Hugoniot measurements in vanadium using the LNL two-stage light-gas gun

International Nuclear Information System (INIS)

Gathers, G.R.; Mitchell, A.C.; Holmes, N.C.

1983-01-01

Hugoniot measurements on vanadium have been made using the LLNL two-stage light-gas gun. The direct collision method with electrical pins and a tantalum flyer accelerated to 6.28 km/s was used. Alt'shuler, et. al., have reported Hugoniot measurements in vanadium using explosives and the impedance match method. They reported a kink in the U/sub s/ - U/sub p/ relationship at 183 GPa, and attribute it to electronic transitions. The upper portion of their curve is based on a single point at 339 GPa. The present work was performed to further investigate the equation-of-state in the high-pressure range

Thermodynamic analysis of single-stage and multi-stage adsorption refrigeration cycles with activated carbon–ammonia working pair

International Nuclear Information System (INIS)

Xu, S.Z.; Wang, L.W.; Wang, R.Z.

2016-01-01

Highlights: • Activated carbon–ammonia multi-stage adsorption refrigerator was analyzed. • COP, exergetic efficiency and entropy production of cycles were calculated. • Single-stage cycle usually has the advantages of simple structure and high COP. • Multi-stage cycles adapt to critical conditions better than single-stage cycle. • Boundary conditions for choosing optimal cycle were summarized as tables. - Abstract: Activated carbon–ammonia multi-stage adsorption refrigeration cycle was analyzed in this article, which realized deep-freezing for evaporating temperature under −18 °C with heating source temperature much lower than 100 °C. Cycle mathematical models for single, two and three-stage cycles were established on the basis of thorough thermodynamic analysis. According to simulation results of thermodynamic evaluation indicators such as COP (coefficient of performance), exergetic efficiency and cycle entropy production, multi-stage cycle adapts to high condensing temperature, low evaporating temperature and low heating source temperature well. Proposed cycle with selected working pair can theoretically work under very severe conditions, such as −25 °C evaporating temperature, 40 °C condensing temperature, and 70 °C heating source temperature, but under these working conditions it has the drawback of low cycle adsorption quantity. It was found that both COP and exergetic efficiency are of great reference value in the choice of cycle, whereas entropy production is not so useful for cycle stage selection. Finally, the application boundary conditions of single-stage, two-stage, and three-stage cycles were summarized as tables according to the simulation results, which provides reference for choosing optimal cycle under different conditions.

Delayed Single Stage Perineal Posterior Urethroplasty

International Nuclear Information System (INIS)

Ali, S.; Shahnawaz; Shahzad, I.; Baloch, M. U.

2015-01-01

Objective: To determine the delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture/distraction defect. Study Design: Descriptive case series. Place and Duration of Study: Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from January 2009 to December 2011. Methodology: Patients were selected for delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture / distraction defect. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Results: Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patients age was 26.25 ± 7.9 years. On follow-up, 7 patients (23.3 percentage) experienced recurrent stricture during first 10 months. Five (16.6 percentage) patients were treated successfully with single direct visual internal urethrotomy. Two patients (6.6 percentage) had more than one direct visual internal urethrotomy and considered failed. Re-do perineal urethroplasty was eventually performed. The overall success rate was 93.3 percentage with permissive criteria allowing single direct visual internal urethrotomy and 76.6% with strict criteria allowing no more procedures postoperatively. Conclusion: Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures. (author)

Single conversion stage amplifier - SICAM

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.

2005-12-15

This Ph.D. thesis presents a thorough analysis of the so called SICAM - SIngle Converter stage AMplifier approach to building direct energy conversion audio power amplifiers. The mainstream approach for building isolated audio power amplifiers today consists of isolated DC power supply and Class D amplifier, which essentially represents a two stage solution, where each of the components can be viewed as separate and independent part. The proposed SICAM solution strives for direct energy conversion from the mains to the audio output, by dedicating the operation of the components one to another and integrating their functions, so that the final audio power amplifier represents a single-stage topology with higher efficiency, lower volume, less board space, lower component count and subsequently lower cost. The SICAM approach is both applicable to non-isolated and isolated audio power amplifiers, but the problems encountered in these two cases are different. Non-isolated SICAM solutions are intended for both AC mains-connected and battery-powered devices. In non-isolated mains-connected SICAMs the main idea is to simplify the power supply or even provide integrated power factor correction (PFC) functions, while still maintaining low component stress and good audio performance by generally decreasing the input voltage level to the Class D audio power amplifier. On the other hand, non-isolated battery-powered SICAMs have to cope with the ever changing battery voltage and provide output voltage levels which are both lower and higher than the battery voltage, while still being simple and single-stage energy conversion solutions. In isolated SICAMs the isolation transformer adjusts the voltage level on the secondary side to the desired level, so the main challenges here are decreasing the size of the magnetic core and reducing the number and size of bulky reactive components as much as possible. The main focus of this thesis is directed towards the isolated SICAMs and

New results for single stage low energy carbon AMS

International Nuclear Information System (INIS)

Klody, G.M.; Schroeder, J.B.; Norton, G.A.; Loger, R.L.; Kitchen, R.L.; Sundquist, M.L.

2005-01-01

A new configuration of the NEC single stage, low energy carbon AMS system (U.S. Patent 6,815,666 B2) has been built and tested. The injector includes two 40-sample ion sources, electrostatic and magnetic analysis, and fast sequential injection. The gas stripper, analyzing magnet, electrostatic analyzer, and detector are on an open air 250 kV deck. Both 12 C and 13 C currents are measured on the deck after the stripper, and an SSB detector is used for 14 C counting. Injected 12 C and mass 13 ( 13 C and 12 CH) currents are also measured. Automated controls follow a user-specified run list for unattended operation. Initial test results show precision for 14 C/ 12 C ratios of better than 5 per mil, and backgrounds for unprocessed graphite of less than 0.005 x modern. We will report final results for precision, background, and throughput and discuss related design features

Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage Reactor

Energy Technology Data Exchange (ETDEWEB)

Mahesh Iyer; Himanshu Gupta; Danny Wong; Liang-Shih Fan

2005-09-30

Hydrogen production from coal gasification can be enhanced by driving the equilibrium limited Water Gas Shift reaction forward by incessantly removing the CO{sub 2} by-product via the carbonation of calcium oxide. This project aims at using the OSU patented high-reactivity mesoporous precipitated calcium carbonate sorbent for removing the CO{sub 2} product. Preliminary experiments demonstrate the show the superior performance of the PCC sorbent over other naturally occurring calcium sorbents. Gas composition analyses show the formation of 100% pure hydrogen. Novel calcination techniques could lead to smaller reactor footprint and single-stage reactors that can achieve maximum theoretical H{sub 2} production for multicyclic applications. Sub-atmospheric calcination studies reveal the effect of vacuum level, diluent gas flow rate, thermal properties of the diluent gas and the sorbent loading on the calcination kinetics which play an important role on the sorbent morphology. Steam, which can be easily separated from CO{sub 2}, is envisioned to be a potential diluent gas due to its enhanced thermal properties. Steam calcination studies at 700-850 C reveal improved sorbent morphology over regular nitrogen calcination. A mixture of 80% steam and 20% CO{sub 2} at ambient pressure was used to calcine the spent sorbent at 820 C thus lowering the calcination temperature. Regeneration of calcium sulfide to calcium carbonate was achieved by carbonating the calcium sulfide slurry by bubbling CO{sub 2} gas at room temperature.

Single-stage-to-orbit versus two-stage-two-orbit: A cost perspective

Science.gov (United States)

Hamaker, Joseph W.

1996-03-01

This paper considers the possible life-cycle costs of single-stage-to-orbit (SSTO) and two-stage-to-orbit (TSTO) reusable launch vehicles (RLV's). The analysis parametrically addresses the issue such that the preferred economic choice comes down to the relative complexity of the TSTO compared to the SSTO. The analysis defines the boundary complexity conditions at which the two configurations have equal life-cycle costs, and finally, makes a case for the economic preference of SSTO over TSTO.

Single stage reconstruction of complex anterior urethral strictures

Directory of Open Access Journals (Sweden)

Deepak Dubey

2001-01-01

Full Text Available Purpose: Single stage reconstruction of long, com-plex urethral strictures is technically demanding and may require the use of more than one tissue transfer technique. We describe our experience in the manage-ment of such strictures with a variety of urethroplasty techniques. Materials and Methods: Between 1989 and 1999, 25 men (mean age 38.5 years underwent single stage re-construction of panurethral, multiple segment or focally dense strictures [mean length 11.2 cm (range 8-17 cm]. 8 patients had combined substitution urethroplasty with a circumpenile fasciocutaneous flap and a free graft of bladder/buccal mucosa or tunica vaginalis . flap. In 10 patients a single tissue transfer technique was used. 3 patients underwent an augmented roof/floor strip ure-throplasty with a penile skin flap. 4 patients with multi-ple segment strictures (separate pendulous and bulbar underwent distal onlay flap and proximal anastomotic urethroplasty. Results: The median ,follow-up was 46.5 months (range 6-88 months. The mean postoperative flow rate improved to 22.5 ml/sec. 2 patients developed fistulae requiring repair. Recurrent stricture developed in 5 (20.8% patients, of which 2 were managed with visual internal urethrotomy, 2 with anastomotic urethroplasty and 1 with a two-stage procedure. Pseudodiverticulum and post-void dribbling were seen in 6 (25% patients. Conclusions: Successful outcome of single stage re-construction of long complex strictures can be achieved with a combination of various tissue transfer methods. The urologist who has a thorough knowledge of penile skin and urethral vascular anatomy and a wide array of substitution techniques in his armamentarium can un-dertake approach to such strictures.

A Gas-Spring-Loaded X-Y-Z Stage System for X-ray Microdiffraction Sample Manipulation

International Nuclear Information System (INIS)

Shu Deming; Cai Zhonghou; Lai, Barry

2007-01-01

We have designed and constructed a gas-spring-loaded x-y-z stage system for x-ray microdiffraction sample manipulation at the Advanced Photon Source XOR 2-ID-D station. The stage system includes three DC-motor-driven linear stages and a gas-spring-based heavy preloading structure, which provides antigravity forces to ensure that the stage system keeps high-positioning performance under variable goniometer orientation. Microdiffraction experiments with this new stage system showed significant sample manipulation performance improvement

Comparative assessment of single-stage and two-stage anaerobic digestion for the treatment of thin stillage.

Science.gov (United States)

Nasr, Noha; Elbeshbishy, Elsayed; Hafez, Hisham; Nakhla, George; El Naggar, M Hesham

2012-05-01

A comparative evaluation of single-stage and two-stage anaerobic digestion processes for biomethane and biohydrogen production using thin stillage was performed to assess the impact of separating the acidogenic and methanogenic stages on anaerobic digestion. Thin stillage, the main by-product from ethanol production, was characterized by high total chemical oxygen demand (TCOD) of 122 g/L and total volatile fatty acids (TVFAs) of 12 g/L. A maximum methane yield of 0.33 L CH(4)/gCOD(added) (STP) was achieved in the two-stage process while a single-stage process achieved a maximum yield of only 0.26 L CH(4)/gCOD(added) (STP). The separation of acidification stage increased the TVFAs to TCOD ratio from 10% in the raw thin stillage to 54% due to the conversion of carbohydrates into hydrogen and VFAs. Comparison of the two processes based on energy outcome revealed that an increase of 18.5% in the total energy yield was achieved using two-stage anaerobic digestion. Copyright © 2012 Elsevier Ltd. All rights reserved.

Plasma gasification of refuse derived fuel in a single-stage system using different gasifying agents.

Science.gov (United States)

Agon, N; Hrabovský, M; Chumak, O; Hlína, M; Kopecký, V; Masláni, A; Bosmans, A; Helsen, L; Skoblja, S; Van Oost, G; Vierendeels, J

2016-01-01

The renewable evolution in the energy industry and the depletion of natural resources are putting pressure on the waste industry to shift towards flexible treatment technologies with efficient materials and/or energy recovery. In this context, a thermochemical conversion method of recent interest is plasma gasification, which is capable of producing syngas from a wide variety of waste streams. The produced syngas can be valorized for both energetic (heat and/or electricity) and chemical (ammonia, hydrogen or liquid hydrocarbons) end-purposes. This paper evaluates the performance of experiments on a single-stage plasma gasification system for the treatment of refuse-derived fuel (RDF) from excavated waste. A comparative analysis of the syngas characteristics and process yields was done for seven cases with different types of gasifying agents (CO2+O2, H2O, CO2+H2O and O2+H2O). The syngas compositions were compared to the thermodynamic equilibrium compositions and the performance of the single-stage plasma gasification of RDF was compared to that of similar experiments with biomass and to the performance of a two-stage plasma gasification process with RDF. The temperature range of the experiment was from 1400 to 1600 K and for all cases, a medium calorific value syngas was produced with lower heating values up to 10.9 MJ/Nm(3), low levels of tar, high levels of CO and H2 and which composition was in good agreement to the equilibrium composition. The carbon conversion efficiency ranged from 80% to 100% and maximum cold gas efficiency and mechanical gasification efficiency of respectively 56% and 95%, were registered. Overall, the treatment of RDF proved to be less performant than that of biomass in the same system. Compared to a two-stage plasma gasification system, the produced syngas from the single-stage reactor showed more favourable characteristics, while the recovery of the solid residue as a vitrified slag is an advantage of the two-stage set-up. Copyright �

design, construction and measured performance of a single-stage

African Journals Online (AJOL)

2012-11-03

Nov 3, 2012 ... Abstract. The design philosophy, construction and measured performances of a single stage, single entry centrifugal pump .... the tachometer spindle to be held against a recess in the motor shaft. The constructed centrifugal ...

Efficacy of single-stage and two-stage Fowler–Stephens laparoscopic orchidopexy in the treatment of intraabdominal high testis

Directory of Open Access Journals (Sweden)

Chang-Yuan Wang

2017-11-01

Conclusion: In the case of testis with good collateral circulation, single-stage F-S laparoscopic orchidopexy had the same safety and efficacy as the two-stage F-S procedure. Surgical options should be based on comprehensive consideration of intraoperative testicular location, testicular ischemia test, and collateral circumstances surrounding the testes. Under the appropriate conditions, we propose single-stage F-S laparoscopic orchidopexy be preferred. It may be appropriate to avoid unnecessary application of the two-stage procedure that has a higher cost and causes more pain for patients.

Staged fracturing of horizontal shale gas wells with temporary plugging by sand filling

Directory of Open Access Journals (Sweden)

Xing Liang

2017-03-01

Full Text Available Due to downhole complexities, shale-gas horizontal well fracturing in the Sichuan Basin suffered from casing deformation and failure to apply the technique of cable-conveyed perforation bridge plug. In view of these problems, a new technique of staged volume fracturing with temporary plugging by sand filling is employed. Based on theoretical analyses and field tests, a design of optimized parameters of coiled tubing-conveyed multi-cluster sand-blasting perforation and temporary plugging by sand filling was proposed. It was applied in the horizontal Well ZJ-1 in which casing deformation occurred. The following results are achieved in field operations. First, this technique enables selective staged fracturing in horizontal sections. Second, this technique can realize massive staged fracturing credibly without mechanical plugging, with the operating efficiency equivalent to the conventional bridge plug staged fracturing. Third, full-hole is preserved after fracturing, thus it is possible to directly conduct an open flow test without time consumption of a wiper trip. The staged volume fracturing with temporary plugging by sand filling facilitated the 14-stage fracturing in Well ZJ-1, with similar SRV to that achieved by conventional bridge plug staged fracturing and higher gas yield than neighboring wells on the same well pad. Thus, a new and effective technique is presented in multi-cluster staged volume fracturing of shale gas horizontal wells.

85,000-GPM, single-stage, single-suction LMFBR intermediate centrifugal pump

International Nuclear Information System (INIS)

Fair, C.E.; Cook, M.E.; Huber, K.A.; Rohde, R.

1983-01-01

The mechanical and hydraulic design features of the 85,000-gpm, single-stage, single-suction pump test article, which is designed to circulate liquid-sodium coolant in the intermediate heat-transport system of a Large-Scale Liquid Metal Fast Breeder Reactor (LS-LMFBR), are described. The design and analytical considerations used to satisfy the pump performance and operability requirements are presented. The validation of pump hydraulic performance using a hydraulic scale-model pump is discussed, as is the featute test for the mechanical-shaft seal system

Methodology of theory of stage-by-stage long-term preparation of sportsmen in single combats

Directory of Open Access Journals (Sweden)

Arziutov G.

2010-04-01

Full Text Available Results over of researches are brought on methodology of theory of stage-by-stage preparation of sportsmen in single combats. The structuralness of theory lies in possibility simple verifications of its substantive provisions, principles and laws. Development of methodology enables to begin creation of map of trainer on the stages of long-term preparation. Laws, conformities to law, principles and rules, must be collected in a map. A map enables the trainers of reserve sport to use its content during all stages of preparation of sportsman.

Single-session versus staged procedures for elective multivessel percutaneous coronary intervention.

Science.gov (United States)

Toyota, Toshiaki; Morimoto, Takeshi; Shiomi, Hiroki; Yamaji, Kyohei; Ando, Kenji; Ono, Koh; Shizuta, Satoshi; Saito, Naritatsu; Kato, Takao; Kaji, Shuichiro; Furukawa, Yutaka; Nakagawa, Yoshihisa; Kadota, Kazushige; Horie, Minoru; Kimura, Takeshi

2018-06-01

To clarify the effect of single-session multivessel percutaneous coronary intervention (PCI) strategy relative to the staged multivessel strategy on clinical outcomes in patients with stable coronary artery disease (CAD) or non-ST-elevation acute coronary syndrome. In the Coronary REvascularisation Demonstrating Outcome Study in Kyoto PCI/coronary artery bypass grafting registry cohort-2, there were 2018 patients who underwent elective multivessel PCI. Primary outcome measure was composite of all-cause death, myocardial infarction and stroke at 5-year follow-up. Single-session multivessel PCI and staged multivessel PCI were performed in 707 patients (35.0%) and 1311 patients (65.0%), respectively. The cumulative 5-year incidence of and adjusted risk for the primary outcome measure were not significantly different between the single-session and staged groups (26.7% vs 23.0%, p=0.45; HR 0.91, 95% CI 0.72 to 1.16, p=0.47). The 30-day incidence of all-cause death was significantly higher in the single-session group than in the staged group (1.1% vs 0.2%, p=0.009). However, the causes of death in 11 patients who died within 30 days were generally not related to the procedural complications, but related to the serious clinical status before PCI. For the subgroup analyses including age, gender, extent of CAD, severe chronic kidney disease and heart failure, there was no significant interaction between the subgroup factors and the effect of the single-session strategy relative to the staged strategy for the primary outcome measure. The single-session multivessel PCI strategy was associated with at least comparable 5-year clinical outcomes compared with the staged multivessel PCI, although the prevalence of the single-session strategy was low in the present study. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Gas retention and release behavior in Hanford single-shell waste tanks

International Nuclear Information System (INIS)

Stewart, C.W.; Brewster, M.E.; Gauglitz, P.A.; Mahoney, L.A.; Meyer, P.A.; Recknagle, K.P.; Reid, H.C.

1996-12-01

This report describes the current understanding of flammable gas retention and release in Hanford single-shell waste tanks based on theory, experimental results, and observations of tank behavior. The single-shell tanks likely to pose a flammable gas hazard are listed and described, and photographs of core extrusions and the waste surface are included. The credible mechanisms for significant flammable gas releases are described, and release volumes and rates are quantified as much as possible. The only mechanism demonstrably capable of producing large (∼100 m 3 ) spontaneous gas releases is the buoyant displacement, which occurs only in tanks with a relatively deep layer of supernatant liquid. Only the double-shell tanks currently satisfy this condition. All release mechanisms believed plausible in single-shell tanks have been investigated, and none have the potential for large spontaneous gas releases. Only small spontaneous gas releases of several cubic meters are likely by these mechanisms. The reasons several other postulated gas release mechanisms are implausible or incredible are also given

Comparing a single-stage geocoding method to a multi-stage geocoding method: how much and where do they disagree?

Directory of Open Access Journals (Sweden)

Rice Kenneth

2007-03-01

Full Text Available Abstract Background Geocoding methods vary among spatial epidemiology studies. Errors in the geocoding process and differential match rates may reduce study validity. We compared two geocoding methods using 8,157 Washington State addresses. The multi-stage geocoding method implemented by the state health department used a sequence of local and national reference files. The single-stage method used a single national reference file. For each address geocoded by both methods, we measured the distance between the locations assigned by each method. Area-level characteristics were collected from census data, and modeled as predictors of the discordance between geocoded address coordinates. Results The multi-stage method had a higher match rate than the single-stage method: 99% versus 95%. Of 7,686 addresses were geocoded by both methods, 96% were geocoded to the same census tract by both methods and 98% were geocoded to locations within 1 km of each other by the two methods. The distance between geocoded coordinates for the same address was higher in sparsely populated and low poverty areas, and counties with local reference files. Conclusion The multi-stage geocoding method had a higher match rate than the single-stage method. An examination of differences in the location assigned to the same address suggested that study results may be most sensitive to the choice of geocoding method in sparsely populated or low-poverty areas.

Two-stage hydroprocessing of synthetic crude gas oil

Energy Technology Data Exchange (ETDEWEB)

Mahay, A.; Chmielowiec, J.; Fisher, I.P.; Monnier, J. (Petro-Canada Products, Missisauga, ON (Canada). Research and Development Centre)

1992-02-01

The hydrocracking of synthetic crude gas oils (SGO), which are commercially produced from Canadian oil sands, is strongly inhibited by nitrogen-containing species. To alleviate the pronounced effect of these nitrogenous compounds, SGO was hydrotreated at severe conditions prior to hydrocracking to reduce its N content from 1665 to about 390 ppm (by weight). Hydrocracking was then performed using a commercial nickel-tungsten catalyst supported on silica-alumina. Two-stage hydroprocessing of SGO was assessed in terms of product yields and quality. As expected, higher gas oil conversion were achieved mostly from an increase in naphtha yield. The middle distillate product quality was also clearly improved as the diesel fuel cetane number increased by 13%. Diesel engine tests indicated that particulate emissions in exhaust gases were lowered by 20%. Finally, pseudo first-order kinetic equations were derived for the overall conversion of the major gas oil components. 17 refs., 2 figs., 8 tabs.

Methods for Gas Sensing with Single-Walled Carbon Nanotubes

Science.gov (United States)

Kaul, Anupama B. (Inventor)

2013-01-01

Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

Single-stage Acetabular Revision During Two-stage THA Revision for Infection is Effective in Selected Patients.

Science.gov (United States)

Fink, Bernd; Schlumberger, Michael; Oremek, Damian

2017-08-01

The treatment of periprosthetic infections of hip arthroplasties typically involves use of either a single- or two-stage (with implantation of a temporary spacer) revision surgery. In patients with severe acetabular bone deficiencies, either already present or after component removal, spacers cannot be safely implanted. In such hips where it is impossible to use spacers and yet a two-stage revision of the prosthetic stem is recommended, we have combined a two-stage revision of the stem with a single revision of the cup. To our knowledge, this approach has not been reported before. (1) What proportion of patients treated with single-stage acetabular reconstruction as part of a two-stage revision for an infected THA remain free from infection at 2 or more years? (2) What are the Harris hip scores after the first stage and at 2 years or more after the definitive reimplantation? Between June 2009 and June 2014, we treated all patients undergoing surgical treatment for an infected THA using a single-stage acetabular revision as part of a two-stage THA exchange if the acetabular defect classification was Paprosky Types 2B, 2C, 3A, 3B, or pelvic discontinuity and a two-stage procedure was preferred for the femur. The procedure included removal of all components, joint débridement, definitive acetabular reconstruction (with a cage to bridge the defect, and a cemented socket), and a temporary cemented femoral component at the first stage; the second stage consisted of repeat joint and femoral débridement and exchange of the femoral component to a cementless device. During the period noted, 35 patients met those definitions and were treated with this approach. No patients were lost to followup before 2 years; mean followup was 42 months (range, 24-84 months). The clinical evaluation was performed with the Harris hip scores and resolution of infection was assessed by the absence of clinical signs of infection and a C-reactive protein level less than 10 mg/L. All

The AGT 101 advanced automotive gas turbine

Science.gov (United States)

Rackley, R. A.; Kidwell, J. R.

1982-01-01

A development program is described whose goal is the accumulation of the technology base needed by the U.S. automotive industry for the production of automotive gas turbine powertrains. Such gas turbine designs must exhibit reduced fuel consumption, a multi-fuel capability, and low exhaust emissions. The AGT101 powertrain described is a 74.6 kW, regenerated single-shaft gas turbine, operating at a maximum inlet temperature of 1644 K and coupled to a split differential gearbox and automatic overdrive transmission. The engine's single stage centrifugal compressor and single stage radial inflow turbine are mounted on a common shaft, and will operate at a maximum rotor speed of 100,000 rpm. All high temperature components, including the turbine rotor, are ceramic.

Investigation of Advanced Propellants to Enable Single Stage to Orbit Launch Vehicles

National Research Council Canada - National Science Library

Mossman, Jason

2006-01-01

Single-Stage-To-Orbit (SSTO) launch vehicles designs offer the promise of reduced complexity and cost compared to multi-stage vehicles, as only one stage need be developed, produced, and maintained...

Gas retention and release behavior in Hanford single-shell waste tanks

Energy Technology Data Exchange (ETDEWEB)

Stewart, C.W.; Brewster, M.E.; Gauglitz, P.A.; Mahoney, L.A.; Meyer, P.A.; Recknagle, K.P.; Reid, H.C.

1996-12-01

This report describes the current understanding of flammable gas retention and release in Hanford single-shell waste tanks based on theory, experimental results, and observations of tank behavior. The single-shell tanks likely to pose a flammable gas hazard are listed and described, and photographs of core extrusions and the waste surface are included. The credible mechanisms for significant flammable gas releases are described, and release volumes and rates are quantified as much as possible. The only mechanism demonstrably capable of producing large ({approximately}100 m{sup 3}) spontaneous gas releases is the buoyant displacement, which occurs only in tanks with a relatively deep layer of supernatant liquid. Only the double-shell tanks currently satisfy this condition. All release mechanisms believed plausible in single-shell tanks have been investigated, and none have the potential for large spontaneous gas releases. Only small spontaneous gas releases of several cubic meters are likely by these mechanisms. The reasons several other postulated gas release mechanisms are implausible or incredible are also given.

High efficiency 40 K single-stage Stirling-type pulse tube cryocooler

Science.gov (United States)

Wu, X. L.; Chen, L. B.; Pan, C. Z.; Cui, C.; Wang, J. J.; Zhou, Y.

2017-12-01

A high efficiency single-stage Stirling-type coaxial pulse tube cryocooler (SPTC) operating at around 40 K has been designed, built and tested. The double-inlet and the inertance tubes together with the gas reservoir were adopted as the phase shifters. Under the conditions of 2.5 MPa charging pressure and 30 Hz operating frequency, the prototype has achieved a no-load temperature of 23.8 K with 330 W of electric input power at a rejection temperature of 279 K. When the input power increases to 400 W, it can achieve a cooling capacity of 4.7 W/40 K while rejecting heat at 279 K yielding an efficiency of 7.02% relative to Carnot. It achieves a cooling capacity of 5 W/40 K with an input power of 450 W. It takes 10 minutes for the SPTC to cool to its no-load temperature of 40 K from 295 K.

Numerical Simulation of single-stage axial fan operation under dusty flow conditions

Science.gov (United States)

Minkov, L. L.; Pikushchak, E. V.

2017-11-01

Assessment of the aerodynamic efficiency of the single-stage axial flow fan under dusty flow conditions based on a numerical simulation using the computational package Ansys-Fluent is proposed. The influence of dust volume fraction on the dependences of the air volume flow rate and the pressure drop on the rotational speed of rotor is demonstrated. Matching functions for formulas describing a pressure drop and volume flow rate in dependence on the rotor speed and dust content are obtained by numerical simulation for the single-stage axial fan. It is shown that the aerodynamic efficiency of the single-stage axial flow fan decreases exponentially with increasing volume content of dust in the air.

Promising results after single-stage reconstruction of the nipple and areola complex

DEFF Research Database (Denmark)

Børsen-Koch, Mikkel; Bille, Camilla; Thomsen, Jørn B

2013-01-01

Introduction: Reconstruction of the nipple-areola complex (NAC) traditionally marks the end of breast reconstruction. Several different surgical techniques have been described, but most are staged procedures. This paper describes a simple single-stage approach. Material and Methods: We used...... reconstruction was 43 min. (30-50 min.). Conclusion: This simple single-stage NAC reconstruction seems beneficial for both patient and surgeon as it seems to be associated with faster reconstruction and reduced procedure-related time without compromising the aesthetic outcome or the morbidity associated...

Single-stage Modified Duhamel procedure for Hirschsprung′s disease : Our experience

Directory of Open Access Journals (Sweden)

Paras R Kothari

2012-01-01

Full Text Available Introduction: Primary single-stage pull-through for Hirschsprung′s disease (HD has been reported to give comparable surgical outcomes to staged operations with less morbidity. Herein, we present our experience with single-stage Modified Duhamel procedure for management of HD. Patients and Methods: This was a review of 48 cases of HD who underwent single-stage Modified Duhamel procedure without a protective colostomy. Results: The age at surgery ranged from 6 months to 10 years (median - 9 months, mean - 2.3 years. The average weight of the child was 7.2 kg (range, 4.9-22 kg. 38 (79.2% patients had classical rectosigmoid HD, the rest being long segment HD (the proximal most level being the splenic flexure. The average duration of surgery was 175 minutes (range, 130-245 minutes. The average blood loss was 45 ml. The average hospital stay was 7.2 days (range: 6-10 days. The major postoperative complications (n=3 included postoperative adhesive intestinal obstruction, anastomotic leak and persistent constipation due to residual aganglionosis. Each required a re-exploration. Minor complications included surgical site infection (n=3 and post-operative enterocolitis (n=3, which were managed conservatively. Six patients had constipation for a limited period post-operatively. All patients have a satisfactory functional outcome and normal development and growth. Conclusions: For HD, we recommend that single-stage Modified Duhamel procedure should be the preferred approach in view of its low morbidity, satisfactory functional outcome and avoidance of stoma, multiple surgeries and economic benefit in view of decreased hospital stay.

Lot-sizing for a single-stage single-product production system with rework of perishable production defectives

NARCIS (Netherlands)

Teunter, R.; Flapper, S.D.P.

2003-01-01

We consider a single-stage single-product production system. Produced units may be non-defective, reworkable defective, or non-reworkable defective. The system switches between production and rework. After producing a fixed number (N) of units, all reworkable defective units are reworked. Reworkable

QUICKGUN: An algorithm for estimating the performance of two-stage light gas guns

International Nuclear Information System (INIS)

Milora, S.L.; Combs, S.K.; Gouge, M.J.; Kincaid, R.W.

1990-09-01

An approximate method is described for solving the equation of motion of a projectile accelerated by a two-stage light gas gun that uses high-pressure (<100-bar) gas from a storage reservoir to drive a piston to moderate speed (<400 m/s) for the purpose of compressing the low molecular weight propellant gas (hydrogen or helium) to high pressure (1000 to 10,000 bar) and temperature (1000 to 10,000 K). Zero-dimensional, adiabatic (isentropic) processes are used to describe the time dependence of the ideal gas thermodynamic properties of the storage reservoir and the first and second stages of the system. A one-dimensional model based on an approximate method of characteristics, or wave diagram analysis, for flow with friction (nonisentropic) is used to describe the nonsteady compressible flow processes in the launch tube. Linear approximations are used for the characteristic and fluid particle trajectories by averaging the values of the flow parameters at the breech and at the base of the projectile. An assumed functional form for the Mach number at the breech provides the necessary boundary condition. Results of the calculation are compared with data obtained from two-stage light gas gun experiments at Oak Ridge National Laboratory for solid deuterium and nylon projectiles with masses ranging from 10 to 35 mg and for projectile speeds between 1.6 and 4.5 km/s. The predicted and measured velocities generally agree to within 15%. 19 refs., 3 figs., 2 tabs

Single-stage versus two-stage anaerobic fluidized bed bioreactors in treating municipal wastewater: Performance, foulant characteristics, and microbial community.

Science.gov (United States)

Wu, Bing; Li, Yifei; Lim, Weikang; Lee, Shi Lin; Guo, Qiming; Fane, Anthony G; Liu, Yu

2017-03-01

This study examined the receptive performance, membrane foulant characteristics, and microbial community in the single-stage and two-stage anaerobic fluidized membrane bioreactor (AFMBR) treating settled raw municipal wastewater with the aims to explore fouling mechanisms and microbial community structure in both systems. Both AFMBRs exhibited comparable organic removal efficiency and membrane performances. In the single-stage AFMBR, less soluble organic substances were removed through biosorption by GAC and biodegradation than those in the two-stage AFMBR. Compared to the two-stage AFMBR, the formation of cake layer was the main cause of the observed membrane fouling in the single-stage AFMBR at the same employed flux. The accumulation rate of the biopolymers was linearly correlated with the membrane fouling rate. In the chemical-cleaned foulants, humic acid-like substances and silicon were identified as the predominant organic and inorganic fouants respectively. As such, the fluidized GAC particles might not be effective in removing these substances from the membrane surfaces. High-throughout pyrosequencing analysis further revealed that beta-Proteobacteria were predominant members in both AFMBRs, which contributed to the development of biofilms on the fluidized GAC and membrane surfaces. However, it was also noted that the abundance of the identified dominant in the membrane surface-associated biofilm seemed to be related to the permeate flux and reactor configuration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Single-stage anterior high sacrectomy for locally recurrent rectal cancer.

Science.gov (United States)

Fawaz, Khaled; Khaled, Fawaz; Smith, Myles J; Moises, Cukier; Smith, Andrew J; Yee, Albert J M

2014-03-01

A review of prospectively collected data on a consecutive series of patients undergoing single-stage anterior high sacrectomy for locally recurrent rectal carcinoma (LRRC). To determine the clinical outcome of patients who underwent anterior high sacrectomy for LRRC. High sacrectomy for oncological resection remains technically challenging. Surgery has the potential to achieve cure in carefully selected patients. Complete (R0) tumor excision in LRRC may require sacrectomy. High sacral resections (S3 and above) typically require a combined anterior/supine and posterior/prone procedure. We investigated our experience performing single-stage anterior high sacrectomy for LRRC. A consecutive series of patients with LRRC without systemic metastases who underwent resection with curative intent requiring high sacrectomy were identified. A review of a prospectively maintained colorectal and spine cancer database data was performed. An oblique dome high sacral osteotomy was performed during a single-stage anterior procedure. Outcome measures included surgical resection margin status, hospital length of stay, postoperative complications, physical functioning status, and overall survival. Nineteen consecutive patients were treated between 2002 and 2011. High sacrectomy was performed at sacral level S1-S2 in 4 patients, S2-S3 in 9 patients, and through S3 in 6 patients. An R0 resection margin was achieved histologically in all 19 cases. There was 1 early (<30 d) postoperative death (1/19, 5%). At median follow-up of 38 months, 13 patients had no evidence of residual disease, 1 was alive with disease, and 4 had died of disease. Morbidities occurred in 15 of the 19 patients (79%). Although high sacrectomy may require a combined anterior and posterior surgical approach, our series demonstrates the feasibility of performing single-stage anterior high sacrectomy in LRRC, with acceptable risks and outcomes compared with the literature. The procedure described by us for LRRC lessens

System and method for single-phase, single-stage grid-interactive inverter

Science.gov (United States)

Liu, Liming; Li, Hui

2015-09-01

The present invention provides for the integration of distributed renewable energy sources/storages utilizing a cascaded DC-AC inverter, thereby eliminating the need for a DC-DC converter. The ability to segment the energy sources and energy storages improves the maintenance capability and system reliability of the distributed generation system, as well as achieve wide range reactive power compensation. In the absence of a DC-DC converter, single stage energy conversion can be achieved to enhance energy conversion efficiency.

Strategies and limits in multi-stage single-point incremental forming

DEFF Research Database (Denmark)

Skjødt, Martin; Silva, M.B.; Martins, P. A. F.

2010-01-01

paths. The results also reveal that the sequence of multi-stage forming has a large effect on the location of strain points in the principal strain space. Strain paths are linear in the first stage and highly non-linear in the subsequent forming stages. The overall results show that the experimentally......Multi-stage single-point incremental forming (SPIF) is a state-of-the-art manufacturing process that allows small-quantity production of complex sheet metal parts with vertical walls. This paper is focused on the application of multi-stage SPIF with the objective of producing cylindrical cups......-limit curves and fracture forming-limit curves (FFLCs), numerical simulation, and experimentation, namely the evaluation of strain paths and fracture strains in actual multi-stage parts. Assessment of numerical simulation with experimentation shows good agreement between computed and measured strain and strain...

Evaluation of an automated single-channel sleep staging algorithm

Directory of Open Access Journals (Sweden)

Wang Y

2015-09-01

Full Text Available Ying Wang,1 Kenneth A Loparo,1,2 Monica R Kelly,3 Richard F Kaplan1 1General Sleep Corporation, Euclid, OH, 2Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH, 3Department of Psychology, University of Arizona, Tucson, AZ, USA Background: We previously published the performance evaluation of an automated electroencephalography (EEG-based single-channel sleep–wake detection algorithm called Z-ALG used by the Zmachine® sleep monitoring system. The objective of this paper is to evaluate the performance of a new algorithm called Z-PLUS, which further differentiates sleep as detected by Z-ALG into Light Sleep, Deep Sleep, and Rapid Eye Movement (REM Sleep, against laboratory polysomnography (PSG using a consensus of expert visual scorers. Methods: Single night, in-lab PSG recordings from 99 subjects (52F/47M, 18–60 years, median age 32.7 years, including both normal sleepers and those reporting a variety of sleep complaints consistent with chronic insomnia, sleep apnea, and restless leg syndrome, as well as those taking selective serotonin reuptake inhibitor/serotonin–norepinephrine reuptake inhibitor antidepressant medications, previously evaluated using Z-ALG were re-examined using Z-PLUS. EEG data collected from electrodes placed at the differential-mastoids (A1–A2 were processed by Z-ALG to determine wake and sleep, then those epochs detected as sleep were further processed by Z-PLUS to differentiate into Light Sleep, Deep Sleep, and REM. EEG data were visually scored by multiple certified polysomnographic technologists according to the Rechtschaffen and Kales criterion, and then combined using a majority-voting rule to create a PSG Consensus score file for each of the 99 subjects. Z-PLUS output was compared to the PSG Consensus score files for both epoch-by-epoch (eg, sensitivity, specificity, and kappa and sleep stage-related statistics (eg, Latency to Deep Sleep, Latency to REM

Use of skin stretchers for single-stage bilateral mastectomies in a dog and a cat.

Science.gov (United States)

Miyazaki, Yuta; Aikawa, Takeshi; Shimatsu, Taichi; Nishimura, Masaaki; Sadahiro, Shigeo

2018-04-01

To describe the application of skin stretchers for closure of single-stage bilateral mastectomies in a dog and a cat. Clinical case report. A 12-year-old intact female Miniature Dachshund and a 13-year-old spayed female domestic short-hair cat. Skin stretchers were applied to the site of the skin adjacent to mammary glands for 2-4 days before surgery. Cable tension was adjusted every 6-8 hours to elongate the skin and to achieve primary closure of single-stage bilateral mastectomy without tension. Wound closure after single-stage bilateral mastectomy was achieved without tension or major complication in both animals. Use of skin stretchers allows primary closure of single-stage bilateral mastectomy in dogs and cats. © 2017 The American College of Veterinary Surgeons.

Monitoring of trace chloride ions at different stages of the gas production process

Directory of Open Access Journals (Sweden)

A.Y. El Naggar

2015-01-01

Full Text Available Fifty gas and liquid samples at different stages of Obaiyed gas plant in Egypt were selected and subjected for determining chloride ion and hydrocarbon compositions. The trace levels of chloride in the water extracted from natural gas, condensate, Benfield and glycol samples were achieved using ion chromatograph (IC, electrical, conductivity and potentiometric methods, respectively. The hydrocarbon compositions were analyzed and evaluated using capillary gas chromatography. The chloride ions in natural gas and condensate are a function of water content and their concentration mainly depends on the separation efficiency. Variability in natural gas and condensate compositions seasonally is not an uncommon occurrence. Our aim is monitoring of chloride ion to select and optimize the conditions of sweetening and dehydration regenerators in order to follow and prevent their gradient in gas plant.

Modeling of filling gas centrifuge cascade for nickel isotope separation by feed flow input to different stages

Directory of Open Access Journals (Sweden)

Orlov Alexey A.

2017-01-01

Full Text Available The article presents results of research filling gas centrifuge cascade by process gas fed into different stages. The modeling of filling cascade was done for nickel isotope separation. Analysis of the research results shows that nickel isotope concentrations of light and heavy fraction flows after filling cascade depend on feed stage number.

One-dimensional simulation of a stirling three-stage pulse-tube refrigerator

NARCIS (Netherlands)

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

2009-01-01

A one-dimensional mathematical model is derived for a three-stage pulse-tube refrigerator (PTR) that is based on the conservation laws and the ideal gas law. The three-stage PTR is regarded as three separate single-stage PTRs that are coupled via proper junction conditions. At the junctions there

One-dimensional simulation of a Stirling three-stage pulse-tube refrigerator

NARCIS (Netherlands)

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

2009-01-01

A one-dimensional mathematical model is derived for a three-stage pulse-tube refrigerator (PTR) that is based on the conservation laws and the ideal gas law. The three-stage PTR is regarded as three separate single-stage PTRs that are coupled via proper junction conditions. At the junctions there

Stage 1: Expression of interest and consultation document for natural gas distribution in New Brunswick

International Nuclear Information System (INIS)

1998-01-01

The New Brunswick government intends to award a franchise to establish natural gas distribution in the province. To this end, the province wishes to invite bids from qualified entities to establish gas distribution facilities. The province will select the preferred bidder(s) through a two-stage competitive bidding process. This document details the province's policy objectives, questions and issues to be addressed in stage 1 of the process, and the schedule for the process. Appendices include copies of relevant provincial statutes and regulations

The efficacy of single-stage open intramedullary nailing of neglected femur fractures.

Science.gov (United States)

Boopalan, P R J V C; Sait, Azad; Jepegnanam, Thilak Samuel; Matthai, Thomas; Varghese, Viju Daniel

2014-02-01

Neglected femur fractures are not rare in the developing world. Treatment options include single-stage open reduction and intramedullary nailing, or open release, skeletal traction, and then second-stage open intramedullary nailing, with bone grafting. Single-stage procedures have the potential advantage of avoiding neurovascular complications secondary to acute lengthening, but they require a second operation, with potentially increased resource use and infection risk. We sought to determine the (1) likelihood of union, (2) complications and reoperations, and (3) functional results with single-stage open intramedullary nailing without bone grafting in patients with neglected femur fractures. Between January 2003 and December 2007, 17 consecutive patients presented to our practice with neglected femoral shaft fractures. All were treated with single-stage nailing without bone grafting. There were 15 men and two women with a median age of 27 years. The average time from fracture to treatment was 13 weeks (range, 4-44 weeks). Eleven patients underwent open nailing with interlocked nails and six were treated with cloverleaf Kuntscher nails. Patients were followed for a minimum of 6 months (mean, 33 months; range, 6-72 months). The mean preoperative ROM of the knee was 28° (range, 10°-150°) and femoral length discrepancy was 3.1 cm (range, 1-5 cm). All fractures united and the mean time to union was 16 weeks (range, 7-32 weeks). There were no neurologic complications secondary to acute lengthening. The mean postoperative ROM of the knee was 130° (range, 60°-150°). All patients were able to return to preinjury work. Sixteen patients regained their original femoral length. One-stage open intramedullary nailing of neglected femoral diaphyseal fractures without bone grafting was safe and effective, and obviated the need for a two-stage approach. Although the findings need to be replicated in larger numbers of patients, we believe this technique may be useful in

Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport.

Science.gov (United States)

Farjoo, Afrooz; Kuznicki, Steve M; Sadrzadeh, Mohtada

2017-10-06

Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene) was studied within the temperature and pressure ranges of 25-600 °C and 110-160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption-diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

Lean-rich axial stage combustion in a can-annular gas turbine engine

Science.gov (United States)

Laster, Walter R.; Szedlacsek, Peter

2016-06-14

An apparatus and method for lean/rich combustion in a gas turbine engine (10), which includes a combustor (12), a transition (14) and a combustor extender (16) that is positioned between the combustor (12) and the transition (14) to connect the combustor (12) to the transition (14). Openings (18) are formed along an outer surface (20) of the combustor extender (16). The gas turbine (10) also includes a fuel manifold (28) to extend along the outer surface (20) of the combustor extender (16), with fuel nozzles (30) to align with the respective openings (18). A method (200) for axial stage combustion in the gas turbine engine (10) is also presented.

Design of Single Stage Axial Turbine with Constant Nozzle Angle Blading for Small Turbojet

Science.gov (United States)

Putra Adnan, F.; Hartono, Firman

2018-04-01

In this paper, an aerodynamic design of a single stage gas generator axial turbine for small turbojet engine is explained. As per design requirement, the turbine should be able to deliver power output of 155 kW at 0.8139 kg/s gas mass flow, inlet total temperature of 1200 K and inlet total pressure of 335330 Pa. The design phase consist of several steps, i.e.: determination of velocity triangles in 2D plane, 2D blading design and 3D flow analysis at design point using Computational Fluid Dynamics method. In the determination of velocity triangles, two conditions are applied: zero inlet swirl (i.e. the gas flow enter the turbine at axial direction) and constant nozzle angle design (i.e. the inlet and outlet angle of the nozzle blade are constant from root to tip). The 2D approach in cascade plane is used to specify airfoil type at root, mean and tip of the blade based on inlet and outlet flow conditions. The 3D approach is done by simulating the turbine in full configuration to evaluate the overall performance of the turbine. The observed parameters including axial gap, stagger angle, and tip clearance affect its output power. Based on analysis results, axial gap and stagger angle are positively correlated with output power up to a certain point at which the power decreases. Tip clearance, however, gives inversely correlation with output power.

A 3-stage gated UV-photon gaseous detector with optical imaging

International Nuclear Information System (INIS)

Breskin, A.; Chechik, R.; Sauvage, D.

1989-03-01

UV-photons are detected by a low pressure photosensitive multistep gaseous detector. Photoelectrons are multiplied in two charge amplification stages. A third, light amplification stage operating in a scintillation mode, provides light yields >5.10 7 visible photons per single photoelectron avalanche, in Argon-C 2 H 6 -TMAE gas mixture. We present results on absolute photon yields in various TMAE gas mixtures, at low gas pressure and at low charge gains. We describe the operation mechanism and some basic properties of the gated 3-stage detectors, such as stability of operation at high background rates and localization resolutions particularly at large TMAE concentration and high temperature operation conditions. Further applications are discussed. (authors)

Two-stage gas-phase bioreactor for the combined removal of hydrogen sulphide, methanol and alpha-pinene.

Science.gov (United States)

Rene, Eldon R; Jin, Yaomin; Veiga, María C; Kennes, Christian

2009-11-01

Biological treatment systems have emerged as cost-effective and eco-friendly techniques for treating waste gases from process industries at moderately high gas flow rates and low pollutant concentrations. In this study, we have assessed the performance of a two-stage bioreactor, namely a biotrickling filter packed with pall rings (BTF, 1st stage) and a perlite + pall ring mixed biofilter (BF, 2nd stage) operated in series, for handling a complex mixture of hydrogen sulphide (H2S), methanol (CH3OH) and alpha-pinene (C10H16). It has been reported that the presence of H2S can reduce the biofiltration efficiency of volatile organic compounds (VOCs) when both are present in the gas mixture. Hydrogen sulphide and methanol were removed in the first stage BTF, previously inoculated with H2S-adapted populations and a culture containing Candida boidinii, an acid-tolerant yeast, whereas, in the second stage, alpha-pinene was removed predominantly by the fungus Ophiostoma stenoceras. Experiments were conducted in five different phases, corresponding to inlet loading rates varying between 2.1 and 93.5 g m(-3) h(-1) for H2S, 55.3 and 1260.2 g m(-3) h(-1) for methanol, and 2.8 and 161.1 g m(-3) h(-1) for alpha-pinene. Empty bed residence times were varied between 83.4 and 10 s in the first stage and 146.4 and 17.6 s in the second stage. The BTF, working at a pH as low as 2.7 as a result of H2S degradation, removed most of the H2S and methanol but only very little alpha-pinene. On the other hand, the BF, at a pH around 6.0, removed the rest of the H2S, the non-degraded methanol and most of the alpha-pinene vapours. Attempts were originally made to remove the three pollutants in a single acidophilic bioreactor, but the Ophiostoma strain was hardly active at pH elimination capacities (ECs) reached by the two-stage bioreactor for individual pollutants were 894.4 g m(-3) h(-1) for methanol, 45.1 g m(-3) h(-1) for H2S and 138.1 g m(-3) h(-1) for alpha-pinene. The results from this

The early stages of oxidation of magnesium single crystal surfaces

International Nuclear Information System (INIS)

Hayden, B.E.; Schweizer, E.; Koetz, R.; Bradshaw, A.M.

1981-01-01

The early stages of oxidation of Mg(001) and Mg(100) single crystal surfaces at 300 K have been investigated by LEED, ELS, work function and ellipsometric measurements. A sharp decrease in work function on both surfaces during the first 12 L exposure indicates the incorporation of oxygen in the earliest stages of the interaction. The incorporated oxygen on Mg(001) gives rise to a broadening of the integral order LEED spots for an exposure 3 L. (orig.)

Combustion of coal gas fuels in a staged combustor

Science.gov (United States)

Rosfjord, T. J.; Mcvey, J. B.; Sederquist, R. A.; Schultz, D. F.

1982-01-01

Gaseous fuels produced from coal resources generally have heating values much lower than natural gas; the low heating value could result in unstable or inefficient combustion. Coal gas fuels may contain ammonia which if oxidized in an uncontrolled manner could result in unacceptable nitrogen oxide exhaust emission levels. Previous investigations indicate that staged, rich-lean combustion represents a desirable approach to achieve stable, efficient, low nitrogen oxide emission operation for coal-derived liquid fuels contaning up to 0.8-wt pct nitrogen. An experimental program was conducted to determine whether this fuel tolerance can be extended to include coal-derived gaseous fuels. The results of tests with three nitrogen-free fuels having heating values of 100, 250, and 350 Btu/scf and a 250 Btu/scf heating value doped to contain 0.7 pct ammonia are presented.

A combined heating cooling stage for cluster thermalization in the gas phase

International Nuclear Information System (INIS)

Ievlev, D.N.; Kuester, A.; Enders, A.; Malinowski, N.; Schaber, H.; Kern, K.

2003-01-01

We report on the design and performance of a combined heating/cooling stage for the thermalization of clusters in a gas phase time-of-flight mass spectrometer. With this setup the cluster temperature can sensitively be adjusted within the range from 100 up to 800 K and higher. The unique combination of a heating stage with a subsequent cooling stage allows us to perform thermodynamic investigations on clusters at very high temperatures without quality losses in the spectra due to delayed fragmentation in the drift tube of the mass spectrometer. The performance of the setup is demonstrated by the example of (C 60 ) n clusters

Determination of blade-to-coolant heat-transfer coefficients on a forced-convection, water-cooled, single-stage turbine

Science.gov (United States)

Freche, John C; Schum, Eugene F

1951-01-01

Blade-to-coolant convective heat-transfer coefficients were obtained on a forced-convection water-cooled single-stage turbine over a large laminar flow range and over a portion of the transition range between laminar and turbulent flow. The convective coefficients were correlated by the general relation for forced-convection heat transfer with laminar flow. Natural-convection heat transfer was negligible for this turbine over the Grashof number range investigated. Comparison of turbine data with stationary tube data for the laminar flow of heated liquids showed good agreement. Calculated average midspan blade temperatures using theoretical gas-to-blade coefficients and blade-to-coolant coefficients from stationary-tube data resulted in close agreement with experimental data.

Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport

Directory of Open Access Journals (Sweden)

Afrooz Farjoo

2017-10-01

Full Text Available Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene was studied within the temperature and pressure ranges of 25–600 °C and 110–160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption–diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

Nitrite reduction and methanogenesis in a single-stage UASB reactor.

Science.gov (United States)

Borges, L I; López-Vazquez, C M; García, H; van Lier, J B

2015-01-01

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO(2)(-)-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO(2)(-)-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO(2)(-)-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO(2)(-) reduction to N₂. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

The Seepage Simulation of Single Hole and Composite Gas Drainage Based on LB Method

Science.gov (United States)

Chen, Yanhao; Zhong, Qiu; Gong, Zhenzhao

2018-01-01

Gas drainage is the most effective method to prevent and solve coal mine gas power disasters. It is very important to study the seepage flow law of gas in fissure coal gas. The LB method is a simplified computational model based on micro-scale, especially for the study of seepage problem. Based on fracture seepage mathematical model on the basis of single coal gas drainage, using the LB method during coal gas drainage of gas flow numerical simulation, this paper maps the single-hole drainage gas, symmetric slot and asymmetric slot, the different width of the slot combined drainage area gas flow under working condition of gas cloud of gas pressure, flow path diagram and flow velocity vector diagram, and analyses the influence on gas seepage field under various working conditions, and also discusses effective drainage method of the center hole slot on both sides, and preliminary exploration that is related to the combination of gas drainage has been carried on as well.

NOFBX Single-Stage-to-Orbit Mars Ascent Vehicle Engine, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — We propose the continuation of our research and development of a Nitrous Oxide Fuel Blend (NOFBXTM) Single-Stage-to-Orbit (SSTO) monopropellant propulsion system for...

Dynamic Optimal Energy Flow in the Integrated Natural Gas and Electrical Power Systems

DEFF Research Database (Denmark)

Fang, Jiakun; Zeng, Qing; Ai, Xiaomeng

2018-01-01

. Simulation on the test case illustrates the success of the modelling and the beneficial roles of the power-to-gas are analyzed. The proposed model can be used in the decision support for both planning and operation of the coordinated natural gas and electrical power systems.......This work focuses on the optimal operation of the integrated gas and electrical power system with bi-directional energy conversion. Considering the different response times of the gas and power systems, the transient gas flow and steady- state power flow are combined to formulate the dynamic...... optimal energy flow in the integrated gas and power systems. With proper assumptions and simplifications, the problem is transformed into a single stage linear programming. And only a single stage linear programming is needed to obtain the optimal operation strategy for both gas and power systems...

Staged membrane oxidation reactor system

Science.gov (United States)

Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

2012-09-11

Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis

OpenAIRE

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Zhang, Yupeng; Liu, Zheng

2015-01-01

Objective: The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation.Methods: Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reco...

Practical Considerations Concerning the Interleaved Transition Mode Single-stage Ballast

DEFF Research Database (Denmark)

Teodorescu, Remus; Kjær, Søren Bækhøj; Munk-Nielsen, Stig

2002-01-01

The aim of this paper is to present a novel single-stage interleaved ballast focusing on practical design aspects like: key current expression, overall losses, harmonic analysis of the differential-mode EMI current and preheating ballast function. A new preheating method is also presented. A PSPICE...

A portable high-power diode laser-based single-stage ceramic tile grout sealing system

Science.gov (United States)

Lawrence, J.; Schmidt, M. J. J.; Li, L.; Edwards, R. E.; Gale, A. W.

2002-02-01

By means of a 60 W high-power diode laser (HPDL) and a specially developed grout material the void between adjoining ceramic tiles has been successfully sealed. A single-stage process has been developed which uses a crushed ceramic tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. The single-stage ceramic tile grout sealing process yielded seals produced in normal atmospheric conditions that displayed no discernible cracks and porosities. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 200 kW/ mm2 and at rates of up to 600 mm/ min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves. What is more, the development of a hand-held HPDL beam delivery unit and the related procedures necessary to lead to the commercialisation of the single-stage ceramic tile grout sealing process are presented. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given.

Single-staged uniportal VATS in the supine position for simultaneous bilateral primary spontaneous pneumothorax.

Science.gov (United States)

Kim, Kyung Soo

2017-05-15

Simultaneous bilateral primary spontaneous pneumothorax (SBPSP) is rare, but requires surgery on both sides, in patients with definite bilateral bullae to prevent life-threatening conditions. Recently, uniportal video-assisted thoracoscopic surgery (VATS) has been widely accepted as a less invasive technique for the treatment of pneumothorax. Thus, we introduced single-staged uniportal VATS technique in the supine position, for the management of two cases of SBPSP. A 17-year-old boy presented with bilateral spontaneous pneumothorax and he underwent single-staged uniportal VATS in the supine position. Single wide draping in consecutive bilateral approaches removes the needs of changing patients' position. Whole thoracoscopic procedure for wedge resection of bullae lesions was conducted without difficulty. The total operation time took 65 min and the patient discharged 3 days after the operation. The patient was followed for 24 months without recurrence of both sides. Another 18-year-old boy was admitted with bilateral spontaneous pneumothorax and single-staged uniportal VATS was also performed in the supine position. The total operation time took 79 min and the patient discharged on postoperative day 4. He was followed for 19 months without recurrence of both sides. Single-staged uniportal VATS approach yielded satisfactory results from simplicity that not requires position change compared to conventional multi-ports VATS in the lateral position, and with better cosmetics. This technique is thought to be a feasible procedure in selective patients with SBPSP or with contralateral bullae for preventive role.

Surgical reconstruction of pressure ulcer defects: a single- or two-stage procedure?

LENUS (Irish Health Repository)

Laing, Tereze A

2012-02-01

BACKGROUND: The surgical management of pressure ulcers traditionally involved staged procedures, with initial debridement of necrotic or infected material followed by reconstruction at a later date when the wound was deemed viable and free of gross infection. However, over the past decade, it has been suggested that a single-stage procedure, combining initial debridement and definitive reconstruction, may provide advantages over staged surgery. We present our experience with the staged approach and review the current evidence for both methods. SUBJECTS AND SETTINGS: : We reviewed medical records of all patients referred to our service for pressure ulcer management between October 2001 and October 2007. The National Rehabilitation Hospital is the national center in Ireland for primary rehabilitation of adults and children suffering from spinal and brain injury, serving patients locally and from around the country. METHODS: All subjects who were managed surgically underwent a 2-stage procedure, with initial debridement and subsequent reconstruction. The main outcome measures were length of hospital stay, postoperative morbidity and mortality, and time to complete ulcer healing. RESULTS: Forty-one of 108 patients with 58 pressure ulcers were managed surgically. All patients underwent initial surgical debridement and 20 patients underwent subsequent pressure ulcer reconstruction. Postreconstructive complications occurred in 5 patients (20%). The mean time to complete ulcer healing was 17.4 weeks. Partial flap necrosis occurred in 3 patients, but there were no episodes of flap failure. CONCLUSIONS: We achieved favorable results with a 2-stage reconstruction technique and suggest that the paucity of evidence related to single-stage procedures does not support a change in surgical management.

INFLUENCE OF AXIAL COMPRESSOR STAGE SPATIAL OPTIMIZATION ON THRUST-ECONOMICAL CHARACTERISTICS OF CARGO AIRCRAFT GAS TURBINE ENGINE

Directory of Open Access Journals (Sweden)

L.G. Volyanskaya

2005-02-01

Full Text Available  The article considers the research results of D-27 gas turbine engine thrust-economical characteristics change due to of axial compressor flow path optimization. The applied procedure of optimization takes into account a difference in the shapes of axial compressor stage blades at rest and design mode, redistribution of kinetic energy losses along the blade height. The estimation of parameters of a gas flow in the stage flow path is made by the solution of Navier-Stokes equation complete set.

Computational Study on the Effect of Shroud Shape on the Efficiency of the Gas Turbine Stage

Science.gov (United States)

Afanas'ev, I. V.; Granovskii, A. V.

2018-03-01

The last stages of powerful power gas turbines play an important role in the development of power and efficiency of the whole unit as well as in the distribution of the flow parameters behind the last stage, which determines the efficient operation of the exhaust diffusers. Therefore, much attention is paid to improving the efficiency of the last stages of gas turbines as well as the distribution of flow parameters. Since the long blades of the last stages of multistage high-power gas turbines could fall into the resonance frequency range in the course of operation, which results in the destruction of the blades, damping wires or damping bolts are used for turning out of resonance frequencies. However, these damping elements cause additional energy losses leading to a reduction in the efficiency of the stage. To minimize these losses, dampening shrouds are used instead of wires and bolts at the periphery of the working blades. However, because of the strength problems, designers have to use, instead of the most efficient full shrouds, partial shrouds that do not provide for significantly reducing the losses in the tip clearance between the blade and the turbine housing. In this paper, a computational study is performed concerning an effect that the design of the shroud of the turbine-working blade exerted on the flow structure in the vicinity of the shroud and on the efficiency of the stage as a whole. The analysis of the flow structure has shown that a significant part of the losses under using the shrouds is associated with the formation of vortex zones in the cavities on the turbine housing before the shrouds, between the ribs of the shrouds, and in the cavities at the outlet behind the shrouds. All the investigated variants of a partial shrouding are inferior in efficiency to the stages with shrouds that completely cover the tip section of the working blade. The stage with a unshrouded working blade was most efficient at the values of the relative tip clearance

Detection of gas molecules on single Mn adatom adsorbed graphyne: a DFT-D study

Science.gov (United States)

Lu, Zhansheng; Lv, Peng; Ma, Dongwei; Yang, Xinwei; Li, Shuo; Yang, Zongxian

2018-02-01

As one of the prominent applications in intelligent systems, gas sensing technology has attracted great interest in both industry and academia. In the current study, the pristine graphyne (GY) without and with a single Mn atom is investigated to detect the gas molecules (CO, CH4, CO2, NH3, NO and O2). The pristine GY is promising to detect O2 molecules because of its chemical adsorption on GY with large electron transfer. The great stability of the Mn/GY is found, and the Mn atom prefers to anchor at the alkyne ring as a single atom. Upon single Mn atom anchoring, the sensitivity and selectivity of GY based gas sensors is significantly improved for various molecules, except CH4. The recovery time of the Mn/GY after detecting the gas molecules may help to appraise the detection efficiency for the Mn/GY. The current study will help to understand the mechanism of detecting the gas molecules, and extend the potentially fascinating applications of GY-based materials.

Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter.

Science.gov (United States)

Vizir, A V; Tyunkov, A V; Shandrikov, M V; Oks, E M

2010-02-01

The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x10(9) cm(-3) at an operating gas pressure in the vacuum chamber of less than 2x10(-2) Pa. The device features high power efficiency, design simplicity, and compactness.

Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter

International Nuclear Information System (INIS)

Vizir, A. V.; Tyunkov, A. V.; Shandrikov, M. V.; Oks, E. M.

2010-01-01

The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x10 9 cm -3 at an operating gas pressure in the vacuum chamber of less than 2x10 -2 Pa. The device features high power efficiency, design simplicity, and compactness.

Single-stage osseointegrated implants for nasal prosthodontic rehabilitation: A clinical report.

Science.gov (United States)

de Carvalho, Bruna M D F; Freitas-Pontes, Karina M; de Negreiros, Wagner A; Verde, Marcus A R L

2015-08-01

Malignant tumors in the nasal region may be treated by means of invasive surgical procedures, with large facial losses. Nasal prostheses, retained by osseointegrated facial implants, instead of plastic surgery, will, in most patients, offer good biomechanical and cosmetic results. This clinical report describes the prosthetic rehabilitation of a patient with nasal cancer who had the entire nasal vestibule removed in a single-stage surgical procedure in order to shorten the rehabilitation time. The nasal prosthesis was built on a 3-magnet bar and was made of platinum silicone with intrinsic pigmentation, thereby restoring the patient's appearance and self-esteem. The authors concluded that single-stage implants may reduce the rehabilitation time to as little as 1 month, and the correct use of materials and techniques may significantly improve the nasal prosthesis. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Recording single neurons' action potentials from freely moving pigeons across three stages of learning.

Science.gov (United States)

Starosta, Sarah; Stüttgen, Maik C; Güntürkün, Onur

2014-06-02

While the subject of learning has attracted immense interest from both behavioral and neural scientists, only relatively few investigators have observed single-neuron activity while animals are acquiring an operantly conditioned response, or when that response is extinguished. But even in these cases, observation periods usually encompass only a single stage of learning, i.e. acquisition or extinction, but not both (exceptions include protocols employing reversal learning; see Bingman et al.(1) for an example). However, acquisition and extinction entail different learning mechanisms and are therefore expected to be accompanied by different types and/or loci of neural plasticity. Accordingly, we developed a behavioral paradigm which institutes three stages of learning in a single behavioral session and which is well suited for the simultaneous recording of single neurons' action potentials. Animals are trained on a single-interval forced choice task which requires mapping each of two possible choice responses to the presentation of different novel visual stimuli (acquisition). After having reached a predefined performance criterion, one of the two choice responses is no longer reinforced (extinction). Following a certain decrement in performance level, correct responses are reinforced again (reacquisition). By using a new set of stimuli in every session, animals can undergo the acquisition-extinction-reacquisition process repeatedly. Because all three stages of learning occur in a single behavioral session, the paradigm is ideal for the simultaneous observation of the spiking output of multiple single neurons. We use pigeons as model systems, but the task can easily be adapted to any other species capable of conditioned discrimination learning.

Two-stage single-volume exchange transfusion in severe hemolytic disease of the newborn.

Science.gov (United States)

Abbas, Wael; Attia, Nayera I; Hassanein, Sahar M A

2012-07-01

Evaluation of two-stage single-volume exchange transfusion (TSSV-ET) in decreasing the post-exchange rebound increase in serum bilirubin level, with subsequent reduction of the need for repeated exchange transfusions. The study included 104 neonates with hyperbilirubinemia needing exchange transfusion. They were randomly enrolled into two equal groups, each group comprised 52 neonates. TSSV-ET was performed for the 52 neonates and the traditional single-stage double-volume exchange transfusion (SSDV-ET) was performed to 52 neonates. TSSV-ET significantly lowered rebound serum bilirubin level (12.7 ± 1.1 mg/dL), compared to SSDV-ET (17.3 ± 1.7 mg/dL), p < 0.001. Need for repeated exchange transfusions was significantly lower in TSSV-ET group (13.5%), compared to 32.7% in SSDV-ET group, p < 0.05. No significant difference was found between the two groups as regards the morbidity (11.5% and 9.6%, respectively) and the mortality (1.9% for both groups). Two-stage single-volume exchange transfusion proved to be more effective in reducing rebound serum bilirubin level post-exchange and in decreasing the need for repeated exchange transfusions.

AGT101 automotive gas turbine system development

Science.gov (United States)

Rackley, R. A.; Kidwell, J. R.

1982-01-01

The AGT101 automotive gas turbine system consisting of a 74.6 kw regenerated single-shaft gas turbine engine, is presented. The development and testing of the system is reviewed, and results for aerothermodynamic components indicate that compressor and turbine performance levels are within one percent of projected levels. Ceramic turbine rotor development is encouraging with successful cold spin testing of simulated rotors to speeds over 12,043 rad/sec. Spin test results demonstrate that ceramic materials having the required strength levels can be fabricated by net shape techniques to the thick hub cross section, which verifies the feasibility of the single-stage radial rotor in single-shaft engines.

FLAMMABLE GAS DIFFUSION THROUGH SINGLE SHELL TANK (SST) DOMES

Energy Technology Data Exchange (ETDEWEB)

MEACHAM, J.E.

2003-11-10

This report quantified potential hydrogen diffusion through Hanford Site Single-Shell tank (SST) domes if the SSTs were hypothetically sealed airtight. Results showed that diffusion would keep headspace flammable gas concentrations below the lower flammability limit in the 241-AX and 241-SX SST. The purpose of this document is to quantify the amount of hydrogen that could diffuse through the domes of the SSTs if they were hypothetically sealed airtight. Diffusion is assumed to be the only mechanism available to reduce flammable gas concentrations. The scope of this report is limited to the 149 SSTs.

Use of a two-stage light-gas gun as an injector for electromagnetic railguns

International Nuclear Information System (INIS)

Shahinpoor, M.

1989-01-01

Ablation of wall materials is known to be a major factor limiting the performance of railguns. To minimize this effect, it is desirable too inject projectiles into railgun at velocities greater than the ablation threshold velocity (6-8 km/s for copper rails). Because two-stage light-gas guns are capable of achieving such velocities, a program was initiated to design, build and evaluate the performance of a two-stage light gas gun, utilizing hydrogen gas, for use as an injector to an electromagnetic railgun. This effort is part of a project to develop a hypervelocity electromagnetic launcher (HELEOS) for use in equation-of-state studies. In this paper, the specific design features that enhance compatibility of the injector with the railgun, including a slip-joint between the injector launch tube and the coupling section to the railgun are described. The operational capabilities for using all major projectile velocity measuring techniques, such as in-bore pressure gauges, laser and CW x-ray interrupt techniques, flash x-ray and continuous in-bore velocity measurements using VISAR interferometry are also discussed. Finally an internal ballistics code for optimizing gun performance has been utilized to interpret performance data of the gun

Single-stage micro-scale solvent extraction in parallel microbore tubes using MDIMJ

International Nuclear Information System (INIS)

Darekar, Mayur; Singh, K.K.; Joshi, J.M.; Mukhopadhyay, S.; Shenoy, K.T.

2016-01-01

Single-stage micro-scale solvent extraction of U(VI) from simulated lean streams is explored using micro-scale contactor comprising of a MDIMJ (Monoblock Distributor with Integrated Microfluidic Junction) and PTFE microbore tubes. 30% (v/v) TBP in dodecane has been used as the extracting phase. The objective of the study is to demonstrate numbering up approach for scale-up of micro-scale extraction using indigenously conceptualized and fabricated MDIMJ. First the performance of MIDIMJ for equal flow distribution is tested. Then the effects of inlet flow rate and O/A ratio on stage efficiency and percentage extraction are studied. The experiments show that it is easy to scale-up single-stage micro-scale solvent extraction by using MDIMJ for numbering up approach. Maximum capacity tested is 4.8 LPH. With O/A = 2/1, more than 90% extraction is achieved in a very short contact time of less than 3s. The study thus demonstrates possibility of process intensification and easy scale-up of micro-scale solvent extraction

[Effects of different water potentials on leaf gas exchange and chlorophyll fluorescence parameters of cucumber during post-flowering growth stage].

Science.gov (United States)

Lin, Lu; Tang, Yun; Zhang, Ji-tao; Yan, Wan-li; Xiao, Jian-hong; Ding, Chao; Dong, Chuan; Ji, Zeng-shun

2015-07-01

Impacts of different substrate water potentials (SWP) on leaf gas exchange and chlorophyll fluorescence parameters of greenhouse cucumber during its post-flowering growth stage were analyzed in this study. The results demonstrated that -10 and -30 kPa were the critical values for initiating stomatal and non-stomatal limitation of drought stress, respectively. During the stage of no drought stress (-10 kPa gas exchange parameters and chlorophyll fluorescence parameters were not different significantly among treatments. During the stage of stomatal limitation of drought stress (-30 kPawater use efficiency (WUEi) and non-photochemical quenching (qN) increased. In this stage, gas exchange parameters changed faster than chlorophyll fluorescence parameters and differed significantly among treatments. During the stage of non-stomatal limitation of drought stress (-45 kPa≤SWP ≤ -30 kPa), with the decrease of SWP, light saturation point (LSP), Rd, CE, Vcmax, VTPU, LS, WUEi, ΦpPSII, Fv/Fm and qp decreased, while CCP, Ci and qN increased. In this stage, chlorophyll fluorescence parameters changed faster than gas exchange parameters and differed significantly among treatments. In production of greenhouse cucumber, -10 and -5 kPa should be the lower and upper limit value of irrigation, respectively. The stomatal limitation of drought stress could be relieved by irrigation before SWP decreased to -30 kPa. While, the non-stomatal injury of drought stress would be unrecoverable once SWP decreased to lower than -30 kPa.

Callus Distraction Versus Single-Stage Lengthening With Bone Graft for Treatment of Brachymetatarsia: A Systematic Review.

Science.gov (United States)

Jones, Marc D; Pinegar, David M; Rincker, Sarah A

2015-01-01

Brachymetatarsia deformity is a cosmetically displeasing anomaly that can become physically symptomatic. The surgical techniques most commonly used to repair the anomaly include single-stage lengthening with a bone graft, callus distraction, or a combination of bone grafting and callus distraction. A systematic review of the published data was performed to compare the outcomes of these 3 surgical procedures. A total of 61 studies reporting the use of callus distraction or single-stage lengthening, or both, for the treatment of brachymetatarsia were included in the present review. The incidence of major postoperative complications after callus distraction, single-stage lengthening, and the combination procedure was 49 (12.62%), 13 (3.72%), and 3 (33.33%), respectively. The number of minor complications with callus distraction, single-stage lengthening, and the combination procedure was 152 (39.18%), 55 (15.76%), and 1 (11.11%); the mean percentage of the original length achieved was 37.36%, 25.98% and 36.00%; and the mean length achieved was 17.5, 13.2, and 14.0 mm, respectively. The healing index (mo/cm) and healing time was 2.31 and 16.04 weeks, 1.90 and 9.35 weeks, and 3.93 and 14.62 weeks for callus distraction, single-stage lengthening, and the combination procedure, respectively. Our findings indicate that the callus distraction technique is associated with greater length gained but results in greater complication rates and requires almost twice the time to heal. Single-stage lengthening with a bone graft was associated with fewer complications and faster healing times than callus distraction but with lesser gains in length. From the information reported in the studies we reviewed, the prevalence of bilateral brachymetatarsia was 44.52%, and the female/male ratio was 13.7:1. Both of these findings seem to contradict the usual data given (72% for bilateral brachymetatarsia and a female/male ratio of 25:1). Copyright © 2015 American College of Foot and

Fill Rates of Single-Stage and Multistage Supply Systems

OpenAIRE

Matthew J. Sobel

2004-01-01

A supply system's fill rate is the fraction of demand that is met from on-hand inventory. This paper presents formulas for the fill rate of periodic review supply systems that use base-stock-level policies. The first part of the paper contains fill-rate formulas for a single-stage system and general distributions of demand. When demand is normally distributed, an exact expression uses only the standard normal distribution and density functions, and a good approximation uses only the standard ...

Staged fuel and air injection in combustion systems of gas turbines

Science.gov (United States)

Hughes, Michael John; Berry, Jonathan Dwight

2018-04-17

A gas turbine that includes a working fluid flowpath extending aftward from a forward injector in a combustor. The combustor may include an inner radial wall, an outer radial wall, and, therebetween, a flow annulus. A staged injector may intersect the flow annulus so to attain an injection point within the working fluid flowpath by which aftward and forward annulus sections are defined. Air directing structure may include an aftward intake section that corresponds to the aftward annulus section and a forward intake section that corresponds to the forward annulus section. The air directing structure may be configured to: direct air entering through the aftward intake section through the aftward annulus section in a forward direction to the staged injector; and direct air entering through the forward intake section through the forward annulus section in a forward direction to the forward injector.

Multiscale modelling of single crystal superalloys for gas turbine blades

NARCIS (Netherlands)

Tinga, T.

2009-01-01

Gas turbines are extensively used for power generation and for the propulsion of aircraft and vessels. Their most severely loaded parts, the turbine rotor blades, are manufactured from single crystal nickel-base superalloys. The superior high temperature behaviour of these materials is attributed to

Power control system for a hot gas engine

Science.gov (United States)

Berntell, John O.

1986-01-01

A power control system for a hot gas engine of the type in which the power output is controlled by varying the mean pressure of the working gas charge in the engine has according to the present invention been provided with two working gas reservoirs at substantially different pressure levels. At working gas pressures below the lower of said levels the high pressure gas reservoir is cut out from the control system, and at higher pressures the low pressure gas reservoir is cut out from the system, thereby enabling a single one-stage compressor to handle gas within a wide pressure range at a low compression ratio.

Two-stage light-gas magnetoplasma accelerator for hypervelocity impact simulation

International Nuclear Information System (INIS)

Khramtsov, P P; Vasetskij, V A; Makhnach, A I; Grishenko, V M; Chernik, M Yu; Shikh, I A; Doroshko, M V

2016-01-01

The development of macroparticles acceleration methods for high-speed impact simulation in a laboratory is an actual problem due to increasing of space flights duration and necessity of providing adequate spacecraft protection against micrometeoroid and space debris impacts. This paper presents results of experimental study of a two-stage light- gas magnetoplasma launcher for acceleration of a macroparticle, in which a coaxial plasma accelerator creates a shock wave in a high-pressure channel filled with light gas. Graphite and steel spheres with diameter of 2.5-4 mm were used as a projectile and were accelerated to the speed of 0.8-4.8 km/s. A launching of particle occurred in vacuum. For projectile velocity control the speed measuring method was developed. The error of this metod does not exceed 5%. The process of projectile flight from the barrel and the process of a particle collision with a target were registered by use of high-speed camera. The results of projectile collision with elements of meteoroid shielding are presented. In order to increase the projectile velocity, the high-pressure channel should be filled with hydrogen. However, we used helium in our experiments for safety reasons. Therefore, we can expect that the range of mass and velocity of the accelerated particles can be extended by use of hydrogen as an accelerating gas. (paper)

Two-stage light-gas magnetoplasma accelerator for hypervelocity impact simulation

Science.gov (United States)

Khramtsov, P. P.; Vasetskij, V. A.; Makhnach, A. I.; Grishenko, V. M.; Chernik, M. Yu; Shikh, I. A.; Doroshko, M. V.

2016-11-01

The development of macroparticles acceleration methods for high-speed impact simulation in a laboratory is an actual problem due to increasing of space flights duration and necessity of providing adequate spacecraft protection against micrometeoroid and space debris impacts. This paper presents results of experimental study of a two-stage light- gas magnetoplasma launcher for acceleration of a macroparticle, in which a coaxial plasma accelerator creates a shock wave in a high-pressure channel filled with light gas. Graphite and steel spheres with diameter of 2.5-4 mm were used as a projectile and were accelerated to the speed of 0.8-4.8 km/s. A launching of particle occurred in vacuum. For projectile velocity control the speed measuring method was developed. The error of this metod does not exceed 5%. The process of projectile flight from the barrel and the process of a particle collision with a target were registered by use of high-speed camera. The results of projectile collision with elements of meteoroid shielding are presented. In order to increase the projectile velocity, the high-pressure channel should be filled with hydrogen. However, we used helium in our experiments for safety reasons. Therefore, we can expect that the range of mass and velocity of the accelerated particles can be extended by use of hydrogen as an accelerating gas.

High peak-power kilohertz laser system employing single-stage multi-pass amplification

Science.gov (United States)

Shan, Bing; Wang, Chun; Chang, Zenghu

2006-05-23

The present invention describes a technique for achieving high peak power output in a laser employing single-stage, multi-pass amplification. High gain is achieved by employing a very small "seed" beam diameter in gain medium, and maintaining the small beam diameter for multiple high-gain pre-amplification passes through a pumped gain medium, then leading the beam out of the amplifier cavity, changing the beam diameter and sending it back to the amplifier cavity for additional, high-power amplification passes through the gain medium. In these power amplification passes, the beam diameter in gain medium is increased and carefully matched to the pump laser's beam diameter for high efficiency extraction of energy from the pumped gain medium. A method of "grooming" the beam by means of a far-field spatial filter in the process of changing the beam size within the single-stage amplifier is also described.

Mass-transfer in extraction and reextraction as a single-stage process

International Nuclear Information System (INIS)

Rodriguez del Cerro, M.; Trilleros, J.A.; Otero de la Gandara, J.L.

1987-01-01

The rate of mass transfer between water and naftenic acid and threebutilphosphate in kerosen are studied in the two possibilities to or from water. The two insoluble phases are brought in to intimate contact with dispersed phase droplets, in a single-stage process. The evolution of the equilibrium distribution of solute is taken in consideration. (author)

Millijoule Pulse Energy Second Harmonic Generation With Single-Stage Photonic Bandgap Rod Fiber Laser

DEFF Research Database (Denmark)

Laurila, Marko; Saby, Julien; Alkeskjold, Thomas Tanggaard

2011-01-01

In this paper, we demonstrate, for the first time, a single-stage Q-switched single-mode (SM) ytterbium-doped rod fiber laser delivering record breaking pulse energies at visible and UV light. We use a photonic bandgap rod fiber with a mode field diameter of 59μm based on a new distributed...

Staged fuel and air injection in combustion systems of gas turbines

Energy Technology Data Exchange (ETDEWEB)

Hughes, Michael John; Berry, Jonathan Dwight

2018-04-10

A gas turbine including a working fluid flowpath extending aftward from a forward injector in a combustor. The combustor may include an inner radial wall, an outer radial wall, and, therebetween, a flow annulus, and a third radial wall formed about the outer radial wall that forms an outer flow annulus. A staged injector may intersect the flow annulus so to attain an injection point within the working fluid flowpath by which aftward and forward annulus sections are defined. Air directing structure may include an aftward intake section corresponding to the aftward annulus section and a forward intake section corresponding to the forward annulus section. The air directing structure may include a switchback coolant flowpath to direct air from the compressor discharge cavity to the staged injector. The switchback coolant flowpath may include an upstream section through the flow annulus, and a downstream section through the outer flow annulus.

Two-stage combustion for reducing pollutant emissions from gas turbine combustors

Science.gov (United States)

Clayton, R. M.; Lewis, D. H.

1981-01-01

Combustion and emission results are presented for a premix combustor fueled with admixtures of JP5 with neat H2 and of JP5 with simulated partial-oxidation product gas. The combustor was operated with inlet-air state conditions typical of cruise power for high performance aviation engines. Ultralow NOx, CO and HC emissions and extended lean burning limits were achieved simultaneously. Laboratory scale studies of the non-catalyzed rich-burning characteristics of several paraffin-series hydrocarbon fuels and of JP5 showed sooting limits at equivalence ratios of about 2.0 and that in order to achieve very rich sootless burning it is necessary to premix the reactants thoroughly and to use high levels of air preheat. The application of two-stage combustion for the reduction of fuel NOx was reviewed. An experimental combustor designed and constructed for two-stage combustion experiments is described.

A two-stage biological gas to liquid transfer process to convert carbon dioxide into bioplastic

KAUST Repository

Al Rowaihi, Israa; Kick, Benjamin; Grö tzinger, Stefan W.; Burger, Christian; Karan, Ram; Weuster-Botz, Dirk; Eppinger, Jö rg; Arold, Stefan T.

2018-01-01

The fermentation of carbon dioxide (CO2) with hydrogen (H2) uses available low-cost gases to synthesis acetic acid. Here, we present a two-stage biological process that allows the gas to liquid transfer (Bio-GTL) of CO2 into the biopolymer

A high-order positivity-preserving single-stage single-step method for the ideal magnetohydrodynamic equations

Science.gov (United States)

Christlieb, Andrew J.; Feng, Xiao; Seal, David C.; Tang, Qi

2016-07-01

We propose a high-order finite difference weighted ENO (WENO) method for the ideal magnetohydrodynamics (MHD) equations. The proposed method is single-stage (i.e., it has no internal stages to store), single-step (i.e., it has no time history that needs to be stored), maintains a discrete divergence-free condition on the magnetic field, and has the capacity to preserve the positivity of the density and pressure. To accomplish this, we use a Taylor discretization of the Picard integral formulation (PIF) of the finite difference WENO method proposed in Christlieb et al. (2015) [23], where the focus is on a high-order discretization of the fluxes (as opposed to the conserved variables). We use the version where fluxes are expanded to third-order accuracy in time, and for the fluid variables space is discretized using the classical fifth-order finite difference WENO discretization. We use constrained transport in order to obtain divergence-free magnetic fields, which means that we simultaneously evolve the magnetohydrodynamic (that has an evolution equation for the magnetic field) and magnetic potential equations alongside each other, and set the magnetic field to be the (discrete) curl of the magnetic potential after each time step. In this work, we compute these derivatives to fourth-order accuracy. In order to retain a single-stage, single-step method, we develop a novel Lax-Wendroff discretization for the evolution of the magnetic potential, where we start with technology used for Hamilton-Jacobi equations in order to construct a non-oscillatory magnetic field. The end result is an algorithm that is similar to our previous work Christlieb et al. (2014) [8], but this time the time stepping is replaced through a Taylor method with the addition of a positivity-preserving limiter. Finally, positivity preservation is realized by introducing a parameterized flux limiter that considers a linear combination of high and low-order numerical fluxes. The choice of the free

The study on a gas-coupled two-stage stirling-type pulse tube cryocooler

Science.gov (United States)

Wu, X. L.; Chen, L. B.; Zhu, X. S.; Pan, C. Z.; Guo, J.; Wang, J. J.; Zhou, Y.

2017-12-01

A two-stage gas-coupled Stirling-type pulse tube cryocooler (SPTC) driven by a linear dual-opposed compressor has been designed, manufactured and tested. Both of the stages adopted coaxial structure for compactness. The effect of a cold double-inlet at the second stage on the cooling performance was investigated. The test results show that the cold double-inlet will help to achieve a lower cooling temperature, but it is not conducive to achieving a higher cooling capacity. At present, without the cold double-inlet, the second stage has achieved a no-load temperature of 11.28 K and a cooling capacity of 620 mW/20 K with an input electric power of 450 W. With the cold double-inlet, the no-load temperature is lowered to 9.4 K, but the cooling capacity is reduced to 400 mW/20 K. The structure of the developed cryocooler and the influences of charge pressure, operating frequency and hot end temperature will also be introduced in this paper.

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis.

Science.gov (United States)

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Liu, Zheng; Zhang, Yupeng

2015-01-01

The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. The mean follow-up was 36.9 months (range: 24-62 months). The kyphotic angle ranged from 15.2-35.1° preoperatively, with an average measurement of 27.8°. The American Spinal Injury Association (ASIA) score system was used to evaluate the neurological deficits and erythrocyte sedimentation rate (ESR) used to judge the activity of TB. Spinal TB was completely cured in all 17 patients. There was no recurrent TB infection. The postoperative kyphotic angle was 6.6-10.2°, 8.1° in average, and there was no significant loss of the correction at final follow-up. Solid fusion was achieved in all cases. Neurological condition in all patients was improved after surgery. Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation can be a feasible and effective method the in treatment of single-segment lumbar spinal TB.

Adaptive kanban control mechanism for a single-stage hybrid system

Science.gov (United States)

Korugan, Aybek; Gupta, Surendra M.

2002-02-01

In this paper, we consider a hybrid manufacturing system with two discrete production lines. Here the output of either production line can satisfy the demand for the same type of product without any penalties. The interarrival times for demand occurrences and service completions are exponentially distributed i.i.d. variables. In order to control this type of manufacturing system we suggest a single stage pull type control mechanism with adaptive kanbans and state independent routing of the production information.

New current control based MPPT technique for single stage grid connected PV systems

International Nuclear Information System (INIS)

Jain, Sachin; Agarwal, Vivek

2007-01-01

This paper presents a new maximum power point tracking algorithm based on current control for a single stage grid connected photovoltaic system. The main advantage of this algorithm comes from its ability to predict the approximate amplitude of the reference current waveform or power that can be derived from the PV array with the help of an intermediate variable β. A variable step size for the change in reference amplitude during initial tracking helps in fast tracking. It is observed that if the reference current amplitude is greater than the array capacity, the system gets unstable (i.e. moves into the positive slope region of the p-v characteristics of the array). The proposed algorithm prevents the PV system from entering the positive slope region of the p-v characteristics. It is also capable of restoring stability if the system goes unstable due to a sudden environmental change. The proposed algorithm has been tested on a new single stage grid connected PV configuration recently developed by the authors to feed sinusoidal current into the grid. The system is operated in a continuous conduction mode to realize advantages such as low device current stress, high efficiency and low EMI. A fast MPPT tracker with single stage inverter topology operating in CCM makes the overall system highly efficient. Specific cases of the system, operating in just discontinuous current mode and discontinuous current mode and their relative merits and demerits are also discussed

Numerical Study of the Working Process in the Reducing Gas Generator of the Upper Stage Oxygen - Methane Engine

Directory of Open Access Journals (Sweden)

D. M. Yagodnikov

2015-01-01

Full Text Available This article deals with the problems of creating a reducing gas generator of the liquid rocket engine (LRE of upper stage using advanced fuel components, namely oxygen + liquid natural gas. Relevance of the work is justified by the need to create and develop of environmentally friendly missile systems for space applications using methane-based fuel (liquid natural gas. As compared to the currently used unsymmetrical dimethyl-hydrazine and kerosene, this fuel is environmentally safe, passive to corrosion, has better cooling properties and high energy characteristics in the re-generatively cooled chambers, as well as is advantageous for LRE of multiple start and use.The purpose of this work is a mathematical modeling, calculation of the working process efficiency, as well as study of gas-dynamic structure of the flow in the gas generator flow path. The object of study is the upper stage LRE gas generator, which uses the reducing scheme on the liquid propellants: oxygen + liquid methane. Research methods are based on numerical simulation.Computational studies allowed us to receive the velocity, temperatures, and concentrations of reactants and combustion products in the longitudinal section of gas generator. Analysis of the gas-dynamic structure of flow shows a complete equalization of the velocity field by 2/3 of the gas generator length. Thus, the same distance is not enough to equalize the temperature distribution of the gasification products and their concentrations in radius. Increasing the total excess oxidant ratio from 0.15 to 0.25 leads to a greater spread of the parameters at the exit of the gas generator by ~ 13 ÷ 17%. As a recommendation to reduce the size of the working area, is proposed a dual-zone gas generator-mixing scheme with fuel separately supplied to the first and second zones.

The Incidence of Complications in Single-stage Endoscopic Stone Removal for Patients with Common Bile Duct Stones: A Propensity Score Analysis.

Science.gov (United States)

Saito, Hirokazu; Kadono, Yoshihiro; Kamikawa, Kentaro; Urata, Atsushi; Imamura, Haruo; Matsushita, Ikuo; Kakuma, Tatsuyuki; Tada, Shuji

2018-02-15

Objective Single-stage endoscopic stone removal for choledocholithiasis is an advantageous approach because it is associated with a shorter hospital stay; however, few studies have reported the incidence of complications related to this procedure in detail. The aim of this study was to examine the incidence of complications and efficacy of this procedure. Methods This retrospective study investigated the incidence of complications in 345 patients with naive papilla who underwent therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for choledocholithiasis at three institutions between April 2014 and March 2016 by a propensity score analysis. The efficacy of single-stage endoscopic stone removal was assessed based on a hospital stay of within 7 days and the number of ERCP attempts. Results Among 114 patients who underwent single-stage endoscopic stone removal, 15 patients (13.2%) experienced complications. Among the remaining 231 patients in the two-stage endoscopic stone removal group, complications were observed in 17 patients (7.4%). The propensity score analysis, which was adjusted for confounding factors, revealed that single-stage endoscopic stone removal was not a significant risk factor for complications (p=0.52). In patients in whom >10 min was required for deep cannulation, single-stage endoscopic stone removal was not a significant risk factor for complications in the propensity score analysis (p=0.37). In the single-stage group, the proportion of patients with a hospital stay of within 7 days was significantly higher and the number of ERCP attempts was significantly lower in comparison to the two-stage group (p <0.0001 and <0.0001, respectively). Conclusion Single-stage endoscopic stone removal did not increase the incidence of complications associated with ERCP and was effective for reducing the hospital stay and the number of ERCP attempts.

A tetrad of bicuspid aortic valve association: A single-stage repair

Science.gov (United States)

Barik, Ramachandra; Patnaik, A. N.; Mishra, Ramesh C.; Kumari, N. Rama; Gulati, A. S.

2012-01-01

We report a 27 years old male who presented with a combination of both congenital and acquired cardiac defects. This syndrome complex includes congenital bicuspid aortic valve, Seller's grade II aortic regurgitation, juxta- subclavian coarctation, stenosis of ostium of left subclavian artery and ruptured sinus of Valsalva aneurysm without any evidence of infective endocarditis. This type of constellation is extremely rare. Neither coarctation of aorta with left subclavian artery stenosis nor the rupture of sinus Valsalva had a favorable pathology for percutaneus intervention. Taking account into morbidity associated with repeated surgery and anesthesia patient underwent a single stage surgical repair of both the defects by two surgical incisions. The approaches include median sternotomy for rupture of sinus of Valsalva and lateral thoracotomy for coarctation with left subclavian artery stenosis. The surgery was uneventful. After three months follow up echocardiography showed mild residual gradient across the repaired coarctation segment, mild aortic regurgitation and no residual left to right shunt. This patient is under follow up. This is an extremely rare case of single stage successful repair of coarctation and rupture of sinus of Valsalva associated with congenital bicuspid aortic valve. PMID:22629035

Large Conization and Laparoendoscopic Single-Port Pelvic Lymphadenectomy in Early-Stage Cervical Cancer for Fertility Preservation

Directory of Open Access Journals (Sweden)

Polat Dursun

2013-01-01

Full Text Available Fertility preservation in early-stage cervical cancer is a hot topic in gynecologic oncology. Although radical vaginal trachelectomy (RVT is suggested as a fertility preserving approach, there are some serious concerns like cervical stenosis, second trimester loss, preterm delivery in survivors, and lack of residual tumor in the majority of the surgical specimens. Therefore, less radical surgical operations have been proposed in early-stage cervical carcinomas. On the other hand, single-incision laparoscopic surgery (SILS is an evolving endoscopic approach for minimal access surgery. In this report, we present a case with early-stage cervical cancer who wishes to preserve fertility. We successfully performed single-port pelvic lymphadenectomy and large conization to preserve fertility potential of the patient. We think that combination of less radical approach like conization and single-port pelvic lymphadenectomy might be less minimally invasive and is still an effective surgical approach in well-selected cases with cervical carcinomas. Incorporation of single-port laparoscopy into the minimally invasive fertility sparing management of the cervical cancer will improve patients outcome with less complications and better cosmesis. Further studies are needed to reach a clear conclusion.

Optimal analysis of gas cooler and intercooler for two-stage CO2 trans-critical refrigeration system

International Nuclear Information System (INIS)

Li, Wenhua

2013-01-01

Highlights: • Simplified model for tube-fin gas cooler for CO 2 refrigeration system was presented and validated. • Several parameters were investigated using 1st law and 2nd law in component and system level. • Practical guidelines of optimum for tube-fin gas cooler and intercooler were proposed. - Abstract: Energy-based 1st law and exergy-based 2nd law are both employed in the paper to assess the optimal design of gas cooler and intercooler for two-stage CO 2 refrigeration system. A simplified mathematical model of the air-cooled coil is presented and validated against experimental data with good accuracy. The optimum circuit length under the influence of frontal air velocity and deep rows is investigated first. Thereafter, designed coil with optimum circuit length is further evaluated within the two-stage refrigeration system. It is found out the optimum point using 1st law does not coincide with the point using 2nd law in isolated component and the simulation results from isolated component by 2nd law are closer to system analysis. Results show optimum circuit length is much bigger for gas cooler than intercooler and the influence on the length from variation of frontal air velocity and deep rows may be neglected. There does exist optimum frontal air velocity which will decrease with more number of deep rows

Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

Science.gov (United States)

Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

2016-08-01

This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

Attainability and minimum energy of single-stage membrane and membrane/distillation hybrid processes

KAUST Repository

Alshehri, Ali

2014-12-01

As an energy-efficient separation method, membrane technology has attracted more and more attentions in many challenging separation processes. The attainability and the energy consumption of a membrane process are the two basic fundamental questions that need to be answered. This report aims to use process simulations to find: (1) at what conditions a single-stage membrane process can meet the separation task that is defined by product purity and recovery ratio and (2) what are the most important parameters that determine the energy consumption. To perform a certain separation task, it was found that both membrane selectivity and pressure ratio exhibit a minimum value that is defined only by product purity and recovery ratio. The membrane/distillation hybrid system was used to study the energy consumption. A shortcut method was developed to calculate the minimum practical separation energy (MPSE) of the membrane process and the distillation process. It was found that the MPSE of the hybrid system is only determined by the membrane selectivity and the applied transmembrane pressure ratio in three stages. At the first stage when selectivity is low, the membrane process is not competitive to the distillation process. Adding a membrane unit to a distillation tower will not help in reducing energy. At the second medium selectivity stage, the membrane/distillation hybrid system can help reduce the energy consumption, and the higher the membrane selectivity, the lower is the energy. The energy conservation is further improved as pressure ratio increases. At the third stage when both selectivity and pressure ratio are high, the hybrid system will change to a single-stage membrane unit and this change will cause significant reduction in energy consumption. The energy at this stage keeps decreasing with selectivity at slow rate, but slightly increases with pressure ratio. Overall, the higher the membrane selectivity, the more the energy is saved. Therefore, the two

Attainability and minimum energy of multiple-stage cascade membrane Systems

KAUST Repository

Alshehri, Ali

2015-08-12

Process design and simulation of multi-stage membrane systems have been widely studied in many gas separation systems. However, general guidelines have not been developed yet for the attainability and the minimum energy consumption of a multi-stage membrane system. Such information is important for conceptual process design and thus it is the topic of this work. Using a well-mixed membrane model, it was determined that the attainability curve of multi-stage systems is defined by the pressure ratio and membrane selectivity. Using the constant recycle ratio scheme, the recycle ratio can shift the attainability behavior between single-stage and multi-stage membrane systems. When the recycle ratio is zero, all of the multi-stage membrane processes will decay to a single-stage membrane process. When the recycle ratio approaches infinity, the required selectivity and pressure ratio reach their absolute minimum values, which have a simple relationship with that of a single-stage membrane process, as follows: View the MathML sourceSn=S1, View the MathML sourceγn=γ1, where n is the number of stages. The minimum energy consumption of a multi-stage membrane process is primarily determined by the membrane selectivity and recycle ratio. A low recycle ratio can significantly reduce the required membrane selectivity without substantial energy penalty. The energy envelope curve can provide a guideline from an energy perspective to determine the minimum required membrane selectivity in membrane process designs to compete with conventional separation processes, such as distillation.

Temperature-phased anaerobic digestion of food waste: A comparison with single-stage digestions based on performance and energy balance.

Science.gov (United States)

Xiao, Benyi; Qin, Yu; Zhang, Wenzhe; Wu, Jing; Qiang, Hong; Liu, Junxin; Li, Yu-You

2018-02-01

The temperature-phased anaerobic digestion (TPAD) of food waste was studied for the purpose of comparing with single-stage mesophilic and thermophilic anaerobic digestion. The biogas and methane yields in the TPAD during the steady period were 0.759 ± 0.115 L/g added VS and 0.454 ± 0.201 L/g added VS, which were lower than those in the two single-stage anaerobic digestion. The improper sludge retention time may be the reason for the lower biogas and methane production in TPAD. The removal of volatile solids in the TPAD was 78.55 ± 4.59% and the lowest among the three anaerobic digestion processes. The reaction ratios of the four anaerobic digestion steps in the TPAD were all lower than those in the two single-stage anaerobic digestion. The energy conversion efficiency of the degraded substrate in the TPAD was similar with those in single-stage mesophilic and thermophilic anaerobic digestion systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrodeoxygenation of oils from cellulose in single and two-stage hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Rocha, J.D.; Snape, C.E. [Strathclyde Univ., Glasgow (United Kingdom); Luengo, C.A. [Universidade Estadual de Campinas, SP (Brazil). Dept. de Fisica Aplicada

1996-09-01

To investigate the removal of oxygen (hydrodeoxygenation) during the hydropyrolysis of cellulose, single and two-stage experiments on pure cellulose have been carried out using hydrogen pressures up to 10 MPa and temperatures over the range 300-520{sup o}C. Carbon, oxygen and aromaticity balances have been determined from the product yields and compositions. For the two-stage tests, the primary oils were passed through a bed of commercial Ni/Mo {gamma}-alumina-supported catalyst (Criterion 424, presulphided) at 400{sup o}C. Raising the hydrogen pressure from atmospheric to 10 MPa increased the carbon conversion by 10 mole % which was roughly equally divided between the oil and hydrocarbon gases. The oxygen content of the primary oil was reduced by over 10% to below 20% w/w. The addition of a dispersed iron sulphide catalyst further increased the oil yield at 10 MPa and reduces the oxygen content of the oil by a further 10%. The effect of hydrogen pressure on oil yields was most pronounced at low flow rates where it is beneficial in helping to overcome diffusional resistances. Unlike the dispersed iron sulphide in the first stage, the use of the Ni-Mo catalyst in the second stage reduced both the oxygen content and aromaticity of the oils. (Author)

Computer simulations of a single-laser double-gas-jet wakefield accelerator concept

Directory of Open Access Journals (Sweden)

R. G. Hemker

2002-04-01

Full Text Available We report in this paper on full scale 2D particle-in-cell simulations investigating laser wakefield acceleration. First we describe our findings of electron beam generation by a laser propagating through a single gas jet. Using realistic parameters which are relevant for the experimental setup in our laboratory we find that the electron beam resulting after the propagation of a 0.8 μm, 50 fs laser through a 1.5 mm gas jet has properties that would make it useful for further acceleration. Our simulations show that the electron beam is generated when the laser exits the gas jet, and the properties of the generated beam, especially its energy, depend only weakly on most properties of the gas jet. We therefore propose to use the first gas jet as a plasma cathode and then use a second gas jet placed immediately behind the first to provide additional acceleration. Our simulations of this proposed setup indicate the feasibility of this idea and also suggest ways to optimize the quality of the resulting beam.

Competition on the British natural gas market - development and mechanisms, and effects on the British gas industry

International Nuclear Information System (INIS)

Millgramm, C.

1996-01-01

The development of the British gas industry shows that structural changes at one industrial stage may have effects on the other stages and that competition at one stage (commercial stage) may be limited by the way the other stages are structured. The conditions of regulation in the gas industry, the development at its different stages, and its present structure are described. The effects of commercial restructuring on gas exploration and gas lifting, gas transport and gas storage are analyzed. (orig./UA) [de

Genomic Prediction of Single Crosses in the Early Stages of a Maize Hybrid Breeding Pipeline

Directory of Open Access Journals (Sweden)

Dnyaneshwar C. Kadam

2016-11-01

Full Text Available Prediction of single-cross performance has been a major goal of plant breeders since the beginning of hybrid breeding. Recently, genomic prediction has shown to be a promising approach, but only limited studies have examined the accuracy of predicting single-cross performance. Moreover, no studies have examined the potential of predicting single crosses among random inbreds derived from a series of biparental families, which resembles the structure of germplasm comprising the initial stages of a hybrid maize breeding pipeline. The main objectives of this study were to evaluate the potential of genomic prediction for identifying superior single crosses early in the hybrid breeding pipeline and optimize its application. To accomplish these objectives, we designed and analyzed a novel population of single crosses representing the Iowa Stiff Stalk synthetic/non-Stiff Stalk heterotic pattern commonly used in the development of North American commercial maize hybrids. The performance of single crosses was predicted using parental combining ability and covariance among single crosses. Prediction accuracies were estimated using cross-validation and ranged from 0.28 to 0.77 for grain yield, 0.53 to 0.91 for plant height, and 0.49 to 0.94 for staygreen, depending on the number of tested parents of the single cross and genomic prediction method used. The genomic estimated general and specific combining abilities showed an advantage over genomic covariances among single crosses when one or both parents of the single cross were untested. Overall, our results suggest that genomic prediction of single crosses in the early stages of a hybrid breeding pipeline holds great potential to redesign hybrid breeding and increase its efficiency.

A two-stage biological gas to liquid transfer process to convert carbon dioxide into bioplastic

KAUST Repository

Al Rowaihi, Israa

2018-03-06

The fermentation of carbon dioxide (CO2) with hydrogen (H2) uses available low-cost gases to synthesis acetic acid. Here, we present a two-stage biological process that allows the gas to liquid transfer (Bio-GTL) of CO2 into the biopolymer polyhydroxybutyrate (PHB). Using the same medium in both stages, first, acetic acid is produced (3.2 g L−1) by Acetobacterium woodii from 5.2 L gas-mixture of CO2:H2 (15:85 v/v) under elevated pressure (≥2.0 bar) to increase H2-solubility in water. Second, acetic acid is converted to PHB (3 g L−1 acetate into 0.5 g L−1 PHB) by Ralstonia eutropha H16. The efficiencies and space-time yields were evaluated, and our data show the conversion of CO2 into PHB with a 33.3% microbial cell content (percentage of the ratio of PHB concentration to cell concentration) after 217 h. Collectively, our results provide a resourceful platform for future optimization and commercialization of a Bio-GTL for PHB production.

Performance of the rebuilt SUERC single-stage accelerator mass spectrometer

Science.gov (United States)

Shanks, Richard P.; Ascough, Philippa L.; Dougans, Andrew; Gallacher, Paul; Gulliver, Pauline; Rood, Dylan H.; Xu, Sheng; Freeman, Stewart P. H. T.

2015-10-01

The SUERC bipolar single-stage accelerator mass spectrometer (SSAMS) has been dismantled and rebuilt to accommodate an additional rotatable pre-accelerator electrostatic spherical analyser (ESA) and a second ion source injector. This is for the attachment of an experimental positive-ion electron cyclotron resonance (ECR) ion source in addition to a Cs-sputter source. The ESA significantly suppresses oxygen interference to radiocarbon detection, and remaining measurement interference is now thought to be from 13C injected as 13CH molecule scattering off the plates of a second original pre-detector ESA.

A two-phase inspection model for a single component system with three-stage degradation

International Nuclear Information System (INIS)

Wang, Huiying; Wang, Wenbin; Peng, Rui

2017-01-01

This paper presents a two-phase inspection schedule and an age-based replacement policy for a single plant item contingent on a three-stage degradation process. The two phase inspection schedule can be observed in practice. The three stages are defined as the normal working stage, low-grade defective stage and critical defective stage. When an inspection detects that an item is in the low-grade defective stage, we may delay the preventive replacement action if the time to the age-based replacement is less than or equal to a threshold level. However, if it is above this threshold level, the item will be replaced immediately. If the item is found in the critical defective stage, it is replaced immediately. A hybrid bee colony algorithm is developed to find the optimal solution for the proposed model which has multiple decision variables. A numerical example is conducted to show the efficiency of this algorithm, and simulations are conducted to verify the correctness of the model. - Highlights: • A two-phase inspection model is studied. • The failure process has three stages. • The delayed replacement is considered.

Study of gas production from shale reservoirs with multi-stage hydraulic fracturing horizontal well considering multiple transport mechanisms

Science.gov (United States)

Wei, Mingzhen; Liu, Hong

2018-01-01

Development of unconventional shale gas reservoirs (SGRs) has been boosted by the advancements in two key technologies: horizontal drilling and multi-stage hydraulic fracturing. A large number of multi-stage fractured horizontal wells (MsFHW) have been drilled to enhance reservoir production performance. Gas flow in SGRs is a multi-mechanism process, including: desorption, diffusion, and non-Darcy flow. The productivity of the SGRs with MsFHW is influenced by both reservoir conditions and hydraulic fracture properties. However, rare simulation work has been conducted for multi-stage hydraulic fractured SGRs. Most of them use well testing methods, which have too many unrealistic simplifications and assumptions. Also, no systematical work has been conducted considering all reasonable transport mechanisms. And there are very few works on sensitivity studies of uncertain parameters using real parameter ranges. Hence, a detailed and systematic study of reservoir simulation with MsFHW is still necessary. In this paper, a dual porosity model was constructed to estimate the effect of parameters on shale gas production with MsFHW. The simulation model was verified with the available field data from the Barnett Shale. The following mechanisms have been considered in this model: viscous flow, slip flow, Knudsen diffusion, and gas desorption. Langmuir isotherm was used to simulate the gas desorption process. Sensitivity analysis on SGRs’ production performance with MsFHW has been conducted. Parameters influencing shale gas production were classified into two categories: reservoir parameters including matrix permeability, matrix porosity; and hydraulic fracture parameters including hydraulic fracture spacing, and fracture half-length. Typical ranges of matrix parameters have been reviewed. Sensitivity analysis have been conducted to analyze the effect of the above factors on the production performance of SGRs. Through comparison, it can be found that hydraulic fracture

Investigation of Advanced Propellants to Enable Single Stage to Orbit Launch Vehicles

Science.gov (United States)

2006-10-30

ERS-PAS-2006-205) 13. SUPPLEMENTARY NOTES Graduate work for California State University, Fresno 14. ABSTRACT Single-Stage-To-Orbit ( SSTO ...and maintained. Despite well-funded development efforts, no SSTO vehicles have been fielded to date. Existing chemical rocket and vehicle...technologies do not enable feasible SSTO designs. In the future, new propellants with advanced properties could enable SSTO launch vehicles. A parametric

Single-stage soft tissue reconstruction and orbital fracture repair for complex facial injuries.

Science.gov (United States)

Wu, Peng Sen; Matoo, Reshvin; Sun, Hong; Song, Li Yuan; Kikkawa, Don O; Lu, Wei

2017-02-01

Orbital fractures with open periorbital wounds cause significant morbidity. Timing of debridement with fracture repair and soft tissue reconstruction is controversial. This study focuses on the efficacy of early single-stage repair in combined bony and soft tissue injuries. Retrospective review. Twenty-three patients with combined open soft tissue wounds and orbital fractures were studied for single-stage orbital reconstruction and periorbital soft tissue repair. Inclusion criteria were open soft tissue wounds with clinical and radiographic evidence of orbital fractures and repair performed within 48 h after injury. Surgical complications and reconstructive outcomes were assessed over 6 months. The main outcome measures were enophthalmos, pre- and post-CT imaging of orbits, scar evaluation, presence of diplopia, and eyelid position. Enophthalmos was corrected in 16/19 cases and improved in 3/19 cases. 3D reconstruction of CT images showed markedly improved orbital alignment with objective measurements of the optic foramen to cornea distance (mm) in reconstructed orbits relative to intact orbits of 0.66, 95% confidence interval [CI] (lower 0.33, upper 0.99) mm. The mean baseline of Stony Brook Scar Evaluation Scale was 0.6, 95%CI (0.30-0.92), and for 6 months, the mean score was 3.4, 95%CI (3.05-3.73). Residual diplopia in secondary gazes was present in two patients; one patient had ectropion. Complications included one case of local wound infection. An early single-stage repair of combined soft tissue and orbital fractures yields satisfactory functional and aesthetic outcomes. Complications are low and likely related to trauma severity. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Strategies of enterprises facing european natural gas market

International Nuclear Information System (INIS)

Chevalier, J.M.

1992-01-01

The growing demand for natural gas in Europe is taking place within a gradual process of deregulation aiming to achieve a single energy market. Gas industry's traditional structure and behaviour are facing new forms of competition. Gas producers might be willing to capture a greater share of downstream profits while large users are interested in securing their supply at the cheapest cost. In addition, new comers could appear at all stages of the industry, that are becoming contestable markets. Challengers and defenders will probably induce important changes in industry's present structure. 11 refs., 1 fig., 3 tabs

Multiple kernel learning using single stage function approximation for binary classification problems

Science.gov (United States)

Shiju, S.; Sumitra, S.

2017-12-01

In this paper, the multiple kernel learning (MKL) is formulated as a supervised classification problem. We dealt with binary classification data and hence the data modelling problem involves the computation of two decision boundaries of which one related with that of kernel learning and the other with that of input data. In our approach, they are found with the aid of a single cost function by constructing a global reproducing kernel Hilbert space (RKHS) as the direct sum of the RKHSs corresponding to the decision boundaries of kernel learning and input data and searching that function from the global RKHS, which can be represented as the direct sum of the decision boundaries under consideration. In our experimental analysis, the proposed model had shown superior performance in comparison with that of existing two stage function approximation formulation of MKL, where the decision functions of kernel learning and input data are found separately using two different cost functions. This is due to the fact that single stage representation helps the knowledge transfer between the computation procedures for finding the decision boundaries of kernel learning and input data, which inturn boosts the generalisation capacity of the model.

Flame Motion In Gas Turbine Burner From Averages Of Single-Pulse Flame Fronts

Energy Technology Data Exchange (ETDEWEB)

Tylli, N.; Hubschmid, W.; Inauen, A.; Bombach, R.; Schenker, S.; Guethe, F. [Alstom (Switzerland); Haffner, K. [Alstom (Switzerland)

2005-03-01

Thermo acoustic instabilities of a gas turbine burner were investigated by flame front localization from measured OH laser-induced fluorescence single pulse signals. The average position of the flame was obtained from the superposition of the single pulse flame fronts at constant phase of the dominant acoustic oscillation. One observes that the flame position varies periodically with the phase angle of the dominant acoustic oscillation. (author)

Prognosis, prospecting and development of gas fields in the far north of Siberia - as a single methodological approach to an optimal development of the territorial resources; Prevision, prospection et developpement des champs de gaz naturel du grand nord Siberien - approche methodologique unique pour un developpement optimal des ressources du territoire

Energy Technology Data Exchange (ETDEWEB)

Remizov, V.V.; Dmitrievsky, A.N.; Ermilov, O.M.; Neelov, Y.V.; Chugunov, L.S.; Gurari, F.G.; Goldin, S.V.; Karagodin, Y.N. [OJSC Gaprom, Russian Academy of Sciences (Russian Federation)

2000-07-01

This presentation realizes a systems approach to the study of the oil and gas complex of the Far North of Siberia as a single sophisticated system starting from prognosis and prospecting of fields to their development at different stages of operation. This paper shows for the first time the whole complex of studies, including the methodology of systems studies of the structure, evolution and genesis of oil and gas reservoirs, the model of geologic structure and the evaluation of oil and gas resources, the technique of prospecting and surveys of oil and gas fields, techniques and methods of an effective system of prospecting and development, particularly at the stage of achieving maximum and the onset of production decrease. (authors)

Comparison of feature and classifier algorithms for online automatic sleep staging based on a single EEG signal

NARCIS (Netherlands)

Radha, M.; Garcia Molina, G.; Poel, M.; Tononi, G.

2014-01-01

Automatic sleep staging on an online basis has recently emerged as a research topic motivated by fundamental sleep research. The aim of this paper is to find optimal signal processing methods and machine learning algorithms to achieve online sleep staging on the basis of a single EEG signal. The

DeepSleepNet: A Model for Automatic Sleep Stage Scoring Based on Raw Single-Channel EEG.

Science.gov (United States)

Supratak, Akara; Dong, Hao; Wu, Chao; Guo, Yike

2017-11-01

This paper proposes a deep learning model, named DeepSleepNet, for automatic sleep stage scoring based on raw single-channel EEG. Most of the existing methods rely on hand-engineered features, which require prior knowledge of sleep analysis. Only a few of them encode the temporal information, such as transition rules, which is important for identifying the next sleep stages, into the extracted features. In the proposed model, we utilize convolutional neural networks to extract time-invariant features, and bidirectional-long short-term memory to learn transition rules among sleep stages automatically from EEG epochs. We implement a two-step training algorithm to train our model efficiently. We evaluated our model using different single-channel EEGs (F4-EOG (left), Fpz-Cz, and Pz-Oz) from two public sleep data sets, that have different properties (e.g., sampling rate) and scoring standards (AASM and R&K). The results showed that our model achieved similar overall accuracy and macro F1-score (MASS: 86.2%-81.7, Sleep-EDF: 82.0%-76.9) compared with the state-of-the-art methods (MASS: 85.9%-80.5, Sleep-EDF: 78.9%-73.7) on both data sets. This demonstrated that, without changing the model architecture and the training algorithm, our model could automatically learn features for sleep stage scoring from different raw single-channel EEGs from different data sets without utilizing any hand-engineered features.

The resistive plate WELL detector as a single stage thick gaseous multiplier detector

Energy Technology Data Exchange (ETDEWEB)

Bressler, Shikma; Breskin, Amos; Moleri, Luca; Kumar, Ashwini; Pitt, Michael [Department of Particle Physics and Astrophysics, Weizmann Institute of Science (WIS) (Israel); Kudella, Simon [Institut fuer Experimentelle Kernphysik (IEKP), KIT (Germany)

2015-07-01

Gaseous Electron Multiplier (GEM) detector use high electric fields inside the h ole of a foil to achieve a high charge multiplication. As a thicker version of G EMs based on printed circuit board (PCB) structures, Thick Gaseous Electron Multiplier (THGEM) detectors combine the high gain of a GEM foil with the robustness, stability and low production costs of a PCB and allow a large quantity of applications that require the coverage of a large area at low cost and moderate spatial resolution. One application the Weizmann Institute of Science (WIS) develops as a member of the RD51 framework is the Resistive Plate WELL (RPWELL) detector. This single stage detector allows a very stable, discharge free operation at high gain (10{sup 5}). The single stage operation allows a low total height and make s the RPWELL a candidate for the Digital Hadronic Calorimeter (DHCAL) of the International Large Detector (ILD) at the International Linear Collider (ILC). The talk gives an insight into the way the RPWELL works and shows results from the last test beam.

A Single-Walled Carbon Nanotube Network Gas Sensing Device

Directory of Open Access Journals (Sweden)

I-Ju Teng

2011-08-01

Full Text Available The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD. The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3.

Numerical simulations of single and multi-staged injection of H2 in a supersonic scramjet combustor

Directory of Open Access Journals (Sweden)

L. Abu-Farah

2014-12-01

Full Text Available Computational fluid dynamics (CFD simulations of a single staged injection of H2 through a central wedge shaped strut and a multi-staged injection through wall injectors are carried out by using Ansys CFX-12 code. Unstructured tetrahedral grids for narrow channel and quarter geometries of the combustor are generated by using ICEM CFD. Steady three-dimensional (3D Reynolds-averaged Navier-stokes (RANS simulations are carried out in the case of no H2 injection and compared with the simulations of single staged pilot and/or main H2 injections and multistage injection. Shear stress transport (SST based on k-ω turbulent model is adopted. Flow field visualization (complex shock waves interactions and static pressure distribution along the wall of the combustor are predicted and compared with the experimental schlieren images and measured wall static pressures for validation. A good agreement is found between the CFD predicted results and the measured data. The narrow and quarter geometries of the combustor give similar results with very small differences. Multi-staged injections of H2 enhance the turbulent H2/air mixing by forming vortices and additional shock waves (bow shocks.

Clinical Outcomes and Risks of Single-stage Bilateral Unicompartmental Knee Arthroplasty via Oxford Phase III

Directory of Open Access Journals (Sweden)

Tong Ma

2015-01-01

Full Text Available Background: Osteoarthritis often affects the joint bilaterally, and the single-stage (SS unicompartmental knee arthroplasty (UKA is advantageous in terms of a single anesthesia administration, a short hospital stay, lower medical costs, and enhanced patient convenience. However, the complication risk of SS UKA continues to be debated. The aim of this article was to evaluate the clinical effectiveness, complications, and functional recovery of SS and two-stage (TS UKA. Methods: From January 2008 to December 2013, we compared a series of 36 SS UKA with 45 TS UKA for osteoarthritis. The mean age was 65.4 years (range: 55-75 years. The mean body mass index was 25.2 kg/m 2 (range: 22-29 kg/m 2 . The pre- and post-operative Oxford Knee Scores (OKSs, complications, operative times, tourniquet times, the amount of drainage, and hemoglobin (Hb were evaluated. The Chi-square test, Fisher′s exact test, and paired and grouped t-tests were used in this study. Results: The mean follow-up was 50 months. No complications of death, fat embolism, deep vein thrombosis, and prosthetic infection were reported. Patients who underwent SS UKA had a shorter cumulative anesthesia time (113.5 vs. 133.0 min, P 0.05. At the final follow-up, the mean OKS improved from 39.48 ± 5.69 to 18.83 ± 3.82 (P 0.05. Patients who underwent SS UKA had a faster recovery. Conclusions: The single-staged UKA offers the benefits of a single anesthesia administration, reduced total anesthetic time, decreased overall rehabilitation time, and absence of an increase in perioperative mortality or complications compared with the TS bilateral UKA.

Modeling condom-use stage of change in low-income, single, urban women.

Science.gov (United States)

Morrison-Beedy, Dianne; Carey, Michael P; Lewis, Brian P

2002-04-01

This study was undertaken to identify and test a model of the cognitive antecedents to condom use stage of change in low-income, single, urban women. A convenience sample of 537 women (M=30 years old) attending two urban primary health care settings in western New York State anonymously completed questionnaires based primarily on two leading social-cognitive models, the transtheoretical model and the information-motivation-behavioral skills model. We used structural equation modeling to examine the direct and indirect effects of HIV-related knowledge, social norms of discussing HIV risk and prevention, familiarity with HIV-infected persons, general readiness to change sexual behaviors, perceived vulnerability to HIV, and pros and cons of condom use on condom-use stage of change. The results indicated two models that differ by partner type. Condom-use stage of change in women with steady main partners was influenced most by social norms and the pros of condom use. Condom-use stage of change in women with "other" types (multiple, casual, or new) of sexual partners was influenced by HIV-related knowledge, general readiness to change sexual behaviors, and the pros of condom use. These findings suggest implications for developing gender-relevant HIV-prevention interventions. Copyright 2002 Wiley Periodicals, Inc.

Public consultation of 27 July 2017 no. 2017-012 relating to the creation of a single gas market area in France on 1 November 2018

International Nuclear Information System (INIS)

2017-01-01

This public consultation concerns the operational conditions for the creation of a single gas market area in France on 1 November 2018. It forms part of the road-map towards a single gas market area in France as defined by the CRE in 2012. In order to relieve the existing congestion between the GRTgaz network North and South zones and to enable the creation of a single market area common to GRTgaz and TIGF, the CRE adopted, in its deliberation of 7 May 2014, the investment configuration associating the reinforcement of the Val-de-Saone pipeline and the Gascogne-Midi project. These new infrastructures, developed by GRTgaz and TIGF, have been designed to enable the creation of a single zone at an optimised cost. Consequently, in certain network configurations of use, residual congestions could exceptionally occur. This public consultation proposes the contractual mechanisms planned at this stage to relieve this congestion so as to ensure the availability of firm capacity. In order to define the most relevant mechanisms, the TSOs have studied the occurrence of residual congestion and the solutions that could be implemented to remedy them in the Concertation Gas process since September 2016. At the end of this work, the TSOs submitted a joint proposal to the CRE, which is annexed to this public consultation. In addition, pending the commissioning of new works, and while the 2016-2017 winter was marked by a South-East congestion that resulted in constraints in the nomination of certain players, this public consultation also focuses on the solutions studied by the TSOs in the event that this congestion occurs again in the winter of 2017-2018, as well as the changes in the price of imbalances

Armature formation in a railgun using a two-stage light-gas gun injector

International Nuclear Information System (INIS)

Hawke, R.S.; Susoeff, A.R.; Asay, J.R.; Hall, C.A.; Konrad, C.H.; Hickman, R.J.; Sauve, J.L.

1989-01-01

During the past decade several research groups have tried to achieve reliable acceleration of projectiles to velocities in excess of 8 km/s by using a railgun. All attempts have met with difficulties. However, in the past four years the researchers have come to agree on the nature and causes of the difficulties. The consensus is that the hot plasma armature - used to commutate across the rails and to accelerate the projectile - causes ablation of the barrel wall; this ablation ultimately results in parasitic secondary arc formation through armature separation and/or restrike. The subsequence deprivation of current to the propulsion armature results in a limit to the achievable projectile velocity. Methods of mitigating the process are under study. One method uses a two-stage light-gas gun as a preaccelerator/injector to the railgun. The gas gun serves a double purpose: It quickly accelerates the projectile to a high velocity, and it fills the barrel behind the propulsive armature with insulating gas. While this approach is expected to improve railgun performance, it also requires development of techniques to form the propulsive armature behind the projectile in the high-velocity, high-pressure gas stream. This paper briefly summarizes the problems encountered in attempts to achieve hypervelocities with a railgun. Included is a description of the phenomenology and details of joint Sandia National Laboratories, Albuquerque/Lawrence Livermore National Laboratory (SNLA/LNLL) work at SNLA on a method for forming the needed plasma armature

Vyrmethane. Progress report stage 5. In situ production of methane gas from peat

Energy Technology Data Exchange (ETDEWEB)

Martinell, R

1982-12-01

The Vyrmethane process means that bog water containing methane gas is circulated in a closed system and degassed. By this procedure the microbiological activity in the bog stimulates and new methane is produced and dissolved in the water, which circulates to a degassing station. From the degassing station the methane gas can be used for different purposes and the degassed water is infiltrated back in the peat bog. The degradation process is described by McCarty (Stanford 1964). According to this description all COD (Chemical Oxygen Demand) is supposed to be converted to methane. The Vyrmethane method does not reach this ideal result. Consequently the produced gas also includes carbon dioxide. The running cost for the process is mainly depending on the water circulation e.g. the demand of energy for the pumps. Consequently the result is propotional to the methane, which can be degassed from the circulated water. The results reached, so far, indicate that one added unit of mechanical energy is giving five units of heat energy in the form of methane gas. Better results are in prospect. This report, which is a following up of the pilot plants started up after 1978, is discussing the technical and economical conditions for the process. Consequently it is suggested that a number of full-scale prototype plants are built, studied further and that preparations are made for a demonstration stage including about 200 plants with geographical spreading out.

Implementation of Exhaust Gas Recirculation for Double Stage Waste Heat Recovery System on Large Container Vessel

DEFF Research Database (Denmark)

Andreasen, Morten; Marissal, Matthieu; Sørensen, Kim

2014-01-01

Concerned to push ships to have a lower impact on the environment, the International Maritime Organization are implementing stricter regulation of NOx and SOx emissions, called Tier III, within emission control areas (ECAs). Waste Heat Recovery Systems (WHRS) on container ships consist...... of recovering some of the waste heat from the exhaust gas. This heat is converted into electrical energy used on-board instead of using auxiliary engines. Exhaust Gas Recirculation (EGR) systems, are recirculating a part of the exhaust gas through the engine combustion chamber to reduce emissions. WHRS combined...... with EGR is a potential way to improve system efficiency while reducing emissions. This paper investigates the feasibility of combining the two systems. EGR dilutes the fuel, lowering the combustion temperature and thereby the formation of NOx, to reach Tier III limitation. A double stage WHRS is set up...

Single stage three level grid interactive MPPT inverter for PV systems

International Nuclear Information System (INIS)

Ozdemir, Saban; Altin, Necmi; Sefa, Ibrahim

2014-01-01

Highlights: • A three phase three-level NPC inverter for grid interactive PV systems is proposed. • A novel MPPT algorithm is introduced for single stage systems. • The proposed algorithm is robust with respect to parameter variations of PV system. • THD level is measured as 3.45% and it meets the international standards (<5%). • Total system efficiency is measured as 93.08%. - Abstract: In this study, three-phase, single stage neutral point clamped grid interactive inverter is designed and implemented. The reference current of the voltage source inverter is determined by maximum power point tracking sub-program in order to obtain maximum power from photovoltaic modules instantaneously. Proposed control is realized via TMS320F28335 32-bit floating point processor. The modified incremental conductance method is applied for maximum power point tracking; the PI regulator is used to control the inverter output current shape and level. Galvanic isolation is provided by a line frequency transformer that matches inverter output voltage to the grid voltage level and prevents DC current injection into the grid. Experimental results show that the designed inverter imports energy to the grid with unity power factor, total harmonic distortion level is 3.45% and this value is in the limits of the international standards. In addition, the total efficiency of the system is measured as 93.08%. The proposed system gets the maximum power from photovoltaic module and dispatches into the grid without using additional DC/DC converter

Conceptual design of helium gas turbine for MHTGR-GT

International Nuclear Information System (INIS)

Matsuo, E.; Tsutsumi, M.; Ogata, K.; Nomura, S.

1996-01-01

Conceptual designs of the direct-cycle helium gas turbine for a practical unit (450 MWt) and an experimental unit (1200kWt) of MHTGR were conducted and the results as shown below were obtained. The power conversion vessel for this practical unit can further be downsized to an outside diameter of 7.4m and a height of 22m as compared with the conventional design examples. Comparison of the conceptual designs of helium gas turbines using single-shaft type employing the axial-flow compressor and twin-shaft type employing the centrifugal compressor shows that the former provides advantages in terms of structure and control designs whereas the latter offers a higher efficiency. In order to determine which of them should be selected, a further study to investigate various aspects of safety features and startup characteristics will be needed. Either of the two types can provide a cycle efficiency of 46 to 48%. The third mode natural frequencies of the twin-shart type's low-pressure rotational shaft and the single shaft type are below the designed rotational speed, but their vibrational controls are made available using the magnetic bearing system. Elevation of the natural frequency for the twin-shaft type would be possible by altering the arrangements of its shafting configuration. As compared with the earlier conceptual designs, the overall systems configuration can be made simpler and more compact; five stages of turbines for the single-shaft type and seven stages of turbines for the twin-shaft type employing one shaft for the low-pressure compressor and the power turbine and; 26 stages of compressors for the axial-flow type with the single shaft system and five stages of compressors for the centrifugal type with the twin-shaft system. 9 refs, 12 figs, 4 tabs

Propulsion requirements for reusable single-stage-to-orbit rocket vehicles

Science.gov (United States)

Stanley, Douglas O.; Engelund, Walter C.; Lepsch, Roger

1994-05-01

The conceptual design of a single-stage-to-orbit (SSTO) vehicle using a wide variety of evolutionary technologies has recently been completed as a part of NASA's Advanced Manned Launch System (AMLS) study. The employment of new propulsion system technologies is critical to the design of a reasonably sized, operationally efficient SSTO vehicle. This paper presents the propulsion system requirements identified for this near-term AMLS SSTO vehicle. Sensitivities of the vehicle to changes in specific impulse and sea-level thrust-to-weight ratio are examined. The results of a variety of vehicle/propulsion system trades performed on the near-term AMLS SSTO vehicle are also presented.

Towards radiocarbon dating of single foraminifera with a gas ion source

Science.gov (United States)

Wacker, L.; Lippold, J.; Molnár, M.; Schulz, H.

2013-01-01

Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO2 is liberated from 150 to 1150 μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 μg (50 μg C) typically gives a 12C- ion source current of 10-15 μA over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 μg Cibicides pseudoungerianus test at 14,030 ± 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

Towards radiocarbon dating of single foraminifera with a gas ion source

International Nuclear Information System (INIS)

Wacker, L.; Lippold, J.; Molnár, M.; Schulz, H.

2013-01-01

Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO 2 is liberated from 150 to 1150 μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO 2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 μg (50 μg C) typically gives a 12 C − ion source current of 10–15 μA over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 μg Cibicides pseudoungerianus test at 14,030 ± 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

Towards radiocarbon dating of single foraminifera with a gas ion source

Energy Technology Data Exchange (ETDEWEB)

Wacker, L., E-mail: wacker@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Lippold, J. [Heidelberg Academy of Sciences, 69120 Heidelberg (Germany); Molnar, M. [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Institute of Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Schulz, H. [Institute for Geosciencies, University of Tuebingen, 72076 Tuebingen (Germany)

2013-01-15

Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 {mu}g for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO{sub 2} is liberated from 150 to 1150 {mu}g of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO{sub 2} is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 {mu}g (50 {mu}g C) typically gives a {sup 12}C{sup -} ion source current of 10-15 {mu}A over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 {mu}g Cibicides pseudoungerianus test at 14,030 {+-} 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

Single Stage Contactor Testing Of The Next Generation Solvent Blend

Energy Technology Data Exchange (ETDEWEB)

Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

2014-01-06

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

Single-Stage Step up/down Driver for Permanent-Magnet Synchronous Machines

Science.gov (United States)

Chen, T. R.; Juan, Y. L.; Huang, C. Y.; Kuo, C. T.

2017-11-01

The two-stage circuit composed of a step up/down dc converter and a three-phase voltage source inverter is usually adopted as the electric vehicle’s motor driver. The conventional topology is more complicated. Additional power loss resulted from twice power conversion would also cause lower efficiency. A single-stage step up/down Permanent-Magnet Synchronous Motor driver for Brushless DC (BLDC) Motor is proposed in this study. The number components and circuit complexity are reduced. The low frequency six-step square-wave control is used to reduce the switching losses. In the proposed topology, only one active switch is gated with a high frequency PWM signal for adjusting the rotation speed. The rotor position signals are fed back to calculate the motor speed for digital close-loop control in a MCU. A 600W prototype circuit is constructed to drive a BLDC motor with rated speed 3000 rpm, and can control the speed of six sections.

Single Ion transient-IBIC analyses of semiconductor devices using a cryogenic temperature stage

International Nuclear Information System (INIS)

Laird, J.S.; Bardos, R.; Legge, G.J.F.; Jagadish, C.

1998-01-01

A new Transient - IBIC data acquisition and analysis system at MARC is described. A discussion on the need for single ion control and temperature control is also given. The recorded signal is used as the trigger for beam pulsing. The new cryostatic temperature control stage is introduced. Data is presented on line profiles across the edge of a Au-Si junction collected over the temperature range of 25-300K using a developed C-V and I-V variable temperature stage incorporating a liquid helium cryostat. It demonstrates the potential improvements in spatial resolution in materials of long lifetime by mapping on timing windows around the prompt charge component in the charge transient

Low-frequency noise characterization of single CuO nanowire gas sensor devices

NARCIS (Netherlands)

Steinhauer, S.; Köck, A.; Gspan, C.; Grogger, W.; Vandamme, L.K.J.; Pogany, D.

2015-01-01

Low-frequency noise properties of single CuO nanowire devices were investigated under gas sensor operation conditions in dry and humid synthetic air at 350¿°C. A 1/f noise spectrum was found with the normalized power spectral density of current fluctuations typically a factor of 2 higher for humid

Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

Energy Technology Data Exchange (ETDEWEB)

Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong [Inha Univ., Incheon (Korea, Republic of)

2017-01-15

In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

International Nuclear Information System (INIS)

Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong

2017-01-01

In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

The new 6 MW gas turbine for the power generation; Die neue 6 MW Gasturbine fuer die Stromerzeugung

Energy Technology Data Exchange (ETDEWEB)

Blaswich, Michael; Theis, Sascha [MAN Diesel and Turbo SE, Oberhausen (Germany)

2012-07-01

MAN Diesel and Turbo SE (Oberhausen, Federal Republic of Germany) had developed a new gas turbine in the 6 MW class. This device is the founding stone for a family of gas turbines which at first cover the power range from 6 to 8 MW for the propulsion of pumps, compressors and electric devices. The two-shaft industrial gas turbine consists of a gas generator with an axial compressor with eleven levels, six external single combustion chambers, one two-step high-pressure turbine and a two-step power turbine. Beside the two-shaft industrial gas turbine, there exists a single-shaft industrial gas turbine for the power generation. The single-shaft industrial gas turbine consists of three turbine stages, a gas turbine compressor and combustion chamber being identical in construction to the two-shaft industrial gas turbine. The gas turbine package contains the gas turbine module as well as a filter module. The gas turbine was successfully tested. Further tests and the commissioning of the first customer's plant are planned for this year.

Single-stage-to-orbit: Meeting the challenge

Science.gov (United States)

Freeman, Delma C., Jr.; Talay, Theodore A.; Austin, Robert Eugene

1995-10-01

There has been and continues to be significant discussion about the viability of fully reusable, single-stage-to-orbit (SSTO) concepts for delivery of payloads to orbit. Often, these discussions have focused in detail on performance and technology requirements relating to the technical feasibility of the concept, with only broad generalizations on how the SSTO will achieve its economic goals of greatly reduced vehicle ground and flight operations costs. With the current industry and NASA Reusable Launch Vehicle Technology Program efforts underway to mature and demonstrate technologies leading to a viable commercial launch system that also satisfies national needs, achieving acceptable recurring costs becomes a significant challenge. This paper reviews the current status of the Reusable Launch Vehicle Technology Program including the DC-XA, X-33, and X-34 flight systems and associated technology programs. The paper also examines lessons learned from the recently completed DC-X reusable rocket demonstrator program. It examines how these technologies and flight systems address the technical and operability challenges of SSTO whose solutions are necessary to reduce costs. The paper also discusses the management and operational approaches that address the challenge of a new cost-effective, reusable launch vehicle system.

CFD simulations of compressed air two stage rotary Wankel expander – Parametric analysis

International Nuclear Information System (INIS)

Sadiq, Ghada A.; Tozer, Gavin; Al-Dadah, Raya; Mahmoud, Saad

2017-01-01

Highlights: • CFD ANSYS-Fluent 3D simulation of Wankel expander is developed. • Single and two-stage expander’s performance is compared. • Inlet and outlet ports shape and configurations are investigated. • Isentropic efficiency of two stage Wankel expander of 91% is achieved. - Abstract: A small scale volumetric Wankel expander is a powerful device for small-scale power generation in compressed air energy storage (CAES) systems and Organic Rankine cycles powered by different heat sources such as, biomass, low temperature geothermal, solar and waste heat leading to significant reduction in CO_2 emissions. Wankel expanders outperform other types of expander due to their ability to produce two power pulses per revolution per chamber additional to higher compactness, lower noise and vibration and lower cost. In this paper, a computational fluid dynamics (CFD) model was developed using ANSYS 16.2 to simulate the flow dynamics for a single and two stage Wankel expanders and to investigate the effect of port configurations, including size and spacing, on the expander’s power output and isentropic efficiency. Also, single-stage and two-stage expanders were analysed with different operating conditions. Single-stage 3D CFD results were compared to published work showing close agreement. The CFD modelling was used to investigate the performance of the rotary device using air as an ideal gas with various port diameters ranging from 15 mm to 50 mm; port spacing varying from 28 mm to 66 mm; different Wankel expander sizes (r = 48, e = 6.6, b = 32) mm and (r = 58, e = 8, b = 40) mm both as single-stage and as two-stage expanders with different configurations and various operating conditions. Results showed that the best Wankel expander design for a single-stage was (r = 48, e = 6.6, b = 32) mm, with the port diameters 20 mm and port spacing equal to 50 mm. Moreover, combining two Wankel expanders horizontally, with a larger one at front, produced 8.52 kW compared

Advances in single- and multi-stage Stirling-type pulse tube cryocoolers for space applications in NLIP/SITP/CAS

Science.gov (United States)

Dang, Haizheng; Tan, Jun; Zha, Rui; Li, Jiaqi; Zhang, Lei; Zhao, Yibo; Gao, Zhiqian; Bao, Dingli; Li, Ning; Zhang, Tao; Zhao, Yongjiang; Zhao, Bangjian

2017-12-01

This paper presents a review of recent advances in single- and multi-stage Stirling-type pulse tube cryocoolers (SPTCs) for space applications developed at the National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences (NLIP/SITP/CAS). A variety of single-stage SPTCs operating at 25-150 K have been developed, including several mid-sized ones operating at 80-110 K. Significant progress has been achieved in coolers operating at 30-40 K which use common stainless steel meshes as regenerator matrices. Another important advance is the micro SPTCs with an overall mass of 300-800 g operating at high frequencies varying from 100 Hz to 400 Hz. The main purpose of developing two-stage SPTCs is to simultaneously acquire cooling capacities at both stages, obviating the need for auxiliary precooling in various applications. The three-stage SPTCs are developed mainly for applications at around 10 K, which are also used for precooling the J-T coolers to achieve further lower temperatures. The four-stage SPTCs are developed to directly achieve the liquid helium temperature for cooling space low-Tc superconducting devices and for the deep space exploration as well. Several typical development programs are described and an overview of the cooler performances is presented.

Three mechanisms model of shale gas in real state transport through a single nanopore

Science.gov (United States)

Li, Dongdong; Zhang, Yanyu; Sun, Xiaofei; Li, Peng; Zhao, Fengkai

2018-02-01

At present, the apparent permeability models of shale gas consider only the viscous flow and Knudsen diffusion of free gas, but do not take into account the influence of surface diffusion. Moreover, it is assumed that shale gas is in ideal state. In this paper, shale gas is assumed in real state, a new apparent permeability model for shale gas transport through a single nanopore is developed that captures many important migration mechanisms, such as viscous flow and Knudsen diffusion of free gas, surface diffusion of adsorbed gas. According to experimental data, the accuracy of apparent permeability model was verified. What’s more, the effects of pressure and pore radius on apparent permeability, and the effects on the permeability fraction of viscous flow, Knudsen diffusion and surface diffusion were analysed, separately. Finally, the results indicate that the error of the developed model in this paper was 3.02%, which is less than the existing models. Pressure and pore radius seriously affect the apparent permeability of shale gas. When the pore radius is small or pressure is low, the surface diffusion cannot be ignored. When the pressure and the pore radius is big, the viscous flow occupies the main position.

Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study.

Science.gov (United States)

Romero-Hermida, M I; Romero-Enrique, J M; Morales-Flórez, V; Esquivias, L

2016-08-21

Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N2, CO2, and O2, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO2 adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO2 adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO2 adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO2 adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO2 concentrations and low temperatures, the CO2 adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.

Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

International Nuclear Information System (INIS)

Romero-Hermida, M. I.; Romero-Enrique, J. M.; Morales-Flórez, V.; Esquivias, L.

2016-01-01

Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N 2 , CO 2 , and O 2 , emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO 2 adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO 2 adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO 2 adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO 2 adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO 2 concentrations and low temperatures, the CO 2 adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.

Arrayed architectures for multi-stage Si-micromachined high-flow Knudsen pumps

International Nuclear Information System (INIS)

Qin, Yutao; An, Seungdo; Gianchandani, Yogesh B

2015-01-01

This paper reports an evaluation and a comparison of two architectures for implementing Si-micromachined high-flow Knudsen pumps. Knudsen pumps, which operate on the principle of thermal transpiration, have been shown to have great promise for micro-scale gas phase fluidic systems such as micro gas chromatographs. Simultaneously achieving both a high flow rate and adequate blocking pressure has been a persistent challenge, which is addressed in this work by combining multiple pumps in series and addressing the resulting challenges in thermal management. The basic building block is a Si-micromachined pump with  ≈100 000 parallel channels in a 4 mm  ×  6 mm footprint. In the primary approach, multiple pump stages are stacked vertically with interleaved Si-micromachined spacers. A stacked 4-stage Knudsen pump has a form factor of 10 mm  ×  8 mm  ×  6 mm. In an alternate approach, multiple stages are arranged in a planar array. The experimental results demonstrate multiplication of the output pressure head with the number of stages, while the flow rate is maintained. For example, a stacked 4-stage Knudsen pump with 8 W power operated at atmospheric pressure provided a blocking pressure of 0.255 kPa, which was 3.6  ×  of that provided by a single-stage pump with 2 W power; while both provided a  ≈  30 sccm maximum flow rate. The performance can be customized for practical applications such as micro gas chromatography. (paper)

NASA Glenn's Single-Stage Axial Compressor Facility Upgraded

Science.gov (United States)

Brokopp, Richard A.

2004-01-01

NASA Glenn Research Center's Single-Stage Axial Compressor Facility was upgraded in fiscal year 2003 to expand and improve its research capabilities for testing high-speed fans and compressors. The old 3000-hp drive motor and gearbox were removed and replaced with a refurbished 7000-hp drive motor and gearbox, with a maximum output speed of 21,240 rpm. The higher horsepower rating permits testing of fans and compressors with higher pressure ratio or higher flow. A new inline torquemeter was installed to provide an alternate measurement of fan and compressor efficiency, along with the standard pressure and temperature measurements. A refurbished compressor bearing housing was also installed with bidirectional rotation capability, so that a variety of existing hardware could be tested. Four new lubrication modules with backup capability were installed for the motor, gearbox, torquemeter, and compressor bearing housing, so that in case the primary pump fails, the backup will prevent damage to the rotating hardware. The combustion air supply line for the facility inlet air system was activated to provide dry air for repeatable inlet conditions. New flow conditioning hardware was installed in the facility inlet plenum tank, which greatly reduced the inlet turbulence. The new inlet can also be easily modified to accommodate 20- or 22-in.-diameter fans and compressors, so a variety of existing hardware from other facilities (such as Glenn's 9- by 15-Foot Low-Speed Wind Tunnel) can be tested in the Single-Stage Axial Compressor Facility. An exhaust line was also installed to provide bleed capability to remove the inlet boundary layer. To improve the operation and control of the facility, a new programmable logic controller (PLC) was installed to upgrade from hardwired relay logic to software logic. The PLC also enabled the usage of human-machine interface software to allow for easier operation of the facility and easier reconfiguration of the facility controls when

Study on air ingress during an early stage of a primary-pipe rupture accident of a high-temperature gas-cooled reactor

International Nuclear Information System (INIS)

Hishida, M.; Takeda, T.

1991-01-01

A primary-pipe rupture accident is one of the design-based accidents of the HTTR. As the first step of our final goal of predicting the multicomponent gas flow in a reactor during the early stages of the accident, the present paper aims at studying experimentally and analytically, the basic features of air ingress and gas transportation by transient molecular diffusion and the transient natural convection of a two-component gas mixture. The present paper comprises two main parts. The first part deals with analytical and experimental studies on N 2 ingress (corresponding to air ingress) and gas transportation by molecular diffusion and the one-dimensional natural convection of an He-N 2 two-component gas mixture in a reverse-U-shaped tube. Analytical and experimental results are discussed on the N 2 mole fraction change with time after the simulated pipe rupture and on the initation time of the natural circulation of pure N 2 . The second part deals with a preliminary simulation test of air ingress during the early stages of the accident. The test is performed with a very simple model of the reactor. The experimental results are discussed on the change in mole fraction of air with time and on the initiation time of the natural circulation of pure air. (orig.)

Effect of Single and Double Stage Chemically Treated Kenaf Fibers on Mechanical Properties of Polyvinyl Alcohol Film

Directory of Open Access Journals (Sweden)

Md Ershad Ali

2014-12-01

Full Text Available The physico-mechanical properties of lignocellulosic kenaf fiber reinforced polyvinyl alcohol (PVA biocomposite films were investigated. To improve the properties of the biocomposite, kenaf fibers were chemically treated separately in a single stage (with Cr2(SO4312(H2O and double stages (with CrSO4 and NaHCO3 to improve the adhesion and compatibility between the kenaf fiber and PVA matrix. PVA was reinforced with various compositions of chemically treated kenaf fiber by using a solution casting technique. Microstructural analyses and mechanical tests were subsequently conducted. Scanning electron microscopic analysis indicated that chemical treatment improved the uniformity distribution of kenaf fiber within the PVA matrix. FTIR and XRD analyses confirmed the presence of chromium on the fiber surface. The tensile strength of PVA reinforced with chemical treated kenaf fiber was found to be higher than those reinforced with untreated kenaf. The Young’s modulus, flexural strength, and flexural modulus increased with fiber loading for both untreated and treated kenaf fiber reinforced PVA films. The double stage treated kenaf fiber showed better mechanical properties and lower moisture uptake than the single stage treated kenaf fiber.

Single-stage three-phase AC to DC conversion with isolation and Bi-directional power flow

NARCIS (Netherlands)

Vermulst, B.J.D.; Duarte, J.L.; Wijnands, C.G.E.; Lomonova, E.A.

2014-01-01

An approach for three-phase AC to DC conversion is proposed, which consists of a single-stage while offering galvanic isolation, soft-switching, bi-directional power flow and a significant reduction of inductive and capacitive energy storage. Two elements enable this approach, namely a neutral

Simultaneous, single-pulse, synchrotron x-ray imaging and diffraction under gas gun loading

Energy Technology Data Exchange (ETDEWEB)

Fan, D.; Luo, S. N., E-mail: sluo@pims.ac.cn [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Huang, J. W.; Zeng, X. L.; Li, Y.; E, J. C.; Huang, J. Y. [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Sun, T.; Fezzaa, K. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Wang, Z. [Physics Division P-25, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-05-15

We develop a mini gas gun system for simultaneous, single-pulse, x-ray diffraction and imaging under high strain-rate loading at the beamline 32-ID of the Advanced Photon Source. In order to increase the reciprocal space covered by a small-area detector, a conventional target chamber is split into two chambers: a narrowed measurement chamber and a relief chamber. The gas gun impact is synchronized with synchrotron x-ray pulses and high-speed cameras. Depending on a camera’s capability, multiframe imaging and diffraction can be achieved. The proof-of-principle experiments are performed on single-crystal sapphire. The diffraction spots and images during impact are analyzed to quantify lattice deformation and fracture; fracture is dominated by splitting cracks followed by wing cracks, and diffraction peaks are broadened likely due to mosaic spread. Our results demonstrate the potential of such multiscale measurements for studying high strain-rate phenomena at dynamic extremes.

Hot fuel gas dedusting after sorbent-based gas cleaning

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-07-01

Advanced power generation technologies, such as Air Blown Gasification Cycle (ABGC), require gas cleaning at high temperatures in order to meet environmental standards and to achieve high thermal efficiencies. The primary hot gas filtration process, which removes particulates from the cooled raw fuel gas at up to 600{degree}C is the first stage of gas cleaning prior to desulphurization and ammonia removal processes. The dust concentration in the fuel gas downstream of the sorbent processes would be much lower than for the hot gas filtration stage and would have a lower sulphur content and possibly reduced chlorine concentration. The main aim of this project is to define the requirements for a hot gas filter for dedusting fuel gas under these conditions, and to identify a substantially simpler and more cost effective solution using ceramic or metal barrier filters.

Simulation model of a single-stage lithium bromide-water absorption cooling unit

Science.gov (United States)

Miao, D.

1978-01-01

A computer model of a LiBr-H2O single-stage absorption machine was developed. The model, utilizing a given set of design data such as water-flow rates and inlet or outlet temperatures of these flow rates but without knowing the interior characteristics of the machine (heat transfer rates and surface areas), can be used to predict or simulate off-design performance. Results from 130 off-design cases for a given commercial machine agree with the published data within 2 percent.

Maximizing the performance of a multiple-stage variable-throat venturi scrubber for particle collection

Science.gov (United States)

Muir, D. M.; Akeredolu, F.

The high collection efficiencies that are required nowadays to meet the stricter pollution control standards necessitate the use of high-energy scrubbers, such as the venturi scrubber, for the arrestment of fine particulate matter from exhaust gas streams. To achieve more energy-efficient particle collection, several venturi stages may be used in series. This paper is principally a theoretical investigation of the performance of a multiple-stage venturi scrubber, the main objective of the study being to establish the best venturi design configuration for any given set of operating conditions. A mathematical model is used to predict collection efficiency vs pressure drop relationships for particle sizes in the range 0.2-5.0 μm for one-, two-, three- and four-stage scrubbers. The theoretical predictions are borne out qualitatively by experimental work. The paper shows that the three-stage venturi produces the highest collection efficiencies over the normal operating range except for the collection of very fine particles at low pressure drops, when the single-stage venturi is best. The significant improvement in performance achieved by the three-stage venturi when compared with conventional single-stage operation increases as both the particle size and system pressure drop increase.

Single-stage MPPT control realization for Aalborg inverter in photovoltaic system

DEFF Research Database (Denmark)

Zhang, Shuai; Wu, Weimin; Wang, Houqing

2017-01-01

In this paper, the single-stage Maximum Power Point Tracking (MPPT) control strategy for the Aalborg photovoltaic inverter is presented. Aalborg inverter has many advantages, such as high efficiency, wide range of input voltage, minimum voltage drop of the filtering inductors, etc. Nevertheless......, it is essentially a “half-bridge” inverter with two input sources, where one source works in MPPT mode, the other is out of control. If without the reasonable parameter design and the proper control, the bus-voltage of this inverter may change greatly, resulting in the serious power oscillation around maximum power...

A multi-stage traveling-wave thermoacoustically-driven refrigeration system operating at liquefied natural gas temperature

Science.gov (United States)

Luo, K.; Sun, D. M.; Zhang, J.; Shen, Q.; Zhang, N.

2017-12-01

This study proposes a multi-stage travelling-wave thermoacoustically refrigeration system (TAD-RS) operating at liquefied natural gas temperature, which consists of two thermoacoustic engines (TAE) and one thermoacoustic refrigerator (TAR) in a closed-loop configuration. Three thermoacoustic units connect each other through a resonance tube of small cross-sectional area, achieving “self-matching” for efficient thermoacoustic conversion. Based on the linear thermoacoustic theory, a model of the proposed system has been built by using DeltaEC program to show the acoustic field characteristics and performance. It is shown that with pressurized 5 MPa helium as working gas, the TAEs are able to build a stable and strong acoustic field with a frequency of about 85 Hz. When hot end temperature reaches 923 K, this system can provide about 1410 W cooling power at 110 K with an overall exergy efficiency of 15.5%. This study indicates a great application prospect of TAD-RS in the field of natural gas liquefaction with a large cooling capacity and simple structure.

Radon depletion in xenon boil-off gas

Energy Technology Data Exchange (ETDEWEB)

Bruenner, S.; Cichon, D.; Lindemann, S.; Undagoitia, T.M.; Simgen, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

2017-03-15

An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of {sup 222}Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of >or similar 4 for the {sup 222}Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based α-detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10{sup -15} mol/mol level. (orig.)

Single-dose volume regulation algorithm for a gas-compensated intrathecal infusion pump.

Science.gov (United States)

Nam, Kyoung Won; Kim, Kwang Gi; Sung, Mun Hyun; Choi, Seong Wook; Kim, Dae Hyun; Jo, Yung Ho

2011-01-01

The internal pressures of medication reservoirs of gas-compensated intrathecal medication infusion pumps decrease when medication is discharged, and these discharge-induced pressure drops can decrease the volume of medication discharged. To prevent these reductions, the volumes discharged must be adjusted to maintain the required dosage levels. In this study, the authors developed an automatic control algorithm for an intrathecal infusion pump developed by the Korean National Cancer Center that regulates single-dose volumes. The proposed algorithm estimates the amount of medication remaining and adjusts control parameters automatically to maintain single-dose volumes at predetermined levels. Experimental results demonstrated that the proposed algorithm can regulate mean single-dose volumes with a variation of 98%. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Tranexamic acid for control of blood loss in bilateral total knee replacement in a single stage

Directory of Open Access Journals (Sweden)

Mandeep S Dhillon

2011-01-01

Full Text Available Background: Tranexamic acid (TEA reduces blood loss and red cell transfusions in patients undergoing unilateral total knee arthroplasty (TKA. However, there is not much literature regarding the use of TEA in patients undergoing bilateral TKA in a single stage and the protocols for administration of TEA in such patients are ill-defined. Materials and Methods: We carried out a case control study evaluating the effect of TEA on postoperative hemoglobin (Hb, total drain output, and number of blood units transfused in 52 patients undergoing bilateral TKA in a single stage, and compared it with 56 matched controls who did not receive TEA. Two doses of TEA were administered in doses of 10 mg / kg each (slow intravenous (IV infusion, with the first dose given just before tourniquet release of the first knee and the second dose three hours after the first one. Results: A statistically significant reduction in the total drain output and requirement of allogenic blood transfusion in cases who received TEA, as compared to the controls was observed. The postoperative Hb and Hb at the time of discharge were found to be lower in the control group, and this result was found to be statistically significant. Conclusion: TEA administered in patients undergoing single stage bilateral TKA helped reduce total blood loss and decreased allogenic blood transfusion requirements. This might be particularly relevant, where facilities such as autologous reinfusion might not be available.

Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

Energy Technology Data Exchange (ETDEWEB)

Romero-Hermida, M. I. [Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, Campus Río San Pedro s/n, 11510 Puerto Real (Spain); Departamento de Física Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Romero-Enrique, J. M. [Departamento de Física Atómica, Molecular y Nuclear, Área de Física Teórica, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Morales-Flórez, V.; Esquivias, L. [Departamento de Física Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Instituto de Ciencia de Materiales de Sevilla (CSIC/US), Av. Américo Vespucio 49, 41092 Sevilla (Spain)

2016-08-21

Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N{sub 2}, CO{sub 2}, and O{sub 2}, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO{sub 2} adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO{sub 2} adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO{sub 2} adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO{sub 2} adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO{sub 2} concentrations and low temperatures, the CO{sub 2} adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.

Predictive Modelling of Concentration of Dispersed Natural Gas in a Single Room

Directory of Open Access Journals (Sweden)

Abdulfatai JIMOH

2009-07-01

Full Text Available This paper aimed at developing a mathematical model equation to predict the concentration of natural gas in a single room. The model equation was developed by using theoretical method of predictive modelling. The model equation developed is as given in equation 28. The validity of the developed expression was tested through the simulation of experimental results using computer software called MathCAD Professional. Both experimental and simulated results were found to be in close agreement. The statistical analysis carried out through the correlation coefficients for the results of experiment 1, 2, 3 and 4 were found to be 0.9986, 1.0000, 0.9981 and 0.9999 respectively, which imply reasonable close fittings between the experimental and simulated concentrations of dispersed natural gas within the room. Thus, the model equation developed can be considered a good representation of the phenomena that occurred when there is a leakage or accidental release of such gas within the room.

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

Science.gov (United States)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-03-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

Single stage high pressure centrifugal slurry pump

Science.gov (United States)

Meyer, John W.; Bonin, John H.; Daniel, Arnold D.

1984-03-27

Apparatus is shown for feeding a slurry to a pressurized housing. An impeller that includes radial passages is mounted in the loose fitting housing. The impeller hub is connected to a drive means and a slurry supply means which extends through the housing. Pressured gas is fed into the housing for substantially enveloping the impeller in a bubble of gas.

Fuel staging tests at the Kymijaervi power plant

International Nuclear Information System (INIS)

Kivelae, M.; Rotter, H.; Virkki, J.

1990-01-01

The aim of this study was to measure nitrogen oxide (NO x ) emissions and find the methods to reduce them in plants using coal and natural gas as fuel. The tests involved were made at the Kymijaervi Power Plant, Lahti, Finland. Coal and natural gas was used alone or mixed. With natural gas when using flue gas recirculation, the NO x emission level dropped from 330 mg/m 3 down to 60 mg/m 3 . A negative side effect was that the flue gas temperature increased. At coal combustion and staged combustion, the flue gas recirculation had no significant effect on the NO x emission level. At coal combustion, the staging of combustion air halved the NO x emission but the combustibles increased strongly. With fuel staging, using coal as main fuel and gas as staging fuel, the NO x emission level was decreased from 340 mg/m 3 to 170 mg/m 3 . At the same time the combustibles increased 2 %- units. Also the flue gas temperature increased a little. At the tests, the proportion of natural gas was rather high, one third of the fuel energy input, but it could not be decreased, because the gas flow ratio was already too low to ensure good mixing

Feasibility study of generating ultra-high harmonic radiation with a single stage echo-enabled harmonic generation scheme

Energy Technology Data Exchange (ETDEWEB)

Zhou, Kaishang, E-mail: zhoukaishang@sinap.ac.cn; Feng, Chao, E-mail: fengchao@sinap.ac.cn; Wang, Dong, E-mail: wangdong@sinap.ac.cn

2016-10-21

The echo enabled harmonic generation (EEHG) scheme holds the ability for the generation of fully coherent soft x-ray free-electron laser (FEL) pulses directly from external UV seeding sources. In this paper, we study the feasibility of using a single stage EEHG to generate coherent radiation in the “water window” and beyond. Using the high-order operating modes of the EEHG scheme, intensive numerical simulations have been performed considering various three-dimensional effects. The simulation results demonstrated that coherent soft x-ray radiation at 150th harmonic (1.77 nm) of the seed can be produced by a single stage EEHG. The decreasing of the final bunching factor at the desired harmonic caused by intra beam scattering (IBS) effect has also been analyzed.

Leveling off the energy demand. Air conditioning by town gas NEXT STAGE. Energy juyo no heijunka wo motomete. Gas reibo NEXT STAGE

Energy Technology Data Exchange (ETDEWEB)

Watanabe, K. (Keio Univ., Tokyo (Japan). Faculty of Science and Technology)

1994-07-01

Utilizing various types of energy with combining them rationally is now drawing attention. One of these types of energy is the town gas. The air conditioning by town gas draws a special attention. The town gas is characterized by environmental conservation, energy saving, and comfortability. The town gas does not contain sulfur compounds which cause the acid rain. The town gas produces the least amount of carbon dioxide among all the fossil fuel. The air conditioning by the town gas is getting popular. Examples are Tokyo Dome in Tokyo, Pavilion Plaza, a new shopping spot in Fukuoka, Umeda Sky Building in Osaka, Dai-ich Apparel Center in Tokyo, Ohno Memorial Hospital in Osaka, Nagoya Municipal Integrated Stadium in Nagoya, Meguro-Gajoen in Tokyo, and New Yomiuri-Shimbun Building in Sapporo. 41 figs.

Studying the effect of over-modulation on the output voltage of three-phase single-stage grid-connected boost inverter

Directory of Open Access Journals (Sweden)

A. Abbas Elserougi

2013-09-01

Full Text Available Voltage boosting is very essential issue in renewable-energy fed applications. The classical two-stage power conversion process is typically used to interface the renewable energy sources to the grid. For better efficiency, single-stage inverters are recommended. In this paper, the performance of single-stage three-phase grid-connected boost inverter is investigated when its gain is extended by employing over-modulation technique. Using of over-modulation is compared with the employment of third order harmonic injection. The latter method can increase the inverter gain by 15% without distorting the inverter output voltage. The performance of extended gain grid-connected boost inverter is also tested during normal operation as well as in the presence of grid side disturbances. Simulation and experimental results are satisfactory.

Growth of Cd0.96Zn0.04Te single crystals by vapor phase gas transport method

Directory of Open Access Journals (Sweden)

S. H. Tabatabai Yazdi

2006-03-01

Full Text Available   Cd0.96Zn0.04Te crystals were grown using vapor phase gas transport method (VPGT. The results show that dendritic crystals with grain size up to 3.5 mm can be grown with this technique. X-ray diffraction and Laue back-reflection patterns show that dendritic crystals are single-phase, whose single crystal grains are randomly oriented with respect to the gas-transport axis. Electrical measurements, carried out using Van der Pauw method, show that the as-grown crystals have resistivity of about 104 Ω cm and n-type conductivity.

Analysis of U and Pu resin bead samples with a single stage mass spectrometer

International Nuclear Information System (INIS)

Smith, D.H.; Walker, R.L.; Bertram, L.K.; Carter, J.A.

1979-01-01

Resin bead sampling enables the shipment of nanogram U and Pu quantities for analysis. Application of this sampling technique to safeguards was investigated with a single-stage mass spectrometer. Standards gave results in good agreement with NBS certified values. External precisions of +-0.5% were obtained on isotopic ratios of approx. 0.01; precisions on quantitative measurements are +-1.0%

Single-stage revision for fungal peri-prosthetic joint infection: a single-centre experience.

Science.gov (United States)

Klatte, T O; Kendoff, D; Kamath, A F; Jonen, V; Rueger, J M; Frommelt, L; Gebauer, M; Gehrke, T

2014-04-01

Fungal peri-prosthetic infections of the knee and hip are rare but likely to result in devastating complications. In this study we evaluated the results of their management using a single-stage exchange technique. Between 2001 and 2011, 14 patients (ten hips, four knees) were treated for a peri-prosthetic fungal infection. One patient was excluded because revision surgery was not possible owing to a large acetabular defect. One patient developed a further infection two months post-operatively and was excluded from the analysis. Two patients died of unrelated causes. After a mean of seven years (3 to 11) a total of ten patients were available for follow-up. One patient, undergoing revision replacement of the hip, had a post-operative dislocation. Another patient, undergoing revision replacement of the knee, developed a wound infection and required revision 29 months post-operatively following a peri-prosthetic femoral fracture. The mean Harris hip score increased to 74 points (63 to 84; p prosthetic infection is feasible, with an acceptable rate of a satisfactory outcome.

Reliability Omnipotent Analysis For First Stage Separator On The Separation Process Of Gas, Oil And Water

International Nuclear Information System (INIS)

Sony Tjahyani, D. T.; Ismu W, Puradwi; Asmara Santa, Sigit

2001-01-01

Reliability of industry can be evaluated based on two aspects which are risk and economic aspects. From these points, optimation value can be determined optimation value. Risk of the oil refinery process are fire and explosion, so assessment of this system must be done. One system of the oil refinery process is first stage separator which is used to separate gas, oil and water. Evaluation of reliability for first stage separator system has been done with FAMECA and HAZap method. The analysis results, the probability of fire and explosion of 1.1x10 - 2 3 /hour and 1.2x10 - 1 1 /hour, respectively. The reliability value of the system is high because each undesired event is anticipated with safety system or safety component

A Single-Stage High-Power-Factor Light-Emitting Diode (LED Driver with Coupled Inductors for Streetlight Applications

Directory of Open Access Journals (Sweden)

Chun-An Cheng

2017-02-01

Full Text Available This paper presents and implements a single-stage high-power-factor light-emitting diode (LED driver with coupled inductors, suitable for streetlight applications. The presented LED driver integrates an interleaved buck-boost power factor correction (PFC converter with coupled inductors and a half-bridge-type series-resonant converter cascaded with a full-bridge rectifier into a single-stage power conversion circuit. Coupled inductors inside the interleaved buck-boost PFC converter sub-circuit are designed to operate in discontinuous conduction mode (DCM for achieving input-current shaping, and the half-bridge-type series resonant converter cascaded with a full-bridge rectifier is designed for obtaining zero-voltage switching (ZVS on two power switches to reduce their switching losses. Analysis of operational modes and design equations for the presented LED driver are described and included. In addition, the presented driver features a high power factor, low total harmonic distortion (THD of input current, and soft switching. Finally, a prototype driver is developed and implemented to supply a 165-W-rated LED streetlight module with utility-line input voltages ranging from 210 to 230 V. Experimental results demonstrate that high power factor (>0.99, low utility-line current THD (<7%, low-output voltage ripples (<1%, low-output current ripples (<10%, and high circuit efficiency (>90% are obtained in the presented single-stage driver for LED streetlight applications.

Fault Diagnosis for Engine Based on Single-Stage Extreme Learning Machine

Directory of Open Access Journals (Sweden)

Fei Gao

2016-01-01

Full Text Available Single-Stage Extreme Learning Machine (SS-ELM is presented to dispose of the mechanical fault diagnosis in this paper. Based on it, the traditional mapping type of extreme learning machine (ELM has been changed and the eigenvectors extracted from signal processing methods are directly regarded as outputs of the network’s hidden layer. Then the uncertainty that training data transformed from the input space to the ELM feature space with the ELM mapping and problem of the selection of the hidden nodes are avoided effectively. The experiment results of diesel engine fault diagnosis show good performance of the SS-ELM algorithm.

Economic dispatch of a single micro-gas turbine under CHP operation

International Nuclear Information System (INIS)

Rist, Johannes F.; Dias, Miguel F.; Palman, Michael; Zelazo, Daniel; Cukurel, Beni

2017-01-01

Highlights: •Economic dispatch of a micro gas turbine is considered for smart grid integration. •A detailed thermodynamic cycle analysis is conducted for variable load CHP operation. •Benefits are shown for case studies with real demand profiles and energy tariffs. •Optimal unit schedule can be electricity, heat, revenue or maintenance-cost driven. -- Abstract: This work considers the economic dispatch of a single micro-gas turbine under combined heat and power (CHP) operation. A detailed thermodynamic cycle analysis is conducted on a representative micro-gas turbine unit with non-constant component efficiencies and recuperator bypass. Based on partial and full load configurations, an accurate optimization model is developed for solving the economic dispatch problem of integrating the turbine into the grid. The financial benefit and viability of this approach is then examined on four detailed scenarios using real data on energy demand profiles and electricity tariffs. The analysis considers the optimal operation in a large hotel, a full-service restaurant, a small hotel, and a residential neighborhood during various seasons. The optimal schedule follows four fundamental economic drivers which are electricity, heat, revenue, and maintenance-cost driven.

Single-staged vs. two-staged implant placement using bone ring technique in vertically deficient alveolar ridges - Part 1: histomorphometric and micro-CT analysis.

Science.gov (United States)

Nakahara, Ken; Haga-Tsujimura, Maiko; Sawada, Kosaku; Kobayashi, Eizaburo; Mottini, Matthias; Schaller, Benoit; Saulacic, Nikola

2016-11-01

Simultaneous implant placement with bone grafting shortens the overall treatment period, but might lead to the peri-implant bone loss or even implant failure. The aim of this study was to compare the single-staged to two-staged implant placement using the bone ring technique. Four standardized alveolar bone defects were made in the mandibles of nine dogs. Dental implants (Straumann BL ® , Basel, Switzerland) were inserted simultaneously with bone ring technique in test group and after 6 months of healing period in control group. Animals of both groups were euthanized at 3 and 6 months of osseointegration period. The harvested samples were analyzed by means of histology and micro-CT. The amount of residual bone decreased while the amount of new bone increased up to 9 months of healing period. All morphometric parameters remained stable between 3 and 6 months of osseointegration period within groups. Per a given time point, median area of residual bone graft was higher in test group and area of new bone in control group. The volume of bone ring was greater in test than in control group, reaching the significance at 6 months of osseointegration period (P = 0.002). In the present type of bone defect, single-staged implant placement may be potentially useful to shorten an overall treatment period. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The production of hydrogen through the use of a 77 wt% Pd 23 wt% Ag membrane water gas shift reactor

CSIR Research Space (South Africa)

Baloyi, Liberty N

2016-12-01

Full Text Available stainless steel (PSS) is evaluated for the production of hydrogen and the potential replacement of the current two-stage Water-Gas Shift (WGS) reaction by a single stage reaction. The permeability of a 20 µm Pd–Ag membrane reactor was examined at 320 °C, 380...

Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

Science.gov (United States)

Jeon, Juncheol; Han, Chulhee; Chung, Jye Ung; Choi, Seung-Bok

2015-01-01

In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains.

Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

International Nuclear Information System (INIS)

Jeon, Juncheol; Han, Chulhee; Ung Chung, Jye; Choi, Seung-Bok

2015-01-01

In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains. (paper)

Experimental study of single-electron loss by Ar+ ions in rare-gas atoms

Science.gov (United States)

Reyes, P. G.; Castillo, F.; Martínez, H.

2001-04-01

Absolute differential and total cross sections for single-electron loss were measured for Ar+ ions on rare-gas atoms in the laboratory energy range of 1.5 to 5.0 keV. The electron loss cross sections for all the targets studied are found to be in the order of magnitude between 10-19 and 10-22 cm2, and show a monotonically increasing behaviour as a function of the incident energy. The behaviour of the total single-electron loss cross sections with the atomic target number, Zt, shows different dependences as the collision energy increases. In all cases the present results display experimental evidence of saturation in the single-electron loss cross section as the atomic number of the target increases.

Forecasting cracked collectors on anticlinal type structures at late stage of exploration in oil and gas area

Science.gov (United States)

Hasanov, M. A.; Aleksandrov, B. L.; Eljayev, A. S.; Ezirbaev, T. B.; Gatsaeva, S. S.

2017-10-01

The possibility of using complex information on morphological parameters of structures, block porosity and the reservoir pressure gradient over previously explored deposits for the development of a multidimensional equation for estimating secondary porosity is considered. This is examined by the example of reservoirs with secondary (fractured) porosity of the Upper Cretaceous carbonate deposits of the Tersko-Sunzhenskaya oil and gas bearing region of the Ciscaucasia. The use of this equation makes it possible to predict the magnitude of the secondary porosity on the anticlinal structures, which are newly discovered by seismic methods at a later stage of exploration in the relevant oil and gas region, as a quantitative criterion that predicts the presence of a trap.

Influence of heat exchange of reservoir with rocks on hot gas injection via a single well

Science.gov (United States)

Nikolaev, Vladimir E.; Ivanov, Gavril I.

2017-11-01

In the computational experiment the influence of heat exchange through top and bottom of the gas-bearing reservoir on the dynamics of temperature and pressure fields during hot gas injection via a single well is investigated. The experiment was carried out within the framework of modified mathematical model of non-isothermal real gas filtration, obtained from the energy and mass conservation laws and the Darcy law. The physical and caloric equations of state together with the Newton-Riemann law of heat exchange of gas reservoir with surrounding rocks, are used as closing relations. It is shown that the influence of the heat exchange with environment on temperature field of the gas-bearing reservoir is localized in a narrow zone near its top and bottom, though the size of this zone is increased with time.

Advanteges of using Two-Switch Forward in Single-Stage Power Factor Corrected Power Supplies

DEFF Research Database (Denmark)

Petersen, Lars

2000-01-01

A single-Stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (Discontinues Conduction Mode). This will insure the intermediate DC-bus to be controlled only by means of circuit parameters and therefore...... power supply has been implemented. The measured efficiency and power factor are about 87% and 0.96 respectively....

Single stage buck-boost DC-AC neutral point clamped inverter

DEFF Research Database (Denmark)

Mo, Wei; Loh, Poh Chiang; Andrew, A.

2012-01-01

This paper proposes a new single stage buck-boost DC-AC neutral point clamped inverter topology which integrates the cascaded configurations of recently introduced inductor-capacitor-capacitor-transformer impedance source network (by Adamowicz) and classic NPC configuration. As a consequence......, it has enhanced buck-boost functionality and low output voltage distortions compared to the traditional Z-source inverter; it has continuous input current which reduces the source stress and inverter noise; it also contains two built-in capacitors which can block the DC current in the transformer...... windings thus preventing the core from saturation; lowers the voltage stresses and power losses of inverter switches and reduces the sizes of filtering devices and as well as obtains better output performance compared to the original two-level Z-source inverters. A phase disposition pulse width modulation...

Multi-stage versus single-stage inflation and deflation cycle for alternating low pressure air mattresses to prevent pressure ulcers in hospitalised patients: a randomised-controlled clinical trial.

Science.gov (United States)

Demarré, L; Beeckman, D; Vanderwee, K; Defloor, T; Grypdonck, M; Verhaeghe, S

2012-04-01

The duration and the amount of pressure and shear must be reduced in order to minimize the risk of pressure ulcer development. Alternating low pressure air mattresses with multi-stage inflation and deflation cycle of the air cells have been developed to relieve pressure by sequentially inflating and deflating the air cells. Evidence about the effectiveness of this type of mattress in clinical practice is lacking. This study aimed to compare the effectiveness of an alternating low pressure air mattress that has a standard single-stage inflation and deflation cycle of the air cells with an alternating low pressure air mattress with multi-stage inflation and deflation cycle of the air cells. A randomised controlled trial was performed in a convenience sample of 25 wards in five hospitals in Belgium. In total, 610 patients were included and randomly assigned to the experimental group (n=298) or the control group (n=312). In the experimental group, patients were allocated to an alternating low pressure air mattress with multi-stage inflation and deflation cycle of the air cells. In the control group, patients were allocated to an alternating low pressure air mattress with a standard single-stage inflation and deflation cycle of the air cells. The outcome was defined as cumulative pressure ulcer incidence (Grade II-IV). An intention-to-treat analysis was performed. There was no significant difference in cumulative pressure ulcer incidence (Grade II-IV) between both groups (Exp.=5.7%, Contr.=5.8%, p=0.97). When patients developed a pressure ulcer, the median time was 5.0 days in the experimental group (IQR=3.0-8.5) and 8.0 days in the control group (IQR=3.0-8.5) (Mann-Whitney U-test=113, p=0.182). The probability to remain pressure ulcer free during the observation period in this trial did not differ significantly between the experimental group and the control group (log-rank χ(2)=0.013, df=1, p=0.911). An alternating low pressure air mattress with multi-stage inflation

Performance and genome-centric metagenomics of thermophilic single and two-stage anaerobic digesters treating cheese wastes

DEFF Research Database (Denmark)

Fontana, Alessandra; Campanaro, Stefano; Treu, Laura

2018-01-01

-depth characterization of the microbial community structure using genome-centric metagenomics. Both reactor configurations showed acidification problems under the tested organic loading rates (OLRs) of 3.6 and 2.4 g COD/L-reactor day and the hydraulic retention time (HRT) of 15 days. However, the two-stage design...... of the main population genomes highlighted specific metabolic pathways responsible for the AD process and the mechanisms of main intermediates production. Particularly, the acetate accumulation experienced by the single stage configuration was mainly correlated to the low abundant syntrophic acetate oxidizer...

A further step toward H2 in automobile : development of an efficient bi-functional catalyst for single stage water gas shift

NARCIS (Netherlands)

Azzam, K.G.H.

2008-01-01

The suitability of polymer electrolyte fuel (PEM) cells for stationary and vehicular applications initiated research in all areas of fuel processor (i.e. reformer, water-gas-shift, preferential oxidation of CO (PROX)) catalysts for hydrogen generation. Water gas shift (WGS) reaction is an essential

High Precision Motion Control System for the Two-Stage Light Gas Gun at the Dynamic Compression Sector

Science.gov (United States)

Zdanowicz, E.; Guarino, V.; Konrad, C.; Williams, B.; Capatina, D.; D'Amico, K.; Arganbright, N.; Zimmerman, K.; Turneaure, S.; Gupta, Y. M.

2017-06-01

The Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS), located at Argonne National Laboratory (ANL), has a diverse set of dynamic compression drivers to obtain time resolved x-ray data in single event, dynamic compression experiments. Because the APS x-ray beam direction is fixed, each driver at DCS must have the capability to move through a large range of linear and angular motions with high precision to accommodate a wide variety of scientific needs. Particularly challenging was the design and implementation of the motion control system for the two-stage light gas gun, which rests on a 26' long structure and weighs over 2 tons. The target must be precisely positioned in the x-ray beam while remaining perpendicular to the gun barrel axis to ensure one-dimensional loading of samples. To accommodate these requirements, the entire structure can pivot through 60° of angular motion and move 10's of inches along four independent linear directions with 0.01° and 10 μm resolution, respectively. This presentation will provide details of how this system was constructed, how it is controlled, and provide examples of the wide range of x-ray/sample geometries that can be accommodated. Work supported by DOE/NNSA.

Single-stage-to-orbit — Meeting the challenge

Science.gov (United States)

Freeman, Delma C.; Talay, Theodore A.; Austin, Robert Eugene

1996-02-01

There has been and continues to be significant discussion about the viability of fully reusable, single-stage-to-orbit (SSTO) concepts for delivery of payloads to orbit. Often, these discussions have focused in detail on performance and technology requirements relating to the technical feasibility of the concept, with only broad generalizations on how the SSTO will achieve its economic goals of greatly reduced vehicle ground and flight operations costs. With the current industry and NASA Reusable Launch Vehicle Technology Program efforts underway to mature and demonstrate technologies leading to a viable commercial launch system that also satisfies national needs, achieving acceptable recurring costs becomes a significant challenge. This paper reviews the current status of the Reusable Launch Vehicle Technology Program including the DC-XA, X-33, X-34 flight systems and associated technology programs. The paper also examines lessons learned from the recently completed DC-X reusable rocket demonstrator program. It examines how these technologies and flight systems address the technical and operability challenges of SSTO whose solutions are necessary to reduce costs. The paper also discusses the management and operational approaches that address the challenge of a new cost-effective, reusable launch vehicle system.

CMOS single-stage input-powered bridge rectifier with boost switch and duty cycle control

Science.gov (United States)

Radzuan, Roskhatijah; Mohd Salleh, Mohd Khairul; Hamzah, Mustafar Kamal; Ab Wahab, Norfishah

2017-06-01

This paper presents a single-stage input-powered bridge rectifier with boost switch for wireless-powered devices such as biomedical implants and wireless sensor nodes. Realised using CMOS process technology, it employs a duty cycle switch control to achieve high output voltage using boost technique, leading to a high output power conversion. It has only six external connections with the boost inductance. The input frequency of the bridge rectifier is set at 50 Hz, while the switching frequency is 100 kHz. The proposed circuit is fabricated on a single 0.18-micron CMOS die with a space area of 0.024 mm2. The simulated and measured results show good agreement.

Electrochemistry of single nanobubbles. Estimating the critical size of bubble-forming nuclei for gas-evolving electrode reactions.

Science.gov (United States)

German, Sean R; Edwards, Martin A; Chen, Qianjin; Liu, Yuwen; Luo, Long; White, Henry S

2016-12-12

In this article, we address the fundamental question: "What is the critical size of a single cluster of gas molecules that grows and becomes a stable (or continuously growing) gas bubble during gas evolving reactions?" Electrochemical reactions that produce dissolved gas molecules are ubiquitous in electrochemical technologies, e.g., water electrolysis, photoelectrochemistry, chlorine production, corrosion, and often lead to the formation of gaseous bubbles. Herein, we demonstrate that electrochemical measurements of the dissolved gas concentration, at the instant prior to nucleation of an individual nanobubble of H 2 , N 2 , or O 2 at a Pt nanodisk electrode, can be analyzed using classical thermodynamic relationships (Henry's law and the Young-Laplace equation - including non-ideal corrections) to provide an estimate of the size of the gas bubble nucleus that grows into a stable bubble. We further demonstrate that this critical nucleus size is independent of the radius of the Pt nanodisk employed (gas. For example, the measured critical surface concentration of H 2 of ∼0.23 M at the instant of bubble formation corresponds to a critical H 2 nucleus that has a radius of ∼3.6 nm, an internal pressure of ∼350 atm, and contains ∼1700 H 2 molecules. The data are consistent with stochastic fluctuations in the density of dissolved gas, at or near the Pt/solution interface, controlling the rate of bubble nucleation. We discuss the growth of the nucleus as a diffusion-limited process and how that process is affected by proximity to an electrode producing ∼10 11 gas molecules per second. Our study demonstrates the advantages of studying a single-entity, i.e., an individual nanobubble, in understanding and quantifying complex physicochemical phenomena.

Single-step generation of metal-plasma polymer multicore@shell nanoparticles from the gas phase.

Science.gov (United States)

Solař, Pavel; Polonskyi, Oleksandr; Olbricht, Ansgar; Hinz, Alexander; Shelemin, Artem; Kylián, Ondřej; Choukourov, Andrei; Faupel, Franz; Biederman, Hynek

2017-08-17

Nanoparticles composed of multiple silver cores and a plasma polymer shell (multicore@shell) were prepared in a single step with a gas aggregation cluster source operating with Ar/hexamethyldisiloxane mixtures and optionally oxygen. The size distribution of the metal inclusions as well as the chemical composition and the thickness of the shells were found to be controlled by the composition of the working gas mixture. Shell matrices ranging from organosilicon plasma polymer to nearly stoichiometric SiO 2 were obtained. The method allows facile fabrication of multicore@shell nanoparticles with tailored functional properties, as demonstrated here with the optical response.

Neurologic Injury and Cerebral Blood Flow In Single Ventricles Throughout Staged Surgical Reconstruction

Science.gov (United States)

Fogel, Mark A.; Li, Christine; Elci, Okan U.; Pawlowski, Tom; Schwab, Peter J.; Wilson, Felice; Nicolson, Susan C.; Montenegro, Lisa M.; Diaz, Laura; Spray, Thomas L.; Gaynor, J William; Fuller, Stephanie; Mascio, Christopher; Keller, Marc S.; Harris, Matthew A.; Whitehead, Kevin K.; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J.

2017-01-01

Background Single ventricle patients experience a high rate of brain injury and adverse neurodevelopmental outcome, however, the incidence of brain abnormalities throughout surgical reconstruction and its relationship with cerebral blood flow, oxygen delivery and carbon dioxide reactivity remains unknown. Methods Single ventricle patients were studied with MRI scans immediately prior to bidirectional Glenn (pre-BDG), prior to Fontan and then 3–9 months after Fontan reconstruction. Results One hundred and sixty eight consecutive subjects recruited into the project underwent 235 scans: 63 pre-BDG (mean age 4.8+1.7 months), 118 BDG (2.9+1.4 years) and 54 after Fontan (2.4+1.0 years). Non-acute ischemic white matter changes on T2 weighted imaging, focal tissue loss, and ventriculomegaly were all more commonly detected in BDG and Fontans compared to pre-BDG (P<0.05). BDG patients has significantly higher CBF than Fontan patients. The odds of discovering brain injury adjusting for surgical stage as well as 2 or more co-existing lesions within a patient all decreased (63–75% and 44% respectively) with increasing amount of cerebral blood flow (P<0.05). In general, there was no association of oxygen delivery (with the exception of ventriculomegaly in the BDG group) or carbon dioxide reactivity with neurological injury. Conclusion Significant brain abnormalities are commonly present in single ventricle patients and detection of these lesions increase as children progress through staged surgical reconstruction with multiple co-existing lesions more common earlier than later. In addition, this study demonstrated that BDG patients had greater CBF than Fontan patients and that there exists an inverse association of various indices of CBF with these brain lesions, however, CO2 reactivity, oxygen delivery (with one exception) were not associated with brain lesion development. PMID:28031423

Investigation of different ethylenediamine-N,N'-disuccinic acid-enhanced washing configurations for remediation of a Cu-contaminated soil: process kinetics and efficiency comparison between single-stage and multi-stage configurations.

Science.gov (United States)

Ferraro, Alberto; Fabbricino, Massimiliano; van Hullebusch, Eric D; Esposito, Giovanni

2017-09-01

A comparison of Cu extraction yields for three different ethylenediamine-N,N'-disuccinic acid (EDDS)-enhanced washing configurations was performed on a Cu-contaminated soil. Batch experiments were used to simulate a single-stage continuous stirred tank reactor (CSTR) and a multi-stage (side feeding and counter-current) reactor. Single-stage CSTR conditions were simulated for various EDDS:(Cu + Cd + Pb + Co + Ni + Zn) molar ratio (EDDS:M ratio) (from 1 to 30) and liquid to soil (L/S) ratio (from 15 to 45). The highest Cu extraction yield (≃56%) was achieved with EDDS:M = 30. In contrast, a Cu extraction yield decrease was observed with increasing L/S ratio with highest extracted Cu achievement (≃48%) for L/S = 15. Side feeding configuration was tested in four experimental conditions through different fractionation mode of EDDS dose and treatment time at each washing step. Results from the four tests showed all enhanced Cu extraction (maximum values from ≃43 to ≃51%) achieved at lower treatment time and lower EDDS:M molar ratio compared to CSTR configuration with L/S = 25 and EDDS:M = 10. The counter-current washing was carried out through two washing flows achieving a process performance enhancement with 27% increase of extracted Cu compared to single-stage CSTR configuration. Higher Cu extraction percentage (36.8%) was observed in the first washing phase than in the second one (24.7%).

Control of a Two-Stage Direct Power Converter with a Single Voltage Sensor Mounted in the Intermediary Circuit

DEFF Research Database (Denmark)

Klumpner, Christian; Wheeler, P.; Blaabjerg, Frede

2004-01-01

Controlling a converter requires not only a powerful processors but also accurate voltage and current sensors and fast and precise analogue-digital converters, which increase the cost per kW of the assembly, especially in the low power range. A matrix converter requires less transducers than a back...... converters but in two stages (AC/DC/AC) without using energy storage in the intermediary circuit. They also offer the possibility to reduce the number of switches compared to the standard single-stage matrix converter. This paper presents a new method to control a two-stage DPC providing sine-wave in sine...

Evaluation and compensation of steady gas flow force on the high-pressure electro-pneumatic servo valve direct-driven by voice coil motor

International Nuclear Information System (INIS)

Li, Baoren; Gao, Longlong; Yang, Gang

2013-01-01

Highlights: ► A novel energy saving high-pressure electro-pneumatic servo valve is presented. ► An evaluated method for steady gas flow forces on pneumatic valves is proposed. ► Gas jet angles at the orifices for the valve are larger than 69° commonly used. ► The steady gas flow force is strongly nonlinear with valve opening. ► The steady gas flow force is compensated and the aim at energy saving is realized. - Abstract: A novel voice coil motor (VCM) direct drive single stage high-pressure pneumatic servo valve is designed, and then the steady gas flow force acting on the spool of the servo valve is investigated by numerical simulation and experimental methods in this paper. At present, many studies about flow force are concentrated mainly on hydraulic valves, but rarely on pneumatic valves. However, the velocity of gas is up to sonic when high-pressure gas flows through the servo valve orifice. And therefore, the steady gas flow force, generated by high pressure and high speed gas flow, cannot be neglected and is an important disturbance for the VCM direct-drive single stage high-pressure pneumatic servo valve. Consequently, the numerical simulation with computational fluid dynamics (CFD) is adopted to analyze the flow filed, jet angles, and steady gas flow forces for the servo valve with different valve openings and inlet pressures. The experimental study is performed to evaluate and confirm the numerical analysis. Then the compensated approach is proposed to reduce the steady gas flow force for the servo valve, changing the angle of non-metering port designed in the valve sleeve to the spool axis. The results demonstrate that the presented numerical analysis method is validated, the gas jet angle for the servo valve orifice is more than 69° and varies with different spool openings, and the steady gas flow force is nonlinear with valve opening and linear with inlet pressure when the outlet boundary is atmospheric pressure. Moreover, the steady gas

Single-stage laparoscopic common bile duct exploration and cholecystectomy versus two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy for patients with concomitant gallbladder stones and common bile duct stones: a randomized controlled trial.

Science.gov (United States)

Bansal, Virinder Kumar; Misra, Mahesh C; Rajan, Karthik; Kilambi, Ragini; Kumar, Subodh; Krishna, Asuri; Kumar, Atin; Pandav, Chandrakant S; Subramaniam, Rajeshwari; Arora, M K; Garg, Pramod Kumar

2014-03-01

The ideal method for managing concomitant gallbladder stones and common bile duct (CBD) stones is debatable. The currently preferred method is two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy (LC). This prospective randomized trial compared the success and cost effectiveness of single- and two-stage management of patients with concomitant gallbladder and CBD stones. Consecutive patients with concomitant gallbladder and CBD stones were randomized to either single-stage laparoscopic CBD exploration and cholecystectomy (group 1) or endoscopic retrograde cholangiopancreatography (ERCP) for endoscopic extraction of CBD stones followed by LC (group 2). Success was defined as complete clearance of CBD and cholecystectomy by the intended method. Cost effectiveness was measured using the incremental cost-effectiveness ratio. Intention-to-treat analysis was performed to compare outcomes. From February 2009 to October 2012, 168 patients were randomized: 84 to the single-stage procedure (group 1) and 84 to the two-stage procedure (group 2). Both groups were matched with regard to demographic and clinical parameters. The success rates of laparoscopic CBD exploration and ERCP for clearance of CBD were similar (91.7 vs. 88.1 %). The overall success rate also was comparable: 88.1 % in group 1 and 79.8 % in group 2 (p = 0.20). Direct choledochotomy was performed in 83 of the 84 patients. The mean operative time was significantly longer in group 1 (135.7 ± 36.6 vs. 72.4 ± 27.6 min; p ≤ 0.001), but the overall hospital stay was significantly shorter (4.6 ± 2.4 vs. 5.3 ± 6.2 days; p = 0.03). Group 2 had a significantly greater number of procedures per patient (p gallbladder and CBD stones had similar success and complication rates, but the single-stage strategy was better in terms of shorter hospital stay, need for fewer procedures, and cost effectiveness.

Early stages in the history of gas chromatography.

Science.gov (United States)

Kolomnikov, Ivan G; Efremov, Alexander M; Tikhomirova, Tatyana I; Sorokina, Nadezhda M; Zolotov, Yury A

2018-02-16

The creation of gas chromatography is traditionally associated with the names of Nobel Prize winner Archer Martin and his colleagues Richard Synge and Anthony James. However, sometimes references to their predecessors can be found. An investigation conducted by the authors of this article not only confirmed the reliability of these references; but in fact led to the conclusion that by 1952, which is commonly believed to be the year when gas chromatography was born, many research papers had already been devoted to this method, mainly, in its gas-solid version. These papers are considered in this article. Copyright © 2018. Published by Elsevier B.V.

Lengthening Temporalis Myoplasty for Single-Stage Smile Reconstruction in Children with Facial Paralysis.

Science.gov (United States)

Panossian, Andre

2016-04-01

Free muscle transfer for dynamic smile reanimation in facial paralysis is not always predictable with regard to cosmesis. Hospital stays range from 5 to 7 days. Prolonged operative times, longer hospital stays, and excessive cheek bulk are associated with free flap options. Lengthening temporalis myoplasty offers single-stage smile reanimation with theoretical advantages over free tissue transfer. From 2012 to 2014, 18 lengthening temporalis myoplasties were performed in 14 children for smile reconstruction. A retrospective chart review was completed for demographics, operative times, length of hospital stay, and perioperative complications. Fourteen consecutive patients with complete facial paralysis were included. Four patients underwent single-stage bilateral reconstruction, and 10 underwent unilateral procedures. Diagnoses included Möbius syndrome (n = 5), posterior cranial fossa tumors (n = 4), posttraumatic (n = 2), hemifacial microsomia (n = 1), and idiopathic (n = 2). Average patient age was 10.1 years. Average operative time was 410 minutes (499 minutes for bilateral lengthening temporalis myoplasty and 373 for unilateral lengthening temporalis myoplasty). Average length of stay was 3.3 days (4.75 days for bilateral lengthening temporalis myoplasty and 2.8 for unilateral lengthening temporalis myoplasty). Nine patients required minor revisions. Lengthening temporalis myoplasty is a safe alternative to free tissue transfer for dynamic smile reconstruction in children with facial paralysis. Limited donor-site morbidity, shorter operative times, and shorter hospital stays are some benefits over free flap options. However, revisions are required frequently secondary to tendon avulsions and adhesions. Therapeutic, IV.

Hearing rehabilitation with single-stage bilateral vibroplasty in a child with Franceschetti syndrome.

Science.gov (United States)

Sargsyan, Sona; Rahne, Torsten; Kösling, Sabrina; Eichler, Gerburg; Plontke, Stefan K

2014-05-01

Hearing is of utmost importance for normal speech and social development. Even children who have mild or unilateral permanent hearing loss may experience difficulties with understanding speech, as well as problems with educational and psycho-social development. The increasing advantages of middle-ear implant technologies are opening new perspectives for restoring hearing. Active middle-ear implants can be used in children and adolescents with hearing loss. In addition to the well-documented results for improving speech intelligibility and quality of hearing in sensorineural hearing loss active middle-ear implants are now successfully used in patients with conductive and mixed hearing loss. In this article we present a case of successful, single-stage vibroplasty, on the right side with the fixation of the FMT on the stapes and PORP CLiP vibroplasty on the left side in a 6-year-old girl with bilateral mixed hearing loss and multiple dyslalia associated with Franceschetti syndrome (mandibulofacial dysostosis). CT revealed bilateral middle-ear malformations as well as an atretic right and stenotic left external auditory canal. Due to craniofacial dysmorphia airway and (post)operative, management is significantly more difficult in patients with a Franceschetti syndrome which in this case favoured a single-stage bilateral procedure. No intra- or postoperative surgical complications were reported. The middle-ear implants were activated 4 weeks after surgery. In the audiological examination 6 months after surgery, the child showed 100% speech intelligibility with activated implants on each side.

Area G perimeter surface-soil and single-stage water sampling. Environmental surveillance for fiscal year 95. Progress report

International Nuclear Information System (INIS)

Childs, M.; Conrad, R.

1997-09-01

ESH-19 personnel collected soil and single-stage water samples around the perimeter of Area G at Los Alamos National Laboratory (LANL) during FY 95 to characterize possible radionuclide movement out of Area G through surface water and entrained sediment runoff. Soil samples were analyzed for tritium, total uranium, isotopic plutonium, americium-241, and cesium-137. The single-stage water samples were analyzed for tritium and plutonium isotopes. All radiochemical data was compared with analogous samples collected during FY 93 and 94 and reported in LA-12986 and LA-13165-PR. Six surface soils were also submitted for metal analyses. These data were included with similar data generated for soil samples collected during FY 94 and compared with metals in background samples collected at the Area G expansion area

Single-stage-to-orbit performance enhancement from take-off thrust augmentation

Science.gov (United States)

Galati, Terence; Elkins, Travis

1997-01-01

Thrust augmentation offers the Single Stage to Orbit (SSTO) space launch vehicle improved payload capability while reducing vehicle weight and cost. Optimization of vehicle configuration and flight profile are studied. Using a 612,000 kg Gross Lift Off Weight (GLOW) SSTO with three Castor® strap-on motors, payloads in excess of 18,000 kg to Low Earth Orbit (LEO) are achievable. Emphasis is placed on finding vehicle optimums in the 9,000 kg payload range to capture over 80% of commercial payloads. Strap-on boosters allow a small SSTO vehicle to fly with a mass fraction of only 0.88 and LOX/H2 engines operating at 445 sec vacuum specific impulse. Payload sensitivity due to variations of mass fraction, Isp and pitch rate are quantified.

Gas-exchange patterns of Mediterranean fruit fly Pupae (Diptera: Tephritidae): A tool to forecast developmental stage

International Nuclear Information System (INIS)

Nestel, D.; Nemny-Lavy, E.; Alchanatis, V.

2007-01-01

The pattern of gas-exchange (CO 2 emission) was investigated for developing Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) pupae incubated at different temperatures. This study was undertaken to explore the usefulness of gas-exchange systems in the determination of physiological age in developing pupae that are mass produced for sterile insect technique projects. The rate of CO 2 emission was measured in a closed flow-through system connected to commercial infrared gas analysis equipment. Metabolic activity (rate of CO 2 emission) was related to pupal eye-color, which is the current technique used to determine physiological age. Eye-color was characterized digitally with 3 variables (Hue, Saturation and Intensity), and color separated by discriminant analysis. The rate of CO 2 emission throughout pupal development followed a U-shape, with high levels of emission during pupariation, pupal transformation and final pharate adult stages. Temperature affected the development time of pupae, but not the basic CO 2 emission patterns during development. In all temperatures, rates of CO 2 emission 1 and 2 d before adult emergence were very similar. After mid larval-adult transition (e.g., phanerocephalic pupa), digital eye-color was significantly correlated with CO 2 emission. Results support the suggestion that gas-exchange should be explored further as a system to determine pupal physiological age in mass production of fruit flies. (author) [es

Tissue Expansion Using Hyaluronic Acid Filler for Single-Stage Ear Reconstruction: A Novel Concept for Difficult Areas.

Science.gov (United States)

Inbal, Amir; Lemelman, Benjamin T; Millet, Eran; Greensmith, Andrew

2017-10-16

Auricular reconstruction is one of the most challenging procedures in plastic surgery. An adequate skin envelope is essential for cartilage framework coverage, yet few good options exist without additional surgery. We propose a novel method for minimally invasive tissue expansion, using hyaluronic acid (HA) filler to allow for single-stage ear reconstruction. To introduce the novel concept of HA filler for tissue expansion in ear reconstruction, and as an alternative to traditional expansion techniques. Macrolane is a large particle HA gel developed for large volume restoration. Expansion of the non-hair-bearing mastoid skin was performed in our clinic weekly or every other week. Final expansion was completed one week prior to reconstructive surgery. Tissue from one patient's expanded pocket was sent for histological analysis. Ten patients underwent single-stage auricular reconstruction with preoperative expansion. Injection sessions ranged from 7 to 13 (mean, 9.7). Mean injected volume per session was 2.03 mL per patient, for an average total of 19.8 mL (range, 14.5-30 mL). There were no major complications. One minor complication required removal of exposed wire from the antihelix in the office. Hematoxylin and eosin stain revealed similar histology to that seen with traditional expanders. This novel expansion technique using serial HA injections allowed for optimized skin coverage in single-stage ear reconstruction. The concept of tissue expansion using HA filler is a new frontier for research that may be applicable to other arenas of reconstruction. 4. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

Stability investigation of a high number density Pt1/Fe2O3 single-atom catalyst under different gas environments by HAADF-STEM

Science.gov (United States)

Duan, Sibin; Wang, Rongming; Liu, Jingyue

2018-05-01

Catalysis by supported single metal atoms has demonstrated tremendous potential for practical applications due to their unique catalytic properties. Unless they are strongly anchored to the support surfaces, supported single atoms, however, are thermodynamically unstable, which poses a major obstacle for broad applications of single-atom catalysts (SACs). In order to develop strategies to improve the stability of SACs, we need to understand the intrinsic nature of the sintering processes of supported single metal atoms, especially under various gas environments that are relevant to important catalytic reactions. We report on the synthesis of high number density Pt1/Fe2O3 SACs using a facial strong adsorption method and the study of the mobility of these supported Pt single atoms at 250 °C under various gas environments that are relevant to CO oxidation, water–gas shift, and hydrogenation reactions. Under the oxidative gas environment, Fe2O3 supported Pt single atoms are stable even at high temperatures. The presence of either CO or H2 molecules in the gas environment, however, facilitates the movement of the Pt atoms. The strong interaction between CO and Pt weakens the binding between the Pt atoms and the support, facilitating the movement of the Pt single atoms. The dissociation of H2 molecules on the Pt atoms and their subsequent interaction with the oxygen species of the support surfaces dislodge the surface oxygen anchored Pt atoms, resulting in the formation of Pt clusters. The addition of H2O molecules to the CO or H2 significantly accelerates the sintering of the Fe2O3 supported Pt single atoms. An anchoring-site determined sintering mechanism is further proposed, which is related to the metal–support interaction.

Performance analysis of single stage libr-water absorption machine operated by waste thermal energy of internal combustion engine: Case study

Science.gov (United States)

Sharif, Hafiz Zafar; Leman, A. M.; Muthuraman, S.; Salleh, Mohd Najib Mohd; Zakaria, Supaat

2017-09-01

Combined heating, cooling, and power is also known as Tri-generation. Tri-generation system can provide power, hot water, space heating and air -conditioning from single source of energy. The objective of this study is to propose a method to evaluate the characteristic and performance of a single stage lithium bromide-water (LiBr-H2O) absorption machine operated with waste thermal energy of internal combustion engine which is integral part of trigeneration system. Correlations for computer sensitivity analysis are developed in data fit software for (P-T-X), (H-T-X), saturated liquid (water), saturated vapor, saturation pressure and crystallization temperature curve of LiBr-H2O Solution. Number of equations were developed with data fit software and exported into excel work sheet for the evaluation of number of parameter concerned with the performance of vapor absorption machine such as co-efficient of performance, concentration of solution, mass flow rate, size of heat exchangers of the unit in relation to the generator, condenser, absorber and evaporator temperatures. Size of vapor absorption machine within its crystallization limits for cooling and heating by waste energy recovered from exhaust gas, and jacket water of internal combustion engine also presented in this study to save the time and cost for the facilities managers who are interested to utilize the waste thermal energy of their buildings or premises for heating and air conditioning applications.

A comparison of single knock-on and complete bubble destruction models of the fission induced re-solution of gas atoms from bubbles

International Nuclear Information System (INIS)

Wood, M.H.

1978-03-01

In previous theoretical studies of the behaviour of the fission gases in nuclear fuel, the Nelson single knock-on model of the fission induced re-solution of gas atoms from fission gas bubbles has been employed. In the present investigation, predictions from this model are compared with those from a complete bubble destruction model of the re-solution process. The main conclusions of the study are that the complete bubble destruction model predicts more gas release after a particular irradiation time than the single knock-on model, for the same choice of the model parameters, and that parameter sets chosen to give the same gas release predict significantly different bubble size distribution functions. (author)

Policy subjects of the LP gas industry; LP gas sangyo no seisaku kadai

Energy Technology Data Exchange (ETDEWEB)

Murata, K. [Agency of Natural Resources and Energy, Tokyo (Japan)

1996-09-01

The paper commented on current environmental changes in the LP gas industry and the measures for reinforcement of the physical constitution. When correction of the high cost structure in Japan is now the problem, waves of deregulation and rationalization reach to not only to LP gas but energy competitive with LP gas such as petroleum, electric power and town gas. With this, it is expected that LP gas will be faced with severe competition with other energy media. In the LP gas industry, business becomes more and more in number and smaller and smaller in scale as it extends downstream. Therefore, the resulting complicatedness in the distribution sector is the problem. It is necessary to realize scale profit in each distribution stage and to heighten productivity by expanding the scale in the retailing stage, especially. It is also important to tackle scale merit, improvement of productivity, and cost reduction by concentrating functions on either of wholesalers or retailers in every function of delivery, safety, free from each distribution stage.

New methodology for aquifer influx status classification for single wells in a gas reservoir with aquifer support

Directory of Open Access Journals (Sweden)

Yong Li

2016-10-01

Full Text Available For gas reservoirs with strong bottom or edge aquifer support, the most important thing is avoiding aquifer breakthrough in a gas well. Water production in gas wells does not only result in processing problems in surface facilities, but it also explicitly reduces well productivity and reservoir recovery. There are a lot of studies on the prediction of water breakthrough time, but they are not completely practicable due to reservoir heterogeneity. This paper provides a new method together with three diagnostic curves to identify aquifer influx status for single gas wells; the aforementioned curves are based on well production and pressure data. The whole production period of a gas well can be classified into three periods based on the diagnostic curves: no aquifer influx period, early aquifer influx period, and middle-late aquifer influx period. This new method has been used for actual gas well analysis to accurately identify gas well aquifer influx status and the water breakthrough sequence of all wells in the same gas field. Additionally, the evaluation results are significantly beneficial for well production rate optimization and development of an effective gas field.

A 5.4mW GPS CMOS quadrature front-end based on a single-stage LNA-mixer-VCO

DEFF Research Database (Denmark)

Liscidini, Amtonio; Mazzanti, Andrea; Tonietto, Riccardo

2006-01-01

A GPS RF front-end combines the LNA, mixer, and VCO in a single stage and can operate from a 1.2V supply. The chip is implemented in a 0.13um CMOS process and occupies 1.5mm2 active area. It consumes 5.4mW with a 4.8dB NF, 36dB gain, and a P1dB of -31dBm.......A GPS RF front-end combines the LNA, mixer, and VCO in a single stage and can operate from a 1.2V supply. The chip is implemented in a 0.13um CMOS process and occupies 1.5mm2 active area. It consumes 5.4mW with a 4.8dB NF, 36dB gain, and a P1dB of -31dBm....

A One ppm NDIR Methane Gas Sensor with Single Frequency Filter Denoising Algorithm

Directory of Open Access Journals (Sweden)

Binqing Jiang

2012-09-01

Full Text Available A non-dispersive infrared (NDIR methane gas sensor prototype has achieved a minimum detection limit of 1 parts per million by volume (ppm. The central idea of the design of the sensor is to decrease the detection limit by increasing the signal to noise ratio (SNR of the system. In order to decrease the noise level, a single frequency filter algorithm based on fast Fourier transform (FFT is adopted for signal processing. Through simulation and experiment, it is found that the full width at half maximum (FWHM of the filter narrows with the extension of sampling period and the increase of lamp modulation frequency, and at some optimum sampling period and modulation frequency, the filtered signal maintains a noise to signal ratio of below 1/10,000. The sensor prototype provides the key techniques for a hand-held methane detector that has a low cost and a high resolution. Such a detector may facilitate the detection of leakage of city natural gas pipelines buried underground, the monitoring of landfill gas, the monitoring of air quality and so on.

A clinical case of single-stage correction of penetration combined orofacial defect with two microsurgical autografts

Directory of Open Access Journals (Sweden)

A. D. Kaprin

2015-01-01

Full Text Available After surgical treatment for locally advanced oral tumors with resection of soft tissues, mucosal membrane, and facial skeletal structures, there are penetration combined defects, removal of which is a challenge for reconstructive surgeons. Mandibular repair is one of the problems in the correction of combined oral defects. Surgeons use different grafts to remove mandibular defects. One-flap transplantation does not always solve all reconstruction problems and ensure the repair of the mucosal membrane, a soft-tissue component, skin integuments, and facial skeleton.The authors describe a clinical case of successful single-stage correction of penetration combined orofacial defect after resection of the tongue, mouth floor, en bloc resection of the lower jaw and mental soft tissues, bilateral cervical supramyochoroidal lymphadenectomy, stage LCL CM mandibular defect formation after J. Boyd, by using two microsurgical autografts (a peroneal skin-muscle-skin autograft and a radial skin-fascia one in a 39-year-old female patient clinically diagnosed with carcinoma of the left mandibular alveolar ridge mucosa, Stage IVA (T4аN0M0.The Department of Microsurgery, P.A. Herzen Moscow Oncology Research Institute, Ministry of Health of Russia, has gained experience in comprehensively correcting extensive combined maxillofacial defects with two or more grafts in 27 patients who underwent autografting with a total of 73 flaps. The most functionally incapacitating and life-incompatible defect was removed at Stage 1 of reconstructive treatment. Delayed reconstruction was made after a complex of specialized antitumor therapy and assessment of treatment results in the absence of progressive growth. A great problem during multi-stage defect correction is presented by the lack of recipient vessels after cervical lymphadenectomy, the presence of soft tissue scar changes, trismus, temporomandibular joint ankylosis, contractures and displacement of the edges of the

The first preliminary experiments on an 84 GHz gyrotron with a single-stage depressed collector

International Nuclear Information System (INIS)

Shimozuma, T.; Sato, M.; Takita, Y.

1997-10-01

We fabricated and tested an 84GHz gyrotron with a single-stage depressed collector. The gyrotron has a high-voltage insulating section made of a low loss silicon nitride composite. In this preliminary experiment in the depressed collector configuration, we obtained 591kW, 41% operation with a depression voltage of 22.5kV. Access to the higher efficiency region was inhibited by an increase in anode current. (author)

Gas gun dynamics

International Nuclear Information System (INIS)

Denny, Mark

2013-01-01

The mechanics and thermodynamics of one- and two-stage gas guns are developed. Very high projectile muzzle speed can be obtained by the two-stage version. The physics of simple gas guns, such as air rifles, is accessible to undergraduates and the same level of presentation is used here to understand more complex designs. Numerical solutions to the equations of motion are shown, along with insightful analytic approximations. (paper)

Stages of Gas-Hydrate Evolution on the Northern Cascadia Margin

Directory of Open Access Journals (Sweden)

the IODP Expedition 311 Scientists

2006-09-01

Full Text Available Natural gas hydrate occurs beneath many continental slopes and in arctic permafrost areas. Recent studies have indicated that the largest deposits of gas hydrate might lie in nearly horizontal layers several hundred meters beneath the seafloor of continental slopes, especially in the large, accretionary sedimentary prisms of subduction zones. Expedition 311 of the Integrated Ocean Drilling Program (IODP investigated the formation of gas hydrate in the accretionary prism of the Cascadia subduction zone (Fig. 1. The primary objectives of Expedition 311 were to test and constraingeological models of gas hydrate formation by upward fluidand methane transport in accretionary prisms. We specifi -cally sought to (a determine the mechanisms that controlthe nature, magnitude, and distribution of the gas hydrate,(b find the pathways of the fluid migration required to formlarge concentrations of gas hydrate, (c examine the effectsof gas hydrate on the physical properties of the host sediment,and (d investigate the microbiology and geochemistryassociated with the occurrence of gas hydrate. Furthermore,we concentrated on the contrast between methane transportby focused fl ow in fault zones and by dispersed pervasiveupward flow at various scales of permeability.

Experimental study of single-electron loss by Ar{sup +} ions in rare-gas atoms

Energy Technology Data Exchange (ETDEWEB)

Reyes, P.G. [Facultad de Ciencias, UNAM, Coyoacan (Mexico); Castillo, F. [Instituto de Ciencias Nucleares, UNAM, Coyoacan (Mexico); Martinez, H. [Centro de Ciencias Fisicas, UNAM, Cuernavaca, Morelos (Mexico)]. E-mail: hm@fis.unam.mx

2001-04-28

Absolute differential and total cross sections for single-electron loss were measured for Ar{sup +} ions on rare-gas atoms in the laboratory energy range of 1.5 to 5.0 keV. The electron loss cross sections for all the targets studied are found to be in the order of magnitude between 10{sup -19} and 10{sup -22} cm{sup 2}, and show a monotonically increasing behaviour as a function of the incident energy. The behaviour of the total single-electron loss cross sections with the atomic target number, Z{sub t}, shows different dependences as the collision energy increases. In all cases the present results display experimental evidence of saturation in the single-electron loss cross section as the atomic number of the target increases. (author)

Two-stage coal liquefaction without gas-phase hydrogen

Science.gov (United States)

Stephens, H.P.

1986-06-05

A process is provided for the production of a hydrogen-donor solvent useful in the liquefaction of coal, wherein the water-gas shift reaction is used to produce hydrogen while simultaneously hydrogenating a donor solvent. A process for the liquefaction of coal using said solvent is also provided. The process enables avoiding the use of a separate water-gas shift reactor as well as high pressure equipment for liquefaction. 3 tabs.

Single-stage intraoperative transhepatic biliary stenting in patients with unresectable hepatobiliary pancreatic tumors.

Science.gov (United States)

Iwasaki, Yoshimi; Kubota, Keiichi; Kita, Junji; Katoh, Masato; Shimoda, Mitsugi; Sawada, Tokihiko; Iso, Yukihiro

2013-02-01

The current study was conducted to evaluate the safety and utility of intraoperative transhepatic biliary stenting (ITBS) in patients with unresectable malignant biliary obstruction (UMBO) diagnosed intraoperatively. In this study, 50 patients who underwent ITBS for UMBO between April 2001 and May 2009 were retrospectively reviewed. For 26 patients who underwent preoperative percutaneous transhepatic biliary drainage (PTBD), the expandable metallic stent (EMS) was inserted intraoperatively by the PTBD route in a single stage. For 24 patients, the intrahepatic bile ducts were intentionally dilated by injection of saline via the endoscopic nasobiliary drainage or the percutaneous transhepatic gallbladder drainage route, and the puncture was performed under intraoperative ultrasound guidance followed by guidewire and catheter insertion. Thereafter, the EMS was placed in the same manner. The initial postoperative complications and long-term results of ITBS were evaluated. In all cases, ITBS was technically successful. Stenting alone was performed in 22 patients and stenting combined with other procedures in 28 patients. Hospital mortality occurred for three patients (6 %), and complication-related mortality occurred in two cases (4 %). There were nine cases (18 %) of postoperative complications. The median survival time was 179 days, and the EMS patency time was 137 days. During the follow-up period, EMS occlusion occurred in 23 cases (46 %). Best supportive care was a significant independent risk factor for early mortality within 100 days after ITBS (p = 0.020, odds ratio, 9.398). Single-stage ITBS is feasible for palliation of UMBO and seems to have a low complication rate.

Comparison between gas puffing and supersonic molecular beam injection in plasma density feedback experiments in EAST

International Nuclear Information System (INIS)

Zheng, Xingwei; Li, Jiangang; Hu, Jiansheng; Li, Jiahong; Ding, Rui; Cao, Bin; Wu, Jinhua

2013-01-01

To achieve desirable plasma density control, a supersonic molecular beam injection (SMBI) feedback control system has been developed recently for the EAST tokamak. The performance of the SMBI and gas puffing (GP) feedback systems were used and compared. The performance of pulse width mode is better than that of pulse amplitude mode when GP was used for density feedback control. During one-day experiments, the variation of gas input and wall retention can be clarified into two stages. In the first stage the retention ratio is as high as 80–90%, and the gas input is about an order of 10 22 D 2 . However, in the second stage, the retention ratio is at a range of 50–70%. The gas input of a single discharge is small and the net wall retention grows slowly. The results of the SMBI feedback control experiment was analyzed. The shorter delay time of SMBI makes it faster at feeding back control the plasma density. The result showed that, compared with GP, the gas input of SMBI was decreased ∼30% and the wall retention was reduced ∼40%. This shows SMBI's advantage for the long pulse high density discharges in EAST. (paper)

Neurological Injury and Cerebral Blood Flow in Single Ventricles Throughout Staged Surgical Reconstruction.

Science.gov (United States)

Fogel, Mark A; Li, Christine; Elci, Okan U; Pawlowski, Tom; Schwab, Peter J; Wilson, Felice; Nicolson, Susan C; Montenegro, Lisa M; Diaz, Laura; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Mascio, Christopher; Keller, Marc S; Harris, Matthew A; Whitehead, Kevin K; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J

2017-02-14

Patients with a single ventricle experience a high rate of brain injury and adverse neurodevelopmental outcome; however, the incidence of brain abnormalities throughout surgical reconstruction and their relationship with cerebral blood flow, oxygen delivery, and carbon dioxide reactivity remain unknown. Patients with a single ventricle were studied with magnetic resonance imaging scans immediately prior to bidirectional Glenn (pre-BDG), before Fontan (BDG), and then 3 to 9 months after Fontan reconstruction. One hundred sixty-eight consecutive subjects recruited into the project underwent 235 scans: 63 pre-BDG (mean age, 4.8±1.7 months), 118 BDG (2.9±1.4 years), and 54 after Fontan (2.4±1.0 years). Nonacute ischemic white matter changes on T2-weighted imaging, focal tissue loss, and ventriculomegaly were all more commonly detected in BDG and Fontan compared with pre-BDG patients ( P <0.05). BDG patients had significantly higher cerebral blood flow than did Fontan patients. The odds of discovering brain injury with adjustment for surgical stage as well as ≥2 coexisting lesions within a patient decreased (63%-75% and 44%, respectively) with increasing amount of cerebral blood flow ( P <0.05). In general, there was no association of oxygen delivery (except for ventriculomegaly in the BDG group) or carbon dioxide reactivity with neurological injury. Significant brain abnormalities are commonly present in patients with a single ventricle, and detection of these lesions increases as children progress through staged surgical reconstruction, with multiple coexisting lesions more common earlier than later. In addition, this study demonstrated that BDG patients had greater cerebral blood flow than did Fontan patients and that an inverse association exists of various indexes of cerebral blood flow with these brain lesions. However, CO 2 reactivity and oxygen delivery (with 1 exception) were not associated with brain lesion development. URL: http

Self-Excited Single-Stage Power Factor Correction Driving Circuit for LED Lighting

Directory of Open Access Journals (Sweden)

Yong-Nong Chang

2014-01-01

Full Text Available This pa\tper proposes a self-excited single-stage high power factor LED lighting driving circuit. Being featured with power factor correction capability without needing any control devices, the proposed circuit structure is with low cost and suitable for commercial production. The power factor correction function is accomplished by using inductor in combination with a half-bridge quasi resonant converter to achieve active switching and yield out voltage regulation according to load requirement. Furthermore, the zero-voltage switching in the half-bridge converter can be attained to promote the overall performance efficiency of the proposed circuit. Finally, the validity and production availability of the proposed circuit will be verified as well.

Multi-disciplinary design optimization and performance evaluation of a single stage transonic axial compressor

International Nuclear Information System (INIS)

Lee, Sae Il; Lee, Dong Ho; Kim, Kyu Hong; Park, Tae Choon; Lim, Byeung Jun; Kang, Young Seok

2013-01-01

The multidisciplinary design optimization method, which integrates aerodynamic performance and structural stability, was utilized in the development of a single-stage transonic axial compressor. An approximation model was created using artificial neural network for global optimization within given ranges of variables and several design constraints. The genetic algorithm was used for the exploration of the Pareto front to find the maximum objective function value. The final design was chosen after a second stage gradient-based optimization process to improve the accuracy of the optimization. To validate the design procedure, numerical simulations and compressor tests were carried out to evaluate the aerodynamic performance and safety factor of the optimized compressor. Comparison between numerical optimal results and experimental data are well matched. The optimum shape of the compressor blade is obtained and compared to the baseline design. The proposed optimization framework improves the aerodynamic efficiency and the safety factor.

The Lifetime Estimate for ACSR Single-Stage Splice Connector Operating at Higher Temperatures

International Nuclear Information System (INIS)

Wang, Jy-An John; Graziano, Joe; Chan, John

2011-01-01

This paper is the continuation of Part I effort to develop a protocol of integrating analytical and experimental approaches to evaluate the integrity of a full tension single-stage splice connector (SSC) assembly during service at high operating temperature.1The Part II efforts are mainly focused on the thermal mechanical testing, thermal-cycling simulation and its impact on the effective lifetime of the SSC system. The investigation indicates that thermal cycling temperature and frequency, conductor cable tension loading, and the compressive residual stress field within a SSC system have significant impact on the SSC integrity and the associated effective lifetime.

Shape Optimization of the Assisted Bi-directional Glenn surgery for stage-1 single ventricle palliation

Science.gov (United States)

Verma, Aekaansh; Shang, Jessica; Esmaily-Moghadam, Mahdi; Wong, Kwai; Marsden, Alison

2016-11-01

Babies born with a single functional ventricle typically undergo three open-heart surgeries starting as neonates. The first of these stages (BT shunt or Norwood) has the highest mortality rates of the three, approaching 30%. Proceeding directly to a stage-2 Glenn surgery has historically demonstrated inadequate pulmonary flow (PF) & high mortality. Recently, the Assisted Bi-directional Glenn (ABG) was proposed as a promising means to achieve a stable physiology by assisting the PF via an 'ejector pump' from the systemic circulation. We present preliminary parametrization and optimization results for the ABG geometry, with the goal of increasing PF. To limit excessive pressure increases in the Superior Vena Cava (SVC), the SVC pressure is included as a constraint. We use 3-D finite element flow simulations coupled with a single ventricle lumped parameter network to evaluate PF & the pressure constraint. We employ a derivative free optimization method- the Surrogate Management Framework, in conjunction with the OpenDIEL framework to simulate multiple simultaneous evaluations. Results show that nozzle diameter is the most important design parameter affecting ABG performance. The application of these results to patient specific situations will be discussed. This work was supported by an NSF CAREER award (OCI1150184) and by the XSEDE National Computing Resource.

The effects of staged gas combustion on NO{sub x} formation; L'effet de la combustion etagee sur la formation de NO{sub x}

Energy Technology Data Exchange (ETDEWEB)

Wopera, A. [University of Miskolc (Hungary); Sandor, P.; Sevcsik, M. [Dunaferr Co. (Hungary)

2000-07-01

The use of energy involves air pollution unavoidably. As a result of the ongoing change of the structure of the fuels used in Hungary, the decisive majority of the heat treatment and annealing furnaces in our industrial companies operate with natural gas. With natural gas heating if the firing control is proper, only one important air pollutant, the nitrogen monoxide comes into being. NO{sub x} emission of firing processes may be reduced by staged fuel combustion. One of the traditional activities in the field of energetics is the utilization of the energy content of waste fuels. The recovery of the energy content of waste gases, which can be used as fuels, should be examined from both a heat technology and an environment protection point of view. There is the possibility of technological heat utilization when it is mixed with gases of high thermal value. Its utilization as combination gas also makes it necessary to examine how the waste gases change the polluting effects of natural gas. Our research work studied the NO{sub x} formation at different rate of mixing of natural gas and waste gases and the effect of secondary combustion chamber at a two-stage burner. (authors)

An operational protocol for facilitating start-up of single-stage autotrophic nitrogen-removing reactors based on process stoichiometry

DEFF Research Database (Denmark)

Mutlu, Ayten Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan

2013-01-01

Start-up and operation of single-stage nitritation–anammox sequencing batch reactors (SBRs) for completely autotrophic nitrogen removal can be challenging and far from trivial. In this study, a step-wise procedure is developed based on stoichiometric analysis of the process performance from...

A Gas Target Internal to the LHC for the Study of pp Single-Spin Asymmetries and Heavy Ion Collisions

Directory of Open Access Journals (Sweden)

Colin Barschel

2015-01-01

Full Text Available We discuss the application of an open storage cell as gas target for a proposed LHC fixed-target experiment AFTER@LHC. The target provides a high areal density at minimum gas input, which may be polarized 1H, 2H, or 3He gas or heavy inert gases in a wide mass range. For the study of single-spin asymmetries in pp interaction, luminosities of nearly 1033/cm2 s can be produced with existing techniques.

A Room-temperature Hydrogen Gas Sensor Using Palladium-decorated Single-Walled Carbon Nanotube/Si Heterojunction

Directory of Open Access Journals (Sweden)

Yong Gang DU

2016-05-01

Full Text Available We report a room-temperature (RT hydrogen gas (H2 sensor based on palladium-decorated single-walled carbon nanotube/Si (Pd-SWNTs/Si heterojunction. The current-voltage (I-V curves of the Pd-SWNTs/Si heterojunction in different concentrations of H2 were measured. The experimental results reveal that the Pd-SWNTs/Si heterojunction exhibits high H2 response. After exposure to 0.02 %, 0.05 %, and 0.1 % H2 for 10 min, the resistance of the heterojunction increases dramatically. The response is 122 %, 269 % and 457 %, respectively. A simple interfacial theory is used to understand the gas sensitivity results. This approach is a step toward future CNTs-based gas sensors for practical application.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12925

Anti-site defected MoS2 sheet-based single electron transistor as a gas sensor

Science.gov (United States)

Sharma, Archana; Husain, Mushahid; Srivastava, Anurag; Khan, Mohd. Shahid

2018-05-01

To prevent harmful and poisonous CO gas molecules, catalysts are needed for converting them into benign substances. Density functional theory (DFT) calculations have been used to study the adsorption of CO and CO2 gas molecules on the surface of MoS2 monolayer with Mo atom embedded at S-vacancy site (MoS). The strong interaction between Mo metal with pristine MoS2 sheet suggests its strong binding nature. Doping Mo into MoS2 sheet enhances CO and CO2 adsorption strength. The sensing response of MoS-doped MoS2 system to CO and CO2 gas molecules is obtained in the single electron transistor (SET) environment by varying bias voltage. Doping reduces charging energy of the device which results in fast switching of the device from OFF to ON state.

Achievement report for fiscal 1998. Research and development of ceramic gas turbine (Regenerative single-shaft ceramic gas turbine for cogeneration); 1998 nendo ceramic gas turbine no kenkyu kaihatsu seika hokokusho. Cogeneration yo saiseishiki ichijiku ceramic gas turbine

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-05-01

Efforts are exerted to develop a 300kW-class ceramic gas turbine with a turbine inlet temperature of 1350 degrees C and thermal efficiency of 42% or higher. The soundness in strength of the ceramic rotor blades and their fastening structure is confirmed. Rotor blade cushion thickness is found to decrease in start-and-stop repetitions in the initial period, but not thereafter. The exhaust diffuser and exhaust path shape are studied and improved for an increase in output, which improves turbine efficiency by 1.7%. Under the operating conditions of 1350 degrees C and full load, NOx emissions and combustion efficiency prove to be 5.6ppm and 99.9%. Even in the case using a large-diameter liner with its combustion efficiency under light load improved, the ultimate target value is achieved. Studies are further conducted on centrifugal stage loss reduction towards the ultimate goal set for the compressor. The diffuser shape is improved and the shroud clearance is reduced, and insulation efficiency of 81.1% is attained at the designing stage. In a test run of a pilot ceramic gas turbine in which temperature finally arrives at 1350 degrees C, engine thermal efficiency of 35% and shaft output of 282kW are achieved. (NEDO)

Xenon gas field ion source from a single-atom tip

Science.gov (United States)

Lai, Wei-Chiao; Lin, Chun-Yueh; Chang, Wei-Tse; Li, Po-Chang; Fu, Tsu-Yi; Chang, Chia-Seng; Tsong, T. T.; Hwang, Ing-Shouh

2017-06-01

Focused ion beam (FIB) systems have become powerful diagnostic and modification tools for nanoscience and nanotechnology. Gas field ion sources (GFISs) built from atomic-size emitters offer the highest brightness among all ion sources and thus can improve the spatial resolution of FIB systems. Here we show that the Ir/W(111) single-atom tip (SAT) can emit high-brightness Xe+ ion beams with a high current stability. The ion emission current versus extraction voltage was analyzed from 150 K up to 309 K. The optimal emitter temperature for maximum Xe+ ion emission was ˜150 K and the reduced brightness at the Xe gas pressure of 1 × 10-4 torr is two to three orders of magnitude higher than that of a Ga liquid metal ion source, and four to five orders of magnitude higher than that of a Xe inductively coupled plasma ion source. Most surprisingly, the SAT emitter remained stable even when operated at 309 K. Even though the ion current decreased with increasing temperature, the current at room temperature (RT) could still reach over 1 pA when the gas pressure was higher than 1 × 10-3 torr, indicating the feasibility of RT-Xe-GFIS for application to FIB systems. The operation temperature of Xe-SAT-GFIS is considerably higher than the cryogenic temperature required for the helium ion microscope (HIM), which offers great technical advantages because only simple or no cooling schemes can be adopted. Thus, Xe-GFIS-FIB would be easy to implement and may become a powerful tool for nanoscale milling and secondary ion mass spectroscopy.

Single fireball and fireball ideal gas

International Nuclear Information System (INIS)

Fiore, R.; Page, R.; Sertorio, L.

1977-01-01

In the paper the partition function of a macroscopic hadron system with two models is studied. In one model the mathematical fireball appears as a fundamental particle in a Boltzmann ideal gas occupying a volume V. In a second model the macroscopic volume V is divided in noninteracting boxes of volume Vsub(0), each one containing and interacting-pion gas. Both cases show the same limiting temperature Tsup(*) produced by the bootstrap equation, although far from Tsup(*) they represent different thermodynamic systems

An operation protocol for facilitating start-up of single-stage autotrophic nitrogen removing reactors based on process stoichiometry

DEFF Research Database (Denmark)

Mutlu, A. Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan

2012-01-01

Start-up and operation of single-stage nitritation/anammox reactor employing complete autotrophic nitrogen can be difficult. Keeping the performance criteria and monitoring the microbial community composition may not be easy or fast enough to take action on time. In this study, a control strategy...

The effectiveness of a single-stage versus traditional three-staged protocol of hospital disinfection at eradicating vancomycin-resistant Enterococci from frequently touched surfaces.

Science.gov (United States)

Friedman, N Deborah; Walton, Aaron L; Boyd, Sarah; Tremonti, Christopher; Low, Jillian; Styles, Kaylene; Harris, Owen; Alfredson, David; Athan, Eugene

2013-03-01

Environmental contamination is a reservoir for vancomycin-resistant enterococcus (VRE) in hospitals. Environmental sampling of surfaces was undertaken anytime before disinfection and 1 hour after disinfection utilizing a sodium dichloroisocyanurate-based, 3-staged protocol (phase 1) or benzalkonium chloride-based, single-stage clean (phase 2). VRE colonization and infection rates are presented from 2010 to 2011, and audits of cleaning completeness were also analyzed. Environmental samples collected before disinfection were significantly more likely to be contaminated with VRE during phase 1 than phase 2: 25.2% versus 4.6%, respectively; odds ratio (OR), 7.01 (P benzalkonium chloride-based product for disinfection. This reduction in VRE may be due to a new disinfection product, more attention to the thoroughness of cleaning, or other supplementary efforts in our institution. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Experimental Results of the First Two Stages of an Advanced Transonic Core Compressor Under Isolated and Multi-Stage Conditions

Science.gov (United States)

Prahst, Patricia S.; Kulkarni, Sameer; Sohn, Ki H.

2015-01-01

NASA's Environmentally Responsible Aviation (ERA) Program calls for investigation of the technology barriers associated with improved fuel efficiency of large gas turbine engines. Under ERA the task for a High Pressure Ratio Core Technology program calls for a higher overall pressure ratio of 60 to 70. This mean that the HPC would have to almost double in pressure ratio and keep its high level of efficiency. The challenge is how to match the corrected mass flow rate of the front two supersonic high reaction and high corrected tip speed stages with a total pressure ratio of 3.5. NASA and GE teamed to address this challenge by using the initial geometry of an advanced GE compressor design to meet the requirements of the first 2 stages of the very high pressure ratio core compressor. The rig was configured to run as a 2 stage machine, with Strut and IGV, Rotor 1 and Stator 1 run as independent tests which were then followed by adding the second stage. The goal is to fully understand the stage performances under isolated and multi-stage conditions and fully understand any differences and provide a detailed aerodynamic data set for CFD validation. Full use was made of steady and unsteady measurement methods to isolate fluid dynamics loss source mechanisms due to interaction and endwalls. The paper will present the description of the compressor test article, its predicted performance and operability, and the experimental results for both the single stage and two stage configurations. We focus the detailed measurements on 97 and 100 of design speed at 3 vane setting angles.

Vaginal Radical Trachelectomy for early stage cervical cancer. Results of the Danish National Single Center Strategy

DEFF Research Database (Denmark)

Hauerberg, L; Høgdall, C; Loft, A

2015-01-01

OBJECTIVE: To present and evaluate an unselected national single center strategy with fertility preserving trachelectomy in cervical cancer. In 2003 nationwide single-center referral of women for trachelectomies was agreed upon between all Danish departments performing cervical cancer surgery...... a total of 77 pregnancies. Of the 72 women 40 were referred to fertility treatment. First and second trimester miscarriage rates were 21.6% and 2.7%, respectively. A total of 53 children were born of which 41 were delivered after gestational week 34. CONCLUSION: This unselected national single center...... of 120 unselected consecutive VRTs were assessed. To obtain complete follow-up about fertility treatment, pregnancy and obstetric outcome the women filled out an electronic questionnaire. Median follow-up: 55.7 months. RESULTS: 85.8% of the patients had stage IB1 disease, 68.3% squamous cell carcinomas...

Design and analysis of a single stage to orbit nuclear thermal rocket reactor engine

Energy Technology Data Exchange (ETDEWEB)

Labib, Satira, E-mail: Satira.Labib@duke-energy.com; King, Jeffrey, E-mail: kingjc@mines.edu

2015-06-15

Graphical abstract: - Highlights: • Three NTR reactors are optimized for the single stage launch of 1–15 MT payloads. • The proposed rocket engines have specific impulses in excess of 700 s. • Reactivity and submersion criticality requirements are satisfied for each reactor. - Abstract: Recent advances in the development of high power density fuel materials have renewed interest in nuclear thermal rockets (NTRs) as a viable propulsion technology for future space exploration. This paper describes the design of three NTR reactor engines designed for the single stage to orbit launch of payloads from 1 to 15 metric tons. Thermal hydraulic and rocket engine analyses indicate that the proposed rocket engines are able to reach specific impulses in excess of 800 s. Neutronics analyses performed using MCNP5 demonstrate that the hot excess reactivity, shutdown margin, and submersion criticality requirements are satisfied for each NTR reactor. The reactors each consist of a 40 cm diameter core packed with hexagonal tungsten cermet fuel elements. The core is surrounded by radial and axial beryllium reflectors and eight boron carbide control drums. The 40 cm long reactor meets the submersion criticality requirements (a shutdown margin of at least $1 subcritical in all submersion scenarios) with no further modifications. The 80 and 120 cm long reactors include small amounts of gadolinium nitride as a spectral shift absorber to keep them subcritical upon submersion in seawater or wet sand following a launch abort.

Design and analysis of a single stage to orbit nuclear thermal rocket reactor engine

International Nuclear Information System (INIS)

Labib, Satira; King, Jeffrey

2015-01-01

Graphical abstract: - Highlights: • Three NTR reactors are optimized for the single stage launch of 1–15 MT payloads. • The proposed rocket engines have specific impulses in excess of 700 s. • Reactivity and submersion criticality requirements are satisfied for each reactor. - Abstract: Recent advances in the development of high power density fuel materials have renewed interest in nuclear thermal rockets (NTRs) as a viable propulsion technology for future space exploration. This paper describes the design of three NTR reactor engines designed for the single stage to orbit launch of payloads from 1 to 15 metric tons. Thermal hydraulic and rocket engine analyses indicate that the proposed rocket engines are able to reach specific impulses in excess of 800 s. Neutronics analyses performed using MCNP5 demonstrate that the hot excess reactivity, shutdown margin, and submersion criticality requirements are satisfied for each NTR reactor. The reactors each consist of a 40 cm diameter core packed with hexagonal tungsten cermet fuel elements. The core is surrounded by radial and axial beryllium reflectors and eight boron carbide control drums. The 40 cm long reactor meets the submersion criticality requirements (a shutdown margin of at least $1 subcritical in all submersion scenarios) with no further modifications. The 80 and 120 cm long reactors include small amounts of gadolinium nitride as a spectral shift absorber to keep them subcritical upon submersion in seawater or wet sand following a launch abort

Design and cold-air test of single-stage uncooled turbine with high work output

Science.gov (United States)

Moffitt, T. P.; Szanca, E. M.; Whitney, W. J.; Behning, F. P.

1980-01-01

A solid version of a 50.8 cm single stage core turbine designed for high temperature was tested in cold air over a range of speed and pressure ratio. Design equivalent specific work was 76.84 J/g at an engine turbine tip speed of 579.1 m/sec. At design speed and pressure ratio, the total efficiency of the turbine was 88.6 percent, which is 0.6 point lower than the design value of 89.2 percent. The corresponding mass flow was 4.0 percent greater than design.

A photovoltaic self-powered gas sensor based on a single-walled carbon nanotube/Si heterojunction.

Science.gov (United States)

Liu, L; Li, G H; Wang, Y; Wang, Y Y; Li, T; Zhang, T; Qin, S J

2017-12-07

We present a novel photovoltaic self-powered gas sensor based on a p-type single-walled carbon nanotube (SWNT) and n-type silicon (n-Si) heterojunction. The energy from visible light suffices to drive the device owing to a built-in electric field (BEF) induced by the differences between the Fermi levels of SWNTs and n-Si.

Modified classification and single-stage microsurgical repair of posttraumatic infected massive bone defects in lower extremities.

Science.gov (United States)

Yang, Yun-fa; Xu, Zhong-he; Zhang, Guang-ming; Wang, Jian-wei; Hu, Si-wang; Hou, Zhi-qi; Xu, Da-chuan

2013-11-01

Posttraumatic infected massive bone defects in lower extremities are difficult to repair because they frequently exhibit massive bone and/or soft tissue defects, serious bone infection, and excessive scar proliferation. This study aimed to determine whether these defects could be classified and repaired at a single stage. A total of 51 cases of posttraumatic infected massive bone defect in lower extremity were included in this study. They were classified into four types on the basis of the conditions of the bone defects, soft tissue defects, and injured limb length, including Type A (without soft tissue defects), Type B (with soft tissue defects of 10 × 20 cm or less), Type C (with soft tissue defects of 10 × 20 cm or more), and Type D (with the limb shortening of 3 cm or more). Four types of single-stage microsurgical repair protocols were planned accordingly and implemented respectively. These protocols included the following: Protocol A, where vascularized fibular graft was implemented for Type A; Protocol B, where vascularized fibular osteoseptocutaneous graft was implemented for Type B; Protocol C, where vascularized fibular graft and anterior lateral thigh flap were used for Type C; and Protocol D, where limb lengthening and Protocols A, B, or C were used for Type D. There were 12, 33, 4, and 2 cases of Types A, B, C, and D, respectively, according to this classification. During the surgery, three cases of planned Protocol B had to be shifted into Protocol C; however, all microsurgical repairs were completed. With reference to Johner-Wruhs evaluation method, the total percentage of excellent and good results was 82.35% after 6 to 41 months of follow-up. It was concluded that posttraumatic massive bone defects could be accurately classified into four types on the basis of the conditions of bone defects, soft tissue coverage, and injured limb length, and successfully repaired with the single-stage repair protocols after thorough debridement. Thieme Medical

An efficient and accurate two-stage fourth-order gas-kinetic scheme for the Euler and Navier-Stokes equations

Science.gov (United States)

Pan, Liang; Xu, Kun; Li, Qibing; Li, Jiequan

2016-12-01

For computational fluid dynamics (CFD), the generalized Riemann problem (GRP) solver and the second-order gas-kinetic scheme (GKS) provide a time-accurate flux function starting from a discontinuous piecewise linear flow distributions around a cell interface. With the adoption of time derivative of the flux function, a two-stage Lax-Wendroff-type (L-W for short) time stepping method has been recently proposed in the design of a fourth-order time accurate method for inviscid flow [21]. In this paper, based on the same time-stepping method and the second-order GKS flux function [42], a fourth-order gas-kinetic scheme is constructed for the Euler and Navier-Stokes (NS) equations. In comparison with the formal one-stage time-stepping third-order gas-kinetic solver [24], the current fourth-order method not only reduces the complexity of the flux function, but also improves the accuracy of the scheme. In terms of the computational cost, a two-dimensional third-order GKS flux function takes about six times of the computational time of a second-order GKS flux function. However, a fifth-order WENO reconstruction may take more than ten times of the computational cost of a second-order GKS flux function. Therefore, it is fully legitimate to develop a two-stage fourth order time accurate method (two reconstruction) instead of standard four stage fourth-order Runge-Kutta method (four reconstruction). Most importantly, the robustness of the fourth-order GKS is as good as the second-order one. In the current computational fluid dynamics (CFD) research, it is still a difficult problem to extend the higher-order Euler solver to the NS one due to the change of governing equations from hyperbolic to parabolic type and the initial interface discontinuity. This problem remains distinctively for the hypersonic viscous and heat conducting flow. The GKS is based on the kinetic equation with the hyperbolic transport and the relaxation source term. The time-dependent GKS flux function

Application of two-stage biofilter system for the removal of odorous compounds.

Science.gov (United States)

Jeong, Gwi-Taek; Park, Don-Hee; Lee, Gwang-Yeon; Cha, Jin-Myeong

2006-01-01

Biofiltration is a biological process which is considered to be one of the more successful examples of biotechnological applications to environmental engineering, and is most commonly used in the removal of odoriferous compounds. In this study, we have attempted to assess the efficiency with which both single and complex odoriferous compounds could be removed, using one- or two-stage biofiltration systems. The tested single odor gases, limonene, alpha-pinene, and iso-butyl alcohol, were separately evaluated in the biofilters. Both limonene and alpha-pinene were removed by 90% or more EC (elimination capacity), 364 g/m3/h and 321 g/m3/h, respectively, at an input concentration of 50 ppm and a retention time of 30 s. The iso-butyl alcohol was maintained with an effective removal yield of more than 90% (EC 375 g/m3/h) at an input concentration of 100 ppm. The complex gas removal scheme was applied with a 200 ppm inlet concentration of ethanol, 70 ppm of acetaldehyde, and 70 ppm of toluene with residence time of 45 s in a one- or two-stage biofiltration system. The removal yield of toluene was determined to be lower than that of the other gases in the one-stage biofilter. Otherwise, the complex gases were sufficiently eliminated by the two-stage biofiltration system.

Experimental study of a staged combustion system for stationary gas turbine applications

Science.gov (United States)

Lamont, Warren G.

Two optically accessible experimental test rigs were designed and constructed to investigate a staged or distributed combustion system for stationary gas turbine applications. The test rigs were fuelled with natural gas and featured two combustion zones: the main combustion zone (MCZ) and the secondary combustion zone (SCZ). The MCZ is a swirl stabilized dump combustor and the SCZ, which is axially downstream from the MCZ, is formed by a transverse jet injecting a premixed fuel/air mixture into the vitiated stream. After installing and commissioning the test rig, an emission survey was conducted to investigate the SCZ conditions, equivalence ratio and momentum ratio, that produce low NOx emissions and give a higher temperature rise before a simulated high pressure turbine than firing only the MCZ. The emission survey found several operating conditions that show the benefit of combustion staging. These beneficial conditions had an SCZ equivalence ratio between 0.41 and 1.12. The data from the emission survey was then used to create an artificial neural network (ANN). The ANN used a multi-layer feed-forward network architecture and was trained with experimental data using the backpropagation training algorithm. The ANN was then used to create performance maps and optimum operational regions were sought. Lastly, optical diagnostics were used to obtain information on the nature of the SCZ reactive jet. The diagnostics included high speed CH* chemiluminescence, OH planar laser induced fluorescence (PLIF) and dual-pump coherent anti-Stokes Raman scattering (CARS). The chemiluminescence and PLIF were used to qualitatively determine the size and shape of the transverse jet reaction zone. Dual-pump CARS was used to quantitatively determine the temperature and H2/N2 concentration ratio profile at the mid-plane of the transverse jet. Dual-pump CARS data was collected for four operating conditions but only one is presented in this dissertation. For the condition presented, the

A single blood test adjusted for different liver fibrosis targets improves fibrosis staging and especially cirrhosis diagnosis.

Science.gov (United States)

Calès, Paul; Boursier, Jérôme; Oberti, Frédéric; Moal, Valérie; Fouchard Hubert, Isabelle; Bertrais, Sandrine; Hunault, Gilles; Rousselet, Marie Christine

2018-04-01

Fibrosis blood tests are usually developed using significant fibrosis, which is a unique diagnostic target; however, these tests are employed for other diagnostic targets, such as cirrhosis. We aimed to improve fibrosis staging accuracy by simultaneously targeting biomarkers for several diagnostic targets. A total of 3,809 patients were included, comprising 1,012 individuals with chronic hepatitis C (CHC) into a derivation population and 2,797 individuals into validation populations of different etiologies (CHC, chronic hepatitis B, human immunodeficiency virus/CHC, nonalcoholic fatty liver disease, alcohol) using Metavir fibrosis stages as reference. FibroMeter biomarkers were targeted for different fibrosis-stage combinations into classical scores by logistic regression. Independent scores were combined into a single score reflecting Metavir stages by linear regression and called Multi-FibroMeter Version Second Generation (V2G). The primary objective was to combine the advantages of a test targeted for significant fibrosis (FibroMeter V2G ) with those of a test targeted for cirrhosis (CirrhoMeter V2G ). In the derivation CHC population, we first compared Multi-FibroMeter V2G to FibroMeter V2G and observed significant increases in the cirrhosis area under the receiver operating characteristic curve (AUROC), Obuchowski index (reflecting all fibrosis-stage AUROCs), and classification metric (six classes expressed as a correctly classified percentage) and a nonsignificant increase in significant fibrosis AUROC. Thereafter, we compared it to CirroMeter V2G and observed a nonsignificant increase in the cirrhosis AUROC. In all 3,809 patients, respective accuracies for Multi-FibroMeter V2G and FibroMeter V2G were the following: cirrhosis AUROC, 0.906 versus 0.878 ( P fibrosis AUROC, 0.833 versus 0.832 ( P = 0.366). Multi-FibroMeter V2G had the highest correlation with the area of portoseptal fibrosis and the highest reproducibility over time. Correct classification rates

Electron attachment to DNA single strands: gas phase and aqueous solution.

Science.gov (United States)

Gu, Jiande; Xie, Yaoming; Schaefer, Henry F

2007-01-01

The 2'-deoxyguanosine-3',5'-diphosphate, 2'-deoxyadenosine-3',5'-diphosphate, 2'-deoxycytidine-3',5'-diphosphate and 2'-deoxythymidine-3',5'-diphosphate systems are the smallest units of a DNA single strand. Exploring these comprehensive subunits with reliable density functional methods enables one to approach reasonable predictions of the properties of DNA single strands. With these models, DNA single strands are found to have a strong tendency to capture low-energy electrons. The vertical attachment energies (VEAs) predicted for 3',5'-dTDP (0.17 eV) and 3',5'-dGDP (0.14 eV) indicate that both the thymine-rich and the guanine-rich DNA single strands have the ability to capture electrons. The adiabatic electron affinities (AEAs) of the nucleotides considered here range from 0.22 to 0.52 eV and follow the order 3',5'-dTDP > 3',5'-dCDP > 3',5'-dGDP > 3',5'-dADP. A substantial increase in the AEA is observed compared to that of the corresponding nucleic acid bases and the corresponding nucleosides. Furthermore, aqueous solution simulations dramatically increase the electron attracting properties of the DNA single strands. The present investigation illustrates that in the gas phase, the excess electron is situated both on the nucleobase and on the phosphate moiety for DNA single strands. However, the distribution of the extra negative charge is uneven. The attached electron favors the base moiety for the pyrimidine, while it prefers the 3'-phosphate subunit for the purine DNA single strands. In contrast, the attached electron is tightly bound to the base fragment for the cytidine, thymidine and adenosine nucleotides, while it almost exclusively resides in the vicinity of the 3'-phosphate group for the guanosine nucleotides due to the solvent effects. The comparatively low vertical detachment energies (VDEs) predicted for 3',5'-dADP(-) (0.26 eV) and 3',5'-dGDP(-) (0.32 eV) indicate that electron detachment might compete with reactions having high activation barriers

Two-stage dental implants inserted in a one-stage procedure : a prospective comparative clinical study

NARCIS (Netherlands)

Heijdenrijk, Kees

2002-01-01

The results of this study indicate that dental implants designed for a submerged implantation procedure can be used in a single-stage procedure and may be as predictable as one-stage implants. Although one-stage implant systems and two-stage.

Pilot scale testing of biomass feedstocks for use in gasification/gas turbine based power generation systems

Energy Technology Data Exchange (ETDEWEB)

Najewicz, D.J.; Furman, A.H. [General Electric Corporate Research and Development Center, Schenectady, NY (United States)

1993-12-31

A biomass gasification pilot program was performed at the GE Corporate Research and Development Center using two types of biomass feedstock. The object of the testing was to determine the properties of biomass product gas and its` suitability as a fuel for gas turbine based power generation cycles. The test program was sponsored by the State of Vermont, the US Environmental Protection Agency, the US Department of Energy and Winrock International/US Agency for International Development. Gasification of bagasse and wood chip feedstock was performed at a feed rate of approximately one ton per hour, using the Ge pressurized fixed bed gasifier and a single stage of cyclone particulate removal, operating at a temperature of 1,000 F. Both biomass feedstocks were found to gasify easily, and gasification capacity was limited by volumetric capacity of the fuel feed equipment. The biomass product gas was analyzed for chemical composition, particulate loading, fuel bound nitrogen levels, sulfur and alkali metal content. The results of the testing indicated the combustion characteristics of the biomass product gas are compatible with gas turbine combustor requirements. However, the particulate removal performance of the pilot facility single stage cyclone was found to be inadequate to meet turbine particulate contamination specifications. In addition, alkali metals found in biomass based fuels, which are known to cause corrosion of high temperature gas turbine components, were found to exceed allowable levels in the fuel gas. These alkali metal compounds are found in the particulate matter (at 1000 F) carried over from the gasifier, thus improved particulate removal technology, designed specifically for biomass particulate characteristics could meet the turbine requirements for both particulate and alkali loading. The paper will present the results of the biomass gasification testing and discuss the development needs in the area of gas clean-up and turbine combustion.

Mathematical modeling of a single stage ultrasonically assisted distillation process.

Science.gov (United States)

Mahdi, Taha; Ahmad, Arshad; Ripin, Adnan; Abdullah, Tuan Amran Tuan; Nasef, Mohamed M; Ali, Mohamad W

2015-05-01

The ability of sonication phenomena in facilitating separation of azeotropic mixtures presents a promising approach for the development of more intensified and efficient distillation systems than conventional ones. To expedite the much-needed development, a mathematical model of the system based on conservation principles, vapor-liquid equilibrium and sonochemistry was developed in this study. The model that was founded on a single stage vapor-liquid equilibrium system and enhanced with ultrasonic waves was coded using MATLAB simulator and validated with experimental data for ethanol-ethyl acetate mixture. The effects of both ultrasonic frequency and intensity on the relative volatility and azeotropic point were examined, and the optimal conditions were obtained using genetic algorithm. The experimental data validated the model with a reasonable accuracy. The results of this study revealed that the azeotropic point of the mixture can be totally eliminated with the right combination of sonication parameters and this can be utilized in facilitating design efforts towards establishing a workable ultrasonically intensified distillation system. Copyright © 2014 Elsevier B.V. All rights reserved.

Study on performance and emission characteristics of a single cylinder diesel engine using exhaust gas recirculation

Directory of Open Access Journals (Sweden)

Anantha Raman Lakshmipathi

2017-01-01

Full Text Available Exhaust gas re-circulation is a method used in compression ignition engines to control and reduce NOx emission. These emissions are controlled by reducing the oxygen concentration inside the cylinder and thereby reducing the flame temperature of the charge mixture inside the combustion chamber. In the present investigation, experiments were performed to study the effect of exhaust gas re-circulation on performance and emission characteristics in a four stroke single cylinder, water cooled and constant speed diesel engine. The experiments were performed to study the performance and emissions for different exhaust gas re-circulation ratios of the engine. Performance parameters such as brake thermal efficiency, indicated thermal efficiency, specific fuel consumption, total fuel consumption and emission parameters such as oxides of nitrogen, unburned hydrocarbons, carbon monoxide, carbon dioxide and smoke opacity were measured. Reductions in NOx and CO2 were observed but other emissions like HC, CO, and smoke opacity were found to have increased with the usage of exhaust gas re-circulation. The 15% exhaust gas re-circulation was found optimum for the engine in the aspects of performance and emission.

3 kW single stage all-fiber Yb-doped single-mode fiber laser for highly reflective and highly thermal conductive materials processing

Science.gov (United States)

Ikoma, S.; Nguyen, H. K.; Kashiwagi, M.; Uchiyama, K.; Shima, K.; Tanaka, D.

2017-02-01

A 3 kW single stage all-fiber Yb-doped single-mode fiber laser with bi-directional pumping configuration has been demonstrated. Our newly developed high-power LD modules are employed for a high available pump power of 4.9 kW. The length of the delivery fiber is 20 m which is long enough to be used in most of laser processing machines. An output power of 3 kW was achieved at a pump power of 4.23 kW. The slope efficiency was 70%. SRS was able to be suppressed at the same output power by increasing ratio of backward pump power. The SRS level was improved by 5dB when 57% backward pump ratio was adopted compared with the case of 50%. SRS was 35dB below the laser power at the output power of 3 kW even with a 20-m delivery fiber. The M-squared factor was 1.3. Single-mode beam quality was obtained. To evaluate practical utility of the 3 kW single-mode fiber laser, a Bead-on-Plate (BoP) test onto a pure copper plate was executed. The BoP test onto a copper plate was made without stopping or damaging the laser system. That indicates our high power single-mode fiber lasers can be used practically in processing of materials with high reflectivity and high thermal conductivity.

[Gas tamponade following intraoperative pneumothorax on a single lung: A case study].

Science.gov (United States)

El Jaouhari, S D; Mamane Nassirou, O; Meziane, M; Bensghir, M; Haimeur, C

2017-04-01

Intraoperative pneumothorax is a rare complication with a high risk of cardiorespiratory arrest by gas tamponade especially on a single lung. We report the case of a female patient aged 53 years who benefited from a left pneumonectomy on pulmonary tuberculosis sequelae. The patient presented early postoperative anemia with a left hemothorax requiring an emergency thoracotomy. In perioperative, the patient had a gas tamponade following a pneumothorax of the remaining lung, and the fate has been avoided by an exsufflation. Intraoperative pneumothorax can occur due to lesions of the tracheobronchial airway, of the brachial plexus, the placement of a central venous catheter or barotrauma. The diagnosis of pneumothorax during unipulmonary ventilation is posed by the sudden onset of hypoxia associated with increased airway pressures and hypercapnia. The immediate life-saving procedure involves fine needle exsufflation before the placement of a chest tube. Prevention involves reducing the risk of barotrauma by infusing patients with low flow volumes and the proper use of positive airway pressure, knowing that despite protective ventilation, barotraumas risk still exists. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Dynamic variability of the heading-flowering stages of single rice in China based on field observations and NDVI estimations.

Science.gov (United States)

Zhang, Zhao; Song, Xiao; Chen, Yi; Wang, Pin; Wei, Xing; Tao, Fulu

2015-05-01

Although many studies have indicated the consistent impact of warming on the natural ecosystem (e.g., an early flowering and prolonged growing period), our knowledge of the impacts on agricultural systems is still poorly understood. In this study, spatiotemporal variability of the heading-flowering stages of single rice was detected and compared at three different scales using field-based methods (FBMs) and satellite-based methods (SBMs). The heading-flowering stages from 2000 to 2009 with a spatial resolution of 1 km were extracted from the SPOT/VGT NDVI time series data using the Savizky-Golay filtering method in the areas in China dominated by single rice of Northeast China (NE), the middle-lower Yangtze River Valley (YZ), the Sichuan Basin (SC), and the Yunnan-Guizhou Plateau (YG). We found that approximately 52.6 and 76.3 % of the estimated heading-flowering stages by a SBM were within ±5 and ±10 days estimation error (a root mean square error (RMSE) of 8.76 days) when compared with those determined by a FBM. Both the FBM data and the SBM data had indicated a similar spatial pattern, with the earliest annual average heading-flowering stages in SC, followed by YG, NE, and YZ, which were inconsistent with the patterns reported in natural ecosystems. Moreover, diverse temporal trends were also detected in the four regions due to different climate conditions and agronomic factors such as cultivar shifts. Nevertheless, there were no significant differences (p > 0.05) between the FBM and the SBM in both the regional average value of the phenological stages and the trends, implying the consistency and rationality of the SBM at three scales.

Evaluation of single-stage adjustable strabismus surgery under conscious sedation

Directory of Open Access Journals (Sweden)

Sharma Pradeep

2009-01-01

Full Text Available Purpose: To evaluate the feasibility and stability of ocular alignment after single-stage adjustable strabismus surgery (SSASS performed under topical anesthesia. Materials and Methods: Forty-five patients of concomitant exodeviations were randomized into three groups of 15 cases each and were operated with three different techniques: Group I - conventional surgery, Group II - two-stage adjustable suture technique with suture adjustment performed 6h postoperatively and Group III- SSASS under topical anesthesia and intravenous conscious sedation with midazolam and fentanyl. Intraoperative suture adjustment was done by giving a cross target to the patient on the ceiling at the end of the procedure. Surgical results were compared among the three groups at three months follow-up. Intraoperative hemodynamic parameters and patients′ experience of the surgery (by questionnaire were also compared. Results: Mean preoperative deviation for distance in Groups I, II, III was -41.67 prism diopter (pd ±9.0, -38.93 pd ±11.05 and -41.87 pd ±8.91 ( P =0.6 respectively. At three months, mean correction achieved for distance was +31.87 pd ±11.71, +35.47 pd ±10.86 and +42.80 pd ±10.71 respectively which was significantly different between Group III and Group I ( P =0.03. Intraoperatively all hemodynamic parameters remained stable and comparable ( P =0. 5 in all groups. Intraoperative pain ( P < 0.001 and time taken for surgery ( P < 0.001 was more in the SSASS group. Amount of exodrift was 10-12 pd, comparable in all three groups ( P = 0.5. Conclusions: SSASS, performed under topical anesthesia, is safe and has better outcomes than conventional recession-resection surgery for concomitant exodeviation. An overcorrection of about 10-12 pd is recommended to check the exodrift and achieve stable alignment.

Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

Science.gov (United States)

Azizi, Mohammad Ali; Brouwer, Jacob

2017-10-01

A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

Method of independently operating a group of stages within a diffusion cascade

International Nuclear Information System (INIS)

Benedict, M.; Allen, J.F.; Levey, H.B.

1976-01-01

A method of operating a group of the diffusion stages of a productive diffusion cascade with counter-current flow is described. The group consists of a top and a bottom stage which isolates the group from the cascade. The diffused gas produced in the top stage is circulated to the feed of the bottom stage, while at the same time undiffused gas from the bottom stage is circulated to the feed of the top stage whereby major changes in inventory distribution within the group of stages are prevented

Heat transfer characteristics around a single heated rod immersed in sodium pool with gas jet injection

International Nuclear Information System (INIS)

Hideto Niikura; Kazuo Soga; Ken-ichiro Sugiyama; Akira Yamaguchi

2005-01-01

In a steam generator using liquid sodium, water intensely reacts with sodium when it leaks out from a heat transfer tube. It is important to evaluate the influence of sodium-water reaction to surrounding tubes and the shell. Hence, it has been desired to develop the simulation code for the evaluation of sodium-water reaction. From this viewpoint, the Japan Nuclear Cycle is now developing the SERAPHIM code. We reported a preliminary study to establish an experimental method for a single heated rod immersed in sodium pool with steam jet impingement planned in the near future as well as to obtain a preliminary data to verify the adequacy of SERAPHIM code. We first measured local and mean heat transfer coefficients around a horizontal single heated rod immersed in a water pool and a sodium pool with a limited volume in the experimental apparatus. It was confirmed that the mean heat transfer coefficients fairly agreed with the existing data for natural convection in water and sodium. Secondary we measured local and mean heat transfer coefficients around a horizontal single heated rod with Ar gas jet impingement immersed in the limited water pool and in the limited sodium pool. It was clearly observed that the local heat transfer coefficients in the sodium pool keep almost the same values in every angle regardless of increase in Ar gas jet velocity varied from about 8.7m/s to about 78m/s. On the other hand, it was confirmed in the water pool that local heat transfer coefficients on the forward stagnation side exposed in the Ar gas jet impingement increase with increasing the jet velocity while the local heat transfer coefficients on the opposite surface keep almost same values regardless of increase in the velocity. (authors)

Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

DEFF Research Database (Denmark)

Lieke, Kirsten Inga; Rosenørn, Thomas; Pedersen, Jannik

2013-01-01

microscopy (TEM) grids on two stages. Micro- and nanostructural characteristics of sin-gle particles were studied by TEM. Image analysis was carried out on overview and high-resolution images, revealing influence of the exhaust gas treatment (scrubber) on the particle morphology and mixing state. Soot......This work provides insight into the morphology and mixing state of submicron particles in diesel exhaust from a ship engine with an exhaust gas recirculation scrubber. Particles from this low-speed ship engine on test bed were collected using a microiner-tial impactor with transmission electron...

Estimation of bias with the single-zone assumption in measurement of residential air exchange using the perfluorocarbon tracer gas method.

Science.gov (United States)

Van Ryswyk, K; Wallace, L; Fugler, D; MacNeill, M; Héroux, M È; Gibson, M D; Guernsey, J R; Kindzierski, W; Wheeler, A J

2015-12-01

Residential air exchange rates (AERs) are vital in understanding the temporal and spatial drivers of indoor air quality (IAQ). Several methods to quantify AERs have been used in IAQ research, often with the assumption that the home is a single, well-mixed air zone. Since 2005, Health Canada has conducted IAQ studies across Canada in which AERs were measured using the perfluorocarbon tracer (PFT) gas method. Emitters and detectors of a single PFT gas were placed on the main floor to estimate a single-zone AER (AER(1z)). In three of these studies, a second set of emitters and detectors were deployed in the basement or second floor in approximately 10% of homes for a two-zone AER estimate (AER(2z)). In total, 287 daily pairs of AER(2z) and AER(1z) estimates were made from 35 homes across three cities. In 87% of the cases, AER(2z) was higher than AER(1z). Overall, the AER(1z) estimates underestimated AER(2z) by approximately 16% (IQR: 5-32%). This underestimate occurred in all cities and seasons and varied in magnitude seasonally, between homes, and daily, indicating that when measuring residential air exchange using a single PFT gas, the assumption of a single well-mixed air zone very likely results in an under prediction of the AER. The results of this study suggest that the long-standing assumption that a home represents a single well-mixed air zone may result in a substantial negative bias in air exchange estimates. Indoor air quality professionals should take this finding into consideration when developing study designs or making decisions related to the recommendation and installation of residential ventilation systems. © 2014 Her Majesty the Queen in Right of Canada. Indoor Air published by John Wiley & Sons Ltd Reproduced with the permission of the Minister of Health Canada.

Single Stage To Orbit Minimum Requirements Through Numerical Simulation

Science.gov (United States)

Teixeira, E.

It is widely known that producing a single stage to orbit spacecraft is no easy task. It is also understood that it will be the first steady step towards spacecraft that operate in much the same way as today's airliners. This, in turn is believed to decrease the economical cost of reaching space through more efficient use of a single vehicle and higher launch rates. Space is then open to the common man, either through tourism or as a transportation medium. This paper is yet another study on the physical requirements of a SSTO spacecraft. It will begin with simple assumptions and gradually build up accuracy until reaching the use of a numerical simulation tool, so as to provide the necessary insight into it. The curvature of the Earth, its gravitational field, the exhaust pressure loss and atmospheric drag are a few of the considerations that the simulation takes into account. No attention was give to the actual details of the spacecraft such as propulsion type(s), winged or lifting body (aerodynamics), active or passive cooling (thermodynamics), stability and control. All these subsystems are considered to be included into the construction mass. The drag model is a simple textbook approximation and the propulsion force is given by a hypothetical propellant and engine so as to produce the assumed range of specific impulse. Even the construction mass is supposed to be futuristic so as to reach the lowest specified values. Not only vertical take-off will be simulated but also horizontal launching from altitude (from a towing aircraft, for example). The result of the paper shows the relationship between the construction mass and the specific impulse of a given spacecraft if it is to reach low earth orbit. This paper thus aims at bringing some light to the controversial discussion of how to make these vehicles a reality. The simulation program (Matlab) is available to students.

Enhancing the x-ray output of a single-wire explosion with a gas-puff based plasma opening switch

Science.gov (United States)

Engelbrecht, Joseph T.; Ouart, Nicholas D.; Qi, Niansheng; de Grouchy, Philip W.; Shelkovenko, Tatiana A.; Pikuz, Sergey A.; Banasek, Jacob T.; Potter, William M.; Rocco, Sophia V.; Hammer, David A.; Kusse, Bruce R.; Giuliani, John L.

2018-02-01

We present experiments performed on the 1 MA COBRA generator using a low density, annular, gas-puff z-pinch implosion as an opening switch to rapidly transfer a current pulse into a single metal wire on axis. This gas-puff on axial wire configuration was studied for its promise as an opening switch and as a means of enhancing the x-ray output of the wire. We demonstrate that current can be switched from the gas-puff plasma into the wire, and that the timing of the switch can be controlled by the gas-puff plenum backing pressure. X-ray detector measurements indicate that for low plenum pressure Kr or Xe shots with a copper wire, this configuration can offer a significant enhancement in the peak intensity and temporal distribution of radiation in the 1-10 keV range.

Gas Sensor

KAUST Repository

Luebke, Ryan

2015-01-22

A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

Gas Sensor

KAUST Repository

Luebke, Ryan; Eddaoudi, Mohamed; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Salama, Khaled N.

2015-01-01

A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

Power and efficiency in a regenerative gas-turbine cycle with multiple reheating and intercooling stages

Science.gov (United States)

Calvo Hernández, A.; Roco, J. M. M.; Medina, A.

1996-06-01

Using an improved Brayton cycle as a model, a general analysis accounting for the efficiency and net power output of a gas-turbine power plant with multiple reheating and intercooling stages is presented. This analysis provides a general theoretical tool for the selection of the optimal operating conditions of the heat engine in terms of the compressor and turbine isentropic efficiencies and of the heat exchanger efficiency. Explicit results for the efficiency, net power output, optimized pressure ratios, maximum efficiency, maximum power, efficiency at maximum power, and power at maximum efficiency are given. Among others, the familiar results of the Brayton cycle (one compressor and one turbine) and of the corresponding Ericsson cycle (infinite compressors and infinite turbines) are obtained as particular cases.

MRI-guided single fraction ablative radiotherapy for early-stage breast cancer : a brachytherapy versus volumetric modulated arc therapy dosimetry study

NARCIS (Netherlands)

Charaghvandi, Ramona K; den Hartogh, Mariska D; van Ommen, Anne-Mar L N; de Vries, Wilfred J H; Scholten, Vincent; Moerland, Rien; Philippens, Mariëlle E P; Schokker, Rogier I; van Vulpen, Marco; van Asselen, B; van den Bongard, Desirée H J G

2015-01-01

BACKGROUND AND PURPOSE: A radiosurgical treatment approach for early-stage breast cancer has the potential to minimize the patient's treatment burden. The dosimetric feasibility for single fraction ablative radiotherapy was evaluated by comparing volumetric modulated arc therapy (VMAT) with an

Process for purification of gas mixtures

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, S Z; Letitschevskij, V I; Maergojz, I I; Michailov, L A; Puschkarev, L I

1977-06-23

The process relates to the purification of gas mixtures of N, H, and Ar, or N and H, or N and O which contain CO, CO/sub 2/ and water vapour. Single-stage adsorption occurs under standard pressure at temperatures from -40 to +4/sup 0/C up to the point of CO penetration through the zeolite layer. Zeolite is of type A or X combined with Ca, Na, Ag, Cd, Co, Ni, Mn or a natural zeolite of the type klinoptilolite. Regeneration is achieved at constant temperature and pressure of 1-5x10/sup -1/ Torr or by heating to 120-600/sup 0/C.

The role of the spiracles in gas exchange during development of Samia cynthia (Lepidoptera, Saturniidae).

Science.gov (United States)

Hetz, Stefan K

2007-12-01

Spiracles and the tracheal system of insects allow effective delivery of respiratory gases. During development, holometabolous insects encounter large changes in the functional morphology of gas exchange structures. To investigate changes in respiratory patterns during development, CO2-release was measured in larvae, pre-pupae and pupae of Samia cynthia (Lepidoptera, Saturniidae). Gas exchange patterns showed great variability. Caterpillars had high metabolic rates and released carbon dioxide continuously. Pre-pupae and pupae showed typical discontinuous gas exchange cycles (DGC) at reduced metabolic rates. Changes in gas exchange patterns can partly be explained with low metabolic rates during pupation. Sequential blocking of spiracles in pre-pupae and pupae reduced spiracle conductance with tracheal conductance remaining unaffected. Analysis of gas exchange patterns indicates that caterpillars and pre-pupae use more than 14 spiracles simultaneously while pupae only use 8 to 10 spiracles. Total conductance is not a simple multiple of single spiracles, but may be gradually adaptable to gas exchange demands. Surprisingly, moth pupae showed a DGC if all except one spiracle were blocked. The huge conductance of single spiracles is discussed as a pre-adaptation to high metabolic demands at the beginning and the end of the pupal as well as in the adult stage.

Life-cycle greenhouse gas emissions of shale gas, natural gas, coal, and petroleum.

Science.gov (United States)

Burnham, Andrew; Han, Jeongwoo; Clark, Corrie E; Wang, Michael; Dunn, Jennifer B; Palou-Rivera, Ignasi

2012-01-17

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. It has been debated whether the fugitive methane emissions during natural gas production and transmission outweigh the lower carbon dioxide emissions during combustion when compared to coal and petroleum. Using the current state of knowledge of methane emissions from shale gas, conventional natural gas, coal, and petroleum, we estimated up-to-date life-cycle greenhouse gas emissions. In addition, we developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings that need to be further addressed. Our base case results show that shale gas life-cycle emissions are 6% lower than conventional natural gas, 23% lower than gasoline, and 33% lower than coal. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty whether shale gas emissions are indeed lower than conventional gas. Moreover, this life-cycle analysis, among other work in this area, provides insight on critical stages that the natural gas industry and government agencies can work together on to reduce the greenhouse gas footprint of natural gas.

Metoidioplasty as a single stage sex reassignment surgery in female transsexuals: Belgrade experience.

Science.gov (United States)

Djordjevic, Miroslav L; Stanojevic, Dusan; Bizic, Marta; Kojovic, Vladimir; Majstorovic, Marko; Vujovic, Svetlana; Milosevic, Alexandar; Korac, Gradimir; Perovic, Sava V

2009-05-01

Metoidioplasty represents one of the variants of phalloplasty in female transsexuals. Its main characteristic is that it is a one-stage procedure. It involves lengthening and straightening of hypertrophied clitoris to create a neophallus, urethral lengthening to enable voiding while standing, and scrotal reconstruction with insertion of testicle prostheses. Our aim is to describe our technique and highlight its advantages. Between September 2002 and April 2007, 82 female transsexuals, aged 18-54 years (mean age 31) underwent one-stage metoidioplasty. Clitoris is lengthened and straightened by division of clitoral ligaments and short urethral plate. Urethroplasty is done with combined buccal mucosa graft and genital skin flaps. Scrotum is created from labia majora in which two testicle prostheses are inserted. Simultaneously, female genitalia are removed. Patients' personal satisfaction about sensitivity and length of neophallus, possibility to void in standing position, real length of reconstructed urethra as well as complication rate comparing to other published data. The median follow-up was 32 months (range 14-69). The mean neophallic length was 5.7 cm (range 4-10). Voiding in standing position was reported in all patients, while dribbling and spraying were noticed in 23 cases and solved spontaneously. There were two urethral strictures and seven fistulas that required secondary minor revision. All patients reported preserved sensation and normal postoperative erection. Testicle prostheses rejection was not observed in any of the patients. Metoidioplasty is a single-stage and time-saving procedure. It could be an alternative to total phalloplasty in female transsexuals who do not wish to have sexual intercourse. Also, it represents a first step in cases where additional augmentation phalloplasty is required.

Iodine-125 seed brachytherapy for early stage prostate cancer: a single-institution review

International Nuclear Information System (INIS)

Zuber, Simon; Weiß, Susan; Baaske, Dieter; Schöpe, Michael; Stevens, Simon; Bodis, Stephan; Zwahlen, Daniel R

2015-01-01

We are reporting the five-year biochemical control, toxicity profile and dosimetric parameters using iodine-125 low dose rate brachytherapy (BT) as monotherapy for early stage prostate cancer at a single institution. Between April 2006 and December 2010, 169 men with early stage prostate cancer were treated with BT. Biochemical failure was defined using the Phoenix definition (nadir + 2 ng/mL). Treatment-related morbidities, including urinary, rectal and sexual function, were measured, applying the International Prostate Symptom Score (IPSS), the 7-grade Quality of Life Scale (QoL) and medical status, the International Consultation on Incontinence Modular Questionnaire (ICIQ), the International Index of Erectile Function (IIEF-5) and the Common Terminology Criteria for Adverse Events (CTCAE v4.03). Seed migration and loss, dosimetric parameters and learning effects were also analyzed. Medium follow-up time was 50 months (range, 1–85 months). The five-year biochemical failure rate was 7%. Acute proctitis rates were 19% (grade 1) and 1% (grade 2), respectively. The overall incidence of incontinence was 19% (mild), 16% (moderate) and < 1% (severe). An increase in IPSS ≥ 5 points was detected in 59% of patients, with 38% regaining their baseline. Seed dislocation was found in 24% of patients and correlated with D90 and V100. A learning curve was found for seed migration, D90 and V100. QoL correlated with the general health condition of patient, incontinence symptoms and IPSS. BT for early stage prostate cancer offers excellent five-year biochemical control with low toxicities. QoL aspects are favorable. A learning curve was detected for procedural aspects but its impact on patient relevant endpoints remains inconclusive

ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY

Energy Technology Data Exchange (ETDEWEB)

A. LOPEZ ORTIZ; D.P. HARRISON; F.R. GROVES; J.D. WHITE; S. ZHANG; W.-N. HUANG; Y. ZENG

1998-10-31

a twenty-five-cycle test. The sorbent was exposed for 58 consecutive days to temperatures between 600°C and 800°C and gas atmospheres from highly reducing to highly oxidizing without measurable loss of sulfur capacity or reactivity. In the process analysis phase of this study, a two-stage desulfurization process using cerium sorbent with SO2 regeneration followed by zinc sorbent with dilute O2 regeneration was compared to a single-stage process using zinc sorbent and O2 regeneration with SO2 in the regeneration product gas converted to elemental sulfur using the direct sulfur recovery process (DSRP). Material and energy balances were calculated using the process simulation package PRO/II. Major process equipment was sized and a preliminary economic analysis completed. Sorbent replacement rate, which is determined by the multicycle sorbent durability, was found to be the most significant factor in both processes. For large replacement rates corresponding to average sorbent lifetimes of 250 cycles or less, the single-stage zinc sorbent process with DSRP was estimated to be less costly. However, the cost of the two-stage cerium sorbent process was more sensitive to sorbent replacement rate, and, as the required replacement rate decreased, the economics of the two-stage process improved. For small sorbent replacement rates corresponding to average sorbent lifetimes of 1000 cycles or more, the two-stage cerium process was estimated to be less costly. In the relatively wide middle range of sorbent replacement rates, the relative economics of the two processes depends on other factors such as the unit cost of sorbents, oxygen, nitrogen, and the relative capital costs.

Advanced sulfur control concepts for hot-gas desulfurization technology

International Nuclear Information System (INIS)

Lopez Ortiz, A.; Harrison, D.P.; Groves, F.R.; White, J.D.; Zhang, S.; Huang, W.N.; Zeng, Y.

1998-01-01

twenty-five-cycle test. The sorbent was exposed for 58 consecutive days to temperatures between 600C and 800C and gas atmospheres from highly reducing to highly oxidizing without measurable loss of sulfur capacity or reactivity. In the process analysis phase of this study, a two-stage desulfurization process using cerium sorbent with SO2 regeneration followed by zinc sorbent with dilute O2 regeneration was compared to a single-stage process using zinc sorbent and O2 regeneration with SO2 in the regeneration product gas converted to elemental sulfur using the direct sulfur recovery process (DSRP). Material and energy balances were calculated using the process simulation package PRO/II. Major process equipment was sized and a preliminary economic analysis completed. Sorbent replacement rate, which is determined by the multicycle sorbent durability, was found to be the most significant factor in both processes. For large replacement rates corresponding to average sorbent lifetimes of 250 cycles or less, the single-stage zinc sorbent process with DSRP was estimated to be less costly. However, the cost of the two-stage cerium sorbent process was more sensitive to sorbent replacement rate, and, as the required replacement rate decreased, the economics of the two-stage process improved. For small sorbent replacement rates corresponding to average sorbent lifetimes of 1000 cycles or more, the two-stage cerium process was estimated to be less costly. In the relatively wide middle range of sorbent replacement rates, the relative economics of the two processes depends on other factors such as the unit cost of sorbents, oxygen, nitrogen, and the relative capital costs

Process and device for stage by stage enrichment of deuterium and/or tritium in a material suitable for isotope exchange of deuterium and tritium with hydrogen

International Nuclear Information System (INIS)

Iniotakis, N.; Decken, C.B. von der.

1983-01-01

Water containing deuterium and/or tritium is first introduced into a carrier gas flow and reduced for the stage by stage enrichment of deuterium and/or tritium. A hydrogen partial pressure of a maximum of 100 millibar is set in the carrier gas flow. The carrier gas flow is taken along the primary side of an exchange wall suitable for the permeation of hydrogen, and a further carrier gas flow flows on its secondary side, which contains water or hydrogen. Reaction products formed after isotope exchange of deuterium and/or tritium with hydrogen are removed by the secondary carrier gas flow. (orig./HP) [de

Strengthening power generation efficiency utilizing liquefied natural gas cold energy by a novel two-stage condensation Rankine cycle (TCRC) system

International Nuclear Information System (INIS)

Bao, Junjiang; Lin, Yan; Zhang, Ruixiang; Zhang, Ning; He, Gaohong

2017-01-01

Highlights: • A two-stage condensation Rankine cycle (TCRC) system is proposed. • Net power output and thermal efficiency increases by 45.27% and 42.91%. • The effects of the condensation temperatures are analyzed. • 14 working fluids (such as propane, butane etc.) are compared. - Abstract: For the low efficiency of the traditional power generation system with liquefied natural gas (LNG) cold energy utilization, by improving the heat transfer characteristic between the working fluid and LNG, this paper has proposed a two-stage condensation Rankine cycle (TCRC) system. Using propane as working fluid, compared with the combined cycle in the conventional LNG cold energy power generation method, the net power output, thermal efficiency and exergy efficiency of the TCRC system are respectively increased by 45.27%, 42.91% and 52.31%. Meanwhile, the effects of the first-stage and second-stage condensation temperature and LNG vaporization pressure on the performance and cost index of the TCRC system (net power output, thermal efficiency, exergy efficiency and UA) are analyzed. Finally, using the net power output as the objective function, with 14 organic fluids (such as propane, butane etc.) as working fluids, the first-stage and second-stage condensation temperature at different LNG vaporization pressures are optimized. The results show that there exists a first-stage and second-stage condensation temperature making the performance of the TCRC system optimal. When LNG vaporization pressure is supercritical pressure, R116 has the best economy among all the investigated working fluids, and while R150 and R23 are better when the vaporization pressure of LNG is subcritical.

Safety basis for selected activities in single-shell tanks with flammable gas concerns. Revision 1

International Nuclear Information System (INIS)

Schlosser, R.L.

1996-01-01

This is full revision to Revision 0 of this report. The purpose of this report is to provide a summary of analyses done to support activities performed for single-shell tanks. These activities are encompassed by the flammable gas Unreviewed Safety Question (USQ). The basic controls required to perform these activities involve the identification, elimination and/or control of ignition sources and monitoring for flammable gases. Controls are implemented through the Interim Safety Basis (ISB), IOSRs, and OSDs. Since this report only provides a historical compendium of issues and activities, it is not to be used as a basis to perform USQ screenings and evaluations. Furthermore, these analyses and others in process will be used as the basis for developing the Flammable Gas Topical Report for the ISB Upgrade

Gas hydrate nucleation

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

The overall aim of the project was to gain more knowledge about the kinetics of gas hydrate formation especially the early growth phase. Knowledge of kinetics of gas hydrate formation is important and measurements of gas hydrate particle size and concentration can contribute to improve this knowledge. An experimental setup for carrying out experimental studies of the nucleation and growth of gas hydrates has been constructed and tested. Multi wavelength extinction (MWE) was the experimental technique selected for obtaining particle diameter and concentration. The principle behind MWE is described as well as turbidity spectrum analysis that in an initial stage of the project was considered as an alternative experimental technique. Details of the experimental setup and its operation are outlined. The measuring cell consists of a 1 litre horizontal tube sustaining pressures up to 200 bar. Laser light for particle size determination can be applied through sapphire windows. A description of the various auxiliary equipment and of another gas hydrate cell used in the study are given. A computer program for simulation and analysis of gas hydrate experiments is based on the gas hydrate kinetics model proposed by Skovborg and Rasmussen (1993). Initial measurements showed that knowledge of the refractive index of gas hydrates was important in order to use MWE. An experimental determination of the refractive index of methane and natural gas hydrate is described. The test experiments performed with MWE on collectives of gas hydrate particles and experiments with ethane, methane and natural gas hydrate are discussed. Gas hydrate particles initially seem to grow mainly in size and at latter stages in number. (EG) EFP-94; 41 refs.

Gas hydrate nucleation

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-31

The overall aim of the project was to gain more knowledge about the kinetics of gas hydrate formation especially the early growth phase. Knowledge of kinetics of gas hydrate formation is important and measurements of gas hydrate particle size and concentration can contribute to improve this knowledge. An experimental setup for carrying out experimental studies of the nucleation and growth of gas hydrates has been constructed and tested. Multi wavelength extinction (MWE) was the experimental technique selected for obtaining particle diameter and concentration. The principle behind MWE is described as well as turbidity spectrum analysis that in an initial stage of the project was considered as an alternative experimental technique. Details of the experimental setup and its operation are outlined. The measuring cell consists of a 1 litre horizontal tube sustaining pressures up to 200 bar. Laser light for particle size determination can be applied through sapphire windows. A description of the various auxiliary equipment and of another gas hydrate cell used in the study are given. A computer program for simulation and analysis of gas hydrate experiments is based on the gas hydrate kinetics model proposed by Skovborg and Rasmussen (1993). Initial measurements showed that knowledge of the refractive index of gas hydrates was important in order to use MWE. An experimental determination of the refractive index of methane and natural gas hydrate is described. The test experiments performed with MWE on collectives of gas hydrate particles and experiments with ethane, methane and natural gas hydrate are discussed. Gas hydrate particles initially seem to grow mainly in size and at latter stages in number. (EG) EFP-94; 41 refs.

Life-cycle analysis of shale gas and natural gas.

Energy Technology Data Exchange (ETDEWEB)

Clark, C.E.; Han, J.; Burnham, A.; Dunn, J.B.; Wang, M. (Energy Systems); ( EVS)

2012-01-27

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. Using the current state of knowledge of the recovery, processing, and distribution of shale gas and conventional natural gas, we have estimated up-to-date, life-cycle greenhouse gas emissions. In addition, we have developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps - such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings - that need to be addressed further. Our base case results show that shale gas life-cycle emissions are 6% lower than those of conventional natural gas. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty regarding whether shale gas emissions are indeed lower than conventional gas emissions. This life-cycle analysis provides insight into the critical stages in the natural gas industry where emissions occur and where opportunities exist to reduce the greenhouse gas footprint of natural gas.

An optimal design of cluster spacing intervals for staged fracturing in horizontal shale gas wells based on the optimal SRVs

Directory of Open Access Journals (Sweden)

Lan Ren

2017-09-01

Full Text Available When horizontal well staged cluster fracturing is applied in shale gas reservoirs, the cluster spacing is essential to fracturing performance. If the cluster spacing is too small, the stimulated area between major fractures will be overlapped, and the efficiency of fracturing stimulation will be decreased. If the cluster spacing is too large, the area between major fractures cannot be stimulated completely and reservoir recovery extent will be adversely impacted. At present, cluster spacing design is mainly based on the static model with the potential reservoir stimulation area as the target, and there is no cluster spacing design method in accordance with the actual fracturing process and targets dynamic stimulated reservoir volume (SRV. In this paper, a dynamic SRV calculation model for cluster fracture propagation was established by analyzing the coupling mechanisms among fracture propagation, fracturing fluid loss and stress. Then, the cluster spacing was optimized to reach the target of the optimal SRVs. This model was applied for validation on site in the Jiaoshiba shale gasfield in the Fuling area of the Sichuan Basin. The key geological engineering parameters influencing the optimal cluster spacing intervals were analyzed. The reference charts for the optimal cluster spacing design were prepared based on the geological characteristics of south and north blocks in the Jiaoshiba shale gasfield. It is concluded that the cluster spacing optimal design method proposed in this paper is of great significance in overcoming the blindness in current cluster perforation design and guiding the optimal design of volume fracturing in shale gas reservoirs. Keywords: Shale gas, Horizontal well, Staged fracturing, Cluster spacing, Reservoir, Stimulated reservoir volume (SRV, Mathematical model, Optimal method, Sichuan basin, Jiaoshiba shale gasfield

High-BTU gas production from tar-bearing hot coke oven gas over iron catalyst

Energy Technology Data Exchange (ETDEWEB)

L.Y. Li; K. Morishita; T. Takarada [Gunma University, Gunma (Japan). Department of Biological and Chemical Engineering

2005-07-01

To utilize the tar-bearing hot coke oven gas (the by-product of coke making process) more effectively, a process was developed by converting the hot coke oven gas into a methane rich high-BTU gas over iron-bearing catalysts. The catalytic behaviour of Indonesian limonite ore was mainly discussed. For a reference, a conventional nickel catalyst (Ni/Al{sub 2}O{sub 3}) was employed. Laboratory scale tests were carried out in a two-stage fixed-bed reactor at ambient pressure. A bituminous coal sample was heated at first stage, the volatiles was carried by feed gas and decomposed at second stage. The limonite promoted hydropyrolysis of coal volatiles similar to Ni/Al{sub 2}O{sub 3} catalyst. High yields of total product gas and methane were obtained at 50 vol.% hydrogen atmosphere with a feed gas of 60 ml min{sup -1} hydrogen and 60 ml min{sup -1} nitrogen. After experiments, hydrocarbons heavier than ethane were not observed. Also that, carbon balance was more than 99.8% in coal char, product gases and carbon deposits. It was considered that coal volatiles converted into light gases and carbon almost completely in catalyst bed. Yields of product gas and methane depended upon catalytic temperature. At 923 K, the maximum yield of product gas was achieved at 74.3% for limonite catalyst on carbon balance with methane 83.2 vol.% of the carbonaceous gas products. Comparing with limonite, Fe/Al{sub 2}O{sub 3} and BOF dust samples showed low activities on coal volatiles catalytic decomposition. 21 refs., 5 figs., 3 tabs.

Two-step two-stage fission gas release model

International Nuclear Information System (INIS)

Kim, Yong-soo; Lee, Chan-bock

2006-01-01

Based on the recent theoretical model, two-step two-stage model is developed which incorporates two stage diffusion processes, grain lattice and grain boundary diffusion, coupled with the two step burn-up factor in the low and high burn-up regime. FRAPCON-3 code and its in-pile data sets have been used for the benchmarking and validation of this model. Results reveals that its prediction is in better agreement with the experimental measurements than that by any model contained in the FRAPCON-3 code such as ANS 5.4, modified ANS5.4, and Forsberg-Massih model over whole burn-up range up to 70,000 MWd/MTU. (author)

Quantification of regional early stage gas exchange changes using hyperpolarized {sup 129}Xe MRI in a rat model of radiation-induced lung injury

Energy Technology Data Exchange (ETDEWEB)

Doganay, Ozkan, E-mail: ozkan.doganay@oncology.ox.ac.uk [Department of Medical Biophysics, Western University, London, Ontario N6A5C1 (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario N6A5C1 (Canada); Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom); Stirrat, Elaine [Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G1X8 (Canada); McKenzie, Charles [Department of Medical Biophysics, Western University, London, Ontario N6A5C1 (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario N6A5C1 (Canada); Schulte, Rolf F. [General Electric Global Research, Munich 85748 (Germany); Santyr, Giles E. [Department of Medical Biophysics, Western University, London, Ontario N6A5C1 (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario N6A5C1 (Canada); Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G1X8 (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G1L7 (Canada)

2016-05-15

Purpose: To assess the feasibility of hyperpolarized (HP) {sup 129}Xe MRI for detection of early stage radiation-induced lung injury (RILI) in a rat model involving unilateral irradiation by assessing differences in gas exchange dynamics between irradiated and unirradiated lungs. Methods: The dynamics of gas exchange between alveolar air space and pulmonary tissue (PT), PT and red blood cells (RBCs) was measured using single-shot spiral iterative decomposition of water and fat with echo asymmetry and least-squares estimation images of the right and left lungs of two age-matched cohorts of Sprague Dawley rats. The first cohort (n = 5) received 18 Gy irradiation to the right lung using a {sup 60}Co source and the second cohort (n = 5) was not irradiated and served as the healthy control. Both groups were imaged two weeks following irradiation when radiation pneumonitis (RP) was expected to be present. The gas exchange data were fit to a theoretical gas exchange model to extract measurements of pulmonary tissue thickness (L{sub PT}) and relative blood volume (V{sub RBC}) from each of the right and left lungs of both cohorts. Following imaging, lung specimens were retrieved and percent tissue area (PTA) was assessed histologically to confirm RP and correlate with MRI measurements. Results: Statistically significant differences in L{sub PT} and V{sub RBC} were observed between the irradiated and non-irradiated cohorts. In particular, L{sub PT} of the right and left lungs was increased approximately 8.2% and 5.0% respectively in the irradiated cohort. Additionally, V{sub RBC} of the right and left lungs was decreased approximately 36.1% and 11.7% respectively for the irradiated cohort compared to the non-irradiated cohort. PTA measurements in both right and left lungs were increased in the irradiated group compared to the non-irradiated cohort for both the left (P < 0.05) and right lungs (P < 0.01) confirming the presence of RP. PTA measurements also correlated with the

Dynamic design of gas sorption J-T refrigerator

International Nuclear Information System (INIS)

Chan, C.K.

1986-01-01

A long-life Joule-Thomson refrigerator which is heat powered, involves no sealing, and has few mechanical parts and is desirable for longterm sensor cooling in space. In the gas-sorption J-T refrigerator, cooling is achieved by gas sorption (either adsorption or absorption) processes. Currently, a modular, single-stage refrigerator is being designed and built to be operated at 20 K. The design was analyzed using a dynamic model, which is described here. The model includes the kinetics of the compressors and the heat switches, the heat transfer of the pre-coolers and the heat exchangers, the on/off ratio of the check valves, and the impedance of the J-T valve. The cooling power, the cycle time, and the operating conditions were obtained in terms of the power input, the heat sink temperature, and the J-T impedance

Dynamic design of gas sorption J-T refrigerator

Science.gov (United States)

Chan, C. K.

1986-01-01

A long-life Joule-Thomson refrigerator which is heat powered, involves no sealing, and has few mechanical parts is desirable for long-term sensor cooling in space. In the gas-sorption J-T refrigerator, cooling is achieved by gas sorption (either adsorption or absorption) processes. Currently, a modular, single-stage refrigerator is being designed and built to be operated at 20 K. The design was analyzed using a dynamic model, which is described here. The model includes the kinetics of the compressors and the heat switches, the heat transfer of the pre-coolers and the heat exchangers, the on/off ratio of the check valves, and the impedance of the J-T valve. The cooling power, the cycle time, and the operating conditions were obtained in terms of the power input, the heat sink temperature, and the J-T impedance.

Single-stage accelerator mass spectrometer radiocarbon-interference identification and positive-ionisation characterisation

Energy Technology Data Exchange (ETDEWEB)

Wilcken, K.M., E-mail: klaus.wilcken@ansto.gov.au [Scottish Universities Environmental Research Centre, Scottish Enterprise Technology Park, East Kilbride G75 0QF (United Kingdom); Freeman, S.P.H.T.; Xu, S.; Dougans, A. [Scottish Universities Environmental Research Centre, Scottish Enterprise Technology Park, East Kilbride G75 0QF (United Kingdom)

2013-01-15

A single-stage accelerator mass spectrometer (SSAMS) is a good alternative to conventional spectrometers based on tandem electrostatic acceleration for radiocarbon measurement and permits experimentation with both negative and positive carbon ions. However, such {sup 14}C AMS of either polarity ions is limited by an interference. In the case of anion acceleration we have newly determined this to be summed {sup 13}C and {sup 16}O by improvising an additional Wien filter on our SSAMS deck. Also, {sup 14}C AMS might be improved by removing its dependency on negative-ionisation in a sputter ion source. This requires negative-ionisation of sample atoms elsewhere to suppress the {sup 14}N interference, which we accomplish by transmitting initially positive ions through a thin membrane. The ionisation dependence on ion-energy is found to be consistent with previous experimentation with vapours and thicker foils.

Single-gene prognostic signatures for advanced stage serous ovarian cancer based on 1257 patient samples.

Science.gov (United States)

Zhang, Fan; Yang, Kai; Deng, Kui; Zhang, Yuanyuan; Zhao, Weiwei; Xu, Huan; Rong, Zhiwei; Li, Kang

2018-04-16

We sought to identify stable single-gene prognostic signatures based on a large collection of advanced stage serous ovarian cancer (AS-OvCa) gene expression data and explore their functions. The empirical Bayes (EB) method was used to remove the batch effect and integrate 8 ovarian cancer datasets. Univariate Cox regression was used to evaluate the association between gene and overall survival (OS). The Database for Annotation, Visualization and Integrated Discovery (DAVID) tool was used for the functional annotation of genes for Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The batch effect was removed by the EB method, and 1257 patient samples were used for further analysis. We selected 341 single-gene prognostic signatures with FDR matrix organization, focal adhesion and DNA replication which are closely associated with cancer. We used the EB method to remove the batch effect of 8 datasets, integrated these datasets and identified stable prognosis signatures for AS-OvCa.

Lifecycle analysis of renewable natural gas and hydrocarbon fuels from wastewater treatment plants’ sludge

Energy Technology Data Exchange (ETDEWEB)

Lee, Uisung [Argonne National Lab. (ANL), Argonne, IL (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Urgun Demirtas, Meltem [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Tao, Ling [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-09-01

Wastewater treatment plants (WWTPs) produce sludge as a byproduct when they treat wastewater. In the United States, over 8 million dry tons of sludge are produced annually just from publicly owned WWTPs. Sludge is commonly treated in anaerobic digesters, which generate biogas; the biogas is then largely flared to reduce emissions of methane, a potent greenhouse gas. Because sludge is quite homogeneous and has a high energy content, it is a good potential feedstock for other conversion processes that make biofuels, bioproducts, and power. For example, biogas from anaerobic digesters can be used to generate renewable natural gas (RNG), which can be further processed to produce compressed natural gas (CNG) and liquefied natural gas (LNG). Sludge can be directly converted into hydrocarbon liquid fuels via thermochemical processes such as hydrothermal liquefaction (HTL). Currently, the environmental impacts of converting sludge into energy are largely unknown, and only a few studies have focused on the environmental impacts of RNG produced from existing anaerobic digesters. As biofuels from sludge generate high interest, however, existing anaerobic digesters could be upgraded to technology with more economic potential and more environmental benefits. The environmental impacts of using a different anaerobic digestion (AD) technology to convert sludge into energy have yet to be analyzed. In addition, no studies are available about the direct conversion of sludge into liquid fuels. In order to estimate the energy consumption and greenhouse gas (GHG) emissions impacts of these alternative pathways (sludge-to-RNG and sludge-to-liquid), this study performed a lifecycle analysis (LCA) using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model. The energy uses and GHG emissions associated with the RNG and hydrocarbon liquid are analyzed relative to the current typical sludge management case, which consists of a single-stage mesophilic

Effects of Hot Streak Shape on Rotor Heating in a High-Subsonic Single-Stage Turbine

Science.gov (United States)

Dorney, Daniel J.; Gundy-Burlet, Karen L.; Norvig, Peter (Technical Monitor)

1999-01-01

Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location (clocking) of the hot streak relative to the first-stage vane airfoils can be used to minimize the adverse effects of the hot streak. The effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils have also been evaluated. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine operating in high subsonic flow. In addition to a simulation of the baseline turbine, simulations have been performed for circular and elliptical hot streaks of varying sizes in an effort to represent different combustor designs. The predicted results for the baseline simulation show good agreement with the available experimental data. The results of the hot streak simulations indicate: that a) elliptical hot streaks mix more rapidly than circular hot streaks, b) for small hot streak surface area the average rotor temperature is not a strong function of hot streak temperature ratio or shape, and c) hot streaks with larger surface area interact with the secondary flows at the rotor hub endwall, generating an additional high temperature region.

Evaluation of Water Injection Effect on NO(x) Formation for a Staged Gas Turbine Combustor

Science.gov (United States)

Fan, L.; Yang, S. L.; Kundu, K. P.

1996-01-01

NO(x) emission control by water injection on a staged turbine combustor (STC) was modeled using the KIVA-2 code with modification. Water is injected into the rich-burn combustion zone of the combustor by a single nozzle. Parametric study for different water injection patterns was performed. Results show NO(x) emission will decrease after water being injected. Water nozzle location also has significant effect for NO formation and fuel ignition. The chemical kinetic model is also sensitive to the excess water. Through this study, a better understanding of the physics and chemical kinetics is obtained, this will enhance the STC design process.

Experimental Research on the Impactive Dynamic Effect of Gas-Pulverized Coal of Coal and Gas Outburst

Directory of Open Access Journals (Sweden)

Haitao Sun

2018-03-01

Full Text Available Coal and gas outburst is one of the major serious natural disasters during underground coal, and the shock air flow produced by outburst has a huge threat on the mine safety. In order to study the two-phase flow of a mixture of pulverized coal and gas of a mixture of pulverized coal and gas migration properties and its shock effect during the process of coal and gas outburst, the coal samples of the outburst coal seam in Yuyang Coal Mine, Chongqing, China were selected as the experimental subjects. By using the self-developed coal and gas outburst simulation test device, we simulated the law of two-phase flow of a mixture of pulverized coal and gas in the roadway network where outburst happened. The results showed that the air in the roadway around the outburst port is disturbed by the shock wave, where the pressure and temperature are abruptly changed. For the initial gas pressure of 0.35 MPa, the air pressure in different locations of the roadway fluctuated and eventually remain stable, and the overpressure of the outburst shock wave was about 20~35 kPa. The overpressure in the main roadway and the distance from the outburst port showed a decreasing trend. The highest value of temperature in the roadway increased by 0.25 °C and the highest value of gas concentration reached 38.12% during the experiment. With the action of shock air flow, the pulverized coal transportation in the roadway could be roughly divided into three stages, which are the accelerated movement stage, decelerated movement stage and the particle settling stage respectively. Total of 180.7 kg pulverized coal of outburst in this experiment were erupted, and most of them were accumulated in the main roadway. Through the analysis of the law of outburst shock wave propagation, a shock wave propagation model considering gas desorption efficiency was established. The relationships of shock wave overpressure and outburst intensity, gas desorption rate, initial gas pressure, cross

Development and testing of a two stage granular filter to improve collection efficiency

Energy Technology Data Exchange (ETDEWEB)

Rangan, R.S.; Prakash, S.G.; Chakravarti, S.; Rao, S.R.

1999-07-01

A circulating bed granular filter (CBGF) with a single filtration stage was tested with a PFB combustor in the Coal Research Facility of BHEL R and D in Hyderabad during the years 1993--95. Filter outlet dust loading varied between 20--50 mg/Nm{sup 3} for an inlet dust loading of 5--8 gms/Nm{sup 3}. The results were reported in Fluidized Bed Combustion-Volume 2, ASME 1995. Though the outlet consists of predominantly fine particulates below 2 microns, it is still beyond present day gas turbine specifications for particulate concentration. In order to enhance the collection efficiency, a two-stage granular filtration concept was evolved, wherein the filter depth is divided between two stages, accommodated in two separate vertically mounted units. The design also incorporates BHEL's scale-up concept of multiple parallel stages. The two-stage concept minimizes reentrainment of captured dust by providing clean granules in the upper stage, from where gases finally exit the filter. The design ensures that dusty gases come in contact with granules having a higher dust concentration at the bottom of the two-stage unit, where most of the cleaning is completed. A second filtration stage of cleaned granules is provided in the top unit (where the granules are returned to the system after dedusting) minimizing reentrainment. Tests were conducted to determine the optimum granule to dust ratio (G/D ratio) which decides the granule circulation rate required for the desired collection efficiency. The data brings out the importance of pre-separation and the limitation on inlet dust loading for any continuous system of granular filtration. Collection efficiencies obtained were much higher (outlet dust being 3--9 mg/Nm{sub 3}) than in the single stage filter tested earlier for similar dust loading at the inlet. The results indicate that two-stage granular filtration has a high potential for HTHT application with fewer risks as compared to other systems under development.

A Single-Stage LED Tube Lamp Driver with Power-Factor Corrections and Soft Switching for Energy-Saving Indoor Lighting Applications

Directory of Open Access Journals (Sweden)

Chun-An Cheng

2017-01-01

Full Text Available This paper presents a single-stage alternating current (AC/direct current (DC light-emitting diode (LED tube lamp driver for energy-saving indoor lighting applications; this driver features power-factor corrections and soft switching, and also integrates a dual buck-boost converter with coupled inductors and a half-bridge series resonant converter cascaded with a bridge rectifier into a single-stage power-conversion topology. The features of the presented driver are high efficiency (>91%, satisfying power factor (PF > 0.96, low input-current total-harmonic distortion (THD < 10%, low output voltage ripple factor (<7.5%, low output current ripple factor (<8%, and zero-voltage switching (ZVS obtained on both power switches. Operational principles are described in detail, and experimental results obtained from an 18 W-rated LED tube lamp for T8/T10 fluorescent lamp replacements with input utility-line voltages ranging from 100 V to 120 V have demonstrated the functionality of the presented driver suitable for indoor lighting applications.

A national assessment of underground natural gas storage: identifying wells with designs likely vulnerable to a single-point-of-failure

Science.gov (United States)

Michanowicz, Drew R.; Buonocore, Jonathan J.; Rowland, Sebastian T.; Konschnik, Katherine E.; Goho, Shaun A.; Bernstein, Aaron S.

2017-05-01

The leak of processed natural gas (PNG) from October 2015 to February 2016 from the Aliso Canyon storage facility, near Los Angeles, California, was the largest single accidental release of greenhouse gases in US history. The Interagency Task Force on Natural Gas Storage Safety and California regulators recently recommended operators phase out single-point-of-failure (SPF) well designs. Here, we develop a national dataset of UGS well activity in the continental US to assess regulatory data availability and uncertainty, and to assess the prevalence of certain well design deficiencies including single-point-of-failure designs. We identified 14 138 active UGS wells associated with 317 active UGS facilities in 29 states using regulatory and company data. State-level wellbore datasets contained numerous reporting inconsistencies that limited data concatenation. We identified 2715 active UGS wells across 160 facilities that, like the failed well at Aliso Canyon, predated the storage facility, and therefore were not originally designed for gas storage. The majority (88%) of these repurposed wells are located in OH, MI, PA, NY, and WV. Repurposed wells have a median age of 74 years, and the 2694 repurposed wells constructed prior to 1979 are particularly likely to exhibit design-related deficiencies. An estimated 210 active repurposed wells were constructed before 1917—before cement zonal isolation methods were utilized. These wells are located in OH, PA, NY, and WV and represent the highest priority related to potential design deficiencies that could lead to containment loss. This national baseline assessment identifies regulatory data uncertainties, highlights a potentially widespread vulnerability of the natural gas supply chain, and can aid in prioritization and oversight for high-risk wells and facilities.

Radial compressor for a two-stage heat pump. Phase 2; Compresseur radial pour pompe a chaleur bi-etagee. Phase 2

Energy Technology Data Exchange (ETDEWEB)

Schiffmann, J.; Favrat, D. [Federal Institute of Technology (EPFL), Industrial Energy Systems Laboratory (LENI), Lausanne (Switzerland); Molyneaux, A. [Ofttech SA, Lausanne (Switzerland)

2005-07-01

This final report for the Swiss Federal Office of Energy (SFOE) reviews the results of the second phase of a project carried out at the Federal Institute of Technology in Lausanne, Switzerland, that involved the development of a two-stage heat pump that could replace conventional sources of domestic heating such as oil or gas-fired boilers. This report deals with the construction of a single-stage system to test the basic functions, aerodynamic bearings, drive and compressor and thus prove the correctness of the concept of the system. The results of the tests made are presented and discussed.

Hydrodynamic performance of a single-use aerated stirred bioreactor in animal cell culture: applications of tomography, dynamic gas disengagement (DGD), and CFD.

Science.gov (United States)

Kazemzadeh, Argang; Elias, Cynthia; Tamer, Melih; Ein-Mozaffari, Farhad

2018-05-01

The hydrodynamics of gas-liquid two-phase flow in a single-use bioreactor were investigated in detail both experimentally and numerically. Electrical resistance tomography (ERT) and dynamic gas disengagement (DGD) combined with computational fluid dynamics (CFD) were employed to assess the effect of the volumetric gas flow rate and impeller speed on the gas-liquid flow field, local and global gas holdup values, and Sauter mean bubble diameter. From the results obtained from DGD coupled with ERT, the bubble sizes were determined. The experimental data indicated that the total gas holdup values increased with increasing both the rotational speed of impeller and volumetric gas flow rate. Moreover, the analysis of the flow field generated inside the aerated stirred bioreactor was conducted using CFD results. Overall, a more uniform distribution of the gas holdup was obtained at impeller speeds ≥ 100 rpm for volumetric gas flow rates ≥ 1.6 × 10 -5  m 3 /s.

Simultaneous specimen and stage cleaning device for analytical electron microscope

Science.gov (United States)

Zaluzec, Nestor J.

1996-01-01

An improved method and apparatus are provided for cleaning both a specimen stage, a specimen and an interior of an analytical electron microscope (AEM). The apparatus for cleaning a specimen stage and specimen comprising a plasma chamber for containing a gas plasma and an air lock coupled to the plasma chamber for permitting passage of the specimen stage and specimen into the plasma chamber and maintaining an airtight chamber. The specimen stage and specimen are subjected to a reactive plasma gas that is either DC or RF excited. The apparatus can be mounted on the analytical electron microscope (AEM) for cleaning the interior of the microscope.

COOLING STAGES OF CRYOGENIC SYSTEMS

OpenAIRE

Троценко, А. В.

2011-01-01

The formalized definition for cooling stage of low temperature system is done. Based on existing information about the known cryogenic unit cycles the possible types of cooling stages are single out. From analyses of these stages their classification by various characteristics is suggested. The results of thermodynamic optimization of final throttle stage of cooling, which are used as working fluids helium, hydrogen and nitrogen, are shown.

In vivo effect of single oral dose of artemether against early juvenile stages of Schistosoma mansoni Egyptian strain.

Science.gov (United States)

El-Beshbishi, Samar N; Taman, Amira; El-Malky, Mohamed; Azab, Manar S; El-Hawary, Amira K; El-Tantawy, Dina A

2013-10-01

The current treatment and control of schistosomiasis, rely on a single drug, praziquantel, although, it has minor activity against juvenile stages of the parasite. Studies have shown that artemether (ART) exhibits effects against juveniles of Schistosoma mansoni Liberian and Puerto Rican strains, Schistosoma japonicum and Schistosoma haematobium. Aiming to assess the in vivo activity of single oral dose of ART against early juvenile stages of S. mansoni Egyptian strain, this study was established. Mice were treated with ART (400 mg/kg) at two time points evenly spaced over the period of larval development (7 and 21 days post-infection; pi), and a third treatment point (day 49 pi) was included to elucidate when susceptibility decreases. Administration of ART on day 7 pi reduced the total worm burden by 85.94%. The greatest reductions were seen when treatment was given on day 21 pi, with total and female worm burden reductions of 91.52% and 90.57%, respectively, and cessation of oviposition. Similar dose given on day 49 pi reduced total worm burden by 55.17% and female worm burden by 66.51%. Moreover, it induced significant reduction in the tissue egg load and significant alterations in the oogram pattern with decreased immature eggs and increased dead eggs. Antipathological activities were evident in significant reductions in granulomata count and diameter. In conclusion, ART exhibits major in vivo schistosomicidal effects against the early larval migratory stages of S. mansoni Egyptian strain, mainly the 21-day old schistosomula, hence preventing disease progression and morbidity. Copyright © 2013 Elsevier Inc. All rights reserved.

Design and construction of a single unit multi-function optical encoder for a six-degree-of-freedom motion error measurement in an ultraprecision linear stage

International Nuclear Information System (INIS)

Lee, ChaBum; Kim, Gyu Ha; Lee, Sun-Kyu

2011-01-01

This paper presents the method of a six-degree-of-freedom (DOF) posture measurement in a linear stage by employing a single unit of an optical encoder. The proposed optical encoder was constructed to simultaneously measure the posture along the traveling axis; angular errors, pitch, yaw and roll; and translational errors, ΔX, ΔY and ΔZ. It consists of a diffractive optical element, a corner cube, four separate two-dimensional position-sensitive detectors, four photodiodes and auxiliary optics components. The circularly polarizing interferometric technique was integrated to measure the displacement of the stage along the traveling axis in a robust manner and the resolution was estimated to be less than 0.4 nm. Two types of stages were employed for the measurement implementation, the piezoelectric transducer-driven and the ballscrew-driven, and they were feedback-controlled for the traveling axis, respectively. With a single travel of the stage, it provided a six-DOF motion error with a high resolution, less than 0.03 arcsec, 20 nm and 0.4 nm for angular errors, ΔY and ΔZ, and ΔX, respectively, at the same time. As a result, it was seen that motion errors of the stage have relevance to the driving mechanism and the whole construction of the stage

Outcomes of single-stage total arch replacement via clamshell incision

Directory of Open Access Journals (Sweden)

Ishizaka Toru

2011-09-01

Full Text Available Abstract Background Treatment of complex aortic pathologies involving the transverse arch with extensive involvement of the descending aorta remains a surgical challenge. Since clamshell incision provides superior exposure of the entire thoracic aorta, we evaluated the use of this technique for single-stage total arch replacement by arch vessel reconstruction. Methods The arch-first technique combined with clamshell incision was used in 38 cases of aneurysm and aortic disease in 2008 and 2009. Extensive total arch replacement was used with clamshell incision for reconstruction of arch vessels under deep hypothermic circulatory arrest. Results Overall 30-day mortality was 13%. The mean operating time was approximately 8 hours. Deep hypothermia resulted in mean CPB time exceeding 4.5 hours and mean duration of circulatory arrest was 25 minutes. The overall postoperative temporary and permanent neurologic dysfunction rates were 3% and 3% for elective and 3% and 0% for emergency surgery, respectively. All patients except the five who died in hospital were discharged without nursing care after an average post-operative hospital stay of 35 days. Conclusions The arch-first technique, combined with clamshell incision, provides expeditious replacement of the thoracic aorta with an acceptable duration of hypothermic circulatory arrest and minimizes the risk of retrograde atheroembolism by using antegrade perfusion.

Comparison of alternative flue gas dry treatment technologies in waste-to-energy processes.

Science.gov (United States)

Dal Pozzo, Alessandro; Antonioni, Giacomo; Guglielmi, Daniele; Stramigioli, Carlo; Cozzani, Valerio

2016-05-01

Acid gases such as HCl and SO2 are harmful both for human health and ecosystem integrity, hence their removal is a key step of the flue gas treatment of Waste-to-Energy (WtE) plants. Methods based on the injection of dry sorbents are among the Best Available Techniques for acid gas removal. In particular, systems based on double reaction and filtration stages represent nowadays an effective technology for emission control. The aim of the present study is the simulation of a reference two-stage (2S) dry treatment system performance and its comparison to three benchmarking alternatives based on single stage sodium bicarbonate injection. A modelling procedure was applied in order to identify the optimal operating configuration of the 2S system for different reference waste compositions, and to determine the total annual cost of operation. Taking into account both operating and capital costs, the 2S system appears the most cost-effective solution for medium to high chlorine content wastes. A Monte Carlo sensitivity analysis was carried out to assess the robustness of the results. Copyright © 2016. Published by Elsevier Ltd.

Early stage of deformation in tungsten, tantalum, and nickel single crystals

International Nuclear Information System (INIS)

Pinatti, D.G.

1977-01-01

High purity Tantalum, Tungsten and Nickel single crystals were tested in simple tension between 77 and 300 K. The Ta and W was oriented for maximum resolved shear stress on the [111] (101) system. Simultaneously microstrain and ultrasonic propagation measurements (attenuation and modulus defect) were performed at various stress bias in order to test details of theories concerning the preyield region and the flow stress in body-centered cubic refractory metals. The experimental retical predictions for the kink chain model over the string model for dislocation. It appears that double kink nucleation in non-screw dislocations has negligible effect in this domains. The results for annealed Ta exhibited no stress bias effect on the ultrasonic propagation measurements, which suggest that the strong influence of impurities mask our ability to discern this fine structure for dislocation motion. For prestrained W and Ta, it was found that double-kink nucleation on nonscrew dislocation plays an important role and revealed interesting results with respect to our understanding of the intrinsic dislocation structure in bcc metals. These results support the kink chain model for dislocation unambiguously. The experiments on the prestrained samples also exhibited experimental results which are qualitatively but not quantitatively in agreement with the theoretical predictions of Seeger and Sectak. The Ni single crystals were prestrained between 10 and 23 percent in stage II, and the microstrain damping loops have been studied as a function of stress amplitude, temperature and magnetic field. The predominant hysteretic contribution to the observed decrement was analyzed according to the model of Roberts (Al. 14, Al. 15), and good agreement between theory and experiment was found

Surface-Anchored Poly(4-vinylpyridine)–Single-Walled Carbon Nanotube–Metal Composites for Gas Detection

KAUST Repository

Yoon, Bora

2016-08-05

A platform for chemiresistive gas detectors based upon single-walled carbon nanotube (SWCNT) dispersions stabilized by poly(4-vinylpyridine) (P4VP) covalently immobilized onto a glass substrate was developed. To fabricate these devices, a glass substrate with gold electrodes is treated with 3-bromopropyltrichlorosilane. The resulting alkyl bromide coating presents groups that can react with the P4VP to covalently bond (anchor) the polymer–SWCNT composite to the substrate. Residual pyridyl groups in P4VP not consumed in this quaternization reaction are available to coordinate metal nanoparticles or ions chosen to confer selectivity and sensitivity to target gas analytes. Generation of P4VP coordinated to silver nanoparticles produces an enhanced response to ammonia gas. The incorporation of soft Lewis acidic Pd2+ cations by binding PdCl2 to P4VP yields a selective and highly sensitive device that changes resistance upon exposure to vapors of thioethers. The latter materials have utility for odorized fuel leak detection, microbial activity, and breath diagnostics. A third demonstration makes use of permanganate incorporation to produce devices with large responses to vapors of volatile organic compounds that are susceptible to oxidation.

Area G perimeter surface-soil and single-stage water sampling: Environmental surveillance for fiscal year 1993

International Nuclear Information System (INIS)

Conrad, R.; Childs, M.; Rivera-Dirks, C.; Coriz, F.

1995-07-01

Area G, in Technical Area 54, has been the principle facility at Los Alamos National Laboratory for the storage and disposal of low-level and transuranic (TRU) radioactive wastes since 1957. The current environmental investigation consisted of ESH-19 personnel who collected soil and single-stage water samples around the perimeter of Area G to characterize possible contaminant movement through surface-water runoff. These samples were analyzed for tritium, total uranium, isotopic plutonium, americium-241 (soil only), and cesium 137. The metals, mercury, lead, and barium, were analyzed using x-ray fluorescence

A dual-stage sodium thermal electrochemical converter (Na-TEC)

Science.gov (United States)

Limia, Alexander; Ha, Jong Min; Kottke, Peter; Gunawan, Andrey; Fedorov, Andrei G.; Lee, Seung Woo; Yee, Shannon K.

2017-12-01

The sodium thermal electrochemical converter (Na-TEC) is a heat engine that generates electricity through the isothermal expansion of sodium ions. The Na-TEC is a closed system that can theoretically achieve conversion efficiencies above 45% when operating between thermal reservoirs at 1150 K and 550 K. However, thermal designs have confined previous single-stage devices to thermal efficiencies below 20%. To mitigate some of these limitations, we consider dividing the isothermal expansion into two stages; one at the evaporator temperature (1150 K) and another at an intermediate temperature (650 K-1050 K). This dual-stage Na-TEC takes advantage of regeneration and reheating, and could be amenable to better thermal management. Herein, we demonstrate how the dual-stage device can improve the efficiency by up to 8% points over the best performing single-stage device. We also establish an application regime map for the single- and dual-stage Na-TEC in terms of the power density and the total thermal parasitic loss. Generally, a single-stage Na-TEC should be used for applications requiring high power densities, whereas a dual-stage Na-TEC should be used for applications requiring high efficiency.

Unconditional and Conditional QTL Mapping for Tiller Numbers at Various Stages with Single Segment Substitution Lines in Rice (Oryza sativa L.)

Institute of Scientific and Technical Information of China (English)

ZHAO Fang-ming; LIU Gui-fu; ZHU Hai-tao; DING Xiao-hua; ZENG Rui-zhen; ZHANG Ze-min; LI Wen-tao; ZHANG Gui-quan

2008-01-01

Tiller is one of the most important agronomic traits which influences quantity and quality of effective panicles and finally influences yield in rice.It is important to understand "static" and "dynamic" information of the QTLs for tillers in rice.This work was the first time to simultaneously map unconditional and conditional QTLs for tiller numbers at various stages by using single segment substitution lines in rice.Fourteen QTLs for tiller number,distributing on the corresponding substitution segments of chromosomes 1,2,3,4,6,7 and 8 were detected.Both the number and the effect of the QTLs for tiller number were various at different stages,from 6 to 9 in the number and from 1.49 to 3.49 in the effect,respectively. Tiller number QTLs expressed in a time order,mainly detected at three stages of 0-7d,14-21d and 35-42d after transplanting with 6 positive,9 random and 6 negative expressing QTLs,respectively.Each of the QTLs expressed one time at least during the whole duration of rice.The tiller number at a specific stage was determined by sum of QTL effects estimated by the unconditional method,while the increasing or decreasing number in a given time interval was controlled by the total of QTL effects estimated by the conditional method.These results demonstrated that it is highly effective and accurate for mapping of the QTLs by using single segment substitution lines and the conditional analysis methodology.

Natural Gas Liberalisation and Deregulation - The German Gas Industry's View

International Nuclear Information System (INIS)

Czernie, W.

2001-01-01

In Europe, the process of creating a single energy market is under way. The 1998 Gas Directive established an important date for the European gas industry. On 10 August 1998, ''Directive 98/30/EC of the European Parliament and of the Council of 22 June 1998 concerning common rules for the internal market in natural gas'' came into force. It had to be transposed into national law by the EU member states within two years, i.e. by 10 August 2000. The Directive is a cornerstone in establishing a competitive gas market in the European Union. It is the outcome of several years of negotiations and can be regarded as a compromise between the various interests. On the whole, it leaves EU member states with sufficient scope for adequately taking account of national characteristics in keeping with the principle of subsidiarity. The process of transposing the Gas Directive into the national law of individual EU member states is being closely followed by the European Commission. While acknowledging all the progress made in the single market process, the Commission still detects shortcomings in the implementation of the Gas Directive on the road to an actual single market. This is seen as a justification for new initiatives and intervention, even though the new political framework for the gas industry has not yet been tested in practice and been able to prove itself on a broad scale for any length of time. In the debate on liberalisation, tried-and-tested instruments of secure and market-oriented gas supply on the European continent long-term supply contracts with take-or-pay clauses and competitive oil-indexed gas prices have also come under scrutiny. However, even under the conditions of liberalisation, security of supply has to be achieved mainly by a balanced mix of supply sources and by long-term supply contracts, including competitive pricing as ensured by so-called oil indexing. In the further liberalisation of west European gas industries, it will be essential to ensure

Satisfactory knee function after single-stage posterolateral corner reconstruction in the multi-ligament injured/dislocated knee using the anatomic single-graft technique.

Science.gov (United States)

Sanders, Thomas L; Johnson, Nick R; Pareek, Ayoosh; Krych, Aaron J; Marx, Robert G; Stuart, Michael J; Levy, Bruce A

2018-04-01

Increasing importance has been placed on the posterolateral corner (PLC) in maintaining varus and rotational stability of the knee. The goal of this study was to evaluate knee function and clinical stability following a single-graft PLC reconstruction technique and identify factors associated with poor knee function. This study identified patients with a multi-ligament knee injury between 2006 and 2013. Patients who received a single-graft fibular collateral ligament and PLC reconstruction with a single-stage surgery during the study period and had a minimum follow-up of 2 years after surgery were included. Functional outcomes were assessed using Lysholm and IKDC scores. Varus and rotational knee laxity and range of motion were assessed using physical examination. The final study cohort included 61 patients who underwent PLC reconstruction using a single-graft technique. The mean IKDC score was 74.1 (± 22.3) and the mean Lysholm score was 80.3 (± 21.8) at mean follow-up of 3.8 years (range 2-9 years). Mean range of motion at final follow-up measured from 0° to 126° [range flexion: 95-145, range extension: 0-5]. Fifty-eight patients (95%) had grade 0 varus laxity in full knee extension, and 54 patients (88.5%) had grade 0 varus laxity at 30° of knee flexion. Female gender was associated with a lower postoperative IKDC score (p = 0.04). Surgical treatment of the PLC using a single-graft technique can result in satisfactory knee function and stable physical examination findings at minimum 2 years after surgery. Female gender was predictive of poor knee function after PLC reconstruction. Surgical treatment of PLC injuries should be individualized based on the timing of surgery, specific injured knee structures, and physical examination findings. This study helps validate the use of a single-graft technique for PLC reconstruction and can be used to help counsel patients about expected knee function after surgical treatment of PLC injuries. Level of evidence

Cerebral staging of lung cancer: is one single contrast-enhanced T1-weighted three-dimensional gradient-echo sequence sufficient?

Energy Technology Data Exchange (ETDEWEB)

Ohana, Mickael; Jeung, Mi-Young; Roy, Catherine [Nouvel Hopital Civil-Hopitaux Universitaires de Strasbourg, Service de Radiologie B/Radiology Department, Strasbourg (France); Bazille, Gauthier [Clinique Saint Anne-Groupe Radiologique MIM, Strasbourg (France)

2014-08-15

Gadolinium-enhanced magnetic resonance imaging (MRI) is the gold standard for cerebral staging in thoracic oncology. We hypothesize that a minimalist examination, consisting of a single contrast-enhanced T1-weighted three-dimensional gradient-echo sequence (CE 3D-GRE), would be sufficient for the cerebral staging of nonsymptomatic lung cancer patients. Seventy nonsymptomatic patients (50 % men; 62 years ± 10.2) referred for cerebral staging of a lung cancer were retrospectively included. All underwent a standard 3 T MRI examination with T1, FLAIR, T2* GRE, diffusion, and CE 3D-GRE sequences, for a total examination time of 20 min. The sole CE 3D-GRE (acquisition time: 6 min) was extracted and blindly interpreted by two radiologists in search of brain metastases. Hemorrhagic features of potential lesions and relevant incidental findings were also noted. Discrepant cases were reviewed by a third reader. The full MRI examination and follow-up studies were used as a reference to calculate sensitivity and specificity of the sole CE 3D-GRE. Thirty-eight point six percent (27 out of 70) of the patients had brain metastases. Performances and reader's agreement with the sole CE 3D-GRE sequence were excellent for the diagnosis of brain metastases (sensitivity = 96.3 %, specificity = 100 %, κ = 0.91) and incidental findings (sensitivity = 85.7 %, specificity = 100 %, κ = 0.62) but insufficient for the identification of hemorrhages within the metastases (sensitivity = 33.3 %, specificity = 85.7 %, κ = 0.47). In the specific case of lung cancer, cerebral staging in nonsymptomatic patients can be efficiently achieved with a minimalistic protocol consisting of a single CE 3D-GRE sequence, completed if positive with a T2* sequence for hemorrhagic assessment, thus halving appointment delays. (orig.)

Quantification of regional early stage gas exchange changes using hyperpolarized "1"2"9Xe MRI in a rat model of radiation-induced lung injury

International Nuclear Information System (INIS)

Doganay, Ozkan; Stirrat, Elaine; McKenzie, Charles; Schulte, Rolf F.; Santyr, Giles E.

2016-01-01

Purpose: To assess the feasibility of hyperpolarized (HP) "1"2"9Xe MRI for detection of early stage radiation-induced lung injury (RILI) in a rat model involving unilateral irradiation by assessing differences in gas exchange dynamics between irradiated and unirradiated lungs. Methods: The dynamics of gas exchange between alveolar air space and pulmonary tissue (PT), PT and red blood cells (RBCs) was measured using single-shot spiral iterative decomposition of water and fat with echo asymmetry and least-squares estimation images of the right and left lungs of two age-matched cohorts of Sprague Dawley rats. The first cohort (n = 5) received 18 Gy irradiation to the right lung using a "6"0Co source and the second cohort (n = 5) was not irradiated and served as the healthy control. Both groups were imaged two weeks following irradiation when radiation pneumonitis (RP) was expected to be present. The gas exchange data were fit to a theoretical gas exchange model to extract measurements of pulmonary tissue thickness (L_P_T) and relative blood volume (V_R_B_C) from each of the right and left lungs of both cohorts. Following imaging, lung specimens were retrieved and percent tissue area (PTA) was assessed histologically to confirm RP and correlate with MRI measurements. Results: Statistically significant differences in L_P_T and V_R_B_C were observed between the irradiated and non-irradiated cohorts. In particular, L_P_T of the right and left lungs was increased approximately 8.2% and 5.0% respectively in the irradiated cohort. Additionally, V_R_B_C of the right and left lungs was decreased approximately 36.1% and 11.7% respectively for the irradiated cohort compared to the non-irradiated cohort. PTA measurements in both right and left lungs were increased in the irradiated group compared to the non-irradiated cohort for both the left (P < 0.05) and right lungs (P < 0.01) confirming the presence of RP. PTA measurements also correlated with the MRI measurements for both

A strategic model of European gas supply

International Nuclear Information System (INIS)

Holz, Franziska; Hirschhausen, Christian von; Kemfert, Claudia

2005-01-01

Structural changes in the European natural gas market such as liberalization, increasing demand, and growing import dependency have triggered new attempts to model these markets accurately. This paper proposes a model of the European natural gas supply including the possibility of strategic behavior of the agents along the value-added chain. We structure it as a two-stage-game of successive natural gas exports to Europe (first stage) and wholesale trade within Europe (second stage). In the case of non-cooperative Cournot competition at both stages, which is the most realistic scenario, this yields a market outcome with double marginalization, that is suppliers at both stages generate a mark-up, at the expense of the final customers. Our results suggest that the main suppliers of natural gas to Europe remain dominant (Norway, the Netherlands), although some lose market shares (Algeria, UK, and especially Russia). Traditional exports will be complemented in the future by overseas supplies of LNG from the Middle East, Nigeria, Trinidad and Tobago which are becoming competitive. The model also enables us to identify transport infrastructure bottlenecks; we find that transport capacity on the upstream market is sufficient but the capacity constraint is binding for many intra-EU trade relations. (Author)

Two-Stage Centrifugal Fan

Science.gov (United States)

Converse, David

2011-01-01

Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

Emission characteristics of multiple stage diesel combustion. Effect of exhaust gas recirculation; Nidan nensho diesel kikan no haishutsubutsu tokusei. EGR no eikyo

Energy Technology Data Exchange (ETDEWEB)

Hashizume, T.; Miyamoto, T.; Akagawa, H.; Tsujimura, K. [New A.C.E. Institute Co. Ltd., Tokyo (Japan)

1998-05-01

For an aim to reduce NOx emission from diesel engines, it has become possible to realize it with smoke emission maintained at low levels by taking the following steps: initial combustion is carried out as lean pre-mixed combustion by adopting early fuel injection; the fuel is injected again after completion of this combustion; and EGR is combined with two-stage combustion which performs diffusion combustion under high temperature atmosphere. When a large quantity of EGR is used, cylinder temperature drops to have ignition timing delayed in the first stage, serving for improving fuel consumption. The problem of increase in smoke generation is solved by optimizing the injection timing at the second stage to suppress smoke generation increase, resulting in realization of lower NOx emission. By completing the second-stage fuel injection before ignition of the first-stage injection, it was possible to realize further lower NOx emission. Smoke increase due to higher EGR ratio was suppressed by pre-mixing both fuels injected in the first and second stages, although this is a high load operation. In addition, oxygen concentration and cylinder temperature were reduced, the gas pre-mixture was homogenized, and combustion velocity was suppressed by delaying the angle of ignition timing. This made low smoke combustion at {lambda} = 1 possible even in compressed ignition combustion. 8 refs., 12 figs., 1 tab.

Gas at work. Vision on decentralized gas appliances in the built environment

International Nuclear Information System (INIS)

Van Gastel, M.; Hooijschuur, J.; De Jong, A.; De Visser, I.; Overdiep, H.; Bakker, E.J.; Van Wolferen, H.

2008-04-01

Various platforms operate within the SenterNovem programme Creative Energy. This report is the first version of the vision document of the working group Decentralized gas appliances of the Platform New Gas, in which the following aspects of the various promising innovative gas appliances are indicated: the development stage, the intended energy saving, the CO2 reduction, the bottlenecks for large scale market introduction and the solutions for these bottlenecks. [mk] [nl

Single channel analog pulse processor Asic for gas proportional counters and SI detector

International Nuclear Information System (INIS)

Chandratre, V.B.; Sarkar, Soumen; Kataria, S.K.; Viyogi, Y.P.

2005-01-01

The paper presents the design and development of a single channel pulse processor in short Singleplex ASIC targeted for gas proportional counters/Si detectors. The design is optimized for the dynamic range of +500 fC to -500 fC with provision for externally adjusted pole-zero cancellation. A dedicated filter based on the de-convolution principle is used for the cancellation of the long hyperbolic signal tail produced by the slow drift of ions, typical in gas proportional with the filter time constants derived from the actual detector input signal shape. The pole-zero adjustment can be done by external dc voltage to achieve perfect base-line recovery to 1% after 5 μs. The simulated 0 pf noise is 500 e - rms for the peaking time of 1.2 μs with noise slope of 7e - -. The gain is 3.4 mv/fC over the entire linear dynamic range with power dissipation of 13 mW. This design is a modified version of Indiplex chip with features dynamic range equal gain on both polarities with nearly same noise and serves as diagnostic chip for Indiplex. The chip can be used for radiation monitoring instruments. (author)

Staged fluidized-bed combustion and filter system

International Nuclear Information System (INIS)

Mei, J.S.; Halow, J.S.

1994-01-01

A staged fluidized-bed combustion and filter system are described for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste. 10 figures

Fundamentals of gas particle flow

CERN Document Server

Rudinger, G

1980-01-01

Fundamentals of Gas-Particle Flow is an edited, updated, and expanded version of a number of lectures presented on the "Gas-Solid Suspensions” course organized by the von Karman Institute for Fluid Dynamics. Materials presented in this book are mostly analytical in nature, but some experimental techniques are included. The book focuses on relaxation processes, including the viscous drag of single particles, drag in gas-particles flow, gas-particle heat transfer, equilibrium, and frozen flow. It also discusses the dynamics of single particles, such as particles in an arbitrary flow, in a r

A safety equipment list for rotary mode core sampling systems operation in single shell flammable gas tanks

International Nuclear Information System (INIS)

SMALLEY, J.L.

1999-01-01

This document identifies all interim safety equipment to be used for rotary mode core sampling of single-shell flammable gas tanks utilizing Rotary Mode Core Sampling systems (RMCS). This document provides the safety equipment for RMCS trucks HO-68K-4600, HO-68K-4647, trucks three and four respectively, and associated equipment. It is not intended to replace or supersede WHC-SD-WM-SEL-023, (Kelly 1991), or WHC-SD-WM-SEL-032, (Corbett 1994), which classifies 80-68K-4344 and HO-68K-4345 respectively. The term ''safety equipment'' refers to safety class (SC) and safety significant (SS) equipment, where equipment refers to structures, systems and components (SSC's). The identification of safety equipment in this document is based on the credited design safety features and analysis contained in the Authorization Basis (AB) for rotary mode core sampling operations in single-shell flammable gas tanks. This is an interim safety classification since the AB is interim. This document will be updated to reflect the final RMCS equipment safety classification designations upon completion of a final AB which will be implemented with the release of the Final Safety Analysis Report (FSAR)

Evaluation of natural gas supply options for south east and central Europe. Part 1: Indicator definitions and single indicator analysis

International Nuclear Information System (INIS)

Afgan, Naim H.; Carvalho, Maria G.; Pilavachi, Petros A.; Martins, Nelson

2007-01-01

The need for diversification of energy sources is an immanent goal in long term energy strategy. In particular, this is of great importance for the natural gas supply. In this respect, evaluation and assessment of potential natural gas resources and their relation to consumers is of great importance. The natural gas supply in Europe is one of the main issues of European energy strategy to be followed in the future. In particular, the natural gas supply in the southeast countries is important. This paper provides a framework for understanding how much natural gas is available for use in south east and central Europe as well as the links to the recent supply of natural gas and its transport. The analysis is focused on evaluation of the potential routes for natural gas supply to the south east and central European countries. The potential options included in this analysis are the Yamal Route; Nabucco Route; West Balkan Route; LNG NEUM Route and Gas by Wire Route. In this analysis, attention is focused on the following indicators for assessment of potential options: environmental indicator; NG cost indicator; NG transport and royalty indicator; investment indicator; and NG demand indicator. The first part of this paper is devoted to the definition of the indicators and to single indicator analysis. (author)

Performance analysis of the single-stage absorption heat transformer using a new working pair composed of ionic liquid and water

International Nuclear Information System (INIS)

Zhang Xiaodong; Hu Dapeng

2012-01-01

The performance simulation of a single-stage absorption heat transformer using a new working pair composed of ionic liquids, 1-ethyl-3-methylimidazolium dimethylphosphate, and water (H 2 O + [EMIM][DMP]), was performed based on the thermodynamic properties of the new working pair and on the mass and energy balance for each component of the system. In order to evaluate the new working pair, the simulation results were compared with those of aqueous solution of lithium bromide (H 2 O + LiBr), Trifluoroethanol (TFE) + tetraethylenglycol dimethylether (E181). The results indicate that when generation, evaporation, condensing and absorption temperatures are 90 °C, 90 °C, 35 °C and 130 °C, the coefficients of performance of the single-stage absorption heat transformer using H 2 O + LiBr, H 2 O + [EMIM][DMP] and TFE + E181 as working pairs will reach 0.494, 0.481 and 0.458 respectively. And the corresponding exergy efficiency will reach 0.64, 0.62 and 0.59, respectively. Meanwhile the available heat outputs for per unit mass of refrigerant are 2466 kJ/kg, 2344 kJ/kg and 311 kJ/kg, respectively. The above excellent cycle performance together with the advantages of negligible vapor pressure, no crystallization and more weak corrosion tendency to iron-steel materials may make the new working pair better suited for the industrial absorption heat transformer. - Highlights: ► The cycle performance of the single-stage absorption heat transformer was simulated. ► Water and 1-ethyl-3-methylimidazolium dimethylphosphate was used as new working pair. ► Water and 1-ethyl-3-methylimidazolium dimethylphosphate are entirely miscible. ► The COP and exergy efficiency for this new working pairs were 0.481 and 0.62. ► The new working pairs has potential application to absorption heat transformer.

Multi-staging for extraction of cesium from nitric acid by a single liquid-liquid countercurrent centrifugal extractor with Taylor vortices

International Nuclear Information System (INIS)

Nakase, Masahiko; Kinuhata, Hiroshi; Takeshita, Kenji

2013-01-01

Fission products that emit considerable decay heat and radioactivity, such as 137 Cs, have a large impact on waste management. Small and high-performance extractor is desirable for separating such nuclei. In this study, we implemented the continuous extraction of Cs from nitric acid in a single liquid-liquid countercurrent centrifugal extractor with Taylor Vortices by calix arene-bis(t-octylbenzo-crown-6)(BOBCalixC6) as an extractant with trioctylamine(TOA) as a suppressant and with 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) as a phase modifier. Because of slow extraction kinetics of this process, extraction with multiple theoretical stages by just replacing conventional extractors into the single centrifugal extractor is difficult. Hence, we improved the dispersion of organic phase by an inner rotor made of lipophilic epoxy resin and elevating the solution temperature to lower the viscosity. Higher temperature was not appropriate from the aspect of chemical equilibrium in this process, but extraction with multiple theoretical stages was found to be possible. (author)

Single-Staged Compared With Multi-Staged PCI in Multivessel NSTEMI Patients: The SMILE Trial.

Science.gov (United States)

Sardella, Gennaro; Lucisano, Luigi; Garbo, Roberto; Pennacchi, Mauro; Cavallo, Erika; Stio, Rocco Edoardo; Calcagno, Simone; Ugo, Fabrizio; Boccuzzi, Giacomo; Fedele, Francesco; Mancone, Massimo

2016-01-26

A lack of clarity exists about the role of complete coronary revascularization in patients presenting with non-ST-segment elevation myocardial infarction. The aim of our study was to compare long-term outcomes in terms of major adverse cardiovascular and cerebrovascular events of 2 different complete coronary revascularization strategies in patients with non-ST-segment elevation myocardial infarction and multivessel coronary artery disease: 1-stage percutaneous coronary intervention (1S-PCI) during the index procedure versus multistage percutaneous coronary intervention (MS-PCI) complete coronary revascularization during the index hospitalization. In the SMILE (Impact of Different Treatment in Multivessel Non ST Elevation Myocardial Infarction Patients: One Stage Versus Multistaged Percutaneous Coronary Intervention) trial, 584 patients were randomly assigned in a 1:1 manner to 1S-PCI or MS-PCI. The primary study endpoint was the incidence of major adverse cardiovascular and cerebrovascular events, which were defined as cardiac death, death, reinfarction, rehospitalization for unstable angina, repeat coronary revascularization (target vessel revascularization), and stroke at 1 year. The occurrence of the primary endpoint was significantly lower in the 1-stage group (1S-PCI: n = 36 [13.63%] vs. MS-PCI: n = 61 [23.19%]; hazard ratio [HR]: 0.549 [95% confidence interval (CI): 0.363 to 0.828]; p = 0.004). The 1-year rate of target vessel revascularization was significantly higher in the MS-PCI group (1S-PCI: n = 22 [8.33%] vs. MS-PCI: n = 40 [15.20%]; HR: 0.522 [95% CI: 0.310 to 0.878]; p = 0.01; p log-rank = 0.013). When the analyses were limited to cardiac death (1S-PCI: n = 9 [3.41%] vs. MS-PCI: n = 14 [5.32%]; HR: 0.624 [95% CI: 0.270 to 1.441]; p = 0.27) and myocardial infarction (1S-PCI: n = 7 [2.65%] vs. MS-PCI: n = 10 [3.80%]; HR: 0.678 [95% CI: 0.156 to 2.657]; p = 0.46), no significant differences were observed between groups. In multivessel

Gas swelling behaviour at different stages in Li4Ti5O12/LiNi1/3Co1/3Mn1/3O2 pouch cells

Science.gov (United States)

Liu, Wei; Liu, Haohan; Wang, Qian; Zhang, Jian; Xia, Baojia; Min, Guoquan

2017-11-01

Gas swelling behaviour is a major drawback of batteries that are based on Li4Ti5O12 anode materials and hinders their application. In this article, the morphology and electronic structure changes of Li4Ti5O12 electrodes at ageing and cycling stages are investigated using scanning electron microscopy, X-ray absorption near-edge structure and X-ray photoelectron spectroscopy. A simple method that uses an air bag to collect the generated gases was conducted and the gases were then characterised by gas chromatography/mass spectrometry. The results indicate that the charge transformation of Ti ions would aggravate the gas swelling behaviour. The solid electrolyte interphase (SEI) films form on the surface of the Li4Ti5O12 particles and become thicker with increasing charge state. The gas components change significantly during the ageing and cycling, indicating the complexity of the gas swelling mechanism.

Capacitor blocks for linear transformer driver stages.

Science.gov (United States)

Kovalchuk, B M; Kharlov, A V; Kumpyak, E V; Smorudov, G V; Zherlitsyn, A A

2014-01-01

In the Linear Transformer Driver (LTD) technology, the low inductance energy storage components and switches are directly incorporated into the individual cavities (named stages) to generate a fast output voltage pulse, which is added along a vacuum coaxial line like in an inductive voltage adder. LTD stages with air insulation were recently developed, where air is used both as insulation in a primary side of the stages and as working gas in the LTD spark gap switches. A custom designed unit, referred to as a capacitor block, was developed for use as a main structural element of the transformer stages. The capacitor block incorporates two capacitors GA 35426 (40 nF, 100 kV) and multichannel multigap gas switch. Several modifications of the capacitor blocks were developed and tested on the life time and self breakdown probability. Blocks were tested both as separate units and in an assembly of capacitive module, consisting of five capacitor blocks. This paper presents detailed design of capacitor blocks, description of operation regimes, numerical simulation of electric field in the switches, and test results.

A study of a high temperature nuclear power plant incorporating a non-integrated indirect cycle gas turbine

International Nuclear Information System (INIS)

Sarlos, G.; Helbling, W.; Zollinger, E.; Gregory, N.; Luchsinger, H.

1982-04-01

In connection with the HHT-project, the Swiss Federal Institute for Reactor Research has performed a study of a 1640-MWth HTR-plant incorporating a non-integrated indirect cycle gas turbine with two-stage intercooling, as a possibility of simplifying and reducing the cost of the HHT-demonstration plant. In this paper, the plant design is described and compared with the HHT-demonstration plant (a CCGT integrated plant with single stage intercooling). Also included is an evaluation of the various advantages and disadvantages of this design together with the presentation of some of the sensitivity results. (Auth.)

Simulated dynamic response of a multi-stage compressor with variable molecular weight flow medium

Science.gov (United States)

Babcock, Dale A.

1995-01-01

A mathematical model of a multi-stage compressor with variable molecular weight flow medium is derived. The modeled system consists of a five stage, six cylinder, double acting, piston type compressor. Each stage is followed by a water cooled heat exchanger which serves to transfer the heat of compression from the gas. A high molecular weight gas (CFC-12) mixed with air in varying proportions is introduced to the suction of the compressor. Condensation of the heavy gas may occur in the upper stage heat exchangers. The state equations for the system are integrated using the Advanced Continuous Simulation Language (ACSL) for determining the system's dynamic and steady state characteristics under varying operating conditions.

Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

DEFF Research Database (Denmark)

Domingo Felez, Carlos; Mutlu, A. Gizem; Jensen, Marlene Mark

2014-01-01

Autotrophic nitrogen removal is regarded as a resource efficient process to manage nitrogen-rich residual streams. However, nitrous oxide emissions of these processes are poorly documented and strategies to mitigate emissions unknown. In this study, two sequencing batch reactors performing single...... was noted when the duration of aeration was increased while decreasing air flow rate (10.9 +/- 3.2% Delta N2O/Delta TN). The extant ammonium oxidation activity (mgNH(4)(+)-N/gVSS.min) positively correlated with the specific N2O production rate (mgN(2)O-N/gVSS.min) of the systems. Operating under conditions......-stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75g-N/L.d) and high nitrogen removal efficiencies (83 +/- 5 and 88 +/- 2%) obtained. Dynamics of liquid phase nitrous (N2O...

Gas production strategy of underground coal gasification based on multiple gas sources.

Science.gov (United States)

Tianhong, Duan; Zuotang, Wang; Limin, Zhou; Dongdong, Li

2014-01-01

To lower stability requirement of gas production in UCG (underground coal gasification), create better space and opportunities of development for UCG, an emerging sunrise industry, in its initial stage, and reduce the emission of blast furnace gas, converter gas, and coke oven gas, this paper, for the first time, puts forward a new mode of utilization of multiple gas sources mainly including ground gasifier gas, UCG gas, blast furnace gas, converter gas, and coke oven gas and the new mode was demonstrated by field tests. According to the field tests, the existing power generation technology can fully adapt to situation of high hydrogen, low calorific value, and gas output fluctuation in the gas production in UCG in multiple-gas-sources power generation; there are large fluctuations and air can serve as a gasifying agent; the gas production of UCG in the mode of both power and methanol based on multiple gas sources has a strict requirement for stability. It was demonstrated by the field tests that the fluctuations in gas production in UCG can be well monitored through a quality control chart method.

Life cycle water consumption for shale gas and conventional natural gas.

Science.gov (United States)

Clark, Corrie E; Horner, Robert M; Harto, Christopher B

2013-10-15

Shale gas production represents a large potential source of natural gas for the nation. The scale and rapid growth in shale gas development underscore the need to better understand its environmental implications, including water consumption. This study estimates the water consumed over the life cycle of conventional and shale gas production, accounting for the different stages of production and for flowback water reuse (in the case of shale gas). This study finds that shale gas consumes more water over its life cycle (13-37 L/GJ) than conventional natural gas consumes (9.3-9.6 L/GJ). However, when used as a transportation fuel, shale gas consumes significantly less water than other transportation fuels. When used for electricity generation, the combustion of shale gas adds incrementally to the overall water consumption compared to conventional natural gas. The impact of fuel production, however, is small relative to that of power plant operations. The type of power plant where the natural gas is utilized is far more important than the source of the natural gas.

Single-staged resections and 3D reconstructions of the nasion, glabella, medial orbital wall, and frontal sinus and bone: Long-term outcome and review of the literature.

Science.gov (United States)

Ciporen, Jeremy; Lucke-Wold, Brandon P; Mendez, Gustavo; Chen, Anton; Banerjee, Amit; Akins, Paul T; Balough, Ben J

2016-01-01

Aesthetic facial appearance following neurosurgical ablation of frontal fossa tumors is a primary concern for patients and neurosurgeons alike. Craniofacial reconstruction procedures have drastically evolved since the development of three-dimensional computed tomography imaging and computer-assisted programming. Traditionally, two-stage approaches for resection and reconstruction were used; however, these two-stage approaches have many complications including cerebrospinal fluid leaks, necrosis, and pneumocephalus. We present two successful cases of single-stage osteoma resection and craniofacial reconstruction in a 26-year-old female and 65-year-old male. The biopolymer implants were preselected and contoured based on imaging prior to surgery. The ideal selection of appropriate flaps for reconstruction was imperative. The flaps were well vascularized and included a pedicle for easy translocation. Using a titanium mesh biopolymer implant for reconstruction in conjunction with a forehead flap proved advantageous, and the benefits of single-stage approaches were apparent. The patients recovered quickly after the surgery with complete resection of the osteoma and good aesthetic appearance. The flap adhered to the biopolymer implant, and the cosmetic appearance years after surgery remained decent. The gap between the bone and implant was less than 2 mm. The patients are highly satisfied with the symmetrical appearance of the reconstruction. Advances in technology are allowing neurosurgeons unprecedented opportunities to design complex yet feasible single-stage craniofacial reconstructions that improve a patient's quality of life by enhancing facial contours, aesthetics, and symmetry.

Detection of Brucella melitensis and Brucella abortus strains using a single-stage PCR method

Directory of Open Access Journals (Sweden)

Alamian, S.

2015-04-01

Full Text Available Brucella melitensis and Brucella abortus are of the most important causes of brucellosis, an infectious disease which is transmitted either directly or indirectly including consuming unpasteurized dairy products. Both strains are considered endemic in Iran. Common diagnostic methods such as bacteriologic cultures are difficult and time consuming regarding the bacteria. The aim of this study was to suggest a single-stage PCR method using a pair of primers to detect both B. melitensis and B. abortus. The primers were named UF1 and UR1 and the results showed that the final size of PCR products were 84 bp and 99 bp for B. melitensis and B. abortus, respectively. Therefore the method could be useful for rapid detection of B. melitensis and B. abortus simultaneously.

Lithium recovery from shale gas produced water using solvent extraction

International Nuclear Information System (INIS)

Jang, Eunyoung; Jang, Yunjai; Chung, Eunhyea

2017-01-01

Shale gas produced water is hypersaline wastewater generated after hydraulic fracturing. Since the produced water is a mixture of shale formation water and fracturing fluid, it contains various organic and inorganic components, including lithium, a useful resource for such industries as automobile and electronics. The produced water in the Marcellus shale area contains about 95 mg/L lithium on average. This study suggests a two-stage solvent extraction technique for lithium recovery from shale gas produced water, and determines the extraction mechanism of ions in each stage. All experiments were conducted using synthetic shale gas produced water. In the first-stage, which was designed for the removal of divalent cations, more than 94.4% of Ca"2"+, Mg"2"+, Sr"2"+, and Ba"2"+ ions were removed by using 1.0 M di-(2-ethylhexyl) phosphoric acid (D2EHPA) as an extractant. In the second-stage, for lithium recovery, we could obtain a lithium extraction efficiency of 41.2% by using 1.5 M D2EHPA and 0.3 M tributyl phosphate (TBP). Lithium loss in the first-stage was 25.1%, and therefore, the total amount of lithium recovered at the end of the two-step extraction procedure was 30.8%. Through this study, lithium, one of the useful mineral resources, could be selectively recovered from the shale gas produced water and it would also reduce the wastewater treatment cost during the development of shale gas. - Highlights: • Lithium was extracted from shale gas produced water using an organic solvent. • Two-stage solvent extraction technique was applied. • Divalent cations were removed in the first stage by D2EHPA. • Lithium was selectively recovered in the second stage by using TBP with D2EHPA.

Numerical simulation by CFD of the behavior of the Inter stage 1 flow in stable state of a gas turbine Frame 7; Simulacion numerica por CFD del comportamiento del flujo en la inter etapa 1 en estado estable de una turbina de gas frame 7

Energy Technology Data Exchange (ETDEWEB)

Hernandez R, Alejandro; Lopez H, Juan Arturo R; Mazur Czerwiec, Zdizslaw; Cordero G, Jesus [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2006-07-01

This technical article presents an analysis including the three-dimensional modeling of the flow channel in the nozzle and the movable blade in order to discover the velocity distribution, temperatures and pressures of the main hot gas flow produced in the inter-stage 1. The aim is to establish key evaluation criteria leading to an opportune repair and therefore smaller operation expenses. Thus, the application of a commercial software of CFD is described to model the channel of the first stage in the gas turbine Frame 7, the geometric architecture is shown in the web of the gas turbine, as well as the border conditions used in the results assessment. [Spanish] Este articulo tecnico presenta un analisis que incluye la modelacion tridimensional del canal de flujo en la tobera y el alabe movil para conocer las distribuciones de las velocidades, temperaturas y presiones del flujo principal de gases calientes que se desarrollan en la inter-etapa 1. El fin es establecer criterios clave de evaluacion que conduzcan a una oportuna reparacion y por ende menores gastos de operacion. Asi, se describe la aplicacion de un software comercial de CFD para modelar el canal de flujo de la primera etapa de una turbina de gas Frame 7, se muestra la arquitectura geometrica y el mallado de la turbina de gas, asi como las condiciones de frontera usadas y la validacion de resultados.

SU-E-T-480: Radiobiological Dose Comparison of Single Fraction SRS, Multi-Fraction SRT and Multi-Stage SRS of Large Target Volumes Using the Linear-Quadratic Formula

International Nuclear Information System (INIS)

Ding, C; Hrycushko, B; Jiang, S; Meyer, J; Timmerman, R

2014-01-01

Purpose: To compare the radiobiological effect on large tumors and surrounding normal tissues from single fraction SRS, multi-fractionated SRT, and multi-staged SRS treatment. Methods: An anthropomorphic head phantom with a centrally located large volume target (18.2 cm 3 ) was scanned using a 16 slice large bore CT simulator. Scans were imported to the Multiplan treatment planning system where a total prescription dose of 20Gy was used for a single, three staged and three fractionated treatment. Cyber Knife treatment plans were inversely optimized for the target volume to achieve at least 95% coverage of the prescription dose. For the multistage plan, the target was segmented into three subtargets having similar volume and shape. Staged plans for individual subtargets were generated based on a planning technique where the beam MUs of the original plan on the total target volume are changed by weighting the MUs based on projected beam lengths within each subtarget. Dose matrices for each plan were export in DICOM format and used to calculate equivalent dose distributions in 2Gy fractions using an alpha beta ratio of 10 for the target and 3 for normal tissue. Results: Singe fraction SRS, multi-stage plan and multi-fractionated SRT plans had an average 2Gy dose equivalent to the target of 62.89Gy, 37.91Gy and 33.68Gy, respectively. The normal tissue within 12Gy physical dose region had an average 2Gy dose equivalent of 29.55Gy, 16.08Gy and 13.93Gy, respectively. Conclusion: The single fraction SRS plan had the largest predicted biological effect for the target and the surrounding normal tissue. The multi-stage treatment provided for a more potent biologically effect on target compared to the multi-fraction SRT treatments with less biological normal tissue than single-fraction SRS treatment

Design and analysis of a small-scale natural gas liquefaction process adopting single nitrogen expansion with carbon dioxide pre-cooling

International Nuclear Information System (INIS)

Yuan, Zongming; Cui, Mengmeng; Xie, Ying; Li, Chunlin

2014-01-01

With the growth of energy consumption and environmental protection concerns, it is of enormous economic and environmental values for the development of stranded gas. As a means for exploitation and transportation of stranded gas to market, a novel small-scale liquefaction process adopting single nitrogen expansion with carbon dioxide pre-cooling is put up with in this paper. Taking unit energy consumption as the target function, Aspen HYSYS is employed to simulate and optimize the process to achieve the liquefaction rate of 0.77 with unit energy consumption of 9.90 kW/kmol/h. Furthermore, the adaptability of this process under different pressure, temperature and compositions of feed gas is studied. Based on the optimization results, the exergy losses of main equipment in the process are evaluated and analyzed in details. With compact device, safety operation, simple capability, this liquefaction process proves to be suitable for the development of small gas reserves, satellite distribution fields of gas or coalbed methane fields. - Highlights: •A novel small-scale liquefaction process used in stranded gas is designed. •The adaptability of this process under different pressure, temperature and compositions of feed gas is studied. •The exergy analysis of main equipment in the process is analyzed

Design and analysis of a small-scale natural gas liquefaction process adopting single nitrogen expansion with carbon dioxide pre-cooling

Energy Technology Data Exchange (ETDEWEB)

Yuan, Zongming; Cui, Mengmeng; Xie, Ying; Li, Chunlin

2014-03-01

With the growth of energy consumption and environmental protection concerns, it is of enormous economic and environmental values for the development of stranded gas. As a means for exploitation and transportation of stranded gas to market, a novel small-scale liquefaction process adopting single nitrogen expansion with carbon dioxide pre-cooling is put up with in this paper. Taking unit energy consumption as the target function, Aspen HYSYS is employed to simulate and optimize the process to achieve the liquefaction rate of 0.77 with unit energy consumption of 9.90 kW/kmol/h. Furthermore, the adaptability of this process under different pressure, temperature and compositions of feed gas is studied. Based on the optimization results, the exergy losses of main equipment in the process are evaluated and analyzed in details. With compact device, safety operation, simple capability, this liquefaction process proves to be suitable for the development of small gas reserves, satellite distribution fields of gas or coalbed methane fields. - Highlights: •A novel small-scale liquefaction process used in stranded gas is designed. •The adaptability of this process under different pressure, temperature and compositions of feed gas is studied. •The exergy analysis of main equipment in the process is analyzed.

Prospects of Optical Single Atom Detection in Noble Gas Solids for Measurements of Rare Nuclear Reactions

Science.gov (United States)

Singh, Jaideep; Bailey, Kevin G.; Lu, Zheng-Tian; Mueller, Peter; O'Connor, Thomas P.; Xu, Chen-Yu; Tang, Xiaodong

2013-04-01

Optical detection of single atoms captured in solid noble gas matrices provides an alternative technique to study rare nuclear reactions relevant to nuclear astrophysics. I will describe the prospects of applying this approach for cross section measurements of the ^22Ne,,),25Mg reaction, which is the crucial neutron source for the weak s process inside of massive stars. Noble gas solids are a promising medium for the capture, detection, and manipulation of atoms and nuclear spins. They provide stable and chemically inert confinement for a wide variety of guest species. Because noble gas solids are transparent at optical wavelengths, the guest atoms can be probed using lasers. We have observed that ytterbium in solid neon exhibits intersystem crossing (ISC) which results in a strong green fluorescence (546 nm) under excitation with blue light (389 nm). Several groups have observed ISC in many other guest-host pairs, notably magnesium in krypton. Because of the large wavelength separation of the excitation light and fluorescence light, optical detection of individual embedded guest atoms is feasible. This work is supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

Variable geometry gas turbines for improving the part-load performance of marine combined cycles - Gas turbine performance

DEFF Research Database (Denmark)

Haglind, Fredrik

2010-01-01

The part-load performance of gas and steam turbine combined cycles intended for naval use is of great importance, and it is influenced by the gas turbine configuration and load control strategy. This paper is aimed at quantifying the effects of variable geometry on the gas turbine part...... of various components within gas turbines. Two different gas turbine configurations are studied, a two-shaft aero-derivative configuration and a single-shaft industrial configuration. When both gas turbine configurations are running in part-load using fuel flow control, the results indicate better part......-load performance for the two-shaft gas turbine. Reducing the load this way is accompanied by a much larger decrease in exhaust gas temperature for the single-shaft gas turbine than for the two-shaft configuration. As used here, the results suggest that variable geometry generally deteriorates the gas turbine part...

Method and apparatus for producing synthesis gas

Science.gov (United States)

Hemmings, John William; Bonnell, Leo; Robinson, Earl T.

2010-03-03

A method and apparatus for reacting a hydrocarbon containing feed stream by steam methane reforming reactions to form a synthesis gas. The hydrocarbon containing feed is reacted within a reactor having stages in which the final stage from which a synthesis gas is discharged incorporates expensive high temperature materials such as oxide dispersed strengthened metals while upstream stages operate at a lower temperature allowing the use of more conventional high temperature alloys. Each of the reactor stages incorporate reactor elements having one or more separation zones to separate oxygen from an oxygen containing feed to support combustion of a fuel within adjacent combustion zones, thereby to generate heat to support the endothermic steam methane reforming reactions.

CLOSING MACULAR HOLES WITH "MACULAR PLUG" WITHOUT GAS TAMPONADE AND POSTOPERATIVE POSTURING.

Science.gov (United States)

Chakrabarti, Meena; Benjamin, Preethi; Chakrabarti, Keya; Chakrabarti, Arup

2017-03-01

To investigate the surgical results of macular hole surgery without gas tamponade or postoperative posturing in patients with Stage 3 and Stage 4 macular holes with ≥500 μm mean base diameter. Retrospective interventional case series. Twenty-six patients with Stage 3 and Stage 4 macular holes. Twenty-six eyes of 26 patients with Stage 3 and Stage 4 macular holes and a mean base diameter of 892.8 ± 349 μm underwent pars plana 23-gauge vitrectomy with broad internal limiting membrane peel (ILM peel), inverted ILM flap repositioning (ILMR), and use of autologous gluconated blood clumps as a macular plug to close the macular hole. No fluid-air exchange, endotamponade, or postoperative posturing was used. The subjects were followed up for 12 months. The anatomical outcome of the procedure was evaluated by fundus examination and optical coherence tomography. Spectral domain optical coherence tomography was used to study the restoration of the outer retinal layer integrity in the postoperative period. The preoperative and postoperative best-corrected visual acuities in logMAR units were compared to evaluate functional outcome. Macular hole closure and best-corrected visual acuity before and after surgery. Twenty-six patients with mean age 62.8 ± 7.3 years, preoperative median best-corrected visual acuity 6/60 (1.0 logMAR units), and a mean base diameter of 892.8 ± 349 μm underwent surgery to close macular holes without gas tamponade or postoperative posturing. Twenty patients (76.9%) were phakic. Twenty eyes (76.92%) had Stage 3 macular holes and 6 eyes (23.10%) had Stage 4 macular holes. After a single surgery, hole closure was achieved in 100% of eyes. The median best-corrected visual acuity improved from 6/60 (1.0 logMAR units) to 6/18 (0.50 logMAR units) (P hole closure with statically significant functional improvement for large Stage 3 and Stage 4 macular holes.

A Cost-Effective Power Ramp-Rate Control Strategy for Single-Phase Two-Stage Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

In the case of a wide-scale adoption of grid-connected Photovoltaic (PV) systems, more fluctuated power will be injected into the grid due to the intermittency of solar PV energy. A sudden change in the PV power can potentially induce grid voltage fluctuations, and thus challenge the stability......-point. Experiments conducted on a 3-kW single-phase two-stage grid-connected PV system have verified that the proposed solution can accomplish fast dynamics, high accuracy, and high robustness in the power ramp-rate control for PV systems....

Asian gas

International Nuclear Information System (INIS)

Masuda, T.

1990-01-01

This paper reports on natural gas which now appears ready to take a leading role on the world energy stage. Demand for natural gas, and specifically LNG, will be strong throughout the world, particularly in Asia. Indonesia and Malaysia will become much more dependent on natural gas in the Asian market. In Thailand, where remarkable economic growth has been fueled by imported oil and domestically produced natural gas, LNG may soon have to be imported from neighboring countries. The author sees Thailand's imports of natural gas increasing from 1.5 to 4.5 million tons annually. Similarly, Korea's imports of LNG will rise from 2 to 8 million tons between 1987 and 2000. In Japan, energy demand is expected to increase at an even faster rate in the 1990s. Given the opposition to nuclear power generation and growing concern about the greenhouse effect, it is likely that LNG will satisfy a major portion of Japan's increasing demand for energy. Japanese gas companies are studying the possibility of establishing a national pipeline network to move gas beyond metropolitan areas

Transient Analysis of a Gas-cooled Fast Reactor for Single Control Assembly Withdrawal

International Nuclear Information System (INIS)

Choi, Hangbok

2014-01-01

The Energy Multiplier Module (EMZ) system response has been evaluated for control assembly withdrawal transients. Currently the EM2 core is equipped with six cylindrical drum-type control assemblies in the reflector zone for excess reactivity control and power maneuvering during the operating core life. This study investigates the system response to the control assembly withdrawal accident with various rotational speeds and reactivity worth to determine feasible control assembly design requirements from the physics viewpoint. The simulations have been conducted for single control assembly withdrawal transients without scram by a gas-cooled reactor plant simulator, which is based on a simplified plant nodal model, including the point reactor kinetics, single channel core thermal-fluid model, and a turbo-machinery performance model. Simulations were conducted for the middle-of- cycle core, when the excess reactivity of the core is the highest. Control assembly withdrawal times were varied from 1 (runaway) to 180 sec and reactivity worth was varied from 100 to 400 pcm. For a single control assembly withdrawal, the simulation has shown that the peak fuel temperature is expected to be ~1820°C when the assembly worth is 200 pcm and the runaway time is 1 sec per 180 degree rotation. The peak temperature could be reduced to ~1780°C if the assembly is rotated out in a moderate speed such as 1 degree/sec. These peak temperatures give a thermal margin of 22 to 24% to the melting point of uranium carbide fuel. The results also indicate that the current design with a single control assembly worth of 314 pcm may need adjustments in the future design. (author)

Single-stage anaerobic treatment of non-settled slaughterhouse waste water using a fixed-bed reactor. Einstufige anaerobe Behandlung von nicht abgesetztem Schlachthofabwasser in einem Festbettreaktor

Energy Technology Data Exchange (ETDEWEB)

Tritt, W.P. (Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (Germany). Inst. fuer Technologie); Meyer-Jacob, H.

1992-01-01

Along with the determination of the degree of acidification during an intermediate storage of the crude slaughterhouse wastewater and deriving a single-stage or two-stage process, the start-up behaviour of the fixed-bed reactor, its degradation rates in upflow and downflow operation is descirbed. With regard to a subsequent biological denitrification the COD/N ratio of anaerobically treated wastewater is given. (orig.).

Pros and cons of an expansion of the natural gas system in the Nordic Countries - sensitivity analysis of the scenario results from stage one of the Nordleden project

International Nuclear Information System (INIS)

2001-12-01

The report shows that the maximum economic profit from a transnordic gas grid amounts to 5-30 billion SEK (0.5-3 billion USD), depending on scenarios. This holds even under relatively strict CO 2 limitations. The profit is in the same range as the profits from emissions trading or from free trade in electricity in the Nordic market. In absolute numbers, the profit increases with increased energy demand. The natural gas supply could amount to about 300 TWh in year 2030, if the price at the border does not surpass 70 SEK/MWh (7 USD/MWh). The main expansion would be in central power and heat production. However, the report also shows that the transnordic gas grid could become a burden for the Nordic energy system, as the profit could be negative in the case where the investment is done according to the design case, but the gas price gets higher. The worst case could result in a loss of about 30 billion SEK. However, it is probably more realistic to assume that the market actors try to minimize their own risks through long term contracts with fixed prices and volumes, leading to a transfer of the risk to the society as a whole, being forced to renounce cheaper solutions for reaching the environmental goals in the case where natural gas becomes a more expensive fuel than supposed in the planning stage. The corresponding risk is much lower from a CO 2 point of view, i.e. if future CO 2 reduction limit become more strict than in the planning stage, the value of the gas grid is only marginally affected. Sensitivity analysis where the Nordic cooperation is widened to include trade in electricity (which already is a fact) and emission rights show that the optimum natural gas supply is affected, but to a small degree only. The net effect is a certain redistribution of the natural gas use between the countries

The method of the gas-dynamic centrifugal compressor stage characteristics recalculation for variable rotor rotational speeds and the rotation angle of inlet guide vanes blades if the kinematic and dynamic similitude conditions are not met

Science.gov (United States)

Vanyashov, A. D.; Karabanova, V. V.

2017-08-01

A mathematical description of the method for obtaining gas-dynamic characteristics of a centrifugal compressor stage is proposed, taking into account the control action by varying the rotor speed and the angle of rotation of the guide vanes relative to the "basic" characteristic, if the kinematic and dynamic similitude conditions are not met. The formulas of the correction terms for the non-dimensional coefficients of specific work, consumption and efficiency are obtained. A comparative analysis of the calculated gas-dynamic characteristics of a high-pressure centrifugal stage with experimental data is performed.

Acceleration of small, light projectiles (including hydrogen isotopes) to high speeds using a two-stage light gas gun

International Nuclear Information System (INIS)

Combs, S.K.; Foust, C.R.; Gouge, M.J.; Milora, S.L.

1989-01-01

Small, light projectiles have been accelerated to high speeds using a two-stage light gas gun at Oak Ridge National Laboratory. With 35-mg plastic projectiles (4 mm in diameter), speeds of up to 4.5 km/s have been recorded. The ''pipe gun'' technique for freezing hydrogen isotopes in situ in the gun barrel has been used to accelerate deuterium pellets (nominal diameter of 4 mm) to velocities of up to 2.85 km/s. The primary application of this technology is for plasma fueling of fusion devices via pellet injection of hydrogen isotopes. Conventional pellet injectors are limited to pellet speeds in the range 1-2 km/s. Higher velocities are desirable for plasma fueling applications, and the two-stage pneumatic technique offers performance in a higher velocity regime. However, experimental results indicate that the use of sabots to encase the cryogenic pellets and protect them for the high peak pressures will be required to reliably attain intact pellets at speeds of ∼3 km/s or greater. In some limited tests, lithium hydride pellets were accelerated to speeds of up to 4.2 km/s. Also, repetitive operation of the two-stage gun (four plastic pellets fired at ∼0.5 Hz) was demonstrated for the first time in preliminary tests. The equipment and operation are described, and experimental results and some comparisons with a theoretical model are presented. 17 refs., 6 figs., 2 tabs

Cold, warm, and hot gas in the late-stage merger NGC 7252

Science.gov (United States)

Hibbard, J. E.; Guhathakurta, Puragra; van Gorkom, J. H.; Schweizer, Francois

1994-01-01

We present the first observations of the neutral hydrogen distribution and x-ray emission in the prototypical merger remnant NGC 7252, the 'Atoms-for-Peace' galaxy. These data are supplemented by accurate B and R surface photometry, reaching a limit of muB = 26.5 mag/sq arcsec, and images taken through a narrow-band H alpha filter. We find all of the 2 x 109/sq h solar mass of atomic gas to be restricted to the outer, tidal regions of this system (Hzero = 100 h km/s/Mpc). By contrast, the molecular gas traced by the (12)CO(1 approaches zero) map of Wang et al. (1992) is confined to an inner rotating disk of radius 7 seconds and has an H alpha counterpart. The gap between the atomic and molecular gas distributions is filled in by diffuse H alpha emission and perhaps by x-ray emission. The velocity field of the atomic gas in the tidal tails indicates that they are swinging through space in the same sense as the rotation of the inner gas disk. The H I at the apparent base of the northwestern tail seems to be falling back toward the main body of the galaxy, yet there is no H I associated with this main stellar body: This suggests ongoing efficient conversion of the atomic gas into other phases in this region. The H alpha velocity anomalies previously found in the remnant body may be produced in part by the combination of tail-related, noncircular motions and the inner gas-disk rotation. Both tidal tails have bluer B-R colors than the main body of the remnant, with the bluest regions coinciding with peaks in the gas column density. Each tail contains one giant H II region near the end of its optical light distribution. These H II regions are associated with large concentrations of gas and stars that approach the sizes and gas contents of dwarf galaxies. The H I extends beyond the end of the optical tails and reaches projected distances of 62/h kpc east and 120/h kpc northwest from the center. We discuss the possible relevance of these data to : (1) the transformation of

Stimulating shale gas development in China: A comparison with the US experience

International Nuclear Information System (INIS)

Tian, Lei; Wang, Zhongmin; Krupnick, Alan; Liu, Xiaoli

2014-01-01

In this paper, we use the US shale gas experience to shed light on how China might overcome the innovation problem inherent in exploring and developing shale gas plays with complex geology. We separate shale gas development into two stages, an innovation stage and a scaling-up stage, with the first presenting a much bigger challenge than the latter. Our analysis suggests that China's national oil companies offer the best hope for overcoming the innovation problem. China's policy of opening shale gas development to new entrants is a market-oriented reform that can be justified on various grounds, but the new entrants will not play a major role in overcoming the innovation problem even though they may help scale up production later on. - Highlights: • We separate shale gas development into an innovation stage and a scaling up stage. • We use the US experience to elucidate how China may solve the innovation problem. • China has to rely on its national oil companies to solve the innovation problem. • Opening shale gas development to new entrants can be justified on several grounds. • New entrants will not help overcome the innovation problem

Two-stage combustion, a new concept in reducing alkali related operational problem; Tvaastegsfoerbraenning, ett nytt koncept att minska alkalirelaterad driftproblematik

Energy Technology Data Exchange (ETDEWEB)

Hjoernhede, Anders; Hermansson, Sven; Seemann, Martin; Alamia, Alberto; Larsson, Anton; Davidsson, Kent; Niklasson, Fredrik; Atongka Tchoffor, Placid; Jones, Frida

2012-07-01

A possible way to reduce alkali related problems during thermal conversion of fuels into heat and power is to thermally split the fuel into a relatively alkali-lean gas stream and a relatively alkali-rich char stream. The alkali-lean gas stream could then be combusted and used for high-temperature purpose, e.g. superheating of steam. The char residue could be combusted for heating of e.g. steam tubes at inferior temperatures. The purpose of this project has been to study and demonstrate such two-stage combustion, with separation of the early devolatilization from alkali-rich fuels for steam superheating. Within the project, it has been investigated if this type of thermal conversion is thermo-economically feasible. Furthermore, it has been investigated in laboratory and pilot scale trials, which kinds of fuels, temperature levels and fuel residence times that are required to achieve a flue gas with significantly lower concentrations of alkaloids, compared to single-stage conversion. The results from the thermo-economical simulations show that it is possible to arrange the heat exchanger surfaces in a power plant for thermal two-stage conversion. Compared to traditional one-stage combustion, the electricity efficiency could be increased from 35 % to more than 38 %. However, the results from combustion, gasification and pyrolysis in lab, together with gasification trials in the Chalmers pilot plant, show that the investigated woody fuels (bark and wood pellets) do not seem to be feasible for two-stage conversion. These fuels emit alkaloids exclusively in conjunction with the devolatilization in opposite to the desired effect. On the other hand, straw is a potential fuel candidate for two-stage conversion, since straw emits alkaloids during both devolatilization and char conversion. Furthermore, the results show that increased temperature generally causes increased alkali release. From the results it is suggested that the propensity of a fuel to release alkali during

A safety equipment list for rotary mode core sampling systems operation in single shell flammable gas tanks; TOPICAL

International Nuclear Information System (INIS)

SMALLEY, J.L.

1999-01-01

This document identifies all interim safety equipment to be used for rotary mode core sampling of single-shell flammable gas tanks utilizing Rotary Mode Core Sampling systems (RMCS). This document provides the safety equipment for RMCS trucks HO-68K-4600, HO-68K-4647, trucks three and four respectively, and associated equipment. It is not intended to replace or supersede WHC-SD-WM-SEL-023, (Kelly 1991), or WHC-SD-WM-SEL-032, (Corbett 1994), which classifies 80-68K-4344 and HO-68K-4345 respectively. The term ''safety equipment'' refers to safety class (SC) and safety significant (SS) equipment, where equipment refers to structures, systems and components (SSC's). The identification of safety equipment in this document is based on the credited design safety features and analysis contained in the Authorization Basis (AB) for rotary mode core sampling operations in single-shell flammable gas tanks. This is an interim safety classification since the AB is interim. This document will be updated to reflect the final RMCS equipment safety classification designations upon completion of a final AB which will be implemented with the release of the Final Safety Analysis Report (FSAR)

Multi Stage Strategies for Single Point Incremental Forming of a Cup

DEFF Research Database (Denmark)

Skjødt, Martin; Bay, Niels; Endelt, Benny

2008-01-01

A five stage forming strategy for forming of a circular cylindrical cup with a height/radius ratio of one is presented. Geometrical relations are discussed and theoretical strains are calculated. The influence of forming direction (upwards or downwards) is investigated for the second stage...... comparing explicit FE analysis with experiments. Good agreement is found between calculated and measured thickness distribution, overall geometry and strains. Using the proposed multi stage strategy it is shown possible to produce a cup with a height close to the radius and side parallel to the symmetry...

Assessment of greenhouse gas emissions from natural gas

International Nuclear Information System (INIS)

Anon

2000-01-01

The study, 'Assesment of greenhouse gas emission from natural gas' by independent consultants Energetics Pty Ltd, shows that natural gas has significantly fewer greenhouses gas emissions than either black or brown cola for the defined life cycle stages. The life cycle emissions from natural gas use by an Australian Major User are approximately 50% less than the emissions from Victorian brown coal and approximately 38% less than the emissions from Australian average black coal. Australian Best Practice gas fired electricity generation is estimated to emit between 514 and 658 kg CO 2 e/MWh. By comparison, Australian Best Practice coal-fired electricity generation is estimated to emit between 907 and 1,246 kg CO 2 e/MWh for black and brown coal respectively. Greenhouse gas emissions from Australian Best Practice gas-fired electricity generation using combined cycle gas turbines (including full fuel cycle emissions) vary from 41% to 46% of the emissions from brown coal-fired electricity generation and 57% to 64% of emissions from black coal-fired electricity generation. Greenhouse gas emissions from direct gas supply water heating range from 1,470 to 2,042 kilograms per annum. This compares with emissions of 1,922 to 2,499 kg for electric heating from gas-fired electricity generation and 3,975 to 5,393 kg for coal-fired electricity generation. The implications for greenhouse policy nationally are also discussed, emphasising the need to review national energy policy, currently tied to 'fuel neutrality' doctrine

Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

International Nuclear Information System (INIS)

Combs, S.K.; Milora, S.L.; Foust, C.R.; Gouge, M.J.; Fehling, D.T.; Sparks, D.O.

1988-01-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-l volume (/ 3 for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of ∼3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications. 25 refs., 6 figs., 1 tab

The gas-chromatographic and gas-chromatographic-mass-spectrometric identification of halogen-containing organic compounds

Science.gov (United States)

Gidaspov, B. V.; Zenkevich, I. G.; Rodin, A. A.

1989-09-01

The problem of identifying halogen-containing organic compounds in their gas-chromatographic and gas-chromatographic-mass-spectrometric (GC-MS) determination in different materials has been examined. Particular attention has been paid not to the complete characterisation of methods for carrying out this analysis but to the most important problem of increasing the selectivity at the stages of sampling, separation, and interpretation of the gas-chromatographic and GC-MS information. The bibliography contains 292 references.

Gas Production Strategy of Underground Coal Gasification Based on Multiple Gas Sources

Directory of Open Access Journals (Sweden)

Duan Tianhong

2014-01-01

Full Text Available To lower stability requirement of gas production in UCG (underground coal gasification, create better space and opportunities of development for UCG, an emerging sunrise industry, in its initial stage, and reduce the emission of blast furnace gas, converter gas, and coke oven gas, this paper, for the first time, puts forward a new mode of utilization of multiple gas sources mainly including ground gasifier gas, UCG gas, blast furnace gas, converter gas, and coke oven gas and the new mode was demonstrated by field tests. According to the field tests, the existing power generation technology can fully adapt to situation of high hydrogen, low calorific value, and gas output fluctuation in the gas production in UCG in multiple-gas-sources power generation; there are large fluctuations and air can serve as a gasifying agent; the gas production of UCG in the mode of both power and methanol based on multiple gas sources has a strict requirement for stability. It was demonstrated by the field tests that the fluctuations in gas production in UCG can be well monitored through a quality control chart method.

Test and evaluate the tri-gas low-Btu coal-gasification process. Final report, October 21, 1977-October 31, 1980

Energy Technology Data Exchange (ETDEWEB)

Zabetakis, M.G.

1980-12-01

This report describes the continuation of work done to develop the BCR TRI-GAS multiple fluidized-bed gasification process. The objective is the gasification of all ranks of coals with the only product being a clean, low-Btu fuel gas. Design and construction of a 100 lb/h process and equipment development unit (PEDU) was completed on the previous contract. The process consists of three fluid-bed reactors in series, each having a specific function: Stage 1 - pretreatment; Stage 2- - gasification; Stage 3 - maximization of carbon utilization. Under the present contract, 59 PEDU tests have been conducted. A number of these were single-stage tests, mostly in Stage 1; however, integrated PEDU tests were conducted with a western coal (Rosebud) and two eastern coals (Illinois No. 6 and Pittsburgh seam). Both Rosebud and Pittsburgh seam coals were gasified with the PEDU operating in the design mode. Operation with Illinois No. 6 seam coal was also very promising; however, time limitations precluded further testing with this coal. One of the crucial tasks was to operate the Stage 1 reactor to pretreat and devolatilize caking coals. By adding a small amount of air to the fluidizing gas, the caking properties of the coal can be eliminated. However, it was also desirable to release a high percentage of the volatile matter from the coal in this vessel. To accomplish this, the reactor had to be operated above the agglomerating temperature of caking coals. By maintaining a low ratio of fresh to treated coal, this objective was achieved. Both Illinois No. 6 and Pittsburgh seam coals were treated at temperatures of 800 to 900 F without agglomerating in the vessel.

Novel process chain for hot metal gas forming of ferritic stainless steel 1.4509

Science.gov (United States)

Mosel, André; Lambarri, Jon; Degenkolb, Lars; Reuther, Franz; Hinojo, José Luis; Rößiger, Jörg; Eurich, Egbert; Albert, André; Landgrebe, Dirk; Wenzel, Holger

2018-05-01

Exhaust gas components of automobiles are often produced in ferritic stainless steel 1.4509 due to the low thermal expansion coefficient and the low material price. Until now, components of the stainless steel with complex geometries have been produced in series by means of multi-stage hydroforming at room temperature with intermediate annealing operations. The application of a single-stage hot-forming process, also referred to as hot metal gas forming (HMGF), offers great potential to significantly reduce the production costs of such components. The article describes a novel process chain for the HMGF process. Therefore the tube is heated in two steps. After pre-heating of the semi-finished product outside the press, the tube is heated up to forming start temperature by means of a tool-integrated conductive heating before forming. For the tube of a demonstrator geometry, a simulation model for the conduction heating was set up. In addition to the tool development for this process, experimental results are also described for the production of the demonstrator geometry.

Cumulative Distributions and Flow Structure of Two-Passage Shear Coaxial Injector with Various Gas Injection Ratio

Energy Technology Data Exchange (ETDEWEB)

Lee, Inchul; Kim, Dohun; Koo, Jaye [Korea Aerospace Univ., Goyang (Korea, Republic of)

2013-07-15

To verify the effect of inner- and outer-stage gas jets, a shear coaxial injector was designed to analyze the axial velocity profile and breakup phenomenon with an increase in the measurement distance. When the measurement position was increased to Z/d=100, the axial flow showed a fully developed shape due to the momentum transfer, aerodynamic drag effect, and viscous mixing. An inner gas injection, which induces a higher momentum flux ratio near the nozzle, produces the greater shear force on atomization than an outer gas injection. Inner- and Outer-stage gas injection do not affect the mixing between the inner and outer gas flow below Z/d=5. The experiment results showed that the main effect of liquid jet breakup was governed by the gas jet of an inner stage. As the nozzle exit of the outer-stage was located far from the liquid column, shear force and turbulence breaking up of the liquid jets do not fully affect the liquid column. In the case of an inner-stage gas injection momentum flux ratio within 0.84, with the increase in the outer gas momentum flux ratio, the Smd decreases. However, at an inner-stage gas jet momentum flux ratio over 1.38, the Smd shows the similar distribution.

Natural gas applications in waste management

International Nuclear Information System (INIS)

Tarman, P.B.

1991-01-01

The Institute of Gas Technology (IGT) is engaged in several projects related to the use of natural gas for waste management. These projects can be classified into four categories: cyclonic incineration of gaseous, liquid, and solid wastes; fluidized-bed reclamation of solid wastes; two-stage incineration of liquid and solid wastes; natural gas injection for emissions control. 5 refs., 8 figs

Characteristics and Sampling Efficiencies of Two Impactor Bioaerosol Samplers: MAS-100(Registered) (Microbial Air Monitoring System) and Single-Stage Andersen Viable Microbial Samplers

National Research Council Canada - National Science Library

Hottell, K

2004-01-01

.... A petri dish with agar is used as the impaction surface for these samplers. The MAS-l00 is a single-stage impactor that aspirates air through a 400-hole perforated entry plate onto an agar plate at an airflow rate of 100 L/min...

Two-stage thermal/nonthermal waste treatment process

International Nuclear Information System (INIS)

Rosocha, L.A.; Anderson, G.K.; Coogan, J.J.; Kang, M.; Tennant, R.A.; Wantuck, P.J.

1993-01-01

An innovative waste treatment technology is being developed in Los Alamos to address the destruction of hazardous organic wastes. The technology described in this report uses two stages: a packed bed reactor (PBR) in the first stage to volatilize and/or combust liquid organics and a silent discharge plasma (SDP) reactor to remove entrained hazardous compounds in the off-gas to even lower levels. We have constructed pre-pilot-scale PBR-SDP apparatus and tested the two stages separately and in combined modes. These tests are described in the report

Wind-driven SEIG supplying DC microgrid through a single-stage power converter

Directory of Open Access Journals (Sweden)

Vellapatchi Nayanar

2016-09-01

Full Text Available Nowadays, there is an increased emphasis on utilizing the renewable energy sources and selection of suitable power converters for supplying dc microgrid. Among the various renewable energy sources, wind energy stands first in terms of installed capacity. So, an attempt is made in this paper for supplying dc microgrid utilizing wind energy. A self-excited induction generator has been used in the proposed wind energy conversion system (WECS. A single-stage power converter, namely, semi-converter is connected between the SEIG and dc grid terminals for closed-loop control of the proposed system. A perturb and observe (P&O based maximum power point tracking (MPPT algorithm has been developed and implemented using a dsPIC30F4011 digital controller. In this MPPT algorithm, the firing angle of the converter is adjusted by continuously monitoring the dc grid current for a given wind velocity. For analyzing the proposed system, a MATLAB/Simulink model has been developed by selecting the various components starting from wind-turbine model to the power converter supplying dc microgrid. Successful working of the proposed WECS has also been shown through experimental results obtained on a prototype model developed in the laboratory.

Early-stage aggregation in three-dimensional charged granular gas

Science.gov (United States)

Singh, Chamkor; Mazza, Marco G.

2018-02-01

Neutral grains made of the same dielectric material can attain considerable charges due to collisions and generate long-range interactions. We perform molecular dynamic simulations in three dimensions for a dilute, freely cooling granular gas of viscoelastic particles that exchange charges during collisions. As compared to the case of clustering of viscoelastic particles solely due to dissipation, we find that the electrostatic interactions due to collisional charging alter the characteristic size, morphology, and growth rate of the clusters. The average cluster size grows with time as a power law, whose exponent is relatively larger in the charged gas than the neutral case. The growth of the average cluster size is found to be independent of the ratio of characteristic Coulomb to kinetic energy, or equivalently, of the typical Bjerrum length. However, this ratio alters the crossover time of the growth. Both simulations and mean-field calculations based on Smoluchowski's equation suggest that a suppression of particle diffusion due to the electrostatic interactions helps in the aggregation process.

Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

International Nuclear Information System (INIS)

Yoosefian, Mehdi

2017-01-01

Highlights: • Investigation of the adsorption of Nitrous oxide on SWCNT and Pd/SWCNT. • Nitrous oxide adsorbed on Pd/SWCNT system demonstrates a strong adsorption. • The Pd/SWCNT is potential sensor for the Nitrous oxide gaseous molecule detection. - Abstract: Density functional studies on the adsorption behavior of nitrous oxide (N_2O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N_2O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N_2O onto CNT, the horizontal adsorption with E_a_d_s = −0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N_2O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N_2O were investigated. Adsorption of N_2O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N_2O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N_2O sensors.

Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

Energy Technology Data Exchange (ETDEWEB)

Yoosefian, Mehdi, E-mail: m.yoosefian@kgut.ac.ir

2017-01-15

Highlights: • Investigation of the adsorption of Nitrous oxide on SWCNT and Pd/SWCNT. • Nitrous oxide adsorbed on Pd/SWCNT system demonstrates a strong adsorption. • The Pd/SWCNT is potential sensor for the Nitrous oxide gaseous molecule detection. - Abstract: Density functional studies on the adsorption behavior of nitrous oxide (N{sub 2}O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N{sub 2}O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N{sub 2}O onto CNT, the horizontal adsorption with E{sub ads} = −0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N{sub 2}O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N{sub 2}O were investigated. Adsorption of N{sub 2}O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N{sub 2}O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N{sub 2}O sensors.

Single-Stage Treatment of Osteomyelitis for Digital Salvage by Using an Antibiotic-Eluting, Methylmethacrylate Joint-Spanning Spacer.

Science.gov (United States)

Aimé, Victoria L; Kidwell, John T; Webb, Leland H

2017-06-01

Osteomyelitis of the digit is a challenging problem that can result in amputation. We describe 13 cases of osteomyelitis involving bones of the hand managed with a novel technique. We reviewed records of 12 patients (13 digits) who had joint-spanning, antibiotic-eluting (tobramycin or vancomycin), methylmethacrylate spacers placed as definitive, single-stage treatment for digital osteomyelitis. The primary outcome was digit salvage. Secondary outcomes were infection eradication (no recurrence at 3 months) and spacer removal. Patients were followed up until the infection resolved (ie, no cutaneous signs of infection, including pain, erythema, or swelling). At a mean of 24 months, 10 of 13 infections had successful one-stage treatment. One patient required a second operation to revise a soft tissue flap but the spacer remained in place. Two spacers were removed because of malalignment. An antibiotic-eluting methylmethacrylate spacer is an innovative treatment for digital osteomyelitis. In 12 consecutive patients (13 digits), we successfully salvaged the digit. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Exergy analysis of a gas-hydrate cool storage system

International Nuclear Information System (INIS)

Bi, Yuehong; Liu, Xiao; Jiang, Minghe

2014-01-01

Based on exergy analysis of charging and discharging processes in a gas-hydrate cool storage system, the formulas for exergy efficiency at the sensible heat transfer stage and the phase change stage corresponding to gas-hydrate charging and discharging processes are obtained. Furthermore, the overall exergy efficiency expressions of charging, discharging processes and the thermodynamic cycle of the gas-hydrate cool storage system are obtained. By using the above expressions, the effects of number of transfer units, the inlet temperatures of the cooling medium and the heating medium on exergy efficiencies of the gas-hydrate cool storage system are emphatically analyzed. The research results can be directly used to evaluate the performance of gas-hydrate cool storage systems and design more efficient energy systems by reducing the sources of inefficiency in gas-hydrate cool storage systems. - Highlights: • Formulas for exergy efficiency at four stages are obtained. • Exergy efficiency expressions of two processes and one cycle are obtained. • Three mainly influencing factors on exergy efficiencies are analyzed. • With increasing the inlet temperature of cooling medium, exergy efficiency increases. • With decreasing the inlet temperature of heating medium, exergy efficiency increases

Feasibility of a single-stage tracheostomy decannulation protocol with endoscopy in adult patients.

Science.gov (United States)

Cohen, Oded; Tzelnick, Sharon; Lahav, Yonatan; Stavi, Dekel; Shoffel-Havakuk, Hagit; Hain, Moshe; Halperin, Doron; Adi, Nimrod

2016-09-01

Gradual decrease in tube size and tube capping are considered the standard of care for tracheostomy decannulation. Both of these actions result in increased airway resistance. Immediate decannulation may offer a more tolerable approach. To assess the feasibility of immediate tracheostomy decannulation compared with the traditional decannulation methods. This study is a single institute, case-control retrospective study of patients between the years 2009 to 2014. The study group included all patients who underwent immediate decannulation, whereas the control group comprised patients who underwent traditional staged decannulation. An immediate decannulation protocol included admission to the intensive care unit, a comprehensive evaluation, decannulation, 24 hours of monitoring, and observation until discharge. Twenty-nine patients were included in the study group and 20 in the control group. No significant statistical difference was found between the two groups in the patients' medical history and tracheostomy data, except for the Acute Physiology and Chronic Health Evaluation II score and duration of the deflated cuff, which were significantly higher in the control group. A significant difference was found in the complication rate between the groups. In the staged decannulation group, four patients failed decannulation and required reinsertion of the tracheostomy cannula, whereas there were no such failures in the immediate decannulation group. Hospitalization duration after decannulation of the study group patients was significantly shorter than that of the control group. Immediate decannulation may offer a safe alternative for weaning from tracheostomy. It may also reduce the duration of the weaning process and hospitalization. 3b Laryngoscope, 126:2057-2062, 2016. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

The relation between photoluminescence properties and gas pressure with [0001] InGaN single quantum well systems

Energy Technology Data Exchange (ETDEWEB)

Tsutsumi, Toshiaki [Department of Nanosystem Sciences, Yokohama City University, Yokohama 236-0027 (Japan); Alfieri, Giovanni; Kawakami, Yoichi [Department of Electronic Science and Engineering, Kyoto University, Kyotodaigaku-katsura, Nishikyo, Kyoto 615-8510 (Japan); Micheletto, Ruggero, E-mail: ruggero@yokohama-cu.ac.jp [Department of Nanosystem Sciences, Yokohama City University, Yokohama 236-0027 (Japan)

2017-01-15

Highlights: • Photoluminescence of InGaN device is variable, there is no clear explanation for this. • We perform an ad-hoc absorption procedure, found that gases on the surface reduce emission. • We found that variability is related to the pressure of the gas in which the sample is immersed. • We point out the role of oxygen as major player in the reduction of photoluminescence. • A model is proposed and explains successfully the dynamical optical processes observed. - Abstract: We show for the first time that photoluminescence of InGaN single quantum wells (SQW) devices is related to the gas pressure in which the sample is immersed, also we give a model of the phenomena to suggest a possible cause. Our model shows a direct relation between experimental behavior and molecular coverage dynamics. This strongly suggests that the driving force of photoluminescence decrease is oxygen covering the surface of the device with a time dynamics that depends on the gas pressure. This aims to contribute to the understanding of the physical mechanism of the so-called optical memory effect and blinking phenomenon observed in these devices.

Data supporting the validation of a simulation model for multi-component gas separation in polymeric membranes

Directory of Open Access Journals (Sweden)

Lorena Giordano

2016-12-01

The data were obtained using a model for simulating gas separation, described in the research article entitled “Interplay of inlet temperature and humidity on energy penalty for CO2 post-combustion capture: rigorous analysis and simulation of a single stage gas permeation process” (L. Giordano, D. Roizard, R. Bounaceur, E. Favre, 2016 [1]. The data were used to validate the model by comparison with literature results. Considering a membrane system based on feed compression only, data from the model proposed and that from literature were compared with respect to the molar composition of permeate stream, the membrane area and specific energy requirement, varying the feed pressure and the CO2 separation degree.

Multi-zone coupling productivity of horizontal well fracturing with complex fracture networks in shale gas reservoirs

Directory of Open Access Journals (Sweden)

Weiyao Zhu

2018-02-01

Full Text Available In this paper, a series of specific studies were carried out to investigate the complex form of fracture networks and figure out the multi-scale flowing laws of nano/micro pores–complex fracture networks–wellbore during the development of shale reservoirs by means of horizontal well fracturing. First, hydraulic fractures were induced by means of Brazilian splitting tests. Second, the forms of the hydraulic fractures inside the rock samples were observed by means of X-ray CT scanning to measure the opening of hydraulic fractures. Third, based on the multi-scale unified flowing model, morphological description of fractures and gas flowing mechanism in the matrix–complex fracture network–wellbore, the productivity equation of single-stage horizontal well fracturing which includes diffusion, slipping and desorption was established. And fourthly, a productivity prediction model of horizontal well multi-stage fracturing in the shale reservoir was established considering the interference between the multi-stage fracturing zones and the pressure drop in the horizontal wellbore. The following results were obtained. First, hydraulic fractures are in the form of a complex network. Second, the measured opening of hydraulic fractures is in the range of 4.25–453 μm, averaging 112 μm. Third, shale gas flowing in different shapes of fracture networks follows different nonlinear flowing laws. Forth, as the fracture density in the strongly stimulated zones rises and the distribution range of the hydraulic fractures in strongly/weakly stimulated zones enlarges, gas production increases gradually. As the interference occurs in the flowing zones of fracture networks between fractured sections, the increasing amplitude of gas production rates decreases. Fifth, when the length of a simulated horizontal well is 1500 m and the half length of a fracture network in the strongly stimulated zone is 100 m, the productivity effect of stage 10 fracturing is the

Trends in risks associated with gas

International Nuclear Information System (INIS)

Pequignot, H.; Bertin, M.

1980-01-01

'Gas' is regarded at present as one of the forms of energy which presents the least health problems. All studies comparing the hazards of the various forms of energy have come to the same conclusion. For reasons of method this article views the situation from the viewpoint of the responsibilities and liabilities of the gas undertakings. When the gas supplied to customers was produced from coal, the risks inherent in mining the coal were not added to those of the production and distribution of the gas. Likewise, the problems raised by the production and transport of petroleum products which may be used by the gas industry, apart from natural gas of course, will not be considered here. At the outset, three particular points deserve to be stressed: Hazards exist at the stage of use and not at that of production; in this respect, gas differs from nuclear power and coal and the problems of prevention are therefore quite different; The hazards have declined sharply in the course of the past 25 years, and even at the distribution stage they have become fewer than in the case of most other forms of energy; The collection of epidemiological data was, and still is, better than in other power industries

Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage

Energy Technology Data Exchange (ETDEWEB)

Mahesh Iyer; Shwetha Ramkumar; Liang-Shih Fan

2006-09-30

Enhancement in the production of high purity hydrogen from fuel gas, obtained from coal gasification, is limited by thermodynamics of the Water Gas Shift Reaction. However, this constraint can be overcome by concurrent water-gas shift (WGS) and carbonation reactions to enhance H{sub 2} production by incessantly driving the equilibrium-limited WGS reaction forward and in-situ removing the CO2 product from the gas mixture. The spent sorbent is then regenerated by calcining it to produce a pure stream of CO{sub 2} and CaO which can be reused. However while performing the cyclic carbonation and calcination it was observed that the CO{sub 2} released during the in-situ calcination causes the deactivation of the iron oxide WGS catalyst. Detailed understanding of the iron oxide phase diagram helped in developing a catalyst pretreatment procedure using a H{sub 2}/H{sub 2}O system to convert the deactivated catalyst back to its active magnetite (Fe{sub 3}O{sub 4}) form. The water gas shift reaction was studied at different temperatures, different steam to carbon monoxide ratios (S/C) 3:1, 2:1, 1:1 and different total pressures ranging from 0-300 psig. The combined water gas shift and carbonation reaction was investigated at temperatures ranging from 600-700C, S/C ratio of 3:1 to 1:1 and at different pressures of 0-300 psig and the calcium looping process was found to produce high purity hydrogen with in-situ CO{sub 2} capture.

Single-virus tracking approach to reveal the interaction of Dengue virus with autophagy during the early stage of infection

Science.gov (United States)

Chu, Li-Wei; Huang, Yi-Lung; Lee, Jin-Hui; Huang, Long-Ying; Chen, Wei-Jun; Lin, Ya-Hsuan; Chen, Jyun-Yu; Xiang, Rui; Lee, Chau-Hwang; Ping, Yueh-Hsin

2014-01-01

Dengue virus (DENV) is one of the major infectious pathogens worldwide. DENV infection is a highly dynamic process. Currently, no antiviral drug is available for treating DENV-induced diseases since little is known regarding how the virus interacts with host cells during infection. Advanced molecular imaging technologies are powerful tools to understand the dynamics of intracellular interactions and molecular trafficking. This study exploited a single-virus particle tracking technology to address whether DENV interacts with autophagy machinery during the early stage of infection. Using confocal microscopy and three-dimensional image analysis, we showed that DENV triggered the formation of green fluorescence protein-fused microtubule-associated protein 1A/1B-light chain 3 (GFP-LC3) puncta, and DENV-induced autophagosomes engulfed DENV particles within 15-min postinfection. Moreover, single-virus particle tracking revealed that both DENV particles and autophagosomes traveled together during the viral infection. Finally, in the presence of autophagy suppressor 3-methyladenine, the replication of DENV was inhibited and the location of DENV particles spread in cytoplasma. In contrast, the numbers of newly synthesized DENV were elevated and the co-localization of DENV particles and autophagosomes was detected while the cells were treated with autophagy inducer rapamycin. Taken together, we propose that DENV particles interact with autophagosomes at the early stage of viral infection, which promotes the replication of DENV.

Advantages of using a two-switch forward in single-stage power factor corrected power supplies

DEFF Research Database (Denmark)

Petersen, Lars

2000-01-01

A single-stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (discontinues conduction mode) and it is shown that this operation mode ensures the intermediate DC-bus to be controlled only by means of circuit...... supply has been implemented. The measured efficiency is between 85% and 88.5% in the range 30 W-500 W and the measured power factor at full load is 0.95....... parameters and therefore independent of load variations. The DCM operation often has a diminishing effect on the efficiency but by use of the two-switch topology high efficiency with minimum circuit complexity can be achieved in this mode. A 500 W 70 V prototype of the two-switch boost-forward PFC power...

Proseek single-plex protein assay kit system to detect sAxl and Gas6 in serological material of brain tumor patients

Directory of Open Access Journals (Sweden)

Heidi Jaksch-Bogensperger

2018-06-01

Full Text Available • The receptor tyrosine kinase (RTK Axl and its ligand Gas6 are critically involved in the pathogenesis of high-grade glioma (HGG. Both proteins were found to be overexpressed e.g. in tumor cells, mediating cell proliferation and migration as well as tumor angiogenesis and neuroinflammation. The extracellular domain of Axl (sAxl and Gas6 were found in the peri-tumoral edema and blood of animals as well as in human glioma tissue. Therefore, we monitored the level of sAxl and Gas6 in human blood samples. To increase the sensitivity of protein detection beyond commonly used standard methods we preliminary tested the innovative Proseek Single-Plex Protein Assay Kit System from Olink Bioscience together with new antibodies against the soluble RTK sAxl and its ligand Gas6. We conclude that the Proseek method is a highly sensitive and fast procedure that can be used as a possible powerful tool compared to routinely used ELISA-methods.

A gas puff experiment for partial simulation of compact toroid formation on MARAUDER

International Nuclear Information System (INIS)

Englert, S.E.; Englert, T.J.; Degnan, J.H.; Gahl, J.M.

1994-01-01

Preliminary results will be reported of a single valve gas puff experiment to determine spatial and spectral distribution of a gas during the early ionization stages. This experiment has been developed as a diagnostic test-bed for partial simulation of compact toroid formation on MARAUDER. The manner in which the experimental hardware has been designed allows for a wide range of diagnostic access to evaluate early time evolution of the ionization process. This evaluation will help contribute to a clearer understanding of the initial conditions for the formation stage of the compact toroid in the MARAUDER experiment, where 60 of the same puff valves are used. For the experiment, a small slice of the MARAUDER cylindrical gas injection and expansion region geometry have been re-created but in cartesian coordinates. All of the conditions in the experiment adhere as closely as possible to the MARAUDER experiment. The timing, current rise time, capacitance, resistance and inductance are appropriate to both the simulation of one of the 60 puff valves and current delivery to the load. Both time-resolved images and spectral data have been gathered for visible light emission of the plasma. Processed images reveal characteristics of spatial distribution of the current. Spectral data provide information with respect to electron temperature and density, and entrainment of contaminants

Investigations of X-ray response of single wire anode Ar-N2 flow type gas scintillation proportional counters

International Nuclear Information System (INIS)

Garg, S.P.; Sharma, R.C.

1984-01-01

The X-ray response of single wire anode gas scintillation proportional counters of two different geometries operated with argon+nitrogen gases in continuous flow has been investigated with wire anodes of diameters 25 μm to 1.7 mm. An energy resolution of 19% is obtained for 5.9 keV X-rays entering the counter perpendicular to the anode in pill-box geometry with 25 μm diameter anode. With cylindrical geometry counters energy obtained at 5.9 keV are 18%, 24% and 33% for 50 μm, 0.5 mm and 1.7 mm diameter anodes respectively. An analysis of the observed resolution shows that the contribution from photon counting statistics to the relative variance of scintillation pulses even for X-rays in Ar-N 2 single wire anode gas scintillation proportional counters is small and is not a limiting factor. The energy resolution with thicker anodes, where the contribution from the variance of the charge multiplication factor also has been minimised, is found to deteriorate mainly by the interaction in the scintillation production region. Comments are made on the possibility of improvement in energy resolution by suppression of pulses due to such interactions with the help of the pulse risetime discrimination technique. (orig.)

Single stage: dorsolateral onlay buccal mucosal urethroplasty for long anterior urethral strictures using perineal route

Directory of Open Access Journals (Sweden)

Vikram Prabha

2016-06-01

Full Text Available ABSTRACT Objective To assess the outcome of single stage dorsolateral onlay buccal mucosal urethroplasty for long anterior urethral strictures (>4cm long using a perineal incision. Materials and Methods From August 2010 to August 2013, 20 patients underwent BMG urethroplasty. The cause of stricture was Lichen sclerosis in 12 cases (60%, Instrumentation in 5 cases (25%, and unknown in 3 cases (15%. Strictures were approached through a perineal skin incision and penis was invaginated into it to access the entire urethra. All the grafts were placed dorsolaterally, preserving the bulbospongiosus muscle, central tendon of perineum and one-sided attachement of corpus spongiosum. Procedure was considered to be failure if the patient required instrumentation postoperatively. Results Mean stricture length was 8.5cm (range 4 to 12cm. Mean follow-up was 22.7 months (range 12 to 36 months. Overall success rate was 85%. There were 3 failures (meatal stenosis in 1, proximal stricture in 1 and whole length recurrent stricture in 1. Other complications included wound infection, urethrocutaneous fistula, brownish discharge per urethra and scrotal oedema. Conclusion Dorsolateral buccal mucosal urethroplasty for long anterior urethral strictures using a single perineal incision is simple, safe and easily reproducible by urologists with a good outcome.

Natural gas industry in European Community and european single market

International Nuclear Information System (INIS)

Cadoret, I.

1992-01-01

Common Market of natural gas is dominated by some companies. In several Member Countries, one company only manages the whole industry. European Economic Community thinks this type of structure induce hindrances to free circulation of natural gas in Europe. 10 refs

Disturbance estimation and compensation for planar motors on the long-stroke stage of a wafer stage

Directory of Open Access Journals (Sweden)

Bizhong Xia

2015-04-01

Full Text Available This article presents a data-based method to estimate and compensate low-frequency disturbance in planar motors on the long-stroke stage of a wafer stage, which is a typical multiple-input multiple-output system. First, a data-based method is introduced to decouple the multiple-input multiple-output system into multi-single-input single-output system, which is crucial for the design of controller and the correction of disturbance estimation in the scanning direction. Second, dominant low-frequency disturbances in the long-stroke stage are analyzed. Third, estimation and compensation method under moving condition is proposed. The compensation method is based on three feedforward tables, and the tables are indexed by trajectory parameters, including velocity and position instead of time in the iterative learning control method. Finally, experiments are performed on the long-stroke stage of a wafer stage to verify the proposed method. Experimental results show that the proposed method can effectively improve the servo performance by reducing the tracking errors by nearly 1/2 in the forward direction and 1/3 in the backward direction and lowering error difference between the forward and backward directions from 5.1 to 1.2 µm.

Preparation and Loading Process of Single Crystalline Samples into a Gas Environmental Cell Holder for In Situ Atomic Resolution Scanning Transmission Electron Microscopic Observation.

Science.gov (United States)

Straubinger, Rainer; Beyer, Andreas; Volz, Kerstin

2016-06-01

A reproducible way to transfer a single crystalline sample into a gas environmental cell holder for in situ transmission electron microscopic (TEM) analysis is shown in this study. As in situ holders have only single-tilt capability, it is necessary to prepare the sample precisely along a specific zone axis. This can be achieved by a very accurate focused ion beam lift-out preparation. We show a step-by-step procedure to prepare the sample and transfer it into the gas environmental cell. The sample material is a GaP/Ga(NAsP)/GaP multi-quantum well structure on Si. Scanning TEM observations prove that it is possible to achieve atomic resolution at very high temperatures in a nitrogen environment of 100,000 Pa.

Reactive Power Control of Single-Stage Three-Phase Photovoltaic System during Grid Faults Using Recurrent Fuzzy Cerebellar Model Articulation Neural Network

Directory of Open Access Journals (Sweden)

Faa-Jeng Lin

2014-01-01

Full Text Available This study presents a new active and reactive power control scheme for a single-stage three-phase grid-connected photovoltaic (PV system during grid faults. The presented PV system utilizes a single-stage three-phase current-controlled voltage-source inverter to achieve the maximum power point tracking (MPPT control of the PV panel with the function of low voltage ride through (LVRT. Moreover, a formula based on positive sequence voltage for evaluating the percentage of voltage sag is derived to determine the ratio of the injected reactive current to satisfy the LVRT regulations. To reduce the risk of overcurrent during LVRT operation, a current limit is predefined for the injection of reactive current. Furthermore, the control of active and reactive power is designed using a two-dimensional recurrent fuzzy cerebellar model articulation neural network (2D-RFCMANN. In addition, the online learning laws of 2D-RFCMANN are derived according to gradient descent method with varied learning-rate coefficients for network parameters to assure the convergence of the tracking error. Finally, some experimental tests are realized to validate the effectiveness of the proposed control scheme.

Orbital single particle tracking on a commercial confocal microscope using piezoelectric stage feedback

International Nuclear Information System (INIS)

Lanzanò, L; Gratton, E

2014-01-01

Single Particle Tracking (SPT) is a technique used to locate fluorescent particles with nanometer precision. In the orbital tracking method the position of a particle is obtained analyzing the distribution of intensity along a circular orbit scanned around the particle. In combination with an active feedback this method allows tracking of particles in 2D and 3D with millisecond temporal resolution. Here we describe a SPT setup based on a feedback approach implemented with minimal modification of a commercially available confocal laser scanning microscope, the Zeiss LSM 510, in combination with an external piezoelectric stage scanner. The commercial microscope offers the advantage of a user-friendly software interface and pre-calibrated hardware components. The use of an external piezo-scanner allows the addition of feedback into the system but also represents a limitation in terms of its mechanical response. We describe in detail this implementation of the orbital tracking method and discuss advantages and limitations. As an example of application to live cell experiments we perform the 3D tracking of acidic vesicles in live polarized epithelial cells. (paper)

Kara-Kum gas

Energy Technology Data Exchange (ETDEWEB)

Gudz, A.

1975-05-01

Natural gas from the Shatlyk gas field in the Kara Kum Desert, Turkmenia, U.S.S.R., will soon be available to the European section of the U.S.S.R. with the recent completion of the 291-mi Shatlyk-Khiva gas pipeline and the completion of all associated production units by the end of the year. The gas field, with explored reserves of (1.5 trillion m/sup 3/), is expected to be producing (100 million m/sup 3//day) at the end of 1975. Diagonal profiling was used in the exploration stage to reduce the number of boreholes required from 16 to 11, saving about $6.7 million (5 million rubles) and cutting the exploration time by almost 2 y. Most of the boreholes, drilled within the contour of the gas-bearing structure, can be used for gas production. The gas, produced at 2352 psi and 205/sup 0/F, is cooled to 113/sup 0/F, stripped of condensate and moisture, metered, and treated before transmission.

A review of findings of a study of rocket based combined cycle engines applied to extensively axisymmetric single stage to orbit vehicles

Science.gov (United States)

Foster, Richard W.

1992-01-01

Extensively axisymmetric and non-axisymmetric Single Stage To Orbit (SSTO) vehicles are considered. The information is presented in viewgraph form and the following topics are presented: payload comparisons; payload as a percent of dry weight - a system hardware cost indicator; life cycle cost estimations; operations and support costs estimation; selected engine type; and rocket engine specific impulse calculation.

Fundamental Study of Disposition and Release of Methane in a Shale Gas Reservoir

Energy Technology Data Exchange (ETDEWEB)

Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Xiong, Yongliang [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Repository Performance; Criscenti, Louise J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geochemistry; Ho, Tuan Ahn [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geochemistry; Weck, Philippe F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Storage and Transportation Technology; Ilgen, Anastasia G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geochemistry; Matteo, Edward [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Kruichak, Jessica N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Mills, Melissa M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Nuclear Waste Disposal Research and Analysis; Dewers, Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Geomechanics; Gordon, Margaret E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Dept. of Materials, Devices and Energy Technologies; Akkutlu, Yucel [Texas A & M Univ., College Station, TX (United States). Dept. of Petroleum Engineering

2016-09-01

The recent boom in shale gas production through hydrofracturing has reshaped the energy production landscape in the United States. Wellbore production rates vary greatly among the wells within a single field and decline rapidly with time, thus bring up a serious concern with the sustainability of shale gas production. Shale gas production starts with creating a fracture network by injecting a pressurized fluid in a wellbore. The induced fractures are then held open by proppant particles. During production, gas releases from the mudstone matrix, migrates to nearby fractures, and ultimately reaches a production wellbore. Given the relatively high permeability of the induced fractures, gas release and migration in low-permeability shale matrix is likely to be a limiting step for long-term wellbore production. Therefore, a clear understanding of the underlying mechanisms of methane disposition and release in shale matrix is crucial for the development of new technologies to maximize gas production and recovery. Shale is a natural nanocomposite material with distinct characteristics of nanometer-scale pore sizes, extremely low permeability, high clay contents, significant amounts of organic carbon, and large spatial heterogeneities. Our work has shown that nanopore confinement plays an important role in methane disposition and release in shale matrix. Using molecular simulations, we show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~ 30 - 47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. The long-term production decline appears controlled by the second stage of gas release. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD

Program for aerodynamic performance tests of helium gas compressor model of the gas turbine high temperature reactor (GTHTR300)

International Nuclear Information System (INIS)

Takada, Shoji; Takizuka, Takakazu; Kunimoto, Kazuhiko; Yan, Xing; Itaka, Hidehiko; Mori, Eiji

2003-01-01

Research and development program for helium gas compressor aerodynamics was planned for the power conversion system of the Gas Turbine High Temperature Reactor (GTHTR300). The axial compressor with polytropic efficiency of 90% and surge margin more than 30% was designed with 3-dimensional aerodynamic design. Performance and surge margin of the helium gas compressor tends to be lower due to the higher boss ratio which makes the tip clearance wide relative to the blade height, as well as due to a larger number of stages. The compressor was designed on the basis of methods and data for the aerodynamic design of industrial open-cycle gas-turbine. To validate the design of the helium gas compressor of the GTHTR300, aerodynamic performance tests were planned, and a 1/3-scale, 4-stage compressor model was designed. In the tests, the performance data of the helium gas compressor model will be acquired by using helium gas as a working fluid. The maximum design pressure at the model inlet is 0.88 MPa, which allows the Reynolds number to be sufficiently high. The present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

GESIT: a thermodynamic program for single cycle gas turbine plants with and without intercoolers

Energy Technology Data Exchange (ETDEWEB)

Heil, J

1973-08-01

A computer program for the thermodynamic modeling of singlecycle gas turbine plants is described. A high-temperature reactor is assumed as a heat source in the program, but the HTR can be replaced with another heat source without difficulty. Starting from a set of independent data, the program calculates efficiencies and mass flows. It indicates all values for a heat and power balance and prints out the temperatures and pressures for the different parts of the cycle. Besides this, the program is able to optimize the compression ratios for minimal power input. It also takes into account turbine rotor cooling (at the roots of the blades). Furthermore, the program is able to use either total pressure loss or specified losses in different parts of the cycle. The program GESlT can also handle systems with one or two intercoolers, or with no intercooler. GESIT gives all input and output values for the heat exchangers and turbo-machines. First the single-cycle gas turbine plant is described. After that the computational basis for the program and the program structure is explained. Instructions for data input are given so that the program can be immediately utilized. An example of input data together with the associated output is presented. (auth)

Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Vernieres, Jerome, E-mail: Jerome.vernieres@oist.jp; Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Diaz, Rosa E. [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Bobo, Jean-François [Centre d’Elaboration de Materiaux et d’Etudes Structurales (CEMES), 29 rue Jeanne Marvig, 31055 Toulouse Cedex 4 (France); Sowwan, Mukhles, E-mail: Mukhles@oist.jp [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Nanotechnology Research Laboratory, Al-Quds University, P.O. Box 51000, East Jerusalem, Palestine (Country Unknown)

2014-11-01

Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO{sub 3} phase) and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g) and low coercivity (less than 20 Oe) at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

Single-stage multilevel soft-tissue surgery in the lower limbs with spastic cerebral palsy: Experience from a rehabilitation unit

Directory of Open Access Journals (Sweden)

Gupta Anupam

2008-01-01

Full Text Available Background: To assess the effect of single-stage multilevel soft-tissue surgery (Single Event Multiple Level Resections, SEMLR on deformities and locomotion in patients with cerebral palsy (CP with static contracture(s in lower limbs. Patients and Methods: Study included 34 patients (M:F, 23:11 with mean age of 9.53 ± 3.92 years (4-16 years. Among them 22 had diplegia and four each had quadriplegia and right and left hemiplegia. Fourteen patients (41.2% had their intelligence quotient (IQ in the normal range (IQ ≥ 80, while others had mental retardation (MR of varying severity: borderline MR (IQ = 70-79 in 12, mild MR (IQ = 50-69 in 5, and moderate MR (IQ = 35-49 in patients 3. All patients underwent surgery (total number of procedures 153, average 4.5 procedures/patient over a period of 30 months (April 2005 to September 2007. Improvement in functional abilities and locomotion was assessed using Gross Motor Functional Classification Scale (GMFCS scores and by physical examination. Results: Significant improvement in function was observed ( P = 0.000 after surgery when comparing the preoperative and postoperative GMFCS scores. All patients were maintaining ambulation at a mean follow-up duration of 13.12 ± 6.07 months (3-24 months, with five patients using knee-ankle-foot orthoses (KAFO, 22 using ankle-foot orthoses (AFO, and six patients using knee gaiters. Sixteen patients were using walker, and two were using crutches as assistive devices. Conclusion: This study suggests that CP patients with good trunk control and static contractures at multiple joints in the lower limbs can be made ambulant with single-stage multilevel soft-tissue surgery. It has to be a team effort of the surgeon and the rehabilitation team in the postoperative period for the attainment of satisfactory goal.

World`s first fuel cell in a single-family home - The VNG natural gas house: Low-emission energy meets all household needs

Energy Technology Data Exchange (ETDEWEB)

Anon.

1999-03-01

VNG - Verbundnetz Gas Aktiengesellschaft of Leipzig, Germany, has pioneered the development of a decentral home energy system combining very high efficiencies with extremely low emissions. The company has installed the world`s first fuel cell total energy system using natural gas as an energy source to generate both heat and power in a single-family home. It replaces the gas-fired mini power station operated as part of the VNG natural gas house project which was instrumental in the rapid advancement of small-scale co-generation technology. The objective of VNG and its project partners is to collect reliable data for advancing fuel cell technology development, allowing appliance manufacturers to design a competitive system for introduction on the market within a few years. Discerning consumers will then be able to opt for an innovative, highly efficient system to meet all their household energy needs. (orig.)

Intensification of oxidative desulfurization of gas oil by ultrasound irradiation: Optimization using Box–Behnken design (BBD)

International Nuclear Information System (INIS)

Jalali, Mohammad Reza; Sobati, Mohammad Amin

2017-01-01

Highlights: • Ultrasound-assisted oxidative desulfurization (UAOD) of gas oil was studied. • The influences of the different operating parameters were investigated. • Response surface methodology (RSM) was used to find the best operating parameters. • An accurate correlation was developed for the sulfur removal. • Ultrasound-assisted desulfurization process was compared with conventional process. - Abstract: In the present work, ultrasound assisted oxidative desulfurization (UAOD) of gas oil as the feedstock with sulfur content of 2210 ppmw was investigated using a mixture of hydrogen peroxide and formic acid as the oxidant and catalyst, respectively. The influences of main process variables such as sonication time (2–30 min), oxidation temperature (40–70 °C), hydrogen peroxide to sulfur molar ratio (10–50), formic acid to oxidant molar ratio (2–4), ultrasound power per gas oil volume (5.56–8.89 W/mL), and number of extraction stages (1–4) on the sulfur removal of gas oil were investigated. Response surface methodology (RSM) based on Box–Behnken design (BBD) and single-factor experiments were employed. The best performance of UAOD process for gas oil was achieved at 50 °C of reaction temperature, oxidant to sulfur molar ratio of 46.36, formic acid to oxidant molar ratio of 3.22, sonication time of 19.81 min, and 7.78 W/mL as the ultrasound power per gas oil volume. The sulfur removal of UAOD process was evaluated after oxidation under the abovementioned conditions followed by (a) one stage extraction and (b) four stages extraction using acetonitrile as solvent. The observed sulfur removal was 87 for case (a) and 96.2% for case (b). The UAOD process was also compared with conventional ODS process. Considerable improvement on the sulfur removal was observed specially in lower reaction time in the case of using ultrasound irradiation in comparison with conventional mixing.

Parametric studies on different gas turbine cycles for a high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Wang Jie; Gu Yihua

2005-01-01

The high temperature gas-cooled reactor (HTGR) coupled with turbine cycle is considered as one of the leading candidates for future nuclear power plants. In this paper, the various types of HTGR gas turbine cycles are concluded as three typical cycles of direct cycle, closed indirect cycle and open indirect cycle. Furthermore they are theoretically converted to three Brayton cycles of helium, nitrogen and air. Those three types of Brayton cycles are thermodynamically analyzed and optimized. The results show that the variety of gas affects the cycle pressure ratio more significantly than other cycle parameters, however, the optimized cycle efficiencies of the three Brayton cycles are almost the same. In addition, the turbomachines which are required for the three optimized Brayton cycles are aerodynamically analyzed and compared and their fundamental characteristics are obtained. Helium turbocompressor has lower stage pressure ratio and more stage number than those for nitrogen and air machines, while helium and nitrogen turbocompressors have shorter blade length than that for air machine

Physical simulation of gas reservoir formation in the Liwan 3-1 deep-water gas field in the Baiyun sag, Pearl River Mouth Basin

Directory of Open Access Journals (Sweden)

Gang Gao

2015-01-01

Full Text Available To figure out the process and controlling factors of gas reservoir formation in deep-waters, based on an analysis of geological features, source of natural gas and process of reservoir formation in the Liwan 3-1 gas field, physical simulation experiment of the gas reservoir formation process has been performed, consequently, pattern and features of gas reservoir formation in the Baiyun sag has been found out. The results of the experiment show that: ① the formation of the Liwan 3-1 faulted anticline gas field is closely related to the longstanding active large faults, where natural gas is composed of a high proportion of hydrocarbons, a small amount of non-hydrocarbons, and the wet gas generated during highly mature stage shows obvious vertical migration signs; ② liquid hydrocarbons associated with natural gas there are derived from source rock of the Enping & Zhuhai Formation, whereas natural gas comes mainly from source rock of the Enping Formation, and source rock of the Wenchang Formation made a little contribution during the early Eocene period as well; ③ although there was gas migration and accumulation, yet most of the natural gas mainly scattered and dispersed due to the stronger activity of faults in the early period; later as fault activity gradually weakened, gas started to accumulate into reservoirs in the Baiyun sag; ④ there is stronger vertical migration of oil and gas than lateral migration, and the places where fault links effective source rocks with reservoirs are most likely for gas accumulation; ⑤ effective temporal-spatial coupling of source-fault-reservoir in late stage is the key to gas reservoir formation in the Baiyun sag; ⑥ the nearer the distance from a trap to a large-scale fault and hydrocarbon source kitchen, the more likely gas may accumulate in the trap in late stage, therefore gas accumulation efficiency is much lower for the traps which are far away from large-scale faults and hydrocarbon source

The diversity of the effects of sulfur mustard gas inhalation on respiratory system 10 years after a single, heavy exposure: analysis of 197 cases.

Science.gov (United States)

Emad, A; Rezaian, G R

1997-09-01

To find out the late pulmonary sequelae of sulfur mustard gas inhalation in 197 veterans, 10 years after their exposure. Cross-sectional clinical study. University hospital. One hundred ninety-seven veterans with a single, heavy exposure to sulfur mustard gas in 1986 and 86 nonexposed veterans as their control group. Pulmonary function tests, carbon monoxide diffusion capacity, bronchoscopy, and high-resolution CT of the chest were performed in all patients. Transbronchial lung biopsy was done in 24 suspected cases of pulmonary fibrosis. Asthma was diagnosed in 21 (10.65%), chronic bronchitis in 116 (58.88%), bronchiectasis in 17 (8.62%), airway narrowing due to searing or granulation tissue in 19 (9.64%), and pulmonary fibrosis in 24 (12.18%) cases. None of these were found among the control group except for a single case of chronic bronchitis. Although the respiratory symptoms of an acute sulfur mustard gas inhalation are usually transient and nonspecific, it can lead to the development of a series of chronic destructive pulmonary sequelae in such cases.

The RealGas and RealGasH2O Options of the TOUGH+ Code for the Simulation of Coupled Fluid and Heat Flow in Tight/Shale Gas Systems

Energy Technology Data Exchange (ETDEWEB)

Moridis, George; Freeman, Craig

2013-09-30

We developed two new EOS additions to the TOUGH+ family of codes, the RealGasH2O and RealGas . The RealGasH2O EOS option describes the non-isothermal two-phase flow of water and a real gas mixture in gas reservoirs, with a particular focus in ultra-tight (such as tight-sand and shale gas) reservoirs. The gas mixture is treated as either a single-pseudo-component having a fixed composition, or as a multicomponent system composed of up to 9 individual real gases. The RealGas option has the same general capabilities, but does not include water, thus describing a single-phase, dry-gas system. In addition to the standard capabilities of all members of the TOUGH+ family of codes (fully-implicit, compositional simulators using both structured and unstructured grids), the capabilities of the two codes include: coupled flow and thermal effects in porous and/or fractured media, real gas behavior, inertial (Klinkenberg) effects, full micro-flow treatment, Darcy and non-Darcy flow through the matrix and fractures of fractured media, single- and multi-component gas sorption onto the grains of the porous media following several isotherm options, discrete and fracture representation, complex matrix-fracture relationships, and porosity-permeability dependence on pressure changes. The two options allow the study of flow and transport of fluids and heat over a wide range of time frames and spatial scales not only in gas reservoirs, but also in problems of geologic storage of greenhouse gas mixtures, and of geothermal reservoirs with multi-component condensable (H2O and CH4) and non-condensable gas mixtures. The codes are verified against available analytical and semi-analytical solutions. Their capabilities are demonstrated in a series of problems of increasing complexity, ranging from isothermal flow in simpler 1D and 2D conventional gas reservoirs, to non-isothermal gas flow in 3D fractured shale gas reservoirs involving 4 types of fractures, micro-flow, non-Darcy flow and gas

The Integrity of ACSR Full Tension Single-Stage Splice Connector at Higher Operation Temperature

Energy Technology Data Exchange (ETDEWEB)

Wang, Jy-An John [ORNL; Lara-Curzio, Edgar [ORNL; King Jr, Thomas J [ORNL

2008-10-01

Due to increases in power demand and limited investment in new infrastructure, existing overhead power transmission lines often need to operate at temperatures higher than those used for the original design criteria. This has led to the accelerated aging and degradation of splice connectors. It is manifested by the formation of hot-spots that have been revealed by infrared imaging during inspection. The implications of connector aging is two-fold: (1) significant increases in resistivity of the splice connector (i.e., less efficient transmission of electricity) and (2) significant reductions in the connector clamping strength, which could ultimately result in separation of the power transmission line at the joint. Therefore, the splice connector appears to be the weakest link in electric power transmission lines. This report presents a protocol for integrating analytical and experimental approaches to evaluate the integrity of full tension single-stage splice connector assemblies and the associated effective lifetime at high operating temperature.

On the stabilization of gas discharge by an hf-electric field

International Nuclear Information System (INIS)

Rakhimova, T.V.; Rakhimov, A.T.

1975-01-01

It is shown that when the bulk gas discharge is placed in an hf-electric field of sufficiently high frequency in the process of gas discharge burning there appears a long phase during which the gas ionization is inessential and the discharge burns in a recombining plasma. Such a stage may affect the stability of a gas discharge. It is shown also that at comparable values of intensities of the d.c. and hf electric fields there is a small parameter for the weakly-ionized plasma in which the relative portion of energy introduced into the discharge during the stage of gas ionization may be sufficiently small. (Auth.)

Creep in single crystals of γ single phase Ni-20Cr alloy and evolution of dynamic recrystallization

International Nuclear Information System (INIS)

Matsuo, T.; Terada, Y.; Takahashi, S.; Ishiwari, Y.

2000-01-01

The creep rate - time and the creep rate - strain curves of the single crystals of γ single phase Ni-20 mass%Cr alloy have been investigated at 1173 K under the wide stress range of 19.6 to 98 MPa, and compared with those of polycrystals. The orientation corresponding to the stress axis of the single crystals were chosen within the standard stereographic triangle. The creep curve in the Ni-20 mass%Cr single crystal consists of a transient stage and an accelerating stage without a steady state stage. The transient stage has two steps. In the first step, the creep rate slightly decreases, and in the second step, the decrease in creep rate becomes prominent with increasing the testing time. With decreasing the stress, the extension of transient stage becomes prominent, and by this extension, the decreasing ratio of the creep rate in transient stage is enlarged. At the lowest stress of 19.6 MPa, the most prominent extension of transient stage and the more than two order decrease in creep rate in transient stage are detected. The creep interrupting tests have been conducted at the stress of 29.4 MPa in the strain range of 0.1 to 0.6 to examine the appearance of dynamically recrystallized grains. At the strain of 0.1 corresponding to the end of the first step in transient stage, a straight subboundary parallel to slip plane appears in a wide distance of a few hundreds micrometers. With increasing the strain, the straight subboundary turns to waved one. At the strain showing the minimum creep rate, a lot of evolved subgrains appear. At the strain corresponding to the early stage of accelerating creep, dynamically recrystallized grains appear. It is confirmed that the onset of accelerating creep well corresponds to the appearance of dynamically recrystallized grains. In the single crystal creep ruptured, the whole gage portion turns to polycrystal with equiaxed grains having a diameter of 150 μm. (orig.)

Single stage reduction and stabilization of basilar invagination after failed prior fusion surgery in children with Down's syndrome.

Science.gov (United States)

Hedequist, Daniel; Bekelis, Kimon; Emans, John; Proctor, Mark R

2010-02-15

We describe an innovative single-stage reduction and stabilization technique using modern cervical instrumentation. We hypothesis modern instrumentation has made more aggressive surgical corrections possible and has reduced the need for transoral resection of the odontoid and traction reduction in children with basilar invagination. Craniocervical junction abnormalities, including atlantoaxial instability and progressive basilar invagination, are relatively common phenomenon in Down's syndrome patients, and can lead to chronic progressive neurologic deficits, catastrophic injury, and death. This patient population also can be a difficult one in which to perform successful stabilization and fusion. We reviewed the records and films on 2 children with Down's syndrome and atlantoaxial instability who had undergone prior occipital-cervical fusion and then presented with symptomatic progressive basilar invagination due to atlantoaxial displacement. In both cases, the children had progressive symptoms of spinal cord and brain stem compression. Multiple approaches for surgical correction, including preoperative traction and transoral odontoid resection, were considered, but ultimately it was elected to perform a single stage posterior operation. In both patients, we performed fusion takedown, intraoperative realignment with reduction of the basilar invagination, and stabilization using modern occipito-cervical instrumentation. In both children, excellent cranio-cervical realignment was achieved; along with successful fusion and improvement in clinical symptoms. In this article we will discuss the clinical cases and review the background of craniocervical junction abnormalities in Down's syndrome patients. We hypothesis modern instrumentation has made more aggressive surgical corrections possible and has reduced the need for transoral resection of the odontoid and traction reduction in children with basilar invagination.

A novel, fast and efficient single-sensor automatic sleep-stage classification based on complementary cross-frequency coupling estimates.

Science.gov (United States)

Dimitriadis, Stavros I; Salis, Christos; Linden, David

2018-04-01

Limitations of the manual scoring of polysomnograms, which include data from electroencephalogram (EEG), electro-oculogram (EOG), electrocardiogram (ECG) and electromyogram (EMG) channels have long been recognized. Manual staging is resource intensive and time consuming, and thus considerable effort must be spent to ensure inter-rater reliability. As a result, there is a great interest in techniques based on signal processing and machine learning for a completely Automatic Sleep Stage Classification (ASSC). In this paper, we present a single-EEG-sensor ASSC technique based on the dynamic reconfiguration of different aspects of cross-frequency coupling (CFC) estimated between predefined frequency pairs over 5 s epoch lengths. The proposed analytic scheme is demonstrated using the PhysioNet Sleep European Data Format (EDF) Database with repeat recordings from 20 healthy young adults. We validate our methodology in a second sleep dataset. We achieved very high classification sensitivity, specificity and accuracy of 96.2 ± 2.2%, 94.2 ± 2.3%, and 94.4 ± 2.2% across 20 folds, respectively, and also a high mean F1 score (92%, range 90-94%) when a multi-class Naive Bayes classifier was applied. High classification performance has been achieved also in the second sleep dataset. Our method outperformed the accuracy of previous studies not only on different datasets but also on the same database. Single-sensor ASSC makes the entire methodology appropriate for longitudinal monitoring using wearable EEG in real-world and laboratory-oriented environments. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

A perspective on Canadian shale gas

Energy Technology Data Exchange (ETDEWEB)

Johnson, Mike; Davidson, Jim; Mortensen, Paul

2010-09-15

In a relatively new development over just the past few years, shale formations are being targeted for natural gas production. Based on initial results, there may be significant potential for shale gas in various regions of Canada, not only in traditional areas of conventional production but also non-traditional areas. However, there is much uncertainty because most Canadian shale gas production is currently in experimental or early developmental stages. Thus, its full potential will not be known for some time. If exploitation proves to be successful, Canadian shale gas may partially offset projected long-term declines in Canadian conventional natural gas production.

A Rocket Powered Single-Stage-to-Orbit Launch Vehicle With U.S. and Soviet Engineers

Science.gov (United States)

MacConochie, Ian O.; Stnaley, Douglas O.

1991-01-01

A single-stage-to-orbit launch vehicle is used to assess the applicability of Soviet Energia high-pressure-hydrocarbon engine to advanced U.S. manned space transportation systems. Two of the Soviet engines are used with three Space Shuttle Main Engines. When applied to a baseline vehicle that utilized advanced hydrocarbon engines, the higher weight of the Soviet engines resulted in a 20 percent loss of payload capability and necessitated a change in the crew compartment size and location from mid-body to forebody in order to balance the vehicle. Various combinations of Soviet and Shuttle engines were evaluated for comparison purposes, including an all hydrogen system using all Space Shuttle Main Engines. Operational aspects of the baseline vehicle are also discussed. A new mass properties program entitles Weights and Moments of Inertia (WAMI) is used in the study.

Single cell analysis facilitates staging of Blimp1-dependent primordial germ cells derived from mouse embryonic stem cells.

Directory of Open Access Journals (Sweden)

John J Vincent

Full Text Available The cell intrinsic programming that regulates mammalian primordial germ cell (PGC development in the pre-gonadal stage is challenging to investigate. To overcome this we created a transgene-free method for generating PGCs in vitro (iPGCs from mouse embryonic stem cells (ESCs. Using labeling for SSEA1 and cKit, two cell surface molecules used previously to isolate presumptive iPGCs, we show that not all SSEA1+/cKit+ double positive cells exhibit a PGC identity. Instead, we determined that selecting for cKit(bright cells within the SSEA1+ fraction significantly enriches for the putative iPGC population. Single cell analysis comparing SSEA1+/cKit(bright iPGCs to ESCs and embryonic PGCs demonstrates that 97% of single iPGCs co-express PGC signature genes Blimp1, Stella, Dnd1, Prdm14 and Dazl at similar levels to e9.5-10.5 PGCs, whereas 90% of single mouse ESC do not co-express PGC signature genes. For the 10% of ESCs that co-express PGC signature genes, the levels are significantly lower than iPGCs. Microarray analysis shows that iPGCs are transcriptionally distinct from ESCs and repress gene ontology groups associated with mesoderm and heart development. At the level of chromatin, iPGCs contain 5-methyl cytosine bases in their DNA at imprinted and non-imprinted loci, and are enriched in histone H3 lysine 27 trimethylation, yet do not have detectable levels of Mvh protein, consistent with a Blimp1-positive pre-gonadal PGC identity. In order to determine whether iPGC formation is dependent upon Blimp1, we generated Blimp1 null ESCs and found that loss of Blimp1 significantly depletes SSEA1/cKit(bright iPGCs. Taken together, the generation of Blimp1-positive iPGCs from ESCs constitutes a robust model for examining cell-intrinsic regulation of PGCs during the Blimp1-positive stage of development.

Recent developments of a two-stage light gas gun for pellet injection

International Nuclear Information System (INIS)

Reggiori, A.

1984-01-01

A report is given on a two-stage pneumatic gun operated with ambient air as first stage driver which has been built and tested. Cylindrical polyethylene pellets of 1 mm diameter and 1 mm length have been launched at velocities up to 1800 m/s, with divergence angles of the pellet trajectory less than 1 0 . It is possible to optimize the pressure pulse for pellets of different masses, simply changing the mass of the piston and/or the initial pressures in the second stage. (author)

Gas to Power in China. Gas-fired Power in China. Clearing the policy bottleneck

International Nuclear Information System (INIS)

Chen, Xavier

2005-12-01

Policy for gas-fired power is the single most serious and common issue that needs urgent resolution for all China's current and future gas projects, including LNG projects. This was the main conclusion of a national seminar on gas industry development policy that was held in July 2004. At the time of writing this paper, such a policy is still missing. In order to reduce pollution, improve energy security and meet the needs of the ever-growing economy for high-quality energies, the Chinese government has declared its firm intention to develop a natural gas market. The official target is to develop a gas market of 200 bcm/a by 2020, five times of the current size of around 40 bcm/a. Domestic supply is expected to provide 120 bcm/a, with the rest (80 bcm/a) by gas imports either in the form of piped gas or LNG. Gas-fired power generation plays a critical role in developing a sizeable gas market, especially for large-scale pipeline and LNG projects. Similar to the Guangdong and Fujian LNG projects where gas-fired power accounts for approximately 60% and 70% respectively of the first phase gas volume, each of the proposed LNG projects has allocated a large portion of the gas off-take volume to the power sector. In addition to the first two commercial CCGT plants that were commissioned in 2005, there are over 20 projects totalling 18 GW of capacity under construction. By 2020, China's planners foresee a total gas-fired power capacity of 60 GW, accounting for around 6% of the total installed capacity in the country. Despite these impressive projections, gas-fired power faces significant uncertainties in China: (1) there is an ongoing debate on whether China should develop gas-fired power, given the relative scarcity and higher cost of gas; (2) high gas prices and imported equipment limit the competitiveness of gas-fired power relative to a coal-fired one; (3) it lacks policy support. For the moment, gas-fired power plants are required to participate in a yet

The effect of seasonal harvesting on a single-species discrete population model with stage structure and birth pulses

International Nuclear Information System (INIS)

Gao Shujing; Chen Lansun

2005-01-01

In this paper, we propose an exploited single-species discrete model with stage structure for the dynamics in a fish population for which births occur in a single pulse once per time period. Using the stroboscopic map, we obtain an exact cycle of the system, and obtain the threshold conditions for its stability. Bifurcation diagrams are constructed with the birth rate as the bifurcation parameter, and these are observed to display complex dynamic behaviors, including chaotic bands with period windows, pitch-fork and tangent bifurcation. This suggests that birth pulse provides a natural period or cyclicity that makes the dynamical behavior more complex. Moreover, we show that the timing of harvesting has a strong impact on the persistence of the fish population, on the volume of mature fish stock and on the maximum annual-sustainable yield. An interesting result is obtained that, after the birth pulse, the earlier culling the mature fish, the larger harvest can tolerate

Performance Evaluation of Staged Bosch Process for CO2 Reduction to Produce Life Support Consumables

Science.gov (United States)

Vilekar, Saurabh A.; Hawley, Kyle; Junaedi, Christian; Walsh, Dennis; Roychoudhury, Subir; Abney. Morgan B.; Mansell, James M.

2012-01-01

Utilizing carbon dioxide to produce water and hence oxygen is critical for sustained manned missions in space, and to support both NASA's cabin Atmosphere Revitalization System (ARS) and In-Situ Resource Utilization (ISRU) concepts. For long term missions beyond low Earth orbit, where resupply is significantly more difficult and costly, open loop ARS, like Sabatier, consume inputs such as hydrogen. The Bosch process, on the other hand, has the potential to achieve complete loop closure and is hence a preferred choice. However, current single stage Bosch reactor designs suffer from a large recycle penalty due to slow reaction rates and the inherent limitation in approaching thermodynamic equilibrium. Developmental efforts are seeking to improve upon the efficiency (hence reducing the recycle penalty) of current single stage Bosch reactors which employ traditional steel wool catalysts. Precision Combustion, Inc. (PCI), with support from NASA, has investigated the potential for utilizing catalysts supported over short-contact time Microlith substrates for the Bosch reaction to achieve faster reaction rates, higher conversions, and a reduced recycle flows. Proof-of-concept testing was accomplished for a staged Bosch process by splitting the chemistry in two separate reactors, first being the reverse water-gas-shift (RWGS) and the second being the carbon formation reactor (CFR) via hydrogenation and/or Boudouard. This paper presents the results from this feasibility study at various operating conditions. Additionally, results from two 70 hour durability tests for the RWGS reactor are discussed.

Innovation-driven efficient development of the Longwangmiao Fm large-scale sulfur gas reservoir in Moxi block, Sichuan Basin

Directory of Open Access Journals (Sweden)

Xinhua Ma

2016-03-01

Full Text Available The Lower Cambrian Longwangmiao Fm gas reservoir in Moxi block of the Anyue Gas field, Sichuan Basin, is the largest single-sandbody integrated carbonate gas reservoir proved so far in China. Notwithstanding this reservoir's advantages like large-scale reserves and high single-well productivity, there are multiple complicated factors restricting its efficient development, such as a median content of hydrogen sulfide, low porosity and strong heterogeneity of fracture–cave formation, various modes of gas–water occurrences, and close relation between overpressure and stress sensitivity. Up till now, since only a few Cambrian large-scale carbonate gas reservoirs have ever been developed in the world, there still exists some blind spots especially about its exploration and production rules. Besides, as for large-scale sulfur gas reservoirs, the exploration and construction is costly, and production test in the early evaluation stage is severely limited, all of which will bring about great challenges in productivity construction and high potential risks. In this regard, combining with Chinese strategic demand of strengthening clean energy supply security, the PetroChina Southwest Oil & Gas Field Company has carried out researches and field tests for the purpose of providing high-production wells, optimizing development design, rapidly constructing high-quality productivity and upgrading HSE security in the Longwangmiao Fm gas reservoir in Moxi block. Through the innovations of technology and management mode within 3 years, this gas reservoir has been built into a modern large-scale gas field with high quality, high efficiency and high benefit, and its annual capacity is now up to over 100 × 108 m3, with a desirable production capacity and development indexes gained as originally anticipated. It has become a new model of large-scale gas reservoirs with efficient development, providing a reference for other types of gas reservoirs in China.

Single-stage Kanban system with deterioration failures and condition-based preventive maintenance

International Nuclear Information System (INIS)

Xanthopoulos, A.S.; Koulouriotis, D.E.; Botsaris, P.N.

2015-01-01

Despite the fact that the fields of pull type production control policies and condition-based preventive maintenance have much in common contextually, they have evolved independently up to now. In this investigation, an attempt is made to bridge the gap between these two branches of knowledge by introducing the single-stage Kanban system with deterioration failures and condition-based preventive maintenance. The formalism of continuous time Markov chains is used to model the system and expressions for eight performance metrics are derived. Two important, from a managerial perspective, constrained optimization problems for the proposed model are defined where the objective is the simultaneous optimization of the Kanban policy, the preventive maintenance policy and the inspection schedule under conflicting performance criteria. Multiple instances of each optimization problem are solved by means of the augmented Lagrangian genetic algorithm. The results from the optimization trials coupled by the results from extensive numerical examples facilitate the thorough investigation of the system’s behaviour. - Highlights: • Kanban system with deterioration failures and preventive maintenance is introduced. • The system is modeled as a continuous time Markov chain. • Expressions for eight performance metrics are derived. • The behavior of the system is studied through numerical examples. • Optimization results for selected performance metrics are presented

Radioactive rare gas separation using a separation cell with two kinds of membrane differing in gas permeability tendency

International Nuclear Information System (INIS)

Ohno, Masayoshi; Ozaki, Osamu; Sato, Hajime; Kimura, Shoji; Miyauchi, Terukatsu.

1977-01-01

A separation cell embodying two kinds of membrane-porous and nonporous, i.e. differing in gas permeability - has a separation factor higher than possible with a conventional separation cell with a single kind of membrane. The performance of such separation cells and of cascades constituted thereof are analyzed theoretically and measured experimentally for different conditions of operation, to determine the applicability of the concept to the separation of rare gases from gaseous waste out of nuclear plants. Theoretical considerations indicate that, in a cascade composed of symmetric separation cells, the separation performance can be improved by recycling part of the effluent from a cell back through the same cell (recycling cascade). It is shown that its performance is better than with the arrangement of diverting another effluent several stages upstream. With the recycling cascade, the symmetric separation recycling rate is determined by the depletion separation and enrichment separation factors relevant to the respective membranes. The separation performance of a 9-stage recycling cascade composed of separation cells with silicone rubber tubular membranes and cellulose acetate tubular membranes is derived for a case of Kr separation from N 2 -Kr mixture. The experimental data coincide well with the analytical results. From both the experimental and the analytical results, it is found that the attainable separation coefficient per stage of the cascade comes to average approximately 0.97. (auth.)

Towards Large Eddy Simulation of gas turbine compressors

Science.gov (United States)

McMullan, W. A.; Page, G. J.

2012-07-01

With increasing computing power, Large Eddy Simulation could be a useful simulation tool for gas turbine axial compressor design. This paper outlines a series of simulations performed on compressor geometries, ranging from a Controlled Diffusion Cascade stator blade to the periodic sector of a stage in a 3.5 stage axial compressor. The simulation results show that LES may offer advantages over traditional RANS methods when off-design conditions are considered - flow regimes where RANS models often fail to converge. The time-dependent nature of LES permits the resolution of transient flow structures, and can elucidate new mechanisms of vorticity generation on blade surfaces. It is shown that accurate LES is heavily reliant on both the near-wall mesh fidelity and the ability of the imposed inflow condition to recreate the conditions found in the reference experiment. For components embedded in a compressor this requires the generation of turbulence fluctuations at the inlet plane. A recycling method is developed that improves the quality of the flow in a single stage calculation of an axial compressor, and indicates that future developments in both the recycling technique and computing power will bring simulations of axial compressors within reach of industry in the coming years.

Compositional simulations of producing oil-gas ratio behaviour in low permeable gas condensate reservoir

OpenAIRE

Gundersen, Pål Lee

2013-01-01

Master's thesis in Petroleum engineering Gas condensate flow behaviour below the dew point in low permeable formations can make accurate fluid sampling a difficult challenge. The objective of this study was to investigate the producing oil-gas ratio behaviour in the infinite-acting period for a low permeable gas condensate reservoir. Compositional isothermal flow simulations were performed using a single-layer, radial and two-dimensional, gas condensate reservoir model with low permeabili...

Natural gas developments in Latin America

International Nuclear Information System (INIS)

Faith, P.L.

1996-01-01

Natural gas opportunities in Latin America are discussed with reference to the Bolivia to Brazil Gas Pipeline Project. This fully integrated natural gas project extends from reserves development to market consumption and involves cooperation between countries and between the public and private sector. The project's success will depend, it is argued on the thorough integration and cooperation of all stages from reserve exploration, through pipeline construction, and distribution to power generation. (UK)

OPEC and natural gas

International Nuclear Information System (INIS)

Samsam Bakhtiari, A.M.; Shahbudaghlou, F.

1998-01-01

This paper reviews the involvement of OPEC Member Countries in the natural gas industry in the past, present and future. It notes a tenfold increase in marketed production and a fourfold rise in re-injection since 1970. Collectively, Members now hold 41 per cent of the world's proven gas reserves and account for 20 per cent of exports. Individually, four of these countries hold position 2-5 in the world gas reserve rankings. Within OPEC, however, there remains an emphasis of oil over gas, not least because of oil's favourable position with regard to revenue-generation and profitability. As global demand continues on its upward growth curve in a more environmentally aware world, OPEC's gas horizons will widen. OPEC's strong reserve base will give its Members an undeniable role to play on the future global gas stage. However, these countries will give priority to domestic usage, particularly re-injection schemes

Data supporting the validation of a simulation model for multi-component gas separation in polymeric membranes.

Science.gov (United States)

Giordano, Lorena; Roizard, Denis; Bounaceur, Roda; Favre, Eric

2016-12-01

The article describes data concerning the separation performances of polymeric hollow-fiber membranes. The data were obtained using a model for simulating gas separation, described in the research article entitled "Interplay of inlet temperature and humidity on energy penalty for CO 2 post-combustion capture: rigorous analysis and simulation of a single stage gas permeation process" (L. Giordano, D. Roizard, R. Bounaceur, E. Favre, 2016) [1]. The data were used to validate the model by comparison with literature results. Considering a membrane system based on feed compression only, data from the model proposed and that from literature were compared with respect to the molar composition of permeate stream, the membrane area and specific energy requirement, varying the feed pressure and the CO 2 separation degree.

Advanced CFD modelling of air and recycled flue gas staging in a waste wood-fired grate boiler for higher combustion efficiency and greater environmental benefits.