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Sample records for pulpal chamber temperature

  1. Effect of repeated refrigerant spray applications using various carriers on pulpal temperature change.

    PubMed

    Garza, Christopher A; Vandewalle, Kraig S; Sabey, Kent A; Hamilton, Garrett J; Chong, Chol H

    2010-01-01

    This study sought to determine how repeated applications of a refrigerant spray on various cotton carriers affected the change in pulpal temperature. A thermocouple was placed at the roof of the pulp chamber of a human maxillary canine and connected to a thermometer logging at one-second intervals while the root was immersed in a water bath at 37 degrees C. Four different carrier types were used: large cotton pellets, small cotton pellets, cotton-tip applicators, and cotton rolls. Each carrier was sprayed with 1,1,1,2-tetrafluoroethane and placed on the crown for five seconds. Pulpal temperature change was recorded after each five second application of the same carrier to the tooth until a total of six consecutive sprays and applications of the carrier were applied. Each carrier group consisted of 10 performances of the six sets of readings (n = 10). The difference between baseline and the low temperature reading was calculated to determine the temperature change (in degrees C) in the pulp chamber per application. When the refrigerant spray was used, the large cotton pellet carrier generally produced the largest decrease in pulpal temperature at each repeated application compared to the other types of carriers. However, the same large cotton pellet should not be sprayed with the refrigerant more than two times before it is replaced. PMID:20478789

  2. Effects of different dentin thicknesses and air cooling on pulpal temperature rise during laser welding.

    PubMed

    Secilmis, Asli; Bulbul, Mehmet; Sari, Tugrul; Usumez, Aslihan

    2013-01-01

    The neodymium/yttrium-aluminum-garnet (Nd/YAG) laser has been suggested to repair broken prostheses in the mouth. This study investigated the effects of different dentin thicknesses and air cooling on pulpal temperature rise during laser welding. Three intact human maxillary molars were prepared for full-veneer crown. For each tooth, dentin thicknesses in mesiobuccal cusp was 2, 3, or 4 mm. Twenty dies were duplicated from each of the prepared teeth. For metal copings with 0.5-mm thickness, wax patterns were prepared with dip wax technique directly onto each of dies. All patterns were sprued and invested. The castings were made using a nickel-chromium alloy (Nicromed Premium, Neodontics). A hole with 0.5-mm diameter was prepared on the mesiobuccal cusp of each crown. The Nd/YAG laser (9.85 W; 1 Hz repetition rate; fluence, 1.230 J/cm(2); Fidelis Plus 3, Fotona) was used for welding with or without air cooling (n = 10). The temperature rise was measured in pulpal chamber with a J-type thermocouple wire that was connected to a data logger. Differences between start and highest temperature reading were taken, and temperature rise values were compared using two-way analysis of variance and Tukey's honestly significant difference tests (α = .05). Pulpal temperature rise varied significantly depending on the dentin thickness and air cooling (p < 0.05). The non-air cooling group induced significantly the highest temperature increases. There were no significant differences between 2- and 3-mm dentin thicknesses groups (p > 0.05); however, pulpal temperature rise was the lowest for 4-mm dentin thickness group (p < 0.05). The highest values of thermal increase were found in the pulp chamber (6.8°C) when no air cooling was used in 2-mm dentin thickness group. Laser welding on base metal castings with Nd/YAG laser can be applied with air cooling to avoid temperature rises known to adversely affect pulpal health when dentin thickness is 2 or 3 mm. PMID:22562450

  3. Effect of simulated pulpal fluid circulation on intrapulpal temperature following irradiation with an Nd:YVO4 laser.

    PubMed

    Braun, Andreas; Kecsmar, Susann; Krause, Felix; Berthold, Michael; Frentzen, Matthias; Frankenberger, Roland; Schelle, Florian

    2015-05-01

    It is suggested that pulpal fluid circulation has an impact on pulp temperature increase during heat-generating dental treatment procedures. Thus, the aim of the study was to assess the effect of a simulated pulpal fluid circulation on temperature changes inside the pulp chamber following laser irradiation of the tooth surface. Twenty freshly extracted human multirooted teeth were included and cross-sectioned along the long axis exposing two root canals each. The pulp chamber and root canals were cleaned from remaining soft tissues to achieve access for a temperature sensor and two cannulas to allow fluid circulation. Cross sections were glued together, and the roots were encased with silicone impression material to ensure the position of the connected devices. Each tooth was irradiated by employing a neodymium-doped yttrium orthovanadate (Nd:YVO4) laser at 1,064 nm with a pulse duration of 9 ps and a repetition rate of 500 kHz. A commercially available scanning system (SCANcube 7, SCANLAB) deflected the beam by providing rectangular irradiated areas of 0.5 mm edge length. Measurements were performed with four different settings for fluid circulation: without any water and with water (23 °C) at a flow rate of 6, 3, and 0 ml/min. The primary outcome measure was the maximum temperature difference (ΔT) after laser irradiation. Highest temperature changes (median 3.6 K, range 0.5-7.1 K) could be observed without any fluid inside the pulp chamber. Water without circulation decreased ΔT values statistically significantly (median 1.4 K, range 0.2-4.9 K) (p < 0.05). Lowest temperature changes could be observed with a water flow rate of 6 ml/min (median 0.8 K, range 0.2-3.7 K) (p < 0.05). Pulpal fluid circulation has a cooling effect on temperature increase caused by laser irradiation of dental hard tissues. Studies on heat generation during dental treatment procedures should include this aspect to assess a potential thermal injury of pulp tissue. PMID:24578013

  4. Surface and pulpal temperature comparison of tooth whitening using lasers and curing lights

    NASA Astrophysics Data System (ADS)

    White, Joel M.; Pelino, Jose; Rodrigues, Rively; Zwhalen, Brian J.; Nguyen, Max H.; Wu, Emily

    2000-03-01

    Chemical action of bleaching agents applied to tooth surface is accelerated by increase in temperature. This in vitro study measured the temperature rises on the surface and in the pulp of teeth during whitening using a diode laser, a plasma arc curing (PAC) light and conventional curing lights. Extracted, non-carious single-rooted teeth were exposed to PAC light and laser at times ranging from 10 to 60 seconds and energy ranges of 2 W, 4 W, and 6 W, and to low-intensity curing lights from 1 to 4 minutes. Maximum temperature rises were analyzed for both pulpal and surface temperature. Diode laser exposures at 2 W for all times and at 4 watts for 10 seconds and PAC light exposures at 10 seconds all produced acceptably safe pulpal rises equivalent to conventional light-curing exposures. Exposures at these settings also attained surface temperature rises that were significantly higher than those using conventional light-curing. The diode laser demonstrated bleaching results equivalent to the PAC light, and both were achieved in significantly less times than conventional light- curing.

  5. Pulpal-temperature rise and polymerization efficiency of LED curing lights.

    PubMed

    Leprince, Julian; Devaux, Jacques; Mullier, Thérèse; Vreven, José; Leloup, Gaetane

    2010-01-01

    This paper assesses the effects of light characteristics and irradiation time on the Vickers microhardness (VH) of a dual-photoinitiator commercial composite and on temperature increase in the pulp chamber (deltaT). Four recent light-emitting diodes (LEDs)--bluephaseG2 (BG2), bluephase16i (B16i), G-Light (G) and Freelight2 (F2)--and one control halogen light (XL3000-X) were tested on two shades of Tetric EvoCeram (A2 and Bleach XL), whose respective commercial formulations differed based on their concentration of camphorquinone and lucirin TPO. Three different irradiation times were applied--10, 20 and 40 seconds-and VH was measured on the upper and lower surfaces of 2-mm thick samples. The deltaT was measured by using a K-type thermocouple inserted into the pulp chamber of a molar that had been prepared to obtain a 2-mm thickness of dentin. The measurements were made either during polymerization of a 2 mm composite (Shade A2 or Bleach) or with an empty mold. The data were analyzed with the two-way ANOVA (p < 0.05) test. For shade A2, all but one irradiation condition (F2-10 seconds, lower surface) generated VH values that were statistically equal to or better than the standard chosen for this study (X-40 seconds). For Bleach shade, the VH values obtained with G and BG2-20 and 40 seconds were statistically comparable to X-40 seconds for both the upper and lower surfaces. This was not the case with either G and BG2-10 seconds or for all the procedures with other LCUs for which a VH of at least one of the surfaces was significantly lower than the reference. The results also highlight differences between the two material shades, whether the upper or lower surface is considered. Regarding temperature measurements for shade A2, B16i-20-40 seconds, BG2-40 seconds and G-40 seconds induced significantly higher deltaTs (3.98, 5.98, 5.21 and 4.95, respectively) than X-40 seconds (3.09). For Bleach shade, B16i-20 and 40 seconds, F2-20 and 40 seconds, BG2-40 seconds and G-40

  6. Influence of Nd:YAG laser on intrapulpal temperature and bond strength of human dentin under simulated pulpal pressure.

    PubMed

    Silva, T M; Gonçalves, L L; Fonseca, B M; Esteves, S R M S; Barcellos, D C; Damião, A J; Gonçalves, S E P

    2016-01-01

    The aim of this study was to evaluate the effects of simulated pulpal pressure (SPP) on the variation of intrapulpal temperature (ΔT) and microtensile bond strength (μTBS) to dentin submitted to an adhesive technique using laser irradiation. One hundred sound human molars were randomly divided into two groups (n = 50), according to the presence or absence of SPP (15 cm H2O). Each group was divided into five subgroups (n = 10) according to Nd:YAG laser energy (60, 80, 100, 120, 140 mJ/pulse). The samples were sequentially treated with the following: 37 % phosphoric acid, adhesive (Scotchbond Universal), irradiation with Nd:YAG laser (60 s), and light curing (10 s). ΔT was evaluated during laser irradiation using a type K thermocouple. Next, a composite resin block was build up onto the irradiated area. After 48 h, samples were submitted to microtensile test (10 kgf load cell, 0.5 mm/min). Data were analyzed by two-way ANOVA and Tukey tests (p = 0.05). ANOVA revealed significant differences for ΔT and TBS in the presence of SPP. For ΔT, the highest mean (14.3 ± 3.23 °C)(A) was observed in 140 mJ and without SPP. For μTBS, the highest mean (33.4 ± 4.15 MPa)(A) was observed in 140 mJ and without SPP. SPP significantly reduced both ΔT and μTBS during adhesive procedures, lower laser energy parameters resulted in smaller ΔT, and the laser parameters did not influence the μTBS values. PMID:26510575

  7. Diagnostic and clinical factors associated with pulpal and periapical pain.

    PubMed

    Estrela, Carlos; Guedes, Orlando Aguirre; Silva, Júlio Almeida; Leles, Cláudio Rodrigues; Estrela, Cyntia Rodrigues de Araújo; Pécora, Jesus Djalma

    2011-01-01

    A retrospective survey was designed to identify diagnostic subgroups and clinical factors associated with odontogenic pain and discomfort in dental urgency patients. A consecutive sample of 1,765 patients seeking treatment for dental pain at the Urgency Service of the Dental School of the Federal University of Goiás, Brazil, was selected. Inclusion criteria were pulpal or periapical pain that occurred before dental treatment (minimum 6 months after the last dental appointment), and the exclusion criteria were teeth with odontogenic developmental anomalies and missing information or incomplete records. Clinical and radiographic examinations were performed to assess clinical presentation of pain complaints including origin, duration, frequency and location of pain, palpation, percussion and vitality tests, radiographic features, endodontic diagnosis and characteristics of teeth. Chi-square test and multiple logistic regression were used to analyze association between pulpal and periapical pain and independent variables. The most frequent endodontic diagnosis of pulpal pain were symptomatic pulpitis (28.3%) and hyperreactive pulpalgia (14.4%), and the most frequent periapical pain was symptomatic apical periodontitis of infectious origin (26.4%). Regression analysis revealed that closed pulp chamber and caries were highly associated with pulpal pain and, conversely, open pulp chamber was associated with periapical pain (p<0.001). Endodontic diagnosis and local factors associated with pulpal and periapical pain suggest that the important clinical factor of pulpal pain was closed pulp chamber and caries, and of periapical pain was open pulp chamber. PMID:21861030

  8. Laser all-ceramic crown removal and pulpal temperature--a laboratory proof-of-principle study.

    PubMed

    Rechmann, P; Buu, N C H; Rechmann, B M T; Finzen, F C

    2015-11-01

    The objective of this proof-of-principle laboratory pilot study was to evaluate the temperature increase in the pulp chamber in a worst case scenario during Er:YAG laser debonding of all-ceramic crowns. Twenty extracted molars were prepared to receive all-ceramic IPS E.max CAD full contour crowns. The crowns were bonded to the teeth with Ivoclar Multilink Automix. Times for laser debonding and temperature rise in the pulp chamber using micro-thermocouples were measured. The Er:YAG was used with 560 mJ/pulse. The irradiation was applied at a distance of 5 mm from the crown surface. Additional air-water spray for cooling was utilized. Each all-ceramic crown was successfully laser debonded with an average debonding time of 135 ± 35 s. No crown fractured, and no damage to the underlying dentin was detected. The bonding cement deteriorated, but no carbonization at the dentin/cement interface occurred. The temperature rise in the pulp chamber averaged 5.4° ± 2.2 °C. During 8 out of the 20 crown removals, the temperature rise exceeded 5.5 °C, lasting 5 to 43 s (average 18.8 ± 11.6 s). A temperature rise of 11.5 °C occurred only once, while seven times the temperature rise was limited to 6.8 ± 0.5 °C. Temperature rises above 5.5 °C occurred only when the laser was applied from one side and additional cooling from the side opposite the irradiation. Er:YAG laser energy can successfully be used to efficiently debond all-ceramic crowns from natural teeth. Temperature rises exceeding 5.5 °C only occur when an additional air/water cooling from a dental syringe is inaccurately directed. To avoid possible thermal damage and to allow further heat diffusion, clinically temperature-reduced water might be applied. PMID:25782432

  9. High temperature thrust chamber for spacecraft

    NASA Technical Reports Server (NTRS)

    Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

    1998-01-01

    A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

  10. Temperature Changes of Pulp Chamber during In Vitro Laser Welding of Orthodontic Attachments

    PubMed Central

    İşman, Eren; Okşayan, Rıdvan; Sökücü, Oral; Üşümez, Serdar

    2014-01-01

    The use of lasers has been suggested for orthodontists to fabricate or repair orthodontic appliances by welding metals directly in the mouth. This work aimed to evaluate the temperature changes in the pulp chamber during welding of an orthodontic wire to an orthodontic molar band using Nd : YAG laser in vitro. A freshly extracted human third molar with eliminated pulpal tissues was used. J-type thermocouple wire was positioned in the pulp chamber. A conductor gel was used in the transferring of outside temperature changes to the thermocouple wire. An orthodontic band was applied to the molar tooth and bonded using light cured orthodontic cement. Twenty five mm length of 0.6 mm diameter orthodontic stainless steel wires was welded to the orthodontic band using Nd : YAG laser operated at 9.4 watt. Temperature variation was determined as the change from baseline temperature to the highest temperature was recorded during welding. The recorded temperature changes were between 1.8 and 6.8°C (mean: 3.3 ± 1.1°C). The reported critical 5.5°C level was exceeded in only one sample. The results of this study suggest that intraoral use of lasers holds great potential for the future of orthodontics and does not present a thermal risk. Further studies with larger samples and structural analysis are required. PMID:24550714

  11. Temperature changes of pulp chamber during in vitro laser welding of orthodontic attachments.

    PubMed

    Işman, Eren; Okşayan, Rıdvan; Sökücü, Oral; Üşümez, Serdar

    2014-01-01

    The use of lasers has been suggested for orthodontists to fabricate or repair orthodontic appliances by welding metals directly in the mouth. This work aimed to evaluate the temperature changes in the pulp chamber during welding of an orthodontic wire to an orthodontic molar band using Nd : YAG laser in vitro. A freshly extracted human third molar with eliminated pulpal tissues was used. J-type thermocouple wire was positioned in the pulp chamber. A conductor gel was used in the transferring of outside temperature changes to the thermocouple wire. An orthodontic band was applied to the molar tooth and bonded using light cured orthodontic cement. Twenty five mm length of 0.6 mm diameter orthodontic stainless steel wires was welded to the orthodontic band using Nd : YAG laser operated at 9.4 watt. Temperature variation was determined as the change from baseline temperature to the highest temperature was recorded during welding. The recorded temperature changes were between 1.8 and 6.8°C (mean: 3.3±1.1°C). The reported critical 5.5°C level was exceeded in only one sample. The results of this study suggest that intraoral use of lasers holds great potential for the future of orthodontics and does not present a thermal risk. Further studies with larger samples and structural analysis are required. PMID:24550714

  12. Dental caries and pulpal disease.

    PubMed

    Zero, Domenick T; Zandona, Andrea Ferreira; Vail, Mychel Macapagal; Spolnik, Kenneth J

    2011-01-01

    This article reviews the diagnostic process, from the first clinically evident stages of the caries process to development of pulpal pathosis. The caries diagnostic process includes 4 interconnected components-staging caries lesion severity, assessing caries lesion activity, and risk assessments at the patient and tooth surface level - which modify treatment decisions for the patient. Pulpal pathosis is diagnosed as reversible pulpitis, irreversible pulpitis (asymptomatic), irreversible pulpitis (symptomatic), and pulp necrosis. Periapical disease is diagnosed as symptomatic apical periodontitis, asymptomatic apical periodontitis, acute apical abscess, and chronic apical abscess. Ultimately, the goal of any diagnosis should be to achieve better treatment decisions and health outcomes for the patient. PMID:21094717

  13. Investigation on temperature separation and flow behaviour in vortex chamber

    NASA Astrophysics Data System (ADS)

    Matsuno, Yuhi; Fukushima, Yusuke; Matsuo, Shigeru; Hashimoto, Tokitada; Setoguchi, Toshiaki; Kim, Heuy Dong

    2015-04-01

    In the previous researches, it is known that the swirl flow in circular pipe causes the temperature separation. Recently, it is shown that the temperature separation occurs in a vortex chamber when compressed air are pumped into this device from the periphery. Especially, in a cavity installed in the periphery of the chamber, the highest temperature was observed. Therefore, it is expected that this device can be used as a heat source in the engineering field. In recent researches, the mechanism of temperature separation in vortex chamber has been investigated by some researchers. However, there are few researches for the effect of diameter and volume of vortex chamber, height of central rod and position of cavity on the temperature separation. Further, no detailed physical explanation has been made for the temperature separation phenomena in the vortex chamber. In the present study, the effects of chamber configuration and position of the cavity on temperature separation in the vortex chamber were investigated experimentally.

  14. In vitro study of the pulp chamber temperature rise during light-activated bleaching.

    PubMed

    Carrasco, Thaise Graciele; Carrasco-Guerisoli, Laise Daniela; Fröner, Izabel Cristina

    2008-01-01

    ). LED and LED-laser system did not differ significantly from each other regardless the temperature rise occurred with or without bleaching agent application. It may be concluded that during light-activated tooth bleaching, with or without the bleaching agent, halogen light promoted higher pulp chamber temperature rise than LED unit and LED-laser system. The tested light-curing units provided increases in the pulp chamber temperature that were compatible with pulpal health. PMID:19089234

  15. IN VITRO STUDY OF THE PULP CHAMBER TEMPERATURE RISE DURING LIGHT-ACTIVATED BLEACHING

    PubMed Central

    Carrasco, Thaise Graciele; Carrasco-Guerisoli, Laise Daniela; Fröner, Izabel Cristina

    2008-01-01

    significantly from each other regardless the temperature rise occurred with or without bleaching agent application. It may be concluded that during light-activated tooth bleaching, with or without the bleaching agent, halogen light promoted higher pulp chamber temperature rise than LED unit and LED-laser system. The tested light-curing units provided increases in the pulp chamber temperature that were compatible with pulpal health. PMID:19089234

  16. Uniform-Temperature Walls for Cloud Chambers

    NASA Technical Reports Server (NTRS)

    Fleischman, G.

    1985-01-01

    Flat heat pipes rapidly transfer heat to and from experimental volumes. Heat pipe vapor chamber carries heat to and from thermo electric modules. Critical surface acts as evaporator or condenser in cloud physics experiments. Used as walls of spaceborne atmospheric cloud chambers. On Earth, used as isothermal floors for environmental test chambers.

  17. Intra-pulpal temperature rise of different tooth types during dental bleaching supported by an Er,Cr:YSGG laser. A pilot study.

    PubMed

    Strakas, D; Tolidis, K; Koliniotou-Koumpia, E; Vanweersch, L; Franzen, R; Gutknecht, N

    2016-01-01

    The purpose of this pilot in vitro study was to evaluate the temperature increase in the pulp chamber of the teeth, during Er,Cr:YSGG bleaching, as well as to show which teeth are the most susceptible in terms of pulp temperature increase during laser-activated bleaching treatment. Although Er:YAG studies have been published on this subject, it is the first time Er,Cr:YSGG wavelength is tested. Fifteen teeth were tested--3 each of the following--(maxillary central incisors, lateral incisors, canines, premolars and mandibular incisors). The bleaching procedure comprised an Er,Cr:YSGG laser (2780 nm, Waterlase MD, Biolase, USA) and a yellow-coloured bleaching agent with a concentration of 38 % H2O2 (Power whitening, WHITEsmile GmbH, Germany). The tip used was a 6-mm long Z-type glass tip (MZ8) of a 800 μm diameter. Average output power was set to 1.25 W, pulse duration 700 μs (S-mode), whilst the pulse repetition rate was 10 Hz. The results showed that the most susceptible teeth in terms of pulp temperature increase were the lateral maxillary incisors and the mandibular incisors. The mean temperature increase on these teeth was 1.06 and 1.00 °C, respectively, on 60 s Er,Cr:YSGG-supported bleaching. PMID:26526961

  18. Regulation of pulpal blood flow

    SciTech Connect

    Kim, S.

    1985-04-01

    The regulation of blood flow of the dental pulp was investigated in dogs and rats anesthetized with sodium pentobarbital. Pulpal blood flow was altered by variations of local and systemic hemodynamics. Macrocirculatory blood flow (ml/min/100 g) in the dental pulp was measured with both the /sup 133/Xe washout and the 15-microns radioisotope-labeled microsphere injection methods on the canine teeth of dogs, to provide a comparison of the two methods in the same tooth. Microcirculatory studies were conducted in the rat incisor tooth with microscopic determination of the vascular pattern, RBC velocity, and intravascular volumetric flow distribution. Pulpal resistance vessels have alpha- and beta-adrenergic receptors. Activation of alpha-receptors by intra-arterial injection of norepinephrine (NE) caused both a reduction in macrocirculatory Qp in dogs and decreases in arteriolar and venular diameters and intravascular volumetric flow (Qi) in rats. These responses were blocked by the alpha-antagonist PBZ. Activation of beta-receptors by intra-arterial injection of isoproterenal (ISO) caused a paradoxical reduction of Qp in dogs. In rats, ISO caused a transient increase in arteriolar Qi followed by a flow reduction; arteriolar dilation was accompanied by venular constriction. These macrocirculatory and microcirculatory responses to ISO were blocked by the alpha-antagonist propranolol.

  19. Temperature and humidity control in indirect calorimeter chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-chamber, indirect calorimeter has been a part of the Environmental Laboratory at the U.S. Meat Animal Research Center (MARC) for over 25 yr. Corrosion of the animal chambers and unreliable temperature control forced either major repairs or complete replacement. There is a strong demand for...

  20. Kinetics of pulpal temperature rise during light curing of 6 bonding agents from different generations, using light emitting diode and quartz-tungsten-halogen units: An in-vitro simulation

    PubMed Central

    Khaksaran, Najmeh Khatoon; Kashi, Tahereh Jafarzadeh; Rakhshan, Vahid; Zeynolabedin, Zahra Sadat; Bagheri, Hossein

    2015-01-01

    Background: Application of bonding agents (BA) into deep cavities and light curing them might increase pulpal temperature and threaten its health. The purpose of this study was to evaluate temperature rise of pulp by light curing six BA using two different light curing units (LCU), through a dent in wall of 0.5 mm. Materials and Methods: This in vitro experiment was carried out on 96 slices of the same number of human third molars (6 BAs × 2 LCUs × 8 specimens in each group). There were 6 groups of BAs: N Bond, G-Bond, OptiBond XTR, Clearfil SE, Adper Single Bond 2 and V Bond. Each group of BA (n = 16) had two subgroups of light emitting diode (LED) and quartz-tungsten-halogen light cure units (n = 8). Each of these 16 specimens were subjected to light emitting for 20 s, once without any BAs (control) and later when a BA was applied to surface of disk. Temperature rises in 140 s were evaluated. Their mean temperature change in first 20 s were calculated and analyzed using two-way repeated-measures and one-way analysis of variance (ANOVA) and Tukey (α = 0.05). Furthermore rate of temperature increase was calculated for each material and LCU. Results: Minimum and maximum temperature rises in all subgroups were 1.7 and 2.8°C, respectively. Repeated measures ANOVA showed that both of adhesive and LCU types had significant effect on temperature rise after application of adhesives. Tukey post-hoc analysis showed Clearfil SE showed significantly higher temperature rise in comparison with Adper Single bond 2 (P = 0.047) and N Bond (P = 0.038). Temperature rose in a linear fashion during first 30-40 s and after that it was non-linear. Conclusion: 20 s of light curing seems safe for pulpal health (with critical threshold of 5.5°C). However, in longer durations and especially when using LED units, the process should be broken to two sessions. PMID:25878684

  1. Autofluorescence of healthy and inflamed pulpal tissues: photodynamic diagnosis of pulpal tissue

    NASA Astrophysics Data System (ADS)

    Ebihara, Arata; Kawashima, Nobuyuki; Saegusa, Hidetoshi; Anjo, Tomoo; Suda, Hideaki

    2005-03-01

    Autofluorescence of healthy and inflamed human pulpal tissues was observed by confocal laser microscopy. In this preliminary study, photodynamic diagnosis (PDD) was applied to diagnose pulpal disease. The ability to accurately diagnose pulpal pathology prior to pulpectomy would be very beneficial. Clinically, however, we are unable to perform biopsy to detect pathological changes. Therefore, this study was performed using healthy, acutely and chronically inflamed human pulpal tissues to detect pathological changes in pulpal tissues. Following excision, pulpal tissues were rapidly frozen and standard cryosections were prepared. Autofluorescence of pulpal tissues was observed using a confocal laser microscope to examine whether there were any differences in autofluorescence intensities between healthy and inflamed pulpal tissues. Several combinations of excitation and detection wavelengths were tested to observe autofluorescence from pulpal tissues; the excitation wavelengths ranged from 488nm to 633nm, and the detection wavelengths were longer than 505 nm. Autofluorescence was detected in both healthy and inflamed groups. With this technique, it may be possible to diagnose pulpal pathology without biopsy, and might be applicable to photodynamic diagnosis (PDD) and photodynamic therapy (PDT) in root canal treatment.

  2. A Temperature-Controlled Chamber Based on Vortex Cooling

    SciTech Connect

    Krider, John; Nguyen, Hogan; /Fermilab

    2007-11-01

    We describe the construction and performance of a temperature-controlled chamber, based on a 'vortex' cooler. The chamber is capable of operation between room temperature and -42 C. The only nontrivial infrastructure requirement is dry compressed gas at 100 psi and 8 cfm. The chamber is economical, easy to operate and to build using commercially available parts. Since the refrigerant is compressed air, the chamber has minimal environmental impact. It does not generate mechanical vibrations nor electrical noise. It is suitable for testing electronically sensitive and low-power electronics at cold temperatures. We measured the reserve cooling capacity of the cold plate to be 17 watts at -27 C. At the limiting temperature of -42 C, reserve cooling power reduces to zero.

  3. Damage Diagnosis for High Temperature Coke-oven Chamber Walls

    NASA Astrophysics Data System (ADS)

    Sugiura, Masato; Sakaida, Michitaka; Fujikake, Yohichi; Irie, Keisuke

    Metallurgical coke is needed as reducing reagent and energy source in blast furnaces. Most of coke ovens in Japan have been working over 30 years and have become gradually decrepit. A coke oven consists of many coking chambers, and each chamber is 6 m high, 16 m long and 0.4m wide. Uneven damage at the chamber-wall surface such as brick erosion and carbon deposition disturbs production because the coke is pushed horizontally when discharged from the chamber. To diagnose the chamber wall which is constantly sustained at a high temperature, we have developed a water-cooling heat-resistance probe. Line scan cameras mounted in the probe obtain thermal images of the entire chamber-wall surfaces with high resolution. In addition, to measure topographical information of the wall, a laser light-section method combined with line-scan-camera imaging has been considered. It is emphasized that the diagnosis probe works under enormously severe conditions, such as at a temperature of over 1000°C and inside a width of only 0.4m. Clarifying the appearance of chamber-wall damages in operating aged coke ovens, we proposed the index relating unevenness of a chamber-wall surface to pushing load. The index is utilized for the guidance enabling effective repairs of damaged oven walls.

  4. Optical Pressure-Temperature Sensor for a Combustion Chamber

    NASA Technical Reports Server (NTRS)

    Wiley, John; Korman, Valentin; Gregory, Don

    2008-01-01

    A compact sensor for measuring temperature and pressure in a combusti on chamber has been proposed. The proposed sensor would include two optically birefringent, transmissive crystalline wedges: one of sapph ire (Al2O3) and one of magnesium oxide (MgO), the optical properties of both of which vary with temperature and pressure. The wedges wou ld be separated by a vapor-deposited thin-film transducer, which wou ld be primarily temperaturesensitive (in contradistinction to pressur e- sensitive) when attached to a crystalline substrate. The sensor w ould be housed in a rugged probe to survive the extreme temperatures and pressures in a combustion chamber.

  5. Gender determination from pulpal tissue

    PubMed Central

    Khorate, Manisha M.; Dhupar, Anita; Ahmed, Junaid; Dinkar, Ajit D.

    2014-01-01

    Objective: To evaluate the diagnostic performance of X (Barr body [BB]) and Y (F body [FB]) chromosomes observed in dental pulp tissue for gender determination of an individual. Materials and Methods: The study was carried out on 100 teeth (50 male and 50 female), which were indicated for extraction. The teeth were sectioned at various intervals (within 12 h to 49 days post-extraction), and the pulpal tissue was obtained. Two slides for each pulp tissue were prepared, one for 5% Quinacrine dihydrochloride stain (FB) and the other for Hemotoxylin and Eosin stain (BB). The slides were then observed under the fluorescent microscope for FB and under the light microscope for the BB respectively. Results: Gender determination from human pulp is possible up to 7 weeks. The percentage of FB and BB decrease gradually as the time interval increases. Further, an equation was derived from the data based on the canonical discriminant function coefficients. Conclusion: The determination of gender based on a joint search for the presence or absence of X (BB) and Y (FB) Chromosome is a reliable and cost-effective technique. PMID:25125918

  6. HPXe ionization chambers for γ spectrometry at room temperature

    NASA Astrophysics Data System (ADS)

    Ottini-Hustache, S.; Monsanglant-Louvet, C.; Haan, S.; Dmitrenko, V.; Grachev, V.; Ulin, S.

    2004-01-01

    High pressure xenon (HPXe) ionization chambers exhibit many characteristics which make them particularly suitable for industrial γ spectrometry at room or higher temperature. The use of a gas as detection medium allows one to reach very large effective volumes and makes these chambers relatively insensitive to radiation damage. Further, the high atomic number of xenon ( Z=54) enhances the total absorption of incident photons and provides, combined to high pressure, a good enough detection efficiency with respect to solid state detectors. Furthermore, such ionization chambers with Frisch grid appear to be very stable over wide periods (e.g. a research prototype has been used aboard MIR orbital station for several years) and temperature range (up to 180°), without maintenance. The characteristics of different prototypes are presented. Their detection efficiency and energy resolution are studied as a function of incident γ ray energy. New developments in electronics and signal processing are also investigated to improve their performances.

  7. Pulpal Effects of Enamel Ablation With a Microsecond Pulsed λ=9.3-μm CO2 Laser

    PubMed Central

    Staninec, Michal; Darling, Cynthia L.; Goodis, Harold E.; Pierre, Daniel; Cox, Darren P.; Fan, Kenneth; Larson, Michael; Parisi, Renaldo; Hsu, Dennis; Manesh, Saman K.; Ho, Chi; Hosseini, Mehran; Fried, Daniel

    2011-01-01

    Background and Objectives In vitro studies have shown that CO2 lasers operating at the highly absorbed 9.3 and 9.6-μm wavelengths with a pulse duration in the range of 10–20-microsecond are well suited for the efficient ablation of enamel and dentin with minimal peripheral thermal damage. Even though these CO2 lasers are highly promising, they have yet to receive FDA approval. Clinical studies are necessary to determine if excessive heat deposition in the tooth may have any detrimental pulpal effects, particularly at higher ablative fluencies. The purpose of this study was to evaluate the pulpal safety of laser irradiation of tooth occlusal surfaces under the conditions required for small conservative preparations confined to enamel. Study Design/Materials and Methods Test subjects requiring removal of third molar teeth were recruited and teeth scheduled for extraction were irradiated using a pulsed CO2 laser at a wavelength of 9.3 μm operating at 25 or 50 Hz using a incident fluence of 20 J/cm2 for a total of 3,000 laser pulses (36 J) for both rates with water cooling. Two control groups were used, one with no treatment and one with a small cut made with a conventional high-speed hand-piece. No anesthetic was used for any of the procedures and tooth vitality was evaluated prior to treatment by heat, cold and electrical testing. Short term effects were observed on teeth extracted within 72 hours after treatment and long term effects were observed on teeth extracted 90 days after treatment. The pulps of the teeth were fixed with formalin immediately after extraction and subjected to histological examination. Additionally, micro-thermocouple measurements were used to estimate the potential temperature rise in the pulp chamber of extracted teeth employing the same irradiation conditions used in vivo. Results Pulpal thermocouple measurements showed the internal temperature rise in the tooth was within safe limits, 3.3±4°C without water cooling versus 1.7±6

  8. Real-Time Analysis of Temperature Changes in Composite Increments and Pulp Chamber during Photopolymerization

    PubMed Central

    Kim, Ryan Jin-Young; Lee, In-Bog; Yoo, Jin-Young; Park, Su-Jung; Kim, Sin-Young; Yi, Young-Ah; Hwang, Ji-Yun; Seo, Deog-Gyu

    2015-01-01

    Objective. The aim of this study was to evaluate the temperature change at various sites within the composite and on the pulpal side of dentin during polymerization of two composite increments. Materials and Methods. Class I cavities prepared in third molars were restored in two composite increments (n = 5). Temperatures were measured for 110 s using eight thermocouples: bottom center of cavity (BC), top center of 1st increment (MC), top center of 2nd increment (TC), bottom corner of cavity (BE), top corner of 1st increment (ME), top corner of 2nd increment (TE), pulpal side of dentin (PD), and center of curing light guide tip (CL). Results. Maximum temperature values (°C) measured during polymerization of 1st increment were MC (59.8); BC (52.8); ME (51.3); CL (50.7); BE (48.4); and PD (39.8). Maximum temperature values during polymerization of 2nd increment were TC 58.5; TE (52.6); MC (51.7); CL (50.0); ME (48.0); BC (46.7); BE (44.5); and PD (38.8). Conclusion. Temperature at the floor of the cavity was significantly higher during polymerization of 1st increment compared to 2nd increment. Temperature rise was higher at the center than at the corner and at the top surface than at the bottom surface of each increment. PMID:26557716

  9. Chamber for dielectric studies at temperatures to 2100K

    SciTech Connect

    Bozhko, I.V.

    1985-08-01

    A cylindrical chamber of aluminum oxide for electrophysical studies of gaseous and solid dielectrics at high temperatures is described. The gas pressure in the chamber is atmospheric. An easily ionized admixture in the form of vapor of an alkali metal (K or Na) can be introduced into the gas. A high temperature is produced by an electric resistance furnace that allows heating to 2100 degrees K in an oxidizing medium without special shielding means. The use of materials such as A1/sub 2/O/sub 3/ and PtRh alloys makes it possible to conduct research that minimizes the level of contamination of the medium under study by vapors of the elements of the apparatus.

  10. Molecular signaling and pulpal nerve development.

    PubMed

    Fried, K; Nosrat, C; Lillesaar, C; Hildebrand, C

    2000-01-01

    The purpose of this review is to discuss molecular factors influencing nerve growth to teeth. The establishment of a sensory pulpal innervation occurs concurrently with tooth development. Epithelial/mesenchymal interactions initiate the tooth primordium and change it into a complex organ. The initial events seem to be controlled by the epithelium, and subsequently, the mesenchyme acquires odontogenic properties. As yet, no single initiating epithelial or mesenchymal factor has been identified. Axons reach the jaws before tooth formation and form terminals near odontogenic sites. In some species, local axons have an initiating function in odontogenesis, but it is not known if this is also the case with mammals. In diphyodont mammals, the primary dentition is replaced by a permanent dentition, which involves a profound remodeling of terminal pulpal axons. The molecular signals underlying this remodeling remain unknown. Due to the senescent deterioration of the dentition, the target area of tooth nerves shrinks with age, and these nerves show marked pathological-like changes. Nerve growth factor and possibly also brain-derived neurotrophic factor seem to be important in the formation of a sensory pulpal innervation. Neurotrophin-3 and -4/5 are probably not involved. In addition, glial cell line-derived neurotrophic factor, but not neurturin, seems to be involved in the control of pulpal axon growth. A variety of other growth factors may also influence developing tooth nerves. Many major extracellular matrix molecules, which can influence growing axons, are present in developing teeth. It is likely that these molecules influence the growing pulpal axons. PMID:11021633

  11. Relation between pulpal neuropeptides and dental caries

    PubMed Central

    Kangarlou Haghighi, Ali; Nafarzadeh, Shima; Shantiaee, Yazdan; Naseri, Mandana; Ahangari, Zohreh

    2010-01-01

    INTRODUCTION: Dental pulp has neural fibers that produce neuropeptides like Substance P (SP) and calcitonin gene-related peptide (CGRP). The inflammation of dental pulp can lead to an increase amount of SP and CGRP release, especially in symptomatic irreversible pulpitis. Therefore, it can be assumed that neuropeptides have some role in the progression of inflammation of the dental pulp. The aim of this study was to determine the relation between the presence and concentration of neuropeptides in dental pulps of carious teeth caries. MATERIALS AND METHODS: For this purpose, pulpal tissues were collected from 40 teeth (20 carious and 20 intact). Pulpal samples were cultured for 72 hours. ELISA reader was used for the detection of SP and CGRP in supernatant fluids. Statistical analysis was made by Mann-Whitney U and Chi square tests. RESULTS: SP and CGRP were present in 65% and 20% of inflamed pulpal samples, respectively and 40% and 5% of normal pulpal samples, respectively. Level of SP was significantly higher in inflamed pulp samples compared to intact pulps; however, there was no statistical difference when the other groups and neuropeptides were compared. The mean concentration of SP in normal pulps was 3.4 times greater than that of CGRP; interestingly in inflamed pulps the concentration of SP was 22.3 times greater than CGRP. CONCLUSION: We can conclude that in inflamed dental pulps, the concentration of SP is higher than CGRP. It can be hypothesized that CGRP has less effect on the inflammatory changes of dental pulps. PMID:24778684

  12. Light-induced fluorescence for pulpal diagnosis

    NASA Astrophysics Data System (ADS)

    Ebihara, Arata; Liaw, Lih-Huei L.; Krasieva, Tatiana B.; Wilder-Smith, Petra B. B.

    2001-04-01

    A direct non-histological means of pulpal diagnosis remains elusive to clinical practice. Clinical vitality testing remains limited to electric, thermal criteria, or laser Doppler flowmetry. The goal of these investigations was to determine the feasibility of using light-induced fluorescence as a non-invasive modality for pulpal evaluation. Such a capability would, for example, permit expanded use of pulpotomy/pulpectomy techniques. Clinically healthy and diseased human extirpated pulpal tissues were used in this study. After excision, they were rapidly frozen and standard cryosections prepared. Measurement of tissue excitation/emission characteristics was performed using spectrographic analysis. A low-light level fluorescence microscopy system was then used to image autofluorescence localization and intensity at optimal excitation/detection parameters. Excitation/detection parameters used in this study included 405/605, 405/635, 405/670, 440/550, and 440/635. Autofluorescence intensities in healthy tissues were significantly stronger than those in diseased tissues at optimal parameters. It is postulated that autofluorescence characteristics are related to pathology- related structural changes in the pulp. This work provides the basis for further investigation into the relation between autofluorescence, histology and clinical symptoms.

  13. Thermistors Used in Climatic Chamber at High Temperature and Humidity

    NASA Astrophysics Data System (ADS)

    van Geel, J. L. W. A.; Bosma, R.; van Wensveen, J.; Peruzzi, A.

    2015-03-01

    In 2011, VSL initiated the development of a facility for a relative humidity between and for calibrating high-temperature relative humidity sensors at pressures other than atmospheric. The setup for calculating the relative humidity uses the dew-point temperature, measured by a chilled mirror hygrometer, and the temperature distribution in the chamber, measured by a series of thermistors. This paper describes the results of thermal tests performed on the thermistors to ensure that they meet the requirements of the humidity calibration facility. Different types of thermistors were evaluated up to , and the selected type showed a short-term drift of less than 2 mK. Exposure of these thermistors to temperatures up to gave an initial hysteresis of 40 mK, but after this initial hysteresis, the hysteresis, over the range from up to , was less than 10 mK. Use of a digital multimeter, with a low-power option, limited the self-heating of the thermistors, over the range from up to , to less than 5 mK. During use in the new setup, the thermistors were exposed to changing humidities between 1 %Rh and 90 %Rh and temperatures up to , showing drifts of less than 10 mK.

  14. Comparison of temperature rise in pulp chamber during polymerization of materials used for direct fabrication of provisional restorations: An in-vitro study

    PubMed Central

    Khajuria, Rajat R.; Madan, Ravi; Agarwal, Swatantra; Gupta, Reecha; Vadavadgi, Sunil V.; Sharma, Vikas

    2015-01-01

    Objective: The purpose is to compare temperature rise in the pulp chamber during fabrication of provisional crowns using different materials and on different types of teeth using direct technique. Materials and Methods: An extracted, sound, caries free maxillary central incisor and a mandibular molar were selected for the study and crown preparations of all ceramic and all metal were done on central incisor and mandibular molar, respectively. Materials tested were DPI tooth molding self-curing material and protemp-4. Addition silicone putty was used as a matrix and 80 provisional crowns were fabricated, of which 40 were on central incisor and 40 on mandibular molar. Depending on the type of material used, they were further divided into two subgroups: Each comprising 20 provisional crowns. Temperature readings were recorded using K type of thermocouple with 0.1°C precision digital thermometer. Statistical Analysis Used: Analysis of variance, Tukey honest significant difference and Kruskall–Wallis H-test. Results: Statistically significant difference exists between two materials tested on the basis of peak temperature achieved and time taken by a particular material to reach peak temperature. Peak temperature achieved was highest for provisional crowns with DPI tooth molding self-curing material on maxillary central incisor (40.39 + 0.46), followed by DPI tooth molding self-curing material on mandibular molar (40.03 + 0.32), protemp-4 on maxillary central incisor (39.46 + 0.26) and least with protemp-4 on mandibular molar (39.09 + 0.33). The time taken to reach peak temperature was almost double in DPI tooth molding self-curing material (5 min) than in protemp-4. Conclusion: Polymethyl methacrylate resin produced higher intra-pulpal rise when compared to newer generation bis-acrylic composite. PMID:26038649

  15. Monkey pulpal responses to conventional and adhesive luting cements.

    PubMed

    Inokoshi, S; Fujitani, M; Otsuki, M; Sonoda, H; Kitasako, Y; Shimada, Y; Tagami, J

    1998-01-01

    Monkey pulpal responses to metal inlays luted with a combination of an adhesive resin and luting composite and conventional dental cements were histopathologically evaluated. Initial pulpal responses caused by re-exposure of the cut dentin surfaces and luting procedure under hydraulic pressure subsided at 90 days after final cementation. There was no significant difference among pulpal reactions to conventional dental cements and a combination of an adhesive resin and luting composite. The adhesive resin coating of freshly cut dentinal walls/floors immediately after cavity preparation seems to provide protection for the dentin and pulp in indirect restorations requiring temporary sealing. PMID:9610329

  16. Methyl bromide emissions from a covered field: III. Correcting chamber flux for temperature

    SciTech Connect

    Yates, S.R.; Gan, J.; Ernst, F.F.; Wang, D.

    1996-07-01

    An experiment was conducted to investigate the environmental fate and transport of methyl bromide (MeBr) in agricultural systems. Part of this experiment involved the use of three flow-through chambers to estimate the MeBr flux through a sheet of clear polyethylene plastic covering the field. Using the chamber data, the total mass lost to the atmosphere was estimated to be 96% of the applied mass, and the results were highly variable between chambers (i.e., standard deviation of 298 kg or 35%). The air temperature inside the chamber was found to be much higher than the air temperature outside and was highly correlated with the diurnal variation in incoming solar radiation. Since the diffusion through polyethylene film was found to be strongly dependent on the temperature, a method was developed to correct the chamber flux density data for enhanced diffusion caused by increases in the temperature inside the chamber. After correcting for temperature, the estimated total MeBr emission was reduced to approximately 59% (21% standard deviation) of the applied amount, which is about 5% less than was measured using other methods. When chambers are used to measure volatilization of MeBr or other fumigants from fields covered with a sheet of polyethylene plastic, the chambers should be designed to minimize internal heating or some method should be used to correct the volatilization rate for the effects of temperature. 16 refs., 5 figs., 1 tab.

  17. Constructal approach to bio-engineering: the ocular anterior chamber temperature

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto; Grisolia, Giulia; Dolcino, Daniela; Astori, Maria Rosa; Massa, Eugenio; Ponzetto, Antonio

    2016-08-01

    The aim of this work was to analyse the pressure inside the eyes anterior chamber, namedintraocular pressure (IOP), in relation to the biomechanical properties of corneas. The approach used was based on the constructal law, recently introduced in vision analysis. Results were expressed as the relation between the temperature of the ocular anterior chamber and the biomechanical properties of the cornea. The IOP, the elastic properties of the cornea, and the related refractive properties of the eye were demonstrated to be dependent on the temperature of the ocular anterior chamber. These results could lead to new perspectives for experimental analysis of the IOP in relation to the properties of the cornea.

  18. Constructal approach to bio-engineering: the ocular anterior chamber temperature

    PubMed Central

    Lucia, Umberto; Grisolia, Giulia; Dolcino, Daniela; Astori, Maria Rosa; Massa, Eugenio; Ponzetto, Antonio

    2016-01-01

    The aim of this work was to analyse the pressure inside the eyes anterior chamber, namedintraocular pressure (IOP), in relation to the biomechanical properties of corneas. The approach used was based on the constructal law, recently introduced in vision analysis. Results were expressed as the relation between the temperature of the ocular anterior chamber and the biomechanical properties of the cornea. The IOP, the elastic properties of the cornea, and the related refractive properties of the eye were demonstrated to be dependent on the temperature of the ocular anterior chamber. These results could lead to new perspectives for experimental analysis of the IOP in relation to the properties of the cornea. PMID:27492652

  19. Constructal approach to bio-engineering: the ocular anterior chamber temperature.

    PubMed

    Lucia, Umberto; Grisolia, Giulia; Dolcino, Daniela; Astori, Maria Rosa; Massa, Eugenio; Ponzetto, Antonio

    2016-01-01

    The aim of this work was to analyse the pressure inside the eyes anterior chamber, namedintraocular pressure (IOP), in relation to the biomechanical properties of corneas. The approach used was based on the constructal law, recently introduced in vision analysis. Results were expressed as the relation between the temperature of the ocular anterior chamber and the biomechanical properties of the cornea. The IOP, the elastic properties of the cornea, and the related refractive properties of the eye were demonstrated to be dependent on the temperature of the ocular anterior chamber. These results could lead to new perspectives for experimental analysis of the IOP in relation to the properties of the cornea. PMID:27492652

  20. Determining Temperature Differential to Prevent Hardware Cross-Contamination in a Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    Hughes, David

    2013-01-01

    When contamination-sensitive hardware must be tested in a thermal vacuum chamber, cross-contamination from other hardware present in the chamber, or residue from previous tests, becomes a concern. Typical mitigation strategies involve maintaining the temperature of the critical item above that of other hardware elements at the end of the test. A formula for relating the pumping speed of a chamber, the surface area of contamination sources, and the temperatures of the chamber, source, and contamination-sensitive items has been developed. The formula allows the determination of a temperature threshold about which contamination will not condense on the sensitive items. It defines a parameter alpha that is the fraction given by (contaminant source area)/[chamber pumping speed (time under vacuum) 0.5]. If this parameter is less than 10(exp -6), cross-contamination from common spacecraft material will not occur when the sensitive hardware is at the same temperature as the source of contamination (The chamber is isothermal within 5 C.). Knowing when it becomes safe to have the hardware isothermal permits faster and easier thermal transitions when compared with maintaining an arbitrary temperature differential between parts. Furthermore, the standard temperature differential may not be adequate under some conditions (alpha>10(exp -4)).

  1. Acoustic temperature profile measurement technique for large combustion chambers

    NASA Technical Reports Server (NTRS)

    Venkateshan, S. P.; Shakkottai, P.; Kwack, E. Y.; Back, L. H.

    1989-01-01

    Measurement of times of flight of sound waves can be used to determine temperatures in a gas. This paper describes a system, based on this principle, that is capable of giving the temperature profile in a nonisothermal gas volume, for example, prevalent in a large furnace. The apparatus is simple, rugged, accurate, and capable of being automated for process control applications. It is basically an acoustic waveguide where the outside temperature profile is transferred to a chosen gas contained inside the guide.

  2. Acoustic temperature profile measurement technique for large combustion chambers

    SciTech Connect

    Venkateshan, S. P.; Shakkottai, P.; Kwack, E. Y.; Back, L. H.

    1989-05-01

    Measurement of times of flight of sound waves can be used to determinetemperatures in a gas. This paper describes a system, based on this principle,that is capable of giving the temperature profile in a nonisothermal gasvolume, for example, prevalent in a large furnace. The apparatus is simple,rugged, accurate, and capable of being automated for process controlapplications. It is basically an acoustic waveguide where the outsidetemperature profile is tranferred to a chosen gas contained inside theguide.

  3. Pulpal inflammatory responses following non-carious class V restorations.

    PubMed

    About, I; Murray, P E; Franquin, J C; Remusat, M; Smith, A J

    2001-01-01

    The effects of inflammatory activity following surgical intervention can injure pulp tissues; in severe cases it can lead to pulpal complications. With this article, the authors report on the effects of cavity preparation and restoration events and how they can interact together to reduce or increase the severity of pulpal inflammatory activity in 202 restored Class V cavities. Although some inflammatory activity was observed in the absence of bacteria, the severity of pulpal inflammatory activity was increased when cavity restorations became infected. Zinc oxide eugenol and resin-modified glass ionomer cement prevented bacterial microleakage in cavity restorations, with no severe inflammatory activity observed with these materials. Bacteria were observed in cavities restored with enamel bonding resin and adhesive bonded composites and were associated with severe grades of inflammatory activity. The cavity remaining dentin thickness influenced the grade of inflammatory activity. In the absence of infection, the grade of inflammatory activity decreased after 20 weeks post-operatively. In the presence of infection, the grade of pulpal inflammation remained stable until a minimum of 30 weeks had elapsed. PMID:11504432

  4. Measurement and prediction of the heat flow and temperature level in a precombustion chamber diesel

    SciTech Connect

    Fahmy, A.S.; Radwan, M.S.; Shams, A.M.; Raafat, N.M.

    1984-01-01

    Heat flux and temperature mapping were carried out in necessary detail in the combustion chamber of a pepper-pot type pre-combustion chamber diesel engine. A test set up was specifically prepared for this purpose in which heat fluxes were measured by specially designed traversing thermo couples, four of which were installed across the cylinder head and five were fitted along the cylinder liner. In combustion chamber locations not subjected to very high heat flows viz pre-combustion chamber tip, fuel-injection nozzle tip, exhaust valve etc. but their temperature level is the all-important factor in service, fixed microthermo couples were embedded in the metal as close as possible to the gas face of the component. The widest possible variation in load and speed was applied and it was found that the predominant factor affecting the heat flux and temperature level was the fueling rate unit piston area, effected by engine load and/or speed. Qualitative evidence suggests that piston heat fluxes follow the same pattern of that in the cylinder head. Heat flux and temperature level correlations were developed for the various combustion chamber components. Heat fluxes and metal temperatures seemed to follow the direction and intensity of air swirl. Thus they proved to be considerably higher in this engine in comparison with compression-swirl or induction swirl engines. As a result, pre-combustion chamber engines will be more difficult to uprate than comet or direct-injection engines. Contrary to most other types of engines, the centre region of the cylinder head which encompasses the valve bridge did not exhibit the highest thermal load. In fact the outer locations of bore are the critical zones in design.

  5. Temperature changes in the pulp chamber during dentin ablation with Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Zhang, Xianzeng; Zhao, Haibin; Zhan, Zhenlin; Guo, Wenqing; Xie, Shusen

    2012-12-01

    To examine the temperature changes in the pulp chamber during cavity preparation in dentin with the Er:YAG laser (2940 nm), a total 20 intact premolars teeth were divided into 4 groups for dentin ablation with different radiant exposures at 4Hz and 8Hz with and without water spray. A K-type thermocouple was used to monitor the temperature changes in pulp chamber during laser treatment. The total time of irradiation was 70 sec. the water spray rate was 3 mL/min. It showed that maximum temperature rise increases with the increasing of radiant exposure and pulse repetition rate and the additional water cooling during laser ablation can significantly reduce the temperature rise in pulp chamber which will benefit to avoid or reduce thermal damage to tooth structure and dental pulp. The highest rise of temperature in the pulp was achieved with 20 J/cm2 and 8 Hz (19.83°C ). For all sample without water spray, the rise of temperature was exceed 5 °C . In contrast, with water spray, the temperature rise in the pulp can be firmly controlled under 1°C. The results also indicated that ablation rate and efficiency can be enhanced by increasing the incident radiant exposure and pulse repetition rate, which simultaneously producing more heat accumulation in dental tissue and causing thermal damage to dental tissue. By applying an additional water spray, thermal damage can be significantly reduced in clinical application.

  6. The Chamber for Studying Rice Response to Elevated Nighttime Temperature in Field

    PubMed Central

    Chen, Song; Zheng, Xi; Wang, Dangying; Xu, Chunmei; Laza, Ma. Rebecca C.; Zhang, Xiufu

    2013-01-01

    An in situ temperature-controlled field chamber was developed for studying a large population of rice plant under different nighttime temperature treatments while maintaining conditions similar to those in the field during daytime. The system consists of a pipe hoop shed-type chamber with manually removable covers manipulated to provide a natural environment at daytime and a relatively stable and accurate temperature at night. Average air temperatures of 22.4 ± 0.3°C at setting of 22°C, 27.6 ± 0.4°C at 27°C, and 23.8 ± 0.7°C ambient conditions were maintained with the system. No significant horizontal and vertical differences in temperature were found and only slight changes in water temperatures were observed between the chambers and ambient conditions at 36 days after transplanting. A slight variation in CO2 concentration was observed at the end of the treatment during the day, but the 10-μmol CO2 mol−1 difference was too small to alter plant response. The present utilitarian system, which only utilizes an air conditioner/heater, is suitable for studying the effect of nighttime temperature on plant physiological responses with minimal perturbation of other environmental factors. At the same time, it will enable in situ screening of many rice genotypes. PMID:24089603

  7. Note: A versatile mass spectrometer chamber for molecular beam and temperature programmed desorption experiments

    NASA Astrophysics Data System (ADS)

    Tonks, James P.; Galloway, Ewan C.; King, Martin O.; Kerherve, Gwilherm; Watts, John F.

    2016-08-01

    A dual purpose mass spectrometer chamber capable of performing molecular beam scattering (MBS) and temperature programmed desorption (TPD) is detailed. Two simple features of this design allow it to perform these techniques. First, the diameter of entrance aperture to the mass spectrometer can be varied to maximize signal for TPD or to maximize angular resolution for MBS. Second, the mass spectrometer chamber can be radially translated so that it can be positioned close to the sample to maximize signal or far from the sample to maximize angular resolution. The performance of this system is described and compares well with systems designed for only one of these techniques.

  8. Note: A versatile mass spectrometer chamber for molecular beam and temperature programmed desorption experiments.

    PubMed

    Tonks, James P; Galloway, Ewan C; King, Martin O; Kerherve, Gwilherm; Watts, John F

    2016-08-01

    A dual purpose mass spectrometer chamber capable of performing molecular beam scattering (MBS) and temperature programmed desorption (TPD) is detailed. Two simple features of this design allow it to perform these techniques. First, the diameter of entrance aperture to the mass spectrometer can be varied to maximize signal for TPD or to maximize angular resolution for MBS. Second, the mass spectrometer chamber can be radially translated so that it can be positioned close to the sample to maximize signal or far from the sample to maximize angular resolution. The performance of this system is described and compares well with systems designed for only one of these techniques. PMID:27587173

  9. Altitude-chamber Performance of British Roll-royce Nene II Engine IV : Effect of Operational Variables on Temperature Distribution at Combustion-chamber Outlets

    NASA Technical Reports Server (NTRS)

    Huntley, Sidney C

    1950-01-01

    Temperature surveys were made at the combustion-chamber outlets of a British Rolls-Royce Nene II engine. The highest mean nozzle-vane and mean gas temperatures were found to occur at a radius approximately 75% of the nozzle-vane length from the inner ring of the nozzle-vane assembly. Variations in engine speed, jet-nozzle area, simulated altitude, and simulated flight speed altered the temperature level but did not materially affect the pattern of radial temperature distribution.

  10. The effect of small temperature gradients on flow in a continuous flow electrophoresis chamber

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H.; Snyder, R. S.

    1982-01-01

    Continuous flow electrophoresis employs an electric field to separate biological cells suspended in a flowing liquid buffer solution. Good separations based on differences in electrophoretic mobility are obtained only when a unidirectional flow is maintained. The desired flow has a parabolic structure in the narrow dimension of the chamber and is uniform acros the width, except near the edges where the no-slip condition prevails. However, because of buoyancy, very small laterall or axial temperature gradients deform the flow significantly. The results of experiments conducted with a specially instrumented chamber show the origin and structure of the buoyancy-driven perturbations. It is found that very small temperature gradients can disturb the flow significantly, as was predicted by earlier theoretical work.

  11. The dependence of aerosol formation in a plant chamber on temperature, UV radiation and relative humidity

    NASA Astrophysics Data System (ADS)

    Dal Maso, M.; Hohaus, T.; Kiendler-Scharr, A.; Kleist, E.; Mentel, Th. F.; Tillmann, R.; Wildt, J.

    2009-04-01

    The ongoing climate change is expected to raise air temperatures; this will have an effect on the vegetation and its emission pattern. Biogenic VOC emissions are temperature dependent, with increasing temperatures causing increasing emissions. Increased temperatures could also lead to increased occurrences of heat stress in plants, inducing changes in plant emission patterns. This has given rise to propositions for a feedback between vegetation and climate, with increasing temperatures causing increased aerosol loading, which in turn has a cooling effect. We have investigated the dependence on the aerosol production from plant emissions on various environmental factors, such as temperature, RH or UV intensity in the Jülich Aerosol Atmosphere Plant Chamber setup (JPAC). Higher temperatures in the plant chamber lead to higher emissions; this also lead to higher particle number production as well as increased growth rates. Relative humidity and UV irradiation were also shown to influence particle formation; the possible chemical and physical pathways causing this will be discussed. We will also discuss the relative roles of formation rate and growth rate enhancements in producing cloud condensation nuclei utilising a simple aerosol dynamics modelling approach.

  12. Raman measurements of substrate temperature in a molecular beam epitaxy growth chamber

    NASA Astrophysics Data System (ADS)

    Hutchins, T.; Nazari, M.; Eridisoorya, M.; Myers, T. M.; Holtz, M.

    2015-01-01

    A method is described for directly measuring the temperature of a substrate in a molecular-beam epitaxy (MBE) growth system. The approach relies on the establishment of the temperature dependence of Raman-active phonons of the substrate material using independently known calibration points across the range of interest. An unknown temperature in this range is then determined based on the Raman peak position with the substrate in situ the MBE chamber. The apparatus relies on conventional optics and Raman components. Shifting and broadening of the Raman spectrum are described based on the effects of thermal expansion and anharmonic decay. The choice of reference temperature is discussed. The method is qualified by examining the substrate temperature dependence, relative to that of a standard thermocouple, during a commonly used ramp procedure. Both temperature difference and time lag are obtained.

  13. Raman measurements of substrate temperature in a molecular beam epitaxy growth chamber

    SciTech Connect

    Hutchins, T.; Nazari, M.; Eridisoorya, M.; Myers, T. M.; Holtz, M.

    2015-01-15

    A method is described for directly measuring the temperature of a substrate in a molecular-beam epitaxy (MBE) growth system. The approach relies on the establishment of the temperature dependence of Raman-active phonons of the substrate material using independently known calibration points across the range of interest. An unknown temperature in this range is then determined based on the Raman peak position with the substrate in situ the MBE chamber. The apparatus relies on conventional optics and Raman components. Shifting and broadening of the Raman spectrum are described based on the effects of thermal expansion and anharmonic decay. The choice of reference temperature is discussed. The method is qualified by examining the substrate temperature dependence, relative to that of a standard thermocouple, during a commonly used ramp procedure. Both temperature difference and time lag are obtained.

  14. Modeling of temperature fields in the working chamber of the process furnace for REE synthesis

    NASA Astrophysics Data System (ADS)

    Kerbel, B. M.; Yu, Ageev A.; Yu, Payusov A.; Katsnelson, L. M.; Tereshchenko, E. V.; Verkhoturova, V. V.

    2016-02-01

    The results of mathematical modeling of temperature fields in the working chamber of the process furnace for special purposes are shown. Studied laboratory furnace is test equipment, which is used for practicing the stages of the technological process of continuous solid-phase synthesis of nanopowders of various purpose, such as obtaining of luminophore powders with rare earth elements oxides in its composition. Mathematical model adequacy is tested empirically

  15. Stem Cell Transplantation for Pulpal Regeneration: A Systematic Review.

    PubMed

    Fawzy El-Sayed, Karim M; Jakusz, Kimberley; Jochens, Arne; Dörfer, Christof; Schwendicke, Falk

    2015-10-01

    For treating pulpal pathological conditions, pulpal regeneration through transplanted stem/progenitor cells might be an alternative to conventional root canal treatment. A number of animal studies demonstrated beneficial effects of stem/progenitor cell transplantation for pulp-dentin complex regeneration, that is, pulpal tissue, neural, vascular, and dentinal regeneration. We systematically reviewed animal studies investigating stem/progenitor cell-mediated pulp-dentin complex regeneration. Studies quantitatively comparing pulp-dentin complex regeneration after transplantation of stem/progenitor cells versus no stem/progenitor cell transplantation controls in intraoral in vivo teeth animal models were analyzed. The following outcomes were investigated: regenerated pulp area per root canal total area, capillaries per total surface, regenerated dentinal area per total defect area, and nerves per total surface. PubMed and EMBASE were screened for studies published until July 2014. Cross-referencing and hand searching were used to identify further articles. Standardized mean differences (SMD) and 95% confidence intervals (95% CI) were calculated using random-effects meta-analysis. To assess possible bias, SYRCLE's risk of bias tool for animal studies was used. From 1364 screened articles, five studies (representing 64 animals) were included in the quantitative analysis. Risk of bias of all studies was high. Stem/progenitor cell-transplanted pulps showed significantly larger regenerated pulp area per root canal total area (SMD [95% CI]: 2.28 [0.35-4.21]) and regenerated dentin area per root canal total area (SMD: 6.91 [5.39-8.43]) compared with no stem/progenitor cell transplantation controls. Only one study reported on capillaries per or nerves per total surface and found both significantly increased in stem/progenitor cell-transplanted pulps compared with controls. Stem/progenitor cell transplantation seems to enhance pulp-dentin complex regeneration in animal models

  16. Novel laser Doppler flowmeter for pulpal blood flow measurements

    NASA Astrophysics Data System (ADS)

    Zang, De Yu; Millerd, James E.; Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.

    1996-04-01

    We have proposed and experimentally demonstrated a new configuration of laser Doppler flowmetry for dental pulpal blood flow measurements. To date, the vitality of a tooth can be determined only by subjective thermal or electric tests, which are of questionable reliability and may induced pain in patient. Non-invasive techniques for determining pulpal vascular reactions to injury, treatment, and medication are in great demand. The laser Doppler flowmetry technique is non-invasive; however, clinical studies have shown that when used to measure pulpal blood flow the conventional back-scattering Doppler method suffers from low signal-to-noise ratio (SNR) and unreliable flux readings rendering it impossible to calibrate. A simplified theoretical model indicates that by using a forward scattered geometry the detected signal has a much higher SNR and can be calibrated. The forward scattered signal is readily detectable due to the fact that teeth are relatively thin organs with moderate optical loss. A preliminary experiment comparing forward scattered detection with conventional back- scattered detection was carried out using an extracted human molar. The results validated the findings of the simple theoretical model and clearly showed the utility of the forward scattering geometry. The back-scattering method had readings that fluctuated by as much as 187% in response to small changes in sensor position relative to the tooth. The forward scattered method had consistent readings (within 10%) that were independent of the sensor position, a signal-to-noise ratio that was at least 5.6 times higher than the back-scattering method, and a linear response to flow rate.

  17. Atmospheric leakage and condensate production in NASA's biomass production chamber. Effect of diurnal temperature cycles

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Drese, John H.; Sager, John C.

    1991-01-01

    A series of tests were conducted to monitor atmospheric leakage rate and condensate production in NASA's Biomass Production Chamber (BPC). Water was circulated through the 64 plant culture trays inside the chamber during the tests but no plants were present. Environmental conditions were set to a 12-hr photoperiod with either a matching 26 C (light)/20 C (dark) thermoperiod, or a constant 23 C temperature. Leakage, as determined by carbon dioxide decay rates, averaged about 9.8 percent for the 26 C/20 C regime and 7.3 percent for the constant 23 C regime. Increasing the temperature from 20 C to 26 C caused a temporary increase in pressure (up to 0.5 kPa) relative to ambient, while decreasing the temperature caused a temporary decrease in pressure of similar magnitude. Little pressure change was observed during transition between 23 C (light) and 23 C (dark). The lack of large pressure events under isothermal conditions may explain the lower leakage rate observed. When only the plant support inserts were placed in the culture trays, condensate production averaged about 37 liters per day. Placing acrylic germination covers over the tops of culture trays reduced condensate production to about 7 liters per day. During both tests, condensate production from the lower air handling system was 60 to 70 percent greater than from the upper system, suggesting imbalances exist in chilled and hot water flows for the two air handling systems. Results indicate that atmospheric leakage rates are sufficiently low to measure CO2 exchange rates by plants and the accumulation of certain volatile contaminants (e.g., ethylene). Control system changes are recommended in order to balance operational differences (e.g., humidity and temperature) between the two halves of the chamber.

  18. Effects of chamber temperature and pressure on the characteristics of high speed diesel jets

    NASA Astrophysics Data System (ADS)

    Sittiwong, W.; Pianthong, K.; Seehanam, W.; Milton, B. E.; Takayama, K.

    2012-05-01

    This study is an investigation into the effects of temperature and pressure within a test chamber on the dynamic characteristics of injected supersonic diesel fuel jets. These jets were generated by the impact of a projectile driven by a horizontal single stage powder gun. A high speed video camera and a shadowgraph optical system were used to capture their dynamic characteristics. The test chamber had controlled air conditions of temperature and pressure up to 150 °C and 8.2 bar, respectively. It was found experimentally that, at the highest temperature, a maximum jet velocity of around 1,500 m/s was obtained. At this temperature, a narrow pointed jet appeared while at the highest pressure, a thick, blunt headed jet was obtained. Strong shock waves were generated in both cases at the jet head. For analytical prediction, equations of jet tip velocity and penetration from the work of Dent and of Hiroyasu were employed to describe the dynamic characteristics of the experiments at a standard condition of 1 bar, 30 °C. These analytical predictions show reasonable agreement to the experimental results, the experimental trend differing in slope because of the effect of the pressure, density fluctuation of the injection and the shock wave phenomena occurring during the jet generation process.

  19. Ellipsometry with polarisation analysis at cryogenic temperatures inside a vacuum chamber

    SciTech Connect

    Bauer, S.; Grees, B.; Spitzer, D.; Beck, M.; Bottesch, R.; Ortjohann, H.-W.; Schäfer, T.; Wegmann, A.; Zbořil, M.; Weinheimer, C.; Ostrick, B.; Telle, H. H.

    2013-12-15

    In this paper we describe a new variant of null ellipsometry to determine thicknesses and optical properties of thin films on a substrate at cryogenic temperatures. In the PCSA arrangement of ellipsometry the polarizer and the compensator are placed before the substrate and the analyzer after it. Usually, in the null ellipsometry the polarizer and the analyzer are rotated to find the searched minimum in intensity. In our variant we rotate the polarizer and the compensator instead, both being placed in the incoming beam before the substrate. Therefore the polarisation analysis of the reflected beam can be realized by an analyzer at fixed orientation. We developed this method for investigations of thin cryogenic films inside a vacuum chamber where the analyzer and detector had to be placed inside the cold shield at a temperature of T≈ 90 K close to the substrate. All other optical components were installed at the incoming beam line outside the vacuum chamber, including all components which need to be rotated during the measurements. Our null ellipsometry variant has been tested with condensed krypton films on a highly oriented pyrolytic graphite substrate (HOPG) at a temperature of T≈ 25 K. We show that it is possible to determine the indices of refraction of condensed krypton and of the HOPG substrate as well as thickness of krypton films with reasonable accuracy.

  20. Ellipsometry with polarisation analysis at cryogenic temperatures inside a vacuum chamber

    NASA Astrophysics Data System (ADS)

    Bauer, S.; Grees, B.; Spitzer, D.; Beck, M.; Bottesch, R.; Ortjohann, H.-W.; Ostrick, B.; Schäfer, T.; Telle, H. H.; Wegmann, A.; Zbořil, M.; Weinheimer, C.

    2013-12-01

    In this paper we describe a new variant of null ellipsometry to determine thicknesses and optical properties of thin films on a substrate at cryogenic temperatures. In the PCSA arrangement of ellipsometry the polarizer and the compensator are placed before the substrate and the analyzer after it. Usually, in the null ellipsometry the polarizer and the analyzer are rotated to find the searched minimum in intensity. In our variant we rotate the polarizer and the compensator instead, both being placed in the incoming beam before the substrate. Therefore the polarisation analysis of the reflected beam can be realized by an analyzer at fixed orientation. We developed this method for investigations of thin cryogenic films inside a vacuum chamber where the analyzer and detector had to be placed inside the cold shield at a temperature of T ≈ 90 K close to the substrate. All other optical components were installed at the incoming beam line outside the vacuum chamber, including all components which need to be rotated during the measurements. Our null ellipsometry variant has been tested with condensed krypton films on a highly oriented pyrolytic graphite substrate (HOPG) at a temperature of T ≈ 25 K. We show that it is possible to determine the indices of refraction of condensed krypton and of the HOPG substrate as well as thickness of krypton films with reasonable accuracy.

  1. Antioxidant therapy enhances pulpal healing in bleached teeth

    PubMed Central

    Lima, Adriano Fonseca; Marques, Marcelo Rocha; Soares, Diana Gabriela; Hebling, Josimeri; Marchi, Giselle Maria

    2016-01-01

    Objectives The purpose of this study was to evaluate the histopathological effects of an antioxidant therapy on the pulp tissue of rat teeth exposed to a bleaching gel with 35% hydrogen peroxide. Materials and Methods Forty rats were subjected to oral ingestion by gavage of distilled water (DW) or ascorbic acid (AA) 90 min before the bleaching therapy. For the bleaching treatment, the agent was applied twice for 5 min each to buccal surfaces of the first right mandibular molars. Then, the animals were sacrificed at 6 hr, 24 hr, 3 day, or 7 day post-bleaching, and the teeth were processed for microscopic evaluation of the pulp tissue. Results At 6 hr, the pulp tissue showed moderate inflammatory reactions in all teeth of both groups. In the DW and AA groups, 100% and 80% of teeth exhibited pulp tissue with significant necrosis and intense tissue disorganization, respectively. At 24 hr, the AA-treated group demonstrated a greater regenerative capability than the DW group, with less intense inflammatory reaction and new odontoblast layer formation in 60% of the teeth. For up to the 7 day period, the areas of pulpal necrosis were replaced by viable connective tissue, and the dentin was underlined by differentiated odontoblast-like cells in most teeth of both groups. Conclusions A slight reduction in initial pulpal damage during post-bleaching was promoted by AA therapy. However, the pulp tissue of AA-treated animals featured faster regenerative potential over time. PMID:26877990

  2. Pulpal disease and bursts of periodontal attachment loss.

    PubMed

    Hirsch, R S; Clarke, N G

    1993-11-01

    Progression of periodontitis is currently thought to occur during bursts of activity, followed by periods of remission, when healing may occur. This concept contrasts with the older hypothesis that periodontitis was continuously, but slowly, progressive throughout life. At present, there is no proof of the conventional (microbiological) hypothesis which gives a major role to site-specific bacteria in the initiation of bursts of attachment loss. An alternative hypothesis is presented in this paper which accounts for periodontal attachment loss by pathways that are independent of plaque. Severe lesions of the periodontium caused by pulpal pathoses (apical and retrograde periodontitis) are known to form at any level of the periodontium, not only at the root apex. When these lesions cause destruction of the periodontal tissues at the alveolar crest, and when plaque, calculus and gingivitis are also present, an endodontic origin is rarely suspected. Three pathways are proposed to account for the development of localized periodontal attachment loss consequent to pulpal disease. This hypothesis accounts for the sudden deterioration of periodontal sites under regular review, the strict localization of alveolar defects with normal alveolar bone immediately adjacent, the presence of site-specific bacteria (secondary colonizers of deep pockets) which cannot cause disease when transferred to healthy sites, and the antibody responses directed against them. PMID:8144246

  3. Demonstrated survivability of a high temperature optical fiber cable on a 1500 pound thrust rocket chamber

    NASA Technical Reports Server (NTRS)

    Sovie, Amy L.

    1992-01-01

    A demonstration of the ability of an existing optical fiber cable to survive the harsh environment of a rocket engine was performed at the NASA Lewis Research Center. The intent of this demonstration was to prove the feasibility of applying fiber optic technology to rocket engine instrumentation systems. Extreme thermal transient tests were achieved by wrapping a high temperature optical fiber, which was cablized for mechanical robustness, around the combustion chamber outside wall of a 1500 lb Hydrogen-Oxygen rocket engine. Additionally, the fiber was wrapped around coolant inlet pipes which were subject to near liquid hydrogen temperatures. Light from an LED was sent through the multimode fiber, and output power was monitored as a function of time while the engine was fired. The fiber showed no mechanical damage after 419 firings during which it was subject to transients from 30 K to 350 K, and total exposure time to near liquid hydrogen temperatures in excess of 990 seconds. These extreme temperatures did cause attenuation greater than 3 dB, but the signal was fully recovered at room temperature. This experiment demonstrates that commercially available optical fiber cables can survive the environment seen by a typical rocket engine instrumentation system, and disclose a temperature-dependent attenuation observed during exposure to near liquid hydrogen temperatures.

  4. An Insight Into Neurophysiology of Pulpal Pain: Facts and Hypotheses

    PubMed Central

    Gupta, Abhishek; N., Meena

    2013-01-01

    Pain and pain control are important to the dental profession because the general perception of the public is that dental treatment and pain go hand in hand. Successful dental treatment requires that the source of pain be detected. If the origin of pain is not found, inappropriate dental care and, ultimately, extraction may result. Pain experienced before, during, or after endodontic therapy is a serious concern to both patients and endodontists, and the variability of discomfort presents a challenge in terms of diagnostic methods, endodontic therapy, and endodontic knowledge. This review will help clinicians understand the basic neurophysiology of pulpal pain and other painful conditions of the dental pulp that are not well understood. PMID:24156000

  5. High Temperature Fission Chamber for He- and FLiBe-cooled Reactors

    SciTech Connect

    Bell, Zane W.; Giuliano, Dominic R.; Holcomb, David Eugene; Lance, Michael J.; Miller, Roger G.; Warmack, Robert J. Bruce; Wilson, Dane F.; Harrison, Mark J.

    2015-01-01

    We have evaluated candidate technologies for in-core fission chambers for high-temperature reactors to monitor power level via measurements of neutron flux from start-up through full power at up to 800°C. This research is important because there are no commercially available instruments capable of operating above 550 °C. Component materials and processes were investigated for fission chambers suitable for operation at 800 °C in reactors cooled by molten fluoride salt (FLiBe) or flowing He, with an emphasis placed on sensitivity (≥ 1 cps/nv), service lifetime (2 years at full power), and resistance to direct immersion in FLiBe. The latter gives the instrument the ability to survive accidents involving breach of a thimble. The device is envisioned to be a two-gap, three-electrode instrument constructed from concentric nickel-plated alumina cylinders and using a noble gas–nitrogen fill-gas. We report the results of measurements and calculations of the response of fill gasses, impurity migration in nickel alloy, brazing of the alumina insulator, and thermodynamic calculations.

  6. Analysis of a water-coolant leak into a very high-temperature vitrification chamber.

    SciTech Connect

    Felicione, F. S.

    1998-06-11

    A coolant-leakage incident occurred during non-radioactive operation of the Plasma Hearth Process waste-vitrification development system at Argonne National Laboratory when a stray electric arc ruptured az water-cooling jacket. Rapid evaporation of the coolant that entered the very high-temperature chamber pressurized the normally sub-atmospheric system above ambient pressure for over 13 minutes. Any positive pressurization, and particularly a lengthy one, is a safety concern since this can cause leakage of contaminants from the system. A model of the thermal phenomena that describe coolant/hot-material interactions was developed to better understand the characteristics of this type of incident. The model is described and results for a variety of hypothetical coolant-leak incidents are presented. It is shown that coolant leak rates above a certain threshold will cause coolant to accumulate in the chamber, and evaporation from this pool can maintain positive pressure in the system long after the leak has been stopped. Application of the model resulted in reasonably good agreement with the duration of the pressure measured during the incident. A closed-form analytic solution is shown to be applicable to the initial leak period in which the peak pressures are generated, and is presented and discussed.

  7. Periodontal repair of periapical lesions: the borderland between pulpal and periodontal disease.

    PubMed

    Gold, S I; Moskow, B S

    1987-05-01

    A series of cases demonstrating the destruction of periapical periodontal structures, without pulpal involvement has been presented. Treatment using both surgery and antibiotics resulted in extensive healing without any concommitant endodontic therapy. The results suggest that lesions affecting the apical periodontium are either periodontal or pulpal in origin. Careful diagnosis allows the maintenance of pulp vitality in cases where apical destruction has a source other than an infected pulp. The commonly held belief that lateral and accessory canals are a significant source of pulpal contamination from deep periodontal pockets has been questioned. PMID:3475293

  8. Effects of carbon dioxide and temperature on crops: Lessons from SPAR growth chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sunlit growth chambers, known as Soil-Plant-Atmosphere-Research (SPAR) chambers, provide a unique environment for studying and quantifying the effects of environmental variables, either alone or in combination, on plant growth and development. SPAR chambers are appropriate for short-term or entire g...

  9. Budget-limited thermal biology: Design, construction and performance of a large, walk-in style temperature-controlled chamber.

    PubMed

    Martinez, Eloy; Agosta, Salvatore J

    2016-05-01

    We describe a partial redesign of the conventional air-conditioning system and apply it to the construction of a relatively large (1.87m(3) air mass), walk-in style temperature-controlled chamber (TCC) using parts easily obtained in most countries. We conducted several tests to demonstrate the performance of the TCC. Across the physiologically relevant range of 5-37°C, the TCC took 26.5-50.0min to reach the desired set point temperature. Once at set point, temperature inside the chamber was controlled with an accuracy of ±1.0°C. User-entry effects on deviations from and return times to set point temperature were minimal. Overall, performance of the TCC was sufficient to make precise physiological measurements of insect metabolic rate while controlling assay temperature. Major advantages of the TCC include its simplicity, flexibility, and low cost. PMID:27157331

  10. An experimental and computational investigation of the standard temperature-pressure correction factor for ion chambers in kilovoltage x rays

    SciTech Connect

    La Russa, Daniel J.; McEwen, Malcolm; Rogers, D. W. O.

    2007-12-15

    For ion chambers with cavities open to the surrounding atmosphere, the response measured at a given temperature and pressure must be corrected using the standard temperature-pressure correction factor (P{sub TP}). A previous paper based solely on Monte Carlo simulations [D. J. La Russa and D. W. O. Rogers, Med. Phys. 33, 4590-4599 (2006)] pointed out the shortcomings of the P{sub TP} correction factor when used to correct the response of non-air-equivalent chambers for low-energy x-ray beams. This work presents the results of several experiments that corroborate these calculations for a number of ion chambers. Monte Carlo simulations of the experimental setup revealed additional insight into the various factors affecting the extent of the breakdown of P{sub TP}, including the effect of impurities and the sensitivity to chamber dimensions. For an unfiltered 60 kV beam, the P{sub TP}-corrected response of an NE 2571 ion chamber measured at 0.7 atm was 2.5% below the response measured at reference conditions. In general, Monte Carlo simulations of the experimental setup using EGSnrc were within 0.5% of measured values. EGSnrc-calculated values of air kerma calibration coefficients (N{sub K}) at low x-ray energies are also provided as a means of estimating the level of impurities in the chambers investigated. Calculated values of N{sub K} normalized to the value measured for a 250 kV beam were obtained for three chambers and were within 1% of experiment with one exception, the Exradin A12 in a 50 kV beam.

  11. Effects of CO2 and temperature on crops: Lessons from growth chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sunlit growth chambers known as Soil-Plant-Atmosphere-Research (SPAR) provide a unique environment for studying and quantifying the effects of environmental variables either alone or in combination on plant growth and development. SPAR chambers are appropriate for short-term or entire growing season...

  12. Measurement of electron temperature and density in the DIII-D neutral beam ion source arc chamber

    SciTech Connect

    Kellman, D.H.; Busath, J.; Hong, R.

    1993-10-01

    A swept-bias Langmuir probe diagnostic was employed with the DIII-D neutral beam ion source in an effort to study the effects of filament temperature, arc power, and backstreaming energetic electrons on the electron temperature and density of the arc discharge inside the ion source arc chamber. The arc chamber contains six Langmuir probes biased with a negative dc voltage. These probes provide a feedback signal for regulation of the arc power supply, and give a relative indication of plasma uniformity within the arc chamber. For this study, one probe was reconnected to a voltage-sweeping power supply, and probe current versus voltage characteristics were generated. These characteristics provided the information necessary to calculate electron temperature and density. With arc discharge only, the results demonstrated that an filament temperature increases, so does electron density. Electron temperature decreases at a faster rate, however, as required to maintain constant ion maturation current (regulated by the arc power supply). The results also demonstrated that increasing arc power (through control of the arc power supply) results in higher electron temperature and density. Experiments were also performed with probe voltage sweeps during beam extraction, at various accelerator voltage levels and at different delay times after beam turn-on with a fixed acceleration voltage. These results indicated an increase in electron temperature and density as acceleration voltage is increased. However, nearly identical trends result when arc discharges are produced at the same parameter settings as during these beams, but without beam extraction. This indicates minimal influence of backstreaming energetic electrons on electron temperature and density in the arc chamber. Temperature and density also remain fairly constant over time during a long beam pulse.

  13. The Evaluation of High Temperature Adhesive Bonding Processes for Rocket Engine Combustion Chamber Applications

    NASA Technical Reports Server (NTRS)

    McCray, Daniel; Smith, Jeffrey; Rice, Brian; Blohowiak, Kay; Anderson, Robert; Shin, E. Eugene; McCorkle, Linda; Sutter, James

    2003-01-01

    NASA Glenn Research Center is currently evaluating the possibility of using high- temperature polymer matrix composites to reinforce the combustion chamber of a rocket engine. One potential design utilizes a honeycomb structure composed of a PMR-II- 50/M40J 4HS composite facesheet and titanium honeycomb core to reinforce a stainless steel shell. In order to properly fabricate this structure, adhesive bond PMR-II-50 composite. Proper prebond surface preparation is critical in order to obtain an acceptable adhesive bond. Improperly treated surfaces will exhibit decreased bond strength and durability, especially in metallic bonds where interface are susceptible to degradation due to heat and moisture. Most treatments for titanium and stainless steel alloys require the use of strong chemicals to etch and clean the surface. This processes are difficult to perform due to limited processing facilities as well as safety and environmental risks and they do not consistently yield optimum bond durability. Boeing Phantom Works previously developed sol-gel surface preparations for titanium alloys using a PETI-5 based polyimide adhesive. In support of part of NASA Glenn Research Center, UDRI and Boeing Phantom Works evaluated variations of this high temperature sol-gel surface preparation, primer type, and primer cure conditions on the adhesion performance of titanium and stainless steel using Cytec FM 680-1 polyimide adhesive. It was also found that a modified cure cycle of the FM 680-1 adhesive, i.e., 4 hrs at 370 F in vacuum + post cure, significantly increased the adhesion strength compared to the manufacturer's suggested cure cycle. In addition, the surface preparation of the PMR-II-50 composite was evaluated in terms of surface cleanness and roughness. This presentation will discuss the results of strength and durability testing conducted on titanium, stainless steel, and PMR-II-50 composite adherends to evaluate possible bonding processes.

  14. Substrate temperature and strain during sputter deposition of aluminum on cast borosilicate glass in a Gemini Observatory coating chamber.

    PubMed

    Sebag, Jacques; Andrew, John; Neill, Douglas; Warner, Michael

    2010-08-20

    Temperature and strain measurements obtained during coating of spin-cast borosilicate samples are presented here with an analysis of these results. These tests were performed for the Large Synoptic Survey Telescope (LSST) project to verify the possible use of sputtering deposition of optical coating on its large 8.4m diameter primary-tertiary mirror. Made of spin-cast borosilicate glass, the working stress of the mirror's nonpolished surfaces is 100 psi (0.69 MPa), resulting in a local temperature difference limit of 5 degrees C. To ensure representative environmental conditions, the tests were performed in the Gemini Observatory coating chamber located in Hawaii, whose design was utilized to develop the LSST coating chamber design. In particular, this coating chamber is equipped with linear magnetrons built with cooled heat shields directly facing the mirror surface. These measurements have demonstrated that it will be safe for the LSST to use a magnetron sputtering process for coating its borosilicate primary-tertiary mirror. PMID:20733633

  15. Study of radiation heat transfer and the temperature state in the combustion chambers of small-size gas-turbine engines (GTEs)

    NASA Astrophysics Data System (ADS)

    Lukash, V. P.

    1993-03-01

    The experimental data on the radiation flux surface density distribution in the combusion chamber of a small-size gas-turbine engine are presented. Experiments are made at elevated pressures and temperatures of the stagnated flow at the chamber inlet. Satisfactory agreement between theory and experiment is obtained.

  16. Endogenous vasoactive substances and oxygen-derived free radicals in pulpal haemodynamics.

    PubMed

    Okabe, E

    1994-01-01

    An adequate blood supply to the dental pulp is essential to the health of the tooth. A recent concept is that repeated stimulation of sensitive teeth may induce pulpal changes; this could occur through induction of neurogenic inflammation and alteration of pulpal blood flow. One possibility is that production of oxygen-derived free radicals at sites of inflammation contributes to alterations in local blood flow. The first target of free radicals, generated in several pathological processes, is the vascular system (essentially the endothelium). Although the exact mechanism by which free radicals induce changes in vascular conductance is still uncertain, they may act directly on vascular smooth muscle or modify vascular tone by interacting with the production and/or biological activity of endogenous vasoactive mediators. Recent data indicate that the oxygen-derived, free radical-generating system can decrease pulpal blood flow in the dog via endothelial dysfunction when applied locally in deep dentinal cavities. In addition to the part played by oxygen-derived free radicals, the measurement of pulpal blood flow and the effects of endogenous vasoactive substances on flow are discussed. PMID:7702466

  17. Differentiation capacity of BrdU label-retaining dental pulp cells during pulpal healing following allogenic transplantation in mice.

    PubMed

    Saito, Kotaro; Ishikawa, Yuko; Nakakura-Ohshima, Kuniko; Ida-Yonemochi, Hiroko; Nakatomi, Mitsushiro; Kenmotsu, Shin-Ichi; Ohshima, Hayato

    2011-08-01

    Our recent study has demonstrated the localization of putative dental pulp stem cells in the developing molar by chasing 5-bromo-2'-deoxyuridine (BrdU)-labeling. However, their differentiation capacity subsequent to the tooth transplantation remains to be elucidated. This study aims to clarify the differentiation capacity of BrdU label-retaining dental pulp cells and their relationship to cell proliferation and apoptosis during pulpal healing following allogenic transplantation in mice. Following extraction of the mouse molar in BrdU-labeled animals, the roots and pulp floor were resected and immediately allo-grafted into the sublingual region in non-labeled animals, and vice versa. In the labeled transplants, label-retaining cells (LRCs) were increased in number and committed in nestin-positive newly differentiated odontoblast-like cells, whereas they were not committed in osteoblast-like cells. In the labeled host, on the contrary, LRCs were committed in neither odontoblast- nor osteoblast-like cells, although they were transiently increased in number and finally disappeared in the pulp tissue of the transplants. Interestingly, numerous apoptotic cells appeared in the pulp tissue including LRCs during the experimental period. These results suggest that transplanted LRCs maintain their proliferative and differentiation capacity in spite of extensive apoptosis occurring in the transplant, whereas transiently increased host-derived LRCs finally disappear in the pulp chamber following apoptosis. PMID:21878732

  18. Management of pulpal floor perforation and grade II Furcation involvement using mineral trioxide aggregate and platelet rich fibrin: A clinical report

    PubMed Central

    Bains, Rhythm; Bains, Vivek K.; Loomba, Kapil; Verma, Kavita; Nasir, Afreena

    2012-01-01

    To report the management of an iatrogenic perforation of pulpal floor in the furcation of mandibular first molar, using Mineral Trioxide Aggregate (MTA) and platelet rich fibrin (PRF). Unpredictable endodontic root/pulp chamber floor perforations resulting in unacceptable high rate of clinical failure has now been a lesser threat with the advent of new technologies and biocompatible materials that utilize the applications of basic research along with tissue engineering concept in clinical practice. Present case report illustrates the use of MTA and platelet rich fibrin (PRF) for the repair of the perforation defect and regeneration of the lost periodontium in furcation area. Although, histologic events and reaction of MTA with PRF is not studied so far, however, the autologous and biocompatible nature of the components used for present treatment modalities seems to be beneficial for the long term clinical results obtained in our case. PMID:23230369

  19. Temperature-Programmed Natural Convection for Micromixing and Biochemical Reaction in a Single Microfluidic Chamber

    PubMed Central

    Kim, Sung-Jin; Wang, Fang; Burns, Mark A.; Kurabayashi, Katsuo

    2009-01-01

    Micromixing is a crucial step for biochemical reactions in microfluidic networks. A critical challenge is that the system containing micromixers needs numerous pumps, chambers, and channels not only for the micromixing but also for the biochemical reactions and detections. Thus, a simple and compatible design of the micromixer element for the system is essential. Here, we propose a simple, yet effective, scheme that enables micromixing and a biochemical reaction in a single microfluidic chamber without using any pumps. We accomplish this process by using natural convection in conjunction with alternating heating of two heaters for efficient micromixing, and by regulating capillarity for sample transport. As a model application, we demonstrate micromixing and subsequent polymerase chain reaction (PCR) for an influenza viral DNA fragment. This process is achieved in a platform of a microfluidic cartridge and a microfabricated heating-instrument with a fast thermal response. Our results will significantly simplify micromixing and a subsequent biochemical reaction that involves reagent heating in microfluidic networks. PMID:19419189

  20. Flow chamber

    DOEpatents

    Morozov, Victor

    2011-01-18

    A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.

  1. A pressurized ion chamber monitoring system for environmental radiation measurements utilizing a wide-range temperature-compensated electrometer

    SciTech Connect

    Stevenick, W. Van . Environmental Measurements Lab.)

    1994-08-01

    The performance of a complete pressurized ion chamber (PIC) radiation monitoring system is described. The design incorporates an improved temperature-compensated electrometer which is stable to [+-]3 [center dot] 10[sup [minus]16] A over the environmental range of temperature ([minus]40 to +40 C). Using a single 10[sup 11] [Omega] feed-back resistor, the electrometer accurately measures currents over a range from 3 [center dot] 10[sup [minus]15] A to 3 [center dot] 10[sup [minus]11] A. While retaining the sensitivity of the original PIC system (the instrument responds readily to small background fluctuations on the order of 0.1 [mu]R h[sup [minus]1]), the new system measures radiation levels up to the point where the collection efficiency of the ion chamber begins to drop off, typically [approximately]27 pA at 1 mR h[sup [minus]1]. A data recorder and system controller was designed using the Tattletale[trademark] Model 4A computer. Digital data is stored on removable solid-state, credit-card style memory cards.

  2. Two chamber reaction furnace

    DOEpatents

    Blaugher, R.D.

    1998-05-05

    A vertical two chamber reaction furnace is described. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 C and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

  3. Two chamber reaction furnace

    DOEpatents

    Blaugher, Richard D.

    1998-05-05

    A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

  4. An in vivo evaluation of the change in the pulpal oxygen saturation after administration of preoperative anxiolytics and local anesthesia

    PubMed Central

    P. Shetty, Krishna; V. Satish, Sarvepalli; Kilaru, Krishnarao; Chakravarthi Ponangi, Kalyana; M. Luke, Alexander; Neshangi, Srisha

    2016-01-01

    Background. Given the influence of systemic blood pressure on pulpal blood flow, anxiolytics prescribed may alter the pulpal blood flow along with the local anesthetic solution containing a vasoconstrictor. This study evaluated the impact of preoperative anxiolytics and vasoconstrictors in local anesthetic agents on pulpal oxygen saturation. Methods. Thirty anxious young healthy individuals with a mean age of 24 years were randomly selected using the Corah’s Dental Anxiety Scale (DAS). After checking the vital signs the initial pulpal oxygen saturation (initial SpO2) was measured using a pulse oximeter. Oral midzolam was administered at a dose of 7.5 mg. After 30 min, the vital signs were monitored and the pulpal oxygen saturation (anxiolytic SpO2) was measured. A total of 1.5 mL of 2% lidocaine with 1:200000 epinephrine was administered as buccal infiltration anesthesia and 10 min the final pulpal oxygen saturation (L.A SpO2) was measured. Results. The mean initial (SpO2) was 96.37% which significantly decreased to 90.76% (SpO2) after the administration of the anxiolytic agent. This drop was later accentuated to 85.17% (SpO2) after administration of local anesthetic solution. Statistical significance was set at P<0.0001. Conclusion. High concentrations of irritants may permeate dentin due to a considerable decrease in the pulpal blood flow from crown or cavity preparation. Therefore, maintaining optimal blood flow during restorative procedures may prevent pulpal injury. PMID:27092212

  5. An in vivo evaluation of the change in the pulpal oxygen saturation after administration of preoperative anxiolytics and local anesthesia.

    PubMed

    P Shetty, Krishna; V Satish, Sarvepalli; Kilaru, Krishnarao; Chakravarthi Ponangi, Kalyana; M Luke, Alexander; Neshangi, Srisha

    2016-01-01

    Background. Given the influence of systemic blood pressure on pulpal blood flow, anxiolytics prescribed may alter the pulpal blood flow along with the local anesthetic solution containing a vasoconstrictor. This study evaluated the impact of preoperative anxiolytics and vasoconstrictors in local anesthetic agents on pulpal oxygen saturation. Methods. Thirty anxious young healthy individuals with a mean age of 24 years were randomly selected using the Corah's Dental Anxiety Scale (DAS). After checking the vital signs the initial pulpal oxygen saturation (initial SpO2) was measured using a pulse oximeter. Oral midzolam was administered at a dose of 7.5 mg. After 30 min, the vital signs were monitored and the pulpal oxygen saturation (anxiolytic SpO2) was measured. A total of 1.5 mL of 2% lidocaine with 1:200000 epinephrine was administered as buccal infiltration anesthesia and 10 min the final pulpal oxygen saturation (L.A SpO2) was measured. Results. The mean initial (SpO2) was 96.37% which significantly decreased to 90.76% (SpO2) after the administration of the anxiolytic agent. This drop was later accentuated to 85.17% (SpO2) after administration of local anesthetic solution. Statistical significance was set at P<0.0001. Conclusion. High concentrations of irritants may permeate dentin due to a considerable decrease in the pulpal blood flow from crown or cavity preparation. Therefore, maintaining optimal blood flow during restorative procedures may prevent pulpal injury. PMID:27092212

  6. MEASUREMENT OF VOCS DESORBED FROM BUILDING MATERIALS--A HIGH TEMPERATURE DYNAMIC CHAMBER METHOD

    EPA Science Inventory

    Mass balance is a commonly used approach for characterizing the source and sink behavior of building materials. Because the traditional sink test methods evaluate the adsorption and desorption of volatile organic compounds (VOC) at ambient temperatures, the desorption process is...

  7. Controlled simulation of optical turbulence in a temperature gradient air chamber

    NASA Astrophysics Data System (ADS)

    Toselli, Italo; Wang, Fei; Korotkova, Olga

    2016-05-01

    Atmospheric turbulence simulator is built and characterized for in-lab optical wave propagation with controlled strength of the refractive-index fluctuations. The temperature gradients are generated by a sequence of heat guns with controlled individual strengths. The temperature structure functions are measured in two directions transverse to propagation path with the help of a thermocouple array and used for evaluation of the corresponding refractive-index structure functions of optical turbulence.

  8. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber

    SciTech Connect

    Manova, D.; Bergmann, A.; Maendl, S.; Neumann, H.; Rauschenbach, B.

    2012-11-15

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton{sup Registered-Sign} windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

  9. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber

    NASA Astrophysics Data System (ADS)

    Manova, D.; Bergmann, A.; Mändl, S.; Neumann, H.; Rauschenbach, B.

    2012-11-01

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton® windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

  10. Maintenance of pulpal vitality in a tooth with deep caries: a case report.

    PubMed

    Massara, Maria Lourdes de Andrade; Tavares, Warley Luciano Fonseca; Sobrinho, Antônio Paulino Ribeiro

    2016-01-01

    Deep caries can induce severe inflammatory reactions. However, inflamed pulp can heal if the demineralization process is interrupted and inactivated sufficiently early. The aim of this case report is to describe the use of stepwise excavation to treat a mature permanent tooth that exhibited deep caries and apical periodontitis. A 12-year-old girl was experiencing lingering pain lasting for a few minutes in the mandibular left second molar when drinking cold water. Clinical and radiographic examinations suggested that a conservative therapeutic approach could be successful. The tooth was anesthetized and isolated, and the unsupported enamel was removed. The remaining affected dentin was left on the pulpal floor, which was protected by a thin layer of calcium hydroxide cement. The tooth was sealed with temporary cement. Three months later, pulpal sensitivity was reduced. The pulp was found to be healthy at a 9-month follow-up examination. The cavity was definitively restored with glass ionomer cement and composite resin applied with the sandwich technique. At the 4-year follow-up, the tooth remained functional, presenting standard color and satisfactory restoration. The periodontal tissues were healthy, and radiographic images indicated that the width of the periodontal ligament space was normal. This case demonstrates that clinical diagnosis should prevail over radiographic findings, even in cases where a radiographic widening of the periodontal ligament space suggests irreversible pulpal damage. PMID:27367630

  11. Application of fuzzy logic to the control of wind tunnel settling chamber temperature

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Humphreys, Gregory L.

    1994-01-01

    The application of Fuzzy Logic Controllers (FLC's) to the control of nonlinear processes, typically controlled by a human operator, is a topic of much study. Recent application of a microprocessor-based FLC to the control of temperature processes in several wind tunnels has proven to be very successful. The control of temperature processes in the wind tunnels requires the ability to monitor temperature feedback from several points and to accommodate varying operating conditions in the wind tunnels. The FLC has an intuitive and easily configurable structure which incorporates the flexibility required to have such an ability. The design and implementation of the FLC is presented along with process data from the wind tunnels under automatic control.

  12. Bakeout Chamber Within Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    Taylor, Daniel M.; Soules, David M.; Barengoltz, Jack B.

    1995-01-01

    Vacuum-bakeout apparatus for decontaminating and measuring outgassing from pieces of equipment constructed by mounting bakeout chamber within conventional vacuum chamber. Upgrade cost effective: fabrication and installation of bakeout chamber simple, installation performed quickly and without major changes in older vacuum chamber, and provides quantitative data on outgassing from pieces of equipment placed in bakeout chamber.

  13. DESIGN, FABRICATION, ASSEMBLY AND BENCH TESTING OF A TEXACO INFRARED RATIO PYROMETER SYSTEM FOR THE MEASUREMENT OF REACTION CHAMBER TEMPERATURE

    SciTech Connect

    Tom Leininger

    2001-03-31

    Reliable measurement of gasifier reaction chamber temperature is important for the proper operation of slagging, entrained-flow gasification processes. Historically, thermocouples have been used as the main measurement technique, with the temperature inferred from syngas methane concentration being used as a backup measurement. While these have been sufficient for plant operation in many cases, both techniques suffer from limitations. The response time of methane measurements is too slow to detect rapid upset conditions, and thermocouples are subject to long-term drift, as well as slag attack, which eventually leads to failure of the thermocouple. Texaco's Montebello Technology Center (MTC) has developed an infrared ratio pyrometer system for measuring gasifier reaction chamber temperature. This system has a faster response time than both methane and thermocouples, and has been demonstrated to provide reliable temperature measurements for longer periods of time when compared to thermocouples installed in the same MTC gasifier. In addition, the system can be applied to commercial gasifiers without any significant scale-up issues. The major equipment items, the purge system, and the safety shutdown system in a commercial plant are essentially identical to the prototypes at MTC. The desired result of this DOE program is ''a bench-scale prototype, either assembled or with critical components (laboratory) tested in a convincing manner.'' The prototype of the pyrometer system (including gasifier optical access port) that was designed, assembled and tested for this program, has had previous prototypes that have been built and successfully tested under actual coal and coke gasification conditions in three pilot units at MTC. It was the intent of the work performed under the auspices of this program to review and update the existing design, and to fabricate and bench test an updated system that can be field tested in one or more commercial gasifiers during a follow on phase

  14. [The reaction of the pulpal blood circulation to thermal stimuli].

    PubMed

    Gängler, P

    1976-01-01

    The present paper characterizes the reactions of the systemcirculation and microcirculation of the pulpa to the effects of temperature changes from--30 degrees C to +55 degrees C. In the range between 25 degrees C and 50 degrees C an increase of the blood flow rate can be observed. By long-standing action of temperatures above 40 degrees C and below 25 degrees C a dilatation of the blood vessels and a decrease of the blood flow rate are caused, thus leading to aggregations, capillary stoppage, and finally to thrombosis of entire pulpa sections. In addition to the outline of the critical initial alterations of the microcirculation in the course of inflammation the clinical conclusions towards crown and cavity preparation by means of water spray cooling, concerning thermal sensibility tests, and cryo-surgical operations are discussed. PMID:135441

  15. Development of a high-resolution room-temperature compressed-xenon cylindrical ionization-chamber gamma radiation detector

    NASA Astrophysics Data System (ADS)

    Tepper, Gary C.; Losee, Jon R.; Palmer, Robert L.

    1998-07-01

    Highly compressed and purified xenon is emerging as an important detection medium for high resolution, room temperature gamma radiation spectroscopy. Detectors based on compressed xenon offer a unique combination of thermal stability, high energy resolution and large volume. Furthermore, fluid based detectors are not susceptible to radiation damage, and can be constructed in a variety of geometries. However, some important factors have delayed the development of practical xenon detectors for widespread use. These factors include the relatively high operational pressures and voltages and the need to maintain extremely high xenon purity. We have recently developed a 0.7 liter gridded ionization chamber xenon gamma radiation detector in a cylindrical geometry. The detector operates at room temperature and provides an intrinsic energy resolution of 1.8% at 662 keV which is five times greater than scintillation based spectrometers. The detector design and performance variables are discussed in comparison to a previous detector constructed in a planar geometry. Our results indicate that practical xenon detectors can now be developed for a wide variety of applications.

  16. Holmium:YAG laser: effect on pulpal tissues and root surfaces

    NASA Astrophysics Data System (ADS)

    Holt, Raleigh A.; Nordquist, Robert E.

    1996-04-01

    The effects of the Holmium:YAG irradiation on the pulpal tissues and surface topography on root surface dentin in human teeth in vivo were studied. The exposed root surfaces of seventeen pre-immediate denture patients were scaled and root planed with a Gracey 3 - 4 curette apical to the dentinoenamel junction until smooth and hard. The prepared root surfaces of two teeth per patient were exposed with Holmium:YAG laser energy after an application of nonfilled resin/fluoride mixture. The laser exposed areas were below the dentinoenamel junction around one-half of each root surface. The opposing sides of each of the teeth received resin/fluoride but no laser energy. A third tooth was identified as a nontreated control. The HO:YAG at 2.12 microns wavelength with a defocused beam size of 3 mm was used. The amount of laser energy delivered per 3 X 5 mm area was 0.450 (+/- .05) joules with a fluence of 2.66 - 3.30 J/cm2. The teeth were extracted after periods of 45 - 120 days. The specimens were fixed in formalin and prepared for histological examination using hematoxylin and eosin stains. Microscopic evaluation of room surfaces showed increased smoothness on the laser treated sites compared to their opposing non-lased sides. Histological examination of the pulpal tissues exhibited no abnormal changes. No clinical symptoms of pulpal pathology were produced. HO:YAG laser energy proved safe for treating room surfaces of human teeth in vivo under conditions presented in this study.

  17. Observations on pulpal response to carbon dioxide laser drilling of dentine in healthy human third molars.

    PubMed

    Nair, P N R; Baltensperger, M; Luder, H U; Eyrich, G K H

    2005-01-01

    Preservation of pulpal health is the primary prerequisite for successful application of laser systems in the hard tissue management of vital teeth. The purpose of this study was to investigate the short and long-term pulpal effects to cavity preparations in healthy human teeth using carbon dioxide (CO2) laser. A total of seven, healthy, third molars that were scheduled to be removed due to space problems were used. After the laser drilling, the occlusal cavities were closed temporarily, and the teeth were extracted 7 days (n=5) and 3 months (n=2) after the operation. The specimens were fixed, decalcified, subdivided and processed for light and transmission electron microscopy. Seven days postoperatively all the five teeth that had been irradiated with the CO2 laser did not reveal any pathological changes in the pulpo-dentine complex. Three months postoperatively the two teeth that were prepared with the laser showed subtle but distinct apposition of tertiary dentine that was lined with intact odontoblasts. One of the specimens at 3 months revealed the presence of a mild, but very circumscribed, pulpal infiltration of chronic inflammatory cells subjacent to the cavity preparation. The latter is unlikely to be due to a direct effect of the laser irradiation but a possible consequence of microleakage of oral antigens and/or other tissue-irritating molecules through the temporary restoration and the remaining dentine thickness (RDT). Although these preliminary histological results suggest that the CO2 laser under investigation induced only minimal response of the dentine-pulp complex when used as a hard-tissue drilling tool, with specific energy settings, pulse duration within thermal relaxation time and emitting radiations at 9.6 microm of wavelength, larger clinical trials involving various types of teeth are necessary to reach definite conclusions for large-scale clinical application of the laser device. PMID:15647971

  18. Development of a nano-tesla magnetic field shielded chamber and highly precise AC-susceptibility measurement coil at μK temperatures

    NASA Astrophysics Data System (ADS)

    Kumar, Anil; Prakash, Om; Ramakrishanan, S.

    2014-04-01

    A special sample measurement chamber has been developed to perform experiments at ultralow temperatures and ultralow magnetic field. A high permeability material known as cryoperm 10 and Pb is used to shield the measurement space consisting of the signal detecting set-up and the sample. The detecting setup consists of a very sensitive susceptibility coil wound on OFHC Cu bobbin.

  19. Single-chamber plasma enhanced chemical vapor deposition of transparent organic/inorganic multilayer barrier coating at low temperature

    SciTech Connect

    Park, S. M.; Kim, D. J.; Kim, S. I.; Lee, N.-E.

    2008-07-15

    Deposition of organic/inorganic multilayers is usually carried out by two different process steps by two different deposition methods. A single-chamber process for the deposition of multilayer stacks can make the process and deposition system simpler. In this work, SiOCH and plasma-polymerized methylcyclohexane (pp-MCH) films and their multilayer stacks for application to transparent diffusion barrier coatings were deposited in a single low-temperature plasma enhanced chemical vapor deposition reactor using hexamethyldisilazane/N{sub 2}O/O{sub 2}/Ar and methylcyclohexane/Ar mixtures for SiOCH and pp-MCH layers, respectively. The deposition rates of the SiOCH and pp-MCH layers were increased with increasing the N{sub 2}O:O{sub 2} gas flow ratio and rf plasma power, respectively. Oxygen concentration in the SiOCH films was decreased and carbon and hydrogen incorporation was increased when increasing the N{sub 2}O:O{sub 2} gas flow ratio from 0:1 to 3:1. In this work, the water vapor transmission rate of polyester sulfone substrate could be reduced from a level of 50 (bare substrate) to 0.8 g/m{sup 2} day after deposition of a pp-MCH/SiOCH/pp-MCH multilayer coating.

  20. Static diffusion cloud chambers

    NASA Technical Reports Server (NTRS)

    Ayers, G.

    1981-01-01

    The chamber geometry and optical arrangement are described. The supersaturation range is given and consists of readings taken at five fixed points: 0.25%, 0.5%, 0.75%, 1.0%, and 1.25%. The detection system is described including light source, cameras, and photocell detectors. The temperature control and the calibration of the chamber are discussed.

  1. The current status of fluoride salt cooled high temperature reactor (FHR) technology and its overlap with HIF target chamber concepts

    NASA Astrophysics Data System (ADS)

    Scarlat, Raluca O.; Peterson, Per F.

    2014-01-01

    The fluoride salt cooled high temperature reactor (FHR) is a class of fission reactor designs that use liquid fluoride salt coolant, TRISO coated particle fuel, and graphite moderator. Heavy ion fusion (HIF) can likewise make use of liquid fluoride salts, to create thick or thin liquid layers to protect structures in the target chamber from ablation by target X-rays and damage from fusion neutron irradiation. This presentation summarizes ongoing work in support of design development and safety analysis of FHR systems. Development work for fluoride salt systems with application to both FHR and HIF includes thermal-hydraulic modeling and experimentation, salt chemistry control, tritium management, salt corrosion of metallic alloys, and development of major components (e.g., pumps, heat exchangers) and gas-Brayton cycle power conversion systems. In support of FHR development, a thermal-hydraulic experimental test bay for separate effects (SETs) and integral effect tests (IETs) was built at UC Berkeley, and a second IET facility is under design. The experiments investigate heat transfer and fluid dynamics and they make use of oils as simulant fluids at reduced scale, temperature, and power of the prototypical salt-cooled system. With direct application to HIF, vortex tube flow was investigated in scaled experiments with mineral oil. Liquid jets response to impulse loading was likewise studied using water as a simulant fluid. A set of four workshops engaging industry and national laboratory experts were completed in 2012, with the goal of developing a technology pathway to the design and licensing of a commercial FHR. The pathway will include experimental and modeling efforts at universities and national laboratories, requirements for a component test facility for reliability testing of fluoride salt equipment at prototypical conditions, requirements for an FHR test reactor, and development of a pre-conceptual design for a commercial reactor.

  2. Exposure chamber

    DOEpatents

    Moss, Owen R.; Briant, James K.

    1983-01-01

    An exposure chamber includes an imperforate casing having a fluid inlet at the top and an outlet at the bottom. A single vertical series of imperforate trays is provided. Each tray is spaced on all sides from the chamber walls. Baffles adjacent some of the trays restrict and direct the flow to give partial flow back and forth across the chambers and downward flow past the lowermost pan adjacent a central plane of the chamber.

  3. Experimentally Induced Pulpal Lesion and Substance P Expression: Effect of Ketoprofen—A Preliminary Study

    PubMed Central

    Abbate, Gian Marco; Sacerdote, Paola; Amodeo, Giada; Mangano, Alessandro; Levrini, Luca

    2016-01-01

    Objectives. To evaluate substance P (SP) and the effect of ketoprofen administration, a nonsteroidal anti-inflammatory drug (NSAID), on SP in the pulp of upper third molars with experimentally induced pulpal lesion. Materials and Methods. A sample of 20 young systemically healthy adults of both sexes, nonsmokers, with a healthy upper third molar to extract for orthodontic purposes, was selected. Prior to the procedure, an inflammatory process was generated by mechanical exposure of the pulp. After 15 minutes, the pulp was collected using a sterile barbed broach. SP levels were determined by using a commercially available enzyme immunoassay (ELISA) kit. The subjects were randomly divided into two groups: group 1 received a dose of ketoprofen 30 minutes prior to the experimental procedure. The subjects of group 2 did not receive any kind of drug administration. The patients were asked to complete a diary on the postoperative pain. Results. No statistically significant difference could be detected in SP expression between the two groups. In group 1, pain manifestation was significantly delayed in comparison with group 2. Conclusions. Preventive administration of ketoprofen did not significantly affect the pulpal levels of SP but resulted in a significantly postponed manifestation of pain after extraction. PMID:27034673

  4. Prevalence of Referred Pain with Pulpal Origin in the Head, Face and Neck Region

    PubMed Central

    Mardani, Siamak; Eghbal, Mohammad Jafar; Baharvand, Maryam

    2008-01-01

    INTRODUCTION: This study was designed to evaluate the prevalence of referred pain with pulpal source in the head, face and neck region among patients referred to Dental School of Shahid Beheshti University MC, Tehran, Iran in 2004. MATERIALS AND METHODS: In this cross-sectional study, 100 patients (55 males and 45 females) referred to oral medicine department of Shahid Beheshti Dental School evaluated via clinical and radiographic examination to seek their pain sources and sites. Inclusion criteria were report of pain and a dental clinician accomplished detection of pain origin. Exclusion criteria were non-odontogenic painful diseases, advanced periodontal disease, and substantial carious lesions. Visual analogue scale (VAS) was used to score pain intensity; meanwhile the patients were asked to mark the painful sites on an illustrated head and neck mannequin. RESULTS: Sixty-five percent of patients reported pain in sites which diagnostically differed from the pain source. According to statistical analysis, duration (P<0.01), spontaneity (P<0.001) and quality (P<0.01) of pain influenced its referral nature, while sex and age of patients, kind of stimulus, throbbing and intensity of pain had no considerable effect on pain referral (P>0.05). CONCLUSION: The prevalence of referred pain with pulpal origin in the head, face and neck region is moderately high which requires precise diagnosis by dental practitioners. Some hallmarks of irreversible pulpitis (e.g. spontaneous and persistent pain after elimination of stimulus) are related to pain referral. PMID:24171013

  5. Experimentally Induced Pulpal Lesion and Substance P Expression: Effect of Ketoprofen-A Preliminary Study.

    PubMed

    Abbate, Gian Marco; Sacerdote, Paola; Amodeo, Giada; Mangano, Alessandro; Levrini, Luca

    2016-01-01

    Objectives. To evaluate substance P (SP) and the effect of ketoprofen administration, a nonsteroidal anti-inflammatory drug (NSAID), on SP in the pulp of upper third molars with experimentally induced pulpal lesion. Materials and Methods. A sample of 20 young systemically healthy adults of both sexes, nonsmokers, with a healthy upper third molar to extract for orthodontic purposes, was selected. Prior to the procedure, an inflammatory process was generated by mechanical exposure of the pulp. After 15 minutes, the pulp was collected using a sterile barbed broach. SP levels were determined by using a commercially available enzyme immunoassay (ELISA) kit. The subjects were randomly divided into two groups: group 1 received a dose of ketoprofen 30 minutes prior to the experimental procedure. The subjects of group 2 did not receive any kind of drug administration. The patients were asked to complete a diary on the postoperative pain. Results. No statistically significant difference could be detected in SP expression between the two groups. In group 1, pain manifestation was significantly delayed in comparison with group 2. Conclusions. Preventive administration of ketoprofen did not significantly affect the pulpal levels of SP but resulted in a significantly postponed manifestation of pain after extraction. PMID:27034673

  6. The Mars Chamber

    NASA Video Gallery

    The Mars chamber is a box about the size of a refrigerator that re-creates the temperatures, pressures, and atmosphere of the Martian surface, essentially creating a Mars environment on Earth! Scie...

  7. Exposure chamber

    DOEpatents

    Moss, Owen R.

    1980-01-01

    A chamber for exposing animals, plants, or materials to air containing gases or aerosols is so constructed that catch pans for animal excrement, for example, serve to aid the uniform distribution of air throughout the chamber instead of constituting obstacles as has been the case in prior animal exposure chambers. The chamber comprises the usual imperforate top, bottom and side walls. Within the chamber, cages and their associated pans are arranged in two columns. The pans are spaced horizontally from the walls of the chamber in all directions. Corresponding pans of the two columns are also spaced horizontally from each other. Preferably the pans of one column are also spaced vertically from corresponding pans of the other column. Air is introduced into the top of the chamber and withdrawn from the bottom. The general flow of air is therefore vertical. The effect of the horizontal pans is based on the fact that a gas flowing past the edge of a flat plate that is perpendicular to the flow forms a wave on the upstream side of the plate. Air flows downwardly between the chamber walls and the outer edges of the pan. It also flows downwardly between the inner edges of the pans of the two columns. It has been found that when the air carries aerosol particles, these particles are substantially uniformly distributed throughout the chamber.

  8. Comparison of the Booster Interface Temperature in Stainless Steel (SS) V-Channel Versus the Aluminum (Al) Y-Channel Primer Chamber Assemblies (PCAs). Volume 2; Appendices

    NASA Technical Reports Server (NTRS)

    Garcia, Roberto; Saulsberry, Regor L.

    2011-01-01

    NASA's Technical Fellow for Propulsion, requested a technical assessment of the performance improvement achieved by the introduction of the stainless steel (SS) V-channel compared to the aluminum (Al) Y-channel Primer Chamber Assembly (PCA) design. The SS V-channel PCA was developed for NASA's Mars Science Laboratory (MSL) Project. The principle focus of the assessment was to measure the transient temperature at the booster interface with both designs. This document contains the Appendices to the Volume I main report.

  9. Pulp-temperature increases after selective ablation of caries by KTP:NdYAG laser

    NASA Astrophysics Data System (ADS)

    Nammour, S.; Kowalyk, Kenneth; Valici, Ch.; Guillaume, Patrick

    1997-05-01

    The aim of this investigation is to define optimal parameters of KTP laser irradiation during caries removal. 12 decayed human teeth, recently extracted were used. Their rot canals were prepared for insertion of a thermocouple probe into the pulp chamber. The demineralized tissues have been colored by Acid Red 52 before proceeding to different conditions of irradiation. Pulpal temperature increases were found under the following parameters with 15 seconds continuous lasing: 400mw, 0.10 m sec pulse width, PRR temperature to get back to its baseline.

  10. A multipurpose ultra-high vacuum-compatible chamber for in situ X-ray surface scattering studies over a wide range of temperature and pressure environment conditions

    NASA Astrophysics Data System (ADS)

    Ferrer, P.; Rubio-Zuazo, J.; Heyman, C.; Esteban-Betegón, F.; Castro, G. R.

    2013-03-01

    A low/high temperature (60-1000K) and pressure (10-10-3x103 mbar) "baby chamber", specially adapted to the grazing-incidence X-ray scattering station, has been designed, developed and installed at the Spanish CRG BM25 SpLine beamline at European Synchrotron Radiation Facility. The chamber has a cylindrical form with 100 mm of diameter, built on a 360° beryllium nipple of 150 mm height. The UHV equipment and a turbo pump are located on the upper part of the chamber to leave a wide solid angle for exploring reciprocal space. The chamber features 4 CF16 and 5 CF40 ports for electrical feed through and leak valves, ion gun, etc. The heat exchanger is a customized compact LN2 (or LHe) continuous flow cryostat. The sample is mounted on a Mo support on the heat exchanger, which has in the back side a BORALECTRIC® Heater Elements. Experiments of surfaces/interfaces/ multilayer materials, thin films or single crystals in a huge variety of environments can be performed, also in situ studies of growth or evolution of the samples. Data measurement can be collected with a punctual and a bi-dimensional detector, being possible to simultaneously use them.

  11. Wire chamber

    DOEpatents

    Atac, Muzaffer

    1989-01-01

    A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

  12. Vertical two chamber reaction furnace

    DOEpatents

    Blaugher, R.D.

    1999-03-16

    A vertical two chamber reaction furnace is disclosed. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

  13. Vertical two chamber reaction furnace

    DOEpatents

    Blaugher, Richard D.

    1999-03-16

    A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

  14. The Mobile Chamber

    NASA Technical Reports Server (NTRS)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

    A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

  15. Soybean leaf hydraulic conductance does not acclimate to growth at elevated [CO2] or temperature in growth chambers or in the field

    PubMed Central

    Locke, Anna M.; Sack, Lawren; Bernacchi, Carl J.; Ort, Donald R.

    2013-01-01

    Background and Aims Leaf hydraulic properties are strongly linked with transpiration and photosynthesis in many species. However, it is not known if gas exchange and hydraulics will have co-ordinated responses to climate change. The objective of this study was to investigate the responses of leaf hydraulic conductance (Kleaf) in Glycine max (soybean) to growth at elevated [CO2] and increased temperature compared with the responses of leaf gas exchange and leaf water status. Methods Two controlled-environment growth chamber experiments were conducted with soybean to measure Kleaf, stomatal conductance (gs) and photosynthesis (A) during growth at elevated [CO2] and temperature relative to ambient levels. These results were validated with field experiments on soybean grown under free-air elevated [CO2] (FACE) and canopy warming. Key results In chamber studies, Kleaf did not acclimate to growth at elevated [CO2], even though stomatal conductance decreased and photosynthesis increased. Growth at elevated temperature also did not affect Kleaf, although gs and A showed significant but inconsistent decreases. The lack of response of Kleaf to growth at increased [CO2] and temperature in chamber-grown plants was confirmed with field-grown soybean at a FACE facility. Conclusions Leaf hydraulic and leaf gas exchange responses to these two climate change factors were not strongly linked in soybean, although gs responded to [CO2] and increased temperature as previously reported. This differential behaviour could lead to an imbalance between hydraulic supply and transpiration demand under extreme environmental conditions likely to become more common as global climate continues to change. PMID:23864003

  16. IONIZATION CHAMBER

    DOEpatents

    Redman, W.C.; Shonka, F.R.

    1958-02-18

    This patent describes a novel ionization chamber which is well suited to measuring the radioactivity of the various portions of a wire as the wire is moved at a uniform speed, in order to produce the neutron flux traverse pattern of a reactor in which the wire was previously exposed to neutron radiation. The ionization chamber of the present invention is characterized by the construction wherein the wire is passed through a tubular, straight electrode and radiation shielding material is disposed along the wire except at an intermediate, narrow area where the second electrode of the chamber is located.

  17. Temperature rise during experimental light-activated bleaching.

    PubMed

    Klaric, Eva; Rakic, Mario; Sever, Ivan; Tarle, Zrinka

    2015-02-01

    The purpose of this study was to evaluate the surface and intrapulpal temperatures after treatments with different bleaching gels subjected to different types of light activation. A K-type thermocouple and infrared thermometer were used to measure the temperature increase during the 15- or 30-min treatment period. Light-emitting diode with a center wavelength of 405 nm (LED405), organic light-emitting diode (OLED), and femtosecond laser were tested and compared to ZOOM2. The tooth surface was treated with five bleaching agents and Vaseline which served as a control.The generalized estimating equation (GEE) model was applied for testing the differences in temperature increase. The ZOOM2 light source led to the largest increase in mean pulpal and tooth surface temperatures of 21.1 and 22.8 °C, followed by focused femtosecond laser which increased the pulpal and surface temperatures by up to 15.7 and 16.8 °C. Treatments with unfocused femtosecond laser, LED405, and OLED induced significantly lower mean temperature increases (p < 0.001 for each comparison with ZOOM2 and focused femtosecond laser), both in the pulp chamber (up to 2.7, 2.5, and 1.4 °C) and at the tooth surface (up to 3.2, 3.4, and 1.8 °C). Significant differences between pulp chamber and tooth surface measurements were obtained for all types of bleaching gel, during treatments with ZOOM2 (p < 0.001), LED405 (p < 0.001), and unfocused (p < 0.001) and focused femtosecond laser (p ≤ 0.002). Different bleaching agents or Vaseline can serve as an isolating layer. Focused femtosecond laser and ZOOM2 produced large temperature increases in the pulp chamber and at the tooth surface. Caution is advised when using these types of light activation, while LED405, OLED, and unfocused femtosecond laser could be safely used. PMID:23780710

  18. Penetration of the pulp chamber by bleaching agents in teeth restored with various restorative materials.

    PubMed

    Gökay, O; Yilmaz, F; Akin, S; Tunçbìlek, M; Ertan, R

    2000-02-01

    It is thought that externally applied bleaching agents may penetrate into the pulp chamber. This study was conducted to evaluate the diffusion of peroxide bleaching agents into the pulp chamber of teeth restored with various restorative materials. Sixty-five human extracted anterior maxillary teeth were separated into the 13 groups containing 5 teeth. Five teeth (control group) were not subjected to any cavity preparation and restoration. Standardized class V cavities were prepared in the other 60 teeth and restored using composite resin (Charisma), polyacid modified composite resin (Dyract), or resin-modified glass ionomer cement (Vitremer). All teeth were sectioned 3 mm apical to the cementoenamel junction to remove the intracoronal pulp tissue, and the pulp chamber was filled with acetate buffer to absorb and stabilize any peroxide that might penetrate. Vestibular crown surfaces of teeth in the experimental groups were subjected to four different bleaching agents for 30 min at 37 degrees C, whereas the teeth in the control groups were exposed only to distilled water. Then the acetate buffer solution in the pulp chamber of each tooth was removed, and the pulp chamber of each tooth was rinsed with 100 ml of distilled water twice. Leukocrystal violet and enzyme horseradish peroxidase were added to the mixture of the acetate buffer and rinse water. The optical density of the resulting blue solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. Higher hydrogen peroxide concentrations resulted in a higher pulpal peroxide penetration. The highest pulpal peroxide penetration was found in resin-modified glass ionomer cement groups, whereas composite resin groups showed the lowest pulpal peroxide penetration. PMID:11194380

  19. Temperature changes inside the molar pulp chamber and on the enamel and root surfaces induced by the CO2 laser beam, in vitro

    NASA Astrophysics Data System (ADS)

    Anic, Ivica; Dzubur, A.; Skala, Karolj; Sutalo, Jozo

    1993-12-01

    The application of the CO2 laser continuous wave to hard dental tissue causes temperature changes on the impact area, on the adjacent area and inside the pulp chamber. The purpose of this study was to investigate the thermal effects induced by the CO2 laser continuous wave, and the temperature flow through adjacent areas. Forty healthy molars, 15 molars with class II amalgam restoration and 10 canines with cervical caries extracted for periodontal reasons were irradiated with laser beam. On the occlusal surface the class I preparation was made just beyond the dentine-enamel junction. Temperature changes were measured at the enamel, root surface and at the cross section of the previously prepared holes 3 mm in diameter which were made 2 mm above the bifurcation level.

  20. Iridium-Coated Rhenium Combustion Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

    1994-01-01

    Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

  1. Ionization chamber

    DOEpatents

    Walenta, Albert H.

    1981-01-01

    An ionization chamber has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionize the gas.

  2. Ionization chamber

    DOEpatents

    Walenta, A.H.

    An ionization chamber is described which has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionizes the gas.

  3. Pulpal and micro-organism responses to two experimental dental bonding systems.

    PubMed

    Blosser, R L; Rupp, N W; Stanley, H R; Bowen, R L

    1989-03-01

    Several new bonding systems have been reported that promote strong adhesion. This in vivo study involves treatment with two experimental bonding systems of Class V cavity preparations in the teeth of three Macaca fascicularis primates and reports the pulpal responses and degree of micro-organism invasion associated with each treatment. In each monkey, the teeth in the upper left quadrant were treated with the experimental solution, containing 2.5% aluminum nitrate + 1.5% oxalic acid + 4.9% NPG, followed by application of PMDM and Silux XL composite. The lower right quadrant was treated with the experimental solution, containing 5.7% NPG + 2.4% nitric acid, followed by PMDM and Silux XL composite. The upper right and lower left quadrants were treated with clinical materials to establish positive and negative controls. After four, 25, and 59 days, the teeth were removed and underwent routine histological and bacteriological evaluation. Slight pathological conditions were noted for superficial and deep responses, but all values approached 0.0 by the 59th day. Micro-organisms were seen under only 12% of the restorations. Both experimental systems appear to be safe for human clinical trials. PMID:2691304

  4. Automated Electrostatics Environmental Chamber

    NASA Technical Reports Server (NTRS)

    Calle, Carlos; Lewis, Dean C.; Buchanan, Randy K.; Buchanan, Aubri

    2005-01-01

    The Mars Electrostatics Chamber (MEC) is an environmental chamber designed primarily to create atmospheric conditions like those at the surface of Mars to support experiments on electrostatic effects in the Martian environment. The chamber is equipped with a vacuum system, a cryogenic cooling system, an atmospheric-gas replenishing and analysis system, and a computerized control system that can be programmed by the user and that provides both automation and options for manual control. The control system can be set to maintain steady Mars-like conditions or to impose temperature and pressure variations of a Mars diurnal cycle at any given season and latitude. In addition, the MEC can be used in other areas of research because it can create steady or varying atmospheric conditions anywhere within the wide temperature, pressure, and composition ranges between the extremes of Mars-like and Earth-like conditions.

  5. Effects of removing adhesive from tooth surfaces by Er:YAG laser and a composite bur on enamel surface roughnessand pulp chamber temperature

    PubMed Central

    Yassaei, Sogra; Aghili, Hossein; Joshan, Neda

    2015-01-01

    Background: At the end of fixed orthodontic treatment, the remnant of adhesive should be eliminated from the tooth surface. The purpose of this study was to compare the effect of three methods of removing adhesive on enamel surface roughness, dental pulp temperature, and also on the time spent. Materials and Methods: The brackets on 90 extracted teeth were debonded using bracket removal pliers. A thermocouple sensor was fitted on the buccal wall of the pulp chamber through access cavity to measure thermal changes during adhesive removal. The residue of adhesive was eliminated from enamel surface of teeth by either tungsten carbide bur, erbium-doped yttrium aluminum garnet laser, or fiber reinforced composite bur. Scanning electron micrographs images were taken to assess the roughness of enamel surface. The time spent for adhesive removal was recorded as well. Chi-square test was used to evaluate the remnants of adhesive and enamel surface roughness; t-test and also repeated measurement analysis of variance were applied at P < 0.05 to compare the thermal changes of the pulp chamber and time spent between the methods of surface treatment. Results: The results of surface roughness were significantly different (P < 0.001). The pulp temperature changed significantly (P < 0.001). Tungsten carbide bur increased the temperature by 5.5°C significantly slower than reinforced composite bur (P = 0.004), however removed the adhesive residue faster than two other methods although not significantly (P = 0.069). Conclusion: Within the limitations of this study, fiber reinforced composite bur created the smoothest enamel surface while Er:YAG laser the roughest. Tungsten carbide and composite burs generated more heat compared to Er:YAG laser. In addition, tungsten carbide bur was the fastest and Er:YAG laser the slowest devices to remove adhesive residue. PMID:26005466

  6. Fast-response cloud chamber

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.

    1977-01-01

    Wall structure keeps chambers at constant, uniform temperature, yet allows them to be cooled rapidly if necessary. Wall structure, used in fast-response cloud chamber, has surface heater and coolant shell separated by foam insulation. It is lightweight and requires relatively little power.

  7. Magma chambers

    NASA Technical Reports Server (NTRS)

    Marsh, Bruce D.

    1989-01-01

    Recent observational and theoretical investigations of terrestrial magma chambers (MCs) are reviewed. Consideration is given to the evidence for MCs with active convection and crystal sorting, problems of direct MC detection, theoretical models of MC cooling, the rheology and dynamics of solidification fronts, crystal capture and differentiation, convection with solidification, MC wall flows, and MC roof melting. Diagrams, graphs, and a list of problems requiring further research are provided.

  8. Pulpal safety of a 9.6-μm TEA CO2 laser used for caries prevention

    NASA Astrophysics Data System (ADS)

    Goodis, Harold E.; Fried, Daniel; Featherstone, John D. B.

    2002-06-01

    Lasers are used for several procedures involving hard and soft tissues of the oral cavity. Included in those procedures is the use of the CO2 laser to alter the surface structure of tooth enamel to render it more resistant to caries. A new 9.6micrometers wavelength TEA CO2 laser (Argu Photonics, Jpiter, FL) has been investigated as a device that can be used for this procedure without harming the dental pulp. Erupted, caries and restoration free third molars (n=24) were used in the experiment. Teeth were irradiated at an incident fluence of 1.5J/cm2 and a repetition rate of 10Hz and a spot size 1mm in diameter. At the low and high settings, 200 to 400 pulses were delivered at 12mJ per pulse for a total energy of 2.4 or 4.8J delivered for 20 or 40 seconds respectively. Other teeth were subjected to a sham dental procedure (positive control) or no procedure (negative control). Prior to testing, radiographs were taken of all teeth, and they were tested pulpally using heat, cold and electricity to determine vitality. The teeth were removed either immediately or at one week or one month after testing. They were bioprepared and examined histologically for signs of inflammation. Only one tooth developed symptoms of sensitivity to cold for 10 days following exposure to the high power level. The sensitivity was of fleeting duration and was judged to be reversible pulpitis. All teeth tested responded normally at pretesting and pre-extraction time periods. Histological examination disclosed no indication of an inflammatory response in the pulp tissue. All sections appeared normal with no changes seen in the normal pulpal morphology. We conclude that the 9.6 micrometers wavelength laser causes no pulpal damage at the energy levels used and can be used safely for caries prevention treatments.

  9. Measurements of VOC/SVOC emission factors from burning incenses in an environmental test chamber: influence of temperature, relative humidity, and air exchange rate.

    PubMed

    Manoukian, A; Buiron, D; Temime-Roussel, B; Wortham, H; Quivet, E

    2016-04-01

    This study investigates the influence of three environmental indoor parameters (i.e., temperature, relative humidity, and air exchange rate) on the emission of 13 volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) during incense burning. Experiments have been carried out using an environmental test chamber. Statistical results from a classical two-level full factorial design highlight the predominant effect of ventilation on emission factors. The higher the ventilation, the higher the emission factor. Moreover, thanks to these results, an estimation of the concentration range for the compounds under study can be calculated and allows a quick look of indoor pollution induced by incense combustion. Carcinogenic substances (i.e., benzene, benzo(a)pyrene, and formaldehyde) produced from the incense combustion would be predicted in typical living indoors conditions to reach instantaneous concentration levels close to or higher than air quality exposure threshold values. PMID:26614451

  10. CONTINUOUSLY SENSITIVE BUBBLE CHAMBER

    DOEpatents

    Good, R.H.

    1959-08-18

    A radiation detector of the bubble chamber class is described which is continuously sensitive and which does not require the complex pressure cycling equipment characteristic of prior forms of the chamber. The radiation sensitive element is a gas-saturated liquid and means are provided for establishing a thermal gradient across a region of the liquid. The gradient has a temperature range including both the saturation temperature of the liquid and more elevated temperatures. Thus a supersaturated zone is created in which ionizing radiations may give rise to visible gas bubbles indicative of the passage of the radiation through the liquid. Additional means are provided for replenishing the supply of gas-saturated liquid to maintaincontinuous sensitivity.

  11. Warmer temperatures stimulate respiration and reduce net ecosystem productivity in a northern Great Plains grassland: Analysis of CO2 exchange in automatic chambers

    NASA Astrophysics Data System (ADS)

    Flanagan, L. B.

    2013-12-01

    The interacting effects of altered temperature and precipitation are expected to have significant consequences for ecosystem net carbon storage. Here I report the results of an experiment that evaluated the effects of elevated temperature and altered precipitation on ecosystem CO2 exchange in a northern Great Plains grassland, near Lethbridge, Alberta Canada. Open-top chambers were used to establish an experiment in 2012 with three treatments (control, warmed, warmed plus 50% of normal precipitation input). A smaller experiment with only the two temperature treatments (control and warmed) was conducted in 2013. Continuous half-hourly net CO2 exchange measurements were made using nine automatic chambers during May-October in both years. My objectives were to determine the sensitivity of the ecosystem carbon budget to temperature and moisture manipulations, and to test for direct and indirect effects of the environmental changes on ecosystem CO2 exchange. The experimental manipulations resulted primarily in a significant increase in air temperature in the warmed treatment plots. A cumulative net loss of carbon or negative net ecosystem productivity (NEP) occurred during May through September in the warmed treatment (NEP = -659 g C m-2), while in the control treatment there was a cumulative net gain of carbon (NEP = +50 g C m-2). An eddy covariance system that operated at the site, over a footprint region that was not influenced by the experimental treatments, also showed a net gain of carbon by the ecosystem. The reduced NEP was due to higher plant and soil respiration rates in the warmed treatment that appeared to be caused by a combination of: (i) higher carbon substrate availability indirectly stimulating soil respiration in the warmed relative to the control treatment, and (ii) a strong increase in leaf respiration likely caused by a shift in electron partitioning to the alternative pathway respiration in the warmed treatment, particularly when exposed to high

  12. Small rocket flowfield diagnostic chambers

    NASA Technical Reports Server (NTRS)

    Morren, Sybil; Reed, Brian

    1993-01-01

    Instrumented and optically-accessible rocket chambers are being developed to be used for diagnostics of small rocket (less than 440 N thrust level) flowfields. These chambers are being tested to gather local fluid dynamic and thermodynamic flowfield data over a range of test conditions. This flowfield database is being used to better understand mixing and heat transfer phenomena in small rockets, influence the numerical modeling of small rocket flowfields, and characterize small rocket components. The diagnostic chamber designs include: a chamber design for gathering wall temperature profiles to be used as boundary conditions in a finite element heat flux model; a chamber design for gathering inner wall temperature and static pressure profiles; and optically-accessible chamber designs, to be used with a suite of laser-based diagnostics for gathering local species concentration, temperature, density, and velocity profiles. These chambers were run with gaseous hydrogen/gaseous oxygen (GH2/GO2) propellants, while subsequent versions will be run on liquid oxygen/hydrocarbon (LOX/HC) propellants. The purpose, design, and initial test results of these small rocket flowfield diagnostic chambers are summarized.

  13. An in vitro comparison of adhesive techniques and rotary instrumentation on shear bond strength of nanocomposite with simulated pulpal pressure

    PubMed Central

    Hegde, Jayshree; Sravanthi, Y

    2011-01-01

    Aim: The aim of this study is to evaluate the shear bond strength of composite to tooth using different adhesive techniques and rotary instruments under simulated pulpal pressure. Materials and Methods: Sixty extracted human molars were randomly divided into two groups of 30 samples each (group I and II), according to the adhesive technique followed (i.e. total etch and self etch groups). Each group was further divided into two sub-groups (Sub-groups A and B) of 15 samples each according to the cutting instrument (diamond abrasive or carbide burs) used. Class II cavities were made with diamond abrasive or carbide burs, and restored with nano-composite under positive intra-pulpal pressure. Shear bond strength of the specimens were recorded simultaneously. Results: After statistical evaluation using two-way ANOVA and t-test, the mean shear bond strength values of the groups are as follows: Group IA- 4.69 MPa, Group IB-6.15 MPa, Group IIA-4.3 MPa, and Group IIB-6.24 MPa. It was seen that group IIB showed highest bond strength followed by group IB. Group II A showed the least bond strength. Conclusions: Within the limitations of the study, diamond abrasive gave better bond strength than carbide bur with both the adhesive techniques. PMID:22025823

  14. Novel chamber to measure equilibrium soil-air partitioning coefficients of low-volatility organic chemicals under conditions of varying temperature and soil moisture.

    PubMed

    Wolters, André; Linnemann, Volker; Smith, Kilian E C; Klingelmann, Eva; Park, Byung-Jun; Vereecken, Harry

    2008-07-01

    The need to determine soil-air partitioning coefficients (K(SA)) of low-volatility organic chemicals as a measure of their distribution in the soil surface after release into the environment resulted in the development of a novel chamber system, which has been filed for patent. A major advantage of this pseudo-static system is that sufficient time can be factored into the experiment to ensure that the system has achieved equilibrium. In a highly precise method, the air is collected in adsorption tubes and subsequently liberated in a thermodesorption system for the quantitation of the adsorbed compound. The precision of the method is great enough that even the effects of temperature and soil moisture on the soil-air partitioning of very low-volatility compounds can be quantified. Because of analytical detection limits, quantitation of these influences has not been possible to date. Functionality of the setup was illustrated by measurements on the fungicide fenpropimorph. K(SA) values of fenpropimorph displayed a negative relationship with temperature and soil moisture. The type of application (spraying or incorporation) and the use of formulated compounds was shown to have a major impact on the measured K(SA) values. Comparison with calculations using an estimation method revealed that the use of experimentally determined K(SA) values will facilitate a more adequate consideration of volatilization in recent model approaches. PMID:18678019

  15. Acute pulpal-alveolar cellulitis syndrome. IV. Clinical parameters, demographics, and affirmation of a traditional etiologic theory. Part 2.

    PubMed

    Matusow, R J

    1986-01-01

    The Part 1 report revealed the microbiologic etiology and introduced the oxidation-reduction potential (Eh) as a major factor in acute cellulitis exacerbations during endodontic therapy. Facultative streptococci were the predominant group of microbes specifically isolated. This Part 2 study revealed a 9.5% incidence of cellulitis exacerbations in patients during endodontic treatment of 168 primarily intact nonvital teeth. These teeth were usually asymptomatic, manifesting radiographic periapical lesions without fistulous tracts and necrotic canals. This category of pulpal periapical inflammation is virtually the only type of tooth that is predisposed to cellulitis exacerbations. A frequency distribution of the 34 permanent teeth studied revealed a spectrum of mandibular and maxillary molars, premolars, and anterior teeth involved with the exacerbations. Sex and age did not appear to be factors. Further clinical evidence is cited, which support the concept of altering the tissue oxidation-reduction potential as the prime etiologic factor in favoring the growth of aerobic microbial pathogens. PMID:3456147

  16. Preliminary report on use of CO2 laser treatment of traumatic pulpal exposure in dogs: a clinical study

    NASA Astrophysics Data System (ADS)

    Wilder-Smith, Petra B. B.; Peavy, George M.; Nielsen, David; Arrastia-Jitosho, Anna-Marie A.; Berns, Michael W.

    1997-05-01

    The objective of this study was to evaluate carbon-dioxide laser surgical treatment of pulpal exposures in canine patients. Seventeen permanent teeth with exposures of less than or equal to 48 h were randomly allocated to receive either (1) localized laser pulp surgery to remove all compromised soft tissues or (2) localized pulp surgery using a large round sterile bur under sterile saline irrigation. Single laser pulses were used at 0.01 s pulse duration, 1.0 s pulse interval, a spot size of 0.004 cm2 and an energy density of 276 J/cm2. Exposures were dressed with CaOH and glass ionomer. Clinical and radiographic evaluations were performed by one blinded clinician 4, 12, 24 and 52 weeks after treatment using standard scales of 0-(-1). Fifteen/seventeen laser-treated teeth assessed over greater than or equal to 1 year post-treatment remained clinically and radiographically healthy.

  17. National Ignition Facility Target Chamber

    SciTech Connect

    Wavrik, R W; Cox, J R; Fleming, P J

    2000-10-05

    On June 11, 1999 the Department of Energy dedicated the single largest piece of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The ten (10) meter diameter aluminum target high vacuum chamber will serve as the working end of the largest laser in the world. The output of 192 laser beams will converge at the precise center of the chamber. The laser beams will enter the chamber in two by two arrays to illuminate 10 millimeter long gold cylinders called hohlraums enclosing 2 millimeter capsule containing deuterium, tritium and isotopes of hydrogen. The two isotopes will fuse, thereby creating temperatures and pressures resembling those found only inside stars and in detonated nuclear weapons, but on a minute scale. The NIF Project will serve as an essential facility to insure safety and reliability of our nation's nuclear arsenal as well as demonstrating inertial fusion's contribution to creating electrical power. The paper will discuss the requirements that had to be addressed during the design, fabrication and testing of the target chamber. A team from Sandia National Laboratories (SNL) and LLNL with input from industry performed the configuration and basic design of the target chamber. The method of fabrication and construction of the aluminum target chamber was devised by Pitt-Des Moines, Inc. (PDM). PDM also participated in the design of the chamber in areas such as the Target Chamber Realignment and Adjustment System, which would allow realignment of the sphere laser beams in the event of earth settlement or movement from a seismic event. During the fabrication of the target chamber the sphericity tolerances had to be addressed for the individual plates. Procedures were developed for forming, edge preparation and welding of individual plates. Construction plans were developed to allow the field construction of the target chamber to occur parallel to other NIF construction activities. This was

  18. Dual-purpose chamber-cooling system

    NASA Technical Reports Server (NTRS)

    Fraze, R. E.

    1968-01-01

    Inexpensive, portable system was designed for cooling small environmental test chambers with a temperature-controlled gas stream evaporated from a cryogenic liquid. The system reduces the temperature of a chamber to any desired point in a fraction of the time required by previous systems.

  19. Evaluation of temperature increase during in-office bleaching.

    PubMed

    Mondelli, Rafael Francisco Lia; Soares, Ana Flávia; Pangrazio, Eugenio Gabriel Kegler; Wang, Linda; Ishikiriama, Sergio Kiyoshi; Bombonatti, Juliana Fraga Soares

    2016-04-01

    The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser), a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05). Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C). The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C). The addition of a bleaching gel led to a higher increase in intrapulpal temperatures. PMID:27119761

  20. Evaluation of temperature increase during in-office bleaching

    PubMed Central

    MONDELLI, Rafael Francisco Lia; SOARES, Ana Flávia; PANGRAZIO, Eugenio Gabriel Kegler; WANG, Linda; ISHIKIRIAMA, Sergio Kiyoshi; BOMBONATTI, Juliana Fraga Soares

    2016-01-01

    ABSTRACT The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser), a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05). Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C). The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C). The addition of a bleaching gel led to a higher increase in intrapulpal temperatures. PMID:27119761

  1. A new miniature hydrostatic pressure chamber for microscopy. Strain- free optical glass windows facilitate phase-contrast and polarized- light microscopy of living cells. Optional fixture permits simultaneous control of pressure and temperature

    PubMed Central

    1975-01-01

    This paper describes the development of a miniature, temperature- controlled, stainless steel pressure chamber which uses strain-free optical glass for windows. It is directly adaptable to standard phase- contrast and polarized-light microscopes and requires a minimum amount of equipment to generate and measure pressure. Birefringence retardation (BR) og 0.1 nm up to 3,000 psi, 0.4 nm up to 5,000 psi and 1.0 nm up to 10,000 psi can be detected over a 0.75-mm central field with two strain-free Leitz 20 times UM objectives, one used as a condenser. In phase-contrast studies a Nikon DML 40 times phase objective and Zeiss model IS long working-distance phase condenser were used, with little deterioration of image quality or contrast at pressures as high as 12,000 psi. The actual design process required a synthesis of various criteria which may be categorized under four main areas of consideration: (a) specimen physiology; (b) constraints imposed by available optical equipment and standard microscope systems; (c) mechanical strength and methods for generating pressure; and (d) optical requirements of the chamber windows. Procedures for using the chambers, as well as methods for shifting and controlling the temperature within the chamber, are included. PMID:1094021

  2. Spectrophotometric evaluation of peroxide penetration into the pulp chamber from whitening strips and gel: An in vitro study

    PubMed Central

    Bharti, Ramesh; Wadhwani, KK

    2013-01-01

    Aim: To investigate pulp chamber penetration of different concentration of hydrogen peroxide. Materials and Methods: Fifty extracted human maxillary central incisor teeth were taken and grouped into five (n = 10). All teeth were cut approximately 3 mm apical to the cemento-enamel junction. Pulp was removed and the pulp chamber filled with acetate buffer. Buccal crown surfaces of teeth in the experimental groups were subjected to whitening strip and paint on whitener gel. Control group teeth were exposed to distilled water. The acetate buffer solution in each tooth was then transferred to a glass test tube after 30 min. Leuco-crystal violet dye and enzyme horse radish peroxidase were added. The optical density of resultant blue color in the tubes was measured by UV-visible spectrophotometer. The values were converted into microgram equivalents of hydrogen peroxide. Results: The results were evaluated statistically using nonparametric Mann–Whitney U test. Whitening strip showed the lowest pulpal peroxide penetration whereas paint on whitener gel showed highest pulpal peroxide penetration. Conclusion: This study demonstrate that peroxide is readily penetrate into the pulp chamber of teeth. PMID:23716964

  3. CARS study of linewidths of the Q-branch of hydrogen molecules at high temperatures in a pulsed high-pressure H{sub 2}-O{sub 2} combustion chamber

    SciTech Connect

    Vereschagin, Konstantin A; Vereschagin, Alexey K; Smirnov, Valery V; Stelmakh, O M; Fabelinskii, V I; Clauss, W; Klimenko, D N; Oschwald, M

    2005-03-31

    The results of measurements of individual line widths of the Q-branch of a hydrogen molecule and the corresponding coefficients of broadening caused by collisions with water molecules at T = 2700 K in a repetitively pulsed high-pressure (50-200 atm) hydrogen-oxygen combustion chamber are presented. CARS spectra of individual Q{sub 1}-Q{sub 7} hydrogen lines, pressure pulses, and the broadband CARS spectra of the entire Q-branch of hydrogen are recorded simultaneously during a single laser pulse. The shape of line profiles was analysed using a Fabry-Perot interferometer. The temperature in the volume being probed was determined from the 'broadband' CARS spectra. The entire body of the experimental results gives information on the spectral linewidths, temperature and pressure in the combustion chamber during CARS probing. (laser applications and other topics in quantum electronics)

  4. Comparison of the Booster Interface Temperature in Stainless Steel (SS) V-Channel versus the Aluminum (Al) Y-Channel Primer Chamber Assemblies (PCAs). Volume 1; Technical Assessment Report

    NASA Technical Reports Server (NTRS)

    Garcia, Roberto; Saulsberry, Regor L.

    2011-01-01

    NASA's Technical Fellow for Propulsion, requested a technical assessment of the performance improvement achieved by the introduction of the stainless steel (SS) V-channel compared to the aluminum (Al) Y-channel Primer Chamber Assembly (PCA) design. The SS V-channel PCA was developed for NASA's Mars Science Laboratory (MSL) Project. The principle focus of the assessment was to measure the transient temperature at the booster interface with both designs. This document contains the findings of the assessment.

  5. Emulsion Chamber Technology Experiment (ECT)

    NASA Technical Reports Server (NTRS)

    Gregory, John C.; Takahashi, Yoshiyuki

    1996-01-01

    The experimental objective of Emulsion Chamber Technology (ECT) was to develop space-borne emulsion chamber technology so that cosmic rays and nuclear interactions may subsequently be studied at extremely high energies with long exposures in space. A small emulsion chamber was built and flown on flight STS-62 of the Columbia in March 1994. Analysis of the several hundred layers of radiation-sensitive material has shown excellent post-flight condition and suitability for cosmic ray physics analysis at much longer exposures. Temperature control of the stack was 20 +/-1 C throughout the active control period and no significant deviations of temperature or pressure in the chamber were observed over the entire mission operations period. The unfortunate flight attitude of the orbiter (almost 90% Earth viewing) prevented any significant number of heavy particles (Z greater than or equal to 10) reaching the stack and the inverted flow of shower particles in the calorimeter has not allowed evaluation of absolute primary cosmic ray-detection efficiency nor of the practical time limits of useful exposure of these calorimeters in space to the level of detail originally planned. Nevertheless, analysis of the observed backgrounds and quality of the processed photographic and plastic materials after the flight show that productive exposures of emulsion chambers are feasible in low orbit for periods of up to one year or longer. The engineering approaches taken in the ECT program were proven effective and no major environmental obstacles to prolonged flight are evident.

  6. Simulation of Layered Magma Chambers.

    ERIC Educational Resources Information Center

    Cawthorn, Richard Grant

    1991-01-01

    The principles of magma addition and liquid layering in magma chambers can be demonstrated by dissolving colored crystals. The concepts of density stratification and apparent lack of mixing of miscible liquids is convincingly illustrated with hydrous solutions at room temperature. The behavior of interstitial liquids in "cumulus" piles can be…

  7. Reducing the risk of sensitivity and pulpal complications after the placement of crowns and fixed partial dentures.

    PubMed

    Brännström, M

    1996-10-01

    Sensitivity after cementation of a crown with glass-ionomer cement is often attributed to an adverse effect on the pulp by the luting agent. Most permanent restorative materials in common use today do not tend to irritate the pulp; the main cause of pulpal damage is infection, the bacteria originating in the smear layer or deep in the dental tubules, inaccessible to caries-excavating procedures. A poorly fitting provisional crown may expose cut dentin to the oral fluids, and mechanical trauma caused by frictional heat during preparation may also damage the pulp. The following precautions are recommended during precementation procedures to reduce the risk of an inflammatory response in the pulp: (1) The provisional crown should be well fitting, covering cervical dentin but not impinging on the periodontal tissues. The permanent crown should be cemented as soon as possible. (2) The superficial smear layer should be removed and the dentinal surface should be treated with an antibacterial solution before the provisional crown is placed. (3) To decrease dentinal permeability under the provisional crown, the dentinal surface should be covered with a liner that can be easily removed before final cementation. (4) to ensure optimal mircomechanical bonding, the dentinal surface should be thoroughly cleaned, and the dentin should be kept moist until cementation. (5) The occlusion should be carefully checked before cementation of the crown. PMID:9180403

  8. Periodontal and pulpal conditions of abutment teeth. Status after four to eight years following the incorporation of fixed reconstructions.

    PubMed

    Reichen-Graden, S; Lang, N P

    1989-01-01

    In the present retrospective clinical study, 58 patients were examined 4 to 8 years (median 77 months) following the incorporation of a fixed reconstruction. No regular maintenance care had been provided during the interval period. The periodontal conditions represented by the Plaque Control Record (PCR), the Gingival Index (GI) and pocket probing depths were examined on 182 abutment teeth of 94 reconstructions. Pulpal vitality and periapical pathology were assessed clinically as well as radiographically. The periodontal parameters of the abutment teeth were compared with homologous contralateral uncrowned teeth. Significantly higher plaque prevalence, gingival indices, and pocket probing depths were found in the crowned teeth. Also, bleeding on probing was observed more frequently whenever the crown margins were located subgingivally. At the end of the interval period, 3.7% of the originally vital abutments had lost their vitality. A technical failure rate of 7.4% with no apparent differences between conventional and extension bridges was noted. This study indicates that even with precise marginal fit and in the absence of a regular maintenance program, the supragingival location of the crown margin is more favourable than the subgingival location for the maintenance of oral health. PMID:2701195

  9. Evaluation of pulpal response of deciduous teeth after direct pulp capping with bioactive glass and mineral trioxide aggregate

    PubMed Central

    Haghgoo, Roza; Ahmadvand, Motahare

    2016-01-01

    Aim: The aim of this study was to evaluate the pulpal response of primary teeth after direct pulp capping (DPC) with two biocompatible materials namely mineral trioxide aggregate (MTA) and bioactive glass (BAG). Settings and Design: This study was a randomized clinical trial. Materials and Methods: A total of 22 healthy primary canine teeth scheduled for extraction for orthodontic reasons were selected. The teeth were divided into two groups of 11 and underwent DPC. The exposure sites were randomly capped with MTA or BAG in the two groups. After 2 months, the teeth were extracted and prepared for histopathologic evaluation. Statistical Analysis: The data were analyzed using Fisher's exact test. Results: In the BAG group, inflammation was seen in three patients; internal resorption and abscess were not seen at all. In the MTA group, inflammation was seen in one patient and internal resorption and abscess were not seen in any patient. Fisher's exact test showed no significant difference between the two groups (P > 0.05). Dentinal bridge formation was noted in five patients in the BAG group and six patients in the MTA group. No significant difference was observed between the BAG and MTA groups using Chi-square analysis (P = 0.67). Conclusion: Based on the results of this study, MTA and BAG can be used for DPC of primary teeth.

  10. Calculation of gas temperature at the outlet of the combustion chamber and in the air-gas channel of a gas-turbine unit by data of acceptance tests in accordance with ISO

    NASA Astrophysics Data System (ADS)

    Kostyuk, A. G.; Karpunin, A. P.

    2016-01-01

    This article describes a high accuracy method enabling performance of the calculation of real values of the initial temperature of a gas turbine unit (GTU), i.e., the gas temperature at the outlet of the combustion chamber, in a situation where manufacturers do not disclose this information. The features of the definition of the initial temperature of the GTU according to ISO standards were analyzed. It is noted that the true temperatures for high-temperature GTUs is significantly higher than values determined according to ISO standards. A computational procedure for the determination of gas temperatures in the air-gas channel of the gas turbine and cooling air consumptions over blade rims is proposed. As starting equations, the heat balance equation and the flow mixing equation for the combustion chamber are assumed. Results of acceptance GTU tests according to ISO standards and statistical dependencies of required cooling air consumptions on the gas temperature and the blade metal are also used for calculations. An example of the calculation is given for one of the units. Using a developed computer program, the temperatures in the air-gas channel of certain GTUs are calculated, taking into account their design features. These calculations are performed on the previously published procedure for the detailed calculation of the cooled gas turbine subject to additional losses arising because of the presence of the cooling system. The accuracy of calculations by the computer program is confirmed by conducting verification calculations for the GTU of the Mitsubishi Comp. and comparing results with published data of the company. Calculation data for temperatures were compared with the experimental data and the characteristics of the GTU, and the error of the proposed method is estimated.

  11. Neutron Detection via Bubble Chambers

    SciTech Connect

    Jordan, David V.; Ely, James H.; Peurrung, Anthony J.; Bond, Leonard J.; Collar, J. I.; Flake, Matthew; Knopf, Michael A.; Pitts, W. K.; Shaver, Mark W.; Sonnenschein, Andrew; Smart, John E.; Todd, Lindsay C.

    2005-10-06

    The results of a Pacific Northwest National Laboratory (PNNL) exploratory research project investigating the feasibility of fast neutron detection using a suitably prepared and operated, pressure-cycled bubble chamber are described. The research was conducted along two parallel paths. Experiments with a slow pressure-release Halon chamber at the Enrico Fermi Institute at the University of Chicago showed clear bubble nucleation sensitivity to an AmBe neutron source and insensitivity to the 662 keV gammas from a 137Cs source. Bubble formation was documented via high-speed (1000 frames/sec) photography, and the acoustic signature of bubble formation was detected using a piezo-electric transducer element mounted on the base of the chamber. The chamber’s neutron sensitivity as a function of working fluid temperature was mapped out. The second research path consisted of the design, fabrication, and testing of a fast pressure-release Freon-134a chamber at PNNL. The project concluded with successful demonstrations of the PNNL chamber’s AmBe neutron source sensitivity and 137Cs gamma insensitivity. The source response tests of the PNNL chamber were documented with high-speed photography.

  12. Ionization-chamber smoke detector system

    DOEpatents

    Roe, Robert F.

    1976-10-19

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system is designed to reduce false alarms caused by fluctuations in ambient temperature. Means are provided for periodically firing the gas discharge triode and each time recording the triggering voltage required. A computer compares each triggering voltage with its predecessor. The computer is programmed to energize an alarm if the difference between the two compared voltages is a relatively large value indicative of particulates in the measuring chamber and to disregard smaller differences typically resulting from changes in ambient temperature.

  13. Involvement of TRPA1 in the cinnamaldehyde-induced pulpal blood flow change in the feline dental pulp

    PubMed Central

    Kim, Dokyung; Lee, Moon-Hwan

    2016-01-01

    Objectives The purpose of this study was to investigate the involvement of TRPA1 in the cinnamaldehyde-induced pulpal blood flow (PBF) change in the feline dental pulp. Materials and Methods Mandibles of eight cats were immobilized and PBF was monitored with a laser Doppler flowmetry at the mandibular canine tooth. To evaluate the effect of cinnamaldehyde on PBF, cinnamaldehyde was injected into the pulp through the lingual artery at a constant rate for 60 seconds. As a control, a mixture of 70% ethanol and 30% dimethyl sulfoxide (DMSO, vehicle) was used. To evaluate the involvement of transient receptor potential ankyrin 1 (TRPA1) in PBF change, AP18, a specific TRPA1 antagonist, was applied into the pulp through the Class V dentinal cavity followed by cinnamaldehyde-administration 3 minutes later. The paired variables of experimental data were statistically analyzed using paired t-test. A p value of less than 0.05 was considered as statistically significant. Results Administration of cinnamaldehyde (0.5 mg/kg, intra-arterial [i.a.]) induced significant increases in PBF (p < 0.05). While administration of a TRPA1 antagonist, AP18 (2.5 - 3.0 mM, into the dentinal cavity [i.c.]) caused insignificant change of PBF (p > 0.05), administration of cinnamaldehyde (0.5 mg/kg, i.a.) following the application of AP18 (2.5 - 3.0 mM, i.c.) resulted in an attenuation of PBF increase from the control level (p < 0.05). As a result, a TRPA1 antagonist, AP18 effectively inhibited the vasodilative effect of cinnamaldehyde (p < 0.05). Conclusions The result of the present study provided a functional evidence that TRPA1 is involved in the mechanism of cinnamaldehyde-induced vasodilation in the feline dental pulp. PMID:27508162

  14. A new multi-wavelength optical-plethysmograph for quantitative determination of pulpal hemoglobin content and oxygen level using green and near-infrared LEDs

    NASA Astrophysics Data System (ADS)

    Kakino, S.; Miwa, Z.; Kirimoto, A.; Ohuchi, K.; Takatani, S.; Takagi, Y.

    2007-02-01

    A new multi-wavelength optical-plethysmograph has been designed to study the relation between the transmitted optical density (OD) of the tooth vs. hemoglobin (Hb) content and oxygen saturation (SO II) of the pulpal blood using the 467, 506, 522 and 810 nm light emitting diodes (LEDs). The experimental model utilized the extracted human upper incisor where the pulp cavity was filled with the blood having various values of Hb and SO II. A resin cap was made to fit the tooth crown and optical fibers for transmission measurement. The LEDs were pulsed sequentially at 520 Hz with the pulse duration of 240 μs. The OD as a function of Hb for the isosbestic wavelengths of 506 and 522 nm increased almost linearly from 8.0 to 11.0 for Hb changing from 0.0 (saline control) to 2.5 g/dL, but beyond 2.5 g/dL no change was observed. At 810 nm, the OD increased linearly till Hb of 13.4 g/dL, but its change was much smaller with 1.0 OD per 13.4 g/dL. As for SO II, the OD at 467 nm with Hb of 1.0 g/dL that simulated the mean pulpal Hb content in vivo varied by about 1.0 for SO II changing from 100 to 40%. The OD change with respect to Hb change at 506 and 522 nm showed better sensitivity than that at 810 nm. The combination of 467 and 506 or 522 nm wavelengths can provide a noninvasive measurement of both pulpal Hb content and SO II to diagnose pulp vitality of teeth in vivo.

  15. Space Chambers for Crop Treatment

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Vacuum chambers, operated by McDonnell Douglas Corporation to test spacecraft, can also be used to dry water-soaked records. The drying temperature is low enough to allow paper to dry without curling or charging. Agricultural crops may also be dried using a spinoff system called MIVAC, which has proven effective in drying rice, wheat, soybeans, corn, etc. The system is energy efficient and can incorporate a sanitation process for destroying insects without contamination.

  16. Utilizing Chamber Data for Developing and Validating Climate Change Models

    NASA Technical Reports Server (NTRS)

    Monje, Oscar

    2012-01-01

    Controlled environment chambers (e.g. growth chambers, SPAR chambers, or open-top chambers) are useful for measuring plant ecosystem responses to climatic variables and CO2 that affect plant water relations. However, data from chambers was found to overestimate responses of C fluxes to CO2 enrichment. Chamber data may be confounded by numerous artifacts (e.g. sidelighting, edge effects, increased temperature and VPD, etc) and this limits what can be measured accurately. Chambers can be used to measure canopy level energy balance under controlled conditions and plant transpiration responses to CO2 concentration can be elucidated. However, these measurements cannot be used directly in model development or validation. The response of stomatal conductance to CO2 will be the same as in the field, but the measured response must be recalculated in such a manner to account for differences in aerodynamic conductance, temperature and VPD between the chamber and the field.

  17. Theoretical Performance of Hydrogen-Oxygen Rocket Thrust Chambers

    NASA Technical Reports Server (NTRS)

    Sievers, Gilbert K.; Tomazic, William A.; Kinney, George R.

    1961-01-01

    Data are presented for liquid-hydrogen-liquid-oxygen thrust chambers at chamber pressures from 15 to 1200 pounds per square inch absolute, area ratios to approximately 300, and percent fuel from about 8 to 34 for both equilibrium and frozen composition during expansion. Specific impulse in vacuum, specific impulse, combustion-chamber temperature, nozzle-exit temperature, characteristic velocity, and the ratio of chamber-to-nozzle-exit pressure are included. The data are presented in convenient graphical forms to allow quick calculation of theoretical nozzle performance with over- or underexpansion, flow separation, and introduction of the propellants at various initial conditions or heat loss from the combustion chamber.

  18. Cyclic fatigue analysis of rocket thrust chambers. Volume 1: OFHC copper chamber low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Miller, R. W.

    1974-01-01

    A three-dimensional finite element elasto-plastic strain analysis was performed for the throat section of a regeneratively cooled rocket combustion chamber. The analysis employed the RETSCP finite element computer program. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the chamber operating cycle. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen combustion chamber which was fatigue tested to failure. The computed strain range at typical chamber operating conditions was used in conjunction with oxygen-free, high-conductivity (OHFC) copper isothermal fatigue test data to predict chamber low-cycle fatigue life.

  19. Target chambers for gammashpere

    SciTech Connect

    Carpenter, M.P.; Falout, J.W.; Nardi, B.G.

    1995-08-01

    One of our responsibilities for Gammasphere, was designing and constructing two target chambers and associated beamlines to be used with the spectrometer. The first chamber was used with the early implementation phase of Gammasphere, and consisted of two spun-Al hemispheres welded together giving a wall thickness of 0.063 inches and a diameter of 12 inches.

  20. High resolution drift chambers

    SciTech Connect

    Va'vra, J.

    1985-07-01

    High precision drift chambers capable of achieving less than or equal to 50 ..mu..m resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs.

  1. Three dimensional thrust chamber life prediction

    NASA Technical Reports Server (NTRS)

    Armstrong, W. H.; Brogren, E. W.

    1976-01-01

    A study was performed to analytically determine the cyclic thermomechanical behavior and fatigue life of three configurations of a Plug Nozzle Thrust Chamber. This thrust chamber is a test model which represents the current trend in nozzle design calling for high performance coupled with weight and volume limitations as well as extended life for reusability. The study involved the use of different materials and material combinations to evaluate their application to the problem of low-cycle fatigue in the thrust chamber. The thermal and structural analyses were carried out on a three-dimensional basis. Results are presented which show plots of continuous temperature histories and temperature distributions at selected times during the operating cycle of the thrust chamber. Computed structural data show critical regions for low-cycle fatigue and the histories of strain within the regions for each operation cycle.

  2. Chamber Clearing First Principles Modeling

    SciTech Connect

    Loosmore, G

    2009-06-09

    LIFE fusion is designed to generate 37.5 MJ of energy per shot, at 13.3 Hz, for a total average fusion power of 500 MW. The energy from each shot is partitioned among neutrons ({approx}78%), x-rays ({approx}12%), and ions ({approx}10%). First wall heating is dominated by x-rays and debris because the neutron mean free path is much longer than the wall thickness. Ion implantation in the first wall also causes damage such as blistering if not prevented. To moderate the peak-pulse heating, the LIFE fusion chamber is filled with a gas (such as xenon) to reduce the peak-pulse heat load. The debris ions and majority of the x-rays stop in the gas, which re-radiates this energy over a longer timescale (allowing time for heat conduction to cool the first wall sufficiently to avoid damage). After a shot, because of the x-ray and ion deposition, the chamber fill gas is hot and turbulent and contains debris ions. The debris needs to be removed. The ions increase the gas density, may cluster or form aerosols, and can interfere with the propagation of the laser beams to the target for the next shot. Moreover, the tritium and high-Z hohlraum debris needs to be recovered for reuse. Additionally, the cryogenic target needs to survive transport through the gas mixture to the chamber center. Hence, it will be necessary to clear the chamber of the hot contaminated gas mixture and refill it with a cool, clean gas between shots. The refilling process may create density gradients that could interfere with beam propagation, so the fluid dynamics must be studied carefully. This paper describes an analytic modeling effort to study the clearing and refilling process for the LIFE fusion chamber. The models used here are derived from first principles and balances of mass and energy, with the intent of providing a first estimate of clearing rates, clearing times, fractional removal of ions, equilibrated chamber temperatures, and equilibrated ion concentrations for the chamber. These can be used

  3. Longitudinal changes of nerve conduction velocity, distal motor latency, compound motor action potential duration, and skin temperature during prolonged exposure to cold in a climate chamber.

    PubMed

    Maetzler, Walter; Klenk, Jochen; Becker, Clemens; Zscheile, Julia; Gabor, Kai-Steffen; Lindemann, Ulrich

    2012-09-01

    Changes of nerve conduction velocity (NCV), distal motor latency (DML), compound motor action potential (CMAP) duration, and skin temperature with regard to cold have been investigated by use of ice packs or cold water baths, but not after cooling of environmental temperature which has higher ecological validity. The aim of this study was to investigate these parameters during cooled room temperature. NCV, DML, and CMAP duration of the common fibular nerve, and skin temperature were measured in 20 healthy young females during exposure to 15°C room temperature, coming from 25°C room. We found that NCV decreased and DML increased linearly during 45 min observation time, in contrast to CMAP duration and skin temperature which changes followed an exponential curve. To the best of our knowledge, this is the first study investigating changes of these parameters during exposure to environmental cold. The results may pilot some new hypotheses and studies on physiological and pathological changes of the peripheral nervous system and skin to environmental cold, e.g., in elderly with peripheral neuropathies. PMID:22510085

  4. 45. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION DDD), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION DDD), VIEW LOOKING EAST. LEAD ENCLOSED PIPING IS DRAIN FROM BOILER CHAMBER No. 1 - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  5. Innovative Comparison of Transient Ignition Temperature at the Booster Interface, New Stainless Steel Pyrovalve Primer Chamber Assembly "V" (PCA) Design Versus the Current Aluminum "Y" PCA Design

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor L.; McDougle, Stephen H.; Garcia,Roberto; Johnson, Kenneth L.; Sipes, William; Rickman, Steven; Hosangadi, Ashvin

    2011-01-01

    An assessment of four spacecraft pyrovalve anomalies that occurred during ground testing was conducted by the NASA Engineering & Safety Center (NESC) in 2008. In all four cases, a common aluminum (Al) primer chamber assembly (PCA) was used with dual NASA Standard Initiators (NSIs) and the nearly simultaneous (separated by less than 80 microseconds) firing of both initiators failed to ignite the booster charge. The results of the assessment and associated test program were reported in AIAA Paper AIAA-2008-4798, NESC Independent Assessment of Pyrovalve Ground Test Anomalies. As a result of the four Al PCA anomalies, and the test results and findings of the NESC assessment, the Mars Science Laboratory (MSL) project team decided to make changes to the PCA. The material for the PCA body was changed from aluminum (Al) to stainless steel (SS) to avoid melting, distortion, and potential leakage of the NSI flow passages when the device functioned. The flow passages, which were interconnected in a Y-shaped configuration (Y-PCA) in the original design, were changed to a V-shaped configuration (V-PCA). The V-shape was used to more efficiently transfer energy from the NSIs to the booster. Development and qualification testing of the new design clearly demonstrated faster booster ignition times compared to the legacy AL Y-PCA design. However, the final NESC assessment report recommended that the SS V-PCA be experimentally characterized and quantitatively compared to the Al Y-PCA design. This data was deemed important for properly evaluating the design options for future NASA projects. This test program has successfully quantified the improvement of the SS V-PCA over the Al Y-PCA. A phase B of the project was also conducted and evaluated the effect of firing command skew and enlargement of flame channels to further assist spacecraft applications.

  6. Sleeve reaction chamber system

    SciTech Connect

    Northrup, M. Allen; Beeman, Barton V.; Benett, William J.; Hadley, Dean R.; Landre, Phoebe; Lehew, Stacy L.; Krulevitch, Peter A.

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  7. Outgassing measurement of the aluminum alloy UHV chamber

    NASA Technical Reports Server (NTRS)

    Miyamoto, M.; Itoh, T.; Komaki, S.; Narushima, K.; Ishimaru, H.

    1986-01-01

    A large vacuum chamber (580 mm diameter) was fabricated from an aluminum alloy surface treated by a special process normally used on small chambers. The chamber was tested unbaked and baked at various temperatures, pressures, and holding periods. The chamber was filled with N2 gas, and the outgassing rate was measured after one hour. Then the ultimate pressure was measured. Outgassing rates for baked and unbaked groups were compared. It is concluded that the same surface treatment technique can be used on both large and small chambers produced by the same special extrusion process.

  8. Portable Ethylene Oxide Sterilization Chamber

    PubMed Central

    Songer, J. R.; Mathis, R. G.

    1969-01-01

    A portable ethylene oxide sterilization chamber was designed, constructed, and tested for use in the sterilization of embolectomy catheters. The unit can accommodate catheters up to 40 inches (101.6 cm) in length and can be operated for less than 4 cents per cycle. A constant concentration of 500 mg of ethylene oxide per liter of space and holding periods of 4 and 6 hr at 43 and 22 C, respectively, were adequate when tested with B. subtilis spores. The estimated cost of construction was $165.00. If temperature control is unnecessary, the cost is approximately $80.00. Images PMID:4977644

  9. Endodontic applications of a short pulsed FR Nd:YAG dental laser: photovaporization of extruded pulpal tissue following traumatic fractures of two maxillary central incisors--a clinical trial repor

    NASA Astrophysics Data System (ADS)

    Gregg, Robert H., II

    1992-06-01

    Historically, many techniques have been attempted in the search for a satisfactory and consistent treatment of inflamed, painful, hyperemic pulpal tissue. Present techniques attempting to achieve profound local anesthesia in such tissue, have not been satisfactory. Local anesthesia techniques acceptable to the patient with painful hyperemic pulpal tissue, has eluded previous technology. The subsequent treatment of hyperemic tissue without sufficient anesthesia primarily involves undesirable invasive mechanical/surgical procedures. Described in this clinical trial is a technique using free running (FR) pulsed, Nd:YAG laser energy to ablate soft tooth pulpal tissue--a technique employed after conventional endodontic methods failed. A free running pulsed, FR Nd:YAG dental laser was successfully used at 20 pulses per second and 1.25 watts to photovaporize endodontic pulpal tissue (pulpectomy) to allow a conventional endodontic file to extirpate the remaining soft tissue remnants and access the root apex. Also described in this paper is the 'hot-tip' effect of contact fiber laser surgery. This clinical trial achieved the immediate, short term objective of endodontic soft tissue removal via photovaporization, without pain reported by the patient. The pulsed FR Nd:YAG dental laser used as described in this clinical report appears to be a very safe and very effective technique; offers a treatment alternative to traditional therapy that suggests high patient acceptance; and is significantly less stressful for the doctor and staff than traditional treatment options. Long-term, controlled scientific and clinical studies are necessary to establish the safety and efficacy of both the helium-neon energy for visualization and the low-watt pulsed FR Nd:YAG energy for photovaporization of soft endodontic pulpal tissue within the root canal. Research is especially needed to understand the effects of a low-watt, pulsed FR, Nd:YAG laser on the activity of osteoclasts and odontoclasts

  10. Liquid rocket engine self-cooled combustion chambers

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Self-cooled combustion chambers are chambers in which the chamber wall temperature is controlled by methods other than fluid flow within the chamber wall supplied from an external source. In such chambers, adiabatic wall temperature may be controlled by use of upstream fluid components such as the injector or a film-coolant ring, or by internal flow of self-contained materials; e.g. pyrolysis gas flow in charring ablators, and the flow of infiltrated liquid metals in porous matrices. Five types of self-cooled chambers are considered in this monograph. The name identifying the chamber is indicative of the method (mechanism) by which the chamber is cooled, as follows: ablative; radiation cooled; internally regenerative (Interegen); heat sink; adiabatic wall. Except for the Interegen and heat sink concepts, each chamber type is discussed separately. A separate and final section of the monograph deals with heat transfer to the chamber wall and treats Stanton number evaluation, film cooling, and film-coolant injection techniques, since these subjects are common to all chamber types. Techniques for analysis of gas film cooling and liquid film cooling are presented.

  11. Improved Rhenium Thrust Chambers

    NASA Technical Reports Server (NTRS)

    O'Dell, John Scott

    2015-01-01

    Radiation-cooled bipropellant thrust chambers are being considered for ascent/ descent engines and reaction control systems on various NASA missions and spacecraft, such as the Mars Sample Return and Orion Multi-Purpose Crew Vehicle (MPCV). Currently, iridium (Ir)-lined rhenium (Re) combustion chambers are the state of the art for in-space engines. NASA's Advanced Materials Bipropellant Rocket (AMBR) engine, a 150-lbf Ir-Re chamber produced by Plasma Processes and Aerojet Rocketdyne, recently set a hydrazine specific impulse record of 333.5 seconds. To withstand the high loads during terrestrial launch, Re chambers with improved mechanical properties are needed. Recent electrochemical forming (EL-Form"TM") results have shown considerable promise for improving Re's mechanical properties by producing a multilayered deposit composed of a tailored microstructure (i.e., Engineered Re). The Engineered Re processing techniques were optimized, and detailed characterization and mechanical properties tests were performed. The most promising techniques were selected and used to produce an Engineered Re AMBR-sized combustion chamber for testing at Aerojet Rocketdyne.

  12. A Histopathological Comparison of Pulpal Response to Chitra-CPC and Formocresol used as Pulpotomy Agents in Primary Teeth: A Clinical Trial.

    PubMed

    Ratnakumari, N; Thomas, Bijimol

    2012-01-01

    Preventive measures have helped to minimize the occurrence of dental caries. However, premature loss of primary teeth on account of dental caries still remains a common problem among children. The pulpotomy technique has been the choice for treating vital primary and young permanent teeth with carious, mechanical and traumatic pulp exposures. The ideal pulpotomy medicament should be bioinductive or at least biocompatible, bactericidal and harmless to the pulp and surrounding structures. It should also promote healing of the radicular pulp and prevent bacterial microleakage with the least interference in the physiological process of root resorption. Since the best criteria for judging the effectiveness of a medicament when used for vital pulp therapy is the response that it produces in the pulp. The purpose of the present study was to evaluate and compare the response of human pulp tissue to recently developed Indian material, Sree Chitra-Calcium Phosphate Cement (Chitra-CPC) and formocresol, used as pulpotomy agent in deciduous teeth. Chitra-CPC has been compared with formocresol, taking into account that formocresol is still considered the gold standard in primary tooth pulpotomy. The study was conducted among 10 children in the age group of 8 to 12 years focusing on 20 noncarious primary canines indicated for serial extraction. Each patient received two different pulpotomy procedures-one in each of the primary canines using formocresol and the other with Chitra-CPC as pulpotomy agents. After 70 days, the teeth were extracted and subjected to histological examination. The results did not reveal statistically significant difference between the two groups. But Chitra-CPC gave more favorable results, in respect of pulpal inflammation, dentin bridge formation, quality of dentin bridge and connective tissue in dentin bridge. How to cite this article: Ratnakumari N, Thomas B. A Histopathological Comparison of Pulpal Response to Chitra- CPC and Formocresol used as

  13. Thrust chamber material technology program

    NASA Technical Reports Server (NTRS)

    Andrus, J. S.; Bordeau, R. G.

    1989-01-01

    This report covers work performed at Pratt & Whitney on development of copper-based materials for long-life, reusable, regeneratively cooled rocket engine thrust chambers. The program approached the goal of enhanced cyclic life through the application of rapid solidification to alloy development, to introduce fine dispersions to strengthen and stabilize the alloys at elevated temperatures. After screening of alloy systems, copper-based alloys containing Cr, Co, Hf, Ag, Ti, and Zr were processed by rapid-solidification atomization in bulk quantities. Those bulk alloys showing the most promise were characterized by tensile testing, thermal conductivity testing, and elevated-temperature, low-cycle fatigue (LFC) testing. Characterization indicated that Cu- 1.1 percent Hf exhibited the greatest potential as an improved-life thrust chamber material, exhibiting LCF life about four times that of NASA-Z. Other alloys (Cu- 0.6 percent Zr, and Cu- 0.6 percent Zr- 1.0 percent Cr) exhibited promise for use in this application, but needed more development work to balance properties.

  14. Filament wound rocket motor chambers

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The design, analysis, fabrication and testing of a Kevlar-49/HBRF-55A filament wound chamber is reported. The chamber was fabricated and successfully tested to 80% of the design burst pressure. Results of the data reduction and analysis from the hydrotest indicate that the chamber design and fabrication techniques used for the chamber were adequate and the chamber should perform adequately in a static test.

  15. Automated soil gas monitoring chamber

    DOEpatents

    Edwards, Nelson T.; Riggs, Jeffery S.

    2003-07-29

    A chamber for trapping soil gases as they evolve from the soil without disturbance to the soil and to the natural microclimate within the chamber has been invented. The chamber opens between measurements and therefore does not alter the metabolic processes that influence soil gas efflux rates. A multiple chamber system provides for repetitive multi-point sampling, undisturbed metabolic soil processes between sampling, and an essentially airtight sampling chamber operating at ambient pressure.

  16. Cryogenic Chamber for Servo-Hydraulic Materials Testing

    NASA Technical Reports Server (NTRS)

    Francis, John J.; Tuttle, James

    2009-01-01

    A compact cryogenic test chamber can be cooled to approximately 5 to 6 Kelvin for materials testing. The system includes a temperature controller and multiple sensors to measure specimen temperature at different locations. The testing chamber provides a fast and easy method to perform materials testing at lower than liquid nitrogen temperature (77 K). The purpose of the chamber is to cool a composite lap shear specimen to approximately 20 K so that tensile test force and displacement data may be acquired at this cryogenic temperature range.

  17. Improved wire chamber

    DOEpatents

    Atac, M.

    1987-05-12

    An improved gas mixture for use with proportional counter devices, such as Geiger-Mueller tubes and drift chambers. The improved gas mixture provides a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor. 2 figs.

  18. Ultrasonic Drying Processing Chamber

    NASA Astrophysics Data System (ADS)

    Acosta, V.; Bon, J.; Riera, E.; Pinto, A.

    The design of a high intensity ultrasonic chamber for drying process was investigated. The acoustic pressure distribution in the ultrasonic drying chamber was simulated solving linear elastic models with attenuation for the acoustic-structure interaction. Together with the government equations, the selection of appropriate boundary conditions, mesh refinement, and configuration parameters of the calculation methods, which is of great importance to simulate adequately the process, were considered. Numerical solution, applying the finite element method (FEM), of acoustic-structure interactions involves to couple structural and fluid elements (with different degrees of freedom), whose solution implies several problems of hardware requirements and software configuration, which were solved. To design the drying chamber, the influence of the directivity of the drying open camera and the staggered reflectors over the acoustic pressure distribution was analyzed. Furthermore, to optimize the influence of the acoustic energy on the drying process, the average value of the acoustic energy distribution in the drying chamber was studied. This would determine the adequate position of the food samples to be dried. For this purpose, the acoustic power absorbed by the samples will be analyzed in later studies.

  19. Liquid Wall Chambers

    SciTech Connect

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  20. Numerical simulation of magma chamber dynamics.

    NASA Astrophysics Data System (ADS)

    Longo, Antonella; Papale, Paolo; Montagna, Chiara Paola; Vassalli, Melissa; Giudice, Salvatore; Cassioli, Andrea

    2010-05-01

    Magma chambers are characterized by periodic arrivals of deep magma batches that give origin to complex patterns of magma convection and mixing, and modify the distribution of physical quantities inside the chamber. We simulate the transient, 2D, multi-component homogeneous dynamics in geometrically complex dyke+chamber systems, by means of GALES, a finite element parallel C++ code solving mass, momentum and energy equations for multi-component homogeneous gas-liquid (± crystals) mixtures in compressible-to-incompressible flow conditions. Code validation analysis includes several cases from the classical engineering literature, corresponding to a variety of subsonic to supersonic gas-liquid flow regimes (see http://www.pi.ingv.it/~longo/gales/gales.html). The model allows specification of the composition of the different magmas in the domain, in terms of ten major oxides plus the two volatile species H2O and CO2. Gas-liquid thermodynamics are modeled by using the compositional dependent, non-ideal model in Papale et al. (Chem.. Geol., 2006). Magma properties are defined in terms of local pressure, temperature, and composition including volatiles. Several applications are performed within domains characterized by the presence of one or more magma chambers and one or more dykes, with different geometries and characteristic size from hundreds of m to several km. In most simulations an initial compositional interface is placed at the top of a feeding dyke, or at larger depth, with the deeper magma having a lower density as a consequence of larger volatile content. The numerical results show complex patterns of magma refilling in the chamber, with alternating phases of magma ingression and magma sinking from the chamber into the feeding dyke. Intense mixing takes place in feeding dykes, so that the new magma entering the chamber is always a mixture of the deep and the initially resident magma. Buoyant plume rise occurs through the formation of complex convective

  1. Miniature reaction chamber and devices incorporating same

    DOEpatents

    Mathies, Richard A.; Woolley, Adam T.

    2000-10-17

    The present invention generally relates to miniaturized devices for carrying out and controlling chemical reactions and analyses. In particular, the present invention provides devices which have miniature temperature controlled reaction chambers for carrying out a variety of synthetic and diagnostic applications, such as PCR amplification, nucleic acid hybridization, chemical labeling, nucleic acid fragmentation and the like.

  2. Comsol Simulations as a Tool in Validating a Measurement Chamber

    NASA Astrophysics Data System (ADS)

    Lakka, Antti; Sairanen, Hannu; Heinonen, Martti; Högström, Richard

    2015-12-01

    The Centre for Metrology and Accreditation (MIKES) is developing a temperature-humidity calibration system for radiosondes. The target minimum air temperature and dew-point temperature are -80° C and -90° C, respectively. When operating in this range, a major limiting factor is the time of stabilization which is mainly affected by the design of the measurement chamber. To find an optimal geometry for the chamber, we developed a numerical simulation method taking into account heat and mass transfer in the chamber. This paper describes the method and its experimental validation using two stainless steel chambers with different geometries. The numerical simulation was carried out using Comsol Multiphysics simulation software. Equilibrium states of dry air flow at -70° C with different inlet air flow rates were used to determine the geometry of the chamber. It was revealed that the flow is very unstable despite having relatively small Reynolds number values. Humidity saturation abilities of the new chamber were studied by simulating water vapor diffusion in the chamber in time-dependent mode. The differences in time of humidity stabilization after a step change were determined for both the new chamber model and the MIKES Relative Humidity Generator III (MRHG) model. These simulations were used as a validation of the simulation method along with experimental measurements using a spectroscopic hygrometer. Humidity saturation stabilization simulations proved the new chamber to be the faster of the two, which was confirmed by experimental measurements.

  3. 40 CFR 92.110 - Weighing chamber and micro-balance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Weighing chamber and micro-balance. 92... Weighing chamber and micro-balance. (a) Ambient conditions—(1) Temperature. The temperature of the chamber.... (b) Weighing balance specifications. The microbalance used to determine the weights of all...

  4. 40 CFR 92.110 - Weighing chamber and micro-balance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Weighing chamber and micro-balance. 92... Weighing chamber and micro-balance. (a) Ambient conditions—(1) Temperature. The temperature of the chamber.... (b) Weighing balance specifications. The microbalance used to determine the weights of all...

  5. 40 CFR 92.110 - Weighing chamber and micro-balance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Weighing chamber and micro-balance. 92... Weighing chamber and micro-balance. (a) Ambient conditions—(1) Temperature. The temperature of the chamber.... (b) Weighing balance specifications. The microbalance used to determine the weights of all...

  6. 40 CFR 92.110 - Weighing chamber and micro-balance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Weighing chamber and micro-balance. 92... Weighing chamber and micro-balance. (a) Ambient conditions—(1) Temperature. The temperature of the chamber.... (b) Weighing balance specifications. The microbalance used to determine the weights of all...

  7. 40 CFR 92.110 - Weighing chamber and micro-balance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Weighing chamber and micro-balance. 92... Weighing chamber and micro-balance. (a) Ambient conditions—(1) Temperature. The temperature of the chamber.... (b) Weighing balance specifications. The microbalance used to determine the weights of all...

  8. Multi-chamber deposition system

    DOEpatents

    Jacobson, Richard L.; Jeffrey, Frank R.; Westerberg, Roger K.

    1989-10-17

    A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

  9. Multi-chamber deposition system

    DOEpatents

    Jacobson, Richard L.; Jeffrey, Frank R.; Westerberg, Roger K.

    1989-06-27

    A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

  10. Combustor with fuel preparation chambers

    NASA Technical Reports Server (NTRS)

    Zelina, Joseph (Inventor); Myers, Geoffrey D. (Inventor); Srinivasan, Ram (Inventor); Reynolds, Robert S. (Inventor)

    2001-01-01

    An annular combustor having fuel preparation chambers mounted in the dome of the combustor. The fuel preparation chamber comprises an annular wall extending axially from an inlet to an exit that defines a mixing chamber. Mounted to the inlet are an air swirler and a fuel atomizer. The air swirler provides swirled air to the mixing chamber while the atomizer provides a fuel spray. On the downstream side of the exit, the fuel preparation chamber has an inwardly extending conical wall that compresses the swirling mixture of fuel and air exiting the mixing chamber.

  11. 50. BOILER CHAMBER No. 1, LOOKING SOUTHEAST BETWEEN CHAMBER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. BOILER CHAMBER No. 1, LOOKING SOUTHEAST BETWEEN CHAMBER AND ENCLOSURE (LOCATION III) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  12. 61. BOILER CHAMBER No. 2, LOOKING SOUTHWEST BETWEEN CHAMBER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    61. BOILER CHAMBER No. 2, LOOKING SOUTHWEST BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION PPP) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  13. 44. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION CCC), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION CCC), LOOKING NORTHEAST SHOWING DRAIN PIPE FROM SUMP - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  14. 41. AUXILIARY CHAMBER, CONCRETE ENCLOSURE CHAMBER AIR LOCK (EXTERIOR), LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. AUXILIARY CHAMBER, CONCRETE ENCLOSURE CHAMBER AIR LOCK (EXTERIOR), LOOKING NORTHEAST FROM SOUTHWEST CORNER (LOCATION AAA) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  15. 72. VISITOR'S CENTER, MODEL OF BOILER CHAMBER, AUXILIARY CHAMBER, REACTOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    72. VISITOR'S CENTER, MODEL OF BOILER CHAMBER, AUXILIARY CHAMBER, REACTOR AND CANAL (LOCATION T) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  16. Using a glass fiber separator in a single-chamber air-cathode microbial fuel cell shortens start-up time and improves anode performance at ambient and mesophilic temperatures.

    PubMed

    Zhang, Xiaoyuan; Liang, Peng; Shi, Juan; Wei, Jincheng; Huang, Xia

    2013-02-01

    A shorter start-up time and highly negative anode potentials are needed to improve single-chamber air-cathode microbial fuel cells (MFCs). Using a glass fiber separator reduced the start-up time from 10d to 8d at 20°C, and from 4d to 2d at 30°C, and enhanced coulombic efficiency (CE) from <60% to 89% (20°C) and 87% (30°C). Separators also reduced anode potentials by 20-190mV, charge transfer resistances by 76% (20°C) and 19% (30°C), and increased CV peak currents by 24% (20°C) and 8% (30°C) and the potential range for redox activity (-0.55 to 0.10mV vs. -0.49 to -0.24mV at 20°C). Using a glass fiber separator in an air-cathode MFC, combined with inoculation at a mesophilic temperature, are excellent strategies to shorten start-up time and to enhance anode performance and CE. PMID:23334007

  17. Visual-Inspection Probe For Cryogenic Chamber

    NASA Technical Reports Server (NTRS)

    Friend, Steve; Valenzuela, James; Yoshinaga, Jay

    1990-01-01

    Visual-inspection probe that resembles borescope enables observer at ambient temperature to view objects immersed in turbulent flow of liquid oxygen, liquid nitrogen, or other cryogenic fluid. Design of probe fairly conventional, except special consideration given to selection of materials and to thermal expansion to provide for expected range of operating temperatures. Penetrates wall of cryogenic chamber to provide view of interior. Similar probe illuminates scene. View displayed on video monitor.

  18. Three chamber negative ion source

    DOEpatents

    Leung, Ka-Ngo; Ehlers, Kenneth W.; Hiskes, John R.

    1985-01-01

    A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential.

  19. Multiwire proportional chamber development

    NASA Technical Reports Server (NTRS)

    Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

    1973-01-01

    The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

  20. Aerosol chamber study of optical constants and N2O5 uptake on supercooled H2SO4/H2O/HNO3 solution droplets at polar stratospheric cloud temperatures.

    PubMed

    Wagner, Robert; Naumann, Karl-Heinz; Mangold, Alexander; Möhler, Ottmar; Saathoff, Harald; Schurath, Ulrich

    2005-09-15

    The mechanism of the formation of supercooled ternary H(2)SO(4)/H(2)O/HNO(3) solution (STS) droplets in the polar winter stratosphere, i.e., the uptake of nitric acid and water onto background sulfate aerosols at T < 195 K, was successfully mimicked during a simulation experiment at the large coolable aerosol chamber AIDA of Forschungszentrum Karlsruhe. Supercooled sulfuric acid droplets, acting as background aerosol, were added to the cooled AIDA vessel at T = 193.6 K, followed by the addition of ozone and nitrogen dioxide. N(2)O(5), the product of the gas phase reaction between O(3) and NO(2), was then hydrolyzed in the liquid phase with an uptake coefficient gamma(N(2)O(5)). From this experiment, a series of FTIR extinction spectra of STS droplets was obtained, covering a broad range of different STS compositions. This infrared spectra sequence was used for a quantitative test of the accuracy of published infrared optical constants for STS aerosols, needed, for example, as input in remote sensing applications. The present findings indicate that the implementation of a mixing rule approach, i.e., calculating the refractive indices of ternary H(2)SO(4)/H(2)O/HNO(3) solution droplets based on accurate reference data sets for the two binary H(2)SO(4)/H(2)O and HNO(3)/H(2)O systems, is justified. Additional model calculations revealed that the uptake coefficient gamma(N(2)O(5)) on STS aerosols strongly decreases with increasing nitrate concentration in the particles, demonstrating that this so-called nitrate effect, already well-established from uptake experiments conducted at room temperature, is also dominant at stratospheric temperatures. PMID:16834200

  1. Combustion chamber struts can be effectively transpiration cooled

    NASA Technical Reports Server (NTRS)

    Palmer, G. H.

    1966-01-01

    Vapor-deposited sintering technique increases the feasible temperature range of transpiration-cooled structural members in combustion chambers. This technique produces a porous mass of refractory metal wires around a combustion chamber structural member. This mass acts as a transpiration-cooled surface for a thick-walled tube.

  2. Advanced thrust chamber designs

    NASA Technical Reports Server (NTRS)

    Dietrich, F. J.; Leach, A. E.

    1971-01-01

    A regeneratively cooled thrust chamber has been designed and fabricated, consisting of an inner TD nickel liner which was spin formed, welded, and machined and an outer shell of electroformed nickel. Coolant channels were produced in the outer surface of the inner liner by the electric discharge machining process before electroforming the shell. Accessory manifolds and piping were attached by welding. Manufacturing processes employed are described.

  3. Digital optical spark chambers

    NASA Technical Reports Server (NTRS)

    Evenson, Paul; Tuska, Evelyn

    1989-01-01

    The authors constructed and tested a prototype digital readout system for optical spark chambers using a linear, solid-state charge-coupled-device detector array. Position resolution of 0.013 mm (sigma) over a 25-cm field of view has been demonstrated. It is concluded that this technique should permit the construction of economical, lightweight and low-power trajectory hodoscopes for use in cosmic-ray instrumentation on balloons and in spacecraft.

  4. Performance of a transpiration-regenerative cooled rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Valler, H. W.

    1979-01-01

    The analysis, design, fabrication, and testing of a liquid rocket engine thrust chamber which is gas transpiration cooled in the high heat flux convergent portion of the chamber and water jacket cooled (simulated regenerative) in the barrel and divergent sections of the chamber are described. The engine burns LOX-hydrogen propellants at a chamber pressure of 600 psia. Various transpiration coolant flow rates were tested with resultant local hot gas wall temperatures in the 800 F to 1400 F range. The feasibility of transpiration cooling with hydrogen and helium, and the use of photo-etched copper platelets for heat transfer and coolant metering was successfully demonstrated.

  5. Effect of long-term simulated pulpal pressure on the bond strength and nanoleakage of resin-luting agents with different bonding strategies.

    PubMed

    de Alexandre, R S; Santana, V B; Kasaz, A C; Arrais, C A G; Rodrigues, J A; Reis, A F

    2014-01-01

    This study evaluated the effects of simulated hydrostatic pulpal pressure (SPP) on the microtensile bond strength (μTBS) to dentin and nanoleakage patterns produced by self-adhesive luting agents after 12 months. Three self-adhesive luting agents (RelyX Unicem [UN], RelyX U100 [UC], and Clearfil SA Luting [SA]) and three conventional luting agents (Rely X ARC [RX], Panavia F [PF], and a two-step self-etching adhesive system [Clearfil SE Bond] associated with Panavia F [PS]) were evaluated. One hundred twenty-three human molars were abraded to expose occlusal surfaces. Resin cements were used to lute cylindrical composite blocks to the teeth either subjected or not to SPP. Sixty specimens were subjected to 15 cm H2O of SPP for 24 hours before and 24 hours or 12 months after cementation procedures. Afterward, restored teeth were serially sectioned into beams with a cross-sectional area of 1 mm(2) at the bonded interface and were tested in tension (cross-head speed of 1 mm/min). Failure mode was determined using scanning electron microscopy (SEM). Data were statistically analyzed by three-way analysis of variance and post hoc Tukey test (p=0.05). Two additional teeth in each group were serially sectioned into 0.9-mm-thick slabs, which were submitted to a nanoleakage protocol with AgNO3 and analyzed with scanning and transmission electron microscopes. The μTBS values of the etch-and-rinse group (RX) were negatively influenced by SPP and long-term water storage with SPP. After 12 months, UC and SA presented premature failures in all specimens when submitted to SPP. SPP increased silver deposition in most groups in both evaluation times. The hydrostatic pulpal pressure effect was material dependent. The storage time without SPP did not affect bond strength. However, long-term SPP influenced the performance of the etch-and-rinse and self-adhesive cements regarding μTBS and nanoleakage pattern, except to UN. PMID:24502755

  6. The effects of extraction of pulpally involved primary teeth on weight, height and BMI in underweight Filipino children. A cluster randomized clinical trial

    PubMed Central

    2012-01-01

    Background Severe dental caries and the treatment thereof are reported to affect growth and well-being of young children. The objective of this study was to assess the effects of extraction of severely decayed pulpally involved primary teeth on weight and height in underweight preschool Filipino children. Methods Underweight preschool Filipino children with severe dental decay had their pulpally involved primary teeth extracted during a stepped wedge cluster randomized clinical trial. Day care centers were randomly divided into two groups; children from Group A day care centers received treatment as soon as practical, whereas children from Group B day care centers were treated four months after Group A. Clinical oral examinations using WHO criteria and the pufa-index were carried out. Anthropometric measurements were done on both groups immediately before treatment of Group A and at follow-up four months later. Height and weight z-scores were calculated using 2006 and 2007 WHO Growth Standards. Multilevel analysis was used to assess the effect of dental extractions on changes in anthropometric measurements after dental treatment. Results Data on 164 children (85 in Group A and 79 in Group B), mean age 59.9 months, were analyzed. Both groups gained weight and height during the trial period. Children in Group A significantly increased their BMI (p < 0.001), and their weight-for-age (p < 0.01) and BMI-for-age z-scores (p < 0.001) after dental treatment, whereas untreated children in Group B did not. Children in Group A had significantly more weight gain (p < 0.01) compared to untreated children in Group B. However, children in Group A had an inverse change in height gain (p < 0.001). Adjustment for the time interval between the two visits had little effect on the results. Conclusions The extraction of severely decayed primary teeth resulted in significant weight gain in underweight Filipino children. Untreated dental decay should be considered an

  7. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    NASA Astrophysics Data System (ADS)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2015-11-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOC) can be studied in detail. In PLUS all important enviromental parameters (e.g. temperature, PAR, soil RH etc.) are well-controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leafes of the plants is constructed such that gases are exposed to FEP Teflon film and other Teflon surfaces only to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 LED panels which have an emission strength up to 800 μmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOC) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light and temperature dependent BVOC emissions are studied using six Quercus Ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus Ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental set up and the utility of the newly added plant chamber.

  8. A new plant chamber facility, PLUS, coupled to the atmosphere simulation chamber SAPHIR

    NASA Astrophysics Data System (ADS)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2016-03-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been built and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow-through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees is mixed with synthetic air and transferred to the SAPHIR chamber, where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOCs) can be studied in detail. In PLUS all important environmental parameters (e.g., temperature, photosynthetically active radiation (PAR), soil relative humidity (RH)) are well controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leaves of the plants is constructed such that gases are exposed to only fluorinated ethylene propylene (FEP) Teflon film and other Teflon surfaces to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 light-emitting diode (LED) panels, which have an emission strength up to 800 µmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOCs) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light- and temperature- dependent BVOC emissions are studied using six Quercus ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental setup and the utility of the newly added plant chamber.

  9. Miniature microwave powered steam sterilization chamber

    NASA Astrophysics Data System (ADS)

    Atwater, James E.; Dahl, Roger W.; Garmon, Frank C.; Lunsford, Teddie D.; Michalek, William F.; Wheeler, Richard R., Jr.; Sauer, Richard L.

    1997-10-01

    A small device for the rapid ultrahigh temperature sterilization of surfaces is described. Microwave power generated by a 2.45 GHz magnetron is delivered via coaxial cable to a silicon carbide block housed within the chamber. Small quantities of water or aqueous hydrogen peroxide are introduced into the chamber. Upon application of power, the liquid flashes to vapor and superheats producing temperatures to 300 °C. The hot vapor permeates the enclosed space and contacts all exposed surfaces. Complete microbial kill of >10 6 colony forming units of the spore forming thermophile, Bacillus stearothermophilus, has been demonstrated using a variety of temperatures and exposure times in both steady state and thermal pulse modes of operation.

  10. Multi-anode ionization chamber

    DOEpatents

    Bolotnikov, Aleksey E.; Smith, Graham; Mahler, George J.; Vanier, Peter E.

    2010-12-28

    The present invention includes a high-energy detector having a cathode chamber, a support member, and anode segments. The cathode chamber extends along a longitudinal axis. The support member is fixed within the cathode chamber and extends from the first end of the cathode chamber to the second end of the cathode chamber. The anode segments are supported by the support member and are spaced along the longitudinal surface of the support member. The anode segments are configured to generate at least a first electrical signal in response to electrons impinging thereon.

  11. Wire chambers revisited.

    PubMed

    Ott, R J

    1993-04-01

    Detectors used for radioisotope imaging have, historically, been based on scintillating crystal/photomultiplier combinations in various forms. From the rectilinear scanner through to modern gamma cameras and positron cameras, the basic technology has remained much the same. Efforts to overcome the limitations of this form of technology have foundered on the inability to reproduce the required sensitivity, spatial resolution and sensitive area at acceptable cost. Multiwire proportional chambers (MWPCs) have long been used as position-sensitive charged particle detectors in nuclear and high-energy physics. MWPCs are large-area gas-filled ionisation chambers in which large arrays of fine wires are used to measure the position of ionisation produced in the gas by the passage of charged particles. The important properties of MWPCs are high-spatial-resolution, large-area, high-count-rate performance at low cost. For research applications, detectors several metres square have been built and small-area detectors have a charged particle resolution of 0.4 mm at a count rate of several million per second. Modification is required to MWPCs for nuclear medicine imaging. As gamma rays or X-rays cannot be detected directly, they must be converted into photo- or Compton scatter electrons. Photon-electron conversion requires the use of high atomic number materials in the body of the chamber. Pressurised xenon is the most useful form of "gas only" photon-electron convertor and has been used successfully in a gamma camera for the detection of gamma rays at energies below 100 keV. This camera has been developed specifically for high-count-rate first-pass cardiac imaging. This high-pressure xenon gas MWPC is the key to a highly competitive system which can outperform scintillator-based systems. The count rate performance is close to a million counts per second and the intrinsic spatial resolution is better than the best scintillator-based camera. The MWPC camera produces quantitative

  12. Review of wire chamber aging

    SciTech Connect

    Va'Vra, J.

    1986-02-01

    This paper makes an overview of the wire chamber aging problems as a function of various chamber design parameters. It emphasizes the chemistry point of view and many examples are drawn from the plasma chemistry field as a guidance for a possible effort in the wire chamber field. The paper emphasizes the necessity of variable tuning, the importance of purity of the wire chamber environment, as well as it provides a practical list of presently known recommendations. In addition, several models of the wire chamber aging are qualitatively discussed. The paper is based on a summary talk given at the Wire Chamber Aging Workshop held at LBL, Berkeley on January 16-17, 1986. Presented also at Wire Chamber Conference, Vienna, February 25-28, 1986. 74 refs., 18 figs., 11 tabs.

  13. Developmental changes in pulpal sensory innervation of rat incisors and molars shown on a single injection of the fluorescent dye AM1-43.

    PubMed

    Nishikawa, Sumio

    2007-12-01

    Developmental changes in pulpal innervation of rat incisors and molars were examined using the fluorescent styryl dye AM1-43, which labels sensory cells and nerves in vivo. From 2 to 40 days after birth, the animals were injected once with a small amount of AM1-43 solution (2 microg/g bodyweight). One day after the injection, the animals were killed and examined. In 3-day-old rats, neither incisors nor molars were innervated. In 7-day-old rats, the pulp of incisors and molars was innervated as indicated by fine intensely stained varicose sensory fibers and thicker intensely stained fibers running mostly along the blood vessels. In 15-, 27-, and 41-day-old rats, sensory nerve fibers neither passed through the odontoblast layer nor penetrated into the dentin in incisors, whereas the sensory nerve fibers penetrated into the coronal dentin through the odontoblast layers in molars. These results suggest that innervation of dental pulp is composed of two phases: (i) linear penetration of nerve fibers along blood vessels into the pulp space; and (ii) sprouting and extension of nerve fibers into coronal dentin. Innervation of the incisor pulp may stop at the first phase. PMID:18062152

  14. Microwave-assisted wet digestion with H2O2 at high temperature and pressure using single reaction chamber for elemental determination in milk powder by ICP-OES and ICP-MS.

    PubMed

    Muller, Edson I; Souza, Juliana P; Muller, Cristiano C; Muller, Aline L H; Mello, Paola A; Bizzi, Cezar A

    2016-08-15

    In this work a green digestion method which only used H2O2 as an oxidant and high temperature and pressure in the single reaction chamber system (SRC-UltraWave™) was applied for subsequent elemental determination by inductively coupled plasma-based techniques. Milk powder was chosen to demonstrate the feasibility and advantages of the proposed method. Samples masses up to 500mg were efficiently digested, and the determination of Ca, Fe, K, Mg and Na was performed by inductively coupled plasma optical emission spectrometry (ICP-OES), while trace elements (B, Ba, Cd, Cu, Mn, Mo, Pb, Sr and Zn) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Residual carbon (RC) lower than 918mgL(-1) of C was obtained for digests which contributed to minimizing interferences in determination by ICP-OES and ICP-MS. Accuracy was evaluated using certified reference materials NIST 1549 (non-fat milk powder certified reference material) and NIST 8435 (whole milk powder reference material). The results obtained by the proposed method were in agreement with the certified reference values (t-test, 95% confidence level). In addition, no significant difference was observed between results obtained by the proposed method and conventional wet digestion using concentrated HNO3. As digestion was performed without using any kind of acid, the characteristics of final digests were in agreement with green chemistry principles when compared to digests obtained using conventional wet digestion method with concentrated HNO3. Additionally, H2O2 digests were more suitable for subsequent analysis by ICP-based techniques due to of water being the main product of organic matrix oxidation. The proposed method was suitable for quality control of major components and trace elements present in milk powder in consonance with green sample preparation. PMID:27260458

  15. Soil Flux Chamber Measurements with Five Species CRDS and New Realtime Chamber Flux Processor

    NASA Astrophysics Data System (ADS)

    Saad, N.; Alstad, K. P.; Arata, C.; Franz, P.

    2014-12-01

    Continuous soil flux chamber measurements remains a key tool for determining production and sequestration of direct and indirect greenhouse gases. The Picarro G2508 Cavity Ring-down Spectrometer has radically simplified soil flux studies by providing simultaneous measurements of five gases: CO2, CH4, N2O, NH3, and H2O, and by lending itself to field deployment. Successful use of the Picarro G2508 for continuous soil flux measurements in a variety of ecosystem types has already been demonstrated. Most recently, Picarro is developing a real-time processing software to simplify chamber measurements of soil flux with the G2508 CRDS. The new Realtime Chamber Flux Processor is designed to work with all chamber types and sizes, and provides real-time flux values of N2O, CO2 & CH4. The software features include chamber sequence table, flexible data tagging feature, ceiling concentration measurement shut-off parameter, user-defined run-time interval, temperature/pressure input for field monitoring and volumetric conversion, and manual flux measurement start/stop override. Realtime Chamber Flux Processor GUI interface is presented, and results from a variety of sampling designs are demonstrated to emphasize program flexibility and field capability.

  16. Cooling of rocket thrust chambers with liquid oxygen

    NASA Technical Reports Server (NTRS)

    Armstrong, Elizabeth S.; Schlumberger, Julie A.

    1990-01-01

    Rocket engines using high pressure liquid oxygen (LOX) and kerosene (RP-1) as the propellants have been considered for future launch vehicle propulsion. Generally, in regeneratively cooled engines, the fuel is used to cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability at high temperatures and pressures. Therefore, LOX is being considered as an alternative coolant. However, there has been concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot-gas side wall. To address this concern, an investigation was previously conducted with simulated fatigue cracks upstream of the thrust chamber throat. When these chambers were tested, an unexpected melting in the throat region developed which was not in line with the simulated fatigue cracks. The current experimental program was conducted in order to determine the cause for the failure in the earlier thrust chambers and to further investigate the effects of cracks in the thrust chamber liner upstream of the throat. The thrust chambers were tested at oxygen-to-fuel mixture ratios from 1.5 to 2.86 at a nominal chamber pressure of 8.6 MPa. As a result of the test series, the reason for the failure occurring in the earlier work was determined to be injector anomalies. The LOX leaking through the simulated fatigue cracks did not affect the integrity of the chambers.

  17. Cooling of rocket thrust chambers with liquid oxygen

    NASA Technical Reports Server (NTRS)

    Armstrong, Elizabeth S.; Schlumberger, Julie A.

    1990-01-01

    Rocket engines using high pressure liquid oxygen (LOX) and kerosene (RP-1) as the propellants have been considered for future launch vehicle propulsion. Generaly, in regeneratively cooled engines, thefuel is used to cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability at high temperatures and pressures. Therefore, LOX is being considered as an alternative coolant. However, there has been concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot-gas side wall. To address this concern, an investigation was previously conducted with simulated fatigue cracks upstream of the thrust chamber throat. When these chambers were tested, an unexpected melting in the throat region developed which was not in line with the simulated fatigue cracks. The current experimental program was conducted in order to determine the cause for the failure in the earlier thrust chambers and to further investigate the effects of cracks in the thrust chamber liner upstream of the throat. The thrust chambers were tested at oxygen-to-fuel mixture ratios from 1.5 to 2.86 at a nominal chamber pressure of 8.6 MPa. As a result of the test series, the reason for the failure occurring in the earlier work was determined to be injector anomalies. The LOX leaking through the simulated fatigue cracks did not affect the integrity of the chambers.

  18. Combustion interaction with radiation-cooled chambers

    NASA Technical Reports Server (NTRS)

    Rosenberg, S. D.; Jassowski, D. M.; Barlow, R.; Lucht, R.; Mccarty, K.

    1990-01-01

    Over 15 hours of thruster operation at temperatures between 1916 and 2246 C without failure or erosion has been demonstrated using iridium-coated rhenium chamber materials with nitrogen tetroxide/monomethylhydrazine propellants operating over a mixture ratio range of 1.60-2.05. Research is now under way to provide a basic understanding of the mechanisms which make high-temperature operation possible and to extend the capability to a wider range of conditions, including other propellant combinations and chamber materials. Techniques have been demonstrated for studying surface fracture phenomena. These include surface Raman and Auger for study of oxide formation, surface Raman and X-ray diffraction to determine the oxide phase, Auger to study oxide stoichiometry, and sputter Auger to study interdiffusion of alloy species.

  19. Diogene pictorial drift chamber

    SciTech Connect

    Gosset, J.

    1984-01-01

    A pictorial drift chamber, called DIOGENE, has been installed at Saturne in order to study central collisions of high energy heavy ions. It has been adapted from the JADE internal detector, with two major differences to be taken into account. First, the center-of-mass of these collisions is not identical to the laboratory reference frame. Second, the energy loss and the momentum ranges of the particles to be detected are different from the ones in JADE. It was also tried to keep the cost as small as possible, hence the choice of minimum size and minimum number of sensitive wires. Moreover the wire planes are shifted from the beam axis: this trick helps very much to quickly reject the bad tracks caused by the ambiguity of measuring drift distances (positive or negative) through times (always positive).

  20. Mush Column Magma Chambers

    NASA Astrophysics Data System (ADS)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  1. Determining aerodynamic conductance of spar chambers from energy balance measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aerodynamic conductance (gA) of SPAR chambers was determined from measurements of energy balance and canopy temperature over a peanut canopy. gA was calculated from the slope of sensible heat flux (H) versus canopy-to-air temperature difference. H and the canopy-to-air temperature were varied by...

  2. The fast Ice Nucleus chamber FINCH

    NASA Astrophysics Data System (ADS)

    Bundke, U.; Nillius, B.; Jaenicke, R.; Wetter, T.; Klein, H.; Bingemer, H.

    2008-11-01

    We present first results of our new developed Ice Nucleus (IN) counter FINCH from the sixth Cloud and Aerosol Characterization Experiment (CLACE 6) campaign at Jungfraujoch station, 3571 m asl. Measurements were made at the total and the ICE CVI inlet. Laboratory measurements of ice onset temperatures by FINCH are compared to those of the static diffusion chamber FRIDGE (FRankfurt Ice Deposition Freezing Experiment). Within the errors of both new instruments the results compare well to published data.

  3. Multi-chamber controllable heat pipe

    NASA Technical Reports Server (NTRS)

    Shlosinger, A. P. (Inventor)

    1970-01-01

    A temperature controllable heat pipe switching device is reported. It includes separate evaporating and condensing chambers interconnected by separate vapor flow and liquid return conduits. The vapor flow conduit can be opened or closed to the flow of vapor, whereas the liquid return conduit blocks vapor flow at all times. When the vapor flow path is open, the device has high thermal conductivity, and when the vapor flow path is blocked the device has low thermal conductivity.

  4. Compact Vapor Chamber Cools Critical Components

    NASA Technical Reports Server (NTRS)

    2015-01-01

    Advancements in the production of proton exchange membrane fuel cells have NASA considering their use as a power source for spacecraft and robots in future space missions. With SBIR funding from Glenn Research Center, Lancaster, Pennsylvania-based Thermacore Inc. developed strong, lightweight titanium vapor chambers to keep the fuel cells operating at optimum temperatures. The company is now selling the technology for cooling electronic components.

  5. Detecting dark matter with scintillating bubble chambers

    NASA Astrophysics Data System (ADS)

    Zhang, Jianjie; Dahl, C. Eric; Jin, Miaotianzi; Baxter, Daniel

    2016-03-01

    Threshold based direct WIMP dark matter detectors such as the superheated bubble chambers developed by the PICO experiment have demonstrated excellent electron-recoil and alpha discrimination, excellent scalability, ease of change of target fluid, and low cost. However, the nuclear-recoil like backgrounds have been a limiting factor in their dark matter sensitivity. We present a new type of detector, the scintillating bubble chamber, which reads out the scintillation pulse of the scattering events as well as the pressure, temperature, acoustic traces, and bubble images as a conventional bubble chamber does. The event energy provides additional handle to discriminate against the nuclear-recoil like backgrounds. Liquid xenon is chosen as the target fluid in our prototyping detector for its high scintillation yield and suitable vapor pressure which simplifies detector complexity. The detector can be used as an R&D tool to study the backgrounds present in the current PICO bubble chambers or as a prototype for standalone dark matter detectors in the future. Supported by DOE Grant DE-SC0012161.

  6. HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF PLENUM WITH ATTACHED DRAFT REGULATOR. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  7. An anechoic chamber facility for investigating aerodynamic noise

    NASA Technical Reports Server (NTRS)

    Massier, P. F.; Parthasarathy, S. P.

    1972-01-01

    The aerodynamic noise facility was designed to be used primarily for investigating the noise-generating mechanisms of high-temperature supersonic and subsonic jets. The facility consists of an anechoic chamber, an exhaust jet silencer, instrumentation equipment, and an air heater with associated fuel and cooling systems. Compressed air, when needed for jet noise studies, is provided by the wind tunnel compressor facility on a continuous basis. The chamber is 8.1 m long, 5.0 m wide, and 3.0 m high. Provisions have been made for allowing outside air to be drawn into the anechoic chamber in order to replenish the air that is entrained by the jet as it flows through the chamber. Also, openings are provided in the walls and in the ceiling for the purpose of acquiring optical measurements. Calibration of the chamber for noise reflections from the wall was accomplished in octave bands between 31.2 Hz and 32 kHz.

  8. Plant growth chamber based on space proven controlled environment technology

    SciTech Connect

    Ignatius, R.W.; Ignatius, M.H.; Imberti, H.J.

    1997-01-01

    Quantum Devices, Inc., in conjunction with Percival Scientific, Inc., and the Wisconsin Center for Space Automation and Robotics (WCSAR) have developed a controlled environment plant growth chamber for terrestrial agricultural and scientific applications. This chamber incorporates controlled environment technology used in the WCSAR ASTROCULTURE{trademark} flight unit for conducting plant research on the Space Shuttle. The new chamber, termed CERES 2010, features air humidity, temperature, and carbon dioxide control, an atmospheric contaminant removal unit, an LED lighting system, and a water and nutrient delivery system. The advanced environment control technology used in this chamber will increase the reliability and repeatability of environmental physiology data derived from plant experiments conducted in this chamber. {copyright} {ital 1997 American Institute of Physics.}

  9. Potassium Rankine cycle vapor chamber (heat pipe) radiator study

    NASA Technical Reports Server (NTRS)

    Gerrels, E. E.; Killen, R. E.

    1971-01-01

    A structurally integrated vapor chamber fin (heat pipe) radiator is defined and evaluated as a potential candidate for rejecting waste heat from the potassium Rankine cycle powerplant. Several vapor chamber fin geometries, using stainless steel construction, are evaluated and an optimum is selected. A comparison is made with an operationally equivalent conduction fin radiator. Both radiators employ NaK-78 in the primary coolant loop. In addition, the Vapor Chamber Fin (VCF) radiator utilizes sodium in the vapor chambers. Preliminary designs are developed for the conduction fin and VCF concepts. Performance tests on a single vapor chamber were conducted to verify the VCF design. A comparison shows the conduction fin radiator easier to fabricate, but heavier in weight, particularly as meteoroid protection requirements become more stringent. While the analysis was performed assuming the potassium Rankine cycle powerplant, the results are equally applicable to any system radiating heat to space in the 900 to 1400 F temperature range.

  10. Beam Window for Pressure Chambers

    NASA Technical Reports Server (NTRS)

    Bransford, J. W.; Austin, J. G., Jr.

    1985-01-01

    Window resists products of combustion experiments. Sodium chloride window seals over chamber pressures from 0.1 to 13.8 MPa while absorbing minimal energy from CO2 laser beam that passes through it into chamber. Window inexpensive and easily replacable.

  11. LRL 25-inch Bubble Chamber

    DOE R&D Accomplishments Database

    Alvarez, L. W.; Gow, J. D.; Barrera, F.; Eckman, G.; Shand, J.; Watt, R.; Norgren, D.; Hernandez, H. P.

    1964-07-08

    The recently completed 25-inch hydrogen bubble chamber combines excellent picture quality with a fast operating cycle. The chamber has a unique optical system and is designed to take several pictures each Bevatron pulse, in conjunction with the Bevatron rapid beam ejection system.

  12. Chamber Music: Skills and Teamwork.

    ERIC Educational Resources Information Center

    Villarrubia, Charles

    2000-01-01

    Focuses on the benefits of participating in chamber music ensembles, such as the development of a heightened level of awareness, and considers the role of the music educator/conductor. Provides tools and exercises that teachers can introduce to chamber music players to improve their rehearsals and performances. (CMK)

  13. Nondestructive Inspection Using Neutron for Regenerative Cooling Combustion Chamber

    NASA Astrophysics Data System (ADS)

    Masuoka, Tadashi; Sato, Masaki; Moriya, Shin-Ichi; Tsuchiya, Yoshinori; Suzuki, Hiroshi; Iikura, Hiroshi; Matsubayashi, Masatoshi

    The regenerative cooling combustion chamber of a liquid rocket engine is exposed to large temperature difference between the combustion gas and the coolant such as liquid hydrogen. It induces thermal stress, and strain is accumulated over cyclic firing tests in the chamber wall. To evaluate the strain and the deformation of chamber walls is important since the chamber life usually relates to such strain and deformation. The primary objective of the present study is to establish a method to obtain experimental data on strains and deformations for correlation with the numerical data. In this study, residual strains and radiographs of a combustion chamber were obtained by applying a neutron diffraction method and a neutron radiography. Furthermore, two-dimensional nonlinear finite element method (FEM) analyses were conducted to calculate the residual strain in the chamber wall. From data of strain measurements, the feasibility of a neutron diffraction method for a combustion chamber was shown because the data from a X-ray diffraction method and FEM analyses qualitatively corresponded with those from a neutron diffraction method. Concerning neutron radiography, a higher resolution was necessary to observe chamber wall deformation.

  14. Ion chamber based neutron detectors

    DOEpatents

    Derzon, Mark S; Galambos, Paul C; Renzi, Ronald F

    2014-12-16

    A neutron detector with monolithically integrated readout circuitry, including: a bonded semiconductor die; an ion chamber formed in the bonded semiconductor die; a first electrode and a second electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; and the readout circuitry which is electrically coupled to the first and second electrodes. The bonded semiconductor die includes an etched semiconductor substrate bonded to an active semiconductor substrate. The readout circuitry is formed in a portion of the active semiconductor substrate. The ion chamber has a substantially planar first surface on which the first electrode is formed and a substantially planar second surface, parallel to the first surface, on which the second electrode is formed. The distance between the first electrode and the second electrode may be equal to or less than the 50% attenuation length for neutrons in the neutron absorbing material filling the ion chamber.

  15. Proton beam monitor chamber calibration.

    PubMed

    Gomà, C; Lorentini, S; Meer, D; Safai, S

    2014-09-01

    The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences-of the order of 3%-were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth-i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers-rather than cylindrical chambers-for the reference dosimetry of pseudo-monoenergetic proton beams. PMID:25109620

  16. Autoignition Chamber for Remote Testing of Pyrotechnic Devices

    NASA Technical Reports Server (NTRS)

    Harrington, Maureen L.; Steward, Gerald R.; Dartez, Toby W.

    2009-01-01

    The autoignition chamber (AIC) performs by remotely heating pyrotechnic devices that can fit the inner diameter of the tube furnace. Two methods, a cold start or a hot start, can be used with this device in autoignition testing of pyrotechnics. A cold start means extending a pyrotechnic device into the cold autoignition chamber and then heating the device until autoignition occurs. A hot start means heating the autoignition chamber to a specified temperature, and then extending the device into a hot autoignition chamber until autoignition occurs. Personnel are remote from the chamber during the extension into the hot chamber. The autoignition chamber, a commercially produced tubular furnace, has a 230-V, single-phase, 60-Hz electrical supply, with a total power output of 2,400 W. It has a 6-in. (15.2-cm) inner diameter, a 12-in. (30.4-cm) outer diameter and a 12-in.- long (30.4-cm), single-zone, solid tubular furnace (element) capable of heating to temperatures up to 2,012 F (1,100 C) in air.

  17. Structurally compliant rocket engine combustion chamber: Experimental and analytical validation

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert S.; Arya, Vinod K.; Kazaroff, John M.; Halford, Gary R.

    1994-01-01

    A new, structurally compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations.

  18. Vapor chambers for an atmospheric cloud physics laboratory

    NASA Technical Reports Server (NTRS)

    Fleischman, G. L.; Scollon, T. R., Jr.; Loose, J. D.

    1980-01-01

    The methanol/stainless steel vapor chambers (flat-plate heat pipes) discussed in this paper were developed for use in spaceborne atmospheric cloud chambers. This application imposed stringent thermal and mechanical requirements on the design. Flatness, low thermal mass, vibration, and structural integrity requirements were achieved in addition to precision temperature uniformity and thermal transport. Heat transfer coefficients on the order of 0.34 to 0.40 W/sq cm -C were measured. The vapor chambers are capable of transporting 170 W-cm per cm of width in either the axial or side-to-side direction.

  19. Environmental chamber studies of atmospheric reactivities of volatile organic compounds: Effects of varying chamber and light source

    SciTech Connect

    Carter, W.; Luo, D.; Malkina, I.; Pierce, J.

    1995-05-01

    Photochemical oxidant models are essential tools for assessing effects of emissions changes on ground-level ozone formation. Such models are needed for predicting the ozone impacts of increased alternative fuel use. The gas-phase photochemical mechanism is an important component of these models because ozone is not emitted directly, but is formed from the gas-phase photochemical reactions of the emitted volatile organic compounds (VOCs) and oxides of nitrogen (NO{sub x}) in air. The chemistry of ground level ozone formation is complex; hundreds of types of VOCs being emitted into the atmosphere, and most of their atmospheric reactions are not completely understood. Because of this, no chemical model can be relied upon to give even approximately accurate predictions unless it has been evaluated by comparing its predictions with experimental data. Therefore an experimental and modeling study was conducted to assess how chemical mechanism evaluations using environmental chamber data are affected by the light source and other chamber characteristics. Xenon arc lights appear to give the best artificial representation of sunlight currently available, and experiments were conducted in a new Teflon chamber constructed using such a light source. Experiments were also conducted in an outdoor Teflon Chamber using new procedures to improve the light characterization, and in Teflon chambers using blacklights. These results, and results of previous runs other chambers, were compared with model predictions using an updated detailed chemical mechanism. The magnitude of the chamber radical source assumed when modeling the previous runs were found to be too high; this has implications in previous mechanism evaluations. Temperature dependencies of chamber effects can explain temperature dependencies in chamber experiments when Ta-300{degree}K, but not at temperatures below that.

  20. Diesel exhaust cleaner with burner vortex chamber

    SciTech Connect

    Riddel, J.W.

    1983-05-17

    A diesel engine exhaust cleaner and burner system includes at least one exhaust cleaner member with a filter positioned therein to effect removal of particulates from a stream of exhaust gas delivered thereto via an inlet manifold. A fuel burner supplied with fuel by a fuel nozzle is operatively associated with the inlet manifold to supply the necessary heat to effect incineration of particulates collected on the filter. A cyclone duct providing a vortex chamber therein is operatively positioned downstream of the fuel nozzle and is supplied with sufficient air so as to effect both the complete combustion of the fuel and the controlled incineration of the particulates by increasing the residence time of the fuel in the reaction region within the vortex chamber and also effecting a more uniform distribution of the heat of combustion across the inlet face of the filter for the uniform heating of the particulates thereon to their combustion temperature.

  1. Starting a High School Chamber Music Group.

    ERIC Educational Resources Information Center

    Rutkowski, Joseph

    2000-01-01

    Presents ideas on how to begin a chamber music ensemble. Discusses how to find time to accomplish chamber music playing in and around the school day. Presents short descriptions of chamber music that can be used with ensembles. Includes chamber music resources and additional chamber works. (CMK)

  2. Computational fluid dynamic (CFD) investigation of thermal uniformity in a thermal cycling based calibration chamber for MEMS

    NASA Astrophysics Data System (ADS)

    Gui, Xulong; Luo, Xiaobing; Wang, Xiaoping; Liu, Sheng

    2015-12-01

    Micro-electrical-mechanical system (MEMS) has become important for many industries such as automotive, home appliance, portable electronics, especially with the emergence of Internet of Things. Volume testing with temperature compensation has been essential in order to provide MEMS based sensors with repeatability, consistency, reliability, and durability, but low cost. Particularly, in the temperature calibration test, temperature uniformity of thermal cycling based calibration chamber becomes more important for obtaining precision sensors, as each sensor is different before the calibration. When sensor samples are loaded into the chamber, we usually open the door of the chamber, then place fixtures into chamber and mount the samples on the fixtures. These operations may affect temperature uniformity in the chamber. In order to study the influencing factors of sample-loading on the temperature uniformity in the chamber during calibration testing, numerical simulation work was conducted first. Temperature field and flow field were simulated in empty chamber, chamber with open door, chamber with samples, and chamber with fixtures, respectively. By simulation, it was found that opening chamber door, sample size and number of fixture layers all have effects on flow field and temperature field. By experimental validation, it was found that the measured temperature value was consistent with the simulated temperature value.

  3. Neutron detection via bubble chambers.

    PubMed

    Jordan, D V; Ely, J H; Peurrung, A J; Bond, L J; Collar, J I; Flake, M; Knopf, M A; Pitts, W K; Shaver, M; Sonnenschein, A; Smart, J E; Todd, L C

    2005-01-01

    Research investigating the application of pressure-cycled bubble chambers to fast neutron detection is described. Experiments with a Halon-filled chamber showed clear sensitivity to an AmBe neutron source and insensitivity to a (137)Cs gamma source. Bubble formation was documented using high-speed photography, and a ceramic piezo-electric transducer element registered the acoustic signature of bubble formation. In a second set of experiments, the bubble nucleation response of a Freon-134a chamber to an AmBe neutron source was documented with high-speed photography. PMID:16005238

  4. The multigap resistive plate chamber

    SciTech Connect

    Zeballos, E. Cerron; Crotty, I.; Hatzifotiadou, D.; Valverde, J. Lamas; Neupane, S.; Williams, M. C. S.; Zichichi, A.

    2015-02-03

    The paper describes the multigap resistive plate chamber (RPC). This is a variant of the wide gap RPC. However it has much improved time resolution, while keeping all the other advantages of the wide gap RPC design.

  5. Perspectives on anechoic chamber qualification

    NASA Astrophysics Data System (ADS)

    Cunefare, Kenneth A.; Biesel, Van B.

    2002-11-01

    The qualification of a new anechoic chamber requires demonstration that the chamber produces a free-field environment within some tolerance bounds and over some acceptable volume. At the most basic level, qualification requires measurement of sound levels at increasing distances from a test source, and then comparing the levels to a theoretical free-field decay. While simple in concept, the actual performance of a qualification test is problematic in implementation, with troublesome issues relevant to the nature of the sound source, test signal (broadband or pure tone), spatial resolution of measurements (e.g., measurements at discrete locations or spatially continuous), and comparison of the data to a theoretical decay. This presentation will provide a brief historical perspective on chamber qualification and review current practice. It will demonstrate the inadequacy of broadband noise and widely spaced discrete measurements for qualification purposes. It will demonstrate that pure tone signals and spatially continuous measurements provide a rigorous test of a chambers performance.

  6. Drift and proportional tracking chambers

    NASA Astrophysics Data System (ADS)

    Jaros, J. A.

    1980-11-01

    The many techniques exploited in constructing tracking chambers, particle detectors which measure the trajectories and momenta of charged particles, are discussed. In high energy interactions, the final states are dominated by closely collimated jets of high multiplicity, requiring good track-pair resolution in the tracking chamber. High energy particles deflect very little in limited magnetic field volumes, necessitating good spatial resolution for accurate momentum measurements. The colliding beam technique requires a device easily adapted to full solid angle coverage, and the high event rates expected in some of these machines put a premium on good time resolution. Finally, the production and subsequent decays of the tau, charmed and beautiful mesons provide multiple vertex topologies. To reconstruct these vertices reliably requires improvements in spatial resolution and track pair resolution. The proportional counter and its descendant, the drift chamber, are considered as tracking chambers. The physics of this device are discussed in order to understand its performance limitations and promises.

  7. Cyclically controlled welding purge chamber

    NASA Technical Reports Server (NTRS)

    Gallagher, Robert L. (Inventor)

    1996-01-01

    An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

  8. IRIS Leaves Thermal Vacuum Chamber

    NASA Video Gallery

    This video shows the transportation of the IRIS observatory from the thermal vacuum chamber back to the clean tent for final testing and preparations for delivery to the launch site at Vandenberg A...

  9. Light diffusing fiber optic chamber

    DOEpatents

    Maitland, Duncan J.

    2002-01-01

    A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

  10. Convective Regimes in Crystallizing Basaltic Magma Chambers

    NASA Astrophysics Data System (ADS)

    Gilbert, A. J.; Neufeld, J. A.; Holness, M. B.

    2015-12-01

    disaggregated crystal mush. Such disaggregation may be caused by magma chamber replenishment, depending on the relative densities and temperatures of the resident and replenishing magma. If the new magma increases the Rayleigh number of either the bulk fluid or the fluid in the mushy layer, the resultant increased convective vigour may disaggregate the crystal pile.