assessed by hydraulic bulge test. It is found that the spinning process shows a grain refinement of the tube. The grains of the FSW tube decrease with increasing thickness reduction, and the effect of grain refinement is more obvious for the BM compared to that of the weld. The difference of grain size and precipitates between the weld and BM leads to an asymmetric W-type microhardness distribution after spinning. The higher thickness reduction of the tube, the more uniform distribution of grains and precipitates it shows, and consequently results in more significant increase of strength. As compared with the result of tensile test, the tube after spinning shows better formability when the stress state changes from uniaxial to biaxial stress state.

Tube vibration in industrial size test heat exchanger

International Nuclear Information System (INIS)

Halle, H.; Wambsganss, M.W.

1980-03-01

Tube vibration data from tests of a specially built and instrumented, industrial-type, shell-and-tube heat exchanger are reported. The heat exchanger is nominally 0.6 m (2 ft) in dia and 3.7 m (12 ft) long. Both full tube and no-tubes-in-window bundles were tested for inlet/outlet nozzles of different sizes and with the tubes supported by seven, equally-spaced, single-segmental baffles. Prior to water flow testing, natural frequencies and damping of representative tubes were measured in air and water. Flow testing was accomplished by increasing the flow rates in stepwise fashion and also by sweeping through a selected range of flow rates. The primary variables measured and reported are tube accelerations and/or displacements and pressure drop through the bundle. Tests of the full tube bundle configuration revealed tube rattling to occur at intermediate flow rates, and fluidelastic instability, with resultant tube impacting, to occur when the flow rate exceeded a threshold level; principally, the four-span tubes were involved in the regions immediately adjacent to the baffle cut. For the range of flow rates tested, fluidelastic instability was not achieved in the no-tubes-in-window bundle; in this configuration the tubes are supported by all seven baffles and are, therefore, stiffer

Numerical simulation of pulse-tube refrigerators

NARCIS (Netherlands)

Lyulina, I.A.; Mattheij, R.M.M.; Tijsseling, A.S.; Waele, de A.T.A.M.

2004-01-01

A new numerical model has been introduced to study steady oscillatory heat and mass transfer in the tube section of a pulse-tube refrigerator. Conservation equations describing compressible gas flow in the tube are solved numerically, using high resolution schemes. The equation of conservation of

Stop Smoking—Tube-In-Tube Helical System for Flameless Calcination of Minerals

Directory of Open Access Journals (Sweden)

Nils Haneklaus

2017-11-01

Full Text Available Mineral calcination worldwide accounts for some 5–10% of all anthropogenic carbon dioxide (CO2 emissions per year. Roughly half of the CO2 released results from burning fossil fuels for heat generation, while the other half is a product of the calcination reaction itself. Traditionally, the fuel combustion process and the calcination reaction take place together to enhance heat transfer. Systems have been proposed that separate fuel combustion and calcination to allow for the sequestration of pure CO2 from the calcination reaction for later storage/use and capture of the combustion gases. This work presents a new tube-in-tube helical system for the calcination of minerals that can use different heat transfer fluids (HTFs, employed or foreseen in concentrated solar power (CSP plants. The system is labeled ‘flameless’ since the HTF can be heated by other means than burning fossil fuels. If CSP or high-temperature nuclear reactors are used, direct CO2 emissions can be divided in half. The technical feasibility of the system has been accessed with a brief parametric study here. The results suggest that the introduced system is technically feasible given the parameters (total heat transfer coefficients, mass- and volume flows, outer tube friction factors, and –Nusselt numbers that are examined. Further experimental work will be required to better understand the performance of the tube-in-tube helical system for the flameless calcination of minerals.

Tube Thoracostomy: Complications and Its Management

Directory of Open Access Journals (Sweden)

Emeka B. Kesieme

2012-01-01

Full Text Available Background. Tube thoracostomy is widely used throughout the medical, surgical, and critical care specialities. It is generally used to drain pleural collections either as elective or emergency. Complications resulting from tube thoracostomy can occasionally be life threatening. Aim. To present an update on the complications and management of complications of tube thoracostomy. Methods. A review of the publications obtained from Medline search, medical libraries, and Google on tube thoracostomy and its complications was done. Results. Tube thoracostomy is a common surgical procedure which can be performed by either the blunt dissection technique or the trocar technique. Complication rates are increased by the trocar technique. These complications have been broadly classified as either technical or infective. Technical causes include tube malposition, blocked drain, chest drain dislodgement, reexpansion pulmonary edema, subcutaneous emphysema, nerve injuries, cardiac and vascular injuries, oesophageal injuries, residual/postextubation pneumothorax, fistulae, tumor recurrence at insertion site, herniation through the site of thoracostomy, chylothorax, and cardiac dysrhythmias. Infective complications include empyema and surgical site infection. Conclusion. Tube thoracostomy, though commonly performed is not without risk. Blunt dissection technique has lower risk of complications and is hence recommended.

Tube Thoracostomy: Complications and Its Management

Science.gov (United States)

Kesieme, Emeka B.; Dongo, Andrew; Ezemba, Ndubueze; Irekpita, Eshiobo; Jebbin, Nze; Kesieme, Chinenye

2012-01-01

Background. Tube thoracostomy is widely used throughout the medical, surgical, and critical care specialities. It is generally used to drain pleural collections either as elective or emergency. Complications resulting from tube thoracostomy can occasionally be life threatening. Aim. To present an update on the complications and management of complications of tube thoracostomy. Methods. A review of the publications obtained from Medline search, medical libraries, and Google on tube thoracostomy and its complications was done. Results. Tube thoracostomy is a common surgical procedure which can be performed by either the blunt dissection technique or the trocar technique. Complication rates are increased by the trocar technique. These complications have been broadly classified as either technical or infective. Technical causes include tube malposition, blocked drain, chest drain dislodgement, reexpansion pulmonary edema, subcutaneous emphysema, nerve injuries, cardiac and vascular injuries, oesophageal injuries, residual/postextubation pneumothorax, fistulae, tumor recurrence at insertion site, herniation through the site of thoracostomy, chylothorax, and cardiac dysrhythmias. Infective complications include empyema and surgical site infection. Conclusion. Tube thoracostomy, though commonly performed is not without risk. Blunt dissection technique has lower risk of complications and is hence recommended. PMID:22028963

Bradycardia after Tube Thoracostomy for Spontaneous Pneumothorax

Directory of Open Access Journals (Sweden)

Yomi Fashola

2018-01-01

Full Text Available We present the case of an elderly patient who became bradycardic after chest tube insertion for spontaneous pneumothorax. Arrhythmia is a rare complication of tube thoracostomy. Unlike other reported cases of chest tube induced arrhythmias, the bradycardia in our patient responded to resuscitative measures without removal or repositioning of the tube. Our patient, who had COPD, presented with shortness of breath due to spontaneous pneumothorax. Moments after tube insertion, patient developed severe bradycardia that responded to Atropine. In patients requiring chest tube insertion, it is important to be prepared to provide cardiopulmonary resuscitative therapy in case the patient develops a life-threatening arrhythmia.

A comparative Thermal Analysis of conventional parabolic receiver tube and Cavity model tube in a Solar Parabolic Concentrator

Science.gov (United States)

Arumugam, S.; Ramakrishna, P.; Sangavi, S.

2018-02-01

Improvements in heating technology with solar energy is gaining focus, especially solar parabolic collectors. Solar heating in conventional parabolic collectors is done with the help of radiation concentration on receiver tubes. Conventional receiver tubes are open to atmosphere and loose heat by ambient air currents. In order to reduce the convection losses and also to improve the aperture area, we designed a tube with cavity. This study is a comparative performance behaviour of conventional tube and cavity model tube. The performance formulae were derived for the cavity model based on conventional model. Reduction in overall heat loss coefficient was observed for cavity model, though collector heat removal factor and collector efficiency were nearly same for both models. Improvement in efficiency was also observed in the cavity model’s performance. The approach towards the design of a cavity model tube as the receiver tube in solar parabolic collectors gave improved results and proved as a good consideration.

Elastic-plastic analysis of tube expansion in tubesheets

International Nuclear Information System (INIS)

Kasraie, B.; O'Donnell, W.J.; Porowski, J.S.; Selz, A.

1983-01-01

Conditions for expansion of tubes in tubesheets are often determined by the test. The tightness of the joint and pull out force are used as criteria for evaluation of the results. For closely spaced tubes, it is also necessary to control development of the plastic regions in the ligaments surrounding the tube being expanded. High local strains may occur and excessive distortion may result if the expansion of the tube is continued beyond the admissible limits. Elastic-plastic finite element analyses are performed herein in order to establish conditions for rolling of the tubes in tubesheets of low ligament efficiency. Such penetration patterns are often required in the design of tubular reactors for catalytic processes. The model considered includes individual tube expansion in tubesheets with triangular penetration patterns. The effect of prior expansion of the neighboring tubes is also evaluated. Gap elements are used to model the initial clearance of the tube in the hole. Development of the plastic zones and distortion of the ligaments is monitored during radial expansion of the tube diameter. The residual stresses between the tube and the hole surface and the history of gap closing after removal of the expansion tool are determined. The effect of axial extension of the tube on the tube thinning is determined. Tube thinning is often used as a measure of tube expansion in manufacturing processes. For the analyzed ligament efficiency, reliable joints are obtained for a thinning range within 2% to 3%

Tube bundle vibrations in transversal flow

International Nuclear Information System (INIS)

Gibert, R.J.; Sagner, M.

1978-01-01

This study gives important information concerning characteristic parameters about lock-in and whirling instability phenomena, in the case of tube arrays. The work is mainly an experimental one though models are also developed: 1) an equilateral pitch bundle (p=1,5 D with D=tube diameter) is tested. Tube damping (epsilon) and first eigenfrequency (f), flow velocity are explored in a large domain. Vibratory level of the tubes are measured and critical points are ploted on the fluidelastic parameters diagram. Several bundles with various usual pitches and arrangements (in line or staggered) are tested. Critical velocities are measured and the whirling instability characteristic coefficient is tabulated. A complementary experiment is made on tube rows with various pitches. This gives valuable informations concerning the look-in domain in VR and A'R diagram. Furthermore this puts in evidence the important effect of a frequency difference between two adjacent tubes on the whirling critical velocity

21 CFR 888.4230 - Cement ventilation tube.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement ventilation tube. 888.4230 Section 888.4230...) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4230 Cement ventilation tube. (a) Identification. A cement ventilation tube is a tube-like device usually made of plastic intended to be inserted into...

Analysis of forming limit in tube hydroforming

International Nuclear Information System (INIS)

Kim, Chan Il; Yang, Seung Hang; Kim, Young Suk

2013-01-01

The automotive industry has shown increasing interest in tube hydroforming. Despite many automobile structural parts being produced from cylindrical tubes, failures frequently occur during tube hydroforming under improper forming conditions. These problems include wrinkling, buckling, folding back, and bursting. We perform analytical studies to determine forming limits in tube hydroforming and demonstrate how these forming limits are influenced by the loading path. Theoretical results for the forming limits of wrinkling and bursting are compared with experimental results for an aluminum tube.

Integrating YouTube into the nursing curriculum.

Science.gov (United States)

Sharoff, Leighsa

2011-08-17

Nurse educators need to be innovative, stimulating, and engaging as they teach future nursing professionals. The use of YouTube in nursing education classes provides an easy, innovative, and user-friendly way to engage today's nursing students. YouTube presentations can be easily adapted into nursing courses at any level, be it a fundamentals course for undergraduate students or a theoretical foundations course for graduate students. In this article I will provide information to help educators effectively integrate YouTube into their course offerings. I will start by reviewing the phenomenon of social networking. Next I will discuss challenges and strategies related to YouTube learning experiences, after which I will share some of the legal considerations in using YouTube. I will conclude by describing how to engage students via YouTube and current research related to YouTube.

Tests of compressed geometry NEC acceleration tubes

International Nuclear Information System (INIS)

Raatz, J.E.; Rathmell, R.D.; Stelson, P.H.; Ziegler, N.F.

1985-01-01

Tests have been performed in the 3 MV Pelletron test machine at NEC on a compressed geometry tube which increases the insulating length of the tube by eliminating the heated electrode assemblies (approx.2.5 cm thick) at the end of each tube section. Some insert electrodes are changed to provide some trapping of secondary ions. The geometry tested provided an 18% increase in live ceramic in the tube. The compressed geometry tube allowed a terminal voltage of 3.55 MV on the 3 MV column at normal gradients of 30.3 kv/tube gap. The tube was also conditioned to more than 4 MV and remained stable in voltage with few sparks and with low x-ray levels for days at about 4 MV. This same performance could be achieved with or without arc discharge cleaning. 4 refs., 4 figs

Tensile properties of quadruple melted Zr-2.5Nb pressure tubes evaluated from pressure tube offcuts

International Nuclear Information System (INIS)

Shah, Priti Kotak; Dubey, J.S.; Anantharaman, S.

2013-12-01

Rajasthan Atomic Power Station-2 (RAPS-2) is the first Pressurised Heavy Water Reactor (PHWR) in India having quadruple melted Zr-2.5Nb pressure tubes. Front-end and back-end off-cuts of sixteen pressure tubes were selected for studying the mechanical properties in axial and transverse directions of the tube. Tension tests were carried out at room temperature and at 300℃ using miniature tensile test specimens. The report presents the experimental details and discusses the base line tensile property data for the quadruple melted pressure tubes of RAPS-2. This data will be useful for the reactor life management. (author)

Caring for Your Percutaneous Nephrostomy Tube

Science.gov (United States)

... to the nephrostomy tube for 15 seconds. 5. Disconnect the drainage bag from the tube. 6. Put the used bag aside. 7. With a new alcohol pad, swab the open end of the nephrostomy tube for 15 seconds. 8. Connect a new bag. 9. Secure the drainage bag ...

The Fuge Tube Diode Array Spectrophotometer

Science.gov (United States)

Arneson, B. T.; Long, S. R.; Stewart, K. K.; Lagowski, J. J.

2008-01-01

We present the details for adapting a diode array UV-vis spectrophotometer to incorporate the use of polypropylene microcentrifuge tubes--fuge tubes--as cuvettes. Optical data are presented validating that the polyethylene fuge tubes are equivalent to the standard square cross section polystyrene or glass cuvettes generally used in…

21 CFR 872.6570 - Impression tube.

Science.gov (United States)

2010-04-01

... DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6570 Impression tube. (a) Identification. An impression tube is a device consisting of a hollow copper tube intended to take an impression of a single tooth...) Classification. Class I (general controls). The device is exempt from the premarket notification procedures in...

Preparation of metallic uranium tubes; Elaboration des tubes d'uranium metallique

Energy Technology Data Exchange (ETDEWEB)

Lerouge, G.; Decours, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The production furnace is an induction heated vacuum furnace having a capacity at the moment of 250 kg. Previously the crucible was heated by the inductor, the mould being outside the inductor. The tubes thus produced contained cavities, the alloy structure was fine; this was cold-mould casting, At the moment the top of the moulds are pre-heated, this is the so called hot-mould casting. This method has the advantage of eliminating the cavities but leads to a less fine microstructure. The alloy used for the 18 x 40 mm and 23 x 43 mm tubes is U-Mo (1.1 per cent). Since the moulds are now heated at the top, the solidification of the metal is very slow in this zone leading to a pronounced {gamma} grain, whereas towards the base the faster cooling leads to a smaller {gamma} grain. The {gamma} structure depends essentially on the solidification rate and on the time spent in this zone. In order to obtain a fine and homogeneous grain along the whole length of the tube, a controlled cooling treatment is effected. It consists in heating the uranium tubes in the {gamma} place and then in cooling them at a rate of between 20 and 50 deg C/mm down to 400 deg C. The 77 x 95 mm and 54 x 70 mm annular elements are at the moment being produced for research purposes. Their preparation is similar to that of 18 x 40 mm and 23 x 43 mm elements. The 77 x 95 mm tubes are at the moment made from U-Cr alloy (0.1 per cent); because of their size, their preparation is carried out in 600 mm diameter furnaces. (authors) [French] Le four d'elaboration est un four sous vide chaufffe par induction, dont la capacite actuelle est de 250 kg. Anterieurement le creuset seul etait chauffe par l'inducteur, les moules etaient hors de l'inducteur. Les tubes obtenus presentaient des cavites, la structure de l'alliage etait fine, c'etait la coulee en moules froids. Actuellement on prechauffe le haut des moules, c'est la coulee dite en moules chauds. Cette facon de faire a l

Researching YouTube

OpenAIRE

Arthurs, Jane; Drakopoulou, Sophia; Gandini, Alessandro

2018-01-01

‘Researching YouTube’ introduces the special issue of Convergence which arose out of an international academic conference on YouTube that was held in London at Middlesex University in September 2016. The conference aimed to generate a robust overview of YouTube’s changing character and significance after its first ten years of development by creating a productive dialogue between speakers from different disciplines and cultures, and between YouTube-specific research and wider debates in media...

Contribution to the heat transfer analysis of substitute refrigerants in evaporator tubes with smooth or enhanced tube surfaces

Energy Technology Data Exchange (ETDEWEB)

Kattan, N

1997-12-31

The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requests a good knowledge of heat transfer properties of substitute fluids. A new test facility has been built at the Laboratory for Industrial Energy Systems (LENI) to contribute to this international effort. It consists of two sets of concentric tubes allowing either annular or inside tube convective boiling with a counter current water flow heating to be studied. A new data base including heat transfer coefficients and pressure drop measurements for four new refrigerants (R123, R134A, R402A and R404A) and three older refrigerants (R11, R12 and R502) has been collected. Flow boiling measurements covered a broad range of mass velocities, vapor qualities and heat fluxes. Some of the tests included plain tubes and others enhanced surface tubes (microfilms from Wieland) in horizontal and vertical orientations. An improved Wilson plot technique, that covers both the transition and turbulent flow regimes of the water flowing in the annular channel for the inside tube boiling tests, is proposed to overcome the severe limitations of conventional Wilson plots, to improve accuracy and to facilitate data processing. Mean flow boiling heat transfer coefficients were measured for R12 and R134A evaporating inside a horizontal plain tube and for R11 and R123 evaporating inside a horizontal plain tube. Local flow boiling heat transfer coefficients were measured for : R134A, R123, R404A and R502 evaporating inside a horizontal plain tube, for R134A and R123 evaporating inside a horizontal microfin tube and for R134 evaporating inside a vertical microfin tube. In addition microfin heat transfer augmentation relative to plain tube test data was investigated. The measured heat transfer coefficients were compared to different existing inside tube flow boiling correlations. (author) figs., tabs., refs.

Measurements of electrically exploded tubes

International Nuclear Information System (INIS)

Shearer, J.W.; Hartman, C.W.; Munger, R.H.; Gullickson, R.L.; Trimble, D.O.; Cheng, D.Y.

1975-01-01

The dynamics of electrically exploded tubes were investigated, principally by means of current measurements and flash x-ray pictures. The pinch effect was observed on the tube motion. Pileup of the imploding tube metal was seen on axis. An approximate analytical model can be roughly fitted to the data, but a more complete fit can be obtained with detailed numerical codes. Application of the results to the planning of future gas-embedded Z-pinch experiments is discussed. (U.S.)

Photomultiplier tubes for Low Level Cerenkov Detectors

Energy Technology Data Exchange (ETDEWEB)

Strindehag, O

1965-03-15

Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a {beta}-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10{sup -12} input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10{sup -12} to 10{sup -9} input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses.

Confined Tube Crimp Using Portable Hand Tools

Energy Technology Data Exchange (ETDEWEB)

Reynolds, Joseph James [Los Alamos National Laboratory; Pereyra, R. A. [LANL Retired; Archuleta, Jeffrey Christopher [Los Alamos National Laboratory; Martinez, Isaac P. [Los Alamos National Laboratory; Nelson, A. M. [MST-16 Summer Student (2007); Allen, Ronald Scott [Los Alamos National Laboratory; Page, R. L. [LANL Retired; Freer, Jerry Eugene [Los Alamos National Laboratory; Dozhier, Nathan Gus [Los Alamos National Laboratory

2016-04-04

The Lawrence Radiation Laboratory developed handheld tools that crimp a 1/16 inch OD tube, forming a leak tight seal1 (see Figure 1). The leak tight seal forms by confining the 1/16 inch OD tubing inside a die while applying crimp pressure. Under confined pressure, the tube walls weld at the crimp. The purpose of this study was to determine conditions for fabricating a leak tight tube weld. The equipment was used on a trial-and-error basis, changing the conditions after each attempt until successful welds were fabricated. To better confine the tube, the die faces were polished. Polishing removed a few thousandths of an inch from the die face, resulting in a tighter grip on the tubing wall. Using detergent in an ultrasonic bath, the tubing was cleaned. Also, the time under crimp pressure was increased to 30 seconds. With these modifications, acceptable cold welds were fabricated. After setting the conditions for an acceptable cold weld, the tube was TIG welded across the crimped face.

Photomultiplier tubes for Low Level Cerenkov Detectors

International Nuclear Information System (INIS)

Strindehag, O.

1965-03-01

Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a β-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10 -12 input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10 -12 to 10 -9 input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses

Ion Implantation Hampers Pollen Tube Growth and Disrupts Actin Cytoskeleton Organization in Pollen Tubes of Pinus thunbergii

International Nuclear Information System (INIS)

Li Guoping; Yang Lusheng; Huang Qunce; Qin Guangyong

2008-01-01

Pollen grains of Pinus thunbergii Parl. (Japanese black pine) were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implantation significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for continuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam implantation and is involved in mediating certain subsequent cytological changes.

N Reactor pressure tube 2566 postirradiation examination

International Nuclear Information System (INIS)

Scott, K.V.

1978-01-01

Pressure tube 2566 was removed from N Reactor in July, 1977 to initiate the postirradiation examination program required by the Technical Specifications. Destructive examination of the pressure tube, after a maximum accumulated fluence of 4.6 x 10 21 n/cm 2 (E > 1 MeV), was conducted at the Hanford Engineering Development Laboratory to determine the effects of reactor service on the mechanical properties and hydrogen absorption and corrosion characteristics of the pressure tube. Tube 2566 is the sixth tube removed for destructive examination since the initial reactor startup. Evaluation of test results reveal that no significant detrimental changes have occurred in the parameters studied, since the last tube was removed in 1974

Experimental study of micro-shock tube flow

Energy Technology Data Exchange (ETDEWEB)

Park, Jin Ouk; Kim, Gyu Wan; Rasel, Md. Alim Iftakhar [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of); Kim, Heuy Dong [Fire Research Center, Korea Institute of Civil Engineering and Building Technology, Hwasung (Korea, Republic of)

2015-03-15

The flow characteristics in micro shock tube are investigated experimentally. Studies were carried out using a stainless steel micro shock tube. Shock and expansion wave was measured using 8 pressure sensors. The initial pressure ratio was varied from 4.3 to 30.5, and the diameter of tube was also changed from 3 mm to 6 mm. Diaphragm conditions were varied using two types of diaphragms. The results obtained show that the shock strength in the tube becomes stronger for an increase in the initial pressure ratio and diameter of tube. For the thinner diaphragm, the highest shock strength was found among varied diaphragm condition. Shock attenuation was highly influenced by the diameter of tube.

Non-destructive controls in the steel tube industry

International Nuclear Information System (INIS)

Mondot, J.

1978-01-01

The main non-destructive control methods in the tube industry are reviewed: eddy currents, particularly well adapted to small tubes; magnetoscopic testing for weldless tubes; ultrasonic waves widely used for thick weldless tubes and weldings; radiography, to examine tube ends and the known questionable zones; measure of diameters by laser [fr

Self-shielding flex-circuit drift tube, drift tube assembly and method of making

Science.gov (United States)

Jones, David Alexander

2016-04-26

The present disclosure is directed to an ion mobility drift tube fabricated using flex-circuit technology in which every other drift electrode is on a different layer of the flex-circuit and each drift electrode partially overlaps the adjacent electrodes on the other layer. This results in a self-shielding effect where the drift electrodes themselves shield the interior of the drift tube from unwanted electro-magnetic noise. In addition, this drift tube can be manufactured with an integral flex-heater for temperature control. This design will significantly improve the noise immunity, size, weight, and power requirements of hand-held ion mobility systems such as those used for explosive detection.

21 CFR 868.5975 - Ventilator tubing.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ventilator tubing. 868.5975 Section 868.5975 Food... DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5975 Ventilator tubing. (a) Identification. Ventilator tubing is a device intended for use as a conduit for gases between a ventilator and a patient...

Disc-Donut-Tube wear test report, Phase I

International Nuclear Information System (INIS)

Kowal, K.; Knaus, S.E.

1976-06-01

The report describes a test program which simulated the wear-inducing conditions in the AI Prototype CRBR Steam Generator. This was accomplished by simulating the wear inducing loading and motion of a steam tube against ''disc-donut'' tube spacer plates. It was found that 2- 1 / 4 Cr-1 Mo tubes, wearing against 2- 1 / 4 Cr-l Mo tube spacer plates, seized and galled as deep as .017 inches. Inconel 718 tube spacer plates uniformly wore the tubes as deep as .012 in. Aluminum bronze inserts wore as deep as .003 inches into the tube

Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

International Nuclear Information System (INIS)

Bucholz, J.A.

2000-01-01

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source

Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

Energy Technology Data Exchange (ETDEWEB)

Bucholz, J.A.

2000-07-01

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source.

Evaluation of steam generator tube integrity during earthquakes

Energy Technology Data Exchange (ETDEWEB)

Kusakabe, Takaya; Kodama, Toshio [Mitsubishi Heavy Industries Ltd., Kobe (Japan). Kobe Shipyard and Machinery Works; Takamatsu, Hiroshi; Matsunaga, Tomoya

1999-07-01

This report shows an experimental study on the strength of PWR steam generator (SG) tubes with various defects under cyclic loads which simulate earthquakes. The tests were done using same SG tubing as actual plants with axial and circumferential defects with various length and depth. In the tests, straight tubes were loaded with cyclic bending moments to simulate earthquake waves and number of load cycles at which tube leak started or tube burst was counted. The test results showed that even tubes with very long crack made by EDM more than 80% depth could stand the maximum earthquake, and tubes with corrosion crack were far stronger than those. Thus the integrity of SG tubes with minute potential defects was demonstrated. (author)

Research on temperature control and influence of the vacuum tubes with inserted tubes solar heater

Science.gov (United States)

Xiao, L. X.; He, Y. T.; Hua, J. Q.

2017-11-01

A novel snake-shape vacuum tube with inserted tubes solar collector is designed in this paper, the heat transfer characteristics of the collector are analyzed according to its structural characteristics, and the influence of different working temperature on thermal characteristics of the collector is studied. The solar water heater prototype consisting of 14 vacuum tubes with inserted tubes is prepared, and the hot water storage control subsystem is designed by hysteresis comparison algorithm. The heat characteristic of the prototype was experimentally studied under hot water output temperature of 40-45°C, 50-55°C and 60-65°C. The daily thermal efficiency was 64%, 50% and 46%, respectively. The experimental results are basically consistent with the theoretical analysis.

Inspection tool for butt-welded tubing

Science.gov (United States)

Horman, D. P.

1977-01-01

Inspection tool for tubing consists of metal casing housing elastic collar. Collar is clamped around weld site under test. Leakage through weld is contained within chamber and is bled to detector via tubing attached to fitting. Tool, originally designed to detect fluid leakage in tubing, can be used to detect gas leaks.

NEI You Tube Videos: Amblyopia

Medline Plus

Full Text Available ... YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia ... *PDF files require the free Adobe® Reader® software for viewing. This website is maintained by the ...

Cladding tube manufacturing technology

International Nuclear Information System (INIS)

Hahn, R.; Jeong, Y. H.; Baek, B. J.; Kim, K. H.; Kim, S. J.; Choi, B. K.; Kim, J. M.

1999-04-01

This report gives an overview of the manufacturing routine of PWR cladding tubes. The routine essentially consists of a series of deformation and annealing processes which are necessary to transform the ingot geometry to tube dimensions. By changing shape, microstructure and structure-related properties are altered simultaneously. First, a short overview of the basics of that part of deformation geometry is given which is related to tube reducing operations. Then those processes of the manufacturing routine which change the microstructure are depicted, and the influence of certain process parameters on microstructure and material properties are shown. The influence of the resulting microstructure on material properties is not discussed in detail, since it is described in my previous report A lloy Development for High Burnup Cladding . Because of their paramount importance still up to now, and because manufacturing data and their influence on properties for other alloys are not so well established or published, the descriptions are mostly related to Zry4 tube manufacturing, and are only in short for other alloys. (author). 9 refs., 46 figs

Cladding tube manufacturing technology

Energy Technology Data Exchange (ETDEWEB)

Hahn, R. [Kraftwerk Union AG, Mulheim (Germany); Jeong, Y.H.; Baek, B.J.; Kim, K.H.; Kim, S.J.; Choi, B.K.; Kim, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1999-04-01

This report gives an overview of the manufacturing routine of PWR cladding tubes. The routine essentially consists of a series of deformation and annealing processes which are necessary to transform the ingot geometry to tube dimensions. By changing shape, microstructure and structure-related properties are altered simultaneously. First, a short overview of the basics of that part of deformation geometry is given which is related to tube reducing operations. Then those processes of the manufacturing routine which change the microstructure are depicted, and the influence of certain process parameters on microstructure and material properties are shown. The influence of the resulting microstructure on material properties is not discussed in detail, since it is described in my previous report 'Alloy Development for High Burnup Cladding.' Because of their paramount importance still up to now, and because manufacturing data and their influence on properties for other alloys are not so well established or published, the descriptions are mostly related to Zry4 tube manufacturing, and are only in short for other alloys. (author). 9 refs., 46 figs.

Clinical tube weaning supported by hunger provocation in fully-tube-fed children.

Science.gov (United States)

Hartdorff, Caroline M; Kneepkens, C M Frank; Stok-Akerboom, Anita M; van Dijk-Lokkart, Elisabeth M; Engels, Michelle A H; Kindermann, Angelika

2015-04-01

Children with congenital malformations, mental retardation, and complex early medical history frequently have feeding problems. Although tube feeding is effective in providing the necessary energy and nutrients, it decreases the child's motivation to eat and may lead to oral aversion. In this study, we sought to confirm our previous results, showing that a multidisciplinary clinical hunger provocation program may lead to quick resumption of oral feeding. In a crossover study, 22 children of 9 to 24 months of age who were fully dependent on tube feeding were randomly assigned to one of two groups: group A, intervention group (2-week multidisciplinary clinical hunger provocation program); and group B, control group (4-week outpatient treatment by the same multidisciplinary team). Patients failing one treatment were reassigned to the other treatment group. Primary outcome measures were at least 75% orally fed at the conclusion of the intervention and fully orally fed and gaining weight 6 months after the intervention. In group A, 9/11 patients were successfully weaned from tube feeding (2 failures: 1 developed ulcerative colitis, 1 drop-out). In group B, only 1 patient was weaned successfully; 10/11 were reassigned to the clinical hunger provocation program, all being weaned successfully. Six months after the intervention, 1 patient had to resume tube feeding. In total, in the control group, 1/11 (9%) was weaned successfully as compared with 18/21 (86%) in the hunger provocation group (P hunger provocation is an effective short-term intervention for weaning young children from tube feeding.

A continuous acceleration tube of ions under 200 KV; Un tube d'acceleration continue d'ions sous 200 KV

Energy Technology Data Exchange (ETDEWEB)

Mongodin, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1954-07-01

The realization of an Van de Graaff accelerator required, for the preliminary studies, the construction of a small proton accelerator, functioning at 200 kV in order to resolve some parasitic effects inherent to the accelerators tubes. The aim of this report is to describe the different organs of the accelerator tube, to explain the operating system and to encode their characteristics. The report first presents the ion source and the beam buncher permitting to inject in the accelerator tube particles of about 9 kV and very batched in a thin beam of circular section. Then the study explain the tube characteristics considered like optic system. A method to obtain precise calculation of particle trajectories is exposed. Aberrations of the system were discussed and balance of the currents on all electrodes inside the tube for different regimes of working were provided. The influence of the residual pressure in the tube were explained. The report finally ends on a part of the fundamental problem of the straining occurring inside the tubes accelerators under high tension. (M.B.) [French] La realisation d n accelerateur du type Van de Graaff a necessite, entre autres etudes preliminaires, la construction d'un petit accelerateur de protons, fonctionnant sous 200 kV afin d'eclaircir certains effets parasites propres aux tubes accelerateurs. L'objet de ce rapport est de decrire les differents organes du tube accelerateur, d'en expliquer le fonctionnement et de chiffrer leurs caracteristiques. Le memoire presente d'abord la source d'ions et le canon permettant d'injecter dans le tube accelerateur des particules de 9 kV environ et bien groupees dans un faisceau fin de section circulaire. Puis il passe a l'etude du tube considere comme systeme optique. Une methode utilisee pour le calcul precis des trajectoires des particules y est exposee. Il aborde le probleme des aberrations de ce systeme et fournit par la suite le bilan des courants sur toutes les electrodes a l

Structural integrity assessment of steam generator tubes deteriorated through primary water stress corrosion cracking in transition region of tube expansion

International Nuclear Information System (INIS)

Silveira, Helvecio Carlos Klinke da

2002-01-01

In PWR plants, steam generator tube degradation has been one of the most important economical concerns, besides causing operational safety problems. In this work, a survey of steam generator tube degradation modes is done. Degradation mechanisms and influence factors are introduced and discussed. The importance of stress corrosion cracking, especially in transition region of tube expansion zone, is underlined. The actual steam generator tube plugging criteria are conservative. Proposed alternative criteria are introduced and discussed. Distinction is done to structural integrity assessment of defective tubes. Real data of tube defect indications of axial cracks in expansion transition zone due to primary water stress corrosion cracking are used in analysis. Results allow discussing application aspects of deterministic and probabilistic criteria on structural integrity assessment of tubes with defect indications. Applied models are specifics, but the application of concept may be extended to other steam generator tube degradation modes. (author)

Tube temperature rise limits: Boiling considerations

Energy Technology Data Exchange (ETDEWEB)

Vanderwater, R.G.

1952-03-26

A revision of tube power limits based on boiling considerations was presented earlier. The limits were given on a basis of tube power versus header pressure. However, for convenience of operation, the limits have been converted from tube power to permissible water temperature rise. The permissible {triangle}t`s water are given in this document.

Electron tube

Science.gov (United States)

Suyama, Motohiro [Hamamatsu, JP; Fukasawa, Atsuhito [Hamamatsu, JP; Arisaka, Katsushi [Los Angeles, CA; Wang, Hanguo [North Hills, CA

2011-12-20

An electron tube of the present invention includes: a vacuum vessel including a face plate portion made of synthetic silica and having a surface on which a photoelectric surface is provided, a stem portion arranged facing the photoelectric surface and made of synthetic silica, and a side tube portion having one end connected to the face plate portion and the other end connected to the stem portion and made of synthetic silica; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the photoelectric surface, and made of synthetic silica; and an electron detector arranged on the projection portion, for detecting electrons from the photoelectric surface, and made of silicon.

The impact of a chest tube management protocol on the outcome of trauma patients with tube thoracostomy.

Science.gov (United States)

de Abreu, Emanuelle Maria Sávio; Machado, Carla Jorge; Pastore Neto, Mario; de Rezende Neto, João Baptista; Sanches, Marcelo Dias

2015-01-01

to investigate the effect of standardized interventions in the management of tube thoracostomy patients and to assess the independent effect of each intervention. A chest tube management protocol was assessed in a retrospective cohort study. The tube thoracostomy protocol (TTP) was implemented in August 2012, and consisted of: antimicrobial prophylaxis, chest tube insertion in the operating room (OR), admission post chest tube thoracostomy (CTT) in a hospital floor separate from the emergency department (ED), and daily respiratory therapy (RT) sessions post-CTT. The inclusion criteria were, hemodynamic stability, patients between the ages of 15 and 59 years, and injury severity score (ISS) chest wall, lung, and pleura. During the study period 92 patients were managed according to the standardized protocol. The outcomes of those patients were compared to 99 patients treated before the TTP. Multivariate logistic regression analysis was performed to assess the independent effect of each variable of the protocol on selected outcomes. Demographics, injury severity, and trauma mechanisms were similar among the groups. As expected, protocol compliance increased after the implementation of the TTP. There was a significant reduction (pchest tube days. Respiratory therapy was independently linked to significant reduction (pchest tube insertion was associated with significant (ptrauma patients.

Measuring of tube expansion

International Nuclear Information System (INIS)

Vogeleer, J. P.

1985-01-01

The expansion of the primary tubes or sleeves of the steam generator of a nuclear reactor plant are measured while the tubes or sleeves are being expanded. A primary tube or sleeve is expanded by high pressure of water which flows through a channel in an expander body. The water is supplied through an elongated conductor and is introduced through a connector on the shank connected to the conductor at its outer end. A wire extends through the mandrel and through the conductor to the end of the connector. At its inner end the wire is connected to a tapered pin which is subject to counteracting forces produced by the pressure of the water. The force on the side where the wire is connected to the conductor is smaller than on the opposite side. The tapered pin is moved in the direction of the higher force and extrudes the wire outwardly of the conductor. The tapered surface of the tapered pin engages transverse captive plungers which are maintained in engagement with the expanding tube or sleeve as they are moved outwardly by the tapered pin. The wire and the connector extend out of the generator and, at its outer end, the wire is connected to an indicator which measures the extent to which the wire is moved by the tapered pin, thus measuring the expansion of the tube or sleeve as it progresses

The local clinical validation of a new lithium heparin tube with a barrier: BD Vacutainer® Barricor LH Plasma tube

Science.gov (United States)

Arslan, Fatma Demet; Karakoyun, Inanc; Basok, Banu Isbilen; Aksit, Merve Zeytinli; Baysoy, Anil; Ozturk, Yasemin Kilic; Guclu, Yusuf Adnan; Duman, Can

2017-01-01

Introduction Although serum-providing blood tubes with a barrier are still widely used due to their significant advantages, the use of blood tubes with a barrier to provide plasma is becoming widespread. We compared 22 analytes in a BD Vacutainer® Barricor LH Plasma tube for local clinical validation of this new lithium heparin tube with a barrier. Materials and methods Samples from 44 volunteers were collected in different tubes (Becton Dickinson and Company): Z tube without additive (reference), clot-activator tube with gel (SST), lithium heparin tube without gel (LiH), and lithium heparin tube with barrier (Barricor). Analyte concentrations in different tubes were compared with the reference tube. All tubes were also evaluated according to additional testing (different centrifugation durations, blood-sampling techniques and individual differences). Results Aspartate aminotransferase (AST), glucose (Glc), potassium (K), lactate dehydrogenase (LD), sodium (Na), and total protein (TP) had a significant bias in Barricor (9.19%, - 3.24%, - 4.88%, 21.60%, - 0.40%, 5.03%, respectively) relative to the reference tube. There was no statistical difference between different centrifugation durations and individual differences for AST, K and LD in LiH and/or Barricor (P > 0.05). There was a significant bias for LD between LiH and Barricor in terms of blood-sampling techniques (21.2% and 12.4%, respectively). Conclusions Recently, the use of plasma has become prominent due to some of its advantages. In this study, plasma AST, K, LD, Glc and TP levels in Barricor were clinically different in comparison to serum. The results of additional tests showed that higher levels of LD in Barricor did not result from haemolysis, and they might be related to other factors including number of platelets, cellular fragility, or functional environment. PMID:28900369

The local clinical validation of a new lithium heparin tube with a barrier: BD Vacutainer® Barricor LH Plasma tube.

Science.gov (United States)

Arslan, Fatma Demet; Karakoyun, Inanc; Basok, Banu Isbilen; Aksit, Merve Zeytinli; Baysoy, Anil; Ozturk, Yasemin Kilic; Guclu, Yusuf Adnan; Duman, Can

2017-10-15

Although serum-providing blood tubes with a barrier are still widely used due to their significant advantages, the use of blood tubes with a barrier to provide plasma is becoming widespread. We compared 22 analytes in a BD Vacutainer® Barricor LH Plasma tube for local clinical validation of this new lithium heparin tube with a barrier. Samples from 44 volunteers were collected in different tubes (Becton Dickinson and Company): Z tube without additive (reference), clot-activator tube with gel (SST), lithium heparin tube without gel (LiH), and lithium heparin tube with barrier (Barricor). Analyte concentrations in different tubes were compared with the reference tube. All tubes were also evaluated according to additional testing (different centrifugation durations, blood-sampling techniques and individual differences). Aspartate aminotransferase (AST), glucose (Glc), potassium (K), lactate dehydrogenase (LD), sodium (Na), and total protein (TP) had a significant bias in Barricor (9.19%, - 3.24%, - 4.88%, 21.60%, - 0.40%, 5.03%, respectively) relative to the reference tube. There was no statistical difference between different centrifugation durations and individual differences for AST, K and LD in LiH and/or Barricor (P > 0.05). There was a significant bias for LD between LiH and Barricor in terms of blood-sampling techniques (21.2% and 12.4%, respectively). Recently, the use of plasma has become prominent due to some of its advantages. In this study, plasma AST, K, LD, Glc and TP levels in Barricor were clinically different in comparison to serum. The results of additional tests showed that higher levels of LD in Barricor did not result from haemolysis, and they might be related to other factors including number of platelets, cellular fragility, or functional environment.

Failure analysis of retired steam generator tubings

Energy Technology Data Exchange (ETDEWEB)

Kim, Hong Pyo; Kim, J. S.; Hwang, S. S. and others

2005-04-15

Degradation of steam generator leads to forced outage and extension of outage, which causes increase in repair cost, cost of purchasing replacement power and radiation exposure of workers. Steam generator tube rupture incident occurred in Uljin 4 in 2002, which made public sensitive to nuclear power plant. To keep nuclear energy as a main energy source, integrity of steam generator should be demonstrated. Quantitative relationship between ECT(eddy current test) signal and crack size is needed in assesment of integrity of steam generator in pressurized water reactor. However, it is not fully established for application in industry. Retired steam generator of Kori 1 has many kinds of crack such as circumferential and axial primary water stress corrosion crack and outer diameter stress corrosion crack(ODSCC). So, it can be used in qualifying and improving ECT technology and in condition monitoring assesment for crack detected in ISI(in service inspection). In addition, examination of pulled tube of Kori 1 retired steam generator will give information about effectiveness of non welded sleeving technology which was employed to repair defect tubes and remedial action which was applied to mitigate ODSCC. In this project, hardware such as semi hot lab. for pulled tube examination and modification transportation cask for pulled tube and software such as procedure of transportation of radioactive steam generator tube and non-destructive and destructive examination of pulled tube were established. Non-destructive and destructive examination of pulled tubes from Kori 1 retired steam generator were performed in semi hot lab. Remedial actions applied to Kori 1 retired steam generator, PWSCC trend and bulk water chemistry and crevice chemistry in Kori 1 were evaluated. Electrochemical decontamination technology for pulled tube was developed to reduce radiation exposure and enhance effectiveness of pulled tube examination. Multiparameter algorithm developed at ANL, USA was

Cutting device for a local power range monitor tube

International Nuclear Information System (INIS)

Watanabe, Shigeru; Tsuji, Teruaki.

1976-01-01

Object: To provide a combination of a lifting device for a local power range monitor (LPRM) tube, a cutter and a transfer machine to safely and securely cut the LPRM tube under water. Structure: An LPRM tube is gripped by an LPRM tube gripper, which is moved up and down by a chain drive, through a flexture corrector, and the tip of the LPRM tube is held and released from the LPRM tube gripper so as to be threaded into an LPRM tube cutter to grip it by a transfer gripper of an LPRM tube transfer machine, after which the LPRM tube cutter is operated under pressure water to cut the LPRM tube with a cutter edge so that a cut portion is closed. (Yoshino, Y.)

Enhanced Evaporation and Condensation in Tubes

Science.gov (United States)

Honda, Hiroshi

A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

Lava tubes - Potential shelters for habitats

Science.gov (United States)

Horz, F.

Natural caverns occur on the moon in the form of 'lava tubes', which are the drained conduits of underground lava rivers. The inside dimensions of these tubes measure tens to hundreds of meters, and their roofs are expected to be thicker than 10 meters. Consequently, lava tube interiors offer an environment that is naturally protected from the hazards of radiation and meteorite impact. Further, constant, relatively benign temperatures of -20 C prevail. These are extremely favorable environmental conditions for human activities and industrial operations. Significant operational, technological, and economical benefits might result if a lunar base were constructed inside a lava tube.

Tubing For Sampling Hydrazine Vapor

Science.gov (United States)

Travis, Josh; Taffe, Patricia S.; Rose-Pehrsson, Susan L.; Wyatt, Jeffrey R.

1993-01-01

Report evaluates flexible tubing used for transporting such hypergolic vapors as those of hydrazines for quantitative analysis. Describes experiments in which variety of tubing materials, chosen for their known compatibility with hydrazine, flexibility, and resistance to heat.

Horizontal beam tubes in FRM-II

International Nuclear Information System (INIS)

Coors, D.; Vanvor, D.

2001-01-01

The new research reactor in Garching FRM-II is equipped with 10 leak tight horizontal beam tubes (BT1 - BT10), each of them consisting of a beam tube structure taking an insert with neutron channels. The design of all beam tube structures is similar whereas the inserts are adapted to the special requirements of the using of each beam tube. Inside the reflector tank the beam tube structures are shaped by the inner cones which are made of Al-alloy with circular and rectangular cross sections. They are located in the region of maximum neutron flux (exception BT10), they are directly connected to the flanges of the reflector tank, their lengths are about 1.5 m (exception BT10) and their axes are directed tagentially to the core centre thus contributing to a low γ-noise at the experiments. (orig.)

Early Experience with the StopLoss Jones Tube.

Science.gov (United States)

Bagdonaite, Laura; Pearson, Andrew R

2015-06-01

Extrusion is the most common reason for failure after Jones tube placement. The StopLoss Jones tube (SLJT) is a new innovation in Jones tubes that incorporates a flexible silicone internal flange to resist extrusion. We present our early experience of using this new tube and associated introducer system. We retrospectively analysed the case notes of a single surgeon consecutive series of patients having SLJT placement from November 2011 to November 2013. 29 SLJTs were placed in 25 eyes of 19 patients. Tube follow-up ranged from 1-25 months (mean 10 months) with a total of 291 tube-months. The indications for SLJT placement were: previous LJT complications (52%), failed canalicular-DCR surgery (31%), primary placement for inoperable canalicular occlusion (14%) and patent non-functioning DCR (3%). Tube length ranged from 10-16 mm. The tube introducer system was simple and effective and there were no intra-operative complications. The tube extrusion rate was 0%. Complications occurred in 5 tubes: 1 was too long, and 4 others (14%) developed conjunctival overgrowth/medial tube migration. Patient satisfaction with the tube was: 86% fully satisfied, 10% was moderately satisfied, 3% not satisfied. The overall final surgical success rate at last follow-up was 92%. In this short follow-up initial study the SLJT is simple to use and has a high rate of success and patient satisfaction. The addition of the internal silicone flange appears to prevent the previously common problem of extrusion.

Mini implant supported molar tubes: A novel method for attaching the molar tubes

Directory of Open Access Journals (Sweden)

Nitin V Muralidhar

2017-01-01

Full Text Available Banding or bonding procedures have been the only means of attaching molar tubes onto the permanent molar teeth till date in the field of orthodontics. This clinical innovation aims to include the use of mini implant for the purpose of attaching the molar tubes thereby eliminating the iatrogenic effects of banding and bonding of the teeth.

Heat removal capability of divertor coaxial tube assembly

International Nuclear Information System (INIS)

Shibui, Masanao; Nakahira, Masataka; Tada, Eisuke; Takatsu, Hideyuki

1994-05-01

To deal with high power flowing in the divertor region, an advanced divertor concept with gas target has been proposed for use in ITER/EDA. The concept uses a divertor channel to remove the radiated power while allowing neutrals to recirculate. Candidate channel wall designs include a tube array design where many coaxial tubes are arranged in the toroidal direction to make louver. The coaxial tube consists of a Be protection tube encases many supply tubes wound helically around a return tube. V-alloy and hardened Cu-alloy have been proposed for use in the supply and return tubes. Some coolants have also been proposed for the design including pressurized He and liquid metals, because these coolants are consistent with the selection of coolants for the blanket and also meet the requirement of high temperature operation. In the coaxial tube design, the coolant area is restricted and brittle Be material is used under severe thermal cyclings. Thus, to obtain the coaxial tube with sufficient safety margin for the expected fusion power excursion, it is essential to understand its applicability limit. The paper discusses heat removal capability of the coaxial tube and recommends some design modifications. (author)

Conditioning and breakdown phenomena in accelerator tubes

International Nuclear Information System (INIS)

Skorka, S.J.

1979-01-01

Important breakdown mechanisms in accelerator tubes are reviewed, and discharge phenomena in NEC tubes are deduced from the surface appearance of the electrodes and insulators of a used tube. Microphotos of these surfaces are shown

Simulation studies on Tube End Expansion of AA2014 Alloy Tubes

Science.gov (United States)

Venugopal, L.; Prasad, N. E. C.; Geeta Krishna, P.; Praveen, L.

2018-03-01

End forming is defined as forming the end of tubular forms either by inverting the tube or by expanding it. It finds application in many fields such as in automotive and aerospace sectors as power transmission elements, fuel lines, exhaust pipes etc. The main aim of the present work is to expand the AA2014 alloy tubes with different die sets without any fracture. Deform 2D software was used for performing simulations on expanding the tubes with different die set (punch) values having differed forming angles (α = 15°, 30° and 45°) and expansion ratios (rp/r0 = 1.39, 1.53 and 1.67). Experiments were also conducted and the results correlate with the simulation results. The results shows that for the punch having less cone angle (α) values the linear displacement is more rather than higher cone angles. But in the case of higher cone angles the radial displacement is more than the linear displacement.

Heat treated tube for cladding nuclear fuel element

International Nuclear Information System (INIS)

Eddens, F.C.; White, D.W.; Harmon, J.L.

1983-01-01

The zirconium alloy tube comprises a metallurgical gradient across the width of the tube wall wherein the tube has a more corrosion-resistant metallurgical condition at the outer circumference and a less corrosion-resistant metallurgical condition at the inner circumference. The metallurgical gradient can be generated by heating an outer circumferential portion of the tube to the high alpha or mixed alpha plus beta range while maintaining the inner surface at a lower temperature, followed by cooling of the tube. Preferably the tube is made of Zircaloy. (author)

Drift tubes of Linac 2

CERN Multimedia

Photographic Service

1977-01-01

Being redied for installation, those at the right are for tank 1, those on the left for tank 2. Contrary to Linac 1, which had drift-tubes supported on stems, here the tubes are suspended, for better mechanical stability.

NEI You Tube Videos: Amblyopia

Medline Plus

Full Text Available ... Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract Convergence ... is maintained by the NEI Office of Science Communications, Public Liaison, and Education. Technical questions about this ...

Measurement of unsteady flow forces in inline and staggered tube bundles with fixed and vibrating tubes

International Nuclear Information System (INIS)

Michel, A.; Heinecke, E.; Decken, C.B. von der.

1986-01-01

Unsteady flow forces arising in heat exchangers with cross-flow may lead to serious vibrations of the tubes. These vibrations can destroy the tubes in the end supports or in the baffles, which would require expensive repairs. The flow forces reach unexpectedly by high values if the vibration of the tube intensifies these forces. To clear up this coupling mechanism the flow forces and the vibration amplitude were measured simultaneously in a staggered and in an inline tube bundle. Considering the tube as a one-mass oscillator excited by the flow force, the main parameters can be derived, i.e. dynamic pressure, reduced mass, eigenfrequency and damping. These parameters form a dimensionless model number describing the coherence of the vibration amplitude and the force coefficient. The validity of this number has been confirmed by varying the test conditions. With the aid of this model number, the expected force coefficient can be calculated and then using a finite-element program information can be obtained about mechanical tensions and the lifetime of the heat exchanger tubes. With this model number the results of other authors, who measured the vibration amplitude only, could be confirmed in good agreement. The experiments were carried out in air with Reynolds numbers 10 4 5 . (orig.) [de

French steam generator tubes: an overview of degradations

International Nuclear Information System (INIS)

Buisine, D.; Bouvier, O. de; Rupa, N.; Thebault, Y.; Barbe, V.; Pitner, P.

2011-01-01

The various damages (corrosion, fatigue cracks, wear, ...) observed on steam generator (SG) tubes are presented here as well as the techniques used to characterize these damages. The SG are equipped with tubes of 3 materials: 600 MA, 600 TT and 690 TT. Concerning PWSCC of 600 MA and 600 TT tubes, beyond the damages usually observed (corrosion in expansion transition zone and in 600 MA tubes small radius U-bend zone), a new event is to be noted: the phenomenon of denting (presumably induced by the deposit of sludge on the tubesheet) has induced circumferential cracking of the tube expansion transition zone. Concerning ODSCC of 600 MA tubes, beyond the classically observed damages (IGA and IGSCC in expansion transition zone and in TSP crevice), a new event is to be noted: the occurrence of circumferential cracks in tube- TSP crevice. Concerning fatigue cracking, two events have to be noted at upper TSP level in Cruas 1 and Cruas 4 units and in Fessenheim 2 unit. The first (Cruas) was due to the blockage in the broached hole tube support plate which can create critical velocity ratios for some tubes and the second (Fessenheim) to high-cycle fatigue. Concerning wear damage, beyond what is usually observed in the U-bend zone facing the anti-vibration bars (AVB), a new event is to be noted: a wear at TSP level is observed on SG equipped with an economizer, the wear indications being located at TSP 7 and 8 level, on outer tubes close to the central lane. The number of tubes plugged for ODSCC has declined due to the progressive replacement of SG with Alloy 600 MA tubing. Starting in 2004, the increasing plugging of 690 tubing is mainly due to AVB wear. Since 2006, extensive preventive plugging campaigns for tubes at risk of high-cycle fatigue at the upper support plate are performed. Risk of high-cycle fatigue has consequently become the dominant mechanism inducing plugging. PWSCC is the second dominant mechanism which affects 600 MA and 600 TT tube bundles: extensive

Fluid mechanics and heat transfer spirally fluted tubing

Science.gov (United States)

Larue, J. C.; Libby, P. A.; Yampolsky, J. S.

1981-08-01

The objective of this program is to develop both a qualitative and a quantitative understanding of the fluid mechanics and heat transfer mechanisms that underlie the measured performance of the spirally fluted tubes under development at General Atomic. The reason for the interest in the spirally fluted tubes is that results to date have indicated three advantages to this tubing concept: The fabrication technique of rolling flutes on strip and subsequently spiralling and simultaneously welding the strip to form tubing results in low fabrication costs, approximately equal to those of commercially welded tubing. The heat transfer coefficient is increased without a concomitant increase of the friction coefficient on the inside of the tube. In single-phase axial flow of water, the helical flutes continuously induce rotation of the flow both within and without the tube as a result of the effect of curvature. An increase in condensation heat transfer on the outside of the tube is achieved. In a vertical orientation with fluid condensing on the outside of the helically fluted tube, the flutes provide a channel for draining the condensed fluid.

Tubing Cutter is Activated Hydraulically

Science.gov (United States)

Mcsmith, D. G.; Richardson, J. I.

1983-01-01

Hydraulically-actuated tubing cutter severs tubing when operator squeezes handle grip. "Gooseneck" extension enables cutter to be used in areas where accessiblity is limited. Cutter has potential as flight-line tool and is useful in automobile and fire rescue work.

Is tube feeding futile in advanced dementia?

Science.gov (United States)

Lynch, Matthew C.

2016-01-01

It is controversial whether tube feeding in people with dementia improves nutritional status or prolongs survival. Guidelines published by several professional societies cite observational studies that have shown no benefit and conclude that tube feeding in patients with advanced dementia should be avoided. However, all studies on tube feeding in dementia have major methodological flaws that invalidate their findings. The present evidence is not sufficient to justify general guidelines. Patients with advanced dementia represent a very heterogeneous group, and evidence demonstrates that some patients with dementia benefit from tube feeding. However, presently available guidelines make a single recommendation against tube feeding for all patients. Clinicians, patients, and surrogates should be aware that the guidelines and prior commentary on this topic tend both to overestimate the strength of evidence for futility and to exaggerate the burdens of tube feeding. Shared decision making requires accurate information tailored to the individual patient's particular situation, not blanket guidelines based on flawed data. Lay Summary: Many doctors believe that tube feeding does not help people with advanced dementia. Scientific studies suggest that people with dementia who have feeding tubes do not live longer or gain weight compared with those who are carefully hand fed. However, these studies are not very helpful because of flaws in design, which are discussed in this article. Guidelines from professional societies make a blanket recommendation against feeding tubes for anyone with dementia, but an individual approach that takes each person's situation into account seems more appropriate. Patients and surrogates should be aware that the guidelines on this topic tend both to underestimate the benefit and exaggerate the burdens of tube feeding. PMID:27833208

Formability of Micro-Tubes in Hydroforming

International Nuclear Information System (INIS)

Hartl, Christoph; Anyasodor, Gerald; Lungershausen, Joern

2011-01-01

Micro-hydroforming is a down-scaled metal forming process, based on the expansion of micro-tubes by internal pressurization within a die cavity. The objective of micro-hydroforming is to provide a technology for the economic mass production of complex shaped hollow micro-components. Influence of size effects in metal forming processes increases with scaling down of metal parts. Investigations into the change in formability of micro-tubes due to metal part scaling down constituted an important subject within the conducted fundamental research work. Experimental results are presented, concerning the analysis of the formability of micro-tubes made from stainless steel AISI 304 with an outer diameter of 800 μm and a wall thickness of 40 μm. An average ratio of tube wall thickness to grain size of 1.54 of up to 2.56 was analyzed. Miniaturised mechanical standard methods as well as bulge tests with internal hydrostatic pressurization of the tubular specimens were applied to analyze the influence of size-dependent effects. A test device was developed for the bulge experiments which enabled the pressurization of micro-tubes with internal pressures up to 4000 bar. To determine the attainable maximum achievable expansion ratio the tubes were pressurized in the bulge tests with increasing internal pressure until instability due to necking and subsequent bursting occurred. Comparisons with corresponding tests of macro-tubes, made from the here investigated material, showed a change in formability of micro-tubes which was attributed to the scaling down of the hydroforming process. In addition, a restricted applicability of existing theoretical correlations for the determination of the maximum pressure at bursting was observed for down-scaled micro-hydroforming.

Improved drainage with active chest tube clearance.

Science.gov (United States)

Shiose, Akira; Takaseya, Tohru; Fumoto, Hideyuki; Arakawa, Yoko; Horai, Tetsuya; Boyle, Edward M; Gillinov, A Marc; Fukamachi, Kiyotaka

2010-05-01

This study was performed to evaluate the efficacy of a novel chest drainage system. This system employs guide wire-based active chest tube clearance to improve drainage and maintain patency. A 32 Fr chest tube was inserted into pleural cavities of five pigs. On the left, a tube was connected to the chest canister, and on the right, the new system was inserted between the chest tube and chest canister. Acute bleeding was mimicked by periodic infusion of blood. The amount of blood drained from each chest cavity was recorded every 15 min for 2 h. After completion of the procedure, all residual blood and clots in each chest cavity were assessed. The new system remained widely patent, and the amount of drainage achieved with this system (670+/-105 ml) was significantly (P=0.01) higher than that with the standard tube (239+/-131 ml). The amount of retained pleural blood and clots with this system (150+/-107 ml) was significantly (P=0.04) lower than that with the standard tube (571+/-248 ml). In conclusion, a novel chest drainage system with active tube clearance significantly improved drainage without tube manipulations. 2010 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.

Testing and analysis of tube voltage and tube current in the radiation generator for mammography

International Nuclear Information System (INIS)

Jung, Hong Ryang; Hong, Dong Hee; Han, Beom Hui

2014-01-01

Breast shooting performance management and quality control of the generator is applied to the amount of current IEC(International Electrotechnical Commission) 60601-2-45 tube voltage and tube current are based on standards that were proposed in the analysis of the test results were as follows. Tube voltage according to the value of the standard deviation by year of manufacture from 2001 to 2010 as a 42-3.15 showed the most significant, according to the year of manufacture by tube amperage value of the standard deviation to 6.38 in the pre-2000 showed the most significant , manufactured after 2011 the standard deviation of the devices, the PAE(Percent Average Error) was relatively low. This latest generation device was manufactured in the breast of the tube voltage and tube diagnosed shooting the correct amount of current to maintain the performance that can be seen. The results of this study as the basis for radiography diagnosed breast caused by using the device's performance and maintain quality control, so the current Food and Drug Administration 'about the safety of diagnostic radiation generator rule' specified in the test cycle during three years of self-inspection radiation on a radiation generating device ensure safety and performance of the device using a coherent X-ray(constancy) by two ultimately able to keep the radiation dose to the public to reduce the expected effect is expected

[How to do - the chest tube drainage].

Science.gov (United States)

Klopp, Michael; Hoffmann, Hans; Dienemann, Hendrik

2015-03-01

A chest tube is used to drain the contents of the pleural space to reconstitute the physiologic pressures within the pleural space and to allow the lungs to fully expand. Indications for chest tube placement include pneumothorax, hemothorax, pleural effusion, pleural empyema, and major thoracic surgery. The most appropriate site for chest tube placement is the 4th or 5th intercostal space in the mid- or anterior- axillary line. Attention to technique in placing the chest tube is vital to avoid complications from the procedure. Applying the step-by-step technique presented, placement of a chest tube is a quick and safe procedure. Complications - frequently occurring when the tube is inserted with a steel trocar - include hemothorax, dislocation, lung lacerations, and injury to organs in the thoracic or abdominal cavity." © Georg Thieme Verlag KG Stuttgart · New York.

A Study on Thermal Performance of a Novel All-Glass Evacuated Tube Solar Collector Manifold Header with an Inserted Tube

Directory of Open Access Journals (Sweden)

Jichun Yang

2015-01-01

Full Text Available A novel all-glass evacuated tube collector manifold header with an inserted tube is proposed in this paper which makes water in all-glass evacuated solar collector tube be forced circulated to improve the performance of solar collector. And a dynamic numerical model was presented for the novel all-glass evacuated tube collector manifold header water heater system. Also, a test rig was built for model validation and comparison with traditional all-glass evacuated tube collector. The experiment results show that the efficiency of solar water heater with a novel collector manifold header is higher than traditional all-glass evacuated tube collector by about 5% and the heat transfer model of water heater system is valid. Based on the model, the relationship between the average temperature of water tank and inserted tube diameter (water mass flow has been studied. The results show that the optimized diameter of inserted tube is 32 mm for the inner glass with the diameter of 47 mm and the water flow mass should be less than 1.6 Kg/s.

Schizophrenia on YouTube.

Science.gov (United States)

Nour, Matthew M; Nour, Murraih H; Tsatalou, Olga-Maria; Barrera, Alvaro

2017-01-01

YouTube ( www.youtube.com ) is the most popular video-sharing Web site on the Internet and is used by medical students as a source of information regarding mental health conditions, including schizophrenia. The accuracy and educational utility of schizophrenia presentations on YouTube are unknown. The purpose of this study was to analyze the accuracy of depictions of psychosis in the context of a diagnosis of schizophrenia (referred to in this article as "acute schizophrenia") on YouTube and to assess the utility of these videos as educational tools for teaching medical students to recognize the clinical features of acute schizophrenia. YouTube was searched for videos purporting to show acute schizophrenia. Eligible videos were independently rated by two consultant psychiatrists on two separate occasions 22 days apart for diagnostic accuracy, psychopathology, and educational utility. Videos (N=4,200) were assessed against predefined inclusion and exclusion criteria. The majority were not eligible for further analysis, mostly because they did not claim to show a patient with schizophrenia (74%) or contained duplicated content (11%). Of 35 videos that met the eligibility and adequacy criteria, only 12 accurately depicted acute schizophrenia. Accurate videos were characterized by persecutory delusions (83%), inappropriate affect (75%), and negative symptoms (83%). Despite the fact that 83% of accurate videos were deemed to have good educational utility compared with 15% of inaccurate videos, accurate and inaccurate videos had similar view counts (290,048 versus 186,124). Schizophrenia presentations on YouTube offer a distorted picture of the condition.

Computation and measurement of calandria tube sag in PHWR

International Nuclear Information System (INIS)

Kim, Tae Ryong; Sohn, Seok Man

2003-01-01

Calandria tubes and liquid injection shutdown system (LISS) tubes in a pressurized heavy water reactor (PHWR) is known to sag due to irradiation creep and growth during plant operation. When the sag of calandria tube becomes bigger, the calandria tube possibly comes in contact with LISS tube crossing beneath and calandria tube. The contact subsequently may cause the damage on the calandria tube resulting in unpredicted outage of the plant. It is therefore necessary to check the gap between the two tubes in order to periodically confirm no contact by using a proper measure during the plant life. An ultrasonic gap measuring probe assembly which can be inserted into two viewing ports of the calandria was developed in Korea and utilized to measure the sags of both tubes in the PHWR. It was found that the centerlines of calandria tubes and liquid injection shutdown system tubes can be precisely detected by ultrasonic wave. The gaps between two tubes were easily obtained from the relative distance of the measured centerline elevations of the tubes. Based on the irradiation creep equation and the measurement data, a computer program to calculate the sags was also developed. With the computer program, the sag at the end of plant life was predicted. (author)

Preliminary Study on Biosynthesis of Bacterial Nanocellulose Tubes in a Novel Double-Silicone-Tube Bioreactor for Potential Vascular Prosthesis

Directory of Open Access Journals (Sweden)

Feng Hong

2015-01-01

Full Text Available Bacterial nanocellulose (BNC has demonstrated a tempting prospect for applications in substitute of small blood vessels. However, present technology is inefficient in production and BNC tubes have a layered structure that may bring danger after implanting. Double oxygen-permeable silicone tubes in different diameters were therefore used as a tube-shape mold and also as oxygenated supports to construct a novel bioreactor for production of the tubular BNC materials. Double cannula technology was used to produce tubular BNC via cultivations with Acetobacter xylinum, and Kombucha, a symbiosis of acetic acid bacteria and yeasts. The results indicated that Kombucha gave higher yield and productivity of BNC than A. xylinum. Bacterial nanocellulose was simultaneously synthesized both on the inner surface of the outer silicone tube and on the outer surface of the inner silicone tube. Finally, the nano BNC fibrils from two directions formed a BNC tube with good structural integrity. Scanning electron microscopy inspection showed that the tubular BNC had a multilayer structure in the beginning but finally it disappeared and an intact BNC tube formed. The mechanical properties of BNC tubes were comparable with the reported value in literatures, demonstrating a great potential in vascular implants or in functional substitutes in biomedicine.

Preliminary Study on Biosynthesis of Bacterial Nanocellulose Tubes in a Novel Double-Silicone-Tube Bioreactor for Potential Vascular Prosthesis.

Science.gov (United States)

Hong, Feng; Wei, Bin; Chen, Lin

2015-01-01

Bacterial nanocellulose (BNC) has demonstrated a tempting prospect for applications in substitute of small blood vessels. However, present technology is inefficient in production and BNC tubes have a layered structure that may bring danger after implanting. Double oxygen-permeable silicone tubes in different diameters were therefore used as a tube-shape mold and also as oxygenated supports to construct a novel bioreactor for production of the tubular BNC materials. Double cannula technology was used to produce tubular BNC via cultivations with Acetobacter xylinum, and Kombucha, a symbiosis of acetic acid bacteria and yeasts. The results indicated that Kombucha gave higher yield and productivity of BNC than A. xylinum. Bacterial nanocellulose was simultaneously synthesized both on the inner surface of the outer silicone tube and on the outer surface of the inner silicone tube. Finally, the nano BNC fibrils from two directions formed a BNC tube with good structural integrity. Scanning electron microscopy inspection showed that the tubular BNC had a multilayer structure in the beginning but finally it disappeared and an intact BNC tube formed. The mechanical properties of BNC tubes were comparable with the reported value in literatures, demonstrating a great potential in vascular implants or in functional substitutes in biomedicine.

Preliminary Study on Biosynthesis of Bacterial Nanocellulose Tubes in a Novel Double-Silicone-Tube Bioreactor for Potential Vascular Prosthesis

Science.gov (United States)

Wei, Bin; Chen, Lin

2015-01-01

Bacterial nanocellulose (BNC) has demonstrated a tempting prospect for applications in substitute of small blood vessels. However, present technology is inefficient in production and BNC tubes have a layered structure that may bring danger after implanting. Double oxygen-permeable silicone tubes in different diameters were therefore used as a tube-shape mold and also as oxygenated supports to construct a novel bioreactor for production of the tubular BNC materials. Double cannula technology was used to produce tubular BNC via cultivations with Acetobacter xylinum, and Kombucha, a symbiosis of acetic acid bacteria and yeasts. The results indicated that Kombucha gave higher yield and productivity of BNC than A. xylinum. Bacterial nanocellulose was simultaneously synthesized both on the inner surface of the outer silicone tube and on the outer surface of the inner silicone tube. Finally, the nano BNC fibrils from two directions formed a BNC tube with good structural integrity. Scanning electron microscopy inspection showed that the tubular BNC had a multilayer structure in the beginning but finally it disappeared and an intact BNC tube formed. The mechanical properties of BNC tubes were comparable with the reported value in literatures, demonstrating a great potential in vascular implants or in functional substitutes in biomedicine. PMID:26090420

Wolsong 3 and 4 steam generator tube inspection

International Nuclear Information System (INIS)

Jang, Kyoung Sik; Son, Tai Bong; Kwon, Dong Ki; Choi, Jin Hyuk

2001-01-01

During the pre-service inspection for Wolsong unit 3 and 4 in 1997/1998 respectively, 17 distorted roll transition indications (over expanded beyond tubesheet secondary face) were identified at the unit 4 (S/G B, D). Six(6) tubes out of these tubes were plugged in 1998. However the first periodic inspection identified additional 110 indications in 1999 and 2000. The additionally identified 110 indication call, not reported at the pre-service inspection, are; 2 not-finally-expanded-tubes and 108 distorted roll transition tubes. Design limit of each steam generator tube plugging is 6.4.%. Plugging was performed by the steam generator manufacturer under the warranty. When distorted roll transition indications were first identified on the unit 4 in 1998 the degree of over-expansion was measured using an inner dial-gage to make the disposition of nonconformance report. 2 Not-finally-expanded-tubes were plugged and 10 tubes out of 108 distorted roll transition tubes were also plugged as a preventive measure

Resonant oscillations in open axisymmetric tubes

Science.gov (United States)

Amundsen, D. E.; Mortell, M. P.; Seymour, B. R.

2017-12-01

We study the behaviour of the isentropic flow of a gas in both a straight tube of constant cross section and a cone, open at one end and forced at or near resonance at the other. A continuous transition between these configurations is provided through the introduction of a geometric parameter k associated with the opening angle of the cone where the tube corresponds to k=0. The primary objective is to find long-time resonant and near-resonant approximate solutions for the open tube, i.e. k→ 0. Detailed analysis for both the tube and cone in the limit of small forcing (O(ɛ 3)) is carried out, where ɛ 3 is the Mach number of the forcing function and the resulting flow has Mach number O(ɛ ). The resulting approximate solutions are compared with full numerical simulations. Interesting distinctions between the cone and the tube emerge. Depending on the damping and detuning, the responses for the tube are continuous and of O(ɛ ). In the case of the cone, the resonant response involves an amplification of the fundamental resonant mode, usually called the dominant first-mode approximation. However, higher modes must be included for the tube to account for the nonlinear generation of higher-order resonances. Bridging these distinct solution behaviours is a transition layer of O(ɛ 2) in k. It is found that an appropriately truncated set of modes provides the requisite modal approximation, again comparing well to numerical simulations.

Separately removable tubes in heavy duty heat exchanger assemblies

International Nuclear Information System (INIS)

Neudeck, G.T.

1980-01-01

The invention is directed to removable heat exchanger tube assemblies in heavy duty equipment radiators in which the tubes are each separately removable if they become defective in service. An inwardly facing annular ledge or abutment is molded into the inside diameter of each upper and lower sealing member to receive the respective ends of the tubes and prevent vertical movement of the tubes in service. A flange or shoulder is also provided on the lower portions of each tube and engages the inside of the lower sealing member to further restrain downward movement of the tubes in service. Each tube may be removed by pushing the tube upwardly to overcome the upper ledge abutment and thereby lift the tube free of the lower seal. Each tube may then be removed sidewise from the radiator. Variations of the removable sealing arrangement can be made and are described herein

Survival period after tube feeding in bedridden older patients.

Science.gov (United States)

Kosaka, Yoichi; Nakagawa-Satoh, Takuma; Ohrui, Takashi; Fujii, Masahiko; Arai, Hiroyuki; Sasaki, Hidetada

2012-04-01

We prospectively studied survival periods after tube feeding. Participants were 163 bedridden older patients suffering from dysphagia. A wide range of survival periods after tube feeding were observed within half a year without tube feeding after being bedridden. After this initial period, survival periods after tube feeding were limited to approximately half a year. Survival periods after tube feeding were positively proportional to the length of time patients were free from pneumonia after tube feeding. After tube feeding, patients died from pneumonia within half a year, and the frequency of pneumonia was 3.1 ± 2.7 times (mean ± SD) before death. Survival periods after tube feeding for less than 1 year were primarily determined by being bedridden for more than half a year without tube feeding and once pneumonia occurred; patients who were tube fed did not survive for more than half a year. © 2012 Japan Geriatrics Society.

The Functionality of Paratexts on YouTube

DEFF Research Database (Denmark)

Simonsen, Thomas Mosebo

2014-01-01

This chapter investigates paratexts and their functionality on YouTube. It is argued that YouTube content is in fact characterized by its dependence and usage of paratexts as part of YouTube's infrastructure. Paratexts are presented as being either auto-generated by YouTube or created by its users....... They are furthermore identified through a distinction between spatial and temporal relationships. Based on these distinctions, a small survey of some of the most popular videos on YouTube is conducted in order to examine the appearance and functionality of paratexts. A principal argument of the chapter...... is that the functionality of the paratexts can be explained by what Genette characterizes as the paratext's illocutionary force, which is examined in relationship to YouTube's paratexts and, more specifically, the site's implementation of links. The chapter also argues that paratexts may be characterized as a necessary...

Process for installing tubes in a steam generator

International Nuclear Information System (INIS)

Boula, G.; George, A.

1988-01-01

This process consists essentially to introduce the tubes by planar layers, to place antivibration bars above the layer and tensioning the bars with forces perpendicular to the layer, to check the play between the bars and the tubes and to replace the tubes beyond tolerance by other tubes [fr

21 CFR 870.4390 - Cardiopulmonary bypass pump tubing.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump tubing. 870.4390 Section 870.4390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass pump tubing. (a) Identification. A cardiopulmonary bypass pump tubing is polymeric tubing which is...

Support tube of in-core instruments

International Nuclear Information System (INIS)

Suzumura, Takeshi; Saito, Shozo; Yasuda, Tetsuo; Shirosaki, Kiyotaka.

1975-01-01

Object: To permit satisfactory output measurement by preventing the bending of a in-core instrument tube within a reactor due to vibrations by means of a spring and thereby preventing mechanical damage of an adjacent fuel channel box. Structure: At a corner of a channel box of a fuel assembly, a in-core instrument tube is arranged along a channel box and has its surface provided with a plurality of removable leaf springs arranged in the direction of axis of the in-core instrument tube and each having an arcular tip. Thus, when the in-core instrument tube is inserted into the reactor, the arcular tip portions of the leaf springs are brought into plane contact with the corner of the channel box so that the in-core instrument tube is elastically supported on the channel box. Thus, there is no possibility of causing damage to the adjacent fuel channel box. (Kamimura, M.)

Management of chest drainage tubes after lung surgery.

Science.gov (United States)

Satoh, Yukitoshi

2016-06-01

Since chest tubes have been routinely used to drain the pleural space, particularly after lung surgery, the management of chest tubes is considered to be essential for the thoracic surgeon. The pleural drainage system requires effective drainage, suction, and water-sealing. Another key point of chest tube management is that a water seal is considered to be superior to suction for most air leaks. Nowadays, the most common pleural drainage device attached to the chest tube is the three-bottle system. An electronic chest drainage system has been developed that is effective in standardizing the postoperative management of chest tubes. More liberal use of digital drainage devices in the postoperative management of the pleural space is warranted. The removal of chest tubes is a common procedure occurring almost daily in hospitals throughout the world. Extraction of the tube is usually done at the end of full inspiration or at the end of full expiration. The tube removal technique is not as important as how it is done and the preparation for the procedure. The management of chest tubes must be based on careful observation, the patient's characteristics, and the operative procedures that had been performed.

Safety significance of steam generator tube degradation mechanisms

Energy Technology Data Exchange (ETDEWEB)

Roussel, G; Mignot, P [AIB-Vincotte Nuclear - AVN, Brussels (Belgium)

1991-07-01

Steam generator (SG) tube bundle is a part of the Reactor Coolant Pressure Boundary (RCPB): this means that its integrity must be maintained. However, operating experience shows various types of tube degradation to occur in the SG tubing, which may lead to SG tube leaks or SG tube ruptures and create a loss of primary system coolant through the SG, therefore providing a direct path to the environment outside the primary containment structure. In this paper, the major types of known SG tube degradations are described and analyzed in order to assess their safety significance with regard to SG tube integrity. In conclusion: The operational reliability and the safety of the PWR steam generator s requires a sufficient knowledge of the degradation mechanisms to determine the amount of degradation that a tube can withstand and the time that it may remain in operation. They also require the availability of inspection techniques to accurately detect and characterize the various degradations. The status of understanding of the major types of degradation summarized in this paper shows and justifies why efforts are being performed to improve the management of the steam generator tube defects.

X-ray tube technology update

International Nuclear Information System (INIS)

Rehani, M.M.

1997-01-01

During the 100 years since the discovery of x-rays, the x-ray tube has undergone significant improvements to meet the demand of shorter exposure time and frequent exposures as in angiography. This has been achieved by multiple focal spots, rotating anodes, design consideration of the anode and the tube assembly. While physical improvements have resulted in improved performance, the principle has remained the same, as also has the problem of massive heat generation which consumes almost 99% of the energy. This article traces the history of tubes and current perspectives. (author). 3 refs., 3 figs., 2 tabs

Development of a discharge-heated plasma tube

International Nuclear Information System (INIS)

Cha, Byung Heon; Jin, J. T.; Nam, S. M.; Lee, S. M.; Choi, H. L.; Ko, D. K.; Kim, S. H.; Lee, Y. B.; Choi, Y. S.; Lee, J. M.; Lee, C. K.; Lee, H. G.; Lee, H. C.; Jung, S. M.; Kim, Y. J.; Choi, G. S.; Son, N. G.

1999-12-01

A discharge-heated type plasma tube was designed and constructed. The structure of the laser plasma tube was designed to be easy in maintenance. The inside plasma tube was made of a high purity alumina and the thermal insulator tube was made of a porous alumina. The electrode made of tungsten was chosen for the endurance of high discharge voltage. AR coated windows were used as laser windows. A proto-type laser plasma tube was tested with a pulse modulator. An average laser output power was 32 W at the discharge voltage of 28 kV, the electric input power of 4.6 kW, and the pulse repetition rates of 10 kHz. (author)

Single chest tube drainage is superior to double chest tube drainage after lobectomy: a meta-analysis.

Science.gov (United States)

Zhou, Dong; Deng, Xu-Feng; Liu, Quan-Xing; Chen, Qian; Min, Jia-Xin; Dai, Ji-Gang

2016-05-27

In this meta-analysis, we conducted a pooled analysis of clinical studies comparing the efficacy of single chest tube versus double chest tube after a lobectomy. According to the recommendations of the Cochrane Collaboration, we established a rigorous study protocol. We performed a systematic electronic search of the PubMed, Embase, Cochrane Library and Web of Science databases to identify articles to include in our meta-analysis. A literature search was performed using relevant keywords. A meta-analysis was performed using RevMan© software. Five studies, published between 2003 and 2014, including 630 patients (314 patients with a single chest tube and 316 patients with a double chest tube), met the selection criteria. From the available data, the patients using a single tube demonstrated significantly decreased postoperative pain [weighted mean difference [WMD] -0.60; 95 % confidence intervals [CIs] -0.68-- 0.52; P tube after a pulmonary lobectomy. However, there were no significant differences in postoperative complications [OR 0.91; 95 % CIs 0.57-1.44; P = 0.67] and re-drainage rates [OR 0.81; 95 % CIs 0.42-1.58; P = 0.54]. Our results showed that a single-drain method is effective, reducing postoperative pain, hospitalization times and duration of drainage in patients who undergo a lobectomy. Moreover, the single-drain method does not increase the occurrence of postoperative complications and re-drainage rates.

Development of Zirconium alloys (for pressure tubes)

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Suk; Kwon, Sang Chul; Choo, Ki Nam; Jung, Chung Hwan; Yim, Kyong Soo; Kim, Sung Soo; Baek, Jong Hyuk; Jeong, Yong Hwan; Kim, Kyong Ho; Cho, Hae Dong [Korea Atomic Energy Research Inst., Daeduk (Korea, Republic of); Hwang, S. K.; Kim, M. H. [Inha Univ., Incheon (Korea, Republic of); Kwon, S. I [Korea Univ., Seoul (Korea, Republic of); Kim, I. S. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of)

1997-09-01

The objective of this research is to set up the basic technologies for the evaluation of pressure tube integrity and to develop improved zirconium alloys to prevent pressure tube failures due to DHC and hydride blister caused by excessive creep-down of pressure tubes. The experimental procedure and facilities for characterization of pressure tubes were developed. The basic research related to a better understanding of the in-reactor performances of pressure tubes leads to noticeable findings for the first time : the microstructural effect on corrosion and hydrogen pick-up behavior of Zr-2.5Nb pressure tubes, texture effect on strength and DHC resistance and enhanced recrystallization by Fe in zirconium alloys and etc. Analytical methodology for the assessment of pressure tubes with surface flaws was set up. A joint research is being under way with AECL to determine the fracture toughness of O-8 at the EOL (End of Life) that had been quadruple melted and was taken out of the Wolsung Unit-1 after 10 year operation. In addition, pressure tube with texture controlled is being made along with VNINM in Russia as a joint project between KAERI and Russia. Finally, we succeeded in developing 4 different kinds of zirconium alloys with better corrosion resistance, low hydrogen pickup fraction and higher creep strength. (author). 121 refs., 65 tabs., 260 figs

Emergency transfer tube closure and process for sealing transfer tube under emergency conditions

International Nuclear Information System (INIS)

Hardin, R.T. Jr.; Marshall, J.R.

1987-01-01

In a nuclear fuel reactor well that includes a transfer tube projecting outwardly from wall thereof, the transfer tube is described having a first closure assembly. The transfer tube has a circumferential flange extending outwardly laterally therefrom, an emergency transfer tube closure therefor comprising; a pair of elongated, vertically-extending U-shaped guides, one U-shaped guide disposed laterally on each side of the transfer tube, each of the U-shaped guides comprising a base and laterally extending flanges thereon, the U-shaped guides having their open ends facing each other, a closure plate, having a surface facing the circumferential flange greater in area than the area circumscribed by the outer circumference of the circumferential flange, vertically disposed the U-shaped guides, the closure plate normally being disposed in a vertical plane just slightly in front of the vertical plane of the circumferential flange, two pairs of rollers, one pair of which is rotatably mounted on each side of the closure plate adjacent the U-shaped guides, riding on the inner portion of each of the flanges of each of the U-shaped guides. Each of the U-shaped guides is provided with a pair of spatially disposed openings on a flange thereof adjacent the wall of the nuclear fuel reactor well, each of the pairs of openings being disposed on each of the U-shaped guides a distance equal to the distance between the center lines of the corresponding pair of rollers riding within the U-shaped guides, each of the openings being sufficiently large to receive a corresponding roller of the pairs of rollers in the U-shaped guides. The openings is shaped on the flanges of the U-shaped guides so that when the pairs of rollers are disposed therein, the face of the closure plate will be in sealing engagement with the circumferential flange of the transfer tube

Integrity Assessment of GOH Heater Tube

Energy Technology Data Exchange (ETDEWEB)

Lee, Bong Sang; Hong, J. H.; Oh, Y. J.; Yoon, J. H.; Oh, J. M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1997-08-01

An assessment of structural integrity of ASTM A312-TP347 GOH heater tube was performed. The surface notches which had been produced during tube manufacturing process were analyzed microscopically. Chemical analysis, hardness tests, tensile tests, and J-Integral fracture resistance tests were carried out to compare the mechanical properties with those of the material specification and also with the other material of the same type. The test results showed the mechanical properties of the GOH tube material are within the specification range. An elastic-plastic fracture mechanics analysis based on the DPFAD method reveals the tube an appropriate safety margin for the normal operation. 13 refs., 5 tabs., 24 figs. (author)

The nasogastric tube syndrome in infants.

Science.gov (United States)

Harmon, Jeffrey; Balakrishnan, Karthik; de Alarcon, Alessandro; Hart, Catherine K

2014-05-01

This series of three patients is the first description of the presentation, clinical course, and endoscopic findings of nasogastric tube-related airway distress, or nasogastric tube syndrome, in infants. We identify key differences in disease features from those described in adults, based on our literature review. Specifically, infant nasogastric tube syndrome presented as significant respiratory distress and postcricoid inflammation without vocal fold immobility. Symptoms resolved more quickly (mean±SD, 2±1 days) than reported in adults. We suggest that nasogastric tube syndrome should be considered in infants with otherwise unexplained respiratory distress, even in the absence of impaired vocal fold mobility. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

NMDA Receptor Signaling Is Important for Neural Tube Formation and for Preventing Antiepileptic Drug-Induced Neural Tube Defects.

Science.gov (United States)

Sequerra, Eduardo B; Goyal, Raman; Castro, Patricio A; Levin, Jacqueline B; Borodinsky, Laura N

2018-05-16

Failure of neural tube closure leads to neural tube defects (NTDs), which can have serious neurological consequences or be lethal. Use of antiepileptic drugs (AEDs) during pregnancy increases the incidence of NTDs in offspring by unknown mechanisms. Here we show that during Xenopus laevis neural tube formation, neural plate cells exhibit spontaneous calcium dynamics that are partially mediated by glutamate signaling. We demonstrate that NMDA receptors are important for the formation of the neural tube and that the loss of their function induces an increase in neural plate cell proliferation and impairs neural cell migration, which result in NTDs. We present evidence that the AED valproic acid perturbs glutamate signaling, leading to NTDs that are rescued with varied efficacy by preventing DNA synthesis, activating NMDA receptors, or recruiting the NMDA receptor target ERK1/2. These findings may prompt mechanistic identification of AEDs that do not interfere with neural tube formation. SIGNIFICANCE STATEMENT Neural tube defects are one of the most common birth defects. Clinical investigations have determined that the use of antiepileptic drugs during pregnancy increases the incidence of these defects in the offspring by unknown mechanisms. This study discovers that glutamate signaling regulates neural plate cell proliferation and oriented migration and is necessary for neural tube formation. We demonstrate that the widely used antiepileptic drug valproic acid interferes with glutamate signaling and consequently induces neural tube defects, challenging the current hypotheses arguing that they are side effects of this antiepileptic drug that cause the increased incidence of these defects. Understanding the mechanisms of neurotransmitter signaling during neural tube formation may contribute to the identification and development of antiepileptic drugs that are safer during pregnancy. Copyright © 2018 the authors 0270-6474/18/384762-12$15.00/0.

The Tube on YouTube: TV Series, Media Strategies, and User Tactics in a Transmedia Environment

OpenAIRE

Rodríguez Ferrándiz, Raúl; Tur-Viñes, Victoria; Mora Contreras, Francisco Javier

2015-01-01

This study analyzes the traffic generated on YouTube around television series. We selected a sample of 314 short YouTube videos about 21 Spanish TV series that premiered in 2013 by Spain’s three most popular mainstream television networks (Telecinco, Antena 3, and La1). These videos, which together received more than 24 million views, were classified according to two key variables: the nature (official or nonofficial) of the YouTube channel on which they were located and the exclusivity of th...

30 CFR 250.517 - Tubing and wellhead equipment.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Tubing and wellhead equipment. 250.517 Section... Tubing and wellhead equipment. (a) No tubing string shall be placed in service or continue to be used unless such tubing string has the necessary strength and pressure integrity and is otherwise suitable for...

Conservatism in methodologies for moderator subcooling sufficiency for fuel channel integrity upon pressure tube and calandria tube contact

Energy Technology Data Exchange (ETDEWEB)

Sun, L., E-mail: LSun@nbpower.com [Point Lepreau Generating Station, Lepreau, NB, (Canada)

2015-07-01

During a postulated large LOCA event in CANDU reactors, the pressure tube may balloon to contact with its surrounding calandria tube to transfer heat to the moderator. To confirm the integrity of the fuel channel in this case, many experiments have been performed in the last three decades. Based on the extant database of the pressure tube/calandria tube (PT/CT) contact, an analytical methodology was developed by Canadian Nuclear Industry to determine the sufficiency of moderator subcooling for fuel channel integrity. At the same time a semi-empirical methodology with an idea of Equivalent Moderator Subcooling (EMS) was also developed to judge the sufficiency of the moderator. In this work, some discussions were made over the two methodologies on their conservatism and it is demonstrated that the analytical approach is over conservative comparing with the EMS methodology. By using the EMS methodology, it is demonstrated that applying glass-peened calandria tubes, the requirement to moderator subcooling can be reduced by 10{sup o}C from that for smooth calandria tubes. (author)

Dimensional Measurements of Three Tubes by Computed Tomography

International Nuclear Information System (INIS)

Schneberk, D.J.; Martz, H.E. Jr.; Brown, W.D.

2004-01-01

Low density polyethylene (LDPE), copper (Cu), and gold (Au) tubes were scanned on KCAT to identify and evaluate the impact of phase effects on quantitative object recovery. These tubes are phantoms for high energy density capsules.[Logan, et al. 2004] Digital radiographs for each tube are shown in Figure 1. The LDPE tube was scanned at 60 kV, while the Cu and the Au tubes were scanned at 140 kV. All tubes were scanned at a magnification of 3, with approximately 100-mm distance between the exit plane of the tube and the scintillator. Notice the prominence of the outer bright and inner dark edges for the LDPE tube DR, and their absence from the Cu and Au tube DRs. The bright and dark edges are a result of change in phase of the x-rays. The x-ray fluence is partly attenuated and partly refracted. The location near the outer edge of the tube appears to be more attenuating since those x-rays have refracted to locations just outside the tube. Alternatively, the added counts from the refraction result in intensities that are greater than the incident intensity effectively representing a ''negative attenuation''. This results in more counts in that location than in the incident intensity image violating the ''positive-definite'' requirement for standard CT reconstruction methodologies. One aspect of our CT processing techniques remove some of this signal on the outside of the object. The goal of this paper is to evaluate the accuracy of our dimensional measurement methods for mesoscale object inspection

Precision alignment of permanent-magnet drift tubes

International Nuclear Information System (INIS)

Liska, D.J.; Dauelsberg, L.B.; Spalek, G.

1986-01-01

The Lawrence Berkeley National Laboratory (LBNL) technique of drift-tube alignment has been resurrected at Los Alamos for the precision alignment of 1-cm-bore drift tubes that carry high-gradient rare-earth-cobalt quadrupole. Because the quadrupole cannot be switched off, this technique is not applicable to a drift-tube assembly, but tests indicate that individual magnetic centers can be detected with a precision of +- 0.003 mm. Methods of transferring this information to machined alignment flats on the sides of the drift-tube body are discussed. With measurements of drift tubes designed for a 100-mA. 425-MHz drift-tube linac, we have detected offsets between the geometric and magnetic axes of up to +- 0.05 mm following final assembly and welding. This degree of offset is serious if not accommodated, because it represents the entire alignment tolerance for the 40-cell tank. The measurement equipment and technique are described

Autologous patch graft in tube shunt surgery.

Science.gov (United States)

Aslanides, I M; Spaeth, G L; Schmidt, C M; Lanzl, I M; Gandham, S B

1999-10-01

To evaluate an alternate method of covering the subconjunctival portion of the tube in aqueous shunt surgery. Evidence of tube erosion, graft-related infection, graft melting, or other associated intraocular complications were evaluated. A retrospective study of 16 patients (17 eyes) who underwent tube shunt surgery at Wills Eye Hospital between July 1991 and October 1996 was conducted. An autologous either "free" or "rotating" scleral lamellar graft was created to cover the subconjunctival portion of the tube shunt. All patients were evaluated for at least 6 months, with a mean follow-up of 14.8 months (range 6-62 months). All eyes tolerated the autologous graft well, with no clinical evidence of tube erosion, or graft-related or intraocular complications. Autologous patch graft in tube shunt surgery appears--in selected cases--to be an effective, safe and inexpensive surgical alternative to allogenic graft materials. It also offers ease of availability, and eliminates the risk of transmitting infectious disease.

Radiant absorption characteristics of corrugated curved tubes

Directory of Open Access Journals (Sweden)

Đorđević Milan Lj.

2017-01-01

Full Text Available The utilization of modern paraboloidal concentrators for conversion of solar radiation into heat energy requires the development and implementation of compact and efficient heat absorbers. Accurate estimation of geometry influence on absorption characteristics of receiver tubes is an important step in this process. This paper deals with absorption characteristics of heat absorber made of spirally coiled tubes with transverse circular corrugations. Detailed 3-D surface-to-surface Hemicube method was applied to compare radiation performances of corrugated and smooth curved tubes. The numerical results were obtained by varying the tube curvature ratio and incident radiant heat flux intensity. The details of absorption efficiency of corrugated tubes and the effect of curvature on absorption properties for both corrugated and smooth tubes were presented. The results may have significance to further analysis of highly efficient heat absorbers exposed to concentrated radiant heating. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 42006

Guide tube sleeve

International Nuclear Information System (INIS)

Attix, D.J.

1983-01-01

The invention increases the operating capacity of a nuclear reactor by causing a modification in the flow pattern of the coolant which enhances the coolant's effectiveness. The apparatus provides a thin-walled tubular sleeve closely surrounding but not attached to the exterior surface of a guide tube in a fuel assembly. The wall of the sleeve has tabs projecting outwardly into adjacent flow channels. The sleeve is attached to the wall of a cellular void through which passes the guide tube associated with said sleeve. The tabs increase the flow of water in the channel and thus increase the heat transfer

The single chest tube versus double chest tube application after pulmonary lobectomy: A systematic review and meta-analysis

Directory of Open Access Journals (Sweden)

Xuefei Zhang

2016-01-01

Conclusion: Compared with the double chest tube, the single chest tube significantly decreases amount of drainage, duration of chest tube drainage, pain score, the number of patients who need thoracentesis, and cost. Although there is convincing evidence to confirm the results mentioned herein, they still need to be confirmed by large-sample, multicenter, randomized, controlled trials.

Percutaneous transesophageal gastro-tubing (PTEG) as an alternative long-term tube feeding procedure when gastrostomy is not feasible.

Science.gov (United States)

Toh Yoon, Ezekiel Wong; Nishihara, Kazuki

2017-12-01

Percutaneous transesophageal gastro-tubing (PTEG) is a minimally invasive technique to access the gut via an esophagostomy. However, this procedure is not well known and the literature available is still fairly limited. This observational study was conducted to evaluate our experience using this method as an alternative long-term tube feeding procedure when gastrostomy is not suitable. A total of 15 patients (10 males and 5 females) who underwent PTEG at our institution from 2012 to 2016 were observed and analyzed in this study. The average age was 80.1 (71-93) years. Underlying conditions that required PTEG were previous gastric resection in 11 patients, left diaphragm disorder in 2 patients, interposing transverse colon between the abdominal wall and anterior gastric wall in 1 patient, and severe gastrostomy site leakage in 1 patient. Tube placement was successful in all patients by approaching the left side of the neck, using a 15 Fr size tube. The mean postoperative length of stay was 22 (8-48) days. Postoperative adverse events included accidental tube dislodgement in three patients, tracheoesophageal fistula in one patient, inferior thyroid artery injury in one patient and thyroid gland mispuncture in one patient. There was no procedure-related mortality nor mortality at 30 days. Eight patients were discharged with some oral intake. PTEG is feasible in patients requiring long-term tube feeding for whom gastrostomy is unsuitable. It is an effective long-term tube feeding procedure and should be offered as a more comfortable alternative to nasogastric tubing.

Preparation of nitrogen-doped carbon tubes

Science.gov (United States)

Chung, Hoon Taek; Zelenay, Piotr

2015-12-22

A method for synthesizing nitrogen-doped carbon tubes involves preparing a solution of cyanamide and a suitable transition metal-containing salt in a solvent, evaporating the solvent to form a solid, and pyrolyzing the solid under an inert atmosphere under conditions suitable for the production of nitrogen-doped carbon tubes from the solid. Pyrolyzing for a shorter period of time followed by rapid cooling resulted in a tubes with a narrower average diameter.

WWER Steam Generators Tubing Performance and Aging Management

International Nuclear Information System (INIS)

Trunov, Nikolay B.; Davidenko, Stanislav E.; Grigoriev, Vladimir A.; Popadchuk, Valery S.; Brykov, Sergery I.; Karzov, Georgy P.

2006-01-01

At WWER NPPs the horizontal steam generators (SGs), are used that differ in design concept from vertical SGs mostly used at western NPPs. Reliable operation of SG heat-exchanging tubes is the crucial worldwide problem for NPP of various types. According to the operation feedback the water chemistry is the governing factor affecting operability of SG tubing. The secondary side corrosion is considered to be the main mechanism of SG heat-exchanging tubes damage at WWER plants. To make the assessment of the tubing integrity the combination of pressure tests and eddy-current tests is used. Assessment of the tubing performance is an important part of SG life extension practice. The given paper deals with the description of the tube testing strategy and the approach to tube integrity assessment based on deterministic and probabilistic methods of fracture mechanics. Requirements for eddy-current test are given as well. Practice of condition monitoring and implementing the database on steam generators operation are presented. The approach to tubes plugging criteria is described. The research activities on corrosion mechanism studies and residual lifetime evaluation are mentioned. (authors)

Virtual Community Based Destination Marketing with YouTube

DEFF Research Database (Denmark)

Sambhanthan, Arunasalam; Thelijjagoda, Samantha; Good, Alice

2016-01-01

YouTube has now evolved into a powerful medium for social interaction. Utilizing YouTube for enhancing marketing endeavours is a strategy practiced by marketing professionals across several industries. This paper rationalizes on the different strategies of leveraging YouTube-based platforms...... for effective destination marketing by the hospitality industry (hotels) and provides insights on the critical drivers and challenges embedded within YouTube-based community interactions for destination marketing. The comments made by YouTube users have been subjected to a content analysis and the results...... are reported under the five broad clusters of virtual communities. More broadly, the typology of virtual communities is adapted to evaluate the YouTube platform for effective destination marketing....

Failure analysis of the boiler water-wall tube

Directory of Open Access Journals (Sweden)

S.W. Liu

2017-10-01

Full Text Available Failure analysis of the boiler water-wall tube is presented in this work. In order to examine the causes of failure, various techniques including visual inspection, chemical analysis, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were carried out. Tube wall thickness measurements were performed on the ruptured tube. The fire-facing side of the tube was observed to have experienced significant wall thinning. The composition of the matrix material of the tube meets the requirements of the relevant standards. Microscopic examinations showed that the spheroidization of pearlite is not very obvious. The failure mechanism is identified as a result of the significant localized wall thinning of the boiler water-wall tube due to oxidation.

Slip of the T tube within the common bile duct: A little known complication of the T tube drainage

Directory of Open Access Journals (Sweden)

Čolović Radoje

2005-01-01

Full Text Available Complications related to the T tube drainage of the common bile duct are not uncommon. Some, like dislocations of the T tube out of the common bile duct, could be very serious, particularly if developed during the first few days after surgery, when the abdominal drain in the subhepatic space had been already removed. Then, an emergency reoperation might be necessary. The slip of the T tube upwards or downwards inside the common bile duct is not so rare. Fortunately, it is less dangerous and can usually be resolved without reoperation. It takes place several days after surgery, followed by the right subcostal pain, occasionally with temperature, rise of the bilirubin and with decrease or complete cessation of the bile drainage through the T tube. The diagnosis can be made only on the basis of T tube cholangiography. The re-establishment of the proper T tube position must be done under X-ray visualization. Seven cases of the T tube slip within the common bile duct, its clinical presentation, diagnosis and method of repositioning were presented. Possible mechanism of complication was described. As far as we know, the complications have not been described by other authors.

Laparoscopic insertion of the Moss feeding tube.

Science.gov (United States)

Albrink, M H; Hagan, K; Rosemurgy, A S

1993-12-01

Placement of enteral feeding tubes is an important part of a surgeon's skill base. Surgical insertion of feeding tubes has been performed safely for many years with very few modifications. With the recent surge in interest and applicability of other laparoscopic procedures, it is well within the skills of the average laparoscopic surgeon to insert feeding tubes. We describe herein a simple technique for the insertion of the Moss feeding tube. The procedure described has a minimum of invasion, along with simplicity, safety, and accuracy.

Selected reading on introduction to pressure tube technology

International Nuclear Information System (INIS)

Causey, A.R.; Coleman, C.E.; Ells, C.E.

1981-10-01

Four lectures on pressure tube technology were presented at Sheridan Park, Ontario, on 1981 June 1. The titles were 'Pressure Tubes and Their Operational Environment', 'Fabrication, Inspection and Properties of Current Production Pressure Tubes', 'In-Reactor Deformation of Fuel Channels', and 'Potential Failure Modes in Pressure Tubes'. This report lists the references used in preparing the lectures. It is intended to provide a starting point in reading for people who need to become familiar with pressure tube technology but have little prior knowledge of the topic

Advanced evacuated tube collectors

Science.gov (United States)

Schertz, W. W.; Hull, J. R.; Winston, R.; Ogallagher, J.

1985-04-01

The essence of the design concept for these new collectors is the integration of moderate levels of nonimaging concentration inside the evacuated tube itself. This permanently protects the reflection surfaces and allows the use of highly reflecting front surface mirrors with reflectances greater than 95%. Previous fabrication and long term testing of a proof-of-concept prototype has established the technical success of the concept. Present work is directed toward the development of a manufacturable unit that will be suitable for the widest possible range of applications. Design alternatives include scaling up the original prototype's tube diameter from 5 cm to 10 cm, using an internal shaped metal concentrating reflector, using a variety of profile shapes to minimize so-called gap losses and accommodate both single ended and double-ended flow geometries, and allowing the use of heat pipes for the absorber tube.

Vibration and wear characteristics of steam generator tubes

International Nuclear Information System (INIS)

Choi, Young Hwan

2003-06-01

This study investigates the fluid elastic instability characteristics of Steam Generator (SG) U-tubes with defect and the safety assessment of the potential for fretting-wear damages on Steam Generator (SG) U-tubes caused by foreign object in operating nuclear power plants. The operating SG shell-side flow field conditions for determining the fluid elastic instability or fretting-wear parameters such as damping ratio, added mass and flow velocity are obtained from three-dimensional SG flow calculation using the ATHOS3 code. To get the natural frequency, corresponding mode shape and participation factor, modal analyses are performed for the U-tubes either with axial or circumferential flaw with different sizes. Special emphases are on the effects of flaw orientation and size on the modal and instability characteristics of tubes, which are expressed in terms of the natural frequency, corresponding mode shape and stability ratio. Also, the wear rate of U-tube caused by foreign object is calculated using the Archard formula and the remaining life of the tube is predicted, and discussed in this study is the effect of the flow velocity and vibration of the tube on the remaining life of the tube. In addition, addressed is the effect of the internal pressure on the vibration and fretting-wear characteristics of the tube

Set-up for steam generator tube bundle washing after explosion expanding the tubes

International Nuclear Information System (INIS)

Osipov, S.I.; Kal'nin, A.Ya.; Mazanenko, M.F.

1985-01-01

Set-up for steam generator tube bundle washing after the explosion expanding of tubes is described. Washing is accomplished by distillate. Steam is added to distillate for heating, and compersed air for preventing hydraulic shock. The set-up is equiped by control equipment. Set-up performances are presented. Time for one steam generator washing constitutes 8-12 h. High economic efficiency is realized due to the set-up introduction

Feeding Tubes

Science.gov (United States)

... feeding therapies have been exhausted. Please review product brand and method of placement carefully with your physician ... Total Parenteral Nutrition. Resources: Oley Foundation Feeding Tube Awareness Foundation Children’s Medical Nutrition Alliance APFED’s Educational Webinar ...

Optimizing the Thermoacoustic Pulse Tube Refrigerator Performances

Directory of Open Access Journals (Sweden)

E. V. Blagin

2014-01-01

Full Text Available The article deals with research and optimization of the thermoacoustic pulse tube refrigerator to reach a cryogenic temperature level. The refrigerator is considered as a thermoacoustic converter based on the modified Stirling cycle with helium working fluid. A sound pressure generator runs as a compressor. Plant model comprises an inner heat exchanger, a regenerative heat exchanger, a pulse tube, hot and cold heat exchangers at its ends, an inertial tube with the throttle, and a reservoir. A model to calculate the pulse tube thermoacoustic refrigerator using the DeltaEC software package has been developed to be a basis for calculation techniques of the pulse tube refrigerator. Momentum, continuity, and energy equations for helium refrigerant are solved according to calculation algorithm taking into account the porosity of regenerator and heat exchangers. Optimization of the main geometric parameters resulted in decreasing temperature of cold heat exchanger by 41,7 K. After optimization this value became equal to 115,01 K. The following parameters have been optimized: diameters of the feeding and pulse tube and heat exchangers, regenerator, lengths of the regenerator and pulse and inertial tubes, as well as initial pressure. Besides, global minimum of temperatures has been searched at a point of local minima corresponding to the optimal values of abovementioned parameters. A global-local minima difference is 0,1%. Optimized geometric and working parameters of the thermoacoustic pulse tube refrigerator are presented.

Thermodynamic analysis of a pulse tube engine

International Nuclear Information System (INIS)

Moldenhauer, Stefan; Thess, André; Holtmann, Christoph; Fernández-Aballí, Carlos

2013-01-01

Highlights: ► Numerical model of the pulse tube engine process. ► Proof that the heat transfer in the pulse tube is out of phase with the gas velocity. ► Proof that a free piston operation is possible. ► Clarifying the thermodynamic working principle of the pulse tube engine. ► Studying the influence of design parameters on the engine performance. - Abstract: The pulse tube engine is an innovative simple heat engine based on the pulse tube process used in cryogenic cooling applications. The working principle involves the conversion of applied heat energy into mechanical power, thereby enabling it to be used for electrical power generation. Furthermore, this device offers an opportunity for its wide use in energy harvesting and waste heat recovery. A numerical model has been developed to study the thermodynamic cycle and thereby help to design an experimental engine. Using the object-oriented modeling language Modelica, the engine was divided into components on which the conservation equations for mass, momentum and energy were applied. These components were linked via exchanged mass and enthalpy. The resulting differential equations for the thermodynamic properties were integrated numerically. The model was validated using the measured performance of a pulse tube engine. The transient behavior of the pulse tube engine’s underlying thermodynamic properties could be evaluated and studied under different operating conditions. The model was used to explore the pulse tube engine process and investigate the influence of design parameters.

Patient identification and tube labelling

DEFF Research Database (Denmark)

van Dongen-Lases, Edmée C; Cornes, Michael P; Grankvist, Kjell

2016-01-01

of phlebotomy procedures with the CLSI H3-A6 guideline was unacceptably low, and that patient identification and tube labelling are amongst the most critical steps in need of immediate attention and improvement. The process of patient identification and tube labelling is an essential safety barrier to prevent...... patient identity mix-up. Therefore, the EFLM Working Group aims to encourage and support worldwide harmonisation of patient identification and tube labelling procedures in order to reduce the risk of preanalytical errors and improve patient safety. With this Position paper we wish to raise awareness...... and provide recommendations for proper patient and sample identification procedures....

PEG tubes: dealing with complications.

Science.gov (United States)

Malhi, Hardip; Thompson, Rosie

A percutaneous endoscopic gastronomy tube can be used to deliver nutrition, hydration and medicines directly into the patient's stomach. Patients will require a tube if they are unable to swallow safely, putting them at risk of aspiration of food, drink and medicines into their lungs. It is vital that nurses are aware of the complications that may arise when caring for a patient with a PEG tube. It is equally important that nurses know how to deal with these complications or from where tc seek advice. This article provides a quick troubleshooting guide to help nurses deal with complications that can arise with PEG feeding.

Applications of liquid scintillation tubes

International Nuclear Information System (INIS)

Broga, D.W.

1977-01-01

A new cocktail containing device for liquid scintillation counting, the scintillation tube, consists of a two-layered plastic bag which is heatsealed after the cocktail and sample have been placed in it. It is then placed in a carrying vial and counted in a conventional liquid scintillation counter. These tubes have proved to be a practical and economical alternative to vials. Some of their advantages are elimination of absorption problems, transparency, lower background and higher counting efficiency, low breakage danger and savings in waste disposal costs. Two applications for which the tubes are particularly suitable are the counting of laboratory swipes and urine analysis. (author)

Performance of a tapered pulse tube

International Nuclear Information System (INIS)

Swift, G.; Allen, M.; Woolan, J.J.

1998-02-01

In a well instrumented pulse tube refrigerator having 1,500 W of cooling power at 125 K, the authors have measured the figure of merit of a tapered pulse tube at several operating points. At operating points near the operating point for which the taper was designed, the figure of merit is 0.96. This is close to the theoretical optimum figure of merit 0.97 calculated for this pulse tube considering only two loss mechanisms: heat conduction in the metal pulse tube wall and ordinary thermoacoustic heat transport in the gas within a few thermal penetration depths of the wall. At operating points farther from the design operating point, the measured figure of merit is much lower, as streaming driven convection adds a third loss mechanism

NEI You Tube Videos: Amblyopia

Medline Plus

Full Text Available ... Amaurosis Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia NEI Home Contact Us A-Z Site Map NEI on Social Media Information in Spanish (Información en español) Website, ...

dc-plasma-sprayed electronic-tube device

Science.gov (United States)

Meek, T.T.

1982-01-29

An electronic tube and associated circuitry which is produced by dc plasma arc spraying techniques is described. The process is carried out in a single step automated process whereby both active and passive devices are produced at very low cost. The circuitry is extremely reliable and is capable of functioning in both high radiation and high temperature environments. The size of the electronic tubes produced are more than an order of magnitude smaller than conventional electronic tubes.

DEVELOPMENT OF COILED TUBING STRESS ANALYSIS

Directory of Open Access Journals (Sweden)

Davorin Matanović

1998-12-01

Full Text Available The use of coiled tubing is increasing rapidly with drilling of horizontal wells. To satisfy all requirements (larger mechanical stresses, larger fluid capacities the production of larger sizes and better material qualities was developed. Stresses due to axial forces and pressures that coiled tubing is subjected are close to its performance limits. So it is really important to know and understand the behaviour of coiled tubing to avoid its break, burst or collapse in the well.

Potential steam generator tube rupture in the presence of severe accident thermal challenge and tube flaws due to foreign object wear

International Nuclear Information System (INIS)

Liao, Y.; Guentay, S.

2009-01-01

This study develops a methodology to assess the probability for the degraded PWR steam generator to rupture first in the reactor coolant pressure boundary, under severe accident conditions with counter-current natural circulating high temperature gas in the hot leg and SG tubes. The considered SG tube flaws are caused by foreign object wear, which in recent years has emerged as a major inservice degradation mechanism for the new generation tubing materials. The first step develops the statistical distributions for the flaw frequency, size, and the flaw location with respect to the tube length and the tube's tubesheet position, based on data of hundreds of flaws reported in numerous SG inservice inspection reports. The next step performs thermal-hydraulic analysis using the MELCOR code and recent CFD findings to predict the thermal challenge to the degraded tubes and the tube-to-tube difference in thermal response at the SG entrance. The final step applies the creep rupture models in the Monte Carlo random walk to test the potential for the degraded SG to rupture before the surge line. The mean and range of the SG tube rupture probability can be applied to estimate large early release frequency in probabilistic safety assessment.

Origami tubes with reconfigurable polygonal cross-sections.

Science.gov (United States)

Filipov, E T; Paulino, G H; Tachi, T

2016-01-01

Thin sheets can be assembled into origami tubes to create a variety of deployable, reconfigurable and mechanistically unique three-dimensional structures. We introduce and explore origami tubes with polygonal, translational symmetric cross-sections that can reconfigure into numerous geometries. The tubular structures satisfy the mathematical definitions for flat and rigid foldability, meaning that they can fully unfold from a flattened state with deformations occurring only at the fold lines. The tubes do not need to be straight and can be constructed to follow a non-linear curved line when deployed. The cross-section and kinematics of the tubular structures can be reprogrammed by changing the direction of folding at some folds. We discuss the variety of tubular structures that can be conceived and we show limitations that govern the geometric design. We quantify the global stiffness of the origami tubes through eigenvalue and structural analyses and highlight the mechanical characteristics of these systems. The two-scale nature of this work indicates that, from a local viewpoint, the cross-sections of the polygonal tubes are reconfigurable while, from a global viewpoint, deployable tubes of desired shapes are achieved. This class of tubes has potential applications ranging from pipes and micro-robotics to deployable architecture in buildings.

Origami tubes with reconfigurable polygonal cross-sections

Science.gov (United States)

Filipov, E. T.; Paulino, G. H.; Tachi, T.

2016-01-01

Thin sheets can be assembled into origami tubes to create a variety of deployable, reconfigurable and mechanistically unique three-dimensional structures. We introduce and explore origami tubes with polygonal, translational symmetric cross-sections that can reconfigure into numerous geometries. The tubular structures satisfy the mathematical definitions for flat and rigid foldability, meaning that they can fully unfold from a flattened state with deformations occurring only at the fold lines. The tubes do not need to be straight and can be constructed to follow a non-linear curved line when deployed. The cross-section and kinematics of the tubular structures can be reprogrammed by changing the direction of folding at some folds. We discuss the variety of tubular structures that can be conceived and we show limitations that govern the geometric design. We quantify the global stiffness of the origami tubes through eigenvalue and structural analyses and highlight the mechanical characteristics of these systems. The two-scale nature of this work indicates that, from a local viewpoint, the cross-sections of the polygonal tubes are reconfigurable while, from a global viewpoint, deployable tubes of desired shapes are achieved. This class of tubes has potential applications ranging from pipes and micro-robotics to deployable architecture in buildings. PMID:26997894

Tube sheet design for PFBR steam generator

International Nuclear Information System (INIS)

Chellapandi, P.; Chetal, S.C.; Bhoje, S.B.

1991-01-01

Top and bottom tube sheets of PFBR Steam Generators have been analysed with 3D and axisymmetric models using CASTEM Programs. Analysis indicates that the effects of piping reactions at the inlet/outlet nozzles on the primary stresses in the tube sheets are negligible and the asymmetricity of the deformation pattern introduced in the tube sheet by the presence of inlet/outlet and manhole nozzles is insignificant. The minimum tube sheet thicknesses for evaporator and reheater are 135 mm and 75 mm respectively. Further analysis has indicated the minimum fillet radius at the junction of tube sheet and dished end should be 20 mm. Simplified methodology has been developed to arrive at the number of thermal baffles required to protect the tube sheet against fatigue damage due to thermal transient. This method has been applied to PFBR steam generators to determine the required number of thermal baffles. For protecting the bottom tube sheet of evaporator against the thermal shock due to feed water and secondary pump trip, one thermal shield is found to be sufficient. Further analysis is required to decide upon the actual number to take care of the severe thermal transient, following the event of sudden dumping of water/steam, immediately after the sodium-water reaction. (author)

Failure of fretted steam generator tubes under accident conditions

International Nuclear Information System (INIS)

Forrest, C.F.

1996-10-01

Tests were carried out with a bank of tubes in a water tunnel to determine the tolerance of flawed nuclear reactor steam generator tubes to accident conditions which would result in high cross-flow velocities. Fourteen specimen tubes were tested, each having one or two types of defect machined into the surface simulating fretting-wear type scars found in some operating steam generators. The tubes were tested at flow velocities sufficient to induce high fluid elastic-type vibrations. Seven of the tubes failed near the thinnest section of the defects during the one-hour tests, due to impacting and/or rubbing between the tube and the support. Strain gauges, displacement transducers, force gauges and an accelerometer were used on the target tube and/or the tube immediately downstream of it to measure their vibrational characteristics

21 CFR 874.1925 - Toynbee diagnostic tube.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Toynbee diagnostic tube. 874.1925 Section 874.1925...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1925 Toynbee diagnostic tube. (a) Identification. The toynbee diagnostic tube is a listening device intended to determine the degree of openness of...

Rising hopes for vacuum tube collectors

Energy Technology Data Exchange (ETDEWEB)

Godolphin, D.

1982-06-01

The performance, feasibility and use of vacuum tube solar collectors for domestic hot water (DHW) systems are discussed. An introduction to the design of vacuum tube collectors is presented and comparisons are made with flat plate collectors in terms of effectiveness in DHW applications and cost. The use of vacuum tube collectors is well established for high temperature use such as process heat and absorption cooling applications; there is considerable debate concerning their use in DHW and these arguments are presented. It is pointed out that the accepted standardized comparison test (ASHRAE 93-77) is apparently biased towards the flat plate collectors in direct comparisons of collector efficiencies. Recent developments among manufacturers with regard to vacuum tube collectors and their thinking (pro and con) are discussed in some detail. Breakage and other problems are pointed out although advocates look ahead to lower costs, higher efficiencies, and broader markets (particularly in DHW). It is concluded by some that flat plate collector technology has reached its peak and that vacuum tube collectors will be very prominent in the future. (MJJ)

Force-free thin flux tubes: Basic equations and stability

International Nuclear Information System (INIS)

Zhugzhda, Y.D.

1996-01-01

The thin flux tube approximation is considered for a straight, symmetrical, force-free, rigidly rotating flux tube. The derived set of equations describes tube, body sausage, and Alfveacute charn wave modes and is valid for any values of Β. The linear waves and instabilities of force-free flux tubes are considered. The comparison of approximate and exact solutions for an untwisted, nonrotating flux tube is performed. It is shown that the approximate and exact dispersion equations coincides, except the 20% discrepancy of sausage frequencies. An effective cross section is proposed to introduce the removal of this discrepancy. It makes the derived approximation correct for the force-free thin flux tube dynamics, except the detailed structure of radial eigenfunction. The dispersion of Alfveacute charn torsional waves in a force-free tubes appears. The valve effect of one directional propagation of waves in rotating twisted tube is revealed. The current and rotational sausage instabilities of a force-free, thin flux tube are considered. copyright 1996 American Institute of Physics

Corrosion and Rupture of Steam Generator Tubings in PWRs

Energy Technology Data Exchange (ETDEWEB)

Hwang, Seong Sik; Kim, Hong Pyo

2007-08-15

This report is intended to provide corrosion engineers in the filed of nuclear energy with information on the corrosion and rupture behavior of steam generator tubing in PWRs. Various types of corrosion in PWR steam generator tubing have been reported all around the world, and countermeasures such as the addition of corrosion inhibitors, a water chemistry control, a tube plugging and sleeving have been applied. Steam generators equipped with alloy 600 tubing, which are not so resistant to a stress corrosion cracking (SCC), have generally been replaced with new steam generators made of alloy 690 TT (Thermally treated). Pull tube examination results which were performed of KAERI are summarized. The tubes were affected by a pitting, SCC, and a denting. Nondestructive examination method for the tubes and repair techniques are also reviewed. In addition, the regulatory guidance of some countries are reviewed. As a part of a tube integrity project in Korea, some results on a tube rupture and leak behaviors for axial cracks are also mentioned.

Corrosion and Rupture of Steam Generator Tubings in PWRs

International Nuclear Information System (INIS)

Hwang, Seong Sik; Kim, Hong Pyo

2007-08-01

This report is intended to provide corrosion engineers in the filed of nuclear energy with information on the corrosion and rupture behavior of steam generator tubing in PWRs. Various types of corrosion in PWR steam generator tubing have been reported all around the world, and countermeasures such as the addition of corrosion inhibitors, a water chemistry control, a tube plugging and sleeving have been applied. Steam generators equipped with alloy 600 tubing, which are not so resistant to a stress corrosion cracking (SCC), have generally been replaced with new steam generators made of alloy 690 TT (Thermally treated). Pull tube examination results which were performed of KAERI are summarized. The tubes were affected by a pitting, SCC, and a denting. Nondestructive examination method for the tubes and repair techniques are also reviewed. In addition, the regulatory guidance of some countries are reviewed. As a part of a tube integrity project in Korea, some results on a tube rupture and leak behaviors for axial cracks are also mentioned

Teaching Shakespeare with YouTube

Science.gov (United States)

Desmet, Christy

2009-01-01

YouTube, the video sharing website that allows viewers to upload video content ranging from cute dog tricks to rare rock videos, also supports a lively community devoted to the performance of Shakespeare and Shakespearean adaptations. YouTube is also a popular site for student producers of Shakespeare performances, parodies, and other artistic…

Kartagener's Syndrome.

Science.gov (United States)

Dhar, D K; Ganguly, K C; Alam, S; Hossain, A; Sarker, U K; Das, B K; Haque, M J

2009-01-01

Kartagener's Syndrome or Immotile Cilia Syndrome, a variant of Primary Ciliary Dyskinesia (PCD), is a rare autosomal recessive genetic disorder caused by defect in the tiny hair like structure, the cilia lining the respiratory tract (upper and lower), sinuses, eustachian tubes, middle ear and fallopian tubes. Here electron microscopy shows abnormal arrangement of ciliary tubules and patients with Kartagener's syndrome has an absence of dynein arms at the base of the cilia. The inability of cilia to move results in inadequate clearance of bacteria from the air passages, resulting in an increased risk of infection and causing bronchiectasis. Another result of ciliary immobility is infertility. A 60 years old lady was diagnosed as a case of Kartagener's syndrome. She had history of chronic cough for 20 years, irregular fever for 20 years and occasional shortness of breath for 5 years. Relevant investigations revealed dextrocardia, situs inversus, bilateral maxillary sinusitis with non pneumatised frontal sinus and bronchiectasis. She was treated with low concentration oxygen inhalation, antibiotic, bronchodilator, chest physiotherapy including postural drainage, vitamins and other supportive treatment.

Experimental and numerical studies in a vortex tube

International Nuclear Information System (INIS)

Sohn, Chang Hyun; Kim, Chang Soo; Gowda, B. H. L Lakshmana; Jung, Ui Hyun

2006-01-01

The present investigation deals with the study of the internal flow phenomena of the counter-flow type vortex tube using experimental testing and numerical simulation. Visualization was carried out using the surface tracing method, injecting dye on the vortex tube wall using a needle. Vortex tube is made of acrylic to visualize the surface particle tracing and the input air pressure was varied from 0.1 MPa to 0.3 MPa. The experimentally visualized results on the tube show that there is an apparent sudden changing of the trajectory on the vortex tube wall which was observed in every experimental test case. This may indicate the stagnation position of the vortex flow. The visualized stagnation position moves towards the vortex generator with increase in cold flow ratio and input pressure. Three-dimensional computational study is also conducted to obtain more detailed flow information in the vortex tube. Calculated total pressure, static pressure and total temperature distributions in the vortex tube were in good agreement with the experimental data. The computational particle trace on the vortex tube wall is very similar to that observed in experiments

Synthesis and characterization of magnetite/hydroxyapatite tubes ...

Indian Academy of Sciences (India)

The first step is the formation of magnetite (Fe 3 O 4 ) tubes on natural template followed by hydroxyapatite (HAp) bioceramic coated on the Fe 3 O 4 tubes. HAp improves the biocompatibility and stability of the prepared tubes. Sintering at 900 ∘ C improves the crystalline stability of nanotubes and removes the natural ...

Building lab-scale x-ray tube based irradiators

International Nuclear Information System (INIS)

Haff, Ron; Jackson, Eric; Gomez, Joseph; Light, Doug; Follett, Peter; Simmons, Greg; Higbee, Brad

2016-01-01

Here we report the use of x-ray tube based irradiators as alternatives to gamma sources for laboratory scale irradiation. Irradiators were designed with sample placement in closest possible proximity to the source, allowing high dose rates for small samples. Designs using 1000 W x-ray tubes in single tube, double tube, and four tube configurations are described, as well as various cabinet construction techniques. Relatively high dose rates were achieved for small samples, demonstrating feasibility for laboratory based irradiators for research purposes. Dose rates of 9.76, 5.45, and 1.7 Gy/min/tube were measured at the center of a 12.7 cm container of instant rice at 100 keV, 70 keV, and 40 keV, respectively. Dose uniformity varies dramatically as the distance from source to container. For 2.54 cm diameter sample containers containing adult Navel Orangeworm, dose rates of 50–60 Gy/min were measured in the four tube system. - Highlights: • X-ray is demonstrated as an alternative to gamma for lab-based irradiation. • Cabinets using one, two, and four 1000 W tubes are reported. • Dose rate of 9.8 Gy/min/tube at the center of a 12.7 cm container of instant rice. • Dose uniformity varies dramatically as the distance from source to container.

The YouTube reader

OpenAIRE

2009-01-01

YouTube has come to epitomize the possibilities of digital culture. With more than seventy million unique users a month and approximately eighty million videos online, this brand-name video distribution platform holds the richest repository of popular culture on the Internet. As the fastest growing site in the history of the Web, YouTube promises endless new opportunities for amateur video, political campaigning, entertainment formats, and viral marketing—a clip culture that has seemed to out...

High-temperature transient creep properties of CANDU pressure tubes

International Nuclear Information System (INIS)

Fong, R.W.L.; Chow, C.K.

2002-06-01

During a hypothetical large break loss-of-coolant accident (LOCA), the coolant flow would be reduced in some fuel channels and would stagnate and cause the fuel temperature to rise and overheat the pressure tube. The overheated pressure tube could balloon (creep radially) into contact with its moderator-cooled calandria tube. Upon contact, the stored thermal energy in the pressure tube is transferred to the calandria tube and into the moderator, which acts as a heat sink. For safety analyses, the modelling of fuel channel deformation behaviour during a large LOCA requires a sound knowledge of the high-temperature creep properties of Zr-2.5Nb pressure tubes. To this extent, a ballooning model to predict pressure-tube deformation was developed by Shewfelt et al., based on creep equations derived using uniaxial tensile specimens. It has been recognized, however, that there is an inherent variability in the high-temperature creep properties of CANDU pressure tubes. The variability, can be due to different tube-manufacturing practices, variations in chemical compositions, and changes in microstructure induced by irradiation during service in the reactor. It is important to quantify the variability of high-temperature creep properties so that accurate predictions on pressure-tube creep behaviour can be made. This paper summarizes recent data obtained from high-temperature uniaxial creep tests performed on specimens taken from both unirradiated (offcut) and irradiated pressure tubes, suggesting that the variability is attributed mainly to the initial differences in microstructure (grain size, shape and preferred orientation) and also from tube-to-tube variations in chemical composition, rather than due to irradiation exposure. These data will provide safety analysts with the means to quantify the uncertainties in the prediction of pressure-tube contact temperatures during a postulated large break LOCA. (author)

Nervous system examination on YouTube

OpenAIRE

Azer Samy A; AlEshaiwi Sarah M; AlGrain Hala A; AlKhelaif Rana A

2012-01-01

Abstract Background Web 2.0 sites such as YouTube have become a useful resource for knowledge and are used by medical students as a learning resource. This study aimed at assessing videos covering the nervous system examination on YouTube. Methods A research of YouTube was conducted from 2 November to 2 December 2011 using the following key words “nervous system examination”, “nervous system clinical examination”, “cranial nerves examination”, “CNS examination”, “examination of cerebellum”, “...

Visual beam tube inspection at the TRIGA reactor Vienna

International Nuclear Information System (INIS)

Boeck, H.; Musilek, A.; Villa, M.

2006-01-01

Of the four TRIGA beam tubes two have been visually inspected in 1985. Prior to the inspection the reactor was shut down for 3 weeks. The fuel elements around the beam tubes were removed. Stainless steel dummy elements were inserted in the fuel positions to shield the core radiation. The active part of the Fast Rabbit Tube was removed into the beam tube loading device and transferred to an interim storage: Front dose rate was ∼ 50 mSv/h. Generally the beam tube was very clean, after the last inspection about 30 years ago. A1 cm cut was observed at the beam tube front end. A rigid endoscope was used to check the beam tube's inner surface using a 90 degree deflection objective and photo- and video equipment. The direct dose rate in front of the beam tube was about 30 mSv/h. The beam tube was vacuum cleaned. A corroded shielding tank containing boric acid has leaked. A wooden collimator partially disintegrating due to extreme temperature was removed from beam tube D. Documentation of the inspection for visible defects is produced for later comparison

Flowmeter with silicon flow tube

NARCIS (Netherlands)

Lammerink, Theodorus S.J.; Dijkstra, Marcel; Haneveld, J.; Lötters, Joost Conrad

2009-01-01

A flowmeter comprising a system chip with a silicon substrate provided on a carrier, in an opening whereof at least one silicon flow tube is provided for transporting a medium whose flow rate is to be measured, said tube having two ends that issue via a wall of the opening into channels coated with

A Novel Device for Accurate Chest Tube Insertion

DEFF Research Database (Denmark)

Katballe, Niels; Moeller, Lars B; Olesen, Winnie H

2016-01-01

BACKGROUND: Optimal positioning of a large-bore chest tube is in the part of the pleural cavity that needs drainage. It is recommended that the chest tube be positioned apically in pneumothorax and basally for fluids. However, targeted chest tube positioning to a specific part of the pleural cavity...... can be a challenge. METHODS: A new medical device, the KatGuide, was developed for accurate guiding of a chest tube (28F) to an intended part of the pleural cavity. The primary end point of this randomized, controlled trial was optimal position of the chest tube. The optimal position in pneumothorax...

Disinfection of Biofilms in Tubes with Ultraviolet Light

DEFF Research Database (Denmark)

Bak, Jimmy; Begovic, Tanja

2009-01-01

Bacterial biofilms on long-term catheters are a major source of infection. We demonstrate here the potential of UVC light emitting diodes (LED) for disinfection purposes in catheter like tubes contaminated with biofilm. We show that UVC Light propagation is possible through teflon tubes using...... to a flow system and biofilms were produced during a three day period. Tubes in lengths of 10 cm (FEP teflon) were contaminated. Tubes for control and for UVC treatment were contaminated in parallel. The control and UVC treated tubes were both filled with a 20 % NaCl solution during the UVC treatment time...

Hydrogen isotope exchange in a metal hydride tube

Energy Technology Data Exchange (ETDEWEB)

Robinson, David B. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2014-09-01

This report describes a model of the displacement of one hydrogen isotope within a metal hydride tube by a different isotope in the gas phase that is blown through the tube. The model incorporates only the most basic parameters to make a clear connection to the theory of open-tube gas chromatography, and to provide a simple description of how the behavior of the system scales with controllable parameters such as gas velocity and tube radius. A single tube can be seen as a building block for more complex architectures that provide higher molar flow rates or other advanced design goals.

YouTube, "Drug Videos" and Drugs Education

Science.gov (United States)