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  • 1
    Electronic Resource
    Electronic Resource
    Preparations for deuterium–tritium experiments on the Tokamak Fusion Test Reactor* (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 1 (1994), S. 1560-1567 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The final hardware modifications for tritium operation have been completed for the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. These activities include preparation of the tritium gas handling system, installation of additional neutron shielding, conversion of the toroidal field coil cooling system from water to a FluorinertTM system, modification of the vacuum system to handle tritium, preparation, and testing of the neutral beam system for tritium operation and a final deuterium–deuterium (D–D) run to simulate expected deuterium–tritium (D–T) operation. Testing of the tritium system with low concentration tritium has successfully begun. Simulation of trace and high power D–T experiments using D–D have been performed. The physics objectives of D–T operation are production of ≈10 MW of fusion power, evaluation of confinement, and heating in deuterium–tritium plasmas, evaluation of α-particle heating of electrons, and collective effects driven by alpha particles and testing of diagnostics for confined α particles. Experimental results and theoretical modeling in support of the D–T experiments are reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.870707
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  • 2
    Electronic Resource
    Electronic Resource
    Review of deuterium–tritium results from the Tokamak Fusion Test Reactor (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 2176-2188 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: After many years of fusion research, the conditions needed for a D–T fusion reactor have been approached on the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. For the first time the unique phenomena present in a D–T plasma are now being studied in a laboratory plasma.The first magnetic fusion experiments to study plasmas using nearly equal concentrations of deuterium and tritium have been carried out on TFTR. At present the maximum fusion power of 10.7 MW, using 39.5 MW of neutral-beam heating, in a supershot discharge and 6.7 MW in a high-βp discharge following a current rampdown. The fusion power density in a core of the plasma is ≈2.8 MW m−3, exceeding that expected in the International Thermonuclear Experimental Reactor (ITER) [Plasma Physics and Controlled Nuclear Fusion Research (International Atomic Energy Agency, Vienna, 1991), Vol. 3, p. 239] at 1500 MW total fusion power. The energy confinement time, τE, is observed to increase in D–T, relative to D plasmas, by 20% and the ni(0) Ti(0) τE product by 55%. The improvement in thermal confinement is caused primarily by a decrease in ion heat conductivity in both supershot and limiter-H-mode discharges. Extensive lithium pellet injection increased the confinement time to 0.27 s and enabled higher current operation in both supershot and high-βp discharges. Ion cyclotron range of frequencies (ICRF) heating of a D–T plasma, using the second harmonic of tritium, has been demonstrated. First measurements of the confined alpha particles have been performed and found to be in good agreement with TRANSP [Nucl. Fusion 34, 1247 (1994)] simulations. Initial measurements of the alpha ash profile have been compared with simulations using particle transport coefficients from He gas puffing experiments. The loss of alpha particles to a detector at the bottom of the vessel is well described by the first-orbit loss mechanism. No loss due to alpha-particle-driven instabilities has yet been observed. D–T experiments on TFTR will continue to explore the assumptions of the ITER design and to examine some of the physics issues associated with an advanced tokamak reactor. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871303
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of TFTR far-field neutron detector efficiencies by local neutron flux spectrum measurement : Proceedings of the eleventh topical conference on high temperature plasma diagnostics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 540-543 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Neutron detectors have often been located on the tokamak fusion test reactor (TFTR) test cell floor 3 m or more from the vacuum vessel for ease of detector access, to reduce radiation damage, minimize count saturation problems, and to avoid high magnetic fields. These detectors include Si surface-barrier diodes, fission chambers, natural diamond detectors, and T2 production in a moderated 3He cell. To evaluate the performance of these detectors during deuterium–tritium (D–T) operation, we determined the neutron flux spectrum incident on the principal detector enclosure using nuclide sample sets containing Al, Ti, Fe, Co, Cu, Zn, Ni, Zr, Nb, In, and Au activation foils. Foils were installed and then removed after ample exposure to TFTR D–T neutrons. High efficiency, high purity Ge detectors were used for gamma spectroscopy of the irradiated foils. The incident neutron fluence and spectral distribution were unfolded from the measured results, and used to derive absolute detector efficiencies. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147647
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  • 4
    Electronic Resource
    Electronic Resource
    Review of diagnostic methods for TFTR D–T radiation shielding and neutronics studies : Proceedings of the eleventh topical conference on high temperature plasma diagnostics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 557-560 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The methods and instrument systems used for TFTR D–T radiation shielding and neutronics studies involving signal strengths ranging over 10 orders of magnitude are reviewed. Neutron and gamma dose-equivalent, fluence, spectral, and materials activation measurements have been performed at various locations from the TFTR vessel to the nearest property lines. The detection systems include 3He, BF3, and 235U proportional counters in moderated spheres, Bonner sphere arrays, advanced thermoluminescent detectors, argon ionization chambers, intrinsic Ge gamma detectors, and activation foil spectrometry methods. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147652
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  • 5
    Electronic Resource
    Electronic Resource
    Tritium production in He-3 gas cells immersed in the Tokamak Fusion Test Reactor neutron field : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1115-1118 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Tritium generated in an external cell by the reaction 3He(n,p)T can be used as a gauge of long-term fusion neutron production, because of the 12-year half-life of T and the relative ease of measuring the T content either by sampling or from the saturation current of the cell when operated as an ionization chamber. Two high-pressure 3He gas cells enclosed in polyethylene neutron moderators were exposed to Tokamak Fusion Test Reactor (TFTR) neutrons during high-power D–T operation. The tritium produced in the cells was assayed by the Princeton Differential Atmospheric Tritium Sampler. The measured tritium generated per 1019 fusion neutrons was 510 pCi/cc at 2.3 m from the TFTR vessel and 1.3 m below the midplane, and 2020 pCi/cc at 1.0 m from the TFTR vessel in the midplane. Combining these results with previous measurements at a third location, we found 0.11 to 0.23 triton produced per neutron incident on the projected cell cross section, with an asymptotic local tritium breeding ratio of 0.32. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149427
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  • 6
    Electronic Resource
    Electronic Resource
    Pediatric laparoscopic splenectomy: are there real advantages in comparison with the traditional open approach? (1997)
    Springer
    Pediatric surgery international 12 (1997), S. 509-510 
    Details
    ISSN: 1437-9813
    Keywords: Laparoscopy ; Splenectomy ; Children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The hospital records of patients who underwent splenectomy during the last 2 years were reviewed to compare the advantages of the laparoscopic approach with traditional open splenectomy (OS). Between March 1994 and March 1996, 16 children underwent splenectomy, in 8 using an open approach and 8 by a laparoscopic procedure. Of the patients who underwent laparoscopic splenectomy (LS), 2 had a concomitant cholecystectomy. Ages ranged between 4 and 11 years (mean 6.4 years); there were 9 girls and 7 boys. The indications for splenectomy were: hereditary spherocytosis (7 cases); idiopathic thrombocytopenic purpura (4); sickle-cell disease (3); and β-thalassemia (2). The average operating time for OS was 100 min (range, 50–155), for LS 170 min (range 125–240). The hospital stay for patients who had OS ranged from 3 to 9 days (mean 4.7), for those who had LS from 2 to 5 days (mean 3). One OS patient developed a wound infection. In 3 of the LS patients, the spleen was removed via a 7-cm Pfannenstiel minilaparotomy in the suprapubic region; in 5 cases the spleen was captured into an extraction bag, crushed, and removed through the umbilical orifice. The authors believe that LS must be performed only when it is possible to use the extraction bag to remove the spleen from the umbilical orifice (spleens weighing less than 700 g) and when a concomitant procedure such as cholecystectomy is indicated; in other cases OS is preferable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01258713
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  • 7
    Electronic Resource
    Electronic Resource
    Pediatric laparoscopic splenectomy: are there real advantages in comparison with the traditional open approach? (1997)
    Springer
    Pediatric surgery international 12 (1997), S. 509-510 
    Details
    ISSN: 1437-9813
    Keywords: Key words Laparoscopy ; Splenectomy ; Children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The hospital records of patients who underwent splenectomy during the last 2 years were reviewed to compare the advantages of the laparoscopic approach with traditional open splenectomy (OS). Between March 1994 and March 1996, 16 children underwent splenectomy, in 8 using an open approach and 8 by a laparoscopic procedure. Of the patients who underwent laparoscopic splenectomy (LS), 2 had a concomitant cholecystectomy. Ages ranged between 4 and 11 years (mean 6.4 years); there were 9 girls and 7 boys. The indications for splenectomy were: hereditary spherocytosis (7 cases); idiopathic thrombocytopenic purpura (4); sickle-cell disease (3); and β-thalassemia (2). The average operating time for OS was 100 min (range, 50–155), for LS 170 min (range 125–240). The hospital stay for patients who had OS ranged from 3 to 9 days (mean 4.7), for those who had LS from 2 to 5 days (mean 3). One OS patient developed a wound infection. In 3 of the LS patients, the spleen was removed via a 7-cm Pfannenstiel minilaparotomy in the suprapubic region; in 5 cases the spleen was captured into an extraction bag, crushed, and removed through the umbilical orifice. The authors believe that LS must be performed only when it is possible to use the extraction bag to remove the spleen from the umbilical orifice (spleens weighing less than 700 g) and when a concomitant procedure such as cholecystectomy is indicated; in other cases OS is preferable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01258713
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  • 8
    Electronic Resource
    Electronic Resource
    Complications of pediatric laparoscopic surgery (1997)
    Springer
    Surgical endoscopy and other interventional techniques 11 (1997), S. 655 -657 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Complications — Open approach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Surgical complications of laparoscopy most often occur during Veress needle or primary trocar placement. Veress needle punctures are insignificant and require no further treatment, whereas trocar-induced vascular injuries can be catastrophic. The frequency of vascular and viscus injuries is difficult to calculate because several complications are not reported in the literature. Methods: During a 10-year-period (1984–1995), at the Division of Pediatric Surgery at ``Federico II'' University of Naples, 430 laparoscopic procedures were performed in 395 children with a mean age of 5 years. The incidence of complications related to laparoscopy was 1.8% with eight complications, one of which was rather severe. The complications included one abdominal wall hematoma, two perforations of abdominal viscus (stomach, ovary), one umbilical scar complication, one postoperative hydrocele, one subcutaneous emphysema, and one pneumothorax during a Nissen procedure. The only severe complication occurred in a young girl with neurologic problems and a kyphoscoliosis operated on via laparoscopy for a gastroesophageal reflux. She suffered injuries of both right common iliac vessels and several intestinal perforations due to blind introduction of the first umbilical trocar. Results: In this case rapid conversion, complex vascular reconstruction, and multiple intestinal sutures were performed. The Nissen fundoplication with pyloroplasty was performed traditionally and the patient left the hospital free of symptoms after 20 days. The other seven complications were resolved without any problem intra- or postoperatively. Conclusions: The authors believe that the open approach with a blunt trocar is most important in helping to avoid complications in pediatric laparoscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900415
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  • 9
    Electronic Resource
    Electronic Resource
    Splenectomy in childhood (1998)
    Springer
    Surgical endoscopy and other interventional techniques 12 (1998), S. 1445-1448 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Splenectomy — Children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: We set out to analyze the results of the first 19 laparoscopic splenectomies performed by our team in order to show the advantages and limitations of the laparoscopic approach to this kind of procedure in children. Methods: Between March 1994 and June 1997, 19 children underwent laparoscopic splenectomy; two of them also had a concomitant cholecystectomy. Their ages ranged between 4 and 14 years (median, 7.2 years). There were 14 girls and 5 boys. All the patients underwent elective laparoscopic splenectomy: seven children had hereditary spherocytosis, six were affected by a β thalassemia, five had an idiopathic thrombocytopenia purpura, and one presented with sickle cell disease. Results: Mean operating time was 145 min (range, 110–240 min). Hospital stay ranged from 2 to 5 days (median, 3 days). In three patients, the spleen was removed with a 7-cm mini-laparotomy, according to the technique of Pfannenstiell, in the suprapubic region. In the other 16 cases, the spleen was captured into a extraction bag, finger-fragmented, and removed from the umbilical orifice. Conclusions: Laparoscopic splenectomy can be performed only when the spleen can be removed through the umbilical orifice with an extraction bag. For this reason, preoperative ultrasonography is necessary to measure the exact spleen volume. When the spleen is very large, an open splenectomy is preferable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900879
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